Extreme heat can pose several health risks, such as dehydration, hyperthermia and even death, especially during sustained periods of high temperatures. However, a uniform definition of a heat wave doesn’t exist. As a result, public health agencies may be unsure of when to activate heat alerts, cooling centers and other protective measures. A University of Missouri School of Medicine researcher has developed a uniform definition of a heat wave that may help public health agencies prepare for extreme temperatures.

As renewable energy sources goes, solar rays have historically hogged the limelight. 

But two Virginia Tech researchers have stolen the spotlight from the sun by discovering a way to maximize the amount of electricity that can be generated from the wastewater we flush down the toilet. 

Asteroids headed for a collision with the Earth, if found early enough, can be acted upon to prevent the potentially devastating consequences of an impact. One technique to divert an asteroid, called kinetic impact, uses a spacecraft to crash into the body at high speeds.

This approach delivers the momentum of the spacecraft, while also providing an additional boost of momentum through the production of impact crater ejecta exceeding the asteroid’s escape velocity. Researchers at Lawrence Livermore National Laboratory (LLNL) have been studying the effectiveness of the kinetic-impactor strategy by carrying out 3D simulations of the process.

In a new paper published in Icarus(link is external), LLNL planetary defense researchers find that asteroid deflection by kinetic impact is sensitive to a range of asteroid characteristics, including strength, porosity, rotation and shape. These and other asteroid properties may not be well constrained before an actual deflection mission is staged, leading to variability in the deflection outcome. By simulating a range of initial conditions for the target asteroids, researchers were able to quantify, for example, how greater target strength decreases the delivered momentum impulse and how, for an asteroid of constant size, added porosity can result in more effective deflections, despite the dampening of the shock waves produced during an impact

Scientists have found a new way to tease out signals about Earth's climatic past from soil deposits on gravel and pebbles, adding an unprecedented level of detail to the existing paleoclimate record and revealing a time in North America's past when summers were wetter than normal.

A research team led by soil scientists at the University of California, Berkeley obtained data about precipitation and temperature in North America spanning the past 120,000 years, which covers glacial and interglacial periods during the Pleistocene Epoch. They did this at thousand-year resolutions -- a blink of an eye in geologic terms -- through a microanalysis of the carbonate deposits that formed growth rings around rocks, some measuring just 3 millimeters thick.

New measurements from a NASA satellite have allowed researchers to identify and quantify, for the first time, how climate-driven increases of liquid water storage on land have affected the rate of sea level rise.

A new study by scientists at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, and the University of California, Irvine, shows that while ice sheets and glaciers continue to melt, changes in weather and climate over the past decade have caused Earth's continents to soak up and store an extra 3.2 trillion tons of water in soils, lakes and underground aquifers, temporarily slowing the rate of sea level rise by about 20 percent.

The water gains over land were spread globally, but taken together they equal the volume of Lake Huron, the world's seventh largest lake. The study is published in the Feb. 12 issue of the journal Science.

When carbon dioxide is stored underground in a process known as geological sequestration, it can find multiple escape pathways due to chemical reactions between carbon dioxide, water, rocks and cement from abandoned wells, according to Penn State researchers.

The Greenland and Antarctic ice sheets will make a dominant contribution to 21st century sea-level rise if current climate trends continue. However, predicting the expected loss of ice sheet mass is difficult due to the complexity of modeling ice sheet behavior.

To better understand this loss, a team of Sandia National Laboratories researchers has been improving the reliability and efficiency of computational models that describe ice sheet behavior and dynamics. The team includes researchers Irina Demeshko, Mike Eldred, John Jakeman, Mauro Perego, Andy Salinger, Irina Tezaur and Ray Tuminaro.

This weekend bird enthusiasts from around the world will become citizen scientists for a few days during the 19th annual Great Backyard Bird Count, which is happening this year February 12-15.

During this four-day event, which is organized by the Cornell Lab of Ornithology, the National Audubon Society and Bird Studies Canada, people will be headed outdoors to count their local birds in the name of science.

The largest ever study of howling in the 'canid' family of species -- which includes wolves, jackals and domestic dogs -- has shown that the various species and subspecies have distinguishing repertoires of howling, or "vocal fingerprints": different types of howls are used with varying regularity depending on the canid species. 

Researchers used computer algorithms for the first time to analyse howling, distilling over 2,000 different howls into 21 howl types based on pitch and fluctuation, and then matching up patterns of howling. 

They found that the frequency with which types of howls are used -- from flat to highly modulated -- corresponded to the species of canid, whether dog or coyote, as well as to the subspecies of wolf. 

University of Alaska Fairbanks mathematicians and glaciologists have taken a first step toward understanding how glacier ice flowing off Greenland affects sea levels.

Andy Aschwanden, Martin Truffer and Mark Fahnestock used mathematical computer models and field tests to reproduce the flow of 29 inlet glaciers fed by the Greenland ice sheet. They compared their data with data from NASA's Operation IceBridge North aerial campaign.

The comparisons showed that the computer models accurately depicted current flow conditions in topographically complex Greenland.