Whither the virtuous cycle? Past and future trends in black-white inequality in educational attainment

The inequality in the relative years of education between blacks and whites has diminished dramatically over the 20th century. One possible explanation for this convergence is a virtuous cycle of parents passing on educational advantage, from one generation to the next, leading to an overall educational upgrading. In this paper we test the virtuous cycle hypothesis by estimating the three way interaction of cohort, race, and family background. We find that the convergence in educational attainment between blacks and whites over the past century was driven by processes unrelated to family background.     

Doubling up when times are tough: A study of obligations to share a home in response to economic hardship

This study uses a factorial vignette design embedded in an Internet survey to investigate attitudes toward an adult child and parent living together in response to economic hardship. Over half of Americans said the desirability of intergenerational co-residence depends on particularistic aspects of the family, notably the quality of family relationships. Support for co-residence is greatest when the adult child is single rather than partnered. Support is weaker if the adult child is cohabiting rather than married to the partner, although groups with greater exposure to cohabitation make less of a distinction between cohabitation and marriage. Presence of a grandchild does not affect views about co-residence. There is more support for sharing a home when a mother needs a place to live than when the adult child does. Responses to open-ended questions show that individuals invoke both universalistic family obligations and particularistic qualities of family relationships to explain their attitudes.     

Widening the social context of disablement among married older adults: Considering the role of nonmarital relationships for loneliness

Utilizing the stress process and life course perspectives, we investigated the influence of non-spousal social support on the associations between marital quality, physical disability, and loneliness among married older adults. Using data from the National Social Life, Health, and Aging Project (NSHAP), we found that the association between physical disability and loneliness was partially accounted for by the fact that physical disability was associated with less supportive nonmarital relationships. While physically-disabled older adults in higher-quality marriages were buffered from loneliness, supportive non-martial relationships did not offset elevated loneliness among those in low-quality marriages. These associations were largely similar for men and women. Thus, although both marital and nonmarital relationships are important for loneliness, when confronted with a stressor such as disablement it is the marital relationship alone that matters.     

Opinions toward suicide: Cross-national evaluation of cultural and religious effects on individuals

This study evaluates the role that religious and cultural values have on individual opinions toward suicide worldwide. Using multilevel modeling with data from the fourth wave of the World Values Survey (42,299 individuals in 43 countries), the current study is designed to analyze the effect of individual (i.e., micro-level), and country (i.e., macro-level) characteristics on opinions toward suicide. Specifically, cultural values, religious affiliation, religious importance, and church attendance are analyzed at both the individual and country levels to evaluate the impact of individual and country level effects on opinions toward suicide. The results show that individual opinions toward suicide are influenced by individual belief as well as by the cultural and religious characteristics of their country. The results suggest that evaluation of individual opinions toward controversial behavior should account for the unique and cross-interaction effects of micro- and macro-level effects.     

Bivariate Birnbaum-Saunders accelerated lifetime model: estimation and diagnostic analysis

In this paper, we discuss the bivariate Birnbaum-Saunders accelerated lifetime model, in which we have modeled the dependence structure of bivariate survival data through the use of frailty models. Specifically, we propose the bivariate model Birnbaum-Saunders with the following frailty distributions: gamma, positive stable and logarithmic series. We present a study of inference and diagnostic analysis for the proposed model, more concisely, are proposed a diagnostic analysis based in local influence and residual analysis to assess the fit model, as well as, to detect influential observations. In this regard, we derived the normal curvatures of local influence under different perturbation schemes and we performed some simulation studies for assessing the potential of residuals to detect misspecification in the systematic component, the presence in the stochastic component of the model and to detect outliers. Finally, we apply the methodology studied to real data set from recurrence in times of infections of 38 kidney patients using a portable dialysis machine, we analyzed these data considering independence within the pairs and using the bivariate Birnbaum-Saunders accelerated lifetime model, so that we could make a comparison and verify the importance of modeling dependence within the times of infection associated with the same patient.     

COST INCREASES DUE TO DEMAND UNCERTAINTY IN MRP LOT SIZING

This paper analyzes the cost increases due to demand uncertainty in single-level MRP lot sizing on a rolling horizon. It is shown that forecast errors have a tremendous effect on the cost effectiveness of lot-sizing techniques even when these forecast errors are small. Moreover, the cost differences between different techniques become rather insignificant in the presence of forecast errors. Since most industrial firms face demand uncertainty to some extent, our findings may have important managerial implications. Various simulation experiments give insight into both the nature and the magnitude of the cost increases for different heuristics. Analytical results are developed for the constant-demand case with random noise and forecasting by exponential smoothing. It is also shown how optimal buffers can be obtained by use of a simple model. Although the analysis in this paper is restricted to simplified cases, the results merit further consideration and study. This paper is one of the first to inject forecast errors into MRP lot-sizing research. As such it attempts to deal with one of the major objections against the practical relevance of previous research in this area.     

AN APPROXIMATION TO THE HYPERCUBE MODEL WITH PATROL-INITIATED ACTIVITIES: AN APPLICATION TO POLICE

This paper applies the patrol-initiated-activity hypercube queuing model to historical data from a police agency. The model allows servers to handle both calls assigned by a central dispatcher and activities initiated by the servers. By duplicating a fairly complex dispatch strategy, the model was found to predict both assigned and server-initiated work loads accurately for the overall system and individual servers. The model is apparently ineffective in predicting small unit-travel-time differences for this police agency.     

STOCHASTIC COST-VOLUME-PROFIT ANALYSIS WITH A LINEAR DEMAND FUNCTION

In this paper we incorporate a linear demand function to model the price-volume causal relationship into stochastic cost-volume-profit (CVP) analysis. We assume that the objective function is to maximize expected profit; other objective functions are also discussed and compared. A linear stochastic model follows from which probabilistic statements can be easily obtained if the random variables are assumed to be multivariate normal. The basic framework is shown to be a special case of project value maximization where project value is the cash flow of the project discounted for time and risk according to the capital asset pricing model. Moreover, an intertemporal extension that considers inventory is developed. In summary, a new approach to stochastic CVP analysis that incorporates the management decision process in an uncertain environment is developed.     

马尼拉、澳门、广州:紧密相联的三座城市

数百年来,马尼拉、澳门和广州一直相互依存,保持着密切关系。从16世纪后期至今,三者有着紧密的互动关系,每一城市对其他两者都有着深刻的影响与冲击。这些联系已经维系了几百年,直到今天仍有数万菲律宾人在珠江三角洲生活和工作。牛痘传入澳门和广州或许是巴尔米斯环球之旅的意外收获,但它也确实是三个地区之间长期密切关系的一个表现。在巴尔米斯来到珠江三角洲200周年之际,我们不应忘记三地人民之间在历史上的紧密关系,这一关系仍继续支持和维系着中菲两国,它也将把我们带向未来。     

FORECAST EVALUATION OF LIVINGSTON DATA ON INFLATION RATES AND INFLATION UNCERTAINTY*

Livingston data on expected inflation rates have been used extensively in the financial literature, especially in investgating the relationship between nominal interest rates and expected inflation rates; however, the data have not been subjected to a thorough analysis of forecast accuracy. The objective of this paper is to analyze the forecast properties of Livingston data using a wide variety of time and frequency domain methods over an extended sample period and for selected subperiods.