325 research outputs found
Multiplicative Error State Kalman Filter vs Nonlinear Complimentary Filter for a High Performance Aircraft Attitude Estimation
Modern control law designs increasingly use aircraft attitude information to improve aircraft manoeuverability. Attitude information allows for gravity term compensations in the longitudinal as well as lateral directional control laws of a typical fighter aircraft. Methodologies and comparisons of multiplicative error state Kalman filter (MEKF) and nonlinear complimentary filter for estimation of attitudes of a high performance aircraft using its onboard autonomous sensors is presented. Shows a problem in pitch angle estimation beyond ± 80 deg in the MEKF and a solution is proposed for the same for the first time. Also presents novel aiding sensor modelling for the implementation of attitude heading reference system for this class of aircraft for the first time. The filter formulations are evaluated using full range manuoevering real flight test data
To compare the effects of intra vaginal prostaglandin E1 and intra-cervical prostaglandin E2 for prelabour ripening of unfavorable uterine cervix in nulliparous women
Background: Induction of labour by use of prostaglandins improves the obstetric outcome in complicated cases such as prolonged deliveries. The aim of the present study was to compare the effect of prostaglandin E1 (PGE1) and prostaglandin E2 (PGE2) for prelabour ripening of unfavourable uterine cervix in nulliparous women, to study the effect of PGE1 and PGE2 on duration of labor and to evaluate the obstetrical and neonatal outcome of induction of labour using prostaglandins E1 and E2.Methods: This was a prospective study conducted on 50 nulliparous women with singleton pregnancy with gestational age ≥37 weeks during the period from August 2008 to October 2010 in the Department of Obstetrics and Gynaecology of Bombay Hospital Institute of Medical Sciences and Allied Hospitals, Mumbai. All the 50 patients were divided into two groups. Group-1 containing 25 patients received intravaginal PGE1, (Tablet Misoprostol 25 mcg) inserted in the posterior vaginal fornix under all aseptic precautions. Group-2 containing 25 patients received intracervical PGE2, (Dinoprostone gel, 0.5 mg). Analysis and comparison of various parameters like induction- delivery interval, Bishops score before and after administration of drug, mode of delivery, neonatal outcome, foeto-maternal complications between the two groups were noted and analysed the data statistically by using Chi-square, continuity correction, Fisher's exact test and Mann-Whitney tests.Results: Majority of the patients in both the groups were under the age of 23-27 years. Post-datism was the common indication noticed in 18 (72%) and 13 (52%) patients of both the groups respectively. Maximum patients had a Bishop’s score of 3 in PGE1 (56%) and PGE2 groups (48%) respectively. The improvement in Bishop’s score in both the groups before and after drug administration was 6.20 and 6.76 respectively. Maximum patients in both the groups went into active labour within six hours of induction of labour. The most common side effects seen in our study was nausea and vomiting in both groups. Majority (23) were born with Apgar score 8-10 in group 1 and 21 for group 2 patients.Conclusions: Both the drugs had similar efficacy and safety in induction of labour. Prospective research is required to fully evaluate the impact of AMOR-IPAT on nulliparous birth outcomes
Nanoscale Defect Formation on InP(111) Surfaces after MeV Sb Implantation
We have studied the surface modifications as well as the surface roughness of
the InP(111) surfaces after 1.5 MeV Sb ion implantations. Scanning Probe
Microscope (SPM) has been utilized to investigate the ion implanted InP(111)
surfaces. We observe the formation of nanoscale defect structures on the InP
surface. The density, height and size of the nanostructures have been
investigated here as a function of ion fluence. The rms surface roughness, of
the ion implanted InP surfaces, demonstrates two varied behaviors as a function
of Sb ion fluence. Initially, the roughness increases with increasing fluence.
However, after a critical fluence the roughness decreases with increasing
fluence. We have further applied the technique of Raman scattering to
investigate the implantation induced modifications and disorder in InP. Raman
Scattering results demonstrate that at the critical fluence, where the decrease
in surface roughness occurs, InP lattice becomes amorphous.Comment: 18 pages, 9 figure
Site-Specific Effects of PECAM-1 on Atherosclerosis in LDL Receptor-Deficient Mice
Objective—Atherosclerosis is a vascular disease that involves lesion formation at sites of disturbed flow under the influence of genetic and environmental factors. Endothelial expression of adhesion molecules that enable infiltration of immune cells is important for lesion development. Platelet/endothelial cell adhesion molecule-1 (PECAM-1; CD31) is an adhesion and signaling receptor expressed by many cells involved in atherosclerotic lesion development. PECAM-1 transduces signals required for proinflammatory adhesion molecule expression at atherosusceptible sites; thus, it is predicted to be proatherosclerotic. PECAM-1 also inhibits inflammatory responses, on which basis it is predicted to be atheroprotective.
Methods and Results—We evaluated herein the effect of PECAM-1 deficiency on development of atherosclerosis in LDL receptor– deficient mice. We found that PECAM-1 has both proatherosclerotic and atheroprotective effects, but that the former dominate in the inner curvature of the aortic arch whereas the latter dominate in the aortic sinus, branching arteries, and descending aorta. Endothelial cell expression of PECAM-1 was sufficient for its atheroprotective effects in the aortic sinus but not in the descending aorta, where the atheroprotective effects of PECAM-1 also required its expression on bone marrow–derived cells.
Conclusion—We conclude that PECAM-1 influences initiation and progression of atherosclerosis both positively and negatively, and that it does so in a site-specific manner. (Arterioscler Thromb Vasc Biol. 2008;28:1996-2002
Probing Gauge String Formation in a Superconducting Phase Transition
Superconductors are the only experimentally accessible systems with
spontaneously broken gauge symmetries which support topologically nontrivial
defects, namely string defects. We propose two experiments whose aim is the
observation of the dense network of these strings thought to arise, via the
Kibble mechanism, in the course of a spontaneous symmetry breaking phase
transition. We suggest ways to estimate the order of magnitude of the density
of flux tubes produced in the phase transition. This may provide an
experimental check for the theories of the production of topological defects in
a spontaneously broken gauge theory, such as those employed in the context of
the early Universe.Comment: 16 pages (Latex), 4 figures included, change in title, some minor
changes, published versio
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A new model of meteoric calcium in the mesosphere and lower thermosphere
Meteoric ablation produces layers of metal atoms in the mesosphere and lower thermosphere (MLT). It has been known for more than 30 years that the Ca atom layer is depleted by over 2 orders of magnitude compared with Na, despite these elements having nearly the same elemental abundance in chondritic meteorites. In contrast, the Ca+ ion abundance is depleted by less than a factor of 10. To explain these observations, a large database of neutral and ion–molecule reaction kinetics of Ca species, measured over the past decade, was incorporated into the Whole Atmosphere Community Climate Model (WACCM). A new meteoric input function for Ca and Na, derived using a chemical ablation model that has been tested experimentally with a Meteoric Ablation Simulator, shows that Ca ablates almost 1 order of magnitude less efficiently than Na. WACCM-Ca simulates the seasonal Ca layer satisfactorily when compared with lidar observations, but tends to overestimate Ca+ measurements made by rocket mass spectrometry and lidar. A key finding is that CaOH and CaCO3 are very stable reservoir species because they are involved in essentially closed reaction cycles with O2 and O. This has been demonstrated experimentally for CaOH, and in this study for CaCO3 using electronic structure and statistical rate theory. Most of the neutral Ca is therefore locked in these reservoirs, enabling rapid loss through polymerization into meteoric smoke particles, and this explains the extreme depletion of Ca
Pro-oxidant effect of α-tocopherol in patients with Type 2 Diabetes after an oral glucose tolerance test – a randomised controlled trial
BACKGROUND: As a part of a larger study investigating the effects of α-tocopherol on gene expression in type 2 diabetics we observed a pro-oxidant effect of α-tocopherol which we believe may be useful in interpreting outcomes of large intervention trials of α-tocopherol. METHODS: 19 type 2 diabetes subjects were randomised into two groups taking either 1200 IU/day of α-tocopherol or a matched placebo for 4 weeks. On day 0 and 29 of this study oxidative DNA damage was assessed in mononuclear cells from fasted blood samples and following a 2 h glucose tolerance test (GTT). RESULTS: On day 0 there was no significant difference in oxidative DNA damage between the two groups or following a GTT. On day 29 there was no significant difference in oxidative DNA damage in fasted blood samples, however following a GTT there was a significant increase in oxidative DNA damage in the α-tocopherol treatment group. CONCLUSION: High dose supplementation with α-tocopherol primes mononuclear cells from patients with type 2 diabetes for a potentially damaging response to acute hyperglycaemia
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