The vast muddy expanses of the abyssal plains occupy about 60 percent of the Earth's surface and are important in global carbon cycling. Based on long-term studies of two such areas, a new paper in the Proceedings of the National Academy of Sciences (PNAS) shows that animal communities on the abyssal seafloor are affected in a variety of ways by climate change.
Earth
Radiation dose delivered to the prostate and nearby organs in every brachytherapy procedure should be carefully analyzed using post-implant CT or MRI and uniformly documented in every patient, according to a new guideline co-authored by Yan Yu, Ph.D., director of Medical Physics in the department of Radiation Oncology at Thomas Jefferson University.
The guideline was issued by a task group commissioned by the American Association of Physicists in Medicine (AAPM), and will be published in the November 2009 issue of Medical Physics.
COLLEGE PARK, Md. -- Most land use changes occurring in the continental U.S result in raised regional surface temperatures, says a new study by scientists at the University of Maryland, Purdue University and the University of Colorado in Boulder.
In 2005, a gigantic, 35-mile-long rift broke open the desert ground in Ethiopia. At the time, some geologists believed the rift was the beginning of a new ocean as two parts of the African continent pulled apart, but the claim was controversial.
Now, scientists from several countries have confirmed that the volcanic processes at work beneath the Ethiopian rift are nearly identical to those at the bottom of the world's oceans, and the rift is indeed likely the beginning of a new sea.
Proton beam therapy can be safely delivered to men with prostate cancer and has minimal urinary and rectal side effects, according to a study presented November 2, 2009, at the American Society for Radiation Oncology's 51st Annual Meeting in Chicago.
Researchers sought to determine if delivering higher doses of radiation with proton therapy would cause early harmful side effects to urinary function within the genitourinary system (GU) function and rectal function within the gastrointestinal (GI) system.
Men who receive a "boost" of proton therapy after receiving a standard course of X-ray radiation therapy have fewer recurrences of their prostate cancer compared to men who did not receive the extra dose of proton radiation, according to a first-of-its-kind study presented November 2, 2009, at the American Society for Radiation Oncology's 51st Annual Meeting in Chicago. The multi-institutional, randomized trial also shows that the high dose treatment is safe for these patients and causes no severe problems later with urinary or bowel functions.
Scientists including researchers from the National Oceanography Centre, Southampton and the University of Essex have discovered that interactions between iron supply, transported through the atmosphere from deserts, and large-scale oceanic circulation control the availability of a crucial nutrient, nitrogen, in the Atlantic. Their findings have potentially important implications for understanding global climate, both past and future.
The LCLS is a testament to SLAC's continued leadership in accelerator technology. Over 40 years ago, the laboratory's two-mile linear accelerator, or linac, was built to study the fundamental building blocks of the universe. Now, decades later, this same machine has been revitalized for frontier research underway at the LCLS.
In the quest to produce nuclear fusion energy, researchers from the DIII-D National Fusion Facility have recently confirmed long-standing theoretical predictions that performance, efficiency and reliability are simultaneously obtained in tokamaks, the leading magnetic confinement fusion device, operating at their performance limits. Experiments designed to test these predictions have successfully demonstrated the interaction of these conditions.
For decades, climate scientists have worked to identify and measure key substances -- notably greenhouse gases and aerosol particles -- that affect Earth's climate. And they've been aided by ever more sophisticated computer models that make estimating the relative impact of each type of pollutant more reliable.
RIVERSIDE, Calif. – Scientists widely accept that around 2.4 billion years ago, the Earth's atmosphere underwent a dramatic change when oxygen levels rose sharply. Called the "Great Oxidation Event" (GOE), the oxygen spike marks an important milestone in Earth's history, the transformation from an oxygen-poor atmosphere to an oxygen-rich one paving the way for complex life to develop on the planet.
LOS ALAMOS, New Mexico, October 29, 2009— Very tiny wires, called nanowires, made from such metals as silver and gold, may play a crucial role as electrical or mechanical switches in the development of future-generation ultrasmall nanodevices.
Making nanodevices work will require a deep understanding of how these and other nanostructures can be engineered and fabricated as well as their resultant strengths and weaknesses. How mechanical properties change at the nanoscale is of fundamental interest and may have implications for a variety of nanostructures and nanodevices.
LOS ALAMOS, New Mexico, Oct 28, 2009— For years scientists have struggled with the difficult physics of inertial confinement fusion. This is the attempt to compress a target capsule containing isotopes of hydrogen with high-powered lasers to high enough pressure and temperature to initiate fusion burn.
To achieve fusion scientists must put as much laser energy on target as possible, a task complicated by energy loss due to laser backscatter, or reflection. Fusion is the basic energy-producing process of the sun, and is a source of energy released by nuclear weapons.
Tsunamis are among the most-devastating natural calamities. These earthquake-generated waves can quickly engulf low-lying land and bring widespread destruction and death. They can deposit sand and debris far inland from where they came ashore.
Now, for the first time, a group of scientists working in the Kuril Islands off the east coast of Russia has documented the scope of tsunami-caused erosion and found that a wave can carry away far more sand and dirt than it deposits.
Fossil land snail shells found in ancient soils on the subtropical eastern Canary Islands show that the Spanish archipelago off the northwest coast of Africa has become progressively drier over the past 50,000 years.