979 resultados para Celle in silicio cristallino, Riflettanza, Testurizzazione, Light trapping


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Effect of environmental factors on the growth of the Chlorella vulgaris was studied. C. vulgaris was cultivated in sterilized natural seawater enriched with F/2-Si medium. Then grow in bucket, tub and photobioreactor (PBR) in outdoor condition. The daily routine work consisted of culture checkups of optical density, biomass gains, atmosphere lux, culture lux, atmosphere temperature and culture temperature were recorded. The highest biomass yields were (3.0 μg/ml-1) in December and (2.01 μg/ml-1) in November in PBR. The highest deviation was in atmosphere lux in time 8:30 (± 117.7) and lowest deviation was in atmosphere temperature in time 15:00 (± 1.0499). Optical density (OD) indicated that the best growth of C. vulgaris in outdoor condition was obtained in 650 lux and also it increased with increasing amount of lux. Tub report of C. vulgaris showed different growing behaviors at the various concentration of light and at the different temperatures. Algal production in outdoor PBR is relatively inexpensive, but is only suitable for a few, fast-growing specie. Finally, this fact is noteworthy that in outdoor conditions, temperature and light have important role in growth of C. vulgaris in present study.

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This article focuses on the connections between built heritage-making and socioeconomic renewal in declining rural areas. Drawing on fieldwork in twelve rural villages in eastern Portugal, it sheds light on the outcomes of a State-led programme, the objectives of which were to renovate the historic built fabric and generate tourism revenue for a region with declining population levels. Overall, the programme was successful in terms of preservation / conservation of monuments and the built fabric, but failed to stimulate the anticipated social and economic development. The conclusion is that the making of heritage spaces is not the remedy for the economic and demographic ills of rural areas, notwithstanding the positive effect that such measures may have in certain cases.

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Stress serves as an adaptive mechanism and helps organisms to cope with life-threatening situations. However, individual vulnerability to stress and dysregulation of this system may precipitate stress-related disorders such as depression. The neurobiological circuitry in charge of dealing with stressors has been widely studied in animal models. Recently our group has demonstrated a role for lysophosphatidic acid (LPA) through the LPA1 receptor in vulnerability to stress, in particular the lack of this receptor relates to robust decrease of adult hippocampal neurogenesis and induction of anxious and depressive states. Nevertheless, the specific abnormalities in the limbic circuit in reaction to stress remains unclear. The aim of this study is to examine the differences in the brain activation pattern in the presence or absence of LPA1 receptor after acute stress. For this purpose, we have studied the response of maLPA1-null male mice and normal wild type mice to an intense stressor: Tail Suspension Test. Activation induced by behaviour of brain regions involved in mood regulation was analysed by stereological quantification of c-Fos immunoreactive positive cells. We also conducted multidimensional scaling analysis in order to unravel coativation between structures. Our results revealed hyperactivity of stress-related structures such as amygdala and paraventricular nucleus of the hypothalamus in the knockout model and different patterns of coactivation in both genotypes using a multidimensional map. This data provides further evidence to the engagement of the LPA1 receptors in stress regulation and sheds light on different neural pathways under normal and vulnerability conditions that can lead to mood disorders.

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Prevention scientists have called for more research on the factors affecting the implementation of substance use prevention programs. Given the lack of literature in this area, coupled with evidence that children as early as elementary school engage in substance use, the purpose of this study was to identify the factors that influence the implementation of substance use prevention programs in elementary schools. This study involved a mixed methods approach comprised of a survey and in-person interviews. Sixty-five guidance counselors and teachers completed the survey, and 9 guidance counselors who completed the survey were interviewed individually. Correlation analyses and hierarchical multiple regression were conducted. Quantitative findings revealed ease of implementation most frequently influenced program implementation, followed by beliefs about the program’s effectiveness. Qualitative findings showed curriculum modification as an important theme, as well as difficulty of program implementation. The in-person interviews also shed light on three interrelated themes influencing program implementation – The Wheel, time, and scheduling. Results indicate the majority of program providers modified the curriculum in some way. Implications for research, policy, and practice are discussed, and areas for future research are suggested.

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The purpose of this study was to quantify the metabolic equivalents (METs) of resistance exercise in obese patients with type 2 diabetes (T2DM) and healthy young subjects and to evaluate whether there were differences between sessions executed at low- versus high-intensity resistance exercise. Twenty obese patients with T2DM (62.9±6.1 years) and 22 young subjects (22.6±1.9 years) performed two training sessions: one at vigorous intensity (80% of 1-repetition maximum (1RM)) and one at moderate intensity (60% of 1RM). Both groups carried out three strength exercises with a 2-day recovery between sessions. Oxygen consumption was continuously measured 15 min before, during and after each training session. Obese T2DM patients showed lower METs values compared with young healthy participants at the baseline phase (F= 2043.86; P<0.01), during training (F=1140.59; P<0.01) and in the post-exercise phase (F=1012.71; P<0.01). No effects were detected in the group x intensity analysis of covariance. In this study, at both light-moderate and vigorous resistance exercise intensities, the METs value that best represented both sessions was 3 METs for the obese elderly T2DM patients and 5 METs for young subjects.

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Dry or imbibed seeds of the negatively photoblastic burr burying subterranean clover cv. ‘Seaton Park’ were treated with dark or with red, blue or white light to evaluate the effects of light on seed germination. Dry seeds treated with constant white light, red light or blue light during 8 days and subsequently incubated in dark had final germination and duration of germination reduced, and the distribution of germination changed from highly asymmetric to symmetric respectively. Imbibing seeds incubated under constant blue or white light had final germination strongly reduced seven days after sowing (7.3% and 50.1% of the germination under dark) with significant differences between them. After transferral to dark, true complete recovery of germination of seeds treated with white light was observed 19 days after sowing, but only partial recovery in seeds treated with blue light. Results of dry and imbibed seeds are consistent with no activity of phytochromes, as expected in negatively photoblastic seeds. Results of dry seeds are seemingly contradictory because total germination data imply the inactivity of red and blue light photoreceptors, the opposite being implied by duration and shape of germination. A tentative hypothetical solution for the contradiction is presented. Results of imbibed seeds are fully consistent with cryptochromes but not with phototropins mediation of responses to light of seed germination in ‘Seaton Park’. The ecological and adaptive significance of such responses are discussed in the framework of light attenuation in soil and the requirement and ability of subterranean clover ‘Seaton Park’ to bury seeds.

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The objective of this paper was to determine changes in the spatial distribution of tree species in a logged compared to an unlogged forest of the Tapajos National Forest in the municipality of Belterra, State of Para, Brazil, over an eight-year period. The distribution pattern was determined for trees> 5 cm dbh and, also, for trees > 30 cm dbh. The relationship (a quadrate method) discussed by McGinnis was selected to be used in this study. Forty-seven percent of species with trees > 5 cm dbh showed clumped distribution in the studied forests. Geissospermwn sericeunz Benth & Hook., Minquartia guianensis Aubl., Poureria bilocularis (H. Winkler) Bachni, Protium guacayantan Cuatrec, Sclerolobium chrysophyllunz Poepp. et Endl. and the Sapotaceae family (9 species) occurred in clumps of small trees (5 cm 5 dbh < 30 cm) and big trees (dbh > 30 cm) in both the logged and undisturbed forest. Trees in all sizes of these species certainly have aggregation characteristics in different light condition's during the whole growth-cycle. Only Sclerolobium cizzysophylltan out of fourteen species that occurred aggregated in all forest conditions was light demanding. The shade-tolerant Lecythis lurida (Miers) Mori and Manilkara huberi (Ducke) Stand!. showed also aggregated distribution for small and big trees in the unlogged forest. An aggregated distribution is not always directly correlated to abundance, considering that most of the clumped species had less than seven trees per hectare.

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We report here on some aspects of the acetylation in LiCl/N,N-dimethylacetamide, DMAc, of untreated and mercerized sisal cellulose, hereafter designated as sisal and M-sisal, respectively. Fiber mercerization by NaOH solution has resulted in the following changes: 29.9% decrease in the index of crystallinity; 16.2% decrease in the degree of polymerization and 9.3% increase in α-cellulose content. A light scattering study of solutions of sisal, M-sisal, microcrystalline and cotton celluloses in LiCl/DMAc has shown that they are present as aggregates, with (an apparent) average aggregation numbers of 5.2, 3.2, 9.8, and 35.3, respectively. The presence of these aggregates affects the accessibility of cellulose during its functionalization. A study of the evolution of the degree of substitution, DS, of cellulose acetate as a function of reaction time showed an increase up to 5 h, followed by a decrease at 7 h. Possible reasons for this decrease are discussed. As expected, M-sisal gave a higher DS that its untreated counterpart.

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In developing countries such as Brazil, the wastes generated in the decanters and filters of water treatment plants are discharged directly into the same rivers and streams that supply water for treatment. Another environmental problem is the unregulated discard of wood wastes. The lumber and wood products industry generates large quantities of this waste, from logging to the manufacture of the end product. Brazil has few biomass plants and therefore only a minor part of these wastes are reused. This paper presents the results of the first study involving a novel scientific and technological approach to evaluate the possibility of combining these two types of wastes in the production of a light-weight composite for concrete. The concrete produced with cement:sand:composite:water mass ratios of 1:2.5:0.67:0.6 displayed an axial compressive strength of 11.1 MPa, a compressive and diametral tensile strength of 1.2 MPa, water absorption of 8.8%, and a specific mass of 1.847 kg/m(3). The mechanical properties obtained with this concrete render it suitable for application in non-structural elements. (C) 2010 Elsevier Ltd. All rights reserved.

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Over the last decades, anti-resonant reflecting optical waveguides (ARROW) have been used in different integrated optics applications. In this type of waveguide, light confinement is partially achieved through an anti-resonant reflection. In this work, the simulation, fabrication and characterization of ARROW waveguides using dielectric films deposited by a plasma-enhanced chemical vapor deposition (PECVD) technique, at low temperatures(similar to 300 degrees C), are presented. Silicon oxynitride (SiO(x)N(y)) films were used as core and second cladding layers and amorphous hydrogenated silicon carbide(a-SiC:H) films as first cladding layer. Furthermore, numerical simulations were performed using homemade routines based on two computational methods: the transfer matrix method (TMM) for the determination of the optimum thickness of the Fabry-Perot layers; and the non-uniform finite difference method (NU-FDM) for 2D design and determination of the maximum width that yields single-mode operation. The utilization of a silicon carbide anti-resonant layer resulted in low optical attenuations, which is due to the high refractive index difference between the core and this layer. Finally, for comparison purposes, optical waveguides using titanium oxide (TiO(2)) as the first ARROW layer were also fabricated and characterized.

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Vitamin A (13-cis-retinol, all-trans-retinol and total carotenes) content was evaluated in 15 samples of enteral feeding formulas during 3-6,9 and 12 months of storage in closed containers, protected from light and at room temperature (22-30 degrees C). All formulas were nutritionally complete and/or recommended for different diseases. Equivalent batches were also evaluated after preparation and refrigerated storage for 24 h. Nutrient content did not decrease during both storage scenarios. Stability of vitamin A in the enteral feeding formulas, as determined in this study, is probably due to production and storage conditions, e.g. absence of oxygen in contact with the packaged product, the technological process used in the microencapsulation of vitamins, and protected storage in the absence of light and at a temperature maximum of 30 degrees C. (C) 2010 Elsevier Ltd. All rights reserved.

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We show that an arbitrary system described by two dipole moments exhibits coherent superpositions of internal states that can be completely decoupled fi om the dissipative interactions (responsible for decoherence) and an external driving laser field. These superpositions, known as dark or trapping states, can he completely stable or can coherently interact with the remaining states. We examine the master equation describing the dissipative evolution of the system and identify conditions for population trapping and also classify processes that can transfer the population to these undriven and nondecaying states. It is shown that coherent transfers are possible only if the two systems are nonidentical, that is the transitions have different frequencies and/or decay rates. in particular, we find that the trapping conditions can involve both coherent and dissipative interactions, and depending on the energy level structure of the system, the population can be trapped in a linear superposition of two or more bare states, a dressed state corresponding to an eigenstate of the system plus external fields or, in some cases. in one of the excited states of the system. A comprehensive analysis is presented of the different processes that are responsible for population trapping, and we illustrate these ideas with three examples of two coupled systems: single V- and Lambda-type three-level atoms and two nonidentical tao-level atoms, which are known to exhibit dark states. We show that the effect of population trapping does not necessarily require decoupling of the antisymmetric superposition from the dissipative interactions. We also find that the vacuum-induced coherent coupling between the systems could be easily observed in Lambda-type atoms. Our analysis of the population trapping in two nonidentical atoms shows that the atoms can be driven into a maximally entangled state which is completely decoupled from the dissipative interaction.

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We studied the results of chronic oral administration of amiodarone on in vitro lung tissue mechanics, light and electron microscopy. Fifteen Wistar male rats were divided into three groups. In control (CTRL) group animals received saline (0.5 mL/day). In amiodarone (AMIO) groups, amiodarone was administered by gavage at a dose of 175 mg/kg 5 days per week for 6 (6AMIO) or 12 weeks (12AMIO). Lung tissue strips were analyzed 24 h after the last drug administration. Tissue resistance and elastance were higher in 6AMIO and 12AMIO than in CTRL, while hysteresivity was similar in all groups. Total amount of collagen fibers in lung parenchyma increased progressively with the time course of the lesion. However, at 6 weeks there was an increase in the amount of type III collagen fibers, while in 12AMIO mainly type I collagen fibers were found. In our study amiodarone increased lung tissue impedance that was accompanied by matrix remodeling and lesion of type II pneumocytes. (C) 2008 Elsevier B.V. All rights reserved.

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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.