Multiple Comparisons Using Rank Sums

Dunn, Olive Jean

doi:10.2307/1266041

Cited by 1,395 publications

(1,222 citation statements)

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“…Pairwise comparisons, using Dunn’s test for multiple comparisons with one control, were made with dunn.test.control function from the PMCMR package (adjusted p ‐value <0.05; Dunn, 1964). …”

Section: Methodsmentioning

confidence: 99%

Fitness costs of key point mutations that underlie acaricide target‐site resistance in the two‐spotted spider miteTetranychus urticae

Bajda

Riga

Wybouw

et al. 2018

Evolutionary Applications

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The frequency of insecticide/acaricide target‐site resistance is increasing in arthropod pest populations and is typically underpinned by single point mutations that affect the binding strength between the insecticide/acaricide and its target‐site. Theory predicts that although resistance mutations clearly have advantageous effects under the selection pressure of the insecticide/acaricide, they might convey negative pleiotropic effects on other aspects of fitness. If such fitness costs are in place, target‐site resistance is thus likely to disappear in the absence of insecticide/acaricide treatment, a process that would counteract the spread of resistance in agricultural crops. Hence, there is a great need to reliably quantify the various potential pleiotropic effects of target‐site resistance point mutations on arthropod fitness. Here, we used near‐isogenic lines of the spider mite pest Tetranychus urticae that carry well‐characterized acaricide target‐site resistance mutations to quantify potential fitness costs. Specifically, we analyzed P262T in the mitochondrial cytochrome b, the combined G314D and G326E substitutions in the glutamate‐gated chloride channels, L1024V in the voltage‐gated sodium channel, and I1017F in chitin synthase 1. Five fertility life table parameters and nine single‐generation life‐history traits were quantified and compared across a total of 15 mite lines. In addition, we monitored the temporal resistance level dynamics of populations with different starting frequency levels of the chitin synthase resistant allele to further support our findings. Three target‐site resistance mutations, I1017F and the co‐occurring G314D and G326E mutations, were shown to significantly and consistently alter certain fitness parameters in T. urticae. The other two mutations (P262T and L1024V) did not result in any consistent change in a fitness parameter analyzed in our study. Our findings are discussed in the context of the global spread of T. urticae pesticide resistance and integrated pest management.

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Section: Methodsmentioning

confidence: 99%

Fitness costs of key point mutations that underlie acaricide target‐site resistance in the two‐spotted spider miteTetranychus urticae

Bajda

Riga

Wybouw

et al. 2018

Evolutionary Applications

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show abstract

“…Nonetheless, a KruskalWallis H test was also conducted and showed that motivation to learn more programming was different for the three heteroskedastic groups χ 2 (2) = 68.58, p < .001. Pairwise analyses were performed using a Dunn rank sum test (Dunn 1964) with a Bonferroni adjustment. Results show that there was no significant difference in effects (z = .65, p = .77) between Me and Together, but there were significant differences in effects (z = 5.60, p < .001; z = 8.31, p < .001) between these two categories and Others.…”

Section: Motivationmentioning

confidence: 99%

Gender, interest, and prior experience shape opportunities to learn programming in robotics competitions

et al. 2016

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Background: Robotics competitions are increasingly popular and potentially provide an on-ramp to computer science, which is currently highly gender imbalanced. However, within competitive robotics teams, student participation in programming is not universal. This study gathered surveys from over 500 elementary, middle, and high school robotics competition participants to examine (1) whether programming involvement in these competitions is associated with motivation to pursue additional programming experiences and (2) whether opportunities to learn programming varied by gender, age, and competition type. Results: Results showed a significant association of students' programming involvement with their motivation to learn more programming. Interestingly, in the youngest groups/entry-level competitions, girls were heavily involved in programming. Unfortunately, in older/more advanced competitions, girls were generally less involved in programming, even after controlling for prior programming experience. These gendered effects were substantially explained by programming interest. Conclusions: While robotics competition experiences may motivate students to learn more programming, gender gaps in programming involvement persist in these learning environments and appear to widen as students grow older and enter more advanced competitions. Therefore, addressing gender imbalances in programming will likely require greater attention to particular curricular and pedagogical characteristics of robotics competitions that support girls' interest and involvement in programming.

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“…We used multivariate analysis techniques such as principal component analysis (PCA) and one-way pairwise analysis of similarity (ANOSIM; Hammer et al 2004) to identify distinct groups or patterns in grass species composition of our sample plots. We applied a Kruskal-Wallis test and a multiple comparison post-hoc test after Dunn (1964) for differences of the most common grass species growing inside and outside of the Roan enclosure beneath and outside canopies. …”

Section: Statistical Analysesmentioning

confidence: 99%

Tree size and herbivory determine below-canopy grass quality and species composition in savannahs

2009

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Large single-standing trees are rapidly declining in savannahs, ecosystems supporting a high diversity of large herbivorous mammals. Savannah trees are important as they support both a unique flora and fauna. The herbaceous layer in particular responds to the structural and functional properties of a tree. As shrubland expands stem thickening occurs and large trees are replaced by smaller trees. Here we examine whether small trees are as effective in providing advantages for grasses growing beneath their crowns as large trees are. The role of herbivory in this positive tree-grass interaction is also investigated. We assessed soil and grass nutrient content, structural properties, and herbaceous species composition beneath trees of three size classes and under two grazing regimes in a South African savannah. We found that grass leaf content (N and P) beneath the crowns of particularly large (ca. 3.5 m) and very large trees (ca. 9 m) was as much as 40% greater than the same grass species not growing under a tree canopy, whereas nutrient contents of grasses did not differ beneath small trees (\2.3 m). Moderate herbivory enhanced these effects slightly. Grass species composition differed beneath and beyond the tree canopy but not between tree size classes. As large trees significantly improve the grass nutrient quality for grazers in contrast to smaller trees, the decline of the former should be halted. The presence of trees further increases grass species diversity and patchiness by favouring shade-tolerant species. Both grazing wildlife and livestock will benefit from the presence of large trees because of their structural and functional importance for savannahs.

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Multiple Comparisons Using Rank Sums

Cited by 1,395 publications

References 0 publications

Fitness costs of key point mutations that underlie acaricide target‐site resistance in the two‐spotted spider miteTetranychus urticae

Fitness costs of key point mutations that underlie acaricide target‐site resistance in the two‐spotted spider miteTetranychus urticae

Gender, interest, and prior experience shape opportunities to learn programming in robotics competitions

Tree size and herbivory determine below-canopy grass quality and species composition in savannahs

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