Effects of plyometric jump training on the physical fitness of young male soccer players: Modulation of response by inter-set recovery interval and maturation status     

Rodrigo Ramirez-Campillo  Cristian Alvarez  Javier Sanchez-Sanchez  Maamer Slimani  Paulo Gentil  Mohamed Souhaiel Chelly 《Journal of sports sciences》2013,31(23):2645-2652

ABSTRACT

The effects of plyometric jump training on the physical fitness of male youth (age = 10–17 years) soccer players was examined in relation to inter-set recovery intervals and the maturity of the players in a single-blind, randomized-and controlled crossover trial. Jumping tests and kicking velocities were measured before (T₀), after a 6 week control period (T₁), after 6 weeks of plyometrics (T₂), after 6 weeks of wash-out (T₃), and after a further 6 weeks of plyometrics (T₄). Subjects were divided into pre- and post- peak-height-velocity (PHV) groups, and were randomly assigned to 30 s or 120 s inter-set intervals during periods T₂ and T₄. Any changes in jumping and maximum kicking velocities during T₁ and T_3, had trivial effect sizes (0.01–0.15), but small to moderate improvements (effect size = 0.20–0.99) were observed in both groups during T₂ and T₄. Gains in pre-PHV players were similar for the two inter-set intervals, but gains in post-PHV players were greater (p < 0.05) with an inter-set recovery of 120 s than with a 30 s recovery. We conclude that plyometric jump training improves the physical fitness of adolescents, irrespective of their maturity, but that in older individuals gains are greater with a longer inter-set recovery interval.  相似文献   

Promotion and Knowledge of Online Patent Literature Search to Enhance Scientific Output in Tanzania: Case of Two Universities in Zanzibar     

Abbas Mohamed Omar  Haji Ali Haji  Juliana James Manyerere 《International Information and Library Review》2020,52(1):1-9

Abstract

This study examines the promotion and knowledge of online patent literature search among students, librarians, and instructors to enhance university scientific output in Zanzibar. The study was guided by four key questions: What is the level of awareness of students, instructors and library staff about patent documents as source of information? To what extent do students and instructors access online patent databases? What is the library experience in training students about online patent literature searching?, and what are the challenges facing library and instructors in promoting patent literature search? The study used survey approach whereby questionnaire and interview were used to collect data. The recent literatures regarding online patent literature searching were also critically reviewed. A survey was conducted at two Universities in Zanzibar namely the State University of Zanzibar and Zanzibar University, whereby 20 library staff, 10 instructors and 140 undergraduate students from the School of Computing and the Faculty of Engineering were involved in this study. The findings show that more than three quarters of respondents were either partially aware or not aware at all about the existence of free online patent databases. Likewise, the majority of students had no enough skills of patent literature searching. However, usually the library organizes training on general online literature searching skills but patent literature searching was not effectively taught and a big challenge observed in this study regarding promotion of patent literature searching is inadequate patent searching skills among library and instructors. Based on the findings, the study proposed several recommendations to rectify the existing problem.  相似文献   

SRL-ESA-TextSum: A text summarization approach based on semantic role labeling and explicit semantic analysis     

Muhidin Mohamed  Mourad Oussalah 《Information processing & management》2019,56(4):1356-1372

Automatic text summarization attempts to provide an effective solution to today’s unprecedented growth of textual data. This paper proposes an innovative graph-based text summarization framework for generic single and multi document summarization. The summarizer benefits from two well-established text semantic representation techniques; Semantic Role Labelling (SRL) and Explicit Semantic Analysis (ESA) as well as the constantly evolving collective human knowledge in Wikipedia. The SRL is used to achieve sentence semantic parsing whose word tokens are represented as a vector of weighted Wikipedia concepts using ESA method. The essence of the developed framework is to construct a unique concept graph representation underpinned by semantic role-based multi-node (under sentence level) vertices for summarization. We have empirically evaluated the summarization system using the standard publicly available dataset from Document Understanding Conference 2002 (DUC 2002). Experimental results indicate that the proposed summarizer outperforms all state-of-the-art related comparators in the single document summarization based on the ROUGE-1 and ROUGE-2 measures, while also ranking second in the ROUGE-1 and ROUGE-SU4 scores for the multi-document summarization. On the other hand, the testing also demonstrates the scalability of the system, i.e., varying the evaluation data size is shown to have little impact on the summarizer performance, particularly for the single document summarization task. In a nutshell, the findings demonstrate the power of the role-based and vectorial semantic representation when combined with the crowd-sourced knowledge base in Wikipedia.  相似文献   

Simulation of intermittent thermal compression processes using adsorption technology     

Mohamed A. Gadalla 《Journal of The Franklin Institute》2007,344(5):725-740

This paper presents a dynamic model to simulate the adsorption-desorption processes associated with intermittent heat pump systems. This simulation plays an important role in sizing the adsorption systems for various types of applications in the design stage. A mathematical model that is based on the control volume approach was first developed and then discretized using the finite difference implicit scheme. The equations for the conservation of mass, momentum, and energy in the bed were derived for high-pressure and low-pressure segments, including the adsorbate (refrigerant), the adsorbent (Linde 13X), and the vessel wall. A pseudo-homogeneous model for the compression system was adopted. The numerical results that describe the adsorption-desorption history were obtained. It was found that the amount of the refrigerant recovered in the desorption process at the end of the cyclic operation is smaller than the amount adsorbed during the adsorption process. This indicates that the time for the regeneration process should be longer than the time for the adsorption process in order to raise the sieve temperature. In order to compare the simulated results with experimental data, numerical values for the heat transfer coefficients were theoretically evaluated. To assure the stability of the simulated results, the incremental time of system operation is kept equal or less than the value obtained from the minimum stability requirement. The simulated results of the temperature distribution history during system operation are in good agreement with the conducted experimental results, which led to the conclusion that the model can be used as an effective tool during the design stage and for the system development.  相似文献   

New approaches to facilitate learning from youth: Exploring the use of Photovoice in identifying local watershed issues     

Victoria Chanse  Amina Mohamed  Sacoby Wilson  Laura Dalemarre  Paul T. Leisnham  Amanda Rockler 《The Journal of environmental education》2017,48(2):109-120

In urbanized areas, incorporating residents’ concerns and priorities into the stormwater management debate has focused on adults rather than youth. This study used Photovoice, a tool that includes photographs taken by youth, to uncover youth concerns and perceptions about their local watersheds. This study consisted of a comparative study of two watersheds. Twenty students produced 468 photographs. Although both groups of students shared common themes regarding stormwater and pollution, these themes differed in level of concerns over local environmental issues, sentiments with particular features in their local watersheds, and concerns about local watersheds. From a methodological perspective, Photovoice provided a way of capturing youth perspectives and to identify important features and issues in their respective local watersheds.  相似文献   

PPP合同的风险及新的转移方式     

Mohamed Chohra  穆诗煜  成虎 《东南大学学报》2011,(4):458-462

本研究试图论证基于平衡的风险分担原则在解决公私合作伙伴关系(PPP)项目风险分担问题上是最有效的,并提出实施该原则的建议.为了满足公共部门和私人部门的不同利益和目标,PPP项目应建立一个可行及有利可图的风险分担机制.一个有效的风险分担机制既是项目文件准备的重要部分,也是PPP合同成功不可或缺的一部分.风险分担可用风险矩...  相似文献   

Exact performance analysis of OS modified versions with noncoherent integration in nonideal situations     

Mohamed B. El Mashade 《Journal of The Franklin Institute》2005,342(5):521-550

The radar signals returning from the targets being illuminated are usually accompanied by thermal noise and clutter. Constant false alarm rate (CFAR) processors are useful for detecting these targets in a background for which the parameters of the statistical distribution are not known and may be nonstationary. The ordered-statistics (OS) CFAR technique has been proven to work satisfactorily in both multiple-target and nonuniform clutter cases. Unfortunately, the large processing time taken by this scheme limits its practical uses. The modified versions of the OS processor have been proposed to replace it in these applications. They can reduce the processing time of the single-window OS detector in half without changing its useful properties. Our goal in this paper is to provide a complete detection analysis for the OS processor along with ordered-statistic greatest-of (OSGO) and ordered-statistic smallest-of (OSSO) modified versions, for M postdetection integrated pulses when the operating environment is nonideal. Analytical results of performance are presented in both multiple-target situations and in regions of clutter power transitions. The primary and the secondary interfering targets are assumed to be fluctuating in accordance with the Swerling II target fluctuation model. As the number of noncoherently integrated pulses increases, lower threshold values and consequently better detection performances are obtained in both homogeneous and multiple-target background models. However, the false alarm rate performance of OSSO-CFAR scheme at clutter edges worsens with increasing the postdetection integrated pulses. As predicted, the OSGO-CFAR detector accommodates the presence of spurious targets in the reference window, given that their number is within its allowable range in each local window, and controls the rate of false alarm when the contents of the reference cells have clutter boundaries. The OSSO-CFAR scheme is useful in the situation where there is a cluster of radar targets amongst the estimation cells.  相似文献   

The <Emphasis Type="Italic">MinK</Emphasis> framework: towards measuring individual knowledge     

Mohamed A F?RagabEmail author  Amr?Arisha 《知识管理研究与实践》2015,13(2):178-186

Knowledge is the currency of the current economy and a vital resource for sustaining organisational performance in today’s knowledge-based intensively competitive business environment. To avoid the detrimental consequences of knowledge loss, managers are urged to identify where knowledge stocks exist and how knowledge flows within their organisations by identifying knowledge holders among their employees. Although some studies have attempted to use different methods to measure knowledge at the organisational level, very few have addressed the individual knowledge holder. Moving from a critical literature review of the existing knowledge measurement approaches, this paper proposes a novel framework that enables organisations to measure individual knowledge in the business context using a set of metrics, which are subsequently validated via a series of in-depth interviews with senior managers. A summary of the managers’ views on individual knowledge measurement is presented, and reflections on the industry application of the proposed framework and recommendations for its improvement are also discussed.  相似文献   

Perceptions of Information Literacy Skills among Undergraduate Students in the Social Media Environment     

Ali Saif Al-Aufi  Hamed Mohamed Al-Azri  Nihad Ali Al-Hadi 《International Information and Library Review》2017,49(3):163-175

This study assessed information literacy perceptions of undergraduate students at Sultan Qaboos University in their use of social media. A quantitative approach was used to collect data from undergraduate students. The study consisted of 1,142 completed questionnaires by randomly selected participants. The results demonstrated overall moderate levels of perceptions toward the evaluation of information, information ethics, legal issues, and privacy issues. In evaluation of information, credibility of information was considered as an important factor to decide whether to use information for academic purposes. This study signifies the importance of understanding perceptions of information literacy among undergraduate students in a specific socio-cultural context. The results can also be generalized to similar academic institutions worldwide. It is also hoped that the study's findings will assist in developing contextual training programs or information literacy quizzes to promote information literacy in the social media environment.  相似文献   

An outranking approach for information retrieval     

Mohamed Farah  Daniel Vanderpooten 《Information Retrieval》2008,11(4):315-334

Over the last three decades, research in Information Retrieval (IR) shows performance improvement when many sources of evidence are combined to produce a ranking of documents. Most current approaches assess document relevance by computing a single score which aggregates values of some attributes or criteria. They use analytic aggregation operators which either lead to a loss of valuable information, e.g., the min or lexicographic operators, or allow very bad scores on some criteria to be compensated with good ones, e.g., the weighted sum operator. Moreover, all these approaches do not handle imprecision of criterion scores. In this paper, we propose a multiple criteria framework using a new aggregation mechanism based on decision rules identifying positive and negative reasons for judging whether a document should get a better ranking than another. The resulting procedure also handles imprecision in criteria design. Experimental results are reported showing that the suggested method performs better than standard aggregation operators.  相似文献