103 research outputs found

    Discreet element modeling of under sleeper pads using a box test

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    It has recently been reported that under sleeper pads (USPs) could improve ballasted rail track by decreasing the sleeper settlement and reducing particle breakage. In order to find out what happens at the particle-pad interface, discrete element modelling (DEM) is used to provide micro mechanical insight. The same positive effects of USP are found in the DEM simulations. The evidence provided by DEM shows that application of a USP allows more particles to be in contact with the pad, and causes these particles to transfer a larger lateral load to the adjacent ballast but a smaller vertical load beneath the sleeper. This could be used to explain why the USP helps to reduce the track settlement. In terms of particle breakage, it is found that most breakage occurs at the particle-sleeper interface and along the main contact force chains between particles under the sleeper. The use of USPs could effectively reduce particle abrasion that occurs in both of these regions

    VOLUMEN 16, NÚMERO 30 (1983-1984)

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    PROYECTO GEOTÉRMICO CHILES - CERRO NEGRO. Lozano, E.; Cruz, L.ZONAS HIDROGEOLÓGICAS DE COLOMBIA. Lobo-Guerrero, A.ESTUDIO GEOQUÍMICO Y PETROGRÁFICO DE ROCAS SUBVOLCÁNICAS ENTRE LA QUEBRADA CHIRAPOTO Y EL RÍO ARQUÍA (DEPARTAMENTO DE ANTIOQUIA Y CALDAS). SĂĄnchez, L. H.; Parra, R. A.; OrtĂ­z, F.GEOLOGÍA Y EXPERIENCIAS CONSTRUCTIVAS EN EL TÚNEL TUNJITA. Tejada, S. E.CONTRIBUCIÓN AL CONOCIMIENTO DEL PALEOZOICO SUPERIOR EN LA SECCIÓN QUETAME - VILLAVICENCIO. CortĂ©s, R.; De La Espriella, R.TECTÓNICA GRAVITACIONAL EN LA CORDILLERA ORIENTAL AL ESTE DE LA FALLA DE BOYACÁ (DEPARTAMENTO DE BOYACÁ). Reyes, Ch. I.AMBIENTES GEOLÓGICOS URANÍFEROS EN COLOMBIA. Ortega Montero, C

    VOLUMEN 16, NÚMERO 30 (1983-1984)

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    PROYECTO GEOTÉRMICO CHILES - CERRO NEGRO. Lozano, E.; Cruz, L.ZONAS HIDROGEOLÓGICAS DE COLOMBIA. Lobo-Guerrero, A.ESTUDIO GEOQUÍMICO Y PETROGRÁFICO DE ROCAS SUBVOLCÁNICAS ENTRE LA QUEBRADA CHIRAPOTO Y EL RÍO ARQUÍA (DEPARTAMENTO DE ANTIOQUIA Y CALDAS). SĂĄnchez, L. H.; Parra, R. A.; OrtĂ­z, F.GEOLOGÍA Y EXPERIENCIAS CONSTRUCTIVAS EN EL TÚNEL TUNJITA. Tejada, S. E.CONTRIBUCIÓN AL CONOCIMIENTO DEL PALEOZOICO SUPERIOR EN LA SECCIÓN QUETAME - VILLAVICENCIO. CortĂ©s, R.; De La Espriella, R.TECTÓNICA GRAVITACIONAL EN LA CORDILLERA ORIENTAL AL ESTE DE LA FALLA DE BOYACÁ (DEPARTAMENTO DE BOYACÁ). Reyes, Ch. I.AMBIENTES GEOLÓGICOS URANÍFEROS EN COLOMBIA. Ortega Montero, C

    Editors' introduction: neoliberalism and/as terror

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    The articles in this special issue are drawn from papers presented at a conference entitled “Neoliberalism and/as Terror”, held at the Nottingham Conference Centre at Nottingham Trent University by the Critical Terrorism Studies BISA Working Group (CSTWG) on 15-16 September 2014. The conference was supported by both a BISA workshop grant and supplementary funds from Nottingham Trent University’s Politics and International Relations Department and the Critical Studies on Terrorism journal. Papers presented at the conference aimed to extend research into the diverse linkages between neoliberalism and terrorism, including but extending beyond the contextualisation of pre-emptive counterterrorism technologies and privatised securities within relevant economic and ideological contexts. Thus, the conference sought also to stimulate research into the ways that neoliberalism could itself be understood as terrorism, asking - amongst other questions - whether populations are themselves terrorised by neoliberal policy. The articles presented in this special issue reflect the conference aims in bringing together research on the neoliberalisation of counterterrorism and on the terror of neoliberalism

    Shortened Version of the Token Test: Normative data for Spanish-speaking pediatric population

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    OBJECTIVE: To generate normative data for the Shortened Version of the Token Test in Spanish-speaking pediatric populations. METHOD: The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the Shortened Version of the Token Test as part of a larger neuropsychological battery. Shortened Version of the Token Test total scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses. RESULTS: The final multiple linear regression models showed main effects for age in all countries, such that score increased linearly as a function of age. In addition, age2 had a significant effect in all countries, except Guatemala and Puerto Rico. Models showed that children whose parent(s) had a MLPE >12 years obtained higher score compared to children whose parents had a MLPE ≀12 years in Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, Puerto Rico, and Spain. The child’s sex did not have an effect in the Shortened Version of the Token Test total score for any of the countries. CONCLUSIONS: This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate interpretation of the Shortened Version of the Token Test when used in pediatric populations

    Newly developed Learning and Verbal Memory Test (TAMV-I): Normative data for Spanish-speaking pediatric population

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    OBJECTIVE: To generate normative data for the Learning and Verbal Memory Test (TAMV-I) in Spanish-speaking pediatric populations. METHOD: The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the TAMV-I as part of a larger neuropsychological battery. Free recall, memory delay and recognition scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses. RESULTS: The final multiple linear regression models indicated main effects for age on all scores, such that scores increased linearly as a function of age. Age2 had a significant effect in all countries except Cuba, and Puerto Rico for free recall score; a significant effect for memory delay score in all countries except Cuba and Puerto Rico; and a significant effect for recognition score in in all countries except Guatemala, Honduras, and Puerto Rico. Models showed an effect for MLPE in Chile (free recall), Honduras (free recall), Mexico (free recall), Puerto Rico (free recall, memory delay, and recognition), and Spain (free recall and memory delay). Sex affected free recall score for Cuba, Ecuador, Guatemala, Mexico, Paraguay, Peru, and Spain, memory delay score for all countries except Chile, Paraguay, and Puerto Rico, and recognition score for Ecuador, Mexico, Peru, and Spain, with girls scoring higher than boys. CONCLUSIONS: This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate way to interpret the TAMV-I with pediatric populations

    Concentration Endurance Test (d2): Normative data for Spanish-speaking pediatric population

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    OBJECTIVE: To generate normative data for the Concentration Endurance Test (d2) in Spanish-speaking pediatric populations. METHOD: The sample consisted of 4,373 healthy children from nine countries in Latin America (Chile, Cuba, Ecuador, Guatemala, Honduras, Mexico, Paraguay, Peru, and Puerto Rico) and Spain. Each participant was administered the d2 test as part of a larger neuropsychological battery. The Total number of items processed (TN), Total number of correct responses (CR), Total performance (TP), and Concentration performance (CP) scores were normed using multiple linear regressions and standard deviations of residual values. Age, age2, sex, and mean level of parental education (MLPE) were included as predictors in the analyses. RESULTS: The final multiple linear regression models showed main effects for age on all scores, such that scores increased linearly as a function of age. TN scores were affected by age2 for Guatemala and Puerto Rico; CR scores were affected by age2 for Mexico; TP scores were affected by age2 for Chile, Mexico, Puerto Rico, and Spain; and CP scores for Mexico and Spain. Models indicated that children whose parents had a MLPE >12 years obtained higher scores compared to children whose parents had a MLPE≀12 years for Mexico and Spain in all scores, and Puerto Rico for TN, CR, and TP, and Guatemala and Paraguay for CP scores. Sex affect the scores for Ecuador and Honduras (CP scores). CONCLUSIONS: This is the largest Spanish-speaking pediatric normative study in the world, and it will allow neuropsychologists from these countries to have a more accurate approach to interpret the d2 test in pediatric populations
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