Global COVID-19 Pandemic Waves: Limited Lessons Learned Worldwide over the Past Year

The occurrence of coronavirus disease 2019(COVID-19)was followed by a small burst of cases around the world;afterward,due to a series of emergency non-pharmaceutical interventions(NPIs),the increas-ing number of confirmed cases slowed down in many countries.However,the lifting of control measures by the government and the public’s loosening of precautionary behaviors led to a sudden increase in cases,arousing deep concern across the globe.arousing deep concern across the globe.This study evaluates the situation of the COVID-19 pandemic in countries and territories worldwide from January 2020 to February 2021.According to the time-varying reproduction number(R(t))of each country or territory,the results show that almost half of the countries and territories in the world have never controlled the epidemic.Among the countries and territories that had once contained the occurrence,nearly half failed to maintain their prevention and control,causing the COVID-19 pandemic to rebound across the world—resulting in even higher waves in half of the rebounding countries or territories.This work also proposes and uses a time-varying country-level transmission risk score(CTRS),which takes into account both R(t)and daily new cases,to demonstrate country-level or territory-level transmission potential and trends.Time-varying hierarchical clustering of time-varying CTRS values was used to successfully reveal the countries and territories that contributed to the recent aggravation of the global pandemic in the last quarter of 2020 and the beginning of 2021,and to identify countries and territories with an increasing risk of COVID-19 transmission in the near future.Furthermore,a regression analysis indicated that the introduction and relaxation of NPIs,including workplace closure policies and stay-at-home requirements,appear to be associated with recent global transmission changes.In conclu-sion,a systematic evaluation of the global COVID-19 pandemic over the past year indicates that the world is now in an unexpected situation,with limited lessons learned.Summarizing the lessons learned could help in designing effective public responses for constraining future waves of COVID-19 worldwide.

Investigating the relationships between facets of work task and selection and query-related behavior

Purpose: This study aims to explore the relationships between different facets of work task and selection and query-related behavior.Design/methodology/approach:An experiment was conducted to explore the issue. The researcher recruited 24 participants and assigned six simulated work task situations to each of them. Each experiment lasted around 2 hours and was recorded by the software tool Morae.Findings: Time(frequency) and time(length) are more closely related to user’s selection and query-related behavior compared to the facet ‘process’ of work task. Knowledge level of work task topic, degree of work task difficulty, and subjective work task complexity are significantly correlated with selection and query-related behavior. Work task difficulty and work task complexity are different concepts. Subjective work task complexity, work task difficulty, and knowledge of work task topic are significantly correlated with user’s selection and query-related behavior.Research limitations/implications: The limitations of this study include a small sample size,limited work task situations, and possible spurious relationships. This study has implications in informing task-based information seeking/search/retrieval research and interactive information retrieval(IIR) systems design.Originality/values: Previous studies usually did not touch upon how different facets of work tasks affected interactive activities. Some studies examining task complexity and information behavior were concerned with how work tasks affect users’ behavior at information-seeking level, rather than at information search level. This study makes contribution to interactive information retrieval,task-based information search and retrieval, and personalization of IR.

Chinese college students' understanding of Internet ethical issues: A survey of awareness

Purpose: This study examines Chinese college students’ awareness of ethical issues surrounding the use of information resources and the Internet and their attitude to these issues. Design/methodology/approach: A survey was conducted. Two hundred questionnaires were distributed to students of 9 universities at different levels in Tianjin, China; 171 were returned. Descriptive statistics were performed to analyze the data. Findings: The results indicate that Chinese college students usually ignored the negative influence of fake or pornographic or other indecent information, invasion of privacy and theft of confidential information, and violation of intellectual property rights. Although they could distinguish to some extent between ethical and unethical behavior, they were not concerned about others’ unethical behavior on the Web. The study also indicates that gender, age, academic major and expertise in using computers were related to the students’ awareness of ethical issues relating to the use of the Internet and their attitude to these issues.Research limitations: The sample is limited to the universities in Tianjin. A larger sample, which includes colleges and universities in the western or other developing areas in China, is needed to further validate our findings.Practical implications: The study helps educators and academic librarians better understand Chinese college students’ awareness of and attitude to ethical issues surrounding the use of the Internet. It thus could assist them in the improvement of information ethics education for college students.Originality/value: This study was one of the first empirical studies to investigate the factors influencing Chinese college students’ awareness of and attitude to Internet ethical issues.

C:N:P stoichiometry of Ericaceae species in shrubland biomes across Southern China:influences of climate,soil and species identity

Aims Carbon(C),nitrogen(N)and phosphorus(P)stoichiometry strongly affect functions and nutrient cycling within ecosystems.However,the related researches in shrubs were very limited.In this study,we aimed to inves-tigate leaf stoichiometry and its driving factors in shrubs,and whether stoichiometry significantly differs among closely related species.Methods We analyzed leaf C,N and P concentrations and their ratios in 32 species of Ericaceae from 161 sites across southern China.We examined the relationships of leaf stoichiometry with environmen-tal variables using linear regressions,and quantified the interactive and independent effects of climate,soil and species on foliar stoi-chiometry using general linear models(GLM).Important Findings The foliar C,N and P contents of Ericaceae were 484.66,14.44 and 1.06 mg g−1,respectively.Leaf C,N and P concentrations and their ratios in Ericaceae were significantly related with latitude and altitude,except the N:P insignificantly correlated with latitude.Climate(mean annual temperature and precipitation)and soil properties(soil C,N and P and bulk density)were significantly influenced element stoichiom-etry.The GLM analysis showed that soil exerted a greater direct effect on leaf stoichiometry than climate did,and climate affected leaf traits mainly via indirect ways.Further,soil properties had stronger influ-ences on leaf P than on leaf C and N.Among all independent factors examined,we found species accounted for the largest proportion of the variation in foliar stoichiometry.These results suggest that species can largely influence foliar stoichiometry,even at a lower taxonomic level.

季节性干旱驱动亚热带森林的碳积累

本研究旨在表明处于南亚热带的鼎湖山生物圈保护区的干旱频率和强度正在增加,并说明季节性干旱对亚热带森林碳积累的影响。这是为了应对全球气候变化导致的干旱加剧所带来的威胁开展的一项研究。我们使干旱指数(标准化降水指数、标准降水蒸散发指数、降水距平百分率及自校准帕尔默干旱指数)准确确定干旱期和降水量增加期。此后,将2003至2014年(12年)监测采集的实测涡动通量和土壤含水量数据在干旱期和湿润期之间进行比较,以确定干旱对生态系统碳积累的影响。在本研究所选择的12年期间,干旱的发生时间约占比20%,最强干旱事件和严重程度发生于2012至2013年。研究期间的年平均降水量和气温分别为1404.57±43.2 mm和22.65±0.1°C,与30年记录(1990–2020)相比较,年降水量减少量可达523 mm,而气温则增加了2.55°C。与全球针对大多数森林生态系统研究所发表的数据呈相反趋势,处于中国南亚热带区域的鼎湖山生物圈保护区在60%的干旱期内所监测的森林生态系统记录到显著的碳积累趋势,说明季节性干旱驱动了森林的碳积累。

One-step supramolecular preorganization constructed crinkly graphitic carbon nitride nanosheets with enhanced photocatalytic activity

Here we report a new one-step thermal polycondensation process to form crinkly graphitic carbon nitride nanosheets(CGCNNs)via supramolecular preorganization,using a mixture of urea and melamine as the starting material.Systematical studies reveal that the newly developed CGCNNs significantly strengthen the optical absorption,widen the bandgap,and increase the Hall mobility and carrier density compared to that of its bulk counterpart,regardless of the similar chemical composition and structure.As a result,the photocatalytic hydrogen production rate is improved by 7 times.Moreover,Na doping of CGCNNs can further promote its photocatalytic activity,leading to an excellent photocatalytic hydrogen production rate of 250.9μmol h^(–1),which is approximately 10.5 times higher than its bulk counterpart.Moreover,an impressive apparent quantum efficiency of 19.12%is achieved at 420 nm.This study provides a facile strategy for the design of efficient low-cost carbon-nitride-based photocatalysts for solar fuel production.

Water-use efficiency of four native trees under CO_(2) enrichment and N addition in subtropical model forest ecosystems

Aims We aimed to evaluate the changes in water-use efficiency(WuE)in native tree species in forests of subtropical China,and determine how coexisting species would be responding to increases in atmospheric carbon dioxide(CO_(2))concentrations and nitrogen(N)deposition.Methods We used model forest ecosystems in open-top chambers to study the effects of elevated CO_(2)(ca.700μmol mol−1)alone and together with N addition(NH4No3 applied at 100 kg N ha−1year−1)on WuE of four native tree species(Schima superba,Ormosia pin-nata,Castanopsis hystrix and Acmena acuminatissima)from 2006 to 2010.Important findingsour result indicated that all species increased their WuE when they were exposed to elevated CO_(2).although higher WuE was shown in faster-growing species(S.superba and O.pinnata)than that of slower-growing species(C.hystrix and Acmena acuminatissima),the increased extent of WuE induced by elevated CO_(2) was higher in the slower-growing species than that of the faster-growing species(P<0.01).the N treatment decreased WuE of S.superba,while the effects on other species were not significant.the interactions between elevated CO_(2) and N addition increased intrinsic WuE of S.superba significantly(P<0.001),however,it did not affect WuE of the other tree species significantly.We conclude that the responses of native tree species to elevated CO_(2) and N addition are different in subtropical China.the species-specific effects of elevated CO_(2) and N addition on WuE would have important implications on species composition in China’s subtropics in response to global change.

Environmental remediation promotes the restoration of biodiversity in the Shenzhen Bay Estuary,South China

Background:Rapid urbanization has greatly changed land-use patterns in many estuarine areas around the world,including the Guangdong-Hong Kong-Macao Greater Bay Area(GBA)resulting in serious water pollution and ecosystem degradation.Shenzhen City has conducted comprehensive ecological management and restoration in the Shenzhen Bay since 2007.The natural vegetation consisting of mangroves,semi-mangroves,wetland plants,and terrestrial plants were restored from the bund to the inner bank of the Fengtang River.Rain and sewage flow diversion systems were established.The non-point source and point-source sewage are now treated in municipal sewage treatment plants,then naturally flow through the constructed wetland,and then through a natural wetland,restored natural embankment,and finally through mangrove communities substantially improving water quality.Result:The restoration of the wetland has increased animal and microbial diversity and has supported the establishment of a complex and stable food web.With water purification and habitat restoration,the number of alien invasive plants in the estuarine ecosystem has decreased,and the diversity of native species of birds,fish,macrobenthos,amphibians,and reptiles has increased.Conclusion:These improvements indicate that human beings and nature can coexist in support of the sustainable development of Shenzhen City.