4,361 research outputs found

    Visual Analytics: Computational AND Representational Data Processing to Support Analytic Rigor

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    Effects of increasing dietary zinc sulfate fed to gestating ewes: II. Milk somatic cell count, microbial populations, and fatty acid composition

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    Objective: The objective of the research was to evaluate the effects of increasing dietary Zn sulfate concentration for primiparous gestating ewes on subsequent milk SCC, intramammary microbial identifications, and fatty acid composition. Materials and Methods: Commercial white-face (WF; n = 27) and black-face (BF; n = 24) ewes (age ≈18 mo; BW = 87.48 ± 8.37 kg) were sorted into breed-type groups and within groups ranked by BW, and then, they were randomly divided into 3 dietary supplement treatment groups: CON (n = 13; 40 mg/kg Zn; ≈1 × NASEM recommendations), Zn500 (n = 21; 500 mg/kg Zn; ≈4 × NASEM recommendations), and Zn1000 (n = 17; 1,000 mg/kg Zn; ≈7 × NASEM recommendations). Treatments were administered in Zn-fortified pelleted alfalfa (0.45 kg/ewe per day) and fed from 87.5 ± 8.9 d of gestation until parturition. Milk traits collected at parturition (d 1 of lactation), ≈30 d of lactation, and lamb weaning (≈90 d of lactation) were assessed as repeated measures with fixed effects of treatment, breed type, and litter size. Results and Discussion: The treatment × breed type interaction affected ewe logSCC (P = 0.01), and within Zn500, BF had greater logSCC than WF ewes (5.90 ± 0.08 vs. 5.46 ± 0.08; P \u3c 0.01). However, breed types did not differ between CON and Zn1000 treatments (P ≄ 0.92). Ewe logSCC was greatest (P \u3c 0.01) at weaning (6.03 ± 0.06), intermediate at parturition (5.72 ± 0.06; d 1), and least at d 30 of lactation (5.21 ± 0.06). Intramammary infections were common in milk samples collected at parturition (77%) and weaning (47%) based on culture-based microbial identifications. The most frequently identified species included Bacillus spp. and Staphylococcus spp. Black-face ewes had greater concentrations of C16:1 (1.78 mg/100 vs. 1.39 mg/100 mg of fatty acid per 100 mg of total fatty acids), C17:1 (0.86 mg/100 vs. 0.76 mg/100 mg of fatty acid per 100 mg of total fatty acids), and C20:4 (0.28 mg/100 vs. 0.24 mg/100 mg of fatty acid per 100 mg of total fatty acids; P ≀ 0.04) than WF ewes. Implications and Applications: Including Zn in diets beyond NASEM recommendations from mid to late gestation had no effect on ewe milk SCC, microbial pathogens identified, or fatty acid composition. However, findings indicated there may be important breed differences in dietary Zn utilization and requirements affecting intramammary inflammation

    Does lower-limb osteoarthritis alter motor cortex descending drive and voluntary activation? A systematic review and meta-analysis

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    Purpose: The aim of the study was to quantify motor cortex descending drive and voluntary activation (VA) in people with lower-limb OA compared to controls. Methods: A systematic review and meta-analysis according to the PRISMA guidelines was carried out. Seven databases were searched until 30 December 2022. Studies assessing VA or responses to transcranial magnetic stimulation (TMS; i.e. motor evoked potential, intracortical facilitation, motor threshold, short-interval intracortical inhibition, and silent period) were included. Study quality was assessed using Joanna Briggs Institute criteria and evidence certainty using GRADE. The meta-analysis was performed using RevMan inverse variance, mixed-effect models. Results: Eighteen studies were included, all deemed low-quality. Quadriceps VA was impaired with knee OA compared to healthy controls (standardised mean difference (SMD)=0.84, 95% CI=−1.12–0.56, low certainty). VA of the more symptomatic limb was impaired (SMD=0.42, 95% CI=−0.75–0.09, moderate certainty) compared to the other limb in people with hip/knee OA. As only two studies assessed responses to TMS, very low-certainty evidence demonstrated no significant difference between knee OA and healthy controls for motor evoked potential, intracortical facilitation, resting motor threshold or short-interval intracortical inhibition. Conclusions: Low-certainty evidence suggests people with knee OA have substantial impairments in VA of their quadriceps muscle when compared to healthy controls. With moderate certainty we conclude that people with hip and knee OA had larger impairments in VA of the quadriceps in their more painful limb compared to their non-affected/other limb

    Relationships among intramammary health, udder and teat characteristics, and productivity of extensively managed ewes

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    Mastitis is an economically important disease and its subclinical state is difficult to diagnose, which makes mitigation more challenging. The objectives of this study were to screen clinically healthy ewes in order to 1) identify cultivable microbial species in milk, 2) evaluate somatic cell count (SCC) thresholds associated with intramammary infection, and 3) estimate relationships between udder and teat morphometric traits, SCC, and ewe productivity. Milk was collected from two flocks in early (\u3c5 \u3ed) and peak (30 to 45 d) lactation to quantify SCC (n = 530) and numerate cultivable microbial species by culture-based isolation followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS; n = 243) identification. Within flock and lactation stage, 11% to 74% (mean = 36%) of samples were culture positive. More than 50 unique identifications were classified by MALDI-TOF MS analysis, and Bacillus licheniformis (18% to 27%), Micrococcus flavus (25%), Bacillus amyloliquefaciens (7% to 18%), and Staphylococcus epidermidis (26%) were among the most common within flock and across lactation stage. Optimum SCC thresholds to identify culture-positive samples ranged from 175 × 103 to 1,675 × 103 cells/mL. Ewe productivity was assessed as total 120-d adjusted litter weight (LW120) and analyzed within flock with breed, parity, year, and the linear covariate of log10 SCC (LSCC) at early or peak lactation. Although dependent on lactation stage and year, each 1-unit increase in LSCC (e.g., an increase in SCC from 100 × 103 to 1,000 × 103 cells/mL) was predicted to decrease LW120 between 9.5 and 16.1 kg when significant. Udder and teat traits included udder circumference, teat length, teat placement, and degree of separation of the udder halves. Correlations between traits were generally low to moderate within and across lactation stage and most were not consistently predictive of ewe LSCC. Overall, the frequencies of bacteria-positive milk samples indicated that subclinical mastitis (SCM) is common in these flocks and can impact ewe productivity. Therefore, future research is warranted to investigate pathways and timing of microbial invasion, genomic regions associated with susceptibility, and husbandry to mitigate the impact of SCM in extensively managed ewes

    CRATES: An All-Sky Survey of Flat-Spectrum Radio Sources

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    We have assembled an 8.4 GHz survey of bright, flat-spectrum (alpha > -0.5) radio sources with nearly uniform extragalactic (|b|>10 deg) coverage for sources brighter than S_{4.8 GHz} = 65 mJy. The catalog is assembled from existing observations (especially CLASS and the Wright et al. PMN-CA survey), augmented by reprocessing of archival VLA and ATCA data and by new observations to fill in coverage gaps. We refer to this program as CRATES, the Combined Radio All-sky Targeted Eight GHz Survey. The resulting catalog provides precise positions, sub-arcsecond structures, and spectral indices for some 11,000 sources. We describe the morphology and spectral index distribution of the sample and comment on the survey's power to select several classes of interesting sources, especially high energy blazars. Comparison of CRATES with other high-frequency surveys also provides unique opportunities for identification of high-power radio sources.Comment: 23 pages, 7 figures, 2 machine-readable tables available at http://astro.stanford.edu/CRATES/ ; accepted for publication in ApJ

    A Wormhole at the core of an infinite cosmic string

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    We study a solution of Einstein's equations that describes a straight cosmic string with a variable angular deficit, starting with a 2π2 \pi deficit at the core. We show that the coordinate singularity associated to this defect can be interpreted as a traversible wormhole lodging at the the core of the string. A negative energy density gradually decreases the angular deficit as the distance from the core increases, ending, at radial infinity, in a Minkowski spacetime. The negative energy density can be confined to a small transversal section of the string by gluing to it an exterior Gott's like solution, that freezes the angular deficit existing at the matching border. The equation of state of the string is such that any massive particle may stay at rest anywhere in this spacetime. In this sense this is 2+1 spacetime solution.Comment: 1 tex file and 5 eps files. To be Published in Nov. in Phys.Rev.

    A framework for power analysis using a structural equation modelling procedure

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    BACKGROUND: This paper demonstrates how structural equation modelling (SEM) can be used as a tool to aid in carrying out power analyses. For many complex multivariate designs that are increasingly being employed, power analyses can be difficult to carry out, because the software available lacks sufficient flexibility. Satorra and Saris developed a method for estimating the power of the likelihood ratio test for structural equation models. Whilst the Satorra and Saris approach is familiar to researchers who use the structural equation modelling approach, it is less well known amongst other researchers. The SEM approach can be equivalent to other multivariate statistical tests, and therefore the Satorra and Saris approach to power analysis can be used. METHODS: The covariance matrix, along with a vector of means, relating to the alternative hypothesis is generated. This represents the hypothesised population effects. A model (representing the null hypothesis) is then tested in a structural equation model, using the population parameters as input. An analysis based on the chi-square of this model can provide estimates of the sample size required for different levels of power to reject the null hypothesis. CONCLUSIONS: The SEM based power analysis approach may prove useful for researchers designing research in the health and medical spheres
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