940 resultados para Closure
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In this paper we use the mixture of topological and measure-theoretic dynamical approaches to consider riddling of invariant sets for some discontinuous maps of compact regions of the plane that preserve two-dimensional Lebesgue measure. We consider maps that are piecewise continuous and with invertible except on a closed zero measure set. We show that riddling is an invariant property that can be used to characterize invariant sets, and prove results that give a non-trivial decomposion of what we call partially riddled invariant sets into smaller invariant sets. For a particular example, a piecewise isometry that arises in signal processing (the overflow oscillation map), we present evidence that the closure of the set of trajectories that accumulate on the discontinuity is fully riddled. This supports a conjecture that there are typically an infinite number of periodic orbits for this system.
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Objective: To document the acute characteristics of swallowing impairment in a group of children post moderate/severe traumatic brain injury (TBI) by means of videofluoroscopy. Participants: Eighteen children with moderate/severe TBI. Main Outcome Measure: Videofluoroscopy at an average of 27.7 days post-injury. Results: Subjects demonstrated a range of dysphagia severity levels: mild-moderate (n = 8), moderate (n = 6), moderate-severe (n = 3), and severe (n = 1) and had a combination of oral and pharyngeal phase characteristics. More specifically; observable features or physiological impairments that were identified included reduced lingual control, hesitancy of tongue movement, repetitive tongue pumping, the presence of aspiration (including silent aspiration), delayed swallow reflex trigger, reduced laryngeal elevation and closure, and reduced peristalsis. Conclusions: These data highlight the diversity of swallowing deficits and dysphagia severity levels in children following TBI and suggest that the former are consistent with a pattern of oropharyngeal impairments.
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The forging characteristics of an Al-Cu-Mg-Si-Sn alloy are examined using it new testing strategy which incorporates a double truncated cone specimen and finite element modelling. This sample geometry produces controlled strain distributions within a single specimen and can readily identify the specific strain required to achieve a specific microstructural event by matching the metallographic data with the strain profiles calculated from finite element software, The friction conditions were determined using the conventional friction ring test, which was evaluated using finite element software. The rheological properties of the alloy, evaluated from compression testing of right cylinders, are similar to the properties of conventional aluminium forgings. A hoop strain develops at the outer diameter of the truncated cones and this leads to pore opening at the outer few millimetres. The porosity is effectively removed when the total strain equals the net compressive strain. The strain profiles that develop in the truncated cones are largely independent of the processing temperature and the strain rate although the strain required for pore closure increases as the forging temperature is reduced. This suggests that the microstructure and the strain rate sensitivity may also be important factors controlling pore behaviour. (C) 2002 Elsevier Science B.V. All rights reserved.
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In the first part of this study, we characterized 24-month-old Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs), their heart weights, and the responses of the isolated left ventricles to electrical stimulation. In the main part of the study, we tested whether the positive inotropic effects of BDF 9198, which prevents the closure of the cardiac sodium channel, were present in senescence and heart failure. Thus, we studied the effects of BDF 9198 on the left ventricle strips of 24-month-old WKY rats (senescence) and SHRs using contractility methods. In comparison with WKY rats, the left ventricles of 24-month-old SHRs were hypertrophied and had prolonged times to peak contraction. BDF 9198 (10(-8) to 10(-6) m) was a positive inotrope on the left ventricles of WKY rats, with a maximum augmenting effect of 122% with BDF 9198 at 10(-7) m. The magnitude of the augmenting effects of BDF 9198 were reduced in SHR heart failure, with a maximum augmenting effect of 26% at 10(-7) m. BDF 9198 at 10(-6) m attenuated the responses of the SHR left ventricle to electrical stimulation. In conclusion, the potential of drugs that prevent closure of the sodium channel as positive inotropes in the treatment of heart failure should be further considered.
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We assayed mtDNA haplotype [300 base pairs (bp) control region] geography and genealogy in the Indo-Pacific tasselfish, Polynemus sheridani from its contiguous estuarine distribution across northern Australia (n = 169). Eight estuaries were sampled from three oceanographic regions (Timor Sea, Gulf of Carpentaria and the Coral Sea) to assess the impact of Pleistocene sea level changes on the historical connectivity among P. sheridani populations. Specifically, we investigated the genetic consequences of disruption to Indian-Pacific Ocean connectivity brought about by the closure of the Torres Strait. Overall there was significant population subdivision among estuaries (F-ST = 0.161, (Phi(ST) = 0.187). Despite a linear distribution, P. sheridani did not show isolation by distance over the entire sampled range because of genetic similarity of estuaries greater than 3000 km apart. However, significant isolation by distance was detected between estuaries separated by less than 3000 km of coastline. Unlike many genetic studies of Indo-Pacific marine species, there was no evidence for an historical division between eastern and western populations. Instead, phylogeographical patterns were dominated by a starlike intraspecific phylogeny coupled with evidence for population expansion in both the Gulf of Carpentaria and the Coral Sea but not the Timor Sea. This was interpreted as evidence for recent west to east recolonization across of northern Australia following the last postglacial marine advance. We argue that although sufficient time has elapsed postcolonization for populations to approach gene flow-drift equilibrium over smaller spatial scales (< 3000 km), the signal of historical colonization persists to obscure the expected equilibrium pattern of isolation by distance over large spatial scales (> 3000 km).
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Cervical auscultation presents as a noninvasive screening assessment of swallowing. Until now the focus of acoustic research in swallowing has been the characterization of swallowing sounds,. However, it may be that the technique is also suitable for the detection of respiratory sounds post swallow. A healthy relationship between swallowing and respiration is widely accepted as pivotal to safe swallowing. Previous investigators have shown that the expiratory phase of respiration commonly occurs prior to and after swallowing. That the larynx is valved shut during swallowing is also accepted. Previous research indicates that the larynx releases valved air immediately post swallow in healthy individuals. The current investigation sought to explore acoustic evidence of a release of subglottic air post swallow in nondysphagic individuals using a noninvasive medium. Fifty-nine healthy individuals spanning the ages of 18 to 60+ years swallowed 5 and 10 milliliters (ml) of thin and thick liquid boluses. Objective acoustic analysis was used to verify presence of the sound and to characterize its morphological features. The sound, dubbed the glottal release sound, was found to consistently occur in close proximity following the swallowing sound. The results indicated that the sound has distinct morphological features and that these change depending on the volume and viscosity of the bolus swallowed. Further research will be required to translate this information to a clinical tool.
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Increasingly, electropalatography (EPG) is being used in speech pathology research to identify and describe speech disorders of neurological origin. However, limited data currently exists that describes normal articulatory segment timing and the degree of variability exhibited by normal speakers when assessed with EPG. Therefore, the purpose of the current investigation was to use the Reading EPG3 system to quantify segmental timing values and examine articulatory timing variability for three English consonants. Ten normal subjects repeated ten repetitions of CV words containing the target consonants /t/, /l/, and /s/ while wearing an artificial palate. The target consonants were followed by the /i/ vowel and were contained in the carrier phrase 'I saw a __'. Mean duration of the approach, closure/constriction, and release phases of consonant articulation were calculated. In addition, inter-subject articulatory timing variability was investigated using descriptive graphs and intra-subject articulatory timing variability was investigated using a coefficient of variation. Results revealed the existence of intersubject variability for mean segment timing values. This could be attributed to individual differences in the suprasegmental features of speech and individual differences in oral cavity size and structure. No significant differences were reported for degree of intra-subject variability between the three sounds for these same phases of articulation. However, when this data set was collapsed, results revealed that the closure/constriction phase of consonant articulation exhibited significantly less intra-subject variability than both the approach and release phases. The stabilization of the tongue against the fixed structure of the hard palate during the closure phase of articulation may have reduced the levels of intra-subject variability.
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A new modeling approach-multiple mapping conditioning (MMC)-is introduced to treat mixing and reaction in turbulent flows. The model combines the advantages of the probability density function and the conditional moment closure methods and is based on a certain generalization of the mapping closure concept. An equivalent stochastic formulation of the MMC model is given. The validity of the closuring hypothesis of the model is demonstrated by a comparison with direct numerical simulation results for the three-stream mixing problem. (C) 2003 American Institute of Physics.
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High-resolution numerical model simulations have been used to study the local and mesoscale thermal circulations in an Alpine lake basin. The lake (87 km(2)) is situated in the Southern Alps, New Zealand and is located in a glacially excavated rock basin surrounded by mountain ranges that reach 3000 m in height. The mesoscale model used (RAMS) is a three-dimensional non-hydrostatic model with a level 2.5 turbulence closure scheme. The model demonstrates that thermal forcing at local (within the basin) and regional (coast-to-basin inflow) scales drive the observed boundary-layer airflow in the lake basin during clear anticyclonic summertime conditions. The results show that the lake can modify (perturb) both the local and regional wind systems. Following sunrise, local thermal circulations dominate, including a lake breeze component that becomes embedded within the background valley wind system. This results in a more divergent flow in the basin extending across the lake shoreline. However, a closed lake breeze circulation is neither observed nor modelled. Modelling results indicate that in the latter part of the day when the mesoscale (coast-to-basin) inflow occurs, the relatively cold pool of lake air in the basin can cause the intrusion to decouple from the surface. Measured data provide qualitative and quantitative support for the model results.
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Consonant imprecision has been reported to be a common feature of the dysarthric speech disturbances exhibited by individuals who have sustained a traumatic brain injury (TBI). Inaccurate tongue placements against the hard palate during consonant articulation may be one factor underlying the imprecision. To investigate this hypothesis, electropalatography (EPG) was used to assess the spatial characteristics of the tongue-to-palate contacts exhibited by three males (aged 23-29 years) with dysarthria following severe TBI. Five nonneurologically impaired adults served as control subjects. Twelve single-syllable words of CV or CVC construction (where initial C = /t, d, S, z, k, g/, V=/i, a/) were read aloud three times by each subject while wearing an EPG palate. Spatial characteristics were analyzed in terms of the location, pattern, and amount of tongue-to-palate contact at the frame of maximum contact during production of each consonant. The results revealed that for the majority of consonants, the patterns and locations of contacts exhibited by the TBI subjects were consistent with the contacts generated by the group of control subjects. One notable exception was one subject's production of the alveolar fricatives in which complete closure across the palate was demonstrated, rather than the characteristic groove configuration. Major discrepancies were also noted in relation to the amount of tongue-to-palate contact exhibited, with two TBI subjects consistently demonstrating increased contacts compared to the control subjects. The implications of these findings for the development of treatment programs for dysarthric speech disorders subsequent to TBI are highlighted.
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The objective of this paper is to definite Historicity in Economic Sciences applying the principles of Entropy and methodological indeterminism. This implies the definition of two kinds of economic universes: one characterized by ergodicity and reversibility of Time and processes and the other by the opposite properties. The first part will deal with the construction of the subject of study and the nature of the proper analysis to these two universes. Taking such dichotomy into account, the second part will examine its implications as regards to the nature of equilibrium, the properties of stability and instability and the closure of the systems.
Resumo:
O principal objetivo deste trabalho foi identificar e caracterizar a evolução diária da Camada Limite Atmosférica (CLA) na Região da Grande Vitória (RGV), Estado do Espírito Santo, Brasil e na Região de Dunkerque (RD), Departamento Nord Pas-de-Calais, França, avaliando a acurácia de parametrizações usadas no modelo meteorológico Weather Research and Forecasting (WRF) em detectar a formação e atributos da Camada Limite Interna (CLI) que é formada pelas brisas marítimas. A RGV tem relevo complexo, em uma região costeira de topografia acidentada e uma cadeia de montanhas paralela à costa. A RD tem relevo simples, em uma região costeira com pequenas ondulações que não chegam a ultrapassar 150 metros, ao longo do domínio de estudos. Para avaliar os resultados dos prognósticos feitos pelo modelo, foram utilizados os resultados de duas campanhas: uma realizada na cidade de Dunkerque, no norte da França, em Julho de 2009, utilizando um sistema light detection and ranging (LIDAR), um sonic detection and ranging (SODAR) e dados de uma estação meteorológica de superfície (EMS); outra realizada na cidade de Vitória – Espírito Santo, no mês de julho de 2012, também usando um LIDAR, um SODAR e dados de uma EMS. Foram realizadas simulações usando três esquemas de parametrizações para a CLA, dois de fechamento não local, Yonsei University (YSU) e Asymmetric Convective Model 2 (ACM2) e um de fechamento local, Mellor Yamada Janjic (MYJ) e dois esquemas de camada superficial do solo (CLS), Rapid Update Cycle (RUC) e Noah. Tanto para a RGV quanto para a RD, foram feitas simulações com as seis possíveis combinações das três parametrizações de CLA e as duas de CLS, para os períodos em que foram feitas as campanhas, usando quatro domínios aninhados, sendo os três maiores quadrados com dimensões laterais de 1863 km, 891 km e 297 km, grades de 27 km, 9 km e 3 km, respectivamente, e o domínio de estudo, com dimensões de 81 km na direção Norte-Sul e 63 km na Leste-Oeste, grade de 1 km, com 55 níveis verticais, até um máximo de, aproximadamente, 13.400 m, mais concentrados próximos ao solo. Os resultados deste trabalho mostraram que: a) dependendo da configuração adotada, o esforço computacional pode aumentar demasiadamente, sem que ocorra um grande aumento na acurácia dos resultados; b) para a RD, a simulação usando o conjunto de parametrizações MYJ para a CLA com a parametrização Noah produziu a melhor estimativa captando os fenômenos da CLI. As simulações usando as parametrizações ACM2 e YSU inferiram a entrada da brisa com atraso de até três horas; c) para a RGV, a simulação que usou as parametrizações YSU para a CLA em conjunto com a parametrização Noah para CLS foi a que conseguiu fazer melhores inferências sobre a CLI. Esses resultados sugerem a necessidade de avaliações prévias do esforço computacional necessário para determinadas configurações, e sobre a acurácia de conjuntos de parametrizações específicos para cada região pesquisada. As diferenças estão associadas com a capacidade das diferentes parametrizações em captar as informações superficiais provenientes das informações globais, essenciais para determinar a intensidade de mistura turbulenta vertical e temperatura superficial do solo, sugerindo que uma melhor representação do uso de solo é fundamental para melhorar as estimativas sobre a CLI e demais parâmetros usados por modelos de dispersão de poluentes atmosféricos.
Resumo:
RESUMO: Com o actual quadro de descentralização de atribuições e competências da administração central para as autarquias locais, na área da educação, os municípios passam a investir cada vez mais na acção educativa ao liderarem e planearem políticas educativas locais mais ou menos explícitas, e, nalguns casos, tentando superar carências que o sistema educativo apresenta. Esta pesquisa tem como problemática compreender o papel do Estado na (re)configuração das políticas de educação, quando a tendência para a mudança, de um Estado-educador para um Estado-regulador, tem por pressuposto o discurso neoliberal de que com ‗menos‘ Estado mas maior accountability se obtêm melhores resultados. Este processo origina uma redefinição no papel e funções do Estado no plano social e económico, provocando constrangimentos e conflitos de poder no que respeita ao seu controlo político, com a redistribuição de poderes entre o Estado e a comunidade, entre o central e o local. É neste contexto de mudança que a presente investigação, que se situa no âmbito da análise das políticas educativas, procura averiguar como e com que meios as autarquias locais concretizam as suas competências na área da educação. A estratégia de investigação concentra-se em uma metodologia qualitativa, com a utilização de um estudo exploratório, em três municípios da Região de Lisboa e Vale do Tejo. As actuais políticas educativas derivam da nova visão na gestão da coisa pública – res publica –, como resultado da nova concepção para o próprio Estado, e dos processos de elaboração das decisões político-educativas. Nesta perspectiva, a descentralização passa a ser um instrumento do poder local que favorece o aumento da autoridade democrática dos actores. Todavia, a governação – governance – supõe uma dinâmica de negociação, até mesmo de regulação entre o Estado, a região, o local, a escola e o mercado, feita para atender à construção do interesse geral, que já não é totalmente definido pelo Estado, mas construído em conjunto com as diversas forças políticas, económicas, educativas e sociais. O estudo permitiu evidenciar que a descentralização é posta em causa pelo Estado central, quando este ‗recentraliza‘ decisões e condiciona o poder local, com o fecho da maioria das escolas do primeiro ciclo e a verticalização dos agrupamentos escolares. Por sua vez, algumas políticas educativas como a ‗Escola a Tempo Inteiro‘ fomentam a desregulação dos vínculos laborais, forçando os municípios a aumentar os seus meios técnicos e humanos e a construírem novas infra-estruturas educativas. As políticas educativas passaram a ser concebidas segundo uma matriz híbrida, que visam a municipalização da educação – do pré-escolar e de todo o ensino básico –, por um lado; e fomentam a situação de ‗quase-mercado‘ com a privatização de sectores e o financiamento de várias instituições – que fornecem serviços na área da educação –, por outro lado. ABSTRACT: With the current framework of decentralization of functions and powers from central government to local authorities, in education, the municipalities are investing each more in educational work in leading educational policies and planning places more or less explicit and in some cases, trying to overcome shortcomings that education system. This research aims to understand the role of the state in the (re) configuration of education policies, when the tendency for the change in a State-Educator for a State-regulator, is the assumption that neo-liberal speech that with 'less' State but with more accountability we achieve better results. This process leads to a redefinition of the role and State functions in socio-economic constraints, resulting in power struggles with regard to its political control, with the redistribution of powers between the state and community, between the central and local. It is in this changing context that the present investigation, which lies in the examination of education policy addresses the question how and by what means the local, materialized their skills in education. The strategy focuses on a qualitative methodology, with the use of an exploratory study in three municipalities of Lisbon and Tagus Valley. The current education policies come from the new vision in the management of public affairs - res publica - as a result of the new design for the State itself, and the process of preparation of educational policy decisions. In this perspective, decentralization becomes an instrument of local government that favours the increase of democratic authority of the actors. However, the governance assumes a dynamic negotiation, even in regulation between the State, region, local authorities, school and market, made to suit the construction of general interest, which is not anymore fully defined by the State, but constructed together with the various political, economic, educational and social forces. The study indicates that decentralization is undermined by the central government when it ‗re-centralize‘ decisions and the local conditions, with the closure of most primary schools and with vertical groupings of schools. In turn, some educational policies such as 'Full Time School' forced the municipalities to increase their technical and human resources, to build new educational infrastructure. The educative policies began to be designed according to a hybrid matrix, which aims the decentralization of education - from pre-school and all the primary school - on one hand, and promote the situation of 'quasi-market' with privatization of sectors and the financing of several institutions - that provide services in education -, on the other hand. RÉSUMÉ: Avec le cadre actuel de décentralisation des fonctions et pouvoirs du gouvernement central aux autorités locales, dans l'éducation, les municipalités investissent de plus en plus dans le travail éducatif dans la conduite des politiques éducatives en mener et en faisant la planification des lieux plus ou moins explicites et, dans certains cas, essayer de remédier aux lacunes que présente l'éducation. Donc, nous voulons avec cette recherche comprendre le rôle de l'Etat dans la (re) configuration des politiques d'éducation, alors que la tendance au changement d‘un État-éducateur pour un État-régulateur, a comme l'hypothèse le discours néo-libéral de que avec «moins» État, mais plus d‘accountability on a des meilleurs résultats. Ce processus conduit à une redéfinition du rôle et des fonctions de l'Etat au plan social et économique, en donnant lieu à des luttes de pouvoir à l'égard de son contrôle politique, avec la redistribution des compétences entre l'État et la collectivité, entre les niveaux central et local. C‘est dans ce contexte changeant que la présente enquête, qui réside dans l‘examen de la politique de l‘éducation aborde la question de savoir comment et par quels moyens le local matérialisé leurs compétences dans l‘éducation. La stratégie est axée sur une méthodologie qualitative, avec l'utilisation d'une étude exploratoire dans trois municipalités de Lisbonne et Vallée du Tage. Les politiques actuelles d'éducation sont tirées de la nouvelle vision dans la gestion des affaires publiques - res publica – à la suite de la nouvelle conception de l'État lui-même, et le processus de préparation des décisions politique-éducatives. Dans cette perspective, la décentralisation devient un instrument de gouvernement local qui favorise l'augmentation de l'autorité démocratique des acteurs. Toutefois, la gouvernance assume une dynamique de négociation, même en matière de réglementation entre l'État, la région, le local, l'école et le marché, faite pour répondre à la construction d'intérêt général, qui n'est pas plus entièrement défini par l'Etat, mais construit en ensemble avec les divers forces politiques, économiques, éducatives et sociales. L‘étude indique que la décentralisation est minée par le gouvernement central quand il ‗re-centralise‘ les décisions et les conditions locales, avec la fermeture de la plupart des écoles du premier cycle et avec des groupements verticaux d‘écoles. À leur tour, certaines politiques éducatives telles que ‗l'école à temps plein‘ forcé les municipalités à accroître leurs ressources techniques et humaines, de construire de nouvelles infrastructures éducatives. Les politiques éducatives ont commencé à être conçues selon une matrice hybride, qui vise à la municipalisation de l'éducation - de l'école maternelle et de toute l'école basique - d'une part ; et de promouvoir la situation de «quasi-marché» avec la privatisation de secteurs et le financement de plusieurs institutions - qui offrent des services dans l'éducation -, d‘autre part.