6,789 research outputs found

    Performance and selection of winter durum wheat genotypes in different European conventional and organic fields

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    Sustainability is a key factor for the future of agriculture. Productivity in agriculture has more than tripled in developed countries since the 1950s. Beyond the success of plant breeding, the increased use of inorganic fertilizers, application of pesticides, and spread of irrigation also contributed to this success. However, impressive yield increases started to decline in the 1980s because of the lack of sustainability. One of the most beneficial ways to increase sustainability is organic agriculture. In such agro-ecosystem-based holistic production systems the prerequisite of successful farming is the availability of crop genotypes that perform well. However, selection of winter durum wheat for sub-optimal growing conditions is still mainly neglected, and the organic seed market also lacks of information on credibly tested winter durum varieties suitable for organic agriculture

    Indication for Ļ€+Ļ€āˆ’\pi^+ \pi^- scattering in p+pp+p collisions at sNN=\sqrt{s_{_{NN}}} = 200 GeV

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    A Ļ(770)0\rho(770)^0 mass shift of about -40 MeV/c2c^2 was measured in p+pp+p collisions at sNN=\sqrt{s_{_{NN}}} = 200 GeV at RHIC. Previous mass shifts have been observed at CERN-LEBC-EHS and CERN-LEP. We will show that phase space does not account for the Ļ(770)0\rho(770)^0 mass shift measured at RHIC, CERN-LEBC-EHS and CERN-LEP and conclude that there are significant scattering interactions in p+pp+p collisions.Comment: 11 pages and 7 figure

    "It's a revolving door": Ego-depletion among prisoners with injecting drug use histories as a barrier to post-release success

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    Background: People who inject drugs (PWID) are overrepresented among prisoner populations worldwide. This qualitative study used the psychological concept of ā€œego-depletionā€ as an exploratory framework to better understand the disproportionate rates of reincarceration among people with injecting drug use histories. The aim was to illuminate mechanisms by which prospects for positive post-release outcomes for PWID are enhanced or constricted. Methods: Participants were recruited from a longitudinal cohort study, SuperMIX, in Victoria, Australia. Eligible participants were invited to participate in an in-depth interview. Inclusion criteria were: aged 18+; lifetime history of injecting drug use; incarcerated for >three months and released from custody <12 months previously. Analysis of 48 interviews examined how concepts relevant to the ego-depletion framework (self-regulation; standards; consequences and mitigators of ego-depletion) manifested in participantsā€™ narratives. Results: Predominantly, participants aimed to avoid a return to problematic drug use and recidivism, and engaged in effortful self-regulation to pursue their post-release goals. Post-release environments were found to diminish self-regulation resources, leading to states of ego-depletion and compromising the capacity to self-regulate according to their ideals. Fatalism, stress, and fatigue associated with the transition period exacerbated ego-depletion. Strategies that mitigated ego-depletion included avoidance of triggering environments; reducing stress through opioid agonist therapy; and fostering positive affect through supportive relationships. Conclusions: Post-release environments are ego-depleting and inconducive to sustaining behavioural changes for PWID leaving prison. Correctionsā€™ behaviourist paradigms take insufficient account of the socio-structural factors impacting on an individual's self-regulation capacities in the context of drug dependence and desistance processes. Breaking the cycles of reincarceration among PWID requires new approaches that moderate ego-depletion and facilitate long-term goal-pursuit

    Structural competency in the post-prison period for people who inject drugs: A qualitative case study

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    Introduction: Access to services is key to successful community (re-)integration following release from prison. But many people experience disengagement from services, including people who inject drugs (PWID). We use a case study approach and the notion of structural competency to examine influences on access to services among a group of PWID recently released from prison. Methods: This qualitative study recruited participants from SuperMIX, (a longitudinal cohort study in Victoria, Australia). Inclusion criteria: aged 18+; lifetime history of injecting drug use; incarcerated for > three months and released from custody < 12 months previously. From 48 participants, five case studies were selected as emblematic of the complex and intersecting factors occurring at the time participants missed an appointment at a service. Results: Numerous, concurrent, and interdependent structural influences in participantsā€™ lives coincided with their difficulty accessing and maintaining contact with services and resulted in missed appointments. The key factors involved in the cases presented here include policies around opioid agonist treatment, inadequate, unsuitable and unsafe housing, the management of mental health and side effects of treatment, the lack of social support or estrangement from family, and economic hardship. The support available from service workers to navigate these structural issues was inconsistent. One dissenting case is examined in which missing appointments is anticipated and accommodated. Conclusions: A case study approach enabled a holistic and in-depth examination of upstream structural elements that intersect with limited social and economic resources to exacerbate the challenges of community re-entry. These results highlight structural issues that have a disproportionate impact on the choices and opportunities for PWID. The incorporation of a structural competency framework in design of services and in staff training could support person-centred and coordinated service provision that take into account PWID's experiences post-release to overcome structural barriers to service engagement

    Replica theory for learning curves for Gaussian processes on random graphs

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    Statistical physics approaches can be used to derive accurate predictions for the performance of inference methods learning from potentially noisy data, as quantified by the learning curve defined as the average error versus number of training examples. We analyse a challenging problem in the area of non-parametric inference where an effectively infinite number of parameters has to be learned, specifically Gaussian process regression. When the inputs are vertices on a random graph and the outputs noisy function values, we show that replica techniques can be used to obtain exact performance predictions in the limit of large graphs. The covariance of the Gaussian process prior is defined by a random walk kernel, the discrete analogue of squared exponential kernels on continuous spaces. Conventionally this kernel is normalised only globally, so that the prior variance can differ between vertices; as a more principled alternative we consider local normalisation, where the prior variance is uniform

    Probabilistic models of information retrieval based on measuring the divergence from randomness

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    We introduce and create a framework for deriving probabilistic models of Information Retrieval. The models are nonparametric models of IR obtained in the language model approach. We derive term-weighting models by measuring the divergence of the actual term distribution from that obtained under a random process. Among the random processes we study the binomial distribution and Bose--Einstein statistics. We define two types of term frequency normalization for tuning term weights in the document--query matching process. The first normalization assumes that documents have the same length and measures the information gain with the observed term once it has been accepted as a good descriptor of the observed document. The second normalization is related to the document length and to other statistics. These two normalization methods are applied to the basic models in succession to obtain weighting formulae. Results show that our framework produces different nonparametric models forming baseline alternatives to the standard tf-idf model
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