594 research outputs found

    A model for estimating the TMDL-related benefits of oyster reef restoration : Harris Creek, Maryland, USA

    Get PDF
    A user-friendly, web-accessible model has been developed that allows restoration practitioners and resource managers to easily estimate the TMDL-related benefits of oyster reef restoration per unit area, run restoration scenarios in Harris Creek, MD to optimize restoration planning and implementation, and calculate the benefits of the chosen plan. The model is rooted in scientifically defensible data and is readily transferable to systems throughout the Chesapeake Bay and Eastern Shore. The model operates in five vertically well-mixed boxes along the main axis of the creek. Exchanges among creeks are computed using a tidal prism approach and were compared to exchanges provided from a high resolution 3D hydrodynamic model. Watershed inputs for the model were obtained for the Harris Creek sub-watershed from the Phase V Chesapeake Bay Program Watershed Model. The base model simulates daily concentrations over an annual cycle of chlorophyll-a, dissolved inorganic nitrogen (N) and phosphorus (P), dissolved oxygen, total suspended solids, the biomass of benthic microalgae, and the water column and sediment pools of labile organic carbon (C) and associated N and P. Water quality data for model forcing and calibration were obtained from the Chesapeake Bay Program, the Choptank Riverkeeper, the University of Maryland Center for Environmental Science, and the Maryland Department of Natural Resources. An oyster sub-model has been coupled to this base model and computes the volume of water filtered, removal of phytoplankton, suspended solids, and associated nutrients via filtration, recycling of nutrients and consumption of oxygen by oyster respiration, production of feces, N and P accumulation in oyster tissues and shell, oyster-enhanced denitrification, and N and P burial associated with restored reefs. The completed model is served online and operates through a web browser, enabling users to conduct scenario analysis by entering box-specific values for acres restored, restored oyster density, and restored oyster size, as well as the economic value of associated N and P removal

    Quantitative trait locus-specific genotype × alcoholism interaction on linkage for evoked electroencephalogram oscillations

    Get PDF
    We explored the evidence for a quantitative trait locus (QTL)-specific genotype × alcoholism interaction for an evoked electroencephalogram theta band oscillation (ERP) phenotype on a region of chromosome 7 in participants of the US Collaborative Study on the Genetics of Alcoholism. Among 901 participants with both genotype and phenotype data available, we performed variance component linkage analysis (SOLAR version 2.1.2) in the full sample and stratified by DSM-III-R and Feighner-definite alcoholism categories. The heritability of the ERP phenotype after adjusting for age and sex effects in the combined sample and in the alcoholism classification sub-groups ranged from 40% to 66%. Linkage on chromosome 7 was identified at 158 cM (LOD = 3.8) in the full sample and at 108 in the non-alcoholic subgroup (LOD = 3.1). Further, we detected QTL-specific genotype × alcoholism interaction at these loci. This work demonstrates the importance of considering the complexity of common complex traits in our search for genes that predispose to alcoholism

    Metabolic influences of fiber size in aerobic and anaerobic muscles of the blue crab, Callinectes sapidus

    Get PDF
    Diameters of some white muscle fibers in the adult blue crab, Callinectes sapidus, exceed 500 µm whereas juvenile white fibers are 200 g were examined with transmission electron microscopy to determine the density of mitochondria and subdivision diameters. Mitochondrial fractional areas were consistently 25% of the total subdivision area and subdivision sizes remained constant throughout development, with an average diameter of 36.5 ± 2.7 µm. Citrate synthase (CS) activities in dark muscle were higher and scaled with a steeper negative slope (b=-0.19) than activities in white muscle (b=-0.09). In addition, the time course of [lactate] was monitored during recovery from anaerobic, burst exercise in white and dark muscle and hemolymph. Burst escape responses were elicited in crabs ranging from 200 g and [lactate] measured. There were no differences among size classes with respect to lactate accumulation as a result of exercise, however, in white fibers from large crabs, lactate continued to increase after exercise, and lactate removal from tissues required a longer period of time relative to small and medium crabs. Differences in lactate removal among size classes were less pronounced in dark fibers. These data suggest that in addition to normal metabolic scaling, aerobic metabolic processes are limited to SA:V and intracellular diffusion constraints in large white muscle fibers

    A Thesis Submitted to the University of North Carolina Wilmington in Partial Fulfillment Of the Requirements for the Degree of Master of Science

    Get PDF
    Global warming has generated extensive research into the sources and removal mechanisms for the greenhouse gases carbon dioxide and methane. Recent research, in which sulfate was added to freshwater and methanogenic brackish sediments, showed that under sulfate-reducing conditions rates of carbon remineralization were more rapid. Therefore, less carbon should be stored in these systems under saline conditions. In the current study, rates of carbon remineralization and storage were compared in Cape Fear River estuarine sediments with naturally-occurring spatial and temporal salinity variations. Trends were not evident along a salinity gradient for the percent organic matter content of sediments, sediment accumulation rates, or the total amount of carbon remineralized. These results show that there are no clear-cut patterns for biogeochemical parameters along a salinity gradient, likely due to variability in both primary productivity and remineralization rates. Although the quantity and quality of organic matter are generally thought to affect remineralization rates, rates in this study were controlled by sulfate concentrations. Most sediments responded to sulfate concentration increases with more rapid remineralization rates, showing that sulfate variations can potentially affect carbon storage in estuarine sediments. An unexpected microbial process was observed during the experiments conducted for this study. The two main processes by which sediments are remineralized in the estuary are sulfate reduction and methane production. Sulfate reduction has generally been shown to out-compete and inhibit methane production via mutually exclusive biogeochemical zonation through competitive inhibition. However, for the first time the coexistence of the two processes at rates of similar magnitudes was observed. A novel approach for calculating below-ground primary production within estuarine wetlands and carbon flux from estuarine wetlands, using sediment remineralization rates, 137Cesium accumulation rates, and above-ground biomass measurements, is presented in this study. The largest amount of carbon fluxed from a site that contained the most above-ground biomass during the growing season. This study has shown that remineralization rates in estuarine sediments could potentially respond to sulfate variations on a short-term basis, supporting the idea that stored carbon could be released to the atmosphere during a rapid sea level rise

    An examination of the appropriateness of the content of the DSM-IV AD/HD symptom criteria for elementary school girls

    Get PDF
    Like many childhood disorders, prevalence rates of AD/HD differ significantly across gender, with male-to-female ratios ranging from 2:1 to 9:1 depending on the sample (APA, 1994). Limited research has been conducted thus far in an effort to better understand these differential prevalence rates. However, it has been proposed that the current symptom descriptions for AD/HD in the DSM-IV may not be fully capturing how females manifest the disorder (Ohan & Johnston, 2005). To address this theory and the existing gap in the literature, this study examined the ability of the current DSM-IV symptom items and some newly proposed gender-sensitive items (Ohan & Johnston, 2005) to predict impairment in elementary school girls. Sixty-three parents and 45 primary classroom teachers of girls ages six to eleven completed packets providing information about the girls. Primary analyses of parent data revealed that a combination of some gender-sensitive items in addition to some DSM-IV items were predictive of overall impairment in girls. However, secondary analyses of teacher data revealed that only some DSM-IV items were predictive of overall impairment. Nonetheless, these findings lend some support for the notion that although the underlying mechanisms of AD/HD may be the same for boys and girls, how this disorder is manifested may be different, and the current diagnostic criteria are not fully capturing how females express AD/HD. Implications for future research and clinical practice were discussed

    Effect of low level fertilization on microplankton in Arctic LTER lakes

    Get PDF
    "Many studies have examined the effects of high level nutrient additions (up to 10x ambient loading rate) to lake ecosystems. This study examined microplankton response to low-level nitrogen and phosphorus additions (nominally 2X ambient loading rate) in lakes with and without fish at the Arctic LTER site. Annual variation in microplankton abundance in experimental and reference lakes was high. Lakes with fish had fewer large microplankton taxa. Overall, the response of microplankton to fertilization was unremarkable except for Vorticella whose average total biomass at 1 meter in the experimental lake containing fish increased significantly over the experimental period (regression coefficient = 1.264; F = 18.27; p = 0.007; d.f. = 5). Microplankton biomass trended downward in reference lakes while remaining relatively stable in experimental lakes, thus a subtle positive response may have occurred. Assessing changes in intermediate trophic levels in response to low-level fertilization is difficult because of high inter-annual variation in temperature and rainfall and a high coefficient of variation in direct count data (range 2 - 244%). Long term experiments and observations (10 years or greater) may be required to definitively assess such subtle impacts."--Abstract from author supplied metadata

    Using SoTL as a Lens to Reflect and Explore for Innovation in Education and Librarianship

    Get PDF
    Across education and librarianship disciplines, ongoing professional education is a key activity that is imperative in helping professionals develop or continue their proficiency in a field. This article explores the relationship between professional development and teaching-based or teaching-focused scholarship, commonly referred to as the Scholarship of Teaching and Learning (SoTL). In doing so, this article asks the broad question, “How can professionals leverage educational opportunities to ask questions about technologies, their organizations, their communities, or their practice?” This article includes two brief case studies that draw on the SoTL method and reflect on enabling factors that help educators and librarians leverage practice-based research techniques. The article concludes with a consideration of issues and enabling factors around practice-based research, particularly in context of professional education settings

    Children at risk : the need for preschool intervention programs for North Carolina's schools

    Get PDF
    This research examines the need for a public preschool program for children who are at risk of school failure in North Carolina. There are some data available that there exists a growing need in our state for a publicly supported preschool intervention program for high risk preschoolers. High risk being defined as children who enter school with a predisposition for difficulties in the elementary grades and in high school. Based on this assumption, the study investigated: 1) the current extent of the problem of high risk children in our state, 2) what is currently being done to meet the needs of high risk children in the public sector statewide, 3) described and analyzed the results of earlier preschool intervention projects nationwide to determine the effects on the participants, 4) demonstrated that additional preschool intervention programs for high risk children in North Carolina would be cost effective, and 5) suggested future program directions and concerns for North Carolina

    The effects of a physical activity program on mood states in college students

    Get PDF
    College students are at risk for adverse mental and physical health. Physical activity (PA) can reduce risks and promote positive mental health; however, less than half (49.9%) of college students meet the American College of Sports Medicine (2017) recommendations for PA. The purpose of this study was to implement and evaluate an evidence-based PA program (#ubwell) designed in collaboration with university counseling services to enhance mood states and promote continued PA in college students. The program was held for 5 weeks. Students (n = 21) completed pre and post measures of perceived health, PA participation, intrinsic motivation, and mood states, and a post program evaluation. Additionally, participants recorded Feeling Scale and Felt Arousal Scale ratings before, during (mid-way) and after each weekly PA session. Results showed intrinsic motivation significantly increased from pre to post (p = .02). Participants experienced increases in positive feelings and energy levels across all PA sessions. However, pre and post measures of perceived health, PA participation, and mood states did not differ. Confounding factors such as participant illness, campus mourning (i.e., deaths of two students the week before), and mid-term/final exams may have influenced results. Possibly, PA provided a coping strategy during those stressful times that maintained mood and PA participation levels. Additional research with larger samples and longer programs may provide greater insight into the benefits of PA programs for mental health and wellness
    corecore