394 research outputs found

    A full-scale in situ heating test for high-level nuclear waste disposal: observations, analysis and interpretation

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    The paper describes the performance, observations and interpretation of a large-scale in situ heating test that simulates a disposal concept for heat-emitting, high-level nuclear waste. In the experiment, heaters are emplaced in the axis of a tunnel excavated in granite to simulate the heat production of radioactive waste. The test is fully instrumented, and attention is focused on the thermo-hydro-mechanical (THM) behaviour of the near-field region constituted by the compacted bentonite barrier surrounding the heater and the immediately adjacent rock. Interpretation of the test is assisted by the performance of a coupled numerical analysis based on a formulation that incorporates the relevant THM phenomena. Initial and boundary conditions for the analysis as well as material parameters are determined from an extensive programme of field and laboratory experiments. The paper presents and discusses the thermal, hydraulic and mechanical observations in the bentonite barrier and in the host rock. Special attention is paid to the progress of hydration in the barrier, to the effects of heating and vapour transport, and to the development of swelling pressures in the barrier. After five years of heating, one of the heaters was switched off and the experiment was partially dismantled, allowing the final state of the barrier to be observed directly. The numerical analysis performed has proved able to represent the progress of the experiment very satisfactorily. In addition, predictions concerning the final state of the clay barrier are very close to the observations obtained during dismantling. The performance and analysis of the in situ test have significantly enhanced the understanding of a complex THM problem and have proved the capability of the numerical formulation to provide adequate predictive capacit

    Simulation of non-radiative energy transfer in photosynthetic systems using a quantum computer

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    Photosynthesis is an important and complex physical process in nature, whose comprehensive understanding would have many relevant industrial applications, for instance in the field of energy production. In this paper we propose a quantum algorithm for the simulation of the excitonic transport of energy, occurring in the first stage of the process of photosynthesis. The algorithm takes in account the quantum and environmental effects (pure-dephasing), influencing the quantum transport. We performed quantum simulations of such phenomena, for a proof of concept scenario, in an actual quantum computer the IBM Q, of 5 qubits. We validate the results with the Haken-Str\"obl model and discuss the influence of environmental parameters on the efficiency of the energy transport.POCI-01-0145-FEDER-03094

    Power Transformer Failure Prediction: Classification in Imbalanced Time Series

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    This paper describes a study on applying data mining techniques to power transformer failure prediction. The data set used consisted not only on DGA tests, but also in other tests done to the transformer’s insulating oil. This dataset presented several challenges, such as highly imbalanced classes (common in failure prediction problems), and the temporal nature of the observations. To overcome these challenges, several techniques were applied for prediction and better understand the dataset. Pre-processing and temporality incorporation in the dataset is discussed. For prediction, a 1-class and 2-class SVM, decision trees and random forests, as well as a LSTM neural network were applied to the dataset. As the prediction performance was low (high false-positive rate), we conducted a test to ascertain if the amount of data collected was sufficient. Results indicate that the frequency of data collection was not adequate, hinting that the degradation period was shorter than the periodicity of data collection

    Chronic effects of different intensities of power training on neuromuscular parameters in older people: a systematic review with meta-analysis

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    Background Power training (PT) has been shown to be an efective method for improving muscle function, includ‑ ing maximal strength, measured by one-repetition maximum (1RM), and power output in older adults. However, it is not clear how PT intensity, expressed as a percentage of 1RM, afects the magnitude of these changes. The aim of this systematic review (International prospective register of systematic reviews—PROSPERO—registration: CRD42022369874) was to summarize the evidence from randomized clinical trials (RCT) assessing the efects of lowintensity (≤49% of 1RM) and moderate-intensity (50–69% of 1RM) versus high-intensity (≥70% of 1RM) PT on maximal power output and maximal strength in older adults. Methods We included RCTs that examined the efects of diferent intensities of power training on maximum strength and power output in older people. The search was performed using PubMed, LILACS, Embase, and Scopus. Methodological quality was assessed using the preferred reporting items for systematic reviews and meta-analyses (PRISMA 2020 statement checklist), and the quality of evidence was determined using the PEDro scale. Data were analyzed using standardized mean diferences (SMD) with a 95% confdence interval (CI), and random efects models were used for calculations. A signifcance level of p≤0.05 was accepted. Results Three RCTs assessing 179 participants, all of high methodological quality, were included. There were no sig‑ nifcant diferences between diferent PT intensities in terms of power output gains for leg press [SMD=0.130 (95% CI −0.19, 0.45), p=0.425] and knee extension exercises [SMD: 0.016 (95% CI −0.362, 0.395), p=0.932], as well as leg press 1RM increases [SMD: 0.296 (95% CI −0.03, 0.62); p=0.072]. However, high-intensity PT (70–80% of 1RM) was sig‑ nifcantly more efective than low-intensity PT in increasing 1RM for knee extension exercise [SMD: 0.523 (95% CI 0.14, 1.91), p=0.008]. Conclusions PT performed at low-to-moderate intensities induces similar power gains compared to high-inten‑ sity PT (70–80% of 1RM) in older adults. Nonetheless, the infuence of PT intensity on lower-limb strength gains seems to be dependent on the assessed exercise. Cautious interpretation is warranted considering the inclusion of only three studies

    IMP dehydrogenase rod/ring structures in acral melanomas

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    Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Acral lentiginous melanoma (ALM) is a rare subtype of melanoma with aggressive behavior. IMPDH enzyme, involved in de novo GTP biosynthesis, has been reported to assemble into large filamentary structures called rods/rings (RR) or cytoophidium (cellular snakes). RR assembly induces a hyperactive state in IMPDH, usually to supply a high demand for GTP nucleotides, such as in highly proliferative cells. We investigate whether aggressive melanoma tumor cells present IMPDH-based RR structures. Forty-five ALM paraffin-embedded tissue samples and 59 melanocytic nevi were probed with anti-IMPDH2 antibody. Both the rod- and ring-shaped RR could be observed, with higher frequency in ALM. ROC curve analyzing the proportions of RR-positive cells in ALM versus nevi yielded a 0.88 AUC. Using the cutoff of 5.5% RR-positive cells, there was a sensitivity of 80% and specificity of 85% for ALM diagnosis. In ALM, 36 (80%) showed RR frequency above the cutoff, being classified as RR-positive, compared with only 9 (15%) of the nevi (p 4.0mm, compared with only 29% in the RR-low/negative (p = .039). We propose that screening for RR structures in biopsy specimens may be a valuable tool helping differentiate ALM from nevi and accessing tumor malignancy

    Planting time for maximization of yield of vinegar plant calyx (Hibiscus sabdariffa L.)

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    Objetivou-se avaliar a produtividade de cálices de Hibiscus sabdariffa L., planta medicinal, em quatro épocas de plantio em Lavras M.G. Os tratamentos foram quatro épocas de plantio (18 de outubro; 15 de novembro; 18 de dezembro de 2001 e 15 de janeiro de 2002) e realizada uma colheita quando praticamente não existiam cálices em desenvolvimento, quase no final do ciclo da planta. Foram considerados os números de cálices por planta, as fitomassas frescas e secas dos cálices e a qualidade. Concluiu-se que a época de plantio influenciou o rendimento por planta e as fitomassas frescas e secas dos cálices, diferindo entre si pelo teste de Tukey a 5%. No plantio de outubro, houve maior rendimento (2.522 kg/ha), com produção de 5,24 vezes a mais em relação ao plantio do mês de janeiro (481 kg/ha). Os plantios nos meses de novembro e dezembro tiveram produções de 1.695 e 1.093 kg.ha-1 de cálices secos, respectivamente, e em relação ao mês de janeiro, a produção foi 3,52 e 2,27 vezes a mais.Deve-se realizar a colheita assim que os cálices estiverem maduros, a fim de preservar a qualidade

    Estresse no trabalho e hipertensão arterial em mulheres no Estudo Pró-Saúde: Estudo Pró-Saúde (Pro-Health Study)

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    Con el objetivo de analizar la asociación entre estrés en el trabajo e hipertensión arterial en la población femenina, fue realizado estudio transversal con 1.819 mujeres participantes del Estudio Pro-Salud en Rio de Janeiro, Sureste de Brasil, entre 1999 y 2001. Fue utilizada la versión brasilera de la escala reducida de estrés en el trabajo (modelo demanda-control). La prevalencia global de hipertensión arterial conferida (>;140/90 mmHg y/o uso de medicamento anti-hipertensivo) fue de 24%. Comparadas con participantes con trabajo clasificado como de baja exigencia, las tasas ajustadas de alta exigencia, pasivos y activos, fueron, respectivamente, de 0,93 (IC 95%: 0,72;1,20), 1,06 (IC 95%: 0,86;1,32) y 1,14 (IC 95%: 0,88;1,47). Se sugiere la realización de análisis longitudinales para elucidar el papel de estas características psicosociales del ambiente de trabajo en la determinación de la hipertensión arterial.Com o objetivo de analisar a associação entre estresse no trabalho e hipertensão arterial na população feminina, foi realizado estudo transversal com 1.819 mulheres participantes do Estudo Pró-Saúde no Rio de Janeiro, RJ, entre 1999 e 2001. Foi utilizada a versão brasileira da escala reduzida de estresse no trabalho (modelo demanda-controle). A prevalência global de hipertensão arterial aferida (>;140/90 mmHg e/ou uso de medicação anti-hipertensiva) foi de 24%. Comparadas com participantes com trabalho classificado como de baixa exigência, as razões ajustadas de prevalências de hipertensão arterial de mulheres em trabalhos de alta exigência, passivos e ativos, foram, respectivamente, de 0,93 (IC 95%: 0,72;1,20), 1,06 (IC 95%: 0,86;1,32) e 1,14 (IC 95%: 0,88;1,47). Sugere-se a realização de análises longitudinais para elucidar o papel dessas características psicossociais do ambiente de trabalho na determinação da hipertensão arterial.This study aimed to analyze the association between job strain and hypertension in the female population. A cross-sectional study was performed with 1,819 women who participated in the Estudo Pró-Saúde (Pro-Health Study), in the city of Rio de Janeiro, Southeastern Brazil, between 1999 and 2001. The Brazilian version of the short version of the Job Stress Scale (demand-control model) was used. Overall prevalence of measured hypertension (>;140/90 mmHg and/or antihypertensive drug use) was 24%. Compared to participants with jobs classified as low strain, adjusted prevalence ratios for hypertension in women who performed passive and active high-strain jobs were, respectively, 0.93 (95% CI: 0.72;1.20), 1.06 (95% CI: 0.86;1.32) and 1.14 (95% CI: 0.88;1.47). Longitudinal analyses should be performed to clarify the role of these work environment psychosocial characteristics as a determinant of hypertension
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