Critical points in logistic growth curves and treatment comparisons

Passos, José Raimundo de Souza; Pinho, Sheila Zambello de; Carvalho, Lídia Raquel de; Mischan, Martha Maria

doi:10.1590/s0103-90162012000500004

Cited by 17 publications

(10 citation statements)

References 6 publications

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“…This point can be interpreted as an indication of maximum growth and therefore a plateau. 14 Finally, we calculated the number of days from the start of the epidemic to each peak and plateau point. The empirical means and confidence intervals (eCI) for each duration were estimated by Monte Carlo simulation.…”

Section: Methodsmentioning

confidence: 99%

COVID-19 in South Korea: epidemiological and spatiotemporal patterns of the spread and the role of aggressive diagnostic tests in the early phase

Lee

Hwang

Song

et al. 2020

International Journal of Epidemiology

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Background South Korea experienced the novel coronavirus disease (COVID-19) outbreak in the early period; thus data from this country could provide significant implications for global mitigation strategies. This study reports how COVID-19 has spread in South Korea and examines the effects of rapid widespread diagnostic testing on the spread of the disease in the early epidemic phase. Methods We collected daily data on the number of confirmed cases, tests and deaths due to COVID-19 from 20 January to 13 April 2020. We estimated the spread pattern with a logistic growth model, calculated the daily reproduction number (Rt) and examined the fatality pattern of COVID-19. Results From the start date of the epidemic in Korea (18 February 2020), the time to peak and plateau were 15.2 and 25 days, respectively. The initial Rt was 3.9 [95% credible interval (CI) 3.7 to 4.2] and declined to <1 after 2 weeks. The initial epidemic doubling time was 3.8 days (3.4 to 4.2 days). The aggressive testing in the early days of the epidemic was associated with reduction in transmission speed of COVID-19. In addition, as of 13 April, the case fatality rate of COVID-19 in Korea was 2.1%, suggesting a positive effect of the targeted treatment policy for severe patients and medical resources. Conclusions Our findings provide important information for establishing and revising action plans based on testing strategies and severe patient care systems, needed to address the unprecedented pandemic.

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Section: Methodsmentioning

confidence: 99%

COVID-19 in South Korea: epidemiological and spatiotemporal patterns of the spread and the role of aggressive diagnostic tests in the early phase

Lee

Hwang

Song

et al. 2020

International Journal of Epidemiology

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“…Although there are reports in the literature of tilapia with up to 5 kg mass (FAO, 2012), this value is far from the national average, which is 600g to 1 kg (NOGUEIRA, 2007). Growth stages have different biological significance, being their analysis recommended separately (PASSOS et al, 2012), as the case of tilapia mass above the average. In such cases, should take into account the growing point can be considered almost constant, in other words, when the curve is sufficiently close to the asymptote, indicating no significant difference (MISCHAN et al, 2011).…”

Section: Resultsmentioning

confidence: 99%

Mathematical modeling applied to the growth of tilapia in net cages in the sub middle of the São Francisco river

et al. 2014

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This study aimed to apply mathematical models to the growth of Nile tilapia (Oreochromis niloticus) reared in net cages in the lower São Francisco basin and choose the model(s) that best represents the conditions of rearing for the region. Nonlinear models of Brody, Bertalanffy, Logistic, Gompertz, and Richards were tested. The models were adjusted to the series of weight for age according to the methods of Gauss, Newton, Gradiente and Marquardt. It was used the procedure "NLIN" of the System SAS® (2003) to obtain estimates of the parameters from the available data. The best adjustment of the data were performed by the Bertalanffy, Gompertz and Logistic models which are equivalent to explain the growth of the animals up to 270 days of rearing. From the commercial point of view, it is recommended that commercialization of tilapia from at least 600 g, which is estimated in the Bertalanffy, Gompertz and Logistic models for creating over 183, 181 and 184 days, and up to 1 Kg of mass , it is suggested the suspension of the rearing up to 244, 244 and 243 days, respectively. KEYWORDS: economy, equations, Oreochromis niloticus. MODELAGEM MATEMÁTICA APLICADA AO CRESCIMENTO DE TILÁPIAS EM TANQUES-REDE NO SUBMÉDIO DO SÃO FRANCISCO RESUMO: Este estudo teve como objetivo aplicar modelos matemáticos ao crescimento de tilápias-do-nilo (Oreochromis niloticus) criadas em tanques-rede no

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“…According to the analysis results, a linear-plateau regression model was used to fit the relationships between ISP and yield, and between ISP and N partial productivity, and a parabolic model was selected to fit the relationship between ISP and NUE. These analyses were performed in accordance with the NLIN procedure in SPSS 17.0 (SPSS Institute Inc., Chicago, IL, United States), and the corresponding critical inflection point of the model was determined by following the modified piecewise regression method ( Passos et al, 2012 ). To examine the key determinants for ISP, the relationship between ISP and soil physico-chemical parameters was analyzed using the linear regression procedure of SPSS 17.0 software, and the coefficient of determination of linear regression ( R 2 ) was compared to quantitatively reflect the contribution of soil physico-chemical parameters to the change of ISP.…”

Section: Methodsmentioning

confidence: 99%

Concurrent Improvement in Maize Grain Yield and Nitrogen Use Efficiency by Enhancing Inherent Soil Productivity

Wang

et al. 2022

Front. Plant Sci.

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Quantifying the relationships of maize yield and nitrogen use efficiency (NUE) to inherent soil productivity (ISP) could provide a theoretical basis for implementing strategies that concurrently narrow the yield gap, increase NUE, and improve soil quality. A field study under irrigation conditions was conducted at five locations with large differences in ISP (estimated by maize grain yield without using fertilizers) across various ecological regions in Inner Mongolia, China. Our results showed that the changes in maize yield and nitrogen partial factor productivity (PFPN) to ISP followed a linear-plateau model, with a common inflection point. When ISP was below 8.0 t ha–1, maize yield and PFPN were stagnating at a low level, due to a trade-off between the contribution of soil and chemical fertilizers to yield. When ISP exceeded 8.0 t ha–1, the contribution rate of soil to yield stabilized at 80%, resulting in a simultaneous increase in maize yield by 1.2 t ha–1 and PFPN by 4.6 kg kg–1, for increasing ISP at each t ha–1. Our results indicated that while keeping other management strategies unchanged, to increase maize yield and PFPN by 15% or further 30%, it is necessary to increase ISP to 9.3 and 10.4 t ha–1, respectively. In this scenario, N input will be reduced by 33.5 and 47.5%, and apparent N losses will be reduced by 11.7 and 21.5%, respectively. Therefore, enhancing ISP could lead to a simultaneous improvement in yield and NUE as well as strongly support the green development of maize production.

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Critical points in logistic growth curves and treatment comparisons

Cited by 17 publications

References 6 publications

COVID-19 in South Korea: epidemiological and spatiotemporal patterns of the spread and the role of aggressive diagnostic tests in the early phase

COVID-19 in South Korea: epidemiological and spatiotemporal patterns of the spread and the role of aggressive diagnostic tests in the early phase

Mathematical modeling applied to the growth of tilapia in net cages in the sub middle of the São Francisco river

Concurrent Improvement in Maize Grain Yield and Nitrogen Use Efficiency by Enhancing Inherent Soil Productivity

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