223 research outputs found

    Effects of thermal stress on physiological state and hormone concentrations in Holstein cows under arid climatic conditions

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    This study was conducted to investigate the effect of heat stress on the physiology of dairy cows and to detect the relationship between rectal temperature (RT) and respiration rate (RR), heart rate (HR), and plasma concentrations of cortisol, thyroxine, and prolactin. During the experiment, 44 Holstein cows were allocated to two groups for each season. The average temperature-humidity index (THI) values were 55 ± 2.31 in winter and 78 ± 1.9 in summer. As the THI values increased from 55 to 78, RR rose by 35 inspirations per minute, HR by 3 beats per minute, and RT by 1.2 °C. In addition, the average concentration of cortisol increased from 19.30 to 21.04 nmol/L, and prolactin from 58.52 to 129.79 ngm/L, whereas free thyroxine decreased from 15.43 to 14.01 pmol/L. Plasma sodium and potassium concentrations were similar in the two seasons. These results confirmed that RT is an indicator of the response in dairy cows to hot environmental temperatures. However, they also showed signs of stress, which were reflected in higher levels of cortisol and in certain physiological responses

    Evaluation de la fiabilité des structures fissurées en mode mixte en tenant compte des inspections

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    Simplicity versus complexity in modelling groundwater recharge in Chalk catchments

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    Models of varying complexity are available to provide estimates of recharge in headwater Chalk catchments. Some measure of how estimates vary between different models can help guide the choice of model for a particular application. This paper compares recharge estimates derived from four models employing input data at varying spatial resolutions for a Chalk headwater catchment (River Pang, UK) over a four-year period (1992-1995) that includes a range of climatic conditions. One model was validated against river flow data to provide a measure of their relative performance. Each model gave similar total recharge for the crucial winter recharge period when evaporation is low. However, the simple models produced relatively lower estimates of the summer and early autumn recharge due to the way in which processes governing recharge especially evaporation and infiltration are represented. The relative uniformity of land use, soil types and rainfall across headwater, drift-free Chalk catchments suggests that complex, distributed models offer limited benefits for recharge estimates at the catchment scale compared to simple models. Nonetheless, distributed models would be justified for studies where the pattern and amount of recharge need to be known in greater detail and to provide more reliable estimates of recharge during years with low rainfall.</p> <p style='line-height: 20px;'><b>Keywords:</b> Chalk, modelling, groundwater recharge</p

    The Learning by the Creation of Event: Theatrical Approach, Interactive, Co-Operative and Individualizing Pedagogy of Project (The Case of the Artistic Carnival of the PPP in the ISET of Gabès)

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    Abstract In the framework of the valorization of the pedagogy of project via the development of the learning by the event, we organized a day dedicated to the fair of the Professional Project personalized by a theatrical production of outputs animated by the students accompanied. This experience based on the adoption of the active pedagogy generated interesting results in terms of satisfaction, self-confidence, positive emotions, exceeding itself, vitality, pleasure and self-realization. An event, which constitutes a clinical case of active pedagogy, worthy of the reinvestments in the future. This document will attempt to synthesize this experience in describing, student the inputs to the catalysis of the participation and by analyzing the main results generated by this event

    Chloroformic and Methanolic Extracts of Olea europaea L. Leaves Present Anti-Inflammatory and Analgesic Activities

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    Olea europaea L. is used in traditional medicine in the Mediterranean areas. Its natural products are used in the treatment of different disorders, like fighting fever and some infectious diseases such as malaria, the treatment of arrhythmia, and relief of intestinal spasms. The aim of the current study is to investigate the possible anti-inflammatory and anatinociceptive effects of methanol and chloroformic extracts prepared from leaves of Olea europaea L. The anti-inflammatory and antinociceptive effects of the different extracts of Olea europaea leaves were assessed after intraperitoneal administration into rats and mice, using the carrageenan-induced paw edema model in rats to test the anti-inflammatory effect and the acetic acid-induced writhing in mice to test the analgesic effect. The chloroformic and methanolic leaves extracts, studied at the doses of 50, 100, and 200 mg/kg (Body Weight: BW), exhibited significant dose-dependent anti-inflammatory and analgesic activities. Based on the results obtained, it can be concluded that Olea europaea leaves extracts have anti-inflammatory and antinociceptive effects

    Engineering visible light emitting point defects in Zr-implanted polycrystalline AlN films

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    We have investigated the impact of thermal annealing gaseous atmosphere of argon, nitrogen, and forming gas on the structural and optical properties of thin polycrystalline AlN films subjected to high-energy zirconium ions implantation. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and atomic force microscopy measurements show that the structural and morphological properties of the Zr-implanted AlN films depend on the annealing gaseous environment. Post-implantation annealing under argon atmosphere yields the lowest structured surface roughness with increased grain size. Photoluminescence spectroscopy revealed multiple point defects and defect complexes related emission bands in the visible range. A series of absorption bands have been observed using photoluminescence excitation spectroscopy. The origin of the emission or absorption bands is identified and attributed to various types of point defects and defect complexes, theoretically reported for AlN. New emission and absorption peaks at 1.7eV (730nm) and 2.6eV (466nm), respectively, have been identified and attributed to the (ZrAl–VN)0 defect complexes

    Reliability analysis and inspection updating by stochastic response surface of fatigue cracks in mixed mode

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    The analysis of engineering structures under fatigue crack growth aims at ensuring an appropriate reliability level over the entire operational lifetime. This paper deals with a new approach, namely the Stochastic Response Surface, to couple finite element analysis and reliability methods. The stochastic collocation method provides an explicit expression of the limit state function related to fatigue failure. This expression is used in first and second order reliability methods in order to compute the failure probability at a given structural age. When inspection is carried out, the structural reliability can be easily updated in terms of the observed crack length. Two numerical applications dealing with fatigue crack growth are presented to illustrate the proposed method, showing its performance in terms of numerical efficiency and accuracy
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