Por que sonhamos? - Artigo

Sonhar é uma das coisas mais estranhas que acontece com os seres humanos. 

Pesquisas recentes conseguiram evidênciar sobre o que é sonhar.

A hipótese de que o sonho está ligado à vida em vigília foi sugerida por Sigmund Freud no início do século 20.

Deve-se ter em mente que sonhos são de dificil interpretação, uma vez que acontecem inteiramente na cabeça de uma pessoa e no momento em que ela não consegue comunicar com outros.

Para estudar o assunto, uma equipa de pesquisadores do Laboratório do Sono da Universidade de Swansea, no Reino Unido, recrutou 20 estudantes voluntários que passaram  muitas noites no Laboratório do Sono, onde permaneceram monitorados por métodos de eletroencefalogramas não invasivos.

Desta forma, os cientistas foram capazes de observar e registar a atividade das ondas cerebrais associadas ao sono, concluindo que sonhos com maior impacto emocional eram mais prováveis de serem incorporados ao sono do que sonhos tediosos e inebriantes.

Jornal Ciência

Central Lunar Eclipse - Astronomy picture of the day - 2018 August 3

Central Lunar Eclipse 
Image Credit & Copyright: Anthony Ayiomamitis (TWAN)

Explanation: Reddened by scattered sunlight, the Moon in the center is passing through the center of Earth's dark umbral shadow in this July 27 lunar eclipse sequence. Left to right the three images are from the start, maximum, and end to 103 minutes of totality from the longest lunar eclipse of the 21st century. The longest path the Moon can follow through Earth's shadow does cross the shadow's center, that's what makes such central lunar eclipses long ones. But July 27 was also the date of lunar apogee, and at the most distant part of its elliptical orbit the Moon moves slowest. For the previous lunar eclipse, last January 31, the Moon was near its orbital perigee. Passing just south of the Earth shadow central axis, totality lasted only 76 minutes. Coming up on January 21, 2019, a third consecutive total lunar eclipse will also be off center and find the Moon near perigee. Then totality will be a mere 62 minutes long.

Eclipse over the Gulf of Poets - Astronomy picture of the day - 2018 August 2

Eclipse over the Gulf of Poets 
Image Credit & Copyright: Paolo Lazzarotti

Explanation: The total phase of the July 27 lunar eclipse lasted for an impressive 103 minutes. That makes it the longest total lunar eclipse of the 21st century. The Moon passed through the center of Earth's shadow while the Moon was near apogee, the most distant point in its elliptical orbit. From start to finish, the entire duration of totality is covered in this composite view. A dreamlike scene, it includes a sequence of digital camera exposures made every three minutes. The exposures track the totally eclipsed lunar disk, accompanied on that night by bright planet Mars, as it climbs above the seaside village of Tellaro, Italy. In the foreground lies the calm mediteranean Gulf of La Spezia, known to some as the Gulf of Poets. In the 3rd century BCE, heliocentric astronomer Aristarchus also tracked the duration of lunar eclipses, though without the benefit of digital clocks and cameras. Using geometry he devised a way to calculate the Moon's distance from the eclipse duration, in terms of the radius of planet Earth.

Astronomy picture of the day - 2018 August 1 - The Iris Nebula in a Field of Dust

The Iris Nebula in a Field of Dust 
Image Credit & Copyright: Franco Sgueglia & Francesco Sferlazza

Explanation: What blue flower grows in this field of dark interstellar dust? The Iris Nebula. The striking blue color of the Iris Nebula is created by light from the bright star SAO 19158 reflecting off of a dense patch of normally dark dust. Not only is the star itself mostly blue, but blue light from the star is preferentially reflected by the dust -- the same affect that makes Earth's sky blue. The brown tint of the pervasive dust comes partly from photoluminescence -- dust converting ultraviolet radiation to red light. Cataloged as NGC 7023, the Iris Nebula is studied frequently because of the unusual prevalence there of Polycyclic Aromatic Hydrocarbons (PAHs), complex molecules that are also released on Earth during the incomplete combustion of wood fires. The bright blue portion of the Iris Nebula spans about six light years. The Iris Nebula, pictured here, lies about 1300 light years distant and can be found with a small telescope toward the constellation of Cepheus.

Evard Grieg - "Morning mood" - Video - Music

"Morning mood"

Science-Presse - Cancer : contourner les résistances à la chimiothérapie - Médecine/Santé

Efficace sur les cellules malignes qui prolifèrent rapidement, la chimiothérapie rencontre néanmoins des obstacles. Certaines personnes développent une résistance au traitement : les médicaments ne parviennent plus à détruire leurs cellules cancéreuses.

Une équipe québécoise a récemment identifié un nouveau mécanisme moléculaire expliquant cette résistance aux médicaments anticancéreux. Mieux, leur étude montre que ces chercheurs ont réussi à contourner les résistances en rendant les tumeurs à nouveau sensibles à la chimiothérapie.

« La découverte de ce nouveau mécanisme de résistance est prometteuse et nous avons déjà une piste pour le diminuer », explique Claire Dubois, chercheuse en immunologie à l’Université de Sherbrooke.

C’est l’augmentation du taux d’acidité au sein de la tumeur qui développe ce mécanisme de défense contre les médicaments — et dans certaines circonstances, le développe tant et si bien que le médicament devient inefficace. Cela se produit dans un micro-environnement pauvre en oxygène (hypoxie), qui est une caractéristique du développement des cellules malades.

L’équipe de Claire Dubois s’est donc intéressée à ces changements de pH et à l’appauvrissement en oxygène. Une cellule qui pousse dans un environnement aussi hostile doit nécessairement s’adapter — ce que les cellules normales ne parviennent pas à faire, au contraire des « super cellules » cancéreuses.

L’impact de l’hypoxie sur l’invasion des cellules cancéreuses était déjà connu. « Les régions pauvres en oxygène génèrent des structures aberrantes sur les vaisseaux sanguins — les nouvelles vascularisations se forment mal — et augmentent la malignité des tumeurs », rappelle la chercheuse.

En modifiant ainsi leur environnement, les cellules cancéreuses parviennent donc à résister aux médicaments en sur-acidifiant certains de leurs « compartiments » — ou endosomes. En devenant très acides et pauvres en oxygène, elles vont y piéger les molécules du médicament.

Lire l'article complet sur :

http://www.sciencepresse

ESA/DLR/FU Berlin; Bill Dunford - Layers of the South Pole of Mars - Astronomy picture of the day - 2018 July 31

Layers of the South Pole of Mars 
Image Credit & License: ESA/DLR/FU Berlin; Bill Dunford

Explanation: What lies beneath the layered south pole of Mars? A recent measurement with ground-penetrating radar from ESA's Mars Express satellite has detected a bright reflection layer consistent with an underground lake ofsalty water. The reflection comes from about 1.5-km down but covers an area 200-km across. Liquid water evaporates quickly from the surface of Mars, but a briny confined lake, such as implied by the radar reflection, could last much longer and be a candidate to host life such as microbes. Pictured, an infrared, green, and blue image of the south pole of Mars taken by Mars Express in 2012 shows a complex mixture of layers of dirt, frozen carbon dioxide, andfrozen water.

Carlos 'Kiko' Fairbairn - Lunar Eclipse over Rio - Astronomy picture of the day - 2018 July 30

Lunar Eclipse over Rio 
Image Credit: Carlos 'Kiko' Fairbairn

Explanation: Moonrise doesn't usually look this interesting. For one thing, the full moon is not usually this dark -- but last Friday the moon rose here as it simultaneously passed through the shadow of the Earth. For another thing, the Moon does not usually look this red -- but last Friday it was slightly illuminated by red sunlight preferentially refracted through the Earth's atmosphere. Next, the Moon doesn't usually rise next to a planet, but since Mars was also coincidently nearly opposite the Sun, the red planet was visible to the full moon's upper right. Finally, from the vantage point of most people, the Moon does not usually rise over Rio de Janeiro in Brazil. Last Friday's sunset eclipse, however, specifically its remarkable Micro Blood Moon Total Lunar Eclipse, was captured from Rio's Botofogo Beach, along with an unusually large crowd of interested onlookers.

Usine Nouvelle - Le Beluga XL barbote enfin dans le ciel - Aeronautique

Le dernier-né de la famille Airbus, le premier BelugaXL, nouvel avion-cargo de l'avionneur européen, a réussi ce jeudi 19 juillet son décollage, à partir des pistes de Toulouse-Blagnac (Haute-Garonne), pour un premier vol d'essai d'une durée d'environ quatre heures.

Un événement fêté comme il se doit, dans la tradition d'Airbus, en présence de plusieurs centaines de salariés du groupe, de partenaires industriels et d'élus locaux. D'autant que ce nouveau programme s'inscrit directement dans l'organisation industrielle de l'avionneur européen.

Ce nouvel avion-cargo, successeur de l'actuel BelugaST (mis en service en 1994), doit accompagner les montées en cadences de production de l'A350 XWB et des avions mono-couloirs d'Airbus. Sa mission est d'assurer, comme pour son prédécesseur, le transport d'ailes et de tronçons entiers de fuselage entre les différents sites industriels d'Airbus en Europe. "C'est une pièce maîtresse dans l'organisation industrielle du groupe", insiste Bertrand George, directeur du programme chez Airbus.

ESO/MPE/Nick Risinger (skysurvey.org)/VISTA/J. Emerson/Digitized Sky Survey 2 - Journey to the Center of the Galaxy - Astronomy picture of the day - 2018 july 29

Journey to the Center of the Galaxy 
Video Credit: ESO/MPE/Nick Risinger (skysurvey.org)/VISTA/J. Emerson/Digitized Sky Survey 2

Explanation: What wonders lie at the center of our Galaxy? In Jules Verne's science fiction classic A Journey to the Center of the Earth, Professor Liedenbrock and his fellow explorers encounter many strange and exciting wonders. Astronomers already know of some of the bizarre objects that exist at our Galactic center, including like vast cosmic dust clouds, bright star clusters, swirling rings of gas, and even a supermassive black hole. Much of the Galactic Center is shielded from our view in visible light by the intervening dust and gas, but it can be explored using other forms of electromagnetic radiation. The featured video is actually a digital zoom into the Milky Way's center which starts by utilizing visible light images from the Digitized Sky Survey. As the movie proceeds, the light shown shifts to dust-penetrating infrared and highlights gas clouds that were recently discovered in 2013 to be falling toward central black hole. In 2018 May, observations of a star passing near the Milky Way's central black hole showed, for the first time, a gravitational redshift of the star's light -- as expected from Einstein's general relativity.