196 research outputs found

    Implications of investigating pollination and cross compatibility in the almond varieties of Afghanistan

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    Survey and collection of almond accessions for a National Collection of Fruit and Nuts of Afghanistan began in 2007. Investigations into cross compatibility of almond accessions began in 2008 on in situ collected exemplar trees, and in 2010 on trees in the ex situ collections. The methods varied in relation to specific trials, nevertheless as an average 150 flower buds were isolated ahead of flowering on 7 one-year-old shoots per tree, and used as pollen donors or receptors. The initial trials on in situ accessions were performed on one single tree per variety, while six trees were used for the tests carried on in the ex situ collections. Fruit set percentage from self-pollination, cross-pollination and open pollination was calculated. All native Afghan varieties tested were shown to be self incompatible. Various problems related to weather and other conditions worked against a comprehensive testing of all combinations of varieties, although many useful and surprising conclusions were reached

    Isotope effects and the charge gap formation in the charge ordered phase of colossal magnetoresistance manganites

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    Giant oxygen isotope effects observed in colossal magnetoresistance manganites are investigated by employing the combined model of the double exchange and interacting lattice polaron mechanism. We have shown that the isotope effects on TC T_C in the metallic phase and TCO T_{CO} in the charge ordered phase of manganites can be explained well in terms of the double exchange and polaron narrowing factors with reasonable physical parameters.Comment: 5 pages, 3 figure

    Bounds on Four-Fermion Contact Interactions Induced by String Resonances

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    Based on tree-level open-string scattering amplitudes in the low string-scale scenario, we derive the massless fermion scattering amplitudes. The amplitudes are required to reproduce those of the Standard Model at tree level in the low energy limit. We then obtain four-fermion contact interactions by expanding in inverse powers of the string scale and explore the constraints on the string scale from low energy data. The Chan-Paton factors and the string scale are treated as free parameters. We find that data from the neutral and charged current processes at HERA, Drell-Yan process at the Tevatron, and from LEP-II put lower bounds on the string scale M_S >= 0.9-1.3 TeV for typical values of the Chan-Paton factors, which are comparable to Tevatron bounds on Z' and W' masses.Comment: 13 pages, 1 ps figure, version to appear in PR

    Seasonality of depressive symptoms in women but not in men: a cross-sectional study in the UK Biobank cohort

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    Background: We examined whether seasonal variations in depressive symptoms occurred independently of demographic and lifestyle factors, and were related to change in day length and/or outdoor temperature. Methods: In a cross-sectional analysis of >150,000 participants of the UK Biobank cohort, we used the cosinor method to assess evidence of seasonality of a total depressive symptoms score and of low mood, anhedonia, tenseness and tiredness scores in women and men. Associations of depressive symptoms with day length and mean outdoor temperature were then examined. Results: Seasonality of total depressive symptom scores, anhedonia and tiredness scores was observed in women but not men, with peaks in winter. In women, increased day length was associated with reduced low mood and anhedonia scores, independent of demographic and lifestyle factors. For women, longer day length was associated with increased tiredness. Associations with day length were not independent of the average outdoor temperature preceding assessment. Limitations: This was a cross-sectional investigation – longitudinal studies of within-subject seasonal variation in mood are necessary. Outcome measures relied on self-report and measured only a subset of depressive symptoms. Conclusion: This large, population-based study provides evidence of seasonal variation in depressive symptoms in women. Shorter days were associated with increased feelings of low mood and anhedonia in women. Clinicians should be aware of these population-level sex differences in seasonal mood variations in order to aid recognition and treatment of depression and subclinical depressive symptoms

    Association of disrupted circadian rhythmicity with mood disorders, subjective wellbeing, and cognitive function: a cross-sectional study of 91 105 participants from the UK Biobank

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    Background: Disruption of sleep and circadian rhythmicity is a core feature of mood disorders and might be associated with increased susceptibility to such disorders. Previous studies in this area have used subjective reports of activity and sleep patterns, but the availability of accelerometer-based data from UK Biobank participants permits the derivation and analysis of new, objectively ascertained circadian rhythmicity parameters. We examined associations between objectively assessed circadian rhythmicity and mental health and wellbeing phenotypes, including lifetime history of mood disorder. Methods: UK residents aged 37–73 years were recruited into the UK Biobank general population cohort from 2006 to 2010. We used data from a subset of participants whose activity levels were recorded by wearing a wrist-worn accelerometer for 7 days. From these data, we derived a circadian relative amplitude variable, which is a measure of the extent to which circadian rhythmicity of rest–activity cycles is disrupted. In the same sample, we examined cross-sectional associations between low relative amplitude and mood disorder, wellbeing, and cognitive variables using a series of regression models. Our final model adjusted for age and season at the time that accelerometry started, sex, ethnic origin, Townsend deprivation score, smoking status, alcohol intake, educational attainment, overall mean acceleration recorded by accelerometry, body-mass index, and a binary measure of childhood trauma. Findings: We included 91 105 participants with accelerometery data collected between 2013 and 2015 in our analyses. A one-quintile reduction in relative amplitude was associated with increased risk of lifetime major depressive disorder (odds ratio [OR] 1·06, 95% CI 1·04–1·08) and lifetime bipolar disorder (1·11, 1·03–1·20), as well as with greater mood instability (1·02, 1·01–1·04), higher neuroticism scores (incident rate ratio 1·01, 1·01–1·02), more subjective loneliness (OR 1·09, 1·07–1·11), lower happiness (0·91, 0·90–0·93), lower health satisfaction (0·90, 0·89–0·91), and slower reaction times (linear regression coefficient 1·75, 1·05–2·45). These associations were independent of demographic, lifestyle, education, and overall activity confounders. Interpretation: Circadian disruption is reliably associated with various adverse mental health and wellbeing outcomes, including major depressive disorder and bipolar disorder. Lower relative amplitude might be linked to increased susceptibility to mood disorders

    Evidence of Color Coherence Effects in W+jets Events from ppbar Collisions at sqrt(s) = 1.8 TeV

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    We report the results of a study of color coherence effects in ppbar collisions based on data collected by the D0 detector during the 1994-1995 run of the Fermilab Tevatron Collider, at a center of mass energy sqrt(s) = 1.8 TeV. Initial-to-final state color interference effects are studied by examining particle distribution patterns in events with a W boson and at least one jet. The data are compared to Monte Carlo simulations with different color coherence implementations and to an analytic modified-leading-logarithm perturbative calculation based on the local parton-hadron duality hypothesis.Comment: 13 pages, 6 figures. Submitted to Physics Letters
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