771 research outputs found

    Navigation and flight director guidance for the NASA/FAA helicopter MLS curved approach flight test program

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    The navigation and flight director guidance systems implemented in the NASA/FAA helicopter microwave landing system (MLS) curved approach flight test program is described. Flight test were conducted at the U.S. Navy's Crows Landing facility, using the NASA Ames UH-lH helicopter equipped with the V/STOLAND avionics system. The purpose of these tests was to investigate the feasibility of flying complex, curved and descending approaches to a landing using MLS flight director guidance. A description of the navigation aids used, the avionics system, cockpit instrumentation and on-board navigation equipment used for the flight test is provided. Three generic reference flight paths were developed and flown during the test. They were as follows: U-Turn, S-turn and Straight-In flight profiles. These profiles and their geometries are described in detail. A 3-cue flight director was implemented on the helicopter. A description of the formulation and implementation of the flight director laws is also presented. Performance data and analysis is presented for one pilot conducting the flight director approaches

    Research on new techniques for the analysis of manual control systems Progress report, 15 Dec. 1968 - 15 Jun. 1969

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    Decision processes of human manual controllers, neuromuscular system, and stochastic processe

    Dihyperon in Chiral Colour Dielectric Model

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    The mass of dihyperon with spin, parity Jπ=0+J^{\pi}=0^{+} and isospin I=0I = 0 is calculated in the framework of Chiral colour dielectric model. The wave function of the dihyperon is expressed as a product of two colour-singlet baryon clusters. Thus the quark wave functions within the cluster are antisymmetric. Appropriate operators are then used to antisymmetrize inter-cluster quark wave functions. The radial part of the quark wavefunctions are obtained by solving the the quark and dielectric field equations of motion obtained in the Colour dielectric model. The mass of the dihyperon is computed by including the colour magnetic energy as well as the energy due to meson interaction. The recoil correction to the dihyperon mass is incorporated by Peierls-Yoccoz technique. We find that the mass of the dihyperon is smaller than the ΛΛ\Lambda-\Lambda threshold by over 100 MeV. The implications of our results on the present day relativistic heavy ion experiments is discussed.Comment: LaTeX, 13 page

    Meson-Baryon Form Factors in Chiral Colour Dielectric Model

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    The renormalised form factors for pseudoscalar meson-baryon coupling are computed in chiral colour dielectric model. This has been done by rearranging the Lippmann-Schwinger series for the meson baryon scattering matrix so that it can be expressed as a baryon pole term with renormalized form factors and baryon masses and the rest of the terms which arise from the crossed diagrams. Thus we are able to obtain an integral equation for the renormalized meson-baryon form factors in terms of the bare form factors as well as an expression for the meson self energy. This integral equation is solved and renormalized meson baryon form factors and renormalized baryon masses are computed. The parameters of the model are adjusted to obtain a best fit to the physical baryon masses. The calculations show that the renormalized form factors are energy-dependent and differ from the bare form factors primarily at momentum transfers smaller than 1 GeV. At nucleon mass, the change in the form factors is about 10% at zero momentum transfer. The computed form factors are soft with the equivalent monopole cut-off mass of about 500 MeV. The renormalized coupling constants are obtained by comparing the chiral colour dielectric model interaction Hamiltonian with the standard form of meson-nucleon interaction Hamiltonian. The ratio of ΔNπ\Delta N\pi and NNπNN\pi coupling constants is found to be about 2.15. This value is very close to the experimental value.Comment: 16 pages, 7 postscript figure

    Can Physician Champions Improve Kangaroo Care? Trends over 5 Years in Rural Western India

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    Introduction: In 2013, approximately 2.8 million children worldwide died within the neonatal period. India is at the epicenter of this tragedy, accounting for one-third of all neonatal mortalities. Prematurity and/or with low birth weight are the leading cause of neonatal mortality and India has the highest number of neonates born preterm and weighing less than 2,500 grams worldwide. It is estimated that Kangaroo Care can avert up to 48% of all neonatal deaths among premature babies by 2025. However, the promise of Kangaroo Care as a low-cost, safe, and efficacious intervention to reduce neonatal mortality in India has not been realized due to suboptimal implementation. Physician champions can improve Kangaroo Care implementation, but the magnitude of their impact is unknown. Methods: A retrospective cohort study of 648 infants identified using clinical data from a NICU located in rural western India. Physicians who led Kangaroo Care training sessions with neonates and coached peer healthcare professionals were considered champions. Two Kangaroo Care champions were on staff full-time from January 2010 through June 2011, part-time from July 2011 through June 2012, and absent thereafter. We examined the effect of the withdrawal of physician champions on overall use using logistic regression, time to initiation using competing risk cox regression, and intensity using linear regression models of the two main components of Kangaroo Care, skin-to-skin care and breastfeeding, separately. Findings: In comparison to when Kangaroo Care champions were present, their absence was associated with a 45% decrease in the odds of receiving skin-to-skin care (95% CI): 64% to 17%), 38% decrease in the rate of initiation of skin-to-skin care (95% CI: 53% to 82%), and on average, 1.47 less hours of skin-to-skin care (95% CI: -2.07 to -0.86). Breastfeeding practices were similar across different champion environments. Interpretation: Withdrawal of Kangaroo Care champions from neonatal intensive care unit in rural western India is associated with diminished administration, delayed initiation, and shorter duration of skin-to-skin care, but did not impact breastfeeding practices. Training healthcare workers and community stakeholders to become champions could help in scaling up and maintaining Kangaroo Care practices. Funding: This research was supported by TL1-TR001454 (to A.S.) from National Center for Advancing Translational Sciences, and P60-MD006912-05 (to J.A.) from National Institute on Minority Health and Disparities. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH

    Luminescence properties of Ti-doped gem-grade zirconia powders

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    A detailed investigation on luminescence properties of gem-grade zirconia (NFC) as a function of Ti doping is presented. The effect of various parameters such as Ti concentration, environment of heat treatment and temperature was studied in detail and the optimum conditions for producing zirconia with luminescence properties comparable to standard material determined

    Critical Analysis of PIM2 Score Applicability in a Tertiary Care PICU in Western India

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    Objective. Children have limited physiological reserve that deteriorates rapidly. Present study profiled patients admitted to PICU and determined PIM2 score applicability in Indian setting. Patients and Methods. Prospective observational study. Results. In 742 consecutive admissions, male : female ratio was 1.5 : 1, 35.6% patients were ventilated, observed mortality was 7%, and 26.4% were <1 year. The profile included septicemia and septic shock (29.6%), anemia (27.1%), pneumonia (19.6%), and meningitis and encephalitis (17.2%). For the first year, sensitivity of PIM2 was 65.8% and specificity was 71% for cutoff value at 1.9 by ROC curve analysis. The area under the curve was 0.724 (95% CI: 0.69, 0.76). This cutoff was validated for second year data yielding similar sensitivity (70.6%) and specificity (65%). Logistic regression analysis (LRA) over entire data revealed various variables independently associated with mortality along with PIM2 score. Another logistic model with same input variables except PIM2 yielded the same significant variables with Nagelkerke R square of 0.388 and correct classification of 78.5 revealing contribution of PIM2 in predicting mortality is meager. Conclusion. Infectious diseases were the commonest cause of PICU admission and mortality. PIM2 scoring did not explain the outcome adequately, suggesting need for recalibration. Following PALS/GEM guidelines was associated with better outcome

    Chiral Symmetry and the Nucleon's Vector Strangeness Form Factors

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    The nucleon's strange-quark vector current form factors are studied from the perspective of chiral symmetry. It is argued that chiral perturbation theory cannot yield a prediction for the strangeness radius and magnetic moment. Arrival at definite predictions requires the introduction of additional, model-dependent assumptions which go beyond the framework of chiral perturbation theory. A variety of such model predictions is surveyed, and the credibility of each is evaluated. The most plausible prediction appears in a model where the unknown chiral counterterms are identified with tt-channel vector meson exchange amplitudes. The corresponding prediction for the mean square Dirac strangeness radius is rs2=0.24\langle r_s^2\rangle = 0.24 fm2^2, which would be observable in up-coming semileptonic determinations of the nucleon's strangeness form factors.Comment: LaTex 31 pages, four figures available from authors

    Working Group Report: Heavy-Ion Physics and Quark-Gluon Plasma

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    This is the report of Heavy Ion Physics and Quark-Gluon Plasma at WHEPP-09 which was part of Working Group-4. Discussion and work on some aspects of Quark-Gluon Plasma believed to have created in heavy-ion collisions and in early universe are reported.Comment: 20 pages, 6 eps figures, Heavy-ion physics and QGP activity report in "IX Workshop on High Energy Physics Phenomenology (WHEPP-09)" held in Institute of Physics, Bhubaneswar, India, during January 3-14, 2006. To be published in PRAMANA - Journal of Physics (Indian Academy of Science
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