1,212 research outputs found

    Modified capsulorhexis for fluid-filled mature cataracts

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    Background: The aim of this study was to develop a modified capsulorhexis technique featuring a new maneuver for the removal of subcortical fluid in fluid-filled mature cataracts to avoid high intralenticular pressure. Methods: This prospective interventional study included 33 eyes with mature cataracts and evidence of subcapsular fluid spaces by slit lamp examination.  For each patient, 20% mannitol was administered intravenously according to the bodyweight 1 h preoperatively. Under peribulbar anesthesia, a 2.2-mm main incision was made, and the anterior chamber was filled with a dispersive ophthalmic viscosurgical device. Using a bent-tip cystotome, a 2-mm curved incision was made in the center of the anterior capsule, which released subcortical fluid and was drained through compression of the posterior lip of the main incision using a spatula. Then, fine gentle milking in all quadrants around the puncture on the anterior lens capsule from the periphery toward the site of puncture using the blunt-edged spatula further assists drainage of subcortical fluid and breaks fine septa inside the lens to remove fluid from intralenticular fluid pocket collections. Results: The study included 15 (45.5%) men and 18 (54.5%) women with a mean ± standard deviation (SD) of age of 63.2 ± 5.33 and 64.4 ± 6.21 years, respectively. The modified capsulorhexis technique was performed for 33 intumescent cataracts. Capsulorhexis was completed in all cases; capsulorhexis was easy in 31 (94%) eyes and difficult in 2 (6%) eyes. In the two difficult cases, radial extension occurred in one eye, and it was retrieved using the Little technique; the other case with radial tear was completed successfully using a retinal micro scissor from the other edge of the capsulorhexis until reaching an oval, continuous capsulorhexis. Conclusions: This modified capsulorhexis technique with compression on the posterior lip of the main incision and capsule milking allowed for a safe, continuous curvilinear capsulorhexis. Further comparative studies are necessary to confirm our preliminary results

    Number of vortices generated in a rotating Bose-Einstein condensates in two-dimensional optical lattice

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    In the present paper we calculate the number of vortices generated in a rotating Bose-Einstein condensate in two-dimensional optical lattice. Our approach enabled us to parametrize the vortices number in terms of the thermodynamic potential q(T)q(T) for the system under consideration. The thermodynamic potential is calculated using the semiclassical approximation approach. The finite size and the interatomic interaction effects are investigated. The calculated results show that the vortices number as a function of the angular velocity of rotation rate depends on the normalized temperature, number of particles, interatomic interaction, and optical potential

    Acceleration and Particle Field Interactions of Cosmic Rays I: Formalism

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    The acceleration of ultra high energy cosmic rays is conjectured to occur through various interactions with the electromagnetic fields in different astrophysical objects, like magnetic matter clumps, besides the well-known shock and stochastic Fermi mechanisms. It is apparent that the latter are not depending on the particle's charge, quantitatively. Based on this model, a considerable portion of the dynamics, that derives a charged particle parallel to a magnetic field B\mathbf{B} and under the influence of a force F\mathbf{F}, is assumed to be composed of an acceleration by a non-magnetic force F\mathbf{F}_{\parallel} and a gyromotion along B\mathbf{B} direction, plus drifts in the direction of F\mathbf{F}_{\perp}. The model and its formalism are introduced. Various examples for drift motions and accelerating forces are suggested. The formalism is given in a non-relativistic version. Obviously, the translation into the relativistic version is standard. In a forthcoming work, a quantitative estimation of the energy gained by charged cosmic rays in various astrophysical objects will be evaluated.Comment: 9 pages, 2 EPS figure

    Underdetermined blind source separation based on Fuzzy C-Means and Semi-Nonnegative Matrix Factorization

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    Conventional blind source separation is based on over-determined with more sensors than sources but the underdetermined is a challenging case and more convenient to actual situation. Non-negative Matrix Factorization (NMF) has been widely applied to Blind Source Separation (BSS) problems. However, the separation results are sensitive to the initialization of parameters of NMF. Avoiding the subjectivity of choosing parameters, we used the Fuzzy C-Means (FCM) clustering technique to estimate the mixing matrix and to reduce the requirement for sparsity. Also, decreasing the constraints is regarded in this paper by using Semi-NMF. In this paper we propose a new two-step algorithm in order to solve the underdetermined blind source separation. We show how to combine the FCM clustering technique with the gradient-based NMF with the multi-layer technique. The simulation results show that our proposed algorithm can separate the source signals with high signal-to-noise ratio and quite low cost time compared with some algorithms

    The dilemma of internal audit function adaptation: The impact of ERP and corporate governance pressures

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    © Emerald Group Publishing Limited. Purpose: The purpose of this paper is to provide a conceptual framework that helps to investigate how the internal audit function (IAF) responds to both the introduction of the control logic of Enterprise Resource Planning (ERP) systems, and corporate governance’s (CG) institutional pressures. Furthermore, the paper aims to articulate the concurrence between the external pressures of CG and internal control logic of ERP systems. Design/methodology/approach: The paper presents a review of the normative literature pertaining to the increase in significance of CG in the light of the worldwide economic crisis. The paper highlights a literature gap related to the lack of studies focusing on the impact of ERP systems implementation on the IAF practices. Findings: The authors articulate institutional theory to formulate a conceptual framework that explains the reciprocal interplay between the macro external governance pressures, micro internal institutional logics inscribed in the ERP systems and their effect on IAF practices and structure within organisations. Research limitations/implications: The paper is conceptual in nature and therefore the proposed framework will be subsequently validated using a qualitative research approach in future research. Practical implications: The conceptual framework would offer the internal auditors some strategies for enabling adaptation to the different internal and external pressures. Also the paper provides a platform for research community to investigate the influence of CG and ERP systems implementation on IAF adaptation. Originality/value: The paper provides a clearer articulation of the various constructs that affect the IAF, which has gained great attention for assuring good CG

    (R1989) Mixed Convection Slippery Cross Fluid Flow due to a Stratified Sheet under the Effect of Radiation Phenomenon

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    In view of the meaning of a two dimensional laminar Cross liquid in depicting an exhaustive assortment of experimental information, an assessment is done for a numerical and mathematical arrangement over a stratified extensible sheet. The non-dimensionality technique is brought into the controlling equations within the sight of the slip phenomenon and to make the solution more thorough. The data have been taken at a steady, viscous and laminar ow. Heat transfer across fluid is employed as a non-Newtonian fluid, where the fluid has a affected by radiation. Additionally, thermal radiation and heat generation are considered with the basic influence on the temperature field. The work has been performed to yield a completely new concept of the presence relationship between the governing parameters and the rate of heat transfer. Numerical analysis with the aid of the shooting method of the governing equations of motion is given over a wide range of controlling parameters. A bunch of graph plots both velocity and temperature fields at various upsides of physical parameters. Furthermore, a tabular form of the same parameters exists for the local shear stress and the rate of heat transfer along the sheet
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