969 resultados para George C. Marshall Space Flight Center.


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El presente trabajo tiene por objeto presentar la primera aproximación a las relaciones interétnicas en el escenario del Fuerte San José y el Puesto de la Fuente, desde una perspectiva histórica y arqueológica. En particular, presentaremos los primeros resultados de las investigaciones históricas respecto de la problemática mencionada, sobre la base de información inédita analizada hasta el momento. Para ello nos centraremos en los primeros diez años de vida en el Fuerte (1779-1789) y estableceremos una comparación con los otros dos asentamientos que formaron parte del plan de poblamiento español de las costa patagónica (siglo XVIII): el Fuerte Nuestra Señora del Carmen y la Nueva Colonia de Floridablanca, a los efectos de destacar la particularidad del Fuerte San José en el marco de la variabilidad de la estructuración de las relaciones interétnicas en las colonias patagónicas.

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This study considers a dual-hop cognitive inter-vehicular relay-assisted communication system where all
communication links are non-line of sight ones and their fading is modelled by the double Rayleigh fading distribution.
Road-side relays (or access points) implementing the decode-and-forward relaying protocol are employed and one of
them is selected according to a predetermined policy to enable communication between vehicles. The performance of
the considered cognitive cooperative system is investigated for Kth best partial and full relay selection (RS) as well as
for two distinct fading scenarios. In the first scenario, all channels are double Rayleigh distributed. In the second
scenario, only the secondary source to relay and relay to destination channels are considered to be subject to double
Rayleigh fading whereas, channels between the secondary transmitters and the primary user are modelled by the
Rayleigh distribution. Exact and approximate expressions for the outage probability performance for all considered RS
policies and fading scenarios are presented. In addition to the analytical results, complementary computer simulated
performance evaluation results have been obtained by means of Monte Carlo simulations. The perfect match between
these two sets of results has verified the accuracy of the proposed mathematical analysis.

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Photographs and correspondence between A.E. Gordon and Charles Babcock

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In vivo and in vitro experiments were conducted to determine digestibility of GE and nutrients, as well as DE and ME of carbohydrates fed to growing pigs. The objective of Exp. 1 was to determine the DE and ME of 4 novel carbohydrates fed to pigs. The 4 novel carbohydrates were 2 sources of resistant starch (RS 60 and RS 70), soluble corn fiber (SCF), and pullulan. These carbohydrates were produced to increase total dietary fiber (TDF) intake by humans. Maltodextrin (MD) was used as a highly digestible control carbohydrate. The DE and ME for RS 60 (1,779 and 1,903 kcal/kg, respectively), RS 75(1,784 and 1,677 kcal/kg, respectively), and SCF (1,936 and 1,712 kcal/kg, respectively) were less (P < 0.05) than for MD (3,465 and 3,344 kcal/kg, respectively) and pullulan (2,755 and 2,766 kcal/kg, respectively), and pullulan contained less (P < 0.05) DE and ME than MD. However, there was no difference in the DE and ME for RS 60, RS 75, and SCF. The varying degrees of small intestinal digestibility and differences in fermentability among these novel carbohydrates may explain the differences in the DE and ME among carbohydrates. Therefore, the objectives of Exp. 2 were to determine the effect of these 4 novel carbohydrates and cellulose on apparent ileal (AID) and apparent total tract (ATTD) disappearance, and hindgut disappearance (HGD) of GE, TDF, and nutrients when added to diets fed to ileal-cannulated pigs. The second objective was to measure the endogenous flow of TDF to be able to calculate the standardized ileal disappearance (SID) and standardized total tract (STTD) disappearance of TDF in the 4 novel fibers fed to pigs. Results of the experiment indicated that the AID of GE and DM in diets containing cellulose or the novel fibers was less (P < 0.05) than of the maltodextrin diet, but the ATTD of GE and DM was not different among diets. The addition of RS 60, RS 75, and SCF did not affect the AID of acid hydrolysed ether extract (AEE), CP, or ash, but the addition of cellulose and pullulan reduced (P < 0.01) the AID of CP. The average ileal and total tract endogenous losses of TDF were calculated to be 25.25 and 42.87 g/kg DMI, respectively. The SID of TDF in diets containing RS 60, SCF, and pullulan were greater (P < 0.01) than the SID of TDF in the cellulose diet, but the STTD of the SCF diet was greater (P < 0.05) than for the cellulose and pullulan diets. Results of this experiment indicate that the presence of TDF reduces small intestinal disappearance of total carbohydrates and energy which may reduce the DE and ME of diets and ingredients. Therefore, the objective of Exp. 3 was to determine the DE and ME in yellow dent corn, Nutridense corn, dehulled barley, dehulled oats, polished rice, rye, sorghum, and wheat fed to growing pigs and to determine the AID and ATTD of GE, OM, CP, AEE, starch, total carbohydrates, and TDF in these cereal grains fed to pigs. Results indicated that the AID of GE, OM, and total carbohydrates was greater (P < 0.001) in rice than in all other cereal grains. The AID of starch was also greater (P < 0.001) in rice than in yellow dent corn, dehulled barley, rye, and wheat. The ATTD of GE was greater (P < 0.001) in rice than in yellow dent corn, rye, sorghum, and wheat. With a few exceptions, the AID and ATTD of GE and nutrients in Nutridense corn was not different from the values for dehulled oats. Likewise, with a few exceptions, the AID, ATTD, and HGD of GE, OM, total carbohydrates, and TDF in yellow corn, sorghum, and wheat were not different from each other. The AID of GE and AEE in dehulled barley was greater (P < 0.001) than in rye. The ATTD of GE and most nutrients was greater (P < 0.001) in dehulled barley than in rye. Dehulled oats had the greatest (P < 0.001) ME (kcal/kg DM) whereas rye had the least ME (kcal/kg DM) among the cereal grains. Results of the experiment indicate that the presence of TDF and RS may reduce small intestinal digestibility of starch in cereal grains resulting in reduced DE and ME in these grains. Digestibility experiments involving animals are time consuming and expensive. Therefore, the objective of Exp. 4 was to correlate DM and OM digestibility obtained from 3 in vitro procedures with ATTD of GE and with the concentration of DE in 50 corn samples that were fed to growing pigs. The second objective was to develop a regression model that can predict the ATTD of GE or the concentration of DE in corn. The third objective was to evaluate the suitability of using the DaisyII incubator as an alternative to the traditional water bath when determining in vitro DM and OM digestibility. Results indicated that corn samples incubated with Viscozyme for 48 h in the DaisyII incubator improved (P < 0.001) the ability of the procedure to detect small differences in the ATTD of GE or to detect small differences in the concentration of DE in corn. Likewise, compared with using cellulase or fecal inoculum, the variability in the ATTD of GE and the variability in the DE in corn was better (R2 = 0.56; P < 0.05 and R2 = 0.53; P < 0.06, respectively) explained if Viscozyme was used than if cellulase or fecal inoculum was used. A validated regression model that predicted the DE in corn was developed using Viscozyme and with the corn samples incubated in the DaisyII incubator for a 48 h. In conclusion, this present work used the pig as a model for human gastrointestinal function and evaluates carbohydrates from 2 different nutritional perspectives – humans and animals. The addition of novel carbohydrates reduced the digestibility of energy in the diets without necessarily reducing the digestibility of other nutrients. Thus, supplementation of novel carbohydrates in the diets may be beneficial for the management of diabetes. Aside from diabetic management, cereal grains such as rye and sorghum, may also help in BW management because of there low caloric value, but for undernourished individuals, dehulled oats, dehulled barley, and rice are the ideal grains. From an animal nutrition standpoint, high concentration of dietary fiber is undesirable because it reduces feed efficiency. Therefore, the inclusion of feed ingredients that have a high concentration of dietary fiber is often limited in animal diets. Although in vivo determination is ideal, in vitro procedures are useful tools to determine caloric value of food and feed ingredients.

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Forests have a prominent role in carbon storage and sequestration. Anthropogenic forcing has the potential to accelerate climate change and alter the distribution of forests. How forests redistribute spatially and temporally in response to climate change can alter their carbon sequestration potential. The driving question for this research was: How does plant migration from climate change impact vegetation distribution and carbon sequestration potential over continental scales? Large-scale simulation of the equilibrium response of vegetation and carbon from future climate change has shown relatively modest net gains in sequestration potential, but studies of the transient response has been limited to the sub-continent or landscape scale. The transient response depends on fine scale processes such as competition, disturbance, landscape characteristics, dispersal, and other factors, which makes it computational prohibitive at large domain sizes. To address this, this research used an advanced mechanistic model (Ecosystem Demography Model, ED) that is individually based, but pseudo-spatial, that reduces computational intensity while maintaining the fine scale processes that drive the transient response. First, the model was validated against remote sensing data for current plant functional type distribution in northern North America with a current climatology, and then a future climatology was used to predict the potential equilibrium redistribution of vegetation and carbon from future climate change. Next, to enable transient calculations, a method was developed to simulate the spatially explicit process of dispersal in pseudo-spatial modeling frameworks. Finally, the new dispersal sub-model was implemented in the mechanistic ecosystem model, and a model experimental design was designed and completed to estimate the transient response of vegetation and carbon to climate change. The potential equilibrium forest response to future climate change was found to be large, with large gross changes in distribution of plant functional types and comparatively smaller changes in net carbon sequestration potential for the region. However, the transient response was found to be on the order of centuries, and to depend strongly on disturbance rates and dispersal distances. Future work should explore the impact of species-specific disturbance and dispersal rates, landscape fragmentation, and other processes that influence migration rates and have been simulated at the sub-continent scale, but now at continental scales, and explore a range of alternative future climate scenarios as they continue to be developed.

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Objective: We identify drinking styles that place teensat greatest risk of later alcohol use disorders (AUD).Design: Population-based cohort study.Setting: Victoria, Australia.

Participants: A representative sample of 1943adolescents living in Victoria in 1992.Outcome measures: Teen drinking was assessed at6 monthly intervals (5 waves) between mean ages 14.9and 17.4 years and summarised across waves as none,one, or two or more waves of: (1) frequent drinking(3+ days in the past week), (2) loss of control overdrinking (difficulty stopping, amnesia), (3) bingedrinking (5+ standard drinks in a day) and (4) heavybinge drinking (20+ and 11+ standard drinks in a dayfor males and females, respectively). Young AdultAlcohol Use Disorder (AUD) was assessed at 3 yearlyintervals (3 waves) across the 20s (mean ages 20.7through 29.1 years).

Results: We show that patterns of teen drinkingcharacterised by loss of control increase risk for AUDacross young adulthood: loss of control over drinking(one wave OR 1.4, 95% CI 1.1 to 1.8; two or morewaves OR 1.9, CI 1.4 to 2.7); binge drinking (one waveOR 1.7, CI 1.3 to 2.3; two or more waves OR 2.0, CI1.5 to 2.6), and heavy binge drinking (one wave OR2.0, CI 1.4 to 2.8; two or more waves OR 2.3, CI 1.6 to3.4). This is not so for frequent drinking, which wasunrelated to later AUD. Although drinking was morecommon in males, there was no evidence of sexdifferences in risk relationships.

Conclusions: Our results extend previous work byshowing that patterns of drinking that represent loss ofcontrol over alcohol consumption (however expressed)are important targets for intervention. In addition tocurrent policies that may reduce overall consumption,emphasising prevention of more extreme teenagebouts of alcohol consumption appears warranted.

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Adolescent depressed mood is related to the development of subsequent mental health problems, and family problems have been linked to adolescent depression. Longitudinal research on adolescent depressed mood is needed to establish the unique impact of family problems independent of other potential drivers. This study tested the extent to which family conflict exacerbates depressed mood during adolescence, independent of changes in depressed mood over time, academic performance, bullying victimization, negative cognitive style, and gender. Students (13 years old) participated in a three-wave bi-national study (n = 961 from the State of Washington, United States, n = 981 from Victoria, Australia; 98 % retention, 51 % female in each sample). The model was cross-lagged and controlled for the autocorrelation of depressed mood, negative cognitive style, academic failure, and bullying victimization. Family conflict partially predicted changes in depressed mood independent of changes in depressed mood over time and the other controls. There was also evidence that family conflict and adolescent depressed mood are reciprocally related over time. The findings were closely replicated across the two samples. The study identifies potential points of intervention to interrupt the progression of depressed mood in early to middle adolescence.

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Annually, the association publishes a journal, The Proceedings, which consists of papers presented at the annual meeting. Robert C. Winthrop: Conservative Opponent of Lincoln by Robert J. Moore The New Cambridge Modern History: A Comment by John M. Roberts South Carolina Ratifies the Federal Constitution by George C. Rogers, Jr. Tillman and the South Carolina Dispensary by Jack E. Tuttle The Place of History in a Liberal Arts Curriculum by Charles S. Davis

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Annually, the association publishes a journal, The Proceedings, which consists of papers presented at the annual meeting. Robert C. Winthrop: Conservative Opponent of Lincoln by Robert J. Moore The New Cambridge Modern History: A Comment by John M. Roberts South Carolina Ratifies the Federal Constitution by George C. Rogers, Jr. Tillman and the South Carolina Dispensary by Jack E. Tuttle The Place of History in a Liberal Arts Curriculum by Charles S. Davis

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Annually, the association publishes a journal, The Proceedings, which consists of papers presented at the annual meeting. Wade Hampton and the Rise of One Party Radical Orthodoxy in South Carolina by Richard Mark Gergel Governor Chamberlain and the End of Reconstruction by Robert J. Moore The Calhoun Papers Project: One Editor’s Valedictory (An Address to the South Carolina Historical Association, April 2, 1977) by W. Edwin Hemphill The Laurens Paper — Half-Way by George C. Rodgers, Jr. Fateful Legacy: White Southerners and the Dilemma of Emancipation by Dan T. Carter The South Carolina Bangers: A Forgotten Loyalist Regiment by Robert D. Bass

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La perspectiva de los conocimientos situados es una postura epistemológica que surge de la corriente feminista y permite comprender las experiencias y la construcción de significados de un sujeto desde la posición que ocupa dentro de un contexto espe­fico. Esta perspectiva no pretende generar un conocimiento generalizable, más bien busca comprender una realidad particular que viven las personas frente a problemáticas espe­ficas. Esta perspectiva se implementó en este trabajo de grado con el objetivo de entender el significado que tiene para un cuidador informal cuidar a una persona con un diagnóstico de esquizofrenia. Este trabajo utilizó una metodología fenomenológica desde la cual se realizaron cinco entrevistas en profundidad al mismo número de cuidadores de personas con esquizofrenia donde se busca indagar acerca de la experiencia del cuidador en relación con su rol, las circunstancias por las se llega a ser cuidador, las condiciones bajo las cuales se da el cuidado, la percepción de la salud de los cuidadores y las expectativas de estas personas. La información se registró por medio de audio y de manera escrita. El análisis de la información se realizó de forma manual teniendo en cuenta a los autores Bautista (2011); Giraldo y González (2015) y Fernández (2006). Inicialmente se generaron categorías orientadoras que se fundamentaron a partir de la teoría y posteriormente se realizó la construcción de categorías emergentes. Acto seguido se contrastaron ambos tipos de categorías (teóricas y empíricas) para reflexionar acerca de la experiencia y construcción de significados de los cuidadores de personas con esquizofrenia. Se identifi³ que la experiencia de las cuidadoras está enmarcada en relación con el género femenino el cual ha asumido tradicionalmente esta función y también es característica que termina justificando el rol que asumen.

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Esta tesis se presenta como el inicio de una larga reflexión que se pregunta por los espacios de trabajo, sus significados, las relaciones y decisiones que los configuran y a la vez ellos configuran, y la manera como se transforman, transgreden y superan a través de la adopción de las tecnologías. Los resultados que aquí se presentan parten del análisis de once (11) organizaciones ubicadas en Bogotá que acompañé durante el 2014 y 2015 en sus procesos de cambio de oficina.

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Unambiguous evidence for the engagement of CF3 group in N-H center dot center dot center dot F-C hydrogen bond in a low polarity solvent, the first observation of its kind, is reported. The presence of such weak molecular interactions in the solution state is convincingly established by one and two-dimensional H-1, F-19, and natural abundant N-15 NMR spectroscopic studies. The strong and direct evidence is derived by the observation of through-space couplings, such as, (1h)J(FH), (1h)J(FN), and (2h)J(FF), where the spin polarization is transmitted through hydrogen bond. In an interesting example of a molecule containing two CF3 groups getting simultaneously involved in hydrogen bond, where hydrogen bond mediated couplings are not reflected in the NMR spectrum, F-19-F-19 NOESY experiment yielded confirmatory evidence. Significant deviations in the strengths of (1)J(NH), variable temperature, and the solvent induced perturbations yielded additional support. The NMR results are corroborated by both DFT calculations and MD simulations, where the quantitative information on different ways of involvement of fluorine in two and three centered hydrogen bonds, their percentage of occurrences, and geometries have been obtained. The hydrogen bond interaction energies have also been calculated.

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The Genesis mission Solar Wind Concentrator was built to enhance fluences of solar wind by an average of 20x over the 2.3 years that the mission exposed substrates to the solar wind. The Concentrator targets survived the hard landing upon return to Earth and were used to determine the isotopic composition of solar-wind—and hence solar—oxygen and nitrogen. Here we report on the flight operation of the instrument and on simulations of its performance. Concentration and fractionation patterns obtained from simulations are given for He, Li, N, O, Ne, Mg, Si, S, and Ar in SiC targets, and are compared with measured concentrations and isotope ratios for the noble gases. Carbon is also modeled for a Si target. Predicted differences in instrumental fractionation between elements are discussed. Additionally, as the Concentrator was designed only for ions ≤22 AMU, implications of analyzing elements as heavy as argon are discussed. Post-flight simulations of instrumental fractionation as a function of radial position on the targets incorporate solar-wind velocity and angular distributions measured in flight, and predict fractionation patterns for various elements and isotopes of interest. A tighter angular distribution, mostly due to better spacecraft spin stability than assumed in pre-flight modeling, results in a steeper isotopic fractionation gradient between the center and the perimeter of the targets. Using the distribution of solar-wind velocities encountered during flight, which are higher than those used in pre-flight modeling, results in elemental abundance patterns slightly less peaked at the center. Mean fractionations trend with atomic mass, with differences relative to the measured isotopes of neon of +4.1±0.9 ‰/amu for Li, between -0.4 and +2.8 ‰/amu for C, +1.9±0.7‰/amu for N, +1.3±0.4 ‰/amu for O, -7.5±0.4 ‰/amu for Mg, -8.9±0.6 ‰/amu for Si, and -22.0±0.7 ‰/amu for S (uncertainties reflect Monte Carlo statistics). The slopes of the fractionation trends depend to first order only on the relative differential mass ratio, Δ m/ m. This article and a companion paper (Reisenfeld et al. 2012, this issue) provide post-flight information necessary for the analysis of the Genesis solar wind samples, and thus serve to complement the Space Science Review volume, The Genesis Mission (v. 105, 2003).