760 research outputs found
Asynchronous transfer mode link performance over ground networks
The results of an experiment to determine the feasibility of using asynchronous transfer mode (ATM) technology to support advanced spacecraft missions that require high-rate ground communications and, in particular, full-motion video are reported. Potential nodes in such a ground network include Deep Space Network (DSN) antenna stations, the Jet Propulsion Laboratory, and a set of national and international end users. The experiment simulated a lunar microrover, lunar lander, the DSN ground communications system, and distributed science users. The users were equipped with video-capable workstations. A key feature was an optical fiber link between two high-performance workstations equipped with ATM interfaces. Video was also transmitted through JPL's institutional network to a user 8 km from the experiment. Variations in video depending on the networks and computers were observed, the results are reported
Explorations With Fixed-Role Therapy
Here then, are the first studies of the effectiveness of fixed role therapy. We hope that making these available, in their original unedited form, to the wider scientific community will fill a gap in the historical record and stimulate further work on this important technique on Kelly\u27s approach to human adaptation.https://scholars.fhsu.edu/fort_hays_studies_series/1047/thumbnail.jp
The Handbook of Clinic Practice
The Handbook of Clinic Practice is a major surviving document that shows Dr. Kelly\u27s early development as a clinician. The Handbook began as a guide for bachelor and master level students working in the Clinc. This was a major teaching tool for Dr. Kelly during his years at Fort Hays Kansas State College. It represents his early position regarding behavior in a clinical setting, and also provides a glimpse of the immense variety and scope of Dr. Kelly\u27s talents.https://scholars.fhsu.edu/fort_hays_studies_series/1048/thumbnail.jp
Sequential Probability Ratio Test for Collision Avoidance Maneuver Decisions Based on a Bank of Norm-Inequality-Constrained Epoch-State Filters
Sequential probability ratio tests explicitly allow decision makers to incorporate false alarm and missed detection risks, and are potentially less sensitive to modeling errors than a procedure that relies solely on a probability of collision threshold. Recent work on constrained Kalman filtering has suggested an approach to formulating such a test for collision avoidance maneuver decisions: a filter bank with two norm-inequality-constrained epoch-state extended Kalman filters. One filter models 1he null hypothesis 1ha1 the miss distance is inside the combined hard body radius at the predicted time of closest approach, and one filter models the alternative hypothesis. The epoch-state filter developed for this method explicitly accounts for any process noise present in the system. The method appears to work well using a realistic example based on an upcoming highly-elliptical orbit formation flying mission
Three hydrophobic amino acids in Escherichia coli HscB make the greatest contribution to the stability of the HscB-IscU complex
<p>Abstract</p> <p>Background</p> <p>General iron-sulfur cluster biosynthesis proceeds through assembly of a transient cluster on IscU followed by its transfer to a recipient apo-protein. The efficiency of the second step is increased by the presence of HscA and HscB, but the reason behind this is poorly understood. To shed light on the function of HscB, we began a study on the nature of its interaction with IscU. Our work suggested that the binding site of IscU is in the C-terminal domain of HscB, and two different triple alanine substitutions ([L92A, M93A, F153A] and [E97A, E100A, E104A]) involving predicted binding site residues had detrimental effects on this interaction. However, the individual contribution of each substitution to the observed effect remains to be determined as well as the possible involvement of other residues in the proposed binding site.</p> <p>Results</p> <p>In the work reported here, we used isothermal titration calorimetry to characterize the affinity of single alanine HscB mutants for IscU, and subsequently confirmed our results with nuclear magnetic resonance spectroscopy. Alanine substitutions of L92, L96, and F153 severely impaired the ability of HscB to form a complex with IscU; substitutions of R87, R99, and E100 had more modest effects; and substitutions of T89, M93, E97, D103, E104, R152, K156, and S160 had only minor or no detectable effects.</p> <p>Conclusions</p> <p>Our results show that the residues of HscB most important for strong interaction with IscU include three hydrophobic residues (L92, L96, and F153); in addition, we identified a number of other residues whose side chains contribute to a lesser extent to the interaction. Our results suggest that the triple alanine substitution at HscB positions 92, 96, and 153 will destabilize the HscB-IscU complex by ΔΔ<it>G</it><sub>b</sub>≅ 5.7 kcal/mol, equivalent to a ≅ 15000-fold reduction in the affinity of HscB for IscU. We propose that this triple mutant could provide a more definitive test of the functional importance of the HscB-IscU interaction in vivo than those used previously that yielded inconclusive results.</p
Unique opportunities for NMR methods in structural genomics
This Perspective, arising from a workshop held in July 2008 in Buffalo NY, provides an overview of the role NMR has played in the United States Protein Structure Initiative (PSI), and a vision of how NMR will contribute to the forthcoming PSI-Biology program. NMR has contributed in key ways to structure production by the PSI, and new methods have been developed which are impacting the broader protein NMR community
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Investigation of the elastic modulus of SSC coils
The Materials Development Laboratory at Fermilab has been conducting experiments on the mechanical properties of superconducting coils. Two of these measurements were designed to measure the elastic modulus of actual SSC coils in an effort to increase the precision of previously reported data. The first experiment utilizes a fixture redesigned for increased stiffness, in an attempt to reduce uncertainty in the data. As in the previous fixture of this type, the inner coil radius has been left unconstrained. The second fixture constrains the coil on all sides, allowing for the determination of the radial and azimuthal components of the cured coil modulus. A finite element model of the first test arrangement was also created to predict the compliance of the fixture, and compare numerical predictions with the experimental data. The results from this fixture suggest that the coil modulus is higher than previously reported, at 1.43{plus_minus}0.03{times}10{sup 10} Pa (2.08{plus_minus}.05{times}10{sup 6} psi). The main difference between the two experiments were the compliance of the fixture, which was found to have been seriously underestimated in last years test. Results from the second fixture suggest a coil modulus of 8.48{plus_minus}0.82{times}10{sup 9} Pa (1.23{plus_minus}0.12{times}10{sup 6} psi) for the azimuthal modulus, and between 8.96{plus_minus}0.822{times}10{sup 9} Pa (1.3{plus_minus}0.12{times}10{sup 6} psi) at lower loads and 1.12{plus_minus}0.24{times}10{sup 10} Pa (1.63{plus_minus}0.35{times}10{sup 6} psi) at higher loads in the radial direction. For a constrained coil, little difference is noted between the radial and azimuthal moduli of the coil. 2 refs., 8 figs
Unique opportunities for NMR methods in structural genomics
This Perspective, arising from a workshop held in July 2008 in Buffalo NY, provides an overview of the role NMR has played in the United States Protein Structure Initiative (PSI), and a vision of how NMR will contribute to the forthcoming PSI-Biology program. NMR has contributed in key ways to structure production by the PSI, and new methods have been developed which are impacting the broader protein NMR community
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