A new electric streamer for the characterization of river embankments

River embankments are linear earth structures, worldwide diffused, commonly used for flood protection. Their integrity and stability are fundamental prerequisites for the protection efficiency they can offer to the increasing frequency and magnitude of extreme flood events associated to changes in climate. Proper characterization and monitoring are essential to verify the construction requirements of newly built structures and to evaluate the durability of aged ones. Considering their linear extent, the characterization requires not only local geotechnical investigations but also the application of efficient and economically affordable methods. This is even more essential when the investigations are performed after, or in foresee of, significant flood events, when these structures get stressed and timing of the surveys is crucial. In these conditions, new survey methodologies, with the use of mobile systems, are a main research topic. In this paper the application of a new electric streamer, specifically designed for these aims, is presented. The technical solutions adopted for its construction are described and its application to the characterization of three different river embankments is presented. These case studies were chosen in accordance with the Po River Interregional Agency (AIPO), which is the authority deputed to the safety of flood protection structures in North-West Italy, along the hydrographic network of the Po River. The selected embankments are all earth structures, constructed above the natural alluvial soils, but are characterized by different conditions and challenges. The results obtained with the new system were comparable to standard Electric Resistivity Tomography (ERT) methods. The new system has significant advantages in terms of reducing the survey time, improving the efficiency of the surveys and increasing the data coverage. This resulted in a better definition of potentially dangerous anomalies

On the nature of fear and anxiety triggered by COVID-19

Emergencies that occur during natural disasters, such as avalanches, earthquakes, and floods, tend to be sudden, unexpected, and ephemeral and recruit defensive responses, similar to the ones recruited when faced with dangerous animals. Defensive behaviors are triggered by activity in survival circuits that detects imminent threats and fear is the conscious emotion of that follows immediately. But this particular threat (COVID-19) is useable and mysterious, triggering anxieties much more than fear. We conducted a literature search on May 1, 2020 in Google Scholar, PsychInfo, and PubMed with search terms related to COVID-19 fears and found 28 relevant articles. We categorized the papers into six groups based on the content and implications: fear of the unknown, social isolation, hypochondriasis, disgust, information-driven fears, and compliance.info:eu-repo/semantics/publishedVersio

Performance of Computer Systems; Proceedings of the 4th International Symposium on Modelling and Performance Evaluation of Computer Systems, Vienna, Austria, February 6-8, 1979

These proceedings are a collection of contributions to computer system performance, selected by the usual refereeing process from papers submitted to the symposium, as well as a few invited papers representing significant novel contributions made during the last year. They represent the thrust and vitality of the subject as well as its capacity to identify important basic problems and major application areas. The main methodological problems appear in the underlying queueing theoretic aspects, in the deterministic analysis of waiting time phenomena, in workload characterization and representation, in the algorithmic aspects of model processing, and in the analysis of measurement data. Major areas for applications are computer architectures, data bases, computer networks, and capacity planning. The international importance of the area of computer system performance was well reflected at the symposium by participants from 19 countries. The mixture of participants was also evident in the institutions which they represented: 35% from universities, 25% from governmental research organizations, but also 30% from industry and 10% from non-research government bodies. This proves that the area is reaching a stage of maturity where it can contribute directly to progress in practical problems

Thermal and thermo-oxidative stability and kinetics of decomposition of PHBV/sisal composites

The decomposition behaviours of composites made of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and sisal were assessed in terms of thermal stability and decomposition kinetics, under inert and oxidative conditions, by means of multi-rate linear non-isothermal thermogravimetric experiments. A statistical design of experiments was applied to study the influence of the addition of sisal (0-10-20-30%wt), the presence coupling agent (Yes/No) and the applied conditions of work (inert or oxidative). An improvement of the thermal and thermo-oxidative stability of PHBV with the addition of sisal was observed for all cases. An accurate methodology based on iso-conversional methods was applied to simulate the potential of thermal recovery technologies, such as pyrolysis and controlled combustion, to use these biocomposites after the end of their service life. The mathematical descriptions of both thermo-chemical reactions were helpful in the evaluation of the eventual optimal operational conditions to carry out a suitable energetic valorisation. A minimum of 240°C and 137 kJ/mol of activation energy in inert conditions and 236°C and 118 kJ/mol in oxidative conditions ensured the feasibility of the reactions regardless the composition of the PHBV/sisal biocomposites, which may ease the operability of further energy valorisation with the aim to turn biowaste into new fuels

Conformational and Immunogenicity Studies of the Shigella flexneri Serogroup 6 O-Antigen: The Effect of O-Acetylation.

The pathogenic bacterium Shigella is a leading cause of diarrheal disease and mortality, disproportionately affecting young children in low-income countries. The increasing prevalence of antibiotic resistance in Shigella necessitates an effective vaccine, for which the bacterial lipopolysaccharide O-antigen is the primary target. S. flexneri serotype 6 has been proposed as a multivalent vaccine component to ensure broad protection against Shigella. We have previously explored the conformations of S. flexneri O-antigens from serogroups Y, 2, 3, and 5 that share a common saccharide backbone (serotype Y). Here we consider serogroup 6, which is of particular interest because of an altered backbone repeat unit with non-stoichiometric O-acetylation, the antigenic and immunogenic importance of which have yet to be established. Our simulations show significant conformational changes in serogroup 6 relative to the serotype Y backbone. We further find that O-acetylation has little effect on conformation and hence may not be essential for the antigenicity of serotype 6. This is corroborated by an in vivo study in mice, using Generalized Modules for Membrane Antigens (GMMA) as O-antigen delivery systems, that shows that O-acetylation does not have an impact on the immune response elicited by the S. flexneri serotype 6 O-antigen

Mechanical and thermal performance of PLA and PHBV based biopolymers as potential alternatives to PET

[EN] The evaluation of the mechanical and thermal properties of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polylactide (PLA) and their biocomposites (containing 30%wt of sisal in their composition) has been studied and compared to poly(ethylene terephthalate) (PET). The addition of sisal to the biopolymeric matrix increased the elastic stiffness of the bio-composites achieving a performance which is comparable to PET. All biocomposites presented lower traction resistance and elongation values respect to PET.The addition of natural fibers improved the thermal stability of PHBV-based samples. The trigger of decomposition happened at lower temperatures respect to PET, but always far above their melting point ensuring a good performance of the composites at high processing temperatures. The apparent activation energies for the biocomposites in inert conditions respect to those for PET indicates a more suitable scenario from the energetic valorisation point of view.Moliner, C.; Badia, J.; Bosio, B.; Arato, E.; Lagazzo, A.; Capurro, M.; Ribes-Greus, A. (2017). Mechanical and thermal performance of PLA and PHBV based biopolymers as potential alternatives to PET. Chemical Engineering Transactions. 57:1417-1422. https://doi.org/10.3303/CET1757237S141714225