Nonlinear polarization evolution using time-dependent density functional theory

We propose a theoretical and computational approach to investigate temporal behavior of a nonlinear polarization in perturbative regime induced by an intense and ultrashort pulsed electric field. First-principles time-dependent density functional theory is employed to describe the electron dynamics. Temporal evolution of third-order nonlinear polarization is extracted from a few calculations of electron dynamics induced by pulsed electric fields with the same time profile but different amplitudes. We discuss characteristic features of the nonlinear polarization evolution as well as an extraction of nonlinear susceptibilities and time delays by fitting the polarization. We also carry out a decomposition of temporal and spatial changes of the electron density in power series with respect to the field amplitude. It helps to get insight into the origin of the nonlinear polarization in atomic scale.Comment: 11 pages, 9 figure

Developing a Teaching Plan for the Social Studies of a Junior High School Focused on Inquiring What is a Good Society : Based on the Learning Principles of the New Course of Studies.

本研究は,平成20年3月に改訂された中学校学習指導要領のもとでの中学校社会科の単元開発のあり方を,公民的分野の内容(4)-イ｢よりよい社会を目指して｣を取り上げて具体的に示そうとするものである｡今回の学習指導要領改訂では,中学校社会科には目標レベルの変化はほとんど見られず,一見,改訂は小幅なものにとどまったかに思われる｡しかしながら,内容を検討すると,地理,歴史,公民の三分野ともに学習原理に関わる大きな転換がなされていることが分かり,それを見逃すと改訂の本質は見えない｡本研究では,新学 習指導要領の学習原理として特に注目されている探究活動の充実に焦点をしぼり,学習原理の転換がいかになされたかということに加えて,具体的にいかなる授業づくりが求められるかを事例に基づいて明らかにした

Why Are COVID-19 Mortality Rates by Country or Region So Different?: An Ecologic Study of Factors Associated with Mortality from Novel Coronavirus Infections by Country

[Background] In order to find out the factors associated with the large disparities in COVID-19 mortality rates by country, we conducted an ecological study by linking existing statistics. In Japan, a large variation was observed in between geographical areas when assessing mortality. We performed a regional correlation analysis to find factors related to regional mortality. [Methods] This study design was an ecologic study. A multiple regression analysis was performed with COVID-19 mortality rates of different countries as the dependent variable together with various health care and economic factors. We calculated the cumulative mortality rate as of June 30, 2020. For the regional correlation analysis of Japan, 47 prefectures were divided into nine regions. The factors examined were health care and tourism. Data for 33 Organization for Economic Co-operation and Development (OECD) countries were analyzed. In Japan’s regional analysis, the whole country was classified into nine regions. [Results] Factors related to mortality were the incidence of Kawasaki disease (KD), number of computed tomographies (CTs), and alcohol consumption. Mortality was low in countries with high incidence of KD and high number of CTs, as well as in countries with high alcohol consumption. In European countries, high smoking prevalence and a high Gini coefficient were positively related to high mortality. According to a regional analysis in Japan, mortality was related to proportion of population in the densely inhabited districts, the number of foreign visitors per capita, and the number of Chinese visitors per capita. [Conclusion] Low mortality in East Asia was associated with specific disease morbidity (KD), alcohol consumption, and CT numbers. It was suggested that the mortality gap in Japan was related to the number of foreign tourists and the proportion of population in the densely inhabited districts

Developmental Changes of Prefrontal Activation in Humans: A Near-Infrared Spectroscopy Study of Preschool Children and Adults

Previous morphological studies indicated that development of the human prefrontal cortex (PFC) appears to continue into late adolescence. Although functional brain imaging studies have sought to determine the time course of functional development of the PFC, it is unclear whether the developmental change occurs after adolescence to adulthood and when it achieves a peak because of the narrow or discontinuous range in the participant's age. Moreover, previous functional studies have not focused on the anterior frontal region, that is, the frontopolar regions (BA9/10). Thus, the present study investigated the developmental change in frontopolar PFC activation associated with letter fluency task by using near-infrared spectroscopy (NIRS), in subjects from preschool children to adults. We analyzed the relative concentration of hemoglobin (ΔHb) in the prefrontal cortex measured during the activation task in 48 typically-developing children and adolescents and 22 healthy adults. Consistent with prior morphological studies, we found developmental change with age in the children/adolescents. Moreover, the average Δoxy-Hb in adult males was significantly larger than that in child/adolescent males, but was not true for females. These data suggested that functional development of the PFC continues into late adolescence. Although the developmental change of the frontopolar PFC was independent of gender from childhood to adolescence, in adulthood a gender difference was shown

Suicide rates during social crises: Changes in the suicide rate in Japan after the Great East Japan earthquake and during the COVID-19 pandemic

We aimed to observe the changes in suicide rates after the Great East Japan Earthquake and during the coronavirus (COVID-19) pandemic, as typical cases of social crises, in Japan. A descriptive epidemiological study was conducted using data on the number of deaths by suicide published by the National Police Agency. The suicide rate ratio during the crisis—the monthly suicide mortality rate in the year of the crisis divided by the average suicide mortality rate in the three years before the crisis—was used as the indicator. After the earthquake, in March 2011 the suicide rate was 18% lower than the average mortality rate for the previous three years. However, it increased by 18% in May and 8% in June; increased mortality was observed among women. The suicide rate began to decline after October 2011. During the COVID-19 pandemic, the suicide rate decreased from February to June 2020. The declines in April and May were significant at 20% and 18%, respectively. From July onwards, the suicide rate of women began to rise, and from October, the overall suicide also began to increase. The rise in female suicide rates was significant, especially in October, with an increase of 70%. Thus, during these crises, suicide rates fell temporarily but then rose, especially among women. The period of increase in suicide rates was longer during the COVID-19 pandemic than after the earthquake. Therefore, there is an urgent need to promote measures for suicide prevention currently, and during a future crisis

Age determination by skeletochronology of the Japanese giant salamander Andrias japonicus (Amphibia, Urodela)

In the past several years, a number of studies have been carried out on the behavioral and reproductive ecology of the Japanese giant salamander Andrias japonicus, but the age and longevity of A. japonicus has not yet been studied. In this study, we attempted to establish an age determination method using specimens (age: 1 to 11 years old) from Hiroshima City Asa Zoological Park that lived and died in captivity. The cross sections of phalangeal bones were nearly circular in shape, and hematoxylinophilic lines that were interpreted as lines of arrested growth (LAGs) were observed in the periosteal tissue; this suggests that this technique can be used to estimate the age of A. japonicus. The number of LAGs was one less than the number of winters that each individual experienced. We could observe LAGs in both frozen and 10% formalin specimens. LAGs could be confirmed even for specimens that had been fixed in formalin for up to 30 years. By using this method, it was suggested that the lifespan of this species could be determined from specimens existing in museums, zoos, and aquariums worldwide. It also showed potential for providing important conservation information, such as generation time and age structure of populations in the field.This work supported by JSPS KAKENHI Grant Numbers JP 26870400, JP 17K 01209

Trends in sleep problems and patterns among Japanese adolescents: 2004 to 2017

Background Sleep problems in adolescence, such as insomnia and short sleep duration, are associated with physical and mental health problems. However, little is known about the recent trends in sleep problems among adolescents. Therefore, this study examined trends in sleep problems among Japanese adolescents. Methods Using data from the Lifestyle Survey of Adolescents collected in 2004 (n = 102,451), 2008 (n = 95,680), 2010 (n = 98,867), 2012 (n = 101,134), 2014 (n = 85,931), and 2017 (n = 64,417), we calculated the trends of insomnia, shorter sleep duration, late bedtimes, and poor sleep quality. Multivariable logistic regression analysis models were used to examine the association of each sleep problem and survey years. Findings We analyzed data from 545,285 Japanese adolescents. Results indicated that, since 2004, the odds ratio for insomnia have decreased (Adjusted odds ratio [AOR] 0•85, 95% CI 0•82–0•87), as have the odds ratio for poor sleep quality (AOR 0•92, 95% CI 0•88–0•95). However, the odds ratio for shorter sleep duration (AOR 1•13, 95% CI 1•10–1•17) and late bedtimes tended to increase (AOR 1•06, 95% CI 1•03–1•08) during this period. Interpretation The prevalence of insomnia symptoms and poor sleep quality among adolescents decreased from 2004 to 2017. However, there were increasing trends toward shorter sleep duration and late bedtimes. These changes are both relieving and concerning. Teachers, parents, and health professionals should consider educating adolescents regarding sleep hygiene, adjusting schedules of extracurricular activities, and enhancing time management to improve their sleep quantity

Effectiveness of Screening and Brief Alcohol Intervention at the Workplace: A Study Protocol for a Randomized Controlled Trial at Five Japan-Based Companies

Background: Despite evidence regarding the effectiveness of screening and brief interventions for excessive alcohol use in primary care, these tools are not a part of routine practice. It has been suggested that using these tools at the workplace may be critical to alcohol-associated harm; however, evidence for this claim is unclear. The aim of this article is to develop a study protocol which evaluates the effect of brief alcohol intervention at the workplace to reduce harmful alcohol drinking. Methods: A randomized controlled trial involving employees (aged 20–74 years) of five Japan-based companies who were screened “positive” by Alcohol Use Disorder Identification Test (AUDIT) is on-going. Participants were randomized into “Patient Information Leaflet” (control group), “Brief Advice and Counselling,” and “Five-minute Brief Advice” groups. A self-administered questionnaire was used to assess alcohol consumption, lifestyle behavior, health status, work performance, and consequences of alcohol use. Data of laboratory markers were collected from routine health checkups.Results: A total of 351 participants were randomized into Patient Information Leaflet (n = 111), Brief Advice and Counselling (n = 128), and Five-minute Brief Advice (n = 112) groups. Participants were mostly men with a median age of 49 years. Median AUDIT score and weekly alcohol consumption were 11 points and 238 g/week, respectively. Two-thirds of the participants were manufacturing workers. Conclusion: This study protocol developed the first trial in Japan to investigate the effect of brief alcohol intervention combined with a recommended screening tool at the workplace. Our findings can provide evidence on the effectiveness and relevance of these tools to occupational health