3,067 research outputs found

    Fuzzy Inference System for VOLT/VAR control in distribution substations in isolated power systems

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    This paper presents a fuzzy inference system for voltage/reactive power control in distribution substations. The purpose is go forward to automation distribution and its implementation in isolated power systems where control capabilities are limited and it is common using the same applications as in continental power systems. This means that lot of functionalities do not apply and computational burden generates high response times. A fuzzy controller, with logic guidelines embedded based upon heuristic rules resulting from operators at dispatch control center past experience, has been designed. Working as an on-line tool, it has been tested under real conditions and it has managed the operation during a whole day in a distribution substation. Within the limits of control capabilities of the system, the controller maintained successfully an acceptable voltage profile, power factor values over 0,98 and it has ostensibly improved the performance given by an optimal power flow based automation system

    Photosynthesis and growth reduction with warming are driven by nonstomatal limitations in a Mediterranean semi-arid shrub

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    Whereas warming enhances plant nutrient status and photosynthesis in most terrestrial ecosystems, dryland vegetation is vulnerable to the likely increases in evapotranspiration and reductions in soil moisture caused by elevated temperatures. Any warming‐induced declines in plant primary production and cover in drylands would increase erosion, land degradation, and desertification. We conducted a four‐year manipulative experiment in a semi‐arid Mediterranean ecosystem to evaluate the impacts of a ~2°C warming on the photosynthesis, transpiration, leaf nutrient status, chlorophyll content, isotopic composition, biomass growth, and postsummer survival of the native shrub Helianthemum squamatum. We predicted that warmed plants would show reduced photosynthetic activity and growth, primarily due to the greater stomatal limitation imposed by faster and more severe soil drying under warming. On average, warming reduced net photosynthetic rates by 36% across the study period. Despite this strong response, warming did not affect stomatal conductance and transpiration. The reduction of peak photosynthetic rates with warming was more pronounced in a drought year than in years with near‐average rainfall (75% and 25–40% reductions relative to controls, respectively), with no indications of photosynthetic acclimation to warming through time. Warmed plants had lower leaf N and P contents, δ (13)C, and sparser and smaller leaves than control plants. Warming reduced shoot dry mass production by 31%. However, warmed plants were able to cope with large reductions in net photosynthesis, leaf area, and shoot biomass production without changes in postsummer survival rates. Our findings highlight the key role of nonstomatal factors (biochemical and/or nutritional) in reducing net carbon assimilation rates and growth under warming, which has important implications for projections of plant carbon balance under the warmer and drier climatic scenario predicted for drylands worldwide. Projected climate warming over the coming decades could reduce net primary production by about one‐third in semi‐arid gypsum shrublands dominated by H. squamatum

    Nonlinear energy transmission in the gap

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    Numerical simulations of the scattering of a linear plane wave incoming onto a nonlinear medium (sine-Gordon) reveals that: i) nonlinearity allows energy transmission in the forbidden band, ii) this nonlinear transmission occurs beyond an energy threshold of the incoming wave, iii) the process begins (at the threshold) with large amplitude breathers, and then energy is generically transmitted both by kink-antikink pairs and breathers.Comment: Latex file, 6 figures, 9 pages, to appear in Physics Letters

    Eliminating Amylase Testing from the Evaluation of Pancreatitis in the Emergency Department

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    Background: Alterations in serum biomarkers have been used to evaluate for pancreatitis in the emergency department (ED). Studies have shown lipase to be as sensitive and more specific than amylase in diagnosing pancreatitis and that amylase plus lipase does not improve accuracy over lipase alone.Objective: To determine effects of interventions to decrease ordering of amylase in the evaluation of pancreatitis.Methods: We conducted a pre- and post-cohort study. The number of amylase and lipase tests ordered in the ED was recorded prior to intervention to establish a baseline. We introduced an educational intervention to order lipase without amylase. A second intervention involved removing amylase from bedside order entry forms. We introduced a third intervention that included deleting amylase from trauma order forms, and decoupling amylase and lipase in the computer ordering system. We recorded the number of lipase and amylase tests in weekly aggregates for comparison to the baseline. Data analysis using students t-test, standard deviation and p values are reported.Results: Before interventions 93% of patients had both tests ordered. Educational interventions resulted in a decrease to 91% (p=0.06) of co-ordering. Further interventions decreased the percentage of patients evaluated with both tests to 14.3%. This translates into a decrease in patient charges of approximately $350,000 a year.Conclusion: Using simple structured interventions in the ED can reduce amylase ordering. Educational programming alone was not effective in significantly decreasing amylase ordering; however, education plus system-based interventions decreased amylase ordering. [West J Emerg Med. 2010; 11(4):344-347.

    The Impact of Opuntia ficus-indica and Other Vegetables on Serum Cholesterol and Triglycerides: A Cross-Sectional Analysis

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    Background: Cholesterol is primarily synthesized in the liver. Treatment with statins and diet regulation are commonly prescribed for people with hypercholesterolemia. Previous claims suggest that the consumption of nopal and other vegetables may have a significant effect on diabetes but scarce is known about its relationship with cholesterol and triglycerides. The aim of this study was to evaluate the impact of nopal and other vegetables on serum cholesterol and triglyceride level in population not related with hypercholesterolemia. Methods: We analyzed a dataset comprising of students from UMAN and their relatives totaling 198 participants. Participants completed an informed consent, filled out questionnaires, anthropometric and serum lipid measurements. A semi-quantitative food questionnaire assessed the frequency and amount of consumption for 56-specific foods. We did a factor analysis with varimax rotation using 7 specific foods we were interested. We conducted linear regression analyses with total cholesterol, LDL-c, and triglycerides as dependent variables. Age, sex, BMI, body fat percentage, and consumption factors (fruits, vegetables, and grains) were included as predictors. Collinearity was assessed using VIF calculations. Results: Approximately 48% of participants consumed nopal on a weekly basis, with most considering their intake to be of median to large amounts, while only 11% reported never consuming nopal. Participants with diabetes showed higher nopal consumption [3.1 (s.e.m. 0.24) vs non-diabetic 2.7 (0.22) vs unknown 1.7 (0.28), p\u3c0.04]. A slight correlation was observed between high self-efficacy in diet and nopal ingestion (rho 0.15, p=0.02), but no significant correlations were found for fruits or grains. Regression analysis revealed that LDL-c was associated with obesity (b=-20, p=0.04) and marginally with body fat percentage (adjusted b=0.83, p=0.069), but not with any of the consumption factors. Total cholesterol was explained by age (adjusted b=0.5, p=0.002) and body fat percentage (b=1.05, p=0.024). HDL-c was marginally associated with sex (Male b=-8.3, p=0.08), while triglycerides were associated with age and obesity (overweight and Class-I, b=0.04, p=0.001 and b=0.04, p=0.04, respectively). No collinearity was found in the analyzed regressions (VIF between 0.1 and 3.4). Conclusion: Our findings suggest that cholesterol and other lipid traits are primarily influenced by genetic factors, with diet playing a minor role. Nopal, vegetables, and fruit showed no significant effects on serum lipid levels in our study. A limitation of our study is its cross-sectional design, and future research could benefit from longitudinal studies with controlled amounts of nopal and other foods

    Pilot study of an online intervention for young people with a first psychotic episode: Thinkapp

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    Design and validation of the 1-week memory battery for assessing episodic memory and accelerated long-term forgetting in cognitively unimpaired subjects

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    Subtle decline in memory is thought to arise in the preclinical phase of Alzheimer's disease (AD). However, detecting these initial cognitive difficulties cross-sectionally has been challenging, and the exact nature of the decline is still debated. Accelerated long-term forgetting (ALF) has been recently suggested as one of the earliest and most sensitive indicators of memory dysfunction in subjects at risk of developing AD. The objective of this study was to design and validate the 1-week memory battery (1WMB) for assessing episodic memory and ALF in cognitively unimpaired individuals.The 1WMB is unique in that it assesses multimodal memory and measures recall at both short delay (20 min) and at long term (1 week). Forty-five cognitively unimpaired subjects were assessed with 1WMB and standardized neuropsychological tests. Subjective cognitive decline (SCD), levels of anxiety and depression, and cognitive reserve were also measured.The tests of 1WMB showed a high internal consistency, and concurrent validity was observed with standard tests of episodic memory and executive functions. The analysis revealed a greater loss of information at 1 week compared to short-term forgetting (20 min). Performance in the 1WMB was affected by age and educational level, but was not associated with levels of anxiety and depression. Unlike standard tests, performance in the 1WMB correlated with measures of SCD.Our findings indicate that the 1WMB has good psychometric properties, and future studies are needed to explore its potential usefulness to assess cognitively unimpaired subjects at increased risk of developing AD. (PsycInfo Database Record (c) 2023 APA, all rights reserved)

    A spatial dissection of the Arabidopsis floral transcriptome by MPSS

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    <p>Abstract</p> <p>Background</p> <p>We have further characterized floral organ-localized gene expression in the inflorescence of <it>Arabidopsis thaliana </it>by comparison of massively parallel signature sequencing (MPSS) data. Six libraries of RNA sequence tags from immature inflorescence tissues were constructed and matched to their respective loci in the annotated <it>Arabidopsis </it>genome. These signature libraries survey the floral transcriptome of wild-type tissue as well as the floral homeotic mutants, <it>apetala1, apetala3, agamous</it>, a <it>superman/apetala1 </it>double mutant, and differentiated ovules dissected from the gynoecia of wild-type inflorescences. Comparing and contrasting these MPSS floral expression libraries enabled demarcation of transcripts enriched in the petals, stamens, stigma-style, gynoecia, and those with predicted enrichment within the sepal/sepal-petals, petal-stamens, or gynoecia-stamens.</p> <p>Results</p> <p>By comparison of expression libraries, a total of 572 genes were found to have organ-enriched expression within the inflorescence. The bulk of characterized organ-enriched transcript diversity was noted in the gynoecia and stamens, whereas fewer genes demonstrated sepal or petal-localized expression. Validation of the computational analyses was performed by comparison with previously published expression data, <it>in situ </it>hybridizations, promoter-reporter fusions, and reverse transcription PCR. A number of well-characterized genes were accurately delineated within our system of transcript filtration. Moreover, empirical validations confirm MPSS predictions for several genes with previously uncharacterized expression patterns.</p> <p>Conclusion</p> <p>This extensive MPSS analysis confirms and supplements prior microarray floral expression studies and illustrates the utility of sequence survey-based expression analysis in functional genomics. Spatial floral expression data accrued by MPSS and similar methods will be advantageous in the elucidation of more comprehensive genetic regulatory networks governing floral development.</p
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