Racially-motivated housing discrimination experienced by Indigenous postsecondary students in Canada: impacts on PTSD symptomology and perceptions of university stress.

OBJECTIVES: To examine the impacts of housing discrimination experienced by Indigenous postsecondary students on post-traumatic stress disorder (PTSD) symptomology and perceptions of university stress. STUDY DESIGN: Cross-sectional study. METHODS: Data were gathered via in-person surveys completed by 142 Indigenous students between 2015 and 2017. Associations were analyzed using phi coefficients and linear regression models adjusted for confounders. Qualitative data were examined using thematic analyses. RESULTS: Indigenous students who had children (almost 50% of the sample), were living with a romantic partner, and/or were between the ages of 25-44 years experienced significantly more racially-motivated housing discrimination than other Indigenous students in the sample. The frequency of housing discrimination in the past 12 months was significantly associated with increased PTSD symptoms; particularly, intrusive recollection and more perceived stress at university in linear regression models adjusted for confounders. Every 1-point increase in the frequency of housing discrimination on a 4-point scale resulted in a 5.4-point increase in PTSD score. Although living with a romantic partner resulted in more housing discrimination, it also served as a resilience factor, buffering the impact of housing discrimination on PTSD symptomology. Qualitative data indicated students faced Racially-motivated housing discrimination that was blunt and deliberate and highlighted the resourceful ways students sought to resist it. CONCLUSIONS: Racially-motivated housing discrimination exacerbated PTSD symptomology among Indigenous students and adversely impacted perceptions of their university experience. Efforts are needed to address housing discrimination directly, as well as provide greater family-focused housing and mental wellness supports to Indigenous students to reduce potential impacts of this public health problem on postsecondary success and degree completion.

Optimizing the performance of the entropic splitter for particle separation.

Recently, it has been shown that entropy can be used to sort Brownian particles according to their size. In particular, a combination of a static and a time-dependent force applied on differently sized particles which are confined in an asymmetric periodic structure can be used to separate them efficiently, by forcing them to move in opposite directions. In this paper, we investigate the optimization of the performance of the "entropic splitter." Specifically, the splitting mechanism and how it depends on the geometry of the channel, and the frequency and strength of the periodic forcing is analyzed. Using numerical simulations, we demonstrate that a very efficient and fast separation with a practically 100% purity can be achieved by a proper optimization of the control variables. The results of this work could be useful for a more efficient separation of dispersed phases such as DNA fragments or colloids dependent on their size.

Electret accelerometers: physics and dynamic characterization.

Electret microphones are produced in numbers that significantly exceed those for all other microphone types. This is due to the fact that air-borne electret sensors are of simple and low-cost design but have very good acoustical properties. In contrast, most of the discrete structure-borne sound sensors (or accelerometers) are based on the piezoelectric effect. In the present work, capacitive accelerometers utilizing the electret principle were constructed, built, and characterized. These electret accelerometers comprise a metallic seismic mass, covered by an electret film, a ring of a soft cellular polymer supplying the restoring force, and a metallic backplate. These components replace membrane, spacer, and back electrode, respectively, of the electret microphone. An adjustable static pressure to the seismic mass is generated by two metal springs. The dynamic characterization of the accelerometers was carried out by using an electrodynamic shaker and an external charge or voltage amplifier. Sensors with various seismic masses, air gap distances, and electret voltages were investigated. Charge sensitivities from 10 to 40 pC/g, voltage sensitivities from 600 to 2000 mV/g, and resonance frequencies from 3 to 1.5 kHz were measured. A model describing both the charge and the voltage sensitivity is presented. Good agreement of experimental and calculated values is found. The experimental results show that sensitive, lightweight, and inexpensive electret accelerometers can be built.