4,099 research outputs found

    The debt choices of the firms in Developed Countries: evidence from G-7

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    This study examines the main determinants that affect the firm’s debt choices. Based on a panel data of non-financial listed firms in G-7 countries in the period 1994-2013, the study shows that the firm’s choices about debt level are functions of several previsions over time about, on the one hand, to the firm’s characteristics and its expected performances and, on the other hand, to the economic, financial and institutional system of country’s reference

    Two-spin entanglement induced by electron scattering in nanostructures

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    We present a model where two magnetic impurities in a discrete tight-binding ring become entangled because of scattering processes associated to the injection of a conduction electron. We introduce a weak coupling approximation that allows us to solve the problem in a analytical way and compare the theory with the exact numerical results. We obtain the generation of entanglement both in a deterministic way and in a probabilistic one. The first case is intrinsically related to the structure of the two-impurity reduced density matrix, while the second one occurs when a projection on the electron state is performed

    Conditional sign flip via teleportation

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    We present a model to realize a probabilistic conditional sign flip gate using only linear optics. The gate operates in the space of number state qubits and is obtained by a nonconventional use of the teleportation protocol. Both a destructive and a nondestructive version of the gate are presented. In the former case an Hadamard gate on the control qubit is combined with a projective teleportation scheme mixing control and target. The success probability is 1/2. In the latter case we need a quantum encoder realized via the interaction of the control qubit with an ancillary state composed of two maximally entangled photons. The success probability is 1/4

    Gaussian Discriminating Strength

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    We present a quantifier of non-classical correlations for bipartite, multi-mode Gaussian states. It is derived from the Discriminating Strength measure, introduced for finite dimensional systems in A. Farace et al., New. J. Phys. 16, 073010 (2014). As the latter the new measure exploits the Quantum Chernoff Bound to gauge the susceptibility of the composite system with respect to local perturbations induced by unitary gates extracted from a suitable set of allowed transformations (the latter being identified by posing some general requirements). Closed expressions are provided for the case of two-mode Gaussian states obtained by squeezing or by linearly mixing via a beam-splitter a factorized two-mode thermal state. For these density matrices, we study how non-classical correlations are related with the entanglement present in the system and with its total photon number.Comment: 11+6 pages, 4 figure

    Diversity of Rainfall Thresholds for early warning of hydro-geological disasters

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    Abstract. For early warning of disasters induced by precipitation (such as floods and landslides), different kinds of rainfall thresholds are adopted, which vary from each other, on the basis on adopted hypotheses. In some cases, they represent the occurrence probability of an event (landslide or flood), in other cases the exceedance probability of a critical value for an assigned indicator I (a function of rainfall heights), and in further cases they only indicate the exceeding of a prefixed percentage a critical value for I, indicated as Icr. For each scheme, it is usual to define three different criticality levels (ordinary, moderate and severe), which are associated to warning levels, according to emergency plans. This work briefly discusses different schemes of rainfall thresholds, focusing attention on landslide prediction, with some applications to a real case study in Calabria region (southern Italy)

    The good connections:A Network Analysis of organized crime, patronage, and local elites

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    So far, the application of network analysis to crime has been limited to the relationships within criminal networks. We build a novel network dataset by encoding information coming from the archive of the Italian Anti-mafia Commission, describing relationships of collusion and exchange of favours between mafia members and the political, economic and social elites in Sicily, the homeland of the Sicilian mafia. We apply network analysis techniques to study the "topological" role of mafia bosses and show that they strategically position themselves in the social network as an interface between the criminal and the legitimate world

    Sp3 Is a Bifunctional Transcription Regulator with Modular Independent Activation and Repression Domains

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    Sp3 is a member of the Sp family of transcription factors and binds to DNA with affinity and specificity comparable to that of Sp1. We demonstrate that Sp3 is a bifunctional transcription factor that can both activate and repress transcription. Gene fusion experiments in mammalian cells demonstrate that the Sp3 activation potential is distributed over an extensive glutamine-rich N-terminal region, whereas the repressor activity has been mapped in a 72-amino acid region located at the 5' of the zinc finger DNA-binding domain. We demonstrated that the repression activity is strictly dependent on the context of the DNA-binding sites bound by Sp3. We found that Sp3 represses transcription of promoters bearing multiple GAL4 DNA-binding sites, whereas it activates isogenic reporters containing a single GAL4-binding site. Transfection experiments in Drosophila cells that lack endogenous Sp activity demonstrated that Sp3 does not possess an active repression domain that can function in insect cells, rather it is a weak transcriptional activator of the c-myc promoter. Our results strongly suggest that Sp3 is a dual-function regulator whose activity is dependent upon both the promoter and the cellular context

    Mesoscopic continuous and discrete channels for quantum information transfer

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    We study the possibility of realizing perfect quantum state transfer in mesoscopic devices. We discuss the case of the Fano-Anderson model extended to two impurities. For a channel with an infinite number of degrees of freedom, we obtain coherent behavior in the case of strong coupling or in weak coupling off-resonance. For a finite number of degrees of freedom, coherent behavior is associated to weak coupling and resonance conditions

    An investigation of interregional trade network structures

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    We provide empirical evidence on the network structure of trade flows between European regions and discuss the theoretical underpinning of such a structure. First, we analyze EU regional trade data using Social Network Analysis. We describe the topology of this network and compute local and global centrality measures. Finally, we consider the distribution of higher order statistics, through the analysis of local clustering and main triadic structures in the triad census of interregional trade flows. In the theoretical part, we explore the relationship between trade costs and trade links. As shown by Behrens (2004, 2005a, 2005b) in a two-region linear new economic geography (NEG) model, trade costs and the local market size determine, even with finite trade costs, unconditional autarky and unilateral trade, that is, a one-directional flow from one region to the other. Following these contributions and guided by the empirical evidence, we clarify the relationship between market competition, trade costs and the patterns of trade in a three-region NEG model. We identify a larger set of trade network configurations other the three elementary ones that occur at the dyadic level between two regions (no trade, one-way trade, reciprocated two-way trade), and relate the model with the triad census
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