Anomaly of the current self-oscillation frequency in the sequential tunneling of a doped GaAs/AlAs superlattice

An anomalous behavior of the current self-oscillation frequency is observed in the dynamic de voltage bands, emerging from each sawtoothlike branch of the current-voltage characteristic of a doped GaAs/A1As superlattice in the transition process from static to dynamic electric field domain formations. Varying the applied de voltage at a fixed temperature, we find that the frequency increases while the averaged current decreases. Inside each voltage band, the frequency has a strong voltage dependence in the temperature range where the averaged current changes with the applied de voltage. This dependence can be understood in terms of motion of the system along a limit cycle.

Negative differential resistance and the transition to current self-oscillation in GaAs/AlAs superlattices

We investigate the transition from static to dynamic electric field domains (EFDs) in a doped GaAs/AlAs superlattice (SL). We show that a transverse magnetic field and/or the temperature can induce current self-oscillations. This observation can be attributed to the negative differential resistance (NDR) effect. Transverse magnetic field and the temperature can increase the NDR of a doped SL. A large NDR can lead to an unstable EFD in a certain range of d.c. bias. (C) 1999 Elsevier Science Ltd. All rights reserved.

Current self-oscillation induced by a transverse magnetic field in a doped GaAs/AlAs superlattice

We investigate the influence of a transverse magnetic field on the current-voltage characteristics of a doped GaAs/AlAs superlattice at 1.6 K. The current transport regimes-stable electric field domain formation and current selfoscillation-are observed with increasing transverse magnetic field up to 13 T. Magnetic-field-induced redistribution of electron momentum and energy is identified as the mechanism triggering the switching over of one process to another lending to a change in the dependence of the effective electron drift velocity on electric field. Simulation yields excellent agreement with observed results.

Transverse magnetic field effect on the current hysteresis of doped GaAs/AlAs superlattice

The influence of a transverse magnetic field up to 13 T at 1.6 K on the current-voltage, I (V), characteristics of a doped GaAs/AlAs superlattice was investigated. Current hysteresis was observed in the domain formation regions of the I (V) at zero magnetic field while applied bias was swept in both up (0-6 V) and down (6-0 V) directions. The magnitude of current hysteresis was reduced and finally disappeared with increasing transverse magnetic field. The effect is explained as the modification of the current density versus electric field characteristic by transverse magnetic fields. Calculated results based on the tunnelling current formula in a superlattice support our interpretation.

Analysis of the temperature-induced transition to current self-oscillations in doped GaAs/AlAs superlattices

We observed the decrease of the hysteresis effect and the transition from the stable to the dynamic domain regime in doped superlattices with increasing temperature. The current-voltage characteristics and the behaviours of the domain boundary are dominated by the temperature-dependent lineshape of the electric field dependence of the drift velocity (V(F)), As the peak-valley ratio in the V(F) curve decreases with increasing temperature, the hysteresis will diminish and temporal current self-oscillations will occur. The simulated calculation, which takes the difference in V(F) curves into consideration, gives a good agreement with the experimental results.

Towards understanding self-development coaching programs

Self-development resources are a popular billion -dollar industry worldwide used to improve individuals quality of lives. However, there are insufficient studies for a contemporary conceptualization, especially when it comes to live self-development programs. This paper provides a literature review about current self-development definitions, ideology, concepts, and themes; quality of material provided; quality and characteristics of self-development providers; and the features of the participants who seek such programs. The paper will also discuss the relationsh ip between self-development and related disciplines including coaching, training, mentoring, and motivational speaking. Finally, a new definition will be proposed for self-development coaching programs. Gaps of knowledge are highlighted for further research.

Self-sustained oscillations caused by magnetic field in a weakly-coupled GaAs/AlAs superlattice

We have investigated the influence of transverse magnetic field B up to 14 T at 1.6 K on the tunneling processes of electric field domains in doped weakly coupled GaAs/AlAs superlattices. Three regimes, i.e, stable field domains, current self-sustained oscillations and averaged field distribution are successively observed with increasing B. The mechanisms of switching-over among these regimes are due to B-induced modification of the dependence of the effective electron drift velocity on electric field. The simulated calculation gives a good agreement with the observed experimental results. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

Self-sustained oscillations caused by magnetic field in a weakly-coupled GaAs/AlAs superlattice

We have investigated the influence of transverse magnetic field B up to 14 T at 1.6 K on the tunneling processes of electric field domains in doped weakly coupled GaAs/AlAs superlattices. Three regimes, i.e, stable field domains, current self-sustained oscillations and averaged field distribution are successively observed with increasing B. The mechanisms of switching-over among these regimes are due to B-induced modification of the dependence of the effective electron drift velocity on electric field. The simulated calculation gives a good agreement with the observed experimental results. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

Self-Management of Chronic Pain: Interventions, Strategies, Barriers, and Facilitators

Background & Purpose: Chronic pain is a prevalent chronic condition for which the best management options rarely provide complete relief. Individuals with chronic pain with neuropathic characteristics (NC) report more severe pain and experience less relief from interventions. Little is known about current self-management practices. The purpose of this dissertation was to inform self-management of chronic pain with and without NC at the individual, health system, and policy levels using the Innovative Care for Chronic Conditions Framework. Methods: The study included a systematic search and review and cross-sectional survey. The review evaluated the evidence for chronic pain self-management interventions and explored the role of health care providers in supporting self-management. The survey was mailed to 8,000 randomly selected Canadians in November 2011, and non-respondents were followed-up in May 2012. Screening questions were included for both chronic pain and NC. The questionnaire captured pain descriptions, self-management strategies, and self-management barriers, and facilitators. Results: Findings of the review suggested that self-management interventions are effective in improving pain and health outcomes. Health care professionals provided self-management advice and referred individuals to self-management interventions. The questionnaire was completed by 1,520 Canadians. Those with chronic pain (n=710) identified primary care physicians as the most helpful pain management professional. Overall, use of non-pharmaceutical medical self-management strategies was low. While use positive emotional self-management strategies was high, individuals with NC were more likely to use negative emotional self-management strategies compared to those without NC. Multiple self-management barriers and facilitators were identified, however those with NC were more likely than those without NC to experience low self-efficacy, depression and severe pain which may impair the ability to self-management. Conclusions: Health care professionals have the opportunity to improve chronic pain outcomes by providing self-management advice, referring to self-management interventions, and addressing self-management barriers and facilitators. Individuals with NC may require additional health services to address their greater self-management challenges, and further research is needed to identify non-pharmaceutical interventions effective in relieving chronic pain with NC. Public policy is needed to facilitate health systems in providing long-term self-management support for individuals with chronic pain.

Self-disclosure decision making based on intimacy and privacy

Autonomous agents may encapsulate their principals' personal data attributes. These attributes may be disclosed to other agents during agent interactions, producing a loss of privacy. Thus, agents need self-disclosure decision-making mechanisms to autonomously decide whether disclosing personal data attributes to other agents is acceptable or not. Current self-disclosure decision-making mechanisms consider the direct benefit and the privacy loss of disclosing an attribute. However, there are many situations in which the direct benefit of disclosing an attribute is a priori unknown. This is the case in human relationships, where the disclosure of personal data attributes plays a crucial role in their development. In this paper, we present self-disclosure decision-making mechanisms based on psychological findings regarding how humans disclose personal information in the building of their relationships. We experimentally demonstrate that, in most situations, agents following these decision-making mechanisms lose less privacy than agents that do not use them. (C) 2012 Elsevier Inc. All rights reserved.

An examination of the range of self-funding options available to regional galleries and an assessment of their suitability for use in those institutions

Researches the suitability of a variety of self-funding options available to regional galleries in Australia. An overview of the range of current self-funding practices is given. Each option is mapped according to its impact on core/value added services and its effect on primary/secondary users and assessed for suitability using these criteria.

Response of human pulps capped with a self-etching adhesive system

Objective: The aim of this study was to evaluate the human pulp response following direct pulp capping with a current self-etching bonding agent and calcium hydroxide (CH). Methods: Thirty-three sound human premolars had their pulp tissue mechanically exposed. Sterile distilled water was used to control the hemorrhage and exudation from the pulp exposure site. The pulps were capped with Clearfil Liner Bond 2 (CLB-2) or CH and the cavities were filled with a resin composite (Z-100) according to the manufacturer's instructions. After 5, 30 and 120-300 days, the teeth were extracted and processed for microscopic examination. Results: At short-term, CLB-2 elicited a mild to moderate inflammatory pulp response with dilated and congested blood vessels adjacent to pulp exposure site. With time, macrophages and giant cells engulfing globules and particulates of resinous material displaced into the pulp space were observed. This chronic inflammatory pulp response triggered by fragments of bonding agent displaced into the pulp space did not allow pulp repair interfering with the dentin bridging. On the other hand, pulps capped with CH exhibited an initial organization of elongated pulp cells underneath the coagulation necrosis. Pulp repair and complete dentin bridge formation was observed at long-term evaluation. Significance: The present study demonstrated that CH remains the pulp capping agent of choice for mechanically exposed human pulps. CLB-2 did not allow complete connective tissue repair adjacent to the pulp exposure site. Consequently, this bonding agent cannot be recommended for pulp therapy of sound human teeth. © 2001 Academy of Dental Materials. Published by Elsevier Science Ltd. All rights reserved.

Does Trauma Impair Self-Control? Differences in Delaying Gratification Between Former Indentured Child Laborers and Nontraumatized Controls.

Traumatic experiences may affect an individual's ability to exercise self-control, which is an essential characteristic for successfully managing life. As a measure of self-control, we used the delay discounting paradigm, that is, the extent to which a person devalues delayed gratification. The aim of this study was to investigate the relationship between childhood trauma and delay discounting using a control group design with elderly participants with a mean age of 76.2 years. Swiss former indentured child laborers (n=103) who had been exposed to trauma during their childhood were compared with nontraumatized controls (n=50). The trauma exposure group showed a considerably higher preference for immediate smaller rewards than the controls, indicating their lower self-control. A hierarchical regression analysis revealed that a history of abuse, current self-efficacy, and education were significantly associated with delay discounting. Implications for future research are discussed.

The challenge of developing a fleet driving risk assessment tool: What can be learned from the process?

One of the riskiest activities in the course of a person's work is driving. By developing and testing a new work driving risk assessment measurement tool for use by organisations this research will contribute to the safety of those who drive for work purposes. The research results highlighted limitations associated with current self-report measures and provided evidence that the work driving environment is extremely complex and involves constant interactions between humans, vehicles, the road environment, and the organisational context.

12 V / kilo-Farad Range Lead-Carbon Hybrid Ultracapacitors and Their Envisaged Applications

12 V / kilo-Farad (kF) range substrate-integrated lead-carbon hybrid ultracapacitors (HUCs) wherein the conventional positive plates of lead-acid batteries are replaced with substrate-integrated PbO2 positive plates and the negative plates are replaced with carbon-coated graphitic electrodes, providing totally non-faradaic and corrosion-free electrodes, are developed and performance tested. Constant-current discharge data at varying load-currents, constant-power discharge data at varying power values, and the capacitance data at different temperature for a 12 V / kF range substrate-integrated lead-carbon HUC are described along with its resistance, leakage current, self-discharge and cycle-life characteristics.