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Institution

University of Massachusetts Amherst

EducationAmherst Center, Massachusetts, United States
About: University of Massachusetts Amherst is a education organization based out in Amherst Center, Massachusetts, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 37274 authors who have published 83965 publications receiving 3834996 citations. The organization is also known as: UMass Amherst & Massachusetts State College.


Papers
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Journal ArticleDOI
10 Jan 2003-Science
TL;DR: A photoinduced transformation is described in which nanoparticles, initially soluble only in toluene, were transported across an interface into water and were dispersed in the water phase, providing a direct probe of their spatial distribution.
Abstract: The self-assembly of particles at fluid interfaces, driven by the reduction in interfacial energy, is well established. However, for nanoscopic particles, thermal fluctuations compete with interfacial energy and give rise to a particle-size-dependent self-assembly. Ligand-stabilized nanoparticles assembled into three-dimensional constructs at fluid-fluid interfaces, where the properties unique to the nanoparticles were preserved. The small size of the nanoparticles led to a weak confinement of the nanoparticles at the fluid interface that opens avenues to size-selective particle assembly, two-dimensional phase behavior, and functionalization. Fluid interfaces afford a rapid approach to equilibrium and easy access to nanoparticles for subsequent modification. A photoinduced transformation is described in which nanoparticles, initially soluble only in toluene, were transported across an interface into water and were dispersed in the water phase. The characteristic fluorescence emission of the nanoparticles provided a direct probe of their spatial distribution.

935 citations

Proceedings Article
11 Apr 2007
TL;DR: This work presents Sandpiper, a system that automates the task of monitoring and detecting hotspots, determining a new mapping of physical to virtual resources and initiating the necessary migrations, and implements a black- box approach that is fully OS- and application-agnostic and a gray-box approach that exploits OS-and- application-level statistics.
Abstract: Virtualization can provide significant benefits in data centers by enabling virtual machine migration to eliminate hotspots. We present Sandpiper, a system that automates the task of monitoring and detecting hotspots, determining a new mapping of physical to virtual resources and initiating the necessary migrations. Sandpiper implements a black-box approach that is fully OS- and application-agnostic and a gray-box approach that exploits OS- and application-level statistics. We implement our techniques in Xen and conduct a detailed evaluation using a mix of CPU, network and memory-intensive applications. Our results show that Sandpiper is able to resolve single server hotspots within 20 seconds and scales well to larger, data center environments. We also show that the gray-box approach can help Sandpiper make more informed decisions, particularly in response to memory pressure.

931 citations

Journal ArticleDOI
19 Mar 2009-Nature
TL;DR: A combined ice sheet/ice shelf model capable of high-resolution nesting with a new treatment of grounding-line dynamics and ice-shelf buttressing is used to simulate Antarctic ice sheet variations over the past five million years, indicating a long-term trend from more frequently collapsed to more glaciated states.
Abstract: Changes in Earth's orbit are known to influence climate shifts from cold glacials to warm interglacials. How the vast West Antarctic ice sheet responds to these fluctuations is uncertain but, because its collapse could raise sea levels by about 5 metres, of great interest. Naish et al. have analysed the AND-1B ocean sediment core, extracted from beneath the Ross Ice Shelf as part of the ANDRILL drilling project, and find evidence that the ice sheet collapsed periodically during the early Pliocene (3-5 million years ago), when atmospheric CO2 levels were similar to, or slightly higher than today's. The pattern of collapse suggests an influence of approximately 40,000-year cycles in the tilt of Earth's rotational axis (obliquity). Also in this issue of Nature, in a numerical modelling study focused on the past 5 million years in Antarctica, David Pollard and Robert DeConto combine ice sheet (land-supported) and ice shelf (water-supported) modelling approaches to simulate the movement of the grounding line — the border between land and sea ice. Their results show that over the past 5 million years, the West Antarctic ice sheet transitioned between full, intermediate, and collapsed states in just a few thousand years. This means that the ice sheet is likely to disintegrate if ocean temperatures in the area rise by 5 C. If the West Antarctic Ice Sheet (WAIS) melted, sea levels would rise by about 5 m; such changes are thought to have occurred in the past but could not be simulated by models. Pollard and DeConto combine ice-sheet with ice-shelf modelling, and show that over the past 5 million years, the WAIS transitioned among full, intermediate, and collapsed states in only a few thousand years, suggesting possible disintegration of the WAIS if ocean temperatures in the area rise by 5 °C. The West Antarctic ice sheet (WAIS), with ice volume equivalent to ∼5 m of sea level1, has long been considered capable of past and future catastrophic collapse2,3,4. Today, the ice sheet is fringed by vulnerable floating ice shelves that buttress the fast flow of inland ice streams. Grounding lines are several hundred metres below sea level and the bed deepens upstream, raising the prospect of runaway retreat3,5. Projections of future WAIS behaviour have been hampered by limited understanding of past variations and their underlying forcing mechanisms6,7. Its variation since the Last Glacial Maximum is best known, with grounding lines advancing to the continental-shelf edges around ∼15 kyr ago before retreating to near-modern locations by ∼3 kyr ago8. Prior collapses during the warmth of the early Pliocene epoch9 and some Pleistocene interglacials have been suggested indirectly from records of sea level and deep-sea-core isotopes, and by the discovery of open-ocean diatoms in subglacial sediments10. Until now11, however, little direct evidence of such behaviour has been available. Here we use a combined ice sheet/ice shelf model12 capable of high-resolution nesting with a new treatment of grounding-line dynamics and ice-shelf buttressing5 to simulate Antarctic ice sheet variations over the past five million years. Modelled WAIS variations range from full glacial extents with grounding lines near the continental shelf break, intermediate states similar to modern, and brief but dramatic retreats, leaving only small, isolated ice caps on West Antarctic islands. Transitions between glacial, intermediate and collapsed states are relatively rapid, taking one to several thousand years. Our simulation is in good agreement with a new sediment record (ANDRILL AND-1B) recovered from the western Ross Sea11, indicating a long-term trend from more frequently collapsed to more glaciated states, dominant 40-kyr cyclicity in the Pliocene, and major retreats at marine isotope stage 31 (∼1.07 Myr ago) and other super-interglacials.

931 citations

Journal ArticleDOI
TL;DR: In this paper, a nonexponential empirical model was proposed to predict moisture contents after long exposure from experimental data obtained in relatively short time, i.e., well before the moisture level appeared to reach a plateau.
Abstract: Published sorption curves in the form of moisture vs time relationships of milk powder and rice, exposed to moist atmosphere or soaked In water, were fitted by a two parameter, nonexponential empirical model. The model enabled prediction of moisture contents after long exposure from experimental data obtained in relatively short time, i.e., well before the moisture level appeared to reach a plateau. The model implied that the moisture equilibrium was somewhat higher than that determined on the assumption that the sample reached a constant weight, but there was no conclusive evidence that this was really the case.

930 citations

Journal ArticleDOI
TL;DR: The work-family role system as discussed by the authors is composed of the male work role, the female work role and the female family role, and the male family role may be fully actualized, or may be only partly actualized or latent.
Abstract: The study of work and the study of the family have traditionally constituted separate sub-disciplines in sociology. Rapoport and Rapoport (1965) and Kanter (1976), among others, have aptly stressed the need for greater examination of work and family roles in relation to each other. Such joint consideration is necessary to describe how individuals' functioning in either of these spheres is affected by their involvement in the other. Further, the current examination of sex roles brings added impetus to the analysis of work-family interrelationships. A major part of what is usually meant by change in "sex roles" is specifically change in the traditional allocation of work and family roles between men and women. Traditional sex role norms prescribed the specialization of work and family responsibilities by sex, but a new option for each sex to integrate roles in both work and the family is now emerging. This paper analyzes some aspects of what I term the "work-family role system." The work-family role system is composed of the male work role, the female work role, the female family role, and the male family role. Each of these roles may be fully actualized, or may be only partly actualized or latent, as is often the case with the female work role and the male family role. The analysis of these four roles as a system provides a useful way of organizing research about the relations among these roles, and suggests new relations to be examined. It also makes possible some inferences about the dynamics of future changes in women's and men's roles in work and the family. Analyzing men's and women's work and family roles as components of a role system involves specifying how each role articulates with the others to which it is linked, and how variations in the nature of each role, or whether the role is actualized at all, affects the others. For example, to describe the link between the female work and the female family roles, we consider how the extent of the female work role (ranging from no paid work at all, to the most demanding and highest status full time work) both affects and is affected by the extent of the female family role. These links can be considered at two conceptual levels. They can be analyzed at the level of the individual couple, e.g., the relation between wives' employment status and wives' role performance in the family. Each link can also be considered at the

927 citations


Authors

Showing all 37601 results

NameH-indexPapersCitations
George M. Whitesides2401739269833
Joan Massagué189408149951
David H. Weinberg183700171424
David L. Kaplan1771944146082
Michael I. Jordan1761016216204
James F. Sallis169825144836
Bradley T. Hyman169765136098
Anton M. Koekemoer1681127106796
Derek R. Lovley16858295315
Michel C. Nussenzweig16551687665
Alfred L. Goldberg15647488296
Donna Spiegelman15280485428
Susan E. Hankinson15178988297
Bernard Moss14783076991
Roger J. Davis147498103478
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
2023103
2022535
20213,983
20203,858
20193,712
20183,385