When constraints interact: A caution about reference variables, identification constraints and scale dependencies in structural equation modeling.

In traditional approaches to structural equations modeling, variances of latent endogenous variables cannot be specified or constrained directly and, consequently, are not identified, unless certain precautions are taken. The usual method for achieving identification has been to fix one factor loading for each endogenous latent variable at unity. An alternative approach is to fix variances using newer constrained estimation algorithms. This article examines the philosophy behind such constraints and shows how their appropriate use is neither as straightforward nor as noncontroversial as portrayed in textbooks and computer manuals. The constraints on latent variable variances can interact with other model constraints to interfere with the testing of certain kinds of hypotheses and can yield incorrect standardized solutions with some popular software. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reliability and validity of the Jesness Inventory: A caution.

A 1-wk test–retest interval was used with 59 delinquent and 68 nondelinquent White male adolescents in studying the Jesness Inventory. The data show that the 10 individual subscales were unstable and that the Asocial Index had moderate stability for broad classification but not for specific raw scores. The Asocial Index, which is the major predictor of delinquency, failed to distinguish accurately the delinquents from the nondelinquents. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Power, politics, and psychotherapy: A constructive caution on unification.

This article considers what the costs and benefits of a unifying paradigm for psychotherapy might be and concludes that the potential risks and benefits of unification in psychotherapy depend critically on the kind of unification that is sought and how it is achieved. One form of unification operates at the level of particulars and the other at the level of general principles; there are also 2 means of achieving unity: 1 by force and 1 by flow. The American Psychological Association (APA) Publication Manual, the Diagnostic and Statistical Manual for Mental Disorders, and APA accreditation are 3 exemplars of forced unities that emphasize particulars. In contrast, flowing unifying principles can embrace the essential tensions of diverse theories' and different paradigms' partial truths without resorting to forcing specifics or foreclosing on alternative possibilities. We must be careful not to institutionalize unnecessary constraints on the free and flowing expression of therapeutic principles that lies at the heart of constructive practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Commentary: balancing life and death--proceed with caution

Fibrinogen is involved in platelet aggregation and clot formation. It is mainly synthesized by hepatocytes. The additional, small pool of this glycoprotein is known to exist in the alpha granules of bone marrow megakaryocytes and blood platelets. Up-date of the origin of fibrinogen in these cells has been discussed.     

A bit about haplotypes: using binary digits to code tightly linked loci

The advent of recombinant DNA techniques has resulted in the detection of a large number of polymorphic marker loci many of which are not useful for linkage studies because of their low degree of polymorphism. However, when no apparent recombination exists between several closely linked markers, the amount of 'information' available can be significantly increased by establishing haplotypes from those loci; that is, haplotyping increases the number of heterozygotes at marker loci. Haplotyping can be problematic when more than one of the loci involved in the haplotyping are heterozygous and the phase of the haplotypes cannot be inferred from the data. We present a method for recoding the phenotypic marker data for pedigree members that will circumvent this difficulty.