We establish global rates of convergence for the Maximum Likelihood Estimators (MLEs) of log-concave and -concave densities on ℝ. The main finding is that the rate of convergence of the MLE in the Hellinger metric is no worse than when -1 < < ∞ where = 0 corresponds to the log-concave case. We also show that the MLE does not exist for the classes of -concave densities with < -1.
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http://dx.doi.org/10.1214/15-AOS1394 | DOI Listing |
Biophys J
January 2025
Department of Pharmacology, School of Medicine, University of California San Diego, CA 92093, USA; Department of Mechanical and Aerospace Engineering, University of California San Diego, CA 92093, USA. Electronic address:
Synaptic morphology plays a critical role in modulating the dynamics of neurotransmitter diffusion and receptor activation in interneuron communication. Central physical aspects of synaptic geometry, such as the curvature of the synaptic cleft, the distance between the presynaptic and postsynaptic membranes, and the surface area-to-volume ratio of the cleft, crucially influence glutamate diffusion and N-Methyl-D-Aspartate receptor (NMDAR) opening probabilities. In this study, we developed a stochastic model for receptor activation using realistic synaptic geometries.
View Article and Find Full Text PDFBayesian Anal
June 2024
Department of Statistics, Purdue University, West Lafayette, IN 47907, USA.
The exponential random graph model (ERGM) is a popular model for social networks, which is known to have an intractable likelihood function. Sampling from the posterior for such a model is a long-standing problem in statistical research. We analyze the performance of the stochastic gradient Langevin dynamics (SGLD) algorithm (also known as noisy Longevin Monte Carlo) in tackling this problem, where the stochastic gradient is calculated via running a short Markov chain (the so-called inner Markov chain in this paper) at each iteration.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Departament de Ciència de Materials i Química Física & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, c/Martí i Franquès 1-11, Barcelona 08028, Spain.
The interaction between molybdenum carbide (MoC) nanoparticles and both flat and curved graphene surfaces, serving as models for carbon nanotubes, was investigated by means of density functional theory. A variety of MoC nanoparticles with different sizes and stoichiometries have been used to explore different adsorption sites and modes across models with different curvature degrees. On flat graphene, off-stoichiometric MoC featuring more low-coordinated Mo atoms exhibits stronger interaction and increased electron transfers from the carbide to the carbon substrate.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Henan Key Laboratory of Crystalline Molecular Functional Materials, College of Chemistry and Pingyuan Laboratory, Zhengzhou University, Zhengzhou, 450001, China.
Curvature-induced interfacial electric field effects and local strain engineering offer a powerful approach for optimizing the intrinsic catalytic activity of single-atom catalysts (SACs). Investigations into the surface curvature on SACs are still ongoing, and the impact of the concave surface is often overlooked. In this work, theoretical calculations indicate that curved surfaces, particularly those with concavity, can optimize the electronic structures of single Fe sites and facilitate the reductive release of *OH.
View Article and Find Full Text PDFBrain Struct Funct
December 2024
Center for Advanced Imaging Innovation and Research (CAI2R), Department of Radiology, New York University Grossman School of Medicine, New York, United States.
The corpus callosum (CC) is the most important interhemispheric white matter (WM) structure composed of several anatomically and functionally distinct WM tracts. Resolving these tracts is a challenge since the callosum appears relatively homogenous in conventional structural imaging. Commonly used callosal parcellation methods such as Hofer and Frahm scheme rely on rigid geometric guidelines to separate the substructures that are limited to consider individual variation.
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