Investigating cycling kinematics and braking maneuvers in the real world: e-bikes make cyclists move faster,brake harder,and experience new conflicts

Pedelecs (e-bikes), which facilitate higher speeds with less effort in comparison to traditional bicycles (t-bikes), have grown considerably in popularity in recent years. Despite the large expansion of this new transportation mode, little is known about the behavior of e-cyclists, or whether cycling an e-bike increases crash risk and the likelihood of conflicts with other road users, compared to cycling on t-bikes. In order to support the design of safety measures and to maximize the benefits of e-bike use, it is critical to investigate the real-world behavior of riders as a result of switching from t-bikes to e-bikes.Naturalistic studies provide an unequaled method for investigating rider cycling behavior and bicycle kinematics in the real world in which the cyclist regularly experiences traffic conflicts and may need to perform avoidance maneuvers, such as hard braking, to avoid crashing. In this paper we investigate cycling kinematics and braking events from naturalistic data to determine the extent to which cyclist behavior changes as a result of transferring from t-bikes to e-bikes, and whether such change influences cycling safety.Data from the BikeSAFE and E-bikeSAFE naturalistic studies were used in this investigation to evaluate possible changes in the behavior of six cyclists riding t-bikes in the first study and e-bikes in the second one. Individual cyclists’ kinematics were compared between bicycle types. In addition, a total of 5092 braking events were automatically extracted after identification of dynamic triggers. The 286 harshest braking events (136 cases for t-bike and 150 for e-bike) were then validated and coded via video inspection.Results revealed that each of the cyclists rode faster on the e-bike than on the t-bike, increasing his/her average speed by 2.9–5.0 km/h. Riding an e-bike also increased the probability to unexpectedly have to brake hard (odds ratio = 1.72). In addition, the risk of confronting abrupt braking and sharp deceleration were higher when riding an e-bike than when riding a t-bike.Our findings provide evidence that cyclists’ behavior and the way cyclists interact with other road users change when cyclists switch from t-bikes to e-bikes. Because of the higher velocity, when on e-bikes, cyclists appear to have harder time predicting movements within the traffic environment and, as a result, they need to brake abruptly more often to avoid collisions, compared with cycling on t-bikes. This study provides new insights into the potential impact on safety that a cycling society moving to e-bikes may have, indicating that e-cycling requires more reactive maneuvers than does cycling traditional bicycles and suggesting that any distractive activity may be more critical when riding e-bikes compared to traditional bikes.     

An Evaluation of the Word Triad Method for Monitoring Spelling Progress

Although spelling skill progress has typically been studied within the context of students' responses to written story starters (Deno, Marsten, & Mirkin, 1982; Fuchs & Fuchs, 2011; Hosp, Hosp, & Howell, 2007; Shinn & Shinn, 2002), there has been little research conducted within a curriculum-based measurement framework that has studied spelling progress monitoring on a weekly basis throughout an entire school year. The authors evaluated spelling progress using word triads, defined as a group of 3 words (with the same number of letters) that have a similar phonetic or morphological structure. Successful spelling of word triads as the unit of analysis has the potential to be more useful diagnostically to teachers than successful spelling of single words as the unit of analysis. An alternating series of three 15-word spelling tests were administered weekly to 10 third- and fourth-grade classrooms in the same school district throughout the school year for 8 rounds (1 round = 3 weeks of different but phonetically and/or morphologically similar word lists). Results indicate steady progress throughout the school year in the correct spelling of word triads (despite teacher reporting of no explicit spelling instruction in classrooms using in the words employed in the study). Correlations between the number of correctly spelled word triads with standard scores from a group-administered communication arts test were significant and comparable to alternate spelling test scoring methods. The authors conclude with limitations of the study and implications for practitioners.     

越轨同伴交往与青少年睡眠问题的交叉滞后分析

本研究采用交叉滞后设计探讨越轨同伴交往与青少年睡眠问题之间的双向关系。通过越轨同伴交往问卷与匹兹堡睡眠质量指数（PSQI）对广东省某地区887名青少年（43.90%男生; M = 15.55）进行为期一学年的追踪研究。在控制了性别、年龄后,结果发现:（1）学年初始的睡眠问题可以显著正向预测青少年学年末的越轨同伴交往（b2 = 0.12, SE = .05, p < .05）,即青少年在学年初始睡眠问题越多,学年末则表现出更多的越轨同伴交往;（2）研究并未发现学年初始的青少年越轨同伴交往可以显著预测其学年末的睡眠问题（b1 = –0.07, SE = .06, p > .05）。因此,本研究的结果支持了睡眠问题对青少年越轨同伴交往的单向预测作用,即睡眠问题可能是增加青少年越轨同伴交往的重要风险因素之一。     

Testing autocorrelation and partial autocorrelation: Asymptotic methods versus resampling techniques

Autocorrelation and partial autocorrelation, which provide a mathematical tool to understand repeating patterns in time series data, are often used to facilitate the identification of model orders of time series models (e.g., moving average and autoregressive models). Asymptotic methods for testing autocorrelation and partial autocorrelation such as the 1/T approximation method and the Bartlett's formula method may fail in finite samples and are vulnerable to non-normality. Resampling techniques such as the moving block bootstrap and the surrogate data method are competitive alternatives. In this study, we use a Monte Carlo simulation study and a real data example to compare asymptotic methods with the aforementioned resampling techniques. For each resampling technique, we consider both the percentile method and the bias-corrected and accelerated method for interval construction. Simulation results show that the surrogate data method with percentile intervals yields better performance than the other methods. An R package pautocorr is used to carry out tests evaluated in this study.     

Looking forward: the effects of photographs on the qualities of future thinking

Future episodic thinking relies on the reconstruction of remembered experiences. Photographs provide one means of remembering, acting as a “cognitive springboard” for generating related memory qualities. We wondered whether photographs would also invite embellishment of future thought qualities, particularly in the presence (or absence) of associated memories. In two studies participants generated future events in familiar (associated memories) and novel (no associated memories) locations. Half of the participants viewed scene location photographs during event generation. All participants then imagined the events for one minute and completed a self-report measure of content qualities. Results of the current set of studies suggested that for novel locations, no differences in qualities emerged; however, for familiar locations, photographs did not enhance qualities and, in some cases, actually constrained perceptual (Experiments 1 and 2) and sensory (Experiment 1) detail ratings of future thoughts. Thus, photographs did not invite embellishment of future thought details.     

家庭功能与青少年消极冒险行为的关系:一个有调节的中介模型

为探讨家庭功能影响青少年消极冒险行为的作用机制及条件,采用青少年冒险行为问卷、家庭功能问卷、自尊问卷、同伴群体特征问卷对山东省日照市940名初高中学生进行调查。结果发现:(1)家庭功能不良不仅可直接预测青少年更多的消极冒险行为,而且也可通过使青少年交往更多不良同伴进而使其冒险行为进一步增多;(2)不良同伴交往对青少年消极冒险行为的预测受到个体自尊的调节。低自尊个体更容易受到不良同伴交往的影响而发生更多的消极冒险行为,表现出两风险因素的叠加效应。研究结果提示,家庭是青少年健康成长的基础,家庭功能不良可使青少年适应不良,塑造良好的同伴环境、培养良好的自我素质或可降低这一风险。     

A meta‐analysis of the differential relations of traditional and cyber‐victimization with internalizing problems

This meta‐analysis examined the associations between cyber‐victimization and internalizing problems controlling for the occurrence of traditional victimization. Twenty independent samples with a total of 90,877 participants were included. Results confirmed the significant intercorrelation between traditional and cyber‐victimization (r = .43). They both have medium‐to‐large bivariate correlations with internalizing problems. Traditional victimization (sr = .22) and cyber‐victimization (sr = .12) were also uniquely related to internalizing problems. The difference in the relations between each type of victimization and internalizing problems was small (differential d = .06) and not statistically significant (p = .053). Moderation of these effect sizes by sample characteristics (e.g., age and proportion of girls) and study features (e.g., whether a definition of bullying was provided to participants and the time frame used as reference) was investigated. Results are discussed within the extant literature on cyber‐aggression and cyber‐victimization and future directions are proposed.