The Meaning of Prakṛti in the Yogasūtra and Vyāsabhāṣya

It is a common mistake, especially, perhaps, among students of the religions and philosophies of India, to assume that the word prak?ti, best known as the ultimate material principle in the Sā?khya and Yoga systems of religious thought, the material cause of the world in Hindu theologies and, as such, an epithet of the goddesses in Hinduism, always refers to an ultimate principle. Even in Sā?khya and Yoga texts the word prak?ti is used in various ways. Prak?ti does not always refer to the ultimate principle. Translators often leave the word prak?ti untranslated and mislead the reader to assume that the ultimate principle is referred to, when it is not. This article discusses the use of prak?ti in the Sā?khya-Yoga texts the Yogasūtra and the Vyāsabhā?ya and criticises some translation practices.     

Positive schizotypal symptoms predict treatment outcome in obsessive-compulsive disorder

Previous research has suggested that the presence of schizotypal personality disorder may represent a risk factor for treatment failure in obsessive-compulsive disorder (OCD). Relying on a dimensional approach, the present study investigated whether the predictive importance of schizotypal personality is shared by all of its features to the same extent or whether it is confined to a subset of symptoms. Fifty-three patients underwent multi-modal cognitive-behavioral therapy with or without adjunctive antidepressive medication. Therapy response was defined as a 35% decline of the Y-BOCS total score. At baseline assessment, patients were asked to fill out the schizotypal personality questionnaire, the perceptual aberration scale and the Beck depression inventory. Stepwise regression analysis and group comparisons conducted with the schizotypal and depression scales revealed that elevated scores in the positive schizotypal scales, especially perceptual aberrations, were highly predictive for treatment failure. Responders to treatment and non-responders did not significantly differ on other variables or on scores in two scales which measured response biases. The study provides evidence that positive schizotypal symptoms are antecendents for treatment failure in OCD. It needs to be evaluated whether these at-risk individuals benefit from additional intervention, such as the adminstration of low-dose atypical neuroleptics and specifically tailored behavorial intervention.     

Pre-attentive auditory processing of lexicality

The effects of lexicality on auditory change detection based on auditory sensory memory representations were investigated by presenting oddball sequences of repeatedly presented stimuli, while participants ignored the auditory stimuli. In a cross-linguistic study of Hungarian and German participants, stimulus sequences were composed of words that were language-familiar, lexical, meaningful in Hungarian but language-unfamiliar, not lexical, meaningless in German, and words with the opposite characteristics. The roles of frequently presented stimuli (Standards) and infrequently presented one (Deviants) were fully crossed. Language-familiar and language-unfamiliar Deviants elicited the Mismatch Negativity component of the event-related brain potential. We found differences in processes of change detection depending on whether the Standard was language-familiar, or not. Whereas, the lexicality of the Deviant had no effect on the processes of change detection. Also, language-familiar Standards processed differently than language-unfamiliar ones. We suggest that pre-attentive (default) tuning to meaningful words sets up language-specific preparatory processes that affect change detection in speech sequences.     

Atomistic simulations of cross-slip of jogged screw dislocations in copper

We have performed atomic-scale simulations of cross-slip processes of screw dislocations in copper, simulating jog-free dislocations as well as different types of jogged screw dislocations. Minimum-energy paths and corresponding transition state energies are obtained using the nudged-elastic-band path technique. We find low barriers and effective masses for the conservative motion along the dislocations of elementary jogs on both ordinary {111}<110> and nonoctahedral {110}<110> slip systems. The jogs are found to be constricted and therefore effectively act as pre-existing constrictions; the cross-slip activation energy is thereby dramatically reduced, yielding values in agreement with experiment.     

Discrimination of personally significant from nonsignificant sounds: A training study

Discriminating personally significant from nonsignificant sounds is of high behavioral relevance and appears to be performed effortlessly outside of the focus of attention. Although there is no doubt that we automatically monitor our auditory environment for unexpected, and hence potentially significant, events, the characteristics of detection mechanisms based on individual memory schemata have been far less explored. The experiments in the present study were designed to measure event-related potentials (ERPs) sensitive to the discrimination of personally significant and nonsignificant nonlinguistic sounds. Participants were presented with random sequences of acoustically variable sounds, one of which was associated with personal significance for each of the participants. In Experiment 1, each participant’s own mobile SMS ringtone served as his or her significant sound. In Experiment 2, a nonsignificant sound was instead trained to become personally significant to each participant over a period of one month. ERPs revealed differential processing of personally significant and nonsignificant sounds from about 200 ms after stimulus onset, even when the sounds were task-irrelevant. We propose the existence of a mechanism for the detection of significant sounds that does not rely on the detection of acoustic deviation. From a comparison of the results from our active- and passive-listening conditions, this discriminative process based on individual memory schemata seems to be obligatory, whereas the impact of individual memory schemata on further stages of auditory processing may require top-down guidance.     

Conflict-induced perceptual filtering

In a variety of conflict paradigms, target and distractor stimuli are defined in terms of perceptual features. Interference evoked by distractor stimuli tends to be reduced when the ratio of congruent to incongruent trials is decreased, suggesting conflict-induced perceptual filtering (i.e., adjusting the processing weights assigned to stimuli associated with the target and with the distractor features). In search of evidence for such a mechanism, we administered a flanker task, in which targets and distractors were defined in terms of stimulus location (Experiment 1) or color (Experiment 2). The efficiency of processing stimuli associated with target and distractor features was assessed in intermixed trials of a visual search task, in which a target had to be detected irrespective of these features. In both experiments search times were shorter for stimuli associated with the target feature than with the distractor feature of the flanker task. This effect was increased under conditions of a reduced congruent/incongruent ratio, thereby providing evidence for conflict-dependent perceptual filtering.