Diversity Of Short Gamma-Ray Burst Afterglows From Compact Binary Mergers Hosting Pulsars

Short gamma-ray bursts (sGRBs) are widely believed to result from the mergers of compact binaries. This model predicts an afterglow that bears the characteristic signatures of a constant, low density medium, including a smooth prompt-afterglow transition, and a simple temporal evolution. However, these expectations are in conflict with observations for a non-negligible fraction of sGRB afterglows. In particular, the onset of the afterglow phase for some of these events appears to be delayed and, in addition, a few of them exhibit late- time rapid fading in their lightcurves. We show that these peculiar observations can be explained independently of ongoing central engine activity if some sGRB progenitors are compact binaries hosting at least one pulsar. The Poynting flux emanating from the pulsar companion can excavate a bow-shock cavity surround- ing the binary. If this cavity is larger than the shock deceleration length scale in the undisturbed interstellar medium, then the onset of the afterglow will be delayed. Should the deceleration occur entirely within the swept-up thin shell, a rapid fade in the lightcurve will ensue. We identify two types of pulsar that can achieve the conditions necessary for altering the afterglow: low field, long lived pulsars, and high field pulsars. We find that a sizable fraction (~20-50%) of low field pulsars are likely to reside in neutron star binaries based on observations, while their high field counterparts are not. Hydrodynamical calculations motivated by this model are shown to be in good agreement with observations of sGRB afterglow lightcurves.Comment: Accepted to ApjL. Direct comparison to observed X-Ray afterglows now included. 5 Figure

Towards a complex system of personal and group characteristics for ICT appropriation

This research tackles the phenomenon of digital inclusion, considered as a type of social development that has grown, due to the advance of information and communication technologies (ICT). It is worth noting that, the "ICT advance" has not been uniformly distributed, since there is a difference regarding the access to technology, and to the use of it among groups and people. Though the governments, the organizations and the ICT institutions, recognize the social nature of the digital inclusion, and also, they are aware of the necessity of integrating communities and people, with the process of program and/or project management; these people and communities are not considered, in the proposals that are being made about this issue. Likewise, though it is clear in the revision of literature, the necessity of having quantitative and qualitative approaches, the numerical approach that is being performed in the phenomenon is evident. Additionally, it has been identified the fact that, there are diverse personal and social characteristics, that allow the appropriation of ICT tools, as well as their use to achieve goals and to improve the conditions, for participating in the employment, education and political activities. The digital inclusion is a situation that involves different factors, such as: cultural, technical, social, financial, regulatory, moral and even ecological. If this topic is tackled in a quantitative way, the aforementioned factors seem to be unrelated. However, in the literature analysis, their relation is obvious, as well as the fact that they cannot be unrelated form one another. In other words, the elements that conform the digital inclusion phenomenon, are not only heterogeneous, but also inter-definable. The former statement justifies the analysis of the digital inclusion phenomenon, as a complex system; since regarding the ICT appropriation, there is a wide variety of proposals, considering the personal and social variables, that regulate this process. Nevertheless, there is not yet a consensus about these variables, which is the proposal presented in this paper

An Architecture for Biometric Electronic Identification Document System Based on Blockchain †

This paper proposes an architecture for biometric electronic identification document (e-ID) system based on Blockchain for citizens identity verification in transactions corresponding to the notary, registration, tax declaration and payment, basic health services and registration of economic activities, among others. To validate the user authentication, a biometric e-ID system is used to avoid spoofing and related attacks. Also, to validate the document a digital certificate is used with the corresponding public and private key for each citizen by using a user’s PIN. The proposed transaction validation process was implemented on a Blockchain system in order to record and verify the transactions made by all citizens registered in the electoral census, which guarantees security, integrity, scalability, traceability, and no-ambiguity. Additionally, a Blockchain network architecture is presented in a distributed and decentralized way including all the nodes of the network, database and government entities such as national register and notary offices. The results of the application of a new consensus algorithm to our Blockchain network are also presented showing mining time, memory and CPU usage when the number of transactions scales up

Relación entre ruido por carga vehicular, molestia y atención escolar en estudiantes de nivel básico de la ciudad de Toluca 2004

Dos escuelas públicas de la ciudad de Toluca con diferente afluencia vehicular fueron seleccionadas para el estudio. Se realizaron medidas internas y externas de los niveles de ruido; los niveles de ruido encontrados sobrepasan los recomendados por la oms. Se aplicaron dos test de atención a los alumnos de las escuelas. El nivel de atención fue mejor para la escuela con menos tránsito. En el personal de ambas escuelas hubo molestia causada por el ruido vehicular.Dos escuelas públicas de la ciudad de Toluca con diferente aÁuencia vehicular fueron seleccionadas para el estudio. Se realizaron medidas internas y externas de los niveles de ruido; los niveles de ruido encontrados sobrepasan los recomendados por la oms. Se aplicaron dos test de atención a los alumnos de las escuelas. El nivel de atención fue mejor para la escuela con menos tránsito. En el personal de ambas escuelas hubo molestia causada por el ruido vehicular

Incidencia de antígeno australiano en donantes profesionales del instituto salvadoreño del seguro social, utilizando la técnica de radioinmunoensayo hepria b

Con el objeto de establecer la prevalencia del antígeno australiano en la sangre de donantes profesionales considerados sanos que donan su sangre al Instituto salvadoreño del seguro social, se procesaron 1121 muestras de sueros utilizando la técnica de radioinmunoensayo (ria) hepria b. Se obtuvo una positividad del 1.4% y un 98.6% de negatividad, este porcentaje nos indica que en nuestro medio la hepatitis post transfusional representa un problema realmente serio. Encontramos que el método ria hepria b es una prueba práctica, sencilla y específica, recomendándola como un método básico de rutina para la investigación del agshb en la sangre de los donadores que donan este producto biológico a los bancos de sangre. De esta forma el rechazo de estos donadores reduciría la transmisión parenteral del agente de hepatitis b, en el uso de la hemoterapia

RURAL TOURISM, ENVIRONMENTAL IMPACT AND RESILIENCE IN PIEDRA HERRADA, MEXICO

Se analizó el impacto que genera el turismo rural en el ejido Piedra Herrada, ubicado en el municipio de Temascaltepec, Estado de México (México), que se caracteriza por el aprovechamiento turístico del proceso de hibernación de la mariposa monarca (Danausplexippus L.), a partir de la valoración de la resiliencia. Para ello se retoman las aportaciones de Martín-López et al. (2009) para determinar el sistema socio ecológico (SSE) del lugar de estudio, así como Strickland-Munro et al. (2010) y Santos (2012) para el análisis de los impactos del turismo en áreas naturales protegidas (ANP), a partir de la resiliencia y los criterios de valoración: perturbaciones, vulnerabilidad, conectividad y potencial de cambio. Se identificó que el turismo está generando beneficios económicos para la población local, que a su vez incide en la conservación del entorno forestal y el hábitat de la mariposa monarca; no obstante, el SSE es sensible a la dinámica e intensificación de la actividad turística, con alcance sobre la conservación del suelo y la biodiversidad, por lo que es necesario delinear estrategias que favorezcan la conservación ambiental y el adecuado desarrollo del turismo rural