ON MODELING THE GROWTH DYNAMICS OF A STAGE STRUCTURED POPULATION

2013 ◽  
Vol 06 (06) ◽  
pp. 1350039 ◽  
Author(s):  
GIUSEPPE BUFFONI ◽  
SARA PASQUALI
Keyword(s):  
Numerical Simulations ◽  
Temporal Dynamics ◽  
Growth Dynamics ◽  
Biological Processes ◽  
Dispersion Models ◽  
Development Models ◽  
Regression Effects ◽  
Pelagic Copepod ◽  
Structured Population ◽  
Lagrangian Modeling

A Lagrangian modeling approach is applied to the numerical simulation of the temporal dynamics of a stage-structured population. The growth dynamics is determined only by the main biological processes: development of an individual, mortality, reproduction. Different approaches in modeling the development process of an individual are implemented: stochastic advection-diffusion models (backward–forward dispersion models), and stochastic development models where regression effects, defined as negative development on the status of an individual, are forbidden (forward dispersion models). Some properties of the residence times of an individual in a stage are investigated: in particular, their role in the calibration of the development models and in the estimation of some parameters introduced in the model equation. As a study case a multi-stage pelagic copepod population is considered. Trying to separate the effects of the main biological processes on the temporal dynamics, numerical simulations have been carried out in some idealized situations: first only the development of the individuals, neglecting mortality and reproduction, is considered; then the mortality process is introduced, and finally both the mortality and reproduction processes. The results of the numerical simulations, are compared and discussed.

scholarly journals Temporal transcriptomic differences between tolerant and susceptible genotypes contribute to rice drought tolerance

BMC Genomics ◽  
2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Hui Xia ◽  
Xiaosong Ma ◽  
Kai Xu ◽  
Lei Wang ◽  
Hongyan Liu ◽  
...  
Keyword(s):  
Drought Tolerance ◽  
Iron Transport ◽  
Ferric Iron ◽  
Temporal Dynamics ◽  
Histone Deacetylation ◽  
System Level ◽  
Biological Processes ◽  
Drought Period ◽  
Recovery Stage ◽  
Rice Genotypes

Abstract Background Drought-tolerance ensures a crop to maintain life activities and protect cell from damages under dehydration. It refers to diverse mechanisms temporally activated when the crop adapts to drought. However, knowledge about the temporal dynamics of rice transcriptome under drought is limited. Results Here, we investigated temporal transcriptomic dynamics in 12 rice genotypes, which varied in drought tolerance (DT), under a naturally occurred drought in fields. The tolerant genotypes possess less differentially expressed genes (DEGs) while they have higher proportions of upregulated DEGs. Tolerant and susceptible genotypes have great differences in temporally activated biological processes (BPs) during the drought period and at the recovery stage based on their DEGs. The DT-featured BPs, which are activated specially (e.g. raffinose, fucose, and trehalose metabolic processes, etc.) or earlier in the tolerant genotypes (e.g. protein and histone deacetylation, protein peptidyl-prolyl isomerization, transcriptional attenuation, ferric iron transport, etc.) shall contribute to DT. Meanwhile, the tolerant genotypes and the susceptible genotypes also present great differences in photosynthesis and cross-talks among phytohormones under drought. A certain transcriptomic tradeoff between DT and productivity is observed. Tolerant genotypes have a better balance between DT and productivity under drought by activating drought-responsive genes appropriately. Twenty hub genes in the gene coexpression network, which are correlated with DT but without potential penalties in productivity, are recommended as good candidates for DT. Conclusions Findings of this study provide us informative cues about rice temporal transcriptomic dynamics under drought and strengthen our system-level understandings in rice DT.

Reflective Evolution Under Strategic Uncertainty

2019 ◽  
Vol 29 (02) ◽  
pp. 1950018 ◽  
Author(s):  
Arnaud Z. Dragicevic
Keyword(s):  
Population Dynamics ◽  
Numerical Simulations ◽  
Evolutionary Model ◽  
Competition Strategy ◽  
Strategic Uncertainty ◽  
Bifurcation Diagrams ◽  
Structured Population ◽  
To Come ◽  
The Impact ◽  
Negative Strategy

We consider population dynamics of agents who can both play the cooperative strategy and the competition strategy but ignore whether the game to come will be cooperative or noncooperative. For that purpose, we propose an evolutionary model, built upon replicator(–mutator) dynamics under strategic uncertainty, and study the impact of update decay. In replicator–mutator dynamics, we find that the strategy replication under certain mutation in an unstructured population is equivalent to a negative strategy replication in a structured population. Likewise, in replicator–mutator dynamics with decay, the strategy replication under certain mutation in a structured population is equivalent to a negative replication issued from an unstructured population. Our theoretical statements are supported by numerical simulations performed on bifurcation diagrams.

scholarly journals CARACTERÍSTICAS ESTRUTURAIS E ACÚMULO DE FITOMASSA DO MILHETO SOB DIFERENTES REGIMES DE IRRIGAÇÃO COM ÁGUA RESIDUÁRIA E ADUBAÇÃO ORGÂNICA

Irriga ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 206-220
Author(s):  
Jose Raliuson Inácio Silva ◽  
Eduardo Souza ◽  
Maurício Luiz de Mello Vieira Leite ◽  
Genival Barros Júnior ◽  
José Romualdo de Sousa Lima ◽  
...  
Keyword(s):  
Temporal Dynamics ◽  
Pennisetum Glaucum ◽  
Structural Characteristics ◽  
Irrigation Management ◽  
Growth Dynamics ◽  
Structural Features ◽  
Stem Length ◽  
Control Treatment ◽  
Root Mass ◽  
Organic Fertilization

CARACTERÍSTICAS ESTRUTURAIS E ACÚMULO DE FITOMASSA DO MILHETO SOB DIFERENTES REGIMES DE IRRIGAÇÃO COM ÁGUA RESIDUÁRIA E ADUBAÇÃO ORGÂNICA     JOSÉ RALIUSON INÁCIO SILVA1; EDUARDO SOUZA1; MAURÍCIO LUIZ DE MELLO VIEIRA LEITE1; GENIVAL BARROS JUNIOR1; JOSE ROMUALDO DE SOUSA LIMA2 E ALDO TORRES SALES1   1Universidade Federal Rural de Pernambuco, Unidade Acadêmica de Serra Talhada, Programa de Pós-Graduação em Produção Vegetal, Avenida Gregório Ferraz Nogueira, s/n, José Tomé de Souza Ramos – CEP: 56909-535, Serra Talhada –PE, Brasil, [email protected], [email protected], [email protected], [email protected], [email protected] 2Universidade Federal do Agreste de Pernambuco, Avenida Bom Pastor, s/n, Boa Vista – CEP:55292-270, Granhuns-PE, [email protected]     1 RESUMO   A utilização de água residuária pode aumentar a oferta hídrica e de alimentos em regiões semiáridas. Assim, objetivou-se estudar a dinâmica temporal das características estruturais e acúmulo de fitomassa do milheto irrigado com diferentes lâminas de água cinza, com e sem adubação orgânica. A pesquisa foi conduzida em ambiente protegido em esquema fatorial (4 x 2) + 1, com três repetições, sendo os fatores: níveis de água disponível do solo (25, 50, 75 e 100%) e doses de esterco (0 e 34 Mg ha-1), mais o tratamento controle (irrigação com água potável e sem adubação). Foram realizadas avaliações semanais das características estruturais: comprimento e diâmetro do colmo e número de perfilhos, folhas totais, folhas vivas e folhas mortas, sendo ajustados modelos matemáticos para descrever o comportamento dessas características ao longo do ciclo da cultura. Após 60 dias de aplicação dos tratamentos o milheto foi colhido e determinou-se o acúmulo de fitomassa e massa de raízes. O modelo sigmoidal é o que melhor explica a dinâmica da maioria das características estruturais. A irrigação com águas cinzas não afetou as características estruturais, massa de raízes e o acúmulo de fitomassa do milheto, sendo indicado adubação a fim de melhorar o seu desempenho.   Palavras-chave: Pennisetum glaucum, águas cinzas, dinâmica do crescimento, manejo de irrigação     SILVA, J. R. I.; SOUZA, E.; LEITE, M. L. M. V.; BARROS JUNIOR, G.; LIMA, J. R. S; SALES, A. T. STRUCTURAL CHARACTERISTICS AND PHYTOMASS ACCUMULATION OF MILLET UNDER DIFFERENT IRRIGATION REGIMES WITH WASTEWATER AND ORGANIC FERTILIZATION             2 ABSTRACT   The use of wastewater can increase the water and food supply in semi-arid regions. Thus, the objective was to study the temporal dynamics of structural characteristics and the accumulation of phytomass in millet irrigated with different depths of greywater, with and without organic fertilization. The research was conducted under greenhouse conditions in a factorial scheme (4 x 2) + 1 with three replications, the factors being levels of water available from the soil (25, 50, 75 and 100%) and manure doses (0 and 34 Mg ha-1), plus control treatment (irrigation with drinking water and without fertilization). It was performed weekly evaluations of structural characteristics: stem length and diameter, and number of tillers, total leaves, live leaves and dead leaves. Mathematical models were adjusted to describe the behavior of these characteristics throughout the cycle. After 60 days of the application of the treatments, millet was harvested and the accumulation of phytomass and root mass was determined. The sigmoidal model best explains the dynamics of most structural features. The irrigation with greywaters did not affect the structural characteristics, root mass and phytomass accumulation of millet, and fertilization is indicated to improve its performance.   Keywords: Pennisetum glaucum, greywaters, growth dynamics, irrigation management

scholarly journals Evaluation of growth and flowering of Chenopodium quinoa Willd. under Polish conditions

2012 ◽  
Vol 59 (1) ◽  
pp. 487-496 ◽  
Author(s):  
Krzysztof Gęsiński
Keyword(s):  
Nutritive Value ◽  
Chenopodium Quinoa ◽  
Growth Dynamics ◽  
Parent Material ◽  
South American ◽  
Flowering Stage ◽  
Seed Formation ◽  
Continuous Growth ◽  
Development Models ◽  
Long Period

The material presented refers to the estimation of growth and the flowering (<i>Chenopodium quinoa</i> Willd.) under Polish conditions. The species has been a South-American pseudocereal cultivated in the traditional form in the Andean region for over 5 thousand years. Its advantage, apart from low soil and climate requirements, is that it shows high nutritive value. The <i>Chenopodium quinoa</i> protein is especially valuable with its amino acid composition which is better balanced than that of wheat or maize. It shows a better share of egzogenic aminoacids. Field examinations were carried out in 1999-2001 at the Experiment Station of Cultivar Testing at Chrząstowo. The experiment involved two cultivars from two various growing regions: America and Europe. Analyses were made to include development stages, plant growth dynamics, inflorescences development dynamics, inflorescence habit and flowering. Differences were recorded in the growth and development models of the cultivars researched. The European cultivar had a short compact inflorescence with a short flowering period, reaching 120 cm. American cultivar plants were high (160 cm); they showed a slower continuous growth, loose big-in-size inflorescence, and a long period of flowering. The plants ended their growing season over the flowering stage or seed formation. The adequate growth, the course of flowering and, as a result, a stable yielding of the European cultivar make the group suitable for the cultivation under Polish conditions. This breeding group should also be the parent material for the cultivation of the Polish cultivar of <i>Chenopodium quinoa</i>.

scholarly journals Temporal dynamics of cardiac hypertrophic growth in response to pressure overload

2017 ◽  
Vol 313 (6) ◽  
pp. H1119-H1129 ◽  
Author(s):  
Yuan Wang ◽  
Yuannyu Zhang ◽  
Guanqiao Ding ◽  
Herman I. May ◽  
Jian Xu ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Cardiac Myocytes ◽  
Temporal Dynamics ◽  
Pressure Overload ◽  
Growth Dynamics ◽  
Neonatal Rat ◽  
Synthesis Rate ◽  
Protein Synthesis Rate ◽  
Hypertrophic Growth

Hypertension is one of the most important risk factors of heart failure. In response to high blood pressure, the left ventricle manifests hypertrophic growth to ameliorate wall stress, which may progress into decompensation and trigger pathological cardiac remodeling. Despite the clinical importance, the temporal dynamics of pathological cardiac growth remain elusive. Here, we took advantage of the puromycin labeling approach to measure the relative rates of protein synthesis as a way to delineate the temporal regulation of cardiac hypertrophic growth. We first identified the optimal treatment conditions for puromycin in neonatal rat ventricular myocyte culture. We went on to demonstrate that myocyte growth reached its peak rate after 8–10 h of growth stimulation. At the in vivo level, with the use of an acute surgical model of pressure-overload stress, we observed the maximal growth rate to occur at day 7 after surgery. Moreover, RNA sequencing analysis supports that the most profound transcriptomic changes occur during the early phase of hypertrophic growth. Our results therefore suggest that cardiac myocytes mount an immediate growth response in reply to pressure overload followed by a gradual return to basal levels of protein synthesis, highlighting the temporal dynamics of pathological cardiac hypertrophic growth. NEW & NOTEWORTHY We determined the optimal conditions of puromycin incorporation in cardiac myocyte culture. We took advantage of this approach to identify the growth dynamics of cardiac myocytes in vitro. We went further to discover the protein synthesis rate in vivo, which provides novel insights about cardiac temporal growth dynamics in response to pressure overload.

scholarly journals Assessment of the ecotoxicity of urban estuarine sediment using benthic and pelagic copepod bioassays

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4936 ◽  
Author(s):  
Maria P. Charry ◽  
Vaughan Keesing ◽  
Mark Costello ◽  
Louis A. Tremblay
Keyword(s):  
Dna Damage ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Sediment Contamination ◽  
Estuarine Sediments ◽  
Biological Processes ◽  
Sediment Samples ◽  
Pelagic Copepod ◽  
Polycyclic Aromatic ◽  
Receiving Environments

Urban estuarine sediments are sinks to a range of contaminants of anthropogenic origin, and a key challenge is to characterize the risk of these compounds to receiving environments. In this study, the toxicity of urban estuarine sediments was tested using acute and chronic bioassays in the benthic harpacticoid Quinquelaophonte sp., and in the planktonic calanoid Gladioferens pectinatus, two New Zealand copepod species. The sediment samples from the estuary tributary sites significantly impacted reproduction in Quinquelaophonte sp. However, results from one of the estuary sites were not significantly different to those from the tributaries sites, suggesting that chemicals other than trace metals, polycyclic aromatic hydrocarbons and ammonia may be the causative stressors. Sediment elutriate samples had significant effects on reproductive endpoints in G. pectinatus, and on the induction of DNA damage in cells, as shown by the comet assay. The results indicate that sediment contamination at the Ahuriri Estuary has the potential to impact biological processes of benthic and pelagic organisms. The approach used provides a standardized methodology to assess the toxicity of estuarine sediments.

A COMPARISON OF THE ROLES OF LOCALISED AND NONLOCALISED GROWTH FACTORS IN SOLID TUMOUR GROWTH

1999 ◽  
Vol 09 (04) ◽  
pp. 541-568 ◽  
Author(s):  
HELEN M. BYRNE
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Numerical Simulations ◽  
Tumour Cell ◽  
Solid Tumour ◽  
Tumour Growth ◽  
Growth Dynamics ◽  
Inactive Form ◽  
The Standard Model ◽  
Solid Tumour Growth

Recent experimental results suggest that during proliferation, tumour cells express growth factors that modify their growth dynamics. In this paper we extend the standard model of avascular tumour growth to study the effect that two types of growth factors (localised or nondiffusible and diffusible) can have on the tumour's development. In both cases we assume that the growth factor is produced in inactive form and becomes activated when it binds to a tumour cell. We show how the inclusion into the model of such GFs endows the tumour with history dependence, in that its evolution depends not only on its structure at a given instant but also on its structure at earlier times. We also present numerical simulations to illustrate the various ways in which the two types of growth factors affect the tumours' growth dynamics. The physical implications of the results are discussed briefly and several experiments are suggested which could be performed to validate the model hypotheses and results.

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