tag:theconversation.com,2011:/nz/topics/uc-grad-slam-2015-18531/articlesUC Grad Slam 2015 – The Conversation2016-02-04T13:40:27Ztag:theconversation.com,2011:article/497282016-02-04T13:40:27Z2016-02-04T13:40:27ZHow humans threaten pumas just by being nearby<figure><img src="https://images.theconversation.com/files/99742/original/image-20151026-18440-1t7gp1v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A puma and her two kittens look out over San Jose, California.</span> <span class="attribution"><span class="source">Cchristopher Fust</span>, <span class="license">Author provided</span></span></figcaption></figure><p>You are wandering in the forest where you live, thinking about what you are going to have for dinner. Among the familiar calls of chickadees, you hear a foreign sound. You crouch in hiding, frightened for yourself and your family. Not until nightfall does the noise abate, allowing you to move again under the cloak of darkness. Soon you learn that the sounds come from unfamiliar beings taking over your homeland. You learn to live in hiding, believing that as soon as you let your guard down you may pay the ultimate price.</p>
<p>This is not the premise of a zombie apocalypse movie. It is the story of human expansion into wild places, where the wildlife that coexists with us often lives in chronic fear of humans. </p>
<p>Disturbance by humans changes the behavior of animals near towns, along roads and in areas that we use for mining, energy development and recreation. Although conservationists are starting to consider how the presence of humans affects the behavior of some species, they rarely analyze how these changes in animals’ behavior affects entire ecosystems. In my research examining pumas, or mountain lions, in California, I’ve found that our presence alters how they hunt for deer, which can have a significant effect on the ecosystem overall.</p>
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<span class="caption">Deer killed by puma in a residential area of the Santa Cruz Mountains.</span>
<span class="attribution"><span class="source">Justine A. Smith</span></span>
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<h2>Fear factor</h2>
<p>Fear is a powerful force in ecosystems. For decades, ecologists have acknowledged that fear can dictate when, where, and what animals eat, what habitats they use and how they communicate with one another. These behavioral changes in animals are ecologically important because they can change interactions among species. Although many animals are known to respond fearfully to their predators, we are only beginning to understand how humans elicit the same responses in wildlife.</p>
<p>In the Santa Cruz Mountains of California, I am studying how fear of humans in a top predator, the puma, resonates throughout the ecosystem. The Santa Cruz Mountains are isolated from other natural areas, bordered by the Pacific Ocean on the west, the San Francisco Bay metropolitan area on the north, and a major highway on the east. Like many places across the country, this region is dotted with residential developments and land utilized for mining and logging. However, it also contains open space preserves and state and county parks that provide important high-quality habitat for wildlife. </p>
<p>This kind of multi-use and fragmented landscape is increasingly becoming the norm in places where humans encroach on wild lands. To keep developing areas as wild as possible, we need to conserve natural animal behaviors and relationships.</p>
<h2>Scaredy cats</h2>
<p>With my colleagues at the <a href="http://santacruzpumas.org/">Santa Cruz Puma Project</a>, I am studying how human disturbances indirectly affect the behavior of pumas, the last remaining large carnivores in our region that roam the ravines between ridges lined with houses. We have <a href="https://doi.org/10.1371/journal.pone.0060590">found</a> that pumas attempt to avoid people, but their sensitivity to disturbance depends on what the cats are doing. Although pumas consistently travel and kill prey relatively close to human developments, they make their dens and communicate with each other through scent marking in areas far from zones that humans have altered. </p>
<p>In many types of ecosystems, researchers have observed that animals will <a href="https://doi.org/10.1139/z90-092">avoid feeding opportunities</a> when they fear a predator. To see whether the presence of humans was having this effect on pumas, I examined behavioral changes at kill sites in areas of the Santa Cruz Mountains with varying levels of human activity. To find these kill sites, our team tracked GPS-collared pumas using their locations and searched for prey remains. I then used data from the GPS collars to learn how behavior at these kill changed near human development. </p>
<p>Surprisingly, I <a href="https://doi.org/10.1098/rspb.2014.2711">found</a> that pumas often kill deer near human residences. However, unlike in wild areas where pumas stay close to their kills for a few days while they feed, pumas in developed areas leave their kills and move away from humans to rest, returning to feed only after dark. This causes pumas to waste energy by spending more time on the move, while losing opportunities to feed on their kills. Moreover, pumas that hunt in the most disturbed areas kill 36 percent more deer than pumas in the most rural areas. We believe that pumas ranging near developed areas kill more deer because they cannot fully consume their prey while also avoiding interactions with humans. </p>
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<span class="caption">Warning sign at Los Trancos Open Space Reserve, San Mateo County, California.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/kmanohar/3242740400/in/gallery-26760199@N06-72157635300877547/">kmanohar/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<p>Our study provides evidence that the presence of humans not only changes the way top carnivores behave, but also indirectly impacts other species. Pumas that are afraid of humans but still hunt in residential areas alter their relationship with deer, their primary prey. Greater pressure on deer could possibly provide more food for scavengers or reduce deer browsing near developed areas. </p>
<p>Our work provides just one example of the cascading effects that human disturbance can cause in wild ecosystems. Human presence can fundamentally alter the ways in which species interact, which changes the function and composition of the animal community. By considering how humans impact the behavior of important species, we can develop conservation solutions that preserve entire functioning ecosystems.</p><img src="https://counter.theconversation.com/content/49728/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Justine Smith receives funding from the National Science Foundation, The Gordon and Betty Moore Foundation, The Nature Conservancy, Midpeninsula Regional Open Space District, UC Santa Cruz and the Felidae Conservation Fund.</span></em></p>Many Americans move to rural areas to live near nature. But the mere presence of humans changes wildlife behavior in ways that may have ripple effects.Justine Smith, Ph.D. Candidate in Conservation Biology, University of California, Santa CruzLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/464512015-10-13T10:46:18Z2015-10-13T10:46:18ZWhy more scientists are needed in the public square<figure><img src="https://images.theconversation.com/files/97300/original/image-20151005-28772-1ti19jn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">UCSF neuroscience grad student Sama Ahmed, whose three-minute talk on 'how to know your species' won first place at the campuswide contest, will compete for the Grad Slam championship in Oakland May 4. </span> <span class="attribution"><a class="source" href="http://www.universityofcalifornia.edu/news/uc-grad-slam-tests-scholars-communication-skills">Susan Merrell/UCSF</a>, <span class="license">Author provided</span></span></figcaption></figure><p>In this presidential election season, one thing is certain: candidates will rarely – if ever – be asked what they would do to keep this nation at the forefront of science and innovation.</p>
<p>That’s a shame.</p>
<p>The public dialogue about science is perhaps the most vital and most fraught national conversation not taking place in our country, and the ramifications are profound.</p>
<p>Ultimately, the way we address science and innovation will determine what our children learn in school, what college graduates bring to the larger world, how public lands and natural resources are cared for and whether people receive adequate health care. And the list goes on.</p>
<p>As the president of one of our country’s leading research university systems, I believe it is now incumbent on the academic community to ensure that the work and voices of researchers are front and center in the public square.</p>
<h2>Calling all scientists</h2>
<p>When the voices of scientists are not heard in the dialogue, there is a price to pay.</p>
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<span class="caption">A grateful public.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Salk_Thank_You.jpg">March of Dimes Birth Defects Foundation</a></span>
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<p>Just think how many thousands more victims, mostly children, would have suffered needlessly if Jonas Salk had not broken new ground when he went public with his discovery of his polio vaccine back in the 1950s.</p>
<p>As Stanford University’s Charlotte DeCroes Jacobs made clear in her recent excellent biography, <a href="https://global.oup.com/academic/product/jonas-salk-9780199334414?cc=us&lang=en&">Jonas Salk, A Life</a>, the fanfare brought Salk the everlasting disdain of some of his scientific colleagues, but it proved to serve the greater public good.</p>
<p>It is important that scientists be seen as regular people asking and answering important questions.</p>
<p>Our country needs more scientists who are willing and able to step out in the public arena and to weigh in, clearly and strongly – such as atmospheric physicist <a href="http://www-ramanathan.ucsd.edu/about/">Veerabhadran Ramanathan</a> of UC San Diego, who discovered the greenhouse effect of halocarbons in 1975. </p>
<p>Dr Ramanathan is a member of the Pontifical Academy of Sciences that <a href="http://www.sandiegouniontribune.com/news/2015/jun/18/pope-francis-UCSD/">influenced Pope Francis </a>to speak out on global climate change.</p>
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<p>We need more scientists who can explain what they are doing in language that is compelling and understandable to the public – for example, astrophysicist and Hayden Planetarium Director<a href="http://www.haydenplanetarium.org/tyson/"> Neil deGrasse Tyson</a>, whose use of television and social media earned him the <a href="http://www.nasonline.org/programs/awards/?referrer=https://www.google.com/">US National Academy of Sciences Public Welfare medal</a> this year for “exciting the public about the wonders of science.”</p>
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<p>Those of us in the academic community who are not scientists should also be prepared to support public engagement by scientists, and to incorporate scientific knowledge into our public communications. </p>
<p>I know from conversations I have had with other higher education leaders that I am not the only one who believes this is important.</p>
<h2>Understanding mysteries of research</h2>
<p>Too many people in this country – and that includes some among our elected leadership – still do not understand how science works or why robust, long-range investments in research vitally matter.</p>
<p>The truth is in the numbers. In the 1960s, the United States devoted nearly 17% of discretionary spending to research and development, <a href="http://www.nsf.gov/statistics/nsb0803/start.htm?CFID=18451611&CFTOKEN=42234921&jsessionid=f030ea890c79923b21615c3b96b6155b134a">reaping decades of economic growth</a> from this sustained investment. By 2008, the figure had fallen into the single digits. This occurs at a time when the private sector has cut back on its research investment and other nations <a href="http://www.scienceprogress.org/wp-content/uploads/2011/02/SciProgResearchandDevelopment-101.pdf">have made significant gains </a>in their own research capabilities. </p>
<p>China, for example, <a>is projected to outspend</a> the United States in research within the next decade. East Asia as a whole already does. </p>
<p>At the University of California, we pride ourselves not only on the quality of our research, but also on its contribution to improving aspects of the world we live in.</p>
<p>It is <a href="http://ucanr.edu/delivers/">UC’s research</a>, for example, that has made California among the most robust agricultural regions of the world. </p>
<p>To hasten the development of science from the lab bench to the market place, UC is investing our own money in our own good ideas. </p>
<p>This past summer, we launched the first <a href="http://primeuc.org/">primeUC</a> competition, which will award US$300,000 to winning start-ups in the health sciences. And last year, our Board of Regents approved <a href="http://www.wsj.com/articles/university-of-california-approves-venture-capital-fund-to-back-its-own-startups-1411072435">the creation of a new $250 million fund</a>, designed to provide seed money for direct investment into student and faculty inventions. </p>
<p>It also is possible to have some fun in demonstrating the broad, societal significance of research.</p>
<h2>Introducing Grad Slam</h2>
<p>Last May, I had the opportunity to emcee the first-ever University of California system-wide Grad Slam.</p>
<p>The Grad Slam asked UC graduate students to take their years of academic toil and research, and present their work to an audience in just three minutes, free of jargon or technical lingo.</p>
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<p>Think of these presentations as TED talks on steroids or the ultimate in elevator speeches. Each of our 10 campuses held a local competition, and the finals took place at our system-wide headquarters in Oakland. Several of those finalists are featured on <a href="https://theconversation.com/us/topics/uc-grad-slam-2015">The Conversation’s website</a>.</p>
<p>While it was a fun event, the purpose was very serious.</p>
<p>Good, sound science depends on hypotheses, experiments and reasoned methodologies. It requires a willingness to ask new questions and try new approaches. It requires one to take risks and experience failures.</p>
<p>But good, sound science also requires clear explanation, succinct presentation and contextual understanding. Telling the story is half the battle, and Grad Slam is perfect practice.</p>
<h2>‘An eternal guide to truth’</h2>
<p>On the flip side, our country needs more politicians who understand science and recognize it as more than window dressing for photo ops at school science fairs or opportunities to come before the cameras in white lab coats.</p>
<p>Scientists, of course, should not lose their focus on conducting research in the lab or the field, sharing knowledge with their peers, and supervising the postdocs and graduate students who will serve as the scientists of tomorrow.</p>
<p>In today’s world, however, society will benefit from scientists who also are able to raise the profile of science in the public dialogue.</p>
<p>In the rim of the dome of the National Academy of Sciences, there is an inscription <a href="http://www.nasonline.org/about-nas/visiting-nas/nas-building/the-great-hall.html">that reads</a>:</p>
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<p>To science, pilot of industry, conqueror of disease, multiplier of the harvest, explorer of the universe, revealer of nature’s laws, eternal guide to truth.</p>
</blockquote>
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<span class="caption">The nation’s home of science in America.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:National_Academy_of_Sciences,_Washington,_D.C._07_-_2012.JPG">Another believer</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>This is a fine, noble and trenchant statement of what science is all about. It is a statement that must be made to come alive in the nation’s public conscience, and in the public and political narrative.</p>
<p>For more than 200 years, science and research have been the source of our country’s greatest strengths, and the promise of its bright future.</p>
<p>Now more than ever, it is incumbent on scientists to put their knowledge on the table, and for others in the academic community to support them in that endeavor.</p><img src="https://counter.theconversation.com/content/46451/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Janet Napolitano served in President Barack Obama’s cabinet as Secretary of Homeland Security.</span></em></p>The president of one of the country’s leading research university systems argues that the academic community has to make sure researchers and scientists engage with the general public.Janet Napolitano, President, University of California, Office of the PresidentLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/461252015-09-17T10:10:47Z2015-09-17T10:10:47ZNative shrubs: a simple fix for drought-stricken crops in Sub-Saharan Africa<figure><img src="https://images.theconversation.com/files/94204/original/image-20150908-4358-1c8f4mq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Sahel, the transition zone between the arid north of Africa and tropic south, has highly variable rainfall. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/cifor/5656407416/in/photolist-9BQyRN-9BMy3H-6b7QUd-sxyue5-ebQFay-fqhSAh-ea4h5v-9BMwhn-eedMaH-9BQwGN-ebQFdf-fqhMs1-aFUXuT-fq3NJV-irS4Vo-irMAd8-7AbbfW-t7mjpN-8gTYSE-8gTdH3-gjA8j6-gjA8VM-ejq8QW-ejq8Ph-sQaum6-rT9LDG-sxyBdA-sxyB1S-sQasdc-sxGntr-sQarVt-rTkQZT-sPXfz3-rT9Ld1-sPXffq-sxGmXX-sQarC4-sQatEg-sPXf79-rTkQyx-sxzYBC-rTkQgi-sxGmwB-sxyzJ3-sxyzKL-rTkPQ8-sPXeph-sMQtad-rT9JLJ-rT9JQG"> Center for International Forestry Research.</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>Variability is the only guarantee when it comes to the rainfall of the Sahel, the transitional zone between the parched Sahara Desert and the wetter savanna in the south. The rains often arrive late, and sometimes they barely come at all. </p>
<p>This can lead to devastating crop failures and famine in a region that relies heavily on the rain to grow most of its food. Over the centuries, farmers across the Sahel have adapted to the fickle rainfall by growing crops such as millet, sorghum, peanut, and cowpea, which are well suited to produce grain even during periods of drought stress. </p>
<p>Sometimes, however, the crops’ adaptation is not enough to protect them from extended droughts, and grain yields plummet due to lack of water. To confound the already dire problem, the population of the Sahel is growing and crop yields <a href="http://iopscience.iop.org/article/10.1088/1748-9326/9/9/094003/pdf">are not increasing in step</a>.</p>
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<img alt="" src="https://images.theconversation.com/files/94234/original/image-20150909-26423-au6za2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/94234/original/image-20150909-26423-au6za2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94234/original/image-20150909-26423-au6za2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94234/original/image-20150909-26423-au6za2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94234/original/image-20150909-26423-au6za2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94234/original/image-20150909-26423-au6za2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94234/original/image-20150909-26423-au6za2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Farmers preparing fields for planting in 2013.</span>
<span class="attribution"><span class="source">Teamrat A. Ghezzehei</span></span>
</figcaption>
</figure>
<p>In these nutrient-poor soils with low fertilizer input, the land is in desperate need of agriculture systems that can provide adequate yields and soil conservation with minimal inputs. </p>
<p>This research on soil hydrology in the Sahel is part of a <a href="http://www.oardc.ohio-state.edu/senegal-pire/t01_pageview2/PIRE_Team.htm">larger project</a> funded by the National Science Foundation investigating how traditional techniques practiced by some farmers can be adapted to further increase crop yields, even during times of drought stress. We found that planting food crops together with the native woody shrub <em>Guiera senegalensis</em> can improve crop growth with minimal costs. It’s a simple method that can be used not only in the Sahel but may be applicable in many other areas that are periodically inhospitable to agriculture. </p>
<h2>Drinking from the same straw</h2>
<p>In some other agroforestry systems where crops are grown in association with trees, the trees can outcompete the crops for water and <a href="http://www.researchgate.net/profile/Laura_German/publication/225720953_Social_and_environmental_trade-offs_in_tree_species_selection_a_methodology_for_identifying_niche_incompatibilities_in_agroforestry/links/00463517e843a3210d000000.pdf">reduce the growth and yield of the crops</a> nearby. </p>
<p>In our work, we investigated a process called hydraulic lift, also known as hydraulic redistribution, whereby the <em>G. senegalensis</em> shrubs pump water from deep in the soil up through their root systems during the night and deposit it in the dry upper soil layers when they are not actively photosynthesizing. Hydraulic lift has been seen in environments that undergo periodic drought spells and has been shown to increase the ability of shallow roots to take up nutrients and <a href="http://link.springer.com/article/10.1007%2FBF00378231#page-1">maintain higher levels of transpiration</a> and photosynthesis. The process of hydraulic lift in <em>G. Senegalensis</em> was first observed by Dr. Fred Kizito and his colleagues as part of a similar National Science Foundation project in 2003-2004. </p>
<p>Our hypothesis was that each day, nearby pearl millet crops take advantage of some of this water that is drawn up by the shrubs. To test the hypothesis of water transfer, we set up a field study in Senegal under the harsh Sahelian conditions. This work is part of an ongoing research study looking at the growth of crops in association with the shrubs during the rainy cropping season. In order to create the necessary dry conditions we used irrigation to manipulate the amount and timing of water delivered for this experiment. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/94235/original/image-20150909-21369-c40hj0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/94235/original/image-20150909-21369-c40hj0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94235/original/image-20150909-21369-c40hj0.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94235/original/image-20150909-21369-c40hj0.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94235/original/image-20150909-21369-c40hj0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94235/original/image-20150909-21369-c40hj0.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94235/original/image-20150909-21369-c40hj0.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Millet grown for hydraulic lift tracer study under irrigation midseason 2014 without shrubs (left) with shrubs (right).</span>
<span class="attribution"><span class="source">Nathaniel Bogie</span></span>
</figcaption>
</figure>
<p>We monitored the soil moisture by using soil moisture sensors. Once we observed the daily drying and nightly re-wetting of the soil that is characteristic of hydraulic lift, we began our study. </p>
<h2>Water pathway</h2>
<p>Hydraulic lift occurs when roots remove water from the upper soil layers during the day, causing the soil to dry out. Then with the wet soil deep down and dry soil near the surface, the water moves up through the plant along a gradient, just like sucking water through a straw. Once it gets to the upper soil layers, it is pulled into the dry soil surrounding the roots in the same way a dry sponge sucks up a spill on a countertop. Our hypothesis is that some of this water that is released from the roots is used by nearby millet plants.</p>
<p>To carry out the experiment we attached bottles of water that included a chemical tracer to the deep roots of the shrub. Then we collected aboveground samples of the shrub and crop stems growing nearby over a period of five days to see where the tracer water went. </p>
<p>We found evidence of the tracer in a shrub on the first day after injecting the water, and shortly thereafter we found it in a crop growing nearby. This finding strongly supports the idea that water moved up through the roots of the shrub and into the crop. The exact route from the shrub roots to the crop is a topic of further investigation, but we are confident that a pathway exists. This combination of hydraulic lift and water transfer between species has long been hypothesized but rarely seen. It has never been observed as a component of an agroforestry system with such profound effects on crop production.</p>
<p>Our team consisted of American, French and Senegalese professors and graduate students, researchers from multiple African countries, and local farmers hired as field technicians. We rented land from a farmer named Saliou Diouf who works closely with the researchers at the <a href="http://www.isra.sn/index.php/zone-du-bassin-arachidier">Senegalese Agricultural Research Institute</a>. Saliou and his sons gave us invaluable perspective on cultivating millet and managing the shrubs. With the proceeds from research activities on his land, Saliou’s family has been able to build a drip irrigation system and buy water from the communal well in the village to grow and maintain a thriving vegetable business.</p>
<h2>Power of native plants</h2>
<p>The amount of water transferred between plants appears to be quite small. However, the quantity of water deposited may be much less important than the location where it is released. </p>
<p>The small cylinder of soil that surrounds plant roots, called the rhizosphere, plays a crucial role in a plant’s growth. It is the gateway through which most of the necessary water and nutrients must pass to nourish the plant, and it harbors a high concentration of microbes that perform a wide variety of tasks. Therefore, maintaining the viability of the rhizosphere to perform its functions under water stress is extremely important, and this zone is precisely where hydraulic lift deposits water. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/94233/original/image-20150909-26432-83pp9q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/94233/original/image-20150909-26432-83pp9q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94233/original/image-20150909-26432-83pp9q.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94233/original/image-20150909-26432-83pp9q.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94233/original/image-20150909-26432-83pp9q.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94233/original/image-20150909-26432-83pp9q.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94233/original/image-20150909-26432-83pp9q.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Professor Ibrahima Diedhiou (second from right) from the Senegalese National Agriculture University (ENSA) discussing plans with research team.</span>
<span class="attribution"><span class="source">Teamrat A. Ghezzehei</span></span>
</figcaption>
</figure>
<p>In our tests, we observed the roots of the crops engulfing the shallow shrub roots and we speculate that may be related related to the uptake of water.</p>
<p><em>G. senegalensis</em> grows extensively throughout the Sahel. The management technique under investigation involves planting the shrubs at a density higher than their natural distribution on the landscape so that they can help promote crop growth in a number of ways. </p>
<p>The ways in which hydraulic lift can affect the structure and function of the soil microbial community are also being investigated by our interdisciplinary team with the <a href="http://www.oardc.ohio-state.edu/senegal-pire/t01_pageview2/PIRE_Team.htm">NSF Partnership for International Research and Education (PIRE) program</a>. In other species hydraulic redistribution has been observed to significantly <a href="http://www.pnas.org/content/110/47/18988.abstract">alter</a> the <a href="http://www.researchgate.net/publication/7887297_Direct_nocturnal_water_transfer_from_oaks_to_their_mycorrhizal_symbionts_during_severe_soil_drying._Oecologia">function</a> of the <a href="http://jxb.oxfordjournals.org/content/58/6/1473.full">microbial communities</a> as well. We are also looking at how the presence of the shrubs, along with their potentially higher rates of micro and mesofauna – small organisms that live in soil, can affect the structure and characteristics of the surrounding soil.</p>
<p>The technique may be applicable across wide swaths of the Sahel with minimal additional inputs of labor and money. As the world population is increasingly forced to cultivate arid and marginal lands, we must not forget to look at how native plants adapt to their surroundings and use this knowledge to optimize our own systems, especially in places with limited resources.</p><img src="https://counter.theconversation.com/content/46125/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nathaniel Bogie receives funding from The National Science Foundation and The University of California, Merced. </span></em></p>Field trials in Senegal show native shrubs can access deep-soil water and make it available to adjacent crops – a technique that could alleviate drought conditions in marginal lands around the world.Nathaniel Bogie, PhD Candidate in Environmental Systems, University of California, MercedLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/438942015-09-14T10:14:13Z2015-09-14T10:14:13ZStem cells could help mend a broken heart, but they’ve got to mature<figure><img src="https://images.theconversation.com/files/94437/original/image-20150910-27328-16adew0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Heart cells showing damage after a heart attack.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:MI_with_contraction_bands_very_high_mag.jpg">Nephron</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Heart disease is the <a href="http://www.cdc.gov/heartdisease/facts.htm">number one cause of death</a> in the US. The most common type is coronary heart disease, which occurs when there’s a buildup of plaque within the heart’s blood vessels. <a href="http://www.nhlbi.nih.gov/health/health-topics/topics/hdw/causes">Smoking, diabetes, obesity and high blood pressure</a> can all contribute. When there’s a complete blockage – a heart attack – a large portion of the heart muscle dies. The heart responds by creating scar tissue, eventually leading to heart failure – the heart muscle just can’t pump enough blood to the rest of the body.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/94438/original/image-20150910-27340-2zsjmz.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/94438/original/image-20150910-27340-2zsjmz.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/94438/original/image-20150910-27340-2zsjmz.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=479&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94438/original/image-20150910-27340-2zsjmz.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=479&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94438/original/image-20150910-27340-2zsjmz.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=479&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94438/original/image-20150910-27340-2zsjmz.PNG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=602&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94438/original/image-20150910-27340-2zsjmz.PNG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=602&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94438/original/image-20150910-27340-2zsjmz.PNG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=602&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Blood vessels are blocked with plaque in atherosclerosis.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Coronary_heart_disease-atherosclerosis.PNG">NIH: National Heart, Lung and Blood Institute</a></span>
</figcaption>
</figure>
<p>Currently, the only treatment options for damaged heart muscle are <a href="http://heartsurgery.templehealth.org/content/heart_failure_surgery_transplantation.htm">surgery</a>, if possible, and for the worst cases, a whole heart transplantation. But there’s a <a href="http://www.organdonor.gov/about/data.html">huge shortage of organs</a> for transplantation, and for this reason, we need to find new strategies to treat heart disease.</p>
<p><a href="http://stemcells.nih.gov/info/basics/pages/basics1.aspx">Stem cells</a> have great potential to fill this void. They’re a unique type of cell that starts out unspecialized but can multiply and turn into specialized cells of the adult body – for instance, brain cells or heart muscle cells, officially called cardiomyocytes.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/94560/original/image-20150911-1566-d4g9rs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/94560/original/image-20150911-1566-d4g9rs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/94560/original/image-20150911-1566-d4g9rs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94560/original/image-20150911-1566-d4g9rs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94560/original/image-20150911-1566-d4g9rs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94560/original/image-20150911-1566-d4g9rs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94560/original/image-20150911-1566-d4g9rs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94560/original/image-20150911-1566-d4g9rs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A colony of induced pluripotent stem cells under the microscope.</span>
<span class="attribution"><span class="source">Ashley Fong</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Stem cells may be useful in tissue engineering therapies; researchers <a href="http://dx.doi.org/10.1016/j.biomaterials.2013.12.052">build tissues from them in the lab</a> to transplant and replace damaged muscle. They could potentially be used in cellular therapies; researchers inject the heart cells into the heart and <a href="http://dx.doi.org/10.1038/nature13233">allow for regeneration</a>. Right now, one <a href="http://capricor.com/clinical-trials/caduceus/">ongoing clinical trial</a> injects a heart attack patient’s own heart stem cells back into the patient’s heart to decrease scar size and promote heart regeneration. In addition, stem cells can also be used as a drug-screening platform in order to find new drugs to treat heart disease.</p>
<p>These options rely on turning stem cells into heart muscle cells – but even once they differentiate, the <a href="http://doi.org/10.1089/scd.2012.0490">heart cells remain immature</a>. They’re not fully developed, having characteristics you’d find in a fetus, not an adult. To advance these possible therapies, we need ways to take these heart muscle cells one step further, to maturity. I’m studying how the heart’s natural environment affects that maturation process. I focus on how the extracellular matrix, or scaffold, of the heart affects maturation. The overall goal is to find a way to create from stem cells fully functioning, mature heart cells that can be safely and effectively used for transplantation therapies and drug screening applications.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/QrNOHKjA2q4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The author explains her research as part of the UC Grad Slam 2015 at 29:23.</span></figcaption>
</figure>
<h2>Adult cells to stem cells to immature heart cells</h2>
<p>There are <a href="http://stemcells.nih.gov/info/basics/pages/basics1.aspx">many kinds of naturally occurring stem cells</a>, but I work with a type that can be made from the adult body. For example, I can take your regular skin cell or blood cell and <a href="http://dx.doi.org/10.1016/j.cell.2007.11.019%20show">transform it in the lab</a> into a stem cell by using viruses to introduce stem cell genes into it. The official name for what I wind up with after three or four weeks is “induced pluripotent stem cells.”</p>
<p>This new stem cell has the unique ability to replicate and turn into almost any cell of the adult body. Since they can be made from a patient’s own cells, the induced pluripotent stem cells retain the patient’s specific genetic information. That’s a big benefit when transplanting the cells – there’s no need for immunosuppression to avoid rejection of the new tissue by the patient’s body. It also allows a patient’s specific disease to be modeled in the lab, in hopes of finding a customized drug or therapy for this individual’s particular disease. This situation is sometimes called a “clinical trial in a dish.”</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/94530/original/image-20150911-1572-7zb9to.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/94530/original/image-20150911-1572-7zb9to.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/94530/original/image-20150911-1572-7zb9to.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94530/original/image-20150911-1572-7zb9to.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94530/original/image-20150911-1572-7zb9to.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94530/original/image-20150911-1572-7zb9to.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94530/original/image-20150911-1572-7zb9to.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94530/original/image-20150911-1572-7zb9to.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The author feeding her cells in the lab.</span>
<span class="attribution"><span class="source">Kimberly Lim</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>After years of hard work, I was finally successful at manipulating the stem cells into heart muscle cells in the lab. I had to find the perfect stem cell line and protocol to use, which required lots of trial and error. It was very exciting to finally see the beating heart muscle cells in my petri dish!</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/AONaH_oi3wQ?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Immature cardiomyocytes beating spontaneously in a petri dish.</span></figcaption>
</figure>
<p>But the cells’ ability to beat on their own actually demonstrates that they’re immature, and thus shouldn’t be used in treatment and drug screening. They spontaneously beat inappropriately. They don’t have the proper machinery to contract with the necessary force. These actions could have dangerous consequences if we were to rely on immature cells in a patient’s heart. Mature cardiomyocytes beat in response to a signal from the heart’s pacemaker cells, avoiding the safety risk of arrhythmia. And mature cells are strong enough to pump blood throughout the body. </p>
<p>So I need to figure out how to mature these cells. </p>
<h2>Scaffold provides more than just structure</h2>
<p>Within heart tissue, a scaffold surrounds the cells and provides structural support. The tissue is like a brick wall; the bricks are the cells and the mortar is the scaffold of proteins that holds everything together. Just as crucially, in a healthy heart, the scaffold sends signals to the heart cells to behave a specific way that allows them to survive and function normally.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/94558/original/image-20150911-1544-1r1cux5.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/94558/original/image-20150911-1544-1r1cux5.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/94558/original/image-20150911-1544-1r1cux5.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94558/original/image-20150911-1544-1r1cux5.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94558/original/image-20150911-1544-1r1cux5.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94558/original/image-20150911-1544-1r1cux5.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94558/original/image-20150911-1544-1r1cux5.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94558/original/image-20150911-1544-1r1cux5.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cut-up pieces of cow heart with the cells removed, leaving behind the scaffold.</span>
<span class="attribution"><span class="source">Ashley Fong</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>I obtain the heart scaffold by extracting it from cow hearts. I use detergents to remove the heart cells, similar to how laundry detergent removes dirt from clothes. Once all the cells are removed, only the scaffold remains. It’s made up of a network of fibers consisting of collagen, fibrinogen, elastin and other types of extracellular matrix proteins. After a few more steps, I get the scaffold into the form of a 3D gel – now it has a texture similar to Jello, which I can shape.</p>
<p>When I put my human stem cell-derived heart muscle cell into the adult heart scaffold, it matures. The process works by increasing the amount of some important proteins, including those that handle calcium. That improves calcium signaling, which is essential for the cell to contract.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/94559/original/image-20150911-1569-7llxph.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/94559/original/image-20150911-1569-7llxph.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/94559/original/image-20150911-1569-7llxph.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94559/original/image-20150911-1569-7llxph.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94559/original/image-20150911-1569-7llxph.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94559/original/image-20150911-1569-7llxph.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94559/original/image-20150911-1569-7llxph.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94559/original/image-20150911-1569-7llxph.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The tissue scaffold with the heart muscle cells inside.</span>
<span class="attribution"><span class="source">Ashley Fong</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>I also discovered that the most maturation occurs when the cells are grown in a 3D scaffold, rather than a 2D scaffold in a traditional flat petri dish. This finding supports the idea that placing the cells in an environment more like their natural habitat can instruct them to develop and mature. We still don’t know how the scaffold actually issues its instructions to the cardiomyocytes to mature, but for now we’re glad it seems to work. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/94528/original/image-20150911-1572-1v86pow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/94528/original/image-20150911-1572-1v86pow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/94528/original/image-20150911-1572-1v86pow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=457&fit=crop&dpr=1 600w, https://images.theconversation.com/files/94528/original/image-20150911-1572-1v86pow.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=457&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/94528/original/image-20150911-1572-1v86pow.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=457&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/94528/original/image-20150911-1572-1v86pow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=574&fit=crop&dpr=1 754w, https://images.theconversation.com/files/94528/original/image-20150911-1572-1v86pow.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=574&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/94528/original/image-20150911-1572-1v86pow.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=574&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mature heart muscle cells glowing green with blue nuclei.</span>
<span class="attribution"><span class="source">Ashley Fong</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We’re another step closer to being able to use mature stem cell-derived cardiomyocytes in new advanced treatment options to cure heart disease. I’m working on just a small sliver of the type of research that’s needed to get stem cells ready to be used to treat diseases. Stem cell research gives patients and their families hope, but cures won’t happen overnight. Even when we’re not seeing immediate results, stem cell research needs continued support so we researchers can develop the cures we so desperately need.</p><img src="https://counter.theconversation.com/content/43894/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ashley Fong receives funding from the California Institute for Regenerative Medicine, National Science Foundation and National Institute for Health.</span></em></p>Stem cells hold great promise for treating heart disease. But it’s not so simple to get from stem cell to fully functioning adult heart cell, even in the lab.Ashley Fong, PhD Student in Molecular Biology & Biochemistry, University of California, IrvineLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/438912015-08-20T09:53:13Z2015-08-20T09:53:13ZTalking to Mars: new antenna design could aid interplanetary communication<figure><img src="https://images.theconversation.com/files/92449/original/image-20150819-10879-196hpry.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Jean Paul Santos with the finished 4x4 sub-array antenna assembly that may help rovers talk directly with Earth.</span> <span class="attribution"><a class="source" href="http://newsroom.ucla.edu/stories/ucla-engineering-grad-student-attempts-to-talk-his-way-to-the-top">Matthew Chin</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>When people think about antennas, they often picture old television sets with “rabbit ears” – two metal rods poking above the screen. Essentially, antennas are devices that allow the wireless transfer or reception of radio signals. They come in various sizes and shapes. For instance, it’s your cellphone’s antenna that allows you to stream videos, post a social media status, use GPS to find a restaurant and call a friend.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/91932/original/image-20150814-2579-cj9ou5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/91932/original/image-20150814-2579-cj9ou5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/91932/original/image-20150814-2579-cj9ou5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/91932/original/image-20150814-2579-cj9ou5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/91932/original/image-20150814-2579-cj9ou5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/91932/original/image-20150814-2579-cj9ou5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/91932/original/image-20150814-2579-cj9ou5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/91932/original/image-20150814-2579-cj9ou5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mars rovers need to transmit all their cool findings back to Earth somehow.</span>
<span class="attribution"><a class="source" href="http://mars.jpl.nasa.gov/mars2020/multimedia/images/?ImageID=3650">NASA/JPL-Caltech</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>This wireless technology opened the door to space exploration. Neil Armstrong’s voyage to the moon was possible because antennas allow communication between engineered space vehicles and Earth. It’s an antenna that allows the <a href="http://mars.jpl.nasa.gov/mer/technology/bb_telecommunications.html">Mars rovers to communicate</a> with Earth from millions of miles away. To gather valuable scientific data, rovers often take measurements, pictures and video, then send them back home via radio waves at high frequencies, through their antennas. </p>
<p>Currently, the Mars rovers primarily rely on what’s called indirect or relay communications. They send their data to a much larger satellite antenna, called the <a href="http://mars.nasa.gov/mro/">Mars Reconnaissance Orbiter</a>, which then sends it all on to Earth at high transmission rates. The frequencies of transmission are in X-band, near 8 GHz, which has a radio wavelength close to 1.5 inches.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/91934/original/image-20150814-2585-qv9dhu.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/91934/original/image-20150814-2585-qv9dhu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/91934/original/image-20150814-2585-qv9dhu.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=427&fit=crop&dpr=1 600w, https://images.theconversation.com/files/91934/original/image-20150814-2585-qv9dhu.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=427&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/91934/original/image-20150814-2585-qv9dhu.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=427&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/91934/original/image-20150814-2585-qv9dhu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=537&fit=crop&dpr=1 754w, https://images.theconversation.com/files/91934/original/image-20150814-2585-qv9dhu.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=537&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/91934/original/image-20150814-2585-qv9dhu.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=537&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">It would be nice to cut out the middleman in transmitting communication back and forth between Earth and Mars.</span>
<span class="attribution"><span class="source">Joshua Kovitz, Jean Paul Santos and Yahya Rahmat-Samii</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Our group here at the UCLA <a href="http://www.antlab.ee.ucla.edu/">Antenna Research, Analysis, and Measurement Laboratory</a> specializes in <a href="https://ieeetv.ieee.org/conference-highlights/from-maxwell-s-equations-to-modern-electromagnetics-and-antenna-engineering-marvels">designing advanced antenna systems</a>, including <a href="http://dx.doi.org/10.1109/MAP.2015.2414534">spacecraft antennas</a> for future space missions. Now, with help from engineers at NASA’s <a href="http://www.jpl.nasa.gov">Jet Propulsion Laboratory</a> (JPL), we’re working to create a small yet powerful antenna that could allow the Mars rover to communicate directly with Earth, potentially cutting out the middleman. </p>
<p>At the present time, the Mars rover can relay information to the Mars Reconnaissance Orbiter for just <a href="http://mars.nasa.gov/msl/mission/technology/technologiesofbroadbenefit/telecom/">15 minutes twice a day</a> due to orbit conditions. Allowing the Mars rover to connect directly with Earth could offer a big increase in communication time – much more data could be sent back and forth when the rover is in direct line-of-sight. A direct link would also be an advantage in the event that large satellite orbiters are no longer available.</p>
<p>The challenge is to create an upgraded link that can do the job but also fit on the next upcoming Mars rover mission, <a href="http://mars.nasa.gov/mars2020/mission/rover/">Mars2020</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/QrNOHKjA2q4?wmode=transparent&start=3200" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Author Jean Paul Santos presents the Mars Rover antenna concept at the University of California’s Grad Slam competition.</span></figcaption>
</figure>
<h2>Good signal strength over astronomical distances</h2>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/92418/original/image-20150819-10863-10ut25n.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92418/original/image-20150819-10863-10ut25n.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/92418/original/image-20150819-10863-10ut25n.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=768&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92418/original/image-20150819-10863-10ut25n.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=768&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92418/original/image-20150819-10863-10ut25n.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=768&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92418/original/image-20150819-10863-10ut25n.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=965&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92418/original/image-20150819-10863-10ut25n.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=965&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92418/original/image-20150819-10863-10ut25n.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=965&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Like a bigger bucket in the rain, a larger antenna will receive a stronger radio signal.</span>
<span class="attribution"><span class="source">Joshua Kovitz, Jean Paul Santos and Yahya Rahmat-Samii</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>We need to achieve good signal strength in the small space set aside on the rover for an antenna. The physics of radio waves tells us that the larger the antenna, the more power it can receive. Think of an antenna as like a bucket collecting rain. The larger the bucket’s opening, the more water it can catch at any given time. As long as the antenna is much bigger than the wavelength, it works the same way: the bigger it is, the more power it can receive or transmit. With more power, the data can be better extracted from the radio waves that carry pictures, video and commands. Extracting the data works similarly to modern television signals, with audio and video carried by radio waves. </p>
<p>For future Mars rovers, 40 cm x 40 cm x 5 cm is potentially the maximum volume that the antenna can occupy. With the available area set, our job as antenna engineers is to figure out the best and most efficient way to use all the space given to maximize the amount of power. </p>
<p>Other criteria for the antenna to work on a Mars 2020 rover include:</p>
<ul>
<li>must be lightweight</li>
<li>must run on the prospective power available for radio transmissions – about 100 Watts, the same amount used by a bright incandescent lightbulb </li>
</ul>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/92419/original/image-20150819-10873-cecndr.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92419/original/image-20150819-10873-cecndr.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/92419/original/image-20150819-10873-cecndr.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92419/original/image-20150819-10873-cecndr.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92419/original/image-20150819-10873-cecndr.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92419/original/image-20150819-10873-cecndr.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92419/original/image-20150819-10873-cecndr.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92419/original/image-20150819-10873-cecndr.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">To achieve good signal strength, a mechanical gimbal arm can line up the Mars rover and Earth’s antennas.</span>
<span class="attribution"><span class="source">NASA/JPL-Caltech</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<ul>
<li>must be aligned with the Earth’s antenna. A robotic supporting arm called a gimbal can mechanically position the antenna. The Curiosity mission used a <a href="http://mars.nasa.gov/msl/">similar gimbal</a> to steer its high-gain antenna. </li>
</ul>
<h2>Adding up antenna elements into one array</h2>
<p>The big idea is to combine many small antennas (often called antenna elements) to make an altogether larger antenna. You can think of this antenna concept as like an organ system. An individual organ, such as the heart, can operate in and of itself. It’s when it’s combined with other organs that it can maintain a human being.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/92451/original/image-20150819-10863-sjbmds.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92451/original/image-20150819-10863-sjbmds.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92451/original/image-20150819-10863-sjbmds.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92451/original/image-20150819-10863-sjbmds.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92451/original/image-20150819-10863-sjbmds.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92451/original/image-20150819-10863-sjbmds.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=519&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92451/original/image-20150819-10863-sjbmds.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=519&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92451/original/image-20150819-10863-sjbmds.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=519&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The key is to get a really good antenna element that can join forces in an array. Note the half-E shape of the single element.</span>
<span class="attribution"><span class="source">Joshua Kovitz, Jean Paul Santos and Yahya Rahmat-Samii</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Our antenna “organs” begin with a specialized geometry that looks like half of the letter “E.” We derived it from the <a href="http://dx.doi.org/10.1109/8.933489">original E-shaped</a> antenna design we’ve already had a lot of success with. This novel “half-E” shape allows the antenna to transmit and receive radio signals which are <a href="https://en.wikipedia.org/wiki/Circular_polarization">circularly polarized</a>. Basically that means the polarization of the radio waves can be oriented in a special configuration that helps reduce the effects of atmospheric gases and particles on the waves as they travel. It can also help to make sure a strong signal is maintained even if the rover itself or the antennas are moving.</p>
<p>When enough of these antenna elements – 256 in this case – are combined together just right into what antenna engineers call an <a href="http://dx.doi.org/10.1109/MAP.2015.2397154">array</a>, the whole can transmit and receive much greater power.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/92421/original/image-20150819-10834-4n1j83.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92421/original/image-20150819-10834-4n1j83.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92421/original/image-20150819-10834-4n1j83.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=288&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92421/original/image-20150819-10834-4n1j83.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=288&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92421/original/image-20150819-10834-4n1j83.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=288&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92421/original/image-20150819-10834-4n1j83.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=362&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92421/original/image-20150819-10834-4n1j83.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=362&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92421/original/image-20150819-10834-4n1j83.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=362&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The antenna assembly is compact enough to fit within the rover’s space limitations.</span>
<span class="attribution"><span class="source">Joshua Kovitz, Jean Paul Santos and Yahya Rahmat-Samii</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>The overall complete array should fit nicely within the required volume, whose maximum area is comparable to a standard 12-inch by 12-inch chessboard. It’s a compact way to pack the same antenna power into a much smaller space than if we relied on larger, bulkier dish antennas that have the added disadvantage of being harder to stow on the rover during flight.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/92422/original/image-20150819-10861-dobwgx.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92422/original/image-20150819-10861-dobwgx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/92422/original/image-20150819-10861-dobwgx.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92422/original/image-20150819-10861-dobwgx.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92422/original/image-20150819-10861-dobwgx.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92422/original/image-20150819-10861-dobwgx.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92422/original/image-20150819-10861-dobwgx.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92422/original/image-20150819-10861-dobwgx.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Santos and Kovitz soldering the antenna assembly.</span>
<span class="attribution"><span class="source">Jean Paul Santos</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Transforming a novel idea into a real prototype</h2>
<p>Of course, any exciting venture in engineering research worth its salt comes with an experimental demonstration. As a first step, we designed, built and tested one of the smaller 4-by-4 element sub-arrays. We used simulation software to first understand how the antenna would perform in real-life scenarios. We drew the antenna in a computer-aided drafting program, which included all the necessary materials such as metals, ceramics and wires.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/92423/original/image-20150819-10879-1eejixv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/92423/original/image-20150819-10879-1eejixv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/92423/original/image-20150819-10879-1eejixv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/92423/original/image-20150819-10879-1eejixv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/92423/original/image-20150819-10879-1eejixv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/92423/original/image-20150819-10879-1eejixv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/92423/original/image-20150819-10879-1eejixv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/92423/original/image-20150819-10879-1eejixv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Santos testing the antenna prototype’s characteristics in an anechoic (no echo) chamber.</span>
<span class="attribution"><span class="source">Joshua Kovitz</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>After much fine-tuning and verifying that the antenna meets the JPL requirements mentioned above, we began physically constructing it. And it took us several attempts. We started by taking a couple of pieces of lightweight ceramic coated with metal and used photolithography and chemical etching to create the specialized antenna geometry. Since this antenna is several layers, we had to solder them all together. When we tested the antenna’s actual performance, we were gratified to see our prototype behaved the way our simulations predicted!</p>
<p>With a successful prototyping of the 4-by-4 element sub-array, the next step would be to prototype the full-scale 16-by-16 element antenna. Ultimately, we’d like to test it on the Mars rover system itself at a NASA test site here on Earth. We hope that with this design, JPL can potentially augment its communication system so the rover can successfully call home directly.</p><img src="https://counter.theconversation.com/content/43891/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jean Paul Santos received funding for the research described in this article from the Jet Propulsion Laboratory.</span></em></p><p class="fine-print"><em><span>Joshua M. Kovitz received funding for the research described in this article from the Jet Propulsion Laboratory.</span></em></p><p class="fine-print"><em><span>Yahya Rahmat-Samii received funding for the research described in this article from the Jet Propulsion Laboratory.</span></em></p>New research provides a compact but powerful way for Mars rovers to communicate directly with Earth via an array of smaller antenna elements, bypassing the need for an intermediary.Jean Paul Santos, PhD Student in Electrical Engineering, University of California, Los AngelesJoshua M Kovitz, PhD student in Electrical Engineering, University of California, Los AngelesYahya Rahmat-Samii, Professor of Electrical Engineering/Electromagnetics, University of California, Los AngelesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/439582015-07-27T10:59:31Z2015-07-27T10:59:31ZRenaissance on the bayou: the revival of a lost language<figure><img src="https://images.theconversation.com/files/89723/original/image-20150726-8461-wmwqvo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Members of the Chitimacha language team (from left to right) Sam Boutte, Kim Walden and Rachel Vilcan use the new language software for the first time.</span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>In the summer of 1930, at the dawn of the Great Depression, a 21-year-old linguist named <a href="http://www.jstor.org/stable/411975">Morris Swadesh</a> set out for Louisiana to record the area’s Native American languages, which were disappearing rapidly.</p>
<p>Morris and his peers were in a race against time to document them, and in the small town of Charenton on the Bayou Teche, he encountered Benjamin Paul and Delphine Ducloux, members of a small tribe called Chitimacha – and the last two speakers of their language.</p>
<p>But today, if you visited the <a href="http://chitimacha.gov/">Chitimacha reservation</a>, you’d never know that their language went unspoken for half a century.</p>
<p>Over the past several decades, <a href="http://www.berkeley.edu/news/media/releases/2008/06/06_breath.shtml">many Native American tribes</a> have participated in what has become <a href="http://sils2014.hawaii-conference.com/">a robust language revitalization movement</a>. As their populations of fluent speakers dwindle and age, tribes want to ensure that their heritage languages are passed on to the next generation – before it’s too late. </p>
<p>But because the Chitimacha tribe had no living speakers for a number of decades, it made the challenge that much greater. In the end, the story of the language’s decline, loss and rebirth is a remarkable example of cultural survival.</p>
<h2>Why document a language?</h2>
<p>Unlike some other cultural legacies, languages leave no trace in the archaeological record. There’s often no trace in the written record, either. </p>
<p><a href="http://www.jstor.org/stable/416368">Only a small portion</a> of the world’s estimated <a href="http://www.ethnologue.com/statistics">7,000 languages</a> are well-documented in places like dictionaries and grammar books. Those that are least well-documented are the most endangered. </p>
<p>Many dead or dying languages contain exotic features of verbal and written communication. Chitimacha, for example, doesn’t use a word “be” in phrases like “she is reading.” Instead, speakers must use a verb of position, such as “she sits reading” or “she stands reading.” These are things that <a href="http://www.jstor.org/stable/10.1086/431525">challenge linguists’ understanding</a> of how language works. </p>
<p>By working with Ben and Delphine, Morris was trying to capture a small piece of that linguistic diversity before it vanished.</p>
<p><audio preload="metadata" controls="controls" data-duration="120" data-image="" data-title="Wax cylinder recording of Ben Paul, c 1930." data-size="1926272" data-source="" data-source-url="" data-license="" data-license-url="">
<source src="https://cdn.theconversation.com/audio/174/ben-paul-recording-rs-cleanup.mp3" type="audio/mpeg">
</audio>
<div class="audio-player-caption">
Wax cylinder recording of Ben Paul, c 1930.
</div></p>
<p>One day, with Morris sitting on Ben’s porch dutifully scribbling down his every word in a composition notebook, Ben finished a story (a riveting tale of how the Chitimacha first acquired fire by stealing it from a mythical old blind man in the west). He then went on to tell Morris: </p>
<blockquote>
<p>There were very many stories about the west. I believe I am doing well. I have not forgotten everything yet. When I die, you will not hear that sort of thing again. I am the only one here who knows the stories. </p>
</blockquote>
<p>Ben passed away three years later, and Delphine not long thereafter. After their deaths, it seemed the Chitimacha language was doomed to silence.</p>
<h2>Why do languages die?</h2>
<p>How does a language come to have only two speakers? Why have so many Native American languages become endangered? The causes are manifold, but there are two main ones: sharp reductions in the population of the community that speaks the language, and interruptions in the traditional means of transferring the language from one generation to the next.</p>
<p>In the past, the former caused the most damage. Native American peoples were decimated by European diseases and subject to outright warfare. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/89687/original/image-20150724-8478-w3cvj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/89687/original/image-20150724-8478-w3cvj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=927&fit=crop&dpr=1 600w, https://images.theconversation.com/files/89687/original/image-20150724-8478-w3cvj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=927&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/89687/original/image-20150724-8478-w3cvj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=927&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/89687/original/image-20150724-8478-w3cvj6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1164&fit=crop&dpr=1 754w, https://images.theconversation.com/files/89687/original/image-20150724-8478-w3cvj6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1164&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/89687/original/image-20150724-8478-w3cvj6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1164&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A portrait of two Chitimacha by French-born painter François Bernard (1870).</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Two-Chitimacha-Indians_F_Bernard.jpg">Wikimedia Commons</a></span>
</figcaption>
</figure>
<p>Prior to European contact, the Chitimacha were lords of the bayou, with a territory stretching from Vermillion Bay in the west to present-day New Orleans in the east. They were expert canoe-makers and wielded extensive knowledge of the region’s labyrinthian network of waterways. </p>
<p>But by the time the French arrived in present-day Louisiana in 1699, the tribe’s numbers had <a href="http://www.amazon.com/Historic-Indian-Tribes-Louisiana-Present-ebook/dp/B00B02ASTK/ref=sr_1_1_twi_2_kin?ie=UTF8&qid=1435809417&sr=8-1&keywords=historic+indian+tribes+of+louisiana">dwindled to around 4,000</a>, their communities gutted by European diseases that spread faster than the Europeans themselves. </p>
<p>After a protracted war with the French, they retreated deep into the bayou, where the their reservation at Charenton sits today. The 1910 census recorded <a href="http://www.amazon.com/The-Indians-Southeastern-United-States/dp/087474895X">just 69 people</a> living there.</p>
<p>Only later did the second cause of language decline occur, when children on the reservation were sent to the infamous Carlisle Indian School in Pennsylvania, which interrupted the transmission of the language to the next generation. </p>
<p>Ben and Delphine, born in the latter half of the 1800s, were part of the last generation to learn the language at home. Eventually their parents and many of their peers passed away, leaving them as the last two speakers of the language.</p>
<h2>Renaissance on the bayou</h2>
<p>Ben probably never imagined that the efforts of him and Delphine would spark the tribe’s linguistic renaissance, awakening their language from 60 years of silence. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/89695/original/image-20150724-8478-b1snn2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/89695/original/image-20150724-8478-b1snn2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=785&fit=crop&dpr=1 600w, https://images.theconversation.com/files/89695/original/image-20150724-8478-b1snn2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=785&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/89695/original/image-20150724-8478-b1snn2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=785&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/89695/original/image-20150724-8478-b1snn2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=986&fit=crop&dpr=1 754w, https://images.theconversation.com/files/89695/original/image-20150724-8478-b1snn2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=986&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/89695/original/image-20150724-8478-b1snn2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=986&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Delphine Ducloux was one of the two last speakers of the Chitimacha language, prior to its revival.</span>
<span class="attribution"><a class="source" href="http://www.knowla.org/image/2440/&view=summary">State Library of Louisiana</a></span>
</figcaption>
</figure>
<p>In the early 1990s, cultural director for the tribe Kim Walden received a call from the <a href="http://www.amphilsoc.org/library">American Philosophical Society Library</a> informing her that they had all of <a href="http://www.amphilsoc.org/collections/view?docId=ead/Mss.497.3.B63c-ead.xml;query=chitimacha;brand=default#2">Morris’ notebooks, and even his drafts for a grammar manual and dictionary</a>, which totaled hundreds of pages in all. Thus began the herculean effort to revive the language.</p>
<p>The tribe put together a small-but-dedicated team of language experts, who set out to learn their language as quickly as possible. They began to produce storybooks based on Ben and Delphine’s stories, and word lists from the dictionary manuscript. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/E8bdYBA9VH8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The Chitimacha language: related to no other language in the world.</span></figcaption>
</figure>
<p>In 2008, the tribe partnered with the software company Rosetta Stone on a two-year project to create computer software for learning the language, which today every registered tribal member has a copy of. <a href="https://youtu.be/QrNOHKjA2q4?t=46m50s">This is where I came in</a>, serving as editor and linguist consultant for the project, a monumental collaborative effort involving thousands of hours of translating, editing, recording and photographing. We’re now hard at work finishing a complete dictionary and learner’s reference grammar for the language.</p>
<p>Today, if you stroll through the reservation’s school, you’ll hear kids speaking Chitimacha in language classes, or using it with their friends in the hall. At home they practice with the Chitimacha version of Rosetta Stone, and this past year the tribe even launched a preschool immersion program. </p>
<p>The kids even make up slang that baffles adult ears, a sure sign that the language is doing well – and hopefully will continue to thrive, into the next generation and beyond. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/QrNOHKjA2q4?wmode=transparent&start=2818" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Author Danny Hieber presents the story of the Chitimacha language at the University of California’s Grad Slam competition.</span></figcaption>
</figure><img src="https://counter.theconversation.com/content/43958/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel W. Hieber worked as part of Rosetta Stone's Endangered Language Program from 2008-2011. His current research is funded by a Graduate Research Fellowship from the National Science Foundation.</span></em></p>In the face of war, disease and outside cultural pressures, the Chitimacha language has survived – and now thrives.Daniel W. Hieber, PhD Candidate in Linguistics, University of California, Santa BarbaraLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/438282015-07-21T10:18:47Z2015-07-21T10:18:47ZLow-cost sensors track CO2 where it counts<figure><img src="https://images.theconversation.com/files/88483/original/image-20150715-17796-laxpdm.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A sensor monitors carbon dioxide from the rooftop of the SF Exploratorium.</span> <span class="attribution"><span class="source">Alexis Shusterman</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Earlier this summer, climate change was once again thrust into the global limelight, this time by an unlikely source – the pope. In his 184-page <a href="http://w2.vatican.va/content/francesco/en/encyclicals/documents/papa-francesco_20150524_enciclica-laudato-si.html">On Care for Our Common Home</a>, Pope Francis warned:</p>
<p><em>“A very solid scientific consensus indicates that we are presently witnessing a disturbing warming of the climatic system. […] A number of scientific studies indicate that most global warming in recent decades is due to the great concentration of greenhouse gases (carbon dioxide, methane, nitrogen oxides and others) released mainly as a result of human activity.”</em></p>
<p>Calling on his followers to take action at last, Pope Francis’ encyclical may represent a turning point in worldwide attitudes toward global warming. And with the <a href="http://www.cop21.gouv.fr/en">UN Climate Change Conference</a> hitting Paris this November, greenhouse gas regulation could soon become widespread.</p>
<p>The next question becomes: how will any regulations aiming to limit emissions be evaluated and enforced? Everyone wants reassurance that their neighboring countries are playing by the rules, but not all UN signatory nations can <a href="http://www.nap.edu/openbook.php?record_id=12883">afford</a> to provide <a href="http://dx.doi.org/10.1021/es3011282">detailed emissions reports</a> using the conventional techniques.</p>
<p><a href="http://oco.jpl.nasa.gov/">Orbiting satellites</a> can detect regional CO2 concentrations from space, but fall short when it comes to representing more intricate patterns. <a href="http://www.esrl.noaa.gov/gmd/ccgg/carbontracker/">Ground-level CO2 monitors</a> can quantify emissions at a specific location, but the favored technology is still too expensive for common use. And yet, effective <a href="http://www.nytimes.com/2012/08/29/business/energy-environment/obama-unveils-tighter-fuel-efficiency-standards.html">carbon regulation</a> needs to take place on hyperfine spatial and time scales – right down to the individual freeways and neighborhoods hiding in these methods’ blind spots.</p>
<p>To document the <a href="http://dx.doi.org/10.1016/j.atmosenv.2011.07.040">complex emission patterns</a> from urban CO2 sources, it would take a veritable army of sensors, packed into the atmospheric nooks and crannies of a city. </p>
<p>That’s where we come in.</p>
<h2>Distributed network</h2>
<p>I work on a project called BEACO₂N, which stands for the Berkeley Atmospheric CO2 Observation Network. BEACO₂N is a web of about 30 low-cost CO2-sensing monitors, or “nodes,” installed at two-kilometer (1.24-mile) intervals across the city of Oakland, California. </p>
<p>At this scale, it is the densest collection of CO2 monitoring instruments in the world.</p>
<p>The nodes utilize popular open-source <a href="https://www.arduino.cc/">microcontrollers</a> and <a href="https://www.raspberrypi.org/">computers</a> that transmit their measurements wirelessly using a simple smartphone data plan. The data are then made <a href="http://beacon.berkeley.edu">publicly available</a> in near-real time.</p>
<p>The <a href="http://www.vaisala.com/en/products/carbondioxide/Pages/gmp343.aspx">sensors</a> themselves measure changes in infrared light intensity to calculate CO2 concentrations in the air. Carbon dioxide absorbs infrared radiation, so more CO2 molecules floating across the light beam means that less light reaches the detector on the other side. It’s the same operating principle behind more expensive CO2 sensors, but using lower-grade lamps and detectors. This small compromise in accuracy means an entire BEACO₂N node can be assembled for about US$5,500. That’s 10–20 times less than conventional monitors, and cheap enough to be bought in bulk. And in this big-data era, providing more measurements at lower cost has broad appeal. </p>
<p>By blanketing the city with a tight “grid” of sensors, potential CO2 sources can be identified and quantified simply by <a href="http://dx.doi.org/10.5194/acp-15-1707-2015">comparing signals from adjacent nodes</a>. A higher CO2 level measured at the downwind node relative to its upwind neighbor indicates the presence of a CO2 emitter in between the two. This simple approach has already been used to assess the impact of the <a href="http://www.baybridgeinfo.org/closure">2013 Labor Day Weekend bridge closures</a> on Bay Area traffic emissions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/89050/original/image-20150720-12522-116j2zq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/89050/original/image-20150720-12522-116j2zq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/89050/original/image-20150720-12522-116j2zq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/89050/original/image-20150720-12522-116j2zq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/89050/original/image-20150720-12522-116j2zq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/89050/original/image-20150720-12522-116j2zq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/89050/original/image-20150720-12522-116j2zq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/89050/original/image-20150720-12522-116j2zq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Getting highly detailed data through a network of low-cost sensors.</span>
<span class="attribution"><span class="source">Alexis Shusterman</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>While individual nodes can perceive changes in CO2 as small as eight molecules out of a million, when used together, they are even more sensitive. Collectively, BEACO₂N’s high-resolution data set can drive <a href="http://dx.doi.org/10.1007/s00703-010-0068-x">complex atmospheric models</a> that zero in on still subtler emission phenomena, like the CO2 wafting from a congested freeway during rush hour or a drafty home in wintertime. </p>
<p>Such analyses will give local lawmakers the facts and figures to critically assess individual line items on California’s 73-part <a href="http://www.arb.ca.gov/cc/scopingplan/2013_update/first_update_climate_change_scoping_plan.pdf">climate action plan</a>. Communities can then focus resources on the most effective emissions-reducing initiatives.</p>
<h2>Not just CO2</h2>
<p>These days, BEACO₂N also serves as a pilot platform for testing <a href="http://www.shinyei.co.jp/stc/optical/main_dust_e.html">other low-cost sensing technologies</a>. </p>
<p>While CO2 generally isn’t harmful to breathe, it comes with co-emitted pollutants, like <a href="http://www.euro.who.int/__data/assets/pdf_file/0005/74732/E71922.pdf">carbon monoxide</a> or <a href="http://whqlibdoc.who.int/hq/2006/who_sde_phe_oeh_06.02_eng.pdf">soot particles</a>, that cause asthma and cardiovascular problems. As equipment for measuring these other species <a href="http://www.nytimes.com/2015/04/16/business/experimenting-at-home-with-air-quality-monitors.html">comes to market</a>, BEACO₂N could provide citizens with their own highly localized, real-time air <em>quality</em> data as well.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/89053/original/image-20150720-12543-1tpc8vj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/89053/original/image-20150720-12543-1tpc8vj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/89053/original/image-20150720-12543-1tpc8vj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/89053/original/image-20150720-12543-1tpc8vj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/89053/original/image-20150720-12543-1tpc8vj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/89053/original/image-20150720-12543-1tpc8vj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/89053/original/image-20150720-12543-1tpc8vj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/89053/original/image-20150720-12543-1tpc8vj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Inside a BEACO₂N node.</span>
<span class="attribution"><span class="source">Alexis Shusterman</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The first generation of measurements is already being analyzed by research scientists and high schoolers alike, and the data set continues to grow. Since its inception in 2012, the active network has expanded into San Francisco and Sonoma County, with interested parties as far away at Sydney, Australia.</p>
<p>That’s not to say that the BEACO₂N approach is without its own unique challenges. With cheaper equipment, you get what you pay for, namely: <a href="http://dx.doi.org/10.1016/j.atmosenv.2008.06.040">drift in the accuracy</a> of your data over time. Dust collects on lenses, mirrors get jostled out of alignment, and these small changes can gradually invalidate the original factory calibration.</p>
<p><a href="http://www.picarro.com/products_solutions/trace_gas_analyzers/co_co2_ch4_h2o">High-end instruments</a> combat this drift with bulky tanks of “reference” gases or pricey proprietary parts, both of which are incompatible with doing science on a budget. It can be just as expensive and time-consuming, however, to repeatedly cycle cheaper instruments back to the lab for recalibration. </p>
<p>To improve accuracy, the BEACO₂N team is currently investigating ways to remotely cross-reference veteran nodes against more recently calibrated ones. BEACO₂N may one day be able to use natural phenomena, such as large gusts of wind, to synchronize the signals across long distances. </p>
<p>By finding ways to do more with less, it is hoped that BEACO₂N can pave the way for similar strategies to be adopted by developing nations, or even by <a href="http://nerdsfornature.org/">curious citizen groups</a> here in the US. </p>
<p>Data produced affordably and accessibly means more knowledge for more people. And when it comes to managing emission reductions, knowledge is power.</p><img src="https://counter.theconversation.com/content/43828/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexis Shusterman is a graduate student working on the BEACO2N project at University of California, Berkeley. Her research is supported by the National Science Foundation and Bay Area Air Quality Management District in collaboration with Chabot Space and Science Center and the San Francisco Exploratorium.</span></em></p>Scientists build network of inexpensive air monitors to track emissions with fine-grained spatial detail – an alternative to satellites or pricey land-based CO2 monitors.Alexis Shusterman, PhD candidate in chemistry, University of California, BerkeleyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/436892015-07-09T10:20:30Z2015-07-09T10:20:30ZPrimed for battle: helping plants fight off pathogens by enhancing their immune systems<figure><img src="https://images.theconversation.com/files/87690/original/image-20150707-1306-rj5vyu.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A plant heavily colonized by a bacterial pathogen.</span> <span class="attribution"><span class="source">Jeannette Rapicavoli/UC Riverside</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><blockquote>
<p>Civilization as it is known today could not have evolved, nor can it survive, without an adequate food supply. – Norman Borlaug</p>
</blockquote>
<p>Most people have never heard of <a href="http://www.nobelprize.org/nobel_prizes/peace/laureates/1970/borlaug-bio.html">Norman Borlaug</a>. He is, thus far, the only agricultural scientist ever to win the Nobel Peace Prize. His work in the development of high-yielding and disease-resistant cereal crops saved more than one billion (yes, <em>billion</em>) people from starvation. </p>
<p>Though he uttered these words nearly 50 years ago, his message could not be more relevant today. We live in a world that is expected to exceed <a href="http://www.un.org/en/development/desa/news/population/un-report-world-population-projected-to-reach-9-6-billion-by-2050.html">nine billion people by around 2050</a>, and currently, some <a href="http://www.wfp.org/hunger/stats">800 million people</a> do not have enough food to live a healthy and active life. </p>
<p>The United Nations Food and Agriculture Organization projects that we need to <a href="http://www.fao.org/fileadmin/templates/wsfs/docs/Issues_papers/HLEF2050_Global_Agriculture.pdf">increase food production by at least 70%</a> to accommodate this surge in population growth. This is a daunting task, made even more difficult by the fact that nearly <a href="http://dx.doi.org/10.1111/j.1365-3059.2010.02411.x">20% of the global harvest is lost to plant diseases.</a> One of the most efficient ways to combat these diseases is through chemical control – the application of pesticides. However, pathogens can quickly develop resistance to pesticides, which can then require ever higher usage to maintain production. There are also <a href="http://dx.doi.org/10.1016/S0921-8009(01)00238-5">environmental and health concerns</a> associated with the application of potentially toxic chemicals to fields. </p>
<p>The demand is urgent for safer and more sustainable methods of crop protection. That’s where we, the plant pathologists, step in. A plant pathologist specializes in plant health in the same way a physician specializes in human health, and we work tirelessly to protect our food supply.</p>
<p>A novel area of research in the war against pathogens focuses on enhancing the plant’s natural immune system. If a plant can fight off an infection on its own, we can reduce the amount of pesticides needed. Similar to how children are vaccinated to protect against future diseases, plant pathologists are using the same methodology to “immunize” plants against pathogens, with the goal of strengthening their immune defenses against invaders. This method of priming plants’ immune systems could be a safe and effective way to save some of the global harvest currently lost to diseases. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/87533/original/image-20150706-994-yofhe7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/87533/original/image-20150706-994-yofhe7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/87533/original/image-20150706-994-yofhe7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/87533/original/image-20150706-994-yofhe7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/87533/original/image-20150706-994-yofhe7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/87533/original/image-20150706-994-yofhe7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/87533/original/image-20150706-994-yofhe7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/87533/original/image-20150706-994-yofhe7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A cassava specialist inspects a diseased crop in northeastern Thailand.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/ciat/4039130033">CIAT</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Understanding the plant immune system</h2>
<p>Plants are naturally exposed to a variety of pathogenic microbes, such as bacteria, fungi and viruses. In contrast with human beings, who have the ability to physically evade infections, plants are immobile. Therefore, every cell in the plant must defend itself against attack. Plants have a multi-tiered immune system that helps them fight off these microorganisms. It works in a manner very similar to the human immune system. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/87534/original/image-20150706-1015-176m2us.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/87534/original/image-20150706-1015-176m2us.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/87534/original/image-20150706-1015-176m2us.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/87534/original/image-20150706-1015-176m2us.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/87534/original/image-20150706-1015-176m2us.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/87534/original/image-20150706-1015-176m2us.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/87534/original/image-20150706-1015-176m2us.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/87534/original/image-20150706-1015-176m2us.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Plants learn to recognize bacteria like this one based on defining characteristics, or patterns, such as their flagella.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/ajc1/8498002874">AJ Cann</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Plants detect pathogens by recognizing microbial “patterns.” These are unique characteristics of the type of microbe (think bacterial flagella) that the plant has evolved to recognize as “non-self.” We can equate this capability to the recognition of antigens by the human body, which induces an immune response. Unfortunately, pathogens continuously evolve to evade recognition, typically by shielding or disguising these patterns. This ability allows them to colonize a plant’s cells before it can mount an effective immune response. </p>
<h2>Defense priming is like vaccination</h2>
<p>One of our major research goals is to harness these patterns to prime the <a href="http://dx.doi.org/10.1038/nature05286">plant immune system</a>, creating enhanced protection against pathogenic microbes, in lieu of traditional chemical control methods. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/87806/original/image-20150708-31604-15b9ber.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/87806/original/image-20150708-31604-15b9ber.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/87806/original/image-20150708-31604-15b9ber.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=901&fit=crop&dpr=1 600w, https://images.theconversation.com/files/87806/original/image-20150708-31604-15b9ber.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=901&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/87806/original/image-20150708-31604-15b9ber.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=901&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/87806/original/image-20150708-31604-15b9ber.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1132&fit=crop&dpr=1 754w, https://images.theconversation.com/files/87806/original/image-20150708-31604-15b9ber.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1132&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/87806/original/image-20150708-31604-15b9ber.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1132&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A vaccine protects against future disease.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/hdptcar/2267067180">hdptcar</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The principle of “<a href="http://dx.doi.org/10.1146/annurev-phyto-080614-120132">defense priming</a>” is very similar to how we develop vaccines to treat human diseases. A vaccine works by acting as a pathogen impostor. It tricks the immune system into thinking it’s being attacked, which stimulates defense responses, such as the production of antibodies. This creates a defense memory, allowing the immune system to remember a particular pathogen if the body encounters it in the future. It can then respond swiftly and robustly, thanks to its primed memory from the vaccine.</p>
<p>We can apply this same principle to a plant-pathogen relationship. For example, once we’ve identified a pathogen’s pattern of interest, we work to isolate and purify it. This step is like manufacturing the vaccine. We can then inoculate the plant with the purified pattern – for instance, by injecting it into the stem or leaves with a syringe. The goal is to stimulate the plant’s natural immune response, resulting in a faster and/or stronger defense response the next time the plant encounters that pathogen. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/QrNOHKjA2q4?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The author describing her research at the 2015 UC Grad Slam competition (at 35:15).</span></figcaption>
</figure>
<p>We’re basically ensuring that the plants are prepared for battle before the enemy attacks. <a href="http://dx.doi.org/10.1016/j.envexpbot.2012.02.013">Primed plants</a> display enhanced tolerance to infection, which is often characterized by fewer symptoms and reduced pathogen populations within the plant. Although primed plants haven’t yet been implemented on a large-scale basis in commercial agriculture, scientists are actively conducting research on the use of <a href="https://scholar.google.com/scholar?hl=en&q=priming+for+stress+resistance&btnG=&as_sdt=1%2C5&as_sdtp=">defense priming in both greenhouse and field</a> settings for protection against bacteria, viruses and fungi. </p>
<p>My own research focuses primarily on the use of defense priming for protection against a bacterial pathogen called <em>Xylella fastidiosa</em> that affects the multi-billion-dollar wine, table and raisin grape industries. It causes Pierce’s disease, which costs the state of California <a href="http://dx.doi.org/10.3733/ca.v068n01p20">over US $100 million annually</a> in crop loss expenses and efforts to treat it. There is currently no cure for the diseases caused by this plant pathogen, but our goal is to utilize defense priming to vanquish it.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/87823/original/image-20150708-31601-yr55fz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/87823/original/image-20150708-31601-yr55fz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/87823/original/image-20150708-31601-yr55fz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/87823/original/image-20150708-31601-yr55fz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/87823/original/image-20150708-31601-yr55fz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/87823/original/image-20150708-31601-yr55fz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/87823/original/image-20150708-31601-yr55fz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/87823/original/image-20150708-31601-yr55fz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Plants get sick too! Stem rust fungus on wheat.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Stem_rust_close_up.jpg">Yue Jin, Agricultural Research Service</a></span>
</figcaption>
</figure>
<h2>Potential in commercial agriculture</h2>
<p>In contrast with the human immune system, in which defense responses are specific to a particular germ, the effects of priming in plants are broad-spectrum, protecting the plant against a wide range of diseases and insect pests.</p>
<p>Another major benefit of defense priming is that there is little to no reduction in plant fitness – plants still grow and reproduce normally. This is a critical advantage in commercial agriculture, where success is contingent upon high yields.</p>
<p>Furthermore, the primed state is durable and can be maintained long after the initial stimulus. Current research has also shown that plants can pass on this defense memory to their progeny, providing <a href="http://dx.doi.org/10.1104/pp.111.191593">multigenerational protection</a> without any genetic modification.</p>
<p>Further research is needed to improve our understanding of the molecular mechanisms behind this phenomenon, but defense priming looks likely to be a valuable and promising tool in the future of sustainable agriculture.</p><img src="https://counter.theconversation.com/content/43689/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jeannette Rapicavoli receives funding through the California Department of Food and Agriculture Pierce’s Disease and Glassy-Winged Sharpshooter Program.</span></em></p>Vaccines aren’t just for animals anymore. Research shows priming plants with pathogen-derived compounds strengthens their immune systems and enhances protection against future attack.Jeannette Rapicavoli, PhD Candidate in Plant Pathology, University of California, RiversideLicensed as Creative Commons – attribution, no derivatives.