916 research outputs found

    Structural and optical properties of europium doped zirconia single crystals fibers grown by laser floating zone

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    Yttria stabilized zirconia single crystal fibers doped with europium ions were developed envisaging optical applications. The laser floating zone technique was used in order to grow millimetric high quality single crystal fibers. The as-grown fibers are completely transparent and inclusion free, exhibiting a cubic structure. Under ultraviolet (UV) excitation, a broad emission band appears at 551 nm. The europium doped fibers are translucent with a tetragonal structure and exhibit an intense red emission at room temperature under UV excitation. The fingerprint transition lines between the 5D0 and 7FJ(0–4) multiplets of the Eu3+ ions are observed with the main emission line at ∼ 606 nm due to 5D0→7F2 transition. Photoluminescence excitation and wavelength dependent the photoluminescence spectra confirm the existence of different Eu3+ optical centers. © 2011 American Institute of PhysicsFCT-PTDC/CTM/66195/2006FCT-SFRH/BD/45774/200

    Empiricism and stochastics in cellular automaton modeling of urban land use dynamics

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    An increasing number of models for predicting land use change in regions of rapidurbanization are being proposed and built using ideas from cellular automata (CA)theory. Calibrating such models to real situations is highly problematic and to date,serious attention has not been focused on the estimation problem. In this paper, wepropose a structure for simulating urban change based on estimating land usetransitions using elementary probabilistic methods which draw their inspiration fromBayes' theory and the related ?weights of evidence? approach. These land use changeprobabilities drive a CA model ? DINAMICA ? conceived at the Center for RemoteSensing of the Federal University of Minas Gerais (CSR-UFMG). This is based on aneight cell Moore neighborhood approach implemented through empirical land useallocation algorithms. The model framework has been applied to a medium-size townin the west of São Paulo State, Bauru. We show how various socio-economic andinfrastructural factors can be combined using the weights of evidence approach whichenables us to predict the probability of changes between land use types in differentcells of the system. Different predictions for the town during the period 1979-1988were generated, and statistical validation was then conducted using a multipleresolution fitting procedure. These modeling experiments support the essential logicof adopting Bayesian empirical methods which synthesize various information aboutspatial infrastructure as the driver of urban land use change. This indicates therelevance of the approach for generating forecasts of growth for Brazilian citiesparticularly and for world-wide cities in general

    Body composition comparison between gender in institutionalized elderly

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    Este estudo teve como objetivo averiguar sobre a existência de diferenças entre sexos, da composição corporal de idosos institucionalizados.The purpose of this Study was to compare the body composition differences between gender in institutionalized elderly.info:eu-repo/semantics/publishedVersio

    Do the strength levels predict the motor coordination in young basketball players?

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    O objetivo deste estudo foi averiguar sobre a existência de relação entre os níveis de força e a coordenação motora em basquetebolistas pertencentes ao escalão de sub-18.The aim of this study was to analyse the relation between the strength levels and motor coordination in young basketball players.info:eu-repo/semantics/publishedVersio

    Do the strength levels predict the motor coordination in young basketball players?

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    The aim of this study was to analyse the relation between the strength levels and motor coordination in young basketball players. The sample of this study was composed by 12 basketball players with 15.83 (± 0.55) years old from the U-18 category. The players participate in the inter-regional, national championship round and national cup in 2015/2016 season. The upper limbs strength was evaluated with the push-up exercise, counting the number of repetitions in 30 seconds. The lower limbs strength was evaluated in centimetres with the horizontal jump without preparatory sprint. The motor coordination was evaluated with 6 cones separated by 1,5m in the diagonal. The athletes with ball, skirted the cones and ended with layup finalization, this exercise was measured in seconds. Spearman correlation test was accessed with a significance level of 5%. No significant correlation was observed between upper limbs strength and motor coordination (F =-0,259; p =0.208). However, a negative significant correlation was observed between lower limbs strength and coordination was observed (F =-0,539; p =0,035). Thus, basketball coaches should perform specific strength training seasons intending to improve the motor coordination. Improving strength levels may contribute for motor coordination improvement.info:eu-repo/semantics/publishedVersio

    Effects of triclosan on early development of Solea senegalensis: from biochemical to individual level

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    Harmful effects of triclosan (TCS) have been reported on several organisms; however, effects on early life stages of marine vertebrates are limited. Therefore, the objective of this work was to assess the effects of TCS during early development of the flatfish Solea senegalensis after initial characterization of cholinesterases (ChEs) and determination of selected biochemical markers baseline levels. Characterization of ChEs and determination of biochemical markers baseline levels of cholinergic activity, energy metabolism and oxidative stress were analysed in sole at 3 days after hatching (dah) and at the onset and end of metamorphosis. To assess TCS effects, fish were exposed during 96h to 30-500 μg L-1 TCS until 3 dah. Fish at 13 dah were exposed during 48h to 200-1,500 μg L-1 TCS and maintained until complete metamorphosis. Effects on survival, malformations, length, metamorphosis progression and biochemical markers were evaluated. The main ChE active form present in sole early life stages is acetylcholinesterase and baseline levels of oxidative stress and energy metabolism biomarkers changed according to fish developmental stage. Triclosan induced malformations (EC50 = 180 μg L-1 at 3 dah), decreased growth (95 μg L-1 at 3 dah; 548 μg L-1 at 24 dah) and affected metamorphosis progression (391 μg L-1 at 17 dah). Impairment of antioxidant system was observed, with TCS affecting catalase at the end of metamorphosis test, however, no oxidative damage on lipids was detected. Glutathione S-transferase was the most sensitive endpoint during early larval test (LOEC = 30 μg L-1). Exposure to TCS affected S. senegalensis at individual and sub-individual levels, both at early larval stage and during the critical period of metamorphosis.publishe

    Using multivariate statistics on detection of particular signals during production of knitwear

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    This paper reports the recent developments in the pursuit to correctly locate, identify and distinguish faults during production of weft knitted fabrics. For this purpose a major textile parameter – yarn input tension (YIT) - is analyzed by means of signal processing techniques. An overview of the entire process of gathering the information and fault detection is presented. For the purpose of distinguishing faults, Multivariate statistical methods, namely cluster and discriminant analysis are used, results presented and discussed. Finally, some conclusions are drawn from the obtained results and future developments are addressed.Fundação para a Ciência e a Tecnologia (FCT) - project POSI/SRI/39824/2001

    Surveillance and control of the yarn input tension on circular weft knitting machines : new approaches

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    The Yarn Input Tension - YIT is one of the most important parameters in weft knitting industry. This parameter must be maintained between limits in order to produce knitted fabric without faults. However, YIT is not the only parameter to control and monitor for preventing faults. The knitting elements and the knitting machine itself should be monitored to improve productivity and quality. The monitoring of the YIT can be used to detect the faults and at the same time controlled inside tight limits to prevent machine’s premature stop due to yarn break . This paper will present the recent developments made for monitoring and control the YIT. A surveillance system will be presented, a low cost force sensor will be suggested to substitute the present industrial solutions, and a new actuator for control of the YIT will be introduced.FCT - Fundação para a Ciência e a Tecnologia POSI/SRI/39824/200
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