885 research outputs found

    Resilience, well-being and informal and formal support in multi-problem families during the Covid-19 pandemic

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    BACKGROUND: The Covid-19 pandemic may have had negative effects on youth and parental mental health, especially in high-risk populations such as multi-problem families (i.e., families that experience problems in multiple domains, such as mental health and social network problems). Using one to four assessments during all phases of the Covid-19 pandemic up until January 2022, we examined the associations between pandemic-related stress and mental health (resilience and well-being) of youth and parents from multi-problem families. We also investigated whether experienced informal (i.e., youth informal mentoring) and formal support (i.e., therapist support) served as protective factors in this association. METHODS: A total of 92 youth aged 10–19 years (46.7% girls; mean age 16.00 years) and 78 parents (79.5% female; mean age 47.17 years) filled in one to four questionnaires between March 2020 and January 2022. Multi-level analyses were conducted to account for the nested structure of the data. RESULTS: For youth, pandemic-related stress was associated with lower well-being, but not with resilience. Perceived support from both mentors and therapists was positively associated with youth mental health. Furthermore, high perceived therapist support protected youth from the negative effect of pandemic-related stress on resilience. For parents, pandemic-related stress was not related to mental health, irrespective of therapist support. Yet, therapist support was directly and positively associated with parental mental health. CONCLUSIONS: Youth from multi-problem families who experience pandemic-related stress are at risk of (elevated) mental health problems during the pandemic, specifically if they have no or weak therapist support. The mental health of parents, however, was minimally affected by pandemic-related stress, indicating strength and flexibility. Youth and parents who experienced support during the pandemic reported higher levels of resilience and well-being, demonstrating the importance of support for individuals’ mental health during stressful times such as a pandemic. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13034-022-00542-2

    Morphological Stability of Copper Surfaces under Reducing Conditions

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    Though copper is a capable electrocatalyst for the CO2 reduction reaction (CO2RR), it rapidly deactivates to produce mostly hydrogen. A current hypothesis as to why this occurs is that potential-induced morphological restructuring takes place, leading to a redistribution of the facets at the interface resulting in a shift in the catalytic activity to favor the hydrogen evolution reaction over CO2RR. Here, we investigate the veracity of this hypothesis by studying the changes in the voltammetry of various copper surfaces, specifically the three principal orientations and a polycrystalline surface, after being subjected to strongly cathodic conditions. The basal planes were chosen as model catalysts, while polycrystalline copper was included as a means of investigating the overall behavior of defect-rich facets with many low coordination steps and kink sites. We found that all surfaces exhibited (perhaps surprisingly) high stability when subjected to strongly cathodic potentials in a concentrated alkaline electrolyte (10 M NaOH). Proof for morphological stability under CO2RR-representative conditions (60 min at -0.75 V in 0.5 M KHCO3) was obtained from identical location scanning electron microscopy, where the mesoscopic morphology for a nanoparticle-covered copper surface was found unchanged to within the instrument accuracy. Observed changes in voltammetry under such conditions, we found, were not indicative of a redistribution of surface sites but of electrode fouling. Besides impurities, we show that (brief) exposure to oxygen or oxidizing conditions (i.e., 1 min) leads to copper exhibiting changing morphology upon cathodic treatment which, we posit, is ultimately the reason why many groups report the evolution of copper morphology during CO2RR: accidental oxidation/reduction cycles.Catalysis and Surface Chemistr

    Electrocatalysis under cover: enhanced hydrogen evolution via defective graphene-covered Pt(111)

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    The production of hydrogen via water electrolysis using renewable electricity is a promising carbon-neutral technology. In this contribution, we report insights into the hydrogen evolution reaction (HER) in H2SO4 on Pt(111) and graphene-covered Pt(111), in addition to the electrochemical properties of graphene overlayers. As-prepared graphene overlayers are selectively permeable to H+ ions in the electrolyte, allowing H+ ions into the confined layer between graphene and Pt(111) while excluding SO42- and other anions. We demonstrate that defects in these as-prepared graphene overlayers can be generated from oxidation at high overpotentials or reduction from the production of H-2 bubbles and postulate that HER occurs locally at only Pt(111) in the proximity of defects in graphene overlayers on asprepared G/Pt(111) electrodes, and as defects in graphene increases, more of the Pt(111) surface becomes utilized for HER. Kinetically, the addition of defective graphene overlayers can increase the geometric HER rate by up to 200%, while Tafel slopes and [H+] reaction orders remain unchanged. These results shed kinetic insight into the nature of graphene overlayers and their effect on HER catalysis and also demonstrate the promise of confinement modifications in designing catalysts with properties closer to achieving optimum rates.Catalysis and Surface Chemistr

    Nonequilibrium Dynamics and Aging in the Three--Dimensional Ising Spin Glass Model

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    The low temperature dynamics of the three dimensional Ising spin glass in zero field with a discrete bond distribution is investigated via MC simulations. The thermoremanent magnetization is found to decay algebraically and the temperature dependent exponents agree very well with the experimentally determined values. The nonequilibrium autocorrelation function C(t,tw)C(t,t_w) shows a crossover at the waiting (or {\em aging}) time twt_w from algebraic {\em quasi-equilibrium} decay for times tt≪\lltwt_w to another, faster algebraic decay for tt≫\ggtwt_w with an exponent similar to one for the remanent magnetization.Comment: Revtex, 11 pages + 4 figures (included as Latex-files

    Aging Relation for Ising Spin Glasses

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    We derive a rigorous dynamical relation on aging phenomena -- the aging relation -- for Ising spin glasses using the method of gauge transformation. The waiting-time dependence of the auto-correlation function in the zero-field-cooling process is equivalent with that in the field-quenching process. There is no aging on the Nishimori line; this reveals arguments for dynamical properties of the Griffiths phase and the mixed phase. The present method can be applied to other gauge-symmetric models such as the XY gauge glass.Comment: 9 pages, RevTeX, 2 postscript figure

    New directions for lifelong learning using network technologies

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    Please refer only to original source: Koper, R., Tattersall, C. (2004). New directions for lifelong learning using network technologies. British Journal of Educational Technology, 35 (6), 689-700.The requirements placed on learning technologies to support lifelong learning differ considerably from those placed on technologies to support particular fragments of a learning lifetime. The time scales involved in lifelong learning, together with its multi-institutional and episodic nature are not reflected in today’s mainstream learning technologies and their associated architectures. The article presents an integrated model and architecture to serve as the basis for the realization of networked learning technologies serving the specific needs and characteristics of lifelong learners. The integrative model is called a “Learning Network” (LN) and its requirements and architecture are explored, together with the ways in which its application can help in reducing barriers to lifelong learning

    Outlining the scaling-based and scaling-free optimization of electrocatalysts

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    Catalysis and Surface Chemistr

    Fluctuation Dissipation Ratio in Three-Dimensional Spin Glasses

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    We present an analysis of the data on aging in the three-dimensional Edwards Anderson spin glass model with nearest neighbor interactions, which is well suited for the comparison with a recently developed dynamical mean field theory. We measure the parameter x(q)x(q) describing the violation of the relation among correlation and response function implied by the fluctuation dissipation theorem.Comment: LaTeX 10 pages + 4 figures (appended as uuencoded compressed tar-file), THP81-9

    Clean and reproducible voltammetry of copper single crystals with prominent facet-specific features using induction annealing

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    Although copper is widely used as an electrocatalyst for the CO2 reduction reaction, often little emphasis is placed on identifying exactly the facet distribution of the copper surface. Furthermore, because of differing surface preparation methodologies, reported characaterization voltammograms (where applicable) often vary significantly between laboratories, even for surfaces of supposedly the same orientation. In this work, we describe a surface preparation methodology involving the combination of induction annealing and well-documented electrochemical steps, by which reproducible voltammetry for copper surfaces of different orientations can be obtained. Specifically, we investigated copper surfaces of the three principal orientations: {111}, {100} and {110}, and a representative polycrystalline surface. We compared these surfaces to surfaces reported in the literature prepared via either electropolishing or UHV-standard methodologies, where we find induction preparation to yield improvements in surface quality with respect to electropolished surfaces, though not quite as good as those obtained by UHV-preparation.Catalysis and Surface Chemistr
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