97 resultados para pae


Relevância:

10.00% 10.00%

Publicador:

Resumo:

This paper explores a decolonizing approach to research about Indigenous women’s health in Australia. The paper identifies the strengths of decolonizing methodologies as a way to prioritize Indigenous values and world views, develop partnerships between researchers and the researched, and contribute to positive change. The authors draw on Laenui’s (2000) five-step model of decolonization to describe their work in the Indigenous Women’s Wellness Project in Brisbane, Queensland, Australia. They argue that Laenui’s model presents a valuable framework for conducting decolonizing research projects about women’s health with Australian Indigenous women. The authors demonstrate that working within a decolonizing framework offers autonomy and sustainability for women’s wellness activities, while continuing to improve a community’s health and wellbeing outcomes.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This study investigated whether bystanders of traditional bullying and cyberbullying used face-to-face methods, online methods or both methods when reporting, discouraging and providing support to the victims of traditional bullying and cyberbullying. A questionnaire was completed by 348 high school students (Years 7 – 12) from seven independent schools in Australia. Overall, students predominantly utilized face-to-face methods when reporting to others for both types of bullying. Older students were more likely to use online methods to discourage the traditional bully (i.e., asking the bully to stop). Males and older students were more likely to use online methods to support victims of traditional bullying. Females were more likely to use face-to-face methods to support victims of cyberbullying. Implications for practice and future research are discussed.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An anthracene-containing poly(arylene-ethynylene)-alt-poly(arylene-vinylene) (PAE-PAV) of general constitutional unit (PhCCAnthrCCPhCHCHAnthrCHCH)(n) bearing two 2-ethylhexyloxy solubilizing side chains on each phenylene (Ph) unit has been synthesized and characterized. The basic electrochemical characterization was done, showing the existence of two non-reversible oxidation and one reversible reduction peaks. The optical properties, the real and imaginary part of the dielectric function, were probed using spectroscopic ellipsometry (SE). The vibrational structure of the undoped/doped polymer was investigated using Fourier transformed infrared spectroscopy. A strong change in the polaronic absorption was observed during the doping, which after modeling revealed the existence of two separated transitions. The optical changes upon doping were additionally recorded using the SE technique. Similar to the results from FT-IR spectroscopy, two new in-the-gap absorptions were found. Moreover, the electrical conductivity as well as the mobility of positive carriers were measured. In the undoped state, the conductivity of the polymer was found to be below the detection limit (

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A study of the pH and temperature dependence of the redox potentials of azurins from five species of bacteria has been performed. The variations in the potentials with pH have been interpreted in terms of electrostatic interactions between the copper site and titrating histidine residues, including the effects of substitutions in the amino acid sequences of the proteins on the electrostatic interactions. A comparison of the observed pH dependences with predictions based on histidine pK_a values known for Pseudomonas aeruginosa (Pae), Alcaligenes denitrificans (Ade), and Alcaligenes faecalis (Afa) azurins indicates that the Pae and Ade redox potentials exhibit pH dependences in line with electrostatic arguments, while Afa azurin exhibits more complex behavior. Redox enthalpies and entropies for four of the azurins at low and high pH values have also been obtained. Based on these results in conjuction with the variable pH experiments, it appears that Bordetella bronchiseptica azurin may undergo a more substantial conformational change with pH than has been observed for other species of azurin.

The temperature dependence of the redox potential of bovine erythrocyte superoxide dismutase (SOD) has been determined at pH 7.0, with potassium ferricyanide as the mediator. The following thermodynamic parameters have been obtained (T = 25°C): E°' = 403±5 mV vs. NHE, ΔG°' = -9.31 kcal/mol, ΔH°' = -21.4 kcal/mol, ΔS°' = -40.7 eu, ΔS°'_(rc) = -25.1 eu. It is apparent from these results that ΔH°', rather than ΔS°', is the dominant factor in establishing the high redox potential of SOD. The large negative enthalpy of reduction may also reflect the factors which give SOD its high specificity toward reduction and oxidation by superoxide.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Marc Ferrez (1843-1923), filho de franceses nascido no Brasil, exerceu por mais de cinqüenta anos a atividade de fotógrafo e comerciante de materiais afins. Para o presente estudo foi selecionada da imensa produção de Ferrez uma série de fotografias que pudesse abranger a diversidade de temas, regiões e períodos nos quais o fotógrafo atuou. A partir desta seleção foi estudada a contribuição da fotografia para a formação de uma identidade nacional brasileira, levando-se em conta os meios de circulação e recepção das fotografias e suas diversas formas de reprodução. Neste circuito visual travou-se um combate de imagens: de um lado o público que encomendava trabalhos de documentação fotográfica procurava apresentar uma nação n a marcha do progresso, de outro lado a comercialização de fotografias ou reproduções delas com grande aceitação em um mercado de imagens trazia especialmente temas como a natureza ou os tipos humanos exóticos. Na fotografia de Ferrez podemos apreender imagens de um país cujas elites sonhavam em mostrar civilizado, mas onde, a o mesmo tempo, predominava o elemento natural exuberante e os tipos exóticos. Elementos e temas essenciais para se discutir pertencimento, imaginário, identidade, enfim, para avaliar as construções da nação brasileira.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Tras la imposición de programas de ajuste estructural ordenados por los organismos internacionales ante la crisis de la deuda externa, y después de supeditar a estos planes sus políticas de desarrollo, los países latinoamericanos afrontan el presente siglo con aires nuevos y políticas económicas de diversa índole, las cuales pueden ser agrupadas principalmente en tres grandes bloques. Nos encontraremos así, en un primer grupo, con países como México, Chile, Colombia y Perú, que optaron por seguir la sugerida senda del neoliberalismo y firmar diversos tratados de libre comercio, apostando por economías abiertas y políticas de privatización. Un segundo bloque, compuesto por Brasil, Uruguay y Argentina, representa a aquellos países cuyas estrategias económicas han tratado de converger en una suerte de economías abiertas y políticas sociales. Finalmente, se analizarán en un tercer grupo los casos de Venezuela, Bolivia y Ecuador, principales países de la denominada Alianza Bolivariana (ALBA), los cuales comparten una fuerte ideología de izquierdas que aboga por una profunda acción social. Con el objetivo de exponer los diferentes retornos de estas tres principales estrategias, bucearemos a lo largo de las siguientes páginas en las características económicas, políticas y sociales inherentes a cada uno de estos países, tratando de dilucidar los aciertos y desaciertos de las nuevas políticas implementadas. Por último, se realizará una comparativa basada en datos macroeconómicos de todos los países objeto de estudio, con el fin de reflexionar sobre qué políticas económicas han logrado mejores resultados y a qué motivos se deben.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

No presente estudo foi avaliada (i) a estrutura das assembleias de peixes de igarapés de terra-firme ao longo do contínuo fluvial do rio Machado, na bacia do rio Amazonas, (ii) os efeitos de alterações ambientais sobre as assembleias de peixes de igarapés através de comparações entre áreas íntegras (em uma Unidade de conservação) e alteradas por ação antrópica na bacia hidrográfica do rio Machado, e (iii) a organização espacial das assembleias de peixes de tributários de baixa ordem na bacia do rio Machado através da avaliação dos padrões de co-ocorrência das espécies, identificando os possíveis fatores estruturadores dessas assembleias e através de uma Análise de Parcimônia de Endemismo (PAE). As amostragens foram realizadas entre os meses de agosto e setembro de 2011, junho e agosto de 2012 e julho de 2013, totalizando 81 igarapés. Os peixes foram coletados durante uma hora em um trecho de 80 metros, com o auxilio de uma rede de mão (picaré) e um puçá. Para o capítulo 1, um maior número de indivíduos e espécies foram encontradas no trecho baixo quando comparado o trecho alto da bacia. Todavia, somente foram encontradas diferenças significativas entre o trecho alto e os trechos médio e baixo. Assim, rejeitamos nossa hipótese de diferenças entre os trechos analisados, onde esperávamos que a riqueza e abundância de espécies de igarapés aumentaria no gradiente longitudinal cabeceira-foz do rio Machado. Contudo, apesar da não confirmação da hipótese, um padrão de adição e substituição de espécies foi observado do trecho alto para o médio, e um padrão de substituição de espécies foi observado do trecho médio para o baixo. Referente ao capítulo 2, apontamos que apesar da área desflorestada não apresentar diferenças marcantes na riqueza de espécies e abundância, quando comparada com a área com igarapés conservados, esta (área desflorestada) apresentou elevada similaridade a nível composicional entre os igarapés amostrados (menor diversidade beta), diferentemente dos igarapés localizados na Rebio, que apresentaram maior número de espécies com hábitos mais especializados. Igarapés desflorestados apresentaram homogeneização da sua ictiofauna em comparação com igarapés providos de mata ripária, refletindo a maior homogeneização estrutural encontrada em igarapés com baixo percentual de cobertura vegetal. Dessa forma, a retirada da cobertura vegetal em igarapés com comunidades mais diversificads e especializadas, como os da Rebio Jaru, promoveria a homogeneização das espécies acarretando a perda destas, assim como a substituição destas por espécies tolerantes a condições ambientais comuns a ambientes alterados. Para o capítulo 3, embora não tenhamos encontrado áreas de endemismo na bacia analisada, apontamos que a influência da estrutura física dos igarapés sobre a composição de espécies é o principal fator modulador da estruturação da assembleia de peixes. Todavia, tal fator não se aplica a estruturação da assembleia baseada na coocorrência de espécies, haja vista que, a análise de toda a bacia com diferentes níveis de uso de solo, apresentou um padrão organizacional não aleatório

Relevância:

10.00% 10.00%

Publicador:

Resumo:

通过台湾大陆初级淡水鱼类区系的比较分析,将台湾与大陆间的淡水鱼类区系和组成归纳为3种生物地理分布格局:(1)台湾与大陆东南沿海诸水系的淡水鱼类有很高相似性;(2)台湾与东喜马拉雅具有一些相同的淡水鱼类分布;(3)包括台湾岛在内的太平洋西部岛链的淡水鱼类区系之间的相似度很低,这些岛屿与各自相邻大陆的淡水鱼类更相似.从历史生物地理学的角度看,这种分布格局的形成与台湾和大陆古地理、地质的变迁有关.简约分析(PAE)结果认为,以上格局可以用隔离分化的假说加以解释,进一步的研究将使用分子生物地理学方法和手段对海峡两

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The bioaccumulation of phthalate acid esters (PAEs) from industrial products and their mutagenic action has been suggested to be a potential threat to human health. The effects of the most frequently identified PAE, Di-n-butyl phthalate (DBP), and its biodegradation, were examined by comparison of two small scale plots (SSP) of integrated vertical-flow constructed wetlands. The influent DBP concentration was 9.84 mg l(-1) in the treatment plot and the control plot received no DBP. Soil enzymatic activities of dehydrogenase, catalase, protease, phosphatase, urease, cellulase, beta-glucosidase, were measured in the two SSP after DBP application for 1 month and 2 months, and 1 month after the final application. Both treatment and control had significantly higher enzyme activity in the surface soil than in the subsurface soil (P < 0.001) and greater enzyme activity in the down-flow chamber than in the up-flow chamber (P < 0.05). In the constructed wetlands, DBP enhanced the activities of dehydrogenase, catalase, protease, phosphatase and inhibited the activities of urease, cellulase and beta-glucosidase. However, urease, cellulase, beta-glucosidase activities were restored 1 month following the final DBP addition. Degradation of DBP was greater in the surface soil and was reduced in sterile soil, indicating that this process may be mediated by aerobic microorgansims. DBP degradation fitted a first-order model, and the kinetic equation showed that the rate constant was 0.50 and 0.17 d(-1), the half-life was 1.39 and 4.02 d, and the r(2) was 0.99 and 0.98, in surface and subsurface soil, respectively. These results indicate that constructed wetlands are able to biodegrade organic PA-Es such as DBP. (c) 2005 Elsevier Ltd. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Through the comparative analysis of primary freshwater fishes in Chinese continent and the Taiwan Island, we summarize the three distinctions of distribution of freshwater fishes in these areas: (i) there exists a high similarity of freshwater fish fauna between Taiwan and the southeastern shore of the continent; (ii) some species of freshwater fish are found both in the Taiwan Island and East Himalayans; (iii) different freshwater fishes have different distributions in island arch of western Pacific where Taiwan is located, but the distribution pattern shows a similarity to that of adjacent continent. The characteristic distributions of the fishes are closely related to the change in paleogeography and geology in the area. The parsimony analysis of endemicity (PAE analysis) indicates that the three distribution patterns can be explained by the vicariance theory.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Optimized AlGaN/AlN/GaN high electron mobility transistors (HEMTs) structures were grown on 2-in semi-insulating (SI) 6H-SiC substrate by metal-organic chemical vapor deposition (MOCVD). The 2-in. HEMT wafer exhibited a low average sheet resistance of 305.3 Omega/sq with a uniformity of 3.85%. The fabricated large periphery device with a dimension of 0.35 pm x 2 nun demonstrated high performance, with a maximum DC current density of 1360 mA/mm, a transconductance of 460 mS/mm, a breakdown voltage larger than 80 V, a current gain cut-off frequency of 24 GHz and a maximum oscillation frequency of 34 GHz. Under the condition of continuous-wave (CW) at 9 GHz, the device achieved 18.1 W output power with a power density of 9.05 W/mm and power-added-efficiency (PAE) of 36.4%. While the corresponding results of pulse condition at 8 GHz are 22.4 W output power with 11.2 W/mm power density and 45.3% PAE. These are the state-of-the-art power performance ever reported for this physical dimension of GaN HEMTs based on SiC substrate at 8 GHz. (c) 2008 Elsevier Ltd. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Enhancement of the electrical properties in an AlGaN/GaN high electron mobility transistor (HEMT) structures was demonstrated by employing the combination of a high mobility GaN channel layer and an AlN interlayer. The structures were grown on 50 mm semi-insulating (SI) 6H-SiC substrates by metalorganic chemical vapor deposition (MOCVD). The room temperature (RT) two-dimensional electron gas (2DEG) mobility was as high as 2215 cm(2)/V s, with a 2DEG concentration of 1.044 x 10(13)cm(-2). The 50 mm HEMT wafer exhibited a low average sheet resistance of 251.0 Omega/square, with a resistance uniformity of 2.02%. The 0.35 Pin gate length HEMT devices based on this material structure, exhibited a maximum drain current density of 1300 mA/mm, a maximum extrinsic transconductance of 314 mS/mm, a current gain cut-off frequency of 28 GHz and a maximum oscillation frequency of 60 GHz. The maximum output power density of 4.10 W/mm was achieved at 8 GHz, with a power gain of 6.13 dB and a power added efficiency (PAE) of 33.6%. (c) 2006 Elsevier B.V. All rights reserved.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

AlGaN/GaN high electron mobility transistor (HEMT) structures were grown on 2 inch sapphire substrates by MOCVD, and 0.8-mu m gate length devices were fabricated and measured. It is shown by resistance mapping that the HEMT structures have an average sheet resistance of approximately 380 Omega/sq with a uniformity of more than 96%. The 1-mm gate width devices using the materials yielded a pulsed drain current of 784 mA/mm at V-gs=0.5 V and V-ds=7 V with an extrinsic transconductance of 200 mS/mm. A 20-GHz unity current gain cutoff frequency (f(T)) and a 28-GHz maximum oscillation frequency (f(max)) were obtained. The device with a 0.6-mm gate width yielded a total output power of 2.0 W/mm (power density of 3.33 W/mm) with 41% power added efficiency (PAE) at 4 GHz.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

以八甲基环四硅氧烷(D_4)为单体,α,ω-双(γ-氨丙基)四甲基二硅氧烷(DSX)为封端剂,在催化剂四甲基氢氧化铵硅醇盐的作用下,合成了五种不同分子量的α,ω-双(γ-氨丙基)聚二甲基硅氧烷预聚物(PSX)。预聚物分子量的测定结果表明,分子量的实验值接近理论值。以聚二甲基硅氧烷为软段,分别以聚芳酯(PAE)。聚酰亚胺(PI)为硬段合成了有机硅嵌段长短不同及含量不同的两类嵌段共聚物。1)PSX/PAE嵌段共聚分别采用界缩聚法和低温溶液法使酚酞、对苯二甲酰氯同端氨丙基聚硅氧烷预聚物合成了聚二甲基硅氧烷-聚对苯二甲酸酚酞酯嵌段共聚物。使用NMR对共聚物的组成分析以及测定共聚物粘度的结果表明,采用界面法不易得到有机硅含量较高、高产率、高分子量的共聚物,而低温溶液法却能给出高分子量、高产率及有机硅含量可控的嵌段共聚物。以IR、NMR对共聚物的结构、组成进行了表征,还以TEM观察了有机硅嵌段长短、含量的多少以及成膜溶剂对共聚物形态的影响。当共聚物中有机硅含量一定时,相分离程度随有机硅嵌段长度的减小而变小。在软硬段的组成比较大地偏离50/50时,共聚物中较多的组份形成连续相,且由于软硬段的溶解度参数相差较大,相容性不好而使共聚物在有机硅嵌段较短((M-bar)_n = 915)的情况下发生相分离。TMA、DSC及动态力学试验表明,共聚物分别表现出软硬段的转变,且当软段的聚合度大于40时,出现聚二甲基硅氧烷的结晶和熔融转变。某些共聚物的力学强度接近或大于硬段聚芳酯,而断裂伸长率均大于聚芳酯。TGA分析指出,共聚物具有比较好的耐热性。对共聚物透气性的初步测试表明,嵌段共聚物的透气性主要表现出连续相聚合物的性质。2)PSX/PI嵌段共聚物由嵌段共聚物的IR谱表明环化反应完全,由NMR谱确定共聚物中有机硅的含量。由于PI与PSX的相容性很不好(Δδ = 11.7)。TEM观察结果表明共聚物在有机硅嵌段较短((M-bar)_n = 915)时即发生相分离,且相分离的程度比聚芳酯要大。共聚物的DSC测试结果也证明了共聚物的两相结构,共聚物具有比较好的耐热性。此外,对有机硅嵌段较短的共聚物的透气性测试表明,共聚物在具有较好的透气性(P_(O_2)为10~(-9)cm~3(STP)cm/cm~2·sec·cmHg数量级)的同时,还呈现出比较好的氧氮分离能力(α_(H_2)~(O_2) > 2.5)。

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A power amplifier MIC with power combining based on AlGaN/GaN HEMTs was fabricated and measured. The amplifier consists of four 10×120μm transistors. A Wilkinson splitters and combining were used to divide and combine the power. By biasing the amplifier at V_(DS) =40V, I(DS)= 0. 9A, a maximum CW output power of 41. 4dBm with a maximum power added efficiency (PAE) of 32. 54% and a power combine efficiency of 69% was achieved at 5. 4GHz.