429 research outputs found

    Bamboo Nutritional Composition, Biomass Production, and Palatability to Giant Pandas: Disturbance and Temporal Effects

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    The giant panda (Ailuropoda melanoleuca) subsists on bamboo, but lacks gastrointestinal modifications for fiber digestion. Pandas display dietary selectivity for certain plant parts; however, cues for selection are unknown, and few have examined panda feeding behavior and bamboo nutrient composition simultaneously. Bamboos are clonal plants, with seasonal cycles of nutrient accumulation related to peak photosynthesis and recruitment. These cycles can be destabilized by aboveground disturbance; however, effects of disturbance on nutritional quality and sustainability of bamboo for primary consumers have not been studied. I examined 4 factors that may contribute to bamboo nutritional quality or sustainable harvest: season, ramet maturity and age, and disturbance. I conducted a 3-year study with Phyllostachys aureosulcata (PLLAU), P. glauca (PLLGL), and P. rubromarginata (PLLRU), at the Shelby County AgriCenter, Memphis TN, applying 3 disturbance treatments in a replicated split-plot design: control, 3% and 20% annual removal of biomass. Bamboo was sampled 8 times/year and divided into shoot, leaf, and culm (central stem) for analysis of crude protein (CP), neutral- and acid-detergent fiber (NDF and ADF), ash, lipid, minerals, and acid-insoluble ash (AIA). I quantified bamboo-stand production, maturity, recruitment and mortality. Biomass removed from PLLAU was used in diet-selection trials with 2 giant pandas, observing consumption of plant parts and bamboo from different disturbance treatments, and sampling bamboo for allelochemical and starch analysis. Disturbance effects were evident only for branch and culm dry mass in PLLRU. In Year 2, drought conditions and peak roosting blackbird populations confounded results. Defoliation and guano deposition preceded changes to soil chemistry, bamboo composition, and stand structure; recruitment increased for PLLRU. After accounting for confounding factors, less-mature bamboo had greater concentrations of most nutrients, but less NDF, ADF, and K. Two-year-old ramets had greater CP, NDF, lipid, P, K, S, and Cu, but less Ca and Fe, than 1-year-old ramets. I confirmed seasonal plant-part selection by pandas, but found no correlation between leaf consumption and AIA concentration. Culm starch analyses were insufficient to establish a clear pattern. I recommend further investigation of non-structural carbohydrates in bamboo, and palatability testing of undisturbed versus disturbed bamboo, which I was unable to examine

    Protein Nutrition of Southern Plains Small Mammals: Immune Response to Variation in Maternal and Offspring Dietary Nitrogen

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    Maternal nutrition during pregnancy and postnatal offspring nutrition may influence offspring traits. We investigated the effects of maternal and post weaning offspring dietary nitrogen on immune function and hematology in two species of rodent: the hispid cotton rat (Sigmodon hispidus), a primarily herbivorous rodent, and the fulvous harvest mouse (Reithrodontomys fulvescens), an omnivore. These two species responded differently to the same levels of treatment, with cotton rats primarily influenced by maternal diet and harvest mice by post weaning offspring diet. Cotton rats born to mothers on high-nitrogen diets had lower values of mean corpuscle volume and hemoglobin and greater concentrations of serum immunoglobulins. Spleen size, cell-mediated immune response, and the number of splenocytes and thymic platelets were lower in cotton rats born to mothers on low- and high-nitrogen diets. High-nitrogen offspring diet increased kidney and liver mass in cotton rats. Harvest mice had increased kidney mass on high-nitrogen maternal diets; however, changes in offspring diet after weaning reduced hematological parameters in individuals fed low nitrogen diets. Body length was also affected, with harvest mice born to mothers fed low- and high-nitrogen diets having shorter lengths. Splenocyte cellular activity was greater in offspring born to mothers on high-nitrogen diets in both species

    Soft Target Security: Examining the Need and Readiness for Sector-Specific Standards

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    This report was commissioned by The National Counterterrorism Innovation, Technology, and Education Center (NCITE), a Department of Homeland Security (OHS) Center of Excellence (COE), to inform policymakers on issues related to the potential development of sector-specific security standards for soft targets. The findings and recommendations outlined in this research are intended to guide the development of policies and initiatives to address their unique security challenges. A soft target is a publicly-accessible location, venue or event that typically attracts groups of people and is vulnerable to attack due to a lack of robust protection measures. Many soft targets are privately owned, operate with limited resources, and struggle to balance security, aesthetics, and ease of accessibility. Their open nature makes them attractive to a variety of threat actors, from terrorists to malicious insiders. They have unique environments, cultures, operational practices, and vulnerabilities. The research addresses these critical questions: Are current security standards and guidance for soft targets both utilized and sufficient? Could customized, context-specific standards fill an existing gap and improve efforts to secure soft target venues

    Comparison of Quarterly and Yearly Calibration Data for Propensity Score Adjusted Web Survey Estimates

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    While web surveys have become increasingly popular as a method of data collection, there is concern that estimates obtained from web surveys may not reflect the target population of interest. Web survey estimates can be calibrated to existing national surveys using a propensity score adjustment, although requirements for the size and collection timeline of the reference data set have not been investigated. We evaluate health outcomes estimates from the National Center for Health Statistics’ Research and Development web survey. In our study, the 2016 National Health Interview Survey as well as its quarterly subsets are considered as reference datasets for the web data. It is demonstrated that the calibrated health estimates overall vary little when using the quarterly or yearly data, suggesting that there is flexibility in selecting the reference dataset. This finding has many practical implications for constructing reference data, including the reduced cost and burden of a smaller sample size and a more flexible timeline

    Policy Feedback and the Politics of the Affordable Care Act

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    There is a large body of literature devoted to how “policies create politics” and how feedback effects from existing policy legacies shape potential reforms in a particular area. Although much of this literature focuses on self‐reinforcing feedback effects that increase support for existing policies over time, Kent Weaver and his colleagues have recently drawn our attention to self‐undermining effects that can gradually weaken support for such policies. The following contribution explores both self‐reinforcing and self‐undermining policy feedback in relationship to the Affordable Care Act, the most important health‐care reform enacted in the United States since the mid‐1960s. More specifically, the paper draws on the concept of policy feedback to reflect on the political fate of the ACA since its adoption in 2010. We argue that, due in part to its sheer complexity and fragmentation, the ACA generates both self‐reinforcing and self‐undermining feedback effects that, depending of the aspect of the legislation at hand, can either facilitate or impede conservative retrenchment and restructuring. Simultaneously, through a discussion of partisan effects that shape Republican behavior in Congress, we acknowledge the limits of policy feedback in the explanation of policy stability and change

    Verbal fluency in HIV infection: A meta-analytic review

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    Given the largely prefrontostriatal neuropathogenesis of HIV-associated neurobehavioral deficits, it is often presumed that HIV infection leads to greater impairment on letter versus category fluency. A meta-analysis of the HIV verbal fluency literature was conducted (k = 37, n = 7110) to assess this hypothesis and revealed generally small effect sizes for both letter and category fluency, which increased in magnitude with advancing HIV disease severity. Across all studies, the mean effect size of category fluency was slightly larger than that of letter fluency. However, the discrepancy between category and letter fluency dissipated in a more conservative analysis of only those studies that included both tests. Thus, HIV-associated impairments in letter and category fluency are of similar magnitude, suggesting that mild word generation deficits are evident in HIV, regardless of whether traditional letter or semantic cues are used to guide the word search and retrieval process (JINS, 2007, 13, 183–189.

    Questioning the rise of gelatinous zooplankton in the World's oceans

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    During the past several decades, high numbers of gelatinous zooplankton species have been reported in many estuarine and coastal ecosystems. Coupled with media-driven public perception, a paradigm has evolved in which the global ocean ecosystems are thought to be heading toward being dominated by “nuisance” jellyfish. We question this current paradigm by presenting a broad overview of gelatinous zooplankton in a historicalcontext to develop the hypothesis that population changes reflect the human-mediated alteration of global ocean ecosystems. To this end, we synthesize information related to the evolutionary context of contemporary gelatinous zooplankton blooms, the human frame of reference forchanges in gelatinous zooplankton populations, and whether sufficient data are available to have established the paradigm. We conclude that the current paradigm in which it is believed that there has been a global increase in gelatinous zooplankton is unsubstantiated, and we develop a strategy for addressing the critical questions about long-term, human-related changes in the sea as they relate to gelatinous zooplankton blooms

    Field Evaluation of the Cepheid GeneXpert Chlamydia trachomatis assay for Detection of Infection in a Trachoma Endemic Community in Tanzania.

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    \ud \ud To determine the sensitivity, specificity, and field utility of the Cepheid GeneXpert Chlamydia trachomatis (CT) Assay (GeneXpert) for ocular chlamydia infection compared to Roche Amplicor CT assay (Amplicor). In a trachoma-endemic community in Kongwa Tanzania, 144 children ages 0 to 9 were surveyed to assess clinical trachoma and had two ocular swabs taken. One swab was processed at Johns Hopkins University, Baltimore MD, using Amplicor, (Roche Molecular Diagnostics) and the other swab was processed at a field station in Kongwa using the GeneXpert Chlamydia trachomatis/Neisseria gonorrhoeae assay (Cepheid). The sensitivity and specificity of GeneXpert was compared to the Amplicor assay. Of the 144 swabs taken the prevalence of follicular trachoma by clinical exam was 43.7%, and by evidence of infection according to Amplicor was 28.5%. A total of 17 specimens (11.8%) could not be processed by GeneXpert in the field due to lack of sample volume, other specimen issues or electricity failure. The sensitivity of GeneXpert when compared to Amplicor was 100% and the specificity was 95%. The GeneXpert test identified more positives in individuals with clinical trachoma than Amplicor, 55% versus 52%. The GeneXpert test for C. trachomatis performed with high sensitivity and specificity and demonstrated excellent promise as a field test for trachoma control.\u

    Identification of d -arabinan-degrading enzymes in mycobacteria

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    Bacterial cell growth and division require the coordinated action of enzymes that synthesize and degrade cell wall polymers. Here, we identify enzymes that cleave the D-arabinan core of arabinogalactan, an unusual component of the cell wall of Mycobacterium tuberculosis and other mycobacteria. We screened 14 human gut-derived Bacteroidetes for arabinogalactan-degrading activities and identified four families of glycoside hydrolases with activity against the D-arabinan or D-galactan components of arabinogalactan. Using one of these isolates with exo-D-galactofuranosidase activity, we generated enriched D-arabinan and used it to identify a strain of Dysgonomonas gadei as a D-arabinan degrader. This enabled the discovery of endo- and exo-acting enzymes that cleave D-arabinan, including members of the DUF2961 family (GH172) and a family of glycoside hydrolases (DUF4185/GH183) that display endo-D-arabinofuranase activity and are conserved in mycobacteria and other microbes. Mycobacterial genomes encode two conserved endo-D-arabinanases with different preferences for the D-arabinan-containing cell wall components arabinogalactan and lipoarabinomannan, suggesting they are important for cell wall modification and/or degradation. The discovery of these enzymes will support future studies into the structure and function of the mycobacterial cell wall

    Regional block versus general anaesthesia for caesarean section and neonatal outcomes: a population-based study

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    <p>Abstract</p> <p>Background</p> <p>Anaesthesia guidelines recommend regional anaesthesia for most caesarean sections due to the risk of failed intubation and aspiration with general anaesthesia. However, general anaesthesia is considered to be safe for the foetus, based on limited evidence, and is still used for caesarean sections.</p> <p>Methods</p> <p>Cohorts of caesarean sections by indication (that is, planned repeat caesarean section, failure to progress, foetal distress) were selected from the period 1998 to 2004 (<it>N </it>= 50,806). Deliveries performed under general anaesthesia were compared with those performed under spinal or epidural, for the outcomes of neonatal intubation and 5-minute Apgar (Apgar5) <7.</p> <p>Results</p> <p>The risk of adverse outcomes was increased for caesarean sections under general anaesthesia for all three indications and across all levels of hospital. The relative risks were largest for low-risk planned repeat caesarean deliveries: resuscitation with intubation relative risk was 12.8 (95% confidence interval 7.6, 21.7), and Apgar5 <7 relative risk was 13.4 (95% confidence interval 9.2, 19.4). The largest absolute increase in risk was for unplanned caesareans due to foetal distress: there were five extra intubations per 100 deliveries and six extra Apgar5 <7 per 100 deliveries.</p> <p>Conclusion</p> <p>The infants most affected by general anaesthesia were those already compromised <it>in utero</it>, as evidenced by foetal distress. The increased rate of adverse neonatal outcomes should be weighed up when general anaesthesia is under consideration.</p
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