scholarly journals Is the relationship between population density and body size consistent across independent studies? A meta-analytical approach

2001 ◽  
Vol 61 (1) ◽  
pp. 1-6 ◽  
Author(s):  
L. M. BINI ◽  
A. S. G COELHO ◽  
J. A. F. DINIZ-FILHO
Keyword(s):  
Body Size ◽  
Population Density ◽  
Regression Model ◽  
Phylogenetic Relationships ◽  
Analytical Approach ◽  
Analytical Procedure ◽  
Significant Heterogeneity ◽  
Sampling Variation ◽  
Homogeneity Hypothesis ◽  
The Relationship

The Energetic Equivalence Rule (EER) is a controversial issue in ecology. This rule states that the amount of energy that each species uses per unit of area is independent of its body size. Here, we perform a meta-analytical procedure to combine and compare the slopes of population density and body size relationships across independent studies of mammals and birds. We then compared a distribution of 50,000 bootstrap combined slopes with the expected slope (b = -0.75) under the EER. The combined slopes obtained for mammals and birds separately were -0.755 and -0.321, respectively. The homogeneity hypothesis (i. e. within studies the slopes differ by no more than would be expected due sampling variation) was rejected in both cases. So, EER cannot be supported since the use of an exponent of -0.75 is, in fact, an oversimplification. Significant heterogeneity of slopes within each group (mammals and birds) is an indicator of inferential problems related with variation in body size, spatial scale, the regression model adopted and phylogenetic relationships among species. So, we consider that questions regarding the estimation and validity of slopes is the next challenge of density-body size relationship studies.

The Relationship between Population Density and Body Size: The Role of Extinction and Mobility

Oikos ◽  
1995 ◽  
Vol 73 (2) ◽  
pp. 225 ◽  
Author(s):  
Bo Ebenman ◽  
Anders Hendenström ◽  
Uno Wennergren ◽  
Börje Ekstam ◽  
Jan Landin ◽  
...  
Keyword(s):  
Body Size ◽  
Population Density ◽  
The Relationship

Using The Fully Modified M Method In Estimating The Effect Of Cultivated Area On Barley Production In Iraq For The Period 1970-2018

2020 ◽  
Vol 2020 (66) ◽  
pp. 101-110
Author(s):  
. Azhar Kadhim Jbarah ◽  
Prof Dr. Ahmed Shaker Mohammed
Keyword(s):  
Regression Model ◽  
Moving Average ◽  
Estimation Method ◽  
Estimation Methods ◽  
Autoregressive Moving Average ◽  
Moving Average Models ◽  
Error Terms ◽  
Relationship Of ◽  
The Relationship ◽  
Barley Crop

The research is concerned with estimating the effect of the cultivated area of barley crop on the production of that crop by estimating the regression model representing the relationship of these two variables. The results of the tests indicated that the time series of the response variable values is stationary and the series of values of the explanatory variable were nonstationary and that they were integrated of order one ( I(1) ), these tests also indicate that the random error terms are auto correlated and can be modeled according to the mixed autoregressive-moving average models ARMA(p,q), for these results we cannot use the classical estimation method to estimate our regression model, therefore, a fully modified M method was adopted, which is a robust estimation methods, The estimated results indicate a positive significant relation between the production of barley crop and cultivated area.

The role of social norms in the relationship between anti-smoking advertising campaigns and smoking cessation: a scoping review

2020 ◽  
Vol 35 (3) ◽  
pp. 179-194
Author(s):  
Joanne Dono ◽  
Caroline Miller ◽  
Kerry Ettridge ◽  
Carlene Wilson
Keyword(s):  
Smoking Cessation ◽  
Social Norms ◽  
Scoping Review ◽  
Social Norm ◽  
Significant Heterogeneity ◽  
Mass Media Campaign ◽  
Media Campaign ◽  
Theoretical Understanding ◽  
The Relationship

Abstract A systematic scoping review of anti-smoking mass media campaign literature provided opportunity to explore how social normative theories and constructs are used to influence smoking cessation. Synthesis of findings was constrained by significant heterogeneity. Nevertheless, the results indicate that a broader conceptualization of social norm is worthy of further exploration. Perceptions of what others think and do contributed in multiple ways to the relationship between anti-smoking messaging and quitting outcomes. Furthermore, integrating research on social norms, social identity and communication may improve understanding of why quitting intentions are enhanced in some circumstances but reactance and counter-arguing responses corresponding to lower quitting intentions occur in others. Integrating a broader theoretical understanding of normative influences into campaign development and evaluation may prove useful in demonstrating the effectiveness of this approach in behaviour change campaigns.

Leg Strength Is Related to Endurance Run Performance in Children and Adolescents with Mental Retardation

2000 ◽  
Vol 12 (3) ◽  
pp. 324-333 ◽  
Author(s):  
Bo Fernhall ◽  
Kenneth H. Pitetti
Keyword(s):  
Mental Retardation ◽  
Body Size ◽  
Children And Adolescents ◽  
Aerobic Capacity ◽  
Significant Influence ◽  
Moderate Mental Retardation ◽  
Leg Strength ◽  
And Gender ◽  
The Relationship ◽  
Shuttle Run

This study evaluated the relationship between leg strength and endurance run performance, independent of aerobic capacity (V̇O2peak), body size, and gender, in children and adolescents with mild or moderate mental retardation. Twenty-six individuals (15 boys and 11 girls) volunteered and underwent tests of V̇O2peak, isokinetic leg strength, and endurance run performance (600-yard ran/walk and 20-m shuttle run). Results showed that leg strength was significantly related to both types of run performance; however, when controlling for V̇O2peak, body size, and gender, leg strength was a more significant contributor to the 600-yard run/walk than to 20-m shuttle run performance. Gender did not influence these relationships. These data suggest that leg strength has a significant influence on endurance run performance in children and adolescents with mild or moderate mental retardation.

scholarly journals Intraspecific Variation in Maximum Ingested Food Size and Body Mass in Varecia rubra and Propithecus coquereli

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Adam Hartstone-Rose ◽  
Jonathan M. G. Perry
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Individual Variation ◽  
Size Variation ◽  
Maximum Size ◽  
Least Squares Regression ◽  
Scaling Relationship ◽  
Varecia Rubra ◽  
Food Size ◽  
The Relationship

In a recent study, we quantified the scaling of ingested food size (Vb )—the maximum size at which an animal consistently ingests food whole—and found that Vb scaled isometrically between species of captive strepsirrhines. The current study examines the relationship between Vb and body size within species with a focus on the frugivorous Varecia rubra and the folivorous Propithecus coquereli. We found no overlap in Vb between the species (all V. rubra ingested larger pieces of food relative to those eaten by P. coquereli), and least-squares regression of Vb and three different measures of body mass showed no scaling relationship within each species. We believe that this lack of relationship results from the relatively narrow intraspecific body size variation and seemingly patternless individual variation in Vb within species and take this study as further evidence that general scaling questions are best examined interspecifically rather than intraspecifically.

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