Markoff-Rosenberger triples in arithmetic progression

We study the solutions of the Rosenberg--Markoff equation ax^2+by^2+cz^2 = dxyz (a generalization of the well--known Markoff equation). We specifically focus on looking for solutions in arithmetic progression that lie in the ring of integers of a number field. With the help of previous work by Alvanos and Poulakis, we give a complete decision algorithm, which allows us to prove finiteness results concerning these particular solutions. Finally, some extensive computations are presented regarding two particular cases: the generalized Markoff equation x^2+y^2+z^2 = dxyz over quadratic fields and the classic Markoff equation x^2+y^2+z^2 = 3xyz over an arbitrary number field.Comment: To appear in Journal of Symbolic Computatio

A New Approach for Bounding Awards in Bankruptcy Problems

The solution for the "Contested Garment Problem" proposed in the BabylonicTalmud, one of the most important sources of inspiration for solving situations where demand overcomes supply of some resources, suggests that each agent should receive at least some part of the available amount when facing these situations. Thisidea has been underlied the theoretical analysis of bankruptcy problems from its beginning (O'Neill, 1982) to present day (Dominguez and Thomsom, 2006). In this context, starting from the fact that a society establishes its own set of "Commonly Accepted Equity Principles", we propose a new award bound by providing each agent her minimum amount according to all the admissible bankruptcy rules for such a society. Moreover, we analyze the recursive application of this new bound, since it will not exhaust the resources, in general.Bankruptcy problems, bankruptcy rules, lower bound, recursive process.

Health status and retirement decisions for older European couples

In this paper we use data the European Community Household Panel (ECHP) to describe and analyse the dynamics of joint labour force behaviour of older couples for the EU12 countries. We focus on three main issues: the relevance of joint retirement across EU12 countries, the existence of complementarities in leisure and/or assortative matting and the effects of health variables. Concerning the evidence, we first find that a working spouse is more likely to retire the more recently the other spouse has retired; this effect is stronger if the wife is the working spouse. Second, there is evidence of assortative mating and/or complementarities in leisure; the effects of all relevant factors on the retirement decision of one spouse depend strongly on whether the other one is working, unemployed, or retired. Third, besides the standard evidence that poor health increases the retirement probability, we find that the husband's health affects the couple's retirement decisions much more strongly than the wife's health does. Additional asymmetric effects are detected with respect to income related variables.joint retirement decisions ; labour force transitions ; health variables ; asymmetric effects

Next Generation Quantitative Genetics in Plants

Most characteristics in living organisms show continuous variation, which suggests that they are controlled by multiple genes. Quantitative trait loci (QTL) analysis can identify the genes underlying continuous traits by establishing associations between genetic markers and observed phenotypic variation in a segregating population. The new high-throughput sequencing (HTS) technologies greatly facilitate QTL analysis by providing genetic markers at genome-wide resolution in any species without previous knowledge of its genome. In addition HTS serves to quantify molecular phenotypes, which aids to identify the loci responsible for QTLs and to understand the mechanisms underlying diversity. The constant improvements in price, experimental protocols, computational pipelines, and statistical frameworks are making feasible the use of HTS for any research group interested in quantitative genetics. In this review I discuss the application of HTS for molecular marker discovery, population genotyping, and expression profiling in QTL analysis

Health status and retirement decisison for older european couples.

In this paper we use data the European Community Household Panel (ECHP) to describe and analyse the dynamics of joint labour force behaviour of older couples for the EUI2 countries. We focus on three main issues: the relanvance of joint retirement across EUI2 countries, the existence of complementarities in leisure and/or assortative matting and the effects of health variables. Concerning the evidence, we first find that a working spouse is more likely to retire the more recently the other spouse has retired; this effect is stronger if the wife is the working spouse. Second, there is evidence of assortative mating and/or complementarities in leisure; the effects of all relevant factors on the retirement decision of one spouse depend strongly on whether the other one is working, unemployed, or retired. Third, besides the standard evidence that poor health increases the retirement probabiliby, we find that the husband's health affects the couple's retirement decisions much more strongly than the wife's health does. Additional asymmetric effects are detected with respect to income related variables.Joint retirement decisions; Labour force transitions; Health variables; Asymmetric effects;

An Empirical Analysis of the Demand for Physician Services Across the European Union

This paper presents parameter estimates for physician services equations using the European Community Household Panel for 12 countries covering the period 1994-1996. The focus is on two specific points: i) the identification of behavioural similarities and differences in the demand for health across the countries; ii) the variability of the demand for health captured through a joint model for all the countries. We find that there are significant differences across countries, although there are also similarities in the effect of variables such as the health stock, labour situation or family structure. An important fraction of the variability of the demand of health services across countries could be explained from differences in age, income, and the role of General Practitioners (GP) as a gatekeepers in the public health system. We also find some evidence of induced demand effects in both the decision to visit and the number of visits to specialists.count data; demand; physician services; latent class model; two-part model

Award errors and permanent disability benefits in Spain

There is a controversial debate about the effects of permanent disability benefits on labor market behavior. In this paper we estimate equations for deserving and receiving disability benefits to evaluate the award error as the difference in the probability of receiving and deserving using survey data from Spain. Our results indicate that individuals aged between 55 and 59, self-employers or working in an agricultural sector have a probability of receiving a benefit without deserving it significantly higher than the rest of individuals. We also find evidence of gender discrimination since male have a significantly higher probability of receiving a benefit without deserving it. This seems to confirm that disability benefits are being used as an instrument for exiting the labor market for some individuals approaching the early retirement or those who do not have right to retire early. Taking into account that awarding process depends on Social Security Provincial Department, this means that some departments are applying loosely the disability requirements for granting disability benefits.Disability benefits, Award error, Early retirement, Social security

A sequential model for older workers’ labor transitions after a health shock

In this work we study older workers’ (50—64) labor force transitions after a health/disability shock. We find that the probability of keeping working decreases with both age and severity of the shock. Moreover, we find strong interactions between age and severity in the 50—64 age range and none in the 30–49 age range. Regarding demographics we find that being female and married reduce the probability of keeping work. On the contrary, being main breadwinner, education and skill levels increase it. Interestingly, the effect of some demographics changes its sign when we look at transitions from inactivity to work. This is the case of being married or having a working spouse. Undoubtedly, leisure complementarities should play a role in the latter case. Since the data we use contains a very detailed information on disabilities, we are able to evaluate the marginal effect of each type of disability either in the probability of keeping working or in returning back to work. Some of these results may have strong policy implications.Health shocks, disability, labor force transitions, older workers, Spain