scholarly journals A New Flexible Sigmoidal Growth Model

Symmetry ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 204 ◽  
Author(s):  
Liying Cao ◽  
Pei-Jian Shi ◽  
Lin Li ◽  
Guifen Chen
Keyword(s):  
Growth Rate ◽  
Growth Model ◽  
Growth Models ◽  
Differential Evolution Algorithm ◽  
Growth Patterns ◽  
Growth Data ◽  
Ecological Processes ◽  
Maximum Biomass ◽  
Sigmoidal Growth ◽  
Growth Of Animals

Biological growth is driven by numerous functions, such as hormones and mineral nutrients, and is also involved in various ecological processes. Therefore, it is necessary to accurately capture the growth trajectory of various species in ecosystems. A new sigmoidal growth (NSG) model is presented here for describing the growth of animals and plants when the assumption is that the growth rate curve is asymmetric. The NSG model was compared with four classic sigmoidal growth models, including the logistic equation, Richards, Gompertz, and ontogenetic growth models. Results indicated that all models fit well with the empirical growth data of 12 species, except the ontogenetic growth model, which only captures the growth of animals. The estimated maximum asymptotic biomass wmax of plants from the ontogenetic growth model was not reliable. The experiment result shows that the NSG model can more precisely estimate the value and time of reaching maximum biomass when growth rate becomes close to zero near the end of growth. The NSG model contains three other parameters besides the value and time of reaching maximum biomass, and thereby, it can be difficult to assign initial values for parameterization using local optimization methods (e.g., using Gauss–Newton or Levenberg–Marquardt methods). We demonstrate the use of a differential evolution algorithm for resolving this issue efficiently. As such, the NSG model can be applied to describing the growth patterns of a variety of species and estimating the value and time of achieving maximum biomass simultaneously.

Age and growth estimates of the jumbo flying squid (Dosidicus gigas) off Peru

2019 ◽  
Vol 32 ◽  
pp. 7
Author(s):  
Carlos Goicochea-Vigo ◽  
Enrique Morales-Bojórquez ◽  
Viridiana Y. Zepeda-Benitez ◽  
José Ángel Hidalgo-de-la-Toba ◽  
Hugo Aguirre-Villaseñor ◽  
...  
Keyword(s):  
Growth Model ◽  
Growth Pattern ◽  
Growth Models ◽  
Information Criterion ◽  
Growth Patterns ◽  
Age And Growth ◽  
Dosidicus Gigas ◽  
Asymptotic Growth ◽  
Schnute Model ◽  
Gompertz Growth Model

Mantle length (ML) and age data were analyzed to describe the growth patterns of the flying jumbo squid, Dosidicus gigas, in Peruvian waters. Six non-asymptotic growth models and four asymptotic growth models were fitted. Length-at-age data for males and females were analysed separately to assess the growth pattern. Multi-model inference and Akaike's information criterion were used to identify the best fitting model. For females, the best candidate growth model was the Schnute model with L∞ = 106.96 cm ML (CI 101.23–110.27 cm ML, P < 0.05), age at growth inflection 244.71 days (CI 232.82–284.86 days, P < 0.05), and length at growth inflection 57.26 cm ML (CI 55.42–58.51 cm ML, P < 0.05). The growth pattern in males was best described by a Gompertz growth model with L∞ = 127.58 cm ML (CI 115.27–131.80 cm ML, P < 0.05), t0 = 21.8 (CI 20.06–22.41, P < 0.05), and k = 0.007 (CI 0.006–0.007, P < 0.05). These results contrast with the growth model previously reported for D. gigas in the region, where the growth pattern was identified as non-asymptotic.

Growth and sexual size dimorphism in Alberta populations of the eastern short-horned lizard, Phrynosoma douglassi brevirostre

1985 ◽  
Vol 63 (1) ◽  
pp. 139-154 ◽  
Author(s):  
G. Lawrence Powell ◽  
Anthony P. Russell
Keyword(s):  
Growth Model ◽  
Sexual Difference ◽  
Sexual Size Dimorphism ◽  
Growth Models ◽  
Tail Length ◽  
Growth Patterns ◽  
Head Width ◽  
Adult Size ◽  
Adult Males ◽  
Size Dimorphism

Alberta populations of Phrynosoma douglassi brevirostre display marked sexual size dimorphism, adult females being considerably larger than adult males. Discriminant analyses of whole mensural characters and of scaled mensural characters indicate that this dimorphism is present from birth, although it is more strongly expressed after sexual maturity. Recapture data were used to generate modified logistic by weight growth models for snout–vent length (SVL), and allometric models for each sex were generated for growth in tail length, head length, and head width. The SVL growth model for females indicates delayed maturity leading to greater adult size, an expected feature of a female viviparine. The SVL growth model for males indicates that growth ceases sooner than in females, resulting in a smaller adult size. This is possibly a result of male dispersal competition, an hypothesis further borne out by the results of a preliminary analysis of mobility in the two sexes, and may also be influenced by intersexual dietary competition. Differences in head dimensions between the sexes are a function of the differences in SVL at adulthood, but there is a significant sexual difference in the allometric relationship of tail length to SVL. No difference in the growth patterns and adult size of either sex was found to exist over the range in Alberta.

Two-year tree growth patterns investigated from monthly girth records using dendrometer bands in a wet evergreen forest in India

2000 ◽  
Vol 16 (3) ◽  
pp. 429-446 ◽  
Author(s):  
Raphaël Pélissier ◽  
Jean-pierre Pascal
Keyword(s):  
Growth Rate ◽  
Tree Growth ◽  
Growth Patterns ◽  
Annual Growth ◽  
Evergreen Forest ◽  
Annual Growth Rate ◽  
Growth Data ◽  
Growth Profiles ◽  
Dendrometer Bands ◽  
The Mean

With the aim of characterizing tree growth patterns, this paper re-examines the growth data of 100 selected trees belonging to 24 species that were recorded monthly in a 0.2-ha plot of a wet evergreen forest in the Western Ghats of India during the period 1980–82 using dendrometer bands. The mean growth profile, combining all of the selected trees, showed: (a) a significantly lower annual growth rate during the second year of survey which seemed to be negatively related to monsoon precipitation; (b) significant intra-annual growth variation clearly related to the regular alternation between a period of heavy rain and a quite long dry season of the monsoon climatic regime. Analysis of the variability of the individual smoothed growth profiles representing the 2-y trend of the growth data showed that: (a) the mean growth rate depended on a combination of an intrinsic endogenous variable (the structural class grouping species according to their maximum size), a tree size variable (tree diameter at breast height, dbh) and a neighbourhood variable (the number of taller neighbours in a 10-m radius); (b) the sudden change in growth rate from one year to the other was not predictable using these variables. The amplitude of the seasonal variations, investigated from the detrended growth profiles, appeared to be dependent on a combination of tree dbh and the number of taller neighbours in a 10-m radius. A co-inertia analysis of the smoothed and the detrended growth profiles indicated that the trees with fast growth also exhibited high seasonal variation. It is suggested that fast growing trees are those with favourable crown positions, which are consequently subject to high transpiration rates due to radiation and wind exposure.

scholarly journals The influence of sample distribution on growth model output for a highly-exploited marine fish, the Gulf Corvina (Cynoscion othonopterus)

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5582 ◽  
Author(s):  
Derek G. Bolser ◽  
Arnaud Grüss ◽  
Mark A. Lopez ◽  
Erin M. Reed ◽  
Ismael Mascareñas-Osorio ◽  
...  
Keyword(s):  
Growth Model ◽  
Marine Fish ◽  
Growth Models ◽  
Growth Patterns ◽  
Von Bertalanffy ◽  
Model Output ◽  
Age Classes ◽  
Equal Distribution ◽  
Sample Distribution ◽  
Richards Model

Estimating the growth of fishes is critical to understanding their life history and conducting fisheries assessments. It is imperative to sufficiently sample each size and age class of fishes to construct models that accurately reflect biological growth patterns, but this may be a challenging endeavor for highly-exploited species in which older fish are rare. Here, we use the Gulf Corvina (Cynoscion othonopterus), a vulnerable marine fish that has been persistently overfished for two decades, as a model species to compare the performance of several growth models. We fit the von Bertalanffy, Gompertz, logistic, Schnute, and Schnute–Richards growth models to length-at-age data by nonlinear least squares regression and used simple indicators to reveal biased data and ensure our results were biologically feasible. We then explored the consequences of selecting a biased growth model with a per-recruit model that estimated female spawning-stock-biomass-per-recruit and yield-per-recruit. Based on statistics alone, we found that the Schnute–Richards model described our data best. However, it was evident that our data were biased by a bimodal distribution of samples and underrepresentation of large, old individuals, and we found the Schnute–Richards model output to be biologically implausible. By simulating an equal distribution of samples across all age classes, we found that sample distribution distinctly influenced model output for all growth models tested. Consequently, we determined that the growth pattern of the Gulf Corvina was best described by the von Bertalanffy growth model, which was the most robust to biased data, comparable across studies, and statistically comparable to the Schnute–Richards model. Growth model selection had important consequences for assessment, as the per-recruit model employing the Schnute–Richards model fit to raw data predicted the stock to be in a much healthier state than per-recruit models employing other growth models. Our results serve as a reminder of the importance of complete sampling of all size and age classes when possible and transparent identification of biased data when complete sampling is not possible.

scholarly journals Growth Patterns of birds, dinosaurs and reptiles: Are differences real or apparent?

2019 ◽  
Author(s):  
Norbert Brunner ◽  
Manfred Kühleitner ◽  
Werner-Georg Nowak ◽  
Katharina Renner-Martin ◽  
Klaus Scheicher
Keyword(s):  
Differential Equation ◽  
Growth Pattern ◽  
Broiler Chicken ◽  
Growth Models ◽  
Growth Patterns ◽  
Von Bertalanffy ◽  
Growth Data ◽  
Quantitative Studies ◽  
Best Fitting

AbstractSystematics of animals was done on their appearance or genetics. One can also ask about similarities or differences in the growth pattern. Quantitative studies of the growth of dinosaurs have made possible comparisons with modern animals, such as the discovery that dinosaurs grew in relation to their size faster than modern reptiles. However, these studies relied on only a few growth models. If these models are false, what about the conclusions? This paper fits growth data to a more comprehensive class of models, defined by the von Bertalanffy-Pütter differential equation. Applied to data about dinosaurs, reptiles and birds, the best fitting models confirmed that dinosaurs may have grown faster than alligators. However, compared to modern broiler chicken, this difference was small.

scholarly journals Growth and Variability of Major Food Crops Production in Khyber Pakhtunkhwa, Pakistan

2017 ◽  
Vol 2 (1) ◽  
pp. 6
Author(s):  
Syed Asghar Ali Shah ◽  
Alamgir Khalil Khalil
Keyword(s):  
Growth Rate ◽  
Growth Model ◽  
Crop Production ◽  
Growth Models ◽  
Secondary Data ◽  
Food Crops ◽  
Food Crop ◽  
Khyber Pakhtunkhwa ◽  
Major Food ◽  
Food Crop Production

The present study was undertaken to investigate the growth and variability in major food crops production of Khyber Pakhtunkhwa. The study was based on secondary data, covers a period of about 30 years i.e. starting from 1984-85 to 2013-14, Whereas, the growth models has been employed to fit the best growth model and Cuddy Della Vella Index was applied to find variability in major food crops production i.e. wheat, maize, sugarcane and rice. Based on the results of analyzed data, it was found that in major food crops (wheat, maize, sugarcane, rice) Production, the growth models i.e.  Cubic growth model, power growth model, cubic growth model, cubic growth model respectively were found suitable, based on the R2 criteria and fitted trend line. After selecting best fitted model for each major food crop, the growth rate was calculated by using the selected fitted models which were found to be 10.97%, 8.00%, 45.31% and 1.19% respectively.  Moreover, the variability for each major food crop production was found to be 1.53%, 1.23%, 0.44% and 0.79% respectively. 

scholarly journals Testing mechanistic models of growth in insects

2015 ◽  
Vol 282 (1819) ◽  
pp. 20151973 ◽  
Author(s):  
James L. Maino ◽  
Michael R. Kearney
Keyword(s):  
Energy Density ◽  
Growth Model ◽  
Reproductive Output ◽  
Production Efficiency ◽  
Predictive Power ◽  
Growth Models ◽  
Mechanistic Models ◽  
Energy Reserves ◽  
Growth Data ◽  
Large Numbers

Insects are typified by their small size, large numbers, impressive reproductive output and rapid growth. However, insect growth is not simply rapid; rather, insects follow a qualitatively distinct trajectory to many other animals. Here we present a mechanistic growth model for insects and show that increasing specific assimilation during the growth phase can explain the near-exponential growth trajectory of insects. The presented model is tested against growth data on 50 insects, and compared against other mechanistic growth models. Unlike the other mechanistic models, our growth model predicts energy reserves per biomass to increase with age, which implies a higher production efficiency and energy density of biomass in later instars. These predictions are tested against data compiled from the literature whereby it is confirmed that insects increase their production efficiency (by 24 percentage points) and energy density (by 4 J mg −1 ) between hatching and the attainment of full size. The model suggests that insects achieve greater production efficiencies and enhanced growth rates by increasing specific assimilation and increasing energy reserves per biomass, which are less costly to maintain than structural biomass. Our findings illustrate how the explanatory and predictive power of mechanistic growth models comes from their grounding in underlying biological processes.

Describing and predicting potential growth in the pig

2004 ◽  
Vol 78 (3) ◽  
pp. 379-388 ◽  
Author(s):  
I. J. Wellock ◽  
G. C. Emmans ◽  
I. Kyriazakis
Keyword(s):  
Growth Rate ◽  
Goodness Of Fit ◽  
Growth Models ◽  
Growth Function ◽  
Logistic Function ◽  
Growth Data ◽  
Gompertz Function ◽  
Potential Growth ◽  
Nutritional Conditions ◽  
Wide Range

AbstractMost animal growth models contain an explicit growth function. It determines the pattern of growth over the lifetime of the animal and defines an upper limit to growth rate (the potential). The criterion of the ‘goodness-of-fit’ to one or more sets of data is frequently used to select a suitable growth function. Alternative criteria are described here that can be used to choose between forms that describe potential growth. Of the functions reviewed only a few fulfilled all of the proposed criteria. Of these the Logistic and Gompertz functions were favoured because of an economy of parameters and their ability to describe relative growth rate as a simple function of size. The Logistic function was rejected on the grounds of its numerical consequences for growth in pigs over a wide range of degrees of maturity, leaving the Gompertz function to be tested for its ability to make sensible predictions of potential growth. Pre-natal growth data, assumed to occur under non-limiting conditions as long as the mother is not subjected to extremely adverse nutritional conditions or incidence of infection, were used to estimate the values of the two Gompertz function parameters-the growth coefficient and the initial condition-given an estimate of mature size. The values were comparable with literature estimates based on post-natal growth and predictions of growth rate over a wide range of degree of maturity were thus sensible. On these grounds, and because it uses few parameters all with biological meaning, the Gompertz function is proposed as a suitable descriptor of potential growth.

scholarly journals Effects of cofD gene knock-out on the methanogenesis of Methanobrevibacter ruminantium

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian Ma ◽  
Xueying Wang ◽  
Ting Zhou ◽  
Rui Hu ◽  
Huawei Zou ◽  
...  
Keyword(s):  
Growth Rate ◽  
Specific Growth ◽  
Production Capacity ◽  
Maximum Amount ◽  
Logarithmic Phase ◽  
Wild Type ◽  
Knock Out ◽  
Maximum Biomass ◽  
Reproductive Ability ◽  
Methanobrevibacter Ruminantium

AbstractThis study aimed to investigate the effects of cofD gene knock-out on the synthesis of coenzyme F420 and production of methane in Methanobrevibacter ruminantium (M. ruminantium). The experiment successfully constructed a cofD gene knock-out M. ruminantium via homologous recombination technology. The results showed that the logarithmic phase of mutant M. ruminantium (12 h) was lower than the wild-type (24 h). The maximum biomass and specific growth rate of mutant M. ruminantium were significantly lower (P < 0.05) than those of wild-type, and the maximum biomass of mutant M. ruminantium was approximately half of the wild-type; meanwhile, the proliferation was reduced. The synthesis amount of coenzyme F420 of M. ruminantium was significantly decreased (P < 0.05) after the cofD gene knock-out. Moreover, the maximum amount of H2 consumed and CH4 produced by mutant were 14 and 2% of wild-type M. ruminantium respectively. In conclusion, cofD gene knock-out induced the decreased growth rate and reproductive ability of M. ruminantium. Subsequently, the synthesis of coenzyme F420 was decreased. Ultimately, the production capacity of CH4 in M. ruminantium was reduced. Our research provides evidence that cofD gene plays an indispensable role in the regulation of coenzyme F420 synthesis and CH4 production in M. ruminantium.

scholarly journals Modelling growth curves of the normal infant’s mandible: 3D measurements using computed tomography

2021 ◽  
Author(s):  
Jan Aart M. Schipper ◽  
Manouk J. S. van Lieshout ◽  
Stefan Böhringer ◽  
Bonnie L. Padwa ◽  
Simon G. F. Robben ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Growth Models ◽  
Normal Growth ◽  
Growth Patterns ◽  
Ct Scans ◽  
Mandibular Ramus ◽  
Linear Measurements ◽  
Mandibular Growth ◽  
Gonial Angle ◽  
Mandibular Body

Abstract Objectives Data on normal mandibular development in the infant is lacking though essential to understand normal growth patterns and to discriminate abnormal growth. The aim of this study was to provide normal linear measurements of the mandible using computed tomography performed in infants from 0 to 2 years of age. Material and methods 3D voxel software was used to calculate mandibular body length, mandibular ramus length, bicondylar width, bigonial width and the gonial angle. Intra- and inter-rater reliability was assessed for these measurements. They were found to be sufficient for all distances; intra-class correlation coefficients were all above 0.9. Regression analysis for growth modelling was performed. Results In this multi-centre retrospective study, 109 CT scans were found eligible that were performed for various reasons (e.g. trauma, craniosynostosis, craniofacial abscesses). Craniosynostosis patients had larger mandibular measurements compared to non-craniosynostosis patients and were therefore excluded. Fifty-one CT scans were analysed. Conclusions Analysis showed that the mandible increases more in size vertically (the mandibular ramus) than horizontally (the mandibular body). Most of the mandibular growth occurs in the first 6 months. Clinical relevance These growth models provide insight into normal mandibular development in the first 2 years of life. This reference data facilitates discrimination between normal and abnormal mandibular growth.

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