161 research outputs found
Mercados protegidos y consumo desigual. Cuba y el capitalismo español entre 1878 y 1898
Editada en la Fundación Empresa PúblicaEn el presente artículo se examina la evolución del intercambio comercial entre España y Cuba en el periodo de 1878 a 1898, las variaciones en el volumen y composición de las transacciones, así como su incidencia en el conjunto de las economías española y cubana, revisándose el impacto de las exportaciones peninsulares sobre el mercado colonial. Las conclusiones apuntan una sobrevaloración instrumental de la dominación mercantil antillana destinada a obtener ventajas en la política comercial española que, sin embargo, contribuyó a fomentar una conciencia de dependencia en vísperas de la guerra de emancipación.This article examines the evolution of trade exchange between Spain and Cuba from 1878 to 1898, the variations in the volume and composition of the transactions and their effect on Spanish and Cuban economies as a whole, reviewing the impact of peninsular exports on the colonial market. The conclusions point to an instrumental overvaluation of Antillas' mercantile domination aiming to obtain advantages in Spain's commercial policy, which nevertheless helped to foster an awareness of dependence on the eve of the war of independence.Publicad
Experiential Avoidance and Technological Addictions in Adolescents
Background and aims This study focuses on the use of popular information and communication technologies (ICTs) by adolescents: the Internet, mobile phones, and video games. The relationship of ICT use and experiential avoidance (EA), a construct that has emerged as underlying and transdiagnostic to a wide variety of psychological problems, including behavioral addictions, is examined. EA refers to a self-regulatory strategy involving efforts to control or escape from negative stimuli such as thoughts, feelings, or sensations that generate strong distress. This strategy, which may be adaptive in the short term, is problematic if it becomes an inflexible pattern. Thus, the aim of this study was to explore whether EA patterns were associated with addictive or problematic use of ICT in adolescents. Methods A total of 317 students of the Spanish southeast between 12 and 18 years old were recruited to complete a questionnaire that included questions about general use of each ICTs, an experiential avoidance questionnaire, a brief inventory of the Big Five personality traits, and specific questionnaires on problematic use of the Internet, mobile phones, and video games. Results Correlation analysis and linear regression showed that EA largely explained results regarding the addictive use of the Internet, mobile phones, and video games, but not in the same way. As regards gender, boys showed a more problematic use of video games than girls. Concerning personality factors, conscientiousness was related to all addictive behaviors. Discussion and conclusions We conclude that EA is an important construct that should be considered in future models that attempt to explain addictive behaviors
Capitales en el azúcar. Los hacendados cubanos ante la rentabilidad económica y la oportunidad de inversión (1878-1895)
This article studies the great hacienda-owners and, in particular, the strategies they applied in order to diversify their income through investment in sugar and other alternative activities, both in and outside Cuba. Investments on these alternative sectors stemmed form return estimations rather than from lack of financial resources.Estudio de los grandes hacendados y en particular de las estrategias de diversificación que utilizaron a la hora de invertir en el azúcar y en otras actividades alternativas en Cuba y en el exterior. Las inversiones en cada uno de estos sectores y actividades guardó más relación con un cálculo de rendimientos que con la falta de recursos financieros
Presentación
Not available.El actual número de Revista de Indias selecciona un número de temas que tienen como eje la renovación y conservación de la esclavitud entre finales del XVIII y comienzos del XIX, las resistencias y vías de emancipación dentro del sistema, las condiciones demográficas y de producción que subsisten en una coyuntura distinta a la del esplendor de la economía esclavista, que antecede y anuncia la abolición. En sus páginas, de una u otra forma, están presentes a cada momento las políticas de la esclavitud, menos como disposiciones legales y orientaciones de gobierno como en su construcción cotidiana a través de una combinación de normas jurídicas, prácticas sociales y reclamos materiales. Los artículos aquí reunidos ofrecen distintas perspectivas metodológicas sobre temas que apuntan a la convergencia de la trayectoria histórica de la esclavitud negra en Brasil y en Cuba. Con este volumen esperamos estimular a los investigadores que se ocupan de esos dos espacios a integrar, en un cuadro de análisis unificado, el examen de los dos últimos imperios esclavistas de Occidente. Es una tarea que, ciertamente, corresponderá antes a esfuerzos colectivos que a iniciativas aisladas de investigación
Phenomenological methodology for assessing the influence of flow conditions on the acoustic response of exhaust aftertreatment systems
[EN] The increasing limits of standards on aerosol and gaseous emissions from internal combustion engines have led to the progressive inclusion of different exhaust aftertreatment systems (EATS) as a part of the powertrain. Regulated emissions are generally abated making use of devices based on monolithic structures with different chemical functions. As a side effect, wave transmission across the device is affected and so is the boundary at the exhaust line inlet, so that the design of the latter is in turn affected. While some models are available for the prediction of these effects, the geometrical complexity of many devices makes still necessary in many cases to rely on experimental measurements, which cannot cover all the diversity of flow conditions under which these devices operate.
To overcome this limitation, a phenomenological methodology is proposed in this work that allows for the sound extrapolation of experimental results to flow conditions different from those used in the measurements. The transfer matrix is obtained from tests in an impulse rig for different excitation amplitudes and mean flows. The experimental coefficients of the transmission matrix of the device are fitted to Fourier series. It allows treating the influence of the flow conditions on the acoustic response, which is manifested on changes in the characteristic periods, separately from the specific properties of every device. In order to provide predictive capabilities to the method, the Fourier series approach is coupled to a gas dynamics model able to account for the sensitivity of propagation velocity to variations in the flow conditions. (C) 2017 Elsevier Ltd. All rights reserved.This work has been partially supported by the Spanish Ministerio de Economia y Competitividad through Grant no. TRA2013-40853-R. Additionally, the Ph.D. student E.J. Sanchis has been funded by a grant from Universitat Politecnica de Valencia with reference FPI-2016-S2-1355. These supports are gratefully acknowledged by the authors. Finally, the authors wish also to acknowledge the suggestions of the referees, which have resulted in a considerable improvement of the text.Torregrosa, AJ.; Arnau Martínez, FJ.; Piqueras, P.; Sanchis-Pacheco, EJ.; Tartoussi, H. (2017). Phenomenological methodology for assessing the influence of flow conditions on the acoustic response of exhaust aftertreatment systems. Journal of Sound and Vibration. 396:289-306. https://doi.org/10.1016/j.jsv.2017.02.03328930639
Assessment of acoustic reciprocity and conservativeness in exhaust aftertreatment systems
[EN] Tightening emission standards limiting gas and aerosol emissions from internal combustion engines have led to the extensive use of exhaust aftertreatment systems (EATS) with different chemical functions as a solution to meet standards requirements. Incidentally, the placement of aftertreatment monolithic devices into the exhaust line also plays a key role on the exhaust noise emission. Their presence disturbs the pattern of the pressure waves and sets the boundary conditions for the silencer design. The impact of the EATS on wave transmission can be analyzed by means of the transmission or scattering matrix. The present work discusses the implications of acoustic reciprocity and conservativeness on the definition of the scattering matrix elements. The fulfillment of these properties in real operating conditions was evaluated against a set of experimental data obtained for several exhaust aftertreatment monolithic bricks in an impulse test rig. The influence of different excitation amplitudes and superimposed mean flows was also considered. Once it was shown that the devices are reciprocal, the need to account for dissipation phenomena was evidenced. Finally, the application of reciprocity and conservativeness together with dissipation provided simple expressions allowing to predict the response of the EATS in the inverse direction, i.e. from outlet to inlet, from the transmission and reflection properties obtained in the direct direction. Thus, the proposed procedure becomes useful to reduce both the required number of tests and the gas dynamics modelling work in methodologies driven to assess the acoustic response of EATS based on the use of experimental and computational tools. (C) 2018 Elsevier Ltd. All rights reserved.This research has been partially supported by FEDER and the Government of Spain through project TRA2016-79185-R. Additionally, the Ph.D. student Enrique José Sanchis has been funded by a grant from Universitat Politècnica de València with reference FPI-2016-S2-1355.Torregrosa, AJ.; Piqueras, P.; Sanchis-Pacheco, EJ.; Guilain, S.; Dubarry, M. (2018). Assessment of acoustic reciprocity and conservativeness in exhaust aftertreatment systems. Journal of Sound and Vibration. 436:46-61. https://doi.org/10.1016/j.jsv.2018.08.032S466143
The Glial Cell of Human Cutaneous Sensory Corpuscles: Origin, Characterization, and Putative Roles
Sensory corpuscles of human skin are structures located at the peripheral end of the mechanoreceptive neurons and function as low-threshold mechanoreceptors (LTMRs). In its structure, in addition to the axon, there are glial cells, not myelinating, that are organized in different ways according to the morphotype of sensitive corpuscle, forming the so-called laminar cells of Meissner’s corpuscles, the laminar cells of the inner core of Pacinian corpuscles, or cells of the inner core in Ruffini’s corpuscles. Classically the glial cells of sensory corpuscles have been considered support cells and passive in the process of mechanotransduction. However, the presence of ion channels and synapses-like systems between them and the axon suggests that corpuscular glial cells are actively involved in the transformation of mechanical into electrical impulses. This chapter is an update on the origin, development, cytoarchitecture, and protein profile of glial cells of sensitive corpuscles especially those of human glabrous skin
Assessing Emotional Distress in Adolescents: Psychometrics of the Spanish Version of the Social Emotional Distress Scale-Secondary
Background
The Social Emotional Distress Scale-Secondary (SEDS-S) is a short measure designed for comprehensive school-based mental health screening, particularly for using very brief self-reported measures of well-being and distress. Whereas prior studies have shown validity and reliability evidence for the English version, there is a lack of literature about its psychometric properties for Spanish-speaking youths.
Objective
To examine the psychometric properties of the SEDS-S in a large sample of Spanish adolescents, providing evidence of its reliability, structure, convergent and discriminant validity, longitudinal and gender measurement invariance, and normative data.
Methods
Participants were 5550 adolescents aged 12–18 years old. Test–retest reliability was examined using Cronbach’s alpha and McDonald’s omega coefficients, and evidence for convergent and discriminant validity was measured using Pearson’s correlation. Confirmatory factor analysis (CFA) was used to examine structure validity, while multigroup and longitudinal measurement invariance analysis was conducted for longitudinal and gender latent structure stability.
Results
The CFA supported a unidimensional latent structure, which was also observed to be invariant between gender groups and over time. The scale showed evidence of reliability, with coefficients above .85. In addition, the SEDS-S score was positively related to measures assessing distress and negatively related to measures assessing well-being, thereby providing convergent/discriminant validity of the total scores.
Conclusion
This study provides the first evidence of the reliability and validity of the Spanish version of the SEDS-S for assessing emotional distress among adolescents, cross-sectionally and longitudinally. Furthermore, findings indicated that SEDS-S could be a suitable assessment tool for screening and program evaluation purposes at different contexts beyond the school setting
Ajuste psicosocial en cibervíctimas y ciberagresores en educación secundaria
The rise of cyberbullying among high school students and the importance of certain variables of psychological adjustment for the comprehension of this type of violent behavior both in bullies and in victims. This work aims to analyze the psychological profile of individuals involved in situations of cyberbullying, both victims and bullies. The adjustment variables analyzed were self-concept, perceived stress, loneliness, depressive symptomatology, social anxiety, life satisfaction, and emotional intelligence. Using a sample of 1318 adolescents (47% boys), aged between 11 and 18 years (M = 13.8, SD = 1.32), three contrast groups were established for cybervictims (severe cybervictims, moderate cybervictims, and non-cybervictims) and three groups for cyberbullies (severe cyberbullies, moderate cyberbullies, and non-cyberbullies). The results obtained through analysis of variance showed that both cybervictims and cyberbullies show deterioration in most of the studied dimensions, albeit with a different profile. Severe cybervictims showed higher scores in perceived stress, loneliness, depression, and social anxiety, and lower scores in self-concept, life satisfaction, and emotional intelligence, in comparison with non-cybervictims. Severe cyberbullies obtained higher scores in perceived stress, loneliness, and depression, and lower scores in self-concept and life satisfaction, compared to non-cyberbullies. These results allow deepening our comprehension of cyberbullying among students to improve preventive and intervention programs in schools.El auge de las agresiones cibernéticas entre estudiantes de secundaria y la importancia de ciertas variables de ajuste psicosocial para la comprensión de este tipo de conducta violenta, tanto en agresores como en víctimas, plantean como objetivo en el presente trabajo analizar el perfil psicosocial de ambos implicados en situaciones de ciberagresión. Las variables de ajuste analizadas fueron autoconcepto, estrés percibido, soledad, sintomatología depresiva, ansiedad social, satisfacción con la vida e inteligencia emocional. A partir de una muestra de 1318 adolescentes (47% chicos), de entre 11 y 18 años, se establecieron tres grupos de contraste para cibervíctimas (víctimas severas, moderadas y no cibervíctimas) y tres grupos para ciberagresores (ciberagresores severos, moderados y no ciberagresores). El análisis de varianza mostró que los implicados presentan perfiles psicosociales diferentes y deteriorados. Las cibervíctimas severas mostraron mayor estrés percibido, soledad, depresión y ansiedad social, y menor autoconcepto, satisfacción con la vida e IE, en comparación con las no cibervíctimas. Los ciberagresores severos mostraron mayor estrés percibido, soledad y depresión, y menor autoconcepto y satisfacción con la vida, comparativamente con los no ciberagresores. Estos resultados permiten profundizar en la comprensión del ciberacoso entre estudiantes y mejorar los programas preventivos y de intervención en escuelas
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