Choice procedure consistent with similarity relations

We deal with the approach, initiated by Rubinstein, which assumes that people, when evaluating pairs of lotteries, use similarity relations. We interpret these relations as a way of modelling the imperfect powers of discrimination of the human mind and study the relationship between preferences and similarities. The class of both preferences and similarities that we deal with is larger than that considered by Rubinstein. The extension is made because we do not want to restrict ourselves to lottery spaces. Thus, under the above interpretation of a similarity, we find that some of the axioms imposed by Rubinstein are not justified if we want to consider other fields of choice theory. We show that any preference consistent with a pair of similarities is monotone on a subset of the choice space. We establish the implication upon the similarities of the requirement of making indifferent alternatives with a component which is zero. Furthermore, we show that Rubinstein's general results can also be obtained in this larger class of both preferences and similarity relations.The nontransitiveness of indifference must be recognized and explained on any theory of choice and the only explanation that seems to work is based on the imperfect powers of discrimination of the human mind whereby inequality becomes recognizable only when of sufficient magnitude.     

An autoregressive process with geometric α-laplace marginals

Geometric Laplace and geometric α-Laplace distributions are studied and certain limit properties are derived. An autoregressive process with geometric Laplace stationary marginal distribution is introduced and its properties are studied. These results are generalized to geometric α-Laplace case also and applications are discussed.     

Mental Health of Non-gamblers Versus “Normal” Gamblers Among American Indian Veterans: A Community Survey

Goal This analysis was undertaken to assess the demographic and mental health characteristics of “normal” or non-problem gamblers versus non-gamblers in a representative community sample. Sample Study participants consisted of 557 North Central American Indian veterans. Data collection included a demographic and trauma questionnaire, a computer-based Diagnostic Interview Schedule for DSM-III-R, and a treatment history algorithm. Findings Univariate analyses revealed that gamblers had greater social competence (i.e., higher education, living with a spouse) and higher lifetime psychiatric morbidity. Binary regression analysis revealed that, compared to non-gamblers, gamblers were older, more highly educated, and more apt to be married. More gamblers showed evidence for lifetime risk-taking as evidenced by Antisocial Personality Disorder and Tobacco Dependence. Conclusions Social achievement and disposable income function as prerequisites for “normal” gambling in this population, although “externalizing” or “risk-taking” disorders also serve as independent contributors to at least some gambling. The increased rate of “internalizing” or emotional disorders are only indirectly related to gambling, perhaps through increasing age or through the “externalizing” disorders.     

Educational disparities across regions: A multilevel analysis for Italy and Spain

In this paper, a multilevel analysis is applied to the OECD-PISA2006 data with the aim to compare factors affecting students’ achievement across Italy and Spain. The findings show that both countries are affected by strong internal regional heterogeneity, where some regions have achievement scores well above the OECD mean and other are placed among the worst performers in the OECD area. Although regional governments are more autonomous about educational policy-making in Spain, regional indicators exert a higher influence on educational results in Italy where educational system is strictly regulated by the national government.     

Modelling the Inverse Association between Breastfeeding and Contraceptive Use

Previous studies of the inverse association between breastfeeding and contraceptive use have relied on current status data on at least one of the variables. In this paper we suggest a new way of modelling the joint temporal association of the adoption of contraception and the termination of breastfeeding over the course of a birth interval. The approach is implemented with survey data from rural Mexico. It involves first estimating a competing-risks model in which both hazards are considered simultaneous, together with a set of relevant covariates. Conditional analyses are then carried out to estimate the hazards of each event conditional on the timing of the other. By comparing the covariates, we gauge the extent to which the occurrence of one event raises or lowers the hazard of the other. The results show that, in rural Mexico, the timing of the termination of breastfeeding and that of starting contraceptive use are closely related, and that there exists a surprisingly neat interval of 120 days in which the action takes place.     

Generalized order statistic processes and Pfeifer records

We introduce a uniform generalized order statistic process. It is a simple Markov process whose initial segment can be identified with a set of uniform generalized order statistics. A standard marginal transformation leads to a generalized order statistic process related to non-uniform generalized order statistics. It is then demonstrated that the nth variable in such a process has the same distribution as an nth Pfeifer record value. This process representation of Pfeifer records facilitates discussion of the possible limit laws for Pfeifer records and, in some cases, of sums thereof. Because of the close relationship between Pfeifer records and generalized order statistics, the results shed some light on the problem of determining the nature of the possible limiting distributions of the largest generalized order statistic.     

Do Central Bank Liquidity Facilities Affect Interbank Lending Rates?

In response to the global financial crisis that started in August 2007, central banks provided extraordinary amounts of liquidity to the financial system. To investigate the effect of central bank liquidity facilities on term interbank lending rates near the start of the crisis, we estimate a six-factor arbitrage-free model of U.S. Treasury yields, financial corporate bond yields, and term interbank rates. This model can account for fluctuations in the term structure of credit and liquidity spreads observed in the data. A significant shift in model estimates after the announcement of the liquidity facilities suggests that these central bank actions did help lower the liquidity premium in term interbank rates.     

Change points in nonparametric regresion functions

Estimators of location and size of jumps or discontinuities in a regression function and/or its derivatives are proposed. The estimators are based on the analysis of residuals obtained from the locally weighted least squares regression. The proposed estimators adapt to both fixed and random designs. The asymptotic properties of the estimators are investigated. The method is illustrated through simulation studies.