A randomized trial of a problem-based learning approach for teaching epidemiology

Purpose. To conduct a controlled trial of traditional and problem-based learning (PBL) methods of teaching epidemiology. Method. All second-year medical students (n = 136) at The University of Western Australia Medical School were offered the chance to participate in a randomized controlled trial of teaching methods fur an epidemiology course. Students who consented to participate (n = 80) were randomly assigned to either a PBL or a traditional course. Students who did not consent or did not return the consent form (n = 56) were assigned to the traditional course, Students in both streams took identical quizzes and exams. These scores, a collection of semi-quantitative feedback from all students, and a qualitative analysis of interviews with a convenience sample of six students from each stream were compared. Results. There was no significant difference in performances on quizzes or exams between PBL and traditional students. Students using PBL reported a stronger grasp of epidemiologic principles, enjoyed working with a group, and, at the end of the course, were more enthusiastic about epidemiology and its professional relevance to them than were students in the traditional course. PBL students worked more steadily during the semester but spent only marginally more time on the epidemiology course overall. Interviews corroborated these findings. Non-consenting students were older (p < 0.02) and more likely to come from non-English-speaking backgrounds (p < 0.005). Conclusions. PBL provides an academically equivalent but personally far richer learning experience. The adoption of PBL approaches to medical education makes it important to study whether PBL presents particular challenges for students whose first language is not the language of instruction.

Promoting physical activity among middle-aged and older adults in health care settings

Physical inactivity continues to be a significant public health issue for middle-aged and older adults. This review focuses on physical activity interventions targeting older adults in health care settings. The literature in this area is limited and the results to date disappointing. Much remains to be done to develop effective interventions targeting older adults, especially those from underserved groups. Attention also needs to be paid to maintenance of initial treatment gains and to linking primary-care-based physical activity interventions to community-based resources. Recognition in the social and behavioral sciences of the importance of social-environmental influences on health and health behaviors mandates both a multidisciplinary and a multilevel intervention approach to the problem of physical inactivity.

Heroin-assisted treatment as a response to the public health problem of opiate dependence

Injection drug use (involving the injection of illicit opiates) poses serious public health problems in many countries. Research has indicated that injection drug users are at higher risk for morbidity in the form of HIV/AIDS and Hepatitis B and C, and drug-related mortality, as well as increased criminal activity. Methadone maintenance treatment is the most prominent form of pharmacotherapy treatment for illicit opiate dependence in several countries, and its application varies internationally with respect to treatment regulations and delivery modes. In order to effectively treat those patients who have previously been resistant to methadone maintenance treatment, several countries have been studying and/or considering heroin-assisted treatment as a complementary form of opiate pharmacotherapy treatment. This paper provides an overview of the prevalence of injection drug use and the opiate dependence problem internationally, the current opiate dependence treatment landscape in several countries, and the status of ongoing or planned heroin-assisted treatment trials in Australia, Canada and certain European countries.

Effects of alkalis, oxidants and urea on the nutritive value of rhodes grass (Chloris gayana cv. Callide)

Two in sacco experiments were conducted to evaluate the impact on the nutritive value of rhodes grass hay (Chloris gayana cv. Callide) of treatment with alkalis or oxidants. In Experiment 1, three alkalis (Ca(OH)(2), NaOH, CaO) and two oxidants (NaOCl and H2O2) were applied at levels of 0, 20, 40, 60 or 80 g/kg of dry matter (DM). NaOH, Ca(OH)(2) and CaO had negative linear effects (P < 0.05) on the neutral detergent fibre (NDF) content and positive linear effects (P < 0.05) on the 48 h in sacco disappearances of DM, organic matter (OM), NDF and acid detergent fibre (ADF). NaOCl reduced (P < 0.05) NDF content but had no effect (P > 0.05) on the in sacco disappearances. H2O2 had no effect (P > 0.05) on the composition or digestibility of rhodes grass hay. In Experiment 2, effects of urea (0, 20, 40, 60 and 80 g urea/kg DM) and water (250, 500 and 750 g/kg DM) treatment of rhodes grass hay were examined in a 5 x 3 factorial experiment. Significant interactions between water and urea (P < 0.05) occurred for concentrations of crude protein (CP) and NDF, and 48 h in sacco disappearances of DM, OM (OMD) and NDE The combinations of water (g/kg DM) and urea (g/kg DM) that resulted in the highest concentrations of CP (281 g/kg DM) and OMD (747 g/kg DM) were 250 + 80 and 500 + 80, respectively. NaOH, Ca(OH)(2), CaO and urea significantly alter the NDF content and digestibility of rhodes grass hay, and urea also increases its CP content. Overall, NaOH was the most efficacious, followed by Ca(OH)(2), CaO, urea, NaOCl and H2O2. Crown Copyright (C) 2002 Published by Elsevier Science B.V. All rights reserved.

Scope for further analytical solutions for constant flux infiltration into a semi-infinite soil profile or redistribution in a finite soil profile

[1] We attempt to generate new solutions for the moisture content form of the one-dimensional Richards' [1931] equation using the Lisle [1992] equivalence mapping. This mapping is used as no more general set of transformations exists for mapping the one-dimensional Richards' equation into itself. Starting from a given solution, the mapping has the potential to generate an infinite number of new solutions for a series of nonlinear diffusivity and hydraulic conductivity functions. We first seek new analytical solutions satisfying Richards' equation subject to a constant flux surface boundary condition for a semi-infinite dry soil, starting with the Burgers model. The first iteration produces an existing solution, while subsequent iterations are shown to endlessly reproduce this same solution. Next, we briefly consider the problem of redistribution in a finite-length soil. In this case, Lisle's equivalence mapping is generalized to account for arbitrary initial conditions. As was the case for infiltration, however, it is found that new analytical solutions are not generated using the equivalence mapping, although existing solutions are recovered.

Group theory and quasiprobability integrals of Wigner functions

The integral of the Wigner function of a quantum-mechanical system over a region or its boundary in the classical phase plane, is called a quasiprobability integral. Unlike a true probability integral, its value may lie outside the interval [0, 1]. It is characterized by a corresponding selfadjoint operator, to be called a region or contour operator as appropriate, which is determined by the characteristic function of that region or contour. The spectral problem is studied for commuting families of region and contour operators associated with concentric discs and circles of given radius a. Their respective eigenvalues are determined as functions of a, in terms of the Gauss-Laguerre polynomials. These polynomials provide a basis of vectors in a Hilbert space carrying the positive discrete series representation of the algebra su(1, 1) approximate to so(2, 1). The explicit relation between the spectra of operators associated with discs and circles with proportional radii, is given in terms of the discrete variable Meixner polynomials.

Designing teams for first-of-a-kind, complex systems using the initial phases of cognitive work analysis: Case study

We present a technique for team design based on cognitive work analysis (CWA). We first develop a rationale for this technique by discussing the limitations of conventional approaches for team design in light of the special characteristics of first-of-a-kind, complex systems. We then introduce the CWA-based technique for team design and provide a case study of how we used this technique to design a team for a first-of-a-kind, complex military system during the early stages of its development. In addition to illustrating the CWA-based technique by example, the case study allows us to evaluate the technique. This case study demonstrates that the CWA-based technique for team design is both feasible and useful, although empirical validation of the technique is still necessary. Applications of this work include the design of teams for first-of-a-kind, complex systems in military, medical, and industrial domains.

A model of seller holdout

We model a buyer who wishes to combine objects owned by two separate sellers in order to realize higher value. Sellers are able to avoid entering into negotiations with the buyer, so that the order in which they negotiate is endogenous. Holdout occurs if at least one of the sellers is not present in the first round of negotiations. We demonstrate that complementarity of the buyer's technology is a necessary condition for equilibrium holdout. Moreover, a rise in complementarity leads to an increased likelihood of holdout, and an increased efficiency loss. Applications include patents, the land assembly problem, and mergers.

The initial effects of a Mulligan's mobilization with movement technique on dorsiflexion and pain in subacute ankle sprains

Physiotherapists frequently use manipulative therapy techniques to treat dysfunction and pain resulting from ankle sprain. This study investigated whether a Mulligan's mobilization with movement (MWM) technique improves talocrural dorsiflexion, a major impairment following ankle sprain, and relieves pain in subacute populations. Fourteen subjects with subacute grade II lateral ankle sprains served as their own control in a repeated measures, double-blind randomized controlled trial that measured the initial effects of the MWM treatment on weight bearing dorsiflexion and pressure and thermal pain threshold. The subacute ankle sprain group studied displayed deficits in dorsiflexion and local pressure pain threshold in the symptomatic ankle. Significant improvements in dorsiflexion occurred initially post-MWM (F-(2,F-26) 7.82, P = 0.002), but no significant changes in pressure or thermal pain threshold were observed after the treatment condition. Results indicate that the MWM treatment for ankle dorsiflexion has a mechanical rather than hypoalgesic effect in subacute ankle sprains. The mechanism by which this occurs requires investigation if we are to better understand the role of manipulative therapy in ankle sprain management. (C) 2003 Elsevier Ltd. All rights reserved.

Naloxone fails to antagonize initial hypoalgesic effect of a manual therapy treatment for lateral epicondylalgia

Background: Recent research has shown that Mulligan's Mobilization With Movement treatment technique for the elbow (MWM), a peripheral joint mobilization technique, produces a substantial and immediate pain relief in chronic lateral epicondylalgia (48% increase in pain-free grip strength).(1) This hypoalgesic effect is far greater than that previously reported with spinal manual therapy treatments, prompting speculation that peripheral manual therapy treatments may differ in mechanism of action to spinal manual therapy techniques. Naloxone antagonism and tolerance studies, which employ widely accepted tests for the identification of endogenous opioid-mediated pain control mechanisms, have shown that spinal manual therapy-induced hypoalgesia does not involve an opioid mechanism. Objective: The aim of this study was to evaluate the effect of naloxone administration on the hypoalgesic effect of MWM. Methods: A randomized, controlled trial evaluated the effect of administering naloxone, saline, or no-substance control injection on the MWM-induced hypoalgesia in 18 participants with lateral epicondylalgia. Pain-free grip strength, pressure pain threshold, thermal pain threshold, and upper limb neural tissue provocation test 2b were the outcome measures. Results: The results demonstrated that the initial hypoalgesic effect of the MWM was not antagonized by naloxone, suggesting a nonopioid mechanism of action. Conclusions: The studied peripheral mobilization treatment technique appears to have a similar effect profile to previously studied spinal manual therapy techniques, suggesting a nonopioid-mediated hypoalgesia following manual therapy.

The game to play: expanding the co-opetition proposal through the strategic games matrix

Purpose - Using Brandenburger and Nalebuff`s 1995 co-opetition model as a reference, the purpose of this paper is to seek to develop a tool that, based on the tenets of classical game theory, would enable scholars and managers to identify which games may be played in response to the different conflict of interest situations faced by companies in their business environments. Design/methodology/approach - The literature on game theory and business strategy are reviewed and a conceptual model, the strategic games matrix (SGM), is developed. Two novel games are described and modeled. Findings - The co-opetition model is not sufficient to realistically represent most of the conflict of interest situations faced by companies. It seeks to address this problem through development of the SGM, which expands upon Brandenburger and Nalebuff`s model by providing a broader perspective, through incorporation of an additional dimension (power ratio between players) and three novel, respectively, (rival, individualistic, and associative). Practical implications - This proposed model, based on the concepts of game theory, should be used to train decision- and policy-makers to better understand, interpret and formulate conflict management strategies. Originality/value - A practical and original tool to use game models in conflict of interest situations is generated. Basic classical games, such as Nash, Stackelberg, Pareto, and Minimax, are mapped on the SGM to suggest in which situations they Could be useful. Two innovative games are described to fit four different types of conflict situations that so far have no corresponding game in the literature. A test application of the SGM to a classic Intel Corporation strategic management case, in the complex personal computer industry, shows that the proposed method is able to describe, to interpret, to analyze, and to prescribe optimal competitive and/or cooperative strategies for each conflict of interest situation.

Multicollinearity and financial constraint in investment decisions: a Bayesian generalized ridge regression

This paper addresses the investment decisions considering the presence of financial constraints of 373 large Brazilian firms from 1997 to 2004, using panel data. A Bayesian econometric model was used considering ridge regression for multicollinearity problems among the variables in the model. Prior distributions are assumed for the parameters, classifying the model into random or fixed effects. We used a Bayesian approach to estimate the parameters, considering normal and Student t distributions for the error and assumed that the initial values for the lagged dependent variable are not fixed, but generated by a random process. The recursive predictive density criterion was used for model comparisons. Twenty models were tested and the results indicated that multicollinearity does influence the value of the estimated parameters. Controlling for capital intensity, financial constraints are found to be more important for capital-intensive firms, probably due to their lower profitability indexes, higher fixed costs and higher degree of property diversification.

The food business environment and the role of China and Brazil building a ""food bridge""

Purpose - The purpose of this paper is to discuss the economic crisis of 2008/2009 and the major impacts on developing nations and food-producing countries Within this macro-environment of food chains, there is concern that food inflation might come back sooner than expected The role of China as one of the major food consumers in the future, and Brazil, as the major food producer, is described as the food bridge, and an agenda of common development of these countries suggested. Design/methodology/approach - This paper reviews literature on muses of food inflation, production shortages, and investigation of programs to solve the problem in the future, it is also based on author`s personal insights and experience of working on this field in the last 15 years, and recent discussions in forums and interviews Findings - The major factors that jointly caused food prices increase in 2007/2008 were population growth, Income distribution, urbanization, dollar devaluations, commodity funds, social programs, production shortages, and bionic`s A list of ten policies is suggested. horizontal expansion of food production, vertical expansion, reduction in transaction costs, in protectionism and other taxes, investment in logistics, technology and better coordination, contracts, new generation of fertilizers and to use the best sources of biofuels. Originality/value - Two major outputs from this paper are the ""food demand model"" that inserts in one model the trends and muses of food inflation and the solutions, and the ""food bridge concept"" that also aligns in one box the imminent major food chain cooperation between China and Brazil