Rapidly growing lakes in deglaciating mountain regions represent both: emerging risks and options for human livelihoods. In the Andes of Peru, seasonal water scarcity and Glacial Lake Outburst Floods (GLOF) pose a serious threat for highly exposed and vulnerable people. In addition, water demand is growing due to increasing irrigated agriculture, population and hydropower production.
View Article and Find Full Text PDFGlaciers have strongly contributed to sea-level rise during the past century and will continue to be an important part of the sea-level budget during the twenty-first century. Here, we review the progress in estimating global glacier mass change from in situ measurements of mass and length changes, remote sensing methods, and mass balance modeling driven by climate observations. For the period before the onset of satellite observations, different strategies to overcome the uncertainty associated with monitoring only a small sample of the world's glaciers have been developed.
View Article and Find Full Text PDFPhilos Trans A Math Phys Eng Sci
May 2010
The number of large slope failures in some high-mountain regions such as the European Alps has increased during the past two to three decades. There is concern that recent climate change is driving this increase in slope failures, thus possibly further exacerbating the hazard in the future. Although the effects of a gradual temperature rise on glaciers and permafrost have been extensively studied, the impacts of short-term, unusually warm temperature increases on slope stability in high mountains remain largely unexplored.
View Article and Find Full Text PDFWe report the first precision measurement of the proton electric to magnetic form factor ratio from spin-dependent elastic scattering of longitudinally polarized electrons from a polarized hydrogen internal gas target. The measurement was performed at the MIT-Bates South Hall Ring over a range of four-momentum transfer squared Q2 from 0.15 to 0.
View Article and Find Full Text PDFThe Brookhaven Relativistic Heavy Ion Collider (RHIC) has been providing collisions of polarized protons at a beam energy of 100 GeV since 2001. Equipped with two full Siberian snakes in each ring, polarization is preserved during acceleration from injection to 100 GeV. However, the intrinsic spin resonances beyond 100 GeV are about a factor of 2 stronger than those below 100 GeV making it important to examine the impact of these strong intrinsic spin resonances on polarization survival and the tolerance for vertical orbit distortions.
View Article and Find Full Text PDFHigh-mountain areas suffer from increasing environmental threats. The causes are often global in dimension but lead to specific impacts under conditions of steep and/or high-altitude terrain with strong effects from snow and ice. This paper presents a global perspective, focussing primarily on observed and projected changes in climate and then goes on to discuss key messages of greatest relevance to the highest belts of mountain regions.
View Article and Find Full Text PDFThe transverse polarization of electrons emitted in the beta decay of polarized 8Li nuclei has been measured. For the time-reversal violating triple correlation parameter we find R=(0.9+/-2.
View Article and Find Full Text PDFSpin-dependent lepton-nucleon scattering data have been used to investigate the validity of the concept of quark-hadron duality for the spin asymmetry A1. Longitudinally polarized positrons were scattered off a longitudinally polarized hydrogen target for values of Q2 between 1.2 and 12 GeV2 and values of W2 between 1 and 4 GeV2.
View Article and Find Full Text PDFExclusive coherent and incoherent electroproduction of the rho(0) meson from 1H and 14N targets has been studied at the HERMES experiment as a function of coherence length (l(c)), corresponding to the lifetime of hadronic fluctuations of the virtual photon, and squared four-momentum of the virtual photon (-Q2). The ratio of 14N to 1H cross sections per nucleon, called nuclear transparency, was found to increase (decrease) with increasing l(c) for coherent (incoherent) rho(0) electroproduction. For fixed l(c), a rise of nuclear transparency with Q2 is observed for both coherent and incoherent rho(0) production, which is in agreement with theoretical calculations of color transparency.
View Article and Find Full Text PDFThe nuclear polarization of H(2) molecules formed by recombination of polarized H atoms on a Cu surface was measured as a function of external magnetic field and of temperature of the surface. The proton polarization of the molecules was determined by scattering of a longitudinally polarized 203-MeV proton beam in the Indiana University Cyclotron Facility storage ring. The nuclear polarization of the molecules, relative to the polarization of the atoms before recombination, increased from near zero in a weak magnetic field to 0.
View Article and Find Full Text PDFPhys Rev C Nucl Phys
August 1994
Phys Rev C Nucl Phys
January 1992