Search results for "ExAC"
showing 10 items of 1440 documents
Nonstationary distributions and relaxation times in a stochastic model of memristor
2020
We propose a stochastic model for a memristive system by generalizing known approaches and experimental results. We validate our theoretical model by experiments carried out on a memristive device based on multilayer structure. In the framework of the proposed model we obtain the exact analytic expressions for stationary and nonstationary solutions. We analyze the equilibrium and non-equilibrium steady-state distributions of the internal state variable of the memristive system and study the influence of fluctuations on the resistive switching, including the relaxation time to the steady-state. The relaxation time shows a nonmonotonic dependence, with a minimum, on the intensity of the fluct…
The problem of analytical calculation of barrier crossing characteristics for Levy flights
2008
By using the backward fractional Fokker-Planck equation we investigate the barrier crossing event in the presence of Levy noise. After shortly review recent results obtained with different approaches on the time characteristics of the barrier crossing, we derive a general differential equation useful to calculate the nonlinear relaxation time. We obtain analytically the nonlinear relaxation time for free Levy flights and a closed expression in quadrature of the same characteristics for cubic potential.
Nearly exact sample size calculation for powerful non-randomized tests for differences between binomial proportions
2015
In the case of two independent samples, it turns out that among the procedures taken in consideration, BOSCHLOO'S technique of raising the nominal level in the standard conditional test as far as admissible performs best in terms of power against almost all alternatives. The computational burden entailed in exact sample size calculation is comparatively modest for both the uniformly most powerful unbiased randomized and the conservative non-randomized version of the exact Fisher-type test. Computing these values yields a pair of bounds enclosing the exact sample size required for the Boschloo test, and it seems reasonable to replace the exact value with the middle of the corresponding inter…
Long read alignment based on maximal exact match seeds
2012
Abstract Motivation: The explosive growth of next-generation sequencing datasets poses a challenge to the mapping of reads to reference genomes in terms of alignment quality and execution speed. With the continuing progress of high-throughput sequencing technologies, read length is constantly increasing and many existing aligners are becoming inefficient as generated reads grow larger. Results: We present CUSHAW2, a parallelized, accurate, and memory-efficient long read aligner. Our aligner is based on the seed-and-extend approach and uses maximal exact matches as seeds to find gapped alignments. We have evaluated and compared CUSHAW2 to the three other long read aligners BWA-SW, Bowtie2 an…
Inhomogeneity and complexity measures for spatial patterns
2002
In this work, we examine two different measures for inhomogeneity and complexity that are derived from non-extensive considerations à la Tsallis. Their performance is then tested on theoretically generated patterns. All measures are found to exhibit a most sensitive behaviour for Sierpinski carpets. The procedures here introduced provide us with new, powerful Tsallis’ tools for analysing the inhomogeneity and complexity of spatial patterns.
Large-distance asymptotic behaviour of multi-point correlation functions in massless quantum models
2014
We provide a microscopic model setting that allows us to readily access to the large-distance asymptotic behaviour of multi-point correlation functions in massless, one-dimensional, quantum models. The method of analysis we propose is based on the form factor expansion of the correlation functions and does not build on any field theory reasonings. It constitutes an extension of the restricted sum techniques leading to the large-distance asymptotic behaviour of two-point correlation functions obtained previously.
On powerful exact nonrandomized tests for the Poisson two-sample setting.
2020
In the case of two independent samples from Poisson distributions, the natural target parameter for hypothesis testing is the ratio of the two population means. The conditional tests which have been derived for this class of problems already in the 1940s are well known to be optimal in terms of power only when randomized decisions between hypotheses are admitted at the boundary of the respective rejection regions. The major objective of this contribution is to show how the approach used by Boschloo in 1970 for constructing a powerful nonrandomized version of Fisher’s exact test for hypotheses about the odds ratio between two binomial parameters can successfully be adapted for the Poisson c…
Tucumanin, a β-hydroxy-γ-lactone bistetrahydrofuranic acetogenin from Annona cherimolia, is a potent inhibitor of mitochondrial complex I
2004
A new β-hydroxy-γ-methyl-γ-lactone bistetrahydrofuranic acetogenin, tucumanin, with the infrequent symmetrical threo/trans/threo/trans/ threo relative configuration at the tetrahydrofuran rings was isolated from Annona cherimolia (Annonaceae) seeds. The inhibitory potency on the mitochondrial complex I of acetogenins with this relative configuration (tucumanin and asimicin) was compared with that shown by the corresponding pairs with an asymmetrical threo/trans/threo/trans/erythro relative configuration (laherradurin/rolliniastatin-2, and itrabin/molvizarin). All these compounds act as selective inhibitors of mitochondrial complex 1 in the 0.18 - 1.55 nM range. Fil: Barrachina, Isabel. Univ…
DFT broken-symmetry exchange couplings calculation in a 1D chain of bridged iron basic carboxylates
2009
DFT broken-symmetry calculations at the B3LYP level were carried out to evaluate the exchange coupling constants defined by the Heisenberg-Dirac-van Vleck spin Hamiltonian (HDvV), Ĥ = -2JŜaŜb, in a 1D chain of iron basic carboxylate cores [Fe3O(Piv)6(H2O)] bridged by dicyanamide, and two related trinuclear Fe3O moieties. The chain complex was modeled as two Fe3O units that preserve all features of the repetitive unit in the infinite real system. All geometries were taken from the crystallographic data previously reported. The obtained calculated values for the J constants are in good agreement with experimental results. The weak anti-ferromagnetic inter-Fe3O core interaction along the chain…
Adducts of Tellurium Tetrachloride with Allyl Alcohol and Allyl Acetate: 1,2- vs 1,3-Addition and Structure and Dynamics of Te···O Interactions in D…
2002
The compounds Cl 3 Te[CH 2 CH(Cl)CH 2 O(H)...].Cl 2 Te[-CH 2 CH(Cl)CH 2 O-] (1) and Cl 3 Te-[CH 2 CH(CH 2 Cl)OC(CH 3 )=O...] (2) were prepared by the reaction of TeCl 4 with allyl alcohol and allyl acetate, respectively. Their molecular and crystal structures were investigated by single-crystal X-ray analysis, 1 H- 1 H-NOESY experiments, IR spectroscopy, and ab initio geometry optimization. 1 is a composite compound, whose subunits Cl 2 Te[-CH 2 CH(Cl)-CH 2 O-] (1A) and Cl 3 Te[CH 2 CH(Cl)CH 2 O(H))...] (1B) are linked in the solid state via Te...Cl-Te and O...H-O bridges. Both Te atoms are involved in similar five-membered rings, having a covalent Te-O bond in one case (1A) and a dative Te…