Evaluation on nitrogen removal of step-feed anoxic/oxic activated sludge process at the standpoint of reaction kinetics and process kinetics was conducted. Theoretical biological nitrogen removal efficiency was deduce...Evaluation on nitrogen removal of step-feed anoxic/oxic activated sludge process at the standpoint of reaction kinetics and process kinetics was conducted. Theoretical biological nitrogen removal efficiency was deduced based on the mass balance of nitrate in the last stage. The comparison of pre-denitrification process and step feed process in the aspects of nitrogen removal efficiency, volume of reactor and building investment was studied, and the results indicated that step-feed anoxic/oxic activated sludge process was superior to pre-denitrification process in these aspects.展开更多
Sperm motility is important in reproductive biology. To understand the physiological ecology characteristics of sperm of Sepiella maindroni, we studied the activation rate, active time, and lifespan of sperm to evalua...Sperm motility is important in reproductive biology. To understand the physiological ecology characteristics of sperm of Sepiella maindroni, we studied the activation rate, active time, and lifespan of sperm to evaluate the influence of external factors, including temperature, salinity, pH, glucose, NaCl, KCl, MgCl2, CaCl2, EDTA-2Na and artificial seawater on sperm motility. The results show that the appropriate activation and motility condition for sperm were： temperature 20-30℃ （optimum 25℃）, salinity 10.6-30.6 （optimum 15.9） and pH 8.0-8.6 （optimum 8.0-8.4）. Sperm activity varied in different concentrations of glucose, NaCl, KCl, MgCl2 and CaCl〉 None of the selected concentrations of EDTA-2Na solution could activate the sperm. The activation rate in artificial seawater devoid of Ca2＋, Mg2＋ or HCO3- was low. The results should help further studies on the preservation and activation of squid sperm.展开更多
Background：Little is known about change in physical activity（PA） and its relationship to all-cause mortality among old people.There is even less information about the association between PA,fitness and all-cause mo...Background：Little is known about change in physical activity（PA） and its relationship to all-cause mortality among old people.There is even less information about the association between PA,fitness and all-cause mortality among people aged 80 years and above.The objective is to investigate persistence and change in PA over 5 years as a predictor of all-cause mortality,and fitnes as a mediator of this association,among people aged 80 and 85 years at the beginning of an 18-year mortality follow-up period.Methods：Using Evergreen Project data（started in 1989）,4 study groups were formed according to self-reported changes in PA level,over a 5-year period（starting in 1989–1990 and ending in 1994–1995）：remained active（RA,control group）,changed to inactive（CI）,remained inactive（RI）,and changed to active（CA）.Mortality was followed up over the 18-year period（1994–2012）.Cox models with different covariates such as age,sex,use of alcohol,smoking,chronic diseases,and a 10 m walking test were used to analyze the association between change in PA level and mortality.Results：Compared to RA,those who decreased their PA level（CI） between baseline and follow-up had higher all-cause mortality（hazard ratio（HR=2.09;95%CI：1.63–2.69） when adjusted for age,gender,and chronic diseases.RI showed the highest all-cause mortality（HR = 2.16;95%CI：1.59–2.93）.In CA,when compared against RA,the risk of all-cause mortality was not statistically significan（HR=1.51;95%CI：0.95–2.38）.In comparison with RA,when walking speed over 10 m was added as a covariate,all-cause mortality risk was almost statistically significan only in CI（HR=1.37;95%CI：1.00–1.87）.Conclusion：Persistence and change in PA level was associated with mortality.This association was largely explained by fitnes status.Randomized controlled studies are needed to test whether maintaining or increasing PA level could lengthen the life of old people.展开更多
Schema is known to play an important role in reading comprehension. The schema embodying the learners background knowledge of cultural familiar materials facilitates the understanding of the text （Pritchard, 1990）. ...Schema is known to play an important role in reading comprehension. The schema embodying the learners background knowledge of cultural familiar materials facilitates the understanding of the text （Pritchard, 1990）. Also Steffensen, Joag-Dev, and Anderson （1979） and Nelson （1987） proposed that the schemata embodying background knowledge influenced how well the text would be comprehended. However, Hudson （1982） and Carrell （1984） found there was no significant background effect in advanced level learners. From those studies, it seems that background effect is different at different language proficiency levels. Thus, the present study examines the interaction between background knowledge and language proficiency in reading comprehension. The participants were freshmen of National Chiayi University. They were divided into three language proficiency levels based on the General English Proficiency Test. Four reading comprehension tests were constructed to assess their reading comprehension： cultural familiar/unfamiliar text and topic familiar/unfamiliar text. The results of this study showed that participants had better performance on the culture/topic familiar text than the culture/topic unfamiliar text. Thus the findings suggest that the teacher can use teaching activities, such as pre-reading activities or vocabulary teaching to increase the background knowledge when teaching readings to EFL （English as a foreign language） learners展开更多
文摘Evaluation on nitrogen removal of step-feed anoxic/oxic activated sludge process at the standpoint of reaction kinetics and process kinetics was conducted. Theoretical biological nitrogen removal efficiency was deduced based on the mass balance of nitrate in the last stage. The comparison of pre-denitrification process and step feed process in the aspects of nitrogen removal efficiency, volume of reactor and building investment was studied, and the results indicated that step-feed anoxic/oxic activated sludge process was superior to pre-denitrification process in these aspects.
基金Supported by the National Natural Science Foundation of China (No.40646030)the National Agriculture Science and Technology Achievements Transfer Capital (No.2009GB2C2204)the Major Project of Zhejiang Province (No.2007C12061)
文摘Sperm motility is important in reproductive biology. To understand the physiological ecology characteristics of sperm of Sepiella maindroni, we studied the activation rate, active time, and lifespan of sperm to evaluate the influence of external factors, including temperature, salinity, pH, glucose, NaCl, KCl, MgCl2, CaCl2, EDTA-2Na and artificial seawater on sperm motility. The results show that the appropriate activation and motility condition for sperm were： temperature 20-30℃ （optimum 25℃）, salinity 10.6-30.6 （optimum 15.9） and pH 8.0-8.6 （optimum 8.0-8.4）. Sperm activity varied in different concentrations of glucose, NaCl, KCl, MgCl2 and CaCl〉 None of the selected concentrations of EDTA-2Na solution could activate the sperm. The activation rate in artificial seawater devoid of Ca2＋, Mg2＋ or HCO3- was low. The results should help further studies on the preservation and activation of squid sperm.
文摘Background：Little is known about change in physical activity（PA） and its relationship to all-cause mortality among old people.There is even less information about the association between PA,fitness and all-cause mortality among people aged 80 years and above.The objective is to investigate persistence and change in PA over 5 years as a predictor of all-cause mortality,and fitnes as a mediator of this association,among people aged 80 and 85 years at the beginning of an 18-year mortality follow-up period.Methods：Using Evergreen Project data（started in 1989）,4 study groups were formed according to self-reported changes in PA level,over a 5-year period（starting in 1989–1990 and ending in 1994–1995）：remained active（RA,control group）,changed to inactive（CI）,remained inactive（RI）,and changed to active（CA）.Mortality was followed up over the 18-year period（1994–2012）.Cox models with different covariates such as age,sex,use of alcohol,smoking,chronic diseases,and a 10 m walking test were used to analyze the association between change in PA level and mortality.Results：Compared to RA,those who decreased their PA level（CI） between baseline and follow-up had higher all-cause mortality（hazard ratio（HR=2.09;95%CI：1.63–2.69） when adjusted for age,gender,and chronic diseases.RI showed the highest all-cause mortality（HR = 2.16;95%CI：1.59–2.93）.In CA,when compared against RA,the risk of all-cause mortality was not statistically significan（HR=1.51;95%CI：0.95–2.38）.In comparison with RA,when walking speed over 10 m was added as a covariate,all-cause mortality risk was almost statistically significan only in CI（HR=1.37;95%CI：1.00–1.87）.Conclusion：Persistence and change in PA level was associated with mortality.This association was largely explained by fitnes status.Randomized controlled studies are needed to test whether maintaining or increasing PA level could lengthen the life of old people.
文摘Schema is known to play an important role in reading comprehension. The schema embodying the learners background knowledge of cultural familiar materials facilitates the understanding of the text （Pritchard, 1990）. Also Steffensen, Joag-Dev, and Anderson （1979） and Nelson （1987） proposed that the schemata embodying background knowledge influenced how well the text would be comprehended. However, Hudson （1982） and Carrell （1984） found there was no significant background effect in advanced level learners. From those studies, it seems that background effect is different at different language proficiency levels. Thus, the present study examines the interaction between background knowledge and language proficiency in reading comprehension. The participants were freshmen of National Chiayi University. They were divided into three language proficiency levels based on the General English Proficiency Test. Four reading comprehension tests were constructed to assess their reading comprehension： cultural familiar/unfamiliar text and topic familiar/unfamiliar text. The results of this study showed that participants had better performance on the culture/topic familiar text than the culture/topic unfamiliar text. Thus the findings suggest that the teacher can use teaching activities, such as pre-reading activities or vocabulary teaching to increase the background knowledge when teaching readings to EFL （English as a foreign language） learners
