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Le déploiement des véhicules électriques relancé par une nouvelle mesure (Transport) 4 06 2014 17:12 +0100
04 Jun 2014 06:12 pm | fm.be@adit.fr (BE Chine)
Fin février 2014 et à la suite de plusieurs épisodes de pollution intense en Chine, les autorités locales ont publié une liste de marques de véhicules verts qui peuvent désormais être vendues dans certaines villes chinoises telles que Pékin et Shangh ... |
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Les mathématiques chinoises à la pointe de la géométrie (Mathématiques) 4 06 2014 17:03 +0100
04 Jun 2014 06:03 pm | fm.be@adit.fr (BE Chine)
Comment réconcilier la mécanique quantique qui cherche à comprendre les phénomènes à l'échelle atomique, et la relativité générale qui décrit la gravitation à l'échelle macroscopique ? C'est l'objectif de la théorie des cordes selon laquelle une uniq ... |
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Etat des lieux de la pollution des sols : de nouvelles avancées scientifiques pour stopper la propagation (Environnement) 4 06 2014 16:43 +0100
04 Jun 2014 05:43 pm | fm.be@adit.fr (BE Chine)
Avec plus d'un milliard et trois cent cinquante millions d'habitants (soit environ 20% de la population mondiale) pour seulement 10% de la surface agricole du globe et une ressource en eau très mal répartie, la Chine fait face à un défi majeur : répo ... |
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La géothermie en Chine (Energie) 4 06 2014 16:08 +0100
04 Jun 2014 05:08 pm | fm.be@adit.fr (BE Chine)
La création d'une association nationale pour la géothermie, discutée le 13 mai dernier lors d'un forum tenu à Xinyu (Jiangxi), et dont un des acteurs majeurs serait le Ministère du territoire et des ressources (responsable, entre autres, des ressourc ... |
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Dernières avancées du programme spatial chinois (Espace) 4 06 2014 15:40 +0100
04 Jun 2014 04:40 pm | fm.be@adit.fr (BE Chine)
Le programme spatial chinois est ambitieux et avance à grand pas, aussi bien au niveau des lanceurs que du vol habité ou encore du programme lunaire. Les projets à venir ont été confirmés et précisés au cours de la douzième conférence consultative po ... |
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Détecter l'ADN tumoral par une simple prise de sang ! 2014-06-04_13:21:15 +0000
04 Jun 2014 03:21 pm | Anonymous
Des chercheurs américains de l'Université de Stanford ont mis au point une nouvelle méthode de détection et de quantification de l'ADN tumoral circulant à partir d'un échantillon sanguin. Cet outil permet également d'évaluer avec une grande pertinence l'évolution tumorale après traitement. Cette technique pourrait en outre être étendue à d'autres types de tumeurs solides.
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Vers des batteries à très longue durée de vie… 2014-06-04_13:15:14 +0000
04 Jun 2014 03:15 pm | Anonymous
Des chercheurs américains de l'Oak Ridge National Laboratory (ORNL) ont mis au point une nouvelle batterie plus sûre, dont la durée de vie pourrait atteindre 10 ans sans recharge. Cette batterie fait réagir un carbone fluoré avec du lithium (Li/CFx).
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Les Etats-Unis présentent un plan de réduction des émissions de CO2 sans précédent 2014-06-04_13:08:06 +0000
04 Jun 2014 03:08 pm | Anonymous
Alors que le projet de loi contre le réchauffement climatique est en examen depuis 4 ans par le Congrès américain, Le Président Obama a présenté le 1er juin un plan de réduction de 30 % des émissions de dioxyde de carbone provenant des centrales électriques américaines d'ici quinze ans, par rapport à 2005.
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Des cristaux et des maths 2014-06-04_14:31:05 +0200
04 Jun 2014 02:31 pm | Anonymous
Des yeux de mouche aux ruches d'abeilles, les structures géométriques des cristaux se retrouvent partout dans la nature. Comment l'expliquer ? La question taraude de nombreux mathématiciens, dont Mathieu Lewin, qui nous éclaire sur ce sujet intrigant. |
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En vidéo : le premier vol de Solar Impulse 2 2014-06-04_13:38:00 +0200
04 Jun 2014 01:38 pm | Jean-Luc Goudet, Futura-Sciences
La seconde version de l'avion solaire de Solar Impulse, c'est-à-dire l'appareil qui tentera le tour du monde l'an prochain, a réalisé son premier vol, aux mains d'un pilote d'essai. Les résultats sont annoncés probants : la folle aventure continue. |
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Le chasseur d'exoplanètes SPHERE livre ses premières images 2014-06-04_12:00:00 +0100
04 Jun 2014 01:00 pm | Anonymous
Installé avec succès sur le Très Grand Télescope (VLT) de l'ESO, l'instrument européen SPHERE vient d'obtenir sa première lumière. Ce véritable chasseur d'exoplanètes permettra de détecter en imagerie directe des exoplanètes gazeuses et des disques de poussières autour d'étoiles proches du Soleil (jusqu'à 300 années lumière) avec une finesse et un contraste inégalés. SPHERE (Spectro-Polarimètre à Haut contraste dédié à la REcherche d'Exoplanètes) a été développé par un consortium européen [1] piloté par l'Institut de planétologie et astrophysique de Grenoble (IPAG, CNRS/Université Joseph Fourier) avec l'ONERA, le Laboratoire d'astrophysique de Marseille (CNRS/AMU), le Laboratoire d'études spatiales et d'instrumentation en astrophysique (Observatoire de Paris/CNRS/UPMC/Université Paris Diderot), le laboratoire Lagrange (Observatoire de la Côte d'Azur/CNRS/Université Nice-Sophia Antipolis) ainsi que des instituts allemands, italiens, suisses et néerlandais, en collaboration avec l'ESO (l'Observatoire européen austral). L'instrument sera mis à disposition de la communauté des astronomes en 2015. |
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3D animations bring CERN's first accelerator to life 2014-06-04_08:48:44 +0000
04 Jun 2014 10:48 am | Anonymous
The accelerating cavity of CERN's first accelerator, the Synchrocyclotron (Image: Jacques Herve Fichet/CERN)
There is a blue glow coming from Hall 300 on CERN's Meyrin site. Inside, a 3D projection system is giving the laboratory's first accelerator, the Synchrocyclotron (SC), a new lease of life.
When it was built in 1957, the SC was the highest energy particle accelerator in Europe, and in its 33 years of service it characterized many important physics results, such as the disintegration of the pion. The SC was shut down in 1990 and has lain dormant since.
Now the CERN Education and Radiation Protection groups are jointly overseeing an extensive refurbishment project to turn the SC into a new exhibition point for visitors.
"You enter the hall through the time tunnel," explains Bernard Pellequer who, together with Rolf Landua and Marco Silari is heading the project. "On the walls, timelines go back to the foundation of CERN and beyond, showing important moments in CERN history."
Today participants in the 10 th edition of the Geneva Mapping Festival have gathered to preview the new exhibition. "The idea to organize an event at CERN within the Festival came up when I met the Festival organisers at the CinéGlobe short film festival in March" says Silari.
Participants of the Geneva Mapping Festival attend a preview of the exhibition (Image: Jacques Herve Fichet/CERN)
In the hall the real show begins. An intricate system projects beautifully crafted animations onto the accelerator's surfaces. Whizzing protons flit across the room; magnetic fields expand in clouds of blue haze as a narrator explains a typical Synchrocyclotron run, beginning with prepping the vacuum chamber and getting the electromagnetic field just right, and ending with high-energy protons smashing into a target. Each part of the process is punctuated with 3D display giving a clear picture of how the accelerator worked. It's beautiful.
CERN awarded a contract to Telesonic, a firm based in Basque Country, which together with Eikonos, based in Barcelona, prepared the mapping on the SC. "The technical challenges were considerable," says Mikel Eguren of Telesonic, charged with developing and installing the projection system. Eight projectors simultaneously display six different images onto the accelerator to get the 3D effect. "The projection distance is short, as are the distances between the accelerator's different surfaces. So focusing correctly on the different parts was difficult," says Eguren.
The projection ends and the lights come up, revealing tools and artefacts around the room. On one wall, huge spanners used to tighten the bolts of the accelerator's iconic red magnet. On a nearby desk, an oscilloscope and a mechanical calculator, both used to gather data on particle tracks within the accelerator.
The Synchrocyclotron bathes in the blue neon glow of Hall 300. The large spanners on the wall to the right were used in the 1950s to tighten the bolts on the accelerator's red magnet (Image: Jacques Herve Fichet/CERN)
"We've chosen to display objects that were used at the time," says Pellequer, "to show the technical and scientific context at CERN in the 1950s and 60s – a time before computers and digital cameras."
Director-General Rolf Heuer will inaugurate the new visit point at a ceremony for the CERN Council on 19 June. Representatives of the European Physical Society will take part, as the Synchrocyclotron will be named an EPS Historic Site. It will be open to the general public soon afterwards.
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Le Destrier de l'Immobilier, c'est l'Internet 2014-06-04T06:23:54Z
04 Jun 2014 08:23 am | Anonymous
« Alors que 4.000 agences ont déjà disparu depuis 2008, d'après nos calculs, l'écrémage devrait persister » affirme le XERFI dans un rapport récent, pourtant plutôt fait pour rassurer. Le développement des réseaux de mandataires continue de bouleverser le modèle d'intermédiation traditionnel. Mais c'est un facteur parmi tant d'autres ! Faudra-t-il des lois pour empêcher la disparition de l'intermédiation ? Serait-ce Duproprio le seul restant, pour ne pas (...) - Technologies / Internet, Immobilier |
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IceCube DeepCore and Atmospheric Neutrino Mixing 2014-06-03_21:11:02 +0000
03 Jun 2014 11:11 pm | Anonymous
Today at the Neutrino2014 conference in Boston, the IceCube collaboration showed an analysis looking for standard atmospheric neutrino oscillations in the 20-30 GeV region. Although IceCube has seen oscillations before, and reported them in a poster at the last Neutrino conference, in 2012, this plenary talk showed the first analysis where the IceCube error bands are becoming competitive with other oscillation experiments.
Neutrino oscillation is a phenomenon where neutrinos change from one flavor to another as they travel; it’s a purely quantum phenomenon. It has been observed in several contexts, including particle accelerators, nuclear reactors, cosmic rays hitting the atmosphere, and neutrinos traveling from our Sun. This is the first widely accepted phenomenon in particle physics that requires an extension to the Standard Model, the capstone of which was the observation of the Higgs boson at CERN. Neutrinos and neutrino oscillations represent the next stage of particle physics, beyond the Higgs.
Of the parameters used to describe neutrino oscillations, most have been previously measured. The mixing angles that describe oscillations are the most recent focus of measurement. Just two years ago, the last of the neutrino mixing angles was measured by the Daya Bay experiment. Of the remaining mixing angles, the atmospheric angle accessible to IceCube remains the least constrained by experimental measurements.
IceCube, because of its size, is in a unique position to measure the atmospheric mixing angle. Considering neutrinos that traverse the diameter of the Earth, the oscillation effect is the strongest in the energy region from 20 to 30 GeV, and an experiment that can contain a 20 GeV neutrino interaction must be very large. The Super Kamiokande experiment in Japan, for example, also measures atmospheric oscillations, but because of its small size relative to IceCube, Super Kamiokande can’t resolve energies above a few GeV. At any higher energies, the detector is simply saturated. Other experiments can measure the same mixing angle using accelerator beamlines, like the MINOS experiment that sends neutrinos from Fermilab to Minnesota. Corroborating these observations from several experimental methods and separate experiments proves the strength of the oscillation framework.
The sheer size of IceCube means that neutrinos have many chances to interact and be observed within the detector, giving IceCube a statistical advantage over other oscillation experiments. Even after selecting only the best reconstructed events, the experimental sample remaining still has over five thousand events from three years of data. Previous atmospheric oscillation experiments base analysis on hundreds or fewer events, counting instead on precise understanding of systematic effects.
The IceCube collaboration is composed of more than 250 scientists from about 40 institutions around the world, mostly from the United States and Europe. The current results are possible because of decades of planning and construction, dedicated detector operations, and precise calibrations from all over the IceCube collaboration.
IceCube has several major talks at the Neutrino conference this year, the first time that the collaboration has had such a prominent presence. In addition to the new oscillations result, Gary Hill spoke in the opening session about the high energy astrophysical neutrinos observed over the last few years. Darren Grant spoke about the proposed PINGU infill array, which was officially encouraged in the recent P5 report. IceCube contributed nine posters on far-ranging topics from calibration and reconstruction methods to a neutrino-GRB correlation search. The conference-inspired display at the MIT museum is about half IceCube material, including an 8-foot tall LED model of the detector. One of three public museum talks on Saturday will be from (yours truly) Laura Gladstone about the basics of IceCube science and life at the South Pole.
One new aspect of the new oscillation analysis is that it uses an energy reconstruction designed for the low end of the energy range available to IceCube, in the tens-of-GeV range. In this range, only a handful of hits are visible for each event, and reconstructing directional information can be tricky. “We took a simple but very clever idea from the ANTARES Collaboration, and rehashed it to tackle one of our biggest uncertainties: the optical properties of the ice. It turned out to work surprisingly well,” says IceCuber Juan Pablo Yanez Garza, who brought the new reconstruction to IceCube, and presented the result in Boston. By considering only the detector hits that arrive without scattering, the reconstruction algorithm is more robust against systematic errors in the understanding of the glacial ice in which IceCube is built. |
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Brain signals link physical fitness to better language skills in kids 2014-06-03_11:43:21 EDT
03 Jun 2014 05:43 pm | Anonymous
Children who are physically fit have faster and more robust neuro-electrical brain responses during reading than their less-fit peers, researchers report. These differences correspond with better language skills in the children who are more fit, and occur whether they're reading straightforward sentences or sentences that contain errors of grammar or syntax. |
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Kepler-10c, la première mégaterre 2014-06-03_17:36:00 +0200
03 Jun 2014 05:36 pm | Rémy Decourt, Futura-Sciences
Le bestiaire des exoplanètes compte un nouveau membre. On connaissait les superterres, ces planètes jusqu'à dix fois plus massives que la Terre. Aujourd'hui, on découvre l'existence d'une planète rocheuse 17 fois plus lourde que la nôtre ! Nous ne sommes donc plus à une surprise près. |
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CERN's ALPHA experiment measures charge of antihydrogen 2014-06-03_15:10:38 +0000
03 Jun 2014 05:10 pm | Anonymous
Detail of the ALPHA experiment: Insertion of the ALPHA Penning trap into the cryostat that holds the antihydrogen trapping magnets (Image: Niels Madsen)
In a paper published in the journal Nature Communications today, the ALPHA experiment at CERN's Antiproton Decelerator (AD) reports a measurement of the electric charge of antihydrogen atoms, finding it to be compatible with zero to eight decimal places. Although this result comes as no surprise, since hydrogen atoms are electrically neutral, it is the first time that the charge of an antiatom has been measured to high precision.
"This is the first time we have been able to study antihydrogen with some precision," said ALPHA spokesperson Jeffrey Hangst. "We are optimistic that ALPHA's trapping technique will yield many such insights in the future. We look forward to the restart of the AD program in August, so that we can continue to study antihydrogen with ever increasing accuracy."
Antiparticles should be identical to matter particles except for the sign of their electric charge. So while the hydrogen atom is made up of a proton with charge +1 and an electron with charge -1, the antihydrogen atom consists of a charge -1 antiproton and a charge +1 positron. We know, however, that matter and antimatter are not exact opposites – nature seems to have a one-part in 10 billion preference for matter over antimatter, so it is important to measure the properties of antimatter to great precision: the principal goal of CERN's AD experiments. ALPHA achieves this by using a complex system of particle traps that allow antihydrogen atoms to be produced and stored for long enough periods to study in detail. Understanding matter antimatter asymmetry is one of the greatest challenges in physics today. Any detectable difference between matter and antimatter could help solve the mystery and open a window to new physics.
To measure the charge of antihydrogen, the ALPHA experiment studied the trajectories of antihydrogen atoms released from the trap in the presence of an electric field. If the antihydrogen atoms had an electric charge, the field would deflect them, whereas neutral atoms would be undeflected. The result, based on 386 recorded events, gives a value of the antihydrogen electric charge as (-1.3±1.1±0.4) × 10 -8, the plus or minus numbers representing statistical and systematic uncertainties on the measurement.
With the restart of CERN's accelerator chain getting underway, the laboratory's antimatter research programme is set to resume. Experiments including ALPHA-2, an upgraded version of the ALPHA experiment, will be taking data along with the ATRAP and ASACUSA experiments and newcomer AEGIS, which will be studying the influence of gravity on antihydrogen.
Read more: " An experimental limit on the charge of antihydrogen" – Nature Communications
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Giant magnet parades through downtown Geneva 2014-06-03_14:05:52 +0000
03 Jun 2014 04:05 pm | Anonymous
A superconducting dipole magnet from the Large Hadron Collider passes a theatre in Geneva as part of the "Geneva 200" celebrations (Image: Maximilien Brice/CERN)
Last Saturday, 31 May, CERN joined in the Genève200 celebrations, parading a superconducting magnet through the city's narrow streets on a 20-metre lorry, from the Parc des Bastions to the Port Noir. It was also an opportunity to remind everyone that this year marks 60 years of science for peace at CERN.
The magnet spent almost three hours among the huge crowds, as 30,000 people descended on the harbour in the sunshine to celebrate the bicentenary of Confederate troops landing at the Port Noir, heralding Geneva's integration into Switzerland.
The magnet makes its way along the shore of Lake Geneva (Lac Léman) with Geneva's landmark 140-metre fountain visible through the trees (Image: Maximilien Brice/CERN)
This grand parade, a combination of the historical and the contemporary in the form of a historical retrospective, featured 1200 participants and took the people of Geneva back in time to 1814. The immersion into the past was complete with police officers and period firefighters in period uniforms and even period vehicles, much to the delight of the general public. With a nod to CERN and the LHC, the 21 st Century was not forgotten.
The parade then passed in front of the official guests, who included representatives of each canton and of Geneva's cantonal and communal authorities, as well as the President of the Confederation, Didier Burkhalter.
The event was a true reflection of Geneva – a real cultural, artistic, social and scientific patchwork.
For information about upcoming CERN60 events, see www.cern.ch/cern60
Crowds gather to watch the magnet pass (Image: Maximilien Brice/CERN)
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Les déconnectés volontaires 2014-06-03_14:56:41 +0200
03 Jun 2014 02:56 pm | Anonymous
Mails, SMS, tweets… Face au flux continu issu des technologies de la communication, certains pratiquent la déconnexion volontaire. Ce nouveau comportement a fait l'objet d'une étude pilotée par le sociologue Francis Jauréguiberry. |
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How universal is (lepton) universality? 2014-06-03_12:00:00 +0000
03 Jun 2014 02:00 pm | Anonymous
The LHCb detector in its underground cavern at CERN (Image: CERN)
Just as a picture can be worth a thousand words, so the rarest processes at the Large Hadron Collider (LHC) can sometimes have the most to tell us. By isolating and counting decays of B+ mesons to a kaon and two leptons, the LHCb experiment has tested a key assumption of the Standard Model – lepton universality, the idea that electrons, muons and tau leptons should behave in the same way, and be produced equally often in weak decays. In a presentation given at this week's Large Hadron Collider Physics conference, LHCb results reveal the first hints of a difference.
According to the Standard Model, a B+ meson should decay to a kaon, electron and positron as often as it decays to a kaon, muon and antimuon. If a measurement of both rates shows a difference between them, it could be the first sign of something new. Rare B meson decays provide a particularly good laboratory for testing universality, as the decays proceed in a way that allows new, otherwise unseen, particles to influence the rate seen experimentally. Additional Higgs bosons, or a new, heavy version of the Z boson, could alter the relative rate of electron and muon production and be detected in this way.
If the ratio of the number of decays containing muons, to those containing electrons, is measured instead of the individual rates, many theoretical uncertainties cancel to allow a precise probe of universality. The Belle and Babar experiments have previously measured this ratio, with limited precision, and found it consistent with the Standard Model. With its precise silicon tracker and particle identification systems, and access to large datasets, LHCb is well placed to explore the B+ meson system further.
LHCb has now analysed their entire dataset of proton-proton collisions from the LHC and finds that B+ mesons decay to muons about 25% less often than they decay to electrons. As these decays only occur a couple of times in every 10 million B+ decays the measurement is still dominated by statistical error, even if it is the world's most precise determination. The observed difference has a significance of 2.6 standard deviations, corresponding to a chance of one in a hundred that it is due to a statistical fluctuation. More data from the forthcoming high energy LHC run is needed to confirm if this tantalising result is indeed the first sign of something new in the universe.
Read more: " An interesting result presented at the LHCP conference" – LHCb
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