1,621 research outputs found

    A Quantitative Evaluation of Growth in Leptodea Fragilis Before and After the Arrival of Zebra Mussels in Lake Erie

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    The arrival of zebra mussels in the Great Lakes in the 1980’s marked several environmental changes, most notably in freshwater mussels in the Unionidae. There are no studies of population demographics of native Great Lake species before this period of time. In this study, several recent shell collections of Leptodea fragilis, a fast-growing freshwater mussel, were made on various beaches along Lake Erie. To compare the effects of the zebra mussels on L. fragilis, we compared growth rates, determined from size and estimated age of shells, to additional collections of L. fragilis from 1941 to 1967available at the Cleveland Museum of Natural History. The growth rates of this species are exceptional for their speed among freshwater mussels. A modern comparison of growth rates and age are presented with a sexually dimorphic unionid river species, Lampsilis siliquoidea, that were collected in Summer 2013. We hypothesized that the arrival of zebra mussels could affect the growth rate of L. fragilis by selecting on age of reproduction or growth to reach a minimum size for reproduction, results that could shift growth curves and/or age demography of current populations, and help them persist where zebra mussels remain abundant.https://engagedscholarship.csuohio.edu/u_poster_2013/1006/thumbnail.jp

    The Impact of Dreissenid Mussels on Growth of the Fragile Papershell (Leptodea fragilis), the Most Abundant Unionid Species in Lake Erie

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    The arrival of zebra mussels (Dreissena polymorpha (Pallas, 1771)) and subsequently quagga mussels (Dreissena bugensis Andrusov, 1897) (Dreissenidae) in the Great Lakes in the 1980s induced many changes, most notably the devastation of native freshwater mussel species. Recently, empty shells of the fragile papershell (Leptodea fragilis (Rafinesque, 1820)) have become common, particularly in the western basin of Lake Erie, suggesting that this fast-growing species may be increasing in numbers in the lake. To examine continued competition with dreissenids, shell age and length of L. fragilis were used to contrast lifespan and growth rate, estimated as the slope of age on shell length, for shells from two beach localities where byssal threads were present on most shells and two sites where dreissenids were rare or absent. Few recent shells from Lake Erie beaches exceeded 5 years of age, and byssal thread counts were more numerous on older shells. Growth and lifespan were estimated to be significantly lower where dreissenid mussels remained numerous than when measured either from historic collections along Lake Erie or from protected populations. Therefore, even for this early-reproducing species, competition from dreissenids may continue to interfere with growth and shorten lifespan, which are effects few other unionid species can likely tolerate sufficiently to sustain population growt

    Mitochondrial DNA Variation in the Eastern Pondmussel, Ligumia nasuta (Bivalvia: Unionoida), in the Great Lakes Region

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    Most freshwater mussel species in the Great Lakes colonized the region from the Mississippi River basin and few appear to have colonized from Atlantic coast rivers. The Eastern Pondmussel, Ligumia nasuta, is widespread along the Atlantic coast but occurs elsewhere only in the Great Lakes, suggesting that it is one of the few Great Lakes species of Atlantic origin. Great Lakes populations are now imperiled following invasion of the lakes by dreissenid mussels. We examined patterns of diversity in the mitochondrial CO1 and ND1 genes in L. nasuta populations in the Great Lakes and in Atlantic coast rivers. Genetic diversity was low in Great Lakes populations and included only one CO1 and two ND1 haplotypes, all of which were also found in Atlantic coast populations. Genetic diversity was higher in Atlantic coast populations and included four CO1 and six ND1 haplotypes. Pairwise ФST revealed significant genetic differentiation for both genes between Atlantic coast and Great Lakes populations but not within Great Lakes populations. These results suggest that all populations of L. nasuta in the Great Lakes are derived from a single, small founder group that colonized from an Atlantic coast river. As such, Great Lakes populations may be considered a single management unit and conservation efforts based on propagation or translocation should be limited to use of Great Lakes source stock to prevent introduction of non-native haplotypes

    Cancer Biology Data Curation at the Mouse Tumor Biology Database (MTB)

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    Many advances in the field of cancer biology have been made using mouse models of human cancer. The Mouse Tumor Biology (MTB, "http://tumor.informatics.jax.org":http://tumor.informatics.jax.org) database provides web-based access to data on spontaneous and induced tumors from genetically defined mice (inbred, hybrid, mutant, and genetically engineered strains of mice). These data include standardized tumor names and classifications, pathology reports and images, mouse genetics, genomic and cytogenetic changes occurring in the tumor, strain names, tumor frequency and latency, and literature citations.

Although primary source for the data represented in MTB is peer-reviewed scientific literature an increasing amount of data is derived from disparate sources. MTB includes annotated histopathology images and cytogenetic assay images for mouse tumors where these data are available from The Jackson Laboratory’s mouse colonies and from outside contributors. MTB encourages direct submission of mouse tumor data and images from the cancer research community and provides investigators with a web-accessible tool for image submission and annotation. 

Integrated searches of the data in MTB are facilitated by the use of several controlled vocabularies and by adherence to standard nomenclature. MTB also provides links to other related online resources such as the Mouse Genome Database, Mouse Phenome Database, the Biology of the Mammary Gland Web Site, Festing's Listing of Inbred Strains of Mice, the JAX® Mice Web Site, and the Mouse Models of Human Cancers Consortium's Mouse Repository. 

MTB provides access to data on mouse models of cancer via the internet and has been designed to facilitate the selection of experimental models for cancer research, the evaluation of mouse genetic models of human cancer, the review of patterns of mutations in specific cancers, and the identification of genes that are commonly mutated across a spectrum of cancers.

MTB is supported by NCI grant CA089713

    Neutrophil gelatinase-associated lipocalin: its response to hypoxia and association with acute mountain sickness.

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    Acute Mountain Sickness (AMS) is a common clinical challenge at high altitude (HA). A point-of-care biochemical marker for AMS could have widespread utility. Neutrophil gelatinase-associated lipocalin (NGAL) rises in response to renal injury, inflammation and oxidative stress. We investigated whether NGAL rises with HA and if this rise was related to AMS, hypoxia or exercise. NGAL was assayed in a cohort (n = 22) undertaking 6 hours exercise at near sea-level (SL); a cohort (n = 14) during 3 hours of normobaric hypoxia (FiO2 11.6%) and on two trekking expeditions (n = 52) to over 5000 m. NGAL did not change with exercise at SL or following normobaric hypoxia. During the trekking expeditions NGAL levels (ng/ml, mean ± sd, range) rose significantly (P < 0.001) from 68 ± 14 (60-102) at 1300 m to 183 ± 107 (65-519); 143 ± 66 (60-315) and 150 ± 71 (60-357) at 3400 m, 4270 m and 5150 m respectively. At 5150 m there was a significant difference in NGAL between those with severe AMS (n = 7), mild AMS (n = 16) or no AMS (n = 23): 201 ± 34 versus 171 ± 19 versus 124 ± 12 respectively (P = 0.009 for severe versus no AMS; P = 0.026 for mild versus no AMS). In summary, NGAL rises in response to prolonged hypobaric hypoxia and demonstrates a relationship to the presence and severity of AMS

    The strategic under-reporting of bank risk

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    We show that banks significantly under-report the risk in their trading book when they have lower equity capital. Specifically, a decrease in a bank’s equity capital results in substantially more violations of its self-reported risk levels in the following quarter. The under-reporting is especially high during the critical periods of high systemic risk and for banks with larger trading operations. We exploit a discontinuity in the expected benefit of under-reporting present in Basel regulations to provide further support for a causal link between capital-saving incentives and under-reporting. Overall, we show that banks’ self-reported risk measures become least informative precisely when they matter the most

    Pilot and feasibility study of serum chemokines as markers to distinguish prostatic disease in men with low total serum PSA

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    BACKGROUND The incidence and prevalence of both benign prostatic hypertrophy (BPH) and prostate cancer (PCa) increase with the aging process. Our laboratory recently showed that the chemokines CXCL5 and CXCL12, which normally function as inflammatory mediators, are secreted at higher levels by aging prostate stromal fibroblasts and elicit proliferative responses from both prostate stromal fibroblast and epithelial cells. Because both CXCL5 and CXCL12 are secreted molecules, we hypothesized that their levels in patient serum might serve as biomarkers to distinguish between BPH and PCa. METHODS Serum CXCL5 and CXCL12 levels were determined using sandwich ELISAs for 51 men demonstrating low serum PSA values of ≤10 ng/ml who underwent diagnostic needle biopsy for the detection of PCa. The bivariate relationship of circulating chemokine levels, age, and disease status in the prostate was tested using the Wilcoxon rank-sum test. Results Total serum CXCL12 levels were significantly higher for men who were biopsy positive compared to those who were biopsy negative for cancer and histological prostatitis ( P  = 0.050). Among men who were biopsy negative for PCa, total serum CXCL5 levels were inversely associated with prostate volume and were significantly higher in men with concomitant BPH and histological prostatitis compared to those without evidence of prostatic disease ( P  < 0.003). CONCLUSIONS The results of this pilot and feasibility study suggest that serum or plasma CXCL5 and CXCL12 levels may potentially distinguish between BPH and PCa among patients presenting with low serum PSA, and may be useful toward facilitating decisions to perform diagnostic needle biopsy in this patient population. Prostate 68: 442–452, 2008. © 2008 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57914/1/20717_ftp.pd

    Can scribes boost FPs\u27 efficiency and job satisfaction

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    Purpose: Research in other medical specialties has shown that the addition of medical scribes to the clinical team enhances physicians\u27 practice experience and increases productivity. To date, literature on the implementation of scribes in primary care is limited. To determine the feasibility and benefits of implementing scribes in family medicine, we undertook a pilot mixed- method quality improvement (QI) study. Methods: In 2014, we incorporated 4 part-time scribes into an academic family medicine practice consisting of 7 physicians. We then measured, via survey and time-tracking data, the impact the scribes had on physician office hours and productivity, time spent on documentation, perceptions of work-life balance, and physician and patient satisfaction. Results: Six of the 7 faculty physicians participated. This study demonstrated that the use of scribes in a busy academic primary care practice substantially reduced the amount of time that family physicians spent on charting, improved work-life balance, and had good patient acceptance. Specifically, the physicians spent an average of 5.1 fewer hours/week (hrs/wk) on documentation, while various measures of productivity revealed increases ranging from 9.2% to 28.8%. Perhaps most important of all, when the results of the pilot study were annualized, they were projected to generate 168,600peryearmorethantwicethe168,600 per year--more than twice the 79,500 annual cost of 2 full-time equivalent scribes. Surveys assessing work-life balance demonstrated improvement in the physicians\u27 perception of the administrative burden/paperwork related to practice and a decrease in their perception of the extent to which work encroached on their personal lives. In addition, survey data from 313 patients at the time of their ambulatory visit with a scribe present revealed a high level of comfort. Likewise, surveys completed by physicians after 55 clinical sessions (ie, blocks of consecutive, uninterrupted patient appointments; there are usually 2 sessions per day) revealed good to excellent ratings more than 90% of the time. Conclusion: In an outpatient family medicine clinic, the use of scribes substantially improved physicians\u27 efficiency, job satisfaction, and productivity without negatively impacting the patient experience
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