scholarly journals A note on the relation between Hartnell’s firefighter problem and growth of groups

2018 ◽  
Vol 33 ◽  
pp. 55-60
Author(s):  
Eduardo Martínez-Pedroza
Keyword(s):  
Growth Of Groups ◽  
Firefighter Problem

scholarly journals Corrigendum to “On the dimension growth of groups” [J. Algebra 347 (1) (2011) 23–39]

2012 ◽  
Vol 370 ◽  
pp. 407-409 ◽  
Author(s):  
Alexander Dranishnikov ◽  
Mark Sapir
Keyword(s):  
Growth Of Groups

scholarly journals ON THE GROWTH OF GROUPS AND AUTOMORPHISMS

2005 ◽  
Vol 15 (05n06) ◽  
pp. 869-874 ◽  
Author(s):  
MARTIN R. BRIDSON
Keyword(s):  
Finitely Generated ◽  
Free Products ◽  
Dehn Functions ◽  
Amalgamated Free Products ◽  
Growth Functions ◽  
Growth Of Groups

We consider the growth functions βΓ(n) of amalgamated free products Γ = A *C B, where A ≅ B are finitely generated, C is free abelian and |A/C| = |A/B| = 2. For every d ∈ ℕ there exist examples with βΓ(n) ≃ nd+1βA(n). There also exist examples with βΓ(n) ≃ en. Similar behavior is exhibited among Dehn functions.

scholarly journals “BETTER AND HAPPIER MEN AND WOMEN”: THE AGRICULTURAL INSTRUCTION ACT, 1913-1924

2004 ◽  
pp. 257-285
Author(s):  
Linda M. Ambrose
Keyword(s):  
Women's Groups ◽  
Men And Women ◽  
Canadian Government ◽  
Growth Of Groups ◽  
Women’S Groups ◽  
Farming Industry

In 1913, the Canadian government introduced The Agricultural Instruction Act, a measure which granted ten million dollars to the provinces over ten years to aid agriculture. The Conservatives predicted that the Act would help in “aiding and advancing the farming industry by instruction in agriculture” but this paper argues that, ironically, the funding actually served to heighten rural discontent, not assuage it. By examining public documents and the rural press, the paper explores the rationale, rhetoric, and politics of this initiative. The funding designated for women’s groups is closely examined to determine its impact on the growth of groups like the Women’s Institutes.

scholarly journals Locally adaptive Bayesian birth-death model successfully detects slow and rapid rate shifts

2019 ◽  
Author(s):  
Andrew F. Magee ◽  
Sebastian Höhna ◽  
Tetyana I. Vasylyeva ◽  
Adam D. Leaché ◽  
Vladimir N. Minin
Keyword(s):  
Random Field ◽  
Markov Random Field ◽  
Death Process ◽  
Rate Variation ◽  
Rapid Rate ◽  
Birth Rates ◽  
Death Rates ◽  
Growth Of Groups ◽  
Markov Random ◽  
Birth Death

AbstractBirth-death processes have given biologists a model-based framework to answer questions about changes in the birth and death rates of lineages in a phylogenetic tree. Therefore birth-death models are central to macroevolutionary as well as phylodynamic analyses. Early approaches to studying temporal variation in birth and death rates using birth-death models faced difficulties due to the restrictive choices of birth and death rate curves through time. Sufficiently flexible time-varying birth-death models are still lacking. We use a piecewise-constant birth-death model, combined with both Gaussian Markov random field (GMRF) and horseshoe Markov random field (HSMRF) prior distributions, to approximate arbitrary changes in birth rate through time. We implement these models in the widely used statistical phylogenetic software platform RevBayes, allowing us to jointly estimate birth-death process parameters, phylogeny, and nuisance parameters in a Bayesian framework. We test both GMRF-based and HSMRF-based models on a variety of simulated diversification scenarios, and then apply them to both a macroevolutionary and an epidemiological dataset. We find that both models are capable of inferring variable birth rates and correctly rejecting variable models in favor of effectively constant models. In general the HSMRF-based model has higher precision than its GMRF counterpart, with little to no loss of accuracy. Applied to a macroevolutionary dataset of the Australian gecko family Pygopodidae (where birth rates are interpretable as speciation rates), the GMRF-based model detects a slow decrease whereas the HSMRF-based model detects a rapid speciation-rate decrease in the last 12 million years. Applied to an infectious disease phylodynamic dataset of sequences from HIV subtype A in Russia and Ukraine (where birth rates are interpretable as the rate of accumulation of new infections), our models detect a strongly elevated rate of infection in the 1990s.Author summaryBoth the growth of groups of species and the spread of infectious diseases through populations can be modeled as birth-death processes. Birth events correspond either to speciation or infection, and death events to extinction or becoming noninfectious. The rates of birth and death may vary over time, and by examining this variation researchers can pinpoint important events in the history of life on Earth or in the course of an outbreak. Time-calibrated phylogenies track the relationships between a set of species (or infections) and the times of all speciation (or infection) events, and can thus be used to infer birth and death rates. We develop two phylogenetic birth-death models with the goal of discerning signal of rate variation from noise due to the stochastic nature of birth-death models. Using a variety of simulated datasets, we show that one of these models can accurately infer slow and rapid rate shifts without sacrificing precision. Using real data, we demonstrate that our new methodology can be used for simultaneous inference of phylogeny and rates through time.

Growth of Groups

2017 ◽  
pp. 237-266
Author(s):  
Eric Freden
Keyword(s):  
Growth Of Groups

Growth of groups

1999 ◽  
pp. 139-151
Author(s):  
Günter Krause ◽  
Thomas Lenagan
Keyword(s):  
Growth Of Groups
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