993 resultados para 003
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The prevalence of osteoporosis is expected to increase with the ageing of the world’s population. This article reviews the epidemiology, risk factors and health burden of osteoporosis. In the Global Burden of Disease (GBD) Study 2005, osteoporosis is studied as a risk factor for fracture by considering the bone-mineral-density (BMD) measurement as the continuous exposure variable. We have performed a systematic review seeking population-based studies with BMD data measured by dual-X-ray absorptiometry (DXA). The femoral neck was selected as the unique location and all values were converted into Hologic® to enable inclusion of worldwide data for analysis. Provisional results on mean BMD values for different world regions are shown in age breakdowns for males and females 50 years or over, as well as mean T-scores using the young, white, female reference of National Health and Nutrition Examination Survey (NHANES) III. Results show remarkable geographical differences and a time trend towards improvement of the BMD values in Asian and European populations.
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E. coli does chemotaxis by performing a biased random walk composed of alternating periods of swimming (runs) and reorientations (tumbles). Tumbles are typically modelled as complete directional randomisations but it is known that in wild type E. coli, successive run directions are actually weakly correlated, with a mean directional difference of ∼63°. We recently presented a model of the evolution of chemotactic swimming strategies in bacteria which is able to quantitatively reproduce the emergence of this correlation. The agreement between model and experiments suggests that directional persistence may serve some function, a hypothesis supported by the results of an earlier model. Here we investigate the effect of persistence on chemotactic efficiency, using a spatial Monte Carlo model of bacterial swimming in a gradient, combined with simulations of natural selection based on chemotactic efficiency. A direct search of the parameter space reveals two attractant gradient regimes, (a) a low-gradient regime, in which efficiency is unaffected by directional persistence and (b) a high-gradient regime, in which persistence can improve chemotactic efficiency. The value of the persistence parameter that maximises this effect corresponds very closely with the value observed experimentally. This result is matched by independent simulations of the evolution of directional memory in a population of model bacteria, which also predict the emergence of persistence in high-gradient conditions. The relationship between optimality and persistence in different environments may reflect a universal property of random-walk foraging algorithms, which must strike a compromise between two competing aims: exploration and exploitation. We also present a new graphical way to generally illustrate the evolution of a particular trait in a population, in terms of variations in an evolvable parameter.
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This paper provides an outline of the work undertaken by nurses who participated in the relief effort as members of Australian medical teams during the Sumatra-Andaman earthquake and tsunami response. This profile is contrasted with the information provided by nurses who registered their interest in volunteering to help via the Australian Tsunami Hotline. The paper provides an overview of the skills and background of the nurses who provided information to the hotline and describes the range and extent of experience among this cohort of potential volunteers. This data is compared to nursing workforce data and internal rates of volunteering in Australia. The paper concludes that further research is necessary to examine the motivations of and disincentives for nurses to volunteer for overseas (disaster) work and, to develop an improved understanding within the discipline of the skills and experience required of volunteer responders. Further, it is argued that the development of standards for the collection of disaster health volunteer data would assist future responses and provide better tools for developing an improved understanding of disaster volunteering.
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We report that tumor cells devoid of their mitochondrial genome (mtDNA) show delayed tumor growth and that tumor formation is associated with acquisition of mtDNA from host cells. This leads to partial recovery of mitochondrial function in cells derived from primary tumors grown from cells without mtDNA and a shorter lag in tumor growth. Cell lines from circulating tumor cells showed further recovery of mitochondrial respiration and an intermediate lag to tumor growth, while cells from lung metastases exhibited full restoration of respiratory function and no lag in tumor growth. Stepwise assembly of mitochondrial respiratory supercomplexes was correlated with acquisition of respiratory function. Our findings indicate horizontal transfer of mtDNA from host cells in the tumor microenvironment to tumor cells with compromised respiratory function to re-establish respiration and tumor-initiating efficacy. These results suggest a novel pathophysiological process for overcoming mtDNA damage and support the notion of high plasticity of malignant cells.
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Differential response has long been utilized by statutory child protection systems in Australia. This article describes the advent and history of Victoria's differential response system, with a particular focus on the Child FIRST and IFS programme. This program entails a partnership arrangement between the Department of Human Services child protection services and community-based, not-for-profit agencies to provide a diverse range of early intervention and prevention services. The findings of a recent external service system evaluation, a judicial inquiry, and the large-scale Child and Family Services Outcomes Survey of parents/carers perspectives of their service experiences are used to critically examine the effectiveness of this differential response approach. Service-user perspectives of the health and wellbeing of children and families are identified, as well as the recognized implementation issues posing significant challenges for the goal of an integrated partnership system. The need for ongoing reform agendas is highlighted along with the policy, program and structural tensions that exist in differential response systems, which are reliant upon partnerships and shared responsibilities for protecting children and assisting vulnerable families. Suggestions are made for utilizing robust research and evaluation that gives voice to service users and promotes their rights and interests.
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Intelligent Transport Systems (ITS) have the potential to substantially reduce the number of crashes caused by human errors at railway levels crossings. Such systems, however, will only exert an influence on driving behaviour if they are accepted by the driver. This study aimed at assessing driver acceptance of different ITS interventions designed to enhance driver behaviour at railway crossings. Fifty eight participants, divided into three groups, took part in a driving simulator study in which three ITS devices were tested: an in-vehicle visual ITS, an in-vehicle audio ITS, and an on-road valet system. Driver acceptance of each ITS intervention was assessed in a questionnaire guided by the Technology Acceptance Model and the Theory of Planned Behaviour. Overall, results indicated that the strongest intentions to use the ITS devices belonged to participants exposed to the road-based valet system at passive crossings. The utility of both models in explaining drivers’ intention to use the systems is discussed, with results showing greater support for the Theory of Planned Behaviour. Directions for future studies, along with strategies that target attitudes and subjective norms to increase drivers’ behavioural intentions, are also discussed.
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Background Food neophobia, the rejection of unknown or novel foods, may result in poor dietary patterns. This study investigates the cross-sectional relationship between neophobia in children aged 24 months and variety of fruit and vegetable consumption, intake of discretionary foods and weight. Methods Secondary analysis of data from 330 parents of children enrolled in the NOURISH RCT (control group only) and SAIDI studies was performed using data collected at child age 24 months. Neophobia was measured at 24 months using the Child Food Neophobia Scale (CFNS). The cross-sectional associations between total CFNS score and fruit and vegetable variety, discretionary food intake and BMI (Body Mass Index) Z-score were examined via multiple regression models; adjusting for significant covariates. Results At 24 months, more neophobic children were found to have lower variety of fruits (β=-0.16, p=0.003) and vegetables (β=-0.29, p<0.001) but have a greater proportion of daily energy from discretionary foods (β=0.11, p=0.04). There was no significant association between BMI Z-score and CFNS score. Conclusions Neophobia is associated with poorer dietary quality. Results highlight the need for interventions to (1) begin early to expose children to a wide variety of nutritious foods before neophobia peaks and (2) enable health professionals to educate parents on strategies to overcome neophobia.
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Parental controlling feeding practices have been directly associated with maladaptive child eating behaviours, such as Eating in the Absence of Hunger (EAH). The aim of this study was to examine EAH in very young children (3-4 years old) and to investigate the association between maternal controlling feeding practices and energy intake from a standardised selection of snacks consumed ‘in the absence of hunger’. Thirty-seven mother-child dyads enrolled in the NOURISH RCT participated in a modified EAH protocol conducted in the child’s home. All children displayed EAH, despite 80% reporting to be full or very full following completion of lunch 15 minutes earlier. The relationship between maternal and child covariates and controlling feeding practices and EAH were examined using non-parametric tests, and were stratified by child gender. For boys only, pressure to eat was positively associated with EAH. Neither restriction nor monitoring practices were associated with EAH in either boys or girls. Overall, the present findings suggest gender differences in the relationship between maternal feeding practices and children’s eating behaviours emerge early and should be considered in future research and intervention design.
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Background Definitive cisplatin-based is increasingly delivered as the treatment of choice for patients with head and neck cancer. Sensorineural hearing loss is a significant long term side effect of cisplatin-based chemoradiation and is associated with potential major quality of life issues for patients. Purpose The purpose of this manuscript was to review the mechanism behind sensorineural hearing loss in patients treated with cisplatin-based chemoradiation, including incidence, the contributions of radiotherapy and cisplatin to sensorineural hearing loss and the impact of the toxicity on patient quality of life. Methods Database searches were conducted through PubMed (National Centre for Biotechnology Information) and OvidSP Medline via the Queensland University of Technology Library website. General article searches were conducted through the online search engine Google Scholar. Articles were excluded if the full-text was unavailable, they were not in English or if they were published prior to 1990. Keywords included hearing loss, ototoxicity, cancer, quality of life, cisplatin and radiotherapy. Results/Discussion The total number of journal articles accessed was 290. Due to exclusion criteria, 129 articles were deemed appropriated for review. Findings indicated that sensorineural hearing loss is a significant, long term complication for patients treated with cisplatin-based chemoradiation. Current literature recognises the ototoxic effects of cisplatin and cranial irradiation as separate entities, however the impact of combined modality therapy on sensorineural hearing loss is seldom reported. Multiple risk factors for hearing loss are described, however there are contradictory opinions on incidence and severity and the exact radiation dose threshold responsible for inducing hearing loss in patients receiving combined modality therapy. Sensorineural hearing loss creates a subset of complexities for patients with head and neck cancer and that these patients face significant quality of life impairment. Conclusion The literature review identified that sensorineural hearing loss is a major quality of life issue for patients treated with cisplatin-based chemoradiation for head and neck cancer. Further investigation evaluating the contribution of cisplatin-based chemoradiation to sensorineural hearing loss and the subsequent effect on patient quality of life is warranted.
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The surfaces of natural beidellite were modified with cationic surfactant octadecyl trimethylammonium bromide at different concentrations. The organo-beidellite adsorbent materials were then used for the removal of atrazine with the goal of investigating the mechanism for the adsorption of organic triazine herbicide from contaminated water. Changes on the surfaces and structure of beidellite were characterised by X-ray diffraction (XRD), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and BET surface analysis. Kinetics of the adsorption studies were also carried out which show that the adsorption capacity of the organoclays increases with increasing surfactant concentration up until 1.0 CEC surfactant loading, after which the adsorption capacity greatly decreases. TG analysis reveals that although the 2.0 CEC sample has the greatest percentage of surfactant by mass, most of it is present on external sites. The 0.5 CEC sample has the highest proportion of surfactant exchanged into the internal active sites and the 1.0 CEC sample accounts for the highest adsorption capacity. The goodness of fit of the pseudo-second order kinetic confirms that chemical adsorption, rather than physical adsorption, controls the adsorption rate of atrazine.
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Objectives To determine the frequency and types of stressful events experienced by urban Aboriginal and Torres Strait Islander children, and to explore the relationship between these experiences and the children’s physical health and parental concerns about their behaviour and learning ability. Design, setting and participants Cross-sectional study of Aboriginal and Torres Strait Islander children aged ≤ 14 years presenting to an urban Indigenous primary health care service in Brisbane for annual child health checks between March 2007 and March 2010. Main outcome measures Parental or carer report of stressful events ever occurring in the family that may have affected the child. Results Of 344 participating children, 175 (51%) had experienced at least one stressful event. Reported events included the death of a family member or close friend (40; 23%), parental divorce or separation (28; 16%), witness to violence or abuse (20; 11%), or incarceration of a family member (7; 4%). These children were more likely to have parents or carers concerned about their behaviour (P < 0.001) and to have a history of ear (P < 0.001) or skin (P = 0.003) infections. Conclusions Children who had experienced stressful events had poorer physical health and more parental concern about behavioural issues than those who had not. Parental disclosure in the primary health care setting of stressful events that have affected the child necessitates appropriate medical, psychological or social interventions to ameliorate both the immediate and potential lifelong negative impact. However, treating the impact of stressful events is insufficient without dealing with the broader political and societal issues that result in a clustering of stressful events in the Aboriginal and Torres Strait Islander population.
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This paper develops a dynamic model for cost-effective selection of sites for restoring biodiversity when habitat quality develops over time and is uncertain. A safety-first decision criterion is used for ensuring a minimum level of habitats, and this is formulated in a chance-constrained programming framework. The theoretical results show; (i) inclusion of quality growth reduces overall cost for achieving a future biodiversity target from relatively early establishment of habitats, but (ii) consideration of uncertainty in growth increases total cost and delays establishment, and (iii) cost-effective trading of habitat requires exchange rate between sites that varies over time. An empirical application to the red listed umbrella species - white-backed woodpecker - shows that the total cost of achieving habitat targets specified in the Swedish recovery plan is doubled if the target is to be achieved with high reliability, and that equilibrating price on a habitat trading market differs considerably between different quality growth combinations. © 2013 Elsevier GmbH.
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The research field of urban computing – defined as “the integration of computing, sensing, and actuation technologies into everyday urban settings and lifestyles” – considers the design and use of ubiquitous computing technology in public and shared urban environments. Its impact on cities, buildings, and spaces evokes innumerable kinds of change. Embedded into our everyday lived environments, urban computing technologies have the potential to alter the meaning of physical space, and affect the activities performed in those spaces. This paper starts a multi-themed discussion of various aspects that make up the, at times, messy and certainly transdisciplinary field of urban computing and urban informatics.
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Purpose To investigate the frequency of convergence and accommodation anomalies in an optometric clinical setting in Mashhad, Iran, and to determine tests with highest accuracy in diagnosing these anomalies. Methods From 261 patients who came to the optometric clinics of Mashhad University of Medical Sciences during a month, 83 of them were included in the study based on the inclusion criteria. Near point of convergence (NPC), near and distance heterophoria, monocular and binocular accommodative facility (MAF and BAF, respectively), lag of accommodation, positive and negative fusional vergences (PFV and NFV, respectively), AC/A ratio, relative accommodation, and amplitude of accommodation (AA) were measured to diagnose the convergence and accommodation anomalies. The results were also compared between symptomatic and asymptomatic patients. The accuracy of these tests was explored using sensitivity (S), specificity (Sp), and positive and negative likelihood ratios (LR+, LR−). Results Mean age of the patients was 21.3 ± 3.5 years and 14.5% of them had specific binocular and accommodative symptoms. Convergence and accommodative anomalies were found in 19.3% of the patients; accommodative excess (4.8%) and convergence insufficiency (3.6%) were the most common accommodative and convergence disorders, respectively. Symptomatic patients showed lower values for BAF (p = .003), MAF (p = .001), as well as AA (p = .001) compared with asymptomatic patients. Moreover, BAF (S = 75%, Sp = 62%) and MAF (S = 62%, Sp = 89%) were the most accurate tests for detecting accommodative and convergence disorders in terms of both sensitivity and specificity. Conclusions Convergence and accommodative anomalies are the most common binocular disorders in optometric patients. Including tests of monocular and binocular accommodative facility in routine eye examinations as accurate tests to diagnose these anomalies requires further investigation.
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Purpose The aim of this study was to explore how first-line nurse managers constructed the meaning of resilience and its relationship to work-life balance for nurses in Korea. Methods Participants were 20 first-line nurse managers working in six university hospitals. Data were collected through in-depth interviews from December 2011 to August 2012, and analyzed using Strauss and Corbin's grounded theory method. Results Analysis revealed that participants perceived work-life balance and resilience to be shaped by dynamic, reflective processes. The features consisting resilience included "positive thinking", "flexibility", "assuming responsibility", and "separating work and life". This perception of resilience has the potential to facilitate a shift in focus from negative to positive experiences, from rigidity to flexibility, from task-centered to person-centered thinking, and from the organization to life. Conclusions Recognizing the importance of work-life balance in producing and sustaining resilience in first-line nurse managers could increase retention in the Korean nursing workforce.