7,179 research outputs found

    Report card for W.L. Treadwell from UNC, 20 March 1849

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    https://egrove.olemiss.edu/aldrichcorr_b/1212/thumbnail.jp

    Report card for W.L. Treadwell from UNC, 1 June 1849

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    https://egrove.olemiss.edu/aldrichcorr_b/1213/thumbnail.jp

    The role of giant vacuoles and pores in the endothelium of Schlemm’s canal in regulating segmental aqueous outflow

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    Primary open-angle glaucoma (POAG) is one of the leading causes of blindness worldwide. The only modifiable risk factor for POAG is elevated intraocular pressure, resulting from increased aqueous humor production or decreased drainage. Resistance to drainage in the aqueous outflow pathway is believed to reside in the juxtacanalicular connective tissue (JCT) and to be modulated by the inner wall (IW) endothelium of Schlemm’s canal (SC); however, the mechanisms that increase resistance in POAG remain unclear. To cross the IW, aqueous humor passes through I-pores on giant vacuoles (GVs) or B-pores between adjacent endothelial cells. Additionally, outflow around the circumference of the eye is segmental, or non-uniform, and fluorescent tracers can be used to label areas of high-flow and non-flow. The morphological differences in the endothelial cells of SC and their GVs in high- vs. non-flow areas have not been fully elucidated. In this project, we investigated the role of GVs and pores in the IW endothelial cells of SC in regulating segmental outflow in human eyes. We used serial block-face scanning electron microscopy to generate thousands of serial images and visualize these structures in 3D at the ultrastructural level. First, we 3D-reconstructed 45 individual IW cells and their GVs and quantified the number of connections each cell makes with the underlying JCT matrix/cells. We found that cells in high-flow areas made significantly fewer connections to JCT matrix/cells compared to cells in non-flow areas. Secondly, we analyzed 3,302 GVs for I-pores and basal openings and found a significantly greater percentage of GVs with both basal openings and I-pores in high-flow area compared to non-flow area, suggesting this type of GVs form a channel through which aqueous humor passes from JCT to SC. We also found that GVs with I-pores were significantly larger than those without I-pores. Our results suggest that decreasing number of cellular connections and increasing number of GVs with pores may be potential strategies to increase the amount of high-flow area and aqueous outflow for glaucoma treatment. Together, these studies add to our understanding of the role of GVs and pores in regulating segmental flow around the eye

    Observing Oceans in Tightly Packed Planetary Systems: Perspectives from Polarization Modeling of the TRAPPIST-1 System

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    The recently discovered TRAPPIST-1 system is exciting due to the possibility of several rocky, Earth-sized planets harboring liquid water on their surface. To assess the detectability of oceans on these planets, we model the disk-integrated phase curves and polarization signals for planets in this system for reflected starlight. We examine four cases: (1) dry planet, (2) cloud-covered planet, (3) planet with regional-scale oceans, and (4) planet with global oceans. Polarization signals are strongest for optically thin (≾ 0.1) atmospheres over widespread oceans, with the degree of polarization being up to 90% for a single planet or on the order of 100 parts per billion for the star–planet system. In cases where reflected light from different planets in a tightly packed system cannot be separated, observing in polarized light allows for up to a tenfold increase in star–planet contrast compared to photometric observations alone. However, polarization from other sources, such as atmospheric scattering and cloud variability, will pose major challenges to the detection of glint (specularly reflected starlight) polarization signals. Planned telescopes like LUVOIR may be capable of observing glint from Earth-like planets around Sun-like stars, and if equipped with a polarimeter can significantly improve our ability to detect and study oceans on rocky exoplanets

    The potential for modification in cloning and vitrification technology to enhance genetic progress in beef cattle in Northern Australia

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    AbstractRecent advances in embryology and related research offer considerable possibilities to accelerate genetic improvement in cattle breeding. Such progress includes optimization and standardization of laboratory embryo production (in vitro fertilization – IVF), introduction of a highly efficient method for cryopreservation (vitrification), and dramatic improvement in the efficiency of somatic cell nuclear transfer (cloning) in terms of required effort, cost, and overall outcome. Handmade cloning (HMC), a simplified version of somatic cell nuclear transfer, offers the potential for relatively easy and low-cost production of clones. A potentially modified method of vitrification used at a centrally located laboratory facility could result in cloned offspring that are economically competitive with elite animals produced by more traditional means. Apart from routine legal and intellectual property issues, the main obstacle that hampers rapid uptake of these technologies by the beef cattle industry is a lack of confidence from scientific and commercial sources. Once stakeholder support is increased, the combined application of these methods makes a rapid advance toward desirable traits (rapid growth, high-quality beef, optimized reproductive performance) a realistic goal. The potential impact of these technologies on genetic advancement in beef cattle herds in which improvement of stock is sought, such as in northern Australia, is hard to overestimate

    Monitoring neonicotinoid exposure for bees in rural and peri-urban areas of the UK during the transition from pre- to post-moratorium

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    Concerns regarding the impact of neonicotinoid exposure on bee populations recently led to an EU-wide moratorium on the use of certain neonicotinoids on flowering crops. Currently evidence regarding the impact, if any, the moratorium has had on bees’ exposure is limited. We sampled pollen and nectar from bumblebee colonies in rural and peri-urban habitats in three UK regions; Stirlingshire, Hertfordshire and Sussex. Colonies were sampled over three years; prior to the ban (2013), during the initial implementation when some seed-treated winter-sown oilseed rape was still grown (2014), and following the ban (2015). To compare species-level differences, in 2014 only, honeybee colonies in rural habitats were also sampled. Over half of all samples were found to be contaminated (n=408), with thiamethoxam being the compound detected at the highest concentrations in honeybee- (up to 2.29 ng/g in nectar in 2014, median≤0.1 ng/g, n=79) and bumblebee-collected pollen and nectar (up to 38.77 ng/g in pollen in 2013, median ≤0.12 ng/g, n=76). Honeybees were exposed to higher concentrations of neonicotinoids than bumblebees in 2014. While neonicotinoid exposure for rural bumblebees declined post-ban (2015), suggesting a positive impact of the moratorium, the risk of neonicotinoid exposure for bumblebees in peri-urban habitats remained largely the same between 2013 and 2015

    An investigation of assumptions made in estimating genetic parameters and predicting genetic gain in a Eucalyptus nitens breeding programme in South Africa

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    It is important to have an understanding of the population genetics and validity of the pertinent underlying assumptions of a species in order to design an effective breeding strategy. In a South African breeding population of Eucalyptus nitens, various scenarios investigating a range of assumptions were developed and used to predict genetic gain in the F2. These were compared with realised gains achieved in a series of genetic gain trials. In the two scenarios using firstly, actual flowering for family (provenance) and, secondly, estimated flowering after 30 % roguing of poor families, a coefficient of relationship of 0.33 resulted in predictions closest to realised gain, on average. The statistical information suggested that outcrossing in the seed orchards was[80 %. Indications were that the effects were additive, and that very little or no heterosis had occurred, due to the still significant provenance effects and the lack of provenance rank changes in the F2. The custom of assuming a degree of inbreeding (and using a coefficient of relationship of 0.33) and of including provenance effects in the models, on average resulted in genetic gain predictions which were very similar to the realised genetic gains in this population of E. nitens.Masonite Ltd., Mondi Ltd, NCT Forestry Co-Operative Ltd., PG Bison, TWK Ltd. and York Timbers Ltd.http://link.springer.com/journal/110562016-01-31hb201

    Descriptive and Substantive Representation in Congress: Evidence from 80,000 Congressional Inquiries

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    A vast literature debates the efficacy of descriptive representation in legislatures. Though studies argue it influences how communities are represented through constituency service, they are limited since legislators’ service activities are unobserved. Using Freedom of Information Act (FOIA) requests, we collected 88,000 records of communication between members of the U.S. Congress and federal agencies during the 108th–113th Congresses. These legislative interventions allow us to examine members’ “follow‐through” with policy implementation. We find that women, racial/ethnic minorities, and veterans are more likely to work on behalf of constituents with whom they share identities. Including veterans offers leverage in understanding the role of political cleavages and shared experiences. Our findings suggest that shared experiences operate as a critical mechanism for representation, that a lack of political consensus is not necessary for substantive representation, and that the causal relationships identified by experimental work have observable implications in the daily work of Congress.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150606/1/ajps12443-sup-0001-SuppMat.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150606/2/ajps12443.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150606/3/ajps12443_am.pd

    Endoscopic closure of transmural bladder wall perforations

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    Background: Traditionally, intraperitoneal bladder perforations caused by trauma or iatrogenic interventions have been treated by open or laparoscopic surgery. Additionally, transvesical access to the peritoneal cavity has been reported to be feasible and useful for natural orifice translumenal endoscopic surgery (NOTES) but would be enhanced by a reliable method of closing the vesicotomy. Objective: To assess the feasibility and safety of an endoscopic closure method for vesical perforations using a flexible, small-diameter endoscopic suturing kit in a survival porcine model. Design, setting, and participants: This pilot study was performed at the University of Minho, Braga, Portugal, using six anesthetized female pigs. Interventions: Closure of a full-thickness longitudinal incision in the bladder dome (up to 10 mm in four animals and up to 20 mm in two animals) with the endoscopic suturing kit using one to three absorbable stitches. Measurements: The acute quality of sealing was immediately tested by distending the bladder with methylene-blue dye under laparoscopic control (in two animals). Without a bladder catheter, the animals were monitored daily for 2 wk, and a necropsy examination was performed to check for the signs of peritonitis, wound dehiscence, and quality of healing. Results and limitations: Endoscopic closure of bladder perforation was carried out easily and quickly in all animals. The laparoscopic view revealed no acute leak of methylene-blue dye after distension of the bladder. After recovery from anaesthesia, the pigs began to void normally, and no adverse event occurred. Postmortem examination revealed complete healing of vesical incision with no signs of infection or adhesions in the peritoneal cavity. No limitations have yet been studied clinically. Conclusions: This study demonstrates the feasibility and the safety of endoscopic closure of vesical perforations with an endoscopic suturing kit in a survival porcine model. This study provides support for further studies using endoscopic closure of the bladder which may lead to a new era in management of bladder rupture and adoption of the transvesical port in NOTES procedures
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