Annual patterns of mountain runoff and its long-term trends in Japan based on dam inflow data

ObjectiveThe COVID-19 pandemic led to an increase in mortality in most countries in 2020, deviating from prior decreasing trends. In Japan, however, mortality was suggested to decrease in 2020. This...

Droughts have become more severe and frequent due to global warming. In this context, it is widely accepted that for drought assessments, both water supply (rainfall) and demand (standardized precipitation evapotranspiration index, SPEI) should be considered. Using SPEI, we explored the spatial-temporal patterns of dry and wet annual and seasonal changes in five sub-regions of East Asia during 1902–2018. These factors are linked to excess drought frequency and severity on the regional scale, and their effect on vegetation remains an important topic for climate change studies. Our results show that the SPEI significantly improved extreme drought and mostly affected the SPEI-06 and SPEI-12 growing seasons in East Asia during 1981–2018. The dry and wet annual SPEI trends mostly affect the five sub-regions of East Asia. The annual SPEI had two extremely dry spells during 1936–1947 and 1978–2018. Japan, South Korea, and North Korea are wet in the summer compared to other regions of East Asia, with drought frequency occurring at 51.4%, respectively. The mean drought frequencies in China and Mongolia are 57.4% and 54.6%. China and Mongolia are the driest regions in East Asia due to high drought frequency and duration. The spatial seasonal analysis of solar radiation (SR), water vapor pressure (WVP), wind speed (WS), vegetation condition index (VCI), temperature condition index (TCI), and vegetation health index (VHI) have confirmed that the East Asia region suffered from maximum drought events. The seasonal variation of SPEI shows no clear drying trends during summer and autumn seasons. During the winter and spring seasons, there was a dry trend in East Asia region. During 1902–1990, a seasonal SPEI presented diverse characteristics, with clear wet trends in Japan, Mongolia, and North Korea in four different growing seasons, with dry trends in China and South Korea. During 1991–2018, seasonal SPEI presented clear dry trends in Japan, Mongolia, and North Korea in different growing seasons, while China and South Korea showed a wet trend during the spring, autumn, and winter seasons. This ecological and climatic mechanism provides a good basis for the assessment of vegetation and drought-change variations within East Asia. An understandings of long-term vegetation trends and the effects of rainfall and SPEI on droughts of varying severity is essential for water resource management and climate change adaptation. Based on the results, water resources will increase under global warming, which may alleviate the water scarcity issue in the East Asia region.

Temperature differences among days of the week and their long-term trends were evaluated using 29 years of hourly data from the Automated Meteorological Data Acquisition System network of Japan. Stations were categorized with respect to the population density around each site, and an urban temperature anomaly (δT*) was defined as a departure from the spatial average of nearby rural stations. On Saturdays and holidays (Sundays and national holidays), δT* was lower than on weekdays by 0.2–0.25°C at Tokyo, by 0.1–0.2°C at Osaka, and by about 0.02°C at stations where the population density was 300 to 1,000 km–2. Moreover, δT* showed a relative decreasing trend over the long term on Mondays and an increasing trend on Fridays, at a rate of about 0.05–0.1°C decade–1 at Tokyo and about 0.02°C decade–1 at stations where the population density was 100 to 1,000 km–2, but no significant difference in δT* trends was observed between weekdays and weekend days.

Vegetables, cereals and meat are foods of interest in the aetiology of colon cancer. While vegetable consumption is considered to be protective against colon cancer, the role of cereals in colon carcinogenesis remains controversial. Colon cancer mortality has rapidly increased in Japan since the 1950s. We examined the trend of consumption of vegetables, cereals and meat in Japan during the period from 1950 to 1995. Vegetable consumption has been almost constant during the period, whereas cereal consumption has declined drastically. Meat consumption increased up until the 1970s, but the increase has been minimal thereafter. These consumption patterns suggest that cereals are an important dietary factor determining the risk of colon cancer in Japan.

Are Japanese Households Financially Healthy, and If so, Why? A Group of Seven (G7) Comparison

In this article, I conduct an international comparison of the financial health of households using data on household wealth and indebtedness for the G-7 countries and show that, even though household borrowings in Japan were the highest among the G-7 countries, at least until 2000, household assets were also high in Japan, as a result of which household net worth and financial health in Japan were among the highest in the G-7 countries. Turning to long-term trends in Japan over time, I find that Japan has shown a sharp increase over time in household borrowings, at least until 2000, and a sharp increase over time in both household assets and household net worth, at least until 1990. It is not clear whether the greater financial health of Japanese households is due more to culture or to government policies, institutions, and other noncultural factors, but it appears that long-term trends over time in household assets, liabilities, and net worth in Japan can be explained much better by noncultural factors than by culture.

The incidence of hepatocellular carcinoma (HCC) in Japan has been increasing. The aim of the present study was to analyze epidemiological changes in Japanese HCC patients. A total of 463 patients with HCC diagnosed at our hospital between 1982 and 2001 were recruited for this study. Cohorts of patients with HCC were categorized into intervals of five years. The number of HBV- and HCV-associated HCC cases had decreased and increased in 1987-1991, respectively, and thereafter reached a plateau. The mean age of patients at diagnosis of HCV-associated HCC showed a steady significant increase from 60 to 68 years of age during the period, suggesting that these findings were associated with a shift toward an older-age group that had the highest rate of HCV infection. The mean age of patients with other types of HCC did not significantly change during the period. Since it is known that the prevalence of HCV infection in young Japanese persons is low and that the incidence of HCV infection is very low at present, our findings may indicate that the prevalence of HCC will decline in Japan, an advanced country with regard to HCV-associated HCC, in the near future.

Long-term trends in Japan's manufacturing sector

The coronavirus disease (COVID-19) pandemic disrupted community-based preventive services for older adults. However, population-level evidence linking municipal implementation of such services during the pandemic to subsequent care-need outcomes remains limited. Japan's long-term care insurance (LTCI) system, in which municipalities administer preventive programs and care-need certification is conducted through a standardized process, provides an appropriate setting for examining this association. This study examined whether municipal implementation status of preventive programs planned for FY2020 was associated with subsequent trends in LTCI certification rates. We conducted a nationwide ecological analysis linking a municipal survey conducted in 2021 to annual LTCI certification rates for FY2018-2023. The exposure was full versus incomplete implementation of programs planned for FY2020 across five prevention domains: physical activity, social participation, cognitive training, nutrition, and health check-ups. Collapsed difference-in-differences models compared changes in certification rates from the pre-pandemic period (FY2018-2019) to the pandemic (FY2020-2021) and post-pandemic (FY2022-2023) periods. Event-study models estimated year-specific differences in certification-rate changes. Models were adjusted for baseline LTCI certification rate, aging rate, log-transformed population size, and fiscal capacity index. Sensitivity analyses assessed additional contextual adjustment, exclusion of municipalities without planned programs, alternative LTCI certification outcomes, and potential nonresponse bias. Of 1,741 municipalities invited, 1,114 were included in the primary analysis. Full implementation was reported by 174 municipalities (15.6%) for physical activity and 158 (14.2%) for cognitive training. Full implementation of physical activity programs was associated with smaller increases in LTCI certification rates during the pandemic period compared with incomplete implementation (-0.12% points [pp], 95% confidence intervals [CI]: -0.23 to -0.01). A comparable association was observed for cognitive training (-0.14 pp, 95%CI: -0.25 to -0.03). Sensitivity analyses generally showed similar directional patterns, although estimates were modest and less precise when additional contextual adjustment was applied, municipalities without planned programs were excluded, or alternative certification thresholds were used. In this nationwide ecological analysis, full implementation of physical activity and cognitive training programs planned for FY2020 was associated with smaller subsequent increases in municipal LTCI certification rates. These findings suggest that municipal implementation status during the COVID-19 pandemic may be related to population-level care-need trends. However, causal interpretation is limited by the ecological design, single-time assessment of implementation status, potential exposure misclassification, and possible pandemic-related changes in LTCI certification procedures.

We constructed historical (1900–) high-resolution (0.05° × 0.05°) daily precipitation data over the Japanese land area as part of the product of the “Asian Precipitation – Highly-Resolved Observational Data Integration Towards Evaluation of the Water Resources” (APHRODITE) project. This product APHRO_JP is derived from rain gauge observations and is intended to accurately represent both mean and extreme values. Due to new interpolation techniques developed in APHRODITE, estimation accuracy for orographic precipitation is improved, and bias for long-term amount is reduced, even for the early 20th century in which the observation network was sparse in space. Moreover, the product can be used for statistical analysis of heavy precipitation up to about 150 mm/day, over a long term period (≥ 100 years). APHRO_JP enables diverse research, including validation of meso-scale models and analysis of the longterm extreme precipitation trend in Japan.

Medium- and long-term population trends in Japan's rural regions and factors underlying changes are surveyed. In the 20th century, because Japan was at a stage in its demographic transition with high birth and low death rates, both non-metropolitan and metropolitan areas experienced large population growths. In rural regions, social decreases continued due to migration to metropolitan areas; however, in the 20th century, natural increase compensated for the decline and population increased. The number of births continued to decline because the birth rate remained below the population replacement level, and the number of deaths inevitably increased as a large cohort entered old age. Therefore, populations of rural regions experienced natural decreases, which are expanding. As a result, most population declines in rural regions can be explained by a natural decrease. On the other hand, social decreases also contribute to population declines in rural areas. A comparison of cohort changes reveals that the rate of females remaining at place of origin is declining in some regions. In addition, social increase rates of municipalities are positively correlated with population size. From this, it can be said that the migration of urban residents to rural settlements, as reported in the media, has been limited.

This analysis characterizes century-scale trends in exergy efficiency in Japan. Exergy efficiency captures the degree to which energy inputs (such as coal) are converted into useful work (such as electricity or power to move a vehicle). This approach enables the estimation of net efficiencies which aggregate different technologies. Sectors specifically analyzed are electricity generation, transport, steel production, and residential space heating. One result is that the aggregate exergy efficiency of the Japanese economy declined slightly over the last half of the 20th century, reaching a high of around 38% in the late 1970s and falling to around 33% by 1998. The explanation for this is that while individual technologies improved dramatically over the century, less exergy-efficient ones were progressively adopted, yielding a net stabilization or decline. In the electricity sector, for instance, adoption of hydropower was followed by fossil-fired plants and then by nuclear power, each technology being successively less efficient from an exergy perspective. The underlying dynamic of this trend is analogous to declining ore grades in the mining sector. Increasing demand for exergy services requires expended utilization of resources from which it is more difficult to extract utility (e.g., falling water versus coal). We term this phenomenon efficiency dilution.

The decline in BMI among Japanese women after World War II

The article is dedicated to studying both the long-term and current trends in Japan’s semiconductor industry. Semiconductor production is crucial for the present-day economy, and its importance is only increased by the ongoing process of digital transformation, by COVID-19 pandemic and the international political turbulence that puts strain on the existing global value chains. Moreover, semiconductors are urgently needed by electronics and car producers and by other industries that employ microchips, they could contribute to reducing Japan’s dependence on imported energy commodities. Developing the semiconductor industry is a task stated in official documents of the Japan’s government. However, Japanese semiconductor industry has been in relative decline since the late 1980-s, and the national producers now lag behind the global leaders in terms of technology. Various measures are being implemented to revitalize the industry and reverse the decline (that was partially caused by trade tensions with the US), including state subsidies and increased cooperation with foreign companies. If Japan manages to achieve its ambitious goals, such as doubling the size of the national semiconductor market by 2030 and launching the production of the new-generation microchips, it will lay the ground for other large-scale projects including the creation of ‘Society 5.0’ and the achievement of carbon neutrality. To proceed with the tasks, it is urgent that Japan’s semiconductor industry overcomes the current engineer shortage and employs the globally competitive technology. As the global demand for semiconductors expands, the semiconductor industry could become the engine of growth in other related sectors of Japan’s economy.

Secular Trends in the Incidence, Prevalence, and Disability-Adjusted Life Years of Caries in Permanent Teeth in Six Asian Countries: 1990 to 2021