基于需求导向的旅游政务微博公共信息服务质量优化研究——以山东旅游政务微博为例

旅游政务微博已成为政府官方旅游机构发布和传播旅游信息的重要载体,其信息服务质量的优化对于完善旅游信息服务体系建设和提升旅游品牌形象尤为关键。本研究借鉴扎根理论,对游客的网络评论数据进行三级编码,归纳了网络游客信息需求的4个核心范畴,从而构建了旅游政务微博公共信息服务质量优化的理论模型,最终依据模型提出相关的优化建议。     

Effect of 6-weeks WBVT on the behaviour of the lower limb muscle fibres during vertical jumping

The purpose of the current study was to examine the effect of 6 weeks of whole body vibration training (WBVT) on body composition, muscle activity of the gastrocnemius and vastus lateralis, gastrocnemius muscle architecture (static and dynamic) and ground reaction forces (performance jump) during the take-off phase of a countermovement jump in young healthy adult males. A total of 33 men (23.31 ± 5.62 years) were randomly assigned to a whole body vibration group (experimental group, EG_WBVT: n = 17; 22.11 ± 4.97 years) or a control group (CG: n = 16; 24.5 ± 6.27 years). The total duration of the intervention phase (WBVT) was 6 weeks with a frequency of 3 sessions per week. Statistically significant differences were observed (P ≤ 0.05) between pre- and post-test in the power peak (Δ 1.91 W · kg^?1; P = 0.001), take-off velocity (0.1 cm · s^?1; P = 0.002) and jump height (Δ 0.4 cm; P = 0.002) for EG_WBVT. There were no statistically significant differences in any of the body composition and muscle architecture variables. Moreover, no significant differences were found between EG_WBVT and CG nor changes in muscle activity during take-off phase of the gastrocnemius and vastus lateralis pre- versus post-training. This study suggests that a 6-week WBVT programme with increasing intensity improves jump performance but does not alter muscle activity nor muscle architecture in healthy young men.     

用ZMNL方法实现地面杂波的建模与仿真

应用零记忆非线性变换法(ZMNL),对幅度分布特性为瑞利分布、对数正态分布和韦伯分布,功率谱特性为高斯谱和平方谱的地杂波进行建模和仿真.实现了实时动态地模拟实际采集的雷达地杂波,而且可按给定的功率谱模型产生满足非高斯分布的随机数据序列.仿真结果和理想模型的吻合,证明了ZMNL是有效的地杂波仿真方法.最后研究了ZMNL方法产生误差的原因,以及ZMNL方法的适用范围.     

异中求同：鲁迅与创造社、太阳社的论争——鲁迅与中国左翼文学的发生之二

1928年,鲁迅与创造社、太阳社发生了革命文学论争,这场论争给双方乃至整个左翼文艺界留下了深刻的教训,但“异中求同”使双方实现了“人和”。使左翼文艺界内部的原动力被激活,使左翼文艺界实现了“优胜劣汰”,使进步知识界明确、认同了无产阶级文艺和文化的存在合理性,进而为中国左翼文学的发生奠定了坚实的理论基础和相应的舆论准备。     

三峡库区岩溶型地面塌陷形成机理及特点

三峡库区岩溶型地面塌陷问题影响到三峡工程的顺利进行,正确掌握它的形成机理及特点有利于其地质灾害的预防。以奉节新县城为例,从地形地貌、地层岩性、微构造及水文地质几方面论述其形成机理,并认为溶蚀作用是形成地面塌陷的关键因素 同时总结了地面塌陷的几大特点。     

Use of probabilistic and deterministic measures to identify unfavorable earthquake records

This study introduces measures to identify resonant （concentration of energy in a single or a few frequencies） or unfavorable earthquake ground motions. Probabilistic measures based on the entropy rate and the geometric properties of the power spectral density function （PSDF） of the ground acceleration are developed first. Subsequently, deterministic measures for the frequency content of the ground acceleration are also developed. These measures are then used for identifying resonance and criticality in stochastic earthquake models and 110 acceleration records measured at rock, stiff, medium and soft soil sites. The unfavorable earthquake record for a given structure is defined as the record having a narrow frequency content and dominant frequency close to the structure fundamental natural frequency. Accordingly, the measures developed in this study may provide a basis for selecting records that are capable of producing the highest structural response. Numerical verifications are provided on damage caused to structures by identified resonant records.     

Cardiopulmonary loading in motocross riding

Abstract

The present study was designed to examine physiological responses during motocross riding. Nine Finnish A-level motocross riders performed a 15-min ride at a motocross track and a test of maximal oxygen uptake ([Vdot]O_2max) in the laboratory. Cardiopulmonary strain was measured continuously during the ride as well as in the [Vdot]O_2max test. During the ride, mean [Vdot]O₂ was 32 ml · kg^?1 · min^?1 (s = 4), which was 71% (s = 12) of maximum, while ventilation (V _E) was 73% (s = 15) of its maximum. The relative [Vdot]O₂ and V _E values during the riding correlated with successful riding performance (r = 0.80, P < 0.01 and r = 0.79, P < 0.01, respectively). Mean heart rate was maintained at 95% (s = 7) of its maximum. Mean blood lactate concentration was 5.0 mmol · l^?1 (s = 2.0) after the ride. A reduction of 16% (P < 0.001) in maximal isometric handgrip force was observed. In conclusion, motocross causes riders great physical stress. Both aerobic and anaerobic metabolism is required for the isometric and dynamic muscle actions experienced during a ride.     

Mechanics of Batting: Effect of Stride Technique on Ground Reaction Forces and Bat Velocities

The benefits associated with being physically active are well documented, but a significant proportion of the population is insufficiently active. Physical inactivity is a major health risk factor in our society, and physical education programs are consistently identified as a means to address this concern. The purpose of this article is to use the social-ecological model as a framework to examine ways in which physical education programs can play an important role in promoting physical activity. Policies that require time allocations and resources for physical education and physical activity in schools and community designs that provide infrastructure that makes being physically active accessible and convenient are important factors in making schools and communities healthier spaces. It is clear, however, that policies alone are not sufficient to address concerns about physical inactivity. We must consider individual factors that influence decisions to be physically active in efforts to engage children in physical education programs that promote active lifestyles. The learning climate that teachers create determines what students do and learn in physical education classes. Ensuring that students see value in the content presented and structuring classes so that students believe they can experience success when they exert effort are key elements in an effective motivational climate. Efforts to address public health concerns about physical inactivity require a comprehensive approach including quality physical education. It is critical that kinesiology professionals emerge as leaders in these efforts to place physical education programs at the center of promoting children's physical activity.     

The Kinematics and Kinetics of the Running Pattern of Two-, Four-, and Six-Year-Old Children

Abstract

Selected kinematic and kinetic variables in the running pattern of 2-, 4-, and 6-year-old children were investigated. Cinematographic records and force-plate tracings were used to study the running patterns of the 28 Caucasian subjects, 15 male and 13 female. A 2 × 3 (sex × age) factorial analysis of variance was used to determine whether effects of variation between and within age and sex factors for each of the dependent variables of selected kinematic (displacement and velocity) and kinetic (ground reaction force) variables were significant. The running speeds improved with age. Although height and weight gains influenced the improvement shown in performance, certain biomechanical variables also contributed to the development of the running pattern. In the majority of the selected kinematic and kinetic variables there were significant differences between the 2-year-old group and the other two groups. Where there were significant differences in the variables, the differences tended to be in displacement, velocity, and magnitude of force measures, rather than in time of occurrence measures. Significant differences between male and female subjects appeared in five kinematic variables related to the swing leg.     

我国公共体育场地的现状研究

运用文献资料、数理统计、专家访谈和逻辑分析等研究方法,根据第五次全国体育场地普查数据资料,从场地类型、分布状况、隶属关系、经济成分、投资方式、场地使用率等方面对我国公共体育场地的现状进行分析。