Search results for "Computation"

Approximation of Baskakov type Pólya–Durrmeyer operators

2017

In the present paper we propose the Durrmeyer type modification of Baskakov operators based on inverse Polya-Eggenberger distribution. First we estimate a recurrence relation by using hypergeometric series. We give a global approximation theorem in terms of second order modulus of continuity, a direct approximation theorem by means of the Ditzian-Totik modulus of smoothness and a Voronovskaja type theorem. Some approximation results in weighted space are obtained. Also, we show the rate of convergence of these operators to certain functions by illustrative graphics using the Maple algorithms.

G.O.2 Proteomic identification of the LIM domain protein FHL1 as the gene-product mutated in reducing body myopathy

2008

Cover Feature: Synthesis of Polycyclic Indolines by Utilizing a Reduction/Cyclization Cascade Reaction (Eur. J. Org. Chem. 45/2021)

2021

Reducing CAS-SDCI space. Using selected spaces in configuration interaction calculations in an efficient way

2002

A new method is presented, which allows an important reduction of the size of some Configuration Interaction (CI) matrices. Starting from a Complete Active Space (CAS), the numerous configurations that have a small weight in the CAS wave function are eliminated. When excited configurations (e.g., singly and doubly excited) are added to the reference space, the resulting MR-SDCI space is reduced in the same proportion as compared with the full CAS–SDCI. A set of active orbitals is chosen, but some selection of the most relevant excitations is performed because not all the possible excitations act as SDCI generators. Thanks to a new addressing technique, the computational time is drastically …

Optimizing H.264/AVC interprediction on a GPU-based framework

2011

H.264/MPEG-4 part 10 is the latest standard for video compression and promises a significant advance in terms of quality and distortion compared with the commercial standards currently most in use such as MPEG-2 or MPEG-4. To achieve this better performance, H.264 adopts a large number of new/improved compression techniques compared with previous standards, albeit at the expense of higher computational complexity. In addition, in recent years new hardware accelerators have emerged, such as graphics processing units (GPUs), which provide a new opportunity to reduce complexity for a large variety of algorithms. However, current GPUs suffer from higher power consumption requirements because of…

Calculation of excitation energies from the CC2 linear response theory using Cholesky decomposition

2014

A new implementation of the approximate coupled cluster singles and doubles CC2 linear response model is reported. It employs a Cholesky decomposition of the two-electron integrals that significantly reduces the computational cost and the storage requirements of the method compared to standard implementations. Our algorithm also exploits a partitioning form of the CC2 equations which reduces the dimension of the problem and avoids the storage of doubles amplitudes. We present calculation of excitation energies of benzene using a hierarchy of basis sets and compare the results with conventional CC2 calculations. The reduction of the scaling is evaluated as well as the effect of the Cholesky …

Cost-effective Multiresolution schemes for Shock Computations

2009

Harten's Multiresolution framework has provided a fruitful environment for the development of adaptive codes for hyperbolic PDEs. The so-called cost-effective alternative [4,8,21] seeks to achieve savings in the computational cost of the underlying numerical technique, but not in the overall memory requirements of the code. Since the data structure of the basic algorithm does not need to be modified, it provides a set of tools that can be easily implemented into existing codes and that can be very useful in order to speed up the numerical simulations involved in the testing process that is associated to the development of new numerical schemes.
In this paper we present two different applica…

Goethe's dream

2009

The German philosopher Immanuel Kant (1724–1804) defined living organisms as objects with an intrinsic purpose, which are self‐organized in such a way that every part is a function of the whole and the whole is a function of every part, and in which “nothing is for nothing”. Kant already anticipated the tension between agency and structure, and between forward and backward causation. He also perceived living beings as entities that, being extremely complex, are not amenable to descriptions based on laws that are similar to the fundamental laws of physics: “There will never be a Newton of a grass blade,” he wrote. Less metaphorically, Kant believed that science would not be able to understan…

Genetic variants linked to myopic macular degeneration in persons with high myopia: CREAM Consortium.

2019

Purpose: To evaluate the roles of known myopia-associated genetic variants for development of myopic macular degeneration (MMD) in individuals with high myopia (HM), using case-control studies from the Consortium of Refractive Error and Myopia (CREAM). Methods: A candidate gene approach tested 50 myopia-associated loci for association with HM and MMD, using meta-analyses of case-control studies comprising subjects of European and Asian ancestry aged 30 to 80 years from 10 studies. Fifty loci with the strongest associations with myopia were chosen from a previous published GWAS study. Highly myopic (spherical equivalent [SE] ≤ -5.0 diopters [D]) cases with MMD (N = 348), and two sets of cont…

Understanding the influence of lewis acids in the regioselectivity of the diels-alder reactions of 2-methoxy-5-methyl-1,4-benzoquinone: a dft study

2009

The mechanisms of the Diels–Alder (DA) reactions of 2-methoxy-5-methyl-1,4-benzoquinone 1 with 2-methyl-1,3-butadiene 2, in the absence and in the presence of LA catalysts, have been studied using the DFT method at the B3LYP/6-31G(d) level of theory. The uncatalyzed DA reactions between 1 and 2 take place via synchronous concerted TSs. The large activation barrier as well as the low stereo and regioselectivity associated with the uncatalyzed process are in clear agreement with the non-polar character of the cycloaddition. Coordination of the LA catalysts, BF3 or SnCl4, to the oxygen atoms of the benzoquinone 1 produces a large acceleration of the reaction, which can be associated with the l…