14,672 research outputs found
A space transportation system operations model
Presented is a description of a computer program which permits assessment of the operational support requirements of space transportation systems functioning in both a ground- and space-based environment. The scenario depicted provides for the delivery of payloads from Earth to a space station and beyond using upper stages based at the station. Model results are scenario dependent and rely on the input definitions of delivery requirements, task times, and available resources. Output is in terms of flight rate capabilities, resource requirements, and facility utilization. A general program description, program listing, input requirements, and sample output are included
PLANNING SOLAR HEATING FOR POULTRY - A LINEAR PROGRAMMING APPROACH
Livestock Production/Industries,
Synchronous collaborative information retrieval: techniques and evaluation
Synchronous Collaborative Information Retrieval refers to
systems that support multiple users searching together at the same time in order to satisfy a shared information need. To date most SCIR systems have focussed on providing various awareness tools in order to enable collaborating users to coordinate the search task. However, requiring users to both search and coordinate the group activity may prove too demanding. On the other hand without effective coordination policies the group search may not be effective. In this paper we propose and evaluate novel system-mediated techniques for coordinating a group search. These techniques allow for an effective division of labour across the group whereby each group member can explore a subset of the search space.We also propose and evaluate techniques to support automated sharing of knowledge across searchers in SCIR, through novel collaborative and complementary relevance feedback techniques. In order to evaluate these techniques, we propose a framework for SCIR evaluation based on simulations. To populate these simulations we extract data from TREC interactive search logs. This work represent the first simulations of SCIR to date and the first such use of this TREC data
Anomaly Detection in Paleoclimate Records using Permutation Entropy
Permutation entropy techniques can be useful in identifying anomalies in
paleoclimate data records, including noise, outliers, and post-processing
issues. We demonstrate this using weighted and unweighted permutation entropy
of water-isotope records in a deep polar ice core. In one region of these
isotope records, our previous calculations revealed an abrupt change in the
complexity of the traces: specifically, in the amount of new information that
appeared at every time step. We conjectured that this effect was due to noise
introduced by an older laboratory instrument. In this paper, we validate that
conjecture by re-analyzing a section of the ice core using a more-advanced
version of the laboratory instrument. The anomalous noise levels are absent
from the permutation entropy traces of the new data. In other sections of the
core, we show that permutation entropy techniques can be used to identify
anomalies in the raw data that are not associated with climatic or
glaciological processes, but rather effects occurring during field work,
laboratory analysis, or data post-processing. These examples make it clear that
permutation entropy is a useful forensic tool for identifying sections of data
that require targeted re-analysis---and can even be useful in guiding that
analysis.Comment: 15 pages, 7 figure
Supporting the 'Sharing Institution' - Practical Steps Towards a More Open Teaching and Learning Culture
4th International Conference on Open RepositoriesThis presentation was part of the session : Conference PresentationsDate: 2009-05-19 03:00 PM – 04:30 PMInstitutional repositories for research output have developed progressively over the last few years. Although a primary motivation is Open Access both institutional and academic needs must also be met in order to foster this spirit effectively. There is now a greater emphasis on creating a more open culture for teaching and learning and institutions are again beginning to play their part more readily. On a larger scale, there are pioneering global examples of courses being preserved and complex learning materials being deposited in national and international databases. But what does fostering a more open culture in the practice of teaching mean for the institution itself and its academics? The virtual learning environment has given greater opportunities for effective administration of courses but in other ways it has had the opposite effect on sharing and re-use. There is potential for institutional solutions which are complementary to the global landscape. In this paper we report on the practical experiences and issues met, in setting up a institutional resource, EdShare, as a vehicle for sharing educational materials more easily in a multi-disciplinary institution. With constructive feedback from faculty, within the EdSpace project, EdShare has migrated into a more visual, web 2.0 style, resource with a flexible deposit process promoting 'micro-sharing'. It now offers a range of sharing options to support the teaching workflow in an encouraging atmosphere. Other features will support the growing emphasis on multidisciplinary teaching and collaboration - both internally and externally.JIS
Cigarette smoking in young adults: the influence of the HTR2A T102C polymorphism and punishment sensitivity
Background: The C allele of a common polymorphism of the serotonin 2A receptor (HTR2A) gene, T102C, results in reduced synthesis of 5-HT2A receptors and has been associated with current smoking status in adults. The -1438A/G polymorphism, located in the regulatory region of this gene, is in linkage disequilibrium with T102C, and the A allele is associated with increased promoter activity and with smoking in adult males. We investigated the contributions of the HTR2A gene, chronic psychological stress, and impulsivity to the prediction of cigarette smoking status and dependence in young adults. Methods: T102C and -1438A/G genotyping was conducted on 132 healthy Caucasian young adults (47 smokers) who completed self-report measures of chronic stress, depressive symptoms, impulsive personality and cigarette use. Results: A logistic regression analysis of current cigarette smoker user status, after adjusting for gender, depressive symptom severity and chronic stress, indicated that the T102C TT genotype relative to the CC genotype (OR = 7.53), and lower punishment sensitivity (OR = 0.91) were each significant predictive risk factors. However, for number of cigarettes smoked, only lower punishment sensitivity was a significant predictor (OR = 0.81). Conclusions: These data indicate the importance of the T102C polymorphism to tobacco use but not number of cigarettes smoked for Caucasian young adults. Future studies should examine whether this is explained by effects of nicotine on the serotonin system. Lower punishment sensitivity increased risk of both smoking and of greater consumption, perhaps via a reduced sensitivity to cigarette health warnings and negative physiological effects
The Boundary Cosmological Constant in Stable 2D Quantum Gravity
We study further the r\^ole of the boundary operator \O_B for macroscopic
loop length in the stable definition of 2D quantum gravity provided by the
formulation. The KdV flows are supplemented by an additional
flow with respect to the boundary cosmological constant . We
numerically study these flows for the , and models, solving for
the string susceptibility in the presence of \O_B for arbitrary coupling
. The spectrum of the Hamiltonian of the loop quantum mechanics is
continuous and bounded from below by . For large positive , the
theory is dominated by the `universal' topological phase present only in
the formulation. For large negative , the
non--perturbative physics approaches that of the definition, although
there is no path to the unstable solutions of the -even models.Comment: (Plain Tex, 11pp, 4 figures available on request) SHEP 91/92-2
COMPTEL neutron response at 17 MeV
The Compton imaging telescope (COMPTEL) instrument of the Gamma Ray Observatory was exposed to 17 MeV d,t neutrons prior to launch. These data were analyzed and compared with Monte Carlo calculations using the MCNP(LANL) code. Energy and angular resolutions are compared and absolute efficiencies are calculated at 0 and 30 degrees incident angle. The COMPTEL neutron responses at 17 MeV and higher energies are needed to understand solar flare neutron data
Gout in a 15-year-old boy with juvenile idiopathic arthritis: A case study
Joint pain is a common complaint in pediatrics and is most often attributed to overuse or injury. In the face of persistent, severe, or recurrent symptoms, the differential typically expands to include bony or structural causes versus rheumatologic conditions. Rarely, a child has two distinct causes for joint pain. In this case, an obese 15-year-old male was diagnosed with gout, a disease common in adults but virtually ignored in the field of pediatrics. The presence of juvenile idiopathic arthritis (JIA) complicated and delayed the consideration of this second diagnosis. Indeed, the absence of gout from this patient’s differential diagnosis resulted in a greater than two-year delay in receiving treatment. The patients’ BMI was 47.4, and he was also mis-diagnosed with osteochondritis dissecans and underwent medical treatment for JIA, assorted imaging studies, and multiple surgical procedures before the key history of increased pain with red meat ingestion, noticed by the patient, and a subsequent elevated uric acid confirmed his ultimate diagnosis. With the increased prevalence of obesity in the adolescent population, the diagnosis of gout should be an important consideration in the differential diagnosis for an arthritic joint in an overweight patient, regardless of age
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