238 research outputs found
A dynamic data-driven application simulation framework for contaminant transport problems
AbstractWe describe, devise, and augment dynamic data-driven application simulations (DDDAS). DDDAS offers interesting computational and mathematically unsolved problems, such as, how do you analyze, compute, and predict the solution of a generalized PDE when you do not know either where or what the boundary conditions are at any given moment in the simulation in advance? A summary of DDDAS features and why this is a intellectually stimulating new field are included in the paper.We apply the DDDAS methodology to some examples from a contaminant transport problem. We demonstrate that the multiscale interpolation and backward in time error monitoring are useful to long running simulations
Consumption caught in the cash nexus.
During the last thirty years, âconsumptionâ has become a major topic in the study of contemporary culture within anthropology, psychology and sociology. For many authors it has become central to understanding the nature of material culture in the modern world but this paper argues that the concept is, in British writing at least, too concerned with its economic origins in the selling and buying of consumer goods or commodities. It is argued that to understand material culture as determined through the monetary exchange for things - the cash nexus - leads to an inadequate sociological understanding of the social relations with objects. The work of Jean Baudrillard is used both to critique the concept of consumption as it leads to a focus on advertising, choice, money and shopping and to point to a more sociologically adequate approach to material culture that explores objects in a system of models and series, âatmosphereâ, functionality, biography, interaction and mediation
The New Horizons Spacecraft
The New Horizons spacecraft was launched on 19 January 2006. The spacecraft
was designed to provide a platform for seven instruments that will collect and
return data from Pluto in 2015. The design drew on heritage from previous
missions developed at The Johns Hopkins University Applied Physics Laboratory
(APL) and other missions such as Ulysses. The trajectory design imposed
constraints on mass and structural strength to meet the high launch
acceleration needed to reach the Pluto system prior to the year 2020. The
spacecraft subsystems were designed to meet tight mass and power allocations,
yet provide the necessary control and data handling finesse to support data
collection and return when the one-way light time during the Pluto flyby is 4.5
hours. Missions to the outer solar system require a radioisotope thermoelectric
generator (RTG) to supply electrical power, and a single RTG is used by New
Horizons. To accommodate this constraint, the spacecraft electronics were
designed to operate on less than 200 W. The spacecraft system architecture
provides sufficient redundancy to provide a probability of mission success of
greater than 0.85, even with a mission duration of over 10 years. The
spacecraft is now on its way to Pluto, with an arrival date of 14 July 2015.
Initial inflight tests have verified that the spacecraft will meet the design
requirements.Comment: 33 pages, 13 figures, 4 tables; To appear in a special volume of
Space Science Reviews on the New Horizons missio
A novel model of lethal Hendra virus infection in African green monkeys and the effectiveness of ribavirin treatment
The henipaviruses, Hendra virus (HeV) and Nipah virus (NiV), are emerging zoonotic paramyxoviruses that can cause severe and often lethal neurologic and/or respiratory disease in a wide variety of mammalian hosts, including humans. There are presently no licensed vaccines or treatment options approved for human or veterinarian use. Guinea pigs, hamsters, cats, and ferrets, have been evaluated as animal models of human HeV infection, but studies in nonhuman primates (NHP) have not been reported, and the development and approval of any vaccine or antiviral for human use will likely require efficacy studies in an NHP model. Here, we examined the pathogenesis of HeV in the African green monkey (AGM) following intratracheal inoculation. Exposure of AGMs to HeV produced a uniformly lethal infection, and the observed clinical signs and pathology were highly consistent with HeV-mediated disease seen in humans. Ribavirin has been used to treat patients infected with either HeV or NiV; however, its utility in improving outcome remains, at best, uncertain. We examined the antiviral effect of ribavirin in a cohort of nine AGMs before or after exposure to HeV. Ribavirin treatment delayed disease onset by 1 to 2 days, with no significant benefit for disease progression and outcome. Together our findings introduce a new disease model of acute HeV infection suitable for testing antiviral strategies and also demonstrate that, while ribavirin may have some antiviral activity against the henipaviruses, its use as an effective standalone therapy for HeV infection is questionable. Copyrigh
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