Lycée Blaise Pascal Rouen

Interviews with our foreign visitors and penpals

C. Reymond, Chloé G. — 2014-06-10T14:20:31Z

Now, we are surrounded with English : it's present everywhere, in every form. The question that comes up to my mind is what does English bring people, and what points of view do they have about France ?
To answer this question, I decided to ask my pals Luis, from Spain, and Christina, from China, plus our English-speakers assistants, Pascale, from Canada, and Pierre, from England.

How do they deal with English ?

Pascale was raised with both English and French. In her family, both languages were spoken and because she lives in the English-speaker part of Canada, she had to use English in everyday life. Pierre moved to England when he was young, but before he was living in France. When he first moved to England at the age of 9, he really struggled to learn English. He learnt it very quickly by reading a lot of books and got used to watch the news a lot to pick up the English language.
Luis thinks he can defend himself with English if needed, but maybe not in a serious speech or conversation.
Finally, Christina learns English at school, mostly by exercising, reciting words and working on grammar, and she likes watching movies in English and listening to songs in English. She likes English itself more than her English classes, because from her point of view, China's English classes are really boring, concentrating on exams, and most of the students hate English.

What do they prefer with English ?

For Luis, it's a difficult question to answer, but in general, he likes its internationality, not only chatting with people from all around the world but the ability to read many things and learn technical stuff in English. Quite the same for Christina, who likes listening to songs and watching films in English, and she also likes communicating with people.
Pascale also likes the internationality of English, and as most people learn it as a second language, it's very easy that's why people who speak English are very lucky to have the ability to travel to many countries, for example she has been to many places in Europe, and English seems to be the language of communication, but some people refuse to speak English in countries such as Germany where most people understand and speak English but they don't want to do it. Today, we can have both academic English at school, and spoken English with all that we can access with the internet. Pierre guesses it is the way we speak. Because it's very easy to speak to someone in English nowadays, and in England you don't really mind with verbs and accents.

What do they think English brings them ?

English can bring a lot to everyone. From Christina's point of view, English brings her more than Chinese because it's more interesting to her, it helps her understand more about many things and it has been the key for both of us to meet each other.
Pascale focused on the fact that we have everything in English now, even posters here in France can be written in English and translated underneath. Both Pascale and Luis think English gives us the ability to travel everywhere.

When I say France, what's the first thing they have in mind ?

To this question, the answers are varied. A blue and green world for Luis, because he often sees the things in colors, and the first images he has is a green landscape, also Paris and bohemian lifestyle. Paris is also one of the things Christina has in mind when thinking of France, and also the Eiffel tower and romantism, with no order.
When I say France, Pascale thinks of the shape of the country, the flag and all the stereotypes such as the baguettes, the umbrella, a little cigarette and the hats, also scarves, because many people wear scarves in France, but in Canada only women do wear scarves. That was a culture shock for her when she arrived and saw men wearing scarves, but for her, it's lovely. She also thinks of metros and trains, because they don't have it very much, but it's very common in Europe.
Pierre, who's been living in France, tends to think about the place where he used to live in, which was in Villepinte, Paris and he sometimes thinks of his school life there.

What's their point of view about France and French people ?

Christina thinks France is a beautiful country, and romantic with a long history. She thinks it is now a livable country. For her, French people are romantic, polite and handsome.
Pierre has always loved France, because nothing makes France what it is today without French people. He loves the French culture and he promotes it in England (though not a lot of his friends like that, and some may think that he may be “biased” because he was born there). He thinks that France is definitely a beautiful country with a lot of inspiring people, attracting cities, delicious food, and much more !
A good question for Pascale, who thinks French people are absolutely lovely, and those stereotypes such as French people being rude are false. Many people she talked to were very charmy, very welcoming, very sweet, and really helpy if you need it. In some places in Paris, they were a little bit rude but generally people are nice. There's a good fashion in France too, but she mainly thinks it's a beautiful country, where every region has a bit of a difference. For her, France is a place full of culture, rich in history, and it was easier for her to kind of integrate because she speaks French (compared to other assistants who don't speak french, so it's difficult for them to get settled in the country).
Unlike Pascale, Luis thinks French people and especially Parisian people are snooty and haughty, proud of themselves, etc. But more generally, for him, many countries in Europe speak English, but countries like Germany, Spain and France have a strong identity, and don't speak that much of English, so they don't seem open-minded.

What have they done in France or what do they want to do there ? And why ?

Pascale has eaten a lot of baguettes and pain au chocolat, and has visited Lille, Nantes, Montpellier, and Paris many times, mostly for the touristic places, and took a lot of expressos (which are really different from Canadians coffees). She as visited many places and museums, and she would like to go to Paris more, to visit not only the touristy things but also the local things. Moreover, she would like to try French cheese next time.
Christina loves French and different cultures, so she would like to study and live in France or Canada, such as Luis. He too has been to Montpellier a long time ago, for a school exchange, and maybe in French places near from the border with Cataluña.
Pierre haven't been in France since 2011 but he doesn't think he has done anything interesting, just living there, going on school trips, played outside, etc. However, he would like to visit more the country and maybe get settled here.

To conclude, what are the main differences between France and their respective countries ?

Culturally talking, Spanish people have an inferiority complex, but French are rather pride. And in general, Spanish people are more conservative than French. Christina is clear : France is more free, more democratic, more developed, more clean, and more polite than China. Pascale found similarities and differences, and she likes the fact that there's always something going on in France, that people always walk around in the streets and use public transportations naturally (and it is the case in Europe in general), which is not the fact in Canada because of the size of the cities, and the culture of living in the surbubs while working in the major town, so everybody has its own vehicle and the public transports are not so developed. This is the major difference. There are two more from her point of view : “la bise”, typically French, very surprising at first sight but sweet, and the fact that quite everybody wear scarves, meanwhile in Canada, only women wear scarves, so it made a kind of culture shock when she saw a man wearing a scarf for the first time.

Can NekNomination become something good?

C. Reymond, Jeanss — 2014-06-10T14:20:18Z

NekNomination

• Neknomination is an online drinking game. The concept is simple but not without risks. The original parameters of the game require the participant to film themselves drinking a pint of an alcoholic beverage in one gulp and upload the footage to the web. The participant then nominates three others of his friends to do the same. The nominated person has to complete the task within 24 hours. The objective is to maximize the sharing of the video on Facebook or Twitter. And originality bonus! For example: drinking on the surfboard, in an aquarium, disguised as Batman or as drag queen, in the shower and even driving the car.
• The game became popular in early 2014, thanks to social media like Twitter or Facebook for proof the hashtag #neknomination was used more than five million times in 3 months on social networks. Some education's professionals lead it to cyberbullying because the people who do not take part are shamed. There's a huge amount of peer pressure involved that's certainly been a factor as to why it has escalated.
• This game was launched in Australia and today toured the world. These are mainly young people who play it but not only…
• However, this fad is already responsible for at least five dead. It is time to stop it, the problem is in spite of that some pages were removed, warning messages published on the Internet, or testimonies from parents devastated by the loss of their loved ones due to this game, as Patrick Byrne's plea on facebook, he is an Irish men who lost his little brother after he was neknominated on Facebook or as moving farewell message of Niamh Murphy who lost her boy friend an Irish DJ of 22 years-old after he reportedly playing "nekNomination" , nothing works, this game is still the game of fashion.

– Hope was born with Brent Lindeque, a South African who was neknominated by a friend but decided to turn this game into something more intelligent. Brent filmed himself distributing food to a homeless person, at the end of his video he nominates three of his friends to do the same, he later explained in an interview: “In south Africa, we-have poverty problems and hunger problems, that 'was my first thought of being. My second was I wanted to be more responsible with what I'm posting online ". A week and a half ago it has-been viewed more than half a million times.
– His idea has functioned so well that thousands of other people are put in. In France, at Bordeaux a young boy of 23 years-old, Julien Voinson, was filmed buying hamburgers and some water for distribute them to the homeless. His video was shared a thousand times also and caused positive reactions around the world.
– This new phenomenon is named # smartnomination.
– Now, let's hope that people will forget the neknomination and only practice the smartnomination. We already note a decreased of neknomination in popularity, it must go on!

+ For my personal experience, I knew this game thanks to my English friends. We met each other through the Comenius project of school. They come from St. Joseph High School in London. After they came to visit our school in october, we remain in good contact all together. In November, during our trip to London I got to know some of their other friends. They are really nice. And as of today we are still good friends, we help each other for our language's homework. All this to say that one day I'm falling on a video of one of my friends. He filmed him-self handing food to the homeless in his neighborhood. When I congratulated him for his action, he explained to me what the smartnomination is and that was a smart version of neknomination. He also taught me that many of his friends attended the smartnomination, I was really impressed because none of my French friends participated unlike to neknomination. He asked me if I had ever been nominated for one of his games, but this is not the case, he told me that it was a good thing for neknomination, but I could take my own initiatives and participate in smartnomination. I love his way of thinking, he told me that now people have to understand that they can help others without having to participate in a game.

◊ Other initiatives also take place and become viral, like giving a big tip to a waiter/waitress. Before dying, Aaron Collins, asked his family to leave "an awesome tip" to a waiter and “not a 25% tip, but $500 on a pizza for a waiter or waitress”, he specified. Today all his family, his brother in particularly, Seth honors his last wish. Last year, Seth Collins set out to give $500 tips to waiters and waitresses in all 50 states. So far, he's given out 54 tips. He hopes to reach 100. This movement is filmed and put online. It receives a lot of view and messages of sympathy. He created a Facebook page "Aaron's Last Wish" which permits to him to raise money to continue his duty to his brother. Each surprising tip has also helped the Collins family cope with their loss.
http://www.huffingtonpost.com/2013/07/03/seth-collins-500-tips-in-each-state_n_3541891.html

 All these initiatives are at the origin of a single person and through social networks are much more extents, even global. Some have much more merit than others, just as some are more interesting. These initiatives are called viral, due to their fast distribution and of the interest which arouse in world.

How does the bridge to join Ásgard form?

C. Reymond, Jeanss — 2014-06-10T14:19:38Z

The Rainbow

(Pour expliquer la problématique: In Norse mythology, the rainbow named Bifröst is the "bridge" which provides access to Asgard, the realm of the gods, guarded by the god Heimdall. Men were always fascinated by the rainbow, it is found in many other mythologies [example: • In Greek mythology, the path between heaven and earth was created by the messenger of the Olympian gods, Iris. She used it to bring messages from the gods to mortals. • For the ancient Irish, the secret the hiding pot of gold of the Irish leprechaun was where the end of the rainbow sky is. The leprechaun won his gold by making fairies' shoes and keeps it in a pot that he hides preciously. The rainbow shows humans where the leprechaun's pots are, however it is very rare to be able to catch, the leprechauns are very clever. • It also evokes Buddha's enlightenment, who descends from the sky by this staircase of 7 colors, the ramps are 2 snakes ...)

• A rainbow is an optical and meteorological phenomenon that makes visible the spectrum of light from the sky when the sun shines when it rains. Although a rainbow covers a spectrum of continuous colors, we can distinguish several significant colors red, orange, yellow, green, blue and purple.

How does it form?

• The light emitted by the sun is "white", that is to say it consists of a kind of mixture of light waves of different wavelengths like red (which corresponds to a wavelength of 620-780 nm), orange (592-620 nm), yellow (578-592 nm), green (500-578 nm), blue (446-500 nm) and violet (380-446 nm). If this white light is decomposed into its constituents, the spectrum of visible light is obtained. (This decomposition occurs during the phenomenon of diffraction.)
• But when it rains, each drop of water produces diffraction: it reflects the white sunlight into its various components deviating at different angles. Thus appear seven colors
• The rainbow is caused by the scattering of sunlight by approximately spherical drops of rain. Light is first refracted by penetrating the surface of the drop, then subjected to a partial reflection on the rear of the drop and is refracted again when it comes out. The overall effect is that the incoming light is mainly refracted rearwardly at an angle of approximately 40-42 °, regardless of the size of the drop. The precise value of the angle of refraction depends on the wavelength of the components of light (for example: 40 ° in the case of purple).In the case of entry in a more refracting environment, the refractive angle of the blue light is lower than that of red light. Thus, after reflection on the water-air interface, the blue light emerges from a drop above the red light (the blue light is reflected at an angle of 40.5 ° with respect to the sun's rays, and the red light at an angle of 42.4 °).
• And it is the reason why, if you want to see a rainbow you must wait until the sun is located below 42 °, because this is the only opportunity for you to see it. It is most unlikely to observe one at noon, because the sun is higher than 42 ° so the colors cannot be seen from the ground. Conversely, the lower the sun is on the horizon, the higher the rainbow is. But you will never see a full semicircle, unless you are in the mountains or in an airplane. In the latter case, you can even see the whole circle.
• Furthermore, according to the drops size, the rainbow is more or less colored. Indeed, very fine droplets scatter incident light badly, therefore the rainbow will be very pale.
• Because the observer is fixed and turns his back to the sun, he sees light from water droplets with different angles relative to the sunlight. Therefore a rainbow doesn't actually exist physically but is an optical illusion whose apparent position depends on the position of the observer and the sun, the center of the rainbow is exactly in the opposite direction to Sun's relative to the observer. All raindrops refract and reflect the sunlight in the same way, but only the light from a small part of raindrops reaches the eye of the observer.
• It is the image formed by the light of these raindrops that we see as rainbow.

Some possible questions:

Why do we see rainbows so frequently in summer and almost ever in winter?
To observe a rainbow, there must be sun and rain. In winter, the droplets of water freeze to form ice particles which do not produce rainbows.

Why rainbows are so rarely observed at noon?
Don't forget that the center of the rainbow is opposite to the Sun. At noon, the sun being very high in the sky, the rainbow is thus far below the observer.

Do two people see the same rainbow?
Humphreys, a famous researcher, indicates that «because a rainbow is a special distribution of the color (produced in a particular way) with respect to a well defined point - the eye of observer - and because a single distribution cannot be observed by two different points, it follows that two observers do not see, and cannot see, the same rainbow. » In fact, each eye sees a different rainbow!

Do you, as J. Gatsby did, believe in the green light ?

C. Reymond, Chloé G. — 2014-06-10T14:19:05Z

What's a green flash ?

A green flash is an optical phenomenon, such as a mirage, but it is not an optical illusion. You can see it at sunset or sunrise. It is a sudden moment (it does not last more than one second or two), when a part of the sun suddenly changes color from red/orange to green/blue so that's why we describe it as a flash due to the ability of the air to separate the colors of the light. It is a rare phenomenon, and we can also observe it with the moon. It usually occurs on the horizon, when it is unobstructed : if there are clouds, ships, haze or anything that can avoid you to clearly see the horizon line.
It is so sudden that when I had the chance to witness one, I didn't see it, actually I was taking photos of a sunset in Mauritius and it is only when I watched my photo afterwards that I realized I had caught a green flash.

The different kinds of green flashes

If you project the telescopic image of a the sun ready to set, about 10 minutes before it disappears, you will be able to see the upper and lower limbs of the sun (in astronomy, the limb is the apparent contour of a star). The lower half of the limb will appear red, and the upper half of the limb will appear green. But it's difficult to see it, because even in the best conditions, the green and red limbs would be very tiny. Thus, it cannot be seen with the naked eye. This phenomenon is named the green and red rims (rim is usually used for the outer edge of car wheel or the edge of an object).
However, there is a unique phenomenon allowing us to see a green rim flash with the naked eye : the elevated horizon flash. It can be seen when the lower rim is occulted by an elevated obstacle such as a mountain, or even a skyscraper. In that way, the upper rim is isolated, and we can see it. Furthermore, it has a chance to appear blue or violet.
The green flash commonly appears in two forms : as a flash, when the green spot is rather extended, or as a dot.

Why is the green flash green ?

Firstly, green flashes can also be yellow, blue, violet, etc, but green is the color we most often see. The atmospheric dispersion is the cause for the color. Indeed, the refraction changes a bit according to the color of the light, and dispersion is the variation of the refractive index with the wavelength of those colors of the light. It is a refractive property of all transparent media : they all are dispersive. And so refraction by the air is larger at shorter wavelength. And then, while the sun sets, the refractive delay of the colors is usually longer for blue (wavelength : between 430 and 380 nm) and violet (wavelength : between 500 and 430 nm) than for red (wavelength : between 740 and 625 nm).
In fact, the colored images of the sun disappear from red to violet (red-yellow-green-blue-violet). Dispersion is usually small enough to be negligible, and it is visible only in special situations.
However, the green flash should be violet, because it is supposed to be the last color seen at sunset. So why do we see it green ? Here is another phenomenon in cause : the atmospheric extinction, or how the wavelength are scattered. When light passes through a medium not perfectly homogenous, such as air, the light is scattered in all directions by the medium's irregularities. Air molecules are large enough to scatter the light, and the shortest wavelengths are scattered most strongly (the best example is the blue color of the sky : blue light has got a short wavelength, so is it strongly scattered, and the blue rays go in all directions, therefore we see the sky as blue).
On the horizon, the path from the air to the observer's eye is very long, so when the light comes toward your eye, the shortest wavelengths are almost completely removed. And usually, there is enough haze in the air to totally remove the violet and blue colors, so that the last color to be seen is green, or, if the green flash occurs at sunrise, green would be the first color to be seen.
Even the yellow color disappears when you see a green flash. If you look at the sunset, the red-sensitive receptors of the retina would be affected, and for a while, the color perception is slightly changed without you being aware of it. It comes out as seeing the yellow part of the visible light at sunset as green. This effect can be avoided by observing green flashes at sunrise, but it is difficult to guess where the sun is going to rise before it's there.

The Green Flash

The green flash I caught in Mauritius, on 2012.

What is the destiny of a frog eater in the Far West ?

hemeryi — 2014-03-19T13:36:50Z

My first presentation will by on an international topic, so I am going to tell you the story of my extraordinary trip
in the USA.
first I've made a contact with the family who would host me. After a couple of e-mails and many phone call
they told me that they would be very happy to accommodate me in their home. Note that I didn't ask an organization to find a family for me , I wanted to do my own trip !
To tell you all, my host family is a longtime friend of my family. My Mom met them twenty years ago.
What's nice is that they have three children and one boy is nineteen years old like me, so we were partner
all along my trip.
To start with, I've flown for 10 hours to reach Seattle and finally discover the United-States, but, in spite of my enthusiasm I could not do my first activity on this day because the length of the flight and the jet lag were too tiring for me. During my trip I've done many fun
activities, like fishing , diving and playing typical sport (baseball & football), but I believe that the two greatest
outings were the baseball game ( Seattle Vs Torronto ) that I saw in the huge Safeco fields, and the hiking trip to
Mount Rainier. Beyond these activities, I've discover the American spirit and I've made the acquaintance of many people who were very friendly with me, for example , when I was speaking in the street with a member of my host family, someone who heard me speak, asked me where I came from , because my accent sounded funny to them. Later, I've visited the Museum of Flight, and it was an enjoyable moment to see the evolution of plane history, moreover this museum has one original Concorde plane ( there remains only 18 of them in the world ) and I got on this fabulous plane. Apart from that, I often went to Bothell with the younger son to meet his friends to laugh and play soccer near the Washington lake. what's more when I had more time I went to Seattle, which is very difficult to do : to go to Seattle we took the bus or we hitchhiked. Once in Seattle we went to the city center to see the space needle and the downtown buildings , it was so impressive that it was mind blowing ! The feeling when you're in a country where nobody speaks your language is weird, nonetheless it's pleasant when you begin to think in English, because that means you progress. These three weeks very far away from my family made me indepedent, moreover this experience showed me that I can get organised and I now think that could live in another country when I am an adult.

Is UAV the future of military aviation ?

P.Gutierrez — 2014-03-19T13:35:50Z

● Is UAV the future of military aviation ?

Introduction

First, what is a UAV ? It means "unmanned air vehicle".
This term is used to refer to military combat drones. These aricrafts have no on-board pilot. Operational drones are predominantly under real-time human control, according to the levels of autonomy of the UAV and data communication. The pilot (also called operator) is based at the air field, in a specific section, which looks like a real cockpit.

I will develop two mains parts that are going to deal with the history, and the specific use of UAV.

History

The first explorations of the concept of combat drone were made by Dr. Lee DeForest (the inventor of radio devices) and U.A. Sanabria (a TV engineer). Their idea of combat drone was published in a 1940 publication of Popular Mechanics.
The modern military drone as known today is the brainchild of John Foster Jr., a nuclear physicist. In 1971, Foster was a model airplane hobbyist and had the idea that this hobby could be applied to building weapons. He drew up plans and by 1973 the DARPA (Defense Advanced Research Projects Agency) built two prototypes called "Praeire" and "Calere", powered by a modified lawn-mower engine which could stay aloft for two hours while carrying 13kg of load. (this 13kg of load could be used to carry weapons, for example)
In the late 80s, Iran deployed a drone armed with six RPG-7 in the Iran-Iraq war. This was the first time that an armed drone was used in war.
The first "UAV war" was during the first Gulf war. After the Gulf war succesfully demonstrated their utility, armies throughout the world invested widely in the domestic and military development of UAV (so UCAV, C for combat).
In recent years, the USA have increased their use of drone strikes in Pakistan as part of the War on Terrorism.

Specific use UCAV

These types of airplane are mainly used for tactical missions (spying, aerial survey, etc.), but also for strategic bombing if used in war countries.
Drones can fly alone and can achieve some results through their own autonomy system : flying from point A to point B, detecting intruders, vehicle's movement on the ground, detecting other airplanes, etc...
However, even with all these qualities, UAV are not 100% autonomous : they need an operator (=pilot) to achieve some precise stages in a flight like taking-off, dogfighting (= specific term for aerial fighting) (if necessary), taking into account weather conditions, and landing. (dire aussi à quelle distance l'opérateur doit /peut être de l'engin, en km…)
Because the operator isn't in the drone, but at the airbase, there is no equipment for a human pilot inside the drone : no seat, no system to bring oxygen to the pilot, no flight instruments, no cockpit, no ejection system, etc. This result in a lower weight and size than for a equivalent manned aircraft. This can allow for greater payloads, load factors, range and maneuverability.
As an example, in 2013, Boeing retrofitted multiple Lockheed Martin F-16s (pas d'apostrophe) (called QF-16) with UAV technology. The company demonstrated combat maneuvers including barrel rolls, a Split S and a perfect center line landing. During the test flight, the QF-16 cruised at 12,000m and reached A speed of Mach 1,47 (1500 km/h). The aircraft reached a 7Gs load factor, but is expected to regularly operate at 9Gs.

UAVs typically fall into one of six functional categories :
Target and decoy – provides ground and aerial gunnery / a target that simulates an enemy aircraft or missile
Reconnaissance – provides battlefield intelligence
Combat – provides attack capability for high-risk missions
Logistics – UAV specifically designed for cargo and logistic operation
Research and development – used to further develop UAV technologies to be integrated into field deployed UAV aircraft
Civil and Commercial UAV – UAV specifically designed for civil and commercial applications
UAV are also categorised according to their range, and the altitude that they operate. Altitude could be between 5000m and 20000m, autonomy can be up to 40hours. UAV can also be stealth.

UAV are equipped with remote sensing functions that include electromagnetic spectrum sensors, gamma rays sensors, biological and chemical sensors (use of laser spectroscopy to analyze the concentrations of each element in the air). So that it is possible to find thermal imaging or infrared cameras aboard a UAV.

Conclusion

UAV is a new technology that has made significant progress in the last few years. After the first Gulf War, UAV showed that they are essential in today's conflicts. This will soon mark a turning point in the next mitlitary actions where UAV will be the key of the success.
As far as aviation is concerned, UAV will renew the way airplanes fly usually, because drones are lighter, and there is no pilot inside anymore...
Flight domain will be soon limited by the machine and mechanical laws and not by the pilot's capacities to accept high load factors.
Nowadays, regular airlines plane's could fly without on board pilot. The only limiting factor is that people who are in the plane are not ready to fly without pilot abord yet, so this is an economic reason. This isn't a technogical reason anymore...

What happens when French people are lost in the USA?

C. Fosse, C. Reymond — 2014-03-19T13:34:43Z

Social differences in everyday life in the USA and France

What happens when French people are lost in the USA?

France and the USA are often considered as a similar part of the occidental world, but their peoples have sometimes dissimilar behaviors in their everyday life. The way they live and the feelings they give to the others are very different and specific to the country.

The American society is the self-made-man society, and this shows that it is more important for American people to develop their lives instead of just living it as in France. American people take from France what they most desire and in return, French people take what they need from the USA. Those beneficial exchanges are the basis for a productive relationship between France and the USA. Nevertheless, if each country is interested in the other, it is true that there are differences between them. People feel those differences without having them in mind, because they have grown up in two different societies and past and recent histories and societies make French and American people think differently.
An example of the back and forth exchanges is that hip-hop music was born in America and then transmitted to France, where the first show only made for hip-hop was created in the 80s. And yet French hip-hop artists do not copy American artists but have created their own hip-hop music, which is now a part of the French culture. Even if people mark cultural practices as French or American, this shows only the concerns of a given moment. One of the differences between French and American people you can easily see is the way to say hello. In France, the most common way with friends is to greet them with a “bise”, which involves alternately pecking the friend on each cheek up to four times, in the USA the most common way is a handshake. American natives recognize quickly foreigners, and as part of them, the French by what they call the French je-ne-sais-quoi.

I made a trip with my family from New York to Chicago last year. Everywhere we met people who were ready to help us or just to chat with us.
In big cities like New York and Chicago, each time we stood on the street looking for a shop or a road sign someone came to us asking if we needed help. Once we were standing in the stairs of a subway exit, and a man thought we needed help whereas my father was just taking a photo. Another time, a man helped us find a fast food restaurant while he had just arrived in the city for his job and did not know it. Last, one evening as we were coming back home late, we went out of the subway by an exit we did not know and did not recognize the neighborhood. A black man saw us and explained how to go home without passing though a park, which was not recommended for white people at 11:00 pm in Brooklyn.
In a small shopping center lost in the middle of nowhere, we had breakfast in a fast food. Two grannies and two grandpas were drinking coffees. One of the grannies came towards us to chat and learn more about the strangers she had not met before. The most incredible was that she had not suspected that we were not American.

All the people who helped us or with whom we chatted were American. Actually, they naturally came towards us at any time and anywhere. I thing it is the major difference we can see between France and the USA when standing in the street : in the USA people are more open, receptive and attentive to others than in France, where people sometimes give help only if someone asks them for it.

Smoke alarms

Jeanss — 2014-03-19T13:19:32Z

How can we prevent a family from dying in the fire of their house ?

In France, there are about 12,000 victims of smoke inhalation from fires per year.
So a law has been passed in 2010 in France, making smoke detectors mandatory in all private housing by March 8, 2015.
There are three different types of smoke detectors, the most widespread in the world are :
– The optical or smoke detector
- The ionization smoke detector, which is banned in France especially because it contains a radioactive source.
– The linear smoke detector.

Optical sensor

The photoelectric (or optical) smoke detector is the only type of detector authorized in France. It is the newest and best suited for home fires as it reacts to slow progression fire that may smolder for several hours before we can see the first flames appearing. These fires with slow evolution are also the most many and the most dangerous (for example : A fire caused by a cigarette, ... ) . These sensors are composed of a light emitting diode (LED), an optical chamber, and a photocell. When the smoke reaches the smoke detector, the diode emits a light towards a photocell which in turn produces a current which triggers the sound alarm.

Ionization detector

This sensor consists of two electrodes together with a radioactive element, Americium 241 which gives out alpha radiation. The alpha radiation ionizes the air inside the alarm, and a current flows. If there is smoke in the room, the smoke absorbs the radiation, no current flows and an alarm sounds. Because of its dangerous radioactive element (Americium 241 : a silvery highly electronegative metal. It is part of the actinides family and oxidizes rapidly in the presence of oxygen. It is a compound that is deposited mainly in the skeleton, liver and gonads. The recommended treatment in case of contamination by Americium is the administration of DTPA -diethylene triamine pentaacetic acid-, it is now banned from sale to individuals. ). This is the oldest type of smoke detector, it has existed for over 50 years. It is especially effective for fire with flames. Many European countries prohibit the sale of these detectors because even if very small, they contain a radioactive source. These ionic detectors are banned especially in France.

Linear smoke detector

This sensor operates on the principle of light absorption. The sensor sends light pulses that are reflected by a reflector. The detector measures the level of the reflected signal. A decrease in the signal means a presence of smoke.

Locations

For optimal use, it is advisable to put at least one per floor, and to place them at least near the bedrooms and the kitchen. The presence of a detector inside the kitchen can lead to false triggering with simple cooking vapors. It must be placed on the ceiling, about 50 cm away from the entrance of the room to be efficient.
In the presence of smokers, it can be useful to put one in the bedroom, on the ceiling, near the entrance.

A smoke detector is very important for the safety of the inhabitants of a house. They require very little maintenance and are available at very low cost today. Prices may vary from 15€ for the least successful to 100€ for more sophisticated. Its presence will be required, by insurances from 2015 in France, to hope to be compensated after a disaster.

Record of americium-241

Name : Americium Dioxide
Appearance : Solid black crystalline
Empirical Formula : AmO2
Molar mass : 275g/mol
Melting temperature : 1000°C
Insoluble
Density : 11.680kg. m-3
Radioactive Compound

S.J.

What do you obtain in combining the Incredible Hulk and Cerebro?

C. Reymond, Chloé G. — 2014-03-13T16:04:42Z

Gamma knife was invented by Lars Leksell in 1967 in Stockholm. It consists in a helmet delivering gamma rays from ionized Cobalt 60 in 201 rays coming together to the brain tumor we want to destroy.

About Cobalt 60

Cobalt 60 is derived from Cobalt 59, a stable isotope of Cobalt. It decays in Nickel 60 by a beta minus reaction. It has a half-life of 5,27 years. One of the inconvenient of Cobalt 60 is the requirement to clear out every 5 years from a very radioactive source (in fact, even after those five years, the cobalt stays radioactive, even if half of the atoms had decay), able to cause accidents and it can fall out in dusts. Cobalt 59 can be used in a nuclear bomb to give Cobalt 60, which would infect the place, becoming uninhabitable for decades.
Cobalt 60 was widely used in radiotherapy, but now we tend to use linear accelerators (also called linacs) to have a best control and not the disadvantages of cobalt. Those accelerators emit X-rays by accelerating charged particles to give them an important amount of energy. This kind of accelerators uses linear successive accelerations to induce energy. But those linacs are no longer used in radiotherapy today.
The fact is that, in a simple point of view, gamma rays have 1000 times more energy than x-rays. Both are electromagnetic rays but they have different frequencies (gamma ray's is higher: more than 1020 Hz against 3x106 Hz for X-rays) . But in a more technical explanation, if we take the electromagnetic Spectrum (EM spectrum), we can reach a point where gamma rays and X-rays are identical in EM properties, including in the energy. At this point, the only difference is the origin of the ray. The x ray comes from the electron shell of an atom, and the gamma ray comes from its nucleus. The first one originates from an over-excited electron, moving up in the layers. But it wants to come back down, so it emits energy in x ray. The second one comes from a nuclear reaction on an atom, something which excites the nucleus, as an alpha reaction, a beta reaction, a fusion or a fission.

The treatment

During the treatment, the patient wears the helmet and it delivers a higher and higher dose of gamma rays. Using the coordinates, the nature of the rays, their energy and the thickness of tissues to go through, we can see with a computer where the highest dose should be delivered. In fact, we have a total control of the operation and the precision is allowed by today's level of technology. Moreover, to avoid a dangerous irradiation, the entry points are multiplied to send less radiation on a larger zone of healthy cells with short times of exposure.
The great advantage of the gamma knife is the limitation of the risks of hemorrhage and infections. Moreover, it just takes a 10 minutes session to destroy a tumor, there are neither cranium opening nor anesthesia, and the visualization is simplified, even though the patient could suffer from headaches after the intervention and the healthy zones are irradiated (in small quantity, but it stays kind of harmful).

Some figures...

Now, there are about 300 gamma knife units in the world, including 6 centers in the UK (they got their first gamma knife in the 1970s), AND more than 100 in the USA. The San Diego center has treated 3700 patients in the last 18 years. The finest unit in the world is located in Marseille.
According to the Leksell Society, over 676,000 patients were treated with the Leksell Gamma knife through 2011, against 7,000 in 1991.
The main concentrations of patients treated by Gamma Knife are in Japan, the USA, Korea and China, and Europe.
Today, the original Leksell Gamma Knife is in UCLA Medical Center in Los Ageles, CA. It was donated in 1982, served for animal research and was used to cure some human patients.

Explanation of the problematic

Bruce Banner was originally a scientist specialized in gamma rays and he became The Hulk by being irradiated with gigantic doses. Cerebro is a tool created by Magneto and Professor X from Marvel's X-men to expand Xavier's telepathy. But the patients cured by the Gamma knife apparently don't become a super violent green monster after being treated!

Thanks to DR. Steve Goetsch, Director of Medical physics from San Diego, CA, USA, and Dr. Maheep Singh Gaur, Director of Gamma Knife Radiosurgery from Noida, India for their kindness and precious informations.

Dr Steve Goetsch and Catherine Gilmore with UCLA Gamma knife.

The first Leksell Gamma Knife, now at the UCLA Medical center, Los Angeles.

To go further...

Here is a simple explanation in the differences between gamma rays and X-rays : http://wiki.answers.com/Q/What_is_t...
A long explanation, more complex : http://wiki.answers.com/Q/What_is_t...
Learn more about nuclear decay : http://edtech2.boisestate.edu/linda...
About the difference between nuclear fusion and nuclear fission : http://wiki.answers.com/Q/Differenc...

Nail Polish

C. Reymond, DORE — 2014-02-19T17:27:45Z

Nail polish is a cosmetic product which protects, conceals defect in the nail and makes it nicer. It's used mainly by women and today, the trend of nail polish has been launched : it's as important as jewelry or clothes for people who wants to be fashionable. We can find a lot of nail polish colors and many brands are on the cosmetic market as luxury brands. But in a traditional nail polish, there are many toxic chemical components because to make nail varnish you need plasticizer agents, solvents, film-forming agent and pigments.

The main chemical plasticizer agent which is used is dibutyl phthalate. It's added to have more elasticity and for the nail polish not to peel off. And yet , dibutyl phthalate is a toxic product which is responsible for foetus malformations and miscarriages but the plasticizer agent quantities in flask are regulated by law.
Solvents like acetone, formaldehyde, toluene and ethyl are added to increase the smoothness and to have an easier application. When nail lacquer is applied, solvents evaporate and cause the smell along with hardening of the nail polish. There are poisoning risks only if you are in contact with a big quandtity of solvents like in manufactures; and yet it causes some effects on the nervous system, the blood (cancers), liver or kidney (cancers or kidneyl failure) and on fertility and pregnancy.
Film-forming agent is the component which form a film on the surface of nail polish and this film protects the nail against outside attack. The main film-forming agent is nitrocellulose but it's a dangerous product because it's flammable even if it's dried. Therefore it must be diluted with a minimum thirty percent of isopropanal.
For colouring, there are natural pigments and chemical synthetic pigments. Some synthetic pigments are derived from aniline, a toxic oil product when it's in pure condition.

An investigation made by the DGCCRF on two thousand shops in France has revealed that ten percent of nail polish and hardeners are outlaw because there was phthalate banned by the law and a formaldehyde (solvent) concentration over than the five percent allowed in it.
There are real dangers because these products can come through the nails and also be breathed in.

In contrast, new categories of nail polish have been invented like 3-free nail lacquers. This nail polish doesn't contain the three main chemical components which can be bad for health : toluene, formaldehyde and dibutyl phtalate. Moreover, in 2001, a new nail polish with water was marketed : the « Suncoat ». It's not constituted with toluene, formaldehyde, phtalate, acetone and its pigments are natural, without chemical synthetic colouring.

See more : http://www.womanjunction.com/topic/nail/ingredients-in-nail-polish/
http://www.ehow.com/how-does_4927067_how-nail-polish-made.html

T. DORE, Mme REYMOND