598 research outputs found

    Genetic Diversity and Heterosis in Perennial Ryegrass

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    Plant breeders are concerned with the diversity among and within breeding populations, because it largely determines the future prospects of success in breeding programs. DNA markers provide a powerful tool for the assessment of genetic diversity. The relationship between genetic diversity and heterosis has been investigated in several species (Melchinger, 1999). In hybrid breeding programs divergent genepools have been established in the past, according to heterotic patterns based on testcross information. In the last decade it has been shown, that new breeding materials can be assigned to already existing gene pools using molecular markers. The phenomenon of heterosis has been of interest in grass breeding research for a long time, and the occurrence of heterosis has been demonstrated for particular crosses (review in Posselt, 2003). However, no attempts have been made to group perennial ryegrass populations according to diversity measures. So far, breeders have mostly combined diverse materials into a base population and applied intra-population improvement. Accidently, heterosis was captured in the new variety. For more reliable exploitation of heterosis in grasses, divergent genepools have to be established

    Millimeter interferometer observations of the magnetar 4U 0142+61

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    The Anomalous X‐ray Pulsar 4U 0142+61 is the only neutron star where it is believed that one of the long searched‐for ‘fallback’ disks has been detected in the mid‐IR by Wang et al. [1] using Spitzer. Such a disk originates from material falling back to the NS after the supernova. We search for cold circumstellar material in the 90 GHz continuum using the Plateau de Bure Interferometer. No millimeter flux is detected at the position of 4U 0142+61, the upper flux limit is 150 ÎŒJy corresponding to the 3σ noise rms level. The re‐processed Spitzer MIPS 24ÎŒm data presented previously by Wang et al. [2] show some indication of flux enhancement at the position of the neutron star, albeit below the 3σ statistical significance limit. At far infrared wavelengths the source flux densities are probably below the Herschel confusion limits

    Improving the provision of services to young people from refugee backgrounds with comorbid mental health and substance use problems: addressing the barriers

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    South Australia (SA) has resettled 151,134 refugees in the last ten years (Department of Immigration and Border Protection, Settlement reporting facility, 2014). Northern metropolitan Adelaide, an area which experiences significant social disadvantage, has received a significant number of (predominantly young) refugees. Research indicates that refugee youth are at elevated risk of mental health (MH) and alcohol and other drug (AOD) problems. These factors, along with the low socio-economic status of northern Adelaide, the number of refugee youth residing there, and the added complexity of treating comorbid MH and AOD problems (comorbidity) prompted this research. We investigated the barriers and facilitators to culturally responsive comorbidity care for these youth and whether the MH and AOD services were equipped to provide such support.This mixed-methods study employed semi-structured interviews with refugee youth and service providers and an online survey with managers of services. Thirty participants (15 refugee youth, 15 service providers) took part in the semi-structured interviews and 56 (40 complete, 16 partially-complete) in the survey.Thematic analysis of the interview data revealed the most commonly reported barriers related to four broad areas: (1) organisational and structural, (2) access and engagement, (3) treatment and service delivery, and (4) training and resources. Survey data supported the barriers identified in the qualitative findings.This research highlights significant gaps in the response of MH and AOD services to refugee youth with comorbidity. Based on the findings, ways of overcoming the barriers are discussed, and are of particular relevance to policy makers, organisations and clinicians.Miriam Posselt, Karalyn McDonald, Nicholas Procter, Charlotte de Crespigny and Cherrie Galletl

    Molecular Characterisation of Bacterial Wilt Resistance in \u3cem\u3eLolium Multiflorum\u3c/em\u3e Lam.

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    Italian ryegrass (Lolium multiflorum Lam.), a forage grass of prime importance throughout the world, is adversely affected by the pathogen Xanthomonas translucens pv graminis. Breeding for resistant cultivars is the only practicable means of disease control. However, the inheritance of bacterial wilt resistance is largely unknown. The aim of our research is to elucidate genetic control of bacterial wilt resistance using molecular technologies such as genetic linkage mapping and the analysis of quantitative trait loci (QTL)

    Genetic mapping reveals a single major QTL for bacterial wilt resistance in Italian ryegrass (Lolium multiflorum Lam.)

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    Bacterial wilt caused by Xanthomonas translucens pv. graminis (Xtg) is a major disease of economically important forage crops such as ryegrasses and fescues. Targeted breeding based on seedling inoculation has resulted in cultivars with considerable levels of resistance. However, the mechanisms of inheritance of resistance are poorly understood and further breeding progress is difficult to obtain. This study aimed to assess the relevance of the seedling screening in the glasshouse for adult plant resistance in the field and to investigate genetic control of resistance to bacterial wilt in Italian ryegrass (Lolium multiflorum Lam.). A mapping population consisting of 306 F1 individuals was established and resistance to bacterial wilt was assessed in glasshouse and field experiments. Highly correlated data (r = 0.67–0.77, P < 0.01) between trial locations demonstrated the suitability of glasshouse screens for phenotypic selection. Analysis of quantitative trait loci (QTL) based on a high density genetic linkage map consisting of 368 amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) markers revealed a single major QTL on linkage group (LG) 4 explaining 67% of the total phenotypic variance (Vp). In addition, a minor QTL was observed on LG 5. Field experiments confirmed the major QTL on LG 4 to explain 43% (in 2004) to 84% (in 2005) of Vp and also revealed additional minor QTLs on LG 1, LG 4 and LG 6. The identified QTLs and the closely linked markers represent important targets for marker-assisted selection of Italian ryegrass

    Technical Performance and Energy Intensity of the Electrode-Separator Composite Manufacturing Process

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    AbstractEnergy storage is one of the key technological factors that determine the success of a sustainable future. Especially green mobility concepts for electric or hybrid electric vehicles highly depend upon storage technologies with high energy density and light-weight materials. At the same time, innovative production processes should be conceived that ensure energy and resource efficient manufacturing of these energy storage devices. This paper focuses on the technical as well as dynamic energetic performance analysis and evaluation of an innovative electrode-separator composite manufacturing process of lithium-ion batteries for automotive applications. The technical performance indicators such as battery capacity and the energy intensity of the manufacturing process are highly dependent upon process parameters, machine and product design. Hence, in-depth process knowledge must be acquired to understand interdependencies between all system components. Thus, the manufacturing process is analysed in terms of its dynamics, and correlations between process parameters, process energy demand and final product properties are assessed. The resulting knowledge is important for the subsequent design of large-scale products and processes involved design, as well as for characterisation of the manufacturing process for life cycle inventory databases or life cycle costing calculations

    Analytical treatment of the resolution function for small-angle scattering

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    A multi-wavelength study of a double intermediate-mass protostar - from large-scale structure to collimated jets

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    (abridged) We study a previously discovered protostellar source that is deeply embedded and drives an energetic molecular outflow. The source, UYSO1, is located close to IRAS 07029-1215 at a distance of ~1 kpc. The multi-wavelength observations resulted in the detection of a double intermediate-mass protostar at the location of UYSO1. In addition to the associated molecular outflow, with a projected size of 0.25 pc, two intersecting near-infrared jets with projected sizes of 0.4 pc and 0.2 pc were found. However, no infrared counterparts to the driving sources could be detected in sensitive near- to far-infrared observations. In interferometric millimeter observations, UYSO1 was resolved into two continuum sources with high column densities and gas masses of 3.5 Mo and 1.2 Mo, with a linear separation of 4200 AU. We report the discovery of a H2O maser toward one of the two sources. The total luminosity is roughly estimated to be ~50 Lo, shared by the two components, one of which is driving the molecular outflow that has a dynamical timescale of less than a few thousand years. The jets of the two individual components are not aligned. Submillimeter observations show that the region lacks typical hot-core chemistry. We thus find two protostellar objects, whose associated circumstellar and parent core masses are high enough to suggest that they may evolve into intermediate-mass stars. This is corroborated by their association with a very massive and energetic CO outflow, suggesting high protostellar accretion rates. The short dynamical timescale of the outflow, the pristine chemical composition of the cloud core and absence of hot core tracers, the absence of detectable radio continuum emission, and the very low protostellar luminosity argue for an extremely early evolutionary stage.Comment: 10 pages, 10 figures, accepted for publication in A&A; minor changes: typos corrected, revised argument in Section

    Simultaneous X-ray, radio, near-infrared, and optical monitoring of Young Stellar Objects in the Coronet cluster

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    Multi-wavelength (X-ray to radio) monitoring of Young Stellar Objects (YSOs) can provide important information about physical processes at the stellar surface, in the stellar corona, and/or in the inner circumstellar disk regions. While coronal processes should mainly cause variations in the X-ray and radio bands, accretion processes may be traced by time-correlated variability in the X-ray and optical/infrared bands. Several multi-wavelength studies have been successfully performed for field stars and approx. 1-10 Myr old T Tauri stars, but so far no such study succeeded in detecting simultaneous X-ray to radio variability in extremely young objects like class I and class 0 protostars. Here we present the first simultaneous X-ray, radio, near-infrared, and optical monitoring of YSOs, targeting the Coronet cluster in the Corona Australis star-forming region, which harbors at least one class 0 protostar, several class I objects, numerous T Tauri stars, and a few Herbig AeBe stars. [...] Seven objects are detected simultaneously in the X-ray, radio, and optical/infrared bands; they constitute our core sample. While most of these sources exhibit clear variability in the X-ray regime and several also display optical/infrared variability, none of them shows significant radio variability on the timescales probed. We also do not find any case of clearly time-correlated optical/infrared and X-ray variability. [...] The absence of time-correlated multi-wavelength variability suggests that there is no direct link between the X-ray and optical/infrared emission and supports the notion that accretion is not an important source for the X-ray emission of these YSOs. No significant radio variability was found on timescales of days.Comment: 11 pages, 11 figures, accepted for publication in A&A (06 Dec 2006
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