La capacité d'une population à innover dépend aussi de sa taille Dans une étude publiée par la revue Nature, une équipe de l'Institut des sciences de l'évolution de Montpellier, CNRS/IRD/Université de Montpellier 2, a prouvé par l'expérience l'hypothèse selon laquelle la taille d'une population influait directement sur sa capacité à transmettre des traits culturels. Plus une population est grande, plus elle est capable de transmettre des savoirs et des techniques mais aussi d'innover ; plus elle est petite, plus elle risque de perdre son savoir-faire et de régresser. Le développement d'outils ou de techniques d'une remarquable complexité a permis à notre espèce (Dans les sciences du vivant, l’espèce (du latin species, « type » ou « apparence ») est le taxon de base de la systématique....) de coloniser une gamme d'environnements plus large qu'aucune autre espèce de vertébrés (Les vertébrés forment un sous-embranchement du règne animal. Ce taxon, qui dans sa version moderne exclut les myxines, est considéré comme monophylétique. Référence:
Pierre Apkarian N. V. Q. Hung, H. N. A. V. A. A. P. P. Microscopic particles self-organize into a rolling mob One of the nearly infinite number of astounding sights in the animal kingdom plays out when creatures get together in large groups. Whether it’s a flock of birds or a school of fish, the group can take on an identity of its own, moving in seemingly perfect coordination. People have long puzzled over how this wonderful choreography works. The flocking pattern is not directed by some controlling leader; it emerges from the behavior of individuals. Antoine Bricard, Jean-Baptiste Caussin, and three of their colleagues have come up with a unique setup to build on previous studies. That is, until you increase the number of spheres beyond a threshold of crowding. The researchers started by creating little “racetracks” for the spheres to roll around on. Given a square enclosure in which to roam instead of circular racetracks, the spheres settled into a very different pattern. There are two interactions that the researchers think are enabling the particles to put on these displays.
Fini les embouteillages grâce à un algorithme du MIT Alors que le long week-end de la Toussaint approche, Bison futé a classé orange la journée de samedi pour le sens des départs et prévoit une circulation fluide pour dimanche. Cette fois-ci, les automobilistes ont de la chance, ils n’auront pas à attendre des heures dans leur voiture qu’un embouteillage, sans cause apparente, se désagrège de lui-même. Mais bientôt, ces bouchons fantômes ne seront sans doute qu’un mauvais souvenir, grâce à un algorithme développé par Berthold Horn, chercheur au MIT. Le problème dans ces embouteillages, qui ne sont la conséquence ni de travaux ni d’accidents, selon le scientifique, ce sont les changements de rythme des véhicules. publicité Il explique dans un article du MIT: «Imaginez que vous introduisiez une perturbation en freinant brusquement, juste un instant, elle se propagera en amont et son amplitude augmentera à mesure qu’elle s’éloigne de vous.» L’idée de Horn est donc de réguler le flot de voitures en évitant les ralentissements intempestifs.
Synthèse – Vers des agricultures à hautes performances Publié le 14 / 10 / 13 Demain, l’agriculture devra concilier des performances productives, économiques, environnementales et sociales. Le Commissariat général à la stratégie et à la prospective a sollicité l’Institut national de la recherche agronomique pour mener une réflexion sur les possibilités d’évolution de l’agriculture française vers des systèmes de production multiperformants et sur les conditions de leur déploiement en France. Vers des agricultures à hautes performances D’ici dix ans, la ferme France aura profondément évolué. Grâce à de nombreuses initiatives, la transition est déjà en route. Comment rendre l’agriculture biologique plus productive et plus compétitive ? La transition à grande échelle des exploitations françaises vers la multiperformance exige des changements majeurs. L’agriculture biologique en débat L’étude « Comment rendre l’agriculture biologique française plus productive et plus compétitive ?
Network theory A small example network with eight vertices and ten edges. It has applications in many disciplines including statistical physics, particle physics, computer science, electrical engineering, biology, economics, operations research, and sociology. Applications of network theory include logistical networks, the World Wide Web, Internet, gene regulatory networks, metabolic networks, social networks, epistemological networks, etc; see List of network theory topics for more examples. Euler's solution of the Seven Bridges of Königsberg problem is considered to be the first true proof in the theory of networks.[1] Network optimization[edit] Network analysis[edit] Social network analysis[edit] Visualization of social network analysis.[2] Biological network analysis[edit] With the recent explosion of publicly available high throughput biological data, the analysis of molecular networks has gained significant interest. Narrative network analysis[edit] Narrative network of US Elections 2012[6] Spread[edit]
Birds, bees, and banks: lessons from collapsing ecosystems Figuring out why financial crises emerge in seemingly stable economies is tough. Widespread collapses are notoriously difficult to predict - to do so requires a comprehensive view of a complex, interconnected system. But help may be at hand: experts in finance are now looking to certain fields of ecology to help provide this viewpoint. Ecologists have long been concerned with how connections between species relate to the overall stability of an ecosystem. For example, in the 1940’s a drought-resistant plant native to Africa and Asia known as Buffelgrass was introduced to the south-west America’s Sonoran Desert as a means of feeding cattle. This snowballing cycle can be seen in financial crises as well. So how can one prevent such catastrophic cycles? As it turns out, banks might look to bees and flowers. In a nested network, a specialist with few connections will be connected to a generalist that has many connections, including the all the ones the specialist has.
New Bacterial Life-Form Discovered in NASA and ESA Spacecraft Clean Rooms High atop a platform inside a clean room at the European Space Agency’s (ESA) launch site in South America, scientists painstakingly searched for microbes near the Ariane 5 rocket due to launch the Herschel space telescope in May 2009. Only very unusual organisms can survive the repeated sterilization procedures in clean rooms, not to mention the severe lack of nutrients available. But the scientists’ careful inspection was fruitful, turning up a type of bacteria that had been seen only once before. After the two discoveries, the teams joined forces to analyze the bacterium, and found it was so different from known organisms that it constituted not just a new species, but a new genus, which they described in a paper published in July in the International Journal of Systematic and Evolutionary Microbiology. The researchers named the bacterium Tersicoccus phoenicis. There is no proof that T. phoenicis actually accompanied Phoenix to Mars, but it is possible.
Geoengineering, through the eyes of the IPCC It has been well established that our emissions of greenhouse gases are changing the Earth’s climate and that in order to avoid future warming and ocean acidification, fossil fuel use will need to be limited. There is a sort of “Plan B,” however—the intentional manipulation of the climate, known as “geoengineering.” Some forms of geoengineering could be done relatively easily, while others seem more like “terraforming” schemes out of sci-fi novels. As part of its latest report, the Intergovernmental Panel on Climate Change (IPCC) includes a review of research into the two main categories of geoengineering: the artificial removal of CO2 from the atmosphere and the artificial reduction of sunlight reaching the Earth. Taking off some blankets The removal of carbon dioxide from the atmosphere could take many forms, some of which have much more potential than others. Another popular idea is to enlist the help of phytoplankton. Designer sunglasses There are other known side effects.
The Economics of a Hit TV Show Photo Credit: Lewis Jacobs / AMC Ten million Americans can recall where they were the night of September 29th, 2013. They were watching the series finale of Breaking Bad. And they were watching it on AMC, a cable channel that once cut its teeth airing reruns of black-and-white movies. The suits at the network were prepared. But keeping Breaking Bad on the air was a big investment. And finding a hit like Breaking Bad – or even finding a viable show to put on the air in the first place – often costs networks hundreds of millions of dollars each year in development costs and pricey, failed pilot projects. Things could get even more expensive. This is just the tip of the iceberg. Microsoft recently opened an original content business under CBS veteran Nancy Tellem. Few industries would routinely pay millions per unit of an item, sight unseen, with minimal (and sometimes no) market research. The Creative Marketplace Credit: Sony Pictures Television / NBC George: The show is about...nothing.
Soon, Rich People Will Be Ballooning Through the Stratosphere A new “space tourism” company by the name of World View has announced plans to whisk away wealthy patrons by offering exclusive balloon tours of the stratosphere that can begin as early as sometime in 2015. A specially designed capsule will allow enough room for six passengers and two crew members as well as a complimentary bar. After initial take-off it will only take about an hour and a half for the giant balloon to ascend 18 miles into the stratosphere, at which point it will casually drift along for a couple of hours before eventually descending back to the Earth’s surface.
21 Science Fictions That Became Science Facts In 2013