再谈十字军东侵

5年前,应《科学与无神论》杂志编辑部之约,我谈了十字军东侵的经过。今天我准备再谈谈它的原因、后果及对后世的深远影响。一、十字军东侵的起因十字军东侵的起因是多方面的,主要有以下几点:一是当时西欧封建主迫切要求新的领地和资源。他们从领地上的剥削所得,已经不能满足自己的欲望,希望得到东方的财富,因而积极支持十字军东侵活动。二是无领地的骑士收入微薄,往往债台高筑,依靠服军役和打劫商旅为生。因此他们把目光投向东方,希冀到那里去发财致富。三是西欧城市商人,特别是意大利的商人,热衷于十字军的东侵。他们为了商业利益,希望夺取…     

On the role of visual afferent information for the control of aiming movements toward targets of different sizes

The authors investigated (a). whether the specificity of practice hypothesis is mediated by the importance of visual afferent information for the control of manual aiming movements and (b). how movement planning and online correction processes to the movement initial impulse are affected by the withdrawal of visual information in transfer. In acquisition, participants (N = 40) aimed at targets of different sizes in a full-vision or in a target-only condition before being transferred to a target-only condition without knowledge of results. The results supported the hypothesis that learning is specific to the source or sources of afferent information that are more likely to ensure optimal performance. The results also suggested that individuals will not always use visual afferent information more extensively when aiming at a small rather than at a large target. Instead, in a temporally constrained task, the relative efficiency of visually based corrections appears to mediate how exclusively an individual will rely on online visual afferent information for movement control. Finally, the detailed kinematic analysis performed in the present study clearly indicated that online modifications to the movement primary impulse are possible, arguing for a continuous or pseudo-continuous control of relatively slow aiming movements on the basis of visual afferent input.     

Brains that are out of tune but in time

It is estimated that about 4% of the general population may have amusia (or tone deafness). Congenital amusia is a lifelong disability for processing music despite normal intellectual, memory, and language skills. Here we present evidence that the disorder stems from a deficit in fine-grained pitch perception. Amusic and control adults were presented with monotonic and isochronous sequences of five tones (i.e., constant pitch and intertone interval). They were required to detect when the fourth tone was displaced in pitch or time. All amusic participants were impaired in detecting the pitch changes, and showed no sign of improvement with practice. In contrast, they detected time changes as well as control adults and exhibited similar improvements with practice. Thus, the degraded pitch perception seen in the amusic individuals cannot be ascribed to nonspecific problems with the task or to poor hearing in general. Rather, the data point to the presence of a congenital neural anomaly that selectively impairs pitch processing.     

Predictable postural perturbation in premotor and motor components of reaction time

The aim of the present experiment was to study the central control of posture and movement coordination. Subjects' task was voluntarily to raise their arms in response to a visual signal, this movement generating an unloading in which the weight of the load (0 gm, 1500 gm, 3000 gm, or 4500 gm) was known in advance. Thus, subjects could predict the postural perturbation generated by the unloading. Analysis showed an effect of the unloading conditions: in the 0-gm and 1500-gm conditions, reaction time (RT) was longer than in the 3000-gm and 4500-gm conditions. This decrease in RT was exclusively due to a reduction of the premotor time, confirming the posturokinetic coordination in the programming processes. The implications of the decrease in premotor time with the increase of the perturbation for the posture/movement coordination strategies are also discussed.     

Impaired processing of prosodic and musical patterns after right hemisphere damage

The distinction between the processing of musical information and segmental speech information (i.e., consonants and vowels) has been much explored. In contrast, the relationship between the processing of music and prosodic speech information (e.g., intonation) has been largely ignored. We report an assessment of prosodic perception for an amateur musician, KB, who became amusic following a right-hemisphere stroke. Relative to matched controls, KB's segmental speech perception was preserved. However, KB was unable to discriminate pitch or rhythm patterns in linguistic or musical stimuli. He was also impaired on prosodic perception tasks (e.g., discriminating statements from questions). Results are discussed in terms of common neural mechanisms that may underlie the processing of some aspects of both music and speech prosody.     

A differing bidirectional impact on the recognition accuracy of facial expression

This study explored a bidirectional impact on the recognition accuracy of various facial expressions deriving from both the observer and sender in a sample of Chinese participants. A facial manipulation task was used to examine the ability of an observer's facial feedback to modulate the recognition of various facial expressions. Furthermore, the effect of a sender's facial expression with an open or closed mouth on recognition accuracy was investigated. The results showed that only recognition accuracy of a sad facial expression was influenced simultaneously by bidirectional sources from a sender and observer. Moreover, the impact of the unidirectional cue of a sender's facial feature (i.e., mouth openness) on happy and neutral faces was found to influence the recognition accuracy of these faces, but not the observer's bodily state. These findings indicate that the bidirectional impact derived from an observer and sender on facial expression recognition accuracy differs for emotional and neutral expressions.     

当代大学生创业意向影响因素研究

为了深入了解当代大学生的创业意向及其影响因素,研究者以全国30所高校5000多名大学生为被试,对影响大学生创业意向的诸多因素进行了分析。研究发现:当代大学生的创业意向在性别、奖学金获得次数、学生干部经历、出生地上均存在一定差异。大学生主客观条件中的性别、学校性质、创业兴趣、创意能力改善对创业意向有显著影响。创业教育和创业环境认知的引入对于预测大学生的创业意向均有增量效度,能够在个体的主客观条件以外解释个体创业意向的变异。在大学生认知中,影响创业成功的因素主要由客观背景资源、主观能力经验和外部宏观环境3个因子组成,其中主观能力经验的作用排在首位。     

《管子》对《淮南子》的影响

《管子》对《淮南子》的影响,体现在文本和思想两个方面。《淮南子》中,既有对《管子》文本的袭用,也有对《管子》思想的继承。这与汉初的社会思潮和该书的编撰意图有关,也与淮南王刘安门下聚集了一部分来自齐地的学者有直接关系。     

Neural functions of calcineurin in synaptic plasticity and memory

Major brain functions depend on neuronal processes that favor the plasticity of neuronal circuits while at the same time maintaining their stability. The mechanisms that regulate brain plasticity are complex and engage multiple cascades of molecular components that modulate synaptic efficacy. Protein kinases (PKs) and phosphatases (PPs) are among the most important of these components that act as positive and negative regulators of neuronal signaling and plasticity, respectively. In these cascades, the PP protein phosphatase 2B or calcineurin (CaN) is of particular interest because it is the only Ca(2+)-activated PP in the brain and a major regulator of key proteins essential for synaptic transmission and neuronal excitability. This review describes the primary properties of CaN and illustrates its functions and modes of action by focusing on several representative targets, in particular glutamate receptors, striatal enriched protein phosphatase (STEP), and neuromodulin (GAP43), and their functional significance for synaptic plasticity and memory.     

Elaboration et validation de tests de jugement situationnel comme outil de sélection professionnelle : guide méthodologique

Current views in personnel selection recognize the necessity for situational judgements tests (SJT) which are closed to the real work context of companies. The SJTs have also become a popular selection tool across Europe. SJTs are attractive because they show good validity, positive applicants reactions and can be cost effective to test large group of applicants at once. The aim of this paper is to describe a structured methodology for the elaboration of such test. Each stage is illustrated by examples and psychometrics validation issues are discussed.