2,214 research outputs found

    An ant colony optimization approach for maximizing the lifetime of heterogeneous wireless sensor networks

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    Maximizing the lifetime of wireless sensor networks (WSNs) is a challenging problem. Although some methods exist to address the problem in homogeneous WSNs, research on this problem in heterogeneous WSNs have progressed at a slow pace. Inspired by the promising performance of ant colony optimization (ACO) to solve combinatorial problems, this paper proposes an ACO-based approach that can maximize the lifetime of heterogeneous WSNs. The methodology is based on finding the maximum number of disjoint connected covers that satisfy both sensing coverage and network connectivity. A construction graph is designed with each vertex denoting the assignment of a device in a subset. Based on pheromone and heuristic information, the ants seek an optimal path on the construction graph to maximize the number of connected covers. The pheromone serves as a metaphor for the search experiences in building connected covers. The heuristic information is used to reflect the desirability of device assignments. A local search procedure is designed to further improve the search efficiency. The proposed approach has been applied to a variety of heterogeneous WSNs. The results show that the approach is effective and efficient in finding high-quality solutions for maximizing the lifetime of heterogeneous WSNs

    ARCHERY TRAINING IMPROVE POSTURAL CONTROL IN YOUNG CHILDREN

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    Exercise training might be beneficial for postural control (PC) during exercise and daily activities. The purpose of the study was to examine the effects of an eight-week archery training program on PC in young children during the standard, aiming, and archery shooting standing posture

    POSTURAL CONTROL IN ELITE ARCHERS DURING SHOOTING

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    Archery is described as a static sport requiring fine movement control and proper endurance strength of the upper body (Soylu, Ertan, & Korkusuz, 2006).To investigate the differences of postural control (PC) between elite and general collegiate archers during static and shooting conditions

    Environment-induced dynamical chaos

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    We examine the interplay of nonlinearity of a dynamical system and thermal fluctuation of its environment in the ``physical limit'' of small damping and slow diffusion in a semiclassical context and show that the trajectories of c-number variables exhibit dynamical chaos due to the thermal fluctuations of the bath.Comment: Revtex, 4 pages and 4 figure

    Breakdown of correspondence in chaotic systems: Ehrenfest versus localization times

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    Breakdown of quantum-classical correspondence is studied on an experimentally realizable example of one-dimensional periodically driven system. Two relevant time scales are identified in this system: the short Ehrenfest time t_h and the typically much longer localization time scale T_L. It is shown that surprisingly weak modification of the Hamiltonian may eliminate the more dramatic symptoms of localization without effecting the more subtle but ubiquitous and rapid loss of correspondence at t_h.Comment: 4 pages, 5 figures, replaced with a version submitted to PR

    THE RELATIONSHIPS BETWEEN THE FUNCTIONAL MOVEMENT SCREEN AND THE POSTURAL STABILITY IN COLLEGIATE ATHLETES

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    The Functional Movement Screen (FMS) is a tool developed recently not only to aid in the prevention of injury by objectively measuring dysfunction and asymmetries within movement patterns, but also could be used as a baseline for further strength, conditioning, or athletic development. The purpose of this study was to examine the relationships between the scores of FMS in relation to the postural stability (PS) in collegiate athletes. A total of 30 male, basketball athletes volunteered to join this study. The PS were measured by the Biodex Balance System as the displacements of the center of foot pressure (COP) in the limits of stability. The score of FMS were evaluated by one certified professional experts. The results showed that the score of FMS has relation to the performance of the PS in a certain extent, especially in the FMS-shoulder mobility to the LOS overall level 6 (r=.26-.41), in the FMS-active straight leg raise to the LOS forward, backward, right, right-back level 6 (r=.30-.39), and in the FMS-trunk stability push-up to the LOS right, back, and right-forward. It was concluded that the score of FMS might be used to evaluate and/or predict the performance of the PS in young, collegiate athletes

    Kir5.1 regulates Nedd4-2-mediated ubiquitination of Kir4.1 in distal nephron.

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    Kir4.1/5.1 heterotetramer participates in generating the negative cell membrane potential in distal convoluted tubule (DCT) and plays a critical role in determining the activity of Na-Cl cotransporter (NCC). Kir5.1 contains a phosphothreonine motif at its COOH terminus (AA249-252). Coimmunoprecipitation showed that Nedd4-2 was associated with Kir5.1 in HEK293 cells cotransfected with Kir5.1 or Kir4.1/Kir5.1. GST pull-down further confirmed the association between Nedd4-2 and Kir5.1. Ubiquitination assay showed that Nedd4-2 increased the ubiquitination of Kir4.1/Kir5.1 heterotetramer in the cells cotransfected with Kir4.1/Kir5.1, but it has no effect on Kir4.1 or Kir5.1 alone. Patch-clamp and Western blot also demonstrated that coexpression of Nedd4-2 but not Nedd4-1 decreased K currents and Kir4.1 expression in the cells cotransfected with Kir4.1 and Kir5.1. In contrast, Nedd4-2 fails to inhibit Kir4.1 in the absence of Kir5.1 or in the cells transfected with the inactivated form of Nedd4-2 (Nedd4-2C821A). Moreover, the mutation of TPVT motif in the COOH terminus of Kir5.1 largely abolished the association of Nedd4-2 with Kir5.1 and abolished the inhibitory effect of Nedd4-2 on K currents in HEK293 cells transfected with Kir4.1 and Kir5.1 mutant (Kir5.1T249A). Finally, the basolateral K conductance in the DCT and Kir4.1 expression is significantly increased in the kidney-specific Nedd4-2 knockout or in Kir5.1 knockout mice in comparison to their corresponding wild-type littermates. We conclude that Nedd4-2 binds to Kir5.1 at the phosphothreonine motif of the COOH terminus, and the association of Nedd4-2 with Kir5.1 facilitates the ubiquitination of Kir4.1, thereby regulating its plasma expression in the DCT

    Bacterial wilt of sweet potato caused by Ralstonia solanacearum in Taiwan

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    During the last decade, a new bacterial disease has impaired the yield of vegetable sweet potato (30-80%) in Taiwan. Infected plants developed stunting, root and stem rot, vascular discoloration and wilting. Ten bacterial isolates that caused the same symptoms in sweet potatoes after inoculation were reisolated and classified as Ralstonia solanacearum phylotype I biovar 4 based on physical and molecular analyses. Moreover, these isolates also caused wilting in convolvulaceous, solanaceaous and cruciferous plants. This report is the first of bacterial wilt of sweet potato caused by R. solanacearum in Taiwan

    Attributions and Outcomes of Customer Misbehavior

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    The purpose of this study is to determine which attribution dimensions concerning dysfunctional other-customer misbehavior most influence customer dissatisfaction toward a service firm. Our research hypotheses were tested using a 2 (Controllability: controllable versus uncontrollable) x 2 (Stability: unstable versus stable) x 2 (Globality: specific versus global) experimental design in a hypothetical restaurant context. Our empirical results demonstrate that when customers feel that the other-customer's misbehavior can be controlled by the firm (i.e., controllability attributions) or is likely to recur (i.e., stability attributions), they render unfavorable service evaluations toward that firm. However, these harmful effects may be mitigated if the customer believes that the same type of dysfunctional customer behavior also occurs during service encounters in other firms (i.e., globality attributions). With a view to diminishing the unsatisfactory experience of other-customer failure, the service organizations need to: (1) act as "police officers" to ensure that their customers behave appropriately; (2) have policies and procedures in place to manage their guests' behavior so as to reduce the recurrence of other-customer failure; and (3) consider communications intended to enhance attributions of globality following an other-customer failure, that will help to buffer the negative impact of controllability and stability attributions on satisfaction and behavioral reactions with the firm. This is the first time that controllability, stability, and globality attributions are clearly shown to be part of the process by which customers transfer their negative response to other-customer misbehavior to the organization

    Expression of Pseudomonas amyloderamosa isoamylase gene in Saccharomyces cerevisiae

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    Isoamylase gene (iso) of Pseudomonas amyloderamosa was amplified by polymerase chain reaction and cloned into Saccharomyces cerevisiae vectors under the control of alcohol dehydrogenase gene and glyceraldehyde-3-phosphate dehydrogenase gene promoters. The signal sequence of iso gene was also replaced with that of Schwanniomyces occidentalis alpha-amylase gene. The extracellular isoamylase activity of transformed Sacc. cerevisiae could reach 86 U ml(-1) after a 4-days cultivation
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