5,827 research outputs found
Test, Control and Monitor System (TCMS) operations plan
The purpose is to provide a clear understanding of the Test, Control and Monitor System (TCMS) operating environment and to describe the method of operations for TCMS. TCMS is a complex and sophisticated checkout system focused on support of the Space Station Freedom Program (SSFP) and related activities. An understanding of the TCMS operating environment is provided and operational responsibilities are defined. NASA and the Payload Ground Operations Contractor (PGOC) will use it as a guide to manage the operation of the TCMS computer systems and associated networks and workstations. All TCMS operational functions are examined. Other plans and detailed operating procedures relating to an individual operational function are referenced within this plan. This plan augments existing Technical Support Management Directives (TSMD's), Standard Practices, and other management documentation which will be followed where applicable
Anisotropic constitutive relationships in energetic materials: PETN and HMX
This paper presents results of first-principles density functional calculations of the equation of state (EOS) of PETN-I and beta-HMX. The isotropic EOS for hydrostatic compression has been extended to include uniaxial compressions in the [100], [010], [001], [110], [101], [011], and [111] directions up to compression ratio V/V0 = 0.70. Equilibrium properties, including lattice parameters and elastic constants, as well as hydrostatic EOS are in good agreement with available experimental data. The shear stresses of uniaxially compressed PETN-I and beta-HMX have been evaluated and their behavior as a function of compression ratio has been used to make predictions of shock sensitivity of these EMs. A comparison of predicted sensitivities with available experimental data has also been performed
First-principles anisotropic constitutive relationships in β-cyclotetramethylene tetranitramine (β-HMX)
First-principles density functional theory calculations have been performed to obtain constitutive relationships in the crystalline energetic material β-cyclotetramethylene tetranitramine (β-HMX). In addition to hydrostatic loading, uniaxial compressions in the directions normal to the {100}, {010}, {001}, {110}, {101}, {011}, and {111} planes have been performed to investigate the anisotropic equation of state (EOS). The calculated lattice parameters and hydrostatic EOS are in reasonable agreement with the available experimental data. The uniaxial compression data show a significant anisotropy in the principal stresses, change in energy, band gap, and shear stresses, which might lead to the anisotropy of the elastic-plastic shock transition and shock sensitivity of β-HMX
First-principles investigation of anisotropic constitutive relationships in pentaerythritol tetranitrate
First-principles density functional theory (DFT) calculations have been used to obtain the constitutive relationships of pentaerythritol tetranitrate (PETN-I), a crystalline energetic material. The isotropic equation of state (EOS) for hydrostatic compression has been extended to include uniaxial compressions in the , , , , , , and crystallographic directions up to a compression ratio of V/V0=0.70. DFT predicts equilibrium properties such as lattice parameters and elastic constants, as well as the hydrostatic EOS, in agreement with available experimental data. Our results show a substantial anisotropy of various properties of PETN-I upon uniaxial compression. To characterize the anisotropic traits of PETN, different physical properties of the uniaxially compressed crystal such as the energy per atom, band gap, and stress tensor have been evaluated as a function of compression ratio. The maximum shear stresses were calculated and examined for a correlation with the anisotropy in shock-initiation sensitivity
Density functional theory calculations of anisotropic constitutive relationships in alpha-cyclotrimethylenetrinitramine
Constitutive relationships in the crystalline energetic material alpha-cyclotrimethylenetrinitramine (alpha-RDX) have been investigated using first-principles density functional theory. The equilibrium properties of alpha-RDX including unit cell parameters and bulk modulus, as well as the hydrostatic equation of state (EOS), have been obtained and compared with available experimental data. The isotropic EOS has been extended to include the anisotropic response of alpha-RDX by performing uniaxial compressions normal to several low-index planes, {100}, {010}, {001}, {110}, {101}, {011}, and {111}, in the Pbca space group. The uniaxial-compression data exhibit a considerable anisotropy in the principal stresses, changes in energy, band gaps, and shear stresses, which might play a role in the anisotropic behavior of alpha-RDX under shock loading
Having burned the straw man of Christian spiritual leadership, what can we learn from Jesus about leading ethically?
In considering what it means to lead organizations effectively and ethically the literature comprising spirituality at work (SAW) and spiritual leadership theory (SLT) has become highly influential, especially in the USA. It has also attracted significant criticism. While, in this paper we endorse this critique, we argue that that the strand of literature which purportedly takes a Christian standpoint within the wider SAW school of thought, largely misconstrues and misapplies the teaching of its founder, Jesus. As a result, in dismissing the claims and application of SAW and SLT, there is a real risk that we lose the vital contribution of Christian thought, not least some of the timeless counter-cultural wisdom of Jesus which, we contend, offers a vital foundation to the practice of ethical leadership and business ethics in organisations. In proposing a way forward, two thorny issues which face all leaders are addressed: dealing with ego and closing the gap between what we say and what we do. The more we understand about the dynamics of human nature, the more we learn about the profundity of Jesus’ teachings. We then propose a number of ways in which Jesus-centred ethical leadership can be practised. Each is radical and each implies risk: both the personal risk of inner renewal arising from repentance as a doorway to personal integrity, as well as the risk of opposing unethical practices and promoting the excellence of core practices in the workplace
Análisis mediante modelos de multiestados del impacto de la viruela aviar sobre una población de Verdecillos (Serinus serinus): la importancia de estimar las tasas de recaptura
Disease is one of the evolutionary forces shaping populations. Recent studies have shown that epidemics like avian pox, malaria, or mycoplasmosis have affected passerine population dynamics, being responsible for the decline of some populations or disproportionately killing males and larger individuals and thus selecting for specific morphotypes. However, few studies have estimated the effects of an epidemic by following individual birds using the capture–recapture approach. Because avian pox can be diagnosed by direct examination of the birds, we are here able to analyze, using multistate models, the development and consequences of an avian pox epidemic affecting in 1996, a population of Serins (Serinus serinus) in northeastern Spain. The epidemics lasted from June to the end of November of 1996, with a maximum apparent prevalence rate > 30% in October. However, recapture rate of sick birds was very high (0.81, range 0.37–0.93) compared to that of healthy birds (0.21, range 0.02–0.32), which highly inflated apparent prevalence rate. This was additionally supported by the low predicted transition from the state of being uninfected to the state of being infected (0.03, SE 0.03). Once infected, Serin avian pox was very virulent with (15–day) survival rate of infected birds being of only 0.46 (SE 0.17) compared to that of healthy ones (0.87, SE 0.03). Probability of recovery from disease, provided that the bird survived the first two weeks, however, was very high (0.65, SE 0.25). The use of these estimates together with a simple model, allowed us to predict an asymptotic increase to prevalence of about 4% by the end of the outbreak period, followed by a sharp decline, with the only remaining infestations being infected birds that had not yet recovered. This is in contrast to the apparent prevalence of pox and stresses the need to estimate recapture rates when estimating population dynamics parameters.Las enfermedades infecciosas son una de las fuerzas evolutivas que modulan a las poblaciones animales. Estudios recientes han puesto de manifiesto como epidemias como la viruela aviar, la malaria o la mycoplasmosis afectan a la dinámica de las poblaciones de passeriformes, siendo responsables de dramáticas reducciones en el tamaño de algunas poblaciones, o de la muerte desproporcionada de machos o de los individuos de mayor tamaño, seleccionando de ese modo en favor de determinados morfotipos. Sin embargo, pocos estudios han estimado los efectos de una epidemia mediante el seguimiento de los distintos individuos utilizando las técnicas de captura–recaptura. Debido al hecho de que la viruela aviar puede ser diagnosticada mediante el examen directo de los individuos, hemos podido analizar, utilizando modelos de multiestado, el desarrollo y consecuencias de una epidemia de viruela aviar que afectó en 1996, a una población de Verdecillos en el nordeste de España. La epidemia afectó a los Verdecillos desde junio hasta finales de noviembre, con una prevalencia aparente máxima de > 30% en octubre. Sin embargo, la tasa de recaptura de los individuos enfermos fue muy alta (0,81, rango 0,37–0,93), comparada con la de los individuos sanos (0,21, rango 0,02–0,32), lo cual exageraba en gran medida la tasa de prevalencia aparente. Este resultado estaba adicionalmente apoyado por la baja tasa estimada de transición del estado de no infectado al estado de infectado (0,03, SE 0,03). Una vez un Verdecillo quedaba infectado, la viruela aviar resultó muy virulenta, siendo la tasa de supervivencia (a 15 dÃas) de los individuos enfermos de tan solo 0,46 (SE 0,17), comparada con la de los individuos no infectados (0,87, SE 0,03). La probabilidad de recuperación de la enfermedad, siempre y cuando el individuo hubiera sobrevivido las dos primeras semanas, fue sin embargo, muy alta (0,65, SE 0,25). Estos valores fueron utilizados para construir un modelo que permitió predecir el valor real de prevalencia de la enfermedad. Según el modelo, el porcentaje de individuos infectados después del brote debió incrementarse de forma asintótica hasta el 4%, manteniéndose en ese valor, hasta que se produjo una abrupta reducción en el número de individuos infectados al final de la epidemia, siendo estos los individuos que todavÃa no se habÃan recuperado de la enfermedad. Estos valores contrastan con los valores aparentes de prevalencia de la viruela y enfatiza la necesidad de estimar la tasa de recaptura cuando se realizan estimaciones de los distintos parámetros de dinámica de poblaciones
Forgiveness and interpersonal skills in same-sexed friendships
Although forgiveness is a largely interpersonal process, little research has examined the relationship between forgiveness and the interpersonal skills that may be important in forgiving another for an offence. The current study addressed this issue by investigating the relationship between forgiveness and interpersonal skills in same-sexed friendships among a community sample of 210 people (mean age 38.32 years). Each participant completed the Heartland Forgiveness Scale (Thompson et al., 2005), which assesses forgiveness of self, others, and situations; and the same-sex friend version of the Interpersonal Competence Questionnaire (Buhrmester, Furman, Wittenberg, & Reis, 1988) which assesses skills in initiation, negative assertion, self-disclosure, emotional support, and conflict management. Positive correlations were found between all five interpersonal skills and the three types of forgiveness, with only the relationship between forgiveness of others and negative assertion failing to reach significance. Separate hierarchical regressions were conducted to predict each type of forgiveness, with age and gender entered at Step 1 and the interpersonal skills variables entered at Step 2. Age, initiation skills, and conflict management skills each contributed uniquely to the prediction of all three types of forgiveness. Discussion centres around the relationship between forgiveness and interpersonal skills
Aplicación de la modelación integrada bayesiana y de los métodos Monte Carlo basados en cadenas de Markov para la conservación de una especie recolectada
When endeavoring to make informed decisions, conservation biologists must frequently contend with disparate sources of data and competing hypotheses about the likely impacts of proposed decisions on the resource status. Frequently, statistical analyses, modeling (e.g., for population projection) and optimization or simulation are conducted as separate exercises. For example, a population model might be constructed, whose parameters are then estimated from data (e.g., ringing studies, population surveys). This model might then be used to predict future population states, from current population estimates, under a particular management regime. Finally, the parameterized model might also be used to evaluate alternative candidate management decisions, via simulation, optimization, or both. This approach, while effective, does not take full advantage of the integration of data and model components for prediction and updating; we propose a hierarchical Bayesian context for this integration. In the case of American black ducks (Anas rubripes), managers are simultaneously faced with trying to extract a sustainable harvest from the species, while maintaining individual stocks above acceptable thresholds. The problem is complicated by spatial heterogeneity in the growth rates and carrying capacity of black ducks stocks, movement between stocks, regional differences in the intensity of harvest pressure, and heterogeneity in the degree of competition from a close congener, mallards (Anas platyrynchos) among stocks. We have constructed a population life cycle model that takes these components into account and simultaneously performs parameter estimation and population prediction in a Bayesian framework. Ringing data are used to develop posterior predictive distributions for harvest mortality rates, given as input decisions about harvest regulations. Population surveys of black ducks and mallards are used to obtain stock–specific estimates of population size for both species, for inputs into the population life–cycle model. These estimates are combined with the posterior distributions for harvest mortality, to obtain posterior predictive distributions of future population status for candidate sets of regional harvest regulations, under alternative biological hypotheses for black duck population dynamics. These distributions might then be used for both the exploration of optimal harvest policies and for sequential updating of model posteriors, via comparison of predictive distributions to future survey estimates of stock–specific abundance. Our approach illustrates advantages of MCMC for integrating disparate data sources into a common predictive framework, for use in conservation decision making.En el momento de tomar decisiones bien fundamentadas, es habitual que los biólogos conservacionistas deban enfrentarse a fuentes de datos dispares e hipótesis alternativas acerca de los impactos probables que tendrán las decisiones propuestas en el estado del recurso. A menudo, tanto los análisis estadÃsticos, como la modelación (para la proyección poblacional, por ejemplo) y la optimización o simulación, se llevan a cabo como ejercicios independientes. AsÃ, es posible que se construya un modelo poblacional, cuyos parámetros se estimen a partir de datos (como estudios de anillamiento y estudios poblacionales). Posteriormente, cabe la posibilidad de que este mismo modelo se emplee para predecir situaciones demográficas futuras a partir de las estimaciones de población actuales, utilizando para ello un sistema de gestión determinado. Por último, el modelo parametrizado también puede emplearse para evaluar posibles decisiones de gestión alternativas, a través de la simulación, la optimización, o ambos procedimientos. Si bien este enfoque resulta eficaz, no aprovecha al máximo la integración de datos y los componentes de los modelos para la predicción y actualización. En este estudio proponemos un contexto bayesiano jerárquico que permite efectuar dicha integración. En el caso del ánade sombrÃo americano (Anas rubripes), los gestores deben enfrentarse a la labor de intentar extraer una recolección sostenible de la especie, al tiempo que mantienen los stocks de individuos por encima de umbrales aceptables. El problema se ve agravado por la heterogeneidad espacial que presentan las tasas de crecimiento y la carga cinegética de los stocks de ánades sombrÃos, el movimiento entre los stocks, las diferencias regionales en la intensidad de la presión recolectora y la heterogeneidad en el grado de competencia por parte de un congénere cercano —el ánade real (Anas platyrynchos)— entre los stocks. Hemos formulado un modelo del ciclo vital de la población que toma en consideración estos componentes, al tiempo que permite llevar a cabo una estimación de los parámetros y una predicción de la población en un marco bayesiano. Los datos de anillamiento se emplean para desarrollar distribuciones predictivas posteriores para las tasas de mortalidad durante la recolección, expresadas como decisiones de entrada acerca de la normativa sobre recolecciones. Los estudios poblacionales del ánade sombrÃo y del ánade real se emplean para obtener estimaciones sobre el tamaño poblacional especÃficas de los stocks de ambas especies, que se emplearán como entradas para el modelo del ciclo vital de la población. Dichas estimaciones se combinan con las distribuciones posteriores para la mortalidad durante la recolección, con el propósito de obtener distribuciones predictivas posteriores de la situación demográfica futura para posibles conjuntos de normativas regionales acerca de la recolección, de acuerdo con hipótesis biológicas alternativas relativas a la dinámica poblacional del ánade sombrÃo. En una fase posterior, tales distribuciones pueden utilizarse tanto para la investigación de polÃticas óptimas en materia de recolección, como para la actualización secuencial de distribuciones posteriores del modelo mediante la comparación de distribuciones predictivas para estimaciones en estudios futuros acerca de la abundancia poblacional presente de forma especÃfica en los stocks. Nuestro enfoque ilustra las ventajas que presentan las técnicas de Montecarlo basadas encadenas de Markov (MCMC) para integrar fuentes de datos dispares en un marco predictivo común, con vistas a su utilización en la toma de decisiones sobre conservación
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