2,028 research outputs found

    Characterization and semantic modeling of services in multiservice networks

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    The use of the Internet as a global communication infrastructure to support a wide range of multiconstrained applications and services poses new challenges to ISPs regarding network services management and auditing. In this context, the semantic characterization and modeling of services provided to users assumes an essential role in fostering service management automation. Moreover, the semantic and formal description of services allows enhancing the negotiation and interoperability between clients and service providers. This paper reports the first steps toward the definition of an ontology for multiservice networks that eases and systemizes decision support of QoS deployment in ISP infrastructures, according to service levels established in SLAs. Other management tasks such as dynamic service negotiation and configuration, service monitoring and auditing may also benefit from the present ontology proposal

    Axonal stress kinase activation and tau misbehavior induced by kinesin-1 transport defects

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    Many neurodegenerative diseases exhibit axonal pathology, transport defects, and aberrant phosphorylation and aggregation of the microtubule binding protein tau. While mutant tau protein in frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP17) causes aberrant microtubule binding and assembly of tau into filaments, the pathways leading to tau-mediated neurotoxicity in Alzheimer's disease and other neurodegenerative disorders in which tau protein is not genetically modified remain unknown. To test the hypothesis that axonal transport defects alone can cause pathological abnormalities in tau protein and neurodegeneration in the absence of mutant tau or amyloid β deposits, we induced transport defects by deletion of the kinesin light chain 1 (KLC1) subunit of the anterograde motor kinesin-1. We found that upon aging, early selective axonal transport defects in mice lacking the KLC1 protein (KLC1-/-) led to axonopathies with cytoskeletal disorganization and abnormal cargo accumulation. In addition, increased c-jun N-terminal stress kinase activation colocalized with aberrant tau in dystrophic axons. Surprisingly, swollen dystrophic axons exhibited abnormal tau hyperphosphorylation and accumulation. Thus, directly interfering with axonal transport is sufficient to activate stress kinase pathways initiating a biochemical cascade that drives normal tau protein into a pathological state found in a variety of neurodegenerative disorders including Alzheimer's disease.Fil: Falzone, Tomas Luis. Howard Hughes Medical Institute; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Stokin, Gorazd B.. University Psychiatric Hospital; EsloveniaFil: Lillo, Concepción. University of California at San Diego; Estados UnidosFil: Rodrigues, Elizabeth M.. Howard Hughes Medical Institute; Estados UnidosFil: Westerman, Eileen L.. Howard Hughes Medical Institute; Estados UnidosFil: Williams, David S.. University of California at San Diego; Estados UnidosFil: Goldstein, Lawrence S. B.. Howard Hughes Medical Institute; Estados Unido

    Adaptive gossip-based broadcast

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    This paper presents a novel adaptation mechanism that allows every node of a gossip-based broadcast algorithm to adjust the rate of message emission 1) to the amount of resources available to the nodes within the same broadcast group and 2) to the global level of congestion in the system. The adaptation mechanism can be applied to all gossip-based broadcast algorithms we know of and makes their use more realistic in practical situations where nodes have limited resources whose quantity changes dynamically with time without decreasing the reliability.(undefined

    Motor coordination, physical activity and fitness as predictors of longitudinal change in adiposity during childhood

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    The purpose of this study was to examine the influence of motor coordination (MC), physical fitness (PF) and physical activity (PA) on the development of subcutaneous adiposity in a sample of children followed longitudinally from 6 to 10 years of age. Participants were 142 girls and 143 boys. Height, weight, and the triceps and subscapular skinfolds were measured annually between the ages of 6 and 10 years. PA was estimated with the Godin–Shephard questionnaire. MC was evaluated with the Körperkoordination Test für Kinder (KTK) test battery, and PF was assessed with four Fitnessgram tests: curl-ups (CU), push-ups (PU), trunk-lifts (TL) and one mile run/walk (MRW). Hierarchical linear modelling with MC, PF items and PA as predictors of the sum of two skinfolds (SKF) was used. The results showed that boys and girls differed significantly in SKF at baseline (girls: 19.7 mm; boys: 16.6 mm). Three PF items (CU, PU and MRW) and MC had a positive influence on SKF. For each unit improvement in CU, PU, MRW and MC, SKF was reduced by 0.06, 0.04, 0.06 and 0.12 mm, respectively. In conclusion, motor coordination, muscular strength and endurance, and aerobic endurance attenuated the accumulation of subcutaneous adipose tissue during childhood

    DC-DC power converter for high power solar photovoltaic system

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    Worldwide there is an enormous dependence on fossil fuels to produce electricity. Burning fossil fuels results in CO2 emission into the atmosphere, causing a negative environmental impact. In order to mitigate these problems, there is a need to integrate renewable energy sources into the power grid, namely solar photovoltaic (PV) energy. Power electronics converter solutions for solar PV module interface are vast and have advantages and disadvantages depending on the purpose. In addition, when the purpose is efficiency, it is important to consider the choice of the most appropriate power semiconductors. This paper presents a study, sizing, and development of a DC-DC power converter for high-power solar PV applications. In this study, a DC-DC boost interleaved power converter with two arms controlled by an incremental conductance Maximum Power Point Tracking (MPPT) control algorithm is proposed. The MPPT is combined with a Proportional-Integral (PI) controller for individual control of the current on each arm and was applied to extract the maximum power available at the solar PV module for different solar radiation and temperature conditions. The digital control system was implemented in a TMS320F28335 microcontroller from Texas Instruments.This work has been supported by FCT – Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. This work has been supported by the MEGASOLAR Project POCI-01-0247-FEDER-047220. Mr. Luis A. M. Barros is supported by the doctoral scholarship PD/BD/143006/2018 granted by the Portuguese FCT foundation

    Age-related influences on somatic and physical fitness of elite police agents (Influencias de la edad en la aptitud física y somática de los agentes de policía de élite)

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    Background: Elite police officers must be physically fit to perform their job occupational demands but information on the effect of age in their physical fitness and somatic composition is scarce. Our aim is to describe the effect of age on somatic and physical fitness of a Special Police Unit (SPU); and to understand age-related changes. Methods: 117 SPU elements of a total of 218, aged 42.6±4.2 years, were assessed on their somatic (height, weight, circumferences, skinfolds); body composition (BMI, body fat); and physical fitness (maximal, power and endurance strength, aerobic power, and flexibility). T-tests were used for comparing results to other police studies. Regression analysis was used to detect the effect of age for somatic and fitness variable. Results: SPU elements showed a homogeneous and suitable fitness condition. No somatic differences were found along age, but annual age losses were found for physical fitness, namely for strength: left handgrip strength (95%CI -0.70 to -0.12), bench press (95%CI -2.34 to -0.89), squat jump (95%CI -0.70 to -0.12), medicinal ball throw (95%CI -0.62 to -0.25), push-ups (95%CI -1.64 to -0.66), pull-ups (95%CI -0.53 to -0.11), sit-ups (95%CI -1.33 to -0.27), but also on the VO2max (-0.535 to -0.115). Conclusions: Portuguese SPU elements showed a good somatic and physical fitness condition according to the requirements of their profession. Regardless the effect of age they were able to maintain a good somatic fitness and a very good aerobic power along the years. The loss of strength was the most associated with age.4811-99FE-2ECD | Luis Paulo RodriguesN/
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