Single Injection Earth Return Trajectory Options for Small Spacecraft Missions to the Moon

There exist several classes of high energy trajectories that are injected from Earth centered orbits to deep space destinations and return to the vicinity of the Earth sometime later due to the direct influence of a third body perturbation. These trajectories can be designed to flyby the moon or near Earth asteroids and comets. The appealing characteristic of these trajectories is that they require a single injection maneuver at the Earth and no further translational control thereafter. A spacecraft on such a trajectory can take observations and measurements of the flyby body and download the data once it returns to the vicinity of the Earth. The return trajectory could place the spacecraft into a direct reentry path through the Earth\u27s atmosphere or an elliptical or hyperbolic Earth flyby that will be completely passive since no maneuvers are made. This type of trajectory is applicable to passive spacecraft missions such as student built micro satellites that have no on board propulsion for attitude or translational control. Issues addressed are the dispersions in the return trajectory due to errors in the injection maneuver and other orbit parameters. The characteristics of an Earth return lunar flyby mission for small satellites are discussed

Theoretical Foundation of Copernicus: A Unified System for Trajectory Design and Optimization

The fundamental methods are described for the general spacecraft trajectory design and optimization software system called Copernicus. The methods rely on a unified framework that is used to model, design, and optimize spacecraft trajectories that may operate in complex gravitational force fields, use multiple propulsion systems, and involve multiple spacecraft. The trajectory model, with its associated equations of motion and maneuver models, are discussed

Virtual braid groups, virtual twin groups and crystallographic groups

Let $n\ge 2$. Let $VB_n$ (resp. $VP_n$) be the virtual braid group (resp. the pure virtual braid group), and let $VT_n$ (resp. $PVT_n$) be the virtual twin group (resp. the pure virtual twin group). Let $\Pi$ be one of the following quotients: $VB_n/\Gamma_2(VP_n)$ or $VT_n/\Gamma_2(PVT_n)$ where $\Gamma_2(H)$ is the commutator subgroup of $H$. In this paper, we show that $\Pi$ is a crystallographic group and we characterize the elements of finite order and the conjugacy classes of elements in $\Pi$. Furthermore, we realize explicitly some Bieberbach groups and infinite virtually cyclic groups in $\Pi$. Finally, we also study other braid-like groups (welded, unrestricted, flat virtual, flat welded and Gauss virtual braid group) module the respective commutator subgroup in each case.Comment: In this new version some general results were added in Section

IMPACTO DE LA INTIMIDAD SOCIAL DEL PERSONAL DE ENFEMERIA CON PACIENTES EN EL TRATAMIENTO AMBULATORIO DE HEMODIALISIS

En diversas ocasiones las relaciones interpersonales entre el personal de enfermería y el paciente no son de relevancia para ninguno de los dos, sin embargo, es importante observar si esta relación puede afectar las intervenciones que se realizan con el paciente. Se llevó a cabo esta investigación de tipo cuantitativo que involucro a 25 individuos del personal de enfermería, trabajaron con 2 pacientes distintos, este estudio se realizó en la Ciudad de México en un Hospital de 3° nivel de atención, mediante el uso del Test de Intimidad Social de Miller. Con 5 variables relacionadas con parámetros modificables en hemodiálisis e intimidad social, se realizaron análisis estadísticos usando la prueba exacta de Fisher, posteriormente al ingresar los datos se encontró que existe correlación estadística entre la intensidad de la intimidad social y la modificación de parámetros de hemodiálisisOn several occasions, interpersonal relationships between nurses and patients are of no relevance to either of the two, however, it is important to note whether this relationship may affect the interventions that are carried out with the patient. Therefore, this quantitative type investigation involving 25 individuals of the nurses who worked with 2 different patients was carried out, this study was conducted in Mexico City in a Hospital of 3rd level of care, through the use of Miller's Social intimacy Test. With 5 variables related to parameters modifiable in hemodialysis and social intimacy, statistical analyses were performed using the exact test of Fisher, then when the data was entered it was found that there is statistical correlation between the Intensity of social intimacy and modification of hemodialysis parameter

An Alternative Humans to Mars Approach: Reducing Mission Mass with Multiple Mars Flyby Trajectories and Minimal Capability Investments

Mars flyby trajectories and Earth return trajectories have the potential to enable lower- cost and sustainable human exploration of Mars. Flyby and return trajectories are true minimum energy paths with low to zero post-Earth departure maneuvers. By emplacing the large crew vehicles required for human transit on these paths, the total fuel cost can be reduced. The traditional full-up repeating Earth-Mars-Earth cycler concept requires significant infrastructure, but a Mars only flyby approach minimizes mission mass and maximizes opportunities to build-up missions in a stepwise manner. In this paper multiple strategies for sending a crew of 4 to Mars orbit and back are examined. With pre-emplaced assets in Mars orbit, a transit habitat and a minimally functional Mars taxi, a complete Mars mission can be accomplished in 3 SLS launches and 2 Mars Flyby's, including Orion. While some years are better than others, ample opportunities exist within a given 15-year Earth-Mars alignment cycle. Building up a mission cadence over time, this approach can translate to Mars surface access. Risk reduction, which is always a concern for human missions, is mitigated by the use of flybys with Earth return (some of which are true free returns) capability

¿En época de crisis, es factible construir el futuro?

Prosperity, is to live happy and stay without effort; It is the peace of mind that everything you need to perform and / or succeed in life. Consequently, economic growth should be in sound logic, leading to the instrument creating greater prosperity. As incomes grow, should also improve the chances of realization, to enjoy a more comfortable life rich in short, to acquire a higher level of well-being and quality of life. That is, at least, which in theory is supposed to happen. Today, however, things are not so easily satisfied with that view. Global economic growth, propelled in large amount by submission to mere profit and profit, is in doubt and danger. In times of crisis, organizations must find tools or methodologies that enable them to build their future, and thus make the best decisions.Prosperity, is to live happy and stay without effort; It is the peace of mind that everything you need to perform and / or succeed in life. Consequently, economic growth should be in sound logic, leading to the instrument creating greater prosperity. As incomes grow, should also improve the chances of realization, to enjoy a more comfortable life rich in short, to acquire a higher level of well-being and quality of life. That is, at least, which in theory is supposed to happen. Today, however, things are not so easily satisfied with that view. Global economic growth, propelled in large amount by submission to mere profit and profit, is in doubt and danger. In times of crisis, organizations must find tools or methodologies that enable them to build their future, and thus make the best decisions

El diseño del laboratorio de física como herramienta para la resignificación de conceptos matemáticos

La presente ponencia resume el inicio de la construcción de un laboratorio de física y matemáticas en el programa de la Licenciatura en Matemáticas y Tecnologías de la Información, de la Universidad La Gran Colombia. Se presenta la experiencia en el diseño de la primera actividad y de los constructos teóricos y prácticos que se tuvieron en cuenta. Esta experiencia de aula está avalada dentro de la conformación de un semillero de investigación de la facultad, y muestra cómo a partir de un sistema masaresorte se pueden construir algunos conceptos fundamentales como el período de funciones, el comportamiento de las mismas y destacar la importancia del modelado de datos para su respectivo análisis y obtener así una aproximación por medio de la matemática

Opportunity to adopt marketing orientation strategies and orientation to the management of the supply chain in the detail sector: a case of study

El negocio del retail es una de las actividades empresariales más pujantes y de mayor importancia dentro del comercio en Colombia y el mundo, tanto así que las principales empresas existentes pertenecen a esta industria. En Colombia, el retail, es muy importante respecto de su aporte a diversos indicadores claves para la sociedad y su economía. Dentro de este contexto es importante señalar los puntos de encuentro entre estas teorías a través del análisis de un caso de estudio en una tienda que represente este modelo de negocio. Este artículo pretende realizar esa aproximación a través de una revisión teórica de ambos campos de conocimiento.La investigación se realizó mediante el método empírico, utilizando instrumentos de medición mediante entrevistas semiestructuradas aplicada a clientes del retail analizado, donde se analizó los criterios como la fidelidad, el servicio al cliente y la distribución física, componentes importantes en el valor agregado del proceso de entrega en el retail.Al final del estudio del caso se encontró que el retail, no solo presenta una fuerte relación con las estrategias de las hoy denominadas tiendas novedosas de barrio, sino que sus contribuciones son destacables en el mejoramiento de la canasta familiar de los clientes impacto el nivel de servicio.Además se observó que el sector debe fortalecer  tanto la estrategia de la orientación a la cadena de abastecimiento como la orientación al mercado, considerando  que son máximas que deben aplicarse y mantenerse en el sector, para una mejora del desempeño organizacional, criterio fundamental para la mejora de la competitividad para Colombia.La orientación al mercado, posee una influencia positiva en la orientación a la cadena de abastecimiento y a su vez a la gestión de la cadena de abastecimiento, impactando en el desempeño organizacional.The retail business is one of the busiest and most important business activities within the trade in Colombia and the world, so much so that the major companies are in an industry. In Colombia, retail trade is very important in relation to its contribution to various key indicators for society and its economy. Within this context it is important to point out the points of encounter between these theories through the analysis of a case study in a store that represents this business model. This article intends to make this approach through a theoretical revision of both fields of knowledge. The research was performed using the empirical method, using methods of measurement and semi-structured interviews applied to customers in the retail sector, where criteria such as fidelity, customer service and physical distribution were analyzed, important components in the added value of the process of delivery in the retail trade. At the end of the case study it was found that the retail, no single relationship relationship of a single presentation with the strategies of the hot sales girls of the children Service. It was also observed that the sector must consolidate both the supply chain orientation strategy and the market orientation, considering that the maxima that are applied and maintained in the sector, for the improvement of organizational performance, a fundamental criterion for the Improvement of competitiveness for Colombia. Market orientation has a positive influence on supply chain orientation and once on supply chain management, impacting on organizational performance.

Cadena de abastecimiento verde en empresa textil colombiana

This article aims to enunciate some logistic practices within the process of selection and evaluation of suppliers in a company of the textile sector in Bogotá. We hope to contribute to the improvement of the current process, through the inclusion of environmental factors and the determination of key strategies for converting local suppliers into global.El presente artículo pretende enunciar algunas prácticas logísticas dentro del proceso de selección y evaluación de proveedores en una empresa del sector textil en Bogotá. Se busca contribuir a la mejora del proceso actual, mediante la inclusión de factores medioambientales y la determinación de estrategias clave para convertir proveedores locales en globales

Actualización de documentación del proceso soporte logístico de la Gobernación de Antioquia dentro del Sistema Integrado de Gestión

La Subsecretaría de Servicios administrativos perteneciente a la Secretaría de Servicios y Suministros, tiene como funciones principales definir y dirigir las políticas, procedimientos y directrices para la adquisición de bienes y servicios del nivel central de la Administración Departamental. Debido a la nueva estructura administrativa de la entidad en la cual se dictan nuevas funciones a sus organismos y dependencias, en este trabajo se presenta la actualización de la documentación del proceso Soporte Logístico de acuerdo al Sistema Integrado de Gestión, actualizaciones y mejoras para las herramientas de consolidación del PAA conforme a las necesidades identificadas en cada dependencia que dado a estos cambios se hace necesario la inclusión de nuevos documentos, mejoras en el desarrollo de los procedimientos e instructivos en donde son designados nuevos encargados, además la incorporación de nuevos conocimientos en donde permitirá estar en una constante mejora continua. La metodología utilizada para el desarrollo de este trabajo se dio a partir del estudio de la información documentada de la organización y el conocimiento que tiene cada persona acerca de la función que desempeña, realizando una actualización de la información obtenida, dando inicio por la revisión de la documentación actual: procedimientos, instructivos, manuales y formatos; identificando posibles mejoras dentro del proceso para el logro de los objetivos propuestos