Search

This work evaluates the hydrodynamic performance of an oscillating water column wave energy converter, with a focus on comparing conventional two-way energy capture to one-way energy capture where only the up- or down-stroke is used drive the turbine. Small-scale model test experiments are performed, and numerical calculations are made using weakly-nonlinear potential flow theory. The air turbine is represented experimentally by an orifice plate with a flow area equal to about 1% of the internal-chamber water-plane area. One-way energy capture by the experimental model is realized by incorporating a passive, low-inertia, non-return valve which vents the air inside the chamber on one half-cycle of the internal water-column oscillation. In the numerical calculations, there is little difference between the two venting configurations, due to the simplified weakly non-linear model. However, the experimental results show that up-stroke venting generally yields a higher power absorption than down-stroke venting and the two-way energy capture generally yields a higher power absorption compared to the one-way energy capture. The calculations agree well with the experiments for two-way absorption, but substantially over-predict the absorbed power in the one-way configuration. This is mainly attributed to the imperfect venting system in the physical model, but further tests and/or CFD calculations are needed to confirm this conclusion.

Competing Interests: GR reports travel support from the National Indian Health Board (NIHB) to attend meetings on the Indigenous determinants of health, an NIHB conference, and the World Health Assembly. NR and GR were volunteer coauthors of the UN study(13) that is discussed in this Comment. All other authors declare no competing interests.

Background: Despite a high prevalence of substance use among women sex workers (SWs), rigorous social epidemiologic data on substance use treatment experiences among SWs remains limited. Given these gaps and the disproportionate burden of criminalization borne by Indigenous SWs, we evaluated (1) structural correlates of unsuccessful attempts to access substance use treatment; and (2) the interaction between policing and Indigenous ancestry on unsuccessful attempts to access treatment among SWs who use drugs., Methods: Prospective data were from an open community-based cohort of women SWs (2010-2019) in Vancouver, Canada. Bivariate and multivariable logistic regression with generalized estimating equations(GEE) assessed correlates of unsuccessful attempts to access treatment. A multivariable GEE confounder model examined the interaction between Indigenous ancestry and policing on unsuccessful attempts to access treatment., Results: Amongst 645 SWs who used drugs, 32.1 % reported unsuccessful attempts to access substance use treatment during the 9.5-year study. In multivariable GEE analysis, unsuccessful substance use treatment access was associated with identifying as a sexual/gender minority (AOR: 1.90, 95 %CI:1.37-2.63), opioid use (AOR: 1.43, 95 %CI: 1.07-1.91), and exposure to homelessness (AOR: 1.72; 95 %CI:1.33-2.21), police harassment (AOR: 1.48, 95 %CI:1.03-2.13), workplace violence (AOR: 1.80, 95 %CI: 1.31-2.49) and intimate partner violence (AOR: 2.11, 95 %CI:1.50-2.97). In interaction analysis, Indigenous SWs who experienced police harassment faced the highest odds of unsuccessful attempts to access substance use treatment (AOR: 2.59, 95 %CI:1.65-4.05)., Conclusion: Findings suggest a need to scale-up culturally-safe, trauma-informed addictions, gender-based violence, and sex worker services, alongside dismantling of systemic racism across and beyond health and addictions services., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Accidental overdose is a major public health concern in North America with research primarily focused on cisgender men. Little is known about the burden of overdose among marginalised women, particularly in the context of child custody loss. This study aims to examine the prevalence of overdose and the association with child removal in a cohort of marginalised women., Methods: This study draws on a merged dataset (2010-2018) of two community-based longitudinal cohorts of over 1000 marginalised women in Canada recruited using time-location sampling. After restricting to women who had ever had a live birth, bivariate and multivariable logistic regression using generalised estimating equations (GEE) were used to examine the association between child removal and overdose. Joint effects of child removal and Indigeneity were also investigated., Results: Of the 696 women who reported ever having a live birth, 39.7% (n = 276) reported child removal at baseline. Unintended, non-fatal overdose rates were high, with 35.1% (n = 244) of women reporting ever having an overdose. Using bivariate GEE analyses, having a child apprehended and being Indigenous were positively correlated with overdose. Using multivariable GEE, child removal increased the odds of overdose by 55% (AOR: 1.55; 95% CI 1.01-2.39) after adjusting for education and Indigenous ancestry. Using multivariable joint-effects analysis, Indigenous women who had experienced child removal had over twice the odds of an unintended overdose than non-Indigenous women who had not lost custody after adjusting for education, food insecurity, and sex work (AOR: 2.09; 95% CI 1.15-3.79)., Conclusion: This analysis suggests that, after controlling for known confounders, women who have a child removed experience higher odds of overdose, and these odds are highest among Indigenous women. The high prevalence of overdose in this cohort suggests the need for further strategies to prevent overdose among pregnant and parenting women., Competing Interests: Declarations of Interest The authors declare no conflict of interest., (Copyright © 2020. Published by Elsevier B.V.)

People who use drugs (PWUD) frequently have complex health care needs, yet face multiple barriers to accessing services. Involving PWUD in health service design and evaluation can enhance the quality of data collected and ensure policy and practice improvements reflect the expressed needs of the population. However, PWUD remain largely excluded from the evaluation of health services that directly affect their lives, including development of patient-reported experience measures (PREMS) that have gained prominence in health services research and clinical practice. Detailed descriptions of PWUD participation in survey design are notably absent in the literature. In this commentary, we present a case that demonstrates how PWUD can contribute meaningfully to the development of questionnaires that assess patient-reported health care experiences. We describe the development, implementation and outcomes of a process to engage local drug user organizations in the evaluation of a redesign and reorientation of health service delivery in the Downtown Eastside (DTES) neighborhood of Vancouver, Canada. Through this process, participants contributed critical elements to the design of a patient-reported experience measure, including: (1) identifying unmet service needs in the neighborhood; (2) identifying local barriers and facilitators to care; (3) formulating questions on cultural safety; and (4) improving structure, language and clarity of the questionnaire. We highlight lessons learned from the process, reflecting on the strengths, challenges and ethical considerations associated with community-based approaches to questionnaire development. The workshop model presented here illustrates one flexible and promising approach to enabling meaningful participation of PWUD in questionnaire development., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Locating areas of seafloor contamination caused by heavy oil spills is challenging, in large part because of observational limitations in aquatic subsurface environments. Accepted methods for surveying and locating sunken oil are generally slow, labor intensive and spatially imprecise. This paper describes a method to locate seafloor contamination caused by heavy oil fractions using in situ mass spectrometry and concurrent acoustic navigation. We present results of laboratory sensitivity tests and proof-of-concept evaluations conducted at the US Coast Guard OHMSETT national oil spill response test facility. Preliminary results from a robotic seafloor contamination survey conducted in deep water using the mass spectrometer and a geo-referenced acoustic navigation system are also described. Results indicate that this technological approach can accurately localize seafloor oil contamination in real-time at spatial resolutions better than a decimeter.

The NARC 1 gene encodes a novel proteinase K family proteinase. The domain structure of rat Narc 1 resembles that of the subtilisin-like proprotein convertases (SPCs), except that rNarc 1 lacks the canonical P-domain of SPCs, retaining only the RGD motif as part of what might be a cryptically functioning P-domain. Narc 1 undergoes autocatalytic intramolecular processing at the site LVFAQ/, resulting in the cleavage of its prosegment and the generation of an active proteinase with a broad alkaline pH optimum and no apparent calcium requirement for activity. Both primary and secondary structural determinants influence Narc 1 substrate recognition. Our functional characterization of Narc 1 reinforces the inference drawn from the analysis of its predicted structure that this enzyme is most closely related to representatives of the proteinase K family, but that it is also sufficiently different to warrant its possible classification in a separate sub-family.