Stochastic Kinetics of Intracellular Calcium Oscillations

A stochastic model of intracellular calcium oscillations is put forward by taking into account the random opening closing of Ca 2+ channels in endoplasmic reticulum (ER) membrane. The numerical results of the stochastic model show simple and complex calcium oscillations, which accord with the experiment results.

Impacts of Randomly Distributed Small-Scale Vortices on Typhoon Tracks

Impacts of small-scale vortices on typhoon or tropical cyclone（TC） tracks in a system of three components （an idealized subtropical high ridge,a TC,and small-scale vortices） were examined numerically using a barotropic primitive equation model and idealized initial fields.Two small-scale vorticity fields were generated stochastically,where the number of initial small-scale vortices is 100.In the two fields,the number, size,structure as well as the total kinetic energy of the small-scale vortices were all the same,but their center coordinates were randomly distributed.Two experiments,named EXA and EXB,with the integration time of 56 h,were performed. Comparison of the integration outputs from the two experiments indicates that various small-scale vorticity fields involved could produce both various horizontal winds in the TC outer area and various intensities of the environmental steering for TC.The values of the environmental flow speed along the east-west direction are 7.8,8.2,and 8.7 m s^（-1） in EXA and 8.3,9.5,and 9.7 m s^（-1） in EXB at t = 24,36,and 48 h,respectively. The values along the south-north direction are 0.9,1.8,and 2.5 m s^（-1） in EXA and 2.3,2.3,and 5.9 m s^（-1） in EXB,respectively.The various intensities of the environmental steering could lead to various TC center positions.For example,the difference between the coordinates of TC centers in EXA and EXB reaches 120 km at t = 48 h,which is about 56%of the prediction error of TC tracks in the northwestern Pacific region derived from eight operational models. Dynamics of the interplays between a subtropical high ridge and a TC in previous works has shown that when the TC was located equatorwards of the subtropical ridge,the relationship between the propagation of TC and the local absolute vorticity gradient was characterized by points scattered around their mean values.After introducing the stochastic vorticity field into the model,the interplays among the subtropical high ridge,the TC,and small-scale vortices might make this relationship more complex,that is,besides the scattered points,there also exists a high correlation between the propagation of TC and the local absolute vorticity gradient.

Abnormal Effective Connectivity in the Brain is Involved in Auditory Verbal Hallucinations in Schizophrenia

Information flow among auditory and language processing-related regions implicated in the pathophysiology of auditory verbal hallucinations（AVHs） in schizophrenia（SZ） remains unclear. In this study, we used stochastic dynamic causal modeling（s DCM） to quantify connections among the left dorsolateral prefrontal cortex（inner speech monitoring）, auditory cortex（auditory processing）, hippocampus（memory retrieval）, thalamus（information filtering）, and Broca＇s area（language production） in 17 first-episode drug-na？¨ve SZ patients with AVHs, 15 without AVHs, and 19 healthy controls using resting-state functional magnetic resonance imaging.Finally, we performed receiver operating characteristic（ROC） analysis and correlation analysis between image measures and symptoms. s DCM revealed an increasedsensitivity of auditory cortex to its thalamic afferents and a decrease in hippocampal sensitivity to auditory inputs in SZ patients with AVHs. The area under the ROC curve showed the diagnostic value of these two connections to distinguish SZ patients with AVHs from those without AVHs. Furthermore, we found a positive correlation between the strength of the connectivity from Broca＇s area to the auditory cortex and the severity of AVHs. These findings demonstrate, for the first time, augmented AVHspecific excitatory afferents from the thalamus to the auditory cortex in SZ patients, resulting in auditory perception without external auditory stimuli. Our results provide insights into the neural mechanisms underlying AVHs in SZ. This thalamic-auditory cortical-hippocampal dysconnectivity may also serve as a diagnostic biomarker of AVHs in SZ and a therapeutic target based on direct in vivo evidence.