Muito ☺️ Fofo!! Lindo Trabalho.

Maurice Utrillo’s Paris Street, 1914 (via here)

Silk leaf

http://www.dezeen.com/2014/07/25/movie-silk-leaf-first-man-made-synthetic-biological-leaf-space-travel/

Interessante!!

Sensation of Taste Is Built into Brain

Roast turkey. Stuffing. Mashed potatoes and gravy. Pie. Thanksgiving conjures up all sorts of flavors. If you close your eyes you can almost taste them. In fact, one day you may be able to—without food.

Scientists from Columbia University have figured out how to turn tastes on and off in the brain using optogenetics—a technique that uses penetrating light and genetic manipulation to turn brain cells on and off. They reported their findings in an article published in Nature. By manipulating brain cells in mice this way, the scientists were able to evoke different tastes without the food chemicals actually being present on the mice’s tongues.

The experiments “truly reconceptualize what we consider the sensory experience,” said Charles Zuker, head of the Zuker lab at Columbia and co-author on the paper. The results further demonstrate “that the sense of taste is hardwired in our brains,” Zuker said, unlike our sense of smell, which is strongly linked to taste but almost entirely dependent on experience.

Typically when we eat, the raised bumps, or papillae, that cover our tongues, pick up chemicals in foods and transmit tastes to the brain. There are five main types of papillae corresponding to each of the five basic tastes—sweet, sour, salty, bitter and umami. Contrary to popular belief, these aren’t clustered in particular places on the tongue, with bitter in the back and sweet at the front, but are spaced about evenly on the tongue.

A taste map may in fact exist, but it appears to be in the brain rather than on the tongue. First the researchers singled out the mice’s sweet and bitter taste centers in the brain, which are separated by approximately two millimeters in the insula. They concentrated on only sweet and bitter because the two are the most distinct from each other and also the most salient for humans, mice and other animals due their evolutionary importance to survival. Sweet usually indicates the presence of nutrients, whereas bitter signals potential danger of poison.

Zuker and his team then optogenetically stimulated the areas with light and in a series of behavioral tests, were able to have the mice taste sweet or bitter with only plain water. When the researchers activated the sweet neurons, they observed behavior consistent what with happens when mice normally encounter sweet foods: their licking increased significantly, even when the animals’ thirst was satiated. When the scientists stimulated neurons associated with bitter flavors, the mice stopped licking, seemed to scrub at their tongues and even gagged, depending on the level of optogenetic stimulation.

The researchers then performed the tests on animals that had never tasted sweet or bitter in their lives and found the same results. In the last set of experiments the researchers applied to the tongue of the mice chemicals that tasted sweet and bitter and compared their reactions to what happened when they simply stimulated the corresponding neurons optogenetically. There was no difference in the way the animals responded, “proving taste is hardwired in the brain,” Zuker said.

This doesn’t mean that there is no such thing as an “acquired taste,” Zuker clarified. For example, hákarl, fermented shark meat and national dish of Iceland, once called “the single worst, most disgusting and terrible tasting thing,” by famously acerbic food critic Anthony Bourdain is relished by many on the Nordic island nation. Humans are more complicated than mice. Taste can also be shaped by experience and culture. But the basics of this sensation are present from the beginning.

“Every baby smiles to sweet and frowns for bitter,” Zuker explained. “Taste mostly retains that hardwired response unless there is something that supersedes it. There are some things we consume [that] are innately aversive. But we take the gain with the bad if they have a positively reinforcing result.” Coffee or alcohol, for instance, are distinctly bitter, but many people learn to enjoy them over time due to the feelings of stimulation and inebriation they bring, respectively.

Gary Beauchamp, president of the Monell Chemical Senses Center in Pennsylvania, calls the research “a very clear and elegant approach,” confirming the long-standing hypothesis that taste is indeed evolutionarily hardwired. But Beauchamp also notes that sweet and bitter compounds can influence each other in the mouth to affect taste before they reach the brain. “In the real world, where foods are mixtures of things, it’s much more complex than what this study would suggest. Nevertheless, this is excellent work showing that these pathways are innately organized,” he said.  

Zuker is aware that sweet and bitter are at the extremes of the taste spectrum and may not be representative of all tastes. But he expects similar results testing other tastes, which are also evolutionarily based. Salt, for example, signals electrolytes. “The next question is how activity in these cortical fields integrates with rest of brain,” to form experience and lasting taste memories – such as those we make at Thanksgiving.

Source: Scientific American

Whale automata by Sylvain Gautier.

Suzuki Harunobu (1725-1770)  鈴木春信

Reading a Letter

Lentes gravitacionais.

What is Gravitational Lensing?

A gravitational lens is a distribution of matter (such as a cluster of galaxies) between a distant light source and an observer, that is capable of bending the light from the source as the light travels towards the observer. This effect is known as gravitational lensing, and the amount of bending is one of the predictions of Albert Einstein’s general theory of relativity.

This illustration shows how gravitational lensing works. The gravity of a large galaxy cluster is so strong, it bends, brightens and distorts the light of distant galaxies behind it. The scale has been greatly exaggerated; in reality, the distant galaxy is much further away and much smaller. Credit: NASA, ESA, L. Calcada

There are three classes of gravitational lensing:

1° Strong lensing: where there are easily visible distortions such as the formation of Einstein rings, arcs, and multiple images.

Einstein ring. credit: NASA/ESA&Hubble

2° Weak lensing: where the distortions of background sources are much smaller and can only be detected by analyzing large numbers of sources in a statistical way to find coherent distortions of only a few percent. The lensing shows up statistically as a preferred stretching of the background objects perpendicular to the direction to the centre of the lens. By measuring the shapes and orientations of large numbers of distant galaxies, their orientations can be averaged to measure the shear of the lensing field in any region. This, in turn, can be used to reconstruct the mass distribution in the area: in particular, the background distribution of dark matter can be reconstructed. Since galaxies are intrinsically elliptical and the weak gravitational lensing signal is small, a very large number of galaxies must be used in these surveys.

The effects of foreground galaxy cluster mass on background galaxy shapes. The upper left panel shows (projected onto the plane of the sky) the shapes of cluster members (in yellow) and background galaxies (in white), ignoring the effects of weak lensing. The lower right panel shows this same scenario, but includes the effects of lensing. The middle panel shows a 3-d representation of the positions of cluster and source galaxies, relative to the observer. Note that the background galaxies appear stretched tangentially around the cluster.

3° Microlensing: where no distortion in shape can be seen but the amount of light received from a background object changes in time. The lensing object may be stars in the Milky Way in one typical case, with the background source being stars in a remote galaxy, or, in another case, an even more distant quasar. The effect is small, such that (in the case of strong lensing) even a galaxy with a mass more than 100 billion times that of the Sun will produce multiple images separated by only a few arcseconds. Galaxy clusters can produce separations of several arcminutes. In both cases the galaxies and sources are quite distant, many hundreds of megaparsecs away from our Galaxy.

Gravitational lenses act equally on all kinds of electromagnetic radiation, not just visible light. Weak lensing effects are being studied for the cosmic microwave background as well as galaxy surveys. Strong lenses have been observed in radio and x-ray regimes as well. If a strong lens produces multiple images, there will be a relative time delay between two paths: that is, in one image the lensed object will be observed before the other image.

As an exoplanet passes in front of a more distant star, its gravity causes the trajectory of the starlight to bend, and in some cases results in a brief brightening of the background star as seen by a telescope. The artistic concept illustrates this effect. This phenomenon of gravitational microlensing enables scientists to search for exoplanets that are too distant and dark to detect any other way.Credits: NASA Ames/JPL-Caltech/T. Pyle

Explanation in terms of space–time curvature

Simulated gravitational lensing by black hole by: Earther

In general relativity, light follows the curvature of spacetime, hence when light passes around a massive object, it is bent. This means that the light from an object on the other side will be bent towards an observer’s eye, just like an ordinary lens. In General Relativity the speed of light depends on the gravitational potential (aka the metric) and this bending can be viewed as a consequence of the light traveling along a gradient in light speed. Light rays are the boundary between the future, the spacelike, and the past regions. The gravitational attraction can be viewed as the motion of undisturbed objects in a background curved geometry or alternatively as the response of objects to a force in a flat geometry.

A galaxy perfectly aligned with a supernova (supernova PS1-10afx) acts as a cosmic magnifying glass, making it appear 100 billion times more dazzling than our Sun. Image credit: Anupreeta More/Kavli IPMU.

To learn more, click here. 

Tassel

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Eight Small Satellites Will Give Us a New Look Inside Hurricanes

The same GPS technology that helps people get where they’re going in a car will soon be used in space in an effort to improve hurricane forecasting. The technology is a key capability in a NASA mission called the Cyclone Global Navigation Satellite System (CYGNSS).

The CYGNSS mission, led by the University of Michigan, will use eight micro-satellite observatories to measure wind speeds over Earth’s oceans, increasing the ability of scientists to understand and predict hurricanes. Each microsatellite observatory will make observations based on the signals from four GPS satellites.

The CYGNSS microsatellite observatories will only receive signals broadcast directly to them from GPS satellites already orbiting the Earth and the reflection of the same satellite’s signal reflected from the Earth’s surface. The CYGNSS satellites themselves will not broadcast.

The use of eight microsatellite observatories will decrease the revisit time as compared with current individual weather satellites. The spacecraft will be deployed separately around the planet, with successive satellites passing over the same region every 12 minutes.

This will be the first time that satellites can peer through heavy tropical rainfall into the middle of hurricanes and predict how intense they are before and during landfall.

As the CYGNSS and GPS constellations orbit around the Earth, the interaction of the two systems will result in a new image of wind speed over the entire tropics every few hours, compared to every few days for a single satellite.

Another advantage of CYGNSS is that its orbit is designed to measure only in the tropics…where hurricanes develop and are most often located. The focus on tropical activity means that the instruments will be able to gather much more useful data on weather systems exclusively found in the tropics. This data will ultimately be used to help forecasters and emergency managers make lifesaving decisions.

Watch Launch!

Launch of CYGNSS is scheduled for 8:24 a.m. EST on Monday, Dec. 12 from our Kennedy Space Center in Florida. CYGNSS will launch aboard an Orbital ATK Pegasus XL rocket, which will be deployed from Orbital’s “Stargazer” L-1011 carrier aircraft. 

Pegasus is a winged, three-stage solid propellant rocket that can launch a satellite into low Earth orbit. How does it work? Great question! 

After takeoff, the aircraft (which looks like a commercial airplane..but with some special quirks) flies to about 39,000 feet over the ocean and releases the rocket. 

After a five-second free fall in a horizontal position, the Pegasus first stage ignites. The aerodynamic lift, generated by the rocket’s triangle-shaped wing, delivers the payload into orbit in about 10 minutes. 

Pegasus is used to deploy small satellites weighing up to 1,000 pounds into low Earth orbit. 

Watch live coverage HERE. 

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com

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via :))) by Inna Dubrovskaya / 500px Autumn Leaves