Discontinuities and barriers in communications

The problem of identifying and measuring the effects of linguistic barriers on a contact network in Switzerland is examined. In a nation where four official languages prevail, the public telephone network may be considered as an adequate infrastructure to identify these kinds of effects. Linguistic barriers have been examined in a general way and taking differences in intensity of effect into account. Such differences may exist at the level of specific combinations of language interaction. Statistical estimations have been carried out with the aid of gravity models: one with dummy variables and the other by varying parameters. The main discontinuity in contact patterns arises between the German and French-speaking communities.     

Salmonella typhi O:9,12 polysaccharide-protein conjugates: characterization and immunoreactivity with pooled and individual normal human sera, sera from patients with paratyphoid A and B and typhoid fever, and animal sera

Polysaccharide of O:9,12 specificity purified from Salmonella typhi was conjugated to tetanus toxoid or bovine serum albumin in order to obtain defined antigenic material that would contain O chain free of other S. typhi antigens and that would be suitable for characterizing host humoral response to only S. typhi O-chain antigens. These artificial conjugates were strongly reactive in immunodots with 18 pooled and 3 individual serum samples from patients with typhoid fever and with rabbit anti-Salmonella O antiserum (group D, factors 1, 9, and 12). They reacted weakly with one serum sample from one human with paratyphoid A. These results suggest that the periodate oxidation and the reductive amination used in the conjugation conserved the immunogenicity of the O chain and allowed its absorption to nitrocellulose. They also suggest that the bovine serum albumin conjugate could be used in the diagnosis of S. typhi infections as normal sera may react with the protein molecule of the tetanus toxoid conjugate.     

Application of the wavelet transform to acoustic emission signalsprocessing

In acoustic emission signals processing, a common problem is to extract physical parameters of interest when these involve join variations of time and frequency. In this correspondence, a new family of spline wavelet packets is proposed for these purposes. They improve wavelet analysis, providing a time-scale frequency technique with adaptable precision. An appropriate scheme to decompose a given signal is also exposed     

Integration of a HAP within a Terrestrial UMTS Network: Interference Analysis and Cell Dimensioning

In this paper we consider several issues regarding the use of a High Altitude Platform (HAP) as a mobile communications base station for the UMTS standard. We refer in particular to a solar powered unmanned stratospheric platform named Heliplat, which is currently being designed at Politecnico di Torino within the HeliNet project funded by the European Community as part of the Fifth Framework Programme. Here we present a feasibility study of the use of the Heliplat platform as a UMTS base station within anintegrated terrestrial-stratospheric UMTS cellular system. We take into account the power consumption and the weight constraint imposed by the platform technology, the interference required for a proper system operation and the requirement of maintaining full compatibility with the UMTS standard. This revised version was published online in July 2006 with corrections to the Cover Date.     

Increased plasma levels of the C-C chemokine RANTES in patients with primary HIV-1 infection

To investigate the role played by chemokines in the natural history of human immunodeficiency virus (HIV) infection, we measured the plasma levels of RANTES. MIP-1 alpha and MIP-1 beta in a cohort of patients with primary HIV-1 infection (PHI) followed longitudinally. The cohort included 17 patients with well-documented history of acute HIV syndrome within two months of the first observation. The mean plasma concentration of RANTES, but not that of MIP-1 alpha or MIP-1 beta, was significantly higher in patients with PHI (192.3 ng/ml) than in five HIV-seronegative controls (8.0 ng/ml) studied during the same time period. Treatment of blood with a cocktail of drugs preventing platelet activation, followed by high-speed centrifugation, reduced the levels of RANTES by approximately 2 logs both in patients and in controls, indicating that the bulk of RANTES was released by platelets, which are known to store this chemokine in their alpha-granules, in the immediate aftermath of blood drawing. No correlation was seen between the levels of RANTES and the number of HIV genome equivalents in plasma. These data suggest that large amounts of pre-formed RANTES are stored in platelets and, possibly, in other blood cells during the early phases of HIV infection. The possible role of this HIV-suppressive chemokine in the control of viral replication during PHI remains to be established.     

Automatic authoring and construction of hypermedia for information retrieval

This paper describes the complete process and a tool for the automatic construction of a multimedia hypertext starting from a large collection of multimedia documents. Through the use of an authoring methodology, the document collection is automatically authored, and the result is a multimedia hypertext, also called a hypermedia, written in hypertext mark-up language (HTML), almost a standard among hypermedia mark-up languages. The resulting hypermedia can be browsed and queried with Mosaic, an interface developed in the framework of the World Wide Web Project. In particular, the set of methods and techniques used for the automatic construction of hypermedia is described in this paper, and their relevance in the context of multimedia information retrieval is highlighted.     

Assessment of ettringite from hydrated FBC residues as a sorbent for fluidized bed desulphurization

The performance of synthetic ettringite as a sorbent in fluidized bed desulphurization has been assessed and compared with that of a commercial limestone. Experiments have been carried out in a bench scale fluidized bed reactor under simulated desulphurizing (steadily oxidizing) combustion conditions. Sorbent performance has been characterized in terms of desulphurization rate, maximum sulphur uptake and attrition propensity. Fluidized bed sulphation experiments have been complemented by microstructural characterization of solid samples, accomplished via X-ray diffraction analysis, scanning electron microscopy and sulphur mapping of cross-sections of particles embedded in epoxy resin.

Experimental results show that both the rate and the maximum extent of sulphur uptake by ettringite significantly exceed those of the limestone. Maximum degree of free calcium utilization is 0.58 for ettringite compared with 0.27 for the limestone. Sulphation tests also indicate that attrition propensity of ettringite is larger than that correspondingly observed for the limestone. Microstructural characterization indicates that sulphation of ettringite takes place evenly throughout the particle cross-section, whereas sulphation of limestone mostly conforms to a core-shell pattern.

Along a parallel pathway, the rate and yield of ettringite formation by hydration of fly ash from a utility fluidized bed boiler have been assessed. Formation of ettringite in these experiments appears to be quantitative upon curing of ash at 70 °C for times up to 4 days.     

Inerting and venting of mark II containments in BWR nuclear plants

An analysis of hydrogen control systems corroborates containment inerting as the only way of preventing hydrogen explosions which may jeopardize the integrity of BWR Mark II containments during severe accidents. A severe Large Break LOCA and a severe Stuck Open Relief Valve Accident are simulated by the MARCH 2.0 code to compare the advantages and disadvantages of pre-inerting and post-inerting, with or without venting, in BWR Mark II containments.     

Lactobacillus amylovorus DSM 19280 as a novel food-grade antifungal agent for bakery products

Mould spoilage is the main cause of substantial economic loss in bakery industry and might also cause public health problems due to the production of mycotoxins. The reduction of mould growth in bakery products is thus of crucial importance and there is great interest to develop safe and efficient strategies for this purpose. In this study Lactobacillus amylovorus DSM19280 has been shown to produce a wide spectrum of antifungal compounds active against common bread spoilage fungi. Among the indicator moulds, Aspergillus fumigatus and Fusarium culmorum were the most sensitive organisms. Several antifungal compounds were found to be present in synthetic medium inoculated with L. amylovorus DSM19280 strain, some of them being reported here for the first time. Wheat doughs fermented with L. amylovorus DSM19280 had good rheological properties and the breads thereof were of high quality as shown by rheofermentometer and texture analyser measurements. The results were compared with those obtained with a control non-antifungal L. amylovorus DSM20531^T strain, a non-acidified and a chemically acidified dough. The quality of sourdough and bread fermented with L. amylovorus DSM 19280 was comparable to that obtained by using L. amylovorus DSM20531 ^T. Additionally, breads were evaluated for the ability to retard the growth of Fusarium culmorum FST 4.05, Aspergillus niger FST4.21, Penicillium expansum FST 4.22, Penicillium roqueforti FST 4.11 and fungal flora from the bakery environment. The biological preservation of bread with L. amylovorus DSM 19280 was also compared to the most commonly used antifungal agent Calcium propionate. Breads containing sourdough fermented with L. amylovorus DSM 19280 were more effective in extending the shelf life of bread than the calcium propionate.     

Analysis of RC Hollow Columns Strengthened with GFRP

Reinforced concrete (RC) hollow piers in bridges withstand high moment and shear demands ensured with reduced mass and lower stress on foundations compared with solid piers. Failure of hollow columns is typically affected by premature buckling of reinforcing bars and concrete cover spalling. At present, no guidelines are available for the design of their upgrade, and few research investigations can be found on hollow columns strengthened by using fiber-reinforced polymer (FRP) materials. This paper discusses an experimental program carried out on purely compressed RC hollow columns externally wrapped with glass-fiber-reinforced polymer (GFRP). Three specimens were tested: one specimen was unstrengthened and used as the benchmark; the other two specimens were GFRP-wrapped with different confining reinforcement ratios. Each specimen was designed according to dated codes (i.e., prior to 1970) accounting only for gravity loads. In particular, steel longitudinal bars cross section and steel tie-spacing were designed with the minimum amount of longitudinal reinforcement and minimum tie area at maximum spacing. Tests results highlight that the GFRP-jacket mainly provided ductility increases before low strength increments could be obtained. Refined and simplified numerical models for hollow square RC columns, previously proposed by the authors, herein extend to hollow rectangular members. Comparisons of experimental results and theoretical predictions on the basis of both refined and simplified confinement models were performed and showed good agreement. In the case of the simplified model, a value for the effective ultimate FRP strain was suggested.