BACKGROUND: Long screen time hours may be associated with behavioral problems in children. To better understand the relationship between children's behavioral problems and screen time, it the associated risk factors must be subdivided based on the purpose underlying screen use. This study examined the relationship between screen time based on intended usage and behavioral problems in Japan. METHODS: This study included 3,332 children aged between 7-17 years from the Hokkaido Study on Environment and Children's Health. From October 2020 to October 2021, the children and their parents answered questionnaires on the children's screen use duration (never used, <30 min, ≥30 min & <1 hour, ≥1 h & <2 h, ≥2 h) based on seven intended usage categories: watching television/video, video gaming, reading books/comics, sending/receiving e-mail/messages, browsing/posting on social networking services, studying for classes/homework, drawing/editing pictures/photos/videos, along with the Strengths and Difficulties Questionnaire (SDQ). Logistic regression was used to analyze the association between screen time, purpose of children's screen use, and behavioral problems across the 13 SDQ total scores. RESULTS: The mean ± standard deviation age of the participants was 12.4 ± 2.4-years-old, 487 (14.6%) children were determined to have behavioral problems, and the duration of screen time increased with their age. The children's primary purposes for screen use were watching television/video, video gaming, sending/receiving e-mail/messages, and browsing/posting on social networking services. Children who reported playing video games for ≥2 hours on weekdays had higher odds of problematic total difficulties scores than never user (Odds Ratio: 2.10, 95% confidence interval: 1.45-3.06). CONCLUSION Long video gaming screen time is associated with behavioral issues, hyperactivity/inattention, and prosocial behaviors in children. Conversely, watching television and videos for 30 min-1 h per day, using e-mail or messaging, and using social networking services were significantly association with reduced odds ratio for peer relationship problems as compared to children who never engaged in these activities. Longitudinal follow-up is needed to further examine screen time and problem behaviors.
Humans ; Screen Time ; Child ; Japan/epidemiology* ; Male ; Female ; Adolescent ; Problem Behavior/psychology* ; Surveys and Questionnaires ; Child Behavior ; Television/statistics & numerical data* ; Video Games/statistics & numerical data*

Graphical representation of DNA sequences is one of the most popular techniques for alignment-free sequence comparison. Here, we propose a new method for the feature extraction of DNA sequences represented by binary images, by estimating the similarity between DNA sequences using the frequency histograms of local bitmap patterns of images. Our method shows linear time complexity for the length of DNA sequences, which is practical even when long sequences, such as whole genome sequences, are compared. We tested five distance measures for the estimation of sequence similarities, and found that the histogram intersection and Manhattan distance are the most appropriate ones for phylogenetic analyses.

We explored the possibilities of whole-genome duplication (WGD) in prokaryotic species,where we performed statistical analyses of the configurations of the central angles between homologous tandem repeats (TRs) on the circular chromosomes.At first,we detected TRs on their chromosomes and identified equivalent tandem repeat pairs (ETRPs); here,an ETRP is defined as a pair of tandem repeats sequentially similar to each other.Then we carried out statistical analyses of the central angle distributions of the detected ETRPs on each circular chromosome by way of comparisons between the detected distributions and those generated by null models.In the analyses,we estimated a P value by a simulation using the Kullback-Leibler divergence as a distance measure between two distributions.As a result,the central angle distributions for 8 out of the 203 prokaryotic species showed statistically significant deviations (P<0.05).In particular,we found out the characteristic feature of one round of WGD in Photorhabdus luminescens genome and that of two rounds of WGD in Escherichia coli K12.