The rainbow vertex-index of complementary graphs

A vertex-colored graph $G$ is \emph{rainbow vertex-connected} if two vertices are connected by a path whose internal vertices have distinct colors. The \emph{rainbow vertex-connection number} of a connected graph $G$, denoted by $rvc(G)$, is the smallest number of colors that are needed in order to make $G$ rainbow vertex-connected. If for every pair $u,v$ of distinct vertices, $G$ contains a vertex-rainbow $u-v$ geodesic, then $G$ is \emph{strongly rainbow vertex-connected}. The minimum $k$ for which there exists a $k$-coloring of $G$ that results in a strongly rainbow-vertex-connected graph is called the \emph{strong rainbow vertex number} $srvc(G)$ of $G$. Thus $rvc(G)\leq srvc(G)$ for every nontrivial connected graph $G$. A tree $T$ in $G$ is called a \emph{rainbow vertex tree} if the internal vertices of $T$ receive different colors. For a graph $G=(V,E)$ and a set $S\subseteq V$ of at least two vertices, \emph{an $S$-Steiner tree} or \emph{a Steiner tree connecting $S$} (or simply, \emph{an $S$-tree}) is a such subgraph $T=(V',E')$ of $G$ that is a tree with $S\subseteq V'$. For $S\subseteq V(G)$ and $|S|\geq 2$, an $S$-Steiner tree $T$ is said to be a \emph{rainbow vertex $S$-tree} if the internal vertices of $T$ receive distinct colors. The minimum number of colors that are needed in a vertex-coloring of $G$ such that there is a rainbow vertex $S$-tree for every $k$-set $S$ of $V(G)$ is called the {\it $k$-rainbow vertex-index} of $G$, denoted by $rvx_k(G)$. In this paper, we first investigate the strong rainbow vertex-connection of complementary graphs. The $k$-rainbow vertex-index of complementary graphs are also studied

Dynamic Change of Amplitude for OCT Functional Imaging

Optical coherence tomography (OCT) is capable of non-destructively obtaining cross-sectional information of samples with micrometer spatial resolution, which plays an important role in ophthalmology and endovascular medicine. Measuring OCT amplitude can obtain three-dimensional structural information of the sample, such as the layered structure of the retina, but is of limited use for functional information such as tissue specificity, blood flow, and mechanical properties. OCT functional imaging techniques based on other optical field properties including phase, polarization state, and wavelength have emerged, such as Doppler OCT, optical coherence elastography, polarization-sensitive OCT, and visible-light OCT. Among them, functional imaging techniques based on dynamic changes of amplitude have significant robustness and complexity advantages, and achieved significant clinical success in label-free blood flow imaging. In addition, dynamic light scattering OCT for 3D blood flow velocity measurement, dynamic OCT with the ability to display label-free tissue/cell specificity, and OCT thermometry for monitoring the temperature field of thermophysical treatments are the frontiers in OCT functional imaging. In this paper, the principles and applications of the above technologies are summarized, the remaining technical challenges are analyzed, and the future development is envisioned.Comment: 25 pages, in Chinese language, 9 figure

Parental Psychological Control and Adolescent Aggressive Behavior: Deviant Peer Affiliation as a Mediator and School Connectedness as a Moderator

Abundant evidence has demonstrated an association between parental psychological control and adolescent aggressive behavior. However, the mediating and moderating mechanisms underlying this relation are still under-investigated. Grounded in the social development model and stress-buffering model, this study investigated whether deviant peer affiliation mediates the relation between parental psychological control and adolescent aggressive behavior, and whether this indirect link is moderated by school connectedness. A total of 4265 adolescents (Meanage = 13.66 years, SD = 2.74, 48.63% male) from southern China completed questionnaires regarding parental psychological control, deviant peer affiliation, school connectedness, and aggressive behavior. Structural equation models revealed that the relation between parental psychological control and aggressive behavior is partially mediated by deviant peer affiliation. Moreover, this indirect link was stronger for adolescents with low levels of school connectedness than for those with high levels of school connectedness. This study thus identifies the potential underlying mechanism by which parental psychological control is associated with adolescent aggressive behaviors, which has important implications for theory and prevention

School Climate, Loneliness, and Problematic Online Game Use Among Chinese Adolescents: The Moderating Effect of Intentional Self-Regulation

Evidently, the school climate is important in reducing adolescent problematic online game use (POGU); however, the mechanism accounting for this association remains largely unknown. This study examined whether loneliness mediated the link between school climate and adolescent POGU and whether this mediating process was moderated by adolescent intentional self-regulation. To this end, self-report questionnaires were distributed. Participants were 500 12–17-years-old Chinese adolescents (Meanage = 13.59 years, 50.60% male). After controlling for adolescents' gender, age, family socioeconomic status, and self-esteem, the results showed that the negative association between school climate and adolescent POGU was partially mediated by loneliness. Moreover, this indirect link was stronger for adolescents with low intentional self-regulation than for those with high intentional self-regulation. These findings highlight loneliness as a potential mechanism linking school climate to adolescent POGU and provide guidance for the development of effective interventions for addressing the adverse effects of a negative school climate

Sensation Seeking, Deviant Peer Affiliation, and Internet Gaming Addiction Among Chinese Adolescents: The Moderating Effect of Parental Knowledge

Although there is abundant evidence that an association between sensation seeking and adolescent Internet gaming addiction (IGA) exists, research has provided little insight into why adolescents with high sensation seeking are more likely to be focused on Internet and video games. Grounded in the social development model and ecological systems theory, this study investigated whether deviant peer affiliation mediated the relationship between sensation seeking and adolescent IGA, and whether this indirect link was moderated by parental knowledge. Participants were 1293 Chinese adolescents (49.65% male, Mage = 12.89 ± 0.52 years) who completed questionnaires assessing sensation seeking, deviant peer affiliation, parental knowledge, and IGA. Structural equation models revealed that the positive association between sensation seeking and adolescent IGA was partially mediated by deviant peer affiliation. In addition, this indirect link was significantly moderated by parental knowledge. Specifically, the indirect path from sensation seeking to adolescent IGA was stronger for adolescents with low parental knowledge than for those with high parental knowledge. Identifying the role of peers and parents in the onset of adolescent IGA has key implications for prevention and intervention

Peer Victimization and Aggressive Behavior Among Chinese Adolescents: Delinquent Peer Affiliation as a Mediator and Parental Knowledge as a Moderator

Grounded in social network theory and a risk-buffering model, this study examined whether delinquent peer affiliation mediated the association between peer victimization and adolescent aggressive behavior and whether this mediating process was moderated by parental knowledge. A total of 4,209 Chinese adolescents (48.47% male, Mage = 13.68) completed questionnaires on peer victimization, parental knowledge, delinquent peer affiliation, and adolescent aggressive behavior. Path analyses showed that delinquent peer affiliation partially mediated the relationship between peer victimization and aggressive behavior. Moreover, parental knowledge had a protective effect of buffering the adverse influence of peer victimization on aggressive behavior. This indirect link was stronger for adolescents with low parental knowledge than for those with high parental knowledge. This finding highlights delinquent peer affiliation as a potential link between peer victimization and aggressive behavior and provides an effective intervention for addressing the adverse effects of peer victimization