scholarly journals From Local Growth to Global Optimization in Insect Built Networks

2012 ◽  
pp. 132-144 ◽  
Author(s):  
Andrea Perna ◽  
Pascale Kuntz ◽  
Guy Theraulaz ◽  
Christian Jost
Keyword(s):  
Network Topology ◽  
Social Insect ◽  
Network Formation ◽  
Functional Networks ◽  
Local Optima ◽  
Global Properties ◽  
External Conditions ◽  
Network Properties ◽  
Theoretical Considerations

Social insect colonies build large net-like systems: gallery and trail networks. Many such networks appear to show near-optimal performance. Focusing on the network system inside termite nests we address the question how simple agents with probabilistic behaviour can control and optimize the growth of a structure with size several magnitude orders above their perceptual range. We identify two major classes of mechanisms: (i) purely local mechanisms, which involve the arrangement of simple motifs according to predetermined rules of behaviour and (ii) local estimation of global quantities, where sizes, lengths, and numbers are estimated from densities, concentrations, and traffic. Theoretical considerations suggest that purely local mechanisms work better during early network formation and are less likely to fall into local optima. On the contrary, estimation of global properties is only possible on functional networks and is more likely to work through pruning. This latter mechanism may contribute to restore network functionalities following unpredicted changes of external conditions or network topology. An analysis of the network properties of Cubitermes termite nests supports the role of both classes of mechanisms, possibly in interplay with environmental conditions acting as a template.

Networks

2020 ◽  
pp. 534-562
Author(s):  
Matthew O. Jackson ◽  
Brian W. Rogers ◽  
Yves Zenou
Keyword(s):  
Social Networks ◽  
Social Network ◽  
Statistical Analysis ◽  
Labor Markets ◽  
Network Formation ◽  
Labor Market Outcomes ◽  
Negative Consequences ◽  
Social Scientists ◽  
Market Outcomes

What is the role of social networks in driving persistent differences between races and genders in education and labor market outcomes? What is the role of homophily in such differences? Why is such homophily seen even if it ends up with negative consequences in terms of labor markets? This chapter discusses social network analysis from the perspective of economics. The chapter is organized around the theme of externalities: the effects that one’s behavior has on others’ welfare. Externalities underlie the interdependencies that make networks interesting to social scientists. This chapter discusses network formation, as well as interactions between people’s behaviors within a given network, and the implications in a variety of settings. Finally, the chapter highlights some empirical challenges inherent in the statistical analysis of network-based data.

Key role of network formation in Rutting, fatigue and brittle performance of bitumen/PEG/MDI/SiO2 composites

2021 ◽  
Vol 296 ◽  
pp. 123739
Author(s):  
Tian Xia ◽  
Xiang Chen ◽  
Jianhui Xu ◽  
Anxin Zhang ◽  
Zhongli Wang ◽  
...  
Keyword(s):  
Network Formation

scholarly journals MicroRNA Mediating Networks in Granulosa Cells Associated with Ovarian Follicular Development

2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Baoyun Zhang ◽  
Long Chen ◽  
Guangde Feng ◽  
Wei Xiang ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Granulosa Cells ◽  
Messenger Rna ◽  
Expression Patterns ◽  
Follicular Development ◽  
Functional Networks ◽  
Signal Pathways ◽  
Differentially Expressed Mirnas ◽  
Selection Of

Ovaries, which provide a place for follicular development and oocyte maturation, are important organs in female mammals. Follicular development is complicated physiological progress mediated by various regulatory factors including microRNAs (miRNAs). To demonstrate the role of miRNAs in follicular development, this study analyzed the expression patterns of miRNAs in granulosa cells through investigating three previous datasets generated by Illumina miRNA deep sequencing. Furthermore, via bioinformatic analyses, we dissected the associated functional networks of the observed significant miRNAs, in terms of interacting with signal pathways and transcription factors. During the growth and selection of dominant follicles, 15 dysregulated miRNAs and 139 associated pathways were screened out. In comparison of different styles of follicles, 7 commonly abundant miRNAs and 195 pathways, as well as 10 differentially expressed miRNAs and 117 pathways in dominant follicles in comparison with subordinate follicles, were collected. Furthermore, SMAD2 was identified as a hub factor in regulating follicular development. The regulation of miR-26a/b onsmad2messenger RNA has been further testified by real time PCR. In conclusion, we established functional networks which play critical roles in follicular development including pivotal miRNAs, pathways, and transcription factors, which contributed to the further investigation about miRNAs associated with mammalian follicular development.

The Political role of the judiciary : The Belgian case

Res Publica ◽  
1970 ◽  
Vol 38 (2) ◽  
pp. 371-384
Author(s):  
Lode Van Outrive
Keyword(s):  
Easy Access ◽  
The Political ◽  
Access To Justice ◽  
Selection System ◽  
Advisory Body ◽  
Political Role ◽  
Administration Of Justice ◽  
External Conditions ◽  
Recruitment And Selection

We set out by tracking the political vicissitudes of the administration of justice and their connections with a range of phenomena: the neglect by politicians; a series of events and scandals and the very curious reactions of the judicial apparatus; several parliamentary investigation commissions without much effect. Then we take a critical look at partisan politicisation of the magistrature: negative evalution of their output thrives to it; but there are also partisan appointments and promotions, even absence and refusal of training. Many contextual factors hinder a normal, acceptable process of politicisation: over- and underregulation, bad legislation, misconception on contra! over the administration of justice and over judges, non-democratic decisionmaking within the organisation of the magistrature, the development of wrong relationship inside the trias politica; but also other more external conditions were not met neither.  We wind up with an examination of the assesment of recent governmental proposals: an improvement of criminal and judicial inquiries; foundation of a national advisory body for the magistrature; simplification of the legislation; modernisation of the courts activities; a more objective recruitment and selection system; more easy access to justice etc. The question raises as to wether it suffices to tinker with the sy stem of the administration of justice alone ... Between the Belgian and the Italian situations are similarities and relevant differences. 

scholarly journals On Synchronizing Coupled Retinogeniculocortical Pathways: A Toy Model

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
B. L. Mayer ◽  
L. H. A. Monteiro
Keyword(s):  
Neural Network ◽  
Visual Cortex ◽  
Corpus Callosum ◽  
Neuronal Activity ◽  
Network Topology ◽  
Cerebral Hemisphere ◽  
State Transition ◽  
Regular Lattice ◽  
Visual Cortices

A Newman-Watts graph is formed by including random links in a regular lattice. Here, the emergence of synchronization in coupled Newman-Watts graphs is studied. The whole neural network is considered as a toy model of mammalian visual pathways. It is composed by four coupled graphs, in which a coupled pair represents the lateral geniculate nucleus and the visual cortex of a cerebral hemisphere. The hemispheres communicate with each other through a coupling between the graphs representing the visual cortices. This coupling makes the role of the corpus callosum. The state transition of neurons, supposed to be the nodes of the graphs, occurs in discrete time and it follows a set of deterministic rules. From periodic stimuli coming from the retina, the neuronal activity of the whole network is numerically computed. The goal is to find out how the values of the parameters related to the network topology affect the synchronization among the four graphs.

scholarly journals The Constant Changes in US Strategy in Afghanistan: Achievement or Failure

2017 ◽  
Vol 10 (2) ◽  
pp. 41
Author(s):  
Behnam Sahranavard ◽  
Ali Asghar Kazemi
Keyword(s):  
United States ◽  
Decision Making ◽  
September 11 ◽  
International Terrorism ◽  
Basic Question ◽  
Collection Method ◽  
External Conditions ◽  
Post September 11 ◽  
The Given

The nations take various strategies in exposure to different developments and phenomena and impact on foreign and internal policies of countries in international scene proportional to their internal and external conditions and rivals and at international arena. What US implemented after September 11 Event and targeted accusation finger toward Taliban and Al-Qaeda in Afghanistan is deemed as a type of strategy that has occurred in created nostalgic climate together with hasty decision making and negligence to domestic issues in Afghan Community while their output was to take different and even paradoxical strategies in this crisis-stricken region since 1980s. In this article that has been written in order to analyze US Post September- 11 Strategies in Afghanistan this basic question will be answered that how changes in US macro policies influenced in orientation of diplomacy of this country and why this country has adapted different policies in occupation of Afghanistan. Afterwards, it is deduced according to the given findings from librarian data collection method that the constant changes in US strategy in Afghanistan were due to overlooking of domestic issues and historic, ethnic, cultural, political, and ideological complexities of this country that has resulted in degradation of US position in world scene and its failure in suppression of Taliban.This article has been excerpted from my PhD treatise under title of ‘The role of United States in the regional crisis (e.g. Afghan and Iraqi crises) and the rise of revolutionary and radicalism on the emergence of international terrorism’.

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