Preparação e caracterização de microesferas poliméricas com morfologia casca-núcleo e propriedades magnéticas à base de estireno e divinilbenzeno

Foram sintetizadas microesferas poliméricas com propriedades magnéticas e morfologia casca-núcleo por meio da técnica de polimerização em suspensão em duas etapas. O núcleo foi constituído por poli(estireno-co-divinilbenzeno) e magnetita modificada com ácido oleico. Foi avaliada a influência da velocidade de agitação e da concentração de iniciador sobre as características das microesferas utilizadas como núcleo (morfologia, tamanho de partículas, propriedades magnéticas e estabilidade térmica). A casca foi constituída por poli(estireno-co-divinilbenzeno) sem material magnético. Foi avaliado o método de adição da emulsão dos monômeros formadores da casca e o tempo de inchamento dos núcleos na emulsão. As microesferas casca-núcleo foram caracterizadas quanto ao seu aspecto morfológico e à estabilidade térmica. Os núcleos não apresentaram ciclos de histerese, estando assim próximos de um material com propriedades superparamagnéticas. O copolímero sintetizado com a maior velocidade de agitação e a menor concentração de iniciador foi o que apresentou o maior teor de ferro incorporado (3,317 %), a maior magnetização de saturação (2,99 emu/g) e o menor diâmetro médio de partículas (81 m). As microesferas casca-núcleo apresentaram apenas um estágio de degradação e as suas Tmáx foram menores do que a do núcleo. O mapa composicional de ferro confirmou a presença de magnetita na superfície das microesferas casca-núcleo

人－组织匹配等因素对员工的满意度、组织承诺的影响

P-J Fit and P-O Fit are focus problems in the investigation field of industry and organization psychology. They have distinct influences on staff job performance and job attitude. In a certain extend,these influences are moderated by some variables. LMX(Leader-member Exchange) and TMX(Team-member exchange) are two most important personal relationship types in job scene. Post investigations indicated that they are equal to forecasting variables and moderating variables of staff job performance and job attitude. From actualities, although there are many investigations about the relationships between P-J Fit, P-O Fit, LMX, TMX and job attitude, these investigations only focused on some aspects, and they discussed little about four aspects at one time and mutual influences. Using hierarchical regression analysis to analyze the survey data collected from 592 employees in a big governmental telecom company, we got some results as follows: (1)After controlling demography variables, standardized regression coefficients on P-J Fit, P-O Fit, LMX, TMX and job satisfaction, organization commitment are all positive, and reach distinct levels. (2) LMX could distinctly moderate the influences of P-J Fit, P-O Fit on job satisfaction, but couldn’t distinctly moderate the influences of the two on organization commitment. Specifically, as LMX increased,the effect of P-J on job satisfaction decreased gradually,while the effect of P-O increased. (3) TMX could not distinctly moderate the relationships between P-J Fit, P-O Fit, job satisfaction and organization commitment. The theoretical implication of this investigation lies in enriching and developing investigations in these fields in a certain extend, through conforming the influences of P-J Fit, P-O Fit, LMX, and TMX on job satisfaction and organization commitment. The practical implication lies in revealing these aspects for corporation governors: When selecting applications for a job, they should try their best to realize the best fit of personal ability and the job requirements, personal value and organization culture. They should enhance staff job satisfaction and organization commitment through furthering the relationship between the leader and members, team members each other. They should cushion disadvantage influences of non-P-J Fit on staff job satisfaction and enhance positive influences of P-O Fit. 【Key words】 person-job fit; person-organization fit; leader-member exchange; team member exchange; job attitude

Bases del control del comportamiento anual o bienal en el cultivo oleaginoso Oenothera biennis

El comportamiento bienal facultativo de Oenothera biennis representa una limitante para su explotación comercial extensiva. Los individuos de esta especie pueden florecer en la primera estación de crecimiento (ciclo anual) o retrasar su floración hasta la siguiente (ciclo bianual). Este comportamiento estaría modulado por la capacidad endógena de las plantas para responder a las señales ambientales que desencadenan la floración, la cual dependería del logro de un umbral de biomasa. El objetivo de esta tesis fue contribuir al entendimiento de los factores que controlan la floración de Oenothera biennis haciendo énfasis en la relación entre el tamaño de las plantas y su respuesta a las señales inductoras de la reproducción. Se realizaron experimentos en macetas a campo donde se manipularon factores candidatos a inducir la floración (vernalización y fotoperíodo). Se modificó la disponibilidad de nutrientes mediante fertilización mineral, para lograr variabilidad en los indicadores de la condición endógena de las plantas (área y tasa de crecimiento de las rosetas). La vernalización, el fotoperíodo (días largos) y la fertilización redujeron la incidencia de plantas de comportamiento bienal (hasta 25 por ciento respecto al control) y adelantaron la floración entre 3 y 31 días (según tratamiento y condiciones experimentales) en las plantas de comportamiento anual La respuesta a la vernalización fue facultativa y no dependió de una biomasa umbral, ya que se vernalizaron plántulas recién germinadas. La respuesta al fotoperíodo tampoco requirió de un tamaño umbral, pero estuvo condicionada por la tasa de crecimiento de las plantas, la cual fue modulada por la fertilización y el área de las rosetas al inicio de las condiciones fotoinductivas. Se identificó a la incidencia de temperaturas elevadas (T media menor a 25ºC; Tmáx menor a 30ºC), alrededor de la iniciación floral, como un posible factor causal de la bianualidad que inhibiría la reproducción, de una proporción de los individuos, en fechas de siembra tardías. Se concluye que los factores que aceleran el desarrollo (vernalización, fotoperíodos extendidos artificialmente y nutrición mineral) contribuyen indirectamente a reducir la bianualidad, evitando que las condiciones inductivas de la floración coincidan con el período estival de alta temperatura.

The role of sexual steroids in the modulation of growth hormone (GH) secretion in humans

Sex steroids contribute to modulate GH secretion in man. However, both the exact locus and mechanism by which their actions are exerted still remain not clearly understood. We undertook a number of studies designed to ascertain: (1) whether or not sudden or chronic changes in circulating gonadal steroids may affect GH secretion in normal adults; and (2) the reason(s) for gender-related dimorphic pattern of GH release. The pituitary reserve of GH, as evaluated by means of a GHRH challenge, was similar in women with anorexia nervosa and in normally menstruating women. Estrogenic receptor blockade with tamoxifen (TMX) did not significantly change GHRH-induced GH response in these normal women. Therefore, acute or chronic hypoestrogenism apparently had no important effects at level of somatotrophs. In another group of normal women we tested the possibility that changes in circulating estrogens might induce changes in the hypothalamic-somatotroph rhythm (HSR). GHRH challenges were performed throughout a menstrual cycle, and again after having achieved functional ovarian blockade with a GnRH agonist treatment. Short-term ovarian blockade did not significantly affect the parameters of GH response to GHRH, although it was accompanied by an increase in the number of women ina refractory HSR phase at testing. This suggested a low potentiating effect on the basic pattern of somatostatin (SS) release occurring as a consequence of the decrease in circulating estrogens. In normal men, neither the GH response to GHRH nor the HSR were affected by functional testicular blockade (after GnRH agonist treatment). However, the administration of testosterone enanthate (250 mg) to another group of men increased both the GHRH-induced GH release and the number of subjects in a spontaneous secretory HSR phase at testing; these were reversed by estrogenic receptor blockade with TMS. In another group of normal men, the fraction of GH secreted in pulses (FGHP) during a nocturnal sampling period was significantly decreased by testicular blockade. Other parameters of GH secretion, such as the number of GH pulses and their mean amplitude (A), and the mean plasma GH concentration (MCGH), showed a slight, although not significant, decrease following the lack of androgens. The administration of testosterone enanthate (500 mg) reversed these parameters to values similar to those in the basal study. Interestingly, when tamoxifen was given after testosterone enanthate, A, MCGH and FGHP increased to values significantly higher than in any other experimental condition in that study. In all, these data suggest that 17ß-estradiol may participate in GH modulation by inhibiting the hypothalamic release of somatostatin, while testosterone stimulates it. The results obtained after estrogenic receptor blockade appear to indicate that the effect of testosterone in such a modulation is dependent on its aromatization to 17ß-estradiol. The differential levels of this steroid in both sexes might account for the sexual dimorphic pattern of GH secretion. From other data in the literature, obtained in rats, and our preliminary data in children with constitutional delay of growth and puberty, it is tempting to speculate that the effect of 17ß-estradiol may be exerted by modifying the functional activity of a-2 adrenergic pathways involved in the negative modulation of SS release.

Dinâmica populacional do caranguejo-uçá, Ucides cordatus (Linnaeus, 1763) (CRUSTACEA, BRACHYURA, UCIDIDAE) no município de Porto do Mangue, litoral norte do estado do Rio Grande do Norte

Decapod crustaceans are one of the most important portions of megafaunal of coastal waters, playing a role as modifier of the environment and controlling populations of other organisms. Among the Decapoda, crab (brachyuran) constitutes the dominant macrofauna of mangroves. Among brachyuran is the mangrove crab (Ucides cordatus, Linnaeus, 1763), which represents the main component of the macrofauna of mangroves, particularly in Northern and Northeastern Brazil. In Brazil, its distribution is known from the state of Amapá to the north of Santa Catarina. This species is distinguished by its economic importance, being one of the main fishing resources in Brazil, generating a significant impact on their natural populations. This reduction would result in loss of value to the product, preventing its commercialization. Although it´s great ecological and economic importance, there are few articles about the biological aspects of U. cordatus, mainly in the state of Rio Grande do Norte. This work aimed to study the population dynamics of the mangrove crab, Ucides cordatus (Linnaeus, 1763), in Conchas estuary, Porto do Mangue, northern coast of Rio Grande do Norte. During the period November 2009 to October 2010 the crabs were collected monthly, obeying predetermined lunar periods (new moon or full moon) in a mangrove area in Porto do Mangue - RN. With the aid of a steel caliper (0.01 mm) and a precision balance (0.01 g) were measured biometric variables related to the animal's carapace, major propodus chela, width of abdomen (female), length of gonopodium ( males) and total weight. In addition, it was recorded, the gonads and molt stages, for males and females. In total, 476 crabs were collected, with 338 males and 138 females. Males were larger, heavier and in greater proportion than females. The reproductive period for the species in this location was limited during the months November to May, suggesting a change in current environmental legislation for the closure period. Synchrony was observed between the morphological and physiological maturity with females maturing earlier, possibly, a reproductive strategy adopted, compared to the low fishing pressure in the area. The molting period occurred in the dry season peaking in October. The analysis of growth, based on the parameters of von Bertalanffy was calculated using the nonlinear fit using modes (AJMOD). High growth rates for both males (L = 7.54 cm, k = 0.95, t0 =- 00:08; tmax = 4.84) and females (L = 6.50, k = 1 , 2, t0 =- 0008; tmax = 3.28) were found, contrasting with data from the literature, using other techniques. Males had higher asymptotic width size and longevity, but a lower growth constant when compared with females. The estimated age, for males and females, reaching the minimum capture size was 1.82 years and 1.63 years respectively. The size of physiological maturity, when individuals are able to reproduce, was estimated at 1.4 years and 1.05 years, for males and females, respectively. The recruitment period for this species is seasonal, with two peaks of occurrence, one in the rainy season and one in the dry season. This work represented the first effort on understanding the ecology of the mangrove crab, to the northern coast of Rio Grande do Norte. However, further studies on its biology should be undertaken, especially those related to growth, and recruitment, where observed that literature is more scarce

Análise das tensões geradas durante a contração de polimerização e aplicação de cargas em restaurações diretas de resina composta. Efeito da utilização de materiais para base ou forramento

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Farmacocinética pré-clínica e avaliação toxicológica preliminar da nova tiazolidinadiona desenvolvida para o tratamento do diabetes mellitus tipo 2: 5-(4-cloro-benzilideno)-3-(4-metil-benzil)-tiazolidina-2,4-diona (GQ-2)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Farmacocinética do Benznidazol administrado em coelhos na forma de comprimidos de liberação imediata e comprimidos de liberação prolongada

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Bitext alignment: building and evaluating a bilingual corpus and translation memory of academic course descriptions

Following the internationalization of contemporary higher education, academic institutions based in non-English speaking countries are increasingly urged to produce contents in English to address international prospective students and personnel, as well as to increase their attractiveness. The demand for English translations in the institutional academic domain is consequently increasing at a rate exceeding the capacity of the translation profession. Resources for assisting non-native authors and translators in the production of appropriate texts in L2 are therefore required in order to help academic institutions and professionals streamline their translation workload. Some of these resources include: (i) parallel corpora to train machine translation systems and multilingual authoring tools; and (ii) translation memories for computer-aided tools. The purpose of this study is to create and evaluate reference resources like the ones mentioned in (i) and (ii) through the automatic sentence alignment of a large set of Italian and English as a Lingua Franca (ELF) institutional academic texts given as equivalent but not necessarily parallel (i.e. translated). In this framework, a set of aligning algorithms and alignment tools is examined in order to identify the most profitable one(s) in terms of accuracy and time- and cost-effectiveness. In order to determine the text pairs to align, a sample is selected according to document length similarity (characters) and subsequently evaluated in terms of extent of noisiness/parallelism, alignment accuracy and content leverageability. The results of these analyses serve as the basis for the creation of an aligned bilingual corpus of academic course descriptions, which is eventually used to create a translation memory in TMX format.

Calibración del modelo de Hargreaves para la estimación de la evapotranspiración de referencia en Coronel Dorrego, Argentina

La Organización de las Naciones Unidas para la Agricultura y la Alimentación FAO propone el uso de la ecuación de Penman-Monteith (PM) como el estándar para la estimación de la evapotranspiración de referencia y para la calibración de otras ecuaciones. El principal inconveniente del uso de esta ecuación es que requiere datos que no se tienen en la mayoría de las estaciones. El uso de métodos de cálculos alternativos es usual en la bibliografía. El método de Hargreaves (HG), recomendado por la FAO, es el más usado en la bibliografía cuando sólo se dispone de los datos de temperaturas. El principal objetivo de este trabajo es analizar la posibilidad de calibración y ajuste del método HG en la estación de Coronel Dorrego. Se han comparado los métodos PM y HG, encontrándose una buena correlación entre ambos. Se concluye que el modelo HG es una metodología adecuada, para la zona de Coronel Dorrego y se sugiere la fórmula siguiente: ETo HG = 0,00206⋅Ra⋅(Tmáx-- T mín) 0,49⋅(tm+17,8) mm/día

Control rod drop surveillance using two friction coefficients

In the case of large burnup, a control rod (CR) guide tube in the pressurized water reactor of a commercial nuclear power plant might bend. As a consequence, a CR drop experiment may indicate an event of a CR partially inserted and whether the CR should be deemed inoperable. Early prevention of such an event can be achieved by measuring two friction coefficients: the hydraulic coefficient and the sliding coefficient. The hydraulic coefficient hardly changes, so that the curvature of the guide tube can only be detected thanks to a variation of the sliding coefficient. A simple model for the CR drop is established and validated with CR drop experiments. If tmx denotes the instant of CR maximum velocity, a linear relationship between (tmx)_2 and the sliding coefficient is found.

Impacto do pH final na maciez do músculo Longissimus lumborum de animais zebuínos: mudanças estruturais de proteínas da carne crua e cozida durante a maturação

O objetivo do presente trabalho foi determinar a força de cisalhamento Warner-Bratzler do músculo Longissimus lumborum de animais zebuínos machos inteiros (Bos indicus) durante o período de maturação, nas faixas de pH final (pHf 48 horas post mortem) normal (pH entre 5,5 e 5,8) e anormal (pH entre 5,81 e 6,19) e temperaturas internas de cozimento. Concomitante com a avaliação de força de cisalhamento, foram avaliadas também a degradação da desmina e troponina T, o comprimento do sarcômero, o teor de colágeno total e solúvel, as temperaturas máximas de desnaturação das proteínas e a morfologia geral de agregação das fibras do músculo no cozimento. A degradação da desmina e troponina T foi maior no pHf normal, aparecendo produtos de degradação a partir do dia 7 nessa faixa de pHf. Não houve diferenças nos valores de comprimento do sarcômero, descartando-se assim, a contribuição desse parâmetro sobre a temperatura máxima de desnaturação (Tmáx) das proteínas, determinada utilizando calorímetro exploratório diferencial (DSC). Similarmente, não foram encontradas diferenças para os teores de colágeno total e solúvel, e os valores de colágeno total foram baixos, sugerindo que sua contribuição na segunda transição térmica e nos valores de força de cisalhamento foi mínima. As Tmáx1 e Tmáx2, correspondentes à desnaturação da meromiosina leve e pesada, respectivamente, foram menores no pHf normal, mas o efeito foi maior para a Tmáx2. A Tmáx3 da actina e titina aumentou até 14 dias post mortem na faixa de pHf normal, e posteriormente diminuiu significativamente após 21 dias, sugerindo possível degradação dessas proteínas nesse período de dias. Não foram encontradas diferenças nos valores de Tmáx no pHf anormal, em todos os dias post mortem, o que sugere a contribuição de um possível mecanismo de proteção que estabiliza as miofibrilas no aquecimento. Houve maior agregação das fibras do músculo no pHf normal nas temperaturas internas de cozimento de 65 e 80°C, provavelmente devido à maior desnaturação térmica das miofibrilas. Os valores de força de cisalhamento foram maiores com o aumento da temperatura interna de cozimento, devido ao aumento da desnaturação térmica das miofibrilas do músculo. Independente da temperatura interna de cozimento, os valores de força de cisalhamento foram altos em quase todos os dias post mortem para ambas as faixas de pHf, o que sugere a necessidade de utilizar métodos físicos ou químicos para aumentar a maciez do músculo Longissimus lumborum de animais zebuínos.

A multilevel analysis of team climate and interpersonal exchange relationships at work

This study advances research on interpersonal exchange relationships by integrating social exchange, workplace friendship and climate research to develop a multilevel model. Data were collected from 215 manager-employee dyads working within 36 teams. At the individual level, LMX was positively associated with TMX and workplace friendship. Further, workplace friendship was positively related to TMX, and mediated the LMX-TMX relationship. At the team level, HLM results demonstrated that the relationship between LMX and workplace friendship was moderated by affective climate. Findings suggest that high-quality LMX relationships are associated with enhanced employees' perceptions of workplace friendship when affective group climate was strong.