2,969 research outputs found

    ECONOMIC ANALYSIS OF PHOSPHORUS - REDUCING TECHNOLOGIES IN PORK PRODUCTION

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    Soil phosphorus levels have increased as pork production has become concentrated. Phosphorus-based manure management regulations for land application have been proposed by policy makers. The objective of this study is to determine benefits/costs of adopting two alternatives for reducing phosphorus: synthetic amino acids or phytase. An optimization model is constructed to determine optimal excreted nitrogen and phosphorus from alternative feed ingredients. Results are derived using different manure storage and application systems. While the two alternatives are not least-cost ingredients, they become profitable when producers are constrained by land. An important result is that the net cost of manure is negative.Livestock Production/Industries,

    NUTRITION AND THE ECONOMICS OF SWINE MANAGEMENT

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    Current methods of formulating animal rations lead to excess nutrient excretion which can potentially lead to excess manure nutrients and an increase in economic costs. These methods do not recognize the impact of diminishing returns. The objective is to simultaneously optimize feed ration composition and replacement. The results, when compared against results from a survey of feed companies, indicate that using a profit maximization rather than live weight growth maximization criterion targets nutrients to an animal's actual needs and, hence, fewer nutrients are excreted and higher returns for producers are obtained.nonlinear growth modeling, pigs, replacement, swine, Livestock Production/Industries,

    (-)-Oleocanthal rapidly and selectively induces cancer cell death via lysosomal membrane permeabilization

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    (-)-Oleocanthal (OC), a phenolic compound present in extra-virgin olive oil (EVOO), has been implicated in the health benefits associated with diets rich in EVOO. We investigated the effect of OC on human cancer cell lines in culture and found that OC induced cell death in all cancer cells examined as rapidly as 30 minutes after treatment in the absence of serum. OC treatment of non-transformed cells suppressed their proliferation but did not cause cell death. OC induced both primary necrotic and apoptotic cell death via induction of lysosomal membrane permeabilization (LMP). We provide evidence that OC promotes LMP by inhibiting acid sphingomyelinase (ASM) activity, which destabilizes the interaction between proteins required for lysosomal membrane stability. The data presented here indicate that cancer cells, which tend to have fragile lysosomal membranes compared to non-cancerous cells, are susceptible to cell death induced by lysosomotropic agents. Therefore, targeting lysosomal membrane stability represents a novel approach for the induction of cancer-specific cell death

    Productivity Growth and Convergence in Crop, Ruminant and Non-Ruminant Production: Measurement and Forecasts

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    There is considerable interest in projections of future productivity growth in agriculture. Whether one is interested in the outlook for global commodity markets, future patterns of international trade, or the interactions between land use, deforestation and ecological diversity, the rate of productivity growth in agriculture is an essential input. Yet solid projections for this variable have proven elusive particularly on a global basis. This is due, in no small part, to the difficulty in measuring historical productivity growth. The purpose of this paper is to report the latest time series evidence on total factor productivity growth for crops, ruminants and non-ruminant livestock, on a global basis. We then follow with tests for convergence amongst regions, providing forecasts for farm productivity growth to the year 2040. The results suggest that most regions in the sample are likely to experience larger productivity gains in livestock than in crops. Within livestock, the non-ruminant sector is expected to continue to be more dynamic than the ruminant sector. Given the rapid rates of productivity growth observed recently, non-ruminant and crop productivity in developing countries may be converging to the productivity levels of developed countries. For ruminants, the results show that productivity levels may be diverging between developed and developing countries.Malmquist index, productivity, convergence, projections, crops, livestock, Productivity Analysis, D24, O13, O47, Q10,

    The New Economics of Livestock Production Management

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    The importance of heterogeneity of animal attributes in livestock production is assessed. Preliminary results indicate that variance and skew measures of attributes may be becoming more important over time.livestock economics, herd management, livestock marketing, Livestock Production/Industries, Marketing,

    The relationship between active travel to school and health-related fitness in children and adolescents: a systematic review

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    Background: Active travel to school (ATS) has been identified as an important source of physical activity for youth. However, the relationship between ATS and health-related fitness (HRF) among youth remains unclear. Methods: A systematic search of seven electronic databases (EMBASE, OVID MEDLINE, PsycINFO, PubMed, Scopus, SPORTDiscus and TRIS on line) was conducted in December 2009 and studies published since 1980 were considered for inclusion. Results: Twenty seven articles were identified that explored the relationship between ATS and the following aspects of HRF: weight status/body composition, cardiorespiratory fitness, muscular fitness and flexibility. Forty-eight percent of the studies that examined the relationship between ATS and weight status/body composition reported significant associations, this increased to 55% once poor quality studies were removed. Furthermore, the findings from five studies, including one longitudinal study, indicate that ATS is positively associated with cardiorespiratory fitness in youth. However, the evidence for the relationships between ATS and muscular fitness or flexibility is equivocal and limited by low study numbers. Conclusions: There is some evidence to suggest that ATS is associated with a healthier body composition and level of cardiorespiratory fitness among youth. Strategies to increase ATS are warranted and should be included in whole-of-school approaches to the promotion of physical activity

    Insensitivity of alkenone carbon isotopes to atmospheric CO<sub>2</sub> at low to moderate CO<sub>2</sub> levels

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    Atmospheric pCO2 is a critical component of the global carbon system and is considered to be the major control of Earth’s past, present and future climate. Accurate and precise reconstructions of its concentration through geological time are, therefore, crucial to our understanding of the Earth system. Ice core records document pCO2 for the past 800 kyrs, but at no point during this interval were CO2 levels higher than today. Interpretation of older pCO2 has been hampered by discrepancies during some time intervals between two of the main ocean-based proxy methods used to reconstruct pCO2: the carbon isotope fractionation that occurs during photosynthesis as recorded by haptophyte biomarkers (alkenones) and the boron isotope composition (δ11B) of foraminifer shells. Here we present alkenone and δ11B-based pCO2 reconstructions generated from the same samples from the Plio-Pleistocene at ODP Site 999 across a glacial-interglacial cycle. We find a muted response to pCO2 in the alkenone record compared to contemporaneous ice core and δ11B records, suggesting caution in the interpretation of alkenone-based records at low pCO2 levels. This is possibly caused by the physiology of CO2 uptake in the haptophytes. Our new understanding resolves some of the inconsistencies between the proxies and highlights that caution may be required when interpreting alkenone-based reconstructions of pCO2
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