Expansion-induced contribution to the precession of binary orbits

We point out the existence of new effects of global spacetime expansion on local binary systems. In addition to a possible change of orbital size, there is a contribution to the precession of elliptic orbits, to be added to the well-known general relativistic effect in static spacetimes, and the eccentricity can change. Our model calculations are done using geodesics in a McVittie metric, representing a localized system in an asymptotically Robertson-Walker spacetime; we give a few numerical estimates for that case, and indicate ways in which the model should be improved.Comment: revtex, 7 pages, no figures; revised for publication in Classical and Quantum Gravity, with minor changes in response to referees' comment

A Client-Server Architecture for Distributed Measurement Systems

This paper describes a client-server architecture for the remote control of instrumentation over the Internet network. The proposed solution allows multiuser, multi-instrument sessions by means of a queueing and instrument locking capability. Client applications can be easily developed by using conventional high-level programming languages or well-assessed virtual instrumentation frameworks. Performance tests are reported; they show the low overhead due to network operation with respect to the direct control of instrumentatio

Downscaling stream flow time series from monthly to daily scales using an auto-regressive stochastic algorithm: StreamFARM

Downscaling methods are used to derive stream flow at a high temporal resolution from a data series that has a coarser time resolution. These algorithms are useful for many applications, such as water management and statistical analysis, because in many cases stream flow time series are available with coarse temporal steps (monthly), especially when considering historical data; however, in many cases, data that have a finer temporal resolution are needed (daily). In this study, we considered a simple but efficient stochastic auto-regressive model that is able to downscale the available stream flow data from monthly to daily time resolution and applied it to a large dataset that covered the entire North and Central American continent. Basins with different drainage areas and different hydro-climatic characteristics were considered, and the results show the general good ability of the analysed model to downscale monthly stream flows to daily stream flows, especially regarding the reproduction of the annual maxima. If the performance in terms of the reproduction of hydrographs and duration curves is considered, better results are obtained for those cases in which the hydrologic regime is such that the annual maxima stream flow show low or medium variability, which means that they have a low or medium coefficient of variation; however, when the variability increases, the performance of the model decreases

Characterization and evaluation of a marine protected area: 'Tavolara - Punta Coda Cavallo' (Sardinia, NW Mediterranean)

Habitat mapping plays a key role in the management and conservation of natural systems. In protected areas, where sustainable development is always subordinate to conservation efforts, maps are largely used to represent habitats, development pressures, tourist facilities or legal restrictions such as the zoning of a protected area. Some authors have recently developed a methodology that allows the production of a set of maps for the management of marine protected areas. In this paper, we present the application of this methodology to the case study of the marine protected area 'Tavolara Punta Coda Cavallo'. © 2013 Copyright A. Rovere

Characterization and evaluation of a marine protected area: ‘Tavolara – Punta Coda Cavallo’ (Sardinia, NW Mediterranean)

Habitat mapping plays a key role in the management and conservation of natural systems. In protected areas, where sustainable development is always subordinate to conservation efforts, maps are largely used to represent habitats, development pressures, tourist facilities or legal restrictions such as the zoning of a protected area. Some authors have recently developed a methodology that allows the production of a set of maps for the management of marine protected areas. In this paper, we present the application of this methodology to the case study of the marine protected area ‘Tavolara Punta Coda Cavallo’

Inducing Barbero-Immirzi Connections along SU(2)-reductions of Bundles on Spacetime

We shall present here a general apt technique to induce connections along bundle reductions which is different from the standard restriction. This clarifies and generalizes the standard procedure to define Barbero-Immirzi (BI) connection, though on spacetime. The standard spacial BI connection used in LQG is then obtained by its spacetime version by standard restriction. The general prescription to define such a reduced connection is interesting from a mathematical viewpoint and it allows a general and direct control on transformation laws of the induced object. Moreover, unlike what happens by using standard restriction, we shall show that once a bundle reduction is given, then any connection induces a reduced connection with no constraint on the original holonomy as it happens when connections are simply restricted.Comment: 6 pages, some comments adde

Silver nanocluster/silica composite coatings obtained by sputtering for antibacterial applications

Silver nanocluster silica composite coatings were deposited by radio frequency co-sputtering technique on several substrates. This versatile method allows tailoring of silver content and antibacterial behaviour of coatings deposited on glasses, ceramics, metals and polymers for several applications. Coating morphology and composition as well as nanocluster size were analyzed by means of UV-Visible absorption, X-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), electron dispersive spectroscopy (EDS), X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM). The antibacterial effect was verified through the inhibition halo test against standard bacterial strain, Staphylococcus aureus, before and after sterilization process. Tape test demonstrated a good adhesion of the coatings to the substrate

Conserved Quantities from the Equations of Motion (with applications to natural and gauge natural theories of gravitation)

We present an alternative field theoretical approach to the definition of conserved quantities, based directly on the field equations content of a Lagrangian theory (in the standard framework of the Calculus of Variations in jet bundles). The contraction of the Euler-Lagrange equations with Lie derivatives of the dynamical fields allows one to derive a variational Lagrangian for any given set of Lagrangian equations. A two steps algorithmical procedure can be thence applied to the variational Lagrangian in order to produce a general expression for the variation of all quantities which are (covariantly) conserved along the given dynamics. As a concrete example we test this new formalism on Einstein's equations: well known and widely accepted formulae for the variation of the Hamiltonian and the variation of Energy for General Relativity are recovered. We also consider the Einstein-Cartan (Sciama-Kibble) theory in tetrad formalism and as a by-product we gain some new insight on the Kosmann lift in gauge natural theories, which arises when trying to restore naturality in a gauge natural variational Lagrangian.Comment: Latex file, 31 page