The self-avoiding walk is a classical model in statistical mechanics, probability theory and mathematical physics. It is also a simple model of polymer entropy which is useful in modelling phase behaviour in polymers. This monograph provides an authoritative examination of interacting self-avoiding walks, presenting aspects of the thermodynamic limit, phase behaviour, scaling and critical exponents for lattice polygons, lattice animals and surfaces. It also includes a comprehensive account of constructive methods in models of adsorbing, collapsing, and pulled walks, animals and (...) networks, and for models of walks in confined geometries. Additional topics include scaling, knotting in lattice polygons, generating function methods for directed models of walks and polygons, and an introduction to the Edwards model.This essential second edition includes recent breakthroughs in the field, as well as maintaining the older but still relevant topics. New chapters include an expanded presentation of directed models, an exploration of methods and results for the hexagonal lattice, and a chapter devoted to the Monte Carlo methods. (shrink)

Several important ethical dilemmas emerge when nurses join a public-sector strike. Such industrial action is commonplace in South Africa and was most notably illustrated by a national wage negotiation in 2010. Media coverage of the proceedings suggested unethical behaviour on the part of nurses, and further exploration is merited. Laws, policies and provisional codes are meant to guide nurses’ behaviour during industrial action, while ethical theories can be used to further illuminate the role of nurses in industrial action. There are, (...) however, important aspects to consider before judging whether nurses act unethically when striking. Following Loewy’s suggestion that the nature of the work, the proceeding commitment of the nurse to the patient, the prevailing situation when the strike is planned and the person(s) who stand(s) to benefit from the strike be considered, coupled with a consideration of the South African historical socio-political context, important aspects of the ethics of nurses’ behaviour in industrial action transpire. (shrink)

Literature on Shared Mental Models has been burgeoning in recent years and this has provided increasingly detailed insight and evidence into the importance of SMMs within specific contexts. However, because past research predominantly focused on SMM structure as measured by diverse, context-dependent measures, a consolidated multi-dimensional measure of perceived SMMs that can be used across diverse team contexts is currently lacking. Furthermore, different conceptualizations of the dimensionality of SMMs exist, which further impedes the comparison between studies. These key limitations might (...) hinder future development in the SMM literature. We argue that the field of SMMs has now matured enough that it is possible to take a deductive approach and evaluate the prior studies in order to refine the key SMMs dimensions, operationalizations, and measurement. Hence, we take a three-stage approach to consolidate existing literature scale-based measures of SMMs, using four samples. Ultimately, this leads to a 20-item five-dimensional scale – the Five Factor Perceived Shared Mental Model Scale. Our scale provides scholars with a tool which enables the measurement, and comparison, of SMMs across diverse team contexts. It offers practitioners the option to more straightforwardly assess perceived SMMs in their teams, allowing the identification of challenges in their teams and facilitating the design of appropriate interventions. (shrink)

In meeting the challenges of fashioning a new health care system, South Africa stands poised to contribute to a better future for its own citizens and the subcontinent.

We propose a new approach for tracing value change. Value change may lead to a mismatch between current value priorities in society and the values for which technologies were designed in the past, such as energy technologies based on fossil fuels, which were developed when sustainability was not considered a very important value. Better anticipating value change is essential to avoid a lack of social acceptance and moral acceptability of technologies. While value change can be studied historically and qualitatively, we (...) propose a more quantitative approach that uses large text corpora. It uses probabilistic topic models, which allow us to trace values that are latent. We demonstrate the approach for five types of value change in technology. Our approach is useful for testing hypotheses about value change, such as verifying whether value change has occurred and identifying patterns of value change. The approach can be used to trace value change for various technologies and text corpora, including scientific articles, newspaper articles, and policy documents. (shrink)

The practice of coercive measures in psychiatry is controversial. Although some have suggested that it may be acceptable if patients are a danger to others or to themselves, others committed themselves to eliminate it. Ethical, legal and clinical considerations become more complex when the mental incapacity is temporary and when the coercive measures serve to restore autonomy. We discuss these issues, addressing the conflict between autonomy and beneficence/non-maleficence, human dignity, the experiences of patients and the effects of coercive measures. We (...) argue that an appeal to respect autonomy and/or human dignity cannot be a sufficient reason to reject coercive measures. All together, these ethical aspects can be used both to support and to reject a non-seclusion approach. The total lack of controlled trials about the beneficial effects of coercive measures in different populations however, argues against the use of coercive measures. (shrink)

This article addresses the ability of Parallel Distributed Processing (PDP) networks to generate stagewise cognitive development in accordance with Piaget's theory of cognitive epigenesis. We carried out a replication study of the simulation experiments by McClelland (1989) and McClelland and Jenkins (1991) in which a PDP network learns to solve balance scale problems. In objective tests motivated from catastrophe theory, a mathematical theory of transitions in epigenetical systems, no evidence for stage transitions in network performance was found. It is concluded (...) that PDP networks lack the ability to recover the positive outcomes of analogous catastrophe analyses of real cognitive developmental data. In an attempt to further characterize the learning behaviour of PDP networks, we carried out a second simulation study using the discrimination‐shift paradigm. The results thus obtained indicate that PDP learning is compatible with the learning of stimulus‐response relationships, not with the acquisition of mediating rules such as conceived in (neo‐)Piagetian theory. In closing, we speculate about the feasibility of simulating stagewise development with alternative network architectures. (shrink)

Cross-education is the phenomenon in which repeated practice of a unilateral motor task does not only result in performance improvement of the trained limb, but also in the untrained contralateral limb. The aim of this study was to test whether cross-education or positive transfer of learning is also achieved for tasks in which both limbs contribute in different ways by using modified equipment that switches the limbs’ role. To this end, a reverse field hockey stick was used that requires a (...) mirroring of arm and hand use and dominance. Two groups of young skilled female field hockey players participated in a crossover-design, in which participants received four training sessions with a reverse hockey stick followed by four training sessions with a regular hockey stick, or vice versa. In a pre-test, intermediate test, a post-test and a retention test, participants’ performance on a field hockey skill test with a regular hockey stick was measured. The results revealed that training with the reversed hockey stick led to significantly increased improvements compared to training with a regular hockey stick. We conclude that modified equipment can be used to exploit positive transfer of learning by switching the limbs’ roles. The findings are discussed by referring to the symmetry preservation principle in dynamic systems theory and have clear practical relevance for field hockey trainers and players seeking to further improve field hockey skills. (shrink)

Approximately one in three adults has reported being abused or neglected by a caregiver during their childhood (i.e., they have experienced child maltreatment), though the exact prevalence differs...