略论《维摩诘经》净土思想

<维摩诘经>是印度早期大乘佛教的重要经典,在南北朝和隋唐时期广为流传,在佛教般若思想的发展中占有重要地位.该经蕴含着丰富的净土思想,明确提出了"心净则佛土净"这一著名命题.本文从菩萨取净土之目的与方法的角度,认为<维摩诘经>中菩萨取净土的目的是度化调伏众生,此即为"众生之类是菩萨佛土"的内含意蕴,还阐述分析了建立净佛国土之净土行和"心净则佛土净"思想.     

Efficient visual search without top-down or bottom-up guidance

Two types of mechanisms have dominated theoretical accounts of efficient visual search. The first are bottom-up processes related to the characteristics of retinotopic feature maps. The second are top-down mechanisms related to feature selection. To expose the potential involvement of other mechanisms, we introduce a new search paradigm whereby a target is defined only in a context-dependent manner by multiple conjunctions of feature dimensions. Because targets in a multiconjunction task cannot be distinguished from distractors either by bottom-up guidance or top-down guidance, current theories of visual search predict inefficient search. While inefficient search does occur for the multiple conjunctions of orientation with color or luminance, we find efficient search for multiple conjunctions of luminance/size, luminance/shape, and luminance/topology. We also show that repeated presentations of either targets or a set of distractors result in much faster performance and that bottom-up feature extraction and top-down selection cannot account for efficient search on their own. In light of this, we discuss the possible role of perceptual organization in visual search. Furthermore, multiconjunction search could provide a new method for investigating perceptual grouping in visual search.     

李伯元的"功名"与选择

自鲁迅以来,国内学界一直以为李伯元是个普通秀才,围绕着他是否因"屡举不第"而意见分歧.本文查证李伯元的功名其实是廪贡生.他只要愿意,凭廪贡生的功名就能出仕.但他放弃了科举之途和向官场发展的机会,选择了"下海"办报,成为晚清市民报人作家的先驱.     

Activation of group II metabotropic glutamate receptors induces depotentiation in amygdala slices and reduces fear-potentiated startle in rats

There is a close correlation between long-term potentiation (LTP) in the synapses of lateral amygdala (LA) and fear conditioning in animals. We predict that reversal of LTP (depotentiation) in this area of the brain may ameliorate conditioned fear. Activation of group II metabotropic glutamate receptors (mGluR II) with DCG-IV induces depotentiation in the LA. The induction of depotentiation is independent of NMDA receptors, L-type Ca++ channels, and calcineurin activity, but requires presynaptic activity and extracellular Ca++. (2S,2'R,3'R)-2-(2',3'-dicarboxycyclopropyl)glycine (DCG-IV) depotentiation is accompanied by a decrease in the frequency but not the amplitude of miniature excitatory post-synaptic currents (mEPSCs) and could be mimicked by endogenously released glutamate. DCG-IV inhibited the release of glutamate evoked by 4-AP but not that evoked by ionomycin, suggesting that the effect of DCG-IV is not mediated by an action downstream of Ca++ entry. Intra-amygdala infusion of mGluR II agonist blocks the consolidation of fear memory measured with fear-potentiated startle. Taken together, the present results characterize the properties of DCG-IV depotentiation and reveal a close parallel between depotentiation in the amygdala slice and the reduction of conditioned fear in animals.     

Improving measurement precision of test batteries using multidimensional item response models

A conventional way to analyze item responses in multiple tests is to apply unidimensional item response models separately, one test at a time. This unidimensional approach, which ignores the correlations between latent traits, yields imprecise measures when tests are short. To resolve this problem, one can use multidimensional item response models that use correlations between latent traits to improve measurement precision of individual latent traits. The improvements are demonstrated using 2 empirical examples. It appears that the multidimensional approach improves measurement precision substantially, especially when tests are short and the number of tests is large. To achieve the same measurement precision, the multidimensional approach needs less than half of the comparable items required for the unidimensional approach.     

The Simon effect with wheel-rotation responses

The authors examined clockwise and counterclockwise wheel-rotation responses to high- or low-pitched tones presented in participants' (N = 96, Experiment 1; N = 48, Experiment 2; N = 48, Experiment 3) left and right ears. In Experiment 1, a Simon effect (fastest responding when tone location and direction of wheel turn corresponded) was obtained when participants' hands were at the top or middle of the wheel but not at the bottom. With the bottom hand placement, a Simon effect was induced by instructions emphasizing hand movements but not by instructions emphasizing wheel movements (Experiment 2), and by a visual cursor controlled by the wheel but not one triggered by the response (Experiment 3). The results of the experiments showed that the nature of the task and the instructed action goal influence the direction of the Simon effect.     

Depression and vulnerability as assessed by the Rorschach method

We examined clinically depressed (CD; n = 16), previously depressed (PD; n = 19) and never depressed (ND; n = 18) individuals on 13 theoretically selected Rorschach (Exner, 1993; Rorschach, 1942) variables and on the Beck Depression Inventory (BDI; Beck, Rush, Shaw, & Emery, 1979). The group assignment was made according to the criteria of Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994). We tested 2 contradictory models for depressive vulnerability, Beck's (Clark & Beck, 1999) and Miranda and Persons's (1988; Persons & Miranda, 1992), in a planned comparison design with focused contrasts. The CDs significantly contrasted the combined group of NDs and the PDs in a pathological direction on 8 of the 13 Rorschach variables and on the BDI. However, the combined group of CDs and PDs also significantly contrasted the NDs in a pathological direction on 3 of these Rorschach variables and on the BDI. In addition, logistic regression analyses indicated that Rorschach indexes significantly improved the prediction of major depression above and beyond that achieved by the BDI. The findings show that the Rorschach method was able to identify (a) cognitive and aggressive disturbances that are present in individuals who are actively depressed but not in individuals who have been depressed in the past or never been depressed and (b) affective and coping disturbances that are present in depressed individuals and to some degree in PD individuals but not in individuals who have not experienced depression. We discuss the scanty evidence of psychological disturbances in PD individuals, as measured with the Rorschach, in relation to the mood-state dependent hypothesis of Miranda and Persons (1988; Persons & Miranda, 1992).     

外表真实区别、表征变化和错误信念的任务分析

自20世纪80年代以来,“心理理论”已成为发展心理学的研究热点和最活跃、最多产的领域。为了分析和比较“心理理论”的实验任务,该研究以济南市3所幼儿园中的233名3—6岁儿童为有效被试。进行了“意外转移。和“欺骗外表”两种心理理论实验任务。得出如下主要结论：(1)意外转移任务中内隐错误信念显著难于标准错误信念,易化错误信念与标准错误信念的难度不存在显著差异。(2)欺骗外表任务中外表真实区别难度显著低于表征变化和错误信念。(3)意外转移任务的错误信念显著难于欺骗外表任务的错误信念。     

元音和复合声识别中噪声分离机制的实验研究

该文用配对比较方法,从夫调谐波的数量对谐波筛的影响（实验一）、失调谐波的位置（实验二）以及谐波相位与其失调幅度之间的相互作用（实验三）等三个方面对失调谐波的分离机制进行探讨。研究结果表明：（1）多个谐波同时失调时其失调效应要比单个谐波强,即谐波失调存在累积效应;（2）谐波次数不同,其失调效应也存在差异,这种差异与谐波和共振峰之间的距离有关,谐波越靠近共振峰,其失调效应越明显,但对由等振幅的谐波系列构成的复合声而言,高次谐波的失调效应比低次谐波弱;（3）谐波相位对其失调效应产生间接影响,这种影响与谐波的起始振幅有关,当相位为π／2和3π／2时,失调效应更加明显。