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1.
Guoliang Zhang & Tao Xiong 《Communications In Computational Physics》2022,32(1):126-155
We propose a high order finite difference linear scheme combined with a
high order bound preserving maximum-principle-preserving (MPP) flux limiter to
solve the incompressible flow system. For such problem with highly oscillatory structure but not strong shocks, our approach seems to be less dissipative and much less
costly than a WENO type scheme, and has high resolution due to a Hermite reconstruction. Spurious numerical oscillations can be controlled by the weak MPP flux
limiter. Numerical tests are performed for the Vlasov-Poisson system, the 2D guiding-center model and the incompressible Euler system. The comparison between the linear
and WENO type schemes, with and without the MPP flux limiter, will demonstrate the
good performance of our proposed approach. 相似文献
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目的:通过对同一患者双眼不同手术方式的自身对比,了解飞秒扫描后改SBK手术的疗效差异,为不同患者屈光手术方式的选择提供临床指导依据。方法回顾分析2例右眼行飞秒激光小切口透镜取出术( SMILE),左眼SMILE术中负压环脱失和激光扫描不良透镜分离困难而改行机械刀制瓣准分子激光手术( SBK)的患者,比较术后视力、等效球镜( SE)、对比敏感度( CSF)、波前像差( HAOS)以及泪膜破裂时间( BUT)、泪液分泌功能试验( Schimer I)和SPEED、OSDI干眼症状问卷调查分析差异。结果(1)术后个月,均能达到最佳矫正视力(BSCVA),等效球镜均在±0.75 D以内,双眼比较无显著性差异。(2)CSF的比较,左右眼无显著性差异,略低于正常水平。(3)术后3个月,BUT和Schimer检查中,双眼无显著性差异。(4)HAOS比较中,总像差RMS和高阶像差这两项, SMILE眼低于SBK眼;球差(S)的比较,SMILE眼高于SBK眼。(5)SPEED和OSDI问卷评分双眼无显著差异。结论 SMILE失败眼改SBK后视觉质量与SMILE眼无显著差异,其视觉质量、疗效不受影响。 相似文献
4.
摘 要 目的 了解脑卒中患者运动自我效能及生活质量水平并探讨两者的相关性。方法 采用一般资料调查表、运动自我效能量表(ESES)和脑卒中影响量表(SIS)对福州市2所三甲医院202例脑卒中患者进行问卷调查。结果 脑卒中患者运动自我效能总得分为(30.72±2.94)分,生活质量总得分为(67.14±4.54)分,均处于中等水平;患者运动自我效能总得分与生活质量总得分及力气、情绪、交流、日常生活活动能力、移动能力和手功能6个维度得分均呈正相关关系(P<0.01)。结论 脑卒中患者运动自我效能与生活质量密切相关,提示医护人员可以通过提高脑卒中患者运动自我效能来促进其生活质量的提升。 相似文献
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6.
Steve Majerus Anne-Lise Leclercq Aurélie Grossmann Monique Touzin Martine Poncelet 《Cortex; a journal devoted to the study of the nervous system and behavior》2009,45(6):708-720
This study re-explored the nature of verbal short-term memory (STM) deficits in children with specific language impairment (SLI), by distinguishing item and serial order STM processes. Recent studies have shown serial order STM capacity to be a critical determinant of language development, relative to item STM. In Experiment 1, 12 children with SLI, 12 age-matched children and 12 language-matched children were administered serial order recognition and reconstruction tasks. Experiment 2 assessed implicit serial learning abilities via a Hebb learning task. The SLI group showed impaired performance for the serial order reconstruction and recognition tasks, relative to language-matched and/or age-matched control groups. However, normal serial position effects were observed in all SLI children in the serial order reconstruction task, suggesting normal coding of serial position information. Similarly, performance on the Hebb serial learning task was at chronological age appropriate levels. Experiment 3 showed that the group differences observed for the serial order STM tasks in Experiment 1 disappeared when the SLI group was compared to a mental age-matched control group. Experiment 4 showed similar performance levels in the SLI group and the mental age-matched control group for a nonword recognition task assessing item STM capacities. This study shows that children with SLI have no specific impairments for serial order and item STM components but that poorer general cognitive efficiency is related to functional limitations in verbal STM tasks. The data are in line with limited information processing accounts of SLI. 相似文献
7.
Robert J. Hitzemann Jack Hirschowitz David L. Garver 《Journal of affective disorders》1986,10(3):227-232
Membrane order was measured in the erythrocyte ghost membranes of DSM-III schizophreniform disorder (SF), DSM-III schizophrenic (SCZ) and DSM-III manic (bipolar) (M) patients and a group of age- and sex-matched controls. Fluorescence polarization with the probe 1,6-diphenyl1-1,3,5-hexatriene was used to determine the steady-state fluorescence anisotropy (rs). The SF group showed a significant increase in rs (Δrs = 0.037) from the control group. Although the means were not significantly different, 3 of 8 Ms and 5 of 8 SCZs also had rs values > the highest control value. Thermotropic behavior of the membranes was evaluated over the range of 40 to 20°C. No difference among groups in membrane enthalpy was detected. Thus, the differences in rs appear to be associated with differences in entropy. Phosphatidylcholine (PC) levels, which were known to be abnormal in these patients, were compared with the rs values. A significant (P < 0.001, R= -0.63) linear correlation between rs and membrane PC levels was observed. Overall these data further support the view that unusual membrane biophysical factors may occur with high frequency in the psychoses and affective disorders. 相似文献
8.
We focus on the Fisher information matrix used for design evaluation and optimization in nonlinear mixed effects multiple response models. We evaluate the appropriateness of its expression computed by linearization as proposed for a single response model. Using a pharmacokinetic–pharmacodynamic (PKPD) example, we first compare the computation of the Fisher information matrix with approximation to one derived from the observed matrix on a large simulation using the stochastic approximation expectation–maximization algorithm (SAEM). The expression of the Fisher information matrix for multiple responses is also evaluated by comparison with the empirical information obtained through a replicated simulation study using the first‐order linearization estimation methods implemented in the NONMEM software (first‐order (FO), first‐order conditional estimate (FOCE)) and the SAEM algorithm in the MONOLIX software. The predicted errors given by the approximated information matrix are close to those given by the information matrix obtained without linearization using SAEM and to the empirical ones obtained with FOCE and SAEM. The simulation study also illustrates the accuracy of both FOCE and SAEM estimation algorithms when jointly modelling multiple responses and the major limitations of the FO method. This study highlights the appropriateness of the approximated Fisher information matrix for multiple responses, which is implemented in PFIM 3.0, an extension of the R function PFIM dedicated to design evaluation and optimization. It also emphasizes the use of this computing tool for designing population multiple response studies, as for instance in PKPD studies or in PK studies including the modelling of the PK of a drug and its active metabolite. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
9.
D Wasserman 《Acta psychiatrica Scandinavica》1989,79(5):460-467
A total of 88 interviews were conducted with 40 people attempting suicide who were receiving care in an intensive-care unit, and 129 interviews were carried out with their relatives and friends. The subjects were divided into 3 diagnostic groups: neurosis (n = 14), abuse (n = 19) and psychosis (n = 7). The incidence of relatives' failure to provide care after the suicide attempt--turning-away reactions as well as do not resuscitate orders, a form of passive euthanasia--was investigated. In 8 cases, partners of patients in the abuse and neurosis groups showed turning-away reactions. In 2 cases, relatives of elderly patients in the neurosis group said to the doctor that life-preserving measures should not be taken. Relatives explained their behaviour by saying that they had the best interests of the suicidal individual at heart. In-depth interviews, however, revealed that these reactions were a manifestation of the relatives own psychic conflicts, brought forth by the confrontation with the depressed and suicidal patient. Turning-away reactions and do not resuscitate orders might be interpreted as expressing the relatives' aggressiveness towards the suicidal individual and attempts to escape from a difficult situation. It is important that doctors stand up for the interests of suicidal people, which at times may conflict with relatives' interests, and help the relatives to sort out their problems and wishes with respect to the problem areas of passive euthanasia. 相似文献
10.
诱发电位的提取是脑电信号处理领域的前沿课题近年来 ,通过少次甚至单次试验提取诱发电位已经成为研究的主流。本文对近年来提取诱发电位的信号处理方法进行了简要的回顾 ,并分别从小波变换、神经网络、高阶累积量、独立分量分析等四个方面对算法进行了介绍 相似文献