294 resultados para optimistic


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In the United States and several other countries., the development of population viability analyses (PVA) is a legal requirement of any species survival plan developed for threatened and endangered species. Despite the importance of pathogens in natural populations, little attention has been given to host-pathogen dynamics in PVA. To study the effect of infectious pathogens on extinction risk estimates generated from PVA, we review and synthesize the relevance of host-pathogen dynamics in analyses of extinction risk. We then develop a stochastic, density-dependent host-parasite model to investigate the effects of disease on the persistence of endangered populations. We show that this model converges on a Ricker model of density dependence under a suite of limiting assumptions, including. a high probability that epidemics will arrive and occur. Using this modeling framework, we then quantify: (1) dynamic differences between time series generated by disease and Ricker processes with the same parameters; (2) observed probabilities of quasi-extinction for populations exposed to disease or self-limitation; and (3) bias in probabilities of quasi-extinction estimated by density-independent PVAs when populations experience either form of density dependence. Our results suggest two generalities about the relationships among disease, PVA, and the management of endangered species. First, disease more strongly increases variability in host abundance and, thus, the probability of quasi-extinction, than does self-limitation. This result stems from the fact that the effects and the probability of occurrence of disease are both density dependent. Second, estimates of quasi-extinction are more often overly optimistic for populations experiencing disease than for those subject to self-limitation. Thus, although the results of density-independent PVAs may be relatively robust to some particular assumptions about density dependence, they are less robust when endangered populations are known to be susceptible to disease. If potential management actions involve manipulating pathogens, then it may be useful to. model disease explicitly.

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In Queensland, Australia, there is presently a high level of interest in long-rotation hardwood plantation investments for sawlog production, despite the consensus in Australian literature that such investments are not financially viable. Continuing genetics, silviculture and processing research, and increasing awareness about the ecosystem services generated by plantations, are anticipated to make future plantings profitable and socio-economically desirable in many parts of Queensland. Financial and economic models of hardwood plantations in Queensland are developed to test this hypothesis. The economic model accounts for carbon sequestration, salinity amelioration and other ecosystem service values of hardwood plantations. A carbon model estimates the value of carbon sequestered, while salinity and other ecosystem service values are estimated by the benefit transfer method. Where high growth rates (20-25 m(3) ha(-1) year(-1)) are achievable, long-rotation hardwood plantations are profitable in Queensland Hardwood Regions 1, 3 and 7 when rural land values are less than $2300/ha. Under optimistic assumptions, hardwood plantations growing at a rate of 15 in 3 ha-1 year 1 are financially viable in Hardwood Regions 2, 4 and 8, provided land values are less than $1600/ha. The major implication of the economic analysis is that long-rotation hardwood plantation forestry is socio-economically justified in most Hardwood Regions, even though financial returns from timber production may be negative. (c) 2003 Elsevier B.V. All rights reserved.

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This study investigated an Australian antidrug campaign that targeted adolescents directly and indirectly via recruiting parents into drug prevention. Eighty-six parent-child dyads completed surveys measuring campaign evaluations, discussions about drugs, and beliefs about risks to self (own child) and to the average young Australian. Adolescents were optimistic about risks, and media impact was evident only in perceptions of risk to others. Parents were less optimistic, and perceptions of campaign quality predicted perceived risk to own child and discussion about drugs. However, this was moderated by negative affect associated with the campaign. There was some evidence that discussions influenced adolescents' perceptions of personal risk. This demonstrates the importance of individual responses and communication processes in determining the impact of persuasive media messages.

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There is strong evidence from twin and family studies indicating that a substantial proportion of the heritability of susceptibility to ankylosing spondylitis (AS) and its clinical manifestations is encoded by non-major-histocompatibility-complex genes. Efforts to identify these genes have included genomewide linkage studies and candidate gene association studies. One region, the interleukin (IL)-I gene complex on chromosome 2, has been repeatedly associated with AS in both Caucasians and Asians. It is likely that more than one gene in this complex is involved in AS, with the strongest evidence to date implicating IL-IA. Identifying the genes underlying other linkage regions has been difficult due to the lack of obvious candidates and the low power of most studies to date to identify genes of the small to moderate magnitude that are likely to be involved. The field is moving towards genomewide association analysis, involving much larger datasets of unrelated cases and controls. Early successes using this approach in other diseases indicates that it is likely to identify genes in common diseases like AS, but there remains the risk that the common-variant, common-disease hypothesis will not hold true in AS. Nonetheless, it is appropriate for the field to be cautiously optimistic that the next few years will bring great advances in our understanding of the genetics of this condition.

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This special issue revisits the relationship between women, work and technology, focusing specifically on gender equity in information technology (IT) employment. Along with theoretical contestation over the broader relationship between gender and technology, arguments about the prospects for women in IT employment have ranged from optimistic to pessimistic extremes. On the one hand, optimists have envisaged a more gender-egalitarian workforce based on new occupations lacking traditional gender markers, and 'young' firms offering positive flexibilities and equal employment opportunity protections. On the other hand, pessimists anticipate that ongoing male dominance over tedmology and competitive pressures in the IT sector will ensure that the most prestigious and highly rewarded jobs remain concentrated in male hands, even as teclmologies and jobs are themselves transformed.

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Ainda que um conjunto de atributos confira ao rádio um grande potencial para chamar a atenção do ouvinte e envolvê-lo em sua mensagem; ainda que o rádio seja uma das mídias com maior penetração nos domicílios e automóveis do Brasil; ainda que a adaptação do rádio às tecnologias digitais trace perspectivas otimistas para o meio; ainda que a sociedade moderna esteja criando indivíduos extremamente ocupados, que passam mais tempo no trabalho e nos automóveis do que em casa, abrindo espaço para o único meio que permite a execução de outras tarefas enquanto é consumido; comercialmente, o rádio enfrenta grandes dificuldades para atrair investimentos publicitários principal fonte de renda do meio. Nesse sentido, esta pesquisa exploratória pretende identificar e analisar os fatores que influenciam o baixo posicionamento do rádio no ranking dos investimentos publicitários. Para tanto, serão analisadas duas questões consideradas fundamentais: o emprego das possibilidades expressivas e persuasivas da publicidade radiofônica nos anúncios veiculados pelas emissoras e a percepção dos profissionais envolvidos na operacionalização da publicidade radiofônica sobre a atividade publicitária no rádio.

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Este estudo teve por objetivo verificar a capacidade de otimismo, de suporte social e de valores do trabalho serem preditores de bem estar subjetivo, bem como analisar as relações de variáveis demográficas com essas variáveis de estudo, descrevê-las e examinar as relações entre elas. A amostra consistiu de 47 homens e de 101 mulheres com idade média de 41,00 anos (DP =10,72) que buscavam apoio em instituição para sua transição profissional. O instrumento de coleta de dados foi um questionário de autopreenchimento composto por cinco medidas que aferiram as variáveis incluídas no estudo: otimismo, percepção de suporte social, valores do trabalho, satisfação geral com a vida e afetos positivos e negativos, bem como variáveis demográficas: sexo, idade, estudo, trabalho, voluntariado, estado civil e permanência na instituição. Foram realizadas análises estatísticas descritivas, testadas diferenças entre médias, correlações, análise de variância e calculados modelos de regressão linear múltipla. As relações das variáveis de estudo com variáveis demográficas revelaram que as pessoas que não estudam percebem ter mais suporte prático e dão mais importância a motivações de autopromoção e de prestígio do que as que estudam. Os mais jovens com até 30 anos relataram que se percebem tendo mais apoio emocional e prático do que os mais velhos. Com o avanço da idade diminuem as percepções de suporte emocional e prático, contudo as pessoas com mais de 50 anos revelaram menos afetos negativos e maior satisfação com a vida do que os mais jovens. Casados revelaram dar menos importância do que separados, divorciados, viúvos, etc. à estabilidade no trabalho e segurança financeira; solteiros revelaram ter mais afetos negativos do que os casados. Homens relataram se sentir mais satisfeitos com a vida, ter mais afetos positivos e menos afetos negativos que mulheres. Quem realiza trabalho voluntário revelou ser mais otimista e ter menos afetos negativos do que aqueles que não realizam. Os dados revelaram que os pesquisados têm um bom nível de otimismo e uma percepção de suporte emocional maior do que a percepção de suporte prático; são motivados, principalmente por metas de realização no trabalho e de estabilidade e segurança financeira; sentem-se indiferentes quanto à satisfação com a vida; apresentam afetos positivos um pouco acima da indiferença; contudo sentem poucos afetos negativos. Disso decorre que um pouco mais de dois terços dos pesquisados apresentaram predominância de estados emocionais positivos sobre os negativos. O otimismo foi a variável que estabeleceu associações mais altas e em maior quantidade; correlacionou positivamente com valores de realização no trabalho, com valores de relações sociais, com valores do trabalho de prestígio, com satisfação com a vida e com afetos positivos; e correlacionou negativamente com afetos negativos. A percepção de suporte emocional correlacionou positivamente com valores de prestígio, afetos positivos e com satisfação com a vida; e correlacionou negativamente com afetos negativos. Percepção de suporte prático não apresentou correlações significativas com nenhuma variável de estudo. Afetos positivos correlacionaram-se positivamente com valores do trabalho de relações sociais e com valores do trabalho de prestígio. A partir da análise de três modelos preditivos encontrou-se que otimismo e suporte emocional repercutem positivamente sobre a satisfação com a vida e sobre afetos positivos. Otimismo repercute negativamente sobre afetos negativos. Valores do trabalho de prestígio repercutem positivamente sobre afetos positivos. Valores de estabilidade repercutem negativamente sobre satisfação com a vida e sobre afetos positivos; e positivamente sobre afetos negativos. Os resultados deste estudo mostraram que o estado otimista é um poderoso fator de impacto positivo sobre o estado de saúde denominado bem estar subjetivo.(AU)

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We propose a method to determine the critical noise level for decoding Gallager type low density parity check error correcting codes. The method is based on the magnetization enumerator (¸M), rather than on the weight enumerator (¸W) presented recently in the information theory literature. The interpretation of our method is appealingly simple, and the relation between the different decoding schemes such as typical pairs decoding, MAP, and finite temperature decoding (MPM) becomes clear. Our results are more optimistic than those derived via the methods of information theory and are in excellent agreement with recent results from another statistical physics approach.

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We determine the critical noise level for decoding low density parity check error correcting codes based on the magnetization enumerator , rather than on the weight enumerator employed in the information theory literature. The interpretation of our method is appealingly simple, and the relation between the different decoding schemes such as typical pairs decoding, MAP, and finite temperature decoding (MPM) becomes clear. In addition, our analysis provides an explanation for the difference in performance between MN and Gallager codes. Our results are more optimistic than those derived via the methods of information theory and are in excellent agreement with recent results from another statistical physics approach.

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We propose a method based on the magnetization enumerator to determine the critical noise level for Gallager type low density parity check error correcting codes (LDPC). Our method provides an appealingly simple interpretation to the relation between different decoding schemes, and provides more optimistic critical noise levels than those reported in the information theory literature.

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The replica method, developed in statistical physics, is employed in conjunction with Gallager's methodology to accurately evaluate zero error noise thresholds for Gallager code ensembles. Our approach generally provides more optimistic evaluations than those reported in the information theory literature for sparse matrices; the difference vanishes as the parity check matrix becomes dense.

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Universities which set up online repositories for the management of learning and teaching resources commonly find that uptake is poor. Tutors are often reluctant to upload their materials to e-repositories, even though the same tutors are happy to upload resources to the virtual learning environment (e.g. Blackboard, Moodle, Sakai) and happy to upload their research papers to the university’s research publications repository. The paper reviews this phenomenon and suggests constructive ways in which tutors can be encouraged to engage with an e-repository. The authors have recently completed a major project “Developing Repositories at Worcester” which is part of a group of similar projects in the UK. The paper includes the feedback and the lessons learned from these projects, based on the publications and reports they have produced. They cover ways of embedding repository use into institutional working practice, and give examples of different types of repository designed to meet the needs of those using different kinds of learning and teaching resources. As well as this specific experience, the authors summarise some of the main findings from UK publications, in particular the December 2008 report of Joint Information Systems Committee: Good intentions: improving the evidence base in support of sharing learning materials and Online Innovation in Higher Education, Ron Cooke’s report to a UK government initiative on the future of Higher Education. The issues covered include the development of Web 2.0 style repositories rather than conventionally structured ones, the use of tags rather than metadata, the open resources initiative, the best use for conventional repositories, links to virtual learning environments, and the processes for the management and support of repositories within universities. In summary the paper presents an optimistic, constructive view of how to embed the use of e-repositories into the working practices of university tutors. Equally, the authors are aware of the considerable difficulties in making progress and are realistic about what can be achieved. The paper uses evidence and experience drawn from those working in this field to suggest a strategic vision in which the management of e-learning resources is productive, efficient and meets the needs of both tutors and their students.

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There is lots of evidence that innovating firms are persistently more profitable than non-innovators, but little agreement on why this is the case. It may be because innovators are somehow able to protect their new products from the competition which normally erodes profits, or because innovating firms have superior capabilities and are able to introduce multiple innovations over time. And very little is known about the relationship between innovation, external ownership and profitability, despite the fact that foreign-owned firms are frequently highly innovative and very profitable. This paper considers the relationship between innovation, ownership and profitability for a panel of manufacturing plants in Ireland and Northern Ireland. We consider the link between innovation and profits separately for innovators and non-innovators, and for indigenous innovators and non-innovators and externally-owned plants. We also consider the determinants of innovation over the distribution of plant-level profitability, and find that the determinants of profitability – including innovation and external ownership – are quite different for low and high-profitability plants. We find support for the view that innovators and non-innovators have different profitability determinants, and that externally-owned plants have their profitability determined in a quite different way from indigenous enterprises. For indigenous non-innovators only the sector matters. Profitability in these enterprises is dictated largely by the industry they are in, with plants having virtually no means of differentiating their profitability from the norms of the industry. By contrast, indigenously-owned innovators are able to differentiate their profit performance from industry norms to some extent. Absolute size matters (negatively) and they get a strong boost from product innovation, but having a high market share does not matter for the profitability of indigenously-owned innovators. Externally-owned plants have a quite different set of profitability determinants from both of these groups. What matters for these plants is not the boost they get from innovating (there is none) but instead their position in the domestic market – a high market share boosts profitability. In policy terms our results suggest both optimistic and cautionary messages. On the positive side our results suggest that efforts to promote innovation activity among indigenously-owned plants are likely to have significant longer term benefits through their capability effects. For the development agencies in Ireland this is a reassuring result. On the more negative side, the lack of any relationship in our models between the innovation activities of externally-owned plants and their (profitability) performance raises potential concerns. This finding may reflect the lack of linkages between externally-owned plants and their Irish resource base, in turn raising some worrying issues about the ‘embeddedness’ of much FDI into Ireland and therefore its ‘stickiness’ in the face of Ireland’s increasing high relative cost base.

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Glioblastoma multiforme (GBM) is a malignant brain tumour for which there is currently no effective treatment regime. It is thought to develop due to the overexpression of a number of genes, including the epidermal growth factor receptor (EGFR), which is found in over 40% of GBM. Novel forms of treatment such as antisense therapy may allow for the specific inhibition of aberrant genes and thus they are optimistic therapies for future treatment of GBM. Oligodeoxynucleotides (ODNs) are small pieces of DNA that are often modified to increase their stability to nucleases and can be targeted to the aberrant gene in order to inhibit it and thus prevent its transcription into protein. By specifically binding to mRNA in an antisense manner, they can bring about its degradation by a variety of mechanisms including the activation of RNase H and thus have great potential as therapeutic agents. One of the main drawbacks to the utilisation of this therapy so far is the lack of techniques that can successfully predict accessible regions on the target mRNA that the ODNs can bind to. DNA chip technology has been utilised here to predict target sequences on the EGFR mRNA and these ODNs (AS 1 and AS2) have been tested in vitro for their stability, uptake into cells and their efficacy on cellular growth, EGFR protein and mRNA. Studies showed that phosphorothioate and 2'O-methyl ODNs were significantly more stable than phosphodiester ODNs both in serum and serum-free conditions and that the mechanism of uptake into A431 cells was temperature dependent and more efficient with the use of optimised lipofectin. Efficacy results show that AS 1 and AS2 phosphorothioate antisense ODNs were capable of inhibiting cell proliferation by 69% ±4% and 65% ±4.5% respectively at 500nM in conjunction with a non-toxic dose of lipofectinTM used to enhance cellular delivery. Furthermore, control ODN sequences, 2' O-methyl derivatives and a third ODN sequence, that was found not to be capable of binding efficiently to the EGFR mRNA by DNA chip technology, showed no significant effect on cell proliferation. AS 1 almost completely inhibited EGFR protein levels within 48 hours with two doses of 500nM AS 1 with no effect on other EGFR family member proteins or by control sequences. RNA analysis showed a decrease in mRNA levels of 32.4% ±0.8% but techniques require further optimisation to confirm this. As there are variations found between human glioblastoma in situ and those developed as xenografts, analysis of effect of AS 1 and AS2 was performed on primary tumour cell lines derived from glioma patients. ODN treatment showed a specific knockdown of cell growth compared to any of the controls used. Furthermore, combination therapies were tested on A431 cell growth to determine the advantage of combining different antisense approaches and that of conventional drugs. Results varied between the combination treatments but indicated that with optimisation of treatment regimes and delivery techniques that combination therapies utilising antisense therapies would be plausible.

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This study is a consumer-survey conducted with former Marriage Guidance Council clients. The objectives were to identify and examine why they chose the agency, what their expectations and experiences were of marital counselling and whether anything was achieved. The material was derived from tape recorded interviews with 51 former M.G. clients (17 men and 34 women) from 42 marriages and with 21 counsellors; data from written material and a card-sort completed by the research sample; and the case record sheets of the research population (174 cases). The results from the written data of clients showed that 49% were satisfied with counselling, 25.5% were satisfied in some ways but not in others, and 25.5% were dissatisfied. Forty-six percent rated they had benefited from counselling, either a great deal or to some degree, 4% were neutral and 50% recorded they had not benefited. However the counsellors' assessments were more optimistic. It was also ascertained that 50% of the research sample eventually separated or divorced subsequent to counselling. A cross-check revealed that the majority who rated they were satisfied with counselling were those who remained married, whilst dissatisfied clients were the ones who unwillingly separated or divorced. The study then describes, discusses and assesses the experiences of clients in the light of these findings on a number of dimensions. From this it was possible to construct a summary profile of a "successful" client describing the features which would contribute to "success". Two key themes emerged from the data. (1) the discrepancy between clients expectations and the counselling offered, which included mis­ match over the aims and methods of counselling, and problem definition; and (2) the importance of the client/counsellor relationship. The various implications for the agency are then discussed which include recommendations on policy, the training of counsellors and further research.