WorldWideScience

Sample records for wing fluctuating asymmetry

  1. Constant fluctuating asymmetry but not directional asymmetry along the geographic distribution of Drosophila antonietae (Diptera, Drosophilidae

    Directory of Open Access Journals (Sweden)

    Marcelo Costa

    2015-12-01

    Full Text Available ABSTRACT The population dynamics of a species tends to change from the core to the periphery of its distribution. Therefore, one could expect peripheral populations to be subject to a higher level of stress than more central populations (the center–periphery hypothesis and consequently should present a higher level of fluctuating asymmetry. To test these predictions we study asymmetry in wing shape of five populations of Drosophila antonietae collected throughout the distribution of the species using fluctuating asymmetry as a proxy for developmental instability. More specifically, we addressed the following questions: (1 what types of asymmetry occur in populations of D. antonietae? (2 Does the level of fluctuating asymmetry vary among populations? (3 Does peripheral populations have a higher fluctuating asymmetry level than central populations? We used 12 anatomical landmarks to quantify patterns of asymmetry in wing shape in five populations of D. antonietae within the framework of geometric morphometrics. Net asymmetry – a composite measure of directional asymmetry + fluctuating asymmetry – varied significantly among populations. However, once net asymmetry of each population is decomposed into directional asymmetry and fluctuating asymmetry, most of the variation in asymmetry was explained by directional asymmetry alone, suggesting that populations of D. antonietae have the same magnitude of fluctuating asymmetry throughout the geographical distribution of the species. We hypothesize that larval development in rotting cladodes might play an important role in explaining our results. In addition, our study underscores the importance of understanding the interplay between the biology of a species and its geographical patterns of asymmetry.

  2. Mercury exposure may influence fluctuating asymmetry in waterbirds

    Science.gov (United States)

    Herring, Garth; Eagles-Smith, Collin A.; Ackerman, Joshua T.

    2017-01-01

    Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds.

  3. Mercury exposure may influence fluctuating asymmetry in waterbirds.

    Science.gov (United States)

    Herring, Garth; Eagles-Smith, Collin A; Ackerman, Joshua T

    2017-06-01

    Variation in avian bilateral symmetry can be an indicator of developmental instability in response to a variety of stressors, including environmental contaminants. The authors used composite measures of fluctuating asymmetry to examine the influence of mercury concentrations in 2 tissues on fluctuating asymmetry within 4 waterbird species. Fluctuating asymmetry increased with mercury concentrations in whole blood and breast feathers of Forster's terns (Sterna forsteri), a species with elevated mercury concentrations. Specifically, fluctuating asymmetry in rectrix feather 1 was the most strongly correlated structural variable of those tested (wing chord, tarsus, primary feather 10, rectrix feather 6) with mercury concentrations in Forster's terns. However, for American avocets (Recurvirostra americana), black-necked stilts (Himantopus mexicanus), and Caspian terns (Hydroprogne caspia), the authors found no relationship between fluctuating asymmetry and either whole-blood or breast feather mercury concentrations, even though these species had moderate to elevated mercury exposure. The results indicate that mercury contamination may act as an environmental stressor during development and feather growth and contribute to fluctuating asymmetry of some species of highly contaminated waterbirds. Environ Toxicol Chem 2017;36:1599-1605. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America. Published 2016 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

  4. Fluctuating Asymmetry of Human Populations: A Review

    Directory of Open Access Journals (Sweden)

    John H. Graham

    2016-12-01

    Full Text Available Fluctuating asymmetry, the random deviation from perfect symmetry, is a widely used population-level index of developmental instability, developmental noise, and robustness. It reflects a population’s state of adaptation and genomic coadaptation. Here, we review the literature on fluctuating asymmetry of human populations. The most widely used bilateral traits include skeletal, dental, and facial dimensions; dermatoglyphic patterns and ridge counts; and facial shape. Each trait has its advantages and disadvantages, but results are most robust when multiple traits are combined into a composite index of fluctuating asymmetry (CFA. Both environmental (diet, climate, toxins and genetic (aneuploidy, heterozygosity, inbreeding stressors have been linked to population-level variation in fluctuating asymmetry. In general, these stressors increase average fluctuating asymmetry. Nevertheless, there have been many conflicting results, in part because (1 fluctuating asymmetry is a weak signal in a sea of noise; and (2 studies of human fluctuating asymmetry have not always followed best practices. The most serious concerns are insensitive asymmetry indices (correlation coefficient and coefficient of indetermination, inappropriate size scaling, unrecognized mixture distributions, inappropriate corrections for directional asymmetry, failure to use composite indices, and inattention to measurement error. Consequently, it is often difficult (or impossible to compare results across traits, and across studies.

  5. Methods of statistical analysis of fluctuating asymmetry

    Directory of Open Access Journals (Sweden)

    Zorina Anastasia

    2012-10-01

    Full Text Available Methodical problems concerning the practical use of fluctuating asymmetry level of bio-objects are considered. The questions connected with the variety of value asymmetry calculation methods and the use of asymmetry indicators efficiency and integrated indexes are discussed in detail. Discrepancy of research results when using several estimates of asymmetry is connected with their statistical properties and peculiarity of their normal variability which define sensitivity and operability of indicators. Concrete examples illustrating the negative influence of arithmetic transformations on the revealing properties of indicators are given: disturbance of normal distribution and the need of using rough nonparametric criteria , the increase of the importance of rare casual deviations, the introduction of additional variability components into an asymmetry level. Problems which arise in calculating asymmetry integrated indexes when signs unite with different levels of statistical parameters are separately considered. It is recommended to use the indicator of fluctuating asymmetry based on normalized deviation.

  6. Associations among fluctuating asymmetry, tonic immobility duration, and flight distance or ease of capture in chickens.

    Science.gov (United States)

    Campo, J L; Dávila, S G; Prieto, M T; Gil, M G

    2012-07-01

    The purpose of this study was to analyze the associations among fluctuating asymmetry, duration of tonic immobility, and flight performance or ease of capture in chickens. Cocks (n = 220; 36 wk old) from 10 Spanish breeds and a White Leghorn population were used. The quantitative/qualitative relationship among fluctuating asymmetry, duration of tonic immobility, and landing accuracy (good or bad) or landing distance (long or short), and the quantitative/quantitative relationship among fluctuating asymmetry, duration of tonic immobility, and time of capture or number of attempts of capture were studied. Relative fluctuating asymmetry of toe length, wing length, and the combined relative asymmetry of toe length, leg length, wing length, and leg width was significantly greater (P distance and smaller in cocks with long landing distance. There was a significant difference for the duration of tonic immobility between groups of cocks with short or long landing distance (P distance being longer. There was no significant correlation among relative fluctuating asymmetry, duration of tonic immobility, and time of capture or attempts of capture. Associations between morphological values of toe, leg, and wing and flight performance or ease of capture were not significant. Thus, birds with less asymmetry and fear level have better flight performance than more asymmetric and fearful birds, whereas the ease of capture is not associated with fearfulness and asymmetry.

  7. Investigation of asymmetry of vortex flow over slender delta wings

    Science.gov (United States)

    Atashbaz, Ghasem

    Vortex flow, a major area of interest in fluid mechanics, is widespread in nature and in many man-made fluid mechanical devices. It can create havoc as cyclones or tornadoes or have significant implications in the performance of turbo-fluid machines or supersonic vehicles and so forth. Asymmetric vortices can cause a loss of lift and increase in rolling moment which can significantly affect wing stability and control. Up until the early nineties, it was generally believed that vortex asymmetry was the result of vortex interactions due to the close proximity of vortices over slender delta wings. However, some recent studies have thrown considerable doubt on the validity of this hypothesis. As a result, wind tunnel investigations were conducted on a series of nine delta wing planforms with sharp and round leading edges to examine the occurrence of vortex asymmetry at different angles of attack and sideslip. The study included surface oil and laser light sheet flow visualization in addition to surface pressure and hot-wire velocity measurements under static conditions. The effects of incidence, sideslip and sweep angles as well as Reynolds number variations were investigated. In this study, it was found that the effect of apex and leading edge shape played an important role in vortex asymmetry generation at high angle of attack. Vortex asymmetry was not observed over slender sharp leading edge delta wings due to the separation point being fixed at the sharp leading edge. Experimental results for these wings showed that the vortices do not impinge on one another because they do not get any closer beyond a certain value of angle of attack. Thus vortex asymmetry was not generated. However, significant vortex asymmetry was observed for round leading-edged delta wings. Asymmetric separation positions over the round leading edge was the result of laminar/turbulent transition which caused vortex asymmetry on these delta wing configurations. Sideslip angle and vortex

  8. A new genus of long-legged flies displaying remarkable wing directional asymmetry.

    OpenAIRE

    Runyon, Justin B; Hurley, Richard L

    2004-01-01

    A previously unknown group of flies is described whose males exhibit directional asymmetry, in that the left wing is larger than, and of a different shape from, the right wing. To our knowledge, wing asymmetry of this degree has not previously been reported in an animal capable of flight. Such consistent asymmetry must result from a left-right axis during development, a level of differentiation whose existence has been questioned for insects. Wing asymmetry of this magnitude has implications ...

  9. Fluctuating asymmetry in Apis mellifera(Hymenoptera: Apidae as bioindicator of anthropogenic environments

    Directory of Open Access Journals (Sweden)

    Lorena Andrade Nunes

    2015-09-01

    Full Text Available The successful distribution of A. melliferais due to their ability to adjust to seasonal variations, considerable control over their internal physical environment and exploration of different resources. However, their populations have experienced different forms and levels of environmental pressure. This research aimed to verify the phenotypic plasticity in both size and shape of wings in A. melliferausing fluctuating asymmetry, based on geometric morphometrics from apiaries located in sites with high and low levels of anthropization. We sampled 16 locations throughout all five geographic regions of Brazil. At each site, samples were collected from 20 beehives installed in apiaries: 10 installed near high anthropogenic environments (Cassilàndia - MS, Fortaleza - CE, Maringá - PR, Aquidauana - MS, Rolim de Moura - RO, Riachuelo - SE, Ubirata - PR and Piracicaba - SP, and 10 in sites with low levels of human disturbance (Cassilàndia - MS, Itapiúna CE, Uniao da Vitoria - PR, Aquidauana - MS, Rolim de Moura - RO, Pacatuba - SE, Erval Seco - RS, Rio Claro - SP. A sample of 10 individuals was taken in each hive, totaling 200 per location, for a total of 1 600 individuals. We used fluctuating asymmetry (FA in size and shape of the forewing through geometric morphometrics. The FA analysis was conducted in order to check bilateral differences. The indexes of size and shape were submitted to analysis of variance (ANOVA, where the characters evaluated were used as factors to verify the size and shape differences. The results indicated an asymmetry on the shape of the wing (P < 0.001 but no asymmetry was observed on wing size. Considering FA as an environmental response and high and low impacted areas as a fixed factor, we observed significant differences (P < 0.05. The results for the wing shape in A. melliferademonstrated that this feature undergoes more variation during ontogeny compared to the variation in size. We concluded that bee samples

  10. A new genus of long-legged flies displaying remarkable wing directional asymmetry

    Science.gov (United States)

    Justin B. Runyon; Richard L. Hurley

    2004-01-01

    A previously unknown group of flies is described whose males exhibit directional asymmetry, in that the left wing is larger than, and of a different shape from, the right wing. To our knowledge, wing asymmetry of this degree has not previously been reported in an animal capable of flight. Such consistent asymmetry must result from a left­right axis during development...

  11. Effect of directional selection for body size on fluctuating asymmetry ...

    Indian Academy of Sciences (India)

    Variation in the subtle differences between the right and left sides of bilateral characters or fluctuating asymmetry (FA) has been considered as an indicator of an organism's ability to cope with genetic and environmental stresses during development. However, due to inconsistency in the results of empirical studies, the ...

  12. Effect of directional selection for body size on fluctuating asymmetry ...

    Indian Academy of Sciences (India)

    Madhsudhan

    Over the past three decades, fluctuating asymmetry (FA, small random deviations from perfect bilateral symmetry,. Van Valen [1962]) has received special attention in ecological and evolutionary studies. This is due to the resurgence of interest in FA as an indicator of genetic or environmental stress (Parsons 1990, 1992), ...

  13. Nonlinear growth dynamics and the origin of fluctuating asymmetry

    Science.gov (United States)

    Emlen, J.M.; Freeman, D.C.; Graham, J.H.

    1993-01-01

    The nonlinear, complex nature of biosynthesis magnifies the impacts of small, random perturbations on organism growth, leading to distortions in adaptive allometries and, in particular, to fluctuating asymmetry. These distortions can be partly checked by cell-cell and inter-body part feedback during growth and development, though the latter mechanism also may lead to complex patterns in right-left asymmetry. Stress can be expected to increase the degree to which random growth perturbations are magnified and may also result in disruption of the check mechanisms, thus exaggerating fluctuating asymmetry.The processes described not only provide one explanation for the existence of fluctuating asymmetry and its augmentation under stress, but suggest additional effects of stress as well. Specifically, stress is predicted to lead to decreased fractal dimension of bone sutures and branching structures in animals, and in increased dimension of growth trace patterns such as those found in mollusc shells and fish otoliths and scales.A basic yet broad primer on fractals and chaos is provided as background for the theoretical development in this manuscript.

  14. Fluctuations, conformational asymmetry and block copolymer phase behaviour

    DEFF Research Database (Denmark)

    Bates, F.S.; Schulz, M.F.; Khandpur, A.K.

    1994-01-01

    ) and a bicontinuous cubic morphology with Ia ($) over bar 3d space group symmetry. Two non-classical parameters, epsilon and ($) over bar N, control the occurrence and distribution of these phases, in addition to the classical variables f and N-chi, where f, chi and N are the composition, segment-segment interaction...... parameter and degree of polymerization, respectively. epsilon accounts for differences in the conformational and volume-filling characteristics of each block. Conformational asymmetry, epsilon not equal 1, produces an asymmetric phase diagram around f = 1/2. The importance of fluctuation effects...... are inversely related to the magnitude of ($) over bar N, a type of Ginzburg parameter that is proportional to N. As ($) over bar N decreases, the bicontinuous Ia ($) over bar 3d phase appears adjacent to the ODT. Development of this cubic phase can be rationalized based on chain-packing frustration near...

  15. Quantitative-genetic analysis of wing form and bilateral asymmetry ...

    Indian Academy of Sciences (India)

    Unknown

    Overall wing size was analysed here using centroid size. (defined as the square root of the sum .... For those isochromosomal lines that were common to both experimental temperatures .... subobscura reared at 18ºC. CS refers to centroid size (values in pixels2; 1 mm = 144 pixels), and WS to wing shape (all values ×. 104).

  16. Fluctuating dermatoglyphic asymmetries in youth at ultrahigh-risk for psychotic disorders.

    Science.gov (United States)

    Russak, Olivia Diane Fern; Ives, Lindsay; Mittal, Vijay A; Dean, Derek J

    2016-02-01

    Fluctuating dermatoglyphic asymmetry represents one specific class of minor physical anomaly that has been proposed to reflect prenatal insult and vulnerability to psychosis. However, very little is known about fluctuating dermatoglyphic asymmetry in youth showing symptoms of ultrahigh risk (UHR) for psychosis. Using high-resolution photographs of fingerprints and clinical interviews, the UHR group in this study showed greater fluctuating dermatoglyphic asymmetry compared to controls; however, this was not further linked to symptomatology. The results of this study provide an important perspective on potential biomarkers and support neurodevelopmental conceptions of psychosis. Published by Elsevier B.V.

  17. European economic integration and (A)symmetry of macroeconomic fluctuations

    NARCIS (Netherlands)

    Kool, C.J.M.; Economidou, C.

    2007-01-01

    This paper empirically investigates output and consumption asymmetries in the Eurozone and enlarged EU over the period 1992-2007, and their consequences for monetary policy. Our results reveal that the introduction of the euro has little impact on output asymmetry so far; however, it has led to

  18. Investors’ risk attitudes and stock price fluctuation asymmetry

    Science.gov (United States)

    Zhang, Yu; Li, Honggang

    2011-05-01

    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.

  19. Socioeconomic Status Is Not Related with Facial Fluctuating Asymmetry: Evidence from Latin-American Populations.

    Science.gov (United States)

    Quinto-Sánchez, Mirsha; Cintas, Celia; Silva de Cerqueira, Caio Cesar; Ramallo, Virginia; Acuña-Alonzo, Victor; Adhikari, Kaustubh; Castillo, Lucía; Gomez-Valdés, Jorge; Everardo, Paola; De Avila, Francisco; Hünemeier, Tábita; Jaramillo, Claudia; Arias, Williams; Fuentes, Macarena; Gallo, Carla; Poletti, Giovani; Schuler-Faccini, Lavinia; Bortolini, Maria Cátira; Canizales-Quinteros, Samuel; Rothhammer, Francisco; Bedoya, Gabriel; Rosique, Javier; Ruiz-Linares, Andrés; González-José, Rolando

    2017-01-01

    The expression of facial asymmetries has been recurrently related with poverty and/or disadvantaged socioeconomic status. Departing from the developmental instability theory, previous approaches attempted to test the statistical relationship between the stress experienced by individuals grown in poor conditions and an increase in facial and corporal asymmetry. Here we aim to further evaluate such hypothesis on a large sample of admixed Latin Americans individuals by exploring if low socioeconomic status individuals tend to exhibit greater facial fluctuating asymmetry values. To do so, we implement Procrustes analysis of variance and Hierarchical Linear Modelling (HLM) to estimate potential associations between facial fluctuating asymmetry values and socioeconomic status. We report significant relationships between facial fluctuating asymmetry values and age, sex, and genetic ancestry, while socioeconomic status failed to exhibit any strong statistical relationship with facial asymmetry. These results are persistent after the effect of heterozygosity (a proxy for genetic ancestry) is controlled in the model. Our results indicate that, at least on the studied sample, there is no relationship between socioeconomic stress (as intended as low socioeconomic status) and facial asymmetries.

  20. Climatic and anthropic influence on size and fluctuating asymmetry of Euglossine bees (Hymenoptera, Apidae) in a semideciduous seasonal forest reserve.

    Science.gov (United States)

    Silva, M C; Lomônaco, C; Augusto, S C; Kerr, W E

    2009-01-01

    We examined the influence of climate and man on size and fluctuating asymmetry in two species of Euglossine bees collected from a semideciduous forest reserve. Sixty males of each species were collected; four measurements were made of their wings to obtain a multivariable size index and a fluctuating asymmetry index. No significant differences in the size of Eulaema nigrita Lepeletier were found between the areas and seasons. Larger males of Euglossa pleosticta Dressler were collected during the hot and wet season; however, male size did not vary with location. Higher rainfall and a consequent increase in food availability could have influenced the increase in size of E. pleosticta. Bees collected during the hot and wet season at the forest border were more asymmetric than bees collected during the cold and dry season; the latter were found inside the forest. This indicates that climate and anthropic interferences influence the stability of development of E. pleosticta. Consequently, this species could be used as a bioindicator of stress. Apparently, E. nigrita is more resistant to environmental interference.

  1. [Symmetry is beauty - or is it? The rise and fall of fluctuating asymmetry].

    Science.gov (United States)

    Debat, Vincent

    Fluctuating asymmetry is the stochastic, minor deviation from perfect symmetry in bilaterally symmetrical organisms. It reflects the limit of developmental precision. Such a precision can be influenced by various factors, both internal (genetic mutations, stochastic variation at every levels of development) and external (environmental influences). Fluctuating asymmetry has receive an extreme attention for the past few decades, that culminated in the 90s: it has been used as an estimator of heterozygosity, fitness, environmental stress, and widely applied to human biology, sociobiology and psychology before being more or less discredited in the early 2000s. The reasons for such an extreme popularity and then disgrace are discussed here. Far from suggesting to abandon the study of fluctuating asymmetry, we indicate some of the most promising research avenues. ‡. © 2016 médecine/sciences – Inserm.

  2. Fluctuating Asymmetry of Red Tilapia (Oreochromis niloticus in Genteng Fish Hatchery Center, Banyuwangi

    Directory of Open Access Journals (Sweden)

    Darmawan Setia Budi

    2017-05-01

    Full Text Available Fluctuating asymmetry of bilateral meristic characteristic is one of the simple methods that can be used to determine the stability of an individual fish development. This study aims to provide quantitative information about the level of asymmetry red tilapia (Oreochromis niloticus in Genteng Fish Hatchery Center through bilateral meristic characteristic observation. The number of fish used in this study is 100 fish which have a measurement of 5-7 cm. Bilateral meristic characteristic observed is the number of soft pectoral fins, the number of soft pelvic fins, and the number of scales on the lateral line. The results show that the highest value of the fluctuating asymmetry magnitude (FAm and fluctuating asymmetry number (FAn are obtained at the number of scales on the lateral line those are 3.71 and 0.86. Furthermore, on soft pectoral fins, the FAm value obtained is 1.29 and the FAn value is 0.58. Meanwhile, the lowest FAm and FAn values obtained from the soft ventral fins which are 0.93 and 0.50. The overall FAm value is 5.93 and the overall FAn value is 1.94.

  3. No increase in fluctuating asymmetry in ground beetles (Carabidae) as urbanisation progresses

    DEFF Research Database (Denmark)

    Elek, Zoltán; Lövei, Gabor L; Batki, Marton

    2014-01-01

    fluctuating asymmetry in three common predatory ground beetles, Carabus nemoralis, Nebria brevicollis and Pterostichus melanarius. Eight metrical (length of the second and third antennal segments, elytral length, length of the first tarsus segment, length of the first and second tibiae, length of the proximal......Environmental stress can lead to a reduction in developmental homeostasis, which could be reflected in increased variability of morphological traits. Fluctuating asymmetry (FA) is one possible manifestation of such a stress, and is often taken as a proxy for individual fitness. To test...... the usefulness of FA in morphological traits as an indicator of environmental quality, we studied the effect of urbanisation on FA in ground beetles (Carabidae) near a Danish city. First, we performed a critical examina- tion whether morphological character traits suggested in the literature displayed true...

  4. No increase in fluctuating asymmetry in ground beetles (Carabidae) as urbanisation progresses

    DEFF Research Database (Denmark)

    Elek, Zoltán; Lövei, Gabor L; Batki, Marton

    2014-01-01

    fluctuating asymmetry in three common predatory ground beetles, Carabus nemoralis, Nebria brevicollis and Pterostichus melanarius. Eight metrical (length of the second and third antennal segments, elytral length, length of the first tarsus segment, length of the first and second tibiae, length of the proximal...... and distal spines on the first femurs) and one meristic (the number of spines on the second tibiae) traits were examined. Most of them showed FA but not consistently. Females generally displayed a higher level of FA than males. Finally, we examined the changes in the level of FA in bilateral morphological......Environmental stress can lead to a reduction in developmental homeostasis, which could be reflected in increased variability of morphological traits. Fluctuating asymmetry (FA) is one possible manifestation of such a stress, and is often taken as a proxy for individual fitness. To test...

  5. Translational and fluctuating asymmetry as tools to detect stress in stress-adapted and nonadapted plants

    Science.gov (United States)

    Alados, C.L.; Navarro, T.; Escos, J.; Cabezudo, B.; Emlen, J.M.

    2001-01-01

    Plants having experienced previous exposure to a stress are expected to be more resistant to further stress than those not having been exposed. While the assessment of stress in plants is a difficult task, particularly for stress-adapted plants, developmental instability has proven a useful tool for assessing stress in organisms. We examined the effect of water availability on developmental instability (translational asymmetry and fluctuating asymmetry) and growth of Anthyllis cytisoides L. under a precipitation gradient. We compared A. cytisoides in very xeric (Almeri??a, 256 mm of average rainfall) and subhumid (Ma??laga, 613 mm of average rainfall) areas, from north- and south-facing slopes, after both a period of extreme drought (1995) and a humid period (1997). Translational symmetry varied between north- and south-exposed plants but differently for the Almeri??a and Ma??laga populations. We observed that developmental stability was enhanced in south-exposed plants in the population from the more xeric habitat (Almeri??a) after both dry and humid periods. In contrast, A. cytisoides living in a subhumid habitat did not alter their developmental stability in response to exposure after a humid period but exhibited a decline in stability in south-exposed slopes after a dry period. That is interpreted as a consequence of the adaptation of A. cytisoides to aridity. Growth patterns were also investigated. By reducing growth, plants can mitigate stress through a reduction of water and nutrient demands, allowing the maintenance of a steady supply of nutrients for developmental stability. This strategy was followed by plants acclimated to drought. But in mild weather, such as that of Montes de Ma??laga, a high growth rate cannot be supported when water is scarce. We also observed that floral fluctuating asymmetry was greatest on north-facing slopes at both the Almeri??a and Ma??laga sites. That is, southern exposure enhanced floral homeostasis during development

  6. Directional and fluctuating asymmetry in finger and a-b ridge counts in psychosis: a case-control study

    Directory of Open Access Journals (Sweden)

    Fañanás Lourdes

    2003-03-01

    Full Text Available Abstract Background Several studies have reported alterations in finger and a-b ridge counts, and their derived measures of asymmetry, in schizophrenia compared to controls. Because ridges are fully formed by the end of the second trimester, they may provide clues to disturbed early development. The aim of this study was to assess these measures in a sample of patients with psychosis and normal controls. Methods Individuals with psychosis (n = 240, and normal controls (n = 228 were drawn from a catchment-area case-control study. Differences in finger and a-b ridge count and Fluctuating Asymmetry were assessed in three group comparisons (non-affective psychosis versus controls; affective psychosis versus controls; non-affective psychosis versus affective psychosis. The analyses were performed separately for males and females. Results There were no significant group differences for finger nor a-b ridge counts. While there were no group difference for Directional Asymmetry, for Fluctuating Asymmetry measures men with non-affective psychosis had significantly higher fluctuating asymmetry of the index finger ridge count (a when compared to controls (FA-correlation score, p = 0.02, and (b when compared to affective psychosis (adjusted FA-difference score, p = 0.04. Conclusion Overall, measures of finger and a-b ridge counts, and their derived measures of directional and fluctuating asymmetry were not prominent features of psychosis in this sample. While directional asymmetry in cerebral morphology is reduced in schizophrenia, this is not reflected in dermatoglyphic variables.

  7. Directional and fluctuating asymmetry in finger and a-b ridge counts in psychosis: a case-control study

    Science.gov (United States)

    Saha, Sukanta; Loesch, Danuta; Chant, David; Welham, Joy; El-Saadi, Ossama; Fañanás, Lourdes; Mowry, Bryan; McGrath, John

    2003-01-01

    Background Several studies have reported alterations in finger and a-b ridge counts, and their derived measures of asymmetry, in schizophrenia compared to controls. Because ridges are fully formed by the end of the second trimester, they may provide clues to disturbed early development. The aim of this study was to assess these measures in a sample of patients with psychosis and normal controls. Methods Individuals with psychosis (n = 240), and normal controls (n = 228) were drawn from a catchment-area case-control study. Differences in finger and a-b ridge count and Fluctuating Asymmetry were assessed in three group comparisons (non-affective psychosis versus controls; affective psychosis versus controls; non-affective psychosis versus affective psychosis). The analyses were performed separately for males and females. Results There were no significant group differences for finger nor a-b ridge counts. While there were no group difference for Directional Asymmetry, for Fluctuating Asymmetry measures men with non-affective psychosis had significantly higher fluctuating asymmetry of the index finger ridge count (a) when compared to controls (FA-correlation score, p = 0.02), and (b) when compared to affective psychosis (adjusted FA-difference score, p = 0.04). Conclusion Overall, measures of finger and a-b ridge counts, and their derived measures of directional and fluctuating asymmetry were not prominent features of psychosis in this sample. While directional asymmetry in cerebral morphology is reduced in schizophrenia, this is not reflected in dermatoglyphic variables. PMID:12659652

  8. Thermally induced chronic developmental stress in coho salmon: Integrating measures of mortality, early growth and fluctuating asymmetry

    Science.gov (United States)

    Campbell, W.B.; Emlen, J.M.; Hershberger, W.K.

    1998-01-01

    Developmental stability, or homeostasis, facilitates the production of consistent phenotypes by buffering against stress. Fluctuating asymmetry is produced by developmental instability and is manifested as small random departures from bilateral symmetry. Increased fluctuating asymmetry is thought to parallel compromised fitness, in part, because stress promotes energy dissipation. Compensatory energy expenditures within the organism are required to complete development, thus promoting instability through reductions in homeostasis. Increased heterozygosity may enhance developmental stability by reducing energy dissipation from stress through increased metabolic efficiency, possibly by providing greater flexibility in metabolic pathways. Traditionally, fluctuating asymmetry has been used as a bioindicator of chronic stress, provided that selective mortality of less fit individuals did not reduce stress-mediated increases in fluctuating asymmetry to background levels produced by natural developmental error, or create data inconsistencies such as higher asymmetry in groups exposed to lower stress. Unfortunately, absence of selective mortality and its effects, while often assumed, can be difficult to substantiate. We integrated measures of early growth, mortality, fluctuating asymmetry (mandibular pores, pectoral finrays, pelvic finrays, and gillrakers on the upper and lower arms of the first branchial arch) and directional asymmetry (branchiostegal rays) to assess chronic thermal stress (fluctuating temperatures as opposed to ambient temperatures) in developing eggs from two different coho salmon (Oncorhynchus kisutch) stocks and their reciprocal hybrids. Hybridization provided insight on the capacity of heterozygosity to reduce stress during development. Although egg losses were consistently higher in crosses exposed to fluctuating temperatures, egg mortality was predominantly a function of maternal stock of origin. Post-hatch losses were higher in crosses exposed to

  9. Fluctuating and directional asymmetry in young human males: effect of heavy working condition and socioeconomic status.

    Science.gov (United States)

    Ozener, Bariş

    2010-09-01

    Many adverse environmental and genetic factors can affect stability of development during human growth. Although the level of fluctuating asymmetry (FA) may be influenced by environmental and genetic stress encountered during this period, directional asymmetry (DA) is largely attributable to differential mechanical loading during bone growth, for example, handedness. I assessed the effects of heavy working conditions and socioeconomic conditions on asymmetry levels in three groups of young human males: 1) individuals employed in the heavy industry sector (n = 104, mean age = 18.48 +/- 0.61 years), 2) individuals who had the same socioeconomic status as the laborers (n = 102, mean age = 18.39 +/- 0.58 years) but were not laborers, and 3) nonlaborers from the higher socioeconomic levels of society (n = 103, mean age = 18.43 +/- 0.67). For all subjects, hand length, hand width, elbow width, wrist width, knee width, ankle width, foot length, foot width, ear length, and ear width were measured. All measurements of the upper extremities in the labor group appeared to exhibit DA; in the other two groups only hand measurements exhibited DA. According to analysis of FA, subjects living in poor conditions exhibited more FA than their nonlaborer peers living in better conditions. In addition, biomechanical pressures due to heavy working conditions of the labor group appeared to cause increased DA in the upper extremities: DA increased with an increase in the number of years working.

  10. Does fluctuating asymmetry of antlers in white-tailed deer (Odocoileus virginianus) follow patterns predicted for sexually selected traits?

    Science.gov (United States)

    Ditchkoff, S.S.; Lochmiller, R.L.; Masters, R.E.; Starry, W.R.; Leslie, David M.

    2001-01-01

    Secondary sexual characters have been hypothesized to signal male quality and should demonstrate a negative relationship between the size of the trait and degree of fluctuating asymmetry because they are costly to produce. We collected morphometric and antler data from 439 white-tailed deer (Odocoileus virginianus) in Oklahoma, USA, in order to determine whether measures of antler asymmetry follow the patterns predicted for sexually selected characters. Relative fluctuating asymmetry was negatively related to antler size for all deer and within age groups up to five and a half years of age. We did not detect an association between asymmetry and antler size among deer that were six and a half years or older. When categorizing deer by antler size, we found that deer with small antlers (???33rd percentile) had greater levels of relative asymmetry than deer with large antlers (???67th percentile). The relative asymmetry of antlers was negatively related to age and was greatest in deer that were one and a half years old. Relative asymmetry was also negatively related to carcass mass, inside spread, skull length and body length. These data suggest that asymmetry in the antlers of white-tailed deer may be a reliable signal of quality and, as such, may be important in maintaining honesty in intrasexual advertisements during the breeding season.

  11. Fluctuating Asymmetry of Craniological Features of Small Mammals as a Reflection of Heterogeneity of Natural Populations

    Directory of Open Access Journals (Sweden)

    Elena Shadrina

    2016-11-01

    Full Text Available Fluctuating asymmetry (FA in nine species of small mammals (Insectivora and Rodentia was estimated using 10 cranial features (foramina for nerves and blood vessels. The main criterion was the occurrence of the fluctuating asymmetry manifestations (OFAM. A total of 2300 skulls collected in the taiga and forest-tundra of Yakutia (Northeast Asia were examined. The examined species are characterized by comparable OFAM values in the vast territories of the taiga zone; on the ecological periphery of the range an increased FA level is registered. Asymmetric manifestations in analyzed features are equally likely to occur in males and females. OFAM values in juveniles are higher than in adults; this difference is more pronounced on the periphery of the geographic range. Among juveniles, lower FA levels are observed in individuals that have bred. It can be surmised that the risk of elimination of individuals with high FA levels increases in stressful periods (active reproduction and winter. In conditions that are close to optimal, populations demonstrate relatively homogeneous FA levels, while on the periphery of the area an increase in occurrence of disturbances in developmental stability is observed, which leads, on one hand, to higher average FA for the population and, on the other hand, to heterogeneity of the population in this parameter.

  12. Fluctuating asymmetry in Pelophylax ridibundus (Amphibia: Ranidae as a response to anthropogenic pollution in south Bulgaria

    Directory of Open Access Journals (Sweden)

    Zhelev Zhivko M.

    2015-01-01

    Full Text Available The aim of this study was to investigate the integral indicator for developmental stability, the fluctuating asymmetry (FA, in the marsh frog Pelophylax ridibundus populations that inhabit biotopes of different types (running rivers and still, dam lakes, when exposed to different types of anthropogenic pollution (domestic sewage pollution and heavy metal pollution in south Bulgaria. A total of 920 P. ridibundus individuals were used for FA analyses over three years (2009-2011. Fluctuating asymmetry was defined by 10 morphological traits, using the index frequency of asymmetric manifestation of an individual (FAMI. In closed water basins, regardless of the nature of toxicants, the FA values in P. ridibundus populations were statistically lower than those in river populations. The FA values were constantly the highest under conditions of sustained anthropogenic pollution, with high concentrations of toxicants in rivers with domestic sewage pollution and heavy-metal pollution. The results provide better opportunities to use FA in P. ridibundus populations for bioindication and biomonitoring, and for parallel and independent analyses of the physicochemical assessment of the environmental condition.

  13. The asymmetry of the carpal joint and the evolution of wing folding in maniraptoran theropod dinosaurs

    Science.gov (United States)

    Sullivan, Corwin; Hone, David W. E.; Xu, Xing; Zhang, Fucheng

    2010-01-01

    In extant birds, the hand is permanently abducted towards the ulna, and the wrist joint can bend extensively in this direction to fold the wing when not in use. Anatomically, this asymmetric mobility of the wrist results from the wedge-like shape of one carpal bone, the radiale, and from the well-developed convexity of the trochlea at the proximal end of the carpometacarpus. Among the theropod precursors of birds, a strongly convex trochlea is characteristic of Coelurosauria, a clade including the highly derived Maniraptora in addition to tyrannosaurs and compsognathids. The shape of the radiale can be quantified using a ‘radiale angle’ between the proximal and distal articular surfaces. Measurement of the radiale angle and reconstruction of ancestral states using squared-change parsimony shows that the angle was small (15°) in primitive coelurosaurs but considerably larger (25°) in primitive maniraptorans, indicating that the radiale was more wedge-shaped and the carpal joint more asymmetric. The radiale angle progressively increased still further within Maniraptora, with concurrent elongation of the forelimb feathers and the forelimb itself. Carpal asymmetry would have permitted avian-like folding of the forelimb in order to protect the plumage, an early advantage of the flexible, asymmetric wrist inherited by birds. PMID:20200032

  14. The impact of human pressure on the fluctuating asymmetry of Scots pine needles

    Directory of Open Access Journals (Sweden)

    Agnieszka Bęś

    2018-02-01

    Full Text Available This paper presents the results of a study investigating the use of Scots pine needles as bioindicators. The impact of human pressure on Scots pine (Pinus sylvestris L. stands was evaluated based on two indicators (FAM and FAL of the fluctuating asymmetry (FA of needles. The samples of plant material were collected from the Scots pine stands in the immediate vicinity of a road with high traffic intensity, a petroleum refinery and a landfill site for non-hazardous and inert wastes. The analysis revealed significant differences in the FA of needles collected from the stands beside the freeway and the municipal landfill site. The values of FAM and FAL decreased with an increasing distance from the pollution sources. The results of this study indicate that the FA of Scots pine needles could be a reliable indicator for assessing the impact of human pressure on Scots pine stands, complementary to those used traditionally.

  15. Associations among facial masculinity, physical strength, fluctuating asymmetry and attractiveness in young men and women.

    Science.gov (United States)

    Van Dongen, Stefan

    2014-01-01

    Studies of the process of human mate selection and attractiveness have assumed that selection favours morphological features that correlate with (genetic) quality. Degree of masculinity/femininity and fluctuating asymmetry (FA) may signal (genetic) quality, but what information they harboured and how they relate to fitness is still debated. To study strength of associations between facial masculinity/femininity, facial FA, attractiveness and physical strength in humans. Two-hundred young males and females were studied by measuring facial asymmetry and masculinity on the basis of frontal photographs. Attractiveness was determined on the basis of scores given by an anonymous panel, and physical strength using hand grip strength. Patterns differed markedly between males and females and analysis method used (univariate vs multivariate). Overall, no associations between FA and attractiveness, masculinity and physical strength were found. In females, but not males, masculinity and attractiveness correlated negatively and masculinity and physical strength correlated positively. Further research into the differences between males and females in associations between facial morphology, attractiveness and physical strength is clearly needed. The use of a multivariate approach can increase our understanding of which regions of the face harbour specific information of hormone levels and perhaps behavioural traits.

  16. The Effects of Starvation of Honey Bee Larvae on Reproductive Quality and Wing Asymmetry of Honey Bee Drones

    Directory of Open Access Journals (Sweden)

    Szentgyörgyi Hajnalka

    2017-12-01

    Full Text Available Starvation during larval development has a negative effect on adult worker honey bees (Apis mellifera L., but much less is known about the quality of drones starved during their development. We verified how starvation on the second day (early starvation or the sixth day (late starvation of larval development affects body mass, ejaculated semen volume and forewing size, shape, size asymmetry and shape asymmetry in drones after emergence. The larvae were starved for ten hours by being separated from nursing bees with a wire mash for 10 hours either early or late during larval development. Drones starved both early and late were smaller (254.1 ± 1.97 mg and 239.4 ± 2.12 mg, respectively than the control regularly fed individuals (260.9 ± 2.01 mg, and their wing size changed as well (control: 889.76 ± 1.06; early: 880.9 ± 1.17; late: 868.05 ± 1.48. Starvation at a later phase of larval development caused more pronounced effects than at an earlier phase. On the other hand, ejaculated semen volume (control: 0.7 ± 0.043 μl; early: 0.88 ± 0.040 μl; late: 1.08 ± 0.031 μl, wing size asymmetry (control: 0.49 ± 0.025; early: 0.51 ± 0.026; late: 0.52 ± 0.03 and wing shape asymmetry (control: 17.4 ± 0.47 x 10-3; early: 16.9 ± 0.41 x 10-3; late: 17.6 ± 0.43 x 10-3 were not affected by starvation. This suggests that drones attempt to preserve characters which are important for their future reproduction.

  17. Characterization of the up-down asymmetry of density fluctuations induced by a lower modular limiter in Tore Supra

    International Nuclear Information System (INIS)

    Fenzi, C.; Devynck, P.; Garbet, X.; Antar, G.; Capes, H.; Laviron, C.; Truc, A.; Gervais, F.; Hennequin, P.; Quemeneur, A.

    1999-01-01

    In magnetic fusion devices, the effect of plasma facing components on plasma turbulence is a key issue for several reasons. Firstly, the edge turbulence controls the power deposition on plasma facing components. Secondly, the possible influence of the edge parameters on the core fluctuations is a central question, since the core turbulent transport is responsible for the confinement degradation. It is in practice difficult to determine whether the plasma core influences the edge, or the opposite. We show here that spatial edge asymmetries of density fluctuations, and particularly up-down asymmetries, provide a powerful tool to investigate this problem. In TORE SUPRA, previous scaling analyses with various plasma parameters have emphasized that a very clear effect on the asymmetry level appears when the plasma leans on the lower modular limiter located close to the measurement chord. We present here recent measurement results concerning that specific case. They tend to show that the limiter configuration has some effect on the core turbulence. (authors)

  18. Human intelligence, fluctuating asymmetry and the peacock's tail - General intelligence (g) as an honest signal of fitness

    NARCIS (Netherlands)

    Luxen, Marc F.; Buunk, Bram P.; Buunk, Abraham (Bram)

    2006-01-01

    Assuming that general intelligence (g) is an honest signal of fitness, we expected g to be related to developmental quality as indexed by Fluctuating Asymmetry (i.e. non-pathological variation in the size of right and left body features). In a population sample of 44 men and 37 women, we assessed

  19. Fluctuating asymmetry in evaluating the developmental instability of Glossogobius giuris (Hamilton, 1822 from Lake Mainit, Surigao del Norte, Philippines

    Directory of Open Access Journals (Sweden)

    C.C.D.Joseph

    2016-06-01

    Full Text Available This study was conducted to assess the status of Lake Mainit by using fluctuating asymmetry in the populations of Glossogobius giuris. A total of 200 G. giuris was collected with 100 per sex. All the samples were placed in a flat styrofoam for the pinning of its fins to make it wider and to clearly see the samples point of origin for the land-marking process. 10% Formalin was applied in all the fins of the fish samples to make it hardened using a small brush. Twenty (20 landmarks were used to analyze the body shape of the fish. Several studies proved that FA can be used to directly assess water quality and the overall status of the ecosystem. Using thin-plate spline (TPS series, landmark analyses were obtained and subjected to Symmetry and Asymmetry in Geometric Data (SAGE software. Results in Procrustes ANOVA showed that individual symmetry showed a highly significant difference (P = 0.00 as well as Sides (Directional Asymmetry and Interaction (Fluctuating Asymmetry in the study area. All the samples showed FA in both sexes. The results of Principal Component Scores displayed a higher percentage in female (69.2797% than male (63.9214% from Lake Mainit. Variations are almost found in all the body part of the goby in female and male gobies except for anterior insertion of second dorsal fin and superior margin of the preoperculum. Females have a higher fluctuating asymmetry than in males. Females spawn and males protect the eggs from any predators. In this case, females are more susceptible to stress because they have to forage in order to compensate the energy used up during spawning. Males are less susceptible because they usually stay on the nesting ground, and don't have to cover far distances in finding food. This study validates the use of FA in determining the status of the fishes caught connecting to what the status of the environment is based on the result.

  20. Fluctuating asymmetry of meristic traits: an isofemale line analysis in an invasive drosophilid, Zaprionus indianus.

    Science.gov (United States)

    Madi-Ravazzi, Lilian; Segala, Luis Fernando; Debat, Vincent; David, Jean R

    2017-06-01

    Metric (e.g., body size) and meristic (e.g., bristle number) traits are of general use in quantitative genetic studies, and the phenotypic variance is subdivided into a genetic and a non-genetic environmental component. The non-genetic variance may have two origins: a common garden effect between individuals and a developmental instability within the same individual. Developmental instability may be studied by considering the fluctuating asymmetry (FA) between the two sides of the body. The isofemale line technique is a convenient method for investigating the architecture of natural populations but has been rarely implemented for investigating FA. In this paper, we use this experimental design for analyzing four meristic traits in eight populations of the cosmopolitan Zaprionus indianus. A study of the correlation between left and right side of each line revealed that almost 90% of the variability was due to a developmental noise, while a much higher correlation among the means of the lines from the same population was observed. A slight trend toward a directional asymmetry was observed: more thoracic bristles on the left side. Four kinds of indices, scaled or non-scaled to the mean were used for comparing the different traits. Unscaled values (mean absolute values or standard deviation of each line) revealed a linear increase with the means. Interestingly the results of ovariole number were included in the same regression. With the scaled indices (mean absolute divided by each individual value or stadard deviation devided by the mean), the differences among traits were considerably decreased, but still remained significant. The mean FA of the various traits were not correlated, suggesting that each trait harbors its own developmental stability. The CVs of FA were high with a magnitude similar to those of the trait themselves, slightly less than 10%. Finally, even with the isofemale line design, which is a powerful means for unravelling slight genetic variations

  1. A single basis for developmental buffering of Drosophila wing shape.

    Directory of Open Access Journals (Sweden)

    Casper J Breuker

    2006-12-01

    Full Text Available The nature of developmental buffering processes has been debated extensively, based on both theoretical reasoning and empirical studies. In particular, controversy has focused on the question of whether distinct processes are responsible for canalization, the buffering against environmental or genetic variation, and for developmental stability, the buffering against random variation intrinsic in developmental processes. Here, we address this question for the size and shape of Drosophila melanogaster wings in an experimental design with extensively replicated and fully controlled genotypes. The amounts of variation among individuals and of fluctuating asymmetry differ markedly among genotypes, demonstrating a clear genetic basis for size and shape variability. For wing shape, there is a high correlation between the amounts of variation among individuals and fluctuating asymmetry, which indicates a correspondence between the two types of buffering. Likewise, the multivariate patterns of shape variation among individuals and of fluctuating asymmetry show a close association. For wing size, however, the amounts of individual variation and fluctuating asymmetry are not correlated. There was a significant link between the amounts of variation between wing size and shape, more so for fluctuating asymmetry than for variation among individuals. Overall, these experiments indicate a considerable degree of shared control of individual variation and fluctuating asymmetry, although it appears to differ between traits.

  2. Asymmetries in wing inertial and aerodynamic torques contribute to steering in flying insects.

    Science.gov (United States)

    Jankauski, Mark; Daniel, T L; Shen, I Y

    2017-06-08

    Maneuvering in both natural and artificial miniature flying systems is assumed to be dominated by aerodynamic phenomena. To explore this, we develop a flapping wing model integrating aero and inertial dynamics. The model is applied to an elliptical wing similar to the forewing of the Hawkmoth Manduca sexta and realistic kinematics are prescribed. We scrutinize the stroke deviation phase, as it relates to firing latency in airborne insect steering muscles which has been correlated to various aerial maneuvers. We show that the average resultant force production acting on the body largely arises from wing pitch and roll and is insensitive to the phase and amplitude of stroke deviation. Inclusion of stroke deviation can generate significant averaged aerodynamic torques at steady-state and adjustment of its phase can facilitate body attitude control. Moreover, averaged wing angular momentum varies with stroke deviation phase, implying a non-zero impulse during a time-dependent phase shift. Simulations show wing inertial and aerodynamic impulses are of similar magnitude during short transients whereas aerodynamic impulses dominate during longer transients. Additionally, inertial effects become less significant for smaller flying insects. Body yaw rates arising from these impulses are consistent with biologically measured values. Thus, we conclude (1) modest changes in stroke deviation can significantly affect steering and (2) both aerodynamic and inertial torques are critical to maneuverability, the latter of which has not widely been considered. Therefore, the addition of a control actuator modulating stroke deviation may decouple lift/thrust production from steering mechanisms in flapping wing micro aerial vehicles and increase vehicle dexterity through inertial trajectory shaping.

  3. Amniotic fluid deficiency and congenital abnormalities both influence fluctuating asymmetry in developing limbs of human deceased fetuses.

    Directory of Open Access Journals (Sweden)

    Clara Mariquita Antoinette ten Broek

    Full Text Available Fluctuating asymmetry (FA, as an indirect measure of developmental instability (DI, has been intensively studied for associations with stress and fitness. Patterns, however, appear heterogeneous and the underlying causes remain largely unknown. One aspect that has received relatively little attention in the literature is the consequence of direct mechanical effects on asymmetries. The crucial prerequisite for FA to reflect DI is that environmental conditions on both sides should be identical. This condition may be violated during early human development if amniotic fluid volume is deficient, as the resulting mechanical pressures may increase asymmetries. Indeed, we showed that limb bones of deceased human fetuses exhibited increased asymmetry, when there was not sufficient amniotic fluid (and, thus, space in the uterine cavity. As amniotic fluid deficiency is known to cause substantial asymmetries and abnormal limb development, these subtle asymmetries are probably at least in part caused by the mechanical pressures. On the other hand, deficiencies in amniotic fluid volume are known to be associated with other congenital abnormalities that may disturb DI. More specifically, urogenital abnormalities can directly affect/reduce amniotic fluid volume. We disentangled the direct mechanical effects on FA from the indirect effects of urogenital abnormalities, the latter presumably representing DI. We discovered that both factors contributed significantly to the increase in FA. However, the direct mechanical effect of uterine pressure, albeit statistically significant, appeared less important than the effects of urogenital abnormalities, with an effect size only two-third as large. We, thus, conclude that correcting for the relevant direct factors allowed for a representative test of the association between DI and stress, and confirmed that fetuses form a suitable model system to increase our understanding in patterns of FA and symmetry development.

  4. Fluctuating helical asymmetry and morphology of snails (Gastropoda in divergent microhabitats at 'Evolution Canyons I and II,' Israel.

    Directory of Open Access Journals (Sweden)

    Shmuel Raz

    Full Text Available Developmental instability of shelled gastropods is measured as deviations from a perfect equiangular (logarithmic spiral. We studied six species of gastropods at 'Evolution Canyons I and II' in Carmel and the Galilee Mountains, Israel, respectively. The xeric, south-facing, 'African' slopes and the mesic, north-facing, 'European' slopes have dramatically different microclimates and plant communities. Moreover, 'Evolution Canyon II' receives more rainfall than 'Evolution Canyon I.'We examined fluctuating asymmetry, rate of whorl expansion, shell height, and number of rotations of the body suture in six species of terrestrial snails from the two 'Evolution Canyons.' The xeric 'African' slope should be more stressful to land snails than the 'European' slope, and 'Evolution Canyon I' should be more stressful than 'Evolution Canyon II.' Only Eopolita protensa jebusitica showed marginally significant differences in fluctuating helical asymmetry between the two slopes. Contrary to expectations, asymmetry was marginally greater on the 'European' slope. Shells of Levantina spiriplana caesareana at 'Evolution Canyon I,' were smaller and more asymmetric than those at 'Evolution Canyon II.' Moreover, shell height and number of rotations of the suture were greater on the north-facing slopes of both canyons.Our data is consistent with a trade-off between drought resistance and thermoregulation in snails; Levantina was significantly smaller on the 'African' slope, for increasing surface area and thermoregulation, while Eopolita was larger on the 'African' slope, for reducing water evaporation. In addition, 'Evolution Canyon I' was more stressful than Evolution Canyon II' for Levantina.

  5. Fluctuating asymmetry and developmental instability in Protoreaster nodosus (Chocolate Chip Sea Star as a biomarker for environmental stress

    Directory of Open Access Journals (Sweden)

    D. J. V. Trono

    2015-06-01

    Full Text Available Fluctuating asymmetry (FA, pertains to small and random departures from perfect symmetry of an organism's bilateral traits and has been used as a measurement of developmental instability and as a potential indicator of stress in populations. It measures the variations from symmetry of a symmetrical structure whose sides are said to be genetically identical, with similar history of gene activity and experiencing the same environment. Symmetries are potentially the basis for studies on FA. Hence, this study assessed the potential of FA as a reliable developmental instability and environmental stress indicator in five-fold dihedral symmetrical Protoreaster nodosus (Chocolate chip sea fish from three (3 different sites (Linamon, Lanao del Norte; Initao, Misamis Oriental and Jasaan, Misamis Oriental. FA for each population from every site was measured for comparison. In this study, anatomical landmarks were subjected to Procrustes superimposition and Principal Component Analysis (PCA using "Symmetry and Asymmetry in Geometric Data" (SAGE program. Results showed highly significant FA and significant DA for population from Jasaan and Linamon where habitat disturbance due to anthropogenic activities were prevalent. Thus, experienced more stress compared to the other populations, suggesting that significant variation in size or left-right side of each individual could be a product of genotype-environment interaction. Moreover, insignificant FA and high DA was obtained from Initao (protected seascape area which indicated that variation among individual genotypes and asymmetry in phenotypes is mostly induced by genetics under less stressful environment. Significant FA and increase FA present inability of species to buffer stress in its developmental pathways and have implications on species fitness. Hypothesis assumes that fluctuating asymmetry has costs, reflects the quality of individuals and the level of genetic and environmental stress experienced by

  6. Effects of auditory and physical enrichment on 3 measurements of fear and stress (tonic immobility duration, heterophil to lymphocyte ratio, and fluctuating asymmetry) in several breeds of layer chicks.

    Science.gov (United States)

    Dávila, S G; Campo, J L; Gil, M G; Prieto, M T; Torres, O

    2011-11-01

    The purpose of this study was to analyze the effect of auditory enrichment (by means of classical music) or physical enrichment (by means of hanging colored string bunches and barley grains on the floor) on tonic immobility duration, heterophil to lymphocyte ratio, and fluctuating asymmetry (FA) in chicks of several layer breeds. In experiment 1, 192 chicks from 8 Spanish breeds and 1 White Leghorn population were reared in cages with or without music auditory enrichment until 8 wk of age. The effect of music auditory enrichment was significant for heterophil to lymphocyte ratio (P music than in those reared with music, suggesting that auditory enrichment from classical music reduces stress in chicks. There were significant differences in morphological trait measurements (relative asymmetry of wing length, leg width, and combined asymmetry; P music. This result suggests that FA is a good indicator for stress level in chicks, given that it follows the same trend as that found for heterophil to lymphocyte ratio. There was a significant treatment by breed interaction (P stress in layer chicks. In conclusion, auditory enrichment by means of classical music is a reliable method for reducing stress levels in several breeds of layer chicks. However, music auditory enrichment was not effective in reducing fearfulness in any of the layer breeds. Physical enrichment by means of colored plastic string bunches and floor barley grains does not appear to be an effective method for reducing stress and fear in layer chicks.

  7. Fluctuating Asymmetry of Plant Leaves: Batch Processing with LAMINA and Continuous Symmetry Measures

    Directory of Open Access Journals (Sweden)

    John H. Graham

    2015-03-01

    Full Text Available Unlike landmark methods for estimating object asymmetry, continuous symmetry measures (CSM can be used to measure the symmetry distance (ds of inconsistent objects, such as plant leaves. Inconsistent objects have no homologous landmarks, no consistent topology, no quantitative consistency, and sometimes no matching points. When CSM is used in conjugation with LAMINA Leaf Shape Determination software, one can quickly and efficiently process a large number of scanned leaves. LAMINA automatically generates equally-spaced points around the perimeter of each leaf and the resulting x-y coordinates are normalized to average centroid size prior to estimating ds using a fold, average, unfold algorithm. We estimated shape asymmetry of leaves of three species of flowering plants: Ligustrum sinense (Chinese Privet, Rubus cuneifolius (blackberry, and Perilla frutescens (Perilla, as well as individual leaves from a few species of oaks (Quercus and maples (Acer. We found that 100 to 200 equally-spaced points worked well for all three of the main species. Measurement error accounted for a small proportion of the asymmetry variation. Nevertheless, measurement error was great enough to generate some negative size scaling after normalization to average centroid size.

  8. FLUCTUATING ASYMMETRY IN THE OTOLITH WIDTH AND LENGTH OF ADULT TELEOST (Beryx splendens LOWE, 1834 (FAMILY: BERCIDAE COLLECTED FROM THE ARABIAN SEA COASTS OF SULTANATE OF OMAN

    Directory of Open Access Journals (Sweden)

    H.K. Albusaidi

    2010-10-01

    Full Text Available Fluctuating asymmetry was described for the otolith width and length of adult teleost Beryx splendens. The results showed that the level of asymmetry of the otolith width was the highest among the two asymmetry values obtained for the otolith of B. splendens. For the otolith width character, the results showed that the level of asymmetry at its highest value in fish ranging in length between 191–200 mm and in its lowest value in fish ranging in length between 121–180 mm. For the otolith length, the highest value of asymmetry is noticed in fish ranging in length between 231–244 mm and the lowest value in fish within the length of 121–190 mm. The possible cause of the asymmetry in this species has been discussed in relation to different pollutants and their presence in the area. No trend of increase in the asymmetry values with the fish length was noticed for the otolith width, but there is a weak trend of increase with the fish length in case of otolith length character.

  9. Fluctuating and Directional Asymmetry of the Blue Mussel (Mytilus edulis: Improving Methods of Morphological Analysis to Explore Species Performance at the Northern Border of Its Range

    Directory of Open Access Journals (Sweden)

    Dmitry Lajus

    2015-04-01

    Full Text Available In this work we examined morphological variation at different levels to study performance and population structuring of the blue mussel Mytilus edulis. Our objectives were: (i to develop an integrated technique for analyzing morphological variation in blue mussels and, based on this technique; (ii to perform a morphometric description of mussels from the northern part of their range; and (iii to verify the hypothesis that populations at the outer range of their distribution have reduced performance due to harsh climatic conditions. Means, directional asymmetry (i.e., systematic differences between left and right structures, fluctuating asymmetry (random deviations from perfect symmetry, a measure of developmental instability, factorial variation (difference between total variance and variance of fluctuating asymmetry, an indirect index of genotypic variation, and measurement error were examined for 14 bilateral characters of muscle scars on mussel shells. Also, we analyzed one non-bilateral character. For the first time directional asymmetry—approaching 13% of the right:left ratio—was described in blue mussels. Measurement error, often ignored in morphometric studies, contributed 26% of total variance. Accurately addressing these methodical challenges is key to further and improved ecological interpretations. Morphological differences were found between (i samples from estuarine areas in the White and Pechora Seas and (ii samples from Barents Sea areas with oceanic salinity. Samples from the first group exhibited lower fluctuating asymmetry, indicating higher developmental stability likely due to better feeding conditions and lower factorial variation, which may result from lower genotypic variation. Absence of correlation between fluctuating asymmetry and temperature suggests that low temperatures in the northern border of their range do not degrade the performance of adult blue mussels in this region.

  10. Fluctuating asymmetry of shape in rodents from radioactively contaminated environments at Chernobyl

    International Nuclear Information System (INIS)

    Smith, M.H.; Novak, J.M.; Oleksyk, T.K.; Purdue, J.R.; Gashchak, S.

    2002-01-01

    In this study we addressed the question of whether levels of fluctuating symmetry (FA) were elevated in the radioactively contaminated populations compared to reference populations of an abundant rodent living in both environments: the yellow - necked mouse (Apodemus flavicollis). We used six populations of these animals from both inside the radioactively contaminated area close to the failed Chornobyl reactor in Ukraine and in reference areas with no apparent contamination by radionuclides. Twenty-four landmarks on the ventral surface of the rodent's skulls were used to calculate the amounts of FA of shape using Procrustes methods. A higher level of FA was documented for the populations in closest proximity to the failed Chornobyl Nuclear Plant. This index was significantly higher in populations from the most contaminated locations in the Chornobyl Exclusion Zone than in the reference areas. On the other hand, populations from the less contaminated areas inside the Chornobyl Exclusion Zone did not express FA values different from those in the reference populations

  11. Evaluating the developmental instability of Scatophagus argus (Linnaeus, 1766 from Lower Agusan River Basin, Butuan City, Philippines using fluctuating asymmetry

    Directory of Open Access Journals (Sweden)

    J.H. Jumawan

    2016-03-01

    Full Text Available Fluctuating Asymmetry (FA is the most frequently used tool for measuring developmental instability. It is used as a measure of ecological stress and a sign of developmental stability of organisms. The study evaluatedthe use of FA in assessing the condition of Scatophagus argus in lower Agusan river basin. High FA values would indicate exposure to polluted aquatic environment. The study selected S. argus because of its observed susceptibility to aquatic pollution in the area. There were a total of 60 samples collected (30 males and 30 females. Using Thin-Plate Spline (TPS series, landmark analyzes were obtained and subjected to Symmetry and Asymmetry in Geometric Data (SAGE software. Procrustes ANOVA showed high significant differences (P<0.0001 to the three measured factors (individuals, sides and interaction of individuals and sides. Similar findings were observed to both male and females samples suggesting high FA values. The principal component analysis was implemented to determine the affected landmarks. More landmarks were affected in males (11 landmarks than in females (5 landmarks. Deformation grids and histograms were used to display the ordination of affected landmarks. The data would be important to environmental planners in the management of lower Agusan river basin. Scores display a high percentage FA of female (70.94% and male (78.67%. In the female samples, PC 1 (33.26% and PC2 (13.53% were found to have significant variations affecting the rostral tip of premaxilla, posterior extremities, and the lateral profile. In the male samples, PC 1 (35.63% and PC 2 (14.24% have the same affected landmarks as in females but have greater variations. Significant levels of FA in the fish morphology are the result of its adaptive mechanism to cope up with the stressed environment. The dorsal cephalic region and the pectoral fin were the most affected landmarks and may be used to determine the effect of stressors to the fish since these areas

  12. Sexual selection on morphological and physiological traits and fluctuating asymmetry in the black scavenger fly Sepsis cynipsea.

    Science.gov (United States)

    Blanckenhorn, W U; Kraushaar, U R S; Teuschl, Y; Reim, C

    2004-05-01

    Previous univariate studies of the fly Sepsis cynipsea (Diptera: Sepsidae) have demonstrated spatiotemporally variable and consequently overall weak sexual selection favouring large male size, which is nevertheless stronger on average than fecundity selection favouring larger females. To identify specific target(s) of selection on body size and additional traits possibly affecting mating success, two multivariate field studies of sexual selection were conducted. In one study using seasonal replicates from three populations, we assessed 15 morphological traits. No clear targets of sexual selection on male size could be detected, perhaps because spatiotemporal variation in selection was again strong. In particular, there was no (current) selection on male abdomen length or fore coxa length, the only traits for which S. cynipsea males are not smaller than females. Interestingly, copulating males had a consistently shorter fore femur base, a secondary sexual trait, and a wider clasper (hypopygium) gap, an external genital trait. In a second study using daily and seasonal replicates from one population, we included physiological measures of energy reserves (lipids, glucose, glycogen), in addition to hind tibia length and fluctuating asymmetry (FA) of all pairs of legs. This study again confirmed the mating advantage of large males, and additionally suggests independent positive influences of lipids (the long-term energy stores), with effects of glucose and glycogen (the short-term energy stores) tending to be negative. FA of paired traits was not associated with male mating success. Our study suggests that inclusion of physiological measures and genital traits in phenomenological studies of selection, which is rare, would be fruitful in other species.

  13. Effect of post-fire resprouting on leaf fluctuating asymmetry, extrafloral nectar quality, and ant-plant-herbivore interactions

    Science.gov (United States)

    Alves-Silva, Estevão; Del-Claro, Kleber

    2013-06-01

    Fires in the Cerrado savanna are a severe form of disturbance, but some species are capable of resprouting afterwards. It is unknown, however, how and whether post-fire resprouting represents a stressful condition to plants and how their rapid re-growth influences both the production of biochemical compounds, and interactions with mutualistic ants. In this study, we examined the influence of post-fire resprouting on biotic interactions (ant-plant-herbivore relationships) and on plant stress. The study was performed on two groups of the extrafloral nectaried shrub Banisteriopsis campestris (Malpighiaceae); one group was recovering from fire while the other acted as control. With respect to biotic interactions, we examined whether resprouting influenced extrafloral nectar concentration (milligrams per microliter), the abundance of the ant Camponotus crassus and leaf herbivory rates. Plant stress was assessed via fluctuating asymmetry (FA) analysis, which refers to deviations from perfect symmetry in bilaterally symmetrical traits (e.g., leaves) and indicates whether species are under stress. Results revealed that FA, sugar concentration, and ant abundance were 51.7 %, 35.7 % and 21.7 % higher in resprouting plants. Furthermore, C. crassus was significantly associated with low herbivory rates, but only in resprouting plants. This study showed that post-fire resprouting induced high levels of plant stress and influenced extrafloral nectar quality and ant-herbivore relationships in B. campestris. Therefore, despite being a stressful condition to the plant, post-fire resprouting individuals had concentrated extrafloral nectar and sustained more ants, thus strengthening the outcomes of ant-plant mutualism.

  14. Approximate bilateral symmetry in evaporation-induced polycrystalline structures from droplets of wheat grain leakages and fluctuating asymmetry as quality indicator

    Science.gov (United States)

    Kokornaczyk, Maria Olga; Dinelli, Giovanni; Betti, Lucietta

    2013-01-01

    The present paper reports on an observation that dendrite-like polycrystalline structures from evaporating droplets of wheat grain leakages exhibit bilateral symmetry. The exactness of this symmetry, measured by means of fluctuating asymmetry, varies depending on the cultivar and stress factor influence, and seems to correspond to the seed germination rate. In the bodies of plants, animals, and humans, the exactness of bilateral symmetry is known to reflect the environmental conditions of an organism's growth, its health, and its success in sexual selection. In polycrystalline structures, formed under the same conditions, the symmetry exactness depends on the properties of the crystallizing solution such as the composition and viscosity; however, it has never been associated with sample quality. We hypothesize here that, as in living nature, the exactness of approximate bilateral symmetry might be considered a quality indicator also in crystallographic methods applied to food quality analysis.

  15. Describing the body shape variation of spotted barb, Puntius binotatus (Valenciennes 1842 using fluctuating asymmetry from Tubay, Agusan del Norte, Philippines

    Directory of Open Access Journals (Sweden)

    C. J. Presilda

    2016-12-01

    Full Text Available This study aims to assess the condition of the water ecosystem in Tubay, Agusan del Norte by showing the level of FA on the bilateral symmetry of Puntius binotatus with respect to its sex that is known to be abundant in the area. This will show the status of P. binotatus in Tubay, Agusan del Norte that is known for having a mining activity in the area. Yet, there were no reports in the area that concerns with the developmental instability of P. binotatus and other fish inhabiting in the area using FA. Fluctuating Asymmetry (FA defined as a subtle random deviation between the left and right side of symmetrically bilateral organisms that measures the inability of organisms to maintain homeostasis or measures the developmental instability of organisms. A total of 200 individuals (100 male and 100 females were subjected to FA Analysis. Landmark analyses were obtained using Thin - plate Spline (TPS series with 16 landmarks generated for each sample and loaded into Symmetry and Asymmetry in Geometric Data (SAGE software. Procrustes ANOVA shows that individual symmetry has no significant difference. Sides and Interaction showed a high significantly difference (P<0.0001 which suggest being asymmetrical in the bilateral symmetry of P. binotatus population. The result of Principal Component Analysis (PCA shows a level of asymmetry with 77% in female and 73% in the male. FA in female fish can be seen in snout tip, anterior and posterior insertion of the dorsal fin, midpoint, or lateral line, dorsal base of pelvic fin, and dorsal base of pectoral fin. In male samples, affected landmarks can be seen in the anterior and posterior insertion of the dorsal fin, dorsal insertion of caudal fin and dorsal base of the pelvic fin. The level of FA specifies a good indicator of stressors in the environment that causes a decline in reproduction and population.

  16. What’s in a name? Asymmetries in the evaluation of religiously motivated terrorism and right-wing motivated violence in the context of the “refugee crisis”

    Directory of Open Access Journals (Sweden)

    Noreen van Elk

    2016-09-01

    Full Text Available In the course of 2015, Germany was confronted with ever increasing immigration flows which resulted in the so-called “refugee crisis”. This sudden political and societal challenge brought about feelings of fear, anxiety and insecurity in many people. As a result, the right-wing Populist Party AFD and the populist movement PEGIDA steadily gained more support. Furthermore, the number of right-wing motivated crimes reached a total of 13 846 by the end of December 2015, of which 4183 were declared as motivated by “anti-migrant” or xenophobic sentiments. However, it appears as if the German government has difficulties reacting appropriately to those developments. This paper argues that the asymmetry between the moral and political evaluation of transnational religiously motivated terrorist violence and domestic right-wing extremist violence is untenable. Consequently, the emphasis on safeguarding national security against the risk of this kind of terrorist violence denies the importance of dealing with the right-wing risk “from within”. It is argued, that the increasing right-wing motivated violence shares certain dynamics with religiously motivated terrorism, even though both phenomena differ in fatality. The choice to call one form of violence terrorism and another form, in this case right-wing extremist violence, is not considered as terrorism, is not as neutral as is often presumed and is certainly not exclusively attributable to the differing character or fatality of the violence. It will be shown that instead, it reveals a lot about certain prejudices, a priori assumptions about the nature of terrorism, prevailing resentment and political interest.

  17. Fluctuating asymmetry in Bobwhite quail chicks (Colinus virginianus) does not follow a predictable dose-response relationship following maternal exposure to four different herbicides

    International Nuclear Information System (INIS)

    Knopper, Loren D.; Mineau, Pierre

    2004-01-01

    Most biomonitoring studies that have investigated the relationship between fluctuating asymmetry (FA) and anthropogenic stressors have measured organisms from polluted ecosystems and compared them to organisms at reference sites. What has received little attention is whether FA follows a dose-response relationship with stress, a key criterion of a useful biomarker. Using chicks from currently mandated avian reproductive tests we tested whether a composite index of FA (FA C ), was related to the dose or duration of exposure of their parents to one of four different herbicides, and if FA C was indeed a more sensitive marker of stress than standard reproductive endpoints measured from this test. We found no consistent relationship between FA C and dose or duration of herbicide exposure in any of the four studies. Exposure to one of the four pesticides did result in significant reproductive toxicity but this was not accompanied or foreshadowed by higher levels of FA C . Our results do not support the hypothesis that FA is a reliable general biomarker of pesticide exposure

  18. Consistent Positive Co-Variation between Fluctuating Asymmetry and Sexual Trait Size: A Challenge to the Developmental Instability-Sexual Selection Hypothesis

    Directory of Open Access Journals (Sweden)

    Michal Polak

    2015-06-01

    Full Text Available The developmental instability (DI-sexual selection hypothesis proposes that large size and symmetry in secondary sexual traits are favored by sexual selection because they reveal genetic quality. A critical prediction of this hypothesis is that there should exist negative correlations between trait fluctuating asymmetry (FA and size of condition dependent sexual traits; condition dependent traits should reveal an organism’s overall health and vigor, and be influenced by a multitude of genetic loci. Here, we tested for the predicted negative FA-size correlations in the male sex comb of Drosophila bipectinata. Among field-caught males from five widely separated geographic localities, FA-size correlations were consistently positive, despite evidence that sex comb size is condition dependent. After controlling for trait size, FA was significantly negatively correlated with body size within several populations, indicating that developmental instability in the comb may reveal individual genetic quality. We suggest the possibility that condition dependent traits in some cases tap into independent units of the genome (a restricted set of genes, rather than signaling overall genetic properties of the organism. There were pronounced among-population differences in both comb FA and size, and these traits were positively correlated across populations, recapitulating the within-population patterns. We conclude that the results are inconsistent with the DI-sexual selection hypothesis, and discuss potential reasons for positive FA-size co-variation in sexual traits.

  19. Fluctuating asymmetry and genetic variability in the roe deer (Capreolus capreolus): a test of the developmental stability hypothesis in mammals using neutral molecular markers.

    Science.gov (United States)

    Zachos, F E; Hartl, G B; Suchentrunk, F

    2007-06-01

    Fluctuating asymmetry (FA), used as an indicator of developmental stability, has long been hypothesized to be negatively correlated with genetic variability as a consequence of more variable organisms being better suited to buffer developmental pathways against environmental stress. However, it is still a matter of debate if this is due to metabolic properties of enzymes encoded by certain key loci or rather to overall genomic heterozygosity. Previous analyses suggest that there might be a general difference between homeo- and poikilotherms in that only the latter tend to exhibit the negative correlation predicted by theory. In the present study, we addressed these questions by analysing roe deer (Capreolus capreolus) from five German populations with regard to FA in metric and non-metric skull and mandible traits as well as variability at eight microsatellite loci. Genetic variability was quantified by heterozygosity and mean d2 parameters, and although the latter did not show any relationship with FA, we found for the first time a statistically significant negative correlation of microsatellite heterozygosity and non-metric FA among populations. Because microsatellites are non-coding markers, this may be interpreted as evidence for the role of overall genomic heterozygosity in determining developmental stability. To test if the threshold character of non-metric traits is responsible for the metric vs non-metric difference we also carried out calculations where we treated our metric traits as threshold values. This, however, did not yield significant correlations between FA and genetic variability either.

  20. Tri-Trophic Impacts of Bt-Transgenic Maize on Parasitoid Size and Fluctuating Asymmetry in Native vs. Novel Host-Parasitoid Interactions in East Africa

    Directory of Open Access Journals (Sweden)

    Dennis O. Ndolo

    2018-03-01

    Full Text Available Environmental stress can affect trait size and cause an increase in the fluctuating asymmetry (FA of bilateral morphological traits in many animals. For insect parasitoids, feeding of hosts on transgenic maize, expressing a Bacillus thuringiensis toxin gene is a potential environmental stressor. We compared the size of antennae, forewings, and tibia, as well as their FA values, in two parasitoids developed on two East African host species feeding on non-transgenic vs. transgenic maize. The two lepidopteran stem-borer hosts were the native Sesamia calamistis Hampson (Lepidoptera: Noctuidae and a recent invader, Chilo partellus Swinhoe (Lepidoptera: Crambidae. The two braconid parasitoids were the native, gregarious larval endoparasitoid Cotesia sesamiae and the recently introduced Cotesia flavipes. Both parasitoids attacked both hosts, creating evolutionarily old vs. novel interactions. Transient feeding of hosts on transgenic maize had various effects on FA, depending on trait as well as the host and parasitoid species. These effects were usually stronger in evolutionarily novel host–parasitoid associations than in the older, native ones. These parameters have capacity to more sensitively indicate the effects of potential stressors and merit further consideration.

  1. Fluctuating asymmetry rather than oxidative stress in Bufo raddei can be an accurate indicator of environmental pollution induced by heavy metals.

    Science.gov (United States)

    Guo, Rui; Zhang, Wenya; Ai, Shiwei; Ren, Liang; Zhang, Yingmei

    2017-06-01

    Oxidative stress (OS) and fluctuating asymmetry (FA) as risk markers for environmental stress are widely used to predict changes in the health and fitness of many animals exposed to pollutants. However, from the perspective of protecting declining amphibians, it remains to be verified which one would be a reliable indicator for amphibians exposed to long-term heavy metal pollution under natural conditions. In this study, the OS and FA of Bufo raddei exposed to natural heavy metal pollution were analyzed to determine which marker is more accurate for indicating heavy metal-induced stress. Three years of data were collected during the breeding season of B. raddei from Baiyin (BY), which has been mainly contaminated with Cu, Zn, Pb, and Cd compounds for a long period, and from Liujiaxia (LJX), which is a relatively unpolluted area. Unexpectedly, although significant accumulation of the four heavy metals was found in the kidney and liver of B. raddei from BY, the levels of superoxide dismutase, glutathione peroxidase, and malondialdehyde in these two organs were found to be irregular, with low repeatability in both BY and LJX. However, significant differences in the levels of FA were observed in B. raddei populations from these two areas over the past 3 years (P environmental stress on anuran amphibians.

  2. The relationship between asymmetry, size and unusual venation in honey bees (Apis mellifera).

    Science.gov (United States)

    Łopuch, S; Tofilski, A

    2016-06-01

    Despite the fact that symmetry is common in nature, it is rarely perfect. Because there is a wide range of phenotypes which differs from the average one, the asymmetry should increase along with deviation. Therefore, the aim of this study was to assess the level of asymmetry in normal individuals as well as in phenodeviants categorized as minor or major based on abnormalities in forewing venation in honey bees. Shape fluctuating asymmetry (FA) was lower in normal individuals and minor phenodeviants compared with major phenodeviants, whereas the former two categories were comparable in drones. In workers and queens, there were not significant differences in FA shape between categories. FA size was significantly lower in normal individuals compared with major phenodeviant drones and higher compared with minor phenodeviant workers. In queens, there were no significant differences between categories. The correlation between FA shape and FA size was significantly positive in drones, and insignificant in workers and queens. Moreover, a considerable level of directional asymmetry was found as the right wing was constantly bigger than the left one. Surprisingly, normal individuals were significantly smaller than minor phenodeviants in queens and drones, and they were comparable with major phenodeviants in all castes. The correlation between wing size and wing asymmetry was negative, indicating that smaller individuals were more asymmetrical. The high proportion of phenodeviants in drones compared with workers and queens confirmed their large variability. Thus, the results of the present study showed that minor phenodeviants were not always intermediate as might have been expected.

  3. Repeated exposure to enhanced UV-B radiation in successive generations increases developmental instability (leaf fluctuating asymmetry) in a desert annual

    International Nuclear Information System (INIS)

    Midgley, G.F.; Wand, S.J.E.; Musil, C.F.

    1998-01-01

    Populations of the desert annual Dimorphotheca sinuata, derived from a common seed stock, were exposed concurrently over four successive generations to either ambient (representing no stratospheric ozone depletion) or elevated (representing 20% stratospheric ozone depletion) UV-B levels during their complete life cycle. Leaf fluctuating asymmetry (FA) was measured in populations of plants grown from seeds of selected generations which had experienced different UV-B exposure histories, and from seeds collected from a wild population of this species which grows in a naturally enhanced UV-B environment. These measured plants had been grown in a greenhouse under essentially UV-B-free conditions. Leaf FA was significantly increased by greater numbers of enhanced UV-B exposures in the parentage of the seed. There was a linear to exponential dose–response relationship between number of UV-B exposure iterations in seed parentage and leaf FA, suggesting that damage to DNA caused by UV-B exposure during plant development may not be fully repaired, and thus be inherited by offspring and accumulated over successive generations in this species. Leaf FA of plants grown from seed from the wild population was not significantly greater than that of control plants whose parentage experienced only ambient UV-B exposures, although this negative result may have been due to low sampling intensity and measurement resolution, and the relatively low UV-B enhancement experienced by the wild population. We conclude that leaf FA may constitute a relatively sensitive yet inexpensive means of quantifying UV-B damage to plants. (author)

  4. Analysis of density fluctuations in the Tore Supra tokamak. Up-down asymmetries and limiter effect on plasma turbulence; Etude des fluctuations de density dans les plasmas du tokamak Tore Supra. Asymetries haut-bas et effet du limiteur sur la turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Fenzi, Ch

    1999-10-29

    In magnetic fusion devices, the optimisation of the power deposition profile on plasma facing components crucially depends on the heat diffusivity across the magnetic field fines, which is determined by the plasma edge turbulence. In this regard, spatial asymmetries of plasma edge turbulence are of great interest. In this work, we interest in up-down asymmetries of density fluctuations which are usually observed in Tore Supra, using a coherent light scattering experiment. It is shown that these asymmetries are correlated to the plasma edge geometrical configuration (plasma facing components, limiters). In fact, the plasma-limiter interaction induces locally in the plasma edge and the SOL (r/a > 0.9) an additional turbulence with short correlation length along the magnetic field fines, which spreads in the plasma core (0.9 {>=} r/a {>=} 0.5). The resultant up-down asymmetry weakly depends on density, increases with the edge safety factor, and inverts when the plasma current direction is reversed. Such up-down asymmetry observations bring strong impact on edge turbulence and transport models, which usually predict a ballooning of the turbulence in the high-field side but not an up-down asymmetry. A possible model is proposed here, based on the Kelvin Helmholtz instability. (author)

  5. A comparative fluctuating asymmetry study between two walnut (Juglans regia L.) populations may contribute as an early signal for bio-monitoring

    NARCIS (Netherlands)

    Kourmpetis, Y.I.A.; Aravanopoulos, F.A.

    2010-01-01

    Developmental stability, the ability of an individual to eliminate environmental disturbances while expressing a heritable phenotypic trait, was compared in two walnut (Juglans regia L.) populations, a natural and an artificial. Bilateral leaf morphometrics were used to estimate fluctuating

  6. Nasopupillary asymmetry.

    Science.gov (United States)

    Arenas, Eduardo; Muñoz, Diana; Matheus, Evelyn; Morales, Diana

    2014-01-01

    To establish the prevalence of nasopupillary asymmetry (difference in nasopupillary distances) in the population and its relation with the interpupillary distance. A retrospective descriptive study was conducted by reviewing of 1262 medical records. The values of nasopupillary asymmetry and the interpupillary distance were obtained. A statistical analysis was made and the correlation between these variables was established. Seventy-nine percent of the population presented some degree of nasopupillary asymmetry. The interpupillary distance had a very low correlation with the nasopupillary asymmetry (r = 0.074, P = 0.0). It is advisable to use the nasopupillary distance of each eye as a standard measurement.

  7. Dermatoglyphic asymmetry and hair whorl patterns in schizophrenic and bipolar patients.

    Science.gov (United States)

    Yousefi-Nooraie, Reza; Mortaz-Hedjri, Soroush

    2008-01-15

    Dermatoglyphic quantitative counts, asymmetry between two hands, and hair whorls were assessed in schizophrenic, bipolar and normal samples. Higher dermatoglyphic directional asymmetry and lower fluctuating asymmetry in bipolar patients support their hypernormal asymmetries. An inverse association between hair whorl location and dermatoglyphic asymmetry in schizophrenia may show a higher probability of lateralization problems.

  8. Inclusive asymmetries

    International Nuclear Information System (INIS)

    Peterson, E.A.

    1977-01-01

    The polarized proton beam was used to measure left-right asymmetries for the reactions p + p → p, K +- , π +- + anything and also some information on the reaction p + n → p, K +- , π + + anything are presented. The incident momentum is 11.8 GeV/c. The data are preliminary. Six references

  9. Osteology and myology of the wing of the Emu (Dromaius novaehollandiae), and its bearing on the evolution of vestigial structures.

    Science.gov (United States)

    Maxwell, Erin E; Larsson, Hans C E

    2007-05-01

    Emus have reduced their wing skeleton to only a single functional digit, but the myological changes associated with this reduction have never been properly described. Moreover, the intraspecific variability associated with these changes has not previously been examined, dissections having been restricted in the past to only one or two individuals. In this paper, the myology and osteology of the Emu wing is described for a sample of five female birds. The Emu showed a marked reduction in the number of muscles in the wing, even compared with other ratites. Many wing muscles showed diversity in structure, origin and insertion sites, number of heads, as well as presence-absence variation. This variability dramatically exceeds that found in flying birds. Evolutionary theory predicts that relaxed selection on vestigial organs should allow more variation to persist in the population, and corresponds to what is observed here. A large amount of fluctuating asymmetry was also detected, indicating reduced canalization of the wing during development. (c) 2007 Wiley-Liss, Inc.

  10. THE ONTOGENY OF ASYMMETRY IN EARWIG FORCEPS.

    Science.gov (United States)

    Tomkins, Joseph L

    1999-02-01

    Fluctuating asymmetry may play an important role in the evolution of naturally selected and secondary sexual traits. However, very little is known about how asymmetries arise or how organisms maintain symmetry during development. Here I propose three mutually exclusive patterns for the development of asymmetries through consecutive growth stages: (1) compensatory growth, in which growth of the shorter side is greatest at the following growth stage; (2) persistent growth, in which growth of the longer side is greatest at the following growth stage; and (3) uncorrelated growth in which growth of the following stage is unrelated to the asymmetry at the previous one. I followed the growth in the forceps of male earwigs through four successive instars. Dyar's rule was used as a null model of insect growth. In the molt from the second to third instar, asymmetries increased through uncorrelated growth and with the magnitude but not the sign expected from Dyar's rule. However, following this, at the molts between instars 3-4 and 4-5, compensatory growth maintained asymmetries at a lower level than expected from Dyar's rule. Although there was no reduction in the absolute magnitude of asymmetry, relative asymmetry did decline. The net growth of forceps length did not follow Dyar's rule. The interpretation of patterns of growth were more sensitive and informative than the interpretation of the relations between asymmetries at consecutive instars. © 1999 The Society for the Study of Evolution.

  11. Puzzling asymmetries

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    In a recently published paper, the LHCb Collaboration has reported on a possible deviation from the Standard Model. Theorists are now working to calculate precisely this effect and to evaluate the implications that such unexpected result could have on the established theory.   The Standard Model is able to predict the decay rates of particles with high precision. In most cases, experimentalists confirm the value predicted by theory and the figure is added to the official publications. However, this time, things seem to have taken a different route. Studying data collected in 2011, the LHCb Collaboration found that in a specific decay – a B particle transforming into a K particle plus two charged muons (B -> Kμ-μ+) – the branching ratio of the neutral B in the corresponding decay (i.e. B0 -> K0μ-μ+) is different from that of the positively charged B (i.e. B+ -> K+μ-μ+). Such an “isospin asymmetry&rdquo...

  12. Aerodynamic effects of flexibility in flapping wings

    Science.gov (United States)

    Zhao, Liang; Huang, Qingfeng; Deng, Xinyan; Sane, Sanjay P.

    2010-01-01

    Recent work on the aerodynamics of flapping flight reveals fundamental differences in the mechanisms of aerodynamic force generation between fixed and flapping wings. When fixed wings translate at high angles of attack, they periodically generate and shed leading and trailing edge vortices as reflected in their fluctuating aerodynamic force traces and associated flow visualization. In contrast, wings flapping at high angles of attack generate stable leading edge vorticity, which persists throughout the duration of the stroke and enhances mean aerodynamic forces. Here, we show that aerodynamic forces can be controlled by altering the trailing edge flexibility of a flapping wing. We used a dynamically scaled mechanical model of flapping flight (Re ≈ 2000) to measure the aerodynamic forces on flapping wings of variable flexural stiffness (EI). For low to medium angles of attack, as flexibility of the wing increases, its ability to generate aerodynamic forces decreases monotonically but its lift-to-drag ratios remain approximately constant. The instantaneous force traces reveal no major differences in the underlying modes of force generation for flexible and rigid wings, but the magnitude of force, the angle of net force vector and centre of pressure all vary systematically with wing flexibility. Even a rudimentary framework of wing veins is sufficient to restore the ability of flexible wings to generate forces at near-rigid values. Thus, the magnitude of force generation can be controlled by modulating the trailing edge flexibility and thereby controlling the magnitude of the leading edge vorticity. To characterize this, we have generated a detailed database of aerodynamic forces as a function of several variables including material properties, kinematics, aerodynamic forces and centre of pressure, which can also be used to help validate computational models of aeroelastic flapping wings. These experiments will also be useful for wing design for small robotic

  13. Aerodynamic effects of flexibility in flapping wings.

    Science.gov (United States)

    Zhao, Liang; Huang, Qingfeng; Deng, Xinyan; Sane, Sanjay P

    2010-03-06

    Recent work on the aerodynamics of flapping flight reveals fundamental differences in the mechanisms of aerodynamic force generation between fixed and flapping wings. When fixed wings translate at high angles of attack, they periodically generate and shed leading and trailing edge vortices as reflected in their fluctuating aerodynamic force traces and associated flow visualization. In contrast, wings flapping at high angles of attack generate stable leading edge vorticity, which persists throughout the duration of the stroke and enhances mean aerodynamic forces. Here, we show that aerodynamic forces can be controlled by altering the trailing edge flexibility of a flapping wing. We used a dynamically scaled mechanical model of flapping flight (Re approximately 2000) to measure the aerodynamic forces on flapping wings of variable flexural stiffness (EI). For low to medium angles of attack, as flexibility of the wing increases, its ability to generate aerodynamic forces decreases monotonically but its lift-to-drag ratios remain approximately constant. The instantaneous force traces reveal no major differences in the underlying modes of force generation for flexible and rigid wings, but the magnitude of force, the angle of net force vector and centre of pressure all vary systematically with wing flexibility. Even a rudimentary framework of wing veins is sufficient to restore the ability of flexible wings to generate forces at near-rigid values. Thus, the magnitude of force generation can be controlled by modulating the trailing edge flexibility and thereby controlling the magnitude of the leading edge vorticity. To characterize this, we have generated a detailed database of aerodynamic forces as a function of several variables including material properties, kinematics, aerodynamic forces and centre of pressure, which can also be used to help validate computational models of aeroelastic flapping wings. These experiments will also be useful for wing design for small

  14. Hα LINE PROFILE ASYMMETRIES AND THE CHROMOSPHERIC FLARE VELOCITY FIELD

    Energy Technology Data Exchange (ETDEWEB)

    Kuridze, D.; Mathioudakis, M.; Kennedy, M.; Keenan, F. P. [Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast BT7 1NN (United Kingdom); Simões, P. J. A.; Voort, L. Rouppe van der; Fletcher, L. [SUPA School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Carlsson, M.; Jafarzadeh, S. [Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, NO-0315 Oslo (Norway); Allred, J. C.; Kowalski, A. F. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Graham, D. [INAF-Ossevatorio Astrofisico di Arcetri, I-50125 Firenze (Italy)

    2015-11-10

    The asymmetries observed in the line profiles of solar flares can provide important diagnostics of the properties and dynamics of the flaring atmosphere. In this paper the evolution of the Hα and Ca ii λ8542 lines are studied using high spatial, temporal, and spectral resolution ground-based observations of an M1.1 flare obtained with the Swedish 1 m Solar Telescope. The temporal evolution of the Hα line profiles from the flare kernel shows excess emission in the red wing (red asymmetry) before flare maximum and excess in the blue wing (blue asymmetry) after maximum. However, the Ca ii λ8542 line does not follow the same pattern, showing only a weak red asymmetry during the flare. RADYN simulations are used to synthesize spectral line profiles for the flaring atmosphere, and good agreement is found with the observations. We show that the red asymmetry observed in Hα is not necessarily associated with plasma downflows, and the blue asymmetry may not be related to plasma upflows. Indeed, we conclude that the steep velocity gradients in the flaring chromosphere modify the wavelength of the central reversal in the Hα line profile. The shift in the wavelength of maximum opacity to shorter and longer wavelengths generates the red and blue asymmetries, respectively.

  15. Broiler walking ability and toe asymmetry under harsh rearing conditions

    Directory of Open Access Journals (Sweden)

    MS Baracho

    2012-09-01

    Full Text Available Morphological asymmetry has been described as a potential broiler welfare indicator, for interpreting the birds' ability to cope with the challenges that may affect its growth. The objective of this study was to evaluate the use of morphological asymmetry data to estimate broiler walking ability and welfare.dBroilers werefed diets supplemented or not with vitamin D. Toes were measured when birds were 42 and 49 days old using digital caliper.the left and right sides of the following four bilateral traits (tarsometatarsus length, outer toe length, mid toe length, and back toe length were measured twice on intact alive birds by two different researcherh. Data from right and left sides were compared in the two treatments using the Student t-test, and Pearson's correlation was used to analyze the total asymmetry found as a result of the total sum of the differences in the measurements. Asymmetry data were comparedwith the total numberof leg lesions. Mid toe and tarsometatarsus asymmetry resultswere considered as actual fluctuating asymmetry, and presented normal distribution (Test of Kolmogorov-Smirnov, p >0.05. However, back toe and outer toe measurements were not normally distributed, as determined by the test of Kolmogorov-Smirnov (p <0.05, indicating anti-asymmetry; when comparing right with left limb,results were significantly different fron zero (t-Student, p <0.05 indicating directional fluctuating asymmetry.The welfare of broilers withwalking difficulty due to the presence of severe asymmetry in limbs is poor.

  16. Asymmetry dependence of the nuclear caloric curve

    International Nuclear Information System (INIS)

    McIntosh, A.B.; Bonasera, A.; Cammarata, P.; Hagel, K.; Heilborn, L.; Kohley, Z.; Mabiala, J.; May, L.W.; Marini, P.; Raphelt, A.; Souliotis, G.A.; Wuenschel, S.; Zarrella, A.; Yennello, S.J.

    2013-01-01

    A basic feature of the nuclear equation of state is not yet understood: the dependence of the nuclear caloric curve on the neutron–proton asymmetry. Predictions of theoretical models differ on the magnitude and even the sign of this dependence. In this work, the nuclear caloric curve is examined for fully reconstructed quasi-projectiles around mass A=50. The caloric curve extracted with the momentum quadrupole fluctuation thermometer shows that the temperature varies linearly with quasi-projectile asymmetry (N−Z)/A . An increase in asymmetry of 0.15 units corresponds to a decrease in temperature on the order of 1 MeV. These results also highlight the importance of a full quasi-projectile reconstruction in the study of thermodynamic properties of hot nuclei

  17. Forward-backward asymmetries with quark jets

    International Nuclear Information System (INIS)

    Davier, M.; Richard, F.

    1979-01-01

    One of the most challenging experimental problems at LEP is the measurement of the weak couplings of the quarks. As is well known for lepton pair production, forward-backward asymmetries are very sensitive to these couplings. The problem of determining the jet flavour in order to measure such asymmetries is considered. Two methods are discussed: (i) measuring the charge of the jet which should reflect the quark charge with unfortunately large fluctuations. This could be a way to isolate Q=2/3 quarks (top) and measure the asymmetry for these tanti t pairs; and (ii) using leading particles to assign the jet flavour. It is known that, when E/Esub(beam) =x→1, the probability that the leading meson carries the initial quark with approach unity. The second method is discussed in detail. (Auth.)

  18. Quantum fluctuations within the fragmentation theory

    International Nuclear Information System (INIS)

    Maruhn, J.A.; Hahn, J.; Lustig, H.J.; Zeigenhain, K.H.; Greiner, W.

    1980-01-01

    The measured spread of the fragment mass distributions in heavy ion collisions may be due to two quite different physical mechanisms: the quantum-mechanical uncertainty associated with collective motion in the mass asymmetry degree of freedom, and the spread caused by thermal excitation of the nuclear system. The fluctuations in physical observables induced in these ways are referred to as quantum fluctuations and statistical fluctuations. In this lecture quantum fluctuations are studied within the fragmentation theory. Mass distributions for spontaneous fission and low energy heavy ion collisions are investigated. (author)

  19. Time-reversal asymmetry in financial systems

    Science.gov (United States)

    Jiang, X. F.; Chen, T. T.; Zheng, B.

    2013-11-01

    We investigate the large-fluctuation dynamics in financial markets, based on the minute-to-minute and daily data of the Chinese Indices and the German DAX. The dynamic relaxation both before and after the large fluctuations is characterized by a power law, and the exponents p± usually vary with the strength of the large fluctuations. The large-fluctuation dynamics is time-reversal symmetric at the time scale in minutes, while asymmetric at the daily time scale. Careful analysis reveals that the time-reversal asymmetry is mainly induced by external forces. It is also the external forces which drive the financial system to a non-stationary state. Different characteristics of the Chinese and German stock markets are uncovered.

  20. Asymmetries at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Bartos, Pavol [Comenius U.

    2014-10-28

    In this report, we summarize the latest results of the top-quark pair production asymmetry and present the new result of bottom-quark pair production asymmetry. By looking at the results obtained by the CDF experiment, one can see a discrepancy in both $t\\bar{t}$ inclusive and lepton-based measurements. The D0 results of the $t\\bar{t}$ production asymmetry are compatible with the standard-model predictions as well as with the CDF results. The CDF measurement of $b\\bar{b}$ production asymmetry presents consistency with both zero and with the standard-model predictions.

  1. The Effect of Height, Wing Length, and Wing Symmetry on Tabebuia rosea Seed Dispersal

    Directory of Open Access Journals (Sweden)

    Yasmeen Moussa

    2014-12-01

    Full Text Available The relationship between the vertical drop height and the horizontal distance traveled (dispersal ratio was investigated for a sample of fifty Tabebuia rosea seeds by dropping the seeds from five heights ranging from 1.00 to 2.00 meters. The dispersal ratio was found to be a constant 0.16 m/m for these heights. The effects of total seed length and asymmetry of seed wings on dispersal ratio were also measured using separate samples of fifty Tabebuia rosea seeds. It was found that neither seed length nor asymmetry had a significant effect on the dispersal ratio.

  2. Streamwise Fluctuations of Vortex Breakdown at High Reynolds Numbers

    National Research Council Canada - National Science Library

    Connelly, Jonathan S

    2006-01-01

    This thesis deals with the characterization of the dependence on the flow geometry of the stream wise fluctuations of the stagnation point of vortex breakdown in axisymmetric tubes and over delta wing aircraft...

  3. Hovering hummingbird wing aerodynamics during the annual cycle. I. Complete wing.

    Science.gov (United States)

    Achache, Yonathan; Sapir, Nir; Elimelech, Yossef

    2017-08-01

    The diverse hummingbird family (Trochilidae) has unique adaptations for nectarivory, among which is the ability to sustain hover-feeding. As hummingbirds mainly feed while hovering, it is crucial to maintain this ability throughout the annual cycle-especially during flight-feather moult, in which wing area is reduced. To quantify the aerodynamic characteristics and flow mechanisms of a hummingbird wing throughout the annual cycle, time-accurate aerodynamic loads and flow field measurements were correlated over a dynamically scaled wing model of Anna's hummingbird ( Calypte anna ). We present measurements recorded over a model of a complete wing to evaluate the baseline aerodynamic characteristics and flow mechanisms. We found that the vorticity concentration that had developed from the wing's leading-edge differs from the attached vorticity structure that was typically found over insects' wings; firstly, it is more elongated along the wing chord, and secondly, it encounters high levels of fluctuations rather than a steady vortex. Lift characteristics resemble those of insects; however, a 20% increase in the lift-to-torque ratio was obtained for the hummingbird wing model. Time-accurate aerodynamic loads were also used to evaluate the time-evolution of the specific power required from the flight muscles, and the overall wingbeat power requirements nicely matched previous studies.

  4. Dissymmetry and Asymmetry

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 8. Dissymmetry and Asymmetry - A Hopeless Conflict in Chemical Literature. Chandan Saha Suchandra Chakraborty. General Article Volume 17 Issue 8 August 2012 pp 768-778 ...

  5. Quantum fluctuations

    International Nuclear Information System (INIS)

    Reynaud, S.; Giacobino, S.; Zinn-Justin, J.

    1997-01-01

    This course is dedicated to present in a pedagogical manner the recent developments in peculiar fields concerned by quantum fluctuations: quantum noise in optics, light propagation through dielectric media, sub-Poissonian light generated by lasers and masers, quantum non-demolition measurements, quantum electrodynamics applied to cavities and electrical circuits involving superconducting tunnel junctions. (A.C.)

  6. Quantitative-genetic analysis of wing form and bilateral asymmetry ...

    Indian Academy of Sciences (India)

    Author Affiliations. Pedro Fernández Iriarte1 Walkiria Céspedes1 Mauro Santos1. Grup de Biologia Evolutiva (GBE), Departament de Genètica i de Microbiologia, Universitat Autònoma de Barcelona, 08193 Bellaterra (Barcelona), Spain ...

  7. Quantitative-genetic analysis of wing form and bilateral asymmetry ...

    Indian Academy of Sciences (India)

    Unknown

    The constructive criticisms provided by Vincent Debat and an anonymous referee on earlier drafts were very helpful to sig- nificantly improve the manuscript. P. F. I. is supported by a postdoctoral fellowship (SB2000-0370) from the Secretaría de. Estado de Educación y Universidades del Ministerio de Educa- ción, Cultura y ...

  8. Morphing Wing: Experimental Boundary Layer Transition Determination and Wing Vibrations Measurements and Analysis =

    Science.gov (United States)

    Tondji Chendjou, Yvan Wilfried

    This Master's thesis is written within the framework of the multidisciplinary international research project CRIAQ MDO-505. This global project consists of the design, manufacture and testing of a morphing wing box capable of changing the shape of the flexible upper skin of a wing using an actuator system installed inside the wing. This changing of the shape generates a delay in the occurrence of the laminar to turbulent transition area, which results in an improvement of the aerodynamic performances of the morphed wing. This thesis is focused on the technologies used to gather the pressure data during the wind tunnel tests, as well as on the post processing methodologies used to characterize the wing airflow. The vibration measurements of the wing and their real-time graphical representation are also presented. The vibration data acquisition system is detailed, and the vibration data analysis confirms the predictions of the flutter analysis performed on the wing prior to wind tunnel testing at the IAR-NRC. The pressure data was collected using 32 highly-sensitive piezoelectric sensors for sensing the pressure fluctuations up to 10 KHz. These sensors were installed along two wing chords, and were further connected to a National Instrument PXI real-time acquisition system. The acquired pressure data was high-pass filtered, analyzed and visualized using Fast Fourier Transform (FFT) and Standard Deviation (SD) approaches to quantify the pressure fluctuations in the wing airflow, as these allow the detection of the laminar to turbulent transition area. Around 30% of the cases tested in the IAR-NRC wind tunnel were optimized for drag reduction by the morphing wing procedure. The obtained pressure measurements results were compared with results obtained by infrared thermography visualization, and were used to validate the numerical simulations. Two analog accelerometers able to sense dynamic accelerations up to +/-16g were installed in both the wing and the aileron boxes

  9. Dynamic Model and Analysis of Asymmetric Telescopic Wing for Morphing Aircraft

    Directory of Open Access Journals (Sweden)

    Chen Lili

    2016-01-01

    Full Text Available Morphing aircraft has been the research hot topics of new concept aircrafts in aerospace engineering. Telescopic wing is an important morphing technology for morphing aircraft. This paper describes the dynamic equations and kinematic equations based on theorem of momentum and theorem of moment of momentum, which are available for all morphing aircrafts. Meanwhile,as simplified , dynamic equations for rectangular telescopic wing are presented. In order to avoid the complexity using aileron to generate rolling moment , an new idea that asymmetry of wings can generate roll moment is introduced. Finally, roll performance comparison of asymmetric wing and aileron deflection shows that asymmetric telescopic wing can provide the required roll control moment as aileron, and in some cases, telescopic wing has the superior roll performance.

  10. Morphological asymmetry and habitat quality: using fleas and their rodent hosts as a novel experimental system.

    Science.gov (United States)

    Warburton, Elizabeth M; Khokhlova, Irina S; Kiefer, Daniel; Krasnov, Boris R

    2017-04-01

    Morphological asymmetry is widely used to measure developmental instability and higher levels of asymmetry often correlate with decreased mating success, increased inbreeding, increased stress and decreased habitat quality. We studied asymmetry and relationships between asymmetry and host identity in two flea species, host generalist Xenopsylla ramesis and host specialist Parapulex chephrenis , and asked: (1) what the level of asymmetry was in their femurs and tibiae; (2) which type of asymmetry predominates; and (3) whether fleas that fed on host species distantly related to their principal host species produced offspring that exhibited greater asymmetry compared with offspring of fleas that fed on their principal host species. We found fluctuating asymmetry in femurs and tibiae of X. ramesis and in the tibiae of P. chephrenis as well as significantly left-handed directional asymmetry in the femurs of P. chephrenis Host species identity significantly impacted asymmetry in leg segments of P. chephrenis but not in those of X. ramesis Offspring asymmetry increased when mother fleas fed on a host that was distantly related to the principal host. Fleas parasitizing multiple host species might compensate for developmental instability when utilizing a novel host species; therefore, host-switching events in host-specific parasites could be constrained by the relatedness between a novel and a principal host species. © 2017. Published by The Company of Biologists Ltd.

  11. Effect of directional selection for body size on fluctuating asymmetry ...

    Indian Academy of Sciences (India)

    Madhsudhan

    of selection experiment. The selection experiment was continued for 10 generations. Throughout the study, a simple yeast agar culture medium containing agar-agar, crude sugar, dried yeast and active yeast (50:50), maize powder, nipagin, propionic acid and water was used. Flies were maintained in a BOD incubator at ...

  12. Fluctuating and Directional Asymmetry of the Blue Mussel (

    NARCIS (Netherlands)

    Lajus, D.; Katolikova, M.; Strelkov, P.; Hummel, H.

    2015-01-01

    In this work we examined morphological variation at different levels to study performance and population structuring of the blue mussel Mytilus edulis. Our objectives were: (i) to develop an integrated technique for analyzing morphological variation in blue mussels and, based on this technique; (ii)

  13. Symmetry, asymmetry and dissymmetry

    International Nuclear Information System (INIS)

    Wackenheim, A.; Zollner, G.

    1987-01-01

    The authors discuss the concept of symmetry and defect of symmetry in radiological imaging and recall the definition of asymmetry (congenital or constitutional) and dissymmetry (acquired). They then describe a rule designed for the cognitive method of automatic evaluation of shape recognition data and propose the use of reversal symmetry [fr

  14. Lepton asymmetry in B decays

    International Nuclear Information System (INIS)

    Wolfenstein, L.

    1998-01-01

    An estimate of the possible magnitude of the lepton asymmetry in B d decay is given in terms of observables. The asymmetry in B s decays is also discussed. It is concluded that the lepton asymmetry is not useful for detecting new physics in B-bar B mixing. copyright 1998 The American Physical Society

  15. Flow structure of vortex-wing interaction

    Science.gov (United States)

    McKenna, Christopher K.

    Impingement of a streamwise-oriented vortex upon a fin, tail, blade or wing represents a fundamental class of flow-structure interaction that extends across a range of applications. This interaction can give rise to time-averaged loading, as well as unsteady loading known as buffeting. The loading is sensitive to parameters of the incident vortex as well as the location of vortex impingement on the downstream aerodynamic surface, generically designated as a wing. Particle image velocimetry is employed to determine patterns of velocity, vorticity, swirl ratio, and streamlines on successive cross-flow planes upstream of and along the wing, which lead to volume representations and thereby characterization of the interaction. At locations upstream of the leading edge of the wing, the evolution of the incident vortex is affected by the presence of the wing, and is highly dependent on the spanwise location of vortex impingement. Even at spanwise locations of impingement well outboard of the wing tip, a substantial influence on the structure of the incident vortex at locations significantly upstream of the leading edge of the wing was observed. For spanwise locations close to or intersecting the vortex core, the effects of upstream influence of the wing on the vortex are to: decrease the swirl ratio; increase the streamwise velocity deficit; decrease the streamwise vorticity; increase the azimuthal vorticity; increase the upwash; decrease the downwash; and increase the root-mean-square fluctuations of both streamwise velocity and vorticity. The interrelationship between these effects is addressed, including the rapid attenuation of axial vorticity in presence of an enhanced defect of axial velocity in the central region of the vortex. Moreover, when the incident vortex is aligned with, or inboard of, the tip of the wing, the swirl ratio decreases to values associated with instability of the vortex, giving rise to enhanced values of azimuthal vorticity relative to the

  16. Vortex coupling in trailing vortex-wing interactions

    Science.gov (United States)

    Chen, C.; Wang, Z.; Gursul, I.

    2018-03-01

    The interaction of trailing vortices of an upstream wing with rigid and flexible downstream wings has been investigated experimentally in a wind tunnel, using particle image velocimetry, hot-wire, force, and deformation measurements. Counter-rotating upstream vortices exhibit increased meandering when they are close to the tip of the downstream wing. The upstream vortex forms a pair with the vortex shed from the downstream wing and then exhibits large displacements around the wing tip. This coupled motion of the pair has been found to cause large lift fluctuations on the downstream wing. The meandering of the vortex pair occurs at the natural meandering frequency of the isolated vortex, with a low Strouhal number, and is not affected by the frequency of the large-amplitude wing oscillations if the downstream wing is flexible. The displacement of the leading vortex is larger than that of the trailing vortex; however, it causes highly correlated variations of the core radius, core vorticity, and circulation of the trailing vortex with the coupled meandering motion. In contrast, co-rotating vortices do not exhibit any increased meandering.

  17. Wind tunnel investigation of the interaction and breakdown characteristics of slender wing vortices at subsonic, transonic, and supersonic speeds

    Science.gov (United States)

    Erickson, Gary E.

    1991-01-01

    The vortex dominated aerodynamic characteristics of a generic 65 degree cropped delta wing model were studied in a wind tunnel at subsonic through supersonic speeds. The lee-side flow fields over the wing-alone configuration and the wing with leading edge extension (LEX) added were observed at M (infinity) equals 0.40 to 1.60 using a laser vapor screen technique. These results were correlated with surface streamline patterns, upper surface static pressure distributions, and six-component forces and moments. The wing-alone exhibited vortex breakdown and asymmetry of the breakdown location at the subsonic and transonic speeds. An earlier onset of vortex breakdown over the wing occurred at transonic speeds due to the interaction of the leading edge vortex with the normal shock wave. The development of a shock wave between the vortex and wing surface caused an early separation of the secondary boundary layer. With the LEX installed, wing vortex breakdown asymmetry did not occur up to the maximum angle of attack in the present test of 24 degrees. The favorable interaction of the LEX vortex with the wing flow field reduced the effects of shock waves on the wing primary and secondary vortical flows. The direct interaction of the wing and LEX vortex cores diminished with increasing Mach number. The maximum attainable vortex-induced pressure signatures were constrained by the vacuum pressure limit at the transonic and supersonic speeds.

  18. Asymmetry, Symmetry and Beauty

    Directory of Open Access Journals (Sweden)

    Abbe R. Kopra

    2010-07-01

    Full Text Available Asymmetry and symmetry coexist in natural and human processes.  The vital role of symmetry in art has been well demonstrated. This article highlights the complementary role of asymmetry. Further we show that the interaction of asymmetric action (recursion and symmetric opposition (sinusoidal waves are instrumental in generating creative features (relatively low entropy, temporal complexity, novelty (less recurrence in the data than in randomized copies and complex frequency composition. These features define Bios, a pattern found in musical compositions and in poetry, except for recurrence instead of novelty. Bios is a common pattern in many natural and human processes (quantum processes, the expansion of the universe, gravitational waves, cosmic microwave background radiation, DNA, physiological processes, animal and human populations, and economic time series. The reduction in entropy is significant, as it reveals creativity and contradicts the standard claim of unavoidable decay towards disorder. Artistic creations capture fundamental features of the world.

  19. Bessel Weighted Asymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Avakian, Harut [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Gamberg, Leonard [Pennsylvania State Univ., University Park, PA (United States); Rossi, Patrizia [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Prokudin, Alexei [Pennsylvania State Univ., University Park, PA (United States)

    2016-05-01

    We review the concept of Bessel weighted asymmetries for semi-inclusive deep inelastic scattering and focus on the cross section in Fourier space, conjugate to the outgoing hadron’s transverse momentum, where convolutions of transverse momentum dependent parton distribution functions and fragmentation functions become simple products. Individual asymmetric terms in the cross section can be projected out by means of a generalized set of weights involving Bessel functions. The procedure is applied to studies of the double longitudinal spin asymmetry in semi-inclusive deep inelastic scattering using a new dedicated Monte Carlo generator which includes quark intrinsic transverse momentum within the generalized parton model. We observe a few percent systematic offset of the Bessel-weighted asymmetry obtained from Monte Carlo extraction compared to input model calculations, which is due to the limitations imposed by the energy and momentum conservation at the given energy and hard scale Q2. We find that the Bessel weighting technique provides a powerful and reliable tool to study the Fourier transform of TMDs with controlled systematics due to experimental acceptances and resolutions with different TMD model inputs.

  20. Fluctuation analysis

    International Nuclear Information System (INIS)

    Clarke, J.

    1980-01-01

    This paper briefly reviews sources of noise in Josephson junctions, and the limits they impose on the sensitivity of dc and rf SQUIDS. The results are strictly valid only for a resistively shunted junction (RSJ) with zero capacitance, but should be applicable to point contact junctions and microbridges in so far as these devices can be approximated by the RSJ model. Fluctuations arising from Nyquist noise in the resistive shunt of a single junction are discussed in the limit eI/sub o/R/k/sub B/T << 1 in which a classical treatment is appropriate, and then extend the treatment to the limit eI/sub o/R/k/sub B/T greater than or equal to 1 in which quantum effects become important. The Nyquist limit theory is used to calculate the noise in a dc SQUID, and the results are compared with a number of practical devices. The quantum limit is briefly considered. Results for the predicted sensitivity of rf SQUIDS are presented, and also compared with a number of practical devices. Finally, the importance of l/f noise (f is the frequency) in limiting the low frequency performance of SQUIDS is discussed

  1. [Lateralization of behavioral reactions and otolith asymmetry].

    Science.gov (United States)

    Lychakov, D V

    2013-01-01

    Lateralized behavior is widely spread among vertebrate animals and is determined first of ally by structural-functional brain asymmetry as well as by the presence of somatic and visceral asymmetry. Some kinds of asymmetric reactions are suggested to be due to the presence of asymmetry at the level of sense organs, in particular, of otolith organs. This review presents data on value and character of otolith asymmetry (OA) in animals of various species and classes, on action upon it of weightlessness and hypergravity; the problem of effect of OA on vestibular and auditory functions is considered. In symmetric vertebrates, OA has been shown to be of fluctuation character and its chi coefficient varies in diapason from -0.2 to 0.2; in the overwhelmed majority of individuals, /chi/ otolith organs to work coordinately; this it why OA is at the equally low level regardless of the individual's taxonomic and ecologic position, its size, age, and otolith growth rate. Individuals with abnormally high OA level can experience difficulties in analysis of auditory and vestibular stimuli, therefore in nature the majority of such individuals are eliminated in the process of natural selection. Unlike symmetrical vertebrates, labyrinths of many Pleuronectiformes have pronounced OA--otoliths of the lower labyrinth, on a average, are significantly heavier than those of the upper labyrinth. Their organs are the only example when OA with directed character seem to play an essential role in lateralized behavior and are suggested to be used in the spatial localization of the sound source. The short-time action of weightlessness and relatively weak hypergravity ( or = 3g, as well as some diseases and shifts connected with processes of aging can enhance OA and cause several functional disturbances.

  2. Pigeons produce aerodynamic torques through changes in wing trajectory during low speed aerial turns.

    Science.gov (United States)

    Ros, Ivo G; Badger, Marc A; Pierson, Alyssa N; Bassman, Lori C; Biewener, Andrew A

    2015-02-01

    The complexity of low speed maneuvering flight is apparent from the combination of two critical aspects of this behavior: high power and precise control. To understand how such control is achieved, we examined the underlying kinematics and resulting aerodynamic mechanisms of low speed turning flight in the pigeon (Columba livia). Three birds were trained to perform 90 deg level turns in a stereotypical fashion and detailed three-dimensional (3D) kinematics were recorded at high speeds. Applying the angular momentum principle, we used mechanical modeling based on time-varying 3D inertia properties of individual sections of the pigeon's body to separate angular accelerations of the torso based on aerodynamics from those based on inertial effects. Directly measured angular accelerations of the torso were predicted by aerodynamic torques, justifying inferences of aerodynamic torque generation based on inside wing versus outside wing kinematics. Surprisingly, contralateral asymmetries in wing speed did not appear to underlie the 90 deg aerial turns, nor did contralateral differences in wing area, angle of attack, wingbeat amplitude or timing. Instead, torso angular accelerations into the turn were associated with the outside wing sweeping more anteriorly compared with a more laterally directed inside wing. In addition to moving through a relatively more retracted path, the inside wing was also more strongly pronated about its long axis compared with the outside wing, offsetting any difference in aerodynamic angle of attack that might arise from the observed asymmetry in wing trajectories. Therefore, to generate roll and pitch torques into the turn, pigeons simply reorient their wing trajectories toward the desired flight direction. As a result, by acting above the center of mass, the net aerodynamic force produced by the wings is directed inward, generating the necessary torques for turning. © 2015. Published by The Company of Biologists Ltd.

  3. The design and testing of subscale smart aircraft wing bolts

    International Nuclear Information System (INIS)

    Vugampore, J M V; Bemont, C

    2012-01-01

    Presently costly periodic inspection is vital in guaranteeing the structural integrity of aircraft. This investigation assesses the potential for significantly reducing aircraft maintenance costs without modification of aircraft structures by implementing smart wing bolts, manufactured from TRIP steel, which can be monitored for damage in situ. TRIP steels undergo a transformation from paramagnetic austenite to ferromagnetic martensite during deformation. Subscale smart aircraft wing bolts were manufactured from hot rolled TRIP steel. These wing bolts were used to demonstrate that washers incorporating embedded inductance coils can be utilized to measure the martensitic transformation occurring in the TRIP steel during bolt deformation. Early in situ warning of a critical bolt stress level was thereby facilitated, potentially reducing the costly requirement for periodic wing bolt removal and inspection. The hot rolled TRIP steels that were utilized in these subscale bolts do not however exhibit the mechanical properties required of wing bolt material. Thus warm rolled TRIP steel alloys were also investigated. The mechanical properties of the best warm rolled TRIP steel alloy tested almost matched those of AISI 4340. The warm rolled alloys were also shown to exhibit transformation before yield, allowing for earlier warning when overload occurs. Further work will be required relating to fatigue crack detection, environmental temperature fluctuation and more thorough material characterization. However, present results show that in situ early detection of wing bolt overload is feasible via the use of high alloy warm rolled TRIP steel wing bolts in combination with inductive sensor embedded washers. (paper)

  4. Strength Asymmetry Increases Gait Asymmetry and Variability in Older Women

    Science.gov (United States)

    LaRoche, Dain P.; Cook, Summer B.; Mackala, Krzysztof

    2012-01-01

    Purpose The aim of the research was to determine how knee extensor strength asymmetry influences gait asymmetry and variability since these gait parameters have been related to mobility and falls in older adults. Methods Strength of the knee extensors was measured in 24 older women (65 – 80 yr). Subjects were separated into symmetrical strength (SS, n = 13) and asymmetrical strength (SA, n = 11) groups using an asymmetry cutoff of 20%. Subjects walked at a standard speed of 0.8 m s−1 and at maximal speed on an instrumented treadmill while kinetic and spatiotemporal gait variables were measured. Gait and strength asymmetry were calculated as the percent difference between legs and gait variability as the coefficient of variation over twenty sequential steps. Results SA had greater strength asymmetry (27.4 ± 5.5%) than SS (11.7 ± 5.4%, P speeds, SA had greater single (7.1% vs. 2.5%) and double-limb support time asymmetry (7.0 vs. 4.3%) than SS and greater single-limb support time variability (9.7% vs. 6.6%, all P speed interactions occurred for weight acceptance force variability (P = 0.02) and weight acceptance force asymmetry (P = 0.017) with greater variability at the maximal speed in SA (5.0 ± 2.4% vs. 3.7 ± 1.2%) and greater asymmetry at the maximal speed in SA (6.4 ± 5.3% vs. 2.5 ± 2.3%). Conclusion Gait variability and asymmetry are greater in older women with strength asymmetry and increase when they walk near their maximal capacities. The maintenance of strength symmetry, or development of symmetry through unilateral exercise, may be beneficial in reducing gait asymmetry, gait variability, and fall risk in older adults. PMID:22617401

  5. LHCb Semileptonic Asymmetry

    CERN Document Server

    Vesterinen, Mika

    2013-01-01

    A recent LHCb measurement of the CP violating flavour specific asymmetry in $B_s^0$ decays, $a^s_{ls}$, is presented. This measurement is based on a data sample corresponding to an integrated luminosity of 1 fb$^{-1}$ of $pp$ collisions at $\\sqrt{s}$ $=$ 7 TeV, collected during the 2011 run of the LHC. The result is $a^s_{ls} = (-0.24 \\pm 0.54_{\\rm stat} \\pm 0.33_{\\rm syst})\\times 10^{-2}$, which is the most precise measurement of this quantity to date and agrees with the Standard Model prediction.

  6. Origins of the di-jet asymmetry in heavy ion collisions

    CERN Document Server

    Milhano, José Guilherme

    2016-01-01

    The di-jet asymmetry --- the measure of the momentum imbalance in a di-jet system --- is a key jet quenching observable. Using the event generator \\jewel we show that the di-jet asymmetry is dominated by fluctuations both in proton-proton and in heavy ion collisions. We discuss how in proton-proton collisions the asymmetry is generated through recoil and out-of-cone radiation. In heavy ion collisions two additional sources contribute to the asymmetry, namely energy loss fluctuations and differences in path length. The latter is shown to be a sub-leading effect. We discuss the implications of our results for the interpretation of this observable.

  7. Poloidal asymmetries of flows in the Tore Supra tokamak

    Science.gov (United States)

    Vermare, L.; Hennequin, P.; Gürcan, Ö. D.; Garbet, X.; Honoré, C.; Clairet, F.; Giacalone, J. C.; Morel, P.; Storelli, A.; Tore Supra Team

    2018-02-01

    Simultaneous measurements of binormal velocity of density fluctuations using two separate Doppler backscattering systems at the low field side and at the top of the plasma show significant poloidal asymmetry. The measurements are performed in the core region between the radii 0.7 Supra tokamak. A possible generation mechanism by the ballooned structure of the underlying turbulence, in the form of convective cells, is proposed for explaining the observation of these poloidally asymmetric mean flows.

  8. Fluctuations in quantum chaos

    International Nuclear Information System (INIS)

    Casati, G.; Chirikov, B.V.

    1996-01-01

    Various fluctuations in quantum systems with discrete spectrum are discussed, including recent unpublished results. Open questions and unexplained peculiarities of quantum fluctuations are formulated [ru

  9. Fluctuations in Cerebral Hemodynamics

    National Research Council Canada - National Science Library

    Latka, Miroslaw

    2003-01-01

    We demonstrate that the scaling properties of intracranial pressure (ICP) fluctuations and fluctuations of blood flow velocity in middle cerebral arteries are characterized by two scaling exponents...

  10. Matter-antimatter asymmetry

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    The Conference is devoted to a multidisciplinary study of matter-antimatter asymmetry and, in particular, from the point of view of particle physics, astrophysics and cosmology. A number of topics, such as the practical applications of antimatter in medical imaging, of particular interest to non-specialists, will also be briefly covered. More than thirty years after the discovery of CP violation in the kaon system, precision experiments with kaons at CERN and Fermilab have demonstrated the existence of direct CP violation, opening a window on a hitherto poorly explored part of particle physics. On the one hand, two experiments devoted mainly to CP violation in B mesons, BABAR and Belle, are beginning to test CP violation in the Standard Model in a decisive way. On the other hand, balloon experiments and the space-based AMS project are circumscribing precise limits on the cosmological abundance of antimatter. Finally, the fundamental problem of cosmological matter-antimatter asymmetry at a Grand Unification scale or at the Electroweak phase transition has been the object of intense theoretical activity in recent years. This document gathers most of the slides that have been presented in the plenary and parallel sessions.

  11. Evidence from intrinsic activity that asymmetry of the human brain is controlled by multiple factors.

    Science.gov (United States)

    Liu, Hesheng; Stufflebeam, Steven M; Sepulcre, Jorge; Hedden, Trey; Buckner, Randy L

    2009-12-01

    Cerebral lateralization is a fundamental property of the human brain and a marker of successful development. Here we provide evidence that multiple mechanisms control asymmetry for distinct brain systems. Using intrinsic activity to measure asymmetry in 300 adults, we mapped the most strongly lateralized brain regions. Both men and women showed strong asymmetries with a significant, but small, group difference. Factor analysis on the asymmetric regions revealed 4 separate factors that each accounted for significant variation across subjects. The factors were associated with brain systems involved in vision, internal thought (the default network), attention, and language. An independent sample of right- and left-handed individuals showed that hand dominance affects brain asymmetry but differentially across the 4 factors supporting their independence. These findings show the feasibility of measuring brain asymmetry using intrinsic activity fluctuations and suggest that multiple genetic or environmental mechanisms control cerebral lateralization.

  12. Exchange asymmetry in experimental settings

    Science.gov (United States)

    Thomas C. Brown; Mark D. Morrison; Jacob A. Benfield; Gretchen Nurse Rainbolt; Paul A. Bell

    2015-01-01

    We review past trading experiments and present 11 new experiments designed to show how the trading rate responds to alterations of the experimental procedure. In agreement with earlier studies, results show that if the trade decision is converted to one resembling a choice between goods the exchange asymmetry disappears, but otherwise the asymmetry is...

  13. Longitudinal fluctuations and decorrelation of anisotropic flow

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Long-Gang [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, 60438 Frankfurt am Main (Germany); Petersen, Hannah [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, 60438 Frankfurt am Main (Germany); Institute for Theoretical Physics, Goethe University, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main (Germany); GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); Qin, Guang-You [Key Laboratory of Quark & Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); Roy, Victor [Institute for Theoretical Physics, Goethe University, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Wang, Xin-Nian [Key Laboratory of Quark & Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); Nuclear Science Division MS70R0319, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2016-12-15

    We investigate the decorrelation of 2nd and 3rd order anisotropic flow for charged particles in two different pseudo rapidity (η) windows by varying the pseudo rapidity gap, in an event-by-event (3+1)D ideal hydrodynamic model, with fluctuating initial conditions from A Multi-Phase Transport (AMPT) model. We visualize the parton distribution at initial state for Pb+Pb collisions at LHC and Au+Au collisions at RHIC, and demonstrate the longitudinal fluctuations originating from the asymmetry between forward and backward going participants, the fluctuations of the string length and the fluctuations due to finite number of partons at different beam energies. The decorrelation of anisotropic flow of final hadrons with large η gaps is found to originate from the spatial decorrelation along the longitudinal direction in the AMPT initial conditions through hydrodynamic evolution. The agreement between our results and recent CMS data in most centralities suggests that the string-like mechanism of initial parton production in AMPT model captures the initial longitudinal fluctuation that is responsible for the measured decorrelation of anisotropic flow in Pb+Pb collisions at LHC. Our predictions for Au+Au collisions at the highest RHIC energy show stronger longitudinal decorrelation than at LHC, indicating larger longitudinal fluctuations at lower beam energies.

  14. WINGS Data Release

    DEFF Research Database (Denmark)

    Moretti, A.; Poggianti, B. M.; Fasano, G.

    2014-01-01

    Context. To effectively investigate galaxy formation and evolution, it is of paramount importance to exploit homogeneous data for large samples of galaxies in different environments. Aims. The WIde-field Nearby Galaxy-cluster Survey (WINGS) project aim is to evaluate physical properties of galaxies...... in a complete sample of low redshift clusters to be used as reference sample for evolutionary studies. The WINGS survey is still ongoing and the original dataset will be enlarged with new observations. This paper presents the entire collection of WINGS measurements obtained so far. Methods. We decided to make......, and on the cluster redshift, reaching on average 90% at V ≲ 21.7. Near-infrared photometric catalogs for 26 (in K) and 19 (in J) clusters are part of the database and the number of sources is 962 344 in K and 628 813 in J. Here again the completeness depends on the data quality, but it is on average higher than 90...

  15. Fluctuations and symmetry energy in nuclear fragmentation dynamics.

    Science.gov (United States)

    Colonna, M

    2013-01-25

    Within a dynamical description of nuclear fragmentation, based on the liquid-gas phase transition scenario, we explore the relation between neutron-proton density fluctuations and nuclear symmetry energy. We show that, along the fragmentation path, isovector fluctuations follow the evolution of the local density and approach an equilibrium value connected to the local symmetry energy. Higher-density regions are characterized by smaller average asymmetry and narrower isotopic distributions. This dynamical analysis points out that fragment final state isospin fluctuations can probe the symmetry energy of the density domains from which fragments originate.

  16. Wing kinematics measurement and aerodynamics of a dragonfly in turning flight.

    Science.gov (United States)

    Li, Chengyu; Dong, Haibo

    2017-02-03

    This study integrates high-speed photogrammetry, 3D surface reconstruction, and computational fluid dynamics to explore a dragonfly (Erythemis Simplicicollis) in free flight. Asymmetric wing kinematics and the associated aerodynamic characteristics of a turning dragonfly are analyzed in detail. Quantitative measurements of wing kinematics show that compared to the outer wings, the inner wings sweep more slowly with a higher angle of attack during the downstroke, whereas they flap faster with a lower angle of attack during the upstroke. The inner-outer asymmetries of wing deviations result in an oval wingtip trajectory for the inner wings and a figure-eight wingtip trajectory for the outer wings. Unsteady aerodynamics calculations indicate significantly asymmetrical force production between the inner and outer wings, especially for the forewings. Specifically, the magnitude of the drag force on the inner forewing is approximately 2.8 times greater than that on the outer forewing during the downstroke. In the upstroke, the outer forewing generates approximately 1.9 times greater peak thrust than the inner forewing. To keep the body aloft, the forewings contribute approximately 64% of the total lift, whereas the hindwings provide 36%. The effect of forewing-hindwing interaction on the aerodynamic performance is also examined. It is found that the hindwings can benefit from this interaction by decreasing power consumption by 13% without sacrificing force generation.

  17. Asymmetry a challenge for orthodontists

    DEFF Research Database (Denmark)

    Melsen, Birte

    2007-01-01

      Asymmetry is considered a challenge and often the reason for which the optimal result cannot be obtained. The explanations are many. Only rarely, the cause of the asymmetry is localized and camouflage is frequently resulting in the development a different type of asymmetry occurring in all thre...... the required tooth displacements can be generated. In order to control the interaction between the force systems developed in the three planes of space, the appliances should commonly be segmented. Anchorage problems can occasionally only be solved by means of skeletal anchorage....

  18. WHEN COMPASSION GROWS WINGS

    African Journals Online (AJOL)

    Nicky

    antiretroviral roll-out in full swing, the. WHEN COMPASSION GROWS WINGS. The free time and expertise given by its deeply committed core of professional volunteers. (including pilots) is the lifeblood of the operation. Red Cross Air Mercy Service volunteer, German national Dr Florian Funk, at the AMS Durban base.

  19. Twisted Winged Endoparasitoids

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 10. Twisted Winged Endoparasitoids - An Enigma for Entomologists. Alpana Mazumdar. General Article Volume 9 Issue 10 October 2004 pp 19-24. Fulltext. Click here to view fulltext PDF. Permanent link:

  20. [Dreams and interhemispheric asymmetry].

    Science.gov (United States)

    Korabel'nikova, E A; Golubev, V L

    2001-01-01

    The dreams of 103 children and adolescents, aged 10-17 years, have been studied. The test group included 78 patients with neurotic disorders; control one consisted of 25 healthy subjects. Dream features, which were common for those with preferentially left asymmetry profile both in patients as well as in healthy subjects, were: less expressed novelty factor and frequent appearance of rare phenomena, such as "déjà vu in wakefulness", reality, "mixed" (overlapped) dreams, prolonged dreams in repeat sleep, frequent changes of personages and scenes of action. Left-hander dream peculiarities, being detected only in neurotic patients but not in healthy subjects, emerged as lucid phenomena deficit, "dream in dreams" and "dream reminiscence in dream" syndrome, which have been found only in left-handers. Right and left hemispheres seem to contribute in different ways to a dream formation. In authors believe that the left hemisphere seems to provide dream origin while the right hemisphere provides dream vividness, figurativeness and affective activation level.

  1. Looking for charming asymmetries

    CERN Multimedia

    Stefania Pandolfi

    2016-01-01

    New results presented by the LHCb collaboration on the decay of particles containing a “charm” quark delve deeper into the mystery of matter-antimatter asymmetry.   A view of the LHCb experimental cavern. (Photo: Maximilien Brice/CERN) One of the biggest challenges in physics is to understand why everything we see in our universe seems to be formed only of matter, whereas the Big Bang should have created equal amounts of matter and antimatter. CERN’s LHCb experiment is one of the best hopes for physicists looking to solve this longstanding mystery. At the VIII International Workshop on Charm Physics, which took place in Bologna earlier this month, the LHCb Collaboration presented the most precise measurement to date of a phenomenon called Charge-Parity (CP) violation among particles that contain a charm quark. CP symmetry states that laws of physics are the same if a particle is interchanged with its anti-particle (the “C” part) and if its spatia...

  2. Information Asymmetry and Credit Risk

    Directory of Open Access Journals (Sweden)

    Lorena TUPANGIU

    2017-11-01

    Full Text Available Information asymmetry defines relationships where an agent holds information while another does not hold it. Thus, to the extent that one of the parties to the financing agreement has information more or less accurate than another, the asymmetry of information appears to be a major constraint in the financing of a project. Banks, in their capacity of financial intermediary, operate the transfer of funds to agents in need of financing, to the borrowers, being necessary in this process to have more information in order to benefit of expertise in assessing borrowers. The research of information asymmetry and credit risk consists of interrogating the following aspects: information issues between the bank and borrowers; settlement of information issues; bank’s activism towards information asymmetry. In our approach we will look at the first aspect, namely the information issues between the bank and the borrowers.

  3. Hemispheric asymmetries: The comparative view

    Directory of Open Access Journals (Sweden)

    Sebastian eOcklenburg

    2012-01-01

    Full Text Available Hemispheric asymmetries play an important role in almost all cognitive functions. For more than a century, they were considered to be uniquely human but now an increasing number of findings in all vertebrate classes make it likely that we inherited our asymmetries from common ancestors. Thus, studying animal models could provide unique insights into the mechanisms of lateralization. We outline three such avenues of research by providing an overview of experiments on left-right differences in the connectivity of sensory systems, the embryonic determinants of brain asymmetries, and the genetics of lateralization. All these lines of studies could provide a wealth of insights into our own asymmetries that should and will be exploited by future analyses.

  4. Shared Pattern of Endocranial Shape Asymmetries among Great Apes, Anatomically Modern Humans, and Fossil Hominins

    Science.gov (United States)

    Balzeau, Antoine; Gilissen, Emmanuel; Grimaud-Hervé, Dominique

    2012-01-01

    Anatomical asymmetries of the human brain are a topic of major interest because of their link with handedness and cognitive functions. Their emergence and occurrence have been extensively explored in human fossil records to document the evolution of brain capacities and behaviour. We quantified for the first time antero-posterior endocranial shape asymmetries in large samples of great apes, modern humans and fossil hominins through analysis of “virtual” 3D models of skull and endocranial cavity and we statistically test for departures from symmetry. Once based on continuous variables, we show that the analysis of these brain asymmetries gives original results that build upon previous analysis based on discrete traits. In particular, it emerges that the degree of petalial asymmetries differs between great apes and hominins without modification of their pattern. We indeed demonstrate the presence of shape asymmetries in great apes, with a pattern similar to modern humans but with a lower variation and a lower degree of fluctuating asymmetry. More importantly, variations in the position of the frontal and occipital poles on the right and left hemispheres would be expected to show some degree of antisymmetry when population distribution is considered, but the observed pattern of variation among the samples is related to fluctuating asymmetry for most of the components of the petalias. Moreover, the presence of a common pattern of significant directional asymmetry for two components of the petalias in hominids implicates that the observed traits were probably inherited from the last common ancestor of extant African great apes and Homo sapiens. These results also have important implications for the possible relationships between endocranial shape asymmetries and functional capacities in hominins. It emphasizes the uncoupling between lateralized activities, some of them well probably distinctive to Homo, and large-scale cerebral lateralization itself, which is not

  5. Lepton asymmetries from neutrino oscillations

    International Nuclear Information System (INIS)

    Volkas, R.R.

    2000-01-01

    Reasonably large relic neutrino asymmetries can be generated by active-sterile neutrino oscillations. After briefly discussing possible applications, I describe the Quantum Kinetic Equation formalism used to compute the asymmetry growth curves. I then show how the basic features of these curves can be understood on the basis of the adiabatic limit approximation in the collision dominated epoch, and the pure MSW effect at lower temperatures (author)

  6. Asymmetry of eye color in the common cuckoo.

    Science.gov (United States)

    Yoo, Ha-Na; Lee, Jin-Won; Yoo, Jeong-Chil

    2017-08-08

    Bilateral symmetry is assumed to contribute to the evolution of eye color, with the left and right eye being the same color in most vertebrates; yet, few studies tested this assumption. Here, we compared the amount of iris flecking (black spots presented on the iris) between the left and right eye of 76 adult common cuckoos Cuculus canorus. We found considerable variation in the total amount of iris flecking among individuals, with variation being associated with body size and sex. We also found that the amount of iris flecking differed between the left and right eye and that this left-right asymmetry was not random, with the left eye almost always being darker than the right eye. Furthermore, this asymmetry was negatively associated with wing length; however, this effect was limited to individuals with dark eyes. Overall, the asymmetric, but non-random, distribution of iris flecking between the left and right eye may indicate that selection pressures driving asymmetry (such as visual lateralization) act on the development of iris colors, even though this effect might be limited, due to the role of bilateral symmetry.

  7. Fluctuations in LC Oscillators

    Directory of Open Access Journals (Sweden)

    O. Ondracek

    1994-03-01

    Full Text Available An analysis of the phase and amplitude fluctuations in oscillators with simple resonant circuit is presented. Negative feedback is used to minimize effect of the inherent noise produced by bipolar transistor on fluctuation characteristics.

  8. Critical asymmetry in renormalization group theory for fluids

    Science.gov (United States)

    Zhao, Wei; Wu, Liang; Wang, Long; Li, Liyan; Cai, Jun

    2013-06-01

    The renormalization-group (RG) approaches for fluids are employed to investigate critical asymmetry of vapour-liquid equilibrium (VLE) of fluids. Three different approaches based on RG theory for fluids are reviewed and compared. RG approaches are applied to various fluid systems: hard-core square-well fluids of variable ranges, hard-core Yukawa fluids, and square-well dimer fluids and modelling VLE of n-alkane molecules. Phase diagrams of simple model fluids and alkanes described by RG approaches are analyzed to assess the capability of describing the VLE critical asymmetry which is suggested in complete scaling theory. Results of thermodynamic properties obtained by RG theory for fluids agree with the simulation and experimental data. Coexistence diameters, which are smaller than the critical densities, are found in the RG descriptions of critical asymmetries of several fluids. Our calculation and analysis show that the approach coupling local free energy with White's RG iteration which aims to incorporate density fluctuations into free energy is not adequate for VLE critical asymmetry due to the inadequate order parameter and the local free energy functional used in the partition function.

  9. Winging of the Scapula in a Young Athlete.

    Science.gov (United States)

    Patel; Nelson

    1996-10-01

    A 15-year-old high school football player noticed asymmetry of his right shoulder and thought that he was losing muscle mass around his right shoulder over the previous 2-3 weeks. There was no history of pain, recent or past direct trauma or surgery of the neck or thorax. He was diagnosed with serologically confirmed infectious mononucleosis about 2 months earlier, and was recovering clinically. Physical examination was normal, except for significant asymmetry and winging of the right scapula, and electromyographic and nerve conduction studies revealed demyealination and axonal damage to the right long thoracic nerve and paralysis of serratus anterior, most likely caused by Epstein-Barr virus infection. Conservative treatment approach allowing continued activity and strengthening exercises resulted in full functional recovery over the next 6-8 months.

  10. Left-right asymmetries and shape analysis on Ceroglossus chilensis (Coleoptera: Carabidae)

    Science.gov (United States)

    Bravi, Raffaella; Benítez, Hugo A.

    2013-10-01

    Bilateral symmetry is widespread in animal kingdom, however most animal can deviate from expected symmetry and manifest some kind of asymmetries. Fluctuating asymmetry is considered as a tool for valuating developmental instability, whereas directional asymmetry is inherited and could be used for evaluating evolutionary development. We use the method of geometric morphometrics to analyze left/right asymmetries in the whole body, in two sites and totally six populations of Ceroglossus chilensis with the aim to infer and explain morphological disparities between populations and sexes in this species. In all individuals analyzed we found both fluctuating asymmetry and directional asymmetry for size and shape variation components, and a high sexual dimorphism. Moreover a high morphological variability between the two sites emerged as well. Differences in diet could influence the expression of morphological variation and simultaneously affect body sides, and therefore contribute to the symmetric component of variation. Moreover differences emerged between two sites could be a consequence of isolation and fragmentation, rather than a response to local environmental differences between sampling sites.

  11. Menstrual Cycle-Related Changes of Functional Cerebral Asymmetries in Fine Motor Coordination

    Science.gov (United States)

    Bayer, Ulrike; Hausmann, Markus

    2012-01-01

    Fluctuating sex hormone levels during the menstrual cycle have been shown to affect functional cerebral asymmetries in cognitive domains. These effects seem to result from the neuromodulatory properties of sex hormones and their metabolites on interhemispheric processing. The present study was carried out to investigate whether functional cerebral…

  12. Design optimization of deployable wings

    Science.gov (United States)

    Gaddam, Pradeep

    Morphing technology is an important aspect of UAV design, particularly in regards to deployable systems. The design of such system has an important impact on the vehicle's performance. The primary focus of the present research work was to determine the most optimum deployable wing design from 3 competing designs and develop one of the deployable wing designs to test in the research facility. A Matlab code was developed to optimize 3 deployable wing concepts inflatable, inflatable telescopic and rigid-folding wings based on a sequential optimization strategy. The constraints that were part of the code include the packaging constraints during its stowed state, fixed length of the deployed section and the minimum L/D constraint. This code resulted in determining the optimum weight of all the 3 designs, the most optimum weight design is the inflatable wing design. This is a result of the flexible skin material and also due to no rigid parts in the deployed wing section. Another goal of the research involved developing an inflatable telescopic wing. The prototype was tested in a wind tunnel, while the actual wing was tested in the altitude chamber to determine the deployment speed, input pressure, analyze and predict the deployment sequence and behavior of the wing at such high wind speeds and altitudes ranging from 60,000 ft to 90,000 ft. Results from these tests allowed us to conclude the deployment sequence of the telescopic wing followed from the root to the tip section. The results were used to analyze the deployment time of the wing. As expected the deployment time decreased with an increase in input pressure. The results also show us that as the altitude increases, the deployment speed of the wing also increased. This was demonstrated when the wing was tested at a maximum altitude pressure of 90,000ft, well above the design altitude of 60,000ft.

  13. Behavioral approach system sensitivity and risk taking interact to predict left-frontal EEG asymmetry.

    Science.gov (United States)

    Black, Chelsea L; Goldstein, Kim E; LaBelle, Denise R; Brown, Christopher W; Harmon-Jones, Eddie; Abramson, Lyn Y; Alloy, Lauren B

    2014-09-01

    The Behavioral Approach System (BAS) hypersensitivity theory of bipolar disorder (BD; Alloy & Abramson, 2010; Depue & Iacono, 1989) suggests that hyperreactivity in the BAS results in the extreme fluctuations of mood characteristic of BD. In addition to risk conferred by BAS hypersensitivity, cognitive and personality variables may play a role in determining risk. We evaluated relationships among BAS sensitivity, risk taking, and an electrophysiological correlate of approach motivation, relative left-frontal electroencephalography (EEG) asymmetry. BAS sensitivity moderated the relationship between risk taking and EEG asymmetry. More specifically, individuals who were high in BAS sensitivity showed left-frontal EEG asymmetry regardless of their level of risk-taking behavior. However, among individuals who were moderate in BAS sensitivity, risk taking was positively associated with asymmetry. These findings suggest that cognitive and personality correlates of bipolar risk may evidence unique contributions to a neural measure of trait-approach motivation. Clinical implications of these findings are discussed. Copyright © 2014. Published by Elsevier Ltd.

  14. Low Aspect-Ratio Wings for Wing-Ships

    DEFF Research Database (Denmark)

    Filippone, Antonino; Selig, M.

    1998-01-01

    Flying on ground poses technical and aerodynamical challenges. The requirements for compactness, efficiency, manouverability, off-design operation,open new areas of investigations in the fieldof aerodynamic analysis and design. A review ofthe characteristics of low-aspect ratio wings, in- and out...... of ground, is presented. It is shownthat the performance of such wings is generally inferior to that of slender wings, although in ground placement can yield substantial improvements in the aerodynamic efficiency....

  15. Wing-vortex interaction: unraveling the flowfield of a hovering rotor

    Science.gov (United States)

    Bhagwat, Mahendra J.; Caradonna, Francis X.; Ramasamy, Manikandan

    2015-01-01

    This paper focuses on one of the most prominent flow features of the hovering rotor wake, the close interaction of the tip vortex with a following blade. Such vortex interactions are fundamental determinants of rotor performance, loads, and noise. Yet, they are not completely understood, largely due to the lack of sufficiently comprehensive experimental data. The present study aims to perform such comprehensive measurements, not on hovering helicopter rotors (which hugely magnifies test complexity) but using fixed-wing models in controlled wind tunnel tests. The experiments were designed to measure, in considerable detail, the aerodynamic loading resulting from a vortex interacting with a semi-span wing, as well as the wake resulting from that interaction. The goal of the present study is to answer fundamental questions such as (a) the influence of a vortex passing below a wing on the lift, drag, tip vortex, and the wake of that wing and (b) the strength of the forming tip vortex and its relation to the wing loading and/or the tip loading. This paper presents detailed wing surface pressure measurements that result from the interaction of the wing with an interacting vortex trailing from an upstream wing. The data show large lift distribution changes for a range of wing-vortex interactions including the effects of close encounter with the vortex core. Significant asymmetry in the vortex-induced lift loading was observed, with the increase in wing sectional lift outboard of the interacting vortex (closer to the tip) being much smaller than the corresponding decrease inboard of the vortex.

  16. [Increased Size of Epidermal Cells in Syringa josikaea Jacq. Smaller Leaf Side as an Adaptive Mechanism for Reducing Its Asymmetry].

    Science.gov (United States)

    Polonskii, V I; Polyakova, I S

    2015-01-01

    Comparative study of quantitative anatomy of the epidermis in Syringa josikaea Jacq. leaf halves of different width was conducted in order to analyze the possible mechanism of formation of the value of fluctuating leaf asymmetry. A regular decrease in the density of main epidermal cells in the smaller leaf half compared with the bigger one was traced during leaf ontogeny. Stomatal index was equal in different-sized leaf halves. Adaptive response was found in fully formed leaves; it was aimed at reducing leaf blade fluctuating asymmetry by 23% on average and consisted of compensatory growth--further elongation of main epidermal cells in the smaller half of the leaf. It was concluded that the level of fluctuating leaf asymmetry in Hungary lilac is mainly due to a lower rate of cell division, as well as due to their greater elongation in the smaller half of adult leaf compared with the bigger half.

  17. Flavor asymmetry of the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Bijker, R. [Instituto de Ciencias Nucleares, UNAM, Apartado Postal 70-543, 04510 Mexico D. F. (Mexico); Santopinto, E. [INFN and Dipartimento di Fisica, Via Dodecaneso 33, I-16146 Genova (Italy)]. e-mail: bijker@nucleares.unam.mx

    2008-12-15

    The flavor asymmetry of the nucleon sea is discussed in an unquenched quark model for baryons in which the effects of quark-antiquark pairs (uu, dd and ss) are taken into account in an explicit form. The inclusion of qq pairs leads automatically to an excess of d over u quarks in the proton, in agreement with experimental data. (Author)

  18. Complex Odontome Causing Facial Asymmetry

    Directory of Open Access Journals (Sweden)

    Karthikeya Patil

    2006-01-01

    Full Text Available Odontomas are the most common non-cystic odontogenic lesions representing 70% of all odontogenic tumors. Often small and asymptomatic, they are detected on routine radiographs. Occasionally they become large and produce expansion of bone with consequent facial asymmetry. We report a case of such a lesion causing expansion of the mandible in an otherwise asymptomatic patient.

  19. Analysis of side writing asymmetry

    NARCIS (Netherlands)

    Hozoi, A.; Groenland, J.P.J.; Albertini, J.B.; Lodder, J.C.

    2003-01-01

    The side writing asymmetry of a recording head was investigated using an overwrite configuration that enhances the edge effects. The track profiles of the overwrite patterns were measured for analyzing the side writing performance of the head. Magnetic force microscope (MFM) images of the overwrite

  20. Aeroelastic Wing Shaping Using Distributed Propulsion

    Science.gov (United States)

    Nguyen, Nhan T. (Inventor); Reynolds, Kevin Wayne (Inventor); Ting, Eric B. (Inventor)

    2017-01-01

    An aircraft has wings configured to twist during flight. Inboard and outboard propulsion devices, such as turbofans or other propulsors, are connected to each wing, and are spaced along the wing span. A flight controller independently controls thrust of the inboard and outboard propulsion devices to significantly change flight dynamics, including changing thrust of outboard propulsion devices to twist the wing, and to differentially apply thrust on each wing to change yaw and other aspects of the aircraft during various stages of a flight mission. One or more generators can be positioned upon the wing to provide power for propulsion devices on the same wing, and on an opposite wing.

  1. Butterflies regulate wing temperatures using radiative cooling

    Science.gov (United States)

    Tsai, Cheng-Chia; Shi, Norman Nan; Ren, Crystal; Pelaez, Julianne; Bernard, Gary D.; Yu, Nanfang; Pierce, Naomi

    2017-09-01

    Butterfly wings are live organs embedded with multiple sensory neurons and, in some species, with pheromoneproducing cells. The proper function of butterfly wings demands a suitable temperature range, but the wings can overheat quickly in the sun due to their small thermal capacity. We developed an infrared technique to map butterfly wing temperatures and discovered that despite the wings' diverse visible colors, regions of wings that contain live cells are the coolest, resulting from the thickness of the wings and scale nanostructures. We also demonstrated that butterflies use behavioral traits to prevent overheating of their wings.

  2. Asymmetry and coherence weight of quantum states

    Science.gov (United States)

    Bu, Kaifeng; Anand, Namit; Singh, Uttam

    2018-03-01

    The asymmetry of quantum states is an important resource in quantum information processing tasks such as quantum metrology and quantum communication. In this paper, we introduce the notion of asymmetry weight—an operationally motivated asymmetry quantifier in the resource theory of asymmetry. We study the convexity and monotonicity properties of asymmetry weight and focus on its interplay with the corresponding semidefinite programming (SDP) forms along with its connection to other asymmetry measures. Since the SDP form of asymmetry weight is closely related to asymmetry witnesses, we find that the asymmetry weight can be regarded as a (state-dependent) asymmetry witness. Moreover, some specific entanglement witnesses can be viewed as a special case of an asymmetry witness—which indicates a potential connection between asymmetry and entanglement. We also provide an operationally meaningful coherence measure, which we term coherence weight, and investigate its relationship to other coherence measures like the robustness of coherence and the l1 norm of coherence. In particular, we show that for Werner states in any dimension d all three coherence quantifiers, namely, the coherence weight, the robustness of coherence, and the l1 norm of coherence, are equal and are given by a single letter formula.

  3. Asymmetry quantization and application to human mandibles

    DEFF Research Database (Denmark)

    Glerup, Nanna; Nielsen, Mads; Sporring, Jon

    2004-01-01

    All biological objects exhibit some degree of asymmetry, but for some parts of the human body, excessive asymmetry is a sign of pathology. Hence, the problem is to draw the line between categorization of objects being too asymmetric and objects exhibiting normal asymmetry. With a measure of asymm...

  4. Stiffness of desiccating insect wings

    Energy Technology Data Exchange (ETDEWEB)

    Mengesha, T E; Vallance, R R [Department of Mechanical Engineering, The George Washington University, 738 Phillips Hall, 801 22nd St NW, Washington, DC 20052 (United States); Mittal, R, E-mail: vallance@gwu.edu [Department of Mechanical Engineering, Johns Hopkins University, 126 Latrobe Hall, 3400 N Charles Street, Baltimore, MD 21218 (United States)

    2011-03-15

    The stiffness of insect wings is typically determined through experimental measurements. Such experiments are performed on wings removed from insects. However, the wings are subject to desiccation which typically leads to an increase in their stiffness. Although this effect of desiccation is well known, a comprehensive study of the rate of change in stiffness of desiccating insect wings would be a significant aid in planning experiments as well as interpreting data from such experiments. This communication presents a comprehensive experimental analysis of the change in mass and stiffness of gradually desiccating forewings of Painted Lady butterflies (Vanessa cardui). Mass and stiffness of the forewings of five butterflies were simultaneously measured every 10 min over a 24 h period. The averaged results show that wing mass declined exponentially by 21.1% over this time period with a time constant of 9.8 h, while wing stiffness increased linearly by 46.2% at a rate of 23.4 {mu}N mm{sup -1} h{sup -1}. For the forewings of a single butterfly, the experiment was performed over a period of 1 week, and the results show that wing mass declined exponentially by 52.2% with a time constant of 30.2 h until it reached a steady-state level of 2.00 mg, while wing stiffness increased exponentially by 90.7% until it reached a steady-state level of 1.70 mN mm{sup -1}. (communication)

  5. AERODYNAMICS OF WING TIP SAILS

    Directory of Open Access Journals (Sweden)

    MUSHTAK AL-ATABI

    2006-06-01

    Full Text Available Observers have always been fascinated by soaring birds. An interesting feature of these birds is the existence of few feathers extending from the tip of the wing. In this paper, small lifting surfaces were fitted to the tip of a NACA0012 wing in a fashion similar to that of wing tip feathers. Experimental measurements of induced drag, longitudinal static stability and trailing vortex structure were obtained.The tests showed that adding wing tip surfaces (sails decreased the induced drag factor and increased the longitudinal static stability. Results identified two discrete appositely rotated tip vortices and showed the ability of wing tip surfaces to break them down and to diffuse them.

  6. Asymmetry in serial femtosecond crystallography data.

    Science.gov (United States)

    Sharma, Amit; Johansson, Linda; Dunevall, Elin; Wahlgren, Weixiao Y; Neutze, Richard; Katona, Gergely

    2017-03-01

    Serial crystallography is an increasingly important approach to protein crystallography that exploits both X-ray free-electron laser (XFEL) and synchrotron radiation. Serial crystallography recovers complete X-ray diffraction data by processing and merging diffraction images from thousands of randomly oriented non-uniform microcrystals, of which all observations are partial Bragg reflections. Random fluctuations in the XFEL pulse energy spectrum, variations in the size and shape of microcrystals, integrating over millions of weak partial observations and instabilities in the XFEL beam position lead to new types of experimental errors. The quality of Bragg intensity estimates deriving from serial crystallography is therefore contingent upon assumptions made while modeling these data. Here it is observed that serial femtosecond crystallography (SFX) Bragg reflections do not follow a unimodal Gaussian distribution and it is recommended that an idealized assumption of single Gaussian peak profiles be relaxed to incorporate apparent asymmetries when processing SFX data. The phenomenon is illustrated by re-analyzing data collected from microcrystals of the Blastochloris viridis photosynthetic reaction center and comparing these intensity observations with conventional synchrotron data. The results show that skewness in the SFX observations captures the essence of the Wilson plot and an empirical treatment is suggested that can help to separate the diffraction Bragg intensity from the background.

  7. Analysis of Asymmetric Aircraft Aerodynamics Due to an Experimental Wing Glove

    Science.gov (United States)

    Hartshorn, Fletcher

    2011-01-01

    Aerodynamic analysis on a business jet with a wing glove attached to one wing is presented and discussed. If a wing glove is placed over a portion of one wing, there will be asymmetries in the aircraft as well as overall changes in the forces and moments acting on the aircraft. These changes, referred to as deltas, need to be determined and quantified to make sure the wing glove does not have a drastic effect on the aircraft flight characteristics. TRANAIR, a non-linear full potential solver was used to analyze a full aircraft, with and without a glove, at a variety of flight conditions and angles of attack and sideslip. Changes in the aircraft lift, drag and side force, along with roll, pitch and yawing moment are presented. Span lift and moment distributions are also presented for a more detailed look at the effects of the glove on the aircraft. Aerodynamic flow phenomena due to the addition of the glove and its fairing are discussed. Results show that the glove used here does not present a drastic change in forces and moments on the aircraft, but an added torsional moment around the quarter-chord of the wing may be a cause for some structural concerns.

  8. Explaining the trend in extreme right-wing voting: Germany 1989-1998

    NARCIS (Netherlands)

    Lubbers, M.; Scheepers, P.L.H.

    2001-01-01

    Support for German extreme right-wing parties fluctuated strongly in the 1990s, reaching its highest level of 8.7 per cent in September 1992. Support for these parties also varied between regions. In this paper, we attempt to explain this variation over time and region using individual and

  9. Primary tooth size asymmetry in twins and singletons.

    Science.gov (United States)

    Heikkinen, T; Harila, V; Ollikkala, A; Alvesalo, L

    2016-08-01

    To explore asymmetry values of antimeric deciduous tooth crown dimensions in three types of twins: monozygotic (MZ), dizygotic same-sex (DZ) and opposite-sex (OS) vs. single-born controls. Mesiodistal and labio-lingual crown dimensions of second deciduous molars and mesiodistal canine and first molar crown dimensions of 2159 children at 6-12 years of age were evaluated, originating from the US cross-sectional Collaborative Perinatal Study from the 1970s, including altogether MZ (n = 28), DZ same-sex (n = 33) and OS (n = 39) pairs. Single born (n = 1959) were used as controls. Dental casts were measured for comparison of variance relationships calculated from antimeric teeth, exhibiting fluctuating (FA), and directional (DA) asymmetry using anova. Significant differences appeared in MZ and OS girls in DA of deciduous canines, which gain size in the first and second trimester, and deciduous second molars, which finally stop crown growth during the early post-natal period. Significantly, increased FA values appeared for lower deciduous canines and second molars, indicating greatest environmental stress in OS girls, MZ girls and DZ boys. Twin girls had more fluctuating and directional crown asymmetry than twin boys, but in some dimensions, the twins were more symmetric than controls. Transmembrane hormonal influence between opposite-sex twins, and late gestational stress factors, caused by placental malfunction and/or monochorionicity, may be involved in asymmetric growth of antimers, during critical periods of crown size gain. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Knowledge asymmetries about product "goodness"

    DEFF Research Database (Denmark)

    Kampf, Constance

    agencies, the companies themselves and scientific research.  The purpose of the Ipod application Good GuideTM is to offer consumers a tool for mediating knowledge asymmetries about the products from multiple perspectives.  In light of this new technology, this paper argues for a shift from the notion......, Goodguide.com, uses an IpodTM application to inform consumers about product ratings from individual health, social and environmental perspectives.  This application gathers data from corporations on their product ingredients, and use organizational rating systems based on information from U.S. Federal...... of institutionalization of CSR as a company-focused model (Schultz & Wehmeier 2010) to a focus on inter-institutional and institution-consumer knowledge asymmetries affecting consumer sensemaking practices in purchasing.  Data from the Good GuideTM Ipod application, YouTube Videos about a legal controversy involving...

  11. Quantum fluctuations and inflation

    International Nuclear Information System (INIS)

    Bardeen, J.M.; Bublik, G.J.

    1987-01-01

    The authors study the effect of quantum fluctuations on the roll-down rate of the inflation field in a semiclassical approximation; this is done by treating the inflation field as a classical random field. The quantum fluctuations are simulated by a noise term in the equation of motion. Two different inflationary scenarios (new and chaotic inflation) are considered and it is found that the roll-down rate of the median value of the inflation field is increased by the quantum fluctuations. Non-linear effects may become important in the later stages of the inflationary regime. (author)

  12. Audiometric asymmetry and tinnitus laterality.

    Science.gov (United States)

    Tsai, Betty S; Sweetow, Robert W; Cheung, Steven W

    2012-05-01

    To identify an optimal audiometric asymmetry index for predicting tinnitus laterality. Retrospective medical record review. Data from adult tinnitus patients (80 men and 44 women) were extracted for demographic, audiometric, tinnitus laterality, and related information. The main measures were sensitivity, specificity, positive predictive value (PPV), and receiver operating characteristic (ROC) curves. Three audiometric asymmetry indices were constructed using one, two, or three frequency elements to compute the average interaural threshold difference (aITD). Tinnitus laterality predictive performance of a particular index was assessed by increasing the cutoff or minimum magnitude of the aITD from 10 to 35 dB in 5-dB steps to determine its ROC curve. Single frequency index performance was inferior to the other two (P .05). Two adjoining frequency elements with aITD ≥ 15 dB performed optimally for predicting tinnitus laterality (sensitivity = 0.59, specificity = 0.71, and PPV = 0.76). Absolute and relative magnitudes of hearing loss in the poorer ear were uncorrelated with tinnitus distress. An optimal audiometric asymmetry index to predict tinnitus laterality is one whereby 15 dB is the minimum aITD of two adjoining frequencies, inclusive of the maximal ITD. Tinnitus laterality dependency on magnitude of interaural asymmetry may inform design and interpretation of neuroimaging studies. Monaural acoustic tinnitus therapy may be an initial consideration for asymmetric hearing loss meeting the criterion of aITD ≥ 15 dB. Copyright © 2012 The American Laryngological, Rhinological, and Otological Society, Inc.

  13. Asymmetry Reduction Theory of FDI

    DEFF Research Database (Denmark)

    Li, Xin

    In this paper, I first briefly introduce Moon & Roehl’s (1993, 2001) imbalance theory of FDI, then I identify its three deficiencies that may be responsible for the relative lack of impact of the potentially powerful imbalance logic, and then I propose an asymmetry reduction theory (ARC) of FDI...... and explain its aspiration-resource-control (ARC) framework. I conclude the paper with a brief discussion of the OLI framework being a special case of the ARC framework....

  14. INFORMATION ASYMMETRY AND HERDING BEHAVIOR

    Directory of Open Access Journals (Sweden)

    Puput Tri Komalasari

    2016-06-01

    Full Text Available Conceptually, the stock market is strong form efficient in the long term. However, in practice, there are various forms of market anomalies that undermine the accuracy of the efficient market hypothesis. One factor suspected as the cause of market inefficiency is herding behavior. Investors herd when they imitate the actions of other investors. This behavior occurs when there is a continuous interaction among rational investors that prevents them from seeking information about market fundamentals. This study provides new insights by including information asymmetry as a moderating variable. This research examines the phenomenon of herding behavior in the Indonesia Stock Exchange as well as examines directly the effect of information asymmetry on herding behavior. The period of study is 2008 using time series of daily stocks data that actively traded in the capital market. Results of this study find that investor tends to follow market consensus when price changes at the low level, but when there is large price swing market participant acts independently from other investors. Interestingly, this study finds that information asymmetry is a necessary condition for the existence of herding behavior.

  15. Structural Analysis of a Dragonfly Wing

    NARCIS (Netherlands)

    Jongerius, S.R.; Lentink, D.

    2010-01-01

    Dragonfly wings are highly corrugated, which increases the stiffness and strength of the wing significantly, and results in a lightweight structure with good aerodynamic performance. How insect wings carry aerodynamic and inertial loads, and how the resonant frequency of the flapping wings is tuned

  16. Modification of Otolith Reflex Asymmetries Following Space Flight

    Science.gov (United States)

    Clarke, Andrew H.; Schoenfeld, Uwe; Wood, Scott J.

    2011-01-01

    We hypothesize that changes in otolith-mediated reflexes adapted for microgravity contribute to perceptual, gaze and postural disturbances upon return to Earth s gravity. Our goal was to determine pre- versus post-fight differences in unilateral otolith reflexes that reflect these adaptive changes. This study represents the first comprehensive examination of unilateral otolith function following space flight. Ten astronauts participated in unilateral otolith function tests three times pre-flight and up to four times after Shuttle flights from landing day through the subsequent 10 days. During unilateral centrifugation (UC, +/- 3.5cm at 400deg/s), utricular function was examined by the perceptual changes reflected by the subjective visual vertical (SVV) and by video-oculographic measurement of the otolith-mediated ocular counter-roll (OOR). Unilateral saccular reflexes were recorded by measurement of collic Vestibular Evoked Myogenic Potential (cVEMP). Although data from a few subjects were not obtained early post-flight, a general increase in asymmetry of otolith responses was observed on landing day relative to pre-flight baseline, with a subsequent reversal in asymmetry within 2-3 days. Recovery to baseline levels was achieved within 10 days. This fluctuation in the asymmetry measures appeared strongest for SVV, in a consistent direction for OOR, and in an opposite direction for cVEMP. These results are consistent with our hypothesis that space flight results in adaptive changes in central nervous system processing of otolith input. Adaptation to microgravity may reveal asymmetries in otolith function upon to return to Earth that were not detected prior to the flight due to compensatory mechanisms.

  17. Feedback tracking control for dynamic morphing of piezocomposite actuated flexible wings

    Science.gov (United States)

    Wang, Xiaoming; Zhou, Wenya; Wu, Zhigang

    2018-03-01

    Aerodynamic properties of flexible wings can be improved via shape morphing using piezocomposite materials. Dynamic shape control of flexible wings is investigated in this study by considering the interactions between structural dynamics, unsteady aerodynamics and piezo-actuations. A novel antisymmetric angle-ply bimorph configuration of piezocomposite actuators is presented to realize coupled bending-torsional shape control. The active aeroelastic model is derived using finite element method and Theodorsen unsteady aerodynamic loads. A time-varying linear quadratic Gaussian (LQG) tracking control system is designed to enhance aerodynamic lift with pre-defined trajectories. Proof-of-concept simulations of static and dynamic shape control are presented for a scaled high-aspect-ratio wing model. Vibrations of the wing and fluctuations in aerodynamic forces are caused by using the static voltages directly in dynamic shape control. The lift response has tracked the trajectories well with favorable dynamic morphing performance via feedback tracking control.

  18. Effect of outer wing separation on lift and thrust generation in a flapping wing system

    International Nuclear Information System (INIS)

    Mahardika, Nanang; Viet, Nguyen Quoc; Park, Hoon Cheol

    2011-01-01

    We explore the implementation of wing feather separation and lead-lagging motion to a flapping wing. A biomimetic flapping wing system with separated outer wings is designed and demonstrated. The artificial wing feather separation is implemented in the biomimetic wing by dividing the wing into inner and outer wings. The features of flapping, lead-lagging, and outer wing separation of the flapping wing system are captured by a high-speed camera for evaluation. The performance of the flapping wing system with separated outer wings is compared to that of a flapping wing system with closed outer wings in terms of forward force and downward force production. For a low flapping frequency ranging from 2.47 to 3.90 Hz, the proposed biomimetic flapping wing system shows a higher thrust and lift generation capability as demonstrated by a series of experiments. For 1.6 V application (lower frequency operation), the flapping wing system with separated wings could generate about 56% higher forward force and about 61% less downward force compared to that with closed wings, which is enough to demonstrate larger thrust and lift production capability of the separated outer wings. The experiments show that the outer parts of the separated wings are able to deform, resulting in a smaller amount of drag production during the upstroke, while still producing relatively greater lift and thrust during the downstroke.

  19. Flapping Wing Micro Air Vehicle Wing Manufacture and Force Testing

    Science.gov (United States)

    2011-03-03

    manufacturing techniques have been developed by various universities for research on Flapping Wing Micro Air Vehicles. Minimal attention though is given...collected at 2kHz (www.polytec.com/psv3d). A 0.25V band-limited white noise input signal is input to a Bogen HTA -125 High Performance Amplifier, which...manufacturing techniques have been developed by various universities for research on Flapping Wing Micro Air Vehicles. Minimal attention though is given

  20. Fully Quantum Fluctuation Theorems

    Science.gov (United States)

    Åberg, Johan

    2018-02-01

    Systems that are driven out of thermal equilibrium typically dissipate random quantities of energy on microscopic scales. Crooks fluctuation theorem relates the distribution of these random work costs to the corresponding distribution for the reverse process. By an analysis that explicitly incorporates the energy reservoir that donates the energy and the control system that implements the dynamic, we obtain a quantum generalization of Crooks theorem that not only includes the energy changes in the reservoir but also the full description of its evolution, including coherences. Moreover, this approach opens up the possibility for generalizations of the concept of fluctuation relations. Here, we introduce "conditional" fluctuation relations that are applicable to nonequilibrium systems, as well as approximate fluctuation relations that allow for the analysis of autonomous evolution generated by global time-independent Hamiltonians. We furthermore extend these notions to Markovian master equations, implicitly modeling the influence of the heat bath.

  1. Fully Quantum Fluctuation Theorems

    Directory of Open Access Journals (Sweden)

    Johan Åberg

    2018-02-01

    Full Text Available Systems that are driven out of thermal equilibrium typically dissipate random quantities of energy on microscopic scales. Crooks fluctuation theorem relates the distribution of these random work costs to the corresponding distribution for the reverse process. By an analysis that explicitly incorporates the energy reservoir that donates the energy and the control system that implements the dynamic, we obtain a quantum generalization of Crooks theorem that not only includes the energy changes in the reservoir but also the full description of its evolution, including coherences. Moreover, this approach opens up the possibility for generalizations of the concept of fluctuation relations. Here, we introduce “conditional” fluctuation relations that are applicable to nonequilibrium systems, as well as approximate fluctuation relations that allow for the analysis of autonomous evolution generated by global time-independent Hamiltonians. We furthermore extend these notions to Markovian master equations, implicitly modeling the influence of the heat bath.

  2. Fishing and stock fluctuations

    National Research Council Canada - National Science Library

    Laevastu, Taivo; Favorite, F

    1988-01-01

    .... Scarcely publicized are the multitude of causes of fish stock fluctuations. This book attempts to summarize the available knowledge on the subject and includes original work of the authors on a matter vital to the fisheries industries of the world...

  3. Scaling metabolic rate fluctuations

    OpenAIRE

    Labra, Fabio A.; Marquet, Pablo A.; Bozinovic, Francisco

    2007-01-01

    Complex ecological and economic systems show fluctuations in macroscopic quantities such as exchange rates, size of companies or populations that follow non-Gaussian tent-shaped probability distributions of growth rates with power-law decay, which suggests that fluctuations in complex systems may be governed by universal mechanisms, independent of particular details and idiosyncrasies. We propose here that metabolic rate within individual organisms may be considered as an example of an emerge...

  4. Research of Morphing Wing Efficiency

    National Research Council Canada - National Science Library

    Komarov, Valery

    2004-01-01

    This report results from a contract tasking Samara State Aerospace University (SSAU) as follows: The contractor will develop and investigate aerodynamic and structural weight theories associated with morphing wing technology...

  5. Drag Performance of Twist Morphing MAV Wing

    Directory of Open Access Journals (Sweden)

    Ismail N.I.

    2016-01-01

    Full Text Available Morphing wing is one of latest evolution found on MAV wing. However, due to few design problems such as limited MAV wing size and complicated morphing mechanism, the understanding of its aerodynamic behaviour was not fully explored. In fact, the basic drag distribution induced by a morphing MAV wing is still remained unknown. Thus, present work is carried out to compare the drag performance between a twist morphing wing with membrane and rigid MAV wing design. A quasi-static aeroelastic analysis by using the Ansys-Fluid Structure Interaction (FSI method is utilized in current works to predict the drag performance a twist morphing MAV wing design. Based on the drag pattern study, the results exhibits that the morphing wing has a partial similarities in overall drag pattern with the baseline (membrane and rigid wing. However, based CD analysis, it shows that TM wing induced higher CD magnitude (between 25% to 82% higher than to the baseline wing. In fact, TM wing also induced the largest CD increment (about 20% to 27% among the wings. The visualization on vortex structure revealed that TM wing also produce larger tip vortex structure (compared to baseline wings which presume to promote higher induce drag component and subsequently induce its higher CD performance.

  6. Inheritance of dermatoglyphic asymmetry in 500 Indian pedigrees: complex segregation analysis.

    Science.gov (United States)

    Karmakar, Bibha; Malkin, Ida; Kobyliansky, Eugene

    2012-03-01

    The major aim of this study is to determine the mode of inheritance of asymmetry of quantitative dermatoglyphic traits based on principal factors through the application of complex segregation (genetic model fitting) analyses on a large ethnically homogeneous sample of 500 Indian pedigrees (2435 individuals) of two generations. By segregation analysis of the traits- PC1_FA both Mendelian and Environmental models were rejected (< 0.001) with the General model, i.e. that despite presence of significant inheritance (rejection of Environmental model), the nature of inheritance is more complex, than Mendelian one. Although a little genetic effect was observed due to familial correlations on asymmetry traits, no evidence was found of major gene contribution to be involved, but this does not contradict the notion postulated by several earlier authors that asymmetry (fluctuating) provides a measure of developmental instability in human.

  7. Directional asymmetry estimates developmental instability in plants: A case report in Plantago major L. leaves

    Directory of Open Access Journals (Sweden)

    Veličković Miroslava V.

    2006-01-01

    Full Text Available In the present study, an additional approach was used to evaluate the potential effects of the industrial development on natural population of the common plantain (Plantago major L., previously estimated using si2 as an index of fluctuation asymmetry (FA together with the coefficient of variation (CV. In this study, directional asymmetry (DA, a form of asymmetry in bilaterally symmetric traits, was used in order to estimate its rule as a potential indicator of developmental instability in leaf traits. Obtained results shows significantly higher DA values for the vein distances within a leaf (VD on environmentally stressed area than in the control site. Reporting significantly higher values of DA for VD on the environmentally stressed sample and a positive relationship between FA and CV values obtained for the same trait within the same site, in a previous study, the study corroborates the potential of DA as an indicator of developmental perturbations.

  8. Core and Wing Densities of Asymmetric Coronal Spectral Profiles: Implications for the Mass Supply of the Solar Corona

    Science.gov (United States)

    Patsourakos, S.; Klimchuk, J. A.; Young, P. R.

    2014-01-01

    Recent solar spectroscopic observations have shown that coronal spectral lines can exhibit asymmetric profiles, with enhanced emissions at their blue wings. These asymmetries correspond to rapidly upflowing plasmas at speeds exceeding approximately equal to 50 km per sec. Here, we perform a study of the density of the rapidly upflowing material and compare it with that of the line core that corresponds to the bulk of the plasma. For this task, we use spectroscopic observations of several active regions taken by the Extreme Ultraviolet Imaging Spectrometer of the Hinode mission. The density sensitive ratio of the Fe(sub XIV) lines at 264.78 and 274.20 Angstroms is used to determine wing and core densities.We compute the ratio of the blue wing density to the core density and find that most values are of order unity. This is consistent with the predictions for coronal nanoflares if most of the observed coronal mass is supplied by chromospheric evaporation driven by the nanoflares. However, much larger blue wing-to-core density ratios are predicted if most of the coronal mass is supplied by heated material ejected with type II spicules. Our measurements do not rule out a spicule origin for the blue wing emission, but they argue against spicules being a primary source of the hot plasma in the corona. We note that only about 40% of the pixels where line blends could be safely ignored have blue wing asymmetries in both Fe(sub XIV) lines. Anticipated sub-arcsecond spatial resolution spectroscopic observations in future missions could shed more light on the origin of blue, red, and mixed asymmetries.

  9. The origin of density fluctuations in the 'new inflationary universe'

    Science.gov (United States)

    Turner, M. S.

    1983-01-01

    Cosmological mysteries which are not explained by the Big Bang hypothesis but may be approached by a revamped inflationary universe model are discussed. Attention is focused on the isotropy, the large-scale homogeneity, small-scale inhomogeneity, the oldness/flatness of the universe, and the baryon asymmetry. The universe is assumed to start in the lowest energy state, be initially dominated by false vacuum energy, enter a de Sitter phase, and then cross a barrier which is followed by the formation of fluctuation regions that lead to structure. The scalar fields (perturbation regions) experience quantum fluctuations which produce spontaneous symmetry breaking on a large scale. The scalar field value would need to be much greater than the expansion rate during the de Sitter epoch. A supersymmetric (flat) potential which satisfies the requirement, yields fluctuations of the right magnitude, and allows inflation to occur is described.

  10. Modification of boundary fluctuations by LHCD in the HT-7 tokamak

    International Nuclear Information System (INIS)

    Song Mei; Wan Baonian; Xu Guosheng; Ling Bili

    2003-01-01

    Measurements of boundary fluctuations and fluctuation driven electron fluxes have been performed in ohmic and lower hybrid current drive enhanced confinement plasma using a graphite Langmuir probe array on HT-7 tokamak. The fluctuations are significantly suppressed and the turbulent fluxes are remarkably depressed in the enhanced plasma. We characterized the statistical properties of fluctuations and the particle flux and found a non-Gaussian character in the whole scrape-off layer with minimum deviations from Gaussian in the proximity of the velocity shear layer in ohmic plasma. In the enhanced plasma the deviations in the boundary region are all reduces obviously. The fluctuations and induced electron fluxes show sporadic bursts asymmetric in time and the asymmetry is remarkably weakened in the lower hybrid current driving (LHCD) phase. The results suggest a coupling between the statistical behaviour of fluctuations and the turbulent flow

  11. Breast asymmetry and predisposition to breast cancer

    OpenAIRE

    Scutt, Diane; Lancaster, Gillian A; Manning, John T

    2006-01-01

    INTRODUCTION: It has been shown in our previous work that breast asymmetry is related to several of the known risk factors for breast cancer, and that patients with diagnosed breast cancer have more breast volume asymmetry, as measured from mammograms, than age-matched healthy women. METHODS: In the present study, we compared the breast asymmetry of women who were free of breast disease at time of mammography, but who had subsequently developed breast cancer, with that of age-matched healthy ...

  12. Write field asymmetry in perpendicular magnetic recording

    Science.gov (United States)

    Li, Zhanjie; Bai, Daniel Z.; Lin, Ed; Mao, Sining

    2012-04-01

    We present a systematic study of write field asymmetry by using micromagnetic modeling for a perpendicular magnetic recording (PMR) writer structure. Parameters investigated include initial magnetization condition, write current amplitude, write current frequency, and initial write current polarity. It is found that the write current amplitude and frequency (data rate) are the dominant factors that impact the field asymmetry. Lower write current amplitude and higher write current frequency will deteriorate the write field asymmetry, causing recording performance (such as bit error rate) degradation.

  13. A New Operative One-Wing Technique to Correct Fronto-Orbital Region in Unilateral Nonsyndromic Plagiocephaly.

    Science.gov (United States)

    Messi, Marco; Luzi, Michele; Consorti, Giuseppe

    2018-01-01

    Anterior plagiocephaly is a premature closing of unilateral coronal suture. This premature suture fusion causes a series of cranial asymmetry and alteration of the fronto-orbital region.The authors described a new surgical technique to correct the facial asymmetry that reduces the operative time and the possible complications.In a period between 2013and 2016, 12 children affected by nonsyndromic anterior plagiocephaly were treated with this new procedure.Clinical, cranial development, and absence of postoperative complication demonstrated that one-wing surgical bone correction is a useful and innovative technique.

  14. In-flight total forces, moments and static aeroelastic characteristics of an oblique-wing research airplane

    Science.gov (United States)

    Curry, R. E.; Sim, A. G.

    1984-01-01

    A low-speed flight investigation has provided total force and moment coefficients and aeroelastic effects for the AD-1 oblique-wing research airplane. The results were interpreted and compared with predictions that were based on wind tunnel data. An assessment has been made of the aeroelastic wing bending design criteria. Lateral-directional trim requirements caused by asymmetry were determined. At angles of attack near stall, flow visualization indicated viscous flow separation and spanwise vortex flow. These effects were also apparent in the force and moment data.

  15. Single spin asymmetry for charm mesons

    Energy Technology Data Exchange (ETDEWEB)

    Dominguez Zacarias, G. [PIMAyC, Eje Central Lazaro Cardenas No. 152, Apdo. Postal 14-805, D.F. (Mexico); Herrera, G.; Mercado, J. [Centro de Investigacion y de Estudios Avanzados, Apdo. Postal 14-740, D.F. (Mexico)

    2007-08-15

    We study single spin asymmetries of D{sup 0} and D{sup -} mesons in polarized proton-proton collisions. A two component model is used to describe charm meson production. The production of D mesons occurs by recombination of the constituents present in the initial state as well as by fragmentation of quarks in the final state. This model has proved to describe the production of charm. The recombination component involves a mechanism of spin alignment that ends up in a single spin asymmetry. Experimental measurements of single spin asymmetry for pions at RHIC are compared with the model. Predictions for the asymmetry in D mesons are presented. (orig.)

  16. Single spin asymmetry for charm mesons

    International Nuclear Information System (INIS)

    Dominguez Zacarias, G.; Herrera, G.; Mercado, J.

    2007-01-01

    We study single spin asymmetries of D 0 and D - mesons in polarized proton-proton collisions. A two component model is used to describe charm meson production. The production of D mesons occurs by recombination of the constituents present in the initial state as well as by fragmentation of quarks in the final state. This model has proved to describe the production of charm. The recombination component involves a mechanism of spin alignment that ends up in a single spin asymmetry. Experimental measurements of single spin asymmetry for pions at RHIC are compared with the model. Predictions for the asymmetry in D mesons are presented. (orig.)

  17. Universal mesoscopic conductance fluctuations

    International Nuclear Information System (INIS)

    Evangelou, S.N.

    1992-01-01

    The theory of conductance fluctuations in disordered metallic systems with size large compared to the mean free path of the electron but small compared to localization length is considered. It is demonstrates that fluctuations have an universal character and are due to repulsion between levels and spectral rigidity. The basic fluctuation measures for the energy spectrum in the mesoscopic regime of disordered systems are consistent with the Gaussian random matrix ensemble predictions. Although our disordered electron random matrix ensemble does not belong to the Gaussian ensemble the two ensembles turn out to be essentially similar. The level repulsion and the spectral rigidity found in nuclear spectra should also be observed in the metallic regime of Anderson localization. 7 refs. (orig.)

  18. Spin fluctuations and the

    Directory of Open Access Journals (Sweden)

    V.M. Loktev

    2008-09-01

    Full Text Available We analyze the spectral properties of a phenomenological model for a weakly doped two-dimensional antiferromagnet, in which the carriers move within one of the two sublattices where they were introduced. Such a constraint results in the free carrier spectra with the maxima at k=(± π/2 , ± π/2 observed in some cuprates. We consider the spectral properties of the model by taking into account fluctuations of the spins in the antiferromagnetic background. We show that such fluctuations lead to a non-pole-like structure of the single-hole Green's function and these fluctuations can be responsible for some anomalous "strange metal" properties of underdoped cuprates in the nonsuperconducting regime.

  19. Evaluating asymmetry in prosthetic gait with step-length asymmetry alone is flawed

    NARCIS (Netherlands)

    Roerdink, M.; Roeles, S.; van der Pas, S.C.H.; Bosboom, O.; Beek, P.J.

    2012-01-01

    Prosthetic gait is often asymmetric in step length, but the direction of this asymmetry varies inconsistently across amputees. This situation is akin to that seen in stroke patients, where step-length asymmetry has been shown to be the additive result of asymmetries in trunk progression and

  20. The fluctuating gap model

    International Nuclear Information System (INIS)

    Cao, Xiaobin

    2011-01-01

    The quasi-one-dimensional systems exhibit some unusual phenomenon, such as the Peierls instability, the pseudogap phenomena and the absence of a Fermi-Dirac distribution function line shape in the photoemission spectroscopy. Ever since the discovery of materials with highly anisotropic properties, it has been recognized that fluctuations play an important role above the three-dimensional phase transition. This regime where the precursor fluctuations are presented can be described by the so called fluctuating gap model (FGM) which was derived from the Froehlich Hamiltonian to study the low energy physics of the one-dimensional electron-phonon system. Not only is the FGM of great interest in the context of quasi-one-dimensional materials, liquid metal and spin waves above T c in ferromagnets, but also in the semiclassical approximation of superconductivity, it is possible to replace the original three-dimensional problem by a directional average over effectively one-dimensional problem which in the weak coupling limit is described by the FGM. In this work, we investigate the FGM in a wide temperature range with different statistics of the order parameter fluctuations. We derive a formally exact solution to this problem and calculate the density of states, the spectral function and the optical conductivity. In our calculation, we show that a Dyson singularity appears in the low energy density of states for Gaussian fluctuations in the commensurate case. In the incommensurate case, there is no such kind of singularity, and the zero frequency density of states varies differently as a function of the correlation lengths for different statistics of the order parameter fluctuations. Using the density of states we calculated with non-Gaussian order parameter fluctuations, we are able to calculate the static spin susceptibility which agrees with the experimental data very well. In the calculation of the spectral functions, we show that as the correlation increases, the quasi

  1. The fluctuating gap model

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Xiaobin

    2011-01-15

    The quasi-one-dimensional systems exhibit some unusual phenomenon, such as the Peierls instability, the pseudogap phenomena and the absence of a Fermi-Dirac distribution function line shape in the photoemission spectroscopy. Ever since the discovery of materials with highly anisotropic properties, it has been recognized that fluctuations play an important role above the three-dimensional phase transition. This regime where the precursor fluctuations are presented can be described by the so called fluctuating gap model (FGM) which was derived from the Froehlich Hamiltonian to study the low energy physics of the one-dimensional electron-phonon system. Not only is the FGM of great interest in the context of quasi-one-dimensional materials, liquid metal and spin waves above T{sub c} in ferromagnets, but also in the semiclassical approximation of superconductivity, it is possible to replace the original three-dimensional problem by a directional average over effectively one-dimensional problem which in the weak coupling limit is described by the FGM. In this work, we investigate the FGM in a wide temperature range with different statistics of the order parameter fluctuations. We derive a formally exact solution to this problem and calculate the density of states, the spectral function and the optical conductivity. In our calculation, we show that a Dyson singularity appears in the low energy density of states for Gaussian fluctuations in the commensurate case. In the incommensurate case, there is no such kind of singularity, and the zero frequency density of states varies differently as a function of the correlation lengths for different statistics of the order parameter fluctuations. Using the density of states we calculated with non-Gaussian order parameter fluctuations, we are able to calculate the static spin susceptibility which agrees with the experimental data very well. In the calculation of the spectral functions, we show that as the correlation increases, the

  2. Niche suitability affects development: skull asymmetry increases in less suitable areas.

    Directory of Open Access Journals (Sweden)

    Renan Maestri

    Full Text Available For conservation purposes, it is important to take into account the suitability of a species to particular habitats; this information may predict the long-term survival of a species. In this sense, morphological measures of developmental stress, such as fluctuating asymmetry, can be proxies for an individual's performance in different regions. In this study, we conducted tests to determine whether areas with different levels of suitability for a species (generated by ecological niche models were congruent with morphological markers that reflect environmental stress and morphological variance. We generated a Maxent niche model and compared the suitability assessments of several areas with the skull morphology data (fluctuating asymmetry and morphological disparity of populations of the Atlantic forest endemic to Brazil rodent Akodon cursor. Our analyses showed a significant negative relationship between suitability levels and fluctuating asymmetry levels, which indicates that in less suitable areas, the individuals experience numerous disturbances during skull ontogeny. We have not found an association between morphological variance and environmental suitability. As expected, these results suggest that in environments with a lower suitability, developmental stress is increased. Such information is helpful in the understanding of the species evolution and in the selection of priority areas for the conservation of species.

  3. Recent HERMES Results on DVCS Associated Asymmetries

    Science.gov (United States)

    Shanidze, R.

    2002-11-01

    The latest HERMES measurements of the beam--spin and beam--charge azimuthal asymmetries in the hard exclusive electroproduction of photons are reported. The asymmetries are associated with the Deeply Virtual Compton Scattering (DVCS) process and can provide new information on the structure of the nucleon.

  4. The Hemispheric Asymmetry of Polar Faculae

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... In this paper, the north–south (N–S) asymmetry of the polar faculae at relatively low (RLLs), relatively high (RHLs) as well as total latitudes (TLs) respectively, are investigated. It is found that. the polar faculae behave in a different asymmetrical way at different latitudinal bands;; the asymmetry of solar activity ...

  5. Terrestrial Gravity Fluctuations

    Directory of Open Access Journals (Sweden)

    Jan Harms

    2015-12-01

    Full Text Available Different forms of fluctuations of the terrestrial gravity field are observed by gravity experiments. For example, atmospheric pressure fluctuations generate a gravity-noise foreground in measurements with super-conducting gravimeters. Gravity changes caused by high-magnitude earthquakes have been detected with the satellite gravity experiment GRACE, and we expect high-frequency terrestrial gravity fluctuations produced by ambient seismic fields to limit the sensitivity of ground-based gravitational-wave (GW detectors. Accordingly, terrestrial gravity fluctuations are considered noise and signal depending on the experiment. Here, we will focus on ground-based gravimetry. This field is rapidly progressing through the development of GW detectors. The technology is pushed to its current limits in the advanced generation of the LIGO and Virgo detectors, targeting gravity strain sensitivities better than 10^–23 Hz^–1/2 above a few tens of a Hz. Alternative designs for GW detectors evolving from traditional gravity gradiometers such as torsion bars, atom interferometers, and superconducting gradiometers are currently being developed to extend the detection band to frequencies below 1 Hz. The goal of this article is to provide the analytical framework to describe terrestrial gravity perturbations in these experiments. Models of terrestrial gravity perturbations related to seismic fields, atmospheric disturbances, and vibrating, rotating or moving objects, are derived and analyzed. The models are then used to evaluate passive and active gravity noise mitigation strategies in GW detectors, or alternatively, to describe their potential use in geophysics. The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our

  6. Terrestrial Gravity Fluctuations

    Science.gov (United States)

    Harms, Jan

    2015-12-01

    Different forms of fluctuations of the terrestrial gravity field are observed by gravity experiments. For example, atmospheric pressure fluctuations generate a gravity-noise foreground in measurements with super-conducting gravimeters. Gravity changes caused by high-magnitude earthquakes have been detected with the satellite gravity experiment GRACE, and we expect high-frequency terrestrial gravity fluctuations produced by ambient seismic fields to limit the sensitivity of ground-based gravitational-wave (GW) detectors. Accordingly, terrestrial gravity fluctuations are considered noise and signal depending on the experiment. Here, we will focus on ground-based gravimetry. This field is rapidly progressing through the development of GW detectors. The technology is pushed to its current limits in the advanced generation of the LIGO and Virgo detectors, targeting gravity strain sensitivities better than 10-23 Hz-1/2 above a few tens of a Hz. Alternative designs for GW detectors evolving from traditional gravity gradiometers such as torsion bars, atom interferometers, and superconducting gradiometers are currently being developed to extend the detection band to frequencies below 1 Hz. The goal of this article is to provide the analytical framework to describe terrestrial gravity perturbations in these experiments. Models of terrestrial gravity perturbations related to seismic fields, atmospheric disturbances, and vibrating, rotating or moving objects, are derived and analyzed. The models are then used to evaluate passive and active gravity noise mitigation strategies in GW detectors, or alternatively, to describe their potential use in geophysics. The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our understanding of

  7. Multiple photon emission and b quark asymmetries

    International Nuclear Information System (INIS)

    Jadach, S.; Ward, B.F.L.

    1989-08-01

    We discuss the effects of multiple photon final states in high precision tests of the SU 2L x U 1 model wherein one measures the b quark asymmetries at a very high luminosity Z 0 factory, such as the possible high luminosity upgrade of the CERN LEP collider. The specific asymmetries analyzed are the forward-backward asymmetry A FB , the left-right polarized asymmetry A LR and the polarized forward-backward asymmetry A FB,pol. . The radiative effects are found to be significant for A FB as expected, but they are not as large, on a percentage basis, as the corresponding result for muons. (author). 5 refs, 1 tab

  8. Conceptual Study of Rotary-Wing Microrobotics

    National Research Council Canada - National Science Library

    Chabak, Kelson D

    2008-01-01

    This thesis presents a novel rotary-wing micro-electro-mechanical systems (MEMS) robot design. Two MEMS wing designs were designed, fabricated and tested including one that possesses features conducive to insect level aerodynamics...

  9. Aerodynamic control with passively pitching wings

    Science.gov (United States)

    Gravish, Nick; Wood, Robert

    Flapping wings may pitch passively under aerodynamic and inertial loads. Such passive pitching is observed in flapping wing insect and robot flight. The effect of passive wing pitch on the control dynamics of flapping wing flight are unexplored. Here we demonstrate in simulation and experiment the critical role wing pitching plays in yaw control of a flapping wing robot. We study yaw torque generation by a flapping wing allowed to passively rotate in the pitch axis through a rotational spring. Yaw torque is generated through alternating fast and slow upstroke and and downstroke. Yaw torque sensitively depends on both the rotational spring force law and spring stiffness, and at a critical spring stiffness a bifurcation in the yaw torque control relationship occurs. Simulation and experiment reveal the dynamics of this bifurcation and demonstrate that anomalous yaw torque from passively pitching wings is the result of aerodynamic and inertial coupling between the pitching and stroke-plane dynamics.

  10. Bs semileptonic asymmetry at LHCb

    CERN Multimedia

    Dufour, Laurent

    2016-01-01

    When neutral $B^{0}_{s,d}$ mesons evolve in time they can change into their own antiparticles. In this mixing process CP symmetry is not necessarily conserved, as the probability for a $B^{0}$ meson to change into a $\\bar{B}^{0}$ meson can be different from the probability for the reverse process. The CP violation in the $B^{0}_{s}$ system as measured using semileptonic decays, defined as $a^{s}_{sl}$, is very small according to the Standard Model. However, earlier measurements of the semileptonic mixing asymmetry in both the $B_s^{0}$ and $B_d^{0}$ systems have shown a $3 \\sigma$ deviation with respect to the Standard Model value. A measurement of $a^{s}_{sl}$ performed using $1 \\text{fb}^{-1}$ of data collected at the LHCb detector is presented, together with an outlook to the updated $3 \\text{fb}^{-1}$ result.

  11. Waving Wing Aerodynamics at Low Reynolds Numbers

    Science.gov (United States)

    2010-07-01

    wing. An attached leading edge vortex has been observed by multiple research groups on both mechanical wing flappers (8; 22; 21; 4) and revolving wing...observed by Ellington et al. (8) in their earlier experiments on the mechanical hawkmoth flapper at Re ≈ 10,000. In these experiments the spanwise flow...on mechanical wing flappers at similar Reynolds numbers, Re ≈ 1,000 and 1,400 respectively. Both sets of experiments revealed a stable attached

  12. On the leading edge vortex of thin wings

    Science.gov (United States)

    Arredondo, Abel; Viola, Ignazio Maria

    2016-11-01

    On thin wings, the sharp leading edge triggers laminar separation followed by reattachment, forming a Leading Edge Vortex (LEV). This flow feature is of paramount importance because, if periodically shed, it leads to large amplitude load fluctuations, while if stably attached to the wing, it can provide lift augmentation. We found that on asymmetric-spinnaker-type yacht sails, the LEV can be stable despite the relatively low sweep (30°). This finding, which was recently predicted numerically by Viola et al., has been confirmed through current flume tests on a 1:115th model scale sail. Forces were measured and Particle Image Velocimetry was performed on four horizontal sail sections at a Reynolds number of 1.7x104. Vortex detection revealed that the LEV becomes progressively larger and more stable towards the highest sections, where its axis has a smaller angle with respect to the freestream velocity. Mapping the sail section on a rotating cylinder through a Joukowski transformation, we quantified the lift augmentation provided by the LEV on each sail section. These results open up new sail design strategies based on the manipulation of the LEV and can be applicable to the wings of unmanned aerial vehicles and underwater vehicles. Project funded by Conacyt.

  13. Fluctuations in quantum devices

    Directory of Open Access Journals (Sweden)

    H.Haken

    2004-01-01

    Full Text Available Logical gates can be formalized by Boolean algebra whose elementary operations can be realized by devices that employ the interactions of macroscopic numbers of elementary excitations such as electrons, holes, photons etc. With increasing miniaturization to the nano scale and below, quantum fluctuations become important and can no longer be ignored. Based on Heisenberg equations of motion for the creation and annihilation operators of elementary excitations, I determine the noise sources of composite quantum systems.

  14. Physics of fashion fluctuations

    Science.gov (United States)

    Donangelo, R.; Hansen, A.; Sneppen, K.; Souza, S. R.

    2000-12-01

    We consider a market where many agents trade different types of products with each other. We model development of collective modes in this market, and quantify these by fluctuations that scale with time with a Hurst exponent of about 0.7. We demonstrate that individual products in the model occasionally become globally accepted means of exchange, and simultaneously become very actively traded. Thus collective features similar to money spontaneously emerge, without any a priori reason.

  15. Wing area, wing growth and wing loading of common sandpipers Actitis hypoleucos

    OpenAIRE

    Yalden, Derek; Yalden, D. W.

    2012-01-01

    This study investigates the changes in wing length, area and loading in Common Sandpipers as chicks grow, and as adults add extra mass (during egg-laying or before migration). Common Sandpiper chicks weigh about 17 g and have "hands" that are about 35 mm long at one week old, when the primaries are just emerging from their sheaths. They grow steadily to reach about 40 g, with hands about 85 mm long, at 19 days, when they are just about fledging. Their wings have roughly adult chord width at t...

  16. Propulsive force asymmetry during tethered-swimming.

    Science.gov (United States)

    dos Santos, K B; Pereira, G; Papoti, M; Bento, P C B; Rodacki, A

    2013-07-01

    This study aimed to determine whether: i) tethe-red-swimming can be used to identify the asymmetry during front crawl swimming style; ii) swimmers that perform unilateral breathing present greater asymmetry in comparison to others that use bilateral breathing; iii) swimmers of best performance present smaller asymmetry than their counterparts; iv) repeated front crawl swimming movements influence body asymmetry. 18 swimmers were assessed for propulsive force parameters (peak force, mean force, impulse and rate of force development) during a maximal front crawl tethered-swimming test lasting 2 min. A factorial analysis showed that propulsive forces decreased at the beginning, intermediate and end of the test (pforce parameters (p>0.05). When performance was considered (below or above mean group time), a larger asymmetry was found in the sub-group of lower performance in comparison to those of best performance (pforces can be detected using tethered-swimming. The propulsive forces decreased during the test but asymmetries did not change under testing conditions. Although breathing preference did not influence asymmetry, swimmers with best performance were less asymmetric than their counterparts. © Georg Thieme Verlag KG Stuttgart · New York.

  17. How Do Wings Generate Lift?

    Indian Academy of Sciences (India)

    Newton's second law of motion. Hence if a wing can generate lift equal to its weight (total weight of the vehicle) it can balance the gravitational pull and can maintain level flight. The equations for fluid flow that are equivalent to the second law are the well- known Navier–Stokes (N–S) equations [1]. These equations have.

  18. Werner helicase wings DNA binding

    OpenAIRE

    Hoadley, Kelly A.; Keck, James L.

    2010-01-01

    In this issue of Structure, Kitano et al. describe the structure of the DNA-bound winged-helix domain from the Werner helicase. This structure of a RecQ/DNA complex offers insights into the DNA unwinding mechanisms of RecQ family helicases.

  19. On Wings: Aerodynamics of Eagles.

    Science.gov (United States)

    Millson, David

    2000-01-01

    The Aerodynamics Wing Curriculum is a high school program that combines basic physics, aerodynamics, pre-engineering, 3D visualization, computer-assisted drafting, computer-assisted manufacturing, production, reengineering, and success in a 15-hour, 3-week classroom module. (JOW)

  20. Relic density of neutrinos with primordial asymmetries.

    Science.gov (United States)

    Pastor, Sergio; Pinto, Teguayco; Raffelt, Georg G

    2009-06-19

    We study flavor oscillations in the early Universe, assuming primordial neutrino-antineutrino asymmetries. Including collisions and pair processes in the kinetic equations, we not only estimate the degree of flavor equilibration, but for the first time also kinetic equilibration among neutrinos and with the ambient plasma. Typically, the restrictive big-bang nucleosynthesis bound on the nu_{e}nu[over]_{e} asymmetry indeed applies to all flavors as claimed in the previous literature, but fine-tuned initial asymmetries always allow for a large surviving neutrino excess radiation that may show up in precision cosmological data.

  1. Automated quantification and analysis of mandibular asymmetry

    DEFF Research Database (Denmark)

    Darvann, T. A.; Hermann, N. V.; Larsen, P.

    2010-01-01

    We present an automated method of spatially detailed 3D asymmetry quantification in mandibles extracted from CT and apply it to a population of infants with unilateral coronal synostosis (UCS). An atlas-based method employing non-rigid registration of surfaces is used for determining deformation ...... after mirroring the mandible across the MSP. A principal components analysis of asymmetry characterizes the major types of asymmetry in the population, and successfully separates the asymmetric UCS mandibles from a number of less asymmetric mandibles from a control population....

  2. Witnessing Multipartite Entanglement by Detecting Asymmetry

    Directory of Open Access Journals (Sweden)

    Davide Girolami

    2017-03-01

    Full Text Available The characterization of quantum coherence in the context of quantum information theory and its interplay with quantum correlations is currently subject of intense study. Coherence in a Hamiltonian eigenbasis yields asymmetry, the ability of a quantum system to break a dynamical symmetry generated by the Hamiltonian. We here propose an experimental strategy to witness multipartite entanglement in many-body systems by evaluating the asymmetry with respect to an additive Hamiltonian. We test our scheme by simulating asymmetry and entanglement detection in a three-qubit Greenberger–Horne–Zeilinger (GHZ diagonal state.

  3. Review Results on Wing-Body Interference

    Directory of Open Access Journals (Sweden)

    Frolov Vladimir

    2016-01-01

    Full Text Available The paper presents an overview of results for wing-body interference, obtained by the author for varied wing-body combinations. The lift-curve slopes of the wing-body combinations are considered. In this paper a discrete vortices method (DVM and 2D potential model for cross-flow around fuselage are used. The circular and elliptical cross-sections of the fuselage and flat wings of various forms are considered. Calculations showed that the value of the lift-curve slopes of the wing-body combinations may exceed the same value for an isolated wing. This result confirms an experimental data obtained by other authors earlier. Within a framework of the used mathematical models the investigations to optimize the wing-body combination were carried. The present results of the optimization problem for the wing-body combination allowed to select the optimal geometric characteristics for configuration to maximize the values of the lift-curve slopes of the wing-body combination. It was revealed that maximums of the lift-curve slopes for the optimal mid-wing configuration with elliptical cross-section body had a sufficiently large relative width of the body (more than 30% of the span wing.

  4. Experimental investigation of transverse spin asymmetries in muon-p SIDIS processes: Sivers asymmetries

    CERN Document Server

    Adolph, C.; Alexakhin, V.Yu.; Alexandrov, Yu.; Alexeev, G.D.; Amoroso, A.; Antonov, A.A.; Austregesilo, A.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Bedfer, Y.; Bernhard, J.; Bertini, R.; Bettinelli, M.; Bicker, K.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Braun, C.; Bravar, A.; Bressan, A.; Burtin, E.; Capozza, L.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Crespo, M.L.; Dalla Torre, S.; Das, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Duic, V.; Dunnweber, W.; Dziewiecki, M.; Efremov, A.; Elia, C.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Fischer, H.; Franco, C.; von Hohenesche, N.du Fresne; Friedrich, J.M.; Frolov, V.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Goertz, S.; Grabmuller, S.; Grasso, A.; Grube, B.; Gushterski, R.; Guskov, A.; Guthorl, T.; Haas, F.; von Harrach, D.; Heinsius, F.H.; Herrmann, F.; Hess, C.; Hinterberger, F.; Horikawa, N.; Hoppner, Ch.; d'Hose, N.; Ishimoto, S.; Ivanov, O.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Joosten, R.; Kabuss, E.; Kang, D.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Korzenev, A.; Kotzinian, A.M.; Kouznetsov, O.; Kramer, M.; Kroumchtein, Z.V.; Kunne, F.; Kurek, K.; Lauser, L.; Lednev, A.A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Liska, T.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G.K.; Mann, A.; Marchand, C.; Martin, A.; Marzec, J.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu.V.; Moinester, M.A.; Morreale, A.; Mutter, A.; Nagaytsev, A.; Nagel, T.; Negrini, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.I.; Nowak, W.D.; Nunes, A.S.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Perevalova, E.; Pesaro, G.; Peshekhonov, D.V.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Rajotte, J.F.; Ramos, S.; Rapatsky, V.; Reicherz, G.; Richter, A.; Rocco, E.; Rondio, E.; Rossiyskaya, N.S.; Ryabchikov, D.I.; Samoylenko, V.D.; Sandacz, A.; Sapozhnikov, M.G.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schluter, T.; Schmidt, K.; Schmitt, L.; Schonning, K.; Schopferer, S.; Schott, M.; Schroder, W.; Shevchenko, O.Yu.; Silva, L.; Sinha, L.; Sissakian, A.N.; Slunecka, M.; Smirnov, G.I.; Sosio, S.; Sozzi, F.; Srnka, A.; Steiger, L.; Stolarski, M.; Sulc, M.; Sulej, R.; Suzuki, H.; Sznajder, P.; Takekawa, S.; Wolbeek, J.Ter; Tessaro, S.; Tessarotto, F.; Tkatchev, L.G.; Uhl, S.; Uman, I.; Vandenbroucke, M.; Virius, M.; Vlassov, N.V.; Wang, L.; Wilfert, M.; Windmolders, R.; Wislicki, W.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zhuravlev, N.; Zvyagin, A.

    2012-10-31

    The COMPASS Collaboration at CERN has measured the transverse spin azimuthal asymmetry of charged hadrons produced in semi-inclusive deep inelastic scattering using a 160 GeV positive muon beam and a transversely polarised NH_3 target. The Sivers asymmetry of the proton has been extracted in the Bjorken x range 0.003 0.03. The asymmetry is different from zero and positive also in the low x region, where sea-quarks dominate. The kinematic dependence of the asymmetry has also been investigated and results are given for various intervals of hadron and virtual photon fractional energy. In contrast to the case of the Collins asymmetry, the results on the Sivers asymmetry suggest a strong dependence on the four-momentum transfer to the nucleon, in agreement with the most recent calculations.

  5. Experimental examination of vorticity stripping from a wing-tip vortex in free-stream turbulence

    Science.gov (United States)

    Ghimire, Hari C.; Bailey, Sean C. C.

    2018-03-01

    Time-resolved stereoscopic particle image velocimetry measurements were conducted of a wing-tip vortex decaying in free-stream turbulence. The objective of the research was to experimentally investigate the mechanism causing the increased rate of decay of the vortex in the presence of turbulence. It was observed that the circulation of the vortex core experienced periods of rapid loss and recovery when immersed in free-stream turbulence. These events were not observed when the vortex was in a laminar free stream. A connection was made between these events and distortion of the vortex, coinciding with stripping of core fluid from the vortex core. Specifically, vortex stripping events were connected to asymmetry in the vortex core, and this asymmetry was associated with instances of rapid circulation loss. The increased rate of decay of the vortex in turbulence coincided with the formation of secondary vortical structures which wrapped azimuthally around the primary vortex.

  6. Leptogenesis and gravity: Baryon asymmetry without decays

    Directory of Open Access Journals (Sweden)

    J.I. McDonald

    2017-03-01

    Full Text Available A popular class of theories attributes the matter-antimatter asymmetry of the Universe to CP-violating decays of super-heavy BSM particles in the Early Universe. Recently, we discovered a new source of leptogenesis in these models, namely that the same Yukawa phases which provide the CP violation for decays, combined with curved-spacetime loop effects, lead to an entirely new gravitational mechanism for generating an asymmetry, driven by the expansion of the Universe and independent of the departure of the heavy particles from equilibrium. In this Letter, we build on previous work by analysing the full Boltzmann equation, exploring the full parameter space of the theory and studying the time-evolution of the asymmetry. Remarkably, we find regions of parameter space where decays play no part at all, and where the baryon asymmetry of the Universe is determined solely by gravitational effects.

  7. Leptogenesis and gravity: Baryon asymmetry without decays

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, J.I., E-mail: pymcdonald@swansea.ac.uk; Shore, G.M., E-mail: g.m.shore@swansea.ac.uk

    2017-03-10

    A popular class of theories attributes the matter-antimatter asymmetry of the Universe to CP-violating decays of super-heavy BSM particles in the Early Universe. Recently, we discovered a new source of leptogenesis in these models, namely that the same Yukawa phases which provide the CP violation for decays, combined with curved-spacetime loop effects, lead to an entirely new gravitational mechanism for generating an asymmetry, driven by the expansion of the Universe and independent of the departure of the heavy particles from equilibrium. In this Letter, we build on previous work by analysing the full Boltzmann equation, exploring the full parameter space of the theory and studying the time-evolution of the asymmetry. Remarkably, we find regions of parameter space where decays play no part at all, and where the baryon asymmetry of the Universe is determined solely by gravitational effects.

  8. Strain fluctuations and elastic constants

    Energy Technology Data Exchange (ETDEWEB)

    Parrinello, M.; Rahman, A.

    1982-03-01

    It is shown that the elastic strain fluctuations are a direct measure of elastic compliances in a general anisotropic medium; depending on the ensemble in which the fluctuation is measured either the isothermal or the adiabatic compliances are obtained. These fluctuations can now be calculated in a constant enthalpy and pressure, and hence, constant entropy, ensemble due to recent develpments in the molecular dynamics techniques. A calculation for a Ni single crystal under uniform uniaxial 100 tensile or compressive load is presented as an illustration of the relationships derived between various strain fluctuations and the elastic modulii. The Born stability criteria and the behavior of strain fluctuations are shown to be related.

  9. Gambling with Superconducting Fluctuations

    Science.gov (United States)

    Foltyn, Marek; Zgirski, Maciej

    2015-08-01

    Josephson junctions and superconducting nanowires, when biased close to superconducting critical current, can switch to a nonzero voltage state by thermal or quantum fluctuations. The process is understood as an escape of a Brownian particle from a metastable state. Since this effect is fully stochastic, we propose to use it for generating random numbers. We present protocol for obtaining random numbers and test the experimentally harvested data for their fidelity. Our work is prerequisite for using the Josephson junction as a tool for stochastic (probabilistic) determination of physical parameters such as magnetic flux, temperature, and current.

  10. Bilateral Asymmetry in the Human Pelvis.

    Science.gov (United States)

    Kurki, Helen K

    2017-04-01

    Asymmetry of the human axial skeleton has received much less attention that of the limb skeleton. Pelvic morphology is subject to multiple selective factors, including bipedal locomotion and obstetrics, among others, as well as environmental factors such as biomechanical loading. How these various factors influence or restrict asymmetry of the pelvis is unknown and few studies have investigated levels and patterns of pelvic asymmetry. This study examines percentage directional (%DA) and absolute (%AA) asymmetry in 14 bilaterally paired dimensions of the pelvic canal, non-canal pelvis, and femur in female (n = 111) and male (n = 126) skeletons from nine geographically dispersed skeletal samples. Directional asymmetries were uniformly low for all measures and lacked any consistent patterning across the variables, while %AA was highest in the pelvic canal, particularly the posterior aspects. Few sex differences and no population differences were found for %DA and %AA; however the latter was correlated with coefficients of variation across the 14 variables in both sexes. While sample mean %DA were low, standard deviations of the canal variables were high and the majority of individuals in both sexes displayed %DA values >±0.5, suggesting asymmetry is common, if not directionally consistent. Biomechanical loading of the pelvic girdle may influence asymmetry of both the canal and non-canal aspects of the pelvis; however it is unlikely that these asymmetries negatively affect obstetric function, given the prevalence for %DA found in this study. Anat Rec, 300:653-665, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  11. Bottom production asymmetries at the LHC

    International Nuclear Information System (INIS)

    Norrbin, E.; Vogt, R.

    1999-01-01

    We present results on bottom hadron production asymmetries at the LHC within both the Lund string fragmentation model and the intrinsic bottom model. The main aspects of the models are summarized and specific predictions for pp collisions at 14 TeV are given. Asymmetries are found to be very small at central rapidities increasing to a few percent at forward rapidities. At very large rapidities intrinsic production could dominate but this region is probably out of reach of any experiment

  12. Bottom production asymmetries at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Norrbin, E.; Vogt, R.

    1999-01-01

    We present results on bottom hadron production asymmetries at the LHC within both the Lund string fragmentation model and the intrinsic bottom model. The main aspects of the models are summarized and specific predictions for pp collisions at 14 TeV are given. Asymmetries are found to be very small at central rapidities increasing to a few percent at forward rapidities. At very large rapidities intrinsic production could dominate but this region is probably out of reach of any experiment.

  13. On the asymmetry of selected Fraunhofer lines

    International Nuclear Information System (INIS)

    Kostik, R.I.; Orlova, T.V.

    1977-01-01

    An analysis is made of the asymmetry of Fraunhofer lines observed with the double-pass monochromator of the horizontal solar telescope ASU-5 of the Main Astronomical Observatory of the Ukrainian Academy of Sciences. The conclusion is that the character of macromotion in the radial direction varies with height; in a tangential direction the motions at different depths are homogeneous. The asymmetry of weak lines is due to convection rather than to wave motions. (Auth.)

  14. Expanding signaling-molecule wavefront model of cell polarization in the Drosophila wing primordium.

    Science.gov (United States)

    Wortman, Juliana C; Nahmad, Marcos; Zhang, Peng Cheng; Lander, Arthur D; Yu, Clare C

    2017-07-01

    In developing tissues, cell polarization and proliferation are regulated by morphogens and signaling pathways. Cells throughout the Drosophila wing primordium typically show subcellular localization of the unconventional myosin Dachs on the distal side of cells (nearest the center of the disc). Dachs localization depends on the spatial distribution of bonds between the protocadherins Fat (Ft) and Dachsous (Ds), which form heterodimers between adjacent cells; and the Golgi kinase Four-jointed (Fj), which affects the binding affinities of Ft and Ds. The Fj concentration forms a linear gradient while the Ds concentration is roughly uniform throughout most of the wing pouch with a steep transition region that propagates from the center to the edge of the pouch during the third larval instar. Although the Fj gradient is an important cue for polarization, it is unclear how the polarization is affected by cell division and the expanding Ds transition region, both of which can alter the distribution of Ft-Ds heterodimers around the cell periphery. We have developed a computational model to address these questions. In our model, the binding affinity of Ft and Ds depends on phosphorylation by Fj. We assume that the asymmetry of the Ft-Ds bond distribution around the cell periphery defines the polarization, with greater asymmetry promoting cell proliferation. Our model predicts that this asymmetry is greatest in the radially-expanding transition region that leaves polarized cells in its wake. These cells naturally retain their bond distribution asymmetry after division by rapidly replenishing Ft-Ds bonds at new cell-cell interfaces. Thus we predict that the distal localization of Dachs in cells throughout the pouch requires the movement of the Ds transition region and the simple presence, rather than any specific spatial pattern, of Fj.

  15. ``Green's function'' approach & low-mode asymmetries

    Science.gov (United States)

    Masse, Laurent; Clark, Dan; Salmonson, Jay; MacLaren, Steve; Ma, Tammy; Khan, Shahab; Pino, Jesse; Ralph, Jo; Czajka, C.; Tipton, Robert; Landen, Otto; Kyrala, Georges; 2 Team; 1 Team

    2017-10-01

    Long wavelength, low mode asymmetries are believed to play a leading role in limiting the performance of current ICF implosions on NIF. These long wavelength modes are initiated and driven by asymmetries in the x-ray flux from the hohlraum; however, the underlying hydrodynamics of the implosion also act to amplify these asymmetries. The work presented here aim to deepen our understanding of the interplay of the drive asymmetries and the underlying implosion hydrodynamics in determining the final imploded configuration. This is accomplished through a synthesis of numerical modeling, analytic theory, and experimental data. In detail, we use a Green's function approach to connect the drive asymmetry seen by the capsule to the measured inflight and hot spot symmetries. The approach has been validated against a suite of numerical simulations. Ultimately, we hope this work will identify additional measurements to further constrain the asymmetries and increase hohlraum illumination design flexibility on the NIF. The technique and derivation of associated error bars will be presented. LLC, (LLNS) Contract No. DE-AC52-07NA27344.

  16. A Drosophila wing spot test

    International Nuclear Information System (INIS)

    Ayaki, Toshikazu; Yoshikawa, Isao; Niikawa, Norio; Hoshi, Masaharu.

    1986-01-01

    A Drosophila wing spot test system was used to investigate the effects of low doses of X-rays, gamma rays, and both 2.3 and 14.1 MeV neutrons on somatic chromosome mutation (SCM) induction. The incidence of SCM was significantly increased with any type of radiation, with evident linear dose-response relationship within the range of 3 to 20 cGy. It was estimated that relative biological effectiveness value for SCM induction of 2.3 MeV neutrons to X-rays and gamma rays is much higher than that of 14.1 MeV neutrons to those photons (2.4 vs 8.0). The Drosophila wing spot test system seems to become a promising in vivo experimental method for higher animals in terms of the lack of necessity for a marvelously large number of materials required in conventional test system. (Namekawa, K.)

  17. Effects of wing locations on wing rock induced by forebody vortices

    Directory of Open Access Journals (Sweden)

    Ma Baofeng

    2016-10-01

    Full Text Available Previous studies have shown that asymmetric vortex wakes over slender bodies exhibit a multi-vortex structure with an alternate arrangement along a body axis at high angle of attack. In this investigation, the effects of wing locations along a body axis on wing rock induced by forebody vortices was studied experimentally at a subcritical Reynolds number based on a body diameter. An artificial perturbation was added onto the nose tip to fix the orientations of forebody vortices. Particle image velocimetry was used to identify flow patterns of forebody vortices in static situations, and time histories of wing rock were obtained using a free-to-roll rig. The results show that the wing locations can affect significantly the motion patterns of wing rock owing to the variation of multi-vortex patterns of forebody vortices. As the wing locations make the forebody vortices a two-vortex pattern, the wing body exhibits regularly divergence and fixed-point motion with azimuthal variations of the tip perturbation. If a three-vortex pattern exists over the wing, however, the wing-rock patterns depend on the impact of the highest vortex and newborn vortex. As the three vortices together influence the wing flow, wing-rock patterns exhibit regularly fixed-points and limit-cycled oscillations. With the wing moving backwards, the newborn vortex becomes stronger, and wing-rock patterns become fixed-points, chaotic oscillations, and limit-cycled oscillations. With further backward movement of wings, the vortices are far away from the upper surface of wings, and the motions exhibit divergence, limit-cycled oscillations and fixed-points. For the rearmost location of the wing, the wing body exhibits stochastic oscillations and fixed-points.

  18. Artificial insect wings of diverse morphology for flapping-wing micro air vehicles

    International Nuclear Information System (INIS)

    Shang, J K; Finio, B M; Wood, R J; Combes, S A

    2009-01-01

    The development of flapping-wing micro air vehicles (MAVs) demands a systematic exploration of the available design space to identify ways in which the unsteady mechanisms governing flapping-wing flight can best be utilized for producing optimal thrust or maneuverability. Mimicking the wing kinematics of biological flight requires examining the potential effects of wing morphology on flight performance, as wings may be specially adapted for flapping flight. For example, insect wings passively deform during flight, leading to instantaneous and potentially unpredictable changes in aerodynamic behavior. Previous studies have postulated various explanations for insect wing complexity, but there lacks a systematic approach for experimentally examining the functional significance of components of wing morphology, and for determining whether or not natural design principles can or should be used for MAVs. In this work, a novel fabrication process to create centimeter-scale wings of great complexity is introduced; via this process, a wing can be fabricated with a large range of desired mechanical and geometric characteristics. We demonstrate the versatility of the process through the creation of planar, insect-like wings with biomimetic venation patterns that approximate the mechanical properties of their natural counterparts under static loads. This process will provide a platform for studies investigating the effects of wing morphology on flight dynamics, which may lead to the design of highly maneuverable and efficient MAVs and insight into the functional morphology of natural wings.

  19. The costae presenting in high-temperature-induced vestigial wings ...

    Indian Academy of Sciences (India)

    Most of the wings have defects in the wing blade and partially formed wing margin, which are the result of autonomous cell death in the ... [Yang D. 2007 The costae presenting in high-temperature-induced vestigial wings of Drosophila: implications for anterior wing margin formation. J. Genet. .... The relevant gene(s) may be.

  20. Fluctuations in Supercooled Fluids and Ionic Solutions

    Science.gov (United States)

    Thorpe, Dayton Gray

    An overview of five studies is presented in two parts. The first part presents two studies of supercooled fluids. The second part presents three studies of water and aqueous solutions. Each study seeks a minimal model of a condensed matter system. In the first study, kinetically constrained models (KCM's) are compared to alternative theories of the glass transition in high dimensions. Dimensionality is used as a parameter to tune the connectivity of a lattice, where a higher dimensional model has more interactions between neighboring sites. This study finds that KCM's outperform alternative theories in high dimensions. The second study explores the possibility that bacteria have evolved to exploit the glass transition to enter a dormant state when environmental conditions are unfavorable. Although the available evidence shows that the bacterial cytoplasm does not meet the strict definition of a fragile glass former, much of its behavior is similar to and can be described using close analogies with the glass transition. In the second part, the third study describes the molecular mechanisms that gives rise to large electric field fluctuations, which in turn cause autoionization and ion dissociation. The fourth study analyzes several candidate order parameters as the basis for a Gaussian field theory of ion solvation. Finally, the fifth study discusses the most popular current explanation for observed charge asymmetry at liquid-vapor interfaces. This explanation, based on linear response of the surface polarization to the presence of an ion, is incorrect. Instead, the surface polarization responds non-linearly to the presence of an ion. Incorporating these non-linear fluctuations is essential to predict solvation free energies.

  1. Role of wing morphing in thrust generation

    Directory of Open Access Journals (Sweden)

    Mehdi Ghommem

    2014-01-01

    Full Text Available In this paper, we investigate the role of morphing on flight dynamics of two birds by simulating the flow over rigid and morphing wings that have the characteristics of two different birds, namely the Giant Petrel and Dove Prion. The simulation of a flapping rigid wing shows that the root of the wing should be placed at a specific angle of attack in order to generate enough lift to balance the weight of the bird. However, in this case the generated thrust is either very small, or even negative, depending on the wing shape. Further, results show that morphing of the wing enables a significant increase in the thrust and propulsive efficiency. This indicates that the birds actually utilize some sort of active wing twisting and bending to produce enough thrust. This study should facilitate better guidance for the design of flapping air vehicles.

  2. Fluctuations in email size

    Science.gov (United States)

    Matsubara, Yoshitsugu; Musashi, Yasuo

    2017-12-01

    The purpose of this study is to explain fluctuations in email size. We have previously investigated the long-term correlations between email send requests and data flow in the system log of the primary staff email server at a university campus, finding that email size frequency follows a power-law distribution with two inflection points, and that the power-law property weakens the correlation of the data flow. However, the mechanism underlying this fluctuation is not completely understood. We collected new log data from both staff and students over six academic years and analyzed the frequency distribution thereof, focusing on the type of content contained in the emails. Furthermore, we obtained permission to collect "Content-Type" log data from the email headers. We therefore collected the staff log data from May 1, 2015 to July 31, 2015, creating two subdistributions. In this paper, we propose a model to explain these subdistributions, which follow log-normal-like distributions. In the log-normal-like model, email senders -consciously or unconsciously- regulate the size of new email sentences according to a normal distribution. The fitting of the model is acceptable for these subdistributions, and the model demonstrates power-law properties for large email sizes. An analysis of the length of new email sentences would be required for further discussion of our model; however, to protect user privacy at the participating organization, we left this analysis for future work. This study provides new knowledge on the properties of email sizes, and our model is expected to contribute to the decision on whether to establish upper size limits in the design of email services.

  3. Quantitative dermatoglyphic asymmetry: a comparative study between schizophrenic patients and control groups of West Bengal, India.

    Science.gov (United States)

    Karmakar, B; Sengupta, M

    2012-01-01

    Quantitative Fluctuating (FA) and Directional asymmetry (DA) of dermatoglyphics on digito-palmar complex were analyzed in a group of 111 patients (males: 61, females: 50) with schizophrenia (SZ), and compared to an ethnically matched phenotypically healthy control (males: 60, females: 60) through MANOVA, ANOVA and canonical Discriminant analyses. With few exceptions, asymmetries are higher among patients, and this is more prominent in FA than DA. Statistically significant differences were observed between patient and control groups, especially in males. In both sexes, FA of combined dermatoglyphic traits (e.g. total finger ridge count, total palmar pattern ridge count) are found to be a strong discriminator between the two groups with a correct classification of over 83% probability.

  4. Big Bang or vacuum fluctuation

    International Nuclear Information System (INIS)

    Zel'dovich, Ya.B.

    1980-01-01

    Some general properties of vacuum fluctuations in quantum field theory are described. The connection between the ''energy dominance'' of the energy density of vacuum fluctuations in curved space-time and the presence of singularity is discussed. It is pointed out that a de-Sitter space-time (with the energy density of the vacuum fluctuations in the Einstein equations) that matches the expanding Friedman solution may describe the history of the Universe before the Big Bang. (P.L.)

  5. Analysis of bat wings for morphing

    Science.gov (United States)

    Leylek, Emily A.; Manzo, Justin E.; Garcia, Ephrahim

    2008-03-01

    The morphing of wings from three different bat species is studied using an extension of the Weissinger method. To understand how camber affects performance factors such as lift and lift to drag ratio, XFOIL is used to study thin (3% thickness to chord ratio) airfoils at a low Reynolds number of 100,000. The maximum camber of 9% yielded the largest lift coefficient, and a mid-range camber of 7% yielded the largest lift to drag ratio. Correlations between bat wing morphology and flight characteristics are covered, and the three bat wing planforms chosen represent various combinations of morphological components and different flight modes. The wings are studied using the extended Weissinger method in an "unmorphed" configuration using a thin, symmetric airfoil across the span of the wing through angles of attack of 0°-15°. The wings are then run in the Weissinger method at angles of attack of -2° to 12° in a "morphed" configuration modeled after bat wings seen in flight, where the camber of the airfoils comprising the wings is varied along the span and a twist distribution along the span is introduced. The morphed wing configurations increase the lift coefficient over 1000% from the unmorphed configuration and increase the lift to drag ratio over 175%. The results of the three different species correlate well with their flight in nature.

  6. Veins improve fracture toughness of insect wings.

    Directory of Open Access Journals (Sweden)

    Jan-Henning Dirks

    Full Text Available During the lifetime of a flying insect, its wings are subjected to mechanical forces and deformations for millions of cycles. Defects in the micrometre thin membranes or veins may reduce the insect's flight performance. How do insects prevent crack related material failure in their wings and what role does the characteristic vein pattern play? Fracture toughness is a parameter, which characterises a material's resistance to crack propagation. Our results show that, compared to other body parts, the hind wing membrane of the migratory locust S. gregaria itself is not exceptionally tough (1.04±0.25 MPa√m. However, the cross veins increase the wing's toughness by 50% by acting as barriers to crack propagation. Using fracture mechanics, we show that the morphological spacing of most wing veins matches the critical crack length of the material (1132 µm. This finding directly demonstrates how the biomechanical properties and the morphology of locust wings are functionally correlated in locusts, providing a mechanically 'optimal' solution with high toughness and low weight. The vein pattern found in insect wings thus might inspire the design of more durable and lightweight artificial 'venous' wings for micro-air-vehicles. Using the vein spacing as indicator, our approach might also provide a basis to estimate the wing properties of endangered or extinct insect species.

  7. Thermal and quantal isospin and spin fluctuations in heavy ion reactions

    International Nuclear Information System (INIS)

    Moretto, L.G.

    1980-01-01

    The isobaric charge distributions are discussed in terms of quantal and classical isospin fluctuations. The roles of mass asymmetry and of the higher giant isovector modes are treated within the framework of a cylinder model that is worked out exactly. Spin fluctuations are considered first in terms of quantal fluctuations in a cylinder model and second in terms of thermal fluctuations in a two-sphere model. The results are applied to the calculation of in- and out-of-plane angular distributions for sequential fission, alpha and gamma decay. Analytical expressions are obtained for the angular distributions. The theoretical predictions are compared with experimental results for sequential fission, alpha, and gamma angular distributions. 23 figures

  8. Quad-thopter: Tailless Flapping Wing Robot with 4 Pairs of Wings

    NARCIS (Netherlands)

    de Wagter, C.; Karasek, M.; de Croon, G.C.H.E.; J.-M. Moschetta G. Hattenberger, H. de Plinval

    2017-01-01

    We present a novel design of a tailless flapping wing Micro Air Vehicle (MAV), which uses four independently driven pairs of flapping wings in order to fly and perform agile maneuvers. The wing pairs are arranged such that differential thrust generates the desired roll and pitch moments, similar to

  9. A female melanin ornament signals offspring fluctuating asymmetry in the barn owl

    NARCIS (Netherlands)

    Roulin, A; Ducrest, AL; Balloux, F; Dijkstra, Cornelis; Riols, C

    2003-01-01

    Sexual selection theory predicts that males advertise quality by displaying extravagant ornaments. By contrast, whether phenotypic variation in females has a signalling function remains an open question. Here, to our knowledge, we provide the first evidence that a female plumage trait can signal

  10. Magnetic fluctuations associated with density fluctuations in the tokamak edge

    International Nuclear Information System (INIS)

    Kim, Y.J.; Gentle, K.W.; Ritz, C.P.; Rhodes, T.L.; Bengtson, R.D.

    1989-01-01

    Electrostatic density and potential fluctuations occurring with high amplitude near the edge of a tokamak are correlated with components of the fluctuating magnetic field measured outside the limiter radius. It has been established that this turbulence is associated with fluctuations in current as well as density and potential. The correlation extends for substantial toroidal distances, but only if the probes are displaced approximately along field lines, consistent with the short coherence lengths poloidally but long coherence lengths parallel to the field which are characteristic for this turbulence. Furthermore, the correlation can be found only with density fluctuations measured inside the limiter radius; density fluctuations behind the limiter have no detectable magnetic concomitant for the toroidally spaced probes used here. (author). Letter-to-the-editor. 12 refs, 3 figs

  11. Fluctuations of pT from initial size fluctuations

    International Nuclear Information System (INIS)

    Chojnacki, M.; Broniowski, W.; Obara, L.

    2010-01-01

    We investigate the initial transverse size of the source, which comes directly from the Glauber treatment of the earliest stage of relativistic heavy-ion collisions. After the hydrodynamic evolution stage the fluctuations in the transverse velocity flow at the hadronic freeze-out are transformed into the even-by-event fluctuations of the average transverse momentum. The Glauber phase is simulated by GLISSANDO and followed by a realistic hydrodynamic evolution stage. The statistical hadronization is performed by the THERMINATOR. We describe the pT fluctuations at RHIC, in particular the magnitude of the effect, its centrality dependence, and the weak dependence on the incident energy. The results show that the observed event-by-event p T fluctuations are mainly caused by the initial source size fluctuations. (author)

  12. Superheavy thermal dark matter and primordial asymmetries

    International Nuclear Information System (INIS)

    Bramante, Joseph; Unwin, James

    2017-01-01

    The early universe could feature multiple reheating events, leading to jumps in the visible sector entropy density that dilute both particle asymmetries and the number density of frozen-out states. In fact, late time entropy jumps are usually required in models of Affleck-Dine baryogenesis, which typically produces an initial particle-antiparticle asymmetry that is much too large. An important consequence of late time dilution, is that a smaller dark matter annihilation cross section is needed to obtain the observed dark matter relic density. For cosmologies with high scale baryogenesis, followed by radiation-dominated dark matter freeze-out, we show that the perturbative unitarity mass bound on thermal relic dark matter is relaxed to 10 10 GeV. We proceed to study superheavy asymmetric dark matter models, made possible by a sizable entropy injection after dark matter freeze-out, and identify how the Affleck-Dine mechanism would generate the baryon and dark asymmetries.

  13. Transverse spin dependent azimuthal asymmetries at COMPASS

    CERN Document Server

    Parsamyan, Bakur

    2011-01-01

    In semi-inclusive deep inelastic scattering of polarized leptons on a transversely polarized target eight target transverse spin-dependent azimuthal modulations are allowed. In the QCD parton model half of these asymmetries can be interpreted within the leading order approach and the other four are twist-three contributions. The first two leading twist asymmetries extracted by HERMES and COMPASS experiments are related: one to the transversity distribution and the Collins effect, the other to the Sivers distribution function. These results triggered a lot of interest in the past few years and allowed the first extractions of the transversity and the Sivers distribution functions of nucleon. The remaining six asymmetries were obtained by the COMPASS experiment using a 160 GeV/c longitudinally polarized muon beam and transversely polarized deuteron and proton targets. Here we review preliminary results from COMPASS proton data of 2007.

  14. Adaptive wing : Investigations of passive wing technologies for loads reduction in the cleansky smart fixed wing aircraft (SFWA) project

    NARCIS (Netherlands)

    Kruger, W.R.; Dillinger, J; De Breuker, R.; Reyes, M.; Haydn, K.

    2016-01-01

    In the work package “Adaptive Wing” in the Clean-Sky “Smart Fixed Wing Aircraft” (SFWA) project, design processes and solutions for aircraft wings have been created, giving optimal response with respect to loads, comfort and performance by the introduction of passive and active concepts. Central

  15. Biomolecules: Fluctuations and relaxations

    Science.gov (United States)

    Parak, F.; Ostermann, A.; Gassmann, A.; Scherk, C.; Chong, S.-H.; Kidera, A.; Go, N.

    1999-10-01

    The normal-mode refinement of X-ray crystallographic data opened a new possibility to analyze the mean-square displacements in a protein molecule. A comparison of the X-ray structure of myoglobin at several temperatures with Mössbauer data is performed. In the low-temperature regime below 180 K the iron mean-square displacements obtained by Mössbauer spectroscopy are in good agreement with a normal-mode analysis. The X-ray mean-square displacements at the position of the iron, after the motion originated from the external degrees of freedom are subtracted, have practically the same temperature dependence as those from Mössbauer spectroscopy. The difference between the X-ray mean-square displacements and those predicted by normal-mode analysis measures the distribution of molecules into conformational substates. Above 180 K the Mössbauer effect indicates fluctuations between conformational substates. The relaxation from a Fe(III) conformation to a Fe(II) conformation is shown for superoxide dismutase of Propionibacterium shermanii.

  16. Asymmetries in Chickens from Lines Selected and Relaxed for High or Low Antibody Titers to Sheep Red Blood Cells

    Directory of Open Access Journals (Sweden)

    Yunjie Tu

    2015-03-01

    Full Text Available Wattle length, width, and area were measured to classify bilateral asymmetries in four lines of chickens. The lines were the S26 generation of White Leghorns selected for high (HAS or low (LAS response to sheep red blood cells and sublines in which selection had been relaxed for three generations (high antibody relaxed [HAR] and low antibody relaxed [LAR]. Antibody titers (AB were greater for HAS than for HAR with both greater than for LAS and LAR which while different for males did not differ for females. The low antibody lines were heavier and reached sexual maturity at younger age than the high antibody lines. In general, wattle length, width, and area were greater in the low than high antibody lines. In 24 comparisons for bilaterality 18 exhibited fluctuating asymmetry and 6 exhibited directional asymmetry with 5 of the 6 being for wattle length. There was not a clear pattern for changes in degree of asymmetry when selection was relaxed for 3 generations. For females, the relative asymmetry (RA of wattle area was larger (p≤0.05 for HAR than for LAR and not different from the selected lines and relaxed lines. There were no differences among lines for RA of wattle length and width of females and wattle length, width, and area of males.

  17. Quark Model Contributions to Parton Flavor Asymmetry

    Science.gov (United States)

    Benesh, C. J.; Olivares, V.; Londergan, J. T.

    2003-04-01

    Simple Quark model calculations of the nucleon sea yield an excess of baru over bard anti-quarks, exactly opposite to what is observed. By calculating the effects of flavor-dependent corrections to the energies of the lowest lying four 4Q-barQ states in the sea, we investigate the extent to which the sign of the flavor asymmetry can be reversed in these models without the explicit introduction of mesonic degrees of freedom. Sea quark polarizations and charge asymmetries are also calculated.

  18. The gluon Sivers asymmetry measurements at COMPASS

    CERN Document Server

    Szabelski, Adam

    2017-01-01

    The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons. As such, a nonzero Sivers effect for gluons could be a signature of their nonzero orbital angular momentum inside the nucleon. COMPASS has collected data of semi-inclusive deep inelastic scattering by impinging 160 GeV/$c$ muons on transversely polarised proton and deuteron targets. The gluon Sivers asymmetry is extracted from a high-$p_T$ hadron pair sample with the use of monte carlo simulations and the a neural network approach. The results of a similar analysis for a Collins-like asymmetry for gluons will also be given.

  19. Particle-antiparticle asymmetries from annihilations.

    Science.gov (United States)

    Baldes, Iason; Bell, Nicole F; Petraki, Kalliopi; Volkas, Raymond R

    2014-10-31

    An extensively studied mechanism to create particle-antiparticle asymmetries is the out-of-equilibrium and CP violating decay of a heavy particle. We, instead, examine how asymmetries can arise purely from 2→2 annihilations rather than from the usual 1→2 decays and inverse decays. We review the general conditions on the reaction rates that arise from S-matrix unitarity and CPT invariance, and show how these are implemented in the context of a simple toy model. We formulate the Boltzmann equations for this model, and present an example solution.

  20. Top (and Bottom) asymmetries at the LHC

    CERN Document Server

    Pinamonti, Michele; The ATLAS collaboration

    2015-01-01

    The latest top pair production charge asymmetry measurements by the ATLAS and CMS Collaborations are presented: inclusive and differential measurements in the single lepton and dilepton channels based on the full 7 TeV data-set, a combination of the 7 TeV single lepton measurements by the two experiments, and a measurement in the single lepton channel on the full 8 TeV data-set performed by the CMS experiment. The first measurement of the bottom pair producion charge asymmetry by the LHCb experiment is also mentioned.

  1. Nonequilibrium fluctuations in a resistor.

    Science.gov (United States)

    Garnier, N; Ciliberto, S

    2005-06-01

    In small systems where relevant energies are comparable to thermal agitation, fluctuations are of the order of average values. In systems in thermodynamical equilibrium, the variance of these fluctuations can be related to the dissipation constant in the system, exploiting the fluctuation-dissipation theorem. In nonequilibrium steady systems, fluctuations theorems (FT) additionally describe symmetry properties of the probability density functions (PDFs) of the fluctuations of injected and dissipated energies. We experimentally probe a model system: an electrical dipole driven out of equilibrium by a small constant current I, and show that FT are experimentally accessible and valid. Furthermore, we stress that FT can be used to measure the dissipated power P = R I2 in the system by just studying the PDFs' symmetries.

  2. Suppressing Quantum Fluctuations in Classicalization

    CERN Document Server

    Vikman, Alexander

    2013-01-01

    We study vacuum quantum fluctuations of simple Nambu-Goldstone bosons - derivatively coupled single scalar-field theories possessing shift-symmetry in field space. We argue that quantum fluctuations of the interacting field can be drastically suppressed with respect to the free-field case. Moreover, the power-spectrum of these fluctuations can soften to become red for sufficiently small scales. In quasiclassical approximation, we demonstrate that this suppression can only occur for those theories that admit such classical static backgrounds around which small perturbations propagate faster than light. Thus a quasiclassical softening of quantum fluctuations is only possible for theories which classicalize instead of having a usual Lorentz invariant and local Wilsonian UV- completion. We illustrate our analysis by estimating the quantum fluctuations for the DBI-like theories.

  3. Gravitons and light cone fluctuations

    International Nuclear Information System (INIS)

    Ford, L.H.

    1995-01-01

    Gravitons in a squeezed vacuum state, the natural result of quantum creation in the early Universe or by black holes, will introduce metric fluctuations. These metric fluctuations will introduce fluctuations of the light cone. It is shown that when the various two-point functions of a quantized field are averaged over the metric fluctuations, the light cone singularity disappears for distinct points. The metric-averaged functions remain singular in the limit of coincident points. The metric-averaged retarded Green's function for a massless field becomes a Gaussian which is nonzero both inside and outside of the classical light cone. This implies some photons propagate faster than the classical light speed, whereas others propagate slower. The possible effects of metric fluctuations upon one-loop quantum processes are discussed and illustrated by the calculation of the one-loop electron self-energy

  4. The Realization and Study of Optical Wings

    Science.gov (United States)

    Artusio-Glimpse, Alexandra Brae

    Consider the airfoil: a carefully designed structure capable of stable lift in a uniform air flow. It so happens that air pressure and radiation (light) pressure are similar phenomena because each transfer momentum to flow-disturbing objects. This, then, begs the question: does an optical analogue to the airfoil exist? Though an exceedingly small effect, scientists harness radiation pressure in a wide gamut of applications from micromanipulation of single biological particles to the propulsion of large spacecrafts called solar sails. We introduce a cambered, refractive rod that is subjected to optical forces analogous to those seen in aerodynamics, and I call this analogue the optical wing. Flight characteristics of optical wings are determined by wing shape and material in a uniform radiation field. Theory predicts the lift force and axial torque are functions of the wing's angle of attack with stable and unstable orientations. These structures can operate as intensity-dependent, parametrically driven oscillators. In two-dimensions, the wings exhibit bistability when analyzed in an accelerating frame. In three-dimensions, the motion of axially symmetric spinning hemispherical wings is analogous to a spinning top. Experiments on semi-buoyant wings in water found semicylindrically shaped, refractive microparticles traversed a laser beam and rotated to an illumination-dependent stable orientation. Preliminary tests aid in the development of a calibrated force measurement experiment to directly evaluate the optical forces and torque on these samples. A foundational study of the optical wing, this work contributes to future advancements of flight-by-light.

  5. The Crest Wing Wave Energy Device

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Antonishen, Michael Patrick

    This report presents the results of a continuation of an experimental study of the wave energy converting abilities of the Crest Wing wave energy converter (WEC), in the following referred to as ‘Phase 2'. The Crest Wing is a WEC that uses its movement in matching the shape of an oncoming wave...

  6. Veins Improve Fracture Toughness of Insect Wings

    Science.gov (United States)

    Dirks, Jan-Henning; Taylor, David

    2012-01-01

    During the lifetime of a flying insect, its wings are subjected to mechanical forces and deformations for millions of cycles. Defects in the micrometre thin membranes or veins may reduce the insect’s flight performance. How do insects prevent crack related material failure in their wings and what role does the characteristic vein pattern play? Fracture toughness is a parameter, which characterises a material’s resistance to crack propagation. Our results show that, compared to other body parts, the hind wing membrane of the migratory locust S. gregaria itself is not exceptionally tough (1.04±0.25 MPa√m). However, the cross veins increase the wing’s toughness by 50% by acting as barriers to crack propagation. Using fracture mechanics, we show that the morphological spacing of most wing veins matches the critical crack length of the material (1132 µm). This finding directly demonstrates how the biomechanical properties and the morphology of locust wings are functionally correlated in locusts, providing a mechanically ‘optimal’ solution with high toughness and low weight. The vein pattern found in insect wings thus might inspire the design of more durable and lightweight artificial ‘venous’ wings for micro-air-vehicles. Using the vein spacing as indicator, our approach might also provide a basis to estimate the wing properties of endangered or extinct insect species. PMID:22927966

  7. Effect of leading edge roundness on a delta wing in wing-rock motion

    Science.gov (United States)

    Ng, T. Terry; Malcolm, Gerald N.

    1990-01-01

    The effect of wing leading-edge roundness on wing rock was investigated using flow visualization in a water tunnel. Eighty degree delta wing models were tested on free-to-roll and forced oscillation rigs. The onset of wing rock was delayed by increasing the roundness of the leading edges. The wing rock amplitude and frequency results suggested that damping was increased at lower angles of attack but reduced at higher angles of attack. Vortex lift-off and vortex breakdown, especially during dynamic situations, were strongly affected by the leading edge roundness. Different forms of wing rock motion could be sustained by combinations of vortex breakdown and vortex lift-off. Behaviors of the wing and vortex motions were explained by the influence of leading edge roundness on the separation location, vortex trajectory, and vortex breakdown.

  8. Quantum fluctuations from thermal fluctuations in Jacobson formalism

    Energy Technology Data Exchange (ETDEWEB)

    Faizal, Mir [University of British Columbia-Okanagan, Irving K. Barber School of Arts and Sciences, Kelowna, BC (Canada); University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada); Ashour, Amani; Alcheikh, Mohammad [Damascus University, Mathematics Department, Faculty of Science, Damascus (Syrian Arab Republic); Alasfar, Lina [Universite Clermont Auvergne, Laboratoire de Physique Corpusculaire de Clermont-Ferrand, Aubiere (France); Alsaleh, Salwa; Mahroussah, Ahmed [King Saud University, Department of Physics and Astronomy, Riyadh (Saudi Arabia)

    2017-09-15

    In the Jacobson formalism general relativity is obtained from thermodynamics. This is done by using the Bekenstein-Hawking entropy-area relation. However, as a black hole gets smaller, its temperature will increase. This will cause the thermal fluctuations to also increase, and these will in turn correct the Bekenstein-Hawking entropy-area relation. Furthermore, with the reduction in the size of the black hole, quantum effects will also start to dominate. Just as the general relativity can be obtained from thermodynamics in the Jacobson formalism, we propose that the quantum fluctuations to the geometry can be obtained from thermal fluctuations. (orig.)

  9. Frontal Brain Asymmetry and Willingness to Pay

    DEFF Research Database (Denmark)

    Ramsøy, Thomas Z.; Skov, Martin; Christensen, Maiken K.

    2018-01-01

    measure-the prefrontal gamma asymmetry-was most strongly related to WTP responses, and was most coupled to the actual decision phase. These findings are discussed in light of the psychology of WTP calculations, and in relation to the recent emergence of consumer neuroscience and neuromarketing....

  10. Frontal Brain Asymmetry and Willingness to Pay.

    Science.gov (United States)

    Ramsøy, Thomas Z; Skov, Martin; Christensen, Maiken K; Stahlhut, Carsten

    2018-01-01

    Consumers frequently make decisions about how much they are willing to pay (WTP) for specific products and services, but little is known about the neural mechanisms underlying such calculations. In this study, we were interested in testing whether specific brain activation-the asymmetry in engagement of the prefrontal cortex-would be related to consumer choice. Subjects saw products and subsequently decided how much they were willing to pay for each product, while undergoing neuroimaging using electroencephalography. Our results demonstrate that prefrontal asymmetry in the gamma frequency band, and a trend in the beta frequency band that was recorded during product viewing was significantly related to subsequent WTP responses. Frontal asymmetry in the alpha band was not related to WTP decisions. Besides suggesting separate neuropsychological mechanisms of consumer choice, we find that one specific measure-the prefrontal gamma asymmetry-was most strongly related to WTP responses, and was most coupled to the actual decision phase. These findings are discussed in light of the psychology of WTP calculations, and in relation to the recent emergence of consumer neuroscience and neuromarketing.

  11. Neutron contribution to nuclear DVCS asymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Vadim Guzey

    2008-01-22

    Using a simple model for nuclear GPDs, we study the role of the neutron contribution to nuclear DVCS observables. As an example, we use the beam-spin asymmetry $A_{LU}^A$ measured in coherent and incoherent DVCS on a wide range of nuclear targets in the HERMES and JLab kinematics. We find that at small values of the momentum transfer $t$, $A_{LU}^A$ is dominated by the coherent-enriched contribution, which enhances $A_{LU}^A$ compared to the free proton asymmetry $A_{LU}^p$, $A_{LU}^A(\\phi)/A_{LU}^p(\\phi)=1.8-2.2$. At large values of $t$, the nuclear asymmetry is dominated by the incoherent contribution and $A_{LU}^A/(\\phi)A_{LU}^p(\\phi)=0.66-0.74$. The deviation of $A_{LU}^A(\\phi)/A_{LU}^p(\\phi)$ from unity at large $t$ is a result of the neutron contribution, which gives a possibility to constain neutron GPDs in incoherent nuclear DVCS. A similar trend is expected for other DVCS asymmetries.

  12. Lower limb asymmetry in mechanical muscle function

    DEFF Research Database (Denmark)

    Jordan, M J; Aagaard, Per; Herzog, W

    2015-01-01

    ) for kinetic impulse (CMJ and SJ phase-specific kinetic impulse AI). Dual x-ray absorptiometry scanning was used to assess asymmetry in lower body muscle mass. Compared with controls, ACL-R skiers had increased AI in muscle mass (P 

  13. Effect of stress on structural brain asymmetry

    Czech Academy of Sciences Publication Activity Database

    Zach, P.; Valeš, Karel; Stuchlík, Aleš; Čermáková, P.; Mrzílková, J.; Koutella, A.; Kutová, M.

    2016-01-01

    Roč. 37, č. 4 (2016), s. 253-264 ISSN 0172-780X R&D Projects: GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:67985823 Keywords : laterality * asymmetry * brain * evolution * stress * neuropsychiatric disorders Subject RIV: FH - Neurology Impact factor: 0.918, year: 2016

  14. Spin asymmetries in inclusive cross sections

    International Nuclear Information System (INIS)

    Shima, T.

    1981-01-01

    Using the now closed Argonne ZGS polarized-proton beam, and the Michigan polarized-proton target, we have studied the one-spin and two-spin asymmetries of pion and proton production in the inclusive reactions p up arrow + p up arrow → p + Anything, and p up arrow + p up arrow → pi/sup +/ + Anything at P/sub lab/ = 6, 11.75, and 12.75 GeV/c. We observed experimental one-spin and two-spin asymmetries by scattering the polarized-proton beam from our polarized-proton target in each of the four possible initial spin states. These inclusive one-spin and two-spin asymmetries were calculated using the measured experimental spin asymmetries and three types of background measurements taken at P/sub lab/ = 6 and 11.75 GeV/c. We varied the transverse momentum P/sub perpendicular/) of the outgoing pion or proton from 0.71 to 1.55 GeV/c, and Feynman x variable from -0.08 to 0.67

  15. Binomial distribution for the charge asymmetry parameter

    International Nuclear Information System (INIS)

    Chou, T.T.; Yang, C.N.

    1984-01-01

    It is suggested that for high energy collisions the distribution with respect to the charge asymmetry z = nsub(F) - nsub(B) is binomial, where nsub(F) and nsub(B) are the forward and backward charge multiplicities. (orig.)

  16. Dominant limb asymmetry associated with prospective injury ...

    African Journals Online (AJOL)

    The purpose of the study was to identify associations between dominant lower limb asymmetry in unanticipated agility performance and prospective injury occurrence. Female netball players (N=24) performed unanticipated 180° turn agility sprints on both the dominant and non-dominant legs interspersed with an additional ...

  17. Infant Frontal Asymmetry Predicts Child Emotional Availability

    Science.gov (United States)

    Licata, Maria; Paulus, Markus; Kühn-Popp, Nina; Meinhardt, Jorg; Sodian, Beate

    2015-01-01

    While factors influencing maternal emotional availability (EA) have been well investigated, little is known about the development of child EA. The present longitudinal study investigated the role of frontal brain asymmetry in young children with regard to child EA (child responsiveness and involvement) in mother-child interaction in a sample of 28…

  18. Exploring handedness asymmetries in the Simon effect.

    Science.gov (United States)

    Seibold, Julia C; Chen, Jing; Proctor, Robert W

    2016-02-01

    Spatially corresponding stimulus-response pairings usually produce shorter reaction times (RTs) than do non-corresponding pairings, even when the spatial dimension of the stimulus is irrelevant to the task. This "Simon effect" for visual stimuli and manual responses is often larger for the stimulus location on the side to which the person's dominant hand is operating. The present study aimed at replicating and examining the nature of this asymmetry. To determine whether the Simon effect asymmetry is a function of the hand distinction or of conceptual spatial codes, performance with left and right manual key-presses was compared to that with vocal responses "left" and "right." Whether the asymmetric Simon effect pattern is restricted to spatial stimuli was tested by comparing effects obtained with left and right located squares to those found with the centered words Left and Right. The asymmetry was only replicated for the spatial stimulus-manual response Simon task, for which a second experiment showed similar results when the hands and response box were not visible during task performance. The analysis revealed a general dominant-hand RT advantage that similarly adds to both corresponding and non-corresponding trials and is rather independent from the Simon effect. This advantage yields an apparent asymmetry when the data are analyzed as a function of correspondence for each stimulus location because the corresponding and non-corresponding RTs that are compared come from different hands.

  19. Measuring Asymmetry in Insect-Plant Networks

    Energy Technology Data Exchange (ETDEWEB)

    Cruz, Claudia P T [Programa de Pos-Graduacao em Fisica, Universidade Federal do Rio Grande do Norte, UFRN - Campus Universitario, Lagoa Nova, CEP 59078 972, Natal, RN (Brazil); De Almeida, Adriana M [Departamento de Botanica, Ecologia e Zoologia, Centro de Biociencias, Universidade Federal do Rio Grande do Norte, UFRN - Campus Universitario, Lagoa Nova, CEP 59078 972, Natal, RN (Brazil); Corso, Gilberto, E-mail: claudia@dfte.ufrn.br, E-mail: adrianam@ufrn.br, E-mail: corso@cb.ufrn.br [Departamento de Biofisica e Farmacologia, Centro de Biociencias, Universidade Federal do Rio Grande do Norte, UFRN - Campus Universitario, Lagoa Nova, CEP 59078 972, Natal, RN (Brazil)

    2011-03-01

    In this work we focus on interaction networks between insects and plants and in the characterization of insect plant asymmetry, an important issue in coevolution and evolutionary biology. We analyze in particular the asymmetry in the interaction matrix of animals (herbivorous insects) and plants (food resource for the insects). Instead of driving our attention to the interaction matrix itself we derive two networks associated to the bipartite network: the animal network, D{sub 1}, and the plant network, D{sub 2}. These networks are constructed according to the following recipe: two animal species are linked once if they interact with the same plant. In a similar way, in the plant network, two plants are linked if they interact with the same animal. To explore the asymmetry between D{sub 2} and D{sub 1} we test for a set of 23 networks from the ecologic literature networks: the difference in size, {Delta}L, clustering coefficient difference, {Delta}C, and mean connectivity difference, {Delta}. We used a nonparametric statistical test to check the differences in {Delta}L, {Delta}C and {Delta}. Our results indicate that {Delta}L and {Delta} show a significative asymmetry.

  20. Spectral fluctuations and zeta functions

    International Nuclear Information System (INIS)

    Balazs, N.L.; Schmit, C.; Voros, A.

    1987-01-01

    The study theoretically and numerically the role of the fluctuations of eigenvalue spectra {μ/sub n} in a particular analytical continuation process applied to the (generalized) zeta function Z(s) = Σ/sub n/μ/sub n//sup -s/ for s large and positive. A particularly interesting example is the spectrum of the Laplacian on a triangular domain which tessellates a compact surface of constant negative curvature (of genus two). The authors indeed find that the fluctuations restrict the abscissa of convergence, and also affect the rate of convergence. This then initiates a new approach to the exploration of spectral fluctuations through the convergence of analytical continuation processes

  1. Fluctuation theorem: A critical review

    Science.gov (United States)

    Malek Mansour, M.; Baras, F.

    2017-10-01

    Fluctuation theorem for entropy production is revisited in the framework of stochastic processes. The applicability of the fluctuation theorem to physico-chemical systems and the resulting stochastic thermodynamics were analyzed. Some unexpected limitations are highlighted in the context of jump Markov processes. We have shown that these limitations handicap the ability of the resulting stochastic thermodynamics to correctly describe the state of non-equilibrium systems in terms of the thermodynamic properties of individual processes therein. Finally, we considered the case of diffusion processes and proved that the fluctuation theorem for entropy production becomes irrelevant at the stationary state in the case of one variable systems.

  2. Hovering hummingbird wing aerodynamics during the annual cycle. II. Implications of wing feather moult

    Science.gov (United States)

    Sapir, Nir; Elimelech, Yossef

    2018-01-01

    Birds usually moult their feathers in a particular sequence which may incur aerodynamic, physiological and behavioural implications. Among birds, hummingbirds are unique species in their sustained hovering flight. Because hummingbirds frequently hover-feed, they must maintain sufficiently high flight capacities even when moulting their flight feathers. A hummingbird wing consists of 10 primary flight feathers whose absence during moult may strongly affect wing performance. Using dynamic similarity rules, we compared time-accurate aerodynamic loads and flow field measurements over several wing geometries that follow the natural feather moult sequence of Calypte anna, a common hummingbird species in western North America. Our results suggest a drop of more than 20% in lift production during the early stages of the moult sequence in which mid-wing flight feathers are moulted. We also found that the wing's ability to generate lift strongly depended on the morphological integrity of the outer primaries and leading-edge. These findings may explain the evolution of wing morphology and moult attributes. Specifically, the high overlap between adjacent wing feathers, especially at the wing tip, and the slow sequential replacement of the wing feathers result in a relatively small reduction in wing surface area during moult with limited aerodynamic implications. We present power and efficiency analyses for hover flight during moult under several plausible scenarios, suggesting that body mass reduction could be a compensatory mechanism that preserves the energetic costs of hover flight. PMID:29515884

  3. Semi-automated quantitative Drosophila wings measurements.

    Science.gov (United States)

    Loh, Sheng Yang Michael; Ogawa, Yoshitaka; Kawana, Sara; Tamura, Koichiro; Lee, Hwee Kuan

    2017-06-28

    Drosophila melanogaster is an important organism used in many fields of biological research such as genetics and developmental biology. Drosophila wings have been widely used to study the genetics of development, morphometrics and evolution. Therefore there is much interest in quantifying wing structures of Drosophila. Advancement in technology has increased the ease in which images of Drosophila can be acquired. However such studies have been limited by the slow and tedious process of acquiring phenotypic data. We have developed a system that automatically detects and measures key points and vein segments on a Drosophila wing. Key points are detected by performing image transformations and template matching on Drosophila wing images while vein segments are detected using an Active Contour algorithm. The accuracy of our key point detection was compared against key point annotations of users. We also performed key point detection using different training data sets of Drosophila wing images. We compared our software with an existing automated image analysis system for Drosophila wings and showed that our system performs better than the state of the art. Vein segments were manually measured and compared against the measurements obtained from our system. Our system was able to detect specific key points and vein segments from Drosophila wing images with high accuracy.

  4. The Fluctuation Niche in Plants

    International Nuclear Information System (INIS)

    Terradas, J.; Penuelas, J.; Lloret, F.; Penuelas, J.

    2009-01-01

    Classical approaches to niche in coexisting plants have undervalued temporal fluctuations. We propose that fluctuation niche is an important dimension of the total niche and interacts with habitat and life-history niches to provide a better understanding of the multidimensional niche space where ecological interactions occur. To scale a fluctuation niche, it is necessary to relate environmental constrictions or species performance not only to the absolute values of the usual environmental and eco physiological variables but also to their variances or other measures of variability. We use Mediterranean plant communities as examples, because they present characteristic large seasonal and inter annual fluctuations in water and nutrient availabilities, along an episodic-constant gradient, and because the plant responses include a number of syndromes coupled to this gradient.

  5. The Fluctuation Niche in Plants

    Directory of Open Access Journals (Sweden)

    Jaume Terradas

    2009-01-01

    Full Text Available Classical approaches to niche in coexisting plants have undervalued temporal fluctuations. We propose that fluctuation niche is an important dimension of the total niche and interacts with habitat and life-history niches to provide a better understanding of the multidimensional niche space where ecological interactions occur. To scale a fluctuation niche, it is necessary to relate environmental constrictions or species performance not only to the absolute values of the usual environmental and ecophysiological variables but also to their variances or other measures of variability. We use Mediterranean plant communities as examples, because they present characteristic large seasonal and interannual fluctuations in water and nutrient availabilities, along an episodic-constant gradient, and because the plant responses include a number of syndromes coupled to this gradient.

  6. Molecular evolution under fitness fluctuations.

    Science.gov (United States)

    Mustonen, Ville; Lässig, Michael

    2008-03-14

    Molecular evolution is a stochastic process governed by fitness, mutations, and reproductive fluctuations in a population. Here, we study evolution where fitness itself is stochastic, with random switches in the direction of selection at individual genomic loci. As the correlation time of these fluctuations becomes larger than the diffusion time of mutations within the population, fitness changes from an annealed to a quenched random variable. We show that the rate of evolution has its maximum in the crossover regime, where both time scales are comparable. Adaptive evolution emerges in the quenched fitness regime (evidence for such fitness fluctuations has recently been found in genomic data). The joint statistical theory of reproductive and fitness fluctuations establishes a conceptual connection between evolutionary genetics and statistical physics of disordered systems.

  7. Fluctuating attention in Parkinson's disease

    DEFF Research Database (Denmark)

    Starrfelt, Randi; Aarsland, Dag; Janvin, Carmen

    2001-01-01

    great variability in performance in reactiontime tasks. Aiming to investigate fluctuation of attention in PD, we re- analysed data from a cue-target reactiontime task, specifically searching for differences in variability between patients and controls. The subjects included were a representative group...... a significant difference (pattention might be fluctuating on a moment to moment basis in PD. Some of the PD patients have also been tested with a choice reaction time...... task, shown by Walker et al. (2000) to be sensi- tive to fluctuation of cognition in DLB patients. Preliminary data-analysis indicate that PD patients also show considerable intra-individual variation in performance on this test. These findings suggest that fluctuating attention and cogni- tion...

  8. Fluctuations and Instability in Sedimentation

    KAUST Repository

    Guazzelli, Élisabeth

    2011-01-21

    This review concentrates on the fluctuations of the velocities of sedimenting spheres, and on the structural instability of a suspension of settling fibers. For many years, theoretical estimates and numerical simulations predicted the fluctuations of the velocities of spheres to increase with the size of the container, whereas experiments found no such variation. Two ideas have increased our understanding. First, the correlation length of the velocity fluctuations was found experimentally to be 20 interparticle separations. Second, in dilute suspensions, a vertical variation in the concentration due to the spreading of the front with the clear fluid can inhibit the velocity fluctuations. In a very dilute regime, a homogeneous suspension of fibers suffers a spontaneous instability in which fast descending fiber-rich columns are separated by rising fiber-sparse columns. In a semidilute regime, the settling is hindered, more so than for spheres. © 2011 by Annual Reviews. All rights reserved.

  9. Nonequilibrium quantum fluctuations of work.

    Science.gov (United States)

    Allahverdyan, A E

    2014-09-01

    The concept of work is basic for statistical thermodynamics. To gain a fuller understanding of work and its (quantum) features, it needs to be represented as an average of a fluctuating quantity. Here I focus on the work done between two moments of time for a thermally isolated quantum system driven by a time-dependent Hamiltonian. I formulate two natural conditions needed for the fluctuating work to be physically meaningful for a system that starts its evolution from a nonequilibrium state. The existing definitions do not satisfy these conditions due to issues that are traced back to noncommutativity. I propose a definition of fluctuating work that is free of previous drawbacks and that applies for a wide class of nonequilibrium initial states. It allows the deduction of a generalized work-fluctuation theorem that applies for an arbitrary (out-of-equilibrium) initial state.

  10. Novel Control Effectors for Truss Braced Wing

    Science.gov (United States)

    White, Edward V.; Kapania, Rakesh K.; Joshi, Shiv

    2015-01-01

    At cruise flight conditions very high aspect ratio/low sweep truss braced wings (TBW) may be subject to design requirements that distinguish them from more highly swept cantilevered wings. High aspect ratio, short chord length and relative thinness of the airfoil sections all contribute to relatively low wing torsional stiffness. This may lead to aeroelastic issues such as aileron reversal and low flutter margins. In order to counteract these issues, high aspect ratio/low sweep wings may need to carry additional high speed control effectors to operate when outboard ailerons are in reversal and/or must carry additional structural weight to enhance torsional stiffness. The novel control effector evaluated in this study is a variable sweep raked wing tip with an aileron control surface. Forward sweep of the tip allows the aileron to align closely with the torsional axis of the wing and operate in a conventional fashion. Aft sweep of the tip creates a large moment arm from the aileron to the wing torsional axis greatly enhancing aileron reversal. The novelty comes from using this enhanced and controllable aileron reversal effect to provide roll control authority by acting as a servo tab and providing roll control through intentional twist of the wing. In this case the reduced torsional stiffness of the wing becomes an advantage to be exploited. The study results show that the novel control effector concept does provide roll control as described, but only for a restricted class of TBW aircraft configurations. For the configuration studied (long range, dual aisle, Mach 0.85 cruise) the novel control effector provides significant benefits including up to 12% reduction in fuel burn.

  11. Primordial fluctuations from nonlinear couplings

    International Nuclear Information System (INIS)

    Calzetta, E.A.; Gonorazky, S.

    1997-01-01

    We study the spectrum of primordial fluctuations in theories where the inflaton field is nonlinearly coupled to massless fields and/or to itself. Conformally invariant theories generically predict a scale-invariant spectrum. Scales entering the theory through infrared divergences cause logarithmic corrections to the spectrum, tilting it towards the blue. We discuss in some detail whether these fluctuations are quantum or classical in nature. copyright 1997 The American Physical Society

  12. Electron scattering wings on lines in interacting supernovae

    Science.gov (United States)

    Huang, Chenliang; Chevalier, Roger A.

    2018-03-01

    We consider the effect of electron scattering on lines emitted as a result of supernova interaction with a circumstellar medium, assuming that the scattering occurs in ionized gas in the pre-shock circumstellar medium. The single scattering case gives the broad component in the limit of low optical depth, showing a velocity full width half-maximum that is close to the thermal velocities of electrons. The line shape is approximately exponential at low velocities and steepens at higher velocities. At higher optical depths, the line profile remains exponential at low velocities, but wings strengthen with increasing optical depth. In addition to the line width, the ratio of narrow to broad (scattered) line strength is a possible diagnostic of the gas. The results depend on the density profile of the circumstellar gas, especially if the scattering and photon creation occur in different regions. We apply the scattering model to a number of supernovae, including Type IIn and Type Ia-circumstellar medium (CSM) events. The asymmetry to the red found in some cases can be explained by scattering in a fast wind region that is indicated by observations.

  13. The inverse problems of wing panel manufacture processes

    Science.gov (United States)

    Oleinikov, A. I.; Bormotin, K. S.

    2013-12-01

    It is shown that inverse problems of steady-state creep bending of plates in both the geometrically linear and nonlinear formulations can be represented in a variational formulation. Steady-state values of the obtained functionals corresponding to the solutions of the problems of inelastic deformation and springback are determined by applying a finite element procedure to the functionals. Optimal laws of creep deformation are formulated using the criterion of minimizing damage in the functionals of the inverse problems. The formulated problems are reduced to the problems solved by the finite element method using MSC.Marc software. Currently, forming of light metals poses tremendous challenges due to their low ductility at room temperature and their unusual deformation characteristics at hot-cold work: strong asymmetry between tensile and compressive behavior, and a very pronounced anisotropy. We used the constitutive models of steady-state creep of initially transverse isotropy structural materials the kind of the stress state has influence. The paper gives basics of the developed computer-aided system of design, modeling, and electronic simulation targeting the processes of manufacture of wing integral panels. The modeling results can be used to calculate the die tooling, determine the panel processibility, and control panel rejection in the course of forming.

  14. Asymmetric statistical features of the Chinese domestic and international gold price fluctuation

    Science.gov (United States)

    Cao, Guangxi; Zhao, Yingchao; Han, Yan

    2015-05-01

    Analyzing the statistical features of fluctuation is remarkably significant for financial risk identification and measurement. In this study, the asymmetric detrended fluctuation analysis (A-DFA) method was applied to evaluate asymmetric multifractal scaling behaviors in the Shanghai and New York gold markets. Our findings showed that the multifractal features of the Chinese and international gold spot markets were asymmetric. The gold return series persisted longer in an increasing trend than in a decreasing trend. Moreover, the asymmetric degree of multifractals in the Chinese and international gold markets decreased with the increase in fluctuation range. In addition, the empirical analysis using sliding window technology indicated that multifractal asymmetry in the Chinese and international gold markets was characterized by its time-varying feature. However, the Shanghai and international gold markets basically shared a similar asymmetric degree evolution pattern. The American subprime mortgage crisis (2008) and the European debt crisis (2010) enhanced the asymmetric degree of the multifractal features of the Chinese and international gold markets. Furthermore, we also make statistical tests for the results of multifractatity and asymmetry, and discuss the origin of them. Finally, results of the empirical analysis using the threshold autoregressive conditional heteroskedasticity (TARCH) and exponential generalized autoregressive conditional heteroskedasticity (EGARCH) models exhibited that good news had a more significant effect on the cyclical fluctuation of the gold market than bad news. Moreover, good news exerted a more significant effect on the Chinese gold market than on the international gold market.

  15. Nonlinear Structures Optimization for Flexible Flapping Wing MAVs

    Science.gov (United States)

    2009-02-01

    nonlinear optimization, flapping wing, fluid structure interaction, micro -air vehicles, flexible wing, flapping mechanism 16. SECURITY... Structures Optimization for Flexible Flapping Wing Micro -Air Vehicles” was funded with Chief Scientist Innovative Research funds. This project was divided...predict a 10% resisting load to the model, and Python Scripting to wrap around everything. 2 Building the Model in Abaqus CAE The flapping wing

  16. Generic Wing-Body Aerodynamics Data Base

    Science.gov (United States)

    Holst, Terry L.; Olsen, Thomas H.; Kwak, Dochan (Technical Monitor)

    2001-01-01

    The wing-body aerodynamics data base consists of a series of CFD (Computational Fluid Dynamics) simulations about a generic wing body configuration consisting of a ogive-circular-cylinder fuselage and a simple symmetric wing mid-mounted on the fuselage. Solutions have been obtained for Nonlinear Potential (P), Euler (E) and Navier-Stokes (N) solvers over a range of subsonic and transonic Mach numbers and angles of attack. In addition, each solution has been computed on a series of grids, coarse, medium and fine to permit an assessment of grid refinement errors.

  17. Unemployment and Right-Wing Extremist Crime

    OpenAIRE

    Falk, Armin; Zweimüller, Josef

    2005-01-01

    Right-wing extremism is a serious problem in many societies. A prominent hypothesis states that unemployment plays a crucial role for the occurrence of right-wing extremist crime. In this paper we empirically test this hypothesis. We use a previously not used data set which includes all officially recorded right-wing criminal acts in Germany. These data are recorded by the German Federal Criminal Police Office on a monthly and state level basis. Our main finding is that there is in fact a sig...

  18. Sagittal otolith morphogenesis asymmetry in marine fishes.

    Science.gov (United States)

    Mille, T; Mahe, K; Villanueva, M C; De Pontual, H; Ernande, B

    2015-09-01

    This study investigated and compared asymmetry in sagittal otolith shape and length between left and right inner ears in four roundfish and four flatfish species of commercial interest. For each species, the effects of ontogenetic changes (individual age and total body length), sexual dimorphism (individual sex) and the otolith's location on the right or left side of the head, on the shape and length of paired otoliths (between 143 and 702 pairs according to species) were evaluated. Ontogenetic changes in otolith shape and length were observed for all species. Sexual dimorphism, either in otolith shape and length or in their ontogenetic changes, was detected for half of the species, be they round or flat. Significant directional asymmetry in otolith shape and length was detected in one roundfish species each, but its inconsistency across species and its small average amplitude (6·17% for shape and 1·99% for length) suggested that it has barely any biological relevance. Significant directional asymmetry in otolith shape and length was found for all flatfish species except otolith length for one species. Its average amplitude varied between 2·06 and 17·50% for shape and between 0·00 and 11·83% for length and increased significantly throughout ontogeny for two species, one dextral and one sinistral. The longer (length) and rounder otolith (shape) appeared to be always on the blind side whatever the species. These results suggest differential biomineralization between the blind and ocular inner ears in flatfish species that could result from perturbations of the proximal-distal gradient of otolith precursors in the endolymph and the otolith position relative to the geometry of the saccular epithelium due to body morphology asymmetry and lateralized behaviour. The fact that asymmetry never exceeded 18% even at the individual level suggests an evolutionary canalization of otolith shape symmetry to avoid negative effects on fish hearing and balance. Technically

  19. FijiWings: an open source toolkit for semiautomated morphometric analysis of insect wings.

    Science.gov (United States)

    Dobens, Alexander C; Dobens, Leonard L

    2013-08-07

    Development requires coordination between cell proliferation and cell growth to pattern the proper size of tissues, organs, and whole organisms. The Drosophila wing has landmark features, such as the location of veins patterned by cell groups and trichome structures produced by individual cells, that are useful to examine the genetic contributions to both tissue and cell size. Wing size and trichome density have been measured manually, which is tedious and error prone, and although image processing and pattern-recognition software can quantify features in micrographs, this approach has not been applied to insect wings. Here we present FijiWings, a set of macros designed to perform semiautomated morphophometric analysis of a wing photomicrograph. FijiWings uses plug-ins installed in the Fiji version of ImageJ to detect and count trichomes and measure wing area either to calculate trichome density of a defined region selected by the user or generate a heat map of overall trichome densities. For high-throughput screens we have developed a macro that directs a trainable segmentation plug-in to detect wing vein locations either to measure trichome density in specific intervein regions or produce a heat map of relative intervein areas. We use wing GAL4 drivers and UAS-regulated transgenes to confirm the ability of these tools to detect changes in overall tissue growth and individual cell size. FijiWings is freely available and will be of interest to a broad community of fly geneticists studying both the effect of gene function on wing patterning and the evolution of wing morphology.

  20. Interplay among transversity induced asymmetries in hadron leptoproduction

    CERN Document Server

    Adolph, C.; Alexeev, M.G.; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Augustyniak, W.; Austregesilo, A.; Azevedo, C.D.R.; Badelek, B.; Balestra, F.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Buchele, M.; Burtin, E.; Chang, W.C.; Chiosso, M.; Choi, I.; Chung, S.U.; Cicuttin, A.; Crespo, M.L.; Curiel, Q.; d'Hose, N.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Duic, V.; Dziewiecki, M.; Efremov, A.; Elia, C.; Eversheim, P.D.; Eyrich, W.; Ferrero, A.; Finger, M.; M. Finger jr; Fischer, H.; Franco, C.; von Hohenesche, N. du Fresne; Friedrich, J.M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grabmuller, S.; Grasso, A.; Grosse-Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; Hahne, D.; von Harrach, D.; Hashimoto, R.; Heinsius, F.H.; Herrmann, F.; Hinterberger, F.; Horikawa, N.; Hsieh, C.Yu; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jorg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.; Kramer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z.V.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Lednev, A.A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Marchand, C.; Marianski, B.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Montuenga, P.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nikolaenko, V.I.; Novy, J.; Nowak, W.D.; Nukazuka, G.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.C.; Pereira, F.; Pesaro, G.; Pesek, M.; Peshekhonov, D.V.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rossiyskaya, N.S.; Ryabchikov, D.I.; Rychter, A.; Samoylenko, V.D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schonning, K.; Schopferer, S.; Selyunin, A.; Shevchenko, O.Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sozzi, F.; Srnka, A.; Stolarski, M.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Wolbeek, J. ter; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tosello, F.; Tskhay, V.; Uhl, S.; Veloso, J.; Virius, M.; Weisrock, T.; Wilfert, M.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.

    2016-01-01

    In the fragmentation of a transversely polarized quark several left-right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A phenomenological analysis of the data allows to establish quantitative relationships among them, providing strong indication that the underlying fragmentation mechanisms are all driven ...

  1. The leading-edge vortex of swift-wing shaped delta wings

    Science.gov (United States)

    Muir, Rowan; Arredondo-Galeana, Abel; Viola, Ignazio Maria

    2017-11-01

    Recent investigations on the aerodynamics of natural fliers have illuminated the significance of the Leading-Edge Vortex (LEV) for lift generation in a variety of flight conditions. In this investigation, a model non-slender delta shaped wing with a sharp leading-edge is tested at low Reynolds Number, along with a delta wing of the same design, but with a modified trailing edge inspired by the wing of a common swift Apus apus. The effect of the tapering swift wing on LEV development and stability is compared with the flow structure over the un-modified delta wing model through particle image velocimetry. For the first time, a leading-edge vortex system consisting of a dual or triple LEV is recorded on a swift-wing shaped delta wing, where such a system is found across all tested conditions. It is shown that the spanwise location of LEV breakdown is governed by the local chord rather than Reynolds Number or angle of attack. These findings suggest that the trailing-edge geometry of the swift wing alone does not prevent the common swift from generating an LEV system comparable with that of a delta shaped wing. This work received funding from the Engineering and Physical Sciences Research Council [EP/M506515/1] and the Consejo Nacional de Ciencia y Tecnología (CONACYT).

  2. Fruit fly scale robots can hover longer with flapping wings than with spinning wings.

    Science.gov (United States)

    Hawkes, Elliot W; Lentink, David

    2016-10-01

    Hovering flies generate exceptionally high lift, because their wings generate a stable leading edge vortex. Micro flying robots with a similar wing design can generate similar high lift by either flapping or spinning their wings. While it requires less power to spin a wing, the overall efficiency depends also on the actuator system driving the wing. Here, we present the first holistic analysis to calculate how long a fly-inspired micro robot can hover with flapping versus spinning wings across scales. We integrate aerodynamic data with data-driven scaling laws for actuator, electronics and mechanism performance from fruit fly to hummingbird scales. Our analysis finds that spinning wings driven by rotary actuators are superior for robots with wingspans similar to hummingbirds, yet flapping wings driven by oscillatory actuators are superior at fruit fly scale. This crossover is driven by the reduction in performance of rotary compared with oscillatory actuators at smaller scale. Our calculations emphasize that a systems-level analysis is essential for trading-off flapping versus spinning wings for micro flying robots. © 2016 The Author(s).

  3. GDH Integral on the Proton from Asymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Prok, Yelena [Univ. of Virginia, Charlottesville, VA (United States)

    2004-05-01

    Inclusive double spin electron asymmetries have been measured by scattering polarized electrons off the solid polarized 15NH3 target in Hall B of Jefferson Lab in 2000-2001. The virtual photon asymmetry A1 (x), the longitudinal spin structure function, g1 (x, Q2), and the first moment, γ1p, have been evaluated for a kinematic range of 0.05 ≥ Q2 ≥ 4.5 GeV2. The extracted results complement the existing data in the resonance region, extending it to lower and higher Q2 regions. The results are important in the study of Q2 evolution of nucleon structure from the hadronic to partonic degrees of freedom.

  4. Quantum Correlations Evolution Asymmetry in Quantum Channels

    International Nuclear Information System (INIS)

    Li Meng; Huang Yun-Feng; Guo Guang-Can

    2017-01-01

    It was demonstrated that the entanglement evolution of a specially designed quantum state in the bistochastic channel is asymmetric. In this work, we generalize the study of the quantum correlations, including entanglement and quantum discord, evolution asymmetry to various quantum channels. We found that the asymmetry of entanglement and quantum discord only occurs in some special quantum channels, and the behavior of the entanglement evolution may be quite different from the behavior of the quantum discord evolution. To quantum entanglement, in some channels it decreases monotonously with the increase of the quantum channel intensity. In some other channels, when we increase the intensity of the quantum channel, it decreases at first, then keeps zero for some time, and then rises up. To quantum discord, the evolution becomes more complex and you may find that it evolutes unsmoothly at some points. These results illustrate the strong dependence of the quantum correlations evolution on the property of the quantum channels. (paper)

  5. Flow Modulation and Force Control of Flapping Wings

    Science.gov (United States)

    2014-10-29

    tested on a flapping wing model in the oil tank. Robotic flapper equipped with DC motors drove the wing model, and the imbedded servo motor could flap...the overall wake structure on the hovering wings. Totally, two volumetric flow measurements were performed on two mechanical flappers with different...wing kinematics but similar wing geometry. On the flappers with small stroke angle and passive rotation, the general vortex wake structure

  6. Tax asymmetries and corporate income tax reform

    OpenAIRE

    Myers, Stewart C.; Majd, Saman.

    1986-01-01

    This paper investigates the impact of tax asymmetries (the lack of full loss offsets) under current corporate income tax law and a stylized tax reform proposal. The government's tax claim on the firm's pretax cash flows is modelled as a series of path-dependent call options and valued by option pricing procedures and Monte Carlo simulation.The tax reform investigated reduces the statutory tax rate, eliminates the investment tax credit and sets tax depreciation approximately equal to economic ...

  7. Relic neutrino asymmetry evolution from first principles

    International Nuclear Information System (INIS)

    Bell, N.F.; Volkas, R.R.; Wong, Y.Y.Y.

    1998-09-01

    The exact Quantum Kinetic Equations for a two-flavour active-sterile neutrino system are used to provide a systematic derivation of approximate evolution equations for the relic neutrino asymmetry. An extension of the adiabatic approximation for matter-affected neutrino oscillations is developed which incorporates decoherence due to collisions. Exact and approximate expressions for the decoherence and repopulation functions are discussed. A first pass is made over the exact treatment of multi-flavour partially incoherent oscillations. (authors)

  8. Detecting Gait Asymmetry with Wearable Accelerometers

    Science.gov (United States)

    2015-03-18

    goal is to utilize these features to detect actual injuries, with the quantification of rehabilitation progress as a logical future continuation. The...gait in post-stroke patients: Is this deficit distinct from asymmetry? a cohort study,” Journal of Neuroengineering and Rehabilitation 8(1), 23 (2011...symmetry and regularity in transfemoral amputees assessed by trunk accelerations,” J Neuroeng Rehabil 7(4) (2010). [16] D. Gouwanda and S. Arosha

  9. Measurement of semileptonic asymmetries at LHCb

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    CP violation in neutral B meson mixing is an excellent place to search for the effects of new physics beyond the Standard Model. I report on the first measurements of the CP violating semileptonic asymmetries in the B_s0 and B_d0 systems from LHCb. Both are consistent with the Standard Model expectations and are the most precise single measurements of these parameters to date.

  10. Left-Wing Extremism: The Current Threat

    Energy Technology Data Exchange (ETDEWEB)

    Karl A. Seger

    2001-04-30

    Left-wing extremism is ''alive and well'' both in the US and internationally. Although the current domestic terrorist threat within the U. S. is focused on right-wing extremists, left-wing extremists are also active and have several objectives. Leftist extremists also pose an espionage threat to U.S. interests. While the threat to the U.S. government from leftist extremists has decreased in the past decade, it has not disappeared. There are individuals and organizations within the U.S. who maintain the same ideology that resulted in the growth of left-wing terrorism in this country in the 1970s and 1980s. Some of the leaders from that era are still communicating from Cuba with their followers in the U.S., and new leaders and groups are emerging.

  11. A galactic microquasar mimicking winged radio galaxies.

    Science.gov (United States)

    Martí, Josep; Luque-Escamilla, Pedro L; Bosch-Ramon, Valentí; Paredes, Josep M

    2017-11-24

    A subclass of extragalactic radio sources known as winged radio galaxies has puzzled astronomers for many years. The wing features are detected at radio wavelengths as low-surface-brightness radio lobes that are clearly misaligned with respect to the main lobe axis. Different models compete to account for these peculiar structures. Here, we report observational evidence that the parsec-scale radio jets in the Galactic microquasar GRS 1758-258 give rise to a Z-shaped radio emission strongly reminiscent of the X and Z-shaped morphologies found in winged radio galaxies. This is the first time that such extended emission features are observed in a microquasar, providing a new analogy for its extragalactic relatives. From our observations, we can clearly favour the hydrodynamic backflow interpretation against other possible wing formation scenarios. Assuming that physical processes are similar, we can extrapolate this conclusion and suggest that this mechanism could also be at work in many extragalactic cases.

  12. Frontal Brain Asymmetry and Willingness to Pay

    Directory of Open Access Journals (Sweden)

    Thomas Z. Ramsøy

    2018-03-01

    Full Text Available Consumers frequently make decisions about how much they are willing to pay (WTP for specific products and services, but little is known about the neural mechanisms underlying such calculations. In this study, we were interested in testing whether specific brain activation—the asymmetry in engagement of the prefrontal cortex—would be related to consumer choice. Subjects saw products and subsequently decided how much they were willing to pay for each product, while undergoing neuroimaging using electroencephalography. Our results demonstrate that prefrontal asymmetry in the gamma frequency band, and a trend in the beta frequency band that was recorded during product viewing was significantly related to subsequent WTP responses. Frontal asymmetry in the alpha band was not related to WTP decisions. Besides suggesting separate neuropsychological mechanisms of consumer choice, we find that one specific measure—the prefrontal gamma asymmetry—was most strongly related to WTP responses, and was most coupled to the actual decision phase. These findings are discussed in light of the psychology of WTP calculations, and in relation to the recent emergence of consumer neuroscience and neuromarketing.

  13. Nodal signalling determines biradial asymmetry in Hydra.

    Science.gov (United States)

    Watanabe, Hiroshi; Schmidt, Heiko A; Kuhn, Anne; Höger, Stefanie K; Kocagöz, Yigit; Laumann-Lipp, Nico; Ozbek, Suat; Holstein, Thomas W

    2014-11-06

    In bilaterians, three orthogonal body axes define the animal form, with distinct anterior-posterior, dorsal-ventral and left-right asymmetries. The key signalling factors are Wnt family proteins for the anterior-posterior axis, Bmp family proteins for the dorsal-ventral axis and Nodal for the left-right axis. Cnidarians, the sister group to bilaterians, are characterized by one oral-aboral body axis, which exhibits a distinct biradiality of unknown molecular nature. Here we analysed the biradial growth pattern in the radially symmetrical cnidarian polyp Hydra, and we report evidence of Nodal in a pre-bilaterian clade. We identified a Nodal-related gene (Ndr) in Hydra magnipapillata, and this gene is essential for setting up an axial asymmetry along the main body axis. This asymmetry defines a lateral signalling centre, inducing a new body axis of a budding polyp orthogonal to the mother polyp's axis. Ndr is expressed exclusively in the lateral bud anlage and induces Pitx, which encodes an evolutionarily conserved transcription factor that functions downstream of Nodal. Reminiscent of its function in vertebrates, Nodal acts downstream of β-Catenin signalling. Our data support an evolutionary scenario in which a 'core-signalling cassette' consisting of β-Catenin, Nodal and Pitx pre-dated the cnidarian-bilaterian split. We presume that this cassette was co-opted for various modes of axial patterning: for example, for lateral branching in cnidarians and left-right patterning in bilaterians.

  14. Esthetic evaluation of dental and gingival asymmetries.

    Science.gov (United States)

    Fernandes, Liliana; Pinho, Teresa

    2015-06-01

    The aim of this study was to determine which smile asymmetries were less esthetic, dental or gingival. Laypeople (297), generalists (223), prosthodontists (50) and orthodontists (49), evaluated the esthetics of digitally-modified images taken from the same frontal intra-oral photograph, using the same lips, simulating upper maxillary midline shift, occlusal plane inclination, asymmetric incisal edge and asymmetric gingival migration. The images were later paired into 3 groups. The only ones considered esthetic were the asymmetric incisal edge of the 0.5 mm shorter upper central incisor and the asymmetric gingival migration (2 mm) of the upper central incisor. In the paired images, upper maxillary midline shift vs. occlusal plane inclination, the former was rated less esthetic, while in the asymmetric incisal edge vs. asymmetric gingival migration pair, the latter was considered to be less esthetic. Laypeople and generalists consider smiles more attractive. The only images considered esthetic were the asymmetric incisal edge of the central incisor shorter by 0.5 mm and the 2 mm asymmetric gingival migration of the upper central incisor. In the horizontal plane (maxillary midline shift vs. occlusal plane cant), the dental asymmetries were considered less esthetic than the gingival asymmetries. However, in the vertical plane (asymmetric incisal edge vs. asymmetric gingival migration) the opposite was recorded. Copyright © 2015 CEO. Published by Elsevier Masson SAS. All rights reserved.

  15. The leading-edge vortex of swift wing-shaped delta wings.

    Science.gov (United States)

    Muir, Rowan Eveline; Arredondo-Galeana, Abel; Viola, Ignazio Maria

    2017-08-01

    Recent investigations on the aerodynamics of natural fliers have illuminated the significance of the leading-edge vortex (LEV) for lift generation in a variety of flight conditions. A well-documented example of an LEV is that generated by aircraft with highly swept, delta-shaped wings. While the wing aerodynamics of a manoeuvring aircraft, a bird gliding and a bird in flapping flight vary significantly, it is believed that this existing knowledge can serve to add understanding to the complex aerodynamics of natural fliers. In this investigation, a model non-slender delta-shaped wing with a sharp leading edge is tested at low Reynolds number, along with a delta wing of the same design, but with a modified trailing edge inspired by the wing of a common swift Apus apus . The effect of the tapering swift wing on LEV development and stability is compared with the flow structure over the unmodified delta wing model through particle image velocimetry. For the first time, a leading-edge vortex system consisting of a dual or triple LEV is recorded on a swift wing-shaped delta wing, where such a system is found across all tested conditions. It is shown that the spanwise location of LEV breakdown is governed by the local chord rather than Reynolds number or angle of attack. These findings suggest that the trailing-edge geometry of the swift wing alone does not prevent the common swift from generating an LEV system comparable with that of a delta-shaped wing.

  16. Signs of Asymmetry in Exploding Stars

    Science.gov (United States)

    Hensley, Kerry

    2018-03-01

    Supernova explosions enrich the interstellar medium and can even briefly outshine their host galaxies. However, the mechanism behind these massive explosions still isnt fully understood. Could probing the asymmetry of supernova remnants help us better understand what drives these explosions?Hubble image of the remnant of supernova 1987A, one of the first remnants discovered to be asymmetrical. [ESA/Hubble, NASA]Stellar Send-OffsHigh-mass stars end their lives spectacularly. Each supernova explosion churns the interstellar medium and unleashes high-energy radiation and swarms of neutrinos. Supernovae also suffuse the surrounding interstellar medium with heavy elements that are incorporated into later generations of stars and the planets that form around them.The bubbles of expanding gas these explosions leave behind often appear roughly spherical, but mounting evidence suggests that many supernova remnants are asymmetrical. While asymmetry in supernova remnants can arise when the expanding material plows into the non-uniform interstellar medium, it can also be an intrinsic feature of the explosion itself.Simulation results clockwise from top left: Mass density, calcium mass fraction, oxygen mass fraction, nickel-56 mass fraction. Click to enlarge. [Adapted from Wollaeger et al. 2017]Coding ExplosionsThe presence or absence of asymmetry in a supernova remnant can hold clues as to what drove the explosion. But how can we best observe asymmetry in a supernova remnant? Modeling lets us explore different observational approaches.A team of scientists led by Ryan T. Wollaeger (Los Alamos National Laboratory) used radiative transfer and radiative hydrodynamics simulations to model the explosion of a core-collapse supernova. Wollaeger and collaborators introduced asymmetry into the explosion by creating a single-lobed, fast-moving outflow along one axis.Their simulations showed that while some chemical elements lingered near the origin of the explosion or were distributed

  17. Modeling fluctuations in scattered waves

    CERN Document Server

    Jakeman, E

    2006-01-01

    Fluctuations in scattered waves limit the performance of imaging and remote sensing systems that operate on all wavelengths of the electromagnetic spectrum. To better understand these fluctuations, Modeling Fluctuations in Scattered Waves provides a practical guide to the phenomenology, mathematics, and simulation of non-Gaussian noise models and discusses how they can be used to characterize the statistics of scattered waves.Through their discussion of mathematical models, the authors demonstrate the development of new sensing techniques as well as offer intelligent choices that can be made for system analysis. Using experimental results and numerical simulation, the book illustrates the properties and applications of these models. The first two chapters introduce statistical tools and the properties of Gaussian noise, including results on phase statistics. The following chapters describe Gaussian processes and the random walk model, address multiple scattering effects and propagation through an extended med...

  18. Fluctuations in the multiparticle dynamics

    International Nuclear Information System (INIS)

    Bozek, P.; Ploszajczak, M.

    1993-01-01

    The appearance and properties of intermittent fluctuations in physical systems, in particular the formation of rare structures in transport phenomena are discussed. The distribution of fluctuations approaches a limiting log-normal statistical distribution. The log-normal distribution is introduced as a simple parametrization of the energy fluctuations leading to the subthreshold production of particles in nuclear collisions, and it is shown that it fits all available data both for total π 0 production cross section as well as the π 0 kinetic energy spectra for E/A < 90 MeV. It is suggested that the same universal distribution should also describe the subthreshold production of other hadrons like η and K. (author) 36 refs., 11 figs

  19. Aeroelasticity of morphing wings using neural networks

    Science.gov (United States)

    Natarajan, Anand

    In this dissertation, neural networks are designed to effectively model static non-linear aeroelastic problems in adaptive structures and linear dynamic aeroelastic systems with time varying stiffness. The use of adaptive materials in aircraft wings allows for the change of the contour or the configuration of a wing (morphing) in flight. The use of smart materials, to accomplish these deformations, can imply that the stiffness of the wing with a morphing contour changes as the contour changes. For a rapidly oscillating body in a fluid field, continuously adapting structural parameters may render the wing to behave as a time variant system. Even the internal spars/ribs of the aircraft wing which define the wing stiffness can be made adaptive, that is, their stiffness can be made to vary with time. The immediate effect on the structural dynamics of the wing, is that, the wing motion is governed by a differential equation with time varying coefficients. The study of this concept of a time varying torsional stiffness, made possible by the use of active materials and adaptive spars, in the dynamic aeroelastic behavior of an adaptable airfoil is performed here. Another type of aeroelastic problem of an adaptive structure that is investigated here, is the shape control of an adaptive bump situated on the leading edge of an airfoil. Such a bump is useful in achieving flow separation control for lateral directional maneuverability of the aircraft. Since actuators are being used to create this bump on the wing surface, the energy required to do so needs to be minimized. The adverse pressure drag as a result of this bump needs to be controlled so that the loss in lift over the wing is made minimal. The design of such a "spoiler bump" on the surface of the airfoil is an optimization problem of maximizing pressure drag due to flow separation while minimizing the loss in lift and energy required to deform the bump. One neural network is trained using the CFD code FLUENT to

  20. Origin of cosmological density fluctuations

    International Nuclear Information System (INIS)

    Carr, B.J.

    1984-11-01

    The density fluctuations required to explain the large-scale cosmological structure may have arisen spontaneously as a result of a phase transition in the early Universe. There are several ways in which such fluctuations may have ben produced, and they could have a variety of spectra, so one should not necessarily expect all features of the large-scale structure to derive from a simple power law spectrum. Some features may even result from astrophysical amplification mechanisms rather than gravitational instability. 128 references

  1. Z0-tagged jet event asymmetry in heavy-ion collisions at the CERN large hadron collider.

    Science.gov (United States)

    Neufeld, R B; Vitev, I

    2012-06-15

    Tagged jet measurements provide a promising experimental channel to quantify the similarities and differences in the mechanisms of jet production in proton-proton and nucleus-nucleus collisions. We present the first calculation of the transverse momentum asymmetry of Z0/γ*-tagged jet events in sqrt[s]=2.76  TeV reactions at the LHC. Our results combine the O(G(F)α(s)2) perturbative cross sections with the radiative and collisional processes that modify parton showers in the presence of dense strongly interacting matter. We find that a strong asymmetry is generated in central lead-lead reactions that has little sensitivity to the fluctuations of the underlying soft hadronic background. We present theoretical model predictions for its shape and magnitude.

  2. The effects of wing flexibility on the flight performance and stability of flapping wing micro air vehicles

    Science.gov (United States)

    Bluman, James Edward

    Insect wings are flexible. However, the influence of wing flexibility on the flight dynamics of insects and flapping wing micro air vehicles is unknown. Most studies in the literature consider rigid wings and conclude that the hover equilibrium is unstable. This dissertation shows that a flapping wing flyer with flexible wings exhibits stable natural modes of the open loop system in hover, never reported before. The free-flight insect flight dynamics is modeled for both flexible and rigid wings. Wing mass and inertia are included in the nonlinear equations of motion. The flapping wing aerodynamics are modeled using a quasi-steady model, a well-validated two dimensional Navier Stokes model, and a coupled, two dimensional Navier Stokes - Euler Bernoulli beam model that accurately models the fluid-structure interaction of flexible wings. Hover equilibrium is systematically and efficiently determined with a coupled quasi-steady and Navier-Stokes equation trimmer. The power and stability are reported at hover while parametrically varying the pitch axis location for rigid wings and the structural stiffness for flexible wings. The results indicate that the rigid wings possess an unstable oscillatory mode mainly due to their pitch sensitivity to horizontal velocity perturbations. The flexible wings stabilize this mode primarily by adjusting their wing shape in the presence of perturbations. The wing's response to perturbations generates significantly more horizontal velocity damping and pitch rate damping than in rigid wings. Furthermore, the flexible wings experience substantially less wing wake interaction, which, for rigid wings, is destabilizing. The power required to hover a fruit fly with actively rotating rigid wings varies between 16.9 and 34.2 W/kg. The optimal power occurs when the pitch axis is located at 30% chord, similar to some biological observations. Flexible wings require 23.1 to 38.5 W/kg. However, flexible wings exhibit more stable system dynamics and

  3. Universal fluctuations in orbital diamagnetism

    Science.gov (United States)

    Pal, P. S.; Saha, Arnab; Jayannavar, A. M.

    2018-03-01

    Bohr-van Leuween theorem has attracted the notice of physicists for more than 100 years. The theorem states about the absence of magnetisation in classical systems in thermal equilibrium. In this paper, we discuss about fluctuations of magnetic moment in classical systems. In recent years, this topic has been investigated intensively and it is not free from controversy. We have considered a system consisting of a single particle moving in a plane. A magnetic field is applied perpendicular to the plane. The system is in contact with a thermal bath. We have considered three cases: (a) particle moving in a homogeneous medium, (b) particle moving in a medium with space-dependent friction and (c) particle moving in a medium with space-dependent temperature. For all the three cases, the average magnetic moment and fluctuations in magnetic moment have been calculated. Average magnetic moment saturates to a finite value in the case of free particle but goes to zero when the particle is confined by a 2D harmonic potential. Fluctuations in magnetic moment shows universal features in the presence of arbitrary friction inhomogeneity. For this case, the system reaches equilibrium asymptotically. In the case of space-dependent temperature profile, the stationary distribution is non-Gibbsian and fluctuations deviate from universal value for the bounded system only.

  4. Universal fluctuations in orbital diamagnetism

    Indian Academy of Sciences (India)

    P S Pal

    2018-01-31

    Jan 31, 2018 ... Indian Academy of Sciences https://doi.org/10.1007/s12043-018-1521-5. Universal fluctuations ... dissertation almost a century ago. They had shown that in the presence of constant magnetic field ..... Ph.D. Thesis (Indian Institute of Science, Bengaluru,. 1982). [7] N Kumar and K Vijay Kumar, Europhys. Lett.

  5. Fluctuating hydrodynamics for ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Lazaridis, Konstantinos [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States); Wickham, Logan [Department of Computer Science, Washington State University, Richland, 99354 (United States); Voulgarakis, Nikolaos, E-mail: n.voulgarakis@wsu.edu [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States)

    2017-04-25

    We present a mean-field fluctuating hydrodynamics (FHD) method for studying the structural and transport properties of ionic liquids in bulk and near electrified surfaces. The free energy of the system consists of two competing terms: (1) a Landau–Lifshitz functional that models the spontaneous separation of the ionic groups, and (2) the standard mean-field electrostatic interaction between the ions in the liquid. The numerical approach used to solve the resulting FHD-Poisson equations is very efficient and models thermal fluctuations with remarkable accuracy. Such density fluctuations are sufficiently strong to excite the experimentally observed spontaneous formation of liquid nano-domains. Statistical analysis of our simulations provides quantitative information about the properties of ionic liquids, such as the mixing quality, stability, and the size of the nano-domains. Our model, thus, can be adequately parameterized by directly comparing our prediction with experimental measurements and all-atom simulations. Conclusively, this work can serve as a practical mathematical tool for testing various theories and designing more efficient mixtures of ionic liquids. - Highlights: • A new fluctuating hydrodynamics method for ionic liquids. • Description of ionic liquid morphology in bulk and near electrified surfaces. • Direct comparison with experimental measurements.

  6. Fluctuation relation for heat engines

    International Nuclear Information System (INIS)

    Sinitsyn, N A

    2011-01-01

    We derive the exact equality, referred to as the fluctuation relation for heat engines (FRHE), that relates statistics of heat extracted from one of the two heat baths and the work per one cycle of a heat engine operation. Carnot's inequality of classical thermodynamics follows as a direct consequence of the FRHE. (paper)

  7. Reaction rates when barriers fluctuate

    OpenAIRE

    Reimann, Peter

    1999-01-01

    Reaction rates when barriers fluctuate : a path integral approach / P. Hänggi and P. Reimann. - In: International Conference on Path Integrals from peV to TeV : Proceedings of the ... / eds.: R. Casalbuoni ... - Singapore u.a. : World Scientific, 1999. - S. 407-409

  8. Fluctuation conductivity in cuprate superconductors

    Indian Academy of Sciences (India)

    model to be inadequate to describe the fluctuation conductivity in these materials. The modification ... shown by various models which consider several conducting layers per unit cell, with ei- ther interlayer or ..... Pomer et al [6] have observed a large discrepancy of their data measured at 1 tesla from the prediction of eq. (1).

  9. Kondo effect and mesoscopic fluctuations

    Indian Academy of Sciences (India)

    Slave boson/fermion mean-field approach. A complete solution of this problem would presumably involve developing a Fermi liquid theory 'à la Nozières' [15] taking properly into account the mesoscopic fluctuations. A first step in this direction is to use a mean-field treatment based on the slave boson/fermion technique [1] ...

  10. Inflation Asymmetry and Menu Costs - New Micro Data Evidence

    OpenAIRE

    Adam Reiff; Peter Karadi

    2009-01-01

    evidence on the asymmetry of inflation response to aggregate shocks. We show that even though a standard menu cost model like that of Golosov and Lucas (2007) underestimates the asymmetry, a sectoral menu cost model with multi-product firms and trend-inflation can quantitatively account for the inflation asymmetry observed in the data, thereby it provides direct evidence to the argument of Ball and Mankiw (1994). The model predicts that the effect of a positive monetary policy shock can have ...

  11. Contract Design: The problem of information asymmetry.

    Science.gov (United States)

    Mühlbacher, Axel C; Amelung, Volker E; Juhnke, Christin

    2018-01-12

    Integrated care systems are advocated as an effective method of improving the performance of healthcare systems. These systems outline a payment and care delivery model that intends to tie provider reimbursements to predefined quality metrics. Little is known about the contractual design and the main challenges of delegating "accountability" to these new kinds of organisations and/or contracts. The research question in this article focuses on how healthcare contracts can look like and which possible problems arise in designing such contracts. In this a special interest is placed on information asymmetries. A comprehensive literature review on methods of designing contracts in Integrated Care was conducted. This article is the first in a row of three that all contribute to a specific issue in designing healthcare contracts. Starting with the organisation of contracts and information asymmetries, part 2 focusses on financial options and risks and part 3 finally concludes with the question of risk management and evaluation. Healthcare contracting between providers and payers will have a major impact on the overall design of future healthcare systems. If Integrated care systems or any other similar concept of care delivery are to be contracted directly by payers to manage the continuum of care the costs of market utilisation play an essential role. Transaction costs also arise in the course of the negotiation and implementation of contracts. These costs are the reason why it is generally not possible to conclude perfect (complete) contracts. Problems with asymmetric distribution of information can relate to the situation before a contract is concluded (adverse selection) and after conclusion of a contract (moral hazard). Information asymmetries are seen as a major obstacle to the efficient operation of integrated care programmes. Coordination and motivation problems cannot be solved at no-costs. The presented problems in the design of selective individual contracts

  12. Asymmetry overlay correction for lithography processes

    Science.gov (United States)

    Chen, Ming-Jui; Yu, Chun-Chi; Weng, Tang Chun; Chang, C.-H.; Chen, Charlie; Lin, Chia Ching; Lio, En Chuan; Yu, Chia Hsiang

    2017-03-01

    Overlay control for semiconductor devices is getting tighter in recent years. In the past, we may only concern the whether the overlay are in spec or not. However, the spec we concerned was the same for both X and Y directions. To achieve the tighter spec in the future, we may consider the asymmetry specs for X and Y directions separately for some specific layers, such as CONT layer. For example, if the spec of X direction is tighter than Y direction, we can lose the precision of overlay from Y direction to let overlay from X direction more precise. Theoretically, the common overlay models such as HOPC or iHOPC set X and Y directions independently. To reach the goal of loss overly from one direction to preserve the overlay from the other direction, we consider the full map measurement overlay historical data. From these data, we can analyze the data to find which overlay targets are more important to X direction, and we can set these corresponding targets as the new measurement locations. This is one concept of "asymmetry" since the chosen measurement locations can provide more precisely correction for the overlay of specific direction. On the other hand, we use the in spec ratio (ISR) index for all measurement overlay targets on wafer to replace the traditional mean plus 3 sigma (M3S) index, since we have the budgets of both X and Y directions. The in spec ratio is defined as ratio that the residuals of X and Y directions fill the corresponding budgets, simultaneously. Since our goal is to maximize the ISR, the traditional M3S optimization algorithm can be replaced by ISR optimization with different overlay specs. That is the reason we call "asymmetry overlay correction".

  13. Symmetry and Asymmetry in Bouncing Gaits

    Directory of Open Access Journals (Sweden)

    Giovanni A. Cavagna

    2010-06-01

    Full Text Available In running, hopping and trotting gaits, the center of mass of the body oscillates each step below and above an equilibrium position where the vertical force on the ground equals body weight. In trotting and low speed human running, the average vertical acceleration of the center of mass during the lower part of the oscillation equals that of the upper part, the duration of the lower part equals that of the upper part and the step frequency equals the resonant frequency of the bouncing system: we define this as on-offground symmetric rebound. In hopping and high speed human running, the average vertical acceleration of the center of mass during the lower part of the oscillation exceeds that of the upper part, the duration of the upper part exceeds that of the lower part and the step frequency is lower than the resonant frequency of the bouncing system: we define this as on-off-ground asymmetric rebound. Here we examine the physical and physiological constraints resulting in this on-off-ground symmetry and asymmetry of the rebound. Furthermore, the average force exerted during the brake when the body decelerates downwards and forwards is greater than that exerted during the push when the body is reaccelerated upwards and forwards. This landing-takeoff asymmetry, which would be nil in the elastic rebound of the symmetric spring-mass model for running and hopping, suggests a less efficient elastic energy storage and recovery during the bouncing step. During hopping, running and trotting the landing-takeoff asymmetry and the mass-specific vertical stiffness are smaller in larger animals than in the smaller animals suggesting a more efficient rebound in larger animals.

  14. Irreversibility and complex network behavior of stream flow fluctuations

    Science.gov (United States)

    Serinaldi, Francesco; Kilsby, Chris G.

    2016-05-01

    Exploiting the duality between time series and networks, directed horizontal visibility graphs (DHVGs) are used to perform an unprecedented analysis of the dynamics of stream flow fluctuations with focus on time irreversibility and long range dependence. The analysis relies on a large quality-controlled data set consisting of 699 daily time series recorded in the continental United States (CONUS) that are not affected by human activity and primarily reflects meteorological conditions. DHVGs allow a clear visualization and quantification of time irreversibility of flow dynamics, which can be interpreted as a signature of nonlinearity, and long range dependence resulting from the interaction of atmospheric, surface and underground processes acting at multiple spatio-temporal scales. Irreversibility is explored by mapping the time series into ingoing, outgoing, and undirected graphs and comparing the corresponding degree distributions. Using surrogate data preserving up to the second order linear temporal dependence properties of the observed series, DHVGs highlight the additional complexity introduced by nonlinearity into flow fluctuation dynamics. We show that the degree distributions do not decay exponentially as expected, but tend to follow a subexponential behavior, even though sampling uncertainty does not allow a clear distinction between apparent or true power law decay. These results confirm that the complexity of stream flow dynamics goes beyond a linear representation involving for instance the combination of linear processes with short and long range dependence, and requires modeling strategies accounting for temporal asymmetry and nonlinearity.

  15. Modified Feynman ratchet with velocity-dependent fluctuations

    Directory of Open Access Journals (Sweden)

    Jack Denur

    2004-03-01

    Full Text Available Abstract: The randomness of Brownian motion at thermodynamic equilibrium can be spontaneously broken by velocity-dependence of fluctuations, i.e., by dependence of values or probability distributions of fluctuating properties on Brownian-motional velocity. Such randomness-breaking can spontaneously obtain via interaction between Brownian-motional Doppler effects --- which manifest the required velocity-dependence --- and system geometrical asymmetry. A non random walk is thereby spontaneously superposed on Brownian motion, resulting in a systematic net drift velocity despite thermodynamic equilibrium. The time evolution of this systematic net drift velocity --- and of velocity probability density, force, and power output --- is derived for a velocity-dependent modification of Feynman's ratchet. We show that said spontaneous randomness-breaking, and consequent systematic net drift velocity, imply: bias from the Maxwellian of the system's velocity probability density, the force that tends to accelerate it, and its power output. Maximization, especially of power output, is discussed. Uncompensated decreases in total entropy, challenging the second law of thermodynamics, are thereby implied.

  16. Top quark asymmetry and dijet resonances

    CERN Document Server

    Jung, Sunghoon; Wells, James D.

    2011-01-01

    CDF recently reported an anomaly in the $m_{jj}$ distribution of dijet events produced in association with a $W$ boson. If this anomaly is associated with a new flavor conserving vector resonance, $V$, one might have expected to observe effects in the analogous $m_{jj}$ distribution produced in association with a $\\gamma$. No such excess is observed. A single $u-t-V$ flavor changing coupling, however, can contribute to the $m_{jj}$ anomaly while being consistent with other resonance searches. Furthermore, it gives a potential explanation of the observed forward-backward asymmetry in top quark production.

  17. General Equilibrium Pricing with Information Asymmetry

    Directory of Open Access Journals (Sweden)

    Yuzhong eZhang

    2015-08-01

    Full Text Available We propose a general equilibrium model for asset pricing that incorporates asymmetric information as the key element determining security prices. In our setting, the concepts of completeness, arbitrage, state price and equivalent martingale measure are extended to the case of asymmetric information. Our model shows that in a so-called quasi-complete market, the agents with differential information can reach an agreement on an universal equilibrium price. The corresponding state price and martingale measure are determined. The key intuition is that agents evaluate consumption choices conditioned on their private information and the public information generated by price. As a consequence, information asymmetry can lead to mispricing as well.

  18. [Asymmetry of antennal grooming in the cockroach (Periplaneta americana)].

    Science.gov (United States)

    2014-07-01

    The present study was conducted to determine the key features of antennal grooming of male American cockroaches in neutral circumstances. It was shown for the first time that the right antenna was cleaned significantly more often than the left one, which indicates the presence of functional asymmetry of antennal grooming in this insect species. At the same time, no statistically significant asymmetry was found for grooming of antennal bases and legs. Morphological asymmetries of antennae and legs and/or brain lateralization are the plausible sources of observed behavioral asymmetry in antennal grooming.

  19. Receptivity to Kinetic Fluctuations: A Multiple Scales Approach

    Science.gov (United States)

    Edwards, Luke; Tumin, Anatoli

    2017-11-01

    The receptivity of high-speed compressible boundary layers to kinetic fluctuations (KF) is considered within the framework of fluctuating hydrodynamics. The formulation is based on the idea that KF-induced dissipative fluxes may lead to the generation of unstable modes in the boundary layer. Fedorov and Tumin solved the receptivity problem using an asymptotic matching approach which utilized a resonant inner solution in the vicinity of the generation point of the second Mack mode. Here we take a slightly more general approach based on a multiple scales WKB ansatz which requires fewer assumptions about the behavior of the stability spectrum. The approach is modeled after the one taken by Luchini to study low speed incompressible boundary layers over a swept wing. The new framework is used to study examples of high-enthalpy, flat plate boundary layers whose spectra exhibit nuanced behavior near the generation point, such as first mode instabilities and near-neutral evolution over moderate length scales. The configurations considered exhibit supersonic unstable second Mack modes despite the temperature ratio Tw /Te > 1 , contrary to prior expectations. Supported by AFOSR and ONR.

  20. [Wing 1 radiation survey and contamination report

    International Nuclear Information System (INIS)

    Olsen, K.

    1991-01-01

    We have completed the 5480.11 survey for Wing 1. All area(s)/item(s) requested by the 5480.11 committee have been thoroughly surveyed and documented. Decontamination/disposal of contaminated items has been accomplished. The wing 1 survey was started on 8/13/90 and completed 9/18/90. However, the follow-up surveys were not completed until 2/18/91. We received the final set of smear samples for wing 1 on 1/13/91. A total of 5,495 smears were taken from wing 1 and total of 465 smears were taken during the follow-up surveys. There were a total 122 items found to have fixed contamination and 4 items with smearable contamination in excess of the limits specified in DOE ORDER 5480.11 (AR 3-7). The following area(s)/item(s) were not included in the 5480.11 survey: Hallways, Access panels, Men's and women's change rooms, Janitor closets, Wall lockers and item(s) stored in wing 1 hallways and room 1116. If our contract is renewed, we will include those areas in our survey according to your request of April 15, 1991

  1. Flapping wing aerodynamics: from insects to vertebrates.

    Science.gov (United States)

    Chin, Diana D; Lentink, David

    2016-04-01

    More than a million insects and approximately 11,000 vertebrates utilize flapping wings to fly. However, flapping flight has only been studied in a few of these species, so many challenges remain in understanding this form of locomotion. Five key aerodynamic mechanisms have been identified for insect flight. Among these is the leading edge vortex, which is a convergent solution to avoid stall for insects, bats and birds. The roles of the other mechanisms - added mass, clap and fling, rotational circulation and wing-wake interactions - have not yet been thoroughly studied in the context of vertebrate flight. Further challenges to understanding bat and bird flight are posed by the complex, dynamic wing morphologies of these species and the more turbulent airflow generated by their wings compared with that observed during insect flight. Nevertheless, three dimensionless numbers that combine key flow, morphological and kinematic parameters - the Reynolds number, Rossby number and advance ratio - govern flapping wing aerodynamics for both insects and vertebrates. These numbers can thus be used to organize an integrative framework for studying and comparing animal flapping flight. Here, we provide a roadmap for developing such a framework, highlighting the aerodynamic mechanisms that remain to be quantified and compared across species. Ultimately, incorporating complex flight maneuvers, environmental effects and developmental stages into this framework will also be essential to advancing our understanding of the biomechanics, movement ecology and evolution of animal flight. © 2016. Published by The Company of Biologists Ltd.

  2. Otolith mass asymmetry: natural, and after weightlessness and hypergravity

    Science.gov (United States)

    Lychakov, Dmitri

    It is believed that otolith mass asymmetry (OA) can play an essential role in genesis of vestibular space disturbances in human subjects and fish. This review poster presents data on values and characters of OA in animals of various species and classes and on the effect of weightlessness and hypergravity on OA; the issue of the effect of OA on vestibular and auditory functions also is considered (Lychakov, Rebane, 2004, 2005; Lychakov et al., 2006, 2008). In symmetric vertebrates, OA was shown to be fluctuating, its coefficient chiχ ranges from - 0.2 to + 0.2 (±± 20%). It should be stressed that in the overwhelming majority of individuals absolute values of chiχ otolith organs to work in coordination; this is why the OA level is equally low regardless of the individual taxonomic and ecological position, size, age, and otolith growth rate. Individuals with the abnormally high OA level can experience difficulties in analyzing auditory and vestibular stimuli; therefore, most of such individuals are eliminated by natural selection. Unlike symmetric vertebrates, labyrinths of many Pleuronectiformes have pronounced OA. Otoliths in the lower labyrinth, on average, are significantly heavier than those in the upper labyrinth. The organs of flatfish represent the only example when OA, being directional, seem to play an essential role in lateralized behavior and are suggested to be used in the spatial localization of the source of sound. The short-term weightlessness and relatively weak hypergravity (> 3g as well as some diseases and age-related changes can indirectly enhance OA and cause some functional disturbances. This work was partly supported by Russian grant RFFI 14-04-00601.

  3. Experimental investigation of transverse spin asymmetries in muon-p SIDIS processes: Collins asymmetries

    CERN Document Server

    Adolph, C.; Alexakhin, V.Yu.; Alexandrov, Yu.; Alexeev, G.D.; Amoroso, A.; Antonov, A.A.; Austregesilo, A.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Bedfer, Y.; Bernhard, J.; Bertini, R.; Bettinelli, M.; Bicker, K.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Braun, C.; Bravar, A.; Bressan, A.; Burtin, E.; Capozza, L.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Crespo, M.L.; Dalla Torre, S.; Das, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Duic, V.; Dunnweber, W.; Dziewiecki, M.; Efremov, A.; Elia, C.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Fischer, H.; Franco, C.; von Hohenesche, N.du Fresne; Friedrich, J.M.; Frolov, V.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Goertz, S.; Grabmuller, S.; Grasso, A.; Grube, B.; Gushterski, R.; Guskov, A.; Guthorl, T.; Haas, F.; von Harrach, D.; Heinsius, F.H.; Herrmann, F.; Hess, C.; Hinterberger, F.; Horikawa, N.; Hoppner, Ch.; d'Hose, N.; Ishimoto, S.; Ivanov, O.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Joosten, R.; Kabuss, E.; Kang, D.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Korzenev, A.; Kotzinian, A.M.; Kouznetsov, O.; Kramer, M.; Kroumchtein, Z.V.; Kunne, F.; Kurek, K.; Lauser, L.; Lednev, A.A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Liska, T.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G.K.; Mann, A.; Marchand, C.; Martin, A.; Marzec, J.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu.V.; Moinester, M.A.; Morreale, A.; Mutter, A.; Nagaytsev, A.; Nagel, T.; Negrini, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.I.; Nowak, W.D.; Nunes, A.S.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Perevalova, E.; Pesaro, G.; Peshekhonov, D.V.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Rajotte, J.F.; Ramos, S.; Rapatsky, V.; Reicherz, G.; Richter, A.; Rocco, E.; Rondio, E.; Rossiyskaya, N.S.; Ryabchikov, D.I.; Samoylenko, V.D.; Sandacz, A.; Sapozhnikov, M.G.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schluter, T.; Schmidt, K.; Schmitt, L.; Schonning, K.; Schopferer, S.; Schott, M.; Schroder, W.; Shevchenko, O.Yu.; Silva, L.; Sinha, L.; Sissakian, A.N.; Slunecka, M.; Smirnov, G.I.; Sosio, S.; Sozzi, F.; Srnka, A.; Steiger, L.; Stolarski, M.; Sulc, M.; Sulej, R.; Suzuki, H.; Sznajder, P.; Takekawa, S.; Wolbeek, J.Ter; Tessaro, S.; Tessarotto, F.; Tkatchev, L.G.; Uhl, S.; Uman, I.; Vandenbroucke, M.; Virius, M.; Vlassov, N.V.; Wang, L.; Wilfert, M.; Windmolders, R.; Wislicki, W.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zhuravlev, N.; Zvyagin, A.

    2012-10-31

    The COMPASS Collaboration at CERN has measured the transverse spin azimuthal asymmetry of charged hadrons produced in semi-inclusive deep inelastic scattering using a 160 GeV positive muon beam and a transversely polarised NH_3 target. The Collins asymmetry of the proton was extracted in the Bjorken x range 0.003asymmetries for negative and positive hadrons are similar in magnitude and opposite in sign. They are compatible with model calculations in which the u-quark transversity is opposite in sign and somewhat larger than the d-quark transversity distribution function. The asymmetry is extracted as a function of Bjorken $x$, the relative hadron energy $z$ and the hadron transverse momentum p_T^h. The high statistics and quality of the data also allow for more detailed investigations of the dependence on the ki...

  4. Principle of bio-inspired insect wing rotational hinge design

    Science.gov (United States)

    Fei, Fan

    A principle for designing and fabricating bio-inspired miniature artificial insect flapping wing using flexure rotational hinge design is presented. A systematic approach of selecting rotational hinge stiffness value is proposed. Based on the understanding of flapping wing aerodynamics, a dynamic simulation is constructed using the established quasi-steady model and the wing design. Simulations were performed to gain insight on how different parameters affect the wing rotational response. Based on system resonance a model to predict the optimal rotational hinge stiffness based on given wing parameter and flapping wing kinematic is proposed. By varying different wing parameters, the proposed method is shown to be applicable to a wide range of wing designs with different sizes and shapes. With the selected hinge stiffness value, aspects of the rotational joint design is discussed and an integrated wing-hinge structure design using laminated carbon fiber and polymer film is presented. Manufacturing process of such composite structure is developed to achieve high accuracy and repeatability. The yielded hinge stiffness is verified by measurements. To validate the proposed model, flapping wing experiments were conducted. A flapping actuation set up is built using DC motor and a controller is implemented on a microcontroller to track desired wing stroke kinematic. Wing stroke and rotation kinematic were extracted using a high speed camera and the lift generation is evaluated. A total of 49 flapping experiments were presented, experimental data shows good correlation with the model's prediction. With the wing rotational hinge stiffness designed so that the rotational resonant frequency is twice as the stroke frequency, the resulting wing rotation generates near optimal lift. With further simulation, the proposed model shows low sensitivity to wing parameter variation. As a result, giving a design parameter of a flapping wing robot platform, the proposed principle can

  5. Gliding swifts attain laminar flow over rough wings.

    Directory of Open Access Journals (Sweden)

    David Lentink

    Full Text Available Swifts are among the most aerodynamically refined gliding birds. However, the overlapping vanes and protruding shafts of their primary feathers make swift wings remarkably rough for their size. Wing roughness height is 1-2% of chord length on the upper surface--10,000 times rougher than sailplane wings. Sailplanes depend on extreme wing smoothness to increase the area of laminar flow on the wing surface and minimize drag for extended glides. To understand why the swift does not rely on smooth wings, we used a stethoscope to map laminar flow over preserved wings in a low-turbulence wind tunnel. By combining laminar area, lift, and drag measurements, we show that average area of laminar flow on swift wings is 69% (n = 3; std 13% of their total area during glides that maximize flight distance and duration--similar to high-performance sailplanes. Our aerodynamic analysis indicates that swifts attain laminar flow over their rough wings because their wing size is comparable to the distance the air travels (after a roughness-induced perturbation before it transitions from laminar to turbulent. To interpret the function of swift wing roughness, we simulated its effect on smooth model wings using physical models. This manipulation shows that laminar flow is reduced and drag increased at high speeds. At the speeds at which swifts cruise, however, swift-like roughness prolongs laminar flow and reduces drag. This feature gives small birds with rudimentary wings an edge during the evolution of glide performance.

  6. The role of wing kinematics of freely flying birds downstream the wake of flapping wings

    Science.gov (United States)

    Krishnan, Krishnamoorthy; Gurka, Roi

    2016-11-01

    Avian aerodynamics has been a topic of research for centuries. Avian flight features such as flapping, morphing and maneuvering make bird aerodynamics a complex system to study, analyze and understand. Aerodynamic performance of the flapping wings can be quantified by measuring the vortex structures present in the downstream wake. Still, the direct correlation between the flapping wing kinematics and the evolution of wake features need to be established. In this present study, near wake of three bird species (western sandpiper, European starling and American robin) have been measured experimentally. Long duration, time-resolved, particle image velocimetry technique has been used to capture the wake properties. Simultaneously, the bird kinematics have been captured using high speed camera. Wake structures are reconstructed from the collected PIV images for long chord distances downstream. Wake vorticities and circulation are expressed in the wake composites. Comparison of the wake features of the three birds shows similarities and some key differences are also found. Wing tip motions of the birds are extracted for four continuous wing beat cycle to analyze the wing kinematics. Kinematic parameters of all the three birds are compared to each other and similar trends exhibited by all the birds have been observed. A correlation between the wake evolutions with the wing motion is presented. It was found that the wings' motion generates unique flow patterns at the near wake, especially at the transition phases. At these locations, a drastic change in the circulation was observed.

  7. Investigating the Force Production of Functionally-Graded Flexible Wings in Flapping Wing Flight

    Science.gov (United States)

    Mudbhari, Durlav; Erdogan, Malcolm; He, Kai; Bateman, Daniel; Lipkis, Rory; Moored, Keith

    2015-11-01

    Birds, insects and bats oscillate their wings to propel themselves over long distances and to maneuver with unprecedented agility. A key element to achieve their impressive aerodynamic performance is the flexibility of their wings. Numerous studies have shown that homogeneously flexible wings can enhance force production, propulsive efficiency and lift efficiency. Yet, animal wings are not homogenously flexible, but instead have varying material properties. The aim of this study is to characterize the force production and energetics of functionally-graded flexible wings. A partially-flexible wing composed of a rigid section and a flexible section is used as a first-order model of functionally-graded materials. The flexion occurs in the spanwise direction and it is affected by the spanwise flexion ratio, that is, the ratio of the length of the rigid section compared to the total span length. By varying the flexion ratio as well as the material properties of the flexible section, the study aims to examine the force production and energetics of flapping flight with functionally-graded flexible wings. Supported by the Office of Naval Research under Program Director Dr. Bob Brizzolara, MURI grant number N00014-14-1-0533.

  8. Aeroelastic Analysis of Modern Complex Wings

    Science.gov (United States)

    Kapania, Rakesh K.; Bhardwaj, Manoj K.; Reichenbach, Eric; Guruswamy, Guru P.

    1996-01-01

    A process is presented by which aeroelastic analysis is performed by using an advanced computational fluid dynamics (CFD) code coupled with an advanced computational structural dynamics (CSD) code. The process is demonstrated on an F/A-18 Stabilator using NASTD (an in-house McDonnell Douglas Aerospace East CFD code) coupled with NASTRAN. The process is also demonstrated on an aeroelastic research wing (ARW-2) using ENSAERO (an in-house NASA Ames Research Center CFD code) coupled with a finite element wing-box structures code. Good results have been obtained for the F/A-18 Stabilator while results for the ARW-2 supercritical wing are still being obtained.

  9. Asymmetry parameter for nonmesonic hypernuclear decay

    International Nuclear Information System (INIS)

    Barbero, Cesar; Galeao, Alfredo P.; Krmpotic, Francisco

    2005-01-01

    We give general expressions for the vector asymmetry in the angular distribution of protons in the nonmesonic weak decay of polarized hypernuclei. From these we derive an explicit expression for the calculation of the asymmetry parameter, a Λ , which is applicable to the specific cases of Λ 5 He and Λ 12 C described within the extreme shell model. In contrast to the approximate formula widely used in the literature, it includes the effects of three-body kinematics in the final states of the decay and correctly treats the contribution of transitions originating from single-proton states beyond the s-shell. This expression is then used for the corresponding numerical computation of a Λ within several one-meson-exchange models. Besides the strictly local approximation usually adopted for the transition potential, we also consider the addition of the first-order nonlocality terms. We find values for a Λ ranging from -0.62 to -0.24, in qualitative agreement with other theoretical estimates but in contradiction with some recent experimental determinations

  10. On Introducing Asymmetry into Circular Distributions

    Directory of Open Access Journals (Sweden)

    Dale Umbach

    2012-07-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif";} We give a brief history of the results which led to the introduction of asymmetry into symmetric circular distributions. This is followed by the presentation of another method of introducing asymmetry. Some properties of the induced distributions are studied. Finally, this new distribution is shown to be a reasonable fit to the Jander ant data as presented in Fisher (1993.

  11. LOWER LIMB ASYMMETRIES IN RHYTHMIC GYMNASTICS ATHLETES.

    Science.gov (United States)

    Frutuoso, Anderson Simas; Diefenthaeler, Fernando; Vaz, Marco Aurélio; Freitas, Cintia de la Rocha

    2016-02-01

    Different limb training demands and limb preference may determine anthropometric and muscle force inter-limb asymmetries in Rhythmic Gymnastics (RG) athletes. The purpose of this study was to evaluate the influence of lateral preference of the lower extremity on anthropometric, range of motion, and isokinetic torque measurements of RG athletes. Cross sectional study. Lower limb anthropometric measurements (girth, estimated anatomical cross-sectional area), hip, knee and ankle range of motion, flexor and extensor isokinetic torques (angular velocities = 60, 180, e 240 °·s(-1)) and bilateral asymmetry index were evaluated in 11 international level Rhythmic Gymnastics athletes (17.9 ± 4.0 years of age; 9.1 ± 5,1 years of experience; 26.8 ± 6.0 weekly training hours). The preferred limb showed larger thigh girth and anatomical cross-sectional area, higher ankle dorsiflexor range of motion, higher hip flexor torque at 60 °·s(-1) and higher plantarflexor torque at 180 °·s(-1) compared to the non-preferred limb. The observed differences seem to be strictly related to lateral preference and rhythmic gymnastics training. 3.

  12. Perceptual asymmetries and handedness: A neglected link?

    Directory of Open Access Journals (Sweden)

    Daniele eMarzoli

    2014-02-01

    Full Text Available Healthy individuals tend to weigh in more the left than the right side of visual space in a variety of contexts, ranging from pseudoneglect to perceptual asymmetries for faces. Among the common explanations proposed for the attentional and perceptual advantages of the left visual field, a link with the prevalence of right-handedness in humans has never been suggested, although some evidence seems to converge in favor of a bias of spatial attention towards the region most likely coincident with another person’s right hand during a face-to-face interaction. Such a bias might imply an increased efficiency in monitoring both communicative and aggressive acts, the right limb being more used than the left in both types of behaviour. Although attentional and perceptual asymmetries could be linked to right-handedness at the level of phylogeny because of the evolutionarily advantage of directing attention towards the region where others’ dominant hand usually operates, it is also legitimate to question whether, at the ontogenetic level, frequent exposure to right-handed individuals may foster leftward biases. These views are discussed in the light of extant literature, and a number of tests are proposed in order to assess our hypotheses.

  13. Single transverse spin asymmetry of forward neutrons

    International Nuclear Information System (INIS)

    Kopeliovich, B. Z.; Potashnikova, I. K.; Schmidt, Ivan; Soffer, J.

    2011-01-01

    We calculate the single transverse spin asymmetry A N (t), for inclusive neutron production in pp collisions at forward rapidities relative to the polarized proton in the energy range of RHIC. Absorptive corrections to the pion pole generate a relative phase between the spin-flip and nonflip amplitudes, leading to a transverse spin asymmetry which is found to be far too small to explain the magnitude of A N observed in the PHENIX experiment. A larger contribution, which does not vanish at high energies, comes from the interference of pion and a 1 -Reggeon exchanges. The unnatural parity of a 1 guarantees a substantial phase shift, although the magnitude is strongly suppressed by the smallness of diffractive πp→a 1 p cross section. We replace the Regge a 1 pole by the Regge cut corresponding to the πρ exchange in the 1 + S state. The production of such a state, which we treat as an effective pole a, forms a narrow peak in the 3π invariant mass distribution in diffractive πp interactions. The cross section is large, so one can assume that this state saturates the spectral function of the axial current and we can determine its coupling to nucleons via the partially conserved axial-vector-current constraint Goldberger-Treiman relation and the second Weinberg sum rule. The numerical results of the parameter-free calculation of A N are in excellent agreement with the PHENIX data.

  14. Asymmetries in four powerful radio sources

    International Nuclear Information System (INIS)

    Lonsdale, C.J.; Morison, I.

    1983-01-01

    The extragalactic radio sources 3C 153, 196, 249.1 and 268.4 have been observed at frequencies of 408 and 1666 MHz with the new MERLIN array operated by Jodrell Bank, giving resolutions of approx. 0.9 and 0.25 arcsec respectively. The sources show marked asymmetries about the central object in spectral index, flux and morphology, which we believe are most naturally accounted for by the effects of a time-dependent asymmetry in the central powerhouse. In the case of 3C 249.1 the observations suggest that energy is being supplied alternately to the two sides of the source. The 1666-MHz observations also show that each of the other three sources contains one extremely compact hotspot. The minimum internal energy densities in these hotspots are such that confinement by ram pressure of motion through the intergalactic medium may not be possible, indicating that such features are transient phenomena in free expansion, or that some other confinement mechanism is operating. (author)

  15. Etik og ansvar, symmetri eller asymmetri ?

    DEFF Research Database (Denmark)

    Nørgaard, Britta

    2014-01-01

    Når professionelle relationer, hvor fysioterapeuter, pædagoger, lærere, sygeplejersker optræder, omtales, dukker begrebet symmetri og asymmetri op. Oftest omtales den professionelle relation som asymmetrisk, hvor det næsten implicit og uden for diskussion forstås, at det er den professionelle, der...... har den mest magtfulde position. Med filosoffen Emmanuel Lévinas udfordres denne selvfølgelighed, og jeg vil med artiklen gerne bidrage til at udfordre den selvfølgelighed, hvormed overvejelser om symmetri og asymmetri ofte udtales i relation til det borgerrettede professionelle arbejde. Mange...... fordring, som ikke er noget vi kan undslå os eller bestemme os for, men som er noget der overgår os, og dermed vil den andens liv til dels ligge i vores hænder. Buber omtales ofte som mødets filosof, og for ham er det centrale, at vi i mødet ikke gør den anden til et ”det”, og hans mest kendte værk hedder...

  16. Active Twist Control for a Compliant Wing Structure, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Blended wing body (BWB) aircraft provide an aerodynamically superior solution over traditional tube-and-wing designs for a number of mission profiles. These...

  17. Fixed-Wing Micro Air Vehicles with Hovering Capabilities

    National Research Council Canada - National Science Library

    Bataille, Boris; Poinsot, Damien; Thipyopas, Chinnapat; Moschetta, Jean-Marc

    2007-01-01

    Fixed-wing micro air vehicles (MAV) are very attractive for outdoor surveillance missions since they generally offer better payload and endurance capabilities than rotorcraft or flapping-wing vehicles of equal size...

  18. Nonlinear Dynamics of Wind Turbine Wings

    DEFF Research Database (Denmark)

    Larsen, Jesper Winther

    Wind turbines with a nominal effect of 5MW with a rotor diameter of up to 126m are produced today. With the increasing size wind turbines also become more and more optimized with respect to structural dimensions and material usage, without increasing the stiffness proportionally. Consequently......, large wind turbines become increasingly flexible and dynamically sensitive. This project focuses on the structural analysis of highly flexible wind turbine wings, and the aerodynamic loading of wind turbine wings under large changes in flow field due to elastic deformations and changing wind conditions....

  19. Stability and transition on swept wings

    Science.gov (United States)

    Stuckert, Greg; Herbert, Thorwald; Esfahanian, Vahid

    1993-01-01

    This paper describes the extension and application of the Parabolized Stability Equations (PSE) to the stability and transition of the supersonic three-dimensional laminar boundary layer on a swept wing. The problem formulation uses a general coordinate transformation for arbitrary curvilinear body-fitted computational grids. Some testing using these coordinates is briefly described to help validate the software used for the investigation. The disturbance amplitude ratios as a function of chord position for supersonic (Mach 1.5) boundary layers on untapered, untwisted wings of different sweep angles are then presented and compared with those obtained from local parallel analyses.

  20. Damage Considerations of a Flexible Micro Air Vehicle Wing Using 3-D Laser Vibrometry

    National Research Council Canada - National Science Library

    Mendoza, Jr, Leo L

    2007-01-01

    .... The flexible micro air vehicle wing studied was based on a University of Florida micro air vehicle wing design and was examined using measurements from the Polytec 400-3D Scanning Vibrometer. Comparisons of the wing?s natural frequencies and displacements were made between the wing?s undamaged and damaged states.

  1. Fluctuation conductivity in cuprate superconductors

    Indian Academy of Sciences (India)

    Abstract. We have measured the in-plane resistivity of Bi2Sr2CaCu2O8+δ and Tl2Ba2. CaCu2O8+δ single crystals in the temperature range 70–300 K. The thermodynamic fluctuations in the conductivity of both the samples start around ∼ 125 K. We find the Lawrence and Doniach [1] model to be inadequate to describe the ...

  2. Random numbers from vacuum fluctuations

    International Nuclear Information System (INIS)

    Shi, Yicheng; Kurtsiefer, Christian; Chng, Brenda

    2016-01-01

    We implement a quantum random number generator based on a balanced homodyne measurement of vacuum fluctuations of the electromagnetic field. The digitized signal is directly processed with a fast randomness extraction scheme based on a linear feedback shift register. The random bit stream is continuously read in a computer at a rate of about 480 Mbit/s and passes an extended test suite for random numbers.

  3. Integrated multi-disciplinary design of a sailplane wing

    OpenAIRE

    Strauch, Gregory J.

    1985-01-01

    The objective of this research is to investigate the techniques and payoffs of integrated aircraft design. Lifting line theory and beam theory are used for the analysis of the aerodynamics and the structures of a composite sailplane wing. The wing is described by 33 - 34 design variables which involve the planform geometry, the twist distribution, and thicknesses of the spar caps, spar webs, and the skin at various stations along the wing. The wing design must satisfy 30 â ...

  4. A model for roll stall and the inherent stability modes of low aspect ratio wings at low Reynolds numbers

    Science.gov (United States)

    Shields, Matt

    The development of Micro Aerial Vehicles has been hindered by the poor understanding of the aerodynamic loading and stability and control properties of the low Reynolds number regime in which the inherent low aspect ratio (LAR) wings operate. This thesis experimentally evaluates the static and damping aerodynamic stability derivatives to provide a complete aerodynamic model for canonical flat plate wings of aspect ratios near unity at Reynolds numbers under 1 x 105. This permits the complete functionality of the aerodynamic forces and moments to be expressed and the equations of motion to solved, thereby identifying the inherent stability properties of the wing. This provides a basis for characterizing the stability of full vehicles. The influence of the tip vortices during sideslip perturbations is found to induce a loading condition referred to as roll stall, a significant roll moment created by the spanwise induced velocity asymmetry related to the displacement of the vortex cores relative to the wing. Roll stall is manifested by a linearly increasing roll moment with low to moderate angles of attack and a subsequent stall event similar to a lift polar; this behavior is not experienced by conventional (high aspect ratio) wings. The resulting large magnitude of the roll stability derivative, Cl,beta and lack of roll damping, Cl ,rho, create significant modal responses of the lateral state variables; a linear model used to evaluate these modes is shown to accurately reflect the solution obtained by numerically integrating the nonlinear equations. An unstable Dutch roll mode dominates the behavior of the wing for small perturbations from equilibrium, and in the presence of angle of attack oscillations a previously unconsidered coupled mode, referred to as roll resonance, is seen develop and drive the bank angle? away from equilibrium. Roll resonance requires a linear time variant (LTV) model to capture the behavior of the bank angle, which is attributed to the

  5. Fluctuating hydrodynamics for ionic liquids

    Science.gov (United States)

    Lazaridis, Konstantinos; Wickham, Logan; Voulgarakis, Nikolaos

    2017-04-01

    We present a mean-field fluctuating hydrodynamics (FHD) method for studying the structural and transport properties of ionic liquids in bulk and near electrified surfaces. The free energy of the system consists of two competing terms: (1) a Landau-Lifshitz functional that models the spontaneous separation of the ionic groups, and (2) the standard mean-field electrostatic interaction between the ions in the liquid. The numerical approach used to solve the resulting FHD-Poisson equations is very efficient and models thermal fluctuations with remarkable accuracy. Such density fluctuations are sufficiently strong to excite the experimentally observed spontaneous formation of liquid nano-domains. Statistical analysis of our simulations provides quantitative information about the properties of ionic liquids, such as the mixing quality, stability, and the size of the nano-domains. Our model, thus, can be adequately parameterized by directly comparing our prediction with experimental measurements and all-atom simulations. Conclusively, this work can serve as a practical mathematical tool for testing various theories and designing more efficient mixtures of ionic liquids.

  6. Heat fluctuations and initial ensembles

    Science.gov (United States)

    Kim, Kwangmoo; Kwon, Chulan; Park, Hyunggyu

    2014-09-01

    Time-integrated quantities such as work and heat increase incessantly in time during nonequilibrium processes near steady states. In the long-time limit, the average values of work and heat become asymptotically equivalent to each other, since they only differ by a finite energy change in average. However, the fluctuation theorem (FT) for the heat is found not to hold with the equilibrium initial ensemble, while the FT for the work holds. This reveals an intriguing effect of everlasting initial memory stored in rare events. We revisit the problem of a Brownian particle in a harmonic potential dragged with a constant velocity, which is in contact with a thermal reservoir. The heat and work fluctuations are investigated with initial Boltzmann ensembles at temperatures generally different from the reservoir temperature. We find that, in the infinite-time limit, the FT for the work is fully recovered for arbitrary initial temperatures, while the heat fluctuations significantly deviate from the FT characteristics except for the infinite initial-temperature limit (a uniform initial ensemble). Furthermore, we succeed in calculating finite-time corrections to the heat and work distributions analytically, using the modified saddle point integral method recently developed by us. Interestingly, we find noncommutativity between the infinite-time limit and the infinite-initial-temperature limit for the probability distribution function (PDF) of the heat.

  7. Primordial fluctuations without scalar fields

    Science.gov (United States)

    Magueijo, João; Noller, Johannes

    2010-02-01

    We revisit the question of whether fluctuations in hydrodynamical, adiabatical matter could explain the observed structures in our Universe. We consider matter with variable equation of state w=p0/ɛ0 and a concomitant (under the adiabatic assumption) density dependent speed of sound, cs. We find a limited range of possibilities for a setup when modes start inside the Hubble radius, then leaving it and freezing out. For expanding universes, power-law w(ɛ0) models are ruled out (except when cs2∝w≪1, requiring post-stretching the seeded fluctuations); but sharper profiles in cs do solve the horizon problem. Among these, a phase transition in cs is notable for leading to scale-invariant fluctuations if the initial conditions are thermal. For contracting universes all power-law w(ɛ0) solve the horizon problem, but only one leads to scale-invariance: w∝ɛ02 and cs∝ɛ0. This model bypasses a number of problems with single scalar field cyclic models (for which w is large but constant).

  8. Mathematical modeling of planar cell polarity signaling in the Drosophila melanogaster wing

    Science.gov (United States)

    Amonlirdviman, Keith

    Planar cell polarity (PCP) signaling refers to the coordinated polarization of cells within the plane of various epithelial tissues to generate sub-cellular asymmetry along an axis orthogonal to their apical-basal axes. For example, in the Drosophila wing, PCP is seen in the parallel orientation of hairs that protrude from each of the approximately 30,000 epithelial cells to robustly point toward the wing tip. Through a poorly understood mechanism, cell clones mutant for some PCP signaling components, including some, but not all alleles of the receptor frizzled, cause polarity disruptions of neighboring, wild-type cells, a phenomenon referred to as domineering nonautonomy. Previous models have proposed diffusible factors to explain nonautonomy, but no such factors have yet been found. This dissertation describes the mathematical modeling of PCP in the Drosophila wing, based on a contact dependent signaling hypothesis derived from experimental results. Intuition alone is insufficient to deduce that this hypothesis, which relies on a local feedback loop acting at the cell membrane, underlies the complex patterns observed in large fields of cells containing mutant clones, and others have argued that it cannot account for observed phenotypes. Through reaction-diffusion, partial differential equation modeling and simulation, the feedback loop is shown to fully reproduce PCP phenotypes, including domineering nonautonomy. The sufficiency of this model and the experimental validation of model predictions argue that previously proposed diffusible factors need not be invoked to explain PCP signaling and reveal how specific protein-protein interactions lead to autonomy or domineering nonautonomy. Based on these results, an ordinary differential equation model is derived to study the relationship of the feedback loop with upstream signaling components. The cadherin Fat transduces a cue to the local feedback loop, biasing the polarity direction of each cell toward the wing tip

  9. Asymmetries of Knowledge and Epistemic Change in Social Gaming Interaction

    Science.gov (United States)

    Piirainen-Marsh, Arja; Tainio, Liisa

    2014-01-01

    While a growing number of studies investigate the role of knowledge and interactional management of knowledge asymmetries in conversation analysis, the epistemic organization of multilingual and second language interactions is still largely unexplored. This article addresses this issue by investigating how knowledge asymmetries and changing…

  10. CP violating rate asymmetries in B decays ∑

    Indian Academy of Sciences (India)

    CP violating rate asymmetries in B decays. N G DESHPANDE. Institute of Theoretical Science, University of Oregon, Eugene, Oregon 97403-5203, USA. Email: desh@oregon.uoregon.edu. Abstract. We briefly discuss measurements of angles β and α of the unitarity triangle. We then review rate asymmetries using SU´3µ ...

  11. Disentangling the Relationship between Hemispheric Asymmetry and Cognitive Performance

    Science.gov (United States)

    Hirnstein, Marco; Leask, Stuart; Rose, Jonas; Hausmann, Markus

    2010-01-01

    It is widely believed that advantages of hemispheric asymmetries originated in better cognitive processing, hence it is often implied that the relationship between hemispheric asymmetry and cognitive performance is linearly positive: the higher the degree of lateralization in a specific cognitive domain, the better the performance in a…

  12. Identification of Foot Pathologies Based on Plantar Pressure Asymmetry

    Directory of Open Access Journals (Sweden)

    Linah Wafai

    2015-08-01

    Full Text Available Foot pathologies can negatively influence foot function, consequently impairing gait during daily activity, and severely impacting an individual’s quality of life. These pathologies are often painful and correspond with high or abnormal plantar pressure, which can result in asymmetry in the pressure distribution between the two feet. There is currently no general consensus on the presence of asymmetry in able-bodied gait, and plantar pressure analysis during gait is in dire need of a standardized method to quantify asymmetry. This paper investigates the use of plantar pressure asymmetry for pathological gait diagnosis. The results of this study involving plantar pressure analysis in fifty one participants (31 healthy and 20 with foot pathologies support the presence of plantar pressure asymmetry in normal gait. A higher level of asymmetry was detected at the majority of the regions in the feet of the pathological population, including statistically significant differences in the plantar pressure asymmetry in two regions of the foot, metatarsophalangeal joint 3 (MPJ3 and the lateral heel. Quantification of plantar pressure asymmetry may prove to be useful for the identification and diagnosis of various foot pathologies.

  13. Spatial asymmetry of post-stroke hemiparetic gait: assessment and ...

    African Journals Online (AJOL)

    Despite potential benefits, quantitative analysis of gait asymmetry is still not routinely used in many hospitals and rehabilitation institutions in developing countries due to ... Conclusion: Overall, the study demonstrated asymmetry of step length and foot rotation angle during walking of post-stroke hemiparetic individuals and ...

  14. Information Asymmetries as Trade Barriers: ISO 9000 Increases International Commerce

    Science.gov (United States)

    Potoski, Matthew; Prakash, Aseem

    2009-01-01

    Spatial, cultural, and linguistic barriers create information asymmetries between buyers and sellers that impede international trade. The International Organization for Standardization's ISO 9000 program is designed to reduce these information asymmetries by providing assurance about the product quality of firms that receive its certification.…

  15. Use of wing morphometry for the discrimination of some Cerceris ...

    African Journals Online (AJOL)

    use

    2011-12-14

    Dec 14, 2011 ... Figure 12. Thin spline plate graphics for the species belonging to the genus Cerceris. Figure 13. Fore wing landmarks of the significant wing characteristics in the honeybee Apis mellifera. Linnaeus. stated as the traditional wing morphometry that enables the practical discrimination of the honeybee (Apis sp ...

  16. How swifts control their glide performance with morphing wings

    NARCIS (Netherlands)

    Lentink, D.; Muller, U. K.; Stamhuis, E. J.; de Kat, R.; van Gestel, W.; Veldhuis, L. L. M.; Henningsson, P.; Hedenstrom, A.; Videler, J. J.

    2007-01-01

    Gliding birds continually change the shape and size of their wings(1-6), presumably to exploit the profound effect of wing morphology on aerodynamic performance(7-9). That birds should adjust wing sweep to suit glide speed has been predicted qualitatively by analytical glide models(2,10), which

  17. Study of design parameters of flapping-wings

    NARCIS (Netherlands)

    Wang, Q.; Goosen, J.F.L.; Van Keulen, F.

    2014-01-01

    As one of the most important components of a flapping-wing micro air vehicle (FWMAV), the design of an energy-efficient flapping-wing has been a research interest recently. Research on insect flight from different perspectives has been carried out, mainly with regard to wing morphology, flapping

  18. Low Reynolds Number Wing Transients in Rotation and Translation

    Science.gov (United States)

    Jones, Anya; Schlueter, Kristy

    2012-11-01

    The unsteady aerodynamic forces and flow fields generated by a wing undergoing transient motions in both rotation and translation were investigated. An aspect ratio 2 flat plate wing at a 45 deg angle of attack was driven over 84 deg of rotation (3 chord-lengths of travel at 3/4 span) and 3 and 10 chord-lengths of translation in quiescent water at Reynolds numbers between 2,500 and 15,000. Flow visualization on the rotating wing revealed a leading edge vortex that lifted off of the wing surface, but remained in the vicinity of the wing for the duration of the wing stroke. A second spanwise vortex with strong axial flow was also observed. As the tip vortex grew, the leading edge vortex joined the tip vortex in a loop-like structure over the aft half of the wing. Near the leading edge, spanwise flow in the second vortex became entrained in the tip vortex near the corner of the wing. Unsteady force measurements revealed that lift coefficient increased through the constant-velocity portion of the wing stroke. Forces were compared for variations in wing acceleration and Reynolds number for both rotational and translational motions. The effect of tank blockage was investigated by repeating the experiments on multiple wings, varying the distance between the wing tip and tank wall. U.S. Air Force Research Laboratory, Summer Faculty Fellowship Program.

  19. Numerical investigation of unsteady vortex breakdown past 80°/65° double-delta wing

    Directory of Open Access Journals (Sweden)

    Liu Jian

    2014-06-01

    Full Text Available An improved delayed detached eddy simulation (IDDES method based on the k-ω-SST (shear stress transport turbulence model was applied to predict the unsteady vortex breakdown past an 80°/65° double-delta wing (DDW, where the angles of attack (AOAs range from 30° to 40°. Firstly, the IDDES model and the relative numerical methods were validated by simulating the massively separated flow around an NACA0021 straight wing at the AOA of 60°. The fluctuation properties of the lift and pressure coefficients were analyzed and compared with the available measurements. For the DDW case, the computations were compared with such measurements as the mean lift, drag, pitching moment, pressure coefficients and breakdown locations. Furthermore, the unsteady properties were investigated in detail, such as the frequencies of force and moments, pressure fluctuation on the upper surface, typical vortex breakdown patterns at three moments, and the distributions of kinetic turbulence energy at a stream wise section. Two dominated modes are observed, in which their Strouhal numbers are 1.0 at the AOAs of 30°, 32° and 34° and 0.7 at the AOAs of 36°, 38° and 40°. The breakdown vortex always moves upstream and downstream and its types change alternatively. Furthermore, the vortex can be identified as breakdown or not through the mean pressure, root mean square of pressure, or even through correlation analysis.

  20. Contract Design: The problem of information asymmetry

    Directory of Open Access Journals (Sweden)

    Axel C. Mühlbacher

    2018-01-01

    Full Text Available Introduction: Integrated care systems are advocated as an effective method of improving the performance of healthcare systems. These systems outline a payment and care delivery model that intends to tie provider reimbursements to predefined quality metrics. Little is known about the contractual design and the main challenges of delegating “accountability” to these new kinds of organisations and/or contracts. The research question in this article focuses on how healthcare contracts can look like and which possible problems arise in designing such contracts. In this a special interest is placed on information asymmetries.  Methods: A comprehensive literature review on methods of designing contracts in Integrated Care was conducted. This article is the first in a row of three that all contribute to a specific issue in designing healthcare contracts. Starting with the organisation of contracts and information asymmetries, part 2 focusses on financial options and risks and part 3 finally concludes with the question of risk management and evaluation.  Results: Healthcare contracting between providers and payers will have a major impact on the overall design of future healthcare systems. If Integrated care systems or any other similar concept of care delivery are to be contracted directly by payers to manage the continuum of care the costs of market utilisation play an essential role. Transaction costs also arise in the course of the negotiation and implementation of contracts. These costs are the reason why it is generally not possible to conclude perfect (complete contracts. Problems with asymmetric distribution of information can relate to the situation before a contract is concluded (adverse selection and after conclusion of a contract (moral hazard.  Discussion and Conclusions: Information asymmetries are seen as a major obstacle to the efficient operation of integrated care programmes. Coordination and motivation problems cannot be solved

  1. Measurement of magnetic fluctuation induced energy transport

    International Nuclear Information System (INIS)

    Fiksel, G.; Prager, S.C.; Shen, W.; Stoneking, M.

    1993-11-01

    The local electron energy flux produced by magnetic fluctuations has been measured directly in the MST reversed field pinch (over the radial range r/a > 0.75). The flux, produced by electrons traveling parallel to a fluctuating magnetic field, is obtained from correlation between the fluctuations in the parallel heat flux and the radial magnetic field. The fluctuation induced flux is large (100 kW/cm 2 ) in the ''core'' (r/a 2 ) in the edge

  2. A Point-Wise Quantification of Asymmetry Using Deformation Fields

    DEFF Research Database (Denmark)

    Ólafsdóttir, Hildur; Lanche, Stephanie; Darvann, Tron Andre

    2007-01-01

    of the resulting displacement vectors on the left and right side of the symmetry plane, gives a point-wise measure of asymmetry. The asymmetry measure was applied to the study of Crouzon syndrome using Micro CT scans of genetically modified mice. Crouzon syndrome is characterised by the premature fusion of cranial...... sutures, which gives rise to a highly asymmetric growth. Quantification and localisation of this asymmetry is of high value with respect to surgery planning and treatment evaluation. Using the proposed method, asymmetry was calculated in each point of the surface of Crouzon mice and wild-type mice...... (controls). Asymmetry appeared in similar regions for the two groups but the Crouzon mice were found significantly more asymmetric. The localisation ability of the method was in good agreement with ratings from a clinical expert. Validating the quantification ability is a less trivial task due to the lack...

  3. Air Base Wing and Air Mobility Wing Consolidating on AMC-LED Joint Bases: A Delphi Study

    Science.gov (United States)

    2014-06-13

    AIR BASE WING AND AIR MOBILITY WING CONSOLIDATION ON AMC-LED JOINT BASES: A DELPHI STUDY GRADUATE RESEARCH PAPER Mason E. MacGarvey... DELPHI STUDY GRADUATE RESEARCH PAPER Presented to the Faculty Graduate School of Engineering Management Air Force Institute of Technology...iv AIR BASE WING AND AIR MOBILITY WING CONSOLIDATION ON AMC-LED JOINT BASES: A DELPHI STUDY Mason E. MacGarvey, BS, MBA

  4. Wall pressure fluctuations in rod bundles

    International Nuclear Information System (INIS)

    Moeller, S.V.

    1990-01-01

    Microphones and hot wires were applied for the measurement of wall pressure fluctuations and velocity fluctuations in rod bundles with several aspect ratios. By means of auto and cross spectral density functions their interdependence was investigated. Results show that the pressure fluctuations in rod bundles are mainly associated with the phenomenon of quasi-periodic flow pulsations between subchannels. (author)

  5. Machine Learning for Flapping Wing Flight Control

    NARCIS (Netherlands)

    Goedhart, Menno; van Kampen, E.; Armanini, S.F.; de Visser, C.C.; Chu, Q.

    2018-01-01

    Flight control of Flapping Wing Micro Air Vehicles is challenging, because of their complex dynamics and variability due to manufacturing inconsistencies. Machine Learning algorithms can be used to tackle these challenges. A Policy Gradient algorithm is used to tune the gains of a

  6. Migration on Wings Aerodynamics and Energetics

    CERN Document Server

    Kantha, Lakshmi

    2012-01-01

    This book is an effort to explore the technical aspects associated with bird flight and migration on wings. After a short introduction on the birds migration, the book reviews the aerodynamics and Energetics of Flight and presents the calculation of the Migration Range. In addition, the authors explains aerodynamics of the formation flight and finally introduces great flight diagrams.

  7. Oblique-Flying-Wing Supersonic Transport Airplane

    Science.gov (United States)

    Van Der Velden, Alexander J. M.

    1992-01-01

    Oblique-flying-wing supersonic airplane proposed as possible alternative to B747B (or equivalent). Tranports passengers and cargo as fast as twice speed of sound at same cost as current subsonic transports. Flies at same holding speeds as present supersonic transports but requires only half takeoff distance.

  8. Chemical evaluation of winged beans ( Psophocarpus ...

    African Journals Online (AJOL)

    Chemical evaluation of winged beans ( Psophocarpus Tetragonolobus ), Pitanga cherries ( Eugenia uniflora) and orchid fruit ( Orchid fruit myristic a) ... The acid value ranged between 0.71 and 2.82 mg/KOH/g while iodine value ranged between 91.15 and 144.57. The refractive index ranged between 1.465 and 1.474 in all ...

  9. ``Schooling'' of wing pairs in flapping flight

    Science.gov (United States)

    Ramananarivo, Sophie; Zhang, Jun; Ristroph, Leif; AML, Courant Collaboration; Physics NYU Collaboration

    2015-11-01

    The experimental setup implements two independent flapping wings swimming in tandem. Both are driven with the same prescribed vertical heaving motion, but the horizontal motion is free, which means that the swimmers can take up any relative position and forward speed. Experiments show however clearly coordinated motions, where the pair of wings `crystallize' into specific stable arrangements. The follower wing locks into the path of the leader, adopting its speed, and with a separation distance that takes on one of several discrete values. By systematically varying the kinematics and wing size, we show that the set of stable spacings is dictated by the wavelength of the periodic wake structure. The forces maintaining the pair cohesion are characterized by applying an external force to the follower to perturb it away from the `stable wells'. These results show that hydrodynamics alone is sufficient to induce cohesive and coordinated collective locomotion through a fluid, and we discuss the hypothesis that fish schools and bird flocks also represent stable modes of motion.

  10. A Combinatorial Approach to Time Asymmetry

    Directory of Open Access Journals (Sweden)

    Martin Tamm

    2016-03-01

    Full Text Available In this paper, simple models for the multiverse are analyzed. Each universe is viewed as a path in a graph, and by considering very general statistical assumptions, essentially originating from Boltzmann, we can make the set of all such paths into a finite probability space. We can then also attempt to compute the probabilities for different kinds of behavior and in particular under certain conditions argue that an asymmetric behavior of the entropy should be much more probable than a symmetric one. This offers an explanation for the asymmetry of time as a broken symmetry in the multiverse. The focus here is on simple models which can be analyzed using methods from combinatorics. Although the computational difficulties rapidly become enormous when the size of the model grows, this still gives hints about how a full-scale model should behave.

  11. Intraday market asymmetries — A Nordic example

    DEFF Research Database (Denmark)

    Soysal, Emilie Rosenlund; Olsen, Ole Jess; Skytte, Klaus

    2017-01-01

    , particularly important for VRE producers, but it also means that the price formation at intraday market can change optimal bidding strategy in the day-ahead market. Through econometric modelling of intraday price premiums, this paper investigates intraday price asymmetries, which potentially can lead...... to strategic bidding. The intraday market is per definition symmetric, as prices for power sales always correspond to prices for power purchases, however, we find that this symmetry is not reflected in the price structure in regards to the total load adjustment needs.......While the majority of electricity in the Nordic and Baltic countries is traded at the day-ahead market, producers and consumers can use the intraday market to adjust their production commitments according to updated forecasts closer to the time of delivery. This reduces the need for balancing...

  12. Cultural Distance Asymmetry in Expatriate Adjustment

    DEFF Research Database (Denmark)

    Selmer, Jan; Chiu, Randy K.; Shenkar, Oded

    2007-01-01

    Purpose - The current literature implicitly assumes a symmetric impact of cultural distance (CD) on expatriate adjustment. By using distance as a predictor of adjustment, the literature has rendered the direction of the flow irrelevant: a US expatriate in Germany is presumed to face the same hurdle...... of the assignment. Design/methodology/approach - Using a two-flow sample of US expatriates in Germany and German expatriates in the USA, we examine and compare the psychological and socio-cultural adjustment of each group of executives. Findings - Controlling for the length of assignment, we find that German...... expatriates in the USA were better adjusted, both socio-culturally and psychologically, than American expatriates in Germany. These results support the asymmetry hypothesis and call into question previous findings attesting to the relationship between CD and expatriate adjustment. Originality...

  13. Subsurface Nonlinear Dynamical Heating and ENSO Asymmetry

    Science.gov (United States)

    Hayashi, Michiya; Jin, Fei-Fei

    2017-12-01

    This study presents evidence of interannual to interdecadal variabilities residing in the subsurface nonlinear dynamical heating (NDH) along the equatorial Pacific thermocline based on ocean reanalysis products. In association with a flattened thermocline and drastic halt of the Equatorial Undercurrent, the NDH increases sharply right after a peak of the strong El Niño, reducing the linear anomalous advective subsurface cooling by 30%. As the result, subsurface cold signals in the west are significantly weakened as it reaches the easternmost Pacific, causing less surface cooling in the east and thus weakening the subsequent La Niña. Therefore, the subsurface NDH contributes to asymmetry in both the magnitude and structure between El Niño and La Niña. The acute positive subsurface NDH associated with strong El Niño events leads to substantial variations in its decadal means and serves as a potential source for tropical Pacific decadal to interdecadal variabilities.

  14. Symmetry and asymmetry in mandelate racemase catalysis

    International Nuclear Information System (INIS)

    Whitman, C.P.; Hegeman, G.D.; Cleland, W.W.; Kenyon, G.L.

    1985-01-01

    Kinetic properties of mandelate racemase catalysis (Vmax, Km, deuterium isotope effects, and pH profiles) were all measured in both directions by the circular dichroic assay of Sharp. These results, along with those of studying interactions of mandelate racemase with resolved, enantiomeric competitive inhibitors [(R)- and (S)-alpha-phenylglycerates], indicate a high degree of symmetry in both binding and catalysis. Racemization of either enantiomer of mandelate in D 2 O did not show an overshoot region of molecular ellipticity in circular dichroic measurements upon approach to equilibrium. Both the absence of such an overshoot region and the high degree of kinetic symmetry are consistent with a one-base acceptor mechanism for mandelate racemase. On the other hand, results of irreversible inhibition with partially resolved, enantiomeric affinity labels [(R)- and (S)-alpha-phenylglycidates] reveal a ''functional asymmetry'' at the active site. Mechanistic proposals, consistent with these results, are presented

  15. Aerodynamic comparison of a butterfly-like flapping wing-body model and a revolving-wing model

    Science.gov (United States)

    Suzuki, Kosuke; Yoshino, Masato

    2017-06-01

    The aerodynamic performance of flapping- and revolving-wing models is investigated by numerical simulations based on an immersed boundary-lattice Boltzmann method. As wing models, we use (i) a butterfly-like model with a body and flapping-rectangular wings and (ii) a revolving-wing model with the same wings as the flapping case. Firstly, we calculate aerodynamic performance factors such as the lift force, the power, and the power loading of the two models for Reynolds numbers in the range of 50-1000. For the flapping-wing model, the power loading is maximal for the maximum angle of attack of 90°, a flapping amplitude of roughly 45°, and a phase shift between the flapping angle and the angle of attack of roughly 90°. For the revolving-wing model, the power loading peaks for an angle of attack of roughly 45°. In addition, we examine the ground effect on the aerodynamic performance of the revolving-wing model. Secondly, we compare the aerodynamic performance of the flapping- and revolving-wing models at their respective maximal power loadings. It is found that the revolving-wing model is more efficient than the flapping-wing model both when the body of the latter is fixed and where it can move freely. Finally, we discuss the relative agilities of the flapping- and revolving-wing models.

  16. Paleozoic Nymphal Wing Pads Support Dual Model of Insect Wing Origins.

    Science.gov (United States)

    Prokop, Jakub; Pecharová, Martina; Nel, André; Hörnschemeyer, Thomas; Krzemińska, Ewa; Krzemiński, Wiesław; Engel, Michael S

    2017-01-23

    The appearance of wings in insects, early in their evolution [1], has been one of the more critical innovations contributing to their extraordinary diversity. Despite the conspicuousness and importance of wings, the origin of these structures has been difficult to resolve and represented one of the "abominable mysteries" in evolutionary biology [2]. More than a century of debate has boiled the matter down to two competing alternatives-one of wings representing an extension of the thoracic notum, the other stating that they are appendicular derivations from the lateral body wall. Recently, a dual model has been supported by genomic and developmental data [3-6], representing an amalgamation of elements from both the notal and pleural hypotheses. Here, we reveal crucial information from the wing pad joints of Carboniferous palaeodictyopteran insect nymphs using classical and high-tech techniques. These nymphs had three pairs of wing pads that were medially articulated to the thorax but also broadly contiguous with the notum anteriorly and posteriorly (details unobservable in modern insects), supporting their overall origin from the thoracic notum as well as the expected medial, pleural series of axillary sclerites. Our study provides support for the formation of the insect wing from the thoracic notum as well as the already known pleural elements of the arthropodan leg. These results support the unique, dual model for insect wing origins and the convergent reduction of notal fusion in more derived clades, presumably due to wing rotation during development, and they help to bring resolution to this long-standing debate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Exploring the relationship between hypoplasia and odontometric asymmetry in Isola Sacra, an imperial Roman necropolis.

    Science.gov (United States)

    Hoover, Kara C; Corruccini, Robert S; Bondioli, Luca; Macchiarelli, Roberto

    2005-01-01

    Anthropological studies reporting odontometric asymmetry values or dental enamel hypoplasia frequencies use these markers as a record of physiological perturbations occurring during dental development. While both markers indirectly suggest the amount of relative stress a population might have experienced, a relationship between the two has been explored only recently in the literature. In this study, we address the possibility of such a relationship in two ways. First, Kendall's tau B correlations test the degree of relationship on the level of the individual between hypoplasia presence/absence (P/A) and severity of hypoplasia appearance (PS) data for the anterior dentition and directional (DA) and fluctuating asymmetry (FA) data for concurrently developing molars pairs. Second, an F-test explores between-group (ranked hypoplastic individuals and non-hypoplastic individuals) variance about the mean, expecting the hypoplastic individuals to be more variable. The sample consists of 72 individuals from the Isola Sacra necropolis, which is associated with Portus, the port city of ancient Rome. Results indicated only a very weak predictive relationship between some variables and few significant differences in variation. However, variance follows trends in published literature. Possible explanations for the lack of interaction on the level of the individual include both etiological and genetic susceptibility factors that are significant in and of themselves as they suggest a more complex reading of the hard tissue evidence for stress in archaeological populations. Copyright 2005 Wiley-Liss, Inc

  18. Skull shape asymmetry and the socioeconomic structure of an early medieval central European society.

    Science.gov (United States)

    Bigoni, Lucie; Krajíček, Václav; Sládek, Vladimír; Velemínský, Petr; Velemínská, Jana

    2013-03-01

    The socioeconomic structure of an early medieval society from the Mikulčice settlement (Czech Republic) was studied on the basis of an evaluation of the fluctuating and directional asymmetry (DA) of skulls. Two distinct inhabited regions, castle and sub-castle, were compared. Fluctuating asymmetry (FA) was used as a bioindicator of environmental stress, which is thought to have been different in the Mikulčice castle and sub-castle regions. DA is consistent with biomechanical loading, and it was expected to reflect different subsistence patterns. The material consisted of 129 crania from what was presumed to be a higher socioeconomic class (Mikulčice castle) and 71 crania from middle and lower socioeconomic classes (Mikulčice sub-castle). As a comparative sample, 138 crania from modern, lower socioeconomic classes (Pachner Collection) were used. The three-dimensional coordinates of 68 landmarks were digitized and analyzed using geometric morphometrics. In terms of DA, the highest values were recorded in the sub-castle sample and confirmed their lower socioeconomic position, with a grittier and lower protein diet compared with the castle sample. In terms of FA, distinctive differences between the sexes were found. In males, no differences were observed between castle and sub-castle, and the lowest FA values were recorded. In females, significantly higher values of FA were found, surprisingly in the castle sample, comparable with the more stressed Pachner Collection. We suspect that the FA reflects a more varied population of castle females as a consequence of patrilocality, although environmental stress remains a possibility. Copyright © 2013 Wiley Periodicals, Inc.

  19. Interplay of Dirac surface states and magnetic fluctuations in topological insulator heterostructures

    Science.gov (United States)

    Hurst, Hilary M.; Efimkin, Dmitry K.; Galitski, Victor

    We consider the proximity effect between Dirac states at the surface of a topological insulator and a ferromagnet with easy plane anisotropy, which is described by the XY-model and undergoes a Berezinskii-Kosterlitz-Thouless (BKT) phase transition. Classical magnetic fluctuations interacting with the surface states of a topological insulator can be described by an effective gauge field. This model can be mapped onto the problem of Dirac fermions in a random magnetic field, however this analogy is only partial in the presence of electron-hole asymmetry or warping of the Dirac dispersion which results in screening of magnetic fluctuations. We show that this proximity coupling leads to anomalous transport behavior of the surface states near the BKT transition temperature.

  20. Critical swelling of fluctuating capsules

    Science.gov (United States)

    Diamant, Haim; Haleva, Emir

    2009-03-01

    In many natural transport processes the solute molecules to be transported are encapsulated in semipermeable, flexible membrane vesicles of micron size. We study the swelling of such fluctuating capsules, as the number of encapsulated particles is increased, or the concentration of the outer solution is decreased. The approach to the maximum volume-to-area ratio and the associated buildup of membrane tension involve a continuous phase transition and follow universal scaling laws. The criticality and its features are model-independent, arising solely from the interplay between volume and surface degrees of freedom.ootnotetextE. Haleva and H. Diamant, Phys. Rev. Lett. 101, 078104 (2008).

  1. Noise and fluctuations an introduction

    CERN Document Server

    MacDonald, D K C

    2006-01-01

    An understanding of fluctuations and their role is both useful and fundamental to the study of physics. This concise study of random processes offers graduate students and research physicists a survey that encompasses both the relationship of Brownian Movement with statistical mechanics and the problem of irreversible processes. It outlines the basics of the physics involved, without the strictures of mathematical rigor.The three-part treatment starts with a general survey of Brownian Movement, including electrical Brownian Movement and ""shot-noise,"" Part two explores correlation, frequency

  2. Fluctuations in Overlapping Generations Economies

    DEFF Research Database (Denmark)

    Tvede, Mich

    In the present paper stationary pure-exchange overlapping generations economies with l  goods per date and m consumers per generation are considered. It is shown that for an open and dense set of utility functions there exist endowment vectors such that n-cycles exist for n = l +1 and l  = m....... The approach to existence of endogenous fluctuations is basic in the sense that the prime ingredients are the implicit function theorem and linear algebra. Moreover the approach is applied to show that for an open and dense set of utility functions there exist endowment vectors such that sunspot equilibria...

  3. Multiple cues for winged morph production in an aphid metacommunity.

    Directory of Open Access Journals (Sweden)

    Mohsen Mehrparvar

    Full Text Available Environmental factors can lead individuals down different developmental pathways giving rise to distinct phenotypes (phenotypic plasticity. The production of winged or unwinged morphs in aphids is an example of two alternative developmental pathways. Dispersal is paramount in aphids that often have a metapopulation structure, where local subpopulations frequently go extinct, such as the specialized aphids on tansy (Tanacetum vulgare. We conducted various experiments to further understand the cues involved in the production of winged dispersal morphs by the two dominant species of the tansy aphid metacommunity, Metopeurum fuscoviride and Macrosiphoniella tanacetaria. We found that the ant-tended M. fuscoviride produced winged individuals predominantly at the beginning of the season while the untended M. tanacetaria produced winged individuals throughout the season. Winged mothers of both species produced winged offspring, although in both species winged offspring were mainly produced by unwinged females. Crowding and the presence of predators, effects already known to influence wing production in other aphid species, increased the percentage of winged offspring in M. tanacetaria, but not in M. fuscoviride. We find there are also other factors (i.e. temporal effects inducing the production of winged offspring for natural aphid populations. Our results show that the responses of each aphid species are due to multiple wing induction cues.

  4. The biomechanical origin of extreme wing allometry in hummingbirds.

    Science.gov (United States)

    Skandalis, Dimitri A; Segre, Paolo S; Bahlman, Joseph W; Groom, Derrick J E; Welch, Kenneth C; Witt, Christopher C; McGuire, Jimmy A; Dudley, Robert; Lentink, David; Altshuler, Douglas L

    2017-10-19

    Flying animals of different masses vary widely in body proportions, but the functional implications of this variation are often unclear. We address this ambiguity by developing an integrative allometric approach, which we apply here to hummingbirds to examine how the physical environment, wing morphology and stroke kinematics have contributed to the evolution of their highly specialised flight. Surprisingly, hummingbirds maintain constant wing velocity despite an order of magnitude variation in body weight; increased weight is supported solely through disproportionate increases in wing area. Conversely, wing velocity increases with body weight within species, compensating for lower relative wing area in larger individuals. By comparing inter- and intraspecific allometries, we find that the extreme wing area allometry of hummingbirds is likely an adaptation to maintain constant burst flight capacity and induced power requirements with increasing weight. Selection for relatively large wings simultaneously maximises aerial performance and minimises flight costs, which are essential elements of humming bird life history.

  5. An Objective Fluctuation Score for Parkinson's Disease

    Science.gov (United States)

    Horne, Malcolm K.; McGregor, Sarah; Bergquist, Filip

    2015-01-01

    Introduction Establishing the presence and severity of fluctuations is important in managing Parkinson’s Disease yet there is no reliable, objective means of doing this. In this study we have evaluated a Fluctuation Score derived from variations in dyskinesia and bradykinesia scores produced by an accelerometry based system. Methods The Fluctuation Score was produced by summing the interquartile range of bradykinesia scores and dyskinesia scores produced every 2 minutes between 0900-1800 for at least 6 days by the accelerometry based system and expressing it as an algorithm. Results This Score could distinguish between fluctuating and non-fluctuating patients with high sensitivity and selectivity and was significant lower following activation of deep brain stimulators. The scores following deep brain stimulation lay in a band just above the score separating fluctuators from non-fluctuators, suggesting a range representing adequate motor control. When compared with control subjects the score of newly diagnosed patients show a loss of fluctuation with onset of PD. The score was calculated in subjects whose duration of disease was known and this showed that newly diagnosed patients soon develop higher scores which either fall under or within the range representing adequate motor control or instead go on to develop more severe fluctuations. Conclusion The Fluctuation Score described here promises to be a useful tool for identifying patients whose fluctuations are progressing and may require therapeutic changes. It also shows promise as a useful research tool. Further studies are required to more accurately identify therapeutic targets and ranges. PMID:25928634

  6. Kinetic asymmetries between forward and drop jump landing tasks

    Directory of Open Access Journals (Sweden)

    Morgana Alves de Britto

    2015-12-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2015v17n6p661   Landing asymmetry is a risk factor for knee anterior cruciate ligament injury. The aim of this study was to identify kinetic asymmetries in healthy recreational athletes performing different jump-landing techniques. Twelve recreational athletes engaged in regular training underwent kinetic evaluation using two 3D force plates and were analyzed for: (a three-dimensional peak forces, (b time to peak vertical force, and (c initial phase asymmetries. All data were collected during performance of unilateral and bilateral trials of forward and drop jump tasks. Forward jump-landing tasks elicited greater kinetic asymmetry than drop-landing tasks. Regardless of jump-landing technique, the preferred leg experienced higher forces than the non-preferred leg. The initial landing phase showed more kinetic asymmetries than the later phase when peak vertical forces occur. It was concluded that when screening athletes for kinetic asymmetries that may predispose them to injury, forward jump-landing tasks and the early landing phase might show more kinetic asymmetries than drop jump-landing tasks and the late landing phase, respectively.

  7. Bilateral asymmetry of the humerus during growth and development.

    Science.gov (United States)

    Blackburn, Amanda

    2011-08-01

    The development of handedness throughout growth can be investigated by using bilateral asymmetry of the humerus as a proxy for this trait. A large skeletal sample of nonadults from English archaeological sites was examined using standard metric techniques to assess when right-sided asymmetry first appears in the human skeleton. Results of this work indicate a change in directional asymmetry during growth and development, with infants and young children exhibiting no significant asymmetry and older children and adolescents demonstrating right-sidedness. This trend is consistent with what has been observed in previous studies of upper limb asymmetry in skeletal material and behaviorally in living children, adding further strength to the premise that biomechanical forces strongly influence bilateral asymmetry in the upper limb bones. Variability in the magnitude of asymmetry between different features of the humerus was also noted. This characteristic can be explained by differing degrees of genetic canalization, with length and articular dimensions being more strongly canalized than diaphyseal properties. Copyright © 2011 Wiley-Liss, Inc.

  8. Measurement of ttbar forward-backward asymmetry at CDF

    CERN Multimedia

    CERN. Geneva

    2011-01-01

    Early measurements of the forward-backward ttbar production asymmetry at CDF and D0 suggested significant asymmetries that have been interpreted as evidence for exotic gluon partners or new t-channel interactions. We present new measurements performed with 5 fb-1 of Tevatron ppbar collisions at Ecm = 1.96 TeV, recorded and analyzed at CDF. Significant inclusive asymmetries are observed in both the lepton+jets and the dilepton decay modes of the ttbar pair. In the dilepton mode, the asymmetry is observed in the reconstructed top rapidity, and in the lepton rapidity difference, which is independent of any top reconstruction. In the lepton plus jets sample, the full reconstruction of the top kinematics is used to measure the dependence of the asymmetry on the tt bar rapidity difference Delta(y) and the invariant mass M_(ttbar ) of the ttbar system. The asymmetry is found to be most significant at large Delta(y) and M_(ttbar) . For M_(ttbar) > 450 GeV/c2, the parton-level asymmetry in the t-tbar rest frame is...

  9. Magnetic fields and chiral asymmetry in the early hot universe

    International Nuclear Information System (INIS)

    Sydorenko, Maksym; Shtanov, Yuri; Tomalak, Oleksandr

    2016-01-01

    In this paper, we study analytically the process of external generation and subsequent free evolution of the lepton chiral asymmetry and helical magnetic fields in the early hot universe. This process is known to be affected by the Abelian anomaly of the electroweak gauge interactions. As a consequence, chiral asymmetry in the fermion distribution generates magnetic fields of non-zero helicity, and vice versa. We take into account the presence of thermal bath, which serves as a seed for the development of instability in magnetic field in the presence of externally generated lepton chiral asymmetry. The developed helical magnetic field and lepton chiral asymmetry support each other, considerably prolonging their mutual existence, in the process of 'inverse cascade' transferring magnetic-field power from small to large spatial scales. For cosmologically interesting initial conditions, the chiral asymmetry and the energy density of helical magnetic field are shown to evolve by scaling laws, effectively depending on a single combined variable. In this case, the late-time asymptotics of the conformal chiral chemical potential reproduces the universal scaling law previously found in the literature for the system under consideration. This regime is terminated at lower temperatures because of scattering of electrons with chirality change, which exponentially washes out chiral asymmetry. We derive an expression for the termination temperature as a function of the chiral asymmetry and energy density of helical magnetic field.

  10. North-South asymmetry of interplanetary plasma and solar parameters

    International Nuclear Information System (INIS)

    El-Borie, M. A.

    2001-01-01

    Data of interplanetary plasma (field magnitude, solar wind speed, ion plasma density and temperature) and solar parameters (sunspot number, solar radio flux, and geomagnetic index) over the period 1965-1991, have been used to examine the asymmetry between the solar field north and south of the heliospheric current sheet (HCS). The dependence of N-S asymmetry of field magnitude (B) upon the interplanetary solar polarities is statistically insignificant. There is no clear indication for the presence of N-S asymmetry in the grand-average field magnitude over the solar cycles. During the period 1981-89 (qA<0; negative solar polarity state), the solar plasma was more dense and cooler south of the HCS than north of it. The solar flux component of toward field vector is larger in magnitude than those of away field vector during the qA<0 epoch, and no asymmetry observed in the qA<0 epoch. Furthermore, the sign of the N-S asymmetry in the solar activity depends positively upon the solar polarity state. In addition, it was studied the N-S asymmetry of solar parameters near the HCS, throughout the periods of northern and southern hemispheres were more active than the other. Some asymmetries (with respect to the HCS) in plasma parameters existed during the periods of southern hemisphere predominance

  11. Shifting brain asymmetry: the link between meditation and structural lateralization.

    Science.gov (United States)

    Kurth, Florian; MacKenzie-Graham, Allan; Toga, Arthur W; Luders, Eileen

    2015-01-01

    Previous studies have revealed an increased fractional anisotropy and greater thickness in the anterior parts of the corpus callosum in meditation practitioners compared with control subjects. Altered callosal features may be associated with an altered inter-hemispheric integration and the degree of brain asymmetry may also be shifted in meditation practitioners. Therefore, we investigated differences in gray matter asymmetry as well as correlations between gray matter asymmetry and years of meditation practice in 50 long-term meditators and 50 controls. We detected a decreased rightward asymmetry in the precuneus in meditators compared with controls. In addition, we observed that a stronger leftward asymmetry near the posterior intraparietal sulcus was positively associated with the number of meditation practice years. In a further exploratory analysis, we observed that a stronger rightward asymmetry in the pregenual cingulate cortex was negatively associated with the number of practice years. The group difference within the precuneus, as well as the positive correlations with meditation years in the pregenual cingulate cortex, suggests an adaptation of the default mode network in meditators. The positive correlation between meditation practice years and asymmetry near the posterior intraparietal sulcus may suggest that meditation is accompanied by changes in attention processing. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  12. Decadal variations in geophysical processes and asymmetries in the solar motion about the Solar System's barycentre

    Science.gov (United States)

    Sidorenkov, Nikolay; Wilson, Ian; Khlystov, Anatoly

    2010-05-01

    It is well known that many geophysical processes vary on inter-annual to decadal timescales. These variations are usually attributed to terrestrial causes that include: the Earth's core-mantle coupling, the effects of internal driven stochastic oscillations in the climatic system, the effects of the global conveyer belt in World Ocean and so on. However, we contend that the empirical evidences and facts demand that this generally accepted assumption should be revised and modified. We find that the observed changes in the specific mass of the Antarctic and Greenland ice sheets closely correspond to the specific mass variations that are needed to explain the "decadal-long" fluctuations in LOD (Sidorenkov, 2009). Since the mass of the ice sheets in Antarctic and Greenland depend on long-term climate variations, it is reasonable to assume that the decadal fluctuations in the Earth's rotation may also correlate with the fluctuations in the major climatic indices. Following this line of reasoning, we have found that the atmospheric circulation regimes and the ten-year running mean of the anomalies of the Northern Hemisphere air temperature are well correlated with the changes in the Earth's rotation rate. Stanislav Perov and Nikolay Sidorenkov (2009) found also significant correlation between fluctuations in the Earth's rotational rate and activity of the India monsoon. Ian Wilson (2009) found a relationship between the deviation of the Earth's LOD from its long-term trend and the Pacific Decadal Oscillation (PDO). Whenever there are large deviations in the Earth's LOD from its long--term trend, the PDO index transitions to its positive phase. Note that the observed changes in the LOD precede those in the anomalies of the precipitation in India monsoon and in the PDO by about eight years. Ian Wilson shows that the times when Solar/Lunar tides had their greatest impact upon the Earth are closely synchronized with the times of greatest asymmetry in the Solar Inertial

  13. Age and Practice Effects on Inter-manual Performance Asymmetry

    Directory of Open Access Journals (Sweden)

    Karen L Francis

    2015-01-01

    Full Text Available Manual dexterity declines with increasing age however, the way in which inter-manual asymmetry responds to aging is unclear. Our purpose was to determine the effect of age and practice on inter-manual performance asymmetry in an isometric force pinch line tracing task that varied in difficulty within segments. Thirty right handed participants, 5 males and 5 females in each of three age groups, young (Y20, young-old (O70, and old-old (O80, practiced an isometric force pinch task for 10 trials with each hand on each of five consecutive days. Inter-manual performance asymmetry of the right and left hands was analyzed with a repeated measures ANOVA of asymmetry with age groups, practice, task difficulty, and hand as factors. The within-individual magnitude of asymmetry was also analyzed with a repeated measures ANOVA of manual asymmetry calculated as an asymmetry index (AI. Post hoc pair-wise comparisons were performed when significance was found. We observed no inter-manual performance asymmetry on this isometric tracing task among any of the age groups, either in the hand performance differences or in the magnitude of the asymmetry index (AI. Age and practice interacted in terms of manual performance: the Y20 and O70 group improved accuracy and task time across the five days of practice but the O80 group did not. However, practice did not differentially affect the AI for accuracy or task time for any group. Accuracy of performance of the two hands was differentially affected by practice. All age groups exhibited poorer performance and larger AIs on the most difficult segments of the task (3 and 6 and this did not change with practice.

  14. Entropic fluctuations in DNA sequences

    Science.gov (United States)

    Thanos, Dimitrios; Li, Wentian; Provata, Astero

    2018-03-01

    The Local Shannon Entropy (LSE) in blocks is used as a complexity measure to study the information fluctuations along DNA sequences. The LSE of a DNA block maps the local base arrangement information to a single numerical value. It is shown that despite this reduction of information, LSE allows to extract meaningful information related to the detection of repetitive sequences in whole chromosomes and is useful in finding evolutionary differences between organisms. More specifically, large regions of tandem repeats, such as centromeres, can be detected based on their low LSE fluctuations along the chromosome. Furthermore, an empirical investigation of the appropriate block sizes is provided and the relationship of LSE properties with the structure of the underlying repetitive units is revealed by using both computational and mathematical methods. Sequence similarity between the genomic DNA of closely related species also leads to similar LSE values at the orthologous regions. As an application, the LSE covariance function is used to measure the evolutionary distance between several primate genomes.

  15. Measuring the cosmological lepton asymmetry through the CMB anisotropy

    CERN Document Server

    Kinney, W H; Kinney, William H.; Riotto, Antonio

    1999-01-01

    A large lepton asymmetry in the Universe is still a viable possibility and leads to many interesting phenomena such as gauge symmetry nonrestoration at high temperature. We show that a large lepton asymmetry changes the predicted cosmic microwave background (CMB) anisotropy and that any degeneracy in the relic neutrino sea will be measured to a precision of 1% or better when the CMB anisotropy is measured at the accuracy expected to result from the planned satellite missions MAP and Planck. In fact, the current measurements already put an upper limit on the lepton asymmetry of the Universe which is stronger than the one coming from considerations of primordial nucleosynthesis and structure formation.

  16. Baryogenesis and dark matter through a Higgs asymmetry.

    Science.gov (United States)

    Servant, Géraldine; Tulin, Sean

    2013-10-11

    In addition to explaining the masses of elementary particles, the Higgs boson may have far-reaching implications for the generation of the matter content in the Universe. For instance, the Higgs boson plays a key role in two main theories of baryogenesis, namely, electroweak baryogenesis and leptogenesis. In this Letter, we propose a new cosmological scenario where the Higgs chemical potential mediates asymmetries between visible and dark matter sectors, either generating a baryon asymmetry from a dark matter asymmetry or vice versa. We illustrate this mechanism with a simple model with two new fermions coupled to the Higgs boson and discuss the associated signatures.

  17. Hydrodynamical fluctuations in smooth shear flows

    International Nuclear Information System (INIS)

    Chagelishvili, G.D.; Khujadze, G.R.; Lominadze, J.G.

    1999-11-01

    Background of hydrodynamical fluctuations in a intrinsically/stochastically forced, laminar, uniform shear flow is studied. The employment of so-called nonmodal mathematical analysis makes it possible to represent the background of fluctuations in a new light and to get more insight into the physics of its formation. The basic physical processes responsible for the formation of vortex and acoustic wave fluctuation backgrounds are analyzed. Interplay of the processes at low and moderate shear rates is described. Three-dimensional vortex fluctuations around a given macroscopic state are numerically calculated. The correlation functions of the fluctuations of physical quantities are analyzed. It is shown that there exists subspace D k in the wave-number space (k-space) that is limited externally by spherical surface with radius k ν ≡ A/ν (where A is the velocity shear parameter, ν - the kinematic viscosity) in the nonequilibrium open system under study. The spatial Fourier harmonics of vortex as well as acoustic wave fluctuations are strongly subjected by flow shear (by the open character of the system) at wave-numbers satisfying the condition k ν . Specifically it is shown that in D k : The fluctuations are non-Markovian; the spatial spectral density of energy of the vortex fluctuations by far exceeds the white-noise; the term of a new type associated to the hydrodynamical fluctuation of velocity appears in the correlation function of pressure; the fluctuation background of the acoustic waves is completely different at low and moderate shear rates (at low shear rates it is reduced in D k in comparison to the uniform (non-shear) flow; at moderate shear rates it it comparable to the background of the vortex fluctuations). The fluctuation background of both the vortex and the acoustic wave modes is anisotropic. The possible significance of the fluctuation background of vortices for the subcritical transition to turbulence and Brownian motion of small macroscopic

  18. Properties of Asymmetric Detrended Fluctuation Analysis in the time series of RR intervals

    Science.gov (United States)

    Piskorski, J.; Kosmider, M.; Mieszkowski, D.; Krauze, T.; Wykretowicz, A.; Guzik, P.

    2018-02-01

    Heart rate asymmetry is a phenomenon by which the accelerations and decelerations of heart rate behave differently, and this difference is consistent and unidirectional, i.e. in most of the analyzed recordings the inequalities have the same directions. So far, it has been established for variance and runs based types of descriptors of RR intervals time series. In this paper we apply the newly developed method of Asymmetric Detrended Fluctuation Analysis, which so far has mainly been used with economic time series, to the set of 420 stationary 30 min time series of RR intervals from young, healthy individuals aged between 20 and 40. This asymmetric approach introduces separate scaling exponents for rising and falling trends. We systematically study the presence of asymmetry in both global and local versions of this method. In this study global means "applying to the whole time series" and local means "applying to windows jumping along the recording". It is found that the correlation structure of the fluctuations left over after detrending in physiological time series shows strong asymmetric features in both magnitude, with α+ physiological data after shuffling or with a group of symmetric synthetic time series.

  19. The optimal design of UAV wing structure

    Science.gov (United States)

    Długosz, Adam; Klimek, Wiktor

    2018-01-01

    The paper presents an optimal design of UAV wing, made of composite materials. The aim of the optimization is to improve strength and stiffness together with reduction of the weight of the structure. Three different types of functionals, which depend on stress, stiffness and the total mass are defined. The paper presents an application of the in-house implementation of the evolutionary multi-objective algorithm in optimization of the UAV wing structure. Values of the functionals are calculated on the basis of results obtained from numerical simulations. Numerical FEM model, consisting of different composite materials is created. Adequacy of the numerical model is verified by results obtained from the experiment, performed on a tensile testing machine. Examples of multi-objective optimization by means of Pareto-optimal set of solutions are presented.

  20. Adjoint-based optimization for flapping wings

    Science.gov (United States)

    Xu, Min; Wei, Mingjun

    2012-11-01

    Adjoint-based methods show great potential in flow control and optimization of complex problems with high- or infinite-dimensional control space. It is attractive to solve an adjoint problem to understand the complex effects from multiple control parameters to a few performance indicators of the flight of birds or insects. However, the traditional approach to formulate the adjoint problem becomes either impossible or too complex when arbitrary moving boundary (e.g. flapping wings) and its perturbation is considered. Here, we use non-cylindrical calculus to define the perturbation. So that, a simple adjoint system can be derived directly in the inertial coordinate. The approach is first applied to the optimization of cylinder oscillation and later to flapping wings. Supported by AFOSR.

  1. Quantifying the dynamic wing morphing of hovering hummingbird.

    Science.gov (United States)

    Maeda, Masateru; Nakata, Toshiyuki; Kitamura, Ikuo; Tanaka, Hiroto; Liu, Hao

    2017-09-01

    Animal wings are lightweight and flexible; hence, during flapping flight their shapes change. It has been known that such dynamic wing morphing reduces aerodynamic cost in insects, but the consequences in vertebrate flyers, particularly birds, are not well understood. We have developed a method to reconstruct a three-dimensional wing model of a bird from the wing outline and the feather shafts (rachides). The morphological and kinematic parameters can be obtained using the wing model, and the numerical or mechanical simulations may also be carried out. To test the effectiveness of the method, we recorded the hovering flight of a hummingbird ( Amazilia amazilia ) using high-speed cameras and reconstructed the right wing. The wing shape varied substantially within a stroke cycle. Specifically, the maximum and minimum wing areas differed by 18%, presumably due to feather sliding; the wing was bent near the wrist joint, towards the upward direction and opposite to the stroke direction; positive upward camber and the 'washout' twist (monotonic decrease in the angle of incidence from the proximal to distal wing) were observed during both half-strokes; the spanwise distribution of the twist was uniform during downstroke, but an abrupt increase near the wrist joint was found during upstroke.

  2. Optimization of aerodynamic efficiency for twist morphing MAV wing

    Directory of Open Access Journals (Sweden)

    N.I. Ismail

    2014-06-01

    Full Text Available Twist morphing (TM is a practical control technique in micro air vehicle (MAV flight. However, TM wing has a lower aerodynamic efficiency (CL/CD compared to membrane and rigid wing. This is due to massive drag penalty created on TM wing, which had overwhelmed the successive increase in its lift generation. Therefore, further CL/CDmax optimization on TM wing is needed to obtain the optimal condition for the morphing wing configuration. In this paper, two-way fluid–structure interaction (FSI simulation and wind tunnel testing method are used to solve and study the basic wing aerodynamic performance over (non-optimal TM, membrane and rigid wings. Then, a multifidelity data metamodel based design optimization (MBDO process is adopted based on the Ansys-DesignXplorer frameworks. In the adaptive MBDO process, Kriging metamodel is used to construct the final multifidelity CL/CD responses by utilizing 23 multi-fidelity sample points from the FSI simulation and experimental data. The optimization results show that the optimal TM wing configuration is able to produce better CL/CDmax magnitude by at least 2% than the non-optimal TM wings. The flow structure formation reveals that low TV strength on the optimal TM wing induces low CD generation which in turn improves its overall CL/CDmax performance.

  3. Logistics Supply of the Distributed Air Wing

    Science.gov (United States)

    2014-09-01

    Event Graph The Consumption Process first instantiates the variables . The model follows a conveyor belt pattern, whereby after processing an event...to any part of the world. A capstone project, conducted by the system engineering curriculum, proposed to distribute the air assets from the aircraft...SUBJECT TERMS distributed air wing, logistics, supply, unmanned air systems , cargo UAS, unmanned systems , discrete event simulation, vehicle routing

  4. CFD Analysis of UAV Flying Wing

    Directory of Open Access Journals (Sweden)

    Vasile PRISACARIU

    2016-09-01

    Full Text Available Numerical methods for solving equations describing the evolution of 3D fluid experienced a significant development closely related to the progress of information systems. Today, especially in the field of fluid mechanics, numerical simulations allow the study of gas-thermodynamic confirmed by experimental techniques in wind tunnel conditions and actual flight tests for modeling complex aircraft. The article shows a case of numerical analysis of the lifting surface on the UAV type flying wing.

  5. Topology Optimization of an Aircraft Wing

    Science.gov (United States)

    2015-06-11

    can combine the advantages of a variable stiffness design with- out the use of actuators. Curved beams, which couple torsion and bending , counteract... torsional deflection, control natural frequency, exploit coupling of bending and tor- sion to control flutter, reduce thickness to chord ratios due to...disregarded any bending or torsional effects caused by displacement of the wing, and was thus not considered. Therefore, the initial design analysis

  6. Supersymmetry protects the primordial baryon asymmetry

    CERN Document Server

    Ibáñez, L E; Ibanez, Luis E.; Quevedo, Fernando

    1992-01-01

    It has been argued that any primordial B+L asymmetry existing at very high temperatures can be subsequently erased by anomalous electroweak effects. We argue that this is not necessarily the case in the supersymmetric standard model because, apart from B and/or L, there are, above a certain temperature $T_{SS}$, two other anomalous U(1) currents. As a consequence, anomalous electroweak effects are only able to partially transform a B+L excess into a generation of primordial sparticle (e.g. gaugino) density. This relaxes recent bounds on B,L-violating non-renormalizable couplings by several orders of magnitude. In particular, dimension-5 couplings inducing neutrino masses may be 4 orders of magnitude larger than in the non-supersymmetric case, allowing for neutrino masses of the order of 10 eV. These values are consistent with a MSW+see-saw explanation of the solar-neutrino data and also with possible neutrino oscillations measurable at accelerators. Cosmological bounds on other rare processes, such as neutron...

  7. CP asymmetries in Strange Baryon Decays

    Science.gov (United States)

    Bigi, I. I.; Kang, Xian-Wei; Li, Hai-Bo

    2018-01-01

    While indirect and direct CP violation (CPV) has been established in the decays of strange and beauty mesons, no CPV has yet been found for baryons. There are different paths to finding CP asymmetry in the decays of strange baryons; they are all highly non-trivial. The HyperCP Collaboration has probed CPV in the decays of single Ξ and Λ [1]. We discuss future lessons from {{{e}}}+{{{e}}}- collisions at BESIII/BEPCII: probing decays of pairs of strange baryons, namely Λ, Σ and Ξ. Realistic goals are to learn about non-perturbative QCD. One can hope to find CPV in the decays of strange baryons; one can also dream of finding the impact of New Dynamics. We point out that an important new era will start with the BESIII/BEPCII data accumulated by the end of 2018. This also supports new ideas to trigger {{J}}/{{\\psi }}\\to \\bar{{{Λ }}}{{Λ }} at the LHCb collaboration. Supported by National Science Foundation (PHY-1520966), National Natural Science Foundation of China (11335009, 11125525), Joint Large-Scale Scientific Facility Funds of the NSFC and CAS (U1532257), the National Key Basic Research Program of China (2015CB856700), Key Research Program of Frontier Sciences, CAS, (QYZDJ-SSW-SLH003), XWK’s work is also supported by MOST (Taiwan) (104-2112-M-001-022)

  8. The Lateralizing Asymmetry of Adrenal Adenomas

    Science.gov (United States)

    Hao, Meng; Lopez, Diana; Luque-Fernandez, Miguel Angel; Cote, Kathryn; Newfield, Jessica; Connors, Molly; Vaidya, Anand

    2018-01-01

    Abstract Context It is presumed that the incidence of adrenal adenomas is symmetric between the left and right adrenal gland; however, anecdotal observations suggest a potential lateralizing asymmetry. Objective To investigate the symmetry in detection of adrenal adenomas and relevance to patient care. Design Cross-sectional and longitudinal studies. Population and Setting One thousand three hundred seventy-six patients with abdominal computed tomography or magnetic resonance imaging demonstrating benign-appearing adrenal adenomas. Main Outcome Location and size of adrenal adenomas. Results Left-sided adenomas were discovered in 65% of patients, right-sided in 21%, and bilateral adenomas in 14%. Among unilateral adenomas, 75% were left-sided. Left-sided adenomas were more prevalent than right-sided adenomas in each size category except the largest: Adrenal adenomas are substantially more likely to be identified on the left adrenal than the right. This observation may be due to detection bias attributed to the location of the right adrenal, which may preclude identification of right-sided adenomas until they are substantially larger. These findings suggest the potential for an underrecognition of right-sided adenomas that may also impair the accurate detection of bilateral adrenal diseases. PMID:29644340

  9. Asymmetries of the solar Ca II lines

    International Nuclear Information System (INIS)

    Heasley, J.N.

    1975-01-01

    A theoretical study of the influence of propagating acoustic pulses in the solar chromosphere upon the line profiles of the Ca II resonance and infrared triplet lines has been made. The major objective has been to explain the observed asymmetries seen in the cores of the H and K lines and to predict the temporal behavior of the infrared lines caused by passing acoustic or shock pulses. The velocities in the pulses, calculated from weak shock theory, have been included consistently in the non-LTE calculations. The results of the calculations show that these lines are very sensitive to perturbations in the background atmosphere caused by the pulses. Only minor changes in the line shapes result from including the velocities consistently in the line source function calculations. The qualitative changes in the line profiles vary markedly with the strength of the shock pulses. The observed differences in the K line profiles seen on the quiet Sun can be explained in terms of a spectrum of pulses with different wavelengths and initial amplitudes in the photosphere. (Auth.)

  10. Bet Hedging against Demographic Fluctuations

    Science.gov (United States)

    Xue, BingKan; Leibler, Stanislas

    2017-09-01

    Biological organisms have to cope with stochastic variations in both the external environment and the internal population dynamics. Theoretical studies and laboratory experiments suggest that population diversification could be an effective bet-hedging strategy for adaptation to varying environments. Here we show that bet hedging can also be effective against demographic fluctuations that pose a trade-off between growth and survival for populations even in a constant environment. A species can maximize its overall abundance in the long term by diversifying into coexisting subpopulations of both "fast-growing" and "better-surviving" individuals. Our model generalizes statistical physics models of birth-death processes to incorporate dispersal, during which new populations are founded, and can further incorporate variations of local environments. In this way, we unify different bet-hedging strategies against demographic and environmental variations as a general means of adaptation to both types of uncertainties in population growth.

  11. Characterizing flow fluctuations with moments

    Directory of Open Access Journals (Sweden)

    Rajeev S. Bhalerao

    2015-03-01

    Full Text Available We present a complete set of multiparticle correlation observables for ultrarelativistic heavy-ion collisions. These include moments of the distribution of the anisotropic flow in a single harmonic and also mixed moments, which contain the information on correlations between event planes of different harmonics. We explain how all these moments can be measured using just two symmetric subevents separated by a rapidity gap. This presents a multi-pronged probe of the physics of flow fluctuations. For instance, it allows to test the hypothesis that event-plane correlations are generated by non-linear hydrodynamic response. We illustrate the method with simulations of events in A MultiPhase Transport (AMPT model.

  12. Fluctuating nonlinear hydrodynamics of flocking

    Science.gov (United States)

    Yadav, Sunil Kumar; Das, Shankar P.

    2018-03-01

    Starting from a microscopic model, the continuum field theoretic description of the dynamics of a system of active ingredients or "particles" is presented. The equations of motion for the respective collective densities of mass and momentum follow exactly from that of a single element in the flock. The single-particle dynamics has noise and anomalous momentum dependence in its frictional terms. The equations for the collective densities are averaged over a local equilibrium distribution to obtain the corresponding coarse grained equations of fluctuating nonlinear hydrodynamics (FNH). The latter are the equations used frequently for describing active systems on the basis of intuitive arguments. The transport coefficients which appear in the macroscopic FNH equations are determined in terms of the parameters of the microscopic dynamics.

  13. Cerebral blood flow asymmetries in headache-free migraineurs

    International Nuclear Information System (INIS)

    Levine, S.R.; Welch, K.M.; Ewing, J.R.; Joseph, R.; D'Andrea, G.

    1987-01-01

    Regional cerebral blood flow (rCBF) asymmetries were studied in controls and patients with common and classic/complicated migraine using 133 Xe inhalation with 8 homologously situated external collimators over each cerebral hemisphere. Migraine patients as a group more frequently had posterior rCBF asymmetries than controls (p less than 0.03). Although there were no differences in the number of anterior rCBF asymmetries, migraine patients had 2 or more asymmetric probe pairs more often than controls (p less than 0.02). The posterior rCBF asymmetries, consistent with the site of activation of many migraine attacks, may be related to more labile control of the cerebral circulation

  14. Axial asymmetry, finite particle number and the IBA

    International Nuclear Information System (INIS)

    Casten, R.F.

    1984-01-01

    Although the IBA-1 contains no solutions corresponding to a rigid triaxial shape, it does contain an effective asymmetry. This arises from zero point motion in a γ-soft potential leading to a non-zero mean or rms γ. Three aspects of this feature will be discussed: (1) The relation between IBA-1 calculations and the corresponding γ. This point is developed in the context of the Consistent Q Formalism (CQF) of the IBA. (2) The dependence of this asymmetry on boson number, N, and the exploitation of this dependence to set limits on both the relative and absolute values of N for deformed nuclei. (3) The relation between this asymmetry and the triaxiality arising from the introduction of cubic terms into the IBA Hamiltonian. Various observables will be inspected in order both to determine their sensitivity to these two structural features and to explore empirical ways of distinguishing which origin of asymmetry applies in any given nucleus. 16 references

  15. Analysis of Resonance Asymmetry Phenomenon in Resonant Fiber Optic Gyro

    Directory of Open Access Journals (Sweden)

    Zhuoyan Li

    2018-02-01

    Full Text Available This experiment demonstrated the resonance asymmetry phenomenon in the resonant fiber optic gyro. The asymmetry of resonant curve affects the system open-loop bias and its stability, which directly affects the accuracy of angular velocity measurement. In this paper, a new mathematic model is established. The influence of the coupler normal mode loss difference (the phase difference between the coupler cross port output optical field and direct port is less than the ideal π/2 on the symmetry of resonant curve, the resonant signal modulated by the triangular wave, and the demodulation curve are analyzed. Moreover, the asymmetry of the resonant curve leads to the asymmetry of the resonant signal, as modulated by the triangular wave and the demodulation curve from the theoretical simulation and the experiment.

  16. Analysis of Resonance Asymmetry Phenomenon in Resonant Fiber Optic Gyro.

    Science.gov (United States)

    Li, Zhuoyan; He, Nie; Sun, Xuqiang; Jin, Chao; Liu, Chengxiang; Wu, Xu

    2018-02-26

    This experiment demonstrated the resonance asymmetry phenomenon in the resonant fiber optic gyro. The asymmetry of resonant curve affects the system open-loop bias and its stability, which directly affects the accuracy of angular velocity measurement. In this paper, a new mathematic model is established. The influence of the coupler normal mode loss difference (the phase difference between the coupler cross port output optical field and direct port is less than the ideal π/2) on the symmetry of resonant curve, the resonant signal modulated by the triangular wave, and the demodulation curve are analyzed. Moreover, the asymmetry of the resonant curve leads to the asymmetry of the resonant signal, as modulated by the triangular wave and the demodulation curve from the theoretical simulation and the experiment.

  17. Flavor versus mass eigenstates in neutrino asymmetries: implications for cosmology

    Energy Technology Data Exchange (ETDEWEB)

    Barenboim, Gabriela [Universitat de Valencia-CSIC, Departament de Fisica Teorica y IFIC, Burjassot (Spain); Kinney, William H. [University at Buffalo, Department of Physics, Buffalo, NY (United States); Park, Wan-Il [Universitat de Valencia-CSIC, Departament de Fisica Teorica y IFIC, Burjassot (Spain); Chonbuk National University, Division of Science Education and Institute of Fusion Science, Jeonju (Korea, Republic of)

    2017-09-15

    We show that, if they exist, lepton number asymmetries (L{sub α}) of neutrino flavors should be distinguished from the ones (L{sub i}) of mass eigenstates, since Big Bang Nucleosynthesis (BBN) bounds on the flavor eigenstates cannot be directly applied to the mass eigenstates. Similarly, Cosmic Microwave Background (CMB) constraints on the mass eigenstates do not directly constrain flavor asymmetries. Due to the difference of mass and flavor eigenstates, the cosmological constraint on the asymmetries of neutrino flavors can be much stronger than the conventional expectation, but they are not uniquely determined unless at least the asymmetry of the heaviest neutrino is well constrained. The cosmological constraint on L{sub i} for a specific case is presented as an illustration. (orig.)

  18. Hemispheric asymmetry in the influence of language on visual perception.

    Science.gov (United States)

    Sun, Yanliang; Cai, Yongchun; Lu, Shena

    2015-07-01

    Many studies have shown that language can affect visual perception; however, our understanding of the neural basis of linguistic influence is inadequate. This can be investigated by examining the hemispheric asymmetry of linguistic influence. The left and right hemispheres are dominant in close and distant semantic processing, respectively. In this study, we investigated whether the hemispheric asymmetry of semantic processing led to hemispheric asymmetry for concept priming on the detection of objects degraded by continuous flash suppression. We combined a priming paradigm with the divided visual field paradigm and used continuous flash suppression, which renders objects invisible. The results indicated that the hemispheric asymmetry of semantic processing led to a right lateralization in the influence of more abstract concepts on visual perception. The lateralization of brain connectomes may be the underlying neural basis of this effect. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Tracing the evolution of avian wing digits.

    Science.gov (United States)

    Xu, Xing; Mackem, Susan

    2013-06-17

    It is widely accepted that birds are a subgroup of dinosaurs, but there is an apparent conflict: modern birds have been thought to possess only the middle three fingers (digits II-III-IV) of an idealized five-digit tetrapod hand based on embryological data, but their Mesozoic tetanuran dinosaur ancestors are considered to have the first three digits (I-II-III) based on fossil evidence. How could such an evolutionary quirk arise? Various hypotheses have been proposed to resolve this paradox. Adding to the confusion, some recent developmental studies support a I-II-III designation for avian wing digits whereas some recent paleontological data are consistent with a II-III-IV identification of the Mesozoic tetanuran digits. A comprehensive analysis of both paleontological and developmental data suggests that the evolution of the avian wing digits may have been driven by homeotic transformations of digit identity, which are more likely to have occurred in a partial and piecemeal manner. Additionally, recent genetic studies in mouse models showing plausible mechanisms for central digit loss invite consideration of new alternative possibilities (I-II-IV or I-III-IV) for the homologies of avian wing digits. While much progress has been made, some advances point to the complexity of the problem and a final resolution to this ongoing debate demands additional work from both paleontological and developmental perspectives, which will surely yield new insights on mechanisms of evolutionary adaptation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Unsteady fluid dynamics around a hovering wing

    Science.gov (United States)

    Krishna, Swathi; Green, Melissa; Mulleners, Karen

    2017-11-01

    The unsteady flow around a hovering flat plate wing has been investigated experimentally using particle image velocimetry and direct force measurements. The measurements are conducted on a wing that rotates symmetrically about the stroke reversal at a reduced frequency of k = 0.32 and Reynolds number of Re = 220 . The Lagrangian finite-time Lyapunov exponent method is used to analyse the unsteady flow fields by identifying dynamically relevant flow features such as the primary leading edge vortex (LEV), secondary vortices, and topological saddles, and their evolution within a flapping cycle. The flow evolution is divided into four stages that are characterised by the LEV (a)emergence, (b)growth, (c)lift-off, and (d)breakdown and decay. Tracking saddle points is shown to be helpful in defining the LEV lift-off which occurs at the maximum stroke velocity. The flow fields are correlated with the aerodynamic forces revealing that the maximum lift and drag are observed just before LEV lift-off. The end of wing rotation in the beginning of the stroke stimulates a change in the direction of the LEV growth and the start of rotation at the end of the stroke triggers the breakdown of the LEV.

  1. Interplanetary Alfvenic fluctuations: A stochastic model

    International Nuclear Information System (INIS)

    Barnes, A.

    1981-01-01

    The strong alignment of the average directions of minimum magnetic variance and mean magnetic field in interplanetary Alfvenic fluctuations is inconsistent with the usual wave-propagation models. We investigate the concept of minimum variance for nonplanar Alfvenic fluctuations in which the field direction varies stochastically. It is found that the tendency of the minimum variance and mean field directions to be aligned may be purely a consequence of the randomness of the field direction. In particular, a well-defined direction of minimum variance does not imply that the fluctuations are necessarily planar. The fluctuation power spectrum is a power law for frequencies much higher than the inverse of the correlation time. The probability distribution of directions a randomly fluctuating field of constant magnitude is calculated. A new approach for observational studies of interplanetary fluctuations is suggested

  2. Tuning piezoresistive transduction in nanomechanical resonators by geometrical asymmetries

    Energy Technology Data Exchange (ETDEWEB)

    Llobet, J.; Sansa, M.; Lorenzoni, M.; Pérez-Murano, F., E-mail: francesc.perez@csic.es [Institut de Microelectrònica de Barcelona (IMB-CNM CSIC), Campus UAB, 08193 Bellaterra (Spain); Borrisé, X. [Institut Català de Nanociència i Nanotecnologia (ICN2), Campus UAB, 08193 Bellaterra Spain (Spain); San Paulo, A. [Instituto de Microelectrónica de Madrid (IMM-CSIC), 28760 Tres Cantos, Madrid (Spain)

    2015-08-17

    The effect of geometrical asymmetries on the piezoresistive transduction in suspended double clamped beam nanomechanical resonators is investigated. Tapered silicon nano-beams, fabricated using a fast and flexible prototyping method, are employed to determine how the asymmetry affects the transduced piezoresistive signal for different mechanical resonant modes. This effect is attributed to the modulation of the strain in pre-strained double clamped beams, and it is confirmed by means of finite element simulations.

  3. The 'Goldilocks Zone': getting the measure of manual asymmetries.

    Directory of Open Access Journals (Sweden)

    Rachael K Raw

    Full Text Available Some studies have shown that manual asymmetries decrease in older age. These results have often been explained with reference to models of reduced hemispheric specialisation. An alternative explanation, however, is that hand differences are subtle, and capturing them requires tasks that yield optimal performance with both hands. Whereas the hemispheric specialisation account implies that reduced manual asymmetries should be reliably observed in older adults, the 'measurement difficulty' account suggests that manual asymmetries will be hard to detect unless a task has just the right level of difficulty--i.e. within the 'Goldilocks Zone', where it is not too easy or too hard, but just right. Experiment One tested this hypothesis and found that manual asymmetries were only detected when participants performed in this zone; specifically, performance on a tracing task was only superior in the preferred hand when task constraints were high (i.e. fast speed tracing. Experiment Two used three different tasks to examine age differences in manual asymmetries; one task produced no asymmetries, whilst two tasks revealed asymmetries in both younger and older groups (with poorer overall performance in the old group across all tasks. Experiment Three revealed task-dependent asymmetries in both age groups, but highlighted further detection difficulties linked with the metric of performance and compensatory strategies used by participants. Results are discussed with reference to structural learning theory, whereby we suggest that the processes of inter-manual transfer lead to relatively small performance differences between the hands (despite a strong phenomenological sense of performance disparities.

  4. Polarization asymmetries and gauge theory interactions at short distances

    International Nuclear Information System (INIS)

    Craigie, N.S.

    1983-01-01

    In this talk, we give the arguments as to why spin asymmetries test fundamental properties of the underlying gauge theories of elementary particles, concentrating mainly on electro-weak and QCD interactions, but also looking at the future and possible signatures for supersymmetric strong interactions. We also mention briefly the role helicity asymmetry measurements can play as regards higher order corrections, including higher twist, in QCD. (orig./HSI)

  5. Kinetic Asymmetry during Running at Preferred and Nonpreferred Speeds.

    Science.gov (United States)

    Furlong, Laura-Anne M; Egginton, Natalie L

    2018-01-23

    The aim of this study was to investigate the effect of altering preferred running speed by ±20% on kinetic asymmetry. Three-dimensional motion analysis and force data were acquired from 15 healthy males (age: 27 ± 4.6 years, height: 1.81 ± 0.09 m, mass: 80.4 ± 12.4 kg) during their preferred running speed, and at ±20% of this speed. 3T magnetic resonance images were used to measure Achilles tendon cross-sectional area and moment arm, for use in calculation of tendon stress. Kinetic and tendon stress asymmetry were subsequently calculated in each condition using the symmetry index. Across all joints and conditions, average asymmetry of peak moments was between ±6% but higher individual values were observed; there was no effect of speed on magnitude of asymmetry. Ground contact times, vertical ground reaction forces and support and ankle moments (maximum absolute asymmetry: 9%) were more symmetrical than hip and knee moments (up to 18%). Individual joint contribution to support moment and positive work were similar in both limbs, and ankle and hip compensatory interactions were observed with alterations in running speed. Achilles tendon stress increased with increased running speed, with higher stress in the preferred limb; asymmetry in tendon stress was not related to asymmetry in vertical ground reaction forces. Results show small effects of altering running speed on kinetic asymmetry, but responses are individual-specific with interactions occurring between joints to maintain overall movement symmetry. Further research is needed to understand the mechanical and neuromuscular mechanisms underpinning these compensations.

  6. The validity of individual frontal alpha asymmetry EEG neurofeedback.

    Science.gov (United States)

    Quaedflieg, C W E M; Smulders, F T Y; Meyer, T; Peeters, F; Merckelbach, H; Smeets, T

    2016-01-01

    Frontal asymmetry in alpha oscillations is assumed to be associated with psychopathology and individual differences in emotional responding. Brain-activity-based feedback is a promising tool for the modulation of cortical activity. Here, we validated a neurofeedback protocol designed to change relative frontal asymmetry based on individual alpha peak frequencies, including real-time average referencing and eye-correction. Participants (N = 60) were randomly assigned to a right, left or placebo neurofeedback group. Results show a difference in trainability between groups, with a linear change in frontal alpha asymmetry over time for the right neurofeedback group during rest. Moreover, the asymmetry changes in the right group were frequency and location specific, even though trainability did not persist at 1 week and 1 month follow-ups. On the behavioral level, subjective stress on the second test day was reduced in the left and placebo neurofeedback groups, but not in the right neurofeedback group. We found individual differences in trainability that were dependent on training group, with participants in the right neurofeedback group being more likely to change their frontal asymmetry in the desired direction. Individual differences in trainability were also reflected in the ability to change frontal asymmetry during the feedback. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  7. Role of quasiprojectile isospin asymmetry in nuclear fragmentation

    International Nuclear Information System (INIS)

    Tripathi, R.; Bonasera, A.; Wuenschel, S.

    2012-01-01

    Fragment yield data, selected with different values of the isospin asymmetry of the quasiprojectile from 78, 86 Kr + 58, 64 Ni reactions at E lab = 35 MeV/nucleon, have been analyzed within the framework of Landau free energy approach. Fits to the free energy data indicated the system to be in the regime of a first-order phase transition. The plot of free energy versus isospin asymmetry of the fragments showed a systematic change with increasing isospin asymmetry of the fragmenting source. This observation demonstrated the role of quasiprojectile isospin asymmetry as an external field which governed the minima positions in the free energy plot. The position of the central minimum was found to be in close agreement with the average isospin asymmetry of the fragments calculated excluding neutrons and protons. Significant deviations from the free energy plot were observed for N = Z fragments, particularly for the lighter ones, which could be corrected after inclusion of odd–even effects in the analysis. Analysis of yield data of N = Z nuclei gave a reasonable estimate of temperature. Analysis of free energy data gated with excitation energy of the fragmenting source showed a dependence of fit parameters of Landau free energy equation on the excitation energy as well as isospin asymmetry of the source. (author)

  8. Integral fluctuation theorems for stochastic resetting systems

    Science.gov (United States)

    Pal, Arnab; Rahav, Saar

    2017-12-01

    We study the stochastic thermodynamics of resetting systems. Violation of microreversibility means that the well-known derivations of fluctuations theorems break down for dynamics with resetting. Despite that we show that stochastic resetting systems satisfy two integral fluctuation theorems. The first is the Hatano-Sasa relation describing the transition between two steady states. The second integral fluctuation theorem involves a functional that includes both dynamical and thermodynamic contributions. We find that the second law-like inequality found by Fuchs et al. for resetting systems [Europhys. Lett. 113, 60009 (2016), 10.1209/0295-5075/113/60009] can be recovered from this integral fluctuation theorem with the help of Jensen's inequality.

  9. Fluctuations in percolation of sparse complex networks

    Science.gov (United States)

    Bianconi, Ginestra

    2017-07-01

    We study the role of fluctuations in percolation of sparse complex networks. To this end we consider two random correlated realizations of the initial damage of the nodes and we evaluate the fraction of nodes that are expected to remain in the giant component of the network in both cases or just in one case. Our framework includes a message-passing algorithm able to predict the fluctuations in a single network, and an analytic prediction of the expected fluctuations in ensembles of sparse networks. This approach is applied to real ecological and infrastructure networks and it is shown to characterize the expected fluctuations in their response to external damage.

  10. Neutrino propagation in a fluctuating sun

    International Nuclear Information System (INIS)

    Burgess, C.P.; Michaud, D.

    1997-01-01

    We adapt to neutrino physics a general formulation for particle propagation in fluctuating media, initially developed for applications to electromagnetism and neutron optics. In leading approximation this formalism leads to the usual MSW effective Hamiltonian governing neutrino propagation through a medium. Next-to-leading contributions describe deviations from this description, which arise due to neutrino interactions with fluctuations in the medium. We compute these corrections for two types of fluctuations: (i) microscopic thermal fluctuations and (ii) macroscopic fluctuations in the medium s density. While the first of these reproduces standard estimates, which are negligible for applications to solar neutrinos, we find that the second can be quite large, since it grows in size with the correlation length of the fluctuation. We consider two models in some detail. For fluctuations whose correlations extend only over a local region in space of length l, appreciable effects for MSW oscillations arise if (δn/n) 2 l approx-gt 100m or so. Alternatively, a crude model of helioseismic p-waves gives appreciable effects only when (δn/n)approx-gt 1%. In general the dominant effect is to diminish the quality of the resonance, making the suppression of the 7 Be neutrinos a good experimental probe of fluctuations deep within the sun. Fluctuations can also provide a new mechanism for reducing the solar neutrino flux, giving an energy-independent suppression factor of 1/2 away from the resonant region, even for small vacuum mixing angles. copyright 1997 Academic Press, Inc

  11. Wing geometry of Triatoma sordida (Hemiptera: Reduviidae) populations from Brazil.

    Science.gov (United States)

    Vendrami, Daniel Pagotto; Obara, Marcos Takashi; Gurgel-Gonçalves, Rodrigo; Ceretti-Junior, Walter; Marrelli, Mauro Toledo

    2017-04-01

    Triatoma sordida has a widespread distribution in Argentina, Bolivia, Brazil, Paraguay, and Uruguay and is frequently found in peridomestic environments. We investigated size and shape variability of T. sordida wings across Brazil. Field-collected adults from twelve populations were studied. For each individual female, seven landmarks on the right wing were digitalized. Shape variables derived from Procrustes superimposition were used in Principal Component Analysis (PCA). Wing size and shape variations among populations was explored by means of ANOVA. Wing centroid size was significantly different among T. sordida populations; specimens from Bahia (East) were larger than those of Mato Grosso do Sul (West). PCA based on wing shape variables showed low wing shape variability. These results reinforce previous data showing low genetic variability among T. sordida populations from Brazil. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Measurement of shape and deformation of insect wing

    Science.gov (United States)

    Yin, Duo; Wei, Zhen; Wang, Zeyu; Zhou, Changqiu

    2018-01-01

    To measure the shape and deformation of an insect wing, a scanning setup adopting laser triangulation and image matching was developed. Only one industry camera with two light sources was employed to scan the transparent insect wings. 3D shape and point to point full field deformation of the wings could be obtained even when the wingspan is less than 3 mm. The venation and corrugation could be significantly identified from the results. The deformation of the wing under pin loading could be seen clearly from the results as well. Calibration shows that the shape and deformation measurement accuracies are no lower than 0.01 mm. Laser triangulation and image matching were combined dexterously to adapt wings' complex shape, size, and transparency. It is suitable for insect flight research or flapping wing micro-air vehicle development.

  13. Free vibration analysis of dragonfly wings using finite element method

    OpenAIRE

    M Darvizeh; A Darvizeh; H Rajabi; A Rezaei

    2016-01-01

    In the present work, investigations on the microstructure and mechanicalproperties of the dragonfly wing are carried out and numerical modelingbased on Finite Element Method (FEM) is developed to predict Flightcharacteristics of dragonfly wings. Vibrational behavior of wings typestructures is immensely important in analysis, design and manufacturing ofsimilar engineering structures. For this purpose natural frequencies andmode shapes are calculated. In addition, the kind of deformation in eac...

  14. Nanocrystal Bioassembly: Asymmetry, Proximity, and Enzymatic Manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Claridge, Shelley A. [Univ. of California, Berkeley, CA (United States)

    2008-05-01

    Research at the interface between biomolecules and inorganic nanocrystals has resulted in a great number of new discoveries. In part this arises from the synergistic duality of the system: biomolecules may act as self-assembly agents for organizing inorganic nanocrystals into functional materials; alternatively, nanocrystals may act as microscopic or spectroscopic labels for elucidating the behavior of complex biomolecular systems. However, success in either of these functions relies heavily uponthe ability to control the conjugation and assembly processes.In the work presented here, we first design a branched DNA scaffold which allows hybridization of DNA-nanocrystal monoconjugates to form discrete assemblies. Importantly, the asymmetry of the branched scaffold allows the formation of asymmetric2assemblies of nanocrystals. In the context of a self-assembled device, this can be considered a step toward the ability to engineer functionally distinct inputs and outputs.Next we develop an anion-exchange high performance liquid chromatography purification method which allows large gold nanocrystals attached to single strands of very short DNA to be purified. When two such complementary conjugates are hybridized, the large nanocrystals are brought into close proximity, allowing their plasmon resonances to couple. Such plasmon-coupled constructs are of interest both as optical interconnects for nanoscale devices and as `plasmon ruler? biomolecular probes.We then present an enzymatic ligation strategy for creating multi-nanoparticle building blocks for self-assembly. In constructing a nanoscale device, such a strategy would allow pre-assembly and purification of components; these constructs can also act as multi-label probes of single-stranded DNA conformational dynamics. Finally we demonstrate a simple proof-of-concept of a nanoparticle analog of the polymerase chain reaction.

  15. Structural hemispheric asymmetries underlie verbal Stroop performance.

    Science.gov (United States)

    Vallesi, Antonino; Mazzonetto, Ilaria; Ambrosini, Ettore; Babcock, Laura; Capizzi, Mariagrazia; Arbula, Sandra; Tarantino, Vincenza; Semenza, Carlo; Bertoldo, Alessandra

    2017-09-29

    Performance on tasks involving cognitive control such as the Stroop task is often associated with left lateralized brain activations. Based on this neuro-functional evidence, we tested whether leftward structural grey matter asymmetries would also predict inter-individual differences in combatting Stroop interference. To check for the specificity of the results, both a verbal Stroop task and a spatial one were administered to a total of 111 healthy young individuals, for whom T1-weighted magnetic resonance imaging (MRI) images were also acquired. Surface thickness and area estimations were calculated using FreeSurfer. Participants' hemispheres were registered to a symmetric template and Laterality Indices (LI) for the surface thickness and for the area at each vertex in each participant were computed. The correlation of these surface LI measures with the verbal and spatial Stroop effects (incongruent-congruent difference in trial performance) was assessed at each vertex by means of general linear models at the whole-brain level. We found a significant correlation between performance and surface area LI in an inferior posterior temporal cluster (overlapping with the so-called visual word form area, VWFA), with a more left-lateralized area in this region associated with a smaller Stroop effect only in the verbal task. These results point to an involvement of the VWFA for higher-level processes based on word reading, including the suppression of this process when required by the task, and could be interpreted in the context of cross-hemispheric rivalry. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Investigation and design of a C-Wing passenger aircraft

    Directory of Open Access Journals (Sweden)

    Karan BIKKANNAVAR

    2016-06-01

    Full Text Available A novel nonplanar wing concept called C-Wing is studied and implemented on a commercial aircraft to reduce induced drag which has a significant effect on fuel consumption. A preliminary sizing method which employs an optimization algorithm is utilized. The Airbus A320 aircraft is used as a reference aircraft to evaluate design parameters and to investigate the C-Wing design potential beyond current wing tip designs. An increase in aspect ratio due to wing area reduction at 36m span results in a reduction of required fuel mass by 16%. Also take-off mass savings were obtained for the aircraft with C-Wing configuration. The effect of a variations of height to span ratio (h/b of C-Wings on induced drag factor k, is formulated from a vortex lattice method and literature based equations. Finally the DOC costing methods used by the Association of European Airlines (AEA was applied to the existing A320 aircraft and to the C-Wing configuration obtaining a reduction of 6% in Direct Operating Costs (DOC for the novel concept resulted. From overall outcomes, the C-Wing concept suggests interesting aerodynamic efficiency and stability benefits.

  17. Effects of Canard on the Flowfield over a Wing

    Science.gov (United States)

    Nayebzadeh, Arash

    2015-11-01

    Surface and flowfield pressure measurements have been done over delta wing/canard configuration in a variety of canard vertical and horizontal locations and angles of attack. The experimental model consisted of wing, canard and a body to accommodate pressure tubing and canard rotation mechanism. All the tests have been performed at subsonic velocities and the effect of canard were analyzed through comparison between surface and flowfield pressure distributions. It was found that vortex flow pattern over the wing is dominated mainly by canard vertical position and in some cases, by merging of canard and wing vortices. In addition, the pressure loss induced by canard vortex on the wing surface moves the wing vortex toward the leading edge. In the mid canard configuration, canard and wing vortices merge at x/c greater than 0.5 and as a result of this phenomenon, abrupt pressure loss induces more stable vortex flow over the wing. It is also shown that canard plays a vital role in vortex break down over the wing.

  18. Improvement of the aerodynamic performance by wing flexibility and elytra–hind wing interaction of a beetle during forward flight

    Science.gov (United States)

    Le, Tuyen Quang; Truong, Tien Van; Park, Soo Hyung; Quang Truong, Tri; Ko, Jin Hwan; Park, Hoon Cheol; Byun, Doyoung

    2013-01-01

    In this work, the aerodynamic performance of beetle wing in free-forward flight was explored by a three-dimensional computational fluid dynamics (CFDs) simulation with measured wing kinematics. It is shown from the CFD results that twist and camber variation, which represent the wing flexibility, are most important when determining the aerodynamic performance. Twisting wing significantly increased the mean lift and camber variation enhanced the mean thrust while the required power was lower than the case when neither was considered. Thus, in a comparison of the power economy among rigid, twisting and flexible models, the flexible model showed the best performance. When the positive effect of wing interaction was added to that of wing flexibility, we found that the elytron created enough lift to support its weight, and the total lift (48.4 mN) generated from the simulation exceeded the gravity force of the beetle (47.5 mN) during forward flight. PMID:23740486

  19. Folding wings like a cockroach: a review of transverse wing folding ensign wasps (Hymenoptera: Evaniidae: Afrevania and Trissevania.

    Directory of Open Access Journals (Sweden)

    István Mikó

    Full Text Available We revise two relatively rare ensign wasp genera, whose species are restricted to Sub-Saharan Africa: Afrevania and Trissevania. Afrevania longipetiolata sp. nov., Trissevania heatherae sp. nov., T. hugoi sp. nov., T. mrimaensis sp. nov. and T. slideri sp. nov. are described, males and females of T. anemotis and Afrevania leroyi are redescribed, and an identification key for Trissevaniini is provided. We argue that Trissevania mrimaensis sp. nov. and T. heatherae sp. nov. populations are vulnerable, given their limited distributions and threats from mining activities in Kenya. We hypothesize that these taxa together comprise a monophyletic lineage, Trissevaniini, tr. nov., the members of which share the ability to fold their fore wings along two intersecting fold lines. Although wing folding of this type has been described for the hind wing of some insects four-plane wing folding of the fore wing has never been documented. The wing folding mechanism and the pattern of wing folds of Trissevaniini is shared only with some cockroach species (Blattodea. It is an interesting coincidence that all evaniids are predators of cockroach eggs. The major wing fold lines of Trissevaniini likely are not homologous to any known longitudinal anatomical structures on the wings of other Evaniidae. Members of the new tribe share the presence of a coupling mechanism between the fore wing and the mesosoma that is composed of a setal patch on the mesosoma and the retinaculum of the fore wing. While the setal patch is an evolutionary novelty, the retinaculum, which originally evolved to facilitate fore and hind wing coupling in Hymenoptera, exemplifies morphological exaptation. We also refine and clarify the Semantic Phenotype approach used in previous taxonomic revisions and explore the consequences of merging new with existing data. The way that semantic statements are formulated can evolve in parallel, alongside improvements to the ontologies themselves.

  20. Basal Complex and Basal Venation of Odonata Wings: Structural Diversity and Potential Role in the Wing Deformation.

    Directory of Open Access Journals (Sweden)

    H Rajabi

    Full Text Available Dragonflies and damselflies, belonging to the order Odonata, are known to be excellent fliers with versatile flight capabilities. The ability to fly over a wide range of speeds, high manoeuvrability and great agility are a few characteristics of their flight. The architecture of the wings and their structural elements have been found to play a major role in this regard. However, the precise influence of individual wing components on the flight performance of these insects remains unknown. The design of the wing basis (so called basal complex and the venation of this part are responsible for particular deformability and specific shape of the wing blade. However, the wing bases are rather different in representatives of different odonate groups. This presumably reflects the dimensions of the wings on one hand, and different flight characteristics on the other hand. In this article, we develop the first three-dimensional (3D finite element (FE models of the proximal part of the wings of typical representatives of five dragonflies and damselflies families. Using a combination of the basic material properties of insect cuticle, a linear elastic material model and a nonlinear geometric analysis, we simulate the mechanical behaviour of the wing bases. The results reveal that although both the basal venation and the basal complex influence the structural stiffness of the wings, it is only the latter which significantly affects their deformation patterns. The use of numerical simulations enabled us to address the role of various wing components such as the arculus, discoidal cell and triangle on the camber formation in flight. Our study further provides a detailed representation of the stress concentration in the models. The numerical analysis presented in this study is not only of importance for understanding structure-function relationship of insect wings, but also might help to improve the design of the wings for biomimetic micro-air vehicles (MAVs.

  1. Cantilever Wings for Modern Aircraft: Some Aspects of Cantilever Wing Construction with Special Reference to Weight and Torsional Stiffness

    Science.gov (United States)

    Stieger, H J

    1929-01-01

    In the foregoing remarks I have made an attempt to touch on some of the structural problems met with in cantilever wings, and dealt rather fully with a certain type of single-spar construction. The experimental test wing was a first attempt to demonstrate the principles of this departure from orthodox methods. The result was a wing both torsionally stiff and of light weight - lighter than a corresponding biplane construction.

  2. Fluctuations of offshore wind generation: Statistical modelling

    DEFF Research Database (Denmark)

    Pinson, Pierre; Christensen, Lasse E.A.; Madsen, Henrik

    2007-01-01

    The magnitude of power fluctuations at large offshore wind farms has a significant impact on the control and management strategies of their power output. If focusing on the minute scale, one observes successive periods with smaller and larger power fluctuations. It seems that different regimes yi...

  3. Dynamical interplay between fluctuations, electric fields and ...

    Indian Academy of Sciences (India)

    interplay between fluctuation in gradients, turbulent transport and radial electric fields has shown that these parameters ... electric fields and density fluctuations, ΓE¢B(t) = ˜n(t) ˜Eθ (t)/B. The poloidal electric field has been .... transport increases and the system performs a relaxation which tends to drive the plasma back to the ...

  4. Computer simulations of phospholipid - membrane thermodynamic fluctuations

    DEFF Research Database (Denmark)

    Pedersen, U.R.; Peters, Günther H.j.; Schröder, T.B.

    2008-01-01

    This paper reports all-atom computer simulations of five phospholipid membranes, DMPC, DPPC, DMPG, DMPS, and DMPSH, with a focus on the thermal equilibrium fluctuations of volume, energy, area, thickness, and order parameter. For the slow fluctuations at constant temperature and pressure (defined...

  5. temperature fluctuation inside inert atmosphere silos

    African Journals Online (AJOL)

    This research was conducted to study temperature fluctuation inside the inert atmosphere silos loaded with wheat, compare the temperature fluctuation across the top, middle and bottom part of the silo in relation to the ambient temperature. Temperature readings of the ambient and at the top, middle and bottom part of the ...

  6. Strategic exploitation of fluctuating asymmetry in male Endler’s guppy courtship displays is modulated by social environment

    Czech Academy of Sciences Publication Activity Database

    Řežucha, Radomil; Reichard, Martin

    2015-01-01

    Roč. 28, č. 2 (2015), s. 356-367 ISSN 1010-061X R&D Projects: GA ČR GBP505/12/G112 Institutional support: RVO:68081766 Keywords : behavioural laterality * experience * Poecilia wingei * sidedness * sigmoid display * social environment Subject RIV: EG - Zoology Impact factor: 2.747, year: 2015

  7. Quantification of upper limb kinetic asymmetries in front crawl swimming.

    Science.gov (United States)

    Morouço, Pedro G; Marinho, Daniel A; Fernandes, Ricardo J; Marques, Mário C

    2015-04-01

    This study aimed at quantifying upper limb kinetic asymmetries in maximal front crawl swimming and to examine if these asymmetries would affect the contribution of force exertion to swimming performance. Eighteen high level male swimmers with unilateral breathing patterns and sprint or middle distance specialists, volunteered as participants. A load-cell was used to quantify the forces exerted in water by completing a 30s maximal front crawl tethered swimming test and a maximal 50 m free swimming was considered as a performance criterion. Individual force-time curves were obtained to calculate the mean and maximum forces per cycle, for each upper limb. Following, symmetry index was estimated and breathing laterality identified by questionnaire. Lastly, the pattern of asymmetries along the test was estimated for each upper limb using linear regression of peak forces per cycle. Asymmetrical force exertion was observed in the majority of the swimmers (66.7%), with a total correspondence of breathing laterality opposite to the side of the force asymmetry. Forces exerted by the dominant upper limb presented a higher decrease than from the non-dominant. Very strong associations were found between exerted forces and swimming performance, when controlling the isolated effect of symmetry index. Results point that force asymmetries occur in the majority of the swimmers, and that these asymmetries are most evident in the first cycles of a maximum bout. Symmetry index stood up as an influencing factor on the contribution of tethered forces over swimming performance. Thus, to some extent, a certain degree of asymmetry is not critical for short swimming performance. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Karyotipic asymmetry of both wild and cultivated species of Pennisetum

    Directory of Open Access Journals (Sweden)

    Vânia Helena Techio

    2010-01-01

    Full Text Available This study aimed the establishment of the relation between karyotipic asymmetry values obtained for different accessions of both wild and cultivated species of Pennisetum from Germplasm Bank of Embrapa Gado de Leite/Juiz de Fora-Minas Gerais State, Brazil. Conventional cell cycle synchronization protocols and Feulgen staining method were used to obtain metaphases plates. The wild-type accessions corresponded to the species P. setosum (2n=6x=54, P. nervosum (2n=4x=36, and P. orientale (2n=4x=36, and the cultivated to P. purpureum (2n=4x=28 and P. glaucum (2n=2x=14. No significant difference was found for the total length of chromosomes (p>0.05 among the species. The analysis of intra-chromosomal asymmetry (A1 and inter-chromosomal asymmetry (A2 has shown that P. setosum has a tendency to chromosome asymmetry. P. nervosum, P. orientale, and P. purpureum have presented an intermediary level of asymmetry and P. glaucum, low asymmetry. Considering Stebbins criteria, the karyotype of P. glaucum and those from the three wild species fitted into the category 1A-symmetrical. With regard to P. purpureum, karyotypes of the accessions BAGs 54, 65 and 91 fitted into the category 2B and the other two genotypes (BAGs 63 and 75 fitted into the 1A. Comparison between the karyotype classification according to the inter- and intra-chromosomal asymmetry and Stebbins methodologies revealed that this last one alone was not able to detect small variations between karyotypes of the taxa closely related.

  9. Demonstration of an in situ morphing hyperelliptical cambered span wing mechanism

    International Nuclear Information System (INIS)

    Manzo, Justin; Garcia, Ephrahim

    2010-01-01

    Research on efficient shore bird morphology inspired the hyperelliptical cambered span (HECS) wing, a crescent-shaped, aft-swept wing with vertically oriented wingtips. The wing reduces vorticity-induced circulation loss and outperforms an elliptical baseline when planar. Designed initially as a rigid wing, the HECS wing makes use of morphing to transition from a planar to a furled configuration, similar to that of a continuously curved winglet, in flight. A morphing wing concept mechanism is presented, employing shape memory alloy actuators to create a discretized curvature approximation. The aerodynamics for continuous wing shapes is validated quasi-statically through wind tunnel testing, showing enhanced planar HECS wing lift-to-drag performance over an elliptical wing, with the furled HECS wing showing minimal enhancements beyond this point. Wind tunnel tests of the active morphing wing prove the mechanism capable of overcoming realistic loading, while further testing may be required to establish aerodynamic merits of the HECS wing morphing maneuver

  10. Coupled Quantum Fluctuations and Quantum Annealing

    Science.gov (United States)

    Hormozi, Layla; Kerman, Jamie

    We study the relative effectiveness of coupled quantum fluctuations, compared to single spin fluctuations, in the performance of quantum annealing. We focus on problem Hamiltonians resembling the the Sherrington-Kirkpatrick model of Ising spin glass and compare the effectiveness of different types of fluctuations by numerically calculating the relative success probabilities and residual energies in fully-connected spin systems. We find that for a small class of instances coupled fluctuations can provide improvement over single spin fluctuations and analyze the properties of the corresponding class. Disclaimer: This research was funded by ODNI, IARPA via MIT Lincoln Laboratory under Air Force Contract No. FA8721-05-C-0002. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of ODNI, IARPA, or the US Government.

  11. Multiplicity Distributions and Charged-neutral Fluctuations

    CERN Document Server

    Nayak, Tapan K.; Agnihotri, A.; Ahammed, Z.; Angelis, A.L.S.; Antonenko, V.; Arefev, V.; Astakhov, V.; Avdeitchikov, V.; Awes, T.C.; Baba, P.V.K.S.; Badyal, S.K.; Baldine, A.; Barabach, L.; Barlag, C.; Bathe, S.; Batiounia, B.; Bernier, T.; Bhalla, K.B.; Bhatia, V.S.; Blume, C.; Bock, R.; Bohne, E.M.; Bucher, D.; Buijs, A.; Buis, E.J.; Busching, H.; Carlen, L.; Chalyshev, V.; Chattopadhyay, S.; Chenawi, K.E.; Cherbatchev, R.; Chujo, T.; Claussen, A.; Das, A.C.; Decowski, M.P.; Djordjadze, V.; Donni, P.; Doubovik, I.; Dubey, A.K.; Dutta Majumda, M.R.; Eliseev, S.; Enosawa, K.; Feldmann, H.; Foka, P.; Fokin, S.; Frolov, V.; Ganti, M.S.; Garpman, S.; Gavrishchuk, O.; Geurts, F.J.M.; Ghosh, T.K.; Glasow, R.; Gupta, S.K.; Guskov, B.; Gustafsson, H.A.; Gutbrod, H.H.; Higuchi, R.; Hrivnacova, I.; Ippolitov, M.; Kalechofsky, H.; Kamermans, R.; Kampert, K.H.; Karadjev, K.; Karpio, K.; Kato, S.; Kees, S.; Kim, H.; Kolb, B.W.; Kosarev, I.; Koutcheryaev, I.; Kugler, A.; Kulinich, P.; Kumar, V.; Kurata, M.; Kurita, K.; Kuzmin, N.; Langbein, I.; Lebedev, A.; Lee, Y.Y.; Lohner, H.; Mahapatra, D.P.; Manko, V.; Martin, M.; Maximov, A.; Mehdiyev, Rashid R.; Mgebrichvili, G.; Miake, Y.; Mikhalev, D.; Mishra, G.C.; Miyamoto, Y.; Mohanty, B.; Morrison, Douglas R.O.; Mukhopadhyay, D.S.; Myalkovski, V.; Naef, H.; Nandi, B.K.; Nayak, S.K.; Nayak, T.K.; Neumaier, S.; Nianine, A.; Nikitine, V.; Nikolaev, S.; Nishimura, S.; Nomokov, P.; Nystrand, J.; Obenshain, F.E.; Oskarsson, A.; Otterlund, I.; Pachr, M.; Parfenov, A.; Pavliouk, S.; Peitzmann, T.; Petracek, V.; Plasil, F.; Purschke, M.L.; Raeven, B.; Rak, J.; Raniwala, R.; Raniwala, S.; Ramamurthy, V.S.; Rao, N.K.; Retiere, F.; Reygers, K.; Roland, G.; Rosselet, L.; Roufanov, I.; Rubio, J.M.; Sambyal, S.S.; Santo, R.; Sato, S.; Schlagheck, H.; Schmidt, H.R.; Shabratova, G.; Sibiriak, I.; Siemiarczuk, T.; Sinha, B.C.; Slavine, N.; Soderstrom, K.; Solomey, N.; Sood, G.; Sorensen, S.P.; Stankus, P.; Stefanek, G.; Steinberg, P.; Stenlund, E.; Stuken, D.; Sumbera, M.; Svensson, T.; Trivedi, M.D.; Tsvetkov, A.; Twenhofel, C.; Tykarski, L.; Urbahn, J.; van Eijndhoven, N.; van Heeringen, W.H.; van Nieuwenhuizen, G.J.; Vinogradov, A.; Viyogi, Y.P.; Vodopianov, A.S.; Voros, S.; Vos, M.A.; Wyslouch, B.; Yagi, K.; Yokota, Y.; Young, G.R.; Nayak, Tapan K.

    2001-01-01

    Results from the multiplicity distributions of inclusive photons and charged particles, scaling of particle multiplicities, event-by-event multiplicity fluctuations, and charged-neutral fluctuations in 158$\\cdot A$ GeV Pb+Pb collisions are presented and discussed. A scaling of charged particle multiplicity as $N_{part}^{1.07\\pm 0.05}$ and photons as $N_{part}^{1.12\\pm 0.03}$ have been observed, indicating violation of naive wounded nucleon model. The analysis of localized charged-neutral fluctuation indicates a model-independent demonstration of non-statistical fluctuations in both charged particles and photons in limited azimuthal regions. However, no correlated charged-neutral fluctuations are observed.

  12. Biomechanics of smart wings in a bat robot: morphing wings using SMA actuators

    International Nuclear Information System (INIS)

    Colorado, J; Barrientos, A; Rossi, C; Breuer, K S

    2012-01-01

    This paper presents the design of a bat-like micro aerial vehicle with actuated morphing wings. NiTi shape memory alloys (SMAs) acting as artificial biceps and triceps muscles are used for mimicking the morphing wing mechanism of the bat flight apparatus. Our objective is twofold. Firstly, we have implemented a control architecture that allows an accurate and fast SMA actuation. This control makes use of the electrical resistance measurements of SMAs to adjust morphing wing motions. Secondly, the feasibility of using SMA actuation technology is evaluated for the application at hand. To this purpose, experiments are conducted to analyze the control performance in terms of nominal and overloaded operation modes of the SMAs. This analysis includes: (i) inertial forces regarding the stretchable wing membrane and aerodynamic loads, and (ii) uncertainties due to impact of airflow conditions over the resistance–motion relationship of SMAs. With the proposed control, morphing actuation speed can be increased up to 2.5 Hz, being sufficient to generate lift forces at a cruising speed of 5 m s −1 . (paper)

  13. Biomechanics of smart wings in a bat robot: morphing wings using SMA actuators.

    Science.gov (United States)

    Colorado, J; Barrientos, A; Rossi, C; Bahlman, J W; Breuer, K S

    2012-09-01

    This paper presents the design of a bat-like micro aerial vehicle with actuated morphing wings. NiTi shape memory alloys (SMAs) acting as artificial biceps and triceps muscles are used for mimicking the morphing wing mechanism of the bat flight apparatus. Our objective is twofold. Firstly, we have implemented a control architecture that allows an accurate and fast SMA actuation. This control makes use of the electrical resistance measurements of SMAs to adjust morphing wing motions. Secondly, the feasibility of using SMA actuation technology is evaluated for the application at hand. To this purpose, experiments are conducted to analyze the control performance in terms of nominal and overloaded operation modes of the SMAs. This analysis includes: (i) inertial forces regarding the stretchable wing membrane and aerodynamic loads, and (ii) uncertainties due to impact of airflow conditions over the resistance-motion relationship of SMAs. With the proposed control, morphing actuation speed can be increased up to 2.5 Hz, being sufficient to generate lift forces at a cruising speed of 5 m s(-1).

  14. A parametric wing design study for a modern laminar flow wing

    Science.gov (United States)

    Koegler, J. A., Jr.

    1979-01-01

    The results of a parametric wing design study using a modern laminar flow airfoil designed to exhibit desirable stall characteristics while maintaining high cruise performance are presented. It was found that little is sacrificed in cruise performance when satisfying the stall margin requirements if a taper ratio of 0.65 or greater is used.

  15. SUPERDENSE MASSIVE GALAXIES IN WINGS LOCAL CLUSTERS

    International Nuclear Information System (INIS)

    Valentinuzzi, T.; D'Onofrio, M.; Fritz, J.; Poggianti, B. M.; Bettoni, D.; Fasano, G.; Moretti, A.; Omizzolo, A.; Varela, J.; Cava, A.; Couch, W. J.; Dressler, A.; Moles, M.; Kjaergaard, P.; Vanzella, E.

    2010-01-01

    Massive quiescent galaxies at z > 1 have been found to have small physical sizes, and hence to be superdense. Several mechanisms, including minor mergers, have been proposed for increasing galaxy sizes from high- to low-z. We search for superdense massive galaxies in the WIde-field Nearby Galaxy-cluster Survey (WINGS) of X-ray selected galaxy clusters at 0.04 10 M sun , are mostly S0 galaxies, have a median effective radius (R e ) = 1.61 ± 0.29 kpc, a median Sersic index (n) = 3.0 ± 0.6, and very old stellar populations with a median mass-weighted age of 12.1 ± 1.3 Gyr. We calculate a number density of 2.9 x 10 -2 Mpc -3 for superdense galaxies in local clusters, and a hard lower limit of 1.3 x 10 -5 Mpc -3 in the whole comoving volume between z = 0.04 and z = 0.07. We find a relation between mass, effective radius, and luminosity-weighted age in our cluster galaxies, which can mimic the claimed evolution of the radius with redshift, if not properly taken into account. We compare our data with spectroscopic high-z surveys and find that-when stellar masses are considered-there is consistency with the local WINGS galaxy sizes out to z ∼ 2, while a discrepancy of a factor of 3 exists with the only spectroscopic z > 2 study. In contrast, there is strong evidence for a large evolution in radius for the most massive galaxies with M * > 4 x 10 11 M sun compared to similarly massive galaxies in WINGS, i.e., the brightest cluster galaxies.

  16. Stability and fluctuations in black hole thermodynamics

    International Nuclear Information System (INIS)

    Ruppeiner, George

    2007-01-01

    I examine thermodynamic fluctuations for a Kerr-Newman black hole in an extensive, infinite environment. This problem is not strictly solvable because full equilibrium with such an environment cannot be achieved by any black hole with mass M, angular momentum J, and charge Q. However, if we consider one (or two) of M, J, or Q to vary so slowly compared with the others that we can regard it as fixed, instances of stability occur, and thermodynamic fluctuation theory could plausibly apply. I examine seven cases with one, two, or three independent fluctuating variables. No knowledge about the thermodynamic behavior of the environment is needed. The thermodynamics of the black hole is sufficient. Let the fluctuation moment for a thermodynamic quantity X be √( 2 >). Fluctuations at fixed M are stable for all thermodynamic states, including that of a nonrotating and uncharged environment, corresponding to average values J=Q=0. Here, the fluctuation moments for J and Q take on maximum values. That for J is proportional to M. For the Planck mass it is 0.3990(ℎ/2π). That for Q is 3.301e, independent of M. In all cases, fluctuation moments for M, J, and Q go to zero at the limit of the physical regime, where the temperature goes to zero. With M fluctuating there are no stable cases for average J=Q=0. But, there are transitions to stability marked by infinite fluctuations. For purely M fluctuations, this coincides with a curve which Davies identified as a phase transition

  17. Effects of boundary layer forcing on wing-tip vortices

    Science.gov (United States)

    Shaw-Ward, Samantha

    The nature of turbulence within wing-tip vortices has been a topic of research for decades, yet accurate measurements of Reynolds stresses within the core are inherently difficult due to the bulk motion wandering caused by initial and boundary conditions in wind tunnels. As a result, characterization of a vortex as laminar or turbulent is inconclusive and highly contradicting. This research uses several experimental techniques to study the effects of broadband turbulence, introduced within the wing boundary layer, on the development of wing-tip vortices. Two rectangular wings with a NACA 0012 profile were fabricated for the use of this research. One wing had a smooth finish and the other rough, introduced by P80 grade sandpaper. Force balance measurements showed a small reduction in wing performance due to surface roughness for both 2D and 3D configurations, although stall characteristics remained relatively unchanged. Seven-hole probes were purpose-built and used to assess the mean velocity profiles of the vortices five chord lengths downstream of the wing at multiple angles of attack. Above an incidence of 4 degrees, the vortices were nearly axisymmetric, and the wing roughness reduced both velocity gradients and peak velocity magnitudes within the vortex. Laser Doppler velocimetry was used to further assess the time-resolved vortex at an incidence of 5 degrees. Evidence of wake shedding frequencies and wing shear layer instabilities at higher frequencies were seen in power spectra within the vortex. Unlike the introduction of freestream turbulence, wing surface roughness did not appear to increase wandering amplitude. A new method for removing the effects of vortex wandering is proposed with the use of carefully selected high-pass filters. The filtered data revealed that the Reynolds stress profiles of the vortex produced by the smooth and rough wing were similar in shape, with a peak occurring away from the vortex centre but inside of the core. Single hot

  18. Folding in and out: passive morphing in flapping wings.

    Science.gov (United States)

    Stowers, Amanda K; Lentink, David

    2015-03-25

    We present a new mechanism for passive wing morphing of flapping wings inspired by bat and bird wing morphology. The mechanism consists of an unactuated hand wing connected to the arm wing with a wrist joint. Flapping motion generates centrifugal accelerations in the hand wing, forcing it to unfold passively. Using a robotic model in hover, we made kinematic measurements of unfolding kinematics as functions of the non-dimensional wingspan fold ratio (2-2.5) and flapping frequency (5-17 Hz) using stereo high-speed cameras. We find that the wings unfold passively within one to two flaps and remain unfolded with only small amplitude oscillations. To better understand the passive dynamics, we constructed a computer model of the unfolding process based on rigid body dynamics, contact models, and aerodynamic correlations. This model predicts the measured passive unfolding within about one flap and shows that unfolding is driven by centrifugal acceleration induced by flapping. The simulations also predict that relative unfolding time only weakly depends on flapping frequency and can be reduced to less than half a wingbeat by increasing flapping amplitude. Subsequent dimensional analysis shows that the time required to unfold passively is of the same order of magnitude as the flapping period. This suggests that centrifugal acceleration can drive passive unfolding within approximately one wingbeat in small and large wings. Finally, we show experimentally that passive unfolding wings can withstand impact with a branch, by first folding and then unfolding passively. This mechanism enables flapping robots to squeeze through clutter without sophisticated control. Passive unfolding also provides a new avenue in morphing wing design that makes future flapping morphing wings possibly more energy efficient and light-weight. Simultaneously these results point to possible inertia driven, and therefore metabolically efficient, control strategies in bats and birds to morph or recover

  19. Video change detection for fixed wing UAVs

    Science.gov (United States)

    Bartelsen, Jan; Müller, Thomas; Ring, Jochen; Mück, Klaus; Brüstle, Stefan; Erdnüß, Bastian; Lutz, Bastian; Herbst, Theresa

    2017-10-01

    In this paper we proceed the work of Bartelsen et al.1 We present the draft of a process chain for an image based change detection which is designed for videos acquired by fixed wing unmanned aerial vehicles (UAVs). From our point of view, automatic video change detection for aerial images can be useful to recognize functional activities which are typically caused by the deployment of improvised explosive devices (IEDs), e.g. excavations, skid marks, footprints, left-behind tooling equipment, and marker stones. Furthermore, in case of natural disasters, like flooding, imminent danger can be recognized quickly. Due to the necessary flight range, we concentrate on fixed wing UAVs. Automatic change detection can be reduced to a comparatively simple photogrammetric problem when the perspective change between the "before" and "after" image sets is kept as small as possible. Therefore, the aerial image acquisition demands a mission planning with a clear purpose including flight path and sensor configuration. While the latter can be enabled simply by a fixed and meaningful adjustment of the camera, ensuring a small perspective change for "before" and "after" videos acquired by fixed wing UAVs is a challenging problem. Concerning this matter, we have performed tests with an advanced commercial off the shelf (COTS) system which comprises a differential GPS and autopilot system estimating the repetition accuracy of its trajectory. Although several similar approaches have been presented,23 as far as we are able to judge, the limits for this important issue are not estimated so far. Furthermore, we design a process chain to enable the practical utilization of video change detection. It consists of a front-end of a database to handle large amounts of video data, an image processing and change detection implementation, and the visualization of the results. We apply our process chain on the real video data acquired by the advanced COTS fixed wing UAV and synthetic data. For the

  20. How the pterosaur got its wings.

    Science.gov (United States)

    Tokita, Masayoshi

    2015-11-01

    Throughout the evolutionary history of life, only three vertebrate lineages took to the air by acquiring a body plan suitable for powered flight: birds, bats, and pterosaurs. Because pterosaurs were the earliest vertebrate lineage capable of powered flight and included the largest volant animal in the history of the earth, understanding how they evolved their flight apparatus, the wing, is an important issue in evolutionary biology. Herein, I speculate on the potential basis of pterosaur wing evolution using recent advances in the developmental biology of flying and non-flying vertebrates. The most significant morphological features of pterosaur wings are: (i) a disproportionately elongated fourth finger, and (ii) a wing membrane called the brachiopatagium, which stretches from the posterior surface of the arm and elongated fourth finger to the anterior surface of the leg. At limb-forming stages of pterosaur embryos, the zone of polarizing activity (ZPA) cells, from which the fourth finger eventually differentiates, could up-regulate, restrict, and prolong expression of 5'-located Homeobox D (Hoxd) genes (e.g. Hoxd11, Hoxd12, and Hoxd13) around the ZPA through pterosaur-specific exploitation of sonic hedgehog (SHH) signalling. 5'Hoxd genes could then influence downstream bone morphogenetic protein (BMP) signalling to facilitate chondrocyte proliferation in long bones. Potential expression of Fgf10 and Tbx3 in the primordium of the brachiopatagium formed posterior to the forelimb bud might also facilitate elongation of the phalanges of the fourth finger. To establish the flight-adapted musculoskeletal morphology shared by all volant vertebrates, pterosaurs probably underwent regulatory changes in the expression of genes controlling forelimb and pectoral girdle musculoskeletal development (e.g. Tbx5), as well as certain changes in the mode of cell-cell interactions between muscular and connective tissues in the early phase of their evolution. Developmental data now

  1. How wing kinematics affect power requirements and aerodynamic force production in a robotic bat wing

    International Nuclear Information System (INIS)

    Bahlman, Joseph W; Swartz, Sharon M; Breuer, Kenneth S

    2014-01-01

    Bats display a wide variety of behaviors that require different amounts of aerodynamic force. To control and modulate aerodynamic force, bats change wing kinematics, which, in turn, may change the power required for wing motion. There are many kinematic mechanisms that bats, and other flapping animals, can use to increase aerodynamic force, e.g. increasing wingbeat frequency or amplitude. However, we do not know if there is a difference in energetic cost between these different kinematic mechanisms. To assess the relationship between mechanical power input and aerodynamic force output across different isolated kinematic parameters, we programmed a robotic bat wing to flap over a range of kinematic parameters and measured aerodynamic force and mechanical power. We systematically varied five kinematic parameters: wingbeat frequency, wingbeat amplitude, stroke plane angle, downstroke ratio, and wing folding. Kinematic values were based on observed values from free flying Cynopterus brachyotis, the species on which the robot was based. We describe how lift, thrust, and power change with increases in each kinematic variable. We compare the power costs associated with generating additional force through the four kinematic mechanisms controlled at the shoulder, and show that all four mechanisms require approximately the same power to generate a given force. This result suggests that no single parameter offers an energetic advantage over the others. Finally, we show that retracting the wing during upstroke reduces power requirements for flapping and increases net lift production, but decreases net thrust production. These results compare well with studies performed on C. brachyotis, offering insight into natural flight kinematics. (paper)

  2. Hemispheric asymmetry and theory of mind: is there an association?

    Science.gov (United States)

    Herzig, Daniela A; Sullivan, Sarah; Evans, Jonathan; Corcoran, Rhiannon; Mohr, Christine

    2012-01-01

    In autism and schizophrenia attenuated/atypical functional hemispheric asymmetry and theory of mind impairments have been reported, suggesting common underlying neuroscientific correlates. We here investigated whether impaired theory of mind performance is associated with attenuated/atypical hemispheric asymmetry. An association may explain the co-occurrence of both dysfunctions in psychiatric populations. Healthy participants (n=129) performed a left hemisphere (lateralised lexical decision task) and right hemisphere (lateralised face decision task) dominant task as well as a visual cartoon task to assess theory of mind performance. Linear regression analyses revealed inconsistent associations between theory of mind performance and functional hemisphere asymmetry: enhanced theory of mind performance was only associated with (1) faster right hemisphere language processing, and (2) reduced right hemisphere dominance for face processing (men only). The majority of non-significant findings suggest that theory of mind and functional hemispheric asymmetry are unrelated. Instead of "overinterpreting" the two significant results, discrepancies in the previous literature relating to the problem of the theory of mind concept, the variety of tasks, and the lack of normative data are discussed. We also suggest how future studies could explore a possible link between hemispheric asymmetry and theory of mind.

  3. [Perception of asymmetry smile: Attempt to evaluation through Photoshop].

    Science.gov (United States)

    Diakite, C; Diep, D; Labbe, D

    2016-04-01

    In the labial palliative surgery of facial paralysis, it can persist asymmetry smile. Evaluate the impact of an augmentation or reduction of the commissural course on the perception of a smile anomaly, and determine from which asymmetry threshold, the smile is estimated unsightly. We took a picture of two people with a smile not forced; including one with a "cuspid smile", and the another one with a "Mona Lisa" smile. The pictures obtained were modified by the Photoshop software, to simulate an asymmetry labial smile. The changes were related to the move of the left labial commissure, the left nasolabial furrow, and the left cheek using under-correction and overcorrection, every 4 mm. Three pictures with under-correction and four pictures with over-correction were obtained. These smiles were shown to three groups of five people, which included doctors in smile specialties, doctors in other specialties, and non-doctors. Participants were then asked to indicate on which of the pictures, the smile seemed abnormal. Between -8 mm under-correction, and +8 mm over-correction, the asymmetry of the commissural course does not hinder the perception of smile. In the labial palliative surgery of facial paralysis, in the case of persistent asymmetry, there is a tolerance in the perception of "normality" of smile concerning the amplitude of the commissural course going up to 8 mm of asymmetric with under-correction or over-correction. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  4. Frontal EEG Asymmetry of Mood: A Mini-Review

    Directory of Open Access Journals (Sweden)

    Massimiliano Palmiero

    2017-11-01

    Full Text Available The present mini-review was aimed at exploring the frontal EEG asymmetry of mood. With respect to emotion, interpreted as a discrete affective process, mood is more controllable, more nebulous, and more related to mind/cognition; in addition, causes are less well-defined than those eliciting emotion. Therefore, firstly, the rational for the distinction between emotion and mood was provided. Then, the main frontal EEG asymmetry models were presented, such as the motivational approach/withdrawal, valence/arousal, capability, and inhibition asymmetric models. Afterward, the frontal EEG asymmetry of mood was investigated following three research lines, that is considering studies involving different mood induction procedures, dispositional mood (positive and negative affect, and mood alterations in both healthy and clinical populations. In general, results were found to be contradictory, no model is unequivocally supported regardless the research line considered. Different methodological issues were raised, such as: the composition of samples used across studies, in particular, gender and age were found to be critical variables that should be better addressed in future studies; the importance of third variables that might mediate the relationship between frontal EEG asymmetries and mood, for example bodily states and hormonal responses; the role of cognition, namely the interplay between mood and executive functions. In light of these issues, future research directions were proposed. Amongst others, the need to explore the neural connectivity that underpins EEG asymmetries, and the need to include both positive and negative mood conditions in the experimental designs have been highlighted.

  5. Prediction of Gap Asymmetry in Differential Micro Accelerometers

    Directory of Open Access Journals (Sweden)

    Xiaoping He

    2012-05-01

    Full Text Available Gap asymmetry in differential capacitors is the primary source of the zero bias output of force-balanced micro accelerometers. It is also used to evaluate the applicability of differential structures in MEMS manufacturing. Therefore, determining the asymmetry level has considerable significance for the design of MEMS devices. This paper proposes an experimental-theoretical method for predicting gap asymmetry in differential sensing capacitors of micro accelerometers. The method involves three processes: first, bi-directional measurement, which can sharply reduce the influence of the feedback circuit on bias output, is proposed. Experiments are then carried out on a centrifuge to obtain the input and output data of an accelerometer. Second, the analytical input-output relationship of the accelerometer with gap asymmetry and circuit error is theoretically derived. Finally, the prediction methodology combines the measurement results and analytical derivation to identify the asymmetric error of 30 accelerometers fabricated by DRIE. Results indicate that the level of asymmetry induced by fabrication uncertainty is about ±5 × 10−2, and that the absolute error is about ±0.2 µm under a 4 µm gap.

  6. Application of Low-Cost Fixed-Wing UAV for Inland Lakes Shoreline Investigation

    Science.gov (United States)

    Templin, Tomasz; Popielarczyk, Dariusz; Kosecki, Rafał

    2017-10-01

    One of the most important factors that influences the performance of geomorphologic parameters on urban lakes is the water level. It fluctuates periodically, causing shoreline changes. It is especially significant for typical environmental studies like bathymetric surveys, morphometric parameters calculation, sediment depth changes, thermal structure, water quality monitoring, etc. In most reservoirs, it can be obtained from digitized historical maps or plans or directly measured using the instruments such as: geodetic total station, GNSS receivers, UAV with different sensors, satellite and aerial photos, terrestrial and airborne light detection and ranging, or others. Today one of the most popular measuring platforms, increasingly applied in many applications is UAV. Unmanned aerial system can be a cheap, easy to use, on-demand technology for gathering remote sensing data. Our study presents a reliable methodology for shallow lake shoreline investigation with the use of a low-cost fixed-wing UAV system. The research was implemented on a small, eutrophic urban inland reservoir located in the northern part of Poland—Lake Suskie. The geodetic TS, and RTK/GNSS measurements, hydroacoustic soundings and experimental aerial mapping were conducted by the authors in 2012-2015. The article specifically describes the UAV system used for experimental measurements, the obtained results and the accuracy analysis. Final conclusions demonstrate that even a low-cost fixed-wing UAV can provide an excellent tool for accurately surveying a shallow lake shoreline and generate valuable geoinformation data collected definitely faster than when traditional geodetic methods are employed.

  7. Collective modes and spin fluctuations for spin-triplet superconducting state in Sr2RuO4

    International Nuclear Information System (INIS)

    Tewordt, L.

    1999-01-01

    First the authors calculate the collective order parameter modes for the most promising candidates of spin-triplet p-wave pairing states in the layered perovskite structure of Sr 2 RuO 4 . The pairing interaction and accordingly the equations for the order parameter fluctuations are decomposed in terms of spin-triplet pairing states corresponding to the irreducible representations of the point group D 4h . Asymmetric pairing interaction and spin-orbit coupling give rise to finite frequencies of the original Goldstone modes corresponding to broken rotational symmetry. These fluctuations of the rvec d-vector within the basal plane can be excited by external fields lying in the plane and coupling to spin density. The fluctuations of the amplitude of the rvec d-vector perpendicular to the basal plane have frequency ω = 2Δ 0 for the state without nodes and ω = √3 Δ 0 for the state with nodes (Δ 0 is the amplitude of the gap). These modes couple to charge density by electron-hole asymmetry at the Fermi surface. In the second part the author develops the self-consistent FLEX (fluctuation exchange) approximation for spin-triplet pairing mediated by exchange of spin fluctuations. At T c the pairing interaction is only one third of that for singlet-pairing. Below T c the feed-back effect stabilizes the spin-triplet state with rvec d-vector perpendicular to the basal plane

  8. Morphing Wing Design with an Innovative Three-Dimensional Warping Actuation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced wing configurations where traditional control surfaces are replaced by dynamically controlled distribution of wing twist and/or camber can provide...

  9. Variable Geometry Aircraft Wing Supported by Struts And/Or Trusses

    Science.gov (United States)

    Melton, John E. (Inventor); Dudley, Michael R. (Inventor)

    2016-01-01

    The present invention provides an aircraft having variable airframe geometry for accommodating efficient flight. The aircraft includes an elongated fuselage, an oblique wing pivotally connected with said fuselage, a wing pivoting mechanism connected with said oblique wing and said fuselage, and a brace operably connected between said oblique wing and said fuselage. The present invention also provides an aircraft having an elongated fuselage, an oblique wing pivotally connected with said fuselage, a wing pivoting mechanism connected with said oblique wing and said fuselage, a propulsion system pivotally connected with said oblique wing, and a brace operably connected between said propulsion system and said fuselage.

  10. Frequency of dentofacial asymmetries: a cross-sectional study on orthodontic patients.

    Science.gov (United States)

    Bhateja, Nita Kumari; Fida, Mubassar; Shaikh, Attiya

    2014-01-01

    Correction of orthodontic asymmetries is crucial to achieve functional occlusion, aesthetics and stability of post orthodontic treatment results. To date valid frequency data of dentofacial asymmetries in Pakistani orthodontic patients do not exist to document orthodontic treatment need. The objectives of this study were to determine frequency of dento-facial asymmetries, severity of dental asymmetries and to determine difference in frequency of dentofacial asymmetries in mixed and permanent dentition. The sample of this cross-sectional study comprised of 280 patients (177 females and 103 males) with no history of previous orthodontic treatment having no craniofacial anomalies. Dento-facial asymmetries were assessed from pre-treatment records of patients. Descriptive statistics were used to determine frequency of dentofacial asymmetries and severity of dental asymmetries. Chi-square test was used to determine difference in frequency of dentofacial asymmetries in mixed and permanent dentition. Seventy eight percent (219) of patients had noncoincident midlines, 67.5% (189) had mandibular midline asymmetry, 43.2% (122) had molar asymmetry, 15.7% (44) had mandibular arch asymmetry, 14.3% (40) had maxillary midline asymmetry, 13.6% (38) had maxillary arch asymmetry, 6.1% (17) had nose deviation, and 12.1% (34) had facial asymmetry and chin deviation. In most patients dental midlines were deviated from one another and from facial midline by ¼ lower incisor widths, while molar asymmetry was found in most patients by ¼ cusp width. Mandibular arch asymmetry was more frequent in permanent than mixed dentition (p = 0.054). Non-coincident dental midline is most commonly seen. Nose deviation is least commonly observed. Mandibular arch asymmetry is more frequent in permanent than mixed dentition.

  11. Numerical simulation of X-wing type biplane flapping wings in 3D using the immersed boundary method

    International Nuclear Information System (INIS)

    Tay, W B; Van Oudheusden, B W; Bijl, H

    2014-01-01

    The numerical simulation of an insect-sized ‘X-wing’ type biplane flapping wing configuration is performed in 3D using an immersed boundary method solver at Reynolds numbers equal to 1000 (1 k) and 5 k, based on the wing's root chord length. This X-wing type flapping configuration draws its inspiration from Delfly, a bio-inspired ornithopter MAV which has two pairs of wings flapping in anti-phase in a biplane configuration. The objective of the present investigation is to assess the aerodynamic performance when the original Delfly flapping wing micro-aerial vehicle (FMAV) is reduced to the size of an insect. Results show that the X-wing configuration gives more than twice the average thrust compared with only flapping the upper pair of wings of the X-wing. However, the X-wing's average thrust is only 40% that of the upper wing flapping at twice the stroke angle. Despite this, the increased stability which results from the smaller lift and moment variation of the X-wing configuration makes it more suited for sharp image capture and recognition. These advantages make the X-wing configuration an attractive alternative design for insect-sized FMAVS compared to the single wing configuration. In the Reynolds number comparison, the vorticity iso-surface plot at a Reynolds number of 5 k revealed smaller, finer vortical structures compared to the simulation at 1 k, due to vortices’ breakup. In comparison, the force output difference is much smaller between Re = 1 k and 5 k. Increasing the body inclination angle generates a uniform leading edge vortex instead of a conical one along the wingspan, giving higher lift. Understanding the force variation as the body inclination angle increases will allow FMAV designers to optimize the thrust and lift ratio for higher efficiency under different operational requirements. Lastly, increasing the spanwise flexibility of the wings increases the thrust slightly but decreases the efficiency. The thrust result is similar

  12. Wing design for light transport aircraft with improved fuel economy

    Energy Technology Data Exchange (ETDEWEB)

    Welte, D.; Birrenbach, R.; Haberland, W.

    An advanced technology wing has been designed for a light utility and commuter service aircraft with the requirements for economy, safety and flexibility. Trade-off studies give optimum area and aspect-ratio of the wing. A new airfoil was developed to fulfill the performance requirements. Wing planform and twist were chosen to give high maximum lift, low drag and good stall characteristics. Preset ailerons were optimized for wheel forces and lateral control. The applied aerodynamic methods, including two- and three-dimensional wind tunnel tests are shown. Various structural configurations of the wing and various flap systems are evaluated. The cantilever tapered wing and a Fowler-flap with a two-lever mechanism were found to be the most economic ones. The wing was constructed and flight-tested with a modified Dornier Do 28 Skyservant as a test bed. The new wing is being applied to a family of light transport aircraft. Finally, aircraft with the new wing are compared performancewise with contemporary aircraft.

  13. Design and Testing of Aeroelastically Tailored Wings Under Maneuver Loading

    NARCIS (Netherlands)

    Werter, N.P.M.; Sodja, J.; De Breuker, R.

    2016-01-01

    The goal of the present paper is to provide experimental validation data for the aeroelastic analysis of composite aeroelastically tailored wings with a closed-cell cross-sectional structure. Several rectangular wings with differ- ent skin thicknesses and composite layups are designed in order to

  14. Optimisation of the Sekwa blended-wing-Body research UAV

    CSIR Research Space (South Africa)

    Broughton, BA

    2008-10-01

    Full Text Available A variable stability, blended-wing-body research mini-UAV was developed at the CSIR in South Africa. The purpose of the UAV was to study some of the aerodynamic design and control issues associated with flying wing geometries and to develop a...

  15. Flapping-wing mechanical butterfly on a wheel

    Science.gov (United States)

    Godoy-Diana, Ramiro; Thiria, Benjamin; Pradal, Daniel

    2009-11-01

    We examine the propulsive performance of a flapping-wing device turning on a ``merry-go-round'' type base. The two-wing flapper is attached to a mast that is ball-bearing mounted to a central shaft in such a way that the thrust force produced by the wings makes the flapper turn around this shaft. The oscillating lift force produced by the flapping wings is aligned with the mast to avoid vibration of the system. A turning contact allows to power the motor that drives the wings. We measure power consumption and cruising speed as a function of flapping frequency and amplitude as well as wing flexibility. The design of the wings permits to change independently their flexibility in the span-wise and chord-wise directions and PIV measurements in various planes let us examine the vorticity field around the device. A complete study of the effect of wing flexibility on the propulsive performance of the system will be presented at the conference.

  16. Use of wing morphometry for the discrimination of some Cerceris ...

    African Journals Online (AJOL)

    The outline analysis, in which geometric and traditional morphometry potentials are insufficient, was performed by using the Fourier transformation. As a result of the comprehensive wing morphometry study, it was found that both Cerceris species can be distinguished according to their wing structures and the metric ...

  17. Energy-based Aeroelastic Analysis and Optimisation of Morphing Wings

    NARCIS (Netherlands)

    De Breuker, R.

    2011-01-01

    Morphing aircraft can change their shape radically when confronted with a variety of conflicting flight conditions throughout their mission. For instance the F-14 Tomcat fighter aircraft, known from the movie Top Gun, was able to sweep its wings from a straight wing configuration to a highly swept

  18. COLIBRI : A hovering flapping twin-wing robot

    NARCIS (Netherlands)

    Roshanbin, A.; Altartouri, H.; Karasek, M.; Preumont, André

    2017-01-01

    This paper describes the results of a six-year project aiming at designing and constructing a flapping twin-wing robot of the size of hummingbird (Colibri in French) capable of hovering. Our prototype has a total mass of 22 g, a wing span of 21 cm and a flapping frequency of 22 Hz; it is actively

  19. Design, Development and Testing of Shape Shifting Wing Model

    Directory of Open Access Journals (Sweden)

    Dean Ninian

    2017-11-01

    Full Text Available The design and development of morphing (shape shifting aircraft wings—an innovative technology that has the potential to increase the aerodynamic efficiency and reduce noise signatures of aircrafts—was carried out. This research was focused on reducing lift-induced drag at the flaps of the aerofoil and to improve the design to achieve the optimum aerodynamic efficiency. Simulation revealed a 10.8% coefficient of lift increase for the initial morphing wing and 15.4% for the optimized morphing wing as compared to conventional wing design. At angles of attack of 0, 5, 10 and 15 degrees, the optimized wing has an increase in lift-to-drag ratio of 18.3%, 10.5%, 10.6% and 4% respectively when compared with the conventional wing. Simulations also showed that there is a significant improvement on pressure distribution over the lower surface of the morphing wing aerofoil. The increase in flow smoothness and reduction in vortex size reduced pressure drag along the trailing edge of the wing as a result an increase in pressure on the lower surface was experienced. A morphing wing reduced the size of the vortices and therefore the noise levels measured were reduced by up to 50%.

  20. Temporal variation of wing geometry in Aedes albopictus

    Directory of Open Access Journals (Sweden)

    Paloma Oliveira Vidal

    2012-12-01

    Full Text Available Although native to the tropical and subtropical areas of Southeast Asia, Aedes albopictus is now found on five continents, primarily due to its great capacity to adapt to different environments. This species is considered a secondary vector of dengue virus in several countries. Wing geometric morphometrics is widely used to furnish morphological markers for the characterisation and identification of species of medical importance and for the assessment of population dynamics. In this work, we investigated the metric differentiation of the wings of Ae. albopictus samples collected over a four-year period (2007-2010 in São Paulo, Brazil. Wing size significantly decreased during this period for both sexes and the wing shape also changed over time, with the wing shapes of males showing greater differences after 2008 and those of females differing more after 2009. Given that the wings play sex-specific roles, these findings suggest that the males and females could be affected by differential evolutionary pressures. Consistent with this hypothesis, a sexually dimorphic pattern was detected and quantified: the females were larger than the males (with respect to the mean and had a distinct wing shape, regardless of allometric effects. In conclusion, wing alterations, particularly those involving shape, are a sensitive indicator of microevolutionary processes in this species.

  1. Temporal variation of wing geometry in Aedes albopictus.

    Science.gov (United States)

    Vidal, Paloma Oliveira; Carvalho, Eneas; Suesdek, Lincoln

    2012-12-01

    Although native to the tropical and subtropical areas of Southeast Asia, Aedes albopictus is now found on five continents, primarily due to its great capacity to adapt to different environments. This species is considered a secondary vector of dengue virus in several countries. Wing geometric morphometrics is widely used to furnish morphological markers for the characterisation and identification of species of medical importance and for the assessment of population dynamics. In this work, we investigated the metric differentiation of the wings of Ae. albopictus samples collected over a four-year period (2007-2010) in São Paulo, Brazil. Wing size significantly decreased during this period for both sexes and the wing shape also changed over time, with the wing shapes of males showing greater differences after 2008 and those of females differing more after 2009. Given that the wings play sex-specific roles, these findings suggest that the males and females could be affected by differential evolutionary pressures. Consistent with this hypothesis, a sexually dimorphic pattern was detected and quantified: the females were larger than the males (with respect to the mean) and had a distinct wing shape, regardless of allometric effects. In conclusion, wing alterations, particularly those involving shape, are a sensitive indicator of microevolutionary processes in this species.

  2. Stable structural color patterns displayed on transparent insect wings.

    Science.gov (United States)

    Shevtsova, Ekaterina; Hansson, Christer; Janzen, Daniel H; Kjærandsen, Jostein

    2011-01-11

    Color patterns play central roles in the behavior of insects, and are important traits for taxonomic studies. Here we report striking and stable structural color patterns--wing interference patterns (WIPs)--in the transparent wings of small Hymenoptera and Diptera, patterns that have been largely overlooked by biologists. These extremely thin wings reflect vivid color patterns caused by thin film interference. The visibility of these patterns is affected by the way the insects display their wings against various backgrounds with different light properties. The specific color sequence displayed lacks pure red and matches the color vision of most insects, strongly suggesting that the biological significance of WIPs lies in visual signaling. Taxon-specific color patterns are formed by uneven membrane thickness, pigmentation, venation, and hair placement. The optically refracted pattern is also stabilized by microstructures of the wing such as membrane corrugations and spherical cell structures that reinforce the pattern and make it essentially noniridescent over a large range of light incidences. WIPs can be applied to map the micromorphology of wings through direct observation and are useful in several fields of biology. We demonstrate their usefulness as identification patterns to solve cases of cryptic species complexes in tiny parasitic wasps, and indicate their potentials for research on the genetic control of wing development through direct links between the transregulatory wing landscape and interference patterns we observe in Drosophila model species. Some species display sexually dimorphic WIPs, suggesting sexual selection as one of the driving forces for their evolution.

  3. Hydraulic Evaluation of the Crest Wing Wave Energy Converter

    DEFF Research Database (Denmark)

    Kofoed, Jens Peter; Antonishen, Michael Patrick

    This report presents the results of an experimental study of the wave energy converting abilities of the Crest Wing wave energy converter (WEC). The Crest Wing is a WEC that uses its movement in matching the shape of an oncoming wave to generate power. Model tests have been performed using a scal...

  4. Unsteady Aerodynamics of Flapping Wing of a Bird

    Directory of Open Access Journals (Sweden)

    M. Agoes Moelyadi

    2013-04-01

    Full Text Available The unsteady flow behavior and time-dependent aerodynamic characteristics of the flapping motion of a bird’s wing were investigated using a computational method. During flapping, aerodynamic interactions between bird wing surfaces and surrounding flow may occur, generating local time-dependent flow changes in the flow field and aerodynamic load of birds. To study the effect of flapping speed on unsteady aerodynamic load, two kinds of computational simulations were carried out, namely a quasi-steady and an unsteady simulation. To mimic the movement of the down-stroke and the upstroke of a bird, the flapping path accorded to a sinus function, with the wing attitude changing in dihedral angle and time. The computations of time-dependent viscous flow were based on the solution of the Reynolds Averaged Navier-Stokes equations by applying the k-e turbulence model. In addition, the discretization for the computational domain around the model used multi-block structured grid to provide more accuracy in capturing viscous flow, especially in the vicinity of the wing and body surfaces, to obtain a proper wing-body geometry model. For this research, the seagull bird was chosen, which has high aspect ratio wings with pointed wing-tips and a high camber wing section. The results include mesh movement, velocity contours as well as aerodynamic coefficients of the flapping motion of the bird at various flapping frequencies.

  5. Closed-type wing for drones: positive and negative characteristics

    Directory of Open Access Journals (Sweden)

    Leonid I. Gretchihin

    2014-02-01

    Full Text Available The paper presents the aerodynamics of a wing of a closed oval ellipsoidal shape, designed with the use of the molecular-kinetic theory. The positive and negative characteristics of aircraft - drones with an oval wing are described. The theoretical calculations have been experimentally checked.

  6. DETERMINATION OF COMMERCIAL AIRCRAFT WING GEOMETRY DURING THE FLIGHT

    Directory of Open Access Journals (Sweden)

    V. I. Shevyakov

    2015-01-01

    Full Text Available The article deals with the task of determination of wing shape for sub-sonic commercial aircraft by photogrammetric method. It provides the procedure for measurements taken on ground and in flight. It also provides the outcome of wing twist for commercial aircraft at cruise.

  7. Global Local Structural Optimization of Transportation Aircraft Wings

    NARCIS (Netherlands)

    Ciampa, P.D.; Nagel, B.; Van Tooren, M.J.L.

    2010-01-01

    The study presents a multilevel optimization methodology for the preliminary structural design of transportation aircraft wings. A global level is defined by taking into account the primary wing structural components (i.e., ribs, spars and skin) which are explicitly modeled by shell layered finite

  8. Wing flexibility effects in clap-and-fling

    NARCIS (Netherlands)

    Percin, M.; Hu, Y.; Van Oudheusden, B.W.; Remes, B.; Scarano, F.

    2011-01-01

    The work explores the use of time-resolved tomographic PIV measurements to study a flapping-wing model, the related vortex generation mechanisms and the effect of wing flexibility on the clap-and-fling movement in particular. An experimental setup is designed and realized in a water tank by use of a

  9. 14 CFR 23.302 - Canard or tandem wing configurations.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Canard or tandem wing configurations. 23.302 Section 23.302 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Structure General § 23.302 Canard or tandem wing...

  10. Wind fluctuations over the North Sea

    DEFF Research Database (Denmark)

    Vincent, Claire Louise; Pinson, Pierre; Giebel, Gregor

    2011-01-01

    Climatological patterns in wind speed fluctuations with periods of 1 min to 10 h are analysed using data from a meteorological mast in the Danish North Sea. Fluctuations on these time scales are of particular relevance to the effective management of the power supply from large wind farms. The Hil......Climatological patterns in wind speed fluctuations with periods of 1 min to 10 h are analysed using data from a meteorological mast in the Danish North Sea. Fluctuations on these time scales are of particular relevance to the effective management of the power supply from large wind farms...... a certain class of conditions can be found. Here, the HHT is applied to create conditional spectra which demonstrate patterns in the occurrence of severe wind variability. It is shown that wind fluctuations over the North Sea are more severe for westerly flow than for easterly flow, and that severe...... fluctuations are often observed in the vicinity of precipitation. The most severe wind fluctuations occur in the autumn and winter seasons, and are slightly more common when the pressure tendency is rising. Further, it is found that the wind is more variable for atmospherically unstable conditions than...

  11. Fluctuations and structure of amphiphilic films

    International Nuclear Information System (INIS)

    Gourier, CH.

    1996-01-01

    This thesis is divided in three parts.The first part exposes in a theoretical point of view, how the fluctuations spectrum of an amphiphilic film is governed by its properties and its bidimensional characteristics.The measurements of fluctuations spectra of an interface are accessible with the measurement of intensity that interface diffuses out of the specular angle, we present in the second chapter the principles of the X rays diffusion by a real interface and see how the diffuse diffusion experiments allow to determine the fluctuations spectrum of an amphiphilic film. The second part is devoted to the different experimental techniques that have allowed to realize the study of fluctuation as well as the structural study.The third part is devoted to experimental results concerning the measurements of fluctuations spectra and to the study of the structure of amphiphilic films. We show that it is possible by using an intense source of X rays (ESRF: European Synchrotron Radiation Facility) to measure the water and amphiphilic films fluctuations spectra until molecular scales. The last chapter is devoted to the structural study and film fluctuations made of di-acetylenic molecules. (N.C.)

  12. Mixed ice accretion on aircraft wings

    Science.gov (United States)

    Janjua, Zaid A.; Turnbull, Barbara; Hibberd, Stephen; Choi, Kwing-So

    2018-02-01

    Ice accretion is a problematic natural phenomenon that affects a wide range of engineering applications including power cables, radio masts, and wind turbines. Accretion on aircraft wings occurs when supercooled water droplets freeze instantaneously on impact to form rime ice or runback as water along the wing to form glaze ice. Most models to date have ignored the accretion of mixed ice, which is a combination of rime and glaze. A parameter we term the "freezing fraction" is defined as the fraction of a supercooled droplet that freezes on impact with the top surface of the accretion ice to explore the concept of mixed ice accretion. Additionally we consider different "packing densities" of rime ice, mimicking the different bulk rime densities observed in nature. Ice accretion is considered in four stages: rime, primary mixed, secondary mixed, and glaze ice. Predictions match with existing models and experimental data in the limiting rime and glaze cases. The mixed ice formulation however provides additional insight into the composition of the overall ice structure, which ultimately influences adhesion and ice thickness, and shows that for similar atmospheric parameter ranges, this simple mixed ice description leads to very different accretion rates. A simple one-dimensional energy balance was solved to show how this freezing fraction parameter increases with decrease in atmospheric temperature, with lower freezing fraction promoting glaze ice accretion.

  13. Computation of Lifting Wing-Flap Configurations

    Science.gov (United States)

    Cantwell, Brian; Kwak, Dochan

    1996-01-01

    Research has been carried out on the computation of lifting wing-flap configurations. The long term goal of the research is to develop improved computational tools for the analysis and design of high lift systems. Results show that state-of-the-art computational methods are sufficient to predict time-averaged lift and overall flow field characteristics on simple high-lift configurations. Recently there has been an increased interest in the problem of airframe generated noise and experiments carried out in the 7 x 10 wind tunnel at NASA Ames have identified the flap edge as an important source of noise. A follow-on set of experiments will be conducted toward the end of 1995. The computations being carried out under this project are coordinated with these experiments. In particular, the model geometry being used in the computations is the same as that in the experiments. The geometry consists of a NACA 63-215 Mod B airfoil section which spans the 7 x lO tunnel. The wing is unswept and has an aspect ratio of two. A 30% chord Fowler flap is deployed modifications of the flap edge geometry have been shown to be effective in reducing noise and the existing code is currently being used to compute the effect of a modified geometry on the edge flow.

  14. New aeroelastic studies for a morphing wing

    Directory of Open Access Journals (Sweden)

    Ruxandra Mihaela BOTEZ*

    2012-06-01

    Full Text Available For this study, the upper surface of a rectangular finite aspect ratio wing, with a laminar airfoil cross-section, was made of a carbon-Kevlar composite material flexible skin. This flexible skin was morphed by use of Shape Memory Alloy actuators for 35 test cases characterized by combinations of Mach numbers, Reynolds numbers and angles of attack. The Mach numbers varied from 0.2 to 0.3 and the angles of attack ranged between -1° and 2°. The optimized airfoils were determined by use of the CFD XFoil code. The purpose of this aeroelastic study was to determine the flutter conditions to be avoided during wind tunnel tests. These studies show that aeroelastic instabilities for the morphing configurations considered appeared at Mach number 0.55, which was higher than the wind tunnel Mach number limit speed of 0.3. The wind tunnel tests could thus be performed safely in the 6’×9’ wind tunnel at the Institute for Aerospace Research at the National Research Council Canada (IAR/NRC, where the new aeroelastic studies, applied on morphing wings, were validated.

  15. Take your seats: Leftward asymmetry in classroom seating choice

    Directory of Open Access Journals (Sweden)

    Victoria Lynn Harms

    2015-08-01

    Full Text Available Despite an overall body symmetry, human behaviour is full of examples of asymmetry, from writing or gesturing to kissing and cradling. Prior research has revealed that theatre patrons show a bias towards sitting on the right side of a movie theatre. Two competing theories have attempted to explain this seating asymmetry: one posits that expectation of processing demand drives the bias; the other posits that basic motor asymmetries drive the bias. To test these theories we assessed the real-world classroom seating choices of university students using photographs. A bias for students to choose seats on the left side of the classroom was observed, in contrast to the right side bias observed in theatre seating studies. These results provide evidence in support of a processing-expectation bias.

  16. PERANAN KONSERVATISME PADA INFORMATION ASYMMETRY: SUATU TINJAUAN TEORETIS

    Directory of Open Access Journals (Sweden)

    I G.A.N. BUDIASIH

    2011-07-01

    Full Text Available Conservatism is one of mechanisms of corporate governance that could reduce managers’ capability to manipulate and overstate financial report, especially financial performance, so cash flow and company’s value could be increased. Conservatism is also important in decreasing agency cost and increasing the quality of financial information to increase company’s value and the share price. Financial statement employing principle of conservatism could reduce management chance to manipulate financial report and decrease deadweight loss as an agency cost emerged due to information asymmetry. Thus it can be said that conservative financial statement could reduce information asymmetry. Information asymmetry can be handled by forcing management to fully disclose the company’s condition on the financial statement. Another way is to monitor management conduct by employing independent auditor.

  17. Right-frontal cortical asymmetry predicts increased proneness to nostalgia.

    Science.gov (United States)

    Tullett, Alexa M; Wildschut, Tim; Sedikides, Constantine; Inzlicht, Michael

    2015-08-01

    Nostalgia is often triggered by feelings-such as sadness, loneliness, or meaninglessness-that are typically associated with withdrawal motivation. Here, we examined whether a trait tendency to experience withdrawal motivation is associated with nostalgia proneness. Past work indicates that baseline right-frontal cortical asymmetry is a neural correlate of withdrawal-related motivation. We therefore hypothesized that higher baseline levels of right-frontal asymmetry would predict increased proneness to nostalgia. We assessed participants' baseline levels of frontal cortical activity using EEG. Results supported the hypothesis and demonstrated that the association between relative right-frontal asymmetry and increased nostalgia remained significant when controlling for the Big Five personality traits. Overall, these findings indicate that individuals with a stronger dispositional tendency to experience withdrawal-related motivation are more prone to nostalgia. © 2015 Society for Psychophysiological Research.

  18. Azimuthal asymmetries in the unpolarized SIDIS cross section at COMPASS

    CERN Document Server

    Sbrizzai, G

    2011-01-01

    The study of the spin structure of the nucleon and of the effects rising from the quarks transverse momentum are part of the scientific program of COMPASS, a fixed target experiment at the CERN SPS. The azimuthal asymmetries which appear in the cross-section of SIDIS off unpolarized targets can give insights on the intrinsic momentum structure of the nucleon and on the possible correlation between transverse spin and transverse momentum of the quarks. Here we present the new results for these asymmetries obtained from the COMPASS data collected with a 160 GeV/c positive muon beam impinging on a $^6LiD$ target. The asymmetries are measured for both positive and negative hadrons, and their dependence on several kinematical variable has been studied

  19. MANDIBULAR ASYMMETRY CHARACTERIZATION USING GENERALIZED TENSOR-BASED MORPHOMETRY.

    Science.gov (United States)

    Paniagua, Beatriz; Alhadidi, Abeer; Cevidanes, Lucia; Styner, Martin; Oguz, Ipek

    2011-12-31

    Quantitative assessment of facial asymmetry is crucial for successful planning of corrective surgery. We propose a tensor-based morphometry (TBM) framework to locate and quantify asymmetry using 3D CBCT images. To this end, we compute a rigid transformation between the mandible segmentation and its mirror image, which yields global rotation and translation with respect to the cranial base to guide the surgery's first stage. Next, we nonrigidly register the rigidly aligned images and use TBM methods to locally analyze the deformation field. This yields data on the location, amount and direction of "growth" (or "shrinkage") between the left and right sides. We visualize this data in a volumetric manner and via scalar and vector maps on the mandibular surface to provide the surgeon with optimal understanding of the patient's anatomy. We illustrate the feasibility and strength of our technique on 3 representative patients with a wide range of facial asymmetries.

  20. Visual Representation Determines Search Difficulty: Explaining Visual Search Asymmetries

    Directory of Open Access Journals (Sweden)

    Neil eBruce

    2011-07-01

    Full Text Available In visual search experiments there exist a variety of experimental paradigms in which a symmetric set of experimental conditions yields asymmetric corresponding task performance. There are a variety of examples of this that currently lack a satisfactory explanation. In this paper, we demonstrate that distinct classes of asymmetries may be explained by virtue of a few simple conditions that are consistent with current thinking surrounding computational modeling of visual search and coding in the primate brain. This includes a detailed look at the role that stimulus familiarity plays in the determination of search performance. Overall, we demonstrate that all of these asymmetries have a common origin, namely, they are a consequence of the encoding that appears in the visual cortex. The analysis associated with these cases yields insight into the problem of visual search in general and predictions of novel search asymmetries.