4,472 research outputs found
The debt choices of the firms in Developed Countries: evidence from G-7
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
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
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
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
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
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
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
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
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