Learning in a navigation task: The role of salience of pairs of landmarks and sex differences

In two experiments rats were trained to find an invisible platform in the presence of four objects or landmarks which were centred at equal intervals around the edge of the pool. One pair of landmarks had more intrinsic salience than the other pair: The relative proximal from the platform landmarks were those with more intrinsic salience in Experiment 1 and those with less intrinsic salience in Experiment 2. In Experiment 1, the two proximal from the platform and with more intrinsic salience landmarks prevented learning about the two relatively distal from the platform and with less intrinsic salience landmarks. No sex differences were found. In Experiment 2, the two relatively distal and with more intrinsic salience landmarks did not prevent learning about the two proximal but with less intrinsic salience landmarks. No sex differences were found after extended training. These results could have implications to understand spatial overshadowing among landmarks

Aprendizaje en una tarea de navegación: el papel de la saliencia de pares de puntos de referencia y diferencias de sexo

In two experiments rats were trained to find an invisible platform in the presence of four objects or landmarks which were centred at equal intervals round the edge of the pool. One pair of landmarks had more intrinsic salience than the other pair: The relative proximal from the platform landmarks were those with more intrinsic salience in Experiment 1 and those with less intrinsic salience in Experiment 2. In Experiment 1, the two proximal from the platform and with more intrinsic salience landmarks prevented learning about the two relatively distal from the platform and with less intrinsic salience landmarks. No sex differences were found. In Experiment 2, the two relatively distal and with more intrinsic salience landmarks did not prevent learning about the two proximal but with less intrinsic salience landmarks. No sex differences were found after extended training. These results have implications to understand spatial overshadowing among landmarks.En dos experimentos se entrenó a unas ratas a encontrar una plataforma oculta en presencia de cuatro objetos o puntos de referencia, centrados a inter-valos regulares alrededor del borde de la piscina. Una pareja de puntos de referencia tenía mayor saliencia intrínseca que el otro par: los objetos más próximos de la plataforma eran los que tenían más saliencia intrínseca en el Experimento 1 y los que tenían menos en el Experimento 2. En el Experimento 1, los dos objetos más próximos de la plataforma y con más saliencia intrínseca impidieron el aprendizaje de los dos objetos más alejados de la plataforma y con menos saliencia intrínseca. No se encontraron diferencias de sexo. En el Experimento 2 los dos objetos más alejados de la plataforma y con más saliencia intrínseca no impidieron el aprendizaje de los dos objetos más próximos de la plataforma aunque con menos saliencia intrínseca. No se encontraron diferencias de sexo con un entrenamiento prolongado. Estos resultados tienen implicaciones para entender el ensombrecimiento espacial entre puntos de referencia

Landmark learning in a navigation task is not affected by the female rats' estrus cycle

In two experiments rats were required to escape from a circular pool by swimming to an invisible platform that was located in the same place relative to one configuration of two landmarks (X and Y). The two landmarks were placed relatively far and equidistant from the hidden platform. Training could be either on consecutive days (Experiment 1) or every fourth day (Experiment 2). Subsequent test trials, without the platform, revealed a preference for searching in the correct quadrant of the pool. In Experiment 1 such a test performance was identical in two groups of females, one tested with high hormonal levels (i.e., in the proestrus phase) and the second one tested with low hormonal levels (i.e., either in the estrus, metaestrus or diestrus phase); in addition, these two groups differed from a third group of male rats (i.e., males had a better performance than females). Experiment 2 replicated the females' previous results with a better procedure. The experiment compared the performance of two groups of female rats which were both trained and tested always in the same estrus phase, one group in the proestrus phase, and the second group in the estrus phase. The implication of these results is that the estrus cycle has little impact on the performance of female rats when landmark learning in a navigation task

«A daring feat»: pioneering women directors of the Portuguese press in the United States - historical and socio-symbolic aspects

The main objective of this study is to give greater visibility to the female immigrant journalists who pioneered Portuguese newspapers within the United States. It also contributes to the restoration of their collective memories, lending special attention to some socially significant moments of symbolic value, so as to understand their remarkable roles within the Portuguese-American press. Their stories reveal the efforts of these women who strove to make a career in the world of journalism, and their determination and dignity, despite their socio-cultural origins from immigrant communities with rural roots, mostly in the Azores Islands. The male-dominated society of both the Portuguese diaspora and the USA meant that the inherent discrimination of cultural and social stereotyping relegated female roles to positions of inferiority and submission. Expected to forego higher education, they were often pushed into low-skilled jobs, even while caring for children and working as housewives. Through a qualitative methodology, based on the scarce few available archival resources, the lives of women who worked as editors of the Portuguese press in the United States are set in an historical perspective. Finally, the most representative aspects are presented of two of the most singular and paradigmatic pioneers of Portuguese journalism in the United States, Laurinda C. Andrade and Mary Nunes Silveira, respectively, the editors of A Tribuna Portuguesa (New Jersey) and the Jornal Português (California), through a discussion of their biographies and their professional careers

Evaluation of VDR gene polymorphisms in Trypanosoma cruzi infection and chronic Chagasic cardiomyopathy

Vitamin D is an important modulator of the immune response. It acts over several immune cell types where the Vitamin D receptor (VDR) is expressed. Due to the high relevance of this signaling pathway, several studies have investigated the possible influence of genes involved in the metabolism of Vitamin D and its receptor in different human diseases. Here, we analyzed whether four single-nucleotide polymorphisms of the VDR gene (rs731236, rs7975232, rs1544410 and rs2228570) are involved in the susceptibility to infection by Trypanosoma cruzi and/or to chronic Chagas cardiomyopathy (CCC) in a Colombian endemic population for this parasite. Our results showed that the rs2228570*A allele is associated with CCC development (P = 4.46E−03, OR = 1.51). In summary, the data presented in this report suggest that variation within the VDR gene may affect the immune response against T. cruzi, increasing the probability of cardiac complications in infected individuals.Peer reviewe

Conceptual multidimensionality in medical translation

En la comunicación científica, la selección de un término suele conllevar que se resalte una característica más o menos prototípica del concepto, una intención en el emisor o una dimensión del concepto. En la comunicación interlingüística y a menudo intercultural que entraña la traducción en ámbitos biosanitarios, prestar atención a estas dimensiones es importante para que el producto cumpla con las expectativas del receptor meta. El proyecto VARIMED (FFI2011-23120) se plantea estudiar la motivación cognitiva que existe en la selección léxica de distintas formas para dar nombre a conceptos médicos de cara a establecer la presencia de una sistematización en dicha motivación. En este artículo abordaremos estas características desde la descripción de los objetivos del proyecto y la metodología seguida en el mismo.In scientific communication, selecting a term often means highlighting a more or less prototypical feature of a concept, revealing an intention from the issuer or even a certain facet of the concept. It is particularly important to pay due attention to such facets or conceptual dimensions in the process of interlinguistic and intercultural mediation implied by biomedical translation so that the text matches the target audience expectations. The project VariMed (FFI2011-23120) attempts to study the cognitive motivation underlying the lexical selection of different denominative variants for medical concepts in order to find patterns which explain the causes or motivation for terminological variation. This paper deals with the communicative and cognitive motivation from the point of view of the objectives and the methodology followed in VariMed

Nonlinear resonances of an idealized saccular aneurysm

This paper investigates the occurrence of dynamic instabilities in idealized intracranial saccular aneurysms subjected to pulsatile blood flow and surrounded by cerebral spinal fluid. The problem has been approached extending the original 2D model of Shah and Humphrey (1999) to a 3D framework. The justification for using a 3D formulation arises from the works of Suzuki and Ohara (1978), MacDonald et al. (2000) and Costalat et al. (2011) who showed experimental evidences of intracranial aneurysms with a ratio between wall thickness and inner radius larger that 0.1. Two different material models have been used to describe the mechanical behaviour of the aneurysmal wall: Neo-Hookean and Mooney-Rivlin. To the authors' knowledge, for the first time in literature, the dynamic response of the aneurysm has been analysed using complete nonlinear resonance diagrams that have been obtained from a numerical procedure specifically designed for that purpose. Our numerical results show that, for a wide range of wall thicknesses and both constitutive models considered, the saccular aneurysms are dynamically stable within the range of frequencies associated to the normal heart rates, which confirms previous results of Shah and Humphrey (1999). On the other hand, our results also show that the geometric and material nonlinearities of the problem could bring closer than expected the resonance frequencies of the aneurysm to the frequencies of the pulsatile blood flow.The authors are indebted to the Spanish Ministry of Economy and Competitiveness (Project EUIN2015-62556) for the financial support received which allowed conducting part of this work

Male advantage in geometry learning? A preliminary study in rats.

¿Superioridad de los machos en el aprendizaje de la geometría? Un estudio preliminar con ratas: Se entrenó a ratas de forma sucesiva en tres inusuales laberintos acuáticos a encontrar una plataforma oculta que mantenía una relación constante con una esquina distintiva del aparato (i.e., piscina triangular, rectangular y con forma de cometa en los Experimentos 1-3, respectivamente). Tras cada fase de entrenamiento se llevó a cabo un ensayo de prueba, sin plataforma. En la prueba, en el Experimento 1 se registró el tiempo que pasaban las ratas en dos áreas diferentes, una frente a la esquina correcta y otra en la esquina opuesta e incorrecta. Este experimento replicó resultados anteriores: se encontró una clara superioridad de los machos en el aprendizaje de la geometría (Rodríguez y cols, 2010, 2011). En los Experimentos 2 y 3 se utilizaron medidas adicionales y, en ambos experimentos, las distintas medidas de aprendizaje espacial dieron resultados significativamente diferentes. La superioridad de los machos encontrada en el Experimento 1 no parece generalizarse bien a otras geometrías.Palabras Claves: Aprendizaje de la Geometría; Diferencias de Sexo; Laberinto Acuático; Ratas. Rats were successively trained in three unusual watermazes to find a hidden platform that always maintained a constant relationship with a distinctive corner of the apparatus (i.e., a triangular-shaped pool in Experiment 1, a rectangular-shaped pool in Experiment 2, and a kite-shaped pool in Experiment 3). After each training phase a test trial was conducted, without the platform. On test, in Experiment 1 the amount of time the rat spent in two different areas, one in front of the correct corner and one in exactly an opposite and incorrect corner was recorded. The experiment replicated previous results: a clear male advantage on geometry learning (Rodríguez et al., 2010, 2011). Additional measures were also employed in Experiments 2 and 3 and, in both experiments, the different measures of spatial learning gave quite different results. The male advantage found in Experiment 1 did not seem to generalize well to other geometries.Key Words: Geometry Learning; Sex Differences; Watermaze; Rats

IL18 Gene Variants Influence the Susceptibility to Chagas Disease

Chagas disease is a parasitic disorder caused by the infection with the flagellated protozoan Trypanosoma cruzi. According to the World Health Organization, more than six million people are currently infected in endemic regions. Genetic factors have been proposed to influence predisposition to infection and development of severe clinical phenotypes like chronic Chagas cardiomyopathy (CCC). Interleukin 18 (IL18) encodes a proinflammatory cytokine that has been proposed to be involved in controlling T. cruzi infection. In this study, we analyzed the possible role of six IL18 gene variants (rs5744258, rs360722, rs2043055, rs187238, rs1946518 and rs360719), which cover most of the variation within the locus, in the susceptibility to infection by T. cruzi and/or CCC. In total, 1,171 individuals from a Colombian region endemic for Chagas disease, classified as seronegative (n = 595), seropositive asymptomatic (n = 175) and CCC (n = 401), were genotyped using TaqMan probes. Significant associations with T. cruzi infection were observed when comparing seronegative and seropositive individuals for rs187238 (P = 2.18E-03, OR = 0.77), rs360719 (P = 1.49E-03, OR = 0.76), rs2043055 (P = 2.52E-03, OR = 1.29), and rs1946518 (P = 0.0162, OR = 1.22). However, dependence analyses suggested that the association was mainly driven by the polymorphism rs360719. This variant is located within the promoter region of the IL18 gene, and it has been described that it creates a binding site for the transcription factor OCT-1 affecting IL-18 expression levels. In addition, no evidence of association was observed between any of the analyzed IL18 gene polymorphisms and the development of CCC. In summary, our data suggest that genetic variation within the promoter region of IL18 is directly involved in the susceptibility to infection by T. cruzi, which provides novel insight into disease pathophysiology and adds new perspectives to achieve a more effective disease control.This work is part of the doctoral thesis “Estudio de las bases genéticas de la enfermedad de Chagas” from the Biomedicine PhD program at the Universidad de Granada (Spain).Peer reviewe

Landmark vs. geometry learning: Explaining female rats' selective preference for a landmark

Rats were trained in a triangular-shaped pool to find a hidden platform, whose location was defined in terms of two sources of information, a landmark outside the pool and a particular corner of the pool. Subsequent test trials without the platform pitted these two sources of information against one another. In Experiment 1 this test revealed a clear, although selective, sex difference. As in previous experiments, females spent more time in an area of the pool that corresponded to the landmark, but here only when it was a cone but not when it was a pyramid. Males, on the other hand, always spent more time in the distinctive corner of the pool. Experiments 2 and 3 were only with female rats. In Experiment 2 two identical shaped cylinders were used as landmark cues (one plain white and the other vertically patterned with four different patterns). The results of the preference test revealed that only the females trained and tested with the plain cylinder spent more time in the area of the pool that corresponded to the landmark than in the distinctive corner of the pool. Finally, Experiment 3 replicated the results of Experiment 2 while eliminating an alternative explanation in terms of differential contrast between the two cylinders and the black curtain