Antisymmetry, directional asymmetry, and dynamic morphogenesis

1994 ◽  
pp. 123-139 ◽  
Author(s):  
John H. Graham ◽  
D. Carl Freeman ◽  
John M. Emlen
Keyword(s):  
Directional Asymmetry

scholarly journals Investigating the reliability and sex differences of digit lengths, ratios, and hand measures in infants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Luisa Ernsten ◽  
Lisa M. Körner ◽  
Martin Heil ◽  
Gareth Richards ◽  
Nora K. Schaal
Keyword(s):  
Sex Differences ◽  
Measurement Techniques ◽  
Directional Asymmetry ◽  
Computer Assisted ◽  
Sexually Dimorphic ◽  
Digit Ratios ◽  
Androgen Exposure ◽  
Prenatal Androgen Exposure ◽  
Test Retest Reliability ◽  
Prenatal Androgen

AbstractHands and digits tend to be sexually dimorphic and may reflect prenatal androgen exposure. In the past years, the literature introduced several hand and digit measures, but there is a lack of studies in prepubertal cohorts. The available literature reports more heterogeneous findings in prepubertal compared to postpubertal cohorts. The comparability of the available studies is further limited by the study design and different measurement techniques. The present study compared the reliability and sex differences of available hand and digit measures, namely digit lengths of 2D, 3D, 4D, 5D, digit ratios 2D:4D, 2D:5D, 3D:4D, 3D:5D, 4D:5D, relative digit lengths rel2, rel3, rel4, rel5, directional asymmetry of right and left 2D:4D (Dr-l), hand width, length, and index of 399 male and 364 female 6-month-old German infants within one study using only indirect and computer-assisted measurements. The inter-examiner reliability was excellent while the test-retest reliability of hand scans was only moderate to high. Boys exhibited longer digits as well as wider and longer hands than girls, but smaller digit ratios, with ratios comprising the fifth digit revealing the largest effect sizes. Other hand and digit ratios revealed sex differences to some extent. The findings promote the assumption of sexual dimorphic hand and digit measures. However, by comparing the results of the available literature, there remains an uncertainty regarding the underlying hypothesis. Specifically in prepubertal cohorts, i.e. before the influence of fluctuating hormones, significant effects should be expected. It seems like other factors than the influence of prenatal androgens contribute to the sexual dimorphism in hand and digit lengths.

The Asymmetry of Space: Kant’s Theory of Absolute Space in 1768

2016 ◽  
Vol 21 (3) ◽  
pp. 415-435 ◽  
Author(s):  
Matthew S. Rukgaber
Keyword(s):  
Directional Asymmetry ◽  
Absolute Space ◽  
Dynamic Features ◽  
Critical Thought ◽  
The Asymmetry ◽  
Incongruent Counterparts ◽  
Ultimate Ground

AbstractI propose that we interpret Kant’s argument from incongruent counterparts in the 1768 article ‘Concerning the Ultimate Ground of the Differentiation of Directions in Space’ in light of a theory of dynamic absolute space that he accepted throughout the 1750s and 1760s. This force-based or material conception of space was not an unusual interpretation of the Newtonian notion of absolute space. Nevertheless, commentators have continually argued that Kant’s argument is an utter failure that shifts from the metaphysics of space to its epistemology, because he has no way to connect ‘directionality’ and ‘handedness’ to absolute space. This supposed failure is based on an understanding of absolute space in purely mathematical terms and as an absolute void that lacks any qualitative or dynamic features. If we recognize that Kant held that space had an intrinsic directional asymmetry then his argument successfully connects incongruent counterparts to absolute space. The presence of this notion in Kant’s pre-Critical thought is rarely noted, and its necessity in understanding his incongruence argument is novel.

What Goes Up Might Not Come Down: Modeling Directional Asymmetry with Large-N, Large-T Data

2021 ◽  
pp. 008117502110463
Author(s):  
Ryan P. Thombs ◽  
Xiaorui Huang ◽  
Jared Berry Fitzgerald
Keyword(s):  
Fixed Effects ◽  
Directional Asymmetry ◽  
Cross Sectional ◽  
Monte Carlo Experiments ◽  
Long Run ◽  
Large N ◽  
Fixed Effects Estimator ◽  
Cross Sectional Dependence ◽  
Using Data ◽  
Heterogeneous Panel

Modeling asymmetric relationships is an emerging subject of interest among sociologists. York and Light advanced a method to estimate asymmetric models with panel data, which was further developed by Allison. However, little attention has been given to the large- N, large- T case, wherein autoregression, slope heterogeneity, and cross-sectional dependence are important issues to consider. The authors fill this gap by conducting Monte Carlo experiments comparing the bias and power of the fixed-effects estimator to a set of heterogeneous panel estimators. The authors find that dynamic misspecification can produce substantial biases in the coefficients. Furthermore, even when the dynamics are correctly specified, the fixed-effects estimator will produce inconsistent and unstable estimates of the long-run effects in the presence of slope heterogeneity. The authors demonstrate these findings by testing for directional asymmetry in the economic development–CO2 emissions relationship, a key question in macro sociology, using data for 66 countries from 1971 to 2015. The authors conclude with a set of methodological recommendations on modeling directional asymmetry.

scholarly journals Towards More Realistic Leaf Shapes in Functional-Structural Plant Models

Symmetry ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 278 ◽  
Author(s):  
Dominik Schmidt ◽  
Katrin Kahlen
Keyword(s):  
Fluctuating Asymmetry ◽  
Leaf Shape ◽  
Three Dimensional ◽  
Directional Asymmetry ◽  
The Novel ◽  
Shape Model ◽  
Plant Model ◽  
Virtual Plant ◽  
Perfect Symmetry

Fluctuating asymmetry in plant leaves is a widely used measure in geometric morphometrics for assessing random deviations from perfect symmetry. In this study, we considered the concept of fluctuating asymmetry to improve the prototype leaf shape of the functional-structural plant model L-Cucumber. The overall objective was to provide a realistic geometric representation of the leaves for the light sensitive plant reactions in the virtual plant model. Based on three-dimensional data from several hundred in situ digitized cucumber leaves comparisons of model leaves and measurements were conducted. Robust Bayesian comparison of groups was used to assess statistical differences between leaf halves while respecting fluctuating asymmetries. Results indicated almost no directional asymmetry in leaves comparing different distances from the prototype while detecting systematic deviations shared by both halves. This information was successfully included in an improved leaf prototype and implemented in the virtual plant model L-Cucumber. Comparative virtual plant simulations revealed a slight improvement in plant internode development against experimental data using the novel leaf shape. Further studies can now focus on analyses of stress on the 3D-deformation of the leaf and the development of a dynamic leaf shape model.

scholarly journals Testosterone measured from amniotic fluid and maternal plasma shows no significant association with directional asymmetry in newborn digit ratio (2D:4D)

2018 ◽  
Vol 10 (3) ◽  
pp. 362-367 ◽  
Author(s):  
G. Richards ◽  
M. Gomes ◽  
T. Ventura
Keyword(s):  
Amniotic Fluid ◽  
Secondary Analysis ◽  
Relative Length ◽  
Maternal Plasma ◽  
Mean Value ◽  
Digit Ratio ◽  
Directional Asymmetry ◽  
Second Trimester ◽  
Maternal Circulation ◽  
Left Hand

AbstractFoetal sex hormones can have powerful and far-reaching effects on later phenotype. However, obtaining accurate measurements is difficult for ethical reasons, and researchers often employ proxy variables to examine their effects. The relative length of the second and fourth fingers (digit ratio or 2D:4D) is frequently used for this purpose, as it is hypothesized to index variance in prenatal androgen and oestrogen exposure. Most studies employing this method examine digit ratio for the right hand (R2D:4D) and/or left hand (L2D:4D), though the mean value (M2D:4D) (i.e., the average of R2D:4D and L2D:4D) and directional asymmetry (D[R–L]) (i.e., R2D:4D minus L2D:4D) are also commonly used. As no published studies have examined M2D:4D or D[R-L] in relation to testosterone measured from amniotic fluid, we conducted a secondary analysis of data published by Ventura et al. The sample comprises 106 mothers from Portugal who underwent amniocentesis during the second trimester and their neonates. Newborn M2D:4D was negatively correlated with amniotic testosterone in females (P<0.05) but not in males; no significant association was observed between amniotic testosterone and D[R–L] in either sex. In addition, we examined testosterone measured from maternal circulation during the second trimester, and found that it was not a significant predictor of M2D:4D or D[R–L] in male or female infants. Further research should aim to measure the ratio of testosterone to oestradiol present in amniotic fluid and maternal plasma, to examine whether either is a predictor of digit ratio variables at different stages of postnatal development.

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