scholarly journals Gompertz Law in Clean Foam Coalescence

2021 ◽  
Vol 9 ◽  
Author(s):  
Gun Oh ◽  
Marta Gonçalves ◽  
Byung Mook Weon

Clean foams tend to age with time through sequential coalescence events. This study evaluates aging dynamics in clean foams by measuring bubble populations from coalescence simulation experiments and adopting biological population dynamics analysis. The population dynamics of bubbles in clean foams during coalescence show that the mortality rates of individual bubbles change exponentially with time, regardless of initial simulation conditions, consistent with the Gompertz mortality law commonly observed in biological aging. This result would be beneficial in understanding the aging dynamics of clean foams.

2001 ◽  
Vol 12 (07) ◽  
pp. 1067-1073 ◽  
Author(s):  
DANUTA MAKOWIEC ◽  
DIETRICH STAUFFER ◽  
MARIUSZ ZIELIŃSKI

It is shown that if the computer model of biological aging proposed by Stauffer is modified such that the late reproduction is privileged, then the Gompertz law of exponential increase of mortality can be retrieved.


2016 ◽  
Vol 76 (1) ◽  
pp. 45-54 ◽  
Author(s):  
K. A. Silva ◽  
J. M. F. F. Santos ◽  
J. R. Andrade ◽  
E. N. Lima ◽  
U. P. Albuquerque ◽  
...  

Abstract Variation in annual rainfall is considered the most important factor influencing population dynamics in dry environments. However, different factors may control population dynamics in different microhabitats. This study recognizes that microhabitat variation may attenuate the influence of climatic seasonality on the population dynamics of herbaceous species in dry forest (Caatinga) areas of Brazil. We evaluated the influence of three microhabitats (flat, rocky and riparian) on the population dynamics of four herbaceous species (Delilia biflora, Commelina obliqua, Phaseolus peduncularis and Euphorbia heterophylla) in a Caatinga (dry forest) fragment at the Experimental Station of the Agronomic Research Institute of Pernambuco in Brazil, over a period of three years. D. biflora, C. obliqua and P. peduncularis were found in all microhabitats, but they were present at low densities in the riparian microhabitat. There was no record of E. heterophylla in the riparian microhabitat. Population size, mortality rates and natality rates varied over time in each microhabitat. This study indicates that different establishment conditions influenced the population size and occurrence of the four species, and it confirms that microhabitat can attenuate the effect of drought stress on mortality during the dry season, but the strength of this attenuator role may vary with time and species.


Author(s):  
Anna Clara Balbina Silva ◽  
Afonso Pelli

Compreender os mecanismos que regulam a dinâmica das populações espacialmente estruturadas é um desafio crítico para os ecólogos e gestores de conservação. A dinâmica de populações é um ramo da ecologia que estuda as populações como sistema em atividades, relacionando as influências ambientais com a distribuição e abundância dos indivíduos e suas interações com o ambiente. O presente artigo é uma revisão bibliográfica, com o objetivo de identificar produções científicas relevantes sobre dinâmica populacional. Para isso, foram utilizados periódicos revisados por pares, na base de Periódicos Capes. A pesquisa foi realizada em junho de 2019, utilizando-se as palavras-chave para título contendo: "population dynamics" e no assunto “ecology”, a partir de 2014, quando o texto completo estava disponível. Foram considerados como critérios de exclusão os artigos publicados antes de 2014. Após a leitura dos títulos dos artigos, foram selecionados 34 artigos que foram lidos na íntegra. Em livros disponíveis no acervo da biblioteca da Universidade Federal do Triângulo Mineiro, foram selecionados quatro livros no tema dinâmica populacional. O referencial teórico aborda os aspectos da dinâmica de populações, tabela de vida, formas de crescimento e interações populacionais. Ressalta-se a necessidade de novos estudos que ainda possuem lacunas, que venha complementar e contribuir para o conhecimento de organismos que faltam ou ainda não possuem registros de estudos. Palavras-chave: Taxas de Natalidade e Mortalidade. Atributos Populacionais. Dispersão. AbstractUnderstanding the mechanisms that regulate the dynamics of spatially structured populations is a critical challenge for ecologists and conservation managers. Population dynamics is a branch of ecology that studies populations as a system in activities, relating environmental influences to the individuals’ distribution and abundance and their interactions with the environment. This article is a bibliographic review, aiming to identify relevant scientific productions about population dynamics. Thus. peer-reviewed journals were used in the Capes Periodicals base, the research was conducted in June 2019, using the keywords for title containing "population dynamics" and in the subject "ecology", from 2014, when the full text was available. Exclusion criteria were: articles published before 2014, after reading the article titles, 34 articles were selected that met the initially proposed criteria and were read in full. In books available in the library collection of the Federal University of Triângulo Mineiro, with a search for the dynamic population theme, 4 books were used. The theoretical framework addresses the aspects of population dynamics, life table, forms of growth and population interactions. It is emphasized  the need for further studies that still have gaps, which will complement and contribute to the knowledge of organisms that are missing or do not have study records. Keywords: Birth and Mortality Rates. Population Attributes. Dispersion.


1981 ◽  
Vol 59 (12) ◽  
pp. 2350-2359 ◽  
Author(s):  
B. Vincent ◽  
G. Vaillancourt ◽  
N. Lafontaine

The population dynamics of Pisidium amnicum have been studied in one population of the St. Lawrence River over a 2-year period during which 19 samples were taken. The species can live up to 3 years and it is iteroparous; individuals generally attain sexual maturity after 1 year and they reproduce twice, once at 2 and once at 3 years of age. In adults, mortality is lower in winter than during the rest of the year and mortality rates are twice as high during the 1st year than during the 2nd year. Total dry weight (PT, in milligrams) is related to maximum length (L, in millimetres) according to the equation PT = 0.0283∙L3,80 and flesh dry weight (PC, in milligrams) is related to length as follows: PC = 0.007∙L3,18. The annual production to mean biomass (P/B) ratio is 1.4, the mean annual production being 1.298 mg/m2 of total dry weight and 107 mg/m2 of flesh weight. Comparing these results with those obtained for the gastropod Bithynia tentaculata in the same environment and at the same period of the year has shown that the growth of Pisidium amnicum is far less influenced by the temperature regime than that of the other species and that its production is at least 10 times lower.


2012 ◽  
Vol 93 ◽  
pp. 47-57 ◽  
Author(s):  
Michael R. Heath ◽  
Jens Rasmussen ◽  
Martin C. Bailey ◽  
John Dunn ◽  
John Fraser ◽  
...  

1977 ◽  
Vol 34 (11) ◽  
pp. 2030-2040 ◽  
Author(s):  
Walter T. Momot ◽  
Howard Gowing

Fluctuations in mortality rather than in growth rates produced most of the year-to-year differences in biomass accumulation of three different populations of the crayfish Orconectes virilis. Yearly biomass changes resulted from density-dependent control of mortality and fecundity during certain portions of the life cycle. Density-dependent changes in mortality rates controlled population size for adults in all lakes and for young-of-the-year in two of the three study lakes. Growth rates were much less responsive to fluctuating densities. Disparity between the number of ovarian and attached eggs increased as density of age I+ crayfish increased. This provided a strong density regulator on fecundity. Differences occurred in the number of recruits produced by a brood stock that survive to the end of the first growing season in the various lakes. Yet the number of females surviving to reproductive age 2 yr later was strongly regulated. Strong population regulation produced two female recruits of breeding age for every two–six parental breeding females. The high biomass and production levels of crayfish discovered in West Lost Lake in 1962–63 also occurred in the other area lakes. Higher but variable levels of recruitment resulted in larger standing crops and production in West Lost lake. This resulted from less effective density controls on the mortality rates of younger age-groups in that lake. Despite great variation in biomass of from 46 to 213 kg/ha and annual production from 60 to 142 kg/ha, the annual turnover ratio of the biomass was found to vary only between 0.94 and 1.53. Key words: crayfish, Orconectes virilis, population dynamics, annual production, Michigan lakes


Sign in / Sign up

Export Citation Format

Share Document