2,548 research outputs found

    Non-thermal Leptogenesis and a Prediction of Inflaton Mass in a Supersymmetric SO(10) Model

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    The gravitino problem gives a severe constraint on the thermal leptogenesis scenario. This problem leads us to consider some alternatives to it if we try to keep the gravitino mass around the weak scale m3/2100m_{3/2} \sim 100 GeV. We consider, in this paper, the non-thermal leptogenesis scenario in the framework of a minimal supersymmetric SO(10) model. Even if we start with the same minimal SO(10) model, we have different predictions for low-energy phenomenologies dependent on the types of seesaw mechanism. This is the case for leptogenesis: it is shown that the type-I see-saw model gives a consistent scenario for the non-thermal leptogenesis but not for type-II. The predicted inflaton mass needed to produce the observed baryon asymmetry of the universe is found to be MI5×1011M_I \sim 5 \times 10^{11} GeV for the reheating temperature TR=106T_R = 10^6 GeV.Comment: 9 pages, 2 figures; the version to appear in JCA

    Dental Status and Compression of Life Expectancy with Disability

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    This study examined whether the number of teeth contributes to the compression of morbidity, measured as a shortening of life expectancy with disability, an extension of healthy life expectancy, and overall life expectancy. A prospective cohort study was conducted. A self-reported baseline survey was given to 126,438 community-dwelling older people aged ≥65 y in Japan in 2010, and 85,161 (67.4%) responded. The onset of functional disability and all-cause mortality were followed up for 1,374 d (follow-up rate = 96.1%). A sex-stratified illness-death model was applied to estimate the adjusted hazard ratios (HRs) for 3 health transitions (healthy to dead, healthy to disabled, and disabled to dead). Absolute differences in life expectancy, healthy life expectancy, and life expectancy with disability according to the number of teeth were also estimated. Age, denture use, socioeconomic status, health status, and health behavior were adjusted. Compared with the edentulous participants, participants with ≥20 teeth had lower risks of transitioning from healthy to dead (adjusted HR, 0.58 [95% confidence interval (CI), 0.50-0.68] for men and 0.70 [95% CI, 0.57-0.85] for women) and from healthy to disabled (adjusted HR, 0.52 [95% CI, 0.44-0.61] for men and 0.58 [95% CI, 0.49-0.68] for women). They also transitioned from disabled to dead earlier (adjusted HR, 1.26 [95% CI, 0.99-1.60] for men and 2.42 [95% CI, 1.72-3.38] for women). Among the participants aged ≥85 y, those with ≥20 teeth had a longer life expectancy (men: +57 d; women: +15 d) and healthy life expectancy (men: +92 d; women: +70 d) and a shorter life expectancy with disability (men: -35 d; women: -55 d) compared with the edentulous participants. Similar associations were observed among the younger participants and those with 1 to 9 or 10 to 19 teeth. The presence of remaining teeth was associated with a significant compression of morbidity: older Japanese adults' life expectancy with disability was compressed by 35 to 55 d within the follow-up of 1,374 d

    Experience of childhood abuse and later number of remaining teeth in older Japanese: a life-course study from Japan Gerontological Evaluation Study project

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    OBJECTIVES: From a life-course perspective, adverse childhood experiences (ACEs) such as childhood abuse are known risk factors for adult diseases and death throughout life. ACEs could also cause poor dental health in later life because they could induce poor dental health in childhood, initiate unhealthy behaviors, and lower immune and physiological functions. However, it is not known whether ACEs have a longitudinal adverse effect on dental health in older age. This study aimed to investigate the association between experience of childhood abuse until the age of 18 and current number of remaining teeth among a sample of older Japanese adults. METHODS: A retrospective cohort study was conducted using the data from the Japan Gerontological Evaluation Study (JAGES), a large-scale, self-reported survey in 2013 including 27 525 community-dwelling Japanese aged ≥65 years (response rate=71.1%). The outcome, current number of remaining teeth was used categorically: ≥20, 10-19, 5-9, 1-4, and no teeth. Childhood abuse was defined as having any experience of physical abuse, psychological abuse, and psychological neglect up until the age of 18 years. Ordered logistic regression models were applied. RESULTS: Of the 25 189 respondents who indicated their number of remaining teeth (mean age: 73.9; male: 46.5%), 14.8% had experience of childhood abuse. Distributions of ≥20, 10-19, 5-9, 1-4, and no teeth were as follows: 46.6%, 22.0%, 11.4%, 8.2%, and 11.8% among respondents with childhood abuse, while 52.3%, 21.3%, 10.3%, 6.6%, and 9.5% among respondents without childhood abuse. Childhood abuse was significantly associated with fewer remaining teeth after adjusting for covariates including socioeconomic status (odds ratio=1.14; 95% confidence interval: 1.06, 1.22). CONCLUSIONS: Childhood abuse could have a longitudinal adverse effect on later dental health in older age. This study emphasizes the importance of early life experiences on dental health throughout later life

    Spin Transport in Two Dimensional Hopping Systems

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    A two dimensional hopping system with Rashba spin-orbit interaction is considered. Our main interest is concerned with the evolution of the spin degree of freedom of the electrons. We derive the rate equations governing the evolution of the charge density and spin polarization of this system in the Markovian limit in one-particle approximation. If only two-site hopping events are taken into account, the evolution of the charge density and of the spin polarization is found to be decoupled. A critical electric field is found, above which oscillations are superimposed on the temporal decay of the total polarization. A coupling between charge density and spin polarization occurs on the level of three-site hopping events. The coupling terms are identified as the anomalous Hall effect and the recently proposed spin Hall effect. Thus, an unpolarized charge current through a sheet of finite width leads to a transversal spin accumulation in our model system.Comment: 15 pages, 3 figure

    Social and Behavioural Determinants of the Difference in Survival among Older Adults in Japan and England

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    BACKGROUND: A rapidly ageing population presents major challenges to health and social care services. Cross-country comparative studies on survival among older adults are limited. In addition, Japan, the country with the longest life expectancy, is rarely included in these cross-country comparisons. OBJECTIVE: We examined the relative contributions of social and behavioural factors on the differences in survival among older people in Japan and England. METHODS: We used data from the Japan Gerontological Evaluation Study (JAGES; n = 13,176) and the English Longitudinal Study of Ageing (ELSA; n = 5,551) to analyse all-cause mortality up to 9.4 years from the baseline. Applying Laplace regression models, the 15th survival percentile difference was estimated. RESULTS: During the follow-up, 31.3% of women and 38.6% of men in the ELSA died, whereas 19.3% of women and 31.3% of men in the JAGES died. After adjusting for age and baseline health status, JAGES participants had longer survival than ELSA participants by 318.8 days for women and by 131.6 days for men. Family-based social relationships contributed to 105.4 days longer survival in JAGES than ELSA men. Fewer friendship-based social relationships shortened the JAGES men’s survival by 45.4 days compared to ELSA men. Currently not being a smoker contributed to longer survival for JAGES women (197.7 days) and ELSA men (46.6 days), and having lower BMI reduced the survival of JAGES participants by 129.0 days for women and by 212.2 days for men. CONCLUSION: Compared to participants in England, Japanese older people lived longer mainly because of non-smoking for women and family-based social relationships for men. In contrast, a lower rate of underweight, men’s better friendship-based social relationships, and a lower smoking rate contributed to survival among participants in England

    Free energy of the Fr\"ohlich polaron in two and three dimensions

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    We present a novel Path Integral Monte Carlo scheme to solve the Fr\"ohlich polaron model. At intermediate and strong electron-phonon coupling, the polaron self-trapping is properly taken into account at the level of an effective action obtained by a preaveraging procedure with a retarded trial action. We compute the free energy at several couplings and temperatures in three and two dimensions. Our results show that the accuracy of the Feynman variational upper bound for the free energy is always better than 5% although the thermodynamics derived from it is not correct. Our estimates of the ground state energies demonstrate that the second cumulant correction to the variational upper bound predicts the self energy to better than 1% at intermediate and strong coupling.Comment: RevTeX 7 pages 3 figures, revised versio

    Optical Absorption Spectra of Bipolarons

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    The absorption of large bipolarons is investigated using the path-integral method. The response of a bipolaron to an external electromagnetic field is derived in the framework of the memory-function approach. The bipolaron optical absorption spectrum consists of a series of relatively narrow peaks. The peculiarities of the bipolaron optical absorption as a function of the frequency of the electromagnetic field may be attributed to the transitions involving relaxed excited states and scattering states of a bipolaron.Comment: 14 pages, 3 figures, E-mail addresses: [email protected], [email protected]; to be published in Phys. Rev.

    Surface-initiated growth of copper using isonicotinic acid-functionalized aluminum oxide surfaces

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    Isonicotinate self-assembled monolayers (SAM) were prepared on alumina surfaces (A) using isonicotinic acid (iNA). These functionalized layers (iNA-A) were used for the seeded growth of copper films (Cu-iNA-A) by hydrazine hydrate-initiated electroless deposition. The films were characterized by scanning electron microscopy (SEM), electron-dispersive X-ray spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and advancing contact angle measurements. The films are Cu0 but with surface oxidation, and show a faceted morphology, which is more textured (Rq = 460 ± 90 nm) compared to the SAM (Rq = 2.8 ± 0.5 nm). In contrast, growth of copper films by SnCl2/PdCl2 catalyzed electroless deposition, using formaldehyde (CH2O) as the reducing agent, shows a nodular morphology on top of a relatively smooth surface. No copper films are observed in the absence of the isonicotinate SAM. The binding of Cu2+ to the iNA is proposed to facilitate reduction to Cu0 and create the seed for subsequent growth. The films show good adhesion to the functionalized surface
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