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

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

Impact of Teeth on Social Participation: Modified Treatment Policy Approach

Social participation prevents social isolation and loneliness among older adults while having numerous positive effects on their health and well-being in rapidly aging societies. We aimed to estimate the effect of retaining more natural teeth on social participation among older adults in Japan. The analysis used longitudinal data from 24,872 participants in the Japan Gerontological Evaluation Study (2010, 2013, and 2016). We employed a longitudinal modified treatment policy approach to determine the effect of several hypothetical scenarios (preventive scenarios and tooth loss scenarios) on frequent social participation (1 = at least once a week/0 = less than once a week) after a 6-y follow-up. The corresponding statistical parameters were estimated using targeted minimum loss-based estimation (TMLE) method. Number of teeth category (edentate/1–9/10–19/≥20) was treated as a time-varying exposure, and the outcome estimates were adjusted for time-varying (income, self-rated health, marital status, instrumental activities of daily living, vision loss, hearing loss, major comorbidities, and number of household members) and time-invariant covariates (age, sex, education, baseline social participation). Less frequent social participation was associated with older age, male sex, lower income, low educational attainment, and poor self-rated health at the baseline. Social participation improved when tooth loss prevention scenarios were emulated. The best preventive scenario (i.e., maintaining ≥20 teeth among each participant) improved social participation by 8% (risk ratio [RR] = 1.08; 95% confidence interval [CI], 1.05–1.11). Emulated tooth loss scenarios gradually decreased social participation. A hypothetical scenario in which all the participants were edentate throughout the follow-up period resulted in a 11% (RR = 0.89; 95% CI, 0.84–0.94) reduction in social participation. Subsequent tooth loss scenarios showed 8% (RR = 0.92; 95% CI, 0.88–0.95), 6% (RR = 0.94; 95% CI, 0.91–0.97), and 4% (RR = 0.96; 95% CI, 0.93–0.98) reductions, respectively. Thus, among Japanese older adults, retaining a higher number of teeth positively affects their social participation, whereas being edentate or having a relatively lower number of teeth negatively affects their social participation

Income or education, which has a stronger association with dental implant use in elderly people in Japan?

OBJECTIVES Although inequalities in dental implant use based on educational level have been reported, no study has used income as a proxy for the socioeconomic status. We examined: (i) income inequalities in implant use; and (ii) whether income or education has a stronger association with implant use in elder Japanese. METHODS In 2016, a self‐reported questionnaire was mailed to participants aged 65 years or older living across Japan as part of the ongoing Japan Gerontological Evaluation Study. We used data from 84,718 respondents having 19 or fewer teeth. After multiple imputation, multi‐level logistic regression estimated the association of dental implant use with equivalised income level and years of formal education. Confounders were age, sex, and density of dental clinics in the residential area. RESULTS 3.1% of respondents had dental implants. Percentages of dental implant use among the lowest (≤ 9 years) and highest (≥ 13 years) educational groups were 1.8 and 5.1, respectively, and among the lowest (0 < 12.2 ‘1,000 USD/year’) and highest (≥ 59.4 ‘1,000 USD/year’) income groups were 1.7 and 10.4, respectively. A fully adjusted model revealed that both income and education were independently associated with dental implant use. Odds ratios for implant use in the highest education and income groups were 2.13 [95% CI = 1.94–2.35] and 4.85 [95% CI = 3.78–6.22] compared with the lowest education and income groups, respectively. From a model with standardised variables, income showed slightly stronger association than education. CONCLUSION This study reveals a public health problem that even those with the highest education but low income might have limited accessibility to dental implant services

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

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

Importance of socioeconomic factors in predicting tooth loss among older adults in Japan: Evidence from a machine learning analysis

Prevalence of tooth loss has increased due to population aging. Tooth loss negatively affects the overall physical and social well-being of older adults. Understanding the role of socio-demographic and other predictors associated with tooth loss that are measured in non-clinical settings can be useful in community-level prevention. We used high-dimensional epidemiological data to investigate important factors in predicting tooth loss among older adults over a 6-year period of follow-up. Data was from participants of 2010 and 2016 waves of the Japan Gerontological Evaluation Study (JAGES). A total of 19,407 community-dwelling functionally independent older adults aged 65 and older were included in the analysis. Tooth loss was measured as moving from a higher number of teeth category at the baseline to a lower number of teeth category at the follow-up. Out of 119 potential predictors, age, sex, number of teeth, denture use, chewing difficulty, household income, employment, education, smoking, fruit and vegetable consumption, community participation, time since last health check-up, having a hobby, and feeling worthless were selected using Boruta algorithm. Within the 6-year follow-up, 3013 individuals (15.5%) reported incidence of tooth loss. People who experienced tooth loss were older (72.9 ± 5.2 vs 71.8 ± 4.7), and predominantly men (18.3% vs 13.1%). Extreme gradient boosting (XGBoost) machine learning prediction model had a mean accuracy of 90.5% (±0.9%). A visual analysis of machine learning predictions revealed that the prediction of tooth loss was mainly driven by demographic (older age), baseline oral health (having 10–19 teeth, wearing dentures), and socioeconomic (lower household income, manual occupations) variables. Predictors related to wide a range of determinants contribute towards tooth loss among older adults. In addition to oral health related and demographic factors, socioeconomic factors were important in predicting future tooth loss. Understanding the behaviour of these predictors can thus be useful in developing prevention strategies for tooth loss among older adults

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

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 $m_{3/2} \sim 100$ 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 $M_I \sim 5 \times 10^{11}$ GeV for the reheating temperature $T_R = 10^6$ GeV.Comment: 9 pages, 2 figures; the version to appear in JCA

Optical Absorption Spectra of Bipolarons

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.

Inelastic Cross Sections for Proton - Nucleus Collisions at 205-GeV/c in Nuclear Emulsion

A stack of the nuclear emulsion was exposed to the 205 GeV/c proton beam at NAL. By along-the-track scanning of 1060 m, 2963 inelastic proton-nucleus collisions are obtained. The cross section for the inelastic interaction, its mass number dependence and the cross section for the coherent production are studied

Polaron effects in electron channels on a helium film

Using the Feynman path-integral formalism we study the polaron effects in quantum wires above a liquid helium film. The electron interacts with two-dimensional (2D) surface phonons, i.e. ripplons, and is confined in one dimension (1D) by an harmonic potential. The obtained results are valid for arbitrary temperature ($T$), electron-phonon coupling strength ($\alpha$), and lateral confinement ($\omega_{0}$). Analytical and numerical results are obtained for limiting cases of $T$, $\alpha$, and $\omega_{0}$. We found the surprising result that reducing the electron motion from 2D to quasi-1D makes the self-trapping transition more continuous.Comment: 6 pages, 7 figures, submitted to Phys. Rev.

Construction of 3⊗33\otimes 3 entangled edge states with positive partial transposes

We construct a class of $3\otimes 3$ entangled edge states with positive partial transposes using indecomposable positive linear maps. This class contains several new types of entangled edge states with respect to the range dimensions of themselves and their partial transposes.Comment: 14 page