9,060 research outputs found

    Planetary/DOD entry technology flight experiments. Volume 1: Executive summary

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    The feasibility of using the space shuttle to launch planetary and DoD entry flight experiments was examined. The results of the program are presented in two parts: (1) simulating outer planet environments during an earth entry test, the prediction of Jovian and earth radiative heating dominated environments, mission strategy, booster performance and entry vehicle design, and (2) the DoD entry test needs for the 1980's, the use of the space shuttle to meet these DoD test needs, modifications of test procedures as pertaining to the space shuttle, modifications to the space shuttle to accommodate DoD test missions and the unique capabilities of the space shuttle. The major findings of this program are summarized

    A new code for Fourier-Legendre analysis of large datasets: first results and a comparison with ring-diagram analysis

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    Fourier-Legendre decomposition (FLD) of solar Doppler imaging data is a promising method to estimate the sub-surface solar meridional flow. FLD is sensible to low-degree oscillation modes and thus has the potential to probe the deep meridional flow. We present a newly developed code to be used for large scale FLD analysis of helioseismic data as provided by the Global Oscillation Network Group (GONG), the Michelson Doppler Imager (MDI) instrument, and the upcoming Helioseismic and Magnetic Imager (HMI) instrument. First results obtained with the new code are qualitatively comparable to those obtained from ring-diagram analyis of the same time series.Comment: 4 pages, 2 figures, 4th HELAS International Conference "Seismological Challenges for Stellar Structure", 1-5 February 2010, Arrecife, Lanzarote (Canary Islands

    Crop-phenology and LANDSAT-based irrigated lands inventory in the high plains

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    Optimal LANDSAT image dates for 1980 were identified based on the weekly crop-weather reports for Colorado, New Mexico, South Dakota, Texas, Oklahoma, Kansas, Nebraska, and Wyoming. The 1979 agricultural statistics data were entered into computer files and a revised questionnaire was developed and mailed to ASCS county agents. A set of computer programs was developed to allow the preparation of computer-assisted graphic displays of much of the collected data

    Crop phenology and LANDSAT-based irrigated lands inventory in the high plains

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    The activity concentrated on identifying crop and irrigation data sources for the eight states within the High Plains Aquifer and making contacts concerning the nature of these data. A mail questionnaire was developed to gather specific data not routinely reported through standard data collection channels. Input/output routines were designed for High Plains crop and irrigation data and initial statistical data on crops were input to computer files

    Molecular cloning of an insect pheromone-binding protein

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    AbstractClones coding for the pheromone binding protein precursor have been selected from a cDNA library derived from antennae of the male moth, Antheraea polyphemus. The deduced protein sequence consists of a signal peptide of 20 amino acid residues and a mature binding protein of 142 amino acid residues. RNA blot hybridization indicated that the mRNA is selectively expressed in the antennae of the male moth.Pheromone binding protein; cDNA cloning; Nucleotide sequence; Primary structure; RNA blot hybridizatio

    Matrix-free calcium in isolated chromaffin vesicles

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    Isolated secretory vesicles from bovine adrenal medulla contain 80 nmol of Ca2+ and 25 nmol of Mg2+ per milligram of protein. As determined with a Ca2+-selective electrode, a further accumulation of about 160 nmol of Ca2+/mg of protein can be attained upon addition of the Ca2+ ionophore A23187. During this process protons are released from the vesicles, in exchange for Ca2+ ions, as indicated by the decrease of the pH in the incubation medium or the release of 9-aminoacridine previously taken up by the vesicles. Intravesicular Mg2+ is not released from the vesicles by A23 187, as determined by atomic emission spectroscopy. In the presence of N H Q , which causes the collapse of the secretory vesicle transmembrane proton gradient (ApH), Ca2+ uptake decreases. Under these conditions A23 187-mediated influx of Ca2+ and efflux of H+ cease at Ca2+ concentrations of about 4 pM. Below this concentration Ca2+ is even released from the vesicles. At the Ca2+ concentration at which no net flux of ions occurs the intravesicular matrix free Ca2+ equals the extravesicular free Ca2+. In the absence of NH4C1 we determined an intravesicular pH of 6.2. Under these conditions the Ca2+ influx ceases around 0.15 pM. From this value and the known pH across the vesicular membrane an intravesicular matrix free Ca2+ concentration of about 24 pM was calculated. This is within the same order of magnitude as the concentration of free Ca2+ in the vesicles determined in the presence of NH4C1. Calculation of the total Ca2+ present in the secretory vesicles gives an apparent intravesicular Ca2+ concentration of 40 mM, which is a factor of lo4 higher than the free intravesicular concentration of Ca2+. It can be concluded, therefore, that the concentration gradient of free Ca2+ across the secretory vesicle membrane in the intact chromaffin cells is probably small, which implies that less energy is required to accumulate and maintain Ca2+ within the vesicles than was previously anticipated

    Interaction Design of Augmented Education Environments - Augmented and Mixed Reality for performance and training support of Aviation / Automotive Technicians.

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    "Augmented reality (AR),Mixed Reality (MR) and their mix and combination with other disruptive technologies offer an enormous potential for supporting instructors and trainees in modern education and working environments such as of aircraft maintenance technicians or automotive service technicians. In this paper we investigate and show some examples on how the performance and training of such instructors and trainees can be actively supported. Furthermore we will discuss the new challenges for training designers. The augmentation of the physical world with interactive, context-aware information (e.g. 2D and 3D content) provides multifaceted possibilities, on various ubiquitous and pervasive computing environments. While there is still the broad opinion that these concepts are just situated in the world of science fiction (SciFi) and SciFi movies, we will relate these techniques to existing technologies and prototypes in research. Terms like outernet, print + or 2.0, augmented goggles, wearable technology are not just remaining pure buzzwords anymore. We will demonstrate how different prototypes applying low cost rapid prototyping methods can be applied as powerful performance assistance and training support instruments, whereby discussing the requirements and user-needs analysis phases as well as human–computer interaction and interaction design issues, user modelling, usability engineering, prototyping and evaluation issues. Different scenarios are possible and provide the basis to generate storyboards. One of the key factors is hereby to analyse typical tasks and activities of users and utilize familiar user interaction paradigms for accessing information, such as using a book or assisting the work with task sheets. For example by augmenting the material that is printed in the book with additional graphical 3D interactive information which can be viewed and manipulated by the instructor and/or trainee, one can provide a link between traditional learning and technology-enhanced learning. Basing on theoretical and empirical research it is possible then to design via first moodboards and scribbles relevant prototypes. A qualitative and quantitative analysis can be used to define a basic design process for such new environments and settings. Moreover, MR and AR along with Mobile Tagging (MT) combined with Pervasive Computing provide the possibility to realize a Physical World Connection (PWC) between Reality and Virtuality. In the field of aviation and automotive industry, this offers manifold possibilities for maintenance and service personnel to get access to assistive technologies in a very intuitive way to enhance their operation, work, training, and knowledge. Assistance for the large variety of job tasks can be provided to a certain extent by offering augmentation of the different senses like vision and audition, providing a media-rich interface. Although the roots of Mixed Reality and Augmented Reality are based on prototype applications in the aircraft industry in the early 1990s, the impact of these emerging technologies on special target groups has not yet been investigated and validated by many research groups. With a specific focus on these user communities, applications are considerably more influenced by both usefulness and usability of technology. Consequently, it is argued that key issues in developing such applications are the tracking methodology, the display technology, interaction (devices and framework) and most of all ensuring good usability. In this paper, a concrete example in a aviation and automotive environment will be presented as a case study for investigating and validating these key issues. Preliminary results of semi-structured interviews and observations in real training and work settings indicate a lack of information concerning existence of such technologies and environments, but show big interest and potential for such educational and workplace innovations, while concrete visions or user requirements for future augmented education environments remain open and are subject of our further research steps

    Theory of Coherent Time-dependent Transport in One-dimensional Multiband Semiconductor Superlattices

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    We present an analytical study of one-dimensional semiconductor superlattices in external electric fields, which may be time-dependent. A number of general results for the (quasi)energies and eigenstates are derived. An equation of motion for the density matrix is obtained for a two-band model, and the properties of the solutions are analyzed. An expression for the current is obtained. Finally, Zener-tunneling in a two-band tight-binding model is considered. The present work gives the background and an extension of the theoretical framework underlying our recent Letter [J. Rotvig {\it et al.}, Phys. Rev. Lett. {\bf 74}, 1831 (1995)], where a set of numerical simulations were presented.Comment: 15 pages, Revtex 3.0, uses epsf, 2 ps figures attache
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