Environment-mediated control of a quantum system

Recently, a new approach for the controllability of a two-dimensional quantum system S has been proposed, based on its interaction with an initially uncorrelated two-dimensional probe P whose initial state can be arbitrarily modified. Following this scheme and considering a particular model for the environment, we show that, in some specific cases, the environment-induced entanglement is rich enough to completely control the dynamics of S. Under suitable conditions on the interaction of S, P, and the environment, we prove that the state of S can be driven to an arbitrary target state by varying the initial state of P.     

<Emphasis Type="Italic">CPT</Emphasis> Symmetry and Quantum Mechanics Tests in the Neutral Kaon System at KLOE

The neutral kaon system offers a unique possibility to perform fundamental tests of CPT invariance, as well as of the basic principles of quantum mechanics. The most recent limits obtained by the KLOE experiment at the DAΦNE e ⁺ e ⁻ collider on several kinds of possible CPT violation and decoherence mechanisms, which in some cases might be justified in a quantum gravity framework, are reviewed. No deviation from the expectations of quantum mechanics and CPT symmetry is observed, while the precision of the measurements, in some cases, reaches the interesting Planck scale region. Finally, prospects for this kind of experimental studies at KLOE-2 are presented.     

Measuring financial risk and portfolio optimization with a non-Gaussian multivariate model

In this paper, we propose a multivariate market model with returns assumed to follow a multivariate normal tempered stable distribution. This distribution, defined by a mixture of the multivariate normal distribution and the tempered stable subordinator, is consistent with two stylized facts that have been observed for asset distributions: fat-tails and an asymmetric dependence structure. Assuming infinitely divisible distributions, we derive closed-form solutions for two important measures used by portfolio managers in portfolio construction: the marginal VaR and the marginal AVaR. We illustrate the proposed model using stocks comprising the Dow Jones Industrial Average, first statistically validating the model based on goodness-of-fit tests and then demonstrating how the marginal VaR and marginal AVaR can be used for portfolio optimization using the model. Based on the empirical evidence presented in this paper, our framework offers more realistic portfolio risk measures and a more tractable method for portfolio optimization.     

Chemical Identification of Specialized Metabolites from Sulla (Hedysarum coronarium L.) Collected in Southern Italy

Sulla (Hedysarum coronarium L.) is a biennal forage legume originated from the Mediterranean basin and used for animal feeding due to its high forage quality and palatability. Several species of Hedysarum have been considered for their nutritional, pharmaceutical, and biological properties, and different applications have been reported, both for human consumption and animal nutrition. Although a systematic investigation of the chemical constituents of Hedysarum spp. has been performed in order to provide chemotaxonomic evidences for the genus and to support the pharmacological application of several species within the genus, few data are available on the chemical constituents of H. coronarium, and only the content of condensed tannins and flavonoids in leaves has been previously reported. In the present paper, results from a detailed chemical analysis of the extracts from the leaves and flowers of H. coronarium grown wild in southern Italy are presented. Identification of the main specialized metabolites within the chemical classes of flavonoids, proanthocyanidins and saponins, is described, including considerations on their content in the two plant organs. Information acquired from this study expands the knowledge on H. coronarium as a source of valuable phytochemicals for different applications in human and animal health and nutrition.     

Iron speciation in ancient Attic pottery pigments: a non‐destructive SR‐XAS investigation

The present work reports a detailed investigation on the speciation of iron in the pigments of decorated pottery fragments of cultural heritage relevance. The fragments come from the Gioiosa Guardia archaeological site in the area of the `Strait of Messina' (Sicily, Southern Italy), and date back to VI–V century BC. The purpose of this study is to characterize the main pigmenting agents responsible for the dark‐red coloration of the specimens using non‐destructive analytical techniques such as synchrotron radiation X‐ray absorption spectroscopy (SR‐XAS), a well established technique for cultural heritage and environmental subjects. Absorption spectra were collected at the Fe K‐edge on the Italian beamline for absorption and diffraction (BM8‐GILDA) at the European Synchrotron Radiation Facility in Grenoble (France). In order to determine the speciation of Fe in the samples, principal component analysis and least‐squares fitting procedures were applied to the near‐edge part of the absorption spectra (XANES). Details on the local structure around the Fe sites were obtained by analyzing the extended part of the spectra (EXAFS). Furthermore, an accurate determination of the average Fe oxidation state was carried out through analysis of the pre‐edge peaks of the absorption spectra. Samples resulted composed of an admixture of Fe₂O₃ (hematite or maghemite) and magnetite (Fe₃O₄), occurring in different relative abundance in the dark‐ and light‐colored areas of the specimens. The results obtained are complementary to information previously obtained by means of instrumental neutron activation analysis, Fourier transform infrared absorbance and time‐of‐flight neutron diffraction.     

Variational methods for nonlinear Steklov eigenvalue problems with an indefinite weight function

We consider the problem of finding a harmonic function u in a bounded domain ${\Omega\subset\mathbb{R}^N}$ , N ≥ 2, satisfying a nonlinear boundary condition of the form ${\partial_{\nu}u(x)=\lambda\,\mu(x)h(u(x)), x\in \partial\Omega}$ where μ changes sign and h is an increasing function with superlinear, subcritical growth at infinity. We study the solvability of the problem depending on the parameter λ by using min-max methods.     

Decision algorithms for elementary topology I. Topological syllogistics with set and map constructs,connectedness, and cardinality comparison

In this paper we give a decision procedure for a topological syllogistic, denoted ?²,∞, involving, besides the standard Boolean set operators (∩, ∩, ′ (set complementation)) and predicates ( ? (membership), = (equality)), also the Kuratowski closure operator, continuous and closed maps with the notion of direct and inverse images, surjectivity and injectivity, as well as point evaluation, the singleton operator {·}, a predicate for comparing the cardinalities of two given sets, and a predicate expressing that a given set is topologically connected. Several examples are also discussed. © 1994 John Wiley & Sons, Inc.     

Contact metric manifolds whose characteristic vector field is a harmonic vector field

In this paper, contact metric manifolds whose characteristic vector field ξ is a harmonic vector field are called H-contact manifolds. We show that a (2n+1)-dimensional contact metric manifold is an H-contact manifold if and only if ξ is an eigenvector of the Ricci operator (J.C. González-Dávila and L. Vanhecke [J. Geom. 72 (2001) 65–76] proved this result for n=1). Consequently, the class of H-contact manifolds is very large. Moreover, we give some application about the topology of a compact H-contact manifold.     

Mass spectrometric characterization of poly(ethylene terephthalate-co-p-oxybenzoate)

Copolyesters containing ethylene terephthalate and p-oxybenzoate units in mole ratios of ca. 80:20, 70:30, 40:60, and 20:80, respectively, were examined by direct pyrolysis–mass spectrometry to obtain information about the thermal stabilities and the sequences distributions of the two types of units as a function of composition. Thermal stability as measured by rate of volatilization increased with increasing oxybenzoate content, as did the amount of char residue formed. The electron impact mass spectrum of the volatile fragments showed the formation of predominantly linear fragments with carboxyl and vinyl end groups. Dimer, trimer, and tetramer fragments containing either or both types of units could be identified and their relative amounts could be estimated from peak intensities. The results were consistent with those expected for random distributions of the two units, i.e., for statistical copolymers.     

Stoichiometric hydrogenation of the heterobimetallic (α-alkynyl) complex [μ(1σ, 23η3H2CC  CCH3)] [(CO)3FeCo(CO)3]

The title compound reacts with molecular hydrogen at 60°C giving rise to the homometallic complexes Fe(CO)₅ and Co₂(CO)₈, and a very rich mixture of gaseous hydrocarbons (e.g. butenes from partial hydrogenation, butane from total hydrogenation and methane and propene from selective hydrogenolysis of the organic chain).The influence of concentration of the title complex, and partial pressure of hydrogen or carbon monoxide on the hydrogenation rate have been investigated. Although an unequivocal mechanism cannot be ascertained from the kinetic data owing to the complexity of the reaction, the pattern of products strongly indicates that the σ-interaction between the iron atom and the organic chain is preserved in the transition state.