1,915 research outputs found
Program listing for the REEDM (Rocket Exhaust Effluent Diffusion Model) computer program
The program listing for the REEDM Computer Program is provided. A mathematical description of the atmospheric dispersion models, cloud-rise models, and other formulas used in the REEDM model; vehicle and source parameters, other pertinent physical properties of the rocket exhaust cloud and meteorological layering techniques; user's instructions for the REEDM computer program; and worked example problems are contained in NASA CR-3646
User's manual for the REEDM (Rocket Exhaust Effluent Diffusion Model) computer program
The REEDM computer program predicts concentrations, dosages, and depositions downwind from normal and abnormal launches of rocket vehicles at NASA's Kennedy Space Center. The atmospheric dispersion models, cloud-rise models, and other formulas used in the REEDM model are described mathematically Vehicle and source parameters, other pertinent physical properties of the rocket exhaust cloud, and meteorological layering techniques are presented as well as user's instructions for REEDM. Worked example problems are included
Causality and the semantics of provenance
Provenance, or information about the sources, derivation, custody or history
of data, has been studied recently in a number of contexts, including
databases, scientific workflows and the Semantic Web. Many provenance
mechanisms have been developed, motivated by informal notions such as
influence, dependence, explanation and causality. However, there has been
little study of whether these mechanisms formally satisfy appropriate policies
or even how to formalize relevant motivating concepts such as causality. We
contend that mathematical models of these concepts are needed to justify and
compare provenance techniques. In this paper we review a theory of causality
based on structural models that has been developed in artificial intelligence,
and describe work in progress on a causal semantics for provenance graphs.Comment: Workshop submissio
The Case for Enhanced Data Collection of Gun Type
Background: National surveillance systems have differentiated long guns into rifles and shotguns but fail to do so for handgun type. We sought to determine whether specific gun type data could be collected and whether knowledge of specific gun types (rifle, shotgun, pistol, revolver) could be used to distinguish gun homicide victims with respect to important injury parameters such as number of wounds. Methods: Data on gun fatalities over a 5-year period in three communities were abstracted from medical examiner/coroner, police, and crime laboratory records. Results: Gun type was obtained for 92% of 490 guns linked to 405 gun homicides. Handguns were associated with more wounds per gun than long guns (p = 0.001) and more entry wounds per gun than long guns (p = 0.002). Among handguns, pistols were associated with more wounds per gun (p \u3c 0.001) and entry wounds per gun (p = 0.001) than revolvers. These same associations were not found among specific long gun types (i.e., rifles and shotguns). Conclusion: Our findings demonstrate that information about gun type can be obtained and that significant differences exist in wounds per gun between long guns and handguns and between pistols and revolvers. Classification of long guns into rifles and shotguns and handguns into pistols and revolvers should be included in local, regional, and national data collection systems
Super-resolution, Extremal Functions and the Condition Number of Vandermonde Matrices
Super-resolution is a fundamental task in imaging, where the goal is to
extract fine-grained structure from coarse-grained measurements. Here we are
interested in a popular mathematical abstraction of this problem that has been
widely studied in the statistics, signal processing and machine learning
communities. We exactly resolve the threshold at which noisy super-resolution
is possible. In particular, we establish a sharp phase transition for the
relationship between the cutoff frequency () and the separation ().
If , our estimator converges to the true values at an inverse
polynomial rate in terms of the magnitude of the noise. And when no estimator can distinguish between a particular pair of
-separated signals even if the magnitude of the noise is exponentially
small.
Our results involve making novel connections between {\em extremal functions}
and the spectral properties of Vandermonde matrices. We establish a sharp phase
transition for their condition number which in turn allows us to give the first
noise tolerance bounds for the matrix pencil method. Moreover we show that our
methods can be interpreted as giving preconditioners for Vandermonde matrices,
and we use this observation to design faster algorithms for super-resolution.
We believe that these ideas may have other applications in designing faster
algorithms for other basic tasks in signal processing.Comment: 19 page
Myosin-X functions in polarized epithelial cells
Myosin-X, an unconventional myosin that has been studied primarily in fibroblast-like cells, has been shown to have important functions in polarized epithelial cell junction formation, regulation of paracellular permeability, and epithelial morphogenesis.Myosin-X (Myo10) is an unconventional myosin that localizes to the tips of filopodia and has critical functions in filopodia. Although Myo10 has been studied primarily in nonpolarized, fibroblast-like cells, Myo10 is expressed in vivo in many epithelia-rich tissues, such as kidney. In this study, we investigate the localization and functions of Myo10 in polarized epithelial cells, using Madin-Darby canine kidney II cells as a model system. Calcium-switch experiments demonstrate that, during junction assembly, green fluorescent protein–Myo10 localizes to lateral membrane cell–cell contacts and to filopodia-like structures imaged by total internal reflection fluorescence on the basal surface. Knockdown of Myo10 leads to delayed recruitment of E-cadherin and ZO-1 to junctions, as well as a delay in tight junction barrier formation, as indicated by a delay in the development of peak transepithelial electrical resistance (TER). Although Myo10 knockdown cells eventually mature into monolayers with normal TER, these monolayers do exhibit increased paracellular permeability to fluorescent dextrans. Importantly, knockdown of Myo10 leads to mitotic spindle misorientation, and in three-dimensional culture, Myo10 knockdown cysts exhibit defects in lumen formation. Together these results reveal that Myo10 functions in polarized epithelial cells in junction formation, regulation of paracellular permeability, and epithelial morphogenesis
Sustainable Affordable Housing - Submission to Inquiry into First Home Ownership
The Institute welcomes this opportunity to submit comments to the Commissions Inquiry evaluating the affordability and availability of housing for first home buyers. The Institute for Sustainable Futures is a self-funded research and consulting institute of the University of Technology, Sydney. The Institutes mission is to support and create change towards sustainable futures by working with government, industry and the community. Social sustainability, sustainable housing and sustainable urban infrastructure for energy, water and transport are all key parts of this mission.1 This submission seeks to evaluate the affordability and availability of housing for first home buyers within the framework of ecologically sustainable development (ESD). It is in two parts. Part I: Submission provides the framework. Part II: Comments on the Commissions Issues Paper provides more details on this framework under the broad headings used in the Commissions Issues Paper
Effective Trauma Center Partnerships to Address Firearm Injury: A New Paradigm
Background: Firearm violence is the second leading cause of injury-related death. This study examined the use of local trauma centers as lead organizations in their communities to address firearm injury. Methods: Three trauma centers in cities with populations less than 100,000 were linked with a university-based firearm injury research center. A trauma surgeon director and coordinator partnered with communities, recruited and directed advisory boards, established a local firearm injury surveillance system, and informed communities using community-specific profiles. Primary process and outcome measures included completeness of data, development of community-specific profiles, number of data-driven consumer media pieces, number of meetings to inform policy makers, and an analysis of problems encountered. Results: Local trauma centers in smaller communities implemented a firearm injury surveillance system, produced community-specific injury profiles, and engaged community leaders and policy makers to address firearm injury. Community-specific profiles demonstrated consistent firearm suicide rates (6.58–6.82 per 100,000) but variation in firearm homicide rates (1.08–12.5 per 100,000) across sites. There were 63 data-driven media pieces and 18 forums to inform community leaders and policy makers. Completeness of data elements ranged from 57.1% to 100%. Problems experienced were disconnected data sources, multiple data owners, potential for political fallout, limited trauma center data, skills sets of medical professionals, and sustainability. Conclusion: Trauma centers, when provided resources and support, with the model described, can function as lead organizations in partnering with the community to acquire and use community-specific data for local firearm injury prevention
A dependent nominal type theory
Nominal abstract syntax is an approach to representing names and binding
pioneered by Gabbay and Pitts. So far nominal techniques have mostly been
studied using classical logic or model theory, not type theory. Nominal
extensions to simple, dependent and ML-like polymorphic languages have been
studied, but decidability and normalization results have only been established
for simple nominal type theories. We present a LF-style dependent type theory
extended with name-abstraction types, prove soundness and decidability of
beta-eta-equivalence checking, discuss adequacy and canonical forms via an
example, and discuss extensions such as dependently-typed recursion and
induction principles
Alternative Markers of Performance in Simulation: Where We Are and Where We Need To Go
This article on alternative markers of performance in simulation is the product of a session held during the 2017 Academic Emergency Medicine Consensus Conference â Catalyzing System Change Through Health Care Simulation: Systems, Competency, and Outcomes.â There is a dearth of research on the use of performance markers other than checklists, holistic ratings, and behaviorally anchored rating scales in the simulation environment. Through literature review, group discussion, and consultation with experts prior to the conference, the working group defined five topics for discussion: 1) establishing a working definition for alternative markers of performance, 2) defining goals for using alternative performance markers, 3) implications for measurement when using alternative markers, identifying practical concerns related to the use of alternative performance markers, and 5) identifying potential for alternative markers of performance to validate simulation scenarios. Five research propositions also emerged and are summarized.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142535/1/acem13321_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/142535/2/acem13321.pd
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