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We study the diffusion of a particle with a time-dependent diffusion coefficient D(t) that switches between random values drawn from a distribution W(D) at a fixed rate r. Using a renewal approach, we compute exactly the moments of the position of the particle ⟨x^{2n}(t)⟩ at any finite time t, and for any W(D) with finite moments ⟨D^{n}⟩. For t≫1, we demonstrate that the cumulants ⟨x^{2n}(t)⟩_{c} grow linearly with t and are proportional to the free cumulants of a random variable distributed according to W(D). For specific forms of W(D), we compute the large deviations of the position of the particle, uncovering rich behaviors and dynamical transitions of the rate function I(y=x/t). Our analytical predictions are validated numerically with high precision, achieving accuracy up to 10^{-2000}.
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http://dx.doi.org/10.1103/rqsn-bzr6 | DOI Listing |
BMC Emerg Med
September 2025
Department of Neurology and Clinical Neuroscience, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany.
Background: Identifying suspected anterior circulation large-vessel occlusion (aLVO) strokes during emergency calls could enhance dispatch efficiency, particularly in rural areas. However, data on emergency medical dispatchers' (EMDs) ability to recognize aLVO symptoms remain limited. This simulation study aimed to evaluate the feasibility of identifying side-specific arm paresis, side-specific conjugate eye deviation (CED), and aphasia during emergency calls by instructing layperson callers to perform brief, standardized examination steps.
View Article and Find Full Text PDFFood Chem
September 2025
School of Pharmacy, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Yantai University, Yantai 264005, China. Electronic address: zh
In this study, a novel carbon dots-based system was developed for the sequential quantification of Au and L-cysteine (L-Cys). The system comprises N,F-doped carbon dots (N,F-CDs), a custom-designed miniaturized fluorimeter, and test strips. The N,F-CDs exhibit outstanding optical properties, including a large Stokes shift (127 nm) and high fluorescence intensity.
View Article and Find Full Text PDFAnal Chem
September 2025
Department of Chemistry, Wuhan University, Wuhan 430072, China.
Three-dimensional printing (3DP) technology enables the flexible fabrication of integrated monolithic microextraction chips for high-throughput sample pretreatment. Meanwhile, the extraction performance of 3DP-based channels is largely limited by printer resolution and the commercially available printing materials. In this work, a 3DP array monolithic microextraction chip (AMC) was fabricated by integrating 26-array helical monolithic microextraction channels for sample pretreatment and 52-array gas valves for fluid control.
View Article and Find Full Text PDFMol Biol Evol
September 2025
Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, College of Life Sciences, Beijing Normal University, Beijing 100875, China.
Recent theoretical and algorithmic advances in introgression detection, coupled with the growing availability of genome-scale data, have highlighted the widespread occurrence of interspecific gene flow across the tree of life. However, current methods largely depend on the molecular clock assumption-a questionable premise given empirical evidence of substitution rate variation across lineages. While such rate heterogeneity is known to compromise gene flow detection among divergent lineages, its impact on closely related taxa at shallow evolutionary timescales remains poorly understood, likely because these taxa are often assumed to adhere to a molecular clock.
View Article and Find Full Text PDFAm J Psychiatry
September 2025
Department of Psychiatry, School of Medicine, Yale University, New Haven.
This review examines ketamine's neurotoxic potential across preclinical and clinical studies. The authors synthesized data from preclinical models, then integrated findings from human clinical trials of esketamine and observational studies in recreational users. Animal studies have found that repeated or high-dose subanesthetic ketamine administration results in consistent excitotoxic neuronal damage and lasting cognitive deficits, especially in perinatal animals.
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