Boundary conditions for hyperbolic formulations of the Einstein equations

In regards to the initial-boundary value problem of the Einstein equations, we argue that the projection of the Einstein equations along the normal to the boundary yields necessary and appropriate boundary conditions for a wide class of equivalent formulations. We explicitly show that this is so for the Einstein-Christoffel formulation of the Einstein equations in the case of spherical symmetry.Comment: 15 pages; text added and typesetting errors corrected; to appear in Classical and Quantum Gravit

Propuesta de un plan de negocio, basado en tecnolog?a, para atenci?n de consultas e incidentes relacionados a dispositivos electr?nicos

El servicio de soporte t?cnico se ha venido prestando de manera tradicional a lo largo del tiempo. Sin embargo, no se ha evidenciado la existencia de alg?n proveedor, que brinde este servicio de manera integral, siendo independiente del dispositivo, marca y plataforma. En ese sentido, la presente tesis, propone un modelo de negocio que, fundament?ndose en tecnolog?a como elemento diferenciador, busca atender las consultas e incidentes de los usuarios de manera integral, eliminando la complejidad de buscar al proveedor que compete un determinado incidente. Asimismo, el uso de tecnolog?a, permitir? brindar un primer nivel de servicio totalmente gratuito, y otro pagado, que ser? el que generar?a ingresos a la empresa. En ambos casos, se buscar? maximizar la eficiencia en cuanto a operaciones y calidad del servicio. Finalmente, se ha contemplado tambi?n el uso de tecnolog?a anal?tica, que permita mejorar las operaciones de la empresa a lo largo del tiempo. Por ejemplo, mediante la consulta a bases de datos de conocimiento, lo cual permitir? una mayor eficiencia en la soluci?n de incidentes

High rate of uncovered struts in latest generation drug-eluting stents with durable, biodegradable polymer or lack of it 1 month after implantation

Introduction and objectives: Delayed vascular healing may induce late stent thrombosis. Optical coherence tomography (OCT) is useful to evaluate endothelial coverage. The objective of this study was to compare stent coverage and apposition in non-complex coronary artery lesions treated with durable polymer-coated everolimus-eluting stents (durable-polymer EES) vs biodegradable polymer-coated everolimus-eluting stents ( biodegradable-polymer EES) vs polymer-free biolimus-eluting stents (BES) 1 and 6 months after stent implantation. Methods: Prospective, multicenter, non-randomized study that compared the 3 types of DES. Follow-up angiography and OCT were performed 1 and 6 months later. The primary endpoint was the rate of uncovered struts as assessed by the OCT at 1 month. Results: A total of 104 patients with de novo non-complex coronary artery lesions were enrolled. A total of 44 patients were treated with polymer-free BES, 35 with biodegradable-polymer EES, and 25 with durable-polymer EES. A high rate of uncovered struts was found at 1 month with no significant differences reported among the stents (80.2%, polymer-free BES; 88.1%, biodegradable-polymer EES; 82.5%, durable-polymer EES; P =.209). Coverage improved after 6 months in the 3 groups without significant differences being reported (97%, 95%, and 93.7%, respectively; P =.172). Conclusions: In patients with de novo non-complex coronary artery lesions treated with durable vs biodegradable vs polymer-free DES, strut coverage and apposition were suboptimal at 1 month with significant improvement at 6 months

Coastal high-frequency radars in the Mediterranean ??? Part 2: Applications in support of science priorities and societal needs

International audienceThe Mediterranean Sea is a prominent climate-change hot spot, with many socioeconomically vital coastal areas being the most vulnerable targets for maritime safety, diverse met-ocean hazards and marine pollution. Providing an unprecedented spatial and temporal resolution at wide coastal areas, high-frequency radars (HFRs) have been steadily gaining recognition as an effective land-based remote sensing technology for continuous monitoring of the surface circulation, increasingly waves and occasionally winds. HFR measurements have boosted the thorough scientific knowledge of coastal processes, also fostering a broad range of applications, which has promoted their integration in coastal ocean observing systems worldwide, with more than half of the European sites located in the Mediterranean coastal areas. In this work, we present a review of existing HFR data multidisciplinary science-based applications in the Mediterranean Sea, primarily focused on meeting end-user and science-driven requirements, addressing regional challenges in three main topics: (i) maritime safety, (ii) extreme hazards and (iii) environmental transport process. Additionally, the HFR observing and monitoring regional capabilities in the Mediterranean coastal areas required to underpin the underlying science and the further development of applications are also analyzed. The outcome of this assessment has allowed us to provide a set of recommendations for future improvement prospects to maximize the contribution to extending science-based HFR products into societally relevant downstream services to support blue growth in the Mediterranean coastal areas, helping to meet the UN's Decade of Ocean Science for Sustainable Development and the EU's Green Deal goals

Coastal high-frequency radars in the Mediterranean ??? Part 1: Status of operations and a framework for future development

Due to the semi-enclosed nature of the Mediterranean Sea, natural disasters and anthropogenic activities impose stronger pressures on its coastal ecosystems than in any other sea of the world.With the aim of responding adequately to science priorities and societal challenges, littoral waters must be effectively monitored with high-frequency radar (HFR) systems. This land-based remote sensing technology can provide, in near-real time, fine-resolution maps of the surface circulation over broad coastal areas, along with reliable directional wave and wind information. The main goal of this work is to showcase the current status of the Mediterranean HFR network and the future roadmap for orchestrated actions. Ongoing collaborative efforts and recent progress of this regional alliance are not only described but also connected with other European initiatives and global frameworks, highlighting the advantages of this cost-effective instrument for the multi-parameter monitoring of the sea state. Coordinated endeavors between HFR operators from different multi-disciplinary institutions are mandatory to reach a mature stage at both national and regional levels, striving to do the following: (i) harmonize deployment and maintenance practices; (ii) standardize data, metadata, and quality control procedures; (iii) centralize data management, visualization, and access platforms; and (iv) develop practical applications of societal benefit that can be used for strategic planning and informed decision-making in the Mediterranean marine environment. Such fit-for-purpose applications can serve for search and rescue operations, safe vessel navigation, tracking of marine pollutants, the monitoring of extreme events, the investigation of transport processes, and the connectivity between offshore waters and coastal ecosystems. Finally, future prospects within the Mediterranean framework are discussed along with a wealth of socioeconomic, technical, and scientific challenges to be faced during the implementatio

New insights into the genetic etiology of Alzheimer's disease and related dementias

Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

AISLAMIENTO DE CEPAS NATIVAS DE TRICHODERMA SPP DE SUELOS HORTICOLAS DEL VALLE DE TOLUCA, COMO BIOCONTROL POTENCIAL DE SCLEROTINIA

Se evaluó la presencia de Trichoderma en siete localidades en la zona sur del Valle de Toluca, Estado de México. Esta es un área con un alto potencial en la producción de hortalizas. El estudio se dirigió al aislamiento de cepas nativas de Trichoderma a partir de muestras de suelo, identificación de factores fisiográficos, así como las propiedades físicas y químicas del suelo que determinan la ocurrencia de Trichoderma. Se evaluó el potencial de las cepas de Trichoderma para el control de Sclerotinia spp., hongo patógeno causante de la pudrición blanda en lechuga. Se aislaron once cepas, el mayor número de ellas asociadas al tipo de suelo se encontró en las localidades de San Francisco Putla y San Francisco Tetetla. El análisis de regresión logística mostró que no hay una relación entre las propiedades del suelo (materia orgánica y pH) y la presencia de Trichoderma. La prueba de Tukey (

?El inicio de un procedimiento contencioso administrativo debido a la clasificaci?n arancelaria de una mercanc?a exportada es una causal de suspensi?n del plazo del r?gimen de restituci?n simplificada de derechos arancelarios - Drawback?

Partiendo del Principio de Facilitaci?n del Comercio Exterior regulado en la Ley General de Aduanas, la Administraci?n Aduanera debe promover el desarrollo nacional a trav?s de la correcta prestaci?n de sus servicios; no obstante, en casos cuando el exportador pretende acogerse al r?gimen del Drawback y para ello debe defender la clasificaci?n arancelaria de la mercanc?a a trav?s de un procedimiento contencioso administrativo, la defensa de este se ve afectada cuando el procedimiento en menci?n no es considerado como causal de suspensi?n del plazo para acogerse al referido r?gimen. El objetivo de esta investigaci?n es demostrar la situaci?n de indefensi?n en la que se encuentra el exportador y la necesidad de cambio de criterio de interpretaci?n de la norma por parte de la Administraci?n Aduanera y el Tribunal Fiscal, lo cual conlleva a determinar como el inicio de un procedimiento contencioso administrativo debe ser considerado causal de suspensi?n del plazo para acogerse al r?gimen del Drawback. La presente investigaci?n utiliz? un m?todo cualitativo descriptivo: te?rico, anal?tico y inductivo. El an?lisis muestra que la Administraci?n Aduanera est? realizando una interpretaci?n literal del art?culo 138 de la Ley General de Aduanas que genera un perjuicio en el r?gimen del Drawback; perjuicio que esta investigaci?n pretende resolver