157 research outputs found

    Detecting groundwater discharge dynamics from point-to-catchment scale in a lowland stream : Combining hydraulic and tracer methods

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    Acknowledgements. We would like to thank members of the Northern Rivers Institute, Aberdeen University, for helpful discussions of data. We also thank Lars Rasmussen, Jolanta Kazmierczak and Charlotte Ditlevsen for help in the field. This study is part of the Hydrology Observatory, HOBE (http://www.hobe.dk), funded by the Villum Foundation and was as well funded by the Aarhus University Research Foundation.Peer reviewedPublisher PD

    Тепловое измерение и его применение для диагностики масляных трансформаторов распределительных сетей

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    In the first part of the paper the theory of infrared radiation and the use of nondestructive measurement of electrical devices by means of thermovision are under analysis. In the second part of paper basic principles and application of non-contact temperature measurement are examined. In the third part of paper thermal processes in distribution oil transformer – temperature in dependence on height of oil transformer and temperature distribution in sectional plan of oil transformer – are considered. In the fourth part of paper, by means of the experimental measurements and subsequent analysis, practical thermal imaging and contact thermal measurements by optical detectors for the diagnosis of distribution oil transformers in the field of mechanical strength of windings are shown. In this paper, we wanted to show out the possibility of using thermal measurements in this field of analysis and detection of quality of winding for distribution oil transformer. It is possible to use these methods to localize places of faults, and they are also applicable for the diagnosis and detection of disorders of the quality of materials and other anomalies during operation of the equipment. By means of the experimental measurements followed by diagnostic analysis the practical use of thermovision and optical sensors for diagnostics of power oil transformers in field mechanical strength and quality of winding is demonstrated.Cтатья посвящена анализу теории инфракрасного излучения и применения неразрушающего контроля с помощью электрических приборов и тепловизионного оборудования. Изложены основные принципы использования бесконтактного измерения температуры. Проанализированы тепловые процессы в силовом масляном трансформаторе: температура в зависимости от его высоты и распределение температуры в секционном плане масляного трансформатора. Рассмотрены экспериментальные тепловизионное и контактные тепловые измерения оптическими детекторами для диагностики механической прочности обмоток силовых масляных трансформаторов. Также показана возможность использования тепловых измерений для анализа и определения качества обмотки масляного трансформатора. Эти методы позволяют локализовать места неисправностей и могут использоваться для диагностики и выявления нарушений качества материалов и других аномалий в ходе эксплуатации оборудования. Путем экспериментальных измерений с последующим анализом определено практическое применение тепловизионных и оптических датчиков для диагностики силовых масляных трансформаторов в части механической прочности и качества обмоток

    Predicting the Unpredictable: Estimating Human Performance Parameters for Off-Nominal Events

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    A parameter meta-analysis was conducted to characterize human responses to off-nominal events. The probability of detecting an off-nominal event was influenced by characteristics of the offnominal event scenario (phase of flight, expectancy, and event location) and the presence of advanced cockpit technologies (head-up displays, highway-in-the-sky displays, datalink, and graphical route displays). The results revealed that the presence of these advanced technologies hindered event detection reflecting cognitive tunneling and pilot complacency effects

    Диагностика частотной области изоляции трансформатора

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    The first part of paper deals with the base information about diagnostics of power transformers. In this part are presented differently insulating methods, for example method of recovery voltage method, method of polarization and depolarization currents and chromatographic analysis. The second part of paper deals use of method of frequency domain spectroscopy for oil power transformers. This method is used in analysis insulating condition of power transformer with system of oil-paper. It was found, that the results of these tests are highly impacted by the operating temperature during the experimental measurement. Moisture and conductivity between insulating paper and oil in an insulating system are highly dependent from temperature. In the other part, the paper presents experimental results of the frequency diagnostic measurement for a real single-phase traction transformer 110/27 kV at different operating temperatures and states (with oil and without). Finally in the last part, the paper presents comparing frequency insulating measurements among several the same single-phase transformers 110/27 kV

    Circadian Effects on Simple Components of Complex Task Performance

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    The goal of this study was to advance understanding and prediction of the impact of circadian rhythm on aspects of complex task performance during unexpected automation failures, and subsequent fault management. Participants trained on two tasks: a process control simulation, featuring automated support; and a multi-tasking platform. Participants then completed one task in a very early morning (circadian night) session, and the other during a late afternoon (circadian day) session. Small effects of time of day were seen on simple components of task performance, but impacts on more demanding components, such as those that occur following an automation failure, were muted relative to previous studies where circadian rhythm was compounded with sleep deprivation and fatigue. Circadian low participants engaged in compensatory strategies, rather than passively monitoring the automation. The findings and implications are discussed in the context of a model that includes the effects of sleep and fatigue factors

    Efficacy of Fumaric Acid Esters in the R6/2 and YAC128 Models of Huntington's Disease

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    Huntington's disease (HD) is an autosomal dominantly inherited progressive neurodegenerative disease. The exact sequel of events finally resulting in neurodegeneration is only partially understood and there is no established protective treatment so far. Some lines of evidence speak for the contribution of oxidative stress to neuronal tissue damage. The fumaric acid ester dimethylfumarate (DMF) is a new disease modifying therapy currently in phase III studies for relapsing-remitting multiple sclerosis. DMF potentially exerts neuroprotective effects via induction of the transcription factor “nuclear factor E2-related factor 2” (Nrf2) and detoxification pathways. Thus, we investigated here the therapeutic efficacy of DMF in R6/2 and YAC128 HD transgenic mice which mimic many aspects of HD and are characterized by an enhanced generation of free radicals in neurons. Treatment with DMF significantly prevented weight loss in R6/2 mice between postnatal days 80–90. At the same time, DMF treatment led to an attenuated motor impairment as measured by the clasping score. Average survival in the DMF group was 100.5 days vs. 94.0 days in the placebo group. In the histological analysis on day 80, DMF treatment resulted in a significant preservation of morphologically intact neurons in the striatum as well as in the motor cortex. DMF treatment resulted in an increased Nrf2 immunoreactivity in neuronal subpopulations, but not in astrocytes. These beneficial effects were corroborated in YAC128 mice which, after one year of DMF treatment, also displayed reduced dyskinesia as well as a preservation of neurons. In conclusion, DMF may exert beneficial effects in mouse models of HD. Given its excellent side effect profile, further studies with DMF as new therapeutic approach in HD and other neurodegenerative diseases are warranted

    Ideal cardiovascular health and inflammation in European adolescents: The HELENA study

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    Background and aims Inflammation plays a key role in atherosclerosis and this process seems to appear in childhood. The ideal cardiovascular health index (ICHI) has been inversely related to atherosclerotic plaque in adults. However, evidence regarding inflammation and ICHI in adolescents is scarce. The aim is to assess the association between ICHI and inflammation in European adolescents. Methods and results As many as 543 adolescents (251 boys and 292 girls) from the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study, a cross-sectional multi-center study including 9 European countries, were measured. C-reactive protein (CRP), complement factors C3 and C4, leptin and white blood cell counts were used to compute an inflammatory score. Multilevel linear models and multilevel logistic regression were used to assess the association between ICHI and inflammation controlling by covariates. Higher ICHI was associated with a lower inflammatory score, as well as with several individual components, both in boys and girls (p < 0.01). In addition, adolescents with at least 4 ideal components of the ICHI had significantly lower inflammatory score and lower levels of the study biomarkers, except CRP. Finally, the multilevel logistic regression showed that for every unit increase in the ICHI, the probability of having an inflammatory profile decreased by 28.1% in girls. Conclusion Results from this study suggest that a better ICHI is associated with a lower inflammatory profile already in adolescence. Improving these health behaviors, and health factors included in the ICHI, could play an important role in CVD prevention

    Dietary animal and plant protein intakes and their associations with obesity and cardio-metabolic indicators in European adolescents: The HELENA cross-sectional study

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    Background: Previous studies suggest that dietary protein might play a beneficial role in combating obesity and its related chronic diseases. Total, animal and plant protein intakes and their associations with anthropometry and serum biomarkers in European adolescents using one standardised methodology across European countries are not well documented. Objectives: To evaluate total, animal and plant protein intakes in European adolescents stratified by gender and age, and to investigate their associations with cardio-metabolic indicators (anthropometry and biomarkers). Methods: The current analysis included 1804 randomly selected adolescents participating in the HELENA study (conducted in 2006-2007) aged 12.5-17.5 y (47% males) who completed two non-consecutive computerised 24-h dietary recalls. Associations between animal and plant protein intakes, and anthropometry and serum biomarkers were examined with General linear Model multivariate analysis. Results: Average total protein intake exceeded the recommendations of World Health Organization and European Food Safety Authority. Mean total protein intake was 96 g/d (59% derived from animal protein). Total, animal and plant protein intakes (g/d) were significantly lower in females than in males and total and plant protein intakes were lower in younger participants (12.5-14.9 y). Protein intake was significantly lower in underweight subjects and higher in obese ones; the direction of the relationship was reversed after adjustments for body weight (g/(kg.d)). The inverse association of plant protein intakes was stronger with BMI z-score and body fat percentage (BF%) compared to animal protein intakes. Additionally, BMI and BF% were positively associated with energy percentage of animal protein. Conclusions: This sample of European adolescents appeared to have adequate total protein intake. Our findings suggest that plant protein intakes may play a role in preventing obesity among European adolescents. Further longitudinal studies are needed to investigate the potential beneficial effects observed in this study in the prevention of obesity and related chronic diseases

    Evaluation of iron status in European adolescents through biochemical iron indicators: the HELENA Study

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    BACKGROUND/OBJECTIVES: To assess the iron status among European adolescents through selected biochemical parameters in a cross-sectional study performed in 10 European cities. SUBJECTS/METHODS: Iron status was defined utilising biochemical indicators. Iron depletion was defined as low serum ferritin (SF8.5 mg/l) plus iron depletion. Iron deficiency anaemia (IDA) was defined as ID with haemoglobin (Hb) below the WHO cutoff for age and sex: 12.0 g/dl for girls and for boys aged 12.5-14.99 years and 13.0 g/dl for boys aged ≥15 years. Enzyme linked immunosorbent assay was used as analytical method for SF, sTfR and C-reactive protein (CRP). Subjects with indication of inflammation (CRP >5 mg/l) were excluded from the analyses. A total of 940 adolescents aged 12.5-17.49 years (438 boys and 502 girls) were involved. RESULTS: The percentage of iron depletion was 17.6%, significantly higher in girls (21.0%) compared with boys (13.8%). The overall percentage of ID and IDA was 4.7 and 1.3%, respectively, with no significant differences between boys and girls. A correlation was observed between log (SF) and Hb (r = 0.36, P < 0.01), and between log (sTfR) and mean corpuscular haemoglobin (r = -0.30, P < 0.01). Iron body stores were estimated on the basis of log (sTfR/SF). A higher percentage of negative values of body iron was recorded in girls (16.5%) with respect to boys (8.3%), and body iron values tended to increase with age in boys, whereas the values remained stable in girls. CONCLUSIONS: To ensure adequate iron stores, specific attention should be given to girls at European level to ensure that their dietary intake of iron is adequate.status: publishe
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