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Financial risk tolerance refers to the amount of risk a person is willing to take when making financial decisions. Previous researchers have found that demographic factors when used as independent variables to have an effect on the risk tolerance behavior of investors. Within this study, emphasis was given to gender and age within a sample of South African investors. Not much research on risk tolerance and demographics has been done in South Africa. Hence, an opportunity for further research within this field emerged. This study aimed to contribute towards the accurate risk profiling of South African investors based on their level of risk tolerance considering their gender and age. This study can be used as a future forecasting tool for investment companies to predict risk tolerance levels based on gender and age levels. Results from this study correspond to previous studies where male investors are more risk tolerant than female investors. A statistical difference was also found between male and female investors within the age categories of 35-49 years and investors older than 50 years. All age categories were found to be more risk tolerant for investors older than 50 years based on the binary regression.

The experimental evidence on the voltage-dependence of the voltage acceleration factors on ultrathin oxides from 5nm down to ~ 1 nm over a wide range of voltages from ~2V to 6V is described. The area scaling method and long-term stress method is used for the investigation of the phenomenon.

Weibull slopes as a function of thickness, voltage and temperature are determined. The validity of the stress-induced leakage current measurement as an experimental means to measure the critical defect density is discussed.

Complementary resistive switching (CRS) arises when two bipolar-mode memristive devices are antiserially connected, forming a single functional structure. The combined effect of both memristors leads to the appearance of high (HRS) and low (LRS) resistance windows in the current–voltage (${I}$ – $V$) characteristic that finds application in fields such as neuromorphic computing and logic circuits. In this work, the electric behavior of HfO2-based CRS devices intentionally fabricated with a common central electrode is investigated both from experimental and modeling viewpoints. Experiments reveal that the maximum voltage applied to the structure allows tuning the amplitude of the resistance window following a self-balance dynamics. The origin of the abrupt (digital) and gradual (analog) transitions between the HRS and LRS states is elucidated through the inclusion of the snapback and snapforward effects in the switching dynamics. The ${I}$ – ${V}$ characteristics of the CRS devices are compact modeled with two opposite-biased memdiodes and simulated in LTSpice using an equivalent three-terminal subcircuit. It is shown that the proposed model is able to reproduce with a high degree of accuracy not only the observed CRS behavior for HfO2 but also the main features exhibited by devices with a wide variety of oxide/electrode materials. [ABSTRACT FROM AUTHOR]

An analysis of the trapped charge distributions of thin silicon oxide films subjected to static and dynamic stresses was presented. Voltages with different values and polarities were constantly applied to the thin films. Results revealed that trap generation rates of DC stresses were independent to stress polarity and the breakdown time for negative stress voltages was much shorter. Thus, the a smaller density of traps was needed to stimulate a final breakdown current runaway of thin silicon oxide films.

Background: In radiotherapy treatments, it is crucial to monitor the performance of linac components including gantry, collimation system, and electronic portal imaging device (EPID) during arc deliveries. In this study, a simple EPID-based measurement method is suggested in conjunction with an algorithm to investigate the stability of these systems at various gantry angles with the aim of evaluating machine-related errors in treatments. Methods: The EPID sag, gantry sag, changes in source-to-detector distance (SDD), EPID and collimator skewness, EPID tilt, and the sag in leaf bank assembly due to linac rotation were separately investigated by acquisition of 37 EPID images of a simple phantom with five ball bearings at various gantry angles. A fast and robust software package was developed for automated analysis of image data. Three Siemens linacs were investigated. Results: The average EPID sag was within 1 mm for all tested linacs. Two machines showed >1 mm gantry sag. Changes in the SDD values were within 7.5 mm. EPID skewness and tilt values were <1° in all machines. The maximum sag in leaf bank assembly was <1 mm. Conclusion: The method and software developed in this study provide a simple tool for effective investigation of the behavior of Siemens linac components with gantry rotation. Such a comprehensive study has been performed for the first time on Siemens machines. [ABSTRACT FROM AUTHOR]

Background: In radiotherapy treatments, it is crucial to monitor the performance of linac components including gantry, collimation system, and electronic portal imaging device (EPID) during arc deliveries. In this study, a simple EPID-based measurement method is suggested in conjunction with an algorithm to investigate the stability of these systems at various gantry angles with the aim of evaluating machine-related errors in treatments., Methods: The EPID sag, gantry sag, changes in source-to-detector distance (SDD), EPID and collimator skewness, EPID tilt, and the sag in leaf bank assembly due to linac rotation were separately investigated by acquisition of 37 EPID images of a simple phantom with five ball bearings at various gantry angles. A fast and robust software package was developed for automated analysis of image data. Three Siemens linacs were investigated., Results: The average EPID sag was within 1 mm for all tested linacs. Two machines showed >1 mm gantry sag. Changes in the SDD values were within 7.5 mm. EPID skewness and tilt values were <1° in all machines. The maximum sag in leaf bank assembly was <1 mm., Conclusion: The method and software developed in this study provide a simple tool for effective investigation of the behavior of Siemens linac components with gantry rotation. Such a comprehensive study has been performed for the first time on Siemens machines.