Undocumented Migration to the United States A New Perspective

The history of economic development has demonstrated eloquently that developed countries, after a certain stage, begin to encounter manpower problems. The scarcity of manpower to work in occupations at the base of the labor pyramid deprives such countries of flexibility in their growth process. In every case, upon reaching this point--which for Germany and Switzerland, for example, was during the decade of the 70\u27s--countries have resorted to the importation of labor either through formal programs, as in the case of the European countries, or simply by allowing in one way or another the influx of illegal workers, as in the United States. From a purely economic point of view, immigration to a country leads to a per capita income increase across the board rather than simply an increase for the owners of capital, landowners, and groups that do not compete for manpower

Mexican migration to the United States : the view from rural sending communities

"June 1976.""#2118"--handwritten on coverIncludes bibliographical reference

The lemniscal–cuneate recurrent excitation is suppressed by strychnine and enhanced by GABAA antagonists in the anaesthetized cat

[Abstract] In the somatosensory system, cuneolemniscal (CL) cells fire high frequency doublets of spikes facilitating the transmission of sensory information to diencephalic target cells. We studied how lemniscal feedback affects ascending transmission of cutaneous neurons of the middle cuneate nucleus. Electrical stimulation of the contralateral medial lemniscus and of the skin at sites evoking responses with minimal threshold induced recurrent activation of CL cells at a latency of 1–3.5 ms. The lemniscal feedback activation was suppressed by increasing the stimulating intensity at the same sites, suggesting recurrent-mediated lateral inhibition. The glycine antagonist strychnine blocked the recurrent excitatory responses while GABAA antagonists uncovered those obscured by stronger stimulation. CL cells sharing a common receptive field (RF) potentiate one another by recurrent activation and disinhibition, the disinhibition being produced by serial interactions between glycinergic and GABAergic interneurons. Conversely, CL cells with different RFs inhibit each other through recurrent GABA-mediated inhibition. The lemniscal feedback would thus enhance the surround antagonism of a centre response by increasing the spatial resolution and the transmission of weak signals.Consejo Interinstitucional de Ciencia y Tecnología; PM99-002

A new view of Mexican migration to the United States

Thesis. 1980. Ph.D.--Massachusetts Institute of Technology. Dept. of Economics.MICROFICHE COPY AVAILABLE IN ARCHIVES AND DEWEY.Bibliography : leaves 178-192.by Juan Diez-Canedo.Ph.D

Artrodesis subastragalina artroscópica

Objetivo: evaluar la eficacia y complicaciones de la técnica artroscópica en la artrodesis subastragalina. Material y métodos: Durante los años 2007 y 2008 hemos realizado artrodesis subastragalina artroscópica por vía posterior a 12 pacientes, con una edad media de 41 años, por presentar artropatía postraumática de la articulación subastragalina, secundaria a fractura de calcáneo o astrágalo. El seguimiento medio ha sido de 9 meses. Resultados: Se ha conseguido la consolidación primaria de la artrodesis en 10 casos, evolucionando a seudoartrosis en los otros dos, que precisaron reintervención artroscópica con aporte de injerto óseo. En un caso ha existido migración proximal de un tornillo de osteosíntesis, no presentándose necrosis cutánea, infección ni afectación neurovascular en caso alguno. Conclusiones: Esta técnica se ha mostrado eficaz para la consecución de la artrodesis subastragalina, disminuyendo sensiblemente el porcentaje de complicaciones en relación con la cirugía abierta.Objective: To evaluate the effectiveness and complications of arthroscopic technique in subtalar arthrodesis. Methods: Between 2007 and 2008 we performed arthroscopic subtalar fusions with a posterior approach in 12 patients with a mean age of 41 years old, with a diagnose of posttraumatic subtalar arthropaty secondary to calcaneus or talus fractures. The mean follow-up was 9 months. Results:We obtained primary consolidation in 10 cases. Two cases developed non-union and required an arthroscopic revision with bone grafting. In one case there was proximal migration of a screw, with no skin necrosis, infection or neurovascular impairment in any case. Conclusions: This technique has been effective in order to obtain subtalar fusion, minimizing significantly the complications associated with open surgery

Parallel feature selection for distributed-memory clusters

Versión final aceptada de: https://doi.org/10.1016/j.ins.2019.01.050This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/ licenses/by-nc-nd/4.0/. This version of the article: González-Domínguez, J. et al. (2019) ‘Parallel feature selection for distributed-memory clusters’, has been accepted for publication in Information Sciences, 496, pp. 399–409. The Version of Record is available online at: https://doi.org/10.1016/j.ins.2019.01.050[Abstract]: Feature selection is nowadays an extremely important data mining stage in the field of machine learning due to the appearance of problems of high dimensionality. In the literature there are numerous feature selection methods, mRMR (minimum-Redundancy-Maximum-Relevance) being one of the most widely used. However, although it achieves good results in selecting relevant features, it is impractical for datasets with thousands of features. A possible solution to this limitation is the use of the fast-mRMR method, a greedy optimization of the mRMR algorithm that improves both scalability and efficiency. In this work we present fast-mRMR-MPI, a novel hybrid parallel implementation that uses MPI and OpenMP to accelerate feature selection on distributed-memory clusters. Our performance evaluation on two different systems using five representative input datasets shows that fast-mRMR-MPI is significantly faster than fast-mRMR while providing the same results. As an example, our tool needs less than one minute to select 200 features of a dataset with more than four million features and 16,000 samples on a cluster with 32 nodes (768 cores in total), while the sequential fast-mRMR required more than eight hours. Moreover, fast-mRMR-MPI distributes data so that it is able to exploit the memory available on different nodes of a cluster and then complete analyses that fail on a single node due to memory constraints. Our tool is publicly available at https://github.com/borjaf696/Fast-mRMR.This research has been partially funded by projects TIN2016-75845-P and TIN-2015-65069-C2-1-R of the Ministry of Economy, Industry and Competitiveness of Spain, as well as by Xunta de Galicia projects ED431D R2016/045 and GRC2014/035, all of them partially funded by FEDER funds of the European Union. We gratefully thank CESGA for providing access to the Finis Terrae II supercomputer.Xunta de Galicia; ED431D R2016/045Xunta de Galicia; GRC2014/03

Prótesis unicompartimental versus osteotomía tibial alta en la enfermedad degenerativa unicompartimental de rodilla

Se presenta un estudio comparativo prospectivo de 40 rodillas intervenidas quirúrgicamente por presentar afectación degenerativa de predominio del compartimento interno, 20 de ellas tratadas con una sustitución unicompartimental y las otras 20 con osteotomía tibial valguizante. El tiempo medio de seguimiento ha sido de 30 meses para el primer grupo y de 32 meses para el segundo. La valoración de resultados se realizó siguiendo los criterios del Hospital for Special Surgery, resultando en el grupo de las prótesis unicompartimentales un 50% excelentes y 50% buenos, frente a un 40% excelentes, 46,5% buenos y 13,5% regulares para el grupo de las osteotomías. Se concluye que hemos obtenido mejores resultados con las prótesis unicompartimentales, aunque cada caso debe ser valorado en particular para la aplicación de una u otra técnica.We present a prospective and comparative study of 40 knees operated because of degenerative pathology in the internal compartment, 20 knees were treated with unicompartmental replacement and the other with high tibial osteotomy. The average follow- up was 30 months in the first group and 32 months in the second. The Hospital for Special Surgery knee-rating score was used for preoperative and postoperative assessment, resulting 50% very good results and 50% good outcome in the unicompartmental replacement group, and 40% very good results, 46.5% good and 13.5% fair outcome in the tibial osteotomy group. The conclusion is that better results can be obtained with the unicompartmental arthroplasty, although each case must be evaluated individually to use one or another technique

Evaluación de los objetivos de desempeño sísmico alcanzados bajo los requerimientos de la guía boliviana de diseño sísmico 2020, en el diseño de edificaciones de hormigón armado para el departamento de Cochabamba, Bolivia: Avaliação dos objetivos de desempenho sísmico alcançados sob as exigências do guia de projeto sísmico boliviano 2020, no projeto de edifícios de concreto armado para o departamento de Cochabamba, Bolívia

La guía boliviana de diseño sísmico establece que las estructuras diseñadas bajo requerimientos de la misma en conjunto con la NB 1225001, alcanzaran un nivel de desempeño sísmico de seguridad de vida para sismos de diseño con periodos de retorno de 475 años. El objetivo principal del presente estudio es evaluar los objetivos de desempeño sísmico alcanzados, realizando el diseño sismorresistente de seis edificaciones para el departamento de Cochabamba a partir de sus planos arquitectónicos, utilizando lo estipulado en la Guía boliviana de diseño sísmico 2020, para posteriormente, realizar un análisis dinámico lineal Tiempo-Historia y así evaluar los niveles de desempeño sísmico globales. Asimismo, se realizó la evaluación de los niveles de desempeño sísmico locales mediante la aplicación del análisis estático no lineal pushover. Finalmente, tomando como referencia la matriz de desempeño propuesta por el Código Modelo de Diseño Sísmico para América Latina y el Caribe, se evaluaron los objetivos de desempeño sísmico alcanzados por las estructuras, emparejando los niveles de desempeño sísmico obtenidos con el nivel de movimiento sísmico utilizado, alcanzando objetivos de desempeño sísmico de Ocupación Inmediata

Nuestra experiencia con la enfermedad de Freiberg

Analizamos una serie de 34 pacientes, 9 varones y 25 mujeres, con enfermedad de Freiberg, detallando su localización y grado evolutivo en el momento del diagnóstico. Clínicamente la severidad del cuadro fue muy variable, y con frecuencia discordante con la imagen radiológica. Tan solo en 5 pacientes fue necesario el tratamiento quirúrgico. No se pudo detectar un factor etiológico claro y único, existiendo casos con y sin antecedentes traumáticos. Se describe la evolución radiológica de esta enfermedad. La RMN permite de forma precoz, detectar las anomalías óseas en las fases más iniciales.We analyze a series of 34 patients, 9 males and 25 females, with Freiberg's disease, detailing their location and severity at moment of the diagnosis. Clinically the severity of disease was variable, and frequently discordant with the radiological image. Only in 5 patients was necessary the surgical treatment. There was no etiologic factor clearly found in any of the cases, with and without traumatic precedents. We describe the radiological pattern of this disease. The MRI permits at early stage detection of bone anomalies