184 research outputs found

    Internal deformation of the subducted Nazca slab inferred from seismic anisotropy

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    Within oceanic lithosphere a fossilized fabric is often preserved originating from the time of plate formation. Such fabric is thought to form at the mid-ocean ridge when olivine crystals align with the direction of plate spreading1, 2. It is unclear, however, whether this fossil fabric is preserved within slabs during subduction or overprinted by subduction-induced deformation. The alignment of olivine crystals, such as within fossil fabrics, can generate anisotropy that is sensed by passing seismic waves. Seismic anisotropy is therefore a useful tool for investigating the dynamics of subduction zones, but it has so far proved difficult to observe the anisotropic properties of the subducted slab itself. Here we analyse seismic anisotropy in the subducted Nazca slab beneath Peru and find that the fast direction of seismic wave propagation aligns with the contours of the slab. We use numerical modelling to simulate the olivine fabric created at the mid-ocean ridge, but find it is inconsistent with our observations of seismic anisotropy in the subducted Nazca slab. Instead we find that an orientation of the olivine crystal fast axes aligned parallel to the strike of the slab provides the best fit, consistent with along-strike extension induced by flattening of the slab during subduction (A. Kumar et al., manuscript in preparation). We conclude that the fossil fabric has been overprinted during subduction and that the Nazca slab must therefore be sufficiently weak to undergo internal deformation

    Characteristics of control group participants who increased their physical activity in a cluster-randomized lifestyle intervention trial

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    <p>Abstract</p> <p>Background</p> <p>Meaningful improvement in physical activity among control group participants in lifestyle intervention trials is not an uncommon finding, and may be partly explained by participant characteristics. This study investigated which baseline demographic, health and behavioural characteristics were predictive of successful improvement in physical activity in usual care group participants recruited into a telephone-delivered physical activity and diet intervention trial, and descriptively compared these characteristics with those that were predictive of improvement among intervention group participants.</p> <p>Methods</p> <p>Data come from the Logan Healthy Living Program, a primary care-based, cluster-randomized controlled trial of a physical activity and diet intervention. Multivariable logistic regression models examined variables predictive of an improvement of at least 60 minutes per week of moderate-to-vigorous intensity physical activity among usual care (n = 166) and intervention group (n = 175) participants.</p> <p>Results</p> <p>Baseline variables predictive of a meaningful change in physical activity were different for the usual care and intervention groups. Being retired and completing secondary school (but no further education) were predictive of physical activity improvement for usual care group participants, whereas only baseline level of physical activity was predictive of improvement for intervention group participants. Higher body mass index and being unmarried may also be predictors of physical activity improvement for usual care participants.</p> <p>Conclusion</p> <p>This is the first study to examine differences in predictors of physical activity improvement between intervention group and control group participants enrolled in a physical activity intervention trial. While further empirical research is necessary to confirm findings, results suggest that participants with certain socio-demographic characteristics may respond favourably to minimal intensity interventions akin to the treatment delivered to participants in a usual care group. In future physical activity intervention trials, it may be possible to screen participants for baseline characteristics in order to target minimal-intensity interventions to those most likely to benefit. (Australian Clinical Trials Registry, <url>http://www.anzctr.org.au/default.aspx</url>, ACTRN012607000195459)</p

    Rural waste generation: a geographical survey at local scale

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    "The paper examines the per capita waste generation rates from from rural areas of NeamČ› County (Romania) using thematic cartography. Geographical approach of this issue is difficult because the lack of a geostatistic database at commune scale. Spatial analysis of waste indicators reveals several disparities between localities. Comparability of data between communes located in various geographical conditions must be carrefully made according to local waste management systems. Several dysfunctionalities are outlined in order to compare these results, on the one hand, between localities and on the one hand, between recent years. Geographical analysis of waste generation rates is imperative for a proper monitoring of this sector. Data from 2009, 2010 and 2012 shows that rural waste management is in a full process of change towards a more organized, stable and efficient system." (author's abstract

    Challenges to adaptation: a fundamental concept for the shared socio-economic pathways and beyond

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    The framework for the new scenarios being developed for climate research calls for the development of a set of Shared Socioeconomic Pathways (SSPs), which are meant to differ in terms of their challenges to mitigation and challenges to adaptation. In order for the scenario process to fulfill its goals, the research and policy communities need to develop a shared understanding of these concepts. This paper focuses on challenges to adaptation. We begin by situating this new concept in the context of the rich literatures related to inter alia adaptation, vulnerability, and resilience. We argue that a proper characterization of challenges to adaptation requires a rich, exploration of the concept, which goes beyond mere description. This has a number of implications for the operationalization of the concept in the basic and extended versions of the SSPs. First, the elements comprising challenges to adaptation must include a wide range of socioeconomic and even some (non-climatic) biophysical factors. Second, careful consideration must be given to differences in these factors across scales, as well as cross-scale interactions. Third, any representation of the concept will require both quantitative and qualitative elements. The scenario framework offers the opportunity for the SSPs and full scenarios to be of greater value than has been the case in past exercises to both Integrated Assessment Modeling (IAM) and Impacts,Adaptation, and Vulnerability (IAV) researchers, but this will require a renegotiation of the traditional, primarily unidirectional relationship between the two communities

    Living Well with Diabetes: a randomized controlled trial of a telephone-delivered intervention for maintenance of weight loss, physical activity and glycaemic control in adults with type 2 diabetes

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    Background By 2025, it is estimated that approximately 1.8 million Australian adults (approximately 8.4% of the adult population) will have diabetes, with the majority having type 2 diabetes. Weight management via improved physical activity and diet is the cornerstone of type 2 diabetes management. However, the majority of weight loss trials in diabetes have evaluated short-term, intensive clinic-based interventions that, while producing short-term outcomes, have failed to address issues of maintenance and broad population reach. Telephone-delivered interventions have the potential to address these gaps. Methods/Design Using a two-arm randomised controlled design, this study will evaluate an 18-month, telephone-delivered, behavioural weight loss intervention focussing on physical activity, diet and behavioural therapy, versus usual care, with follow-up at 24 months. Three-hundred adult participants, aged 20-75 years, with type 2 diabetes, will be recruited from 10 general practices via electronic medical records search. The Social-Cognitive Theory driven intervention involves a six-month intensive phase (4 weekly calls and 11 fortnightly calls) and a 12-month maintenance phase (one call per month). Primary outcomes, assessed at 6, 18 and 24 months, are: weight loss, physical activity, and glycaemic control (HbA1c), with weight loss and physical activity also measured at 12 months. Incremental cost-effectiveness will also be examined. Study recruitment began in February 2009, with final data collection expected by February 2013. Discussion This is the first study to evaluate the telephone as the primary method of delivering a behavioural weight loss intervention in type 2 diabetes. The evaluation of maintenance outcomes (6 months following the end of intervention), the use of accelerometers to objectively measure physical activity, and the inclusion of a cost-effectiveness analysis will advance the science of broad reach approaches to weight control and health behaviour change, and will build the evidence base needed to advocate for the translation of this work into population health practice

    Factors associated with patients self-reported adherence to prescribed physical activity in routine primary health care

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    <p>Abstract</p> <p>Background</p> <p>Written prescriptions of physical activity have increased in popularity. Such schemes have mostly been evaluated in terms of efficacy in clinical trials. This study reports on a physical activity prescription referral scheme implemented in routine primary health care (PHC) in Sweden. The aim of this study was to evaluate patients' self-reported adherence to physical activity prescriptions at 3 and 12 months and to analyse different characteristics associated with adherence to these prescriptions.</p> <p>Methods</p> <p>Prospective prescription data were obtained for the general population in 37 of 42 PHC centres in Östergötland County, during 2004. The study population consisted of 3300.</p> <p>Results</p> <p>The average adherence rate to the prescribed activity was 56% at 3 months and 50% at 12 months. In the multiple logistic regression models, higher adherence was associated with higher activity level at baseline and with prescriptions including home-based activities.</p> <p>Conclusions</p> <p>Prescription from ordinary PHC staff yielded adherence in half of the patients in this PAR scheme follow-up.</p

    Physical activity referrals in Swedish primary health care – prescriber and patient characteristics, reasons for prescriptions, and prescribed activities

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    <p>Abstract</p> <p>Background</p> <p>Over the past decade, practitioners in primary health care (PHC) settings in many countries have issued written prescriptions to patients to promote increased physical activity or exercise. The aim of this study is to describe and analyse a comprehensive physical activity referral (PAR) scheme implemented in a routine PHC setting in Östergötland County. The study examines characteristics of the PARs recipients and referral practitioners, identifies reasons why practitioners opted to use PARs with their clients, and discusses prescribed activities and prescriptions in relation to PHC registries.</p> <p>Methods</p> <p>Prospective prescription data were obtained for 90% of the primary health care centres in Östergötland County, Sweden, in 2004 and 2005. The study population consisted of patients who were issued PARs after they were deemed likely to benefit from increased physical activity, as assessed by PHC staff.</p> <p>Results</p> <p>During the two-year period, a total of 6,300 patients received PARs. Two-thirds of the patients were female and half of the patients were 45–64 years. Half of the patients (50.8%) who received PARs were recommended a home-based activity, such as walking. One third (33%) of the patients issued PARs were totally inactive, reporting no days of physical activity that lasted for 30 minutes, and 29% stated that they reached this level 1–2 days per week.</p> <p>The number of PARs prescribed per year in relation to the number of unique individuals that visited primary health care during one year was 1.4% in 2004 and 1.2% in 2005. Two-thirds of the combined prescriptions were issued by physicians (38%) and nurses (31%). Physiotherapists and behavioural scientists issued the highest relative number of prescriptions. The most common reasons for issuing PARs were musculoskeletal disorders (39.1%) and overweight (35.4%), followed by high blood pressure (23.3%) and diabetes (23.2%).</p> <p>Conclusion</p> <p>Östergötland County's PAR scheme reached a relatively high proportion of physically inactive people visiting local PHC centres for other health reasons. PAR-related statistics, including PAR-rates by individual PHC centres and PAR- rates per health professional category, show differences in prescribing activities, both by patient categories, and by prescribing professionals.</p

    The Origins of Novel Protein Interactions during Animal Opsin Evolution

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    Background. Biologists are gaining an increased understanding of the genetic bases of phenotypic change during evolution. Nevertheless, the origins of phenotypes mediated by novel protein-protein interactions remain largely undocumented. Methodology/Principle Findings. Here we analyze the evolution of opsin visual pigment proteins from the genomes of early branching animals, including a new class of opsins from Cnidaria. We combine these data with existing knowledge of the molecular basis of opsin function in a rigorous phylogenetic framework. We identify adaptive amino acid substitutions in duplicated opsin genes that correlate with a diversification of physiological pathways mediated by different protein-protein interactions. Conclusions/Significance. This study documents how gene duplication events early in the history of animals followed by adaptive structural mutations increased organismal complexity by adding novel protein-protein interactions that underlie different physiological pathways. These pathways are central to vision and other photo-reactive phenotypes in most extant animals. Similar evolutionary processes may have been a work in generating other metazoan sensory systems and other physiological processes mediated by signal transduction
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