Navigating the Mental Lexicon: Network Structures, Lexical Search and Lexical Retrieval.

This paper examines the implications of the association patterns in our understanding of the mental lexicon. By applying the principles of graph theory to word association data, we intend to explore which measures tap better into lexical knowledge. To that end, we had different groups of English as Foreign language learners complete a lexical fluency task. Based on these empirical data, a study was undertaken on the corresponding lexical availability graph (LAG). It is observed that the aggregation (mentioned through human coding) of all lexical tokens on a given topic allows the emergence of some lexical-semantic patterns. The most important one is the existence of some key terms, featuring both high centrality in the sense of network theory and high availability in the LAG, which define a hub of related terms. These communities of words, each one organized around an anchor term, or most central word, are nicely apprehended by a well-known network metric called modularity. Interestingly enough, each module seems to describe a conceptual class, showing that the collective lexicon, at least as approximated by LA Graphs, is organised and traversed by semantic mechanisms or associations via hyponymy or hiperonymy, for instance. Another empirical observation is that these conceptual hubs can be appended, resulting in high diameters compared to same-sized random graphs; even so it seems that the small-world hypothesis holds in LA Graphs, as in other social and natural networks.

Suggestive linkage of schizophrenia to 5p13 in Costa Rica.

Schizophrenia afflicts roughly 1% of all people worldwide. Remarkably, despite differing cultures and environments, the expression of illness is essentially the same. Family, twin, and adoption studies identify schizophrenia as a genetically influenced disease. Linkage studies suggest many positive regions of interest, but as a complex genetic disorder most of the pathogenic loci have not yet been found. Isolated populations are commonly used to study rare Mendelian inherited diseases due to the more homogenous genetic background of the subjects and are thought to be useful for detecting linkage in complex genetic disorders such as schizophrenia. This study aims to define areas of the genome that exhibit co-inheritance with schizophrenia in one large, Mendelian-like family from the central valley of Costa Rica. The whole genome scan analysis of this pedigree, which included 11 cases of schizophrenia and schizoaffective disorder, identified a number of markers on chromosome 5p that appear to co-segregate with the disease with a maximum lod score of 2.70 at marker D5S426. Current studies include investigating additional Costa Rican pedigrees to replicate these findings and identify additional loci linked to the disease.

Nivel de resolución de un equipo de atención primaria: el "cuánto" como indicador del producto y el "qué" como instrumento de formación y mejora

Objetivo. Facilitar a los profesionales de los equipos de atención primaria (EAP) un instrumento de medida de la capacidad resolutiva que permita conocer la situación de cada equipo respecto a los de su misma gerencia o servicio de atención primaria (SAP) e identificar las oportunidades de mejora. Diseño. Estudio descriptivo transversal. Emplazamiento. Los 4 EAP del SAP Ciutat Vella del ámbito de Barcelona Ciutat (Institut Català de la Salut).Participantes. Todas las derivaciones para primera visita hechas por los profesionales de medicina general de todos los EAP durante el año 2001 a la atención especializada. Mediciones principales: Cuantitativas: número de derivaciones por cada 100 pacientes atendidos (ND); capacidad resolutiva (CR) = ND del EAP/ND del SAP. Cualitativas: motivo de derivación por especialidad y EAP (NDM) (número, porcentaje acumulado y tasa por 1.000 atendidos).Resultados. Se atendió a 55.399 personas y se produjeron 19.198 derivaciones, lo que representa un ND de 34,7/100 atendidos en el conjunto del SAP, que oscila entre las 29,7 del EAP menos derivador a las 41,6 del más derivador. La CR oscilaba desde 0,87 hasta 1,2. Las especialidades en que se observaba una mayor variabilidad en el comportamiento de los EAP eran neumología, neurología, digestología y reumatología. Conclusiones. La medición de la CR que proponemos es una forma eficiente y factible de complementar la medida del producto de un EAP y constituye un buen instrumento para orientar las estrategias de mejora en las especialidades en las que la CR es baja (AU)

Clinical characteristics of schizophrenia in multiply affected Spanish origin families from Costa Rica.

Sixty-six families from Costa Rica with multiply ill sets of siblings were examined in detailed clinical evaluations and compared with 59 similarly evaluated families from the USA. Eighty-six unrelated Costa Rican individuals with a schizophrenia spectrum diagnosis and no other ill siblings were an additional comparison group. This study was undertaken to examine whether schizophrenia in Costa Rica has similar clinical and demographic characteristics to that in the USA, whether a homogeneous population such as that in Costa Rica might harbor a specific definable subtype, and whether singletons have similar or differing characteristics from individuals in multiplex families. Overall, schizophrenia in Costa Rica is similar to that in any other geographic location. The same symptoms, sex ratio and age of onset characteristics predominate. However, there was significantly less prevalence of affective symptoms (depression and mania) and drug abuse among the Costa Rican multiplex families by comparison with those from the USA. The families with only one ill member from Costa Rica had significantly more alcohol abuse than the multiply affected families. Within multiplex families (both USA and Costa Rica), age of onset was found to have a familial component. Family sibship size was significantly greater in Costa Rica than the USA for the generation with illness studied. However, these siblings had overall fewer children. In Costa Rica, the male but not the female siblings with schizophrenia had reduced fecundity compared with their well siblings. These families from Costa Rica will be used in further molecular genetic studies to determine whether the illness etiology can be traced to one or more specific genetic linkages.

[Long and medium-term neuropsychological sequelae of bone marrow transplantation in pediatric patients with hematological disease]. / Secuelas neuropsicológicas a medio y largo plazo del trasplante de medula ósea en pacientes con enfermedades hematológicas.

BACKGROUND: Few studies exist on the neuropsychological sequelae of bone marrow transplantation (BMT) in pediatric patients. Published results show considerable discrepancies although studies of children with acute lymphoblastic leukemia undergoing high doses of cranial radiotherapy report short- and long-term loss of cognitive ability. OBJECTIVES: To determine the effects of BMT and the effect of anxiety on the pre-BMT assessment in a group of children with severe hematological disease treated in our center. METHODS: We performed a descriptive, prospective, longitudinal study of 54 children, aged 4-15 years, who were treated between 1987 and 1995. Twenty-two children were evaluated before and after BMT by means of the Weschler Intelligence Scale. To control for the effect of anxiety on the pre-BMT scores, the patients were divided into two groups according to the scores obtained in this test (group 1: IQ score 100; group 1: IQ100). RESULTS: Comparison of pre- and post-BMT scores for both groups revealed no significant differences. However, comparison of the results between groups revealed that group I scored lower in the post-BMT test than in the pre-BMT test while group I scored higher in the post-BMT test than in the pre-BMT test. CONCLUSIONS: Although comparison between the pre- and post-BMT results obtained from the whole sample showed no differences that indicated post-treatment sequelae, treatment-induced anxiety may have influenced the pre-BMT score.

Secuelas neuropsicológicas a medio y largo plazo del trasplante de medula ósea en pacientes con enfermedades hematológicas / Long and medium-term neuropsychological sequelae of bone marrow transplantation in pediatric patients with hematological disease

Antecedentes: Existen pocos estudios sobre las secuelas neurocognitivas del trasplante de medula ósea (TMO) en pacientes pediátricos, y sus resultados a menudo son divergentes, aunque los estudios con niños enfermos de leucemia sometidos a altas dosis de radioterapia craneal muestran pérdida de capacidad cognitiva a medio y largo plazo. Objetivos: Conocer los efectos del TMO en un grupo de niños con graves enfermedades hematológicas tratados en nuestro centro, y el impacto de la ansiedad en la evaluación previa al TMO. Métodos: Se realizó un estudio descriptivo prospectivo y longitudinal, desde 1987 hasta 1995 con un grupo 54 niños, de entre 4 y 15 años. De este grupo 22 niños se evaluaron antes y después del TMO mediante la Escala de Inteligencia de Wechsler para niños (Wechsler Intelligence Scale, WIS). Con el fin de controlar el impacto de la ansiedad sobre el rendimiento de la evaluación previa al TMO se dividieron los pacientes en 2 grupos según la puntuación obtenida en dicha evaluación: grupo 1, cociente de inteligencia total (CIT) menor o igual a 100; grupo 2, CIT mayor de 100. Resultados: En la comparación entre los resultados de los 2 grupos pretrasplante y postrasplante del grupo inicial no se observaron diferencias significativas, pero al comparar los resultados por grupos, se observó un descenso significativo en el grupo 2, el que había puntuado más alto en la evaluación previa al TMO, mientras que el grupo 1 aumentaba su rendimiento. Conclusiones: Si bien en una primera comparación entre los resultados pretrasplante y postrasplante de la muestra no parece existir diferencias que muestren secuelas postratamiento, la ansiedad producida por el mismo pudo haber influido en la evaluación pretrasplante, de tal forma que enmascarase los efectos de éste (AU)