scholarly journals the use of diameter distributions for determining optimum holding length for Gmelina arborea plantations in a Nigerian lowland rainforest

2008 ◽  
Vol 6 (2) ◽  
Author(s):  
S Ajayi ◽  
O Olajide ◽  
I B Adinya
Keyword(s):  
Gmelina Arborea ◽  
Lowland Rainforest ◽  
Diameter Distributions

Modeling diameter distributions of Gmelina arborea plantation in Omo Forest Reserve, Nigeria with Johnson’s SB

2016 ◽  
Vol 36 (2) ◽  
pp. 121-133 ◽  
Author(s):  
Friday N. Ogana ◽  
Ekaette S. Itam ◽  
Johnson S. A. Osho
Keyword(s):  
Gmelina Arborea ◽  
Forest Reserve ◽  
Diameter Distributions

The Influence of Reaction Temperature on the Size of the Catalyst Nano-particle and the Carbon Nanotube Diameter Distributions

2008 ◽  
Author(s):  
Enkeleda Dervishi ◽  
Zhongrui Li ◽  
Fumiya Watanabe ◽  
Yang Xu ◽  
Viney Saini ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Reaction Temperature ◽  
Nano Particle ◽  
Diameter Distributions

ACCEPTABILITY AND UTILIZATION OF GRADED LEVELS OF GMELINA ARBOREA AND CASSAVA PEELS CONCENTRATES IN WEST AFRICAN DWARF SHEEP

2015 ◽  
Vol 4 (2) ◽  
pp. 415-422
Author(s):  
Amoka Pius ◽  
Tawose O M
Keyword(s):  
Dry Matter ◽  
Nutritive Value ◽  
Control Diet ◽  
Nutrient Digestibility ◽  
Dry Matter Intake ◽  
Gmelina Arborea ◽  
Leaf Meal ◽  
Dry Matter Digestibility ◽  
Inclusion Level ◽  
Cassava Peels

The nutritive value ,voluntary dry matter intake, and the nutrient digestibility of graded levels of Gmelina arborea and cassava peels concentrates in WAD sheep was investigated. Twelve WAD sheep aged 1-2 years old and weighting 14.00± 0.45 kg were used in a complete randomized design. Diets were formulated such that cassava peels was replaced with Gmelina arborea leaf meal at 0, 33.33, 66.67, 100% levels, designated as diets A, B, C, and D respectively. Diet without Gmelina arborea leaf meal was tagged the control diet. The concentrate feed was compounded to contain 16% CP. Diets with 33.33% inclusion level of Gmelina arborea had significantly (P<0.05) higher dry matter intake (DMI) 598.80g day-1, while the lowest DMI 425.00g day-1 was obtained in animals fed 100% inclusion level of Gmelina arborea. Crude protein intake (CPI) of animals fed diets with 33.33% inclusion levels of Gmelina arborea were significantly (P<0.05) highest, followed by 66.67% inclusion level and the least was observed in 0% inclusion level of Gmelina arborea. Dry matter digestibility (DMD) was significantly (P<0.05) different across the dietary treatments, animals placed on diets with 33.33% inclusion level had the highest DMD, followed by animals on diets with 66.67, 100 and 0% inclusion levels. CP digestibility (P<0.05) increased from 33.33% to 100% inclusion levels of Gmelina arborea leaf meal, the lowest CP digestibility was observed at 0% inclusion level. CF digestibility (P<0.05) increased from 33.33% to 100% inclusion levels of Gmelina arborea leaf meal, while the lowest CF digestibility was observed at 0% inclusion level. N intake increased significantly (P<0.05) with increase in the level of Gmelina arborea inclusion from 33.33% to 100%. N retention was significantly (P<0.05) different, diets with 33.33% Gmelina arborea inclusion had the highest value (64.36g day-1) followed by 66.67%, 100% and the least (52.64g day-1) was at 0% inclusion level of Gmelina arborea.  N balance values also followed the same trend. From the results of this study, it can be concluded that the inclusion of Gmelina arborea leaf meal in WAD rams diet was well tolerated without adverse effect on acceptability, intake and nutrient digestibility, and inclusion level of 33.33% is hereby recommended in ruminants diet for optimum performance and productivity.

ÍNDICE DE SITIO Y PRODUCCIÓN MADERABLE EN PLANTACIONES FORESTALES DE Gmelina arborea EN TABASCO, MÉXICO

2015 ◽  
Vol 38 (4) ◽  
pp. 415
Author(s):  
Pablo Martínez-Zurimendi ◽  
Marivel Domínguez-Domínguez ◽  
Alfonso Juárez-García ◽  
Leydi M. López-López ◽  
Verónica De-la-Cruz-Arias ◽  
...  
Keyword(s):  
Von Bertalanffy ◽  
Gmelina Arborea ◽  
O 19

El índice de sitio es una representación gráfica de la capacidad productiva de un área forestal, que describe la relación entre la altura dominante y la edad de un rodal (bosquete de características homogéneas), o árbol individual de una especie determinada. En este estudio se ajustaron los modelos de crecimiento de Von Bertalanffy, Chapman, Monomolecular, Logístico, Gompertz, Weibull, Hossfeld IV, Levakovic III, Korf y Sloboda para generar curvas anamórficas de índice de sitio para Gmelina arborea Roxb., con base en datos edad-altura dominante obtenidos de mediciones y remediciones en parcelas de muestreo de plantaciones forestales comerciales en el estado de Tabasco, México. Se utilizó el método de la curva guía; los parámetros de crecimiento de los modelos ajustados se obtuvieron con SAS, mediante regresión no lineal. De acuerdo con la bondad de ajuste, el análisis de residuales y su validación con la eficiencia, el error medio del modelo y la diferencia absoluta media, seis modelos resultaron satisfactorios. Se determinaron cinco curvas de índices de sitio con edad base de 10 años, las cuales se clasificaron en mala (14.5 m), regular (19.5 m), buena (24.5 m), muy buena (29.5 m) y excelente (34.5 m). Se ajustaron ecuaciones que cuantifican el índice de sitio en función del área basal y la edad de la plantación, útiles para definir la calidad de sitio hasta que la plantación alcance 5 años de edad o 19 m2 ha-1 de área basal. Se identificaron modelos de la evolución del diámetro medio cuadrático y el volumen de madera en las plantaciones en función de la edad, y el valor generado de índice de sitio. Estos modelos servirán para predecir la producción de madera (m3 ha-1/año) y el turno en el que se alcanzará un diámetro de corta determinado, en función del índice de sitio.

scholarly journals A distribution-centered approach for analyzing human adipocyte size estimates and their association with obesity-related traits and mitochondrial function

2021 ◽  
Author(s):  
Julius Honecker ◽  
Dominik Weidlich ◽  
Simone Heisz ◽  
Cecilia M. Lindgren ◽  
Dimitrios C. Karampinos ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Mitochondrial Respiration ◽  
Mitochondrial Respiratory Chain ◽  
Cell Diameter ◽  
Adipocyte Size ◽  
Fat Cell ◽  
Positive Correlations ◽  
Size Estimates ◽  
Diameter Distributions ◽  
Mitochondrial Respiratory

Abstract Objective Cell diameter, area, and volume are established quantitative measures of adipocyte size. However, these different adipocyte sizing parameters have not yet been directly compared regarding their distributions. Therefore, the study aimed to investigate how these adipocyte size measures differ in their distribution and assessed their correlation with anthropometry and laboratory chemistry. In addition, we were interested to investigate the relationship between fat cell size and adipocyte mitochondrial respiratory chain capacity. Methods Subcutaneous and visceral histology-based adipocyte size estimates from 188 individuals were analyzed by applying a panel of parameters to describe the underlying cell population. Histology-based adipocyte diameter distributions were compared with adipocyte diameter distributions from collagenase digestion. Associations of mean adipocyte size with body mass index (BMI), glucose, HbA1C, blood lipids as well as mature adipocyte mitochondrial respiration were investigated. Results All adipocyte area estimates derived from adipose tissue histology were not normally distributed, but rather characterized by positive skewness. The shape of the size distribution depends on the adipocyte sizing parameter and on the method used to determine adipocyte size. Despite different distribution shapes histology-derived adipocyte area, diameter, volume, and surface area consistently showed positive correlations with BMI. Furthermore, associations between adipocyte sizing parameters and glucose, HbA1C, or HDL specifically in the visceral adipose depot were revealed. Increasing subcutaneous adipocyte diameter was negatively correlated with adipocyte mitochondrial respiration. Conclusions Despite different underlying size distributions, the correlation with obesity-related traits was consistent across adipocyte sizing parameters. Decreased mitochondrial respiratory capacity with increasing subcutaneous adipocyte diameter could display a novel link between adipocyte hypertrophy and adipose tissue function.

Vertical stratification and seasonal changes of the avian community in Mount Cameroon lowland rainforest

2021 ◽  
Author(s):  
Kryštof Chmel ◽  
Solange Mekuate Kamga ◽  
Taku Awa ◽  
Francis Luma Ewome ◽  
Guillermo Uceda‐Gómez ◽  
...  
Keyword(s):  
Seasonal Changes ◽  
Vertical Stratification ◽  
Avian Community ◽  
Mount Cameroon ◽  
Lowland Rainforest

scholarly journals Modeling Diameter Distributions with Six Probability Density Functions in Pinus halepensis Mill. Plantations Using Low-Density Airborne Laser Scanning Data in Aragón (Northeast Spain)

2021 ◽  
Vol 13 (12) ◽  
pp. 2307
Author(s):  
J. Javier Gorgoso-Varela ◽  
Rafael Alonso Ponce ◽  
Francisco Rodríguez-Puerta
Keyword(s):  
Probability Density ◽  
Linear Models ◽  
Pinus Halepensis ◽  
Beta Function ◽  
Probability Density Functions ◽  
Lidar Data ◽  
Density Functions ◽  
Minimum Diameter ◽  
Location Parameters ◽  
Diameter Distributions

The diameter distributions of trees in 50 temporary sample plots (TSPs) established in Pinus halepensis Mill. stands were recovered from LiDAR metrics by using six probability density functions (PDFs): the Weibull (2P and 3P), Johnson’s SB, beta, generalized beta and gamma-2P functions. The parameters were recovered from the first and the second moments of the distributions (mean and variance, respectively) by using parameter recovery models (PRM). Linear models were used to predict both moments from LiDAR data. In recovering the functions, the location parameters of the distributions were predetermined as the minimum diameter inventoried, and scale parameters were established as the maximum diameters predicted from LiDAR metrics. The Kolmogorov–Smirnov (KS) statistic (Dn), number of acceptances by the KS test, the Cramér von Misses (W2) statistic, bias and mean square error (MSE) were used to evaluate the goodness of fits. The fits for the six recovered functions were compared with the fits to all measured data from 58 TSPs (LiDAR metrics could only be extracted from 50 of the plots). In the fitting phase, the location parameters were fixed at a suitable value determined according to the forestry literature (0.75·dmin). The linear models used to recover the two moments of the distributions and the maximum diameters determined from LiDAR data were accurate, with R2 values of 0.750, 0.724 and 0.873 for dg, dmed and dmax. Reasonable results were obtained with all six recovered functions. The goodness-of-fit statistics indicated that the beta function was the most accurate, followed by the generalized beta function. The Weibull-3P function provided the poorest fits and the Weibull-2P and Johnson’s SB also yielded poor fits to the data.

A Blind Spot in the Use of the Weibull Function for Modeling Diameter Distributions

2020 ◽  
Author(s):  
Adrian Norman Goodwin
Keyword(s):  
Lower Bound ◽  
Blind Spot ◽  
Forest Growth ◽  
Growth And Yield ◽  
Diameter Distribution ◽  
Absolute Difference ◽  
Weibull Function ◽  
Distribution Models ◽  
Difference Statistic ◽  
Diameter Distributions

Abstract Diameter distribution models based on probability density functions are integral to many forest growth and yield systems, where they are used to estimate product volumes within diameter classes. The three-parameter Weibull function with a constrained nonnegative lower bound is commonly used because of its flexibility and ease of fitting. This study compared Weibull and reverse Weibull functions with and without a lower bound constraint and left-hand truncation, across three large unthinned plantation cohorts in which 81% of plots had negatively skewed diameter distributions. Near-optimal lower bounds for the unconstrained Weibull function were negative for negatively skewed data, and the left-truncated Weibull using these bounds was 14.2% more accurate than the constrained Weibull, based on the Kolmogorov-Smirnov statistic. The truncated reverse Weibull fit dominant tree distributions 23.7% more accurately than the constrained Weibull, based on a mean absolute difference statistic. This work indicates that a blind spot may have developed in plantation growth modeling systems deploying constrained Weibull functions, and that left-truncation of unconstrained functions could substantially improve model accuracy for negatively skewed distributions.

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