3,113 research outputs found

    Soil Organic Matter Fractions and Aggregate Distribution in Response to Tall Fescue Stands

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    The study was conducted to evaluate the influences of tall fescue management on soil organic matter fractions and macro- and microaggregate distribution. Soil samples were collected from four paired adjacent fields consisting of five years of tall fescue mono and poly stands in Western Kentucky. Soil samples from 0 to 15 cm and 15 to 30 cm soil depths were analyzed for soil organic C and N, particulate organic matter C (POM-C) and N (POM-N), macro- and micro aggregate distribution and C-associated with macro- and micro- aggregates. Significant effects were observed between stands for all the properties, except total C, microaggregates and C-associated with microaggregates. Sampling depth significantly influenced total C and N in both stands. Particulate organic matter C and N and C-associated with macroaggregates and the amount of macroaggregates were strongly affected by tall fescue management. This confirmed the hypothesis that early changes in soil properties were reflected in labile C and N fractions and soil structure. Tall fescue mixture stands had 44% higher POM-C, 50% higher POM-N, 26% more macroaggregates and 33% more C-associated with macroaggregates compared to the tall fescue mono stands at the soil surface of 0 to 15 cm

    Soil Organic Matter Fractions and Aggregate Distribution in Response to Tall Fescue Stands

    Get PDF
    The study was conducted to evaluate the influences of tall fescue management on soil organic matter fractions and macro- and microaggregate distribution. Soil samples were collected from four paired adjacent fields consisting of five years of tall fescue mono and poly stands in Western Kentucky. Soil samples from 0 to 15 cm and 15 to 30 cm soil depths were analyzed for soil organic C and N, particulate organic matter C (POM-C) and N (POM-N), macro- and micro aggregate distribution and C-associated with macro- and micro- aggregates. Significant effects were observed between stands for all the properties, except total C, microaggregates and C-associated with microaggregates. Sampling depth significantly influenced total C and N in both stands. Particulate organic matter C and N and C-associated with macroaggregates and the amount of macroaggregates were strongly affected by tall fescue management. This confirmed the hypothesis that early changes in soil properties were reflected in labile C and N fractions and soil structure. Tall fescue mixture stands had 44% higher POM-C, 50% higher POM-N, 26% more macroaggregates and 33% more C-associated with macroaggregates compared to the tall fescue mono stands at the soil surface of 0 to 15 cm

    Effective surface motion on a reactive cylinder of particles that perform intermittent bulk diffusion

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    In many biological and small scale technological applications particles may transiently bind to a cylindrical surface. In between two binding events the particles diffuse in the bulk, thus producing an effective translation on the cylinder surface. We here derive the effective motion on the surface, allowing for additional diffusion on the cylinder surface itself. We find explicit solutions for the number of adsorbed particles at one given instant, the effective surface displacement, as well as the surface propagator. In particular sub- and superdiffusive regimes are found, as well as an effective stalling of diffusion visible as a plateau in the mean squared displacement. We also investigate the corresponding first passage and first return problems.Comment: 26 pages, 5 figure

    Who is in the transition gap? Transition from CAMHS to AMHS in the Republic of Ireland

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    Objective: The ITRACK study explored the process and predictors of transition between Child and Adolescent Mental Health Services (CAMHS) and Adult Mental Health Services (AMHS) in the Republic of Ireland. Method: Following ethical approval, clinicians in each of Ireland's four Health Service Executive (HSE) areas were contacted, informed about the study and invited to participate. Clinicians identified all cases who had reached the transition boundary (i.e. upper age limit for that CAMHS team ) between January and December 2010. Data were collected on clinical and socio-demographic details and factors that informed the decision to refer or not refer to AMHS and case notes were scrutinised to ascertain the extent of information exchanged between services during transition

    Understanding the relationship between experiencing workplace cyberbullying, employee mental strain and job satisfaction: a dysempowerment approach

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    Although the literature on traditional workplace bullying is advancing rapidly, currently investigations addressing workplace cyberbullying are sparse. To counter this, we present three connected research studies framed within dysempowerment theory (Kane, K., & Montgomery, K. (1998). A framework for understanding dysempowerment in organizations. Human Resource Management, 37, 263–275.) which examine the relationship between volume and intensity of cyberbullying experience and individual mental strain and job satisfaction; whether the impact is more negative as compared to traditional bullying; and whether state negative affectivity (NA) and interpersonal justice mediate the relationship. Additionally, we also considered the impact of witnessing cyberbullying acts on individual outcomes. A total sample comprised 331 UK university employees across academic, administrative, research, management and technical roles. Overall, significant relationships between cyberbullying exposure and outcomes emerged, with cyberbullying exposure displaying a stronger negative relationship with job satisfaction when compared to offline bullying. Analysis supported an indirect effect between cyberbullying acts and outcomes via NA and between cyberbullying acts and job satisfaction via interpersonal justice. No support for a serial multiple mediation model of experiencing cyberbullying to justice to NA to outcome was found. Further, perceived intensity of cyberbullying acts and witnessing cyberbullying acts did not significantly relate to negative outcomes. Theoretical and practical implications of the research are discussed

    A Search for Intrinsic Polarization in O Stars with Variable Winds

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    New observations of 9 of the brightest northern O stars have been made with the Breger polarimeter on the 0.9~m telescope at McDonald Observatory and the AnyPol polarimeter on the 0.4~m telescope at Limber Observatory, using the Johnson-Cousins UBVRI broadband filter system. Comparison with earlier measurements shows no clearly defined long-term polarization variability. For all 9 stars the wavelength dependence of the degree of polarization in the optical range can be fit by a normal interstellar polarization law. The polarization position angles are practically constant with wavelength and are consistent with those of neighboring stars. Thus the simplest conclusion is that the polarization of all the program stars is primarily interstellar. The O stars chosen for this study are generally known from ultraviolet and optical spectroscopy to have substantial mass loss rates and variable winds, as well as occasional circumstellar emission. Their lack of intrinsic polarization in comparison with the similar Be stars may be explained by the dominance of radiation as a wind driving force due to higher luminosity, which results in lower density and less rotational flattening in the electron scattering inner envelopes where the polarization is produced. However, time series of polarization measurements taken simultaneously with H-alpha and UV spectroscopy during several coordinated multiwavelength campaigns suggest two cases of possible small-amplitude, periodic short-term polarization variability, and therefore intrinsic polarization, which may be correlated with the more widely recognized spectroscopic variations.Comment: LaTeX2e, 22 pages including 11 tables; 12 separate gif figures; uses aastex.cls preprint package; accepted by The Astronomical Journa

    Environmental risk assessment of genetically modified crops: The use of molecular markers to trace insect and wind dispersal of Brassica napus pollen.

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    End of Project ReportThis project aimed to develop a better understanding of the potential risks of gene flow and to generate isolation distances required for genetically modified (GM) OSR. The study examined biotic (insect) and abiotic (wind) pollen dispersal over two seasons. A considerable portion of work was devoted to the development of molecular markers, to differentiate Brassica napus varieties from each other to distinguish them from their wild relatives. The project broadly aimed to study gene flow, via pollen movement, from OSR but specifically aimed to: ! Characterise B. napus cv. Marinka using molecular markers. ! Elucidate the distance travelled by OSR pollen by biotic dispersal. ! Elucidate the distance travelled by OSR pollen by abiotic dispersal. ! Elucidate pollination/seed set at various distances from a source crop using male sterile bait plants. ! Develop risk assessment/containment strategies

    Bulk-mediated surface diffusion on a cylinder: propagators and crossovers

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    We consider the effective surface motion of a particle that freely diffuses in the bulk and intermittently binds to that surface. From an exact approach we derive various regimes of the effective surface motion characterized by physical rates for binding/unbinding and the bulk diffusivity. We obtain a transient regime of superdiffusion and, in particular, a saturation regime characteristic for the cylindrical geometry. This saturation, however, in a finite system is not terminal but eventually turns over to normal surface diffusion. The first passage behavior of particles to the cylinder surface is derived. Consequences for actual systems are discussed.Comment: 4 pages REVTeX4, 2 figure

    Exploring social identity change during mental healthcare transition

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    Adolescents attending Child & Adolescent Mental Health Services (CAMHS) requiring ongoing care are transferred to adult services (AMHS) at eighteen. Many young people with service needs are not being referred, or are refusing referral to AMHS. This study explored these issues from a social identity change perspective. Transcripts of interviews conducted with young people (n=11), their parents (n=5) and child (n=11) and adult (n=8) psychiatrists were thematically analysed. Transition to AMHS confirmed an ill ness identity. Young people adopting this identity saw continued service engagement as identity-congruent. Disengagement was attributed to failure to adopt an illness identity or to an emerging adult identity associated with greater independence. Fractious professional relationships hindered transition and delayed the formation of a therapeutic alliance with AMHS staff. Disengagement post-transfer was linked to incompatibility between the AMHS service remit and specific illness identities. This study demonstrates how an intersection between identities shapes service engagement and disengagement
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