Using Role Play to Debate Animal Testing

The use of animals in biomedical research is a socio-scientific issue in which decision-making is complicated. In this article, we describe an experience involving a role play activity performed during school visits to the Barcelona Biomedical Research Park (PRBB) to debate animal testing. Role playing games require students to defend different positions and permit participants to debate and reflect on their personal opinions. A total of 262 students from 15- to 30-years-old participated in the activity. The article presents an analysis of the students’ opinions on this topic before and after performing the activity. Our results show that students actively took part in debate and made use of the new information provided by the game, especially the legal aspects. In conclusion, the role play activity helped participants to create a more informed opinion, stimulated critical thinking and argumentation skills. We encourage science teachers to use role playing games to discuss socio-scientific issues.     

Toward a Science of Welfare for Animals in the Zoo

Although the accredited institutions of the Association of Zoos and Aquariums have all committed to enhancing the welfare of nonhuman animals, acceptable standards and best practices are still under debate. Currently, experts from zoos and the field hold widely divergent opinions about exhibition and management standards for elephants. Standards and practices for managing nonhuman primates provide a model for other nonhuman creatures exhibited in zoos and aquariums. Examining the key issues for primates demonstrates the value of applying scientific data before promulgating standards. The field of applied behavior analysis provides a wealth of information to frame the debate. Animal behaviorists have contributed to an emerging science of animal welfare, which may provide a foundation for empirical zoo management, standards, and practices.     

Toward a science of welfare for animals in the zoo

Although the accredited institutions of the Association of Zoos and Aquariums have all committed to enhancing the welfare of nonhuman animals, acceptable standards and best practices are still under debate. Currently, experts from zoos and the field hold widely divergent opinions about exhibition and management standards for elephants. Standards and practices for managing nonhuman primates provide a model for other nonhuman creatures exhibited in zoos and aquariums. Examining the key issues for primates demonstrates the value of applying scientific data before promulgating standards. The field of applied behavior analysis provides a wealth of information to frame the debate. Animal behaviorists have contributed to an emerging science of animal welfare, which may provide a foundation for empirical zoo management, standards, and practices.     

The Undecided Have the Key: Interaction-Driven Opinion Dynamics in a Three State Model

The effects of interpersonal interactions on individual’s agreements result in a social aggregation process which is reflected in the formation of collective states, as for instance, groups of individuals with a similar opinion about a given issue. This field, which has been a longstanding concern of sociologists and psychologists, has been extended into an area of experimental social psychology, and even has attracted the attention of physicists and mathematicians. In this article, we present a novel model of opinion formation in which agents may either have a strict preference for a choice, or be undecided. The opinion shift emerges, in a threshold process, as a consequence of a cumulative persuasion for either one of the two opinions in repeated interactions. There are two main ingredients which play key roles in determining the steady states: the initial fraction of undecided agents and the change in agents’ persuasion after each interaction. As a function of these two parameters, the model presents a wide range of solutions, among which there are consensus of each opinion and bi-polarization. We found that a minimum fraction of undecided agents is not crucial for reaching consensus only, but also to determine a dominant opinion in a polarized situation. In order to gain a deeper comprehension of the dynamics, we also present the theoretical framework of the model. The master equations are of special interest for their nontrivial properties and difficulties in being solved analytically.     

The place of genetics in ageing research

Rapidly increasing numbers of older people present many countries with growing social and economic challenges. Yet despite the far-reaching implications of ageing, its biological basis remains a topic of much debate. Recent advances in genomics have spurred research on ageing and lifespan in human populations, adding to extensive genetic studies being carried out in model organisms. But how far is ageing controlled by our genes? In this Viewpoint, six experts present their opinions and comment on future directions in ageing research.     

What research with stored samples teaches us about research with human subjects

There is widespread discussion concerning the safeguards appropriate for human research subjects. Less discussed is the fact that the safeguards one deems appropriate depend, in large part, on the model of research participation that one assumes. Therefore, to determine what safeguards are appropriate, it is necessary first to clarify the competing models of research participation. The ostensibly obscure debate over informed consent for research on stored biological samples is of particular interest in this regard because such research can involve varying subsets of the three central elements of research involvement. As a result, analysis of this debate provides an opportunity to identify the competing models of research participation. Based on this analysis, this paper describes a new model of research participation that is emerging, and considers its implications for clinical research.     

Instability and excitation propagation in a catalytic reaction model. II. Distributed system model]

The regime of excitation propagation in monomeric model of active medium is considered. Conditions exist when the phase plane falls into two regions in both of which the equations are linear and their automodel solutions are found analytically. After connecting the solutions a transcendental algebraic equation is obtained, from which the values of excitation propagation rate can be found. The trigger wave has one rate value the propagating impulse--two (physically realised--one). There is a parameter region with four rates (three physically realised ones).     

On euthanasia: exploring psychological meaning and attitudes in a sample of Mexican physicians and medical students

Euthanasia has become the subject of ethical and political debate in many countries including Mexico. Since many physicians are deeply concerned about euthanasia, due to their crucial participation in its decision and implementation, it is important to know the psychological meaning that the term 'euthanasia' has for them, as well as their attitudes toward this practice. This study explores psychological meaning and attitudes toward euthanasia in 546 Mexican subjects, either medical students or physicians, who were divided into three groups: a) beginning students, b) advanced students, and c) physicians. We used the semantic networks technique, which analyzed the words the participants associated with the term 'euthanasia'. Positive psychological meaning, as well as positive attitudes, prevailed among advanced students and physicians when defining euthanasia, whereas both positive and negative psychological meaning together with more ambivalent attitudes toward euthanasia predominated in beginning students. The findings are discussed in the context of a current debate on a bill proposing active euthanasia in Mexico City.     

Opinions of Turkish physicians towards termination of pregnancy for fetal disorders

Termination of pregnancy (ToP) raises ethical dilemmas. Although ToP for fetal disorders is commonly approved by health professionals, their opinions and attitudes are influenced by a diversity of cultural contexts. The aim of the study is to investigate Turkish physicians' opinions on ToP for fetal disease and the hypothesis is that their opinions are influenced by whether they face any disabilities of affected children or not. We aimed to survey by a questionnaire the opinions of Turkish physicians towards ToP for untreatable fetal disorders. A group of 250 subjects was included in the study. Physicians' approval of parents' decision for ToP was higher for disorders that they encounter more frequently during their daily work. Their opinions were not statistically different when compared for gender and marital status, however, having children of their own caused significant differences for some of the disorders. Approximately 65% of the participants responded that families alone should have the right to decide on ToP. The results confirm that health professionals may have differences in perception of severity of diseases, based on their clinical experience. Physicians encountering affected children more likely approve ToP for that particular disease.     

Estimation and inference for a spline-enhanced population pharmacokinetic model

This article is motivated by an application where subjects were dosed three times with the same drug and the drug concentration profiles appeared to be the lowest after the third dose. One possible explanation is that the pharmacokinetic (PK) parameters vary over time. Therefore, we consider population PK models with time-varying PK parameters. These time-varying PK parameters are modeled by natural cubic spline functions in the ordinary differential equations. Mean parameters, variance components, and smoothing parameters are jointly estimated by maximizing the double penalized log likelihood. Mean functions and their derivatives are obtained by the numerical solution of ordinary differential equations. The interpretation of PK parameters in the model and its flexibility are discussed. The proposed methods are illustrated by application to the data that motivated this article. The model's performance is evaluated through simulation.     

Stochastic models of kleptoparasitism

In this paper, we consider a model of kleptoparasitism amongst a small group of individuals, where the state of the population is described by the distribution of its individuals over three specific types of behaviour (handling, searching for or fighting over, food). The model used is based upon earlier work which considered an equivalent deterministic model relating to large, effectively infinite, populations. We find explicit equations for the probability of the population being in each state. For any reasonably sized population, the number of possible states, and hence the number of equations, is large. These equations are used to find a set of equations for the means, variances, covariances and higher moments for the number of individuals performing each type of behaviour. Given the fixed population size, there are five moments of order one or two (two means, two variances and a covariance). A normal approximation is used to find a set of equations for these five principal moments. The results of our model are then analysed numerically, with the exact solutions, the normal approximation and the deterministic infinite population model compared. It is found that the original deterministic models approximate the stochastic model well in most situations, but that the normal approximations are better, proving to be good approximations to the exact distribution, which can greatly reduce computing time.     

Quality-of-life measurements: origin and pathogenesis

Despite extensive growth in recent years, the field of "quality-of-life" appraisal still evokes debate about basic perception of the concept and is accompanied by a plethora of indexes for measurement. One prime reason for the problems is that the measurements have been transferred from two separate sources - medical health status indexes and social-science population indexes - neither of which was designed for appraising the particular personal distinctions of the way people feel about their own quality of life. When regulatory and commercial incentives were offered for measuring patients' quality of life, it became appraised with the indexes available from the medical and psychosocial sources, even though neither set of indexes was specifically intended for that purpose. They are not developed from the basic principle that a person's "quality of life" is a state of mind, not a state of health, which is uniquely perceived by that person, and which will not be appropriately appraised unless the most cogent personal components are allowed suitable expressions. An approach that lets patients state their own opinions directly can offer the "face validity" or "common sense" that now seems absent from the generally applied measurements.     

Analysis of the response properties of a computationally efficient spike initiator model

 A simple model for neuronal spike initiation is presented. It comprises two linear differential equations and is based on the work of Hill, Rashevsky and Monnier (Rashevsky 1933; Monnier 1934; Hill 1936). Three different versions of the model and the corresponding assumptions are described. The intrinsic noise model used with the deterministic equations is described. The equations are analyzed through the direct solution of relevant equations and the technique of phase plane analysis. The analysis reveals that a subset of the model parameters is responsible for the distinction between spike initiator models which fire a single spike and those that fire repetitively in the presence of a sustained stimulus. Relationships between stimulus intensity and different modes of operation are derived. The effects of the three different versions of the model are compared analytically. Received: 5 August 1993/Accepted in revised form: 24 February 1994     

Hypercycles versus parasites in the origin of life: model dependence in spatial hypercycle systems

Spatial hypercycle systems can be modelled by means of cellular automata or partial differential equations. In either model, two dimensional spirals or clusters can be formed. Different models give rise to slightly different spatial structures, but the response to parasites is fundamentally different: In cellular automata the hypercycle is resistant to parasites that are fatal in a partial differential equations model. In three dimensions scroll rings correspond to the two dimensional spirals. Numerical simulations on a partial differential equations model indicate that the scroll rings are unstable: The contract by a power law and disappear. Therefore, in three dimensions clusters seem to be the best candidate for the hypercycle resistant to parasites.     

The Origin of Homo sapiens in the Light of Different Research Methods

The origins of Homo sapiens is a central issue of modern paleoanthropology. The available fossil material serves as a basis for postulating different hypotheses and models, but as is widely appreciated, anthropologists have yet to reach a consensus about human origins. It seems possible that the main reasons behind such an irreducible divergence of opinions are different methodological approaches rather than the analyses of fossil material. Some scientists would say that it is the fragmentary nature of fossil material which accounts for the debates about the origins of H. sapiens. Had the debate been only a matter of the empirical considerations many disagreements concerning H. sapiens would have probably disappeared long ago. But since the controversies are imbued in methodological reality the closure of the debate is not to be expected soon. There are three research methods: morphological, archaeological and genetic. Each approach has a specific definition of H. sapiens at its disposal, which largely accounts for the different scenarios for the origin of our species. Any debate concerning this problem must therefore begin with a discussion about the research methods. The controversy about our origins thus appears to be of secondary importance. The present paper aims at presenting the methodological controversy in relation to the origins of H. sapiens. The discussion about the genealogy of H. sapiens certainly is in urgent need of a new, more integrated way of approaching the past.     

Social Influence and the Collective Dynamics of Opinion Formation

Social influence is the process by which individuals adapt their opinion, revise their beliefs, or change their behavior as a result of social interactions with other people. In our strongly interconnected society, social influence plays a prominent role in many self-organized phenomena such as herding in cultural markets, the spread of ideas and innovations, and the amplification of fears during epidemics. Yet, the mechanisms of opinion formation remain poorly understood, and existing physics-based models lack systematic empirical validation. Here, we report two controlled experiments showing how participants answering factual questions revise their initial judgments after being exposed to the opinion and confidence level of others. Based on the observation of 59 experimental subjects exposed to peer-opinion for 15 different items, we draw an influence map that describes the strength of peer influence during interactions. A simple process model derived from our observations demonstrates how opinions in a group of interacting people can converge or split over repeated interactions. In particular, we identify two major attractors of opinion: (i) the expert effect, induced by the presence of a highly confident individual in the group, and (ii) the majority effect, caused by the presence of a critical mass of laypeople sharing similar opinions. Additional simulations reveal the existence of a tipping point at which one attractor will dominate over the other, driving collective opinion in a given direction. These findings have implications for understanding the mechanisms of public opinion formation and managing conflicting situations in which self-confident and better informed minorities challenge the views of a large uninformed majority.     

Sample Size Considerations for GEE Analyses of Three‐Level Cluster Randomized Trials

Summary Cluster randomized trials in health care may involve three instead of two levels, for instance, in trials where different interventions to improve quality of care are compared. In such trials, the intervention is implemented in health care units (“clusters”) and aims at changing the behavior of health care professionals working in this unit (“subjects”), while the effects are measured at the patient level (“evaluations”). Within the generalized estimating equations approach, we derive a sample size formula that accounts for two levels of clustering: that of subjects within clusters and that of evaluations within subjects. The formula reveals that sample size is inflated, relative to a design with completely independent evaluations, by a multiplicative term that can be expressed as a product of two variance inflation factors, one that quantifies the impact of within‐subject correlation of evaluations on the variance of subject‐level means and the other that quantifies the impact of the correlation between subject‐level means on the variance of the cluster means. Power levels as predicted by the sample size formula agreed well with the simulated power for more than 10 clusters in total, when data were analyzed using bias‐corrected estimating equations for the correlation parameters in combination with the model‐based covariance estimator or the sandwich estimator with a finite sample correction.     

Spatial reconstruction of the human motion based on images of a single camera

The inverse dynamic analysis procedures used in the study of the human gait require that the kinematics of the supporting biomechanical model is known beforehand. The first step to obtain the kinematic data is the reconstruction of human spatial motion, i.e., the evaluation of the anatomic points positions that enables to uniquely define the position of all anatomical segments. In photogrammetry, the projection of each anatomical point is described by two linear equations relating its three spatial coordinates with the two coordinates of the projected point. The need for the image of two cameras arises from the fact that three equations are necessary to find the original spatial position of the anatomical point. It is shown here that the kinematic constraint equations associated with a biomechanical model can be used as the extra set of equations required for the reconstruction process, instead of the equations associated with the second camera. With this methodology, the system of equations arising from the point projections and biomechanical model kinematic constraints are solved simultaneously. Since the system of equations has multiple solutions for each image, a strategy based on the minimization of the cost function associated to the smoothness of the reconstructed motion is devised, leading to an automated computer procedure enabling a unique reconstruction.     

Protein Distributions from a Stochastic Model of the lac Operon of E. coli with DNA Looping: Analytical solution and comparison with experiments

Although noisy gene expression is widely accepted, its mechanisms are subjects of debate, stimulated largely by single-molecule experiments. This work is concerned with one such study, in which Choi et al., 2008, obtained real-time data and distributions of Lac permease in E. coli. They observed small and large protein bursts in strains with and without auxiliary operators. They also estimated the size and frequency of these bursts, but these were based on a stochastic model of a constitutive promoter. Here, we formulate and solve a stochastic model accounting for the existence of auxiliary operators and DNA loops. We find that DNA loop formation is so fast that small bursts are averaged out, making it impossible to extract their size and frequency from the data. In contrast, we can extract not only the size and frequency of the large bursts, but also the fraction of proteins derived from them. Finally, the proteins follow not the negative binomial distribution, but a mixture of two distributions, which reflect the existence of proteins derived from small and large bursts.