Spatiotemporal variations of alpha and sigma band EEG in the waking-sleeping transition period

The aim of this study is to evaluate the spatiotemporal variation of alpha and sigma band EEGs during the waking-sleeping transition or hypnagogic period. Power and coherence from 7 EEG channels (Fp1, F7, Fz, C3, Pz, T5, O1) were studied using EEG records of the period of 5 min. before the onset of Stage 1 to 24 min. after the onset of Stage 1. The EEG spectra were computed for 4 frequency bands (alpha 1: 8.0-9.0 Hz, alpha 2: 9.5-11.0 Hz, alpha 3: 11.5-12.5 Hz, and sigma: 13.0-15.0 Hz). The power of alpha 1 and 2 bands initially started to decrease before the onset of Stage 1. Principal component analysis of the coherence yielded Generalized and Localized Components in each band. The Generalized Component was widespread across scalp areas, while the Localized Component was a restricted local area. The Generalized Components of alpha 1 and 2 bands reached stable levels of NREM sleep about 1 min. after the onset of Stage 1. The component of sigma band reached a stable level of NREM sleep about 0.6 min. before the onset of Stage 2, while the component of alpha 3 band reached a stable level of NREM sleep about 3.4 min. after the onset of Stage 2. These results suggest that the alpha-sigma band EEG structures during the waking-sleeping transition period may not be uniform across EEG bands and that the hypnagogic EEG changes may start before the onset of Stage 1 and continue for several minutes after the onset of Stage 2.     

The Effect of Auditory Cueing on the Spatial and Temporal Gait Coordination in Healthy Adults

Walk ratio, defined as step length divided by cadence, indicates the coordination of gait. During free walking, deviation from the preferential walk ratio may reveal abnormalities of walking patterns. The purpose of this study was to examine the impact of rhythmic auditory cueing (metronome) on the neuromotor control of gait at different walking speeds. Forty adults (mean age 26.6 ± 6.0 years) participated in the study. Gait characteristics were collected using a computerized walkway. In the preferred walking speed, there was no significant difference in walk ratio between uncued (walk ratio = .0064 ± .0007 m/steps/min) and metronome-cued walking (walk ratio = .0064 ± .0007 m/steps/min; p = .791). A higher value of walk ratio at the slower speed was observed with metronome-cued (walk ratio = .0071 ± .0008 m/steps/min) compared to uncued walking (walk ratio = .0068 ± .0007 m/steps/min; p < .001). The walk ratio was less at faster speed with metronome-cued (walk ratio = .0060 ± .0009 m/steps/min) compared to uncued walking (walk ratio = .0062 ± .0009 m/steps/min; p = .005). In healthy adults, the metronome cues may become an attentional demanding task, and thereby disrupt the spatial and temporal integration of gait at nonpreferred speeds.     

Walking patterns change rapidly following asymmetrical lower extremity loading

The purpose of this study was to determine the amount of time needed for individuals to become well accommodated to asymmetrical changes in lower extremity inertial properties. Participants walked at 1.57 m s(-1) during four separate data collection sessions over the period of eight days. On days 1 and 7, participants completed a 60 min treadmill protocol consisting of both overground (motion and ground reaction force recorded) and treadmill (vertical ground reaction force recorded) walking. On day 1, 1.95 kg was attached distally to one shank prior to the start of the 60 min treadmill protocol and was not removed until day 7. On day 7, the load was permanently removed prior to the 60 min treadmill protocol. On days 2 and 8 participants completed three overground walking trials and walked on the treadmill for approximately 5 min. Stance and swing time asymmetries appeared immediately and were complete following initial assessment after the load was attached. Net joint moments at the knee and hip were altered and continued to change beyond initial exposure to the load, but these changes were complete within 5 min. Overall, results suggest that changes in walking symmetry due to asymmetrical lower extremity loading are immediate and complete within 5 min of exposure to the load. We recommend that at least 5 min of walking or other normal activity be used to accommodate individuals to novel asymmetrical lower extremity loading.     

Optimization characteristics of walking with and without a load on the trunk of the body

Previous work showed that subjects naturally adopt a walking speed which optimizes energy cost of locomotion and stability of stride; however, no studies have examined whether these criteria are affected by carrying an external load. The purpose of this study was to compare optimization characteristics during loaded or unloaded walking. Energy cost and stride characteristics were measured for 10 subjects with and without a load on the trunk of the body of 10% of the body weight during 4 sessions. The first 2 sessions represent free walking at 2.5, 3, 3.5, 4, 4.5, and 5 km x hr.(-1). The last sessions represent free vs forced walking at constant speed (preferred frequency and +/- 10 PF and +/-20% of preferred frequency). Results show an effect of load on energy cost of walking but no effect on the optimal speed for stability. Furthermore, when carrying a load the subject does not adopt systematically the speed that minimizes physiological cost. Our findings suggest the necessity to consider this effect to prevent gait disturbance and maintain the health benefits of walking.     

Modification of EEG power spectra and EEG connectivity in autobiographical memory: a sLORETA study

The aim of the present study was to explore the modifications of scalp EEG power spectra and EEG connectivity during the autobiographical memory test (AM-T) and during the retrieval of an autobiographical event (the high school final examination, Task 2). Seventeen healthy volunteers were enrolled (9 women and 8 men, mean age 23.4 ± 2.8 years, range 19–30). EEG was recorded at baseline and while performing the autobiographical memory (AM) tasks, by means of 19 surface electrodes and a nasopharyngeal electrode. EEG analysis was conducted by means of the standardized LOw Resolution Electric Tomography (sLORETA) software. Power spectra and lagged EEG coherence were compared between EEG acquired during the memory tasks and baseline recording. The frequency bands considered were as follows: delta (0.5–4 Hz); theta (4.5–7.5 Hz); alpha (8–12.5 Hz); beta1 (13–17.5 Hz); beta2 (18–30 Hz); gamma (30.5–60 Hz). During AM-T, we observed a significant delta power increase in left frontal and midline cortices (T = 3.554; p < 0.05) and increased EEG connectivity in delta band in prefrontal, temporal, parietal, and occipital areas, and for gamma bands in the left temporo-parietal regions (T = 4.154; p < 0.05). In Task 2, we measured an increased power in the gamma band located in the left posterior midline areas (T = 3.960; p < 0.05) and a significant increase in delta band connectivity in the prefrontal, temporal, parietal, and occipital areas, and in the gamma band involving right temporo-parietal areas (T = 4.579; p < 0.05). These results indicate that AM retrieval engages in a complex network which is mediated by both low- (delta) and high-frequency (gamma) EEG bands.     

Peer violence in the School Environment and Its Relationship with Subjective Well-Being and Perceived Social Support Among Children and Adolescents in Northeastern Brazil

The general aim of this study was to analyse the relationship between peer violence in the school environment (bullying), subjective well-being and perceived social support from the perspective of 910 children and adolescents in Years 6 and 7 of primary school (M = 11.90 years old; SD = 1.21). The participants were taken from 27 primary schools—both state-run and private, urban and rural—in Cearà state (Brazil). The following instruments were used: the Peer Victimization and Aggression Scale (EVAP); the Social Support from Family and Friends Scale (SSA); an index of satisfaction with different developmental contexts (home, school, neighbourhood); and as indicators of subjective well-being, three scales (Single item on Overall Life Satisfaction, Personal Well-Being Index School Children, Students’ Life Satisfaction Scale). Results indicated that aggression and victimization behaviours correlated negatively with the three well-being indicators used, while social support and satisfaction with different developmental contexts correlated positively. When considering type of involvement in bullying, victims, perpetrators and perpetrator–victims all scored lower on subjective well-being than those not involved in bullying. A model is also presented that explains 42 % of well-being. Understanding how bullying relates to well-being and how social support and favourable developmental contexts can act as protective factors are particularly important when designing public policies aimed at intervening in violence prevention and promoting well-being in childhood and adolescence.     

Regulation of exercise intensity using ratings of perceived exertion during passive visual distraction

The purpose of this investigation was to determine if passive visual distraction altered ability to regulate exercise intensity as, assessed by ratings of perceived exertion during a 30-min. treadmill run. 10 trained females (VO2max, 52.7 ml.kg-1.min.-1) performed a graded exercise test on a treadmill to assess maximal aerobic power and rating of perceived exertion, oxygen uptake (VO2), heart rate, and running velocity at the 2.5 mmol.L-1 blood lactate concentration. Subjects then used the target rating of perceived exertion to regulate exercise intensity during a control condition, and two treatment runs with passive visual distractions. During the treatment sessions, the subjects ran on a treadmill while viewing a high-action or a low-action video with no audio. The subjects were allowed to adjust the treadmill speed throughout the run to maintain the target rating of perceived exertion; however, subjects were not allowed to view the speed setting. There were no significant differences in blood lactate concentration among the conditions for the control, low action, high action, or graded exercise test (p < or = .05). No significant differences in VO2 or running velocity were found within or among the 30-min. treatment runs and the graded exercise test. Heart rate at 5 min. of exercise during control (158 +/- 3 b.min.-1), low action (158 +/- 3 b.min.-1), and high action (159 +/- 2 b.min.-1) was significantly lower than the graded exercise test (169 +/- 3 b.min.-1). Based on the data collected, visual passive distraction did not alter regulation of intensity using ratings of perceived exertion during a 30-min. treadmill run.     

Cadence (steps/min) as an indicator of the walk-to-run transition

BackgroundHumans naturally transition from walking to running at a point known as the walk-to-run transition (WRT). The WRT commonly occurs at a speed of ∼2.1 m/s (m/s) or a Froude number (dimensionless value considering leg length) of 0.5. Emerging evidence suggests the WRT can also be classified using a cadence of 140 steps/min. An accurate cadence-based WRT metric would aid in classifying wearable technology minute-level step metrics as walking vs. running.PurposeTo evaluate performance of 1) WRT predictors directly identified from a treadmill-based dataset of sequentially faster bouts, and 2) accepted WRT predictors compiled from previous literature.MethodsTwenty-eight adults (71.4% men; age = 36.6 ± 12.8 years, BMI = 26.2 ± 4.7 kg/m²) completed a series of five-minute treadmill walking bouts increasing in 0.2 m/s increments until they freely chose to run. Optimal WRT values for speed, Froude number, and cadence were identified using receiver operating characteristic (ROC) curve analyses. WRT value performance was evaluated via classification accuracy metrics.ResultsOverall accuracies (metric, percent) according to WRT predictors from previous literature were: speed (2.1 m/s, 55.0%), Froude number (0.5, 76.8%), and cadence (140 steps/min, 91.1%), and those from the dataset herein were: speed (1.9 and 2.0 m/s, 78.6%), Froude number (0.68, 77.3%), and cadence (134, 139, and 141 steps/min, 92.9%). The three equally accurate cadence values support a heuristic range of cadence-based WRT values in young and middle-aged adults: 135–140 steps/min.SignificanceA tight range of cadence values performed better as WRT predictors compared to either previously reported or directly identified speed or Froude number values. These findings have important implications for gait classification, especially considering cadence is a simple metric which can be readily assessed across settings using direct observation or wearable technologies.     

Reliability and validity of the tritrac-R3D accelerometer during backpacking: a case study.

This study investigated the utility of the Tritrac-R3D accelerometer as a reliable and valid instrument in the quantification of physical activity while backpacking in the field and to evaluate heart-rate responses and oxygen consumption to assess the feasibility of using the Tritrac-R3D to estimate caloric expenditure. Two 7-day backpacking expeditions were conducted in two consecutive years by a single subject at Grand Canyon National Park, Arizona. The average hiking heart rate ranged front 60% to 77% HRmax during the expeditions. The average rate of estimated caloric cost ranged from 6.8 to 11.7 kcals x min.(-1) (equivalent to 408 to 702 kcals x hr.(-1)), indicating a relatively moderate to high level of exertion. The Tritrac had adequate consistency and reliability in the field between the two expeditions in recorded activity counts. The Tritrac underestimated caloric expenditure during backpacking with changes in terrain, and hiking speed contributed to even greater disparity in accuracy.     

Lateral dominance of legs in maximal muscle power, muscular endurance, and grading ability.

The purpose of this study was to examine lateral dominance in maximal muscle power, muscular endurance, and grading ability, using isokinetic mulscular strength in knee extension and flexion. The subjects were 50 healthy male students whose ages ranged from 19 to 23 years (M height: 173.6+/-6.2 cm, M weight: 67.2+/-6.8 kg). Their dominant legs for power exertion and for functional use were based on questionnaire items selected from those used in previous studies. The angular velocities of extension and flexion for exerting maximal muscle power were 60, 180, and 300 x sec.(-1). A continuous exertion 30 times at an angular velocity of 180 sec.(-1) was used as the load for muscular endurance. For grading ability, 25%, 50% and 75% of the maximal muscle strength at angular velocities of 60 and 180 x sec.(-1) were the required values, and the difference between these values and the exerted muscular strength was evaluated. The dominant leg and nondominant leg were compared for both power exertion and functional use. There was no lateral dominance in maximal muscle power and muscular endurance. In muscular endurance, especially, some subjects showed one leg superior in power exertion and some superior in functional use. Lateral dominance was noted across maximal muscle power and muscular endurance in grading ability. The dominant leg tended to be better than the nondominant leg in functional use. However, lateral dominance was not remarkable for flexing motion and in exertion for a short time.     

Psychometric assessment of the processes of change scale for sun protection

The fourteen-factor Processes of Change Scale for Sun Protection assesses behavioral and experiential strategies that underlie the process of sun protection acquisition and maintenance. Variations of this measure have been used effectively in several randomized sun protection trials, both for evaluation and as a basis for intervention. However, there are no published studies, to date, that evaluate the psychometric properties of the scale. The present study evaluated factorial invariance and scale reliability in a national sample (N = 1360) of adults involved in a Transtheoretical model tailored intervention for exercise and sun protection, at baseline. Invariance testing ranged from least to most restrictive: Configural Invariance (constraints only factor structure and zero loadings); Pattern Identity Invariance (equal factor loadings across target groups); and Strong Factorial Invariance (equal factor loadings and measurement errors). Multi-sample structural equation modeling tested the invariance of the measurement model across seven subgroups: age, education, ethnicity, gender, race, skin tone, and Stage of Change for Sun Protection. Strong factorial invariance was found across all subgroups. Internal consistency coefficient Alpha and factor rho reliability, respectively, were .83 and .80 for behavioral processes, .91 and .89 for experiential processes, and .93 and .91 for the global scale. These results provide strong empirical evidence that the scale is consistent, has internal validity and can be used in research interventions with population-based adult samples.     

Effects of Backpack Carriage on Dual-Task Performance in Children During Standing and Walking

Primary school children perform parts of their everyday activities while carrying school supplies and being involved in attention-demanding situations. Twenty-eight children (8–10 years old) performed a 1-legged stance and a 10 m walking test under single- and dual-task situations in unloaded (i.e., no backpack) and loaded conditions (i.e., backpack with 20% of body mass). Results showed that load carriage did not significantly influence children's standing and walking performance (all p > .05), while divided attention affected all proxies of walking (all p < .001). Last, no significant load by attention interactions was detected. The single application of attentional but not load demand negatively affects children's walking performance. A combined application of both did not further deteriorate their gait behavior.     

Evidence of improved shooting precision in biathlon after 10 weeks of combined relaxation and specific shooting training

The aim of this study was to test the hypothesis that a combined relaxation (applied tension release, ATR) and specific shooting training regimen may enhance shooting ability of biathlon athletes. Seven biathletes of high national level were randomized into an experimental group (age 20 ± 5 years; Vo2max 60 ± 8 mL kg(-1) min(-1)) and were asked to add this special training intervention to their regular training for 10 weeks, while five other biathletes served as controls (age 19 ± 2 years; Vo2max 57 ± 10 mL kg(-1) min(-1)). The shooting ability of the subjects was assessed before and after the intervention at rest and after roller skiing on a treadmill in a laboratory-based competition simulating assessment. After the intervention period, the experimental group demonstrated a significantly enhanced shooting performance compared to the control group. No changes in Vo2max or in heart rate and Vo2 responses were observed before and after the intervention in either group and there were no differences between the groups in these parameters. Thus, the preliminary conclusion is that a combination of ATR and specific shooting training seems to be instrumental in enhancing the shooting performance in biathlon.     

青少年元认知、大五人格与学习适应行为的关系

研究试图探讨青少年学习适应行为的认知机制以及大五人格特质在其中所起的作用.采用青少年社会适应行为量表、大五人格简式量表及元认知问卷对广州市985名中学生进行测试.结果表明:(1)学校、年级因素在元认知总分、学习适应行为上均存在显著差异;(2)学习适应行为与元认知、大五人格各维度均存在显著相关;(3)大五人格各特质在元认知与学习适应行为的关系间起到中介作用.     

Child Conduct Problems Across Home and School Contexts: a Person-Centered Approach

To examine patterns of conduct problems across the home and school context, we used latent class analysis to analyze primary caregivers’ and teachers’ ratings on the conduct problems subscale of the Strengths and Difficulties Questionnaire (Goodman Journal of Child Psychology and Psychiatry, 38, 581–586, 1997) in the Family Life Project (N?=?1,292), a prospective study of child development in rural and small town contexts. We found a similar four-class solution at 5 and 7 years of age. In decreasing prevalence, the following classes were identified: (1) low symptoms reported by both informants (low cross-context); (2) high parent-reported symptoms, low teacher-reported symptoms (home context); (3) low parent-reported symptoms, moderate teacher-reported symptoms (school context); and (4) high symptoms reported by both informants (high cross-context). Classes exhibited stability from age five to age seven: children were more likely to remain in the same class than to transition to a different class, and longitudinal stability was especially high for children in the low cross-context class at age 5. A number of child and family characteristics measured in early childhood (executive function, verbal ability, poverty-related risk, sensitive parenting, and parental depressive symptoms) were associated with class membership at age five and age seven, but were generally not associated with longitudinal transitions between classes.     

图式教学对阅读理解能力、推理能力与自我效能感的影响

本研究采用自然实验法对吉林省松原市逸夫实验小学160名四、五年级的学生进行了对比实验研究,探讨图式教学对阅读理解能力、推理能力和自我效能感的影响。结果表明:(1)四、五年级实验班学生的阅读理解能力普遍提高,五年级明显。(2)仅五年级实验班学生的推理能力有了显著提高,相对而言,图式教学对五年级学生推理能力的影响要优于四年级。(3)四、五年级实验班学生的自我效能感均明显增强。这说明图式教学比常规教学更能有效地提高学生的阅读理解能力和自我效能感。     

青少年学生的自立人格

经过5个步骤编制出了人格特质词的《大学生问卷》、《高中生问卷》、《初中生问卷》和《青少年学生问卷》,分别对大学生、高中生和初中生进行调查和探索性因素分析。结果发现：①《大学生问卷》显示的自立人格包括主动性、开放性、人际责任、积极性和独立性五个维度;②《高中生问卷》显示的自立人格包括人际开放与责任性、灵活与独立性、主动性和行为责任四个维度;③《初中生问卷》显示的自立人格包括主动与行为责任、开放性、人际责任、积极性、灵活与独立性五个维度;④《青少年学生问卷》显示的自立人格包括灵活与独立性、责任性、主动性、人际开放四个维度。最后,对自立人格构念的合理性、自立人格中“开放性”与“责任性”维度的特点、青少年学生自立人格结构的一致性程度以及本研究在探索自立人格结构方面的优劣等问题进行了讨论     

Can the Transition To and From Running and the Metabolic Cost of Running Be Determined From the Kinetic Energy of Running?

An experiment was conducted in which volume of used oxygen per stride time and the total segmental changes in kinetic energy generated per stride time, &grD;E(k)>s(-1), of 11 participants were determined on Day 1 for 7 treadmill running speeds. Gait transition speeds were determined on Day 2. Running metabolism and transition speed were predicted from the Day 1 mechanics of running expressed in Speed x &grD;E(k)>s(-1) coordinates. Predictions followed from the relation between 2 generalized quality ratios Q(metab), and Q(mech), with numerator &grD;E(k)>s(-1). In Q(metab), the denominator was the volume of used oxygen per stride time; in Q(mech), the denominator was the absolute regression constant from the linear dependency of &grD;E(k)>s(-1) on speed.     

Masculinity and Femininity: A Bipolar Construct and Independent Constructs

ABSTRACT The present investigation is a reanalysis of data from Antill and Cunningham (1979, 1980, Marsh, Antill, & Cunningham, 1987) consisting of responses to five masculinity-femininity (MF) instruments, two self-esteem instruments, and two social desirability scales Correlations between M and F for the five instruments varied from 23 to approximately - 10, support for distinguishable (nonbipolar) M and F factors was found for four of the instruments Applying confirmatory factor analysis (CFA) and hierarchical CFA (HCFA), the present study examined the dimensionality of MF and the influence of method/ halo effects m response to specific instruments The best fitting model identified three higher order factors, in support of traditional personality theories one factor was a bipolar MF construct, but m support of androgyny theory the other two factors were distinguishable M and F factors The factor structures were reasonably invanant for men and women, and methodological implications of this important finding were examined In subsequent analyses, the higher order MF factors were related to self-esteem, social desirability, and gender in order to further test interpretations of the MF factors.