scholarly journals On Bayesian $D$-optimal design criteria and the General Equivalence Theorem in joint generalized linear models for the mean and dispersion

2014 ◽  
Vol 28 (4) ◽  
pp. 483-491
Author(s):  
Edmilson Rodrigues Pinto ◽  
Antônio Ponce de Leon
Keyword(s):  
Optimal Design ◽  
Generalized Linear Models ◽  
Linear Models ◽  
Equivalence Theorem ◽  
Design Criteria ◽  
The Mean ◽  
General Equivalence Theorem

scholarly journals Association Between Pulsatile Components of Blood Pressure and Severe Tooth Loss in Rural Ecuador: The Three Villages Study

2020 ◽  
Vol 11 ◽  
pp. 215013272092867 ◽  
Author(s):  
Oscar H. Del Brutto ◽  
Robertino M. Mera ◽  
Bettsy Y. Recalde ◽  
Andrew P. Torpey ◽  
John P. Hill ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Hypertension ◽  
Generalized Linear Models ◽  
Tooth Loss ◽  
Linear Models ◽  
Community Dwelling ◽  
Multivariate Models ◽  
Mediation Analyses ◽  
The Mean ◽  
Relevant Covariates

Background: Arterial hypertension has been associated with severe tooth loss, but differential associations with individual components of blood pressure (BP) have scarcely been investigated. We assessed the independent associations between pulsatile/steady components of BP and severe tooth loss in community-dwelling adults residing in 3 rural Ecuadorian villages. Methods: Individuals aged ≥40 years living in Atahualpa, El Tambo, and Prosperidad were identified during door-to-door surveys. Data collection focused on the number of remaining teeth and measurements of pulsatile/steady components of BP. Multivariate models were fitted to assess independent associations between pulsatile/steady BP components and severe tooth loss, after adjusting for relevant covariates. Results: A total of 1543 individuals were included. Oral exams identified 426 (28%) individuals with severe tooth loss. BP levels ≥140/90 mm Hg were determined in 481 (31%) individuals. The mean pulse pressure (PP) level was 55.3 ± 19 mm Hg. For systolic BP (SBP), the mean level was 133.1 ± 23.5 mm Hg, and for diastolic BP (DBP) it was 77.8 ± 11.5 mm Hg. Univariate models showed significant associations between severe tooth loss and SBP and PP, but not with DBP. However, the significance was taken away in fully adjusted generalized linear models. Age remained as an independent significant covariate in models using SBP and PP. Causal mediation analyses disclosed that percentages of the effect of severe tooth loss mediated by age were 99.5% for SBP and 98.9% for PP. Conclusion: This study shows that age captures most of the effect of the association between pulsatile components of BP and severe tooth loss.

scholarly journals The opposite effects of routine metabolic rate and metabolic rate during startle responses on variation in the predictability of behaviour in hermit crabs

Behaviour ◽  
2016 ◽  
Vol 153 (13-14) ◽  
pp. 1545-1566 ◽  
Author(s):  
Mariana Velasque ◽  
Mark Briffa
Keyword(s):  
Metabolic Rate ◽  
Generalized Linear Models ◽  
Startle Response ◽  
Linear Models ◽  
Elevated Temperatures ◽  
Hermit Crabs ◽  
Routine Metabolic Rate ◽  
Intraindividual Variation ◽  
The Mean ◽  
Pagurus Bernhardus

Studies on animal behaviour have suggested a link between personality and energy expenditure. However, most models assume constant variation within individuals, even though individuals vary between observations. Such variation is called intraindividual variation in behaviour (IIV). We investigate if IIV in the duration of the startle response is associated with metabolic rates (MR) in the hermit crabPagurus bernhardus. We repeatedly measured startle response durations and MR during each observation. We used double hierarchical generalized linear models to ask whether among and IIV in behaviour was underpinned by MR. We found no association between the mean duration of the startle responses and either routine MR or MR during startle response. Nevertheless, we found that IIV increased with MR during startle responses and decreased with routine MR. These results indicate that crabs with higher MR during startle responses behave less predictably, and that predictability is reduced during exposure to elevated temperatures.

scholarly journals Movement distances for four small mammals in two Atlantic forests fragments, Southern Brazil

2021 ◽  
Vol 16 (1) ◽  
pp. 11-18
Author(s):  
Daniela Oliveira de Lima ◽  
Luana Gabriele Arenhart Braun ◽  
Fabrício Luiz Skupien ◽  
Daniele Pereira Rodrigues ◽  
Jady de Oliveira Sausen
Keyword(s):  
Body Weight ◽  
Generalized Linear Models ◽  
Linear Models ◽  
Animal Movement ◽  
Individual Performance ◽  
Southern Brazil ◽  
Climatic Effects ◽  
Independent Variables ◽  
The Mean ◽  
Didelphis Albiventris

Animal movement has an important role in individual performance, species reproduction, population demography, and conservation, especially in fragmented landscapes. The distance moved by an individual may vary depending on individual needs, such as the search for food resources and sexual partners. Here we investigated which factors affect the distances between successive captures (hereafter DSC) for Akodon montensis, Oligoryzomys nigripes, Sooretamys angouya, and Didelphis albiventris. This study was conducted from April 2015 to October 2016 in two fragments in the south of Atlantic Forest biome through capture, mark and recapture technique. DSC was analyzed using Generalized Linear Models with Poisson distribution where the independent variables were sex, whether the animal was active or not in terms of reproduction, body weight, and climatic season. The mean DSC was greater for D. albiventris (44.6 ± 28.8 m), followed by S. angouya (31.9 ± 25.7 m), O. nigripes (25.8 ± 22.5 m) and A. montensis (18.9 ± 22.0 m). Males of all species moved larger DSC than females. Considering the rodents, reproductive animals also moved larger DSC than non-reproductive animals. Sex may have masked the effect of body weight, as males tend to be larger than females. Climatic effects were tested for A. montensis and O. nigripes, however, with diverse effects.

Generalized Linear Models

2021 ◽  
pp. 195-208
Author(s):  
Andy Hector
Keyword(s):  
Regression Analysis ◽  
Maximum Likelihood ◽  
Generalized Linear Models ◽  
Linear Models ◽  
Square Root ◽  
Link Function ◽  
Data Transformations ◽  
Normal Distributions ◽  
Equal Variance ◽  
The Mean

This chapter revisits a regression analysis to explore the normal least squares assumption of approximately equal variance. It also considers some of the data transformations that can be used to achieve this. A linear regression of transformed data is compared with a generalized linear-model equivalent that avoids transformation by using a link function and non-normal distributions. Generalized linear models based on maximum likelihood use a link function to model the mean (in this case a square-root link) and a variance function to model the variability (in this case the gamma distribution, where the variance increases as the square of the mean). The Box–Cox family of transformations is explained in detail.

scholarly journals R-optimal designs for second-order Scheffé model with qualitative factors

2021 ◽  
Vol 7 (3) ◽  
pp. 4540-4551
Author(s):  
Ling Ling ◽  
◽  
Guanghui Li ◽  
Xiaoyuan Zhu ◽  
Chongqi Zhang ◽  
...  
Keyword(s):  
Optimal Design ◽  
Relative Efficiency ◽  
Design Problem ◽  
Equivalence Theorem ◽  
Decision Function ◽  
Optimal Designs ◽  
Optimal Design Problem ◽  
Qualitative Factors ◽  
General Equivalence Theorem ◽  
Analytical Expressions

<abstract><p>Considering a mixture model with qualitative factors, the $ R $-optimal design problem is investigated when the levels of the qualitative factor interact with the mixture factors. In this paper, the conditions for $ R $-optimality of designs with mixture and qualitative factors are presented. General analytical expressions are also derived for the decision function under the $ R $-optimal designs, in order to verify that the resulting designs satisfy the general equivalence theorem. In addition, the relative efficiency of the $ R $-optimal design is discussed.</p></abstract>

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