Statistical analysis of an alternative von Bertalanffy model for tree growth

2014 ◽  
Vol 2 (3) ◽  
pp. 157-163 ◽  
Author(s):  
S. O. Oyamakin ◽  
A. U. Chukwu
Keyword(s):  
Statistical Analysis ◽  
Tree Growth ◽  
Von Bertalanffy ◽  
Von Bertalanffy Model

scholarly journals Growth of the tambaqui Colossoma macropomum (Cuvier) (Characiformes: Characidae): which is the best model?

2005 ◽  
Vol 65 (1) ◽  
pp. 129-139 ◽  
Author(s):  
M. A. H Penna ◽  
M. A Villacorta-Corrêa ◽  
T. Walter ◽  
M. Petrere-JR
Keyword(s):  
Growth Model ◽  
Negative Correlation ◽  
The Other ◽  
Data Sources ◽  
Von Bertalanffy ◽  
Data Set ◽  
Colossoma Macropomum ◽  
Von Bertalanffy Model ◽  
Estimated Parameters ◽  
Schnute Model

In order to decide which is the best growth model for the tambaqui Colossoma macropomum Cuvier, 1818, we utilized 249 and 256 length-at-age ring readings in otholiths and scales respectively, for the same sample of individuals. The Schnute model was utilized and it is concluded that the Von Bertalanffy model is the most adequate for these data, because it proved highly stable for the data set, and only slightly sensitive to the initial values of the estimated parameters. The phi' values estimated from five different data sources presented a CV = 4.78%. The numerical discrepancies between these values are of not much concern due to the high negative correlation between k and L<FONT FACE=Symbol>¥</FONT> viz, so that when one of them increases, the other decreases and the final result in phi' remains nearly unchanged.

Age, growth and mortality of the garfish, Belone belone (L. 1761) in the Adriatic Sea

2012 ◽  
Vol 93 (2) ◽  
pp. 365-372 ◽  
Author(s):  
Barbara Zorica ◽  
Vanja Čikeš Keč
Keyword(s):  
Adriatic Sea ◽  
Growth Parameters ◽  
Fork Length ◽  
Mortality Rates ◽  
Von Bertalanffy ◽  
Positive Allometry ◽  
Von Bertalanffy Model ◽  
Total Length ◽  
Belone Belone ◽  
Conservation And Management

A sample of 3393 garfish, Belone belone (Linnaeus, 1761) was captured using a seine net between January 2003 and December 2008, along the eastern Adriatic Sea. The range in total length was 20.8–75.4 cm and in weight was 12.21–639.25 g. Length–length equations for converting size measurements (standard length and fork length to total length (TL)) were linear. In the length–weight relationship, positive allometry was established (b = 3.4818). Age, determined from sagittal otoliths, ranged from 1+ to 8+ years. The estimated von Bertalanffy model growth parameters for garfish were L∞ = 90.3 cm, K = 0.158 year−1, t0 = −0.109. Otolith weight was endorsed as a possible age predictor, as it showed highly exponential correlation with total garfish length and age (Wo = 0.0012 TL2.189; Wo = 0.568t1.486). These findings were used to examine mortality rates and exploitation in order to improve conservation and management of this pelagic species.

scholarly journals Structure and population dynamics of the secondary burrower crayfish Procambarus acanthophorus from a tropical Mexican wetland

2016 ◽  
Vol 94 (7) ◽  
pp. 479-488
Author(s):  
J.A. Viccon-Pale ◽  
P. Ortega ◽  
L. Mendoza-Vargas ◽  
P. Castilla-Hernández ◽  
A. López-Cuevas ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Sex Ratio ◽  
Growth Parameters ◽  
Von Bertalanffy ◽  
Frequency Distributions ◽  
Structure And Dynamics ◽  
Von Bertalanffy Model ◽  
Cephalothorax Length ◽  
Flood Period ◽  
Class Dynamic

Catch size, sex ratio, structure and dynamics, as well as mortality, of a population of the secondary burrower crayfish Procambarus acanthophorus Villalobos, 1948, from tropical wetland La Mixtequilla, Veracruz, Mexico, were examined. Monthly samples were taken from artisanal commercial captures. A total of 2141 individuals were caught. Although the total female:male ratio was 0.86, variation in sex ratios have also been found in monthly catches. Monthly polymodal frequency distributions of cephalothorax length (CL) were analyzed by the Bhattacharya method. Population catches consisted of six CL classes. The CL-class dynamic may show adaptations to the flood period. Growth parameters were estimated using the von Bertalanffy model. For females, K = 0.39 year−1, CL∞ = 57.30 mm, [Formula: see text] = 3.11, and tmax = 6.73 years were found; it is appropriate that for males, K = 0.40 year−1, CL∞ = 59.00 mm, [Formula: see text] = 3.14, and tmax = 6.59 years were found. We also examined whether water temperature influences the catches or sex ratio.

Growth and reproductive parameters of Kalliapseudes schubartii in the estuarine region of the Lagoa dos Patos (southern Brazil)

2003 ◽  
Vol 83 (5) ◽  
pp. 931-935 ◽  
Author(s):  
Duane B. Fonseca ◽  
Fernando D'Incao
Keyword(s):  
Reproductive Activity ◽  
Individual Growth ◽  
Von Bertalanffy ◽  
Reproductive Parameters ◽  
Southern Brazil ◽  
Relative Growth ◽  
Von Bertalanffy Model ◽  
Soft Bottoms ◽  
Estuarine Region ◽  
Growth And Reproduction

Kalliapseudes schubartii (Crustacea: Tanaidacea) is a tube dwelling invertebrate living in estuarine soft bottoms with distribution along the south-east and southern Brazilian and Uruguayan coasts. Individual growth, and reproduction were examined by taking samples for a year in the estuarine region of the Lagoa dos Patos (southern Brazil). The von Bertalanffy model described growth of K. schubartii (K=4.54 y−1, L∞=13.22 mm). Reproductive activity was observed in spring and summer. No relationship was observed between total length of females and brood size. Eggs, embryos, and mancas were often observed in a marsupium. Relative growth analysis showed two levels of allometry in the growth of chelipeds of males.

scholarly journals Sexuality Communication between the Clergy and Adolescents in Nakuru County, Kenya.

2020 ◽  
Vol 2 (1) ◽  
pp. 178-188
Author(s):  
Francis Ndegwa; Eliud Kirigia; Pauline Ndoro; Vicky Khasandi
Keyword(s):  
Statistical Analysis ◽  
Secondary Schools ◽  
Sexual Communication ◽  
Feedback Loops ◽  
Sensitive Information ◽  
Von Bertalanffy ◽  
Same Sex ◽  
Sexuality Communication ◽  
Rural Teacher ◽  
Self Administered Questionnaire

The study examines the sexuality communication between the clergy and adolescents in Nakuru County, Kenya. The study uses Systems theory anchored by Ludwing Von Bertalanffy (1969). Eighty students were sampled from ten secondary schools in Nakuru East and Njoro sub-counties representing both urban and rural teacher population. The schools included six same-sex secondary (three only boys and three only girls) schools and four mixed-sex secondary schools. The categories of the schools included two national schools, three extra-county schools, three county schools and two sub-county schools. The study used a self-administered questionnaire as a method of data collection, which was appropriate for collecting sensitive information such as sexual communication yet provide quantifiable data that can be used for statistical analysis. The schools were categorized from letter A to J. The results of this study showed that although the clergy engage the adolescents in some sexuality communication, the sexuality information communicated by the clergy was insufficient to help them manage the sexuality challenges they encounter. This is partly because adolescents did not consider their interests as fully taken into account since the clergy used strategies that were convenient for them, but failed to address the adolescents’ needs. The study suggested that clergy should be more accommodative of the views of the adolescents by considering the feedback regarding their interests and concerns. A good system will seek balance through interchanging with its environment and this comes through those feedback loops that enlighten the system on how or what to modify in order to maintain the system balance.

The influence of drought on tree growth in Germany – from models to general statements

2015 ◽  
Vol 5 (3) ◽  
pp. 76-83
Author(s):  
Бек ◽  
Volfgang Bek ◽  
Нахтин ◽  
Marko Nakhtin ◽  
Мюллер ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Norway Spruce ◽  
Tree Ring ◽  
Tree Growth ◽  
Climate Scenario ◽  
European Beech ◽  
Decision Makers ◽  
Analysis Tool ◽  
Relative Increment ◽  
Statistical Analysis Tool

The scientific perspective on the climate-growth relationship is usually multivariate and too complex for decision makers, who need simpler statements. We analyse the relationships between the climate and tree growth with the help of 89 tree ring chronologies for Norway spruce, Scots pine and European beech in Germany. The statistical analysis tool CLIMTREG is used to discover climate-growth relationships and to model relative increment deviations caused by the force of climate scenario data.

scholarly journals Parâmetros genéticos de características estimadas da curva de crescimento de ovinos da raça Santa Inês

2006 ◽  
Vol 35 (3 suppl) ◽  
pp. 1012-1019 ◽  
Author(s):  
Raimundo Nonato Braga Lôbo ◽  
Luciana Cristine Vasques Villela ◽  
Ana Maria Bezerra Oliveira Lobo ◽  
José Renato de Sousa Passos ◽  
Amaury Apolonio de Oliveira
Keyword(s):  
Statistical Analysis ◽  
Von Bertalanffy ◽  
Statistical Analysis System ◽  
Santa Inês ◽  
Para Determinar ◽  
Analysis System

Este trabalho foi realizado com os objetivos de estudar o ajuste das funções de Richards, Brody, Gompertz, Von Bertalanffy e Logística sobre a curva de crescimento de ovinos Santa Inês e estimar parâmetros genéticos para características calculadas a partir da função de melhor ajuste. Foram utilizadas apenas informações de fêmeas controladas entre os anos de 1993 e 2004, na Embrapa Tabuleiros Costeiros, e entre 1981 e 2004, na Embrapa Caprinos. Para o ajuste das curvas, as análises foram realizadas separadamente para cada rebanho, utilizando-se o procedimento NLIN do software Statistical Analysis System (SAS), por meio do método de GAUSS. Para determinar a função que melhor ajustava os dados, foram utilizados os critérios de coeficiente de determinação (R²), de quadrado médio residual (QMR) e o erro de predição médio (EM). No rebanho da Embrapa Tabuleiros Costeiros, todas as funções subestimaram os pesos, à exceção da curva de Richards. Diferentemente, todas as funções superestimaram o peso predito para o rebanho da Embrapa Caprinos. A curva de Richards foi a que promoveu melhor ajuste nos dois rebanhos. Os valores do peso adulto e da taxa de maturação estimados pela função de Richards foram de 54,38 kg e 0,00144/dia, respectivamente, para o rebanho da Embrapa Tabuleiros Costeiros, e 42,74 kg e 0,00260/dia, respectivamente, para o da Embrapa Caprinos. A função de Richards foi utilizada para estimar curvas individuais de crescimento dos animais. A partir destas curvas, foram estimadas várias características de interesse econômico. Os parâmetros genéticos e os componentes de (co) variância para estas características foram estimados pelo método da Máxima Verossimilhança Restrita Livre de Derivadas (DFREML), utilizando-se o software MTDFREML. As estimativas de herdabilidades direta e materna variaram, respectivamente, de 0,01 a 0,99 e de 0,00 a 0,13. É possível alterar o padrão da curva de crescimento destes animais por meio de seleção.

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