In middleschool English teaching,grammar instruction has always been an important and challenging aspect.Due to the strong influence of grammar explanation in Chinese,learning English grammar may be affected by negati...In middleschool English teaching,grammar instruction has always been an important and challenging aspect.Due to the strong influence of grammar explanation in Chinese,learning English grammar may be affected by negative transfer from their native language,which could pose certain obstacles to English acquisition.Self-efficacy,as a major emotional factor influencing learners'internal regulation strategies,has attracted wide attention from researchers both domestically and internationally for its impact on learning performance.High self-efficacy helps learners develop a more positive mindset towards learning,thereby contributing to improved learning performance.Therefore,this study focuses on investigating the relationship between grammatical self-efficacy and learning performance of English grammar among middle school students.This research contributes to a complementary understanding of grammatical self-efficacy among educators,enhancing their teaching skills,and effectively guiding students to learn English grammar with a more positive and healthy mindset,presenting a future grammar instruction in middle school English teaching.展开更多
The core issue concerning the usage of tense and aspect is seen as significantly important(Michaelis,1994;Swales and Feak,2000),especially in English writing in college.This study identifies the erroneous use of tense...The core issue concerning the usage of tense and aspect is seen as significantly important(Michaelis,1994;Swales and Feak,2000),especially in English writing in college.This study identifies the erroneous use of tense and aspect in liberal arts students' writing in comparison with that of engineering students' to examine their application ability in writing and identify areas of English learning in need of intensive instruction.This paper displays the frequency rates of errors about two English tenses(the present and the past),two aspects(the progressive and the perfect)based on an online writing corpus of students in two majors,which leads to the result that students in both majors are more likely to make mistakes in the present time and perfect aspect,liberal arts students less influenced.In addition,engineering students writing score seems to be more related to their grammatical errors than that of liberal arts students.To improve their writings,practical teaching strategies such as being aware of cross-lingual influence,practicing grammar on context level,personalized instructions,are also provided.展开更多
Background:Global evidence on the transmission of asymptomatic SARS-CoV-2 infection needs to be synthesized.Methods:A search of 4 electronic databases(PubMed,EMBASE,Cochrane Library,and Web of Science databases)as of ...Background:Global evidence on the transmission of asymptomatic SARS-CoV-2 infection needs to be synthesized.Methods:A search of 4 electronic databases(PubMed,EMBASE,Cochrane Library,and Web of Science databases)as of January 24,2021 was performed.Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines were followed.Studies which reported the transmission rate among close contacts with asymptomatic SARS-CoV-2 cases were included,and transmission activities occurred were considered.The trans-mission rates were pooled by zero-inflated beta distribution.The risk ratios(RRs)were calculated using random-effects models.Results:Of 4923 records retrieved and reviewed,15 studies including 3917 close contacts with asymptomatic indexes were eligible.The pooled transmission rates were 1.79 per 100 person-days(or 1.79%,95%confidence interval[CI]0.41%-3.16%)by asymptomatic index,which is significantly lower than by presymptomatic(5.02%,95%CI 2.37%-7.66%;p<0.001),and by symptomatic(5.27%,95%CI 2.40%-8.15%;p<0.001).Subgroup anal-yses showed that the household transmission rate of asymptomatic index was(4.22%,95%CI 0.91%-7.52%),four times significantly higher than non-household transmission(1.03%,95%CI 0.73%-1.33%;p=0.03),and the asymptomatic transmission rate in China(1.82%,95%CI 0.11%-3.53%)was lower than in other countries(2.22%,95%CI 0.67%-3.77%;p=0.01).Conclusions:People with asymptomatic SARS-CoV-2 infection are at risk of transmitting the virus to their close contacts,particularly in household settings.The transmission potential of asymptomatic infection is lower than symptomatic and presymptomatic infections.This meta-analysis provides evidence for predict-ing the epidemic trend and promulgating vaccination and other control measures.Registered with PROS-PERO International Prospective Register of Systematic Reviews,CRD42021269446;https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=269446.展开更多
To investigate formation mechanisms of secondary organic carbon（SOC） in Eastern China,measurements were conducted in an urban site in Shanghai in the summer of 2015. A period of high O3 concentrations（daily peak 〉...To investigate formation mechanisms of secondary organic carbon（SOC） in Eastern China,measurements were conducted in an urban site in Shanghai in the summer of 2015. A period of high O3 concentrations（daily peak 〉 120 ppb） was observed, during which daily maximum SOC concentrations exceeding 9.0 μg/（C·m^3）. Diurnal variations of SOC concentration and SOC/organic carbon（OC） ratio exhibited both daytime and nighttime peaks. The SOC concentrations correlated well with Ox（= O3＋ NO2） and relative humidity in the daytime and nighttime, respectively, suggesting that secondary organic aerosol formation in Shanghai is driven by both photochemical production and aqueous phase reactions. Single particle mass spectrometry was used to examine the formation pathways of SOC. Along with the daytime increase of SOC, the number fraction of elemental carbon（EC） particles coated with OC quickly increased from 38.1% to 61.9% in the size range of 250–2000 nm, which was likely due to gas-to-particle partitioning of photochemically generated semi-volatile organic compounds onto EC particles. In the nighttime, particles rich in OC components were highly hygroscopic, and number fraction of these particles correlated well with relative humidity and SOC/OC nocturnal peaks. Meanwhile, as an aqueous-phase SOC tracer, particles that contained oxalate-Fe（III） complex also peaked at night. These observations suggested that aqueous-phase processes had an important contribution to the SOC nighttime formation. The influence of aerosol acidity on SOC formation was studied by both bulk and single particle level measurements, suggesting that the aqueous-phase formation of SOC was enhanced by particle acidity.展开更多
文摘In middleschool English teaching,grammar instruction has always been an important and challenging aspect.Due to the strong influence of grammar explanation in Chinese,learning English grammar may be affected by negative transfer from their native language,which could pose certain obstacles to English acquisition.Self-efficacy,as a major emotional factor influencing learners'internal regulation strategies,has attracted wide attention from researchers both domestically and internationally for its impact on learning performance.High self-efficacy helps learners develop a more positive mindset towards learning,thereby contributing to improved learning performance.Therefore,this study focuses on investigating the relationship between grammatical self-efficacy and learning performance of English grammar among middle school students.This research contributes to a complementary understanding of grammatical self-efficacy among educators,enhancing their teaching skills,and effectively guiding students to learn English grammar with a more positive and healthy mindset,presenting a future grammar instruction in middle school English teaching.
文摘The core issue concerning the usage of tense and aspect is seen as significantly important(Michaelis,1994;Swales and Feak,2000),especially in English writing in college.This study identifies the erroneous use of tense and aspect in liberal arts students' writing in comparison with that of engineering students' to examine their application ability in writing and identify areas of English learning in need of intensive instruction.This paper displays the frequency rates of errors about two English tenses(the present and the past),two aspects(the progressive and the perfect)based on an online writing corpus of students in two majors,which leads to the result that students in both majors are more likely to make mistakes in the present time and perfect aspect,liberal arts students less influenced.In addition,engineering students writing score seems to be more related to their grammatical errors than that of liberal arts students.To improve their writings,practical teaching strategies such as being aware of cross-lingual influence,practicing grammar on context level,personalized instructions,are also provided.
文摘Background:Global evidence on the transmission of asymptomatic SARS-CoV-2 infection needs to be synthesized.Methods:A search of 4 electronic databases(PubMed,EMBASE,Cochrane Library,and Web of Science databases)as of January 24,2021 was performed.Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)guidelines were followed.Studies which reported the transmission rate among close contacts with asymptomatic SARS-CoV-2 cases were included,and transmission activities occurred were considered.The trans-mission rates were pooled by zero-inflated beta distribution.The risk ratios(RRs)were calculated using random-effects models.Results:Of 4923 records retrieved and reviewed,15 studies including 3917 close contacts with asymptomatic indexes were eligible.The pooled transmission rates were 1.79 per 100 person-days(or 1.79%,95%confidence interval[CI]0.41%-3.16%)by asymptomatic index,which is significantly lower than by presymptomatic(5.02%,95%CI 2.37%-7.66%;p<0.001),and by symptomatic(5.27%,95%CI 2.40%-8.15%;p<0.001).Subgroup anal-yses showed that the household transmission rate of asymptomatic index was(4.22%,95%CI 0.91%-7.52%),four times significantly higher than non-household transmission(1.03%,95%CI 0.73%-1.33%;p=0.03),and the asymptomatic transmission rate in China(1.82%,95%CI 0.11%-3.53%)was lower than in other countries(2.22%,95%CI 0.67%-3.77%;p=0.01).Conclusions:People with asymptomatic SARS-CoV-2 infection are at risk of transmitting the virus to their close contacts,particularly in household settings.The transmission potential of asymptomatic infection is lower than symptomatic and presymptomatic infections.This meta-analysis provides evidence for predict-ing the epidemic trend and promulgating vaccination and other control measures.Registered with PROS-PERO International Prospective Register of Systematic Reviews,CRD42021269446;https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=269446.
基金supported by the National Natural Science Foundation of China(Nos.91544224,21507010,41775150)the Ministry of Science&Technology of China(No.2012YQ220113-4)the Changjiang Scholars program of the Chinese Ministry of Education
文摘To investigate formation mechanisms of secondary organic carbon（SOC） in Eastern China,measurements were conducted in an urban site in Shanghai in the summer of 2015. A period of high O3 concentrations（daily peak 〉 120 ppb） was observed, during which daily maximum SOC concentrations exceeding 9.0 μg/（C·m^3）. Diurnal variations of SOC concentration and SOC/organic carbon（OC） ratio exhibited both daytime and nighttime peaks. The SOC concentrations correlated well with Ox（= O3＋ NO2） and relative humidity in the daytime and nighttime, respectively, suggesting that secondary organic aerosol formation in Shanghai is driven by both photochemical production and aqueous phase reactions. Single particle mass spectrometry was used to examine the formation pathways of SOC. Along with the daytime increase of SOC, the number fraction of elemental carbon（EC） particles coated with OC quickly increased from 38.1% to 61.9% in the size range of 250–2000 nm, which was likely due to gas-to-particle partitioning of photochemically generated semi-volatile organic compounds onto EC particles. In the nighttime, particles rich in OC components were highly hygroscopic, and number fraction of these particles correlated well with relative humidity and SOC/OC nocturnal peaks. Meanwhile, as an aqueous-phase SOC tracer, particles that contained oxalate-Fe（III） complex also peaked at night. These observations suggested that aqueous-phase processes had an important contribution to the SOC nighttime formation. The influence of aerosol acidity on SOC formation was studied by both bulk and single particle level measurements, suggesting that the aqueous-phase formation of SOC was enhanced by particle acidity.
