159 research outputs found
Clearcutting in Appalachia: Impacts on Stream Water Quality in an Appalachian Watershed
Clearcutting forests has the potential to impact the water quality of high water headwater streams. In this study, we measured the effect of forest clearcut events on parameters of stream water quality within Michaux State Forest. The watershed of two streams included 2.1% and 11.6% of the total catchment in clearcuts, while the other 4 watersheds had no clearcuts. We measured pH, electrical conductivity, total suspended solids, and nitrate (ppm) and phosphate (ppm) concentrations from six different tributary streams. Mann-Whitney U tests maintain no statistical difference observed between pH (U= 4.00, p= 1.00), temperature (U=1.00, p=0.165), electrical conductivity (U=2.00, p=0.355), suspended solids (U=2.00, p=0.325), nitrate concentration (U=2.00, p=0.264), or phosphate concentration (U=2.00, p=0.340). However, post-hoc analysis confirms stream 6 as an upper outlier for electrical conductivity (EC= 86.8 uS). This may be due to this site’s proximity to a busy road. These results suggest that there is no significant impact of clearcutting on stream water quality in Michaux State Forest. However, further repetition of this experiment would be necessary to make this conclusion statistically robust
A Literature Study of the Use of Electrophoresis to Replace the Electron Transport Chain in Photosynthesis within Aquatic Plants in the Absence of UV Light
Undergraduate
Theoretica
The Effectiveness of an Artificial Floating Wetland to Remove Nutrients in an Urban Stream: A Pilot-Study in the Chicago River, Chicago, IL USA
Ever expanding urbanized landscapes are increasingly impacting streams that run through them. Among other stressors, urban streams often are host to elevated concentrations of nutrients, salts, and heavy metals. The pollutants, coupled with high temperatures, are drivers of ecosystem degradation in urban streams. The installation of artificial floating wetlands (AFWs) has been successful in mitigating the effects of urbanization in lakes and wastewater treatment ponds, but rarely have they been tested in streams. This pilot-study examined the ability of an AFW to improve water quality in an urban stream. The small, 90 m2 AFW was installed to improve the aquatic habitat and aesthetics of a small section of the Chicago River, Chicago, IL USA.Water samples and in-situ measurements were collected from the surface and at 0.3 m depth of upstream and downstream of the AFW. Samples were analyzed for nitrate-as-nitrogen, phosphate, chloride, and heavy metals. Comparison of upstream and downstream waters showed that the AFW lowered the concentrations of nitrate-as-nitrogen and phosphate during the growing season by 6.9% and 6.0%, respectively. Nitrate was also removed during the dormant season; however, phosphate was not removed during that time. Plant or microbial uptake of the nutrients are believed to be the dominant mechanisms in the growing season with denitrification serving as the primary pathway in the dormant season. Despite not having a measurable effect on the water temperature, the AFW was an effective means to reduce concentrations of nitrate and phosphorus, decreasing the potential for eutrophication
Screening for eating disorders in adolescents with chronic pain: the Eating Attitudes Test– 16–Chronic Pain
Background Few measures have been validated to screen for eating disorders (ED) in youth with chronic pain. We conducted confirmatory (CFA) of two established factor structures of the Eating Attitudes Test-26 (EAT-26) in a sample of youth with chronic pain attending an intensive interdisciplinary pain treatment (IIPT) program and examined the validity of the best-fitting model in predicting ED diagnoses in this sample.
Methods Participants were 880 adolescents (M age = 16.1, SD = 2.1) consecutively admitted into an IIPT program who completed the EAT-26 upon admission. CFA was conducted and in the case of inadequate fit, EFA was planned to identify alternative models. Factors of the best-fitting model were included in a logistic regression analysis to predict ED diagnoses.
Results The TLIs (0.70; 0.90), RMSEAs (0.09; 0.07) and CFIs (0.73; 0.92) suggested poor fit of one model and adequate of the second model. Goodness of fit indices from EFA (TLI:0.85, RMSEA:0.06) did not outperform the fit of the second CFA. As such, the second model was retained with the exception of one factor. The items loaded onto a 16-item, five factor model: Fear of Getting Fat, Social Pressure to Gain Weight, Eating-Related Control, Eating-Related Guilt and Food Preoccupation. Based on chart review, 19.1% of the participants were diagnosed with an eating disorder. Logistic regression analyses indicated the new 16-item measure and Fear of Getting Fat, significantly predicted an ED diagnosis that did not include avoidant restrictive food intake disorder (ARFID) and Social Pressure to Gain Weight significantly predicted a diagnosis of ARFID
Setting a common standard in clinical skills assessment: The experience of the California Consortium for the Assessment of Clinical Competence
Objective or purpose of innovation: To identify common clinical skills competency thresholds across schools by centralizing standard setting for a multi-institutional assessment.
Background and/or theoretical framework and importance to the field: The California Consortium for the Assessment of Clinical Competence (CCACC) comprises 10 medical schools that administer a common multi-station clinical skills assessment (CPX). Previously, each institution determined their own, largely norm-referenced passing thresholds for the examination. With the elimination of USMLE Step 2 CS, there is a recognized need for robust clinical skills assessment beyond the individual institutional level. A collaboratively developed, multi-institutional examination with passing thresholds established via a rigorous process offers greater validity evidence for summative decisions made based on its results. Accordingly, the CCACC undertook centralized, criterion-based standard setting for the CPX.
Design: Passing thresholds for the six core CPX cases were determined via two methods: modified Angoff, using expert raters from multiple institutions, and borderline regression, using global encounter ratings assigned by standardized patients. Results from the two methods were compared to each other and to institutions’ prior thresholds.
Outcomes: Both methods yielded the same cumulative cut score based on averages across all cases (70%), but exhibited variation between individual cases, suggesting case-specificity. Compared with prior thresholds, some institutions’ pass rates would have been higher using the common criterion-referenced cut score, while others would have been lower.
Innovation’s strengths and limitations: This study demonstrates the feasibility of centralizing standard setting across multiple institutions using two criterion-based methods. Standardized patient ratings may generate similar passing thresholds to those determined by clinicians. Further studies are necessary to determine whether these findings generalize to other case types and how best to apply centralized standards within each institution’s context.
Feasibility and generalizability: The CCACC’s standard setting approaches may be applied across other institutions sharing an assessment, allowing for comparison of learner performance to a common standard. Given the similar results, the choice of method may be determined by resource availability
Ecological and social strategies for managing fisheries using the Resist-Accept- Direct (RAD) framework
Fisheries management is a complex task made even more challenging by rapid and unprecedented socioecological transformations associated with climate change. The Resist-Accept- Direct (RAD) framework can be a useful tool to support fisheries management in facing the high uncertainty and variability associated with aquatic ecosystem transformations. Here, RAD strategies are presented to address ecological goals for aquatic ecosystems and social goals for fisheries. These strategies are mapped on a controllability matrix which explores the ability to guide a system\u27s behaviour towards a desired state based on ecological responsiveness and societal receptivity to change. Understanding and improving the controllability of aquatic systems and fisheries can help managers to maintain the broadest suite of available RAD management strategies
Comparative analysis of mycobacterium and related actinomycetes yields insight into the evolution of mycobacterium tuberculosis pathogenesis
<p>Abstract</p> <p>Background</p> <p>The sequence of the pathogen <it>Mycobacterium tuberculosis </it>(<it>Mtb</it>) strain <it>H37Rv </it>has been available for over a decade, but the biology of the pathogen remains poorly understood. Genome sequences from other <it>Mtb </it>strains and closely related bacteria present an opportunity to apply the power of comparative genomics to understand the evolution of <it>Mtb </it>pathogenesis. We conducted a comparative analysis using 31 genomes from the Tuberculosis Database (TBDB.org), including 8 strains of <it>Mtb </it>and <it>M. bovis</it>, 11 additional Mycobacteria, 4 Corynebacteria, 2 Streptomyces, <it>Rhodococcus jostii RHA1, Nocardia farcinia, Acidothermus cellulolyticus, Rhodobacter sphaeroides, Propionibacterium acnes</it>, and <it>Bifidobacterium longum</it>.</p> <p>Results</p> <p>Our results highlight the functional importance of lipid metabolism and its regulation, and reveal variation between the evolutionary profiles of genes implicated in saturated and unsaturated fatty acid metabolism. It also suggests that DNA repair and molybdopterin cofactors are important in pathogenic Mycobacteria. By analyzing sequence conservation and gene expression data, we identify nearly 400 conserved noncoding regions. These include 37 predicted promoter regulatory motifs, of which 14 correspond to previously validated motifs, as well as 50 potential noncoding RNAs, of which we experimentally confirm the expression of four.</p> <p>Conclusions</p> <p>Our analysis of protein evolution highlights gene families that are associated with the adaptation of environmental Mycobacteria to obligate pathogenesis. These families include fatty acid metabolism, DNA repair, and molybdopterin biosynthesis. Our analysis reinforces recent findings suggesting that small noncoding RNAs are more common in Mycobacteria than previously expected. Our data provide a foundation for understanding the genome and biology of <it>Mtb </it>in a comparative context, and are available online and through TBDB.org.</p
Managing for RADical ecosystem change: applying the Resist-Accept- Direct (RAD) framework
Ecosystem transformation involves the emergence of persistent ecological or social–ecological systems that diverge, dramatically and irreversibly, from prior ecosystem structure and function. Such transformations are occurring at increasing rates across the planet in response to changes in climate, land use, and other factors. Consequently, a dynamic view of ecosystem processes that accommodates rapid, irreversible change will be critical for effectively conserving fish, wildlife, and other natural resources, and maintaining ecosystem services. However, managing ecosystems toward states with novel structure and function is an inherently unpredictable and difficult task. Managers navigating ecosystem transformation can benefit from considering broader objectives, beyond a traditional focus on resisting ecosystem change, by also considering whether accepting inevitable change or directing it along some desirable pathway is more feasible (that is, practical and appropriate) under some circumstances (the RAD framework). By explicitly acknowledging transformation and implementing an iterative RAD approach, natural resource managers can be deliberate and strategic in addressing profound ecosystem change
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