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A new, lower value of total solar irradiance: Evidence and climate significance - Kopp - 2011 - Geophysical Research Letters Abstract [1] The most accurate value of total solar irradiance during the 2008 solar minimum period is 1360.8 ± 0.5 W m−2 according to measurements from the Total Irradiance Monitor (TIM) on NASA's Solar Radiation and Climate Experiment (SORCE) and a series of new radiometric laboratory tests. This value is significantly lower than the canonical value of 1365.4 ± 1.3 W m−2 established in the 1990s, which energy balance calculations and climate models currently use. Scattered light is a primary cause of the higher irradiance values measured by the earlier generation of solar radiometers in which the precision aperture defining the measured solar beam is located behind a larger, view-limiting aperture. In the TIM, the opposite order of these apertures precludes this spurious signal by limiting the light entering the instrument.

A Tour of Machine Learning Algorithms Originally published by Jason Brownlee in 2013, it still is a goldmine for all machine learning professionals. The algorithms are broken down in several categories. Here we provide a high-level summary, a much longer and detailed version can be found here. You can even download an algorithm map from the original article. Below is a much smaller version. Solar irradiance Solar irradiance is the power per unit area produced by the Sun in the form of electromagnetic radiation. Irradiance may be measured in space or at the Earth's surface after atmospheric absorption and scattering. Total Solar Irradiance (TSI), is a measure of the solar radiative power per unit area normal to the rays, incident on the Earth's upper atmosphere. The solar constant is a conventional measure of mean TSI at a distance of one astronomical Unit (AU).

Problem Book in Relativity and Gravitation Beloved by a generation of students of General Relativity, the Problem Book in Relativity and Gravitation, by Alan P. Lightman, William H. Press, Richard H. Price, and Saul A. Quantum physics just got less complicated Here's a nice surprise: quantum physics is less complicated than we thought. An international team of researchers has proved that two peculiar features of the quantum world previously considered distinct are different manifestations of the same thing. The result is published 19 December in Nature Communications. Patrick Coles, Jedrzej Kaniewski, and Stephanie Wehner made the breakthrough while at the Centre for Quantum Technologies at the National University of Singapore.

Parallel Universes: Theories & Evidence Is our universe unique? From science fiction to science fact, there is a proposal out there that suggests that there could be other universes besides our own, where all the choices you made in this life played out in alternate realities. So, instead of turning down that job offer that took you from the United States to China, the alternate universe would show the outcome if you decided to venture to Asia instead. The idea is pervasive in comic books and movies. For example, in the 2009 "Star Trek" reboot, the premise is that the Kirk and Spock portrayed by Chris Pine and Zachary Quinto are in an alternate timeline apart from the William Shatner and Leonard Nimoy versions of the characters. The concept is known as a "parallel universe," and is a facet of the astronomical theory of the multiverse.

Physicists achieve superconductivity at room temperature Medical scientists have developed a new chemical compound that’s been shown to treat spinal cord injuries of 80 percent of the animals it was tested on. The compound, which they’re calling intracellular sigma peptide (ISP), was tested on 26 animals who were paralysed due to a spinal cord injury - and in 21 cases the animals were able to urinate, move, or both after seven weeks of treatment. "This recovery is unprecedented," said neuroscientist Jerry Silver from Case Western Reserve University, who led the research, in a press release. "Each of the 21 animals got something back in terms of function. For any spinal cord-injured patient today, it would be considered extraordinary to regain even one of these functions, especially bladder function. After a spinal cord injury, people become paralysed as a result of scar tissue that builds up and stops nerve cells from connecting with each other.

Hawking at Harvard Black holes have long been painted as eternal prisons, regions of space so dense that nothing — not even light — can escape them. But the truth, Stephen Hawking told a packed Sanders Theatre this afternoon, is that the holes aren’t as black as you might think. In a session that was the hottest ticket on campus in some time, the renowned Cambridge theoretical physicist and cosmologist spoke to more than 1,000 faculty, students, and staff at Sanders, with dozens more watching at simulcast sites in the Science Center and at Jefferson Lab. Hawking’s lecture focused on his research into black holes and the information paradox, which suggests that physical information is permanently lost in such holes, a controversial notion that violates the scientific tenet that information about a system from one time can be used to understand its state at any other time. “It is said that fact is sometimes stranger than fiction, and nowhere is that more true than in the case of black holes,” Hawking said.

Mars Up Close Marc Kaufman Marc Kaufman is a science writer and national editor for The Washington Post. He lives outside of Washington, D.C. Visit him at - See more at: Dr. Matthew P.