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

http://www.maths.qmul.ac.uk/%7Elatora/report_06.pdf

Complex networks: Structure and dynamics

A key aim of postgenomic biomedical research is to systematically catalogue all molecules and their interactions within a living cell. There is a clear need to understand how these molecules and the interactions between them determine the function of this enormously complex machinery, both in isolation and when surrounded by other cells. Rapid advances in network biology indicate that cellular networks are governed by universal laws and offer a new conceptual framework that could potentially revolutionize our view of biology and disease pathologies in the twenty-first century.

/pdf/network-biology-understanding-the-cell-s-functional-589nl2mnk6.pdf

Network biology: understanding the cell's functional organization

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

Communication/transportation systems are often subjected to failures and attacks. Here we represent such systems as networks and we study their ability to resist failures (attacks) simulated as the breakdown of a group of nodes of the network chosen at random (chosen accordingly to degree or load). We consider and compare the results for two different network topologies: the Erdos–Renyi random graph and the Barabasi–Albert scale-free network. We also discuss briefly a dynamical model recently proposed to take into account the dynamical redistribution of loads after the initial damage of a single node of the network.

/pdf/error-and-attack-tolerance-of-complex-networks-2170zc1znz.pdf

Error and attack tolerance of complex networks

Large but rare cascades triggered by small initial shocks are present in most of the infrastructure networks. Here we present a simple model for cascading failures based on the dynamical redistribution of the flow on the network. We show that the breakdown of a single node is sufficient to collapse the efficiency of the entire system if the node is among the ones with largest load. This is particularly important for real-world networks with a highly hetereogeneous distribution of loads as the Internet and electrical power grids.

/pdf/model-for-cascading-failures-in-complex-networks-1vyyl4xdo0.pdf

Model for cascading failures in complex networks

The application of the network approach to the urban case poses several questions in terms of how to deal with metric distances, what kind of graph representation to use, what kind of measures to investigate, how to deepen the correlation between measures of the structure of the network and measures of the dynamics on the network, what are the possible contributions from the GIS community. In this paper, the author considers six cases of urban street networks characterized by different patterns and historical roots. The authors propose a representation of the street networks based firstly on a primal graph, where intersections are turned into nodes and streets into edges. In a second step, a dual graph, where streets are nodes and intersections are edges, is constructed by means of a generalization model named Intersection Continuity Negotiation, which allows to acknowledge the continuity of streets over a plurality of edges. Finally, the authors address a comparative study of some structural properties of the dual graphs, seeking significant similarities among clusters of cases. A wide set of network analysis techniques are implemented over the dual graph: in particular the authors show that the absence of any clue of assortativity differentiates urban street networks from other non-geographic systems and that most of the considered networks have a broad degree distribution typical of scale-free networks and exhibit small-world properties as well.

/pdf/the-network-analysis-of-urban-streets-a-dual-approach-57sq5ufcpd.pdf

The network analysis of urban streets: A dual approach

The network metaphor in the analysis of urban and territorial cases has a long tradition, especially in transportation or land-use planning and economic geography. More recently, urban design has brought its contribution by means of the ‘space syntax’ methodology. All these approaches-though under different terms like ‘accessibility’, ‘proximity’, ‘integration’ ‘connectivity’, ‘cost’, or ‘effort’-focus on the idea that some places (or streets) are more important than others because they are more central. The study of centrality in complex systems, however, originated in other scientific areas, namely in structural sociology, well before its use in urban studies; moreover, as a structural property of the system, centrality has never been extensively investigated metrically in geographic networks as it has been topologically in a wide range of other relational networks such as social, biological, or technological ones. After a previous work on some structural properties of the primal graph representation of...

The Network Analysis of Urban Streets: A Primal Approach:

The North American power grid is one of the most complex technological
networks, and its interconnectivity allows both for long-distance power
transmission and for the propagation of disturbances. We model the power
grid using its actual topology and plausible assumptions about the load
and overload of transmission substations. Our results indicate that the 
loss of a single substation
can result in up to $25\%$
 loss of transmission efficiency by triggering 
an overload cascade in the network. The actual transmission loss depends
on the overload tolerance of the network and the connectivity of the 
failed substation. 
We systematically study the damage inflicted by the loss of single nodes, 
and find three universal behaviors, suggesting that $40\%$
 of the transmission 
substations lead to cascading failures when disrupted. While the loss of a single
node can inflict substantial damage, subsequent removals have only incremental effects, 
in agreement with the topological resilience to less than $1\%$
 node loss.

/pdf/modeling-cascading-failures-in-the-north-american-power-grid-4eef69nfjm.pdf

Paolo Crucitti

Papers

Error and attack tolerance of complex networks

Model for cascading failures in complex networks

The network analysis of urban streets: A dual approach

The Network Analysis of Urban Streets: A Primal Approach:

Modeling cascading failures in the North American power grid