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Field of study and family structure explain PhD wage gap

23 May 2016

Nature: Much of the pay gap between men and women with PhDs comes about because women tend to pursue degrees in less lucrative fields, a new analysis has found. But even after controlling for field of study, women still earned an average of 11% less than men in their first year. That difference emerged because married women with children earned significantly less than their counterparts. Unmarried, childless women earned the same annual salary as men with a PhD in the same field. The analysis, by Bruce Weinberg of the Ohio State University in Columbus and his colleagues, examined about 1200 graduates of PhD programs in the US. The analysis did not identify any specific factors explaining why married women with children earn less than their colleagues.

Briefing provides clues to Trump's stance on energy policy

23 May 2016

New York Times: Donald Trump's comments about climate change and energy policy, until now mostly restricted to Twitter, suggest he does not accept global warming. A briefing prepared by Representative Kevin Cramer (R-ND) for Trump has provided a bit more insight on Trump's potential plans for energy policy. In the briefing, Cramer suggests that Trump could eliminate a federal rule to protect waterways and wetlands, an EPA regulation setting methane emissions standards, and the Clean Power Plan. Describing the briefing in an interview, Cramer said that any energy policy would incorporate all forms of energy, without punishing coal, oil, and natural gas production. Further details are expected in a speech by Trump at an oil conference on Thursday. Both Republicans and environmental groups are concerned over Trump's unclear position.

NIST has restored its million-pound deadweight machine

23 May 2016

NPR: In 1965 NIST in Gaithersburg, Maryland, built a machine that uses a stack of stainless steel plates to apply up to 1 million pounds (4.4 million N) of force to test materials' physical properties. It was then, and still is, the largest machine of its kind in the world. Over the past year-and-a-half, the machine underwent refurbishment for the first time. The weights, which accumulated damage over the years, were repaired, and the entire machine was taken apart and then put back together and recalibrated. Earlier this month the machine returned to operation and is working through a backlog of measurement requests.

Tracking Greenland’s melting ice with seismic waves

23 May 2016
The seasonal loading and unloading of ice atop the island alters the speed at which seismic waves propagate through it.

Brittle asteroids may result in reduced impact threat

23 May 2016

New Scientist: Asteroids and comets more than 1 km across could devastate Earth if they were to hit the planet. However, Desireé Cotto-Figueroa of Arizona State University in Tempe and her colleagues say that we may not have as much to worry about from asteroids as we thought. Cotto-Figueroa's team tested centimeter-sized cubes from meteorites recovered on the ground. By crushing the samples, the researchers found that the asteroids were nearly as brittle as concrete, which means they are much weaker than most Earth rocks. The researchers extrapolated their measurements of the samples up to much larger scales to calculate the break-up rate for different sizes and types of meteorites. The calculations suggest that rocky asteroids are much more likely to break apart in Earth's atmosphere and turn into a spray of fireballs instead of remaining whole and creating large impacts.

Curved shape of Hawaiian island chain may be due to hot-spot plumes in the deep mantle

20 May 2016
Ars Technica: A kink in the Hawaiian seamount chain has prompted researchers to look more closely at plate tectonics and associated mantle plumes of hot rock. Rakib Hassan and Dietmar Müller of the University of Sydney and their coworkers have used computer modeling to study that sharp bend, once thought to be caused by a change in direction of the tectonic plate. The researchers focused on the underlying plumes to simulate what happens deep in Earth’s mantle. At that depth, the rock is unusually dense and hot and becomes putty-like. As the oceanic crust sinks, that dense bottom layer of the mantle appears to get squeezed like toothpaste from a tube and bulges up beneath the Pacific Plate as a series of hot-spot plumes. Moreover, the plumes can migrate. Based on paleomagnetic and radiometric age data, the Hawaiian plume experienced a rapid southward motion between 100 million and 50 million years ago. Because the top of the plume can move at a different pace than the bottom, the plume can tilt and straighten over time, like smoke from a chimney. Not only does that movement correlate well with the sharp bend in the Hawaiian chain, it also explains the more subtle bend in another seamount structure, the Louisville chain, located in the South Pacific.

Swallowable robots can extract foreign objects

20 May 2016

Economist: Each year in the US alone, more than 3500 people—primarily children—swallow button-cell batteries, which can burn holes in the stomach. Removing the batteries generally requires surgery. Now Daniela Rus and Shuhei Miyashita of MIT have developed a magnet-containing robot that can be placed inside a capsule and swallowed. Once the capsule dissolves, the robot unfolds itself and can be moved via magnetic fields from outside the body. After the robot latches onto the battery, the robot tows its haul to the intestine, from which the battery and robot are later excreted. A second robot can then be swallowed and moved to the location where the battery was found to deliver medication that speeds healing of any burns incurred. The team, which tested the robots in a transparent artificial stomach system, now plans to try them out on live pigs, a procedure that will require additional imaging systems to locate the battery and maneuver the robots.

New US wage law may result in pay increase for postdocs

20 May 2016

Nature: In the US, the average yearly salary for a postdoc is about $45 000, and many postdocs work much more than 40 hours per week. A new rule finalized by the US Department of Labor, which takes effect on 1 December, will make overtime pay mandatory for many postdoctoral researchers who make less than $47 476 per year. In the US, overtime pay is 1.5 times the normal hourly wage; that rate is triggered when a worker exceeds 40 hours at a single job in a week. Many institutions and funders of postdoc positions will likely opt to increase salaries above the minimum level. However, other positions may get eliminated to compensate. The overtime rule does not apply to postdoctoral positions for which the primary duty is teaching, which means that many humanities postdocs will not benefit.

Moo-Young Han

20 May 2016

Tiny robot floats like a butterfly, lands like a bee

20 May 2016
Guardian: Weighing a tenth of a gram and measuring 2 cm in height, RoboBee is a small flying robot designed for aerial surveillance. Because keeping an aerial drone aloft requires so much energy, Moritz Alexander Graule of MIT and his colleagues added an electrostatic pad, which acts as a switchable adhesive to allow the device to perch on nearly any material, including glass, wood, and plant leaves. In that way it can continue to deliver aerial views over a wide terrain while consuming three orders of magnitude less power. Although their preliminary model must remain tethered to a nearby power source, the researchers are working to develop an onboard battery pack.

David J. C. MacKay

20 May 2016

California lifts water restrictions

19 May 2016
New York Times: The mandatory water restrictions imposed by the state of California over the past year have now been suspended. In April 2015 California’s governor Jerry Brown was forced to issue the mandate because of the severe drought that had dragged on for the previous four years. Relief came this year in the form of El Niño. Although weaker than predicted, the El Niño event brought enough precipitation to partly fill reservoirs and replenish mountain snowpacks. Residents are not out of the woods yet: The next three years are expected to continue to be unusually dry. Therefore, as of 1 June, communities are being asked to set their own water-restriction guidelines based on local water projections.

Breakthrough Starshot started with a bang

19 May 2016
Extra Dimensions: The Chelyabinsk meteor helped make the interstellar mission possible; major leaps in laser technology will be needed to make it doable.

How lasers can shoot us to the stars

19 May 2016
Before dismissing the ambitious Breakthrough Starshot mission, consider that past performance may be indicative of future results.

Ocean pressure gauges monitor a slow-slip earthquake

19 May 2016
The sensors yield the first detailed measurement of centimeter-scale deformation of the seafloor.

Tsunamis from meteor impacts may have significantly altered Martian landscape

19 May 2016
Science News: Although evidence suggests that Mars's northern lowlands were covered by an ocean 3.4 billion years ago, critics point out the lack of shoreline features. Now Alexis Rodriguez of the Planetary Science Institute in Tucson, Arizona, and his colleagues believe that tsunamis from meteor impacts could have removed such features. Rodriguez's team examined imagery of Mars's surface and identified evidence of at least two tsunamis with wave heights up to 120 m that occurred a few million years apart. The researchers believe that the first tsunami explains the unusual locations of massive boulders and the presence of large backwash channels on the Martian surface. The second tsunami appears to have occurred after Mars's atmosphere cooled, so the water displaced by the tsunami froze in place; Rodriguez says the ice formations could provide information about the chemical makeup of the ancient ocean. Confirming the tsunami theory would probably require an on-the-ground mission to examine various structures up close.

Buzz Aldrin criticizes NASA's approach to reaching Mars

19 May 2016
Ars Technica: At this week's Humans to Mars conference, Buzz Aldrin publicly criticized NASA's Space Launch System (SLS) rocket, Orion spacecraft, and "Journey to Mars" plan for the next 20 years of crewed planetary exploration. Aldrin, who joined NASA in 1963 as part of the agency's third astronaut class, has previously been less critical of NASA's recent efforts. In his speech he criticized the SLS as a project that competes with private-sector efforts and is based on 1970s-era technology instead of more modern developments. He also described the Orion spacecraft as having marginal utility for transporting astronauts to Mars. Aldrin suggested that NASA should change its operational model so that it could focus on developing innovative and game-changing technologies for problems and tasks that do not have modern solutions. Desirable goals include refueling in space and on the surface of the Moon or Mars and harvesting ice from planetary bodies.

Jack G. Dodd, Jr.

18 May 2016

CSIRO staff layoffs include leading sea-level researcher

18 May 2016
New York Times: Despite a controversial staff cut at Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) earlier this year, even more positions are soon going to be eliminated. Among the people who have been given notice is John Church, a leading researcher studying the causes and effects of sea-level change. On 17 May, Church said that CSIRO was consolidating the teams studying the effects of sea-level change and that he was being laid off. CSIRO did not confirm Church's claim. A total of 275 research positions are to be cut, as CSIRO shifts its focus to finding solutions for dealing with the changing climate. In a petition, 3000 researchers from around the world indicated the staff cuts would result in a loss of active research and monitoring information that will hurt the global effort to predict the effects of climate change.

Google AI programmed to produce its own sentences

18 May 2016
Guardian: A new algorithm is being tested by Google that enables artificial-intelligence software to generate grammatically correct sentences. After analyzing thousands of romance novels, the system was given a starting and an ending sentence and then was asked to create its own sentences to fill in the gap. Called a recurrent neural network language model, the technique has had rather poetical results of a dozen or so sentences that resemble free verse because of their grammatical sense and common themes. Such software could have many uses, including image captioning and translation.

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