Influence of arm positions on EMG-reaction time of the biceps brachii for elbow flexion and forearm supination

The influence of starting positions of the arm on EMG-RTs of the biceps brachii muscle for elbow flexion and forearm supination was examined using 16 normal subjects. Two angles of the elbow joint, 45 degrees and 110 degrees flexion, and two positions of the forearm, 45 degrees supination and 90 degrees pronation, were used as the factorial combinations of all four. The EMG-RT for elbow flexion decreased in the order of 110 degrees Pronation greater than 45 degrees Pronation = 110 degrees Supination greater than 45 degrees Supination, and that for forearm supination decreased in the order of 45 degrees Supination greater than 45 degrees Pronation = 110 degrees Supination greater than 110 degrees Pronation. These results were kinesiologically interpreted that variations of EMG-RTs were based on the change in the number of synergic muscles participating in an intended movement and the muscle length of the prime mover at the start of the movement.     

Sequence of preparatory set for response movement

Electromyographic reaction times (EMG-RTs) of the right biceps brachii muscle were examined for two movement patterns, elbow flexion and forearm supination, in 8 healthy male subjects under simple and complex RT conditions with varied preparatory intervals (PIs): 0, 200, 400, 600, and 800 msec. In the simple RT condition, the subject was informed of the movement patterns to be performed prior to beginning the trials. In the complex RT condition the subject had to choose one of the two movement patterns at the time of the presentation of a warning signal. The results indicated that: (1) compared with the simple RT condition a delay of about 100 msec. in over-all mean EMG-RT was observed at PI = 0 msec. in the complex RT condition; (2) the difference of over-all mean EMG-RT between the two RT conditions disappeared when PI = 400 msec.; and (3) the difference in EMG-RTs between flexion and supination in the complex RT condition became the same as that in the simple RT condition when PI = 700 msec. It is assumed that the preparatory set for response movements is organized in an order, resulting in the differentiation of RT.     

Disturbances of rhythm formation in patients with Parkinson's disease: part II. a forced oscillation model

The origin of the characteristic disturbances of rhythm formation in patients with Parkinson's disease (the hastening phenomenon) was discussed, using a second-order system of the periodic response. The input signal was regarded as a pulse series of a Dirac function. The output process of the system had maximal errors of response at input frequencies of f = omega0/n (n = 1, 2, . . .), where omega0 was the intrinsic frequency of the system. Damping coefficient epsilon represented a function of an inhibitor against these maximal errors and the errors diverged to infinity when epsilon = 0. The solution of this forced oscillation system indicated that the intrinsic oscillation of the system has a possibility to be excited at these critical frequencies f = omega/n. Inferred from data on the tapping test, the frequency of an intrinsic oscillation was 5 Hz in the central nervous system, then the critical frequencies were predicted 5/n = 5, 2.5, . . . Hz. On the tapping test the errors of response become maximum around 2.5 and 5 Hz (taps per second), and their peak heights increased from the minimum in well trained normal subjects to the maximum in patients. An inhibitory mechanism against the maximal error would function well, i.e. epsilon greater than 0, in normal subjects but so insufficiently (epsilon leads to 0) in patients that the excited intrinsic oscillation would control their response directly. Thus some patients could no longer maintain a synchronous tapping response at 2.5 Hz or 5 Hz and showed a hastened tapping of 5 6 Hz independent of the signal frequency.     

Cross-cultural Differences in Self-reported Decision-making Style and Confidence

The Melbourne Decision Making Questionnaire (Mann, Burnett, Radford, & Ford, 1997) measures self-reported decision-making coping patterns. The questionnaire was administered to samples of University students in the US (N = 475), Australia (N = 262), New Zealand (N = 260), Japan (N = 359), Hong Kong (N = 281), and Taiwan (N = 414). As predicted, students from the three Western, individualistic cultures (US, Australia, and New Zealand) were more confident of their decision-making ability than students from the three East Asian, group-oriented cultures (Japan, Hong Kong, Taiwan). No cross-cultural differences were found in scores on decision vigilance (a careful decision-making style). However, compared with Western students, the Asian students tended to score higher on buck-passing and procrastination (avoidant styles of decision making) as well as hypervigilance (a panicky style of decision making). Japanese students scored lowest on decision self-esteem and highest on procrastination and hypervigilance. It was argued that the conflict model and its attendant coping patterns is relevant for describing and comparing decision making in both Western and Asian cultures.     

Overdistribution in source memory

Semantic false memories are confounded with a second type of error, overdistribution, in which items are attributed to contradictory episodic states. Overdistribution errors have proved to be more common than false memories when the 2 are disentangled. We investigated whether overdistribution is prevalent in another classic false memory paradigm: source monitoring. It is. Conventional false memory responses (source misattributions) were predominantly overdistribution errors, but unlike semantic false memory, overdistribution also accounted for more than half of true memory responses (correct source attributions). Experimental control of overdistribution was achieved via a series of manipulations that affected either recollection of contextual details or item memory (concreteness, frequency, list order, number of presentation contexts, and individual differences in verbatim memory). A theoretical model was used to analyze the data (conjoint process dissociation) that predicts that (a) overdistribution is directly proportional to item memory but inversely proportional to recollection and (b) item memory is not a necessary precondition for recollection of contextual details. The results were consistent with both predictions.     

Elevation and mentoring: An experimental assessment of causal relations

Mentoring is a prosocial behavior in which an experienced person guides someone with less experience. Elevation refers to the responses elicited when a person witnesses others upholding the highest standards of moral virtue. Three experimental studies bring these two domains together. For all three studies, participants were randomly assigned to either read a story of someone exhibiting moral excellence or to a control condition. Participants in the elevation condition reported feeling more elevated, more positive attitudes toward mentoring, less negative attitudes toward mentoring, greater intentions to become a mentor (Study 1); an increased proclivity to gather information about becoming a mentor (Study 2a); and, an increased tendency to engage in mentoring directly via submitting advice to students (Study 2b). In their totality, the current studies link another prosocial outcome with elevation and demonstrate a condition under which individuals are more likely to be motivated to become a mentor.     

Microstructure and mechanical properties of Mg–8Al alloy fabricated by room-temperature multi-directional forging

As-extruded Mg–Al alloy was multi-directionally forged (MDFed) at room temperature to cumulative strain of ΣΔ??=?2.0 at maximum by employing a pass strain of Δ??=?0.1. The coarse initial grains were subdivided gradually to ultra-fine ones by mechanical twinning. The MDFed Mg alloy showed superior mechanical properties of 530?MPa yield and 650?MPa ultimate tensile strengths with ductility of 9%. The relatively large ductility was induced by grain orientation randomization due to multiple twinning and the small pass strains which suppressed the sharp basal-texture evolution.     

Electron spin resonance of hydrogenated amorphous silicon-carbon alloy films prepared by magnetron sputtering

Abstract

New electron spin resonance (ESR) lines with g¹ = 2·0017 and g₂ and g₃ = 2·0006 have been found in the ESR spectra of as-deposited a-Si_1–x C_x:H films prepared by magnetron sputtering of silicon in the gas mixtures of methane and argon. Similarities between the observed spectra and those for the E′ centre in glassy SiO₂ are discussed.     

A Psychometric Analysis of the Revised Child Anxiety and Depression Scale—Parent Version in a Clinical Sample

The Revised Child Anxiety and Depression Scale—Parent Version (RCADS-P) is a 47-item parent-report questionnaire of youth anxiety and depression, with scales corresponding to the DSM-IV categories of Separation Anxiety Disorder, Social Phobia, Generalized Anxiety Disorder (GAD), Panic Disorder, Obsessive-Compulsive Disorder, and Major Depressive Disorder (MDD). The RCADS-P is currently the only parent-report questionnaire that concurrently assesses youth symptomatology of individual anxiety disorders as well as depression in accordance with DSM-IV nosology. The present study examined the psychometric properties of the RCADS-P in a large (N = 490), clinic-referred sample of youths. The RCADS-P demonstrated favorable psychometric properties, including high internal consistency, convergent/divergent validity, as well as strong discriminant validity—evidencing an ability to discriminate between anxiety and depressive disorders, as well as between the targeted anxiety disorders. Support for the DSM-related six-factor RCADS-P structure was also evidenced. This structure demonstrated superior fit to a recently suggested alternative to the DSM-IV classification of anxiety and affective disorders—namely, the MDD/GAD “distress” factor.