848 research outputs found
Many-Task Computing and Blue Waters
This report discusses many-task computing (MTC) generically and in the
context of the proposed Blue Waters systems, which is planned to be the largest
NSF-funded supercomputer when it begins production use in 2012. The aim of this
report is to inform the BW project about MTC, including understanding aspects
of MTC applications that can be used to characterize the domain and
understanding the implications of these aspects to middleware and policies.
Many MTC applications do not neatly fit the stereotypes of high-performance
computing (HPC) or high-throughput computing (HTC) applications. Like HTC
applications, by definition MTC applications are structured as graphs of
discrete tasks, with explicit input and output dependencies forming the graph
edges. However, MTC applications have significant features that distinguish
them from typical HTC applications. In particular, different engineering
constraints for hardware and software must be met in order to support these
applications. HTC applications have traditionally run on platforms such as
grids and clusters, through either workflow systems or parallel programming
systems. MTC applications, in contrast, will often demand a short time to
solution, may be communication intensive or data intensive, and may comprise
very short tasks. Therefore, hardware and software for MTC must be engineered
to support the additional communication and I/O and must minimize task dispatch
overheads. The hardware of large-scale HPC systems, with its high degree of
parallelism and support for intensive communication, is well suited for MTC
applications. However, HPC systems often lack a dynamic resource-provisioning
feature, are not ideal for task communication via the file system, and have an
I/O system that is not optimized for MTC-style applications. Hence, additional
software support is likely to be required to gain full benefit from the HPC
hardware
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Pericardial rupture leading to cardiac herniation after blunt trauma.
Pericardial rupture with cardiac herniation is a rare traumatic injury with an estimated incidence of 0.37% after blunt trauma. Most commonly occurring after high-speed impact, such as in motor vehicle or motorcycle collisions, pericardial rupture is associated with a high mortality rate. Radiologic diagnosis can be challenging; cross-sectional imaging findings can be suggestive of pericardial rupture but are often non-specific, and echocardiography windows are often obscured. Definitive diagnosis is generally made intra-operatively. Treatment involves reduction of the heart into normal anatomic position with repair of the pericardium, either primarily or with a patch. Fewer than 60 cases of pericardial rupture from blunt trauma have been reported in the literature. We describe a 65Â year old poly-trauma patient who sustained pericardial rupture with subsequent cardiac herniation with cardiovascular collapse, and we discuss the considerations and complexities of his successful repair
An Electrochemical Cell for the Efficient Turn Around of Wafer Working Electrodes
We present a new design for an electrochemical cell for use with wafer working electrodes. The key feature of the design is the use of half turn thumb screws to form a liquid-tight seal between an o-ring and the sample surface. The assembly or disassembly of the cell requires a half turn of each thumb screw, which facilitates the quick turn around of wafer samples. The electrochemical performance of the cell is demonstrated by cyclic voltammetry and double step chronoamperometry measurements of the ferricyanide/ferrocyanide couple
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Family-based association study of the BDNF, COMT and serotonin transporter genes and DSM-IV bipolar-I disorder in children
Background: Over the past decade pediatric bipolar disorder has gained recognition as a potentially more severe and heritable form of the disorder. In this report we test for association with genes coding brain-derived neurotrophic factor (BDNF), the serotonin transporter (SLC6A4), and catechol-O-methyltransferase (COMT). Methods: Bipolar-I affected offspring triads (N = 173) were drawn from 522 individuals with 2 parents in 332 nuclear families recruited for genetic studies of pediatric psychopathology at the Clinical and Research Program in Pediatric Psychopharmacology and Adult ADHD at Massachusetts General Hospital. Results: We failed to identify an association with the val66 allele in BDNF (OR = 1.23, p = 0.36), the COMT-l allele (OR = 1.27, p = 0.1), or the HTTLPR short allele (OR = 0.87, p = 0.38). Conclusion: Our study suggests that the markers examined thus far in COMT and SLC6A4 are not associated with pediatric bipolar disorder and that if the val66met marker in BDNF is associated with pediatric bipolar disorder the magnitude of the association is much smaller than first reported
Treatment Longevity and Changes in Surface Fuel Loads After PinyonâJuniper Mastication
In the Intermountain West, land managers masticate pinyon pine (Pinus spp.) and juniper (Juniperus spp.) trees that have encroached sagebrush steppe communities to reduce canopy fuels, alter potential fire behavior, and promote growth of understory grasses, forbs, and shrubs. At three study sites in Utah, 45 sampling plots spanning a range of tree cover from 5% to 50% were masticated. We measured surface fuel load components three times over a 10âyr period. We also measured tree cover, density, and height as indicators of treatment longevity. Changes in these variables were analyzed across the range of preâtreatment tree cover using linear mixed effects modeling. We detected decreases in 1âh down woody debris by 5â6 yr postâtreatment, and from 5â6 to 10 yr postâtreatment, but did not detect changes in 10âh or 100 + 1000âh down woody debris. By 10 yr postâtreatment, there was very little duff and tree litter left for all preâtreatment tree cover values. Herbaceous fuels (all standing live and dead biomass) increased through 10 yr postâtreatment. At 10 yr postâtreatment, pinyonâjuniper cover ranged 0â2.6%, and the majority of trees were1âh fuels were the only class of down woody debris that decreased, it may be beneficial to masticate woody fuels to the finest size possible. Decreases in 1âh down woody debris and duff + litter fuels over time may have important implications for fire behavior and effects, but increases in herbaceous and shrub fuel loads should also be taken into account. At 10 yr postâtreatment, understory grasses and shrubs were not being outcompeted by trees, and average pinyonâjuniper canopy cover wa
Analysis of Electrodeposited Nickel-Iron Alloy Film Composition Using Particle-Induced X-Ray Emission
The elemental composition of electrodeposited NiFe thin films was analyzed with particle-induced X-ray emission (PIXE). The thin films were electrodeposited on polycrystalline Au substrates from a 100mM NiSO4, 10 mM FeSO4, 0.5M H3BO3, and 1M Na2SO4 solution. PIXE spectra of these films were analyzed to obtain relative amounts of Ni and Fe as a function of deposition potential and deposition time. The results show that PIXE can measure the total deposited metal in a sample over at least four orders of magnitude with similar fractional uncertainties. The technique is also sensitive enough to observe the variations in alloy composition due to sample nonuniformity or variations in deposition parameters
Prediction of invasive candidal infection in critically ill patients with severe acute pancreatitis
Evaluation of self-reported ethnicity in a case-control population: the stroke prevention in young women study
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