1,995 research outputs found

    Agricultural production in Greater Sekhukhune: the future for food security in a poverty node of South Africa?

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    This paper argues that within the range of complementary activities necessary to secure the food security of marginalised groups in South Africa in places such as Greater Sekhukhune, the aspect of agricultural production is often neglected. A comprehensive approach to food security should focus on exploiting opportunities around increasing local food availability through production, as well as stimulating food accessibility by, for example, supporting small enterprises through micro-credit, and supporting food utilisation through education. In this way a range of options is created that vulnerable people can adopt to promote their livelihoods beyond survivalist strategies. This paper explores the issue of agricultural production within Greater Sekhukhune to provide insights into the challenges facing a comprehensive food security strategy that would guarantee food supply through a range of interventions. The study in the Greater Sekhukhune District in Limpopo Province was conducted through two sets of household surveys (2004 and 2006) and the responses to the agricultural production part of these surveys are discussed. Marked changes from 2004 to 2006 were observed. For “agrarian reform†to be a success, the necessary institutional framework needs to be in place to enable a broad range of services from government and non-governmental actors. The facilitation of such “joined up governmentâ€, although in existence in theory, requires concerted political will to become a reality.Food security, agricultural production, household surveys, Greater Sekhukhune, Agricultural and Food Policy, Consumer/Household Economics, Food Consumption/Nutrition/Food Safety, Food Security and Poverty,

    Emotional, cognitive and behavioral self-regulation in forensic psychiatric patients:Changes over time and associations with childhood trauma, identity and personality pathology

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    The construct of self-regulation is of particular interest to the forensic psychiatric practice due to its associations with both clinical and criminal outcomes, as well as recidivism. However, research on different components of self-regulation within forensic psychiatric practice is rare. The current study aimed to gain knowledge on the construct of self-regulation in a sample of forensic psychiatric patients (N = 94). Firstly, by investigating change of emotional, behavioral and cognitive self-regulation over the course of 12 months in state-mandated care in a treatment facility. Secondly, by looking at the associations between these three elements of self-regulation and childhood trauma, identity dysfunction and personality pathology. Repeated measures ANOVA showed little to no difference in average self-regulation over time (only for behavioral regulation), and rank-order stability was relatively high in most cases. Path analysis showed that: emotion regulation was associated with all outcomes; behavioral regulation with all except childhood trauma and detachment; and cognitive regulation only with antagonism and negative affectivity. Findings suggest short-term changes are unlikely and indicate relative importance of emotional, and to some extent behavioral regulation for clinical practice. However, due to sample size restrictions, interpretations should be made with caution

    Mechanical modulation of single-electron tunneling through molecular-assembled metallic nanoparticles

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    We present a microscopic study of single-electron tunneling in nanomechanical double-barrier tunneling junctions formed using a vibrating scanning nanoprobe and a metallic nanoparticle connected to a metallic substrate through a molecular bridge. We analyze the motion of single electrons on and off the nanoparticle through the tunneling current, the displacement current and the charging-induced electrostatic force on the vibrating nanoprobe. We demonstrate the mechanical single-electron turnstile effect by applying the theory to a gold nanoparticle connected to the gold substrate through alkane dithiol molecular bridge and probed by a vibrating platinum tip.Comment: Accepted by Phys. Rev.

    Barriers to EMS assimilation in the US, Australia, Hong Kong, Norway and Switzerland: A Cross regional comparison

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    Electronic Meeting Systems (EMS) have the capabilities to support group members in task collaboration. While there have been many case studies and lab experiments on how EMS can support group tasks, large scale macro investigations exploring EMS adoption and use have been practically non-existent. Furthermore, while several EMS assimilation barriers have been suggested, their validation across organizations remains unexplored. In this paper, we describe a global initiative to explore information technology support for task-oriented collaboration in the US, Australia, Hong Kong, Norway and Switzerland. We focus specifically on EMS and investigate their adoption, use and assimilation barriers in organizations across the five regions. Our results suggest that EMS adoption and use is limited across all the regions. A further investigation in EMS assimilation barriers suggests that these barriers differ across the regions and there is little agreement over how they are ranked. Implications of our findings are discussed for practitioners and researchers

    Stress impairs intentional memory control through altered theta oscillations in lateral parietal cortex

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    Accumulating evidence suggests that forgetting is not necessarily a passive process but that we can, to some extent, actively control what we remember and what we forget. Although this intentional control of memory has potentially far-reaching implications, the factors that influence our capacity to intentionally control our memory are largely unknown. Here, we tested whether acute stress may disrupt the intentional control of memory and, if so, through which neural mechanism. We exposed healthy men and women to a stress (n=27) or control (n=26) procedure before they aimed repeatedly to retrieve some previously learned cue-target pairs and to actively suppress others. While control participants showed reduced memory for supressed compared to baseline pairs in a subsequent memory test, this suppression-induced forgetting was completely abolished after stress. Using magnetoencephalography (MEG), we show that the reduced ability to suppress memories after stress is associated with altered theta activity in the inferior temporal cortex when the control process (retrieval or suppression) is triggered and in the lateral parietal cortex when control is exerted, with the latter being directly correlated with the stress hormone cortisol. Moreover, the suppression-induced forgetting was linked to altered connectivity between the hippocampus and right dorsolateral prefrontal cortex, which in turn was negatively correlated to stress-induced cortisol increases. These findings provide novel insights into conditions under which our capacity to actively control our memory breaks down and may have considerable implications for stress-related psychopathologies, such as posttraumatic stress disorder, that are characterized by unwanted memories of distressing events.Significance Statement: It is typically assumed that forgetting is a passive process that can hardly be controlled. There is, however, evidence that we may actively control, to some extent, what we remember and what we forget. This intentional memory control has considerable implications for mental disorders in which patients suffer from unwanted (e.g., traumatic) memories. Here, we demonstrate that the capacity to intentionally control our memory breaks down after stress. Using magnetoencephalography, we show that this stress-induced memory control deficit is linked to altered activity in the lateral parietal cortex and the connectivity between the hippocampus and right prefrontal cortex. These findings provide novel insights into conditions under which memory control fails and are highly relevant in the context of stress-related psychopathologies

    Pupil-linked Phasic Arousal Predicts a Reduction of Choice Bias Across Species and Decision Domains

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    Decisions are often made by accumulating ambiguous evidence over time. The brain's arousal systems are activated during such decisions. In previous work in humans, we found that evoked responses of arousal systems during decisions are reported by rapid dilations of the pupil and track a suppression of biases in the accumulation of decision-relevant evidence (de Gee et al., 2017). Here, we show that this arousal-related suppression in decision bias acts on both conservative and liberal biases, and generalizes from humans to mice, and from perceptual to memory-based decisions. In challenging sound-detection tasks, the impact of spontaneous or experimentally induced choice biases was reduced under high phasic arousal. Similar bias suppression occurred when evidence was drawn from memory. All of these behavioral effects were explained by reduced evidence accumulation biases. Our results point to a general principle of interplay between phasic arousal and decision-making

    Perturbation of Tunneling Processes by Mechanical Degrees of Freedom in Mesoscopic Junctions

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    We investigate the perturbation in the tunneling current caused by non-adiabatic mechanical motion in a mesoscopic tunnel junction. A theory introduced by Caroli et al. \cite{bi1,bi2,bi3} is used to evaluate second order self-energy corrections for this non-equilibrium situation lacking translational invariance. Inelastic signatures of the mechanical degrees of freedom are found in the current-voltage I(V)I(V) characteristics. These give rise to sharp features in the derivative spectrum, d2I/dV2d^2I/dV^2.Comment: 22 pages LaTeX + 3 uuencoded PS picture

    A Cluster-Matching-Based Method for Video Face Recognition

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    Face recognition systems are present in many modern solutions and thousands of applications in our daily lives. However, current solutions are not easily scalable, especially when it comes to the addition of new targeted people. We propose a cluster-matching-based approach for face recognition in video. In our approach, we use unsupervised learning to cluster the faces present in both the dataset and targeted videos selected for face recognition. Moreover, we design a cluster matching heuristic to associate clusters in both sets that is also capable of identifying when a face belongs to a non-registered person. Our method has achieved a recall of 99.435% and a precision of 99.131% in the task of video face recognition. Besides performing face recognition, it can also be used to determine the video segments where each person is present.Comment: 13 page
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