1,622 research outputs found

    Weighted Multipolar Hardy Inequalities in R^N and Kolmogorov Type Operators

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    The main purpose of the thesis, which describes the topics I was involved and the results achieved so far, is to introduce the multipolar weighted Hardy inequalities in R^N in the context of the study of Kolmogorov type operators perturbed by singular potentials and of the related evolution problems. The thesis describes, in the first part (Chapter 1), the reference results we can find in literature about the behaviour of the operators with inverse square potentials in the unipolar and multipolar case (existence and nonexistence of positive solutions to evolution problems with Schrodinger and Kolmogorov type operators and positivity of the quadratic form associated with Schrodinger operators). Furthermore we recall the Hardy inequalities in the case of Lebesgue measure and in the weighted case. In the second part (Chapters 2 and 3) we report our results about Kolmogorov type operators and weighted Hardy inequalities

    Context-Aware Handover Policies in HetNets

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    Next generation cellular systems are expected to entail a wide variety of wireless coverage zones, with cells of different sizes and capacities that can overlap in space and share the transmission resources. In this scenario, which is referred to as Heterogeneous Networks (HetNets), a fundamental challenge is the management of the handover process between macro, femto and pico cells. To limit the number of handovers and the signaling between the cells, it will hence be crucial to manage the user's mobility considering the context parameters, such as cells size, traffic loads, and user velocity. In this paper, we propose a theoretical model to characterize the performance of a mobile user in a HetNet scenario as a function of the user's mobility, the power profile of the neighboring cells, the handover parameters, and the traffic load of the different cells. We propose a Markov-based framework to model the handover process for the mobile user, and derive an optimal context-dependent handover criterion. The mathematical model is validated by means of simulations, comparing the performance of our strategy with conventional handover optimization techniques in different scenarios. Finally, we show the impact of the handover regulation on the users performance and how it is possible to improve the users capacity exploiting context information

    GRID Computing and Computational Immunology

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    Clinical efficacy issues in the treatment of multiple sclerosis: update of natalizumab

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    Multiple sclerosis is a frequent neurologic disease, which causes sensory impairment, fatigue, cognitive deficits, imbalance, loss of mobility, spasticity, and bladder and bowel dysfunction. Several new therapies have been introduced in the past decade, but additional drugs are needed to slow disease progression and reduce disability. Natalizumab (NA) is an α4 integrin antagonist, effective in decreasing the development of brain lesions in experimental models and in several studies of patients with MS. Six randomized controlled trials of NA in MS have been published in the last 10 years. Overall, 2,688 relapsing-remitting MS subjects have been enrolled in these studies. Hence, there are already sufficient data to draw some conclusions about the effectiveness of NA in the treatment of MS, although for definitive considerations it would be reasonable to wait for the observational phase IV studies of clinical practice to complete. Moreover, the medical community is concerned with the safety of NA, particularly with the risk of developing progressive multifocal leukoencephalopathy while on NA therapy. From the analyses of the six cases, it seems that the overall risk is around 1/1,000 and could increase with the number of NA infusions

    The compositional and mineralogical analysis of fired pigments in Nasca pottery from Cahuachi (Peru) by the combined use of the portable PIXE-alpha and portable XRD techniques

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    Abstract An analytical protocol based on the combined use of the portable PIXE-alpha (Particle Induced X-ray Emission) and XRD (X-ray Diffraction) non destructive techniques developed at the LANDIS laboratory (Laboratorio di Analisi Non Distruttive) of the INFN–CNR (Istituto Nazionale di Fisica Nucleare–Consiglio Nazionale delle Ricerche) in Catania (Italy), was applied for the characterisation of the surface paints of some archaeological fragments of Nasca pottery from the Ceremonial Centre of Cahuachi in Southern Peru. Measurements were carried out on the black, white, red, orange and grey pigments; quantitative information on the chemical composition as well as on the mineralogical phases present on the paints were obtained. Results allowed to make some considerations about the materials and the manufacturing technique used to realise such fired pigments. It should be noted that during firing the precursor minerals composing the pigments undergo a phase transformation and their identification presents some difficulties

    PETAL: a python tool for deep analysis of biological pathways.

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    Abstract Summary Although several bioinformatics tools have been developed to examine signaling pathways, little attention has been given to ever long-distance crosstalk mechanisms. Here, we developed PETAL, a Python tool that automatically explores and detects the most relevant nodes within a KEGG pathway, scanning and performing an in-depth search. PETAL can contribute to discovering novel therapeutic targets or biomarkers that are potentially hidden and not considered in the network under study. Availabilityand implementation PETAL is a freely available open-source software. It runs on all platforms that support Python3. The user manual and source code are accessible from https://github.com/Pex2892/PETAL
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