Results 61 to 70 of about 550,309 (325)

Covariate assisted screening and estimation

, 2014
Consider a linear model $Y=X\beta+z$, where $X=X_{n,p}$ and $z\sim N(0,I_n)$. The vector $\beta$ is unknown but is sparse in the sense that most of its coordinates are $0$. The main interest is to separate its nonzero coordinates from the zero ones (i.e.,
Fan, Jianqing, Jin, Jiashun, Ke, Zheng Tracy   +2 more
core   +1 more source

Pulse Pressure, White Matter Hyperintensities, and Cognition: Mediating Effects Across the Adult Lifespan

Annals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Objectives To investigate whether pulse pressure or mean arterial pressure mediates the relationship between age and white matter hyperintensity load and to examine the mediating effect of white matter hyperintensities on cognition. Methods Demographic information, blood pressure, current medication lists, and Montreal Cognitive Assessment ...
Jade Hannan, Sarah Newman‐Norlund, Natalie Busby, Sarah C. Wilson, Roger Newman‐Norlund, Chris Rorden, Julius Fridriksson, Leonardo Bonilha, Nicholas Riccardi   +8 more
wiley   +1 more source

Covariant Lyapunov vectors [PDF]

Journal of Physics A: Mathematical and Theoretical, 2013
The recent years have witnessed a growing interest for covariant Lyapunov vectors (CLVs) which span local intrinsic directions in the phase space of chaotic systems. Here we review the basic results of ergodic theory, with a specific reference to the implications of Oseledets' theorem for the properties of the CLVs.
Ginelli, Francesco, Chaté, Hugues, Livi, Roberto, Politi, Antonio   +3 more
openaire   +8 more sources

3D MRI Tract‐Specific Spinal Cord Lesion Pattern Improves Prediction of Distinct Neurological Recovery

Annals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Objective To distinguish lateralized motor‐ and sensory‐tract damage after acute spinal cord injury (SCI) and explore its predictive power for motor and sensory recovery. Methods Thirty‐five SCI patients (two female) from a multi‐center data set (placebo‐arm of the Nogo‐A‐Inhibition in SCI trial) underwent routine T2‐weighted sagittal MRI ...
Lynn Farner, Tim M. Emmenegger, Simon Schading‐Sassenhausen, Julia Berroth, Maryam Seif, Armin Curt, Patrick Freund, The Nogo Inhibition in Spinal Cord Injury Study Group   +7 more
wiley   +1 more source

Randomization Tests that Condition on Non-Categorical Covariate Balance

Journal of Causal Inference, 2019
A benefit of randomized experiments is that covariate distributions of treatment and control groups are balanced on average, resulting in simple unbiased estimators for treatment effects.
Branson Zach, Miratrix Luke W.
doaj   +1 more source

Covariance in plasticity [PDF]

Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2013
Covariance is imposed to the second law of thermodynamics and consequences are shown for elastic-perfectly plastic bodies. In this setting, pointwise balances of standard and configurational actions, constitutive restrictions on the first Piola–Kirchhoff stress and the Eshelby one, and the structure of the dissipation are all derived from a unique ...
openaire   +4 more sources

VISUALIZATION OF COVARIANCE AND CROSS-COVARIANCE FIELDS [PDF]

International Journal for Uncertainty Quantification, 2013
We present a numerical technique to visualize covariance and cross-covariance fields of a stochastic simulation. The method is local in the sense that it demonstrates the covariance structure of the solution at a point with its neighboring locations. When coupled with an efficient stochastic simulation solver, our framework allows one to effectively ...
Dongbin Xiu, Mike Kirby, Chao Yang
openaire   +2 more sources

Relevance of Kappa and Lambda Free Light Chains in Autoimmune Astrocytopathy Associated With Anti‐GFAP Antibodies

Annals of Clinical and Translational Neurology, EarlyView.
ABSTRACT Introduction The kappa‐free light chain (κ‐FLC) index is known to be highly sensitive and specific for diagnosing multiple sclerosis (MS), while little is understood about lambda (λ)‐FLC. This study assessed the κ‐FLC and λ‐FLC indices in autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy.
Michael Levraut, Romain Marignier, Mikael Cohen, Jeanne Benoit, Cassandre Landes‐Chateau, Elisabeth Maillart, Marion Cremoni, Barbara Seitz‐Polski, Anne‐Laurie Pinto, Pauline Dumez, Jérôme Honnorat, Christine Lebrun‐Frenay   +11 more
wiley   +1 more source

Data-driven Algorithms for Dimension Reduction in Causal Inference

, 2016
In observational studies, the causal effect of a treatment may be confounded with variables that are related to both the treatment and the outcome of interest.
de Luna, Xavier, Häggström, Jenny, Persson, Emma, Waernbaum, Ingeborg   +3 more
core   +1 more source

Covariance Hypotheses Which are Linear in Both the Covariance and the Inverse Covariance

The Annals of Statistics, 1988
The author has studied the structure of statistical hypotheses for the family of normal distributions, which are linear in both the covariance and the inverse covariance. It is shown that such hypotheses are products of models each of which consist of either i.i.d. random vectors which have a covariance with a real, complex or quaternion structure or i.
openaire   +4 more sources