Threshold-based Naïve Bayes classifier

The Threshold-based Naive Bayes (Tb-NB) classifier is introduced as a (simple) improved version of the original Naive Bayes classifier. Tb-NB extracts the sentiment from a Natural Language text corpus and allows the user not only to predict how much a sentence is positive (negative) but also to quantify a sentiment with a numeric value. It is based on the estimation of a single threshold value that concurs to define a decision rule that classifies a text into a positive (negative) opinion based on its content. One of the main advantage deriving from Tb-NB is the possibility to utilize its results as the input of post-hoc analysis aimed at observing how the quality associated to the different dimensions of a product or a service or, in a mirrored fashion, the different dimensions of customer satisfaction evolve in time or change with respect to different locations. The effectiveness of Tb-NB is evaluated analyzing data concerning the tourism industry and, specifically, hotel guests' reviews from all hotels located in the Sardinian region and available on Booking.com. Moreover, Tb-NB is compared with other popular classifiers used in sentiment analysis in terms of model accuracy, resistance to noise and computational efficiency

The Magnetic Distortion Calibration System of the LHCb RICH1 Detector

The LHCb RICH1 detector uses hybrid photon detectors (HPDs) as its optical sensors. A calibration system has been constructed to provide corrections for distortions that are primarily due to external magnetic fields. We describe here the system design, construction, operation and performance.Comment: 9 pages, 14 figure

Addressing the effect of concern with COVID-19 threat on prejudice towards immigrants: The sequential mediating role of need for cognitive closure and desire for cultural tightness

The link between threat and anti-immigrant prejudice is well-established. Relatedly, recent research has also shown that situational threats (such as concern with COVID-19 threat) increase anti-immigrant prejudice through the mediating role of desire for cultural tightness. This study aims to further our understanding of the psychological processes underlying the relation between concern with COVID-19 threat and increased negative attitudes towards immigrants by considering the mediational role of an individual epistemic motivation (i.e., the need for cognitive closure). A study was conducted on a large sample of Italian respondents covering all the Italian regions. Findings revealed that high concern with COVID-19 threat led to increased negative attitudes towards immigrants through the sequential mediating role of higher need for cognitive closure, leading in turn to higher desire for cultural tightness. Implications of these findings for a timely contextualized study of anti-immigrant prejudice will be highlighted

Alcohol-related behaviour in freshmen university students in Sardinia, Italy

This study aims to provide a picture of University of Cagliari students’ alcohol-related behaviour and to explore factors associated with it. Data were collected by administering a questionnaire to 992 freshmen university students from different programs consisting of twelve closed questions, including three questions from the Alcohol Use Disorders Identification Test for Consumption (AUDIT-C short form). Three subgroups of alcohol-related behaviour were distinguished (risky drinkers, social drinkers and abstainers). In order to explore factors associated with patterns of alcohol consumption, a multivariate logistic regression was performed. The prevalence of risky drinkers was 35%. A binge-drinking behaviour at least once in the last twelve months was declared by 65% (more widespread in men and in students living away from their parents). Risky consumption is significantly associated with age of onset of alcohol use, living away from parents’ home, drinking outside meals and attending health courses. Regarding the levels of daily alcohol consumption perceived as a health risk, 66% of men and 88% of women indicate values higher than those recommended. The results underline the need for tailored prevention measures. University could be a promising setting to implement actions according to a health promotion perspective, to empower students to control their alcohol consumption

Association of the HLA-A2, Cw2, B27, S31, DR2 haplotype with Ankylosing Spondylitis. A possible role of non-B27 factors in the disease

With the aim of searching for HLA haplotypes and non-B27 allele frequency variations in Sardinian AS patients, HLA-A, B, Cw, DR, DQ and Bf, C4A and C4B typing and haplotype assignment was carried out in the families of 25 AS patients and in 44 healthy individuals, all B27 heterozygotes. In the AS patients a significant increase of the A2, Cw2, B27, DR2, DQ1 haplotype was found. This depends only partially on the linkage disequilibrium existing in the Sardinian population between B27 and the other alleles of this haplotype, and rather seems to be due to a primary association of Cw2 and DR2 alleles with AS. Preliminary data seem to show that this haplotype bears the S3l complotype and the ORB1 * 1601 allele both in the AS patients and in the healthy controls. The pathogenetic implications of these findings are discussed

Preoperative assessment of cardiovascular risk in patients undergoing noncardiac surgery: The Orion study

In patients undergoing noncardiac surgery risk indices can estimate patients' perioperative risk of major cardiovascular complications. The indexes currently in use were derived from observational studies that are now outdated with respect to the current clinical context. We undertook a prospective, observational, cohort study to derive, validate, and compare a new risk index with established risk indices. We evaluated 7335 patients (mean age 63±13 years) who underwent noncardiac surgery. Based on prospective data analysis of 4600 patients (derivation cohort) we developed an Updated Cardiac Risk Score (UCRS), and validated the risk score on 2735 patients (validation cohort). Four variables (i.e. the UCRS) were significantly associated with the risk of a major perioperative cardiovascular events: high-risk surgery, preoperative estimate glomerular filtration rate <30 ml/min/1.73 m2, age ≥75 years, and history of heart failure. Based on the UCRS we created risk classes 1,2,3 and 4 and their corresponding 30-day risk of a major cardiovascular complication was 0.8% (95% confidence interval [CI] 0.5-1.7), 2.5 (95% CI 1.6-5.6), 8.7 (95% CI 5.2-18.9) and 27.2 (95% CI 11.8-50.3), respectively. No significant differences were found between the derivation and validation cohorts. Receiver operating characteristic (ROC) curves demonstrate a high predictive performance of the new index, with greater power to discriminate between the various classes of risk than the indexes currently used. The high predictive performance and simplicity of the UCRS make it suitable for wide-scale use in preoperative cardiac risk assessment of patients undergoing noncardiac surgery

A network perspective to the measurement of sense of coherence (SOC): an exploratory graph analysis approach

The measurement of sense of coherence (SOC) has received attention for more than three decades. Despite the extensive use of SOC-13, there is still a long debate regarding its dimensionality structure. Recently, there has been an increasing use of network modeling as a valid alternative to latent-variable modeling. This study proposes an exploratory approach to the structure of SOC-13 by adopting a network perspective. The network structure was estimated with a Gaussian Graphical Model, and Exploratory Graph Analysis (EGA) was used to inspect network dimensionality. We fit and compared the unidimensional, first- and second-order confirmatory factor analysis (CFA), bifactor-CFA, and structure derived from EGA. Our results showed unacceptable fit values for the CFA models, suggesting that SOC-13 is not unidimensional. Inspection of the estimated network suggested that the SOC-13 items emerged as a dynamic system of mutually interacting nodes that formed three distinct clusters of items (communities) that are not those defined in the literature. EGA identified three communities of items: the first community was characterized by comprehensibility and manageability items, the second community was characterized by comprehensibility and manageability items, and the third dimension was characterized by all meaningfulness items and one comprehensibility item. Our study presented a novel perspective in investigating the structure of SOC-13 that strengthens the assumption that SOC should be conceptualized as a complex system of cognitive (comprehensibility), behavioral (manageability), and motivational dimensions (meaningfulness) that are deeply linked and not necessarily distinct