389 research outputs found

    Agent based approach to land use mix

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    Modelling and simulating the dynamics of crowd movement within the complex built environment such as a city centre is an evolutionary, processing research task. Recent methodological and theoretical advances have provided the opportunity to explore and provide answers to various crucial problems on land use mix. Daily in our urban settlements we seek for resources and attractions. Our search behaviour is complex and emergent, related to urban morphology and land use patterns as this is generated by our daily movement and activities. This report discusses a pedestrian movement study which examines the ways pedestrian behaviour and flows affect and are affected by the formation of the built environment and the land uses. The focus is in retailing uses and especially shopping. For the formulation of the model, an agent based simulation approach is adapted based on object oriented analysis and programming. Agents are given long distance vision and direct their movement and behaviour in response to the information retreat from their vision field, morphology of the local environment, and their individual desire for retail or exploration of the area. The simulations are used to extract meaningful conclusions on the pedestrian behaviour and factors that have an impact on it. Various formations of retail location patterns in a 7 x 7 grid are explored and three different approaches of agents’ behaviour are used in order to get meaningful conclusions

    CORRELATIONS BETWEEN PHYSICAL PROPERTIES AND POINT LOAD STRENGTH INDEX OF PRASINITES: A CASE STUDY FROM EAST ATTICA PREFECTURE

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    Ο σκοπός της παρούσας εργασίας είναι η διερεύνηση των στατιστικών συσχετίσεων μεταξύ του δείκτη αντοχής σημειακής φόρτισης και συγκεκριμένων φυσικών ιδιοτήτων, όπως της πυκνότητας και της ταχύτητας των διαμήκων υπερηχητικών κυμάτων σε ξηρή κατάσταση, για την περίπτωση των πρασινιτών (μεταβασίτες). Επιβεβαιώθηκαν, στατιστικά, σημαντικές συσχετίσεις μεταξύ των φυσικών ιδιοτήτων καθώς και μεταξύ εκάστης φυσικής ιδιότητας και του δείκτη αντοχής σημειακής φόρτισης. Σύμφωνα με την βιβλιογραφία, η εργασία αυτή αποτελεί μια πρώτη προσπάθεια ανάδειξης τέτοιων συσχετίσεων για τον συγκεκριμένο πετρολογικό τύπο, με αποτέλεσμα, οι εξισώσεις που προέκυψαν να αποτελούν χρήσιμο εργαλείο στην μελέτη αυτών των πετρολογικών τύπων τόσο στην περιοχή έρευνας, όσο και σε άλλες περιοχές όπου οι πρασινίτες, με παρόμοια δομικά χαρακτηριστικά, αποτελούν αντικείμενο μελέτης για τη θεμελίωση κατασκευών.The aim of this study is to investigate the statistical correlations between the point load strength index and certain physical properties, e.g. the dry density and the dry longitudinal ultrasonic wave velocity of prasinites (metabasites). Statistically significant correlations established between the physical properties as well as between each physical quantity and the point load strength index. According to bibliography, this is one of the first efforts to develop relations between physical and mechanical properties for this particular petrological type, and therefore the derived equations can be a useful tool to the investigation of these petrological types, either in the study area or in other sites, where prasinites of similar structural characteristics, are examined for the foundation of various constructions

    Effect of differently fed farmed gilthead sea bream consumption on platelet aggregation and circulating haemostatic markers among apparently healthy adults:A double-blind randomized crossover trial

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    Fish consumption beneficially affects coagulation markers. Few dietary intervention studies have investigated differently fed farmed fish against these cardio-metabolic risk factors in humans. This double-blind randomized crossover trial evaluated differently fed farmed gilthead sea bream consumption against platelet aggregation and circulating haemostatic markers among apparently healthy adults. Subjects aged 30–65 years, with a body mass index 24.0–31.0 kg/m2, consuming less than 150 g cooked fish per week, were recruited in Attica, Greece. Participants were randomized (n = 38, 1:1) to one of two sequences; consumption of fish fed with fish oil diet (conventional fish, CF)/fish fed with olive pomace-enriched diet (enriched fish, EF) versus EF/CF. The primary outcomes were ex vivo human platelet aggregation and circulating plasminogen activator inhibitor-1 (PAI-1) and P-selectin (sP-selectin) concentrations. EF consumption had no significant effect on platelet sensitivity or haemostatic markers compared to CF. Platelet sensitivity to platelet-activating factor (PAF) decreased after CF consumption during the second period (p p < 0.01 for both). Based on current findings, consumption of enriched farmed gilthead sea bream had no greater effect on coagulation markers in adults compared to the conventionally fed fish

    Evolving towards a critical point: A possible electromagnetic way in which the critical regime is reached as the rupture approaches

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    International audienceIn analogy to the study of critical phase transitions in statistical physics, it has been argued recently that the fracture of heterogeneous materials could be viewed as a critical phenomenon, either at laboratory or at geophysical scales. If the picture of the development of the fracture is correct one may guess that the precursors may reveal the critical approach of the main-shock. When a heterogeneous material is stretched, its evolution towards breaking is characterized by the appearance of microcracks before the final break-up. Microcracks produce both acoustic and electromagnetic(EM) emission in the frequency range from VLF to VHF. The microcracks and the associated acoustic and EM activities constitute the so-called precursors of general fracture. These precursors are detectable not only at laboratory but also at geophysical scales. VLF and VHF acoustic and EM emissions have been reported resulting from volcanic and seismic activities in various geologically distinct regions of the world. In the present work we attempt to establish the hypothesis that the evolution of the Earth's crust towards the critical point takes place not only in a mechanical but also in an electromagnetic sense. In other words, we focus on the possible electromagnetic criticality, which is reached while the catastrophic rupture in the Earth's crust approaches. Our main tool is the monitoring of micro-fractures that occur before the final breakup, by recording their radio-electromagnetic emissions. We show that the spectral power law analysis of the electromagnetic precursors reveals distinguishing signatures of underlying critical dynamics, such as: (i) the emergence of memory effects; (ii) the decrease with time of the anti-persistence behaviour; (iii) the presence of persistence properties in the tail of the sequence of the precursors; and (iv) the acceleration of the precursory electro-magnetic energy release. Moreover, the statistical analysis of the amplitudes of the electromagnetic fluctuations reveals the breaking of the symmetry as the theory predicts. Finally, we try to answer the question: how universal the observed electromagnetic critical behaviour of the failing system is

    Chronic exposure to arsenic in the drinking water alters the expression of immune response genes in mouse lung

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    This paper is not subject to U.S. copyright. The definitive version was published in Environmental Health Perspectives 117 (2009): 1108-1115, doi:10.1289/ehp.0800199.Chronic exposure to drinking water arsenic is a significant worldwide environmental health concern. Exposure to As is associated with an increased risk of lung disease, which may make it a unique toxicant, because lung toxicity is usually associated with inhalation rather than ingestion. The goal of this study was to examine mRNA and protein expression changes in the lungs of mice exposed chronically to environmentally relevant concentrations of As in the food or drinking water, specifically examining the hypothesis that As may preferentially affect gene and protein expression related to immune function as part of its mechanism of toxicant action. C57BL/6J mice fed a casein-based AIN-76A defined diet were exposed to 10 or 100 ppb As in drinking water or food for 5–6 weeks. Whole genome transcriptome profiling of animal lungs revealed significant alterations in the expression of many genes with functions in cell adhesion and migration, channels, receptors, differentiation and proliferation, and, most strikingly, aspects of the innate immune response. Confirmation of mRNA and protein expression changes in key genes of this response revealed that genes for interleukin 1β, interleukin 1 receptor, a number of toll-like receptors, and several cytokines and cytokine receptors were significantly altered in the lungs of As-exposed mice. These findings indicate that chronic low-dose As exposure at the current U.S. drinking-water standard can elicit effects on the regulation of innate immunity, which may contribute to altered disease risk, particularly in lung.This work was supported by National Institute of Environmental Health Science grant P42 ES007373 [J.W.H., Superfund Basic Research Program (SBRP) project 2]. C.D.K., A.P.N., and J.A.G. were supported by graduate and postdoctoral fellowships from P42 ES007373 (SBRP, Training Core). C.D.K. was also supported by National Institutes of Health training grant predoctoral fellowship T32-DF007301. P.L.E. and D.J.W. were supported by Cystic Fibrosis Foundation Research grant HL081289

    Spectral Graph Analysis for Process Monitoring

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    Process monitoring is a fundamental task to support operator decisions under ab- normal situations. Most process monitoring approaches, such as Principal Components Analysis and Locality Preserving Projections, are based on dimensionality reduction. In this paper Spectral Graph Analysis Monitoring (SGAM) is introduced. SGAM is a new process monitoring technique that does not require dimensionality reduction techniques. The approach it is based on the spectral graph analysis theory. Firstly, a weighted graph representation of process measurements is developed. Secondly, the process behavior is parameterized by means of graph spectral features, in particular the graph algebraic connectivity and the graph spectral energy. The developed methodology has been illustrated in autocorrelated and non-linear synthetic cases, and applied to the well known Tennessee Eastman process benchmark with promising results.Fil: Musulin, Estanislao. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Centro Internacional Franco Argentino de Ciencias de la Información y Sistemas; Argentin

    Cytotoxic effects of Gemcitabine-loaded liposomes in human anaplastic thyroid carcinoma cells

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    BACKGROUND: Identification of effective systemic antineoplastic drugs against anaplastic thyroid carcinomas has particularly important implications. In fact, the efficacy of the chemotherapeutic agents presently used in these tumours, is strongly limited by their low therapeutic index. METHODS: In this study gemcitabine was entrapped within a pegylated liposomal delivery system to improve the drug antitumoral activity, thus exploiting the possibility to reduce doses to be administered in cancer therapy. The cytotoxic effects of free or liposome-entrapped gemcitabine was evaluated against a human thyroid tumour cell line. ARO cells, derived from a thyroid anaplastic carcinoma, were exposed to different concentrations of the drug. Liposomes formulations were made up of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine/cholesterol/1,2-distearoyl-sn-glycero-3-phosphoethanolamine-MPEG (8:3:1 molar ratio). Cell viability was assessed by both trypan bleu dye exclusion assay and fluorimetric analysis of cell DNA content. RESULTS: A cytotoxic effect of free gemcitabine was present only after 72 h incubation (ARO cell mortality increased of approximately 4 fold over control at 1 μM, 7 fold at 100 μM). When gemcitabine was encapsulated in liposomes, a significant effect was observed by using lower concentrations of the drug (increased cell mortality of 2.4 fold vs. control at 0.3 μM) and earlier exposure time (24 h). CONCLUSION: These findings show that, in vitro against human thyroid cancer cells, the gemcitabine incorporation within liposomes enhances the drug cytotoxic effect with respect to free gemcitabine, thus suggesting a more effective drug uptake inside the cells. This may allow the use of new formulations with lower dosages (side effect free) for the treatment of anaplastic human thyroid tumours
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