969 research outputs found
Health care resouce use and stroke outcome
Background and Purpose: Outcome in patients hospitalized for acute stroke varies considerably between populations. Within the framework of the GAIN International trial, a large multicenter trial of a neuroprotective agent (gavestinel, glycine antagonist), stroke outcome in relation to health care resource use has been compared in a large number of countries, allowing for differences in case mix. Methods: This substudy includes 1,422 patients in 19 countries grouped into 10 regions. Data on prognostic variables on admission to hospital, resource use, and outcome were analyzed by regression models. Results: All results were adjusted for differences in prognostic factors on admission (NIH Stroke Scale, age, comorbidity). There were threefold variations in the average number of days in hospital/institutional care (from 20 to 60 days). The proportion of patients who met with professional rehabilitation staff also varied greatly. Three-month case fatality ranged from 11% to 28%, and mean Barthel ADL score at three months varied between 64 and 73. There was no relationship between health care resource use and outcome in terms of survival and ADL function at three months. The proportion of patients living at home at three months did not show any relationship to ADL function across countries. Conclusions: There are wide variations in health care resource use between countries, unexplained by differences in case mix. Across countries, there is no obvious relationship between resource use and clinical outcome after stroke. Differences in health care traditions (treatment pathways) and social We thank the coinvestigators and research staff at the participating centers for their support. Glaxo Wellcome sponsored the GAIN International trial, supported the present analyses and reviewed the final draft of the article
Coronal heating in multiple magnetic threads
Context. Heating the solar corona to several million degrees requires the
conversion of magnetic energy into thermal energy. In this paper, we
investigate whether an unstable magnetic thread within a coronal loop can
destabilise a neighbouring magnetic thread. Aims. By running a series of
simulations, we aim to understand under what conditions the destabilisation of
a single magnetic thread can also trigger a release of energy in a nearby
thread. Methods. The 3D magnetohydrodynamics code, Lare3d, is used to simulate
the temporal evolution of coronal magnetic fields during a kink instability and
the subsequent relaxation process. We assume that a coronal magnetic loop
consists of non-potential magnetic threads that are initially in an equilibrium
state. Results. The non-linear kink instability in one magnetic thread forms a
helical current sheet and initiates magnetic reconnection. The current sheet
fragments, and magnetic energy is released throughout that thread. We find
that, under certain conditions, this event can destabilise a nearby thread,
which is a necessary requirement for starting an avalanche of energy release in
magnetic threads. Conclusions. It is possible to initiate an energy release in
a nearby, non-potential magnetic thread, because the energy released from one
unstable magnetic thread can trigger energy release in nearby threads, provided
that the nearby structures are close to marginal stability
"Stay at Home and Live with Integrity": Advice to German Emigrants to the United States from the Journeymen’s Father
In recent decades, American historians have asserted that a broad chasm existed between the rhetoric of equality in Jacksonian America and the actual economic reality that existed. Several years ago, Edward Pessen observed that the so-called Era of the Common Man brought no startling social or economic improvements for the common sort of people. More recently, authors like Alan Dawley, Paul E. Johnson, and Sean Wilentz have argued that not only was there no improvement in the conditions for working men, but the universe of options for skilled journeymen was undergoing a radical contraction, which endangered their integrity as an independent productive class.* Furthermore, eroding economic conditions seem to have led to a decline in the commitment to democratic ideology. Michael Holt posits that economic dislocation of the artisan class as a result of the industrial revolution and increased pressure for jobs created by rising immigration led many Americans to support programs which were designed to reduce immigration, or at least to reduce the political influence of incoming immigrants. This support resulted in the rise of such antidemocratic organizations as the nativist societies which eventually formed the American Know-Nothing party.
Stay at Home and Live with Integrity : Advice to German Emigrants to the United States from the Journeymen’s Father
In recent decades, American historians have asserted that a broad chasm existed between the rhetoric of equality in Jacksonian America and the actual economic reality that existed. Several years ago, Edward Pessen observed that the so-called Era of the Common Man brought no startling social or economic improvements for the common sort of people. More recently, authors like Alan Dawley, Paul E. Johnson, and Sean Wilentz have argued that not only was there no improvement in the conditions for working men, but the universe of options for skilled journeymen was undergoing a radical contraction, which endangered their integrity as an independent productive class.* Furthermore, eroding economic conditions seem to have led to a decline in the commitment to democratic ideology. Michael Holt posits that economic dislocation of the artisan class as a result of the industrial revolution and increased pressure for jobs created by rising immigration led many Americans to support programs which were designed to reduce immigration, or at least to reduce the political influence of incoming immigrants. This support resulted in the rise of such antidemocratic organizations as the nativist societies which eventually formed the American Know-Nothing party.
Structures in the outer solar atmosphere
The structure and dynamics of the outer solar atmosphere are reviewed with
emphasis on the role played by the magnetic field. Contemporary observations
that focus on high resolution imaging over a range of temperatures, as well as
UV, EUV and hard X-ray spectroscopy, demonstrate the presence of a vast range
of temporal and spatial scales, mass motions, and particle energies present. By
focussing on recent developments in the chromosphere, corona and solar wind, it
is shown that small scale processes, in particular magnetic reconnection, play
a central role in determining the large-scale structure and properties of all
regions. This coupling of scales is central to understanding the atmosphere,
yet poses formidable challenges for theoretical models.Comment: 41 Pages, 15 Figures, Accepted for publication in Space Science
Review
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The Influence of Lithology on Stream Metabolism in Mountain Systems
Physical disturbance in streams has important effects on the metabolic rates of gross primary production (GPP) and ecosystem respiration (ER). Underlying lithology can control sediment size, amount, and evolution in the stream, influencing substrate stability and its effect on benthic organisms. We assessed the patterns of disturbance and recovery of metabolic rates after periods of increased flow and suspended sediment flux in different lithologies. We modeled whole-stream metabolism during the winter-spring period between December and April in two streams in the Oregon Coast Range: one with basalt lithology, and one with sandstone lithology. Our results indicated that the two streams varied in their patterns of response and recovery to storms. Both streams were heterotrophic during the entirety of the study period, but changes in heterotrophy were driven by changes in ER. Post-storm GPP decreased in both streams, but the basalt basin had greater proportional decreases. Decreases were also greater later in the study period, when pre-storm rates of GPP were higher. Rates of ER increased in the basalt basin post-storm and did not change from pre- to post-storm in the sandstone basin. Recovery of GPP was more rapid in the sandstone basin than the basalt basin. The P/R ratio recovery period was similar in both streams, but recovery was faster in the sandstone basin. Overall, our results indicated that the underlying lithology of small mountain streams drives variability in heterotrophy through differing effects on ER
The energetics of the gradual phase
Reseachers compare results with those in the chapter by Moore et al. (1980), who reached five main conclusions about the gradual phase: (1) the typical density of the soft X-ray emitting plasma is between 10 to the 11th power and 10 to the 12th power cm-3 for compact flares and between 10 to the 10th power and 10 to the 11th power cm-3 for a large-area flare; (2) cooling is by conduction and radiation in roughly equal proportions; (3) continual heating is needed in the decay phase of two-ribbon flares; (4) continual heating is probably not needed in compact events; (5) most of the soft-X-ray-emitting plasma results from chromospheric evaporation. The goal was to reexamine these problems with the data from the Solar Maximum Mission (SMM) and other supporting instruments as well as to take advantage of recent theoretical advances. SMM is capable of measuring coronal temperatures more accurately and with a better cadence than has been possible before. The SMM data set is also unique in that the complete transit of an active region was observed, with soft X-ray and UV images being taken every few minutes. Researcher's were therefore able to establish the pre-flare conditions of the region and see whether anything has changed as a result of the flare. The assumptions made in attempting to determine the required plasma parameters are described. The derived parameters for the five prime flares are presented, and the role of numerical simulations is discussed
Flare energetics
In this investigation of flare energetics, researchers sought to establish a comprehensive and self-consistent picture of the sources and transport of energy within a flare. To achieve this goal, they chose five flares in 1980 that were well observed with instruments on the Solar Maximum Mission, and with other space-borne and ground-based instruments. The events were chosen to represent various types of flares. Details of the observations available for them and the corresponding physical parameters derived from these data are presented. The flares were studied from two perspectives, the impulsive and gradual phases, and then the results were compared to obtain the overall picture of the energics of these flares. The role that modeling can play in estimating the total energy of a flare when the observationally determined parameters are used as the input to a numerical model is discussed. Finally, a critique of the current understanding of flare energetics and the methods used to determine various energetics terms is outlined, and possible future directions of research in this area are suggested
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