6,826 research outputs found

    THE EFFECT OF BACK SQUAT RESISTIVE LOADS ON THE BIOMECHANICAL PERFORMANCE OF DROP JUMPS IN MALE RUGBY PLAYERS

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    This study examined the effect of three different resistive loads (65%, 80%, & 93% of 1 RM) for the back squat on the biomechanical performance of the drop jump (DJ) in male rugby players. Twelve elite level rugby players participated in the study. Drop jumps were done prior to and after the back squat lifting at the different loads. All jumps were performed on a specially constructed sledge and force plate apparatus. Time in the air (flight time) and leg spring stiffness were the dependent variables. The results indicated that lifting at all loads significantly (p < 0.01) reduced flight time but lifting the 93% load caused a significant improvement (p < 0.05) in leg spring stiffness. From a practical viewpoint, the results support the use of a heavy back squatting prior to performing a fast SSC activity, such as drop jumping

    THE EFFECT OF A MAXIMAL STRETCH-SHORTENING CYCLE FATIGUE WORKOUT ON FAST STRETCH-SHORTENING CYCLE PERFORMANCE

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    This study examined the effect of a maximal stretch-shortening cycle fatigue workout on the biomechanical performance of rebound jumps that were done 15, 45, 120 and 300 seconds post-fatigue. Thirteen elite level rugby players participated in the study. Rebound jumps were done before and after the workout. All jumps were performed on a sledge and force plate apparatus. Flight time, ground contact time, peak force and leg spring stiffness were the dependent variables. The results indicated that the fatigue workout significantly reduced flight time (p < 0.001), peak force (p < 0.01) and increased contact time (p < 0.05) at the 15 second interval. The efficiency of the stretch-shortening cycle function was reduced. The results also indicate a potentiation effect at the 300-second interval due to a significant increase in peak force and leg stiffness (p < 0.05)

    Towards hardware acceleration of neuroevolution for multimedia processing applications on mobile devices

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    This paper addresses the problem of accelerating large artificial neural networks (ANN), whose topology and weights can evolve via the use of a genetic algorithm. The proposed digital hardware architecture is capable of processing any evolved network topology, whilst at the same time providing a good trade off between throughput, area and power consumption. The latter is vital for a longer battery life on mobile devices. The architecture uses multiple parallel arithmetic units in each processing element (PE). Memory partitioning and data caching are used to minimise the effects of PE pipeline stalling. A first order minimax polynomial approximation scheme, tuned via a genetic algorithm, is used for the activation function generator. Efficient arithmetic circuitry, which leverages modified Booth recoding, column compressors and carry save adders, is adopted throughout the design

    The training and development needs of nurses in Indonesia: paper 3 of 3

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    BACKGROUND: Indonesia's recent economic and political history has left a legacy of widespread poverty and serious health problems, and has contributed to marked inequalities in health care. One means of responding to these challenges has been through a reconsideration of the professional roles of nurses, to enable them to deal with the range and complexity of health problems. However, there are currently a number of obstacles to achieving these aims: there is a serious shortfall in trained nurses; the majority of nurses have only limited education and preparation for the role; and there is no central registration of nurses, which means that it is impossible to regulate either the profession or the standards of care. This study aimed to establish the occupational profiles of each grade of nurse, identify their training and development needs and ascertain whether any differences existed between nurses working in different regions or within hospital or community settings. METHODS: An established and psychometrically valid questionnaire was administered to 524 nurses, covering three grades and coming from five provinces. RESULTS: Significant differences in job profile were found in nurses from different provinces, suggesting that the nature of the role is determined to some degree by the geographical location of practice. The roles of hospital and community nurses, and the different grades of nurse, were fairly similar. All nurses reported significant training needs for all 40 tasks, although these did not vary greatly between grade of nurse. The training needs of nurses from each of the provinces were quite distinct, while those of hospital nurses were greater than those of community nurses. CONCLUSION: The results suggest that the role of the nurse is not as diverse as might be expected, given the different levels of preparation and training and the diversity of their work environments. This may reflect the lack of a central registration system and quality framework, which would normally regulate clinical activities according to qualifications. The differences in training needs between subsections of the sample highlight the importance of identifying skills deficits and using this information to develop customized post-registration education programmes. Together, these results provide a rigorous and reliable approach to defining the occupational roles and continuing education needs of Indonesian nurses

    A review of High Performance Computing foundations for scientists

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    The increase of existing computational capabilities has made simulation emerge as a third discipline of Science, lying midway between experimental and purely theoretical branches [1, 2]. Simulation enables the evaluation of quantities which otherwise would not be accessible, helps to improve experiments and provides new insights on systems which are analysed [3-6]. Knowing the fundamentals of computation can be very useful for scientists, for it can help them to improve the performance of their theoretical models and simulations. This review includes some technical essentials that can be useful to this end, and it is devised as a complement for researchers whose education is focused on scientific issues and not on technological respects. In this document we attempt to discuss the fundamentals of High Performance Computing (HPC) [7] in a way which is easy to understand without much previous background. We sketch the way standard computers and supercomputers work, as well as discuss distributed computing and discuss essential aspects to take into account when running scientific calculations in computers.Comment: 33 page

    Photon statistics from coupled quantum dots

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    We present an optical study of closely-spaced self-assembled InAs/GaAs quantum dots. The energy spectrum and correlations between photons subsequently emitted from a single pair provide not only clear evidence of coupling between the quantum dots but also insight into the coupling mechanism. Our results are in agreement with recent theories predicting that tunneling is largely suppressed between nonidentical quantum dots and that the interaction is instead dominated by dipole-dipole coupling and phonon-assisted energy transfer processes.Comment: 4 pages, 4 figures, to appear in Phys. Re

    The Cut & Enhance method : selecting clusters of galaxies from the SDSS commissioning data

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    We describe an automated method, the Cut & Enhance method (CE) for detecting clusters of galaxies in multi-color optical imaging surveys. This method uses simple color cuts, combined with a density enhancement algorithm, to up-weight pairs of galaxies that are close in both angular separation and color. The method is semi-parametric since it uses minimal assumptions about cluster properties in order to minimize possible biases. No assumptions are made about the shape of clusters, their radial profile or their luminosity function. The method is successful in finding systems ranging from poor to rich clusters of galaxies, of both regular and irregular shape. We determine the selection function of the CE method via extensive Monte Carlo simulations which use both the real, observed background of galaxies and a randomized background of galaxies. We use position shuffled and color shuffled data to perform the false positive test. We have also visually checked all the clusters detected by the CE method. We apply the CE method to the 350 deg^2 of the SDSS (Sloan Digital Sky Survey) commissioning data and construct a SDSS CE galaxy cluster catalog with an estimated redshift and richness for each cluster. The CE method is compared with other cluster selection methods used on SDSS data such as the Matched Filter (Postman et al. 1996, Kim et al. 2001), maxBCG technique (Annis et al. 2001) and Voronoi Tessellation (Kim et al. 2001). The CE method can be adopted for cluster selection in any multi-color imaging surveys.Comment: 62 pages, 32 figures, Accepted for publication in the Astronomical Journal, "the CE galaxy cluster catalog can be downloaded from, http://astrophysics.phys.cmu.edu/~tomo/ce/

    Three-dimensional laser surface imaging and geometric morphometrics resolve frontonasal dysmorphology in schizophrenia.

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    BACKGROUND: Although a role for early developmental disturbance(s) in schizophrenia is postulated, it has proved difficult to identify hard, biological evidence. The brain and face emerge in embryologic intimacy, such that in neurodevelopmental disorders, brain dysmorphogenesis is accompanied by facial dysmorphogenesis. METHODS: Three-dimensional (3D) laser surface imaging was used to capture the facial surface of patients and control subjects in 37 male and 32 female patients who satisfied DSM-IV criteria for schizophrenia in comparison with 58 male and 34 female control subjects. Surface images were analyzed using geometric morphometrics and 3D visualizations to identify domains of facial shape that distinguish patients from control subjects. RESULTS: Both male and, particularly, female patients evidenced significant facial dysmorphology. There was narrowing and reduction of the mid to lower face and frontonasal prominences, including reduced width and posterior displacement of the mouth, lips, and chin; increased width of the upper face, mandible, and skull base, with lateral displacement of the cheeks, eyes, and orbits; and anterior displacement of the superior margins of the orbits. CONCLUSIONS: The frontonasal prominence, which enjoys the most intimate embryologic relationship with the anterior brain and also orchestrates aspects of development in maxillary and mandibular domains, evidences a characteristic topography of dysmorphogenesis in schizophrenia

    Effective representation of RT-LOTOS terms by finite time petri nets

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    The paper describes a transformational approach for the specification and formal verification of concurrent and real-time systems. At upper level, one system is specified using the timed process algebra RT-LOTOS. The output of the proposed transformation is a Time Petri net (TPN). The paper particularly shows how a TPN can be automatically constructed from an RT-LOTOS specification using a compositionally defined mapping. The proof of the translation consistency is sketched in the paper and developed in [1]. The RT-LOTOS to TPN translation patterns formalized in the paper are being implemented. in a prototype tool. This enables reusing TPNs verification techniques and tools for the profit of RT-LOTOS

    A Guyon's canal ganglion presenting as occupational overuse syndrome: A case report

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    <p>Abstract</p> <p>Background</p> <p>Occupational overuse syndrome (OOS) can present as Guyon's canal syndrome in computer keyboard users. We report a case of Guyon's canal syndrome caused by a ganglion in a computer user that was misdiagnosed as OOS.</p> <p>Case presentation</p> <p>A 54-year-old female secretary was referred with a six-month history of right little finger weakness and difficulty with adduction. Prior to her referral, she was diagnosed by her general practitioner and physiotherapist with a right ulnar nerve neuropraxia at the level of the Guyon's canal. This was thought to be secondary to computer keyboard use and direct pressure exerted on a wrist support. There was obvious atrophy of the hypothenar eminence and the first dorsal interosseous muscle. Both Froment's and Wartenberg's signs were positive. A nerve conduction study revealed that both the abductor digiti minimi and the first dorsal interosseus muscles showed prolonged motor latency. Ulnar conduction across the right elbow was normal. Ulnar sensory amplitude across the right wrist to the fifth digit was reduced while the dorsal cutaneous nerve response was normal. Magnetic resonance imaging of the right wrist showed a ganglion in Guyon's canal. Decompression of the Guyon's canal was performed and histological examination confirmed a ganglion. The patient's symptoms and signs resolved completely at four-month follow-up.</p> <p>Conclusion</p> <p>Clinical history, occupational history and examination alone could potentially lead to misdiagnosis of OOS when a computer user presents with these symptoms and we recommend that nerve conduction or imaging studies be performed.</p
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