Thursday, August 14, 2014

One weak link in the chain of reasoning

In summary, it is whether these equations Mathematics - meant to describe fluid flow - always have a continuous 3D solution that does not end up becoming pathological adopting physically unrealistic features. This is a problem of mathematical physics whose solution would affect several branches of natural science, weather forecasting in the design of aircraft, for example, and perhaps even with the theory of black holes . Of course, as always in mathematics, it could also have unintended consequences in areas seemingly far removed from the theory of partial differential equations.

The mathematician Mukhtarbay Otelbayev spent 30 years working on the problem of the existence and uniqueness of solutions to the Navier-Stokes equations based on initial conditions.  This mathematical problem has many implications in fluid mechanics.

One weak link in the chain of reasoning

Several mathematicians talents were attacked and not just because the one who finds the solution would be given one of the Millennium Prize of Clay Mathematics Institute and the million dollars that goes with it. In 2006, the mathematician Penny Smith of Lehigh University in Bethlehem, Pennsylvania, thought he had found before Mukhtarbay Otelbaev the solution. She had become disillusioned and withdraw from arxiv article that she posted due to an error in his demonstration. The great mathematician Terence Tao there is also attacked with an innovative approach as he explains on his blog , though without conclusive results yet.

Colleagues of Otelbaev course have undertaken to verify its calculations. The task is difficult in itself and is added to the disadvantage that the Kazakh section of the researcher was written in Russian. Recently, Stephen Montgomery-Smith , a mathematician at the University of Missouri at Columbia who also embarked on the race for the Millennium Prize, sent an email to Mukhtarbay Otelbaev pointing him a problem. The Russian-speaking mathematician had to face the facts by answering: " To my shame, on page 56, the inequality (6.34) is incorrect so the 6.3 proposal is unproven (54 p.). I'm sorry ".

His argument therefore collapses. But the researcher does not abandon. He thinks he should be able to get around the obstacle in the next few months. A similar mishap had reached the British mathematician Andrew Wiles , a professor at Princeton University, best known for demonstrating's last theorem Fermat in 1994, Wiles was on the verge of abandonment after a year of work to correct them as a error in his argument when the path was suddenly opened before him.

Navier-Stokes equations: the problem of the Millennium Prize is not resolved

Navier-Stokes equations: the problem of the Millennium Prize is not resolved

The Millennium Prize of the Institute of Mathematics Clay on the Navier-Stokes Will he escape from the hands of mathematician Mukhtarbay Otelbayev? Kazakh detects an error in its mathematical demonstration but does not disarm either.

Although one can write in a condensed form (the last equation down the blackboard), the Navier-Stokes equations are somewhat complex, involving what is called the tensor σij constraints.  These equations are of great importance for engineers, meteorologists and astrophysicists.  © Olivier Thual

In a previous article, Futura-Sciences leaned in detail resounding statement in January 2014 Mukhtarbay Otelbayev, Kazakh mathematician of the Eurasian National University in Astana, Kazakhstan. This brilliant researcher thought he had solved one of the problems of the Millennium Prize of the Institute of Mathematics Clay: demonstration or refutation, a theorem conjectured long for Navier-Stokes.

The Rose of Jericho belongs to sporophytes

The Rose of Jericho ( Selaginella lepidophylla) belongs to this type, and  the botanists "also called" resurrection plant " . During droughts, it is almost completely empty of its water and can lose up to 97% its mass. She abandons its color green and its cells then come into stasis, a kind of hibernation, maintained until the next rainfall. It can survive for several years.

In case of severe drought, it is detached from its roots and leaves are blowing in the wind in areas where rainfall may be higher. When again immersed in water, the leaves open and green again within hours. It's called the Rose of Jericho, in reference to the biblical town of the same name, again ravaged during the story and always rebuilt.

The Rose of Jericho belongs to sporophytes, it does not produce flowers or seeds but reproduces by spores. If the culture of the plant you are interested, know that you can easily find on the Internet .

The rose of Jericho grows easily on rocks or on a dry, acidic soil. © Sean Steininger

Video: the flower of resurrection is revealed in timelapse

Video: the flower of resurrection is revealed in timelapse

Drought and heat are major threats that face plants during the summer. The Rose of Jericho, also called flower of resurrection and living in the desert of Chihuahua, found a surprising way to remedy the problem.

Desert flora is sometimes surprising. A native of Chihuahua, the rose of Jericho is famous for its ability to survive despite an almost complete absence of water. This property makes it an easy plant to grow. Its main feature is that it folds and unfolds according to rainfall, a grandiose show, which you can enjoy in this timelapse.

Plants have many ways to survive the drought . Some store water in their bodies or sheets, other are covered with hair to reduce evaporation or to reduce the activity of their metabolism . Some plants will allow to dry, giving the impression of death.

A head-up display compatible with the OBD socket of the car

Navdy also will feature a microphone and speaker, allowing the use of its smartphone voice assistant like Google Voice and Apple Siri to dictate text messages , initiate a voice call or invoke a service (navigation assisted listening to music, etc.). Navdy is able to share the screen to manage multiple information simultaneously.  The driver can then make a voice of a hand gesture call while continuing to follow its GPS guidance.  © Navdy

A head-up display compatible with the OBD socket of the car

Yet if the voice interfaces allow drivers to keep their eyes on the road and hands on the wheel, they can be a source of potentially dangerous distraction when used for complex commands. This is also the finding of a study conducted by researchers led by Professor Brian Reimer of the Massachusetts Institute of Technology.

Last summer, Futura-Sciences presented the case head up display  created by Garmin, which projects the guiding GPS on the windshield. Navdy goes further by allowing the user to configure the box so that it displays notifications of their choice and disables others such as SMS, calendar reminders, Twitter , Facebook, WhatsApp, etc. The system is able to handle multiple events to present, for example, a route and share the screen when an incoming call arrives.

The device will also be compatible with taking diagnostic of the car (OBDI-II) for the projection of the speed, tachometer, fuel autonomy or pressure tires . For now, the company designs the applications internally, but plans to open its platform to third-party developers once the product is launched. The housing should be marketed worldwide beginning in 2015, but initially, the interface will be in English only. This is available for pre-order and costs 299 dollars (224 euros). Its price will rise to 499 dollars (373 euros) a month.

Project your smartphone on the windshield with Navdy

Project your smartphone on the windshield with Navdy

The start-up Navdy is preparing to market a high-head display system that interfaces with an Android or iOS smartphone to project all the features and applications on a transparent screen on the windshield of a car. The driver can then control all the voice and gestures.

The head-up display Navdy box connects via Bluetooth with an Android smartphone or iPhone.  It displays all the notifications received by the mobile and allows the driver to control functions through simple gestures and voice.  © Navdy

View their smartphone while driving is not only forbidden, but also very dangerous. However, the temptation to take a look fast on the screen when an alert signals the arrival of an email or a new message on her social network favorite ... Navdy , a start ( start-up ) North American, wants to allow drivers to enjoy the features of their devices without eyes off the road. Also she designed a box that connects wirelessly Bluetooth with smartphone Android or iOS .

This is a head-up display system that installs on the cap of the dashboard. A miniprojecteur disseminates information on a screen transparent 5.1 inch. With a camera infrared , the motorist can control the functions with very simple steps: scanning the index to the left to accept an incoming call even move to the right to refuse, even for the music player.

Of healed in 4 weeks instead of 12 depressions

Fun video games from 50 years would not only be a fun activity but also contribute to help his brain! © Daniel Gale,

Of healed in 4 weeks instead of 12 depressions

The results suggest that these brain training exercises were equally effective in reducing symptoms of depression that escitalopram, more quickly. four weeks instead of two, according to the authors , "72% [of patients] had a complete remission of depression " assures Sarah Morimoto Institute of Geriatric Psychiatry in New York, co-author of the study.

A complete clinical study with a larger number of patients would be needed to confirm these findings, the researchers admit, but they hope their study will encourage more research into alternative therapies for depression proved.

The programs were developed to test a theory that brain aging can be fought through intense practice of this type of game, to regain function of learning and memory lost and improve decision-making in view to improving the state of depressed. Previous research has shown that low levels of certain intellectual functions also led to a poor response to antidepressants.

Fight depression elderly subjects with video games?

Fight depression elderly subjects with video games?

Intellectual stimulation using computer games could, in some older people with severe depression, do as well or better than drugs as a study published in the journal suggests Nature Communications .

A regular player uses another part of his cerebral cortex to perform visuomotor tasks.  Other changes in brain activity may result as the removal of some depressions.  © Jontintinjordan, Creative Commons License

Depression affects many elderly and if psychotherapy and medication antidepressants classics are effective for some of them, for many, these treatments have little effect on the disease, the authors note an article in Nature Communications highlighting the need for more active treatment in geriatrics. "Antidepressant drugs are often slow to act and often incomplete and unstable results. The remissions occur only in one third of patients, " they write.

These American and Chinese experts have created computerized cognitive training programs and tested them on eleven individuals aged 60-89 years, resistant to treatment, to improve their learning skills and memory. They compared their results with those obtained in another study of 33 older adults treated with the antidepressant reference, escitalopram (brand names: Seroplex, Cipralex or Lexapro), instead of their therapy assisted by computer.

The Triassic ornithischians remains are rare

Laquintasaura venezuelae was able to feed on insects and possibly small prey that her diet has most likely been primarily herbivorous.

The Triassic ornithischians remains are rare

The animal did nothing spectacular. It should be about 1 m long, with a height of 25 cm. Called Laquintasaura venezuelae , it was probably herbivorous , though its teeth indicate that on occasion it was not to disdain the insects . What made ​​the price of this discovery is first that it is the first dinosaur found in northern South America. The presence of his cousins ​​in Argentina is, she attested long. This is not just any dinosaur because it is a ornithischien , a famous group that spawned the triceratops and stegosaurus therefore have a common ancestor with Laquintasaura venezuelae .

Someone fossilized remains of Laquintasaura venezuelaeont shown that patterns and their positions on the reconstruction of part of its skeleton.

Yet we know little Triassic ornithischians (three species in the Late Triassic), as well as the beginning of the Jurassic . They are mostly members of the second major group, the saurischians , known to us from that time. Leftover Laquintasaura venezuelae are a new door that opens on the first dinosaurs and their separation into two main groups, the ornithischians and saurischians. The fossils found suggest that these small dinosaurs lived in herds. If that were the case, this is an important finding that would set back at least 40 million years in the past the appearance of this social behavior in ornithischians dinosaurs.

The discovery also questions the geographical distribution of ornithischians. Indeed, paleontologists thought they previously lived only in the regions of Pangaea average high latitudes , those closer to the equator seemed inhospitable. Obviously, they were wrong.

This old dinosaur Venezuelan illuminates the history of ornithischians

This old dinosaur Venezuelan illuminates the history of ornithischians

There is no indication that the triceratops and stegosaurus dinosaur down we just discovered in Venezuela. But Laquintasaura venezuelae certainly had a common ancestor with them because it is a ornithischien. It sheds new light on the history of the first representatives of this great group of dinosaurs in particular suggesting that they lived in herds earlier than previously thought.

Marcelo Sánchez, professor of paleontology at the University of Zurich, posing with a model Laquintasaura venezuelae.  The dinosaur is ornithischien to scale.  © Adrian Ritter / UZH

The dinosaurs appeared here about 230 million years ago, during the Triassic . They survive the mass extinction of the Triassic-Jurassic, or extinction TJ. This event, given the diversity of the biosphere halve and was accompanied by the disappearance of about 20% of species marine, ecological niches will be released which will permit the radiative explosion dinosaurs. It seems clear now that it was caused by climate change caused by the rapid emission of gases from major volcanic eruptions that accompanied the fracturing of Pangaea , the supercontinent of the time.

We are still far from knowing everything about the world of dinosaurs as shown in a recent publication in Proceedings of the Royal Society B . Paleontologists will announce, in fact, the discovery of the fossilized remains of a small old dinosaur about 200 million years in the geological formation of La Quinta, in the Venezuelan Andes, formerly close to the equator.

Friday, August 1, 2014

How to deal with an epileptic seizure?

Above all, "being very close to the screen while being placed in a dark environment is a particularly risky situation," says Dr. Bartolomei. Precisely the scenario in which was the young Chinese at the time of crisis.

READ Seizure translated into mathematical equation
How to deal with an epileptic seizure?

Sometimes spectacular, seizures can be scary. Yet it is important to stay calm. Be aware that most crises pass themselves. Nevertheless, it is recommended that the person lie down and put it on the side protecting her head against the risk of injury. It is particularly important to ensure potentially dangerous objects away.

If convulsions, it is useless to try to prevent the movement. Best to slip a pillow under the head to prevent it might hit the ground.

After the crisis, we must remain attentive to the person because it can remain confused and disoriented for several minutes after the apparent end of the crisis.

Once seizures completed, stabilize the person to the side to clear the airways and prevent saliva or vomit from flowing back into the trachea or lungs.

Video games and epilepsy, which risks?

Please note, the images below may offend the most sensitive:

READ Epilepsy: Definition, Symptoms, Treatment
Video games and epilepsy, which risks?

"The epileptic seizures caused by exposure to a screen only occur in a small proportion of epileptics (less than 5%) said photosensitive" recalls Dr. Fabrice Bartolomei,  a neurologist at the University Hospital of Marseille and Vice President of the French League against Epilepsy .

These people are particularly sensitive to light contrast screens. It is this predisposition that can cause seizures in epileptic patients placed in front of a screen, "he explains.

A priori, the " video games are not more dangerous than the act of watching a movie, because it is the differences in the same image contrast and brightness of the screen that are involved, "says neurologist. "But the fact of interacting with the screen such as having to move objects adds concentration and thus brain stimulation may promote the onset of crises," he said.

But several other parameters vary the risks a crisis occurs in photosensitive epileptic placed before a screen.

For example, TV screens are more dangerous than computer screens and those 100Hz more prone to crises than 50 Hz.

VIDEO. A video game addict filmed in full seizure

VIDEO. A video game addict filmed in full seizure
Hugo Jalinière By Hugo Jalinière
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Posted on 01-08-2014 at 15h32
A + A -
A young Chinese epileptic was filmed while he was a crisis in an internet cafe. The opportunity to recall the connection between video games and seizures.
Internet cafe.  © Vincent Thian / AP / SIPA Internet cafe. © Vincent Thian / AP / SIPA

Epilepsy: Definition, Symptoms, Treatment
New avenues in the treatment of epilepsy
Against epilepsy, clothes online
CRISIS. Images are impressive. A gamer addicted to video games was filmed in full seizure while playing online in a cybercafé July 22, 2014 in the city of Zhenjiang in China .

This client, named Zhang, had a seizure after spending several hours playing an online video game in front of his computer screen. Soon, the players around him are alarmed convulsions which it is made and launch the alert.

The police quickly intervened to rush the boy to the hospital. More fear than harm for the young Zhang who, after examination at the hospital, has recovered well from his seizure and doing well. 

IN PICTURES. J-6 before a historic rendezvous in space

IN PICTURES. J-6 before a historic rendezvous in space
Erwan Lecomte By Erwan Lecomte
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Posted on 01-08-2014 19:00
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The excitement is gaining space agencies around the world as and when the distance is reduced between the Rosetta comet probe and  / 67P Churyumov-Gerasimenko it must address.
July 31.  Only 1327 km separate Rosetta Comet 67P / Churyumov-Gerasimenko.  ESA / Rosetta / NavCam July 31. Only 1327 km separate Rosetta Comet 67P / Churyumov-Gerasimenko. ESA / Rosetta / NavCam

SUSPENSE. This is August 6 that the high-risk match must occur between Rosetta and Comet 67P / Churyumov-Gerasimenko. The spacecraft that flies in the area since 2004 since the footsteps of this wandering star then provide new images for humanity.

Such images have already begun to reach us since the revival of the probe Monday, January 20, after 31 months of hibernation.

The gradual approach of Rosetta to comet 67P / Churyumov-Gerasimenko.

To understand everything about the Rosetta mission, its history its objectives, find this episode in our series Live Space dedicated to him.

Space Live 1: Rosetta, an appointment with a ... by sciencesetavenir

This grasshopper the size of a rose thorn

A sample of amber from the Dominican Republic. Kaitlin and Kevin Southworth.

RARITY . But the centerpiece of this inventory, which is not yet complete, is a small grasshopper "size of a rose thorn" write its discoverers in the journal Zookeys . She was baptized Electrotettix attenboroughi in honor of Sir David Attenborough, British naturalist. She probably ate mosses, algae and fungi. "The locusts are very rare in amber and it is extraordinarily well preserved specimen" says Sam Heads, paleontologist at the University of Illinois.

This grasshopper the size of a rose thorn. Of YouTube screenshot.

STEP . Besides its excellent preservation, this specimen is notable because it represents an intermediate stage in the evolution subfamily of crickets and grasshoppers. The oldest representatives of this group had wings, while their modern counterparts do not. The grasshopper has what appears to be rudimentary wings, outdated structures that had already lost their primary function.

"Fossil insects can tell us about the evolution and ecosystem of the ancient world. Probably better than dinosaur bones!" Sam concludes Heads.

A miniature grasshopper preserved in amber

A miniature grasshopper preserved in amber

Joel Ignasse
By Joel Ignasse
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It comes from a collection of Dominican Republic that scientists are just beginning inventory.

The specimen grasshopper found frozen in amber.  ZOOkeys The specimen grasshopper found frozen in amber. ZOOkeys

AMBER . Frozen in amber, many fossils around the world testify to the history of our planet. The amber chips in question here were collected in the 1950s by an entomologist named Milton Sanderson. They come from a deposit in the Dominican Republic and are dated 20 million years.

Milton Sanderson front of amber samples. Milton Sanderson family.

A long and painstaking

Many fossils discovered at the time were written about in the journal Science in 1960, but many treasures were still waiting scientists. They have undertaken since 2010 a new examination of these pieces of amber that are now marked and obscured by oxidation. To see through, they should overlap and polish again. A painstaking but successful: many fossils of flies, bees, arthropods, plants and even a bit of mammal were found.

Clinical trials of anti-malarial vaccines

"This study" provides a number of new vaccine candidates that offer real hope "-  Dr. Faith Osier,  Medical Research Institute of Kenya (KEMRI)

Malaria is responsible for over 600,000 deaths per year worldwide, mostly young children in sub-Saharan Africa.

Complete protection against malaria?

Researchers followed for more than six months a carrying malaria parasites group of children. Some have developed the disease, while others have been protected by natural antibodies have impeded their parasites to penetrate blood cells and their spared severe symptoms (fever, anemia).

Blood samples from these have helped to identify combinations of antibodies can confer complete protection against malaria, said the researchers.

Clinical trials of anti-malarial vaccines in the past focused on a single target and had limited success, "said Dr. Julian Rayner, the Sanger Institute in the UK, one of the authors of the study.

"With this approach, we can systematically test a greater number of targets as well as combinations of targets," he says.

The Anopheles mosquito is a major vector of malaria in the world. Apart from the growing resistance to antimalarial drugs, mosquitoes are less affected by insecticides. This phenomenon makes it all the more important search for new vaccine solutions.

Malaria: towards a "total protection"?

Malaria: towards a "total protection"?

Sciences et Avenir with AFP
By Sciences et Avenir with AFP
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A team of researchers has identified previously unknown antibody may result in developing highly effective vaccine against malaria.

VACCINE. A team of researchers has identified previously unknown antibody may result in developing vaccines against the parasite Plasmodium falciparum , responsible for the most severe form of malaria, according to a study published Wednesday, July 30 in the journal Science Translational Medicine .

By submitting a large number of parasite proteins with antibodies naturally produced by the immune infected children in Kenya system, scientists have identified previously unknown antigens.

They also found new ways to use these antigens, which cause an immune reaction, by combining them with vaccines to enhance protection.

"Resistance to antimalarial treatment (...) is a growing problem that makes it necessary to develop vaccines to combat Plasmodium falciparum before he makes sick people infected, "said Dr. Faith Osier, the Medical Research Institute of Kenya (KEMRI), lead author of the study published in the journal Science Translational Medicine.

the components of the nanoelectronics of the future based on graphene

The various research organizations around the world do not make a mistake,  To determine what kind of shape they had to do, the researchers took advantage of advances in the field of transmission electron microscopy in recent years, based on the correction of spherical aberration . In this way, we can increase the resolution of the images obtained with beams of electrons and observe atomic structures with a resolution of less than a nanometer . In this case, it was possible to see the distribution of carbon atoms on the edges of nanoribbons of graphene whose width is the scale of a few nanometers.

The experiment began with determination of their forms as they were driven by weak electric currents and use of low intensity electron beams. By increasing these two intensities, the structure of nanoribbons began to deteriorate. It was then possible to study jointly, as of this evolution, the correlation between the shape of the nanoribbons and their conduction properties while assessing their resistance to degradation in passing a current of a given intensity . It was superior to that of copper nanoribbons. Physicists have been able to follow the details of these changes until their widths are less than one nanometer, that is to say the space be occupied 5 carbon atoms aligned.

Newly acquired knowledge should help researchers design the components of the nanoelectronics of the future based on graphene.

graphene are conducted by members of the University of Pennsylvania

it is not surprised to learn that work on graphene are conducted by members of the University of Pennsylvania, who, with colleagues Belgian and Korean, just published in Nano Letters article on this subject.

Graphene could have many applications in electronics and even medical researchers as explained in this video. For a French translation can be quite loyal, click the rectangle with two horizontal bars on the bottom right. Subtitles in English should then appear, if it is not already. By simply moving the mouse over the rectangle, you should see the words "Translate subtitles." Click to bring up the menu language selection, select "French" and then click "OK". © University of Pennsylvania, YouTube

Of graphene nanoribbons for future electronics

Physicists want to know how involved a graphene sheet with edges cut to different shapes when traversed by an electric current . For the first time, they managed to combine in a single experiment and observation cutting a ribbon of graphene in a given pattern and the extent of its conductive properties.