Browsing by Subject "Sampling"

Now showing 1 - 4 of 4
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    Analysis of Mercury Concentrations in Indiana Soil to Evaluate Patterns of Long-Term Atmospheric Mercury Deposition
    (2013-01-09) Crewe, Julie R.; Filippelli, Gabriel M.; Babbar-Sebens, Meghna; Risch, Martin R.
    Mercury (Hg) has proven to be a risk to the public, mainly through the consumption of fish. Because of this, many fish consumption advisories have been issued in Indiana. Although much is known about the global cycle of mercury, little is known about how local and regional emission sources of mercury impact local and regional mercury cycling. This study’s objective was to determine the scope of mercury concentration in central Indiana by using a broad grid of soil mercury measurements. Sampling was designed to capture the net retained mercury content in soils, and to determine whether spatial patterns in exist in soil mercury contents that could be related to emission sources of mercury and post-emission transport patterns from wind. Results from this study revealed significant differences in mercury concentrations for soils in central Indiana. The core of the study area, concentrated in the urban area of Indianapolis, exhibited soil mercury contents that were 20 times higher than values in the outskirts of the study area. The spatial pattern resembled a bulls-eye shape centered on Indianapolis, and with comparison to the reported Hg emission from local sources, including a coal-fired power plant, indicates a strong regional deposition signal linked to those emission sources but marked by wind-driven transport to the northeast. This effect of local emission sources resulting in local deposition indicates that limiting mercury emissions will have a net beneficial impact on local environmental quality and human health.
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    Antecedents and outcomes of work-linked couple incivility
    (2014) Jones, Morgan Dakota; Sliter, Michael; Devine, Denis John; Williams, Jane R.
    Workplace incivility has been shown to have negative organizational and individual effects on people who experience this low-intensity deviant behavior. Research has recently begun to look at incivility as a form of modern discrimination that may be used to target out-groups within organizations, where out-groups are broadly defined. The first goal of the current study was to examine the impact of incivility on work-linked couples. Second, the present study sought to determine the effect that experiences of WLC incivility had on individual and organizational outcomes: burnout, job satisfaction, and turnover intentions. Finally, although the outcomes of incivility have been well-established, the antecedents of this phenomenon have been examined considerably less. Therefore, the present study sought to examine and explain the relationship between a climate for formality, gender, and WLC incivility. To accomplish these goals a snowball sampling method was used to recruit a total of 86 participants for an online survey. Hierarchal regression and bootstrapping mediation were used to analyze the data. Results showed that WLC incivility was predictive of burnout, job dissatisfaction, and turnover intentions. Furthermore, both burnout and job satisfaction were shown to mediate the relationship between WLC incivility and turnover intentions. The theoretical and practical implications of these results are discussed as well as potential areas for future research.
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    Managing work flow in high enrolling trials: The development and implementation of a sampling strategy in the PREPARE trial
    (Elsevier, 2021-01-23) Pogorzelski, David; Nguyen, Uyen; McKay, Paula; Thabane, Lehana; Camara, Megan; Ramsey, Lolita; Seymour, Rachel; Goodman, J. Brett; McGee, Sheketha; Fraifogl, Joanne; Hudgins, Andrea; Tanner, Stephanie L.; Bhandari, Mohit; Slobogean, Gerard P.; Sprague, Sheila; Orthopaedic Surgery, School of Medicine
    Introduction: Pragmatic trials in comparative effectiveness research assess the effects of different treatment, therapeutic, or healthcare options in clinical practice. They are characterized by broad eligibility criteria and large sample sizes, which can lead to an unmanageable number of participants, increasing the risk of bias and affecting the integrity of the trial. We describe the development of a sampling strategy tool and its use in the PREPARE trial to circumvent the challenge of unmanageable work flow. Methods: Given the broad eligibility criteria and high fracture volume at participating clinical sites in the PREPARE trial, a pragmatic sampling strategy was needed. Using data from PREPARE, descriptive statistics were used to describe the use of the sampling strategy across clinical sites. A Chi-square test was performed to explore whether use of the sampling strategy was associated with a reduction in the number of missed eligible patients. Results: 7 of 20 clinical sites (35%) elected to adopt a sampling strategy. There were 1539 patients excluded due to the use of the sampling strategy, which represents 30% of all excluded patients and 20% of all patients screened for participation. Use of the sampling strategy was associated with lower odds of missed eligible patients (297/4545 (6.5%) versus 341/3200 (10.7%) p < 0.001). Conclusions: Implementing a sampling strategy in the PREPARE trial has helped to limit the number of missed eligible patients. This sampling strategy represents a simple, easy to use tool for managing work flow at clinical sites and maintaining the integrity of a large trial.
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    On approximating initial data in some linear evolutionary equations involving fraction Laplacian
    (Western Libraries at The University of Western Ontario, 2022) Karki, Ramesh; Mathematical Sciences, School of Science
    We study an inverse problem of recovering the intial datum in a one-dimensional linear equation with Dirichlet boundary conditions when finitely many values (samples) of the solution at a suitably fixed space loaction and suitably chosen finitely many later time instances are known. More specifically, we do this. We consider a one-dimentional linear evolutionary equation invliing a Dirichlet fractional Laplacian and the unknown intial datum f that is assumed to be in a suitable subset of a Sovolev space. Then we investigate how to construct a sequence of future times and choose n so that from n samples taken at a suitably fixed space location and the first n terms of the time sequence we can constrcut an approximation to f with the desired accuracy.