65 research outputs found

    Biological Principles in Self-Organization of Young Brain - Viewed from Kohonen Model

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    Variants of the Kohonen model are proposed to study biological principles of self-organization in a model of young brain. We suggest a function to measure aquired knowledge and use it to auto-adapt the topology of neuronal connectivity, yielding substantial organizational improvement relative to the standard model. In the early phase of organization with most intense learning, we observe that neural connectivity is of Small World type, which is very efficient to organize neurons in response to stimuli. In analogy to human brain where pruning of neural connectivity (and neuron cell death) occurs in early life, this feature is present also in our model, which is found to stabilize neuronal response to stimuli

    Automatic Detection of Expanding HI Shells Using Artificial Neural Networks

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    The identification of expanding HI shells is difficult because of their variable morphological characteristics. The detection of HI bubbles on a global scale therefore never has been attempted. In this paper, an automatic detector for expanding HI shells is presented. The detection is based on the more stable dynamical characteristics of expanding shells and is performed in two stages. The first one is the recognition of the dynamical signature of an expanding bubble in the velocity spectra, based on the classification of an artificial neural network. The pixels associated with these recognized spectra are identified on each velocity channel. The second stage consists in looking for concentrations of those pixels that were firstly pointed out, and to decide if they are potential detections by morphological and 21-cm emission variation considerations. Two test bubbles are correctly detected and a potentially new case of shell that is visually very convincing is discovered. About 0.6% of the surveyed pixels are identified as part of a bubble. These may be false detections, but still constitute regions of space with high probability of finding an expanding shell. The subsequent search field is thus significantly reduced. We intend to conduct in the near future a large scale HI shells detection over the Perseus Arm using our detector.Comment: 39 pages, 11 figures, accepted by PAS

    Analysis of a master-slave architecture for distributed evolutionary computations

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    Attitudes and behaviour towards convenience food and food waste in the United Kingdom

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    Households in the UK discard much food. A reduction in such waste to mitigate environmental impact is part of UK government policy. This study investigated whether household food waste is linked to a lifestyle reliant on convenience food in younger consumers. A survey of 928 UK residents aged 18-40 years and responsible for the household food shopping (male n = 278; female n = 650) completed an online questionnaire designed to measure attitudes to convenience food and to quantify household food waste. Cluster analysis of 24 food-related lifestyle factors identified 5 consumer groups. General linear modelling techniques were used to test relationships between the purchase frequency of convenience food and household food waste. From the cluster analysis, five distinct convenience profiles emerged comprising: ‘epicures’ (n = 135), ‘traditional consumers’ (n = 255), ‘casual consumers’ (n = 246), ‘food detached consumers’ (n = 151) and ‘kitchen evaders’ (n = 141). Casual consumers and kitchen evaders were the most reliant on convenience food and notably were the most wasteful. The demographic profile of kitchen evaders matched the population groups currently targeted by UK food waste policy. Casual consumers represent a new and distinct group characterised by “buy a lot and waste a lot” behaviour. Household size, packaging format, price-awareness and marketing all appear to influence levels of food waste. However, it seems that subtle behavioural and sociocultural factors also have impact. Further research is needed to elucidate the factors that mediate the positive association between the purchase of convenience food and reported food waste in order to inform food waste policy and initiatives

    Value-Chain Wide Food Waste Management: A Systematic Literature Review

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    © 2019, Springer Nature Switzerland AG. The agriculture value chain, from farm to fork, has received enormous attention because of its key role in achieving United Nations Global Challenges Goals. Food waste occurs in many different forms and at all stages of the food value chain, it has become a worldwide issue that requires urgent actions. However, the management of food waste has been traditionally segmented and in an isolated manner. This paper reviews existing work that has been done on food waste management in literature by taking a holistic approach, in order to identify the causes of food waste, food waste prevention strategies, and elicit recommendations for future work. A five step systematic literature review has been adopted for a thorough examination of the existing research on the topic and new insights have been obtained. The findings suggest that the main sources of food waste include food overproduction and surplus, food waste caused by processing, logistical inconsistencies, and households. Main food waste prevention strategies have been revealed in this paper include policy solutions, packaging solutions, date-labelling solutions, logistics solutions, changing consumers’ behaviours, and reuse and redistribution solutions. Future research directions such as using value chain models to reduce food waste and forecasting food waste have been identified in this paper. This study makes a contribution to the extant literature in the field of food waste management by discovering main causes of food waste in the value chain and eliciting prevention strategies that can be used to reduce/eliminate relevant food waste

    Vascular and blood-brain barrier-related changes underlie stress responses and resilience in female mice and depression in human tissue

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    Prevalence, symptoms, and treatment of depression suggest that major depressive disorders (MDD) present sex differences. Social stress-induced neurovascular pathology is associated with depressive symptoms in male mice; however, this association is unclear in females. Here, we report that chronic social and subchronic variable stress promotes blood-brain barrier (BBB) alterations in mood-related brain regions of female mice. Targeted disruption of the BBB in the female prefrontal cortex (PFC) induces anxiety- and depression-like behaviours. By comparing the endothelium cell-specific transcriptomic profiling of the mouse male and female PFC, we identify several pathways and genes involved in maladaptive stress responses and resilience to stress. Furthermore, we confirm that the BBB in the PFC of stressed female mice is leaky. Then, we identify circulating vascular biomarkers of chronic stress, such as soluble E-selectin. Similar changes in circulating soluble E-selectin, BBB gene expression and morphology can be found in blood serum and postmortem brain samples from women diagnosed with MDD. Altogether, we propose that BBB dysfunction plays an important role in modulating stress responses in female mice and possibly MDD
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