Comparative study of the radiation-induced grafting of styrene onto poly(tetrafluoroethylene-co-perfluoropropylvinyl ether) and polypropylene substrates. I: Kinetics and structural investigation

A comparative study has been made of the radiation grafting of styrene onto poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether) (PFA) and polypropylene (PP) substrates, using the simultaneous irradiation method. Effects of grafting conditions such as monomer concentrations, type of solvent, dose rate and irradiation dose on the grafting yield were investigated. Under the same grafting conditions it was found that a higher degree of grafting of styrene was obtained using a mixture of dichloromethane/methanol solvents for PFA and methanol for PP and the degree of grafting was higher in PP than in PFA at all doses. However, the micro-Raman spectroscopy analysis of the graft revealed that, for the same degree of grafting, the penetration depth of the grafted polystyrene into the substrate was higher in PFA than in PP substrates. In both polymers the crystallinity was hardly affected by the grafting process and the degree of crystallinity decreased slightly with grafting dose. The dependence of the initial rate of grafting on the dose rate and the monomer concentration was found to be 0.6 and 1.4 order for PFA and 0.15 and 2.2 for PP, respectively. The degree of grafting increased with increasing radiation dose in both polymers. However, the grafting yield decreased with an increase in the dose rate. The increase in the overall grafting yield for PFA and PP was accompanied by a proportional increase in the penetration depth of the graft into the substrates. (C) 2003 Society of Chemical Industry.

A protective effect of early pregnancy factor on experimental autoimmune encephalomyelitis induced in Lewis rats by inoculation with myelin basic protein

Experimental antoimmune encephalomyelitis (EAE) is an organ-specific autoimmune disease characterised by inflammation and demyelination of the central nervous system and is the best available animal model of multiple sclerosis (MS). Since previous studies have shown that EAE is less severe or is delayed in onset during pregnancy and that administration of the pregnancy hormone early pregnancy factor (EPF) down-regulates EAE, experiments in the present study were designed to explore further the role of EPF in EAE. By using the rosette inhibition test, the standard bioassay for EPF and, by semi-quantitative RT-PCR techniques, we have now shown that inflammatory cells from the spinal cord of rats with EAE can produce and secrete EPF, with production being greatest during recovery from disease. Administration of EPF to rats with EAE resulted in a significant increase in the expression of IL-4 and IL-10 mRNA and a significant decrease in IFN-gamma mRNA expression in spinal cord inflammatory cells. Encephalitogenic MBP-specific T cell lines were prepared from popliteal lymph nodes of rats with EAE. Proliferation assays using these cells demonstrated the ability of exogenous EPF to down-regulate the responses of T lymphocytes to MBP. (C) 2003 Elsevier B.V. All rights reserved.

The application of wave induced forces to a two-dimensional finite element long wave hydrodynamic model

This paper describes the modification of a two-dimensional finite element long wave hydrodynamic model in order to predict the net current and water levels attributable to the influences of waves. Tests examine the effects of the application of wave induced forces, including comparisons to a physical experiment. An example of a real river system is presented with comparisons to measured data, which demonstrate the importance of simulating the combined effects of tides and waves upon hydrodynamic behavior. (C) 2002 Elsevier Science Ltd. All rights reserved.

Low temperature induced spikelet sterility in rice. I. Nitrogen fertilisation and sensitive reproductive period

Low temperature during panicle development in rice increases spikelet sterility. This effect is exacerbated by high rates of nitrogen (N) application in the field. Spikelet sterility induced by low temperature and N fertilisation was examined in glasshouse experiments to clarify the mechanisms involved. In two glasshouse experiments, 12-h periods of low (18/13degreesC) and high (28/23degreesC) day/night temperatures were imposed over periods of 5-7 days during panicle development, to determine the effects of low temperature and N fertilisation on spikelet sterility. In one experiment, 50% sunlight was imposed together with low temperature to investigate the additive effects of reduced solar radiation and low temperature. The effect of increased tillering due to N fertilisation was examined by a tiller removal treatment in the same experiment. Pollen grain number and spikelet sterility were recorded at heading and harvest, respectively. Although there was no significant effect of low temperature on spikelet sterility in the absence of applied N, low temperature greatly increased spikelet sterility as a result of a reduction in the number of engorged pollen grains per anther in the presence of applied N. Spikelet sterility was strongly correlated with the number of engorged pollen grains per anther. Low temperature during very early ( late stage of spikelet differentiation-pollen mother cell stage) and peak ( second meiotic division stage-early stage of extine formation) microspore development caused a severe reduction in engorged pollen production mainly as a result of reduced total pollen production. Unlike low temperature, the effect of shading was rather small. The increased tillering due to application of high rates of N, increased both spikelet number per plant and spikelet sterility under low temperature conditions. The removal of tillers as they appeared reduced the number of total spikelets per plant and maintained a large number of engorged pollen grains per anther which, in turn, reduced spikelet sterility. The number of engorged pollen grains per anther determined the numbers of intercepted and germinated pollen grains on the stigma. It is concluded that N increased tillering and spikelet number per plant and this, in turn, reduced the number of engorged pollen grains per anther, leading into increased spikelet sterility under low temperature condition.

Low temperature induced spikelet sterility in rice. II. Effects of panicle and root temperatures

Low temperatures impose restrictions on rice (Oryza sativa L.) production at high latitudes. This study is related to low temperature damage that can arise mid-season during the panicle development phase. The objective of this study was to determine whether low temperature experienced by the root, panicle, or foliage is responsible for increased spikelet sterility. In temperature-controlled glasshouse experiments, water depth, and water and air temperatures, were changed independently to investigate the effects of low temperature in the root, panicle, and foliage during microspore development on spikelet sterility. The total number of pollen and number of engorged pollen grains per anther, and the number of intercepted and germinated pollen grains per stigma, were measured. Spikelet sterility was then analysed in relation to the total number of pollen grains per spikelet and the efficiency with which these pollen grains became engorged, were intercepted by the stigma, germinated, and were involved in fertilisation. There was a significant combined effect of average minimum panicle and root temperatures on spikelet sterility that accounted for 86% of the variation in spikelet sterility. Total number of pollen grains per anther was reduced by low panicle temperature, but not by low root temperature. Whereas engorgement efficiency ( the percentage of pollen grains that were engorged) was determined by both root and panicle temperature, germination efficiency (the percentage of germinated pollen grains relative to the number of engorged pollen grains intercepted by the stigma) was determined only by root temperature. Interception efficiency (i.e. percentage of engorged pollen grains intercepted by the stigma), however, was not affected by either root or panicle temperature. Engorgement efficiency was the dominant factor explaining the variation in spikelet sterility. It is concluded that both panicle and root temperature affect spikelet sterility in rice when the plant encounters low temperatures during the microspore development stage.

Acute lead-induced vasoconstriction in the vascular beds of isolated perfused rat tails is endothelium-dependent

Chronic lead exposure induces hypertension in humans and animals, affecting endothelial function. However, studies concerning acute cardiovascular effects are lacking. We investigated the effects of acute administration of a high concentration of lead acetate (100 µΜ) on the pressor response to phenylephrine (PHE) in the tail vascular bed of male Wistar rats. Animals were anesthetized with sodium pentobarbital and heparinized. The tail artery was dissected and cannulated for drug infusion and mean perfusion pressure measurements. Endothelium and vascular smooth muscle relaxation were tested with acetylcholine (5 µg/100 µL) and sodium nitroprusside (0.1 µg/100 µL), respectively, in arteries precontracted with 0.1 µM PHE. Concentration-response curves to PHE (0.001-300 µg/100 µL) were constructed before and after perfusion for 1 h with 100 µΜ lead acetate. In the presence of endothelium (E+), lead acetate increased maximal response (Emax) (control: 364.4 ± 36, Pb2+: 480.0 ± 27 mmHg; P < 0.05) and the sensitivity (pD2; control: 1.98 ± 0.07, 2.38 ± 0.14 log mM) to PHE. In the absence of endothelium (E-) lead had no effect but increased baseline perfusion pressure (E+: 79.5 ± 2.4, E-: 118 ± 2.2 mmHg; P < 0.05). To investigate the underlying mechanisms, this protocol was repeated after treatment with 100 µM L-NAME, 10 µM indomethacin and 1 µM tempol in the presence of lead. Lead actions on Emax and pD2 were abolished in the presence of indomethacin, and partially abolished with L-NAME and tempol. Results suggest that acute lead administration affects the endothelium, releasing cyclooxygenase-derived vasoconstrictors and involving reactive oxygen species.

Da partilha à acção colectiva dos cidadãos: O contributo dos Novos Media no apelo à dádiva de medula óssea

O contributo das redes sociais na luta contra o cancro tem sido conhecida, especialmente, pelo sucesso de movimentos de cidadãos com o objectivo de sensibilizar a sociedade portuguesa para a dádiva de medula óssea. Este tipo de campanhas solidárias, com o apoio dos Novos Media, foi um fenómeno iniciado em 2009 e tem vindo a desenvolver-se, sobretudo, no Facebook. Desde então, novos movimentos têm aparecido regularmente nesta rede social e ajudado a um aumento significativo do registo de dadores. Interessa-nos perceber como se desenvolvem este tipo de campanhas e que factores, contribuíram para o seu sucesso, procurando averiguar não só o poder da Web 2.0, mas também questões sobre a comunicação, a imagem e os media. O sucesso destes movimentos vai muito além da simples presença no Facebook. A análise global do sistema de comunicação é fundamental para compreender o diferente nível de sucesso atingido por cada movimento. No presente artigo, fazemos uma análise comparativa entre os principais movimentos de cidadãos, ocorridos entre 2009 e 2011, que comprova as supracitadas hipóteses.

Os Media Participativos e o poder da Identidade na Oncologia: o Cidadão e a Instituição enquanto Marcas interactivas

Neste artigo procuramos averiguar a relevância que as marcas e identidades têm nas plataformas participativas no contexto da saúde, em particular na oncologia. Apesar de estas plataformas disponibilizarem aos cidadãos e instituições as mesmas ferramentas, a sua capacidade de mobilização não é a mesma. As instituições parecem ter maior facilidade, mas nem sempre tal acontece. Discutir o conceito de marca e de identidade contribuirá para responder a esta questão, bem como compreender porque é que as diferenças entre os cidadãos e as instituições se podem atenuar nos novos media. Baseamos a nossa análise na observação de páginas do Facebook, de instituições oncológicas e de grupos de apoio de cidadãos; num conjunto de entrevistas a doentes e familiares oncológicos; e em diferentes estudos na saúde. No fim, procura-se esclarecer a importância do estudo das marcas e da identidade, como possível directriz de novas soluções nos media participativos, que contribuam para atenuar o problema individual do cidadão que se relaciona com o cancro.

Gender wage and productivity differentials in the Portuguese tourism industry

The objective of this paper is to provide empirical evidence on the determinants of gender wage inequality in the Portuguese tourism industry. Relying on firm level wage equations and production functions, gender wage and productivity differentials are estimated and then compared in order to infer whether observed gender disparities are justifiable on the grounds that women are relatively less productive than men, or instead disparities are due to gender wage discrimination. This approach is applied to tourism industry data gathered in the matched employer-employee data set Quadros de Pessoal (Employee Records). The main findings indicate that female employees in the tourism industry in Portugal are less productive than their male colleagues and that gender differences in wages are fully explained by gender differences in productivity.

Gender, wages, and productivity: an analysis of the tourism industry in northern Portugal

Tourism represents a major economic activity in Portugal, with an enormous wealth and employment growth potential. A significant proportion of jobs in the industry tourism are occupied by women, given that this industry is characterized by a relatively higher percentage of female employees. Despite the evidence of female progress with regard to their role in the Portuguese labor market, women continue to earn less than their male counterparts. This is clearly the case of the tourism industry, where statistics reveal a persistent gender wage gap. The objective of this paper is to provide empirical evidence on the determinants of gender wage inequality in the tourism industry in northern Portugal. Relying on firm-level wage equations and production functions, gender wage and productivity differentials are estimated and then compared. The comparison of these differentials allows inferring whether observed wage disparities are attributable to relatively lower female productivity, or instead disparities are due to gender wage discrimination. This approach is applied to tourism industry data gathered in the matched employer-employee data set Quadros de Pessoal (Employee Records). The main findings indicate that female employees in the tourism industry in northern Portugal are less productive than their male colleagues and that gender differences in wages are fully explained by gender differences in productivity.

Residents’ perceptions of tourism impacts in Guimarães (Portugal): a cluster analysis

In this investigation, a cluster analysis was used to separate Guimara˜es (Portugal) residents into clusters according to their perceptions of the impacts of tourism development. This approach is uncommonly applied to Portugal data and is even rarer for world heritage sites. The world heritage designation is believed to make an area more attractive to tourists. The clustering procedure analysed 400 data observations from a Guimara˜es resident survey and revealed the existence of three clusters: the Sceptics, the Moderately Optimistic and the Enthusiasts. The results were consistent with the empirical literature’s results, with the emergent nature of the destination found to be relevant. The fact that tourism is relatively recent in this destination has its major reflex in the devaluation by most of the residents of the negative impacts of tourism development.

Evaluating the Guimarães 2012 European Capital of Culture (ECOC): a Tourist Perception Approach

Guimarães has hosted, during the year of 2012, one of the European Capital of Culture (ECOC). The evaluation of the event is needed as public, private and community funds are involved. The approach considers the tourists (domestic and international) as external and independent stakeholders who assessed the cultural activities developed during the event and the attributes of the city. The results of the survey show that hosting the 2012 ECOC was a major contribution for attracting new visitors to the city, although many of them just for a short period of time. The main source of general information collected by tourists was the Internet, and the traditional media. Only a small amount of respondents demonstrated a specialized knowledge of the cultural program. The most cited and appreciated performances came from the areas of music, exhibitions, and theatre. According to the perceptions of tourists, the tangible assets were clearly detached from the set of attributes of Guimarães, including buildings, churches and chapels, whereas intangible assets were less noted. Overall, Guimarães received a very positive evaluation related to city image and stay and is highly recommended by tourists to friends and relatives.

Cultural tourism in Northwest Portugal – the case of the world heritage site of Guimarães

A cidade de Guimarães, no noroeste português, é um espaço imbuído de um forte significado simbólico e cultural. A acreditação pela U.N.E.S.C.O. do seu centro histórico como Património Cultural da Humanidade, em Dezembro de 2001, contribuiu significativamente para aumentar o seu potencial em termos turísticos. Na realidade, desde aquela data, tem-se assistido a um aumento sustentado do número de visitantes. O presente capítulo debruça-se sobre a análise de alguns resultados de um inquérito por questionário aplicado aos residentes do município de Guimarães com o objetivo de avaliar a sua perceção dos benefícios que a atividade turística pode trazer. O inquérito foi implementado entre Janeiro e Março de 2010. Os resultados mostram que aqueles revelam uma perceção favorável dos impactos do turismo e que esta perceção está correlacionada com a idade e o nível de instrução dos inquiridos.

OncologiaPediatrica.org e TalkingAboutCancer.org: A importância dos media participativos na mobilização para a cidadania na luta contra o cancro

O presente estudo tem como objectivo averiguar a validade do uso das plataformas participativas online em acções de cidadania que contribuam na luta contra o cancro. Estas plataformas são frequentemente associadas ao entretenimento; nesse sentido, pretende-se não só testar a supracitada aplicação a outros domínios como o da saúde, mas de igual forma contribuir para uma percepção expandida do potencial destas junto do seu universo de utilizadores. A investigação baseia-se na construção de uma rede solidária online que contribua para a aproximação de cidadãos que estão directa ou indirectamente envolvidos na problemática da oncologia, disponibilizando ao indivíduo meios que o ajudem a contrariar sentimentos de impotência e fatalidade e a ausência de capacidade de mobilização e de cidadania. No âmbito deste percurso de investigação, foi desenvolvida e implementada a plataforma OncologiaPediatrica.org, que teve como primeira missão confirmar a hipótese de o Design Multimédia poder contribuir para a informação, apoio e partilha de testemunhos entre familiares, amigos e doentes na luta contra o cancro pediátrico. Esta plataforma baseia-se num sistema centralizado, ou seja, a organização, política e gestão dos conteúdos informativos do site respeitam uma estrutura hierárquica piramidal. Os resultados do site OncologiaPediatrica.org e os desenvolvimentos tecnológicos conducentes ao florescimento das redes sociais e Web 2.0, entretanto ocorridos, exigiram um reequacionamento da abordagem anteriormente adoptada, por forma a tornar o projecto mais eficaz perante as realidades entretanto surgidas. Neste sentido, foi desenvolvido um protótipo, disponível em TalkingAboutCancer.org, mais descentralizado e aberto à participação da comunidade. O actual estudo conta com o apoio do Instituto Português de Oncologia do Porto. Presentemente averigua-se, junto dos doentes e profissionais de saúde deste hospital, de que forma os media participativos podem ajudar os cidadãos na luta contra o cancro. Os primeiros resultados da investigação são apresentados no presente artigo.