Emergent explosive synchronization in adaptive complex networks.

Adaptation plays a fundamental role in shaping the structure of a complex network and improving its functional fitting. Even when increasing the level of synchronization in a biological system is considered as the main driving force for adaptation, there is evidence of negative effects induced by excessive synchronization. This indicates that coherence alone cannot be enough to explain all the structural features observed in many real-world networks. In this work, we propose an adaptive network model where the dynamical evolution of the node states toward synchronization is coupled with an evolution of the link weights based on an anti-Hebbian adaptive rule, which accounts for the presence of inhibitory effects in the system. We found that the emergent networks spontaneously develop the structural conditions to sustain explosive synchronization. Our results can enlighten the shaping mechanisms at the heart of the structural and dynamical organization of some relevant biological systems, namely, brain networks, for which the emergence of explosive synchronization has been observed.

Cardiovascular Diseases Risk Factors in oil and gas workers: a ten years observational retrospective cohort.

OBJECTIVES: The study aim was to examine the trend of major clinical biochemistry factors associated with cardiovascular diseases and dyslipidemia onset over a 10-year period (2000-2010) in Oil and Gas workers. METHODS: The information extracted from "Computerized management of individual medical services database" regarding 439 Italian workers of an oil and gas company were analysed. RESULTS: A constant and significant increase of the average Body Mass Index and serum cholesterol were found, and in particular in workers < 36 years: BMI was 24.4 (2000) and 25.8 (2010) with p < 0.001, and cholesterol was 188.3 mg/dL (2000) and 206.5 mg/dL (2010) with p < 0.001. CONCLUSION: Analysed variables are the most important risk factor for cardiovascular, neurological and neoplastic diseases, as well as they reduce life expectancy. Occupational medicine in particular in extreme working environmental conditions, such as for workers in oil and gas companies, monitoring health status and promoting healthy life style, has a strategic role to perform cost-effective strategies to reduce health risks, thus improving the workers lifestyle.

Hybrid recommendation methods in complex networks.

We propose two recommendation methods, based on the appropriate normalization of already existing similarity measures, and on the convex combination of the recommendation scores derived from similarity between users and between objects. We validate the proposed measures on three data sets, and we compare the performance of our methods to other recommendation systems recently proposed in the literature. We show that the proposed similarity measures allow us to attain an improvement of performances of up to 20% with respect to existing nonparametric methods, and that the accuracy of a recommendation can vary widely from one specific bipartite network to another, which suggests that a careful choice of the most suitable method is highly relevant for an effective recommendation on a given system. Finally, we study how an increasing presence of random links in the network affects the recommendation scores, finding that one of the two recommendation algorithms introduced here can systematically outperform the others in noisy data sets.

Nonlinear growth and condensation in multiplex networks.

Different types of interactions coexist and coevolve to shape the structure and function of a multiplex network. We propose here a general class of growth models in which the various layers of a multiplex network coevolve through a set of nonlinear preferential attachment rules. We show, both numerically and analytically, that by tuning the level of nonlinearity these models allow us to reproduce either homogeneous or heterogeneous degree distributions, together with positive or negative degree correlations across layers. In particular, we derive the condition for the appearance of a condensed state in which one node in each layer attracts an extensive fraction of all the edges.

Growing multiplex networks.

We propose a modeling framework for growing multiplexes where a node can belong to different networks. We define new measures for multiplexes and we identify a number of relevant ingredients for modeling their evolution such as the coupling between the different layers and the distribution of node arrival times. The topology of the multiplex changes significantly in the different cases under consideration, with effects of the arrival time of nodes on the degree distribution, average shortest path length, and interdependence.

Assessment of acceptability and ease of use of atovaquone/proguanil medication in subjects undergoing malaria prophylaxis.

OBJECTIVE: International travelers from non-endemic areas are at high risk of contracting malaria due to their lack of immunity. Prevention is therefore of outmost importance and is achieved through effective and safe chemoprophylaxis, which reduces the risk of fatal disease. Among the various antimalarial drugs available, the synergistic combination of atovaquone and proguanil (A/P) (Malarone((R)); Glaxo-SmithKline) has proven a valuable option in terms of effective protection against chloroquine and multi-drug resistant falciparum malaria, safety, tolerability, and ease of use, thus favoring compliance. The purpose of the present study was to assess acceptability and ease of use of A/P chemoprophylaxis in a population of employees of the oil industry bound to malarious areas. Particular attention was paid to treatment adherence. METHODS: A survey was conducted on a sample of 700 employees on A/P chemoprophylaxis. Demographic data and specific information on A/P treatment were collected by means of a 16-item questionnaire administered immediately before departure. All questionnaires returned were then entered into a database and statistically analyzed. RESULTS: Both habitual and first-time travelers showed good adherence to A/P chemoprophylactic regimen. In general, only few adverse side-effects were reported, none of which were serious. Travelers with previous experience of other antimalarials stated A/P prophylaxis had proven advantageous due to fewer adverse reactions, better condition of administration, and better sense of protection compared with other available treatments.

[Health management of Saipem workers with projects involving abroad activities]. / Gestione della salute dei dipendenti Saipem S.p.A. assegnati ai progetti lavorativi all'estero.

In remote areas and in developing countries, where adequate health-care structures are few and sparse, Occupational Medicine contributes to guaranteeing workers' health. Companies like Saipem, involved in activities that are carried out in remote, inhospitable areas must ensure the safety and guarantee the health conditions of workers in relation to the risk factors connected with the job as well as with the environment in which it is performed. In such situations, Occupational Medicine addresses both the health aspects of the workplace and of the community, and is the pivot around which revolves the health-care support of workers employed abroad in the sense of protection and enhancement of health. The risks connected with work abroad are of three main types: 1) job-related risks; 2) risks connected with the environment; 3) risks related to the organization of work and the changes in the worker's daily life. The job-related risks are similar to those connected with analogous jobs performed elsewhere. The risks connected with the environment are related to adverse climatic conditions, extreme temperatures and unknown and often dangerous flora and fauna. The occupational physician is called upon to assess the suitability of workers for jobs that are based in remote areas. The main clinical conditions that can prevent issue of the Medical Fitness Certificate to workers for long-stay jobs abroad are discussed.

Evaluation of MAO activities on murine neuroblastoma cells upon acute or chronic treatment with aluminium (III) or tacrine.

Monoamine-oxidase catalyses the oxidative deamination of various primary amines such as norepinephrine, serotonin, dopamine and others. Such an enzyme exists under two well known isotypes, A and B. In the brain monoamine-oxidase activity increases with ageing. The present paper reports data regarding the evaluation on the activity of monoamine-oxidase A and B in murine neuroblastoma cells carried out by a radioassay upon acute or chronic treatment of cells by aluminium or tacrine. Our data show that aluminium has a pronounced activatory effect on both enzymatic isoforms either in acute or long-term adaptation treatment. Conversely, tacrine produces an inhibitory effect of both monoamine oxidase isotypes after an acute treatment, while an inhibitory effect on the isoform A and an activation of the isoform B in long-term adaptation was observed. Such effects are discussed in terms of aluminium neurotoxicity and therapeutic implications for tacrine.

Prevalence of pertussis IgG antibodies in children in Palermo, Italy.

The prevalence of IgG antibodies to Bordetella pertussis in a sample of 615 1-12-year-old unvaccinated children in Palermo was estimated by ELISA. The overall prevalence was 56%; it increased from 24% in one to three-year-old children to 67% in 11-12-year-old children (p less than 0.01). IgG antibody prevalence was not associated with the father's years of schooling (OR 1), nor with the family size (OR 1.3; C.I. 95% = 0.8-2.2). For children aged one the three years, serological results showed that the history of pertussis reported by parents in questionnaires gave high specificity (93.2%) and negative predictive value (85.4%). Our seroepidemiological study evidences a great exposure of children to B. pertussis in Palermo, with a high proportion of infections occurring after three years of age.