542 research outputs found

    MEASUREMENT OF AGRICULTURAL TOTAL FACTOR PRODUCTIVITY GROWTH INCORPORATING ENVIRONMENTAL FACTORS: A NUTRIENTS BALANCE APPROACH

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    This paper develops a new measure of total factor productivity growth in agricultural production which incorporates environmental effects. The new measure is called the Total Factor Nutrient-Orientated Productivity (TFNP) Index, and incorporates a materials balance condition. TFNP measures changes in nutrient-orientated efficiency and can be decomposed into efficiency change (EC), technological change (TC) and nutrient-orientated technological change (NTC) components. An empirical analysis, involving country-level data from OECD countries during 1990-2003, is provided using DEA methods. Estimates of mean technical and nutrient-orientated efficiency are 0.798 and 0.526, respectively. Estimated mean TFNP growth is 1.5% per year, with nutrient-orientated technological progress contributing 0.8%.Total factor productivity, environment, nutrient balance, DEA, Productivity Analysis, Environmental Economics and Policy,

    Correlating heatwaves and relative humidity with suicide (fatal intentional self-harm)

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    Empirical evidence suggests that the effects of anthropogenic climate change, and heat in particular, could have a significant impact on mental health. This article investigates the correlation between heatwaves and/or relative humidity and suicide (fatal intentional self-harm) on a global scale. The covariance between heat/humidity and suicide was modelled using a negative binomial Poisson regression with data from 60 countries between 1979-2016. Statistically significant increases and decreases in suicide were found, as well as many cases with no significant correlation. We found that relative humidity showed a more significant correlation with suicide compared to heatwaves and that both younger age groups and women seemed to be more significantly affected by changes in humidity and heatwave counts in comparison with the rest of the population. Further research is needed to provide a larger and more consistent basis for epidemiological studies; to understand better the connections among heat, humidity and mental health; and to explore in more detail which population groups are particularly impacted and why

    Fine mapping of a grain weight quantitative trait locus, qGW6, using near isogenic lines derived from Oryza rufipogon IRGC105491 and Oryza sativa cultivar MR219

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    Grain weight is a major component of rice grain yield and is controlled by quantitative trait loci. Previously, a rice grain weight quantitative trait locus (qGW6) was detected near marker RM587 on chromosome 6 in a backcross population (BC2F2) derived from a cross between Oryza rufipogon IRGC105491 and O. sativa cv. MR219. Using a BC2F5 population, qGW6 was validated and mapped to a region of 4.8 cM (1.2 Mb) in the interval between RM508 and RM588. Fine mapping using a series of BC4F3 near isogenic lines further narrowed the interval containing qGW6 to 88 kb between markers RM19268 and RM19271.1. According to the Duncan multiple range test, 8 BC4F4 near isogenic lines had significantly higher 100-grain weight (4.8 to 7.5% over MR219) than their recurrent parent, MR219 (P < 0.05). According to the rice genome automated annotation database, there are 20 predicted genes in the 88-kb target region, and 9 of them have known functions. Among the genes with known functions in the target region, in silico gene expression analysis showed that 9 were differentially expressed during the seed development stage(s) from gene expression series GSE6893; however, only 3 of them have known functions. These candidates provide targets for further characterization of qGW6, which will assist in understanding the genetic control of grain weight in rice

    The chagas disease study landscape: A systematic review of clinical and observational antiparasitic treatment studies to assess the potential for establishing an individual participant-level data platform

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    Background: Chagas disease (CD), caused by the parasite Trypanosoma cruzi, affects ~6–7 million people worldwide. Significant limitations still exist in our understanding of CD. Harnessing individual participant data (IPD) from studies could support more in-depth analyses to address the many outstanding research questions. This systematic review aims to describe the characteristics and treatment practices of clinical studies in CD and assess the breadth and availability of research data for the potential establishment of a data-sharing platform. Methodology/Principal findings This review includes prospective CD clinical studies published after 1997 with patients receiving a trypanocidal treatment. The following electronic databases and clinical trial registry platforms were searched: Cochrane Library, PubMed, Embase, LILACS, Scielo, Clintrials. gov, and WHO ICTRP. Of the 11,966 unique citations screened, 109 (0.9%) studies (31 observational and 78 interventional) representing 23,116 patients were included. Diagnosis for patient enrolment required 1 positive test result in 5 (4.6%) studies (2 used molecular method, 1 used molecular and serology, 2 used serology and parasitological methods), 2 in 60 (55.0%), 3 in 14 (12.8%) and 4 or more in 4 (3.7%) studies. A description of treatment regimen was available for 19,199 (83.1%) patients, of whom 14,605 (76.1%) received an active treatment and 4,594 (23.9%) were assigned to a placebo/no-treatment. Of the 14,605 patients who received an active treatment, benznidazole was administered in 12,467 (85.4%), nifurtimox in 825 (5.6%), itraconazole in 284 (1.9%), allopurinol in 251(1.7%) and other drugs in 286 (1.9%). Assessment of efficacy varied largely and was based primarily on biological outcome; parasitological efficacy relied on serology in 67/85 (78.8%) studies, molecular methods in 52/85 (61.2%), parasitological in 34/85 (40.0%), microscopy in 3/85 (3.5%) and immunohistochemistry in 1/85 (1.2%). The median time at which parasitological assessment was carried out was 79 days [interquartile range (IQR): 30–180] for the first assessment, 180 days [IQR: 60–500] for second, and 270 days [IQR: 18–545] for the third assessment. Conclusions/Significance This review demonstrates the heterogeneity of clinical practice in CD treatment and in the conduct of clinical studies. The sheer volume of potential IPD identified demonstrates the potential for development of an IPD platform for CD and that such efforts would enable indepth analyses to optimise the limited pharmacopoeia of CD and inform prospective data collection.Fil: Maguire, Brittany J.. University of Oxford; Reino UnidoFil: Dahal, Prabin. University of Oxford; Reino UnidoFil: Rashan, Sumayyah. University of Oxford; Reino UnidoFil: Ngu, Roland. University of Oxford; Reino UnidoFil: Boon, Anca. University of Oxford; Reino UnidoFil: Forsyth, Colin. No especifíca;Fil: Strub Wourgraft, Nathalie. No especifíca;Fil: Chatelain, Eric. No especifíca;Fil: Barreira, Fabiana. No especifíca;Fil: Sosa-Estani, Sergio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Epidemiología y Salud Pública. Instituto de Efectividad Clínica y Sanitaria. Centro de Investigaciones en Epidemiología y Salud Pública; ArgentinaFil: Guerin, Philippe J.. University of Oxford; Reino Unid

    Factors associated with severity of hepatic fibrosis in people with chronic hepatitis C infection

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    The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.OBJECTIVE: To determine factors associated with hepatic fibrosis development in people with chronic hepatitis C virus (HCV) infection. METHODS: As a requirement for access to interferon therapy through the S100 scheme in Australia, individual pretreatment demographic and clinical information was collected on 2986 patients from 61 hospital-based liver clinics from 1 October 1994 through 31 December 1996. Patients with both a hepatic fibrosis score and an estimated duration of HCV infection (910) were divided into 540 with no or minimal hepatic fibrosis (stage 0–1) and 370 with moderate to severe hepatic fibrosis (stage 2–3). Seven factors were examined: age at HCV infection, sex, ethnicity, source of infection, duration of infection, alcohol intake, and mean ALT level. A further analysis was performed for all 1135 patients with a hepatic fibrosis score disregarding age at and duration of HCV infection. RESULTS: In multivariate analysis, four factors were significantly associated with moderate to severe hepatic fibrosis: age at infection (OR, 2.33 for age 31–40 years, 5.27 for age > 40 years, and 0.20 for age 30 years, compared with 3 times, compared with 1.5–2 times the upper limit of normal). In the analysis disregarding age at HCV infection and duration of HCV infection, older age was strongly associated with moderate to severe hepatic fibrosis (OR, 2.32 for age 36–40 years, 2.46 for age 41–50 years, 7.87 for age 51–60 years, and 7.15 for age > 60 years, compared with 16–30 years). There was no association in either analysis with sex or source of HCV infection. CONCLUSION: These factors may assist in targeting patients for both liver biopsy-based investigation and therapeutic intervention.Mark Danta, Gregory J Dore, Lisa Hennessy, Yueming Li, Chris R Vickers, Hugh Harley, Meng Ngu, William Reed, Paul V Desmond, William Sievert, Geoff C Farrell, John M Kaldor and Robert G Bate

    From Appearance to Essence

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    Truth discovery has been widely studied in recent years as a fundamental means for resolving the conflicts in multi-source data. Although many truth discovery methods have been proposed based on different considerations and intuitions, investigations show that no single method consistently outperforms the others. To select the right truth discovery method for a specific application scenario, it becomes essential to evaluate and compare the performance of different methods. A drawback of current research efforts is that they commonly assume the availability of certain ground truth for the evaluation of methods. However, the ground truth may be very limited or even impossible to obtain, rendering the evaluation biased. In this article, we present CompTruthHyp, a generic approach for comparing the performance of truth discovery methods without using ground truth. In particular, our approach calculates the probability of observations in a dataset based on the output of different methods. The probability is then ranked to reflect the performance of these methods. We review and compare 12 representative truth discovery methods and consider both single-valued and multi-valued objects. The empirical studies on both real-world and synthetic datasets demonstrate the effectiveness of our approach for comparing truth discovery methods.Xiu Susie Fang, Quan Z. Sheng, Xianzhi Wang, Wei Emma Zhang, Anne H. H. Ngu, Jian Yan

    Gender disparities in pulmonary hypertension at a tertiary centre in Cameroon

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    Background. Pulmonary hypertension (PH) is a potent cause of heart failure and has been little investigated in the African setting. Objective. To investigate the effects of gender on the clinical presentation, echocardiographic features and outcomes of patients with PH in Douala, Cameroon. Methods. A prospective cohort study was conducted from March 2012 to December 2013 as part of the Pan African Pulmonary Hypertension Cohort study. PH was diagnosed by echocardiography and defined as a right ventricular systolic pressure &gt;35 mmHg in the absence of acute right heart failure. Patients were followed up for a maximum of 12 months for primary endpoint mortality. Results. In total, 130 patients with PH were recruited; 71 (54.6%) were women. The median age was 59.2 years for men and 58.3 years for women (p=0.76). Active smoking and alcohol use were more frequent in men than women (both p&lt;0.001), but women had greater exposure to indoor cooking fumes than men (p&lt;0.001). Previous tuberculosis infection (11.3% v. 1.7%) and S3 gallop rhythm (30.9% v. 11.9%) were more common in women (both p&lt;0.03). Women had a significantly higher mean systolic blood pressure (134 mmHg v. 125 mmHg; p=0.04) and pulse pressure (53.8 mmHg v. 44.9 mmHg; p=0.01) and a lower mean haemoglobin concentration (10.4 g/dL v. 12.4 g/dL; p&lt;0.05) compared with men. Echocardiographic left ventricular (LV) systolic dysfunction was more frequent in men: mean LV ejection fraction 42.6% v. 51.5% (p=0.01) and mean fractional shortening 21.4% v. 28.6% (p=0.01). The overall mortality rate was 20.3%, and rates were similar in the two groups (Kaplan-Meier log rank 1.1; p=0.30). Conclusions. Despite differences in baseline characteristics including cardiovascular risk factors, mortality rates on follow-up were similar in men and women in this study. However, these different baseline characteristics probably suggest differences in the pathogenesis of PH in men and women in our setting that need further investigation.S Afr Med J 2017;107(10):892-89

    Case Study of Modular Pre-cast Concrete On-Site Stormwater Detention System during Monsoon Season in Southeast Asia

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    On-site stormwater detention system within a residential property is meant for an environmental protection device that temporarily stores stormwater within the property lot to mitigate flash flood, particularly during rainy seasons brought by the northeast monsoon. A field test was constructed in a house’s car porch with a 4.40 m x 4.70 m x 0.45 m tank filled with precast-concrete modular units with an effective storage volume of 3.97 m3. The system received water from a 95 m2 house roof via 0.1 m diameter pipe, discharged water via 0.05 m diameter pipe. It had recorded six observed storm events coincided with the 2019/2020 monsoon season that consisted 20–50 mm peak hourly rainfall, 0.0007–0.0018 m3 s-1 inflow, 0.0005–0.0012 m3 s-1 outflow and 0.21–0.47 m water level. Another four historical storm events coincided with the monsoon from 2015–2017 were sourced to augment the analysis. A computer model developed using the storm water management model was calibrated and verified using the six observed events. The Kolmogorov-Smirnov goodness of fit tests between the observed and modelled cumulative distributions had produced 0.01–0.14 maximum vertical distances that were lower than the 0.41–0.68 critical values indicating close matches. As such, the calibrated and verified model was used to simulate the historical storm events with 40–50 mm peak hourly rainfall and produced 0.0010–0.0013 m3 s-1 inflow, 0.00072–0.00076 m3 s-1 outflow and 0.41–0.45 m water level. By combining the field test and computer simulation model, it was found the system was able to contain all stormwaters from northeast monsoon. However, it had a weakness which the system was approaching its maximum capacity once the peak hourly rainfall exceeded 45 mm. With such a procedure in place, improvement could be carried out

    Na+ and K+ transport and maturation stage ameloblast modulation

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    Introduction: Enamel mineralization requires calcium transport into the extracellular matrix for the synthesis of hydroxyapatite (HA) crystals. Formation of HA releases protons into the matrix, which are then neutralized when ameloblasts modulate from cells with apical invaginations, the so-called ruffle-ended ameloblasts (RE), to smooth-ended ameloblasts (SE). Ameloblast modulation is associated with the translocation of the calcium exchanger Nckx4 to the apical border of RE, to remove Na+ from the enamel matrix in exchange for Ca2+ and K+. As enamel matures, Na+ and K+ in the matrix progressively decrease. However, the transporter to remove K+ from mineralizing enamel has not been identified.Methods: Expression of K+ exchangers and channels in secretory and maturation stage of enamel organs were compared following an RNA-seq analysis. Kcnj15, which encodes the Kir4.2 inwardly rectifying K+ channel, was found to be the most upregulated internalizing K+ transporter in maturation stage of enamel organs. Kir4.2 was immunolocalized in wt, Nckx4−/−, Wdr72−/−, and fluorosed ameloblasts. Regulation of Wdr72 expression by pH was characterized in vitro and in vivo.Results: Kir4.2 immunolocalized to the apical border of wild type (wt) mouse RE and cytosol of SE, a spatial distribution pattern shared by NCKX4. In Nckx4−/− ameloblasts, Kir4.2 also localized to the apical surface of RE and cytosol of SE. However, in fluorosed and Wdr72−/− ameloblasts, in which vesicle trafficking is disrupted, Kir4.2 remained in the cytosol. In vitro, Wdr72 was upregulated in LS8 cells cultured in medium with a pH 6.2, which is the pH of the enamel matrix underlying RE, as compared to pH 7.2 under SE.Conclusion: Taken together these results suggest that Kir4.2 participates in K+ uptake by maturation ameloblasts, and that K+ and Na+ uptake by Kir4.2 and Nckx4, respectively, may be regulated by pH through WDR72-mediated endocytosis and membrane trafficking
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