Sciences du 01/07/2014

Progeria, une piste pour freiner le vieillissement accéléré 2014-07-01_16:12:34 +0200 01 Jul 2014 04:12 pm | Anonymous Des chercheurs viennent d'identifier une molécule prometteuse contre le syndrome de Hutchinson-Gilford ou Progeria, une maladie génétique rare qui provoque le vieillissement prématuré chez l'enfant et son décès avant l'âge adulte. Suite Impression 3D, contrefaçon et physique quantique - Ze Small Factory 2014-07-01_11:23:25 GMT 01 Jul 2014 01:23 pm | Anonymous Ze Small Factory Impression 3D, contrefaçon et physique quantique Ze Small Factory Ce sont des nanocristaux semiconducteurs, suffisamment petits pour être régis par les lois de la physique quantique. Une de leurs propriétés est qu'ils vont pouvoir rayonner dans une couleur bien spécifique quand ils vont être éclairés par un certain ... Suite Churyumov-Gerasimenko produit 300 ml d'eau par seconde 2014-07-01_13:18:30 +0200 01 Jul 2014 01:18 pm | Anonymous 01/07/2014 La comète Churyumov-Gerasimenko dégaze chaque seconde 300 ml d'eau, soit l'équivalent d'une canette de soda. Cette mesure a été réalisée par l'instrument MIRO de la sonde Rosetta, alors que la comète était encore à près de 600 millions de kilomètres du Soleil (pour comparaison, la comète Hartley 2 dégazait 230 litres par seconde lors de son passage à 160 millions de km du Soleil en 2010). Les scientifiques de la mission suivent attentivement l'évolution du dégazage de Churyumov-Gerasimenko à mesure qu'elle s'approche du Soleil. Ce paramètre sera crucial lorsqu'il faudra s'approcher à quelques dizaines de kilomètres de son noyau et y déposer le robot Philae, en novembre.... Suite Comment s'est forgée l'image d'Ivan le Terrible 2014-07-01_13:00:57 +0200 01 Jul 2014 01:00 pm | Anonymous Auteur d'une biographie consacrée à Ivan le Terrible, l'historien Pierre Gonneau nous éclaire sur la personnalité complexe et contrastée du premier tsar de Russie. Suite Marcher pour combattre l'arthrose… 2014-07-01_08:21:42 +0000 01 Jul 2014 10:21 am | Anonymous L'arthrose est une affection qui se traduit par une destruction progressive du cartilage, le tissu qui entoure la tête des os au niveau des articulations. Cette pathologie fréquente chez les seniors peut devenir très douloureuse et invalidante. en lire plus Suite Observation de l'anxiété pour la première fois chez un invertébré 2014-07-01_08:16:25 +0000 01 Jul 2014 10:16 am | Anonymous Pour la première fois, des chercheurs du CNRS et de l'Université de Bordeaux viennent de produire et d'observer un comportement d'anxiété chez l'écrevisse, qui disparaît lorsqu'on lui injecte une dose d'anxiolytique. L'anxiété peut être définie comme une réponse comportementale au stress consistant en une appréhension durable des événements à venir. Elle prépare les individus à détecter les menaces et à les anticiper de façon adaptée. Elle favorise donc leur survie. Cependant, lorsque le stress est chronique, l'anxiété devient pathologique et peut conduire à un état dépressif. en lire plus Suite L'efficacité des médicaments évaluée avec la chimio-protéomique 2014-07-01_08:06:47 +0000 01 Jul 2014 10:06 am | Anonymous Une étude européenne dirigée par Tatiana Bonaldi (Institut Européen d'Oncologie) a permis de clarifier l'efficacité d'une nouvelle molécule anti-cancer, appelée E-3810, en découvrant des cibles possibles pour le médicament, jusque-là inconnues, et qui ouvrent les portes à de nouvelles applications thérapeutiques importantes. en lire plus Suite CERN and UNESCO celebrate anniversary of CERN Convention 2014-07-01_07:54:44 +0000 01 Jul 2014 09:54 am | Anonymous The sixth session of the CERN Council took place in Paris, from 29 June to 1 July 1953. It was here that the Convention establishing CERN was signed, subject to ratification, by 12 states (Image: CERN) At a ceremony today at UNESCO headquarters in Paris, France, CERN and UNESCO are commemorating the signature of the CERN Convention and the subsequent 60 years of science for peace. On 1 July 1953 in Paris, under the auspices of UNESCO, 12 founding member states signed the Convention that led, in 1954, to the establishment of the European Organization for Nuclear Research. The Convention entered into force on 29 September 1954, the official date of the Laboratory's foundation. CERN was created with a view to relaunching fundamental research in Europe in the aftermath of the Second World War and 60 years on it has become one of the world's most successful examples of scientific collaboration. For 60 years, CERN has brought together scientists from all around the globe and has provided society with numerous benefits through research, innovation and education. Don't miss today's live webcast from UNESCO headquarters, from 10am CET. Available here. Order of ceremony 10 am - 11 am Opening of Ceremony by Maciej Nalecz, Director of the Division of Science Policy and Capacity Building, UNESCO Address by Irina Bokova, Director-General of UNESCO Address by Rolf Heuer, Director-General of CERN Video clip "CERN: 60 years of science for peace" Address by Agnieszka Zalewska, President of the CERN Council Hommage to François de Rose, one of CERN's founding fathers, by his daughter Laurence Rousselot CERN as seen by a young phycisist, Claire Lee (ATLAS Collaboration) 11 am - 12 pm Roundtable discussion on "Science for Peace", moderated by Katya Adler, a renowned journalist. Speakers Lalla Aïcha Ben Barka, Assistant Director-General of Africa Department, UNESCO Alexei Grinbaum, Researcher & Philosopher, Commissariat à l'énergie atomique et aux énergies alternatives (CEA-LARSIM) Fernando Quevedo, Director of the Abdus Salam International Centre for Theoretical Physics (ICTP) Zehra Sayers, Co-chair of SESAME's Scientific Advisory Committee Jan Van Den Biesen, Vice-President of Philips Research Public R&D Programs 12 pm - 12.15 pm Closing remarks by Frédérick Bordry, Director of Accelerators and Technology, CERN. This event has been organised within the framework of #CERN60 events. In 2014, CERN is celebrating 60 years of science for peace. Suite Diaporama : les 10 ans de Cassini dans le monde de Saturne 2014-07-01_09:32:00 +0200 01 Jul 2014 09:32 am | Xavier Demeersman, Futura-Sciences Voilà 10 ans déjà que la sonde spatiale Cassini explore avec succès les mondes de Saturne. Outre les images extraordinaires du « seigneur des anneaux » et les gros plans de ces satellites naturels, les scientifiques doivent à la mission plusieurs découvertes majeures comme les pluies et les lacs... Suite Pascale Delecluse, nouvelle directrice de l'Institut national des sciences de l'Univers du CNRS 2014-07-01_00:00:00 +0100 01 Jul 2014 01:00 am | Anonymous Pascale Delecluse est nommée directrice de l'Institut national des sciences de l'Univers (INSU) du CNRS par Alain Fuchs, président de l'organisme. Chercheur au CNRS durant 26 ans, cette océanographe et climatologue a permis des avancées scientifiques majeures sur le phénomène El Niño et les interactions océan-atmosphère. Pascale Delecluse occupait le poste de directeur adjoint de la recherche à Météo-France depuis septembre 2006. Elle entre en fonction au CNRS mardi 1er juillet 2014 et succède à Michel Diament qui a assuré l'intérim à la tête de l'institut depuis le décès de Jean-François Stéphan en décembre 2013 et qui restera directeur adjoint scientifique en sciences de la Terre à l'INSU. Suite La biodistribution des nanotubes de carbone dans l'organisme 2014-07-01_00:00:00 +0100 01 Jul 2014 01:00 am | Anonymous . Suite Why We Need an Event Viewer 2014-06-30_22:44:55 +0000 01 Jul 2014 12:44 am | Anonymous There’s a software tool I use almost every day, for almost any work situation. It’s good for designing event selections, for brainstorming about systematic errors, and for mesmerizing kids at outreach events. It’s good anytime you want to build intuition about the detector. It’s our event viewer. In this post, I explain a bit about how I use our event viewer, and also share the perspective of code architect Steve Jackson, who put the code together. The IceCube detector is buried in the glacier under the South Pole. The signals can only be read out electronically; there’s no way to reach the detector modules after the ice freezes around them. In designing the detector, we carefully considered what readout we would need to describe what happens in the ice, and now we’re at the stage of interpreting that data. A signal from one detector module might tell us the time, amplitude, and duration of light arriving at that detector, and we put those together into a picture of the detector. From five thousand points of light (or darkness), we have to answer: where did this particle come from? Does the random detector noise act the way we think it acts? Is the disruption from dust in the ice the same in all directions? All these questions are answerable, but the answers take some teasing out. To help build our intuition, we use event viewer software to make animated views of interesting events. It’s one of our most useful tools as physicist-programmers. Like all bits of our software, it’s written within the collaboration, based on lots of open-source software, and unique to our experiment. It’s called “steamshovel,” a joke on the idea that you use it to dig through ice (actually, dig through IceCube data – but that’s the joke). Meet Steve Jackson and Steamshovel Steve Jackson’s job on IceCube was originally maintaining the central software, a very broad job description. His background is in software including visualizations, and he’s worked as The Software Guy in several different physics contexts, including medical, nuclear, and astrophysics. After becoming acquainted with IceCube software needs, he narrowed his focus to building an upgraded version of the event viewer from scratch. The idea of the new viewer, Steamshovel, was to write a general core in the programming language C++, and then higher-level functionality in Python. This splits up the problem of drawing physics in the detector into two smaller problems: how to translate physics into easily describable shapes, like spheres and lines, and how to draw those spheres and lines in the most useful way. Separating these two levels makes the code easier to maintain, easier to update the core, and easier for other people to add new physics ideas, but it doesn’t make it easier to write in the first place. (I’ll add: that’s why we hire a professional!) Steve says the process took about as long as he could have expected, considering Hofstadter’s Law, and he’s happy with the final product. A Layer of Indirection  As Steve told me, “Every problem in computer science can be addressed by adding a layer of indirection: some sort of intermediate layer where you abstract the relevant concepts into a higher level.” The extra level here is the set of lines and spheres that get passed from the Python code to the C++ code. By separating the defining from the drawing, this intermediate level makes it simpler to define new kinds of objects to draw. A solid backbone, written with OpenGL in C++, empowers the average grad student to write software visualization “artists” as python classes. These artists can connect novel physics ideas, written in Python, to the C++ backbone, without the grad student having to get into the details of OpenGL, or, hopefully, any C++. Here’s a test of that simplicity: as part of our week-long, whirlwind introduction to IceCube software, we taught new students how to write a new Steamshovel artist. With just a week of software training, they were able to produce them, a testament to the usability of the Steamshovel backbone. This separation also lets the backbone include important design details that might not occur to the average grad student, but make the final product more elegant. One such detail is that the user can specify zoom levels much more easily, so graphics are not limited to the size of your computer screen. Making high-resolution graphics suitable for publication is possible and easy. Using these new views, we’ve made magazine covers, t-shirts, even temporary tatoos. Many Platforms, Many People IceCube has an interesting situation that we support (and have users) running our software on many different UNIX operating systems: Mac, Ubuntu, Red Hat, Fedora, Scientific Linux, even FreeBSD. But we don’t test our software on Windows, which is the standard for many complex visualization packages: yet another good reason to use the simpler OpenGL. “For cross-platform 3D graphics,” Steve says, “OpenGL is the low-level drawing API.” As visualization software goes, the IceCube case is relatively simple. You can describe all the interesting things with lines and spheres, like dots for detector modules, lines and cylinders for the cables connecting them or for particle tracks, and spheres of configurable color and size for hits within the detector. There’s relatively little motion beyond appearing, disappearing, and changing sizes. The light source never moves. I would add that this is nothing – nothing! – like Pixar. These simplifications mean that the more complex software packages that Steve had the option to use were unnecessarily complex, full of options that he would never use, and the simple, open-source openGL was perfectly sufficient. The process of writing Steamshovel wasn’t just one-man job (even though I only talked to one person for this post). Steve solicited, and received, ideas for features from all over the collaboration. I personally remember that when he started working here, he took the diligent and kind step of sitting and talking to several of us while we used the old event viewer, just to see what the workflow was like, the good parts and the bad. One particularly collaborative sub-project started when one IceCube grad student, Jakob, had the clever idea of displaying Monte Carlo true Cherenkov cones. We know where the simulated light emissions are, and how the light travels through the ice – could we display the light cone arriving at the detector modules and see whether a particular hit occurred at the same time? Putting together the code to make this happen involved several people (mainly Jakob and Steve), and wouldn’t have been possible coding in isolation. Visual Cortex Processing The moment that best captured the purpose of a good event viewer, Steve says, was when he animated an event for the first time. Specifically, he made the observed phototube pulses disappear as the charge died away, letting him see what happens on a phototube after the first signal. Animating the signal pulses made the afterpulsing “blindingly obvious.” We know, on an intellectual level, that phototubes display afterpulsing, and it’s especially strong and likely after a strong signal pulse. But there’s a difference between knowing, intellectually, that a certain fraction of pulses will produce afterpulses and seeing those afterpulses displayed. We process information very differently if we can see it directly than if we have to construct a model in our heads based on interpreting numbers, or even graphs. An animation connects more deeply to our intuition and natural instinctive processes. As Steve put it: “It brings to sharp relief something you only knew about in sort of a complex, long thought out way. The cool thing about visualization is that you can get things onto a screen that your brain will notice pre-cognitively; you don’t even have to consciously think to distinguish between a red square and a blue square. So even if you know that two things are different, from having looked carefully through the math, if you see those things in a picture, the difference jumps out without you even having to think about it. Your visual cortex does the work for you. [...] That was one of the coolest moments for me, when these people who understood the physics in a deep way nonetheless were able to get new insights on it just by seeing the data displayed in a new way. “ And that’s why need event viewers. Suite Top article du mois de septembre 2013 2014-07-01_00:00:00 +0200 01 Jul 2014 12:00 am | omni@neamar.fr (Top) Voici venu le temps de donner les résultats ! Après une semaine de vote, l'article du mois de septembre 2013 a été sélectionné. Sans plus attendre, le vainqueur est… La punition est-elle plus efficace que la récompense ? par Moroh. La carotte ou le bâton ? Et les articles qui suivent dans le top 5 sont : La Hulotte, le journal le plus lu dans les terriers. Connaissez-vous le journal la Hulotte ? La triste vie de Charles Goodyear. Qui fut le véritable inventeur de la vulcanisation ? Les roux n'ont pas d'âme ! . Pourquoi dit-on que les roux n'ont pas d'âme ? L'esquimau et son bâton. D'où vient la glace esquimau ? Les votes sont maintenant ouverts pour élire l'article du mois de octobre 2013. Les résultats seront annoncés dimanche prochain. Suite Study helps unlock mystery of high-temp superconductors 2014-06-30_16:39:23 EDT 30 Jun 2014 10:39 pm | Anonymous Physicists say they have unlocked one key mystery surrounding high-temperature superconductivity. Their research found a remarkable phenomenon in copper-oxide (cuprate) high-temperature superconductors. Suite Reigning in chaos in particle colliders yields big results 2014-06-30_14:08:32 EDT 30 Jun 2014 08:08 pm | Anonymous Physicists have published details on an important method of detecting and correcting unwanted chaotic behavior in particle colliders. The method is helping accelerator physicists design high-performing, cost-efficient accelerators in an era of constrained science budgets. Suite Interlayer distance in graphite oxide gradually changes when water is added 2014-06-30_11:41:39 EDT 30 Jun 2014 05:41 pm | Anonymous Physicists have solved a mystery that has puzzled scientists for half a century. They show with the help of powerful microscopes that the distance between graphite oxide layers gradually increases when water molecules are added. That is because the surface of graphite oxide is not flat, but varies in thickness with 'hills' and 'valleys' of nanosize. Suite Espoir pour la spintronique, les skyrmions se révèlent sous les rayons X 2014-06-30_17:38:00 +0200 30 Jun 2014 05:38 pm | webmaster@futura-sciences.com (Futura-Sciences) Dans un milieu magnétique, les skyrmions sont des sortes de tourbillons formés par l'orientation de l'aimantation de paquets d'atomes de petites tailles. Leur exploitation pourrait conduire à une miniaturisation des mémoires magnétiques et à des progrès en spintronique. Pour la première fois,... Suite Contre le contrôle total. Mettre en place des comités citoyens de vigilance 2014-06-30T14:29:43Z Quantum dots created with single-atom precision 2014-06-30_09:45:35 EDT L'eau dans le système solaire 2014-06-30_12:00:00 +0100

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