Reduced Risk-Taking After Prior Losses in Pathological Gamblers Under Treatment and Healthy Control Group but not in Problem Gamblers

A group of pathological gamblers and a group of problem gamblers (i.e., gamblers at risk of becoming pathological) were compared to healthy controls on their risk-taking propensity after prior losses. Each participant played both the Balloon Analogue Risk Taking task (BART) and a modified version of the same task, where individuals face five repeated predetermined early losses at the onset of the game. No significant difference in risk-taking was found between groups on the standard BART task, while significant differences emerged when comparing behaviors in the two tasks: both pathological gamblers and controls reduced their risk-taking tendency after prior losses in the modified BART compared to the standard BART, whereas problem gamblers showed no reduction in risk-taking after prior losses. We interpret these results as a sign of a reduced sensitivity to negative feedback in problem gamblers which might contribute to explain their loss-chasing tendency.     

The role of education in the reconciliation between female occupation and family responsibilities at mid-life: the Italian case

This study, based on the data from the Survey of Health, Ageing and Retirement in Europe, deals with the labour market participation of mid-aged women and the reconciliation with family responsibilities. The analysis focuses on Italy, a fast ageing country with a very low female occupation rate. By performing a comparison with Sweden and France, we set three European models, different in terms of welfare system and gender roles, against each other. Women’s educational attainment is shown to be the most important factor associated with being in the labour market between 50 and 59 years old in all the countries analysed. Our findings suggest a couple-oriented approach to study women’s balancing of career and family: for married women, husbands’ education plays an ambivalent role concerning women's participation in the labour market, according to its combination with wives’ resources. The depressive effect on female employment of living close to a parent in poor health holds especially in Italy, suggesting the need to invest more on welfare policies in this country.     

A Probabilistic Methodology for the Assessment of Safety from Dropped Loads in Offshore Engineering

Pipeline damage by dropped objects from crane activities is a significant hazard for offshore platform installations. In this paper a probabilistic methodology is utilized for the estimation of the pipeline impact and rupture frequencies; this information is obtained both for the overall pipeline section exposed to the hazard and for a number of critical locations along the pipeline route. The presented algorithm has been implemented in a computer program that allows the analysis of a large number of possible drop points and pipeline target point locations. This methodology may be used in common risk analysis studies for evaluating the risk for platform personnel from dropped objects; however, the proposed technique may also be useful for other applications where engineering judgment has so far been the main driving criterion. In particular, two sample cases have been analyzed. The first one is the problem of selecting the best approaching route to a platform. By analyzing different route alternatives, a reduction of the impact frequency and therefore of the risk for the platform personnel may be achieved. The second application deals with the selection of the location for a safety valve at the riser base. The analysis may give useful information, such as the highest impact frequency location and the rupture frequencies upstream and downstream of the valve as a function of the valve position; this information, together with the transported medium inventory upstream of the valve, may give the designer a documented and justifiable rationale for selecting the best location for the valve from a safety point of view.     

Modeling healthcare costs in simultaneous presence of asymmetry,heteroscedasticity and correlation

Highly skewed outcome distributions observed across clusters are common in medical research. The aim of this paper is to understand how regression models widely used for accommodating asymmetry fit clustered data under heteroscedasticity. In a simulation study, we provide evidence on the performance of the Gamma Generalized Linear Mixed Model (GLMM) and log-Linear Mixed-Effect (LME) model under a variety of data-generating mechanisms. Two case studies from health expenditures literature, the cost of strategies after myocardial infarction randomized clinical trial on the cost of strategies after myocardial infarction and the European Pressure Ulcer Advisory Panel hospital prevalence survey of pressure ulcers, are analyzed and discussed. According to simulation results, the log-LME model for a Gamma response can lead to estimations that are biased by as much as 10% of the true value, depending on the error variance. In the Gamma GLMM, the bias never exceeds 1%, regardless of the extent of heteroscedasticity, and the confidence intervals perform as nominally stated under most conditions. The Gamma GLMM with a log link seems to be more robust to both Gamma and log-normal generating mechanisms than the log-LME model.     

Survival Trees: An Alternative Non-Parametric Multivariate Technique for Life History Analysis

In this paper an extension of tree-structured methodology to cover censored survival analysis is discussed. Tree-based methods (also called recursive partitioning) provide a useful alternative to the classical survival data analysis techniques, such as the semi-parametric model of Cox, whenever the main purpose is defining groups of individuals, either with complete or censored life history, having different survival probability, based on the values of selected covariates. The essential feature of recursive partitioning is the construction of a decision rule in the form of a binary tree. Trees generally require fewer assumptions than classical methods and handle non standard and non linear data structures efficiently. Tree-growing methods make the processes of covariate selection and grouping of categories in event history models explicit. An example concerning the analysis of time to marriage of Italian women is presented.     

A new 'biased coin design' for the sequential allocation of two treatments

Summary.  Efron's biased coin design is a well-known randomization technique that helps to neutralize selection bias in sequential clinical trials for comparing treatments, while keeping the experiment fairly balanced. Extensions of the biased coin design have been proposed by several researchers who have focused mainly on the large sample properties of their designs. We modify Efron's procedure by introducing an adjustable biased coin design, which is more flexible than his. We compare it with other existing coin designs; in terms of balance and lack of predictability, its performance for small samples appears in many cases to be an improvement with respect to the other sequential randomized allocation procedures.     

A sociological economy of HIV/AIDS vaccine partnerships: case studies from Africa and India

Public–private partnerships (PPPs) are perhaps the key emergent theme in the delivery of what the socio-economic literature terms global public goods. In light of the problems relating to the distribution of health services and products in developing countries, partnerships between public and private institutions are often proposed as an innovative mechanism to reconnect and reorient supply and demand. In this area, the International Aids Vaccine Initiative (IAVI), which is driving the development of candidate HIV/AIDS vaccines through injections of capital into the research process, represents a significant case study. IAVI seeks to form partnerships between key public and private interests committing them to sharing the risks, costs and benefits of research into an effective and affordable vaccine against HIV. Our empirical work covers partnerships based in several countries including Kenya, Uganda, Rwanda and India. Our early findings highlight IAVI's ability as a learning institution as it adapts its institutional arrangements to various local contexts. An offshoot of this appears to be the building of real local capacity.     

A theoretical analysis of the power of biased coin designs

Outlining some recently obtained results of Hu and Rosenberger [2003. Optimality, variability, power: evaluating response-adaptive randomization procedures for treatment comparisons. J. Amer. Statist. Assoc. 98, 671–678] and Chen [2006. The power of Efron's biased coin design. J. Statist. Plann. Inference 136, 1824–1835] on the relationship between sequential randomized designs and the power of the usual statistical procedures for testing the equivalence of two competing treatments, the aim of this paper is to provide theoretical proofs of the numerical results of Chen [2006. The power of Efron's biased coin design. J. Statist. Plann. Inference 136, 1824–1835]. Furthermore, we prove that the Adjustable Biased Coin Design [Baldi Antognini A., Giovagnoli, A., 2004. A new “biased coin design” for the sequential allocation of two treatments. J. Roy. Statist. Soc. Ser. C 53, 651–664] is uniformly more powerful than the other “coin” designs proposed in the literature for any sample size.     

“Good” corporate governance and the quality of internal auditing departments in Italian listed firms. An exploratory investigation in Italian listed firms

One of the most important issue relating to corporate governance reports refers to their ability to provide users with a complete set of information regarding the effective ability of an entity to achieve oversight objectives by the compliance to corporate governance practices required by a specific law or industry code. In addition, other features, such as the quality of the internal auditing function or the sensitivity of top management to issues relating to corporate internal controls and risk management, can also be taken into account when formulating a judgment on the quality of corporate governance practices. Is there an association between the compliance to codes and internal controls effectiveness? We propose to assess the quality of corporate governance through a proxy that considers several characteristics of internal audit departments and combines them to determine an Internal Audit Departments global quality index—IAD Index. To define IAD global quality we consider the effectiveness of an internal audit function analysing its operational aspects. The IAD Index is based on several signalling elements that previous literature assumed as proxies for quality of IADs which are grouped into four pillars: a formal quality index; a static quality index; an activity-related quality index; and a performance-linked quality index. We then test the IAD index on a sample of Italian listed firms and conclude that there are significant associations (positive and negative) between the degree of compliance to some corporate governance regulations for listed firms and the IAD Index for the sample being considered.     

Recursive Equilibrium in Stochastic Overlapping‐Generations Economies

We prove the generic existence of a recursive equilibrium for overlapping‐generations economies with uncertainty. “Generic” here means in a residual set of utilities and endowments. The result holds provided there is a sufficient number of potentially different individuals within each cohort.