Emergence of chaotic behaviour in linearly stable systems

Strong nonlinear effects combined with diffusive coupling may give rise to unpredictable evolution in spatially extended deterministic dynamical systems even in the presence of a fully negative spectrum of Lyapunov exponents. This regime, denoted as ``stable chaos'', has been so far mainly characterized by numerical studies. In this manuscript we investigate the mechanisms that are at the basis of this form of unpredictable evolution generated by a nonlinear information flow through the boundaries. In order to clarify how linear stability can coexist with nonlinear instability, we construct a suitable stochastic model. In the absence of spatial coupling, the model does not reveal the existence of any self-sustained chaotic phase. Nevertheless, already this simple regime reveals peculiar differences between the behaviour of finite-size and that of infinitesimal perturbations. A mean-field analysis of the truly spatially extended case clarifies that the onset of chaotic behaviour can be traced back to the diffusion process that tends to shift the growth rate of finite perturbations from the quenched to the annealed average. The possible characterization of the transition as the onset of directed percolation is also briefly discussed as well as the connections with a synchronization transition.Comment: 30 pages, 8 figures, Submitted to Journal of Physics

Can bayesian models play a role in dental caries epidemiology? Evidence from an application to the BELCAP data set

ObjectivesThe aim of this study was to show the potential of Bayesian analysis in statistical modelling of dental caries data. Because of the bounded nature of the dmft (DMFT) index, zero-inflated binomial (ZIB) and beta-binomial (ZIBB) models were considered. The effects of incorporating prior information available about the parameters of models were also shown. MethodsThe data set used in this study was the Belo Horizonte Caries Prevention (BELCAP) study (Bohning etal. (1999)), consisting of five variables collected among 797 Brazilian school children designed to evaluate four programmes for reducing caries. Only the eight primary molar teeth were considered in the data set. A data augmentation algorithm was used for estimation. Firstly, noninformative priors were used to express our lack of knowledge about the regression parameters. Secondly, prior information about the probability of being a structural zero dmft and the probability of being caries affected in the subpopulation of susceptible children was incorporated. ResultsWith noninformative priors, the best fitting model was the ZIBB. Education (OR=0.76, 95% CrI: 0.59, 0.99), all interventions (OR=0.46, 95% CrI: 0.35, 0.62), rinsing (OR=0.61, 95% CrI: 0.47, 0.80) and hygiene (OR=0.65, 95% CrI: 0.49, 0.86) were demonstrated to be factors protecting children from being caries affected. Being male increased the probability of being caries diseased (OR=1.19, 95% CrI: 1.01, 1.42). However, after incorporating informative priors, ZIB models' estimates were not influenced, while ZIBB models reduced deviance and confirmed the association with all interventions and rinsing only. DiscussionIn our application, Bayesian estimates showed a similar accuracy and precision than likelihood-based estimates, although they offered many computational advantages and the possibility of expressing all forms of uncertainty in terms of probability. The overdispersion parameter could expound why the introduction of prior information had significant effects on the parameters of the ZIBB model, while ZIB estimates remained unchanged. Finally, the best performance of ZIBB compared to the ZIB model was shown to catch overdispersion in data

Direct-acting antivirals and visceral leishmaniasis: A case report

Background: Visceral leishmaniasis is a vector-borne parasitic disease caused by protozoa belonging to the genus Leishmania. The clinical presentation of visceral leishmaniasis strictly depends on the host immunocompetency, whereas depressive conditions of the immune system impair the capability to resolve the infection and allow reactivation from sites of latency of the parasite. Case presentation: We describe a case of visceral leishmaniasis (VL) that occurred in a patient with chronic hepatitis C treated with direct-acting antiviral drugs (DAA). The hypothesized mechanism is the alteration of protective inflammation mechanisms secondary to DAA therapy. Downregulation of type II and III IFNs, their receptors, which accompany HCV clearance achieved during treatment with sofosbuvir and ribavirin might have a negative impact on a risk for reactivation of a previous Leishmania infection. We know indeed that IFN-\u3b3 is important to enhance killing mechanisms in macrophages, which are the primary target cells of Leishmania. Conclusion: Since VL is endemic in Sicily as well as in other countries of the Mediterranean basin, physicians should be aware of the possible unmasking of cryptic Leishmania infection by DAAs

Factors influencing flu vaccination in nursing students at Palermo University

Introduction. The purpose of this study was to ascertain the determinants of nursing students' compliance with flu vaccination. Methods. In this cross-sectional study, an anonymous paper questionnaire was administered to students attending the 3-year nursing course at the University of Palermo. Adjusted Odds Ratios (aOR) are presented. Results. 403 nursing students (65% female) completed the questionnaire (response rate 98.5%). The average age of the respondents was 22.0 years (SD ± 3.04). The dependent variable: "In the next season, do you intend to be vaccinated against flu? Yes", displayed a statistically significant association with the following independent variables: "year of study: second" (aOR 2.66), "year of study: third" (aOR 1.72), "Perceived health status: medium-high" (aOR 6.61), "Did you get vaccinated against seasonal flu last year? Yes" (aOR 22.47). Conclusions. Although nursing students are not yet health professionals, they spend part of their time in health facilities for their clinical training and will be the health workers of the future. Involving nursing students in influenza vaccination campaigns can also help them take better care of themselves and their patients

Determinants associated with obesity and physical activity in the public and private schools of the city of palermo

Introduction: Obesity is a medical condition associated with premature death and it is a risk factor for many chronic diseases. In this context, performing a regular physical activity promotes a healthy lifestyle, with significant health benefits. The aim of the study was to investigate behaviors that increase the risk of obesity and the determinants that encourage physical activity among adolescents. Materials and methods: The HBSC (Health Behavior in School-aged Children) questionnaire was administered to students in Palermo's private and public schools. For the sampling of public schools the protocol of the HBSC Surveillance System was followed; for the private ones it was opportunistic. Results: Private school students are more likely to exercise more than 3 days per week (OR 1.58) and are more likely to exercise more than 2 times a week (OR 2.08). Obese students in private schools in Palermo are more likely to perform physical activity for less than 3 days a week (OR 3.52) and a higher risk of not having breakfast (OR 10.11) and a snack between main meals (OR 3.82) every day. For all the schools examined, it emerged that obese subjects are more likely not to consume fruit (OR 3.13), to stay more than 6 hours a day in front of PCs and video games (OR 3.24) and more than 2 hours a day in front of TV (OR 3.79). Male students are more likely to perform physical activity for more than 3 days per week (OR 1.48) and intense physical activity at least 2 times per week (OR 1.76) Conclusions: It is necessary to intervene early with training on school and family in order to promote correct and responsible food choices and increase the level of physical activity among students. Therefore prevention interventions must be an integral part of coherent strategies based on tests of agreed effectiveness in order to minimize the risk linked to the development of diseases

Abemaciclib: safety and effectiveness of a unique cyclin-dependent kinase inhibitor

Introduction: The discovery and the clinical availability of novel cyclin-dependent kinases 4 and 6 inhibitors have profoundly changed the therapeutic scenario of metastatic hormone receptor-positive breast carcinoma. Among these inhibitors, abemaciclib can induce potent and sustained cell cycle arrest and immune system stimulation. Areas covered: This review summarizes the safety profile and clinical efficacy data on abemaciclib alone or in combination with aromatase inhibitors or fulvestrant in metastatic hormone receptor-positive breast carcinoma. The management of patients treated with abemaciclib is the object of this paper. Expert opinion: As shown in phase 2 and 3 clinical trials on efficacy and tolerability, abemaciclib is a potentially convenient, safe, and effective agent for the treatment of patients with advanced hormone receptor-positive patients. Orally administered abemaciclib in combination with aromatase inhibitors or fulvestrant has the potential to allow significant improvement in survival outcomes, quality of life, response rate, and duration of response even in poor prognosis subgroups. Adequate patients’ information, clinical selection, and prompt, proactive management of side effects are mandatory

Comparison between adenosine triphosphate bioluminescence and aerobic colony count to assess surface sanitation in the hospital environment

Background: Adenosine triphosphate bioluminescence produced by the firefly luciferase has been successfully introduced to verify cleaning procedures in the food industry according to the Hazard Analysis Critical Control Point program. Our aim was to evaluate the reliability of bioluminescence as a tool to monitor the effectiveness of sanitation in healthcare settings, in comparison with the microbiological gold standard. Methods: 614 surfaces of various material were randomly sampled in Policlinico University Hospital units in Palermo, Italy, to detect adenosine triphosphate bioluminescence and aerobic colony count. Linear regression model and Pearson correlation coefficient were used to estimate the relationship between the two variables of the study. Results: Aerobic colony count median was 1.71 colony forming units/cm2 (interquartile range = 3.8), whereas adenosine triphosphate median was 59.9 relative light units/cm2 (interquartile range = 128.3). Pearson coefficient R2 was 0.09. Sensitivity and specificity of bioluminescence test with respect to microbiology were 46% and 71%, whereas positive predictive value and negative predictive value were 53% and 65%, respectively. Conclusion: According to our results, there seemed to be no linear correlation between aerobic colony count and adenosine triphosphate values, suggesting that current bioluminescence technology has not any proportional relationships with culturable microbes contaminating environmental surfaces in health-care settings

Evidence-based approach for continuous improvement of occupational health

Introduction. It was recognized early on that an Evidence-Based Medicine (EBM) approach could be applied to Public Health (PH), including the area of Occupational Health (OH). The aim of Evidence-Based Occupational Health (EBOH) is to ensure safety, health, and well-being in the workplace. Currently, high-quality research is necessary in order to provide arguments and scientific evidence upon which effective, efficient, and sustainable preventive measures and policies are to be developed in the workplace in Western countries. Occupational physicians need to integrate available scientific evidence and existing recommendations with a framework of national employment laws and regulations. Objective. This paper addresses the state of the art of scientific evidence available in the field (i.e., efficacy of interventions, usefulness of education and training of workers, and need of a multidisciplinary strategy integrated within the national PH programs) and the main critical issues for their implementation. Conclusions. Promoting good health is a fundamental part of the smart, inclusive growth objectives of Europe 2020 - Europe's growth strategy: keeping people healthy and active for longer has a positive impact on productivity and competitiveness. It appears clear that health quality and safety in the workplace play a key role for smart, sustainable, and inclusive growth in Western countries

WhatsApp Messenger use in oncology: a narrative review on pros and contras of a flexible and practical, non-specific communication tool

The spread of instant messenger systems provides an excellent opportunity and a helpful tool to healthcare professionals. WhatsApp instant messenger use is widely prevalent among health professionals, cancer patients, caregivers and the general population. It is a quick and easy communication tool that may also be used on personal computers and business purposes. WhatsApp instant messenger and other similar tools may be a very useful complement for e-medicine. Instant messaging systems may be helpful, especially in rural areas, in medium- or low-income countries, or to avoid unnecessary travels, improve knowledge and awareness of cancer, monitor home care and support the delivery of home care. The unregulated use of WhatsApp instant messenger requires sound and shared guidelines to assure impeccable professional service. Although a significant number of papers have investigated the roles of social networks in connecting patients to health professionals, there is still a lack of information and scientific data about their uses, benefits and limitations in connecting health providers only for professional communication. The role of instant messenger systems in cancer practice and research needs to be clarified. In this paper, we report a focus on available data, pros and contras of the unregulated use of WhatsApp instant messaging, in the context of e-medicine, as an interprofessional and doctor/patient communication tool in oncology