SciByte

To see one this size is very rare

Mars Reconnaissance Orbiter took the lucky photograph using a high-resolution camera called HiRISE

March 14, the camera spotted the dust devil leaving a trail across land in Mars’ northern hemisphere, where spring brings temperatures of up to -25° Celsius in some places

a new study also points to a more earthbound culprit: the presence of a land bridge connecting Asia to North America.

debated whether the climate swings were driven by sharp variations in solar activity or simply by unstable climatic processes

Earth's climate has been relatively stable since the end of the last ice age

temperatures were fairly stable, too, after the ice age began in earnest about 100,000 years ago

20,000 years later, things became unhinged

global sea level dropped to about 50 meters lower than it is today

As the ice sheets that covered North America and northern Eurasia snatched up more and more of Earth's water

exposed a broad strip of land that connected what is today Alaska and Siberia

Ancient animals used the land bridge, which measured as much as 1500 kilometers wide in spots, to roam back and forth between Asia and North America

also huge consequences for Earth's climate

two sets of climate simulations

one in which the Bering Strait was open

one in which it was blocked

each set of simulations, the researchers gradually added large amounts of fresh water to the North Atlantic between the latitudes of 20° and 50

researchers propose, this swath, which spans the latitudes from southern Cuba to southern England, would have received large amounts of meltwater from Northern Hemisphere ice sheets during warm spells that occasionally punctuated the ice age

Today, the surface waters in this swath affect the temperature and salinity of water even farther north in the Atlantic

a region where surface waters cool, sink to the seafloor, and then flow southward—a critical link of the worldwide conveyor belt of ocean circulatio

Gulf Stream, which brings climate-warming waters from the equator to the North Atlantic, comes to a halt.

If waters of the far North Atlantic don't sink, says Hu, much of the large-scale ocean circulation worldwide temporarily collapses

surface waters became so fresh that they never got denser than the underlying salty water, and therefore never sank

shutting down ocean circulation and plunging areas around the North Atlantic, including Greenland, into a cold spell

researchers noted a critical difference between the sets of simulations: When the Bering Strait was closed, it took as many as 1400 years for ocean circulation to recover; when the strait was open, the circulation rarely took more than 400 years to recuperate

sign that ocean circulation is stable when the strait is open

Whenever the ocean circulation shut down in the simulations, temperatures in Greenland suddenly dropped by 12°C—a decrease similar in magnitude to many abrupt cold snaps chronicled in the Greenland ice core records

belongs to one of the most mysterious groups of dinosaurs, the Alvarezsauridae, and it is one of the largest members, 2.6 m, of the family

The two eggs found together with the bones during the expedition might have been inside the oviducts of the Bonapartenykus female when the animal perished

numerous eggshell fragments later found show considerable calcite resorption of the inner eggshell layer

suggest that at least some of the eggs were incubated and contained embryos at an advanced stage of their development.

analyzed the eggshells and found that it did not belong to any known category of the eggshell microstructure-based taxonomy

a new egg-family, the Arraigadoolithidae

using the electron scanning microscopy I observed unusual fossilized objects inside of the pneumatic canal of the eggshells

the first evidence of fungal contamination of dinosaur eggs

if it stopped, air temperatures could change quickly.

computer simulation actually showed the same temperature fluctuations over Greenland as researchers have found, via core ice samples, occurred the last time the Strait closed during the last Ice Age.

When the researchers added plastin 3 back to motor neurons in zebrafish that were genetically altered so they couldn’t produce SMN, the zebrafish regained most of their swimming abilities movement that had been severely limited by their reduced SMN. These findings tied the presence of plastin 3 – alone, without SMN – to the recovery of lost movement

without SMN in their cells still eventually died, so the addition of plastin 3 alone is not a therapeutic option

using animal studies to pinpoint the role of plastin 3 in this disease

In zebrafish genetically altered so they don’t produce SMN, plastin 3 levels remained low, as well.

lowering plastin 3 first in the fish – SMN was unaffected. This showed that the plastin 3 decrease occurred only when SMN was lowered first

SMN production was stimulated in zebrafish initially lacking the protein, plastin 3 levels were restored as well

researchers determined that decreased SMN influences plastin 3 production at a late point in the process called translation, when amino acids are strung together to form the protein’s initial shape

lack of SMN creates conditions in which too little plastin 3 is made to complete the protein’s normal functions – in these animals, the reduction was about four-fold

maybe SMN is affecting translation of other proteins that could be contributing to spinal muscular atrophy

That hasn’t been shown before

examination of zebrafish motor neurons suggested that decreased plastin 3 affects these cells in at least two ways

damaging axons, branch-like extensions that allow for communication among nerve cells

destabilizing synapses, structures through which those signals pass

result of the added plastin 3, the fish recovered their ability to turn and swim, movements they were previously unable to make.

rescued axons, synaptic proteins and behavior all by putting plastin 3 back in motor neurons,” she said. “That’s very encouraging.”

negative test reduces the likelihood

a positive test does not necessarily confirm

concerns: that it could be overused in general

and there will be

both false positives and false negatives

medical community is going to have to develop its own standards

Find Orion, Leo or Crux by going outside more than an hour after sunset (about 8-10pm local time).

Match your nighttime sky to one of the provided magnitude charts.

Report your observation.

Compare your observation to thousands around the world

You can also use the new web application data submission process

People in 115 countries have contributed over 75,000 measurements during the past six years

Another exciting step against Alzheimer’s

also came across seven new colonies (one shown at left), bringing the total to 44

Scientists have found twice as many emperor penguins (Aptenodytes forsteri) as previously thought to exist, roughly 595,000 (plus or minus 81,000

a new approach is to use satellite images, and today researchers report the results of the first such comprehensive stu

Previously, scientists had observed the planet's auroras only once, during a Voyager flyby in 1986

instruments had a much better view of the glows

lasted longer, covered a larger area, and festooned the unlit side of Uranus

other factors were different

planet's rotational axis was pointed almost directly at the sun

in 2011 the axis lay almost perpendicular to the flow of solar wind

new observations should help scientists better understand Uranus's odd magnetic field, whose axis is both offset from the center of the planet and tilts at an angle of 60° from the rotational axis.