因果要素关联视域下社交媒体倦怠用户画像模型构建

[目的/意义]探究社交媒体倦怠的原因要素和结果要素标签，分析各要素间的相互作用关系，扩展用户信息行为的理论研究范畴，为企业深入了解用户社交媒体倦怠发展态势提供指导。[方法/过程]基于信息生态理论，提取"信息人、信息、信息环境和信息技术"4个信息生态因子维度的社交媒体用户画像标签；根据用户心理特征和行为表现，抽取用户画像情感和行为标签，构建社交媒体倦怠用户画像模型。[结果/结论]透过社交媒体用户消极使用和负面情感变化的典型社会现象，对用户画像模型进行整合分析与关系凝练，证明本研究社交媒体倦怠用户画像模型与S-S-O理论框架具有一致性，并根据实际进行理论上的拓展和应用。     

Neuro-mechanical adjustments to shod versus barefoot treadmill runs in the acute and delayed stretch-shortening cycle recovery phases

In habitually shod recreational runners, we studied the combined influence of footwear and stretch-shortening cycle (SSC) fatigue on treadmill running pattern, paying special attention to neuro-mechanical adjustments in the acute and 2-day delayed recovery periods. The SSC exercise consisted of a series of 25 sub-maximal rebounds on a sledge apparatus repeated until exhaustion. The acute and delayed functional fatigue effects were quantified in a maximal drop jump test. The neuro-mechanical adjustments to fatigue were examined during two submaximal treadmill run tests of 3 min performed either barefoot or with shoes on. Surface electromyographic (EMG) activities, tibial accelerations and kinematics of the right lower limb were recorded during the first and last 15 s of each run. The main result was that neuro-mechanical differences between the shod and barefoot running patterns, classically reported in the absence of fatigue, persisted in the fatigued state. However, in the delayed recovery phase, rearfoot eversion was found to significantly increase in the shod condition. This specific footwear effect is considered as a potential risk factor of overuse injuries in longer runs. Therefore, specific care should be addressed in the delayed recovery phase of SSC fatigue and the use of motion control shoes could be of interest.     

Comment on: Forearm oxygenation and blood flow kinetics during a sustained contraction in multiple ability groups of rock climbers

We read with interest the authors’ paper on this important area of climbing physiology. We however wish to highlight the incorrect identification of flexor carpi radialis (FCR) as a finger flexor and the implications it has for the conclusions described. FCR is a wrist flexor and has no direct bearing on flexion of the fingers during a climbing grip and thus could be expected to have a reduced oxygenation response compared to flexor digitorum profundus. We also would like to seek clarification from the authors regarding their confidence in their method for locating the two muscles under investigation as we feel this may not be accurately possible using the method described.     

The effects of physical contact type on the internal and external demands during a rugby league match simulation protocol

The aim of this study was to investigate how the type of contact influences physiological, perceptual and locomotive load during a simulated rugby league match. Eleven male university rugby league players performed two trials of the rugby league movement simulation protocol for interchange forwards with a traditional soft tackle bag and a weighted tackle sled to replicate contact demands. The interchange forward-specific simulation was chosen given the contact frequency is higher for this group of players compared to whole match players. Locomotive rate, sprint speed, tackle intensity, heart rate (HR) and rating of perceived exertion were analysed during the first and second bouts that replicated two ~23 min on-field passages. Countermovement jump (CMJ) was measured before and immediately after each trial. More time was spent in heart rate zone between 91 and 100% HR_peak during the first (effect size ± 90% confidence interval: 0.44 ± 0.49) and second bouts (0.44 ± 0.43), and larger (0.6 ± 0.69) decrements in CMJ performance were observed during the sled trial (5.9, s = 4.9%) compared to the bag trial (2.6, s = 5.4%). Changing the type of contact during the match simulation subtly altered both the internal and external loads on participants. Using a standard tackle bag results in faster sprint speed to contact, but lower overall high-intensity running. Conversely, a heavier tackle object increases the internal load and results in greater lower limb neuromuscular fatigue as reflected by the decrease in CMJ performance.     

Effects of load mass carried in a backpack upon respiratory muscle fatigue

Purpose: The purpose of this study was to investigate whether loads carried in a backpack, with a load mass ranging from 0 to 20?kg, causes respiratory muscle fatigue. Methods: Eight males performed four randomised load carriage (LC) trials comprising 60?min walking at 6.5?km?h^?1 wearing a backpack of either 0 (LC₀), 10 (LC₁₀), 15 (LC₁₅) or 20?kg (LC₂₀). Inspiratory (P_Imax) and expiratory (P_Emax) mouth pressures were assessed prior to and immediately following each trial. Pulmonary gas exchange, heart rate (HR), blood lactate and glucose concentration and perceptual responses were recorded during the first and final 60?s of each trial. Results: Group mean P_Imax and P_Emax were unchanged following 60-min load carriage in all conditions (p?>?.05). There was an increase over time in pulmonary gas exchange, HR and perceptions of effort relative to baseline measures during each trial (p?p?>?.05). Conclusions: These findings indicate that sub-maximal walking with no load or carrying 10, 15 or 20?kg in a backpack for up to 60?min does not cause respiratory muscle fatigue despite causing an increase in physiological, metabolic and perceptual parameters.     

Cr3锻钢平整工作辊"桔皮"原因分析及改进措施

某热轧带钢厂Cr3材质锻钢平整工作辊每次上机服役仅生产1000t钢卷即需换辊修磨，严重影响产品质量和轧辊使用寿命。对Cr3材质锻钢工作辊进行硬度、金相组织等检验发现，虽然辊面金相组织正常，但是硬度偏低，导致在使用过程中出现塑性变形，表明这种材质的工作辊不适合在“干”平整的工况条件下用作热轧平整工作辊。建议采用具有更高耐磨性、更高热稳定性的高速工具钢、半高速工具钢和改进型高NiCr无限冷硬铸铁工作辊等材质工作辊代替Cr3材质锻钢工作辊，以提高生产效率和轧辊寿命。     

对外汉语教学中语法教学的若干问题

现行的对外汉语教学存在着不少的问题。仅语法方面的教学就存在两大问题。首先 ,对外汉语教学应是教学语法的教学 ,而不是理论语法。再次 ,汉语语法更是讲条件的语法。因此 ,在教授外国人汉语的时候 ,语法的深入和细化是极其重要的     

高校非教师系列基层工作人员职业倦怠审视与分析

高校非教师系列基层工作人员的职业倦怠现象已日益突出。职业的社会认同感低、工作压力大、发展空间小、校内管理体制与评价体系等都是造成职业倦怠的原因,建议从强化职业认同感、满足个体的基本需要及个人努力等方面对进行心理调适。     

高校大学生运动训练疲劳应对分析——以广西第十二届民运会广西民族大学参赛学生为例

竞技体育快速发展,运动员为了取得优异的比赛成绩要长期承受大运动量、高负荷的训练。运动员训练过程中产生的疲劳现象主要与成就感的降低、情绪/体力耗竭和对运动的负评价程度相关。改善运动员心理承受能力和应变能力,减轻心理负担,根据个体运动潜力进行针对性训练,科学安排训练量、训练强度和训练时间等可以提高训练效率。