MARKET POWER AND INFORMATION REVELATION IN DYNAMIC TRADING

We study a strategic model of dynamic trading where agents are asymmetrically informed over common value sources of uncertainty. There is a continuum of buyers and a finite number n of sellers. All buyers are uninformed, while at least one seller is privately informed about the true state of the world. When n = 1, full information revelation never occurs in equilibrium and the only information transmission happens in the first period. With n > 1 the outcome depends both on the structure of the sellers' information and, even more importantly, on the intensity of competition allowed by the existing trading rules. When there is intense competition (absence of clienteles), information is fully and immediately revealed to the buyers in every equilibrium for n large enough, regardless of the number of informed sellers. On the other hand, for trading arrangements characterized by less intense forms of competition (presence of clienteles), for any n we always have equilibria where information is never fully revealed. Moreover, in that case, when only one seller is informed, for many parameter configurations there are no equilibria with full information revelation, even for large n. (JEL: C72, C78, D82, D83)     

The Sex Check: The Development of an HIV-Prevention Service to Address the Needs of Latino MSM

The Sex Check is a brief, telephone-delivered, HIV-prevention intervention tailored for individuals who are at high risk of HIV infection or transmission but who are neither reducing their risk on their own nor seeking support for this purpose. Because the intervention is delivered on a one-to-one basis, permits anonymity, is marketed to "men who have sex with men," and is brief, it may be particularly responsive to cultural, structural, and attitudinal barriers to serving Latino MSM. Because many Latino MSM continue to engage in high risk sexual behaviors, developing and testing prevention interventions with this population is a public health priority.     

The Difficulties of Interculturalism

One can describe three hurdles on the road to building a multi‐ethnic society: under‐estimating the problem; the conflict between the need to respect a culture and the need to open it to another culture; the existence of unacceptable aspects of a specific culture in a universalistic framework. The article describes ways to overcome these difficulties: (a) a gradual process from multiculturalism towards interculturalism; (b) certain minimum conditions must be met at the material level (home, work, etc); (c) to encourage individuals and communities to lessen their physical and psychological distance and to show each other mutual respect (to which education can provide a contribution through the teaching of social sciences).     

WORKER POWER, FIRM POWER, AND THE STRUCTURE OF LABOR MARKETS

The purpose of this article is to advance the conceptual development of structurally-oriented approaches to stratification by elaborating a behavioral model of the structure of labor markets that is based on power relations among both individual and collective actors. After reviewing the various approaches to the study of stratification and enumerating some of its shortcomings, a theory of the operation of labor markets that synthesizes a number of the elements in extant theories is presented. A labor market typology is developed based on the relative power of firms and workers and four distinct types of markets are delineated, i.e., worker-controlled, firm-internal, worker-firm negotiated, and competitive. In addition, the dynamics by which these labor markets are transformed is discussed. It is argued that this conceptual framework solves a number of problems inherent in extant theories of the operation of labor markets and the article concludes by suggesting areas for future research based on the theory.     

Working Conditions and Health Among Italian Ageing Workers

In many European countries requirements for retirement have been tightened, causing an increase in work participation of older workers, in spite their potentially poorer health may limit their work ability. This study aimed at assessing the diffusion of health problems and exposure to unfavorable working conditions among ageing workers in two Italian surveys, as well as comparing them with those observed in the same surveys conducted before the 2011 Italian pension reform tightening the normal retirement age. The 2013 National Health Survey (NHS) and Labour Force Survey (LFS) were employed to assess the prevalence of poor perceived health, health conditions and functional limitations, and of exposure to physical, psychosocial and organization factors at work, among 60–64 years workers. Poisson regression models were used to estimate Prevalence Ratios of health outcomes and unfavorable working conditions in the two surveys, compared to data from the 2005 (NHS) and 2007 (LFS) corresponding surveys, respectively. Among both men and women, approximately one quarter had at least one physical disorder or functional limitations and 15% poor mental health. Exposure to different ergonomic factors (15–30%) and working during unsocial hours (19%) were particularly diffused. A significant increase in the prevalence of functional limitations and of working at night or during unsocial hours was found in 2013, compared to corresponding data from 2005 and 2007, respectively. Our results indicate that exposure to ergonomic and organizational hazards should be reduced among ageing workers, to avoid decreased work ability, health damage or early exit from the labour market.

     

Fractions of permutations. An application to Sudoku

We study how to simplify fractional factorial design generation by exploiting the a priori knowledge that can be derived from the orthogonality constraints that the fractional factorial design itself must satisfy. We work on Sudoku puzzles that can be considered as a special case of Latin squares in the class of gerechte designs. We prove that the generation of a Sudoku is equivalent to that of a fraction of a proper set of permutations. We analyse both the 4×4 and the 9×9 Sudoku types.     

Latent class models for ecological inference on voters transitions

This paper introduces some new models of ecological inference within the context of estimation of voter transitions across elections. In particular, we assume that voters of a given party in a given occasion may be split into two latent types: faithful voters, who will certainly vote again for the same party and movers, who will reconsider their choice. Our models allow for unobserved heterogeneity across polling stations both in the weights of the two latent classes within each party and also when modelling the choice of unfaithful voters. Different ways of modelling the unobserved heterogeneity are considered by exploiting properties of the Dirichlet-multinomial distribution and the Brown Payne model of voting transitions can be seen as a special case within the class of models presented here. We discuss pseudo-maximum likelihood estimation and present an application to recent elections in Italy.