Results 31 to 40 of about 6,829 (292)

On Elastic Stability and Positive Definiteness for One-Dimensional Quasicrystals

open access: yesCrystals
In this work, a proper formulation of the elastic stability and positive definiteness of the elastic energy density of one-dimensional quasicrystals is provided. Based on an appropriate Voigt notation, the Sylvester criterion is applied and the necessary
Eleni Agiasofitou, Markus Lazar
doaj   +1 more source

Products of positive definite matrices. II [PDF]

open access: yesPacific Journal of Mathematics, 1967
I. The author gives, for every positive integer \(j\), necessary and sufficient conditions for a \(2\times 2\) real matrix (with positive determinant) to be a product of \(j\) positive definite real symmetric matrices (if \(j\ge 5\), every real matrix with positive determinant can be written as such a product).
openaire   +6 more sources

Insights Into the Antigenic Repertoire of Unclassified Synaptic Antibodies

open access: yesAnnals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Objective We sought to characterize the sixth most common finding in our neuroimmunological laboratory practice (tissue assay‐observed unclassified neural antibodies [UNAs]), combining protein microarray and phage immunoprecipitation sequencing (PhIP‐Seq). Methods Patient specimens (258; 133 serums; 125 CSF) meeting UNA criteria were profiled;
Michael Gilligan   +22 more
wiley   +1 more source

New iterative criteria for strong H $\mathcal{H}$ -tensors and an application

open access: yesJournal of Inequalities and Applications, 2017
Strong H $\mathcal{H}$ -tensors play an important role in identifying the positive definiteness of even-order real symmetric tensors. In this paper, some new iterative criteria for identifying strong H $\mathcal{H}$ -tensors are obtained.
Jingjing Cui   +3 more
doaj   +1 more source

M-Eigenvalues-Based Sufficient Conditions for the Positive Definiteness of Fourth-Order Partially Symmetric Tensors

open access: yesComplexity, 2020
M-eigenvalues of fourth-order partially symmetric tensors play important roles in the nonlinear elastic material analysis and the entanglement problem of quantum physics.
Gang Wang, Linxuan Sun, Lixia Liu
doaj   +1 more source

Sex Hormones Associate With Amyotrophic Lateral Sclerosis Risk and Survival

open access: yesAnnals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Amyotrophic lateral sclerosis (ALS) risk differs by sex and age, implicating sex hormones as potential modifiers. This study examined plasma levels of biologically active sex hormones and their association with ALS odds and survival in cases (females n = 131, males n = 189) and controls (females n = 138, males n = 150) from the University of ...
Stephen A. Goutman   +5 more
wiley   +1 more source

New criteria for H-tensors and an application

open access: yesOpen Mathematics, 2015
Some new criteria for identifying H-tensors are obtained. As an application, some sufficient conditions of the positive definiteness for an even-order real symmetric tensor are given. Advantages of results obtained are illustrated by numerical examples.
Wang Feng, Sun Deshu
doaj   +1 more source

New iterative codes for 𝓗-tensors and an application

open access: yesOpen Mathematics, 2016
New iterative codes for identifying 𝓗 -tensor are obtained. As an application, some sufficient conditions of the positive definiteness for an even-order real symmetric tensor, i.e., an even-degree homogeneous polynomial form are given.
Wang Feng, Sun Deshu
doaj   +1 more source

Transporting positive definiteness

open access: yesActa Scientiarum Mathematicarum, 2022
AbstractThis is a rough guide to the topic which might be worthy to develop further on. Expanding positive definiteness beyond its presupposed scope is intriguing due to a number of possible applications. The paper though looking at the first glance a little bit sketchy may provide a basis for further research.
openaire   +3 more sources

Hip morphology‐based osteoarthritis risk prediction models: development and external validation using individual participant data from the World COACH Consortium

open access: yesArthritis Care &Research, Accepted Article.
Objectives This study aims to develop hip morphology‐based radiographic hip osteoarthritis (RHOA) risk prediction models and investigates the added predictive value of hip morphology measurements and the generalizability to different populations. Methods We combined data from nine prospective cohort studies participating in the World COACH consortium ...
Myrthe A. van den Berg   +26 more
wiley   +1 more source

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