3,200 research outputs found

    Growing soybeans in Missouri : a 4-H project

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    University of Missouri College of Agriculture and the United States Department of Agriculture cooperating."February, 1944."Title from cover

    Optimisation of impact pile driving using optical fibre Bragg grating measurements

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    This paper reports the use of optical Fibre Bragg Grating (FBG) sensors to monitor the stress waves generated below ground during pile driving, combined with measurements using conventional pile driving analyzer (PDA) sensors mounted at the pile head. Fourteen tubular steel piles with a diameter of 508 mm and embedded length to diameter ratios of 6 to 20 were impact driven at an established chalk test site in Kent, UK. The pile shafts were instrumented with multiple FBG strain gauges and pile head PDA sensors, which monitored the piles’ responses under each hammer blow. A high frequency (5kHz) fibre optic interrogator allowed a previously unseen resolution of the stress wave propagation along the pile. Estimates of the base soil resistances to driving and distributions of shaft shear resistances were found through signal matching that compared time series of pile head PDA measurements and FBG strains measured below ground surface. Numerical solutions of the onedimensional wave equation were optimised by taking account of the data from multiple FBG gauges, leading to significant advantages that have potential for widespread application in cases where high resolution strain measurements are made

    A Cost Comparison of Treatments of Moderate to Severe Psoriasis

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    This study of the efficacy and cost-effectiveness of moderate to severe psoriasis treatments compared phototherapy, oral systemic agents, and biologics from a managed health care systems perspective. A literature review was conducted to identify published studies reporting Psoriasis Area and Severity Index (PASI) percentage improvement from baseline (PASI%) for selected treatments. The researchers then calculated total annualized costs. For each treatment, annualized cost-effectiveness was calculated by dividing total annualized costs of treatment by PASI%. The costs necessary to achieve clinically meaningful outcomes (PASI50 and PASI75) were then calculated. Of 3886 articles examined, 16 studies met inclusion criteria. Oral systemic medications, UV therapy, and UV therapy combined with acitretin appear to be the most cost-effective therapies for moderate to severe psoriasis

    When Will the Antarctic Ozone Hole Recover?

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    The Antarctic ozone hole demonstrates large-scale, man-made affects on our atmosphere. Surface observations now show that human produced ozone depleting substances (ODSs) are declining. The ozone hole should soon start to diminish because of this decline. Herein we demonstrate an ozone hole parametric model. This model is based upon: 1) a new algorithm for estimating C1 and Br levels over Antarctica and 2) late-spring Antarctic stratospheric temperatures. This parametric model explains 95% of the ozone hole area s variance. We use future ODS levels to predict ozone hole recovery. Full recovery to 1980 levels will occur in approximately 2068. The ozone hole area will very slowly decline over the next 2 decades. Detection of a statistically significant decrease of area will not occur until approximately 2024. We further show that nominal Antarctic stratospheric greenhouse gas forced temperature change should have a small impact on the ozone hole

    Racial/ethnic differences in hepatic steatosis in a population‐based cohort of post‐menopausal women: the Michigan Study of Women's Health Across the Nation

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    Aims The prevalence of hepatic steatosis may differ between post‐menopausal African‐American women and non‐Hispanic white women and by sex hormone binding globulin level. We examined prevalence of hepatic steatosis by race/ethnicity and associations with sex hormone binding globulin. Methods Participants included post‐menopausal women who underwent hepatic ultrasound ( n  = 345) at the Michigan site of the Study of Women's Health Across the Nation, a population‐based study. We examined hepatic steatosis prevalence by race/ethnicity and used logistic regression models to calculate the odds of hepatic steatosis with race/ethnicity and sex hormone binding globulin, after adjustment for age, alcohol use, waist circumference, high density lipoprotein cholesterol, triglycerides, systolic blood pressure and use of medications reported to lower intrahepatic fat. Results Fewer African‐American women than non‐Hispanic white women had hepatic steatosis (23 vs. 36%, P  = 0.01). African‐American women had lower triglyceride and low‐density lipoprotein cholesterol levels, but higher blood pressure and follicle‐stimulating hormone levels ( P  < 0.05). In the optimal‐fitting multivariable models, women in the highest tertile of sex hormone binding globulin (60.2–220.3 nmol/l) had a lower odds of hepatic steatosis (odds ratio 0.43, 95% CI 0.20–0.93) compared with women in the lowest tertile of sex hormone binding globulin (10.5–40.3 nmol/l). There was an interaction between race/ethnicity and medication use whereby non‐Hispanic white women using medications had three times higher odds of hepatic steatosis compared with African‐American women not using medications (odds ratio 3.36, 95%  CI 1.07–10.58). Interactions between race/ethnicity and other variables, including sex hormone levels, were not significant. Conclusions Hepatic steatosis on ultrasound may be more common in post‐menopausal non‐Hispanic white women than African‐American women and was associated with lower levels of sex hormone binding globulin. What's new? Although hepatic steatosis is common in post‐menopausal women, previous studies have not examined risk factors in this population, particularly sex steroids and sex hormone binding globulin. We report that increased sex hormone binding globulin, the primary binding protein of sex hormones and a risk factor for diabetes, was strongly associated with decreased odds of hepatic steatosis in both race/ethnicities.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/101792/1/dme12225.pd

    Persistence of Pathogens with Short Infectious Periods in Seasonal Tick Populations: The Relative Importance of Three Transmission Routes

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    BACKGROUND: The flaviviruses causing tick-borne encephalitis (TBE) persist at low but consistent levels in tick populations, despite short infectious periods in their mammalian hosts and transmission periods constrained by distinctly seasonal tick life cycles. In addition to systemic and vertical transmission, cofeeding transmission has been proposed as an important route for the persistence of TBE-causing viruses. Because cofeeding transmission requires ticks to feed simultaneously, the timing of tick activity may be critical to pathogen persistence. Existing models of tick-borne diseases do not incorporate all transmission routes and tick seasonality. Our aim is to evaluate the influence of seasonality on the relative importance of different transmission routes by using a comprehensive mathematical model. METHODOLOGY/PRINCIPAL FINDINGS: We developed a stage-structured population model that includes tick seasonality and evaluated the relative importance of the transmission routes for pathogens with short infectious periods, in particular Powassan virus (POWV) and the related "deer tick virus," emergent encephalitis-causing flaviviruses in North America. We used the next generation matrix method to calculate the basic reproductive ratio and performed elasticity analyses. We confirmed that cofeeding transmission is critically important for such pathogens to persist in seasonal tick populations over the reasonable range of parameter values. At higher but still plausible rates of vertical transmission, our model suggests that vertical transmission can strongly enhance pathogen prevalence when it operates in combination with cofeeding transmission. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that the consistent prevalence of POWV observed in tick populations could be maintained by a combination of low vertical, intermediate cofeeding and high systemic transmission rates. When vertical transmission is weak, nymphal ticks support integral parts of the transmission cycle that are critical for maintaining the pathogen. We also extended the model to pathogens that cause chronic infections in hosts and found that cofeeding transmission could contribute to elevating prevalence even in these systems. Therefore, the common assumption that cofeeding transmission is not relevant in models of chronic host infection, such as Lyme disease, could lead to underestimating pathogen prevalence

    Simulating Intestinal Transporter and Enzyme Activity in a Physiologically Based Pharmacokinetic Model for Tenofovir Disoproxil Fumarate

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    Tenofovir disoproxil fumarate (TDF), a prodrug of tenofovir, has oral bioavailability (25%) limited by intestinal transport (P-glycoprotein), and intestinal degradation (carboxylesterase). However, the influence of luminal pancreatic enzymes is not fully understood. Physiologically based pharmacokinetic (PBPK) modeling has utility for estimating drug exposure from in vitro data. This study aimed to develop a PBPK model that included luminal enzyme activity to inform dose reduction strategies. TDF and tenofovir stability in porcine pancrelipase concentrations was assessed (0, 0.48, 4.8, 48, and 480 U/ml of lipase; 1 mM TDF; 37°C; 0 to 30 min). Samples were analyzed using mass spectrometry. TDF stability and permeation data allowed calculation of absorption rates within a human PBPK model to predict plasma exposure following 6 days of once-daily dosing with 300 mg of TDF. Regional absorption of drug was simulated across gut segments. TDF was degraded by pancrelipase (half-lives of 0.07 and 0.62 h using 480 and 48 U/ml, respectively). Previously reported maximum concentration (Cmax; 335 ng/ml), time to Cmax (Tmax; 2.4 h), area under the concentration-time curve from 0 to 24 h (AUC0–24; 3,045 ng · h/ml), and concentration at 24 h (C24; 48.3 ng/ml) were all within a 0.5-fold difference from the simulated Cmax (238 ng/ml), Tmax (3 h), AUC0–24 (3,036 ng · h/ml), and C24 (42.7 ng/ml). Simulated TDF absorption was higher in duodenum and jejunum than in ileum (p<0.05). These data support that TDF absorption is limited by the action of intestinal lipases. Our results suggest that bioavailability may be improved by protection of drug from intestinal transporters and enzymes, for example, by coadministration of enzyme-inhibiting agents or nanoformulation strategies

    Response to Thackeray (2016) – The possibility of lichen growth on bones of Homo naledi: Were they exposed to light?

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    Thackeray1 questions the hypothesis of deliberate body disposal in the Rising Star Cave by Homo naledi, as proposed by Dirks and colleagues2. Thackeray proposes that lichens produced mineral staining on the skeletal remains of H. naledi. As lichens require some exposure to light, in Thackeray’s opinion, the presence of mineral staining necessitates either a direct entrance deep into the Rising Star Cave that once admitted light into the Dinaledi Chamber, or relocation of mineral-stained bones from a location exposed to light. Here we consider multiple lines of evidence that reject Thackeray’s hypothesis that lichens deposited mineral staining upon the surface of these skeletal remains. We welcome the opportunity to address the inferences presented by Thackeray, and further hope that this response may dispel misinterpretations of our research2, and of other areas of the scientific literature that bear upon site formation processes at work within the Rising Star Cave system

    Osteopathology and insect traces in the Australopithecus africanus skeleton StW 431

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    We present the first application of high-resolution micro computed tomography in an analysis of both the internal and external morphology of the lumbar region of StW 431 – a hominin skeleton recovered from Member 4 infill of the Sterkfontein Caves (South Africa) in 1987. The lumbar vertebrae of the individual present a number of proliferative and erosive bony processes, which were investigated in this study. Investigations suggest a complex history of taphonomic alteration to pre-existing spinal degenerative joint disease (SDJD) as well as post-mortem modification by an unknown insect. This study is in agreement with previous pathological diagnoses of SDJD which affected StW 431 and is the first time insect traces on this hominin are described. The results of this analysis attest to the complex series of post-mortem processes affecting the Sterkfontein site and its fossil assemblages
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