Senin, 24 November 2014

Rosetta and Philae in search of organic molecules

Those made ​​on the young Earth by asteroids (since we discovered amino acids in meteorites fell to Pride and Murchison ) and comets (also by their dust) have they played a role in the onset of life? If so, which? We can not answer these questions. And that is why Rosetta seeking ...

The waltz around Rosetta comet 67P / Churyumov-Gerasimenko.  The probe continues its work of observation at 20 km from the center of the target.  December 3, it will change orbit and moved 30 km from December 6.  On that day, but it's a coincidence, NASA's New Horizons wake colleague, en route to Pluto.

Rosetta and Philae in search of organic molecules

According to the DLR , the instrument COSAC , which analyzed some of the gas from the floor of the comet discovered a series, said at a press conference Ekkehard Kührt, Editor responsible for Philae to the DLR. In itself, the information is not surprising since, firstly, the lander's instruments functioned properly and, secondly, Rosetta had already identified organic molecules with Rosina (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis).

In September, in fact, this spectrometer detected from water, carbon monoxide (CO), carbon dioxide (CO 2 ), ammonia (NH 3 ), methane (CH 4 ) and methanol (CH 3 OH). One month later, the instrument highlighted other molecules: the sulfide of hydrogen (H 2 S), hydrogen cyanide (HCN), sulfur dioxide (SO 2 ) and carbon disulfide (CS 2 ). Rosina added to the list of formaldehyde (CH 2 O), a volatile compound that donates formaldehyde in solution in liquid water.

This official list therefore contains only molecules with a single carbon atom but the analysis of the results is far from over. We talk about months at DLR for a full view. However, Fred Goesmann, the Institute Max Planck of Gottingen, told colleagues in Science & Avenir molecules that "at least three carbon atoms" were detected during the analysis of gaseous compounds.

As for the sample probably drawn by the drill, officials of the instrument COSAC say they do not know how much he has recovered. It is still too early to analysis and speculation ...

Philae sniffed organic molecules on its comet

Philae sniffed organic molecules on its comet

The German Space Agency confirmed that the instrument COSAC detected carbon-based molecules from volatile aromas escaping from the tchouri comet. However, the analysis of samples of SD2 drilling has not yet been examined by researchers and the results seem uncertain.

The instrument MUPUS (Multi-Purpose Sensors for Surface and Sub-Surface Science) on Philae, patted the floor of the comet in order to rub the needle.  Despite a gradual increase of the power strokes, the tip has only weakly depressed. Conclusion: there, the ground is hard.  MUPUS also measured temperatures around.  ROMAP (Rosetta Magnetometer and Plasmamonitor) is a magnetometer that could measure changes in the magnetic field during the descent.  A similar instrument (CPP) had done for Rosetta, with the key to the discovery of a strange change in this field.  Converted into sound by a German team of the Technische Universität Braunschweig, she gave an artificial but touching melody.

Examination of the results transmitted by the Philae lander before hibernation continues and the information is provided in dribs and drabs by space agencies have provided different instruments. The DLR (German agency responsible for Philae) has just a small footprint.

The currently most spectacular result was the discovery of organic molecules . This term, which can be confusing, means among chemists molecules comprising a chain of atoms of carbon (or even one). The qualifier is that living organisms of the Earth and build their carbs , their fat , their proteins and nucleic acids. The carbon dioxide (CO 2 or carbon dioxide) and methane (CH 4) are organic molecules.

Millions of bacteria in one kiss

Millions of bacteria in one kiss

The microbiome represents all the microorganisms that live in our bodies, including those of the intestinal flora and mouth, but their genomes and environmental interactions. These microorganisms have more cells than the human body! The composition of the ecosystem present in the mouth varies depending on several factors: age, genetics , diet, but also those with whom we interact, as they can give us some bacteria ... Yes, but how much?

To find out, the researchers asked a member of the couple to drink 50 ml of a yoghurt drink probiotic containing bacteria serving as markers: L. rhamnosus GG, L. acidophilus LA5 and B. lactis BB12 . After 10 s, saliva samples were collected from the person who had been drinking yoghurt. Then the couple had again kissing 10s. New samples were taken from the two partners. Result: the researchers calculated that 80 million bacteria were transferred during the kiss.

A clean kiss humans

The microorganisms microbiome play important roles in our health: digestion of food, synthetic nutrients , prevention of diseases ... They are not all pathogens  ! Or intimate kiss is a characteristic of the behavior species human, as recalled Remco Kort, principal author of this article, "an intimate kiss involving contact any language and an exchange of saliva appears as a single seductive behavior man and are common in more than 90% of the known cultures".

Various hypotheses have been advanced to explain human kiss it would facilitate an intimate relationship certainly, but could also link through chemical information present in saliva, including those from bacterial activity. Information about the "quality" of the partner would then transmitted.

Scary: 80 million bacteria exchanged a kiss

Scary: 80 million bacteria exchanged a kiss

Lovers do not share that feeling, but also bacteria! Researchers have shown that couples who kiss more than nine times a day have similar oral bacterial communities.

If the kiss is involved in a romantic relationship, we know little about its consequences for the oral microflora. This was Dutch researchers wanted to clarify.

Similar mouth microflora within couples

In July 2012, scientists recruited 21 couples who were visiting the Artis Zoo in Amsterdam, 42 people aged 17-45 years. They completed questionnaires about their behavior, such as the frequency of their intimate kisses. Samples of saliva were collected to study the composition of their microbiota oral. The findings appear in the journal Microbiome.

The 10 kinds of bacteria most represented in the oral microbiota were Streptococcus Rothia, Neisseria, Gemella, Granulicatella, Haemophilus, Actinomyces, Veillonella, Porphyromonas and Fusobacterium , which are bacteria normally present in the mouth. The researchers observed that the microbiota of the dorsal surface of the tongue is closer to that of his partner than other individuals. In addition, the results show that when couples often intimately embrace their microbiota salivary become similar.

An already high level of accuracy

This system is designed to generate the representation mathematical an image in order to identify objects. The second neural network has been developed for machine translation.

Some examples of the results obtained by the image description of software Google when different tests. The columns from left to right classify descriptions from the most accurate full off-topic.

An already high level of accuracy

Once the two associated networks, the first will somehow detail an image and transmit a mathematical description of what he sees in the second, which is used to produce a natural language sentence. Google led the system by feeding thousands of images with descriptions written by humans. Then the technique has been tested with several databases of images, Flickr, SBU and Pascal.

In the scientific article that describes this project ( Show and Tell: A Neural Image Caption Generator ), Google engineers deliver the results of the various tests that reach for some, the score of 59% while the rate is 69% for humans. If the first figures already show a high level of efficiency and accuracy, the room for improvement of the system is still important. The development of this dual neural interface depends on the quantity and quality of the material provided to it to learn. "  As databases tailored to the learning of image descriptions will grow and mature, it will be the same for the performance of this kind of approach , "says Google.

A Google software to describe a natural language picture

A Google software to describe a natural language picture

Google has developed an experimental software that knows accurately describe an image from the first analysis. This tool based on double neural interface could be used to generate voice captions to help blind people, but also be used to transmit data in areas where mobile connections are too slow replacing images with text.

"Two pizzas raised above the stove's oven." This is the subtitle automatically generated by Google software after analyzing the image.  The system combines two neural interfaces, one analyzing the image to produce a mathematical description then passed to the second, which would translate as text.

" A picture can be worth a thousand words, but sometimes the words are useful.  "This is the opinion of the researchers working for Google , which created a software capable of accurately describe a natural language image. Still experimental, this system already achieved promising results and suggests several kinds of applications practical. This could include helping visually impaired people to understand a picture with subtitles statements aloud. It could also be used in some areas of the world where mobile connections are too slow to display images on the screen by replacing the text.

Finally, this technology could work in reverse and facilitate image search in natural language via Google . Google's system combines two neural interfaces that originally were developed separately. One of them is a "  deep convolutional neural network  "that the American giant already uses in its Street View service to recognize the street numbers.

Intervention in utero protects baby

Spina bifida is caused by incomplete closure of the neural tube during embryonic development.  Some malformed vertebrae remain open.  A portion of the spinal cord may then exit the spine.

Intervention in utero protects baby

In addition, through fluid leakage cerebrospinal, "this malformation has consequences on the brain fetal whose posterior collapses gradually during pregnancy. Brain effects can then compromise the development of the acquisitions of the children". However, "many studies have shown that prenatal repair of this malformation carried around 5 months pregnant possible to reduce the disability of these children by protecting the spinal cord, which improves motor control legs", says Professor Jean-Marie Jouannic of Armand Trousseau Hospital, AP-HP.

"This operation consists in covering the externalized spinal cord repairing a shell suture that normally covers it and then sutured to the baby's skin , he explains. Compared to care after birth, profits are more important. This remedy helps stop leakage of cerebrospinal fluid. The brain is well protected, the intellectual development of children has improved.

However, this procedure is not without risk. It exposes a birth premature and needed a Caesarean section. However, "this one is a big step for children with spina bifida and their moms. It opens the way for better support and improve thereafter the motor and intellectual development of these children, " concludes Professor Jouannic.