scholarly journals Bertalanffy-Pütter models for avian growth

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250515
Author(s):  
Norbert Brunner ◽  
Manfred Kühleitner ◽  
Katharina Renner-Martin
Keyword(s):  
Inflection Point ◽  
A Priori ◽  
Fixed Ratio ◽  
Logistic Growth ◽  
Light Pollution ◽  
Growth Curve Analysis ◽  
Growth Data ◽  
Richards Model ◽  
Lower Ratio ◽  
Blue Tits

This paper explores the ratio of the mass in the inflection point over asymptotic mass for 81 nestlings of blue tits and great tits from an urban parkland in Warsaw, Poland (growth data from literature). We computed the ratios using the Bertalanffy-Pütter model, because this model was more flexible with respect to the ratios than the traditional models. For them, there were a-priori restrictions on the possible range of the ratios. (Further, as the Bertalanffy-Pütter model generalizes the traditional models, its fit to the data was necessarily better.) For six birds there was no inflection point (we set the ratio to 0), for 19 birds the ratio was between 0 and 0.368 (lowest ratio attainable for the Richards model), for 48 birds it was above 0.5 (fixed ratio of logistic growth), and for the remaining eight birds it was in between; the maximal observed ratio was 0.835. With these ratios we were able to detect small variations in avian growth due to slight differences in the environment: Our results indicate that blue tits grew more slowly (had a lower ratio) in the presence of light pollution and modified impervious substrate, a finding that would not have been possible had we used traditional growth curve analysis.

Modelling of growth alteration in Japanese quail after a selection experiment for body weight at 4 weeks of age

2018 ◽  
Vol 156 (9) ◽  
pp. 1153-1159
Author(s):  
G. Abou Khadiga ◽  
B. Y. F. Mahmoud ◽  
E. A. El-Full
Keyword(s):  
Body Weight ◽  
Japanese Quail ◽  
Inflection Point ◽  
Mixed Model ◽  
Gompertz Model ◽  
Information Criterion ◽  
Control Line ◽  
Growth Data ◽  
Mixed Model Approach ◽  
Richards Model

AbstractThe current study investigated the influence of selection for body weight (BW) on growth curve parameters in two lines of Japanese quail through a mixed model approach. Live BWs of 1400 Japanese quail were recorded at 3-day intervals from hatching to 42 days of age. Birds were distributed equally across lines (selected and control) and sexes (male and female). The asymptotic weight parameter (β0) values were always higher in Gompertz than Richards models in both lines. The values ofβ0were higher in the selected than control lines and in females than males across models. Differences were found in the inflection point for age and weight across lines and sexes. Values of the growth rate parameter (β2) ranged from 0.06 to 0.10 in both models, favouring males over females in both lines. Lower weights at the inflection point of both models were observed in the control line. Determination coefficient (R2) of both models in different genetic groups and sexes was similar. Mean square error (MSE) values of the Gompertz model were lower for females in selectedv.control lines. In contrast, MSE values of the Richards model were lower for selected malesv.control males. According to the criteria of choice (highestR2and lowest MSE, Akaike information criterion and Bayesian information criterion), the Richards model was considered the best fitting model for the growth data of males, while the Gompertz model was the best for growth data of female quails in both lines.

scholarly journals Multi-model forecasts of the ongoing Ebola epidemic in the Democratic Republic of Congo, March–October 2019

2020 ◽  
Vol 17 (169) ◽  
pp. 20200447
Author(s):  
Kimberlyn Roosa ◽  
Amna Tariq ◽  
Ping Yan ◽  
James M. Hyman ◽  
Gerardo Chowell
Keyword(s):  
Real Time ◽  
Dynamic Models ◽  
Democratic Republic ◽  
Democratic Republic Of Congo ◽  
Epidemiological Data ◽  
World Health ◽  
Logistic Growth ◽  
Richards Model ◽  
Wide Range ◽  
Model Approach

The 2018–2020 Ebola outbreak in the Democratic Republic of the Congo is the first to occur in an armed conflict zone. The resulting impact on population movement, treatment centres and surveillance has created an unprecedented challenge for real-time epidemic forecasting. Most standard mathematical models cannot capture the observed incidence trajectory when it deviates from a traditional epidemic logistic curve. We fit seven dynamic models of increasing complexity to the incidence data published in the World Health Organization Situation Reports, after adjusting for reporting delays. These models include a simple logistic model, a Richards model, an endemic Richards model, a double logistic growth model, a multi-model approach and two sub-epidemic models. We analyse model fit to the data and compare real-time forecasts throughout the ongoing epidemic across 29 weeks from 11 March to 23 September 2019. We observe that the modest extensions presented allow for capturing a wide range of epidemic behaviour. The multi-model approach yields the most reliable forecasts on average for this application, and the presented extensions improve model flexibility and forecasting accuracy, even in the context of limited epidemiological data.

Stochastic resonance induced by a multiplicative periodic signal in a logistic growth model with correlated noises

Open Physics ◽  
2009 ◽  
Vol 7 (3) ◽  
Author(s):  
Chunyan Bai ◽  
Luchun Du ◽  
Dongcheng Mei
Keyword(s):  
Stochastic Resonance ◽  
Growth Model ◽  
Noise Intensity ◽  
Critical Phenomenon ◽  
Fixed Ratio ◽  
Logistic Growth ◽  
Periodic Signal ◽  
Logistic Growth Model ◽  
Multiplicative Periodic Signal ◽  
Correlated Noises

AbstractThe stochastic resonance (SR) phenomenon induced by a multiplicative periodic signal in a logistic growth model with correlated noises is studied by using the theory of signal-to-noise ratio (SNR) in the adiabatic limit. The expressions of the SNR are obtained. The effects of multiplicative noise intensity α and additive noise intensity D, and correlated intensity λ on the SNR are discussed respectively. It is found that the existence of a maximum in the SNR is the identifying characteristic of the SR phenomena. In comparison with the SR induced by additive periodic signal, some new features are found: (1) When SNR as a function of λ for fixed ratio of α and D, the varying of α can induce a stochastic multi-resonance, and can induce a re-entrant transition of the peaks in SNR vs λ; (2) There exhibits a doubly critical phenomenon for SNR vs D and λ, i.e., the increasing of D (or λ) can induce the critical phenomenon for SNR with respect to λ (or D); (3) The doubly stochastic resonance effect appears when α and D are simultaneously varying in SNR, i.e., the increment of one noise intensity can help the SR on another noise intensity come forth.

scholarly journals Growth of the Bacteriocin-ProducingLactobacillus sakei Strain CTC 494 in MRS Broth Is Strongly Reduced Due to Nutrient Exhaustion: a Nutrient Depletion Model for the Growth of Lactic Acid Bacteria

2001 ◽  
Vol 67 (10) ◽  
pp. 4407-4413 ◽  
Author(s):  
Frédéric Leroy ◽  
Luc De Vuyst
Keyword(s):  
Lactic Acid ◽  
Growth Inhibition ◽  
Lactic Acid Production ◽  
Bacteriocin Production ◽  
Logistic Growth ◽  
Growth Equation ◽  
Nutrient Depletion ◽  
Growth Data ◽  
Set Up ◽  
Mrs Broth

ABSTRACT Although commercial MRS broth has been designed to allow excellent growth of lactobacilli, most of these bacteria are still subjected to a self-inhibiting process. The most likely explanation is the accumulation of lactic acid or other toxic end products and the depletion of nutrients. In this study, the self-inhibition ofLactobacillus sakei CTC 494 was analyzed in a kinetic way, and a nutrient depletion model was set up to describe the growth inhibition process. This simple model has considerable advantages compared to commonly used descriptive models such as the logistic growth equation. It offers a better fit and a more realistic description of the growth data by taking into account both growth inhibition due to lactic acid production and changes in growth rates due to nutrient depletion. Depending on the fermentation conditions, in MRS broth there appears to be a strong decrease of the specific growth rate over time. Some undefined compounds present in the complex nitrogen source of MRS broth appear to be of crucial importance because of their limited availability. Moreover, nutrient availability affects bacteriocin production through its effect on cell growth as well as on the bacteriocin production per cell. A plateau value for the bacteriocin production by L. sakei CTC 494 was observed.

scholarly journals Chlorella vulgaris logistic growth kinetics model in high concentrations of aqueous ammonia

2018 ◽  
Vol 19 (2) ◽  
pp. 1-9
Author(s):  
Azlin Suhaida Azmi ◽  
NURAIN ATIKAH CHE AZIZ ◽  
Noor Illi Mohamad Puad ◽  
Amanatuzzakiah Abdul Halim ◽  
Faridah Yusof ◽  
...  
Keyword(s):  
Chlorella Vulgaris ◽  
Aqueous Ammonia ◽  
Maximum Growth ◽  
Coefficient Of Determination ◽  
Logistic Growth ◽  
Fluorescent Light ◽  
Growth Data ◽  
Model Coefficient ◽  
Logistic Growth Model ◽  
High Concentrations

ABSTRACT: The ability of microalgae to utilize CO2 during photosynthesis and grow rapidly shows their potential in CO2 bio-fixation to capture and store the gas. However, CO2 capture by this biological approach is very slow compared to chemical reaction-based processes such as absorption using amine or aqueous ammonia. Integration between chemical (aqueous ammonia) and biological (microalgae) aspects might enhance the capturing process and at the same time the microalgae can assimilate CO2 for beneficial bioproduct formation. Thus, it is important to assess the growth of the microalgae in various concentrations of ammonia with CO2 supply. Hence, the main objective of this study is to investigate Chlorella vulgaris growth and its kinetics in aqueous ammonia. To achieve that, C. vulgaris was cultivated in various concentrations of aqueous ammonia between 0 to 1920 mg/L at room temperature (i.e. 27 °C) and supplied with 15% (v/v) of CO2 under illumination of 3500 lux of white fluorescent light. Result shows that the maximum growth capacity (Xmax) of C. vulgaris is deteriorating from 1.820 Au to 0.245 Au as the concentration of aqueous ammonia increased. However, no significant change in maximum specific growth rate (µmax) was observed. The growth data was then fitted into the logistic growth model. The model coefficient of determination (R2) is decreasing, which suggests modification of the model is required. ABSTRAK: Keupayaan alga-mikro untuk menggunakan CO2 semasa proses fotosintesis dan pembiakannya yang pesat menunjukkan potensi dalam penggunaan dan penyimpanan gas ketetapan-biologi. Walau bagaimanapun, penggunaan CO2  melalui cara ini adalah sangat perlahan berbanding proses tindak balas kimia melalui penyerapan amina ataupun cecair  ammonia. Percampuran antara tindak balas kimia (cecair ammonia) dan tindak balas biologi, memungkinkan penambahan proses percampuran dan pada masa sama alga-mikro akan menyerap CO2 bagi kepentingan pembentukan hasil biologi. Dengan itu, adalah sangat penting untuk mengawasi pertumbuhan alga-mikro dalam pelbagai ketumpatan ammonia bersama kandungan CO2. Oleh itu, objektif utama penyelidikan ini adalah untuk menyiasat pertumbuhan Chlorella vulgaris dan proses kinetik dalam cecair ammonia. Bagi memperoleh hasil tersebut,  C. vulgaris telah dikulturkan pada ketumpatan cecair berbeza antara 0 ke 1920 mg/L pada suhu bilik (iaitu 27 °C) dan dibekalkan dengan 15% (v/v) CO2 di bawah cahaya putih flurosen  3500 lux. Keputusan menunjukkan kapasiti pertumbuhan terbanyak (Xmax) C. vulgaris telah berkurang daripada 1.820 Au kepada 0.245 Au apabila ketumpatan cecair ammonia dikurangkan. Walau bagaimanapun, tiada perubahan ketara pada kadar pertumbuhan (µmax) dapat dilihat. Data kadar pertumbuhan kemudiannya dikemas kini pada model pertumbuhan logistik. Model pekali penentu (R2) telah direndahkan di mana cadangan untuk mengubah model adalah diperlukan.

Review of Thrust Prediction Method Based on Momentum Balance for Ducted Propellers and Waterjets

2005 ◽  
Author(s):  
Norbert Bulten ◽  
Bart van Esch
Keyword(s):  
Method Development ◽  
A Priori ◽  
Fixed Ratio ◽  
Prediction Method ◽  
Operating Conditions ◽  
Momentum Balance ◽  
Propulsion Systems ◽  
Ducted Propeller ◽  
Propulsion Unit ◽  
Ducted Propellers

Equations for thrust calculation of ducted propellers and waterjet propulsion systems are derived from the theory of open propellers. The streamtube of an open propeller shows contraction upstream and downstream of the propeller, with a strength depending on the propeller loading. The contraction of the streamtube in a waterjet propulsion unit is governed by the geometry of the installation. This paper presents the analyses of the development of the streamtube of a waterjet and a ducted propeller. Determination and visualization of the streamtubes is accomplished with a commercial CFD method. Development of the streamtube is analyzed in streamwise direction and as a function of the loading of the waterjet or the ducted propeller. It is proven that the ducted propeller has a fixed ratio between the velocity through the nozzle and the velocity downstream. This is comparable to the behavior of a waterjet, and consequently different from an open propeller. Thrust of the propulsion unit can be determined from a direct summation of all wall forces or from summation of the different terms of a momentum balance. The pressure, which acts on the streamtube surface, is neglected in this calculation, according to generally accepted theory. Comparison of both methods shows deviations for some operating conditions, which is attributed to the neglect of the pressure forces. It is concluded that the pressure forces on the streamtube of both ducted propellers and waterjet propulsion systems should not be neglected a priori.

scholarly journals Comparison of Non Linear Models and Artificial Neural Network to Describe the Liveweight from Birth to Maturity in Female Jersey Cattle

2021 ◽  
pp. 114-119
Author(s):  
D. O. Omoniwa ◽  
J. E. T. Akinsola ◽  
R. O. Okeke ◽  
J. M. Madu ◽  
D. S. Bunjah Umar
Keyword(s):  
Neural Network ◽  
Goodness Of Fit ◽  
Inflection Point ◽  
Linear Models ◽  
Network Models ◽  
Linear Functions ◽  
Growth Data ◽  
Neural Network Models ◽  
Jersey Cattle ◽  
Non Linear

Evaluation of growth data is an important strategy to manage gross feed requirement in female Jersey cattle in the New Derived Guinea Savannah Zone of Nigeria. Two non-linear functions (Gompertz and Logistic) and Neural network models were used to fit liveweight (LW)-age data using the non linear procedure of JMP statistical software. Data used for this study were collected from 150 Jersey female cattle in Shonga Dairy Farm, Kwara, State from 2010-2018. The Neural network function showedthe best goodness of fit. Both the Gompertz and Logistic functions overestimated LW at birth, 3, 36, 48, 60 and 72months respectively. NN function overestimated the LW at 0, 3, 24, 36 and 72 months. The Gompertzfunction had the best estimation of asymptotic weight (649.51 kg) with average absolute growth rate (0.061 kg/day).The inflection point was 15.95, 9.55 and 34.5 months in Logistic, Gompertz and neural network models, respectively. A strong and positive correlation was observed between asymptote and inflection point in Gompertz functions. The metrics of goodness of fit criteria (R2 and RMSE), showed that NN with multilayer perceptron was superior to the other models but Gompertz model, was best in its ability to approximate complex functions of growth curve parametersin female Jersey cattle.

GROWTH EFFICIENCY IN MICE SELECTED FOR INCREASED BODY WEIGHT

1990 ◽  
Vol 70 (2) ◽  
pp. 371-381 ◽  
Author(s):  
R. KEITH SALMON ◽  
DAVID R. C. BAILEY ◽  
RAY WEINGARDT ◽  
ROY T. BERG
Keyword(s):  
Body Weight ◽  
High Growth ◽  
Growth Efficiency ◽  
Feed Consumption ◽  
Logistic Growth ◽  
Growth Curve Analysis ◽  
Previous Suggestion ◽  
Growth Selection ◽  
Selection For ◽  
Degree Of Maturity

To elucidate the effect of selection for increased growth upon growth efficiency (gain:feed), growth and feed consumption patterns were studied in three lines of mice. Two of the mouse lines (H lines) had been selected for high 42-d body weight while the third was an unselected foundation (FP) population. The two H lines differed in population size and were designated as the high-large (HL) and high-small (HS) lines. Logistic growth curve analysis revealed that, in terms of growth rate and mature body size, the three lines could be ranked as HL > HS > FP. When considered relative to age, the feed consumption of the H line mice exceeded that of FP mice. When growth efficiency was considered relative to body weight, HL mice exhibited a significantly higher efficiency than either HS or FP mice. However, when considered relative to degree of maturity (body weight/asymptotic body weight), differences in growth efficiency were greatly reduced. This effect of maturity upon growth efficiency is compatible with the previous suggestion (Taylor and Murray 1987) that many growth-related variables are strongly associated with an animal's "target" mature body weight. A corollary of this suggestion is that much of the well characterized selection responses, of "high-growth" selection lines, may be accounted for by genetic differences in a factor associated with the elevation of their target mature body weight. Key words: Growth-selected mice, growth efficiency, mature body weight

Food and Growth of Fishes.: I. A Growth Curve Derived from Experimental Data

1965 ◽  
Vol 22 (2) ◽  
pp. 521-542 ◽  
Author(s):  
J. E. Paloheimo ◽  
L. M. Dickie
Keyword(s):  
Growth Phase ◽  
Laboratory Experiments ◽  
Inflection Point ◽  
Growth Efficiency ◽  
Von Bertalanffy ◽  
Biological Productivity ◽  
Growth Data ◽  
Average Size ◽  
Growth Experiments

A general equation for growth of fishes is obtained through use of the relations among body weight, metabolic rate, and growth efficiency that have been found in laboratory experiments. The curves show an early inflection point and gradually decreasing growth rate thereafter, without a theoretical asymptote. When growth efficiency is constant this equation indicates that growth becomes nearly exponential and is fitted exactly by the Parker and Larkin (1959) equation. When growth efficiency decreases with increasing rations the curves become more complex, as described here.Growth curves having an asymptote, such as the von Bertalanffy curve, have often been fitted to growth data. When the estimated asymptote can be related to the inflection point of the early part of a growth phase, it is proportional to a physiological time scale suggested by the food–growth relations. Truly asymptotic growth would appear to result only from complex changes in metabolism, growth efficiency, or interactions with mortality of the sort suggested by Lee's phenomenon.Some consequences of these results of food–growth experiments are discussed in relation to studies of biological productivity, especially their bearing on objectives of fisheries management. They suggest that, in general, highest sustained yield from a particular growth phase or stanza is obtained from a type of cropping which results in a population of fish having an average size near that of the smallest fish in the stanza.

Growth curve analysis of birds: the Richards model and procedural problems

1984 ◽  
Vol 62 (12) ◽  
pp. 2429-2435 ◽  
Author(s):  
Reto Zach ◽  
Yakov Liner ◽  
Gerald L. Rigby ◽  
Keith R. Mayoh
Keyword(s):  
Body Mass ◽  
Growth Curve ◽  
Selection Criterion ◽  
Curve Analysis ◽  
Model Parameters ◽  
Growth Curve Analysis ◽  
Primary Feather ◽  
Richards Model ◽  
Special Cases ◽  
Residual Variances

Four sigmoid growth curve models for birds were compared using the daily body masses and primary-feather lengths of 35 nestling tree swallows (Tachycineta bicolor). The Richards model was superior to the von Bertalanffy, Gompertz, and logistic models for body mass, but not for primary-feather length. The latter models have fixed growth forms and are special cases of the flexible Richards model. Owing to parameter correlations, the Richards model was very sensitive to the starting parameter values for the numerical computer fitting routines. The lack of data leading up to the asymptote made it difficult to calculate good starting values for primary-feather length. None of the models tested was completely satisfactory for primary-feather length, as indicated by nonrandomly distributed residuals over time. The log transformation was appropriate for body mass. It homogenized the residual variances and increased the explained percentage of variation. The explained percentage of variation was a useful selection criterion for the best-fitting model, especially since it was directly related to randomness in the distribution of the residuals and homogeneity of residual variances. However, even percentages of variation exceeding 99.5%, did not necessarily indicate an excellent fit. The Richards model did not yield more model parameters for growth curve analysis, because the shape parameter and the growth rate constant were almost perfectly correlated.

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