Fluctuation Asymmetry Research Articles

Probing Hydrodynamic Fluctuation-Induced Forces with an Oscillating Robot.

We study the dynamics of an oscillating, free-floating robot that generates radially expanding gravity-capillary waves at a fluid surface. In open water, the device does not self-propel; near a rigid boundary, it can be attracted or repelled. Visualization of the wave field dynamics reveals that when near a boundary, a complex interference of generated and reflected waves induces a wave amplitude fluctuation asymmetry. Attraction increases as wave frequency increases or robot-boundary separation decreases. Theory on confined gravity-capillary wave radiation dynamics developed by Hocking in the 1980s captures the observed parameter dependence due to these "Hocking fields." The flexibility of the robophysical system allows detailed characterization and analysis of locally generated nonequilibrium fluctuation-induced forces [M. Kardar and R. Golestanian, Rev. Mod. Phys. 71, 1233 (1999)RMPHAT0034-686110.1103/RevModPhys.71.1233].

Utilizing fluctuation asymmetry to assess the effects of U-238 radioactivity on the marine ecosystem around the Madras nuclear power plant, India

The monitoring of marine ecosystems is crucial due to the growing threat posed by nuclear power plants and other nuclear anthropogenic emissions. In our work, we used a straightforward and low-cost biomonitoring technique called fluctuation asymmetry (FA) to examine the variation between the left and right sides (developmental instability) of organisms’ traits that were influenced by genetic and environmental variables in the early stages of ontogenesis. The specimens of fish (Leiognathus sp.) and crabs (Portunus sanguinolentus) were collected seasonally and used as bioindicators to determine the effects of Uranium-238 (U-238) radioactivity around a nuclear power plant. The obtained results revealed that FA values were not considered typical values (FA = 0) in all seasons. Moreover, FA values of Leiognathus sp. exhibited insignificant fluctuation for a particular characteristic through the different seasons, while a significant fluctuation occurred amongst the characteristics themselves throughout the same season. Inversely, FA values of the four characteristics in Portunus sanguinolentus displayed seasonal variation amongst them all. Statistically, there was a strong positive correlation (r = 0.5, p < 0.05) between U-238 radioactivity in the flesh of both organisms and the fluctuation asymmetry of different traits but it is not a sign that any radioactive pollution exists.

Bilateral fluctuation asymmetry of otoliths of Collichthys lucidus in different functional areas of Haizhou Bay.

The fluctuating asymmetry (FA) of fish otoliths can reflect the difference in the growth and development of fish in sea areas greatly affected by environmental pressure, thus enabling the assessment of different habitats. In this study, using 113 Collichthys lucidus samples collected from different functional areas (estuary area, aquaculture area, artificial reef area and natural area) in Haizhou Bay, the square coefficient of asymmetry variation (CV2 a ) of four characters (length, width, perimeter and area) of the left and right sagittal otoliths was calculated. The results showed that the CV2 a value of otolith width was the lowest and that of otolith length was the highest. The CV2 a value had no obvious regularity with increasing fish body length. In addition, the CV2 a values of the four characteristics reached their lowest values in the artificial reef area, indicating that the construction of marine ranching dominated by artificial reefs may partly improve the aquatic environment in this functional area. We consider that the otolith FA of C. lucidus can be used as a characteristic of environmental stress between different areas/regions/habitats.

An investigation of rotor aeroacoustics with unsteady motions and uncertainty factors

The aeroacoustic characteristics of flying vehicles with pitch-fixed rotors differ from traditional helicopters with pitch-controlled rotor blades. Accurate predictions of rotor noise are still challenging because many uncertainty factors and unsteadinesses exist. This work investigates the aeroacoustic effects of rotational speed deviation, rotation speed fluctuation, blade vibration and blade geometric asymmetry. The analysis is based on the efficient computation of rotor noise under different working conditions. The mean aerodynamic variables are computed using the blade element moment theory, while small-amplitude fluctuations are introduced to account for the unsteadiness and uncertainty factors. It is shown that periodic rotation speed fluctuations and blade vibrations can produce significant extra tones. By contrast, if the fluctuations and vibrations are random, the noise level in a wide frequency range is increased. The intriguing result reminds us of the need to revisit the rotor broadband noise sources commonly attributed to turbulent flows. The influences are observer angle dependent, and the extra noise production is more significant in the upstream and downstream directions. The asymmetric blade geometry can cause extra tonal noise at the harmonics of the blade shaft frequency. The noise features of dual rotors are also investigated. Usually, the noise is sensitive to the initial phase difference and rotation directions due to the interference effect. However, the noise features are vastly altered if there are slight differences in the rotation speeds. Although the influences of some factors on rotor noise were already known, the present study provides a more comprehensive analysis of the problem. The results also highlight the need to consider these practical factors for accurate noise prediction of multi-rotor flying vehicles.

Analysis of aerotechnogenic pollution of the Vinnytsia using phytoindication methods

Today, the anthropogenic impact on the environment is increasing, especially in urbanized areas and territories where active hostilities are taking place. Among a number of urgent environmental problems, it is possible to single out atmospheric air pollution, which occurs as a result of the concentration of road transport and industry in safe areas. The article presents the results of research into the state of atmospheric air pollution in the city of Vinnytsia using phytoindication methods, namely the degree of fluctuating asymmetry of warty birch leaves, and established the dependence of the fluctuating asymmetry on the level of traffic load. The research was conducted at the end of July in 2021 and 2022, after the end of the growing season of warty birch (Betula pendula). In the city of Vinnytsia, six representative experimental sites with different levels of anthropogenic load were identified. Fluctuation asymmetry coefficients of warty birch leaves were calculated for each experimental site and indicators of the asymmetry coefficient were determined. The level of motor vehicle load on experimental sites was established and a correlation-regression model of the dependence of the coefficient of fluctuation asymmetry of the leaves of the warty birch on the level of motor vehicle load was calculated. Conducting biomonitoring of aerotechnogenic pollution of urban ecosystems is necessary for finding ways to optimize its quality.

Assessing Leaf Morphometric Symmetry of Four Chinese Quercus Species in a Mixed Forest

(1) Background: Oaks have achieved notoriety for sufficient levels of sympatric species richness allowing hybridization, thus generating substantial phenotypic variation. Leaf fluctuation asymmetry is an important attribute, as it reflects not only genetic variability but also species buffering capacity. (2) Methods: We investigated the phenotypic diversity of four-oak species (Quercus acutissima, Q. variabilis, Q. fabri, and Q. serrata var. brevipetiolata) using leaf geometric morphometric analysis. Eight leaf morphological indicators (length, width, perimeter, area, left and right areas, areal ratio, and normalized symmetry index) were used to determine the hybridization level, whereas bilateral symmetry indicators were used to assess species environmental adaptation; (3) Results: Phenotypic variation ranged from 1.54 to 29.35 folds and significantly diverged among the studied species. Taxonomically species in Section Quercus (Q. fabri and Q. serrata var. brevipetiolata) are lower than those in Section Cerris (Q. acutissima and Q. variabilis) with good bilateral symmetry. The bilateral symmetry index of Q. variabilis had a larger range of variation, indicating better environmental adaptability; (4) Conclusions: We presume that species in Section Quercus with less leaf fluctuation asymmetry have a high level of genetic heterozygosity; however, this assumption requires further verification. The observed phenotypic diversity reflects a combination of environmental and genetic factors.

Asymmetric Multifractal Cross-Correlations Between Economic Policy Uncertainty and Agricultural Futures Prices

This paper investigates the fluctuation characteristics and asymmetry of cross-correlations between economic policy uncertainty (EPU) and agricultural futures prices in China and the US by using the multifractal detrended cross-correlation analysis (MF-X-DFA) and multifractal asymmetric detrended cross-correlation analysis (MF-ADCCA). We find that the multifractal cross-correlations exist between EPU and agricultural futures prices, and the cross-correlations are anti-persistent and asymmetric. The anti-persistent cross-correlations in China are all stronger than those in the US. The multifractal degree of cross-correlation between EPU and soybean futures price is lower in China than in the US, while the multifractal degree of cross-correlation between EPU and soybean meal, soybean oil or corn futures price is higher in China than in the US. Moreover, China’s soybean futures price is more susceptible to the upward and downward trends in China’s EPU, while the US soybean meal, soybean oil, and corn futures prices are more susceptible to them in the US EPU.

Morphea en coup de sabre and hemifacial atrophy in an interdisciplinary approach

The increase in the degree of fluctuation asymmetry is accompanied, among others, by diseases such as morphea en coup de sabre (morphea ECDS) or Parry‑Romberg syndrome (PHA). Patients suffering from them struggle not only with dermatological defects, but also with neurological, rheumatological, orthopedic, ophthalmological and dental symptoms. Morphological and functional disorders and craniofacial deformities related to them often generate psychosocial problems. The complexity of the issues to be solved proves the necessity of undertaking interdisciplinary actions aimed at developing objective diagnostic and therapeutic protocols, restoring (especially in pediatric patients) as close as possible to the correct developmental patterns, inhibiting the active phase of the disease and undertaking effective and aesthetically satisfying measures.

Sample Size for Bioindication of Pollution Level by the Method of Fluctuating Asymmetry

Bioindication is a convenient tool for assessing the environmental situation and the level of pollution of natural and man-made landscapes. One of the most important indicator is the fluctuating asymmetry of plant organs, less common – organs of animals and humans. In 2019, we studied the fluctuating asymmetry of Pinus sylvestris L. located in the industrial zone (Yanino-1), as well as in city parks of St. Petersburg (Alexandrino, Sergievka) and Moscow (Sokolniki). The dependence of the fluctuation asymmetry on the sample size is studied, the volumes of samples are substantiated, an algorithm for processing experimental data is proposed, which allows increasing the accuracy of experiments, avoids false positive or false

Symmetry or face asymmetry, what is the condition — contemporary opinions of researchers

Symmetry, among others, is the exponent of the correct face structure. 31 publications from the last 5 years were selected from medical databases, which discussed factors that may affect facial symmetry. According to the analyzed reports, the etiology of facial asymmetry is multifactorial through functional, neuromuscular, stomatognathic, environmental, congenital, acquired as a result of injuries, cancer, chronic skin diseases and aging process. Fluctuation asymmetry within the population average does not significantly affect the assessment of facial attractiveness, while a significant degree of fluctuation asymmetry can have a destructive impact on the multi‑faceted quality of life of an individual.

Аssessment of the ecological safety level in the urban ecosystem by the atmospheric air condition

Green plantings, which are a part of the modern city, are an important element creating an environment providing favorable microclimatic and sanitary conditions for human living. Plants of the city streets, which tend to grow near the roadway, play an important role. According to the magnitude of the fluctuation asymmetry of the bilateral morphological features in plant organisms, the main environmental hazards resulting from the complex of emission, background-parametric and landscape-destructive effects associated with the formation of the urban landscape were investigated. It is proposed to determine the state of the urban ecosystem based on the of fluctuation asymmetry (FA) criteria – slight non-directional deviations between the sides of the organ, which are laid during ontogeny. The condition of the small-leaved linden (Tilia cordata) leaf plates was evaluated by the development stability, which characterizes the level of pollution in the urban ecosystem. The nature of industrial emissions into the air basin and water bodies was analyzed, as well as the level of the soil cover contamination due to the deposition of aerosol emissions in the administrative districts of Kyiv. A comprehensive approach was proposed to evaluate the status of urban ecosystems based on the combination of instrumental methods with bioindication research methods. Such a combination will make it possible to classify urban areas with the high probability, first, not by the degree of chemical pollution, but by the degree of anthropogenic changes in a whole set of environmental factors, which play a crucial role in the formation of specific properties of the urban ecosystem.

Morphology of the inferior pharyngeal bones of white bream (Blicca bjoerkna) in River Warta.

The inferior pharyngeal bones are a characteristic feature of the Cyprinidae. Morphology of inferior pharyngeal bones is important in the diagnosis of carnivorous food, or determining the diet of fishes. Due to the lack of literature data, the aim of the study was to examine the morphology of the inferior pharyngeal bone in detail. 102 Blicca bjoerkna specimens caught in the River Warta (Poland) were analysed. 204 inferior pharyngeal bones were collected. The parameters of the inferior pharyngeal bones correlated with the measured head features and the total fish length. The arches of inferior pharyngeal bones did not have directional asymmetry for the two main parameters (height and width of inferior pharyngeal bone). However, there was a left-sided directional asymmetry of the ventral part of inferior pharyngeal bone. In the case of the B.bjoerkna from River Warta, large differences in terms of individual parameters of inferior pharyngeal bones were observed. Fluctuation asymmetry was low. Shape of inferior pharyngeal bones was very round. In total, 12 teeth formulas were described. The 35.29% of the fish had formula different than described in the literature 2.5-5.2 and more teeth in the right arches. Following identification, measurements of the structures enable estimation of the lengths and weights of prey to be determined from biometric relationships. Analysis of body morphological features in combination with pharyngeal bone morphology could show a hybrid in the Warta river's population.

Morphogenetic analysis of the stability of water macrophytes development in the short-term biomonitoring of water ecosystems of the Polissya of Ukraine

This paper substantiates that Morphogenetic changes in some species of plants growing freely within the limits of the Teterevskyi ecological corridor are informative indicators of the sustainable development of aquatic ecosystems, and the regularities of the distribution of the indices of integrated fluctuation asymmetry are a prerequisite for assessing the quality of water in the Polissya area of Ukraine.

Use of the bioindication method of fluctuating asymmetry of the maple leaf (Acer Platanoides L.) for assessing the quality of the enviroment in the populated areas

Such natural sciences as biology, biogeochemistry, ecology and geobotany study and use bioindication. It is a modern new and helpful scientific direction. The methodology of fluctuating asymmetry worked out in the framework of phytoindication is a convenient, cheap and the closest to natural objects tool for studying of macroscopic changes in the development of bioobjects owing to the negative natural and anthropogenic stress effects. Purpose. Evaluation of the quality of the environment on the violation of the bilateral symmetry of the maple leaf and the appearance of a fluctuating asymmetry of the sides of the leaf’s sheet relative to the central vein under the influence of the anthropogenic load. Analysis of well-known evaluation systems for assessing the quality of the environment. Methods. Phytoindication as one of the bioindication methods with using plants (maple leaves). The fluctuating asymmetry method: measuring 4 parameters on the left and right sides of a leaf and defining of the form of a leaf top. Mathematical processing of the results of all measurements (1376 measures) based on the Microsoft Excel program. Results. A statistical evaluation of the leaf measures was made for 7 indices of the central tendency and variability. The fluctuation asymmetry index for the biomaterial of all the investigated sites of six districts in Odessa in the summer period of 2016 was calculated and tested for normal distribution. The quality of the environment is determined using two point systems in the different areas of the resort city and the suburb. Conclusions. Statistical processing of all platelet measurements showed the suitability of using the measured features and the maple leaf itself for the purpose of phytoindication. A greater validity of the G.M. Melkumov’s point system was shown when determining the quality of the environment by the integral fluctuation asymmetry index of the maple leaf. In fact, the industrial zones of the city, its park and central parts have a high degree of pollution, although not reaching a critical level.

Chlorophyll Fluorescence, Fluctuation Asymmetry Parameters And Elemental Analysis In The Leaves Of Olea europea L. Plants in territories Of Baku characterized by various degrees of pollution

Chlorophyll Fluorescence, Fluctuation Asymmetry Parameters And Elemental Analysis In The Leaves Of Olea europea L. Plants in territories Of Baku characterized by various degrees of pollution

Effect of earthquake‐induced axial load fluctuations on asymmetric frame–wall–rocking foundation systems

SummaryFluctuations in axial load imposed on a rocking footing will affect its moment capacity, the shape of its moment–rotation hysteresis, and potentially the system's seismic performance. Structural asymmetry increases the likelihood of axial load variation during earthquake excitations. To investigate this issue, a unique centrifuge testing program was carried out on low‐rise frame–wall–rocking foundation systems. In this paper, the seismic behaviors of asymmetric and symmetric models from this test program are systematically compared. Experimental results reveal that placing the lateral force resisting shear wall outboard produces significant axial load fluctuation, which in turn greatly deteriorate the lateral load‐carrying capacity of a foundation rocking dominated frame–wall system, particularly in its weak direction. However, it strengthens the system when loading is towards the shear wall, leading to a highly asymmetric hysteretic response. During earthquake loading, all asymmetric rocking foundation systems observe smaller peak roof accelerations, but larger peak and permanent roof drifts compared with the symmetric systems. Despite these differences in response, the axial load fluctuation and structural asymmetry do not significantly change the relative energy dissipated by the rocking foundations and inelastic structural components within each frame–wall–rocking foundation model. Copyright © 2015 John Wiley & Sons, Ltd.

Asymmetry Index of Stock Price Fluctuations

Stock price fluctuation asymmetry, the asymmetry between stock price rise and fall speed, is a general feature of stock indices. Based on inverse statistics, a new measurement, named as asymmetry index, is proposed to evaluate this asymmetry. We calculate and compare asymmetry indices of historical prices from ten stock markets. It is found that in most stock markets, price fall is faster than price rise; while in China and India, price rise is generally faster than price fall.

Investors’ risk attitudes and stock price fluctuation asymmetry

Price rise/fall asymmetry, which indicates enduring but modest rises and sudden short-term falls, is a ubiquitous phenomenon in stock markets throughout the world. Instead of the widely used time series method, we adopt inverse statistics from turbulence to analyze this asymmetry. To explore its underlying mechanism, we build a multi-agent model with two kinds of investors, which are specifically referred to as fundamentalists and chartists. Inspired by Kahneman and Tversky’s claim regarding peoples’ asymmetric psychological responses to the equivalent levels of gains and losses, we assume that investors take different risk attitudes to gains and losses and adopt different trading strategies. The simulation results of the model developed herein are consistent with empirical work, which may support our conjecture that investors’ asymmetric risk attitudes might be one origin of rise/fall asymmetry.

Towards a quantum theory of the chiral magnetic effect

We discuss three possible ways to address quantum physics behind chiral magnetic effect and electric charge fluctuation patterns in heavy ion collisions. The first one makes use of P-parity violation probed by local order parameters, the second considers CME in quantum measurement theory framework and the third way is to study P-odd * P-odd contributions to P-even observables. In the latter approach relevant form-factor is extracted and computed for weak magnetic field in confinement region and for free quarks in strong field regime. It is shown that the effect is negligible in the former case. We also discuss saturation effect - charge fluctuation asymmetry for free fermions reaches constant value at asymptotically large fields.

Disentangling fluctuating asymmetry from otolith shape

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 399:261-272 (2010) - DOI: https://doi.org/10.3354/meps08347 Disentangling fluctuating asymmetry from otolith shape M. Palmer*, M. Linde, B. Morales-Nin IMEDEA (CSIC-UIB), Instituto Mediterráneo de Estudios Avanzados, Miquel Marquès 21, 07190 Esporles (Mallorca), Spain *Email: palmer@imedea.uib-csic.es ABSTRACT: Fluctuating asymmetry (FA), defined as random deviations from ideal, perfect symmetry, has been hypothesized to be negatively associated with fitness and positively associated with stress. Fish otoliths deserve special attention in regard to this topic because their FA is relatively easy to measure, unlike the fitness of wild fish themselves. In addition, otoliths are convenient for estimating FA, because they are systematically extracted for aging purposes, and otolith collections might allow the use of FA as a bioindicator of change at different spatio-temporal scales. Here we demonstrate 2 key methodological tools: the use of shape instead of previously used univariate (metric or meristic) traits, and the use of a statistical protocol capable of disentangling true FA from other types of asymmetry (namely, directional asymmetry and antisymmetry) and from measurement error. In the case of the razor fish Xyrichthys novacula; fluctuation asymmetry of the otolith shape of 180 individuals from 5 populations accounted for 23.2% total shape variability (5 fold larger than the measurement error). Moreover, FA clearly differed between populations. In contrast, FA measured using a univariate trait (radius at the sulcus) did not detect between-population differences. Moreover, in a simulation experiment, we demonstrate that FA measured using shape is able to reveal a true pattern, while FA measured using a univariate trait extracted from the same data is unable to do so. Therefore, the analysis of FA using shape paired with an adequate statistical model may increase our knowledge of the potential links between otolith FA and fitness or stress. KEY WORDS: Fluctuating asymmetry · Shape · Geometric morphometrics · Two-factor mixed effects model · Procrustes ANOVA · Directional asymmetry Full text in pdf format PreviousNextCite this article as: Palmer M, Linde M, Morales-Nin B (2010) Disentangling fluctuating asymmetry from otolith shape. Mar Ecol Prog Ser 399:261-272. https://doi.org/10.3354/meps08347 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 399. Online publication date: January 28, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.