Background： Pacing, defined as percentage changes of speed between successive splits, has been extensively studied in running and cycling endurance sports; however, less information about the trends in change of spee...Background： Pacing, defined as percentage changes of speed between successive splits, has been extensively studied in running and cycling endurance sports; however, less information about the trends in change of speed during cross-country （XC） ski racing is available. Therefore, the aim of the present study was to examine the effect of performance （quartiles of race time （Q）, with Q1 the fastest and Q4 the slowest） level on pacing in the Vasaloppet ski race, the largest XC skiing race in the world. Methods： For this purpose, we analyzed female （n = 19,465） and male （n = 164,454） finishers in the Vasaloppet ski race from 2004 to 2017 using a one-way （2 sexes） analysis of variance with repeated measures to examine percentage changes of speed between 2 successive splits. Overall, the race consisted of 8 splits. Results： The race speeds of Q1, Q2, Q3, and Q4 were 13.6 ± 1.8, 10.6 ± 0.5, 9.2 ± 0.3, and 8.1 ±- 0.4 km/h, respectively, among females and 16.7 ± 1.7, 13.1 ± 0.7, 10.9 ± 0.6, and 8.9 ± 0.7 km/h, respectively, among males. The overall pacing strategy of finishers was variable. A small sex × split interaction on speed was observed （η^2= 0.016, p 〈 0.001）, with speed difference between sexes ranging from 14.9% （Split 7） to 27.0% （Split 1） and larger changes in speed between 2 successive splits being shown for females （p 〈 0.001, η^2=0.004）. A large performance × split interaction on speed, with Q1 presenting the smallest changes of speed between splits, was shown for females （η^2= 0.149, p 〈 0.001） and males （η^2 = 0.169,p 〈 0.001）. Conclusion： Male and fast XC skiers are more even pacers. Coaches and athletes should develop tailored sex- and performance-level pacing strategies; for instance, they should advise fast XC skiers to start fast and maintain their speed, rather than starting slowly and trying to make up time by going faster at times during the race.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.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
The PD（X^3∑^-） interaction potential is constructed using the CCSD（T） theory and the basis set, augcc-pV5Z. Using this potential, the spectroscopic parameters are accurately determined. The present Do, De, Re, ω...The PD（X^3∑^-） interaction potential is constructed using the CCSD（T） theory and the basis set, augcc-pV5Z. Using this potential, the spectroscopic parameters are accurately determined. The present Do, De, Re, ωe, ωeχe, αe, and Be are of 3.056 99 eV, 3.161 75 eV, 0.142 39 nm, 1701.558 cm^-1, 23.6583 cm^-1, 0.085 99 cm^-1, and 4.3963 cm^-1, respectively, which almost perfectly conform with the measurements. A total of 26 vibrational states is predicted when J = 0 by solving the radial Sehrodinger equation of nuclear motion. The complete vibrational levels, classical turning points, initial rotation and centrifugal distortion constants when J = 0 are reported for the first time, which favorably agree with the experiments. The total and various partial-wave cross sections are calculated for the elastic impact between two ground-state P and D atoms at 1.0 × 10^-12 - 1.0 × 10^-4 a.u. when they approach each other along the PD（X^3∑^-） potential. No shape resonances exist in the total elastic cross sections, though the peaks can be found for each partial wave until l=6. The shape of the total elastic cross sections is dominated by the s partial wave at very low temperatures. Due to the weakness of the shape resonances of each partial wave, they are all passed into oblivion by the strong total elastic cross sections.展开更多
One of the most important questions in the science of global change is how to balance the atmospheric CO2 budget. There is a large terrestrial missing carbon sink amounting to about one billion tonnes of carbon per an...One of the most important questions in the science of global change is how to balance the atmospheric CO2 budget. There is a large terrestrial missing carbon sink amounting to about one billion tonnes of carbon per annum. The locations, magnitudes, variations, and mechanisms responsible for this terrestrial missing carbon sink are uncertain and the focus of much continuing debate. Although the positive feedback between global change and silicate chemical weathering is used in geochemical models of atmospheric CO2, this feedback is believed to operate over a long timescale and is therefore generally left out of the current discussion of human impact upon the carbon budget. Here, we show, by synthesizing recent findings in rock weathering research and studies into biological carbon pump effects in surface aquatic ecosystems, that the carbon sink produced by carbonate weathering based on the H2O- carbonate-CO2-aquatic phototroph interaction on land not only totals half a billion tonnes per annum, but also displays a significant increasing trend under the influence of global warming and land use change; thus, it needs to be included in the global carbon budget.展开更多
Generating the rogue waves in offshore engineering is investigated,first of all,to forecast its occurrence to protect the offshore structure from being attacked,to study the mechanism and hydrodynamic properties of ro...Generating the rogue waves in offshore engineering is investigated,first of all,to forecast its occurrence to protect the offshore structure from being attacked,to study the mechanism and hydrodynamic properties of rouge wave experimentally as well as the rouge/structure interaction for the structure design.To achieve these purposes demands an accurate wave generation and calculation.In this paper,we establish a spatial domain model of fourth order nonlinear Schrdinger(NLS) equation for describing deep-water wave trains in the moving coordinate system.In order to generate rogue waves in the experimental tank efficiently,we take care that the transient water wave(TWW) determines precisely the concentration of time/place.First we simulate the three-dimensional wave using TWW in the numerical tank and modeling the deepwater basin with a double-side multi-segmented wave-maker in Shanghai Jiao Tong University(SJTU) under the linear superposing theory.To discuss its nonlinearity for guiding the experiment,we set the TWW as the initial condition of the NLS equation.The differences between the linear and nonlinear simulations are presented.Meanwhile,the characteristics of the transient water wave,including water particle velocity and wave slope,are investigated,which are important factors in safeguarding the offshore structures.展开更多
Enzymes are biomacromolecules responsible for the abundant chemical biotransformations that sustain life. Recently, biochemists have discovered that multiple conformations and numerous parallel paths are involved duri...Enzymes are biomacromolecules responsible for the abundant chemical biotransformations that sustain life. Recently, biochemists have discovered that multiple conformations and numerous parallel paths are involved during the processes catalyzed by enzymes. It is plausible that the entire macromolecular scaffold is involved in catalysis via cooperative motions that result in incredible catalytic efficiency. Moreover, some enzymes can very strongly bind the transition state with an association constant of up to 1024 M-1, suggesting that covalent bond formation is a possible process during the conversion of the transition state in enzyme catalysis, in addition to the concatenation of noncovalent interactions. Supramolecular chemistry provides fundamental knowledge about the relationships between the dynamic structures and functions of organized molecules. By tak-ing advantage of supramolecular concepts, numerous supramolecular enzyme mimics with complex and hierarchical structures have been designed and investigated. Through the study of supramolecular enzyme models, a great deal of information to aid our understanding of the mechanism of catalysis by natural enzymes has been acquired. With the development of supramolec-ular artificial enzymes, it is possible to replicate the features of natural enzymes with regards to their constitutional complexity and cooperative motions, and eventually decipher the conformation-based catalytic mystery of natural enzymes.展开更多
We study the dynamics of the multipartite systems nonresonantly interacting with electromagnetic fields, focusing on the large detuning limit for the effective Hamiltonian. Due to the many-particle interference effect...We study the dynamics of the multipartite systems nonresonantly interacting with electromagnetic fields, focusing on the large detuning limit for the effective Hamiltonian. Due to the many-particle interference effects, the more rigorous large detuning condition for neglecting the rapidly oscillating terms for the effective Plamiltonian should be △ 〉〉 N^1/2 g, instead of △ 〉〉 g usually used in the literature even in the case of multipartite systems, with N the number of microparticles involved, g the coupling strength, A the detuning. This result is significant since merely the satisfaction of the original condition will result in the invalidity of the effective Hamiltonian and the errors of the parameters associated with the detuning in the multipartite case.展开更多
文摘Background： Pacing, defined as percentage changes of speed between successive splits, has been extensively studied in running and cycling endurance sports; however, less information about the trends in change of speed during cross-country （XC） ski racing is available. Therefore, the aim of the present study was to examine the effect of performance （quartiles of race time （Q）, with Q1 the fastest and Q4 the slowest） level on pacing in the Vasaloppet ski race, the largest XC skiing race in the world. Methods： For this purpose, we analyzed female （n = 19,465） and male （n = 164,454） finishers in the Vasaloppet ski race from 2004 to 2017 using a one-way （2 sexes） analysis of variance with repeated measures to examine percentage changes of speed between 2 successive splits. Overall, the race consisted of 8 splits. Results： The race speeds of Q1, Q2, Q3, and Q4 were 13.6 ± 1.8, 10.6 ± 0.5, 9.2 ± 0.3, and 8.1 ±- 0.4 km/h, respectively, among females and 16.7 ± 1.7, 13.1 ± 0.7, 10.9 ± 0.6, and 8.9 ± 0.7 km/h, respectively, among males. The overall pacing strategy of finishers was variable. A small sex × split interaction on speed was observed （η^2= 0.016, p 〈 0.001）, with speed difference between sexes ranging from 14.9% （Split 7） to 27.0% （Split 1） and larger changes in speed between 2 successive splits being shown for females （p 〈 0.001, η^2=0.004）. A large performance × split interaction on speed, with Q1 presenting the smallest changes of speed between splits, was shown for females （η^2= 0.149, p 〈 0.001） and males （η^2 = 0.169,p 〈 0.001）. Conclusion： Male and fast XC skiers are more even pacers. Coaches and athletes should develop tailored sex- and performance-level pacing strategies; for instance, they should advise fast XC skiers to start fast and maintain their speed, rather than starting slowly and trying to make up time by going faster at times during the race.2018 Published by Elsevier B.V. on behalf of Shanghai University of Sport. This is an open access article under the CC BY-NC-ND license. （http：//creativecommons.org/licenses/by-nc-nd/4.0/）.
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
基金Supported by the Program for Science & Technology Innovation Talents in Universities of Henan Province in China under GrantNo. 2008HASTIT008the National Natural Science Foundation of China under Grant Nos. 60777012 and 10874064
文摘The PD（X^3∑^-） interaction potential is constructed using the CCSD（T） theory and the basis set, augcc-pV5Z. Using this potential, the spectroscopic parameters are accurately determined. The present Do, De, Re, ωe, ωeχe, αe, and Be are of 3.056 99 eV, 3.161 75 eV, 0.142 39 nm, 1701.558 cm^-1, 23.6583 cm^-1, 0.085 99 cm^-1, and 4.3963 cm^-1, respectively, which almost perfectly conform with the measurements. A total of 26 vibrational states is predicted when J = 0 by solving the radial Sehrodinger equation of nuclear motion. The complete vibrational levels, classical turning points, initial rotation and centrifugal distortion constants when J = 0 are reported for the first time, which favorably agree with the experiments. The total and various partial-wave cross sections are calculated for the elastic impact between two ground-state P and D atoms at 1.0 × 10^-12 - 1.0 × 10^-4 a.u. when they approach each other along the PD（X^3∑^-） potential. No shape resonances exist in the total elastic cross sections, though the peaks can be found for each partial wave until l=6. The shape of the total elastic cross sections is dominated by the s partial wave at very low temperatures. Due to the weakness of the shape resonances of each partial wave, they are all passed into oblivion by the strong total elastic cross sections.
基金supported by the National BasicResearch Program of China(2013CB956703)the National Natural Science Foundation of China(41430753 and 41172232)
文摘One of the most important questions in the science of global change is how to balance the atmospheric CO2 budget. There is a large terrestrial missing carbon sink amounting to about one billion tonnes of carbon per annum. The locations, magnitudes, variations, and mechanisms responsible for this terrestrial missing carbon sink are uncertain and the focus of much continuing debate. Although the positive feedback between global change and silicate chemical weathering is used in geochemical models of atmospheric CO2, this feedback is believed to operate over a long timescale and is therefore generally left out of the current discussion of human impact upon the carbon budget. Here, we show, by synthesizing recent findings in rock weathering research and studies into biological carbon pump effects in surface aquatic ecosystems, that the carbon sink produced by carbonate weathering based on the H2O- carbonate-CO2-aquatic phototroph interaction on land not only totals half a billion tonnes per annum, but also displays a significant increasing trend under the influence of global warming and land use change; thus, it needs to be included in the global carbon budget.
基金the "Knowledge-based Ship Design Hyper-Integrated Platform (KSHIP)",a key project of the Ministry of Education and the Ministry of Finance of China
文摘Generating the rogue waves in offshore engineering is investigated,first of all,to forecast its occurrence to protect the offshore structure from being attacked,to study the mechanism and hydrodynamic properties of rouge wave experimentally as well as the rouge/structure interaction for the structure design.To achieve these purposes demands an accurate wave generation and calculation.In this paper,we establish a spatial domain model of fourth order nonlinear Schrdinger(NLS) equation for describing deep-water wave trains in the moving coordinate system.In order to generate rogue waves in the experimental tank efficiently,we take care that the transient water wave(TWW) determines precisely the concentration of time/place.First we simulate the three-dimensional wave using TWW in the numerical tank and modeling the deepwater basin with a double-side multi-segmented wave-maker in Shanghai Jiao Tong University(SJTU) under the linear superposing theory.To discuss its nonlinearity for guiding the experiment,we set the TWW as the initial condition of the NLS equation.The differences between the linear and nonlinear simulations are presented.Meanwhile,the characteristics of the transient water wave,including water particle velocity and wave slope,are investigated,which are important factors in safeguarding the offshore structures.
基金financial support from the National Natural Science Foundation of China(91027023,21234004,21274051,21221063,21004028)the 111 project(B06009)
文摘Enzymes are biomacromolecules responsible for the abundant chemical biotransformations that sustain life. Recently, biochemists have discovered that multiple conformations and numerous parallel paths are involved during the processes catalyzed by enzymes. It is plausible that the entire macromolecular scaffold is involved in catalysis via cooperative motions that result in incredible catalytic efficiency. Moreover, some enzymes can very strongly bind the transition state with an association constant of up to 1024 M-1, suggesting that covalent bond formation is a possible process during the conversion of the transition state in enzyme catalysis, in addition to the concatenation of noncovalent interactions. Supramolecular chemistry provides fundamental knowledge about the relationships between the dynamic structures and functions of organized molecules. By tak-ing advantage of supramolecular concepts, numerous supramolecular enzyme mimics with complex and hierarchical structures have been designed and investigated. Through the study of supramolecular enzyme models, a great deal of information to aid our understanding of the mechanism of catalysis by natural enzymes has been acquired. With the development of supramolec-ular artificial enzymes, it is possible to replicate the features of natural enzymes with regards to their constitutional complexity and cooperative motions, and eventually decipher the conformation-based catalytic mystery of natural enzymes.
基金Supported by National Natural Science Foundation of China under Grant No.10774192
文摘We study the dynamics of the multipartite systems nonresonantly interacting with electromagnetic fields, focusing on the large detuning limit for the effective Hamiltonian. Due to the many-particle interference effects, the more rigorous large detuning condition for neglecting the rapidly oscillating terms for the effective Plamiltonian should be △ 〉〉 N^1/2 g, instead of △ 〉〉 g usually used in the literature even in the case of multipartite systems, with N the number of microparticles involved, g the coupling strength, A the detuning. This result is significant since merely the satisfaction of the original condition will result in the invalidity of the effective Hamiltonian and the errors of the parameters associated with the detuning in the multipartite case.
