997 resultados para 7140-309


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The topography of the tegument of Echinostoma caproni adults collected from high (mice) and low (rats) compatible hosts was compared by SEM. In the oral (OS) and the ventral sucker (VS) areas, a worm age-host species interaction was found with regard to the density of spines. There was a decrease in the density of spines in the adults collected from mice, whereas an increase occurred in the OS area in worms from rats over time. The tegumentary spines in adults from mice became larger and blunter. Some spines from the VS area in adults from mice at 4 wpi were multipointed. The spines of adults from rats were sharper, not covered by the tegument and no multipointed spines were observed. We detected a greater level of actin gene expression in the adults collected from rats. These facts suggest that the low compatible host induces an increased turnover of tegumentary spines. (C) 2010 Elsevier Inc. All rights reserved.

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This work presents a review of applicable sewer rehabilitation options using trenchless technology in Malaysia. The typical problems faced in wastewater collection systems are analysed and factors that determine the selection method are outlined. This study also highlights the necessary steps to be taken prior to the rehabilitation work. The trenchless technology reviewed here comprises repair, renovation and replacement options. The cost-effectiveness of different rehabilitation methods was identified to assess the economic viability of various options in the Malaysian context. This study reveals that not all the trenchless technologies available in the market are suitable for use in Malaysia, mainly due to incompatibility of the rehabilitation materials used. Furthermore, as trenchless rehabilitation generally involves higher capital outlay than open-cut methods, the choice of rehabilitation method has to be made on a case-to-case basis.

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Despite calls that the school science curriculum should develop among students an ability to understand and respond critically to science-related media reports, very little research has been directed toward an important matter relevant to that aim, namely, how children and young people, untutored, react to science in the news. This study sought, in the context of media coverage of the debate surrounding the planetary status of Pluto, to explore this issue. A questionnaire, completed by 350 students aged between eight and 18, showed just over half of the children and young people were able to write relevantly about the subject though it was the gist not the detail of the story they recounted. There was evidence, nonetheless, that this media-acquired information functioned as active rather than passive knowledge. Students demonstrated relatively few misconceptions and those presented were predominately pre-existing rather than media-derived. As with the wider public, many of the children and young people held strong opinions on Pluto's loss of planethood. Such responses diminished with age, however, with older students expressing a degree of indifference. The paper concludes with a discussion of some implications of the research findings for science instruction.

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Instead of abolishing internal border controls in 1993, the European Union (EU) replaced them with VAT and statistical requirements that appear to be just as onerous. For Dutch businesses, the compliance costs of the new requirements are, on average, 5 per cent of the value of their intra-EU trade. The figure is probably higher for other EU Member States. Obviously, the costs constitute a (differentiated) border tax that impedes intra-EU trade. The article analyses the determinants of the compliance costs, as well as their effect on intra-EU trade intensity. The article submits that the differential compliance costs violate the non-discrimination provisions of the EC Treaty. Suggestions are made to reduce them.

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Self-help (or mutual aid) processes play a substantial role in the reintegration of stigmatized individuals, in particular, a substantial self-help movement has developed around addiction recovery. Prisoners and ex-prisoners have also established self-help groups around the world. This paper focuses in particular on the role of self-help principles and practices among “politically motivated” former prisoners from all sides of the Northern Irish conflict. The concept of self-help and its application to former prisoners are analysed theoretically, then applied to the Northern Irish case study through a series of interviews with ex-prisoners whose incarceration has been related to the conflict in Northern Ireland. We draw on the implications of this case study for wider issues of reintegration for politically motivated and ordinary prisoners.

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Coral reef fish communities in the Seychelles are highly diverse and remain less affected by the direct impacts of human activities than those on many other coral reefs in the Indian Ocean. These factors make them highly suitable for a detailed survey of the impacts of the 1998 mass coral mortality, which devastated the coral faunas of the region. Using underwater visual census (UVC) techniques, fish communities were sampled in three localities in the southern Seychelles and one locality in the northern (granitic) Seychelles. Initial surveys were undertaken from the latter site in 1997. Surveys were undertaken at all sites during the coral bleaching episode in 1998 prior to any major changes in the reef fish communities. Repeat surveys were undertaken in 1999 one year after the coral mortality. Over 250 fish species were sampled from 35 families. Results suggest that changes in the overall fish community structures are not great, despite massive changes in the benthic cover. Significant changes have been observed in a number of individual species. These include those most heavily dependent on live coral cover for shelter or sustenance. Future potential changes are discussed, and potential management interventions are considered. (C) 2002 Elsevier Science Ltd. All rights reserved.