Spherical orbit closures in simple projective spaces and their normalizations

Let G be a simply connected semisimple algebraic group over an algebraically closed field k of characteristic 0 and let V be a rational simple G-module of finite dimension. If G/H \subset P(V) is a spherical orbit and if X is its closure, then we describe the orbits of X and those of its normalization. If moreover the wonderful completion of G/H is strict, then we give necessary and sufficient combinatorial conditions so that the normalization morphism is a homeomorphism. Such conditions are trivially fulfilled if G is simply laced or if H is a symmetric subgroup.Comment: 24 pages, LaTeX. v4: Final version, to appear in Transformation Groups. Simplified some proofs and corrected minor mistakes, added references. v3: major changes due to a mistake in previous version

A combinatorial smoothness criterion for spherical varieties

We suggest a combinatorial criterion for the smoothness of an arbitrary spherical variety using the classification of multiplicity-free spaces, generalizing an earlier result of Camus for spherical varieties of type $A$.Comment: 14 pages, 2 table

DIETARY PATTERNS AND ESOPHAGEAL CANCER: A POSTERIORI DIETARY PATTERNS IDENTIFIED THROUGH FACTOR ANALYSIS AND CLUSTER ANALYSIS

Background: Because of the complexity of diet and the potential interactions between dietary components, the use of dietary patterns has been proposed, to describe variations in overall dietary intakes in a specific population and to analyze the relationship between diet and cancer risk. In the present work, factor analysis and cluster analysis were used in combination to identify groups of subjects with similar dietary patterns. Patients and methods: We analyzed data from an Italian case\u2013control study, including 304 cases with squamous cell carcinoma of the esophagus and 743 hospital controls. Dietary habits were evaluated using a food frequency questionnaire. A posteriori dietary patterns were identified through principal component factor analysis performed on 28 selected nutrients. A varimax rotation was applied to achieve a simpler loading structure. Nutrients with absolute rotated factor loading greater or equal to 0.63 on a given pattern were used to name the patterns. For each pattern, participants were grouped into categories according to quartile of factor scores among the control population, and the odds ratios (OR) and corresponding 95% confidence intervals (CI) were estimated using unconditional multiple logistic regression models accounting for potential confounding variables. Then, cluster analysis was performed on factor scores obtained from factor analysis. The main analysis was carried out using the k-means method with Euclidean distance. The initial seeds were obtained performing preliminarily a hierarchical method (Ward\u2019s) and cutting the resulting dendrogram at the level corresponding to 6 clusters. Results from the main analysis were compared with those from other clustering solutions identified using the k-means method with Manhattan, Lagrange and Correlation coefficient similarity measure distances and the Partitioning around Medoids method, with both Euclidean and Manhattan distances. The identified clusters were characterized by examining the distribution of several sociodemographic and lifestyle variables, and the average consumption of selected nutrients and food groups, within cluster. The ORs were estimated for each of the identified clusters, and corresponding 95% CIs were obtained referring to the floating absolute risks method. Results: PCFA allowed to identify five major dietary patterns, which explained about 80% of the total variance in the original nutrients. The Animal products and related components pattern (with high factor loadings on calcium, phosphorus, riboflavin, animal protein, saturated fatty acids, cholesterol, and zinc) was positively related to esophageal cancer risk (OR=1.64, 95% CI: 1.06-2.55). The Vitamins and fiber (with high loadings on vitamin C, total fiber, beta-carotene equivalents, soluble carbohydrates, and total folate) and the Other polyunsaturated fatty acids and vitamin D (with high loadings on other polyunsaturated fatty acids, vitamin D, and niacin) were inversely related to esophageal cancer (OR=0.50, 95% CI: 0.32-0.78, and OR=0.48, 95% CI: 0.31-0.74, respectively), while no relationship with this cancer was observed for the Starch-rich (starch, vegetable protein, and sodium) characterized by high loadings on (OR=0.80, 95% CI: 0.50-1.28) and the Other fats (with high loadings on linoleic acid, linolenic acid, and vitamin E) patterns (OR=1.04, 95% CI: 0.67-1.63). The naming of the factors, based on high factor scores characterizing each pattern, was confirmed by the distributions of selected nutrients and food groups. The subsequent cluster analysis, based on differences in the dietary patterns, yielded 6 clusters, one of which (C3) was characterized by the lowest intakes of all nutrients and food groups considered, while the remaining clusters were determined by an extreme value of the dietary patterns, one-by-one. Subjects in the C1 cluster were characterized by the highest values of the Vitamins and fiber pattern, subjects in the C2 cluster had the highest values of the Other polyunsaturated fatty acids pattern, the C4 cluster was characterized by the highest scores of the Animal products and related components, subjects in the C5 cluster had the highest values of the Other fats pattern, the C6 cluster was characterized by the highest scores of the Starch-rich pattern and had the highest intakes of bread, and pasta and rice. Significant inverse relations were observed between the C1, C5 and C6 clusters (OR=0.59, 95% CI:0.40-0.88, OR=0.42, 95% CI:0.20-0.86, and OR=0.60, 95% CI: 0.42-0.86, respectively) \u2013 which were characterized by high values of the Vitamins and fiber, Other fats, and Starch-rich patterns, respectively \u2013 as compared to the C3 cluster. No significant risk was observed for the C2, and C4 clusters (OR=0.76, 95% CI: 0.51-1.13, and OR=1.29, 95% CI: 0.80-2.07). Conclusion: The combined application of factor and cluster analyses, allows to identify key dietary aspects in a specific population, and to obtain mutually exclusive groups of subjects who are similar for these characteristics. The two techniques have limitations that arise from the subjective decisions involved in the analyses. In this application, various alternative options were tried, to check robustness and solution stability. Among these complementary analyses, results from PCFA were compared with those from another principal axis factoring, and those from PCFA analyses performed separately in strata of center and gender, and in randomly generated split samples. Moreover, the internal consistency of the identified patterns was evaluated using the Cronbach\u2019s coefficient alphas. All these checks supported the decisions adopted in the main analyses. As concern cluster analysis, to limit the influence of the starting point, the initial seeds used in the k-means method were obtained performing a hierarchical clustering (Ward\u2019s method) and cutting the corresponding dendrogram at the level k=6. Moreover, some alternative solutions were identified through different methods and distances, yielding comparable clustering solutions. Another limitation of cluster analysis is its sensitivity to the presence of outliers; however, the exclusion of 8 potential outliers did not materially change the results

Nutrient dietary patterns and the risk of laryngeal cancer : an Italian case-control study

Introduction. Several studies have indicated a role of diet in the etiology of laryngeal cancer. Since foods and nutrients tend to be closely related and act synergistically, the pecific effect of each dietary component of interest may be difficult to identify and can be partly confounded by other dietary components. Dietary patterns have thus been proposed as a practical tool to describe the association between diet and cancer, given their ability to capture the variations in overall food intake (Newby, Tucker 2004). A few studies have investigated the role of diet on laryngeal cancer through factor analysis. Aims We applied exploratory principal component factor analysis (PCFA) to identify a posteriori dietary patterns for a multicentric case-control study conducted in Italy on cancer of the larynx. This a posteriori technique allows to integrate several dietary exposures (i.e. foods, food groups, nutrients) into a smaller number of dietary patterns, that are independent from one another and can be evaluated as risk factors in subsequent analysis for the assessment of cancer risk. Methods A case-control study of cancer of the larynx was conducted from 1992 and 2000 in the provinces of Milan and Pordenone, in the Northern Italy. Cases were 460 subjects (415 men, 45 women) admitted to major teaching and general hospitals in the study areas with incident, histologically confirmed squamous cell cancer of the larynx, diagnosed no longer than 1 year before the interview. Controls were 1088 subjects (863 men, 225 women) admitted to the same hospitals for a wide spectrum of acute, non-neoplastic conditions, unrelated to smoking or alcohol drinking, or long term modifications of diet. The subjects\u2019 diet was assessed using a valid and reproducible food frequency questionnaire (FFQ) including 78 foods and beverages, as well as a range of the most common Italian recipes. Subjects were asked to indicate the average weekly consumption for each dietary item; intakes lower than once a month were coded as 0.5 per week. To estimate the intake of various nutrients, an Italian food composition database was used. We performed an exploratory PCFA on a selected set of 28 major macro- and micro-nutrients. We preliminarily evaluated the correlation matrix to determine if it was factourable, trough visual inspection and statistical procedure (Bartlett\u2019s test of sphericity). Moreover, we evaluated the Kaiser-Meyer-Olkin measure and individual measures of sampling adequacy (Kaiser, 1974). We chose the number of factors to retain based on the following criteria: factor eigenvalue greater than 1, scree plot examination and factor interpretability. We applied a varimax rotation to the factor loadings matrix to achieve a simpler and more interpretable solution. We used nutrients with rotated factor loading greater or equal to 0.63 on a given factor to name the pattern. Factor scores were defined for each subject and for each factor following the weighted least square method. They indicate the degree to which each subject\u2019s diet conforms to one of the identified patterns. To examine the robustness of the identified dietary patterns, we performed a principal axis factor analysis on the standardized nutrients and a maximum likelihood factor analysis after logarithmic transformation of the original nutrients. We calculated factor scores referring to the multiple regression method and standardizing the results. The correlations between scores referring to the same factor calculated with different methods were equal to 1 for all the comparisons. We also performed factor analysis separately within male and female subsamples and within different centers. All these checks yielded dietary patterns consistent with PCFA the ones obtained on the overall sample. To assess the reliability and refine the identified factors, we evaluated the internal consistency of those nutrients with a loading greater than 0.40 using standardized Cronbach\u2019s coefficient alpha. We calculated coefficient alphas for each factor and coefficient alphas when item deleted (Cronbach, 1951). To confirm the internal reproducibility of the identified patterns, individuals were randomly placed into one of two equally sized groups, and PCFA was performed separately in both subsamples. For each factor, we grouped participants into three categories according to quintiles of factor scores among the control population, and estimated the odds ratio and corresponding 95% confidence intervals using unconditional multiple logistic regression models, including all the factors simultaneously. The model was adjusted for sex, age, study center, education, body mass index, physical activity, tobacco smoking, and alcohol drinking. Results Five factors were retained according to the defined criteria. These factors explained 79% of the total variance of the original nutrients. The first pattern, named Animal products, had the greatest loadings on calcium, phosphorus, riboflavin, animal protein, saturated fatty acids, zinc, and cholesterol. The second pattern, named Starch-rich, had the greatest loadings on starch, vegetable protein, and sodium. The third pattern, named Vitamins and fiber, had the greatest loadings on vitamin C, total fiber, beta-carotene equivalents, and total folate. The fourth pattern, named Seed oils, had the greatest loadings on linoleic acid, vitamin E, and linolenic acid. The fifth pattern, named Fish-rich, had the greatest loadings on other polyunsaturated fatty acids, and vitamin D. A direct association was observed between the Animal products pattern and laryngeal cancer (OR=1.94, 95% CI: 1.39-2.70). A borderline direct association was observed between the Starch-rich pattern and laryngeal cancer (OR=1.30, 95% CI: 0.93-1.81). An inverse relationship was observed between the Vitamins and fiber pattern and laryngeal cancer (OR=0.56, 95% CI: 0.41-0.76). No relationship was evident between the Seed oils pattern and laryngeal cancer (OR=0.98, 95% CI: 0.70-1.37). A direct association was found between the Fish-rich pattern and the laryngeal cancer (OR=2.09, 95% CI: 1.51-2.90). Conclusions The role of dietary habits on the risk of laryngeal cancer was evaluated through exploratory PCFA on 28 major nutrients of interest. We identified 5 major dietary patterns, explaining about 80% of the total variance of the original nutrients. Our results indicated that the Animal products and Fish-rich patterns are potentially unfavourable indicators of risk for laryngeal cancer, while the Vitamins and fiber pattern is inversely related to laryngeal cancer

Combining Revealed and Stated Preferences to design a new urban park in a metropolitan area of North-Western Italy

Inclusive and participatory decision-making is a sustainable option for governments and decision-makers to support real transformation and planning of policies and actions. Investigating and gathering the various views and opinions of stakeholders and citizens is particularly effective because it opens up a range of possibilities in co-constructing the city of the future. Among urban areas requiring planning, Urban Green Infrastructures (UGIs) represent spaces designed to improve the character of neighborhoods, as well as to increase the well-being of users. To achieve these goals, planners should adopt a design approach in which UGIs projects are shaped by local community concerns rather than by market conventions in urban design. Focusing on green recreational areas, this study employs an integrated approach combining Revealed (RP) and Stated Preferences (SP) to investigate citizens' preferences regarding urban parks. In particular, the experiment combines Travel Cost Method (TCM) and Discrete Choice Experiment (DCE) for supporting a requalification project in an ex-industrial area of Turin (Italy). In this way, it was possible to understand which facilities can contribute to increasing the citizens’ well-being and the overall efficiency of the UGIs provision and maintenance. The proposed methodology represents an operational and replicable procedure to support different renewal projects in which citizens' opinions are crucial for developing long-term sustainable socio-ecological plans and actions

Antibiotic De-Escalation in Emergency General Surgery

Background. Antibiotic treatment in emergency general surgery (EGS) is a major challenge for surgeons, and a multidisciplinary approach is necessary in order to improve outcomes. Intra-abdominal infections are at high risk of increased morbidity and mortality, and prolonged hospitalization. An increase in multi-drug resistance bacterial infections and a tendency to an antibiotic overuse has been described in surgical settings. In this clinical scenario, antibiotic de-escalation (ADE) is emerging as a strategy to improve the management of antibiotic therapy. The objective of this article is to summarize the available evidence, current strategies and unsolved problems for the optimization of ADE in EGS. Methods. A literature search was performed on PubMed and Cochrane using “de-escalation”, “antibiotic therapy” and “antibiotic treatment” as research terms. Results. There is no universally accepted definition for ADE. Current evidence shows that ADE is a feasible strategy in the EGS setting, with the ability to optimize antibiotic use, to reduce hospitalization and health care costs, without compromising clinical outcome. Many studies focus on Intensive Care Unit patients, and a call for further studies is required in the EGS community. Current guidelines already recommend ADE when surgery for uncomplicated appendicitis and cholecystitis reaches a complete source control. Conclusions. ADE in an effective and feasible strategy in EGS patients, in order to optimize antibiotic management without compromising clinical outcomes. A collaborative effort between surgeons, intensivists and infectious disease specialists is mandatory. There is a strong need for further studies selectively focusing in the EGS ward setting

Sepsis Team Organizational Model to Decrease Mortality for Intra-Abdominal Infections: Is Antibiotic Stewardship Enough?

Introduction. Sepsis is an overwhelming reaction to infection with significant morbidity, requiring urgent interventions in order to improve outcomes. The 2016 Sepsis-3 guidelines modified the previous definitions of sepsis and septic shock, and proposed some specific diagnostic and therapeutic measures to define the use of fluid resuscitation and antibiotics. However, some open issues still exist. Methods. A literature research was performed on PubMed and Cochrane using the terms “sepsis” AND “intra-abdominal infections” AND (“antibiotic therapy” OR “antibiotic treatment”). The inclusion criteria were management of intra-abdominal infection (IAI) and effects of antibiotic stewardships programs (ASP) on the outcome of the patients. Discussion. Sepsis-3 definitions represent an added value in the understanding of sepsis mechanisms and in the management of the disease. However, some questions are still open, such as the need for an early identification of sepsis. Sepsis management in the context of IAI is particularly challenging and a prompt diagnosis is essential in order to perform a quick treatment (source control and antibiotic treatment). Antibiotic empirical therapy should be based on the kind of infection (community or hospital acquired), local resistances, and patient’s characteristic and comorbidities, and should be adjusted or de-escalated as soon as microbiological information is available. Antibiotic Stewardship Programs (ASP) have demonstrated to improve antimicrobial utilization with reduction of infections, emergence of multi-drug resistant bacteria, and costs. Surgeons should not be alone in the management of IAI but ideally inserted in a sepsis team together with anaesthesiologists, medical physicians, pharmacists, and infectious diseases specialists, meeting periodically to reassess the response to the treatment. Conclusion. The cornerstones of sepsis management are accurate diagnosis, early resuscitation, effective source control, and timely initiation of appropriate antimicrobial therapy. Current evidence shows that optimizing antibiotic use across surgical specialities is imperative to improve outcomes. Ideally every hospital and every emergency surgery department should aim to provide a sepsis team in order to manage IAI

Risk factors for breast cancer in a cohort of mammographic screening program : a nested case-control study within the FRiCaM study

Breast cancer is the most common cancer diagnosis and the leading cause of cancer death among women in the world, and differences across populations indicate a role of hormonal, reproductive and lifestyle factors. This study is based on a cohort of 78,050 women invited to undergo a mammogram by Local Health Authority of Milan, between 2003 and 2007. We carried out a nested case\u2013control study including all the 3303 incident breast cancer cases diagnosed up to 2015, and 9909 controls matched by age and year of enrollment. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were estimated using logistic regression models. The ORs were 0.88 (95% CI: 0.78\u20130.98) for an age at menarche 6514 years and 1.39 (95% CI: 1.07\u20131.81) for an age of 30 years or older at first pregnancy. Body mass index (BMI) was positively associated with breast cancer risk in women older than 50 years (OR = 1.89, 95% CI: 1.54\u20132.31, for BMI 6530 vs. 75% vs. adipose tissue). The ORs were 1.67 (95% CI: 1.47\u20131.89) and 2.04 (95% CI: 1.38\u20133.00) for one first\u2010degree relative and two or more relatives affected by breast cancer, respectively. Our study confirms the role of major recognized risk factors for breast cancer in our population and provides the basis for a stratification of the participants in the mammographic screening according to different levels of ris

Nutrient dietary patterns and the risk of colorectal cancer : a case-control study from Italy

The role of diet on colorectal cancer has been largely investigated in terms of foods and nutrients, but rarely in terms of dietary patterns. We evaluated the relationship between major dietary patterns and colorectal cancer in an Italian case-control study including 1,225 patients with cancer of the colon, 728 patients with cancer of the rectum, and 4,154 controls, hospitalized for acute non-neoplastic diseases. Dietary habits were investigated through a validated food-frequency questionnaire. We identified dietary patterns on a selected set of nutrients through principal component factor analysis. Odds ratios (OR) and 95% confidence intervals (CI) for both cancer were estimated using unconditional multiple logistic regression models on quintiles of factor scores. We identified 4 major dietary patterns named Animal products, Vitamins and fiber, Unsaturated fats, Strach-rich. No significant association was observed between Animal products pattern and cancer of the colon (OR=0.97, 95% CI: 0.78-1.20, for the highest quintile of factor scores as compared to the lowest), and rectum (OR=1.26, 95% CI: 0.97-1.64). An inverse relationship was found for the Vitamins and fiber pattern and cancer of the rectum (OR=0.68, 95% CI: 0.52-0.88), but not for that of the colon (OR=0.90, 95% CI: 0.73-1.12). A direct association was observed between the Starch-rich pattern and both cancer of the colon (OR=2.10, 95% CI: 1.64-2.68) and rectum (OR=1.93, 95% CI: 1.42-2.63). An inverse association was found for the Unsaturated fats pattern and cancer of the colon (OR=0.89, 95% CI: 0.72-1.10), while no significant association was found for the Unsaturated fats pattern and rectal cancer (OR=1.33, 95% CI: 1.02-1.74)

Daylight saving time and acute myocardial infarction: a meta-analysis

Background The current evidence on the effects of daylight saving time (DST) transitions on major cardiovascular diseases is limited, and available results are conflicting. We carried out the first meta-analysis aimed at evaluating the risk of acute myocardial infarction (AMI) following DST transitions. Methods We searched MedLine and Scopus up to December 31, 2018, with no language restriction, to retrieve cohort or case-control studies evaluating AMI incidence among adults (≥18y) in the week following spring and/or autumn DST shifts versus control periods. A summary relative risk of AMI was computed after: (1) spring, (2) autumn, (3) both transitions considered together versus control weeks. Stratified analyses were performed by gender and age. Data were combined using a generic inverse-variance approach. Results Seven studies (>115,000 subjects) were included in the analyses. A significantly higher risk of AMI (Odds Ratio: 1.03; 95% CI: 1.01-1.06) was observed in the two weeks following spring or winter DST transitions. The risk increase was however significant only after the spring shift (OR: 1.05; 1.02-1.07), while AMI incidence in the week after winter DST transition was comparable to control periods (OR 1.01; 0.98-1.04). No substantial differences by age or gender emerged. Conclusions The risk of AMI increases modestly but significantly following DST transitions, supporting the proposal of DST shifts discontinuation. Additional studies fully adjusting for potential confounders are required to confirm the present findings