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FactCheck.org. Genome-wide signatures of convergent evolution in echolocating mammals : Nature. Taxonomic coverage We collected new genome-wide sequence data from four bat species, selected from the two suborders and encompassing the paraphyly of echolocating bat lineages (see ref. 13). From the suborder Yinpterochiroptera we studied the non-echolocating Old World fruit bat Eidolon helvum (family Pteropodidae) and two laryngeal echolocating species, Megaderma lyra (Megadermatidae) and Rhinolophus ferrumequinum (Rhinolophidae). From the suborder Yangochiroptera we studied the laryngeal echolocating species Pteronotus parnellii (Mormoopidae) that has independently evolved constant frequency echolocation. Phylogenetic hypotheses tested To investigate the prevalence of convergent evolution at a genome-wide level associated with the independent evolution of echolocation in bats and cetaceans, we used a method that builds on maximum-likelihood phylogenetic reconstruction.

Sequencing and data set assembly CDS alignment Sets of genes associated with hearing and vision Analysis pipeline. OCEARCH Global Tracking Central. How chemistry works: Gorgeous vintage science diagrams from 1854. By Maria Popova Illustrated retro reactions from the father of Popular Science. Edward Livingston Youmans (1821-1887), best-remembered as the founder of Popular Science magazine, was one of history’s greatest science writers and editors.

Besides pioneering what Richard Feynman has termed “the role of scientific culture in modern society” with his journalistic endeavors, Youmans also authored a number of beautifully illustrated textbooks, including Chemical Atlas: Or, The Chemistry of Familiar Objects. Originally published in 1854, the book is in the public domain but is sadly long out of print. A digital version is available in multiple formats from The Internet Archive, and it has been reproduced in hard-copy, alas without the artwork.

Many of the individual illustrations are available as prints. (Click each image for the poster version.) Youmans writes in the introduction: Complement with some gorgeous vintage science ads, anatomical illustrations, and science infographics. The 20 big questions in science | Science | The Observer. 1 What is the universe made of? Astronomers face an embarrassing conundrum: they don't know what 95% of the universe is made of. Atoms, which form everything we see around us, only account for a measly 5%. Over the past 80 years it has become clear that the substantial remainder is comprised of two shadowy entities – dark matter and dark energy.

The former, first discovered in 1933, acts as an invisible glue, binding galaxies and galaxy clusters together. Unveiled in 1998, the latter is pushing the universe's expansion to ever greater speeds. Astronomers are closing in on the true identities of these unseen interlopers. 2 How did life begin? Four billion years ago, something started stirring in the primordial soup. 3 Are we alone in the universe? Perhaps not. 4 What makes us human? Just looking at your DNA won't tell you – the human genome is 99% identical to a chimpanzee's and, for that matter, 50% to a banana's. 5 What is consciousness? We're still not really sure. 6 Why do we dream? Fungus and bacteria play game theory to make biofuels. To ensure that biofuel production doesn't compete with material that could otherwise provide food, researchers have been trying to produce biofuels from cellulose, the tough polymer that gives wood its strength. Unfortunately, cellulose isn't easy to digest, and the organisms that can digest it are bad at using it to produce something we could burn in an engine.

To get around this, many researchers have attempted to create a single microbe that can do both—digest the cellulose and directly convert it to a usable fuel. So far, however, efforts to engineer all the pathways to digest haven't worked out as well as we might hope, so a team of researchers has decided to use a pair of organisms instead. And, by testing a variety of conditions, they found that their behavior was predictable based on game theory.

Cellulose is a polymer of the sugar glucose, which can readily be digested and used to power cellular processes. Are there species smaller than 1 mm? Finding the limits of speciation. Despite their small size, organisms smaller than a thousandth of a meter (1 mm) contribute greatly to biodiversity and ecosystem function. Unfortunately, categorizing small organisms—even defining those categories—is difficult. Do small organisms form discrete species? Advances in DNA sequencing, combined with large surveys of small organisms, suggest that they may not. The process of defining a species is a historical practice. They start by asking a biological question: are there circumstances where species formation breaks down? Modeling species Studying the relationship of organisms to one another and their environment helps define something as a “species.”

DNA sequencing technology is advancing at such a dizzying pace that biologists increasingly rely on mathematical models to understand complex systems. Do species form at all scales? For both ecological and genetic versions of the model, the higher the mutation rate or population size, the less likely it was for a species to form. First Animal to Survive in Space. Tardigrada. Tardigrades, Oursons d'eau Longs de 0,1 à un peu plus de 1 mm, les tardigrades sont des animaux extrêmophiles, c'est-à-dire qu'ils peuvent survivre dans des environnements extrêmement hostiles.

(températures de −272 à +150 °C et pressions jusqu'à 6 000 bar[6], milieu anhydrique ou exposé aux rayonnements ultraviolets ou X, vide spatial[7]). Privés d'eau et de nourriture, ils se replient en cryptobiose, ce qui signifie que les processus métaboliques observables sont considérablement réduits : le tardigrade est alors en état de stase jusqu'à réactivation de ses processus métaboliques (sortie de stase). La stase peut durer une trentaine d’années[8]. Description[modifier | modifier le code] Un tardigrade vu au microscope.

Tous les tardigrades adultes de la même espèce ont le même nombre de cellules (Eutélie). Physiologie[modifier | modifier le code] La lenteur des déplacements des tardigrades est due à l'absence de muscles transverses (ils n'ont que des muscles longitudinaux lisses)[4]. OpenStax College. Get Your Textbooks for Free (or Cheap) Seaquence. NASA | Seeing Photosynthesis from Space. Le dilemme du prisonnier a enfin été testé... sur des prisonniers. Les humains sont-ils moins égoïstes, calculateurs et méfiants que ne le supposent certaines théories économiques lorsqu’ils agissent en société? Les chercheurs Menusch Khadjavi et Andreas Lange du département d’économie de l’université de Hambourg ont testé, sans doute pour la première fois, le célèbre dilemme du prisonnier sur des prisonnières d’un pénitencier de Basse-Saxe ainsi que sur des étudiants, relate Business Insider.

Leurs résultats complets seront publiés en août dans la revue Journal of Economic Behavior & Organization. Et ces résultats sont surprenants. publicité Le dilemme du prisonnier, le plus célèbre de la théorie des jeux, démontre normalement que face à une incertitude concernant le choix d’un autre individu, le premier a intérêt à le trahir. Dans le cas fictif du dilemme du prisonnier, les participants risquent jusqu'à 10 ans de prison. À lire aussi sur Slate.fr. Database download. Wikipedia offers free copies of all available content to interested users. These databases can be used for mirroring, personal use, informal backups, offline use or database queries (such as for Wikipedia:Maintenance). All text content is multi-licensed under the Creative Commons Attribution-ShareAlike 3.0 License (CC-BY-SA) and the GNU Free Documentation License (GFDL).

Images and other files are available under different terms, as detailed on their description pages. For our advice about complying with these licenses, see Wikipedia:Copyrights. Where do I get... English-language Wikipedia[edit] Dumps from any Wikimedia Foundation project: Wikipedia dumps in SQL and XML: – Current revisions only, no talk or user pages. Other languages[edit] In the directory you will find the latest SQL and XML dumps for the projects, not just English. Dealing with compressed files[edit] Bonnie Bassler sur la manière de communiquer des bactéries.

Quorum sensing. Quorum sensing is a system of stimulus and response correlated to population density. Many species of bacteria use quorum sensing to coordinate gene expression according to the density of their local population. In similar fashion, some social insects use quorum sensing to determine where to nest. In addition to its function in biological systems, quorum sensing has several useful applications for computing and robotics. Quorum sensing can function as a decision-making process in any decentralized system, as long as individual components have: (a) a means of assessing the number of other components they interact with and (b) a standard response once a threshold number of components is detected. Bacteria[edit] Some of the best-known examples of quorum sensing come from studies of bacteria. Mechanism[edit] Model of quorum sensing.

Examples[edit] Aliivibrio fischeri[edit] Escherichia coli[edit] Salmonella enterica[edit] Salmonella encodes a LuxR homolog, SdiA, but does not encode an AHL synthase. Fast, Accurate Detection of 100,000 Object Classes on a Single Machine. Ce morceau de verre peut stocker vos données pour toujours ! Voyez-vous ce morceau de verre sur l'image ? Il est comme qui dirait magique, il est capable de stocker vos données pour toujours ! Les données sont comme beaucoup de choses, périssables. Votre musique, vos films, vos documents, vos fichiers, votre ordinateur, tous ont une durée de vie limitée et finiront inexorablement par mourir.

Oui, nous aussi, cela nous rend triste. Et s’il était possible de les faire vivre pour toujours ? Les CD et disques durs ne peuvent survivre que durant quelques décennies ou un siècle tout au plus, ce nouveau verre à base de quartz peut ‘supporter des températures extrêmes et des conditions hostiles sans se dégrader, presque pour toujours.’ Les données sont stockées sous forme binaire grâce à des points intégrés au sein d’une fine feuille de verre de quartz. ‘Le prototype mesure de deux centimètres de large et à peine deux millimètres d’épaisseur. Le prototype peut actuellement accueillir quatre couches de points de 40 méga-octets par pouce. World's Thinnest Transistor is Two-Thirds Complete. The high-tech devices of Silicon Valley depend on tiny, hard silicon chips. Yet in an imagined future in which walls, windows and clothes act as computing devices, the hardware components would have to be soft and flexible.

One research group has taken a first step toward that flexible future, combining a conductor and an insulator in the thinnest sheet possible ? Just one atom thick. "This work shows that it is possible to bring together these two materials. What we believe that opens the doors to is the ability to create these atomically thin electronics, or more-complicated stacked electronics," said Mark Levendorf, a graduate student who worked on the new material. Levendorf studies nanotech chemistry at Cornell University.

"It's in the early phases," he added. Transistors — the building blocks of all modern digital computers — require a conductor, an insulator and a semiconductor. "That's another thing we're pretty excited about," he told InnovationNewsDaily. Les animaux, aussi, sont sur écoute. Welcome to History Mesh. Home : Nature Materials. Acoustic Levitation of Liquids? What Wizardry Be. Quantum Levitation. Syndrome from Pixar's The Incredibles levitates things on zero-point energy. We study methods [1,2] for the manipulation of the force of the quantum vacuum known as the Casimir force. It is possible to turn the Casimir force from attraction to repulsion and to use it for levitating mirrors on, literally, nothing.

This research may be interesting for applications in nanotechnology, because the Casimir force is the ultimate source of friction for micro- and nano-machines. In the following we explain the science behind Quantum Levitation [1]. Gecko feet [3]. A gecko can hang on a glass surface using only one toe. Field lines of the van der Waals force between two atoms or molecules. What is the van der Waals force? The physics behind the van der Waals force: neutral atoms or molecules electrically polarize each other.

However, the dipole of one molecule does only form in the presence of another particle. Imagine that you replace the molecules by larger bodies, say glass or metal plates. U. If this video doesn’t make your jaw drop … you. Arbimon. ARBIMON Acoustics. ARBIMON. Scientists use iPods, car batteries to build a frog surveillance net. Put this on your playlist: scientists at the University of Puerto Rico have developed a system to monitor wildlife in tropical rainforests, using captured audio in real time to remotely record the sounds made by animals. Using hardware that includes iPods, solar panels, and car batteries, the scientists created a network of radio-connected listening posts around the world that allows them to collect data 24 hours a day over long periods of time.

The sound will help them track the effects of environmental changes—such as deforestation and climate change—on endangered species. The system, called Arbimon (Automated Remote Biodiversity Monitoring Network), was created by a team led by Dr. Mitchel Aide and Dr. Carlos Corrada-Bravo of the University of Puerto Rico. The collected audio is then transmitted over a 900MHz radio signal back to a collection base station—which can be up to 24 miles away—and is uploaded over the Internet to the team's server in Puerto Rico. Loi de Zipf. On nomme Loi de Zipf une observation empirique de la fréquence des mots dans un texte.

Elle a pris le nom de son auteur, George Kingsley Zipf (1902-1950). Cette loi a été par la suite généralisée par Benoit Mandelbrot. Genèse Zipf avait entrepris d'analyser une œuvre monumentale de James Joyce, Ulysse, d'en compter les mots distincts, et de les présenter par ordre de nombre (La notion de nombre en linguistique est traitée à l’article « Nombre grammatical ».) décroissants d'occurrences. Le mot le plus courant revenait 8 000 fois ; le dixième mot 800 fois ; le centième, 80 fois ; et le millième, 8 fois. Ces résultats semblent, à la lumière (La lumière est l'ensemble des ondes électromagnétiques visibles par l'œil humain, c'est-à-dire comprises dans des longueurs d'onde de 380nm (violet)...) d'autres études que l'on peut faire en quelques minutes ( Forme première d'un document : Droit : une minute est l'original d'un acte.

Où s est juste légèrement plus grand que 1. La synthèse de Mandelbrot. [1307.1543] Finding Information Through Integrated Ad-Hoc Socializing in the Virtual and Physical World. Smart People Choke Under Pressure. People perceived as the most likely to succeed might also be the most likely to crumble under pressure. A new study finds that individuals with high working-memory capacity, which normally allows them to excel, crack under pressure and do worse on simple exams than when allowed to work with no constraints. Those with less capacity score low, too, but they tend not to be affected by pressure. "The pressure causes verbal worries, like 'Oh no, I can't screw up,'" said Sian Beilock, assistant professor of psychology at Miami University of Ohio. "These thoughts reside in the working memory. " And that takes up space that would otherwise be pondering the task at hand.

"When they begin to worry, then they're in trouble," Beilock told LiveScience. "People with lower working-memory capacities are not using that capacity to begin with, so they're not affected by pressure. " The findings are detailed this week's issue of Psychological Science.

You Can't Do Simple Maths Under Pressure. Lonely lemurs listen to, understand other species’ warning calls. Conjecture de Poincaré. The unintentional beauty of science and research facilities.

Epistemology

Information theory. Psychology. Materials. Learning & Intelligence. Sociology. Informatique. Synthetic analog computation in living cells : Nature. Gestion de Pannes : l'algorithme des Généraux Byzantins. Emergence. Tragedy of the commons. The Library. Rethink Robotics :: Baxter. 150,000 cloud virtual machines will help solve mysteries of the Universe. D-Wave’s quantum optimizer pitted against traditional computers. Graphics8.nytimes.com/packages/pdf/business/quantum-study.pdf. Kings of Camouflage.

:: University of Southampton. What happens to mercury when it is exposed to. W. H. Calvin's "The Unitary Hypothesis" (1993) Averageness. Counting Characters. Reflections on Simultaneous Impact. Dr Maurice de Gosson : Personal Homepage. Bottlenose - Surf the Stream. Walt Disney Animation Studios. Senior thesis. 10 Awesome Online Classes You Can Take For Free. Biggest Scientific Breakthroughs of 2011. Manfred Mohr. Robotics forecast: cool with a chance of lost humanity. Acoustics Monitoring Program - Icequakes (Bloop) Kung Fu Typing – Keyboard Finger Movement Diagrams. The Sound of Hydrogen.

Apophenia. Scientific History And The Lessons For Today's Emerging Ideas. Ils veulent lire dans le cerveau d'Hawking. 07/03 > BE Italie 105 > Voici la formule des vortex. 07/03 > BE Canada 407 > Une étude prédit un effondrement planétaire irréversible imminent. Livre blanc : nouveaux usages de la veille, 5 pratiques émergentes. What's New. How to Determine If A Controversial Statement Is Scientifically True.

Chronostasis. 07/03 > BE Canada 407 > Conception d'un algorithme d'aide à la prédiction des risques de décès par insuffisance cardiaque. Livre blanc : Quels outils de veille pour demain ?

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