580 research outputs found

    Dielectric relaxation phenomena of alkyl acrylate on complexation with phenol dissolved in carbon tetrachloride under static and high frequency electric field

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    Double relaxation times 2 and 1 due to whole molecular rotation and the flexible parts of the binary (jk) polar mixture of alkyl acrylate (j) and phenols CCl4 (i) at 35ᵒC are estimated using susceptibility data under 9.37 GHz electric field. Five systems out of twelve exhibit 2, 1 and µ2, µ1. 2’s of all systems show gradual increase with the chain length of esters offering hindrance to the rotation of the molecule. The relative contributions c1 and c2 due to 1 and 2 for five systems in terms of and curve at are estimated along with symmetric s, characteristics cs establishing the symmetric distribution of relaxation behavior. The estimated µ's and 2's agreed with the reported and measured values. The solute-solute and solute-solvent molecular associations through H-bonding are also as certained

    Service brand rehab: Diagnosing trust repair mechanisms

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    This paper aims to understand consumers’ response to the trust repair mechanisms adopted by corporate brands in a service sector context following prominent trust damaging organizational transgressions. Adopting a qualitative approach, six focus group discussions are employed to investigate three high profile consumer trust erosion cases within the service sector. Consumer trust varies by context. Despite the severity of trust damage, corporate brands can recover trust towards their brands amongst consumers not directly affected by transgressions. Not all trust repair mechanisms are equally applicable to all service contexts and re-branding could be used as a trust repair mechanism. Corporate brands in the service sector should focus on sense-making, relational approaches and transparency. Orchestration of trust repair mechanisms needs to be integrated within the trust rehabilitation processes. This study illustrates it is important to reconsider trust repair processes to accommodate context and integrate post-transgression consumer research. Successful corporate brand rehabilitation of consumer trust requires examination of the trustworthiness dimensions consumers express before and after the transgression to select the most appropriate trust repair mechanisms. Findings suggest organizations also have preventative trust repair management programs. This research is the first to empirically apply the conceptual framework of Bachmann et al. (2015) to explore consumer responses to the trust repair mechanisms adopted by corporate brands by context

    Movement Guidelines for Young Children: Engaging Stakeholders to Design Dissemination Strategies in the Hong Kong Early Childhood Education Context

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    Background Early childhood is a critical period during which patterns of movement behaviors are formed. The World Health Organization had endorsed guidelines for physical activity, sedentary behavior and sleep over a 24-h time period, which had been adopted by the Center for Health Protection of Hong Kong. This paper reports on stakeholder engagements that were conducted to inform the design of strategies to disseminate the guidelines in early childhood education (ECE) settings. Methods Using a mixed-methods study design, we sought to (a) assess the stakeholders\u27 levels of awareness and knowledge of the Hong Kong movement guidelines for young children and (b) identify the factors that influence the uptake of the said guidelines. We conducted an online survey of early childhood education teachers (N =314), twelve focus groups involving teachers (N = 18) and parents (N = 18), and individual interviews of key informants (N = 7) and domestic workers who provide care for preschool-aged children (N = 7). Descriptive statistics were used for the quantitative data, and thematic analysis was performed on the qualitative data using an inductive and semantic approach following a realist framework. Findings Our findings show that teachers were aware of the movement guidelines for young children, but their knowledge of the specific guidelines was deficient; parents and domestic workers had limited awareness and knowledge of the guidelines. Uptake of the movement guidelines is enabled by parent engagement, activities in the ECE centers, home-school cooperation, and community activities for children. The challenges include the time poverty of parents, local curriculum requirements, limited physical spaces, social values, and pandemic-related restrictions. Conclusion We recommend that dissemination strategies in the ECE context should deliver knowledge content and support stakeholders in mitigating the challenges associated with time, space, and social conditions

    Evaluation of a School-Based Dissemination of the Movement Guidelines for Young Children in Hong Kong: Study Protocol

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    Background Healthy movement behaviors in early childhood are believed to track to adulthood, potentially imparting protective benefits against non-communicable diseases. Highlighting the collaborative and complementary roles of parents and educators in promoting health of young children, this study aims to enable parents and teachers to successfully promote healthy movement behaviors in young children. Guidelines for physical activity, sedentary screen time, and sleep of children aged 2 to 6 years will be systematically disseminated to parents and teachers of children enrolled in early childhood education centers (ECECs) in Hong Kong. An evaluation will be conducted to assess the implementation process and the outcomes of the dissemination of said guidelines. Methods The evaluation will include formative and summative components to examine the implementation (i.e., process evaluation) and the outcomes (i.e., outcome evaluation). Participants include teachers, parents, and children from ECECs in Hong Kong. The process evaluation will be guided by the RE-AIM framework (i.e., reach, efficacy, adaptation, implementation, maintenance). Data gathering and analysis will take a mixed-methods triangulation design - convergence model. The outcome evaluation consists of a non-randomized observational study, using quantitative data from questionnaires and accelerometers. The primary outcome to be measured is the extent to which children meet the guidelines for physical activity, sedentary screen time, and sleep; the secondary outcome is teachers’ and parents’ knowledge and awareness of the guidelines. Discussion Young children who engage in healthy movement behaviors are likely to become adults who will have the disposition to engage in behaviors that have protective effects against non-communicable diseases. The findings of this evaluation are expected to contribute to improving the strategies of systems and government agencies that aspire to promote healthy movement behaviors of young children

    Effects of metallic spacer in layered superconducting Sr2(Mgy_yTi1y_{1-y})O3FeAs

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    The highly two-dimensional superconducting system Sr2(Mgy_yTi1y_{1-y})O3FeAs, recently synthesized in the range of 0.2 < y < 0.5, shows an Mg concentration-dependent TcT_c. Reducing the Mg concentration from y=0.5 leads to a sudden increase in TcT_c, with a maximum TcT_c ~40 K at y=0.2. Using first principles calculations, the unsynthesized stoichiometric y=0 and the substoichiometric y=0.5 compounds have been investigated. For the 50% Mg-doped phase (y=0.5), Sr2(Mgy_yTi1y_{1-y})O3 layers are completely insulating spacers between FeAs layers, leading to the fermiology such as that found for other Fe pnictides. At y=0, representing a phase with metallic Sr2TiO3 layers, the Γ\Gamma-centered Fe-derived Fermi surfaces (FSs) considerably shrink or disappear. Instead, three Γ\Gamma-centered Ti FSs appear, and in particular two of them have similar size, like in MgB2. Interestingly, FSs have very low Fermi velocity in large fractions: the lowest being 0.6×106\times10^6 cm/s. Furthermore, our fixed spin moment calculations suggest the possibility of magnetic ordering, with magnetic Ti and nearly nonmagnetic Fe ions. These results indicate a crucial role of Sr2(Mgy_yTi1y_{1-y})O3 layers in this superconductivity.Comment: 7 pages; Proceedings of ICSM-201

    Persistence of Covalent Bonding in Liquid Silicon Probed by Inelastic X-ray Scattering

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    Metallic liquid silicon at 1787K is investigated using x-ray Compton scattering. An excellent agreement is found between the measurements and the corresponding Car-Parrinello molecular dynamics simulations. Our results show persistence of covalent bonding in liquid silicon and provide support for the occurrence of theoretically predicted liquid-liquid phase transition in supercooled liquid states. The population of covalent bond pairs in liquid silicon is estimated to be 17% via a maximally-localized Wannier function analysis. Compton scattering is shown to be a sensitive probe of bonding effects in the liquid state.Comment: 5pages, 3 postscript figure

    Polymer Light‐Emitting Transistors With Charge‐Carrier Mobilities Exceeding 1 cm2 V−1 s−1

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    The vast majority of conjugated polymer-based light emitting field-effect transistors (LEFETs) are characterized by low charge carrier mobilities typically in the range 10-5 to 10-3 cm2 V-1 s-1 range. Fast carrier transport is a highly desirable characteristic for high frequency LEFET operation and, potentially, for use in electrically-pumped lasers. Unfortunately, high mobility organic semiconductors are often characterised by strong intermolecular π-π interactions that reduce luminescence. Development of new materials and/or device concepts that overcome this hurdle are therefore required. We report single organic semiconductor layer, light-emitting transistors that combine the highest hole mobilities reported to date for any polymer-based LEFET, with encouraging light emission characteristics. We achieve this in a single polymer layer LEFET, which was further enhanced through the use of a small-molecule/conjugated polymer blend system that possesses a film microstructure which supports enhanced charge carrier mobility (3.2 cm2 V-1 s-1) and promising light emission characteristics (1600 cd m-2) as compared to polymer-only based LEFETs. This simple approach represents an attractive strategy to further advance the performance of solution-processed LEFETs

    Evaluation of the Sustaining Effects of Tai Chi Qigong in the Sixth Month in Promoting Psychosocial Health in COPD Patients: A Single-Blind, Randomized Controlled Trial

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    Objectives. To evaluate the sustaining effects of Tai Chi Qigong (TCQ) in improving the psychosocial health in chronic obstructive pulmonary disease (COPD) patients in the sixth month. Background. COPD affects both physical and emotional aspects of life. Measures to minimize patients' suffering need to be implemented. Methods. 206 COPD patients were randomly assigned into three groups: TCQ group, exercise group, and control group. The TCQ group completed a three-month TCQ program, the exercise group practiced breathing and walking exercise, and the control group received usual care. Results. Significant group-by-time interactions in quality of life (QOL) using St. George's respiratory questionnaire (P = 0.002) and the perceived social support from friends using multidimensional scale of perceived social support (P = 0.04) were noted. Improvements were observed in the TCQ group only. Conclusions. TCQ has sustaining effects in improving psychosocial health; it is also a useful and appropriate exercise for COPD patients
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