Self-Selection Patterns among Return Migrants: Mexico 1990-2010

This paper analyzes the self-selection patterns among Mexican return migrants during the period from 1990 to 2010. Using census data, we can identify return migrants who have lived in the United States within the previous 5 years but who currently live in Mexico. To calculate the selection patterns, we non parametrically estimate the counterfactual wages that the return migrants would have experienced had they never migrated by using the wage structure of non migrants. We find evidence that the selection patterns change over time toward negative selection. For example, in 1990, the wages that the male return migrants would have experienced had they not migrated was 6 percent larger than the wages of male non migrants. However, by 2010, the difference had declined to -14 percent. The increasing negativity of the degree of selection is robust to the analysis of specific subgroups: rural and urban, men and women, and states with high migration rates and low migration rates. Moreover, the negative selection results for the period from 2000 to 2010 are robust to the use of different surveys that define a return migrant by using distinct characteristics. Additionally, we observe that the wages of return migrants are larger than those that the migrants would have obtained had they not migrated. This finding shows that migration has a positive effect on the Mexican economy.Mexican migration, self-selection, return migration, wages

Development of a Maintenance System Based on Web and Mobile Technologies

The paper reports the development of an e-monitoring and maintenance system based on web technology and mobile device, PDA. Rarity of experts led to the application of artificial intelligence and later, distributed artificial intelligence for condition monitoring and diagnosis of machine condition. Recently, web technology along with wireless communication is emerging as a potent tool in maintenance. It facilitates obtaining of the desired information by the relevant personnel at any time wherever he may be. The paper first describes the web and mobile architecture that formed the basis of the system and ICT tools used to communicate among the different layers in the architecture/system and its various client machines. It is followed by the demonstration of the use of the system with a faulty bearing simulated signal. A mobile emulator was used to perf ect the system for different requirements and the same was then tested on the PDA

IMS signalling for multiparty services based on network level multicast

3rd EURO-NGI Conference on Next Generation Internet Networks. Norwegian University of Science and Technology, Trondheim, Norway, 21-23 may 2007.The standardization process of the UMTS technology has led to the development of the IP Multimedia Subsystem (IMS). IMS provides a framework that supports the negotiation of the next generation multimedia services with QoS requirements that are envisioned for 3G networks. But even though many of these services involve the participation of multiple users in a multiparty arrangement, the delivery technology at network level is still unicast based. This approach is not optimum, in terms of transmission efficiency. In this paper, a new approach is presented proposing to use a network level multicast delivery technology for the multiparty services that are signalled through IMS. The main advantages and drawbacks related with this new approach are analyzed in the article. Finally, as a starting point in the development of the presented solution, a new SIP signalling dialogue is proposed allowing the negotiation of a generic multiparty service, and supporting at the same time the configuration of the corresponding network level multicast delivery service with QoS requirements that will be used in the user plane.Publicad

Provenance does matter: links between winter trophic segregation and the migratory origins of European robins

Amongst migratory species, it is common to find individuals from different populations or geographical origins sharing staging or wintering areas. Given their differing life histories, ecological theory would predict that the different groups of individuals should exhibit some level of niche segregation. This has rarely been investigated because of the difficulty in assigning migrating individuals to breeding areas. Here, we start by documenting a broad geographical gradient of hydrogen isotopes (δ2H) in robin Erithacus rubecula feathers across Europe. We then use δ2H, as well as wing-tip shape, as surrogates for broad migratory origin of birds wintering in Iberia, to investigate the ecological segregation of populations. Wintering robins of different sexes, ages and body sizes are known to segregate between habitats in Iberia. This has been attributed to the despotic exclusion of inferior competitors from the best patches by dominant individuals. We find no segregation between habitats in relation to δ2H in feathers, or to wing-tip shape, which suggests that no major asymmetries in competitive ability exist between migrant robins of different origins. Trophic level (inferred from nitrogen isotopes in blood) correlated both with δ2H in feathers and with wing-tip shape, showing that individuals from different geographic origins display a degree of ecological segregation in shared winter quarters. Isotopic mixing models indicate that wintering birds originating from more northerly populations consume more invertebrates. Our multi-scale study suggests that trophic-niche segregation may result from specializations (arising in the population-specific breeding areas) that are transported by the migrants into the shared wintering grounds

Blockchain Technology Helps Maintenance to Stop Climate Change

The development and interest in Industry 4.0 together with rapid development of Cyber Physical Systems has created magnificent opportunities to develop maintenance to a totally new level. The Maintenance 4.0 vision considers massive exploitation of information regarding factories and machines to improve maintenance efficiency and efficacy, for example by facilitating logistics of spare parts, but on the other hand this creates other logistics issues on the data itself, which only exacerbate data management issues that emerge when distributed maintenance platforms scale up. In fact, factories can be delocalized with respect to the data centers, where data has to be transferred to be processed. Moreover, any transaction needs communication, be it related to purchase of spare parts, sales contract, and decisions making in general, and it has to be verified by remote parties. Keeping in mind the current average level of Overall Equipment Efficiency (50%) i.e. there is a hidden factory behind every factory, the potential is huge. It is expected that most of this potential can be realised based on the use of the above named technologies, and relying on a new approach called blockchain technology, the latter aimed at facilitating data and transactions management. Blockchain supports logistics by a distributed ledger to record transactions in a verifiable and permanent way, thus removing the need for multiple remote parties to verify and store every transaction made, in agreement with the first “r” of maintenance (reduce, repair, reuse, recycle). Keeping in mind the total industrial influence on the climate change, we can expect that with the aid of the new advancements the climate change can be if not totally stopped at least reduced, and contribute to the green economy that Europe aims for. The paper introduces the novel technologies that can support sustainability of manufacturing and industry at large, and proposes an architecture to bind together said technologies to realise the vision of Maintenance 4.0.info:eu-repo/semantics/publishedVersio

Crisis económica: ¿fin del intervencionismo estatal?

La intervención económica del Estado, doctrina y mandato de la Constitución Política de los Estados Unidos Mexicanos y cuya existencia tiene profunda raíz revolucionaria popular, es un claro resultado de la ideología de la liberación que, por mucho tiempo alentó la modernización económica de México. Desde hace cincuenta y cinco años, las empresas públicas mexicanas denotan que la decisión de crearlas, conservarlas o, en su caso, de que el sector privado pueda adquirirlas o absorberlas, responde a momentos y exigencias específicas del desarrollo nacional. En general, la creación, adquisición o absorción y conservación de las entidades paraestatales en toda la diversidad de la estructura económica, brindó al gobierno mexicano la oportunidad de tomar los mandos o, al menos, ejercer la orientación general de la economía en conjunto, mediante la generación de insumos, de productos de uso final y de servicios, lo que también le permitió realizar profundas transformaciones no solo económicas, sino sociales, y con ello incluso se condicionó la vida política. Esas transformaciones, sin embargo, no siempre tuvieron un signo positivo, vistas las cosas desde el ángulo de una construcción nacional sólida y duradera, pues a su sombra prosperaron también innegables vicios económicos, sociales y políticos, algunos de los cuales fueron de simple comportamiento gubernamental, frente al conjunto social de la Nacion, y otros entraron de lleno en toda la extensión y profundidad de su estructura

Exactitud en la medición de edad dental mediante el método de Nolla versus métodos de Demirjian, en pacientes de 6 a 17 años evaluados en el Programa de Especialización de Ortodoncia y Ortopedia Dentofacial de la Universidad de Talca entre 2005 y 2009

78 p.Esta investigación tiene como objetivo determinar cuál es el método de estimación de edad dental más exacto para determinar edad cronológica, para esto se compara el método de Nolla versus el de Demirjian. Se aplicaron ambos métodos en una muestra total de 108 ortopantomografías de pacientes diagnosticados en el Programa de Especialización en Ortopedia y Ortodoncia Dentofacial de la Universidad de Talca, entre los años 2005 al 2009, cuyas edades fluctúan entre los 6 y 17 años. Para una manipulación más sencilla se digitalizó los registros radiográficos, los que fueron analizados de forma individual por la memorista, previamente calibrada. Determinada la edad dental mediante el método de Nolla y el método de Demirjian, los resultados se sometieron a análisis estadísticos. Se determinó que existe una correlación entre edad cronológica y edad dental diagnosticada por el método de Nolla y también mediante el método de Demirjian. La edad dental obtenida mediante el primer método mencionado (Nolla) subestima edad cronológica, mientras que la edad dental obtenida a partir del segundo método (Demirjian) la sobrestima. Se concluyó que la diferencia entre la edad cronológica y la edad dental es menor cuando se obtiene edad dental diagnosticada por el método de Demirjian, siendo este por lo tanto, el más exacto para determinar edad cronológica, tanto en pacientes de sexo masculinos y femeninos de la muestra. Palabras claves: edad cronológica, edad dental, método de Nolla, método de Demirjian, Ortopantomografía

MOTIVACIÓN Y SU INFLUENCIA EN EL CLIMA ORGANIZACIONAL EN LOS DOCENTES DE LA INSTITUCIÓN EDUCATIVA EMBLEMATICA “SAN JOSÉ” – CHICLAYO, 2013

El presente trabajo de investigación de naturaleza cuantitativa, con diseño descriptivo correlacional, con el objetivo de determinar la relación existente entre la  motivación y el Clima Organizacional en los Docentes de la Institución Educativa Emblemática “San José” de Chiclayo. La muestra estuvo constituida por cuarentaicuatro profesores. Se utilizó como instrumento la Escala de Motivación de Steers y Braunstein y el Cuestionario del Clima Organizacional. Los resultados muestran que los niveles de motivación tienden a niveles medios (47.7%), además, entre los factores del clima organizacional: los docentes consideran que hay niveles medios de comunicación (59.1%); en el factor liderazgo presentan niveles medios (45.5%) y bajos (25%) indicando que no hay un ejercicio activo de liderazgo, en cuanto al clima organizacional general,  tiene prevalencia a niveles medianamente favorables (50%). Finalmente, las pruebas de correlación C de Pearson (0.675), indican que existe una influencia significativa entre los niveles de motivación y clima organizacional