1,811 research outputs found

    Utilising the concept of nutrients as a currency within organic farming system

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    This report was presented at the UK Organic Research 2002 Conference.Within organic systems, the successful management of nutrients at the field level is crucial for maximising production and minimising the environmental impacts. This requires that the farmer makes the best possible use of nutrients excreted by the grazing or housed livestock. In addition, the farmer must successfully manage the nutrients built-up in the ley phase of the crop rotation over the whole of the arable phase period. To analyse these complex flows, a nutrient budget model has been developed that describes the spatial and temporal flows within the organic farming system. The concept is analogous to treating nutrients as a currency where the flow of nutrients represents a cashflow. A spatial nutrient budget permits the analyses of the performance of the nutrient flows to be examined for the housing, manure, livestock, rotational land and permanent pasture to be analysed separately. This analysis will allow the farmer to better understand the weaknesses in the system, and hence take preventative measures

    A Guide to Nutrient Budgeting on Organic Farms

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    The leaflet gives practical guidance on using data and calculating farm-gate nutrient budgets with sections on soil analysis, nutrient inputs, nutrient losses and flows, nitrogen fixation through leys and how inputs and outputs from organic manures and livestock feed can be recorded. It contains one example table of a farm-gate annual nutrient budget for a mixed cattle and arable farm. The tool is specific to organic farming. It was drafted for the UK but has relevance in other countries

    Autoantigens in Vitiligo Identified by the Serological Selection of a Phage-Displayed Melanocyte cDNA Expression Library

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    Vitiligo is an acquired idiopathic hypomelanotic disorder characterized by circumscribed depigmented macules resulting from the loss of cutaneous melanocytes. Although the exact cause of vitiligo remains obscure, autoimmunity may play a role in the development of the disease. The present study was undertaken to investigate the applicability of phage display technology to identify B-cell autoantigens in vitiligo. A melanocyte cDNA phage display library was subjected to rounds of enrichment with vitiligo patient IgG. Subsequently, enriched IgG-binding peptides representing putative autoantigens were identified by sequencing their encoding cDNAs. Radioimmunoassays were used to confirm the immunoreactivity of vitiligo patient (n=61) and control (n=28) sera to several of the putative autoantigens. Non-segmental vitiligo patient sera (n=53) were positive for antibody (Ab) reactivity to gamma-enolase (8%); alpha-enolase (9%); heat-shock protein 90 (13%); osteopontin (4%); ubiquitin-conjugating enzyme (15%); translation-initiation factor 2 (6%); and GTP-binding protein, Rab38 (15%). Ab reactivity to at least one of the previously unknown autoantigens was detected in 51% of patients with non-segmental vitiligo. In contrast, Ab reactivity in a group of patients with segmental vitiligo (n=8) was not demonstrated. Overall, the study indicated that the targets of autoantibodies in vitiligo patients can be revealed by employing the methodology of phage display

    Internet Legal Research Program Materials

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    Internet Legal Research presentations include: Google and Beyond: Finding Information Using Search Engines, and Evaluating Your Results; Why Pay For It Twice? How to Access Federal Materials in the Public Domaind; All Politics are Local: State and Local Resources; L is for Lawyer: An Alphabet of Handy Web Pages; Internet Basics: The Who, What, When, Where, Why and How of Internet Research for Lawyers; But Can I Get it in English? Finding Foreign Law; Blawgs, Podcasts, Wikis? Deciphering the Lingo and Evaluating Current Awareness Tool

    Chimpanzees demonstrate individual differences in social information use

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    Studies of transmission biases in social learning have greatly informed our understanding of how behaviour patterns may diffuse through animal populations, yet within-species inter-individual variation in social information use has received little attention and remains poorly understood. We have addressed this question by examining individual performances across multiple experiments with the same population of primates. We compiled a dataset spanning 16 social learning studies (26 experimental conditions) carried out at the same study site over a 12-year period, incorporating a total of 167 chimpanzees. We applied a binary scoring system to code each participant’s performance in each study according to whether they demonstrated evidence of using social information from conspecifics to solve the experimental task or not (Social Information Score—‘SIS’). Bayesian binomial mixed effects models were then used to estimate the extent to which individual differences influenced SIS, together with any effects of sex, rearing history, age, prior involvement in research and task type on SIS. An estimate of repeatability found that approximately half of the variance in SIS was accounted for by individual identity, indicating that individual differences play a critical role in the social learning behaviour of chimpanzees. According to the model that best fit the data, females were, depending on their rearing history, 15–24% more likely to use social information to solve experimental tasks than males. However, there was no strong evidence of an effect of age or research experience, and pedigree records indicated that SIS was not a strongly heritable trait. Our study offers a novel, transferable method for the study of individual differences in social learning

    Analysis of knockout mice suggests a role for VGF in the control of fat storage and energy expenditure

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    <p>Abstract</p> <p>Background</p> <p>Previous studies of mixed background mice have demonstrated that targeted deletion of <it>Vgf </it>produces a lean, hypermetabolic mouse that is resistant to diet-, lesion-, and genetically-induced obesity. To investigate potential mechanism(s) and site(s) of action of VGF, a neuronal and endocrine secreted protein and neuropeptide precursor, we further analyzed the metabolic phenotypes of two independent VGF knockout lines on C57Bl6 backgrounds.</p> <p>Results</p> <p>Unlike hyperactive VGF knockout mice on a mixed C57Bl6-129/SvJ background, homozygous mutant mice on a C57Bl6 background were hypermetabolic with similar locomotor activity levels to <it>Vgf+/Vgf+ </it>mice, during day and night cycles, indicating that mechanism(s) other than hyperactivity were responsible for their increased energy expenditure. In <it>Vgf-/Vgf- </it>knockout mice, morphological analysis of brown and white adipose tissues (BAT and WAT) indicated decreased fat storage in both tissues, and decreased adipocyte perimeter and area in WAT. Changes in gene expression measured by real-time RT-PCR were consistent with increased fatty acid oxidation and uptake in BAT, and increased lipolysis, decreased lipogenesis, and brown adipocyte differentiation in WAT, suggesting that increased sympathetic nervous system activity in <it>Vgf-/Vgf- </it>mice may be associated with or responsible for alterations in energy expenditure and fat storage. In addition, uncoupling protein 1 (UCP1) and UCP2 protein levels, mitochondrial number, and mitochondrial cristae density were upregulated in <it>Vgf-/Vgf- </it>BAT. Using immunohistochemical and histochemical techniques, we detected VGF in nerve fibers innervating BAT and <it>Vgf </it>promoter-driven reporter expression in cervical and thoracic spinal ganglia that project to and innervate the chest wall and tissues including BAT. Moreover, VGF peptide levels were quantified by radioimmunoassay in BAT, and were found to be down-regulated by a high fat diet. Lastly, despite being hypermetabolic, VGF knockout mice were cold intolerant.</p> <p>Conclusion</p> <p>We propose that VGF and/or VGF-derived peptides modulate sympathetic outflow pathways to regulate fat storage and energy expenditure.</p

    Lyplal1 is dispensable for normal fat deposition in mice.

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    Genome-wide association studies (GWAS) have detected association between variants in or near the Lysophospholipase-like 1 (LYPLAL1) locus and metabolic traits, including central obesity, fatty liver and waist-to-hip ratio. LYPLAL1 is also known to be upregulated in the adipose tissue of obese patients. However, the physiological role of LYPLAL1 is not understood. To investigate the function of Lyplal1 in vivo we investigated the phenotype of the Lyplal1tm1a(KOMP)Wtsi homozygous mouse. Body composition was unaltered in Lyplal1 knockout mice as assessed by dual-energy X-ray absorptiometry (DEXA) scanning, both on normal chow and on a high-fat diet. Adipose tissue distribution between visceral and subcutaneous fat depots was unaltered, with no change in adipocyte cell size. The response to both insulin and glucose dosing was normal in Lyplal1tm1a(KOMP)Wtsi homozygous mice, with normal fasting blood glucose concentrations. RNAseq analysis of liver, muscle and adipose tissue confirmed that Lyplal1 expression was ablated with minimal additional changes in gene expression. These results suggest that Lyplal1 is dispensable for normal mouse metabolic physiology and that despite having been maintained through evolution Lyplal1 is not an essential gene, suggesting possible functional redundancy. Further studies will be required to clarify its physiological role

    Soil health metrics reflect yields in long-term cropping system experiments

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    Soil health metrics with strong links to ecological function and agricultural productivity are needed to ensure that future management of agricultural systems meets sustainability goals. While ecological metrics and crop yields are often considered separately from one another, our work sought to assess the links between the two in an agricultural context where productivity is a key consideration. Here, we investigated the value of soil health tests in terms of their relevance to agricultural management practices and crop yields at contrasting long term cropping systems experiments. One site was on a sandy loam Leptic Podzol and the other on a sandy clay loam Endostagnic Luvisol. Furthermore, the experiments had different management systems. One contained legume-supported rotations with different grass-clover ley durations and organic amendment usage, while the other compared a range of nutrient input options through fertiliser and organic amendments on the same rotation without ley periods. Metrics included field tests (earthworm counts and visual evaluation of soil structure scores) with laboratory analysis of soil structure, chemistry and biology. This analysis included bulk density, macroporosity, pH, available phosphorus, exchangeable potassium, soil organic matter and potentially mineralizable nitrogen. Using a novel combination of long-term experiments, management systems and distinctive soil types, we demonstrated that as well as providing nutrients, agricultural management which resulted in better soil organic matter, pH, potassium and bulk density was correlated with higher crop yields. The importance of ley duration and potentially mineralizable nitrogen to yield in legume-supported systems showed the impact of agricultural management on soil biology. In systems with applications of synthetic fertiliser, earthworm counts and visual evaluation of soil structure scores were correlated with higher yields. We concluded that agricultural management altered yields not just through direct supply of nutrients to crops, but also through the changes in soil health measured by simple metrics
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