Constructing a Gene Team Tree in Almost O (n lg n) Time.

An important model of a conserved gene cluster is called the gene team model, in which a chromosome is defined to be a permutation of distinct genes and a gene team is defined to be a set of genes that appear in two or more species, with the distance between adjacent genes in the team for each chromosome always no more than a certain threshold δ. A gene team tree is a succinct way to represent all gene teams for every possible value of δ. The previous fastest algorithm for constructing a gene team tree of two chromosomes requires O(n lg n lglg n) time, which was given by Wang and Lin. Its bottleneck is a problem called the maximum-gap problem. In this paper, by presenting an improved algorithm for the maximum-gap problem, we reduce the upper bound of the gene team tree problem to O(n lg n α(n)). Since α grows extremely slowly, this result is almost as efficient as the current best upper bound, O(n lg n), for finding the gene teams of a fixed δ value. Our new algorithm is very efficient from both the theoretical and practical points of view. Wang and Lin's gene-team-tree algorithm can be extended to k chromosomes with complexity O(kn lg n lglg n). Similarly, our improved algorithm for the maximum-gap problem reduces this running time to O(kn lg n α(n)). In addition, it also provides new upper bounds for the gene team tree problem on general sequences, in which multiple copies of the same gene are allowed.

A new efficient algorithm for the gene-team problem on general sequences.

Identifying conserved gene clusters is an important step toward understanding the evolution of genomes and predicting the functions of genes. A famous model to capture the essential biological features of a conserved gene cluster is called the gene-team model. The problem of finding the gene teams of two general sequences is the focus of this paper. For this problem, He and Goldwasser had an efficient algorithm that requires O(mn) time using O(m + n) working space, where m and n are, respectively, the numbers of genes in the two given sequences. In this paper, a new efficient algorithm is presented. Assume m ≤ n. Let C = Σ(α)(∈)(Σ) o(1)(α)o(2)(α), where Σ is the set of distinct genes, and o(1)(α) and o(2)(α) are, respectively, the numbers of copies of α in the two given sequences. Our new algorithm requires O(min{C lg n, mn}) time using O(m + n) working space. As compared with He and Goldwasser's algorithm, our new algorithm is more practical, as C is likely to be much smaller than mn in practice. In addition, our new algorithm is output sensitive. Its running time is O(lg n) times the size of the output. Moreover, our new algorithm can be efficiently extended to find the gene teams of k general sequences in O(k C lg (n(1)n(2). . .n(k)) time, where n(i) is the number of genes in the ith input sequence.

Improved algorithms for finding gene teams and constructing gene team trees.

A gene team is a set of genes that appear in two or more species, possibly in a different order yet with the distance between adjacent genes in the team for each chromosome always no more than a certain threshold δ. A gene team tree is a succinct way to represent all gene teams for every possible value of δ. In this paper, improved algorithms are presented for the problem of finding the gene teams of two chromosomes and the problem of constructing a gene team tree of two chromosomes. For the problem of finding gene teams, Beal et al. had an O(n lg2 n)-time algorithm. Our improved algorithm requires O(n lg t) time, where t ≤ n is the number of gene teams. For the problem of constructing a gene team tree, Zhang and Leong had an O(n lg2 n)-time algorithm. Our improved algorithm requires O(n lg n lglg n) time. Similar to Beal et al.'s gene team algorithm and Zhang and Leong's gene team tree algorithm, our improved algorithms can be extended to k chromosomes with the time complexities increased only by a factor of k.

The effects of parental monitoring and leisure boredom on adolescents' Internet addiction.

This study explored the effects of parental monitoring, leisure boredom, and leisure activity on Internet addiction. The sample was 1,289 adolescents from eleven senior high schools in Taiwan. Participants were asked about their perception of being monitored by their parents, leisure boredom, leisure activities, and Internet addiction behavior. Results showed that leisure boredom and involvement in Internet and social activities increase the probability of Internet addiction; however, family and outdoor activities along with participative and supportive parental monitoring decrease these tendencies. Overall evidence suggests that parental monitoring is a major inhibitor of Internet addiction. Thus, adolescents should be supervised in their daily routines and encouraged to participate in family and outdoor activities. In addition, adolescents should develop a positive attitude toward leisure and the skills to prevent overdependence on online relationships with the assistance of parents. These findings suggest the preventive strategies regarding Internet addiction.

Impetus for worship: an exploratory study of adolescents' idol adoration behaviors.

The objective of this article is to explore the idolization behaviors of Taiwanese adolescents. The study gathered 1,636 questionnaires from 13 senior high schools across northern, central, southern, and eastern Taiwan. The results indicate that adolescents' gender correlates with the idol type they choose to adore when the idol is male. This study summarizes "exterior," "interior," "wealth," and "athlete" as four underlying idol traits attracting adolescents. Various types of idols are considered to be significantly different on these four traits. The impacts of the four traits on adolescents' worship levels are nonsymmetrical. While the traits of exterior and athlete are worship facilitators, the trait of wealth is a prohibitor. By contrast, the trait of interior is neutral and has no effect on worship levels. Furthermore, adolescents are involved in higher levels of worship when the idol is a media star or is the opposite gender of the adolescent. Generally, adolescents' worship levels are heightened by the illusion of a perfect idol, indicating nonrational worship behaviors. Implications regarding the association between adolescents' cognitive abilities and idols' traits are discussed for future research.

A comparison of major histocompatibility complex SNPs in Han Chinese residing in Taiwan and Caucasians.

Genetic dissection of complex diseases is both important and challenging. The human major histocompatibility complex is involved in many human diseases and genetic mechanisms. This highly polymorphic chromosome region has been extensively studied in Caucasians but not as well in Asians. Thus, we compared genotypic distributions, linkage disequilibria and haplotype blocks between Caucasian and Taiwan's Han Chinese populations. Moreover, we investigated the population admixture and phylogenetic system in Han Chinese residing in Taiwan. The results show that Taiwan's Han Chinese differ drastically in genotypic information compared with Caucasians but are relatively homogeneous among the three major ethnic subgroups, Minnan, Hakka and Mainlanders. Differences in allele frequency (AF) between Taiwanese and Caucasians in some disease-associated loci may reveal clues to differences in disease prevalence. The results of ethnic heterogeneity imply that public databases should be used with caution in cases where the study population(s) differs from the population characterized in the database. The high homogeneity we observed among the Taiwanese subpopulations mitigates the possibility of spurious association caused by ignoring population stratification in Taiwanese disease gene association studies. These results are useful for understanding our genetic background and designing future disease gene mapping studies.