40 research outputs found

    A characterization of varieties whose universal cover is a bounded symmetric domain without ball factors

    Get PDF
    We give two characterizations of varieties whose universal cover is a bounded symmetric domain without ball factors in terms of the existence of a holomorphic endomorphism ss of the tensor product TTT\otimes T' of the tangent bundle TT with the cotangent bundle TT'. To such a curvature type tensor \s one associates the first Mok characteristic cone CSCS, obtained by projecting on TT the intersection of ker(s)ker (s) with the space of rank 1 tensors. The simpler characterization requires that the projective scheme associated to CSCS be a finite union of projective varieties of given dimensions and codimensions in their linear spans which must be skew and generat

    Reduced Antioxidant Response of the Fan Mussel Pinna nobilis Related to the Presence of Haplosporidium pinnae

    Get PDF
    The endemic fan mussel (Pinna nobilis) in the Mediterranean Sea is at high risk of disappearance due to massive mortality events. The aim of the study was to evaluate the antioxidant response of P. nobilis collected in the Balearic Islands (Western Mediterranean) before and after the mass mortality event. Individuals collected before (between 2011 and 2012) and after (between 2016 and 2017) the event were analyzed by histological, molecular, and biochemical methods to compare pathogenic loads and biochemical responses. All the individuals collected during 2016–2017 presented symptoms of the disease and were positive for Haplosporidium pinnae, while acid-fast bacteria or/and Gram-negative bacteria were detected in some individuals of both sampling periods. The activities of the antioxidant enzymes catalase and superoxide dismutase in the gills were significantly lower in P. nobilis a ected with the parasite compared to those in the asymptomatic ones, while levels of malondialdehyde, as an indicator of lipid peroxidation, were higher in infected individuals. When analyzing the di erential e ects of H. pinnae and Mycobacterium sp. on P. nobilis, it was observed that significant e ects on biomarkers were only observed in the presence of H. pinnae. Co-infection of P. nobilis by H. pinnae with other pathogens such as Mycobacterium sp. constitutes a serious problem due to its high mortality rate in the Balearic Island waters. This concerning situation for P. nobilis is favored by a reduction in antioxidant defenses related to H. pinnae infection that induces oxidative stress and cell damage.En prens

    Disrupting resilient criminal networks through data analysis: The case of Sicilian Mafia

    Get PDF
    Compared to other types of social networks, criminal networks present particularly hard challenges, due to their strong resilience to disruption, which poses severe hurdles to Law-Enforcement Agencies (LEAs). Herein, we borrow methods and tools from Social Network Analysis (SNA) to (i) unveil the structure and organization of Sicilian Mafia gangs, based on two real-world datasets, and (ii) gain insights as to how to efficiently reduce the Largest Connected Component (LCC) of two networks derived from them. Mafia networks have peculiar features in terms of the links distribution and strength, which makes them very different from other social networks, and extremely robust to exogenous perturbations. Analysts also face difficulties in collecting reliable datasets that accurately describe the gangs’ internal structure and their relationships with the external world, which is why earlier studies are largely qualitative, elusive and incomplete. An added value of our work is the generation of two real-world datasets, based on raw data extracted from juridical acts, relating to a Mafia organization that operated in Sicily during the first decade of 2000s. We created two different networks, capturing phone calls and physical meetings, respectively. Our analysis simulated different intervention procedures: (i) arresting one criminal at a time (sequential node removal); and (ii) police raids (node block removal). In both the sequential, and the node block removal intervention procedures, the Betweenness centrality was the most effective strategy in prioritizing the nodes to be removed. For instance, when targeting the top 5% nodes with the largest Betweenness centrality, our simulations suggest a reduction of up to 70% in the size of the LCC. We also identified that, due the peculiar type of interactions in criminal networks (namely, the distribution of the interactions’ frequency), no significant differences exist between weighted and unweighted network analysis. Our work has significant practical applications for perturbing the operations of criminal and terrorist networks

    EuFRATE: European FPGA Radiation-hardened Architecture for Telecommunications

    Get PDF
    The EuFRATE project aims to research, develop and test radiation-hardening methods for telecommunication payloads deployed for Geostationary-Earth Orbit (GEO) using Commercial-Off-The-Shelf Field Programmable Gate Arrays (FPGAs). This project is conducted by Argotec Group (Italy) with the collaboration of two partners: Politecnico di Torino (Italy) and Technische Universit¨at Dresden (Germany). The idea of the project focuses on high-performance telecommunication algorithms and the design and implementation strategies for connecting an FPGA device into a robust and efficient cluster of multi-FPGA systems. The radiation-hardening techniques currently under development are addressing both device and cluster levels, with redundant datapaths on multiple devices, comparing the results and isolating fatal errors. This paper introduces the current state of the project’s hardware design description, the composition of the FPGA cluster node, the proposed cluster topology, and the radiation hardening techniques. Intermediate stage experimental results of the FPGA communication layer performance and fault detection techniques are presented. Finally, a wide summary of the project’s impact on the scientific community is provided

    A characterization of varieties whose universal cover is the polydisk or a tube domain

    Get PDF
    In this article we give necessary and sufficient conditions, in terms of certain tensors called semispecial tensors, respectively slope zero tensors, in order that the universal covering of a complex projective manifold be a symmetric domain of tube type. As an application, we give precisions of a result of Kazhdan showing that a Galois conjugate of such a manifold has the same universal coverin

    Wide-Geographic and Long-Term Analysis of the Role of Pathogens in the Decline of Pinna nobilis to Critically Endangered Species

    Get PDF
    A mass mortality event (MME) affecting the fan mussel Pinna nobilis was first detected in Spain in autumn 2016 and spread north- and eastward through the Mediterranean Sea. Various pathogens have been blamed for contributing to the MME, with emphasis in Haplosporidium pinnae, Mycobacterium sp. and Vibrio spp. In this study, samples from 762 fan mussels (necropsies from 263 individuals, mantle biopsies from 499) of various health conditions, with wide geographic and age range, taken before and during the MME spread from various environments along Mediterranean Sea, were used to assess the role of pathogens in the MME. The number of samples processed by both histological and molecular methods was 83. The most important factor playing a main role on the onset of the mass mortality of P. nobilis throughout the Mediterranean Sea was the infection by H. pinnae. It was the only non-detected pathogen before the MME while, during MME spreading, its prevalence was higher in sick and dead individuals than in asymptomatic ones, in MME-affected areas than in non-affected sites, and it was not associated with host size, infecting both juveniles and adults. Conversely, infection with mycobacteria was independent from the period (before or during MME), from the affection of the area by MME and from the host health condition, and it was associated with host size. Gram (-) bacteria neither appeared associated with MME.En prens

    Wide-Geographic and Long-Term Analysis of the Role of Pathogens in the Decline of Pinna nobilis to Critically Endangered Species

    Get PDF
    20 Pág.A mass mortality event (MME) affecting the fan mussel Pinna nobilis was first detected in Spain in autumn 2016 and spread north- and eastward through the Mediterranean Sea. Various pathogens have been blamed for contributing to the MME, with emphasis in Haplosporidium pinnae, Mycobacterium sp. and Vibrio spp. In this study, samples from 762 fan mussels (necropsies from 263 individuals, mantle biopsies from 499) of various health conditions, with wide geographic and age range, taken before and during the MME spread from various environments along Mediterranean Sea, were used to assess the role of pathogens in the MME. The number of samples processed by both histological and molecular methods was 83. The most important factor playing a main role on the onset of the mass mortality of P. nobilis throughout the Mediterranean Sea was the infection by H. pinnae. It was the only non-detected pathogen before the MME while, during MME spreading, its prevalence was higher in sick and dead individuals than in asymptomatic ones, in MME-affected areas than in non-affected sites, and it was not associated with host size, infecting both juveniles and adults. Conversely, infection with mycobacteria was independent from the period (before or during MME), from the affection of the area by MME and from the host health condition, and it was associated with host size. Gram (-) bacteria neither appeared associated with MME.This work was funded by: DG Pesca i Medi Mari (GOIB),EsMarEs (order IEO by MITECO, Spanish government), Life UFE IP-PAF INTEMARES (LIFE15 IPE ES 012) “Gestión integrada, innovadora y participativa de la Red Natura 2000 en el medio marino español,” the research project “Estado de conservación del bivalvo amenazado Pinna nobilis en el PNAC” (OAPN 024/2010), the project RECONNECT (MIS 5017160) of the Programme Interreg V-B “Balkan-Mediterranean 2014–2020.” MTES (French Government), DREAL (Direction Régionale Environnement Aménagement Logement) and Région Occitanie (France) for funding research and monitoring of Pinna.GC and PP were contracted under the INIA-CCAA cooperative research programme for postdoctoral incorporation from the Spanish National Institute for Agricultural and Food Research and Technology (INIA) (DOC INIA 8/2013 and 15/2015). MV-L was supported by a Juan de la Cierva-Incorporación postdoctoral contract (ICJI-2016-29329, MICIU Programme). ML-S and EÁ were supported by a Personal Técnico de Apoyo contract MINECO programme (PTA2015-11709-I and PTA2015-10829- I, respectively). CP and GS were supported by the project RECONNECT (MIS 5017160) financed by the Transnational Cooperation Programme Interreg V-B “Balkan-Mediterranean 2014–2020” and co-funded by the European Union and national funds of the participating countries. CP was supported by Sorbonne University.Peer reviewe

    Higher dimensional Lemniscates: the geometry of r particles in n-space with logarithmic potentials

    No full text
    The main purpose of this paper is to lay down the foundations of the theory of higher dimensional lemniscates and to propose the investigation of several interesting open problems in the field. The underlying geometrical problem is quite old (see \cite{walsh6}, \cite{walsh7}, \cite{nagy4}, \cite{motzkin-walsh}), but, whereas in the past the main question was the location of the critical points of a certain distance function, the main thrust of our approach is to look at the logarithm of this function as the sum of logarithmic potentials at rr points. And the main goal is the topological analysis of the configuration of the singular solutions (of the associated differential equation). We look at the number and type of critical points, and we make a breakthrough in higher dimensions relating the question to modern methods of complex analysis in several variables, showing that any critical point has Hessian with positivity at least (n1)(n-1); hence, for generic choice of the rr points we get a Morse function whose only critical points are local minima and saddles of negativity 1. We also show that the critical points are either isolated, or consists of curves of local minima. The existence or not of these curves, and the upper bound for the number of critical points are related to famous classical problems posed by Morse-Cairns (\cite{cairns-morse} and by Maxwell \cite{maxwell} for the case of electrostatic potentials. We provide examples where the number of extra local minima can be arbitrarily large

    The Nursehound <i>Scyliorhinus stellaris</i> Mitochondrial Genome—Phylogeny, Relationships among Scyliorhinidae and Variability in Waters of the Balearic Islands

    No full text
    The complete mitochondrial DNA sequence of the Nursehound Scyliorhinus stellaris has been determined for the first time and compared with congeneric species. The mitogenome sequence was 16,684 bp in length. The mitogenome is composed of 13 PCGs, 2 rRNAs, 22 transfer RNA genes and non-coding regions. The gene order of the newly sequenced mitogenome is analogous to the organization described in other vertebrate genomes. The typical conservative blocks in the control region were indicated. The phylogenetic analysis revealed a monophyletic origin of the Scyliorhininae subfamily, and within it, two subclades were identified. A significant divergence of Scyliorhinus spp. together with Poroderna patherinum in relation to the group of Cephaloscyllium spp. was observed, except for Scyliorhinus torazame, more related to this last cited clade. A hypothesis of a divergent evolution consequent to a selective pressure in different geographic areas, which lead to a global latitudinal diversity gradient, has been suggested to explain this phylogenetic reconstruction. However, convergent evolution on mitochondrial genes could also involve different species in some areas of the world
    corecore