Fluctuating asymmetry in an ornamental trait in the cave weta, Pleioplectron simplex Hutton (Orthoptera: Rhaphidophoridae): no role for parasites

1998 ◽  
Vol 76 (5) ◽  
pp. 931-935 ◽  
Author(s):  
F Thomas ◽  
D F Ward ◽  
R Poulin
Keyword(s):  
Measurement Error ◽  
Fluctuating Asymmetry ◽  
Expression Intensity ◽  
Stabilising Selection ◽  
Significant Difference ◽  
Cuticular Ornamentation

Using digitised pictures of the pronotum, we investigated the influence of nematomorph and mermithid parasites on the expression (intensity and fluctuating asymmetry) of cuticular ornamentation in the cave weta, Pleioplectron simplex. Because P. simplex is nocturnal, this ornamentation is probably not subject to strong directional or stabilising selection. Based on measurements of brightness, we found no significant difference in the amount of pigmented area between unparasitised and parasitised males or females. Parasitised individuals were not significantly more asymmetrical than unparasitised ones. This result was not due to measurement error. Among parasitised wetas, brightness and the fluctuating asymmetry were not related to the length of the parasite, even when the size of the host was taken into account. These results are discussed in relation to current ideas concerning the influence of parasites on fluctuating asymmetry of traits in the host.

scholarly journals Fluctuating Asymmetry and Developmental Instability, a Guide to Best Practice

Symmetry ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 9
Author(s):  
John H. Graham
Keyword(s):  
Measurement Error ◽  
Best Practices ◽  
Environmental Stress ◽  
Fluctuating Asymmetry ◽  
Best Practice ◽  
Developmental Instability ◽  
The Past ◽  
Size Scaling ◽  
Research Designs

Best practices in studies of developmental instability, as measured by fluctuating asymmetry, have developed over the past 60 years. Unfortunately, they are haphazardly applied in many of the papers submitted for review. Most often, research designs suffer from lack of randomization, inadequate replication, poor attention to size scaling, lack of attention to measurement error, and unrecognized mixtures of additive and multiplicative errors. Here, I summarize a set of best practices, especially in studies that examine the effects of environmental stress on fluctuating asymmetry.

Fluctuating Asymmetry and Measurement Error

1995 ◽  
Vol 44 (1) ◽  
pp. 97-101 ◽  
Author(s):  
Juha Merilä ◽  
Mats Björklund
Keyword(s):  
Measurement Error ◽  
Fluctuating Asymmetry

scholarly journals Quantification of Epicardial Fat using 3D Cine Dixon MRI

2020 ◽  
Author(s):  
Markus Henningsson ◽  
Martin Brundin ◽  
Tobias Scheffel ◽  
Carl Edin ◽  
Federica Viola ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Measurement Error ◽  
Single Phase ◽  
Image Quality Assessment ◽  
Epicardial Adipose Tissue ◽  
Interquartile Range ◽  
Epicardial Fat ◽  
Observer Variability ◽  
Inter Observer Variability ◽  
Significant Difference

Abstract Background There is an increased interest in quantifying and characterizing epicardial fat which has been linked to various cardiovascular diseases such as coronary artery disease and atrial fibrillation. Recently, three-dimensional single-phase Dixon techniques has been used to depict the heart and to quantify the surrounding fat. The purpose of this study was to investigate the merits of a new high-resolution cine 3D Dixon technique for quantification of epicardial adipose tissue and compare it to single-phase 3D Dixon in patients with cardiovascular disease.Methods Fifteen patients referred for clinical CMR examination of known or suspected heart disease were scanned on a 1.5T scanner using single-phase Dixon and cine Dixon. Epicardial fat was segmented by three readers and intra- and inter-observer variability was calculated per slice. Cine Dixon segmentation was performed in the same cardiac phase as single-phase Dixon. Subjective image quality assessment of water and fat images were performed by three readers using a 4-point Likert scale (1 = severe; 2 = significant; 3 = mild; 4 = no blurring of cardiac structures).Results Intra-observer variability was excellent for cine Dixon images (ICC = 0.96), and higher than single-phase Dixon (ICC = 0.92). Inter-observer variability was good for cine Dixon (ICC = 0.76) and moderate for single-phase Dixon (ICC = 0.63). The intra-observer measurement error (mean ± standard deviation) per slice for cine was − 0.02 ± 0.51 ml (-0.08 ± 0.4%), and for single-phase 0.39 ± 0.72 ml (0.18 ± 0.41%). Inter-observer measurement error for cine was 0.46 ± 0.98 ml (0.11 ± 0.46%) and for single-phase 0.42 ± 1.53 ml (0.17 ± 0.47%). Visual scoring of the water image yielded median of 2 (interquartile range = [Q3-Q1] 2–2) for cine and median of 3 (interquartile range = 3 − 2) for single-phase (P < 0.05) while no significant difference was found for the fat images, both techniques yielding a median of 3 and interquartile range of 3 − 2.Conclusion Cine Dixon can be used to quantify epicardial fat with lower intra- and inter-observer variability compared to standard single-phase Dixon. The time-resolved information provided by the cine acquisition appears to support the delineation of the epicardial adipose tissue depot.

scholarly journals A Detailed Analysis Of Clinical Measurement Error In Ultrafiltration In Peritoneal Dialysis

2021 ◽  
Author(s):  
Zanzhe Yu ◽  
Zhuqing Wang ◽  
Qin Wang ◽  
Minfang Zhang ◽  
Haijiao Jin ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Measurement Error ◽  
Specific Gravity ◽  
Pure Water ◽  
The Other ◽  
Cross Sectional ◽  
Clinical Measurement ◽  
Significant Difference ◽  
Higher Temperature ◽  
The Difference

Abstract BackgroundIt has been noticed for years that ultrafiltration is important for survival in peritoneal dialysis. On the other hand, ultrafiltration measurement is much more complicated than it thought to be. Both overfill and flush before fill used to be source of measurement error. However, controversy finding around ultrafiltration in peritoneal dialysis still exists.MethodsFour different brands of dialysate were purchased from the market. The freshest dialysate available in the market were intentionally picked. The dialysate were all 2L, 2.5% dextrose and traditional lactate buffered PD solution. They were stored in four different conditions with controlled temperature and humidity. The bags were weight at baseline, 6 months and 12 months of storage. Specific gravity was measured in mixed 24 hour drainage dialysate from 261 CAPD patients in a cross sectional manner. ResultsThere was significant difference in dialysate bag weight at baseline between brands. The weight declined significantly after 12 months storage. The weight loss was more significant in higher temperature and lower humidity. The dialysate in non-PVC package lose less weight than PVC package. The specific gravity of dialysate drainage was significantly higher than pure water and related to dialysate protein concentration.ConclusionStorage condition and duration, as well as the type of the dialysate package gave extra variance in overfill volume. The fact that specific gravity of dialysate drainage is higher than 1g/ml also contributes to systemic measurement error of ultrafiltration in manual exchanges.Trial Registration: ClinicalTrials.gov ID: NCT03864120 (March 8, 2019) (Understand the Difference Between Clinical Measured Ultrafiltration and Real Ultrafiltration)

scholarly journals Quantification of epicardial fat using 3D cine Dixon MRI

2020 ◽  
Author(s):  
Markus Henningsson ◽  
Martin Brundin ◽  
Tobias Scheffel ◽  
Carl Edin ◽  
Federica Viola ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Measurement Error ◽  
Single Phase ◽  
Image Quality Assessment ◽  
Epicardial Adipose Tissue ◽  
Interquartile Range ◽  
Epicardial Fat ◽  
Observer Variability ◽  
Inter Observer Variability ◽  
Significant Difference

Abstract Background: There is an increased interest in quantifying and characterizing epicardial fat which has been linked to various cardiovascular diseases such as coronary artery disease and atrial fibrillation. Recently, three-dimensional single-phase Dixon techniques have been used to depict the heart and to quantify the surrounding fat. The purpose of this study was to investigate the merits of a new high-resolution cine 3D Dixon technique for quantification of epicardial adipose tissue and compare it to single-phase 3D Dixon in patients with cardiovascular disease. Methods: Fifteen patients referred for clinical CMR examination of known or suspected heart disease were scanned on a 1.5T scanner using single-phase Dixon and cine Dixon. Epicardial fat was segmented by three readers and intra- and inter-observer variability was calculated per slice. Cine Dixon segmentation was performed in the same cardiac phase as single-phase Dixon. Subjective image quality assessment of water and fat images were performed by three readers using a 4-point Likert scale (1=severe; 2=significant; 3=mild; 4=no blurring of cardiac structures).Results: Intra-observer variability was excellent for cine Dixon images (ICC=0.96), and higher than single-phase Dixon (ICC=0.92). Inter-observer variability was good for cine Dixon (ICC=0.76) and moderate for single-phase Dixon (ICC=0.63). The intra-observer measurement error (mean ± standard deviation) per slice for cine was -0.02±0.51 ml (-0.08±0.4%), and for single-phase 0.39±0.72 ml (0.18±0.41%). Inter-observer measurement error for cine was 0.46±0.98 ml (0.11±0.46%) and for single-phase 0.42±1.53 ml (0.17±0.47%). Visual scoring of the water image yielded median of 2 (interquartile range = [Q3-Q1] 2-2) for cine and median of 3 (interquartile range = 3-2) for single-phase (P < 0.05) while no significant difference was found for the fat images, both techniques yielding a median of 3 and interquartile range of 3-2. Conclusion: Cine Dixon can be used to quantify epicardial fat with lower intra- and inter-observer variability compared to standard single-phase Dixon. The time-resolved information provided by the cine acquisition appears to support the delineation of the epicardial adipose tissue depot.

scholarly journals Asimetría cráneo-mandibular de Artibeus lituratus (Chiroptera, Phyllostomidae) en Colombia

2014 ◽  
Vol 20 (1) ◽  
pp. 141 ◽  
Author(s):  
Camilo López-Aguirre ◽  
Jairo Pérez-Torres
Keyword(s):  
Measurement Error ◽  
Fluctuating Asymmetry ◽  
Morphological Plasticity ◽  
Wide Distribution ◽  
Functional Similarity ◽  
High Abundance ◽  
Directional Asymmetry ◽  
Functional Importance ◽  
Mandibular Asymmetry ◽  
Artibeus Lituratus

Analyzing asymmetry in species associated with disturbed environments enables the evaluation of the morphological plasticity of generalistic species and the different evolutionary responses of sexes or populations to environmental or genetic stress. This report is a study of the cranial and mandibular asymmetry of Colombian Artibeus lituratus. This species has a wide distribution and high abundance, but its morphological plasticity remains uncertain. We characterized its presence, fluctuating asymmetry, directional asymmetry and antisymmetry by measuring 11 craneometric traits in 146 adults from different localities. Fluctuating asymmetry was present in all traits; directional asymmetry and antisymmetry in three; and no measurement error in any trait. Females showed more fluctuating asymmetry in the splachnocranium and males in the neurocranium. Traits with functional importance while biting had lower levels of asymmetry and higher similarity. Traits with antisymmetry did not show association while traits with directional asymmetry showed mandibular association. We discuss the relation between the presence of cranial and mandibular asymmetry, with the functional similarity of different traits.

Directional and fluctuating asymmetry in the black-winged damselfly Calopteryx maculata (Beauvois) (Odonata: Calopterygidae)

2000 ◽  
Vol 78 (10) ◽  
pp. 1740-1748 ◽  
Author(s):  
Jason Pither ◽  
Philip D Taylor
Keyword(s):  
Measurement Error ◽  
Fluctuating Asymmetry ◽  
Directional Asymmetry ◽  
Sample Group ◽  
Literature Evidence ◽  
Calopteryx Maculata

Directional asymmetry (DA) has received considerably less attention than fluctuating asymmetry (FA) in the literature. Evidence for DA, however, is building among insect taxa. We examined asymmetries in two wing traits within both sexes of the damselfly Calopteryx maculata (Beauvois) (Odonata: Calopterygidae) sampled from three sites in southeastern Ontario. After accounting for measurement error, we show that proximal segments within right fore and hind wings are consistently longer than those in the left in all but one sample group. Full wing lengths, however, exhibited FA rather than DA. Mean asymmetry values for both traits (segment and length) occurred in the direction of right-wingedness significantly more often than expected by chance. Patterns of asymmetry were generally consistent among the sexes and sites, although males tended to exhibit more pronounced DA. We suggest that the wings of C. maculata may undergo compensatory development, so that full lengths are more bilaterally symmetrical than their component parts.

scholarly journals Understand the difference between clinical measured ultrafiltrationand real ultrafiltration in peritoneal dialysis

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Zanzhe Yu ◽  
Zhuqing Wang ◽  
Qin Wang ◽  
Minfang Zhang ◽  
Haijiao Jin ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Measurement Error ◽  
Specific Gravity ◽  
Pure Water ◽  
Daily Practice ◽  
Storage Condition ◽  
Significant Difference ◽  
Higher Temperature ◽  
The Difference ◽  
Solute Clearance

Abstract Background It has been noticed for years that ultrafiltration (UF) is important for survival in peritoneal dialysis. On the other hand, precise and convenient UF measurement suitable for patient daily practice is not as straight forward as it is to measure UF in the lab. Both overfill and flush before fill used to be source of measurement error for clinical practice. However, controversy finding around UF in peritoneal dialysis still exists in some situation. The current study was to understand the difference between clinical measured UF and real UF. The effect of evaporation and specific gravity in clinical UF measurement were tested in the study. Methods Four different brands of dialysate were purchased from the market. The freshest dialysate available in the market were intentionally picked. The bags were all 2 L, 2.5% dextrose and traditional lactate buffered PD solution. They were stored in four different conditions with controlled temperature and humidity. The bags were weighted at baseline, 6 months and 12 months of storage. Specific gravity was measured in mixed 24 h drainage dialysate from 261 CAPD patients when they come for their routine solute clearance test. Results There was significant difference in dialysate bag weight at baseline between brands. The weight declined significantly after 12 month’s storage. The weight loss was greater in higher temperature and lower humidity. The dialysate in non-PVC package lose less weight than PVC package. The specific gravity of dialysate drainage was significantly higher than pure water and it was related to dialysate protein concentration. Conclusion Storage condition and duration, as well as the type of dialysate package have significant impact in dialysate bag weight before use. Evaporation is likely to be the reason behind. The fact that specific gravity of dialysate drainage is higher than 1 g/ml overestimates UF in manual exchanges, which contributes to systemic measurement error of ultrafiltration in CAPD. Trial registration ClinicalTrials.gov ID: NCT03864120 (March 8, 2019) (Understand the Difference Between Clinical Measured Ultrafiltration and Real Ultrafiltration).

scholarly journals Chiropteran Composition and Morphometric Analysis of Ptenochirus Jagori in Caraga State University, Caraga Region, Philippines

2021 ◽  
Vol 26 (1) ◽  
pp. 49-62
Author(s):  
Glenn Vallespin ◽  
Renalyn Torralba ◽  
Daniljun Sanchez ◽  
Jashin Rosal ◽  
Chennie Solania
Keyword(s):  
Morphometric Analysis ◽  
Fluctuating Asymmetry ◽  
Food Source ◽  
Shape Deformation ◽  
State University ◽  
Variation Analysis ◽  
Source Areas ◽  
Fruit Bat ◽  
Significant Difference ◽  
Canonical Variation

Due to potential and present ecological alteration in roosting sites and food source areas in neighboring vicinity of Caraga State University in Caraga Region, Philippines, unsettled progression of bats are documented through wing variation analysis and fluctuating asymmetry (FA). Twenty-one (21) collected samples of Ptenochirus jagori (Greater Musky Fruit Bat) yields asymmetry of 90.6396%, affecting landmarks of the elbow (landmark 1), carpals (landmark 2), metacarpals (landmark 3, 4, and 10), and phalanges’ fingers (landmarks 5, 6, 11, and 12). Wing variation (landmark-based) analysis suggested significant skewness on both elbows and metacarpals of wings. Wider shape deformation is on the rightwing, and a narrower one was analyzed on the left. Nonetheless, even though similar alteration is present between both wings, Canonical Variation Analysis (CVA) suggests no significant difference in the deformations of histogram analysis.

VMO:VL Ratios and Torque Comparisons at Four Angles of Knee Flexion

1995 ◽  
Vol 4 (4) ◽  
pp. 264-272 ◽  
Author(s):  
Teddy W. Worrell ◽  
Steven Connelly ◽  
John Hilvert
Keyword(s):  
Measurement Error ◽  
Future Study ◽  
Isometric Contraction ◽  
Knee Flexion ◽  
Vastus Medialis ◽  
Maximal Voluntary Isometric Contraction ◽  
Knee Position ◽  
Significant Difference ◽  
Intraclass Correlations ◽  
Asymptomatic Subjects

The purpose of this study was to determine the intrasession and intersessionreliabilityof EMG vastus medialis oblique:vastus lateralis (VMO:VL) ratios at four knee positions (0, 45, 60, and 90°) at 100 and 60% of maximal voluntary isometric contraction (MVIC). Once reliability was established, the second purpose was to determine VMO:VL ratios and torque at each knee position. Thirty-two subjects participated in two sessions; 19 subjects were tested at 100% MVIC and 13 were tested at .60% MVIC. Results revealed the following intraclass correlations: 100% MVIC intrasession .40-.80, intersession .40-.70; 60% MVIC intrasession .60-.90, intersession .50-.80. A significant difference in torque occurred at all knee positions except 60 versus 90°. No significant difference existed in VMO:VL ratios at the four positions of knee flexion. Pain and measurement error significantly increased during 100% MVIC testing. It was concluded that no selective VMO recruitment occurred as revealed by the VMO: VL ratios in asymptomatic subjects. Future study is needed that reports EMG reliability data during exercises that theorize selective VMO recruitment.

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