669 research outputs found

    Breeding Improved Varieties Of White Clover.

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    End of Project ReportWhite clover is one of the most nutritious species available in grassland/ruminant production systems. In association with grass, this species increases protein, mineral content, intake and nutrient value of the total forage. Because of its nitrogen fixing capacity, white clover has the potential to reduce, or in the case of organic systems, eliminate the need for inorganic nitrogen fertilizer on grazed grassland. Grassland-based animal production is a major part of the Irish agricultural economy, consequently any improvement in this legume has large potential benefit in this sector. The background, methodology, objectives and output of the current Teagasc, Oak Park white clover breeding programme are outlined. Five varieties have been released and are currently on Recommended Lists in Ireland and elsewhere. Aran, first released in 1981, has remained the highest yielding clover variety in UK trials, it is also widely grown in New Zealand, Australia and France as well as Ireland and UK. Avoca has shown very good yield and persistency under a range of managements and is widely used in Ireland and UK. Chieftain, the most recently released variety, has given 25% more clover yield than the control under lax defoliation (simulated grazing) management in UK Recommended List trials. In parallel with the breeding programme, research on nitrogen fixation and development of inbred lines in this species was undertaken. A brief summary of some of the results is included in this report.DLF-TRIFOLIU

    Breeding Improved Varieties of Perennial Ryegrass.

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    End of Project ReportThe background, methodology and objectives of the current ryegrass breeding programme are outlined. Six varieties have been released and are currently on Recommended Lists in Ireland and elsewhere. The varieties have shown improvement in yield and yield distribution: these traits are important in the context of improving the productive potential of Irish grasslands. In parallel with the breeding programme, research on projects which is related to future selection strategy was undertaken. The results of this research on hybrid breeding system and quality objectives are summarised

    An assessment of the interaction between socio-economic status and diabetes mellitus: The impact on cardiovascular disease, microvascular complications and diabetes prevalence

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    This thesis consists of four studies addressing the relationship between diabetes and socio-economic status. 1. Name: Cardiac risk factor clustering in diabetic persons of low socio-economic status (SES). Objective: To ascertain the prevalence of obesity, smoking, hypertension, hyperglycaemia and hyperlipidaemia in a cohort of diabetic patients and in seven socio-economic categories for insulin dependent diabetes mellitus (IDDM) and non-insulin dependent diabetes mellitus (NIDDM). Conclusions: This study confirmed an inverse gradient of exposure to the major CAD risk factors and SES

    Incorporating metamorphism in geodynamic models: the mass conservation problem

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    Geodynamic models incorporating metamorphic phase transformations almost invariably assume the validity of the Boussinesq approximation that violates conservation of mass. In such models metamorphic density changes take place without volumetric effects. We assess the impact of the Boussinesq approximation by comparing models of orogeny accompanied by lower crustal eclogitization both with and without the approximation. Our results demonstrate that the approximation may cause errors approaching 100 per cent in characteristic measures of orogenic shape. Mass conservation errors in Boussinesq models amplify with model time. Mass conservative models of metamorphism are therefore essential to understand long-term tectonic evolution and to assess the importance of the different geodynamic processe

    Growth Route Toward III-V Multispectral Solar Cells on Silicon

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    To date, high efficiency multijunction solar cells have been developed on Ge or GaAs substrates for space applications, and terrestrial applications are hampered by high fabrication costs. In order to reduce this cost, we propose a breakthrough technique of III-V compound heteroepitaxy on Si substrates without generation of defects critical to PV applications. With this technique we expect to achieve perfect integration of heterogeneous Ga1-xInxAs micro-crystals on Si substrates. In this paper, we show that this is the case for x=0. GaAs crystals were grown by Epitaxial Lateral Overgrowth on Si (100) wafers covered with a thin SiO2 nanostructured layer. The cristallographic structure of these crystals is analysed by MEB and TEM imaging. Micro-Raman and Micro-Photomuminescence spectra of GaAs crystals grown with different conditions are compared with those of a reference GaAs wafer in order to have more insight on eventual local strains and their cristallinity. This work aims at developping building blocks to further develop a GaAs/Si tandem demonstrator with a potential conversion efficiency of 29.6% under AM1.5G spectrum without concentration, as inferred from our realistic modeling. This paper shows that Epitaxial Lateral Overgrowth has a very interesting potential to develop multijunction solar cells on silicon approaching the today 30.3% world record of a GaInP/GaAs tandem cell under the same illumination conditions, but on a costlier substrate than silicon.Comment: Preprint of the 28th EUPVSEC proceedings, September 2013, Paris, France. (5 pages

    Characterisation of adipocyte-derived extracellular vesicles released pre- and post-adipogenesis

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    Extracellular vesicles (EVs) are submicron vesicles released from many cell types, including adipocytes. EVs are implicated in the pathogenesis of obesity-driven cardiovascular disease, although the characteristics of adipocyte-derived EVs are not well described. We sought to define the characteristics of adipocyte-derived EVs before and after adipogenesis, hypothesising that adipogenesis would affect EV structure, molecular composition and function. Using 3T3-L1 cells, EVs were harvested at day 0 and day 15 of differentiation. EV and cell preparations were visualised by electron microscopy and EVs quantified by nanoparticle tracking analysis (NTA). EVs were then assessed for annexin V positivity using flow cytometry; lipid and phospholipid composition using 2D thin layer chromatography and gas chromatography; and vesicular protein content by an immuno-phenotyping assay. Pre-adipogenic cells are connected via a network of protrusions and EVs at both time points display classic EV morphology. EV concentration is elevated prior to adipogenesis, particularly in exosomes and small microvesicles. Parent cells contain higher proportions of phosphatidylserine (PS) and show higher annexin V binding. Both cells and EVs contain an increased proportion of arachidonic acid at day 0. PREF-1 was increased at day 0 whilst adiponectin was higher at day 15 indicating EV protein content reflects the stage of adipogenesis of the cell. Our data suggest that EV production is higher in cells before adipogenesis, particularly in vesicles <300 nm. Cells at this time point possess a greater proportion of PS (required for EV generation) whilst corresponding EVs are enriched in signalling fatty acids, such as arachidonic acid, and markers of adipogenesis, such as PREF-1 and PPARγ

    Childrens friendships in super-diverse localities: Encounters with social and ethnic difference

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    This article explores how children make, manage, or avoid friendships in super-diverse primary school settings. We draw on interviews and pictorial data from 78 children, aged 8–9 years across three local London primary schools to identify particular friendship groupings and the extent to which they followed existing patterns of social division. Children in the study did recognise social and cultural differences, but their friendship perceptions, affections, conflicts and practices meant that the way in which difference impacted relationships was partial and unstable. Friendship practices in the routine settings of school involved interactions across difference, but also entrenchments around similarity

    Observations of the unidentified gamma-ray source TeV J2032+4130 by VERITAS

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    TeV J2032+4130 was the first unidentified source discovered at very high energies (VHE; E >> 100 GeV), with no obvious counterpart in any other wavelength. It is also the first extended source to be observed in VHE gamma rays. Following its discovery, intensive observational campaigns have been carried out in all wavelengths in order to understand the nature of the object, which have met with limited success. We report here on a deep observation of TeV J2032+4130, based on 48.2 hours of data taken from 2009 to 2012 by the VERITAS (Very Energetic Radiation Imaging Telescope Array System) experiment. The source is detected at 8.7 standard deviations (σ\sigma) and is found to be extended and asymmetric with a width of 9.5′^{\prime}±\pm1.2′^{\prime} along the major axis and 4.0′^{\prime}±\pm0.5′^{\prime} along the minor axis. The spectrum is well described by a differential power law with an index of 2.10 ±\pm 0.14stat_{stat} ±\pm 0.21sys_{sys} and a normalization of (9.5 ±\pm 1.6stat_{stat} ±\pm 2.2sys_{sys}) ×\times 10−13^{-13}TeV−1^{-1} cm−2^{-2} s−1^{-1} at 1 TeV. We interpret these results in the context of multiwavelength scenarios which particularly favor the pulsar wind nebula (PWN) interpretation
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