246 resultados para Rhinella margaritifera group


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1. Until recently the status of Margaritifera margaritifera L. in Northern Ireland was not well documented. This paper presents the results of field surveys conducted in 1990/'91 and in 1996 at over 200 sites covering all major river systems in Northern Ireland. 2.Margaritifera populations in Northern Ireland were recorded at just 20 sites mainly located in the west of the province. Formerly many rivers supported vast numbers of mussels but anecdotal evidence points to periods of major declines in mussel populations since the turn of the century. 3. The absence of mussels smaller than 30 mm in length at most sites suggests very little or no recruitment during the past decade. During the surveys, deteriorating water quality, habitat disturbance and pearl fishing were recorded and are the major causes of the decline of the freshwater pearl mussel in Northern Ireland. 4. Unless the above problems are alleviated in the very near future, M.margaritifera will probably become extinct in Northern Ireland. © 1998 John Wiley & Sons, Ltd.

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1.Margaritifera margaritifera populations are declining throughout its range, including Ireland, despite legislation designed to protect freshwater pearl mussels and their habitat. A survey of freshwater 2. pearl mussels was carried out on rivers in County Donegal, north-west Ireland, to determine the current distribution, size and density of M. margaritifera populations, as well as to identify potential threats to mussels there. 3. The survey revealed the freshwater pearl mussel to be widespread, particularly in the western half of the county. However, densities of mussels at most sites are low, with just two sites having mussel densities of over 5?m-2. Furthermore, the species appears to be absent from a number of sites from which it had been previously recorded. 4. According to the literature, there is a long history of pearl fishing in Co. Donegal and neighbouring counties. Evidence from heaps of shells found on the river bed and banks at several sites and recent anecdotal reports from local people suggest pearl fishing is being practised on all rivers investigated during the present study. The main conservation requirements for 5. M. margaritifera populations in Donegal are to maintain water quality at its present high standard and, as pearl fishing appears to be a widespread and immediate threat to the remaining mussel populations, to enforce existing legislation designed to protect M. margaritifera.

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Molecular mechanics calculations have been used to model the geometries of the complexes of Group I metal ions with calix[n]arenes (n = 4,5). A simple procedure in which the calixarene atoms are assigned partial charges on the basis of AM1 calculations and the metal ions are allowed to bind electrostatically to the calixarenes produces surprising good results when the resulting structures are compared to known crystallographic data on the complexes. Encapsulated solvent molecules and/or counterions can be included in the calculations and, indeed, are necessary to reproduce the X-ray data.

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We examine support for policies affecting indigenous ethnic minorities in Chile. Specifically, we examine the role of national group definitions that include the largest indigenous group—the Mapuche—in different ways. Based on questionnaire data from nonindigenous Chilean students (N = 338), we empirically distinguish iconic inclusion, whereby the Mapuche are seen as an important part of Chile's history and identity on the one hand, from egalitarian inclusion, which represents the Mapuche as citizens of equal importance to the nonindigenous majority on the other. Both forms of inclusion positively predict support for indigenous rights, independent of participants' political affiliation, strength of national identification, and social distance. A second study (N = 277) replicates this finding whilst controlling for right-wing authoritarianism, social dominance orientation, blind patriotism, and constructive patriotism. It also finds iconic inclusion to be predictive of a pro-Mapuche position regarding the unrest over the issue of ancestral land in 2009. We conclude that understanding how national identity affects attitudes about minority rights necessitates appreciating the importance of particular meanings of nationality, and not only the strength of identification.

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A study was undertaken to examine the population structure of viridans group streptococci (VGS) in the sputum of adult patients with cystic fibrosis (CF). Freshly expectorated sputa (n=58) from 45 adult CF patients were examined by selective conventional culture on Mitis-Salivarius agar and yielded 190 isolates of VGS. Sequence analyses of the rpnB and 16-23S rRNA ITS genes identified these isolates to belong to 12 species of VGS and included S. anginosus, S. australis, S. cristatus, S. gordonii, S. infantis, S. mitis, S. mutans, S. oralis, S. parasanguinis, S. pneumoniae, S. salivarius and S. sanguinis. The most frequently VGS organism isolated was S. salivarius (47/190; 24.7%), followed by S. mitts (36/190; 19%), S. sanguinis (25/190; 13.2%), S. oralis (20/190; 11.0%), S. pneumoniae (19/190; 10.0%), S. parasanguinis (16/190; 8.4%), S. infantis (11/190; 5.8%), S. gordonii (7/190; 3.7%), S. anginosus (4/190; 2.1%), S. cristatus (2/190; 1.1%), S. australis (1/190; 0.5%), S. mutans (1/190; 0.5%) and S. agalactiae (1/190; 0.5%). All, but four, patients harboured at least one VGS species, which ranged from one to five streptococcal species, with a mean of 2.85 species per patient. There was no clonality at the subspecies level employing ERIC RAPD PCR. Antibiotic susceptibility was determined by Minimum Inhibitory Concentration (MIC) testing against penicillin, erythromycin and ciprofloxacin. Overall, resistance to penicillin with all VGS was 73/190 (38.4%) and 167/190 (87.9%) for erythromycin. With regard to ciprofloxacin, 27/190 (14.2%) were fully resistant, whilst a further 21/190 (11.1%) showed intermediate resistance, which equated to approximately three quarters (74.7%) of isolates being fully sensitive to this agent. In addition, as a comparator control population, we examined antibiotic susceptibility, as above, in a non-CF population comprising 12 individuals (50 VGS isolates), who were not receiving chronic antibiotics. In comparison, 8% and 38% of VGS isolates from non-CF individuals were resistant by disk susceptibility testing to penicillin and erythromycin, respectively. None of the non-CF VGS organisms were resistant to ciprofloxacin, but 42% showed intermediate resistance. (C) 2010 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

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One manifestation of division and the history of conflict in Northern Ireland is the parallel education system that exists for Protestants and Catholics. Although recent decades have seen some advances in the promotion of integrated education, around 95% of children continue to attend schools separated on ethno-religious lines. In 2007 a programme for sharing education was established. Underpinned by intergroup contact theory, and reflecting educational priorities shared by all school sectors, the programme seeks to offer children from different denominational schools an opportunity to engage with each other on a sustained basis. In this article the authors adopt a quantitative approach to examining the impact of participation in the Sharing Education Programme on a range of outcomes (out-group attitudes, positive action tendencies and out-group trust) via, first, intergroup contact (cross-group friendships) and, second, intergroup anxiety. Their findings confirm the value of contact as a mechanism for promoting more harmonious relationships, and affirm the Sharing Education Programme as an initiative that can help promote social cohesion in a society that remains deeply divided.

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The purpose of our two-year follow-up study was to examine the effect of the social components of the work group, such as group absence norms and cohesion, on sickness absence behavior among individuals with varying attitudes toward work attendance. The social components were measured using a questionnaire survey, and data on sickness absence behavior were collected from the employers' records. The study population consisted of 19,306 Finnish municipal employees working in 1,847 groups (78% women). Multilevel Poisson regression modeling was applied. The direct effects of work group characteristics on sickness absence were mostly insignificant. In contrast, both of the social components of a work group had an indirect impact: The more tolerant the group absence norms (at both individual- and cross-level) and the lower the group cohesion (at the individual level), the more the absence behavior of an individual was influenced by his or her attitude toward work attendance. We conclude that work group moderates the extent to which individuals with a liberal attitude toward work attendance actually engage in sickness absence behavior.

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The basic principles of semiconductor photochemistry, particularly using titania as a semiconductor photocatalyst, are discussed. When a platinum group metal or its oxide is deposited onto the surface of a sensitised semiconductor the overall efficiency of the reactions it takes part in are often improved, especially when the deposits are used as hydrogen and oxygen catalysts, respectively. Methods of depositing metal or metal oxide are examined, and a particular focus is given to a photodeposition process that uses a sacrificial electron donor. Platinum group metal and platinum group metal oxide coated semiconductor photocatalysts are prominent in heterogeneous systems that are capable of the photoreduction, oxidation and cleavage of water. There is a recent renaissance in work on water-splitting semiconductor-sensitised photosystems, but there are continued concerns over their irreproducibility, longevity and photosynthetic nature.