Phonon driven transport in amorphous semiconductors: Transition probabilities

Inspired by Holstein's work on small polaron hopping, the evolution equations of localized states and extended states in presence of atomic vibrations are derived for an amorphous semiconductor. The transition probabilities are obtained for four types of transitions: from one localized state to another localized state, from a localized state to an extended state, from an extended state to a localized state, and from one extended state to another extended state. At a temperature not too low, any process involving localized state is activated. The computed mobility of the transitions between localized states agrees with the observed `hopping mobility'. We suggest that the observed `drift mobility' originates from the transitions from localized states to extended states. Analysis of the transition probability from an extended state to a localized state suggests that there exists a short-lifetime belt of extended states inside conduction band or valence band. It agrees with the fact that photoluminescence lifetime decreases with frequency in a-Si/SiO$_{2}$ quantum well while photoluminescence lifetime is not sensitive to frequency in c-Si/SiO$_{2}$ structure.Comment: 41 pages, 3 figures, submitted to Phys. Rev.

Improving adherence and effectiveness of computerised cognitive behavioural therapy without support for depression: A qualitative study on patient experiences

Background: Several studies have evaluated the efficacy and effectiveness of computerized cognitive behavioural therapy (CCBT) for depression, but research on the patient perspective is limited. Aims: To gain knowledge on patient experiences with the online self-help CCBT program Colour Your Life (CYL) for depression, and find explanations for the low treatment adherence and effectiveness. Method: Qualitative data were collected through semi-structured interviews with 18 patients. Interviewees were selected from a CCBT trial. An inductive, content analysis of the interviews was performed. Results: The main theme throughout the interviews concerns barriers and motivators experienced with CCBT. The most important barriers included experiences of a lack of identification with and applicability of CCBT-CYL, lack of support to adhere with the program or to gain deeper understanding, and inadequate computer/Internet skills, equipment, or location. Confusion between CCBT and Internet questionnaires resulted in no CCBT uptake of some study participants. Motivators included experiencing self-identification and improvement through CCBT-CYL, participating in a scientific study, and the freedom and anonymity associated with online computer self-help. The addition of support to CCBT was suggested as an improvement towards adherence and the course content. Conclusion: The CCBT program CYL in its current form does not work for a large group of people with depressive symptoms. More tailoring, the provision of support (professional or lay) and good computer conditions could improve CCBT

Topological dynamics of an intrinsically disordered N‐terminal domain of the human androgen receptor

Analytical BioScience