4,506 research outputs found

    Some Aspects of Non-Darcy Behavior of Gas Flow In Wood

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    A study was undertaken to determine if the Klinkenberg equation for gas flow through porous media could be applied to a wide variety of wood species. When the results proved negative, a second study was initiated to determine if the cause of the nonconformities could be traced to turbulence. The combined experiments indicated that neither molecular slippage, as described by the Klinkenberg equation, nor turbulence can adequately explain the reduction in apparent permeability with increasing mean pressure

    Apollo experience report: Development of guidance targeting techniques for the command module and launch vehicle

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    The development of the guidance targeting techniques for the Apollo command module and launch vehicle is discussed for four types of maneuvers: (1) translunar injection, (2) translunar midcourse, (3) lunar orbit insertion, and (4) return to earth. The development of real-time targeting programs for these maneuvers and the targeting procedures represented are discussed. The material is intended to convey historically the development of the targeting techniques required to meet the defined target objectives and to illustrate the solutions to problems encountered during that development

    Astronomy in the Cloud: Using MapReduce for Image Coaddition

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    In the coming decade, astronomical surveys of the sky will generate tens of terabytes of images and detect hundreds of millions of sources every night. The study of these sources will involve computation challenges such as anomaly detection and classification, and moving object tracking. Since such studies benefit from the highest quality data, methods such as image coaddition (stacking) will be a critical preprocessing step prior to scientific investigation. With a requirement that these images be analyzed on a nightly basis to identify moving sources or transient objects, these data streams present many computational challenges. Given the quantity of data involved, the computational load of these problems can only be addressed by distributing the workload over a large number of nodes. However, the high data throughput demanded by these applications may present scalability challenges for certain storage architectures. One scalable data-processing method that has emerged in recent years is MapReduce, and in this paper we focus on its popular open-source implementation called Hadoop. In the Hadoop framework, the data is partitioned among storage attached directly to worker nodes, and the processing workload is scheduled in parallel on the nodes that contain the required input data. A further motivation for using Hadoop is that it allows us to exploit cloud computing resources, e.g., Amazon's EC2. We report on our experience implementing a scalable image-processing pipeline for the SDSS imaging database using Hadoop. This multi-terabyte imaging dataset provides a good testbed for algorithm development since its scope and structure approximate future surveys. First, we describe MapReduce and how we adapted image coaddition to the MapReduce framework. Then we describe a number of optimizations to our basic approach and report experimental results comparing their performance.Comment: 31 pages, 11 figures, 2 table

    The Art of Data Science

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    To flourish in the new data-intensive environment of 21st century science, we need to evolve new skills. These can be expressed in terms of the systemized framework that formed the basis of mediaeval education - the trivium (logic, grammar, and rhetoric) and quadrivium (arithmetic, geometry, music, and astronomy). However, rather than focusing on number, data is the new keystone. We need to understand what rules it obeys, how it is symbolized and communicated and what its relationship to physical space and time is. In this paper, we will review this understanding in terms of the technologies and processes that it requires. We contend that, at least, an appreciation of all these aspects is crucial to enable us to extract scientific information and knowledge from the data sets which threaten to engulf and overwhelm us.Comment: 12 pages, invited talk at Astrostatistics and Data Mining in Large Astronomical Databases workshop, La Palma, Spain, 30 May - 3 June 2011, to appear in Springer Series on Astrostatistic

    EMSL Quarterly Highlights Report Second Quarter, Fiscal Year 2010 (January 1, 2010 through March 31, 2010)

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    The Environmental Molecular Sciences Laboratory (EMSL) is a U.S. Department of Energy (DOE) national scientific user facility located at Pacific Northwest National Laboratory (PNNL) in Richland, Washington. EMSL is operated by PNNL for the DOE-Office of Biological and Environmental Research. At one location, EMSL offers a comprehensive array of leading-edge resources and expertise. Access to the instrumentation and expertise is obtained on a peer-reviewed proposal basis. Staff members work with researchers to expedite access to these capabilities. The "EMSL Quarterly Highlights Report" documents current research and activities of EMSL staff and users

    The influence of a Juvenile\u27s Abuse History on Support for Sex Offender Registration

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    We investigated whether and how a juvenile’s history of experiencing sexual abuse affects public perceptions of juvenile sex offenders in a series of 5 studies. When asked about juvenile sex offenders in an abstract manner (Studies 1 and 2), the more participants (community members and undergraduates) believed that a history of being sexually abused as a child causes later sexually abusive behavior, the less likely they were to support sex offender registration for juveniles. Yet when participants considered specific sexual offenses, a juvenile’s history of sexual abuse was not considered to be a mitigating factor. This was true when participants considered a severe sexual offense (forced rape; Study 3 and Study 4) and a case involving less severe sexual offenses (i.e., statutory rape), when a juvenile’s history of sexual abuse backfired and was used as an aggravating factor, increasing support for registering the offender (Study 3 and Study 5). Theoretical and practical implications of these results are discussed

    Improving Practice Accessibility Through MyChart Utilization

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    Aims for Improvement Increase patient portal MyChart activation for a cohort of approximately 2,000 patients at JFMA by 1% from February to April 2021. Demonstrate evidence of utilization including appointment scheduling, results review, and communication with providers through MyChart after activation

    A Multimetric Assessment of Stream Condition in the Northern Lakes and Forests Ecoregion Using Spatially Explicit Statistical Modeling and Regional Normalization

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    We sampled fish communities, water temperature, water chemistry, physical habitat, and catchment characteristics for 94 stream sites selected randomly throughout the Northern Lakes and Forests ecoregion and used those data to explicitly model reference conditions and assess ecological stream condition at each site via a regional normalization framework. The streams we sampled were first order through fourth order, and the catchments ranged from 0.9 to 458 km2. We developed multiple linear regression (MLR) models that predicted fish community metrics, water chemistry characteristics, and local physical habitat from catchment characteristics; we used these models to compare existing conditions with the conditions that would be expected based on the regression models. Our results indicated that the fish communities were relatively unimpaired because the catchment variables associated with human‐induced land use change were important in only 1 of the 10 fish metric models. Agricultural land use was a significant variable in the MLR equation for species of Lepomis (sunfish). Agricultural land use and urban land use were both significant variables in all of the MLR models predicting water chemistry variables; urban land use was a significant variable in the MLR model predicting the percent coverage of all instream cover types. Regional normalization indicated that none of the sites were impaired based on fish community attributes. However, our analysis based on water chemistry metrics indicated that 22– 35% of the sites were impaired and that, based on physical habitat, 6–14% of the sites were impaired. A comparison with other published studies of the ecoregion suggested that the regional normalization process correctly characterized stream condition.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141590/1/tafs0697.pd

    Annual sea-air CO2fluxes in the Bering Sea: insights from new autumn and winter observations of a seasonally ice-covered continental shelf

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    High-resolution data collected from several programs have greatly increased the spatiotemporal resolution of pCO2(sw) data in the Bering Sea, and provided the first autumn and winter observations. Using data from 2008 to 2012, monthly climatologies of sea-air CO2 fluxes for the Bering Sea shelf area from April to December were calculated, and contributions of physical and biological processes to observed monthly sea-air pCO2 gradients (?pCO2) were investigated. Net efflux of CO2 was observed during November, December, and April, despite the impact of sea surface cooling on ?pCO2. Although the Bering Sea was believed to be a moderate to strong atmospheric CO2 sink, we found that autumn and winter CO2 effluxes balanced 65% of spring and summer CO2 uptake. Ice cover reduced sea-air CO2 fluxes in December, April, and May. Our estimate for ice-cover corrected fluxes suggests the mechanical inhibition of CO2 flux by sea-ice cover has only a small impact on the annual scale (<2%). An important data gap still exists for January to March, the period of peak ice cover and the highest expected retardation of the fluxes. By interpolating between December and April using assumptions of the described autumn and winter conditions, we estimate the Bering Sea shelf area is an annual CO2 sink of ?6.8 Tg C yr?1. With changing climate, we expect warming sea surface temperatures, reduced ice cover, and greater wind speeds with enhanced gas exchange to decrease the size of this CO2 sink by augmenting conditions favorable for greater wintertime outgassing

    Identifying Areas with Disproportionate Local Health Department Services Relative to Opioid Overdose, HIV and Hepatitis C Diagnosis Rates: A Study of Rural Illinois

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    Background: U.S. rural populations have been disproportionately affected by the syndemic of opioid-use disorder (OUD) and the associated increase in overdoses and risk of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) transmission. Local health departments (LHDs) can play a critical role in the response to this syndemic. We utilized two geospatial approaches to identify areas of discordance between LHD service availability and disease burden to inform service prioritization in rural settings.Methods: We surveyed rural Illinois LHDs to assess their OUD-related services, and calculated county-level opioid overdose, HIV, and hepatitis C diagnosis rates. Bivariate choropleth maps were created to display LHD service provision relative to disease burden in rural Illinois counties. Results: Most rural LHDs provided limited OUD-related services, although many LHDs provided HIV and HCV testing. Bivariate mapping showed rural counties with limited OUD treatment and HIV services and with corresponding higher outcome/disease rates to be dispersed throughout Illinois. Additionally, rural counties with limited LHD-offered hepatitis C services and high hepatitis C diagnosis rates were geographically concentrated in southern Illinois. Conclusions: Bivariate mapping can enable geographic targeting of resources to address the opioid crisis and related infectious disease by identifying areas with low LHD services relative to high disease burden
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