997 resultados para variable-range hopping
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This study was conducted to determine the effect of increasing age on four shoulder movements and to explore the need for normative data for shoulder range of motion (ROM) in people aged 50 years and older. Forty-one participants were conveniently recruited according to four age categories: 50-59 years, 60-69 years, 70-79 years and 80 years and over. Goniometric measurement of bilateral active and passive ROM for flexion, abduction, internal rotation and external rotation was analysed using paired sample t-tests and compared with the norms of the American Academy of Orthopaedic Surgeons (AAOS) using one sample t-tests. Passive ROM was greater than active ROM for all movements (p
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Most external assessments of cervical range of motion assess the upper and lower cervical regions simultaneously. This study investigated the within and between days reliability of the clinical method used to bias this movement to the upper cervical region, namely measuring rotation of the head and neck in a position of full cervical flexion. Measurements were made using the Fastrak measurement system and were conducted by one operator. Results indicated high levels of within and between days repeatability (range of ICC2,1 values: 0.85-0.95). The ranges of axial rotation to right and left, measured with the neck positioned in full flexion, were approximately 56% and 50%, respectively of total cervical rotation, which relates well to the proportional division of rotation in the upper and lower cervical regions. These results suggest that this method of measuring rotation would be appropriate for use in subject studies where movement dysfunction is present in the upper cervical region, such as those with cervicogenic headache. (C) 2003 Elsevier Science Ltd. All rights reserved.
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An equivalent unit cell waveguide approach (WGA) to designing 4 multilayer microstrip reflectarray of variable size patches is presented. In this approach, a normal incidence of a plane wave on an infinite periodic array of radiating elements is considered to obtain reflection coefficient phase curves for the reflectarray's elements. It is shown that this problem is equivalent to the problem of reflection of the dominant TEM mode in a waveguide with patches interleaved by layers of dielectric. This waveguide problem is solved using a field matching technique and a method of moments (MoM). Based on this solution, a fast computer algorithm is developed to generate reflection coefficient phase curves for a multilayer microstrip patch reflectarray. The validity of the developed algorithm is tested against alternative approaches and Agilent High Frequency Structure Simulator (HFSS). Having confirmed the validity of the WGA approach, a small offset feed two-layer microstrip patch array is designed and developed. This reflectarray is tested experimentally and shows good performance.
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Purpose : Myelomeningocele is a complex disease often complicated by obesity for reasons not well understood. The objectives of this study were to determine body composition and energy expenditure of children with MMC. Methods : Resting energy expenditure (REE), body composition and anthropometry were measured in 19 children with MMC (12 M, 7 F). Total energy expenditure (TEE) was estimated using a 3-day activity record. Energy intake (EI) was measured in seven children (5 M, 2 F) with MMC. Data were then compared with predicted values. Results : Mean REE ( n = 19) was 4680 ±1452 kJ/day (96.1 ±18.1% of predicted REE). The range was large (45.8-125.7% of predicted REE). TEE ( n = 7) was 4344 ±2376 kJ/day, hence only 73 34% of predicted TEE. EI ( n = 7) was 6560 ±1329 kJ/day, approximating a normal energy requirement. Overall, BCM was lower than expected values. Conclusions : REE in children with MMC is variable when compared to predicted values. TEE was found to be lower in children with MMC than predicted values and EI was similar to predicted values in this group of seven children. BCM is reduced in children with MMC when compared to expected values.
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The entire internal transcribed spacer ( ITS) region, including the 5.8S subunit of the nuclear ribosomal DNA ( rDNA), was sequenced by direct double-stranded sequencing of polymerase chain reaction (PCR) amplified fragments. The study included 40 Sporobolus ( Family Poaceae, subfamily Chloridoideae) seed collections from 14 putative species ( all 11 species from the S. indicus complex and three Australian native species). These sequences, along with those from two out-group species [ Pennisetum alopecuroides ( L.) Spreng. and Heteropogon contortus ( L.) P. Beauv. ex Roemer & Schultes, Poaceae, subfamily Panicoideae], were analysed by the parsimony method (PAUP; version 4.0b4a) to infer phylogenetic relationships among these species. The length of the ITS1, 5.8S subunit and ITS2 region were 222, 164 and 218 base pairs ( bp), respectively, in all species of the S. indicus complex, except for the ITS2 region of S. diandrus P. Beauv. individuals, which was 217 bp long. Of the 624 characters included in the analysis, 245 ( 39.3%) of the 330 variable sites contained potential phylogenetic information. Differences in sequences among the members of the S. pyramidalis P. Beauv., S. natalensis (Steud.) Dur & Schinz and S. jacquemontii Kunth. collections were 0%, while differences ranged from 0 to 2% between these and other species of the complex. Similarly, differences in sequences among collections of S. laxus B. K. Simon, S. sessilis B. K. Simon, S. elongatus R. Br. and S. creber De Nardi were 0%, compared with differences of 1-2% between these four species and the rest of the complex. When comparing S. fertilis ( Steud.) Clayton and S. africanus (Poir.) Robyns & Tourney, differences between collections ranged from 0 to 1%. Parsimony analysis grouped all 11 species of the S. indicus complex together, indicating a monophyletic origin. For the entire data set, pair-wise distances among members of the S. indicus complex varied from 0.00 to 1.58%, compared with a range of 20.08-21.44% among species in the complex and the Australian native species studied. A strict consensus phylogenetic tree separated 11 species of the S. indicus complex into five major clades. The phylogeny, based on ITS sequences, was found to be congruent with an earlier study on the taxonomic relationship of the weedy Sporobolus grasses revealed from random amplified polymorphic DNA ( RAPD). However, this cladistic analysis of the complex was not in agreement with that created on past morphological analyses and therefore gives a new insight into the phylogeny of the S. indicus complex.
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We investigate nonclassical Stokes-operator variances in continuous-wave polarization-squeezed laser light generated from one and two optical parametric amplifiers. A general expression of how Stokes-operator variances decompose into two-mode quadrature operator variances is given. Stokes parameter variance spectra for four different polarization-squeezed states have been measured and compared with a coherent state. Our measurement results are visualized by three-dimensional Stokes-operator noise volumes mapped on the quantum Poincare sphere. We quantitatively compare the channel capacity of the different continuous-variable polarization states for communication protocols. It is shown that squeezed polarization states provide 33% higher channel capacities than the optimum coherent beam protocol.
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We generate a pair of entangled beams from the interference of two amplitude squeezed beams. The entanglement is quantified in terms of EPR paradox and inseparability criteria, with both results clearly beating the standard quantum limit. We experimentally analyze the effect of decoherence on each criterion and demonstrate qualitative differences. We also characterize the number of required and excess photons present in the entangled beams and provide contour plots of the efficacy of quantum information protocols in terms of these variables.
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We report the experimental demonstration of quantum teleportation of the quadrature amplitudes of a light field. Our experiment was stably locked for long periods, and was analyzed in terms of fidelity F and with signal transfer T-q=T++T- and noise correlation V-q=Vinparallel to out+Vinparallel to out-. We observed an optimum fidelity of 0.64+/-0.02, T-q=1.06+/-0.02, and V-q=0.96+/-0.10. We discuss the significance of both T-q>1 and V-q
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We generate and characterize continuous variable polarization entanglement between two optical beams. We first produce quadrature entanglement, and by performing local operations we transform it into a polarization basis. We extend two entanglement criteria, the inseparability criteria proposed by Duan et al (2000 Phys. Rev. Lett. 84 2722) and the Einstein–Podolsky–Rosen (EPR) paradox criteria proposed by Reid and Drummond (1988 Phys. Rev. Lett. 60 2731), to Stokes operators; and use them to characterize the entanglement. Our results for the EPR paradox criteria are visualized in terms of uncertainty balls on the Poincaré sphere. We demonstrate theoretically that using two quadrature entangled pairs it is possible to entangle three orthogonal Stokes operators between a pair of beams, although with a bound √3 times more stringent than for the quadrature entanglement.
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Pili of pathogenic Neisseria are major virulence factors associated with adhesion, cytotoxicity, twitching motility, autoaggregation, and DNA transformation. Pili are modified posttranslationally by the addition of phosphorylcholine. However, no genes involved in either the biosynthesis or the transfer of phosphorylcholine in Neisseria meningitidis have been identified. In this study, we identified five candidate open reading frames (ORFs) potentially involved in the biosynthesis or transfer of phosphorylcholine to pilin in N. meningitidis. Insertional mutants were constructed for each ORF in N. meningitidis strain C311#3 to determine their effect on phosphorylcholine expression. The effect of the mutant ORFs on the modification by phosphorylcholine was analyzed by Western analysis with phosphorylcholine-specific monoclonal antibody TEPC-15. Analysis of the mutants showed that ORF NMB0415, now defined as pptA (pilin phosphorylcholine transferase A), is involved in the addition of phosphorylcholine to pilin in N. meningitidis. Additionally, the phase variation (high frequency on-off switching of expression) of phosphorylcholine on pilin is due to changes in a homopolymeric guanosine tract in pptA.
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The synthesis of helium in the early Universe depends on many input parameters, including the value of the gravitational coupling during the period when the nucleosynthesis takes place. We compute the primordial abundance of helium as function of the gravitational coupling, using a semi-analytical method, in order to track the influence of G in the primordial nucleosynthesis. To be specific, we construct a cosmological model with varying G, using the Brans-Dicke theory. The greater the value of G at nucleosynthesis period, the greater the predicted abundance of helium. Using the observational data for the abundance of primordial helium, constraints for the time variation of G are established.
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A absorção de água por carcaças de frango na etapa de pré-resfriamento da linha abate representa uma característica de qualidade importante relacionada ao rendimento do produto final. Uma forma de manter o padrão de qualidade de um produto é garantir que as etapas do processo sejam estáveis e replicáveis. Ao empregar o Controle Estatístico de Processo (CEP) é possível obter estabilidade e melhorias nos processos, por meio da redução da variabilidade. Neste contexto, o objetivo deste trabalho foi a aplicação de gráficos de controle, análise de correlação, estatística descritiva, testes de hipóteses e regressão linear múltipla na linha de abate de um abatedouro-frigorífico de aves para monitorar a variabilidade da absorção de água pelas carcaças de frango após a etapa de pré-resfriamento. Como resultado, verificou-se que o teor de absorção de água das carcaças de frango apresentou elevada variabilidade, sendo que 10% (8/80) das carcaças apresentaram absorção de água superior ao limite de 8% definido pela legislação brasileira. Do total de 16 variáveis de entrada analisadas, as mais impactantes no teor de absorção de água foram o “tempo de retenção da carcaça no pré-chiller” e o “tempo de espera da carcaça após a etapa de gotejamento”. Entretanto, o modelo de regressão obtido apresentou baixa correlação (R²=0,16) que foi associada à elevada variabilidade da variável-resposta. Os resultados da estatística descritiva demonstraram que as variáveis de entrada também apresentaram elevada variabilidade, com coeficiente de variação entre 7,95 e 63,5%. Verificou-se, pela análise dos gráficos de controle de medida individual e da amplitude móvel, que 15 das 16 variáveis de entrada se apresentaram fora de controle estatístico assim como a variável-resposta. Baseado no fluxograma e na descrição das etapas da linha de abate, previamente realizados, atribuiu-se à falta de padronização na condução das etapas e de procedimentos para o controle de qualidade das operações na linha de abate como fatores relevantes que poderiam estar associados à presença de causas especiais no processo. Concluiu-se que para reduzir a elevada variabilidade das variáveis e eliminar as causas especiais presentes são necessários ajustes operacionais para, dessa forma, obter um processo mais estável e mais uniforme garantindo o padrão de qualidade das carcaças de frango em relação ao teor de absorção de água.
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O câncer de mama é a principal neoplasia maligna que acomete o sexo feminino no Brasil. O câncer de mama é hoje uma doença de extrema importância para a saúde pública nacional, motivando ampla discussão em torno das medidas que promova o seu diagnóstico precoce, a redução em sua morbidade e mortalidade. A presente pesquisa possui três objetivos, cujos resultados encontram-se organizados em artigos. O primeiro objetivo buscou analisar a completude dos dados do Sistema de Informação de Mortalidade sobre os óbitos por câncer de mama em mulheres no Espírito Santo, Sudeste e Brasil (1998 a 2007). Realizou-se um estudo descritivo analítico baseado em dados secundários, onde foi analisado o número absoluto e percentual de não preenchimento das variáveis nas declarações de óbitos. Adotou-se escore para avaliar os graus de não completude. Os resultados para as variáveis sexo e idade foram excelentes tanto para o Espírito Santo, Sudeste e Brasil. O preenchimento das variáveis raça/cor, grau de escolaridade e estado civil apresentam problemas no Espírito Santo. Enquanto no Sudeste e Brasil as variáveis raça/cor e escolaridade têm tendência decrescente para a não completude, no Espírito Santo a tendência se mantém estável. Para a variável estado civil, a não completude tem tendência crescente no Estado do Espírito Santo. O segundo objetivo foi analisar a evolução das taxas de mortalidade por câncer de mama, em mulheres no Espírito Santo no período de 1980 a 2007. Estudo de série temporal, cujos dados sobre óbitos foram obtidos do Sistema de Informação de Mortalidade e as estimativas populacionais segundo idade e anos-calendário, do Instituto Brasileiro Geografia e Estatística. Os coeficientes específicos 9 de mortalidade, segundo faixa etária, foram calculados anualmente. A análise de tendência foi realizada por meio da padronização das taxas de mortalidade pelo método direto, em que a população do senso IBGE-2000, foi considerada padrão. No período de estudo, ocorreram 2.736 óbitos por câncer de mama. O coeficiente de mortalidade neste período variou de 3,41 a 10,99 por 100.000 mulheres. Os resultados indicam que há tendência de mortalidade por câncer de mama ao longo da série (p=0,001 com crescimento de 75,42%). Todas as faixas etárias a partir de 30 anos apresentaram tendência de crescimento da mortalidade estatisticamente significante (p=0,001). Os percentuais de crescimento foram aumentando, segundo as idades mais avançadas, sendo 48,4% na faixa de 40 a 49 anos, chegando a 92,3%, na faixa de 80 anos e mais. O terceiro objetivo foi realizar a análise espacial dos óbitos em mulheres por câncer de mama no estado do Espírito Santo, nos anos de 2003 a 2007, com análise das correlações espaciais dessa mortalidade e componentes do município. O cenário foi o Estado do Espírito Santo, composto por 78 municípios. Para análise dos dados, utilizou-se a abordagem bayesiana (métodos EBest Global e EBest Local) para correção de taxas epidemiológicas. Calculou-se o índice I de Moran, para dependência espacial em nível global e a estatística Moran Local. As maiores taxas estão concentradas em 19 municípios pertencentes às Microrregiões: Metropolitana (Fundão, Vitória, Vila Velha, Viana, Cariacica e Guarapari), Metrópole Expandida Sul (Anchieta, Alfredo Chaves), Pólo Cachoeiro (Vargem Alta, Rio Novo do Sul, Mimoso do Sul, Cachoeiro de Itapemirim, Castelo, Jerônimo Monteiro, Bom Jesus do Norte, Apiacá e Muqui) e Caparaó (Alegre e São José do Calçado). Os resultados da Estimação Bayesiana (Índice de Moran) dos óbitos por câncer de mama em mulheres ocorridos no estado do Espírito Santo, segundo os dados brutos e 10 ajustados indicam a existência de correlação espacial significativa para o mapa Local (I = 0,573; p = 0,001) e Global (I = 0,118; p = 0,039). Os dados brutos não apresentam correlação espacial (I = 0,075; p = 0,142).
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Composites of styrene–butadiene–styrene (SBS) block copolymer with multiwall carbon nanotubes were processed by solution casting to investigate the influence of filler content, the different ratios of styrene/butadiene in the copolymer and the architecture of the SBS matrix on the electrical, mechanical and electro-mechanical properties of the composites. It was found that filler content and elastomer matrix architecture influence the percolation threshold and consequently the overall composite electrical conductivity. Themechanical properties aremainly affected by the styrene and filler content. Hopping between nearest fillers is proposed as the main mechanism for the composite conduction. The variation of the electrical resistivity is linear with the deformation. This fact, together with the gauge factor values in the range of 2–18, results in appropriate composites to be used as (large) deformation sensors.