Bayesian analysis of a Tobit quantile regression model

This paper develops a Bayesian framework for Tobit quantile regression. Our approach is organized around a likelihood function that is based on the asymmetric Laplace dis- tribution, a choice that turns out to be natural in this context. We discuss families of prior distribution on the quantile regression vector that lead to proper posterior distributions with ¯nite moments. We show how the posterior distribution can be sampled and summarized by Markov chain Monte Carlo methods. A method for com- paring alternative quantile regression models is also developed and illustrated. The techniques are illustrated with both simulated and real data. In particular, in an em- pirical comparison, our approach out-performed two other common classical estimators

Experimental Study of Electrophoretic Deposited Carbon Nanotubes on Microstrip Transmission Line Resonators and Filters

The electrical properties of single-walled carbon nanotube electrophoreses deposition on different types of gold-plated microstrip devices are investigated. Simple transmission lines, transmission line resonators and filters were subjected to deposition of functionalized tubes in an aqueous solution. It is found that the process lowers the resonant frequency of the resonators and filters compared to the untreated devices, at the cost of increased insertion loss and reduced resonator Q-factor

Evidence of Klein tunneling in graphene p-n junctions

Transport through potential barriers in graphene is investigated using a set of metallic gates capacitively coupled to graphene to modulate the potential landscape. When a gate-induced potential step is steep enough, disorder becomes less important and the resistance across the step is in quantitative agreement with predictions of Klein tunneling of Dirac fermions up to a small correction. We also perform magnetoresistance measurements at low magnetic fields and compare them to recent predictions.Comment: Major changes made: 1) Taking into account properly the contribution of the resistance of monopolar junctions to the odd part of the resistance. To better present the results we use a fitting parameter for the amplitude of screening in graphene. 2) Wrong data for the diffusive model in figures 3, 9 and 10 was plotted in former version. 3) Figure 5 moved to EPAP

Ultra-compact capacitively loaded evanescent half-mode SIW filters for LTE applications

This paper presents a novel miniaturized substrate integrated waveguide filter by combining both half-mode resonators and capacitive loading on a conventional two-layer printed circuit board (PCB) process..

Prehospital emergency care provider’s understanding of their responsibilities towards a mental health care user, during a behavioural emergency

Background: Prehospital emergency care providers in South Africa are regularly called to assist with the management of mental healthcare users. The Mental Health Care Act no 17 of 2002 regulates mental healthcare in South Africa but makes no reference to the roles and responsibilities of prehospital emergency care providers in the provision of mental healthcare, rather giving the South African Police Services authority over the wellbeing of a mental healthcare user outside the hospital setting. Aims: To investigate what prehospital emergency care providers understand their responsibilities are towards a mental healthcare user and the community during the management of a behavioural emergency. Setting: Prehospital emergency care providers from the three main levels of care, currently operational within the boundaries of Pretoria. Methods: A grounded theory qualitative study design was chosen using semi-structured focus groups for each level of prehospital emergency care; Basic Life Support, Intermediate Life Support and Advanced Life Support. Data from each focus group was collected through audio recordings, transcribed and analysed using a framework approach. Results: A total of 19 prehospital emergency care providers from all three main levels of care participated in the focus group discussions (4 BLS, 6 ILS and 9 ALS). Four main themes were identified: Perceptions of behavioural emergencies, responsibilities, understanding of legislation and barriers experienced. Conclusion: Participants placed high value on their moral and medical responsibilities towards a mental healthcare user and would like to have the backing of legislation to fulfil their role. There is a desire for better education, skill development and awareness of mental healthcare in the prehospital emergency care setting