다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Random graphs

Statistical physics has proven to be a fruitful framework to describe phenomena outside the realm of traditional physics. Recent years have witnessed an attempt by physicists to study collective phenomena emerging from the interactions of individuals as elementary units in social structures. A wide list of topics are reviewed ranging from opinion and cultural and language dynamics to crowd behavior, hierarchy formation, human dynamics, and social spreading. The connections between these problems and other, more traditional, topics of statistical physics are highlighted. Comparison of model results with empirical data from social systems are also emphasized.

Statistical physics of social dynamics

Social Network Analysis

We explore the coupled dynamics of the internal states of a set of interacting elements and the network of interactions among them. Interactions are modeled by a spatial game and the network of interaction links evolves adapting to the outcome of the game. As an example, we consider a model of cooperation in which the adaptation is shown to facilitate the formation of a hierarchical interaction network that sustains a highly cooperative stationary state. The resulting network has the characteristics of a small world network when a mechanism of local neighbor selection is introduced in the adaptive network dynamics. The highly connected nodes in the hierarchical structure of the network play a leading role in the stability of the network. Perturbations acting on the state of these special nodes trigger global avalanches leading to complete network reorganization.

/pdf/coevolution-of-dynamical-states-and-interactions-in-dynamic-i88tumyn73.pdf

Coevolution of dynamical states and interactions in dynamic networks.

Studies of cultural differentiation have shown that social mechanisms that normally lead to cultural convergence—homophily and influence—can also explain how distinct cultural groups can form. However, this emergent cultural diversity has proven to be unstable in the face of cultural drift—small errors or innovations that allow cultures to change from within. The authors develop a model of cultural differentiation that combines the traditional mechanisms of homophily and influence with a third mechanism of network homophily, in which network structure co-evolves with cultural interaction. Results show that in certain regions of the parameter space, these co-evolutionary dynamics can lead to patterns of cultural diversity that are stable in the presence of cultural drift. The authors address the implications of these findings for understanding the stability of cultural diversity in the face of increasing technological trends toward globalization.

/pdf/homophily-cultural-drift-and-the-co-evolution-of-cultural-2qe7zkn7l5.pdf

Homophily, Cultural Drift, and the Co-Evolution of Cultural Groups.

We analyze the ordering dynamics of the voter model in different classes of complex networks. We observe that whether the voter dynamics orders the system depends on the effective dimensionality of the interaction networks. We also find that when there is no ordering in the system, the average survival time of metastable states in finite networks decreases with network disorder and degree heterogeneity. The existence of hubs, i.e., highly connected nodes, in the network modifies the linear system size scaling law of the survival time. The size of an ordered domain is sensitive to the network disorder and the average degree, decreasing with both; however, it seems not to depend on network size and on the heterogeneity of the degree distribution.

/pdf/voter-model-dynamics-in-complex-networks-role-of-1dba9aiphn.pdf

Voter model dynamics in complex networks: Role of dimensionality, disorder, and degree distribution.

We study a coevolution voter model on a complex network. A mean-field approximationreveals an absorbing transition from an active to a frozen phase at a criticalvalue ${p}_{c}=\frac{\ensuremath{\mu}\ensuremath{-}2}{\ensuremath{\mu}\ensuremath{-}1}$ that only depends on the average degree $\ensuremath{\mu}$ ofthe network. In finite-size systems, the active and frozen phases correspondto a connected and a fragmented network, respectively. The transition canbe seen as the sudden change in the trajectory of an equivalent random walkat the critical point, resulting in an approach to the final frozen statewhose time scale diverges as $\ensuremath{\tau}\ensuremath{\sim}|{p}_{c}\ensuremath{-}p{|}^{\ensuremath{-}1}$ near ${p}_{c}$.

/pdf/generic-absorbing-transition-in-coevolution-dynamics-1jotkfsm9b.pdf

Generic Absorbing Transition in Coevolution Dynamics

We analyze the nonequilibrium order-disorder transition of Axelrod's model of social interaction in several complex networks. In a small-world network, we find a transition between an ordered homogeneous state and a disordered state. The transition point is shifted by the degree of spatial disorder of the underlying network, the network disorder favoring ordered configurations. In random scale-free networks the transition is only observed for finite size systems, showing system size scaling, while in the thermodynamic limit only ordered configurations are always obtained. Thus, in the thermodynamic limit the transition disappears. However, in structured scale-free networks, the phase transition between an ordered and a disordered phase is restored.

/pdf/nonequilibrium-transitions-in-complex-networks-a-model-of-5eb99j02fx.pdf

Maxi San Miguel

Papers

Coevolution of dynamical states and interactions in dynamic networks.

Homophily, Cultural Drift, and the Co-Evolution of Cultural Groups.

Voter model dynamics in complex networks: Role of dimensionality, disorder, and degree distribution.

Generic Absorbing Transition in Coevolution Dynamics

Nonequilibrium transitions in complex networks: a model of social interaction