4,555 research outputs found

    Detection of TYLCV in Ten Genotypes of Tomato (Solanum spp L.) using Serological and Molecular Techniques in a Coastal Savanna Zone of Ghana

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    Use of resistant varieties is a proven way of controlling the tomato yellow leaf curl virus (TYLCV), which causes a devastating disease of tomato in tropical and warm temperate regions, resulting in significant yield losses. However, breeding for resistant varieties is slow due to lack of effective methods of virus detection that will lead to efficient selection of desired varieties. A study was conducted to evaluate the susceptibility or otherwise of ten tomato genotypes to TYLCV under field conditions. The ten (10) tomato genotypes were planted in the field and left to natural infection by whitefly vectors. Leaf samples were collected from symptomatic as well as asymptomatic plants at five weeks after transplanting (5WAT) for analysis by serological and nucleic acid-based techniques. Triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA) detected TYLCV in five out of ten genotypes while polymerase chain reaction using six primers (virus-specific and degenerate) detected the virus in eight out of ten genotypes. The polymerase chain reaction (PCR) technique detected the virus in three samples that tested negative to TAS-ELISA, implying its enhanced sensitivity. A correlation of symptom expression in the field to the presence of TYLCV in test samples led to an effective and unbiased selection of tolerant/resistant genotypes which can be used in further breeding programmes. The study highlights the need for a combination of two or more detection techniques in breeding to enhance the efficiency of selection of TYLC-resistant lines. Keywords: Tomato yellow leaf curl virus, enzyme-linked immunosorbent assay, polymerase chain reaction, genotypes, resistant varieties, Solanum lycopersicon

    Prediction Models for Water Erosion Risk Management: A Review

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    In order to estimate the potential soil erosion hazard of an area, erosion prediction models are needed. Various models have been used by researchers, which ranges from mathematical and conceptual simple approaches to complex models that try to include the complexities of the real world. Six (6) models are reviewed in relation to their suitability for use. The KINEROS, CORINE and EUROSEM were best suited for water erosion risk prediction in cultivated soils. On the other hand, the KINEROS, PESERA, CORINE and EUROSEM were found to be applicable in all sectors (Agronomy, water resources management and road construction) highlighted. The GLASOD had the least applicability with respect to this study.Keywords: Water Erosion, sediment transport models, Model structure and suitability for us

    Prevention and management of excessive gestational weight gain: a survey of overweight and obese pregnant women

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    Background - Excessive gestational weight gain is associated with adverse infant, childhood and maternal outcomes and research to develop interventions to address this issue is ongoing. The views of women on gestational weight gain and the resources they would consider helpful in addressing this are however largely unknown. This survey aimed to determine the views of newly pregnant women, living in areas of social disadvantage, on 1) their current body weight and potential gestational weight gain and 2) the resources or interventions they would consider helpful in preventing excessive gestational weight gain. Methods - A convenience sample of overweight and obese pregnant women living in Fife, UK, were invited to complete a short anonymised questionnaire at their 12 week booking visit. Results - 428 women, BMI>25 kg/m2, completed the questionnaire. Fifty-four per cent of respondents were obese (231) and 62% were living in areas of mild to moderate deprivation. Over three-quarters of participants felt dissatisfied with their current weight (81%). The majority of women (60%) expressed some concern about potential weight gain. Thirty-nine percent were unconcerned about weight gain during their pregnancy, including 34 women (19%) who reported having retained weight gained in earlier pregnancies. Amongst those concerned about weight gain advice on physical activity (41%) and access to sports/leisure facilities were favoured resources (36%). Fewer women (12%) felt that group sessions on healthy eating or attending a clinic for individualised advice (14%) would be helpful. "Getting time off work" was the most frequently cited barrier (48%) to uptake of resources other than leaflets. Conclusions- These data suggest a lack of awareness amongst overweight and obese women regarding excessive gestational weight gain. Monitoring of gestational weight gain, and approaches for its management, should be formally integrated into routine antenatal care. Barriers to the uptake of resources to address weight gain are numerous and must be considered in the design of future interventions and services

    Tunicates push the limits of animal evo-devo

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    The phylum to which humans belong, Chordata, takes its name from one of the major shared derived features of the group, the notochord. All chordates have a notochord, at least during embryogenesis, and there is little doubt about notochord homology at the morphological level. A study in BMC Evolutionary Biology now shows that there is greater variability in the molecular genetics underlying notochord development than previously appreciated

    Multivariate truncated moments problems and maximum entropy

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    We characterize the existence of the Lebesgue integrable solutions of the truncated problem of moments in several variables on unbounded supports by the existence of some maximum entropy -- type representing densities and discuss a few topics on their approximation in a particular case, of two variables and 4th order moments.Comment: Revised version, to appear in Analysis and Mathematical Physic

    Hyperhomocysteinaemia is associated with coronary events in type 2 diabetes

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    Objectives. Amongst nondiabetic individuals, a high serum homocysteine concentration is an independent but relatively weak risk factor for coronary events. However, it is not known whether homocysteine increases risk of coronary events in type 2 diabetes. Therefore, we examined the combined effect of homocysteine and type 2 diabetes on risk of fatal and nonfatal coronary events. Subjects. We assessed the 10-year risk of coronary events associated with homocysteine amongst diabetic (n = 140) and nondiabetic (n = 361) individuals. Design. We did this in the Hoorn Study, a population-based study of glucose tolerance and related complications in Caucasian men and women aged 50-75 years. Results. The incidence rate for coronary events was 2.63 (29 of 140) per 100 person-years amongst diabetic and 1.29 (42 of 361) amongst nondiabetic individuals. Amongst diabetic individuals, risk of coronary events increased 28% for each 5-μmol

    Limited Effects of Set Shifting Training in Healthy Older Adults

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    Our ability to flexibly shift between tasks or task sets declines in older age. As this decline may have adverse effects on everyday life of elderly people, it is of interest to study whether set shifting ability can be trained, and if training effects generalize to other cognitive tasks. Here, we report a randomized controlled trial where healthy older adults trained set shifting with three different set shifting tasks. The training group (n = 17) performed adaptive set shifting training for 5 weeks with three training sessions a week (45 min/session), while the active control group (n = 16) played three different computer games for the same period. Both groups underwent extensive pre-and post-testing and a 1-year follow-up. Compared to the controls, the training group showed significant improvements on the trained tasks. Evidence for near transfer in the training group was very limited, as it was seen only on overall accuracy on an untrained computerized set shifting task. No far transfer to other cognitive functions was observed. One year later, the training group was still better on the trained tasks but the single near transfer effect had vanished. The results suggest that computerized set shifting training in the elderly shows long-lasting effects on the trained tasks but very little benefit in terms of generalization

    Abundance, rarity and invasion debt among exotic species in a patchy ecosystem

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    Community assembly through species invasions is a long-term process, for which vital information regarding future trends can be contained in current patterns. Using comparative analyses of native and exotic plant assemblages from meadow patches on islands in British Columbia, Canada, we examined multiple lines of evidence for ‘invasion debt’, a latent expansion of exotic species populations. We show that: (1) short-dispersing species are underrepresented compared to their long-dispersing counterparts in exotic species only; (2) among species that are invasive elsewhere in North America, a greater proportion of long dispersers are common in the study area and a greater proportion of short dispersers are rare; and (3) time since arrival in the study region is positively related to number of occurrences in exotic species. In addition, we show that a suite of exotic species possesses the facility of rapid long-distance dispersal and ability to establish viable populations on even the most isolated and least disturbed patches. While some highly-dispersive exotic species can rapidly colonize new areas, short dispersers appear to exhibit invasion debt, with their potential distributions only being realized in the long term. Removing or even reducing populations of many rapid colonizers could be extremely difficult; however, for species exhibiting patterns most consistent with invasion debt, an opportunity exists for monitoring and removal to help reduce potential competition with native species

    Circulating Progenitor Cells Identify Peripheral Arterial Disease in Patients With Coronary Artery Disease

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    RATIONALE: Peripheral arterial disease (PAD) is a clinical manifestation of extracoronary atherosclerosis. Despite sharing the same risk factors, only 20% to 30% of patients with coronary artery disease (CAD) develop PAD. Decline in the number of bone marrow–derived circulating progenitor cells (PCs) is thought to contribute to the pathogenesis of atherosclerosis. Whether specific changes in PCs differentiate patients with both PAD and CAD from those with CAD alone is unknown. OBJECTIVE: Determine whether differences exist in PCs counts of CAD patients with and without known PAD. METHODS AND RESULTS: 1497 patients (mean age: 65 years; 62% men) with known CAD were identified in the Emory Cardiovascular Biobank. Presence of PAD (n=308) was determined by history, review of medical records, or imaging and was classified as carotid (53%), lower extremity (41%), upper extremity (3%), and aortic disease (33%). Circulating PCs were enumerated by flow cytometry. Patients with CAD and PAD had significantly lower PC counts compared with those with only CAD. In multivariable analysis, a 50% decrease in cluster of differentiation 34 (CD34+) or CD34+/vascular endothelial growth factor receptor-2 (VEGFR2+) counts was associated with a 31% (P=0.032) and 183% (P=0.002) increase in the odds of having PAD, respectively. CD34+ and CD34+/VEGFR2+ counts significantly improved risk prediction metrics for prevalent PAD. Low CD34+/VEGFR2+ counts were associated with a 1.40-fold (95% confidence interval, 1.03–1.91) and a 1.64-fold (95% confidence interval, 1.07–2.50) increases in the risk of mortality and PAD-related events, respectively. CONCLUSIONS: PAD is associated with low CD34+ and CD34+/VEGFR2+ PC counts. Whether low PC counts are useful in screening for PAD needs to be investigated
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