Opinion dynamics of learning agents: does seeking consensus lead to disagreement?

We study opinion dynamics in a population of interacting adaptive agents voting on a set of issues represented by vectors. We consider agents who can classify issues into one of two categories and can arrive at their opinions using an adaptive algorithm. Adaptation comes from learning and the information for the learning process comes from interacting with other neighboring agents and trying to change the internal state in order to concur with their opinions. The change in the internal state is driven by the information contained in the issue and in the opinion of the other agent. We present results in a simple yet rich context where each agent uses a Boolean perceptron to state their opinion. If the update occurs with information asynchronously exchanged among pairs of agents, then the typical case, if the number of issues is kept small, is the evolution into a society torn by the emergence of factions with extreme opposite beliefs. This occurs even when seeking consensus with agents with opposite opinions. If the number of issues is large, the dynamics becomes trapped, the society does not evolve into factions and a distribution of moderate opinions is observed. The synchronous case is technically simpler and is studied by formulating the problem in terms of differential equations that describe the evolution of order parameters that measure the consensus between pairs of agents. We show that for a large number of issues and unidirectional information flow, global consensus is a fixed point; however, the approach to this consensus is glassy for large societies.

Opinion of hepatic transplant waiting list patients regarding split liver transplantation

Background. Split liver transplantation (SLT) increases organ supply for hepatic transplantation. Long-term patient survival and complication rates seem to be equivalent between orthotopic liver transplantation (OLT) and SLT. There are controversies among transplant physicians due to an ethical dilemma between benefiting individual needs or those of society. Barshes and Goss (Am J Transplant 5:2047, 2005) demonstrated that the majority of adult liver transplant candidates are favorable to SLT. The aim of our study was to evaluate the opinions of patients at a Brazilian university hospital regarding SLT.Materials and Methods. A questionnaire with 14 questions was applied to 50 patients included in a hepatic transplant waiting list regarding SLT.Results. The overall attitudes of 66% of the participants were classified as utilitarian, 31% were classified as self-preserving, and 3% were undecided. Ninety-one percent of patients would be willing to share even if their expected survival after SLT was shorter than that with OLT. For 77% of patients, children must have priority over adults. However, 83% were unaware of the donors for pediatric transplantations.Conclusions. SLT is a consistent solution for organ demand despite controversies among transplant physicians. The present study demonstrated that most patients were favorable to SLT. In conclusion, attitudes toward graft sharing are not barriers to SLT.

Expert opinion as an instrument for assessing investment in primary education

Includes bibliography

Spirituality: Do teachers and students hold the same opinion?

Background:  Few studies have investigated potential differences between the opinions of educators and undergraduates regarding spirituality in patient care. Understanding these differences, could lead to better strategies for educational proposes. Purpose:  To compare the opinions of medical teachers (MTs) and medical students (MSs) regarding spirituality training in a Brazilian medical school. Methods:  A cross-sectional study was conducted. MTs and MSs filled out a questionnaire containing the Duke Religion Index, and questions regarding spirituality in clinical practice and at medical school. A comparison between early-curriculum MSs, late curriculum MSs and MTs was carried out. Chi-square (categorical) and Mann-Whitney (continuous/ordinal) tests were used. Results:  A total of 475 MSs and 44 MTs were evaluated. Results showed that MSs did not address spirituality as frequently as MTs (p<0.001), and that most participants did not feel prepared to address this issue, and believe that Brazilian medical schools are not giving all the required information in this field. Nevertheless, they believe MSs should be prepared to discuss these issues. Late-curriculum MSs believed that spirituality plays a more positive role in patient health (p=0.027), and were more prone to address this issue than early-curriculum MSs (p=0.023). Conclusion:  These findings revealed some of the challenges faced by spirituality medical training in Brazil, and differences between MTs and MSs regarding this issue. Further studies are needed to replicate these findings in other countries. © Blackwell Publishing Ltd 2013.

Seeking a Second Opinion: Uncertainty in Disease Ecology

Analytical methods accounting for imperfect detection are often used to facilitate reliable inference in population and community ecology. We contend that similar approaches are needed in disease ecology because these complicated systems are inherently difficult to observe without error. For example, wildlife disease studies often designate individuals, populations, or spatial units to states (e.g., susceptible, infected, post-infected), but the uncertainty associated with these state assignments remains largely ignored or unaccounted for. We demonstrate how recent developments incorporating observation error through repeated sampling extend quite naturally to hierarchical spatial models of disease effects, prevalence, and dynamics in natural systems. A highly pathogenic strain of avian influenza virus in migratory waterfowl and a pathogenic fungus recently implicated in the global loss of amphibian biodiversity are used as motivating examples. Both show that relatively simple modifications to study designs can greatly improve our understanding of complex spatio-temporal disease dynamics by rigorously accounting for uncertainty at each level of the hierarchy.

Water transfer from São Francisco river to semiarid northeast of Brazil: technical data, environmental impacts, survey of opinion about the amount to be transferred

The transposition of the São Francisco River is considered one of the greatest engineering works in Brazil of all time since it will cross an extensive agricultural region of continental dimensions, involving environmental impacts, water, soil, irrigation, water payment and other multidisciplinary themes. Taking into account its importance, this subject was incorporated into a discipline of UFSCar (Federal University of São Carlos - Brazil) named "Pollution and Environmental Impacts". It was noted strong reaction against the project, even before the presentation. To allow a critical analysis, the first objective was to compile the main technical data and environmental impacts. The second objective was to detect the three most important aspects that cause reaction, concluding for the following reasons: assumption that the volume of water to be transferred was much greater than it actually is proposed in the project; lack of knowledge about similar project already done in Brazil; the idea that the artificial canal to be built was much broader than that proposed by the project. The participants' opinion about "volume to be transferred" was raised quantitatively four times: 2-undergraduate students; 1-graduate; 1-outside community. The average resulted 14 times larger than that proposed in the project, significant according to t-test. It was concluded that the reaction to water transfer project is due in part to the ignorance combined with a preconceived idea that tend to overestimate the magnitude of environmental impacts.

Psychosocial stress and cardiovascular risk : current opinion

Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. Epidemiologic research of the last half-century has clearly shown that psychosocial factors related to the social environment, personality characteristics, and negative affect increase the risk of incident CVD and also impact prognosis of cardiac patients. Several mechanisms may explain this link, including a genetic predisposition, poor lifestyle choices, low adherence to health recommendations, and direct pathophysiologic perturbations. The latter include alteration of the hypothalamic-pituitary adrenal axis and autonomic dysfunction resulting in endothelial dysfunction, inflammation, and a prothrombotic state further downstream. Screening for psychosocial factors seems appropriate as part of the standard history and based on the clinician's knowledge of the patient and the purpose of the visit. Psychological interventions generally alleviate distress in cardiac patients, but whether they reduce the risk of hard cardiovascular endpoints and all-cause mortality is less evident. Cardiac patients with more severe depression may particularly profit from antidepressant medications. Due to their pharmacologic properties, selective serotonin reuptake inhibitors were shown to improve cardiovascular outcome. The most effective psychosocial treatment is multicomponent therapy that combines elements of cognitive behaviour therapy ("stress management") and changes in health behaviours, including the adoption of a regular exercise regimen. Gender-specific issues should probably be considered. The field of behavioural cardiology has accumulated a wealth of epidemiological, mechanistic and clinical knowledge that undoubtedly has furthered our understanding about the important role of psychosocial risk factors in patients with a heart disease.

Strabismus and employment: the opinion of headhunters

Abstract. Purpose: The aim of this study was to determine the influence of strabismus on an individual's ability to find employment based on the opinion of Swiss headhunters. Methods: Forty Swiss headhunters retrieved from a Swiss online telephone directory were interviewed using a validated questionnaire in order to determine if strabismus would have an impact on a person's ability to find employment. Photographs of a strabismic man and woman as well as of other computer-generated facial anomalies could be downloaded from the Internet during the interview. Results: 72.5% of headhunters judged that strabismic individuals would have more difficulties in finding a job than orthotropic persons. These difficulties were judged to be stronger in women than in men (P = 0.006), and in exotropic compared to esotropic persons (P = 0.01). Asked about seven facial anomalies, exotropia was found to have the third and esotropia the fourth (women) or fifth (men) most strongly negative impact on finding employment, after having strong acne and a visible missing tooth. Headhunters judged that persons with strabismus are significantly perceived as less attractive and less intelligent by potential employers. Conclusion: Visible strabismus negatively influences individuals' ability to find a job and therefore has an impact on their economic status. Successful strabismus surgery realigns the visual axes, producing a normal facial appearance and therefore eliminating the negative impact of strabismus on employability.

Opinion of headhunters about the ability of strabismic subjects to obtain employment

BACKGROUND: Through the opinion of Swiss headhunters, we wanted to determine the influence of strabismus on the ability to obtain employment. METHODS: Out of 31 randomly selected Swiss headhunters, 20 could be interviewed using a validated questionnaire. RESULTS: Forty-seven percent of the headhunters judged that strabismic subjects have more difficulties in obtaining a job. Gender has no influence on discrimination (p > 0.1). Asked about six facial disfigurements, strabismus was found to have the second largest negative impact on employment directly after acne. Strabismus was estimated to decrease the attractiveness of job applicants (p < 0.0001) and to have a negative impact on the overall judgment of a potential employer (p < 0.05). CONCLUSIONS: Visible strabismus influences negatively the ability to obtain a job. Because of its impact on the employability of a person, we believe that strabismus surgery in adults cannot be considered to be only a beautifying procedure.

Political Depolarization in German Public Opinion, 1980–2010

Little is known about political polarization in German public opinion. This article offers an issue-based perspective and explores trends of opinion polarization in Germany. Public opinion polarization is conceptualized and measured as alignment of attitudes. Data from the German General Social Survey (1980 to 2010) comprise attitudes towards manifold issues, which are classified into several dimensions. This study estimates multilevel models that reveal general and issue- as well as dimension-specific levels and trends in attitude alignment for both the whole German population and sub-groups. It finds that public opinion polarization has decreased over the last three decades in Germany. In particular, highly educated and more politically interested people have become less polarized over time. However, polarization seems to have increased in attitudes regarding gender issues. These findings provide interesting contrasts to existing research on the American public.

Expert opinion on toxicity profiling--report from a NORMAN expert group meeting.

This article describes the outcome and follow-up discussions of an expert group meeting (Amsterdam, October 9, 2009) on the applicability of toxicity profiling for diagnostic environmental risk assessment. A toxicity profile was defined as a toxicological "fingerprint" of a sample, ranging from a pure compound to a complex mixture, obtained by testing the sample or its extract for its activity toward a battery of biological endpoints. The expert group concluded that toxicity profiling is an effective first tier tool for screening the integrated hazard of complex environmental mixtures with known and unknown toxicologically active constituents. In addition, toxicity profiles can be used for prioritization of sampling locations, for identification of hot spots, and--in combination with effect-directed analysis (EDA) or toxicity identification and evaluation (TIE) approaches--for establishing cause-effect relationships by identifying emerging pollutants responsible for the observed toxic potency. Small volume in vitro bioassays are especially applicable for these purposes, as they are relatively cheap and fast with costs comparable to chemical analyses, and the results are toxicologically more relevant and more suitable for realistic risk assessment. For regulatory acceptance in the European Union, toxicity profiling terminology should keep as close as possible to the European Water Framework Directive (WFD) terminology, and validation, standardization, statistical analyses, and other quality aspects of toxicity profiling should be further elaborated.