2,896 research outputs found

    Exploring Social Media Sentiment Analysis in Relation to Common Stock

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    Many institutions, investors, and researchers have sought to gain insights into consumer attitudes and behaviors by leveraging social media. However, trading strategies utilizing social sentiment have been observed to often provide returns roughly equivalent to or less than those of standard market indexes. This observation raises several questions: does the efficacy of social sentiment analysis vary from firm to firm? Are price or volume directly correlated with social sentiment? Does social sentiment display any predictive ability? The following analysis attempted to answer these questions by comparing one week’s worth of data from Twitter users to price and volume data from six publicly traded companies. Although more data is needed to validate this analysis’ findings, there was evidence to suggest that social sentiment’s efficacy varies significantly between firms, changes in prices and volume do not seem to be correlated to changes in social sentiment, and there does appear to be some patterns that could help predict trend reversals in price

    Exploring Social Media Sentiment Analysis in Relation to Common Stock

    Get PDF
    Many institutions, investors, and researchers have sought to gain insights into consumer attitudes and behaviors by leveraging social media. However, trading strategies utilizing social sentiment have been observed to often provide returns roughly equivalent to or less than those of standard market indexes. This observation raises several questions: does the efficacy of social sentiment analysis vary from firm to firm? Are price or volume directly correlated with social sentiment? Does social sentiment display any predictive ability? The following analysis attempted to answer these questions by comparing one week’s worth of data from Twitter users to price and volume data from six publicly traded companies. Although more data is needed to validate this analysis’ findings, there was evidence to suggest that social sentiment’s efficacy varies significantly between firms, changes in prices and volume do not seem to be correlated to changes in social sentiment, and there does appear to be some patterns that could help predict trend reversals in price

    Design Optimization for Manufacturing for Farrowing System

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    Designing a farrowing system; Keeping it manufacturable; Keeping it functional; Keeping it within cost parameters

    2009 Alaska Health Workforce Vacancy Study

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    Alaska continues to experience health professional shortages. The state has long had a deficient “supply side” characterized by insufficient numbers of key health workers whose recruitment, retention, and training have been impeded by Alaska’s remoteness, harsh climate, rural isolation, low population density, and scarce training resources. Alaska is the only state without a pharmacy school and lacks its own dental and physical therapy schools as well. Health professional shortages can be decreased through the start of new training programs, the expansion of existing programs, and the improvement of the effectiveness of recruitment and retention efforts. However, strategic planning and the execution of such programs require valid and accurate data. To this end, stakeholders such as the Alaska Mental Health Trust Authority (AMHTA) and Alaskan's For Access to Health Care (ACCESS), along with schools and departments within the University of Alaska Anchorage (UAA), funded the Alaska Center for Rural Health-Alaska’s AHEC (ACRH) and the Institute of Social and Economic Research (ISER) to conduct a comprehensive health workforce study during winter and spring of 2009. This report highlights employers’ needs for employees to fill budgeted positions. This is different from a needs assessment that would take into account population demographics and disease incidence and prevalence. This health workforce study is an assessment of health manpower shortage based on budgeted staff positions and their vacancies in organizations throughout the state. Respondents included part-time positions, which resulted in our counting full-time equivalent (FTE) rather than individuals (“bodies”). In situations where a position was divided among more than one occupation (e.g., Dental Assistant and Billing Clerk), we asked the respondent to count the position under which they considered the position’s “primary occupation.” This was a point-in-time cross-sectional study. Recently filled vacancies or imminent vacancies were not counted. Positions filled by relief/temporary/locum/contract health workers were counted as vacancies only if these workers were temporarily filling a currently vacant, budgeted position. Due to budget and time constraints, we were not able to conduct a trend analysis that is a comparison of this study’s findings and the prior 2007 study. The key questions this study sought to answer were (1) How many budgeted positions, either full- or part-time, existed in organizations providing health services in Alaska? (2) How many of these budgeted positions were currently vacant? (3) What was the vacancy rate? (4) How many of the organizations that employ these occupations hired new graduates of training programs? (5) How many of the currently vacant budgeted positions (#2) could be filled by new graduates of training programs? (6) What were the mean and maximum length of time, expressed in months, that the vacancies have existed? (7) What were the principal, underlying causes of vacancies? The study was designed in consultation with an advisory group that included AMHTA, ACCESS, and UAA. The study targeted 93 health occupations. The unit of analysis was the employment site by organization type, which allowed for the allocation of positions and vacancies by geographic region. For each employer, we identified the staff person most knowledgeable about hiring and vacancies. In large organizations this meant that one employer might provide information about multiple sites and organization types; smaller employers were responsible for only a single site.Alaska Mental Health Trust Authority. Alaskan's for Access to Health Care. University of Alaska Fairbanks, Tanana Valley campus Telemedicine program. University of Alaska Anchorage, Community and Technical College. University of Alaska Anchorage, School of Nursing.Acknowledgements / Executive Summary / Table of Contents / Problem and Rationale / Methodology / Limitations of Study / Findings / Appendix A. List of Health Occupations / Appendix B. Health Workforce Surveys / Appendix C. Cover Letter Accompanying Survey Forms / Appendix D. Confidence Intervals for Positions, Vacancies, Number of Vacancies Filled with New Graduates, and Length of Longest Vacancy in Months / Appendix E. Tables of Samples and Estimates of Positions, Vacancies, Vacancy Rates, Number of Vacancies Filled with New Graduates, Mean and Maximum Length of Longest Vacancy in Months / Appendix F. Tables of Occupations Sorted By Estimates of Positions, Vacancies, Vacancy Rates, Number of Vacancies Filled with New Graduates, Mean and Maximum Length of Longest Vacancy in Month

    Determination of an Interaction Network between an Extracellular Bacterial Pathogen and the Human Host

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    A major gap in understanding infectious diseases is the lack of information about molecular interaction networks between pathogens and the human host. Haemophilus ducreyi causes the genital ulcer disease chancroid in adults and is a leading cause of cutaneous ulcers in children in the tropics. We developed a model in which human volunteers are infected on the upper arm with H. ducreyi until they develop pustules. To define the H. ducreyi and human interactome, we determined bacterial and host transcriptomic and host metabolomic changes in pustules. We found that in vivo H. ducreyi transcripts were distinct from those in the inocula, as were host transcripts in pustule and wounded control sites. Many of the upregulated H. ducreyi genes were found to be involved in ascorbic acid and anaerobic metabolism and inorganic ion/nutrient transport. The top 20 significantly expressed human pathways showed that all were involved in immune responses. We generated a bipartite network for interactions between host and bacterial gene transcription; multiple positively correlated networks contained H. ducreyi genes involved in anaerobic metabolism and host genes involved with the immune response. Metabolomic studies showed that pustule and wounded samples had different metabolite compositions; the top ion pathway involved ascorbate and aldarate metabolism, which correlated with the H. ducreyi transcriptional response and upregulation of host genes involved in ascorbic acid recycling. These data show that an interactome exists between H. ducreyi and the human host and suggest that H. ducreyi exploits the metabolic niche created by the host immune response.IMPORTANCE Dual RNA sequencing (RNA-seq) offers the promise of determining an interactome at a transcriptional level between a bacterium and the host but has yet to be done on any bacterial infection in human tissue. We performed dual RNA-seq and metabolomics analyses on wounded and infected sites following experimental infection of the arm with H. ducreyi Our results suggest that H. ducreyi survives in an abscess by utilizing l-ascorbate as an alternative carbon source, possibly taking advantage of host ascorbic acid recycling, and that H. ducreyi also adapts by upregulating genes involved in anaerobic metabolism and inorganic ion and nutrient transport. To our knowledge, this is the first description of an interaction network between a bacterium and the human host at a site of infection

    Evapotranspiration Rates of Riparian Forests, Platte River, Nebraska, 2002–06

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    Evapotranspiration (ET) in riparian areas is a poorly understood component of the regional water balance in the Platte River Basin, where competing demands have resulted in water shortages in the ground-water/surface-water system. From April 2002 through March 2006, the U.S. Geological Survey, Nebraska Platte River Cooperative Hydrology Study Group, and Central Platte Natural Resources District conducted a micrometeorological study of water and energy balances at two sites in central Nebraska near Odessa and Gothenburg to improve understanding of ET rates and factors affecting them in Platte River riparian forests. A secondary objective of the study was to constrain estimates of ground-water use by riparian vegetation to satisfy ET consumptive demands, a useful input to regional ground-water flow models. Both study sites are located on large islands within the Platte River characterized by a cottonwood-dominated forest canopy on primarily sandy alluvium. Although both sites are typical of riparian forests along the Platte River in Nebraska, the Odessa understory is dominated by deciduous shrubs, whereas the Gothenburg understory is dominated by eastern redcedars. Additionally, seasonal ground-water levels fluctuated more at Odessa than at Gothenburg. The study period of April 2002 through March 2006 encompassed precipitation conditions ranging from dry to wet. This study characterized the components of the water balance in the riparian zone of each site. ET was evaluated from eddy-covariance sensors installed on towers above the forest canopy at a height of 26.1 meters. Precipitation was measured both above and below the forest canopy. A series of sensors measured soil-moisture availability within the unsaturated zone in two different vertical profiles at each site. Changes in ground-water altitude were evaluated from piezometers. The areal footprint represented in the water balance extended up to 800 meters from each tower. During the study, ET was less variable than precipitation. Annual ET fluctuated about 7 percent from the 4-year mean, ranging from about 514 to 586 millimeters per year (551 on average) at the Odessa site and 535 to 616 millimeters per year (575 on average) at the Gothenburg site. Conversely, annual precipitation fluctuated by about 35 percent from the 4-year mean, ranging from 429 to 844 millimeters per year at Odessa and 359 to 791 millimeters per year at Gothenburg. Of this precipitation, 14 to 15 percent was intercepted by the forest canopy before it could infiltrate into the soil. For the 4-year period, annual ground-water recharge from the riparian measurement zone averaged 76 and 13 millimeters at Odessa and Gothenburg, respectively, to satisfy the water balance at each site. This indicates that, from an annual perspective, ground-water reductions caused by ET may be minimal. This effect varied somewhat and primarily was affected by fluctuations in precipitation. Ground-water discharge occurred during the driest study year (2002), whereas ground-water recharge occurred from 2003 to 2005. These results do not exclude ground water as an important source of water to riparian vegetation—especially to phreatophytes that have the capability of directly using water from the saturated zone—during periods of high ET in the summer, particularly during periods of lower than normal precipitation. However, the calculations indicate that, on an annual (or longer) net-flux basis, ground-water use by riparian forests is likely to be balanced by periods of recharge from excess precipitation at other times of the year. In contrast to more arid settings, where scientific literature indicates that ground water may supply a large fraction of the water used for ET by riparian vegetation, precipitation along the Platte River of Nebraska was great enough—and generally greater than ET—that most or all of the annual ET demand was satisfied by available precipitation. Crop coefficients developed for 15-day and monthly periods from the measured data predicted ET within 3.5 percent of actual annual ET; however, daily ET was underpredicted on days of increased ET and overpredicted on days of low ET. These crop coefficients can be used to extrapolate riparian-forest ET along the Platte River in conjunction with atmospheric data from other climate stations in central Nebraska. Regression models of simple and multiple-linear relations between explanatory variables and ET indicated that the relation of ET to environmental factors was different on days with precipitation than on dry days. At Odessa, ET was affected by vapor-pressure deficit, solar radiation, leaf-area index, and depth to water regardless of precipitation conditions, but was also affected by air temperature on days without precipitation, suggesting energy limitations on ET on days without precipitation. At Gothenburg, ET was always a function of vapor-pressure deficit, solar radiation, and leaf-area index, but, as with Odessa, air temperature also became important on days without precipitation. Despite depths to ground water of less than 2 meters and phreatophytic vegetation, measured ET was substantially less than potential ET (based on the modified Penman method), consistent with plant-stomatal regulation of ET in response to environmental and meteorological factors. Although annual ET rates generally were similar, the two sites exhibited different intraannual soil-moisture regimes that had a corresponding effect on ET and vegetation vigor. Smaller seasonal declines in ground-water levels and a lack of understory shrubs at the Gothenburg site as compared to the Odessa site may explain why Gothenburg ET was comparatively greater later in the summer and was not dependent on depth to water (as identified by the multiple-linear regression model). These differences also may explain why, during years of increased precipitation, ET rates increased at Odessa but not at Gothenburg

    Evapotranspiration Rates of Riparian Forests, Platte River, Nebraska, 2002–06

    Get PDF
    Evapotranspiration (ET) in riparian areas is a poorly understood component of the regional water balance in the Platte River Basin, where competing demands have resulted in water shortages in the ground-water/surface-water system. From April 2002 through March 2006, the U.S. Geological Survey, Nebraska Platte River Cooperative Hydrology Study Group, and Central Platte Natural Resources District conducted a micrometeorological study of water and energy balances at two sites in central Nebraska near Odessa and Gothenburg to improve understanding of ET rates and factors affecting them in Platte River riparian forests. A secondary objective of the study was to constrain estimates of ground-water use by riparian vegetation to satisfy ET consumptive demands, a useful input to regional ground-water flow models. Both study sites are located on large islands within the Platte River characterized by a cottonwood-dominated forest canopy on primarily sandy alluvium. Although both sites are typical of riparian forests along the Platte River in Nebraska, the Odessa understory is dominated by deciduous shrubs, whereas the Gothenburg understory is dominated by eastern redcedars. Additionally, seasonal ground-water levels fluctuated more at Odessa than at Gothenburg. The study period of April 2002 through March 2006 encompassed precipitation conditions ranging from dry to wet. This study characterized the components of the water balance in the riparian zone of each site. ET was evaluated from eddy-covariance sensors installed on towers above the forest canopy at a height of 26.1 meters. Precipitation was measured both above and below the forest canopy. A series of sensors measured soil-moisture availability within the unsaturated zone in two different vertical profiles at each site. Changes in ground-water altitude were evaluated from piezometers. The areal footprint represented in the water balance extended up to 800 meters from each tower. During the study, ET was less variable than precipitation. Annual ET fluctuated about 7 percent from the 4-year mean, ranging from about 514 to 586 millimeters per year (551 on average) at the Odessa site and 535 to 616 millimeters per year (575 on average) at the Gothenburg site. Conversely, annual precipitation fluctuated by about 35 percent from the 4-year mean, ranging from 429 to 844 millimeters per year at Odessa and 359 to 791 millimeters per year at Gothenburg. Of this precipitation, 14 to 15 percent was intercepted by the forest canopy before it could infiltrate into the soil. For the 4-year period, annual ground-water recharge from the riparian measurement zone averaged 76 and 13 millimeters at Odessa and Gothenburg, respectively, to satisfy the water balance at each site. This indicates that, from an annual perspective, ground-water reductions caused by ET may be minimal. This effect varied somewhat and primarily was affected by fluctuations in precipitation. Ground-water discharge occurred during the driest study year (2002), whereas ground-water recharge occurred from 2003 to 2005. These results do not exclude ground water as an important source of water to riparian vegetation—especially to phreatophytes that have the capability of directly using water from the saturated zone—during periods of high ET in the summer, particularly during periods of lower than normal precipitation. However, the calculations indicate that, on an annual (or longer) net-flux basis, ground-water use by riparian forests is likely to be balanced by periods of recharge from excess precipitation at other times of the year. In contrast to more arid settings, where scientific literature indicates that ground water may supply a large fraction of the water used for ET by riparian vegetation, precipitation along the Platte River of Nebraska was great enough—and generally greater than ET—that most or all of the annual ET demand was satisfied by available precipitation. Crop coefficients developed for 15-day and monthly periods from the measured data predicted ET within 3.5 percent of actual annual ET; however, daily ET was underpredicted on days of increased ET and overpredicted on days of low ET. These crop coefficients can be used to extrapolate riparian-forest ET along the Platte River in conjunction with atmospheric data from other climate stations in central Nebraska. Regression models of simple and multiple-linear relations between explanatory variables and ET indicated that the relation of ET to environmental factors was different on days with precipitation than on dry days. At Odessa, ET was affected by vapor-pressure deficit, solar radiation, leaf-area index, and depth to water regardless of precipitation conditions, but was also affected by air temperature on days without precipitation, suggesting energy limitations on ET on days without precipitation. At Gothenburg, ET was always a function of vapor-pressure deficit, solar radiation, and leaf-area index, but, as with Odessa, air temperature also became important on days without precipitation. Despite depths to ground water of less than 2 meters and phreatophytic vegetation, measured ET was substantially less than potential ET (based on the modified Penman method), consistent with plant-stomatal regulation of ET in response to environmental and meteorological factors. Although annual ET rates generally were similar, the two sites exhibited different intraannual soil-moisture regimes that had a corresponding effect on ET and vegetation vigor. Smaller seasonal declines in ground-water levels and a lack of understory shrubs at the Gothenburg site as compared to the Odessa site may explain why Gothenburg ET was comparatively greater later in the summer and was not dependent on depth to water (as identified by the multiple-linear regression model). These differences also may explain why, during years of increased precipitation, ET rates increased at Odessa but not at Gothenburg

    Data-driven methods for diffusivity prediction in nuclear fuels

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    The growth rate of structural defects in nuclear fuels under irradiation is intrinsically related to the diffusion rates of the defects in the fuel lattice. The generation and growth of atomistic structural defects can significantly alter the performance characteristics of the fuel. This alteration of functionality must be accurately captured to qualify a nuclear fuel for use in reactors. Predicting the diffusion coefficients of defects and how they impact macroscale properties such as swelling, gas release, and creep is therefore of significant importance in both the design of new nuclear fuels and the assessment of current fuel types. In this article, we apply data-driven methods focusing on machine learning (ML) to determine various diffusion properties of two nuclear fuels, uranium oxide and uranium nitride. We show that using ML can increase, often significantly, the accuracy of predicting diffusivity in nuclear fuels in comparison to current analytical models. We also illustrate how ML can be used to quickly develop fuel models with parameter dependencies that are more complex and robust than what is currently available in the literature. These results suggest there is potential for ML to accelerate the design, qualification, and implementation of nuclear fuels
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