Relevant bibliographies by topics / Gompertz growth / Journal articles

Journal articles on the topic 'Gompertz growth'

To see the other types of publications on this topic, follow the link: Gompertz growth.
Author: Grafiati
Published: 10 December 2022
Last updated: 29 January 2023

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Gompertz growth.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Park, Seok-Gyu, and Sang-Un Lee. "A Software Reliability Growth Model Based on Gompertz Growth Curve." KIPS Transactions:PartD 11D, no. 7 (December 1, 2004): 1451–58. http://dx.doi.org/10.3745/kipstd.2004.11d.7.1451.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

BARDOS, D. "Probabilistic Gompertz model of irreversible growth." Bulletin of Mathematical Biology 67, no. 3 (May 2005): 529–45. http://dx.doi.org/10.1016/j.bulm.2004.08.009.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

MARUŠIĆ, M., and S. VUK-PAVLOVIĆ. "PREDICTION POWER OF MATHEMATICAL MODELS FOR TUMOR GROWTH." Journal of Biological Systems 01, no. 01 (March 1993): 69–78. http://dx.doi.org/10.1142/s0218339093000069.

Full text
Abstract:
We compared the Gompertz model, the generalized Gompertz model, the Piantadosi model, the autostimulation model and the polynomials for the power to predict growth of multicellular tumor spheroids as paradigms of the prevascular phase of tumor growth. For the comparison of models we developed a criterion that established the Gompertz model as the model with the best prediction power. The prediction power of the remaining models was ranked in declining order: the generalized Gompertz model; the mutually indistinguishable Piantadosi model and the autostimulation model; and the polynomials. The ranking of models was not affected by the applied minimization criteria of weighted least squares, unweighted least squares and fitting to logarithmically transformed data, but the prediction power was affected by these criteria. The best predictions were obtained by weighted least squares, closely followed by fitting to logarithmically transformed data. The unweighted least-squares minimization was much less applicable for prediction (and description) of growth.
APA, Harvard, Vancouver, ISO, and other styles
4

Claudia Cristina Paro de, Paz, Venturini Guilherme Costa, Contini Enio, Costa Ricardo Lopes Dias da, Lameirinha Luara Paula, and Quirino Celia Raquel. "Nonlinear models of Brazilian sheep in adjustment of growth curves." Czech Journal of Animal Science 63, No. 8 (July 29, 2018): 331–38. http://dx.doi.org/10.17221/87/2017-cjas.

Full text
Abstract:
Growth curves of the Morada Nova sheep males and females were described using nonlinear models and the relationships between body weight and thoracic circumference were evaluated. Altogether 1516 repeated measures of body weight and thoracic circumference of the Morada Nova sheep (668 males and 848 females) taken since birth till 730 days of age were used. The Brody, Richards, von Bertalanffy, Gompertz, and Logistic models have been tested. The Fisher’s test (F) was used to verify the differences (P &lt; 0.05) in growth curves between males and females. The Gompertz model presented a significant difference (P &lt; 0.001) for growth curve parameters between males (asymptotic weight (A) = 40.5 kg and maturing rate (k) = 0.0043 kg/day) and females (A = 36.44 kg and k = 0.0028 kg/day). The relationships between body weight and thoracic circumference presented R<sup>2</sup> above 0.7 and a high significance (P &lt; 0.0001) for all categories, showing that the thoracic circumference may be a good indicator of body weight. In addition, a significant effect (P &lt; 0.05) of the relationship between thoracic circumference and prediction of animal’s body weight was verified using the models of linear, quadratic, and cubic regression. Among the models studied, the Gompertz model presented the best fit and biological interpretation. Furthermore, the Gompertz model indicated the need to separate animals by sex in order to properly meet nutritional requirements and determine adequate slaughter age. Thoracic circumference can be used to predict animal body weight with a high accuracy.
APA, Harvard, Vancouver, ISO, and other styles
5

Villar Goris, N. A., A. R. Selva Castañeda, E. E. Ramirez-Torres, J. Bory Reyes, L. Randez, L. E. Bergues Cabrales, and J. I. Montijano. "Correspondence between formulations of Avrami and Gompertz equations for untreated tumor growth kinetics." Revista Mexicana de Física 66, no. 5 Sept-Oct (September 1, 2020): 632. http://dx.doi.org/10.31349/revmexfis.66.632.

Full text
Abstract:
The classical and modified equations of Kolmogorov-Johnson-Mehl-Avrami are compared with the equations of conventional Gompertz andMontijano-Bergues-Bory-Gompertz, in the frame of growth kinetics of tumors. For this, different analytical and numerical criteria are usedto demonstrate the similarity between them, in particular the distance of Hausdorff. The results show that these equations are similar fromthe mathematical point of view and the parameters of the Gompertz equation are explicitly related to those of the Avrami equation. It isconcluded that Modified Kolmogorov-Johnson-Mehl-Avrami and Montijano-Bergues-Bory-Gompertz equations can be used to describe thegrowth kinetics of unperturbed tumors.
APA, Harvard, Vancouver, ISO, and other styles
6

Gultom, Fandi Rezian Pratama, Solimun Solimun, and Nurjannah Nurjannah. "Bootstrap Resampling in Gompertz Growth Model with Levenberg–Marquardt Iteration." JTAM (Jurnal Teori dan Aplikasi Matematika) 6, no. 4 (October 7, 2022): 810. http://dx.doi.org/10.31764/jtam.v6i4.8617.

Full text
Abstract:
Soybean plants have limited growth with a planting period of 12 weeks, which causes the observed sample to be very small. A small sample of soybean plant growth observations can be bias causes in the conclusion of prediction results on soybean plant growth. The purpose this study is to apply the bootstrap resampling technique in Gompertz growth model which overcomes residual distribution with small samples, the research data was taken from soybean plant growth in four varieties with four spacing treatments, five replications and twelve weeks (long planting period). Gompertz growth model uses nonlinear least squares method in estimating parameters with Levenberg–Marquardt iteration. The value of the Gompertz model after resampling bootstrap has no significant difference. The adjusted R2 value of 0.96 is close to 1. This means that the total diversity of plant heights can be explained by the Gompertz model of 96 percent. Judging from the graph of predictions of soybean plant growth before resampling and after resampling coincide with each other it can also be seen in the initial growth values before resampling 14, 05 and 14.18, the maximum growth values are 55.13 and 55.60. Bootsrap resampling technique can overcome residual normality in the Gompertz growth model, but does not change the information in the initial data.
APA, Harvard, Vancouver, ISO, and other styles
7

Carini, Fernanda, Alberto Cargnelutti Filho, Cirineu Tolfo Bandeira, Ismael Mario Marcio Neu, Rafael Vieira Pezzini, Milena Pacheco, and Rosana Marzari Thomasi. "Growth Models for Lettuce Cultivars Growing in Spring." Journal of Agricultural Science 11, no. 6 (May 15, 2019): 147. http://dx.doi.org/10.5539/jas.v11n6p147.

Full text
Abstract:
The objectives of this study were to adjust the Gompertz and logistic models to fit the fresh and dry matters of leaves and fresh and dry matters of shoots of four lettuce cultivars and indicate the model that best describes the growth in spring. Cultivars Ceres, Gloriosa, Grandes Lagos, and Rubinela were grown in protected environment and in soilless system, in the spring of 2016 and 2017. Seven days after transplantation, fresh and dry leaf matters and fresh and dry shoot matters were weighed every four days until beginning of flowering. The Gompertz and logistic models were adjusted as a function of accumulated thermal sum. The parameters of the Gompertz and logistic models and their confidence intervals were estimated, the assumptions of the models were verified, the goodness-of-fit measures and critical points were calculated, and the parametric and intrinsic nonlinearities quantified. The logistic and Gompertz growth models fitted well to fresh and dry leaf and shoot matters of cultivars Ceres, Gloriosa, Grandes Lagos, and Rubinela, under spring conditions. The logistic model is the most suitable to describe the growth of lettuce cultivars.
APA, Harvard, Vancouver, ISO, and other styles
8

Yamano, Takuya. "Statistical Ensemble Theory of Gompertz Growth Model." Entropy 11, no. 4 (November 5, 2009): 807–19. http://dx.doi.org/10.3390/e11040807.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Lo, C. F. "Stochastic Gompertz model of tumour cell growth." Journal of Theoretical Biology 248, no. 2 (September 2007): 317–21. http://dx.doi.org/10.1016/j.jtbi.2007.04.024.

Full text
APA, Harvard, Vancouver, ISO, and other styles
10

Demichell, Romano, Graziella Pratesi, Roberto Foroni, Maria Grazia Barbagini, and Monica Tortoreto. "Relative Role of Host and tumor in the Growth Pattern of Murine and Human Neoplasms following Subcutaneous Transplantation in Mice." Tumori Journal 75, no. 5 (October 1989): 429–34. http://dx.doi.org/10.1177/030089168907500506.

Full text
Abstract:
The growth patterns of two murine and eight human tumors, bilaterally implanted into subcutaneous tissue of groups of recipient mice, were studied. A Gompertz equation was fitted to experimental data for each individual implant and the Gompertz parameters were utilized as quantitative growth characteristics. The relative roles of the tumor-implanted flank (right versus left), of the individual host and of the tumor were analyzed by the paired t-test, simple linear regression model, one-way and two-way analysis of variance. Sixty pairs of Gompertz curves were obtained in seventy animals. Heterogeneity was the main characteristic of the growth pattern in all tumors under study, with a wide variability among the Gompertz parameters. Statistical analysis of experimental data showed that only the tumor systematically influenced the growth characteristics, whereas neither the tumor-implanted flank nor the individual host played a significant role. These results have both theoretical and practical implications.
APA, Harvard, Vancouver, ISO, and other styles
11

Lewis, R. M., G. C. Emmans, G. Simm, W. S. Dingwall, and J. FitzSimons. "A description of the growth of sheep." Proceedings of the British Society of Animal Science 1998 (1998): 47. http://dx.doi.org/10.1017/s1752756200596999.

Full text
Abstract:
The idea that an animal of a given kind has, and grows to, a final or mature size is a useful one and several equations have been proposed that describe such growth to maturity (Winsor, 1932; Parks, 1982; Taylor, 1982). The Gompertz is one of these growth functions and describes in a comparatively simple, single equation the sigmoidal pattern of growth. It has 3 parameters, only 2 of which are important - mature size A and the rate parameter B. Estimates of A and B, however, are highly correlated. Considering A and B as a lumped parameter (AB) may overcome this problem. A Gompertz, or any other, growth function is not expected to describe all growth curves. When the environment (e.g., feed, housing) is non-limiting, it may provide a useful and succinct description of growth. The objectives of this study were to examine: (i) if the Gompertz equation adequately describes the growth of two genotypes of sheep under conditions designed to be non-limiting; and, (ii) if the lumped parameter AB has more desirable properties for estimation than A and B separately.
APA, Harvard, Vancouver, ISO, and other styles
12

Lewis, R. M., G. C. Emmans, G. Simm, W. S. Dingwall, and J. FitzSimons. "A description of the growth of sheep." Proceedings of the British Society of Animal Science 1998 (1998): 47. http://dx.doi.org/10.1017/s0308229600032608.

Full text
Abstract:
The idea that an animal of a given kind has, and grows to, a final or mature size is a useful one and several equations have been proposed that describe such growth to maturity (Winsor, 1932; Parks, 1982; Taylor, 1982). The Gompertz is one of these growth functions and describes in a comparatively simple, single equation the sigmoidal pattern of growth. It has 3 parameters, only 2 of which are important - mature size A and the rate parameter B. Estimates of A and B, however, are highly correlated. Considering A and B as a lumped parameter (AB) may overcome this problem. A Gompertz, or any other, growth function is not expected to describe all growth curves. When the environment (e.g., feed, housing) is non-limiting, it may provide a useful and succinct description of growth. The objectives of this study were to examine: (i) if the Gompertz equation adequately describes the growth of two genotypes of sheep under conditions designed to be non-limiting; and, (ii) if the lumped parameter AB has more desirable properties for estimation than A and B separately.
APA, Harvard, Vancouver, ISO, and other styles
13

Rocha, J. Leonel, Abdel-Kaddous Taha, and D. Fournier-Prunaret. "Dynamical Analysis and Big Bang Bifurcations of 1D and 2D Gompertz's Growth Functions." International Journal of Bifurcation and Chaos 26, no. 11 (October 2016): 1630030. http://dx.doi.org/10.1142/s0218127416300305.

Full text
Abstract:
In this paper, we study the dynamics and bifurcation properties of a three-parameter family of 1D Gompertz's growth functions, which are defined by the population size functions of the Gompertz logistic growth equation. The dynamical behavior is complex leading to a diversified bifurcation structure, leading to the big bang bifurcations of the so-called “box-within-a-box” fractal type. We provide and discuss sufficient conditions for the existence of these bifurcation cascades for 1D Gompertz's growth functions. Moreover, this work concerns the description of some bifurcation properties of a Hénon's map type embedding: a “continuous” embedding of 1D Gompertz's growth functions into a 2D diffeomorphism. More particularly, properties that characterize the big bang bifurcations are considered in relation with this coupling of two population size functions, varying the embedding parameter. The existence of communication areas of crossroad area type or swallowtails are identified for this 2D diffeomorphism.
APA, Harvard, Vancouver, ISO, and other styles
14

Araújo, Ronyere Olegário de, Cintia Righetti Marcondes, Maria Cecília Florisbal Damé, Analía del Valle Garnero, Ricardo José Gunski, Dionéia Magda Everling, and Paulo Roberto Nogara Rorato. "Classical nonlinear models to describe the growth curve for Murrah buffalo breed." Ciência Rural 42, no. 3 (March 2012): 520–25. http://dx.doi.org/10.1590/s0103-84782012000300022.

Full text
Abstract:
With the objective of to adjust nonlinear models for the growth curves for a buffaloes herd raised in floodable lands in Rio Grande do Sul state, monthly records measured from birth to two years-old of 64 males and 63 females born between 1982 and 1989 were used. The models used were: Von Bertalanffy, Brody, Gompertz and Logistic. The parameters were estimated by NLIN procedure and the criteria used to evaluate the adjustment given by the models were: asymptotic standard deviation; coefficient of determination; average absolute deviation of residues and asymptotic index. Von Bertalanffy and Brody models overestimated the male asymptotic weight (A) in 15.9 and 171.3kg, respectively, and the Gompertz and Logistic models underestimated it in 4.5 and 13.4kg, respectively. For females, the Logistic model underestimated the asymptotic weight (-2.09kg), and Gompertz, Von Bertalanffy and Brody overestimated this parameter in 8.04, 17.7, and 280.33kg, respectively. The biggest average deviation was estimated by Brody model for both sexes, characterizing the biggest index. Considering the criteria, it is recommended the Gompertz and Logistic models for adjust females and males Murrah buffaloes breed growth curves.
APA, Harvard, Vancouver, ISO, and other styles
15

Shukor, Mohd Yunus. "Bartlett and the Levene’s tests of homoscedasticity of the modified Gompertz model used in fitting of Burkholderia sp. strain Neni-11 growth on acrylamide." Bioremediation Science and Technology Research 4, no. 1 (July 31, 2016): 18–19. http://dx.doi.org/10.54987/bstr.v4i1.367.

Full text
Abstract:
Most often than not, microorganism’s growth curve is sigmoidal in characteristics. The modified Gompertz model via nonlinear regression using the least square method is one of the most popular methods to describe the growth curve. One of the assumptions of a good model is that the variance of the data must be homogenous (homoscedasticity). In this work, two statistical diagnostics; the Bartlett and the Levene’s tests was performed to a modified Gompertz model utilized to model the growth of the bacterium Burkholderia sp. strain Neni-11 on acrylamide in order to satisfy the requirement above and found that data conformed to the requirement indicating the modified Gompertz model is a robust model for modelling the bacterial growth process.
APA, Harvard, Vancouver, ISO, and other styles
16

Mellett, F. D., and J. H. Randall. "A note on the growth of body parts of the ostrich (Struthio camelus)." Animal Production 58, no. 2 (April 1994): 291–93. http://dx.doi.org/10.1017/s1357729800042612.

Full text
Abstract:
In a study of the growth of various body parts of the ostrich, only the growth of the head could be described with the Gompertz function. The growth of the ostrich head (y in g) with time (x in months) is described by the Gompertz function y = 613 exp[−ln (613/133) exp(−0·26x)]. This information could be used in the design of carcass classification systems.
APA, Harvard, Vancouver, ISO, and other styles
17

Waheed, A., M. S. Khan, S. Ali, and M. Sarwar. "Estimation of growth curve parameters in Beetal goats." Archives Animal Breeding 54, no. 3 (October 10, 2011): 287–96. http://dx.doi.org/10.5194/aab-54-287-2011.

Full text
Abstract:
Abstract. Growth data from birth to one year of age on 120 Beetal goats, 30 animals on each farm, including Livestock Experiment Station (LES) Rakh Kheirewala, LES Rakh Ghulaman, LES Alladad and LPRI Bahadurnagar, Okara, Pakistan, were recorded and analysed for estimating growth curve parameters: predicted live weight, »a«, turning point of growth, »b« and rate of growth »k« by using Brody and Gompertz mathematical functions employing non-linear regression models. Estimates of the growth curve parameters »a«, »b« and »k« were 29.1, 0.916 and 0.108 for Brody and 23.4, 1.984 and 0.258 for Gompertz functions, respectively. The corresponding values of determination coefficient and mean absolute deviation for these models were 99.8 and 99.8 percent and 0.0061 and 0.0050, respectively. Flock significantly affected parameter »b« of Brody and Gompertz models. Sex did not affect any of the parameters in both models. Type of birth was a significant source of variation for parameter »b« in the Brody model. The determination coefficient showed that both the models efficiently explained the growth of Beetal kids.
APA, Harvard, Vancouver, ISO, and other styles
18

Wellock, I. J., G. C. Emmans, and I. Kyriazakis. "Describing and predicting potential growth in the pig." Animal Science 78, no. 3 (June 2004): 379–88. http://dx.doi.org/10.1017/s1357729800058781.

Full text
Abstract:
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.
APA, Harvard, Vancouver, ISO, and other styles
19

Ismail, Zuhaimy, Azme Khamis, and Md Yunus Jaafar. "Fitting Nonlinear Gompertz Curve to Tobacco Growth Data." Journal of Agronomy 2, no. 4 (September 15, 2003): 223–36. http://dx.doi.org/10.3923/ja.2003.223.236.

Full text
APA, Harvard, Vancouver, ISO, and other styles
20

Albano, G., V. Giorno, P. Román-Román, S. Román-Román, J. J. Serrano-Pérez, and F. Torres-Ruiz. "Inference on an heteroscedastic Gompertz tumor growth model." Mathematical Biosciences 328 (October 2020): 108428. http://dx.doi.org/10.1016/j.mbs.2020.108428.

Full text
APA, Harvard, Vancouver, ISO, and other styles
21

Laila, Umi, Rifa Nurhayati, Tyas Utami, and Endang Sutriswati Rahayu. "Prediction of Microbial Population in Sorghum Fermentation through Mathematical Models." Reaktor 19, no. 4 (December 31, 2019): 152–61. http://dx.doi.org/10.14710/reaktor.19.4.152-161.

Full text
Abstract:
The mathematical models can be used as a tool in predicting microbial population in sorghum fermentation, either spontaneous fermentation or fermentation with the addition of lactic acid bacteria (LAB) inoculum. Gompertz model modified by Gibson, Gompertz model modified by Zwietering, Baranyi-Robert model, Fujikawa model, Richards model, Schnute model were used in predicting the growth of lactic acid bacteria (LAB) and coliform bacteria during spontaneous fermentation, and also the growth of LAB during fermentation with the addition of inoculum. Meanwhile, there was death (inactivation) of coliform bacteria during sorghum fermentation with the addition of LAB inoculum. The Geeraerd model and the Gompertz model modified by Gil et al. were used to predict the inactivation. The accuracy and precision of models were evaluated based on the Root Mean of Sum Square Error (RMSE), coefficient of determination (R2), and curve fitting. Gompertz model modified by Gibson had the highest accuracy and precision, which was followed by the accuracy of the Fujikawa model and Baranyi-Robert model in predicting the growth of LAB and the growth of coliform bacteria during spontaneous fermentation. Meanwhile, in predicting LAB growth during fermentation with the addition of inoculum, high accuracy and precision was obtained from Richards and Schnute models. In predicting the inactivation of coliform bacteria, Geeraerd model provided higher accuracy and precision compared to Gompertz model modified by Gil et al. Keywords: fermentation; inoculum; mathematical; model; sorghum; spontaneous
APA, Harvard, Vancouver, ISO, and other styles
22

Bajzer, Željko, and Stanimir Vuk-Pavlovic. "New Dimensions in Gompertzian Growth." Journal of Theoretical Medicine 2, no. 4 (2000): 307–15. http://dx.doi.org/10.1080/10273660008833057.

Full text
Abstract:
The Gompertz function was formulated to represent an actuarial curve, yet it often fits growth of organisms, organs and tumors. Despite numerous attempts, no consensus has been forged about the biological foundation of the broad applicability of the model. Here we revisit the Gompertzian notion of the “power to grow” and equate it with growth fraction. Aside from conferring biological interpretability to the model, this approach allows leading to the possibility of exploring the behavior of Gompertzian growth with fractal kinetics. Significantly, we found that empirical models such as the logistic model, the von Bertalanffy model and the von Bertalanffy Richards model, together with the originative Gompertz model, are special cases of Gampertzian growth in fractal space. This finding permits an analysis of the growth kinetics of tumors which might affect model based design of Chemotherapy protocols.
APA, Harvard, Vancouver, ISO, and other styles
23

Bem, Cláudia Marques de, Alberto Cargnelutti Filho, Giovani Facco, Denison Esequiel Schabarum, Daniela Lixinski Silveira, Fernanda Martins Simões, and Daniela Barbieri Uliana. "Growth models for morphological traits of sunn hemp." Semina: Ciências Agrárias 38, no. 5 (October 3, 2017): 2933. http://dx.doi.org/10.5433/1679-0359.2017v38n5p2933.

Full text
Abstract:
The objective of the present study was to fit Gompertz and Logistic nonlinear to descriptions of morphological traits of sunn hemp. Two uniformity trials were conducted and the crops received identical treatment in all experimental area. Sunn hemp seeds were sown in rows 0.5 m apart with a plant density of 20 plants per row meter in a usable area of 52 m × 50 m. The following morphological traits were evaluated: plant height (PH), number of leaves (NL), stem diameter (SD), and root length (RL). These traits were assessed daily during two sowing periods—seeds were sown on October 22, 2014 (first period) and December 3, 2014 (second period). Four plants were randomly collected daily, beginning 7 days after first period and 13 days after for second period, totaling 94 and 76 evaluation days, respectively. For Gompertz models the equation was used y=a*e^((?-e?^((b-c*xi))and Logistic models the equation was used yi= a/(1+e^((-b-c*xi)). The inflection points of the Gompertz and Logistic models were calculated and the goodness of fit was quantified using the adjusted coefficient of determination, Akaike information criterion, standard deviation of residuals, mean absolute deviation, mean absolute percentage error, and mean prediction error. Differences were observed between the Gompertz and Logistic models and between the experimental periods in the parameter estimate for all morphological traits measured. Satisfactory growth curve fittings were achieved for plant height, number of leaves, and stem diameter in both models using the evaluation criteria: coefficient of determination (R²), Akaike information criterion (AIC), standard deviation of residuals (SDR), mean absolute deviation (MAD), mean absolute percentage error (MAPE), and mean prediction error (MPE).
APA, Harvard, Vancouver, ISO, and other styles
24

Markov, Svetoslav Marinov. "The Gompertz model revisited and modified using reaction networks: Mathematical analysis." BIOMATH 10, no. 2 (October 4, 2021): 2110023. http://dx.doi.org/10.11145/j.biomath.2021.10.023.

Full text
Abstract:
In the present work we discuss the?usage of the framework of chemical reaction networks for the construction of dynamical models and their mathematical analysis. To this end, the process of construction of reaction-network-based models via mass action kinetics is introduced and illustrated on several familiar examples,?such as the exponential (radioactive) decay, the logistic and the Gompertz models. Our final goal is to modify the reaction network of the classic Gompertz model in a natural way using certain features of the exponential decay and the logistic models. The growth function of the obtained new Gompertz-type hybrid model possesses an additional degree of freedom (one more rate parameter) and is thus more flexible when applied to numerical simulation of measurement and experimental data sets. More specifically, the ordinate (height) of the inflection point of the new generalized Gompertz model can vary in the interval (0, 1/e], whereas the respective height of the classic Gompertz model is fixed at 1/e (assuming the height of the upper asymptote is one). It is shown that?the new model is a generalization of both the classic Gompertz model and the one-step exponential decay model.?Historically the Gompertz function has been first used for statistical/insurance purposes, much later this function has been applied to simulate biological growth data sets coming from various fields of science, the reaction network approach explains and unifies the two approaches.
APA, Harvard, Vancouver, ISO, and other styles
25

LU, ZHENG, JOSEPH G. SEBRANEK, JAMES S. DICKSON, AUBREY F. MENDONCA, and THEODORE B. BAILEY. "Application of Predictive Models To Estimate Listeria monocytogenes Growth on Frankfurters Treated with Organic Acid Salts." Journal of Food Protection 68, no. 11 (November 1, 2005): 2326–32. http://dx.doi.org/10.4315/0362-028x-68.11.2326.

Full text
Abstract:
Organic acid salts including sodium lactate, sodium diacetate, potassium benzoate, potassium sorbate, and their combinations were assessed as potential inhibitors of Listeria monocytogenes growth on frankfurters. Predictive models for L. monocytogenes growth on frankfurters treated with these salts were compared to select a proper L. monocytogenes growth curve model under these conditions. Sigmoidal equations, including logistic and Gompertz equations, are widely used to describe bacterial growth. In this study, the reparameterized Gompertz model provided a better fit to the L. monocytogenes growth data compared with the other models that were included in this study. Rather than a fixed value for the maximum number of organisms, the reparameterized Gompertz model allows this quantity to be estimated from the data to determine the effect, if any, of the treatments on maximum population density. This information is expected to improve practical methodology for hazard characterization of microbial pathogens on ready-to-eat meat products.
APA, Harvard, Vancouver, ISO, and other styles
26

Paek, Jayeong, and Ilsu Choi. "Bayesian Inference of the Stochastic Gompertz Growth Model for Tumor Growth." Communications for Statistical Applications and Methods 21, no. 6 (November 30, 2014): 521–28. http://dx.doi.org/10.5351/csam.2014.21.6.521.

Full text
APA, Harvard, Vancouver, ISO, and other styles
27

Adamu, J., A. Y. Shuaibu, and A. O. Raji. "Growth characteristics of noiler chickens as determined by nonlinear algorithms." Nigerian Journal of Animal Production 48, no. 5 (November 10, 2021): 12–19. http://dx.doi.org/10.51791/njap.v48i5.3183.

Full text
Abstract:
The assessment of growth characteristics of noilers chickens as determined by non- linear algorithms will provide the best mathematical function in the growth of male and female noilers chickens This study sought to determine the adequacy of two mathematical functions for modeling growth characteristics of male and female Noiler® chickens. Body weights and morphometric traits of 200 Noiler chickens were measured bimonthly for 20 weeks and the data obtained fitted to the Gompertz and Logistic growth models using the nonlinear regression. The results showed significant (P<0.05) difference between males and females only at 16, 18 and 20 weeks of age, with values of 2316.2 vs 2121.9 g, 2624.3 vs 2378.1 g, and 3002.7 vs 2718.7g, respectively. There were no discernable differences between males and females for most body measurements except body length which was longer in the latter than former from 14 weeks of age. The asymptomatic weight (A) of the models revealed that Gompertz model had higher values for both male and female Noilers than the Logistic for body weight and all morphometric traits. The reverse was observed with the scale parameter 2 (B) and relative growth rate (C) for all traits. The coefficient of determination (R ) values for both models (male and female) were generally high (>80%) indicating a good fit for the data. The other goodness of fit criteria; Akaike Information Criterion (AIC) and standard deviation (SD) were lower for the Gompertz compared to Logistic for both male and female. Thus, the study revealed that the Gompertz was the better model for explaining the growth patterns of both male and female Noiler chickens. L'évaluation des caractéristiques de croissance des poulets de Noilers tels que déterminées par des algorithmes non linéaires fournira la meilleure fonction mathématique de la croissance des poulets de Noilers masculins et féminins. Cette étude a cherché à déterminer l'adéquation de deux fonctions mathématiques pour la modélisation des caractéristiques de croissance des poulets mâles et femelles Noiler. Les poids corporels et les traits morphométriques de 200 poulets nilaques ont été mesurés bimenshly pendant 20 semaines et les données obtenues dans les modèles de Gompertz et croissance logistiques utilisant la régression non linéaire. Les résultats ont montré une différence significative (p <0,05) entre les mâles et les femmes seulement à 16, 18 et 20 semaines, avec des valeurs de 2316,2 vs 2121,9 g, 2624.3 contre 2378,1 g et 3002,7 vs 2718.7g, respectivement. Il n'y avait pas de différences discernables entre les hommes et les femmes pour la plupart des mesures du corps, à l'exception de la longueur du corps, ce qui était plus long que l'ancien de 14 semaines. Le poids asymptomatique (A) des modèles a révélé que le modèle de Gompertz avait des valeurs plus élevées pour les noilers mâles et femelles que la logistique pour le poids corporel et tous les traits morphométriques. L'inverse a été observé avec le paramètre d'échelle (B) et le taux de croissance relative (C) pour tous les traits. Le coefficient de valeurs de détermination (R ) pour les deux modèles (hommes et femmes) était généralement élevé (> 80%) indiquant un bon ajustement pour les données. L'autre bonté des critères d'ajustement; Le critère d'information Akaike (CIA) et l'écart type (ET) étaient plus bas pour le Gompertz par rapport à la logistique pour les hommes et les femmes. Ainsi, l'étude a révélé que le Gompertz était le meilleur modèle d'explication des schémas de croissance des poulets mâles et femelles Noilers.
APA, Harvard, Vancouver, ISO, and other styles
28

Shukor, Mohd Yunus. "Test for the presence of autocorrelation in the modified Gompertz model used in fitting of Burkholderia sp. strain Neni-11 growth on acrylamide." Bioremediation Science and Technology Research 4, no. 2 (December 31, 2016): 25–27. http://dx.doi.org/10.54987/bstr.v4i2.372.

Full text
Abstract:
The growth of microorganism on substrates, whether toxic or not usually exhibits sigmoidal pattern. This sigmoidal growth pattern can be modelled using primary models such as Logistic, modified Gompertz, Richards, Schnute, Baranyi-Roberts, Von Bertalanffy, Buchanan three-phase and Huang. Previously, the modified Gompertz model was chosen to model the growth of Burkholderia sp. strain Neni-11 on acrylamide, which shows a sigmoidal curve. The modified Gompertz model relies on the ordinary least squares method, which in turn relies heavily on several important assumptions, which include that the data does not show autocorrelation. In this work we perform statistical diagnosis test to test for the presence of autocorrelation using the Durbin-Watson test and found that the model was adequate and robust as no autocorrelation of the data was found.
APA, Harvard, Vancouver, ISO, and other styles
29

Ruiz-Arrebola, Samuel, Damián Guirado, Mercedes Villalobos, and Antonio M. Lallena. "Evaluation of Classical Mathematical Models of Tumor Growth Using an On-Lattice Agent-Based Monte Carlo Model." Applied Sciences 11, no. 11 (June 4, 2021): 5241. http://dx.doi.org/10.3390/app11115241.

Full text
Abstract:
Purpose: To analyze the capabilities of different classical mathematical models to describe the growth of multicellular spheroids simulated with an on-lattice agent-based Monte Carlo model that has already been validated. Methods: The exponential, Gompertz, logistic, potential, and Bertalanffy models have been fitted in different situations to volume data generated with a Monte Carlo agent-based model that simulates the spheroid growth. Two samples of pseudo-data, obtained by assuming different variability in the simulation parameters, were considered. The mathematical models were fitted to the whole growth curves and also to parts of them, thus permitting to analyze the predictive power (both prospective and retrospective) of the models. Results: The consideration of the data obtained with a larger variability of the simulation parameters increases the width of the χ2 distributions obtained in the fits. The Gompertz model provided the best fits to the whole growth curves, yielding an average value of the χ2 per degree of freedom of 3.2, an order of magnitude smaller than those found for the other models. Gompertz and Bertalanffy models gave a similar retrospective prediction capability. In what refers to prospective prediction power, the Gompertz model showed by far the best performance. Conclusions: The classical mathematical models that have been analyzed show poor prediction capabilities to reproduce the MTS growth data not used to fit them. Within these poor results, the Gompertz model proves to be the one that better describes the growth data simulated. The simulation of the growth of tumors or multicellular spheroids permits to have follow-up periods longer than in the usual experimental studies and with a much larger number of samples: this has permitted performing the type of analysis presented here.
APA, Harvard, Vancouver, ISO, and other styles
30

Halmi, M. I. E., M. S. Shukor, W. L. W. Johari, and Mohd Yunus Abd Shukor. "Modeling the growth curves of Acinetobacter sp. strain DRY12 grown on diesel." Journal of Environmental Bioremediation and Toxicology 2, no. 1 (July 31, 2014): 33–37. http://dx.doi.org/10.54987/jebat.v2i1.143.

Full text
Abstract:
Diesel is a toxic xenobiotic. However, some bacteria are capable of using diesel as a carbon source for energy and growth. At high diesel concentration, an inhibition to the growth curves is seen. The study of the growth inhibitory properties of diesel on bacterium has often been carried out through the modelling of the specific growth rates obtained from the linearization of thegrowth curves of bacterium. Since there exists a variety of models for obtaining a more accurate specific growth rates from bacterial growth curves such as logistic, Gompertz, Richards, Schnute, Baranyi-Roberts, Von Bertalanffy, Buchanan three-phase and more recently Huang models, theuse of these models over the simplification through linearization is needed. The modified Gompertz model gave the best fitting based on statistical test with the lowest values for RMSE and corrected Akaike Information Criteria, the highest value for adjusted R2 and the closest values to unity for both Accuracy and Bias factors. The modified Gompertz model is thus the best model to obtain specific growth rates from the growth curves of Acinetobacter sp. strain DRY12grown on diesel.
APA, Harvard, Vancouver, ISO, and other styles
31

Lee, Sang-Un. "Estimation of Software Project Success and Completion Rate Using Gompertz Growth Function." KIPS Transactions:PartD 13D, no. 5 (October 1, 2006): 709–16. http://dx.doi.org/10.3745/kipstd.2006.13d.5.709.

Full text
APA, Harvard, Vancouver, ISO, and other styles
32

PALUMBO, SAMUEL A., AARON C. WILLIAMS, ROBERT L. BUCHANAN, and JOHN G. PHILLIPS. "Model for the Aerobic Growth of Aeromonas hydrophila K144." Journal of Food Protection 54, no. 6 (June 1, 1991): 429–35. http://dx.doi.org/10.4315/0362-028x-54.6.429.

Full text
Abstract:
The combined effects of temperature (5 to 42°C), NaCl (0.5 to 4.5%), pH (5.3 to 7.3), and NaN02 (0 to 200 μg/ml) on the aerobic growth of Aeromonas hydrophila K144 were studied in brain heart infusion (BHI) broth using a modified central composite design. Variable combinations were tested in triplicate aerobic flasks; viable cell counts were made at intervals during incubation by surface plating on tryptic soy agar. Growth curves were generated using the Gompertz equation in conjunction with a nonlinear iterative regression analysis. Values for the four Gompertz parameters (A, C, B, and M) were obtained for the variable combinations tested. Using response surface techniques, quadratic and cubic equations containing the four variables of temperature, pH, NaCl, and NaN02 were developed to yield predictive values for the B and M Gompertz values. Goodness of fit evaluation of the models was by R2 values. Comparison of predicted and observed values of B and M and evaluation of predicted lag times and generation times indicated that the quadratic model gave a better fit. Overall, the variable combinations interacted to decrease the generation time and increase the lag time. The results indicate that pH, salt, and nitrite can decrease the growth of A. hydrophila when combined with low temperature incubation.
APA, Harvard, Vancouver, ISO, and other styles
33

WHITTEMORE, C. T., and D. M. GREEN. "The description of the rate of protein and lipid growth in pigs in relation to live weight." Journal of Agricultural Science 138, no. 4 (June 2002): 415–23. http://dx.doi.org/10.1017/s0021859602002186.

Full text
Abstract:
The paper seeks to compare the effectiveness of various functions as appropriate to express protein retention and lipid retention as a function of pig live weight. Linear descriptors were adequate for protein growth over the 20 to 120 kg live weight range, but not adequate when higher live weights were included. Linear descriptors were not adequate for lipid growth over any weight range. Quadratic and cubic polynomials, and the logistic function, were faulted on their failure to describe the known biology. Augmentation of the allometric function added nothing to the simple form. The Gompertz function was consistently effective for the description of daily protein retention rate. The Bridges and Richards functions are more flexible than the Gompertz with respect to the point of inflection, but when applied they resembled the Gompertz and therefore did not materially influence the descriptive outcome. The cubic polynomial, augmented allometric, Bridges and Richards functions, although favoured in other reports, were found to add nothing to the more simple functions. It is concluded that protein retention can be well expressed in relation to live weight by linear and Gompertz functions. Lipid retention could be well described by an allometric relationship with pig mass.
APA, Harvard, Vancouver, ISO, and other styles
34

Widiharih, Tatik, and Budi Warsito. "Rancangan D-Optimal Model Gompertz dengan Maple." MEDIA STATISTIKA 10, no. 1 (August 14, 2017): 1. http://dx.doi.org/10.14710/medstat.10.1.1-12.

Full text
Abstract:
Gompertz model is used in many areas including biological growth studies, animal and husbandry, chemistry, and agricultural. Locally D-optimal designs for Gompertz models with three parameters is investigated. We used the Generalized Equivalence Theorem of Kiefer and Wolvowitz to determine D-optimality criteria. Tchebysheff system is used to decide that the D-optimal design is minimally supported design or nonminimally supported design. The result, D-optimal design for Gompertz model is minimally supported design with uniform weight on its support.Keywords:D-optimal, Generalized Equivalence Theorem, Tchebysheff System, Minimally Supported, Uniform Weight.
APA, Harvard, Vancouver, ISO, and other styles
35

Wang, Jianming, Junran Chen, Yunfeng Hu, Hanyan Hu, Guohua Liu, and Ruixiang Yan. "Application of a Predictive Growth Model of Pseudomonas spp. for Estimating Shelf Life of Fresh Agaricus bisporus." Journal of Food Protection 80, no. 10 (September 7, 2017): 1676–81. http://dx.doi.org/10.4315/0362-028x.jfp-17-055.

Full text
Abstract:
ABSTRACT For prediction of the shelf life of the mushroom Agaricus bisporus, the growth curve of the main spoilage microorganisms was studied under isothermal conditions at 2 to 22°C with a modified Gompertz model. The effect of temperature on the growth parameters for the main spoilage microorganisms was quantified and modeled using the square root model. Pseudomonas spp. were the main microorganisms causing A. bisporus decay, and the modified Gompertz model was useful for modelling the growth curve of Pseudomonas spp. All the bias factors values of the model were close to 1. By combining the modified Gompertz model with the square root model, a prediction model to estimate the shelf life of A. bisporus as a function of storage temperature was developed. The model was validated for A. bisporus stored at 6, 12, and 18°C, and adequate agreement was found between the experimental and predicted data.
APA, Harvard, Vancouver, ISO, and other styles
36

Markov, Svetoslav Marinov. "Reaction networks reveal new links between Gompertz and Verhulst growth functions." BIOMATH 8, no. 1 (April 21, 2019): 1904167. http://dx.doi.org/10.11145/j.biomath.2019.04.167.

Full text
Abstract:
New reaction network realizations of the Gompertz and logistic growth models are proposed. The proposed reaction networks involve an additional species interpreted as environmental resource. Some natural generalizations and modifications of the Gompertz and the logistic models, induced by the proposed networks, are formulated and discussed. In particular, it is shown that the induced dynamical systems can be reduced to one dimensional differential equations for the growth (resp. decay) species. The reaction network formulation of the proposed models suggest hints for the intrinsic mechanism of the modeled growth process and can be used for analyzing evolutionary measured data when testing various appropriate models, especially when studying growth processes in life sciences.
APA, Harvard, Vancouver, ISO, and other styles
37

Duan-Yai, S., B. A. Young, A. Lisle, J. A. Coutts, and J. B. Gaughan. "Growth Data of Broiler Chickens Fitted to Gompertz Function." Asian-Australasian Journal of Animal Sciences 12, no. 8 (December 1, 1999): 1177–80. http://dx.doi.org/10.5713/ajas.1999.1177.

Full text
APA, Harvard, Vancouver, ISO, and other styles
38

Lo, C. F. "A Modified Stochastic Gompertz Model for Tumour Cell Growth." Computational and Mathematical Methods in Medicine 11, no. 1 (2010): 3–11. http://dx.doi.org/10.1080/17486700802545543.

Full text
Abstract:
Based upon the deterministic Gompertz law of cell growth, we have proposed a stochastic model of tumour cell growth, in which the size of the tumour cells is bounded. The model takes account of both cell fission (which is an ‘action at a distance’ effect) and mortality too. Accordingly, the density function of the size of the tumour cells obeys a functional Fokker–Planck Equation (FPE) associated with the bounded stochastic process. We apply the Lie-algebraic method to derive the exact analytical solution via an iterative approach. It is found that the density function exhibits an interesting kink-like structure generated by cell fission as time evolves.
APA, Harvard, Vancouver, ISO, and other styles
39

Jenner, Adrianne L., Peter S. Kim, and Federico Frascoli. "Oncolytic virotherapy for tumours following a Gompertz growth law." Journal of Theoretical Biology 480 (November 2019): 129–40. http://dx.doi.org/10.1016/j.jtbi.2019.08.002.

Full text
APA, Harvard, Vancouver, ISO, and other styles
40

Easton, Dexter M. "X-Ray Survival as Gompertz Growth in Number Killed." Journal of Theoretical Biology 196, no. 1 (January 1999): 1–8. http://dx.doi.org/10.1006/jtbi.1998.0812.

Full text
APA, Harvard, Vancouver, ISO, and other styles
41

Zhang, Lu, Emilio Laca, Cara J. Allan, Narges M. Mahvelati, and Louise Ferguson. "Nonlinear Model Selection for Fruit and Kernel Development as a Function of Heat in Pistachio." HortScience 56, no. 7 (July 2021): 769–79. http://dx.doi.org/10.21273/hortsci15722-21.

Full text
Abstract:
Knowing a tree crop’s seasonal growth and development as a function of heat accumulation can facilitate scheduling of irrigation, pesticide applications, and harvest. Our objective was to compare the goodness of fit of applied models and determine which provides the best description of pistachio nut growth as a function of thermal unit accumulation. Three fruit growth traits of pistachio—pericarp (hull) + endocarp (shell) size, endocarp thickening and hardening, and embryo (kernel) size—exhibited clear nonlinear dependence on heat accumulation. We tested three nonlinear models—Michaelis–Menten, three-parameter logistic, and Gompertz—fitted to fruit development data to create a tool to forecast pest susceptibility and harvest timing. Observation of development began at full bloom and ended at harvest. Data were collected from six pistachio cultivars in one experimental and eight commercial orchards over 3 years. Analyses of residual distribution, parameter standard errors, coefficient of determination (R2) and the Akaike information criterion (AIC) all demonstrated the Gompertz function was the best model. Cultivars differed significantly in all the three parameters (Asym, b, and c) for all three traits with the Gompertz model, demonstrating the Gompertz model can adjust to incorporate cultivar differences. The growth curve of the three traits together provided integrated information on nut biomass accumulation that facilitates predicting the critical timing for multiple orchard management practices.
APA, Harvard, Vancouver, ISO, and other styles
42

Rice, Roy E. "Using the Gompertz Reliability Growth Model to Model Prognostics Growth and Maturity." Military Operations Research 16, no. 1 (March 15, 2011): 57–64. http://dx.doi.org/10.5711/1082598316157.

Full text
APA, Harvard, Vancouver, ISO, and other styles
43

Rotgé, Hector G. Riveros, and David Riveros Rosas. "COVID19 Pandemic evolution through Gompertz’s equation." South Florida Journal of Development 2, no. 3 (August 5, 2021): 4807–16. http://dx.doi.org/10.46932/sfjdv2n3-074.

Full text
Abstract:
ABSTRACT The Gompertz equation describes the evolution of an epidemic. Applied to the data from France, Spain, Germany, and the United Kingdom, it is adjusted with slight deviations since each country implemented different restriction or distancing measures to prevent the spread. Some countries do not conform to Gompertz. With the data from Mexico, the graphs show that the measured and calculated data are overlapped. The deviations are not noticeable. We made adjustments with data up to recent dates. For the four countries, Gompertz predicts well the evolution of the epidemic. We tried to predict the growth of the epidemic using Gompertz. For Mexico, the maximum number of daily infections was predicted up to a month before it happened. RESUMEN La ecuación de Gompertz describe la evolución de una epidemia. Aplicada a los datos de Francia, España, Alemania y el Reino Unido, se ajusta con ligeras desviaciones, ya que cada país aplicó diferentes medidas de restricción o distanciamiento para evitar la propagación. Algunos países no se ajustan a Gompertz. Con los datos de México, los gráficos muestran que los datos medidos y los calculados se superponen. Las desviaciones no son perceptibles. Hemos realizado ajustes con datos hasta fechas recientes. Para los cuatro países, Gompertz predice bien la evolución de la epidemia. Intentamos predecir el crecimiento de la epidemia con Gompertz. Para México, se predijo el número máximo de contagios diarios hasta un mes antes de que se produjera.
APA, Harvard, Vancouver, ISO, and other styles
44

Fajar, Muhammad, and Wahyudi Wahyudi. "Modeling of COVID-19 Epidemic Growth Curve in Indonesia." Jurnal Matematika MANTIK 7, no. 1 (May 31, 2021): 67–73. http://dx.doi.org/10.15642/mantik.2021.7.1.67-73.

Full text
Abstract:
Aim of this study is to make parametric modeling of the COVID-19 epidemic growth curve so that the maximum value and time at that point can be obtained from the cumulative cases of COVID-19. The data used in this study is the cumulative number of positive confirmed cases of COVID-19 from https://covid19.go.id/. The method used in this study is fitting data with the Logistic and Gompertz models. Result of this study are (1) the Logistic and Gompertz models are very fit in modeling the COVID-19 epidemic growth curve, indicated from the value of R2 (coefficient of determination) which reaches more than 99%; (2) From the Logistics model it is obtained that the estimated amount of the maximum cumulative case at the end of the COVID-19 epidemic is 7,714 positive confirmed cases, achieved in about 82 days (May 22, 2020) from Mar 2, 2020, when the first positive COVID-19 case was announced by the government; and (3) From the Gompertz model, it is obtained that the estimated maximum cumulative case at the end of the COVID-19 epidemic is 33,975 positive confirmed cases, achieved in about 152 days (Jul 30, 2020) from Mar 2, 2020. The results of this study can be used as input to the government to take steps in controlling the spread of COVID-19.
APA, Harvard, Vancouver, ISO, and other styles
45

Fang, Shih-Lun, Yu-Hsien Kuo, Le Kang, Chu-Chung Chen, Chih-Yu Hsieh, Min-Hwi Yao, and Bo-Jein Kuo. "Using Sigmoid Growth Models to Simulate Greenhouse Tomato Growth and Development." Horticulturae 8, no. 11 (November 2, 2022): 1021. http://dx.doi.org/10.3390/horticulturae8111021.

Full text
Abstract:
Mathematical modeling has been used to describe the characteristics of crop growth. Establishing a growth model can help to better understand the responses of crops to their environment and improve the efficiency of agricultural production. This study establishes empirical growth models to predict the growth of greenhouse tomato. In this study, we collected beef tomato (Solanum lycopersicum cv. ‘993′) growth data over two crop seasons in Taiwan and established growth models by employing the commonly used Gompertz and Logistic curves. Days after transplanting (DAT) and growing degree-days (GDD) were introduced as independent variables and their relationships with five traits, i.e., plant height, leaf area index, stem dry matter, leaves dry matter, and fruits dry matter were determined. The performances of GDD models were slightly better than those of the DAT models. In addition, we inferred five critical points with biological meaning based on the proposed growth models. The critical points estimated by the Logistic model are closer to our expectation than those of the Gompertz model, and they were applicable for the ‘993′ tomato in Taiwan. These results can be used to predict tomato growth and adjust the fieldwork schedule to improve the efficiency of the greenhouse production of tomatoes.
APA, Harvard, Vancouver, ISO, and other styles
46

Atmaja, Suherman Banon. "KETIDAKSTABILAN BESARAN STOK IKAN DARI MODEL PRODUKSI SURPLUS." Jurnal Penelitian Perikanan Indonesia 13, no. 1 (February 9, 2017): 1. http://dx.doi.org/10.15578/jppi.13.1.2007.1-11.

Full text
Abstract:
Selama ini, kerangka pengelolaan sumber daya ikan berdasarkan pada titik acuan nilai potensi dan kriteria maksimum (maximum sustainable yield), mengabaikan laju pertumbuhan stok ikan dan tanpa memperhatikan dinamika perikanan yang terjadi. Dari kombinasi data yang tersedia diperoleh hasil besaran nilai stok ikan yang bersifat dinamis, akibat perubahan yang terjadi pada parameter–parameter model produksi surplus. Tingkat maximum sustainable yield menunjukkan CMSY darimetode Gompertz lebih tinggi dibandingkan dengan metode logistik, sebaliknya tingkat EMSY lebih rendah dibandingkan dengan metode logistik. Konsekuensi perbedaan tersebut menghasilkan tingkat BMSY dan tercapai puncak titik jenuh dari perikanan pukat cincin berbeda, untuk metode Gompertz (37% dari biomassa awal) terjadi pada kurun waktu tahun 1978 sampai dengan 1981, sedangkan untuk metode logistik (50% dari biomassa awal) terjadi pada kurun waktu tahun 1990 sampai dengan 1992. Kondisi trend biomassa menunjukkan penurunan biomassa berkisar 92 sampai dengan 96,5% dari biomassa awal untuk metode Gompertz, sedangkan untuk metode logistik berkisar 70 sampai dengan 93%. Tampak perkembangan perikanan pukat cincin catch effort mengikuti fungsi pertumbuhan logistik daripada fungsi pertumbuhan Gompertz. Bagaimanapun, penyusutan stok ikan pelagis didukung oleh trend hasil tangkapan yang menurun, sedangkan hari operasi cenderung meningkat. During the time, framework of fisheries resources management was based on reference point of potency value and criteria (maximum sustainable yield), while net growth of fish stock and fisheries dynamics have been ignored. From data combination available obtaining result of size of fish stocks was dynamic due to change of parameters of surplus production. The Level maximum sustainable yield showes that CMSY method of Gompertz was higher than logistics method, on the contrary EMSY compared to lower than logistics method. Consequently, these results were obtained the level of BMSY (biomass at level maximum sustainable yield) and the peaks of exploitation from purse seine fishery were also diffrent, for Gompertz method revealed that the level of BMSY (37% from initially biomass) occurred in the period of 1978 to 1981, while logistics method (50% from initially biomass) occurred in the period of 1990 to 1992. Trend biomass in state of decline reached 92 to 96,5% from intially biomass for Gompertz method, while for the method of logistics reached 70 to 93% from intially biomass. Seems that the development of purse seine fisheries (catch effort) followed function growth logistics rather than the function growth Gompertz. However, the decrease of fish stock pelagic supported by the catch of pelagic fish showed a declining trend, while fishing days have tend to increase.
APA, Harvard, Vancouver, ISO, and other styles
47

Vilanova, Alba, Bo-Young Kim, Chang Ki Kim, and Hyun-Goo Kim. "Linear-Gompertz Model-Based Regression of Photovoltaic Power Generation by Satellite Imagery-Based Solar Irradiance." Energies 13, no. 4 (February 11, 2020): 781. http://dx.doi.org/10.3390/en13040781.

Full text
Abstract:
A simple yet accurate photovoltaic (PV) performance curve as a function of satellite-based solar irradiation is necessary to develop a PV power forecasting model that can cover all of South Korea, where more than 35,000 PV power plants are currently in operation. In order to express the nonlinear power output of the PV module with respect to the hourly global horizontal irradiance derived from satellite images, this study employed the Gompertz model, which is composed of three parameters and the sigmoid equation. The nonphysical behavior of the Gompertz model within the low solar irradiation range was corrected by combining a linear equation with the same gradient at the conjoint point. The overall fitness of Linear-Gompertz regression to the 242 PV power plants representing the country was R2 = 0.85 and nRMSE = 0.09. The Gompertz model coefficients showed normal distributions and equivariance of standard deviations of less than 15% by year and by season. Therefore, it can be conjectured that the Linear-Gompertz model represents the whole country’s PV system performance curve. In addition, the Gompertz coefficient C, which controls the growth rate of the curve, showed a strong correlation with the capacity factor, such that the regression equation for the capacity factor could be derived as a function of the three Gompertz model coefficients with a fitness of R2 = 0.88.
APA, Harvard, Vancouver, ISO, and other styles
48

VADASZ, PETER, and ALISA S. VADASZ. "ON THE GOMPERTZ LIMIT OF THE MONOTONIC NEOCLASSICAL GROWTH MODEL." Journal of Mechanics in Medicine and Biology 09, no. 01 (March 2009): 63–80. http://dx.doi.org/10.1142/s0219519409002857.

Full text
Abstract:
The burden of proof of any theory aiming to represent a physical or biological reality by demonstrating its unifying properties is applied in the present paper in relation to the Neoclassical growth model and its ability to reproduce Gompertz growth. The Neoclassical growth model derived from first biological and physical principles was shown to capture all qualitative features that were revealed experimentally, including the possibility of a Logarithmic Inflection Point (LIP), the possibility of a LAG, concave as well as convex curves on the phase diagram, the Logistic growth as a special case, growth followed by decay, as well as oscillations. In addition, quantitative validation demonstrated its ability to reproduce experimental data in a few tested cases. This paper demonstrates that the Neoclassical growth model can reproduce a Generalized version of Gompertz growth too.
APA, Harvard, Vancouver, ISO, and other styles
49

Yamada, Kyoichiro. "Prognosis of Aphasia by Fitting Growth Curves." Perceptual and Motor Skills 68, no. 3_suppl (June 1989): 1147–50. http://dx.doi.org/10.2466/pms.1989.68.3c.1147.

Full text
Abstract:
The recovery of word-emission ability by Japanese aphasics was examined quantitatively. The scores on a word-emission task were obtained in a series of language tests for aphasia. 17 aphasics were asked to utter names of animals, giving as many as possible within a minute. The task was repeated four times at intervals of 104.1 days on the average, ranging from 27 to 271 days. The score on the word-emission task was estimated by fitting a growth curve to scores on the former three tests. Modified exponential, logistic, and Gompertz curves were used for estimation. All estimated scores by three growth curves were larger than the observed scores. The modified exponential curve which does not have an inflection point produced the most remarkable error. Between two curves which have an inflection point the logistic curve produced less error than the Gompertz curve. The difference in error of estimation was due to the difference in the saturation level of the two curves.
APA, Harvard, Vancouver, ISO, and other styles
50

Susanti, Triana, and Maijon Purba. "The growth of local white muscovy growth during starter and grower period." Jurnal Ilmu Ternak dan Veteriner 22, no. 2 (March 1, 2018): 63. http://dx.doi.org/10.14334/jitv.v22i2.1615.

Full text
Abstract:
<p>Livestock animals with relatively fast growth and great body weight are potential as a producer of meat. In Indonesia, the local muscovy, especially the feathered white is one of the meat-producing livestock. However, an analysis of the growth on local white muscovy is still rarely done. Therefore, the purpose of this study was to determine the point of inflection as growth variables, thus simplifying the preparation of development programs of local white muscovy. A total of 168 of the local unsex white muscovy were examined for their growth since the DOD until 112 days of age. The data of growth i.e. body weight individually examined in every two weeks. The data were analyzed using Gompertz model. The result obtained was the growth equation of local white Muscovy based on the model of Gompertz: Y=2591.3*exp (-3.8636*exp-0.0272*t). Based on these equations, the point of inflection of the local white muscovy occurred at the age of 50 days with a weight of 953.29 g. The maximum body weight gain achieved was 2591.30 g. It is conclude that the growth of local white muscovy was relatively slow, but the body weight was very heavy.</p>
APA, Harvard, Vancouver, ISO, and other styles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography