22,313 research outputs found
Office of Spaceflight Standard Spaceborne Global Positioning System (GPS) user equipment project
The Global Positioning System (GPS) provides the following: (1) position and velocity determination to support vehicle GN&C, precise orbit determination, and payload pointing; (2) time reference to support onboard timing systems and data time tagging; (3) relative position and velocity determination to support cooperative vehicle tracking; and (4) attitude determination to support vehicle attitude control and payload pointing
Office of Space Flight standard spaceborne Global Positioning System user equipment project
The Global Positioning System (GPS) provides users autonomous, real-time navigation capability. A vehicle equipped with GPS user equipment can receive and process signals transmitted by a constellation of GPS satellites and derive from the resulting measurements the vehicle's position and velocity. Specified accuracies range from 16 to 76 meters and 0.1 to 1.0 meters/second for position and velocity, respectively. In a rendezvous and docking scenario, the use of a technique called relative GPS can provide range and range rate accuracies on the order of 1 meter and 0.01 meters/second, respectively. Relative GPS requires both vehicles to be equipped with GPS user equipment and a data communication link for transmission of GPS data and GPS satellite selection coordination information. Through coordinated satellite selection, GPS measurement errors common to both users are cancelled and improved relative position and velocity accuracies are achieved. The background, the design approach, the expected performance and capabilities, the development plan, and the project status are described. In addition, a description of relative GPS, the possible GPS hardware and software configurations, and its application to automated rendezvous and capture are presented
A bibliography of six years (1951-1956) research in arithmetic
Thesis (Ed.M.)--Boston Universit
Charge environments around phosphorylation sites in proteins
Background: Phosphorylation is a central feature in many biological processes. Structural analyses
have identified the importance of charge-charge interactions, for example mediating
phosphorylation-driven allosteric change and protein binding to phosphopeptides. Here, we
examine computationally the prevalence of charge stabilisation around phosphorylated sites in the
structural database, through comparison with locations that are not phosphorylated in the same
structures.
Results: A significant fraction of phosphorylated sites appear to be electrostatically stabilised,
largely through interaction with sidechains. Some examples of stabilisation across a subunit
interface are evident from calculations with biological units. When considering the immediately
surrounding environment, in many cases favourable interactions are only apparent after
conformational change that accompanies phosphorylation. A simple calculation of potential
interactions at longer-range, applied to non-phosphorylated structures, recovers the separation
exhibited by phosphorylated structures. In a study of sites in the Phospho.ELM dataset, for which
structural annotation is provided by non-phosphorylated proteins, there is little separation of the
known phospho-acceptor sites relative to background, even using the wider interaction radius.
However, there are differences in the distributions of patch polarity for acceptor and background
sites in the Phospho.ELM dataset.
Conclusion: In this study, an easy to implement procedure is developed that could contribute to
the identification of phospho-acceptor sites associated with charge-charge interactions and
conformational change. Since the method gives information about potential anchoring interactions
subsequent to phosphorylation, it could be combined with simulations that probe conformational
change. Our analysis of the Phospho.ELM dataset also shows evidence for mediation of
phosphorylation effects through (i) conformational change associated with making a solvent
inaccessible phospho-acceptor site accessible, and (ii) modulation of protein-protein interactions
Shape maps for second order partial differential equations
We analyse the singularity formation of congruences of solutions of systems
of second order PDEs via the construction of \emph{shape maps}. The trace of
such maps represents a congruence volume whose collapse we study through an
appropriate evolution equation, akin to Raychaudhuri's equation. We develop the
necessary geometric framework on a suitable jet space in which the shape maps
appear naturally associated with certain linear connections. Explicit
computations are given, along with a nontrivial example
Evaluation of commercial utility of ERTS-A imagery in structural reconnaissance for minerals and petroleum
Five areas in North America (North Slope-Alaska, Superior Province-Canada, Williston Basin-Montana, Colorado and New Mexico-West Texas) are being studied for discernibility of geological evidence on ERTS-1 imagery, Evidence mapped is compared with known mineral/hydrocarbon accumulations to determine the value of the imagery in commercial exploration programs. Evaluation has proceeded in the New Mexico-West Texas area while awaiting imagery in the other areas. To date, results have been better than expected. Clearly discernible structural lineaments in New Mexico-West Texas are evident on the photographs. Comparison of this evidence with known major mining localities in New Mexico indicates a clear pattern of coincidence between the lineaments and mining localities. In West Texas, lineament and geomorphological evidence obtainable from the photographs define the petroleum-productive Central Basin Platform. Based on evaluation results in the New Mexico-West Texas area and on cursory results in the other four areas of North America, ERTS-1 imagery will be extremely valuable in defining the regional and local structure in any commercial exploration program
The Therapeutic Bond Scales: Psychometric Characteristics and Relationship to Treatment Effectiveness
The Therapeutic Bond Scales assess the quality of the therapeutic relationship from the patient\u27s perspective. The therapeutic bond is composed of 3 aspects: working alliance, empathic resonance, and mutual affirmation. Scales were developed to measure these aspects and the therapeutic bond as a whole. The correlations between these scales and 2 measures of outcome (session quality assessed by the patient and termination outcome evaluated by nonparticipant raters) were examined. All scales were significantly correlated with session quality. Therapeutic bond was significantly correlated with termination outcome in both a linear and a curvilinear fashion, suggesting that, at least in the initial phase of therapy, the therapeutic bond can be too high as well as too low
An Economic Evaluation of a Pest Management Control Program: "Outfox the Fox"
Foxes are regarded as a serious pest of environmental and grazing systems in Australia. The fox is a recognised predator of native wildlife and has been a significant contributor to the population decline of many native mammal, bird and reptile species. There are also claims that foxes may account for up to 30% of lamb mortalities in some areas, while mortality due to predation of 2 to 5% is more likely in most regions. The ‘Outfox the Fox’ program was established by NSW Agriculture in conjunction with a number of Rural Land Protection Boards to achieve a more strategic and coordinated fox baiting program. This program relies on a community driven and integrated management approach to the problem. The main features are to synchronise baiting across landholders at least twice a year, undertake baiting during periods when the fox is most susceptible, regularly check and replace baits, and continue until the bait take declines. A stochastic economic surplus and benefit-cost analysis model was developed to evaluate this program. The change in annual economic surplus due to the ‘Outfox the Fox’ program was 9.8m and a mean benefit-cost ratio of 13.0:1. The stochastic analysis indicated that there was a very low probability of this program providing a negative economic return.benefit cost analysis, research evaluation, economic surplus, fox, Farm Management, Land Economics/Use, Livestock Production/Industries, Production Economics, Research and Development/Tech Change/Emerging Technologies, Q160,
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