1,662 research outputs found

    Integration of organic poultry in whole farm systems: manure nutrient budgets

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    This report was presented at the UK Organic Research 2002 Conference. The aim of this project was to examine how rotations incorporating organic poultry use the cycling of nutrients between soil, crops and birds. Poultry studies have measured nutrient values of manure in slow growing meat birds at about day 81 when fed typical broiler rations versus “Label Rouge” rations. Nutrient (N, P, K) balances were constructed to assess the viability of integrating poultry production within a theoretical organic rotation. The readilyplant- available nitrogen in manure from Ross 308 birds fed either presumed non-limiting rations or Label Rouge rations was within the range reported for intensive broilers. For ISA 657 birds, the manure readily-plant-available nitrogen was similar to the mean value reported for broilers, when fed presumed non limiting rations, but towards the lower range when fed Label Rouge rations. As breed growth and feed intakes differ it is suggested that to optimise the utilisation of nutrients, the nutrient content of table bird manures should be checked prior to land application. The nutrient budgets were similar for N and P regardless of the length of rotation or form of poultry production. On average, there was a surplus of 85 kg/ha N over all the scenarios. There tended to be a deficit of K in all scenarios (average: 10 kg/ha)

    Three Essays on Economic Growth and Natural Resources

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    This dissertation is a collection of papers examining the relationship between resource intensity and economic growth in the Appalachian region of the United States. The first chapter develops a homogenous sample of counties within the Appalachian region and uses that sample to investigate how coal resources impact long-run per capita income growth. The Appalachian Regional Commission\u27s definition of the Appalachian region is the one used most often by researchers, politicians, and the popular press. The uncritical use of this definition of Appalachia raises issues of both selection bias and excess heterogeneity in regression analysis of Appalachian income and growth. The ARC was created as part of President Johnson\u27s war on poverty, and the geographical extent of its purview has been driven by politics and by the geography of poverty, neither of which is exogenous. It is well known that the use of endogenous variables to choose a sample creates bias and inconsistency in estimation of regression coefficients. To identify the counties that belong to the Appalachian region exogenously we use an algorithm based on three criteria: topography, contiguity, and prevalence of slavery in the 1860 census. We apply our sample to growth regressions using data from 1970 to 2008, addressing the question of the existence of a resource curse from coal extraction. For this model we find strong evidence of excess heterogeneity, but not bias.;In the second chapter, I extend the analysis by exploring different possible measures for coal resource abundance. I use both a geologic based measure of abundance and a flow based measure of dependence , and find evidence that coal abundance significantly reduces growth of per capita income over the long run with both measures. In addition, I use a wide variety of alternative measures of resource abundance suggested by the literature, all which indicate a negative systematic effect of resources on income growth. I account for the endogeneity of the each flow measure with instruments, and when I also account for the endogeneity of initial income, results indicate that a one standard deviation increase in the measure of resource intensity results in a 0.43 percentage point drop in average annual growth.;In the third chapter, I investigate several of the causes for the under-performance by many resource rich counties in the Appalachian region. I examine the effect of coal abundance on educational attainment, local (county) level education expenditure decisions, and local level taxation decisions. I find evidence that the educational attainment channel accounts for a significant portion of the negative effect of resource abundance. Coal resource abundance tends to reduce educational attainment, reducing human capital in a county, which in turn reduces per capita income growth over the long run. When attainment is measured by the share of the population that dropped out of high school, a one standard deviation increase in the measure of resource abundance reduces average annual growth by an estimated 0.125 percentage points. When educational attainment is measured instead by the share of the population that completed a college degree, average annual growth is reduced by an estimated 0.037 percentage points. I find no evidence that resource abundance affects the education expenditure allocation decisions of local county governments, nor do I find evidence that resource rich counties test to under tax their populations

    Stimulation of the tibial nerve: a protocol for a multicentred randomised controlled trial for urinary problems associated with Parkinson’s disease—STARTUP

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    Introduction Parkinson’s disease is the second most common chronic neurodegenerative condition with bladder dysfunction affecting up to 71%. Symptoms affect quality of life and include urgency, frequency, hesitancy, nocturia and incontinence. Addressing urinary dysfunction is one of the top 10 priority research areas identified by the James Lind Alliance and Parkinson’s UK. Objectives Conduct a randomised controlled trial (RCT) targeting people with Parkinson’s disease (PwP) who have self-reported problematic lower urinary tract symptoms, investigating the effectiveness of transcutaneous tibial nerve stimulation (TTNS) compared with sham TTNS. Implement a standardised training approach and package for the correct application of TTNS. Conduct a cost-effectiveness analysis of TTNS compared with sham TTNS. Methods and analysis An RCT of 6 weeks with twice weekly TTNS or sham TTNS. Participants will be recruited in 12 National Health Service neurology/movement disorder services, using a web-based randomisation system, and will be shown how to apply TTNS or sham TTNS. Participants will receive a weekly telephone call from the researchers during the intervention period. The trial has two coprimary outcome measures: International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form and the International Prostate Symptom Score. Secondary outcomes include a 3-day bladder diary, quality of life, acceptability and fidelity and health economic evaluation. Outcomes will be measured at 0, 6 and 12 weeks. A sample size of 208 randomised in equal numbers to the two arms will provide 90% power to detect a clinically important difference of 2.52 points on the Internatioanl Consultation on Incontinence Questionnaire - Short Form (ICIQ-SF) and of 3 points in the International Prostate Symptom Score total score at 12 weeks at 5% significance level, based on an SD of 4.7 in each arm and 20% attrition at 6 weeks. Analysis will be by intention to treat and pre defined in a statistical analysis plan Ethics and dissemination East of Scotland Research Ethics Service (EoSRES), 18/ES00042, obtained on 10 May 2018. The trial will allow us to determine effectiveness, safety, cost and acceptability of TTNS for bladder dysfunction in PWP. Results will be published in open access journals; lay reports will be posted to all participants and presented at conferences. Trial registration number ISRCTN12437878; Pre-results

    Variation in clinical presentation of childhood group A streptococcal pharyngitis in four countries

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    Funding Information: This study was supported by USAID. The Croatian and Latvian site was funded by the Department of Child and Adolescent Health and Development, World Health Organization, Geneva.We conducted a cross-sectional study from September 2001 to August 2003 during which children between 2 and 12 years of age presenting with complaint of sore throat were recruited from urban pediatric clinics in Brazil, Croatia, Egypt and Latvia. The objective of the study was to compare clinical signs and symptoms of children presenting to urban pediatric clinics with sore throat in and between countries and to identify common clinical criteria predicting group A beta hemolytic streptococcal (GAS) pharyngitis. Using a single standard protocol in all four sites, clinical data were recorded and throat swabs obtained for standard GAS culture in 2040 children. Signs and symptoms were tested for statistical association with GAS positive/negative pharyngitis, and were compared using X2 tests, ANOVA and Odds Ratios. Clinical signs of GAS pharyngitis in children presenting to clinics varied significantly between countries, and there were few signs or symptom that could statistically be associated with GAS pharyngitis in all four countries, though several were useful in two or three countries. Our results indicate that the clinical manifestations of pharyngitis in clinics may vary by region. It is therefore critical that clinical decision rules for management of pharyngitis should have local validation.publishersversionPeer reviewe

    The utility of rapid antigen detection testing for the diagnosis of streptococcal pharyngitis in low-resource settings

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    Funding Information: This study was supported by USAID. The Croatian and Latvian sites were funded by the Department of Child and Adolescent Health and Development, World Health Organization, Geneva. The authors alone are responsible for the views expressed in this publication and they do not necessarily represent the decisions or the stated policy of the World Health Organization. Thermo Biostar donated the STREP A OIA MAX rapid test kits for use in this study free of charge.Objectives: To evaluate the utility of rapid antigen detection testing (RADT) for the diagnosis of group A streptococcal (GAS) pharyngitis in pediatric outpatient clinics in four countries with varied socio-economic and geographic profiles. Methods: We prospectively evaluated the utility of a commercial RADT in children aged 2-12 years presenting with symptoms of pharyngitis to urban outpatient clinics in Brazil, Croatia, Egypt, and Latvia between August 2001 and December 2005. We compared the performance of the RADT to culture using diagnostic and agreement statistics, including sensitivity, specificity, and positive and negative predictive values. The Centor scores for GAS diagnosis were used to assess the potential effect of spectrum bias on RADT results. Results: Two thousand four hundred and seventy-two children were enrolled at four sites. The prevalence of GAS by throat culture varied by country (range 24.5-39.4%) and by RADT (range 23.9-41.8%). Compared to culture, RADT sensitivity ranged from 72.4% to 91.8% and specificity ranged from 85.7% to 96.4%. The positive predictive value ranged from 67.9% to 88.6% and negative predictive value ranged from 88.1% to 95.7%. Conclusions: In limited-resource regions where microbiological diagnosis is not feasible or practical, RADTs should be considered an option that can be performed in a clinic and provide timely results.publishersversionPeer reviewe

    Emplacement of inflated Pāhoehoe flows in the Naude’s Nek Pass, Lesotho remnant, Karoo continental flood basalt province: use of flow-lobe tumuli in understanding flood basalt emplacement

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    Physical volcanological features are presented for a 710-m-thick section, of the Naude’s Nek Pass, within the lower part of the Lesotho remnant of the Karoo Large Igneous Province. The section consists of inflated pāhoehoe lava with thin, impersistent sedimentary interbeds towards the base. There are seven discreet packages of compound and hummocky pāhoehoe lobes containing flow-lobe tumuli, making up approximately 50% of the section. Approximately 45% of the sequence consists of 14 sheet lobes, between 10 and 52-m-thick. The majority of the sheet lobes are in two packages indicating prolonged periods of lava supply capable of producing thick sheet lobes. The other sheet lobes are as individual lobes or pairs, within compound flows, suggesting brief increases in lava supply rate. We suggest, contrary to current belief, that there is no evidence that compound flows are proximal to source and sheet lobes (simple flows) are distal to source and we propose that the presence of flow-lobe tumuli in compound flows could be an indicator that a flow is distal to source. We use detailed, previously published, studies of the Thakurvadi Formation (Deccan Traps) as an example. We show that the length of a lobe and therefore the sections that are ‘medial or distal to source’ are specific to each individual lobe and are dependent on the lava supply of each eruptive event, and as such flow lobe tumuli can be used as an indicator of relative distance from source
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