561 research outputs found

    MINE DEWATERING: A VERITABLE COMPONENT IN MINE COST ANALYSIS IN THE DEVELOPMENT AND MINING OF THE LAFIA-OBI COAL, NIGERIA

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    The impact of water in surface and underground mining activities is of great concern to Mining Engineers and Geoscientists to the effect that its accumulation in excess quantity can render mining of minerals ineffective. Surface and underground mines must therefore constantly be dewatered in order to forestall over-flooding and its attended effects on mining machinery, infrastructures industrial health, and productivity. In mine planning and design the cost of dewatering of mines is often captured as capital costs at the initial stage of mine development and afterwards in the cause of mining as operating costs both playing significant roles in profit or loss of Mining companies. Mines are often excavated below the water table where mine voids serve as low-pressure sinks inducing groundwater to move to the openings from the surrounding saturated rock. The result is the dewatering of nearby rock units via drainage of fractures and water-bearing strata in contact with the mine workings. There is also the potential for impacts to more remote water-bearing units and surface water bodies depending on the degree of hydrologic communication. The extent and severity of the impact on the local surface water and groundwater systems depends on the depth of the mine, the topographic and hydro-geologic setting, and the hydrologic characteristics of adjacent strata. The dewatering of mines and its cost implications starts from mineral exploration and mine development from where the rate of water flow is approximated thereby providing the initial clue to the choice of dewatering pumps and other drainage infrastructures. The paper dwells on the sources of water and its menace in surface and sub-surface mines, its control, and effects on the cost analysis of mineral investments

    A Study of Growth Based Morphological Development in Neural Network Controlled Walkers

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    Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] In nature, the physical development of the body that takes place in parallel to the cognitive development of the individual has been shown to facilitate learning. This opens up the question of whether the same principles could be applied to robots in order to accelerate the learning of controllers and, if so, how to apply them effectively. In this line, several authors have run experiments, usually quite complex and heterogeneous, with different levels of success. In some cases, morphological development seemed to provide an advantage and in others it was clearly irrelevant or even detrimental. Basically, morphological development seems to provide an advantage only under some specific conditions, which cannot be identified before running an experiment. This is due the fact that there is still no agreement on the underlying mechanisms that lead to success or on how to design morphological development processes for specific problems. In this paper, we address this issue through the execution of different experiments over a simple, replicable, and straightforward experimental setup that makes use of different neural network controlled walkers together with a morphological development strategy based on growth. The morphological development processes in these experiments are analyzed both in terms of the results obtained by the different walkers and in terms of how their fitness landscapes change as the morphologies develop. By comparing experiments where morphological development improves learning and where it does not, a series of initial insights have been extracted on how to design morphological development processes.This work has been partially funded by the Ministerio de Ciencia, Innovación y Universidades of Spain/FEDER (grant RTI2018-101114-B-I00), Xunta de Galicia (EDC431C-2021/39) and the Centro de Investigación de Galicia “CITIC”, funded by Xunta de Galicia and the European Union (European Regional Development Fund- Galicia 2014-2020 Program), by grant ED431G 2019/01. Funding for open access charge: Universidade da Coruña/CISUG. We also want to thank CESGA (Centro de Supercomputación de Galicia. https://www.cesga.es/) for the possibility of using its resourcesXunta de Galicia; EDC431C-2021/39Xunta de Galicia; ED431G 2019/0

    Is profitable to play in Spanish Soccer First Division?

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    El artículo presenta la primera fase de un estudio del fútbol español, cuyo objetivo es averiguar si es rentable jugar en Primera División de fútbol (1ª) para cualquier equipo profesional y si todos los clubes de 2ªA deberían aspirar al ascenso. Se comparan resultados en la población seleccionada y en dos grupos de la misma: equipos que se han mantenido en 1ª y equipos ascensor. Se examinan mediante análisis exploratorio de datos resultados económicos y deportivos, se identifican factores que influyen en su variación y se clasifican los clubes según dichos factores. También se determina la influencia de ascensos y descensos en los resultados. Se deduce que los equipos ascensor obtienen peores resultados aun jugando en la misma liga. Además, a su estabilidad económico financiera le afecta más el ascenso y descenso continuo que el mantenerse en una categoría concreta. Finalmente, que la “gestión del miedo” no siempre conduce a una mejor clasificación y añade tensión financiera. Se concluye que no a todos los clubes les conviene militar en 1ª división de fútbol, que ésta debe reestructurarse y se debe reforzar la 2ªAThe paper presents the first phase of a Spanish football study. The aim is to determine if it is profitable to play in 1ª D league for any professional team and if all clubs in 2ª A division should aspire to climb. Various results are compared in the selected population and also in two groups identified: equipment that have remained in 1ªD and “elevator teams”. The economics and sports results are examined by exploratory data analysis. We identify factors that are influence in change and the teams are classified according to these factors. Finally the influence of promotion and relegation in these results is determined. It follows that the "Fear Management" doesn’t always lead to better classification and adds financial stress, “elevator equipment” that perform worse even playing in the same league and its economic and financial stability will most affect the rise and decline that continued the stay in a particular category. We conclude: not all clubs suit them military in 1ª, it would be to restructure and strengthen the 2ª

    Activity profile of top-class association football referees in relation to fitness test performance and match standard

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    The aim of this study was to examine the kinematic activity profiles, cardiovascular responses and physical fitness of top-class football referees (n=11) during the FIFA Confederations Cup 2005. Computerised match-analyses (n=9) were performed with a two-dimensional photogrammetric video system, and the cardiovascular demand imposed on the referees (n=12) was measured using heart rate recordings. Total distance covered was 10,218, s=643 m of which 3531, s=510 m was covered at high intensities (>3.6 m.s(-1)). Both total distance covered (r2=0.59; P=0.02) and high-intensity activities (r2=0.44; P=0.05) were related to the distance covered by the ball in the same match. The referees ran at high speed 37% further (P=0.01) in the actual tournament than during under-17 top-level officiating. After the 5-min interval during which high-speed running peaked, in the following 5 min the performance was reduced by 19% (P=0.01) in relation to the mean of the game. Mean heart rate was 161, s=9 b.min(-1) (86, s=3% of maximal heart rate (HRmax)). Mean heart rate (expressed as percentage of HRmax) was related in part (r2=0.36; P5 m.s(-1)) best describes the physical performance of referees; (3) heart rate recording can be a useful tool to determine the most intense periods of a match and (4) the new fitness tests adopted by FIFA were poor predictors of match activities

    Apparent digestibility and metabolizable energy content of lipid sources in poultry

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    A trial was conducted to determine the apparent digestibility (ATTD) and AME content of different lipid sources in 21d-old broilers. There were a control diet based on corn and soybean meal without any supplemental fat and 6 additional diets forming a 3x2 factorial with 3 sources of fat (soy oil, SBO; reconstituted monoglyceride oil, RMG; and reconstituted triglyceride oil, RTG) included in the diet (3 or 6%) at expenses (wt:wt) of the basal diet

    Activity profile of top-class female soccer refereeing in relation to the position of the ball

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    The aim of this study was to describe the activity profile of top-class female soccer referees during competition and to relate it to the position of the ball. Ten matches from the Fédération Internationale de Football Association (FIFA) under-20 female World Championships held in Russia in 2006 were filmed and the kinematical parameters of the female referees (n = 10) and the ball were determined using a two-dimensional photogrammetric video system based on direct linear transformation (DLT) algorithms. Total distance covered during a match was 10 km, of which 1.3 km represented high-intensity activities (>13 km/h). The referees’ highest mobility was achieved in the initial 15 min of the match, covering greater distance and performing more intense exercise (P < 0.01) than in the final 15-min of the game. Mean distance from the referee to the ball was 19.5 ± 2.4 m, with no significant differences between 15 min match periods. The results of this study show that: (1) the physical demands placed on top-class female referees are much like those experienced during male moderate-standard refereeing and (2) the referees were able to maintain the distance from the ball throughout the matc

    Oct4 Is a Key Regulator of Vertebrate Trunk Length Diversity

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    The deposited article version is a post-print version (final draft post-refereeing) and included supplementary information.Vertebrates exhibit a remarkably broad variation in trunk and tail lengths. However, the evolutionary and developmental origins of this diversity remain largely unknown. Posterior Hox genes were proposed to be major players in trunk length diversification in vertebrates, but functional studies have so far failed to support this view. Here we identify the pluripotency factor Oct4 as a key regulator of trunk length in vertebrate embryos. Maintaining high Oct4 levels in axial progenitors throughout development was sufficient to extend trunk length in mouse embryos. Oct4 also shifted posterior Hox gene-expression boundaries in the extended trunks, thus providing a link between activation of these genes and the transition to tail development. Furthermore, we show that the exceptionally long trunks of snakes are likely to result from heterochronic changes in Oct4 activity during body axis extension, which may have derived from differential genomic rearrangements at the Oct4 locus during vertebrate evolution.Fundação para a Ciência e a Tecnologia grants: ( PTDC/BEX-BID/0899/2014, SFRH/BD/51876/2012); Santa Casa da Misericordia de Lisboa grant: (SCML-MC-60-2014); Howard Hughes Medical; HHMI international graduate student research fellowship.info:eu-repo/semantics/publishedVersio

    Implementing concurrent-training and nutritional strategies in professional football: a complex challenge for coaches and practitioners

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    Purpose: To study concurrent-training (CT) and nutritional practices within a professional soccer team. Methods: Twenty-one professional football players competing in the English professional league participated in this study (mean ± standard deviations [M ± SD] 26 ± 4 years, stature 1.84 ± 0.1 m, body mass 83 ± 7 kg, VO2max; 58 ± 3 ml · kg−1 · min−1). A range of internal and external training metrics, the organisation of CT (training sequence, training rest period between bouts) and the nutritional intake around CT (timing, type and quantity) was collected for 10 weeks. Results: CT; n = 17 (endurance-training [ET] + resistance-training [RT]; n = 11; RT + ET; n = 6) rest period between bouts was not consistent and varied depending on the sequence of CT (RT + ET, 75 ± 48 min; ET + RT; 60 ± 5 min; P = 0.04). sRPE of football-specific ET was higher in RT + ET (RT + ET, 7 ± 1; ET + RT, 6 ± 1; P = 0.05). The timing of meals around training was influenced by the organisation of CT. Subsequently, CHO consumption before training session one was significantly less in RT + ET (CHO 0.10 ± 0.5 g · kg−1 vs. CHO 0.45 ± 0.2 g · kg−1). Conclusion: The present data demonstrate that the organisation of CT (i.e., exercise order and/or recovery time between bouts) and nutrition (i.e., timing of meal intake) can be unsystematic in the applied environment. The organisation of training and nutrition might influence the players’ ability to perform high-intensity actions in secondary training sessions and could potentially impact acute metabolic processes associated with muscle recovery and muscle adaptation

    Ameliorative Effects of Soya Bean Oil and Vitamin C on Liver Enzymes in Ethanol -Induced Oxidative Stress in Wistar Rats

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    Abstract: The protective potential of soya bean oil and vitamin C on Ethanol-induced oxidative stress i
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