50 research outputs found
Hamiltonian formulation of systems with linear velocities within Riemann-Liouville fractional derivatives
The link between the treatments of constrained systems with fractional
derivatives by using both Hamiltonian and Lagrangian formulations is studied.
It is shown that both treatments for systems with linear velocities are
equivalent.Comment: 10 page
Hamilton-Jacobi quantization of singular Lagrangians with linear velocities
In this paper, constrained Hamiltonian systems with linear velocities are
investigated by using the Hamilton-Jacobi method. We shall consider the
integrablity conditions on the equations of motion and the action function as
well in order to obtain the path integral quantization of singular Lagrangians
with linear velocities.Comment: late
Three methods for correction of astigmatism during phacoemulsification
Purpose: To compare the safety and efficacy of three methods for correcting pre-existing astigmatism during phacoemulsification. Methods: This prospective, comparative, non-randomized study was conducted from March 2010 to January 2011, and included patients with keratometric astigmatism �1.25 D undergoing cataract surgery. Astigmatism was corrected using the following approaches: limbal relaxing incisions (LRI) on the steep meridian, extension and suturing of the phaco incision created at the steep meridian (extended-on-axis incision, EOAI), and toric intraocular lens (tIOL) implantation. Keratometric and refractive astigmatism were evaluated 1, 8, and 24 weeks postoperatively. Results: Eighty-three eyes of 72 patients (35 male and 37 female) with mean age of 62.4 ± 14.3 (range, 41-86) years were enrolled. The astigmatism was corrected by using the LRI, EOAI and tIOL implantation methods in 17, 33 and 33 eyes, respectively. Postoperative uncorrected distance visual acuity (UDVA) was significantly improved in all three groups. The difference in postoperative UDVA was not statistically significant among the study groups throughout follow-up except at week 24, when UCVA was significantly better in the tIOL group as compared to the EOAI group (P = 0.024). There is no statistically significant difference of correction index and index of success between three groups at week 24 (P = 0.085 and P = 0.085 respectively). Conclusion: There was no significant difference in astigmatism reduction among the three methods of astigmatism correction during phacoemulsification. Each of these methods can be used at the discretion of the surgeon. © 2016 Journal of Ophthalmic and Vision Research
Geometric phase for mixed states: a differential geometric approach
A new definition and interpretation of geometric phase for mixed state cyclic
unitary evolution in quantum mechanics are presented. The pure state case is
formulated in a framework involving three selected Principal Fibre Bundles, and
the well known Kostant-Kirillov-Souriau symplectic structure on (co) adjoint
orbits associated with Lie groups. It is shown that this framework generalises
in a natural and simple manner to the mixed state case. For simplicity, only
the case of rank two mixed state density matrices is considered in detail. The
extensions of the ideas of Null Phase Curves and Pancharatnam lifts from pure
to mixed states are also presented.Comment: 22 pages, revtex
Entropy as a function of Geometric Phase
We give a closed-form solution of von Neumann entropy as a function of
geometric phase modulated by visibility and average distinguishability in
Hilbert spaces of two and three dimensions. We show that the same type of
dependence also exists in higher dimensions. We also outline a method for
measuring both the entropy and the phase experimentally using a simple
Mach-Zehnder type interferometer which explains physically why the two concepts
are related.Comment: 19 pages, 7 figure
Analysis of correction methods for ships' measured speed during sea trials
For all new ships sea trials should be carried out as a part of the delivery from the yard to the ship owner. An important part of the delivery sea trial is to determine the speed capability of the ship in the contractual condition, which is traditionally deep, calm water and no wind, at some specified loading condition. However, it is seldom possible to perform this particular test under such conditions, and when the test is done in other conditions, the result is corrected back to the contractual condition. The correction can be of a significant magnitude. The correction procedure can be influenced by different parameters such as wind resistance, shallow water effect, sea currents and added resistance due to diffraction. There are different experimental methods for correction of measured speed. Since the latter parameter is the most important between others, in this article added resistance due to diffraction has been calculated for three ships using existing methods and comparisoned with the speed correction result of shipbuilder company (Hyundai Heavy Industries). The results show considerable deviation between HHI sea trial speed correction method and other methods. So HHI added resistance calculation method needs to be revised
AmnioQuick® Duo+ for diagnosis of premature fetal membranes rupture
Background: Failure to identify women with premature fetal membranes rupture associated with infectious morbidities. Evaluation of the accuracy of AmnioQuick® Duo+ in diagnosing premature fetal membranes rupture compared to conventional diagnostic tests was the aim of this study.Methods: 220 pregnant women ≥37 and <39 weeks` gestation studied and classified into two groups; study group (premature fetal membranes rupture) and control group (no premature fetal membranes rupture). Participants examined by trans-abdominal ultrasound (TAS) and vaginal speculum to visualize amnion leaking and for collection of samples for fern, nitrazine and AmnioQuick® Duo+ tests on admission. A final diagnosis whether the studied women had PROM or not at the initial presentation made after delivery.Results: Sensitivity and specificity of the AmnioQuick® Duo+ to diagnose PROM was 93.6% and 86.4%; respectively compared with 72.7% and 80.9%; respectively for fern test and 76.4% and 83.6%; respectively for nitrazine test. Positive predictive value, negative predictive value and accuracy of AmnioQuick® Duo+ to detect PROM were 87.3%, 93.1% and 90%; respectively compared with 79.2%, 74.8% and 76.8%; respectively for fern test and 82.4%, 77.97% and 80%; respectively for nitrazine test. AmnioQuick® Duo+ test had higher accuracy to detect premature fetal membranes rupture compared to conventional diagnostic tests.Conclusions: AmnioQuick® Duo+ is accurate bedside immunoassay test, better than the individual conventional diagnostic tests and can used as complementary test to improve the management of women with women premature fetal membranes rupture
Quantum Particle-Trajectories and Geometric Phase
"Particle"-trajectories are defined as integrable paths
in projective space.
Quantum states evolving on such trajectories, open or closed, do not
delocalise in projection, the phase associated with the trajectories
being related to the geometric (Berry) phase and the Classical Mechanics
action. High Energy Physics properties of states evolving on
"particle"-trajectories are discussed.Comment: 4 page