2,487 research outputs found
Feasibility Study of SDAS Instrumentation's Ability to Identify Mobile Launcher (ML)/Crawler-Transporter (CT) Modes During Rollout Operations
The Space Launch System (SLS) and its Mobile Launcher (ML) will be transported to the launch pad via the Crawler-Transporter (CT) system. Rollout (i.e., transportation) loads produce structural loads on the integrated SLS/Orion Multi-Purpose Crew Vehicle (MPCV) launch vehicle which are of a concern with respect to fatigue. As part of the risk reduction process and in addition to the modal building block test approach that has been adopted by the SLS Program, acceleration data will be obtained during rollout for use in modal parameter estimation. There are several occurrences where the ML/CT will be transported either into the Vertical Assembly Building (VAB) or to the launch pad and back without the SLS stack as part of the Kennedy Space Center (KSC) Exploration Ground Systems (EGS) Integrated Test and Checkout (ITCO). NASA KSC EGS has instrumentation installed on both the ML and CT to record data during rollout, at the launch pad, and during liftoff. The EGS instrumentation on the ML, which includes accelerometers, is referred to as the Sensor Data Acquisition System (SDAS). The EGS instrumentation on the CT, which also includes accelerometers, is referred to as the CT Data Acquisition System (CTDAS). The forces and accelerations applied to the ML and CT during a rollout event will be higher than any of the planned building block modal tests. This can be very beneficial in helping identify nonlinear behavior in the structure. Developing modal parameters from the same test hardware in multiple boundary conditions and under multiple levels of excitation is a key step in developing a well correlated FEM. The purpose of this study was three fold. First, determine the target modes of the ML/CT in its rollout configuration. Second, determine if the test degrees of freedom (DOF) corresponding to the layout of the SDAS/CTDAS accelerometers (i.e. position and orientation) is sufficient to identify the target modes. Third, determine if the Generic Rollout Forcing Functions (GRFF's) is sufficient for identifying the ML/CT target modes accounting for variations in CT speed, modal damping, and sensor/ambient background noise levels. The finding from the first part of this study identified 28 target modes of the ML/CT rollout configuration based upon Modal Effective Mass Fractions (MEFF) and engineering judgement. The finding from the second part of this study showed that the SDAS/CTDAS accelerometers (i.e. position and orientation) are able to identify a sufficient number of the target modes to support model correlation of the ML/CT FEM. The finding from the third part of this study confirms the GRFFs sufficiently excite the ML/CT such that varying quantities of the defined target modes should be able to be extracted when utilizing an Experimental Modal Analysis (EMA) Multi-Input Multi-Output (MIMO) analysis approach. An EMA analysis approach was used because Operational Modal Analysis (OMA) tools were not available and the GRFFs were sufficiently uncorrelated. Two key findings from this third part of the study are that the CT speed does not show a significant impact on the ability to extract the modal parameters and that keeping the ambient background noise observed at each accelerometer location at or below 30 grms is essential to the success of this approach
The Effelsberg-Bonn HI Survey (EBHIS)
The new L-band 7-feed-array at the 100-m telescope in Effelsberg will be used
to perform an unbiased fully sampled HI survey of the entire northern
hemisphere observing the galactic and extragalactic sky using simultaneously
two different backends.
The survey will be extremely valuable for a broad range of research topics:
study of the low-mass end of the HI mass function (HIMF) in the local volume,
environmental and evolutionary effects (as seen in the HIMF), the search for
galaxies near low-redshift Lyman-alpha absorbers, and analysis of multiphase
and extraplanar gas, HI shells, and ultra-compact high-velocity-clouds.Comment: 2 pages, 1 figure, to appear in proceeding of "Galaxies in the Local
Volume" Sydney 8-13 July 200
Racionalidades campesinas en los Andes del Sur : reflexiones en torno al cultivo de la quinua y otros vegetales andinos
International audienceThis book originated in a workshop organised in La Paz (Bolivia) in December 2008, as part of the Franco-Bolivian ANR-EQUECO programme, with the aim of reflecting on socio-environmental changes in agriculture in the southern Andes over the last 1,000 years. Subsequently, as a result of international collaborations, including the Franco-Argentine ECOS programme, the editors invited other experts to contribute their work to these reflections. The authors of this book - archaeologists, anthropologists, geographers, geneticists, agronomists and ecologists - represent a balanced panel of human and biophysical sciences. All have direct and recent experience of the current or past reality of the societies and natural environment of the Southern Andes. Despite the diversity of their respective disciplines and perspectives, the authors have endeavoured to make their contributions accessible to a non-specialist audience, presenting tables and figures to facilitate understanding of the data and using a glossary to define, where necessary, certain technical or vernacular terms. The temporal scope of the book covers pre-Hispanic periods to the present, while geographically, it covers the southern altiplano and inter-Andean valleys of southern Bolivia, the puna and valleys of northwestern Argentina, and the contrasting regions of Chile.Este libro tuvo su origen en un taller cuyo objetivo fue reflexionar sobre los cambios socio ambientales en la agricultura del sur andino en los últimos 1.000 años, encuentro organizado en La Paz (Bolivia) en diciembre de 2008, en el marco del programa franco-boliviano EQUECO. Luego, como fruto de colaboraciones internacionales entre ellas el programa franco-argentino ECOS, los editores invitaron a otros expertos más para que aporten con sus trabajos a estas reflexiones.Los autores de este libro –arqueólogos, antropólogos, geógrafos, genetistas, agrónomos y ecólogos– representan un panel equilibradoentre ciencias humanas y biofísicas. Todos cuentan con una experiencia directa y reciente de la realidad actual o pasada de las sociedades y del ambiente natural de los Andes del Sur. A pesar de la diversidad de sus respectivas disciplinas y perspectivas, los autores se aplicaron en hacer sus contribuciones accesibles al público no especializado, presentando tablas y figuras que faciliten la comprensión de los datos y utilizando un glosario para definir, cuando necesario, ciertos términos técnicos o vernaculares. El alcance temporal del libro cubre desde los períodos prehispánicos hasta el presente mientras que en lo geográfico, recorre desde el altiplano sur y los valles interandinos del sur de Bolivia, hasta la puna y los valles del noroeste de Argentina pasando por las contrastadas regiones de Chile
The route and timing of hydrogen sulfide therapy critically impacts intestinal recovery following ischemia and reperfusion injury
PURPOSE:
Hydrogen sulfide (H2S) has many beneficial properties and may serve as a novel treatment in patients suffering from intestinal ischemia-reperfusion injury (I/R). The purpose of this study was to examine the method of delivery and timing of administration of H2S for intestinal therapy during ischemic injury. We hypothesized that 1) route of administration of hydrogen sulfide would impact intestinal recovery following acute mesenteric ischemia and 2) preischemic H2S conditioning using the optimal mode of administration as determined above would provide superior protection compared to postischemic application.
METHODS:
Male C57BL/6J mice underwent intestinal ischemia by temporary occlusion of the superior mesenteric artery. Following ischemia, animals were treated according to one of the following (N=6 per group): intraperitoneal or intravenous injection of GYY4137 (H2S-releasing donor, 50mg/kg in PBS), vehicle, inhalation of oxygen only, inhalation of 80ppm hydrogen sulfide gas. Following 24-h recovery, perfusion was assessed via laser Doppler imaging, and animals were euthanized. Perfusion and histology data were assessed, and terminal ileum samples were analyzed for cytokine production following ischemia. Once the optimal route of administration was determined, preischemic conditioning with H2S was undertaken using that route of administration. All data were analyzed using Mann-Whitney. P-values <0.05 were significant.
RESULTS:
Mesenteric perfusion following intestinal I/R was superior in mice treated with intraperitoneal (IP) GYY4137 (IP vehicle: 25.6±6.0 vs. IP GYY4137: 79.7±15.1; p=0.02) or intravenous (IV) GYY4137 (IV vehicle: 36.3±5.9 vs. IV GYY4137: 100.7±34.0; p=0.03). This benefit was not observed with inhaled H2S gas (O2 vehicle: 66.6±11.4 vs. H2S gas: 81.8±6.0; p=0.31). However, histological architecture was only preserved with intraperitoneal administration of GYY4127 (IP vehicle: 3.4±0.4 vs. IP GYY4137: 2±0.3; p=0.02). Additionally, IP GYY4137 allowed for significant attenuation of inflammatory chemokine production of IL-6, IP-10 and MIP-2. We then analyzed whether there was a difference between pre- and postischemic administration of IP GYY4137. We found that preconditioning of animals with intraperitoneal GYY4137 only added minor improvements in outcomes compared to postischemic application.
CONCLUSION:
Therapeutic benefits of H2S are superior with intraperitoneal application of an H2S donor compared to other administration routes. Additionally, while intraperitoneal treatment in both the pre- and postischemic period is beneficial, preischemic application of an H2S donor was found to be slightly better. Further studies are needed to examine long term outcomes and further mechanisms of action prior to widespread clinical application.
TYPE OF STUDY:
Basic science.
LEVEL OF EVIDENCE:
N/A
The Effelsberg-Bonn HI Survey: Data reduction
Starting in winter 2008/2009 an L-band 7-Feed-Array receiver is used for a
21-cm line survey performed with the 100-m telescope, the Effelsberg-Bonn HI
survey (EBHIS). The EBHIS will cover the whole northern hemisphere for decl.>-5
deg comprising both the galactic and extragalactic sky out to a distance of
about 230 Mpc. Using state-of-the-art FPGA-based digital fast Fourier transform
spectrometers, superior in dynamic range and temporal resolution to
conventional correlators, allows us to apply sophisticated radio frequency
interference (RFI) mitigation schemes.
In this paper, the EBHIS data reduction package and first results are
presented. The reduction software consists of RFI detection schemes, flux and
gain-curve calibration, stray-radiation removal, baseline fitting, and finally
the gridding to produce data cubes. The whole software chain is successfully
tested using multi-feed data toward many smaller test fields (1--100 square
degrees) and recently applied for the first time to data of two large sky
areas, each covering about 2000 square degrees. The first large area is toward
the northern galactic pole and the second one toward the northern tip of the
Magellanic Leading Arm. Here, we demonstrate the data quality of EBHIS Milky
Way data and give a first impression on the first data release in 2011.Comment: 17 pages, 14 figures; to be published in ApJ
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