20,081 research outputs found
Central Limit Theorems for Supercritical Superprocesses
In this paper, we establish a central limit theorem for a large class of
general supercritical superprocesses with spatially dependent branching
mechanisms satisfying a second moment condition. This central limit theorem
generalizes and unifies all the central limit theorems obtained recently in
Mi{\l}o\'{s} (2012, arXiv:1203:6661) and Ren, Song and Zhang (2013, to appear
in Acta Appl. Math., DOI 10.1007/s10440-013-9837-0) for supercritical super
Ornstein-Uhlenbeck processes. The advantage of this central limit theorem is
that it allows us to characterize the limit Gaussian field. In the case of
supercritical super Ornstein-Uhlenbeck processes with non-spatially dependent
branching mechanisms, our central limit theorem reveals more independent
structures of the limit Gaussian field
Central Limit Theorems for Super-OU Processes
In this paper we study supercritical super-OU processes with general
branching mechanisms satisfying a second moment condition. We establish central
limit theorems for the super-OU processes. In the small and crtical branching
rate cases, our central limit theorems sharpen the corresponding results in the
recent preprint of Milos in that the limit normal random variables in our
central limit theorems are non-degenerate. Our central limit theorems in the
large branching rate case are completely new. The main tool of the paper is the
so called "backbone decomposition" of superprocesses
Spin-Cherenkov effect in a magnetic nanostrip with interfacial Dzyaloshinskii-Moriya interaction
Spin-Cherenkov effect enables strong excitations of spin waves (SWs) with
nonlinear wave dispersions. The Dzyaloshinskii-Moriya interaction (DMI) results
in anisotropy and nonreciprocity of SWs propagation. In this work, we study the
effect of the interfacial DMI on SW Cherenkov excitations in permalloy
thin-film strips within the framework of micromagnetism. By performing
micromagnetic simulations, it is shown that coherent SWs are excited when the
velocity of a moving magnetic source exceeds the propagation velocity of the
SWs. Moreover, the threshold velocity of the moving magnetic source with finite
DMI can be reduced compared to the case of zero DMI. It thereby provides a
promising route towards efficient SW generation and propagation, with potential
applications in spintronic and magnonic devices.Comment: 6 pages, 5 figures. To be published in Scientific Report
Acetaldehyde Induces Cytotoxicity of SH-SY5Y Cells via Inhibition of Akt Activation and Induction of Oxidative Stress
Excessive alcohol consumption can lead to brain tissue damage and cognitive dysfunction. It has been shown that heavy drinking is associated with an earlier onset of neurodegenerative diseases such as Alzheimer’s disease. Acetaldehyde, the most toxic metabolite of ethanol, is speculated to mediate the brain tissue damage and cognitive dysfunction induced by the chronic excessive consumption of alcohol. However, the exact mechanisms by which acetaldehyde induces neurotoxicity are not totally understood. In this study, we investigated the cytotoxic effects of acetaldehyde in SH-SY5Y cells and found that acetaldehyde induced apoptosis of SH-SY5Y cells by downregulating the expression of antiapoptotic Bcl-2 and Bcl-xL and upregulating the expression of proapoptotic Bax. Acetaldehyde treatment led to a significant decrease in the levels of activated Akt and cyclic AMP-responsive element binding protein (CREB). In addition, acetaldehyde induced the activation of p38 mitogen-activated protein kinase (MAPK) while inhibiting the activation of extracellular signal-regulated kinases (ERKs, p44/p42MAPK). Meanwhile, acetaldehyde treatment caused an increase in the production of reactive oxygen species and elevated the oxidative stress in SH-SY5Y cells. Therefore, acetaldehyde induces cytotoxicity of SH-SY5Y cells via promotion of apoptotic signaling, inhibition of cell survival pathway, and induction of oxidative stress
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