543 research outputs found

    Relationships Between Delinquency and Substance Use Among Adolescents Emancipating from Foster Care

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    Adolescents emancipating from foster care exhibit high rates of both delinquency and substance use, although it is less clear how these behaviors relate to one another. We aimed to examine the reciprocal relationships between these risk behaviors while accounting for relevant child welfare factors. We use data from the Multi-Site Evaluation of Foster Youth Programs to explore longitudinal associations between delinquent behaviors and substance use (tobacco, alcohol, and marijuana) among youths ages 17 and 18 (N = 429). Delinquency at age 17 was a positive predictor of substance use at age 18, after controlling for baseline use of substances. In contrast, substance use at age 17 was not predictive of increased delinquency at age 18 after baseline delinquency was controlled. Findings indicate that among youths emancipating from the foster care system, delinquent behavior might increase vulnerability for future substance use, as opposed to the latter

    Aphid Feeding Behavior: Relationship to Barley Yellow Dwarf Virus Resistance in \u3ci\u3eAgropyron\u3c/i\u3e Species

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    The infectibility of various Agropyron species (wheatgrasses) was examined with respect to three isotates of barley yellow dwarf virus (BYDV) by infesting them with appropriate vector aphids, followed by testing by enzyme-linked immunosorbent assay. Feeding behavior of the vetors Rhopalosiphum padi and Sitobion avenae was also electronically monitored to determine their ability to inoculate phloem. The results indicated that resistance to BYDV infection occurs in several Agropyron species. For most species tested. resistance seemed due to failure in virus increase. but in some species a major constraint on infection \\\u27as the inability of vectors to locate phloem. Two potential approaches to breeding for reduced BYDV in wheat by crossing with Agropyron species may thus be: incorporating factors reducing or preventing virus production and incorporating factors reducing the ability of vectors to inoculate plants successfully

    Evaluation of microbial communities associated with the liquid and solid phases of the rumen of cattle offered a diet of perennial ryegrass or white clover

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    Rumen microbiota plays an important role in animal productivity, methane production and health. Several different locations have been used to obtain rumen samples (i.e., liquid-phase samples, solid-phase samples, buccal swabs) in previous studies. Here we assess differences in the rumen microbiota between solid- and liquid-phases of the rumen under differing dietary conditions (white clover vs. perennial ryegrass); there were 4 sample types: liquid-associated/grass (LG), solid-associated/grass (SG), liquid-associated/clover (LC), and solid-associated/clover (SC). Four Holstein-Friesian cows were strip grazed on pure stands of perennial ryegrass or white clover in a change-over design experiment with 3 periods (each lasting for 3 weeks). Solid- and liquid- phase microbes were obtained following total rumen evacuation on the penultimate day of each period. DNA was extracted and multiplexed libraries sequenced using 16S next generation sequencing (Illumina MiSeq). Demultiplexed sequences underwent quality control and taxonomic profiles were generated for each sample. Statistical analysis for the effects of diet and phase was conducted both overall [using non-metric multidimensional scaling (NMDS) and diversity indices] and for individual taxa. Separation of both diet and phase was observed NMDS, with significant effects of diet (P < 0.001) and phase (P < 0.001) being observed. Regardless of diet, Prevotella was most abundant in the liquid samples. When assessing differences between phases, the majority of statistically significant taxa (predominantly from Archaea and the order Clostridiales) were found at higher relative abundances in solid-phase samples. Diversity (Shannon Index) was lower in the liquid-phase samples, possibly because of the higher relative abundance of Prevotella. A presence vs. absence approach, followed by Chi-squared testing, was adopted. Differences between phases (LG vs. LC, LC vs. LG, SG vs. SC, and SC vs. SG) and differences between phases for the clover diet (LC vs. SC and SC vs. LC) were significant (P < 0.001); differences between phases for the grass diet were non-significant. Sampling technique has a profound impact on reported microbial communities, which must be taken into consideration, particularly as archaea may be underestimated in the liquid-phase.</p

    Links between the rumen microbiota, methane emissions and feed efficiency of finishing steers offered dietary lipid and nitrate supplementation

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    peer-reviewedRuminant methane production is a significant energy loss to the animal and major contributor to global greenhouse gas emissions. However, it also seems necessary for effective rumen function, so studies of anti-methanogenic treatments must also consider implications for feed efficiency. Between-animal variation in feed efficiency represents an alternative approach to reducing overall methane emissions intensity. Here we assess the effects of dietary additives designed to reduce methane emissions on the rumen microbiota, and explore relationships with feed efficiency within dietary treatment groups. Seventy-nine finishing steers were offered one of four diets (a forage/concentrate mixture supplemented with nitrate (NIT), lipid (MDDG) or a combination (COMB) compared to the control (CTL)). Rumen fluid samples were collected at the end of a 56 d feed efficiency measurement period. DNA was extracted, multiplexed 16s rRNA libraries sequenced (Illumina MiSeq) and taxonomic profiles were generated. The effect of dietary treatments and feed efficiency (within treatment groups) was conducted both overall (using non-metric multidimensional scaling (NMDS) and diversity indexes) and for individual taxa. Diet affected overall microbial populations but no overall difference in beta-diversity was observed. The relative abundance of Methanobacteriales (Methanobrevibacter and Methanosphaera) increased in MDDG relative to CTL, whilst VadinCA11 (Methanomassiliicoccales) was decreased. Trimethylamine precursors from rapeseed meal (only present in CTL) probably explain the differences in relative abundance of Methanomassiliicoccales. There were no differences in Shannon indexes between nominal low or high feed efficiency groups (expressed as feed conversion ratio or residual feed intake) within treatment groups. Relationships between the relative abundance of individual taxa and feed efficiency measures were observed, but were not consistent across dietary treatments

    Assessing the farm-scale impacts of cover crops and non-inversion tillage regimes on nutrient losses from an arable catchment

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    The efficacy of cover crops and non-inversion tillage regimes at minimising farm-scale nutrient losses were assessed across a large, commercial arable farm in Norfolk, UK. The trial area, covering 143 ha, was split into three blocks: winter fallow with mouldboard ploughing (Block J); shallow non-inversion tillage with a winter oilseed radish (Raphanus sativus) cover crop (Block P); and direct drilling with a winter oilseed radish cover crop (Block L). Soil, water and vegetation chemistry across the trial area were monitored over the 2012/13 (pre-trial), 2013/14 (cover crops and non-inversion tillage) and 2014/15 (non-inversion tillage only) farm years. Results revealed oilseed radish reduced nitrate (NO3¬¬-N) leaching losses in soil water by 75–97% relative to the fallow block, but had no impact upon phosphorus (P) losses. Corresponding reductions in riverine NO3¬¬-N concentrations were not observed, despite the trial area covering 20% of the catchment. Mean soil NO3¬¬-N concentrations were reduced by ~77% at 60–90 cm depth beneath the cover crop, highlighting the ability of deep rooting oilseed radish to scavenge nutrients from deep within the soil profile. Alone, direct drilling and shallow non-inversion tillage were ineffective at reducing soil water NO3¬¬-N and P concentrations relative to conventional ploughing. Applying starter fertiliser to the cover crop increased radish biomass and nitrogen (N) uptake, but resulted in net N accumulation within the soil. There was negligible difference between the gross margins of direct drilling (£731 ha-1) and shallow non-inversion tillage (£758 ha-1) with a cover crop and conventional ploughing with fallow (£745 ha-1), demonstrating farm productivity can be maintained whilst mitigating diffuse pollution. The results presented here support the wider adoption of winter oilseed radish cover crops to reduce NO3¬¬-N leaching losses in arable systems, but caution that it may take several years before catchment-scale impacts downstream are detected

    The HIPASS survey of the Galactic plane in Radio Recombination Lines

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    We present a Radio Recombination Line (RRL) survey of the Galactic Plane from the HI Parkes All-sky Survey and associated Zone of Avoidance survey, which mapped the region l=196degr -- 0degr --52degr and |b| < 5degr at 1.4 GHz and 14.4 arcmin resolution. We combine three RRLs, H168α\alpha, H167α\alpha, and H166α\alpha to derive fully sampled maps of the diffuse ionized emission along the inner Galactic plane. The velocity information, at a resolution of 20 km/s, allows us to study the spatial distribution of the ionized gas and compare it with that of the molecular gas, as traced by CO. The longitude-velocity diagram shows that the RRL emission is mostly associated with CO gas from the molecular ring and is concentrated within the inner 30degr of longitude. A map of the free-free emission in this region of the Galaxy is derived from the line-integrated RRL emission, assuming an electron temperature gradient with Galactocentric radius of 496±100496\pm100 K/kpc. Based on the thermal continuum map we extracted a catalogue of 317 compact (<15 arcmin) sources, with flux densities, sizes and velocities. We report the first RRL observations of the southern ionized lobe in the Galactic centre. The line profiles and velocities suggest that this degree-scale structure is in rotation. We also present new evidence of diffuse ionized gas in the 3-kpc arm. Helium and carbon RRLs are detected in this survey. The He line is mostly observed towards HII regions, whereas the C line is also detected further away from the source of ionization. These data represent the first observations of diffuse C RRLs in the Galactic plane at a frequency of 1.4 GHz.Comment: 20 pages, 14 figures. MNRAS accepte

    Application of high-resolution telemetered sensor technology to develop conceptual models of catchment hydrogeological processes

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    Mitigating agricultural water pollution requires changes in land management practices and the implementation of on-farm measures to tackle the principal reasons for water quality failure. However, a paucity of robust empirical evidence on the hydrological functioning of river catchments can be a major constraint on the design of effective pollution mitigation strategies at the catchment-scale. In this regard, in 2010 the UK government established the Demonstration Test Catchment (DTC) initiative to evaluate the extent to which on-farm mitigation measures can cost-effectively reduce the impacts of agricultural water pollution on river ecology while maintaining food production capacity. A central component of the DTC platform has been the establishment of a comprehensive network of automated, web-based sensor technologies to generate high-temporal resolution empirical datasets of surface water, soil water, groundwater and meteorological parameters. In this paper, we demonstrate how this high-resolution telemetry can be used to improve our understanding of hydrological functioning and the dynamics of pollutant mobilisation and transport under a range of hydrometerological and hydrogeological conditions. Furthermore, we demonstrate how these data can be used to develop conceptual models of catchment hydrogeological processes and consider the implications of variable hydrological functioning on the performance of land management changes aimed at reducing agricultural water pollution

    Spectral and morphological analysis of the remnant of Supernova 1987A with ALMA & ATCA

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    We present a comprehensive spectral and morphological analysis of the remnant of Supernova (SN) 1987A with the Australia Telescope Compact Array (ATCA) and the Atacama Large Millimeter/submillimeter Array (ALMA). The non-thermal and thermal components of the radio emission are investigated in images from 94 to 672 GHz (λ\lambda 3.2 mm to 450 μ\mum), with the assistance of a high-resolution 44 GHz synchrotron template from the ATCA, and a dust template from ALMA observations at 672 GHz. An analysis of the emission distribution over the equatorial ring in images from 44 to 345 GHz highlights a gradual decrease of the east-to-west asymmetry ratio with frequency. We attribute this to the shorter synchrotron lifetime at high frequencies. Across the transition from radio to far infrared, both the synchrotron/dust-subtracted images and the spectral energy distribution (SED) suggest additional emission beside the main synchrotron component (Sνν0.73S_{\nu}\propto\nu^{-0.73}) and the thermal component originating from dust grains at T22T\sim22 K. This excess could be due to free-free flux or emission from grains of colder dust. However, a second flat-spectrum synchrotron component appears to better fit the SED, implying that the emission could be attributed to a pulsar wind nebula (PWN). The residual emission is mainly localised west of the SN site, as the spectral analysis yields 0.4α0.1-0.4\lesssim\alpha\lesssim-0.1 across the western regions, with α0\alpha\sim0 around the central region. If there is a PWN in the remnant interior, these data suggest that the pulsar may be offset westward from the SN position.Comment: ApJ accepted. 21 pages, emulateapj. References update
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