A Note on Bayesian Model Selection for Discrete Data Using Proper Scoring Rules

We consider the problem of choosing between parametric models for a discrete observable, taking a Bayesian approach in which the within-model prior distributions are allowed to be improper. In order to avoid the ambiguity in the marginal likelihood function in such a case, we apply a homogeneous scoring rule. For the particular case of distinguishing between Poisson and Negative Binomial models, we conduct simulations that indicate that, applied prequentially, the method will consistently select the true model.Comment: 8 pages, 2 figure

Testing the equality of two coefficients of variation: a new Bayesian approach

The use of testing procedures for comparing two coefficients of variation (CVs) of independent populations is not extensively explored in the Bayesian context. We propose to address this issue through a test based on a measure of evidence, the Bayesian Discrepancy Measure, recently introduced in the literature. Computing the Bayesian Discrepancy Measure is straightforward when the CVs depend on a single parameter of the distribution. In contrast, it becomes more difficult when this simplification does not occur since more parameters are involved, requiring often the use of MCMC methods. We derive the Bayesian Discrepancy Measure and the related test by considering a variety of distribution assumptions with multiparametric CVs and apply them to real datasets. As far as we know, some of the examined problems have not yet been covered in the literature

Comparing the safety of COVID-19 vaccines: a geometrical approach

The prompt development of multiple vaccines for the immunization against the world-wide spread of the COVID-19 infection has raised the issue of comparison of their efficacy and of symptomatic effects on the population treated. The different trial reports, made available from the vaccine producers and from the regulatory authorities, analyze some selected systemic reactions reported from patients after the doses received, these are given in a graded scale. In this contribute we propose a geometric way to compare frequency distributions of categorical variables by introducing a distance measure from the best possible scenario in this repartition. The measure proposed is suitable for a direct comparison among the vaccines in terms of the severity of symptomatic reactions

A scientometric analysis of the effect of COVID-19 on the spread of research outputs

The spread of the COVID-19 pandemic in 2020 had a huge impact on the life course of all of us. This rapid spread has also caused an increase in the research production in topics related to different aspects of COVID-19. Italy has been one of the first countries to be massively involved in the outbreak of the disease. In this paper, we present an extensive scientometric analysis of the research production both at global (entire literature produced in the first 2 years after the beginning of the pandemic) and local level (COVID-19 literature produced by authors with an Italian affiliation). Our results showed that US and China are the most active countries in terms of number of publications and that the number of collaborations between institutions varies depending on geographical distance. Moreover, we identified the medical-biological as the field with the greatest growth in terms of literature production. As regards the analysis focused on Italy, we have shown that most of the collaborations follow a geographical pattern, both externally (with a preference for European countries) and internally (two clusters of institutions, north versus center-south). Furthermore, we explored the relationship between the number of citations and variables obtained from the data set (e.g. number of authors). Using multiple correspondence analysis and quantile regression we shed light on the role of journal topics and impact factor, the type of article, the field of study and how these elements affect citations

Tobacco, alcohol and family history of cancer as risk factors of oral squamous cell carcinoma: case-control retrospective study

The aim of the study is to observe retrospectively the correlation between Oral Squamous Cell Carcinoma (OSCC) and risk factors; including tobacco, alcohol and Family History of Cancer (FHC). A total of 478 patients were included retrospectively from the database of the Department of Oral Sciences and Maxillofacial Surgery, Sapienza University of Rome. A Test Group (TG) consisted of 239 patients with a confirmed diagnosis of OSCC. A Control Group (CG) consisted of 239 patients without history and/or diagnosis of oral cancer. The logistic regression models were used to calculate the adjusted Odd Ratios (ORs) associated with alcohol, tobacco and FHC; including the General Family History of Cancer (GFHC) and Family History of Head and Neck Cancer (FHHNC) and their 95% Confidence Intervals (CI). The high rate of tobacco consumption was associated with an OR of 1.035 (95% CI 1.001–1.070) and a statistical significance (p = 0.041). Drinker patients showed a significant risk of developing OSCC (p = 0.05) and the OR was 1.035 (95% CI 1.010–1.061). The GFHC was associated with a marginal risk of OSCC with an OR of 1.095 (95% CI 0.953–1.259), without significance (p = 0.199). The FHHNC showed a notable risk increase with an OR of 1.871 (95% CI 0.902–3.882), without significance (p = 0.092). Alcohol and tobacco may be associated with an increase in the risk of OSCC

Intestinal microbiota sustains inflammation and autoimmunity induced by hypomorphic RAG defects

Omenn syndrome (OS) is caused by hypomorphic Rag mutations and characterized by a profound immunodeficiency associated with autoimmune-like manifestations. Both in humans and mice, OS is mediated by oligoclonal activated T and B cells. The role of microbial signals in disease pathogenesis is debated. Here, we show that Rag2R229Q knock-in mice developed an inflammatory bowel disease affecting both the small bowel and colon. Lymphocytes were sufficient for disease induction, as intestinal CD4 T cells with a Th1/Th17 phenotype reproduced the pathological picture when transplanted into immunocompromised hosts. Moreover, oral tolerance was impaired in Rag2R229Q mice, and transfer of wild-type (WT) regulatory T cells ameliorated bowel inflammation. Mucosal immunoglobulin A (IgA) deficiency in the gut resulted in enhanced absorption of microbial products and altered composition of commensal communities. The Rag2R229Q microbiota further contributed to the immunopathology because its transplant into WT recipients promoted Th1/Th17 immune response. Consistently, long-term dosing of broad-spectrum antibiotics (ABXs) in Rag2R229Q mice ameliorated intestinal and systemic autoimmunity by diminishing the frequency of mucosal and circulating gut-tropic CCR9+ Th1 and Th17 T cells. Remarkably, serum hyper-IgE, a hallmark of the disease, was also normalized by ABX treatment. These results indicate that intestinal microbes may play a critical role in the distinctive immune dysregulation of OS

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

A Bayesian Test for the comparison of two independent populations

In this paper, we propose a testing procedure that allows to compare pa- rameter functions from two independent populations. We address this issue through a test based on the Bayesian Discrepancy Measure, a measure of evidence recently introduced in the literature. This approach is flexible, as it can be adapted to take into account different distributions and different parameter transformations. In ad- dition, this methodology enables us to tackle problems that are not yet covered in the literature

Diurnal and circadian regulation of opsin-like transcripts in the eyeless cnidarian Hydra

Opsins play a key role in the ability to sense light both in image-forming vision and in non-visual photoreception (NVP). These modalities, in most animal phyla, share the photoreceptor protein: an opsin-based protein binding a light-sensitive chromophore by a lysine (Lys) residue. So far, visual and non-visual opsins have been discovered throughout the Metazoa phyla, including the photoresponsive Hydra, an eyeless cnidarian considered the evolutionary sister species to bilaterians. To verify whether light influences and modulates opsin gene expression in Hydra, we utilized four expression sequence tags, similar to two classic opsins (SW rhodopsin and SW blue-sensitive opsin) and two non-visual opsins (melanopsin and peropsin), in investigating the expression patterns during both diurnal and circadian time, by means of a quantitative RT-PCR. The expression levels of all four genes fluctuated along the light hours of diurnal cycle with respect to the darkness one and, in constant dark condition of the circadian cycle, they increased. The monophasic behavior in the L12:D12 cycle turned into a triphasic expression profile during the continuous darkness condition. Consequently, while the diurnal opsin-like expression revealed a close dependence on light hours, the highest transcript levels were found in darkness, leading us to novel hypothesis that in Hydra, an “internal” biological rhythm autonomously supplies the opsins expression during the circadian time. In conclusion, in Hydra, both diurnal and circadian rhythms apparently regulate the expression of the so-called visual and non-visual opsins, as already demonstrated in higher invertebrate and vertebrate species. Our data confirm that Hydra is a suitable model for studying ancestral precursor of both visual and NVP, providing useful hints on the evolution of visual and photosensory systems

New perspectives in bibliometric indicators: Moving from citations to citing authors

We propose a new bibliometric indicator, called citing authors index, to assess the impact and spread of the individual scientific research. With this new index we change the paradigm by focusing the attention to the number of citing authors instead of the mere number of citations. We test this index in the mathematical community by using the MathSciNet database of the American Mathematical Society. An aggregate version of the index is also proposed for the comparison of the performances of different institutions