591 research outputs found

    d0 Perovskite-Semiconductor Electronic Structure

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    We address the low-energy effective Hamiltonian of electron doped d0 perovskite semiconductors in cubic and tetragonal phases using the k*p method. The Hamiltonian depends on the spin-orbit interaction strength, on the temperature-dependent tetragonal distortion, and on a set of effective-mass parameters whose number is determined by the symmetry of the crystal. We explain how these parameters can be extracted from angle resolved photo-emission, Raman spectroscopy, and magneto-transport measurements and estimate their values in SrTiO3

    Experimental Induction of Odontoblast Differentiation and Stimulation During Preparative Processes

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    In vivo implantation experiments have shown that ethylenediaminetetraaceticacid(EDTA)-soluble frac tions of dentin stimulate reparative dentinogenesis . When isolated embryonic dental papillae were cultured in the presence of these dentin constituents, odontoblast cytological and functional differentiation could be initiated and maintained in the absence of an enamel organ. These effects were attributed to the presence of TGF-/1- related molecules [TGF-/11 or bone morphogenetic protein -2a (BMP-2a)] which had to be used in combination with an EDT A-soluble fraction of dentin in order to specifically affect competent preodontoblasts . These EDT A-soluble constituents present in dentin could be replaced by heparin or fibronectin which both have been reported to interact with TGF-/1. The association of such defined matrix components with a TGF-/1-related molecule represents a biologically active complex triggering odontoblast functional differentiation. In response to caries, odontoblasts modulate their secretory activity and are stimulated to elaborate reactionary dentin. This might be induced by active molecules such as IGF, TGF-6 or BMP which are liberated from dentin consecutively to the demineralization process. Reparative dentinogenesis is distinct from reactionary dentinogenesis and more complex since it implicates the differentiation of precursor cells present in the dental papilla. The developmental history of these cells is different from that of the physiological predontoblasts in developing teeth. The nature of these stem cells and the mechanism of their induction still remain open questions

    More than a cognitive experience: unfamiliarity, invalidation, and emotion in organizational learning

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    Literature on organizational learning (OL) lacks an integrative framework that captures the emotions involved as OL proceeds. Drawing on personal construct theory, we suggest that organizations learn where their members reconstrue meaning around questions of strategic significance for the organization. In this 5-year study of an electronics company, we explore the way in which emotions change as members perceive progress or a lack of progress around strategic themes. Our framework also takes into account whether OL involves experiences that are familiar or unfamiliar and the implications for emotions. We detected similar patterns of emotion arising over time for three different themes in our data, thereby adding to OL perspectives that are predominantly cognitive in orientation

    Dating of the oldest continental sediments from the Himalayan foreland basin

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    A detailed knowledge of Himalayan development is important for our wider understanding of several global processes, ranging from models of plateau uplift to changes in oceanic chemistry and climate(1-4). Continental sediments 55 Myr old found in a foreland basin in Pakistan(5) are, by more than 20 Myr, the oldest deposits thought to have been eroded from the Himalayan metamorphic mountain belt. This constraint on when erosion began has influenced models of the timing and diachrony of the India-Eurasia collision(6-8), timing and mechanisms of exhumation(9,10) and uplift(11), as well as our general understanding of foreland basin dynamics(12). But the depositional age of these basin sediments was based on biostratigraphy from four intercalated marl units(5). Here we present dates of 257 detrital grains of white mica from this succession, using the Ar-40-(39) Ar method, and find that the largest concentration of ages are at 36-40 Myr. These dates are incompatible with the biostratigraphy unless the mineral ages have been reset, a possibility that we reject on the basis of a number of lines of evidence. A more detailed mapping of this formation suggests that the marl units are structurally intercalated with the continental sediments and accordingly that biostratigraphy cannot be used to date the clastic succession. The oldest continental foreland basin sediments containing metamorphic detritus eroded from the Himalaya orogeny therefore seem to be at least 15-20 Myr younger than previously believed, and models based on the older age must be re-evaluated

    Managing lifestyle change to reduce coronary risk: a synthesis of qualitative research on peoples’ experiences

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    Background Coronary heart disease is an incurable condition. The only approach known to slow its progression is healthy lifestyle change and concordance with cardio-protective medicines. Few people fully succeed in these daily activities so potential health improvements are not fully realised. Little is known about peoples’ experiences of managing lifestyle change. The aim of this study was to synthesise qualitative research to explain how participants make lifestyle change after a cardiac event and explore this within the wider illness experience. Methods A qualitative synthesis was conducted drawing upon the principles of meta-ethnography. Qualitative studies were identified through a systematic search of 7 databases using explicit criteria. Key concepts were identified and translated across studies. Findings were discussed and diagrammed during a series of audiotaped meetings. Results The final synthesis is grounded in findings from 27 studies, with over 500 participants (56% male) across 8 countries. All participants experienced a change in their self-identity from what was ‘familiar’ to ‘unfamiliar’. The transition process involved ‘finding new limits and a life worth living’ , ‘finding support for self’ and ‘finding a new normal’. Analyses of these concepts led to the generation of a third order construct, namely an ongoing process of ‘reassessing past, present and future lives’ as participants considered their changed identity. Participants experienced a strong urge to get back to ‘normal’. Support from family and friends could enable or constrain life change and lifestyle changes. Lifestyle change was but one small part of a wider ‘life’ change that occurred. Conclusions The final synthesis presents an interpretation, not evident in the primary studies, of a person-centred model to explain how lifestyle change is situated within ‘wider’ life changes. The magnitude of individual responses to a changed health status varied. Participants experienced distress as their notion of self identity shifted and emotions that reflected the various stages of the grief process were evident in participants’ accounts. The process of self-managing lifestyle took place through experiential learning; the level of engagement with lifestyle change reflected an individual’s unique view of the balance needed to manage ‘realistic change’ whilst leading to a life that was perceived as ‘worth living’. Findings highlight the importance of providing person centred care that aligns with both psychological and physical dimensions of recovery which are inextricably linked

    Psychological process from hospitalization to death among uninformed terminal liver cancer patients in Japan

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    BACKGROUND: Although the attitude among doctors toward disclosing a cancer diagnosis is becoming more positive, informing patients of their disease has not yet become a common practice in Japan. We examined the psychological process, from hospitalization until death, among uninformed terminal cancer patients in Japan, and developed a psychological model. METHODS: Terminal cancer patients hospitalized during the recruiting period voluntarily participated in in-depth interviews. The data were analyzed by grounded theory. RESULTS: Of the 87 uninformed participants at the time of hospitalization, 67% (N = 59) died without being informed of their diagnosis. All were male, 51–66 years of age, and all experienced five psychological stages: anxiety and puzzlement, suspicion and denial, certainty, preparation, and acceptance. At the end of each stage, obvious and severe feelings were observed, which were called "gates." During the final acceptance stage, patients spent a peaceful time with family, even talking about their dreams with family members. CONCLUSION: Unlike in other studies, the uninformed patients in this study accepted death peacefully, with no exceptional cases. Despite several limitations, this study showed that almost 70% of the uninformed terminal cancer patients at hospitalization died without being informed, suggesting an urgent need for culturally specific and effective terminal care services for cancer patients in Japan

    Patient Preferences in the Medical Product Life Cycle: What do Stakeholders Think? Semi-Structured Qualitative Interviews in Europe and the USA.

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    Background Patient preferences (PP), which are investigated in PP studies using qualitative or quantitative methods, are a growing area of interest to the following stakeholders involved in the medical product lifecycle: academics, health technology assessment bodies,

    When the going gets tough: Employee reactions to large‐scale organizational change and the role of employee Machiavellianism

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    Large-scale, long-term change initiatives take time to unfold, which can be a source ofuncertainty and strain. Investigating the initial 19 months of a large-scale change, weargue that during these stages, employees' change-related beliefs become more negativeover time, which negatively affects their work engagement and, ultimately, increasestheir turnover intentions. Furthermore, we investigate the impact of a trait, Machiavel-lianism, on change reactions and propose that employees high in Machiavellianism reactmore negatively during change processes as they are especially susceptible to uncer-tainty and stress. We test our (cross-level) moderated mediation model in a three-wavelongitudinal study among employees undergoing a large-scale change (T1: n = 1,602; T2:n =1,113;T3:n = 759). We find that employees' beliefs about the impact and value ofthe change are indeed negatively related to change duration and that decreases in theseperceptions come with a decline in engagement and increases in turnover intentions.Moreover, employees high in Machiavellianism react more strongly to a deterioration inchange-related beliefs, showing stronger reductions in engagement and strongerincreases in turnover intentions than employees low in Machiavellianism. Our studyoffers explanations for the negative effects of large-scale changes including an explana-tory factor for disparate employee reactions to change over time
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