3,606 research outputs found

    A prova de exercício cárdio-pulmonar e o prognóstico cirúrgico do cancro do pulmão

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    Resumo: Os autores procuram dar mais um contributo para a avaliação pré-operatória dos doentes com carcinoma de não pequenas células que vão ser sujeitos a cirurgia de ressecção pulmonar.Trata-se de um estudo prospectivo onde foi avaliado o resultado da cirurgia em termos de complicações ocorridas nos 30 dias a seguir à operação. Os autores definiram cada uma das complicações (óbito, enfarte do miocárdio, insuficiências respiratória, cardíaca e renal, embolia pulmonar, pneumonia e septicemia) e ainda analisaram 3 dessas complicações em separado (óbito, enfarte do miocárdio e insuficiência respiratória), as quais designaram por âfraco resultadoâ.Antes da cirurgia, foram avaliados 99 doentes (34 pneumectomias, 56 lobectomias, 6 bilobectomias e 3 ressecções atípicas) com espirometria (FEV1 em litros) e consumo de oxigénio no exercício máximo (VO2peak). Só 26 doentes tinham valores funcionais considerados borderline (FEV1 < 1,5 litros para lobectomia e < 2,0 litros para pneumectomia). Nos resultados apresentados observámos os seguintes valores médios: FEV1=2,06 litros; FEV1=80,4% do valor teórico; VO2peak=18,8 ml/kg/min ou 88,3% do valor teórico. Só existiram 4 óbitos (4%) e 21 doentes tiveram uma ou mais das complicações referenciadas.Os autores não encontraram relação significativa entre as complicações pós-operatórias e o FEV1 em litros. Verificaram ainda que o VO2peak em percentagem do valor teórico previa melhor um âfraco resultadoâ do que o mesmo parâmetro em valor absoluto.Em relação aos óbitos, um dos doentes tinha sido submetido a quimioterapia, o que dificultou a avaliação do desfecho. Nos restantes 3 óbitos, todos os doentes tinham um VO2peak < 62% do valor teórico. Dois dos 3 doentes com VO2peak < 50% tiveram um âfraco resultadoâ. Com VO2peak > 75% só 3 em 20 doentes é que tiveram um âfraco resultadoâ.Apesar de reconhecerem a necessidade de mais e maiores estudos, os autores concluem que VO2peak é importante para prever complicações como óbito, enfarte do miocárdio ou insuficiência respiratória, principalmente se é referido em percentagem do valor teórico. O limite âseguroâ situar-se-ia entre 50 e 60% do valor previsto

    Irradiation of benzene molecules by ion-induced and light-induced intense fields

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    Benzene, with its sea of delocalized π\pi-electrons in the valence orbitals, is identified as an example of a class of molecules that enable establishment of the correspondence between intense ion-induced and laser-light-induced fields in experiments that probe ionization dynamics in temporal regimes spanning the attosecond and picosecond ranges.Comment: 4 ps figure

    Mitochondrial ROS regulate oxidative damage and mitophagy but not age-related muscle fiber atrophy

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    Age-related loss of skeletal muscle mass and function is a major contributor to morbidity and has a profound effect on the quality of life of older people. The potential role of age-dependent mitochondrial dysfunction and cumulative oxidative stress as the underlying cause of muscle aging remains a controversial topic. Here we show that the pharmacological attenuation of age-related mitochondrial redox changes in muscle with SS31 is associated with some improvements in oxidative damage and mitophagy in muscles of old mice. However, this treatment failed to rescue the age-related muscle fiber atrophy associated with muscle atrophy and weakness. Collectively, these data imply that the muscle mitochondrial redox environment is not a key regulator of muscle fiber atrophy during sarcopenia but may play a key role in the decline of mitochondrial organelle integrity that occurs with muscle aging

    Predator Mimicry: Metalmark Moths Mimic Their Jumping Spider Predators

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    Cases of mimicry provide many of the nature's most convincing examples of natural selection. Here we report evidence for a case of predator mimicry in which metalmark moths in the genus Brenthia mimic jumping spiders, one of their predators. In controlled trials, Brenthia had higher survival rates than other similarly sized moths in the presence of jumping spiders and jumping spiders responded to Brenthia with territorial displays, indicating that Brenthia were sometimes mistaken for jumping spiders, and not recognized as prey. Our experimental results and a review of wing patterns of other insects indicate that jumping spider mimicry is more widespread than heretofore appreciated, and that jumping spiders are probably an important selective pressure shaping the evolution of diurnal insects that perch on vegetation

    Effect of near-terminus subglacial hydrology on tidewater glacier submarine melt rates

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    Submarine melting of Greenlandic tidewater glacier termini is proposed as a possiblemechanism driving their recent thinning and retreat. We use a general circulation model, MITgcm, tosimulate water circulation driven by subglacial discharge at the terminus of an idealized tidewater glacier.We vary the spatial distribution of subglacial discharge emerging at the grounding line of the glacier andexamine the effect on submarine melt volume and distribution. We find that subglacial hydrology exerts animportant control on submarine melting; under certain conditions a distributed system can induce a factor5 more melt than a channelized system, with plumes from a single channel inducing melt over only alocalized area. Subglacial hydrology also controls the spatial distribution of melt, which has the potential tocontrol terminus morphology and calving style. Our results highlight the need to constrain near-terminussubglacial hydrology at tidewater glaciers if we are to represent ocean forcing accurately

    The feasibility of determining the impact of primary health care research projects using the Payback Framework

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    <p>Abstract</p> <p>Background</p> <p>Primary health care research is under pressure to be accountable to funders in terms of benefits for practice and policy. However, methods to assess the impact of primary health care research must be appropriate to use with the diverse topics, settings and approaches of this sector. This project explored the feasibility of using the Buxton and Hanney Payback Framework to determine the impact of a stratified random sample (n = 4) of competitively funded, primary health care research projects.</p> <p>Methods</p> <p>The project conducted telephone interviews based on the Payback Framework with leaders of the research teams and nominated users of their research, used bibliometric methods for assessing impact through publication outputs and obtained documentary evidence of impact where possible. The purpose was to determine the effectiveness of the data collection methods and the applicability of the Payback Framework, and any other issues which arose around the assessment of impact of primary health care research.</p> <p>Results and discussion</p> <p>The thirteen interviews were resource intensive to organise conduct and analyse but provided better information about impact than bibliometric analysis or documentary analysis. Bibliometric analysis of the papers published from the four projects was hampered by the inclusion of only one of the journals in major citation indexes. Document analysis provided more evidence of dissemination than of impact.</p> <p>The payback framework and logic model were a sound basis for assessing impact. Chief investigators and nominated users of research provided substantial information relevant to the impact categories closest to their spheres of influence and awareness, but less about the impact their research had on the wider health sector, population health or economic benefits. An additional category of impact emerged from the interviews, that of strengthening research networks which could enhance the impact of later work. The framework provided rich information about the pathways to impact, better understanding of which may enhance impact.</p> <p>Conclusion</p> <p>It is feasible to use the Buxton and Hanney Payback framework and logic model to determine the proximal impacts of primary health care research. Though resource intensive, telephone interviews of chief investigators and nominated users provided rich information.</p

    The effectiveness of interventions to change six health behaviours: a review of reviews

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    Background: Several World Health Organisation reports over recent years have highlighted the high incidence of chronic diseases such as diabetes, coronary heart disease and cancer. Contributory factors include unhealthy diets, alcohol and tobacco use and sedentary lifestyles. This paper reports the findings of a review of reviews of behavioural change interventions to reduce unhealthy behaviours or promote healthy behaviours. We included six different health-related behaviours in the review: healthy eating, physical exercise, smoking, alcohol misuse, sexual risk taking (in young people) and illicit drug use. We excluded reviews which focussed on pharmacological treatments or those which required intensive treatments (e. g. for drug or alcohol dependency). Methods: The Cochrane Library, Database of Abstracts of Reviews of Effectiveness (DARE) and several Ovid databases were searched for systematic reviews of interventions for the six behaviours (updated search 2008). Two reviewers applied the inclusion criteria, extracted data and assessed the quality of the reviews. The results were discussed in a narrative synthesis. Results: We included 103 reviews published between 1995 and 2008. The focus of interventions varied, but those targeting specific individuals were generally designed to change an existing behaviour (e. g. cigarette smoking, alcohol misuse), whilst those aimed at the general population or groups such as school children were designed to promote positive behaviours (e. g. healthy eating). Almost 50% (n = 48) of the reviews focussed on smoking (either prevention or cessation). Interventions that were most effective across a range of health behaviours included physician advice or individual counselling, and workplace- and school-based activities. Mass media campaigns and legislative interventions also showed small to moderate effects in changing health behaviours. Generally, the evidence related to short-term effects rather than sustained/longer-term impact and there was a relative lack of evidence on how best to address inequalities. Conclusions: Despite limitations of the review of reviews approach, it is encouraging that there are interventions that are effective in achieving behavioural change. Further emphasis in both primary studies and secondary analysis (e.g. systematic reviews) should be placed on assessing the differential effectiveness of interventions across different population subgroups to ensure that health inequalities are addressed.</p

    Behaviour and Climate Change: Consumer Perceptions of Responsibility

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    This paper explores the under-researched notion of consumer responsibility, a potentially significant influence on consumer behaviour that marketers and policymakers may be able to harness as they attempt to respond to environmental challenges such as climate change. The paper uses data derived from a commercially motivated survey (n = 1513) to explore domestic consumption behaviours most closely associated with the issue of disruptive climate change. A measure of 'General Environmental Responsiveness' (GER) is used to test: (1) the effects of consumers both taking responsibility for their actions and placing responsibility on others for the consequences of their consumption behaviour; and (2) whether sociodemographic variables can aid the targeting of consumers by the level and type of responsibility and pro-environmental behavioural intentions expressed. The study's findings demonstrate clear, if not strong, relationships between consumer conceptions of responsibilities for causing and tackling climate change and environment-related consumer behaviour. The study's implications both challenge accepted wisdom about environment-related consumer behaviour and suggest avenues for future research
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