Modelling of unexpected shift in SPC

Optimal statistical process control (SPC) requires models of both in-control and out-of-control process states. Whereas a normal distribution is the generally accepted model for the in-control state, there is a doubt as to the existence of reliable models for out-of-control cases. Various process models, available in the literature, for discrete manufacturing systems (parts industry) can be treated as bounded discrete-space Markov chains, completely characterized by the original in-control state and a transition matrix for shifts to an out-of-control state. The present work extends these models by using a continuous-state Markov chain, incorporating non-random corrective actions. These actions are to be realized according to the SPC technique and should substantially affect the model. The developed stochastic model yields a Laplace distribution of a process mean. An alternative approach, based on the Information theory, also results in a Laplace distribution. Real-data tests confirm the applicability of a Laplace distribution for the parts industry and show that the distribution parameter is mainly controlled by the SPC sample size.     

Self-Perceived Parental Role and Mental Health Concomitants Among Israeli Gay and Heterosexual Fathers

ABSTRACT

In this study we examined the association between self-perceived parental role and adverse mental health (indicated by depressive symptoms, neuroticism, and negative affect) in a sample of 82 Israeli gay fathers (Mean age = 39.57, SD = 6.70) that were individually matched with 82 heterosexual fathers (Mean age = 39.11, SD = 7.88). Results showed that although self-perceived parental role was associated with adverse mental health, this association was moderated by sexual orientation, such that a significant negative association between self-perceived parental role and adverse mental health was evident only among gay fathers. The findings are understood by features of gay fatherhood, which is intentional and purposeful, and usually achieved after contending with particular difficulties in the journey to fatherhood. These features presumably shape the perceived parental role, and thus may link more strongly with lower levels of adverse mental health among gay fathers, compared to heterosexual fathers.     

Mass immigration and population dynamics in israel

Israel, in her 25 years of existence, received an unprecedented volume of immigration, which was the major source of her high population growth. This immigration was heavily concentrated in the first five years, 1948-1952; mass immigration of 711,000 supplemented an initial population of 630;000. Subsequently, since 1952, a very peculiar age-sex structure has developed: namely, instead of a pyramid, a wide rectangle for the younger age groups "topped" with a narrow pyramid for the older age groups. The peculiar age-sex dynamics is analyzed in relation to the volume of immigration with its uneven time distribution, the age selectivity of migrants and fertility-mortality patterns of migrants. It is concluded that the uneven time distribution of immigration and the higher fertility of migrants are jointly responsible for the development of Israel's peculiar age dynamics, and that the absence of either of these two factors alone would eliminate it. The peculiar dynamics has societal implications in the short and the long run, some of which are discussed.     

Collective consumption models with restricted bargaining weights: an empirical assessment based on experimental data

We use experimental data to analyze consumption decisions by groups of individuals who have to reach a consensus on spending a joint budget. Our experiment involves dyads (i.e. two-member groups) who have to compose consumption bundles consisting of three commodities (wine, orange juice and M&Ms). We focus on the collective consumption model to describe group behavior. This model represents group decisions as Pareto optimal outcomes of a within-group bargaining process, with rational group members who are each characterized by individual bargaining weights. We also consider specifications of the collective model that restrict the variation of these bargaining weights. A distinguishing feature of our study is that we use revealed preference testing tools to assess the goodness-of-fit and discriminatory power of alternative specifications of the collective model. Our experimental results suggest that the most appropriate model specification allows for a limited variation of the bargaining weights.     

Turkish Migrants and Native Germans Compared: The Effects of Inter‐Ethnic and Intra‐Ethnic Friendships on the Transition from Unemployment to Work

In this paper, we analyse whether having inter‐ethnic and intra‐ethnic friendships can be associated with a shorter duration of unemployment, comparing Turkish migrants and native residents in Germany. This allows us to examine the degree to which the returns from bridging and bonding social capital differ for the two groups. On the basis of the German Socio‐Economic Panel (GSOEP) data, we find that for native Germans, intra‐ethnic friendships shorten the duration of spells of unemployment, whereas inter‐ethnic friendships do not. For the Turkish migrants, inter‐ethnic friendships reduce the duration of unemployment, whereas intra‐ethnic friendships do not. In other words, only friendships with German natives facilitate the transition to employment, but in particular for Turkish migrants. This effect is largest for migrants with a low level of education.     

Freedom at the fringes? Slave flight and empire-building in the early modern Spanish borderlands of Essequibo–Venezuela and Louisiana–Texas

In spaces of contested sovereignty, self-emancipated slaves exploited imperial rivalries to attain freedom, based on the Spanish religious sanctuary. However, the status of foreign escaped slaves always remained subject to issues of empire-building. This article focuses on fugitive slaves from the Dutch colony of Essequibo and territorial Louisiana looking for freedom at the southern and northern borderlands of the Spanish empire, respectively, in Venezuela and Texas. In the former, increased Spanish control over the borderland created more opportunities for ‘runaways’. In the latter, improvisation led to erratic policies, related to pressure from US planters.     

THE “SALES AGENT” PROBLEM: EFFORT/LEISURE ALLOCATION UNDER PERFORMANCE PAY AS BEHAVIOR TOWARDS RISK

The choice between safe and risky assets represents behavior towards risk: more risk‐averse investors buy more safe assets. We develop and test a general model that applies this intuition to the time allocation between risky effort and risk‐free leisure under linear incentives. When risk increases with effort, risk‐averse agents choose less effort, but when risk is independent of effort, effort choice is unaffected by risk preferences. In many incentive contracts, income risk is multiplicative with, rather than additive to effort, sales commissions being one example. In such cases, lower effort by the risk‐averse is a hitherto undocumented behavior towards risk (JEL C91, M52, J33)