Mediation and Moderation: Testing Relationships Between Symptom Status,Functional Health,and Quality of Life in HIV Patients

Three demographic dimensions previously isolated by cluster analysis procedures (using BC TRY System computer analyses) were compared in different metropolitan areas for their stability over time and place. Also, the social areas discovered within the communities were studied for their stability over time and place. The three demographic dimensions (socio-economic independence, family life, and assimilation) accounted for the generality of 33 census tract (1940) characteristics in two communities. It was also shown that the three basic dimensions were essentially unchanged during the decade which included World War 11. The stability of these dimensions was retained even though there was considerable change in residents in each metropolitan area during the decade. The validity of cluster-search procedures is demonstrated by the stability of the three demographic dimensions.     

Gamers just want to have fun? Toward an understanding of the online game acceptance

This study sought to examine the factors affecting the acceptance of an entertainment medium, particularly online games, by expanding the technology acceptance model. To measure factors affecting the acceptance of online games, we fielded a survey with 244 gamers serving as respondents. Perceived usefulness, enjoyment, and economic value were found to have a positive influence on attitude toward gaming, whereas perceived ease of use was not a significant predictor. In addition, we found that gender and game type (multiplayer or not) showed differing patterns of results. Interestingly, perceptions of mass acceptance of gaming were found to have a negative effect on attitude toward online games. Theoretical and practical implications of these findings are discussed.     

The control of posture in newly standing infants is task dependent

The postural sway patterns of newly standing infants were compared under two conditions: standing while holding a toy and standing while not holding a toy. Infants exhibited a lower magnitude of postural sway and more complex sway patterns when holding the toy. These changes suggest that infants adapt postural sway in a manner that facilitates visually fixating on and stabilizing the toy in their hand. When simply standing, infants exhibited postural sway patterns that appeared to be more exploratory in nature. Exploratory sway patterns may allow infants to learn the affordances of their new standing posture. These results demonstrate that newly standing infants are capable of task-dependent postural control.     

Responses toward a trapped animal by wild bonobos at Wamba

Chimpanzees and bonobos are the closest living relatives of humans and diverged relatively recently in their phylogenetic history. However, a number of reports have suggested behavioral discrepancies between the two Pan species, such as more cooperative and tolerant social interaction and poorer tool-using repertoires in bonobos. Concerning hunting behavior and meat consumption, recent studies from the field have confirmed both behaviors not only in chimpanzees but also in bonobos. The present study reports an encounter by wild bonobos at Wamba with a duiker trapped in a snare. Bonobos interacted with the live duiker for about 10 min but did not eventually kill the animal. They showed fear responses when the duiker moved and exhibited behaviors related to anxiety and stress such as branch-drag displays and self-scratching. Although bonobos manipulated nearby saplings and parts of the snare, they did not use detached objects to make indirect contact with the duiker. Juveniles and adults of both sexes engaged in active interactions with the trapped duiker. Overall, bonobos’ behavioral responses indicated species-specific cognitive characteristics largely different from those of chimpanzees.     

Factorial invariance in multilevel confirmatory factor analysis

This paper presents a procedure to test factorial invariance in multilevel confirmatory factor analysis. When the group membership is at level 2, multilevel factorial invariance can be tested by a simple extension of the standard procedure. However level‐1 group membership raises problems which cannot be appropriately handled by the standard procedure, because the dependency between members of different level‐1 groups is not appropriately taken into account. The procedure presented in this article provides a solution to this problem. This paper also shows Muthén's maximum likelihood (MUML) estimation for testing multilevel factorial invariance across level‐1 groups as a viable alternative to maximum likelihood estimation. Testing multilevel factorial invariance across level‐2 groups and testing multilevel factorial invariance across level‐1 groups are illustrated using empirical examples. SAS macro and Mplus syntax are provided.     

Comparative analyses of rider position according to skill levels during walk and trot in Jeju horse

The purpose of this study was to evaluate the rider position at walk and trot as a function of rider skill level by analyzing joint angles. Participants included three advanced riders and six beginners, and training was conducted for one hour, twice a week for 24 weeks. In the walk stage of the beginners’ group, the elbows and shoulders sustained postures comparable to those of the advanced riders group; the trunk tilted forwards at first, but later it tilted slightly behind the vertical. The knee, ankle, and left–right angle kept stable postures after 12 weeks of training (p < .05). The front-rear (FR) angle of the beginners group improved during training, but it was still lower than the advanced riders group after 24 weeks of training (p < .05). At trot, while the knee angle measurement of the beginners’ group was similar to the advanced riders, the ankle joint sustained a forward point posture. The ankle joint maintained dorsiflexion posture with 83.9° ± 5.3 in the advanced riders group, while the beginners group had plantar flexion posture with 98.7° ± 6.0. This study suggested that the correlation between the joint and body segment angles could be an important indicator in the evaluation of rider proficiency.     

Effects of skewness and kurtosis on normal-theory based maximum likelihood test statistic in multilevel structural equation modeling

A simulation study investigated the effects of skewness and kurtosis on level-specific maximum likelihood (ML) test statistics based on normal theory in multilevel structural equation models. The levels of skewness and kurtosis at each level were manipulated in multilevel data, and the effects of skewness and kurtosis on level-specific ML test statistics were examined. When the assumption of multivariate normality was violated, the level-specific ML test statistics were inflated, resulting in Type I error rates that were higher than the nominal level for the correctly specified model. Q-Q plots of the test statistics against a theoretical chi-square distribution showed that skewness led to a thicker upper tail and kurtosis led to a longer upper tail of the observed distribution of the level-specific ML test statistic for the correctly specified model.     

Differences in attentional involvement underlying the perception of distinctive and typical faces

Differences in human faces can be evaluated along a continuum that ranges from 'distinctive' to 'typical.' We examined processing differences between distinctive and typical faces by two attentional tasks that induce attentional blink (AB). Given that AB is believed to reflect temporal or capacity limits of attention, stimuli that survive AB are believed to be associated with greater processing efficiency. In a change-detection task, participants were required to detect changes in the two pairs of faces that were presented in rapid succession. Changes involving the distinctive face of a pair were more likely to be detected than those involving a typical face. In a face-identification task, distinctive faces embedded in a rapid serial visual presentation (RSVP) stream were identified with a greater accuracy than typical faces. Together, our results suggest that distinctive faces are associated with greater processing efficiency and may be explained in terms of perceptual salience, a stimulus dimension known to attract attention.     

Learning and transfer of a relative phase pattern and a joint amplitude ratio in a rhythmic multijoint arm movement

According to the coordination dynamics perspective, one can characterize the learning of novel relative phase patterns as the formation of a stable attractor in the coordination landscape of the order parameter relative phase. The authors examined 18 participants' learning and transfer of a 90 degrees relative phase pattern and a 0.6-joint-amplitude ratio between the elbow and wrist. Variability in the relative phasing and the joint amplitude ratio between the elbow and wrist decreased with practice. Positive transfer of the 90 degrees relative phase pattern was not dependent on the learning arm (dominant or nondominant). Positive transfer of the joint amplitude ratio was dependent on the learning arm and the direction of transfer. The results demonstrated that relative phase is an order parameter that characterizes the coordination dynamics of learning and transferring multijoint arm movements, and they provide preliminary evidence that joint amplitude ratios act as order parameters in the learning and transfer of multijoint arm movements.     

Identification with television newscasters and Korean college students' voting intentions and political activities

In 2004, many prominent newscasters ran as candidates in the Korean general election and won. The present study examines whether young voters' identification with newscasters was significantly associated with Korean voting behaviour as well as with other forms of political participation. Analysis of 270 respondents showed that identification with newscasters contributed significantly to young Koreans' intentions to vote for newscasters and to their active involvement in other forms of campaign participation, beyond the effects of age, gender, and level of political interest. Additionally, news media exposure, perception of newscaster behaviours, emotional involvement, surveillance motivation and entertainment motivation were all positively related to voters' identification with newscasters.