Interpretation of the low-temperature photoconductivity in a-Si

Abstract

The paper is concerned with the interpretation of steady-state photoconductivity results on undoped a-Si at temperatures of 50K and below which lead to an essentially constant value of the (photogeneration efficiency x mobility x lifetime) product νμτ?10^?11 cm² V^?1. Measurements on p⁺-i-n⁺ junctions and Cr-i-n⁺ barriers were carried out to determine the above parameters separately: (i) steadystate reverse saturation currents gave a generation efficiency of ν? 5×10-² below 50K, suggesting that geminate recombination limits the generation process. (ii) the electron drift mobility μ_e through the tail states and the charge extracted from the absorption region of the incident light were investigated by transient experiments, these showed that μ_eτ_a is limited to about 3×10^?10cm²V^?1 at low T. The independent results account for the observed νμτ values and suggest that, contrary to the interpretation of Hoheisel, Carius and Fuhs (1984), the main contribution to the low-temperature photoconductivity arises from transport in tail states.     

The effect of hydrogen plasma on the properties of a-Si:H/a-Si1-xNx:H superlattices

Abstract

A hydrogen plasma introduced during the interrupting interval when alternating two gases affects the properties of a-Si:H/a-Si_1-xN_x:H superlattices resulting in the creation of fewer interface defects than the superlattices prepared without the hydrogen plasma.     

Dependence and physical exercise: Spanish validation of the Exercise Dependence Scale-Revised (EDS-R)

The purpose of this study was to validate the Spanish version of the Exercise Dependence Scale-Revised (EDS-R). To achieve this goal, a sample of 531 sport center users was used and the psychometric properties of the EDS-R were examined through different analyses. The results supported both the first-order seven-factor model and the higher-order model (seven first-order factors and one second-order factor). The structure of both models was invariant across age. Correlations among the subscales indicated a related factor model, supporting construct validity of the scale. Alpha values over .70 (except for Reduction in Other Activities) and suitable levels of temporal stability were obtained. Users practicing more than three days per week had higher scores in all subscales than the group practicing with a frequency of three days or fewer. The findings of this study provided reliability and validity for the EDS-R in a Spanish context.     

Deflationism and the Dependence of Truth on Reality

A common objection against deflationism is that it cannot account for the fact that truth depends on reality. Consider the question ‘On what does the truth of the proposition that snow is white depend?’ An obvious answer is that it depends on whether snow is white. Now, consider what answer, if any, a deflationist can offer. The problem is as follows. A typical deflationary analysis of truth consists of biconditionals of the form ‘The proposition that p is true iff p’. Such biconditionals tell us nothing about what the truth of the proposition that p might depend on. Therefore, it seems that a typical deflationist cannot give an answer. Since we know that an answer is available, this throws doubt over the adequacy of deflationism as an account of truth. Articulated here is a defence of deflationism against this objection. It is argued that although biconditionals of the sort mentioned do not explicitly state a dependency between truth and reality, they nevertheless convey one. The reason is that, given the context in which a deflationist invokes the biconditionals, such a dependency is implicated. A potential problem with this defence is that it leaves the deflationist still unable to give an account of what it is for truth to depend on reality. One might think that a deflationist can offer such an account by appealing to truthmaker theory but, it is argued below, truthmaker theory is unavailable to a deflationist. Instead, the deflationist should question the assumption that an account is available.     

依赖结构对信任行为的影响:基于互依理论的视角

信任是人际互动中的重要主题,受到诸多因素的影响,越来越多的研究者关注情境特征对信任的影响。以相互依赖理论为基础,操作依赖的相互性、依赖水平和利益协同,构建互动双方间不同的依赖结构,分析不同依赖结构对被试信任的影响。结果表明:(1)在双向依赖情境中被试的信任水平显著高于单向依赖情境;(2)单向依赖、低利益协同情境中,依赖水平对个体的信任行为有显著影响,双向依赖、高利益协同情境中,依赖水平对个体信任行为的影响不显著;(3)单向依赖、低依赖水平情境中,利益协同对信任行为有显著影响,双向依赖、高利益协同情境中,利益协同对信任行为影响不显著。     

Neurocognitive impairments in boys on the life-course persistent antisocial path

This study addresses 5 unresolved issues in the neuropsychology of antisocial behavior using a community sample of 325 school boys in whom neurocognitive measures were assessed at age 16-17 years. Antisocial behavior measures collected from age 7-17 years were cluster analyzed and produced 4 groups: control, childhood-limited, adolescent-limited, and life-course persistent. Those on the lifecourse persistent path and also on the childhood-limited path were particularly impaired on spatial and memory functions. Impairments were independent of abuse, psychosocial adversity, head injury, and hyperactivity. Findings provide some support for the life-course persistent versus adolescent-limited theory of antisocial behavior and suggest that (a) neurocognitive impairments are profound and not artifactual and (b) childhood-limited antisocials may not be free of long-lasting functional impairment.     

Developmental Trajectories of Religious Service Attendance: Predictors of Nicotine Dependence and Alcohol Dependence/Abuse in Early Midlife

Journal of Religion and Health - This longitudinal study assesses the associations between developmental trajectories of religious service attendance from mean age 14 to mean age 43 and nicotine...     

Saccades to targets in three-dimensional space: Dependence of saccadic latency on target location

The latency of saccadic movements to targets appearing at various positions in three-dimensional visual space was measured in four experiments. The first experiment confirmed that latencies of saccades to visual targets are greater in the lower visual field and showed that the increase is not influenced by the vertical starting position of the eye in the orbit, nor by a time gap between the fixation offset and the target onset. A hypothesis that this visual field difference was caused by a link between downward saccades and convergence movements was tested by recording saccade latencies when the targets were in a different depth plane from that of the original fixation. We did not find any direct support for the vergence involvement hypothesis, although the lower/upper visual field effect was shown to decrease consistently in monocular viewing. It was also shown that saccades to targets positioned in a different depth plane have longer latencies. In a final experiment, the visual field effect was shown to depend on the egocentric rather than the gravitational vertical.     

More dead than dead: perceptions of persons in the persistent vegetative state

Patients in persistent vegetative state (PVS) may be biologically alive, but these experiments indicate that people see PVS as a state curiously more dead than dead. Experiment 1 found that PVS patients were perceived to have less mental capacity than the dead. Experiment 2 explained this effect as an outgrowth of afterlife beliefs, and the tendency to focus on the bodies of PVS patients at the expense of their minds. Experiment 3 found that PVS is also perceived as “worse” than death: people deem early death better than being in PVS. These studies suggest that people perceive the minds of PVS patients as less valuable than those of the dead – ironically, this effect is especially robust for those high in religiosity.     

Intermittent exposure to social defeat and open-field test in rats: acute and long-term effects on ECG,body temperature and physical activity

This study investigated the effects of exposure to an intermittent homotypic stressor on: (i) habituation of acute autonomic responsivity (i.e. cardiac sympathovagal balance and susceptibility to arrhythmias), and (ii) circadian rhythmicity of heart rate, body temperature, and physical activity. After implantation of a transmitter for the radiotelemetric recording of electrocardiogram (ECG), body temperature and physical activity, adult male rats (Rattus norvegicus, Wild Type Groningen strain) were repeatedly exposed (10 consecutive times, on alternate days) to either a social stressor (defeat by a con-specific, n = 15) or an open-field, control challenge (transfer to a new cage; n = 8). ECGs, body temperature and physical activity were continuously recorded in baseline, test and recovery periods (each lasting 15 min), at the 1st and 10th episodes of both defeat and open-field challenge. The circadian rhythms of heart rate, body temperature and physical activity were monitored before (5 days), during (16 days) and after (21 days) the intermittent stress protocol. This study indicates that there is no clear habituation of either acute cardiac autonomic responsivity (as estimated by means of time-domain indexes of heart rate variability) or arrhythmia occurrence to a brief, intermittent, homotypic challenge, regardless of the nature of the stressor (social or non-social). On the other hand, rats exposed to social challenge also failed to show adaptation of acute temperature and activity stress responsiveness, whereas rats facing open-field challenge developed habituation of activity and sensitization of temperature responses. Repeated social challenge produced remarkable reductions of the heart rate circadian rhythm amplitude (this effect being significantly greater than that produced by intermittent open-field), but only minor changes in the daily rhythms of body temperature and physical activity.     

Studies in Affective Reaction: II. Dependence of Affective Ratings upon the Stimulus-Situation

Meehl, Paul E. Clinical vs. Statistical Prediction: A Theoretical Analysis and Review of the Evidence. Minneapolis: Univ. Minnesota Press, 1954. Pp. 149. Reviewed by Henry Winthrop.     

Dependence of illusory motion on directional consistency in oblique components

Pinna and Brelstaff (2000 Vision Research 40 2091-2096) reported a motion illusion on viewing two concentric circles consisting of quadrangular components with black and white sides on a grey background. Our results suggest that the illusion is based on the integration of motion signals derived from oblique components, and on the consistency in the direction among those components. Furthermore, arrays of these oblique components can elicit the perception of motion not only for the oblique components themselves, but also for other objects in the picture. We propose that the motion illusion depends not only upon detection of the illusory motion signal at each local oblique component, but also upon the accumulation of the signal all over the stimulus configuration.     

Dependence of the overtraining extinction effect on attention to runway cues

Six groups of rats were given 60 extinction trials in a runway following 30, 90 or 120 acquisition trials. For half the groups, a hurdle was interposed in the runway during both acquisition and extinction. For rats tested with the hurdle, the 30-trial group extinguished more readily than the other two groups. With the hurdle absent, overtrained rats extinguished more readily. This was interpreted as supporting the hypothesis that overtraining transfers control of responding from external to internal cues, and that internally controlled running is relatively more susceptible to extinction.     

Dependence in the elderly from an interactional point of view: verbal and observational data

Dependence in the elderly was investigated from an interactional point of view. Observations as well as verbal data of the elderly and professional caregivers were considered. Samples consisted of 14 elderly people receiving regular home health care (M = 78.9, SD = 6.3 years) and 16 elderly people receiving regular nursing home care (M = 81.4, SD = 7.5 years). Results showed a strong tendency toward independence in the elderly. Sense of control in the self-care interactions observed was higher in the home health care group than in the group receiving nursing home care. Division of the elderly into subgroups with high, medium, and low perceived self-efficacy showed that the elderly high in self-efficacy were more independent in terms of observed self-care. Causal explanations of the elderly's competence and their nonuse of competence were significantly different between the elderly and staff.