197,709 research outputs found
1H-NMR and Photo-CIDNP Spectroscopies show a possible Role for Trp23 and Phe31 in Nucleic Acid Binding by P2 Ribonuclease from the archaeon Sulfolobus solfataricus
No full textInvestigations were performed on recombinant ribonuclease P2 from Sulfolobus solfataricus, previously cloned and expressed in Escherichia coli [Fusi, P., Grisa, M., Mombelli, E., Consonni, R., Tortora, P. and Vanoni, M. (1995) Gene 154, 99-103]. NMR and photo-CIDNP spectroscopies showed that the enzyme possesses an aromatic cluster consisting of Phe5, Tyr7, Phe31 and Tyr33 while Trp23 is fully exposed to solvent. Phe31, Tyr33 and Trp23 are located within a triple stranded antiparallel beta-sheet, each one being part of an amino acid stretch matching consensus sequences for RNA binding. Phe31 and Trp23 are exposed to and specifically interact with a flavin dye used as a model ligand, with a topology reminiscent of that found in several eubacterial and eukariotic RNA-binding proteins
Comment on 'The latency period of mesothelioma among a cohort of British asbestos workers (1978-2005)': methodological problems with case-only survival analysis.
No full textEnhanced objective Bayesian testing for the equality of two proportions
No full textWe develop a new class of prior distributions for Bayesian comparison of nested models, which we call intrinsic moment priors, by combining the well-established notion of intrinsic prior with the recently introduced idea of non-local priors, and in particular of moment priors. Specifically, we aim at testing the equality of two proportions, based on independent samples, and thus focus on discrete data models. Given two nested models, each equipped with a default prior, we first construct a moment prior under the larger model. In this way, the asymptotic learning behavior of the Bayes factor is strengthened, relative to currently used local priors, when the smaller model holds; remarkably, this effect is already apparent for moderate sample sizes. On the other hand, the symptotic learning behavior of the Bayes factor when the larger model holds is unchanged. However, without appropriate tuning, a moment prior does not provide enough evidence for the larger model when the sample size is small and the data only moderately support the smaller one. For this reason, we apply to the moment prior an intrinsic prior procedure, which amounts to pulling the moment prior towards the subspace specified by the smaller model; we provide general guidelines for determining the training sample size necessary to implement this step. Thus, by joining the virtues of moment and intrinsic priors, we obtain an enhanced objective Bayesian testing procedure: i) our evidence for small samples is broadly comparable to that given by current objective methods; ii) we achieve a superior learning performance as the sample size increases (when the smaller model holds). We first illustrate our methodology in a running Bernoulli example, where we test a sharp null hypothesis, then we implement our procedure to test the equality of two proportions. A detailed analysis of the properties of our method, including a comparison with standard intrinsic priors, is presented together with an application to a collection of real-world 2 by 2 tables involving a sensitivity analysis and a crossvalidation study.<br/
Fandom politici e social media l’affettività nella fase preelettorale
No full textThis article analyses political fandom in Italy through the cases of Giorgia
Meloni, Giuseppe Conte, Elly Schlein, and Matteo Salvini. Based on 7,622 social
media posts from April to June 2024 (during the Italian campaign for the European
elections), the study examines affective expressions toward leaders to assess whether
they reflect structured fandoms, spontaneous participation, or orchestrated strategies. It focuses on the strategic use of emotions during the electoral campaign. Using
a mixed-methods approach, the article offers an interpretive lens on emerging forms of political participation in today’s digital ecosystem
Expected posterior priors for model comparison in a class of discrete graphical models.
No full textThe implementation of the Bayesian paradigm to model comparison can be problematic. In
particular, prior distributions on the parameter space of each candidate model require special
care. While it is well known that improper priors cannot be routinely used for Bayesian model
comparison, we claim that also the use of proper conventional priors under each model should
be regarded as suspicious, especially when comparing models having different dimensions.
The basic idea is that priors should not be assigned separately under each model; rather they
should be related across models, in order to acquire some degree of compatibility, and thus
allow fairer and more robust comparisons. In this connection, the intrinsic prior as well as
the expected posterior prior (EPP) methodology represent a useful tool. In this paper we develop
a procedure based on EPP to perform Bayesian model comparison for discrete undirected
decomposable graphical models, although our method could be adapted to deal also with directed
acyclic graph models. We present two possible approaches. One based on imaginary
data, and one which makes use of a limited number of actual data. The methodology is illustrated
through the analysis of a 2 × 3 × 4 contingency table
L'urbanistica e la città storica italiana fra le due guerre / 'Corpo a corpo': il progetto razionalista per via Roma a Bologna, 1936-38
No full textRischi igienico-sanitari legati all’assistenza odontoiatrica, nella città di Milano - indagine questionaria
No full textBACKGROUND: Aim of this investigation is to identify possible sanitary risks connected with the practice of dentistry and to draw up guidelines which may help all those who work in this field. METHODS: Between April and July 1998, we distributed 231 questionnaires to public and private dental offices in Milan, to evaluate dentists' knowledge of sanitary risks in their practices. One hundred and sixteen of the 231 distributed questionnaires were returned. All the dentists contacted, used protective measures such as gloves, masks, glasses, and high-speed aspirators. RESULTS: Survey responses indicated that the most readily transmittable infectious diseases in dentist's practices are, in order of importance, hepatitis, AIDS, airborne diseases, and herpes. Surgery, endodontics, and the use of sharp instruments most likely lead to transmission of pathogens in both patients and dentists. Dentist's knowledge of out-patient treatment is good whereas their knowledge of the use of disinfectants for dental equipment is poor. CONCLUSIONS: The latter suggests the utility of continuing education in this critical aspect of the practice of dentistry
Suscettibilità all'innesco di morfologie di corrosione localizzata dell'acciaio inossidabile duplex SAF 2205 in soluzioni neutre contenenti ioni bromuro
No full textThe susceptibility to localized corrosion of duplex stainless steel SAF 2205 in neutral aqueous solutions containing bromide ions was investigated by means of potentiodynamic cyclic polarization curves. SAF 2205 were previously subjected to a solubilization heat treatment at 1080 °C for 30 minutes to allow the relaxation of grains. Tests were performed at 25 °C under nitrogen atmosphere in NaBr solutions at different concentrations. The pitting potential Epit was found to vary linearly with the logarithm of the concentration of bromide ions. At bromide content higher than 0.01 M a marked hysteresis was observed. Pit distribution was strictly related to bromide content in solution and increased with concentration. The behaviour of SAF 2205 in bromide environment is different than in chloride. In chloride, the material showed a complete passive behaviour also at temperature higher than room temperature, with no corrosion damages except for light crevice corrosion. In bromide the behaviour was completely different and it was a function of ion concentration and material microstructure. To elucidate the effect of ferrite/austenite ratio on the pitting initiation and propagation, the SAF 2205 was subjected to solubilization heat treatments at different times and temperatures. The corrosion attack started preferentially in the ferritic grains. However this specificity decreased with the increase of solubilization temperature and the material showed an improved resistance to localized corrosion. The performance of SAF 2205 was also evaluated in comparison with two austenitic steels (AISI 304 e AISI 304L) and a first generation duplex (AISI 329). In spite of difference in microstructure, the two austenitic steel and AISI 329 showed a similar behaviour, with a pitting potential around 0.3 V. As a general rule, SAF 2205 showed higher pitting potential and better performances towards localized corrosion
Medical Infographics: Resemiotization Strategies in Specialized Discourse
No full textThis chapter addresses the spreading genre of digital infographics, i.e., the conflation of visual and verbal language in the graphic visualization of specific sets of data, information and knowledge, so as to facilitate, accelerate and disseminate specialized cognition processes throughout a digitally competent global audience. Originating from 19th-century economic cartography, military strategy and statistics, and actualizing what C.S. Peirce tagged as a ‘supersign’ (an artefact combining different sign systems such as symbols, icons and indexes), infographic textuality pivots on multi-literacy strategies, allowing large amounts of complex information to be systematized and presented synoptically. By activating multi-cognitive skills through the simultaneous use of visual elements, verbal contents and specialized knowledge frameworks, infographics is nowadays used for a variety of disciplinary dissemination processes. This contribution deals in particular with infographics in the specialized domain of medical knowledge. The resemiotization process inherent to infographics can be ranked as a major strategy for today’s medical communication, especially for the purpose of drawing and validating the epistemic norms of coherence and verification that define evidence-based clinical knowledge, both within and outside the scientific community. The intersemiotic presentation of evidence proves crucial in the epistemological construction of medical discourse. Within the linguistic framework provided by Systemic Functional Grammar metafunctions, and drawing from multimodal analysis, social semiotics, and medical discourse analysis, this chapter investigates how and to what extent medical communication can be shaped by the emergence of new digital genres
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