173 research outputs found

    Limit-feeding a high-concentrate diet may alter nutrient absorption

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    Feeding newly arrived cattle is commonly characterized by a few days of feeding longstemmed hay followed by a series of step-up diets, wherein concentrate levels are increased to promote ruminal adaptation to a highconcentrate finishing diet. This is done to give the rumen microbes time to adjust to larger amounts of readily fermentable starches in cereal grains. Rumen epithelial adaptation may be achievable by limit-feeding a finishing diet, with gradual increases in feed intake, until the cattle are on full feed. If this can be achieved without causing ruminal disorders and days off feed, then the cost of feeding cattle can be reduced. By limit-feeding, the higher roughage step-up diets are replaced with a single high-concentrate diet. The cost of grain is less than that of roughage, and there are decreased costs in terms of storage space, waste disposal (due to decreased manure production), and mixing and hauling of rations. The purpose of this experiment was to examine the effects of a traditional step-up program versus a limit-fed finishing diet in terms of dry matter intake, acetate to propionate ratio, and ruminal dilution rate. Diet effects on volatile fatty acid concentration and absorption were also examined by using valerate as a marker for volatile fatty acid absorption

    Safety Outcomes and Near-Adult Height Gain of Growth Hormone-Treated Children with SHOX Deficiency: Data from an Observational Study and a Clinical Trial

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    Background/Aims: To assess auxological and safety data for growth hormone (GH)-Treated children with SHOX deficiency. Methods: Data were examined for GH-Treated SHOX-deficient children (n = 521) from the observational Genetics and Neuroendocrinology of Short Stature International Study (GeNeSIS). For patients with near-Adult height information, GeNeSIS results (n = 90) were compared with a clinical trial (n = 28) of SHOX-deficient patients. Near-Adult height was expressed as standard deviation score (SDS) for chronological age, potentially increasing the observed effect of treatment. Results: Most SHOX-deficient patients in GeNeSIS had diagnoses of Leri-Weill syndrome (n = 292) or non-syndromic short stature (n = 228). For GeNeSIS patients with near-Adult height data, mean age at GH treatment start was 11.0 years, treatment duration 4.4 years, and height SDS gain 0.83 (95% confidence interval 0.49-1.17). Respective ages, GH treatment durations and height SDS gains for GeNeSIS patients prepubertal at baseline (n = 42) were 9.2 years, 6.0 years and 1.19 (0.76-1.62), and for the clinical trial cohort they were 9.2 years, 6.0 years and 1.25 (0.92-1.58). No new GH-related safety concerns were identified. Conclusion: Patients with SHOX deficiency who had started GH treatment before puberty in routine clinical practice had a similar height gain to that of patients in the clinical trial on which approval for the indication was based, with no new safety concerns

    A critical comparison of integral projection and matrix projection models for demographic analysis

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    Structured demographic models are among the most common and useful tools in population biology. However, the introduction of integral projection models (IPMs) has caused a profound shift in the way many demographic models are conceptualized. Some researchers have argued that IPMs, by explicitly representing demographic processes as continuous functions of state variables such as size, are more statistically efficient, biologically realistic, and accurate than classic matrix projection models, calling into question the usefulness of the many studies based on matrix models. Here, we evaluate how IPMs and matrix models differ, as well as the extent to which these differences matter for estimation of key model outputs, including population growth rates, sensitivity patterns, and life spans. First, we detail the steps in constructing and using each type of model. Second, we present a review of published demographic models, concentrating on size-based studies, which shows significant overlap in the way IPMs and matrix models are constructed and analyzed. Third, to assess the impact of various modeling decisions on demographic predictions, we ran a series of simulations based on size-based demographic data sets for five biologically diverse species. We found little evidence that discrete vital rate estimation is less accurate than continuous functions across a wide range of sample sizes or size classes (equivalently bin numbers or mesh points). Most model outputs quickly converged with modest class numbers (≄10), regardless of most other modeling decisions. Another surprising result was that the most commonly used method to discretize growth rates for IPM analyses can introduce substantial error into model outputs. Finally, we show that empirical sample sizes generally matter more than modeling approach for the accuracy of demographic outputs. Based on these results, we provide specific recommendations to those constructing and evaluating structured population models. Both our literature review and simulations question the treatment of IPMs as a clearly distinct modeling approach or one that is inherently more accurate than classic matrix models. Importantly, this suggests that matrix models, representing the vast majority of past demographic analyses available for comparative and conservation work, continue to be useful and important sources of demographic information.Support for this work was provided by NSF awards 1146489, 1242558, 1242355, 1353781, 1340024, 1753980, and 1753954, 1144807, 0841423, and 1144083. Support also came from USDA NIFA Postdoctoral Fellowship (award no. 2019-67012-29726/project accession no. 1019364) for R. K. Shriver; the Swiss Polar Institute of Food and Agriculture for N. I. Chardon; the ICREA under the ICREA Academia Programme for C. Linares; and SERDP contract RC-2512 and USDA National Institute of Food and Agriculture, Hatch project 1016746 for A .M. Louthan. This is Contribution no. 21-177-J from the Kansas Agricultural Experiment Station

    On Viable Service Systems: Developing a Modeling Framework for Analysis of Viability in Service Systems

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    This paper explores the contribution of systems modeling to the design and analysis of viability in service systems. We apply a modeling framework called SEAM (Systemic Enterprise Architecture Method) to gain an understanding of how a service system maintains its identity and remains viable in its environment. SEAM embodies theoretical insights from systems science and organizational cybernetics, in particular the viable system model of Stafford Beer. We illustrate the applicability of the framework by modeling the design of viability in a service system

    E-cigarettes and urologic health: a collaborative review of toxicology, epidemiology, and potential risks

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    Context: Use of electronic cigarettes (ECs) is on the rise in most high-income countries. Smoking conventional cigarettes is a known risk factor for urologic malignancy incidence, progression, and mortality, as well as for other urologic health indicators. The potential impact of EC use on urologic health is therefore of clinical interest to the urology community. Objective: To review the available data on current EC use, including potential benefits in urologic patients, potential issues linked to toxicology of EC constituents, and how this might translate into urologic health risks. Evidence acquisition: A Medline search was carried out in August 2016 for studies reporting urologic health outcomes and EC use. Snowballing techniques were also used to identify relevant studies from recent systematic reviews. A narrative synthesis of data around EC health outcomes, toxicology, and potential use in smoking cessation and health policy was carried out. Evidence synthesis: We found no studies to date that have been specifically designed to prospectively assess urologic health risks, even in an observational setting. Generating such data would be an important contribution to the debate on the role of ECs in public health and clinical practice. There is evidence from a recent Cochrane review of RCTs that ECs can support smoking cessation. There are emerging data indicating that potentially harmful components of ECs such as tobacco-specific nitrosamines, polyaromatic hydrocarbons, and heavy metals could be linked to possible urologic health risks. Conclusions: ECs might be a useful tool to encourage cessation of conventional cigarette smoking. However, data collection around the specific impact of ECs on urologic health is needed to clarify the possible patient benefits, outcomes, and adverse events. Patient summary: While electronic cigarettes might help some people to stop smoking, their overall impact on urologic health is not clear. While electronic cigarettes might help some people to stop smoking, it is not clear if they may be bad for urologic health

    TOI-1268b: The youngest hot Saturn-mass transiting exoplanet

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    We report the discovery of TOI-1268b, a transiting Saturn-mass planet from the TESS space mission. With an age of less than 1 Gyr, derived from various age indicators, TOI-1268b is the youngest Saturn-mass planet known to date; it contributes to the small sample of well-characterised young planets. It has an orbital period of P = 8.1577080 \ub1 0.0000044 days, and transits an early K-dwarf star with a mass of M∗ = 0.96 \ub1 0.04 M+, a radius of R∗ = 0.92 \ub1 0.06 R+, an effective temperature of Teff = 5300 \ub1 100 K, and a metallicity of 0.36 \ub1 0.06 dex. By combining TESS photometry with high-resolution spectra acquired with the Tull spectrograph at the McDonald Observatory, and the high-resolution spectrographs at the Tautenburg and OndR ejov Observatories, we measured a planetary mass of Mp = 96.4 \ub1 8.3 Mp and a radius of Rp = 9.1 \ub1 0.6 Rp. TOI-1268 is an ideal system for studying the role of star-planet tidal interactions for non-inflated Saturn-mass planets. We used system parameters derived in this paper to constrain the planeta\u27s tidal quality factor to the range of 104.5-5.3. When compared with the sample of other non-inflated Saturn-mass planets, TOI-1268b is one of the best candidates for transmission spectroscopy studies

    Criteria for evaluation of novel markers of cardiovascular risk: A scientific statement from the American Heart Association

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    There is increasing interest in utilizing novel markers of cardiovascular disease risk, and consequently, there is a need to assess the value of their use. This scientific statement reviews current concepts of risk evaluation and proposes standards for the critical appraisal of risk assessment methods. An adequate evaluation of a novel risk marker requires a sound research design, a representative at-risk population, and an adequate number of outcome events. Studies of a novel marker should report the degree to which it adds to the prognostic information provided by standard risk markers. No single statistical measure provides all the information needed to assess a novel marker, so measures of both discrimination and accuracy should be reported. The clinical value of a marker should be assessed by its effect on patient management and outcomes. In general, a novel risk marker should be evaluated in several phases, including initial proof of concept, prospective validation in independent populations, documentation of incremental information when added to standard risk markers, assessment of effects on patient management and outcomes, and ultimately, cost-effectiveness

    The Polygenic and Monogenic Basis of Blood Traits and Diseases

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    Blood cells play essential roles in human health, underpinning physiological processes such as immunity, oxygen transport, and clotting, which when perturbed cause a significant global health burden. Here we integrate data from UK Biobank and a large-scale international collaborative effort, including data for 563,085 European ancestry participants, and discover 5,106 new genetic variants independently associated with 29 blood cell phenotypes covering a range of variation impacting hematopoiesis. We holistically characterize the genetic architecture of hematopoiesis, assess the relevance of the omnigenic model to blood cell phenotypes, delineate relevant hematopoietic cell states influenced by regulatory genetic variants and gene networks, identify novel splice-altering variants mediating the associations, and assess the polygenic prediction potential for blood traits and clinical disorders at the interface of complex and Mendelian genetics. These results show the power of large-scale blood cell trait GWAS to interrogate clinically meaningful variants across a wide allelic spectrum of human variation. Analysis of blood cell traits in the UK Biobank and other cohorts illuminates the full genetic architecture of hematopoietic phenotypes, with evidence supporting the omnigenic model for complex traits and linking polygenic burden with monogenic blood diseases

    The Polygenic and Monogenic Basis of Blood Traits and Diseases

    Get PDF
    Blood cells play essential roles in human health, underpinning physiological processes such as immunity, oxygen transport, and clotting, which when perturbed cause a significant global health burden. Here we integrate data from UK Biobank and a large-scale international collaborative effort, including data for 563,085 European ancestry participants, and discover 5,106 new genetic variants independently associated with 29 blood cell phenotypes covering a range of variation impacting hematopoiesis. We holistically characterize the genetic architecture of hematopoiesis, assess the relevance of the omnigenic model to blood cell phenotypes, delineate relevant hematopoietic cell states influenced by regulatory genetic variants and gene networks, identify novel splice-altering variants mediating the associations, and assess the polygenic prediction potential for blood traits and clinical disorders at the interface of complex and Mendelian genetics. These results show the power of large-scale blood cell trait GWAS to interrogate clinically meaningful variants across a wide allelic spectrum of human variation.</p
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