Identifiability of nonlinear logistic test models

The linear logistic test model (LLTM) specifies the item parameters as a weighted sum of basic parameters. The LLTM is a special case of a more general nonlinear logistic test model (NLTM) where the weights are partially unknown. This paper is about the identifiability of the NLTM. Sufficient and necessary conditions for global identifiability are presented for a NLTM where the weights are linear functions, while conditions for local identifiability are shown to require a model with less restrictions. It is also discussed how these conditions are checked using an algorithm due to Bekker, Merckens, and Wansbeek (1994). Several illustrations are given.This article was written while the first author was a post doctoral fellow at the university of Twente. He gratefully acknowledges the university's hospitality and the financial support by NWO (project nr. 30002).     

A computational model of frontal lobe dysfunction: working memory and the Tower of Hanoi task

A symbolic computer model, employing the perceptual strategy, is presented for solving Tower of Hanoi problems. The model is calibrated—in terms of the number of problems solved, time taken, and number of moves made—to the performance of 20 normal subjects. It is then "lesioned" by increasing the decay rate of elements in working memory to model the performance of 20 patients with lesions to the prefrontal cortex. The model captures both the main effects of subject groups (patients and normal controls) performance, and the subject groups (patients and normal controls) by problem difficulty interactions. This leads us to support the working memory hypothesis of frontal lobe functions, but for a narrow range of problems.     

Scharffs' Application of Hopper's Concept: “Incohesion: Aggregation/Massification”

We begin by stating our understanding of the concepts presented in Hopper's paper, then comment on the clinical illustration, and conclude by describing two group situations in which we have applied the concepts we have taken from Hopper's paper. Hopper's fourth basic assumption applies to our work as individual psychoanalysts, family therapists, and group leaders because it integrates psychoanalytic and social understanding. We demonstrate how and why we find Hopper's idea to be a useful advance.     

The Possible Place of Cognitive Appraisal in the ABC Model Underlying Rational Emotive Behavior Therapy

In a critique of Ellis' Rational Emotive Behavior Therapy (REBT) theory of personality, it has been argued that, among other strategies, REBT personality theory could be significantly advanced by attempting to incorporate within it already established theoretical constructs compatible with the cognitive-behavioral movement. Richard Lazarus' prominent, well-articulated, and extensively studied theoretical construct of cognitive appraisal seems ideal in this regard. In the present article, the relevant and salient aspects of Lazarus' construct are described. An attempt is then made to delineate the possible place of cognitive appraisal in the ABC model underlying REBT. Finally, the clinical implications of this proposed ABC model refinement are then explored, and an additional REBT therapeutic strategy based upon the cognitive appraisal construct, reappraisal training, is suggested and briefly described.     

Palm Beach County Child Abuse and Neglect System Redesign: Initial Process Evaluation

For the families in Palm Beach County who entered the child abuse and neglect system as a result of having a child placed into emergency shelter, their experience was that the system was frequently intimidating, confusing, and fragmented. The reaction of the children and their families to this system was often defensiveness and resistance. To increase the system's effectiveness, it was redesigned and privatized. The redesigned system included centralized shelter placement, a comprehensive assessment, independent service coordination, and treatment service provision within a managed care model. By emphasizing family involvement and quality service provision, the goal was to increase voluntary participation and improve family outcomes. Based on initial data, it appears that the redesigned system has been successfully implemented and has made notable progress toward meeting its system flow timeframes. The initial data also indicate that high percentages of families are participating in and are satisfied with the system, that children are spending less time in shelter placements, and that only one family has reentered the system.     

Mentoring: Some ethical considerations

To counter confusion about the term ‘mentor’, and address concerns about the scarcity of mentoring, I argue for an “honorific” definition, according to which a mentor is virtuous like a saint or hero. Given the unbounded commitment of mentors, mentoring relationships must be voluntary. In contrast, the role of advisor can be specified, mandated, and monitored. I argue that departments and research groups have a moral responsibility to devise a system of roles and structures to meet graduate students’ and postdoctoral fellows’ needs for information and advice. An earlier version of this paper was presented at a conference sponsored by the National Science Foundation on Mentoring and Research Values: Students as Vital Human Resources, Chicago, March 1995.     

Mentors, advisors and supervisors: Their role in teaching responsible research conduct

Although the terms mentor and thesis advisor (or research supervisor) are often used interchangeably, the responsibilities associated with these roles are distinct, even when they overlap. Neither are role models necessarily mentors, though mentors are role models: good examples are necessary but not sufficient. Mentorship is both a personal and a professional relationship. It has the potential for raising a number of ethical concerns, including issues of accuracy and reliability of the information conveyed, access, stereotyping and tracking of advisees, and the abuse of power. Nevertheless, mentors can be critically important for professional success and are one of a number of elements that affect the responsible conduct of research. In addition, the community as a whole has a responsibility to mentor junior members. An earlier version of this paper was presented at a conference sponsored by the National Science Foundation on Mentoring and Research Values: Students as Vital Human Resources, Chicago, USA, March 1995.     

建立新一代的精神分裂症动物模型

精神分裂症动物模型的建立与发展,是当前探索精神分裂症的神经生物学和认知心理学机制的一个关键课题。在加工-保护理论的基础上所建立起来的感觉运动门控精神分裂症模型一直受到普遍的关注。然而,高级认知活动是如何对感觉门控进行调节的这一核心问题目前还有待进一步的解决。本综述围绕着这个核心问题,系统地解释为什么惊反射前脉冲抑制成为目前最为流行的一种精神分裂症的模型,并介绍恐惧情绪学习对感觉运动门控调节作用的最新研究成果,以及阐述这种自上而下的调节作用如何受到在早期发育阶段的社会隔离的影响     

心理疾病污名形成理论述评

心理疾病污名是加诸于患者身上的耻辱标记,妨碍患者的治疗和康复。心理疾病污名的成因理论包括功能主义和生物文化两个派别,污名的发展模型解释了污名的形成过程,身份威胁模型对污名的作用机制进行了阐述。通过抗议、教育和接触可以有效地减少污名。在中国开展相关研究应注重分析传统文化、心理疾病类型与污名的关系,探讨各种减少污名策略的可行性     

TAS-20 alexithymia in obesity, and its links to personality

We studied the association between alexithymia (20-item Toronto Alexithymia Scale, TAS-20) and obesity, and also assessed the construct validity of the TAS-20 in terms of personality dimensions in obese patients. The TAS-20 and its subscales were analysed for their correlations with the NEO Personality Inventory - Revised (NEO PI-R) in an obese sample of 259 patients. Obesity was associated with higher scores on the TAS-20 than a Swedish reference sample. Obese men furthermore scored higher on Externally Oriented Thinking than the obese women. TAS-20 scores correlated with elevated Neuroticism and lower levels of Extraversion and Openness, in agreement with most previous research, but also somewhat unexpectedly with lower Conscientiousness and for women also with lower Agreeableness. The TAS-20 subscales showed divergent associations with personality variables, largely in accordance with previous findings. The associations were more prominent for the women, and some gender-specific patterns not previously reported were also revealed.