229 research outputs found

    Formulazione semplificata per il calcolo in forma chiusa del diagramma Momento-Curvatura di una sezione circolare cava in CA (in Italian)

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    Per un’analisi di vulnerabilità di un ponte a travata è possibile assumere che la curva di capacità della struttura sia approssimabile con la curva di capacità della pila critica. Il comportamento della pila critica può essere, in generale, influenzato da vari meccanismi quali la flessione, il taglio, gli effetti del second’ordine, lo sfilamento delle barre longitudinali o la loro instabilizzazione. Il comportamento flessionale è noto se si conosce il diagramma MomentoCurvatura della sezione d’incastro e la lunghezza di cerniera plastica. Considerando che gli altri meccanismi possono essere valutati con formulazioni approssimate l’aspetto chiave del problema è il diagramma MomentoCurvatura. Dopo aver valutato la sezione circolare piena in lavori precedenti, nella presente memoria si propone una procedura per valutare il diagramma Momento-Curvatura di una sezione circolare cava in C.A. definendo la posizione di alcuni suoi punti caratteristici. Per ognuno di questi si propone una soluzione adimensionale in forma chiusa che dipende da quattro parametri anch’essi adimensionali: rapporto tra raggio del foro e raggio esterno, rapporto di sforzo normale, rapporto meccanico di armatura longitudinale, rapporto volumetrico di staffatura. L’idea di base è quella di avere buone indicazioni sulle prestazioni dei materiali (snervamento, salto del copriferro, collasso, etc) basandosi su pochi parametri di input

    Simplified closed-form solution for the determination of the moment-curvature response of a circular RC section

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    A seismic vulnerability analysis of a multi-span simply supported bridge is often based on the seismic response of the most critical pier. This response is influenced by different collapse modes (flexural, shear, second order effects, lap-splice of longitudinal bars or their buckling). Among these the flexural behaviour is important and it's known if the equivalent plastic hinge length and the Moment-Curvature law of the fixed end are given. This paper provides a closed-form dimensionless solution to obtain a 5 point Moment-Curvature diagram for circular RC section. The solution is based only on three parameters: dimensionless axial force, mechanical percentage of longitudinal reinforcement, geometrical percentage of transversal reinforcement. A numerical example is presented to test the solution comparing it with a FEM analysis

    Causally consistent reversible choreographies: a monitors-as-memories approach

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    Under a reversible semantics, computation steps can be undone. This paper addresses the integration of reversible semantics into a process model of multiparty protocols (choreographies). Building upon the monitors-as-memories approach that we developed in prior work for reversible binary protocols, we present a reversible process framework for multiparty communication, which improves on prior models by seamlessly integrating asynchrony, decoupled rollbacks, and process passing. As main technical result, we prove that our multiparty, reversible semantics is causally-consistent

    Multi-model assessment of the late-winter extra-tropical response to El Niño and La Niña

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    El Niño-Southern Oscillation (ENSO) is known to affect the Northern Hemisphere tropospheric circulation in late-winter (January-March), but whether El Niño and La Niña lead to symmetric impacts and with the same underlying dynamics remains unclear, particularly in the North Atlantic. Three state-of-the-art atmospheric models forced by symmetric anomalous sea surface temperature (SST) patterns, mimicking strong ENSO events, are used to robustly diagnose symmetries and asymmetries in the extra-tropical ENSO response. Asymmetries arise in the sea-level pressure (SLP) response over the North Pacific and North Atlantic, as the response to La Niña tends to be weaker and shifted westward with respect to that of El Niño. The difference in amplitude can be traced back to the distinct energy available for the two ENSO phases associated with the non-linear diabatic heating response to the total SST field. The longitudinal shift is embedded into the large-scale Rossby wave train triggered from the tropical Pacific, as its anomalies in the upper troposphere show a similar westward displacement in La Niña compared to El Niño. To fully explain this shift, the response in tropical convection and the related anomalous upper-level divergence have to be considered together with the climatological vorticity gradient of the subtropical jet, i.e. diagnosing the tropical Rossby wave source. In the North Atlantic, the ENSO-forced SLP signal is a well-known dipole between middle and high latitudes, different from the North Atlantic Oscillation, whose asymmetry is not indicative of distinct mechanisms driving the teleconnection for El Niño and La Niña

    Escherichia coli redox mutants as microbial cell factories for the synthesis of reduced biochemicals

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    Bioprocesses conducted under conditions with restricted O2 supply are increasingly exploited for the synthesis of reduced biochemicals using different biocatalysts. The model facultative aerobe Escherichia coli, the microbial cell factory par excellence, has elaborate sensing and signal transduction mechanisms that respond to the availability of electron acceptors and alternative carbon sources in the surrounding environment. In particular, the ArcBA and CreBC two-component signal transduction systems are largely responsible for the metabolic regulation of redox control in response to O2 availability and carbon source utilization, respectively. Significant advances in the understanding of the biochemical, genetic, and physiological duties of these regulatory systems have been achieved in recent years. This situation allowed to rationally-design novel engineering approaches that ensure optimal carbon and energy flows within central metabolism, as well as to manipulate redox homeostasis, in order to optimize the production of industrially-relevant metabolites. In particular, metabolic flux analysis provided new clues to understand the metabolic regulation mediated by the ArcBA and CreBC systems. Genetic manipulation of these regulators proved useful for designing microbial cells factories tailored for the synthesis of reduced biochemicals with added value, such as poly(3-hydroxybutyrate), under conditions with restricted O2 supply. This network-wide strategy is in contrast with traditional metabolic engineering approaches, that entail direct modification of the pathway(s) at stake, and opens new avenues for the targeted modulation of central catabolic pathways at the transcriptional level

    The development of the Quality Indicator for Rehabilitative Care (QuIRC): a measure of best practice for facilities for people with longer term mental health problems.

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    BACKGROUND: Despite the progress over recent decades in developing community mental health services internationally, many people still receive treatment and care in institutional settings. Those most likely to reside longest in these facilities have the most complex mental health problems and are at most risk of potential abuses of care and exploitation. This study aimed to develop an international, standardised toolkit to assess the quality of care in longer term hospital and community based mental health units, including the degree to which human rights, social inclusion and autonomy are promoted. METHOD: The domains of care included in the toolkit were identified from a systematic literature review, international expert Delphi exercise, and review of care standards in ten European countries. The draft toolkit comprised 154 questions for unit managers. Inter-rater reliability was tested in 202 units across ten countries at different stages of deinstitutionalisation and development of community mental health services. Exploratory factor analysis was used to corroborate the allocation of items to domains. Feedback from those using the toolkit was collected about its usefulness and ease of completion. RESULTS: The toolkit had excellent inter-rater reliability and few items with narrow spread of response. Unit managers found the content highly relevant and were able to complete it in around 90 minutes. Minimal refinement was required and the final version comprised 145 questions assessing seven domains of care. CONCLUSIONS: Triangulation of qualitative and quantitative evidence directed the development of a robust and comprehensive international quality assessment toolkit for units in highly variable socioeconomic and political contexts

    A systematic review of the international published literature relating to quality of institutional care for people with longer term mental health problems.

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    BACKGROUND: A proportion of people with mental health problems require longer term care in a psychiatric or social care institution. However, there are no internationally agreed quality standards for institutional care and no method to assess common care standards across countries. We aimed to identify the key components of institutional care for people with longer term mental health problems and the effectiveness of these components. METHODS: We undertook a systematic review of the literature using comprehensive search terms in 11 electronic databases and identified 12,182 titles. We viewed 550 abstracts, reviewed 223 papers and included 110 of these. A "critical interpretative synthesis" of the evidence was used to identify domains of institutional care that are key to service users' recovery. RESULTS: We identified eight domains of institutional care that were key to service users' recovery: living conditions; interventions for schizophrenia; physical health; restraint and seclusion; staff training and support; therapeutic relationship; autonomy and service user involvement; and clinical governance. Evidence was strongest for specific interventions for the treatment of schizophrenia (family psychoeducation, cognitive behavioural therapy (CBT) and vocational rehabilitation). CONCLUSION: Institutions should, ideally, be community based, operate a flexible regime, maintain a low density of residents and maximise residents' privacy. For service users with a diagnosis of schizophrenia, specific interventions (CBT, family interventions involving psychoeducation, and supported employment) should be provided through integrated programmes. Restraint and seclusion should be avoided wherever possible and staff should have adequate training in de-escalation techniques. Regular staff supervision should be provided and this should support service user involvement in decision making and positive therapeutic relationships between staff and service users. There should be clear lines of clinical governance that ensure adherence to evidence-based guidelines and attention should be paid to service users' physical health through regular screening

    Continuos clinical remission with biologics in Ulcerative Colitis: the A.U.R.O.R.A. comparative study

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    Comparative trials among biological drugs for the treatment of ulcerative colitis (UC) provided conflicting results. After patent expire of infliximab originator, adalimumab, infliximab biosimilar, golimumab and vedolizumab have been approved in Italy.We compared the efficacy of these four biologics in UC according to the concept of continuous clinical remission (CCR)
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