Individual-tree diameter growth model for fir plantations based on multi-level linear mixed effects models across southeast China

2013 ◽  
Vol 18 (4) ◽  
pp. 305-315 ◽  
Author(s):  
Lifang Zhao ◽  
Chunming Li ◽  
Shouzheng Tang
Keyword(s):  
Growth Model ◽  
Mixed Effects ◽  
Mixed Effects Models ◽  
Diameter Growth ◽  
Individual Tree ◽  
Linear Mixed Effects Models ◽  
Southeast China ◽  
Linear Mixed Effects ◽  
Tree Diameter ◽  
Multi Level

Detecting trends in diameter growth of Norway spruce on long-term forest research plots using linear mixed-effects models

2014 ◽  
Vol 133 (5) ◽  
pp. 783-792 ◽  
Author(s):  
Chaofang Yue ◽  
Hans-Peter Kahle ◽  
Ulrich Kohnle ◽  
Qing Zhang ◽  
Xingang Kang
Keyword(s):  
Norway Spruce ◽  
Mixed Effects ◽  
Mixed Effects Models ◽  
Diameter Growth ◽  
Forest Research ◽  
Linear Mixed Effects Models ◽  
Linear Mixed Effects

A novel approach to selecting a competition index: the effect of competition on individual-tree diameter growth of Calabrian pine

2018 ◽  
Vol 48 (10) ◽  
pp. 1217-1226 ◽  
Author(s):  
Aydın Kahriman ◽  
Abdurrahman Şahin ◽  
Turan Sönmez ◽  
Mehmet Yavuz
Keyword(s):  
Mediterranean Region ◽  
Mixed Effects ◽  
Mixed Effects Models ◽  
Diameter Growth ◽  
Competition Index ◽  
Central Mediterranean ◽  
Individual Tree ◽  
Tree Diameter ◽  
Calabrian Pine ◽  
Competition Indices

In this study, we evaluated the performance of 18 competition indices composed of nine distance-dependent and nine distance-independent indices in explaining the variation in individual-tree diameter growth of Calabrian pine (Pinus brutia Ten.) in the central Mediterranean region of Turkey. The data were obtained from 432 sample plots with varying stand age, site index, and stand density. To evaluate the performance of each competition index, the mean square error reduction approach was used relative to the noncompetition. Also, this study compared fixed and mixed effects models to analyze diameter growth. Statistical analyses showed that the best distance-independent competition indices performed as well as the best distance-dependent competition indices. The distance-independent competition index of Schröder and Gadow (1999; Can. J. For. Res. 29(2): 280–283, doi: 10.1139/x98-199) performed best and is recommended for use in future growth and yield models to be used in the central Mediterranean region of Turkey. Also, the best selection of competitive neighbors was achieved using the area of influence overlap method, whereas the fixed-radius and angle count sampling methods had no significant improvement in quantifying the competition effects. On the other hand, all mixed effects models provided much better fits than their fixed model counterparts.

The Use of Theory of Linear Mixed-Effects Models to Detect Fraudulent Erasures at an Aggregate Level

2021 ◽  
pp. 001316442199489
Author(s):  
Luyao Peng ◽  
Sandip Sinharay
Keyword(s):  
Type I Error ◽  
Real Data ◽  
Mixed Effects ◽  
Error Rates ◽  
Mixed Effects Models ◽  
Type I ◽  
Aggregate Level ◽  
Linear Mixed Effects Models ◽  
Linear Mixed Effects ◽  
Best Linear Unbiased

Wollack et al. (2015) suggested the erasure detection index (EDI) for detecting fraudulent erasures for individual examinees. Wollack and Eckerly (2017) and Sinharay (2018) extended the index of Wollack et al. (2015) to suggest three EDIs for detecting fraudulent erasures at the aggregate or group level. This article follows up on the research of Wollack and Eckerly (2017) and Sinharay (2018) and suggests a new aggregate-level EDI by incorporating the empirical best linear unbiased predictor from the literature of linear mixed-effects models (e.g., McCulloch et al., 2008). A simulation study shows that the new EDI has larger power than the indices of Wollack and Eckerly (2017) and Sinharay (2018). In addition, the new index has satisfactory Type I error rates. A real data example is also included.

scholarly journals Association of body condition with lameness in dairy cattle: a single-farm longitudinal study

2021 ◽  
pp. 1-4
Author(s):  
Michaela Kranepuhl ◽  
Detlef May ◽  
Edna Hillmann ◽  
Lorenz Gygax
Keyword(s):  
Body Condition ◽  
Body Condition Score ◽  
Mixed Effects ◽  
Mixed Effects Models ◽  
Linear Mixed Effects Models ◽  
Linear Mixed Effects ◽  
Confounding Variables ◽  
Condition Score ◽  
The Impact ◽  
The Relationship

Abstract This research communication describes the relationship between the occurrence of lameness and body condition score (BCS) in a sample of 288 cows from a single farm that were repeatedly scored in the course of 9 months while controlling for confounding variables. The relationship between BCS and lameness was evaluated using generalised linear mixed-effects models. It was found that the proportion of lame cows was higher with decreasing but also with increasing BCS, increased with lactation number and decreased with time since the last claw trimming. This is likely to reflect the importance of sufficient body condition in the prevention of lameness but also raises the question of the impact of overcondition on lameness and the influence of claw trimming events on the assessment of lameness. A stronger focus on BCS might allow improved management of lameness that is still one of the major problems in housed cows.

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