vendredi 9 mai 2008

Neil Young gives his name to a spider Canadian rocker Neil Young made headlines this week for appearing at the JavaOne conference and for releasing his musical archive on Blu-ray discs. But he was also honored by a East Carolina University (ECU) professor of biology, who named a newly discovered trapdoor spider Myrmekiaphila neilyoungi after the legendary rock star. According to the strict rules established by the International Commission on Zoological Nomenclature, the second word defining a new species must end in "i" if it's named after a person. So the researcher didn't break the naming scheme. It also was the case in 2005 when Cornell University named several beetles after Bush, Cheney and Rumsfeld. But read more... You can see above a male specimen of Myrmekiaphila neilyoungi living in Santa Rosa Co., Florida. (Credit: American Museum of Natural History [AMNH]) And here is a picture of a female specimen of Myrmekiaphila neilyoungi living in the same area. (Credit: AMNH) This new trapdoor spider species has been discovered in 2007 in Jefferson Co., Alabama, by Jason Bond, an ECU professor of biology. "'There are rather strict rules about how you name new species,' Bond said. 'As long as these rules are followed you can give a new species just about any name you please. With regards to Neil Young, I really enjoy his music and have had a great appreciation of him as an activist for peace and justice.'" Bond co-wrote a paper on this new spider with Norman I. Platnick, curator at the American Museum of Natural History in New York. This paper was published by American Museum Novitates under the name "Taxonomic review of the trapdoor spider genus Myrmekiaphila (Araneae: Mygalomorphae: Cyrtaucheniidae)." Here is a link to the abstract. "The mygalomorph spider genus Myrmekiaphila comprises 11 species known only from the southeastern United States. The type species, M. foliata Atkinson, is removed from the synonymy of M. fluviatilis (Hentz) and placed as a senior synonym of M. atkinsoni Simon. A neotype is designated for M. fluviatilis and males of the species are described for the first time. Aptostichus flavipes Petrunkevitch is transferred to Myrmekiaphila. Six new species are described: M. coreyi and M. minuta from Florida, M. neilyoungi from Alabama, M. jenkinsi from Tennessee and Kentucky, and M. millerae and M. howelli from Mississippi." For more information, here is a link to the full paper (PDF format, 32 pages, 8.97 MB). The illustrations above have been extracted from this document. Finally, if you're fascinated by spiders, you should read Platnick's World Spider Catalog. You'll learn that Myrmekiaphila neilyoungi belongs to the Cyrtaucheniidae family. Sources: East Carolina University news release, May 8, 2008; and various websites You'll find related stories by following the links below. Humor Music Nature Science 7:10:08 PM   Permalink

jeudi 8 mai 2008

NASA's lunar breathing system When six astronauts share a 15 cubic meters spacecraft for weeks, how is it possible to avoid to be bothered by your fellows sweating and breathing? I've already written about staying clean in space, but NASA is going further this time. Its scientists are testing a lunar breathing system. The CAMRAS system (short for 'Carbon-dioxide and Moisture Removal Amine Swing-bed') has been tested by 23 volunteers who stayed inside a test chamber from April 14 to May 1, 2008. It looks like that the results are satisfying NASA which could use it for its Orion crew capsule and its Altair lunar lander. But read more... You can see above how NASA "volunteers were bolted inside a test chamber and sweated for NASA scientists at Johnson Space Center in Houston to test a new system being developed for future space vehicles. The system, known as the carbon-dioxide and moisture removal amine swing-bed, or CAMRAS, is designed to make air breathable and the living space more comfortable by controlling carbon dioxide and humidity inside a crew capsule." (Credit: NASA) Here is a link to a larger version of this photo. And here is another link to a video of the CAMRAS test. Above is a picture of a prototype of the CAMRAS system. (Credit: NASA) Here are some explanations from another document from NASA, "Exploration Life Support" (PDF format, 3 pages, 823 KB), from which the above image has been extracted. "The Johnson Space Center (JSC) manages the efforts to develop a technology that is included in the Crew Exploration Vehicle (CEV) baseline design to address the needs to remove both carbon dioxide (CO2) and humidity from the cabin atmosphere. The packaging of the solid amine in each CAMRAS takes advantage of the exothermic heat of reaction during the adsorption phase by adding energy to the endothermic reaction during the desorption phase. The energy is transferred by thermally connecting layers that alternate between adsorbing and desorbing cycles." Now, let's look back at the latest NASA news release about CAMRAS. "This series of tests put volunteers inside a test chamber scaled to be the size of the Orion crew capsule, about 570 cubic feet. The volunteers, who were selected and grouped to replicate a typical crew, were asked to sleep, eat and exercise during test sessions that lasted from a few hours to overnight. 'The air smelled a little artificial, like on a plane, and it was a little crowded,' said Aaron Hetherington, one of the volunteers and a director for the test. 'But the air was fine; the temperature comfortable. My biggest observation is that it was unremarkable, which is good because that means the hardware was working.'" NASA has published several technical reports about the CAMRAS system, but you have to pay to read them. For more information, you can go to the NASA Technical Reports Server and search for "System for Carbon Dioxide and Humidity Control" (without the quotes). The latest report is named "Further Testing of an Amine-based Pressure-Swing System for Carbon Dioxide and Humidity Control" and is available -- today -- from this page. Here is the begoinning of the paper. "In a crewed spacecraft environment, atmospheric carbon dioxide (CO2) and moisture control are crucial. Hamilton Sundstrand has developed a stable and efficient amine-based CO2 and water vapor sorbent, SA9T, that is well suited for use in a spacecraft environment. The sorbent is efficiently packaged in pressure-swing regenerable beds that are thermally linked to improve removal efficiency and minimize vehicle thermal loads. Flows are all controlled with a single spool valve. This technology has been baselined for the new Orion spacecraft. However, more data was needed on the operational characteristics of the package in a simulated spacecraft environment. A unit was therefore tested with simulated metabolic loads in a closed chamber at Johnson Space Center during the last third of 2006." But more tests have been necessary. "The third phase of tests was performed during the spring and summer of 2007. Tests were run with a range of operating conditions, varying: cycle time, vacuum pressure (or purge gas flow rate), air flow rate, and crew activity levels. Results of this testing are presented and potential flight operational strategies discussed." When I was younger, I have dreamt to be an astronaut, probably like many of you. But when I read about the constraints imposed by space, I think it's better for me to live in Paris. Sources: NASA news release, May 7, 2008; and various websites You'll find related stories by following the links below. Chemistry Engineering NASA Space Technology 8:24:27 PM   Permalink

mercredi 7 mai 2008

UAVs will study Californian smog The California Energy Commission is funding a research effort named CAPPS, short for California AUAV Air Pollution Profiling Study. CAPPS will use autonomous unmanned aerial vehicles (AUAVs) to gather meteorological data as the aircraft fly through clouds over Southern California. The goal is to study smog and its consequences as well as better understand the sources of air pollution. The first flights started in April 2008 and data collection will continue until January 2009. But read more... You can see above technicians preparing a CAPPS autonomous unmanned aircraft for a flight at Edwards Air Force Base. (Credit: Scripps Institution of Oceanography) Here is a link to a larger version of this photo. This research work is being led at the Scripps Institution of Oceanography at UC San Diego by Professor V. (Ram) Ramanathan, who already used AUAVs over the Maldives in 2006. You can see above the UAV fleet at Hanimaadhoo Airport, Hanimaadhoo Island in the Maldives, during the Maldives Autonomous UAV Campaign (MAC) in March 2006 (Credit: V. Ramanathan). These UAVs are called Manta and are built by Tucson based Advanced Ceramics Research, Inc. (ACR). For more information about this earlier research project, you can read "Western Pacific Autonomous UAV Campaign" (PDF format, 28 pages, 14.46 MB). Now, let's go back to the CAPPS project. "In CAPPS, the Scripps team hopes to determine how much of Southern California's air pollution comes from Asia, Mexico and from regions north of California. Scientists routinely observe aerosol masses traveling across the Pacific Ocean to the West Coast but are still trying to understand the effects of that pollution. The imported smog is only one of several sources of atmospheric aerosols in Southern California, joining local auto and industrial emissions and smoke from wildfires. Researchers have seen evidence that this air pollution can mix with falling snow and accelerate its melt when sunlight hits and warms the 'dirty' snow in mountain watersheds." Here is a quote from Ramanathan. "Black carbon and ozone are two major contributors to global warming, next to carbon dioxide. We hope to document the vertical profiles of black carbon and ozone and their climate warming effects for the first time over California, and this data will likely help California reduce its global warming commitment." The CAPPS project will gather data throughout 2008 and until next year. But can their UAVs fly wherever the researchers want? "The aircraft will profile atmospheric conditions at altitudes ranging between 2,000 and 12,000 feet. Because of Federal Aviation Administration regulations that prohibit unmanned aircraft from flying in public airspace, the flight paths will be limited to military airspace, which is exempted from FAA rules. The researchers hope to conduct the flights at least once a month or as often as every two weeks. The Scripps team also hopes to gather data on a situational basis such as during wildfires." Finally, if you want to know how measurement instruments are miniaturized to fit in a UAV, please read this presentation about CAPPS (PDF format, 9 pages, 528 KB). Sources: Scripps Institution of Oceanography News, May 5, 2008; and various websites You'll find related stories by following the links below. Aerospace Engineering Environment Geosciences Robotics 7:04:04 PM   Permalink

mardi 6 mai 2008

A new robotic tasting device According to the latest American Chemical Society (ACS) Weekly PressPac, French researchers have developed an artificial mouth that chews apples like you and me. Here is a link to this PressPac, from which you'll be able to read a very short note titled 'Munch-o-matic: Scientists develop the artificial mouth.' The tasting device is able to reproduce the effects of chewing by analyzing a number of factors which are involved in the release of aromatic and flavor compounds in the mouth, such as the release of saliva or the rate of food breakdown. If this machine can chew food like us, it might pave the way for future machines which can learn to taste food and improve quality. But read more... You can see above a schematic representation of the artificial mouth. "The artificial mouth is composed of a sample container (600 mL), a notched plunger, and variable-speed motors to control precisely the speed of compression and rotation movements. The container is maintained at 37 °C by means of a laboratory thermostat (Bioblock Scientific) via an outer layer. The container is sealed with a cap maintained by a circlip." (Credit: Gaëlle Arvisenet and colleagues, via ACS). Hre is a link to a larger version of this diagram. This research work has been led by Gaëlle Arvisenet at the French ENITIAA school which trains engineers for the food industry sector. Unfortunately, Arvisenet has not her own research page on the University site. The ENITIAA research work is available online from the ACS's Journal of Agriculture and Food Chemistry under the name "Effect of Apple Particle State on the Release of Volatile Compounds in a New Artificial Mouth Device." It should appear in the printed version in the May 14, 2008 issue of the scientific paper. Here is a link to the abstract. "Varying the crushing parameters in a model mouth apparatus gave different crushed apple samples, which were compared to apples crushed in the human mouth by six people. An image analysis method was developed to measure the similarity between apple particles after crushing in the artificial mouth and in the human mouth. Thus, experimental conditions were determined that produced fruit in a state closest to that obtained after mastication in a human mouth. The influence of these different conditions on the quantity of released volatile compounds was then studied." The full paper is also currently available in an HTML version and as a PDF document (9 pages, 1.82 MB). Here is an excerpt from the introduction. "To be perceived while eating a food, aroma compounds must be released from the food matrix before being transported to the receptors. In solid foods, a succession of events takes place, which influence volatile release. When the food is crushed and mixed with saliva, its structure is modified and the diffusion of its volatiles from the resulting bolus to the headspace is affected. With mastication, the food surface area exposed to the air increases, and the food matrix is separated from the water it contained initially. These processes involve not only the composition and structure of foods but also the conditions in the mouth, that is, temperature, presence of saliva, rate at which food is broken down during chewing, and possible adsorption by the mouth mucosa. Moreover, the disruption of tissues can induce the enzymatic generation of volatiles. Two experimental approaches have been developed to study volatile release in the mouth." So what approach was used by the scientists? "In the present work, an artificial mouth was designed in which we studied apples as a model of real foodstuffs with a complex structure and chewy texture. Using a previous artificial mouth (26), we showed that the amounts of extracted volatile compounds were not the same when apples were crushed, cut into slices, or reduced to a puree state. It follows that to study the aroma compounds responsible for global aroma perception, it is necessary to reproduce the changes that the foodstuffs undergo in the human mouth. Our objectives were, first, to find artificial mastication settings that best reproduce human mastication and, second, to determine if artificial mastication conditions have an effect on the release of volatile compounds." Arvisenet said that "Our aim was not to reproduce human mouth conditions exactly, but to reproduce the result of mastication. Some control parameters of the artificial mouth were determined by comparison with in vivo mastication. Parameters that could not imitate exactly in vivo conditions were assigned different values, with an experimental plan. Fruit crushed in the artificial mouth were compared with fruit chewed in vivo by image texture analysis. Volatile compounds extracted in each experimental condition were analyzed. We did not compare volatile compounds released after in vitro and in vivo mastication in the present study." So what will happen next? "Now that a method to characterize apple state has been successfully applied, the next steps will concern the optimization of aroma release. To know which artificial mouth settings best mimic the human mouth, it will be necessary to compare the volatile profile obtained with volatiles released in vivo. The compounds responsible for the aroma of fresh apple may then be distinguished from those produced during the extraction. It can be stated that, coupled with more sensitive analysis conditions or with online analysis such as APCI-MS or PTR-MS, the present device would allow a real improvement in extraction from hard foods." Sources: American Chemical Society weekly news release, April 30, 2008; and various websites You'll find related stories by following the links below. Chemistry Engineering Food Nature Robotics Science 7:13:55 PM   Permalink

lundi 5 mai 2008

From fungus to fuel An international team of researchers led by some U.S. Department of Energy's research labs has decoded the genetic sequence of a fungus named Tricoderma reesei. The team has found how this organism breaks down plant fibers into simple sugars and how to use this fungus to produce fuel. 'The finding could unlock possibilities for industrial processes that can more efficiently and cost effectively convert corn, switch grass and even cellulose-based municipal waste into ethanol.' But read more... You can see above a photo showing "a microscope image of the fungus Tricoderma reesei growth filaments. In the image, proteins in fungal cells are stained red, while chitin, a component of the cell walls, is stained blue." (Credit: Mari Valkonen, VTT Technical Research Center, Finland) Here are two links to a larger version of this photo and to the Wikipedia page about Trichoderma reesei. Here are some of the interesting discoveries of the research team. "The organism uses enzymes it creates to break down human-indigestible fibers of plants into the simplest form of sugar, known as a monosaccharide. The fungus then digests the sugars as food. Researchers decoded the genetic sequence of T. reesei in an attempt to discover why the deep green fungus was so darned good at digesting plant cells. The sequence results were somewhat surprising. Contrary to what one might predict about the gene content of a fungus that can eat holes in tents, T. reesei had fewer genes dedicated to the production of cellulose-eating enzymes than its counterparts." So how this fungus could be used to produce fuel? "'We were aware of T. reesei's reputation as producer of massive quantities of degrading enzymes, however we were surprised by how few enzyme types it produces, which suggested to us that its protein secretion system is exceptionally efficient,' said Los Alamos bioscientist Diego Martinez (also at the University of New Mexico), the study's lead author. [...] On an industrial scale, T. reesei could be employed to secrete enzymes that can be purified and added into an aqueous mixture of cellulose pulp and other materials to produce sugar. The sugar can then be fermented by yeast to produce ethanol. This research work is available online from Nature Biotechnology as an advance online publication. The title of the paper is "Genome sequencing and analysis of the biomass-degrading fungus Trichoderma reesei (syn. Hypocrea jecorina)" (May 4, 2008). Here is a link to the abstract. "Trichoderma reesei is the main industrial source of cellulases and hemicellulases used to depolymerize biomass to simple sugars that are converted to chemical intermediates and biofuels, such as ethanol. [...] Our analysis, coupled with the genome sequence data, provides a roadmap for constructing enhanced T. reesei strains for industrial applications such as biofuel production." It is interesting to note that this paper has been co-signed by 45 researchers from six countries, Austria, Chile, Finland, France, Spain and the U.S. If one of the researchers reads this post, please drop me a note to tell me how you collectively wrote this article. Did you use meetings, phone calls, e-mail or instant messaging exchanges? Or did you use a common blog or a Wiki? Thank you for your help. Sources: Los Alamos National Laboratory news release, May 4, 2008; and various websites You'll find related stories by following the links below. Chemistry Energy Environment Genetics Nature Science 7:01:24 PM   Permalink

dimanche 4 mai 2008

Brain waves used for faster image sorting Computers are fast for many tasks, but humans are faster for identifying objects or people in images. But is it possible to combine the speed of a computer with the sensitivity of the human brain? According to a IEEE Spectrum Online article, 'A Brainy Approach to Image Sorting,' several teams at Honeywell, Teledyne Scientific and Imaging, and Columbia University think so. They're working on a Defense Advanced Research Projects Agency's program called 'Neurotechnology for Intelligence Analysts' (NIA). One of the teams said intelligence analysts can sort images six times faster than before. But there is a culprit: they'll need to carry for hours a 32-electrode EEG cap which detects their brain activity. But read more... The Defense Advanced Research Projects Agency (DARPA)'s program, Neurotechnology for Intelligence Analysts (NIA), in its third and final stage. At the end of this stage, one of the teams mentioned above will be selected. OGI Deniz Erdogmus, an assistant professor of computer science and engineering at the OGI School of Science & Engineering of the Oregon Health & Science University (OHSU) is working with the Honeywell team on the NIA project. You can see above some pictures used by Erdogmus in his lab to speed up sorting. (Credit: Unknown photographs, via IEEE Spectrum Online) According to Erdogmus, "it takes humans about 300 milliseconds to consciously recognize specific information in a picture -- an adult face among children, for example. It takes another 200 ms for the person to react physically, say, by pushing a button as an analyst would do. But even before a person is conscious of what he or she is seeing -- about 150 ms after being shown an image -- the electrical activity in the brain's visual cortex has already spiked. The activity is called an event related potential, or ERP." With these facts in mind, Erdogmus designed his experiments. "Six professional image analysts watched as aerial photographs flashed on a computer screen, more than five of them per second. The analysts were told to search the terrain for large targets, such as golf courses. Meanwhile, a 32-electrode EEG cap, plastered to the analysts' heads, detected brain activity that was then recorded in a separate computer. After the experiment, Erdogmus ran the recordings through a program that flagged any pictures whose appearance coincided with an ERP. While his analysis pulled out many false targets, it rarely missed a real one." The results look good, but Erdogmus's team is still facing several challenges. First, "the brain continues to respond electrically even after the image disappears, which makes it difficult to match signals with the pictures that evoked them." This can be solved by calibrating the system for each new user, but this might be expensive. Then, there are users' issues. "The question remains whether watching images in rapid sequence will tire analysts out faster and ultimately make them less efficient." And the analysts will have to have a conductive gel covering their heads and electrodes hooked to their heads for long times. This is not something I would like to do... Anyway, the research that Erdogmus is doing for DARPA is not widely available. Nevertheless, he co-authored a large number of papers. For example, during the 2006 Conference on Human Factors in Computing Systems (CHI '06), held in Montréal, Québec, Canada, he presented a paper named "Neurophysiologically driven image triage." Here is a link to the abstract. "Effective analysis of complex imagery is a vital aspect of important domains such as intelligence image analysis. As technological developments lower the cost of gathering and storing imagery, the cost of searching through large image sets for important information has been growing substantially. This paper demonstrates the feasibility of using neurophysiological signals associated with early perceptual processing to identify critical information within large image sets efficiently. Brain signals called evoked response potentials, detected in conjunction with rapid serial presentation of images, show promise as a human computer interaction modality for screening high volumes of imagery accurately and efficiently." He also presented a paper at the 3rd International IEEE/EMBS Conference on Neural Engineering held in Hawaii in May 2007 named "A Fusion Approach for Image Triage using Single Trial ERP Detection." Here is a link to the abstract. "This paper addresses the problem of conducting visual target search on a large set of images. We use electroencephalography to detect targets and apply a fusion approach combining neurophysiologic signals and overt physical responses to achieve high target detection accuracy. We conducted an experimental evaluation of the method using trained human experts to find target objects in broad area satellite images. Based on the fusion results, we applied spatial target likelihood maps to present the estimated target locations in the images. The results demonstrate the efficacy of the method on multiple subjects." Sources: Morgen E. Peck, IEEE Spectrum Online, April 2008; and various websites You'll find related stories by following the links below. Artificial Intelligence Engineering Medicine Military Applications Security Vision and Visualization 6:59:27 PM   Permalink

samedi 3 mai 2008

Extracting the structure of networks Networks are used to represent the structure of complex systems, including the Internet or social networks, but often these descriptions are biased or incomplete. Now, researchers at the Santa Fe Institute (SFI) have shown that it's possible to extract automatically the hierarchical structure of networks. The researchers say their results 'suggest that hierarchy is a central organizing principle of complex networks, capable of offering insight into many network phenomena.' They also think that their algorithms can be applied to almost every kind of networks, from biochemical networks (protein interaction networks, metabolic networks or genetic regulatory networks) to communities in social networks. But read more... You can see on the left "a hierarchical network with structure on many scales, and the corresponding hierarchical random graph. Each internal node r of the dendrogram is associated with a probability pr that a pair of vertices in the left and right subtrees of that node are connected. (The shades of the internal nodes in the figure represent the probabilities.) (Credit: SFI) Here is a link to a larger version of this figure. This technique has been developed by three Santa Fe Institute (SFI) researchers, Aaron Clauset, a post-doctoral fellow at SFI, Cris Moore, who is also an associate professor of computer science at the University of New Mexico, and Mark Newman, a professor of physics at the University of Michigan. Here is an excerpt from the SFI news release about this work. "Unlike much previous work in this area, Clauset, Moore, and Newman propose a direct but flexible model of hierarchical structure, which they apply to networks using the tools of statistical physics and machine learning. To demonstrate the practical utility of their model, they analyze networks from three disparate fields: the metabolic network of the spirochete Treponema pallidum (the bacteria that causes syphilis), a network of associations between terrorists, and a food web of grassland species. Even when only half of the connections in these networks were shown to their algorithm, the researchers found that hierarchical structure can predict missing connections with an accuracy of up to 80 percent." You can see on the left an example of an "application of the hierarchical decomposition to the network of grassland species interactions: a, Consensus dendrogram reconstructed from the sampled hierarchical models: b, A visualization of the network in which the upper few levels of the consensus dendrogram are shown as boxes around species (plants, herbivores, parasitoids, hyperparasitoids and hyper-hyperparasitoids are shown as circles, boxes, down triangles, up triangles and diamonds, respectively)." (Credit: SFI) Here is a link to a larger version of this figure. This research work has been published in the May 1, 2008 of Nature (Volume 453, Number 7191). Here is a link to the Nature editor's summary, "Refining the network." "Networks are now a ubiquitous tool for representing the structure of complex systems, including the Internet, social networks, food webs, and protein and genetic networks. Unfortunately, the data describing these networks are in many cases incomplete or biased. A new study provides a general technique to divide network vertices into groups and sub-groups. Revealing such underlying hierarchies makes it possible to predict missing links from partial data with higher accuracy than previous methods." This issue of Nature carries two articles on this subject. The first one, from Sid Redner, of Boston University, is called "Networks: Teasing out the missing links" (Pages 47-48). Here is the abstract (Pages 47-48). "Focusing on the hierarchical structure inherent in social and biological networks might provide a smart way to find missing connections that are not revealed in the raw data -- which could be useful in a range of contexts." Here is another link to a 'beautiful' image showing assortative and disassortative networks. The SFI letter to Nature appears on pages 98-101 on the same issue under the title "Hierarchical structure and the prediction of missing links in networks." Here is an excerpt from the abstract. "Here we present a general technique for inferring hierarchical structure from network data and show that the existence of hierarchy can simultaneously explain and quantitatively reproduce many commonly observed topological properties of networks, such as right-skewed degree distributions, high clustering coefficients and short path lengths. We further show that knowledge of hierarchical structure can be used to predict missing connections in partly known networks with high accuracy, and for more general network structures than competing techniques. Taken together, our results suggest that hierarchy is a central organizing principle of complex networks, capable of offering insight into many network phenomena." For more information, here is a link to the full paper (PDF format, 21 pages, 287 KB). Sources: Santa Fe Institute (SFI) news release, May 1, 2008; and various websites You'll find related stories by following the links below. Internet Networking Physics Social Networks Software 7:35:22 PM   Permalink

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