Robust Model Selection for Stochastic Processes

We address the problem of robust model selection for finite memory stochastic processes. Consider m independent samples, with most of them being realizations of the same stochastic process with law Q, which is the one we want to retrieve. We define the asymptotic breakdown point γ for a model selection procedure and also we devise a model selection procedure. We compute the value of γ which is 0.5, when all the processes are Markovian. This result is valid for any family of finite order Markov models but for simplicity we will focus on the family of variable length Markov chains.     

Social Work Gerontological Practice: The Need for Faculty Development in the New Millennium

There is a pressing need to upgrade the gerontological knowledge and skills of practicing social workers. Geriatrics and gerontology, as specialized fields of knowledge, have not been sufficiently integrated into formal academic training programs. There are major trends in the health care environment which impact on social work education, including technological advances, a shift from inpatient to outpatient and community care settings, increasing diversity of the older population, and client and family participation in decisionmaking. These trends necessitate social work education to emphasize new content areas in gerontology and the development of new skills in clinical, case management, care coordination, and teamwork. A significant obstacle to the preparation of future social workers to deliver the complex services needed by older adults and their families is a serious shortage of social work faculty in gerontology. Sustained and broad initiatives, such as the John A. Hartford Foundation funded Geriatric Social Work Faculty Scholars Program, are needed to develop academic and practice-based faculty in gerontology. This is crucial if social work is to maintain an important service role in the new millennium.     

Bias correction for time series factor models

In this paper we work with multivariate time series that follow a Factor Model. In particular, we consider the setting where factors are dominated by highly persistent AutoRegressive (AR) processes and samples that are rather small. Therefore, the factors' AR models are estimated using small sample bias correction techniques. A Monte Carlo study reveals that bias-correcting the AR coefficients of the factors allows to obtain better results in terms of prediction interval coverage. As expected, the simulation shows that bias-correction is more successful for smaller samples. We present the results assuming the AR order and number of factors are known as well as unknown. We also study the advantages of this technique for a set of Industrial Production Indexes of several European countries.     

The "X component" in Shanghai's social security reforms

In 2003, the Shanghai Bureau of Labour and Social Security launched the zhenbao (town insurance) programme, now widely known as 25 plus X. This scheme is regarded as an important experiment in social security reform and has been lauded for extending social security to areas where previously only segments of the population had mandatory coverage. Using data from 103,000 individuals enrolled in 25 plus X, we examine the extent to which the scheme represents an extension in social security coverage. Our analysis suggests that while it does represent an extension of benefits for some, for many it represents a considerable dilution in benefits.     

Improving health care delivery to aging adults with disabilities: social work with dual eligibles in a climate of health care reform

Adults aging with disabilities comprise a diverse group. In this article, we identify the prevalence and characteristics of this target population, focusing on adults who are dually eligible for Medicare and Medicaid. We articulate challenges in the delivery of health, social, and support services to adults aging with disabilities, particularly how existing health care policy and financing contributes to fragmentation of care. Finally, we identify opportunities for social workers to advocate for and promote system improvements in the delivery of care for aging adults with disabilities in the current climate of health care reform.     

Coalitional Interval Games for Strategic Games in Which Players Cooperate

We propose a method to associate a coalitional interval game with each strategic game. The method is based on the lower and upper values of finite two-person zero-sum games. Associating with a strategic game a coalitional interval game we avoid having to take either a pessimistic or an optimistic approach to the problem. The paper makes two contributions to the literature: It provides a theoretical foundation for the study of coalitional interval games and it also provides, studies, and characterizes a natural method of associating coalitional interval games with strategic games.      

The grieving child: Manifest and hidden losses in childhood and adolescence

The loss of parents through abandonment has specific traumatic features. This paper discusses the variety of losses children and adolescents may experience and the psychological implications and manifestations in relation to the loss. Specific reactions of children and suggestions for therapeutic prevention through psychotherapy are discussed.Coordinator, Ph.D. Specialization in treatment of children and adolescents and is in private practice     

MEN, WOMEN, AND THE CULTURE OF ENGINEERING

This study focuses on women's position in engineering. A conflict model that emphasizes the interplay of structural and interactional resources is developed to explain the occupational positions of women engineers. A central feature of this model is the "culture of engineering"—the socially defined standard of behavior and interaction among engineers. This model is used to explain the occupational experiences of a cohort of male and female engineers. Males and females with virtually identical qualifications and occupational attitudes show dissimilar current job status. It is argued that the culture of engineering, strongly identified with the male gender role, works against women. Where that culture is strongest, women do most poorly in occupational status and mobility.     

Managing risk under the children act 1989: Diversion in child care?

The idea of diversion has dominated the theory and practice of juvenile justice for some time. Developments in child care practice in the 1980s mirror those which produced diversion. Diversion provides an alternative conceptual framework within which the changes to child care law introduced by the Children Act 1989 can be analysed, particularly the interrelation of s.1(5), the so-called non-intervention principle, and Part III, which establishes the duty of local authorities to provide services for children in need. These provisions and current child care practices may be seen to promote four distinct forms of diversion: (1) diversion from court; (2) diversion from care or residential provision; (3) diversion from procedures; and (4) diversion from social work. Examining the law and practice in terms of diversion focuses on the potential gains and losses resulting from the Children Act's emphasis on partnership, planning and bureaucracy without presuming that losses will be compensated for by the provision of services. It also suggests the need to consider child care in terms of net widening and tariff raising.     

A Simulation Study of the Influence of Study Design on the Estimation of Benchmark Doses for Developmental Toxicity1

The benchmark dose (BMD)⁴ approach is emerging as replacement to determination of the No Observed Adverse Effect Level (NOAEL) in noncancer risk assessment. This possibility raises the issue as to whether current study designs for endpoints such as developmental toxicity, optimized for detecting pair wise comparisons, could be improved for the purpose of calculating BMDs. In this paper, we examine various aspects of study design (number of dose groups, dose spacing, dose placement, and sample size per dose group) on BMDs for two endpoints of developmental toxicity (the incidence of abnormalities and of reduced fetal weight). Design performance was judged by the mean-squared error (reflective of the variance and bias) of the maximum likelihood estimate (MLE) from the log-logistic model of the 5% added risk level (the likely target risk for a benchmark calculation), as well as by the length of its 95% confidence interval (the lower value of which is the BMD). We found that of the designs evaluated, the best results were obtained when two dose levels had response rates above the background level, one of which was near the ED₀₅, were present. This situation is more likely to occur with more, rather than fewer dose levels per experiment. In this instance, there was virtually no advantage in increasing the sample size from 10 to 20 litters per dose group. If neither of the two dose groups with response rates above the background level was near the ED₀₅, satisfactory results were also obtained, but the BMDs tended to be more conservative (i.e., lower). If only one dose level with a response rate above the background level was present, and it was near the ED₀₅, reasonable results for the MLE and BMD were obtained, but here we observed benefits of larger dose group sizes. The poorest results were obtained when only a single group with an elevated response rate was present, and the response rate was much greater than the ED₀₅. The results indicate that while the benchmark dose approach is readily applicable to the standard study designs and generally observed dose-responses in developmental assays, some minor design modifications would increase the accuracy and precision of the BMD.