scholarly journals US Nobel laureates: Logistic growth versus Volterra–Lotka

2021 ◽  
Author(s):  
THEODORE MODIS
Keyword(s):  
Data Fitting ◽  
Logistic Growth ◽  
Growth Equation ◽  
Cumulative Data ◽  
Nobel Laureates ◽  
S Curve ◽  
Special Case

The logistic-growth equation is a special case of the Volterra-Lotka equations. The former describes competition only between members of the same species whereas the latter describes competition also with other species. In the study of US Nobel laureates considering laureates per population improves the quality of the logistic fit but the Volterra-Lotka approach suggests that a logistic description would be a good approximation for data per unit of time rather than cumulative data. Fitting logistic S curves on cumulative data — although proven successful in many business and other applications — constitutes treacherous terrain for inexperienced S-curve enthusiasts. The Volterra-Lotka analysis of Nobel laureates reveals other insights such as that Americans and other nationalities are locked in a win-win struggle with Americans drawing more of a benefit, and also that American Nobel laureates “incubate” new Nobel laureates to a lesser extent than other nationalities.

Progress curve analysis of qRT-PCR reactions using the logistic growth equation

2011 ◽  
Vol 27 (5) ◽  
pp. 1407-1414 ◽  
Author(s):  
Meile Liu ◽  
Claudia Udhe-Stone ◽  
Chetan T. Goudar
Keyword(s):  
Curve Analysis ◽  
Logistic Growth ◽  
Growth Equation ◽  
Qrt Pcr ◽  
Progress Curve

scholarly journals Simulation Tools for Small Area Estimation: Introducing the R-package saeSim

2016 ◽  
Vol 45 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Sebastian Warnholz ◽  
Timo Schmid
Keyword(s):  
Small Area ◽  
Small Area Estimation ◽  
R Package ◽  
Research Process ◽  
Simulation Studies ◽  
Simulation Tools ◽  
Area Estimation ◽  
Regional Estimates ◽  
Special Case

The demand for reliable regional estimates from sample surveys has been substantially grown over the last decades. Small area estimation provides statistical methods to produce reliable predictions when the sample sizes in regions are too small to apply direct estimators. Model- and design-based simulations are used to gain insights into the quality of the introduced methods. In this article we present a framework which may help to guarantee the reproducibility of simulation studies in articles and during research. The introduced R-package saeSim is adjusted to provide a simulation environment for the special case of small area estimation. The package may allow the prospective researcher during the research process to produce simulation studies with a minimal eort of coding.

scholarly journals Psi-Caputo Logistic Population Growth Model

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Muath Awadalla ◽  
Yves Yannick Yameni Noupoue ◽  
Kinda Abu Asbeh
Keyword(s):  
Population Growth ◽  
Fractional Derivative ◽  
Carrying Capacity ◽  
Chinese Population ◽  
Logistic Model ◽  
Logistic Equation ◽  
Logistic Growth ◽  
Growth Equation ◽  
Uniqueness Of The Solution ◽  
Better Than

This article studies modeling of a population growth by logistic equation when the population carrying capacity K tends to infinity. Results are obtained using fractional calculus theories. A fractional derivative known as psi-Caputo plays a substantial role in the study. We proved existence and uniqueness of the solution to the problem using the psi-Caputo fractional derivative. The Chinese population, whose carrying capacity, K, tends to infinity, is used as evidence to prove that the proposed approach is appropriate and performs better than the usual logistic growth equation for a population with a large carrying capacity. A psi-Caputo logistic model with the kernel function x + 1 performed the best as it minimized the error rate to 3.20% with a fractional order of derivative α  = 1.6455.

A Neoclassical Growth Model for Population Dynamics in a Homogeneous Habitat

2001 ◽  
Author(s):  
Peter Vadasz ◽  
Alisa S. Vadasz
Keyword(s):  
Experimental Data ◽  
Growth Model ◽  
Logistic Growth ◽  
Lag Phase ◽  
Growth Stages ◽  
Initial Growth ◽  
Neoclassical Model ◽  
Wide Range ◽  
Logistic Growth Model ◽  
Special Case

Abstract A neoclassical model is proposed for the growth of cell and other populations in a homogeneous habitat. The model extends on the Logistic Growth Model (LGM) in a non-trivial way in order to address the cases where the Logistic Growth Model (LGM) fails short in recovering qualitative as well as quantitative features that appear in experimental data. These features include in some cases overshooting and oscillations, in others the existence of a “Lag Phase” at the initial growth stages, as well as an inflection point in the “In curve” of the population size. The proposed neoclassical model recovers also the Logistic Growth Curve as a special case. Comparisons of the solutions obtained from the proposed neoclassical model with experimental data confirm its quantitative validity, as well as its ability to recover a wide range of qualitative features captured in experiments.

Educational Leadership for Enhancing Quality in Teacher Education

2016 ◽  
pp. 1632-1654
Author(s):  
Neeta Baporikar
Keyword(s):  
Teacher Education ◽  
Educational Leadership ◽  
Business Leader ◽  
Separate Entity ◽  
Educational Leader ◽  
Educational Aims ◽  
Theories Of Leadership ◽  
Special Case ◽  
Central Purpose

Educational leadership refers to the process of soliciting and managing the capacities and vitalities of teachers, pupils and parents toward achieving common educational aims. Educational leadership also refers to an individual or group of people who are in charge and lead schools, institutions, programmes and students. The development of leadership as a separate entity goes some way in arguing that an effective educational leader will share much of the same characteristics as a successful business leader. If one sees leadership as a distinct vocation, then one can see that many of the skills and traits are transferable. However, education is a special case, because teaching students has to be the central purpose that educational leadership must reflect. Hence, even if it is drawn from various existent theories of leadership, yet the success is dependent on how much it would enhance the quality of teacher education. The overall mission of this valuable study is to aid researchers in recognizing and understanding the need of educational leadership for enhancing the quality of teacher education.

scholarly journals Variation in Marginal Response to Nitrogen Fertilizer between Locations

2000 ◽  
Vol 32 (2) ◽  
pp. 363-372 ◽  
Author(s):  
Dale K. Graybeal
Keyword(s):  
North Carolina ◽  
Nitrogen Fertilizer ◽  
Logistic Growth ◽  
Growth Equation ◽  
Finite Sample ◽  
Dummy Variable ◽  
Bootstrap Simulation ◽  
Sample Covariance ◽  
The Mean ◽  
Parameter Values

AbstractA logistic growth equation with time and location varying parameters was used to model corn response to applied nitrogen. A nonlinear dummy-variable regression model provided a parsimonious representation of site and time effects on parameter values. The model was used to test for the equality of the mean marginal product of nitrogen fertilizer between locations on the coastal plain of North Carolina. Monte Carlo simulation and bootstrap simulation were used to construct finite sample covariance estimates. Results support rejection of the hypothesis that mean marginal products are equal when nitrogen is applied at 168 kg/ac. A comparison of bootstrapped errors and asymptotic errors suggests that results based on asymptotic theory are fairly reliable in this case.

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 Long-Term GDP Forecasts and the Prospects for Growth

2021 ◽  
Author(s):  
THEODORE MODIS
Keyword(s):  
Gdp Per Capita ◽  
Logistic Growth ◽  
Growth Equation ◽  
Industrialized Countries ◽  
Real Gdp ◽  
Term Forecast ◽  
The Us ◽  
Real Gdp Per Capita ◽  
Per Capita

The growth of GDP is considered as a natural-growth process amenable to description by the logistic-growth equation. The S-shaped logistic pattern provides good descriptions and forecasts for both nominal and real GDP per capita in the US over the last 80 years. This enables the calculation of a long-term forecast for inflation, which is to enter a declining trend not so far in the future. The two logistics are well advanced, more so for nominal GDP. The assumption for logistic growth works even better for Japan whose nominal GDP per capita has already completed tracing out an entire logistic trajectory. The economic woes of industrialized countries could be attributed to the saturation of growth there, as if a niche in nature had been filled to capacity. In contrast, GDP growth in China and India is in the very early stages of logistic growth still indistinguishable from exponential patterns. The ceiling of these logistics can be anywhere between 7 and 15 times today’s levels.

ON THE GOMPERTZ LIMIT OF THE MONOTONIC NEOCLASSICAL GROWTH MODEL

2009 ◽  
Vol 09 (01) ◽  
pp. 63-80 ◽  
Author(s):  
PETER VADASZ ◽  
ALISA S. VADASZ
Keyword(s):  
Growth Model ◽  
Burden Of Proof ◽  
Logistic Growth ◽  
Neoclassical Growth Model ◽  
Convex Curves ◽  
Biological Reality ◽  
Quantitative Validation ◽  
Special Case ◽  
Physical Principles ◽  
Neoclassical Growth

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.

Pattern analysis of a grazing experiment

1971 ◽  
Vol 22 (2) ◽  
pp. 245 ◽  
Author(s):  
WT Williams ◽  
P Gillard
Keyword(s):  
Pattern Analysis ◽  
Spatial Configuration ◽  
Systematic Change ◽  
Complex Data ◽  
Progressive Reduction ◽  
Plausible Hypothesis ◽  
Canonical Coordinate ◽  
Special Case

The complementary functions of pattern analysis and statistical analysis are discussed, with particular reference to the analysis of agricultural experiments. It is suggested that pattern analysis, in addition to its usual function of simplification of complex data, may contribute to the analysis of grazing experiments in the special case in which there is reason to suspect the existence of an external non-random environmental factor. Such a case is analysed completely; it is shown that the existence of such a factor can be established by intrinsic classification of entire liveweight sequences. The factor can then be partitioned out by principal coordinate analysis; its spatial configuration can be elucidated, and the extent of its contribution to the overall results assessed. Its optimum correlation with parallel botanical data can be established by canonical coordinate analysis. It is then possible to formulate causative hypotheses as to the nature of the factor; in the present case the most plausible hypothesis was that a small systematic change in tree density caused a progressive reduction in quantity and quality of herbage as we passed from the centre of the area to the periphery. This hypothesis could be used for further experiment and statistical test. Standard programmes for the entire analysis exist on the Control Data 3600 computer at Canberra.

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