7,177 research outputs found

    MAGDA: A Mobile Agent based Grid Architecture

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    Mobile agents mean both a technology and a programming paradigm. They allow for a flexible approach which can alleviate a number of issues present in distributed and Grid-based systems, by means of features such as migration, cloning, messaging and other provided mechanisms. In this paper we describe an architecture (MAGDA – Mobile Agent based Grid Architecture) we have designed and we are currently developing to support programming and execution of mobile agent based application upon Grid systems

    Dynamics of a particle confined in a two-dimensional dilating and deforming domain

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    Some recent results concerning a particle confined in a one-dimensional box with moving walls are briefly reviewed. By exploiting the same techniques used for the 1D problem, we investigate the behavior of a quantum particle confined in a two-dimensional box (a 2D billiard) whose walls are moving, by recasting the relevant mathematical problem with moving boundaries in the form of a problem with fixed boundaries and time-dependent Hamiltonian. Changes of the shape of the box are shown to be important, as it clearly emerges from the comparison between the "pantographic", case (same shape of the box through all the process) and the case with deformation.Comment: 13 pages, 2 figure

    International financial flows, domestic banks, and the economic development of the periphery: Italy 1861-1913

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    This paper analyses the impact of different sources of financing (foreign capital, migrants’ remittances, and domestic banks intermediation) on economic development in Italy between 1861 and WWI. Existing literature has analysed the role of these channels of financial intermediation separately, while this paper for the first time considers them in conjunction. Using IRF from a Cholesky identification structure of a VAR model and relying on an original dataset that combines the most recent series of several financial and economic aggregates, this paper shows that both international capital and domestic saving had a significant impact on investment, while remittances did not. Foreign capital was invested directly, but also via domestic banks, in particular the “German-style” universal banks. Finally, foreign and d omestic capital had different attitudes towards the types of investment (construction vs. plant, machinery and transport equipment) and industries they financed. Combined together, these results shed a new light on the process of economic development of Italy and, more generally, of peripheral economies in the age of the international gold standard

    A HIERARCHICAL DISTRIBUTED SHARED MEMORY PARALLEL BRANCH & BOUND APPLICATION WITH PVM AND OPENMP FOR MULTIPROCESSOR CLUSTERS

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    Branch&Bound (B&B) is a technique widely used to solve combinatorial optimization problems in physics and engineering science. In this paper we show how the combined use of PVM and OpenMP libraries can be a promising approach to exploit the intrinsic parallel nature of this class of application and to obtain efficient code for hybrid computational architectures. We described how both the shared memory and the distributed memory programming models can be applied to implement the same algorithm for the inter-nodes and intra-node parallelization. Some experimental tests on a local area network (LAN) of workstations are finally discussed

    The Multifaceted Activity of the VirF Regulatory Protein in the Shigella Lifestyle

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    Shigella is a highly adapted human pathogen, mainly found in the developing world and causing a severe enteric syndrome. The highly sophisticated infectious strategy of Shigella banks on the capacity to invade the intestinal epithelial barrier and cause its inflammatory destruction. The cellular pathogenesis and clinical presentation of shigellosis are the sum of the complex action of a large number of bacterial virulence factors mainly located on a large virulence plasmid (pINV). The expression of pINV genes is controlled by multiple environmental stimuli through a regulatory cascade involving proteins and sRNAs encoded by both the pINV and the chromosome. The primary regulator of the virulence phenotype is VirF, a DNA-binding protein belonging to the AraC family of transcriptional regulators. The virF gene, located on the pINV, is expressed only within the host, mainly in response to the temperature transition occurring when the bacterium transits from the outer environment to the intestinal milieu. VirF then acts as anti-H-NS protein and directly activates the icsA and virB genes, triggering the full expression of the invasion program of Shigella. In this review we will focus on the structure of VirF, on its sophisticated regulation, and on its role as major player in the path leading from the non-invasive to the invasive phenotype of Shigella. We will address also the involvement of VirF in mechanisms aimed at withstanding adverse conditions inside the host, indicating that this protein is emerging as a global regulator whose action is not limited to virulence systems. Finally, we will discuss recent observations conferring VirF the potential of a novel antibacterial target for shigellosis

    Three years field trials to assess the effect of kaolin made particles and copper on olive-fruit fly (B.oleae Gmelin) infestations in Sicily

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    In most countries of Mediterranean Basin, Bactrocera oleae (Gmel), the olive fruit fly, is the key pest insect on olives. In Sicily this pest causes losses of fruits and a poor quality olive oil. Many researchers have recently carried out some field studies which were based on the use of kaolin and copper against the olive-fruit fly. In the last years these products have been effective several times in reducing olive fly infestation. Kaolin had, also, some important effect in reducing heat-stress in fruit crops and olive-trees. The aim of the present study was to assess the effect of kaolin and copper treatment on olive infestations in Sicily and to evaluate chemical and sensory parameters of oils extracted. For this reason, within 2003-2005, the IX Servizio of Assessorato Regionale Agricoltura e Foreste, selected some olive groves where to carry out trials with kaolin and copper and to realize information and divulgation activities

    Characterization of Strombolian events by using independent component analysis

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    We apply Independent Component Analysis (ICA) to seismic signals recorded at Stromboli volcano. Firstly, we show how ICA works considering synthetic signals, which are generated by dynamical systems. We prove that Strombolian signals, both tremor and explosions, in the high frequency band (>0.5 Hz), are similar in time domain. This seems to give some insights to the organ pipe model generation for the source of these events. Moreover, we are able to recognize in the tremor signals a low frequency component (<0.5 Hz), with a well defined peak corresponding to 30s

    What works to boost social relations and community wellbeing? A scoping review of the evidence

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    Background: Social relations are recognized as an important determinant of individual & community wellbeing. The UK What Works Wellbeing Centre chose “boosting social relations” as a priority topic for systematic review. First, a scoping review was undertaken to identify evidence gaps. Methods: We searched: Cochrane database of systematic reviews, DARE, Campbell Library, DoPHER (EPPI-Centre), Joanne Briggs Institute, MEDLINE, IDOX, CINAHL, PsycINFO, Social Policy & Practice, Social Care Online; relevant websites. Inclusion criteria: Population – communities in OECD countries; Intervention - Any community-based intervention, change in policy, organisation or environment that were designed to boost social relations within the community; Outcomes – social relations, community wellbeing or related synonyms; Study design – systematic & non-systematic reviews published between 2005 and 2016. Studies were selected & data extracted by 3 reviewers, and summarised narratively. Results: 11,257 titles and abstracts were screened, 182 obtained in full & 29 included. Existing evidence tells us: Targeted group interventions that foster social networks & provide meaningful roles can reduce social isolation and/ or loneliness in older people; Volunteering can improve physical & mental health & wellbeing in older people; Effective community engagement produces sustainable improvements in community health & individual wellbeing. Evidence gaps: Interventions for social isolation &/ or loneliness in adults aged up to 65 years; Volunteering in people aged up to 65 years; Social network analyses; Community infrastructure (places & spaces). Stakeholder consultations identified community infrastructure (places & spaces) as the most useful topic for systematic review. Conclusions: A systematic scoping review of reviews, with stakeholder consultation, identified community infrastructure (places & spaces) as an evidence gap. Early findings from the resulting systematic review will be presented

    A systematic review of interventions to boost social relations through improvements in community infrastructure (places and spaces)

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    The aim of this systematic review is to synthesise the available evidence, and describe the quality of that evidence, in relation to interventions that improve or create the community infrastructure that impacts on social relations and/ or community wellbeing. For this review, we are defining community infrastructure as the physical places and spaces where people can come together, formally or informally, to interact and participate in the social life of the community. We intend to produce a synthesis which is accessible and will inform practice and future research in the area
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