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suggest that some stimulants may actually have an opposite effect for people who naturally favour the difficult tasks of life that come with greater rewards

found that rats – like humans – show varying levels of willingness to expend high or low degrees of mental effort to obtain food rewards.

with stimulants, the “slacker” rats that typically avoided challenges worked significantly harder when given amphetamines

worker” rats that typically embraced challenges were less motivated by caffeine or amphetamine

For slacker rats, amphetamine sharpened the mental work ethic, making the animals more likely to choose the harder task.

can’t yet explain why stimulants would cause workers to choose the easier task

One possibility is that hard workers are already performing optimally, so anything that swings the system out of whack, such as stimulants, could cause a net decrease in productivity.

shed light on the potential risks the comet deaths on the sun could pose for us on Earth

In recent decades, astronomers have witnessed even dramatic interactions between comets and the sun

researchers are analyzing how these so-called sun-diving comets lose their mass and energy depending on how close they get to the star.

Such data can show us for the first time what is inside a comet

All other data to date, apart from Jupiter impacts like Shoemaker-Levy 9, are only from the surface layers."

the sun's lower atmosphere. This lies about 4,350 miles (7,000 kilometers) above the top of the photosphere, the sun's brightest visible layer.

sunskimmer" comets — ones that dive toward the sun but not into its lower atmosphere — can slowly get vaporized by sunlight in deaths that last hundreds to thousands of seconds, depending on their mass

scientists calculated that the comets should emit weak but detectable extreme ultraviolet radiation.

sunplunger" comets that get even closer to the sun will meet their demise in only a few seconds, as they collide with the dense layers of the sun's lower atmosphere

most massive comets smashed into the sun, they would produce dramatic explosions just above the photosphere

To create their model, the scientists looked at the first direct observations of sunskimmer comets, captured last year by NASA's sun-watching Solar Dynamics Observatory (SDO).

comet, C/2011 N3, was completely destroyed after passing about 62,000 miles (100,000 km) above the photosphere

comet, Lovejoy (C/2011 W3), survived a close approach to a similar distance of 87,000 miles (140,000 km), although it lost a significant fraction of its mass in the process

Both events were in line with the predictions of the researchers' new model.

corona is hot, but its density is so small that the heat Lovejoy experienced "would be quite safe even on our skin

Comet Lovejoy did pass through the sun's million-degree corona

Comets might help serve as probes of the sun's atmosphere and magnetic field, helping to uncover its secrets

cometary flares that the very largest comets might release if they slammed into the sun can be 100 times more energetic than the largest solar flares ever observed

Such comets are, however, very, very rare today, though they may have been commoner in the early system

In the west, Jupiter hangs low on the horizon. Around mid-month, the planet disappears into the sunset

Venus blazes just above Jupiter in the west. Use a telescope to see its crescent phase.

In the south, Mars is already climbing high. It will remain visible into the early morning

Saturn will shine low in the east in the evening but climb higher during the night. On April 15th, Saturn reaches opposition, meaning it is opposite the Sun in Earth’s sky. It is also closer to Earth than it’ll be the rest of the year, making it appear slightly bigger and brighter

Constellations and Deep-Sky Objects

Additionally, missions such as Hubble, Fermi and Swift will receive continued funding

only mission that took a hit was the Spitzer infrared telescope, which – as of now — will be closed out in 2015, which is sooner than requested.

Senior Review of missions takes place every two years

In the Review, missions are ranked as which are most successful

previous Senior Reviews led to the removal of funding for the weakest 10-20% of extended missions

Hubble Space Telescope will continue at the currently funded levels

Chandra will also continue at current levels, but its Guest Observer budget will actually be increased to account for decreases in Fiscal Year 2011

Fermi operations are extended through FY16, with a 10 percent per year reduction starting in FY14.

Swift and Kepler mission operations are extended through FY16, including funding for data analysis.

Planck will support one year extended operations of the Low Frequency Instrument (LFI).

Spitzer’s operations are extended through FY14 with closeout in FY15

U.S. science support of Suzaku is extended to March 2015.

Funding for U.S. support of XMM-Newton is extended through March 2015.

all FY15-FY16 decisions are for planning purposes and they will be revisited in the 2014 Senior Review

send me the right stars for that exact time and I'll put it in the movie

Tyson did just that and the correct star field has been included in the re-release.

the drive took place on a carefully programmed route in San Jose and showed one of the possibilities that self-driving cars could offer.

we've now safely completed more than 200,000 miles of computer-led driving, gathering great experiences and an overwhelming number of enthusiastic supporters

innovative app for iPads and iPhones

available for free

brought together faculty and students in astrophysics, art, and technology for a summer institute last year

team quickly settled on the idea to create an app, and also developed it into an exhibit that provides additional information and shows the app's output on a large screen

scheduled for long-term installation in the Lick Observatory visitors gallery later this month

Kepler Explorer starts with drop-down menus listing all the Kepler-discovered planetary systems, plus our own solar system

selected system is displayed in a view that shows the planet or planets in their orbits around the host star

Shown in real time the planets look motionless, but moving a slider increases the speed until the planets zip around their star

lets users zoom in and move around the system, and tapping on an individual planet brings it up for further exploration. Another view shows the relative sizes of the individual planets compared to their host star

when viewing individual planets

The user can manipulate the composition of the planet and its atmosphere and see which mixtures of components (iron, rock, water, and hydrogen) are consistent with Kepler's observations

represents graphically the type of in-depth analysis that Fortney does for the Kepler Mission

the app allows anyone to explore the properties of many different planets very quickly

only measures the radius of a planet, or how big it is. In most cases, the mass of the planet is unknown

there may be different combinations of components that result in a planet of a given size

's interactive graphics show how this works

sliders for different components and how they are partitioned in the core and the atmosphere, and as you move the sliders the image of the planet grows and shrinks, based on hundreds of calculations

the app tells you when the size of your planet matches the observations

calculations involved took hours of computer time, but the results are stored in tables so the app can use them on the fly.

part of a BBC/Discovery Channel-funded expedition and is believed to be at least 10,000 years old, if not older

If further study confirms the preliminary findings, it would be the first mammoth carcass revealing signs of human interaction in the region.

in such good shape that much of its flesh is still intact, retaining its pink color. The blonde-red hue of Yuka's woolly coat also remains.

first relatively complete mammoth carcass -- that is, a body with soft tissues preserved -- to show evidence of human association

carbon dating is still in the works, the researchers believe Yuka died at least 10,000 years ago, but may be much older

The animal was about 2 ½ years old when it died.

appears that Yuka was pursued by one or more lions or another large field, judging from deep, unhealed scratches in the hide and bite marks on the tail

Yuka then apparently fell, breaking one of the lower hind legs

humans may have moved in to control the carcass, butchering much of the animal and removing parts that they would use immediately.

may, in fact, have reburied the rest of the carcass to keep it in reserve for possible later use

removed parts include most of the main core mass of Yuka's body, including organs, vertebrae, ribs, associated musculature, and some of the meat from upper parts of the legs

Kevin Campbell of the University of Manitoba also studied Yuka

Campbell famously published the genetic code of mammoth hemoglobin a few years ago

Most permafrost-preserved mammoth specimens consist solely of bones or bone fragments that currently provide little new insight into the species' biology in life

This extremely rare finding of a near complete specimen, like the discovery of the baby mammoth Lyuba in 2007, will be a boon to researchers as it will help them link observed phenotypes (morphological features that we can see) with genotype (DNA sequences)."

Such information could help reveal whether or not mammoths had all of the same hair colors that humans do

An intriguing and controversial application would be to bring a mammoth back to life via cloning.

producer and director of a forthcoming BBC/Discovery Channel show called "Woolly Mammoth"

told Discovery News that cloning a mammoth could take years or even decades.

found in the Yixian Formation, a fossil deposit in northeastern China that over the last two decades has yielded dozens of dinosaur skeletons so finely preserved that it’s possible to discern feather-like structures.

early feathered members of the tyrannosaur family have been found, they were very smal

If the primary purpose of feathers was insulation, a possibility suggested by the feathers’ down-like shape, then larger tyrannosaurs might not have needed them. Thanks to small surface-to-volume body ratios, large-bodied animals tend to maintain heat easily.

didn’t know whether these larger-bodied forms would show as many.”

significance of Y. huali is its body size and the apparent density of feather-like structures

Yutyrannus skull. Image: Zang Hailong

What were tyrannosaur feathers used for? Might the king of dinosaurs have strutted like a peacock?

At this point we don’t have any data on the coloration of the plumage

finding 61 confirmed alien planets to date

members have estimated that the vast majority of these candidates — 80 percent or more — will likely end up being the real deal.

artist's conception illustrates Kepler-22b, a planet known to comfortably circle in the habitable zone of a sun-like star. CREDIT: NASA/Ames/JPL-Caltech

Seeing more transits will also increase the signal-to-noise ratio for closer-in planets, allowing more of them to be detected, researchers have said

Scientists have long debated whether gigantic dinosaurs lost their feathers the bigger they got or were just not as extensively covered.

this is the first direct sign of a huge, shaggy dinosaur

name is a blend of Latin and Mandarin, which translates to "beautiful feathered tyrant."

recovered from a quarry in China's Liaoning province by a private fossil dealer

Most striking were the remains of down-like feathers on the neck and arm

coverage was patchy, scientists suspected the species had feathers over much of its body

would have felt like touching "long, thick fur

compared it to the feathers of an emu.

Y. huali would have reached T. rex's chest.

dino-fuzz likely provided insulation, though camouflage or showing it off like a peacock could not be ruled out.

Since T. rex is related to this newfound feathery species, chances are good that T. rex was feathered as well

Based on the shapes of the jaw and skull bones found in the fossils, the team concluded that the three animals belonged to the same species and were tyrannosaurs

broader classification of two-legged meat-eaters called theropods

biggest of the newly described creatures — the largest extensively feathered dino known to date — was about one-quarter the weight of its relative, Tyrannosaurus rex

smaller dinosaur is named Yutyrannus hauli, which translates to “beautiful feathered tyrant

new species had feathers that were at least 15 centimeters long and look as if they covered the dinosaur’s skin

might have given the dinosaur a shaggy appearance

the full extent of this covering is difficult to confirm because the specimens aren’t complete.

For the vast majority of dinosaurs we only have bone. We don’t have feathers or featherless skin

Full-feathered dinosaurs that have been discovered so far have been much smaller

much more likely to lose body heat because of their size

scientists thought these petite creatures used a fluffy layer to stay warm

study authors think that the newfound dinos might have also needed some insulation

But Norell is not convinced

Many large animals that live in warm climates, such as modern giraffes and wildebeests, have external covering but don’t need it for insulation, he says.

feathers might also have helped the dinosaurs show off and attract mates.

Other traits the new dinos had include a high, bumpy nose plate, known as a midline crest

unclear what type of posture the animals maintained, Sullivan estimates that the full-grown dino stood about 2.5 meters tall.

analysis suggests that Y. huali differed from tyrannosaurids in its growth strategy13

first noted by astronomers in 2010

it was thought the solar system consisted of just five planets

speculation that it might have as many as seven

other work has shown that there are likely six planets, five of which are believed to have a mass close to that of Neptune

other appears closer in mass to Saturn

to these conclusions by studying the way a star appears to wobble (a Doppler shift

studying these light shifts, astronomers can deduce not only the size of the planet that causes it, but its period as well

didn’t make any new observations

he went back and looked at the original data using different kinds of statistical analysis techniques

found evidence for three more planets, all much smaller than the original six

estimates to be 1.3, 1.9, and 5.1 times the size of Earth

much shorter periods (1.2, 10 and 68 days) than

they are very close to their star, closer even than Mercury is to our sun

far too hot to support water retention or life, at least as we know it.

doesn’t actually prove that any of the planets suspected of revolving around HD 10180 actually exist

merely offers strong evidence

statistical evidence offered by Tuomi suggesting that if there are truly planets there, they all appear to have stable orbits.