Results 111 to 120 of about 531,665 (271)
Bioenergy Cropping Reduces the Spatiotemporal Scaling of Soil Bacterial Biodiversity
Advanced Science, EarlyView.Consistent with patterns observed in plant and animal communities, soil bacterial communities exhibit significant species–time–area and phylogenetic–time–area relationships independent of nested structure. Bioenergy cropping significantly reduces the spatiotemporal scaling rates, particularly in sandy loam soils.
Zhencheng Ye +19 more
wiley +1 more source
Spectral guided sparse inverse covariance estimation of metabolic networks in Parkinson's disease. [PDF]
Neuroimage, 2021 Spetsieris PG, Eidelberg D.
europepmc +1 more source
Masked Toeplitz covariance estimation
, 2017 The problem of estimating the covariance matrix $ $ of a $p$-variate distribution based on its $n$ observations arises in many data analysis contexts. While for $n>p$, the classical sample covariance matrix $\hat _n$ is a good estimator for $ $, it fails in the high-dimensional setting when $n\ll p$.
Kabanava, Maryia, Rauhut, Holger
openaire +2 more sources
Advanced Science, EarlyView.This study combines full‐field tomography with diffraction mapping to quantify radial (ε002$\varepsilon _{002}$) and axial (ε100$\varepsilon _{100}$) lattice strain in wrinkled carbon‐fiber specimens for the first time. Radial microstrain gradients (−14.5 µεMPa$\varepsilon \mathrm{MPa}$−1) are found to signal damage‐prone zones ahead of failure, which ...
Hoang Minh Luong +7 more
wiley +1 more source
Estimating covariance matrices II
Journal of Multivariate Analysis, 1991 AbstractLet S1 and S2 be two independent p × p Wishart matrices with S1 ∼ Wp(Σ1, n1) and S2 ∼ Wp(Σ2, n2). We wish to estimate ζ = Σ2Σ1−1 under the loss function L1 = tr(ζ − ζ)′ Σ2−1(ζ − ζ) Σ1tr ζ. By extending the techniques of Berger, Haff, and Stein for the one sample problem, alternative estimators to the usual estimators for ζ are obtained. However,
openaire +1 more source
Advanced Science, EarlyView.Low‐frequency noise fingerprints in hafnia ferroelectrics provide a quantitative handle to resolve the long‐standing debate between polarization‐mediated and defect‐mediated switching. By tuning oxygen vacancy density via ALD O3 dose time and applying a physically constrained deconvolution, we extract bias‐resolved current fractions for both mechanisms
Ryun‐Han Koo +8 more
wiley +1 more source
IEEE Access, 2019 The covariance methods exert an effect on spatially colored (correlated) noise elimination during direction finding in multiple-input multiple-output (MIMO) radar.
Fangqing Wen, Zijing Zhang, Gong Zhang
doaj +1 more source
Inference about Clustering and Parametric Assumptions in Covariance Matrix Estimation [PDF]
Selecting an estimator for the variance covariance matrix is an important step in hypothesis testing. From less robust to more robust, the available choices include: Eicker/White heteroskedasticity-robust standard errors, Newey and West ...
Mikko Packalen, Tony Wirjanto
core
Advanced Science, EarlyView.This study firstly presents a comprehensive and high‐resolution pan‐3D genome resource in chicken. Our findings reveal the role of structural variations in 3D genome architectures, and how they influence the domestication process and production traits at the 3D genome level.
Zhen Zhou +19 more
wiley +1 more source
Sparse covariance estimation in heterogeneous samples
Electronic Journal of Statistics, 2011 Standard Gaussian graphical models (GGMs) implicitly assume that the conditional independence among variables is common to all observations in the sample. However, in practice, observations are usually collected form heterogeneous populations where such assumption is not satisfied, leading in turn to nonlinear relationships among variables.
Rodríguez, Abel +2 more
openaire +4 more sources