1,684 research outputs found
Evaluation of the performance of different atmospheric chemical transport models and inter-comparison of nitrogen and sulphur deposition estimates for the UK
An evaluation has been made of a number of contrasting atmospheric chemical transport models, of varying complexity, applied to estimate sulphur and nitrogen deposition in the UK. The models were evaluated by comparison with annually averaged measurements of gas, aerosol and precipitation concentrations from the national monitoring networks. The models were evaluated in relation to performance criteria. They were generally able to satisfy a criterion of ‘fitness for purpose’ that at least 50% of modelled concentrations should be within a factor of two of measured values. The second criterion, that the magnitude of the normalised mean bias should be less than 20%, was not always satisfied. Considering known uncertainties in measurement techniques, this criterion may be too strict. Overall, simpler models were able to give a good representation of measured gas concentrations whilst the use of dynamic meteorology, and complex photo-chemical reactions resulted in a generally better representation of measured aerosol and precipitation concentrations by more complex models.
The models were compared graphically by plotting maps and cross-country transects of wet and dry deposition as well as calculating budgets of total wet and dry deposition to the UK for sulphur, oxidised nitrogen and reduced nitrogen. The total deposition to the UK varied by ±22–36% amongst the different models depending on the deposition component. At a local scale estimates of both dry and wet deposition for individual 5 km × 5 km model grid squares were found to vary between the different models by up to a factor of 4.This work was funded by the Department for the Environment, Food and Rural Affairs. Additional support was provided by the Joint Environmental Program, the Natural Environment Research Council and the Environment Agency.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.atmosenv.2015.08.00
Evidence synthesis as the key to more coherent and efficient research
<p>Abstract</p> <p>Background</p> <p>Systematic review and meta-analysis currently underpin much of evidence-based medicine. Such methodologies bring order to <it>previous </it>research, but <it>future </it>research planning remains relatively incoherent and inefficient.</p> <p>Methods</p> <p>To outline a framework for evaluation of health interventions, aimed at increasing coherence and efficiency through i) making better use of information contained within the existing evidence-base when designing future studies; and ii) maximising the information available and thus potentially reducing the need for future studies.</p> <p>Results</p> <p>The framework presented insists that an up-to-date meta-analysis of existing randomised controlled trials (RCTs) should always be considered before future trials are conducted. Such a meta-analysis should inform critical design issues such as sample size determination. The contexts in which the use of individual patient data meta-analysis and mixed treatment comparisons modelling may be beneficial before further RCTs are conducted are considered. Consideration should also be given to how any newly planned RCTs would contribute to the totality of evidence through its incorporation into an updated meta-analysis. We illustrate how new RCTs can have very low power to change inferences of an existing meta-analysis, particularly when between study heterogeneity is taken into consideration.</p> <p>Conclusion</p> <p>While the collation of existing evidence as the basis for clinical practice is now routine, a more coherent and efficient approach to planning future RCTs to strengthen the evidence base needs to be developed. The framework presented is a proposal for how this situation can be improved.</p
The Impact of HAART on the Respiratory Complications of HIV Infection: Longitudinal Trends in the MACS and WIHS Cohorts
Objective: To review the incidence of respiratory conditions and their effect on mortality in HIV-infected and uninfected individuals prior to and during the era of highly active antiretroviral therapy (HAART). Design: Two large observational cohorts of HIV-infected and HIV-uninfected men (Multicenter AIDS Cohort Study [MACS]) and women (Women's Interagency HIV Study [WIHS]), followed since 1984 and 1994, respectively. Methods: Adjusted odds or hazards ratios for incident respiratory infections or non-infectious respiratory diagnoses, respectively, in HIV-infected compared to HIV-uninfected individuals in both the pre-HAART (MACS only) and HAART eras; and adjusted Cox proportional hazard ratios for mortality in HIV-infected persons with lung disease during the HAART era. Results: Compared to HIV-uninfected participants, HIV-infected individuals had more incident respiratory infections both pre-HAART (MACS, odds ratio [adjusted-OR], 2.4; 95% confidence interval [CI], 2.2-2.7; p<0.001) and after HAART availability (MACS, adjusted-OR, 1.5; 95%CI 1.3-1.7; p<0.001; WIHS adjusted-OR, 2.2; 95%CI 1.8-2.7; p<0.001). Chronic obstructive pulmonary disease was more common in MACS HIV-infected vs. HIV-uninfected participants pre-HAART (hazard ratio [adjusted-HR] 2.9; 95%CI, 1.02-8.4; p = 0.046). After HAART availability, non-infectious lung diseases were not significantly more common in HIV-infected participants in either MACS or WIHS participants. HIV-infected participants in the HAART era with respiratory infections had an increased risk of death compared to those without infections (MACS adjusted-HR, 1.5; 95%CI, 1.3-1.7; p<0.001; WIHS adjusted-HR, 1.9; 95%CI, 1.5-2.4; p<0.001). Conclusion: HIV infection remained a significant risk for infectious respiratory diseases after the introduction of HAART, and infectious respiratory diseases were associated with an increased risk of mortality. © 2013 Gingo et al
Frequency of human immunodeficiency virus (HIV) testing in urban vs. rural areas of the United States: Results from a nationally-representative sample
<p>Abstract</p> <p>Background</p> <p>Studies in the United States show that rural persons with HIV are more likely than their urban counterparts to be diagnosed at a late stage of infection, suggesting missed opportunities for HIV testing in rural areas. To inform discussion of HIV testing policies in rural areas, we generated nationally representative, population-based estimates of HIV testing frequencies in urban vs. rural areas of the United States.</p> <p>Methods</p> <p>Secondary analysis of 2005 and 2009 Behavioral Risk Factor Surveillance System (BRFSS) data. Dependent variables were self-reported lifetime and past-year HIV testing. Urban vs. rural residence was determined using the metropolitan area framework and Urban Influence Codes and was categorized as 1) metropolitan, center city (the most urban); 2) metropolitan, other; 3) non-metropolitan, adjacent to metropolitan; 4) non-metropolitan, micropolitan; and 4) remote, non-metropolitan (the most rural).</p> <p>Results</p> <p>The 2005 sample included 257,895 respondents. Lifetime HIV testing frequencies ranged from 43.6% among persons residing in the most urban areas to 32.2% among persons in the most rural areas (P < 0.001). Past-year testing frequencies ranged from 13.5% to 7.3% in these groups (P < 0.001). After adjusting for demographics (age, sex, race/ethnicity, and region of residence) and self-reported HIV risk factors, persons in the most remote rural areas were substantially less likely than persons in the most urban areas to report HIV testing in the past year (odds ratio 0.65, 95% CI 0.57-0.75). Testing rates in urban and rural areas did not change substantively following the 2006 Centers for Disease Control and Prevention recommendation for routine, population-based HIV testing in healthcare settings. In metropolitan (urban) areas, 11.5% (95% CI 11.2-11.8) reported past-year HIV testing in 2005 vs. 11.4% (95% CI 11.1%-11.7%) in 2009 (P = 0.93). In non-metropolitan areas, 8.7% (95% CI 8.2%-9.2%) were tested in 2005 vs. 7.7% (95% CI 7.2%-8.2%) in 2009 (P = 0.03).</p> <p>Conclusions</p> <p>Rural persons are less likely than urban to report prior HIV testing, which may contribute to later HIV diagnosis in rural areas. There is need to consider strategies to increase HIV testing in rural areas.</p
Global patterns of the leaf economics spectrum in wetlands
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In Vivo MR Imaging of Magnetically Labeled Mesenchymal Stem Cells in a Rat Model of Renal Ischemia
Objective: This study was designed to evaluate in vivo MR imaging for the depiction of intraarterially injected superparamagnetic iron oxide (SPIO)-labeled mesenchymal stem cells (MSCs) in an experimental rat model of renal ischemia. Materials and Methods: Left renal ischemia was induced in 12 male Sprague-Dawley rats by use of the catheter lodging method. In vivo MR signal intensity variations depicted on T2*-weighted sequences were evaluated in both the left and right kidneys prior to injection (n = 2), two hours (n = 4), 15 hours (n = 2), 30 hours (n = 2) and 72 hours (n = 2) after injection of SPIO-labeled MSCs in both kidneys. Signal intensity variations were correlated with the number of Prussian blue stain-positive cells as visualized in histological specimens. Results: In an in vivo study, it was determined that there was a significant difference in signal intensity variation for both the left and right cortex (40.8 +/- 4.12 and 26.4 +/- 7.92, respectively) and for both the left and right medulla (23.2 +/- 3.32 and 15.2 +/- 3.31, respectively) until two hours after injection (p < 0.05). In addition, signal intensity variation in the left renal cortex was well correlated with the number of Prussian blue stain-positive cells per high power field (r = 0.98, p < 0.05). Conclusion: Intraarterial injected SPIO-labeled MSCs in an experimental rat model of renal ischemia can be detected with the use of in vivo MR imaging immediately after injection.This study was partly supported by a grant from the
Seoul Research and Business Development Program 10548
and by a grant (A062260) from the Innovative Research
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Parents’ perspectives on their children’s music therapy: A synthesis of qualitative literature
There is no existing qualitative synthesis of the music therapy literature on parents’ perspectives on their children’s music therapy. This study seeks to fill this gap, motivated by the first author’s experiences as a clinician/researcher. A systematic search of health databases, hand searches of key journals and searches of doctoral theses were undertaken to identify relevant studies. Thirteen studies which met inclusion criteria, including a total of 102 participants, were identified. Relevant data were extracted from these studies for comparison and analysis, with quality of studies assessed using the CASP appraisal tool. Findings were analysed following procedures of thematic synthesis. Six descriptive themes were grouped into three analytic themes: Parents perceived positive impacts of music therapy on their children; parents experienced music therapy as a nurturing environment for themselves and their children; and some parents experienced challenges to their engagement with music therapy. Most studies (12/13) explored parents’ perceptions of music therapy where they were included in sessions. The findings identify positive perceptions of family-centred models of music therapy for children and parents. Parents’ perceptions of children were altered positively through experiencing them in new ways in music therapy. Parents also perceived positive outcomes for their children. These findings identify an emphasis in the qualitative literature on parents’ perceptions on research into music therapy which includes parents in sessions. Only one study explored perceptions of a model where parents were not present during their child’s sessions. More research is needed into parents’ perceptions of music therapy where parents are not present during sessions. Further intervention studies into family-centred models of music therapy with children are also recommended
Diagnostic Benefit of Thyroglobulin Measurement in Fine-Needle Aspiration for Diagnosing Metastatic Cervical Lymph Nodes from Papillary Thyroid Cancer: Correlations with US Features
Objective: Our goals were to determine the added value of fine-needle aspiration biopsy (FNAB)-thyroglobulin (Tg) measurements over FNAB-cytology alone for diagnosing metastatic nodes, and to determine whether the ultrasound features of lymph nodes can be used to identify lymph nodes that may benefit from FNAB-Tg measurement in patients with papillary thyroid cancer. Materials and Methods: We retrospectively evaluated 76 surgically proven cervical lymph nodes. Twenty-nine patients were awaiting surgery and 18 patients had undergone thyroid surgery for papillary thyroid cancer. Ultrasound-guided FNAB and Tg measurements were performed and the ultrasound features were evaluated. Results: The accuracies, sensitivities, and specificities of FNAB-cytology, FNAB-Tg, and combined FNAB-Tg/cytology were 90%, 80%, and 100%; 92%, 95%, and 90%; and 93%, 96%, and 90%, respectively. The diagnostic sensitivity of FNAB-Tg for metastatic nodes was significantly higher than that of FNAB-cytology (p = 0.011). Furthermore, combined FNAB-Tg/cytology significantly increased sensitivity (p = 0.002) and accuracy (p = 0.03) as compared with FNAB-cytology. Conclusion: Combined FNAB-Tg/cytology is significantly more sensitive and accurate at detecting metastatic nodes than FNAB-cytology alone. FNAB-Tg was better at diagnosing metastases in small lymph nodes
Developmental programming: State-of-the-science and future directions-Summary from a Pennington Biomedical symposium.
OBJECTIVE: On December 8-9, 2014, the Pennington Biomedical Research Center convened a scientific symposium to review the state-of-the-science and future directions for the study of developmental programming of obesity and chronic disease. The objectives of the symposium were to discuss: (i) past and current scientific advances in animal models, population-based cohort studies, and human clinical trials, (ii) the state-of-the-science of epigenetic-based research, and (iii) considerations for future studies. RESULTS: This symposium provided a comprehensive assessment of the state of the scientific field and identified research gaps and opportunities for future research in order to understand the mechanisms contributing to the developmental programming of health and disease. CONCLUSIONS: Identifying the mechanisms which cause or contribute to developmental programming of future generations will be invaluable to the scientific and medical community. The ability to intervene during critical periods of prenatal and early postnatal life to promote lifelong health is the ultimate goal. Considerations for future research including the use of animal models, the study design in human cohorts with considerations about the timing of the intrauterine exposure, and the resulting tissue-specific epigenetic signature were extensively discussed and are presented in this meeting summary.The symposium was funded by NORC Center Grant P30DK072476 from the NIDDK. LAG is supported by T32DK064584 from the NIDDK. Work in MS Laboratory was supported by MOP‐42411 from the Canadian Institute of Health Research. Work in JAM Laboratory was supported by the Center for Nutrition Research at the University of Navarra in Pamplona, Spain. RAW is supported by a grant from the U.S. Department of Agriculture (USDA) [CRIS 3092‐5‐001‐059]. Work in BTH Laboratory was supported by the National Institutes of Health (R01AG042190) and the European Union's Seventh Framework Program IDEAL (FP7/2007‐2011; grant agreement No. 259679). Work in CL Laboratory was funded by The Swedish Research Council and The Novo Nordisk Foundation. SEO is a member of the University of Cambridge MRC Metabolic Diseases Unit. MFH is the recipient of an American Diabetes Association (ADA) Pathways To Stop Diabetes Award. Work in ER and LMR Laboratories was partially funded by a NORC grant titled “Nutritional Programming: Environmental and Molecular Interactions” to ER (P30DK072476)
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