On the Relationships between Sum Score Based Estimation and Joint Maximum Likelihood Estimation

This paper analyzes the sum score based (SSB) formulation of the Rasch model, where items and sum scores of persons are considered as factors in a logit model. After reviewing the evolution leading to the equality between their maximum likelihood estimates, the SSB model is then discussed from the point of view of pseudo-likelihood and of misspecified models. This is then employed to provide new insights into the origin of the known inconsistency of the difficulty parameter estimates in the Rasch model. The main results consist of exact relationships between the estimated standard errors for both models; and, for the ability parameters, an upper bound for the estimated standard errors of the Rasch model in terms of those for the SSB model, which are more easily available. The authors acknowledge partial financial support from the FONDECYT Project No. 1060722 from the Chilean Government, and the BIL05/03 grant to P. De Boeck, E. Lesaffre and G. Molenberghs (Flanders) for a collaboration with G. del Pino, E. San Martín, F. Quintana and J. Manzi (Chile).     

Personality, gender and violent criminality in prison inmates

The Antisocial Personality Questionnaire developed by Blackburn and Fawcett (1999) has shown adequate reliability and validity in studies of male offenders interned in psychiatric hospitals. This paper provides data on the APQ collected from a sample of offenders (males and females) without any diagnosed mental illness. The sample was made up of 216 offenders (108 males and 108 females) confined in Spanish prisons. We analyzed the psychometric properties of the instrument and we also examined differences in personality as a function of gender and type of crime (violent vs. non-violent). Results support the reliability of the APQ scales as well as the structure proposed by Blackburn. Additionally, we selected items that discriminate between offenders convicted for violent and non-violent crimes; when these items are factorized, a three-factor structure emerges, resembling Eysenck's model.     

Relationship between quantity and frequency of alcohol use and indices of suicidal behavior in an elderly Australian sample

Relatively little research has been conducted on the relationship between alcohol misuse and suicidal behavior among the elderly. The current study's aim was to examine whether quantity and frequency of alcohol use and the interaction between these variables are related to current suicidal ideation, previous suicidal ideation/intent, and past suicide attempts in a community sample of 1,010 Australian adults over age 60. Results partially supported our hypotheses. The interaction between quantity and frequency of alcohol use was significant, suggesting that those who use alcohol less frequently but in greater quantities (i.e., binge drinking) are more likely to have a history of suicide attempts.     

mTOR signaling in the hippocampus is necessary for memory formation

It is widely accepted that the formation of long-term memory (LTM) requires mRNA translation, but little is known about the cellular mechanisms in the brain that regulate this process. Mammalian target of rapamycin (mTOR) is a key regulator of translational efficacy and capacity. Here, we show that LTM formation of one-trial inhibitory avoidance (IA) in rats, a hippocampus-dependent fear-motivated learning task, requires mTOR activation. IA training is specifically associated with a rapid increase in the phosphorylation state of mTOR and its substrate ribosomal S6 kinase (p70S6K). Bilateral intra-CA1 infusion of rapamycin, a selective mTOR inhibitor, 15 min before, but not immediately after training completely hinders IA LTM without affecting short-term memory (STM) retention. Therefore, our findings indicate that the regulation of hippocampal mRNA translation is a major control step in memory consolidation.     

Moral judgments, emotions and the utilitarian brain

The investigation of the neural and cognitive mechanisms underlying the moral mind is of paramount importance for understanding complex human behaviors, from altruism to antisocial acts. A new study on patients with prefrontal damage provides key insights on the neurobiology of moral judgment and raises new questions on the mechanisms by which reason and emotion contribute to moral cognition.     

Canonical Extensions and Relational Representations of Lattices with Negation

This work is part of a wider investigation into lattice-structured algebras and associated dual representations obtained via the methodology of canonical extensions. To this end, here we study lattices, not necessarily distributive, with negation operations.We consider equational classes of lattices equipped with a negation operation ¬ which is dually self-adjoint (the pair (¬,¬) is a Galois connection) and other axioms are added so as to give classes of lattices in which the negation is De Morgan, orthonegation, antilogism, pseudocomplementation or weak pseudocomplementation. These classes are shown to be canonical and dual relational structures are given in a generalized Kripke-style. The fact that the negation is dually self-adjoint plays an important role here, as it implies that it sends arbitrary joins to meets and that will allow us to define the dual structures in a uniform way.Among these classes, all but one—that of lattices with a negation which is an antilogism—were previously studied by W. Dzik, E. Or?owska and C. van Alten using Urquhart duality.In some cases in which a given axiom does not imply that negation is dually self-adjoint, canonicity is proven with the weaker assumption of antitonicity of the negation.     

Is the attribution of cultural differences to minorities an expression of racial prejudice?

The social psychological literature considers two main perspectives on the study of perceived cultural differences between majorities and minorities: one proposes that perception of cultural differences is an antecedent of prejudice and another states that the attribution of cultural differences to minorities is already a hidden expression of racial prejudice. This paper offers further support to this latter perspective. One hundred and ninety-four participants answered a questionnaire measuring (1) general racist belief; (2) cultural differences attributed to Black people (hetero-ethnicization); (3) the asymmetric attribution of secondary and primary emotions to the in-group and to Black people (infra-humanization); (4) the asymmetric attribution of natural and cultural traits to in-group members and to Black people (ontologization); and (5) negative evaluation of this social category. The general racist belief scale was not anchored in a specific group and measured the belief in the inferiority of certain social groups or peoples based on biological or cultural factors. Relationships between the scales were analysed through a set of Structural Equation Models. According to the predictions, results showed that the attribution of cultural differences is a dimension of prejudice. Results also showed that attribution of cultural differences, negative evaluation of Black people, ontologization, and infra-humanization were different dimensions of a common latent factor that can be identified as racial prejudice; and that prejudice was predicted by general racist belief. Results are discussed in the light of the study of the impact of perceived cultural differences on intergroup relations and in the light of the "new racism" approaches.