The relationship between sexual dimorphism in human faces and fluctuating asymmetry

Previous studies have found both support and lack of support for a positive relationship between masculinity and symmetry, two putative signs of mate quality, in male faces. We re-examined this relationship using an explicit measure of facial fluctuating asymmetry, as well as other measures of asymmetry, and measures of facial masculinity/femininity. We also used ratings of these traits for faces. Further, we examined the relationship between facial sexual dimorphism and body asymmetry. We found no significant correlations between facial masculinity and any of our measures of asymmetry or ratings of symmetry in males. Facial femininity was not consistently associated with facial symmetry in females, but was associated with body symmetry. Therefore, for females, but not males, facial femininity and body symmetry may reflect similar aspects of mate quality. We also examined the relationships between trait ratings and measurements. Our results provide validation of our ability to measure aspects of asymmetry that are perceived to be symmetrical, and aspects of sexual dimorphism that are perceived as feminine in females and masculine in males.

TMS stimulus-response asymmetry in left- and right handed individuals

There have been inconsistencies in the literature regarding asymmetrical neural control and results of experiments using TMS techniques. Therefore, the aim of this study was to further our understanding of the neural relationships that may underlie performance asymmetry with respect to the distal muscles of the hand using a TMS stimulus–response curve technique. Twenty-four male subjects (12 right handed, 12 left handed) participated in a TMS stimulus–response (S–R) curve trial. Focal TMS was applied over the motor cortex to find the optimal position for the first dorsal interossei muscle and to determine rest threshold (RTh). Seven TMS intensities ranging from 90 to 150 % of RTh were delivered in 10 % increments. One single TMS block consisted of 16 stimuli at each intensity. Peak-to-peak amplitudes were measured and the S–R curve generated. In right-handed subjects, the mean difference in slopes between the right and left hand was −0.011 ± 0.03, while the mean difference between hands in left-handed subjects was −0.049 ± 0.08. Left-handed normalized data in right handers displayed a mean of 1.616 ± 1.019 (two-tailed t test p < 0.05). The left-handed group showed a significant change in the normalized slope as indicated by a mean of 1.693 ± 0.149 (two-tailed t test p < 0.00006). The results found in this study reinforce previous work which suggests that there is an asymmetry in neural drive that exists in both left- and right-handed individuals. However, the results show that the non-dominant motor hemisphere displays a greater amount of excitability than the dominant, which goes against the conventional dogma. This asymmetry indicates that the non-dominant hemisphere may have a higher level of excitation or a lower level of inhibition for both groups of participants.

Phase inversion of ionomer-stabilized emulsions to form high internal phase emulsions (HIPEs)

Herein, we report the phase inversion of ionomer-stabilized emulsions to form high internal phase emulsions (HIPEs) induced by salt concentration and pH changes. The ionomers are sulfonated polystyrenes (SPSs) with different sulfonation degrees. The emulsion types were determined by conductivity measurements, confocal microscopy and optical microscopy, and the formation of HIPE organogels was verified by the tube-inversion method and rheological measurements. SPSs with high sulfonation degrees (water-soluble) and low sulfonation degrees (water-insoluble) can stabilize oil-in-water emulsions; these emulsions were transformed into water-in-oil HIPEs by varying salt concentrations and/or changing the pH. SPS, with a sulfonation degree of 11.6%, is the most efficient, and as low as 0.2 (w/v)% of the organic phase is enough to stabilize the HIPEs. Phase inversion of the oil-in-water emulsions occurred to form water-in-oil HIPEs by increasing the salt concentration in the aqueous phase. Two phase inversion points from oil-in-water emulsions to water-in-oil HIPEs were observed at pH 1 and 13. Moreover, synergetic effects between the salt concentration and pH changes occurred upon the inversion of the emulsion type. The organic phase can be a variety of organic solvents, including toluene, xylene, chloroform, dichloroethane, dichloromethane and anisole, as well as monomers such as styrene, butyl acrylate, methyl methacrylate and ethylene glycol dimethacrylate. Poly(HIPEs) were successfully prepared by the polymerization of monomers as the continuous phase in the ionomer-stabilized HIPEs.

Analysis of fetal heart rate asymmetry before and after 35 weeks of gestation

In this study, we have investigated the evidence of fetal heart rate asymmetry and how the fetal heart rate asymmetry changes before and after 35 weeks of gestation. Noninvasive fetal electrocardiogram (fECG) signals from 45 pregnant women at the gestational age from16 to 41 weeks with normal single pregnancies were analysed. A nonlinear parameter called heart rate asymmetry (HRA) index that measures time asymmetry of RR interval time-series signal was used to understand the changes of HRA in early and late fetus groups. Results indicate that fetal HRA measured by Porta's Index (PI) consistently increases after 35 weeks gestation compared to foetus before 32 weeks of gestation. It might be due to significant changes of sympatho-vagal balance towards delivery with more sympathetic surge. On the other hand, Guzik's Index (GI) showed a mixed effect i.e., increases at lower lags and decreases at higher lags. Finally, fHRA could potentially help identify normal and the pathological autonomic nervous system development.

Enhanced ductility and reduced asymmetry of Mg-2Al-1Zn alloy plate processed by torsion and annealing

The ductility and plastic asymmetry of an as-annealed magnesium alloy plate were studied in compression through combined process of torsion and subsequent annealing by optical microscope and EBSD. The yield strength (YS) and ultimate compression strength (UCS) as well as the compression ductility (CD) were simultaneously raised by prior torsion at room temperature. The CD was further enhanced by subsequent annealing. Also, the torqued sample followed by annealing experienced a rising CD with the increase in prior strain, leading to the maximum true strain of 0.279, which is twice that of the as-annealed original one. The sample showed a largely reduced tension-compression yield asymmetry by subjecting to pre-torsion alone or combined with a subsequent annealing. The enhanced ductility and reduced asymmetry are attributed to the development of a gradient microstructure with refined grains, and also randomization of the weakened texture due to torsion and subsequent annealing.

Phase asymmetry of heart rate variability signal

Heart rate asymmetry (HRA) is considered as a physiological phenomenon in healthy subjects. In this article, we propose a novel HRA index, Slope Index (SI), to quantify phase asymmetry of heart rate variability (HRV) system. We assessed the performance of proposed index in comparison with conventional (Guzik's Index (GI) and Porta's Index (PI)) HRA indices. As illustrative examples, we used two case studies: (i) differentiate physiologic RR series from synthetic RR series; and (ii) discriminate arrhythmia subjects from Healthy using beat-to-beat heart rate time series. The results showed that SI is a superior parameter than GI and PI for both case studies with maximum ROC area of 0.84 and 0.82 respectively. In contrast, GI and PI had ROC areas {0.78, 0.61} and {0.50, 0.56} in two case studies respectively. We also performed surrogate analysis to show that phase asymmetry is caused by a physiologic phenomena rather than a random nature of the signal. In conclusion, quantification of phase asymmetry of HRV provides additional information on HRA, which might have a potential clinical use to discriminate pathological HRV in future.

Temporal asymmetry and the self/person split

Derek Parfit’s discussion of our bias towards the future has sparked considerable discussion of our pervasively asymmetrical attitudes towards past and future goods. Much of this discussion has centred on whether we can rationally justify such attitudes or whether they are intrinsically irrational. This paper seeks neither to justify nor to reject temporally asymmetrical attitudes, but to explicate the way perspective, and particularly temporal perspective, operates in such biases, in order to show how our temporal biases point to something important about the structure of selfhood. By employing an emerging distinction in the personal identity literature between the ‘self’ as an intrinsically first personal and temporally indexical locus of consciousness, and the ‘person’ as a diachronic bearer of various forms of physical and psychological predicates, we can see that the clash between temporally asymmetrical attitudes and symmetrical welfare judgments is in fact a result of the ways in which selves and persons interact.

Musculoskeletal asymmetry in football athletes: A product of limb function over time.

PURPOSE: Asymmetrical loading patterns are commonplace in football sports. Our aim was to examine the influence of training age and limb function on lower-body musculoskeletal morphology. METHODS: Fifty-five elite football athletes were stratified into less experienced (≤3 yr; n = 27) and more experienced (>3 yr; n = 28) groups by training age. All athletes underwent whole-body dual-energy x-ray absorptiometry scans and lower-body peripheral quantitative computed tomography tibial scans on the kicking and support limbs. RESULTS: Significant interactions between training age and limb function were evident across all skeletal parameters (F16, 91 = 0.182, P = 0.031, Wilks Λ = 0.969). Asymmetries between limbs were significantly larger in the more experienced players than the less experienced players for tibial mass (P ≤ 0.044, d ≥ 0.50), total cross-sectional area (P ≤ 0.039, d ≥ 0.53), and stress-strain indices (P ≤ 0.050, d ≥ 0.42). No significant asymmetry was evident for total volumetric density. More experienced players also exhibited greater lower-body tibial mass (P ≤ 0.001, d ≥ 1.22), volumetric density (P ≤ 0.009, d ≥ 0.79), cross-sectional area (P ≤ 0.387, d ≥ 0.21), stress-strain indices (P ≤ 0.012, d ≥ 0.69), fracture loads (P ≤ 0.018, d ≥ 0.57), and muscle mass and cross-sectional area (P ≤ 0.016, d ≥ 0.68) than less experienced players. CONCLUSIONS: Asymmetries were evident in athletes as a product of limb function over time. Chronic exposure to routine high-impact gravitational loads afforded to the support limb preferentially improved bone mass and structure (cross-sectional area and cortex thickness) as potent contributors to bone strength relative to the high-magnitude muscular loads predominantly afforded to the kicking limb.

Investigating the changes in heart rate asymmetry (HRA) with perturbation of parasympathetic nervous system

The heart rate asymmetry (HRA) is a disproportionate distribution of heart rate signal. The current study was designed to assess the changes in HRA in experimental conditions using Poincaré plot during parasympathetic blockade (atropine infusion) and parasympathetic enhancement (scopolamine administration). After atropine infusion, the heart rate variability in 5 out of 8 subjects was found asymmetric. In contrast, all 8 subjects were found to be asymmetric during scopolamine administration. The physiological relevance of HRA was demonstrated by showing correlation with standard frequency domain parameters during all phases of the experiment. The deviation of asymmetry index (GI ( p )) from symmetric range was further analyzed, which was maximum during scopolamine administration and minimum during atropine infusion. These findings suggest that parasympathetic block reduces the prevalence of HRA, and has significant correlation of GI ( p ) with frequency domain features of HRV analysis.