Coal is not only an important energy source in China but also a major source of air pollution. Because of this, China's national sulfur dioxide (SO(2)) emissions have been the highest in the world for many years, and since the 1990s, the territory of China's south and southwest has become the third largest acid-rain-prone region in the world. In order to control SO(2) emissions, the Chinese government has formulated and promulgated a series of policies and regulations, but it faces great difficulties in putting them into practice. In this retrospective look at the history of SO(2) control in China, we found that Chinese SO(2) control policies have become increasingly strict and rigid. We also found that the environmental policies and regulations are more effective when central officials consistently give environmental protection top priority. Achieving China's environmental goals, however, has been made difficult by China's economic growth. Part of this is due to the practice of environmental protection appearing in the form of an ideological "campaign" or "storm" that lacks effective economic measures. More recently, better enforcement of environmental laws and regulations has been achieved by adding environmental quality to the performance assessment metrics for leaders at all levels. To continue making advances, China needs to reinforce the economic and environmental assessments for pollution control projects and work harder to integrate economic measures into environmental protection. Nonetheless, China has a long way to go before economic growth and environmental protection are balanced.

ObjectiveTo describe Chinese older adults’ willingness to enter long-term care facilities and to examine individual factors associated with the willingness of using this growing model of long-term care in China.MethodsA cross-sectional study involving a random sample of 670 adults aged 60+ in the Hezuo community in Chengdu, China in 2016. Respondents were interviewed by trained staff on socio-demographics, health status, quality of life, social support, and willingness to enter long-term care facilities.ResultsOnly 11.9% of the respondents were willing to enter long-term care facilities for meeting their medical and social service needs. Multivariable logistic regression analysis showed that willingness to enter long-term care facilities was associated with higher household income (OR = 4.55, 95% CI:1.72–12.00), insurance of Urban Resident Basic Medical Insurance (OR = 4.80, 95% CI:1.17–19.67) and unemployment (OR = 0.48, 95% CI:0.24–0.99). Among those who were willing to enter long-term care facilities, an overwhelming majority (81.2%) would prefer going to a facility within 30-minute walking distance from their current residence, 82.5% indicated the need of nursing care, and 90.0% expected a partnership between the long-term care facility and a large hospital.ConclusionsA minority of older Chinese were willing to receive long-term care delivered at a facility within walking distance from their current residence. Recent policy aimed at increasing the supply of long-term care facilities may not be consistent with consumer preference for home and community-based care. Balancing investment between home and community-based care, and establishing long-term care insurance remain the top priorities for long-term care research and policy development in China.

IntroductionAsymptomatic infection of SARS-CoV-2 may lead to silent community transmission and compromise the COVID-19 pandemic control measures. We aimed to estimate the rate of asymptomatic COVID-19 from published studies and compare this rate among different regions and patient groups.MethodsIn this systematic review and meta-analysis, electronic databases including Medline, Embase, PubMed and three Chinese electronic databases (Chinese National Knowledge Infrastructure [CNKI], WanFang Data and China Science, and Technology Journal Database [VIP]) were searched for literature published from 1 November 2019 to 31 December 2020. Original investigations with sample size (or number of subjects) not less than five were included for further analyses. Subgroup analyses were conducted according to different study types, study periods, geographical regions and patient demographics. The STATA (V.14.0) command ‘metaprop’ was implemented to conduct a meta-analysis of the pooled rate estimates of asymptomatic infections with exact binomial and score test-based 95% confidence interval (CI).ResultsA total of 130 123 ascertained COVID-19 infections from 241 studies were included in this meta-analysis, including 31 411 asymptomatic infections. The overall rate of asymptomatic infections was 23.6% (18.5%–29.1%) and 21.7% (16.8%–27.0%) before and after excluding presymptomatic cases, respectively. Subgroup analysis showed that significantly higher in pregnant women (48.8%, 28.9%–68.9%), children (32.1%, 24.2%–40.5%), and studies reporting screening programmes (36.0%, 24.6%–48.1%) conducted on or after 1 March 2020 (42.5%, 33.4%–51.9%). In terms of geographical region, the rate was the highest in Africa (64.3%, 56.7%–71.6%), followed by America (40.0%, 27.4%–53.3%), Europe (28.1%, 19.0%–38.1%) and Asia (18.1%, 13.2%–23.5%).ConclusionWe approximated that one-fifth of COVID-19 infections are asymptomatic throughout the course of infection. Public health policies targeting these high-risk groups may be recommended to achieve early identification and more stringent containment of the pandemic.

Background Severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and coronavirus disease 2019 (COVID-19) have caused substantial public health burdens and global health threats. Understanding the superspreading potential of a virus is important for characterizing transmission patterns and informing strategic decision-making in disease control. This systematic review aimed to summarize the existing evidence on superspreading features and to compare the heterogeneity in transmission within and among various coronavirus epidemics of SARS, MERS and COVID-19. Methods PubMed, Medline, and Embase databases were extensively searched for original studies on the transmission heterogeneity of SARS, MERS, and COVID-19 published in English between January 1, 2003, and February 10, 2021. After screening the articles, we extracted data pertaining to the estimated dispersion parameter ( k ) which has been a commonly-used measurement for transmission heterogeneity and superspreading potential. Findings We included a total of 60 estimates of transmission heterogeneity from 26 studies on outbreaks in 22 regions. The majority (90%) of the k estimates were small, with values less than 1, indicating an over-dispersed transmission pattern. The point estimates of k for SARS and MERS ranged from 0.12 to 0.20 and from 0.06 to 2.94, respectively. Among 45 estimates of individual-level transmission heterogeneity for COVID-19 from 17 articles, 91% were derived from Asian regions. The point estimates of k for COVID-19 ranged between 0.1 and 5.0. Conclusions We detected a substantial over-dispersed transmission pattern in all three coronaviruses, while the k estimates varied by differences in study design and public health capacity. Our findings suggested that even with a reduced R value, the epidemic still has a high resurgence potential due to transmission heterogeneity.

As a fundamental category of river system, comparisons in diverse regions and types with quantitative parameters on meander morphology will help to distinguish different characteristics and approach formations and evolutions. It also can provide scientific basis of geomorphology for their protections and exploitation of the meander resources. Based on the images of Google Earth, meanders' parameters are proposed and then measured and calculated. The result suggests that incised meanders in the Jialing River are among the most complex, irregular and sinuous channels. Special river gradient, geological structures, strata and lithology, backwater effect of landform are key factors to shape meanders of the Jialing River. The evolution of meander in the Jialing River obeys the principle of minimum-maximum energy dissipation. Easy acquisitions of remote sensing data make regional and global comparisons possible, and then the differences of formations can be explored. The morphology can probably provide an evidence of antecedent river and demonstrate the channel incisions and crustal uplifts. Meander core in Chinese is named after the isolated hills in the Jialing River. The incised meander is a kind of resource and needs to be protected.