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Cell voltage at high current densities (HCD) of an operating proton-exchange membrane fuel cell (PEMFC) suffers from losses due to the local-O2 and bulk-H+ transport resistances in the cathode catalyst layer (CCL). Particularly, the interaction of perfluorosulfonic acid (PFSA) ionomer with the carbon supported platinum catalyst plays a critical role in controlling reactant transport to the active site. In this study, we perform a systematic analysis of the side chain length and equivalent weight (EW) of PFSA ionomers on the CCL transport resistances. Ex situ measurements were carried out to quantify the ionomer characteristics such as the molecular weight, proton conductivity and water uptake. Nanomorphology of ionomers cast as 60-120 nm thin-films is characterized using grazing-incidence X-ray scattering. In situ fuel cell electrochemical diagnostic measurements were carried out to quantify the reactant (H+/O2) transport properties of the CCL. Ionomer EW was found to play a major role with decreasing EW yielding higher proton conductivity and water uptake that led to lower bulk-H+ and local-O2 transport resistances in the CCL. Finally, a 1D-semi-empirical performance model has been developed to quantify the impact of ionomer EW on cell voltage loss factors.

Objective: Reading is often cited as beneficial for one's mental health, but the research on this topic is limited. The goal of the present research was to examine whether recreational reading is beneficial for mental health during college, and to determine what motivates recreational reading. Participants: Participants were 231 university students from a large Canadian University. Methods: A longitudinal design was employed and students completed online surveys on recreational reading, motivation, psychological distress and need frustration at the beginning and end of the academic year. Results: Recreational reading was associated with reduced psychological distress over the school year. Recreational reading seemed to buffer against the frustration of one's basic psychological needs which led to improved mental health over the school year. Students who were more autonomously motivated reported reading more books recreationally. Conclusion: Recreational reading is a simple and cost-effective tool to help college students cope with mental health problems.

The near edge x-ray absorption fine structure (NEXAFS) spectra of ethylene on Pt(111) at 90 and 300 K have been measured and compared to the spectra calculated using the multiple scattering Xα method for cluster models of adsorbed ethylene and ethylidyne. The results indicate that ethylene is adsorbed in the di-σ configuration (sp3 hybridization) at 90 K, and that the π* orbital retains its identity in this configuration, with no component along the C–C axis. The spectrum obtained at 300 K is attributed to ethylidyne (CCH3) and the calculated spectrum for a cluster consisting of this species bonded symmetrically to three Pt atoms is in good agreement with experiment. The calculations show that the multiple scattering molecular cluster approach is a useful technique for interpreting the NEXAFS spectra of adsorbed molecules. [ABSTRACT FROM AUTHOR]

Presents a study which determined free-carrier effective masses in mercury telluride-cadmium telluride superlattices using measurements of oscillatory magnetoresistance. Agreement of the study findings with the predictions of band-structure theory; Details of the Shubnikov-de Haas oscillations in both n- and p-type mercury telluride-cadmium telluride superlattices.

Optimized conditions for imaging and spectroscopic/elemental mapping of thin perfluorosulfonic acid (PFSA) ionomer layers in fuel cell electrodes by scanning transmission electron microscopy (STEM) have been investigated. The proper conditions were first identified using model systems of either Nafion ionomer-coated nanostructured thin film catalysts or thin films on nanoporous Si. These analysis conditions were then applied in a quantitative study of the ionomer through-layer loading for two differently-prepared electrode catalyst layers using electron energy loss (EELS) and energy dispersive X-ray spectroscopy (EDS) in the STEM. The electron-beam induced damage to the PFSA ionomer was quantified by following the fluorine mass loss with electron dose/exposure and was mitigated by several orders of magnitude using cryogenic specimen cooling and a higher incident electron voltage. Multivariate statistical analysis was applied to the analysis of both EELS and EDS spectrum images for data de-noising and unbiased separation of the independent components related to the catalyst, ionomer, and support distributions within the catalyst layers. [ABSTRACT FROM AUTHOR]

Recent educational research suggests that both mastery goals and performance-approach goals are beneficial for students, whereas performance-avoidance goals are harmful. The present study examined whether the same pattern of results would generalize to the domains of music and sports. High-level musicians and athletes reported their goals prior to a peak performance and a catastrophic performance. The results among athletes mirrored findings in the educational domain, with both mastery and performance-approach goals being associated with optimal functioning. The results among musicians, however, diverged in showing that performance goals were markedly more detrimental than mastery goals. It was also found that intrinsic goals associated with a focus on enjoyment were particularly helpful for musicians. Mediational analyses showed that musicians¿ greater vulnerability to performance-related anxiety accounted for the more damaging impact of performance goals. These findings suggest some possible danger in emphasizing any form of performance goal in domains such as music where performance-related anxiety is prevalent. [ABSTRACT FROM AUTHOR]

Studies the relation between parenting experiences at age five and level of self-criticism at age twelve. Stability of self-criticism from age 12 to age 31; Parental restrictiveness and rejection, and the development of self-criticism in children; Stability of self-criticism in women from adolescence to adulthood; Differences in stability of self-criticism for men; More.

Resonant tunneling has been demonstrated through a double barrier, single quantum well HgTe/Hg1-xCdxTe heterostructure for the first time. Negative differential resistance is observable at room temperature, exhibiting a 1.4:1 peak to valley tunnel current ratio. The observation provides direct evidence for the existence of the proposed intrinsic interface state. [ABSTRACT FROM AUTHOR]

We report an x-ray diffraction study of a HgTe-CdTe superlattice (SL)/HgCdTe heterostructure grown by molecular beam epitaxy (MBE). The diffraction results are used to place an upper bound on the misfit accommodation at the lattice-mismatched SL/HgCdTe interface. The misfit accommodation at the heterointerface is at least an order of magnitude less than that predicted by equilibrium misfit theory. It appears that the low substrate temperature used in MBE HgCdTe growth imposes a kinetic barrier to misfit accommodation. [ABSTRACT FROM AUTHOR]

Two-dimensional electronic properties of HgTe films (∼2 μm thick) grown by molecular beam epitaxy on CdTe substrates have been investigated by using the Shubnikov–de Haas effect. Electron densities, effective masses, and Dingle temperatures of three electric subbands in an accumulation layer near the HgTe-CdTe interface have been determined for two samples with different total densities. The results exhibit behavior typical of an asymmetric triangular potential well and a pronounced band nonparabolicity. [ABSTRACT FROM AUTHOR]

The Black population in Canada is characterized by its long-established history and diversity. The present study aims to expand our current understanding of the relation between discrimination and disparities in healthcare by including race and language as determinants of health. We recruited 531 Black adults who are currently living in Quebec, Canada, to complete a survey measuring socio-demographic characteristics, mental and physical health, accessibility to healthcare, and experiences of discrimination. Results showed that being a racialized and linguistic minority population in Quebec, English-speaking Black participants experienced more discrimination, fewer healthcare providers, less access to COVID-19 information during the COVID-19 pandemic, and were more dissatisfied with the healthcare system than French-speaking Black participants. Furthermore, the negative impacts of healthcare access associated with being a racialized and linguistic minority population in Quebec (e.g., the English-speaking Black population) were shown to be mediated by experiences of discrimination and dissatisfaction with the healthcare system., (© 2023. W. Montague Cobb-NMA Health Institute.)

Schizophrenia, a debilitating psychiatric disorder, has a long-term impact on social and occupational functioning. While negative symptoms, notably amotivation, are recognized as poor prognostic factors, the positive force of patient motivation (autonomous motivation) remains underexplored. This systematic review, guided by Self-Determination Theory (SDT), investigated the impact of motivation on clinical presentation, and treatment engagement and response in schizophrenia-spectrum disorders. Fifty-five independent studies (N = 6897), using 23 different motivation scales, met inclusion criteria. Results were categorized into cross-sectional and longitudinal correlates of autonomous motivation, and the effects of motivational interventions. Cross-sectionally, autonomous motivation was positively associated with social/occupational functioning, and negatively associated with negative and positive symptom severity. In longitudinal studies, baseline autonomous motivation predicted engagement in and response to social/occupational treatments, with mixed results in cognitive interventions. In the 16 randomized controlled trials (RCTs), the most common motivational interventions were individualized goal setting and goal attainment support, followed by increasing sense of competence by challenging defeatist beliefs, and enhancing relatedness by increasing contact time. Motivational interventions consistently increased autonomous motivation, treatment engagement and response. More studies are needed, particularly studies that monitor motivation during treatment: proximal assessments could facilitate the identification of treatment elements that impact motivation and engagement and inform treatment modifications to enhance the patient experience and improve treatment efficacy., Competing Interests: Declaration of competing interest M.L. reports grants from Roche, grants from Otsuka Lundbeck Alliance, personal fees from Otsuka Canada, personal fees from Lundbeck Canada, grants and personal fees from Janssen, and personal fees from MedAvante-Prophase, outside the submitted work. HT, ÉCA, RK, and GO'D declare that they have no known competing financial interests, employment, personal, or other competing relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Examining the spectrum of vaccine attitudes within the general public, spanning from hesitancy to confidence, is pivotal in addressing the challenges posed by the COVID-19 pandemic. Despite widespread campaigns advocating for vaccine uptake, a proportion of the population harbour reservations about the safety and efficacy of vaccines. This study seeks to explore the determinants of vaccine attitudes in Canada, leveraging key concepts from the well-established Self-Determination Theory (SDT), including basic psychological needs and the quality of an individual's motivation. During a crucial juncture in the COVID-19 pandemic (December 2021), 292 participants were recruited and completed an online survey assessing levels of satisfaction/frustration of basic psychological needs (sense of autonomy, relatedness, and competence), vaccine attitudes (confidence and hesitancy), and motivation towards vaccination (controlled and autonomous). Two mediation models were employed to examine whether autonomous-controlled motivation mediated the relationship between need satisfaction-frustration and vaccine attitudes. Model 1 revealed a full mediating effect, indicating that need satisfaction influenced vaccine confidence only through autonomous motivation (ab 1  = 0.09, SE = 0.04, z = 2.19, 95 % CI [0.01, 0.18]). Meanwhile, Model 2 demonstrated that need frustration was associated with vaccine hesitancy partially through controlled motivation (ab 2  = 0.05, SE = 0.02, z = 2.54, 95 % CI [0.02, 0.10]). These findings underscore the applicability of SDT in investigating the motivational mechanisms that shape vaccine attitudes. Recognizing psychosocial factors, including the balance of basic needs and quality of motivations, may be integral to informing effective public health strategies., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Quebec's English-speaking Black community finds itself at the intersection of racial and linguistic discrimination, which presents challenges to mental wellness. The present study aims to add necessary detail to the conversations surrounding racism and mental health in Canada while including language as a determinant of health and intersecting element affecting the wellbeing of English-speaking Black Quebecers. We recruited 531 Black adults who are currently living in Quebec to complete a survey on various community-relevant items, including their mental and physical health, their experiences of discrimination, and barriers to accessing mental healthcare. Our analyses revealed that English-speaking participants experience more discrimination across all types and report more barriers to mental healthcare and lower mental health than their French-speaking counterparts. Furthermore, we found that language also had a mediated effect on mental health through discrimination and barriers to mental healthcare. Our study adds to the sparse race-based and intersectional literature about Black people in Canada and substantiates a mechanism by which language affects mental health by exposing Black Quebecers to more discrimination and thus higher barriers to care., (© 2023. W. Montague Cobb-NMA Health Institute.)

A longitudinal study involving 455 Black young adults living in Canada investigated whether gender and autonomous motivation influenced the relationship between perceived racism threat and Black Lives Matter (BLM) activism, and whether BLM activism influenced life satisfaction over time. A moderated mediation analysis using PROCESS Macro Model 58 tested the indirect effect of autonomous motivation on the relationship between perceived racism threat and BLM activism varying by gender. Multiple linear regression assessed how well BLM activism predicted life satisfaction. Black women perceived greater racism threat than Black men related to increases in BLM activism via the influence of autonomous motivation. BLM activism had a positive influence on life satisfaction over time, regardless of gender. This research suggests Black young women are playing pivotal roles in the BLM movement and helps us understand how motivation may be influencing involvement and well-being in social justice issues., (© 2023 The Authors. Journal of Community Psychology published by Wiley Periodicals LLC.)

The present study investigates whether the way Black young adults constructed their narratives regarding the stressful events of the COVID-19 pandemic and the black lives matter (BLM) protests related to adjustment over time. A two-wave mixed prospective and retrospective longitudinal study was conducted in July and December 2020 and included a total of 90 Black young adults. Narrative reports were collected at baseline to determine the psychological interpretations of the two events and were coded based on affect disclosure. Both time points examined adjustment to the COVID-19 pandemic and the BLM protests as well as the extent to which the basic psychological needs for autonomy, relatedness, and competence were affected. Our results showed that disclosure of high arousal negative affect in narratives at baseline was associated with better adjustment over time. Additionally, results of process analyses showed that satisfaction of the basic psychological need for autonomy (e.g., feelings of personal agency, choice, and volition) mediated the association between narratives and adjustment. These results suggest that engaging in disclosure of high arousal negative affect may be associated with heightening adjustment because it enhances individuals' autonomy, perhaps resulting in a beneficial integration of the events into their broader life narratives. These findings highlight the potential of well-constructed narratives to impact adjustment over time and have implications for clinical practice to support Racialized communities during unprecedented events., (© 2022 Wiley Periodicals LLC.)