SIP-based mobility management in next generation networks

The ITU-T definition of next generation networks includes the ability to make use of multiple broadband transport technologies and to support generalized mobility. Next generation networks must integrate several IP-based access technologies in a seamless way. In this article, we first describe the requirements of a mobility management scheme for multimedia real-time communication services; then, we report a survey of the mobility management schemes proposed in the recent literature to perform vertical handovers between heterogeneous networks. Based on this analysis, we propose an application-layer solution for mobility management that is based on the SIP protocol and satisfies the most important requirements for a proper implementation of vertical handovers. We also implemented our proposed solution, testing it in the field, and proving its overall feasibility and its interoperability with different terminals and SIP servers

Monte Carlo techniques for time-dependent radiative transfer in 3-D supernovae

Monte Carlo techniques based on indivisible energy packets are described for computing light curves and spectra for 3-D supernovae. The radiative transfer is time-dependent and includes all effects of O(v/c). Monte Carlo quantization is achieved by discretizing the initial distribution of 56Ni into radioactive pellets. Each pellet decays with the emission of a single energy packet comprising gamma-ray photons representing one line from either the 56Ni or the 56Co decay spectrum. Subsequently, these energy packets propagate through the homologously-expanding ejecta with appropriate changes in the nature of their contained energy as they undergo Compton scatterings and pure absorptions. The 3-D code is tested by applying it to a spherically-symmetric SN in which the transfer of optical radiation is treated with a grey absorption coefficient. This 1-D problem is separately solved using Castor's co-moving frame moment equations. Satisfactory agreement is obtained. The Monte Carlo code is a platform onto which more advanced treatments of the interactions of matter and radiation can be added. Some of these have already been developed and tested in previous papers and are summarized here.Comment: 14 pages, 5 figures. Accepted by A&

Network Friendly P2P-TV: The Napa-Wine Approach

DEMO Sessio

Drivers of Small-Scale Fishers’ Acceptability across Mediterranean Marine Protected Areas at Different Stages of Establishment

The success of marine protected areas (MPAs) in achieving conservation and sustainable development goals hinges on, among other things, their social acceptability by local communities. Small-scale fishing communities represent a key stakeholder category within and around MPAs. Although many authors have examined the social acceptability of MPAs, relatively few studies have addressed this issue by considering how MPA acceptability is built and can be preserved. This study assessed the latent structure of MPA social acceptability and identified the individual and institutional variables driving stakeholders’ acceptability. Using questionnaire surveys, 124 small-scale fishers’ perceptions of MPAs and their social acceptability were explored in six Mediterranean MPAs (three were implemented, and three were designated). The results show that MPA acceptability is positively related to fishers’ age. The findings also highlight that the formal establishment of MPAs is not a sufficient condition for increasing MPA acceptability among fishers. Considerations about the possibility that MPA acceptability can be increased by building support and compliance emerged. MPA managers should implement successful long-term stakeholder engagement initiatives to increase commitment around conservation measures and to improve overall MPA effectiveness

Analysis of Acoustic Emission Activity during Progressive Failure in Heterogeneous Materials: Experimental and Numerical Investigation

This work focuses on an experimental and numerical investigation into monitoring damage in a cube-shaped concrete specimen under compression. Experimental monitoring uses acoustic emission (AE) signals acquired by two independent measurement apparatuses, and the same damage process is numerically simulated with the lattice discrete element method (LDEM). The results from the experiment and simulation are then compared in terms of their failure load, final configurations, and the evolution of global parameters based on AE signals, such as the b-value coefficient and the natural time approach. It is concluded that the results from the AE analysis present a significant sensitivity to the characteristics of the acquisition systems. However, natural time methods are more robust for determining such differences, indicating the same general tendency for all three data sets

Long-Range Correlations and Natural Time Series Analyses from Acoustic Emission Signals

This work focuses on analyzing acoustic emission (AE) signals as a means to predict failure in structures. There are two main approaches that are considered: (i) long-range correlation analysis using both the Hurst (H) and the detrended fluctuation analysis (DFA) exponents, and (ii) natural time domain (NT) analysis. These methodologies are applied to the data that were collected from two application examples: a glass fiber-reinforced polymeric plate and a spaghetti bridge model, where both structures were subjected to increasing loads until collapse. A traditional (AE) signal analysis was also performed to reference the study of the other methods. The results indicate that the proposed methods yield reliable indication of failure in the studied structures

Anabolic effects and inhibition of interleukin 6 production induced by neridronate on human osteoblasts

Bisphosphonates (BPs) are pharmacological compounds widely used in the treatment of a variety of bone-related diseases, particularly where the bone-turnover is skewed in favour of osteolysis. The mechanisms by which BPs reduce bone-resorption directly acting on osteoclasts (OCs) are now largely clarified even at molecular level. The researches concerning the BPs effects on osteoblasts (OBs) have instead shown variable results. Objectives: We have investigated the efficacy of neridronate (NER), an amino-BP, as anabolic agent on human OBs. Moreover, we have tried to verify if NER is able to negatively modulate the production of IL-6 on OBs stimulated or not by the pro-inflammatory cytokine Il-1b. Methods: We have tested if different concentrations of NER (from 10-11M to 10-3M), added to primary human OB cultures, could affect the cells number, the endogenous cellular alkaline phosphatase (ALP) activity, the collagen I (COLI) synthesis, the formation of mineralized nodules and the IL-6 production. Our experimental approach was performed testing a wide range of NER concentrations because, under physiological conditions, OBs seems to be exposed to variable and transient levels of the drug. Results: Our results show that NER doesn't negatively affect in vitro the viability, proliferation and cellular activity of human OBs, even after 20 days of exposure to concentrations ²10-5 M (therapeutic dose). In addition, NER seems to enhance the differentiation of cultured OBs in mature bone-forming cells. A maximum increase of COL-I synthesis (+25% after 4 days; p<0.05), ALP activity (+50% after 10 days; p<0.01) and mineralized nodules (+48% after 20 days; p<0.05) was observed in cultures treated with NER 10-8M. A maximal reduction of IL-6 secretion (-24% on IL-1b stimulated cultures and -29% on unstimulated cultures) was observed for NER 10-9 M. Conclusions: These results encourage the use of neridronate in therapy of demineralizing metabolic bone disorders

Searching for sub-stellar companion into the LkCa15 proto-planetary disk

Recent sub-millimetric observations at the Plateau de Bure interferometer evidenced a cavity at ~ 46 AU in radius into the proto-planetary disk around the T Tauri star LkCa15 (V1079 Tau), located in the Taurus molecular cloud. Additional Spitzer observations have corroborated this result possibly explained by the presence of a massive (>= 5 MJup) planetary mass, a brown dwarf or a low mass star companion at about 30 AU from the star. We used the most recent developments of high angular resolution and high contrast imaging to search directly for the existence of this putative companion, and to bring new constraints on its physical and orbital properties. The NACO adaptive optics instrument at VLT was used to observe LkCa15 using a four quadrant phase mask coronagraph to access small angular separations at relatively high contrast. A reference star at the same parallactic angle was carefully observed to optimize the quasi-static speckles subtraction (limiting our sensitivity at less than 1.0). Although we do not report any positive detection of a faint companion that would be responsible for the observed gap in LkCa15's disk (25-30 AU), our detection limits start constraining its probable mass, semi-major axis and eccentricity. Using evolutionary model predictions, Monte Carlo simulations exclude the presence of low eccentric companions with masses M >= 6 M Jup and orbiting at a >= 100 AU with significant level of confidence. For closer orbits, brown dwarf companions can be rejected with a detection probability of 90% down to 80 AU (at 80% down to 60 AU). Our detection limits do not access the star environment close enough to fully exclude the presence of a brown dwarf or a massive planet within the disk inner activity (i.e at less than 30 AU). Only, further and higher contrast observations should unveil the existence of this putative companion inside the LkCa15 disk.Comment: 6 pages, 4 figures, accepted for publication in A&