162 research outputs found

    Promoting entrepreneurial potential in adolescents: A pilot study based on intergenerational contact

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    Recently there has been an increasing interest in promoting entrepreneurship among undergraduates, however, there have been few studies focusing on adolescents. The two aims of this research were to demonstrate the reliability and validity of the Attitudes to Entrepreneurship (ATE) test with a sample of Spanish adolescents, and to study the effect of using an intervention based on intergenerational contact on the entrepreneurial potential of young people. Two studies were carried out with these objectives. The results from Study 1 confirmed the reliability of the ATE test; entrepreneurial potential was related to achievement motivation and affected by gender. In Study 2, we used an experimental and control groups design and pre and post-test measures. In the classroom context, older adults were interviewed by students about their life and work experiences. Entrepreneurship was increased by the intergenerational contact in the experimental group, specifically, in the Leadership, Creativity and Achievement factors, in boys. Achievement motivation in the academic context also was increased. The intergenerational contact based on emotional implications and active participation promotes latent entrepreneurship and academic interest

    Nueva economía 20+20

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    276 p : il.El fuerte avance de las Tecnologías de la Información y las Comunicaciones (TIC) ha provocado profundos cambios económicos, sociales y culturales en las últimas décadas (Cohen, De Long y Zysman, 2000). La gran velocidad con la que se ha producido este cambio ha quedado reflejada en cifras, como el avance de Internet que, desde 1969, fecha de su nacimiento, hasta la actualidad, se ha extendido a más del 25% de la población mundial, con más de 1.700 millones de usuarios en todo el mundo, siendo especialmente significativos los casos de Europa y Estados Unidos, con penetraciones del 52% y 74,2%, respectivamente (Internet World Stats, 2009). Es igualmente significativo el fuerte crecimiento experimentado por los ordenadores personales que, desde 1977, año en el que vio la luz el primero de ellos, se estima que alcanzaron los 1.000 millones en el 2008, y se hacen predicciones de que se doblará dicha cifra en torno al año 2014 (Gartner, 2008). El trabajo, el ocio, el transporte o, incluso, las relaciones personales se encuentran en un proceso de cambio permanente debido a la profunda influencia que estas tecnologías han tenido sobre la sociedad. Tanto es así que en la nueva realidad, a la que el conocimiento y la tecnología trasladan al ser humano, existen nuevas concepciones del tiempo o del espacio (Castells, 2005). Desde el punto de vista económico, se han producido cambios en la estructura mundial que han desembocado en una nueva economía. Por una parte, las nuevas tecnologías han transformado la economía tradicional, dando lugar a una compleja estructura interconectada de forma global, en la que el desarrollo de las comunicaciones ha jugado un papel fundamental. Adicionalmente, la incorporación de la tecnología en el proceso productivo ha transformado elementos tales como la localización, el tamaño, las estructuras o las relaciones entre las empresas (Brynjolfsson y Kahln, 2000). Por otra parte, las nuevas tecnologías dan lugar a un nuevo mercado de enormes dimensiones, formado por todos aquellos bienes y servicios que dependen de forma crítica de las tecnologías digitales o lo son en sí mismas, lo cual constituye la base de la economía digital (Kling y Lamb, 1999). Con todo ello, el presente informe se encarga, en primer lugar, de identificar en qué consiste la economía digital y cuáles son sus principales componentes. En el siguiente apartado se intenta medir la importancia de este sector, a través de los datos más significativos, que reflejan el crecimiento que dicho sector de la economía ha sufrido en los últimos años, y la importancia relativa del mismo respecto al resto de los sectores. A continuación se presenta una caracterización de los perfiles de empresa que constituyen la economía digital y se busca plantear, después, un modelo de variables significativas que nos permita medir de forma adecuada el sector.Esta publicación ha contado con la cofinancia- ción del Fondo Social Europeo a través del Pro- grama Operativo Plurirregional de Adaptabili- dad y Empleo 2007-2013.ÍNDICE Capítulo 0 EL PROYECTO SECTORES DE LA NUEVA ECONOMÍA 20+20 Capítulo 1 LA ECONOMÍA DIGITAL 1 Introducción 2 ¿Qué es la economía digital? 3 Importancia de la economía digital 4 Las empresas de la economía digital 5 ¿Cómo analizar la economía digital? 6 Conclusiones Capítulo 2 EXPERIENCIAS EMPRESARIALES 11870.COM AGNITIO ASPgems BARRABESBIZ BITDEFENDER BUONGIORNO BUYVIP COMEX GRUPO IBÉRICA DAEDALUS DEIMOS SPACE EPTISA TI ÍNCIPY ISDE ING KERAJET LA CIGÜEÑA DEL BEBÉ MICROGÉNESIS QAPACITY ÍNDICE TERRITORIO CREATIVO TOPRURAL TYVEN Capítulo 3 CONCLUSIONES Capítulo 4 BIBLIOGRAFÍ

    Upper and lower spinal cord blood supply : the continuity of the anterior spinal artery and the relevance of the lumbar arteries

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    Objective: Thoracic and thoracoabdominal aortic repair are still complicated by spinal cord ischemia and paraplegia. The aim of the present article is to present the results of an anatomical study conducted by means of both postmortem injection of the vertebral artery and perfusion of the abdominal aorta. Methods: The spinal cord blood supply was investigated in 51 Caucasian cadavers: in 40 cases a methylene blue solution was hand-injected into the vertebral artery, whereas in the remaining 11 cases the abdominal aorta was perfused with a methylene blue solution by means of a roller pump. The level and side of the arteria radicularis magna and the continuity of the anterior spinal artery were recorded. Results: The anterior spinal artery was a continuous vessel without interruptions along the spinal cord in all 51 cases. The arteria radicularis magna level was variable, ranging from T9 to L5. The arteria radicularis magna arose from a lumbar artery in 36 cases (70.5%) and it was left-sided in 32 cases (62.7%). Conclusions: The anterior spinal artery constitutes an uninterrupted pathway between the vertebral arteries, the arteria radicularis magna, and the posterior intercostal and lumbar arteries. Moreover, the arteria radicularis magna arises from a lumbar artery in most of cases. Therefore, the sacrifice of the intercostal arteries during a thoracic aorta repair could be justified, at least from an anatomical standpoint. However, if an extended thoracoabdominal aortic repair is planned, it may be prudent to preserve the blood flow from the lumbar arteries

    Large scale stochastic inventory routing problems with split delivery and service level constraints

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    A stochastic inventory routing problem (SIRP) is typically the combination of stochastic inventory control problems and NP-hard vehicle routing problems, which determines delivery volumes to the customers that the depot serves in each period, and vehicle routes to deliver the volumes. This paper aims to solve a large scale multi-period SIRP with split delivery (SIRPSD) where a customer’s delivery in each period can be split and satisfied by multiple vehicle routes if necessary. This paper considers SIRPSD under the multi-criteria of the total inventory and transportation costs, and the service levels of customers. The total inventory and transportation cost is considered as the objective of the problem to minimize, while the service levels of the warehouses and the customers are satisfied by some imposed constraints and can be adjusted according to practical requests. In order to tackle the SIRPSD with notorious computational complexity, we first propose an approximate model, which significantly reduces the number of decision variables compared to its corresponding exact model. We then develop a hybrid approach that combines the linearization of nonlinear constraints, the decomposition of the model into sub-models with Lagrangian relaxation, and a partial linearization approach for a sub model. A near optimal solution of the model found by the approach is used to construct a near optimal solution of the SIRPSD. Randomly generated instances of the problem with up to 200 customers and 5 periods and about 400 thousands decision variables where half of them are integer are examined by numerical experiments. Our approach can obtain high quality near optimal solutions within a reasonable amount of computation time on an ordinary PC

    Why Reform Fails : The ‘Politics of Policies’ in Costa Rican Telecommunications Liberalization

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    As the \u27Washington Consensus\u27 reforms are losing momentum in Latin America, the Inter- American Development Bank (IDB) is calling for shifting the focus from the content of policy choices to the political process of their implementation. As this paper studies the paradigmatic case of telecommunications reform in Costa Rica it underscores the importance of these \u27politics of policies\u27. The analysis finds, however, that the failure of repeated liberalization initiatives was not only due to policy-makers\u27 errors in steering the project through \u27the messy world of politics\u27 (IDB); instead, as liberalization remained unpopular, policy content indeed mattered, and only the interaction of both explains the outcome. Particular attention is drawn to the political feed-back effects, as the failed reform, precisely because it had been backed by bi-partisan support, became a catalyst for the disintegration of the country\u27s long-standing two-party system.In dem Maße, in dem die mit dem „Washington Consensus“ verbundenen Reformen in Lateinamerika ins Stocken geraten sind, plädiert die Inter-American Development Bank (IDB) für eine stärkere Berücksichtigung nicht nur der Politikinhalte (policies), sondern auch des politischen Prozesses von deren Umsetzung (politics). Die vorliegende Untersuchung zum paradigmatischen Fall der Reform des Telekommunikationssektors in Costa Rica unterstreicht die Bedeutung dieser „politics of policies“. Sie zeigt allerdings auch, dass Ursache für das Scheiten wiederholter Liberalisierungsinitiativen nicht nur Fehler der Politiker sind, das Vorhaben durch „die unordentliche Welt der politics“ (IDB) zu steuern. Die breite gesellschaftliche Opposition gegen den Liberalisierungskurs bleibt. Nur die Interaktion von beiden, politics und policies, erklärt Verlauf und Ergebnis der Reform. Besonderes Augenmerk widmet die Studie den politischen Rückwirkungen der gescheiterten Reform: Sie wurde, just weil sie von beiden etablierten Parteien unterstützt wurde, zum Katalysator für den Zerfall des seit Jahrzehnten etablierten Zweiparteiensystems des Landes

    Synthesis of Structurally Related Coumarin Derivatives as Antiproliferative Agents

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    A library of structurally related coumarins was generated through synthesis reactions and chemical modification reactions to obtain derivatives with antiproliferative activity both in vivo and in vitro. Out of a total of 35 structurally related coumarin derivatives, seven of them showed inhibitory activity in in vitro tests against Taq DNA polymerase with IC50 values lower than 250 μM. The derivatives 4-(chloromethyl)-5,7-dihydroxy-2H-chromen-2-one (2d) and 4-((acetylthio)methyl)-2-oxo-2H-chromen-7-yl acetate (3c) showed the most promising anti-polymerase activity with IC50 values of 20.7 ± 2.10 and 48.25 ± 1.20 μM, respectively. Assays with tumor cell lines (HEK 293 and HCT-116) were carried out, and the derivative 4-(chloromethyl)-7,8-dihydroxy-2H-chromen-2-one (2c) was the most promising, with an IC50 value of 8.47 μM and a selectivity index of 1.87. In addition, the derivatives were evaluated against Saccharomyces cerevisiae strains that report about common modes of actions, including DNA damage, that are expected for agents that cause replicative stress. The coumarin derivatives 7-(2-(oxiran-2-yl)ethoxy)-2H-chromen-2-one (5b) and 7-(3-(oxiran-2-yl)propoxy)-2H-chromen-2-one (5c) caused DNA damage in S. cerevisiae. The O-alkenylepoxy group stands out as that with the most important functionality within this family of 35 derivatives, presenting a very good profile as an antiproliferative scaffold. Finally, the in vitro antiretroviral capacity was tested through RT-PCR assays. Derivative 5c showed inhibitory activity below 150 μM with an IC50 value of 134.22 ± 2.37 μM, highlighting the O-butylepoxy group as the functionalization responsible for the activity.This research was supported by CONICET (PIP 11220200101091CO 2021-2023), PICT 2017-0785 Type D of the National Agency for Scientific and Technological Promotion, UNSL (PROICO 02-2620), and RGLP from AvH Foundation. E.F.B.-H. thanks CONICET for doctoral fellowship and specially to Graphic Designer Bruna-Haupt L. for his help. H.A.G. thanks CONICET for belonging to the CIC. We wish thank to Dr. Di Marco N. I. for the genetic material gently provided. C.R.P. thanks CONICET for belonging to the CIC and Alexander von Humboldt Foundation for the different subsidies. We appreciate language revision by staff from the Instituto de Lenguas, UNSL, and specially Mg. Rezzano S.F.M. thanks to the Spanish Ministry of Science (research grant BFU2017-83954-R), ACIISI (research grant ProID2017010167), and FIISC (research grant PIFIIS19/04). C.G. thanks Ministerio de Ciencia, Innovación y Universidades (MCIU) of Spain-European Regional Development Fund (ERDF) (PGC2018-094503-B-C22). This work is a part of the cotutelled (UNSL-ULL) Ph.D. of E.F.B.-H.Peer reviewe

    Lagrangian relaxation bounds for a production-inventory-routing problem

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    We consider a single item Production-Inventory-Routing problem with a single producer/supplier and multiple retailers. Inventory management constraints are considered both at the producer and at the retailers, following a vendor managed inventory approach, where the supplier monitors the inventory at retailers and decides on the replenishment policy for each retailer. We assume a constant production capacity. Based on the mathematical formulation we discuss a classical Lagrangian relaxation which allows to decompose the problem into four subproblems, and a new Lagrangian decomposition which decomposes the problem into just a production-inventory subproblem and a routing subproblem. The new decomposition is enhanced with valid inequalities. A computational study is reported to compare the bounds from the two approaches

    Invited perspectives: A research agenda towards disaster risk management pathways in multi-(hazard-)risk assessment

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    Whilst the last decades have seen a clear shift in emphasis from managing natural hazards to managing risk, the majority of natural-hazard risk research still focuses on single hazards. Internationally, there are calls for more attention for multi-hazards and multi-risks. Within the European Union (EU), the concepts of multi-hazard and multi-risk assessment and management have taken centre stage in recent years. In this perspective paper, we outline several key developments in multi-(hazard-)risk research in the last decade, with a particular focus on the EU. We present challenges for multi-(hazard-)risk management as outlined in several research projects and papers. We then present a research agenda for addressing these challenges. We argue for an approach that addresses multi-(hazard-)risk management through the lens of sustainability challenges that cut across sectors, regions, and hazards. In this approach, the starting point is a specific sustainability challenge, rather than an individual hazard or sector, and trade-offs and synergies are examined across sectors, regions, and hazards. We argue for in-depth case studies in which various approaches for multi-(hazard-)risk management are co-developed and tested in practice. Finally, we present a new pan-European research project in which our proposed research agenda will be implemented, with the goal of enabling stakeholders to develop forward-looking disaster risk management pathways that assess trade-offs and synergies of various strategies across sectors, hazards, and spatial scales
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