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
Purpose. To investigate the peak latency of the orbital presaccadic spike potential (SP) with horizontal eye movement in normals.Methods. Orbital SP was recorded in 28 normal subjects from 8 electrodes around the eyes...Purpose. To investigate the peak latency of the orbital presaccadic spike potential (SP) with horizontal eye movement in normals.Methods. Orbital SP was recorded in 28 normal subjects from 8 electrodes around the eyes with Pz as the reference while performing 5°, 10°, 20°, 30° and 40°horizontal saccades to visual targets. SP peak latency was measured from SP onset to SP peak on averaged data aligned on SP peak.Results. Significant main effects on SP peak latency are found for saccade size (<0. 01), saccade direction (P<0. 01) and electrode site (P<0. 05). No significant main effect on SP peak latency is found for eye (P>0. 05). SP peak latency increases with increasing saccade size from 5°to 40°. SP peak latency is longer with saccades back to center than away from center, and with abducting saccades than with adducting saccades. SP peak latency differs at the electrode sites with an order from shorter to longer as follows: inner canthus (IC); inferior orbit (IO): outer canthus (OC); superior orbit (SO).Conclusicos. The effects on the peak latency of orbital SP can be explained by the saccade dynamic property, volume conduction as well as physiologic and anatomic factors of the eyes and orbits. The peak latency of orbital SP can be used to reflect the temporal characteristics of ocular motor units controlling saccadic eye movement.展开更多
Hannah Arendt, the new film by the German director Margarethe Von Trotta, does not seem just like another trying to represent philosophy through the classic cinematic storytelling. It builds instead a perfect dialogue...Hannah Arendt, the new film by the German director Margarethe Von Trotta, does not seem just like another trying to represent philosophy through the classic cinematic storytelling. It builds instead a perfect dialogue between these two practices that never encroach each other： There is not any doctrine that prevents cinema＇s freedom to create images and any philosophy claim that forces cinema to find in images an alternative way of expression. Von Trotta leaves any biopic form and stages a harmonic building where cinema fulfills philosophy and philosophy fulfills cinema. In this way she gets an outright practical exhibition of a theory, the ＂banality of evil＂. We want to comprehend the reasons of this perfect building analyzing this film, its characters with their acts, all the images their montage, and editing, everything that supports the Arendt＇s philosophical notion. We work on the film with the philosophical categories created by Gilles Deleuze to study the history of cinema in two essays, Image-mouvement and Image-time. In this way we can unfold how Margarethe Von Trotta represents a theory through images, without any word as intermediary展开更多
This paper studies the adiabatic dynamics of the breather soliton of the sine-Gordon equation. The integrals of motion are found and then used in soliton perturbation theory to derive the differential equation governi...This paper studies the adiabatic dynamics of the breather soliton of the sine-Gordon equation. The integrals of motion are found and then used in soliton perturbation theory to derive the differential equation governing the soliton velocity. Time-dependent functions arise and their properties are studied. These functions are found to be bounded and periodic and affect the soliton velocity. The soliton velocity is numerically plotted against time for different combinations of initial velocities and perturbation terms.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Purpose. To investigate the peak latency of the orbital presaccadic spike potential (SP) with horizontal eye movement in normals.Methods. Orbital SP was recorded in 28 normal subjects from 8 electrodes around the eyes with Pz as the reference while performing 5°, 10°, 20°, 30° and 40°horizontal saccades to visual targets. SP peak latency was measured from SP onset to SP peak on averaged data aligned on SP peak.Results. Significant main effects on SP peak latency are found for saccade size (<0. 01), saccade direction (P<0. 01) and electrode site (P<0. 05). No significant main effect on SP peak latency is found for eye (P>0. 05). SP peak latency increases with increasing saccade size from 5°to 40°. SP peak latency is longer with saccades back to center than away from center, and with abducting saccades than with adducting saccades. SP peak latency differs at the electrode sites with an order from shorter to longer as follows: inner canthus (IC); inferior orbit (IO): outer canthus (OC); superior orbit (SO).Conclusicos. The effects on the peak latency of orbital SP can be explained by the saccade dynamic property, volume conduction as well as physiologic and anatomic factors of the eyes and orbits. The peak latency of orbital SP can be used to reflect the temporal characteristics of ocular motor units controlling saccadic eye movement.
文摘Hannah Arendt, the new film by the German director Margarethe Von Trotta, does not seem just like another trying to represent philosophy through the classic cinematic storytelling. It builds instead a perfect dialogue between these two practices that never encroach each other： There is not any doctrine that prevents cinema＇s freedom to create images and any philosophy claim that forces cinema to find in images an alternative way of expression. Von Trotta leaves any biopic form and stages a harmonic building where cinema fulfills philosophy and philosophy fulfills cinema. In this way she gets an outright practical exhibition of a theory, the ＂banality of evil＂. We want to comprehend the reasons of this perfect building analyzing this film, its characters with their acts, all the images their montage, and editing, everything that supports the Arendt＇s philosophical notion. We work on the film with the philosophical categories created by Gilles Deleuze to study the history of cinema in two essays, Image-mouvement and Image-time. In this way we can unfold how Margarethe Von Trotta represents a theory through images, without any word as intermediary
文摘This paper studies the adiabatic dynamics of the breather soliton of the sine-Gordon equation. The integrals of motion are found and then used in soliton perturbation theory to derive the differential equation governing the soliton velocity. Time-dependent functions arise and their properties are studied. These functions are found to be bounded and periodic and affect the soliton velocity. The soliton velocity is numerically plotted against time for different combinations of initial velocities and perturbation terms.
