scholarly journals Network Architecture and Mutational Sensitivity of the C. elegans Metabolome

2017 ◽  
Author(s):  
Lindsay M. Johnson ◽  
Luke M. Chandler ◽  
Sarah K. Davies ◽  
Charles F. Baer
Keyword(s):  
Metabolic Network ◽  
Shortest Path ◽  
Network Architecture ◽  
Path Length ◽  
Spontaneous Mutation ◽  
Network Centrality ◽  
Topological Properties ◽  
C Elegans ◽  
Evolutionary Forces ◽  
The Relationship

AbstractA fundamental issue in evolutionary systems biology is understanding the relationship between the topological architecture of a biological network, such as a metabolic network, and the evolution of the network. The rate at which an element in a metabolic network accumulates genetic variation via new mutations depends on both the size of the mutational target it presents and its robustness to mutational perturbation. Quantifying the relationship between topological properties of network elements and the mutability of those elements will facilitate understanding the variation in and evolution of networks at the level of populations and higher taxa.We report an investigation into the relationship between two topological properties of 29 metabolites in the C. elegans metabolic network and the sensitivity of those metabolites to the cumulative effects of spontaneous mutation. The relationship between several measures of network centrality and sensitivity to mutation is weak, but point estimates of the correlation between network centrality and mutational variance are positive, with only one exception. There is a marginally significant correlation between core number and mutational heritability. There is a small but significant negative correlation between the shortest path length between a pair of metabolites and the mutational correlation between those metabolites.Positive association between the centrality of a metabolite and its mutational heritability is consistent with centrally-positioned metabolites presenting a larger mutational target than peripheral ones, and is inconsistent with centrality conferring mutational robustness, at least in toto. The weakness of the correlation between shortest path length and the mutational correlation between pairs of metabolites suggests that network locality is an important but not overwhelming factor governing mutational pleiotropy. These findings provide necessary background against which the effects of other evolutionary forces, most importantly natural selection, can be interpreted.

scholarly journals On the Relationship between City Mobility and Blocks Uniformity

Proceedings ◽  
2019 ◽  
Vol 46 (1) ◽  
pp. 22
Author(s):  
Eric Tokuda ◽  
Cesar Comin ◽  
Roberto Cesar ◽  
Luciano Costa
Keyword(s):  
Shortest Path ◽  
Real World ◽  
Path Length ◽  
Spatial Organization ◽  
Great Influence ◽  
World Cities ◽  
Topological Organization ◽  
The Relationship ◽  
The City

The spatial organization and the topological organization of cities have a great influence on the lives of their inhabitants, including mobility efficiency. Entropy has been often adopted for the characterization of diverse natural and human-made systems and structures. In this work, we apply the exponential of entropy (evenness) to characterize the uniformity of city blocks. It is suggested that this measurement is related to several properties of real cities, such as mobility. We consider several real-world cities, from which the logarithm of the average shortest path length is also calculated and compared with the evenness of the city blocks. Several interesting results have been found, as discussed in the article.

scholarly journals Topological measures for identifying and predicting the spread of complex contagions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Douglas Guilbeault ◽  
Damon Centola
Keyword(s):  
Social Networks ◽  
Shortest Path ◽  
Empirical Data ◽  
Path Length ◽  
Centrality Measures ◽  
Social Phenomena ◽  
Node Centrality ◽  
Network Connectedness ◽  
Topological Measures ◽  
Definition Of

AbstractThe standard measure of distance in social networks – average shortest path length – assumes a model of “simple” contagion, in which people only need exposure to influence from one peer to adopt the contagion. However, many social phenomena are “complex” contagions, for which people need exposure to multiple peers before they adopt. Here, we show that the classical measure of path length fails to define network connectedness and node centrality for complex contagions. Centrality measures and seeding strategies based on the classical definition of path length frequently misidentify the network features that are most effective for spreading complex contagions. To address these issues, we derive measures of complex path length and complex centrality, which significantly improve the capacity to identify the network structures and central individuals best suited for spreading complex contagions. We validate our theory using empirical data on the spread of a microfinance program in 43 rural Indian villages.

scholarly journals Application of intelligent orienteering based on Internet of things

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Donghui Zhang ◽  
Ruijie Liu
Keyword(s):  
Internet Of Things ◽  
Network Architecture ◽  
Emergency Services ◽  
Simulation Experiment ◽  
Experimental Studies ◽  
Signal Stability ◽  
Anchor Nodes ◽  
Set Up ◽  
The Relationship ◽  
The Internet Of Things

Abstract Orienteering has gradually changed from a professional sport to a civilian sport. Especially in recent years, orienteering has been widely popularized. Many colleges and universities in China have also set up this course. With the improvement of people’s living conditions, orienteering has really become a leisure sport in modern people’s life. The reduced difficulty of sports enables more people to participate, but it also exposes a series of problems. As the existing positioning technology is relatively backward, the progress in personnel tracking, emergency services, and other aspects is slow. To solve these problems, a new intelligent orienteering application system is developed based on the Internet of things. ZigBee network architecture is adopted in the system. ZigBee is the mainstream scheme in the current wireless sensor network technology, which has many advantages such as convenient carrying, low power consumption, and signal stability. Due to the complex communication environment in mobile signal, the collected information is processed by signal amplification and signal anti-interference technology. By adding anti-interference devices, video isolators and other devices, the signal is guaranteed to the maximum extent. In order to verify the actual effect of this system, through a number of experimental studies including the relationship between error and traffic radius and the relationship between coverage and the number of anchor nodes, the data shows that the scheme studied in this paper has a greater improvement in comprehensive performance than the traditional scheme, significantly improving the accuracy and coverage. Especially the coverage is close to 100% in the simulation experiment. This research has achieved good results and can be widely used in orienteering training and competition.

scholarly journals SPONTANEOUS UNSTABLE UNC-22 IV MUTATIONS IN C. ELEGANS VAR. BERGERAC

Genetics ◽  
1984 ◽  
Vol 108 (4) ◽  
pp. 859-877
Author(s):  
D G Moerman ◽  
R H Waterston
Keyword(s):  
Mutation Frequency ◽  
Spontaneous Mutation ◽  
Phenotypic Effect ◽  
C Elegans ◽  
High Mutation Frequency ◽  
Mutator Activity ◽  
Discrete Site ◽  
Unstable Mutations ◽  
Spontaneous Mutation Frequency ◽  
Forward Mutation

ABSTRACT This paper describes a mutator system in the nematode Caenorhabditis elegans var. Bergerac for the gene unc-22. Of nine C. elegans and two C. briggsae strains tested only the Bergerac BO strain yielded mutant animals at a high frequency and the unc-22 IV gene is a preferred mutational target. The forward spontaneous mutation frequency at the unc-22 locus in Bergerac BO is about 1 × 10-4, and most of these spontaneous unc-22 mutations revert at frequencies between 2 × 10-3 and 2 × 10-4. Both the forward mutation frequency and the reversion frequency are sensitive to genetic background. Spontaneous unc-22 mutations derived in a Bergerac background and placed in a primarily Bristol background revert at frequencies of <10-6. When reintroduced into a Bergerac/Bristol hybrid background the mutations once again become unstable. The mutator activity could not be localized to a discrete site in the Bergerac genome. Nor did mutator activity require the Bergerac unc-22 gene as a target since the Bristol unc-22 homolog placed in a Bergerac background also showed high mutation frequency. Intragenic mapping of two spontaneous unc-22 alleles, st136 and st137, place both mutations in the central region of the known unc-22 map. However, these mutations probably recombine with one another, suggesting that the unstable mutations can occur in more than one site in unc-22. Examination of the phenotypic effect of these mutations on muscle structure indicates that they are less severe in their effect than a known amber allele. We suggest that this mutator system is polygenic and dispersed over the nematode genome and could represent activity of the transposable element Tc1.

scholarly journals Remarks on neighborhood star-Lindelöf spaces II

Filomat ◽  
2013 ◽  
Vol 27 (5) ◽  
pp. 875-880
Author(s):  
Yan-Kui Song
Keyword(s):  
Open Cover ◽  
Countable Subset ◽  
Topological Properties ◽  
Pseudocompact Spaces ◽  
The Relationship

A space X is said to be neighborhood star-Lindel?f if for every open cover U of X there exists a countable subset A of X such that for every open O?A, X=St(O,U). In this paper, we continue to investigate the relationship between neighborhood star-Lindel?f spaces and related spaces, and study topological properties of neighborhood star-Lindel?f spaces in the classes of normal and pseudocompact spaces. .

scholarly journals Study on the Influence of Urban Spatial Connection of Beijing Tianjin Hebei Urban Agglomeration on Total factor Productivity

2020 ◽  
Vol 206 ◽  
pp. 02010
Author(s):  
Wang Hongmei ◽  
Lu Zhihui
Keyword(s):  
Industrial Structure ◽  
Network Centrality ◽  
Connection Strength ◽  
External Effect ◽  
Factor Productivity ◽  
Positive Role ◽  
Centrality Index ◽  
Main Factors ◽  
City Cluster ◽  
The Relationship

The development of a city can not be separated from the connection with the outside world. A city can benefit from the external effect of the connection network with other cities. This paper studies the relationship between cities’ connection strength and TFP according to the network centrality index, which measures the level of the connection between cities. It is found that the connection between cities has a significant positive role in promoting the TFP of cities in a city cluster. The differences of labor scale, industrial structure and openness are the main factors that affect the connection between cities.

scholarly journals Transcranial direct current stimulation alters functional network structure in humans

2018 ◽  
Author(s):  
M. Ruttorf ◽  
S. Kristensen ◽  
L.R. Schad ◽  
J. Almeida
Keyword(s):  
Neuronal Activity ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Network Architecture ◽  
Functional Magnetic Resonance ◽  
Resonance Imaging ◽  
Direct Current Stimulation ◽  
Brain States ◽  
The Relationship ◽  
Central Tool

AbstractTranscranial direct current stimulation (tDCS) is routinely used in basic and clinical research, but its efficacy has been challenged on a methodological and statistical basis recently. The arguments against tDCS derive from insufficient understanding of how this technique interacts with brain processes physiologically. Because of its potential as a central tool in neuroscience, it is important to clarify whether and how tDCS affects neuronal activity. Here, we investigate influences of offline tDCS on network architecture measured by functional magnetic resonance imaging. Our results reveal a tDCS-induced reorganisation of a functionally-defined network that is dependent on whether we are exciting or inhibiting a node within this network, confirming in a functioning brain, and in a bias free and independent fashion that tDCS influences neuronal activity. Moreover, our results suggest that network-specific connectivity has an important role in defining the effects of tDCS and the relationship between brain states and behaviour.

Model of Product Warranty Network and its Robustness

2012 ◽  
Vol 482-484 ◽  
pp. 2165-2169
Author(s):  
Jian Yu ◽  
Zhen Zhang
Keyword(s):  
Shortest Path ◽  
Evolutionary Model ◽  
Important Index ◽  
Product Warranty ◽  
The Relationship ◽  
Random Failures

Robustness is an important index to assess the performance of product warranty network, and it’s helpful for managing the relationship between the manufacturers and the suppliers to analyze it. The paper establishes product warranty network’s evolutionary model according to its characteristics, and chooses the average shortest path as the measures of robustness to analyze the robustness of model of product warranty network under the random attack and the selective attack. The conclusions show that the product warranty network have strong tolerance against random failures yet are fragile under selective attacks.

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