A New Growth Rate Measure in Identifying Extended Gompertz Growth Curve and Development of Goodness-of-fit Test

2021 ◽  
pp. 000806832110372
Author(s):  
Farhana Yeasmin ◽  
Ranadeep Daw ◽  
Bratati Chakraborty ◽  
Arindam Gupta ◽  
Sabyasachi Bhattacharya ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Curve ◽  
Goodness Of Fit ◽  
Growth Models ◽  
Broad Class ◽  
Growth Dynamics ◽  
Living Organism ◽  
Fundamental Aspect ◽  
Mathematical Form ◽  
Goodness Of Fit Test

Growth is a fundamental aspect of a living organism. Growth curves play an important role in explaining the complex dynamics of growth trajectories. The development of a large class of growth models provides more choices to explain complex growth dynamics. However, identifying a suitable growth curve from a broad class of growth models becomes a challenging task. Relative Growth Rate (RGR) is the most popular measure in the growth-related study. It serves many purposes in growth curve literature, including constructing any goodness-of-fit index of some growth dynamics. However, the goodness-of-fit test based on RGR is restricted to only simple growth models. This study aims to develop a new growth rate function, instantaneous maturity rate (IMR), which can play an important role in identifying growth models. We have explored that the measure has synergy in mathematical form with IMR. However, unlike the hazard rate, IMR is a random variable when the size/RGR variable is stochastic. We have derived the exact and asymptotic distribution of this measure under the Gaussian setup of both the size and RGR variables. We have constructed a goodness-of-fit test for the extended Gompertz growth model based on the instantaneous maturity rate. We have checked the performance of the test through simulation studies as well as real data. AMS 2010 subject classifications: 62Mxx, 92Bxx, 62P10

A Novel Unification Method to Characterize a Broad Class of Growth Curve Models Using Relative Growth Rate

2019 ◽  
Vol 81 (7) ◽  
pp. 2529-2552
Author(s):  
Biman Chakraborty ◽  
Amiya Ranjan Bhowmick ◽  
Joydev Chattopadhyay ◽  
Sabyasachi Bhattacharya
Keyword(s):  
Growth Rate ◽  
Relative Growth Rate ◽  
Growth Curve ◽  
Broad Class ◽  
Relative Growth ◽  
Growth Curve Models

scholarly journals Growth-related life-history traits of an invasive gammarid species: evaluation with a Laird–Gompertz model

2003 ◽  
Vol 81 (12) ◽  
pp. 2006-2014 ◽  
Author(s):  
Christophe Piscart ◽  
Simon Devin ◽  
Jean-Nicolas Beisel ◽  
Jean-Claude Moreteau
Keyword(s):  
Growth Rate ◽  
Growth Curve ◽  
Environmental Conditions ◽  
Sexual Maturity ◽  
Growth Models ◽  
Gompertz Model ◽  
Biological Traits ◽  
Freshwater Species ◽  
Dikerogammarus Villosus ◽  
Forcing Function

Although the invasive gammarid Dikerogammarus villosus (Crustacea, Amphipoda) is a recent successful invader of Western Europe's lakes and rivers and a threat to North American aquatic ecosystems, its biology is scarcely known. Different growth models for each sex were established for the first time for a natural population of a freshwater gammarid. The Laird–Gompertz growth curve was used because it best fit our data, and it was associated with an environmental forcing function to adjust the growth rate according to seasonal variations in environmental conditions. The growth curve was applied to a length decomposition obtained using the Bhattacharya method, realised on data obtained from a 1-year population dynamics study. The models allowed an assessment of biological traits such as life-span, the age of sexual maturity, the potential number of generations per year, and the growth rate as a function of environmental conditions. Differences in growth rate between males and females were consistent with biological processes such as allocation of energy for reproduction. Dikerogammarus villosus had higher rates of growth and earlier sexual maturity than all other taxa studied, which may explain its invasive tendencies and its ability to colonize numerous new ecosystems, thus becoming a cosmopolitan freshwater species.

scholarly journals Bio-safety assessment of nanozeolites of varying size and doses on soil beneficial microorganisms

2021 ◽  
Vol 42 (4(SI)) ◽  
pp. 1181-1190
Author(s):  
L. Sivashankari ◽  
◽  
S.K. Rajkishore ◽  
A. Lakshmanan ◽  
K.S. Subramanian ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Curve ◽  
Rhizobium Leguminosarum ◽  
Linear Growth ◽  
Trichoderma Viride ◽  
Growth Dynamics ◽  
Linear Growth Rate ◽  
Beneficial Microorganisms ◽  
Randomized Design ◽  
Poison Food Technique

Aim: To evaluate the toxic effects of nano-zeolites on soil beneficial microorganisms. Methodology: This study involved dry milling of zeolites at varying parameters to obtain dry-milled zeolites of four size regimes such as 10-100 nm, 200-400 nm, 500-1000 nm and 1000-2000 nm that were tested at incremental concentrations such as 100 ppm, 1000 ppm and 2000 ppm along with control on various soil beneficial microorganisms. Three replications were done for each treatment with factorial completely randomized design. The poison food technique, growth curve assessment followed by cytotoxicity and genotoxicity studies on all four bacterial genera treated with zeolites of varying sizes and doses were undertaken. The effects of zeolite on average linear growth rate (ALGR) of biocontrol agent, Trichoderma viride were also studied. Results: The effect of zeolites tested on four bacterial genera viz. Azotobacter chroococcum, Rhizobium leguminosarum, Bacillus megaterium and Pseudomonas fluorescens using poison food technique and growth curve revealed that zeolites regardless of size or concentration had positively influenced the growth dynamics of all four bacteria tested. The effect of zeolite on average linear growth rate (ALGR) of Trichoderma viride also indicated that incremental dose of zeolite had a positive effect. Lactose dehydrogenase revealed that 2000 ppm nano-zeolite exhibited cytotoxic effects on soil beneficial micro-organisms tested. On the other hand, comet assay demonstrated no quantifiable DNA damage in nano-zeolite treated cells in comparison to control cultures. Interpretation: This study unequivocally demonstrated that zeolites of size greater than 200-400 nm, irrespective of doses even up to 2000 ppm are quite safe for soil beneficial microbes.

scholarly journals Modeling of Nigeria’s Economic Growth Rate: A Probability Distribution Fitting Approach

2018 ◽  
pp. 1-17
Author(s):  
Eke, Charles N ◽  
Osuji, George Amaeze ◽  
Nwosu, Dozie Felix
Keyword(s):  
Economic Growth ◽  
Growth Rate ◽  
Probability Distribution ◽  
Goodness Of Fit ◽  
Laplace Distribution ◽  
Information Criteria ◽  
Logistic Distribution ◽  
Goodness Of Fit Test ◽  
Economic Growth Rate ◽  
Generalized Logistic Distribution

This study examined the probability distribution that best described the quarterly economic growth rate of Nigeria between 1960- 2015. The study collected secondary data from Central Bank of Nigeria (CBN) Statistical Bulletin 2015 on Gross Domestic Product to compute the economic growth rate of Nigeria. Six theoretical statistical distributions were fitted via Normal Distribution, Logistic Distribution, Laplace Distribution, Cauchy Distribution, Gumbel (Largest Extreme Value) Distribution and Generalized Logistic Distribution. The Laplace Distribution fitted the data as confirmed by Kolmogorov Simonov goodness of fit test, Akaike Information Criteria and Bayes Information Criteria. The probabilities of economic growth rate behaviours were obtained from the best fit distribution. The analysis showed that the chance of obtaining a negative quarterly economic growth rate is 28%. The chance of an economic recession is 8%. Also, the probability of having a positive single digit quarterly economic growth rate is 46%. In addition, having a double digit positive quarterly economic growth rate is 26%.  

STABILITY OF INFORMATION GRANULATION AND INFORMATION GRANULES

2002 ◽  
Vol 02 (02) ◽  
pp. 221-238
Author(s):  
WITOLD PEDRYCZ ◽  
GEORGE VUKOVICH
Keyword(s):  
Experimental Evidence ◽  
Statistical Inference ◽  
Real World ◽  
Goodness Of Fit ◽  
Broad Class ◽  
Experimental Studies ◽  
Goodness Of Fit Test ◽  
Information Granules ◽  
Information Granulation ◽  
Nonparametric Testing

In this study, we introduce a notion of stability of information granules. Granulation of information results in a series of chunks of information usually referred to as information granules. Information granules are basic building entities involved in the formation of a broad class of systems. Information granules are percepts — entities being perceived by humans as being essential when working with some real-world phenomena, especially describing and interacting with them. The percepts need to be comprehensible. They should also reflect the experimental evidence. All in all, they should be stable meaning that they are conceptual entities that reconcile experimental reality with the subjective and ultimately observer-based judgment about the environment. Once being stable, information granules could be viewed as architecture-independent. The proposed algorithmic environment supporting this concept dwells on the ideas of statistical inference that helps quantify stability through a nonparametric testing. The χ2 goodness-of-fit test is used here as a validation mechanism. First, the study elaborates on the formation of information granules and concentrates on the descriptive and prescriptive ways of their design. In the sequel, it is revealed how these two ways interact with the construction of stable information granules. A number of experimental studies are also included.

Describing and predicting potential growth in the pig

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

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

Validation of the CASUS score in Tunisian patients: a quality management tool in intensive care units

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
T Besbes ◽  
S Mleyhi ◽  
J Sahli ◽  
M Messai ◽  
J Ziadi ◽  
...  
Keyword(s):  
Cardiac Surgery ◽  
Roc Curve ◽  
Goodness Of Fit ◽  
Cardiovascular Surgery ◽  
Management Tool ◽  
Medical Decision ◽  
Tunisian Population ◽  
Correct Classification ◽  
Goodness Of Fit Test ◽  
A Value

Abstract Background Early prediction of patients at highest risk of a poor outcome after cardiovascular surgery, including death can aid medical decision making, and adapt health care management in order to improve prognosis. In this context, we conducted this study to validate the CASUS severity score after cardiac surgery in the Tunisian population. Methods This is a retrospective cohort study conducted among patients who underwent cardiac surgery under extracorporeal circulation during the year 2018 at the Cardiovascular Surgery Department of La Rabta University Hospital in Tunisia. Data were collected from the patients hospitalization records. The discrimination of the score was assessed using the ROC curve and the calibration using the Hosmer-Lemeshow goodness of fit test and then by constructing the calibration curve. Overall correct classification was also obtained. Results In our study, the observed mortality rate was 10.52% among the 95 included patients. The discriminating power of the CASUS score was estimated by the area under the ROC curve (AUC), this scoring system had a good discrimination with AUC greater than 0.9 from postoperative Day 0 to Day 5.From postoperative day 0 to day 5, the Hosmer-Lemeshow's test gave a value of chi square test statistic ranging from 1.474 to 8.42 and a value of level of significance ranging from 0.39 to 0.99 indicating a good calibration. The overall correct classification rate from postoperative day 0 to day 5 ranged from 84.4% to 92.4%. Conclusions Despite the differences in the profile of the risk factors between the Tunisian population and the population constituting the database used to develop the CASUS score, we can say that this risk model presents acceptable performances in our population, attested by adequate discrimination and calibration. Prospective and especially multicentre studies on larger samples are needed before definitively conclude on the performance of this model in our country. Key messages The casus score seems to be valid to predict mortality among patients undergoing cardiac surgery. Multicenter study on larger sample is needed to derive and validate models able to predict in-hospitals mortality.

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