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Sample records for fatter the asymmetric effects

  1. Why even active people get fatter--the asymmetric effects ofincreasing and decreasing exercise

    SciTech Connect

    Williams, Paul T.

    2006-01-06

    Background: Public health policies for preventing obesityneed guidelines for active individuals who are at risk due to exerciserecidivism. Methods: Changes in adiposity were compared to the runningdistances at baseline and follow-up in men and women whose reportedexercise increased (N=4,632 and 1,953, respectively) or decreased (17,280and 5,970, respectively) during 7.7 years of follow-up. Results: PerDelta km/wk, decreases in running distance caused over four-fold greaterweight gain between 0-8 km/wk (slope+-SE, males: -0.068+ -0.005 kg/m2,females: -0.080+-0.01 kg/m2) than between 32-48 km/wk (-0.017+-0.002 and-0.010+-0.005 kg/m2, respectively). In contrast, increases in runningdistance produced the smallest weight losses between 0-8 km/wk andstatistically significant weight loss only above 16 km/wk in males and 32km/wk in females. Above 32 km/wk (30 kcal/kg) in men and 16 km/wk (15kcal/kg) in women, weight loss from increasing exercise was equal to orgreater than weight gained with decreasing exercise, otherwise weightgain exceeded weight loss. Substantial weight gain occurred in runnerswho quit running, which would be mostly retained with resumed activity.Conclusion: Public health recommendations should warn against the risksof irreversible weight gain with exercise cessation. Weight gained due toreductions in exercise below 30 kcal/kg in men and 15 kcal/kg in womenmay not be reversed by resuming prior activity. Current IOM guidelines(i.e., maintain total energy expenditure at 160 percent of basal) agreewith the men s exercise threshold for symmetric weight change withchanging exercise levels.

  2. Effect of spray-chilling on quality of beef from lean and fatter carcasses.

    PubMed

    Hippe, C L; Field, R A; Ray, B; Russell, W C

    1991-01-01

    Carcasses from five trim cows and five choice steers were used to study the effects of spray-chilling on cooler shrink, chill rate, purge loss from vacuum-packaged cuts, cook loss, shear values and bacterial growth. Spray-chilling reduced cooler shrink but had no effect on chill rate, purge loss from vacuum-packaged cuts, cook loss or shear values. Aerobes, facultative anaerobes, aerobic psychrotrophs, facultative anaerobic psychrotrophs and lactic acid bacteria all tended to be higher on rounds from spray-chilled sides. Leaner (and lighter) cow carcasses chilled faster and had lost a higher percentage of their weight at 24 h than fatter and heavier steer carcasses. The leaner carcasses had higher bacterial counts initially and throughout storage. This difference may have been due to differences in the level of initial contamination during dressing and not due to the carcasses' leanness. Purge-weight loss for each carcass increased and cooking weight loss decreased with increased storage times, making the total weight loss from meat aged 5 vs 10 wk similar. PMID:2005011

  3. Applying the Helmholtz illusion to fashion: horizontal stripes won't make you look fatter.

    PubMed

    Thompson, Peter; Mikellidou, Kyriaki

    2011-01-01

    A square composed of horizontal lines appears taller and narrower than an identical square made up of vertical lines. Reporting this illusion, Hermann von Helmholtz noted that such illusions, in which filled space seems to be larger than unfilled space, were common in everyday life, adding the observation that ladies' frocks with horizontal stripes make the figure look taller. As this assertion runs counter to modern popular belief, we have investigated whether vertical or horizontal stripes on clothing should make the wearer appear taller or fatter. We find that a rectangle of vertical stripes needs to be extended by 7.1% vertically to match the height of a square of horizontal stripes and that a rectangle of horizontal stripes must be made 4.5% wider than a square of vertical stripes to match its perceived width. This illusion holds when the horizontal or vertical lines are on the dress of a line drawing of a woman. We have examined the claim that these effects apply only for 2-dimensional figures in an experiment with 3-D cylinders and find no support for the notion that horizontal lines would be 'fattening' on clothes. Significantly, the illusion persists when the horizontal or vertical lines are on pictures of a real half-body mannequin viewed stereoscopically. All the evidence supports Helmholtz's original assertion. PMID:23145226

  4. Heart Attacks Striking Younger, Fatter Americans

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_157946.html Heart Attacks Striking Younger, Fatter Americans: Study Doctors, patients need ... 24, 2016 THURSDAY, March 24, 2016 (HealthDay News) -- Heart attack victims in the United States are becoming younger ...

  5. The Marriage of Rigorous Academics and Technical Instruction with State-of-the-Art Technology: A Success Story of the William T. McFatter Technical High School

    ERIC Educational Resources Information Center

    Blasik, Katherine; Williams, Richard G.; Johnson, Jeanette; Boegli, D. Robert

    2004-01-01

    The search for high school reform leads to William T. McFatter Technical High School in Broward County Public Schools, Florida. The purpose of this article is to highlight key information about the school and to demonstrate the success of its rigorous academic and technical instruction with state-of-the-art technology. By sharing this…

  6. How dieting makes the lean fatter: from a perspective of body composition autoregulation through adipostats and proteinstats awaiting discovery.

    PubMed

    Dulloo, A G; Jacquet, J; Montani, J-P; Schutz, Y

    2015-02-01

    Whether dieting makes people fatter has been a subject of considerable controversy over the past 30 years. More recent analysis of several prospective studies suggest, however, that it is dieting to lose weight in people who are in the healthy normal range of body weight, rather than in those who are overweight or obese, that most strongly and consistently predict future weight gain. This paper analyses the ongoing arguments in the debate about whether repeated dieting to lose weight in normal-weight people represents unsuccessful attempts to counter genetic and familial predispositions to obesity, a psychosocial reaction to the fear of fatness or that dieting per se confers risks for fatness and hence a contributing factor to the obesity epidemic. In addressing the biological plausibility that dieting predisposes the lean (rather than the overweight or obese) to regaining more body fat than what had been lost (i.e. fat overshooting), it integrates the results derived from the re-analysis of body composition data on fat mass and fat-free mass (FFM) losses and recoveries from human studies of experimental energy restriction and refeeding. These suggest that feedback signals from the depletion of both fat mass (i.e. adipostats) and FFM (i.e. proteinstats) contribute to weight regain through the modulation of energy intake and adaptive thermogenesis, and that a faster rate of fat recovery relative to FFM recovery (i.e. preferential catch-up fat) is a central outcome of body composition autoregulation in lean individuals. Such a temporal desynchronization in the restoration of the body's fat vs. FFM results in a state of hyperphagia that persists beyond complete recovery of fat mass and interestingly until FFM is fully recovered. However, as this completion of FFM recovery is also accompanied by fat deposition, excess fat accumulates. In other words, fat overshooting is a prerequisite to allow complete recovery of FFM. This confers biological plausibility for post

  7. The Future Liver of the Asia Pacific: Fatter and Firmer from More Fructose and Fortune?

    PubMed Central

    Mahady, Suzanne E.; George, Jacob

    2012-01-01

    The Asia Pacific region is the most diverse and the most populous region in the world. Recent socioeconomic changes have resulted in an emerging epidemic of non-communicable diseases such as type 2 diabetes and nonalcoholic fatty liver disease. The prevalence of nonalcoholic fatty liver disease in Asian Pacific countries now approximates that seen in Western countries. This increase is fueled by rising obesity, partly due to adoption of Western style diets and exposure to compounds such as high fructose corn syrup that are not included in traditional diets. Furthermore, South Asian populations may be more genetically susceptible via the inheritance of polymorphisms in apolipoprotein 3 that increase insulin resistance and nonalcoholic fatty liver disease. Importantly, there remains a substantial lack of data on the incidence and natural history of nonalcoholic steatohepatitis and subsequent complications such as hepatocellular carcinoma in Asian Pacific populations. This information gap prevents estimation of current and future disease burden and impedes efforts to lobby health policymakers to improve public health measures, as given the size of Asian Pacific populations, prevention rather than treatment of non-communicable diseases remains key. This review article addresses these issues and highlights research priorities for nonalcoholic fatty liver disease within the Asia Pacific region. PMID:25755484

  8. The future liver of the Asia pacific: fatter and firmer from more fructose and fortune?

    PubMed

    Mahady, Suzanne E; George, Jacob

    2013-06-01

    The Asia Pacific region is the most diverse and the most populous region in the world. Recent socioeconomic changes have resulted in an emerging epidemic of non-communicable diseases such as type 2 diabetes and nonalcoholic fatty liver disease. The prevalence of nonalcoholic fatty liver disease in Asian Pacific countries now approximates that seen in Western countries. This increase is fueled by rising obesity, partly due to adoption of Western style diets and exposure to compounds such as high fructose corn syrup that are not included in traditional diets. Furthermore, South Asian populations may be more genetically susceptible via the inheritance of polymorphisms in apolipoprotein 3 that increase insulin resistance and nonalcoholic fatty liver disease. Importantly, there remains a substantial lack of data on the incidence and natural history of nonalcoholic steatohepatitis and subsequent complications such as hepatocellular carcinoma in Asian Pacific populations. This information gap prevents estimation of current and future disease burden and impedes efforts to lobby health policymakers to improve public health measures, as given the size of Asian Pacific populations, prevention rather than treatment of non-communicable diseases remains key. This review article addresses these issues and highlights research priorities for nonalcoholic fatty liver disease within the Asia Pacific region. PMID:25755484

  9. Asymmetric nonlinear response of the quantized Hall effect

    NASA Astrophysics Data System (ADS)

    Siddiki, A.; Horas, J.; Kupidura, D.; Wegscheider, W.; Ludwig, S.

    2010-11-01

    An asymmetric breakdown of the integer quantized Hall effect (IQHE) is investigated. This rectification effect is observed as a function of the current value and its direction in conjunction with an asymmetric lateral confinement potential defining the Hall bar. Our electrostatic definition of the Hall bar via Schottky gates allows a systematic control of the steepness of the confinement potential at the edges of the Hall bar. A softer edge (flatter confinement potential) results in more stable Hall plateaus, i.e. a breakdown at a larger current density. For one soft and one hard edge, the breakdown current depends on its direction, resembling rectification. This nonlinear magneto-transport effect confirms the predictions of an emerging screening theory of the IQHE.

  10. Attention modulation by proportion congruency: the asymmetrical list shifting effect.

    PubMed

    Abrahamse, Elger L; Duthoo, Wout; Notebaert, Wim; Risko, Evan F

    2013-09-01

    Proportion congruency effects represent hallmark phenomena in current theorizing about cognitive control. This is based on the notion that proportion congruency determines the relative levels of attention to relevant and irrelevant information in conflict tasks. However, little empirical evidence exists that uniquely supports such an attention modulation account; moreover, a rivaling account was recently proposed that attributes the effect of proportion congruency to mere contingency learning. In the present study, the influences of shifts in list-wide (Experiment 1) or item-specific (Experiment 2) proportion congruency were investigated. As predicted by attention modulation but not by contingency learning, strong asymmetries were observed in such shifting: An increase in the proportion of congruent trials had only limited impact on the size of the congruency effect when participants were initially trained with a mostly incongruent list, but the impact was substantial for an equivalent increase of incongruent trials when participants were initially trained with a mostly congruent list. This asymmetrical list shifting effect directly supports attention modulation by proportion congruency manipulations and as such provides a novel tool for exploring cognitive control. Implications of our findings for existing theories of cognitive control are discussed. PMID:23565794

  11. The effects of stretching exercise for upper trapezius on the asymmetric rate of bite force

    PubMed Central

    Lee, Bomjin; Lee, Joongsook; Yang, Jeongok; Heo, Kwangjin; Hwang, Hojin; Kim, Boyoung; Han, Dongwook

    2015-01-01

    [Purpose] The purpose of this study was to observe the effects of stretching the upper trapezius muscle on the asymmetric rate of bite force. [Subjects] Forty-seven female university students who had all their original teeth, had no disorders in the temporomandibular joints, and had never worn braces; participated in this study. [Methods] An occlusometer was used to measure biting forces. Subsequently, stretching exercises of the upper trapezius were performed. The subjects were divided into 3 groups at the start of the testing: the asymmetric rate of the first group was less than 10%; the asymmetric rate of the second group was between 10% and 20%; and the asymmetric rate of the third group was more than 20%. The stretching exercises were done on the dominant side of the upper trapezius. [Results] After the stretching exercises of the upper trapezius, the results showed that for the first group, whose asymmetric rate of biting force was less than 10%, there was a significant increase in asymmetric rate (from 5.1% to 10.3%). For the second group, whose asymmetric rate of biting force was measured to be between 10% and 20%, the asymmetric rate decreased from 14.7% to 14.3%, but the change was not statistically significant. For the third group, whose asymmetric rate of biting force was more than 20%, there was a significant decrease in asymmetric rate (from 27.8% to 12.6%). [Conclusion] We concluded that stretching exercises of the upper trapezius muscle had a direct effect on the asymmetric rate of biting force. PMID:26311945

  12. The effect of asymmetric payoff mechanism on evolutionary networked prisoner’s dilemma game

    NASA Astrophysics Data System (ADS)

    Du, Wen-Bo; Cao, Xian-Bin; Hu, Mao-Bin

    2009-12-01

    In social and biological systems, there are obvious individual divergence and asymmetric payoff phenomenon due to the strength, power and influence differences. In this paper, we introduce an asymmetric payoff mechanism to evolutionary Prisoner’s Dilemma Game (PDG) on scale-free networks. The co-effects of individual diversity and asymmetric payoff mechanism on the evolution of cooperation and the wealth distribution under different updating rules are investigated. Numerical results show that the cooperation is highly promoted when the hub nodes are favored in the payoff matrix, which seems to harm the interest of the majority. But the inequality of social wealth distribution grows with the unbalanced payoff rule. However, when the node difference is eliminated in the learning strategy, the asymmetric payoff rule will not affect the cooperation level. Our work may sharpen the understanding of the cooperative behavior and wealth inequality in the society.

  13. Isospin effects on fragmentation in the asymmetric reactions induced by neutron-rich targets

    NASA Astrophysics Data System (ADS)

    Sharma, Arun

    2016-05-01

    To understand the isospin effects in terms of fragment's yield in the asymmetric reactions induced by neutron-rich targets, we perform a theoretical study using isospin-dependent quantum molecular dynamics (IQMD) model. Simulations are carried out for reactions of 16O+Br80,84,92 and 16O+Ag108,113,122. We envision that fragments's yield in the asymmetric collisions induced by neutron-rich targets is better candidate to study isospin effects via symmetry energy and nucleon-nucleon (nn) cross-sections. Also, pronounced effects of symmetry energy and cross-sections can be found at lower and higher beam energies, respectively.

  14. Asymmetric Acoustic Propagation of Wave Packets Via the Self-Demodulation Effect.

    PubMed

    Devaux, Thibaut; Tournat, Vincent; Richoux, Olivier; Pagneux, Vincent

    2015-12-01

    This Letter presents the experimental characterization of nonreciprocal elastic wave transmission in a single-mode elastic waveguide. This asymmetric system is obtained by coupling a selection layer with a conversion layer: the selection component is provided by a phononic crystal, while the conversion is achieved by a nonlinear self-demodulation effect in a 3D unconsolidated granular medium. A quantitative experimental study of this acoustic rectifier indicates a high rectifying ratio, up to 10^{6}, with wide band (10 kHz) and an audible effect. Moreover, this system allows for wave-packet rectification and extends the future applications of asymmetric systems. PMID:26684119

  15. Asymmetric Acoustic Propagation of Wave Packets Via the Self-Demodulation Effect

    NASA Astrophysics Data System (ADS)

    Devaux, Thibaut; Tournat, Vincent; Richoux, Olivier; Pagneux, Vincent

    2015-12-01

    This Letter presents the experimental characterization of nonreciprocal elastic wave transmission in a single-mode elastic waveguide. This asymmetric system is obtained by coupling a selection layer with a conversion layer: the selection component is provided by a phononic crystal, while the conversion is achieved by a nonlinear self-demodulation effect in a 3D unconsolidated granular medium. A quantitative experimental study of this acoustic rectifier indicates a high rectifying ratio, up to 1 06, with wide band (10 kHz) and an audible effect. Moreover, this system allows for wave-packet rectification and extends the future applications of asymmetric systems.

  16. The Cyclopentadienyl Radical Revisited: the Effects of Asymmetric Deuteration of Jahn-Teller Molecules

    NASA Astrophysics Data System (ADS)

    Strom, Samantha; Liu, Jinjun

    2012-06-01

    Asymmetric deuteration of Jahn-Teller active molecules partially lifts the vibronic degeneracy and hence provides a unique approach to understanding the Jahn-Teller effect. Previously, a spectroscopic model was proposed and used to simulate the spectra of the asymmetrically deuterated isotopomers of the methoxy radical. The same model has been implemented and successfully simulated the previously reported high-resolution laser-induced fluorescence (LIF) spectra of the asymmetrically deuterated cyclopentadienyl radical (C_5H_4D and C_5HD_4). A joint fitting of the transitions from both of the zero-point levels of the tilde X ^2E''_1 ground electronic state, split by the asymmetric deuteration, to the tilde A ^2A''_2 state yields one set of molecular constants for both levels, which, when combined with molecular constants of C_5H_5 and C_5D_5, can be used to determine the molecular geometry and magnitude of the Jahn-Teller distortion. The main goal of this new investigation is to resolve the discrepancy between the experimentally determined and the ab initio calculated Jahn-Teller distortion. In addition, a theoretic model is proposed to quantitatively reproduce the splitting of the zero-point level due to the asymmetric deuteration and zero-point energies for the Jahn-Teller distorted structures around the conical intersection. D. G. Melnik, J. Liu, R. F. Curl, and T. A. Miller, Mol. Phys. 105, 529 (2007). D. G. Melnik, J. Liu, M.-W. Chen, T. A. Miller, and R. F. Curl, J. Chem. Phys. 135, 094310 (2011) L. Yu, D.W. Cullin, J.M. Williamson, and T.A. Miller, J. Chem. Phys. 98, 2682 (1993). M. J. Bearpark, M. A. Robb, and N. Yamamoto, Spectrochim. Acta Part A 55, 639 (1999).

  17. The Effect of Asymmetrical Signal Degradation on Binaural Speech Recognition in Children and Adults.

    ERIC Educational Resources Information Center

    Rothpletz, Ann M.; Tharpe, Anne Marie; Grantham, D. Wesley

    2004-01-01

    To determine the effect of asymmetrical signal degradation on binaural speech recognition, 28 children and 14 adults were administered a sentence recognition task amidst multitalker babble. There were 3 listening conditions: (a) monaural, with mild degradation in 1 ear; (b) binaural, with mild degradation in both ears (symmetric degradation); and…

  18. Asymmetric effects of luminance and chrominance in the watercolor illusion.

    PubMed

    Coia, Andrew J; Crognale, Michael A

    2014-01-01

    When bounded by a line of sufficient contrast, the desaturated hue of a colored line will spread over an enclosed area, an effect known as the watercolor illusion. The contrast of the two lines can be in luminance, chromaticity, or a combination of both. The effect is most salient when the enclosing line has greater contrast with the background than the line that induces the spreading color. In most prior experiments with watercolor spreading, the luminance of both lines has been lower than the background. An achromatic version of the illusion exists where a dark line will spread while being bounded by either a darker or brighter line. In a previous study we measured the strength of the watercolor effect in which the colored inducing line was isoluminant to the background, and found an illusion for both brighter and darker achromatic outer contours. We also found the strength of spreading is stronger for bluish (+S cone input) colors compared to yellowish (-S cone input) ones, when bounded by a dark line. The current study set out to measure the hue dependence of the watercolor illusion when inducing colors are flanked with brighter (increment) as opposed to darker outer lines. The asymmetry in the watercolor effect with S cone input was enhanced when the inducing contrast was an increment rather than a decrement. Further experiments explored the relationship between the perceived contrast of these chromatic lines when paired with luminance increments and decrements and revealed that the perceived contrast of luminance increments and decrements is dependent on which isoluminant color they are paired with. In addition to known hue asymmetries in the watercolor illusion there are asymmetries between luminance increments and decrements that are also hue dependent. These latter asymmetries may be related to the perceived contrast of the hue/luminance parings. PMID:25309396

  19. Asymmetric effects of luminance and chrominance in the watercolor illusion

    PubMed Central

    Coia, Andrew J.; Crognale, Michael A.

    2014-01-01

    When bounded by a line of sufficient contrast, the desaturated hue of a colored line will spread over an enclosed area, an effect known as the watercolor illusion. The contrast of the two lines can be in luminance, chromaticity, or a combination of both. The effect is most salient when the enclosing line has greater contrast with the background than the line that induces the spreading color. In most prior experiments with watercolor spreading, the luminance of both lines has been lower than the background. An achromatic version of the illusion exists where a dark line will spread while being bounded by either a darker or brighter line. In a previous study we measured the strength of the watercolor effect in which the colored inducing line was isoluminant to the background, and found an illusion for both brighter and darker achromatic outer contours. We also found the strength of spreading is stronger for bluish (+S cone input) colors compared to yellowish (−S cone input) ones, when bounded by a dark line. The current study set out to measure the hue dependence of the watercolor illusion when inducing colors are flanked with brighter (increment) as opposed to darker outer lines. The asymmetry in the watercolor effect with S cone input was enhanced when the inducing contrast was an increment rather than a decrement. Further experiments explored the relationship between the perceived contrast of these chromatic lines when paired with luminance increments and decrements and revealed that the perceived contrast of luminance increments and decrements is dependent on which isoluminant color they are paired with. In addition to known hue asymmetries in the watercolor illusion there are asymmetries between luminance increments and decrements that are also hue dependent. These latter asymmetries may be related to the perceived contrast of the hue/luminance parings. PMID:25309396

  20. Attention Modulation by Proportion Congruency: The Asymmetrical List Shifting Effect

    ERIC Educational Resources Information Center

    Abrahamse, Elger L.; Duthoo, Wout; Notebaert, Wim; Risko, Evan F.

    2013-01-01

    Proportion congruency effects represent hallmark phenomena in current theorizing about cognitive control. This is based on the notion that proportion congruency determines the relative levels of attention to relevant and irrelevant information in conflict tasks. However, little empirical evidence exists that uniquely supports such an attention…

  1. The effect of transverse crack upon parametric instability of a rotor-bearing system with an asymmetric disk

    NASA Astrophysics Data System (ADS)

    Han, Qinkai; Chu, Fulei

    2012-12-01

    It is well known that either the asymmetric disk or transverse crack brings parametric inertia (or stiffness) excitation to the rotor-bearing system. When both of them appear in a rotor system, the parametric instability behaviors have not gained sufficient attentions. Thus, the effect of transverse crack upon parametric instability of a rotor-bearing system with an asymmetric disk is studied. First, the finite element equations of motion are established for the asymmetric rotor system. Both the open and breathing transverse cracks are taken into account in the model. Then, the discrete state transition matrix (DSTM) method is introduced for numerically acquiring the instability regions. Based upon these, some computations for a practical asymmetric rotor system with open or breathing transverse crack are conducted, respectively. Variations of the primary and combination instability regions induced by the asymmetric disk with the crack depth are observed, and the effect of the orientation angle between the crack and asymmetric disk on various instability regions are discussed in detail. It is shown that for the asymmetric angle around 0, the existence of transverse (either open or breathing) crack has attenuation effect upon the instability regions. Under certain crack depth, the instability regions could be vanished by the transverse crack. When the asymmetric angle is around π/2, increasing the crack depth would enhance the instability regions.

  2. Temperature and impurity effects of the polaron in an asymmetric quantum dot

    NASA Astrophysics Data System (ADS)

    Shan, Shu-Ping; Liu, Ya-Min; Xiao, Jin-Lin

    2013-07-01

    Temperature and impurity effects of the ground state energy and the ground state binding energy in an asymmetric quantum dot are studied here by using the linear combination operator method. It is found that the ground state energy and the ground state binding energy increase with increasing temperature. The ground state energy is a decreasing function of the Coulomb bound potential, whereas the ground state binding energy is an increasing one.

  3. Unveiling the photonic spin Hall effect with asymmetric spin-dependent splitting.

    PubMed

    Zhou, Xinxing; Ling, Xiaohui

    2016-02-01

    The photonic spin Hall effect (SHE) manifests itself as the spin-dependent splitting of light beam. Usually, it shows a symmetric spin-dependent splitting, i.e., the left- and right-handed circularly polarized components are equally separated in position and intensity for linear polarization incidence. In this paper, we theoretically propose an asymmetric spin-dependent splitting at an air-glass interface under the illumination of elliptical polarization beam and experimentally demonstrate it with the weak measurement method. The left- and right-handed circularly polarized components show expectedly unequal intensity distributions and unexpectedly different spin-dependent shifts. Remarkably, the asymmetric spin-dependent splitting can be modulated by adjusting the handedness of incident polarization. The inherent physics behind this interesting phenomenon is attributed to the additional spatial Imbert-Fedorov shift. These findings offer us potential methods for developing new spin-based nanophotonic applications. PMID:26906868

  4. The effect of symmetrical and asymmetrical hearing impairment on music quality perception.

    PubMed

    Cai, Yuexin; Zhao, Fei; Chen, Yuebo; Liang, Maojin; Chen, Ling; Yang, Haidi; Xiong, Hao; Zhang, Xueyuan; Zheng, Yiqing

    2016-09-01

    The purpose of this study was to investigate the effect of symmetrical, asymmetrical and unilateral hearing impairment on music quality perception. Six validated music pieces in the categories of classical music, folk music and pop music were used to assess music quality in terms of its 'pleasantness', 'naturalness', 'fullness', 'roughness' and 'sharpness'. 58 participants with sensorineural hearing loss [20 with unilateral hearing loss (UHL), 20 with bilateral symmetrical hearing loss (BSHL) and 18 with bilateral asymmetrical hearing loss (BAHL)] and 29 normal hearing (NH) subjects participated in the present study. Hearing impaired (HI) participants had greater difficulty in overall music quality perception than NH participants. Participants with BSHL rated music pleasantness and naturalness to be higher than participants with BAHL. Moreover, the hearing thresholds of the better ears from BSHL and BAHL participants as well as the hearing thresholds of the worse ears from BSHL participants were negatively correlated to the pleasantness and naturalness perception. HI participants rated the familiar music pieces higher than unfamiliar music pieces in the three music categories. Music quality perception in participants with hearing impairment appeared to be affected by symmetry of hearing loss, degree of hearing loss and music familiarity when they were assessed using the music quality rating test (MQRT). This indicates that binaural symmetrical hearing is important to achieve a high level of music quality perception in HI listeners. This emphasizes the importance of provision of bilateral hearing assistive devices for people with asymmetrical hearing impairment. PMID:26611684

  5. Effects of surface perturbations on the asymmetric vortex flow over a slender body

    NASA Technical Reports Server (NTRS)

    Moskovitz, Cary A.; Dejarnette, Fred R.; Hall, Robert M.

    1988-01-01

    An experimental investigation of the effects of surface perturbations on the asymmetric flow past a slender body has been conducted for laminar flow conditions. Beads with diameters ranging from 3/32 to 12/32 in. were attached near the apex of a cone/cylinder model having a base diameter of 3.5 in. and a cone semiapex angle of 9 deg at an angle of attack of 40 deg in an attempt to alter the sense of the asymmetric vortex flow pattern. Circumferential position as well as longitudinal location were varied to determine the most effective bead position. Whether or not the beads were effective in controlling the magnitude and direction of the vortex asymmetries was determined by 3 circumferential rows of pressure taps and by a helium-bubble flow visualization technique. The most effective circumferential position was found to be approximately 140 deg from the windward ray. While holding this circumferential position constant, the effect of bead size at three stations further along the body was also investigated. It was found that the size of the bead necessary to reverse the asymmetry increased more rapidly than the growth in cylinder radius. In general, these results indicate that discrete geometric imperfections on a body's surface can force asymmetry in a given direction if they are sufficiently large relative to the local radius.

  6. The effects of asymmetric competition on the life history of Trinidadian guppies.

    PubMed

    Bassar, Ronald D; Childs, Dylan Z; Rees, Mark; Tuljapurkar, Shripad; Reznick, David N; Coulson, Tim

    2016-03-01

    The effects of asymmetric interactions on population dynamics has been widely investigated, but there has been little work aimed at understanding how life history parameters like generation time, life expectancy and the variance in lifetime reproductive success are impacted by different types of competition. We develop a new framework for incorporating trait-mediated density-dependence into size-structured models and use Trinidadian guppies to show how different types of competitive interactions impact life history parameters. Our results show the degree of symmetry in competitive interactions can have dramatic effects on the speed of the life history. For some vital rates, shifting the competitive superiority from small to large individuals resulted in a doubling of the generation time. Such large influences of competitive symmetry on the timescale of demographic processes, and hence evolution, highlights the interwoven nature of ecological and evolutionary processes and the importance of density-dependence in understanding eco-evolutionary dynamics. PMID:26843397

  7. A global analysis of the asymmetric effect of ENSO on extreme precipitation

    NASA Astrophysics Data System (ADS)

    Sun, Xun; Renard, Benjamin; Thyer, Mark; Westra, Seth; Lang, Michel

    2015-11-01

    The global and regional influence of the El Niño-Southern Oscillation (ENSO) phenomenon on extreme precipitation was analyzed using a global database comprising over 7000 high quality observation sites. To better quantify possible changes in relatively rare design-relevant precipitation quantiles (e.g. the 1 in 10 year event), a Bayesian regional extreme value model was used, which employed the Southern Oscillation Index (SOI) - a measure of ENSO - as a covariate. Regions found to be influenced by ENSO include parts of North and South America, southern and eastern Asia, South Africa, Australia and Europe. The season experiencing the greatest ENSO effect varies regionally, but in most of the ENSO-affected regions the strongest effect happens in boreal winter, during which time the 10-year precipitation for |SOI| = 20 (corresponding to either a strong El Niño or La Niña episode) can be up to 50% higher or lower than for SOI = 0 (a neutral phase). Importantly, the effect of ENSO on extreme precipitation is asymmetric, with most parts of the world experiencing a significant effect only for a single ENSO phase. This finding has important implications on the current understanding of how ENSO influences extreme precipitation, and will enable a more rigorous theoretical foundation for providing quantitative extreme precipitation intensity predictions at seasonal timescales. We anticipate that incorporating asymmetric impacts of ENSO on extreme precipitation will help lead to better-informed climate-adaptive design of flood-sensitive infrastructure.

  8. Postural effects of symmetrical and asymmetrical loads on the spines of schoolchildren.

    PubMed

    Negrini, Stefano; Negrini, Alberto

    2007-01-01

    The school backpack constitutes a daily load for schoolchildren: we set out to analyse the postural effects of this load, considering trunk rotation, shoulder asymmetry, thoracic kyphosis, lumbar lordosis, and sagittal and frontal decompensation from the plumbline. A group of 43 subjects (mean age = 12.5 +/- 0.5 years) were considered: average backpack loads and average time spent getting to/from home/school (7 min) had been determined in a previous study conducted on this population. Children were evaluated by means of an optoelectronic device in different conditions corresponding to their usual everyday school backpack activities: without load; bearing 12 (week maximum) and 8 (week average) kg symmetrical loads; bearing an 8 kg asymmetrical load; after fatigue due to backpack carrying (a 7-minute treadmill walking session bearing an 8 kg symmetrical load). Both types of load induce changes in posture: the symmetrical one in the sagittal plane, without statistical significant differences between 8 and 12 kg, and the asymmetrical one in all anatomical planes. Usual fatigue accentuates sagittal effects, but recovery of all parameters (except lumbar lordosis) follows removal of the load. The backpack load effect on schoolchildren posture should be more carefully evaluated in the future, even if we must bear in mind that laws protect workers to carry heavy loads but not children, and results in the literature support the hypothesis that back pain in youngsters is correlated with back pain in adulthood. PMID:17620121

  9. The Asymmetric Piers Hydrosilylation.

    PubMed

    Süsse, Lars; Hermeke, Julia; Oestreich, Martin

    2016-06-01

    An axially chiral, cyclic borane decorated with just one C6F5 group at the boron atom promotes the highly enantioselective hydrosilylation of acetophenone derivatives without assistance of an additional Lewis base (up to 99% ee). The reaction is an unprecedented asymmetric variant of Piers' B(C6F5)3-catalyzed carbonyl hydrosilylation. The steric congestion imparted by the 3,3'-disubstituted binaphthyl backbone of the borane catalyst as well as the use of reactive trihydrosilanes as reducing agents are keys to success. PMID:27212565

  10. Effect of asymmetric force on the condylar cartilage, subchondral bone and collagens in the temporomandibular joints.

    PubMed

    Zhang, Caixia; Xu, Yue; Cheng, Yangxi; Wu, Tuojiang; Li, Huang

    2015-04-01

    This study aimed to define the effects of asymmetric force on rat temporomandibular joints (TMJs). A total of 232 10-week-old rats were used in the experiment. Their left TMJs were kept forward and upward with 40g or 120g. The histological and osteogenic changes, as well as the expression of type I, II and III collagens were observed. Our results showed that the curve of the cartilage thickness changes in the anterior part of the treated side in the heavy force group (HS) decreased first and increased later during the strength and the recovery periods, while the reverse changes were shown in the middle and posterior parts. The cartilage thickness change on the other side in the heavy force group (HO) was the opposite. Additionally, the cartilage thickness change on the treated side and the other side of the light force group (LS and LO) were similar to but not as significantly changed as HS and HO. There were significant differences among the experimental groups. The subchondral bone trabecula also decreased after the pressure loading and removing, then recovered, without significant differences among these groups. Furthermore, more pathological changes such as fractures, bone cysts, the degradation of type II collagen and the increased expression of type III collagen were observed on the treated sides following the application of heavy force. In contrast, more osteogenesis and more active changes were found in the light force group. In conclusion, our study demonstrated that asymmetric force exerted different effects on the cartilage, subchondral bone and collagens of TMJs. Greater changes occurred in the heavy force group, and light force provided more benefits for TMJs remodelling. PMID:25703817

  11. Effects of asymmetric nanostructures on the extinction difference properties of actin biomolecules and filaments

    PubMed Central

    Khoo, E. H.; Leong, Eunice S. P.; Wu, S. J.; Phua, W. K.; Hor, Y. L.; Liu, Y. J.

    2016-01-01

    In this paper, symmetric and asymmetric tapering on the arms of the gammadion nanostructure is proposed to enhance both local field distribution and extinction difference (ED). The asymmetric tapered gammadion with tapering fraction (TF) of 0.67 is seen to have the largest ED and spatial local field distribution, producing a large wavelength shift of more than 50 percent as compared to the untapered gammadion nanostructures when immersed in a solution of actin molecules and filaments. The optical chirality, ζ shows that the larger local field amplitudes produced by the asymmetric designs increases the rate of chiral molecules excitation. This enhanced field is strongly rotating and highly sensitive to single molecules and larger filaments. Here, we show that the ED, optical chirality, sensitivity and rate of chiral molecules excitation can be improved by incorporating asymmetric designs into chiral gammadion nanostructures through tapering. PMID:26792371

  12. Effects of asymmetric nanostructures on the extinction difference properties of actin biomolecules and filaments

    NASA Astrophysics Data System (ADS)

    Khoo, E. H.; Leong, Eunice S. P.; Wu, S. J.; Phua, W. K.; Hor, Y. L.; Liu, Y. J.

    2016-01-01

    In this paper, symmetric and asymmetric tapering on the arms of the gammadion nanostructure is proposed to enhance both local field distribution and extinction difference (ED). The asymmetric tapered gammadion with tapering fraction (TF) of 0.67 is seen to have the largest ED and spatial local field distribution, producing a large wavelength shift of more than 50 percent as compared to the untapered gammadion nanostructures when immersed in a solution of actin molecules and filaments. The optical chirality, ζ shows that the larger local field amplitudes produced by the asymmetric designs increases the rate of chiral molecules excitation. This enhanced field is strongly rotating and highly sensitive to single molecules and larger filaments. Here, we show that the ED, optical chirality, sensitivity and rate of chiral molecules excitation can be improved by incorporating asymmetric designs into chiral gammadion nanostructures through tapering.

  13. Finite gyroradius effects in the electron outflow of asymmetric magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Norgren, C.; Graham, D. B.; Khotyaintsev, Yu. V.; André, M.; Vaivads, A.; Chen, L.-J.; Lindqvist, P.-A.; Marklund, G. T.; Ergun, R. E.; Magnes, W.; Strangeway, R. J.; Russell, C. T.; Torbert, R. B.; Paterson, W. R.; Gershman, D. J.; Dorelli, J. C.; Avanov, L. A.; Lavraud, B.; Saito, Y.; Giles, B. L.; Pollock, C. J.; Burch, J. L.

    2016-07-01

    We present observations of asymmetric magnetic reconnection showing evidence of electron demagnetization in the electron outflow. The observations were made at the magnetopause by the four Magnetospheric Multiscale (MMS) spacecraft, separated by ˜15 km. The reconnecting current sheet has negligible guide field, and all four spacecraft likely pass close to the electron diffusion region just south of the X line. In the electron outflow near the X line, all four spacecraft observe highly structured electron distributions in a region comparable to a few electron gyroradii. The distributions consist of a core with T∥>T⊥ and a nongyrotropic crescent perpendicular to the magnetic field. The crescents are associated with finite gyroradius effects of partly demagnetized electrons. These observations clearly demonstrate the manifestation of finite gyroradius effects in an electron-scale reconnection current sheet.

  14. The development of the asymmetrically dominated decoy effect in young children

    PubMed Central

    Zhen, Shanshan; Yu, Rongjun

    2016-01-01

    One classic example of context-independent violations is the asymmetrically dominated decoy effect, in which adding a decoy option (inferior option) to a set of original options often increases the individual’s preference for one option over the other original option. Despite the prevalence of this effect, little is known about its developmental origins. Moreover, it remains contentious whether the decoy effect is a result of biological evolution or is learned from social experience. Here, we investigated the decoy effect in 3- to 7-year-old children (n = 175) and young adults (n = 52) using a simple perceptual task. Results showed that older children (5-year-olds and 7-year-olds), but not younger children (3-year-olds), exhibited a decoy effect. Nevertheless, children as young as age 5 exhibited a decoy effect that was not significantly different from that shown by young adults. These findings suggest that humans start to appreciate the relative values of options at around age 5. PMID:26935899

  15. Effects of asymmetric sitting on spinal balance

    PubMed Central

    Woo, Hee Soon; Oh, Jong Chi; Won, Sung Yoon

    2016-01-01

    [Purpose] To investigate the effects of two common asymmetric sitting positions on spinal balance. [Subjects and Methods] Thirty-seven healthy subjects in their twenties were enrolled and randomly divided into two groups. Asymmetric positions of resting the chin on a hand and crossing the legs were performed by each group for 1 hour. After 1 hour, the subjects lay in the supine position again and spinal imbalance was measured using a device. [Results] After 1 hour of resting with the chin on a hand, sagittal imbalance, coronal imbalance, pelvic obliquity and lordosis angle presented spinal imbalance worsening of 1 hour of crossing legs, sagittal imbalance, pelvic torsion showed in mainly learned spinal imbalance living. [Conclusion] Good posture could be an innate ability, however it through habits. So this study is meaningful from the perspective of the importance of good posture. PMID:27065291

  16. Analysis of the effects of asymmetric faults in three-phase superconducting inductive fault current limiters

    NASA Astrophysics Data System (ADS)

    Ferreira, R.; Pina, J. M.; Vilhena, N.; Arsénio, P.; Pronto, A. G.; Martins, J.

    2014-05-01

    Inductive fault current limiters of magnetic shielding type can be described in terms of the excursion in the plane defined by flux linked with primary and line current, and this methodology has been previously applied to single-phase devices. Practical applications, however, require three-phase limiters, which, for the sake of compactness, may be built by three legged cores, instead of three single phase units. This has the advantage of using well established methods of power transformers industry, but the performance of the devices depends on the type of fault, e.g. phase to ground or phase to phase. For instance, in a three legged core, a phase to ground fault affects healthy phases, and these are the most frequent faults in distribution grids, where such systems are envisaged. The effects of asymmetric faults are analysed in this paper, by means of measured excursions in the linked flux-current plane.

  17. Flapping flight: effect of asymmetric kinematics

    NASA Astrophysics Data System (ADS)

    Pande, Nakul; Krithivasan, Siddharth; K. R., Sreenivas

    2014-11-01

    Flapping flight has received considerable attention in the past with its relevance in the design of micro-air vehicles. In this regard, asymmetric flapping of wings offers simple kinematics. Nevertheless, it leads to symmetry-breaking in the flow field and generation of sustained lift. It has been observed previously with flow visualization experiments and Discrete Vortex Method (DVM) simulations that if the down-stroke time period is lesser than the up-stroke time, there is a net downward momentum imparted to the fluid. This is seen as a switching the flow field from a four-jet (symmetric) to a two-jet (asymmetric) configuration when the stroke-time ratio is progressively varied. This symmetry breaking has been studied experimentally using Particle Image Velocimetry (PIV) across a range of Reynolds Numbers and asymmetry ratios. Results are also corroborated with results from 3-D numerical simulations. Study helps in shedding light on the effectiveness of asymmetric kinematics as a lift generation mechanism.

  18. The asymmetric effect of stress in the morphological instability of a growing thin film

    NASA Astrophysics Data System (ADS)

    Yu, Hong-Hui

    2005-09-01

    Many experiments have shown that films growing under tensile stress and compressive stress have different morphological instability behaviours. Departing from earlier theoretical works, which treated surface diffusion as the only kinetic process for bringing out the morphology change and assumed uniform growth rate along the surface, this paper studies the coupling between the deposition process and surface diffusion, to offer another possible mechanism for the asymmetric effect of stress. A nonlinear kinetic law, in which the activation energy of growth process is modified by local stress, is adopted. Linear stability analysis shows that if the growth rate is enhanced by tensile stress while being slowed by compressive stress, the surface instability, for a growing film under tension, could either be fully suppressed for perturbations of any wavelength, or occurs only when the wavelength is within an intermediate range; if the film is under compressive stress, the instability behaviour is similar to that obtained from considering surface diffusion alone, but with different amplitude on growth rate. Two characteristic lengths, one characterizing the competition between surface energy increase and strain energy reduction and the other representing the competition between surface diffusion and growth process, are identified. The thin film instability behaviour is largely determined by the ratio of these two lengths.

  19. The Effect of Asymmetrical Sample Training on Retention Functions for Hedonic Samples in Rats

    ERIC Educational Resources Information Center

    Simmons, Sabrina; Santi, Angelo

    2012-01-01

    Rats were trained in a symbolic delayed matching-to-sample task to discriminate sample stimuli that consisted of the presence of food or the absence of food. Asymmetrical sample training was provided in which one group was initially trained with only the food sample and the other group was initially trained with only the no-food sample. In…

  20. A new approach to extracting the RF parameters of asymmetric DG MOSFETs with the NQS effect

    NASA Astrophysics Data System (ADS)

    Pati, Sudhansu Kumar; Koley, Kalyan; Dutta, Arka; Mohankumar, N.; Sarkar, Chandan Kumar

    2013-11-01

    In analog circuit design an important parameter, from the perspective of superior device performance, is linearity. The DG MOSFET in asymmetric mode operation has been found to present a better linearity. In addition to that it provides, at the discretion of analog circuit designer, an additional degree of freedom, by providing independent bias control for the front and the back gates. Here a non-quasi-static (NQS) small signal model for DGMOSFET with asymmetric gate bias is proposed for extracting the parameters of the device using TCAD simulations. The parameters extracted here for analysis are the intrinsic front and back gate to drain capacitance, Cgd1 and Cgd2, the intrinsic front and back distributed channel resistance, Rgd1 and Rgd2 respectively, the transport delay, τm, and the inductance, Lsd. The parameter extraction model for an asymmetric DG MOSFET is validated with pre-established extracted parameter data, for symmetric DG MOSFET devices, from the available literature. The device simulation is performed with respect to frequency up to 100 GHz.

  1. The cosmology of asymmetric brane modified gravity

    SciTech Connect

    O'Callaghan, Eimear; Gregory, Ruth; Pourtsidou, Alkistis E-mail: ppxap1@nottingham.ac.uk

    2009-09-01

    We consider the asymmetric branes model of modified gravity, which can produce late time acceleration of the universe and compare the cosmology of this model to the standard ΛCDM model and to the DGP braneworld model. We show how the asymmetric cosmology at relevant physical scales can be regarded as a one-parameter extension of the DGP model, and investigate the effect of this additional parameter on the expansion history of the universe.

  2. Asymmetric dark matter and effective number of neutrinos

    NASA Astrophysics Data System (ADS)

    Kitabayashi, Teruyuki; Kurosawa, Yoshihiro

    2016-02-01

    We study the effect of the MeV-scale asymmetric dark matter annihilation on the effective number of neutrinos Neff at the epoch of the big bang nucleosynthesis. If the asymmetric dark matter χ couples more strongly to the neutrinos ν than to the photons γ and electrons e-, Γχ γ ,χ e≪Γχ ν , or Γχ γ ,χ e≫Γχ ν, the lower mass limit on the asymmetric dark matter is about 18 MeV for Neff≃3.0 .

  3. Ferroelectricity and tunneling electroresistance effect in asymmetric ferroelectric tunnel junctions

    NASA Astrophysics Data System (ADS)

    Tao, L. L.; Wang, J.

    2016-06-01

    We report the investigation on the ferroelectricity and tunneling electroresistance (TER) effect in PbTiO3 (PTO)-based ferroelectric tunnel junctions (FTJs) using first-principles calculations. For symmetric FTJs, we have calculated the average polarizations of PTO film and effective screening lengths of different metal electrodes for a number of FTJs, which is useful for experimental research. For asymmetric FTJs, significant asymmetric ferroelectric displacements in PTO film are observed, which is attributed to the intrinsic field generated by the two dissimilar electrodes. Moreover, by performing quantum transport calculations on those asymmetric FTJs, a sizable TER effect is observed. It is found that the asymmetry of ferroelectric displacements in PTO barrier, which is determined by the difference of work functions of the electrodes, controls the observed TER effect. Our results will help unravel the TER mechanism of asymmetric FTJs in most experiments and will be useful for the designing of FTJ-based devices.

  4. The effect of temperature on the asymmetrical charge movement in squid giant axons.

    PubMed Central

    Kimura, J E; Meves, H

    1979-01-01

    1. Asymmetrical displacement currents ('gating currents') have been recorded in intracellularly perfused squid giant axons by averaging the currents associated with depolarizing and hyperpolarizing voltage pulses. The effect of temperature on 'gating currents' was studied and compared with the effect of temperature on Na currents. 2. Increasing the temperature in seven steps from 0 to 15 degrees C increased the area under the on- and off-response (Qon, Qoff). The average Q10 values for Qon and Qoff (measured with depolarizing pulses to 0 to 20 mV) were 1.41 and 1.62, respectively. 3. The on- and the off-response were described mathematically by the sum of two exponentials. The first component of the on-response, Qon 1, represented 80% or more of the total charge movement associated with 2.5 msec pulses; the Q10 of Qon 1 was similar to that of total Qon. The first component of the off-response, Qoff 1, represented 50--70% of total Qoff; its Q10 was smaller than that of total Qoff. 4. The temperature dependence of the rate constants (tauon 1)-1 and (tauoff 1)-1 was stronger at temperatures below 6--8 degrees C (Q10 = 3.1--6.4) than at higher temperatures (Q10 = 2.0--3.3). In an Arrhenius plot two lines of different slope were required to fit the data. 5. The effect of increasing the temperature on the Q vs. V curve can be described as an increase of Qmax or, alternatively, as a shift of the curve to more negative potentials. 6. Increasing the temperature from 0 to 15 degrees C increased the peak of the Na current (recorded in sea water with a fifth of the normal Na concentration), increased the rate constants taum-1 and tauh-1 and shifted the m3infinity and hinfinity curves to more positive potentials. 7. The Q10 of the rate constant taum-1 varied between 2.04 and 2.61 and was independent of temperature. In an Arrhenius plot the values for taum-1 could be fitted by a single line. 8. The results support the view that 'gating current' does not simply reflect changes of

  5. Effect of coagulant bath on the gas permeation properties of cellulose acetate asymmetric membrane

    NASA Astrophysics Data System (ADS)

    Mohamed, F.; Hasbullah, H.; Jami'an, W. N. R.; Salleh, W. N. H. W.; Ibrahim, N.; Ali, R. R.

    2016-06-01

    Membrane based gas separation process technology has been recognized as one of the most efficient and advanced unit operation for gas separation. One of the problems in membrane gas separation is membrane performance. This paper explores the application of cellulose acetate (CA) membrane for natural gas purification and separation by improving its permeability and selectivity. The main interest in this research is to study the effect of quench medium on the gas separation performance towards its physical characteristics and gas separation performance of CA membrane. Cellulose acetate polymer was dissolved in n- methyl-2-pyrrolidone solvent and casted onto a glass plate using a pneumatically controlled casting system with fixed shear rate and solvent evaporation times. The parameter varied was the non-solvent used as quench medium during membrane post treatment that were methanol and n-hexane. The different quench media as post treatment affected the O2 and N2 gas permeation and O2/N2 selectivity as well as the tensile strength of the flat sheet asymmetric membrane. Combination of methanol and n-hexane as quench media gave the best result than the other steps. This solvent exchange step influenced the morphology by producing thin skin layer and thus gives better gas separation performance than other steps

  6. Asymmetric airflow and vibration induced by the Coanda effect in a symmetric model of the vocal folds.

    PubMed

    Tao, Chao; Zhang, Yu; Hottinger, Daniel G; Jiang, Jack J

    2007-10-01

    A model constructed from Navier-Stokes equations and a two-mass vocal fold description is proposed in this study. The composite model not only has the capability to describe the aerodynamics in a vibratory glottis but also can be used to study the vocal fold vibration under the driving of the complex airflow in the glottis. Numerical simulations show that this model can predict self-oscillations of the coupled glottal aerodynamics and vocal fold system. The Coanda effect could occur in the vibratory glottis even though the vocal folds have left-right symmetric prephonatory shape and tissue properties. The Coanda effect causes the asymmetric flow in the glottis and the difference in the driving force on the left and right vocal folds. The different pressures applied to the left and right vocal folds induce their displacement asymmetry. By using various lung pressures (0.6-2.0 kPa) to drive the composite model, it was found that the asymmetry of the vocal fold displacement is increased from 1.87% to 11.2%. These simulation results provide numerical evidence for the presence of asymmetric flow in the vibratory glottis; moreover, they indicate that glottal aerodynamics is an important factor in inducing the asymmetric vibration of the vocal folds. PMID:17902863

  7. Examining the asymmetrical effects of goal faultlines in groups: a categorization-elaboration approach.

    PubMed

    Ellis, Aleksander P J; Mai, Ke Michael; Christian, Jessica Siegel

    2013-11-01

    The purpose of this study was to use the categorization-elaboration model (CEM) to examine the asymmetrical effects of goal faultlines in groups, which are present when hypothetical dividing lines are created on the basis of different performance goals, splitting the group into subgroups. On the basis of the CEM, we expected groups with goal faultlines to exhibit higher levels of creative task performance than (a) groups with specific, difficult goals and (b) groups with do-your-best goals. We expected the benefits of goal faultlines to be due to increases in reflective reframing, which occurs when group members build on each other's ideas by shifting to alternate frames. However, we expected groups with goal faultlines to exhibit lower levels of routine task performance than (a) groups with do-your-best goals and (b) groups with specific, difficult goals, due to increased perceptions of loafing. Results from 87 groups generally supported our hypothesized model. Implications are discussed as well as possible limitations and directions for future research. PMID:23855916

  8. How dieting makes some fatter: from a perspective of human body composition autoregulation.

    PubMed

    Dulloo, Abdul G; Jacquet, Jean; Montani, Jean-Pierre

    2012-08-01

    Dieting makes you fat - the title of a book published in 1983 - embodies the notion that dieting to control body weight predisposes the individual to acquire even more body fat. While this notion is controversial, its debate underscores the large gap that exists in our understanding of basic physiological laws that govern the regulation of human body composition. A striking example is the key role attributed to adipokines as feedback signals between adipose tissue depletion and compensatory increases in food intake. Yet, the relative importance of fat depletion per se as a determinant of post-dieting hyperphagia is unknown. On the other hand, the question of whether the depletion of lean tissues can provide feedback signals on the hunger-appetite drive is rarely invoked, despite evidence that food intake during growth is dominated by the impetus for lean tissue deposition, amidst proposals for the existence of protein-static mechanisms for the regulation of growth and maintenance of lean body mass. In fact, a feedback loop between fat depletion and food intake cannot explain why human subjects recovering from starvation continue to overeat well after body fat has been restored to pre-starvation values, thereby contributing to 'fat overshooting'. In addressing the plausibility and mechanistic basis by which dieting may predispose to increased fatness, this paper integrates the results derived from re-analysis of classic longitudinal studies of human starvation and refeeding. These suggest that feedback signals from both fat and lean tissues contribute to recovering body weight through effects on energy intake and thermogenesis, and that a faster rate of fat recovery relative to lean tissue recovery is a central outcome of body composition autoregulation that drives fat overshooting. A main implication of these findings is that the risk of becoming fatter in response to dieting is greater in lean than in obese individuals. PMID:22475574

  9. Gibbs-Tolman approach to the curved interface effects in asymmetric nuclei

    NASA Astrophysics Data System (ADS)

    Kolomietz, V. M.; Sanzhur, A. I.

    2013-10-01

    We redefine the surface tension coefficient and the surface symmetry energy for an asymmetric nuclear Fermi-liquid drop with a finite diffuse layer. Considering a two-component charged Fermi-liquid drop and following the Gibbs-Tolman concept, we introduce the equimolar radius Re of a sharp-surface droplet at which the surface tension is applied and the radius of the tension surface Rs (Laplace radius) which provides the minimum of the surface tension coefficient σ. We have shown that the nuclear Tolman length ξ is negative and the modulus of ξ grows quadratically with the asymmetry parameter X=(N-Z)/(N+Z).

  10. Ion size effects on the osmotic pressure and electrocapillarity in a nanoslit: Symmetric and asymmetric ion sizes

    NASA Astrophysics Data System (ADS)

    Rajni; Oh, J. M.; Kang, I. S.

    2016-06-01

    We analyze the effect of asymmetric finite ion size in nanoconfinement in the view of osmotic pressure and electrocapillarity. When the confinement width becomes comparable with the Debye length, the overlapped electric double layer is significantly deformed by the steric effects. We derive the osmotic pressure from the modified Poisson-Boltzmann equation in a nanoslit to examine the deviation from the ideal osmotic pressure and the repulsive force on the wall considering the asymmetry of ion sizes. Then the electrocapillarity due to the steric effect is investigated under constant potential condition with the flat interface assumption. Later, the deformation by the electrocapillarity is also considered in the first order approximation.

  11. Ion size effects on the osmotic pressure and electrocapillarity in a nanoslit: Symmetric and asymmetric ion sizes.

    PubMed

    Rajni; Oh, J M; Kang, I S

    2016-06-01

    We analyze the effect of asymmetric finite ion size in nanoconfinement in the view of osmotic pressure and electrocapillarity. When the confinement width becomes comparable with the Debye length, the overlapped electric double layer is significantly deformed by the steric effects. We derive the osmotic pressure from the modified Poisson-Boltzmann equation in a nanoslit to examine the deviation from the ideal osmotic pressure and the repulsive force on the wall considering the asymmetry of ion sizes. Then the electrocapillarity due to the steric effect is investigated under constant potential condition with the flat interface assumption. Later, the deformation by the electrocapillarity is also considered in the first order approximation. PMID:27415363

  12. Improving the field-effect performance of Bi2S3 single nanowires by an asymmetric device fabrication.

    PubMed

    Lu, Fangyuan; Li, Renxiong; Li, Yan; Huo, Nengjie; Yang, Juehan; Li, Yongtao; Li, Bo; Yang, Shengxue; Wei, Zhongming; Li, Jingbo

    2015-01-12

    High-quality Bi2 S3 nanowires are synthesized by chemical vapor deposition and their intrinsic photoresponsive and field-effect characteristics are explored in detail. Among the studied Au-Au, Ag-Ag, and Au-Ag electrode pairs, the device with stepwise band alignment of asymmetric Au-Ag electrodes has the highest mobility. Furthermore, it is shown that light can cause a sevenfold decrease of the on/off ratio. This can be explained by the photoexcited charge carriers that are more beneficial to the increase of Ioff than Ion . The photoresponsive properties of the asymmetric Au-Ag electrode devices were also explored, and the results show a photoconductive gain of seven with a rise time of 2.9 s and a decay time of 1.6 s. PMID:25294685

  13. Exploring the effects of seated whole body vibration exposure on repetitive asymmetric lifting tasks.

    PubMed

    Mehta, Jay P; Lavender, Steven A; Jagacinski, Richard J; Sommerich, Carolyn M

    2015-01-01

    This study investigated changes in the physiological and behavioral responses to repetitive asymmetric lifting activity after exposure to whole body vibrations. Seventeen healthy volunteers repeatedly lifted a box (15% of lifter's capacity) positioned in front of them at ankle level to a location on their left side at waist level at the rate of 10 lifts/min for a period of 60 minutes. Prior to lifting, participants were seated on a vibrating platform for 60 minutes; in one of the two sessions the platform did not vibrate. Overall, the physiological responses assessed using near-infrared spectroscopy signals for the erector spinae muscles decreased significantly over time during the seating and the lifting tasks (p < 0.001). During repetitive asymmetric lifting, behavioral changes included increases in peak forward bending motion, twisting movement, and three-dimensional movement velocities of the spine. The lateral bending movement of the spine and the duration of each lift decreased significantly over the 60 minutes of repetitive lifting. With exposure to whole body vibration, participants twisted farther (p = 0.046) and twisted faster (p = 0.025). These behavioral changes would suggest an increase in back injury risk when repetitive lifting tasks are preceded by whole body vibration exposure. PMID:25264920

  14. Effects of asymmetric cultural experiences on the auditory pathway: evidence from music.

    PubMed

    Wong, Patrick C M; Perrachione, Tyler K; Margulis, Elizabeth Hellmuth

    2009-07-01

    Cultural experiences come in many different forms, such as immersion in a particular linguistic community, exposure to faces of people with different racial backgrounds, or repeated encounters with music of a particular tradition. In most circumstances, these cultural experiences are asymmetric, meaning one type of experience occurs more frequently than other types (e.g., a person raised in India will likely encounter the Indian todi scale more so than a Westerner). In this paper, we will discuss recent findings from our laboratories that reveal the impact of short- and long-term asymmetric musical experiences on how the nervous system responds to complex sounds. We will discuss experiments examining how musical experience may facilitate the learning of a tone language, how musicians develop neural circuitries that are sensitive to musical melodies played on their instrument of expertise, and how even everyday listeners who have little formal training are particularly sensitive to music of their own culture(s). An understanding of these cultural asymmetries is useful in formulating a more comprehensive model of auditory perceptual expertise that considers how experiences shape auditory skill levels. Such a model has the potential to aid in the development of rehabilitation programs for the efficacious treatment of neurologic impairments. PMID:19673772

  15. Effects of nose bluntness, roughness, and surface perturbations on the asymmetric flow past slender bodies at large angles of attack

    NASA Technical Reports Server (NTRS)

    Moskovitz, Cary A.; Dejarnette, F. R.; Hall, Robert M.

    1989-01-01

    The effects of such geometric perturbations as variations of model-tip sharpness and roughness, as well as discrete surface perturbations, on the asymmetric flow past slender bodies is experimentally investigated for the cases of a cone/cylinder model having a 10-deg semiapex angle and a 3.0-caliber tangent ogive model. Both models have base diameters of 3.5 inches, and were tested in laminar flow conditions at angles-of-attack in the 30-60 deg range. Single, discrete roughness elements were represented by beads; bead effectiveness was judged on the basis of the extent to which they affected the flowfield in various conditions.

  16. The Effect of Asymmetric Mechanical and Thermal Loading on Membrane Wrinkling

    NASA Technical Reports Server (NTRS)

    Blandino, Joseph R.; Johnston, John D.; Miles, Jonathan J.; Dharamsi, Urmil K.; Brodeur, Stephen J. (Technical Monitor)

    2002-01-01

    Large, tensioned membranes are being considered for future gossamer spacecraft systems. Examples include sunshields, solar sails, and membrane optics. In many. cases a relatively flat membrane with minimal wrinkling is desired. Developing methods to predict and measure membrane wrinkling is important to the future development of gossamer spacecraft. Numerical and experimental data are presented for a 0.5 m square, tensioned membrane. The membrane is subjected to symmetric and asymmetric mechanical loading. Data are also presented for a symmetrically loaded membrane subjected to spot heating in the center. The numerical model shows good agreement with the experiment for wrinkle angle data. There is. also reasonable agreement for the wrinkled area for both isothermal and elevated temperature tests.

  17. Asymmetric effect of automatic deviant detection: The effect of familiarity in visual mismatch negativity.

    PubMed

    Sulykos, István; Kecskés-Kovács, Krisztina; Czigler, István

    2015-11-11

    The visual mismatch negativity (vMMN) component is regarded as a prediction error signal elicited by events violating the sequential regularities of environmental stimulation. The aim of the study was to investigate the effect of familiarity on the vMMN. Stimuli were patterns comprised of familiar (N) or unfamiliar (И) letters. In a passive oddball paradigm, letters (N and И) were presented as either standard or deviant in separate conditions. VMMNs emerged in both conditions; peak latency of vMMN was shorter to the И deviant compared to the vMMN elicited by the N deviant. To test the orientation-specific effect of the oblique lines on the vMMN, we introduced a control experiment. In the control experiment, the patterns were constructed solely from oblique lines, identical to the oblique lines of the N and И stimuli. Contrary to the first experiment, there was no significant difference between the vMNNs elicited by the two orientations. Therefore, the differences in vMMNs to И and N deviants are not attributable to the physical difference between the И and N stimuli. Consequently, the vMMN is sensitive to the familiarity of the stimuli. This article is part of a Special Issue entitled SI: Prediction and Attention. PMID:25724142

  18. The effect of asymmetric heating on flow stability and heat transfer for flow in a vertical tube

    SciTech Connect

    Tappan, C.H.

    1987-11-01

    This study presents experimental results of combined free and forced convection heat transfer in a vertical tube with a circumferentially nonuniform constant wall heat flux. The effect of an asymmetric wall heat flux on flow stability and on the rate of heat transfer for water flowing downward in a vertical tube was investigated. Experimental results were used to develop two stability maps which identify various flow regimes, corresponding to different thermal and hydraulic conditions. Heat transfer coefficients were also determined. Experimental results in the present investigation were compared to those with uniform heating in horizontal and vertical tube flow situations discussed in the literature. 23 refs., 12 figs., 1 tab.

  19. Diverse interface effects on ferroelectricity and magnetoelectric coupling in asymmetric multiferroic tunnel junctions: the role of the interfacial bonding structure.

    PubMed

    Liu, X T; Chen, W J; Jiang, G L; Wang, B; Zheng, Yue

    2016-01-28

    Interface and size effects on electric/magnetic orders and magnetoelectric coupling are vital in the modern application of quantum-size functional devices based on multiferroic tunnel junctions. In order to give a comprehensive study of the interface and size effects, the properties of a typical asymmetric multiferroic tunnel junction, i.e., Fe/BaTiO3/Co, have been calculated using the first-principles simulations. Most importantly, all of the eight possible structures with four combinations of electrode/ferroelectric interfaces (i.e., Fe/BaO, Fe/TiO2, Co/BaO and Co/TiO2) and a series of barrier thicknesses have been taken into account. In this work, the equilibrium configurations, polarization, charge density, spin density and magnetic moments, etc., have been completely simulated and comprehensively analyzed. It is found that the ferroelectric stability is determined as a competition outcome of the strength of short-range chemical bondings and long-range depolarization/built-in fields. M/BaO (M = magnetic metal) terminations show an extraordinary enhancement of local polarization near the interface and increase the critical thickness of ferroelectricity. The bistability of polarization is well kept at the M/TiO2 interface. At the same time, the induced magnetic moment on atoms at the interfaces is rather localized and dominated by the local interfacial configuration. Reversing electric polarization can switch the induced magnetic moments, wherein atoms in M-O-Ti and M-Ti-O chains show preference for being magnetized. In addition, the difference between the sum of the interfacial magnetic moments is also enlarged with the increase of the barrier thickness. Our study provides a comprehensive and detailed reference to the manipulation and utilization of the interface, size and magnetoelectric effects in asymmetric multiferroic tunnel junctions. PMID:26732894

  20. The effects of moist convection on the tropospheric response to tropical and subtropical zonally-asymmetric torques

    NASA Astrophysics Data System (ADS)

    Boos, W. R.; Shaw, T. A.

    2011-12-01

    Tropospheric winds can be altered by vertical transfers of momentum caused by orographic gravity waves and convection, both of which tend to be highly localized in space. We showed in separate work that such zonally-asymmetric torques produce a characteristic response in dry models, with a pattern of tropical ascent that is qualitatively well-described by linear dynamics and a meridional shift of the eddy-driven mid-latitude jet. Here we use several idealized models to examine the effects of moisture on the tropospheric response to zonally-asymmetric torques. While the dynamical response to an upper-tropospheric toque in moist models can have a spatial structure that is qualitatively similar to that in dry models, moisture introduces several important modifications. One of the most dramatic of these is an amplification of the vertical velocity by nearly an order of magnitude in moist models. This occurs in a general circulation model with parameterized moist convection and an entirely oceanic lower boundary, and also in a quasi-linear model of the troposphere's first-baroclinic mode. The amplification is shown to result from the reduced effective static stability of a moist atmosphere, and can thus be rectified by the distribution of precipitation in the basic state. Given this amplification of the irrotational part of the response, we show how the vorticity budget necessitates changes in the horizontal structure of the nondivergent flow. The intensity and horizontal structure of the response in moist models can also be greatly altered by wind-induced surface heat exchange (WISHE), with enhanced zonal winds increasing ocean evaporation and convectively-coupled ascent. We briefly discuss some possible implications of these results for the effect of vertical momentum transfers on regional precipitation.

  1. Exploring perception-action relations in music production: The asymmetric effect of tonal class.

    PubMed

    Jebb, Andrew T; Pfordresher, Peter Q

    2016-05-01

    When playing musical passages, performers integrate the pitch content of auditory feedback with current action plans. However, this process depends on the degree to which the musical structure of the feedback melody is perceived as similar to the structure of what is planned. Four experiments reported here explored the relationship between the tonal class of planned melodies (tonal or atonal) and the sequence of events formed by auditory feedback. Participants produced short melodies from memory that were either tonal (Experiments 1 and 3) or atonal (Experiments 2 and 4). Auditory feedback matched the planned melody with respect to contour but could vary in tonal class. The results showed that when participants planned a tonal melody, atonal feedback was treated as unrelated to the planned sequence. However, when planning an atonal melody, tonal feedback was still treated as similar to the planned sequence. This asymmetric similarity mirrors findings found within the music perception literature and implies that schematic musical knowledge is highly active in determining perception-action relations during music performance. PMID:26594878

  2. Effects of benzo-annelation of asymmetric phthalocyanine on the photovoltaic performance of dye-sensitized solar cells.

    PubMed

    Yu, Lijuan; Shi, Wenye; Lin, Li; Liu, Yuwen; Li, Renjie; Peng, Tianyou; Li, Xingguo

    2014-06-14

    Novel highly asymmetric zinc tetraazaporphyrin (TAP) derivatives (Zn-tri-TAPNc and Zn-tri-PcNc) with one carboxyl and three tert-butyl peripheral substituent groups were synthesized. A highly asymmetric zinc phthalocyanine (ZnPc) derivative (Zn-tri-PcNc) has a benzo-annelated ring which contains tribenzonaphtho-condensed tetraazaporphyrin with the same peripheral substituents as Zn-tri-TAPNc. As a sensitizer for the TiO2-based dye-sensitized solar cell, Zn-tri-PcNc derived from the benzo-annelation of the TAP macrocycle showed improved light harvesting and electron injection efficiency, which can retard the charge recombination, resulting in a great improvement in the incident photon-to-current conversion efficiency (IPCE). The Zn-tri-PcNc-sensitized solar cell exhibited a higher conversion efficiency (2.89%) than the Zn-tri-TAPNc-sensitized one (1.20%) under AM 1.5G solar irradiation. The present results on the TAP macrocycle's benzo-annelation demonstrate that optimization of molecular structure via changing the peripheral substituent group's "push-pull" effect and enlarging the conjugated π-system is an effective approach to improve the performance of the tetraazaporphyrin-based dye-sensitized solar cell. PMID:24740460

  3. Intense laser effects on the optical properties of asymmetric GaAs double quantum dots under applied electric field

    NASA Astrophysics Data System (ADS)

    Bejan, Doina; Niculescu, Ecaterina Cornelia

    2016-06-01

    We investigated the combined effects of a non-resonant intense laser field and a static electric field on the electronic structure and the nonlinear optical properties (absorption, optical rectification) of a GaAs asymmetric double quantum dot under a strong probe field excitation. The calculations were performed within the compact density-matrix formalism under steady state conditions using the effective mass approximation. Our results show that: (i) the electronic structure and optical properties are sensitive to the dressed potential; (ii) under applied electric fields, an increase of the laser intensity induces a redshift of the optical absorption and rectification spectra; (iii) the augment of the electric field strength leads to a blueshift of the spectra; (iv) for high electric fields the optical spectra show a shoulder-like feature, related with the occurrence of an anti-crossing between the two first excited levels.

  4. Effect of thienyl groups on the photoisomerization and rotamerism of symmetric and asymmetric diaryl-ethenes and diaryl-butadienes.

    PubMed

    Bartocci, Giampiero; Galiazzo, Guido; Ginocchietti, Gabriella; Mazzucato, Ugo; Spalletti, Anna

    2004-09-01

    Five symmetric (bis-substituted) and asymmetric (mono-substituted) analogues of E-stilbene and EE-1,4-diphenylbutadiene, where one or both the side aryls are 2'-thienyl or 3'-thienyl groups, have been studied by stationary and pulsed fluorimetric techniques, laser flash photolysis, conventional photochemical methods and theoretical calculations. The results obtained for these compounds and the comparison with those previously reported for three other compounds of the same series, allowed the effects of the position of the heteroatom and of the extension of the olefin chain on the excited state relaxation properties to be understood. The presence of one or two thienyl groups and their positional isomerism affect the spectral behaviour, the relaxation properties (radiative/reactive competition), the photoisomerization mechanism (singlet/triplet) and the ground state rotamerism. For the dienes containing the 3'-thienyl substituent(s), two rotamers were evidenced whose radiative and photochemical properties were obtained by selective excitation. PMID:15346189

  5. Carrier envelope phase effect on the spatial distribution of high-order harmonic generation in asymmetric molecule

    NASA Astrophysics Data System (ADS)

    Jun, Zhang; Hai-Feng, Liu; Xue-Fei, Pan; Hui, Du; Jing, Guo; Xue-Shen, Liu

    2016-05-01

    The spatial distribution in high-order harmonic generation (HHG) from the asymmetric diatomic molecule HeH2+ is investigated by numerically solving the non-Born–Oppenheimer time-dependent Schrödinger equation (TDSE). The spatial distribution of the HHG spectra shows that there is little contribution in HHG around the geometric center of two nuclei (z = 1.17 a.u.) and the equilibrium internuclear position of the H nucleus (z = 3.11 a.u.). We demonstrate the carrier envelope phase (CEP) effect on the spatial distribution of HHG in a few-cycle laser pulse. The HHG process is investigated by the time evolution of the electronic density distribution. The time–frequency analysis of HHG from two nuclei in HeH2+ is presented to further explain the underlying physical mechanism. Project supported by the National Natural Science Foundation of China (Grant Nos. 11271158, 11574117, and 61575077).

  6. Mini-ISES identifies promising carbafructopyranose-based salens for asymmetric catalysis: Tuning ligand shape via the anomeric effect

    PubMed Central

    Karukurichi, Kannan R.; Fei, Xiang; Swyka, Robert A.; Broussy, Sylvain; Shen, Weijun; Dey, Sangeeta; Roy, Sandip K.; Berkowitz, David B.

    2015-01-01

    This study introduces new methods of screening for and tuning chiral space and in so doing identifies a promising set of chiral ligands for asymmetric synthesis. The carbafructopyranosyl-1,2-diamine(s) and salens constructed therefrom are particularly compelling. It is shown that by removing the native anomeric effect in this ligand family, one can tune chiral ligand shape and improve chiral bias. This concept is demonstrated by a combination of (i) x-ray crystallographic structure determination, (ii) assessment of catalytic performance, and (iii) consideration of the anomeric effect and its underlying dipolar basis. The title ligands were identified by a new mini version of the in situ enzymatic screening (ISES) procedure through which catalyst-ligand combinations are screened in parallel, and information on relative rate and enantioselectivity is obtained in real time, without the need to quench reactions or draw aliquots. Mini-ISES brings the technique into the nanomole regime (200 to 350 nmol catalyst/20 μl organic volume) commensurate with emerging trends in reaction development/process chemistry. The best-performing β-d-carbafructopyranosyl-1,2-diamine–derived salen ligand discovered here outperforms the best known organometallic and enzymatic catalysts for the hydrolytic kinetic resolution of 3-phenylpropylene oxide, one of several substrates examined for which the ligand is “matched.” This ligand scaffold defines a new swath of chiral space, and anomeric effect tunability defines a new concept in shaping that chiral space. Both this ligand set and the anomeric shape-tuning concept are expected to find broad application, given the value of chiral 1,2-diamines and salens constructed from these in asymmetric catalysis. PMID:26501130

  7. Asymmetric drag in oscillatory motion: ratchet effect without an asymmetric potential.

    PubMed

    Fomin, Vladimir M; Smith, Elliot J; Karnaushenko, Dmitriy D; Makarov, Denys; Schmidt, Oliver G

    2013-05-01

    Asymmetry of magnetic objects in a fluid under an oscillating magnetic field leads to a wealth of nonequilibrium dynamics phenomena including a novel ratchet effect without an asymmetric substrate. These nonlinear dynamics are explained in the framework of the Stokes' model by a drag coefficient, which depends on the direction of motion. This approach is general and is independent of the physical mechanism responsible for this directional dependence of the drag coefficient as well as the size of the object. The theoretical model is experimentally verified for two systems, a nonrigid magnetic microcoil and a chiral magnetic macroobject immersed in a bounded fluid. PMID:23767502

  8. On the Interactive-beating-modes Model: Generation of Asymmetric Multiplet Structures and Explanation of the Blazhko Effect

    NASA Astrophysics Data System (ADS)

    Bryant, Paul H.

    2016-02-01

    This paper considers a nonlinear coupling between a radial and a nonradial mode of nearly the same frequency. The results may be of general interest, but in particular have application to the “beating-modes model” of the Blazhko effect which was recently shown to accurately reproduce the light curve of RR Lyr. For weak coupling, the two modes do not phase-lock and they retain separate frequencies, but the coupling nevertheless has important consequences. Upon increasing the coupling strength from zero, an additional side-peak emerges in the spectrum forming an asymmetric triplet centered on the fundamental. As the coupling is further increased, the amplitude of this side-peak increases and the three peaks are also pulled toward each other, decreasing the Blazhko frequency. Beyond a critical coupling strength, phase-locking occurs between the modes. With appropriate choice of coupling strength, this “interactive beating-modes model” can match the side-peak amplitude ratio of any star. The effects of nonlinear damping are also explored and found to generate additional side-peaks of odd order. Consistent with this, the odd side-peaks are found to be favored in V808 Cyg. It is also shown that the Blazhko effect generates a fluctuating “environment” that can have a modulatory effect on other excited modes of the star. An example is found in V808 Cyg where the modulation is at double the Blazhko frequency. An explanation is found for this mysterious doubling, providing additional evidence in favor of the model.

  9. A Guided Wave Sensor Based on the Inverse Magnetostrictive Effect for Distinguishing Symmetric from Asymmetric Features in Pipes

    PubMed Central

    Xu, Jiang; Wu, Xinjun; Kong, Dongying; Sun, Pengfei

    2015-01-01

    The magnetostrictive guided wave sensor with a single induced winding cannot distinguish axially symmetric from non-axially symmetric features in a pipe, because it is impossible for the sensor to detect the non-axially symmetric mode waves. When we study the effect of the change of the magnetic field in the air zone for receiving the longitudinal guided wave mode, we find that the change of the magnetic flux in the air zone is almost equivalent to the change of the flux in the pipe wall, but in opposite directions. Based on this phenomenon, we present a sensor that can detect the flexural-mode waves in pipes based on the inverse magnetostrictive effect. The sensor is composed of several coils that are arranged evenly on the outside of pipes. The coils induce a change in magnetic flux in the air to detect the flexural-mode waves. The waves can be determined by adding a phase delay to the induced signals. The symmetric and asymmetric features of a pipe can be distinguished using the sensor. A prototype sensor that can detect F(1,3) and F(2,3) mode waves is presented. The function of the sensor is verified by experiments. PMID:25738769

  10. The Effect of Suppression of Vortex Generator Jets with Asymmetric Orifices on Flow Separation

    NASA Astrophysics Data System (ADS)

    Hasegawa, Hiroaki; Hayashi, Naoki

    In vortex generator jets (VGJs), the beneficial effect of separation control is obtained only if the jets are pitched to the lower wall and skewed with respect to the freestream direction. In particular, in the case of VGJs with circular orifices, the jets are pitched at an angle of 45 deg or less to the wall to achieve effective suppression, due to the generation of strong dominant vortices. On the other hand, it was confirmed that the vortices for the VGJs with the rectangular orifices are stronger and appear to provide more effective momentum transfer across the wall boundary layer, in contrast to the vortices for the VGJs with circular orifices in the previous study. In the present study, the suppression effect is investigated for VGJs with T-shaped orifices combined into two rectangular orifices in the case of a large pitch angle (60 deg). The VGJs with T-shaped orifices were practically applied to the flow separation control of a two-dimensional diffuser, and the suppression effect for the T-shaped orifices was compared to that for the circular orifices. The behavior and the decay of longitudinal vortices in the downstream direction are also described. The T-shaped orifices produce a counter-rotating vortex pair that has different strengths between positive and negative vortices, and longitudinal vortices exist near the lower wall. Therefore, the VGJs with T-shaped orifices provide more effective momentum transfer to the boundary layer and make the separation control effective, in contrast to the VGJs with circular orifices. The formation and behavior of the counter-rotating vortex pair produced by the interaction of the jets and the freestream in the downstream direction were strongly affected by the jet orifice shape.

  11. Asymmetric impact of the physiological effect of carbon dioxide on hydrological responses to instantaneous negative and positive CO2 forcing

    NASA Astrophysics Data System (ADS)

    Abe, Manabu; Shiogama, Hideo; Yokohata, Tokuta; Emori, Seita; Nozawa, Toru

    2015-10-01

    We conducted sensitivity experiments using a coupled atmosphere-ocean general circulation model to examine the asymmetry between the hydrological responses to instantaneous positive and negative CO2 forcing and the impact of the CO2 physiological effects (CDPEs) on these responses. This study focuses on the fast response occurring on time scales shorter than 1 year after imposing CO2 forcing. Experiments investigating the CO2 physiological effect show that the fast response of precipitation to positive CO2 forcing is a decrease in the global and annual mean, whereas that of negative forcing is an increase the global and annual mean precipitation. The fast global precipitation response to negative forcing is stronger than the response to positive forcing. In contrast, the experiments without the CDPE reveal similar magnitudes of the fast global precipitation responses to negative and positive CO2 forcing. Significant differences in the magnitudes of the fast precipitation response due to the CDPE are found in tropical regions such as the Amazon Basin, the Maritime Continents, and tropical Africa, where C3-type plants are common. The stomatal conductance of plant leaves is decreased by both positive and negative CO2 forcing, which suppress the transpiration from the leaves. Consequently, the CDPE enhances the asymmetry of the fast precipitation responses to positive and negative CO2 forcing. The asymmetric impact of CDPE requires a careful evaluation of future hydrological changes which is constrained by paleoclimate evidence.

  12. Effects of Ground Equalization on the Electrical Performance of Asymmetric CPW Shunt Stubs

    NASA Technical Reports Server (NTRS)

    Dib, Nihad; Gupta, Minoo; Ponchak, George; Katehi, Linda

    1993-01-01

    A hybrid technique is used to study the effects of ground equalization on the electrical performance of CPW shunt stubs. Extensive experiments have been performed and the results are in good agreement with theoretical data. The advantages of using air-bridges in CPW circuits as opposed to bond-wires are also discussed.

  13. Asymmetric effect on single-file dense pedestrian flow

    NASA Astrophysics Data System (ADS)

    Kuang, Hua; Cai, Mei-Jing; Li, Xing-Li; Song, Tao

    2015-11-01

    In this paper, an extended optimal velocity model is proposed to simulate single-file dense pedestrian flow by considering asymmetric interaction (i.e. attractive force and repulsive force), which depends on the different distances between pedestrians. The stability condition of this model is obtained by using the linear stability theory. The phase diagram comparison and analysis show that asymmetric effect plays an important role in strengthening the stabilization of system. The modified Korteweg-de Vries (mKdV) equation near the critical point is derived by applying the reductive perturbation method. The pedestrian jam could be described by the kink-antikink soliton solution for the mKdV equation. From the simulation of space-time evolution of the pedestrians distance, it can be found that the asymmetric interaction is more efficient compared to the symmetric interaction in suppressing the pedestrian jam. Furthermore, the simulation results are consistent with the theoretical analysis as well as reproduce experimental phenomena better.

  14. Asymmetric effects on the optical properties of double-quantum well systems

    NASA Astrophysics Data System (ADS)

    Silotia, Poonam; Batra, Kriti; Prasad, Vinod

    2014-02-01

    Linear, nonlinear, and total absorption coefficient and refractive index changes of double-quantum well (DQW) systems are studied theoretically in the presence of external static electric field applied along the growth direction. The analytical expression for the linear and nonlinear optical properties is obtained using density matrix method. Emphasis is laid on the effect of asymmetry in the shapes of DQW system on optical properties. Some interesting results are obtained and explained.

  15. Effects of Noise on Asymmetric Bidirectional Controlled Teleportation

    NASA Astrophysics Data System (ADS)

    Nie, Yi-you; Sang, Ming-huang

    2016-07-01

    We present a scheme for asymmetric bidirectional controlled teleportation via a six-qubit cluster state in noisy environments, which includes the phase-damping and amplitude-damping channels. We analytically derive the fidelities of the asymmetric bidirectional controlled teleportation process in these two noise channels. We show that the fidelities only depend on the initial state and the noisy rate.

  16. The electrical asymmetry effect in geometrically asymmetric capacitive radio frequency plasmas

    NASA Astrophysics Data System (ADS)

    Schüngel, E.; Eremin, D.; Schulze, J.; Mussenbrock, T.; Czarnetzki, U.

    2012-09-01

    The electrical asymmetry effect (EAE) allows an almost ideal separate control of the mean ion energy, , and flux, Γi, at the electrodes in capacitive radio frequency discharges with identical electrode areas driven at two consecutive harmonics with adjustable phase shift, θ. In such geometrically symmetric discharges, a DC self bias is generated as a function of θ. Consequently, can be controlled separately from Γi by adjusting the phase shift. Here, we systematically study the EAE in low pressure dual-frequency discharges with different electrode areas operated in argon at 13.56 MHz and 27.12 MHz by experiments, kinetic simulations, and analytical modeling. We find that the functional dependence of the DC self bias on θ is similar, but its absolute value is strongly affected by the electrode area ratio. Consequently, the ion energy distributions change and can be controlled by adjusting θ, but its control range is different at both electrodes and determined by the area ratio. Under distinct conditions, the geometric asymmetry can be compensated electrically. In contrast to geometrically symmetric discharges, we find the ratio of the maximum sheath voltages to remain constant as a function of θ at low pressures and Γi to depend on θ at the smaller electrode. These observations are understood by the model. Finally, we study the self-excitation of non-linear plasma series resonance oscillations and its effect on the electron heating.

  17. The electrical asymmetry effect in geometrically asymmetric capacitive radio frequency plasmas

    SciTech Connect

    Schuengel, E.; Schulze, J.; Czarnetzki, U.; Eremin, D.; Mussenbrock, T.

    2012-09-01

    The electrical asymmetry effect (EAE) allows an almost ideal separate control of the mean ion energy, , and flux, {Gamma}{sub i}, at the electrodes in capacitive radio frequency discharges with identical electrode areas driven at two consecutive harmonics with adjustable phase shift, {theta}. In such geometrically symmetric discharges, a DC self bias is generated as a function of {theta}. Consequently, can be controlled separately from {Gamma}{sub i} by adjusting the phase shift. Here, we systematically study the EAE in low pressure dual-frequency discharges with different electrode areas operated in argon at 13.56 MHz and 27.12 MHz by experiments, kinetic simulations, and analytical modeling. We find that the functional dependence of the DC self bias on {theta} is similar, but its absolute value is strongly affected by the electrode area ratio. Consequently, the ion energy distributions change and can be controlled by adjusting {theta}, but its control range is different at both electrodes and determined by the area ratio. Under distinct conditions, the geometric asymmetry can be compensated electrically. In contrast to geometrically symmetric discharges, we find the ratio of the maximum sheath voltages to remain constant as a function of {theta} at low pressures and {Gamma}{sub i} to depend on {theta} at the smaller electrode. These observations are understood by the model. Finally, we study the self-excitation of non-linear plasma series resonance oscillations and its effect on the electron heating.

  18. Effect of asymmetric auxin application on Helianthus hypocotyl curvature

    NASA Technical Reports Server (NTRS)

    Migliaccio, F.; Rayle, D. L.

    1989-01-01

    Indole-3-acetic acid was applied asymmetrically to the hypocotyls of sunflower (Helianthus annuus L.) seedlings. After 5 hours on a clinostat, auxin gradients as small as 1 to 1.3 produced substantial (more than 60 degrees) hypocotyl curvature. This result suggests the asymmetric growth underlying hypocotyl gravitropism can be explained by lateral auxin redistribution.

  19. Asymmetric inhibitory treatment effects in multilingual aphasia

    PubMed Central

    Goral, Mira; Naghibolhosseini, Maryam; Conner, Peggy

    2014-01-01

    Findings from recent psycholinguistic studies of bilingual processing support the hypothesis that both languages of a bilingual are always active and that bilinguals continually engage in processes of language selection. This view aligns with the convergence hypothesis of bilingual language representation (Abutalebi & Green, 2008). Furthermore, it is hypothesized that when bilinguals perform a task in one language they need to inhibit their other, non-target language(s) (e.g., Costa, Miozzo, & Caramazza, 1999) and that stronger inhibition is required when the task is performed in the weaker language than in the stronger one (e.g., Costa & Santesteban, 2004). The study of multilingual individuals who acquire aphasia resulting from a focal brain lesion offers a unique opportunity to test the convergence hypothesis and the inhibition asymmetry. We report on a trilingual person with chronic non-fluent aphasia who at the time of testing demonstrated greater impairment in her first acquired language (Persian) than in her third, later-learned language (English). She received treatment in English followed by treatment in Persian. An examination of her connected language production revealed improvement in her grammatical skills in each language following intervention in that language, but decreased grammatical accuracy in English following treatment in Persian. The increased error rate was evident in structures that are not shared by the two languages (e.g., use of auxiliary verbs). The results support the prediction that greater inhibition is applied to the stronger language than to the weaker language, regardless of their age of acquisition. We interpret the findings as consistent with convergence theories that posit overlapping neuronal representation and simultaneous activation of multiple languages, and with proficiency-dependent asymmetric inhibition in multilinguals. PMID:24499302

  20. Effects on Calculated Half-Widths and Shifts from the Line Coupling for Asymmetric-Top Molecules

    NASA Technical Reports Server (NTRS)

    Ma, Q.; Boulet, C.; Tipping, R. H.

    2014-01-01

    The refinement of the Robert-Bonamy formalism by considering the line coupling for linear molecules developed in our previous studies [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013); 140, 104304 (2014)] have been extended to asymmetric-top molecules. For H2O immersed in N2 bath, the line coupling selection rules applicable for the pure rotational band to determine whether two specified lines are coupled or not are established. Meanwhile, because the coupling strengths are determined by relative importance of off-diagonal matrix elements versus diagonal elements of the operator -iS1 -S2, quantitative tools are developed with which one is able to remove weakly coupled lines from consideration. By applying these tools, we have found that within reasonable tolerances, most of the H2O lines in the pure rotational band are not coupled. This reflects the fact that differences of energy levels of the H2O states are pretty large. But, there are several dozen strongly coupled lines and they can be categorized into different groups such that the line couplings occur only within the same groups. In practice, to identify those strongly coupled lines and to confine them into sub-linespaces are crucial steps in considering the line coupling. We have calculated half-widths and shifts for some groups, including the line coupling. Based on these calculations, one can conclude that for most of the H2O lines, it is unnecessary to consider the line coupling. However, for several dozens of lines, effects on the calculated half-widths from the line coupling are small, but remain noticeable and reductions of calculated half-widths due to including the line coupling could reach to 5%. Meanwhile, effects on the calculated shifts are very significant and variations of calculated shifts could be as large as 25%.

  1. Effects on calculated half-widths and shifts from the line coupling for asymmetric-top molecules

    SciTech Connect

    Ma, Q.; Tipping, R. H.

    2014-06-28

    The refinement of the Robert-Bonamy formalism by considering the line coupling for linear molecules developed in our previous studies [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013); 140, 104304 (2014)] have been extended to asymmetric-top molecules. For H{sub 2}O immersed in N{sub 2} bath, the line coupling selection rules applicable for the pure rotational band to determine whether two specified lines are coupled or not are established. Meanwhile, because the coupling strengths are determined by relative importance of off-diagonal matrix elements versus diagonal elements of the operator −iS{sub 1} − S{sub 2}, quantitative tools are developed with which one is able to remove weakly coupled lines from consideration. By applying these tools, we have found that within reasonable tolerances, most of the H{sub 2}O lines in the pure rotational band are not coupled. This reflects the fact that differences of energy levels of the H{sub 2}O states are pretty large. But, there are several dozen strongly coupled lines and they can be categorized into different groups such that the line couplings occur only within the same groups. In practice, to identify those strongly coupled lines and to confine them into sub-linespaces are crucial steps in considering the line coupling. We have calculated half-widths and shifts for some groups, including the line coupling. Based on these calculations, one can conclude that for most of the H{sub 2}O lines, it is unnecessary to consider the line coupling. However, for several dozens of lines, effects on the calculated half-widths from the line coupling are small, but remain noticeable and reductions of calculated half-widths due to including the line coupling could reach to 5%. Meanwhile, effects on the calculated shifts are very significant and variations of calculated shifts could be as large as 25%.

  2. Strong enhancement of Penning ionization for asymmetric atom pairs in cold Rydberg gases: the Tom and Jerry effect

    NASA Astrophysics Data System (ADS)

    Efimov, D. K.; Miculis, K.; Bezuglov, N. N.; Ekers, A.

    2016-06-01

    We consider Penning ionization of Rydberg atom pairs as an Auger-type process induced by the dipole–dipole interaction and employ semiclassical formulae for dipole transitions to calculate the autoionization width as a function of the principal quantum numbers, n d , n i , of both atoms. While for symmetric atom pairs with {n}d={n}i={n}0 the well-known increase of the autoionization width with increasing n 0 is obtained, the result for asymmetric pairs is counterintuitive—for a fixed n i of the ionizing atom of the pair, the autoionization width strongly increases with decreasing n d of the de-excited atom. For H Rydberg atoms this increase reaches two orders of magnitude at the maximum of the n d dependence, and the same type of counterintuitive behavior is exhibited also by Na, Rb and Cs atoms. This is a purely quantum-mechanical effect, which points towards existence of optimal (we call them ‘Tom’ and ‘Jerry’ for ‘big’ and ‘small’) pairs of Rydberg atoms with respect to autoionization efficiency. Building on the model of population redistribution in cold Rydberg gases proposed in [1], we demonstrate that population evolution following the initial laser excitation of Rydberg atoms in state n 0 would eventually lead to the formation of such Tom–Jerry pairs with {n}i\\gt {n}0\\gt {n}d which feature autoionization widths that are enhanced by several orders of magnitude compared to that of two atoms in the initial laser-excited state n 0. We also show that in the high-density regime of cold Rydberg gas experiments the ionization rate of Tom–Jerry pairs can be substantially larger than the blackbody radiation-induced photoionization rate.

  3. Dual task effects for asymmetric stepping on a split-belt treadmill.

    PubMed

    McFadyen, Bradford J; Hegeman, Judith; Duysens, Jacques

    2009-10-01

    Bilaterally asymmetric stepping during walking is common to a number of pathological gaits (e.g., hemiplegia, limping). In the present work, the attention level of asymmetric stepping was studied by having subjects walk on a split-belt treadmill with symmetric (2 km/h) and asymmetric (2 km/h vs 4 km/h and 2 km/h vs 6 km/h) belt speeds both with and without a dual auditory Stroop task. There was no significant change in response reaction times across walking conditions or between walking and standing. The proportion of stance phase was unchanged by the dual task during symmetric walking. Stance phase proportions, however, significantly increased during dual tasking for the limb on the faster belt for both asymmetric conditions, while they decreased for the limb on the slower belt for the most asymmetric condition. There were also small modifications to double support proportions and a main effect of dual tasking to double support proportion variability. Observed dual task changes showed interference by the cognitive task with asymmetric gait performance, suggesting that asymmetric stepping, such as seen in limping gaits, requires more attention than symmetric walking. Such attention may, in part, be due to the dynamic balance required in asymmetric limb loading and unloading. PMID:19595592

  4. The effect of asymmetric vortex wake characteristics on a slender delta wing undergoing wing rock motion

    NASA Technical Reports Server (NTRS)

    Arena, A. S., Jr.; Nelson, R. C.

    1989-01-01

    An experimental investigation into the fluid mechanisms responsible for wing rock on a slender delta wing with 80 deg leading edge sweep has been conducted. Time history and flow visualization data are presented for a wide angle-of-attack range. The use of an air bearing spindle has allowed the motion of the wing to be free from bearing friction or mechanical hysteresis. A bistable static condition has been found in vortex breakdown at an angle of attack of 40 deg which causes an overshoot of the steady state rocking amplitude. Flow visualization experiments also reveal a difference in static and dynamic breakdown locations on the wing. A hysteresis loop in dynamic breakdown location similar to that seen on pitching delta wings was observed as the wing was undergoing the limit cycle oscillation.

  5. Exploring the Effect of Asymmetric Mitochondrial DNA Introgression on Estimating Niche Divergence in Morphologically Cryptic Species

    PubMed Central

    Wielstra, Ben; Arntzen, Jan W.

    2014-01-01

    If potential morphologically cryptic species, identified based on differentiated mitochondrial DNA, express ecological divergence, this increases support for their treatment as distinct species. However, mitochondrial DNA introgression hampers the correct estimation of ecological divergence. We test the hypothesis that estimated niche divergence differs when considering nuclear DNA composition or mitochondrial DNA type as representing the true species range. We use empirical data of two crested newt species (Amphibia: Triturus) which possess introgressed mitochondrial DNA from a third species in part of their ranges. We analyze the data in environmental space by determining Fisher distances in a principal component analysis and in geographical space by determining geographical overlap of species distribution models. We find that under mtDNA guidance in one of the two study cases niche divergence is overestimated, whereas in the other it is underestimated. In the light of our results we discuss the role of estimated niche divergence in species delineation. PMID:24743746

  6. Electrolyte and composition effects on the performances of asymmetric supercapacitors constructed with Mn3O4 nanoparticles-graphene nanocomposites

    NASA Astrophysics Data System (ADS)

    Xiao, Yuanhua; Cao, Yongbo; Gong, Yuyin; Zhang, Aiqin; Zhao, Jihong; Fang, Shaoming; Jia, Dianzeng; Li, Feng

    2014-01-01

    Nanocomposites of Mn3O4 nanoparticles and graphene (GR) nanosheets - Mn3O4@GR can be made by growing Mn3O4 nanoparticles directly on the surfaces of GR in solvothermal reactions. The asymmetric supercapacitors constructed with Mn3O4@GR as positive and activated carbon (AC) as negative electrodes, respectively, show highly enhanced performances in energy storage. It was found that the electrolytes employed in constructing electrodes of the devices can influence the performances of Mn3O4@GR supercapacitors dramatically. Compared to their energy density in KOH electrolyte, the devices exhibit improved charge storage performances in Na2SO4 electrolyte. Furthermore, the charge storage abilities of the devices are closely related to the amount of Mn3O4 nanoparticles loaded onto the surface of GR nanosheets. The performances of Mn3O4@GR//AC asymmetric supercapacitors can be optimized by carefully tailoring the composition of electrode materials and adjusting the electrolytes for making the devices.

  7. EFFECTS OF ASYMMETRIC FLOWS IN SOLAR CONVECTION ON OSCILLATION MODES

    SciTech Connect

    Baldner, Charles S.; Schou, Jesper

    2012-11-20

    Many helioseismic measurements suffer from substantial systematic errors. A particularly frustrating one is that time-distance measurements suffer from a large center to limb effect which looks very similar to the finite light travel time, except that the magnitude depends on the observable used and can have the opposite sign. This has frustrated attempts to determine the deep meridional flow in the solar convection zone, with Zhao et al. applying an ad hoc correction with little physical basis to correct the data. In this Letter, we propose that part of this effect can be explained by the highly asymmetrical nature of the solar granulation which results in what appears to the oscillation modes as a net radial flow, thereby imparting a phase shift on the modes as a function of observing height and thus heliocentric angle.

  8. Photovoltaic effect in individual asymmetrically contacted lead sulfide nanosheets.

    PubMed

    Dogan, Sedat; Bielewicz, Thomas; Lebedeva, Vera; Klinke, Christian

    2015-03-21

    Solution-processable, two-dimensional semiconductors are promising optoelectronic materials which could find application in low-cost solar cells. Lead sulfide nanocrystals raised attention since the effective band gap can be adapted over a wide range by electronic confinement and observed multi-exciton generation promises higher efficiencies. We report on the influence of the contact metal work function on the properties of transistors based on individual two-dimensional lead sulfide nanosheets. Using palladium we observed mobilities of up to 31 cm(2) V(-1) s(-1). Furthermore, we demonstrate that asymmetrically contacted nanosheets show photovoltaic effect and that the nanosheets' height has a decisive impact on the device performance. Nanosheets with a thickness of 5.4 nm contacted with platinum and titanium show a power conversion efficiency of up to 0.94% (EQE 75.70%). The results underline the high hopes put on such materials. PMID:25673356

  9. Photovoltaic effect in individual asymmetrically contacted lead sulfide nanosheets

    NASA Astrophysics Data System (ADS)

    Dogan, Sedat; Bielewicz, Thomas; Lebedeva, Vera; Klinke, Christian

    2015-03-01

    Solution-processable, two-dimensional semiconductors are promising optoelectronic materials which could find application in low-cost solar cells. Lead sulfide nanocrystals raised attention since the effective band gap can be adapted over a wide range by electronic confinement and observed multi-exciton generation promises higher efficiencies. We report on the influence of the contact metal work function on the properties of transistors based on individual two-dimensional lead sulfide nanosheets. Using palladium we observed mobilities of up to 31 cm2 V-1 s-1. Furthermore, we demonstrate that asymmetrically contacted nanosheets show photovoltaic effect and that the nanosheets' height has a decisive impact on the device performance. Nanosheets with a thickness of 5.4 nm contacted with platinum and titanium show a power conversion efficiency of up to 0.94% (EQE 75.70%). The results underline the high hopes put on such materials.Solution-processable, two-dimensional semiconductors are promising optoelectronic materials which could find application in low-cost solar cells. Lead sulfide nanocrystals raised attention since the effective band gap can be adapted over a wide range by electronic confinement and observed multi-exciton generation promises higher efficiencies. We report on the influence of the contact metal work function on the properties of transistors based on individual two-dimensional lead sulfide nanosheets. Using palladium we observed mobilities of up to 31 cm2 V-1 s-1. Furthermore, we demonstrate that asymmetrically contacted nanosheets show photovoltaic effect and that the nanosheets' height has a decisive impact on the device performance. Nanosheets with a thickness of 5.4 nm contacted with platinum and titanium show a power conversion efficiency of up to 0.94% (EQE 75.70%). The results underline the high hopes put on such materials. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr06957a

  10. Cell-sized asymmetric lipid vesicles facilitate the investigation of asymmetric membranes.

    PubMed

    Kamiya, Koki; Kawano, Ryuji; Osaki, Toshihisa; Akiyoshi, Kazunari; Takeuchi, Shoji

    2016-09-01

    Asymmetric lipid giant vesicles have been used to model the biochemical reactions in cell membranes. However, methods for producing asymmetric giant vesicles lead to the inclusion of an organic solvent layer that affects the mechanical and physical characteristics of the membrane. Here we describe the formation of asymmetric giant vesicles that include little organic solvent, and use them to investigate the dynamic responses of lipid molecules in the vesicle membrane. We formed the giant vesicles via the inhomogeneous break-up of a lipid microtube generated by applying a jet flow to an asymmetric planar lipid bilayer. The asymmetric giant vesicles showed a lipid flip-flop behaviour in the membrane, superficially similar to the lipid flip-flop activity observed in apoptotic cells. In vitro synthesis of membrane proteins into the asymmetric giant vesicles revealed that the lipid asymmetry in bilayer membranes improves the reconstitution ratio of membrane proteins. Our asymmetric giant vesicles will be useful in elucidating lipid-lipid and lipid-membrane protein interactions involved in the regulation of cellular functions. PMID:27554415

  11. Effect of asymmetrical eddy currents on magnetic diagnosis signals for equilibrium reconstruction in the Sino-UNIted Spherical Tokamak.

    PubMed

    Jiang, Y Z; Tan, Y; Gao, Z; Wang, L

    2014-11-01

    The vacuum vessel of Sino-UNIted Spherical Tokamak was split into two insulated hemispheres, both of which were insulated from the central cylinder. The eddy currents flowing in the vacuum vessel would become asymmetrical due to discontinuity. A 3D finite elements model was applied in order to study the eddy currents. The modeling results indicated that when the Poloidal Field (PF) was applied, the induced eddy currents would flow in the toroidal direction in the center of the hemispheres and would be forced to turn to the poloidal and radial directions due to the insulated slit. Since the eddy currents converged on the top and bottom of the vessel, the current densities there tended to be much higher than those in the equatorial plane were. Moreover, the eddy currents on the top and bottom of vacuum vessel had the same direction when the current flowed in the PF coils. These features resulted in the leading phases of signals on the top and bottom flux loops when compared with the PF waveforms. PMID:25430380

  12. Effect of asymmetrical eddy currents on magnetic diagnosis signals for equilibrium reconstruction in the Sino-UNIted Spherical Tokamaka)

    NASA Astrophysics Data System (ADS)

    Jiang, Y. Z.; Tan, Y.; Gao, Z.; Wang, L.

    2014-11-01

    The vacuum vessel of Sino-UNIted Spherical Tokamak was split into two insulated hemispheres, both of which were insulated from the central cylinder. The eddy currents flowing in the vacuum vessel would become asymmetrical due to discontinuity. A 3D finite elements model was applied in order to study the eddy currents. The modeling results indicated that when the Poloidal Field (PF) was applied, the induced eddy currents would flow in the toroidal direction in the center of the hemispheres and would be forced to turn to the poloidal and radial directions due to the insulated slit. Since the eddy currents converged on the top and bottom of the vessel, the current densities there tended to be much higher than those in the equatorial plane were. Moreover, the eddy currents on the top and bottom of vacuum vessel had the same direction when the current flowed in the PF coils. These features resulted in the leading phases of signals on the top and bottom flux loops when compared with the PF waveforms.

  13. Triazolium based ionic liquid crystals: Effect of asymmetric substitution

    SciTech Connect

    Stappert, K.; Mudring, A. -V.

    2015-01-27

    A new series of ten different asymmetrical 1-dodecyl-3-alkyl-triazolium bromides, [C12CnTr][Br], has been synthesized and their mesomorphic behavior studied by DSC (differential scanning calorimetry), POM (polarizing optical microscopy) and SAXS (small angle X-ray scattering). The influence of the chain length of the triazolium salts is investigated to explore the effect of asymmetric substitution on the phase behaviour of these compounds. For that reason, the length of one alkyl chain was varied from 14 to 1 carbon atoms (n = 14, 12, 10, 8–4, 2, 1) while the other alkyl chain was kept at 12 carbon. Single crystal X-ray structure analysis of compounds [C12C12Tr][Br] and [C12C5Tr][Br] reveal that the cations adopt a U-shaped conformation with head-to-head arranged triazolium cores. In contrast, for [C12C1Tr][Br], a rod like shape of the cation with interdigitated alkyl chains is found. All investigated compounds are thermotropic liquid crystals. Higher ordered smectic phases, smectic C as well as smectic A phases were found depending on the chain length of the cation. Moreover, the clearing point temperature decreases with decreasing chain length with exception for the n-dodecyl-3-alkyltrizoliumbromides with the two shortest alkyl chains, [C12C2Tr][Br] and [C12C1Tr][Br], which present higher clearing temperatures (86 and 156 °C) and are structurally distinctly different.

  14. Triazolium based ionic liquid crystals: Effect of asymmetric substitution

    DOE PAGESBeta

    Stappert, K.; Mudring, A. -V.

    2015-01-27

    A new series of ten different asymmetrical 1-dodecyl-3-alkyl-triazolium bromides, [C12CnTr][Br], has been synthesized and their mesomorphic behavior studied by DSC (differential scanning calorimetry), POM (polarizing optical microscopy) and SAXS (small angle X-ray scattering). The influence of the chain length of the triazolium salts is investigated to explore the effect of asymmetric substitution on the phase behaviour of these compounds. For that reason, the length of one alkyl chain was varied from 14 to 1 carbon atoms (n = 14, 12, 10, 8–4, 2, 1) while the other alkyl chain was kept at 12 carbon. Single crystal X-ray structure analysis ofmore » compounds [C12C12Tr][Br] and [C12C5Tr][Br] reveal that the cations adopt a U-shaped conformation with head-to-head arranged triazolium cores. In contrast, for [C12C1Tr][Br], a rod like shape of the cation with interdigitated alkyl chains is found. All investigated compounds are thermotropic liquid crystals. Higher ordered smectic phases, smectic C as well as smectic A phases were found depending on the chain length of the cation. Moreover, the clearing point temperature decreases with decreasing chain length with exception for the n-dodecyl-3-alkyltrizoliumbromides with the two shortest alkyl chains, [C12C2Tr][Br] and [C12C1Tr][Br], which present higher clearing temperatures (86 and 156 °C) and are structurally distinctly different.« less

  15. The effects of asymmetric hearing on bilateral brainstem function: findings in children with bimodal (electric and acoustic) hearing.

    PubMed

    Polonenko, Melissa J; Papsin, Blake C; Gordon, Karen A

    2015-01-01

    As implantation criteria are broadening to include children with asymmetric hearing loss, it is important to determine the degree of residual hearing needed to protect the bilateral auditory pathways for binaural hearing and whether there is a sensitive period in development for implantation in these children. We have been studying these questions in a growing cohort of children. In the present study, auditory brainstem responses were recorded in 21 children who had 2.2 ± 2.2 years of bimodal hearing. Responses were evoked by 11-Hz acoustic clicks presented to the non-implanted ear and with biphasic electric pulses presented to the implanted ear. Twelve of these children also completed a behavioural task in which they were asked to which side of their heads bilaterally presented clicks/pulses that varied in interaural level or timing lateralized. All children experienced a delay in the non-implanted ear that resulted in 2.0 ± 0.35 ms longer peak latencies. These were further prolonged in 7 children as measured by longer interwave latencies from this ear than from the implanted ear. Despite large asymmetries in timing of brainstem activity between the two ears, all children perceived changes in interaural level differences. They were unable to detect differences in interaural timing cues. Symmetric brainstem function suggests bilateral development was preserved in some children. Future work will explore whether these children have better potential for developing binaural hearing using bimodal input. PMID:25998954

  16. Dynamic JUNQ inclusion bodies are asymmetrically inherited in mammalian cell lines through the asymmetric partitioning of vimentin

    PubMed Central

    Ogrodnik, Mikołaj; Salmonowicz, Hanna; Brown, Rachel; Turkowska, Joanna; Średniawa, Władysław; Pattabiraman, Sundararaghavan; Amen, Triana; Abraham, Ayelet-chen; Eichler, Noam; Lyakhovetsky, Roman; Kaganovich, Daniel

    2014-01-01

    Aging is associated with the accumulation of several types of damage: in particular, damage to the proteome. Recent work points to a conserved replicative rejuvenation mechanism that works by preventing the inheritance of damaged and misfolded proteins by specific cells during division. Asymmetric inheritance of misfolded and aggregated proteins has been shown in bacteria and yeast, but relatively little evidence exists for a similar mechanism in mammalian cells. Here, we demonstrate, using long-term 4D imaging, that the vimentin intermediate filament establishes mitotic polarity in mammalian cell lines and mediates the asymmetric partitioning of damaged proteins. We show that mammalian JUNQ inclusion bodies containing soluble misfolded proteins are inherited asymmetrically, similarly to JUNQ quality-control inclusions observed in yeast. Mammalian IPOD-like inclusion bodies, meanwhile, are not always inherited by the same cell as the JUNQ. Our study suggests that the mammalian cytoskeleton and intermediate filaments provide the physical scaffold for asymmetric inheritance of dynamic quality-control JUNQ inclusions. Mammalian IPOD inclusions containing amyloidogenic proteins are not partitioned as effectively during mitosis as their counterparts in yeast. These findings provide a valuable mechanistic basis for studying the process of asymmetric inheritance in mammalian cells, including cells potentially undergoing polar divisions, such as differentiating stem cells and cancer cells. PMID:24843142

  17. Comparison of the effects of symmetric and asymmetric temperature elevation and CO2 enrichment on yield and evapotranspiration of winter wheat (Triticum aestivum L.)

    PubMed Central

    Qiao, Yunzhou; Liu, Huiling; Kellomäki, Seppo; Peltola, Heli; Liu, Yueyan; Dong, Baodi; Shi, Changhai; Zhang, Huizhen; Zhang, Chao; Gong, Jinnan; Si, Fuyan; Li, Dongxiao; Zheng, Xin; Liu, Mengyu

    2014-01-01

    Under the changing climate, asymmetric warming pattern would be more likely during day and night time, instead of symmetric one. Concurrently, the growth responses and water use of plants may be different compared with those estimated based on symmetric warming. In this work, it was compared with the effects of symmetric (ETs) and asymmetric (ETa) elevation of temperature alone, and in interaction with elevated carbon dioxide concentration (EC), on the grain yield (GY) and evapotranspiration in winter wheat (Triticum aestivum L.) based on pot experiment in the North China Plain (NCP). The experiment was carried out in six enclosed-top chambers with following climate treatments: (1) ambient temperature and ambient CO2 (CON), (2) ambient temperature and elevated CO2 (EC), (3) elevated temperature and ambient CO2 (ETs; ETa), and (4) elevated temperature and elevated CO2 (ECETs, ECETa). In symmetric warming, temperature was increased by 3°C and in asymmetric one by 3.5°C during night and 2.5°C during daytime, respectively. As a result, GY was in ETa and ETs 15.6 (P < 0.05) and 10.3% (P < 0.05) lower than that in CON. In ECETs and ECETa treatments, GY was 14.9 (P < 0.05) and 9.1% (P < 0.05) higher than that in CON. Opposite to GY, evapotranspiration was 7.8 (P < 0.05) and 17.9% (P < 0.05) higher in ETa and ETs treatments and 7.2 (P < 0.05) and 2.1% (P > 0.05) lower in ECETs and ECETa treatments compared with CON. Thus, GY of wheat could be expected to increase under the changing climate with concurrent elevation of CO2 and temperature as a result of increased WUE under the elevated CO2. However, the gain would be lower under ETa than that estimated based on ETs due to higher evapotranspiration. PMID:24963392

  18. Nonequilibrium ionization effects in asymmetrically heated loops. [in solar corona

    NASA Technical Reports Server (NTRS)

    Spadaro, D.; Antiochos, Spiro K.; Mariska, J. T.

    1991-01-01

    The effects of nonequilibrium ionization on magnetic loop models with a steady siphon flow that is driven by a nonuniform heating rate are investigated. The model developed by Mariska (1988) to explain the observed redshifts of transition region emission lines is examined, and the number densities of the ions of carbon and oxygen along the loop are computed, with and without the approximation of ionization equilibrium. Considerable deviations from equilibrium were found. In order to determine the consequences of these nonequilibrium effects on the characteristics of the EUV emission from the loop plasma, the profiles and wavelength positions of all the important emission lines due to carbon and oxygen were calculated. The calculations are in broad agreement with Mariska's conclusions, although they show a significant diminution of the Doppler shifts, as well as modifications to the line widths. It is concluded that the inclusion of nonequilibrium effects make it more difficult to reproduce the observed characteristics of the solar transition region by means of the asymmetric-heating models.

  19. Why are children living in poverty getting fatter?

    PubMed

    Pagani, Linda S; Huot, Céline

    2007-10-01

    In recent decades, there has been a dramatic increase in unhealthy weight for both children and adults. The Canadian standard of living has changed in favour of more easily prepared, calorie-dense foods and sedentary practices. Many family characteristics have also changed over the past 50 years. More Canadian families are living in disadvantaged situations, forecasting a host of unhealthy behaviours and attitudes in adults. The poor are not only getting poorer, they are also becoming heavier. Children from disadvantaged families seem to be leading the trend in increasing prevalence of unhealthy weight. Because they live in neighbourhoods that are perceived as unsafe, these children are likely spending more time indoors. This is associated with watching more television, which not only displaces other forms of educational and active entertainment but also places them at risk of learning inaccurate information about proper eating. Social science research helps identify factors contributing most to the rise in excess weight within this population, thus providing essential clues for effective approaches to its eradication. PMID:19030449

  20. Effects of applied electric and magnetic fields on the nonlinear optical properties of asymmetric GaAs /Ga1-xAlx As double inverse parabolic quantum well

    NASA Astrophysics Data System (ADS)

    Al, E. B.; Ungan, F.; Yesilgul, U.; Kasapoglu, E.; Sari, H.; Sökmen, I.

    2015-09-01

    The combined effects of electric and magnetic fields on the optical absorption coefficients and refractive index changes related to the intersubband transitions within the conduction band of asymmetric GaAs /Ga1-xAlxAs double inverse parabolic quantum wells are studied using the effective-mass approximation and the compact density-matrix approach. The results are presented as a function of the incident photon energy for the different values of the electromagnetic fields and the structure parameters such as quantum well width and the Al concentration at the well center. It is found that the optical absorption coefficients and the refractive index changes are strongly affected not only by the magnitudes of the electric and magnetic fields but also by the structure parameters of the system.

  1. Exchange bias effect modified asymmetric magnetization reversal in Ni/YMnO3 multiferroic bilayers

    NASA Astrophysics Data System (ADS)

    Gong, Junlu; Zheng, Dongxing; Li, Dong; Jin, Chao; Li, Peng; Feng, Liefeng; Bai, Haili

    2016-04-01

    Exchange bias (EB) effect modified asymmetric magnetization reversal in Ni/YMnO3 multiferroic bilayers was investigated by combining anisotropic magnetoresistance (AMR) with free energy methods. The promotion and inhibition effects of EB field on magnetization rotation result in the asymmetry of magnetization reversal. The AMR curves exhibit shape transition from arc-like to sin2θH-dependence with increasing external fields due to the competition between Zeeman energy and interfacial coupling energy. The phase shift and asymmetric behaviors become weak as the EB field decreases. Our work suggests that controlling the EB effect can be an alternative way to manipulate the magnetization reversal in exchange biased systems.

  2. Effects of asymmetric nuclear introgression, introgressive mitochondrial sweep, and purifying selection on phylogenetic reconstruction and divergence estimates in the Pacific clade of Locustella warblers.

    PubMed

    Drovetski, Sergei V; Semenov, Georgy; Red'kin, Yaroslav A; Sotnikov, Vladimir N; Fadeev, Igor V; Koblik, Evgeniy A

    2015-01-01

    When isolated but reproductively compatible populations expand geographically and meet, simulations predict asymmetric introgression of neutral loci from a local to invading taxon. Genetic introgression may affect phylogenetic reconstruction by obscuring topology and divergence estimates. We combined phylogenetic analysis of sequences from one mtDNA and 12 nuDNA loci with analysis of gene flow among 5 species of Pacific Locustella warblers to test for presence of genetic introgression and its effects on tree topology and divergence estimates. Our data showed that nuDNA introgression was substantial and asymmetrical among all members of superspecies groups whereas mtDNA showed no introgression except a single species pair where the invader's mtDNA was swept by mtDNA of the local species. This introgressive sweep of mtDNA had the opposite direction of the nuDNA introgression and resulted in the paraphyly of the local species' mtDNA haplotypes with respect to those of the invader. Тhe multilocus nuDNA species tree resolved all inter- and intraspecific relationships despite substantial introgression. However, the node ages on the species tree may be underestimated as suggested by the differences in node age estimates based on non-introgressing mtDNA and introgressing nuDNA. In turn, the introgressive sweep and strong purifying selection appear to elongate internal branches in the mtDNA gene tree. PMID:25849039

  3. Many-body Effects and the Role of Indirect Excitons in Asymmetric InGaAs/GaAs Double Quantum Wells

    NASA Astrophysics Data System (ADS)

    Smallwood, Christopher; Suzuki, Takeshi; Singh, Rohan; Autry, Travis; Day, Matthew; Jabeen, Fauzia; Cundiff, Steven

    In semiconductor research, a fundamental question is how excitons in nearby but distinct spatial locations interact and exchange energy. In quantum well heterostructures, these interactions can be conveniently probed via optical coherent multidimensional spectroscopy (CMDS). Recently, it has been shown using CMDS that reducing the GaAs barrier from 30 nm to 10 nm between two asymmetric InGaAs quantum wells results in interactions driven by many-body effects. Here, we use the technique to show that for narrower barrier thicknesses, the interactions are accompanied by an emergence of spatially indirect excitons. Quantitative measurements of the effects are presented, which will be useful in tailoring GaAs heterostructure devices, and may also inform the role that excitonic interactions play in more complicated systems like microcavity polariton structures and/or photosynthetic light harvesting complexes.

  4. New ligands for the asymmetric dihydroxylation

    SciTech Connect

    Becker, H.; King, S.B.; Richardson, P.

    1995-12-31

    The asymmetric dibydroxylation of olefins in the presence of cinchona alkaloid derivatives (the AD reaction) has proven to be a reliable method in organic syntheses. For most olefins, the enantioselectivities using the {open_quotes}standard{close_quotes} phathalazine ligands are excellent; however, facial selectivity is still moderate for some olefins. 2,3-Diphenyl pyrazinopyridazine (DPP) and anthraquinone (AQN) as spacers for the {open_quotes}pseudo enantiomeric{close_quotes} alkaloids dihydroquinidine (DHQD) or dihydroquinine (DHQ) give superior enantioselectivities for almost all olefins.

  5. Effect of the active region thickness on characteristics of semiconductor lasers based on asymmetric AlGaAs/GaAs/InGaAs heterostructures with broadened waveguide

    SciTech Connect

    Vinokurov, D. A. Vasilyeva, V. V.; Kapitonov, V. A.; Lyutetskiy, A. V.; Nikolaev, D. N.; Pikhtin, N. A.; Slipchenko, S. O.; Stankevich, A. L.; Shamakhov, V. V.; Fetisova, N. V.; Tarasov, I. S.

    2010-02-15

    The effect of the active region thickness on the basic characteristics of high-power semiconductor lasers based on AlGaAs/GaAs/InGaAs asymmetric separate-confinement heterostructures grown by MOCVD epitaxy has been studied. It is shown that the threshold current, temperature sensitivity of the threshold current density, internal quantum efficiency of stimulated emission, and differential quantum efficiency are improved as the active region thickness increases. It is demonstrated that the maximum attainable optical emission power of a semiconductor laser and the internal quantum efficiency of photoluminescence are the most sensitive to defect formation in the heterostructure and become lower as the critical thickness of the strained In{sub x}Ga{sub 1-x} As layer in the active region is exceeded.

  6. Turning symmetric an asymmetric hydrogen bond with the inclusion of nuclear quantum effects: the case of the [CN···H···NC]- complex.

    PubMed

    Moreno, Diego V; González, Sergio A; Reyes, Andrés

    2011-01-14

    Nuclear quantum effects (NQE) on the geometry, energy, and electronic structure of the [CN·L·NC](-) complex (L = H, D, T) are investigated with the recently developed APMO/MP2 code. This code implements the nuclear molecular orbital approach (NMO) at the Hartree-Fock (HF) and MP2 levels of theory for electrons and quantum nuclei. In a first study, we examined the H/D/T isotope effects on the geometry and electronic structure of the CNH molecule at NMO/HF and NMO/MP2 levels of theory. We found that when increasing the hydrogen nuclear mass there is a reduction of the R(N-H) bond distance and an increase of the electronic population on the hydrogen atom. Our calculated bond distances are in good agreement with experimental and other theoretical results. In a second investigation, we explored the hydrogen NQE on the geometry of [CNHNC](-) complex at the NMO/HF and NMO/MP2 levels of theory. We discovered that while a NMO/HF calculation presented an asymmetric hydrogen bond, the NMO/MP2 calculation revealed a symmetric H-bond. We also examined the H/D/T isotope effects on the geometry and stabilization energy of the [CNHNC](-) complex. We noted that gradual increases in hydrogen mass led to reductions of the R(NN) distance and destabilization of the hydrogen bond (H-bond). A discussion of these results is given in terms of the hydrogen nuclear delocalization effects on the electronic structure and energy components. To the best of our knowledge, this is the first ab initio NMO study that reveals the importance of including nuclear quantum effects in conventional electronic structure calculations for an enhanced description of strong-low-barrier H-bonded systems. PMID:21241088

  7. Reflection-Asymmetric Nuclear Deformations within the Density Functional Theory

    SciTech Connect

    Olsen, E; Erler, J; Nazarewicz, W.; Stoitsov, M

    2012-01-01

    Within the nuclear density functional theory (DFT) we study the effect of reflection- asymmetric shapes on ground-state binding energies and binding energy differences. To this end, we developed the new DFT solver axialhfb that uses an approximate second-order gradient to solve the Hartree-Fock-Bogoliubov equations of superconducting DFT with the quasi-local Skyrme energy density functionals. Illustrative calculations are carried out for even- even isotopes of radium and thorium.

  8. Asymmetric Reconnection in the Terrestrial Reconnection EXperiment

    NASA Astrophysics Data System (ADS)

    Olson, Joseph; Egedal, Jan; Forest, Cary; Wallace, John; TREX Team; MPDX Team

    2014-10-01

    The Terrestrial Reconnection EXperiment (TREX) is a new and versatile addition to the Wisconsin Plasma Astrophysics Laboratory (WiPAL) at the University of Wisconsin-Madison. TREX is optimized for the study of kinetic reconnection in various regimes and to provide the first laboratory evidence in support of a new model describing the dynamics of trapped electrons and correlating pressure anisotropy. The initial configuration implemented in TREX is specially designed to study asymmetric reconnection scenarios. These are particularly relevant to the dayside magnetopause in which the plasma beta of the solar wind and of the magnetosphere can differ by factors of 100-1000. The configuration utilizes the Helmholtz coils to produce a static, uniform magnetic field up to 275 G through the 3 m spherical vacuum vessel. Plasma is produced on a 10 s rep rate while two internal coils are pulsed, creating an opposing magnetic field to induce reconnection with asymmetric high and low beta inflows. A Langmuir and Bdot probe array is swept in between pulses to build up the magnetic profiles in the reconnection region. Preliminary data from these initial runs will be presented.

  9. Ab initio study on the size effect of symmetric and asymmetric ferroelectric tunnel junctions: A comprehensive picture with regard to the details of electrode/ferroelectric interfaces

    NASA Astrophysics Data System (ADS)

    Chen, W. J.; Zheng, Yue; Luo, X.; Wang, B.; Woo, C. H.

    2013-08-01

    Ferroelectric size effect of BaTiO3 (BTO) tunnel junctions with metal Pt and/or oxide SrRuO3 (SRO) electrodes has been comprehensively investigated by the first-principle calculations. A vacuum layer is included in the supercell calculations, so that full-relaxation is achieved without artificial constraint on the supercell strains. We have constructed all of ten possible types of tunnel junctions with either symmetric or asymmetric geometries to systematically explore the influence of electrode/ferroelectric interfaces. The characteristics of atomic structure, polarization, charge density, and electrostatic potential for different geometries and sizes are revealed. It is found that the ferroelectric stability of a tunnel junction depends significantly on the details of the two electrode/ferroelectric interfaces, which present specific short- and long-range properties, e.g., local bonding environment, electronic screening, built-in field, etc. Result shows that Pt/BTO interfaces have strong coupling with ferroelectric distortion and thus play more dominant roles than the SRO/BTO interfaces in affecting the ferroelectric stability of the tunnel junctions. Particularly, it is found that Pt2/TiO2 interface can induce collective ferroelectric distortion in the initially non-distorted barrier. With a full-relaxation of the strains, an abnormal enhancement of ferroelectricity by Pt2/BaO interface due to Pt-O bonding effect is demonstrated, where a strong interfacial-bonding-related polarizing field is verified. Also importantly, polarization stability of asymmetric tunnel junctions is found dependent on direction, manifested with the appearing of a new critical thickness, below which the tunnel junction loses polarization bistability. Furthermore, it shows that the local features of a specific electrode/ferroelectric interface (e.g., the interfacial atomic structure, local polarization, charge transfer, and potential step) are well kept in different types of tunnel

  10. Evolutionary Stability in the Asymmetric Volunteer's Dilemma

    PubMed Central

    Li, Yao-Tang

    2014-01-01

    It is often assumed that in public goods games, contributors are either strong or weak players and each individual has an equal probability of exhibiting cooperation. It is difficult to explain why the public good is produced by strong individuals in some cooperation systems, and by weak individuals in others. Viewing the asymmetric volunteer's dilemma game as an evolutionary game, we find that whether the strong or the weak players produce the public good depends on the initial condition (i.e., phenotype or initial strategy of individuals). These different evolutionarily stable strategies (ESS) associated with different initial conditions, can be interpreted as the production modes of public goods of different cooperation systems. A further analysis revealed that the strong player adopts a pure strategy but mixed strategies for the weak players to produce the public good, and that the probability of volunteering by weak players decreases with increasing group size or decreasing cost-benefit ratio. Our model shows that the defection probability of a “strong” player is greater than the “weak” players in the model of Diekmann (1993). This contradicts Selten's (1980) model that public goods can only be produced by a strong player, is not an evolutionarily stable strategy, and will therefore disappear over evolutionary time. Our public good model with ESS has thus extended previous interpretations that the public good can only be produced by strong players in an asymmetric game. PMID:25111781

  11. Asymmetrical Inheritance of Plasmids Depends on Dynamic Cellular Geometry and Volume Exclusion Effects

    PubMed Central

    Marquez-Lago, Tatiana T.

    2015-01-01

    The asymmetrical inheritance of plasmid DNA, as well as other cellular components, has been shown to be involved in replicative aging. In Saccharomyces cerevisiae, there is an ongoing debate regarding the mechanisms underlying this important asymmetry. Currently proposed models suggest it is established via diffusion, but differ on whether a diffusion barrier is necessary or not. However, no study so far incorporated key aspects to segregation, such as dynamic morphology changes throughout anaphase or plasmids size. Here, we determine the distinct effects and contributions of individual cellular variability, plasmid volume and moving boundaries in the asymmetric segregation of plasmids. We do this by measuring cellular nuclear geometries and plasmid diffusion rates with confocal microscopy, subsequently incorporating this data into a growing domain stochastic spatial simulator. Our modelling and simulations confirms that plasmid asymmetrical inheritance does not require an active barrier to diffusion, and provides a full analysis on plasmid size effects. PMID:26468952

  12. Asymmetrical Inheritance of Plasmids Depends on Dynamic Cellular Geometry and Volume Exclusion Effects.

    PubMed

    Denton, Jai A; Ghosh, Atiyo; Marquez-Lago, Tatiana T

    2015-01-01

    The asymmetrical inheritance of plasmid DNA, as well as other cellular components, has been shown to be involved in replicative aging. In Saccharomyces cerevisiae, there is an ongoing debate regarding the mechanisms underlying this important asymmetry. Currently proposed models suggest it is established via diffusion, but differ on whether a diffusion barrier is necessary or not. However, no study so far incorporated key aspects to segregation, such as dynamic morphology changes throughout anaphase or plasmids size. Here, we determine the distinct effects and contributions of individual cellular variability, plasmid volume and moving boundaries in the asymmetric segregation of plasmids. We do this by measuring cellular nuclear geometries and plasmid diffusion rates with confocal microscopy, subsequently incorporating this data into a growing domain stochastic spatial simulator. Our modelling and simulations confirms that plasmid asymmetrical inheritance does not require an active barrier to diffusion, and provides a full analysis on plasmid size effects. PMID:26468952

  13. Probing the "additive effect" in the proline and proline hydroxamic acid catalyzed asymmetric addition of nitroalkanes to cyclic enones.

    PubMed

    Hanessian, Stephen; Govindan, Subramaniyan; Warrier, Jayakumar S

    2005-11-01

    The effect of chirality and steric bulk of 2,5-disubstituted piperazines as additives in the conjugate addition of 2-nitropropane to cyclohexenone, catalyzed by l-proline, was investigated. Neither chirality nor steric bulk affects the enantioselectivity of addition, which gives 86-93% ee in the presence of achiral and chiral nonracemic 2,5-disubstituted piperazines. Proline hydroxamic acid is shown for the first time to be an effective organocatalyst in the same Michael reaction. PMID:16189834

  14. Limit laws for the asymmetric inclusion process.

    PubMed

    Reuveni, Shlomi; Eliazar, Iddo; Yechiali, Uri

    2012-12-01

    The Asymmetric Inclusion Process (ASIP) is a unidirectional lattice-gas flow model which was recently introduced as an exactly solvable 'Bosonic' counterpart of the 'Fermionic' asymmetric exclusion process. An iterative algorithm that allows the computation of the probability generating function (PGF) of the ASIP's steady state exists but practical considerations limit its applicability to small ASIP lattices. Large lattices, on the other hand, have been studied primarily via Monte Carlo simulations and were shown to display a wide spectrum of intriguing statistical phenomena. In this paper we bypass the need for direct computation of the PGF and explore the ASIP's asymptotic statistical behavior. We consider three different limiting regimes: heavy-traffic regime, large-system regime, and balanced-system regime. In each of these regimes we obtain-analytically and in closed form-stochastic limit laws for five key ASIP observables: traversal time, overall load, busy period, first occupied site, and draining time. The results obtained yield a detailed limit-laws perspective of the ASIP, numerical simulations demonstrate the applicability of these laws as useful approximations. PMID:23367919

  15. Asymmetric catalysis on the nanoscale: the organocatalytic approach to helicenes.

    PubMed

    Kötzner, Lisa; Webber, Matthew J; Martínez, Alberto; De Fusco, Claudia; List, Benjamin

    2014-05-12

    The first asymmetric organocatalytic synthesis of helicenes is reported. A novel SPINOL-derived phosphoric acid, bearing extended π-substituents, catalyzes the asymmetric synthesis of helicenes through an enantioselective Fischer indole reaction. A variety of azahelicenes and diazahelicenes could be obtained with good to excellent yields and enantioselectivities. PMID:24737692

  16. Effect of Geometric Azimuthal Asymmetrics of PPM Stack on Electron Beam Characteristics

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.

    2000-01-01

    A three-dimensional (3D) beam optics model has been developed using the electromagnetic particle-in-cell (PIC) code MAFIA. The model includes an electron beam with initial transverse velocity distribution focused by a periodic permanent magnet (PPM) stack. All components of the model are simulated in three dimensions allowing several azimuthally asymmetric traveling wave tube (TWT) characteristics to be investigated for the first time. These include C-magnets, shunts and magnet misalignment and their effects on electron beam behavior. The development of the model is presented and 3D TWT electron beam characteristics are compared in the absence of and under the influence of the azimuthally asymmetric characteristics described.

  17. Asymmetric morphology of the propagating jet

    NASA Astrophysics Data System (ADS)

    Hardee, Philip E.; Norman, Michael L.

    1990-12-01

    Simulations of slab jets propagating in constant atmospheres are reported for a range of jet velocities and Mach numbers. At early times, the jet maintains approximate axisymmetry within a backflowing cocoon. When the jet has penetrated farther into the external medium, the symmetry is broken by sideways oscillation and the leading edge of the jet moves about within a growing lobe. The oscillation results from nonlinear resonant amplification of the initial perturbation by the Kelvin-Helmholtz instability. Finally, the jet flaps chaotically within the growing lobe. The flapping is driven by turbulent vortices in the lobe. The basic picture of Scheuer's (1982) 'dentist's drill' model of the physical processes underlying asymmetric morphologies in radio galaxies is confirmed. The fluid motions in the lobe are found to govern the location of the drill bit. The morphology is time-dependent on relatively short time scales.

  18. Activation of the prefrontal cortex by unilateral transcranial direct current stimulation leads to an asymmetrical effect on risk preference in frames of gain and loss.

    PubMed

    Ye, Hang; Huang, Daqiang; Wang, Siqi; Zheng, Haoli; Luo, Jun; Chen, Shu

    2016-10-01

    Previous brain imaging and brain stimulation studies have suggested that the dorsolateral prefrontal cortex may be critical in regulating risk-taking behavior, although its specific causal effect on people's risk preference remains controversial. This paper studied the independent modulation of the activity of the right and left dorsolateral prefrontal cortex using various configurations of transcranial direct current stimulation. We designed a risk-measurement table and adopted a within-subject design to compare the same participant's risk preference before and after unilateral stimulation when presented with different frames of gain and loss. The results confirmed a hemispheric asymmetry and indicated that the right dorsolateral prefrontal cortex has an asymmetric effect on risk preference regarding frames of gain and loss. Enhancing the activity of the right dorsolateral prefrontal cortex significantly decreased the participants' degree of risk aversion in the gain frame, whereas it increased the participants' degree of risk aversion in the loss frame. Our findings provide important information regarding the impact of transcranial direct current stimulation on the risk preference of healthy participants. The effects observed in our experiment compared with those of previous studies provide further evidence of the effects of hemispheric and frame-dependent asymmetry. These findings may be helpful in understanding the neural basis of risk preference in humans, especially when faced with decisions involving possible gain or loss relative to the status quo. PMID:27507423

  19. Aerodynamic cause of the asymmetric wing deformation of insect wings

    NASA Astrophysics Data System (ADS)

    Luo, Haoxiang; Tian, Fangbao; Song, Jialei; Lu, Xi-Yun

    2012-11-01

    Insect wings typically exhibit significant asymmetric deformation patterns, where the magnitude of deflection during upstroke is greater than during downstroke. Such a feature is beneficial for the aerodynamics since it reduces the projected wing area during upstroke and leads to less negative lift. Previously, this asymmetry has been mainly attributed to the directional bending stiffness in the wing structure, e.g., one-way hinge, or a pre-existing camber in the wing surface. In the present study, we demonstrate that the asymmetric pattern can also be caused by the asymmetric force due to the flow, while the wing structure and kinematics are symmetric. A two-dimensional translating/pitching wing in a free stream is used as the model, and the wing is represented by an elastic sheet with large displacement. The result shows that, interestingly, the wing experiences larger deformation during upstroke even though the aerodynamic force is greater during downstroke. The physical mechanism of the phenomenon can be explained by the modulating effect of the aerodynamic force on the timing of storage/release of the elastic energy in the wing. Supported by NSF (No. CBET-0954381).

  20. Asymmetric pneumatization of the petrous apex.

    PubMed

    Roland, P S; Meyerhoff, W L; Judge, L O; Mickey, B E

    1990-07-01

    Three patients with high-intensity MR signals from one petrous apex, but nonpathologic fine-cut computed tomography are reported. In two of the three patients, normal bone marrow within the petrous apex on one side is believed to have generated the high-intensity signal. In one of the three patients, the etiology of the MR image remains obscure, but may represent the earliest stages of petrous cholesterol granuloma or mucocele. We have reviewed 500 head CT scans performed for non-otologic reasons, in an attempt to establish the frequency of this finding. The literature on MR and CT imaging of the petrous apex and asymmetric pneumatization of the petrous apex is reviewed. PMID:2117735

  1. Asymmetric multifractal scaling behavior in the Chinese stock market: Based on asymmetric MF-DFA

    NASA Astrophysics Data System (ADS)

    Cao, Guangxi; Cao, Jie; Xu, Longbing

    2013-02-01

    We utilized asymmetric multifractal detrended fluctuation analysis in this study to examine the asymmetric multifractal scaling behavior of Chinese stock markets with uptrends or downtrends. Results show that the multifractality degree of Chinese stock markets with uptrends is stronger than that of Chinese stock markets with downtrends. Correlation asymmetries are more evident in large fluctuations than in small fluctuations. By discussing the source of asymmetric multifractality, we find that multifractality is related to long-range correlations when the market is going up, whereas it is related to fat-tailed distribution when the market is going down. The main source of asymmetric scaling behavior in the Shanghai stock market are long-range correlations, whereas that in the Shenzhen stock market is fat-tailed distribution. An analysis of the time-varying feature of scaling asymmetries shows that the evolution trends of these scaling asymmetries are similar in the two Chinese stock markets. Major financial and economical events may enhance scaling asymmetries.

  2. Origin of Asymmetric Solvation Effects for Ions in Water and Organic Solvents Investigated Using Molecular Dynamics Simulations: The Swain Acity-Basity Scale Revisited.

    PubMed

    Reif, Maria M; Hünenberger, Philippe H

    2016-08-25

    The asymmetric solvation of ions can be defined as the tendency of a solvent to preferentially solvate anions over cations or cations over anions, at identical ionic charge magnitudes and effective sizes. Taking water as a reference, these effects are quantified experimentally for many solvents by the relative acity (A) and basity (B) parameters of the Swain scale. The goal of the present study is to investigate the asymmetric solvation of ions using molecular dynamics simulations, and to connect the results to this empirical scale. To this purpose, the charging free energies of alkali and halide ions, and of their hypothetical oppositely charged counterparts, are calculated in a variety of solvents. In a first set of calculations, artificial solvent models are considered that present either a charge or a shape asymmetry at the molecular level. The solvation asymmetry, probed by the difference in charging free energy between the two oppositely charged ions, is found to encompass a term quadratic in the ion charge, related to the different solvation structures around the anion and cation, and a term linear in the ion charge, related to the solvation structure around the uncharged ion-sized cavity. For these simple solvent models, the two terms are systematically counteracting each other, and it is argued that only the quadratic term should be retained when comparing the results of simulations involving physical solvents to experimental data. In a second set of calculations, 16 physical solvents are considered. The theoretical estimates for the acity A are found to correlate very well with the Swain parameters, whereas the correlation for B is very poor. Based on this observation, the Swain scale is reformulated into a new scale involving an asymmetry parameter Σ, positive for acitic solvents and negative for basitic ones, and a polarity parameter Π. This revised scale has the same predictive power as the original scale, but it characterizes asymmetry in an

  3. Asymmetrical Capacitors for Propulsion and the ISR Asymmetrical Capacitator Thruster, Experimental Results and Improved Designs

    NASA Technical Reports Server (NTRS)

    Canning, Francis; Winet, Ed; Ice, Bob; Melcher, Cory; Pesavento, Phil; Holmes, Alan; Butler, Carey; Cole, John; Campbell, Jonathan

    2004-01-01

    The outline of this viewgraph presentation on asymmetrical capacitor thruster development includes: 1) Test apparatus; 2) Devices tested; 3) Circuits used; 4) Data collected (Time averaged, Time resolved); 5) Patterns observed; 6) Force calculation; 7) Electrostatic modeling; 8) Understand it all.

  4. Rawal's catalyst as an effective stimulant for the highly asymmetric Michael addition of β-keto esters to functionally rich nitro-olefins.

    PubMed

    Suresh Kumar, A; Prabhakar Reddy, T; Madhavachary, R; Ramachary, Dhevalapally B

    2016-06-15

    A general approach to asymmetric synthesis of highly substituted dihydroquinolines was achieved through neighboring ortho-amino group engaged sequential Michael/amination/dehydration reactions on (E)-2-(2-nitrovinyl)anilines with cyclic and acyclic β-keto esters in the presence of a catalytic amount of Rawal's quinidine-NH-benzyl squaramide followed by TFA. PMID:26611712

  5. Error induced by the estimation of the corneal power and the effective lens position with a rotationally asymmetric refractive multifocal intraocular lens

    PubMed Central

    Piñero, David P.; Camps, Vicente J.; Ramón, María L.; Mateo, Verónica; Pérez-Cambrodí, Rafael J.

    2015-01-01

    AIM To evaluate the prediction error in intraocular lens (IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position (ELP). METHODS Retrospective study including a total of 25 eyes of 13 patients (age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL (Oculentis GmbH, Germany). In all cases, an adjusted IOL power (PIOLadj) was calculated based on Gaussian optics using a variable keratometric index value (nkadj) for the estimation of the corneal power (Pkadj) and on a new value for ELP (ELPadj) obtained by multiple regression analysis. This PIOLadj was compared with the IOL power implanted (PIOLReal) and the value proposed by three conventional formulas (Haigis, Hoffer Q and Holladay I). RESULTS PIOLReal was not significantly different than PIOLadj and Holladay IOL power (P>0.05). In the Bland and Altman analysis, PIOLadj showed lower mean difference (-0.07 D) and limits of agreement (of 1.47 and -1.61 D) when compared to PIOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELPadj was significantly lower than ELP calculated with other conventional formulas (P<0.01) and was found to be dependent on axial length, anterior chamber depth and Pkadj. CONCLUSION Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing the keratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors. PMID:26085998

  6. Edge-Channel Photo-Effect In Asymmetric Two-Dimensional Systems

    SciTech Connect

    Vasilyev, Yu. B.; Meltser, B. Ya.; Ivanov, S. V.; Kop'ev, P. S.; Stellmach, C.; Gouider, F.; Nachtwei, G.

    2011-12-23

    We report on the photo-effect in an asymmetric two dimensional electron system where edge currents are induced by homogeneous terahertz (THz) radiation in tilted magnetic field without any external bias. We discuss the features of the observed effect and its mechanism taking into account properties of edge states in magnetic fields. The process is understood as the quantum Hall effect associated with electron-hole pairs generated in Landau levels by THz radiation under CR conditions.

  7. Probing the effect of dopants (donors) within InAs/InGaAs/InAlAs Asymmetric Heterostructure wafer by magneto-THz spectroscopy

    NASA Astrophysics Data System (ADS)

    Pakmehr, Mehdi; Heyn, Christian; Hansen, Wolfgang

    Probing the effect of impurities within semiconductor structures have been the topic of interest both from applied and scientific point of views. We studied the effect of dopants (donors) within InAs/InGaAs/InAlAs asymmetric heterostructure wafer by means of THz magneto-transmission (TR) spectroscopy, in conjunction with THz magneto-photoresponse (PR) spectroscopy. The sample wafer has been immersed in pumped liquid Helium at 1.6 K, while being exposed to sweeping magnetic field up to 10 Tesla, with THz laser beam (1.4 THz) being focused on sample by off-axis parabolic mirror. The transmitted beam was detected by silicon composite bolometer. Two broad absorption features other than sharp Cyclotron resonance (CR) absorption dip within magneto-TR signal attributed to 1s -->2P transition within donors of doped layer (InAlAs) in heterostructure. We plan to discuss the analysis of magneto-TR signal, in conjunction with Magneto-PR signals from Hall bar samples made from same type of wafer at same frequency to clarify how dopants could possibly alter these signals.

  8. Effects of medium-induced {rho}-{omega} meson mixing on the equation of state in isospin-asymmetric nuclear matter

    SciTech Connect

    Jiang Weizhou; Li Baoan

    2009-10-15

    We reexamine effects of the {rho}-{omega} meson mixing mediated by nucleon polarizations on the symmetry energy in isospin-asymmetric nuclear matter. Taking into account the rearrangement term neglected in previous studies by others, we evaluate the {rho}-{omega} mixing angle in a novel way within the relativistic mean-field models with and without chiral limits. It is found that the symmetry energy is significantly softened at high densities contrary to the finding in earlier studies. As the first step of going beyond the lowest-order calculations, we also solve the Dyson equation for the {rho}-{omega} mixing. In this case, it is found that the symmetry energy is not only significantly softened by the {rho}-{omega}mixing at suprasaturation densities, similar to the lowest-order {rho}-{omega} mixing, but interestingly also softened at subsaturation densities. In addition, the softening of the symmetry energy at subsaturation densities can be partly suppressed by the nonlinear self-interaction of the {sigma} meson.

  9. Effect of asymmetrical street aspect ratios on microclimates in hot, humid regions

    NASA Astrophysics Data System (ADS)

    Qaid, Adeb; Ossen, Dilshan R.

    2015-06-01

    Asymmetrical street aspect ratios, i.e. different height-to-width (H1/W-H2/W) ratios, have not received much attention in the study of urban climates. Putrajaya Boulevard (northeast to southwest orientation) in Malaysia was selected to study the influence of six asymmetrical aspect ratio scenarios on the street microclimate using the Envi-met three-dimensional microclimate model (V3.1 Beta). Putrajaya Boulevard suffers from high surface and air temperature during the day due to the orientation, the low aspect ratio and the wide sky view factor. These issues are a common dilemma in many boulevards. Further, low and high symmetrical streets are incompatible with tropical regions as they offer conflicting properties during the day and at night. These scenarios are examined, therefore, to find asymmetrical streets which are able to reduce the impact of the day microclimate on boulevards, and as an alternative strategy fulfilling tropical day and night climatic conditions. Asymmetrical streets are better than low symmetrical streets in enhancing wind flow and blocking solar radiation, when tall buildings confront winds direction or solar altitudes. Therefore, mitigating heat islands or improving microclimates in asymmetrical streets based on tall buildings position which captures wind or caste shades. In northeast to southwest direction, aspect ratios of 0.8-2 reduce the morning microclimate and night heat islands yet the negative effects during the day are greater than the positive effects in the night. An aspect ratio of 2-0.8 reduces the temperature of surfaces by 10 to 14 °C and the air by 4.7 °C, recommended for enhancing boulevard microclimates and mitigating tropical heat islands.

  10. Effect of asymmetrical street aspect ratios on microclimates in hot, humid regions.

    PubMed

    Qaid, Adeb; Ossen, Dilshan R

    2015-06-01

    Asymmetrical street aspect ratios, i.e. different height-to-width (H1/W-H2/W) ratios, have not received much attention in the study of urban climates. Putrajaya Boulevard (northeast to southwest orientation) in Malaysia was selected to study the influence of six asymmetrical aspect ratio scenarios on the street microclimate using the Envi-met three-dimensional microclimate model (V3.1 Beta). Putrajaya Boulevard suffers from high surface and air temperature during the day due to the orientation, the low aspect ratio and the wide sky view factor. These issues are a common dilemma in many boulevards. Further, low and high symmetrical streets are incompatible with tropical regions as they offer conflicting properties during the day and at night. These scenarios are examined, therefore, to find asymmetrical streets which are able to reduce the impact of the day microclimate on boulevards, and as an alternative strategy fulfilling tropical day and night climatic conditions. Asymmetrical streets are better than low symmetrical streets in enhancing wind flow and blocking solar radiation, when tall buildings confront winds direction or solar altitudes. Therefore, mitigating heat islands or improving microclimates in asymmetrical streets based on tall buildings position which captures wind or caste shades. In northeast to southwest direction, aspect ratios of 0.8-2 reduce the morning microclimate and night heat islands yet the negative effects during the day are greater than the positive effects in the night. An aspect ratio of 2-0.8 reduces the temperature of surfaces by 10 to 14 °C and the air by 4.7 °C, recommended for enhancing boulevard microclimates and mitigating tropical heat islands. PMID:25108376

  11. Synergistic Effect between Ultra-Small Nickel Hydroxide Nanoparticles and Reduced Graphene Oxide sheets for the Application in High-Performance Asymmetric Supercapacitor

    PubMed Central

    Liu, Yonghuan; Wang, Rutao; Yan, Xingbin

    2015-01-01

    Nanoscale electrode materials including metal oxide nanoparticles and two-dimensional graphene have been employed for designing supercapacitors. However, inevitable agglomeration of nanoparticles and layers stacking of graphene largely hamper their practical applications. Here we demonstrate an efficient co-ordination and synergistic effect between ultra-small Ni(OH)2 nanoparticles and reduced graphene oxide (RGO) sheets for synthesizing ideal electrode materials. On one hand, to make the ultra-small Ni(OH)2 nanoparticles work at full capacity as an ideal pseudocapacitive material, RGO sheets are employed as an suitable substrate to anchor these nanoparticles against agglomeration. As a consequence, an ultrahigh specific capacitance of 1717 F g−1 at 0.5 A g−1 is achieved. On the other hand, to further facilitate ion transfer within RGO sheets as an ideal electrical double layer capacitor material, the ultra-small Ni(OH)2 nanoparticles are introduced among RGO sheets as the recyclable sacrificial spacer to prevent the stacking. The resulting RGO sheets exhibit superior rate capability with a high capacitance of 182 F g−1 at 100 A g−1. On this basis, an asymmetric supercapacitor is assembled using the two materials, delivering a superior energy density of 75 Wh kg−1 and an ultrahigh power density of 40 000 W kg−1. PMID:26053847

  12. Synergistic Effect between Ultra-Small Nickel Hydroxide Nanoparticles and Reduced Graphene Oxide sheets for the Application in High-Performance Asymmetric Supercapacitor

    NASA Astrophysics Data System (ADS)

    Liu, Yonghuan; Wang, Rutao; Yan, Xingbin

    2015-06-01

    Nanoscale electrode materials including metal oxide nanoparticles and two-dimensional graphene have been employed for designing supercapacitors. However, inevitable agglomeration of nanoparticles and layers stacking of graphene largely hamper their practical applications. Here we demonstrate an efficient co-ordination and synergistic effect between ultra-small Ni(OH)2 nanoparticles and reduced graphene oxide (RGO) sheets for synthesizing ideal electrode materials. On one hand, to make the ultra-small Ni(OH)2 nanoparticles work at full capacity as an ideal pseudocapacitive material, RGO sheets are employed as an suitable substrate to anchor these nanoparticles against agglomeration. As a consequence, an ultrahigh specific capacitance of 1717 F g-1 at 0.5 A g-1 is achieved. On the other hand, to further facilitate ion transfer within RGO sheets as an ideal electrical double layer capacitor material, the ultra-small Ni(OH)2 nanoparticles are introduced among RGO sheets as the recyclable sacrificial spacer to prevent the stacking. The resulting RGO sheets exhibit superior rate capability with a high capacitance of 182 F g-1 at 100 A g-1. On this basis, an asymmetric supercapacitor is assembled using the two materials, delivering a superior energy density of 75 Wh kg-1 and an ultrahigh power density of 40 000 W kg-1.

  13. Synergistic Effect between Ultra-Small Nickel Hydroxide Nanoparticles and Reduced Graphene Oxide sheets for the Application in High-Performance Asymmetric Supercapacitor.

    PubMed

    Liu, Yonghuan; Wang, Rutao; Yan, Xingbin

    2015-01-01

    Nanoscale electrode materials including metal oxide nanoparticles and two-dimensional graphene have been employed for designing supercapacitors. However, inevitable agglomeration of nanoparticles and layers stacking of graphene largely hamper their practical applications. Here we demonstrate an efficient co-ordination and synergistic effect between ultra-small Ni(OH)2 nanoparticles and reduced graphene oxide (RGO) sheets for synthesizing ideal electrode materials. On one hand, to make the ultra-small Ni(OH)2 nanoparticles work at full capacity as an ideal pseudocapacitive material, RGO sheets are employed as an suitable substrate to anchor these nanoparticles against agglomeration. As a consequence, an ultrahigh specific capacitance of 1717 F g(-1) at 0.5 A g(-1) is achieved. On the other hand, to further facilitate ion transfer within RGO sheets as an ideal electrical double layer capacitor material, the ultra-small Ni(OH)2 nanoparticles are introduced among RGO sheets as the recyclable sacrificial spacer to prevent the stacking. The resulting RGO sheets exhibit superior rate capability with a high capacitance of 182 F g(-1) at 100 A g(-1). On this basis, an asymmetric supercapacitor is assembled using the two materials, delivering a superior energy density of 75 Wh kg(-1) and an ultrahigh power density of 40 000 W kg(-1). PMID:26053847

  14. The Inhibitory Effect of Quercetin on Asymmetric Dimethylarginine-Induced Apoptosis Is Mediated by the Endoplasmic Reticulum Stress Pathway in Glomerular Endothelial Cells

    PubMed Central

    Guo, Weikang; Ding, Jiaxiang; Zhang, Aihua; Dai, Wendi; Liu, Sha; Diao, Zongli; Wang, Liyan; Han, Xue; Liu, Wenhu

    2014-01-01

    Asymmetric dimethylarginine (ADMA) is considered an independent mortality and cardiovascular risk factor in chronic kidney disease (CKD) patients, and contributes to the development of renal fibrosis. Quercetin (QC), a natural component of foods, protects against renal injury. Here, we explored the possible mechanisms that are responsible for ADMA-induced renal fibrosis and the protective effect of QC. We found that ADMA treatment activated the endoplasmic reticulum (ER) stress sensor proteins phosphorylated protein kinase RNA-activated-like ER kinase (PERK) and inositol requiring-1α (IRE1), which correspondingly induced C/EBP homologous protein (CHOP) expression and phosphorylated c-Jun N-terminal kinase (JNK) phosphorylation in glomerular endothelial cells (GEnCs). Following this, ADMA promoted ER stress-induced apoptosis and resulted in transforming growth factor β (TGF-β) expression in GEnCs. SP600125, an inhibitor of JNK, and CHOP siRNA protected against ADMA-induced cell apoptosis and TGF-β expression. QC prevented ADMA-induced PERK and IRE1 apoptotic ER stress pathway activation. Also, ADMA-induced GEnCs apoptosis and TGF-β expression was reduced by QC. Overexpression of CHOP blocked QC-mediated protection from apoptosis in ER stressed cells. Overall, these observations indicate that ADMA may induce GEnCs apoptosis and TGF-β expression by targeting the PERK-CHOP and IRE1-JNK pathway. In addition, drugs such as QC targeting ER stress may hold great promise for the development of novel therapies against ADMA-induced renal fibrosis. PMID:24451129

  15. Asymmetric Planetary Nebulae VI: the conference summary

    NASA Astrophysics Data System (ADS)

    De Marco, O.

    2014-04-01

    The Asymmetric Planetary Nebulae conference series, now in its sixth edition, aims to resolve the shaping mechanism of PN. Eighty percent of PN have non spherical shapes and during this conference the last nails in the coffin of single stars models for non spherical PN have been put. Binary theories abound but observational tests are lagging. The highlight of APN6 has been the arrival of ALMA which allowed us to measure magnetic fields on AGB stars systematically. AGB star halos, with their spiral patterns are now connected to PPN and PN halos. New models give us hope that binary parameters may be decoded from these images. In the post-AGB and pre-PN evolutionary phase the naked post-AGB stars present us with an increasingly curious puzzle as complexity is added to the phenomenologies of objects in transition between the AGB and the central star regimes. Binary central stars continue to be detected, including the first detection of longer period binaries, however a binary fraction is still at large. Hydro models of binary interactions still fail to give us results, if we make an exception for the wider types of binary interactions. More promise is shown by analytical considerations and models driven by simpler, 1D simulations such as those carried out with the code MESA. Large community efforts have given us more homogeneous datasets which will yield results for years to come. Examples are the ChanPlaN and HerPlaNe collaborations that have been working with the Chandra and Herschel space telescopes, respectively. Finally, the new kid in town is the intermediate-luminosity optical transient, a new class of events that may have contributed to forming several peculiar PN and pre-PN.

  16. Asymmetric field-aligned currents in the conjugate hemispheres

    NASA Astrophysics Data System (ADS)

    Reistad, J. P.; Ostgaard, N.; Oksavik, K.; Laundal, K. M.

    2012-12-01

    Earlier studies using simultaneous imaging from space of the Aurora Borealis (Northern Hemisphere) and Aurora Australis (Southern Hemisphere) have revealed that the aurora can experience a high degree of asymmetry between the two hemispheres. Using 19 hours of simultaneous global imaging from both hemispheres (IMAGE satellite in north and Polar satellite in south) in conjunction with the entire IMAGE WIC database, we investigate the importance of various mechanisms thought to generate the asymmetries seen in global imaging. In terms of asymmetric or interhemispheric field-aligned currents, three candidate mechanisms have been suggested: 1) Hemispheric differences in solar wind dynamo efficiency mainly controlled by IMF Bx leading to asymmetric region 1 currents; 2) conductivity differences in conjugate areas; and 3) penetration of IMF By into the closed magnetosphere possibly generating a pair of oppositely directed interhemispheric currents. From the 19 hour conjugate dataset we find that the solar wind dynamo is likely to be the most important controlling mechanism for asymmetric bright aurora in the polar part of the nightside oval. Here we present statistical analyses of candidates 1) and 3). Using the entire IMAGE WIC database, a statistical analysis of the auroral brightness distribution along and across the Northern Hemisphere oval is carried out. For each candidate, two extreme cases (+/- IMF Bx for 1) and +/- IMF By for 3)) are compared during times non-favorable for the other two mechanisms. Our results indicate that solar wind dynamo induced currents play an important role for the nightside auroral brightness in an average sense. Also, signatures of interhemispheric currents due to IMF By penetration are seen in our statistics, although this effect is somehow weaker.

  17. The Asymmetrical "Sticking" Behavior of Two Balls on an Incline.

    ERIC Educational Resources Information Center

    Mallinckrodt, A. John

    1999-01-01

    Offers a relatively simple analysis of the asymmetrical "sticking" and rolling behavior of two balls, one steel and one rubber, on an incline. Describes an Interactive Physics (TM) simulation designed to study the problem and gives rough experimental results. (WRM)

  18. Effect of biological/physical stimulation on guided bone regeneration through asymmetrically porous membrane.

    PubMed

    Kim, Tae Ho; Oh, Se Heang; Na, Seung Yeon; Chun, So Young; Lee, Jin Ho

    2012-06-01

    Asymmetrically porous polycaprolactone (PCL)/Pluronic F127 guided bone regeneration (GBR) membranes were fabricated. The top surface of the membrane had nanosize pores (∼10 nm) which can effectively prevent invasion by fibrous connective tissue but permeate nutrients, whereas the bottom surface had microsize pores (∼200 μm) which can enhance the adhesiveness with bone tissue. Ultrasound was applied to a bone morphogenetic protein (BMP-2)-immobilized PCL/F127 GBR membrane to investigate the feasibility of using dual biological (BMP-2) and physical (ultrasound) stimulation for enhancing bone regeneration through the membrane. In an animal study using SD rats (cranial defect model), the bone regeneration behavior that occurred when using BMP-2-loaded GBR membranes with ultrasound treatment (GBR/BMP-2/US) was much faster than when the same GBR membrane was used without the ultrasound treatment (GBR/BMP-2), as well as when GBR membranes were used without stimulations (GBR). The enhanced bone regeneration of the GBR/BMP-2/US group can be interpreted as resulting from the synergistic or additive effect of the asymmetrically porous PCL/F127 membrane with unique properties (selective permeability, hydrophilicity, and osteoconductivity) and the stimulatory effects of BMP-2 and ultrasound (osteoinductivity). The asymmetrically porous GBR membrane with dual BMP-2 and ultrasound stimulation may be promising for the clinical treatment of delayed and insufficient bone healing. PMID:22408081

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

    NASA Astrophysics Data System (ADS)

    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.

  20. The effects of asymmetric vs. symmetric probability of targets following probe and irrelevant stimuli in the complex trial protocol for detection of concealed information with P300.

    PubMed

    Rosenfeld, J Peter; Tang, Monica; Meixner, John; Winograd, Michael; Labkovsky, Elena

    2009-08-01

    The complex trial protocol (CTP, [J.P. Rosenfeld, E. Labkovsky, M. Winograd, M.A. Lui, C. Vandenboom & E. Chedid (2008), The complex trial protocol (CTP): a new, countermeasure-resistant, accurate P300-based method for detection of concealed information. Psychophysiology, 45, 906-919.]) is a sensitive, new, countermeasure-resistant, P300-based concealed information protocol in which a first stimulus (Probe or Irrelevant) is followed after about 1.4-1.8 s by a Target or Non-Target second stimulus within one trial. It has been previously run with a potentially confounding asymmetric conditional probability of Targets following Probes vs. Irrelevants. This present study compared asymmetric vs. symmetric conditional probability groups and found no significant differences in detection rates or Probe-minus-Irrelevant P300 differences between groups. Group differences were seen in error rates and reaction times (RT) to second stimuli. These differences were, however, not diagnostic for deception vs. truth-telling, and were attributable to response perseveration. PMID:19374912

  1. Asymmetric and Negative Differential Thermal Spin Effect at Magnetic Interfaces: Towards Spin Seebeck Diodes and Transistors

    NASA Astrophysics Data System (ADS)

    Ren, Jie; Zhu, Jian-Xin

    2014-03-01

    We study the nonequilibrium thermal-spin transport across metal-magnetic insulator interfaces. The transport is assisted by the exchange interaction between conduction electrons in the metal and localized spins in the magnetic insulator. We predict the rectification and negative differential spin Seebeck effect (SSE), that is, reversing the temperature bias is able to give asymmetric spin currents and increasing temperature bias could give an anomalously decreasing spin current. We resolve their microscopic mechanism as a consequence of the energy-dependent electronic DOS in the metal. The rectification of spin Peltier effect is also discussed. We then study the asymmetric and negative differential magnon tunneling driven by temperature bias. We show that the many-body magnon interaction that makes the magnonic spectrum temperature-dependent is the crucial factor for the emergence of rectification and negative differential SSEs in magnon tunneling junctions. We show that these asymmetric and negative differential SSEs are relevant for building magnon and spin Seebeck diodes and transistors, which could play important roles in controlling information and energy in functional devices. Supported by the National Nuclear Security Administration of the US DOE at LANL under Contract No. DE-AC52-06NA25396.

  2. Coupled effects of market impact and asymmetric sensitivity in financial markets

    NASA Astrophysics Data System (ADS)

    Zhong, Li-Xin; Xu, Wen-Juan; Ren, Fei; Shi, Yong-Dong

    2013-05-01

    By incorporating market impact and asymmetric sensitivity into the evolutionary minority game, we study the coevolutionary dynamics of stock prices and investment strategies in financial markets. Both the stock price movement and the investors’ global behavior are found to be closely related to the phase region they fall into. Within the region where the market impact is small, investors’ asymmetric response to gains and losses leads to the occurrence of herd behavior, when all the investors are prone to behave similarly in an extreme way and large price fluctuations occur. A linear relation between the standard deviation of stock price changes and the mean value of strategies is found. With full market impact, the investors tend to self-segregate into opposing groups and the introduction of asymmetric sensitivity leads to the disappearance of dominant strategies. Compared with the situations in the stock market with little market impact, the stock price fluctuations are suppressed and an efficient market occurs. Theoretical analyses indicate that the mechanism of phase transition from clustering to self-segregation in the present model is similar to that in the majority-minority game and the occurrence and disappearance of efficient markets are related to the competition between the trend-following and the trend-aversion forces. The clustering of the strategies in the present model results from the majority-wins effect and the wealth-driven mechanism makes the market become predictable.

  3. Modeling the Overalternating Bias with an Asymmetric Entropy Measure.

    PubMed

    Gronchi, Giorgio; Raglianti, Marco; Noventa, Stefano; Lazzeri, Alessandro; Guazzini, Andrea

    2016-01-01

    Psychological research has found that human perception of randomness is biased. In particular, people consistently show the overalternating bias: they rate binary sequences of symbols (such as Heads and Tails in coin flipping) with an excess of alternation as more random than prescribed by the normative criteria of Shannon's entropy. Within data mining for medical applications, Marcellin proposed an asymmetric measure of entropy that can be ideal to account for such bias and to quantify subjective randomness. We fitted Marcellin's entropy and Renyi's entropy (a generalized form of uncertainty measure comprising many different kinds of entropies) to experimental data found in the literature with the Differential Evolution algorithm. We observed a better fit for Marcellin's entropy compared to Renyi's entropy. The fitted asymmetric entropy measure also showed good predictive properties when applied to different datasets of randomness-related tasks. We concluded that Marcellin's entropy can be a parsimonious and effective measure of subjective randomness that can be useful in psychological research about randomness perception. PMID:27458418

  4. Modeling the Overalternating Bias with an Asymmetric Entropy Measure

    PubMed Central

    Gronchi, Giorgio; Raglianti, Marco; Noventa, Stefano; Lazzeri, Alessandro; Guazzini, Andrea

    2016-01-01

    Psychological research has found that human perception of randomness is biased. In particular, people consistently show the overalternating bias: they rate binary sequences of symbols (such as Heads and Tails in coin flipping) with an excess of alternation as more random than prescribed by the normative criteria of Shannon's entropy. Within data mining for medical applications, Marcellin proposed an asymmetric measure of entropy that can be ideal to account for such bias and to quantify subjective randomness. We fitted Marcellin's entropy and Renyi's entropy (a generalized form of uncertainty measure comprising many different kinds of entropies) to experimental data found in the literature with the Differential Evolution algorithm. We observed a better fit for Marcellin's entropy compared to Renyi's entropy. The fitted asymmetric entropy measure also showed good predictive properties when applied to different datasets of randomness-related tasks. We concluded that Marcellin's entropy can be a parsimonious and effective measure of subjective randomness that can be useful in psychological research about randomness perception. PMID:27458418

  5. Asymmetric distribution of a fluorescent sterol in synaptic plasma membranes: effects of chronic ethanol consumption.

    PubMed

    Wood, W G; Schroeder, F; Hogy, L; Rao, A M; Nemecz, G

    1990-06-27

    Ethanol-induced structural changes in membranes have in some studies been attributed to an increase in total membrane cholesterol. Consistent changes in cholesterol content, however, have not been observed in membranes of ethanol consuming animals and alcoholic patients. This study examined the hypotheses that cholesterol was asymmetrically distributed in synaptic plasma membranes (SPM) and that chronic ethanol consumption alters the transbilayer distribution of cholesterol. Dehydroergosterol, a fluorescent cholesterol analogue was used to examine sterol distribution and exchange in chronic ethanol-treated and pair-fed control groups. The cytofacial leaflet was found to have significantly more dehydroergosterol as compared to the exofacial leaflet. This asymmetric distribution was significantly reduced by chronic ethanol consumption as was sterol transport. Total cholesterol content did not differ between the two groups. Chronic ethanol consumption appeared to alter transbilayer sterol distribution as determined by the incorporation and distribution of dehydroergosterol in SPM. The changes in transbilayer sterol distribution are consistent with recent reports on the asymmetric effects of ethanol in vitro ((1988) Biochim. Biophys. Acta 946, 85-94) and in vivo ((1989) J. Neurochem. 52, 1925-1930) on membrane leaflet structure. The results of this study also underscore the importance of examining membrane lipid domains in addition to the total content of different lipids. PMID:2364080

  6. The Sharpless Asymmetric Dihydroxylation in the Organic Chemistry Majors Laboratory

    ERIC Educational Resources Information Center

    Nicholas, Christopher J.; Taylor, Melissa R.

    2005-01-01

    Sharpless asymmetric dihydroxylation is developed that focuses on the varying enantiomeric excess of the product diols based on the structures of the alkenes being oxidized. The experimental sequence enables investigation of this reaction in terms of the different chiral ligands being used.

  7. Suppression of the asymmetric modes for experimentally achieving gigawatt-level radiation from a Ku-band Cerenkov type oscillator.

    PubMed

    Zhang, Hua; Shu, Ting; Ju, Jinchuan; Wu, Dapeng; Bai, Zhen

    2014-08-01

    We present the analysis and suppression of asymmetric modes in a Ku-band Cerenkov-type oscillator numerically and experimentally. The asymmetric modes generated in the initial experiments were identified to be HE11, HE21, and HE31 modes, respectively, by analyzing of the dispersion relationships, the simulation results and the experiment phenomenon. The factors, such as the cathode emission uniformity, the diode voltage, guiding magnetic field, and the concentricity play key roles in the excitation and suppression of these asymmetric modes. In the improved experiments, the asymmetric modes were suppressed effectively. In the improved experiments the asymmetric modes are suppressed effectively, and the designed TM01 mode microwave is generated at a frequency of 13.76 GHz with a power of 1.1 GW, which is in good agreement with numerically predications. PMID:25173289

  8. Graphene field effect transistors with niobium contacts and asymmetric transfer characteristics.

    PubMed

    Bartolomeo, Antonio Di; Giubileo, Filippo; Romeo, Francesco; Sabatino, Paolo; Carapella, Giovanni; Iemmo, Laura; Schroeder, Thomas; Lupina, Grzegorz

    2015-11-27

    We fabricate back-gated field effect transistors using niobium electrodes on mechanically exfoliated monolayer graphene and perform electrical characterization in the pressure range from atmospheric down to 10(-4) mbar. We study the effect of room temperature vacuum degassing and report asymmetric transfer characteristics with a resistance plateau in the n-branch. We show that weakly chemisorbed Nb acts as p-dopant on graphene and explain the transistor characteristics by Nb/graphene interaction with unpinned Fermi level at the interface. PMID:26535591

  9. The Influence of the Asymmetric Ionosphere on the Schumann Resonances

    NASA Astrophysics Data System (ADS)

    Yu, H.; Williams, E. R.

    2015-12-01

    The asymmetric ionosphere is known to affect the behavior of the Earth's Schumann resonances (SR). Several studies have addressed the day-night asymmetry with observation or simulation and showed the contrast in SR amplitude between day and night (Satori et.al 2007, Pechony and Price 2007, Yang et.al., 2006). And distinct perturbations in the ionosphere caused by solar proton events, x-ray emission and earthquake coupling will also produce variations in SRs (Roldugin et.al., 2004, De et al., 2010; Satori et.al., 2015). Considering all these possible variations produced by changes in ionospheric asymmetry, we simulate the SR propagation in an asymmetric cavity including the day-night contribution and the more general perturbation asymmetry using a TDTE (Two Dimensional Telegraph Equation) approach. The change of source position in the asymmetric ionosphere and the size of the perturbation will also affect the SR parameters such as amplitude and modal frequency. The central location of the source in either the daytime or nighttime zone will produce a larger amplitude than other locations in the cavity. For example, the amplitude from a source in the zone with lower electric height (like the daytime region) is larger than the situation with source in region of larger electric height (like nighttime region). The asymmetry(difference on EM amplitude between two regions) will be more distinct when the source is on the terminator between two region than on other position. And when the size of the asymmetric construction is changed, the amplitude and modal frequency will also be changed. The increased size of the zone with lower electric height will produce larger SR amplitudes and decreased modal frequency.

  10. Continuous Flavor Symmetries and the Stability of Asymmetric Dark Matter

    SciTech Connect

    Bishara, Fady; Zupan, Jure

    2015-01-19

    Generically, the asymmetric interactions in asymmetric dark matter (ADM) models could lead to decaying DM. We show that, for ADM that carries nonzero baryon number, continuous flavor symmetries that generate the flavor structure in the quark sector also imply a looser lower bound on the mass scale of the asymmetric mediators between the dark and visible sectors. Furthermore, the mediators for B = 2 ADM that can produce a signal in the future indirect dark matter searches can thus also be searched for at the LHC. For two examples of the mediator models, with either the MFV or Froggatt-Nielsen flavor breaking pattern, we derive the FCNC constraints and discuss the search strategies at the LHC.

  11. Continuous Flavor Symmetries and the Stability of Asymmetric Dark Matter

    DOE PAGESBeta

    Bishara, Fady; Zupan, Jure

    2015-01-19

    Generically, the asymmetric interactions in asymmetric dark matter (ADM) models could lead to decaying DM. We show that, for ADM that carries nonzero baryon number, continuous flavor symmetries that generate the flavor structure in the quark sector also imply a looser lower bound on the mass scale of the asymmetric mediators between the dark and visible sectors. Furthermore, the mediators for B = 2 ADM that can produce a signal in the future indirect dark matter searches can thus also be searched for at the LHC. For two examples of the mediator models, with either the MFV or Froggatt-Nielsen flavormore » breaking pattern, we derive the FCNC constraints and discuss the search strategies at the LHC.« less

  12. Probing asymmetric structures in the outskirts of galaxies

    SciTech Connect

    Wen, Zhang Zheng; Zheng, Xian Zhong; An, Fang Xia E-mail: xzzheng@pmo.ac.cn

    2014-06-01

    Upcoming large imaging surveys will allow detailed studies of the structure and morphology of galaxies aimed at addressing how galaxies form and evolve. Computational approaches are needed to characterize their morphologies over large samples. We introduce an automatic method to quantify the outer structure of galaxies. The key to our approach is the division of a galaxy image into two sections delineated by the isophote, which encloses half the total brightness of the galaxy. We call the central section the inner half-flux region (IHR) and the outer section the outer half-flux region (OHR). From this division, we derive two parameters: A {sub o}, which measures the asymmetry of the OHR, and D {sub o}, which measures the deviation of the intensity weighted centroid of the OHR from that of the IHR relative to the effective radius. We derive the two parameters from HST/ACS z {sub 850}-band images for a sample of 764 galaxies with z {sub 850} < 22 mag and 0.35 < z < 0.9 selected from the GEMS and GOODS-South surveys. We show that the sample galaxies having strong asymmetric structures, particularly tidal tails, are well-separated from those with regular morphologies in the A {sub o}-D {sub o} space. Meanwhile, the widely used CAS and Gini-M {sub 20} methods turn out to be insensitive to such morphological features. We stress that the A {sub o}-D {sub o} method is an efficient way to select galaxies with significant asymmetric features like tidal tails and study galaxy mergers in the dynamical phase traced by these delicate features.

  13. Paramagnetic Meissner effect and finite spin susceptibility in an asymmetric superconductor

    SciTech Connect

    He Lianyi; Jin Meng; Zhuang Pengfei

    2006-01-01

    A general analysis of Meissner effect and spin susceptibility of a uniform superconductor in an asymmetric two-component fermion system is presented in nonrelativistic field theory approach. We found that the pairing mechanism dominates the magnetization property of superconductivity and the asymmetry enhances the paramagnetism of the system. At the turning point from BCS to breached pairing superconductivity, the Meissner mass squared and spin susceptibility are divergent at zero temperature. In the breached pairing state induced by chemical potential difference and mass difference between the two kinds of fermions, the system goes from paramagnetism to diamagnetism, when the mass ratio of the two species increases.

  14. Strongly asymmetric discrete Painlevé equations: The multiplicative case

    NASA Astrophysics Data System (ADS)

    Grammaticos, B.; Ramani, A.; Tamizhmani, K. M.; Tamizhmani, T.; Satsuma, J.

    2016-04-01

    We examine a class of multiplicative discrete Painlevé equations which may possess a strongly asymmetric form. When the latter occurs, the equation is written as a system of two equations the right hand sides of which have different functional forms. The present investigation focuses upon two canonical families of the Quispel-Roberts-Thompson classification which contain equations associated with the affine Weyl groups D5 ( 1 ) and E6 ( 1 ) (or groups appearing lower in the degeneration cascade of these two). Many new discrete Painlevé equations with strongly asymmetric forms are obtained.

  15. Preliminary investigation of the effects of lower hybrid power on asymmetric behaviors in the scrape-off layer in experimental advanced superconducting tokamak

    SciTech Connect

    Zhang, L.; Ding, B. J. Li, M. H.; Liu, F. K.; Shan, J. F.; Wei, W.; Li, Y. C.; Yang, J. H.; Wu, Z. G.; Liu, L.; Wang, M.; Zhao, L. M.; Ma, W. D.; Xiu, H. D.; Wang, X. J.; Jia, H.; Yang, Y.; Cheng, M.; Wu, D. J.; Xu, L.; and others

    2014-02-15

    The striations in front of the lower hybrid (LH) launcher have been observed during LH injection by a visible video camera in the Experimental Advanced Superconducting Tokamak. Edge density at the top of the LH launcher tends to be much larger in reversed magnetic field (B{sub t}) than that in the normal B{sub t}. To study the mechanisms of the observations, the diffusive-convective model is employed. Simulations show that the LH power makes the density in scrape-off layer asymmetric in poloidal direction with five density peaks. The locations of the striations are approximately in agreement with the locations of the density peaks in different directions of B{sub t}. Higher LH power strengths the asymmetry of the density and leads to a bad coupling which is in conflict with the experimental results showing a good coupling with a higher power. Furthermore, an ionization term is introduced into this model and the increase of edge density with LH power can be qualitatively explained. The simulations also show that the density peaks in front of the waveguides become clearer when taking into account gas puffing.

  16. The Mediastinal Waltz--A Representation of Asymmetrical Mediastinal Anatomy

    ERIC Educational Resources Information Center

    Chan, Lap Ki

    2011-01-01

    Many structures in the mediastinum have asymmetrical relationships. For example, the pulmonary artery is superior to the main bronchus on the left side but is anterior on the right side. The pulmonary trunk is not in the midline, but to the left of the midline, and bifurcates anterior to the left main bronchus. Students often find these…

  17. Strong Asymmetric Coupling of Two Parallel Exclusion Processes: Effect of Unequal Injection Rates

    NASA Astrophysics Data System (ADS)

    Xiao, Song; Dong, Peng; Zhang, Yingjie; Liu, Yanna

    2016-03-01

    In this letter, strong asymmetric coupling of two parallel exclusion processes: effect of unequal injection rates will be investigated. It is a generalization of the work of Xiao et al. (Phys. Lett. A 8, 374 (2009)), in which the particles only move on two lanes with rate 1 toward right. We can obtain the diverse phase diagram and density profiles of the system. The vertical cluster mean-field approach and extensively Monte Carlo simulations are used to study the system, and theoretical predictions are in excellent agreement with simulation results.

  18. Model-size reduction for the analysis of symmetric structures with asymmetric boundary conditions

    NASA Technical Reports Server (NTRS)

    Noor, Ahmed K.; Whitworth, Sandra L.

    1987-01-01

    A simple computational procedure is presented for reducing the size of the analysis model for a symmetric structure with asymmetric boundary conditions to that of the corresponding structure with symmetric boundary conditions. The procedure is based on approximating the asymmetric response of the structure by a linear combination of symmetric and antisymmetric global approximation vectors (or modes). The key elements of the procedure are (1) restructuring the governing finite-element equations to delineate the contributions to the symmetric and antisymmetric components of the asymmetric response, (2) successive application of the finite element method and the classical Rayleigh-Ritz technique. The finite-element method is first used to generate a few global approximation vectors (or modes). Then the amplitudes of these modes are computed by using the Rayleigh-Ritz technique. The effectiveness of the computational procedure is demonstrated by means of numerical examples of linear static problems of shells, and its potential for solving nonlinear problems is discussed.

  19. Reconstruction of the Asymmetric Magnetic Reconnection Region at the Magnetopause

    NASA Astrophysics Data System (ADS)

    Guo, R.; Pu, Z.; Xie, L.; Fu, S.

    2015-12-01

    Magnetic reconnection at the magnetopause is a key process coupling the earth's magnetosphere with interplanetary space. Multiple spacecraft measurement makes it possible to study observationally the structure of the reconnection region. In this paper we improve the fitting-reconstructing method developed by He et al. [2008] and use it to investigate the asymmetric reconnection event observed by Cluster on Apr. 06, 2004. The reconnection site was encountered when the constellation traversed the dayside magnetopause at z~5.3Re, with spacecraft separations less than 400km. The reconstructing results clearly revealed the asymmetric geometry of the reconnection region. The orientation of the X-line, which was reproduced as the separator linking a pair of magnetic null points, was shown to be ~60° away from the M-direction in the local LMN coordinate. Bipolar and unipolar Hall fields were both seen by different spacecraft, implying that the reconnection regime was 3D in nature, and the difference in Hall fields could be related to the existence of two null points which restricted the length of the separator. In addition, electromagnetic lower hybrid waves are found to be enhanced on the magnetospheric side of the reconnection region. The reconstructing results are helpful for providing a 3D picture of the asymmetric reconnection region, and the improved reconstructing method can be applied to analyze the data from MMS which is deployed with small separations of satellites.

  20. The impact of asymmetric flows on pathological speech

    NASA Astrophysics Data System (ADS)

    Erath, Byron D.; Peterson, Sean D.; Plesniak, Michael W.

    2010-11-01

    In voiced speech the vocal folds form a divergent glottal passage during the closing phases of the phonatory cycle. Due to the adverse pressure gradient, asymmetric flow develops within the glottis causing the glottal jet to separate from one vocal fold wall, and fully-attach to the opposing wall. The asymmetric pressures that arise from this flow configuration directly influence the vocal fold energy exchange process, and are expected to have the greatest influence on vocal fold motion when pathologies that affect the vocal fold musculature are present. A theoretical flow solution that produces the pressure distributions arising from asymmetric glottal flows is implemented into a two-mass model of speech. The impact of flow asymmetries on pathological vocal fold motion is investigated by modifying the tissue parameters of the speech model to represent unilateral paralysis. The influence of asymmetric flow behavior on pathological vocal fold motion is quantified and compared to the commonly-reported simplified case involving symmetric flow behavior.

  1. Asymmetric gravitational spreading - Analogue experiments on the Svecofennian orogen

    NASA Astrophysics Data System (ADS)

    Nikkilä, Kaisa; Korja, Annakaisa; Koyi, Hemin; Eklund, Olav

    2015-04-01

    Over-thickened orogenic crust may suffer from rheological, gravitational and topographical unbalancing resulting in discharging via gravitational spreading. If the thickened orogen is also hot, then increased temperature may reduce the viscosity of the crust that may induce large-scale horizontal flow. The effect of flow on the crustal architecture has previously been modeled with symmetric two-way spreading or asymmetric one- or two-way spreading (like channel flow) experiments. Most models do not take into account of the contrasting mechanical properties of the juxtaposed terranes. We have made analogue experiments to study gravitational one-way spreading and the interplay between two crustal blocks with contrasting rheological properties. The models are 3 cm thick replicas of 60 km thick crust. They have three horizontal layers representing strong lower, weak middle and brittle upper crust. The models have cuts to study the effect of inherited crustal-scale weakness zones. The experiments have been conducted within a large centrifuge in the Hans Ramberg Tectonic Laboratory at Uppsala University. The analogue models propose that asymmetric, unilateral flow has different effect on the contrasting crustal units, in both horizontal and vertical directions. The laterally heterogeneous crust flows towards the direction of extension, and it rotates and extends the pre-existing weakness zones. The weakness zones facilitate exhumation and they increase strain rate. The weakness zones split the crust into subblocks, which stretch individually and which may show signatures of compression or rotation. The changes in thickness of the model reflect changes in the layers, which may thin or thicken depending on the mechanical properties of crustal layers. A consequence of this the total amount of flattening is less than the model extension. The results are compared to geophysical and geological data from Precambrian Svecofennian orogen in Fennoscandia. The comparison suggest

  2. Asymmetric synthesis of pyrazoles and pyrazolones employing the reactivity of pyrazolin-5-one derivatives.

    PubMed

    Chauhan, Pankaj; Mahajan, Suruchi; Enders, Dieter

    2015-08-21

    Due to the frequent occurrence of the pyrazole core in many important naturally occurring and synthetic molecules, tremendous efforts have been made for their synthesis. The pyrazolin-5-one derivatives have emerged as the most effective substrates for the synthesis of useful pyrazoles and their corresponding pyrazolone derivatives. Recently, the reactivity of pyrazolin-5-ones has been used for the asymmetric synthesis of highly functionalised pyrazole and pyrazolone derivatives by employing organo- and metal-catalysts. This feature article focuses on the progress in the catalytic asymmetric synthesis of pyrazoles and pyrazolones using pyrazolin-5-one derivatives. PMID:26178319

  3. On the Complexity of the Asymmetric VPN Problem

    NASA Astrophysics Data System (ADS)

    Rothvoß, Thomas; Sanità, Laura

    We give the first constant factor approximation algorithm for the asymmetric Virtual Private Network (textsc{Vpn}) problem with arbitrary concave costs. We even show the stronger result, that there is always a tree solution of cost at most 2·OPT and that a tree solution of (expected) cost at most 49.84·OPT can be determined in polynomial time.

  4. An Organocatalytic Biomimetic Strategy Paves the Way for the Asymmetric Umpolung of Imines.

    PubMed

    Waser, Mario; Novacek, Johanna

    2015-11-23

    Just like Nature: A recently developed enantioselective organocatalytic biomimetic transamination provides an elegant approach towards chiral amines. In the presence of an asymmetric phase-transfer catalyst, the intermediate anionic species undergoes an asymmetric C-C bond-forming reaction in a powerful and broadly applicable asymmetric umpolung strategy. PMID:26461174

  5. Response of the intertropical convergence zone to zonally asymmetric subtropical surface forcings

    NASA Astrophysics Data System (ADS)

    Shaw, Tiffany A.; Voigt, Aiko; Kang, Sarah M.; Seo, Jeongbin

    2015-11-01

    The energetic framework predicts no shift of the zonal mean Intertropical Convergence Zone (ITCZ) in response to zonally asymmetric forcings (zonal warming and cooling regions with zero zonal mean) assuming radiative feedbacks are linear. Here we show the ITCZ shifts southward in response to a zonally asymmetric forcing in the Northern Hemisphere subtropics in a slab ocean aquaplanet model. The southward shift is consistent with decreased zonal mean energy input to the atmosphere due to cloud radiative effect changes in the cooling region. When cloud-radiative feedbacks are disabled the ITCZ shifts northward consistent with changes in the warming region where increased energy input via surface heat fluxes and stationary Rossby-wave transport dominate. Competition between cooling and warming regions leads to changes in gross moist stability. Our results show rectification of zonally asymmetric forcings play an important role in zonal mean ITCZ dynamics and highlight the importance of assessing the momentum budget when interpreting ITCZ shifts.

  6. Effect of delta tabs on mixing and axis switching in jets from asymmetric nozzles

    NASA Technical Reports Server (NTRS)

    Zaman, K. B. M. Q.

    1994-01-01

    The effect of delta tabs on mixing and the phenomenon of axis switching in free air jets from various asymmetric nozzles was studied experimentally. Flow visualization and Pitot probe surveys were carried out with a set of small nozzles (D = 1.47 cm) at a jet Mach number, Mj = 1.63. Hot wire measurements for streamwise vorticity were carried out with larger nozzles (D = 6.35 cm) at Mj = 0.31. Jet mixing with the asymmetric nozzles, as indicated by the mass fluxes downstream, was found to be higher than that produced by a circular nozzle. The circular nozzle with four delta tabs, however, produced fluxes much higher than that produced by a asymmetric nozzles themselves or by most of the tab configurations tried with them. Even higher fluxes could be obtained with only a few cases, e.g., with 3:1 rectangular nozzle with two large delta tabs placed on the narrow edges. In this case, the jet 'fanned out' at a large angle after going through one axis switch. The axis switching could be either stopped or augmented with suitable choice of the tab configurations. Two mechanisms are identified governing the phenomenon. One, as described in Ref. 12 and referred to here as the omega(sub Theta)-induced dynamics, is due to differential induced velocities of different segments of a rolled up azimuthal vortical structure. The other is the omega(sub x)-induced dynamics due to the induced velocities of streamwise vortex pairs in the flow. While the former dynamics are responsible for rapid axis switching in periodically forced jets, the effect of the tabs is governed mainly by the latter. It is inferred that both dynamics are active in a natural asymmetric jet issuing from a nozzle having an upstream contraction. The tendency for axis switching caused by the omega(sub Theta)-induced dynamics is resisted by the omega(sub x)-induced dynamics, leading to a delayed or no switch over in that case. In jets from orifices and in screeching jets, the omega(sub Theta)-induced dynamics

  7. Effect of asymmetric concentration profile on thermal conductivity in Ge/SiGe superlattices

    NASA Astrophysics Data System (ADS)

    Hahn, Konstanze R.; Cecchi, Stefano; Colombo, Luciano

    2016-05-01

    The effect of the chemical composition in Si/Ge-based superlattices on their thermal conductivity has been investigated using molecular dynamics simulations. Simulation cells of Ge/SiGe superlattices have been generated with different concentration profiles such that the Si concentration follows a step-like, a tooth-saw, a Gaussian, and a gamma-type function in direction of the heat flux. The step-like and tooth-saw profiles mimic ideally sharp interfaces, whereas Gaussian and gamma-type profiles are smooth functions imitating atomic diffusion at the interface as obtained experimentally. Symmetry effects have been investigated comparing the symmetric profiles of the step-like and the Gaussian function to the asymmetric profiles of the tooth-saw and the gamma-type function. At longer sample length and similar degree of interdiffusion, the thermal conductivity is found to be lower in asymmetric profiles. Furthermore, it is found that with smooth concentration profiles where atomic diffusion at the interface takes place the thermal conductivity is higher compared to systems with atomically sharp concentration profiles.

  8. Effect of residual attractive interactions in size asymmetric colloidal mixtures: Theoretical analysis and predictions.

    PubMed

    Germain, Ph

    2010-07-28

    We analyze the influence of residual attractions on the static and some dynamic properties of size asymmetric mixtures of "hard-sphere-like" colloids. These attractions, usually neglected in the theoretical analysis, are characterized by a very short range and a moderate strength reflecting the underlying microscopic structure of the colloidal particles. Their effect on the potentials of mean force is analyzed from analytical expressions obtained from low density expansions. The effective potential of the big particle fluid is next considered. An analytical expression is proposed for estimating the deviation with respect to the hard sphere depletion potential. This case is compared to that of mixtures with noninteracting depletants. The important consequences on the binodals and the glass transition lines of the effective fluid are discussed in both cases. This study is next extended to other properties-the specific heat and the low shear viscosity-which incorporate contributions from the two components of the binary mixture. PMID:20687684

  9. Effect of residual attractive interactions in size asymmetric colloidal mixtures: Theoretical analysis and predictions

    NASA Astrophysics Data System (ADS)

    Germain, Ph.

    2010-07-01

    We analyze the influence of residual attractions on the static and some dynamic properties of size asymmetric mixtures of "hard-sphere-like" colloids. These attractions, usually neglected in the theoretical analysis, are characterized by a very short range and a moderate strength reflecting the underlying microscopic structure of the colloidal particles. Their effect on the potentials of mean force is analyzed from analytical expressions obtained from low density expansions. The effective potential of the big particle fluid is next considered. An analytical expression is proposed for estimating the deviation with respect to the hard sphere depletion potential. This case is compared to that of mixtures with noninteracting depletants. The important consequences on the binodals and the glass transition lines of the effective fluid are discussed in both cases. This study is next extended to other properties—the specific heat and the low shear viscosity—which incorporate contributions from the two components of the binary mixture.

  10. The asymmetric segregation of damaged proteins is stem cell-type dependent.

    PubMed

    Bufalino, Mary Rose; DeVeale, Brian; van der Kooy, Derek

    2013-05-13

    Asymmetric segregation of damaged proteins (DPs) during mitosis has been linked in yeast and bacteria to the protection of one cell from aging. Recent evidence suggests that stem cells may use a similar mechanism; however, to date there is no in vivo evidence demonstrating this effect in healthy adult stem cells. We report that stem cells in larval (neuroblast) and adult (female germline and intestinal stem cell) Drosophila melanogaster asymmetrically segregate DPs, such as proteins with the difficult-to-degrade and age-associated 2,4-hydroxynonenal (HNE) modification. Surprisingly, of the cells analyzed only the intestinal stem cell protects itself by segregating HNE to differentiating progeny, whereas the neuroblast and germline stem cells retain HNE during division. This led us to suggest that chronological life span, and not cell type, determines the amount of DPs a cell receives during division. Furthermore, we reveal a role for both niche-dependent and -independent mechanisms of asymmetric DP division. PMID:23649805

  11. Effect of breathing pattern on gas mixing in a model with asymmetrical alveolar ducts.

    PubMed

    Bowes, C L; Richardson, J D; Cumming, G; Horsfield, K

    1985-01-01

    A model of the pulmonary airways was used to study three single-breath indices of gas mixing, dead space (VD), slope of the alveolar plateau, and alveolar mixing inefficiency (AMI). In the model, discrete elements of airway volume were represented by nodes. Using a finite difference technique the differential equation for simultaneous convection and diffusion was solved for the nodal network. Conducting airways and respiratory bronchioles were modeled symmetrically, but alveolar ducts asymmetrically, permitting interaction between convection and diffusion. VD, alveolar slope, and AMI increased with increasing flow. Similar trends were seen with inspired volume, although slope decreased at high inspired volumes with constant flow. VD was affected most by inspiratory flow and AMI and alveolar slope by expiratory time. VD fell approximately exponentially with time of breath holding. Eight different breathing patterns were compared. They had a small effect on alveolar slope and AMI and a greater effect on VD. The model shows how series and parallel inhomogeneity occur together and interact in asymmetrical systems: the old argument as to which is the more important should be abandoned. PMID:3968008

  12. Symmetrical and Asymmetrical Scaffolding of L2 Collocations in the Context of Concordancing

    ERIC Educational Resources Information Center

    Rezaee, Abbas Ali; Marefat, Hamideh; Saeedakhtar, Afsaneh

    2015-01-01

    Collocational competence is recognized to be integral to native-like L2 performance, and concordancing can be of assistance in gaining this competence. This study reports on an investigation into the effect of symmetrical and asymmetrical scaffolding on the collocational competence of Iranian intermediate learners of English in the context of…

  13. Suppression of the asymmetric competition mode in the relativistic Ku-band coaxial transit-time oscillator

    SciTech Connect

    Ling, Junpu; He, Juntao; Zhang, Jiande; Jiang, Tao; Wang, Lei

    2014-10-15

    A relativistic Ku-band coaxial transit-time oscillator has been proposed in our previous work. In the experiments, we find that the asymmetric competition mode in the device limits the microwave power with the increase of the input electric power. For solving such a problem, the methods for analysis and suppression of the asymmetric competition mode in the device are investigated theoretically and experimentally. It is shown that the structure and the material of the collector, the concentricity, and the electron emission uniformity play an important part in the suppression of the asymmetric competition mode in the relativistic Ku-band transit-time oscillator. In the subsequent experiments, the asymmetric mode was suppressed effectively. At a low guiding magnetic field of 0.7 T, a microwave pulse with power of 1 GW, frequency of 14.3 GHz close to the simulation one, and efficiency of 20% was generated.

  14. Magnus-induced ratchet effects for skyrmions interacting with asymmetric substrates

    NASA Astrophysics Data System (ADS)

    Reichhardt, C.; Ray, D.; Olson Reichhardt, C. J.

    2015-07-01

    We show using numerical simulations that pronounced ratchet effects can occur for ac driven skyrmions moving over asymmetric quasi-one-dimensional substrates. We find a new type of ratchet effect called a Magnus-induced transverse ratchet that arises when the ac driving force is applied perpendicular rather than parallel to the asymmetry direction of the substrate. This transverse ratchet effect only occurs when the Magnus term is finite, and the threshold ac amplitude needed to induce it decreases as the Magnus term becomes more prominent. Ratcheting skyrmions follow ordered orbits in which the net displacement parallel to the substrate asymmetry direction is quantized. Skyrmion ratchets represent a new ac current-based method for controlling skyrmion positions and motion for spintronic applications.

  15. Asymmetric-shell ignition capsule design to tune the low-mode asymmetry during the peak drive

    NASA Astrophysics Data System (ADS)

    Gu, Jianfa; Dai, Zhensheng; Song, Peng; Zou, Shiyang; Ye, Wenhua; Zheng, Wudi; Gu, Peijun; Wang, Jianguo; Zhu, Shaoping

    2016-08-01

    The low-mode radiation flux asymmetry in the hohlraum is a main source of performance degradation in the National Ignition Facility (NIF) implosion experiments. To counteract the deleterious effects of the large positive P2 flux asymmetry during the peak drive, this paper develops a new tuning method called asymmetric-shell ignition capsule design which adopts the intentionally asymmetric CH ablator layer or deuterium-tritium (DT) ice layer. A series of two-dimensional implosion simulations have been performed, and the results show that the intentionally asymmetric DT ice layer can significantly improve the fuel ρR symmetry, hot spot shape, hot spot internal energy, and the final neutron yield compared to the spherical capsule. This indicates that the DT asymmetric-shell capsule design is an effective tuning method, while the CH ablator asymmetric-shell capsule could not correct the fuel ρR asymmetry, and it is not as effective as the DT asymmetric-shell capsule design.

  16. Global existence and large time behavior of the asymmetric fluids

    NASA Astrophysics Data System (ADS)

    Tan, Zhong; Tong, Leilei

    2016-06-01

    In this paper, we consider the asymptotic stability of the steady state with the constant equilibrium state. Under the assumptions that the {H^3} norm of the initial data is small, but its higher-order derivatives could be large, we prove the global existence to the Cauchy problem for the asymmetric fluids in {{R}^3}. Moreover, we obtain the time decay rates of the solutions and their higher-order spatial derivatives by introducing the negative Sobolev and Besov spaces.

  17. Left-Right Asymmetric Morphogenesis in the Xenopus Digestive System

    USGS Publications Warehouse

    Muller, Jennifer K.; Prather, D.R.; Nascone-Yoder, N. M.

    2003-01-01

    The morphogenetic mechanisms by which developing organs become left-right asymmetric entities are unknown. To investigate this issue, we compared the roles of the left and right sides of the Xenopus embryo during the development of anatomic asymmetries in the digestive system. Although both sides contribute equivalently to each of the individual digestive organs, during the initial looping of the primitive gut tube, the left side assumes concave topologies where the right side becomes convex. Of interest, the concave surfaces of the gut tube correlate with expression of the LR gene, Pitx2, and ectopic Pitx2 mRNA induces ectopic concavities in a localized manner. A morphometric comparison of the prospective concave and convex surfaces of the gut tube reveals striking disparities in their rate of elongation but no significant differences in cell proliferation. These results provide insight into the nature of symmetry-breaking morphogenetic events during left-right asymmetric organ development. ?? 2003 Wiley-Liss, Inc.

  18. Asymmetric visual interactions across the boundary of awareness.

    PubMed

    Meital-Kfir, Noya; Bonneh, Yoram S; Sagi, Dov

    2016-08-01

    A salient visual object can disappear from conscious perception when surrounded by a moving texture, a phenomenon known as MIB, Motion-Induced Blindness (Bonneh, Cooperman, & Sagi, 2001). Here we tested the information available in the brain from such stimuli that do not access awareness by examining interactions across the boundary of awareness between stimuli that reach awareness and those that do not. Observers performed the MIB task in which a "Cue" was presented next to the "Target" after observers reported the perceptual disappearance of the target (Kawabe, Yamada, & Miura, 2007). Oriented Gabor patches were used as targets and cues; observers reported the target's reappearance. The results indicated an interaction between the target and the cue, depending on the orientation difference (∼30° bandwidth) and distance (∼1° range), indicating preserved properties of features in the absence of awareness. Object-based representation (binding) of unseen stimuli was tested by examining the interaction between a compound stimulus and its composing features. Here we used vertical and horizontal Gabor patches and their combinations (plaids) as targets and cues. Results indicated asymmetric relations between aware and unaware object representations; a plaid cue was not effective with a component target, but a plaid target efficiently reappeared by its component cues. This result suggests that the unseen, but not the seen plaid, is decomposed into its features. Plaid targets also reappeared with plaid cues, supporting binding without awareness. Our findings suggest preconscious representations of objects and their features, with conscious perception confined to object representations. PMID:27494546

  19. Social evolution in the shadow of asymmetrical relatedness

    PubMed Central

    Krupp, D. B.; Taylor, Peter D.

    2015-01-01

    The persistence of altruism and spite remains an enduring problem of social evolution. It is well known that selection for these actions depends on the structure of the population—that is, on actors' genetic relationships to recipients and to the ‘neighbourhood’ upon which the effects of their actions redound. Less appreciated, however, is that population structure can cause genetic asymmetries between partners whereby the relatedness (defined relative to the neighbourhood) of an individual i to a partner j will differ from the relatedness of j to i. Here, we introduce a widespread mechanism of kin recognition to a model of dispersal in subdivided populations. In so doing, we uncover three remarkable consequences of asymmetrical relatedness. First, altruism directed at phenotypically similar partners evolves more easily among migrant than native actors. Second, spite directed at dissimilar partners evolves more easily among native than migrant actors. Third, unlike migrants, natives can evolve to pay costs that far outstrip those they spitefully impose on others. We find that the frequency of natives relative to migrants amplifies the asymmetries between them. Taken together, our results reveal differentiated patterns of ‘phenocentrism’ that readily arise from asymmetries of relatedness. PMID:25925099

  20. Asymmetric dark matter models and the LHC diphoton excess

    NASA Astrophysics Data System (ADS)

    Frandsen, Mads T.; Shoemaker, Ian M.

    2016-05-01

    The existence of dark matter (DM) and the origin of the baryon asymmetry are persistent indications that the SM is incomplete. More recently, the ATLAS and CMS experiments have observed an excess of diphoton events with invariant mass of about 750 GeV. One interpretation of this excess is decays of a new spin-0 particle with a sizable diphoton partial width, e.g. induced by new heavy weakly charged particles. These are also key ingredients in models cogenerating asymmetric DM and baryons via sphaleron interactions and an initial particle asymmetry. We explore what consequences the new scalar may have for models of asymmetric DM that attempt to account for the similarity of the dark and visible matter abundances.

  1. Asymmetrical directional mutation pressure in the mitochondrial genome of mammals.

    PubMed

    Reyes, A; Gissi, C; Pesole, G; Saccone, C

    1998-08-01

    The base composition of 25 complete mammalian mitochondrial (mt) genomes has been analyzed taking into account all three codon positions (P1230 and fourfold degenerate sites (P4FD) of H-strand genes. In the nontranscribed L strand, G is the less represented base and A is the most represented one in all cases, while C and T differ among species. H-strand protein-coding genes show an asymmetric distribution of the four bases between the two strands. The asymmetry indexes AT and GC skews on P4FD are much higher than those on P123, suggesting the existence of asymmetrical directional mutation pressure. Relationships between the compositional features and transcription of replication processes have been investigated in order to find a possible mechanism that could explain the origin of this asymmetry. AT and GC skews, the base composition in fourfold degenerate sites, and the number of variable sites for each gene are significantly correlated with the duration of single-stranded state of the H-stranded genes during replication. We tested different replication-related hypotheses, such as the existence of biased dNTP pools, gamma DNA polymerase mispairing, and the asymmetric replication itself. Most of them failed to explain the observed results, hydrolytic deaminations being the only one in agreement with our data. Thus, we hypothesize that one of the crucial processes for the origin of asymmetric and biased base composition of mammalian mitochondrial genomes is the spontaneous deamination of C and A in the H strand during replication. PMID:9718723

  2. Baseline Testing of the Club Car Carryall With Asymmetric Ultracapacitors

    NASA Technical Reports Server (NTRS)

    Eichenberg, Dennis J.

    2003-01-01

    The NASA John H. Glenn Research Center initiated baseline testing of the Club Car Carryall with asymmetric ultracapacitors as a way to reduce pollution in industrial settings, reduce fossil fuel consumption, and reduce operating costs for transportation systems. The Club Car Carryall provides an inexpensive approach to advance the state of the art in electric vehicle technology in a practical application. The project transfers space technology to terrestrial use via non-traditional partners, and provides power system data valuable for future space applications. The work was done under the Hybrid Power Management (HPM) Program, which includes the Hybrid Electric Transit Bus (HETB). The Carryall is a state of the art, ground up, electric utility vehicle. A unique aspect of the project was the use of a state of the art, long life ultracapacitor energy storage system. Innovative features, such as regenerative braking through ultracapacitor energy storage, are planned. Regenerative braking recovers much of the kinetic energy of the vehicle during deceleration. The Carryall was tested with the standard lead acid battery energy storage system, as well as with an asymmetric ultracapacitor energy storage system. The report concludes that the Carryall provides excellent performance, and that the implementation of asymmetric ultracapacitors in the power system can provide significant performance improvements.

  3. Experimental investigation of the asymmetric body vortex wake

    NASA Technical Reports Server (NTRS)

    Oberkampf, W. L.; Shivananda, T. P.; Owen, F. K.

    1980-01-01

    An experimental investigation of the asymmetric body vortex wake of a circular cylinder in high subsonic flow is presented. Laser velocimeter, force and moment, and surface hot wire measurements were obtained for a freestream Mach number of 0.6 and Reynolds number (based on body diameter) of 0.62 x 10 to the 6th. Two component laser velocimeter measurements were made at three body cross-flow planes, x/d = 4, 8, and 12, and angles of attack of 25, 35, and 45 deg. Laser vapor screen photographs were also obtained at these body stations and angles of attack. Surface hot wire measurements were used to determine if any vortex switching occurred at various angles of attack of the body. The laser velocimeter measurements are related to the vapor screen photographs and side force measurements. These results show that more than one asymmetric body vortex wake configuration can exist for the same angle of attack and body roll angle.

  4. Underwater asymmetric acoustic transmission structure using the medium with gradient change of impedance

    NASA Astrophysics Data System (ADS)

    Bo, Hu; Jie, Shi; Sheng-Guo, Shi; Yu, Sun; Zhong-Rui, Zhu

    2016-02-01

    We propose an underwater asymmetric acoustic transmission structure comprised of two media each with a gradient change of acoustic impedance. By gradually increasing the acoustic impedances of the media, the propagating direction of the acoustic wave can be continuously bent, resulting in allowing the acoustic wave to pass through along the positive direction and blocking acoustic waves from the negative one. The main advantages of this structure are that the asymmetric transmission effect of this structure can be realized and enhanced more easily in water. We investigate both numerically and experimentally the asymmetric transmission effect. The experimental results show that a highly efficient asymmetric acoustic transmission can be yielded within a remarkable broadband frequency range, which agrees well with the numerical prediction. It is of potential practical significance for various underwater applications such as reducing vibration and noise. Project supported by the National Natural Science Foundation of China (Grant Nos. 11204049 and 11204050), the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China (Grant No. IRT1228), and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant Nos. 20122304120023 and 20122304120011).

  5. Effect of adiabatic square ribs on natural convection in an asymmetrically heated channel

    NASA Astrophysics Data System (ADS)

    Abidi-Saad, Aissa; Kadja, Mahfoud; Popa, Catalin; Polidori, Guillaume

    2016-06-01

    A 2-D numerical simulation is carried out to investigate the effect of two adiabatic square ribs on laminar flow and heat transfer in an asymmetrically heated channel. The two ribs are symmetrically located on each wall, exactly above the heating zone. The computational procedure is made by solving the unsteady bi-dimensional continuity, momentum and energy equations with the finite volume method. The investigations focused more specifically on the influence of ribs sizes on the flow structure and heat transfer enhancement. The results showed that the variation of ribs sizes significantly alters the heat transfer and fluid flow distribution along the channel, especially in the vicinity of protrusions. Also, the results show that streamlines, isotherms, and the number, sizes and formation of vortex structures inside the channel strongly depend on the size of protrusions. The changes in heat transfer parameters have also been presented.

  6. Effective Hamiltonian for a half-filled asymmetric ionic Hubbard chain with alternating on-site interaction

    NASA Astrophysics Data System (ADS)

    Grusha, I.; Menteshashvili, M.; Japaridze, G. I.

    2016-01-01

    We derive an effective spin Hamiltonian for the one-dimensional half-filled asymmetric ionic Hubbard model (IHM) with alternating on-site interaction in the limit of strong repulsion. It is shown that the effective Hamiltonian is that of a spin S = 1/2 anisotropic XXZ Heisenberg chain with alternating next-nearest-neighbor (NNN) and three-spin couplings in the presence of a uniform and a staggered magnetic field.

  7. Effects of curvature on asymmetric steady states in catalyst particles

    SciTech Connect

    Lucier, B J

    1981-02-01

    The effects of curvature on steady states of chemical catalytic reactions are investigated by studying the cases of the catalytic particle being a spherical or cylindrical shell. Existence and stability of solutions are studied. It is shown that the solutions converge to the solutions for the catalytic slab when the curvature goes to 0 in each case.

  8. Recovery of the Aharonov-Bohm oscillations in asymmetrical quantum rings

    NASA Astrophysics Data System (ADS)

    Voskoboynikov, O.

    2016-07-01

    We theoretically investigate suppression and recovery of the Aharonov-Bohm oscillations of the diamagnetic response of electrons (holes) confined in self-assembled IncGa1-cAs/GaAs semiconductor reflection asymmetrical quantum rings. Based on the mapping method and gauge-origin-independent definition for the magnetic vector potential we simulate the energies and wave functions of the electron (hole) under external magnetic and electric fields. We examine the transformation of the ground state wave function of the electron (hole) in reflection asymmetrical rings from localized in one of the potential valleys (dotlike shape of the wave function) to distributed over all volume of the ring (ringlike shape) under an appropriate lateral electric field. This transformation greatly recovers the electron (hole) diamagnetic coefficient and Aharonov-Bohm oscillations of the diamagnetic response of the ring. However, the recovering electric field for the first Aharonov-Bohm diamagnetic oscillation of the electron is a suppressing one for the hole (and vice versa). This can block the recovery of the optical Aharonow-Bohm effect in IncGa1-cAs/GaAs asymmetrically wobbled rings. However, the recovery of the Aharonov-Bohm oscillations for the independent electron (hole) by the external electric field remains interesting and feasible objective for the asymmetric rings.

  9. Polarization effect in (e, 2e) reaction process for Ar (3s) in coplanar asymmetric geometry

    NASA Astrophysics Data System (ADS)

    Zhou, Li-Xia; Wang, Dian-Sheng; Yan, You-Guo; Wang, Cai-Ling

    2014-11-01

    The (e, 2e) triple differential cross sections (TDCSs) of Ar (3s) are calculated by using distorted-wave Born approximation under coplanar asymmetric geometry. The incident electron energy is 113.5 eV, and the scattering electron angle θ1 is -15°. The ejected electron energy is set at 10 eV, 7.5 eV, 5 eV, and 2 eV, respectively. The polarization effects have been discussed and the polarization potential Vpol changing from a second-order to a fourth-order term has been analyzed. Our calculated TDCSs have been compared with reported experimental and theoretical results, and the calculated TDCSs of polarization potential up to the fourth order could give a good fit with experimental results in the binary region, but fail to predict the correct recoil-to-binary ratio in most cases.

  10. OBSERVATIONS OF THE CRAB NEBULA'S ASYMMETRICAL DEVELOPMENT

    SciTech Connect

    Loll, A. M.; Desch, S. J.; Scowen, P. A.; Foy, J. P.

    2013-03-10

    We present the first Hubble Space Telescope Wide Field Planetary Camera-2 imaging survey of the entire Crab Nebula, in the filters F502N ([O III] emission), F673N ([S II]), F631N ([O I]), and F547M (continuum). We use our mosaics to characterize the pulsar wind nebula (PWN) and its three-dimensional structure, the ionizational structure in the filaments forming at its periphery, the speed of the shock driven by the PWN into surrounding ejecta (by inferring the cooling rates behind the shock), and the morphology and ionizational structure of the Rayleigh-Taylor (R-T) fingers. We quantify a number of asymmetries between the northwest (NW) and southeast (SE) quadrants of the Crab Nebula. The lack of observed filaments in the NW, and our observations of the spatial extent of [O III] emission lead us to conclude that cooling rates are slower, and therefore the shock speeds are greater, in the NW quadrant of the nebula, compared with the SE. We conclude that R-T fingers are longer, more ionizationally stratified, and apparently more massive in the NW than in the SE, and the R-T instability appears more fully developed in the NW.

  11. The Asymmetric Wind in M82

    NASA Astrophysics Data System (ADS)

    Shopbell, P. L.; Bland-Hawthorn, J.

    1998-01-01

    We have obtained detailed Fabry-Perot imaging observations of the nearby galaxy M82 in order to understand the physical association between the high-velocity outflow and the starburst nucleus. The high spatial and kinematic resolution of our observations has allowed us to perform photometric analyses of Hα, [N II], and [O III] spectral lines at roughly 100,000 positions across the extent of the galaxy. The observed velocities of the emitting gas in M82 reveal a bipolar outflow of material, originating from the bright starburst regions in the galaxy's inner disk but misaligned with respect to the galaxy spin axis. The deprojected outflow velocity indicated by the optical filaments increases with radius from 525 to 655 km s-1. All three spectral lines show double components in the centers of the outflowing lobes, with the Hα line split by ~300 km s-1 over a region almost 1 kpc in size. The filamentary lobes lie along an axis tilted by 15° with respect to the spin axis, a finding confirmed by the regions of line splitting and by the ionization pattern over the outflow. The filaments are not simple surfaces of revolution, nor is the emission distributed evenly over the surfaces. We model these lobes as a composite of cylindrical and conical structures, collimated in the inner ~500 pc but expanding at a larger opening angle of ~25° beyond that radius. We compare our kinematic model with simulations of starburst-driven winds in which disk material surrounding the source is entrained by the wind. There is some evidence for rotation of the wind filaments about the outflow axis in support of entrainment, and we find strong similarities between the observed and predicted structures. The data reveal a remarkably low [N II]/Hα ratio in the region of the outflow, indicating that photoionization by the nuclear starburst may play a significant role in the excitation of the optical filament gas, particularly near the nucleus. An increase in the [O III]/Hα ratio along the

  12. How the IMF By induces a By component in the closed magnetosphere and how it leads to asymmetric currents and convection patterns in the two hemispheres

    NASA Astrophysics Data System (ADS)

    Tenfjord, P.; Østgaard, N.; Snekvik, K.; Laundal, K. M.; Reistad, J. P.; Haaland, S.; Milan, S. E.

    2015-11-01

    We used the Lyon-Fedder-Mobarry global magnetohydrodynamics model to study the effects of the interplanetary magnetic field (IMF) By component on the coupling between the solar wind and magnetosphere-ionosphere system. When the IMF reconnects with the terrestrial magnetic field with IMF By≠0, flux transport is asymmetrically distributed between the two hemispheres. We describe how By is induced in the closed magnetosphere on both the dayside and nightside and present the governing equations. The magnetosphere imposes asymmetric forces on the ionosphere, and the effects on the ionospheric flow are characterized by distorted convection cell patterns, often referred to as "banana" and "orange" cell patterns. The flux asymmetrically added to the lobes results in a nonuniform induced By in the closed magnetosphere. By including the dynamics of the system, we introduce a mechanism that predicts asymmetric Birkeland currents at conjugate foot points. Asymmetric Birkeland currents are created as a consequence of y directed tension contained in the return flow. Associated with these currents, we expect fast localized ionospheric azimuthal flows present in one hemisphere but not necessarily in the other. We also present current density measurements from Active Magnetosphere and Planetary Electrodynamics Response Experiment that are consistent with this picture. We argue that the induced By produces asymmetrical Birkeland currents as a consequence of asymmetric stress balance between the hemispheres. Such an asymmetry will also lead to asymmetrical foot points and asymmetries in the azimuthal flow in the ionosphere. These phenomena should therefore be treated in a unified way.

  13. Photovoltaic Effect and Evidence of Carrier Multiplication in Graphene Vertical Homojunctions with Asymmetrical Metal Contacts.

    PubMed

    Chen, Jing-Jing; Wang, Qinsheng; Meng, Jie; Ke, Xiaoxing; Van Tendeloo, Gustaaf; Bie, Ya-Qing; Liu, Junku; Liu, Kaihui; Liao, Zhi-Min; Sun, Dong; Yu, Dapeng

    2015-09-22

    Graphene exhibits exciting potentials for high-speed wideband photodetection and high quantum efficiency solar energy harvest because of its broad spectral absorption, fast photoelectric response, and potential carrier multiplication. Although photocurrent can be generated near a metal-graphene interface in lateral devices, the photoactive area is usually limited to a tiny one-dimensional line-like interface region. Here, we report photoelectric devices based on vertical graphene two-dimensional homojunction, which is fabricated via vertically stacking four graphene monolayers with asymmetric metal contacts. The devices show excellent photovoltaic output with excitation wavelength ranging from visible light to mid-infrared. The wavelength dependence of the internal quantum efficiency gives direct evidence of the carrier multiplication effect in graphene. The simple fabrication process, easy scale-up, large photoresponsive active area, and broadband response of the vertical graphene device are very promising for practical applications in optoelectronics and photovoltaics. PMID:26279456

  14. Proportion congruency and practice: A contingency learning account of asymmetric list shifting effects.

    PubMed

    Schmidt, James R

    2016-09-01

    Performance is impaired when a distracting stimulus is incongruent with the target stimulus (e.g., "green" printed in red). This congruency effect is decreased when the proportion of incongruent trials is increased, termed the proportion congruent effect. This effect is typically interpreted in terms of the adaptation of attention in response to conflict. In contrast, the contingency account argues that the effect is driven by the learning of predictive relationships between words and responses. In a recent report, Abrahamse, Duthoo, Notebaert, and Risko (2013) demonstrated larger changes in the magnitude of the proportion congruent effect when switching from a mostly congruent list to a mostly incongruent list, relative to the reverse order. They argued that this asymmetric list shifting effect fits only with the conflict adaptation perspective. However, the current paper presents reanalyses of this data and an adaptation of the Parallel Episodic Processing model that together demonstrate how the contingency account can explain these findings equally well when considering the generally accepted notion that performance improves with practice. The contingency account may still be the most parsimonious view. (PsycINFO Database Record PMID:27585071

  15. Asymmetrical intersection between the middle cerebral artery and rhinal vein suggests asymmetrical gustatory cortex location in rodent hemispheres.

    PubMed

    Kida, Ikuhiro; Enmi, Jun-Ichiro; Iida, Hidehiro; Yoshioka, Yoshichika

    2015-03-01

    The rodent gustatory cortex is located in the anterior part of the insular cortex, which is near the dorsal part of the rhinal vein (RHV) and the intersection of the anterior and posterior regions of the middle cerebral artery (MCA). Thus, the intersection between the RHV and MCA is used as a landmark for the rodent gustatory cortex. In our previous study, we employed functional magnetic resonance imaging (MRI) to demonstrate that tastants evoked bilateral responses in the rodent insular cortices, but that these representations were asymmetrical between the hemispheres. In the present study, to clarify the observed asymmetrical responses, we performed magnetic resonance angiography in a 7.0-Tesla MRI scanner to determine the anatomical position of the rodent gustatory cortex, which was identified using the intersection of the MCA and RHV. We successfully observed the intersection while administering carbogen as an inhaled gas and found that the intersection in the left hemisphere is more anterior compared to that in the right hemisphere. Taken together with the previous functional MRI results, this result indicates that the gustatory representation in relation to the intersection may be identically conserved in the insular cortex of both hemispheres; therefore, the rodent gustatory cortex may be asymmetrically located between the left and right hemispheres. The result also suggests that this landmark location needs to be verified when investigating gustatory representations and responses. PMID:25578950

  16. The plasmoid instability during asymmetric inflow magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Murphy, Nicholas A.; Young, Aleida K.; Shen, Chengcai; Lin, Jun; Ni, Lei

    2013-06-01

    Theoretical studies of the plasmoid instability generally assume that the reconnecting magnetic fields are symmetric. We relax this assumption by performing two-dimensional resistive magnetohydrodynamic simulations of the plasmoid instability during asymmetric inflow magnetic reconnection. Magnetic asymmetry modifies the onset, scaling, and dynamics of this instability. Magnetic islands develop preferentially into the weak magnetic field upstream region. Outflow jets from individual X-points impact plasmoids obliquely rather than directly as in the symmetric case. Consequently, deposition of momentum by the outflow jets into the plasmoids is less efficient, the plasmoids develop net vorticity, and shear flow slows down secondary merging between islands. Secondary merging events have asymmetry along both the inflow and outflow directions. Downstream plasma is more turbulent in cases with magnetic asymmetry because islands are able to roll around each other after exiting the current sheet. As in the symmetric case, plasmoid formation facilitates faster reconnection for at least small and moderate magnetic asymmetries. However, when the upstream magnetic field strengths differ by a factor of 4, the reconnection rate plateaus at a lower value than expected from scaling the symmetric results. We perform a parameter study to investigate the onset of the plasmoid instability as a function of magnetic asymmetry and domain size. There exist domain sizes for which symmetric simulations are stable but asymmetric simulations are unstable, suggesting that moderate magnetic asymmetry is somewhat destabilizing. We discuss the implications for plasmoid and flux rope formation in solar eruptions, laboratory reconnection experiments, and space plasmas. The differences between symmetric and asymmetric simulations provide some hints regarding the nature of the three-dimensional plasmoid instability.

  17. The plasmoid instability during asymmetric inflow magnetic reconnection

    SciTech Connect

    Murphy, Nicholas A.; Young, Aleida K.; Shen, Chengcai; Lin, Jun; Ni, Lei

    2013-06-15

    Theoretical studies of the plasmoid instability generally assume that the reconnecting magnetic fields are symmetric. We relax this assumption by performing two-dimensional resistive magnetohydrodynamic simulations of the plasmoid instability during asymmetric inflow magnetic reconnection. Magnetic asymmetry modifies the onset, scaling, and dynamics of this instability. Magnetic islands develop preferentially into the weak magnetic field upstream region. Outflow jets from individual X-points impact plasmoids obliquely rather than directly as in the symmetric case. Consequently, deposition of momentum by the outflow jets into the plasmoids is less efficient, the plasmoids develop net vorticity, and shear flow slows down secondary merging between islands. Secondary merging events have asymmetry along both the inflow and outflow directions. Downstream plasma is more turbulent in cases with magnetic asymmetry because islands are able to roll around each other after exiting the current sheet. As in the symmetric case, plasmoid formation facilitates faster reconnection for at least small and moderate magnetic asymmetries. However, when the upstream magnetic field strengths differ by a factor of 4, the reconnection rate plateaus at a lower value than expected from scaling the symmetric results. We perform a parameter study to investigate the onset of the plasmoid instability as a function of magnetic asymmetry and domain size. There exist domain sizes for which symmetric simulations are stable but asymmetric simulations are unstable, suggesting that moderate magnetic asymmetry is somewhat destabilizing. We discuss the implications for plasmoid and flux rope formation in solar eruptions, laboratory reconnection experiments, and space plasmas. The differences between symmetric and asymmetric simulations provide some hints regarding the nature of the three-dimensional plasmoid instability.

  18. The deal with diel: Temperature fluctuations, asymmetrical warming, and ubiquitous metals contaminants.

    PubMed

    Hallman, Tyler A; Brooks, Marjorie L

    2015-11-01

    Climate projections over the next century include disproportionately warmer nighttime temperatures ("asymmetrical warming"). Cool nighttime temperatures lower metabolic rates of aquatic ectotherms. In contaminated waters, areas with cool nights may provide thermal refugia from high rates of daytime contaminant uptake. We exposed Cope's gray tree frogs (Hyla chrysoscelis), southern leopard frogs (Lithobates sphenocephalus), and spotted salamanders (Ambystoma maculatum) to five concentrations of a mixture of cadmium, copper, and lead under three to four temperature regimes, representing asymmetrical warming. At concentrations with intermediate toxicosis at test termination (96 h), temperature effects on acute toxicity or escape distance were evident in all study species. Asymmetrical warming (day:night, 22:20 °C; 22:22 °C) doubled or tripled mortality relative to overall cooler temperatures (20:20 °C) or cool nights (22:18 °C). Escape distances were 40-70% shorter under asymmetrical warming. Results suggest potentially grave ecological impacts from unexpected toxicosis under climate change. PMID:26142755

  19. Aneutronic fusion on the base of asymmetrical centrifugal trap

    NASA Astrophysics Data System (ADS)

    Volosov, V. I.

    2006-08-01

    A physical design of a device that can be a base for a direct-conversion nuclear electric power station is considered. The project considers the aneutronic reaction P-11B in the asymmetric centrifugal trap. Kinetic energy of nuclear particles (alpha particles) is converted into electrical energy inside this device; no thermal cycle is used. Heating and recuperation of energy of protons and boron ions take place in the plasma space. The presented scheme differs significantly from the conventional thermonuclear fusion. 'Fast' protons, which are the main energy component of plasma, have an almost monoenergetic spectrum. This makes it possible to realize the 'resonance' fusion.

  20. Asymmetric Organocatalysis at the Service of Medicinal Chemistry

    PubMed Central

    2014-01-01

    The application of the most representative and up-to-date examples of homogeneous asymmetric organocatalysis to the synthesis of molecules of interest in medicinal chemistry is reported. The use of different types of organocatalysts operative via noncovalent and covalent interactions is critically reviewed and the possibility of running some of these reactions on large or industrial scale is described. A comparison between the organo- and metal-catalysed methodologies is offered in several cases, thus highlighting the merits and drawbacks of these two complementary approaches to the obtainment of very popular on market drugs or of related key scaffolds. PMID:24971178

  1. The role of biocatalysis in the asymmetric synthesis of alkaloids

    PubMed Central

    2013-01-01

    Alkaloids are not only one of the most intensively studied classes of natural products, their wide spectrum of pharmacological activities also makes them indispensable drug ingredients in both traditional and modern medicine. Among the methods for their production, biotechnological approaches are gaining importance, and biocatalysis has emerged as an essential tool in this context. A number of chemo-enzymatic strategies for alkaloid synthesis have been developed over the years, in which the biotransformations nowadays take an increasingly ‘central’ role. This review summarises different applications of biocatalysis in the asymmetric synthesis of alkaloids and discusses how recent developments and novel enzymes render innovative and efficient chemo-enzymatic production routes possible. PMID:25580241

  2. Antibacterial phototoxic effects of synthetic asymmetric and glycosylated curcuminoids in aqueous formulations: studies on curcumin and curcuminoids. LIV.

    PubMed

    Tovsen, Marianne Lilletvedt; Bruzell, Ellen; Ferrari, Erika; Saladini, Monica; Gaware, Vivek S; Másson, Már; Kristensen, Solveig; Tønnesen, Hanne Hjorth

    2014-11-01

    The aim of this study was to evaluate the in vitro phototoxic potential of synthetic asymmetric and glycosylated curcuminoids on planktonic model bacteria by counting the colony forming units. The Gram-positive Enterococcus faecalis and the Gram-negative Escherichia coli were exposed to aqueous solutions of the curcuminoids (⩽2.5 μM) in the presence or absence of selected pharmaceutical excipients (Pluronic F127, PEG 400 and HPγCD) in combination with a low irradiation dose (5 J/cm(2); λmax: 450 nm) of constant irradiance and time. All the asymmetric curcuminoids, but only one of the glycosylated curcuminoids demonstrated substantial phototoxic effect on E.faecalis (⩾4.7 log reduction). Only two of the asymmetric curcuminoids showed a moderate to low phototoxic effect on the more persistent E.coli. This study emphasized that aromatic hydroxyl substituents in the para-position are important to maintain the phototoxic potential of curcuminoids independent of molecular symmetry. Glycosylation of the aromatic substituents resulted in a substantial loss in phototoxicity towards planktonic bacteria, an apparent change in the non-radiative S₁-decay process and a weaker interaction with Pluronic F127 compared to the non-glycosylated curcuminoids. The selected excipients Pluronic F127, PEG 400 and HPγCD strongly influenced the phototoxic potential of the unsymmetrical, non-glycosylated compounds. PMID:25129700

  3. Influence of the dissipation mechanism on collisionless magnetic reconnection in symmetric and asymmetric current layers

    SciTech Connect

    Aunai, Nicolas; Hesse, Michael; Black, Carrie; Evans, Rebekah; Kuznetsova, Maria

    2013-04-15

    Numerical studies implementing different versions of the collisionless Ohm's law have shown a reconnection rate insensitive to the nature of the non-ideal mechanism occurring at the X line, as soon as the Hall effect is operating. Consequently, the dissipation mechanism occurring in the vicinity of the reconnection site in collisionless systems is usually thought not to have a dynamical role beyond the violation of the frozen-in condition. The interpretation of recent studies has, however, led to the opposite conclusion that the electron scale dissipative processes play an important dynamical role in preventing an elongation of the electron layer from throttling the reconnection rate. This work re-visits this topic with a new approach. Instead of focusing on the extensively studied symmetric configuration, we aim to investigate whether the macroscopic properties of collisionless reconnection are affected by the dissipation physics in asymmetric configurations, for which the effect of the Hall physics is substantially modified. Because it includes all the physical scales a priori important for collisionless reconnection (Hall and ion kinetic physics) and also because it allows one to change the nature of the non-ideal electron scale physics, we use a (two dimensional) hybrid model. The effects of numerical, resistive, and hyper-resistive dissipation are studied. In a first part, we perform simulations of symmetric reconnection with different non-ideal electron physics. We show that the model captures the already known properties of collisionless reconnection. In a second part, we focus on an asymmetric configuration where the magnetic field strength and the density are both asymmetric. Our results show that contrary to symmetric reconnection, the asymmetric model evolution strongly depends on the nature of the mechanism which breaks the field line connectivity. The dissipation occurring at the X line plays an important role in preventing the electron current layer

  4. Development of asymmetric inhibition underlying direction selectivity in the retina

    PubMed Central

    Wei, Wei; Hamby, Aaron M.; Zhou, Kaili; Feller, Marla B.

    2014-01-01

    Establishing precise synaptic connections is crucial to the development of functional neural circuits. The direction-selective circuit in the retina relies upon highly selective wiring of inhibitory inputs from starburst amacrine cells1 (SACs) onto four subtypes of on–off direction-selective ganglion cell (DSGC), each preferring motion in one of four cardinal directions2. It has been reported in rabbit that the SACs on the ‘null’ sides of DSGCs form functional GABA (γ-aminobutyric acid)-mediated synapses, whereas those on the preferred sides do not3. However, it is not known how the asymmetric wiring between SACs and DSGCs is established during development. Here we report that in transgenic mice with cell-type-specific labelling, the synaptic connections from SACs to DSGCs were of equal strength during the first postnatal week, regardless of whether the SAC was located on the preferred or null side of the DSGC. However, by the end of the second postnatal week, the strength of the synapses made from SACs on the null side of a DSGC significantly increased whereas those made from SACs located on the preferred side remained constant. Blocking retinal activity by intraocular injections of muscimol or gabazine during this period did not alter the development of direction selectivity. Hence, the asymmetric inhibition between the SACs and DSGCs is achieved by a developmental program that specifically strengthens the GABA-mediated inputs from SACs located on the null side, in a manner not dependent on neural activity. PMID:21131947

  5. The Asymmetrical Effects of Divided Attention on Encoding and Retrieval Processes: A Different View Based on an Interference with the Episodic Register

    PubMed Central

    Guez, Jonathan; Naveh-Benjamin, Moshe

    2013-01-01

    In this study, we evaluate the conceptualization of encoding and retrieval processes established in previous studies that used a divided attention (DA) paradigm. These studies indicated that there were considerable detrimental effects of DA at encoding on later memory performance, but only minimal effects, if any, on divided attention at retrieval. We suggest that this asymmetry in the effects of DA on memory can be due, at least partially, to a confound between the memory phase (encoding and retrieval) and the memory requirements of the task (memory “for” encoded information versus memory “at” test). To control for this confound, we tested memory for encoded information and for retrieved information by introducing a second test that assessed memory for the retrieved information from the first test. We report the results of four experiments that use measures of memory performance, retrieval latency, and performance on the concurrent task, all of which consistently show that DA at retrieval strongly disrupts later memory for the retrieved episode, similarly to the effects of DA at encoding. We suggest that these symmetrical disruptive effects of DA at encoding and retrieval on later retrieval reflect a disruption of an episodic buffer (EB) or episodic register component (ER), rather than a failure of encoding or retrieval operations per se. PMID:24040249

  6. Analytical study of the origin and behavior of asymmetric vortices

    NASA Technical Reports Server (NTRS)

    Tobak, Murray; Degani, David; Zilliac, Gregory G.

    1990-01-01

    An hypothesis advanced originally to explain computational observations is supported by theoretical considerations: The asymmetric mean flow observed on bodies of revolution at moderate to high angles of attack is the result of a convective instability of an originally symmetric flow to a time-invariant space-fixed disturbance. Additionally, the time-dependent fluctuations characteristic of the flow at higher angles of attack (up to 90 deg) are the result of an absolute instability of an originally steady flow to a small temporal disturbance of finite duration. Within a common domain, the instability mechanisms may coexist. The experimentally confirmed existence of bistable states, wherein the side-force variation with nose roll angle approaches a square-wave distribution, is attributed to the dominant influence of a pair of trailing vortices from the ogival forebody. Their existence is made possible by the appearance of foci of separation in the skin-friction line pattern beyond a critical angle of attack. The extreme sensitivity of the asymmetric flow orientation to nose geometry, demonstrated experimentally, is attributed to the presence of an indeterminate phase in the family of possible solutions for the three-dimensional wave system.

  7. Optimization of backward giant circle technique on the asymmetric bars.

    PubMed

    Hiley, Michael J; Yeadon, Maurice R

    2007-11-01

    The release window for a given dismount from the asymmetric bars is the period of time within which release results in a successful dismount. Larger release windows are likely to be associated with more consistent performance because they allow a greater margin for error in timing the release. A computer simulation model was used to investigate optimum technique for maximizing release windows in asymmetric bars dismounts. The model comprised four rigid segments with the elastic properties of the gymnast and bar modeled using damped linear springs. Model parameters were optimized to obtain a close match between simulated and actual performances of three gymnasts in terms of rotation angle (1.5 degrees ), bar displacement (0.014 m), and release velocities (<1%). Three optimizations to maximize the release window were carried out for each gymnast involving no perturbations, 10-ms perturbations, and 20-ms perturbations in the timing of the shoulder and hip joint movements preceding release. It was found that the optimizations robust to 20-ms perturbations produced release windows similar to those of the actual performances whereas the windows for the unperturbed optimizations were up to twice as large. It is concluded that robustness considerations must be included in optimization studies in order to obtain realistic results and that elite performances are likely to be robust to timing perturbations of the order of 20 ms. PMID:18089928

  8. Orientation of the X-line in asymmetric magnetic reconnection

    NASA Astrophysics Data System (ADS)

    Aunai, N.; Hesse, M.; Lavraud, B.; Dargent, J.; Smets, R.

    2016-08-01

    > Magnetic reconnection can occur in current sheets separating magnetic fields sheared by any angle and of arbitrarily different amplitudes. In such asymmetric and non-coplanar systems, it is not yet understood what the orientation of the X-line will be. Studying how this orientation is determined locally by the reconnection process is important to understand systems such as the Earth magnetopause, where reconnection occurs in regions with large differences in upstream plasma and field properties. This study aims at determining what the local X-line orientation is for different upstream magnetic shear angles in an asymmetric set-up relevant to the Earth's magnetopause. We use two-dimensional hybrid simulations and vary the simulation plane orientation with regard to the fixed magnetic field profile and search for the plane maximizing the reconnection rate. We find that the plane defined by the bisector of upstream fields maximizes the reconnection rate and this appears not to depend on the magnetic shear angle, domain size or upstream plasma and asymmetries.

  9. Asymmetric dark matter

    SciTech Connect

    Kumar, Jason

    2014-06-24

    We review the theoretical framework underlying models of asymmetric dark matter, describe astrophysical constraints which arise from observations of neutron stars, and discuss the prospects for detecting asymmetric dark matter.

  10. Asymmetric dynamics and critical behavior in the Bak-Sneppen model

    NASA Astrophysics Data System (ADS)

    Garcia, Guilherme J. M.; Dickman, Ronald

    2004-11-01

    We investigate, using mean-field theory and simulation, the effect of asymmetry on the critical behavior and probability density of Bak-Sneppen models. Two kinds of anisotropy are investigated: (i) different numbers of sites to the left and right of the central (minimum) site are updated and (ii) sites to the left and right of the central site are renewed in different ways. Of particular interest is the crossover from symmetric to asymmetric scaling for weakly asymmetric dynamics, and the collapse of data with different numbers of updated sites but the same degree of asymmetry. All non-symmetric rules studied fall, independent of the degree of asymmetry, in the same universality class. Conversely, symmetric variants reproduce the exponents of the original model. Our results confirm the existence of two symmetry-based universality classes for extremal dynamics.

  11. Linearisation of asymmetrical Doherty amplifier by the even-order non-linear signals

    NASA Astrophysics Data System (ADS)

    Maleš-Ilić, Nataša; Atanasković, Aleksandar; Blau, Kurt; Hein, Matthias

    2016-08-01

    This paper considers the linearisation of an asymmetrical two-way Doherty amplifier by the method that uses the second harmonics and fourth-order non-linear signals for linearisation. These even-order signals for linearisation are extracted at the output of the peaking amplifier, adjusted in amplitude and phase and injected at the input and output of the carrier amplifier transistor in the Doherty configuration. The effect of linearisation has been experimentally confirmed on a fabricated asymmetrical Doherty amplifier with the additional circuit for linearisation. The suppression of the third-order intermodulation products has been carried out for two-tone test, 64QAM and WCDMA digitally modulated signals in a range of signal power.

  12. Influence of an asymmetric ring on the modeling of an orthogonally stiffened cylindrical shell

    NASA Technical Reports Server (NTRS)

    Rastogi, Naveen; Johnson, Eric R.

    1994-01-01

    Structural models are examined for the influence of a ring with an asymmetrical cross section on the linear elastic response of an orthogonally stiffened cylindrical shell subjected to internal pressure. The first structural model employs classical theory for the shell and stiffeners. The second model employs transverse shear deformation theories for the shell and stringer and classical theory for the ring. Closed-end pressure vessel effects are included. Interacting line load intensities are computed in the stiffener-to-skin joints for an example problem having the dimensions of the fuselage of a large transport aircraft. Classical structural theory is found to exaggerate the asymmetric response compared to the transverse shear deformation theory.

  13. 0114 + 074 - A very asymmetric galaxy in the field of an intermediate-redshift QSO

    SciTech Connect

    Akujor, C.E. Max-Planck-Institut fuer Radioastronomie, Bonn )

    1989-10-01

    New radio-continuum observations of 0114 + 074 (4C 07.4) are presented. It is shown that this radio source consists of two distinct objects: a point source identified with an 18.0 mag QSO and a highly asymmetric 18.5 mag galaxy. The patently asymmetric structure of the galaxy is most plausibly due to intrinsically asymmetric energy funding of the lobes by the central machine or nucleus, rather than external influences. 41 refs.

  14. Experimental and theoretical study of the weak and asymmetrical thermal lens effect of Nd:YLF crystal for σ and π polarizations

    NASA Astrophysics Data System (ADS)

    Zhang, Zilong; Liu, Qiang; Nie, Mingming; Ji, Encai; Gong, Mali

    2015-09-01

    The thermal lens effect of Nd:YLF crystal for different polarized beams is experimentally and theoretically studied in this paper. In the experiment, the different thermal lens effects of Nd:YLF crystal along a and c axes for π- and σ-polarized probe beams are observed, and the values of the focal lengths are measured. The theoretical analysis is made to explain the extremely weak thermal lens effect along the c axis, as well as that for the σ-polarized beam. And it is corroborated that the complementation among the thermo-optical coefficient, the thermal end bulging and the photoelastic effects contributes to the weak and asymmetry thermal lens effect of Nd:YLF crystal.

  15. Overcoming asymmetric goals in teams: the interactive roles of team learning orientation and team identification.

    PubMed

    Pearsall, Matthew J; Venkataramani, Vijaya

    2015-05-01

    Although members of teams share a common, ultimate objective, they often have asymmetric or conflicting individual goals that shape the way they contribute to, and pursue, the shared goal of the team. Compounding this problem, they are frequently unaware of the nature of these goal asymmetries or even the fact that such differences exist. Drawing on, and integrating, social interdependence and representational gaps theories, we identify 2 emergent states that combine interactively to enable teams to overcome asymmetric goals: team identification and team learning orientation. Using data from long-term, real-life teams that engaged in a computer simulation designed to create both asymmetric goals and representational gaps about those goals, we found that teams were most effective when they had a high learning orientation coupled with high team identification and that this effect was mediated by teams' ability to form more accurate team goal mental models and engage in effective planning processes. Implications for theory and practice are discussed. PMID:25384202

  16. Visual attention modulates the asymmetric influence of each cerebral hemisphere on spatial perception

    PubMed Central

    Wang, Meijian; Wang, Xiuhai; Xue, Lingyan; Huang, Dan; Chen, Yao

    2016-01-01

    Although the allocation of brain functions across the two cerebral hemispheres has aroused public interest over the past century, asymmetric interhemispheric cooperation under attentional modulation has been scarcely investigated. An example of interhemispheric cooperation is visual spatial perception. During this process, visual information from each hemisphere is integrated because each half of the visual field predominantly projects to the contralateral visual cortex. Both egocentric and allocentric coordinates can be employed for visual spatial representation, but they activate different areas in primate cerebral hemispheres. Recent studies have determined that egocentric representation affects the reaction time of allocentric perception; furthermore, this influence is asymmetric between the two visual hemifields. The egocentric-allocentric incompatibility effect and its asymmetry between the two hemispheres can produce this phenomenon. Using an allocentric position judgment task, we found that this incompatibility effect was reduced, and its asymmetry was eliminated on an attentional task rather than a neutral task. Visual attention might activate cortical areas that process conflicting information, such as the anterior cingulate cortex, and balance the asymmetry between the two hemispheres. Attention may enhance and balance this interhemispheric cooperation because this imbalance may also be caused by the asymmetric cooperation of each hemisphere in spatial perception. PMID:26758349

  17. Visual attention modulates the asymmetric influence of each cerebral hemisphere on spatial perception.

    PubMed

    Wang, Meijian; Wang, Xiuhai; Xue, Lingyan; Huang, Dan; Chen, Yao

    2016-01-01

    Although the allocation of brain functions across the two cerebral hemispheres has aroused public interest over the past century, asymmetric interhemispheric cooperation under attentional modulation has been scarcely investigated. An example of interhemispheric cooperation is visual spatial perception. During this process, visual information from each hemisphere is integrated because each half of the visual field predominantly projects to the contralateral visual cortex. Both egocentric and allocentric coordinates can be employed for visual spatial representation, but they activate different areas in primate cerebral hemispheres. Recent studies have determined that egocentric representation affects the reaction time of allocentric perception; furthermore, this influence is asymmetric between the two visual hemifields. The egocentric-allocentric incompatibility effect and its asymmetry between the two hemispheres can produce this phenomenon. Using an allocentric position judgment task, we found that this incompatibility effect was reduced, and its asymmetry was eliminated on an attentional task rather than a neutral task. Visual attention might activate cortical areas that process conflicting information, such as the anterior cingulate cortex, and balance the asymmetry between the two hemispheres. Attention may enhance and balance this interhemispheric cooperation because this imbalance may also be caused by the asymmetric cooperation of each hemisphere in spatial perception. PMID:26758349

  18. Projection of two-dimensional diffusion in narrow asymmetric channels onto the longitudinal direction

    SciTech Connect

    Pineda, Inti; Dagdug, Leonardo

    2014-01-14

    Diffusive transport of particles is a ubiquitous feature of physical, chemical and biological systems. Typical structures like pores, tubes or fibers, are quasi one-dimensional, such that we need to solve 2+1 or 3+1 dimensional differential equations to describe correctly transport along them. The so-called Fick-Jacobs approach dramatically simplifies the problem if one assumes that a solute distribution in any cross-section of the channel is uniform at equilibrium. That study focuses on the mapping of the diffusion equation in a two-dimensional narrow asymmetric channel of varying cross section onto the longitudinal coordinate. We present a generalization to the case of an asymmetric channel using the projection method introduced earlier by Kalinay and Percus. We derive an expansion of the effective diffusion coefficient, which represents corrections to the Fick-Jacobs equation and contains the well-known previous results as special cases. Finally, we study numerically some specific two-dimensional asymmetric channel configurations to test and show the broader applicability of this effective diffusion coefficient formula.

  19. Asymmetric variations of the coronal green line intensity

    NASA Astrophysics Data System (ADS)

    Tritakis, V. P.; Petropoulos, B.; Mavromichalaki, H.

    1988-09-01

    The analysis of the daily measurements of the coronal green line intensity, which have been extensively tested for homogeneity and freedom of trends observed at the Pic-du-Midi observatory during the period 1944 - 1974, has revealed some characteristic asymmetric variations. The NW solar-quarter appears to be the most active of all in the 22-yr cycle 1949 - 1971, while in the periods 1944 - 1948 and 1972 - 1974 the SW quarter is the most active. The green line intensity distribution shows that the maximum values of the asymmetries occur in heliocentric sectors ±10° - 20° far from the solar equator on both sides of the central meridian. Physical mechanisms like different starting time of an 11-yr solar cycle in the two solar hemispheres, the motion of the Sun towards the Apex, and short-lived "active" solar longitudes formed by temporal clustering of solar active centers, have been discussed.

  20. From generalized directed animals to the asymmetric simple exclusion process

    NASA Astrophysics Data System (ADS)

    Haug, N.; Nechaev, S.; Tamm, M.

    2014-10-01

    Using the generalized normally ordered form of words in a locally-free group of n generators, we show that in the limit n → ∞, the partition function of weighted directed lattice animals on a semi-infinite strip coincides with the partition function of stationary configurations of the asymmetric simple exclusion process (ASEP) with arbitrary entry/escape rates through open boundaries. We relate the features of the ASEP in the different regimes of the phase diagram to the geometric features of the associated generalized directed animals by showing the results of numerical simulations. In particular, we show how the presence of shocks at the first order transition line translates into the directed animal picture. Using the evolution equation for generalized, weighted Lukasiewicz paths, we also provide a straightforward calculation of the known ASEP generating function.

  1. Effects of Multiple Nozzles on Asymmetric Ejector Performance

    NASA Technical Reports Server (NTRS)

    Lineberry, D.; Landrum, B.

    2005-01-01

    This paper presents a comparison of a single nozzle and a dual nozzle strut based ejector. The results are focused on the fluid properties in the ejector duct. The research focused on choking mechanisms, mass flow entrainment, and mixing duct pressure distributions. The two ejectors were tests at equivalent primary mass flow rates. This corresponds to chamber pressures ranging from 100 psi to 900 psi in the single nozzle strut and 50 psi to 450 psi in the dual nozzle strut. Secondary flow was drawn from the lab at atmospheric pressure, and was not controlled. The secondary flow was found to choke at a value of 2.3 lb/s for a primary mass flow rate at approximately 2.1 lb/s for both ejectors. This choke was believed to be a mass addition choke rather than a traditional aerodynamic choke. The mixing duct pressure distribution exhibited two distinct trends at "low pressure" trend and at "high pressure" trend. For the low pressure trend, the mixing length for the ejectors remained fixed around 20 inches, regardless of the chamber pressure. For the higher pressure trend, the mixing length was considerably longer and increased with increasing chamber pressure. At high chamber pressures (high mass flow rates), a supersonic core flow was present at the exit of the duct. For these cases, the two streams did not have time to mix by the end of the duct.

  2. The particle distributions of asymmetric kinetic electrostatic structures

    SciTech Connect

    Nocera, L.; Palumbo, L. J.

    2011-03-15

    We give the energy distributions of electrons and ions supporting a steady state electrostatic structure in a collisionless plasma. The electric potential of the structure is skew asymmetrically distributed in space. We show that the jump discontinuous, logarithmically singular electron and ion distributions may be reduced to elliptic integrals. We give the coefficients of the logarithmic terms and the jumps at the discontinuities and we show that they are reciprocally proportional. We calculate bounds for the potential skew asymmetry and show that these bounds are regulated by the boundary conditions of the particle distributions. Despite singularities, our treatment reproduces a smooth space distribution of the potential amplitude and electron and ion distributions that are smooth at one of the boundaries of the electrostatic structure.

  3. Finite-Time Fluctuations for the Totally Asymmetric Exclusion Process

    NASA Astrophysics Data System (ADS)

    Prolhac, Sylvain

    2016-03-01

    The one-dimensional totally asymmetric simple exclusion process, a Markov process describing classical hard-core particles hopping in the same direction, is considered on a periodic lattice of L sites. The relaxation to the nonequilibrium steady state, which occurs on the time scale t ˜L3 /2 for large L , is studied for the half-filled system with N =L /2 particles. Using large L asymptotics of Bethe ansatz formulas for the eigenstates, exact expressions depending explicitly on the rescaled time t /L3 /2 are obtained for the average and two-point function of the local density, and for the current fluctuations for simple (stationary, flat and step) initial conditions, relating previous results for the infinite system to stationary large deviations. The final formulas have a nice interpretation in terms of a functional integral with the action of a scalar field in a linear potential.

  4. Finite-Time Fluctuations for the Totally Asymmetric Exclusion Process.

    PubMed

    Prolhac, Sylvain

    2016-03-01

    The one-dimensional totally asymmetric simple exclusion process, a Markov process describing classical hard-core particles hopping in the same direction, is considered on a periodic lattice of L sites. The relaxation to the nonequilibrium steady state, which occurs on the time scale t∼L^{3/2} for large L, is studied for the half-filled system with N=L/2 particles. Using large L asymptotics of Bethe ansatz formulas for the eigenstates, exact expressions depending explicitly on the rescaled time t/L^{3/2} are obtained for the average and two-point function of the local density, and for the current fluctuations for simple (stationary, flat and step) initial conditions, relating previous results for the infinite system to stationary large deviations. The final formulas have a nice interpretation in terms of a functional integral with the action of a scalar field in a linear potential. PMID:26991165

  5. Primarily nonlinear effects observed in a driven asymmetrical vibrating wire

    NASA Astrophysics Data System (ADS)

    Hanson, Roger J.; Macomber, H. Kent; Morrison, Andrew C.; Boucher, Matthew A.

    2005-01-01

    The purpose of the work reported here is to further experimentally explore the wide variety of behaviors exhibited by driven vibrating wires, primarily in the nonlinear regime. When the wire is driven near a resonant frequency, it is found that most such behaviors are significantly affected by the splitting of the resonant frequency and by the existence of a ``characteristic'' axis associated with each split frequency. It is shown that frequency splitting decreases with increasing wire tension and can be altered by twisting. Two methods are described for determining the orientation of characteristic axes. Evidence is provided, with a possible explanation, that each axis has the same orientation everywhere along the wire. Frequency response data exhibiting nonlinear generation of transverse motion perpendicular to the driving direction, hysteresis, linear generation of perpendicular motion (sometimes tubular), and generation of motion at harmonics of the driving frequency are exhibited and discussed. Also reported under seemingly unchanging conditions are abrupt large changes in the harmonic content of the motion that sometimes involve large subharmonics and harmonics thereof. Slow transitions from one stable state of vibration to another and quasiperiodic motions are also exhibited. Possible musical significance is discussed. .

  6. Service quality and asymmetric information in the regulation of monopolies: The Chilean electricity distribution industry

    NASA Astrophysics Data System (ADS)

    Melo, Oscar Alfredo

    This study is an enquiry about the role that service quality, asymmetric information, scope of regulation and regulator's preferences play in the regulation of monopolies, with an application to the case of the Chilean electricity distribution industry. In Chapter 1, I present the problem of regulating a monopolist and introduce the special conditions that the electricity sector has. Later I discuss the main characteristics of the electricity system that operates in Chile. The literature on regulation is reviewed in Chapter 2. A special emphasis is given to the problems of quality and information, and the lack of its proper joint treatment. In Chapter 3, I develop four theoretical models of regulation that explicitly consider the regulation of price and quality versus price-only regulation, and a symmetric versus asymmetric information structure where only the regulator knows its true costs. In these models, I also consider the effect of a regulator that may have a preference between consumers and the regulated monopolistic firms. I conclude that with symmetric information and independent of the scope of regulation, having a regulator that prefers consumers or producers does not affect the efficiency of the outcome. I also show that the regulator's inability to set quality, thus regulating only price, leads to an inefficient outcome, away from the first best solution that can be achieved by regulating both price and quality, even with asymmetric information, as long as the regulator does not have a "biased" preference for consumers or the monopolistic producers. If the regulator has a "bias," then the equilibrium will be inefficient with asymmetric information. But the effect on equilibrium price and quality depends on the direction of the effect of quality on the marginal effect of price in demand. More importantly, no closed-form solution can be derived unless drastic simplifications are made. To further investigate the outcome of the models, I use numerical

  7. The asymptotic asymmetric-top rotational partition function

    NASA Astrophysics Data System (ADS)

    Watson, James K. G.

    The high-temperature asymptotic expansion of the rotational partition function of a rigid asymmetric-top molecule can be written in the form where g is the mean nuclear statistical weight and gζ is a nuclear statistical weight factor associated with the principal axis ζ. The asymptotic expansion of Q', which is calculated by two different methods, is expressed in the formulation of McDowell as where tMPH1377_images Here, α, β and γ are the dimensionless temperature-reduced rotational constants hcA/kT, hcB/kT and hcC/kT, and each sum is over the three cyclic permutations of (α, β, γ). For the Q'ζ, the principal asymptotic approximations tMPH1377_images are obtained, confirming results in the 1955 dissertation of Woolley.

  8. On the wake flow of asymmetrically beveled trailing edges

    NASA Astrophysics Data System (ADS)

    Guan, Yaoyi; Pröbsting, Stefan; Stephens, David; Gupta, Abhineet; Morris, Scott C.

    2016-05-01

    Trailing edge and wake flows are of interest for a wide range of applications. Small changes in the design of asymmetrically beveled or semi-rounded trailing edges can result in significant difference in flow features which are relevant for the aerodynamic performance, flow-induced structural vibration and aerodynamically generated sound. The present study describes in detail the flow field characteristics around a family of asymmetrically beveled trailing edges with an enclosed trailing-edge angle of 25° and variable radius of curvature R. The flow fields over the beveled trailing edges are described using data obtained by particle image velocimetry (PIV) experiments. The flow topology for different trailing edges was found to be strongly dependent on the radius of curvature R, with flow separation occurring further downstream as R increases. This variation in the location of flow separation influences the aerodynamic force coefficients, which were evaluated from the PIV data using a control volume approach. Two-point correlations of the in-plane velocity components are considered to assess the structure in the flow field. The analysis shows large-scale coherent motions in the far wake, which are associated with vortex shedding. The wake thickness parameter yf is confirmed as an appropriate length scale to characterize this large-scale roll-up motion in the wake. The development in the very near wake was found to be critically dependent on R. In addition, high-speed PIV measurements provide insight into the spectral characteristics of the turbulent fluctuations. Based on the time-resolved flow field data, the frequency range associated with the shedding of coherent vortex pairs in the wake is identified. By means of time-correlation of the velocity components, turbulent structures are found to convect from the attached or separated shear layers without distinct separation point into the wake.

  9. Recent Observations of Human-induced Asymmetric Effects on Climate in Very High-Altitude Area

    PubMed Central

    Lu, Heli; Liu, Guifang

    2014-01-01

    Like urban heat islands (UHI), human-induced land degradation (HLD) is a phenomenon attributed to human activities, but this phenomenon occurs in non-urban areas. Although a large body of work has demonstrated that land-cover change influences local climate systems, little work has been done on separating the impact of HLD from naturally-occurring fluctuations in very high-altitude areas. We developed an innovative NDVI-difference method in order to evaluate HLD effects upon the climate system in the central Tibet Plateau. The results show that the minimum temperature increased at a significantly faster pace than the maximum temperature in the growing season at HLD meteorological stations, but this was reversed at stations with natural forces only. Further analysis revealed that abrupt changes of minimum temperature occurred five years earlier and amplitudes of these changes were 1.4 times larger than at stations with natural forces only. Therefore, our results complement other evidence that points to the fact that local effects from UHI contribute to climatic asymmetry observed between minimum and maximum temperature trends. Accordingly, we stress the need for consideration of non-urban factors from anthropogenic activities, such as human-induced land degradation, in understanding these asymmetric diurnal changes. PMID:24489643

  10. Recent observations of human-induced asymmetric effects on climate in very high-altitude area.

    PubMed

    Lu, Heli; Liu, Guifang

    2014-01-01

    Like urban heat islands (UHI), human-induced land degradation (HLD) is a phenomenon attributed to human activities, but this phenomenon occurs in non-urban areas. Although a large body of work has demonstrated that land-cover change influences local climate systems, little work has been done on separating the impact of HLD from naturally-occurring fluctuations in very high-altitude areas. We developed an innovative NDVI-difference method in order to evaluate HLD effects upon the climate system in the central Tibet Plateau. The results show that the minimum temperature increased at a significantly faster pace than the maximum temperature in the growing season at HLD meteorological stations, but this was reversed at stations with natural forces only. Further analysis revealed that abrupt changes of minimum temperature occurred five years earlier and amplitudes of these changes were 1.4 times larger than at stations with natural forces only. Therefore, our results complement other evidence that points to the fact that local effects from UHI contribute to climatic asymmetry observed between minimum and maximum temperature trends. Accordingly, we stress the need for consideration of non-urban factors from anthropogenic activities, such as human-induced land degradation, in understanding these asymmetric diurnal changes. PMID:24489643

  11. Bilaterally asymmetric effects of quantitative trait loci (QTLs): QTLs that affect laxity in the right versus left coxofemoral (hip) joints of the dog (Canis familiaris).

    PubMed

    Chase, Kevin; Lawler, Dennis F; Adler, Fred R; Ostrander, Elaine A; Lark, Karl G

    2004-01-30

    In dogs hip joint laxity that can lead to degenerative joint disease (DJD) is frequent and heritable, providing a genetic model for some aspects of the human disease. We have used Portuguese water dogs (PWDs) to identify Quantitative trait loci (QTLs) that regulate laxity in the hip joint. A population of 286 PWDs, each characterized by ca. 500 molecular genetic markers, was analyzed for subluxation of the hip joint as measured by the Norberg angle, a quantitative radiographic measure of laxity. A significant directed asymmetry was observed, such that greater laxity was observed in the left than the right hip. This asymmetry was not heritable. However, the average Norberg angle was highly heritable as were the Norberg angles of either the right or left hips. After correction for pedigree effects, two QTLs were identified using the metrics of the left and right hips as separate data sets. Both are on canine chromosome 1 (CFA1), separated by about 95 Mb. One QTL, associated with the SSR marker FH2524 was significant for the left, but not the right hip. The other, associated with FH2598, was significant for the right but not the left hip. For both QTLs, some extreme phenotypes were best explained by specific interactions between haplotypes. PMID:14708095

  12. Bilaterally Asymmetric Effects of Quantitative Trait Loci (QTLs): QTLs That Affect Laxity in the Right Versus Left Coxofemoral (Hip) Joints of the Dog (Canis familiaris)

    PubMed Central

    Chase, Kevin; Lawler, Dennis F.; Adler, Fred R.; Ostrander, Elaine A.; Lark, Karl G.

    2009-01-01

    In dogs hip joint laxity that can lead to degenerative joint disease (DJD) is frequent and heritable, providing a genetic model for some aspects of the human disease. We have used Portuguese water dogs (PWDs) to identify Quantitative trait loci (QTLs) that regulate laxity in the hip joint.A population of 286 PWDs, each characterized by ca. 500 molecular genetic markers, was analyzed for subluxation of the hip joint as measured by the Norberg angle, a quantitative radiographic measure of laxity. A significant directed asymmetry was observed, such that greater laxity was observed in the left than the right hip. This asymmetry was not heritable. However, the average Norberg angle was highly heritable as were the Norberg angles of either the right or left hips. After correction for pedigree effects, two QTLs were identified using the metrics of the left and right hips as separate data sets. Both are on canine chromosome 1 (CFA1), separated by about 95 Mb. One QTL, associated with the SSR marker FH2524 was significant for the left, but not the right hip. The other, associated with FH2598, was significant for the right but not the left hip. For both QTLs, some extreme phenotypes were best explained by specific interactions between haplotypes. PMID:14708095

  13. Asymmetrical Effects of Introduced Bullfrogs (Rana catesbeiana) on Native Ranid Frogs in Oregon

    USGS Publications Warehouse

    Pearl, C.A.; Adams, M.J.; Bury, R.B.; McCreary, B.

    2004-01-01

    Introduced American Bullfrogs (Rana catesbeiana) have become widely established in the Pacific Northwest over the last century and are thought to be an important predator of native amphibians throughout the western United States. The Northern Red-Legged Frog (Rana aurora aurora) and Oregon Spotted Frog (Rana pretiosa) historically coexisted in portions of the Pacific Northwest now invaded by R. catesbeiana, but R. pretiosa has declined more severely than R. a. aurora. We investigated whether microhabitat and behavioral differences that facilitate sympatric coexistence of the natives predict which species is more susceptible to predation by introduced R. catesbeiana. Our laboratory experiments demonstrate that R. catesbeiana adults prefer aquatic microhabitats, that R. pretiosa juveniles are more aquatic than R. a. aurora, and that adult R. catesbeiana consume more R. pretiosa than R. a. aurora juveniles. Mean and maximum jump distances of R. pretiosa were shorter than equally sized R. a. aurora, and the difference between these two species increased with larger frog sizes. Our examination of field survey data indicates that R. pretiosa coexist with R. catesbeiana less frequently than R. a. aurora. We conclude that R. catesbeiana is a greater threat to survival of R. pretiosa than to R. a. aurora and suggest that microhabitat use and escape abilities of native ranid frogs may be linked to this asymmetrical effect. Analysis of behavioral and microhabitat differences among related native species may be a useful tool in predicting the effects of introduced predators on amphibians and can assist in developing conservation priorities for these species.

  14. Asymmetrical effects of introduced Rana catesbeiana on native ranid frogs in Oregon, USA

    USGS Publications Warehouse

    Pearl, Christopher A.; Adams, Michael J.; Bury, R. Bruce; McCreary, B.

    2004-01-01

    Introduced American Bullfrogs (Rana catesbeiana) have become widely established in the Pacific Northwest over the last century and are thought to be an important predator of native amphibians throughout the western United States. The Northern Red-Legged Frog (Rana aurora aurora) and Oregon Spotted Frog (Rana pretiosa) historically coexisted in portions of the Pacific Northwest now invaded by R. catesbeiana, but R. pretiosa has declined more severely than R. a. aurora. We investigated whether microhabitat and behavioral differences that facilitate sympatric coexistence of the natives predict which species is more susceptible to predation by introduced R. catesbeiana. Our laboratory experiments demonstrate that R. catesbeiana adults prefer aquatic microhabitats, that R. pretiosa juveniles are more aquatic than R. a. aurora, and that adult R. catesbeiana consume more R. pretiosa than R. a. aurora juveniles. Mean and maximum jump distances of R. pretiosa were shorter than equally sized R. a. aurora, and the difference between these two species increased with larger frog sizes. Our examination of field survey data indicates that R. pretiosa coexist with R. catesbeiana less frequently than R. a. aurora. We conclude that R. catesbeiana is a greater threat to survival of R. pretiosa than to R. a. aurora and suggest that microhabitat use and escape abilities of native ranid frogs may be linked to this asymmetrical effect. Analysis of behavioral and microhabitat differences among related native species may be a useful tool in predicting the effects of introduced predators on amphibians and can assist in developing conservation priorities for these species.

  15. Measuring Website Quality: Asymmetric Effect of User Satisfaction

    ERIC Educational Resources Information Center

    Kincl, Tomas; Strach, Pavel

    2012-01-01

    Website quality measurement tools have been largely static and have struggled to determine relevant attributes of user satisfaction. This study compares and contrasts attributes of user satisfaction based on usability guidelines seeking to identify practical easy-to-administer measurement tools. The website users assessed business school homepages…

  16. The Nuclear Matrix Protein Megator Regulates Stem Cell Asymmetric Division through the Mitotic Checkpoint Complex in Drosophila Testes.

    PubMed

    Liu, Ying; Singh, Shree Ram; Zeng, Xiankun; Zhao, Jiangsha; Hou, Steven X

    2015-12-01

    In adult Drosophila testis, asymmetric division of germline stem cells (GSCs) is specified by an oriented spindle and cortically localized adenomatous coli tumor suppressor homolog 2 (Apc2). However, the molecular mechanism underlying these events remains unclear. Here we identified Megator (Mtor), a nuclear matrix protein, which regulates GSC maintenance and asymmetric division through the spindle assembly checkpoint (SAC) complex. Loss of Mtor function results in Apc2 mis-localization, incorrect centrosome orientation, defective mitotic spindle formation, and abnormal chromosome segregation that lead to the eventual GSC loss. Expression of mitotic arrest-deficient-2 (Mad2) and monopolar spindle 1 (Mps1) of the SAC complex effectively rescued the GSC loss phenotype associated with loss of Mtor function. Collectively our results define a new role of the nuclear matrix-SAC axis in regulating stem cell maintenance and asymmetric division. PMID:26714316

  17. The Nuclear Matrix Protein Megator Regulates Stem Cell Asymmetric Division through the Mitotic Checkpoint Complex in Drosophila Testes

    PubMed Central

    Zeng, Xiankun; Zhao, Jiangsha; Hou, Steven X.

    2015-01-01

    In adult Drosophila testis, asymmetric division of germline stem cells (GSCs) is specified by an oriented spindle and cortically localized adenomatous coli tumor suppressor homolog 2 (Apc2). However, the molecular mechanism underlying these events remains unclear. Here we identified Megator (Mtor), a nuclear matrix protein, which regulates GSC maintenance and asymmetric division through the spindle assembly checkpoint (SAC) complex. Loss of Mtor function results in Apc2 mis-localization, incorrect centrosome orientation, defective mitotic spindle formation, and abnormal chromosome segregation that lead to the eventual GSC loss. Expression of mitotic arrest-deficient-2 (Mad2) and monopolar spindle 1 (Mps1) of the SAC complex effectively rescued the GSC loss phenotype associated with loss of Mtor function. Collectively our results define a new role of the nuclear matrix-SAC axis in regulating stem cell maintenance and asymmetric division. PMID:26714316

  18. On the absence of asymmetric wakes for periodically plunging finite wings

    NASA Astrophysics Data System (ADS)

    Calderon, D. E.; Cleaver, D. J.; Gursul, I.; Wang, Z.

    2014-07-01

    It has previously been shown that, at high Strouhal numbers, oscillating airfoils can produce deflected jets that can create very high lift-coefficients for otherwise symmetric scenarios. These deflected jets form through pairing of the trailing-edge vortices to create asymmetric vortex couples that self-propel at an angle to the freestream, resulting in an asymmetric flow field and non-zero lift. In this paper results are presented that indicate these high-lift deflected jets cannot form for finite wings. Instead of the straight vortex tubes that pair and convect at an angle to the freestream observed for effectively infinite wings, finite wings exhibit vortex tubes that break into two branches near the tip forming double helix structures. One branch connects with the last vortex; one branch connects with the next vortex. This creates a long "daisy chain" of interconnected trailing edge vortices forming a long series of vortex loops. These symmetric flow fields are shown to persist for finite wings even to Strouhal numbers more than twice those required to produce asymmetric wakes on plunging airfoils. Two contributing reasons are discussed for why deflected jets are not observed. First the tip vortex creates three-dimensionality that discourages vortex coupling. Second, the symmetry of the circulation of the interconnected vortex loops, which has been confirmed by the experiments, is a natural consequence of the vortex topology. Therefore, the asymmetry in trailing edge vortex strength previously observed as characteristic of deflected jets cannot be supported for finite wings.

  19. Numerical solution of the asymmetric water impact of a wedge in three degrees of freedom

    NASA Astrophysics Data System (ADS)

    Ghazizade-Ahsaee, H.; Nikseresht, A. H.

    2013-06-01

    Impact problems associated with water entry have important applications in various aspects of naval architecture and ocean engineering. Estimation of hydrodynamic impact forces especially during the first instances after the impact is very important and is of interest. Since the estimation of hydrodynamic impact load plays an important role in safe design and also in evaluation of structural weight and costs, it is better to use a reliable and accurate prediction method instead of a simple estimation resulted by analyzing methods. In landing of flying boats, some phenomena such as weather conditions and strong winds can cause asymmetric instead of symmetric descent. In this paper, a numerical simulation of the asymmetric impact of a wedge, as the step of a flying boat, considering dynamic equations in two-phase flow is taken into account. The dynamic motion of the wedge in two-phase flow is solved based on finite volume method with volume of fluid (VOF) scheme considering dynamic equations. Then the effects of different angles of impact and water depth on the velocity change and slamming forces in an asymmetric impact are investigated. The comparison between the simulation results and experimental data verifies the accuracy of the method applied in the present study.

  20. Photodissociation dynamics of tryptophan and the implication of asymmetric photolysis

    SciTech Connect

    Tseng, Chien-Ming; Dyakov, Yuri A.; Huang, Huai Ching; Huang, Kuan Yu; Lee, Yuan T.; Ni, Chi-Kung; Chiang, Su-Yu

    2010-08-21

    Photodissociation of amino acid tryptophan in a molecular beam at wavelengths of 212.8 and 193 nm, corresponding to excitation to the second and third absorption bands, was investigated using multimass ion imaging techniques. The respective wavelengths also represent excitation to the edge of a positive circular dichroism band and the center of a negative circular dichroism band of L-tryptophan. Only one dissociation channel was observed at both photolysis wavelengths: C{sub 8}NH{sub 6}CH{sub 2}CHNH{sub 2}COOH{yields}C{sub 8}NH{sub 6}CH{sub 2}+CHNH{sub 2}COOH. Dissociation rates were found to be 1.3x10{sup 6} and 5x10{sup 6} s{sup -1} at the respective wavelengths. Comparison to theoretical calculation indicates that dissociation occurs on the ground state after internal conversion. Implication of asymmetric photolysis is discussed.

  1. The role of upper lateral cartilage in dorsal reconstruction after hump excision: section 1. Spreader flap modification with asymmetric mattress suture and extension of the spreading effect by cartilage graft.

    PubMed

    Manavbaşı, Y Ilker; Başaran, Ihsan

    2011-08-01

    A spreader flap, or autospreader flap, is a flap used for dorsal reconstruction in primary rhinoplasty after cartilage dorsum excision. Despite its significant advantages, the spreader flap also has distinct shortcomings. The most common problem encountered in using a spreader flap is the technique's inability to provide adequate dorsal width compared with spreader grafts. Additionally, the use of a spreader flap has not been described for special cases such as crooked noses, cases with minimal dorsal humps, and secondary cases. This report presents the authors' modification of the spreader flap technique to expand its indications and extend the spreader effect down to the entire dorsum. This modification positions and fixes the medial borders of the upper lateral cartilages (ULCs) on both sides of the septum by asymmetric mattress sutures. Using the ULCs without folding affords the opportunity to restore a dorsum with sufficient width. Different entry and exit points of the suture help to maintain the cartilage substance horizontally rather than folded as in the conventional spreader flap technique. Another drawback of the spreader flap technique is its inability to address the lower third of the dorsum when ULCs do not extend down to the anterior septal angle (ASA). In these cases, attempts were made to extend the spreader effect by placing two small cartilage grafts on both sides of the ASA. Over a period of 2 years, the authors operated on 169 patients. For 81 of these patients, the modified spreader flap alone was used, and for the remaining 88 patients, both the modified spreader flap technique and ASA grafting (combined modification) were used. During a mean follow-up period of 17 months, no narrowing in the middle nasal dorsum and no inner valve deficiencies were seen in any of the cases. PMID:21298515

  2. The role of asymmetric transfer in the evaluation of voice generation and recognition systems

    NASA Astrophysics Data System (ADS)

    Damos, D. L.

    1987-02-01

    The results of five experiments examining the effect of voice generation and recognition systems on dual task performance are presented. The extent to which asymmetric transfer biased the data in three of these experiments is determined by using statistical techniques and by comparing the data to the results of between subjects experiments. Generally, subjects performed task combinations better when stimuli for one of the tasks was presented auditorily using a voice generation system rather than visually on a display screen. In contrast, the use of a voice recognition system did not result in better dual task performance than the use of more conventional input devices.

  3. The basic mechanics of bipedal walking lead to asymmetric behavior.

    PubMed

    Gregg, Robert D; Degani, Amir; Dhaher, Yasin; Lynch, Kevin M

    2011-01-01

    This paper computationally investigates whether gait asymmetries can be attributed in part to basic bipedal mechanics independent of motor control. Using a symmetrical rigid-body model known as the compass-gait biped, we show that changes in environmental or physiological parameters can facilitate asymmetry in gait kinetics at fast walking speeds. In the environmental case, the asymmetric family of high-speed gaits is in fact more stable than the symmetric family of low-speed gaits. These simulations suggest that lower extremity mechanics might play a direct role in functional and pathological asymmetries reported in human walking, where velocity may be a common variable in the emergence and growth of asymmetry. PMID:22275657

  4. Investigation of an Asymmetric B Factory in the PEP Tunnel

    SciTech Connect

    Chattapadhyay, A.; Hitlin, D.; Porter, F.; Chin, Y.H.; Dell'Orco, D.; Forest, E.; Furman, M.; Garren, A.A.; Hearty, C.; Jacob, A.; Kennedy, K.; Kim, K.; Lambertson, G.; Oddone, P.; Ronan, M.; Sessler, A.; Taylor, C.; Voelker, F.; Zisman, M.; Barletta, W.; Allen, M.; Bane, K.; Bloom, E.; Brenkus, F.; Brown, K.; Corbett, J.; Cornacchia, M.; Coupal, D.; Davies-White, W.; DeStaebler, H.; Donald, M.; Dorfan, J.; Hsu, I.; Hutton, A.; Jenkins, T.; Kozanecki, W.; Lisin, A.; Loew, G.; Miller, R.; Morton, P.; Pellegrin, J.-L.; Raubenheimer, T.; Rees, J.; Ritson, D.; Ruth, R.; Saab, A.; Savage, W.; Schwarz, H.; Seeman, J.; Thompson, K.; Weidner, H.; Wilson, P.; Sullivan, M.; Jackson, G.; Hertzbach, S.; Tennyson, J.; Zholents, A.; Fitze, H.

    1990-03-01

    This report addresses the feasibility of designing and constructing an asymmetric B-factory based on the PEP storage ring at SLAC that can begin operation at a luminosity of 3 X 10{sup 33} cm{sup -2}s{sup -1} and could ultimately reach even higher luminosity. Such a facility, operating at the {gamma}(4S) resonance, could be used to study mixing, rare decays, and CP violation in the B{bar B} system, and could also study tau and charm physics. The essential accelerator physics, engineering and technology issues that must be addressed to successfully build this exciting and challenging facility are identified, and possible solutions, or R and D activities that will reasonable lead to such solutions, are described.

  5. Effect of asymmetrical flow field-flow fractionation channel geometry on separation efficiency.

    PubMed

    Ahn, Ji Yeon; Kim, Ki Hun; Lee, Ju Yong; Williams, P Stephen; Moon, Myeong Hee

    2010-06-11

    The separation efficiencies of three different asymmetrical flow field-flow fractionation (AF4) channel designs were evaluated using polystyrene latex standards. Channel breadth was held constant for one channel (rectangular profile), and was reduced either linearly (trapezoidal profile) or exponentially (exponential profile) along the length for the other two. The effective void volumes of the three channel types were designed to be equivalent. Theoretically, under certain flow conditions, the mean channel flow velocity of the exponential channel could be arranged to remain constant along the channel length, thereby improving separation in AF4. Particle separation obtained with the exponential channel was compared with particle separation obtained with the trapezoidal and rectangular channels. We demonstrated that at a certain flow rate condition (outflow/inflow rate=0.2), the exponential channel design indeed provided better performance with respect to the separation of polystyrene nanoparticles in terms of reducing band broadening. While the trapezoidal channel exhibited a little poorer performance than the exponential, the strongly decreasing mean flow velocity in the rectangular channel resulted in serious band broadening, a delay in retention time, and even failure of larger particles to elute. PMID:20439106

  6. Imperfect asymmetry: The mechanism governing asymmetric partitioning of damaged cellular components during mitosis

    PubMed Central

    Pattabiraman, Sundararaghavan; Kaganovich, Daniel

    2014-01-01

    Aging is universally associated with organism-wide dysfunction and a decline in cellular fitness. From early development onwards, the efficiency of self-repair, energy production, and homeostasis all decrease. Due to the multiplicity of systems that undergo agingrelated decline, the mechanistic basis of organismal aging has been difficult to pinpoint. At the cellular level, however, recent work has provided important insight. Cellular aging is associated with the accumulation of several types of damage, in particular damage to the proteome and organelles. Groundbreaking studies have shown that replicative aging is the result of a rejuvenation mechanism that prevents the inheritance of damaged components during division, thereby confining the effects of aging to specific cells, while removing damage from others. Asymmetric inheritance of misfolded and aggregated proteins, as well as reduced mitochondria, has been shown in yeast. Until recently, however, it was not clear whether a similar mechanism operates in mammalian cells, which were thought to mostly divide symmetrically. Our group has recently shown that vimentin establishes mitotic polarity in immortalized mammalian cells, and mediates asymmetric partitioning of multiple factors through direct interaction. These findings prompt a provocative hypothesis: that intermediate filaments serve as asymmetric partitioning modules or “sponges” that, when expressed prior to mitosis, can “clean” emerging cells of the damage they have accumulated. PMID:25941938

  7. Asymmetric dispersal structures a riverine metapopulation of the freshwater pearl mussel Margaritifera laevis

    PubMed Central

    Terui, Akira; Miyazaki, Yusuke; Yoshioka, Akira; Kaifu, Kenzo; Matsuzaki, Shin-ichiro S; Washitani, Izumi

    2014-01-01

    Unidirectional water flow results in the downstream-biased, asymmetric dispersal of many riverine organisms. However, little is known of how asymmetric dispersal influences riverine population structure and dynamics, limiting our ability to properly manage riverine organisms. A metapopulation of the freshwater pearl mussel Margaritifera laevis may be sensitive to river currents because mussels are repeatedly exposed to downstream drift during floods—a parasitic life stage is the only, limited period (∼40 days) during which larvae (glochidia) can move upstream with the aid of host fish. We hypothesized that water-mediated dispersal would overwhelm upstream dispersal via host fish, and therefore, that upstream subpopulations play a critical role as immigrant sources. To test this hypothesis, we examined the effects of both up- and downstream immigrant sources on the size of target subpopulations in the Shubuto River system, Hokkaido, Japan. We found that target subpopulation size was dependent on the upstream distribution range of reproductive subpopulations and the number of upstream tributaries, which are proxies for the number of potential immigrants moving downstream. In contrast, little influence was observed of downstream immigrant sources (proximity to downstream reproductive subpopulations). These results were consistent even after accounting for local environments and stream size. Our finding suggests that upstream subpopulations can be disproportionately important as immigrant sources when dispersal is strongly asymmetric. PMID:25247058

  8. Asymmetric intergroup bullying: The enactment and maintenance of societal inequality at work

    PubMed Central

    Soylu, Soydan; Sheehy-Skeffington, Jennifer

    2015-01-01

    What does inequality mean for dysfunctional organizational behaviours, such as workplace bullying? This article argues that workplace bullying can be understood as a manifestation of intergroup dynamics originating beyond the organization. We introduce the construct of asymmetric intergroup bullying: the disproportionate mistreatment of members of low status groups, with the intended effect of enhancing the subordination of that group in society at large. Analysis of data from 38 interviews with public and private sector workers in Turkey depicts a pattern of asymmetric intergroup bullying, undertaken to achieve organizational and broader sociopolitical goals. Respondents reported bullying acts used to get rid of unwanted personnel, with the goal of avoiding severance pay, or of removing supporters of the former government from positions of political and economic influence. Bullying was also described as working towards the dominance of the sociocultural worldview of one political group over another. We discuss asymmetric intergroup bullying as one mechanism through which acute intergroup hierarchy in the broader society corrupts management practice and employee interactions, in turn exacerbating economic inequality along group lines. PMID:26819482

  9. Asymmetric Hearing During Development: The Aural Preference Syndrome and Treatment Options.

    PubMed

    Gordon, Karen; Henkin, Yael; Kral, Andrej

    2015-07-01

    Deafness affects ∼2 in 1000 children and is one of the most common congenital impairments. Permanent hearing loss can be treated by fitting hearing aids. More severe to profound deafness is an indication for cochlear implantation. Although newborn hearing screening programs have increased the identification of asymmetric hearing loss, parents and caregivers of children with single-sided deafness are often hesitant to pursue therapy for the deaf ear. Delayed intervention has consequences for recovery of hearing. It has long been reported that asymmetric hearing loss/single-sided deafness compromises speech and language development and educational outcomes in children. Recent studies in animal models of deafness and in children consistently show evidence of an "aural preference syndrome" in which single-sided deafness in early childhood reorganizes the developing auditory pathways toward the hearing ear, with weaker central representation of the deaf ear. Delayed therapy consequently compromises benefit for the deaf ear, with slow rates of improvement measured over time. Therefore, asymmetric hearing needs early identification and intervention. Providing early effective stimulation in both ears through appropriate fitting of auditory prostheses, including hearing aids and cochlear implants, within a sensitive period in development has a cardinal role for securing the function of the impaired ear and for restoring binaural/spatial hearing. The impacts of asymmetric hearing loss on the developing auditory system and on spoken language development have often been underestimated. Thus, the traditional minimalist approach to clinical management aimed at 1 functional ear should be modified on the basis of current evidence. PMID:26055845

  10. The neural dynamic mechanisms of asymmetric switch costs in a combined Stroop-task-switching paradigm.

    PubMed

    Wu, Shanshan; Hitchman, Glenn; Tan, Jinfeng; Zhao, Yuanfang; Tang, Dandan; Wang, Lijun; Chen, Antao

    2015-01-01

    Switch costs have been constantly found asymmetrical when switching between two tasks of unequal dominance. We used a combined Stroop-task-switching paradigm and recorded electroencephalographic (EEG) signals to explore the neural mechanism underlying the phenomenon of asymmetrical switch costs. The results revealed that a fronto-central N2 component demonstrated greater negativity in word switch (cW) trials relative to word repeat (wW) trials, and both First P3 and P3b components over the parieto-central region exhibited greater positivity in color switch (wC) trials relative to color repeat (cC) trials, whereas a contrasting switch-related fronto-central SP effect was found to have an opposite pattern for each task. Moreover, the time-frequency analysis showed a right-frontal lower alpha band (9-11 Hz) modulation in the word task, whereas a fronto-central upper alpha band (11-13 Hz) modulation was exclusively found in the color task. These results provide evidence for dissociable neural processes, which are related to inhibitory control and endogenous control, contributing to the generation of asymmetrical switch costs. PMID:25989933