Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1 GeV2. II. e p →e π0p

NASA Astrophysics Data System (ADS)

Bosted, P. E.; Kim, A.; Adhikari, K. P.; Adikaram, D.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Badui, R. A.; Ball, J.; Balossino, I.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Fegan, S.; Fersch, R.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Fradi, A.; Ghandilyan, Y.; Gilfoyle, G. P.; Girod, F. X.; Glazier, D. I.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Hakobyan, H.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Hicks, K.; Hollis, G.; Holtrop, M.; Hughes, S. M.; Ireland, D. G.; Isupov, E. L.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joo, K.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, W.; Klei, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McCracken, M. E.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V. I.; Montgomery, R. A.; Movsisyan, A.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Ni, A.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Saini, M. S.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2017-03-01

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π0 electroproduction reaction γ*p →p π0 , expanding an analysis of the γ*p →n π+ reaction from the same experiment. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic ranges covered are 1.1 target asymmetries were found to generally be greater than zero, with relatively modest ϕ* dependence. The target asymmetries exhibit very strong ϕ* dependence, with a change in sign occurring between results at low W and high W , in contrast to π+ electroproduction. Reasonable agreement is found with phenomenological fits to previous data for W <1.6 GeV, but significant differences are seen at higher W . When combined with cross-sectional measurements, as well as π+ observables, the present results will provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q2, for resonances with masses as high as 2.4 GeV.

Coupling between Mercury and its nightside magnetosphere: Cross-tail current sheet asymmetry and substorm current wedge formation

NASA Astrophysics Data System (ADS)

Poh, Gangkai; Slavin, James A.; Jia, Xianzhe; Raines, Jim M.; Imber, Suzanne M.; Sun, Wei-Jie; Gershman, Daniel J.; DiBraccio, Gina A.; Genestreti, Kevin J.; Smith, Andy W.

2017-08-01

We analyzed MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) magnetic field and plasma measurements taken during 319 crossings of Mercury's cross-tail current sheet. We found that the measured BZ in the current sheet is higher on the dawnside than the duskside by a factor of ≈3 and the asymmetry decreases with downtail distance. This result is consistent with expectations based upon MHD stress balance. The magnetic fields threading the more stretched current sheet in the duskside have a higher plasma beta than those on the dawnside, where they are less stretched. This asymmetric behavior is confirmed by mean current sheet thickness being greatest on the dawnside. We propose that heavy planetary ion (e.g., Na+) enhancements in the duskside current sheet provides the most likely explanation for the dawn-dusk current sheet asymmetries. We also report the direct measurement of Mercury's substorm current wedge (SCW) formation and estimate the total current due to pileup of magnetic flux to be ≈11 kA. The conductance at the foot of the field lines required to close the SCW current is found to be ≈1.2 S, which is similar to earlier results derived from modeling of Mercury's Region 1 field-aligned currents. Hence, Mercury's regolith is sufficiently conductive for the current to flow radially then across the surface of Mercury's highly conductive iron core. Mercury appears to be closely coupled to its nightside magnetosphere by mass loading of upward flowing heavy planetary ions and electrodynamically by field-aligned currents that transfer momentum and energy to the nightside auroral oval crust and interior. Heavy planetary ion enhancements in Mercury's duskside current sheet provide explanation for cross-tail asymmetries found in this study. The total current due to the pileup of magnetic flux and conductance required to close the SCW current is found to be ≈11 kA and 1.2 S. Mercury is coupled to magnetotail by mass loading of heavy ions

The control of sequential aiming movements: the influence of practice and manual asymmetries on the one-target advantage.

PubMed

Lavrysen, Ann; Helsen, Werner F; Tremblay, Luc; Elliott, Digby; Adam, Jos J; Feys, Peter; Buekers, Martinus J

2003-04-01

The present experiment was conducted to explore the effect of practice on the one-target advantage in manual aiming, as well as asymmetries in intermanual transfer of training. Reaction and movement times for the first movement were longer in the 2-target than in the 1-target task, regardless of the amount of practice, hand preference and practice hand. When two movements were required, peak velocity was lower and, proportionally, more time was spent after peak velocity. Our kinematic results suggest that the one-target advantage is related to both predefined strategies as well as movement implementation processes during execution. Therefore, an integration of advance planning and on-line explanations for the one-target advantage is suggested. Regarding manual asymmetries, right-handers showed more transfer of training from the left to the right hand than vice versa. Left-handers exhibited a reversed pattern of asymmetric transfer of training to right-handers, but they were more disadvantaged using their non-dominant hand. These latter two findings have implications for models of manual asymmetry and upper limb control.

Measurement of the target-normal single-spin asymmetry in quasielastic scattering from the reaction He 3 ↑ ( e , e ' )

DOE PAGES

Zhang, Y. -W.; Long, E.; Mihovilovič, M.; ...

2015-10-22

We report the first measurement of the target single-spin asymmetry, Ay, in quasi-elastic scattering from the inclusive reaction 3He↑ (e,e') on a 3He gas target polarized normal to the lepton scattering plane. Assuming time-reversal invariance, this asymmetry is strictly zero for one-photon exchange. A non-zero A y can arise from the interference between the one- and two-photon exchange processes which is sensitive to the details of the sub-structure of the nucleon. An experiment recently completed at Jefferson Lab yielded asymmetries with high statistical precision at Q 2= 0.13, 0.46 and 0.97 GeV 2. These measurements demonstrate, for the first time,more » that the 3He asymmetry is clearly non-zero and negative with a statistical significance of (8-10)σ. Using measured proton-to- 3He cross-section ratios and the effective polarization approximation, neutron asymmetries of -(1-3)% were obtained. The neutron asymmetry at high Q 2 is related to moments of the Generalized Parton Distributions (GPDs). Our measured neutron asymmetry at Q 2=0.97 GeV 2 agrees well with a prediction based on two-photon exchange using a GPD model and in addition provides a new independent constraint on these distributions.« less

Target and beam-target spin asymmetries in exclusive pion electroproduction for Q2>1 GeV2 . I. e p →e π+n

NASA Astrophysics Data System (ADS)

Bosted, P. E.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; De Vita, R.; Deur, A.; De Sanctis, E.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Forest, T.; Fradi, A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Girod, F. X.; Gleason, C.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Hakobyan, H.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Jo, H. S.; Joo, K.; Joosten, S.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Lanza, L.; Net, L. A.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; McCracken, M. E.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Mokeev, V. I.; Montgomery, R. A.; Munevar, E.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Niccolai, S.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Peng, P.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rosner, G.; Rossi, P.; Schumacher, R. A.; Seder, E.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2017-03-01

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π+ electroproduction reaction γ*p →n π+ . The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic range covered is 1.1 target-spin asymmetries are observed over the entire W region. Reasonable agreement is found with phenomenological fits to previous data for W <1.6 GeV, but very large differences are seen at higher values of W . A generalized parton distributions (GPD)-based model is in poor agreement with the data. When combined with cross-sectional measurements, the present results provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q2, for resonances with masses as high as 2.4 GeV.

Target and beam-target spin asymmetries in exclusive pion electroproduction for Q 2 > 1 GeV 2 . I. e p → e π + n

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bosted, P. E.; Amaryan, M. J.; Anefalos Pereira, S.

2017-03-20

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π+ electroproduction reaction γ*p → nπ +. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic range covered is 1.1 < W < 3 GeV and 1 < Q 2 < 6GeV 2. Results were obtained for about 6000 bins in W, Q 2, cos(θ*), and Φ*. Except at forward angles, very large target-spin asymmetries are observed over the entire W region. Reasonable agreement is found with phenomenological fits to previousmore » data for W < 1.6 GeV, but very large differences are seen at higher values of W. Finally, a generalized parton distributions (GPD)-based model is in poor agreement with the data. When combined with cross-sectional measurements, the present results provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q 2, for resonances with masses as high as 2.4 GeV.« less

Current temporal asymmetry and the role of tides: Nan-Wan Bay vs. the Gulf of Elat

NASA Astrophysics Data System (ADS)

Ashkenazy, Yosef; Fredj, Erick; Gildor, Hezi; Gong, Gwo-Ching; Lee, Hung-Jen

2016-05-01

Nan-Wan Bay in Taiwan and the Gulf of Elat in Israel are two different coastal environments, and as such, their currents are expected to have different statistical properties. While Nan-Wan Bay is shallow, has three open boundaries, and is directly connected to the open ocean, the Gulf of Elat is deep, semi-enclosed, and connected to the Red Sea via the Straits of Tiran. Surface currents have been continuously measured with fine temporal (less than or equal to 1 h) and spatial resolution (less than or equal to 1 km) for more than a year in both environments using coastal radars (CODARs) that cover a domain of roughly 10 × 10 km. These measurements show that the currents in Nan-Wan Bay are much stronger than those in the Gulf of Elat and that the mean current field in Nan-Wan Bay exhibits cyclonic circulation, which is stronger in the summer; in the Gulf of Elat, the mean current field is directed southward and is also stronger during the summer. We have compared the statistical properties of the current speeds in both environments and found that both exhibit large spatial and seasonal variations in the shape parameter of the Weibull distribution. However, we have found fundamental and significant differences when comparing the temporal asymmetry of the current speed (i.e., the ratio between the time during which the current speed increases and the total time). While the Nan-Wan Bay currents are significantly asymmetric, those of the Gulf of Elat are not. We then extracted the tidal component of the Nan-Wan Bay currents and found that it is strongly asymmetric, while the asymmetry of tidally filtered currents is much weaker. We thus conclude that the temporal asymmetry of the Nan-Wan Bay currents reported here is due to the strong tides in the region. We show that the asymmetry ratio in Nan-Wan Bay varies spatially and seasonally: (i) the currents increase rapidly and decay slowly in the northern part of the domain and vice versa in the southern part, and (ii) the

Current temporal asymmetry and the role of tides: Nan-Wan Bay vs. the Gulf of Elat

NASA Astrophysics Data System (ADS)

Ashkenazy, Y.; Fredj, E.; Gildor, H.; Gong, G. C.; Lee, H. J.; Wu, C. R.

2016-02-01

Nan-Wan Bay in Taiwan and the Gulf of Elat in Israel are two different coastal environments and as such are expected to have different statistical properties of their currents. While the Nan-Wan Bay is shallow, has three open boundaries, and directly connected to the open ocean, the Gulf of Elat is deep, semi-enclosed, and connected to the Red Sea via the Straits of Tiran. High temporal (less or equal one hour) and spatial (less or equal one km) surface currents have been measured continuously for more than a year in both environments using Coastal Radars (CODARs) that cover a domain of roughly 10×10 kms. These measurements show that the currents in Nan-Wan Bay are much stronger than those in the Gulf of Elat and that the mean current field in Nan-Wan Bay exhibits cyclonic circulation, which is stronger in the summer; in the Gulf of Elat the mean current field is directed to south and is stronger during the summer. We have compared the statistical properties of the CODAR current speeds in both environments and found that both exhibit large spatial and seasonal variations in the shape parameter of the Weibull distribution. However, we have found fundamental and significant differences when comparing the temporal asymmetry of the current speed (i.e., the ratio between the time during which the current speed is increasing to the total time). While the Nan-Wan Bay currents are significantly asymmetric, those of the Gulf of Elat are not significantly asymmetric. We then extracted the tidal component of the Nan-Wan Bay currents and found that it is strongly asymmetric while the asymmetry of tidally-filtered currents is much weaker. We thus conclude that the temporal asymmetry of the Nan-Wan Bay currents reported here is due to the strong tides in the region. We show that the asymmetry ratio in the Nan-Wan Bay is varied spatially and seasonally: (i) currents increase rapidly and decay slowly in the northern part of the domain and vice versa in the southern part, and that

Target and beam-target spin asymmetries in exclusive pion electroproduction for Q 2 > 1 GeV 2 . II. e p → e π 0 p

DOE PAGES

Bosted, P. E.; Amaryan, M. J.; Anefalos Pereira, S.; ...

2017-03-20

Beam-target double-spin asymmetries and target single-spin asymmetries were measured for the exclusive π + electroproduction reaction γ*p→nπ +. The results were obtained from scattering of 6-GeV longitudinally polarized electrons off longitudinally polarized protons using the CEBAF Large Acceptance Spectrometer at Jefferson Laboratory. The kinematic range covered is 1.1 < W < 3 GeV and 1 < Q 2 < 6GeV 2. Results were obtained for about 6000 bins in W, Q 2, cos(θ*), and Φ*. Except at forward angles, very large target-spin asymmetries are observed over the entire W region. Reasonable agreement is found with phenomenological fits to previous datamore » for W < 1.6 GeV, but very large differences are seen at higher values of W. A generalized parton distributions (GPD)-based model is in poor agreement with the data. As a result, when combined with cross-sectional measurements, the present results provide powerful constraints on nucleon resonance amplitudes at moderate and large values of Q 2, for resonances with masses as high as 2.4 GeV.« less

Single and double spin asymmetries for deeply virtual Compton scattering measured with CLAS and a longitudinally polarized proton target

NASA Astrophysics Data System (ADS)

Pisano, S.; Biselli, A.; Niccolai, S.; Seder, E.; Guidal, M.; Mirazita, M.; Adhikari, K. P.; Adikaram, D.; Amaryan, M. J.; Anderson, M. D.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bosted, P.; Briscoe, B.; Brock, J.; Brooks, W. K.; Burkert, V. D.; Carlin, C.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crabb, D. G.; Crede, V.; D'Angelo, A.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Filippi, A.; Fleming, J. A.; Fradi, A.; Garillon, B.; Garçon, M.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hanretty, C.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jiang, X.; Jo, H. S.; Joo, K.; Joosten, S.; Keith, C. D.; Keller, D.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Kuhn, S. E.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacCormick, M.; MacGregor, I. J. D.; Mayer, M.; McKinnon, B.; Meekins, D. G.; Meyer, C. A.; Mokeev, V.; Montgomery, R. A.; Moody, C. I.; Munoz Camacho, C.; Nadel-Turonski, P.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Phelps, W.; Phillips, J. J.; Pogorelko, O.; Price, J. W.; Procureur, S.; Prok, Y.; Puckett, A. J. R.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Skorodumina, I.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strauch, S.; Sytnik, V.; Tian, Ye; Tkachenko, S.; Turisini, M.; Ungaro, M.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.; CLAS Collaboration

2015-03-01

Single-beam, single-target, and double spin asymmetries for hard exclusive electroproduction of a photon on the proton e →p →→e'p'γ are presented. The data were taken at Jefferson Lab using the CEBAF large acceptance spectrometer and a longitudinally polarized NH3 14 target. The three asymmetries were measured in 165 four-dimensional kinematic bins, covering the widest kinematic range ever explored simultaneously for beam and target-polarization observables in the valence quark region. The kinematic dependences of the obtained asymmetries are discussed and compared to the predictions of models of generalized parton distributions. The measurement of three DVCS spin observables at the same kinematic points allows a quasi-model-independent extraction of the imaginary parts of the H and H ˜ Compton form factors, which give insight into the electric and axial charge distributions of valence quarks in the proton.

Asymmetry of the Martian Current Sheet in a Multi-fluid MHD Model

NASA Astrophysics Data System (ADS)

Panoncillo, S. G.; Egan, H. L.; Dong, C.; Connerney, J. E. P.; Brain, D. A.; Jakosky, B. M.

2017-12-01

The solar wind carries interplanetary magnetic field (IMF) lines toward Mars, where they drape around the planet's conducting ionosphere, creating a current sheet behind the planet where the magnetic field has opposite polarity on either side. In its simplest form, the current sheet is often thought of as symmetric, extending behind the planet along the Mars-Sun line. Observations and model simulations, however, demonstrate that this idealized representation is only an approximation, and the actual scenario is much more complex. The current sheet can have 3D structure, move back and forth, and be situated dawnward or duskward of the Mars-Sun line. In this project, we utilized a library of global plasma model results for Mars consisting of a collection of multi-fluid MHD simulations where solar max/min, sub-solar longitude, and the orbital position of Mars are varied individually. The model includes Martian crustal fields, and was run for identical steady solar wind conditions. This library was created for the purpose of comparing model results to MAVEN data; we looked at the results of this model library to investigate current sheet asymmetries. By altering one variable at a time we were able to measure how these variables influence the location of the current sheet. We found that the current sheet is typically shifted toward the dusk side of the planet, and that modeled asymmetries are especially prevalent during solar min. Previous model studies that lack crustal fields have found that, for a Parker spiral IMF, the current sheet will shift dawnward, while our results typically show the opposite. This could expose certain limitations in the models used, or it could reveal an interaction between the solar wind and the plasma environment of Mars that has not yet been explored. MAVEN data may be compared to the model results to confirm the sense of the modeled asymmetry. These results help us to probe the physics controlling the Martian magnetotail and atmospheric

Target and double spin asymmetries of deeply virtual π0 production with a longitudinally polarized proton target and CLAS

NASA Astrophysics Data System (ADS)

Kim, A.; Avakian, H.; Burkert, V.; Joo, K.; Kim, W.; Adhikari, K. P.; Akbar, Z.; Anefalos Pereira, S.; Badui, R. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Bosted, P.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Djalali, C.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fersch, R.; Filippi, A.; Fleming, J. A.; Fradi, A.; Garc con, M.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hanretty, C.; Hattawy, M.; Heddle, D.; Hicks, K.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mattione, P.; McCracken, M. E.; McKinnon, B.; Mokeev, V.; Movsisyan, A.; Munevar, E.; Nadel-Turonski, P.; Net, L. A.; Niccolai, S.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Salgado, C.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Zachariou, N.; Zana, L.; Zhang, J.

2017-05-01

The target and double spin asymmetries of the exclusive pseudoscalar channel e → p → → epπ0 were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of Q2, xB, -t and ϕ. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs H˜T and ET, and complement previous measurements of unpolarized structure functions sensitive to the GPDs HT and EbarT. These data provide a crucial input for parametrizations of essentially unknown chiral-odd GPDs and will strongly influence existing theoretical calculations based on the handbag formalism.

Target and double spin asymmetries of deeply virtual π 0 production with a longitudinally polarized proton target and CLAS

DOE PAGES

Kim, A.; Avakian, H.; Burkert, V.; ...

2017-02-22

The target and double spin asymmetries of the exclusive pseudoscalar channelmore » $$\\vec e\\vec p\\to ep\\pi^0$$ were measured for the first time in the deep-inelastic regime using a longitudinally polarized 5.9 GeV electron beam and a longitudinally polarized proton target at Jefferson Lab with the CEBAF Large Acceptance Spectrometer (CLAS). The data were collected over a large kinematic phase space and divided into 110 four-dimensional bins of $Q^2$, $$x_B$$, $-t$ and $$\\phi$$. Large values of asymmetry moments clearly indicate a substantial contribution to the polarized structure functions from transverse virtual photon amplitudes. The interpretation of experimental data in terms of generalized parton distributions (GPDs) provides the first insight on the chiral-odd GPDs $$\\tilde{H}_T$$ and $$E_T$$, and complement previous measurements of unpolarized structure functions sensitive to the GPDs $$H_T$$ and $$\\bar E_T$$. Finally, these data provide necessary constraints for chiral-odd GPD parametrizations and will strongly influence existing theoretical handbag models.« less

Tensor Target Spin Asymmetries in Coherent π 0-Photoproduction on the Deuteron Including Intermediate η N N Interaction Within a Three-Body Approach

NASA Astrophysics Data System (ADS)

Darwish, Eed M.; Abou-Elsebaa, Hoda M.; Hassaneen, Khaled S. A.

2018-04-01

Motivated by the recent measurements from the VEPP-3 electron storage ring, we investigate the tensor target polarization asymmetries T 2 M ( M = 0, 1, 2) in the reaction γ d → π 0 d with a particular interest in the effect of the intermediate η N N three-body approach. This approach is based on realistic separable representations of the driving two-body interaction in the π N, η N, and NN subsystems. It is shown that the influence of rescattering effects in the intermediate state on the tensor target spin asymmetries is sizable at extreme backward pion angles. At forward angles, the contribution from the pure impulse approximation is dominated and the spin asymmetries show very little influence of rescattering effects. The sensitivity of results to the elementary pion photoproduction operator and to the NN potential model adopted for the deuteron wave function is investigated, and considerable dependences are found. The predicted spin asymmetries are also compared with available experimental data, and a satisfactory agreement with the recent data from VEPP-3 is obtained at photon energies below 400 MeV. At higher energies, the calculated spin asymmetries slightly underestimate the data.

Manual asymmetries in bimanual isochronous tapping tasks in children.

PubMed

Faria, Inês; Diniz, Ana; Barreiros, João

2017-01-01

Tapping tasks have been investigated throughout the years, with variations in features such as the complexity of the task, the use of one or both hands, the employ of auditory or visual stimuli, and the characteristics of the subjects. The evaluation of lateral asymmetries in tapping tasks in children offers an insight into the structure of rhythmic movements and handedness at early stages of development. The current study aims to investigate the ability of children (aged six and seven years-old) to maintain a rhythm, in a bimanual tapping task at two different target frequencies, as well as the manual asymmetries displayed while doing so. The analyzed data in this work are the series of the time intervals between successive taps. We suggest several profiles of behavior, regarding the overall performance of children in both tempo conditions. We also propose a new method of quantifying the variability of the performance and the asymmetry of the hands, based on ellipses placed on scatter plots of the non-dominant-dominant series versus the dominant-non-dominant series. We then use running correlations to identify changes of coordination tendencies over time. The main results show that variability is larger in the task with the longer target interval. Furthermore, most children evidence lateral asymmetries, but in general they show the capacity to maintain the mean of consecutive intertap intervals of both hands close to the target interval. Finally, we try to interpret our findings in the light of existing models and timing modes. Copyright © 2016 Elsevier B.V. All rights reserved.

Ratchet Transport of Chiral Particles Caused by the Transversal Asymmetry: Current Reversals and Particle Separation

NASA Astrophysics Data System (ADS)

Liu, Jian-li; Lu, Shi-cai; Ai, Bao-quan

2018-06-01

Due to the chirality of active particles, the transversal asymmetry can induce the the longitudinal directed transport. The transport of chiral active particles in a periodic channel is investigated in the presence of two types of the transversal asymmetry, the transverse force and the transverse rigid half-circle obstacles. For all cases, the counterclockwise and clockwise particles move to the opposite directions. For the case of the only transverse force, the chiral active particles can reverse their directions when increasing the transverse force. When the transverse rigid half-circle obstacles are introduced, the transport behavior of particles becomes more complex and multiple current reversals occur. The direction of the transport is determined by the competition between two types of the transversal asymmetry. For a given chirality, by suitably tailoring parameters, particles with different self-propulsion speed can move in different directions and can be separated.

Measurement of “pretzelosity” asymmetry of charged pion production in semi-inclusive deep inelastic scattering on a polarized He 3 target

DOE PAGES

Zhang, Y.; Qian, X.; Allada, K.; ...

2014-11-24

An experiment to measure single-spin asymmetries in semi-inclusive production of charged pions in deep-inelastic scattering on a transversely polarized ³He target was performed at Jefferson Lab in the kinematic region of 0.16 < x < 0.35 and 1.4 < Q² < 2.7 GeV². Our results show that both π ± on 3He and on neutron pretzelosity asymmetries are consistent with zero within experimental uncertainties.

Single-Transverse-Spin-Asymmetry studies with a fixed-target experiment using the LHC beams (AFTER@LHC)

DOE PAGES

Lansberg, J. P.; Anselmino, M.; Arnaldi, R.; ...

2016-11-19

Here we discuss the potential of AFTER@LHC to measure single-transverse-spin asymmetries in open-charm and bottomonium production. With a HERMES-like hydrogen polarised target, such measurements over a year can reach precisions close to the per cent level. This is particularly remarkable since these analyses can probably not be carried out anywhere else.

Visual search asymmetries within color-coded and intensity-coded displays.

PubMed

Yamani, Yusuke; McCarley, Jason S

2010-06-01

Color and intensity coding provide perceptual cues to segregate categories of objects within a visual display, allowing operators to search more efficiently for needed information. Even within a perceptually distinct subset of display elements, however, it may often be useful to prioritize items representing urgent or task-critical information. The design of symbology to produce search asymmetries (Treisman & Souther, 1985) offers a potential technique for doing this, but it is not obvious from existing models of search that an asymmetry observed in the absence of extraneous visual stimuli will persist within a complex color- or intensity-coded display. To address this issue, in the current study we measured the strength of a visual search asymmetry within displays containing color- or intensity-coded extraneous items. The asymmetry persisted strongly in the presence of extraneous items that were drawn in a different color (Experiment 1) or a lower contrast (Experiment 2) than the search-relevant items, with the targets favored by the search asymmetry producing highly efficient search. The asymmetry was attenuated but not eliminated when extraneous items were drawn in a higher contrast than search-relevant items (Experiment 3). Results imply that the coding of symbology to exploit visual search asymmetries can facilitate visual search for high-priority items even within color- or intensity-coded displays. PsycINFO Database Record (c) 2010 APA, all rights reserved.

Assessment of tidal circulation and tidal current asymmetry in the Iroise sea with specific emphasis on characterization of tidal energy resources around the Ushant Island.

NASA Astrophysics Data System (ADS)

Thiébaut, Maxime; Sentchev, Alexei

2015-04-01

We use the current velocity time series recorded by High Frequency Radars (HFR) to study circulation in highly energetic tidal basin - the Iroise sea. We focus on the analysis of tidal current pattern around the Ushant Island which is a promising site of tidal energy. The analysis reveals surface current speeds reaching 4 m/s in the North of Ushant Island and in the Fromveur Strait. In these regions 1 m/s is exceeded 60% of time and up to 70% of time in center of Fromveur. This velocity value is particularly interesting because it represents the cut-in-speed of the most of marine turbine devices. Tidal current asymmetry is not always considered in tidal energy site selection. However, this quantity plays an important role in the quantification of hydrokinetic resources. Current velocity times series recorded by HFR highlights the existence of a pronounced asymmetry in current magnitude between the flood and ebb tide ranging from -0.5 to more 2.5. Power output of free-stream devices depends to velocity cubed. Thus a small current asymmetry can generate a significant power output asymmetry. Spatial distribution of asymmetry coefficient shows persistent pattern and fine scale structure which were quantified with high degree of accuracy. The particular asymmetry evolution on both side of Fromveur strait is related to the spatial distribution of the phase lag of the principal semi-diurnal tidal constituent M2 and its higher order harmonics. In Fromveur, the asymmetry is reinforced due to the high velocity magnitude of the sixth-diurnal tidal harmonics. HF radar provides surface velocity speed, however the quantification of hydrokinetic resources has to take into account the decreasing of velocity with depth. In order to highlight this phenomenon, we plot several velocity profiles given by an ADCP which was installed in the HFR study area during the same period. The mean velocity in the water column calculated by using the ADCP data show that it is about 80% of the

Beam-target double-spin asymmetry in quasielastic electron scattering off the deuteron with CLAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayer, M.; Kuhn, S. E.; Adhikari, K. P.

Background: The deuteron plays a pivotal role in nuclear and hadronic physics, as both the simplest bound multi-nucleon system and as an ``effective neutron target''. Quasi-elastic electron scattering on the deuteron is a benchmark reaction to test our understanding of deuteron structure and the properties and interactions of the two nucleons bound in the deuteron. Purpose: The experimental data presented here test state-of-the-art models of the deuteron and the two-nucleon interaction in the final state after two-body breakup of the deuteron. Focusing on polarization degrees of freedom, we gain information on the limits of the Impulse Approximation (IA) picture andmore » put the interpretation of spin structure measurements with deuterium on a firmer footing. Information on this reaction can also be used to improve the determination of the deuteron polarization through quasi-elastic electron scattering. Method: We measured the beam-target double spin asymmetry (A||) for quasi-elastic electron scattering off the deuteron at several beam energies (1.6-1.7 GeV, 2.5 GeV, 4.2 GeV and 5.6-5.8 GeV), using the CEBAF Large Acceptance Spectrometer (CLAS) at Thomas Jefferson National Accelerator Facility. The deuterons were polarized along (or opposite to) the beam direction. The double spin asymmetries were measured as a function of photon virtuality Q2 (0.13-3.17 (GeV/c)2), missing momentum (pm = 0.0 - 0.5 GeV/c), and the angle between the (inferred) ``spectator'' neutron and the momentum transfer direction (θnq). Results: The results are compared with a recent model that includes Final State Interactions (FSI) using a complete parameterization of nucleon-nucleon scattering, as well as a simplified model using the Plane Wave Impulse Approximation (PWIA). We find overall good agreement with both the PWIA and FSI expectations at low to medium missing momenta (pm ≤ 0.25 GeV/c), including the change of the asymmetry due to the contribution of the deuteron D-state at

Beam-target double-spin asymmetry in quasielastic electron scattering off the deuteron with CLAS

NASA Astrophysics Data System (ADS)

Mayer, M.; Kuhn, S. E.; Adhikari, K. P.; Akbar, Z.; Anefalos Pereira, S.; Asryan, G.; Avakian, H.; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Boiarinov, S.; Bosted, P.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Fersch, R.; Filippi, A.; Fleming, J. A.; Forest, T. A.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hakobyan, H.; Hanretty, C.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Keith, C.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Kubarovsky, V.; Lanza, L.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; McKinnon, B.; Meekins, D.; Mirazita, M.; Mokeev, V.; Movsisyan, A.; Net, L. A.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pogorelko, O.; Price, J. W.; Prok, Y.; Puckett, A. J. R.; Ripani, M.; Rizzo, A.; Rosner, G.; Rossi, P.; Sabatié, F.; Schumacher, R. A.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Stepanyan, S.; Strauch, S.; Sytnik, V.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zhang, J.; Zonta, I.; CLAS Collaboration

2017-02-01

Background: The deuteron plays a pivotal role in nuclear and hadronic physics, as both the simplest bound multinucleon system and as an effective neutron target. Quasielastic electron scattering on the deuteron is a benchmark reaction to test our understanding of deuteron structure and the properties and interactions of the two nucleons bound in the deuteron. Purpose: The experimental data presented here can be used to test state-of-the-art models of the deuteron and the two-nucleon interaction in the final state after two-body breakup of the deuteron. Focusing on polarization degrees of freedom, we gain information on spin-momentum correlations in the deuteron ground state (due to the D -state admixture) and on the limits of the impulse approximation (IA) picture as it applies to measurements of spin-dependent observables like spin structure functions for bound nucleons. Information on this reaction can also be used to reduce systematic uncertainties on the determination of neutron form factors or deuteron polarization through quasielastic polarized electron scattering. Method: We measured the beam-target double-spin asymmetry (A||) for quasielastic electron scattering off the deuteron at several beam energies (1.6 -1.7 , 2.5, 4.2, and 5.6 -5.8 GeV ), using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The deuterons were polarized along (or opposite to) the beam direction. The double-spin asymmetries were measured as a function of photon virtuality Q2(0.13 -3.17 (GeV/c ) 2) , missing momentum (pm=0.0 -0.5 GeV /c ), and the angle between the (inferred) spectator neutron and the momentum transfer direction (θn q). Results: The results are compared with a recent model that includes final-state interactions (FSI) using a complete parametrization of nucleon-nucleon scattering, as well as a simplified model using the plane wave impulse approximation (PWIA). We find overall good agreement with both the PWIA and FSI

Quantifying Hemispheric Asymmetry of Auroral Currents by Polar Region Interhemispheric Magnetic Observatories (PRIMO)

NASA Astrophysics Data System (ADS)

Chi, P. J.; Russell, C. T.; Strangeway, R. J.; Connors, M. G.; Wilson, T. J.; Angelopoulos, V.; Anderson, B. J.; Kadokura, A.

2016-12-01

Previous observations have demonstrated that substorm auroras and the associated electric currents can exhibit substantial north-south asymmetry. Possible mechanisms that cause this asymmetry include the penetration of IMF By into the magnetotail, the difference in ionospheric conductivity due to the dipole tilt angle, and the difference in solar wind dynamo efficiency due to IMF Bx combined with the tilt angle. The relative importance of these factors, however, has not been determined, due to paucity of observations in the southern hemisphere. To resolve this difficulty, we propose to establish three new stations in West Antarctica for measuring geomagnetic perturbations. The three magnetometer stations are located at Lepley Lunatak, Union Glacier, and Whitmore Mountains, between -2° W and 7° W magnetic longitude at L-values 4, 6, and 8. These locations are magnetically conjugate to the recently established AUTUMNX magnetometers along the eastern shore of the Hudson Bay, enabling unique conjugate observations by two magnetometer chains at auroral latitudes and subauroral latitudes when close to midnight. These conjugate magnetic field observations, with concurrent satellite measurements by the AMPERE constellation and the Heliophysics System Observatory, can differentiate between magnetospheric and ionospheric contributions in the hemispheric asymmetry. The comparison with the conjugate observations at the Syowa and Iceland stations can shed light on the longitudinal extent of the hemispheric asymmetry. The PRIMO fluxgate magnetometer system includes a dedicated power and data communications platform developed by UNAVCO and successfully operated at ANET stations in the same region. The three PRIMO systems are co-located with existing ANET stations, facilitating logistic efficiencies such as transportation, cross-trained personnel, and common components. Our plan follows recommendations by the latest Heliophysics Decadal Study for ground-based observations

Beam-target double-spin asymmetry in quasielastic electron scattering off the deuteron with CLAS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mayer, M.; Kuhn, S. E.; Adhikari, K. P.

The deuteron plays a pivotal role in nuclear and hadronic physics, as both the simplest bound multinucleon system and as an effective neutron target. Quasielastic electron scattering on the deuteron is a benchmark reaction to test our understanding of deuteron structure and the properties and interactions of the two nucleons bound in the deuteron. The experimental data presented here can be used to test state-of-the-art models of the deuteron and the two-nucleon interaction in the final state after two-body breakup of the deuteron. Focusing on polarization degrees of freedom, we gain information on spin-momentum correlations in the deuteron ground statemore » (due to the D-state admixture) and on the limits of the impulse approximation (IA) picture as it applies to measurements of spin-dependent observables like spin structure functions for bound nucleons. Information on this reaction can also be used to reduce systematic uncertainties on the determination of neutron form factors or deuteron polarization through quasielastic polarized electron scattering. Furthermore, we measured the beam-target double-spin asymmetry (A ||) for quasielastic electron scattering off the deuteron at several beam energies (1.6–1.7, 2.5, 4.2, and 5.6–5.8GeV), using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The deuterons were polarized along (or opposite to) the beam direction. The double-spin asymmetries were measured as a function of photon virtuality Q 2 (0.13–3.17(GeV/c) 2), missing momentum (p m=0.0–0.5GeV/c), and the angle between the (inferred) spectator neutron and the momentum transfer direction (θ nq). We compare our results with a recent model that includes final-state interactions (FSI) using a complete parametrization of nucleon-nucleon scattering, as well as a simplified model using the plane wave impulse approximation (PWIA). We find overall good agreement with both the PWIA and FSI expectations at low

Beam-target double-spin asymmetry in quasielastic electron scattering off the deuteron with CLAS

DOE PAGES

Mayer, M.; Kuhn, S. E.; Adhikari, K. P.; ...

2017-02-24

The deuteron plays a pivotal role in nuclear and hadronic physics, as both the simplest bound multinucleon system and as an effective neutron target. Quasielastic electron scattering on the deuteron is a benchmark reaction to test our understanding of deuteron structure and the properties and interactions of the two nucleons bound in the deuteron. The experimental data presented here can be used to test state-of-the-art models of the deuteron and the two-nucleon interaction in the final state after two-body breakup of the deuteron. Focusing on polarization degrees of freedom, we gain information on spin-momentum correlations in the deuteron ground statemore » (due to the D-state admixture) and on the limits of the impulse approximation (IA) picture as it applies to measurements of spin-dependent observables like spin structure functions for bound nucleons. Information on this reaction can also be used to reduce systematic uncertainties on the determination of neutron form factors or deuteron polarization through quasielastic polarized electron scattering. Furthermore, we measured the beam-target double-spin asymmetry (A ||) for quasielastic electron scattering off the deuteron at several beam energies (1.6–1.7, 2.5, 4.2, and 5.6–5.8GeV), using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. The deuterons were polarized along (or opposite to) the beam direction. The double-spin asymmetries were measured as a function of photon virtuality Q 2 (0.13–3.17(GeV/c) 2), missing momentum (p m=0.0–0.5GeV/c), and the angle between the (inferred) spectator neutron and the momentum transfer direction (θ nq). We compare our results with a recent model that includes final-state interactions (FSI) using a complete parametrization of nucleon-nucleon scattering, as well as a simplified model using the plane wave impulse approximation (PWIA). We find overall good agreement with both the PWIA and FSI expectations at low

Formation of Dawn-Dusk Asymmetry in Earth's Magnetotail Thin Current Sheet: A Three-Dimensional Particle-In-Cell Simulation

NASA Astrophysics Data System (ADS)

Lu, San; Pritchett, P. L.; Angelopoulos, V.; Artemyev, A. V.

2018-04-01

Using a three-dimensional particle-in-cell simulation, we investigate the formation of dawn-dusk asymmetry in Earth's magnetotail. The magnetotail current sheet is compressed by an external driving electric field down to a thickness on the order of ion kinetic scales. In the resultant thin current sheet (TCS) where the magnetic field line curvature radius is much smaller than ion gyroradius, a significant portion of the ions becomes unmagnetized and decoupled from the magnetized electrons, giving rise to a Hall electric field Ez and an additional cross-tail current jy caused by the unmagnetized ions being unable to comove with the electrons in the Hall electric field. The Hall electric field transports via E × B drift magnetic flux and magnetized plasma dawnward, causing a reduction of the current sheet thickness and the normal magnetic field Bz on the duskside. This leads to an even stronger Hall effect (stronger jy and Ez) in the duskside TCS. Thus, due to the internal kinetic effects in the TCS, namely, the Hall effect and the associated dawnward E × B drift, the magnetotail dawn-dusk asymmetry forms in a short time without any global, long-term effects. The duskside preference of reconnection and associated dynamic phenomena (such as substorm onsets, dipolarizing flux bundles, fast flows, energetic particle injections, and flux ropes), which has been pervasively observed by spacecraft in the past 20 years, can thus be explained as a consequence of this TCS asymmetry.

Effects of azimuth-symmetric acceptance cutoffs on the measured asymmetry in unpolarized Drell-Yan fixed-target experiments

NASA Astrophysics Data System (ADS)

Bianconi, A.; Bussa, M. P.; Destefanis, M.; Ferrero, L.; Greco, M.; Maggiora, M.; Spataro, S.

2013-04-01

Fixed-target unpolarized Drell-Yan experiments often feature an acceptance depending on the polar angle of the lepton tracks in the laboratory frame. Typically leptons are detected in a defined angular range, with a dead zone in the forward region. If the cutoffs imposed by the angular acceptance are independent of the azimuth, at first sight they do not appear dangerous for a measurement of the cos(2 φ) asymmetry, which is relevant because of its association with the violation of the Lam-Tung rule and with the Boer-Mulders function. On the contrary, direct simulations show that up to 10 percent asymmetries are produced by these cutoffs. These artificial asymmetries present qualitative features that allow them to mimic the physical ones. They introduce some model dependence in the measurements of the cos(2 φ) asymmetry, since a precise reconstruction of the acceptance in the Collins-Soper frame requires a Monte Carlo simulation, that in turn requires some detailed physical input to generate event distributions. Although experiments in the eighties seem to have been aware of this problem, the possibility of using the Boer-Mulders function as an input parameter in the extraction of transversity has much increased the requirements of precision on this measurement. Our simulations show that the safest approach to these measurements is a strong cutoff on the Collins-Soper polar angle. This reduces statistics, but does not necessarily decrease the precision in a measurement of the Boer-Mulders function.

Probing noncommutativities of phase space by using persistent charged current and its asymmetry

NASA Astrophysics Data System (ADS)

Ma, Kai; Ren, Ya-Jie; Wang, Ya-Hui

2018-06-01

Nontrivial algebra structures of the coordinate and momentum operators are potentially important for describing possible new physics. The persistent charged current in a metal ring is expected to be sensitive to the nontrivial dynamics due to noncommutativities of phase space. In this paper, we propose a new asymmetric observable for probing the noncommutativity of momentum operators. We also analyzed the temperature dependence of this observable, and we find that the asymmetry holds at a finite temperature. The critical temperature, above which the correction due to coordinate noncommutativity is negligible, is also derived.

Measurement of parity-violating asymmetry in electron-deuteron inelastic scattering

DOE PAGES

Wang, D.; Pan, K.; Subedi, R.; ...

2015-04-01

The parity-violating asymmetries between a longitudinally-polarized electron beam and an unpolarized deuterium target have been measured recently. The measurement covered two kinematic points in the deep inelastic scattering region and five in the nucleon resonance region. We provide here details of the experimental setup, data analysis, and results on all asymmetry measurements including parity-violating electron asymmetries and those of inclusive pion production and beam-normal asymmetries. The parity-violating deep-inelastic asymmetries were used to extract the electron-quark weak effective couplings, and the resonance asymmetries provided the first evidence for quark-hadron duality in electroweak observables. These electron asymmetries and their interpretation were publishedmore » earlier, but are presented here in more detail.« less

Measurement of an asymmetry parameter in the decay of the cascade-minus hyperon

NASA Astrophysics Data System (ADS)

Chakravorty, Alak

2000-10-01

Fermilab experiment E756 collected a large dataset of polarized Ξ -hyperon decays, produced by 800-GeV/c unpolarized protons on a beryllium target. Of principal interest was the decay process Ξ - --> Λ0π- --> pπ-π-. An analysis of the asymmetry parameters of this decay was carried out on a sample of 1.3 × 106 Ξ- decays. φ Ξ was measured to be -1.33° +/- 2.66° +/- 1.22°, where the first error is statistical and the second is systematic. This corresponds to a measurement of the asymmetry parameter βΞ = -0.021 +/- 0.042 +/- 0.019, which is consistent with current theoretical estimates.

Charging-induced asymmetry in molecular conductors

NASA Astrophysics Data System (ADS)

Zahid, F.; Ghosh, A. W.; Paulsson, M.; Polizzi, E.; Datta, S.

2004-12-01

We investigate the origin of asymmetry in various measured current-voltage (I-V) characteristics of molecules with no inherent spatial asymmetry, with particular focus on a recent break junction measurement. We argue that such asymmetry arises due to unequal coupling with the contacts and a consequent difference in charging effects, which can only be captured in a self-consistent model for molecular conduction. The direction of the asymmetry depends on the sign of the majority carriers in the molecule. For conduction through highest occupied molecular orbitals (i.e., HOMO or p -type conduction), the current is smaller for positive voltage on the stronger contact, while for conduction through lowest unoccupied molecular orbitals (i.e., LUMO or n -type conduction), the sense of the asymmetry is reversed. Within an extended Hückel description of the molecular chemistry and the contact microstructure (with two adjustable parameters, the position of the Fermi energy and the sulphur-gold bond length), an appropriate description of Poisson’s equation, and a self-consistently coupled nonequilibrium Green’s function description of transport, we achieve good agreement between theoretical and experimental I-V characteristics, both in shape as well as overall magnitude.

Beam-Helicity Asymmetries in Double-Charged-Pion Photoproduction on the Proton

NASA Astrophysics Data System (ADS)

Strauch, S.; Berman, B. L.; Adams, G.; Ambrozewicz, P.; Anghinolfi, M.; Asavapibhop, B.; Asryan, G.; Audit, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Batourine, V.; Battaglieri, M.; Beard, K.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Bennhold, C.; Biselli, A. S.; Boiarinov, S.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Carnahan, B.; Chen, S.; Cole, P. L.; Coleman, A.; Coltharp, P.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J. P.; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; de Sanctis, E.; Deur, A.; Devita, R.; Dharmawardane, K. V.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Fatemi, R.; Fedotov, G.; Feldman, G.; Feuerbach, R. J.; Fix, A.; Forest, T. A.; Funsten, H.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hu, J.; Huertas, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Joo, K.; Juengst, H. G.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Lee, T.; Lima, A. C. S.; Livingston, K.; Lukashin, K.; Manak, J. J.; Marchand, C.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morrow, S. A.; Muccifora, V.; Mueller, J.; Mutchler, G. S.; Nadel-Turonski, P.; Napolitano, J.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Philips, S. A.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Roberts, W.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Shafi, A.; Sharabian, Y. G.; Shaw, J.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Suleiman, R.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zana, L.; Zhang, J.

2005-10-01

Beam-helicity asymmetries for the two-pion-photoproduction reaction γ→p→pπ+π- have been studied for the first time in the resonance region for center-of-mass energies between 1.35 and 2.30 GeV. The experiment was performed at Jefferson Lab with the CEBAF Large Acceptance Spectrometer using circularly polarized tagged photons incident on an unpolarized hydrogen target. Beam-helicity-dependent angular distributions of the final-state particles were measured. The large cross-section asymmetries exhibit strong sensitivity to the kinematics and dynamics of the reaction. The data are compared with the results of various phenomenological model calculations, and show that these models currently do not provide an adequate description for the behavior of this new observable.

Measurement of target and double-spin asymmetries for the e ⃗p ⃗→e π+(n ) reaction in the nucleon resonance region at low Q2

NASA Astrophysics Data System (ADS)

Zheng, X.; Adhikari, K. P.; Bosted, P.; Deur, A.; Drozdov, V.; El Fassi, L.; Kang, Hyekoo; Kovacs, K.; Kuhn, S.; Long, E.; Phillips, S. K.; Ripani, M.; Slifer, K.; Smith, L. C.; Adikaram, D.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Asryan, G.; Avakian, H.; Badui, R. A.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chen, J.-P.; Chetry, T.; Choi, Seonho; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Djalali, C.; Dodge, G. E.; Dupre, R.; Egiyan, H.; El Alaoui, A.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Fersch, R.; Filippi, A.; Fleming, J. A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gleason, C.; Golovach, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hanretty, C.; Harrison, N.; Hattawy, M.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jiang, H.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Lanza, L.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Mirazita, M.; Mokeev, V.; Movsisyan, A.; Munevar, E.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Net, L. A.; Ni, A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Peng, P.; Pisano, S.; Pogorelko, O.; Price, J. W.; Puckett, A. J. R.; Raue, B. A.; Rizzo, A.; Rosner, G.; Rossi, P.; Roy, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zhang, J.; Zonta, I.; CLAS Collaboration

2016-10-01

We report measurements of target- and double-spin asymmetries for the exclusive channel e ⃗p ⃗→e π+(n ) in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH3 target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low Q2 range from 0.0065 to 0.35 (GeV/c ) 2 . The Q2 access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as 6∘. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID, and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.

Measurement of target and double-spin asymmetries for the e → p → → e π + ( n ) reaction in the nucleon resonance region at low Q 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, X.; Adhikari, K. P.; Bosted, P.

We repormore » t measurements of target- and double-spin asymmetries for the exclusive channel e → p → → e π + ( n ) in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH3 target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3, and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low Q 2 range from 0.0065 to 0.35 (GeV/c) 2. The Q 2 access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as 6 degrees. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID, and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.« less

Measurement of target and double-spin asymmetries for the $$\\vec e\\vec p\\to e\\pi^+ (n)$$ reaction in the nucleon resonance region at low $Q^2$

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng, X.; Adhikari, K. P.; Bosted, P.

We report measurements of target- and double-spin asymmetries for the exclusive channelmore » $$\\vec e\\vec p\\to e\\pi^+ (n)$$ in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH$$_3$$ target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3 and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low $Q^2$ range from $0.0065$ to $0.35$ (GeV$/c$)$^2$. The $Q^2$ access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as $$6^\\circ$$. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.« less

Measurement of target and double-spin asymmetries for the $$\\vec e\\vec p\\to e\\pi^+ (n)$$ reaction in the nucleon resonance region at low $Q^2$

DOE PAGES

Zheng, X.; Adhikari, K. P.; Bosted, P.; ...

2016-10-19

We report measurements of target- and double-spin asymmetries for the exclusive channelmore » $$\\vec e\\vec p\\to e\\pi^+ (n)$$ in the nucleon resonance region at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). These asymmetries were extracted from data obtained using a longitudinally polarized NH$$_3$$ target and a longitudinally polarized electron beam with energies 1.1, 1.3, 2.0, 2.3 and 3.0 GeV. The new results are consistent with previous CLAS publications but are extended to a low $Q^2$ range from $0.0065$ to $0.35$ (GeV$/c$)$^2$. The $Q^2$ access was made possible by a custom-built Cherenkov detector that allowed the detection of electrons for scattering angles as low as $$6^\\circ$$. These results are compared with the unitary isobar models JANR and MAID, the partial-wave analysis prediction from SAID and the dynamic model DMT. In many kinematic regions our results, in particular results on the target asymmetry, help to constrain the polarization-dependent components of these models.« less

Target and double spin asymmetries for {rvec e} {rvec p} {yields} e{prime} p {pi}{sup 0}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Angela Biselli

2004-03-01

An extensive experimental program to measure the spin structure of the nucleons is carried out in Hall B with the CLAS detector at Jefferson Lab using a polarized electron beam incident on a polarized target. Spin degrees of freedom offer the possibility to test, in an independent way, existing models of resonance electroproduction. The present analysis selects the exclusive channel {rvec p}({rvec e}, e{prime}, p){pi}{sup 0} from data taken in 2000-2001, to extract single and double asymmetries in a Q{sup 2} range from 0.2 to 0.75 GeV{sup 2} and W range from 1.1 to 1.6 GeV/c{sup 2}. Results of themore » asymmetries will be presented as a function of the center of mass decay angles of the {pi}{sup 0} and compared with the unitary isobar model MAID, the dynamic model by Sato and Lee and the dynamic model DMT.« less

The North-South Asymmetry of the Heliospheric Current Sheet: Results of an MHD Simulation

NASA Technical Reports Server (NTRS)

Usmanov, Arcadi V.; Goldstein, Melvyn L.

2013-01-01

A displacement of the heliospheric current sheet (HCS) south of the helioequator by approx.10deg was proposed by Simpson et al. (1996) as a possible explanation of the north-south asymmetry in the galactic cosmic rays observed by Ulysses during its first fast transit in 1994-1995. The idea was not supported by magnetic field measurements on Ulysses and, on this ground, was dismissed by Simpson et al. (1996). In addition, Erdos & Balogh (1998) argued that any north-south symmetry was unlikely as there should be flux balance between the magnetic sectors of opposite polarity. Nonetheless, many in the scientific community have accepted the original suggestion of Simpson et al. (1996) that a displacement of the HCS was responsible for the cosmic ray asymmetry. In this paper, using a magnetohydrodynamic model of the solar corona and solar wind that includes both dipole and quadrupole magnetic source terms, we show that a north-south asymmetry of the magnetic field on the Sun does not give rise to a displacement of the HCS. The lack of displacement of the HCS results from a latitudinal redistribution of magnetic flux near the Sun where the plasma beta much < 1. The latitudinal redistribution is a direct consequence of the magnetic field gradient between pole and equator. Near the Sun, the latitudinal gradient in magnetic field generates meridional flows directed equatorward that tend to relax the gradient in the magnetic field (to make it more latitude-independent) as heliocentric distance increases. If there is an asymmetry between north and south magnetic field strength then the meridional flows are also asymmetric (i.e., stronger in the hemisphere of stronger magnetic field). Because the magnetic fluxes (positive and negative) in the hemispheres must be equal, the redistribution shifts the HCS into balance by approx. 16 R(solar mass). At larger distances, where the magnetic field is relatively weak (beta much > 1), the HCS can be displaced if there is a difference in

Beam-target helicity asymmetry for γ → n → → π - p in the N * resonance region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, D.; Peng, P.; Bass, C.

In this paper, we report the first beam-target double-polarization asymmetries in themore » $$\\gamma + n(p) \\rightarrow \\pi^- + p(p)$$ reaction spanning the nucleon resonance region from invariant mass $W$= $1500$ to $2300$ MeV. Circularly polarized photons and longitudinally polarized deuterons in $HD$ have been used with the CLAS detector at Jefferson Lab. The exclusive final state has been extracted using three very different analysis techniques that show excellent agreement, and these have been used to deduce the $E$ polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses, and have led to revised values for several $$\\gamma nN^*$$ resonance photo-couplings.« less

Beam-target helicity asymmetry for γ → n → → π - p in the N * resonance region

DOE PAGES

Ho, D.; Peng, P.; Bass, C.; ...

2017-06-16

In this paper, we report the first beam-target double-polarization asymmetries in themore » $$\\gamma + n(p) \\rightarrow \\pi^- + p(p)$$ reaction spanning the nucleon resonance region from invariant mass $W$= $1500$ to $2300$ MeV. Circularly polarized photons and longitudinally polarized deuterons in $HD$ have been used with the CLAS detector at Jefferson Lab. The exclusive final state has been extracted using three very different analysis techniques that show excellent agreement, and these have been used to deduce the $E$ polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses, and have led to revised values for several $$\\gamma nN^*$$ resonance photo-couplings.« less

Beam-Target Helicity Asymmetry for γ → n → → π - p in the N * Resonance Region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ho, D.; Peng, P.; Bass, C.

2017-06-01

We report the first beam-target double-polarization asymmetries in the gamma+n(p)->pi(-)+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several gamma nN*more » resonance photocouplings.« less

Figure-ground asymmetries in the Implicit Association Test (IAT).

PubMed

Rothermund, K; Wentura, D

2001-01-01

Based on the assumption that binary classification tasks are often processed asymmetrically (figure-ground asymmetries), two experiments showed that association alone cannot account for effects observed in the Implicit Association Test (IAT). Experiment 1 (N = 16) replicated a standard version of the IAT effect using old vs. young names as target categories and good and bad words as attribute categories. However, reliable compatibility effects were also found for a modified version of the task in which neutral words vs. nonwords instead of good vs. bad words were used as attribute categories. In Experiment 2 (N = 8), a reversed IAT effect was observed after the figure-ground asymmetry in the target dimension had been inverted by a previous go/nogo detection task in which participants searched for exemplars of the category "young." The experiments support the hypothesis that figure-ground asymmetries produce compatibility effects in the IAT and suggest that IAT effects do not rely exclusively on evaluative associations between the target and attribute categories.

First measurement of target and double spin asymmetries for e→p→→epπ0 in the nucleon resonance region above the Δ(1232)

NASA Astrophysics Data System (ADS)

Biselli, A. S.; Burkert, V. D.; Amaryan, M. J.; Asryan, G.; Avakian, H.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Battaglieri, M.; Bedlinskiy, I.; Bellis, M.; Benmouna, N.; Berman, B. L.; Blaszczyk, L.; Bookwalter, C.; Boiarinov, S.; Bosted, P.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Casey, L.; Chen, S.; Cheng, L.; Cole, P. L.; Collins, P.; Coltharp, P.; Crabb, D.; Crede, V.; Dale, D.; Dashyan, N.; de Masi, R.; de Vita, R.; de Sanctis, E.; Degtyarenko, P. V.; Deur, A.; Dhamija, S.; Dickson, R.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dugger, M.; Dzyubak, O. P.; Egiyan, H.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Feuerbach, R.; Fersch, R.; Forest, T. A.; Fradi, A.; Garçon, M.; Gavaliann, G.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Gothe, R. W.; Graham, L.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Hassall, N.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Johnstone, J. R.; Joo, K.; Juengst, H. G.; Kalantarians, N.; Keller, D.; Kellie, J. D.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Kossov, M.; Krahn, Z.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Kuznetsov, V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Livingston, K.; Lu, H. Y.; MacCormick, M.; Markov, N.; Mattione, P.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Mirazita, M.; Mokeev, V.; Moreno, B.; Moriya, K.; Morrow, S. A.; Moteabbed, M.; Munevar, E.; Mutchler, G. S.; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Park, S.; Pasyuk, E.; Paterson, C.; Pereira, S. Anefalos; Pierce, J.; Pivnyuk, N.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salamanca, J.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schott, D.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Sharov, D.; Shvedunov, N. V.; Smith, E. S.; Sober, D. I.; Sokhan, D.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tedeschi, D. J.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yurov, M.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.

2008-10-01

The exclusive channel p→(e→,e'p)π0 was studied in the first and second nucleon resonance regions in the Q2 range from 0.187 to 0.770GeV2 at Jefferson Lab using the CEBAF Large Acceptance Spectrometer. Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the π0 and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data set, once included in the global fits of the above models, is expected to place strong constraints on the electrocoupling amplitudes A1/2 and S1/2 for the Roper resonance N(1400)P11 and the N(1535)S11 and N(1520)D13 states.

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

NASA Astrophysics Data System (ADS)

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

2017-10-01

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

Attentional sensitivity and asymmetries of vertical saccade generation in monkey

NASA Technical Reports Server (NTRS)

Zhou, Wu; King, W. M.; Shelhamer, M. J. (Principal Investigator)

2002-01-01

The first goal of this study was to systematically document asymmetries in vertical saccade generation. We found that visually guided upward saccades have not only shorter latencies, but higher peak velocities, shorter durations and smaller errors. The second goal was to identify possible mechanisms underlying the asymmetry in vertical saccade latencies. Based on a recent model of saccade generation, three stages of saccade generation were investigated using specific behavioral paradigms: attention shift to a visual target (CUED paradigm), initiation of saccade generation (GAP paradigm) and release of the motor command to execute the saccade (DELAY paradigm). Our results suggest that initiation of a saccade (or "ocular disengagement") and its motor release contribute little to the asymmetry in vertical saccade latency. However, analysis of saccades made in the CUED paradigm indicated that it took less time to shift attention to a target in the upper visual field than to a target in the lower visual field. These data suggest that higher attentional sensitivity to targets in the upper visual field may contribute to shorter latencies of upward saccades.

Asymmetry in search.

PubMed

Kaindl, H; Kainz, G; Radda, K

2001-01-01

Most of the work on search in artificial intelligence (AI) deals with one search direction only-mostly forward search-although it is known that a structural asymmetry of the search graph causes differences in the efficiency of searching in the forward or the backward direction, respectively. In the case of symmetrical graph structure, however, current theory would not predict such differences in efficiency. In several classes of job sequencing problems, we observed a phenomenon of asymmetry in search that relates to the distribution of the are costs in the search graph. This phenomenon can be utilized for improving the search efficiency by a new algorithm that automatically selects the search direction. We demonstrate fur a class of job sequencing problems that, through the utilization of this phenomenon, much more difficult problems can be solved-according to our best knowledge-than by the best published approach, and on the same problems, the running time is much reduced. As a consequence, we propose to check given problems for asymmetrical distribution of are costs that may cause asymmetry in search.

Relationship Between Muscle Strength Asymmetry and Body Sway in Older Adults.

PubMed

Koda, Hitoshi; Kai, Yoshihiro; Murata, Shin; Osugi, Hironori; Anami, Kunihiko; Fukumoto, Takahiko; Imagita, Hidetaka

2018-05-31

The purpose of this study was to investigate the relationship between muscle strength asymmetry and body sway while walking. We studied 63 older adult women. Strong side and weak side of knee extension strength, toe grip strength, hand grip strength, and body sway while walking were measured. The relationship between muscle strength asymmetry for each muscle and body sway while walking was evaluated using Pearson's correlation coefficient. Regarding the muscles recognized to have significant correlation with body sway, the asymmetry cutoff value causing an increased sway was calculated. Toe grip strength asymmetry was significantly correlated with body sway. Toe grip strength asymmetry causing an increased body sway had a cutoff value of 23.5%. Our findings suggest toe grip strength asymmetry may be a target for improving gait stability.

Tidal asymmetry in a funnel-shaped estuary with mixed semidiurnal tides

NASA Astrophysics Data System (ADS)

Gong, Wenping; Schuttelaars, Henk; Zhang, Heng

2016-05-01

Different types of tidal asymmetry (see review of de Swart and Zimmerman Annu Rev Fluid Mech 41: 203-229, 2009) are examined in this study. We distinguish three types of tidal asymmetry: duration and magnitude differences between flood and ebb tidal flow, duration difference between the rising and falling tides. For waterborne substance transport, the first two asymmetries are important while the last one is not. In this study, we take the Huangmaohai Estuary (HE), Pearl River Delta, China as an example to examine the spatio-temporal variations of the tidal asymmetry in a mixed semidiurnal tidal regime and to explain them by investigating the associated mechanisms. The methodology defining the tidal duration asymmetry and velocity skewness, proposed by Nidzieko (J Geophys Res 115: C08006. doi: 10.1029/2009JC005864 Target Address="10.1029/2009JC005864" TargetType="DOI"/> , 2010) and synthesized by Song et al. (J Geophys Res 116: C12007. doi: 10.1029/2011JC007270 Target Address="10.1029/2011JC007270" TargetType="DOI"/> , 2011), is utilized here and referred to as tidal duration asymmetry (TDA) and flow velocity asymmetry (FVA), respectively. The methodology is further used to quantify the flow duration asymmetry (FDA). A positive asymmetry means a shorter duration of low water slack for FDA, a shorter duration of the rising tide for TDA, and a flood dominance for FVA and vice versa. The Regional Ocean Modeling System (ROMS) model is used to provide relatively long-term water elevation and velocity data and to conduct diagnostic experiments. In the HE, the main tidal constituents are diurnal tides K 1, O 1 and semidiurnal tides M 2 and S 2. The interaction among the diurnal and semidiurnal tides generates a negative tidal asymmetry, while the interactions among semidiurnal tides and their overtides or compound tides result in a positive tidal asymmetry. The

Beam-Target Helicity Asymmetry for γ[over →]n[over →]→π^{-}p in the N^{*} Resonance Region.

PubMed

Ho, D; Peng, P; Bass, C; Collins, P; D'Angelo, A; Deur, A; Fleming, J; Hanretty, C; Kageya, T; Khandaker, M; Klein, F J; Klempt, E; Laine, V; Lowry, M M; Lu, H; Nepali, C; Nikonov, V A; O'Connell, T; Sandorfi, A M; Sarantsev, A V; Schumacher, R A; Strakovsky, I I; Švarc, A; Walford, N K; Wei, X; Whisnant, C S; Workman, R L; Zonta, I; Adhikari, K P; Adikaram, D; Akbar, Z; Amaryan, M J; Anefalos Pereira, S; Avakian, H; Ball, J; Bashkanov, M; Battaglieri, M; Batourine, V; Bedlinskiy, I; Biselli, A; Briscoe, W J; Burkert, V D; Carman, D S; Celentano, A; Charles, G; Chetry, T; Ciullo, G; Clark, L; Colaneri, L; Cole, P L; Contalbrigo, M; Crede, V; Dashyan, N; De Sanctis, E; De Vita, R; Djalali, C; Dupre, R; El Alaoui, A; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fegan, S; Fersch, R; Filippi, A; Fradi, A; Ghandilyan, Y; Gilfoyle, G P; Girod, F X; Glazier, D I; Gleason, C; Gohn, W; Golovatch, E; Gothe, R W; Griffioen, K A; Guidal, M; Guo, L; Hakobyan, H; Harrison, N; Hattawy, M; Hicks, K; Holtrop, M; Hughes, S M; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Jenkins, D; Jiang, H; Jo, H S; Joo, K; Joosten, S; Keller, D; Khachatryan, G; Kim, A; Kim, W; Klein, A; Kubarovsky, V; Kuleshov, S V; Lanza, L; Lenisa, P; Livingston, K; MacGregor, I J D; Markov, N; McKinnon, B; Mineeva, T; Mokeev, V; Montgomery, R A; Movsisyan, A; Munoz Camacho, C; Murdoch, G; Niccolai, S; Niculescu, G; Osipenko, M; Paolone, M; Paremuzyan, R; Park, K; Pasyuk, E; Phelps, W; Pogorelko, O; Price, J W; Procureur, S; Protopopescu, D; Ripani, M; Riser, D; Ritchie, B G; Rizzo, A; Rosner, G; Sabatié, F; Salgado, C; Sharabian, Y G; Skorodumina, Iu; Smith, G D; Sober, D I; Sokhan, D; Sparveris, N; Strauch, S; Tian, Ye; Torayev, B; Ungaro, M; Voskanyan, H; Voutier, E; Watts, D P; Wood, M H; Zachariou, N; Zhang, J; Zhao, Z W

2017-06-16

We report the first beam-target double-polarization asymmetries in the γ+n(p)→π^{-}+p(p) reaction spanning the nucleon resonance region from invariant mass W=1500 to 2300 MeV. Circularly polarized photons and longitudinally polarized deuterons in solid hydrogen deuteride (HD) have been used with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. The exclusive final state has been extracted using three very different analyses that show excellent agreement, and these have been used to deduce the E polarization observable for an effective neutron target. These results have been incorporated into new partial wave analyses and have led to significant revisions for several γnN^{*} resonance photocouplings.

Evaluation of Limb Load Asymmetry Using Two New Mathematical Models

PubMed Central

Kumar, Senthil NS; Omar, Baharudin; Joseph, Leonard H.; Htwe, Ohnmar; Jagannathan, K.; Hamdan, Nor M Y; Rajalakshmi, D.

2015-01-01

Quantitative measurement of limb loading is important in orthopedic and neurological rehabilitation. In current practice, mathematical models such as Symmetry index (SI), Symmetry ratio (SR), and Symmetry angle (SA) are used to quantify limb loading asymmetry. Literatures have identified certain limitations with the above mathematical models. Hence this study presents two new mathematical models Modified symmetry index (MSI) and Limb loading error (LLE) that would address these limitations. Furthermore, the current mathematical models were compared against the new model with the goal of achieving a better model. This study uses hypothetical data to simulate an algorithmic preliminary computational measure to perform with all numerical possibilities of even and uneven limb loading that can occur in human legs. Descriptive statistics are used to interpret the limb loading patterns: symmetry, asymmetry and maximum asymmetry. The five mathematical models were similar in analyzing symmetry between limbs. However, for asymmetry and maximum asymmetry data, the SA and SR values do not give any meaningful interpretation, and SI gives an inflated value. The MSI and LLE are direct, easy to interpret and identify the loading patterns with the side of asymmetry. The new models are notable as they quantify the amount and side of asymmetry under different loading patterns. PMID:25716372

A search asymmetry reversed by figure-ground assignment.

PubMed

Humphreys, G W; Müller, H

2000-05-01

We report evidence demonstrating that a search asymmetry favoring concave over convex targets can be reversed by altering the figure-ground assignment of edges in shapes. Visual search for a concave target among convex distractors is faster than search for a convex target among concave distractors (a search asymmetry). By using shapes with ambiguous local figure-ground relations, we demonstrated that search can be efficient (with search slopes around 10 ms/item) or inefficient (with search slopes around 30-40 ms/item) with the same stimuli, depending on whether edges are assigned to concave or convex "figures." This assignment process can operate in a top-down manner, according to the task set. The results suggest that attention is allocated to spatial regions following the computation of figure-ground relations in parallel across the elements present. This computation can also be modulated by top-down processes.

Search asymmetry and eye movements in infants and adults.

PubMed

Adler, Scott A; Gallego, Pamela

2014-08-01

Search asymmetry is characterized by the detection of a feature-present target amidst feature-absent distractors being efficient and unaffected by the number of distractors, whereas detection of a feature-absent target amidst feature-present distractors is typically inefficient and affected by the number of distractors. Although studies have attempted to investigate this phenomenon with infants (e.g., Adler, Inslicht, Rovee-Collier, & Gerhardstein in Infant Behavioral Development, 21, 253-272, 1998; Colombo, Mitchell, Coldren, & Atwater in Journal of Experimental Psychology: Learning, Memory and Cognition, 19, 98-109, 1990), due to methodological limitations, their findings have been unable to definitively establish the development of visual search mechanisms in infants. The present study assessed eye movements as a means to examine an asymmetry in responding to feature-present versus feature-absent targets in 3-month-olds, relative to adults. Saccade latencies to localize a target (or a distractor, as in the homogeneous conditions) were measured as infants and adults randomly viewed feature-present (R among Ps), feature-absent (P among Rs), and homogeneous (either all Rs or all Ps) arrays at set sizes of 1, 3, 5, and 8. Results indicated that neither infants' nor adults' saccade latencies to localize the target in the feature-present arrays were affected by increasing set sizes, suggesting that localization of the target was efficient. In contrast, saccade latencies to localize the target in the feature-absent arrays increased with increasing set sizes for both infants and adults, suggesting an inefficient localization. These findings indicate that infants exhibit an asymmetry consistent with that found with adults, providing support for functional bottom-up selective attention mechanisms in early infancy.

Parity-violating electroweak asymmetry in e→ p scattering

NASA Astrophysics Data System (ADS)

Aniol, K. A.; Armstrong, D. S.; Averett, T.; Baylac, M.; Burtin, E.; Calarco, J.; Cates, G. D.; Cavata, C.; Chai, Z.; Chang, C. C.; Chen, J.-P.; Chudakov, E.; Cisbani, E.; Coman, M.; Dale, D.; Deur, A.; Djawotho, P.; Epstein, M. B.; Escoffier, S.; Ewell, L.; Falletto, N.; Finn, J. M.; Fissum, K.; Fleck, A.; Frois, B.; Frullani, S.; Gao, J.; Garibaldi, F.; Gasparian, A.; Gerstner, G. M.; Gilman, R.; Glamazdin, A.; Gomez, J.; Gorbenko, V.; Hansen, O.; Hersman, F.; Higinbotham, D. W.; Holmes, R.; Holtrop, M.; Humensky, T. B.; Incerti, S.; Iodice, M.; de Jager, C. W.; Jardillier, J.; Jiang, X.; Jones, M. K.; Jorda, J.; Jutier, C.; Kahl, W.; Kelly, J. J.; Kim, D. H.; Kim, M.-J.; Kim, M. S.; Kominis, I.; Kooijman, E.; Kramer, K.; Kumar, K. S.; Kuss, M.; Lerose, J.; de Leo, R.; Leuschner, M.; Lhuillier, D.; Liang, M.; Liyanage, N.; Lourie, R.; Madey, R.; Malov, S.; Margaziotis, D. J.; Marie, F.; Markowitz, P.; Martino, J.; Mastromarino, P.; McCormick, K.; McIntyre, J.; Meziani, Z.-E.; Michaels, R.; Milbrath, B.; Miller, G. W.; Mitchell, J.; Morand, L.; Neyret, D.; Pedrisat, C.; Petratos, G. G.; Pomatsalyuk, R.; Price, J. S.; Prout, D.; Punjabi, V.; Pussieux, T.; Quéméner, G.; Ransome, R. D.; Relyea, D.; Roblin, Y.; Roche, J.; Rutledge, G. A.; Rutt, P. M.; Rvachev, M.; Sabatie, F.; Saha, A.; Souder, P. A.; Spradlin, M.; Strauch, S.; Suleiman, R.; Templon, J.; Teresawa, T.; Thompson, J.; Tieulent, R.; Todor, L.; Tonguc, B. T.; Ulmer, P. E.; Urciuoli, G. M.; Vlahovic, B.; Wijesooriya, K.; Wilson, R.; Wojtsekhowski, B.; Woo, R.; Xu, W.; Younus, I.; Zhang, C.

2004-06-01

We have measured the parity-violating electroweak asymmetry in the elastic scattering of polarized electrons from protons. Significant contributions to this asymmetry could arise from the contributions of strange form factors in the nucleon. The measured asymmetry is A= -15.05±0.98 (stat) ±0.56 (syst) ppm at the kinematic point < θlab > =12.3° and < Q2 > =0.477 (GeV/c)2 . Based on these data as well as data on electromagnetic form factors, we extract the linear combination of strange form factors GsE +0.392 GsM = 0.014±0.020±0.010 , where the first error arises from this experiment and the second arises from the electromagnetic form factor data. This paper provides a full description of the special experimental techniques employed for precisely measuring the small asymmetry, including the first use of a strained GaAs crystal and a laser-Compton polarimeter in a fixed target parity-violation experiment.

First measurement of target and double spin asymmetries for e-vectorp-vector{yields}ep{pi}{sup 0} in the nucleon resonance region above the {delta}(1232)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biselli, A. S.; Burkert, V. D.; Avakian, H.

2008-10-15

The exclusive channel p-vectore-vector,e{sup '}p){pi}{sup 0} was studied in the first and second nucleon resonance regions in the Q{sup 2} range from 0.187 to 0.770 GeV{sup 2} at Jefferson Lab using the CEBAF Large Acceptance Spectrometer. Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the {pi}{sup 0} and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data set, once includedmore » in the global fits of the above models, is expected to place strong constraints on the electrocoupling amplitudes A{sub 1/2} and S{sub 1/2} for the Roper resonance N(1400)P{sub 11} and the N(1535)S{sub 11} and N(1520)D{sub 13} states.« less

First measurement of target and double spin asymmetries for polarized e- polarized p --> e p pi0 in the nucleon resonance region above the Delta(1232)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biselli, Angela; Burkert, Volker; Amaryan, Moscov

2008-10-01

DOI: http://dx.doi.org/10.1103/PhysRevC.78.045204 The exclusive channel polarized proton(polarized e,e prime p)pi0 was studied in the first and second nucleon resonance regions in the Q2 range from 0.187 to 0.770 GeV2 at Jefferson Lab using the CEBAF Large Acceptance Spectrometer (CLAS). Longitudinal target and beam-target asymmetries were extracted over a large range of center-of-mass angles of the pi0 and compared to the unitary isobar model MAID, the dynamic model by Sato and Lee, and the dynamic model DMT. A strong sensitivity to individual models was observed, in particular for the target asymmetry and in the higher invariant mass region. This data set,more » once included in the global fits of the above models, is expected to place strong constraints on the electrocoupling amplitudes A_{1/2} and S_{1/2} for the Roper resonance N(1400)P11, and the N(1535)S11 and N(1520)D13 states.« less

Design of all-optical, hot-electron current-direction-switching device based on geometrical asymmetry

PubMed Central

Kumarasinghe, Chathurangi S.; Premaratne, Malin; Gunapala, Sarath D.; Agrawal, Govind P.

2016-01-01

We propose a nano-scale current-direction-switching device(CDSD) that operates based on the novel phenomenon of geometrical asymmetry between two hot-electron generating plasmonic nanostructures. The proposed device is easy to fabricate and economical to develop compared to most other existing designs. It also has the ability to function without external wiring in nano or molecular circuitry since it is powered and controlled optically. We consider a such CDSD made of two dissimilar nanorods separated by a thin but finite potential barrier and theoretically derive the frequency-dependent electron/current flow rate. Our analysis takes in to account the quantum dynamics of electrons inside the nanorods under a periodic optical perturbation that are confined by nanorod boundaries, modelled as finite cylindrical potential wells. The influence of design parameters, such as geometric difference between the two nanorods, their volumes and the barrier width on quality parameters such as frequency-sensitivity of the current flow direction, magnitude of the current flow, positive to negative current ratio, and the energy conversion efficiency is discussed by considering a device made of Ag/TiO2/Ag. Theoretical insight and design guidelines presented here are useful for customizing our proposed CDSD for applications such as self-powered logic gates, power supplies, and sensors. PMID:26887286

Design of all-optical, hot-electron current-direction-switching device based on geometrical asymmetry.

PubMed

Kumarasinghe, Chathurangi S; Premaratne, Malin; Gunapala, Sarath D; Agrawal, Govind P

2016-02-18

We propose a nano-scale current-direction-switching device(CDSD) that operates based on the novel phenomenon of geometrical asymmetry between two hot-electron generating plasmonic nanostructures. The proposed device is easy to fabricate and economical to develop compared to most other existing designs. It also has the ability to function without external wiring in nano or molecular circuitry since it is powered and controlled optically. We consider a such CDSD made of two dissimilar nanorods separated by a thin but finite potential barrier and theoretically derive the frequency-dependent electron/current flow rate. Our analysis takes in to account the quantum dynamics of electrons inside the nanorods under a periodic optical perturbation that are confined by nanorod boundaries, modelled as finite cylindrical potential wells. The influence of design parameters, such as geometric difference between the two nanorods, their volumes and the barrier width on quality parameters such as frequency-sensitivity of the current flow direction, magnitude of the current flow, positive to negative current ratio, and the energy conversion efficiency is discussed by considering a device made of Ag/TiO2/Ag. Theoretical insight and design guidelines presented here are useful for customizing our proposed CDSD for applications such as self-powered logic gates, power supplies, and sensors.

SANE's Measurement of the Proton's Virtual Photon Spin Asymmetry, A p 1, at Large Bjorken x

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mulholland, Jonathan

2012-05-01

The experiment SANE (Spin Asymmetries of the Nucleon Experiment) measured inclusive double polarization electron asymmetries on a proton target at the Continuous Electron Beam Accelerator Facility at the Thomas Jefferson National Laboratory in Newport News Virgina. Polarized electrons were scattered from a solid 14NH 3 polarized target provided by the University of Virginia target group. Measurements were taken with the target polarization oriented at 80 degrees and 180 degrees relative to the beam direction, and beam energies of 4.7 and 5.9 GeV were used. Scattered electrons were detected by a multi-component novel non-magnetic detector package constructed for this experiment. Asymmetriesmore » measured at the two target orientations allow for the extraction of the virtual Compton asymmetries A 1 p and A 2 p as well as the spin structure functions g 1 p and g 2 p. This work addresses the extraction of the virtual Compton asymmetry A 1 p in the deep inelastic regime. The analysis uses data in the kinematic range from Bjorken x of 0.30 to 0.55, separated into four Q 2 bins from 1.9 to 4.7 GeV 2.« less

Lean Mass Asymmetry Influences Force and Power Asymmetry During Jumping in Collegiate Athletes

PubMed Central

Bell, David R.; Sanfilippo, Jennifer L.; Binkley, Neil; Heiderscheit, Bryan C.

2015-01-01

The purpose of this investigation was to: (1) examine how asymmetry in lower extremity lean mass influenced force and power asymmetry during jumping, (2) determine how power and force asymmetry affected jump height, and (3) report normative values in collegiate athletes. Force and power were assessed from each limb using bilateral force plates during a countermovement jump in 167 Division 1 athletes (mass=85.7±20.3kg, age=20.0±1.2years, 103M/64F). Lean mass of the pelvis, thigh, and shank was assessed via dual-energy X-ray absorptiometry. Percent asymmetry was calculated for lean mass at each region (pelvis, thigh, and shank) as well as force and power. Forward stepwise regressions were performed to determine the influence of lean mass asymmetry on force and power asymmetry. Thigh and shank lean mass asymmetry explained 20% of the variance in force asymmetry (R2=0.20, P<0.001), while lean mass asymmetry of the pelvis, thigh and shank explained 25% of the variance in power asymmetry (R2=0.25, P<0.001). Jump height was compared across level of force and power asymmetry (P>0.05) and greater than 10% asymmetry in power tended to decrease performance (effect size>1.0). Ninety-five percent of this population (2.5th to 97.5th percentile) displayed force asymmetry between −11.8 to 16.8% and a power asymmetry between −9.9 to 11.5%. A small percentage (<4%) of these athletes displayed more than 15% asymmetry between limbs. These results demonstrate that lean mass asymmetry in the lower extremity is at least partially responsible for asymmetries in force and power. However, a large percentage remains unexplained by lean mass asymmetry. PMID:24402449

Lean mass asymmetry influences force and power asymmetry during jumping in collegiate athletes.

PubMed

Bell, David R; Sanfilippo, Jennifer L; Binkley, Neil; Heiderscheit, Bryan C

2014-04-01

The purpose of this investigation was to (a) examine how asymmetry in lower extremity lean mass influenced force and power asymmetry during jumping, (b) determine how power and force asymmetry affected jump height, and (c) report normative values in collegiate athletes. Force and power were assessed from each limb using bilateral force plates during a countermovement jump in 167 division 1 athletes (mass = 85.7 ± 20.3 kg, age = 20.0 ± 1.2 years; 103 men and 64 women). Lean mass of the pelvis, thigh, and shank was assessed using dual-energy x-ray absorptiometry. Percent asymmetry was calculated for lean mass at each region (pelvis, thigh, and shank) as well as force and power. Forward stepwise regressions were performed to determine the influence of lean mass asymmetry on force and power asymmetry. Thigh and shank lean mass asymmetry explained 20% of the variance in force asymmetry (R = 0.20, p < 0.001), whereas lean mass asymmetry of the pelvis, thigh, and shank explained 25% of the variance in power asymmetry (R = 0.25, p < 0.001). Jump height was compared across level of force and power asymmetry (p > 0.05) and greater than 10% asymmetry in power tended to decrease the performance (effect size >1.0). Ninety-five percent of this population (2.5th to 97.5th percentile) displayed force asymmetry between -11.8 and 16.8% and a power asymmetry between -9.9 and 11.5%. A small percentage (<4%) of these athletes displayed more than 15% asymmetry between limbs. These results demonstrate that lean mass asymmetry in the lower extremity is at least partially responsible for asymmetries in force and power. However, a large percentage remains unexplained by lean mass asymmetry.

Nasopupillary asymmetry.

PubMed

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

2014-01-01

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

Quantum asymmetry between time and space

PubMed Central

2016-01-01

An asymmetry exists between time and space in the sense that physical systems inevitably evolve over time, whereas there is no corresponding ubiquitous translation over space. The asymmetry, which is presumed to be elemental, is represented by equations of motion and conservation laws that operate differently over time and space. If, however, the asymmetry was found to be due to deeper causes, this conventional view of time evolution would need reworking. Here we show, using a sum-over-paths formalism, that a violation of time reversal (T) symmetry might be such a cause. If T symmetry is obeyed, then the formalism treats time and space symmetrically such that states of matter are localized both in space and in time. In this case, equations of motion and conservation laws are undefined or inapplicable. However, if T symmetry is violated, then the same sum over paths formalism yields states that are localized in space and distributed without bound over time, creating an asymmetry between time and space. Moreover, the states satisfy an equation of motion (the Schrödinger equation) and conservation laws apply. This suggests that the time–space asymmetry is not elemental as currently presumed, and that T violation may have a deep connection with time evolution. PMID:26997899

Facial Asymmetry: Brow and Ear Position.

PubMed

Perumal, Balaji; Meyer, Dale R

2018-04-01

The purpose of the current study was to analyze brow and ear position, and examine the relationship between these structures in patients presenting for blepharoplasty evaluation. A retrospective chart review was performed, which included all patients presenting to one oculoplastic physician for a blepharoplasty evaluation from November, 2012 to March, 2014. The prevalence of brow ptosis and brow and ear asymmetry was calculated; the proportional distribution was determined, and chi-square analysis and the z-test of proportions were used to calculate the significance. Institutional Review Board approval was obtained for this study. A total of 133 patients met the inclusion criteria. Some degree of brow ptosis was noted in 83% of patients. Brow asymmetry was found in 88% of patients, and ear asymmetry in 77%. Of those patients who had asymmetry, 61% had the right brow lower and 75% had the right ear lower; 73% of all patients had the brow and ear lower on the same side ( p  < 0.001). In this study, brow ptosis and asymmetry were quite common. In addition, the side of the lower brow correlated strongly with the side of the lower ear, and the right side structures were lower more often than the left. Patients presenting for blepharoplasty evaluation may have an element of generalized facial asymmetry which includes the brows and ears. These observations can be important for preoperative planning and patient counseling. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Vertical ground reaction force during standing and walking: Are they related to bone mineral density left-right asymmetries?

PubMed

Brozgol, Marina; Arbiv, Mira; Mirelman, Anat; Herman, Talia; Hausdorff, Jeffrey M; Vaisman, Nachum

2017-05-01

Osteoporosis is a systemic skeletal disease that is characterized by reduced bone mass, deterioration of bone tissue and skeletal fragility. The purpose of the current study was to determine whether asymmetrical femur bone mineral density (BMD) is associated with asymmetrical gait and standing. We compared measures of gait and standing asymmetry in subjects with (n=38) and without (n=11) significant left-right differences in BMD. Participants walked for 72m at their comfortable speed and stood quietly for 60s while outfitted with pressure-sensitive insoles. Based on the pressure measurements, indices of standing and gait asymmetry were determined. Gait Asymmetry (GA) indices of maximum ground reaction force (GRF) and stance time were significantly higher in the asymmetrical BMD group, compared to the symmetrical group (p<0.03). During quiet standing, maximal GRF was twice as high in those with BMD asymmetry, compared to those without, although this difference was not statistically significant (p=0.10). These preliminary findings indicate that femur BMD asymmetry and gait asymmetry are interrelated in otherwise healthy adults. Nutrition, metabolism and lifestyle are known contributors to BMD; typically, they affect bone health symmetrically. We suggest, therefore, that the BMD asymmetry may be due to previous changes in the loading pattern during walking that might have led to asymmetric bone deterioration. Future larger scale and prospective studies are needed to identify the mechanisms underlying the relationship between standing, gait and BMD and to explore whether gait training and exercises that target gait symmetry might help to reduce BMD asymmetry. Copyright © 2017 Elsevier B.V. All rights reserved.

Hemispheric asymmetry in the efficiency of attentional networks.

PubMed

Asanowicz, Dariusz; Marzecová, Anna; Jaśkowski, Piotr; Wolski, Piotr

2012-07-01

Despite the fact that hemispheric asymmetry of attention has been widely studied, a clear picture of this complex phenomenon is still lacking. The aim of the present study was to provide an efficient and reliable measurement of potential hemispheric asymmetries of three attentional networks, i.e. alerting, orienting and executive attention. Participants (N=125) were tested with the Lateralized Attention Network Test (LANT) that allowed us to investigate the efficiency of the networks in both visual fields (VF). We found a LVF advantage when a target occurred in an unattended location, which seems to reflect right hemisphere superiority in control of the reorienting of attention. Furthermore, a LVF advantage in conflict resolution was observed, which may indicate hemispheric asymmetry of the executive network. No VF effect for alerting was found. The results, consistent with the common notion of general right hemisphere dominance for attention, provide a more detailed account of hemispheric asymmetries of the attentional networks than previous studies using the LANT task. Copyright © 2012 Elsevier Inc. All rights reserved.

Reconnection at three dimensional magnetic null points: Effect of current sheet asymmetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wyper, P. F.; Jain, Rekha

2013-05-15

Asymmetric current sheets are likely to be prevalent in both astrophysical and laboratory plasmas with complex three dimensional (3D) magnetic topologies. This work presents kinematic analytical models for spine and fan reconnection at a radially symmetric 3D null (i.e., a null where the eigenvalues associated with the fan plane are equal) with asymmetric current sheets. Asymmetric fan reconnection is characterized by an asymmetric reconnection of flux past each spine line and a bulk flow of plasma across the null point. In contrast, asymmetric spine reconnection is characterized by the reconnection of an equal quantity of flux across the fan planemore » in both directions. The higher modes of spine reconnection also include localized wedges of vortical flux transport in each half of the fan. In this situation, two definitions for reconnection rate become appropriate: a local reconnection rate quantifying how much flux is genuinely reconnected across the fan plane and a global rate associated with the net flux driven across each semi-plane. Through a scaling analysis, it is shown that when the ohmic dissipation in the layer is assumed to be constant, the increase in the local rate bleeds from the global rate as the sheet deformation is increased. Both models suggest that asymmetry in the current sheet dimensions will have a profound effect on the reconnection rate and manner of flux transport in reconnection involving 3D nulls.« less

Parallel Processing in Visual Search Asymmetry

ERIC Educational Resources Information Center

Dosher, Barbara Anne; Han, Songmei; Lu, Zhong-Lin

2004-01-01

The difficulty of visual search may depend on assignment of the same visual elements as targets and distractors-search asymmetry. Easy C-in-O searches and difficult O-in-C searches are often associated with parallel and serial search, respectively. Here, the time course of visual search was measured for both tasks with speed-accuracy methods. The…

Sources of Local Time Asymmetries in Magnetodiscs

NASA Astrophysics Data System (ADS)

Arridge, C. S.; Kane, M.; Sergis, N.; Khurana, K. K.; Jackman, C. M.

2015-04-01

The rapidly rotating magnetospheres at Jupiter and Saturn contain a near-equatorial thin current sheet over most local times known as the magnetodisc, resembling a wrapped-up magnetotail. The Pioneer, Voyager, Ulysses, Galileo, Cassini and New Horizons spacecraft at Jupiter and Saturn have provided extensive datasets from which to observationally identify local time asymmetries in these magnetodiscs. Imaging in the infrared and ultraviolet from ground- and space-based instruments have also revealed the presence of local time asymmetries in the aurora which therefore must map to local time asymmetries in the magnetosphere. Asymmetries are found in (i) the configuration of the magnetic field and magnetospheric currents, where a thicker disc is found in the noon and dusk sectors; (ii) plasma flows where the plasma flow has local time-dependent radial components; (iii) a thicker plasma sheet in the dusk sector. Many of these features are also reproduced in global MHD simulations. Several models have been developed to interpret these various observations and typically fall into two groups: ones which invoke coupling with the solar wind (via reconnection or viscous processes) and ones which invoke internal rotational processes operating inside an asymmetrical external boundary. In this paper we review these observational in situ findings, review the models which seek to explain them, and highlight open questions and directions for future work.

From symmetry to asymmetry: Phylogenetic patterns of asymmetry variation in animals and their evolutionary significance

PubMed Central

Palmer, A. Richard

1996-01-01

Phylogenetic analyses of asymmetry variation offer a powerful tool for exploring the interplay between ontogeny and evolution because (i) conspicuous asymmetries exist in many higher metazoans with widely varying modes of development, (ii) patterns of bilateral variation within species may identify genetically and environmentally triggered asymmetries, and (iii) asymmetries arising at different times during development may be more sensitive to internal cytoplasmic inhomogeneities compared to external environmental stimuli. Using four broadly comparable asymmetry states (symmetry, antisymmetry, dextral, and sinistral), and two stages at which asymmetry appears developmentally (larval and postlarval), I evaluated relations between ontogenetic and phylogenetic patterns of asymmetry variation. Among 140 inferred phylogenetic transitions between asymmetry states, recorded from 11 classes in five phyla, directional asymmetry (dextral or sinistral) evolved directly from symmetrical ancestors proportionally more frequently among larval asymmetries. In contrast, antisymmetry, either as an end state or as a transitional stage preceding directional asymmetry, was confined primarily to postlarval asymmetries. The ontogenetic origin of asymmetry thus significantly influences its subsequent evolution. Furthermore, because antisymmetry typically signals an environmentally triggered asymmetry, the phylogenetic transition from antisymmetry to directional asymmetry suggests that many cases of laterally fixed asymmetries evolved via genetic assimilation. PMID:8962039

Structural white matter asymmetries in relation to functional asymmetries during speech perception and production.

PubMed

Ocklenburg, Sebastian; Hugdahl, Kenneth; Westerhausen, René

2013-12-01

Functional hemispheric asymmetries of speech production and perception are a key feature of the human language system, but their neurophysiological basis is still poorly understood. Using a combined fMRI and tract-based spatial statistics approach, we investigated the relation of microstructural asymmetries in language-relevant white matter pathways and functional activation asymmetries during silent verb generation and passive listening to spoken words. Tract-based spatial statistics revealed several leftward asymmetric clusters in the arcuate fasciculus and uncinate fasciculus that were differentially related to activation asymmetries in the two functional tasks. Frontal and temporal activation asymmetries during silent verb generation were positively related to the strength of specific microstructural white matter asymmetries in the arcuate fasciculus. In contrast, microstructural uncinate fasciculus asymmetries were related to temporal activation asymmetries during passive listening. These findings suggest that white matter asymmetries may indeed be one of the factors underlying functional hemispheric asymmetries. Moreover, they also show that specific localized white matter asymmetries might be of greater relevance for functional activation asymmetries than microstructural features of whole pathways. © 2013.

HARD X-RAY ASYMMETRY LIMITS IN SOLAR FLARE CONJUGATE FOOTPOINTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daou, Antoun G.; Alexander, David, E-mail: agdaou@rice.edu, E-mail: dalex@rice.edu

2016-11-20

The transport of energetic electrons in a solar flare is modeled using a time-dependent one-dimensional Fokker–Planck code that incorporates asymmetric magnetic convergence. We derive the temporal and spectral evolution of the resulting hard X-ray (HXR) emission in the conjugate chromospheric footpoints, assuming thick target photon production, and characterize the time evolution of the numerically simulated footpoint asymmetry and its relationship to the photospheric magnetic configuration. The thick target HXR asymmetry in the conjugate footpoints is found to increase with magnetic field ratio as expected. However, we find that the footpoint HXR asymmetry saturates for conjugate footpoint magnetic field ratios ≥4.more » This result is borne out in a direct comparison with observations of 44 double-footpoint flares. The presence of such a limit has not been reported before, and may serve as both a theoretical and observational benchmark for testing a range of particle transport and flare morphology constraints, particularly as a means to differentiate between isotropic and anisotropic particle injection.« less

Effects of fuel-capsule shimming and drive asymmetry on inertial-confinement-fusion symmetry and yield

DOE Office of Scientific and Technical Information (OSTI.GOV)

Séguin, F. H.; Li, C. K.; DeCiantis, J. L.

Three orthogonal proton emission imaging cameras were used to study the 3D effects of low-mode drive asymmetries and target asymmetries on nuclear burn symmetry and yield in direct-drive, inertial-confinement-fusion experiments. The fusion yield decreased quickly as the burn region became asymmetric due to either drive or capsule asymmetry. Measurements and analytic scaling are used to predict how intentionally asymmetric capsule shells could improve performance by compensating for drive asymmetry when it cannot be avoided (such as with indirect drive or with polar direct drive).

Effects of fuel-capsule shimming and drive asymmetry on inertial-confinement-fusion symmetry and yield

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seguin, F. H.; Li, C. K.; DeCiantis, J. L.

Three orthogonal proton emission imaging cameras were used to study the 3D effects of low-mode drive asymmetries and target asymmetries on nuclear burn symmetry and yield in direct-drive, inertial-confinement-fusion experiments. The fusion yield decreased quickly as the burn region became asymmetric due to either drive or capsule asymmetry. Furthermore, measurements and analytic scaling are used to predict how intentionally asymmetric capsule shells could improve performance by compensating for drive asymmetry when it cannot be avoided (such as with indirect drive or with polar direct drive).

Effects of fuel-capsule shimming and drive asymmetry on inertial-confinement-fusion symmetry and yield

DOE PAGES

Seguin, F. H.; Li, C. K.; DeCiantis, J. L.; ...

2016-03-22

Three orthogonal proton emission imaging cameras were used to study the 3D effects of low-mode drive asymmetries and target asymmetries on nuclear burn symmetry and yield in direct-drive, inertial-confinement-fusion experiments. The fusion yield decreased quickly as the burn region became asymmetric due to either drive or capsule asymmetry. Furthermore, measurements and analytic scaling are used to predict how intentionally asymmetric capsule shells could improve performance by compensating for drive asymmetry when it cannot be avoided (such as with indirect drive or with polar direct drive).

Mitigating the impact of hohlraum asymmetries in National Ignition Facility implosions using capsule shims

DOE PAGES

Clark, D. S.; Weber, C. R.; Smalyuk, V. A.; ...

2016-07-22

Here, current indirect drive implosion experiments on the National Ignition Facility (NIF) are believed to be strongly impacted by long wavelength perturbations driven by asymmetries in the hohlraum x-ray flux. To address this perturbation source, active efforts are underway to develop modified hohlraum designs with reduced asymmetry imprint. An alternative strategy, however, is to modify the capsule design to be more resilient to a given amount of hohlraum asymmetry. In particular, the capsule may be deliberately misshaped, or “shimmed,” so as to counteract the expected asymmetries from the hohlraum. Here, the efficacy of capsule shimming to correct the asymmetries inmore » two recent NIF implosion experiments is assessed using two-dimensional radiation hydrodynamics simulations. Despite the highly time-dependent character of the asymmetries and the high convergence ratios of these implosions, simulations suggest that shims could be highly effective at counteracting current asymmetries and result in factors of a few enhancements in neutron yields. For higher compression designs, the yield improvement could be even greater.« less

Mitigating the impact of hohlraum asymmetries in National Ignition Facility implosions using capsule shims

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, D. S.; Weber, C. R.; Smalyuk, V. A.

2016-07-15

Current indirect drive implosion experiments on the National Ignition Facility (NIF) [Moses et al., Phys. Plasmas 16, 041006 (2009)] are believed to be strongly impacted by long wavelength perturbations driven by asymmetries in the hohlraum x-ray flux. To address this perturbation source, active efforts are underway to develop modified hohlraum designs with reduced asymmetry imprint. An alternative strategy, however, is to modify the capsule design to be more resilient to a given amount of hohlraum asymmetry. In particular, the capsule may be deliberately misshaped, or “shimmed,” so as to counteract the expected asymmetries from the hohlraum. Here, the efficacy ofmore » capsule shimming to correct the asymmetries in two recent NIF implosion experiments is assessed using two-dimensional radiation hydrodynamics simulations. Despite the highly time-dependent character of the asymmetries and the high convergence ratios of these implosions, simulations suggest that shims could be highly effective at counteracting current asymmetries and result in factors of a few enhancements in neutron yields. For higher compression designs, the yield improvement could be even greater.« less

Cholinergic left-right asymmetry in the habenulo-interpeduncular pathway.

PubMed

Hong, Elim; Santhakumar, Kirankumar; Akitake, Courtney A; Ahn, Sang Jung; Thisse, Christine; Thisse, Bernard; Wyart, Claire; Mangin, Jean-Marie; Halpern, Marnie E

2013-12-24

The habenulo-interpeduncular pathway, a highly conserved cholinergic system, has emerged as a valuable model to study left-right asymmetry in the brain. In larval zebrafish, the bilaterally paired dorsal habenular nuclei (dHb) exhibit prominent left-right differences in their organization, gene expression, and connectivity, but their cholinergic nature was unclear. Through the discovery of a duplicated cholinergic gene locus, we now show that choline acetyltransferase and vesicular acetylcholine transporter homologs are preferentially expressed in the right dHb of larval zebrafish. Genes encoding the nicotinic acetylcholine receptor subunits α2 and β4 are transcribed in the target interpeduncular nucleus (IPN), suggesting that the asymmetrical cholinergic pathway is functional. To confirm this, we activated channelrhodopsin-2 specifically in the larval dHb and performed whole-cell patch-clamp recording of IPN neurons. The response to optogenetic or electrical stimulation of the right dHb consisted of an initial fast glutamatergic excitatory postsynaptic current followed by a slow-rising cholinergic current. In adult zebrafish, the dHb are divided into discrete cholinergic and peptidergic subnuclei that differ in size between the left and right sides of the brain. After exposing adults to nicotine, fos expression was activated in subregions of the IPN enriched for specific nicotinic acetylcholine receptor subunits. Our studies of the newly identified cholinergic gene locus resolve the neurotransmitter identity of the zebrafish habenular nuclei and reveal functional asymmetry in a major cholinergic neuromodulatory pathway of the vertebrate brain.

Single spin asymmetries in charged kaon production from semi-inclusive deep inelastic scattering on a transversely polarized He 3 target

DOE PAGES

Zhao, Y. X.; Wang, Y.; Allada, K.; ...

2014-11-03

We report the first measurement of target single spin asymmetries of charged kaons produced in semi-inclusive deep inelastic scattering of electrons off a transversely polarized 3He target. Both the Collins and Sivers moments, which are related to the nucleon transversity and Sivers distributions, respectively, are extracted over the kinematic range of 0.1 < x bj<0.4 for K + and K – production. While the Collins and Sivers moments for K + are consistent with zero within the experimental uncertainties, both moments for K – favor negative values. The Sivers moments are compared to the theoretical prediction from a phenomenological fitmore » to the world data. While the K + Sivers moments are consistent with the prediction, the K – results differ from the prediction at the 2-sigma level.« less

Search Asymmetry, Sustained Attention, and Response Inhibition

ERIC Educational Resources Information Center

Stevenson, Hugh; Russell, Paul N.; Helton, William S.

2011-01-01

In the present experiment, we used search asymmetry to test whether the sustained attention to response task is a better measure of response inhibition or sustained attention. Participants performed feature present and feature absent target detection tasks using either a sustained attention to response task (SART; high Go low No-Go) or a…

Strongly scale-dependent CMB dipolar asymmetry from super-curvature fluctuations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Byrnes, Christian; Domènech, Guillem; Sasaki, Misao

2016-12-01

We reconsider the observed CMB dipolar asymmetry in the context of open inflation, where a supercurvature mode might survive the bubble nucleation. If such a supercurvature mode modulates the amplitude of the curvature power spectrum, it would easily produce an asymmetry in the power spectrum. We show that current observational data can be accommodated in a three-field model, with simple quadratic potentials and a non-trivial field-space metric. Despite the presence of three fields, we believe this model is so far the simplest that can match current observations. We are able to match the observed strong scale dependence of the dipolarmore » asymmetry, without a fine tuning of initial conditions, breaking slow roll or adding a feature to the evolution of any field.« less

Short-term tidal asymmetry inversion in a macrotidal estuary (Beira, Mozambique)

NASA Astrophysics Data System (ADS)

Nzualo, Teodósio N. M.; Gallo, Marcos N.; Vinzon, Susana B.

2018-05-01

The distortion of the tide in estuaries, bays and coastal areas is the result of the generation of overtides due to the non-linear effects associated with friction, advection, and the finite effects of the tidal amplitude in shallow waters. The Beira estuary is classified as macrotidal, with a large ratio of S2/M2. Typical tides ranges from 6 m and 0.8 m, during springs and neaps tides, respectively. As a consequence of this large fortnightly tidal amplitude difference and the estuarine morphology, asymmetry inversions occur. Two types of tidal asymmetries were investigated in this paper, one considering tidal duration asymmetry (time difference between rising and falling tide) and the other, related to tidal velocity asymmetry (unequal magnitudes of flood and ebb peaks currents). In the Beira estuary when we examine the tidal duration asymmetry, flood dominance is observed during spring tide periods (negative time difference between rising and falling tide), while ebb dominance appears during neap tides (positive time difference between rising and falling tide). A 2DH hydrodynamic model was implemented to analyze this asymmetry inversion. The model was calibrated with water-level data measured at the Port of Beira and current data measured along the estuary. The model was run for different scenarios considering tidal constituents at the ocean boundary, river discharge and the morphology of the estuary. River discharge did not show significant effects on the tidal duration asymmetry. Through comparison of the scenarios, it was shown that the incoming ocean tide at the boundary has an ebb-dominant asymmetry, changing to flood-dominant only during spring tides due to the effect of shoaling and friction within the estuary. During neap tides, the propagation occurs mainly in the channels, and ebb dominance remains. The interplay between the estuary morphodynamics was thus identified and the relation between tidal duration asymmetry and tidal velocity asymmetry was

CMB hemispherical asymmetry from non-linear isocurvature perturbations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Assadullahi, Hooshyar; Wands, David; Firouzjahi, Hassan

2015-04-01

We investigate whether non-adiabatic perturbations from inflation could produce an asymmetric distribution of temperature anisotropies on large angular scales in the cosmic microwave background (CMB). We use a generalised non-linear δ N formalism to calculate the non-Gaussianity of the primordial density and isocurvature perturbations due to the presence of non-adiabatic, but approximately scale-invariant field fluctuations during multi-field inflation. This local-type non-Gaussianity leads to a correlation between very long wavelength inhomogeneities, larger than our observable horizon, and smaller scale fluctuations in the radiation and matter density. Matter isocurvature perturbations contribute primarily to low CMB multipoles and hence can lead to a hemisphericalmore » asymmetry on large angular scales, with negligible asymmetry on smaller scales. In curvaton models, where the matter isocurvature perturbation is partly correlated with the primordial density perturbation, we are unable to obtain a significant asymmetry on large angular scales while respecting current observational constraints on the observed quadrupole. However in the axion model, where the matter isocurvature and primordial density perturbations are uncorrelated, we find it may be possible to obtain a significant asymmetry due to isocurvature modes on large angular scales. Such an isocurvature origin for the hemispherical asymmetry would naturally give rise to a distinctive asymmetry in the CMB polarisation on large scales.« less

Mitigating the impact of hohlraum asymmetries in National Ignition Facility implosions using capsule shims

NASA Astrophysics Data System (ADS)

Clark, Daniel; Weber, Christopher; Smalyuk, Vladimir; Robey, Harry; Kritcher, Andrea; Milovich, Jose; Salmonson, Jay

2016-10-01

Current indirect drive implosion experiments on the National Ignition Facility (NIF) are believed to be strongly impacted by long wavelength perturbations driven by asymmetries in the hohlraum x-ray flux. To address this perturbation source, active efforts are underway to develop modified hohlraum designs with reduced asymmetry imprint. An alternative strategy, however, is to modify the capsule design to be more resilient to a given amount of hohlraum asymmetry. In particular, the capsule may be deliberately misshaped, or ``shimmed,'' so as to counteract the expected asymmetries from the hohlraum. Here, the efficacy of capsule shimming to correct the asymmetries in two recent NIF implosion experiments is assessed using two-dimensional radiation hydrodynamics simulations. Despite the highly time-dependent character of the asymmetries and the high convergence ratios of these implosions, simulations suggest that shims could be highly effective at counteracting current asymmetries and result in factors of a few enhancements in neutron yields. For higher compression designs, the yield improvement could be even greater. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Moral asymmetries in judgments of agency withstand ludicrous causal deviance

PubMed Central

Sousa, Paulo; Holbrook, Colin; Swiney, Lauren

2015-01-01

Americans have been shown to attribute greater intentionality to immoral than to amoral actions in cases of causal deviance, that is, cases where a goal is satisfied in a way that deviates from initially planned means (e.g., a gunman wants to hit a target and his hand slips, but the bullet ricochets off a rock into the target). However, past research has yet to assess whether this asymmetry persists in cases of extreme causal deviance. Here, we manipulated the level of mild to extreme causal deviance of an immoral versus amoral act. The asymmetry in attributions of intentionality was observed at all but the most extreme level of causal deviance, and, as we hypothesized, was mediated by attributions of blame/credit and judgments of action performance. These findings are discussed as they support a multiple-concepts interpretation of the asymmetry, wherein blame renders a naïve concept of intentional action (the outcome matches the intention) more salient than a composite concept (the outcome matches the intention and was brought about by planned means), and in terms of their implications for cross-cultural research on judgments of agency. PMID:26441755

Moral asymmetries in judgments of agency withstand ludicrous causal deviance.

PubMed

Sousa, Paulo; Holbrook, Colin; Swiney, Lauren

2015-01-01

Americans have been shown to attribute greater intentionality to immoral than to amoral actions in cases of causal deviance, that is, cases where a goal is satisfied in a way that deviates from initially planned means (e.g., a gunman wants to hit a target and his hand slips, but the bullet ricochets off a rock into the target). However, past research has yet to assess whether this asymmetry persists in cases of extreme causal deviance. Here, we manipulated the level of mild to extreme causal deviance of an immoral versus amoral act. The asymmetry in attributions of intentionality was observed at all but the most extreme level of causal deviance, and, as we hypothesized, was mediated by attributions of blame/credit and judgments of action performance. These findings are discussed as they support a multiple-concepts interpretation of the asymmetry, wherein blame renders a naïve concept of intentional action (the outcome matches the intention) more salient than a composite concept (the outcome matches the intention and was brought about by planned means), and in terms of their implications for cross-cultural research on judgments of agency.

Cerebellar asymmetry and its relation to cerebral asymmetry estimated by intrinsic functional connectivity

PubMed Central

Wang, Danhong; Buckner, Randy L.

2013-01-01

Asymmetry of the human cerebellum was investigated using intrinsic functional connectivity. Regions of functional asymmetry within the cerebellum were identified during resting-state functional MRI (n = 500 subjects) and replicated in an independent cohort (n = 500 subjects). The most strongly right lateralized cerebellar regions fell within the posterior lobe, including crus I and crus II, in regions estimated to link to the cerebral association cortex. The most strongly left lateralized cerebellar regions were located in lobules VI and VIII in regions linked to distinct cerebral association networks. Comparison of cerebellar asymmetry with independently estimated cerebral asymmetry revealed that the lateralized regions of the cerebellum belong to the same networks that are strongly lateralized in the cerebrum. The degree of functional asymmetry of the cerebellum across individuals was significantly correlated with cerebral asymmetry and varied with handedness. In addition, cerebellar asymmetry estimated at rest predicted cerebral lateralization during an active language task. These results demonstrate that functional lateralization is likely a unitary feature of large-scale cerebrocerebellar networks, consistent with the hypothesis that the cerebellum possesses a roughly homotopic map of the cerebral cortex including the prominent asymmetries of the association cortex. PMID:23076113

Computations of Vertical Displacement Events with Toroidal Asymmetry

NASA Astrophysics Data System (ADS)

Sovinec, C. R.; Bunkers, K. J.

2017-10-01

Nonlinear numerical MHD modeling with the NIMROD code [https://nimrodteam.org] is being developed to investigate asymmetry during vertical displacement events. We start from idealized up/down symmetric tokamak equilibria with small levels of imposed toroidally asymmetric field errors. Vertical displacement results when removing current from one of the two divertor coils. The Eulerian reference-frame modeling uses temperature-dependent resistivity and anisotropic thermal conduction to distinguish the hot plasma region from surrounding cold, low-density conditions. Diffusion through a resistive wall is slow relative to Alfvenic scales but much faster than resistive plasma diffusion. Loss of the initial edge pressure and current distributions leads to a narrow layer of parallel current, which drives low-n modes that may be related to peeling-dominated ELMs. These modes induce toroidal asymmetry in the conduction current, which connects the simulated plasma to the wall. Work supported by the US DOE through Grant Numbers DE-FG02-06ER54850 and DE-FC02-08ER54975.

The myosin ID pathway and left-right asymmetry in Drosophila.

PubMed

Géminard, Charles; González-Morales, Nicanor; Coutelis, Jean-Baptiste; Noselli, Stéphane

2014-06-01

Drosophila is a classical model to study body patterning, however left-right (L/R) asymmetry had remained unexplored, until recently. The discovery of the conserved myosin ID gene as a major determinant of L/R asymmetry has revealed a novel L/R pathway involving the actin cytoskeleton and the adherens junction. In this process, the HOX gene Abdominal-B plays a major role through the control of myosin ID expression and therefore symmetry breaking. In this review, we present organs and markers showing L/R asymmetry in Drosophila and discuss our current understanding of the underlying molecular genetic mechanisms. Drosophila represents a valuable model system revealing novel strategies to establish L/R asymmetry in invertebrates and providing an evolutionary perspective to the problem of laterality in bilateria. © 2014 Wiley Periodicals, Inc.

ep→epπ0 reaction studied in the Δ(1232) mass region using polarization asymmetries

NASA Astrophysics Data System (ADS)

Biselli, A.; Adams, G. S.; Amaryan, M. J.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Asryan, G.; Audit, G.; Auger, T.; Avakian, H.; Barrow, S.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Bertozzi, W.; Bianchi, N.; Boiarinov, S.; Bonner, B. E.; Bosted, P.; Bouchigny, S.; Bradford, R.; Branford, D.; Brooks, W. K.; Bueltmann, S.; Burkert, V. D.; Calarco, J. R.; Carman, D. S.; Carnahan, B.; Cetina, C.; Ciciani, L.; Cole, P. L.; Coleman, A.; Connelly, J.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J.; de Sanctis, E.; de Vita, R.; Degtyarenko, P. V.; Demirchyan, R. A.; Denizli, H.; Dennis, L. C.; Dharmawardane, K. V.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Domingo, J.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Eckhause, M.; Efremenko, Y. V.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Farhi, L.; Fatemi, R.; Feuerbach, R. J.; Ficenec, J.; Fissum, K.; Forest, T. A.; Freyberger, A.; Frolov, V.; Funsten, H.; Gaff, S. J.; Gai, M.; Gavalian, G.; Gavrilov, V. B.; Gilad, S.; Gilfoyle, G. P.; Giovanetti, K. L.; Girard, P.; Golovatch, E.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guo, L.; Gyurjyan, V.; Hanock, D.; Hardie, J.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hicks, R. S.; Holtrop, M.; Hu, J.; Hyde-Wright, C. E.; Ito, M. M.; Jenkins, D.; Joo, K.; Kelley, J. H.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kuang, Y.; Kuhn, J.; Kuhn, S. E.; Lachniet, J.; Laget, J. M.; Lawrence, D.; Leksin, G. A.; Longhi, A.; Loukachine, K.; Major, R. W.; Manak, J. J.; Marchand, C.; Matthews, S. K.; McAleer, S.; McNabb, J. W.; McCarthy, J.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Muccifora, V.; Mueller, J.; Murphy, L. Y.; Mutchler, G. S.; Napolitano, J.; Nelson, S. O.; Niculescu, G.; Niczyporuk, B.; Niyazov, R. A.; Nozar, M.; O'Brien, J. T.; O'Rielly, G. V.; Ohandjanyan, M. S.; Osipenko, M.; Park, K.; Patois, Y.; Peterson, G. A.; Philips, S.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Preedom, B. M.; Price, J. W.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rock, S.; Ronchetti, F.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabourov, K.; Salgado, C. W.; Sapunenko, V.; Sargsyan, M.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Shuvalov, S. M.; Simionatto, S.; Skabelin, A.; Smith, E. S.; Smith, L. C.; Smith, T.; Sober, D. I.; Sorrell, L.; Spraker, M.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Taiuti, M.; Taylor, S.; Tedeschi, D.; Thoma, U.; Thompson, R.; Todor, L.; Tung, T. Y.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A.; Wang, K.; Weinstein, L. B.; Weller, H.; Welsh, R.; Weygand, D. P.; Whisnant, S.; Witkowski, M.; Wolin, E.; Yegneswaran, A.; Yun, J.; Zhang, B.; Zhao, J.; Zhou, Z.

2003-09-01

Measurements of the angular distributions of target and double-spin asymmetries for the Δ+(1232) in the exclusive channel p→(e→,e'p)π0 obtained at the Jefferson Lab in the Q2 range from 0.5 to 1.5 GeV2/c2 are presented. Results of the asymmetries are compared with the unitary isobar model [D. Drechsel et al., Nucl. Phys. A645, 145 (1999)], dynamical models [T. Sato and T. S. Lee, Phys. Rev. C 54, 2660 (1996); S. S. Kamalov et al., Phys. Lett. B 27, 522 (2001)], and the effective Lagrangian theory [R. M. Davidson et al., Phys. Rev. D 43, 71 (1991)]. Sensitivity to the different models was observed, particularly in relation to the description of background terms on which the target asymmetry depends significantly.

Measurements of the Neutron Longitudinal Spin Asymmetry A1n and Flavor Decomposition in the Valence Quark Region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Flay, David J.

2014-08-01

The current data for the nucleon-virtual photon longitudinal spin asymmetry A1 on the proton and neutron have shown that the ratio of the polarized-to-unpolarized down-quarkparton distribution functions,Dd=d, tends towards -1/2 at large x, in disagreement with the perturbative QCD prediction that Dd/d approaches 1 but more in line with constituent quark models. As a part of experiment E06-014 in Hall A of Jefferson Lab, double-spin asymmetries were measured in the scattering of a longitudinally polarized electron beam of energies 4.74 and 5.89 GeV from a longitudinally and transversely polarized 3He target in the deep inelastic scattering and resonance region, allowingmore » for the extraction of the neutron asymmetry An1 and the ratios Dd/d and Du/u. We will discuss our analysis of the data and present results for A1 and g1/F1 on both 3He and the neutron, and the resulting quark ratios for the up and down quarks in the kinematic range of 0.2« less

Ear asymmetries in middle-ear, cochlear, and brainstem responses in human infants

PubMed Central

Keefe, Douglas H.; Gorga, Michael P.; Jesteadt, Walt; Smith, Lynette M.

2008-01-01

In 2004, Sininger and Cone-Wesson examined asymmetries in the signal-to-noise ratio (SNR) of otoacoustic emissions (OAE) in infants, reporting that distortion-product (DP)OAE SNR was larger in the left ear, whereas transient-evoked (TE)OAE SNR was larger in the right. They proposed that cochlear and brainstem asymmetries facilitate development of brain-hemispheric specialization for sound processing. Similarly, in 2006 Sininger and Cone-Wesson described ear asymmetries mainly favoring the right ear in infant auditory brainstem responses (ABRs). The present study analyzed 2640 infant responses to further explore these effects. Ear differences in OAE SNR, signal, and noise were evaluated separately and across frequencies (1.5, 2, 3, and 4 kHz), and ABR asymmetries were compared with cochlear asymmetries. Analyses of ear-canal reflectance and admittance showed that asymmetries in middle-ear functioning did not explain cochlear and brainstem asymmetries. Current results are consistent with earlier studies showing right-ear dominance for TEOAE and ABR. Noise levels were higher in the right ear for OAEs and ABRs, causing ear asymmetries in SNR to differ from those in signal level. No left-ear dominance for DPOAE signal was observed. These results do not support a theory that ear asymmetries in cochlear processing mimic hemispheric brain specialization for auditory processing. PMID:18345839

D meson production asymmetry, unfavored fragmentation, and consequences for prompt atmospheric neutrino production

NASA Astrophysics Data System (ADS)

Maciuła, Rafał; Szczurek, Antoni

2018-04-01

We consider unfavored light quark/antiquark to D meson fragmentation. We discuss nonperturbative effects for small transverse momenta. The asymmetry for D+ and D- production measured by the LHCb collaboration provides natural constraints on the parton (quark/antiquark) fragmentation functions. We find that already a fraction of q /q ¯→D fragmentation probability is sufficient to account for the measured asymmetry. We make predictions for similar asymmetry for neutral D mesons. Large D -meson production asymmetries are found for large xF which is related to dominance of light quark/antiquark q /q ¯→D fragmentation over the standard c →D fragmentation. As a consequence, prompt atmospheric neutrino flux at high neutrino energies can be much larger than for the conventional c →D fragmentation. The latter can constitute a sizeable background for the cosmic neutrinos claimed to be observed recently by the IceCube Observatory. Large rapidity-dependent D+/D- and D0/D¯0 asymmetries are predicted for low (√{s }=20 - 100 GeV ) energies. The q /q ¯→D fragmentation leads to enhanced production of D mesons at low energies. At √{s }=20 GeV the enhancement factor with respect to the conventional contribution is larger than a factor of five. In the considered picture the large-xF D mesons are produced dominantly via fragmentation of light quarks/antiquarks. Predictions for fixed target p + 4He collisions relevant for a fixed target LHCb experiment are presented.

Three-Dimensional Modeling of Low-Mode Asymmetries in OMEGA Cryogenic Implosions

NASA Astrophysics Data System (ADS)

Anderson, K. S.; McKenty, P. W.; Shvydky, A.; Collins, T. J. B.; Forrest, C. J.; Knauer, J. P.; Marozas, J. A.; Marshall, F. J.; Radha, P. B.; Sefkow, A. B.; Marinak, M. M.

2017-10-01

In direct-drive inertial confinement fusion implosions, long-wavelength asymmetries resulting from target offset, laser power imbalance, beam mispointing, etc. can be highly detrimental to target performance. Characterizing the effects of these asymmetry sources requires 3-D simulations performed in full-sphere geometry to accurately capture the evolution of shell perturbations and hot-spot flow. This paper will present 3-D HYDRA simulations characterizing the impact of these perturbation sources on yield and shell modulation. Various simulated observables are generated, and trends are analyzed and compared with experimental data. This material is based on work supported by the Department of Energy National Nuclear Security Administration under Award Numbers DE-NA0001944 and performed under the auspices of the LLNL under Contract No. DE-AC52-07NA27344.

Measurement of the Σ beam asymmetry for the ω photoproduction off the proton and the neutron at the GRAAL experiment

NASA Astrophysics Data System (ADS)

Vegna, V.; D'Angelo, A.; Bartalini, O.; Bellini, V.; Bocquet, J.-P.; Capogni, M.; Casano, L. E.; Castoldi, M.; Curciarello, F.; de Leo, V.; Didelez, J.-P.; di Salvo, R.; Fantini, A.; Franco, D.; Gervino, G.; Ghio, F.; Giardina, G.; Girolami, B.; Giusa, A.; Lapik, A.; Levi Sandri, P.; Lleres, A.; Mammoliti, F.; Mandaglio, G.; Manganaro, M.; Moricciani, D.; Mushkarenkov, A.; Nedorezov, V.; Randieri, C.; Rebreyend, D.; Rudnev, N.; Russo, G.; Schaerf, C.; Sperduto, M.-L.; Sutera, M.-C.; Turinge, A.; Zonta, I.; Graal Collaboration

2015-06-01

We report on new measurements of the beam asymmetry for ω photoproduction on protons and neutrons in hydrogen and deuterium targets from the GRAAL Collaboration. The beam asymmetry values are extracted from the reaction threshold (Eγ=1.1 GeV in the free nucleon kinematics) up to 1.5 GeV of incoming photon energy. For the first time both the radiative and the three-pion decay channels are simultaneously investigated on the free proton. Results from the two decay channels are in agreement, leading to the world's most precise measurements of the beam asymmetry for ω photoproduction off free protons. First experimental results on the deuteron allow the extraction of the Σ beam asymmetry on quasifree nucleons. The beam asymmetry angular distributions obtained for the free and the quasifree kinematics show the same behavior, similar to the findings in pseudoscalar meson photoproduction reactions. First results of the beam asymmetry on the quasifree neutrons are presented, showing different strengths and angular distributions from the results on the proton target.

Numerical study of the current-convective instability driven by asymmetry of detachment in inner and outer divertors

NASA Astrophysics Data System (ADS)

Stepanenko, A. A.; Krasheninnikov, S. I.

2018-01-01

One of the possible mechanisms responsible for strong radiation fluctuations observed in recent experiments with detached plasmas at ASDEX Upgrade [Potzel et al., Nucl. Fusion 54, 013001 (2014)] can be related to the onset of the current-convective instability (CCI) driven by strong asymmetry of detachment in the inner and outer divertors of the tokamak [S. Krasheninnikov and A. Smolyakov, Phys. Plasmas 23, 092505 (2016)]. In this study, we present the physical model, used to simulate the CCI, and the first numerical results of modeling of the CCI dynamics in ASDEX Upgrade-like conditions. The simulation results provide frequency spectra of turbulent divertor plasma oscillations showing reasonably good agreement with the available experimental data.

Peripheral neuropathy reduces asymmetries in inter-limb transfer in a visuo-motor task.

PubMed

Pan, Zhujun; Van Gemmert, Arend W A

2016-01-01

Asymmetry of inter-limb transfer has been associated with the specialization of the dominant and non-dominant motor system. Reductions of asymmetry have been interpreted as behavioural evidence showing a decline of hemispheric lateralization. A previous study showed that ageing did not qualitatively change the inter-limb transfer asymmetry of a visuo-motor task. The current study elaborates on these findings; it examines whether diminished somatosensory information as a result of peripheral neuropathy (PN) adversely affects inter-limb transfer asymmetry. Twenty individuals affected by PN and 20 older controls were recruited and divided equally across two groups. One group trained a visuo-motor task with the right hand while the other group trained it with the left hand. Performance (initial direction error) of the untrained hand before and after training was collected to determine learning effects from inter-limb transfer. Similar to previous studies, the current study showed asymmetric inter-limb transfer in older controls. In contrast, PN showed inter-limb transfer in both directions indicating that PN reduces inter-limb transfer asymmetry. Increased bilateral hemispheric recruitment is suggested to be responsible for this reduced asymmetry which may compensate for deteriorated tactile and/or proprioceptive inputs in PN. Two possible hypotheses are discussed explaining the relationship between declined somatosensory information and increases in bilateral hemispheric recruitment.

First measurement of the Sivers asymmetry for gluons using SIDIS data

NASA Astrophysics Data System (ADS)

Adolph, C.; Aghasyan, M.; Akhunzyanov, R.; Alexeev, M. G.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anfimov, N. V.; Anosov, V.; Antoshkin, A.; Augsten, K.; Augustyniak, W.; Austregesilo, A.; Azevedo, C. D. R.; Badełek, B.; Balestra, F.; Ball, M.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bodlak, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Chang, W.-C.; Chatterjee, C.; Chiosso, M.; Choi, I.; Chung, S.-U.; Cicuttin, A.; Crespo, M. L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O. Yu.; Dhara, L.; Donskov, S. V.; Doshita, N.; Dreisbach, Ch.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P. D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger, M.; Fischer, H.; Franco, C.; Du Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Giarra, J.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grosse Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; Hahne, D.; Hamar, G.; von Harrach, D.; Heinsius, F. H.; Heitz, R.; Herrmann, F.; Horikawa, N.; D'Hose, N.; Hsieh, C.-Y.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jary, V.; Joosten, R.; Jörg, P.; Kabuß, E.; Kerbizi, A.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O. M.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kulinich, Y.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lian, Y.-S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G. K.; Marianski, B.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G. V.; Meyer, M.; Meyer, W.; Mikhailov, Yu. V.; Mikhasenko, M.; Mitrofanov, E.; Mitrofanov, N.; Miyachi, Y.; Nagaytsev, A.; Nerling, F.; Neyret, D.; Nový, J.; Nowak, W.-D.; Nukazuka, G.; Nunes, A. S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Pierre, N.; Platchkov, S.; Pochodzalla, J.; Polyakov, V. A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Roskot, M.; Rogacheva, N. S.; Ryabchikov, D. I.; Rybnikov, A.; Rychter, A.; Salac, R.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sawada, T.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schönning, K.; Seder, E.; Selyunin, A.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Smolik, J.; Srnka, A.; Steffen, D.; Stolarski, M.; Subrt, O.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Tasevsky, M.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Thiel, A.; Tosello, F.; Tskhay, V.; Uhl, S.; Vauth, A.; Veloso, J.; Virius, M.; Vondra, J.; Wallner, S.; Weisrock, T.; Wilfert, M.; Ter Wolbeek, J.; Zaremba, K.; Zavada, P.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.; Zink, A.; Compass Collaboration

2017-09-01

The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons. For quarks, it was studied in previous measurements of the azimuthal asymmetry of hadrons produced in semi-inclusive deep inelastic scattering of leptons off transversely polarised nucleon targets, and it was found to be non-zero. In this letter the evaluation of the Sivers asymmetry for gluons is presented. The contribution of the photon-gluon fusion subprocess is enhanced by requiring two high transverse-momentum hadrons. The analysis method is based on a Monte Carlo simulation that includes three hard processes: photon-gluon fusion, QCD Compton scattering and the leading-order virtual-photon absorption process. The Sivers asymmetries of the three processes are simultaneously extracted using the LEPTO event generator and a neural network approach. The method is applied to samples of events containing at least two hadrons with large transverse momentum from the COMPASS data taken with a 160 GeV/c muon beam scattered off transversely polarised deuterons and protons. With a significance of about two standard deviations, a negative value is obtained for the gluon Sivers asymmetry. The result of a similar analysis for a Collins-like asymmetry for gluons is consistent with zero.

Just noticeable differences of open quotient and asymmetry coefficient in singing voice.

PubMed

Henrich, Nathalie; Sundin, Gunilla; Ambroise, Daniel; d'Alessandro, Christophe; Castellengo, Michèle; Doval, Boris

2003-12-01

This study aims to explore the perceptual relevance of the variations of glottal flow parameters and to what extent a small variation can be detected. Just Noticeable Differences (JNDs) have been measured for three values of open quotient (0.4, 0.6, and 0.8) and two values of asymmetry coefficient (2/3 and 0.8), and the effect of changes of vowel, pitch, vibrato, and amplitude parameters has been tested. Two main groups of subjects have been analyzed: a group of 20 untrained subjects and a group of 10 trained subjects. The results show that the JND for open quotient is highly dependent on the target value: an increase of the JND is noticed when the open quotient target value is increased. The relative JND is constant: deltaOq/Oq = 14% for the untrained and 10% for the trained. In the same way, the JND for asymmetry coefficient is also slightly dependent on the target value--an increase of the asymmetry coefficient value leads to a decrease of the JND. The results show that there is no effect from the selected vowel or frequency (two values have been tested), but that the addition of a vibrato has a small effect on the JND of open quotient. The choice of an amplitude parameter also has a great effect on the JND of open quotient.

Focus on flaviviruses: current and future drug targets.

PubMed

Geiss, Brian J; Stahla, Hillary; Hannah, Amanda M; Gari, Amanda M; Keenan, Susan M

2009-05-01

Infection by mosquito-borne flaviviruses (family Flaviviridae) is increasing in prevalence worldwide. The vast global, social and economic impact due to the morbidity and mortality associated with the diseases caused by these viruses necessitates therapeutic intervention. There is currently no effective clinical treatment for any flaviviral infection. Therefore, there is a great need for the identification of novel inhibitors to target the virus life cycle. In this article, we discuss structural and nonstructural viral proteins that are the focus of current target validation and drug discovery efforts. Both inhibition of essential enzymatic activities and disruption of necessary protein–protein interactions are considered. In addition, we address promising new targets for future research. As our molecular and biochemical understanding of the flavivirus life cycle increases, the number of targets for antiviral therapeutic discovery grows and the possibility for novel drug discovery continues to strengthen.

Heritabilities of Directional Asymmetry in the Fore- and Hindlimbs of Rabbit Fetuses

PubMed Central

Breno, Matteo; Bots, Jessica; Van Dongen, Stefan

2013-01-01

Directional asymmetry (DA), where at the population level symmetry differs from zero, has been reported in a wide range of traits and taxa, even for traits in which symmetry is expected to be the target of selection such as limbs or wings. In invertebrates, DA has been suggested to be non-adaptive. In vertebrates, there has been a wealth of research linking morphological asymmetry to behavioural lateralisation. On the other hand, the prenatal expression of DA and evidences for quantitative genetic variation for asymmetry may suggest it is not solely induced by differences in mechanic loading between sides. We estimate quantitative genetic variation of fetal limb asymmetry in a large dataset of rabbits. Our results showed a low but highly significant level of DA that is partially under genetic control for all traits, with forelimbs displaying higher levels of asymmetry. Genetic correlations were positive within limbs, but negative across bones of fore and hind limbs. Environmental correlations were positive for all, but smaller across fore and hind limbs. We discuss our results in light of the existence and maintenance of DA in locomotory traits. PMID:24130770

Alpha Asymmetry in Infants at Risk for Autism Spectrum Disorders

ERIC Educational Resources Information Center

Gabard-Durnam, Laurel; Tierney, Adrienne L.; Vogel-Farley, Vanessa; Tager-Flusberg, Helen; Nelson, Charles A.

2015-01-01

An emerging focus of research on autism spectrum disorder (ASD) targets the identification of early-developing ASD endophenotypes using infant siblings of affected children. One potential neural endophenotype is resting frontal electroencephalogram (EEG) alpha asymmetry, a metric of hemispheric organization. Here, we examined the development of…

Animal left-right asymmetry.

PubMed

Blum, Martin; Ott, Tim

2018-04-02

Symmetry is appealing, be it in architecture, art or facial expression, where symmetry is a key feature to finding someone attractive or not. Yet, asymmetries are widespread in nature, not as an erroneous deviation from the norm but as a way to adapt to the prevailing environmental conditions at a time. Asymmetries in many cases are actively selected for: they might well have increased the evolutionary fitness of a species. Even many single-celled organisms are built asymmetrically, such as the pear-shaped ciliate Paramecium, which may depend on its asymmetry to navigate towards the oxygen-richer surface of turbid waters, at least based on modeling. Everybody knows the lobster with its asymmetric pair of claws, the large crusher usually on the left and the smaller cutter on the right. Snail shells coil asymmetrically, as do the organs they house. Organ asymmetries are found throughout the animal kingdom, referring to asymmetric positioning, asymmetric morphology or both, with the vertebrate heart being an example for the latter. Functional asymmetries, such as that of the human brain with its localization of the language center in one hemisphere, add to the complexity of organ asymmetries and presumably played a decisive role for sociocultural evolution. The evolutionary origin of organ asymmetries may have been a longer than body length gut, which allows efficient retrieval of nutrients, and the need to stow a long gut in the body cavity in an orderly manner that ensures optimal functioning. Vertebrate organ asymmetries (situs solitus) are quite sophisticated: in humans, the apex of the asymmetrically built heart points to the left; the lung in turn, due to space restrictions, has fewer lobes on the left than on the right side (two versus three in humans), stomach and spleen are found on the left, the liver on the right, and small and large intestine coil in a chiral manner (Figure 1A). In very rare cases (1:10,000), the organ situs is inverted (situs inversus

Prefrontal Asymmetry and Parent-Rated Temperament in Infants

PubMed Central

LoBue, Vanessa; Coan, James A.; Thrasher, Cat; DeLoache, Judy S.

2011-01-01

Indicators of temperament appear early in infancy and remain relatively stable over time. Despite a great deal of interest in biological indices of temperament, most studies of infant temperament rely on parental reports or behavioral tasks. Thus, the extent to which commonly used temperament measures relate to potential biological indicators of infant temperament is still relatively unknown. The current experiment examines the relationship between a common parental report measure of temperament – the Infant Behavior Questionnaire – Revised (IBQ-R) – and measures of frontal EEG asymmetry in infants. We examined associations between the subscales of the IBQ-R and frontal EEG asymmetry scores recorded during a combined series of neutral attentional and putatively emotional recording conditions in infants between 7 and 9 months of age. We predicted that approach-related subscales of the IBQ-R (e.g., Approach, Soothability) would be related to greater left prefrontal asymmetry, while withdrawal-related subscales (e.g., Distress to Limitations, Fear, Falling Reactivity, Perceptual Sensitivity) would be related to greater right prefrontal asymmetry. In the mid- and lateral-frontal regions, Approach, Distress to Limitations, Fear, Soothability, and Perceptual Sensitivity were generally associated with greater left frontal activation (rs≥.23, ps<0.05), while only Falling Reactivity was associated with greater right frontal activation (rs≤−.44, ps<0.05). Results suggest that variability in frontal EEG asymmetry is robustly associated with parental report measures of temperament in infancy. PMID:21829482

Salient features of the ciliated organ of asymmetry

PubMed Central

Amack, Jeffrey D.

2014-01-01

Many internal organs develop distinct left and right sides that are essential for their functions. In several vertebrate embryos, motile cilia generate an asymmetric fluid flow that plays an important role in establishing left-right (LR) signaling cascades. These ‘LR cilia’ are found in the ventral node and posterior notochordal plate in mammals, the gastrocoel roof plate in amphibians and Kupffer’s vesicle in teleost fish. I consider these transient ciliated structures as the ‘organ of asymmetry’ that directs LR patterning of the developing embryo. Variations in size and morphology of the organ of asymmetry in different vertebrate species have raised questions regarding the fundamental features that are required for LR determination. Here, I review current models for how LR asymmetry is established in vertebrates, discuss the cellular architecture of the ciliated organ of asymmetry and then propose key features of this organ that are critical for orienting the LR body axis. PMID:24481178

Load Asymmetry Observed During Orion Main Parachute Inflation

NASA Technical Reports Server (NTRS)

Morris, Aaron L.; Taylor, Thomas; Olson, Leah

2011-01-01

The Crew Exploration Vehicle Parachute Assembly System (CPAS) has flight tested the first two generations of the Orion parachute program. Three of the second generation tests instrumented the dispersion bridles of the Main parachute with a Tension Measuring System. The goal of this load measurement was to better understand load asymmetry during the inflation process of a cluster of Main parachutes. The CPAS Main parachutes exhibit inflations that are much less symmetric than current parachute literature and design guides would indicate. This paper will examine loads data gathered on three cluster tests, quantify the degree of asymmetry observed, and contrast the results with published design guides. Additionally, the measured loads data will be correlated with videos of the parachute inflation to make inferences about the shape of the parachute and the relative load asymmetry. The goal of this inquiry and test program is to open a dialogue regarding asymmetrical parachute inflation load factors.

Quantifying asymmetry: ratios and alternatives.

PubMed

Franks, Erin M; Cabo, Luis L

2014-08-01

Traditionally, the study of metric skeletal asymmetry has relied largely on univariate analyses, utilizing ratio transformations when the goal is comparing asymmetries in skeletal elements or populations of dissimilar dimensions. Under this approach, raw asymmetries are divided by a size marker, such as a bilateral average, in an attempt to produce size-free asymmetry indices. Henceforth, this will be referred to as "controlling for size" (see Smith: Curr Anthropol 46 (2005) 249-273). Ratios obtained in this manner often require further transformations to interpret the meaning and sources of asymmetry. This model frequently ignores the fundamental assumption of ratios: the relationship between the variables entered in the ratio must be isometric. Violations of this assumption can obscure existing asymmetries and render spurious results. In this study, we examined the performance of the classic indices in detecting and portraying the asymmetry patterns in four human appendicular bones and explored potential methodological alternatives. Examination of the ratio model revealed that it does not fulfill its intended goals in the bones examined, as the numerator and denominator are independent in all cases. The ratios also introduced strong biases in the comparisons between different elements and variables, generating spurious asymmetry patterns. Multivariate analyses strongly suggest that any transformation to control for overall size or variable range must be conducted before, rather than after, calculating the asymmetries. A combination of exploratory multivariate techniques, such as Principal Components Analysis, and confirmatory linear methods, such as regression and analysis of covariance, appear as a promising and powerful alternative to the use of ratios. © 2014 Wiley Periodicals, Inc.

The asymmetry of the heliospheric current sheet during solar cycle 23: The last dance of the bashful ballerina?

NASA Astrophysics Data System (ADS)

Mursula, K.; Virtanen, I. I.

2010-05-01

The heliospheric magnetic field has long been hemispherically asymmetric so that the field in the northern hemisphere is weaker and the area larger than in the south. This asymmetry, also called the bashful ballerina, has existed during three-year intervals in the late declining to minimum phase of solar cycles 16-22. We study here the HMF and its hemispheric asymmetry during solar cycle 23. We find that the latitudinal ordering of HMF sectors at low latitudes is exceptional in SC 23: the normal latitudinal variation was not established in the south by Spring 2009, implying that the Rosenberg-Coleman rule is abnormally delayed or broken during this cycle. Comparing the radial field at 1AU and at the coronal source surface footpoint, we show that the HCS was southward shifted even in SC 23 but the shift is considerably smaller than in earlier cycles. We also study the HMF observations during the third perihelion pass of the Ulysses probe in 2007, and find that the northern field was some 0.2 nT stronger than the southern field and that the whole HCS region was clearly shifted southward by about 2°-5°. Accordingly, the north-south asymmetry existed even in SC 23 but was largely masked out in ecliptic observations due to the exceptionally weak polar fields, leading to an abnormally large HCS tilt angle and a wide equatorial belt region. We also note that historical evidence at the ecliptic suggests a connection between solar dipole strength and the size of north-south asymmetry observed there. Based on this, one can predict that, after the present period of weak solar activity started in SC 23, the hemispheric asymmetry will grow again with increasing activity, but the orientation of the asymmetry will be opposite. Thus, after SC 23, the solar ballerina will not be bashful for some 100-150 years.

Asymmetry in the epithalamus of vertebrates

PubMed Central

L. CONCHA, MIGUEL; W. WILSON, STEPHEN

2001-01-01

The epithalamus is a major subdivision of the diencephalon constituted by the habenular nuclei and pineal complex. Structural asymmetries in this region are widespread amongst vertebrates and involve differences in size, neuronal organisation, neurochemistry and connectivity. In species that possess a photoreceptive parapineal organ, this structure projects asymmetrically to the left habenula, and in teleosts it is also situated on the left side of the brain. Asymmetries in size between the left and right sides of the habenula are often associated with asymmetries in neuronal organisation, although these two types of asymmetry follow different evolutionary courses. While the former is more conspicuous in fishes (with the exception of teleosts), asymmetries in neuronal organisation are more robust in amphibia and reptiles. Connectivity of the parapineal organ with the left habenula is not always coupled with asymmetries in habenular size and/or neuronal organisation suggesting that, at least in some species, assignment of parapineal and habenular asymmetries may be independent events. The evolutionary origins of epithalamic structures are uncertain but asymmetry in this region is likely to have existed at the origin of the vertebrate, perhaps even the chordate, lineage. In at least some extant vertebrate species, epithalamic asymmetries are established early in development, suggesting a genetic regulation of asymmetry. In some cases, epigenetic factors such as hormones also influence the development of sexually dimorphic habenular asymmetries. Although the genetic and developmental mechanisms by which neuroanatomical asymmetries are established remain obscure, some clues regarding the mechanisms underlying laterality decisions have recently come from studies in zebrafish. The Nodal signalling pathway regulates laterality by biasing an otherwise stochastic laterality decision to the left side of the epithalamus. This genetic mechanism ensures a consistency of

Asymmetry and coherence weight of quantum states

NASA Astrophysics Data System (ADS)

Bu, Kaifeng; Anand, Namit; Singh, Uttam

2018-03-01

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

Attentional reorienting triggers spatial asymmetries in a search task with cross-modal spatial cueing

PubMed Central

Paladini, Rebecca E.; Diana, Lorenzo; Zito, Giuseppe A.; Nyffeler, Thomas; Wyss, Patric; Mosimann, Urs P.; Müri, René M.; Nef, Tobias

2018-01-01

Cross-modal spatial cueing can affect performance in a visual search task. For example, search performance improves if a visual target and an auditory cue originate from the same spatial location, and it deteriorates if they originate from different locations. Moreover, it has recently been postulated that multisensory settings, i.e., experimental settings, in which critical stimuli are concurrently presented in different sensory modalities (e.g., visual and auditory), may trigger asymmetries in visuospatial attention. Thereby, a facilitation has been observed for visual stimuli presented in the right compared to the left visual space. However, it remains unclear whether auditory cueing of attention differentially affects search performance in the left and the right hemifields in audio-visual search tasks. The present study investigated whether spatial asymmetries would occur in a search task with cross-modal spatial cueing. Participants completed a visual search task that contained no auditory cues (i.e., unimodal visual condition), spatially congruent, spatially incongruent, and spatially non-informative auditory cues. To further assess participants’ accuracy in localising the auditory cues, a unimodal auditory spatial localisation task was also administered. The results demonstrated no left/right asymmetries in the unimodal visual search condition. Both an additional incongruent, as well as a spatially non-informative, auditory cue resulted in lateral asymmetries. Thereby, search times were increased for targets presented in the left compared to the right hemifield. No such spatial asymmetry was observed in the congruent condition. However, participants’ performance in the congruent condition was modulated by their tone localisation accuracy. The findings of the present study demonstrate that spatial asymmetries in multisensory processing depend on the validity of the cross-modal cues, and occur under specific attentional conditions, i.e., when visual

Final state interactions and the extraction of neutron single spin asymmetries from semi-inclusive deep-inelastic scattering by a transversely polarized 3He target

NASA Astrophysics Data System (ADS)

Del Dotto, A.; Kaptari, L. P.; Pace, E.; Salmè, G.; Scopetta, S.

2017-12-01

The semi-inclusive deep-inelastic electron scattering off transversely polarized 3He, i.e., the process e +3He ⃗→e'+h +X , with h being a detected fast hadron, is studied beyond the plane-wave impulse approximation. To this end, a distorted spin-dependent spectral function of a nucleon inside an A =3 nucleus is actually evaluated through a generalized eikonal approximation, in order to take into account the final state interactions between the hadronizing system and the (A -1 ) nucleon spectator one. Our realistic description of both nuclear target and final state is a substantial step forward for achieving a reliable extraction of the Sivers and Collins single spin asymmetries of the free neutron. To illustrate how and to what extent the model dependence due to the treatment of the nuclear effects is under control, we apply our approach to the extraction procedure of the neutron single spin asymmetries from those measured for 3He for values of the kinematical variables relevant both for forthcoming experiments at Jefferson Laboratory and, with an exploratory purpose, for the future Electron Ion Collider.

Measurement of the β-asymmetry parameter of Cu67 in search for tensor-type currents in the weak interaction

NASA Astrophysics Data System (ADS)

Soti, G.; Wauters, F.; Breitenfeldt, M.; Finlay, P.; Herzog, P.; Knecht, A.; Köster, U.; Kraev, I. S.; Porobic, T.; Prashanth, P. N.; Towner, I. S.; Tramm, C.; Zákoucký, D.; Severijns, N.

2014-09-01

Background: Precision measurements at low energy search for physics beyond the standard model in a way complementary to searches for new particles at colliders. In the weak sector the most general β-decay Hamiltonian contains, besides vector and axial-vector terms, also scalar, tensor, and pseudoscalar terms. Current limits on the scalar and tensor coupling constants from neutron and nuclear β decay are on the level of several percent. Purpose: Extracting new information on tensor coupling constants by measuring the β-asymmetry parameter in the pure Gamow-Teller decay of Cu67, thereby testing the V-A structure of the weak interaction. Method: An iron sample foil into which the radioactive nuclei were implanted was cooled down to mK temperatures in a 3He-4He dilution refrigerator. An external magnetic field of 0.1 T, in combination with the internal hyperfine magnetic field, oriented the nuclei. The anisotropic β radiation was observed with planar high-purity germanium detectors operating at a temperature of about 10 K. An on-line measurement of the β asymmetry of Cu68 was performed as well for normalization purposes. Systematic effects were investigated using geant4 simulations. Results: The experimental value, Ã=0.587(14), is in agreement with the standard model value of 0.5991(2) and is interpreted in terms of physics beyond the standard model. The limits obtained on possible tensor-type charged currents in the weak interaction Hamiltonian are -0.045<(CT+CT')/CA<0.159 (90% C.L.). Conclusions: The obtained limits are comparable to limits from other correlation measurements in nuclear β decay and contribute to further constraining tensor coupling constants.

A Measurement of the Parity-Violating Asymmetry in Aluminum and its Contribution to a Measurement of the Proton's Weak Charge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Magee, Joshua Allen

2016-05-01

The Q_weak experiment, which ran at the Thomas Jefferson National Accelerator Facility, made a precision measurement of the proton's weak charge, Q^p_W. The weak charge is extracted via a measurement of the parity-violating asymmetry in elastic electron-proton scattering from hydrogen at low momentum transfer (Q^2=0.025 GeV^2). This result is directly related to the electroweak mixing angle, sin^2(Theta_W), a fundamental parameter in the Standard Model of particle physics. This provides a precision test sensitive to new, as yet unknown, fundamental physics. This dissertation focuses on two central corrections to the Q_weak measurement: the target window contribution and sub-percent determination of themore » electron beam polarization. The aluminum target windows contribute approximately 30% of the measured asymmetry. Removal of this background requires precise measurements of both the elastic electron-aluminum scattering rate and its parity-violating asymmetry. The results reported here are the most precise measurement of the Q_weak target dilution and asymmetry to date. The parity-violating asymmetry for the aluminum alloy was found to be 1.6174 +/- 0.0704 (stat.) +/- 0.0113 (sys.) parts-per-million. The first sub-percent precision polarization measurements made from the Hall C Moller polarimeter are also reported, with systematic uncertainties of 0.84%.« less

Qweak Data Analysis for Target Modeling Using Computational Fluid Dynamics

NASA Astrophysics Data System (ADS)

Moore, Michael; Covrig, Silviu

2015-04-01

The 2.5 kW liquid hydrogen (LH2) target used in the Qweak parity violation experiment is the highest power LH2 target in the world and the first to be designed with Computational Fluid Dynamics (CFD) at Jefferson Lab. The Qweak experiment determined the weak charge of the proton by measuring the parity-violating elastic scattering asymmetry of longitudinally polarized electrons from unpolarized liquid hydrogen at small momentum transfer (Q2 = 0 . 025 GeV2). This target met the design goals of < 1 % luminosity reduction and < 5 % contribution to the total asymmetry width (the Qweak target achieved 2 % or 55 ppm). State of the art time dependent CFD simulations are being developed to improve the predictions of target noise on the time scale of the electron beam helicity period. These predictions will be bench-marked with the Qweak target data. This work is an essential ingredient in future designs of very high power low noise targets like MOLLER (5 kW, target noise asymmetry contribution < 25 ppm) and MESA (4.5 kW).

Design and performance of the spin asymmetries of the nucleon experiment

DOE PAGES

Maxwell, J. D.; Armstrong, W. R.; Choi, S.; ...

2018-03-01

The Spin Asymmetries of the Nucleon Experiment (SANE) performed inclusive, double-polarized electron scattering measurements of the proton at the Continuous Electron Beam Facility at Jefferson Lab. A novel detector array observed scattered electrons of four-momentum transfer 2.5 < Q 2 < 6.5 GeV 2 and Bjorken scaling 0.3 < x < 0.8 from initial beam energies of 4.7 and 5.9 GeV. Employing a polarized proton target which could be rotated with respect to the incident electron beam, both parallel and near perpendicular spin asymmetries were measured, allowing model-independent access to transverse polarization observables A 1, A 2, g 1, gmore » 2 and moment d 2 of the proton. This article summarizes the operation and performance of the polarized target, polarized electron beam, and novel detector systems used during the course of the experiment, and describes analysis techniques utilized to access the physics observables of interest.« less

Design and performance of the spin asymmetries of the nucleon experiment

NASA Astrophysics Data System (ADS)

Maxwell, J. D.; Armstrong, W. R.; Choi, S.; Jones, M. K.; Kang, H.; Liyanage, A.; Meziani, Z.-E.; Mulholland, J.; Ndukum, L.; Rondón, O. A.; Ahmidouch, A.; Albayrak, I.; Asaturyan, A.; Ates, O.; Baghdasaryan, H.; Boeglin, W.; Bosted, P.; Brash, E.; Brock, J.; Butuceanu, C.; Bychkov, M.; Carlin, C.; Carter, P.; Chen, C.; Chen, J.-P.; Christy, M. E.; Covrig, S.; Crabb, D.; Danagoulian, S.; Daniel, A.; Davidenko, A. M.; Davis, B.; Day, D.; Deconinck, W.; Deur, A.; Dunne, J.; Dutta, D.; El Fassi, L.; Elaasar, M.; Ellis, C.; Ent, R.; Flay, D.; Frlez, E.; Gaskell, D.; Geagla, O.; German, J.; Gilman, R.; Gogami, T.; Gomez, J.; Goncharenko, Y. M.; Hashimoto, O.; Higinbotham, D. W.; Horn, T.; Huber, G. M.; Jones, M.; Kalantarians, N.; Kang, H. K.; Kawama, D.; Keith, C.; Keppel, C.; Khandaker, M.; Kim, Y.; King, P. M.; Kohl, M.; Kovacs, K.; Kubarovsky, V.; Li, Y.; Liyanage, N.; Luo, W.; Mamyan, V.; Markowitz, P.; Maruta, T.; Meekins, D.; Melnik, Y. M.; Mkrtchyan, A.; Mkrtchyan, H.; Mochalov, V. V.; Monaghan, P.; Narayan, A.; Nakamura, S. N.; Nuruzzaman; Pentchev, L.; Pocanic, D.; Posik, M.; Puckett, A.; Qiu, X.; Reinhold, J.; Riordan, S.; Roche, J.; Sawatzky, B.; Shabestari, M.; Slifer, K.; Smith, G.; Soloviev, L.; Solvignon, P.; Tadevosyan, V.; Tang, L.; Vasiliev, A. N.; Veilleux, M.; Walton, T.; Wesselmann, F.; Wood, S. A.; Yao, H.; Ye, Z.; Zhu, L.

2018-03-01

The Spin Asymmetries of the Nucleon Experiment (SANE) performed inclusive, double-polarized electron scattering measurements of the proton at the Continuous Electron Beam Accelerator Facility at Jefferson Lab. A novel detector array observed scattered electrons of four-momentum transfer 2 . 5 target whose magnetic field direction could be rotated with respect to the incident electron beam, both parallel and near perpendicular spin asymmetries were measured, allowing model-independent access to transverse polarization observables A1, A2, g1, g2 and moment d2 of the proton. This document summarizes the operation and performance of the polarized target, polarized electron beam, and novel detector systems used during the course of the experiment, and describes analysis techniques utilized to access the physics observables of interest.

Design and performance of the spin asymmetries of the nucleon experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maxwell, J. D.; Armstrong, W. R.; Choi, S.

The Spin Asymmetries of the Nucleon Experiment (SANE) performed inclusive, double-polarized electron scattering measurements of the proton at the Continuous Electron Beam Facility at Jefferson Lab. A novel detector array observed scattered electrons of four-momentum transfer 2.5 < Q 2 < 6.5 GeV 2 and Bjorken scaling 0.3 < x < 0.8 from initial beam energies of 4.7 and 5.9 GeV. Employing a polarized proton target which could be rotated with respect to the incident electron beam, both parallel and near perpendicular spin asymmetries were measured, allowing model-independent access to transverse polarization observables A 1, A 2, g 1, gmore » 2 and moment d 2 of the proton. This article summarizes the operation and performance of the polarized target, polarized electron beam, and novel detector systems used during the course of the experiment, and describes analysis techniques utilized to access the physics observables of interest.« less

Precise measurements of beam spin asymmetries in semi-inclusive π0 production

NASA Astrophysics Data System (ADS)

Aghasyan, M.; Avakian, H.; Rossi, P.; De Sanctis, E.; Hasch, D.; Mirazita, M.; Adikaram, D.; Amaryan, M. J.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Branford, D.; Briscoe, W. J.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Chandavar, S.; Cole, P. L.; Collins, P.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Daniel, A.; Dashyan, N.; De Vita, R.; Deur, A.; Dey, B.; Dickson, R.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dupre, R.; Egiyan, H.; El Alaoui, A.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fradi, A.; Gabrielyan, M. Y.; Garçon, M.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Graham, L.; Griffioen, K. A.; Guegan, B.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hanretty, C.; Hicks, K.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Isupov, E. L.; Jawalkar, S. S.; Jenkins, D.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Kuznetsov, V.; Kvaltine, N. D.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McAndrew, J.; McKinnon, B.; Meyer, C. A.; Micherdzinska, A. M.; Mokeev, V.; Moreno, B.; Moutarde, H.; Munevar, E.; Nadel-Turonski, P.; Ni, A.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Pappalardo, L.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Pereira, S. Anefalos; Phelps, E.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Rimal, D.; Ripani, M.; Rosner, G.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Stepanyan, S. S.; Stepanyan, S.; Stoler, P.; Strakovsky, I.; Strauch, S.; Taiuti, M.; Tang, W.; Taylor, C. E.; Tkachenko, S.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Watts, D.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z. W.

2011-10-01

We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial sinϕh amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle ϕh of the produced neutral pion. The dependence of this amplitude on Bjorken x and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations.

Precise Measurements of Beam Spin Asymmetries in Semi-Inclusive π 0 production

DOE PAGES

Aghasyan, M.; Avakian, H.; Rossi, P.; ...

2011-10-01

We present studies of single-spin asymmetries for neutral pion electroproduction in semi-inclusive deep-inelastic scattering of 5.776 GeV polarized electrons from an unpolarized hydrogen target, using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility. A substantial sin Φ h amplitude has been measured in the distribution of the cross section asymmetry as a function of the azimuthal angle Φ h of the produced neutral pion. The dependence of this amplitude on Bjorken x and on the pion transverse momentum is extracted with significantly higher precision than previous data and is compared to model calculations.

Hemispheric asymmetry of liking for representational and abstract paintings.

PubMed

Nadal, Marcos; Schiavi, Susanna; Cattaneo, Zaira

2017-10-13

Although the neural correlates of the appreciation of aesthetic qualities have been the target of much research in the past decade, few experiments have explored the hemispheric asymmetries in underlying processes. In this study, we used a divided visual field paradigm to test for hemispheric asymmetries in men and women's preference for abstract and representational artworks. Both male and female participants liked representational paintings more when presented in the right visual field, whereas preference for abstract paintings was unaffected by presentation hemifield. We hypothesize that this result reflects a facilitation of the sort of visual processes relevant to laypeople's liking for art-specifically, local processing of highly informative object features-when artworks are presented in the right visual field, given the left hemisphere's advantage in processing such features.

Raytracing and Direct-Drive Targets

NASA Astrophysics Data System (ADS)

Schmitt, Andrew J.; Bates, Jason; Fyfe, David; Eimerl, David

2013-10-01

Accurate simulation of the effects of laser imprinting and drive asymmetries in directly driven targets requires the ability to distinguish between raytrace noise and the intensity structure produced by the spatial and temporal incoherence of optical smoothing. We have developed and implemented a smoother raytrace algorithm for our mpi-parallel radiation hydrodynamics code, FAST3D. The underlying approach is to connect the rays into either sheets (in 2D) or volume-enclosing chunks (in 3D) so that the absorbed energy distribution continuously covers the propagation area illuminated by the laser. We will describe the status and show the different scalings encountered in 2D and 3D problems as the computational size, parallelization strategy, and number of rays is varied. Finally, we show results using the method in current NIKE experimental target simulations and in proposed symmetric and polar direct-drive target designs. Supported by US DoE/NNSA.

Probing Flavor Asymmetry of Anti-quarks in the Proton by Drell-Yan Experiment SeaQuest

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyasaka, Shou

started in 2013. The SeaQuest spectrometer is designed to detect dimuon from the Drell-Yan process. It consists of targets, two di-pole magnets, and four tracking detector groups. The third tracking detector group has two drift chambers. One was newly fabricated in Japan by the Japanese group in SeaQuest collaboration and was shipped to Fermilab. The other one was constructed by SeaQuest collaborator in Fermilab under the initiative of the Japanese group. I worked on the construction and installation of the detectors, data taking and data analysis in SeaQuest. I extracted the avor asymmetry as a function of Bjorken x using the SeaQuest data for the rst time. This thesis shows the results using a part of data taken in 2014 and 2015. The asymmetry was extracted for much wider Bjorken x region than the previous experiment. The measured Bjorken x range covers up to 0.58. The result shows that the ratio of d=u is always higher than 1 at 0:1 < x < 0:45, in contrast to the E866 result. For 0:45 < x < 0:58, the result shows that the ratio is close to unity. Predictions made by current PDF parameterizations are in agreement with the present result. Also, a prediction obtained by one of the non-perturbative models, pion-cloud model, is closer to the SeaQuest result than the E866 result. This result of d=u asymmetry at the wide Bjorken x region, 0:1 < x < 0:58, is very important information to understand the inner structure of the proton and the origin of the sea quarks in the proton.« less

Beam Normal Single Spin Asymmetry in Forward Angle Inelastic Electron-Proton Scattering using the Q-Weak Apparatus

DOE Office of Scientific and Technical Information (OSTI.GOV)

., Nuruzzaman

2014-12-01

The Q-weak experiment in Hall-C at the Thomas Jefferson National Accelerator Facility has made the first direct measurement of the weak charge of the proton through the precision measurement of the parity-violating asymmetry in elastic electron-proton scattering at low momentum transfer. There is also a parity conserving Beam Normal Single Spin Asymmetry or transverse asymmetry (B_n) on H_2 with a sin(phi)-like dependence due to two-photon exchange. If the size of elastic B_n is a few ppm, then a few percent residual transverse polarization in the beam, combined with small broken azimuthal symmetries in the detector, would require a few ppbmore » correction to the Q-weak data. As part of a program of B_n background studies, we made the first measurement of B_n in the N-to-Delta(1232) transition using the Q-weak apparatus. The final transverse asymmetry, corrected for backgrounds and beam polarization, was found to be B_n = 42.82 ± 2.45 (stat) ± 16.07 (sys) ppm at beam energy E_beam = 1.155 GeV, scattering angle theta = 8.3 deg, and missing mass W = 1.2 GeV. B_n from electron-nucleon scattering is a unique tool to study the gamma^* Delta Delta form factors, and this measurement will help to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process. To help correct false asymmetries from beam noise, a beam modulation system was implemented to induce small position, angle, and energy changes at the target to characterize detector response to the beam jitter. Two air-core dipoles separated by ~10 m were pulsed at a time to produce position and angle changes at the target, for virtually any tune of the beamline. The beam energy was modulated using an SRF cavity. The hardware and associated control instrumentation will be described in this dissertation. Preliminary detector sensitivities were extracted which helped to reduce the width of the measured asymmetry. The beam

Intrachromosomal karyotype asymmetry in Orchidaceae.

PubMed

Medeiros-Neto, Enoque; Nollet, Felipe; Moraes, Ana Paula; Felix, Leonardo P

2017-01-01

The asymmetry indexes have helped cytotaxonomists to interpret and classify plant karyotypes for species delimitation efforts. However, there is no consensus about the best method to calculate the intrachromosomal asymmetry. The present study aimed to compare different intrachromosomal asymmetry indexes in order to indicate which are more efficient for the estimation of asymmetry in different groups of orchids. Besides, we aimed to compare our results with the Orchidaceae phylogenetic proposal to test the hypothesis of Stebbins (1971). Through a literature review, karyotypes were selected and analyzed comparatively with ideal karyotypes in a cluster analysis. All karyotypes showed some level of interchromosomal asymmetry, ranging from slightly asymmetric to moderately asymmetric. The five tested intrachromosomal asymmetry indexes indicated Sarcoglottis grandiflora as the species with the most symmetrical karyotype and Christensonella pachyphylla with the most asymmetrical karyotype. In the cluster analysis, the largest number of species were grouped with the intermediary ideal karyotypes B or C. Considering our results, we recommend the combined use of at least two indexes, especially Ask% or A1 with Syi, for cytotaxonomic analysis in groups of orchids. In an evolutionary perspective, our results support Stebbins' hypothesis that asymmetric karyotypes derive from a symmetric karyotypes.

[Diagnosis of facial and craniofacial asymmetry].

PubMed

Arnaud, E; Marchac, D; Renier, D

2001-10-01

Craniofacial asymmetry is caused by various aetiologies but clinical examination remains the most important criteria since minor asymmetry is always present. The diagnosis can be confirmed by anthropometric measurements and radiological examinations but only severe asymmetries or asymmetries with an associated functional impairment should be treated. The treatment depends on the cause, and on the time of appearance. Congenital asymmetries might be treated early, during the first year of life if a craniosynostosis is present. Hemifacial microsomia are treated later if there is no breathing impairment. Since the pediatricians have recommended the dorsal position for infant sleeping, an increasing number of posterior flattening of the skull has been appearing, and could be prevented by adequate nursing. Other causes of craniofacial asymmetries are rare and should be adapted to the cause (tumors, atrophies, neurological paralysis, hypertrophies) by a specialized multidisciplinar team.

First Measurement of Transverse-Spin-Dependent Azimuthal Asymmetries in the Drell-Yan Process.

PubMed

Aghasyan, M; Akhunzyanov, R; Alexeev, G D; Alexeev, M G; Amoroso, A; Andrieux, V; Anfimov, N V; Anosov, V; Antoshkin, A; Augsten, K; Augustyniak, W; Austregesilo, A; Azevedo, C D R; Badełek, B; Balestra, F; Ball, M; Barth, J; Beck, R; Bedfer, Y; Bernhard, J; Bicker, K; Bielert, E R; Birsa, R; Bodlak, M; Bordalo, P; Bradamante, F; Bressan, A; Büchele, M; Chang, W-C; Chatterjee, C; Chiosso, M; Choi, I; Chung, S-U; Cicuttin, A; Crespo, M L; Dalla Torre, S; Dasgupta, S S; Dasgupta, S; Denisov, O Yu; Dhara, L; Donskov, S V; Doshita, N; Dreisbach, Ch; Dünnweber, W; Dziewiecki, M; Efremov, A; Eversheim, P D; Faessler, M; Ferrero, A; Finger, M; Finger, M; Fischer, H; Franco, C; du Fresne von Hohenesche, N; Friedrich, J M; Frolov, V; Fuchey, E; Gautheron, F; Gavrichtchouk, O P; Gerassimov, S; Giarra, J; Giordano, F; Gnesi, I; Gorzellik, M; Grasso, A; Grosse Perdekamp, M; Grube, B; Grussenmeyer, T; Guskov, A; Hahne, D; Hamar, G; von Harrach, D; Heinsius, F H; Heitz, R; Herrmann, F; Horikawa, N; d'Hose, N; Hsieh, C-Y; Huber, S; Ishimoto, S; Ivanov, A; Ivanshin, Yu; Iwata, T; Jary, V; Joosten, R; Jörg, P; Kabuß, E; Kerbizi, A; Ketzer, B; Khaustov, G V; Khokhlov, Yu A; Kisselev, Yu; Klein, F; Koivuniemi, J H; Kolosov, V N; Kondo, K; Königsmann, K; Konorov, I; Konstantinov, V F; Kotzinian, A M; Kouznetsov, O M; Kral, Z; Krämer, M; Kremser, P; Krinner, F; Kroumchtein, Z V; Kulinich, Y; Kunne, F; Kurek, K; Kurjata, R P; Kveton, A; Lednev, A A; Levillain, M; Levorato, S; Lian, Y-S; Lichtenstadt, J; Longo, R; Maggiora, A; Magnon, A; Makins, N; Makke, N; Mallot, G K; Marianski, B; Martin, A; Marzec, J; Matoušek, J; Matsuda, H; Matsuda, T; Meshcheryakov, G V; Meyer, M; Meyer, W; Mikhailov, Yu V; Mikhasenko, M; Mitrofanov, E; Mitrofanov, N; Miyachi, Y; Nagaytsev, A; Nerling, F; Neyret, D; Nový, J; Nowak, W-D; Nukazuka, G; Nunes, A S; Olshevsky, A G; Orlov, I; Ostrick, M; Panzieri, D; Parsamyan, B; Paul, S; Peng, J-C; Pereira, F; Pešek, M; Peshekhonov, D V; Pierre, N; Platchkov, S; Pochodzalla, J; Polyakov, V A; Pretz, J; Quaresma, M; Quintans, C; Ramos, S; Regali, C; Reicherz, G; Riedl, C; Rogacheva, N S; Roskot, M; Ryabchikov, D I; Rybnikov, A; Rychter, A; Salac, R; Samoylenko, V D; Sandacz, A; Santos, C; Sarkar, S; Savin, I A; Sawada, T; Sbrizzai, G; Schiavon, P; Schmidt, K; Schmieden, H; Schönning, K; Seder, E; Selyunin, A; Shevchenko, O Yu; Silva, L; Sinha, L; Sirtl, S; Slunecka, M; Smolik, J; Srnka, A; Steffen, D; Stolarski, M; Subrt, O; Sulc, M; Suzuki, H; Szabelski, A; Szameitat, T; Sznajder, P; Takewaka, S; Tasevsky, M; Tessaro, S; Terça, G; Tessarotto, F; Thiel, A; Tomsa, J; Tosello, F; Tskhay, V; Uhl, S; Vauth, A; Veloso, J; Virius, M; Vit, M; Vondra, J; Wallner, S; Weisrock, T; Wilfert, M; Ter Wolbeek, J; Zaremba, K; Zavada, P; Zavertyaev, M; Zemlyanichkina, E; Zhuravlev, N; Ziembicki, M

2017-09-15

The first measurement of transverse-spin-dependent azimuthal asymmetries in the pion-induced Drell-Yan (DY) process is reported. We use the CERN SPS 190  GeV/c π^{-} beam and a transversely polarized ammonia target. Three azimuthal asymmetries giving access to different transverse-momentum-dependent (TMD) parton distribution functions (PDFs) are extracted using dimuon events with invariant mass between 4.3  GeV/c^{2} and 8.5  GeV/c^{2}. Within the experimental uncertainties, the observed sign of the Sivers asymmetry is found to be consistent with the fundamental prediction of quantum chromodynamics (QCD) that the Sivers TMD PDFs extracted from DY have a sign opposite to the one extracted from semi-inclusive deep-inelastic scattering (SIDIS) data. We present two other asymmetries originating from the pion Boer-Mulders TMD PDFs convoluted with either the nucleon transversity or pretzelosity TMD PDFs. A recent COMPASS SIDIS measurement was obtained at a hard scale comparable to that of these DY results. This opens the way for possible tests of fundamental QCD universality predictions.

Unusual Voltage-Gated Sodium Currents as Targets for Pain.

PubMed

Barbosa, C; Cummins, T R

2016-01-01

Pain is a serious health problem that impacts the lives of many individuals. Hyperexcitability of peripheral sensory neurons contributes to both acute and chronic pain syndromes. Because voltage-gated sodium currents are crucial to the transmission of electrical signals in peripheral sensory neurons, the channels that underlie these currents are attractive targets for pain therapeutics. Sodium currents and channels in peripheral sensory neurons are complex. Multiple-channel isoforms contribute to the macroscopic currents in nociceptive sensory neurons. These different isoforms exhibit substantial variations in their kinetics and pharmacology. Furthermore, sodium current complexity is enhanced by an array of interacting proteins that can substantially modify the properties of voltage-gated sodium channels. Resurgent sodium currents, atypical currents that can enhance recovery from inactivation and neuronal firing, are increasingly being recognized as playing potentially important roles in sensory neuron hyperexcitability and pain sensations. Here we discuss unusual sodium channels and currents that have been identified in nociceptive sensory neurons, describe what is known about the molecular determinants of the complex sodium currents in these neurons. Finally, we provide an overview of therapeutic strategies to target voltage-gated sodium currents in nociceptive neurons. Copyright © 2016 Elsevier Inc. All rights reserved.

Study of Double Spin Asymmetries in Inclusive ep Scattering at Jefferson Lab

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Hoyoung

2014-08-01

The spin structure of the proton has been investigated in the high Bjorken x and low momentum transfer Q 2 region. We used Jefferson Lab's polarized electron beam, a polarized target, and a spectrometer to get both the parallel and perpendicular spin asymmetries Apar and Aperp. These asymmetries produced the physics asymmetries A_1 and A_2 and spin structure functions g_1 and g_2. We found Q 2 dependences of the asymmetries at resonance region and higher-twist effects. Our result increases the available data on the proton spin structure, especially at resonance region with low Q 2. Moreover, A_2 and g_2 datamore » show clear Q 2 evolution, comparing with RSS and SANE-BETA. Negative resonance in A_2 data needs to be examined by theory. It can be an indication of very negative transverse-longitudinal interference contribution at W ~ 1.3 GeV. Higher twist effect appears at the low Q 2 of 1.9 GeV 2, although it is less significant than lower Q 2 data of RSS. Twist03 matrix element d_2 was calculated using our asymmetry fits evaluation at Q 2 – 1.9 GeV 2. D-bar_2 = -0.0087±0.0014 was obtained by integrating 0.47 ≤ x ≤ 0.87.« less

Advances in target design for heavy ion fusion

NASA Astrophysics Data System (ADS)

Callahan, D. A.; Tabak, M.; Bennett, G. R.; Cuneo, M. E.; Vesey, R. A.; Nikroo, A.; Czechowicz, D.; Steinman, D.

2005-12-01

Over the past few years, the emphasis in heavy ion target design has moved from the distributed radiator target to the 'hybrid' target because the hybrid target allows a larger beam focal spot than the distributed radiator (~5 mm radius rather than ~2 mm radius). The larger spot relaxes some of the requirements on the driver, but introduces some new target physics issues. Most notable is the use of shine shields and shims in the hohlraum to achieve symmetry rather than achieving symmetry by beam placement. The shim is a thin layer of material placed on or near the capsule surface to block a small amount of excess radiation. While we have been developing this technique for the heavy ion hybrid target, the technique can also be used in any indirect drive target. We have begun testing the concept of a shim to improve symmetry using a double-ended z-pinch hohlraum on the Sandia Z-machine. Experiments using shimmed thin wall capsules have shown that we can reverse the sign of a P2 asymmetry and significantly reduce the size of a P4 asymmetry. These initial experiments demonstrate the concept of a shim as another method for controlling early time asymmetries in ICF capsules.

Assessing and conceptualizing frontal EEG asymmetry: An updated primer on recording, processing, analyzing, and interpreting frontal alpha asymmetry.

PubMed

Smith, Ezra E; Reznik, Samantha J; Stewart, Jennifer L; Allen, John J B

2017-01-01

Frontal electroencephalographic (EEG) alpha asymmetry is widely researched in studies of emotion, motivation, and psychopathology, yet it is a metric that has been quantified and analyzed using diverse procedures, and diversity in procedures muddles cross-study interpretation. The aim of this article is to provide an updated tutorial for EEG alpha asymmetry recording, processing, analysis, and interpretation, with an eye towards improving consistency of results across studies. First, a brief background in alpha asymmetry findings is provided. Then, some guidelines for recording, processing, and analyzing alpha asymmetry are presented with an emphasis on the creation of asymmetry scores, referencing choices, and artifact removal. Processing steps are explained in detail, and references to MATLAB-based toolboxes that are helpful for creating and investigating alpha asymmetry are noted. Then, conceptual challenges and interpretative issues are reviewed, including a discussion of alpha asymmetry as a mediator/moderator of emotion and psychopathology. Finally, the effects of two automated component-based artifact correction algorithms-MARA and ADJUST-on frontal alpha asymmetry are evaluated. Copyright © 2016 Elsevier B.V. All rights reserved.

Dichotic listening in patients with situs inversus: brain asymmetry and situs asymmetry.

PubMed

Tanaka, S; Kanzaki, R; Yoshibayashi, M; Kamiya, T; Sugishita, M

1999-06-01

In order to investigate the relation between situs asymmetry and functional asymmetry of the human brain, a consonant-vowel syllable dichotic listening test known as the Standard Dichotic Listening Test (SDLT) was administered to nine subjects with situs inversus (SI) that ranged in age from 6 to 46 years old (mean of 21.8 years old, S.D. = 15.6); the four males and five females all exhibited strong right-handedness. The SDLT was also used to study twenty four age-matched normal subjects that were from 6 to 48 years old (mean 21.7 years old, S.D. = 15.3); the twelve males and twelve females were all strongly right-handed and served as a control group. Eight out of the nine subjects (88.9%) with SI more often reproduced the sounds from the right ear than sounds from the left ear; this is called right ear advantage (REA). The ratio of REA in the control group was almost the same, i.e., nineteen out of the twenty-four subjects (79.1%) showed REA. Results of the present study suggest that the left-right reversal in situs inversus does not involve functional asymmetry of the brain. As such, the system that produces functional asymmetry in the human brain must independently recognize laterality from situs asymmetry.

Left‐right asymmetry in the light of TOR: An update on what we know so far

PubMed Central

Casar Tena, Teresa

2015-01-01

The internal left‐right (LR) asymmetry is a characteristic that exists throughout the animal kingdom from roundworms over flies and fish to mammals. Cilia, which are antenna‐like structures protruding into the extracellular space, are involved in establishing LR asymmetry during early development. Humans who suffer from dysfunctional cilia often develop conditions such as heterotaxy, where internal organs appear to be placed randomly. As a consequence to this failure in asymmetry development, serious complications such as congenital heart defects (CHD) occur. The mammalian (or mechanistic) target of rapamycin (mTOR) pathway has recently emerged as an important regulator regarding symmetry breaking. The mTOR pathway governs fundamental processes such as protein translation or metabolism. Its activity can be transduced by two complexes, which are called TORC1 and TORC2, respectively. So far, only TORC1 has been implicated with asymmetry development and appears to require very precise regulation. A number of recent papers provided evidence that dysregulated TORC1 results in alterations of motile cilia and asymmetry defects. In here, we give an update on what we know so far of mTORC1 in LR asymmetry development. PMID:25943139

High-current fast electron beam propagation in a dielectric target.

PubMed

Klimo, Ondrej; Tikhonchuk, V T; Debayle, A

2007-01-01

Recent experiments demonstrate an efficient transformation of high intensity laser pulse into a relativistic electron beam with a very high current density exceeding 10(12) A cm(-2). The propagation of such a beam inside the target is possible if its current is neutralized. This phenomenon is not well understood, especially in dielectric targets. In this paper, we study the propagation of high current density electron beam in a plastic target using a particle-in-cell simulation code. The code includes both ionization of the plastic and collisions of newborn electrons. The numerical results are compared with a relatively simple analytical model and a reasonable agreement is found. The temporal evolution of the beam velocity distribution, the spatial density profile, and the propagation velocity of the ionization front are analyzed and their dependencies on the beam density and energy are discussed. The beam energy losses are mainly due to the target ionization induced by the self-generated electric field and the return current. For the highest beam density, a two-stream instability is observed to develop in the plasma behind the ionization front and it contributes to the beam energy losses.

Black–white asymmetry in visual perception

PubMed Central

Lu, Zhong-Lin; Sperling, George

2012-01-01

With eleven different types of stimuli that exercise a wide gamut of spatial and temporal visual processes, negative perturbations from mean luminance are found to be typically 25% more effective visually than positive perturbations of the same magnitude (range 8–67%). In Experiment 12, the magnitude of the black–white asymmetry is shown to be a saturating function of stimulus contrast. Experiment 13 shows black–white asymmetry primarily involves a nonlinearity in the visual representation of decrements. Black–white asymmetry in early visual processing produces even-harmonic distortion frequencies in all ordinary stimuli and in illusions such as the perceived asymmetry of optically perfect sine wave gratings. In stimuli intended to stimulate exclusively second-order processing in which motion or shape are defined not by luminance differences but by differences in texture contrast, the black–white asymmetry typically generates artifactual luminance (first-order) motion and shape components. Because black–white asymmetry pervades psychophysical and neurophysiological procedures that utilize spatial or temporal variations of luminance, it frequently needs to be considered in the design and evaluation of experiments that involve visual stimuli. Simple procedures to compensate for black–white asymmetry are proposed. PMID:22984221

Targeting microbial biofilms: current and prospective therapeutic strategies

PubMed Central

Koo, Hyun; Allan, Raymond N; Howlin, Robert P; Hall-Stoodley, Luanne; Stoodley, Paul

2017-01-01

Biofilm formation is a key virulence factor for a wide range of microorganisms that cause chronic infections. The multifactorial nature of biofilm development and drug tolerance imposes great challenges for the use of conventional antimicrobials, and indicates the need for multi-targeted or combinatorial therapies. In this review, we focus on current therapeutic strategies and those that are under development that target vital structural and functional traits of microbial biofilms and drug tolerance mechanisms, including the extracellular matrix and dormant cells. We emphasize strategies that are supported by in vivo or ex vivo studies, highlight emerging biofilm-targeting technologies, and provide a rationale for multi-targeted therapies that are aimed at disrupting the complex biofilm microenvironment. PMID:28944770

Intrachromosomal karyotype asymmetry in Orchidaceae

PubMed Central

Medeiros-Neto, Enoque; Nollet, Felipe; Moraes, Ana Paula; Felix, Leonardo P.

2017-01-01

Abstract The asymmetry indexes have helped cytotaxonomists to interpret and classify plant karyotypes for species delimitation efforts. However, there is no consensus about the best method to calculate the intrachromosomal asymmetry. The present study aimed to compare different intrachromosomal asymmetry indexes in order to indicate which are more efficient for the estimation of asymmetry in different groups of orchids. Besides, we aimed to compare our results with the Orchidaceae phylogenetic proposal to test the hypothesis of Stebbins (1971). Through a literature review, karyotypes were selected and analyzed comparatively with ideal karyotypes in a cluster analysis. All karyotypes showed some level of interchromosomal asymmetry, ranging from slightly asymmetric to moderately asymmetric. The five tested intrachromosomal asymmetry indexes indicated Sarcoglottis grandiflora as the species with the most symmetrical karyotype and Christensonella pachyphylla with the most asymmetrical karyotype. In the cluster analysis, the largest number of species were grouped with the intermediary ideal karyotypes B or C. Considering our results, we recommend the combined use of at least two indexes, especially Ask% or A1 with Syi, for cytotaxonomic analysis in groups of orchids. In an evolutionary perspective, our results support Stebbins’ hypothesis that asymmetric karyotypes derive from a symmetric karyotypes. PMID:28644507

Regulatory behavior and frontal activity: Considering the role of revised-BIS in relative right frontal asymmetry.

PubMed

Gable, Philip A; Neal, Lauren B; Threadgill, A Hunter

2018-01-01

Essential to human behavior are three core personality systems: approach, avoidance, and a regulatory system governing the two motivational systems. Decades of research has linked approach motivation with greater relative left frontal-cortical asymmetry. Other research has linked avoidance motivation with greater relative right frontal-cortical asymmetry. However, past work linking withdrawal motivation with greater relative right frontal asymmetry has been mixed. The current article reviews evidence suggesting that activation of the regulatory system (revised Behavioral Inhibition System [r-BIS]) may be more strongly related to greater relative right frontal asymmetry than withdrawal motivation. Specifically, research suggests that greater activation of the r-BIS is associated with greater relative right frontal activity, and reduced r-BIS activation is associated with reduced right frontal activity (greater relative left frontal activity). We review evidence examining trait and state frontal activity using EEG, source localization, lesion studies, neuronal stimulation, and fMRI supporting the idea that r-BIS may be the core personality system related to greater relative right frontal activity. In addition, the current review seeks to disentangle avoidance motivation and r-BIS as substrates of relative right frontal asymmetry. © 2017 Society for Psychophysiological Research.

Bilateral asymmetry prediction.

PubMed

Kostoff, Ronald Neil

2003-08-01

This study predicts asymmetries in lateral organ cancer incidence from text mining of the Medline database. Lung, kidney, teste, and ovary cancers were examined. For each cancer, Medline case report articles focused solely on (1) cancer of the right organ and (2) cancer of the left organ were retrieved. The ratio of right organ to left organ articles was compared to actual patient incidence data obtained from the National Cancer Institute's (NCI) SEER database for the period 1979-1998. The agreement between the Medline record ratios and the NCI's patient incidence data ratios ranged from within 3% for lung cancer to within 1% for teste and ovary cancer. This is the first known study to generate cancer lateral incidence asymmetries from the Medline database. The technique should be applicable to other diseases and other types of system asymmetries.

Fluctuating Asymmetry and Intelligence

ERIC Educational Resources Information Center

Bates, Timothy C.

2007-01-01

The general factor of mental ability ("g") may reflect general biological fitness. If so, "g"-loaded measures such as Raven's progressive matrices should be related to morphological measures of fitness such as fluctuating asymmetry (FA: left-right asymmetry of a set of typically left-right symmetrical body traits such as finger…

Directional asymmetries in human smooth pursuit eye movements.

PubMed

Ke, Sally R; Lam, Jessica; Pai, Dinesh K; Spering, Miriam

2013-06-27

Humans make smooth pursuit eye movements to bring the image of a moving object onto the fovea. Although pursuit accuracy is critical to prevent motion blur, the eye often falls behind the target. Previous studies suggest that pursuit accuracy differs between motion directions. Here, we systematically assess asymmetries in smooth pursuit. In experiment 1, binocular eye movements were recorded while observers (n = 20) tracked a small spot of light moving along one of four cardinal or diagonal axes across a featureless background. We analyzed pursuit latency, acceleration, peak velocity, gain, and catch-up saccade latency, number, and amplitude. In experiment 2 (n = 22), we examined the effects of spatial location and constrained stimulus motion within the upper or lower visual field. Pursuit was significantly faster (higher acceleration, peak velocity, and gain) and smoother (fewer and later catch-up saccades) in response to downward versus upward motion in both the upper and the lower visual fields. Pursuit was also more accurate and smoother in response to horizontal versus vertical motion. CONCLUSIONS. Our study is the first to report a consistent up-down asymmetry in human adults, regardless of visual field. Our findings suggest that pursuit asymmetries are adaptive responses to the requirements of the visual context: preferred motion directions (horizontal and downward) are more critical to our survival than nonpreferred ones.

Diversity and convergence in the mechanisms establishing L/R asymmetry in metazoa

PubMed Central

Coutelis, Jean-Baptiste; González-Morales, Nicanor; Géminard, Charles; Noselli, Stéphane

2014-01-01

Differentiating left and right hand sides during embryogenesis represents a major event in body patterning. Left–Right (L/R) asymmetry in bilateria is essential for handed positioning, morphogenesis and ultimately the function of organs (including the brain), with defective L/R asymmetry leading to severe pathologies in human. How and when symmetry is initially broken during embryogenesis remains debated and is a major focus in the field. Work done over the past 20 years, in both vertebrate and invertebrate models, has revealed a number of distinct pathways and mechanisms important for establishing L/R asymmetry and for spreading it to tissues and organs. In this review, we summarize our current knowledge and discuss the diversity of L/R patterning from cells to organs during evolution. PMID:25150102

Predicting the Noise of High Power Fluid Targets Using Computational Fluid Dynamics

NASA Astrophysics Data System (ADS)

Moore, Michael; Covrig Dusa, Silviu

The 2.5 kW liquid hydrogen (LH2) target used in the Qweak parity violation experiment is the highest power LH2 target in the world and the first to be designed with Computational Fluid Dynamics (CFD) at Jefferson Lab. The Qweak experiment determined the weak charge of the proton by measuring the parity-violating elastic scattering asymmetry of longitudinally polarized electrons from unpolarized liquid hydrogen at small momentum transfer (Q2 = 0 . 025 GeV2). This target satisfied the design goals of < 1 % luminosity reduction and < 5 % contribution to the total asymmetry width (the Qweak target achieved 2 % or 55ppm). State of the art time dependent CFD simulations are being developed to improve the predictions of target noise on the time scale of the electron beam helicity period. These predictions will be bench-marked with the Qweak target data. This work is an essential component in future designs of very high power low noise targets like MOLLER (5 kW, target noise asymmetry contribution < 25 ppm) and MESA (4.5 kW).

Enhancing Spin Filters by Use of Bulk Inversion Asymmetry

NASA Technical Reports Server (NTRS)

Ting, David; Cartoixa,Xavier

2007-01-01

Theoretical calculations have shown that the degrees of spin polarization in proposed nonmagnetic semiconductor resonant tunneling spin filters could be increased through exploitation of bulk inversion asymmetry (BIA). These enhancements would be effected through suitable orientation of spin collectors (or spin-polarization- inducing lateral electric fields), as described below. Spin filters -- more precisely, sources of spin-polarized electron currents -- have been sought for research on, and development of, the emerging technological discipline of spintronics (spin-transport electronics). The proposed spin filters were to be based on the Rashba effect, which is an energy splitting of what would otherwise be degenerate quantum states, caused by a spinorbit interaction in conjunction with a structural-inversion asymmetry (SIA) in the presence of interfacial electric fields in a semiconductor heterostructure. The magnitude of the energy split is proportional to the electron wave number. In a spin filter, the spin-polarized currents produced by the Rashba effect would be extracted by quantum-mechanical resonant tunneling.

Generation of the relic neutrino asymmetry in a hot plasma of the early universe

NASA Astrophysics Data System (ADS)

Semikoz, Victor B.; Dvornikov, Maxim

The neutrino asymmetry in the early universe plasma, nν ‑ nν¯, is calculated both before and after the electroweak phase transition (EWPT). In the Standard Model, before EWPT, the leptogenesis is well known to be driven by the abelian anomaly in a massless hypercharge field. The generation of the neutrino asymmetry in the Higgs phase after EWPT, in its turn, has not been considered previously because of the absence of any quantum anomaly in an external electromagnetic field for such electroneutral particles as neutrino, unlike the Adler-Bell-Jackiw anomaly for charged left and right polarized massless electrons in the same electromagnetic field. Using the neutrino Boltzmann equation, modified by the Berry curvature term in the momentum space, we establish the violation of the macroscopic neutrino current in plasma after EWPT and exactly reproduce the nonconservation of the lepton current in the symmetric phase before EWPT arising in quantum field theory due to the nonzero lepton hypercharge and corresponding triangle anomaly in an external hypercharge field. In the last case, the nonconservation of the lepton current is derived through the kinetic approach without a computation of corresponding Feynman diagrams. Then, the new kinetic equation is applied for the calculation of the neutrino asymmetry accounting for the Berry curvature and the electroweak interaction with background fermions in the Higgs phase. Such an interaction generates a neutrino asymmetry through the electroweak coupling of neutrino currents with electromagnetic fields in plasma, which is ˜ GF2. It turns out that this effect is especially efficient for maximally helical magnetic fields.

Asymmetries of solar oscillation line profiles

NASA Technical Reports Server (NTRS)

Duvall, T. L., Jr.; Jefferies, S. M.; Harvey, J. W.; Osaki, Y.; Pomerantz, M. A.

1993-01-01

Asymmetries of the power spectral line profiles of solar global p-modes are detected in full-disk intensity observations of the Ca II K Fraunhofer line. The asymmetry is a strong function of temporal frequency being strongest at the lowest frequencies observed and vanishing near the peak of the power distribution. The variation with spherical harmonic degree is small. The asymmetry is interpreted in terms of a model in which the solar oscillation cavity is compared to a Fabry-Perot interferometer with the source slightly outside the cavity. A phase difference between an outward direct wave and a corresponding inward wave that passes through the cavity gives rise to the asymmetry. The asymmetry is different in velocity and intensity observations. Neglecting the asymmetry when modeling the power spectrum can lead to systematic errors in the measurement of mode frequencies of as much as 10 exp -4 of the mode frequency. The present observations and interpretation locate the source of the oscillations to be approximately 60 km beneath the photosphere, the shallowest position suggested to date.

Intrahemispheric white matter asymmetries: the missing link between brain structure and functional lateralization?

PubMed

Ocklenburg, Sebastian; Friedrich, Patrick; Güntürkün, Onur; Genç, Erhan

2016-07-01

Hemispheric asymmetries are a central principle of nervous system architecture and shape the functional organization of most cognitive systems. Structural gray matter asymmetries and callosal interactions have been identified as contributing neural factors but always fell short to constitute a full explanans. Meanwhile, recent advances in in vivo white matter tractography have unrevealed the asymmetrical organization of many intrahemispheric white matter pathways, which might serve as the missing link to explain the substrate of functional lateralization. By taking into account callosal interactions, gray matter asymmetries and asymmetrical interhemispheric pathways, we opt for a new triadic model that has the potential to explain many observations which cannot be elucidated within the current frameworks of lateralized cognition.

Bilateral Asymmetry in the Human Pelvis.

PubMed

Kurki, Helen K

2017-04-01

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

Synaptic Plasticity and Memory: New Insights from Hippocampal Left-Right Asymmetries.

PubMed

El-Gaby, Mohamady; Shipton, Olivia A; Paulsen, Ole

2015-10-01

All synapses are not the same. They differ in their morphology, molecular constituents, and malleability. A striking left-right asymmetry in the distribution of different types of synapse was recently uncovered at the CA3-CA1 projection in the mouse hippocampus, whereby afferents from the CA3 in the left hemisphere innervate small, highly plastic synapses on the apical dendrites of CA1 pyramidal neurons, whereas those originating from the right CA3 target larger, more stable synapses. Activity-dependent modification of these synapses is thought to participate in circuit formation and remodeling during development, and further plastic changes may support memory encoding in adulthood. Therefore, exploiting the CA3-CA1 asymmetry provides a promising opportunity to investigate the roles that different types of synapse play in these fundamental properties of the CNS. Here we describe the discovery of these segregated synaptic populations in the mouse hippocampus, and discuss what we have already learnt about synaptic plasticity from this asymmetric arrangement. We then propose models for how the asymmetry could be generated during development, and how the adult hippocampus might use these distinct populations of synapses differentially during learning and memory. Finally, we outline the potential implications of this left-right asymmetry for human hippocampal function, as well as dysfunction in memory disorders such as Alzheimer's disease. © The Author(s) 2014.

Perceptual Grouping, Not Emotion, Accounts for Search Asymmetries with Schematic Faces

ERIC Educational Resources Information Center

Becker, Stefanie I.; Horstmann, Gernot; Remington, Roger W.

2011-01-01

Several different explanations have been proposed to account for the search asymmetry (SA) for angry schematic faces (i.e., the fact that an angry face target among friendly faces can be found faster than vice versa). The present study critically tested the perceptual grouping account, (a) that the SA is not due to emotional factors, but to…

Cp Asymmetries in B0DECAYS Beyond the Standard Model

NASA Astrophysics Data System (ADS)

Dib, Claudio O.; London, David; Nir, Yosef

Of the many ingredients of the Standard Model that are relevant to the analysis of CP asymmetries in B0 decays, some are likely to hold even beyond the Standard Model while others are sensitive to new physics. Consequently, certain predictions are maintained while others may show dramatic deviations from the Standard Model. Many classes of models may show clear signatures when the asymmetries are measured: four quark generations, Z-mediated flavor-changing neutral currents, supersymmetry and “real superweak” models. On the other hand, models of left-right symmetry and multi-Higgs sectors with natural flavor conservation are unlikely to modify the Standard Model predictions.

Measurement of the Parity-Violating Asymmetries in Electron-Deuteron Scattering in the Nucleon Resonance Region

DOE PAGES

Wang, Diancheng; Pan, Kai; Subedi, Ramesh R.; ...

2013-08-22

We report on parity-violating asymmetries in the nucleon resonance region measured using 5 - 6 GeV longitudinally polarized electrons scattering off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the Δ(1232), and provide a verification of quark-hadron duality in the nucleon electroweak γ Z interference structure functions at the (10-15)% level. The results are of particular interest to models relevant for calculating the γ Z box-diagram corrections to elastic parity-violating electron scattering measurements.

The evolution and genetics of cerebral asymmetry

PubMed Central

Corballis, Michael C.

2008-01-01

Handedness and cerebral asymmetry are commonly assumed to be uniquely human, and even defining characteristics of our species. This is increasingly refuted by the evidence of behavioural asymmetries in non-human species. Although complex manual skill and language are indeed unique to our species and are represented asymmetrically in the brain, some non-human asymmetries appear to be precursors, and others are shared between humans and non-humans. In all behavioural and cerebral asymmetries so far investigated, a minority of individuals reverse or negate the dominant asymmetry, suggesting that such asymmetries are best understood in the context of the overriding bilateral symmetry of the brain and body, and a trade-off between the relative advantages and disadvantages of symmetry and asymmetry. Genetic models of handedness, for example, typically postulate a gene with two alleles, one disposing towards right-handedness and the other imposing no directional influence. There is as yet no convincing evidence as to the location of this putative gene, suggesting that several genes may be involved, or that the gene may be monomorphic with variations due to environmental or epigenetic influences. Nevertheless, it is suggested that, in behavioural, neurological and evolutionary terms, it may be more profitable to examine the degree rather than the direction of asymmetry. PMID:19064358

The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex

PubMed Central

Jeong, Su Keun; Xu, Yaoda

2016-01-01

The human parietal cortex exhibits a preference to contralaterally presented visual stimuli (i.e., laterality) as well as an asymmetry between the two hemispheres with the left parietal cortex showing greater laterality than the right. Using visual short-term memory and perceptual tasks and varying target location predictability, this study examined whether hemispheric laterality and asymmetry are fixed characteristics of the human parietal cortex or whether they are dynamic and modulated by the deployment of top-down attention to the target present hemifield. Two parietal regions were examined here that have previously been shown to be involved in visual object individuation and identification and are located in the inferior and superior intraparietal sulcus (IPS), respectively. Across three experiments, significant laterality was found in both parietal regions regardless of attentional modulation with laterality being greater in the inferior than superior IPS, consistent with their roles in object individuation and identification, respectively. Although the deployment of top-down attention had no effect on the superior IPS, it significantly increased laterality in the inferior IPS. The deployment of top-down spatial attention can thus amplify the strength of laterality in the inferior IPS. Hemispheric asymmetry, on the other hand, was absent in both brain regions and only emerged in the inferior but not the superior IPS with the deployment of top-down attention. Interestingly, the strength of hemispheric asymmetry significantly correlated with the strength of laterality in the inferior IPS. Hemispheric asymmetry thus seems to only emerge when there is a sufficient amount of laterality present in a brain region. PMID:27494544

The impact of top-down spatial attention on laterality and hemispheric asymmetry in the human parietal cortex.

PubMed

Jeong, Su Keun; Xu, Yaoda

2016-08-01

The human parietal cortex exhibits a preference to contralaterally presented visual stimuli (i.e., laterality) as well as an asymmetry between the two hemispheres with the left parietal cortex showing greater laterality than the right. Using visual short-term memory and perceptual tasks and varying target location predictability, this study examined whether hemispheric laterality and asymmetry are fixed characteristics of the human parietal cortex or whether they are dynamic and modulated by the deployment of top-down attention to the target present hemifield. Two parietal regions were examined here that have previously been shown to be involved in visual object individuation and identification and are located in the inferior and superior intraparietal sulcus (IPS), respectively. Across three experiments, significant laterality was found in both parietal regions regardless of attentional modulation with laterality being greater in the inferior than superior IPS, consistent with their roles in object individuation and identification, respectively. Although the deployment of top-down attention had no effect on the superior IPS, it significantly increased laterality in the inferior IPS. The deployment of top-down spatial attention can thus amplify the strength of laterality in the inferior IPS. Hemispheric asymmetry, on the other hand, was absent in both brain regions and only emerged in the inferior but not the superior IPS with the deployment of top-down attention. Interestingly, the strength of hemispheric asymmetry significantly correlated with the strength of laterality in the inferior IPS. Hemispheric asymmetry thus seems to only emerge when there is a sufficient amount of laterality present in a brain region.

Frontal alpha asymmetry as a pathway to behavioural withdrawal in depression: Research findings and issues.

PubMed

Jesulola, Emmanuel; Sharpley, Christopher F; Bitsika, Vicki; Agnew, Linda L; Wilson, Peter

2015-10-01

Depression has been described as a process of behavioural withdrawal from overwhelming aversive stressors, and which manifests itself in the diagnostic symptomatology for Major Depressive Disorder (MDD). The underlying neurobiological pathways to that behavioural withdrawal are suggested to include greater activation in the right vs the left frontal lobes, described as frontal EEG asymmetry. However, despite a previous meta-analysis that provided overall support for this EEG asymmetry hypothesis, inconsistencies and several methodological confounds exist. The current review examines the literature on this issue, identifies inconsistencies in findings and discusses several key research issues that require addressing for this field to move towards a defensible theoretical model of depression and EEG asymmetry. In particular, the position of EEG asymmetry in the brain, measurement of severity and symptoms profiles of depression, and the effects of gender are considered as potential avenues to more accurately define the specific nature of the depression-EEG asymmetry association. Copyright © 2015 Elsevier B.V. All rights reserved.

Compensation procedures for facial asymmetries.

PubMed

Kozol, F

1995-01-01

Why would a patient complain of "fuzzy and uncomfortable" vision with a variety of glasses? Perhaps because the practitioner has failed to take facial asymmetry into account. Methods of measuring facial asymmetry and optically correcting for it are discussed.

Measurement of the Parity Violating Asymmetry in Elastic Electron Scattering off 208Pb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wexler, Jonathan

2014-09-01

The Lead Radius Experiment (PREX) was carried out in order to provide a model-independent measurement of the RMS radius √ of the neutron distribution in the 208Pb nucleus. The parity-violating scattering asymmetry for longitudinally polarized 1.06 GeV electrons from an unpolarized 208Pb target was measured at Q2 = 0.00880 GeV2. This measurement was performed by the PREX collaboration in Hall A at Jefferson Laboratory in Newport News, VA, between March and June, 2010. The electron detectors used in this measurement were designed and fabricated by University of Massachusetts-Amherst and Smith College. The resulting parity-violating asymmetry was measured as APV = 656±60(stat.)±14(sys.) ppb. This asymmetry extrapolates to a difference in radii between the nuclear neutron and proton distributions of √<$$2\\atop{n}$$>-√<$$2\\atop{p}$$>=0.33$$+0.16\\atop{-0.18}$$ fm.« less

Analytical formulation of lunar cratering asymmetries

NASA Astrophysics Data System (ADS)

Wang, Nan; Zhou, Ji-Lin

2016-10-01

Context. The cratering asymmetry of a bombarded satellite is related to both its orbit and impactors. The inner solar system impactor populations, that is, the main-belt asteroids (MBAs) and the near-Earth objects (NEOs), have dominated during the late heavy bombardment (LHB) and ever since, respectively. Aims: We formulate the lunar cratering distribution and verify the cratering asymmetries generated by the MBAs as well as the NEOs. Methods: Based on a planar model that excludes the terrestrial and lunar gravitations on the impactors and assuming the impactor encounter speed with Earth venc is higher than the lunar orbital speed vM, we rigorously integrated the lunar cratering distribution, and derived its approximation to the first order of vM/venc. Numerical simulations of lunar bombardment by the MBAs during the LHB were performed with an Earth-Moon distance aM = 20-60 Earth radii in five cases. Results: The analytical model directly proves the existence of a leading/trailing asymmetry and the absence of near/far asymmetry. The approximate form of the leading/trailing asymmetry is (1 + A1cosβ), which decreases as the apex distance β increases. The numerical simulations show evidence of a pole/equator asymmetry as well as the leading/trailing asymmetry, and the former is empirically described as (1 + A2cos2ϕ), which decreases as the latitude modulus | ϕ | increases. The amplitudes A1,2 are reliable measurements of asymmetries. Our analysis explicitly indicates the quantitative relations between cratering distribution and bombardment conditions (impactor properties and the lunar orbital status) like A1 ∝ vM/venc, resulting in a method for reproducing the bombardment conditions through measuring the asymmetry. Mutual confirmation between analytical model and numerical simulations is found in terms of the cratering distribution and its variation with aM. Estimates of A1 for crater density distributions generated by the MBAs and the NEOs are 0.101-0.159 and 0

Measurement and genetics of human subcortical and hippocampal asymmetries in large datasets.

PubMed

Guadalupe, Tulio; Zwiers, Marcel P; Teumer, Alexander; Wittfeld, Katharina; Vasquez, Alejandro Arias; Hoogman, Martine; Hagoort, Peter; Fernandez, Guillen; Buitelaar, Jan; Hegenscheid, Katrin; Völzke, Henry; Franke, Barbara; Fisher, Simon E; Grabe, Hans J; Francks, Clyde

2014-07-01

Functional and anatomical asymmetries are prevalent features of the human brain, linked to gender, handedness, and cognition. However, little is known about the neurodevelopmental processes involved. In zebrafish, asymmetries arise in the diencephalon before extending within the central nervous system. We aimed to identify genes involved in the development of subtle, left-right volumetric asymmetries of human subcortical structures using large datasets. We first tested the feasibility of measuring left-right volume differences in such large-scale samples, as assessed by two automated methods of subcortical segmentation (FSL|FIRST and FreeSurfer), using data from 235 subjects who had undergone MRI twice. We tested the agreement between the first and second scan, and the agreement between the segmentation methods, for measures of bilateral volumes of six subcortical structures and the hippocampus, and their volumetric asymmetries. We also tested whether there were biases introduced by left-right differences in the regional atlases used by the methods, by analyzing left-right flipped images. While many bilateral volumes were measured well (scan-rescan r = 0.6-0.8), most asymmetries, with the exception of the caudate nucleus, showed lower repeatabilites. We meta-analyzed genome-wide association scan results for caudate nucleus asymmetry in a combined sample of 3,028 adult subjects but did not detect associations at genome-wide significance (P < 5 × 10(-8) ). There was no enrichment of genetic association in genes involved in left-right patterning of the viscera. Our results provide important information for researchers who are currently aiming to carry out large-scale genome-wide studies of subcortical and hippocampal volumes, and their asymmetries. Copyright © 2013 Wiley Periodicals, Inc.

Left-right asymmetry in the level of active Nodal protein produced in the node is translated into left-right asymmetry in the lateral plate of mouse embryos.

PubMed

Kawasumi, Aiko; Nakamura, Tetsuya; Iwai, Naomi; Yashiro, Kenta; Saijoh, Yukio; Belo, Jose Antonio; Shiratori, Hidetaka; Hamada, Hiroshi

2011-05-15

Left-right (L-R) asymmetry in the mouse embryo is generated in the node and is dependent on cilia-driven fluid flow, but how the initial asymmetry is transmitted from the node to the lateral plate has remained unknown. We have now identified a transcriptional enhancer (ANE) in the human LEFTY1 gene that exhibits marked L>R asymmetric activity in perinodal cells of the mouse embryo. Dissection of ANE revealed that it is activated in the perinodal cells on the left side by Nodal signaling, suggesting that Nodal activity in the node is asymmetric at a time when Nodal expression is symmetric. Phosphorylated Smad2/3 (pSmad2) indeed manifested an L-R asymmetric distribution at the node, being detected in perinodal cells preferentially on the left side. This asymmetry in pSmad2 distribution was found to be generated not by unidirectional transport of Nodal but rather as a result of Lasymmetry in pSmad2 distribution among the perinodal cells closely matched that in lateral plate mesoderm (LPM). However, autocrine-paracrine Nodal signaling in perinodal cells is dispensable for L-R patterning of LPM, given that its inhibition by expression of dominant negative forms of Smad3 or ALK4 was still associated with normal (left-sided) Nodal expression in LPM. Our results suggest that LPM is the direct target of Nodal secreted by the perinodal cells, and that an L>R distribution of active Nodal in the node is translated into the asymmetry in LPM. Copyright © 2011 Elsevier Inc. All rights reserved.

Current siRNA Targets in Atherosclerosis and Aortic Aneurysm

PubMed Central

Pradhan-Nabzdyk, Leena; Huang, Chenyu; Logerfo, Frank W.; Nabzdyk, Christoph S.

2014-01-01

Atherosclerosis (ATH) and aortic aneurysms (AA) remain challenging chronic diseases that confer high morbidity and mortality despite advances in medical, interventional, and surgical care. RNA interference represents a promising technology that may be utilized to silence genes contributing to ATH and AA. Despite positive results in preclinical and some clinical feasibility studies, challenges such as target/sequence validation, tissue specificity, transfection efficiency, and mitigation of unwanted off-target effects remain to be addressed. In this review the most current targets and some novel approaches in siRNA delivery are being discussed. Due to the plethora of investigated targets, only studies published between 2010 and 2014 were included. PMID:24882715

Deconstructing the “Resting” State: Exploring the Temporal Dynamics of Frontal Alpha Asymmetry as an Endophenotype for Depression

PubMed Central

Allen, John J. B.; Cohen, Michael X

2010-01-01

Asymmetry in frontal electrocortical alpha-band (8–13 Hz) activity recorded during resting situations (i.e., in absence of a specific task) has been investigated in relation to emotion and depression for over 30 years. This asymmetry reflects an aspect of endogenous cortical dynamics that is stable over repeated measurements and that may serve as an endophenotype for mood or other psychiatric disorders. In nearly all of this research, EEG activity is averaged across several minutes, obscuring transient dynamics that unfold on the scale of milliseconds to seconds. Such dynamic states may ultimately have greater value in linking brain activity to surface EEG asymmetry, thus improving its status as an endophenotype for depression. Here we introduce novel metrics for characterizing frontal alpha asymmetry that provide a more in-depth neurodynamical understanding of recurrent endogenous cortical processes during the resting-state. The metrics are based on transient “bursts” of asymmetry that occur frequently during the resting-state. In a sample of 306 young adults, 143 with a lifetime diagnosis of major depressive disorder (62 currently symptomatic), three questions were addressed: (1) How do novel peri-burst metrics of dynamic asymmetry compare to conventional fast-Fourier transform-based metrics? (2) Do peri-burst metrics adequately differentiate depressed from non-depressed participants? and, (3) what EEG dynamics surround the asymmetry bursts? Peri-burst metrics correlated with traditional measures of asymmetry, and were sensitive to both current and past episodes of major depression. Moreover, asymmetry bursts were characterized by a transient lateralized alpha suppression that is highly consistent in phase across bursts, and a concurrent contralateral transient alpha enhancement that is less tightly phase-locked across bursts. This approach opens new possibilities for investigating rapid cortical dynamics during resting-state EEG. PMID:21228910

Stochastic left-right neuronal asymmetry in Caenorhabditis elegans.

PubMed

Alqadah, Amel; Hsieh, Yi-Wen; Xiong, Rui; Chuang, Chiou-Fen

2016-12-19

Left-right asymmetry in the nervous system is observed across species. Defects in left-right cerebral asymmetry are linked to several neurological diseases, but the molecular mechanisms underlying brain asymmetry in vertebrates are still not very well understood. The Caenorhabditis elegans left and right amphid wing 'C' (AWC) olfactory neurons communicate through intercellular calcium signalling in a transient embryonic gap junction neural network to specify two asymmetric subtypes, AWC OFF (default) and AWC ON (induced), in a stochastic manner. Here, we highlight the molecular mechanisms that establish and maintain stochastic AWC asymmetry. As the components of the AWC asymmetry pathway are highly conserved, insights from the model organism C. elegans may provide a window onto how brain asymmetry develops in humans.This article is part of the themed issue 'Provocative questions in left-right asymmetry'. © 2016 The Author(s).

Left-right asymmetry in the light of TOR: An update on what we know so far.

PubMed

Casar Tena, Teresa; Burkhalter, Martin D; Philipp, Melanie

2015-09-01

The internal left-right (LR) asymmetry is a characteristic that exists throughout the animal kingdom from roundworms over flies and fish to mammals. Cilia, which are antenna-like structures protruding into the extracellular space, are involved in establishing LR asymmetry during early development. Humans who suffer from dysfunctional cilia often develop conditions such as heterotaxy, where internal organs appear to be placed randomly. As a consequence to this failure in asymmetry development, serious complications such as congenital heart defects (CHD) occur. The mammalian (or mechanistic) target of rapamycin (mTOR) pathway has recently emerged as an important regulator regarding symmetry breaking. The mTOR pathway governs fundamental processes such as protein translation or metabolism. Its activity can be transduced by two complexes, which are called TORC1 and TORC2, respectively. So far, only TORC1 has been implicated with asymmetry development and appears to require very precise regulation. A number of recent papers provided evidence that dysregulated TORC1 results in alterations of motile cilia and asymmetry defects. In here, we give an update on what we know so far of mTORC1 in LR asymmetry development. © 2015 The Authors. Biology of the Cell published by John Wiley & Sons Ltd on behalf of Société Française des Microscopies and Société de Biologie Cellulaire de France.

A voxel-based asymmetry study of the relationship between hemispheric asymmetry and language dominance in Wada tested patients.

PubMed

Keller, Simon S; Roberts, Neil; Baker, Gus; Sluming, Vanessa; Cezayirli, Enis; Mayes, Andrew; Eldridge, Paul; Marson, Anthony G; Wieshmann, Udo C

2018-03-23

Determining the anatomical basis of hemispheric language dominance (HLD) remains an important scientific endeavor. The Wada test remains the gold standard test for HLD and provides a unique opportunity to determine the relationship between HLD and hemispheric structural asymmetries on MRI. In this study, we applied a whole-brain voxel-based asymmetry (VBA) approach to determine the relationship between interhemispheric structural asymmetries and HLD in a large consecutive sample of Wada tested patients. Of 135 patients, 114 (84.4%) had left HLD, 10 (7.4%) right HLD, and 11 (8.2%) bilateral language representation. Fifty-four controls were also studied. Right-handed controls and right-handed patients with left HLD had comparable structural brain asymmetries in cortical, subcortical, and cerebellar regions that have previously been documented in healthy people. However, these patients and controls differed in structural asymmetry of the mesial temporal lobe and a circumscribed region in the superior temporal gyrus, suggesting that only asymmetries of these regions were due to brain alterations caused by epilepsy. Additional comparisons between patients with left and right HLD, matched for type and location of epilepsy, revealed that structural asymmetries of insula, pars triangularis, inferior temporal gyrus, orbitofrontal cortex, ventral temporo-occipital cortex, mesial somatosensory cortex, and mesial cerebellum were significantly associated with the side of HLD. Patients with right HLD and bilateral language representation were significantly less right-handed. These results suggest that structural asymmetries of an insular-fronto-temporal network may be related to HLD. © 2018 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.

Mapping hemispheric symmetries, relative asymmetries, and absolute asymmetries underlying the auditory laterality effect.

PubMed

Westerhausen, René; Kompus, Kristiina; Hugdahl, Kenneth

2014-01-01

Functional hemispheric differences for speech and language processing have been traditionally studied by using verbal dichotic-listening paradigms. The commonly observed right-ear preference for the report of dichotically presented syllables is taken to reflect the left hemispheric dominance for speech processing. However, the results of recent functional imaging studies also show that both hemispheres - not only the left - are engaged by dichotic listening, suggesting a more complex relationship between behavioral laterality and functional hemispheric activation asymmetries. In order to more closely examine the hemispheric differences underlying dichotic-listening performance, we report an analysis of functional magnetic resonance imaging (fMRI) data of 104 right-handed subjects, for the first time combining an interhemispheric difference and conjunction analysis. This approach allowed for a distinction of homotopic brain regions which showed symmetrical (i.e., brain region significantly activated in both hemispheres and no activation difference between the hemispheres), relative asymmetrical (i.e., activated in both hemispheres but significantly stronger in one than the other hemisphere), and absolute asymmetrical activation patterns (i.e., activated only in one hemisphere and this activation is significantly stronger than in the other hemisphere). Symmetrical activation was found in large clusters encompassing temporal, parietal, inferior frontal, and medial superior frontal regions. Relative and absolute left-ward asymmetries were found in the posterior superior temporal gyrus, located adjacent to symmetrically activated areas, and creating a lateral-medial gradient from symmetrical towards absolute asymmetrical activation within the peri-Sylvian region. Absolute leftward asymmetry was also found in the post-central and medial superior frontal gyri, while rightward asymmetries were found in middle temporal and middle frontal gyri. We conclude that dichotic

FACIAL ASYMMETRY IS NEGATIVELY RELATED TO CONDITION IN FEMALE MACAQUE MONKEYS

PubMed Central

Little, Anthony C.; Paukner, Annika; Woodward, Ruth A.; Suomi, Stephen J.

2013-01-01

The face is an important visual trait in social communication across many species. In evolutionary terms there are large and obvious selective advantages in detecting healthy partners, both in terms of avoiding individuals with poor health to minimise contagion and in mating with individuals with high health to help ensure healthy offspring. Many models of sexual selection suggest that an individual’s phenotype provides cues to their quality. Fluctuating asymmetry is a trait that is proposed to be an honest indicator of quality and previous studies have demonstrated that rhesus monkeys gaze longer at symmetric faces, suggesting preferences for such faces. The current study examined the relationship between measured facial symmetry and measures of health in a captive population of female rhesus macaque monkeys. We measured asymmetry from landmarks marked on front-on facial photographs and computed measures of health based on veterinary health and condition ratings, number of minor and major wounds sustained, and gain in weight over the first four years of life. Analysis revealed that facial asymmetry was negatively related to condition related health measures, with symmetric individuals being healthier than more asymmetric individuals. Facial asymmetry appears to be an honest indicator of health in rhesus macaques and asymmetry may then be used by conspecifics in mate-choice situations. More broadly, our data support the notion that faces are valuable sources of information in non-human primates and that sexual selection based on facial information is potentially important across the primate lineage. PMID:23667290

Movement asymmetry in working polo horses.

PubMed

Pfau, T; Parkes, R S; Burden, E R; Bell, N; Fairhurst, H; Witte, T H

2016-07-01

The high, repetitive demands imposed on polo horses in training and competition may predispose them to musculoskeletal injuries and lameness. To quantify movement symmetry and lameness in a population of polo horses, and to investigate the existence of a relationship with age. Convenience sampled cross-sectional study. Sixty polo horses were equipped with inertial measurement units (IMUs) attached to the poll, and between the tubera sacrale. Six movement symmetry measures were calculated for vertical head and pelvic displacement during in-hand trot and compared with values for perfect symmetry, compared between left and right limb lame horses, and compared with published thresholds for lameness. Regression lines were calculated as a function of age of horse. Based on 2 different sets of published asymmetry thresholds 52-53% of the horses were quantified with head movement asymmetry and 27-50% with pelvic movement asymmetry resulting in 60-67% of horses being classified with movement asymmetry outside published guideline values for either the forelimbs, hindlimbs or both. Neither forelimb nor hindlimb asymmetries were preferentially left or right sided, with directional asymmetry values across all horses not different from perfect symmetry and absolute values not different between left and right lame horses (P values >0.6 for all forelimb symmetry measures and >0.2 for all hindlimb symmetry measures). None of the symmetry parameters increased or decreased significantly with age. A large proportion of polo horses show gait asymmetries consistent with previously defined thresholds for lameness. These do not appear to be lateralised or associated with age. © 2015 EVJ Ltd.

[Orthodontic treatment of Class III patients with mandibular asymmetry].

PubMed

Duan, Yin-Zhong; Huo, Na; Chen, Lei; Chen, Xue-Peng; Lin, Yang

2008-12-01

To investigate the treatment outcome of Class III patients with dental, functional and mild skeletal mandibular asymmetry. Thirty-five patients (14 males and 21 females) with dental, functional and mild skeletal mandibular asymmetry were selected. The age range of the patients was 7 - 22 years with a mean age of 16.5 years. Dental mandibular asymmetry was treated with expansion of maxillary arch to help the mandible returning to normal position. Functional mandibular asymmetry was treated with activator or asymmetrical protraction and Class III elastics. Mild skeletal mandibular asymmetry was treated with camouflage treatment. Good occlusal relationships were achieved and facial esthetics was greatly improved after orthodontic treatment in patients with dental and functional mandibular asymmetry. However, patients with skeletal mandibular asymmetry should be treated with both extraction and genioplasty. Orthodontic treatment was suitable for patients with dental and functional mandibular asymmetry, while combined orthodontics and surgery could get good results in patients with skeletal mandibular asymmetry.

Current target acquisition methodology in force on force simulations

NASA Astrophysics Data System (ADS)

Hixson, Jonathan G.; Miller, Brian; Mazz, John P.

2017-05-01

The U.S. Army RDECOM CERDEC NVESD MSD's target acquisition models have been used for many years by the military community in force on force simulations for training, testing, and analysis. There have been significant improvements to these models over the past few years. The significant improvements are the transition of ACQUIRE TTP-TAS (ACQUIRE Targeting Task Performance Target Angular Size) methodology for all imaging sensors and the development of new discrimination criteria for urban environments and humans. This paper is intended to provide an overview of the current target acquisition modeling approach and provide data for the new discrimination tasks. This paper will discuss advances and changes to the models and methodologies used to: (1) design and compare sensors' performance, (2) predict expected target acquisition performance in the field, (3) predict target acquisition performance for combat simulations, and (4) how to conduct model data validation for combat simulations.

Higher limb asymmetry in deceased human fetuses and infants with aneuploidy

PubMed Central

Bots, Jessica; ten Broek, Clara M. A.; Belien, Jeroen A. M.; Bugiani, Marianna; Galis, Frietson; Van Dongen, Stefan

2014-01-01

Aneuploidies cause gene-dosage imbalances that presumably result in a generalized decreased developmental homeostasis, which is expected to be detectable through an increase in fluctuating asymmetry (FA) of bilateral symmetric traits. However, support for the link between aneuploidy and FA is currently limited and no comparisons among different aneuploidies have been made. Here, we study FA in deceased human fetuses and infants from a 20-year hospital collection. Mean FA of limb bones was compared among groups of aneuploidies with different prenatal and postnatal survival chances and two reference groups (normal karyogram or no congenital anomalies). Limb asymmetry was 1.5 times higher for aneuploid cases with generally very short life expectancies (trisomy 13, trisomy 18, monosomy X, triploidy) than for trisomy 21 patients and both reference groups with higher life expectancies. Thus, FA levels are highest in groups for which developmental disturbances have been highest. Our results show a significant relationship between fluctuating asymmetry, human genetic disorders and severity of the associated abnormalities. PMID:24424506

Survey of A asymmetries in semi-exclusive electron scattering on 4He and 12C

NASA Astrophysics Data System (ADS)

Protopopescu, D.; Hersman, F. W.; Holtrop, M.; Adams, G.; Ambrozewicz, P.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Asryan, G.; Audit, G.; Auger, T.; Avakian, H.; Bagdasaryan, H.; Ball, J. P.; Barrow, S.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Bertozzi, W.; Bianchi, N.; Biselli, A. S.; Boiarinov, S.; Bonner, B. E.; Bouchigny, S.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Carman, D. S.; Carnahan, B.; Cetina, C.; Chen, S.; Cole, P. L.; Coleman, A.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J. P.; Debruyne, D.; De Sanctis, E.; DeVita, R.; Degtyarenko, P. V.; Dennis, L.; Dharmawardane, K. V.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Eugenio, P.; Fatemi, R.; Feuerbach, R. J.; Forest, T. A.; Funsten, H.; Gavalian, G.; Gilad, S.; Gilfoyle, G. P.; Giovanetti, K. L.; Girard, P.; Gordon, C. I. O.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hicks, K.; Hleiqawi, I.; Hu, J.; Hyde-Wright, C. E.; Ingram, W.; Ireland, D.; Ito, M. M.; Jenkins, D.; Joo, K.; Juengst, H. G.; Kelley, J. H.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kuhn, S. E.; Kuhn, J.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Lee, T.; Li, Ji; Livingston, K.; Lukashin, K.; Manak, J. J.; Marchand, C.; McAleer, S.; McLauchlan, S. T.; McNabb, J. W. C.; Mecking, B. A.; Melone, J. J.; Mestayer, M. D.; Meyer, C. A.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Morand, L.; Morrow, S. A.; Muccifora, V.; Mueller, J.; Mutchler, G. S.; Napolitano, J.; Nasseripour, R.; Nelson, S. O.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A.; Park, K.; Pasyuk, E.; Peterson, G.; Philips, S. A.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Ryckebusch, J.; Sabatié, F.; Sabourov, K.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Simionatto, S.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Spraker, M.; Stavinsky, A.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strauch, S.; Taiuti, M.; Taylor, S.; Tedeschi, D. J.; Thoma, U.; Thompson, R.; Tkabladze, A.; Todor, L.; Tur, C.; Ungaro, M.; Vineyard, M. F.; Vlassov, A. V.; Wang, K.; Weinstein, L. B.; Weller, H.; Weygand, D. P.; Whisnant, C. S.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zana, L.; Zhang, B.; CLAS Collaboration

2005-02-01

Single spin azimuthal asymmetries A were measured at Jefferson Lab using 2.2 and 4.4 GeV longitudinally polarised electrons incident on 4He and 12C targets in the CLAS detector. A is related to the imaginary part of the longitudinal-transverse interference and in quasifree nucleon knockout it provides an unambiguous signature for final state interactions (FSI). Experimental values of A were found to be below 5%, typically |A|⩽3% for data with good statistical precision. Optical model in eikonal approximation (OMEA) and relativistic multiple-scattering Glauber approximation (RMSGA) calculations are shown to be consistent with the measured asymmetries.

The Inherent Asymmetry of DNA Replication.

PubMed

Snedeker, Jonathan; Wooten, Matthew; Chen, Xin

2017-10-06

Semiconservative DNA replication has provided an elegant solution to the fundamental problem of how life is able to proliferate in a way that allows cells, organisms, and populations to survive and replicate many times over. Somewhat lost, however, in our admiration for this mechanism is an appreciation for the asymmetries that occur in the process of DNA replication. As we discuss in this review, these asymmetries arise as a consequence of the structure of the DNA molecule and the enzymatic mechanism of DNA synthesis. Increasing evidence suggests that asymmetries in DNA replication are able to play a central role in the processes of adaptation and evolution by shaping the mutagenic landscape of cells. Additionally, in eukaryotes, recent work has demonstrated that the inherent asymmetries in DNA replication may play an important role in the process of chromatin replication. As chromatin plays an essential role in defining cell identity, asymmetries generated during the process of DNA replication may play critical roles in cell fate decisions related to patterning and development.

Note: Eddy current displacement sensors independent of target conductivity.

PubMed

Wang, Hongbo; Li, Wei; Feng, Zhihua

2015-01-01

Eddy current sensors (ECSs) are widely used for non-contact displacement measurement. In this note, the quantitative error of an ECS caused by target conductivity was analyzed using a complex image method. The response curves (L-x) of the ECS with different targets were similar and could be overlapped by shifting the curves on x direction with √2δ/2. Both finite element analysis and experiments match well with the theoretical analysis, which indicates that the measured error of high precision ECSs caused by target conductivity can be completely eliminated, and the ECSs can measure different materials precisely without calibration.

Cosmic microwave background power asymmetry from non-Gaussian modulation.

PubMed

Schmidt, Fabian; Hui, Lam

2013-01-04

Non-Gaussianity in the inflationary perturbations can couple observable scales to modes of much longer wavelength (even superhorizon), leaving as a signature a large-angle modulation of the observed cosmic microwave background power spectrum. This provides an alternative origin for a power asymmetry that is otherwise often ascribed to a breaking of statistical isotropy. The non-Gaussian modulation effect can be significant even for typical ~10(-5) perturbations while respecting current constraints on non-Gaussianity if the squeezed limit of the bispectrum is sufficiently infrared divergent. Just such a strongly infrared-divergent bispectrum has been claimed for inflation models with a non-Bunch-Davies initial state, for instance. Upper limits on the observed cosmic microwave background power asymmetry place stringent constraints on the duration of inflation in such models.

Accessing the Elastic Form-Factors of the $Delta(1232)$ Using the Beam-Normal Asymmetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dalton, Mark M.

2016-08-01

The beam-normal single-spin asymmetry,more » $$B_n$$, exists in the scattering of high energy electrons, polarized transverse to their direction of motion, from nuclear targets. To first order, this asymmetry is caused by the interference of the one-photon exchange amplitude with the imaginary part of the two-photon exchange amplitude. Measurements of $$B_n$$, for the production of a $$\\Delta(1232)$$ resonance from a proton target, will soon become available from the Qweak experiment at Jefferson Lab and the A4 experiment at Mainz. The imaginary part of two-photon exchange allows only intermediate states that are on-shell, including the $$\\Delta$$ itself. Therefore such data is sensitive to $$\\gamma\\Delta\\Delta$$, the elastic form-factors of the $$\\Delta$$. This article will introduce the form-factors of the $$\\Delta$$, discuss what might be learned about the elastic form-factors from these new data, describe ongoing efforts in calculation and measurement, and outline the possibility of future measurements.« less

Poloidal asymmetries in edge transport barriersa)

NASA Astrophysics Data System (ADS)

Churchill, R. M.; Theiler, C.; Lipschultz, B.; Hutchinson, I. H.; Reinke, M. L.; Whyte, D.; Hughes, J. W.; Catto, P.; Landreman, M.; Ernst, D.; Chang, C. S.; Hager, R.; Hubbard, A.; Ennever, P.; Walk, J. R.

2015-05-01

Measurements of impurities in Alcator C-Mod indicate that in the pedestal region, significant poloidal asymmetries can exist in the impurity density, ion temperature, and main ion density. In light of the observation that ion temperature and electrostatic potential are not constant on a flux surface [Theiler et al., Nucl. Fusion 54, 083017 (2014)], a technique based on total pressure conservation to align profiles measured at separate poloidal locations is presented and applied. Gyrokinetic neoclassical simulations with XGCa support the observed large poloidal variations in ion temperature and density, and that the total pressure is approximately constant on a flux surface. With the updated alignment technique, the observed in-out asymmetry in impurity density is reduced from previous publishing [Churchill et al., Nucl. Fusion 53, 122002 (2013)], but remains substantial ( n z , H / n z , L ˜ 6 ). Candidate asymmetry drivers are explored, showing that neither non-uniform impurity sources nor localized fluctuation-driven transport are able to explain satisfactorily the impurity density asymmetry. Since impurity density asymmetries are only present in plasmas with strong electron density gradients, and radial transport timescales become comparable to parallel transport timescales in the pedestal region, it is suggested that global transport effects relating to the strong electron density gradients in the pedestal are the main driver for the pedestal in-out impurity density asymmetry.

TMD evolution of the Sivers asymmetry

NASA Astrophysics Data System (ADS)

Boer, Daniël

2013-09-01

The energy scale dependence of the Sivers asymmetry in semi-inclusive deep inelastic scattering is studied numerically within the framework of TMD factorization that was put forward in 2011. The comparison to previous results in the literature shows that the treatment of next-to-leading logarithmic effects is important for the fall-off of the Sivers asymmetry with energy in the measurable regime. The TMD factorization based approach indicates that the peak of the Sivers asymmetry falls off with energy scale Q to good approximation as 1/Q0.7, somewhat faster than found previously based on the first TMD factorization expressions by Collins and Soper in 1981. It is found that the peak of the asymmetry moves rather slowly towards higher transverse momentum values as Q increases, which may be due to the absence of perturbative tails of the TMDs in the presented treatments. We conclude that the behavior of the peak of the asymmetry as a function of energy and transverse momentum allows for valuable tests of the TMD formalism and the considered approximations. To confront the TMD approach with experiment, high energy experimental data from an Electron-Ion Collider is required. Note that in B01/B09 the Gaussian width of the Sivers TMD appears in the asymmetry expressions, because of the derivative in f1T⊥ ' a(x;Q0).

Measurement of the target current by inductive probe during laser interaction on terawatt laser system PALS.

PubMed

Cikhardt, J; Krása, J; De Marco, M; Pfeifer, M; Velyhan, A; Krouský, E; Cikhardtová, B; Klír, D; Rezáč, K; Ullschmied, J; Skála, J; Kubeš, P; Kravárik, J

2014-10-01

Measurements of the return-current flowing through a solid target irradiated with the sub-nanosecond kJ-class Prague Asterix Laser System is reported. A new inductive target probe was developed which allows us measuring the target current derivative in a kA/ns range. The dependences of the target current on the laser pulse energy for cooper, graphite, and polyethylene targets are reported. The experiment shows that the target current is proportional to the deposited laser energy and is strongly affected by the shot-to-shot fluctuations. The corresponding maximum target charge exceeded a value of 10 μC. A return-current dependence of the electromagnetic pulse produced by the laser-target interaction is presented.

Spin asymmetries for vector boson production in polarized p + p collisions

DOE PAGES

Huang, Jin; Kang, Zhong-Bo; Vitev, Ivan; ...

2016-01-28

We study the cross section for vector boson (W ±/Z 0/γ more » $$\\star$$) production in polarized nucleon-nucleon collisions for low transverse momentum of the observed vector boson. For the case where one measures the transverse momentum and azimuthal angle of the vector bosons, we present the cross sections and the associated spin asymmetries in terms of transverse momentum dependent parton distribution functions (TMDs) at tree level within the TMD factorization formalism. To assess the feasibility of experimental measurements, we estimate the spin asymmetries forW ±/Z 0 boson production in polarized proton-proton collisions at the Relativistic Heavy Ion Collider by using current knowledge of the relevant TMDs. Here, we find that some of these asymmetries can be sizable if the suppression effect from TMD evolution is not too strong. The W program at RHIC can, thus, test and constrain spin theory by providing unique information on the universality properties of TMDs, TMD evolution, and the nucleon structure. For example, the single transverse spin asymmetries could be used to probe the well-known Sivers function f$$⊥q\\atop{1T}$$, as well as the transversal helicity distribution g$$q\\atop{1T}$$ via the parity-violating nature of W production.« less

The Oft-Neglected Role of Parietal EEG Asymmetry and Risk for Major Depressive Disorder

PubMed Central

Stewart, Jennifer L.; Towers, David N.; Coan, James A.; Allen, John J.B.

2010-01-01

Relatively less right parietal activity may reflect reduced arousal and signify risk for major depressive disorder (MDD). Inconsistent findings with parietal electroencephalographic (EEG) asymmetry, however, suggest issues such as anxiety comorbidity and sex differences have yet to be resolved. Resting parietal EEG asymmetry was assessed in 306 individuals (31% male) with (n = 143) and without (n = 163) a DSM-IV diagnosis of lifetime MDD and no comorbid anxiety disorders. Past MDD+ women displayed relatively less right parietal activity than current MDD+ and MDD- women, replicating prior work. Recent caffeine intake, an index of arousal, moderated the relationship between depression and EEG asymmetry for women and men. Findings suggest that sex differences and arousal should be examined in studies of depression and regional brain activity. PMID:20525011

Exchange asymmetry in experimental settings

Treesearch

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

2015-01-01

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

Nodal signalling and asymmetry of the nervous system

PubMed Central

Signore, Iskra A.; Palma, Karina

2016-01-01

The role of Nodal signalling in nervous system asymmetry is still poorly understood. Here, we review and discuss how asymmetric Nodal signalling controls the ontogeny of nervous system asymmetry using a comparative developmental perspective. A detailed analysis of asymmetry in ascidians and fishes reveals a critical context-dependency of Nodal function and emphasizes that bilaterally paired and midline-unpaired structures/organs behave as different entities. We propose a conceptual framework to dissect the developmental function of Nodal as asymmetry inducer and laterality modulator in the nervous system, which can be used to study other types of body and visceral organ asymmetries. Using insights from developmental biology, we also present novel evolutionary hypotheses on how Nodal led the evolution of directional asymmetry in the brain, with a particular focus on the epithalamus. We intend this paper to provide a synthesis on how Nodal signalling controls left–right asymmetry of the nervous system. This article is part of the themed issue ‘Provocative questions in left–right asymmetry’. PMID:27821531

Stochastic left–right neuronal asymmetry in Caenorhabditis elegans

PubMed Central

Alqadah, Amel; Hsieh, Yi-Wen; Xiong, Rui

2016-01-01

Left–right asymmetry in the nervous system is observed across species. Defects in left–right cerebral asymmetry are linked to several neurological diseases, but the molecular mechanisms underlying brain asymmetry in vertebrates are still not very well understood. The Caenorhabditis elegans left and right amphid wing ‘C’ (AWC) olfactory neurons communicate through intercellular calcium signalling in a transient embryonic gap junction neural network to specify two asymmetric subtypes, AWCOFF (default) and AWCON (induced), in a stochastic manner. Here, we highlight the molecular mechanisms that establish and maintain stochastic AWC asymmetry. As the components of the AWC asymmetry pathway are highly conserved, insights from the model organism C. elegans may provide a window onto how brain asymmetry develops in humans. This article is part of the themed issue ‘Provocative questions in left–right asymmetry’. PMID:27821536

New Molecular Targets of Anticancer Therapy - Current Status and Perspectives.

PubMed

Zajac, Marianna; Muszalska, Izabela; Jelinska, Anna

2016-01-01

Molecularly targeted anticancer therapy involves the use of drugs or other substances affecting specific molecular targets that play a part in the development, progression and spread of a given neoplasm. By contrast, the majority of classical chemotherapeutics act on all rapidly proliferating cells, both healthy and cancerous ones. Target anticancer drugs are designed to achieve a particular aim and they usually act cytostatically, not cytotoxically like classical chemotherapeutics. At present, more than 300 biological molecular targets have been identified. The proteins involved in cellular metabolism include (among others) receptor proteins, signal transduction proteins, mRNA thread matrix synthesis proteins participating in neoplastic transformation, cell cycle control proteins, functional and structural proteins. The receptor proteins that are targeted by currently used anticancer drugs comprise the epithelial growth factor receptor (EGFR), platelet-derived growth factor receptor (PDGFR) and vascular endothelial growth factor receptor(VEGFR). Target anticancer drugs may affect extracellular receptor domains (antibodies) or intracellular receptor domains (tyrosine kinase inhibitors). The blocking of the mRNA thread containing information about the structure of oncogenes (signal transduction proteins) is another molecular target of anticancer drugs. That type of treatment, referred to as antisense therapy, is in clinical trials. When the synthesis of genetic material is disturbed, in most cases the passage to the next cycle phase is blocked. The key proteins responsible for the blockage are cyclines and cycline- dependent kinases (CDK). Clinical trials are focused on natural and synthetic substances capable of blocking various CDKs. The paper discusses the molecular targets and chemical structure of target anticancer drugs that have been approved for and currently applied in antineoplastic therapy together with indications and contraindications for their

Permeability Asymmetry in Composite Porous Ceramic Membranes

NASA Astrophysics Data System (ADS)

Kurcharov, I. M.; Laguntsov, N. I.; Uvarov, V. I.; Kurchatova, O. V.

The results from the investigation of transport characteristics and gas transport asymmetry in bilayer composite membranes are submitted. These membranes are produced by SHS method. Asymmetric effect and hysteresis of permeability in nanoporous membranes are detected. It's shown, that permeability ratio (asymmetry value of permeability) increases up to several times. The asymmetry of permeability usually decreases monotonically with the pressure decrease.

Bessel Weighted Asymmetries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avakian, Harut; Gamberg, Leonard; Rossi, Patrizia

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

Validity and sensitivity of the longitudinal asymmetry index to detect gait asymmetry using Microsoft Kinect data.

PubMed

Auvinet, E; Multon, F; Manning, V; Meunier, J; Cobb, J P

2017-01-01

Gait asymmetry information is a key point in disease screening and follow-up. Constant Relative Phase (CRP) has been used to quantify within-stride asymmetry index, which requires noise-free and accurate motion capture, which is difficult to obtain in clinical settings. This study explores a new index, the Longitudinal Asymmetry Index (ILong) which is derived using data from a low-cost depth camera (Kinect). ILong is based on depth images averaged over several gait cycles, rather than derived joint positions or angles. This study aims to evaluate (1) the validity of CRP computed with Kinect, (2) the validity and sensitivity of ILong for measuring gait asymmetry based solely on data provided by a depth camera, (3) the clinical applicability of a posteriorly mounted camera system to avoid occlusion caused by the standard front-fitted treadmill consoles and (4) the number of strides needed to reliably calculate ILong. The gait of 15 subjects was recorded concurrently with a marker-based system (MBS) and Kinect, and asymmetry was artificially reproduced by introducing a 5cm sole attached to one foot. CRP computed with Kinect was not reliable. ILong detected this disturbed gait reliably and could be computed from a posteriorly placed Kinect without loss of validity. A minimum of five strides was needed to achieve a correlation coefficient of 0.9 between standard MBS and low-cost depth camera based ILong. ILong provides a clinically pragmatic method for measuring gait asymmetry, with application for improved patient care through enhanced disease, screening, diagnosis and monitoring. Copyright © 2016. Published by Elsevier B.V.

Magnetic reconnection in Earth's magnetotail: Energy conversion and its earthward-tailward asymmetry

NASA Astrophysics Data System (ADS)

Lu, San; Pritchett, P. L.; Angelopoulos, V.; Artemyev, A. V.

2018-01-01

Magnetic reconnection, a fundamental plasma process, releases magnetic energy and converts it to particle energy, by accelerating and heating ions and electrons. This energy conversion plays an important role in the Earth's magnetotail. A two-dimensional particle-in-cell simulation is performed to study such a conversion in a magnetotail topology, one with a nonzero Bz, and the energy conversion is found to be more efficient in the earthward outflow than in the tailward outflow. Such earthward-tailward asymmetry is manifested not only in j .E but also in Poynting flux, Hall electromagnetic fields, bulk kinetic energy flux, enthalpy flux, heat flux, bulk acceleration, heating, and suprathermal particle energization, all of which are more prevalent on the earthward side. Such asymmetries are consistent with spacecraft observations reported in the literature. Our study shows that in the magnetotail, most of the energy converted by reconnection flows predominantly toward the Earth and has the potential of being geoeffective, rather than being expelled to the solar wind by the tailward flow. The energy conversion asymmetry arises from the presence of the non-zero normal magnetic field, the stronger lobe magnetic field, and the stronger cross-tail current earthward of the reconnection site in the pre-reconnecting thin current sheet.

First measurement of the double spin asymmetry in (-->)e(-->)p-->e(prime)pi(+)n in the resonance region.

PubMed

De Vita, R; Anghinolfi, M; Burkert, V D; Dodge, G E; Minehart, R; Taiuti, M; Weller, H; Adams, G; Amaryan, M J; Anciant, E; Armstrong, D S; Asavapibhop, B; Asryan, G; Audit, G; Auger, T; Avakian, H; Bagdasaryan, H; Ball, J P; Barrow, S; Battaglieri, M; Beard, K; Bektasoglu, M; Bianchi, N; Biselli, A S; Boiarinov, S; Bonner, B E; Bosted, P; Bouchigny, S; Branford, D; Brooks, W K; Bueltmann, S; Calarco, J R; Capitani, G P; Carman, D S; Carnahan, B; Cazes, A; Ciciani, L; Cole, P L; Coleman, A; Connelly, J; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Cummings, J P; De Sanctis, E; Degtyarenko, P V; Demirchyan, R; Denizli, H; Dennis, L; Dharmawardane, K V; Dhuga, K S; Djalali, C; Doughty, D; Dragovitsch, P; Dugger, M; Dytman, S; Eckhause, M; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Empl, A; Farhi, L; Fatemi, R; Feuerbach, R J; Ficenec, J; Forest, T A; Frolov, V; Funsten, H; Gaff, S J; Gai, M; Garçon, M; Gavalian, G; Gilad, S; Gilfoyle, G P; Giovanetti, K L; Girard, P; Golovatch, E; Griffioen, K; Guidal, M; Guillo, M; Gyurjyan, V; Hadjidakis, C; Hancock, D; Hardie, J; Heddle, D; Heimberg, P; Hersman, F W; Hicks, K; Hicks, R S; Holtrop, M; Hu, J; Hyde-Wright, C E; Ishkanov, B S; Ito, M M; Jenkins, D; Joo, K; Kelley, J H; Kellie, J D; Khandaker, M; Kim, K Y; Kim, K; Kim, W; Klein, A; Klein, F J; Klusman, M; Kossov, M; Kramer, L H; Kuang, Y; Kuhn, S E; Lachniet, J; Laget, J M; Lawrence, D; Li, Ji; Livingston, K; Longhi, A; Loukachine, K; Lucas, M; Major, W; Manak, J J; Marchand, C; McAleer, S; McCarthy, J; McNabb, J W C; Mecking, B A; Mestayer, M D; Meyer, C A; Mikhailov, K; Mirazita, M; Miskimen, R; Mokeev, V; Muccifora, V; Mueller, J; Mutchler, G S; Napolitano, J; Nelson, S O; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niyazov, R A; Opper, A K; O'Rielly, G V; Osipenko, M; Park, K; Pasyuk, E; Peterson, G; Philips, S A; Pivnyuk, N; Pocanic, D; Pogorelko, O; Polli, E; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Qin, L M; Raue, B A; Reolon, A R; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Rock, S; Ronchetti, F; Rossi, P; Rowntree, D; Rubin, P D; Sabatié, F; Sabourov, K; Salgado, C; Sapunenko, V; Sargsyan, M; Schumacher, R A; Serov, V S; Shafi, A; Sharabian, Y G; Shaw, J; Skabelin, A V; Smith, E S; Smith, T; Smith, L C; Sober, D I; Sorrell, L; Spraker, M; Stavinsky, A; Stepanyan, S; Stoler, P; Strakovsky, I I; Taylor, S; Tedeschi, D J; Thompson, R; Todor, L; Ungaro, M; Vineyard, M F; Vlassov, A V; Wang, K; Weinstein, L B; Weisberg, A; Weygand, D P; Whisnant, C S; Wolin, E; Yegneswaran, A; Yun, J; Zhang, B; Zhao, J; Zhou, Z

2002-02-25

The double spin asymmetry in the (-->)e(-->)p --> e(prime)pi(+)n reaction has been measured for the first time in the resonance region for four-momentum transfer Q2 = 0.35-1.5 GeV(2). Data were taken at Jefferson Lab with the CLAS detector using a 2.6 GeV polarized electron beam incident on a polarized solid NH3 target. Comparison with predictions of phenomenological models shows strong sensitivity to resonance contributions. Helicity-1/2 transitions are found to be dominant in the second and third resonance regions. The measured asymmetry is consistent with a faster rise with Q(2) of the helicity asymmetry A1 for the F(15)(1680) resonance than expected from the analysis of the unpolarized data.

Asymmetry identification in rigid rotating bodies—Theory and experiment

NASA Astrophysics Data System (ADS)

Bucher, Izhak; Shomer, Ofer

2013-12-01

Asymmetry and anisotropy are important parameters in rotating devices that can cause instability; indicate a manufacturing defect or a developing fault. The present paper discusses an identification method capable of detecting minute levels of asymmetry by exploiting the unique dynamics of parametric excitation caused by asymmetry and rotation. The detection relies on rigid body dynamics without resorting to nonlinear vibration analysis, and the natural dynamics of elastically supported systems is exploited in order to increase the sensitivity to asymmetry. It is possible to isolate asymmetry from other rotation-induced phenomena like unbalance. An asymmetry detection machine which was built in the laboratory demonstrates the method alongside theoretical analysis.

Maternal Frontal EEG Asymmetry and Chronic Stressors Moderate the Link between Child Conduct Problems and Maternal Negativity

PubMed Central

Chen, Nan; Bell, Martha Ann; Deater-Deckard, Kirby

2016-01-01

Frontal EEG asymmetry is associated with individual differences in positive/negative emotionality and approach/avoidance tendencies. The current study examined the moderating role of maternal resting frontal EEG asymmetry on the link between child behavior problems and maternal harsh parenting, within the context of differing degrees of chronic family stressors (father unemployment, single parenthood, caring for multiple children, and household chaos). The sample included 121 mother-child pairs. Results showed that stressors and frontal EEG asymmetry together moderated the link. Child problem behaviors were moderately associated with greater maternal negativity for mothers with right frontal asymmetry, or mothers who experienced more stressors. However, no association existed between child behavior problems and maternal negativity for mothers with few stressors and left frontal asymmetry. The findings implicate transactions between household stress and a psychophysiological indicator of maternal emotional reactivity and mothers’ approach/avoidance tendencies, in the etiology of parental negativity toward challenging child behaviors. PMID:27853348

Obesity: Current and potential pharmacotherapeutics and targets.

PubMed

Narayanaswami, Vidya; Dwoskin, Linda P

2017-02-01

Obesity is a global epidemic that contributes to a number of health complications including cardiovascular disease, type 2 diabetes, cancer and neuropsychiatric disorders. Pharmacotherapeutic strategies to treat obesity are urgently needed. Research over the past two decades has increased substantially our knowledge of central and peripheral mechanisms underlying homeostatic energy balance. Homeostatic mechanisms involve multiple components including neuronal circuits, some originating in hypothalamus and brain stem, as well as peripherally-derived satiety, hunger and adiposity signals that modulate neural activity and regulate eating behavior. Dysregulation of one or more of these homeostatic components results in obesity. Coincident with obesity, reward mechanisms that regulate hedonic aspects of food intake override the homeostatic regulation of eating. In addition to functional interactions between homeostatic and reward systems in the regulation of food intake, homeostatic signals have the ability to alter vulnerability to drug abuse. Regarding the treatment of obesity, pharmacological monotherapies primarily focus on a single protein target. FDA-approved monotherapy options include phentermine (Adipex-P®), orlistat (Xenical®), lorcaserin (Belviq®) and liraglutide (Saxenda®). However, monotherapies have limited efficacy, in part due to the recruitment of alternate and counter-regulatory pathways. Consequently, a multi-target approach may provide greater benefit. Recently, two combination products have been approved by the FDA to treat obesity, including phentermine/topiramate (Qsymia®) and naltrexone/bupropion (Contrave®). The current review provides an overview of homeostatic and reward mechanisms that regulate energy balance, potential therapeutic targets for obesity and current treatment options, including some candidate therapeutics in clinical development. Finally, challenges in anti-obesity drug development are discussed. Copyright © 2016 Elsevier

Obesity: Current and Potential Pharmacotherapeutics and Targets

PubMed Central

Narayanaswami, Vidya; Dwoskin, Linda P.

2016-01-01

Obesity is a global epidemic that contributes to a number of health complications including cardiovascular disease, type 2 diabetes, cancer and neuropsychiatric disorders. Pharmacotherapeutic strategies to treat obesity are urgently needed. Research over the past two decades has increased substantially our knowledge of central and peripheral mechanisms underlying homeostatic energy balance. Homeostatic mechanisms involve multiple components including neuronal circuits, some originating in hypothalamus and brain stem, as well as peripherally-derived satiety, hunger and adiposity signals that modulate neural activity and regulate eating behavior. Dysregulation of one or more of these homeostatic components results in obesity. Coincident with obesity, reward mechanisms that regulate hedonic aspects of food intake override the homeostatic regulation of eating. In addition to functional interactions between homeostatic and reward systems in the regulation of food intake, homeostatic signals have the ability to alter vulnerability to drug abuse. Regarding the treatment of obesity, pharmacological monotherapies primarily focus on a single protein target. FDA-approved monotherapy options include phentermine (Adipex-P®), orlistat (Xenical®), lorcaserin (Belviq®) and liraglutide (Saxenda®). However, monotherapies have limited efficacy, in part due to the recruitment of alternate and counter-regulatory pathways. Consequently, a multi-target approach may provide greater benefit. Recently, two combination products have been approved by the FDA to treat obesity, including phentermine/topiramate (Qsymia®) and naltrexone/bupropion (Contrave®). The current review provides an overview of homeostatic and reward mechanisms that regulate energy balance, potential therapeutic targets for obesity and current treatment options, including some candidate therapeutics in clinical development. Finally, challenges in anti-obesity drug development are discussed. PMID:27773782

Induced static asymmetry of the pelvis is associated with functional asymmetry of the lumbo-pelvo-hip complex.

PubMed

Gnat, Rafał; Saulicz, Edward

2008-03-01

This study evaluates the hypothesis that triggering and eliminating induced static pelvic asymmetry (SPA) may be followed by immediate change in functional asymmetry of the lumbo-pelvo-hip complex. Repeated measures experimental design with 2 levels of independent variable, that is, induced SPA triggered and induced SPA eliminated, was implemented. Three series of measurements were performed, that is, baseline, after triggering SPA, and after eliminating SPA. A group of 84 subjects with no initial symptoms of SPA was studied. Different forms of mechanical stimulation were applied aiming to induce SPA, and the 2 manual stretching-manipulating techniques were performed aiming to eliminate it. A hand inclinometer was used to measure SPA in standing posture. Selected ranges of motion of the hip joints and lumbar spine were used to depict functional asymmetry of the lumbo-pelvo-hip complex. The functional asymmetry indices for individual movements were calculated. Repeated measures design of analysis of variance, dependent data Student t test, and linear Pearson's correlation test were used. Assessment of the SPA showed its significant increase between baseline and series 2 measurements, with a subsequent significant decrease between series 2 and series 3 measurements. Values of the functional asymmetry indices changed accordingly, that is, they increased significantly between series 1 and series 2 and had returned to their initial level in series 3 measurements. Induced SPA shows considerable association with functional asymmetry of the lumbo-pelvo-hip complex.

Matter-antimatter asymmetry induced by a running vacuum coupling

NASA Astrophysics Data System (ADS)

Lima, J. A. S.; Singleton, D.

2017-12-01

We show that a CP-violating interaction induced by a derivative coupling between the running vacuum and a non-conserving baryon current may dynamically break CPT and trigger baryogenesis through an effective chemical potential. By assuming a non-singular class of running vacuum cosmologies which provides a complete cosmic history (from an early inflationary de Sitter stage to the present day quasi-de Sitter acceleration), it is found that an acceptable baryon asymmetry is generated for many different choices of the model parameters. It is interesting that the same ingredient (running vacuum energy density) addresses several open cosmological questions/problems: avoids the initial singularity, provides a smooth exit for primordial inflation, alleviates both the coincidence and the cosmological constant problems, and, finally, is also capable of explaining the generation of matter-antimatter asymmetry in the very early Universe.

Autophoretic locomotion from geometric asymmetry.

PubMed

Michelin, Sébastien; Lauga, Eric

2015-02-01

Among the few methods which have been proposed to create small-scale swimmers, those relying on self-phoretic mechanisms present an interesting design challenge in that chemical gradients are required to generate net propulsion. Building on recent work, we propose that asymmetries in geometry are sufficient to induce chemical gradients and swimming. We illustrate this idea using two different calculations. We first calculate exactly the self-propulsion speed of a system composed of two spheres of unequal sizes but identically chemically homogeneous. We then consider arbitrary, small-amplitude, shape deformations of a chemically homogeneous sphere, and calculate asymptotically the self-propulsion velocity induced by the shape asymmetries. Our results demonstrate how geometric asymmetries can be tuned to induce large locomotion speeds without the need of chemical patterning.

Current trends in the use of liposomes for tumor targeting

PubMed Central

Deshpande, Pranali P; Biswas, Swati; Torchilin, Vladimir P

2013-01-01

The use of liposomes for drug delivery began early in the history of pharmaceutical nanocarriers. These nanosized, lipid bilayered vesicles have become popular as drug delivery systems owing to their efficiency, biocompatibility, nonimmunogenicity, enhanced solubility of chemotherapeutic agents and their ability to encapsulate a wide array of drugs. Passive and ligand-mediated active targeting promote tumor specificity with diminished adverse off-target effects. The current field of liposomes focuses on both clinical and diagnostic applications. Recent efforts have concentrated on the development of multifunctional liposomes that target cells and cellular organelles with a single delivery system. This review discusses the recent advances in liposome research in tumor targeting. PMID:23914966

Prevalence of arytenoid asymmetry in relation to vocal symptoms.

PubMed

Hamdan, A-L; Nassar, J; Ashkar, J; Sibai, A

2011-03-01

(1) To assess the prevalence of arytenoid asymmetry during adduction, and (2) to correlate arytenoid asymmetry with vocal symptoms. The medical records and video recordings of 116 patients who presented to the voice clinic were reviewed for the presence of arytenoid asymmetry, as regards sharpening of the aryepiglottic fold angle and altered positioning of the cuneiform and corniculate cartilages. There were 61 males and 55 females, with a mean age of 39 years and a standard deviation of 15 years. Almost one-third had a history of reflux, 25 per cent had a history of smoking and 9.6 per cent had a history of allergy. Hoarseness was the most common symptom, occurring in 42.2 per cent of patients, followed by vocal fatigue (25 per cent) and inability to project the voice. The most common type of asymmetry was corniculate asymmetry, present in 27.6 per cent of the cases and accounting for 74.39 per cent of cases. This was followed by cuneiform cartilage asymmetry, present in 15.5 per cent of cases. There was no correlation between arytenoid asymmetry and vocal symptoms, except for vocal fatigue (p = 0.038). The prevalence of arytenoid asymmetry during adduction is common. The presence of vocal symptoms such as hoarseness, breathiness, inability to project the voice and straining does not generally seem to correlate with the prevalence of arytenoid asymmetry. However, subjects with vocal fatigue are more likely to have cuneiform asymmetry.

A test of local Lorentz invariance with Compton scattering asymmetry

DOE PAGES

Mohanmurthy, Prajwal; Narayan, Amrendra; Dutta, Dipangkar

2016-12-14

Here, we report on a measurement of the constancy and anisotropy of the speed of light relative to the electrons in photon-electron scattering. We also used the Compton scattering asymmetry measured by the new Compton polarimeter in Hall~C at Jefferson Lab to test for deviations from unity of the vacuum refractive index (more » $n$). For photon energies in the range of 9 - 46 MeV, we obtain a new limit of $$1-n < 1.4 \\times 10^{-8}$$. In addition, the absence of sidereal variation over the six month period of the measurement constrains any anisotropies in the speed of light. These constitute the first study of Lorentz invariance using Compton asymmetry. Within the minimal standard model extension framework, our result yield limits on the photon and electron coefficients $$\\tilde{\\kappa}_{0^+}^{YZ}, c_{TX}, \\tilde{\\kappa}_{0^+}^{ZX}$$, and $$c_{TY}$$. Though, these limits are several orders of magnitude larger than the current best limits, they demonstrate the feasibility of using Compton asymmetry for tests of Lorentz invariance. For future parity violating electron scattering experiments at Jefferson Lab we will use higher energy electrons enabling better constraints.« less

Anomalies and asymmetries in quark-gluon matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teryaev, O. V., E-mail: teryaev@theor.jinr.ru

The manifestations of axial anomaly and related effects in heavy-ion collisions are considered. Special role is played by various asymmetries. The azimuthal correlational asymmetries of neutron pairs at NICA/FAIR energy range may probe the global rotation of strongly interacting matter. The conductivity is related to the angular asymmetries of dilepton pairs. The strong magnetic field generated in heavy-ion collisions leads to the excess of soft dileptons flying predominantly in the scattering plane.

Geometric asymmetry driven Janus micromotors

NASA Astrophysics Data System (ADS)

Zhao, Guanjia; Pumera, Martin

2014-09-01

The production and application of nano-/micromotors is of great importance. In order for the motors to work, asymmetry in their chemical composition or physical geometry must be present if no external asymmetric field is applied. In this paper, we present a ``coconut'' micromotor made of platinum through the partial or complete etching of the silica templates. It was shown that although both the inner and outer surfaces are made of the same material (Pt), motion of the structure can be observed as the convex surface is capable of generating oxygen bubbles. This finding shows that not only the chemical asymmetry of the micromotor, but also its geometric asymmetry can lead to fast propulsion of the motor. Moreover, a considerably higher velocity can be seen for partially etched coconut structures than the velocities of Janus or fully etched, shell-like motors. These findings will have great importance on the design of future micromotors.The production and application of nano-/micromotors is of great importance. In order for the motors to work, asymmetry in their chemical composition or physical geometry must be present if no external asymmetric field is applied. In this paper, we present a ``coconut'' micromotor made of platinum through the partial or complete etching of the silica templates. It was shown that although both the inner and outer surfaces are made of the same material (Pt), motion of the structure can be observed as the convex surface is capable of generating oxygen bubbles. This finding shows that not only the chemical asymmetry of the micromotor, but also its geometric asymmetry can lead to fast propulsion of the motor. Moreover, a considerably higher velocity can be seen for partially etched coconut structures than the velocities of Janus or fully etched, shell-like motors. These findings will have great importance on the design of future micromotors. Electronic supplementary information (ESI) available: Additional SEM images, data analysis, Videos S

Prevalence of lateral ventricle asymmetry in brain MRI studies of neurologically normal dogs and dogs with idiopathic epilepsy.

PubMed

Pivetta, Mauro; De Risio, Luisa; Newton, Richard; Dennis, Ruth

2013-01-01

Asymmetry of the cerebral lateral ventricles is a common finding in cross-sectional imaging of otherwise normal canine brains and has been assumed to be incidental. The purpose of this retrospective study was to compare the prevalence of ventricular asymmetry in brain MRI studies of normal dogs and dogs with idiopathic epilepsy. Brain MRI archives were searched for 100 neurologically normal dogs (Group 1) and 100 dogs with idiopathic epilepsy (Group 2). For each dog, asymmetry of the lateral ventricles was subjectively classified as absent, mild, moderate, and severe based on a consensus of two observers who were unaware of group status. Ventricular areas were measured from transverse T1W images at the level of the interthalamic adhesion. An asymmetry ratio was calculated as the ratio of the larger to smaller ventricular transverse area. There was excellent agreement between subjective assessments of ventricular asymmetry and quantitative assessments using asymmetry ratios (k = 0.995). The prevalence of asymmetry was 38% in Group 1 dogs and 44% in Group 2 dogs. Assymmetry was scored as mild in the majority of Group 2 dogs. There was no significant association between presence/absence and degree of ventricular asymmetry vs. dog group, age, gender, or skull conformation. Findings from the current study supported previously published assumptions that asymmetry of the lateral cerebral ventricles is an incidental finding in MRI studies of the canine brain. © 2013 Veterinary Radiology & Ultrasound.

A ryanodine receptor-dependent Ca(i)(2+) asymmetry at Hensen's node mediates avian lateral identity.

PubMed

Garic-Stankovic, Ana; Hernandez, Marcos; Flentke, George R; Zile, Maija H; Smith, Susan M

2008-10-01

In mouse, the establishment of left-right (LR) asymmetry requires intracellular calcium (Ca(i)(2+)) enrichment on the left of the node. The use of Ca(i)(2+) asymmetry by other vertebrates, and its origins and relationship to other laterality effectors are largely unknown. Additionally, the architecture of Hensen's node raises doubts as to whether Ca(i)(2+) asymmetry is a broadly conserved mechanism to achieve laterality. We report here that the avian embryo uses a left-side enriched Ca(i)(2+) asymmetry across Hensen's node to govern its lateral identity. Elevated Ca(i)(2+) was first detected along the anterior node at early HH4, and its emergence and left-side enrichment by HH5 required both ryanodine receptor (RyR) activity and extracellular calcium, implicating calcium-induced calcium release (CICR) as the novel source of the Ca(i)(2+). Targeted manipulation of node Ca(i)(2+) randomized heart laterality and affected nodal expression. Bifurcation of the Ca(i)(2+) field by the emerging prechordal plate may permit the independent regulation of LR Ca(i)(2+) levels. To the left of the node, RyR/CICR and H(+)V-ATPase activity sustained elevated Ca(i)(2+). On the right, Ca(i)(2+) levels were actively repressed through the activities of H(+)K(+) ATPase and serotonin-dependent signaling, thus identifying a novel mechanism for the known effects of serotonin on laterality. Vitamin A-deficient quail have a high incidence of situs inversus hearts and had a reversed calcium asymmetry. Thus, Ca(i)(2+) asymmetry across the node represents a more broadly conserved mechanism for laterality among amniotes than had been previously believed.

Introduction to provocative questions in left-right asymmetry.

PubMed

Levin, Michael; Klar, Amar J S; Ramsdell, Ann F

2016-12-19

Left-right asymmetry is a phenomenon that has a broad appeal-to anatomists, developmental biologists and evolutionary biologists-because it is a morphological feature of organisms that spans scales of size and levels of organization, from unicellular protists, to vertebrate organs, to social behaviour. Here, we highlight a number of important aspects of asymmetry that encompass several areas of biology-cell-level, physiological, genetic, anatomical and evolutionary components-and that are based on research conducted in diverse model systems, ranging from single cells to invertebrates to human developmental disorders. Together, the contributions in this issue reveal a heretofore-unsuspected variety in asymmetry mechanisms, including ancient chirality elements that could underlie a much more universal basis to asymmetry development, and provide much fodder for thought with far reaching implications in biomedical, developmental, evolutionary and synthetic biology. The new emerging theme of binary cell-fate choice, promoted by asymmetric cell division of a deterministic cell, has focused on investigating asymmetry mechanisms functioning at the single cell level. These include cytoskeleton and DNA chain asymmetry-mechanisms that are amplified and coordinated with those employed for the determination of the anterior-posterior and dorsal-ventral axes of the embryo.This article is part of the themed issue 'Provocative questions in left-right asymmetry'. © 2016 The Author(s).

Measurement of the Parity-Violating Asymmetry in Deep Inelastic Scattering at JLab 6 GeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Diancheng

2013-12-01

The parity-violating asymmetry in deep inelastic scattering (PVDIS) offers us a useful tool to study the weak neutral couplings and the hadronic structure of the nucleon, and provides high precision tests on the Standard Model. During the 6 GeV PVDIS experiment at the Thomas Jefferson National Accelerator Facility, the parity-violating asymmetries A{sub PV} of a polarized electron beam scattering off an unpolarized deuteron target in the deep inelastic scattering region were precisely measured at two Q 2 values of 1.1 and 1.9 (GeV/c) 2. The asymmetry at Q 2=1.9 (GeV/c) 2 can be used to extract the weak coupling combinationmore » 2C 2u - C 2d, assuming the higher twist effect is small. The extracted result from this measurement is in good agreement with the Standard Model prediction, and improves the precision by a factor of five over previous data. In addition, combining the asymmetries at both Q 2 values provides us extra knowledge on the higher twist effects. The parity violation asymmetries in the resonance region were also measured during this experiment. These results are the first A PV data in the resonance region beyond the Δ (1232). They provide evidence that the quark hadron duality works for A PV at the (10-15)% level, and set constraints on nucleon resonance models that are commonly used for background calculations to other parity-violating electron scattering measurements.« less

Current Drug Targets in Obesity Pharmacotherapy - A Review.

PubMed

Bhat, Sangeeta P; Sharma, Arun

2017-01-01

Obesity, an impending global pandemic, is not being effectively controlled by current measures such as lifestyle modifications, bariatric surgery or available medications. Its toll on health and economy compels us to look for more effective measures. Fortunately, the advances in biology and molecular technology have been in our favour for delineating new pathways in the pathophysiology of obesity and have led to subsequent development of new drug targets. Development of antiobesity drugs has often been riddled with problems in the past. Some of the recently approved drugs for pharmacotherapy of obesity have been lorcaserin, phentermine/topiramate and naltrexone/ bupropion combinations. Several promising new targets are currently being evaluated, such as amylin analogues (pramlintide, davalintide), leptin analogues (metreleptin), GLP-1 analogues (exenatide, liraglutide, TTP-054), MC4R agonists (RM-493), oxyntomodulin analogues, neuropeptide Y antagonists (velneperit), cannabinoid type-1 receptor blockers (AM-6545), MetAP2 inhibitors (beloranib), lipase inhibitors (cetilistat) and anti-obesity vaccines (ghrelin, somatostatin, Ad36). Many of these groups of drugs act as "satiety signals" while others act by antagonizing orexigenic signals, increasing fat utilisation and decreasing absorption of fats. Since these targets act through various pathways, the possibility of combined use of two or more classes of these drugs unlocks numerous therapeutic avenues. Hence, the dream of personalized management of obesity might be growing closer to reality. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Extraction of the neutron electric form factor from measurements of inclusive double spin asymmetries

NASA Astrophysics Data System (ADS)

Sulkosky, V.; Jin, G.; Long, E.; Zhang, Y.-W.; Mihovilovic, M.; Kelleher, A.; Anderson, B.; Higinbotham, D. W.; Širca, S.; Allada, K.; Annand, J. R. M.; Averett, T.; Bertozzi, W.; Boeglin, W.; Bradshaw, P.; Camsonne, A.; Canan, M.; Cates, G. D.; Chen, C.; Chen, J.-P.; Chudakov, E.; De Leo, R.; Deng, X.; Deur, A.; Dutta, C.; El Fassi, L.; Flay, D.; Frullani, S.; Garibaldi, F.; Gao, H.; Gilad, S.; Gilman, R.; Glamazdin, O.; Golge, S.; Gomez, J.; Hansen, J.-O.; Holmstrom, T.; Huang, J.; Ibrahim, H.; de Jager, C. W.; Jensen, E.; Jiang, X.; Jones, M.; Kang, H.; Katich, J.; Khanal, H. P.; King, P.; Korsch, W.; LeRose, J.; Lindgren, R.; Lu, H.-J.; Luo, W.; Markowitz, P.; Meekins, D.; Meziane, M.; Michaels, R.; Moffit, B.; Monaghan, P.; Muangma, N.; Nanda, S.; Norum, B. E.; Pan, K.; Parno, D.; Piasetzky, E.; Posik, M.; Punjabi, V.; Puckett, A. J. R.; Qian, X.; Qiang, Y.; Qui, X.; Riordan, S.; Saha, A.; Sawatzky, B.; Shabestari, M.; Shahinyan, A.; Shoenrock, B.; John, J. St.; Subedi, R.; Tobias, W. A.; Tireman, W.; Urciuoli, G. M.; Wang, D.; Wang, K.; Wang, Y.; Watson, J.; Wojtsekhowski, B.; Ye, Z.; Zhan, X.; Zhang, Y.; Zheng, X.; Zhao, B.; Zhu, L.; Jefferson Lab Hall A Collaboration

2017-12-01

Background: Measurements of the neutron charge form factor, GEn, are challenging because the neutron has no net charge. In addition, measurements of the neutron form factors must use nuclear targets which require accurately accounting for nuclear effects. Extracting GEn with different targets and techniques provides an important test of our handling of these effects. Purpose: The goal of the measurement was to use an inclusive asymmetry measurement technique to extract the neutron charge form factor at a four-momentum transfer of 1 (GeV/c ) 2 . This technique has very different systematic uncertainties than traditional exclusive measurements and thus serves as an independent check of whether nuclear effects have been taken into account correctly. Method: The inclusive quasielastic reaction 3He ⃗(e ⃗,e') was measured at Jefferson Laboratory. The neutron electric form factor, GEn, was extracted at Q2=0.98 (GeV/c ) 2 from ratios of electron-polarization asymmetries measured for two orthogonal target spin orientations. This Q2 is high enough that the sensitivity to GEn is not overwhelmed by the neutron magnetic contribution, and yet low enough that explicit neutron detection is not required to suppress pion production. Results: The neutron electric form factor, GEn, was determined to be 0.0414 ±0.0077 (stat)±0.0022 (syst) , providing the first high-precision inclusive extraction of the neutron's charge form factor. Conclusions: The use of the inclusive quasielastic 3He ⃗(e ⃗,e') with a four-momentum transfer near 1 (GeV/c ) 2 has been used to provide a unique measurement of GEn. This new result provides a systematically independent validation of the exclusive extraction technique results and implies that the nuclear corrections are understood. This is contrary to the proton form factor where asymmetry and differential cross section measurements have been shown to have large systematic differences.

Model-Dependent Constraint on Quark Total Angular Momentum Based on the Transverse Target-spin Asymmetry Measured in Deeply Virtual Compton Scattering at HERMES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nowak, Wolf-Dieter

Results are reported on the transverse target-spin asymmetry (TTSA) associated with deeply virtual Compton scattering on the proton. The data have been accumulated in the years 2002-2004 by the HERMES experiment at DESY, in which the HERA 27.6 GeV e+ beam scattered on a transversely polarized hydrogen target. Two azimuthal amplitudes of the TTSA appearing to LO in 1/Q and {alpha}s, A{sub UT}{sup sin({phi}-{phi}{sub S})cos{phi}} and A{sub UT}{sup cos({phi} -{phi}{sub S})sin{phi}}, are given as a function of -t,xB,Q2 in the kinematic range |t| < 0.7 GeV2, 0.03 < xB < 0.35 and 1 < Q2 < 10 GeV2. The firstmore » amplitude is found to be sensitive to the generalized parton distribution (GPD) E of the proton, which can be parameterized in a GPD model through quark total angular momentum Jq(q = u, d). Within the context of this model, a constraint in the (Ju,Jd) plane is obtained from HERMES TTSA data.« less

Anatomical landmark asymmetry assessment in the lumbar spine and pelvis: a review of reliability.

PubMed

Stovall, Bradley Alan; Kumar, Shrawan

2010-01-01

The purpose of this article is to review current research investigating the reliability of bony anatomical landmark positional asymmetry assessment in the lumbar spine and pelvis, to determine the agreement on findings between authors, and to explore future directions in the area to address the significant issues. The databases MEDLINE, CINAHL, AMED, MANTIS, Academic Search Complete, and Web of Knowledge were searched. A total of 23 articles were identified and reviewed, 10 of which met the inclusion criteria. For these 10 articles, the average interexaminer reliability for bony anatomical landmark positional asymmetry assessment was slightly above chance for all landmarks except medial malleolus, which had fair reliability. Interexaminer reliability on average was less than intraexaminer reliability (anterior superior iliac spine, k = 0.128/0.414; posterior superior iliac spine, k = 0.092/0.371). All interexaminer reliability averages were below values of clinical significance. From the current literature review, bony anatomical landmark positional asymmetry assessment in the lumbar spine and pelvis has not been demonstrated to be a reliable assessment method. However, there are unexplored factors that, after standardization, may improve reliability and further the understanding of musculoskeletal palpatory examination.

Three-dimensional assessment of facial asymmetry: A systematic review.

PubMed

Akhil, Gopi; Senthil Kumar, Kullampalayam Palanisamy; Raja, Subramani; Janardhanan, Kumaresan

2015-08-01

For patients with facial asymmetry, complete and precise diagnosis, and surgical treatments to correct the underlying cause of the asymmetry are significant. Conventional diagnostic radiographs (submento-vertex projections, posteroanterior radiography) have limitations in asymmetry diagnosis due to two-dimensional assessments of three-dimensional (3D) images. The advent of 3D images has greatly reduced the magnification and projection errors that are common in conventional radiographs making it as a precise diagnostic aid for assessment of facial asymmetry. Thus, this article attempts to review the newly introduced 3D tools in the diagnosis of more complex facial asymmetries.

Entanglement asymmetry for boosted black branes and the bound

NASA Astrophysics Data System (ADS)

Mishra, Rohit; Singh, Harvendra

2017-06-01

We study the effects of asymmetry in the entanglement thermodynamics of CFT subsystems. It is found that “boosted” Dp-brane backgrounds give rise to the first law of the entanglement thermodynamics where the CFT pressure asymmetry plays a decisive role in the entanglement. Two different strip like subsystems, one parallel to the boost and the other perpendicular, are studied in the perturbative regime Tthermal ≪ TE. We mainly seek to quantify this entanglement asymmetry as a ratio of the first-order entanglement entropies of the excitations. We discuss the AdS-wave backgrounds at zero temperature having maximum asymmetry from where a bound on entanglement asymmetry is obtained. The entanglement asymmetry reduces as we switch on finite temperature in the CFT while it is maximum at zero temperature.

Replication-associated mutational asymmetry in the human genome.

PubMed

Chen, Chun-Long; Duquenne, Lauranne; Audit, Benjamin; Guilbaud, Guillaume; Rappailles, Aurélien; Baker, Antoine; Huvet, Maxime; d'Aubenton-Carafa, Yves; Hyrien, Olivier; Arneodo, Alain; Thermes, Claude

2011-08-01

During evolution, mutations occur at rates that can differ between the two DNA strands. In the human genome, nucleotide substitutions occur at different rates on the transcribed and non-transcribed strands that may result from transcription-coupled repair. These mutational asymmetries generate transcription-associated compositional skews. To date, the existence of such asymmetries associated with replication has not yet been established. Here, we compute the nucleotide substitution matrices around replication initiation zones identified as sharp peaks in replication timing profiles and associated with abrupt jumps in the compositional skew profile. We show that the substitution matrices computed in these regions fully explain the jumps in the compositional skew profile when crossing initiation zones. In intergenic regions, we observe mutational asymmetries measured as differences between complementary substitution rates; their sign changes when crossing initiation zones. These mutational asymmetries are unlikely to result from cryptic transcription but can be explained by a model based on replication errors and strand-biased repair. In transcribed regions, mutational asymmetries associated with replication superimpose on the previously described mutational asymmetries associated with transcription. We separate the substitution asymmetries associated with both mechanisms, which allows us to determine for the first time in eukaryotes, the mutational asymmetries associated with replication and to reevaluate those associated with transcription. Replication-associated mutational asymmetry may result from unequal rates of complementary base misincorporation by the DNA polymerases coupled with DNA mismatch repair (MMR) acting with different efficiencies on the leading and lagging strands. Replication, acting in germ line cells during long evolutionary times, contributed equally with transcription to produce the present abrupt jumps in the compositional skew. These results

Regional facial asymmetries and attractiveness of the face.

PubMed

Kaipainen, Anu E; Sieber, Kevin R; Nada, Rania M; Maal, Thomas J; Katsaros, Christos; Fudalej, Piotr S

2016-12-01

Facial attractiveness is an important factor in our social interactions. It is still not entirely clear which factors influence the attractiveness of a face and facial asymmetry appears to play a certain role. The aim of the present study was to assess the association between facial attractiveness and regional facial asymmetries evaluated on three-dimensional (3D) images. 3D facial images of 59 (23 male, 36 female) young adult patients (age 16-25 years) before orthodontic treatment were evaluated for asymmetry. The same 3D images were presented to 12 lay judges who rated the attractiveness of each subject on a 100mm visual analogue scale. Reliability of the method was assessed with Bland-Altman plots and Cronbach's alpha coefficient. All subjects showed a certain amount of asymmetry in all regions of the face; most asymmetry was found in the chin and cheek areas and less in the lip, nose and forehead areas. No statistically significant differences in regional facial asymmetries were found between male and female subjects (P > 0.05). Regression analyses demonstrated that the judgement of facial attractiveness was not influenced by absolute regional facial asymmetries when gender, facial width-to-height ratio and type of malocclusion were controlled (P > 0.05). A potential limitation of the study could be that other biologic and cultural factors influencing the perception of facial attractiveness were not controlled for. A small amount of asymmetry was present in all subjects assessed in this study, and asymmetry of this magnitude may not influence the assessment of facial attractiveness. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Mercury exposure may influence fluctuating asymmetry in waterbirds

USGS Publications Warehouse

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

2017-01-01

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

Asymmetry of the Brain: Development and Implications.

PubMed

Duboc, Véronique; Dufourcq, Pascale; Blader, Patrick; Roussigné, Myriam

2015-01-01

Although the left and right hemispheres of our brains develop with a high degree of symmetry at both the anatomical and functional levels, it has become clear that subtle structural differences exist between the two sides and that each is dominant in processing specific cognitive tasks. As the result of evolutionary conservation or convergence, lateralization of the brain is found in both vertebrates and invertebrates, suggesting that it provides significant fitness for animal life. This widespread feature of hemispheric specialization has allowed the emergence of model systems to study its development and, in some cases, to link anatomical asymmetries to brain function and behavior. Here, we present some of what is known about brain asymmetry in humans and model organisms as well as what is known about the impact of environmental and genetic factors on brain asymmetry development. We specifically highlight the progress made in understanding the development of epithalamic asymmetries in zebrafish and how this model provides an exciting opportunity to address brain asymmetry at different levels of complexity.

Lack of visual field asymmetries for spatial cueing in reading parafoveal Chinese characters.

PubMed

Luo, Chunming; Dell'Acqua, Roberto; Proctor, Robert W; Li, Xingshan

2015-12-01

In two experiments, we investigated whether visual field (VF) asymmetries of spatial cueing are involved in reading parafoveal Chinese characters. These characters are different from linearly arranged alphabetic words in that they are logograms that are confined to a constant, square-shaped area and are composed of only a few radicals. We observed a cueing effect, but it did not vary with the VF in which the Chinese character was presented, regardless of whether the cue validity (the ratio of validly to invalidly cued targets) was 1:1 or 7:3. These results suggest that VF asymmetries of spatial cueing do not affect the reading of parafoveal Chinese characters, contrary to the reading of alphabetic words. The mechanisms of spatial attention in reading parafoveal English-like words and Chinese characters are discussed.

Spectral and temporal characteristics of target current and electromagnetic pulse induced by nanosecond laser ablation

NASA Astrophysics Data System (ADS)

Krása, J.; De Marco, M.; Cikhardt, J.; Pfeifer, M.; Velyhan, A.; Klír, D.; Řezáč, K.; Limpouch, J.; Krouský, E.; Dostál, J.; Ullschmied, J.; Dudžák, R.

2017-06-01

The current balancing the target charging and the emission of transient electromagnetic pulses (EMP) driven by the interaction of a focused 1.315 μm iodine 300 ps PALS laser with metallic and plastic targets were measured with the use of inductive probes. It is experimentally proven that the duration of return target currents and EMPs is much longer than the duration of laser-target interaction. The laser-produced plasma is active after the laser-target interaction. During this phase, the target acts as a virtual cathode and the plasma-target interface expands. A double exponential function is used in order to obtain the temporal characteristics of EMP. The rise time of EMPs fluctuates in the range up to a few tens of nanoseconds. Frequency spectra of EMP and target currents are modified by resonant frequencies of the interaction chamber.

Relationship between asymmetry of quiet standing balance control and walking post-stroke.

PubMed

Hendrickson, Janna; Patterson, Kara K; Inness, Elizabeth L; McIlroy, William E; Mansfield, Avril

2014-01-01

Spatial and temporal gait asymmetry is common after stroke. Such asymmetric gait is inefficient, can contribute to instability and may lead to musculoskeletal injury. However, understanding of the determinants of such gait asymmetry remains incomplete. The current study is focused on revealing if there is a link between asymmetry during the control of standing balance and asymmetry during walking. This study involved review of data from 94 individuals with stroke referred to a gait and balance clinic. Participants completed three tests: (1) walking at their usual pace; (2) quiet standing; and (3) standing with maximal loading of the paretic side. A pressure sensitive mat recorded placement and timing of each footfall during walking. Standing tests were completed on two force plates to evaluate symmetry of weight bearing and contribution of each limb to balance control. Multiple regression was conducted to determine the relationships between symmetry during standing and swing time, stance time, and step length symmetry during walking. Symmetry of antero-posterior balance control and weight bearing were related to swing time and step length symmetry during walking. Weight-bearing symmetry, weight-bearing capacity, and symmetry of antero-posterior balance control were related to stance time symmetry. These associations were independent of underlying lower limb impairment. The results support the hypothesis that impaired ability of the paretic limb to control balance may contribute to gait asymmetry post-stroke. Such work suggests that rehabilitation strategies that increase the contribution of the paretic limb to standing balance control may increase symmetry of walking post-stroke. Copyright © 2013 Elsevier B.V. All rights reserved.

Study of C P -violating charge asymmetries of single muons and like-sign dimuons in p p ¯ collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abazov, V. M.; Abbott, B.; Acharya, B. S.

2014-01-01

We measure the inclusive single muon charge asymmetry and the like-sign dimuon charge asymmetry inmore » $$p \\bar{p}$$ collisions using the full data set of 10.4 fb$$^{-1}$$ collected with the D0 detector at the Fermilab Tevatron. The standard model predictions of the charge asymmetries induced by CP violation are small in magnitude compared to the current experimental precision, so non-zero measurements could indicate new sources of CP violation. The measurements differ from the standard model predictions of CP violation in these asymmetries with a significance of 3.6 standard deviations. These results are interpreted in a framework of $B$ meson mixing within the CKM formalism to measure the relative width difference $$\\dgg$$ between the mass eigenstates of the $$\\Bd$$ meson system, and the semileptonic charge asymmetries $$\\asld$$ and $$\\asls$$ of $$\\Bd$$ and $$\\Bs$$ mesons respectively.« less

Asymmetries in the spectral density of an interaction-quenched Luttinger liquid

NASA Astrophysics Data System (ADS)

Calzona, A.; Gambetta, F. M.; Carrega, M.; Cavaliere, F.; Sassetti, M.

2018-03-01

The spectral density of an interaction-quenched one-dimensional system is investigated. Both direct and inverse quench protocols are considered and it is found that the former leads to stronger effects on the spectral density with respect to the latter. Such asymmetry is directly reflected on transport properties of the system, namely the charge and energy current flowing to the system from a tunnel coupled biased probe. In particular, the injection of particles from the probe to the right-moving channel of the system is considered. The resulting fractionalization phenomena are strongly affected by the quench protocol and display asymmetries in the case of direct and inverse quench. Transport properties therefore emerge as natural probes for the observation of this quench-induced behavior.

Fluctuating asymmetry and stress in a medieval Nubian population.

PubMed

Deleon, Valerie B

2007-04-01

Fluctuating asymmetry is commonly used as a bioindicator of developmental stress. This study addresses asymmetry under nutritional/systemic stress in the human craniofacial skeleton and its utility as an indicator of developmental instability. Crania from the diachronic Christian cemeteries at Kulubnarti (Sudanese Nubia) were chosen as a model for nutrition/systemic stress. Previous studies indicate that individuals from the Early Christian cemetery were subjected to greater developmental stress when compared with individuals from the Late Christian cemetery. Therefore, crania from the Early Christian cemetery should display a greater magnitude of fluctuating asymmetry than crania from the Late Christian cemetery. Thirty adult crania of comparable age and sex were selected from each population. Landmark coordinates were digitized in two separate trials and averaged to minimize error. Euclidean distance matrix analysis (EDMA) was used to measure and compare the magnitude of fluctuating asymmetry in each sample. Results indicate that crania from the Early Christian cemetery display greater amounts of fluctuating asymmetry than those from the Late Christian cemetery, as predicted. The degree of fluctuating asymmetry for each linear distance is highly correlated between the cemeteries, suggesting that all humans may share common patterns of fluctuating asymmetry in the skull. In contrast, there is little correlation between magnitude of fluctuating asymmetry and length of linear distance, between-subject variability, or measurement error. These results support the hypothesis that poor nutrition/systemic stress increases developmental instability in the human skull and that increased fluctuating asymmetry constitutes morphological evidence of this stress.

Cerberus-Nodal-Lefty-Pitx signaling cascade controls left-right asymmetry in amphioxus.

PubMed

Li, Guang; Liu, Xian; Xing, Chaofan; Zhang, Huayang; Shimeld, Sebastian M; Wang, Yiquan

2017-04-04

Many bilaterally symmetrical animals develop genetically programmed left-right asymmetries. In vertebrates, this process is under the control of Nodal signaling, which is restricted to the left side by Nodal antagonists Cerberus and Lefty. Amphioxus, the earliest diverging chordate lineage, has profound left-right asymmetry as a larva. We show that Cerberus , Nodal , Lefty , and their target transcription factor Pitx are sequentially activated in amphioxus embryos. We then address their function by transcription activator-like effector nucleases (TALEN)-based knockout and heat-shock promoter (HSP)-driven overexpression. Knockout of Cerberus leads to ectopic right-sided expression of Nodal , Lefty , and Pitx , whereas overexpression of Cerberus represses their left-sided expression. Overexpression of Nodal in turn represses Cerberus and activates Lefty and Pitx ectopically on the right side. We also show Lefty represses Nodal , whereas Pitx activates Nodal These data combine in a model in which Cerberus determines whether the left-sided gene expression cassette is activated or repressed. These regulatory steps are essential for normal left-right asymmetry to develop, as when they are disrupted embryos may instead form two phenotypic left sides or two phenotypic right sides. Our study shows the regulatory cassette controlling left-right asymmetry was in place in the ancestor of amphioxus and vertebrates. This includes the Nodal inhibitors Cerberus and Lefty, both of which operate in feedback loops with Nodal and combine to establish asymmetric Pitx expression. Cerberus and Lefty are missing from most invertebrate lineages, marking this mechanism as an innovation in the lineage leading to modern chordates.

Transverse single-spin asymmetries: Challenges and recent progress

DOE PAGES

Metz, Andreas; Pitonyak, Daniel; Schafer, Andreas; ...

2014-11-25

In this study, transverse single-spin asymmetries are among the most intriguing observables in hadronic physics. Though such asymmetries were already measured for the first time about four decades ago, their origin is still under debate. Here we consider transverse single-spin asymmetries in semi-inclusive lepton–nucleon scattering, in nucleon–nucleon scattering, and in inclusive lepton–nucleon scattering. It is argued that, according to recent work, the single-spin asymmetries for those three processes may be simultaneously described in perturbative QCD, where the re-scattering of the active partons plays a crucial role. A comparison of single-spin asymmetries in different reactions can also shed light on themore » universality of transverse momentum dependent parton correlation functions. In particular, we discuss what existing data may tell us about the predicted process dependence of the Sivers function.« less

The Visual Hemifield Asymmetry in the Spatial Blink during Singleton Search and Feature Search

ERIC Educational Resources Information Center

Burnham, Bryan R.; Rozell, Cassandra A.; Kasper, Alex; Bianco, Nicole E.; Delliturri, Antony

2011-01-01

The present study examined a visual field asymmetry in the contingent capture of attention that was previously observed by Du and Abrams (2010). In our first experiment, color singleton distractors that matched the color of a to-be-detected target produced a stronger capture of attention when they appeared in the left visual hemifield than in the…

Effects of longitudinal asymmetry in heavy-ion collisions

NASA Astrophysics Data System (ADS)

Raniwala, Rashmi; Raniwala, Sudhir; Loizides, Constantin

2018-02-01

In collisions of identical nuclei at a given impact parameter, the number of nucleons participating in the overlap region of each nucleus can be unequal due to nuclear density fluctuations. The asymmetry due to the unequal number of participating nucleons, referred to as longitudinal asymmetry, causes a shift in the center-of-mass rapidity of the participant zone. The information of the event asymmetry allows us to isolate and study the effect of longitudinal asymmetry on rapidity distribution of final state particles. In a Monte Carlo Glauber model the average rapidity shift is found to be almost linearly related to the asymmetry. Using toy models, as well as Monte Carlo data for Pb-Pb collisions at 2.76 TeV generated with hijing, two different versions of ampt and dpmjet models, we demonstrate that the effect of asymmetry on final state rapidity distribution can be quantitatively related to the average rapidity shift via a third-order polynomial with a dominantly linear term. The coefficients of the polynomial are proportional to the rapidity shift with the dependence being sensitive to the details of the rapidity distribution. Experimental estimates of the spectator asymmetry through the measurement of spectator nucleons in a zero-degree calorimeter may hence be used to further constrain the initial conditions in ultra-relativistic heavy-ion collisions.

Asymmetric SOL Current in Vertically Displaced Plasma

NASA Astrophysics Data System (ADS)

Cabrera, J. D.; Navratil, G. A.; Hanson, J. M.

2017-10-01

Experiments at the DIII-D tokamak demonstrate a non-monotonic relationship between measured scrape-off layer (SOL) currents and vertical displacement event (VDE) rates with SOL currents becoming largely n=1 dominant as plasma is displaced by the plasma control system (PCS) at faster rates. The DIII-D PCS is used to displace the magnetic axis 10x slower than the intrinsic growth time of similar instabilities in lower single-null plasmas. Low order (n <=2) mode decomposition is done on toroidally spaced current monitors to attain measures of asymmetry in SOL current. Normalized to peak n=0 response, a 2-4x increase is seen in peak n=1 response in plasmas displaced by the PCS versus previous VDE instabilities observed when vertical control is disabled. Previous inquiry shows VDE asymmetry characterized by SOL current fraction and geometric parameters of tokamak plasmas. We note that, of plasmas displaced by the PCS, short displacement time scales near the limit of the PCS temporal control appear to result in larger n=1/n=2 asymmetries. Work supported under USDOE Cooperative Agreement DE-FC02-04ER54698 and DE-FG02-04ER54761.

Interference of fission amplitudes of neutron resonances and T-odd asymmetry for various prescission third particles in the ternary fission of nuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kadmensky, S. G., E-mail: kadmensky@phys.vsu.ru; Bunakov, V. E.; Kadmensky, S. S.

Differential cross sections for reactions of the true ternary fission of nuclei that was induced by cold polarized neutrons were constructed with allowance of the effect that Coriolis interaction and the interference between fission amplitudes of neutron resonances excited in fissile nuclei upon incidentneutron capture by target nuclei exerted on angular distributions of prescission third particles (alpha particles, neutrons, or photons). It is shown that T -odd TRI- and ROT-type asymmetries for prescission alpha particles are associated with, respectively, the odd and even components of the Coriolis interaction-perturbed amplitude of angular distributions of particles belonging to the types indicated above.more » These asymmetries have angular distributions differing from each other and stemming from a nontrivial dependence of these components on the neutron-resonance spins J{sub s} and their projections K{sub s} onto the symmetry axis of the nucleus involved. It is shown that angular distributions of prescission photons and neutrons from reactions of the ternary fission of nuclei that is induced by cold polarized neutrons are determined by the effect of Coriolis forces exclusively. Therefore, the emerging T-odd asymmetries have a character of a ROT-type asymmetry and are universal for all target nuclei.« less

Measurement of Deeply Virtual Compton Scattering with a Polarized-Proton Target

NASA Astrophysics Data System (ADS)

Chen, S.; Avakian, H.; Burkert, V. D.; Eugenio, P.; Adams, G.; Amarian, M.; Ambrozewicz, P.; Anghinolfi, M.; Asryan, G.; Bagdasaryan, H.; Baillie, N.; Ball, J. P.; Baltzell, N. A.; Barrow, S.; Batourine, V.; Battaglieri, M.; Beard, K.; Bedlinskiy, I.; Bektasoglu, M.; Bellis, M.; Benmouna, N.; Berman, B. L.; Biselli, A. S.; Bonner, B. E.; Bouchigny, S.; Boiarinov, S.; Bosted, P.; Bradford, R.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Butuceanu, C.; Calarco, J. R.; Careccia, S. L.; Carman, D. S.; Carnahan, B.; Cazes, A.; Cole, P. L.; Collins, P.; Coltharp, P.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Crede, V.; Cummings, J. P.; Masi, R. De; Devita, R.; Sanctis, E. De; Degtyarenko, P. V.; Denizli, H.; Dennis, L.; Deur, A.; Dharmawardane, K. V.; Dhuga, K. S.; Djalali, C.; Dodge, G. E.; Donnelly, J.; Doughty, D.; Dugger, M.; Dytman, S.; Dzyubak, O. P.; Egiyan, H.; Egiyan, K. S.; Fassi, L. El; Elouadrhiri, L.; Fatemi, R.; Fedotov, G.; Feldman, G.; Feuerbach, R. J.; Forest, T. A.; Funsten, H.; Garçon, M.; Gavalian, G.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Golovatch, E.; Gonenc, A.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hafidi, K.; Hakobyan, H.; Hakobyan, R. S.; Hardie, J.; Heddle, D.; Hersman, F. W.; Hicks, K.; Hleiqawi, I.; Holtrop, M.; Huertas, M.; Hyde-Wright, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Ito, M. M.; Jenkins, D.; Jo, H. S.; Joo, K.; Juengst, H. G.; Keith, C.; Kellie, J. D.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kubarovsky, V.; Kuhn, J.; Kuhn, S. E.; Kuleshov, S. V.; Lachniet, J.; Laget, J. M.; Langheinrich, J.; Lawrence, D.; Li, Ji; Lima, A. C. S.; Livingston, K.; Lu, H.; Lukashin, K.; MacCormick, M.; Markov, N.; McAleer, S.; McKinnon, B.; McNabb, J. W. C.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Mibe, T.; Mikhailov, K.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morand, L.; Morrow, S. A.; Moteabbed, M.; Mueller, J.; Mutchler, G. S.; Nadel-Turonski, P.; Napolitano, J.; Nasseripour, R.; Natasha, N.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Niczyporuk, B. B.; Niroula, M. R.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Paterson, C.; Philips, S. A.; Pierce, J.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Popa, I.; Pozdniakov, S.; Preedom, B. M.; Price, J. W.; Prok, Y.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Ronchetti, F.; Rosner, G.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabatié, F.; Salgado, C.; Santoro, J. P.; Sapunenko, V.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Shvedunov, N. V.; Skabelin, A. V.; Smith, E. S.; Smith, L. C.; Sober, D. I.; Stavinsky, A.; Stepanyan, S. S.; Stepanyan, S.; Stokes, B. E.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Suleiman, R.; Taiuti, M.; Tedeschi, D. J.; Thoma, U.; Tkabladze, A.; Tkachenko, S.; Todor, L.; Tur, C.; Ungaro, M.; Vanderhaeghen, M.; Vineyard, M. F.; Vlassov, A. V.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Williams, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Yun, J.; Zana, L.; Zhang, J.; Zhao, B.; Zhao, Z.

2006-08-01

The longitudinal target-spin asymmetry AUL for the exclusive electroproduction of high-energy photons was measured for the first time in ep→→e'pγ. The data have been accumulated at JLab with the CLAS spectrometer using 5.7 GeV electrons and a longitudinally polarized NH3 target. A significant azimuthal angular dependence was observed, resulting from the interference of the deeply virtual Compton scattering and Bethe-Heitler processes. The amplitude of the sin⁡ϕ moment is 0.252±0.042stat±0.020sys. Theoretical calculations are in good agreement with the magnitude and the kinematic dependence of the target-spin asymmetry, which is sensitive to the generalized parton distributions H˜ and H.

Examining the radiation drive asymmetries present in the high foot series of implosion experiments at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Pak, A.; Divol, L.; Kritcher, A. L.; Ma, T.; Ralph, J. E.; Bachmann, B.; Benedetti, L. R.; Casey, D. T.; Celliers, P. M.; Dewald, E. L.; Döppner, T.; Field, J. E.; Fratanduono, D. E.; Berzak Hopkins, L. F.; Izumi, N.; Khan, S. F.; Landen, O. L.; Kyrala, G. A.; LePape, S.; Millot, M.; Milovich, J. L.; Moore, A. S.; Nagel, S. R.; Park, H.-S.; Rygg, J. R.; Bradley, D. K.; Callahan, D. A.; Hinkel, D. E.; Hsing, W. W.; Hurricane, O. A.; Meezan, N. B.; Moody, J. D.; Patel, P.; Robey, H. F.; Schneider, M. B.; Town, R. P. J.; Edwards, M. J.

2017-05-01

This paper details and examines the origins of radiation drive asymmetries present during the initial High Foot implosion experiments. Such asymmetries are expected to reduce the stagnation pressure and the resulting yield of these experiments by several times. Analysis of reemission and dual axis shock timing experiments indicates that a flux asymmetry, with a P2/P0 amplitude that varies from -10% to -5%, is present during the first shock of the implosion. This first shock asymmetry can be corrected through adjustments to the laser cone fraction. A thin shell model and more detailed radiation hydrodynamic calculations indicate that an additional negative P2/P0 asymmetry during the second or portions of the third shock is required to reach the observed amount of asymmetry in the shape of the ablator at peak implosion velocity. In conjunction with symmetry data from the x-ray self emission produced at stagnation, these models also indicate that after the initially negative P2/P0 flux asymmetry, the capsule experiences a positive P2/P0 flux asymmetry that develops at or before ˜2 ns into the peak of the laser power. Here, direct evidence for this inference, using measurements of the x-ray emission produced by the lasers irradiating the hohlraum, is presented. These data indicate that the reduction in the transmitted inner laser cone energy results from impeded propagation through the plasma associated with the ablation of the capsule target. This paper also correlates measurements of the outer cone laser deposition location with variations in the observed x-ray self emission shape from experiments conducted with nominally the same input conditions.

Examining the radiation drive asymmetries present in the high foot series of implosion experiments at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pak, A.; Divol, L.; Kritcher, A. L.

This paper details and examines the origins of radiation drive asymmetries present during the initial High Foot implosion experiments. Such asymmetries are expected to reduce the stagnation pressure and the resulting yield of these experiments by several times. Analysis of reemission and dual axis shock timing experiments indicates that a flux asymmetry, with a P2/P0 amplitude that varies from -10 to -5 %, is present during the first shock of the implosion. This first shock asymmetry can be corrected through adjustments to the laser cone fraction. A thin shell model and more detailed radiation hydrodynamic calculations indicate that an additionalmore » negative P2/P0 asymmetry during the second or portions of the third shock is required to reach the observed amount of asymmetry in the shape of the ablator at peak implosion velocity. In conjunction with symmetry data from the x-ray self emission produced at stagnation, these models also indicate that after the initially negative P2/P0 flux asymmetry, the capsule experiences a positive P2/P0 flux asymmetry that develops at or before ~2 ns into the peak of the laser power. Here, direct evidence for this inference, using measurements of the x-ray emission produced by the lasers irradiating the hohlraum, is presented. This data indicates that the reduction in the transmitted inner laser cone energy results from impeded propagation through the plasma associated with the ablation of the capsule target. This paper also correlates measurements of the outer cone laser deposition location with variations in the observed x-ray self emission shape from experiments conducted with nominally the same input conditions.« less

Examining the radiation drive asymmetries present in the high foot series of implosion experiments at the National Ignition Facility

DOE PAGES

Pak, A.; Divol, L.; Kritcher, A. L.; ...

2017-03-24

This paper details and examines the origins of radiation drive asymmetries present during the initial High Foot implosion experiments. Such asymmetries are expected to reduce the stagnation pressure and the resulting yield of these experiments by several times. Analysis of reemission and dual axis shock timing experiments indicates that a flux asymmetry, with a P2/P0 amplitude that varies from -10 to -5 %, is present during the first shock of the implosion. This first shock asymmetry can be corrected through adjustments to the laser cone fraction. A thin shell model and more detailed radiation hydrodynamic calculations indicate that an additionalmore » negative P2/P0 asymmetry during the second or portions of the third shock is required to reach the observed amount of asymmetry in the shape of the ablator at peak implosion velocity. In conjunction with symmetry data from the x-ray self emission produced at stagnation, these models also indicate that after the initially negative P2/P0 flux asymmetry, the capsule experiences a positive P2/P0 flux asymmetry that develops at or before ~2 ns into the peak of the laser power. Here, direct evidence for this inference, using measurements of the x-ray emission produced by the lasers irradiating the hohlraum, is presented. This data indicates that the reduction in the transmitted inner laser cone energy results from impeded propagation through the plasma associated with the ablation of the capsule target. This paper also correlates measurements of the outer cone laser deposition location with variations in the observed x-ray self emission shape from experiments conducted with nominally the same input conditions.« less

Gait asymmetry: composite scores for mechanical analyses of sprint running.

PubMed

Exell, T A; Gittoes, M J R; Irwin, G; Kerwin, D G

2012-04-05

Gait asymmetry analyses are beneficial from clinical, coaching and technology perspectives. Quantifying overall athlete asymmetry would be useful in allowing comparisons between participants, or between asymmetry and other factors, such as sprint running performance. The aim of this study was to develop composite kinematic and kinetic asymmetry scores to quantify athlete asymmetry during maximal speed sprint running. Eight male sprint trained athletes (age 22±5 years, mass 74.0±8.7 kg and stature 1.79±0.07 m) participated in this study. Synchronised sagittal plane kinematic and kinetic data were collected via a CODA motion analysis system, synchronised to two Kistler force plates. Bilateral, lower limb data were collected during the maximal velocity phase of sprint running (velocity=9.05±0.37 ms(-1)). Kinematic and kinetic composite asymmetry scores were developed using the previously established symmetry angle for discrete variables associated with successful sprint performance and comparisons of continuous joint power data. Unlike previous studies quantifying gait asymmetry, the scores incorporated intra-limb variability by excluding variables from the composite scores that did not display significantly larger (p<0.05) asymmetry than intra-limb variability. The variables that contributed to the composite scores and the magnitude of asymmetry observed for each measure varied on an individual participant basis. The new composite scores indicated the inter-participant differences that exist in asymmetry during sprint running and may serve to allow comparisons between overall athlete asymmetry with other important factors such as performance. Copyright © 2012 Elsevier Ltd. All rights reserved.

Precise discussion of time-reversal asymmetries in B-meson decays

DOE PAGES

Morozumi, Takuya; Okane, Hideaki; Umeeda, Hiroyuki

2015-02-26

BaBar collaboration announced that they observed time reversal (T) asymmetry through B meson system. In the experiment, time dependencies of two distinctive processes, B_ →B¯ 0 and B¯ 0 → B_ (– expresses CP value) are compared with each other. In our study, we examine event number difference of these two processes. In contrast to the BaBar asymmetry, the asymmetry of events number includes the overall normalization difference for rates. Time dependence of the asymmetry is more general and it includes terms absent in one used by BaBar collaboration. Both of the BaBar asymmetry and ours are naively thought tomore » be T-odd since two processes compared are related with flipping time direction. We investigate the time reversal transformation property of our asymmetry. Using our notation, one can see that the asymmetry is not precisely a T-odd quantity, taking into account indirect CP and CPT violation of K meson systems. The effect of ϵK is extracted and gives rise to O(10 –3) contribution. The introduced parameters are invariant under rephasing of quarks so that the coefficients of our asymmetry are expressed as phase convention independent quantities. Some combinations of the asymmetry enable us to extract parameters for wrong sign decays of B d meson, CPT violation, etc. As a result, we also study the reason why the T-even terms are allowed to contribute to the asymmetry, and find that several conditions are needed for the asymmetry to be a T-odd quantity.« less

A voxel-based approach to gray matter asymmetries.

PubMed

Luders, E; Gaser, C; Jancke, L; Schlaug, G

2004-06-01

Voxel-based morphometry (VBM) was used to analyze gray matter (GM) asymmetries in a large sample (n = 60) of male and female professional musicians with and without absolute pitch (AP). We chose to examine these particular groups because previous studies using traditional region-of-interest (ROI) analyses have shown differences in hemispheric asymmetry related to AP and gender. Voxel-based methods may have advantages over traditional ROI-based methods since the analysis can be performed across the whole brain with minimal user bias. After determining that the VBM method was sufficiently sensitive for the detection of differences in GM asymmetries between groups, we found that male AP musicians were more leftward lateralized in the anterior region of the planum temporale (PT) than male non-AP musicians. This confirmed the results of previous studies using ROI-based methods that showed an association between PT asymmetry and the AP phenotype. We further observed that male non-AP musicians revealed an increased leftward GM asymmetry in the postcentral gyrus compared to female non-AP musicians, again corroborating results of a previously published study using ROI-based methods. By analyzing hemispheric GM differences across our entire sample, we were able to partially confirm findings of previous studies using traditional morphometric techniques, as well as more recent, voxel-based analyses. In addition, we found some unusually pronounced GM asymmetries in our musician sample not previously detected in subjects unselected for musical training. Since we were able to validate gender- and AP-related brain asymmetries previously described using traditional ROI-based morphometric techniques, the results of our analyses support the use of VBM for examinations of GM asymmetries.

A 3% Measurement of the Beam Normal Single Spin Asymmetry in Forward Angle Elastic Electron-Proton Scattering using the Qweak Setup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Waidyawansa, Dinayadura Buddhini

2013-08-01

The beam normal single spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable of the imaginary part of the two-photon exchange process. Moreover, it is a potential source of false asymmetry in parity violating electron scattering experiments. The Q{sub weak} experiment uses parity violating electron scattering to make a direct measurement of the weak charge of the proton. The targeted 4% measurement of the weak charge of the proton probes for parity violating new physics beyond the Standard Model. The beam normal single spin asymmetry at Q{sub weak} kinematics is at least threemore » orders of magnitude larger than 5 ppb precision of the parity violating asymmetry. To better understand this parity conserving background, the Q{sub weak} Collaboration has performed elastic scattering measurements with fully transversely polarized electron beam on the proton and aluminum. This dissertation presents the analysis of the 3% measurement (1.3% statistical and 2.6% systematic) of beam normal single spin asymmetry in electronproton scattering at a Q2 of 0.025 (GeV/c)2. It is the most precise existing measurement of beam normal single spin asymmetry available at the time. A measurement of this precision helps to improve the theoretical models on beam normal single spin asymmetry and thereby our understanding of the doubly virtual Compton scattering process.« less

Visuospatial Asymmetries Arise from Differences in the Onset Time of Perceptual Evidence Accumulation.

PubMed

Newman, Daniel P; Loughnane, Gerard M; Kelly, Simon P; O'Connell, Redmond G; Bellgrove, Mark A

2017-03-22

Healthy subjects tend to exhibit a bias of visual attention whereby left hemifield stimuli are processed more quickly and accurately than stimuli appearing in the right hemifield. It has long been held that this phenomenon arises from the dominant role of the right cerebral hemisphere in regulating attention. However, methods that would enable more precise understanding of the mechanisms underpinning visuospatial bias have remained elusive. We sought to finely trace the temporal evolution of spatial biases by leveraging a novel bilateral dot motion detection paradigm. In combination with electroencephalography, this paradigm enables researchers to isolate discrete neural signals reflecting the key neural processes needed for making these detection decisions. These include signals for spatial attention, early target selection, evidence accumulation, and motor preparation. Using this method, we established that three key neural markers accounted for unique between-subject variation in visuospatial bias: hemispheric asymmetry in posterior α power measured before target onset, which is related to the distribution of preparatory attention across the visual field; asymmetry in the peak latency of the early N2c target-selection signal; and, finally, asymmetry in the onset time of the subsequent neural evidence-accumulation process with earlier onsets for left hemifield targets. Our development of a single paradigm to dissociate distinct processing components that track the temporal evolution of spatial biases not only advances our understanding of the neural mechanisms underpinning normal visuospatial attention bias, but may also in the future aid differential diagnoses in disorders of spatial attention. SIGNIFICANCE STATEMENT The significance of this research is twofold. First, it shows that individual differences in how humans direct their attention between left and right space reflects physiological differences in how early the brain starts to accumulate evidence for

Asymmetry in power-law magnitude correlations.

PubMed

Podobnik, Boris; Horvatić, Davor; Tenenbaum, Joel N; Stanley, H Eugene

2009-07-01

Time series of increments can be created in a number of different ways from a variety of physical phenomena. For example, in the phenomenon of volatility clustering-well-known in finance-magnitudes of adjacent increments are correlated. Moreover, in some time series, magnitude correlations display asymmetry with respect to an increment's sign: the magnitude of |x_{i}| depends on the sign of the previous increment x_{i-1} . Here we define a model-independent test to measure the statistical significance of any observed asymmetry. We propose a simple stochastic process characterized by a an asymmetry parameter lambda and a method for estimating lambda . We illustrate both the test and process by analyzing physiological data.

Facial asymmetry quantitative evaluation in oculoauriculovertebral spectrum.

PubMed

Manara, Renzo; Schifano, Giovanni; Brotto, Davide; Mardari, Rodica; Ghiselli, Sara; Gerunda, Antonio; Ghirotto, Cristina; Fusetti, Stefano; Piacentile, Katherine; Scienza, Renato; Ermani, Mario; Martini, Alessandro

2016-03-01

Facial asymmetries in oculoauriculovertebral spectrum (OAVS) patients might require surgical corrections that are mostly based on qualitative approach and surgeon's experience. The present study aimed to develop a quantitative 3D CT imaging-based procedure suitable for maxillo-facial surgery planning in OAVS patients. Thirteen OAVS patients (mean age 3.5 ± 4.0 years; range 0.2-14.2, 6 females) and 13 controls (mean age 7.1 ± 5.3 years; range 0.6-15.7, 5 females) who underwent head CT examination were retrospectively enrolled. Eight bilateral anatomical facial landmarks were defined on 3D CT images (porion, orbitale, most anterior point of frontozygomatic suture, most superior point of temporozygomatic suture, most posterior-lateral point of the maxilla, gonion, condylion, mental foramen) and distance from orthogonal planes (in millimeters) was used to evaluate the asymmetry on each axis and to calculate a global asymmetry index of each anatomical landmark. Mean asymmetry values and relative confidence intervals were obtained from the control group. OAVS patients showed 2.5 ± 1.8 landmarks above the confidence interval while considering the global asymmetry values; 12 patients (92%) showed at least one pathologically asymmetric landmark. Considering each axis, the mean number of pathologically asymmetric landmarks increased to 5.5 ± 2.6 (p = 0.002) and all patients presented at least one significant landmark asymmetry. Modern CT-based 3D reconstructions allow accurate assessment of facial bone asymmetries in patients affected by OAVS. The evaluation as a global score and in different orthogonal axes provides precise quantitative data suitable for maxillo-facial surgical planning. CT-based 3D reconstruction might allow a quantitative approach for planning and following-up maxillo-facial surgery in OAVS patients.

What determines direction of asymmetry: genes, environment or chance?

PubMed Central

2016-01-01

Conspicuous asymmetries seen in many animals and plants offer diverse opportunities to test how the development of a similar morphological feature has evolved in wildly different types of organisms. One key question is: do common rules govern how direction of asymmetry is determined (symmetry is broken) during ontogeny to yield an asymmetrical individual? Examples from numerous organisms illustrate how diverse this process is. These examples also provide some surprising answers to related questions. Is direction of asymmetry in an individual determined by genes, environment or chance? Is direction of asymmetry determined locally (structure by structure) or globally (at the level of the whole body)? Does direction of asymmetry persist when an asymmetrical structure regenerates following autotomy? The answers vary greatly for asymmetries as diverse as gastropod coiling direction, flatfish eye side, crossbill finch bill crossing, asymmetrical claws in shrimp, lobsters and crabs, katydid sound-producing structures, earwig penises and various plant asymmetries. Several examples also reveal how stochastic asymmetry in mollusc and crustacean early cleavage, in Drosophila oogenesis, and in Caenorhabditis elegans epidermal blast cell movement, is a normal component of deterministic development. Collectively, these examples shed light on the role of genes as leaders or followers in evolution. This article is part of the themed issue ‘Provocative questions in left–right asymmetry’. PMID:27821528

Measurements of direct CP-violating asymmetries in charmless decays of bottom baryons.

PubMed

Aaltonen, T; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Auerbach, B; Aurisano, A; Azfar, F; Badgett, W; Bae, T; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Barria, P; Bartos, P; Bauce, M; Bedeschi, F; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Bhatti, A; Bland, K R; Blumenfeld, B; Bocci, A; Bodek, A; Bortoletto, D; Boudreau, J; Boveia, A; Brigliadori, L; Bromberg, C; Brucken, E; Budagov, J; Budd, H S; Burkett, K; Busetto, G; Bussey, P; Butti, P; Buzatu, A; Calamba, A; Camarda, S; Campanelli, M; Canelli, F; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Cho, K; Chokheli, D; Clark, A; Clarke, C; Convery, M E; Conway, J; Corbo, M; Cordelli, M; Cox, C A; Cox, D J; Cremonesi, M; Cruz, D; Cuevas, J; Culbertson, R; d'Ascenzo, N; Datta, M; de Barbaro, P; Demortier, L; Deninno, M; D'Errico, M; Devoto, F; Di Canto, A; Di Ruzza, B; Dittmann, J R; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Ebina, K; Edgar, R; Elagin, A; Erbacher, R; Errede, S; Esham, B; Farrington, S; Fernández Ramos, J P; Field, R; Flanagan, G; Forrest, R; Franklin, M; Freeman, J C; Frisch, H; Funakoshi, Y; Galloni, C; Garfinkel, A F; Garosi, P; Gerberich, H; Gerchtein, E; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Giokaris, N; Giromini, P; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldin, D; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González López, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gramellini, E; Grinstein, S; Grosso-Pilcher, C; Group, R C; Guimaraes da Costa, J; Hahn, S R; Han, J Y; Happacher, F; Hara, K; Hare, M; Harr, R F; Harrington-Taber, T; Hatakeyama, K; Hays, C; Heinrich, J; Herndon, M; Hocker, A; Hong, Z; Hopkins, W; Hou, S; Hughes, R E; Husemann, U; Hussein, M; Huston, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jang, D; Jayatilaka, B; Jeon, E J; Jindariani, S; Jones, M; Joo, K K; Jun, S Y; Junk, T R; Kambeitz, M; Kamon, T; Karchin, P E; Kasmi, A; Kato, Y; Ketchum, W; Keung, J; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S H; Kim, S B; Kim, Y J; Kim, Y K; Kimura, N; Kirby, M; Knoepfel, K; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kurata, M; Laasanen, A T; Lammel, S; Lancaster, M; Lannon, K; Latino, G; Lee, H S; Lee, J S; Leo, S; Leone, S; Lewis, J D; Limosani, A; Lipeles, E; Lister, A; Liu, H; Liu, Q; Liu, T; Lockwitz, S; Loginov, A; Lucchesi, D; Lucà, A; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lys, J; Lysak, R; Madrak, R; Maestro, P; Malik, S; Manca, G; Manousakis-Katsikakis, A; Marchese, L; Margaroli, F; Marino, P; Martínez, M; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McNulty, R; Mehta, A; Mehtala, P; Mesropian, C; Miao, T; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nakano, I; Napier, A; Nett, J; Neu, C; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Ortolan, L; Pagliarone, C; Palencia, E; Palni, P; Papadimitriou, V; Parker, W; Pauletta, G; Paulini, M; Paus, C; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pondrom, L; Poprocki, S; Potamianos, K; Pranko, A; Prokoshin, F; Ptohos, F; Punzi, G; Ranjan, N; Redondo Fernández, I; Renton, P; Rescigno, M; Rimondi, F; Ristori, L; Robson, A; Rodriguez, T; Rolli, S; Ronzani, M; Roser, R; Rosner, J L; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Sakumoto, W K; Sakurai, Y; Santi, L; Sato, K; Saveliev, V; Savoy-Navarro, A; Schlabach, P; Schmidt, E E; Schwarz, T; Scodellaro, L; Scuri, F; Seidel, S; Seiya, Y; Semenov, A; Sforza, F; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shochet, M; Shreyber-Tecker, I; Simonenko, A; Sliwa, K; Smith, J R; Snider, F D; Song, H; Sorin, V; St Denis, R; Stancari, M; Stentz, D; Strologas, J; Sudo, Y; Sukhanov, A; Suslov, I; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thomson, E; Thukral, V; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Ukegawa, F; Uozumi, S; Vázquez, F; Velev, G; Vellidis, C; Vernieri, C; Vidal, M; Vilar, R; Vizán, J; Vogel, M; Volpi, G; Wagner, P; Wallny, R; Wang, S M; Waters, D; Wester, W C; Whiteson, D; Wicklund, A B; Wilbur, S; Williams, H H; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, H; Wright, T; Wu, X; Wu, Z; Yamamoto, K; Yamato, D; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yeh, G P; Yi, K; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Zanetti, A M; Zeng, Y; Zhou, C; Zucchelli, S

2014-12-12

We report final measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using the complete √s=1.96  TeV proton-antiproton collisions data set, corresponding to 9.3  fb⁻¹ of integrated luminosity, we measure A(Λ(b)⁰→pπ⁻)=+0.06±0.07(stat)±0.03(syst) and A(Λ(b)⁰→pK⁻)=-0.10±0.08(stat)±0.04(syst), compatible with no asymmetry. In addition we measure the CP-violating asymmetries in B(s)⁰→K⁻π⁺ and B⁰→K⁺π⁻ decays to be A(B(s)⁰→K⁻π⁺)=+0.22±0.07(stat)±0.02(syst) and A(B⁰→K⁺π⁻)=-0.083±0.013(stat)±0.004(syst), respectively, which are significantly different from zero and consistent with current world averages.

A topographically forced asymmetry in the martian circulation and climate.

PubMed

Richardson, Mark I; Wilson, R John

2002-03-21

Large seasonal and hemispheric asymmetries in the martian climate system are generally ascribed to variations in solar heating associated with orbital eccentricity. As the orbital elements slowly change (over a period of >104 years), characteristics of the climate such as dustiness and the vigour of atmospheric circulation are thought to vary, as should asymmetries in the climate (for example, the deposition of water ice at the northern versus the southern pole). Such orbitally driven climate change might be responsible for the observed layering in Mars' polar deposits by modulating deposition of dust and water ice. Most current theories assume that climate asymmetries completely reverse as the angular distance between equinox and perihelion changes by 180 degrees. Here we describe a major climate mechanism that will not precess in this way. We show that Mars' global north-south elevation difference forces a dominant southern summer Hadley circulation that is independent of perihelion timing. The Hadley circulation, a tropical overturning cell responsible for trade winds, largely controls interhemispheric transport of water and the bulk dustiness of the atmosphere. The topography therefore imprints a strong handedness on climate, with water ice and the active formation of polar layered deposits more likely in the north.

Sum Rules of Charm CP Asymmetries beyond the SU(3)_{F} Limit.

PubMed

Müller, Sarah; Nierste, Ulrich; Schacht, Stefan

2015-12-18

We find new sum rules between direct CP asymmetries in D meson decays with coefficients that can be determined from a global fit to branching ratio data. Our sum rules eliminate the penguin topologies P and PA, which cannot be determined from branching ratios. In this way, we can make predictions about direct CP asymmetries in the standard model without ad hoc assumptions on the sizes of penguin diagrams. We consistently include first-order SU(3)_{F} breaking in the topological amplitudes extracted from the branching ratios. By confronting our sum rules with future precise data from LHCb and Belle II, one will identify or constrain new-physics contributions to P or PA. The first sum rule correlates the CP asymmetries a_{CP}^{dir} in D^{0}→K^{+}K^{-}, D^{0}→π^{+}π^{-}, and D^{0}→π^{0}π^{0}. We study the region of the a_{CP}^{dir}(D^{0}→π^{+}π^{-})-a_{CP}^{dir}(D^{0}→π^{0}π^{0}) plane allowed by current data and find that our sum rule excludes more than half of the allowed region at 95% C.L. Our second sum rule correlates the direct CP asymmetries in D^{+}→K[over ¯]^{0}K^{+}, D_{s}^{+}→K^{0}π^{+}, and D_{s}^{+}→K^{+}π^{0}.

Fertility affects asymmetry detection not symmetry preference in assessments of 3D facial attractiveness.

PubMed

Lewis, Michael B

2017-09-01

Consistent with theories from evolutionary psychology, facial symmetry correlates with attractiveness. Further, the preference for symmetrical faces appears to be affected by fertility in women. One limitation of previous research is that faces are often symmetrically lit front-views and so symmetry can be assessed using 2D pictorial information. Another limitation is that two-alternative-forced-choice (2afc) tasks are often used to assess symmetry preference and these cannot distinguish between differences in preference for symmetry and differences in ability of asymmetry detection. The current study used three tasks to assess the effects of facial symmetry: attractiveness ratings, 2afc preference and asymmetry detection. To break the link between 2D pictorial symmetry and facial symmetry, 3D computer generated heads were used with asymmetrical lighting and yaw rotation. Facial symmetry correlated with attractiveness even under more naturalistic viewing conditions. Path analysis indicates that the link between fertility and 2afc symmetry preference is mediated by asymmetry detection not increased preference for symmetry. The existing literature on symmetry preference and attractiveness is reinterpreted in terms of differences in asymmetry detection. Copyright © 2017 Elsevier B.V. All rights reserved.

Acoustic and Perceptual Effects of Left–Right Laryngeal Asymmetries Based on Computational Modeling

PubMed Central

Samlan, Robin A.; Story, Brad H.; Lotto, Andrew J.; Bunton, Kate

2015-01-01

Purpose Computational modeling was used to examine the consequences of 5 different laryngeal asymmetries on acoustic and perceptual measures of vocal function. Method A kinematic vocal fold model was used to impose 5 laryngeal asymmetries: adduction, edge bulging, nodal point ratio, amplitude of vibration, and starting phase. Thirty /a/ and /I/ vowels were generated for each asymmetry and analyzed acoustically using cepstral peak prominence (CPP), harmonics-to-noise ratio (HNR), and 3 measures of spectral slope (H1*-H2*, B0-B1, and B0-B2). Twenty listeners rated voice quality for a subset of the productions. Results Increasingly asymmetric adduction, bulging, and nodal point ratio explained significant variance in perceptual rating (R2 = .05, p < .001). The same factors resulted in generally decreasing CPP, HNR, and B0-B2 and in increasing B0-B1. Of the acoustic measures, only CPP explained significant variance in perceived quality (R2 = .14, p < .001). Increasingly asymmetric amplitude of vibration or starting phase minimally altered vocal function or voice quality. Conclusion Asymmetries of adduction, bulging, and nodal point ratio drove acoustic measures and perception in the current study, whereas asymmetric amplitude of vibration and starting phase demonstrated minimal influence on the acoustic signal or voice quality. PMID:24845730

Currents in the DIII-D Tokamak

NASA Astrophysics Data System (ADS)

Azari, A.; Eidietis, N. W.

2012-10-01

Loss of vertical control of an elongated tokamak plasma results in a vertical displacement event (VDE) which can induce large currents on open field lines and exert high JxB forces on in-vessel components. An array of first-wall tile current monitors on DIII-D provides direct measurement of the poloidal halo currents. These measurements are analyzed to create a database of halo current magnitude and asymmetry, which are found to lie within the ranges seen by numerous other tokamaks in the ITPA Disruption Database. In addition, an analysis of halo asymmetry rotation is presented, as rotation at the resonance frequencies of in-vessel components could lead to significant amplification of the halo forces. Halo current rotation is found to be far more prevalent in old (1997-2002) DIII-D halo current data than recent data (2009), perhaps due to a change in divertor geometry over that time.

Discriminating different Z{sup '}'s via asymmetries at the LHC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou Zhongqiu; Xiao Bo; Wang Youkai

2011-05-01

In practice the asymmetry, which is defined based on the angular distribution of the final states in scattering or decay processes, can be utilized to scrutinize underlying dynamics in and/or beyond the standard model (BSM). As one of the possible BSM physics which might be discovered early at the LHC, extra neutral gauge bosons Z{sup '}'s are theoretically well motivated. Once Z{sup '}'s are discovered at the LHC, it is crucial to discriminate different Z{sup '}'s in various BSM. In principle such a task can be accomplished by measuring the angular distribution of the final states which are produced viamore » Z{sup '}-mediated processes. In the real data analysis, asymmetry is always adopted. In the literature several asymmetries have been proposed at the LHC. Based on these works, we stepped further on to study how to optimize the asymmetries in the left-right model and the sequential standard model, as the examples of BSM. In this paper, we examined four kinds of asymmetries, namely, rapidity-dependent forward-backward asymmetry, oneside forward-backward asymmetry, central charge asymmetry, and edge charge asymmetry (see text for details), with l{sup +}l{sup -} (l=e, {mu}), bb, and tt as the final states. In the calculations with bb and tt final states, the QCD-induced higher-order contributions to the asymmetric cross section were also included. For each kind of final state, we estimated the four kinds of asymmetries and especially the optimal cut usually associated with the definition of the asymmetry. Our numerical results indicated that the capacity to discriminate Z{sup '} models can be improved by imposing the optimal cuts.« less

Forward-backward asymmetry in top quark-antiquark production

DOE PAGES

Abazov, Victor Mukhamedovich

2011-12-12

We present a measurement of forward-backward asymmetry in top quark-antiquark production in proton-antiproton collisions in the final state containing a lepton and at least four jets. Using a dataset corresponding to an integrated luminosity of 5.4 fb -1, collected by the D0 experiment at the Fermilab Tevatron Collider, we measure the t{bar t} forward-backward asymmetry to be (9.2 ± 3.7)% at the reconstruction level. When corrected for detector acceptance and resolution, the asymmetry is found to be (19.6 ± 6.5)%. We also measure a corrected asymmetry based on the lepton from a top quark decay, found to be (15.2 ±more » 4.0)%. The results are compared to predictions based on the next-to-leading-order QCD generator mc@nlo. The sensitivity of the measured and predicted asymmetries to the modeling of gluon radiation is discussed.« less

Infant Positioning, Baby Gear Use, and Cranial Asymmetry.

PubMed

Zachry, Anne H; Nolan, Vikki G; Hand, Sarah B; Klemm, Susan A

2017-12-01

Objectives This study aimed to identify predictors of cranial asymmetry. We hypothesize that among infants diagnosed with cranial asymmetry in the sampled region, there is an association between exposure to more time in baby gear and less awake time in prone and side-lying than in infants who do not present with this condition. Methods The study employed a cross sectional survey of caregivers of typically developing infants and infants diagnosed with cranial asymmetry. Results A mutivariable model reveals that caregivers of children who are diagnosed with cranial asymmetry report their children spending significantly less time in prone play than those children without a diagnosis of cranial asymmetry. Side-lying and time spent in baby gear did not attain statistical significance. Conclusions for Practice Occupational therapists, physical therapists, pediatricians, nurses and other health care professionals must provide parents with early education about the importance of varying positions and prone play in infancy and address fears and concerns that may serve as barriers to providing prone playtime.

Bottom-quark forward-backward asymmetry in the standard model and beyond.

PubMed

Grinstein, Benjamín; Murphy, Christopher W

2013-08-09

We computed the bottom-quark forward-backward asymmetry at the Tevatron in the standard model (SM) and for several new physics scenarios. Near the Z pole, the SM bottom asymmetry is dominated by tree level exchanges of electroweak gauge bosons. While above the Z pole, next-to-leading order QCD dominates the SM asymmetry as was the case with the top-quark forward-backward asymmetry. Light new physics, M(NP)≲150  GeV, can cause significant deviations from the SM prediction for the bottom asymmetry. The bottom asymmetry can be used to distinguish between competing new physics (NP) explanations of the top asymmetry based on how the NP interferes with s-channel gluon and Z exchange.

Birth order and fluctuating asymmetry: a first look.

PubMed Central

Lalumière, M L; Harris, G T; Rice, M E

1999-01-01

We investigated the hypothesis that maternal immunoreactivity to male-specific features of the foetus can increase developmental instability. We predicted that the participants' number of older brothers would be positively related to the fluctuating asymmetry of ten bilateral morphological traits. The participants were 40 adult male psychiatric patients and 31 adult male hospital employees. Consistent with the hypothesis, the participants' number of older brothers--but not number of older sisters, younger brothers or younger sisters--was positively associated with fluctuating asymmetry. The patients had significantly larger fluctuating asymmetry scores and tended to have more older brothers than the employees, but the positive relationship between the number of older brothers and fluctuating asymmetry was observed in both groups. PMID:10643079

Cerebral blood flow asymmetries in headache-free migraineurs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levine, S.R.; Welch, K.M.; Ewing, J.R.

1987-11-01

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

Spot-welding solid targets for high current cyclotron irradiation

PubMed Central

Ellison, Paul A.; Valdovinos, Hector F.; Graves, Stephen A.; Barnhart, Todd E.; Nickles, Robert J.

2016-01-01

Zirconium-89 finds broad application for use in positron emission tomography. Its cyclotron production has been limited by the heat transfer from yttrium targets at high beam currents. A spot welding technique allows a three-fold increase in beam current, without affecting 89Zr quality. An yttrium foil, welded to a jet-cooled tantalum support base accommodates a 50 μA proton beam degraded to 14 MeV. The resulting activity yield of 48 ± 4 MBq/(μA·hr) now extends the outreach of 89Zr for a broader distribution. PMID:27771445

The association between static pelvic asymmetry and low back pain.

PubMed

Levangie, P K

1999-06-15

A cross-sectional case-control approach was used to estimate the association between low back pain of less than 12 months' duration and pelvic asymmetry among 21-50-year-old patients seeking physical therapy services. To evaluate the premise that asymmetrical positioning of the innominates of the pelvis is a source of low back pain. No published studies have been conducted to evaluate systematically the association between low back pain and pelvic asymmetry in a clinic-based sample. Pelvic landmark data were obtained in 144 cases and 138 control subjects. The associations of low back pain with levels of pelvic asymmetry were estimated by use of odds ratios and 95% confidence intervals. Effect modification and confounding of the low back pain-pelvic asymmetry association by several factors was assessed and alternative asymmetry measures considered. Pelvic asymmetry was not positively associated with low back pain in any way that seemed clinically meaningful. Asymmetry of posterior superior iliac spine landmarks showed some evidence of a weak positive association with low back pain. In the absence of meaningful positive association between pelvic asymmetry and low back pain, evaluation and treatment strategies based on this premise should be questioned.

Production asymmetry of $$\\Lambda^0$$ and $${\\overline{\\Lambda}}^0$$ in $$\\pi^{\\pm}$$, $$K^{\\pm}$$, p - nucleon collisions at 250 GeV/c (in Portuguese)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nicola, Marcello Santo

Using data from Fermilab xed-target experiment E769, we have measured particleantiparticle production asymmetries for Λ 0 hyperons in π ± - nucleon interactions, K ± - nucleon interactions and p - nucleon interactions at 250 GeV/c. The asymmetries are measured as functions of Feynman-x (x f ) and p T 2 over the ranges 0 ≤ p T 2 ≤ 4(GeV/c) 2 and -0.12 ≤ x F ≤ 0.12 (for positive beam) and 0 ≤ p T 2 ≤ 10(GeV/c) 2 and -0.16 ≤ x F ≤ 0:.0 for the negative beam. We find substantial asymmetries, even at x Fmore » = 0. We also observe leading-particle-type asymmetries which qualitatively agree with theoretical predictions.« less

Symmetry and asymmetry in the human brain

NASA Astrophysics Data System (ADS)

Hugdahl, Kenneth

2005-10-01

Structural and functional asymmetry in the human brain and nervous system is reviewed in a historical perspective, focusing on the pioneering work of Broca, Wernicke, Sperry, and Geschwind. Structural and functional asymmetry is exemplified from work done in our laboratory on auditory laterality using an empirical procedure called dichotic listening. This also involves different ways of validating the dichotic listening procedure against both invasive and non-invasive techniques, including PET and fMRI blood flow recordings. A major argument is that the human brain shows a substantial interaction between structurally, or "bottom-up" asymmetry and cognitively, or "top-down" modulation, through a focus of attention to the right or left side in auditory space. These results open up a more dynamic and interactive view of functional brain asymmetry than the traditional static view that the brain is lateralized, or asymmetric, only for specific stimuli and stimulus properties.

The Relationship Between Asymmetry and Athletic Performance: A Critical Review.

PubMed

Maloney, Sean J

2018-05-08

Maloney, SJ. The relationship between asymmetry and athletic performance: A critical review. J Strength Cond Res XX(X): 000-000, 2018-Symmetry may be defined as the quality to demonstrate an exact correspondence of size, shape, and form when split along a given axis. Although it has been widely asserted that the bilateral asymmetries are detrimental to athletic performance, research does not wholly support such an association. Moreover, the research rarely seeks to distinguish between different types of bilateral asymmetry. Fluctuating asymmetries describe bilateral differences in anthropometric attributes, such as nostril width and ear size, and are thought to represent the developmental stability of an organism. There is evidence to suggest that fluctuating asymmetries may be related to impaired athletic performance, although contradictory findings have been reported. Sporting asymmetries is a term that may better describe bilateral differences in parameters, such as force output or jump height. These asymmetries are likely to be a function of limb dominance and magnified by long-standing participation within sport. Sporting asymmetries do not seem to carry a clear influence on athletic performance measures. Given the vast discrepancy in the methodologies used by different investigations, further research is warranted. Recent investigations have demonstrated that training interventions can reduce sporting asymmetries and improve performance. However, studies have not sought to determine whether the influence of sporting asymmetry is independent of improvements in neuromuscular parameters. It may be hypothesized that the deficient (weaker) limb has a greater potential for adaptation in comparison to the strong limb and may demonstrate greater responsiveness to training.

Geometric asymmetry driven Janus micromotors.

PubMed

Zhao, Guanjia; Pumera, Martin

2014-10-07

The production and application of nano-/micromotors is of great importance. In order for the motors to work, asymmetry in their chemical composition or physical geometry must be present if no external asymmetric field is applied. In this paper, we present a "coconut" micromotor made of platinum through the partial or complete etching of the silica templates. It was shown that although both the inner and outer surfaces are made of the same material (Pt), motion of the structure can be observed as the convex surface is capable of generating oxygen bubbles. This finding shows that not only the chemical asymmetry of the micromotor, but also its geometric asymmetry can lead to fast propulsion of the motor. Moreover, a considerably higher velocity can be seen for partially etched coconut structures than the velocities of Janus or fully etched, shell-like motors. These findings will have great importance on the design of future micromotors.

Asymmetry dependence of the caloric curve for mononuclei

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoel, C.; Sobotka, L. G.; Charity, R. J.

2007-01-15

The asymmetry dependence of the caloric curve, for mononuclear configurations, is studied as a function of neutron-to-proton asymmetry with a model that allows for independent variation of the neutron and proton surface diffusenesses. The evolution of the effective mass with density and excitation is included in a schematic fashion and the entropies are extracted in a local density approximation. The plateau in the caloric curve displays only a slight sensitivity to the asymmetry.

Analysis of Current-mode Detectors For Resonance Detection In Neutron Optics Time Reversal Symmetry Experiment

NASA Astrophysics Data System (ADS)

Forbes, Grant; Noptrex Collaboration

2017-09-01

One of the most promising explanations for the observed matter-antimatter asymmetry in our universe is the search for new sources of time-reversal (T) symmetry violation. The current amount of violation seen in the kaon and B-meson systems is not sufficient to describe this asymmetry. The Neutron Optics Time Reversal Experiment Collaboration (NOPTREX) is a null test for T violation in polarized neutron transmission through a polarized 139La target. Due to the high neutron flux needed for this experiment, as well as the ability to effectively subtract background noise, a current-mode neutron detector that can resolve resonances at epithermal energies has been proposed. In order to ascertain if this detector design would meet the requirements for the eventual NOPTREX experiment, prototypical detectors were tested at the NOBORU beam at the Japan Proton Accelerator Research Complex (JPARC) facility. Resonances in In and Ta were measured and the collected data was analyzed. This presentation will describe the analysis process and the efficacy of the detectors will be discussed. Department of Energy under Contract DE-SC0008107, UGRAS Scholarship.

Measurement of the Parity-Violating directional Gamma-ray Asymmetry in Polarized Neutron Capture on ^35Cl

NASA Astrophysics Data System (ADS)

Fomin, Nadia

2012-03-01

The NPDGamma experiment aims to measure the parity-odd correlation between the neutron spin and the direction of the emitted photon in neutron-proton capture. A parity violating asymmetry (to be measured to 10-8) from this process can be directly related to the strength of the hadronic weak interaction between nucleons. As part of the commissioning runs on the Fundamental Neutron Physics beamline at the Spallation Neutron Source at ORNL, the gamma-ray asymmetry from the parity-violating capture of cold neutrons on ^35Cl was measured, primarily to check for systematic effects and false asymmtries. The current precision from existing world measurements on this asymmetry is at the level of 10-6 and we believe we can improve it. The analysis methodology as well as preliminary results will be presented.

Beyond apoptosis: the mechanism and function of phosphatidylserine asymmetry in the membrane of activating mast cells.

PubMed

Rysavy, Noel M; Shimoda, Lori M N; Dixon, Alyssa M; Speck, Mark; Stokes, Alexander J; Turner, Helen; Umemoto, Eric Y

2014-01-01

Loss of plasma membrane asymmetry is a hallmark of apoptosis, but lipid bilayer asymmetry and loss of asymmetry can contribute to numerous cellular functions and responses that are independent of programmed cell death. Exofacial exposure of phosphatidylserine occurs in lymphocytes and mast cells after antigenic stimulation and in the absence of apoptosis, suggesting that there is a functional requirement for phosphatidylserine exposure in immunocytes. In this review we examine current ideas as to the nature of this functional role in mast cell activation. Mechanistically, there is controversy as to the candidate proteins responsible for phosphatidylserine translocation from the internal to external leaflet, and here we review the candidacies of mast cell PLSCR1 and TMEM16F. Finally we examine the potential relationship between functionally important mast cell membrane perturbations and phosphatidylserine exposure during activation.

Asymmetry in convection and restratification in the Nordic Seas: an idealized model study

NASA Astrophysics Data System (ADS)

Ypma, Stefanie L.; Brüggemann, Nils; Pietrzak, Julie D.; Katsman, Caroline A.

2017-04-01

The Nordic Seas are an important production region for dense water masses that feed the lower limb of the Atlantic Meridional Overturning Circulation. They display a pronounced hydrographic asymmetry, with a warm eastern basin, and a cold western basin. Previous studies have shown that this asymmetry is set by the interplay between large eddies shed near the coast of Norway where the continental slope steepens, and the Mohn-Knipovich ridge that separates the Lofoten Basin in the east from the Greenland Basin in the west. While it is known from earlier studies that eddies play a crucial role for the yearly cycle of wintertime convection and summertime restratification in marginal seas like the Labrador Sea, the situation in the Nordic Seas is different as the large eddies can only restratify the eastern part of the Nordic Seas due to the presence of the ridge. Possibly due to this asymmetry in eddy activity and a weaker stratification as a result, the western basin is more sensitive for intense deep convection. The question remains how this area is restratified after a deep convection event in the absence of large eddies and how the dense water is able to leave the basin. An high resolution, idealized model configuration of the MITgcm is used that reproduces the main characteristics of the Nordic Seas, including a warm cyclonic boundary current, a strong eddy field in the east and the hydrographic asymmetry between east and west. The idealized approach enables multiple sensitivity studies to changes in the eddy field and the boundary current and provides the possibility to investigate cause and effect, while keeping the set-up simple. We will present results of tracer studies where the sensitivity of the spreading and the restratification of dense water to the formation location in both basins is studied.

CP asymmetry in charged Higgs decays to chargino-neutralino pairs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frank, Mariana; Turan, Ismail

2007-10-01

We analyze the charge-parity (CP) asymmetry in the charged Higgs boson decays to chargino-neutralino pairs, H{sup {+-}}{yields}{chi}{sub i}{sup {+-}}{chi}{sub j}{sup 0}, i=1, 2, j=1,...,4. We show first that these modes have a large branching ratio for m{sub H{sup {+-}}} > or approx. 600 GeV. We use Cutkosky rules to obtain the analytical formulas needed for the evaluation of the asymmetry under consideration. We then calculate the CP asymmetry in chargino-neutralino decays by including supersymmetric mass bounds, as well as constraints from b{yields}s{gamma} (g-2){sub {mu}}, {delta}{rho} and electric dipole moments. Finally, we discuss observability of the asymmetry at the LHC bymore » calculating the number of required charged Higgs events to observe the asymmetry for each decay channel. We show that the inclusion of constraints considerably reduces the projected CP asymmetry, and that the optimal channel for observing the asymmetry is H{sup {+-}}{yields}{chi}{sub 1}{sup {+-}}{chi}{sub 2}{sup 0}.« less

Subcycle dynamics of Coulomb asymmetry in strong elliptical laser fields.

PubMed

Li, Min; Liu, Yunquan; Liu, Hong; Ning, Qicheng; Fu, Libin; Liu, Jie; Deng, Yongkai; Wu, Chengyin; Peng, Liang-You; Peng, Liangyou; Gong, Qihuang

2013-07-12

We measure photoelectron angular distributions of noble gases in intense elliptically polarized laser fields, which indicate strong structure-dependent Coulomb asymmetry. Using a dedicated semiclassical model, we have disentangled the contribution of direct ionization and multiple forward scattering on Coulomb asymmetry in elliptical laser fields. Our theory quantifies the roles of the ionic potential and initial transverse momentum on Coulomb asymmetry, proving that the small lobes of asymmetry are induced by direct ionization and the strong asymmetry is induced by multiple forward scattering in the ionic potential. Both processes are distorted by the Coulomb force acting on the electrons after tunneling. Lowering the ionization potential, the relative contribution of direct ionization on Coulomb asymmetry substantially decreases and Coulomb focusing on multiple rescattering is more important. We do not observe evident initial longitudinal momentum spread at the tunnel exit according to our simulation.

Femoral head asymmetry and coxa magna: anatomic study.

PubMed

Young, Ernest Y; Gebhart, Jeremy J; Bajwa, Navkirat; Cooperman, Daniel R; Ahn, Nicholas U

2014-06-01

Coxa magna, the asymmetrical circumferential enlargement of the femoral head, is an important sequela of pediatric disorders such as Legg-Calvé-Perthes disease. Definitions vary because of lack of controls and a scarcity of research on the distribution of the femoral head asymmetry. This study aims at defining the normal distribution of asymmetry between the left and the right femoral head and neck in the population and how demographics affect these properties. The study also looked at the distribution of side dominance (left or right). This study measured 230 paired femurs from individuals (20 to 40 y old) distributed for sex and ethnicity. The height and weight of the individuals were also recorded. The femoral head diameter and minimal femoral neck diameter in the anteroposterior view were measured on each paired femurs. The absolute and percent differences were determined to define asymmetry. Most of the population fell within 3% of asymmetry for the femoral head and 4% for the femoral neck. The maximum head percent asymmetry was 7.4%. Absolute difference in millimeters to percent asymmetry showed a ratio of 2:1 for the femoral head and 3:1 for the femoral neck. African Americans showed greater femoral head symmetry and a bias toward left-sided femoral head and neck enlargement when compared with their white counterparts. There was a high degree of symmetry between the left and right femoral heads and necks, which supports definitions found in the literature that define coxa magna above 10%. This study defines asymmetry in the femoral head in the normal population, which will help to define a quantitative definition of coxa magna.

Micropatterned mammalian cells exhibit phenotype-specific left-right asymmetry.

PubMed

Wan, Leo Q; Ronaldson, Kacey; Park, Miri; Taylor, Grace; Zhang, Yue; Gimble, Jeffrey M; Vunjak-Novakovic, Gordana

2011-07-26

Left-right (LR) asymmetry (handedness, chirality) is a well-conserved biological property of critical importance to normal development. Changes in orientation of the LR axis due to genetic or environmental factors can lead to malformations and disease. While the LR asymmetry of organs and whole organisms has been extensively studied, little is known about the LR asymmetry at cellular and multicellular levels. Here we show that the cultivation of cell populations on micropatterns with defined boundaries reveals intrinsic cell chirality that can be readily determined by image analysis of cell alignment and directional motion. By patterning 11 different types of cells on ring-shaped micropatterns of various sizes, we found that each cell type exhibited definite LR asymmetry (p value down to 10(-185)) that was different between normal and cancer cells of the same type, and not dependent on surface chemistry, protein coating, or the orientation of the gravitational field. Interestingly, drugs interfering with actin but not microtubule function reversed the LR asymmetry in some cell types. Our results show that micropatterned cell populations exhibit phenotype-specific LR asymmetry that is dependent on the functionality of the actin cytoskeleton. We propose that micropatterning could potentially be used as an effective in vitro tool to study the initiation of LR asymmetry in cell populations, to diagnose disease, and to study factors involved with birth defects in laterality.

Spot-welding solid targets for high current cyclotron irradiation.

PubMed

Ellison, Paul A; Valdovinos, Hector F; Graves, Stephen A; Barnhart, Todd E; Nickles, Robert J

2016-12-01

Zirconium-89 finds broad application for use in positron emission tomography. Its cyclotron production has been limited by the heat transfer from yttrium targets at high beam currents. A spot welding technique allows a three-fold increase in beam current, without affecting 89 Zr quality. An yttrium foil, welded to a jet-cooled tantalum support base accommodates a 50µA proton beam degraded to 14MeV. The resulting activity yield of 48±4 MBq/(μA∙hr) now extends the outreach of 89 Zr for a broader distribution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mapping the stability of human brain asymmetry across five sex-chromosome aneuploidies.

PubMed

Lin, Amy; Clasen, Liv; Lee, Nancy Raitano; Wallace, Gregory L; Lalonde, Francois; Blumenthal, Jonathan; Giedd, Jay N; Raznahan, Armin

2015-01-07

The human brain displays stereotyped and early emerging patterns of cortical asymmetry in health. It is unclear if these asymmetries are highly sensitive to genetic and environmental variation or fundamental features of the brain that can survive severe developmental perturbations. To address this question, we mapped cortical thickness (CT) asymmetry in a group of genetically defined disorders known to impact CT development. Participants included 137 youth with one of five sex-chromosome aneuploidies [SCAs; XXX (n = 28), XXY (n = 58), XYY (n = 26), XXYY (n = 20), and XXXXY (n = 5)], and 169 age-matched typically developing controls (80 female). In controls, we replicated previously reported rightward inferior frontal and leftward lateral parietal CT asymmetry. These opposing frontoparietal CT asymmetries were broadly preserved in all five SCA groups. However, we also detected foci of shifting CT asymmetry with aneuploidy, which fell almost exclusively within regions of significant CT asymmetry in controls. Specifically, X-chromosome aneuploidy accentuated normative rightward inferior frontal asymmetries, while Y-chromosome aneuploidy reversed normative rightward medial prefrontal and lateral temporal asymmetries. These findings indicate that (1) the stereotyped normative pattern of opposing frontoparietal CT asymmetry arises from developmental mechanisms that can withstand gross chromosomal aneuploidy and (2) X and Y chromosomes can exert focal, nonoverlapping and directionally opposed influences on CT asymmetry within cortical regions of significant asymmetry in health. Our study attests to the resilience of developmental mechanisms that support the global patterning of CT asymmetry in humans, and motivates future research into the molecular bases and functional consequences of sex chromosome dosage effects on CT asymmetry. Copyright © 2015 the authors 0270-6474/15/350140-06$15.00/0.

Extraction of the neutron electric form factor from measurements of inclusive double spin asymmetries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sulkosky, V.; Jin, G.; Long, E.

Background: Measurements of the neutron charge form factor, Gmore » $$n\\atop{E}$$, are challenging because the neutron has no net charge. Additionally, measurements of the neutron form factors must use nuclear targets which require accurately accounting for nuclear effects. Extracting G$$n\\atop{E}$$ with different targets and techniques provides an important test of our handling of these effects. Purpose: The goal of the measurement was to use an inclusive asymmetry measurement technique to extract the neutron charge form factor at a four-momentum transfer of 1 (GeV/c) 2. This technique has very different systematic uncertainties than traditional exclusive measurements and thus serves as an independent check of whether nuclear effects have been taken into account correctly. Method: The inclusive quasielastic reaction 3$$→\\atop{He}$$ ($$→\\atop{e}$$, e') was measured at Jefferson Laboratory. The neutron electric form factor, G$$n\\atop{E}$$, was extracted at Q 2 = 0.98 ( GeV/c) 2 from ratios of electron-polarization asymmetries measured for two orthogonal target spin orientations. This Q 2 is high enough that the sensitivity to G$$n\\atop{E}$$ is not overwhelmed by the neutron magnetic contribution, and yet low enough that explicit neutron detection is not required to suppress pion production. Results: The neutron electric form factor, G$$n\\atop{E}$$, was determined to be 0.0414 ± 0.0077 ( stat ) ± 0.0022 ( syst ), providing the first high-precision inclusive extraction of the neutron's charge form factor. In conclusion: The use of the inclusive quasielastic 3$$→\\atop{He}$$ ($$→\\atop{e}$$, e') with a four-momentum transfer near 1 (GeV/c) 2 has been used to provide a unique measurement of G$$n\\atop{E}$$. This new result provides a systematically independent validation of the exclusive extraction technique results and implies that the nuclear corrections are understood. This is contrary to the proton form factor where asymmetry and differential

Extraction of the neutron electric form factor from measurements of inclusive double spin asymmetries

DOE PAGES

Sulkosky, V.; Jin, G.; Long, E.; ...

2017-12-26

Background: Measurements of the neutron charge form factor, Gmore » $$n\\atop{E}$$, are challenging because the neutron has no net charge. Additionally, measurements of the neutron form factors must use nuclear targets which require accurately accounting for nuclear effects. Extracting G$$n\\atop{E}$$ with different targets and techniques provides an important test of our handling of these effects. Purpose: The goal of the measurement was to use an inclusive asymmetry measurement technique to extract the neutron charge form factor at a four-momentum transfer of 1 (GeV/c) 2. This technique has very different systematic uncertainties than traditional exclusive measurements and thus serves as an independent check of whether nuclear effects have been taken into account correctly. Method: The inclusive quasielastic reaction 3$$→\\atop{He}$$ ($$→\\atop{e}$$, e') was measured at Jefferson Laboratory. The neutron electric form factor, G$$n\\atop{E}$$, was extracted at Q 2 = 0.98 ( GeV/c) 2 from ratios of electron-polarization asymmetries measured for two orthogonal target spin orientations. This Q 2 is high enough that the sensitivity to G$$n\\atop{E}$$ is not overwhelmed by the neutron magnetic contribution, and yet low enough that explicit neutron detection is not required to suppress pion production. Results: The neutron electric form factor, G$$n\\atop{E}$$, was determined to be 0.0414 ± 0.0077 ( stat ) ± 0.0022 ( syst ), providing the first high-precision inclusive extraction of the neutron's charge form factor. In conclusion: The use of the inclusive quasielastic 3$$→\\atop{He}$$ ($$→\\atop{e}$$, e') with a four-momentum transfer near 1 (GeV/c) 2 has been used to provide a unique measurement of G$$n\\atop{E}$$. This new result provides a systematically independent validation of the exclusive extraction technique results and implies that the nuclear corrections are understood. This is contrary to the proton form factor where asymmetry and differential

[Current Status of Targeted Treatment in Breast Cancer].

PubMed

Seiffert, Katharina; Schmalfeldt, Barbara; Müller, Volkmar

2017-11-01

Within the last years, significant improvements have been achieved in breast cancer treatment, particularly with the development of targeted therapies. Major progress has been made in identifying the drivers malignant growth in oestrogen-receptor-positive breast cancer and the mechanisms of resistance to endocrine therapy. This progress has translated into several targeted therapies that enhance the efficacy of endocrine therapy; inhibitors of the cyclin-dependent kinases CDK4 and CDK6 like palbociclib and inhibitors of mTOR substantially improve progression-free survival. For patients with HER2-positive disease the addition of Pertuzumab to Trastuzumab in combination with chemotherapy has been a significant improvement in anti-HER2 therapy in early as well as metastatic breast cancer. Evidence-based further line therapy options in the metastatic setting include T-DM1 and in later lines Lapatinib. For triple negative disease the angiogenesis inhibitor Bevacizumab is approved, which increases progression free survival. Immune checkpoint inhibitors, PARP-inhibitors or anti-androgens represent promising strategies, all of which are currently being evaluated in clinical trials. The development of predictive biomarkers to guide targeted therapies is still the subject of research. © Georg Thieme Verlag KG Stuttgart · New York.

Atypical Alpha Asymmetry in Adults with ADHD

ERIC Educational Resources Information Center

Hale, T. Sigi; Smalley, Susan L.; Hanada, Grant; Macion, James; McCracken, James T.; McGough, James J.; Loo, Sandra K.

2009-01-01

Introduction: A growing body of literature suggests atypical cerebral asymmetry and interhemispheric interaction in ADHD. A common means of assessing lateralized brain function in clinical populations has been to examine the relative proportion of EEG alpha activity (8-12 Hz) in each hemisphere (i.e., alpha asymmetry). Increased rightward alpha…

Measurements of Direct C P -Violating Asymmetries in Charmless Decays of Bottom Baryons

DOE PAGES

Aaltonen, T.; Amerio, S.; Amidei, D.; ...

2014-12-09

Here, we report final measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using the complete √s = 1.96 TeV proton-antiproton collisions data set, corresponding to 9.3 fb –1 of integrated luminosity, we measure A(Λ 0 b → pπ –) = +0.06 ± 0.07(stat) ± 0.03(syst) and A(Λ 0 b → pK –) = –0.10 ± 0.08(stat) ± 0.04(syst), compatible with no asymmetry. In addition we measure the CP-violating asymmetries in B 0 s → K –π + and B 0 → Kmore » +π – decays to be A(B 0 s → K –π +) = +0.22 ± 0.07(stat) ± 0.02(syst) and A(B 0 → K +π –)=–0.083 ± 0.013(stat) ± 0.004(syst), respectively, which are significantly different from zero and consistent with current world averages.« less

Common Genetic Variant in VIT Is Associated with Human Brain Asymmetry.

PubMed

Tadayon, Sayed H; Vaziri-Pashkam, Maryam; Kahali, Pegah; Ansari Dezfouli, Mitra; Abbassian, Abdolhossein

2016-01-01

Brain asymmetry varies across individuals. However, genetic factors contributing to this normal variation are largely unknown. Here we studied variation of cortical surface area asymmetry in a large sample of subjects. We performed principal component analysis (PCA) to capture correlated asymmetry variation across cortical regions. We found that caudal and rostral anterior cingulate together account for a substantial part of asymmetry variation among individuals. To find SNPs associated with this subset of brain asymmetry variation we performed a genome-wide association study followed by replication in an independent cohort. We identified one SNP (rs11691187) that had genome-wide significant association (P Combined = 2.40e-08). The rs11691187 is in the first intron of VIT. In a follow-up analysis, we found that VIT gene expression is associated with brain asymmetry in six donors of the Allen Human Brain Atlas. Based on these findings we suggest that VIT contributes to normal brain asymmetry variation. Our results can shed light on disorders associated with altered brain asymmetry.

Single and double spin asymmetries for pion electro-production from the deuteron in the resonance region

NASA Astrophysics Data System (ADS)

Careccia, Sharon L.

The single and double spin asymmetries At and Aet have been measured in pi- electro-production off the deuteron using a longitudinally polarized electron beam and a polarized ND3 target. The electron beam was polarized using a strained GaAs cathode and the target was polarized using Dynamic Nuclear Polarization. The data were collected at beam energies of 1.6, 1.7, 2.5 and 4.2 GeV in Hall B at Jefferson Lab in the spring of 2001. The final state particles were detected in the CEBAF Large Acceptance Spectrometer (CLAS). The d(e,e'pi-p)p exclusive channel was identified using the missing mass technique and the asymmetries were extracted as a function of the momentum transfer Q2, invariant mass W, and center of mass pion angles cos(theta*) and φ*. The results are generally in agreement with the phenomenological model MAID at low energies, but there are discrepancies in the 2nd and 3rd resonance regions, as well as at forward angles.

On the internal target model in a tracking task

NASA Technical Reports Server (NTRS)

Caglayan, A. K.; Baron, S.

1981-01-01

An optimal control model for predicting operator's dynamic responses and errors in target tracking ability is summarized. The model, which predicts asymmetry in the tracking data, is dependent on target maneuvers and trajectories. Gunners perception, decision making, control, and estimate of target positions and velocity related to crossover intervals are discussed. The model provides estimates for means, standard deviations, and variances for variables investigated and for operator estimates of future target positions and velocities.

Frontal EEG asymmetry as a moderator and mediator of emotion.

PubMed

Coan, James A; Allen, John J B

2004-10-01

Frontal EEG asymmetry appears to serve as (1) an individual difference variable related to emotional responding and emotional disorders, and (2) a state-dependent concomitant of emotional responding. Such findings, highlighted in this review, suggest that frontal EEG asymmetry may serve as both a moderator and a mediator of emotion- and motivation-related constructs. Unequivocal evidence supporting frontal EEG asymmetry as a moderator and/or mediator of emotion is lacking, as insufficient attention has been given to analyzing the frontal EEG asymmetries in terms of moderators and mediators. The present report reviews the frontal EEG asymmetry literature from the framework of moderators and mediators, and overviews data analytic strategies that would support claims of moderation and mediation.

A theoretical explanation for the Central Molecular Zone asymmetry

NASA Astrophysics Data System (ADS)

Sormani, Mattia C.; Treß, Robin G.; Ridley, Matthew; Glover, Simon C. O.; Klessen, Ralf S.; Binney, James; Magorrian, John; Smith, Rowan

2018-04-01

It has been known for more than 30 yr that the distribution of molecular gas in the innermost 300 parsecs of the Milky Way, the Central Molecular Zone, is strongly asymmetric. Indeed, approximately three quarters of molecular emission come from positive longitudes, and only one quarter from negative longitudes. However, despite much theoretical effort, the origin of this asymmetry has remained a mystery. Here, we show that the asymmetry can be neatly explained by unsteady flow of gas in a barred potential. We use high-resolution 3D hydrodynamical simulations coupled to a state-of-the-art chemical network. Despite the initial conditions and the bar potential being point symmetric with respect to the Galactic Centre, asymmetries develop spontaneously due to the combination of a hydrodynamical instability known as the `wiggle instability' and the thermal instability. The observed asymmetry must be transient: observations made tens of megayears in the past or in the future would often show an asymmetry in the opposite sense. Fluctuations of amplitude comparable to the observed asymmetry occur for a large fraction of time in our simulations, and suggest that the present is not an exceptional moment in the life of our Galaxy.

Current advances in targeted therapies for metastatic gastric cancer: improving patient care.

PubMed

Aguiar, Pedro Nazareth; Muniz, Thiago Pimentel; Miranda, Raelson Rodrigues; Tadokoro, Hakaru; Forones, Nora Manoukian; Monteiro, Ines-de-Paula; Castelo-Branco, Pedro; Janjigian, Yelena Y; De Mello, Ramon Andrade

2016-03-01

In this article, we review the literature on the current advances in targeted therapies for metastatic gastric cancer aimed at improving patient care. We conclude that the key to guiding targeted therapy is individual biomarkers, which are not completely elucidated. HER2 overexpression is the only predictive biomarker currently in use. Furthermore, it is necessary to understand that gastric tumors are heterogeneous; therefore, is impossible to evaluate a novel biological compound without evaluating personal biomarkers. The selection of patients who are able to receive each treatment is paramount for improving advanced gastric cancer survival and reducing unnecessary costs.

Vertebrate whole-body-action asymmetries and the evolution of right handedness: a comparison between humans and marine mammals.

PubMed

MacNeilage, Peter F

2013-09-01

As part of a vertebrate-wide trend toward left brain/right side asymmetries in routine whole-body actions, marine mammals show signs of rightward appendage-use biases, and short- and long-term turning asymmetries most of which are unique in non-humans in being just as strong as right handedness, and even stronger than human handedness-related turning biases. Short-term marine mammal turning asymmetries and human about-turning asymmetries share a leading right side, suggesting a commonality in left hemisphere intentional control. The long-term leftward turning bias that both groups share may be an indirect result of both sensory and motor influences on the right side in dolphins, but be induced by a right-hemisphere-controlled spatial/attentional bias to the left in humans. Marine mammals may share, with humans and other higher primates, a left hemisphere specialization for action dynamics, although evidence is currently lacking for human-like right hemisphere specializations relevant to action in other vertebrates. Copyright © 2013 Wiley Periodicals, Inc.

Survey of A{sub LT'} asymmetries in semi-exclusive electron scattering on He4 and C12

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dan Protopopescu; et. Al.

2005-02-21

Single spin azimuthal asymmetries A{sub LT'} were measured at Jefferson Lab using 2.2 and 4.4 GeV longitudinally polarized electrons incident on {sup 4}He and {sup 12}C targets in the CLAS detector. A{sub LT'} is related to the imaginary part of the longitudinal-transverse interference and in quasifree nucleon knockout it provides an unambiguous signature for final state interactions (FSI). Experimental values of A{sub LT'} were found to be below 5%, typically |A{sub LT'}| < 3% for data with good statistical precision. Optical Model in Eikonal Approximation (OMEA) and Relativistic Multiple-Scattering Glauber Approximation (RMSGA) calculations are shown to be consistent with themore » measured asymmetries.« less

Soft tissue nasal asymmetry as an indicator of orofacial cleft predisposition.

PubMed

Zhang, Charles; Miller, Steven F; Roosenboom, Jasmien; Wehby, George L; Moreno Uribe, Lina M; Hecht, Jacqueline T; Deleyiannis, Frederic W B; Christensen, Kaare; Marazita, Mary L; Weinberg, Seth M

2018-06-01

The biological relatives of offspring with nonsyndromic orofacial clefts have been shown to exhibit distinctive facial features, including excess asymmetry, which are hypothesized to indicate the presence of genetic risk factors. The significance of excess soft tissue nasal asymmetry in at-risk relatives is unclear and was examined in the present study. Our sample included 164 unaffected parents from families with a history of orofacial clefting and 243 adult controls. Geometric morphometric methods were used to analyze the coordinates of 15 nasal landmarks collected from three-dimensional facial surface images. Following generalized Procrustes analysis, Procrustes ANOVA and MANOVA tests were applied to determine the type and magnitude of nasal asymmetry present in each group. Group differences in mean nasal asymmetry were also assessed via permutation testing. We found that nasal asymmetry in both parents and controls was directional in nature, although the magnitude of the asymmetry was greater in parents. This was confirmed with permutation testing, where the mean nasal asymmetry was significantly different (p < .0001) between parents and controls. The asymmetry was greatest for midline structures and the nostrils. When subsets of parents were subsequently analyzed and compared (parents with bilateral vs. unilateral offspring; parents with left vs. right unilateral offspring), each group showed a similar pattern of asymmetry and could not be distinguished statistically. Thus, the side of the unilateral cleft (right vs. left) in offspring was not associated with the direction of the nasal asymmetry in parents. © 2018 Wiley Periodicals, Inc.

Beyond apoptosis: The mechanism and function of phosphatidylserine asymmetry in the membrane of activating mast cells

PubMed Central

Rysavy, Noel M.; Shimoda, Lori M. N.; Dixon, Alyssa M.; Speck, Mark; Stokes, Alexander J.; Turner, Helen; Umemoto, Eric Y.

2014-01-01

Loss of plasma membrane asymmetry is a hallmark of apoptosis, but lipid bilayer asymmetry and loss of asymmetry can contribute to numerous cellular functions and responses that are independent of programmed cell death. Exofacial exposure of phosphatidylserine occurs in lymphocytes and mast cells after antigenic stimulation and in the absence of apoptosis, suggesting that there is a functional requirement for phosphatidylserine exposure in immunocytes. In this review we examine current ideas as to the nature of this functional role in mast cell activation. Mechanistically, there is controversy as to the candidate proteins responsible for phosphatidylserine translocation from the internal to external leaflet, and here we review the candidacies of mast cell PLSCR1 and TMEM16F. Finally we examine the potential relationship between functionally important mast cell membrane perturbations and phosphatidylserine exposure during activation. PMID:25759911

Assessment of postural asymmetry in mild to moderate Parkinson's disease.

PubMed

Geurts, A C H; Boonstra, T A; Voermans, N C; Diender, M G; Weerdesteyn, V; Bloem, B R

2011-01-01

Asymmetry of symptoms of Parkinson's disease is clinically most evident for appendicular impairments. For axial impairments such as freezing of gait, asymmetry is less obvious. To date, asymmetries in balance control in PD patients have seldom been studied. Therefore, in this study we investigated whether postural control can be asymmetrically affected in mild to moderate PD patients. Seventeen PD patients were instructed to stand as still and symmetrically as possible on a dual force-plate during two trials. Dynamic postural asymmetry was assessed by comparing the centre-of-pressure velocities between both legs. Results showed that four patients (24%) had dynamic postural asymmetry, even after correcting for weight-bearing asymmetry. Hence, this study suggests that postural control can be asymmetrical in early PD. However, future studies should investigate the prevalence of dynamic postural asymmetry, in a larger group of PD patients. It should also be further investigated whether this approach can be used as a tool to support the initial diagnosis or monitor disease progression, or as an outcome measure for interventions aimed at improving balance in PD. Copyright © 2010 Elsevier B.V. All rights reserved.

Treatment Targets in Inflammatory Bowel Disease: Current Status in Daily Practice.

PubMed

Römkens, Tessa E H; Gijsbers, Kim; Kievit, Wietske; Hoentjen, Frank; Drenth, Joost P H

2016-12-01

Recently, treatment goals in inflammatory bowel disease (IBD) in clinical trials have shifted from mainly symptom-based to more mucosa-driven. Real world data on treatment priorities are lacking. We aimed to investigate the current practice and most commonly used definitions of IBD treatment targets among Dutch gastroenterologists. Dutch gastroenterologists were asked to participate in a computer-based nation-wide survey. We asked questions on demographics, opinion and current practice regarding IBD treatment targets. Twenty-four percent (134/556) of the respondents completed the survey. For both Crohn's disease (CD) (47.3%, 61/129) and ulcerative colitis (UC)(45%, 58/129) the main treatment goal was to achieve and maintain deep remission, defined as clinical, biochemical and endoscopic remission. Seventy-six percent of the participants use mucosal healing (MH) as a potential treatment target for IBD, whereas 22.6% use histological remission. There is no single definition for MH in IBD. The majority use Mayo score ≤ 1 in UC (52%) and 'macroscopic normal mucosa' in CD (66%). More stringent and mucosa-driven treatment targets as 'deep remission' and 'mucosal healing' have found traction in clinical practice. The most commonly used definition for MH in routine practice is endoscopic MAYO score

Between-subject variability in asymmetry analysis of macular thickness.

PubMed

Alluwimi, Muhammed S; Swanson, William H; Malinovsky, Victor E

2014-05-01

To investigate the use of asymmetry analysis to reduce between-subject variability of macular thickness measurements using spectral domain optical coherence tomography. Sixty-three volunteers (33 young subjects [aged 21 to 35 years] and 30 older subjects [aged 45 to 85 years]) free of eye disease were recruited. Macular images were gathered with the Spectralis optical coherence tomography. An overlay 24- by 24-degree grid was divided into five zones per hemifield, and asymmetry analysis was computed as the difference between superior and inferior zone thicknesses. We hypothesized that the lowest variation and the highest density of ganglion cells will be found approximately 3 to 6 degrees from the foveola, corresponding to zones 1 and 2. For each zone and age group, between-subject SDs were compared for retinal thickness versus asymmetry analysis using an F test. To account for repeated comparisons, p < 0.0125 was required for statistical significance. Axial length and corneal curvature were measured with an IOLMaster. For OD, asymmetry analysis reduced between-subject variability in zones 1 and 2 in both groups (F > 3.2, p < 0.001). Standard deviation for zone 1 dropped from 12.0 to 3.0 μm in the young group and from 11.7 to 2.6 μm in the older group. Standard deviation for zone 2 dropped from 13.6 to 5.3 μm in the young group and from 11.1 to 5.8 μm in the older group. Combining all subjects, neither retinal thickness nor asymmetry analysis showed a strong correlation with axial length or corneal curvature (R² < 0.01). Analysis for OS yielded the same pattern of results, as did asymmetry analyses between eyes (F > 3.8, p < 0.0001). Asymmetry analysis reduced between-subject variability in zones 1 and 2. Combining the five zones together produced a higher between-subject variation of the retinal thickness asymmetry analysis; thus, we encourage clinicians to be cautious when interpreting the asymmetry analysis printouts.

Measurement of the parity-violating asymmetry in inclusive electroproduction of π - near the Delta 0 resonance

DOE PAGES

Androic, D.; Armstrong, D. S.; Bailey, S. L.; ...

2012-03-20

The parity-violating (PV) asymmetry of inclusive π - production in electron scattering from a liquid deuterium target was measured at backward angles. The measurement was conducted as a part of the G0 experiment, at a beam energy of 360 MeV. The physics process dominating pion production for these kinematics is quasi-free photoproduction off the neutron via the Δ 0 resonance. In the context of heavy-baryon chiral perturbation theory (HBχPT), this asymmetry is related to a low energy constant d Δ - that characterizes the parity-violating γNΔ coupling. Zhu et al. calculated d Δ - in a model benchmarked by themore » large asymmetries seen in hyperon weak radiative decays, and predicted potentially large asymmetries for this process, ranging from A γ - = -5.2 to +5.2 ppm. The measurement performed in this work leads to A γ - = -0.36 ± 1.06 ± 0.37 ± 0.03 ppm (where sources of statistical, systematic and theoretical uncertainties are included), which would disfavor enchancements considered by Zhu et al. proportional to V ud/V us. The measurement is part of a program of inelastic scattering measurements that were conducted by the G0 experiment, seeking to determine the N-Δ axial transition form-factors using PV electron scattering.« less

Current drive by helicon waves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paul, Manash Kumar; Bora, Dhiraj; ITER Organization, Cadarache Centre-building 519, 131008 St. Paul-Lez-Durance

2009-01-01

Helicity in the dynamo field components of helicon wave is examined during the novel study of wave induced helicity current drive. Strong poloidal asymmetry in the wave magnetic field components is observed during helicon discharges formed in a toroidal vacuum chamber of small aspect ratio. High frequency regime is chosen to increase the phase velocity of helicon waves which in turn minimizes the resonant wave-particle interactions and enhances the contribution of the nonresonant current drive mechanisms. Owing to the strong poloidal asymmetry in the wave magnetic field structures, plasma current is driven mostly by the dynamo-electric-field, which arise due tomore » the wave helicity injection by helicon waves. Small, yet finite contribution from the suppressed wave-particle resonance cannot be ruled out in the operational regime examined. A brief discussion on the parametric dependence of plasma current along with numerical estimations of nonresonant components is presented. A close agreement between the numerical estimation and measured plasma current magnitude is obtained during the present investigation.« less

Tension-compression asymmetry of a rolled Mg-Y-Nd alloy

NASA Astrophysics Data System (ADS)

Song, Bo; Pan, Hucheng; Ren, Weijie; Guo, Ning; Wu, Zehong; Xin, Renlong

2017-07-01

In this work, tension and compression deformation behaviors of rolled and aged Mg-Y-Nd alloys were investigated. The microstructure evolution and plastic deformation mechanism during tension and compression were analyzed by combined use of electron backscatter diffraction and a visco-plastic self-consistent crystal plasticity model. The results show that both rolled and aged Mg-Y-Nd sheets show an extremely low yield asymmetry. Elimination of yield asymmetry can be ascribed to the tilted basal texture and suppression of {10-12} twinning. The rolled sheet has almost no yield asymmetry, however exhibits a remarkable strain-hardening behavior asymmetry. Compressed sample shows lower initial strain hardening rate and keeps higher strain hardening rate at the later stage compared with tension. The strain-hardening asymmetry can be aggravated by aging at 280 C. It is considered the limited amount of twins in compression plays the critical role in the strain hardening asymmetry. Finally, the relevant mechanism was analyzed and discussed.

Mercury exposure may influence fluctuating asymmetry in waterbirds.

PubMed

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

2017-06-01

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

North-south asymmetry in the magnetic deflection of polar coronal hole jets

NASA Astrophysics Data System (ADS)

Nisticò, G.; Zimbardo, G.; Patsourakos, S.; Bothmer, V.; Nakariakov, V. M.

2015-11-01

Context. Measurements of the sunspots area, of the magnetic field in the interplanetary medium, and of the heliospheric current sheet (HCS) position, reveal a possible north-south (N-S) asymmetry in the magnetic field of the Sun. This asymmetry could cause the bending of the HCS of the order of 5-10 deg in the southward direction, and it appears to be a recurrent characteristic of the Sun during the minima of solar activity. Aims: We study the N-S asymmetry as inferred from measurements of the deflection of polar coronal hole jets when they propagate throughout the corona. Methods: Since the corona is an environment where the magnetic pressure is greater than the kinetic pressure (β ≪ 1), we can assume that the magnetic field controls the dynamics of plasma. On average, jets follow magnetic field lines during their propagation, highlighting their local direction. We measured the position angles at 1 R⊙ and at 2 R⊙ of 79 jets, based on the Solar TErrestrial RElations Observatory (STEREO) ultraviolet and white-light coronagraph observations during the solar minimum period March 2007-April 2008. The average jet deflection is studied both in the plane perpendicular to the line of sight and, for a reduced number of jets, in 3D space. The observed jet deflection is studied in terms of an axisymmetric magnetic field model comprising dipole (g1), quadrupole (g2), and esapole (g3) moments. Results: We found that the propagation of the jets is not radial, which is in agreement with the deflection due to magnetic field lines. Moreover, the amount of the deflection is different between jets over the north and those from the south pole. A comparison of jet deflections and field line tracing shows that a ratio g2/g1 ≃ -0.5 for the quadrupole and a ratio g3/g1 ≃ 1.6-2.0 for the esapole can describe the field. The presence of a non-negligible quadrupole moment confirms the N-S asymmetry of the solar magnetic field for the considered period. Conclusions: We find that the

Trust in the safety of tourist destinations: hard to gain, easy to lose? New insights on the asymmetry principle.

PubMed

Eitzinger, Claudia; Wiedemann, Peter M

2008-08-01

According to the asymmetry principle of trust, negative events decrease trust to a much higher extent than positive events increase trust. The study at hand intended to verify whether this notion of asymmetry holds true with respect to trust in the safety of tourist destinations. Thus, in contrast to previous research that analyzed trust asymmetry in the context of involuntary technological risks, the present study evaluates the validity of the asymmetry principle of trust in the context of voluntary tourism risks. The hypothesis that negative or risky information on destination safety (absence of proper safety measures and conditions) has a higher impact on distrust than, conversely, positive or nonrisk information on destination safety (provision of proper safety measures and conditions) has on trust was tested in an online survey (N= 640). In contrast to the asymmetry pattern found by Slovic (1993), results of the current work suggest symmetry rather than asymmetry of trust. The presence of proper safety measures and conditions (positive or nonrisk information) was found to have at least the same-and in some cases an even higher-impact on trust than the absence of such measures and conditions (negative or risky information) had on distrust. Findings provide empirical evidence for the thesis that the prevalence of trust asymmetry is dependent on the risk source and demonstrate that trust is symmetric rather than asymmetric in the context of voluntary tourism risks. Furthermore, results imply an influence of positive versus negative expectations as well as of prior trusting relationships on the occurrence of the asymmetry principle.

Audiometric asymmetry and tinnitus laterality.

PubMed

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

2012-05-01

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

Hemispheric and facial asymmetry: faces of academe.

PubMed

Smith, W M

1998-11-01

Facial asymmetry (facedness) of selected academic faculty members was studied in relation to brain asymmetry and cognitive specialization. Comparisons of facedness were made among humanities faculty (H), faculty members of mathematics and physics (M-P), psychologists (P), and a group of randomly selected individuals (R). Facedness was defined in terms of the relative sizes (in square centimeters) of the two hemifaces. It was predicted that the four groups would show differences in facedness, namely, H, right face bias; M-P, left face bias; P, no bias; and R, no bias. The predictions were confirmed, and the results interpreted in terms of known differences in hemispheric specialization of cognitive functions as they relate to the dominant cognitive activity of each of the different groups. In view of the contralateral control of the two hemifaces (below the eyes) by the two hemispheres of the brain, the two sides of the face undergo differential muscular development, thus creating facial asymmetry. Other factors, such as gender, also may affect facial asymmetry. Suggestions for further research on facedness are discussed.

Frontal Brain Asymmetry and Willingness to Pay.

PubMed

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

2018-01-01

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

Semantics is crucial for the right-hemisphere involvement in metaphor processing: evidence from mouth asymmetry during speaking.

PubMed

Argyriou, Paraskevi; Byfield, Sarah; Kita, Sotaro

2015-01-01

Research on the neural basis of metaphor provides contradicting evidence about the role of right and left hemispheres. We used the mouth-opening asymmetry technique to investigate the relative involvement of the two hemispheres whilst right-handed healthy male participants explained the meaning of English phrases. This technique is based on the contralateral cortical control of the facial musculature and reflects the relative hemispheric involvement during different cognitive tasks. In particular, right-handers show a right-sided mouth asymmetry (right side of the mouth opens wider than the left) during linguistic tasks, thus reflecting the left-hemisphere specialization for language. In the current study, we compared the right-sided mouth asymmetry during metaphor explanation (e.g., explain the meaning of the phrase "to spin a yarn") and concrete explanation (e.g., explain the meaning of the phrase "to spin a golf ball") and during the production of content and function words. The expected right-sided mouth asymmetry reduced during metaphorical compared to concrete explanations suggesting the relative right-hemispheric involvement for metaphor processing. Crucially, this right-sided mouth asymmetry reduction was particularly pronounced for the production of content words. Thus, we concluded that semantics is crucial to the right-hemispheric involvement for metaphorical speech production.

Functional asymmetry of posture and body system regulation

NASA Technical Reports Server (NTRS)

Boloban, V. N.; Otsupok, A. P.

1980-01-01

The manifestation of functional asymmetry during the regulation of an athlete's posture and a system of bodies and its effect on the execution of individual and group acrobatic exercises were studied. Functional asymmetry of posture regulation was recorded in acrobats during the execution of individual and group exercises. It was shown that stability is maintained at the expense of bending and twisting motions. It is important to consider whether the functional asymmetry of posture regulation is left or right sided in making up pairs and groups of acrobats.

Asymmetries of the arcuate fasciculus in monozygotic twins: genetic and nongenetic influences.

PubMed

Häberling, Isabelle S; Badzakova-Trajkov, Gjurgjica; Corballis, Michael C

2013-01-01

We assessed cerebral asymmetry for language in 35 monozygotic twin pairs. Using DTI, we reconstructed the arcuate fasciculus in each twin. Among the male twins, right-handed pairs showed greater left-sided asymmetry of connectivity in the arcuate fasciculus than did those with discordant handedness, and within the discordant group the right-handers had greater left-sided volume asymmetry of the arcuate fasciculus than did their left-handed co-twins. There were no such effects in the female twins. Cerebral asymmetry for language showed more consistent results, with the more left-cerebrally dominant twins also showing more leftward asymmetry of high anisotropic fibers in the arcuate fasciculus, a result applying equally to female as to male twins. Reversals of arcuate fasciculus asymmetry were restricted to pairs discordant for language dominance, with the left-cerebrally dominant twins showing leftward and the right-cerebrally dominant twins rightward asymmetry of anisotropic diffusion in the arcuate fasciculus. Because monozygotic twin pairs share the same genotype, our results indicate a strong nongenetic component in arcuate fasciculus asymmetry, particularly in those discordant for cerebral asymmetry.

Use of Targeted Therapeutics in Epithelial Ovarian Cancer: A Review of Current Literature and Future Directions.

PubMed

Vetter, Monica Hagan; Hays, John L

2018-03-01

Epithelial ovarian cancer (EOC) is the leading cause of gynecologic cancer death in the United States. Most patients will ultimately fail platinum-based chemotherapy and have the disease recur. Interest is increasing in the use of targeted therapies in the treatment of EOC. This review focuses on the current use of targeted therapeutics in EOC as well as future directions. A literature search of Medline and PubMed was conducted (January 2000-October 2017) to identify recent reports of targeted drugs in EOC. A wide range of targeted therapeutics is currently being used as both monotherapy and in combination in the treatment of EOC. Clinically, the most commonly used classes of drugs currently are antiangiogenics and poly (ADP-ribose) polymerase inhibitors. However, a number of drugs in varying stages in development target a wide range of biochemical pathways. Activity and response rates of these drugs vary greatly. Questions continue about combination drug therapy and appropriate patient selection. The use of targeted therapeutics in the treatment of EOC, both as monotherapy and in combination, will continue to expand as more mechanisms of tumorigenesis are identified. Multiple clinical trials of a wide range of targeted therapeutics are currently ongoing. Evidence-based selection of drug targets and appropriate patient populations will allow strategic application of targeted therapeutics. Copyright © 2018 Elsevier HS Journals, Inc. All rights reserved.

Switching between global and local levels: the level repetition effect and its hemispheric asymmetry

PubMed Central

Kéïta, Luc; Bedoin, Nathalie; Burack, Jacob A.; Lepore, Franco

2014-01-01

The global level of hierarchical stimuli (Navon’s stimuli) is typically processed quicker and better than the local level; further differential hemispheric dominance is described for local (left hemisphere, LH) and global (right hemisphere, RH) processing. However, neuroimaging and behavioral data indicate that stimulus category (letter or object) could modulate the hemispheric asymmetry for the local level processing. Besides, when the targets are unpredictably displayed at the global or local level, the participant has to switch between levels, and the magnitude of the switch cost increases with the number of repeated-level trials preceding the switch. The hemispheric asymmetries associated with level switching is an unresolved issue. LH areas may be involved in carrying over the target level information in case of level repetition. These areas may also largely participate in the processing of level-changed trials. Here we hypothesized that RH areas underly the inhibitory mechanism performed on the irrelevant level, as one of the components of the level switching process. In an experiment using a within-subject design, hierarchical stimuli were briefly presented either to the right or to the left visual field. 32 adults were instructed to identify the target at the global or local level. We assessed a possible RH dominance for the non-target level inhibition by varying the attentional demands through the manipulation of level repetitions (two or gour repeated-level trials before the switch). The behavioral data confirmed a LH specialization only for the local level processing of letter-based stimuli, and detrimental effect of increased level repetitions before a switch. Further, data provides evidence for a RH advantage in inhibiting the non-target level. Taken together, the data supports the notion of the existence of multiple mechanisms underlying level-switch effects. PMID:24723903

Correlation between amygdala BOLD activity and frontal EEG asymmetry during real-time fMRI neurofeedback training in patients with depression

PubMed Central

Zotev, Vadim; Yuan, Han; Misaki, Masaya; Phillips, Raquel; Young, Kymberly D.; Feldner, Matthew T.; Bodurka, Jerzy

2016-01-01

Real-time fMRI neurofeedback (rtfMRI-nf) is an emerging approach for studies and novel treatments of major depressive disorder (MDD). EEG performed simultaneously with an rtfMRI-nf procedure allows an independent evaluation of rtfMRI-nf brain modulation effects. Frontal EEG asymmetry in the alpha band is a widely used measure of emotion and motivation that shows profound changes in depression. However, it has never been directly related to simultaneously acquired fMRI data. We report the first study investigating electrophysiological correlates of the rtfMRI-nf procedure, by combining the rtfMRI-nf with simultaneous and passive EEG recordings. In this pilot study, MDD patients in the experimental group (n = 13) learned to upregulate BOLD activity of the left amygdala using an rtfMRI-nf during a happy emotion induction task. MDD patients in the control group (n = 11) were provided with a sham rtfMRI-nf. Correlations between frontal EEG asymmetry in the upper alpha band and BOLD activity across the brain were examined. Average individual changes in frontal EEG asymmetry during the rtfMRI-nf task for the experimental group showed a significant positive correlation with the MDD patients' depression severity ratings, consistent with an inverse correlation between the depression severity and frontal EEG asymmetry at rest. The average asymmetry changes also significantly correlated with the amygdala BOLD laterality. Temporal correlations between frontal EEG asymmetry and BOLD activity were significantly enhanced, during the rtfMRI-nf task, for the amygdala and many regions associated with emotion regulation. Our findings demonstrate an important link between amygdala BOLD activity and frontal EEG asymmetry during emotion regulation. Our EEG asymmetry results indicate that the rtfMRI-nf training targeting the amygdala is beneficial to MDD patients. They further suggest that EEG-nf based on frontal EEG asymmetry in the alpha band would be compatible with the amygdala

Hand preference and magnetic resonance imaging asymmetries of the central sulcus.

PubMed

Foundas, A L; Hong, K; Leonard, C M; Heilman, K M

1998-04-01

Hand preference is perhaps the most evident behavioral asymmetry observed in humans. Anatomic brain asymmetries that may be associated with hand preference have not been extensively studied, and no clear relationship between asymmetries of the motor system and hand preference have been established. Therefore, using volumetric magnetic resonance imaging methodologies, the surface area of the hand representation was measured along the length of the central sulcus in 15 consistent right- and 15 left-handers matched for age and gender. There was a significant leftward asymmetry of the motor hand area of the precentral gyrus in the right-handers, but no directional asymmetry was found in the left-handers. When asymmetry quotients were computed to determine the distribution of interhemispheric asymmetries, the left motor bank was greater than the right motor bank in 9 of 15 right-handers, the right motor bank was greater than the left motor bank in 3 of 15 right-handers, and the motor banks were equal in 3 of 15 right-handers. In contrast, among left-handers, the left motor bank was greater than the right motor bank in 5 of 15, the right motor bank was greater than the left motor bank in 5 of 15, and the motor banks were equal in 5 of 15. Although no direct measure of motor dexterity and skill was performed, these data suggest that anatomic asymmetries of the motor hand area may be related to hand preference because of the differences in right-handers and left-handers. Furthermore, the predominant leftward asymmetry in right-handers and the random distribution of asymmetries in the left-handers support Annett's right-shift theory. It is unclear, however, whether these asymmetries are the result of preferential hand use or are a reflection of a biologic preference to use one limb over the other.

The association between infantile postural asymmetry and unsettled behaviour in babies.

PubMed

Ellwood, Julie; Ford, Michael; Nicholson, Alf

2017-12-01

Unsettled infant behaviour is a common problem of infancy without known aetiology or clearly effective management. Some manual therapists propose that musculoskeletal dysfunction contributes to unsettled infant behaviour, yet reported improvement following treatment is anecdotal. The infantile postural asymmetry measurement scale is a tool which measures infantile asymmetry, a form of musculoskeletal dysfunction. The first part of the study aimed to investigate its reliability and validity for measuring infantile postural asymmetry. This study also aimed to investigate whether there was an association between infantile postural asymmetry and unsettled infant behaviour and whether an association was mediated by, or confounded with, the demographic variables of age, sex, parity, birth weight and weight gain in 12- to 16-week-old infants. Fifty-eight infants were recruited and a quantitative cross-sectional observational design was used. An association between unsettled behaviour and infantile postural asymmetry was not found. A significant difference between high and low cervical rotation deficit groups for surgency was detected in female babies and needs further examination. Questions remain regarding the construct validity of the infantile postural asymmetry scale. No association between unsettled infant behaviour and infantile postural asymmetry was found in 12- to 16-week-old infants. The influence of sex on the interaction between infantile postural asymmetry and infant behaviour needs further examination. An association between unsettled infant behaviour and infantile postural asymmetry is still unproven. What is known: • Unsettled infant behaviour has a considerable impact on many family situations. • Identifying a definitive cause has been a source of much examination and research. Many different hypotheses have been suggested yet much is still unknown. What is new: • The association between unsettled infant behaviour and infantile postural asymmetry is

Pelvic bone asymmetry in 323 study participants receiving abdominal CT scans.

PubMed

Badii, Maziar; Shin, Sonya; Torreggiani, William C; Jankovic, Bojana; Gustafson, Paul; Munk, Peter L; Esdaile, John M

2003-06-15

Retrospective review of all CT scans of pelvis and abdomen performed at our institution in October and November 2000. To determine the prevalence and extent of radiographic pelvic asymmetry in a population of patients not preselected for having low back pain. Pelvic asymmetry refers to asymmetric positioning of landmarks on the two sides of the pelvis and may have a structural or functional etiology. Pelvic asymmetry can be associated with the presence of true leg length discrepancy, lead to false diagnosis or inaccurate measurement of leg length discrepancy, or itself be independently associated with back pain. Although the prevalence of pelvic asymmetry has been reported in patients with back pain to be 24-91%, its prevalence in the general population is not known. A total of 323 consecutive CT scans of the pelvis/abdomen were assessed for pelvic asymmetry by one of three examiners. Pelvic asymmetry was defined as an unequal distance from the iliac crests to the acetabuli bilaterally, measured on the anteroposterior scout view of the CT scan. Measurements made on 30 randomly selected scans by the three examiners were used to assess interrater reliability of the measurement method. Pelvic asymmetry ranged in magnitude from -11 mm to 7 mm [right pelvis (mm) - left pelvis (mm)]. Pelvic asymmetry was >5 mm in 17 of 323 (5.3%) and >10 mm in 2 of 323 (0.6%) of the subjects; 172 of 323 (53.3%) had a smaller right hemipelvis (mean asymmetry = -3.0 mm). A total of 95 of 323 (29.4%) had a smaller left hemipelvis (mean asymmetry = 2.1 mm). The intraclass correlation coefficient [ICC(2,1)] between the three observers was high (0.91). Pelvic asymmetry of >5 mm was uncommon, with a prevalence of approximately 5% in the population studied. CT scanography was found to be a practical and reliable method for the assessment of suspected pelvic asymmetry.

Systemic sclerosis and localized scleroderma--current concepts and novel targets for therapy.

PubMed

Distler, Oliver; Cozzio, Antonio

2016-01-01

Systemic sclerosis (SSc) is a chronic autoimmune disease with a high morbidity and mortality. Skin and organ fibrosis are key manifestations of SSc, for which no generally accepted therapy is available. Thus, there is a high unmet need for novel anti-fibrotic therapeutic strategies in SSc. At the same time, important progress has been made in the identification and characterization of potential molecular targets in fibrotic diseases over the recent years. In this review, we have selected four targeted therapies, which are tested in clinical trials in SSc, for in depths discussion of their preclinical characterization. Soluble guanylate cyclase (sGC) stimulators such as riociguat might target both vascular remodeling and tissue fibrosis. Blockade of interleukin-6 might be particularly promising for early inflammatory stages of SSc. Inhibition of serotonin receptor 2b signaling links platelet activation to tissue fibrosis. Targeting simultaneously multiple key molecules with the multityrosine kinase-inhibitor nintedanib might be a promising approach in complex fibrotic diseases such as SSc, in which many partially independent pathways are activated. Herein, we also give a state of the art overview of the current classification, clinical presentation, diagnostic approach, and treatment options of localized scleroderma. Finally, we discuss whether the novel targeted therapies currently tested in SSc could be used for localized scleroderma.

Sparse aperture masking interferometry survey of transitional discs. Search for substellar-mass companions and asymmetries in their parent discs

NASA Astrophysics Data System (ADS)

Willson, M.; Kraus, S.; Kluska, J.; Monnier, J. D.; Ireland, M.; Aarnio, A.; Sitko, M. L.; Calvet, N.; Espaillat, C.; Wilner, D. J.

2016-10-01

Context. Transitional discs are a class of circumstellar discs around young stars with extensive clearing of dusty material within their inner regions on 10s of au scales. One of the primary candidates for this kind of clearing is the formation of planet(s) within the disc that then accrete or clear their immediate area as they migrate through the disc. Aims: The goal of this survey was to search for asymmetries in the brightness distribution around a selection of transitional disc targets. We then aimed to determine whether these asymmetries trace dynamically-induced structures in the disc or the gap-opening planets themselves. Methods: Our sample included eight transitional discs. Using the Keck/NIRC2 instrument we utilised the Sparse Aperture Masking (SAM) interferometry technique to search for asymmetries indicative of ongoing planet formation. We searched for close-in companions using both model fitting and interferometric image reconstruction techniques. Using simulated data, we derived diagnostics that helped us to distinguish between point sources and extended asymmetric disc emission. In addition, we investigated the degeneracy between the contrast and separation that appear for marginally resolved companions. Results: We found FP Tau to contain a previously unseen disc wall, and DM Tau, LkHα330, and TW Hya to contain an asymmetric signal indicative of point source-like emission. We placed upper limits on the contrast of a companion in RXJ 1842.9-3532 and V2246 Oph. We ruled the asymmetry signal in RXJ 1615.3-3255 and V2062 Oph to be false positives. In the cases where our data indicated a potential companion we computed estimates for the value of McṀc and found values in the range of . Conclusions: We found significant asymmetries in four targets. Of these, three were consistent with companions. We resolved a previously unseen gap in the disc of FP Tau extending inwards from approximately 10 au. Based on observations made with the Keck observatory

The validity of individual frontal alpha asymmetry EEG neurofeedback

PubMed Central

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

2016-01-01

Frontal asymmetry in alpha oscillations is assumed to be associated with psychopathology and individual differences in emotional responding. Brain-activity-based feedback is a promising tool for the modulation of cortical activity. Here, we validated a neurofeedback protocol designed to change relative frontal asymmetry based on individual alpha peak frequencies, including real-time average referencing and eye-correction. Participants (N = 60) were randomly assigned to a right, left or placebo neurofeedback group. Results show a difference in trainability between groups, with a linear change in frontal alpha asymmetry over time for the right neurofeedback group during rest. Moreover, the asymmetry changes in the right group were frequency and location specific, even though trainability did not persist at 1 week and 1 month follow-ups. On the behavioral level, subjective stress on the second test day was reduced in the left and placebo neurofeedback groups, but not in the right neurofeedback group. We found individual differences in trainability that were dependent on training group, with participants in the right neurofeedback group being more likely to change their frontal asymmetry in the desired direction. Individual differences in trainability were also reflected in the ability to change frontal asymmetry during the feedback. PMID:26163671

Gaussian quantum steering and its asymmetry in curved spacetime

NASA Astrophysics Data System (ADS)

Wang, Jieci; Cao, Haixin; Jing, Jiliang; Fan, Heng

2016-06-01

We study Gaussian quantum steering and its asymmetry in the background of a Schwarzschild black hole. We present a Gaussian channel description of quantum state evolution under the influence of Hawking radiation. We find that thermal noise introduced by the Hawking effect will destroy the steerability between an inertial observer Alice and an accelerated observer Bob who hovers outside the event horizon, while it generates steerability between Bob and a hypothetical observer anti-Bob inside the event horizon. Unlike entanglement behaviors in curved spacetime, here the steering from Alice to Bob suffers from a "sudden death" and the steering from anti-Bob to Bob experiences a "sudden birth" with increasing Hawking temperature. We also find that the Gaussian steering is always asymmetric and the maximum steering asymmetry cannot exceed ln 2 , which means the state never evolves to an extremal asymmetry state. Furthermore, we obtain the parameter settings that maximize steering asymmetry and find that (i) s =arccosh cosh/2r 1 -sinh2r is the critical point of steering asymmetry and (ii) the attainment of maximal steering asymmetry indicates the transition between one-way steerability and both-way steerability for the two-mode Gaussian state under the influence of Hawking radiation.

Shifting brain asymmetry: the link between meditation and structural lateralization

PubMed Central

Kurth, Florian; MacKenzie-Graham, Allan; Toga, Arthur W.

2015-01-01

Previous studies have revealed an increased fractional anisotropy and greater thickness in the anterior parts of the corpus callosum in meditation practitioners compared with control subjects. Altered callosal features may be associated with an altered inter-hemispheric integration and the degree of brain asymmetry may also be shifted in meditation practitioners. Therefore, we investigated differences in gray matter asymmetry as well as correlations between gray matter asymmetry and years of meditation practice in 50 long-term meditators and 50 controls. We detected a decreased rightward asymmetry in the precuneus in meditators compared with controls. In addition, we observed that a stronger leftward asymmetry near the posterior intraparietal sulcus was positively associated with the number of meditation practice years. In a further exploratory analysis, we observed that a stronger rightward asymmetry in the pregenual cingulate cortex was negatively associated with the number of practice years. The group difference within the precuneus, as well as the positive correlations with meditation years in the pregenual cingulate cortex, suggests an adaptation of the default mode network in meditators. The positive correlation between meditation practice years and asymmetry near the posterior intraparietal sulcus may suggest that meditation is accompanied by changes in attention processing. PMID:24643652

Regulation of branching dynamics by axon-intrinsic asymmetries in Tyrosine Kinase Receptor signaling

PubMed Central

Zschätzsch, Marlen; Oliva, Carlos; Langen, Marion; De Geest, Natalie; Özel, Mehmet Neset; Williamson, W Ryan; Lemon, William C; Soldano, Alessia; Munck, Sebastian; Hiesinger, P Robin; Sanchez-Soriano, Natalia; Hassan, Bassem A

2014-01-01

Axonal branching allows a neuron to connect to several targets, increasing neuronal circuit complexity. While axonal branching is well described, the mechanisms that control it remain largely unknown. We find that in the Drosophila CNS branches develop through a process of excessive growth followed by pruning. In vivo high-resolution live imaging of developing brains as well as loss and gain of function experiments show that activation of Epidermal Growth Factor Receptor (EGFR) is necessary for branch dynamics and the final branching pattern. Live imaging also reveals that intrinsic asymmetry in EGFR localization regulates the balance between dynamic and static filopodia. Elimination of signaling asymmetry by either loss or gain of EGFR function results in reduced dynamics leading to excessive branch formation. In summary, we propose that the dynamic process of axon branch development is mediated by differential local distribution of signaling receptors. DOI: http://dx.doi.org/10.7554/eLife.01699.001 PMID:24755286

Accuracy of saccades to remembered targets as a function of body orientation in space

NASA Technical Reports Server (NTRS)

Vogelstein, Joshua T.; Snyder, Lawrence H.; Angelaki, Dora E.

2003-01-01

A vertical asymmetry in memory-guided saccadic eye movements has been previously demonstrated in humans and in rhesus monkeys. In the upright orientation, saccades generally land several degrees above the target. The origin of this asymmetry has remained unknown. In this study, we investigated whether the asymmetry in memory saccades is dependent on body orientation in space. Thus animals performed memory saccades in four different body orientations: upright, left-side-down (LSD), right-side-down (RSD), and supine. Data in all three rhesus monkeys confirm previous observations regarding a significant upward vertical asymmetry. Saccade errors made from LSD and RSD postures were partitioned into components made along the axis of gravity and along the vertical body axis. Up/down asymmetry persisted only in body coordinates but not in gravity coordinates. However, this asymmetry was generally reduced in tilted positions. Therefore the upward bias seen in memory saccades is egocentric although orientation in space might play a modulatory role.

Amplitude and polarization asymmetries in a ring laser

NASA Technical Reports Server (NTRS)

Campbell, L. L.; Buholz, N. E.

1971-01-01

Asymmetric amplitude effects between the oppositely directed traveling waves in a He-Ne ring laser are analyzed both theoretically and experimentally. These effects make it possible to detect angular orientations of an inner-cavity bar with respect to the plane of the ring cavity. The amplitude asymmetries occur when a birefringent bar is placed in the three-mirror ring cavity, and an axial magnetic field is applied to the active medium. A simplified theoretical analysis is performed by using a first order perturbation theory to derive an expression for the polarization of the active medium, and a set of self-consistent equations are derived to predict threshold conditions. Polarization asymmetries between the oppositely directed waves are also predicted. Amplitude asymmetries similar in nature to those predicted at threshold occur when the laser is operating in 12-15 free-running modes, and polarization asymmetry occurs simultaneously.

Measurement of the Beam Asymmetry Σ in π0- and η-photoproduction off the proton

NASA Astrophysics Data System (ADS)

Afzal, Farah Noreen

The beam asymmetry Σ was measured for a beam energy range of 1100 to 1820 MeV with the CBELSA/TAPS experiment at the electron stretcher accelerator ELSA using a linearly polarized photon beam and a liquid hydrogen target. The data were analyzed for single π0- and η-photoproduction, respectively. Preliminary results are presented and compared to existing data and different partial wave analysis solutions.

Charge conjugation symmetry in proton--antiproton interactions at 5. 4 GeV energy. [5. 4 GeV, asymmetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whittaker, J D

1977-10-01

The charge conjugation symmetry of the reaction anti pp- ..-->.. ..pi../sup +-/ + X was checked at radical s = 5.4 GeV. The measurement was made with a double arm spectrometer, with each arm triggered independently. Each spectrometer arm had an acceptance of 15 millisteradians and subtended an angular range of 16 to 20/sup 0/ in the lab, 77 to 91/sup 0/ in the pion center of mass system (CMS). The asymmetry (N/sup +/ - N/sup -/)/(N/sup +/ + N/sup -/) was determined at 90/sup 0/ CMS over a P/sub t/ range of .5 to 2.7 GeV/c. Corrections were mademore » for target empty, for pions in the incident beam, and for particle misidentification in the spectrometer. The resulting symmetry was .0084 +- .0090; consistent with zero. The asymmetry introduced by differential pion absorption in the spectrometer was estimated to be .0021. In the P/sub t/ regions of .48 to .67 to 1.00 and 1.00 to 2.7 GeV/c, the asymmetries were .0037 +- .0115, .0178 +- .0145, and -.0025 +- .0311, respectively. The corresponding limits on the amplitude ratio V = Re (C-nonconserving amplitude)/(C-conserving amplitude) are one half of the asymmetry limits.« less

Characterization of Asymmetry in Magnetoacoustic Emission Burst by Numerical Processes

NASA Technical Reports Server (NTRS)

Namkung, M.; Fulton, J. P.; Wincheski, B.; DeNale, R.

1991-01-01

It has been well known that the pattern of the magnetoacoustic emission (MAE) burst observed during the sweep over one half-cycle of the hysteresis loop becomes asymmetric depending on the strength of the magnetic domain wall-defect interaction and the state of residual stresses in a ferromagnet. The ascending asymmetry due to the former has been observed at a very low frequency (.7 Hz) of applied AC magnetic field at a given amplitude. The descending asymmetry due to uniaxial compressive stress has been typically observed at the AC applied magnetic field frequency of 20 Hz. The physical interpretation of both types of asymmetry has been well established. It is, however, necessary to perform investigations of the dependence of asymmetry on externally controlled parameters such as the amplitude and frequency of the AC applied magnetic fields. The purpose of the present study is therefore to devise a mathematical means that describes the degree of asymmetry of the MAE burst and apply this scheme to investigate the AC magnetic field amplitude dependence of the asymmetry.

Preliminary Results of T and F Asymmetries for KLambda Photoproduction from the Proton

NASA Astrophysics Data System (ADS)

Walford, Natalie; Klein, Franz

2013-04-01

The search for undiscovered excited states of the nucleon continues to be a focus of experiments at Jefferson Lab. A large effort has been launched using the CLAS detector to provide the database, which will allow nearly model-independent partial wave analyses to be carried out in the search for such states. Polarization observables play a crucial role in this effort, as they are essential in disentangling overlapping resonant and non-resonant amplitudes. Recent coupled-channel analyses [1] have found strong sensitivity of the K-Lambda channel to several higher mass nucleon resonances. In 2010, double-polarization data were taken at JLab using circularly polarized photons incident on a transversely polarized frozen spin target (FROST) [2] comprising butanol, operated at the low temperature of 30mK. The reaction products were detected in CLAS using tagged photons. We will present preliminary data of the T and F asymmetries of the K-Lambda final state with comparisons to predictions of recent multipole analyses. There are very few published measurements of the T asymmetry and none of the F asymmetry for the K-Lambda channel. This work is the first of its kind and will significantly broaden the world database for this reaction.[4pt] [1] A.V. Anisovich et al., Eur. Phys. J. A48 (2012) 15.2] C.D. Keith et al., Nucl. Instr. Meth. A694 (2012) 27.

Cortical asymmetries in unaffected siblings of patients with obsessive-compulsive disorder.

PubMed

Peng, Ziwen; Li, Gang; Shi, Feng; Shi, Changzheng; Yang, Qiong; Chan, Raymond C K; Shen, Dinggang

2015-12-30

Obsessive-compulsive disorder (OCD) is considered to be associated with atypical brain asymmetry. However, no study has examined the asymmetry in OCD from the perspective of cortical morphometry. This study is aimed to describe the characteristics of cortical asymmetry in OCD patients, and to investigate whether these features exist in their unaffected siblings - a vital step in identifying putative endophenotypes for OCD. A total of 48 subjects (16 OCD patients, 16 unaffected siblings, and 16 matched controls) were recruited who had complete magnetic resonance imaging scans. Left-right hemispheric asymmetries of cortical thickness were measured using a surface-based threshold-free cluster enhancement method. OCD patients and siblings both showed leftward asymmetries of cortical thickness in the anterior cingulate cortex (ACC), which showed a significant positive correlation with compulsive subscale scores. In addition, siblings and healthy controls showed significantly decreased leftward asymmetries in the orbitofrontal cortex (OFC), and the decreased leftward bias in the OFC was accompanied by lower scales on the Yale-Brown Obsessive-Compulsive Scale. To sum up, leftward asymmetries of cortical thickness in the ACC may represent an endophenotype of increased hereditary risk for OCD, while decreased leftward asymmetries of cortical thickness in the OFC may represent a protective factor. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The role of frontal EEG asymmetry in post-traumatic stress disorder.

PubMed

Meyer, Thomas; Smeets, Tom; Giesbrecht, Timo; Quaedflieg, Conny W E M; Smulders, Fren T Y; Meijer, Ewout H; Merckelbach, Harald L G J

2015-05-01

Frontal alpha asymmetry, a biomarker derived from electroencephalography (EEG) recordings, has often been associated with psychological adjustment, with more left-sided frontal activity predicting approach motivation and lower levels of depression and anxiety. This suggests high relevance to post-traumatic stress disorder (PTSD), a disorder comprising anxiety and dysphoria symptoms. We review this relationship and show that frontal asymmetry can be plausibly linked to neuropsychological abnormalities seen in PTSD. However, surprisingly few studies (k = 8) have directly addressed frontal asymmetry in PTSD, mostly reporting that trait frontal asymmetry has little (if any) predictive value. Meanwhile, preliminary evidence suggest that state-dependent asymmetry during trauma-relevant stimulation distinguishes PTSD patients from resilient individuals. Thus, exploring links between provocation-induced EEG asymmetry and PTSD appears particularly promising. Additionally, we recommend more fine-grained analyses into PTSD symptom clusters in relation to frontal asymmetry. Finally, we highlight hypotheses that may guide future research and help to fully apprehend the practical and theoretical relevance of this biological marker. Copyright © 2015 Elsevier B.V. All rights reserved.

New tuning method of the low-mode asymmetry for ignition capsule implosions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gu, Jianfa, E-mail: gu-jianfa@iapcm.ac.cn; Dai, Zhensheng; Zou, Shiyang

2015-12-15

In the deuterium-tritium inertial confinement fusion implosion experiments on the National Ignition Facility, the hot spot and the surrounding main fuel layer show obvious P2 asymmetries. This may be caused by the large positive P2 radiation flux asymmetry during the peak pulse resulting form the poor propagation of the inner laser beam in the gas-filled hohlraum. The symmetry evolution of ignition capsule implosions is investigated by applying P2 radiation flux asymmetries during different time intervals. A series of two-dimensional simulation results show that a positive P2 flux asymmetry during the peak pulse results in a positive P2 shell ρR asymmetry;more » while an early time positive P2 flux asymmetry causes a negative P2 in the fuel ρR shape. The opposite evolution behavior of shell ρR asymmetry is used to develop a new tuning method to correct the radiation flux asymmetry during the peak pulse by adding a compensating same-phased P2 drive asymmetry during the early time. The significant improvements of the shell ρR symmetry, hot spot shape, hot spot internal energy, and neutron yield indicate that the tuning method is quite effective. The similar tuning method can also be used to control the early time drive asymmetries.« less

The functional and structural asymmetries of the superior temporal sulcus.

PubMed

Specht, Karsten; Wigglesworth, Philip

2018-02-01

The superior temporal sulcus (STS) is an anatomical structure that increasingly interests researchers. This structure appears to receive multisensory input and is involved in several perceptual and cognitive core functions, such as speech perception, audiovisual integration, (biological) motion processing and theory of mind capacities. In addition, the superior temporal sulcus is not only one of the longest sulci of the brain, but it also shows marked functional and structural asymmetries, some of which have only been found in humans. To explore the functional-structural relationships of these asymmetries in more detail, this study combines functional and structural magnetic resonance imaging. Using a speech perception task, an audiovisual integration task, and a theory of mind task, this study again demonstrated an involvement of the STS in these processes, with an expected strong leftward asymmetry for the speech perception task. Furthermore, this study confirmed the earlier described, human-specific asymmetries, namely that the left STS is longer than the right STS and that the right STS is deeper than the left STS. However, this study did not find any relationship between these structural asymmetries and the detected brain activations or their functional asymmetries. This can, on the other hand, give further support to the notion that the structural asymmetry of the STS is not directly related to the functional asymmetry of the speech perception and the language system as a whole, but that it may have other causes and functions. © 2018 The Authors. Scandinavian Journal of Psychology published by Scandinavian Psychological Associations and John Wiley & Sons Ltd.

Auxin asymmetry during gravitropism by tomato hypocotyls

NASA Technical Reports Server (NTRS)

Harrison, M. A.; Pickard, B. G.

1989-01-01

Gravitropic asymmetry of auxin was observed in hypocotyls of tomato (Lycopersicon esculentum Mill.) soon after horizontal placement: the ratio of apically supplied [3H]IAA collected from the lower sides to that from the upper sides was about 1.4 between 5 and 10 minutes. This was adequately early to account for the beginning of curvature. The auxin asymmetry ratio rose to about 2.5 between 20 and 25 minutes, and to 3.5 during the main phase of curvature. This compares reasonably well with the roughly 3.9 ratio for elongation on the lower side to elongation on the upper side that is the basis for the curvature. These data extend evidence that the Went-Cholodny theory for the mediation of tropisms is valid for dicot stems. Also consistent with the theory, an auxin asymmetry ratio of 2.5 was observed when wrong-way gravitropic curvature developed following application of a high level of auxin. In addition to reversing the asymmetry of elongation, the large supplement of auxin resulted in lower net elongation. Previous data established that ethylene is not involved in this decrease of growth as a function of increasing level of auxin.

[Presurgical orthodontics for facial asymmetry].

PubMed

Labarrère, H

2003-03-01

As with the treatment of all facial deformities, orthodontic pre-surgical preparation for facial asymmetry should aim at correcting severe occlusal discrepancies not solely on the basis of a narrow occlusal analysis but also in a way that will not disturb the proposed surgical protocol. In addition, facial asymmetries require specific adjustments, difficult to derive and to apply because of their inherent atypical morphological orientation of both alveolar and basal bony support. Three treated cases illustrate different solutions to problems posed by pathological torque: this torque must be considered with respect to proposed surgical changes, within the framework of their limitations and their possible contra-indications.

Prefrontal brain asymmetry and aggression in imprisoned violent offenders.

PubMed

Keune, Philipp M; van der Heiden, Linda; Várkuti, Bálint; Konicar, Lilian; Veit, Ralf; Birbaumer, Niels

2012-05-02

Anterior brain asymmetry, assessed through the alpha and beta band in resting-state electroencephalogram (EEG) is associated with approach-related behavioral dispositions, particularly with aggression in the general population. To date, the association between frontal asymmetry and aggression has not been examined in highly aggressive groups. We examined the topographic characteristics of alpha and beta activity, the relation of both asymmetry metrics to trait aggression, and whether alpha asymmetry was extreme in anterior regions according to clinical standards in a group of imprisoned violent offenders. As expected, these individuals were characterized by stronger right than left-hemispheric alpha activity, which was putatively extreme in anterior regions in one third of the cases. We also report that in line with observations made in the general population, aggression was associated with stronger right-frontal alpha activity in these violent individuals. This suggests that frontal alpha asymmetry, as a correlate of trait aggression, might be utilizable as an outcome measure in studies which assess the effects of anti-aggressiveness training in violent offenders. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Frobenius-norm-based measures of quantum coherence and asymmetry

PubMed Central

Yao, Yao; Dong, G. H.; Xiao, Xing; Sun, C. P.

2016-01-01

We formulate the Frobenius-norm-based measures for quantum coherence and asymmetry respectively. In contrast to the resource theory of coherence and asymmetry, we construct a natural measure of quantum coherence inspired from optical coherence theory while the group theoretical approach is employed to quantify the asymmetry of quantum states. Besides their simple structures and explicit physical meanings, we observe that these quantities are intimately related to the purity (or linear entropy) of the corresponding quantum states. Remarkably, we demonstrate that the proposed coherence quantifier is not only a measure of mixedness, but also an intrinsic (basis-independent) quantification of quantum coherence contained in quantum states, which can also be viewed as a normalized version of Brukner-Zeilinger invariant information. In our context, the asymmetry of N-qubit quantum systems is considered under local independent and collective transformations. In- triguingly, it is illustrated that the collective effect has a significant impact on the asymmetry measure, and quantum correlation between subsystems plays a non-negligible role in this circumstance. PMID:27558009

Using ground reaction force to predict knee kinetic asymmetry following anterior cruciate ligament reconstruction.

PubMed

Dai, B; Butler, R J; Garrett, W E; Queen, R M

2014-12-01

Asymmetries in sagittal plane knee kinetics have been identified as a risk factor for anterior cruciate ligament (ACL) re-injury. Clinical tools are needed to identify the asymmetries. This study examined the relationships between knee kinetic asymmetries and ground reaction force (GRF) asymmetries during athletic tasks in adolescent patients following ACL reconstruction (ACL-R). Kinematic and GRF data were collected during a stop-jump task and a side-cutting task for 23 patients. Asymmetry indices between the surgical and non-surgical limbs were calculated for GRF and knee kinetic variables. For the stop-jump task, knee kinetics asymmetry indices were correlated with all GRF asymmetry indices (P < 0.05), except for loading rate. Vertical GRF impulse asymmetry index predicted peak knee moment, average knee moment, and knee work (R(2)  ≥ 0.78, P < 0.01) asymmetry indices. For the side-cutting tasks, knee kinetic asymmetry indices were correlated with the peak propulsion vertical GRF and vertical GRF impulse asymmetry indices (P < 0.05). Vertical GRF impulse asymmetry index predicted peak knee moment, average knee moment, and knee work (R(2)  ≥ 0.55, P < 0.01) asymmetry indices. The vertical GRF asymmetries may be a viable surrogate for knee kinetic asymmetries and therefore may assist in optimizing rehabilitation outcomes and minimizing re-injury rates. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

microRNA function in left-right neuronal asymmetry: perspectives from C. elegans.

PubMed

Alqadah, Amel; Hsieh, Yi-Wen; Chuang, Chiou-Fen

2013-09-23

Left-right asymmetry in anatomical structures and functions of the nervous system is present throughout the animal kingdom. For example, language centers are localized in the left side of the human brain, while spatial recognition functions are found in the right hemisphere in the majority of the population. Disruption of asymmetry in the nervous system is correlated with neurological disorders. Although anatomical and functional asymmetries are observed in mammalian nervous systems, it has been a challenge to identify the molecular basis of these asymmetries. C. elegans has emerged as a prime model organism to investigate molecular asymmetries in the nervous system, as it has been shown to display functional asymmetries clearly correlated to asymmetric distribution and regulation of biologically relevant molecules. Small non-coding RNAs have been recently implicated in various aspects of neural development. Here, we review cases in which microRNAs are crucial for establishing left-right asymmetries in the C. elegans nervous system. These studies may provide insight into how molecular and functional asymmetries are established in the human brain.

Left-right leaf asymmetry in decussate and distichous phyllotactic systems.

PubMed

Martinez, Ciera C; Chitwood, Daniel H; Smith, Richard S; Sinha, Neelima R

2016-12-19

Leaves in plants with spiral phyllotaxy exhibit directional asymmetries, such that all the leaves originating from a meristem of a particular chirality are similarly asymmetric relative to each other. Models of auxin flux capable of recapitulating spiral phyllotaxis predict handed auxin asymmetries in initiating leaf primordia with empirically verifiable effects on superficially bilaterally symmetric leaves. Here, we extend a similar analysis of leaf asymmetry to decussate and distichous phyllotaxy. We found that our simulation models of these two patterns predicted mirrored asymmetries in auxin distribution in leaf primordia pairs. To empirically verify the morphological consequences of asymmetric auxin distribution, we analysed the morphology of a tomato sister-of-pin-formed1a (sopin1a) mutant, entire-2, in which spiral phyllotaxy consistently transitions to a decussate state. Shifts in the displacement of leaflets on the left and right sides of entire-2 leaf pairs mirror each other, corroborating predicted model results. We then analyse the shape of more than 800 common ivy (Hedera helix) and more than 3000 grapevine (Vitis and Ampelopsis spp.) leaf pairs and find statistical enrichment of predicted mirrored asymmetries. Our results demonstrate that left-right auxin asymmetries in models of decussate and distichous phyllotaxy successfully predict mirrored asymmetric leaf morphologies in superficially symmetric leaves.This article is part of the themed issue 'Provocative questions in left-right asymmetry'. © 2016 The Author(s).

Magnetic fields and chiral asymmetry in the early hot universe

NASA Astrophysics Data System (ADS)

Sydorenko, Maksym; Tomalak, Oleksandr; Shtanov, Yuri

2016-10-01

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

Subtasks affecting step-length asymmetry in post-stroke hemiparetic walking.

PubMed

Kim, Woo-Sub

2016-10-01

This study was performed to investigate whether components from trunk progression (TP) and step length were related to step length asymmetry in walking in patients with hemiparesis. Gait analysis was performed for participants with hemiparesis and healthy controls. The distance between the pelvis and foot in the anterior-posterior axis was calculated at initial-contact. Step length was partitioned into anterior foot placement (AFP) and posterior foot placement (PFP). TP was partitioned into anterior trunk progression (ATP) and posterior trunk progression (PTP). The TP pattern and step length pattern were defined to represent intra-TP and intra-step spatial balance, respectively. Of 29 participants with hemiparesis, nine participants showed longer paretic step length, eight participants showed symmetric step length, and 12 participants showed shorter paretic step length. For the hemiparesis group, linear regression analysis showed that ATP asymmetry, AFP asymmetry, and TP patterns had significant predictability regarding step length asymmetry. Prolonged paretic ATP and shortened paretic AFP was the predominant pattern in the hemiparesis group, even in participants with symmetric step length. However, some participants showed same direction of ATP and AFP asymmetry. These findings indicate the following: (1) ATP asymmetries should be observed to determine individual characteristics of step length asymmetry, and (2) TP patterns can provide complementary information for non-paretic limb compensation. Copyright © 2016 Elsevier B.V. All rights reserved.

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

PubMed

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

2015-01-01

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

The validity of individual frontal alpha asymmetry EEG neurofeedback.

PubMed

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

2016-01-01

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

Asymmetry of magnetic motor evoked potentials recorded in calf muscles of the dominant and non-dominant lower extremity.

PubMed

Olex-Zarychta, Dorota; Koprowski, Robert; Sobota, Grzegorz; Wróbel, Zygmunt

2009-08-07

The aim of the study was to determine the applicability of magnetic stimulation and magnetic motor evoked potentials (MEPs) in motor asymmetry studies by obtaining quantitative and qualitative measures of efferent activity during low intensity magnetic stimulation of the dominant and non-dominant lower extremities. Magnetic stimulation of the tibial nerve in the popliteal fossa was performed in 10 healthy male right-handed and right-footed young adults. Responses were recorded from the lateral head of the gastrocnemius muscles of the right and left lower extremities. Response characteristics (duration, onset latency, amplitude) were analyzed in relation to the functional dominance of the limbs and in relation to the direction of the current in the magnetic coil by use of the Wilcoxon pair sequence test. The CCW direction of coil current was related to reduced amplitudes of recorded MEPs. Greater amplitudes of evoked potentials were recorded in the non-dominant extremity, both in the CW and CCW coil current directions, with the statistical significance of this effect (p=0.005). No differences in duration of response were found in the CW current direction, while in CCW the time of the left-side response was prolonged (p=0.01). In the non-dominant extremity longer onset latencies were recorded in both current directions, but only for the CW direction the side asymmetries showed a statistical significance of p=0.005. In the dominant extremity the stimulation correlated with stronger paresthesias, especially using the CCW direction of coil current. The results indicate that low intensity magnetic stimulation may be useful in quantitative and qualitative research into the motor asymmetry.

Automated measurement of vocal fold vibratory asymmetry from high-speed videoendoscopy recordings.

PubMed

Mehta, Daryush D; Deliyski, Dimitar D; Quatieri, Thomas F; Hillman, Robert E

2011-02-01

In prior work, a manually derived measure of vocal fold vibratory phase asymmetry correlated to varying degrees with visual judgments made from laryngeal high-speed videoendoscopy (HSV) recordings. This investigation extended this work by establishing an automated HSV-based framework to quantify 3 categories of vocal fold vibratory asymmetry. HSV-based analysis provided for cycle-to-cycle estimates of left-right phase asymmetry, left-right amplitude asymmetry, and axis shift during glottal closure for 52 speakers with no vocal pathology producing comfortable and pressed phonation. An initial cross-validation of the automated left-right phase asymmetry measure was performed by correlating the measure with other objective and subjective assessments of phase asymmetry. Vocal fold vibratory asymmetry was exhibited to a similar extent in both comfortable and pressed phonations. The automated measure of left-right phase asymmetry strongly correlated with manually derived measures and moderately correlated with visual-perceptual ratings. Correlations with the visual-perceptual ratings remained relatively consistent as the automated measure was derived from kymograms taken at different glottal locations. An automated HSV-based framework for the quantification of vocal fold vibratory asymmetry was developed and initially validated. This framework serves as a platform for investigating relationships between vocal fold tissue motion and acoustic measures of voice function.

Crossed asymmetry in Russell-Silver syndrome.

PubMed Central

Qazi, Q H; Kassner, E G; Ganapathy, C

1977-01-01

Since the initial report by Silver et al (1953), more than 50 examples of the Russell-Silver syndrome have been reported. Unilateral congenital asymmetry of the extremities has been considered one of the major features of this disorder (Silver, 1964). We recently observed a child with otherwise typical features of the Russell-Silver syndrome who had enlargement of the right hand and of the left lower extremity. We know of no other recorded example of crossed asymmetry in this clinical entity. Images PMID:839508

Symmetry and asymmetry in aesthetics and the arts

NASA Astrophysics Data System (ADS)

McManus, I. C.

2005-10-01

Symmetry and beauty are often claimed to be linked, particularly by mathematicians and scientists. However philosophers and art historians seem generally agreed that although symmetry is indeed attractive, there is also a somewhat sterile rigidity about it, which can make it less attractive than the more dynamic, less predictable beauty associated with asymmetry. Although a little asymmetry can be beautiful, an excess merely results in chaos. As Adorno suggested, asymmetry probably results most effectively in beauty when the underlying symmetry upon which it is built is still apparent. This paper examines the ways in which asymmetries, particularly left-right asymmetries, were used by painters in the Italian Renaissance. Polyptychs often show occasional asymmetries, which are more likely to involve the substitution of a left cheek for a right cheek, than vice-versa. A hypothesis is developed that the left and right cheeks have symbolic meanings, with the right cheek meaning "like self" and the left cheek meaning "unlike self". This principle is evaluated in pictures such as the Crucifixion, the Annunciation and, the Madonna and Child. The latter is particularly useful because the theological status of the Madonna changed during the Renaissance, and her left-right portrayal also changed at the same time in a comprehensible way. Some brief experimental tests of the hypothesis are also described. Finally the paper ends by considering why it is that the left rather than the right cheek is associated with "unlike self", and puts that result in the context of the universal "dual symbolic classification" of right and left, which was first described by the anthropologist Robert Hertz.

Phosphatidylserine-Targeted Nanotheranostics for Brain Tumor Imaging and Therapeutic Potential

PubMed Central

Wang, Lulu; Habib, Amyn A.; Mintz, Akiva; Li, King C.; Zhao, Dawen

2017-01-01

Phosphatidylserine (PS), the most abundant anionic phospholipid in cell membrane, is strictly confined to the inner leaflet in normal cells. However, this PS asymmetry is found disruptive in many tumor vascular endothelial cells. We discuss the underlying mechanisms for PS asymmetry maintenance in normal cells and its loss in tumor cells. The specificity of PS exposure in tumor vasculature but not normal blood vessels may establish it a useful biomarker for cancer molecular imaging. Indeed, utilizing PS-targeting antibodies, multiple imaging probes have been developed and multimodal imaging data have shown their high tumor-selective targeting in various cancers. There is a critical need for improved diagnosis and therapy for brain tumors. We have recently established PS-targeted nanoplatforms, aiming to enhance delivery of imaging contrast agents across the blood–brain barrier to facilitate imaging of brain tumors. Advantages of using the nanodelivery system, in particular, lipid-based nanocarriers, are discussed here. We also describe our recent research interest in developing PS-targeted nanotheranostics for potential image-guided drug delivery to treat brain tumors. PMID:28654387

Phosphatidylserine-Targeted Nanotheranostics for Brain Tumor Imaging and Therapeutic Potential.

PubMed

Wang, Lulu; Habib, Amyn A; Mintz, Akiva; Li, King C; Zhao, Dawen

2017-01-01

Phosphatidylserine (PS), the most abundant anionic phospholipid in cell membrane, is strictly confined to the inner leaflet in normal cells. However, this PS asymmetry is found disruptive in many tumor vascular endothelial cells. We discuss the underlying mechanisms for PS asymmetry maintenance in normal cells and its loss in tumor cells. The specificity of PS exposure in tumor vasculature but not normal blood vessels may establish it a useful biomarker for cancer molecular imaging. Indeed, utilizing PS-targeting antibodies, multiple imaging probes have been developed and multimodal imaging data have shown their high tumor-selective targeting in various cancers. There is a critical need for improved diagnosis and therapy for brain tumors. We have recently established PS-targeted nanoplatforms, aiming to enhance delivery of imaging contrast agents across the blood-brain barrier to facilitate imaging of brain tumors. Advantages of using the nanodelivery system, in particular, lipid-based nanocarriers, are discussed here. We also describe our recent research interest in developing PS-targeted nanotheranostics for potential image-guided drug delivery to treat brain tumors.

A method for determining poloidal rotation from poloidal asymmetry in toroidal rotation (invited)

DOE PAGES

Chrystal, Chrystal; Burrell, Keith H.; Grierson, Brian A.; ...

2014-08-08

A new diagnostic has been developed on DIII-D that determines the impurity poloidal rotation from the poloidal asymmetry in the toroidal angular rotation velocity. This asymmetry is measured with recently added tangential charge exchange viewchords on the high-field side of the tokamak midplane. Measurements are made on co- and counter-current neutral beams, allowing the charge exchange cross section effect to be measured and eliminating the need for atomic physics calculations. The diagnostic implementation on DIII-D restricts the measurement range to the core (r/a < 0.6) where, relative to measurements made with the vertical charge exchange system, the spatial resolution ismore » improved. Furthermore, significant physics results have been obtained with this new diagnostic; for example, poloidal rotation measurements that significantly exceed neoclassical predictions.« less

Baryogenesis and dark matter through a Higgs asymmetry.

PubMed

Servant, Géraldine; Tulin, Sean

2013-10-11

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

Perisylvian sulcal morphology and cerebral asymmetry patterns in adults who stutter.

PubMed

Cykowski, Matthew D; Kochunov, Peter V; Ingham, Roger J; Ingham, Janis C; Mangin, Jean-François; Rivière, Denis; Lancaster, Jack L; Fox, Peter T

2008-03-01

Previous investigations of cerebral anatomy in persistent developmental stutterers have reported bilateral anomalies in the perisylvian region and atypical patterns of cerebral asymmetry. In this study, perisylvian sulcal patterns were analyzed to compare subjects with persistent developmental stuttering (PDS) and an age-, hand-, and gender-matched control group. This analysis was accomplished using software designed for 3-dimensional sulcal identification and extraction. Patterns of cerebral asymmetry were also investigated with standard planimetric measurements. PDS subjects showed a small but significant increase in both the number of sulci connecting with the second segment of the right Sylvian fissure and in the number of suprasylvian gyral banks (of sulci) along this segment. No differences were seen in the left perisylvian region for either sulcal number or gyral bank number. Measurements of asymmetry revealed typical patterns of cerebral asymmetry in both groups with no significant differences in frontal and occipital width asymmetry, frontal and occipital pole asymmetry, or planum temporale and Sylvian fissure asymmetries. The subtle difference in cortical folding of the right perisylvian region observed in PDS subjects may correlate with functional imaging studies that have reported increased right-hemisphere activity during stuttered speech.

Decision making in noisy bistable systems with time-dependent asymmetry

NASA Astrophysics Data System (ADS)

Nené, Nuno R.; Zaikin, Alexey

2013-01-01

Our work draws special attention to the importance of the effects of time-dependent parameters on decision making in bistable systems. Here, we extend previous studies of the mechanism known as speed-dependent cellular decision making in genetic circuits by performing an analytical treatment of the canonical supercritical pitchfork bifurcation problem with an additional time-dependent asymmetry and control parameter. This model has an analogous behavior to the genetic switch. In the presence of transient asymmetries and fluctuations, slow passage through the critical region in both systems increases substantially the probability of specific decision outcomes. We also study the relevance for attractor selection of reaching maximum values for the external asymmetry before and after the critical region. Overall, maximum asymmetries should be reached at an instant where the position of the critical point allows for compensation of the detrimental effects of noise in retaining memory of the transient asymmetries.

Measurement of the beam asymmetry Σ for π0 and η photoproduction on the proton at Eγ=9 GeV

NASA Astrophysics Data System (ADS)

Al Ghoul, H.; Anassontzis, E. G.; Austregesilo, A.; Barbosa, F.; Barnes, A.; Beattie, T. D.; Bennett, D. W.; Berdnikov, V. V.; Black, T.; Boeglin, W.; Briscoe, W. J.; Brooks, W. K.; Cannon, B. E.; Chernyshov, O.; Chudakov, E.; Crede, V.; Dalton, M. M.; Deur, A.; Dobbs, S.; Dolgolenko, A.; Dugger, M.; Dzhygadlo, R.; Egiyan, H.; Eugenio, P.; Fanelli, C.; Foda, A. M.; Frye, J.; Furletov, S.; Gan, L.; Gasparian, A.; Gerasimov, A.; Gevorgyan, N.; Goetzen, K.; Goryachev, V. S.; Guo, L.; Hakobyan, H.; Hardin, J.; Henderson, A.; Huber, G. M.; Ireland, D. G.; Ito, M. M.; Jarvis, N. S.; Jones, R. T.; Kakoyan, V.; Kamel, M.; Klein, F. J.; Kliemt, R.; Kourkoumeli, C.; Kuleshov, S.; Kuznetsov, I.; Lara, M.; Larin, I.; Lawrence, D.; Levine, W. I.; Livingston, K.; Lolos, G. J.; Lyubovitskij, V.; Mack, D.; Mattione, P. T.; Matveev, V.; McCaughan, M.; McCracken, M.; McGinley, W.; McIntyre, J.; Mendez, R.; Meyer, C. A.; Miskimen, R.; Mitchell, R. E.; Mokaya, F.; Moriya, K.; Nerling, F.; Nigmatkulov, G.; Ochoa, N.; Ostrovidov, A. I.; Papandreou, Z.; Patsyuk, M.; Pedroni, R.; Pennington, M. R.; Pentchev, L.; Peters, K. J.; Pooser, E.; Pratt, B.; Qiang, Y.; Reinhold, J.; Ritchie, B. G.; Robison, L.; Romanov, D.; Salgado, C.; Schumacher, R. A.; Schwarz, C.; Schwiening, J.; Semenov, A. Yu.; Semenova, I. A.; Seth, K. K.; Shepherd, M. R.; Smith, E. S.; Sober, D. I.; Somov, A.; Somov, S.; Soto, O.; Sparks, N.; Staib, M. J.; Stevens, J. R.; Strakovsky, I. I.; Subedi, A.; Tarasov, V.; Taylor, S.; Teymurazyan, A.; Tolstukhin, I.; Tomaradze, A.; Toro, A.; Tsaris, A.; Vasileiadis, G.; Vega, I.; Walford, N. K.; Werthmüller, D.; Whitlatch, T.; Williams, M.; Wolin, E.; Xiao, T.; Zarling, J.; Zhang, Z.; Zihlmann, B.; Mathieu, V.; Nys, J.; GlueX Collaboration

2017-04-01

We report measurements of the photon beam asymmetry Σ for the reactions γ ⃗p →p π0 and γ ⃗p →p η from the GlueX experiment using a 9 GeV linearly polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous π0 measurements and are the first η measurements in this energy regime. The results are compared with theoretical predictions based on t -channel, quasiparticle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models.

Hemispheric Asymmetry in the Efficiency of Attentional Networks

ERIC Educational Resources Information Center

Asanowicz, Dariusz; Marzecova, Anna; Jaskowski, Piotr; Wolski, Piotr

2012-01-01

Despite the fact that hemispheric asymmetry of attention has been widely studied, a clear picture of this complex phenomenon is still lacking. The aim of the present study was to provide an efficient and reliable measurement of potential hemispheric asymmetries of three attentional networks, i.e. alerting, orienting and executive attention.…

Magnetic fields and chiral asymmetry in the early hot universe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sydorenko, Maksym; Shtanov, Yuri; Tomalak, Oleksandr, E-mail: maxsydorenko@gmail.com, E-mail: tomalak@uni-mainz.de, E-mail: shtanov@bitp.kiev.ua

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

First Observation of the Parity Violating Asymmetry in Moller Scattering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Younus, Imran; /Syracuse U.

This thesis reports on the E158 experiment at Stanford Linear Accelerator Center (SLAC), which has made the first observation of the parity non-conserving asymmetry in Moller scattering. Longitudinally polarized 48 GeV electrons are scattered off unpolarized (atomic) electrons in a liquid hydrogen target with an average Q{sup 2} of 0.027 GeV{sup 2}. The asymmetry in this process is proportional to (1/4 - sin{sup 2}{theta}{sub W}), where sin{sup 2} {theta}{sub W} gives the weak mixing angle. The thesis describes the experiment in detail, with a particular focus on the design and construction of the electromagnetic calorimeter. This calorimeter was the primarymore » detector in the experiment used to measure the flux of the scattered Moller electrons and eP electrons. It employed the quartz fiber calorimetry technique, and was built at Syracuse University. The preliminary results from the first experimental data taken in spring 2002 give A{sub PV} = -151.9 {+-} 29.0(stat) {+-} 32.5(syst) parts per billion. This in turn gives sin{sup 2} {theta}{sub W} = 0.2371 {+-} 0.0025 {+-} 0.0027, which is consistent with the Standard Model prediction (0.2386 {+-} 0.0006).« less

Significance of postshunt ventricular asymmetries.

PubMed

Linder, M; Diehl, J T; Sklar, F H

1981-08-01

Ventricular asymmetries after shunt surgery were studied. Right and left ventricular areas from pre-and postoperative computerized tomography scans were measured with a computer digitizing technique, and the respective areas were expressed as a ratio. Measurements were made from the scans of 15 hydrocephalic children selected at random. Ages at surgery ranged from 1 to 101 weeks. The results indicate a significantly greater decrease in ventricular size on the side of the ventricular shunt catheter. Multiple regression analysis showed no relationship between the magnitude of change in ventricular size and either the patients' age orn the time intervals between surgery and follow-up scans. Possible mechanisms for these postshunt ventricular asymmetries are discussed.

Ocular adnexal asymmetry in models: a magazine photograph analysis.

PubMed

Ing, Edsel; Safarpour, Azien; Ing, Tom; Ing, Sabrina

2006-04-01

Symmetry of facial features often correlates with a perception of physical attractiveness, and ophthalmologists are sometimes consulted by patients for eyelid, eyebrow, or orbital asymmetry. Our objective was to determine the prevalence of ocular adnexal asymmetry among people generally regarded as attractive. The mean width of the horizontal palpebral fissure (MHPF) for both men and women was determined in 40 adult volunteers. Then unobscured, head-on photographs of models looking in the primary position were digitally scanned from popular magazines. Eyelid height, eyelid folds, eyebrow height, medial canthus to midline distance, pupil to midline distance, and orbital dystopia measurements were made. After the measurements from the models were scaled to size by factoring with the MHPF obtained from the volunteers, the results were analyzed by paired samples t test for right-left asymmetry of the ocular adnexal measurements. We also examined for antimongoloid slant in the models. The MHPF of the volunteers was 27+/-1.3 mm for women and 29.6+/-2.0 mm for men. Of 102 magazine photographs analyzed, 55 were women and 47 men. As a group, the models showed a statistically significant asymmetry (p<0.05) in the horizontal fissure width, upper central lid fold, upper temporal lid fold, central eyebrow height, temporal eyebrow height, medial canthal to midline distance, pupil to midline distance, and orbital dystopia. The female models had more eyebrow asymmetry. The male models had more asymmetry at the horizontal fissure and with orbital dystopia. Two male models also had a unilateral antimongoloid slant. Small to moderate amounts of eyelid, eyebrow, and orbital asymmetry were observed in faces generally perceived as attractive. This fact should be considered during preoperative discussions with patients considering oculoplastic surgery.

The intricate Galaxy disk: velocity asymmetries in Gaia-TGAS

NASA Astrophysics Data System (ADS)

Antoja, T.; de Bruijne, J.; Figueras, F.; Mor, R.; Prusti, T.; Roca-Fàbrega, S.

2017-06-01

We use Gaia-TGAS data to compare the transverse velocities in Galactic longitude (coming from proper motions and parallaxes) in the Milky Way disk for negative and positive longitudes as a function of distance. The transverse velocities are strongly asymmetric and deviate significantly from the expectations for an axisymmetric galaxy. The value and sign of the asymmetry changes at spatial scales of several tens of degrees in Galactic longitude and about 0.5 kpc in distance. The asymmetry is statistically significant at 95% confidence level for 57% of the region probed, which extends up to 1.2 kpc. A percentage of 24% of the region shows absolute differences at this confidence level larger than 5 km s-1 and 7% larger than 10 km s-1. The asymmetry pattern shows mild variations in the vertical direction and with stellar type. A first qualitative comparison with spiral arm models indicates that the arms are probably not the main source of the asymmetry. We briefly discuss alternative origins. This is the first time that global all-sky asymmetries are detected in the Milky Way kinematics beyond the local neighbourhood and with a purely astrometric sample.

Scale-dependent CMB power asymmetry from primordial speed of sound and a generalized δ N formalism

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Dong-Gang; Cai, Yi-Fu; Zhao, Wen

2016-02-01

We explore a plausible mechanism that the hemispherical power asymmetry in the CMB is produced by the spatial variation of the primordial sound speed parameter. We suggest that in a generalized approach of the δ N formalism the local e-folding number may depend on some other primordial parameters besides the initial values of inflaton. Here the δ N formalism is extended by considering the effects of a spatially varying sound speed parameter caused by a super-Hubble perturbation of a light field. Using this generalized δ N formalism, we systematically calculate the asymmetric primordial spectrum in the model of multi-speed inflation by taking intomore » account the constraints of primordial non-Gaussianities. We further discuss specific model constraints, and the corresponding asymmetry amplitudes are found to be scale-dependent, which can accommodate current observations of the power asymmetry at different length scales.« less

Measurement of the proton $$A_1$$ and $$A_2$$ spin asymmetries. Probing Color Forces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armstrong, Whitney

The Spin Asymmetries of the Nucleon Experiment (SANE) measured the proton spin structure functionmore » $$g_2$$ in a range of Bjorken x, 0.3 < x < 0.8, where extraction of the twist-3 matrix element $$d_2^p$$ (an integral of $$g_2$$ weighted by $x^2$) is most sensitive. The data was taken from $Q^2$ equal to 2.5 $GeV^2$ up to 6.5 $GeV^2$. In this polarized electron scattering off a polarized hydrogen target experiment, two double spin asymmetries, A∥ and A⊥ were measured using the BETA (Big Electron Telescope Array) Detector. BETA consisted of a scintillator hodoscope, gas Cerenkov counter, lucite hodoscope and a large lead glass electromagnetic calorimeter. With a unique open geometry, a threshold gas Cerenkov detector allowed BETA to cleanly identify electrons for this inclusive experiment. A measurement of $$d_2^p$$ is compared to lattice QCD calculations.« less

Co-clustering directed graphs to discover asymmetries and directional communities

PubMed Central

Rohe, Karl; Qin, Tai; Yu, Bin

2016-01-01

In directed graphs, relationships are asymmetric and these asymmetries contain essential structural information about the graph. Directed relationships lead to a new type of clustering that is not feasible in undirected graphs. We propose a spectral co-clustering algorithm called di-sim for asymmetry discovery and directional clustering. A Stochastic co-Blockmodel is introduced to show favorable properties of di-sim. To account for the sparse and highly heterogeneous nature of directed networks, di-sim uses the regularized graph Laplacian and projects the rows of the eigenvector matrix onto the sphere. A nodewise asymmetry score and di-sim are used to analyze the clustering asymmetries in the networks of Enron emails, political blogs, and the Caenorhabditis elegans chemical connectome. In each example, a subset of nodes have clustering asymmetries; these nodes send edges to one cluster, but receive edges from another cluster. Such nodes yield insightful information (e.g., communication bottlenecks) about directed networks, but are missed if the analysis ignores edge direction. PMID:27791058

Co-clustering directed graphs to discover asymmetries and directional communities.

PubMed

Rohe, Karl; Qin, Tai; Yu, Bin

2016-10-21

In directed graphs, relationships are asymmetric and these asymmetries contain essential structural information about the graph. Directed relationships lead to a new type of clustering that is not feasible in undirected graphs. We propose a spectral co-clustering algorithm called di-sim for asymmetry discovery and directional clustering. A Stochastic co-Blockmodel is introduced to show favorable properties of di-sim To account for the sparse and highly heterogeneous nature of directed networks, di-sim uses the regularized graph Laplacian and projects the rows of the eigenvector matrix onto the sphere. A nodewise asymmetry score and di-sim are used to analyze the clustering asymmetries in the networks of Enron emails, political blogs, and the Caenorhabditis elegans chemical connectome. In each example, a subset of nodes have clustering asymmetries; these nodes send edges to one cluster, but receive edges from another cluster. Such nodes yield insightful information (e.g., communication bottlenecks) about directed networks, but are missed if the analysis ignores edge direction.

Communication Apprehension and Resting Alpha Range Asymmetry in the Anterior Cortex

ERIC Educational Resources Information Center

Beatty, Michael J.; Heisel, Alan D.; Lewis, Robert J.; Pence, Michelle E.; Reinhart, Amber; Tian, Yan

2011-01-01

In this study, we examined the relationship between trait-like communication apprehension (CA) and resting alpha range asymmetry in the anterior cortex (AC). Although theory and research in cognitive neuroscience suggest that asymmetry in the AC constitutes a relatively stable, inborn, substrate of emotion, some studies indicate that asymmetry can…

Challenging Postural Tasks Increase Asymmetry in Patients with Parkinson’s Disease

PubMed Central

Beretta, Victor Spiandor; Gobbi, Lilian Teresa Bucken; Lirani-Silva, Ellen; Simieli, Lucas; Orcioli-Silva, Diego; Barbieri, Fabio Augusto

2015-01-01

The unilateral predominance of Parkinson’s disease (PD) symptoms suggests that balance control could be asymmetrical during static tasks. Although studies have shown that balance control asymmetries exist in patients with PD, these analyses were performed using only simple bipedal standing tasks. Challenging postural tasks, such as unipedal or tandem standing, could exacerbate balance control asymmetries. To address this, we studied the impact of challenging standing tasks on postural control asymmetry in patients with PD. Twenty patients with PD and twenty neurologically healthy individuals (control group) participated in this study. Participants performed three 30s trials for each postural task: bipedal, tandem adapted and unipedal standing. The center of pressure parameter was calculated for both limbs in each of these conditions, and the asymmetry between limbs was assessed using the symmetric index. A significant effect of condition was observed, with unipedal standing and tandem standing showing greater asymmetry than bipedal standing for the mediolateral root mean square (RMS) and area of sway parameters, respectively. In addition, a group*condition interaction indicated that, only for patients with PD, the unipedal condition showed greater asymmetry in the mediolateral RMS and area of sway than the bipedal condition and the tandem condition showed greater asymmetry in the area of sway than the bipedal condition. Patients with PD exhibited greater asymmetry while performing tasks requiring postural control when compared to neurologically healthy individuals, especially for challenging tasks such as tandem and unipedal standing. PMID:26367032

Frontal alpha asymmetry and sexually motivated states.

PubMed

Prause, Nicole; Staley, Cameron; Roberts, Verena

2014-03-01

Anterior alpha asymmetry of electroencephalographic (EEG) signals has been suggested to index state approach (or avoidance) motivation. This model has not yet been extended to high approach-motivation sexual stimuli, which may represent an important model of reward system function. Sixty-five participants viewed a neutral and a sexually motivating film while their EEG was recorded, and reported their sexual feelings after each film. Greater alpha power in the left hemisphere during sexually motivated states was evident. A positive relationship between self-reported mental sexual arousal and alpha asymmetry was identified, where coherence between these indicators was higher in women. Notably, coherence was stronger when mental versus physical sexual arousal was rated. Alpha asymmetry appears to offer a new method for further examining this novel coherence pattern across men and women. Copyright © 2014 Society for Psychophysiological Research.

Search asymmetries: parallel processing of uncertain sensory information.

PubMed

Vincent, Benjamin T

2011-08-01

What is the mechanism underlying search phenomena such as search asymmetry? Two-stage models such as Feature Integration Theory and Guided Search propose parallel pre-attentive processing followed by serial post-attentive processing. They claim search asymmetry effects are indicative of finding pairs of features, one processed in parallel, the other in serial. An alternative proposal is that a 1-stage parallel process is responsible, and search asymmetries occur when one stimulus has greater internal uncertainty associated with it than another. While the latter account is simpler, only a few studies have set out to empirically test its quantitative predictions, and many researchers still subscribe to the 2-stage account. This paper examines three separate parallel models (Bayesian optimal observer, max rule, and a heuristic decision rule). All three parallel models can account for search asymmetry effects and I conclude that either people can optimally utilise the uncertain sensory data available to them, or are able to select heuristic decision rules which approximate optimal performance. Copyright © 2011 Elsevier Ltd. All rights reserved.

Critical asymmetry in renormalization group theory for fluids.

PubMed

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

2013-06-21

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

Creation and Evolution of Particle Number Asymmetry in an Expanding Universe

NASA Astrophysics Data System (ADS)

Morozumi, T.; Nagao, K. I.; Adam, A. S.; Takata, H.

2017-03-01

We introduce a model which may generate particle number asymmetry in an expanding Universe. The model includes charge parity (CP) violating and particle number violating interactions. The model consists of a real scalar field and a complex scalar field. Starting with an initial condition specified by a density matrix, we show how the asymmetry is created through the interaction and how it evolves at later time. We compute the asymmetry using non-equilibrium quantum field theory and as a first test of the model, we study how the asymmetry evolves in the flat limit.

Baryon asymmetry from primordial black holes

NASA Astrophysics Data System (ADS)

Hamada, Yuta; Iso, Satoshi

2017-03-01

We propose a new scenario of the baryogenesis from primordial black holes (PBH). Assuming the presence of microscopic baryon (or lepton) number violation, and the presence of an effective CP-violating operator such as ∂αF (R…)Jα , where F (R…) is a scalar function of the Riemann tensor and Jα is a baryonic (leptonic) current, the time evolution of an evaporating black hole generates baryonic (leptonic) chemical potential at the horizon; consequently PBH emanates asymmetric Hawking radiation between baryons (leptons) and antibaryons (leptons). Though the operator is higher-dimensional and largely suppressed by a high mass scale M* , we show that a sufficient amount of asymmetry can be generated for a wide range of parameters of the PBH mass MPBH , its abundance ΩPBH , and the scale M*.

Line asymmetry in the Seyfert Galaxy NGC 3783

NASA Technical Reports Server (NTRS)

Ramirez, J. M.; Bautista, Manuel; Kallman, Timothy

2005-01-01

We have reanalyzed the 900 ks Chandra X-ray spectrum of NGC 3783, finding evidence on the asymmetry of the spectral absorption lines. The lines are fitted with a parametric expression that results from an analytical treatment of radiatively driven winds. The line asymmetry distribution derived from the spectrum is consistent with a non-spherical outflow with a finite optical depth. Within this scenario, our model explains the observed correlations between the line velocity shifts and the ionization parameter and between the line velocity shift and the line asymmetry. The present results may provide a framework for detailed testing of models for the dynamic and physical properties of warm absorber in Seyfert galaxies.

Yield Asymmetry Design of Magnesium Alloys by Integrated Computational Materials Engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Dongsheng; Joshi, Vineet V.; Lavender, Curt A.

2013-11-01

Deformation asymmetry of magnesium alloys is an important factor on machine design in automobile industry. Represented by the ratio of compressive yield stress (CYS) against tensile yield stress (TYS), deformation asymmetry is strongly related to microstructure, characterized by texture and grain size. Modified intermediate phi-model, a polycrystalline viscoplasticity model, is used to predict the deformation behavior of magnesium alloys with different grain sizes. Validated with experimental results, integrated computational materials engineering is applied to find out the route in achieving desired asymmetry by thermomechanical processing. In some texture, for example, rolled texture, CYS/TYS is smaller than 1 under different loadingmore » directions. In some texture, for example, extruded texture, asymmetry is large along normal direction. Starting from rolled texture, the asymmetry will increased to close to 1 along rolling direction after compressed to a strain of 0.2. Our model shows that grain refinement increases CYS/TYS. Besides texture control, grain refinement can also optimize the yield asymmetry. After the grain size decreased to a critical value, CYS/TYS reaches to 1 since CYS increases much faster than TYS. By tailoring the microstructure using texture control and grain refinement, it is achievable to optimize yield asymmetry in wrought magnesium alloys.« less

The effects of return current and target charging in short pulse high intensity laser interactions

NASA Astrophysics Data System (ADS)

Beg, Farhat

2003-10-01

Since the introduction of the technique of chirped pulse amplification (CPA), peak laser intensities have increased dramatically. It is now possible to perform laser-plasma interaction experiments at intensities approaching 1021 Wcm-2. The electrons in the field of such lasers are highly relativistic (gamma 31) and the temperature of the hot electron distribution produced in a plasma at such extreme intensities can exceed 10 MeV. Since the resulting beam current exceeds the Alfvén limit, a neutralizing return current of cold plasma electrons moving in the opposite direction is produced. Another source of return current is that due to the escape of very energetic electrons from the target, which then creates a large electrostatic potential due to charge separation. These return currents can cause significant ohmic heating. We present results from experiments performed at Rutherford Appleton Laboratory using the VULCAN laser facility (I> 5 x1019 Wcm-2). Single wire targets were used and in some shots a secondary wire or foil was placed near the target. Three main observations were made: (i) generation of a Z-pinch in the wire due to the return current, (ii) optical transition radiation at 2w and (iii) proton emission from both the primary wire target and the secondary wire or foil. The Z-pinch was observed to be m=0 unstable. The current was estimated to be about 0.8 MA using simple energy balance considerations. Intense second harmonic emission due to coherent optical transition radiation from both the primary target and secondary objects was observed and is likely due to electron bunches accelerated by the ponderomotive jxB force of the laser. The proton emission from the secondary wire or foil was likely due to field emission of electrons from the these objects in response to the large potential produced from charging of the primary target. Results of simulations to model these interactions will also be presented.

Effects of Convective Asymmetries on Hurricane Intensity: A Numerical Study

NASA Technical Reports Server (NTRS)

Wu, Liguang; Braun, Scott A.

2003-01-01

The influence of the uniform large-scale flow, beta effect, and vertical shear of the environmental flow on hurricane intensity is investigated in the context of the induced convective or potential vorticity asymmetries with a hydrostatic primitive equation hurricane model. In agreement with the previous studies, imposing of one of these environmental effects can substantially weaken the simulated tropical cyclones. In response t o the environmental influence, significant asymmetries develop with a structure similar to the spiral bands in real hurricanes, which are dominated by wavenumber-one components. The tendencies of the mean radial, azimuthal winds and temperature associated with the environment-induced convective asymmetries are evaluated respectively. The resulting asymmetries can effectively reduce hurricane intensity by directly producing the negative tendency of the mean tangential wind in the vicinity of the radius of maximum wind, and by weakening the mean radial circulation. The reduction effects are closely associated with the spiral structure of the induced asymmetries. The time lag observed between the imposition of the environmental influence and the resulting rise in the minimum central pressure is the time required for developing the spiral structure. This study also confirms the axisymmetrization process associated with the induced wavenumber-one components of potential vorticity asymmetries, but it exists only within the radius of maximum wind.

Measurement of the forward-backward asymmetry of $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production in $$p \\bar{p}$$ collisions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abazov, Victor Mukhamedovich

Here, we studymore » $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production asymmetries in $$p \\bar{p} \\rightarrow \\Lambda (\\bar{\\Lambda}) X$$, $$p \\bar{p} \\rightarrow J/\\psi \\Lambda (\\bar{\\Lambda}) X$$, and $$p \\bar{p} \\rightarrow \\mu^\\pm \\Lambda (\\bar{\\Lambda}) X$$ events recorded by the D0 detector at the Fermilab Tevatron collider at $$\\sqrt{s} = 1.96$$ TeV. We find an excess of $$\\Lambda$$'s ($$\\bar{\\Lambda}$$'s) produced in the proton (antiproton) direction. This forward-backward asymmetry is measured as a function of rapidity. We confirm that the $$\\bar{\\Lambda}/\\Lambda$$ production ratio, measured by several experiments with various targets and a wide range of energies, is a universal function of "rapidity loss", i.e., the rapidity difference of the beam proton and the lambda.« less

Measurement of the forward-backward asymmetry of $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production in $$p \\bar{p}$$ collisions

DOE PAGES

Abazov, Victor Mukhamedovich

2016-02-09

Here, we studymore » $$\\Lambda$$ and $$\\bar{\\Lambda}$$ production asymmetries in $$p \\bar{p} \\rightarrow \\Lambda (\\bar{\\Lambda}) X$$, $$p \\bar{p} \\rightarrow J/\\psi \\Lambda (\\bar{\\Lambda}) X$$, and $$p \\bar{p} \\rightarrow \\mu^\\pm \\Lambda (\\bar{\\Lambda}) X$$ events recorded by the D0 detector at the Fermilab Tevatron collider at $$\\sqrt{s} = 1.96$$ TeV. We find an excess of $$\\Lambda$$'s ($$\\bar{\\Lambda}$$'s) produced in the proton (antiproton) direction. This forward-backward asymmetry is measured as a function of rapidity. We confirm that the $$\\bar{\\Lambda}/\\Lambda$$ production ratio, measured by several experiments with various targets and a wide range of energies, is a universal function of "rapidity loss", i.e., the rapidity difference of the beam proton and the lambda.« less

Search asymmetry: a diagnostic for preattentive processing of separable features.

PubMed

Treisman, A; Souther, J

1985-09-01

The search rate for a target among distractors may vary dramatically depending on which stimulus plays the role of target and which that of distractors. For example, the time required to find a circle distinguished by an intersecting line is independent of the number of regular circles in the display, whereas the time to find a regular circle among circles with lines increases linearly with the number of distractors. The pattern of performance suggests parallel processing when the target has a unique distinguishing feature and serial self-terminating search when the target is distinguished only by the absence of a feature that is present in all the distractors. The results are consistent with feature-integration theory (Treisman & Gelade, 1980), which predicts that a single feature should be detected by the mere presence of activity in the relevant feature map, whereas tasks that require subjects to locate multiple instances of a feature demand focused attention. Search asymmetries may therefore offer a new diagnostic to identify the primitive features of early vision. Several candidate features are examined in this article: Colors, line ends or terminators, and closure (in the sense of a partly or wholly enclosed area) appear to be functional features; connectedness, intactness (absence of an intersecting line), and acute angles do not.

A study of the geomagnetic indices asymmetry based on the interplanetary magnetic field polarities

NASA Astrophysics Data System (ADS)

El-Borie, M. A.; El-Taher, A. M.; Aly, N. E.; Bishara, A. A.

2018-05-01

Data of geomagnetic indices ( aa, Kp, Ap, and Dst) recorded near 1 AU over the period 1967-2016, have been studied based on the asymmetry between the interplanetary magnetic field (IMF) directions above and below of the heliospheric current sheet (HCS). Our results led to the following conclusions: (i) Throughout the considered period, 31 random years (62%) showed apparent asymmetries between Toward (T) and Away (A) polarity days and 19 years (38%) exhibited nearly a symmetrical behavior. The days of A polarity predominated over the T polarity days by 4.3% during the positive magnetic polarity epoch (1991-1999). While the days of T polarity exceeded the days of A polarity by 5.8% during the negative magnetic polarity epoch (2001-2012). (ii) Considerable yearly North-South (N-S) asymmetries of geomagnetic indices observed throughout the considered period. (iii) The largest toward dominant peaks for aa and Ap indices occurred in 1995 near to minimum of solar activity. Moreover, the most substantial away dominant peaks for aa and Ap indices occurred in 2003 (during the descending phase of the solar cycle 23) and in 1991 (near the maximum of solar activity cycle) respectively. (iv) The N-S asymmetry of Kp index indicated a most significant away dominant peak occurred in 2003. (v) Four of the away dominant peaks of Dst index occurred at the maxima of solar activity in the years 1980, 1990, 2000, and 2013. The largest toward dominant peak occurred in 1991 (at the reversal of IMF polarity). (vi) The geomagnetic indices ( aa, Ap, and Kp) all have northern dominance during positive magnetic polarity epoch (1971-1979), while the asymmetries shifts to the southern solar hemisphere during negative magnetic polarity epoch (2001-2012).

Substrate Stiffness Regulates the Development of Left-Right Asymmetry in Cell Orientation.

PubMed

Bao, Yuanye; Huang, Yaozhun; Lam, Miu Ling; Xu, Ting; Zhu, Ninghao; Guo, Zhaobin; Cui, Xin; Lam, Raymond H W; Chen, Ting-Hsuan

2016-07-20

Left-right (LR) asymmetry of tissue/organ structure is a morphological feature essential for many tissue functions. The ability to incorporate the LR formation in constructing tissue/organ replacement is important for recapturing the inherent tissue structure and functions. However, how LR asymmetry is formed remains largely underdetermined, which creates significant hurdles to reproduce and regulate the formation of LR asymmetry in an engineering context. Here, we report substrate rigidity functioning as an effective switch that turns on the development of LR asymmetry. Using micropatterned cell-adherent stripes on rigid substrates, we found that cells collectively oriented at a LR-biased angle relative to the stripe boundary. This LR asymmetry was initiated by a LR-biased migration of cells at stripe boundary, which later generated a velocity gradient propagating from stripe boundary to the center. After a series of cell translocations and rotations, ultimately, an LR-biased cell orientation within the micropatterned stripe was formed. Importantly, this initiation and propagation of LR asymmetry was observed only on rigid but not on soft substrates, suggesting that the LR asymmetry was regulated by rigid substrate probably through the organization of actin cytoskeleton. Together, we demonstrated substrate rigidity as a determinant factor that mediates the self-organizing LR asymmetry being unfolded from single cells to multicellular organization. More broadly, we anticipate that our findings would pave the way for rebuilding artificial tissue constructs with inherent LR asymmetry in the future.

Mandibular asymmetry and the fourth dimension.

PubMed

Kaban, Leonard B

2009-03-01

This paper represents more than 30 years of discussion and collaboration with Drs Joseph Murray and John Mulliken in an attempt to understand growth patterns over time (ie, fourth dimension) in patients with hemifacial microsomia (HFM). This is essential for the development of rational treatment protocols for children and adults with jaw asymmetry. Traditionally, HFM was thought of as a unilateral deformity, but it was recognized that 20% to 30% of patients had bilateral abnormalities. However, early descriptions of skeletal correction addressed almost exclusively lengthening of the short (affected) side of the face. Based on longitudinal clinical observations of unoperated HFM patients, we hypothesized that abnormal mandibular growth is the earliest skeletal manifestation and that restricted growth of the mandible plays a pivotal role in progressive distortion of both the ipsilateral and contralateral facial skeleton. This hypothesis explains the progressive nature of the asymmetry in patients with HFM and provides the rationale for surgical lengthening of the mandible in children to prevent end-stage deformity. During the past 30 years, we have learned that this phenomenon of progressive distortion of the adjacent and contralateral facial skeleton occurs with other asymmetric mandibular undergrowth (tumor resection, radiation therapy, or posttraumatic defects) and overgrowth (mandibular condylar hyperplasia) conditions. In this paper, I describe the progression of deformity with time in patients with mandibular asymmetry as a result of undergrowth and overgrowth. Understanding these concepts is critical for the development of rational treatment protocols for adults with end-stage asymmetry and for children to minimize secondary deformity.

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

NASA Astrophysics Data System (ADS)

Bravi, Raffaella; Benítez, Hugo A.

2013-10-01

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

Mapping cortical brain asymmetry in 17,141 healthy individuals worldwide via the ENIGMA Consortium.

PubMed

Kong, Xiang-Zhen; Mathias, Samuel R; Guadalupe, Tulio; Glahn, David C; Franke, Barbara; Crivello, Fabrice; Tzourio-Mazoyer, Nathalie; Fisher, Simon E; Thompson, Paul M; Francks, Clyde

2018-05-29

Hemispheric asymmetry is a cardinal feature of human brain organization. Altered brain asymmetry has also been linked to some cognitive and neuropsychiatric disorders. Here, the ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) Consortium presents the largest-ever analysis of cerebral cortical asymmetry and its variability across individuals. Cortical thickness and surface area were assessed in MRI scans of 17,141 healthy individuals from 99 datasets worldwide. Results revealed widespread asymmetries at both hemispheric and regional levels, with a generally thicker cortex but smaller surface area in the left hemisphere relative to the right. Regionally, asymmetries of cortical thickness and/or surface area were found in the inferior frontal gyrus, transverse temporal gyrus, parahippocampal gyrus, and entorhinal cortex. These regions are involved in lateralized functions, including language and visuospatial processing. In addition to population-level asymmetries, variability in brain asymmetry was related to sex, age, and intracranial volume. Interestingly, we did not find significant associations between asymmetries and handedness. Finally, with two independent pedigree datasets ( n = 1,443 and 1,113, respectively), we found several asymmetries showing significant, replicable heritability. The structural asymmetries identified and their variabilities and heritability provide a reference resource for future studies on the genetic basis of brain asymmetry and altered laterality in cognitive, neurological, and psychiatric disorders.

Current and Future Trials of Targeted Therapies in Cutaneous Melanoma

PubMed Central

Madhunapantula, SubbaRao V.; Robertson, Gavin P.; Drabick, Joseph J.

2013-01-01

In order to effectively treat melanoma, targeted inhibition of key mechanistic events regulating melanoma development such as cell proliferation, survival, angiogenesis and invasion or metastasis needs to be accomplished. The Mitogen Activated Protein Kinase (MAPK) pathway has been identified as a key player in melanoma development making this cascade an important therapeutic target. However, identification of the ideal pathway member to therapeutically target for maximal clinical benefit remains a challenge. In normal cells, the MAPK pathway relays extracellular signals from the cell membrane to the nucleus via a cascade of phosphorylation events, which promote cancer development. Dysregulation of the MAPK pathway occurs frequently in many human cancers including melanoma. Mutations in the B-RAF and RAS genes, genetic or epigenetic modifications are the key aberrations observed in this signaling cascade. Constitutive activation of this pathway causes oncogenic transformation of cells by promoting cell proliferation, invasion, metastasis, migration, survival and angiogenesis. This review provides an overview of (a) key members of MAPK signaling regulating melanoma development; (b) key proteins which can serve as biomarkers to assess disease progression; (c) the clinical efficacy of various pharmacological agents targeting MAPK pathway; (d) current clinical trials evaluating downstream targets of the MAPK pathway; (e) issues associated with pharmacological agents such as drug resistance, induction of cancers; and finally (e) various strategies overcoming drug resistance. PMID:23288642

Left-right asymmetry specification in amphioxus: review and prospects.

PubMed

Soukup, Vladimir

2017-01-01

Extant bilaterally symmetrical animals usually show asymmetry in the arrangement of their inner organs. However, the exaggerated left-right (LR) asymmetry in amphioxus represents a true peculiarity among them. The amphioxus larva shows completely disparate fates of left and right body sides, so that organs associated with pharynx are either positioned exclusively on the left or on the right side. Moreover, segmented paraxial structures such as muscle blocks and their neuronal innervation show offset arrangement between the sides making it difficult to propose any explanation or adaptivity to larval and adult life. First LR asymmetries can be traced back to an early embryonic period when morphological asymmetries are preceded by molecular asymmetries driven by the action of the Nodal signaling pathway. This review sums up recent advances in understanding LR asymmetry specification in amphioxus and proposes upstream events that may regulate asymmetric Nodal signaling. These events include the presence of the vertebrate-like LR organizer and a cilia-driven fluid flow that may be involved in the breaking of bilateral symmetry. The upstream pathways comprising the ion flux, Delta/Notch, Wnt/β-catenin and Wnt/PCP are hypothesized to regulate both formation of the LR organizer and expression of the downstream Nodal signaling pathway genes. These suggestions are in line with what we know from vertebrate and ambulacrarian LR axis specification and are directly testable by experimental manipulations. Thanks to the phylogenetic position of amphioxus, the proposed mechanisms may be helpful in understanding the evolution of LR axis specification across deuterostomes.

New Views on Strand Asymmetry in Insect Mitochondrial Genomes

PubMed Central

Wei, Shu-Jun; Shi, Min; Chen, Xue-Xin; Sharkey, Michael J.; van Achterberg, Cornelis; Ye, Gong-Yin; He, Jun-Hua

2010-01-01

Strand asymmetry in nucleotide composition is a remarkable feature of animal mitochondrial genomes. Understanding the mutation processes that shape strand asymmetry is essential for comprehensive knowledge of genome evolution, demographical population history and accurate phylogenetic inference. Previous studies found that the relative contributions of different substitution types to strand asymmetry are associated with replication alone or both replication and transcription. However, the relative contributions of replication and transcription to strand asymmetry remain unclear. Here we conducted a broad survey of strand asymmetry across 120 insect mitochondrial genomes, with special reference to the correlation between the signs of skew values and replication orientation/gene direction. The results show that the sign of GC skew on entire mitochondrial genomes is reversed in all species of three distantly related families of insects, Philopteridae (Phthiraptera), Aleyrodidae (Hemiptera) and Braconidae (Hymenoptera); the replication-related elements in the A+T-rich regions of these species are inverted, confirming that reversal of strand asymmetry (GC skew) was caused by inversion of replication origin; and finally, the sign of GC skew value is associated with replication orientation but not with gene direction, while that of AT skew value varies with gene direction, replication and codon positions used in analyses. These findings show that deaminations during replication and other mutations contribute more than selection on amino acid sequences to strand compositions of G and C, and that the replication process has a stronger affect on A and T content than does transcription. Our results may contribute to genome-wide studies of replication and transcription mechanisms. PMID:20856815

The influence of sex chromosome aneuploidy on brain asymmetry.

PubMed

Rezaie, Roozbeh; Daly, Eileen M; Cutter, William J; Murphy, Declan G M; Robertson, Dene M W; DeLisi, Lynn E; Mackay, Clare E; Barrick, Thomas R; Crow, Timothy J; Roberts, Neil

2009-01-05

The cognitive deficits present in individuals with sex chromosome aneuploidies suggest that hemispheric differentiation of function is determined by an X-Y homologous gene [Crow (1993); Lancet 342:594-598]. In particular, females with Turner's syndrome (TS) who have only one X-chromosome exhibit deficits of spatial ability whereas males with Klinefelter's syndrome (KS) who possess a supernumerary X-chromosome are delayed in acquiring words. Since spatial and verbal abilities are generally associated with right and left hemispheric function, such deficits may relate to anomalies of cerebral asymmetry. We therefore applied a novel image analysis technique to investigate the relationship between sex chromosome dosage and structural brain asymmetry. Specifically, we tested Crow's prediction that the magnitude of the brain torque (i.e., a combination of rightward frontal and leftward occipital asymmetry) would, as a function of sex chromosome dosage, be respectively decreased in TS women and increased in KS men, relative to genotypically normal controls. We found that brain torque was not significantly different in TS women and KS men, in comparison to controls. However, TS women exhibited significantly increased leftward brain asymmetry, restricted to the posterior of the brain and focused on the superior temporal and parietal-occipital association cortex, while KS men showed a trend for decreased brain asymmetry throughout the frontal lobes. The findings suggest that the number of sex chromosomes influences the development of brain asymmetry not simply to modify the torque but in a complex pattern along the antero-posterior axis. 2008 Wiley-Liss, Inc.

Perceptual asymmetry in texture perception.

PubMed

Williams, D; Julesz, B

1992-07-15

A fundamental property of human visual perception is our ability to distinguish between textures. A concerted effort has been made to account for texture segregation in terms of linear spatial filter models and their nonlinear extensions. However, for certain texture pairs the ease of discrimination changes when the role of figure and ground are reversed. This asymmetry poses a problem for both linear and nonlinear models. We have isolated a property of texture perception that can account for this asymmetry in discrimination: subjective closure. This property, which is also responsible for visual illusions, appears to be explainable by early visual processes alone. Our results force a reexamination of the process of human texture segregation and of some recent models that were introduced to explain it.

Analysis of Facial Asymmetry in Deformational Plagiocephaly Using Three-Dimensional Computed Tomographic Review

PubMed Central

Moon, Il Yung; Oh, Kap Sung

2014-01-01

Background Infants with deformational plagiocephaly (DP) usually present with cranial vault deformities as well as facial asymmetry. The purpose of this study was to use three-dimensional anthropometric data to evaluate the influence of cranial deformities on facial asymmetry. Methods We analyzed three-dimensional computed tomography data for infants with DP (n=48) and without DP (n=30, control). Using 16 landmarks and 3 reference planes, 22 distance parameters and 2 angular parameters were compared. This cephalometric assessment focused on asymmetry of the orbits, nose, ears, maxilla, and mandible. We then assessed the correlation between 23 of the measurements and cranial vault asymmetry (CVA) for statistical significance using relative differences and correlation analysis. Results With the exception of few orbital asymmetry variables, most measurements indicated that the facial asymmetry was greater in infants with DP. Mandibular and nasal asymmetry was correlated highly with severity of CVA. Shortening of the ipsilateral mandibular body was particularly significant. There was no significant deformity in the maxilla or ear. Conclusion This study demonstrated that the cranial vault deformity in DP is associated with facial asymmetry. Compared with the control group, the infants with DP were found to have prominent asymmetry of the nose and mandible. PMID:28913202

The effect of cognitive load on hemispheric asymmetries in true and false memory.

PubMed

Tat, Michael J; Azuma, Tamiko

2016-01-01

Studies examining hemispheric asymmetries in false memory have shown that the right hemisphere (RH) is more susceptible to false memories compared to the left hemisphere (LH). Theories suggest that hemispheric asymmetries in true and false memory may be due to differences in representational coding and the use of top-down mechanisms in each hemisphere. In the current study, the Deese-Roediger-McDermott false memory paradigm was used in conjunction with divided visual field presentation to examine the role of top-down mechanisms in hemispheric asymmetries of true and false memory. In Experiment 1, participants studied lists of related words while completing secondary cognitive load tasks. In Experiment 2, the secondary tasks were administered during memory retrieval instead of memory encoding. Results revealed that cognitive loads imposed during the study phase influenced veridical memory in the LH more than the RH, but cognitive loads imposed during retrieval did not influence veridical memory in either hemisphere. Surprisingly, false memory rates were not influenced by cognitive loads and were higher in the LH. These data provide evidence that, at least for veridical memory, top-down control mechanisms are used more readily for the encoding of information into memory in the LH compared to the RH.

Reappraisal writing relieves social anxiety and may be accompanied by changes in frontal alpha asymmetry

PubMed Central

Wang, Fen; Wang, Changming; Yin, Qin; Wang, Kui; Li, Dongdong; Mao, Mengchai; Zhu, Chaozhe; Huang, Yuxia

2015-01-01

It is widely reported that expressive writing can improve mental and physical health. However, to date, the neural correlates of expressive writing have not been reported. The current study examined the neural electrical correlates of expressive writing in a reappraisal approach. Three groups of participants were required to give a public speech. Before speaking, the reappraisal writing group was asked to write about the current stressful task in a reappraisal manner. The irrelevant writing group was asked to write about their weekly plan, and the non-writing group did not write anything. It was found that following the experimental writing manipulation, both reappraisal and irrelevant writing conditions decreased self-reported anxiety levels. But when re-exposed to the stressful situation, participants in the irrelevant writing group showed increased anxiety levels, while anxiety levels remained lower in the reappraisal group. During the experimental writing manipulation period, participants in the reappraisal group had lower frontal alpha asymmetry scores than those in the irrelevant writing group. However, following re-exposure to stress, participants in the reappraisal group showed higher frontal alpha asymmetry scores than those in the irrelevant writing group. Self-reported anxiety and frontal alpha asymmetry of the non-writing condition did not change significantly across these different stages. It is noteworthy that expressive writing in a reappraisal style seems not to be a fast-acting treatment but may instead take effect in the long run. PMID:26539146

Pegasus, the 'atypical' Ikaros family member, influences left-right asymmetry and regulates pitx2 expression.

PubMed

John, Liza B; Trengove, Monique C; Fraser, Fiona W; Yoong, Simon H; Ward, Alister C

2013-05-01

Members of the Ikaros family of zinc-finger transcription factors have been shown to be critical for immune and blood cell development. However, the role of the most divergent family member, Pegasus, has remained elusive, although it shows conservation to invertebrate Hunchback proteins that influence embryonic patterning through regulation of homeodomain genes. Zebrafish was employed as a relevant model to investigate the function of Pegasus since it possesses a single pegasus orthologue with high homology to its mammalian counterparts. During zebrafish embryogenesis pegasus transcripts were initially maternally-derived and later replaced by zygotic expression in the diencephalon, tectum, hindbrain, thymus, eye, and ultimately the exocrine pancreas and intestine. Morpholino-mediated knockdown of the zebrafish pegasus gene resulted in disrupted left-right asymmetry of the gut and pancreas. Molecular analysis indicated that zebrafish Pegasus localised to the nucleus in discrete non-nucleolar structures and bound the 'atypical' DNA sequence GN3GN2G, confirming its presumed role as a transcriptional regulator. In vivo transcriptome analysis identified candidate target genes, several of which encoded homeodomain transcription factors. One of these, pitx2, implicated in left-right asymmetry, possessed appropriate 'atypical' Pegasus binding sites in its promoter. Knockdown of Pegasus affected both the level and asymmetry of pitx2 expression, as well as disrupting the asymmetry of the lefty2 and spaw genes, explaining the perturbed left-right patterning in pegasus morphants. Collectively these results provide the first definitive insights into the in vivo role of Pegasus, supporting the notion that it acts as a broader regulator of development, with potential parallels to the related invertebrate Hunchback proteins. Copyright © 2013 Elsevier Inc. All rights reserved.

Emotion and resilience: a multilevel investigation of hemispheric electroencephalogram asymmetry and emotion regulation in maltreated and nonmaltreated children.

PubMed

Curtis, W John; Cicchetti, Dante

2007-01-01

The current study was a multilevel investigation of resilience, emotion regulation, and hemispheric electroencephalogram (EEG) asymmetry in a sample of maltreated and nonmaltreated school age children. It was predicted that the positive emotionality and increased emotion regulatory ability associated with resilient functioning would be associated with relatively greater left frontal EEG activity. The study also investigated differences in pathways to resilience between maltreated and nonmaltreated children. The findings indicated that EEG asymmetry across central cortical regions distinguished between resilient and nonresilient children, with greater left hemisphere activity characterizing those who were resilient. In addition, nonmaltreated children showed greater left hemisphere EEG activity across parietal cortical regions. There was also a significant interaction between resilience, maltreatment status, and gender for asymmetry at anterior frontal electrodes, where nonmaltreated resilient females had greater relative left frontal activity compared to more right frontal activity exhibited by resilient maltreated females. An observational measure of emotion regulation significantly contributed to the prediction of resilience in the maltreated and nonmaltreated children, but EEG asymmetry in central cortical regions independently predicted resilience only in the maltreated group. The findings are discussed in terms of their meaning for the development of resilient functioning.

Patterns of directional asymmetry in the pelvis and pelvic canal.

PubMed

Tobolsky, Victoria A; Kurki, Helen K; Stock, Jay T

2016-11-01

The human pelvis is unique among modern taxa for supporting both parturition of large brained young and obligate bipedalism. Though much work has focused on pelvic development and variation, little work has explored the presence or absence of asymmetry in the pelvis despite well-known patterns of asymmetry in other skeletal regions. This study investigated whether patterns of directional asymmetry (DA) could be observed in the pelvis or pelvic canal. Seventeen bilaterally paired osteometric measurements of the os coxae (34 measures in total) were taken from 128 skeletons (female n = 65, male n = 63) from recent human populations in five geographic regions. Paired sample t-tests and Mann-Whitney U-tests were used to investigate DA. Results from a pooled sample of all individuals showed that the pelvis exhibited a left-bias in DA. In contrast, the pelvic canal exhibited a pattern in which the anterior canal exhibited a right-bias and the posterior canal exhibited a left-bias. Neither sex nor populational differences in DA were observed in the pelvis or pelvic canal. The varying patterns of asymmetry uncovered here accord with prior work and may indicate that loading from the trunk and legs place differing stresses on the pelvis and canal, yielding these unequal asymmetries. However, this is speculative and the possible influence of genetics, biomechanics, and nutritional status on the development of pelvic and canal asymmetries presents a rich area for future study. Additionally, the potential influence of pelvic canal asymmetry on obstetric measures of pelvic capacity merits future research. Am. J. Hum. Biol. 28:804-810, 2016. © 2016Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Quantification of upper limb kinetic asymmetries in front crawl swimming.

PubMed

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

2015-04-01

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

Auxin Asymmetry during Gravitropism by Tomato Hypocotyls 1

PubMed Central

Harrison, Marcia A.; Pickard, Barbara G.

1989-01-01

Gravitropic asymmetry of auxin was observed in hypocotyls of tomato (Lycopersicon esculentum Mill.) soon after horizontal placement: the ratio of apically supplied [3H]IAA collected from the lower sides to that from the upper sides was about 1.4 between 5 and 10 minutes. This was adequately early to account for the beginning of curvature. The auxin asymmetry ratio rose to about 2.5 between 20 and 25 minutes, and to 3.5 during the main phase of curvature. This compares reasonably well with the roughly 3.9 ratio for elongation on the lower side to elongation on the upper side that is the basis for the curvature. These data extend evidence that the Went-Cholodny theory for the mediation of tropisms is valid for dicot stems. Also consistent with the theory, an auxin asymmetry ratio of 2.5 was observed when wrong-way gravitropic curvature developed following application of a high level of auxin. In addition to reversing the asymmetry of elongation, the large supplement of auxin resulted in lower net elongation. Previous data established that ethylene is not involved in this decrease of growth as a function of increasing level of auxin. PMID:11537450

Resolving Multi-Stakeholder Robustness Asymmetries in Coupled Agricultural and Urban Systems

NASA Astrophysics Data System (ADS)

Li, Yu; Giuliani, Matteo; Castelletti, Andrea; Reed, Patrick

2016-04-01

The evolving pressures from a changing climate and society are increasingly motivating decision support frameworks that consider the robustness of management actions across many possible futures. Focusing on robustness is helpful for investigating key vulnerabilities within current water systems and for identifying potential tradeoffs across candidate adaptation responses. To date, most robustness studies assume a social planner perspective by evaluating highly aggregated measures of system performance. This aggregate treatment of stakeholders does not explore the equity or intrinsic multi-stakeholder conflicts implicit to the system-wide measures of performance benefits and costs. The commonly present heterogeneity across complex management interests, however, may produce strong asymmetries for alternative adaptation options, designed to satisfy system-level targets. In this work, we advance traditional robustness decision frameworks by replacing the centralized social planner with a bottom-up, agent-based approach, where stakeholders are modeled as individuals, and represented as potentially self-interested agents. This agent-based model enables a more explicit exploration of the potential inequities and asymmetries in the distribution of the system-wide benefit. The approach is demonstrated by exploring the potential conflicts between urban flooding and agricultural production in the Lake Como system (Italy). Lake Como is a regulated lake that is operated to supply water to the downstream agricultural district (Muzza as the pilot study area in this work) composed of a set of farmers with heterogeneous characteristics in terms of water allocation, cropping patterns, and land properties. Supplying water to farmers increases the risk of floods along the lakeshore and therefore the system is operated based on the tradeoff between these two objectives. We generated an ensemble of co-varying climate and socio-economic conditions and evaluated the robustness of the

Determination of the scalar polarizabilities of the proton using beam asymmetry $$\\Sigma_{3}$$ in Compton scattering

DOE PAGES

Sokhoyan, V.; Downie, E. J.; Mornacchi, E.; ...

2017-01-01

The scalar dipole polarizabilities, α E1 and β M1, are fundamental properties related to the internal dynamics of the nucleon. The currently accepted values of the proton polarizabilities were determined by fitting to unpolarized proton Compton scattering cross section data. The measurement of the beam asymmetry Σ 3 in a certain kinematical range provides an alternative approach to the extraction of the scalar polarizabilities. At the Mainz Microtron (MAMI) the beam asymmetry was measured for Compton scattering below pion photoproduction threshold for the first time. Finally, the results are compared with model calculations and the influence of the experimental datamore » on the extraction of the scalar polarizabilities is determined.« less

Right hemisphere dominance during spatial selective attention and target detection occurs outside the dorsal fronto-parietal network

PubMed Central

Shulman, Gordon L.; Pope, Daniel L. W.; Astafiev, Serguei V.; McAvoy, Mark P.; Snyder, Abraham Z.; Corbetta, Maurizio

2010-01-01

Spatial selective attention is widely considered to be right hemisphere dominant. Previous functional magnetic resonance imaging (fMRI) studies, however, have reported bilateral blood-oxygenation-level-dependent (BOLD) responses in dorsal fronto-parietal regions during anticipatory shifts of attention to a location (Kastner et al., 1999; Corbetta et al., 2000; Hopfinger et al., 2000). Right-lateralized activity has mainly been reported in ventral fronto-parietal regions for shifts of attention to an unattended target stimulus (Arrington et al., 2000; Corbetta et al., 2000). However, clear conclusions cannot be drawn from these studies because hemispheric asymmetries were not assessed using direct voxel-wise comparisons of activity in left and right hemispheres. Here, we used this technique to measure hemispheric asymmetries during shifts of spatial attention evoked by a peripheral cue stimulus and during target detection at the cued location. Stimulus-driven shifts of spatial attention in both visual fields evoked right-hemisphere dominant activity in temporo-parietal junction (TPJ). Target detection at the attended location produced a more widespread right hemisphere dominance in frontal, parietal, and temporal cortex, including the TPJ region asymmetrically activated during shifts of spatial attention. However, hemispheric asymmetries were not observed during either shifts of attention or target detection in the dorsal fronto-parietal regions (anterior precuneus, medial intraparietal sulcus, frontal eye fields) that showed the most robust activations for shifts of attention. Therefore, right hemisphere dominance during stimulus-driven shifts of spatial attention and target detection reflects asymmetries in cortical regions that are largely distinct from the dorsal fronto-parietal network involved in the control of selective attention. PMID:20219998

Believing in paranormal phenomena: relations to asymmetry of body and brain.

PubMed

Schulter, Günter; Papousek, Ilona

2008-01-01

The goal of this study was to investigate the possible relationship between established measures of body and brain asymmetries and individual differences in paranormal beliefs. In addition to behavioural measures of cerebral laterality, measures of facial features and finger length were taken to calculate body asymmetry scores and indicators of fluctuating asymmetry (average absolute differences between left and right body features). Both the direction and degree of laterality measures were used. In addition to that, quantitative measures of inconsistency of cerebral lateralization were obtained. Results indicated that a stronger belief in paranormal phenomena was associated with fluctuating asymmetry of finger length, and that this aspect of body asymmetry may be related to greater intraindividual variability in the degree of 'atypical' functional lateralization. This intraindividual variability index, in turn, significantly predicted strength of belief in the paranormal. Belief in the paranormal was also higher in women than men and it was negatively correlated with the education level. In sum, these findings suggest that a part of the variance of strength of belief in paranormal phenomena can be explained by patterns of functional hemispheric asymmetry that may be related to perturbations during fetal development.

Disentangling the Relationship between Hemispheric Asymmetry and Cognitive Performance

ERIC Educational Resources Information Center

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

2010-01-01

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

Postural asymmetries in young adults with cerebral palsy

PubMed Central

Rodby-Bousquet, Elisabet; Czuba, Tomasz; Hägglund, Gunnar; Westbom, Lena

2013-01-01

Aim The purpose was to describe posture, ability to change position, and association between posture and contractures, hip dislocation, scoliosis, and pain in young adults with cerebral palsy (CP). Methods Cross-sectional data of 102 people (63 males, 39 females; age range 19–23y, median 21y) out of a total population with CP was analysed in relation to Gross Motor Function Classification System (GMFCS) levels I (n=38), II (n=21), III (n=13), IV (n=10), and V (n=20). The CP subtypes were unilateral spastic (n=26), bilateral spastic (n=45), ataxic (n=12), and dyskinetic CP (n=19). The Postural Ability Scale was used to assess posture. The relationship between posture and joint range of motion, hip dislocation, scoliosis, and pain was analysed using logistic regression and Spearman’s correlation. Results At GMFCS levels I to II, head and trunk asymmetries were most common; at GMFCS levels III to V postural asymmetries varied with position. The odds ratios (OR) for severe postural asymmetries were significantly higher for those with scoliosis (OR=33 sitting), limited hip extension (OR=39 supine), or limited knee extension (OR=37 standing). Postural asymmetries correlated to hip dislocations: supine (rs=0.48), sitting (rs=0.40), standing (rs=0.41), and inability to change position: supine (rs=0.60), sitting (rs=0.73), and standing (rs=0.64). Conclusions Postural asymmetries were associated with scoliosis, hip dislocations, hip and knee contractures, and inability to change position. This article is commented on by Novak on page 974 of this issue. PMID:23834239

Sex differences in oral asymmetries during wordrepetition.

PubMed

Hausmann, M; Behrendt-Körbitz, S; Kautz, H; Lamm, C; Radelt, F; Güntürkün, O

1998-12-01

During speech production the right side of the mouth is opened to a larger degree in most people. This facial asymmetry is thought to be related to a left hemisphere dominance in language processing and/or motor programming. We investigated asymmetrical lip separations during discrete or serial word productions in right handed persons. The results revealed a right sided lip separation bias in both genders during discrete word production in which the words had to be uttered once. As soon as the words had to be produced continuously, however, a clear sex difference appeared with males having the usual right bias but females now showing no clear asymmetry, with a tendency for larger lip separations on the left side. These results suggest the existence of two separate neural systems from which one controls the discrete task and which is left hemisphere dominant in both genders. The other is probably involved in serial word productions and shows a sex difference with regard to its asymmetry pattern.

Cranium asymmetry in a modern Greek population sample of known age and sex.

PubMed

Chovalopoulou, Maria-Eleni; Papageorgopoulou, Christina; Bertsatos, Andreas

2017-05-01

The aim of this paper is to evaluate and quantify cranium asymmetry, sexual differences in the set of individual asymmetry scores, and the relationship between fluctuating asymmetry and age, in a modern Greek population sample. In addition, we test for the developmental origins of health and disease hypothesis by assessing the correlation between fluctuating asymmetry and cause of death. The study sample consisted of 173 crania of known sex and adult age (92 males, 81 females) belonging to individuals who lived in Greece during the twentieth century. The three-dimensional coordinates of 77 ectocranial landmarks were digitized using a Microscribe 3DX contact digitizer and landmark configurations were analyzed using the generalized least-squares Procrustes method. Regarding directional asymmetry, the results show that the human skull has a tendency for a left-side excess for the Greek population. No significant directional asymmetry differences between the sexes are found. The highest levels of fluctuating asymmetry for both sexes are located on the skull base. The levels of fluctuating asymmetry in all cranial regions appear higher for males than females. Nevertheless, these differences do not present any statistical significance between sexes. Additionally, there is no relationship between fluctuating asymmetry scores and age for both males and females. Finally, the results of this study could not confirm that early development has a significant impact on adult health outcomes.

Σ beam asymmetry for K^+ photoproduction by linearly polarized photon beam at SPring-8/LEPS

NASA Astrophysics Data System (ADS)

Sumihama, Mizuki

2001-10-01

The K^+ photoproduction provides important information on the hadronic physics with strangeness. The reaction allows the investigation of the nucleon resonances which are predicted by theoretical calculations with three constituent valence quarks but have not been observed in πN arrow πN channel. Quark model studies suggest those missing resonances may couple to other channels, such as channels with strangeness. Recently, total cross section data of the p(γ,K^+)Λ reaction at ELSA/SAPHIR(M.Q.Tran et al., Phys. Lett. B445(1998)20-26) show a resonance structure around 1900 MeV. The other observables would give more information to the existence and structure of this resonance. Especially the Σ beam asymmetry would benefit theoretical studies because this observable is quite sensitive to the existence of missing nucleon resonances which couple strongly to K^+Λ or K^+Σ^0. The Σ beam asymmetry for p(γ,K^+)Λ and p(γ,K^+)Σ^0 reactions will be obtained using the linearly polarized photon beam at SPring-8/LEPS. The experiment of the hadron photoproduction using the linearly polarized photon beam and liquid hydrogen target started at the LEPS beamline. Data of the hadron photoproduction has been taken from December 2000 until June 2001. The results of Σ beam asymmetry will be presented and discussed.

Social modeling of eating mediated by mirror neuron activity: A causal model moderated by frontal asymmetry and BMI.

PubMed

McGeown, Laura; Davis, Ron

2018-02-15

The social modeling of eating effect refers to the consistently demonstrated phenomenon that individuals tend to match their quantity of food intake to their eating companion. The current study sought to explore whether activity within the mirror neuron system (MNS) mediates the social modeling of eating effect as a function of EEG frontal asymmetry and body mass index (BMI). Under the guise of rating empathy, 93 female undergraduates viewed a female video confederate "incidentally" consume either a low or high intake of chips while electroencephalogram (EEG) activity was recorded. Subsequent ad libitum chip consumption was quantified. A first- and second-stage dual moderation model revealed that frontal asymmetry and BMI moderated an indirect effect of model consumption on participants' food consumption as mediated by MNS activity at electrode site C3, a 3 b 3 =-0.718, SE=0.365, 95% CI [-1.632, -0.161]. Left frontal asymmetry was associated with greater mu activity and a positive association between model and participant chip consumption, while right frontal asymmetry was associated with less mu activity and a negative association between model and participant consumption. Across all levels of frontal asymmetry, the effect was only significant among those with a BMI at the 50th percentile or lower. Thus, among leaner individuals, the MNS was demonstrated to mediate social modeling of eating, as moderated by frontal asymmetry. These findings are integrated within the normative account of social modeling of eating. It is proposed that the normative framework may benefit from consideration of both conscious and unconscious operation of intake norms. Copyright © 2017 Elsevier B.V. All rights reserved.

Growth models and the expected distribution of fluctuating asymmetry

USGS Publications Warehouse

Graham, John H.; Shimizu, Kunio; Emlen, John M.; Freeman, D. Carl; Merkel, John

2003-01-01

Multiplicative error accounts for much of the size-scaling and leptokurtosis in fluctuating asymmetry. It arises when growth involves the addition of tissue to that which is already present. Such errors are lognormally distributed. The distribution of the difference between two lognormal variates is leptokurtic. If those two variates are correlated, then the asymmetry variance will scale with size. Inert tissues typically exhibit additive error and have a gamma distribution. Although their asymmetry variance does not exhibit size-scaling, the distribution of the difference between two gamma variates is nevertheless leptokurtic. Measurement error is also additive, but has a normal distribution. Thus, the measurement of fluctuating asymmetry may involve the mixing of additive and multiplicative error. When errors are multiplicative, we recommend computing log E(l) − log E(r), the difference between the logarithms of the expected values of left and right sides, even when size-scaling is not obvious. If l and r are lognormally distributed, and measurement error is nil, the resulting distribution will be normal, and multiplicative error will not confound size-related changes in asymmetry. When errors are additive, such a transformation to remove size-scaling is unnecessary. Nevertheless, the distribution of l − r may still be leptokurtic.

Hemispherical and Longitudinal Asymmetries in the Heliospheric Magnetic Field: Flip-flops of a Bashful Ballerina

NASA Astrophysics Data System (ADS)

Hiltula, T.; Mursula, K.

2004-12-01

Several studies during many decennia have studied possible longitudinal and hemispherical asymmetries in various forms of solar activity. E.g., there are well known periods when one of the solar hemispheres has dominated the other in sunspot numbers, flare occurrence or some other form of solar activity. However, the solar asymmetries have not been found to be very conclusive, or to form any clear systematical patterns (e.g., relation to solar cycle). On the contrary, recent studies of similar longitudinal and hemispherical asymmetries in the heliospheric magnetic field have shown a very clear and systematic behaviour. E.g., it was found recently that the dominance of the two HMF sectors experiences an oscillation with a period of about 3.2 years. This new flip-flop periodicity in the heliospheric magnetic field is most likely related to a similar periodicity recently found in sunspots. Also, it has recently been found that the HMF sector coming from the northern solar hemisphere systematically dominates at 1AU during solar minimum times. This leads to a persistent southward shift or coning of the heliospheric current sheet at these times that can be picturesquely described by the concept of a Bashful Ballerina. This result also implies that the Sun has a large-scale quadrupole magnetic moment. Here we review these recent developments concerning the longitudinal and hemispherical asymmetries in the heliospheric magnetic field and study their inter-connection.

Voxel-wise grey matter asymmetry analysis in left- and right-handers.

PubMed

Ocklenburg, Sebastian; Friedrich, Patrick; Güntürkün, Onur; Genç, Erhan

2016-10-28

Handedness is thought to originate in the brain, but identifying its structural correlates in the cortex has yielded surprisingly incoherent results. One idea proclaimed by several authors is that structural grey matter asymmetries might underlie handedness. While some authors have found significant associations with handedness in different brain areas (e.g. in the central sulcus and precentral sulcus), others have failed to identify such associations. One method used by many researchers to determine structural grey matter asymmetries is voxel based morphometry (VBM). However, it has recently been suggested that the standard VBM protocol might not be ideal to assess structural grey matter asymmetries, as it establishes accurate voxel-wise correspondence across individuals but not across both hemispheres. This could potentially lead to biased and incoherent results. Recently, a new toolbox specifically geared at assessing structural asymmetries and involving accurate voxel-wise correspondence across hemispheres has been published [F. Kurth, C. Gaser, E. Luders. A 12-step user guide for analyzing voxel-wise gray matter asymmetries in statistical parametric mapping (SPM), Nat Protoc 10 (2015), 293-304]. Here, we used this new toolbox to re-assess grey matter asymmetry differences in left- vs. right-handers and linked them to quantitative measures of hand preference and hand skill. While we identified several significant left-right asymmetries in the overall sample, no difference between left- and right-handers reached significance after correction for multiple comparisons. These findings indicate that the structural brain correlates of handedness are unlikely to be rooted in macroscopic grey matter area differences that can be assessed with VBM. Future studies should focus on other potential structural correlates of handedness, e.g. structural white matter asymmetries. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

SIMULATION STUDY OF HEMISPHERIC PHASE-ASYMMETRY IN THE SOLAR CYCLE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shukuya, D.; Kusano, K., E-mail: kusano@nagoya-u.jp

2017-01-20

Observations of the Sun suggest that solar activities systematically create north–south hemispheric asymmetries. For instance, the hemisphere in which sunspot activity is more active tends to switch after the early half of each solar cycle. Svalgaard and Kamide recently pointed out that the time gaps of polar field reversal between the northern and southern hemispheres are simply consequences of the asymmetry of sunspot activity. However, the mechanism underlying the asymmetric feature in solar cycle activity is not yet well understood. In this paper, in order to explain the cause of the asymmetry from the theoretical point of view, we investigatemore » the relationship between the dipole- and quadrupole-type components of the magnetic field in the solar cycle using the mean-field theory based on the flux transport dynamo model. As a result, we found that there are two different attractors of the solar cycle, in which either the north or the south polar field is first reversed, and that the flux transport dynamo model explains well the phase-asymmetry of sunspot activity and the polar field reversal without any ad hoc source of asymmetry.« less

Hemispheric asymmetry and theory of mind: is there an association?

PubMed

Herzig, Daniela A; Sullivan, Sarah; Evans, Jonathan; Corcoran, Rhiannon; Mohr, Christine

2012-01-01

In autism and schizophrenia attenuated/atypical functional hemispheric asymmetry and theory of mind impairments have been reported, suggesting common underlying neuroscientific correlates. We here investigated whether impaired theory of mind performance is associated with attenuated/atypical hemispheric asymmetry. An association may explain the co-occurrence of both dysfunctions in psychiatric populations. Healthy participants (n=129) performed a left hemisphere (lateralised lexical decision task) and right hemisphere (lateralised face decision task) dominant task as well as a visual cartoon task to assess theory of mind performance. Linear regression analyses revealed inconsistent associations between theory of mind performance and functional hemisphere asymmetry: enhanced theory of mind performance was only associated with (1) faster right hemisphere language processing, and (2) reduced right hemisphere dominance for face processing (men only). The majority of non-significant findings suggest that theory of mind and functional hemispheric asymmetry are unrelated. Instead of "overinterpreting" the two significant results, discrepancies in the previous literature relating to the problem of the theory of mind concept, the variety of tasks, and the lack of normative data are discussed. We also suggest how future studies could explore a possible link between hemispheric asymmetry and theory of mind.

Fetal origin of the posterior cerebral artery produces left-right asymmetry on perfusion imaging.

PubMed

Wentland, A L; Rowley, H A; Vigen, K K; Field, A S

2010-03-01

Fetal origin of the PCA is a common anatomic variation of the circle of Willis. On perfusion imaging, patients with unilateral fetal-type PCA may demonstrate left-right asymmetry that could mimic cerebrovascular disease. The aim of this study was to characterize the relationship between a fetal-type PCA and asymmetry of hemodynamic parameters derived from MR perfusion imaging. We retrospectively reviewed MR perfusion studies of 36 patients to determine the relationship between hemodynamic and vascular asymmetries in the PCA territory. Perfusion asymmetry indices for the PCA territory were computed from maps of rCBF, rCBV, MTT, T(max), and FMT. Vascular asymmetry indices were derived from calibers of the PCA-P1 segments relative to the posterior communicating arteries. Asymmetrically smaller values of FMT and T(max) were observed with unilateral fetal-type PCA, and these were strongly correlated with the degree of vascular asymmetry (Spearman's rho = 0.76 and 0.74, respectively, P < 1 x 10(-6)). Asymmetries of rCBF, MTT, and rCBV were neither significant nor related to vascular asymmetry. Faster perfusion transit times are seen for parameters sensitive to macrovascular transit effects (eg, FMT and T(max)) ipsilateral to fetal origin of the PCA in proportion to the degree of arterial asymmetry. Knowledge of this normal variation is critical in the interpretation of perfusion studies because asymmetry could mimic cerebrovascular pathology.

Frontal alpha asymmetry neurofeedback for the reduction of negative affect and anxiety.

PubMed

Mennella, Rocco; Patron, Elisabetta; Palomba, Daniela

2017-05-01

Frontal alpha asymmetry has been proposed to underlie the balance between approach and withdrawal motivation associated to each individual's affective style. Neurofeedback of EEG frontal alpha asymmetry represents a promising tool to reduce negative affect, although its specific effects on left/right frontal activity and approach/withdrawal motivation are still unclear. The present study employed a neurofeedback training to increase frontal alpha asymmetry (right - left), in order to evaluate discrete changes in alpha power at left and right sites, as well as in positive and negative affect, anxiety and depression. Thirty-two right-handed females were randomly assigned to receive either the neurofeedback on frontal alpha asymmetry, or an active control training (N = 16 in each group). The asymmetry group showed an increase in alpha asymmetry driven by higher alpha at the right site (p < 0.001), as well as a coherent reduction in both negative affect and anxiety symptoms (ps < 0.05), from pre-to post-training. No training-specific modulation emerged for positive affect and depressive symptoms. These findings provide a strong rationale for the use of frontal alpha asymmetry neurofeedback for the reduction of negative affect and anxiety in clinical settings. Copyright © 2017 Elsevier Ltd. All rights reserved.

HEMISPHERIC ASYMMETRIES OF SOLAR PHOTOSPHERIC MAGNETISM: RADIATIVE, PARTICULATE, AND HELIOSPHERIC IMPACTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

McIntosh, Scott W.; Burkepile, Joan; Miesch, Mark

2013-03-10

Among many other measurable quantities, the summer of 2009 saw a considerable low in the radiative output of the Sun that was temporally coincident with the largest cosmic-ray flux ever measured at 1 AU. Combining measurements and observations made by the Solar and Heliospheric Observatory (SOHO) and Solar Dynamics Observatory (SDO) spacecraft we begin to explore the complexities of the descending phase of solar cycle 23, through the 2009 minimum into the ascending phase of solar cycle 24. A hemispheric asymmetry in magnetic activity is clearly observed and its evolution monitored and the resulting (prolonged) magnetic imbalance must have hadmore » a considerable impact on the structure and energetics of the heliosphere. While we cannot uniquely tie the variance and scale of the surface magnetism to the dwindling radiative and particulate output of the star, or the increased cosmic-ray flux through the 2009 minimum, the timing of the decline and rapid recovery in early 2010 would appear to inextricably link them. These observations support a picture where the Sun's hemispheres are significantly out of phase with each other. Studying historical sunspot records with this picture in mind shows that the northern hemisphere has been leading since the middle of the last century and that the hemispheric ''dominance'' has changed twice in the past 130 years. The observations presented give clear cause for concern, especially with respect to our present understanding of the processes that produce the surface magnetism in the (hidden) solar interior-hemispheric asymmetry is the normal state-the strong symmetry shown in 1996 was abnormal. Further, these observations show that the mechanism(s) which create and transport the magnetic flux are slowly changing with time and, it appears, with only loose coupling across the equator such that those asymmetries can persist for a considerable time. As the current asymmetry persists and the basal energetics of the system continue to

Absence of Auditory M100 Source Asymmetry in Schizophrenia and Bipolar Disorder: A MEG Study

PubMed Central

Wang, Ying; Feng, Yigang; Jia, Yanbin; Xie, Yanping; Wang, Wensheng; Guan, Yufang; Zhong, Shuming; Zhu, Dan; Huang, Li

2013-01-01

Background Whether schizophrenia and bipolar disorder are the clinical outcomes of discrete or shared causative processes is much debated in psychiatry. Several studies have demonstrated anomalous structural and functional superior temporal gyrus (STG) symmetries in schizophrenia. We examined bipolar patients to determine if they also have altered STG asymmetry. Methods Whole-head magnetoencephalography (MEG) recordings of auditory evoked fields were obtained for 20 subjects with schizophrenia, 20 with bipolar disorder, and 20 control subjects. Neural generators of the M100 auditory response were modeled using a single equivalent current dipole for each hemisphere. The source location of the M100 response was used as a measure of functional STG asymmetry. Results Control subjects showed the typical M100 asymmetrical pattern with more anterior sources in the right STG. In contrast, both schizophrenia and bipolar disorder patients displayed a symmetrical M100 source pattern. There was no significant difference in the M100 latency and strength in bilateral hemispheres within three groups. Conclusions Our results indicate that disturbed asymmetry of temporal lobe function may reflect a common deviance present in schizophrenia and bipolar disorder, suggesting the two disorders might share etiological and pathophysiological factors. PMID:24340052

Yield asymmetry design of magnesium alloys by integrated computational materials engineering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Dongsheng; Joshi, Vineet; Lavender, Curt

2013-11-01

Deformation asymmetry of magnesium alloys is an important factor on machine design in the automobile industry. Represented by the ratio of compressive yield stress (CYS) against tensile yield stress (TYS), deformation asymmetry is strongly related to texture and grain size. A polycrystalline viscoplasticity model, modified intermediate Φ-model, is used to predict the deformation behavior of magnesium alloys with different grain sizes. Validated with experimental results, integrated computational materials engineering is applied to find out the route in achieving desired asymmetry via thermomechanical processing. For example, CYS/TYS in rolled texture is smaller than 1 under different loading directions. In other textures,more » such as extruded texture, CYS/TYS is large along the normal direction. Starting from rolled texture, asymmetry will increase to close to 1 along the rolling direction after being compressed to a strain of 0.2. Our modified Φ-model also shows that grain refinement increases CYS/TYS. Along with texture control, grain refinement also can optimize the yield asymmetry. After the grain size decreases to a critical value, CYS/TYS reaches to 1 because CYS increases much faster than TYS. By tailoring the microstructure using texture control and grain refinement, it is achievable to optimize yield asymmetry in wrought magnesium alloys.« less

Scale-dependent cyclone-anticyclone asymmetry in a forced rotating turbulence experiment

NASA Astrophysics Data System (ADS)

Gallet, B.; Campagne, A.; Cortet, P.-P.; Moisy, F.

2014-03-01

We characterize the statistical and geometrical properties of the cyclone-anticyclone asymmetry in a statistically steady forced rotating turbulence experiment. Turbulence is generated by a set of vertical flaps which continuously inject velocity fluctuations towards the center of a tank mounted on a rotating platform. We first characterize the cyclone-anticyclone asymmetry from conventional single-point vorticity statistics. We propose a phenomenological model to explain the emergence of the asymmetry in the experiment, from which we predict scaling laws for the root-mean-square velocity in good agreement with the experimental data. We further quantify the cyclone-anticyclone asymmetry using a set of third-order two-point velocity correlations. We focus on the correlations which are nonzero only if the cyclone-anticyclone symmetry is broken. They offer two advantages over single-point vorticity statistics: first, they are defined from velocity measurements only, so an accurate resolution of the Kolmogorov scale is not required; second, they provide information on the scale-dependence of the cyclone-anticyclone asymmetry. We compute these correlation functions analytically for a random distribution of independent identical vortices. These model correlations describe well the experimental ones, indicating that the cyclone-anticyclone asymmetry is dominated by the large-scale long-lived cyclones.

Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron

NASA Astrophysics Data System (ADS)

Aaltonen, T.; Abazov, V. M.; Abbott, B.; Acharya, B. S.; Adams, M.; Adams, T.; Agnew, J. P.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A.; Antos, J.; Apollinari, G.; Appel, J. A.; Arisawa, T.; Artikov, A.; Asaadi, J.; Ashmanskas, W.; Askew, A.; Atkins, S.; Auerbach, B.; Augsten, K.; Aurisano, A.; Aushev, V.; Aushev, Y.; Avila, C.; Azfar, F.; Badaud, F.; Badgett, W.; Bae, T.; Bagby, L.; Baldin, B.; Bandurin, D. V.; Banerjee, S.; Barbaro-Galtieri, A.; Barberis, E.; Baringer, P.; Barnes, V. E.; Barnett, B. A.; Barria, P.; Bartlett, J. F.; Bartos, P.; Bassler, U.; Bauce, M.; Bazterra, V.; Bean, A.; Bedeschi, F.; Begalli, M.; Behari, S.; Bellantoni, L.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Beretvas, A.; Beri, S. B.; Bernardi, G.; Bernhard, R.; Bertram, I.; Besançon, M.; Beuselinck, R.; Bhat, P. C.; Bhatia, S.; Bhatnagar, V.; Bhatti, A.; Bland, K. R.; Blazey, G.; Blessing, S.; Bloom, K.; Blumenfeld, B.; Bocci, A.; Bodek, A.; Boehnlein, A.; Boline, D.; Boos, E. E.; Borissov, G.; Bortoletto, D.; Borysova, M.; Boudreau, J.; Boveia, A.; Brandt, A.; Brandt, O.; Brigliadori, L.; Brochmann, M.; Brock, R.; Bromberg, C.; Bross, A.; Brown, D.; Brucken, E.; Bu, X. B.; Budagov, J.; Budd, H. S.; Buehler, M.; Buescher, V.; Bunichev, V.; Burdin, S.; Burkett, K.; Busetto, G.; Bussey, P.; Buszello, C. P.; Butti, P.; Buzatu, A.; Calamba, A.; Camacho-Pérez, E.; Camarda, S.; Campanelli, M.; Canelli, F.; Carls, B.; Carlsmith, D.; Carosi, R.; Carrillo, S.; Casal, B.; Casarsa, M.; Casey, B. C. K.; Castilla-Valdez, H.; Castro, A.; Catastini, P.; Caughron, S.; Cauz, D.; Cavaliere, V.; Cerri, A.; Cerrito, L.; Chakrabarti, S.; Chan, K. M.; Chandra, A.; Chapelain, A.; Chapon, E.; Chen, G.; Chen, Y. C.; Chertok, M.; Chiarelli, G.; Chlachidze, G.; Cho, K.; Cho, S. W.; Choi, S.; Chokheli, D.; Choudhary, B.; Cihangir, S.; Claes, D.; Clark, A.; Clarke, C.; Clutter, J.; Convery, M. E.; Conway, J.; Cooke, M.; Cooper, W. E.; Corbo, M.; Corcoran, M.; Cordelli, M.; Couderc, F.; Cousinou, M.-C.; Cox, C. A.; Cox, D. J.; Cremonesi, M.; Cruz, D.; Cuevas, J.; Culbertson, R.; Cuth, J.; Cutts, D.; Das, A.; d'Ascenzo, N.; Datta, M.; Davies, G.; de Barbaro, P.; de Jong, S. J.; De La Cruz-Burelo, E.; Déliot, F.; Demina, R.; Demortier, L.; Deninno, M.; Denisov, D.; Denisov, S. P.; D'Errico, M.; Desai, S.; Deterre, C.; DeVaughan, K.; Devoto, F.; Di Canto, A.; Di Ruzza, B.; Diehl, H. T.; Diesburg, M.; Ding, P. F.; Dittmann, J. R.; Dominguez, A.; Donati, S.; D'Onofrio, M.; Dorigo, M.; Driutti, A.; Drutskoy, A.; Dubey, A.; Dudko, L. V.; Duperrin, A.; Dutt, S.; Eads, M.; Ebina, K.; Edgar, R.; Edmunds, D.; Elagin, A.; Ellison, J.; Elvira, V. D.; Enari, Y.; Erbacher, R.; Errede, S.; Esham, B.; Evans, H.; Evdokimov, A.; Evdokimov, V. N.; Farrington, S.; Fauré, A.; Feng, L.; Ferbel, T.; Fernández Ramos, J. P.; Fiedler, F.; Field, R.; Filthaut, F.; Fisher, W.; Fisk, H. E.; Flanagan, G.; Forrest, R.; Fortner, M.; Fox, H.; Franc, J.; Franklin, M.; Freeman, J. C.; Frisch, H.; Fuess, S.; Funakoshi, Y.; Galloni, C.; Garbincius, P. H.; Garcia-Bellido, A.; García-González, J. A.; Garfinkel, A. F.; Garosi, P.; Gavrilov, V.; Geng, W.; Gerber, C. E.; Gerberich, H.; Gerchtein, E.; Gershtein, Y.; Giagu, S.; Giakoumopoulou, V.; Gibson, K.; Ginsburg, C. M.; Ginther, G.; Giokaris, N.; Giromini, P.; Glagolev, V.; Glenzinski, D.; Gogota, O.; Gold, M.; Goldin, D.; Golossanov, A.; Golovanov, G.; Gomez, G.; Gomez-Ceballos, G.; Goncharov, M.; González López, O.; Gorelov, I.; Goshaw, A. T.; Goulianos, K.; Gramellini, E.; Grannis, P. D.; Greder, S.; Greenlee, H.; Grenier, G.; Gris, Ph.; Grivaz, J.-F.; Grohsjean, A.; Grosso-Pilcher, C.; Grünendahl, S.; Grünewald, M. W.; Guillemin, T.; Guimaraes da Costa, J.; Gutierrez, G.; Gutierrez, P.; Hahn, S. R.; Haley, J.; Han, J. Y.; Han, L.; Happacher, F.; Hara, K.; Harder, K.; Hare, M.; Harel, A.; Harr, R. F.; Harrington-Taber, T.; Hatakeyama, K.; Hauptman, J. M.; Hays, C.; Hays, J.; Head, T.; Hebbeker, T.; Hedin, D.; Hegab, H.; Heinrich, J.; Heinson, A. P.; Heintz, U.; Hensel, C.; Heredia-De La Cruz, I.; Herndon, M.; Herner, K.; Hesketh, G.; Hildreth, M. D.; Hirosky, R.; Hoang, T.; Hobbs, J. D.; Hocker, A.; Hoeneisen, B.; Hogan, J.; Hohlfeld, M.; Holzbauer, J. L.; Hong, Z.; Hopkins, W.; Hou, S.; Howley, I.; Hubacek, Z.; Hughes, R. E.; Husemann, U.; Hussein, M.; Huston, J.; Hynek, V.; Iashvili, I.; Ilchenko, Y.; Illingworth, R.; Introzzi, G.; Iori, M.; Ito, A. S.; Ivanov, A.; Jabeen, S.; Jaffré, M.; James, E.; Jang, D.; Jayasinghe, A.; Jayatilaka, B.; Jeon, E. J.; Jeong, M. S.; Jesik, R.; Jiang, P.; Jindariani, S.; Johns, K.; Johnson, E.; Johnson, M.; Jonckheere, A.; Jones, M.; Jonsson, P.; Joo, K. K.; Joshi, J.; Jun, S. Y.; Jung, A. W.; Junk, T. R.; Juste, A.; Kajfasz, E.; Kambeitz, M.; Kamon, T.; Karchin, P. E.; Karmanov, D.; Kasmi, A.; Kato, Y.; Katsanos, I.; Kaur, M.; Kehoe, R.; Kermiche, S.; Ketchum, W.; Keung, J.; Khalatyan, N.; Khanov, A.; Kharchilava, A.; Kharzheev, Y. N.; Kilminster, B.; Kim, D. H.; Kim, H. S.; Kim, J. E.; Kim, M. J.; Kim, S. H.; Kim, S. B.; Kim, Y. J.; Kim, Y. K.; Kimura, N.; Kirby, M.; Kiselevich, I.; Kohli, J. M.; Kondo, K.; Kong, D. J.; Konigsberg, J.; Kotwal, A. V.; Kozelov, A. V.; Kraus, J.; Kreps, M.; Kroll, J.; Kruse, M.; Kuhr, T.; Kumar, A.; Kupco, A.; Kurata, M.; Kurča, T.; Kuzmin, V. A.; Laasanen, A. T.; Lammel, S.; Lammers, S.; Lancaster, M.; Lannon, K.; Latino, G.; Lebrun, P.; Lee, H. S.; Lee, H. S.; Lee, J. S.; Lee, S. W.; Lee, W. M.; Lei, X.; Lellouch, J.; Leo, S.; Leone, S.; Lewis, J. D.; Li, D.; Li, H.; Li, L.; Li, Q. Z.; Lim, J. K.; Limosani, A.; Lincoln, D.; Linnemann, J.; Lipaev, V. V.; Lipeles, E.; Lipton, R.; Lister, A.; Liu, H.; Liu, Q.; Liu, T.; Liu, Y.; Lobodenko, A.; Lockwitz, S.; Loginov, A.; Lokajicek, M.; Lopes de Sa, R.; Lucchesi, D.; Lucà, A.; Lueck, J.; Lujan, P.; Lukens, P.; Luna-Garcia, R.; Lungu, G.; Lyon, A. L.; Lys, J.; Lysak, R.; Maciel, A. K. A.; Madar, R.; Madrak, R.; Maestro, P.; Magaña-Villalba, R.; Malik, S.; Malik, S.; Malyshev, V. L.; Manca, G.; Manousakis-Katsikakis, A.; Mansour, J.; Marchese, L.; Margaroli, F.; Marino, P.; Martínez-Ortega, J.; Matera, K.; Mattson, M. E.; Mazzacane, A.; Mazzanti, P.; McCarthy, R.; McGivern, C. L.; McNulty, R.; Mehta, A.; Mehtala, P.; Meijer, M. M.; Melnitchouk, A.; Menezes, D.; Mercadante, P. G.; Merkin, M.; Mesropian, C.; Meyer, A.; Meyer, J.; Miao, T.; Miconi, F.; Mietlicki, D.; Mitra, A.; Miyake, H.; Moed, S.; Moggi, N.; Mondal, N. K.; Moon, C. S.; Moore, R.; Morello, M. J.; Mukherjee, A.; Mulhearn, M.; Muller, Th.; Murat, P.; Mussini, M.; Nachtman, J.; Nagai, Y.; Naganoma, J.; Nagy, E.; Nakano, I.; Napier, A.; Narain, M.; Nayyar, R.; Neal, H. A.; Negret, J. P.; Nett, J.; Neustroev, P.; Nguyen, H. T.; Nigmanov, T.; Nodulman, L.; Noh, S. Y.; Norniella, O.; Nunnemann, T.; Oakes, L.; Oh, S. H.; Oh, Y. D.; Okusawa, T.; Orava, R.; Orduna, J.; Ortolan, L.; Osman, N.; Pagliarone, C.; Pal, A.; Palencia, E.; Palni, P.; Papadimitriou, V.; Parashar, N.; Parihar, V.; Park, S. K.; Parker, W.; Partridge, R.; Parua, N.; Patwa, A.; Pauletta, G.; Paulini, M.; Paus, C.; Penning, B.; Perfilov, M.; Peters, Y.; Petridis, K.; Petrillo, G.; Pétroff, P.; Phillips, T. J.; Piacentino, G.; Pianori, E.; Pilot, J.; Pitts, K.; Plager, C.; Pleier, M.-A.; Podstavkov, V. M.; Pondrom, L.; Popov, A. V.; Poprocki, S.; Potamianos, K.; Pranko, A.; Prewitt, M.; Price, D.; Prokopenko, N.; Prokoshin, F.; Ptohos, F.; Punzi, G.; Qian, J.; Quadt, A.; Quinn, B.; Ratoff, P. N.; Razumov, I.; Redondo Fernández, I.; Renton, P.; Rescigno, M.; Rimondi, F.; Ripp-Baudot, I.; Ristori, L.; Rizatdinova, F.; Robson, A.; Rodriguez, T.; Rolli, S.; Rominsky, M.; Ronzani, M.; Roser, R.; Rosner, J. L.; Ross, A.; Royon, C.; Rubinov, P.; Ruchti, R.; Ruffini, F.; Ruiz, A.; Russ, J.; Rusu, V.; Sajot, G.; Sakumoto, W. K.; Sakurai, Y.; Sánchez-Hernández, A.; Sanders, M. P.; Santi, L.; Santos, A. S.; Sato, K.; Savage, G.; Saveliev, V.; Savitskyi, M.; Savoy-Navarro, A.; Sawyer, L.; Scanlon, T.; Schamberger, R. D.; Scheglov, Y.; Schellman, H.; Schlabach, P.; Schmidt, E. E.; Schott, M.; Schwanenberger, C.; Schwarz, T.; Schwienhorst, R.; Scodellaro, L.; Scuri, F.; Seidel, S.; Seiya, Y.; Sekaric, J.; Semenov, A.; Severini, H.; Sforza, F.; Shabalina, E.; Shalhout, S. Z.; Shary, V.; Shaw, S.; Shchukin, A. A.; Shears, T.; Shepard, P. F.; Shimojima, M.; Shkola, O.; Shochet, M.; Shreyber-Tecker, I.; Simak, V.; Simonenko, A.; Skubic, P.; Slattery, P.; Sliwa, K.; Smith, J. R.; Snider, F. D.; Snow, G. R.; Snow, J.; Snyder, S.; Söldner-Rembold, S.; Song, H.; Sonnenschein, L.; Sorin, V.; Soustruznik, K.; St. Denis, R.; Stancari, M.; Stark, J.; Stefaniuk, N.; Stentz, D.; Stoyanova, D. A.; Strauss, M.; Strologas, J.; Sudo, Y.; Sukhanov, A.; Suslov, I.; Suter, L.; Svoisky, P.; Takemasa, K.; Takeuchi, Y.; Tang, J.; Tecchio, M.; Teng, P. K.; Thom, J.; Thomson, E.; Thukral, V.; Titov, M.; Toback, D.; Tokar, S.; Tokmenin, V. V.; Tollefson, K.; Tomura, T.; Tonelli, D.; Torre, S.; Torretta, D.; Totaro, P.; Trovato, M.; Tsai, Y.-T.; Tsybychev, D.; Tuchming, B.; Tully, C.; Ukegawa, F.; Uozumi, S.; Uvarov, L.; Uvarov, S.; Uzunyan, S.; Van Kooten, R.; van Leeuwen, W. M.; Varelas, N.; Varnes, E. W.; Vasilyev, I. A.; Vázquez, F.; Velev, G.; Vellidis, C.; Verkheev, A. Y.; Vernieri, C.; Vertogradov, L. S.; Verzocchi, M.; Vesterinen, M.; Vidal, M.; Vilanova, D.; Vilar, R.; Vizán, J.; Vogel, M.; Vokac, P.; Volpi, G.; Wagner, P.; Wahl, H. D.; Wallny, R.; Wang, M. H. L. S.; Wang, S. M.; Warchol, J.; Waters, D.; Watts, G.; Wayne, M.; Weichert, J.; Welty-Rieger, L.; Wester, W. C.; Whiteson, D.; Wicklund, A. B.; Wilbur, S.; Williams, H. H.; Williams, M. R. J.; Wilson, G. W.; Wilson, J. S.; Wilson, P.; Winer, B. L.; Wittich, P.; Wobisch, M.; Wolbers, S.; Wolfmeister, H.; Wood, D. R.; Wright, T.; Wu, X.; Wu, Z.; Wyatt, T. R.; Xie, Y.; Yamada, R.; Yamamoto, K.; Yamato, D.; Yang, S.; Yang, T.; Yang, U. K.; Yang, Y. C.; Yao, W.-M.; Yasuda, T.; Yatsunenko, Y. A.; Ye, W.; Ye, Z.; Yeh, G. P.; Yi, K.; Yin, H.; Yip, K.; Yoh, J.; Yorita, K.; Yoshida, T.; Youn, S. W.; Yu, G. B.; Yu, I.; Yu, J. M.; Zanetti, A. M.; Zeng, Y.; Zennamo, J.; Zhao, T. G.; Zhou, B.; Zhou, C.; Zhu, J.; Zielinski, M.; Zieminska, D.; Zivkovic, L.; Zucchelli, S.; CDF Collaboration

2018-01-01

The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of √{s }=1.96 TeV . We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is AFBt t ¯=0.128 ±0.025 . The combined inclusive and differential asymmetries are consistent with recent standard model predictions.

Combined Forward-Backward Asymmetry Measurements in Top-Antitop Quark Production at the Tevatron.

PubMed

Aaltonen, T; Abazov, V M; Abbott, B; Acharya, B S; Adams, M; Adams, T; Agnew, J P; Alexeev, G D; Alkhazov, G; Alton, A; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Appel, J A; Arisawa, T; Artikov, A; Asaadi, J; Ashmanskas, W; Askew, A; Atkins, S; Auerbach, B; Augsten, K; Aurisano, A; Aushev, V; Aushev, Y; Avila, C; Azfar, F; Badaud, F; Badgett, W; Bae, T; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, S; Barbaro-Galtieri, A; Barberis, E; Baringer, P; Barnes, V E; Barnett, B A; Barria, P; Bartlett, J F; Bartos, P; Bassler, U; Bauce, M; Bazterra, V; Bean, A; Bedeschi, F; Begalli, M; Behari, S; Bellantoni, L; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besançon, M; Beuselinck, R; Bhat, P C; Bhatia, S; Bhatnagar, V; Bhatti, A; Bland, K R; Blazey, G; Blessing, S; Bloom, K; Blumenfeld, B; Bocci, A; Bodek, A; Boehnlein, A; Boline, D; Boos, E E; Borissov, G; Bortoletto, D; Borysova, M; Boudreau, J; Boveia, A; 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de Jong, S J; De La Cruz-Burelo, E; Déliot, F; Demina, R; Demortier, L; Deninno, M; Denisov, D; Denisov, S P; D'Errico, M; Desai, S; Deterre, C; DeVaughan, K; Devoto, F; Di Canto, A; Di Ruzza, B; Diehl, H T; Diesburg, M; Ding, P F; Dittmann, J R; Dominguez, A; Donati, S; D'Onofrio, M; Dorigo, M; Driutti, A; Drutskoy, A; Dubey, A; Dudko, L V; Duperrin, A; Dutt, S; Eads, M; Ebina, K; Edgar, R; Edmunds, D; Elagin, A; Ellison, J; Elvira, V D; Enari, Y; Erbacher, R; Errede, S; Esham, B; Evans, H; Evdokimov, A; Evdokimov, V N; Farrington, S; Fauré, A; Feng, L; Ferbel, T; Fernández Ramos, J P; Fiedler, F; Field, R; Filthaut, F; Fisher, W; Fisk, H E; Flanagan, G; Forrest, R; Fortner, M; Fox, H; Franc, J; Franklin, M; Freeman, J C; Frisch, H; Fuess, S; Funakoshi, Y; Galloni, C; Garbincius, P H; Garcia-Bellido, A; García-González, J A; Garfinkel, A F; Garosi, P; Gavrilov, V; Geng, W; Gerber, C E; Gerberich, H; Gerchtein, E; Gershtein, Y; Giagu, S; Giakoumopoulou, V; Gibson, K; Ginsburg, C M; Ginther, G; 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Illingworth, R; Introzzi, G; Iori, M; Ito, A S; Ivanov, A; Jabeen, S; Jaffré, M; James, E; Jang, D; Jayasinghe, A; Jayatilaka, B; Jeon, E J; Jeong, M S; Jesik, R; Jiang, P; Jindariani, S; Johns, K; Johnson, E; Johnson, M; Jonckheere, A; Jones, M; Jonsson, P; Joo, K K; Joshi, J; Jun, S Y; Jung, A W; Junk, T R; Juste, A; Kajfasz, E; Kambeitz, M; Kamon, T; Karchin, P E; Karmanov, D; Kasmi, A; Kato, Y; Katsanos, I; Kaur, M; Kehoe, R; Kermiche, S; Ketchum, W; Keung, J; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Y N; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S H; Kim, S B; Kim, Y J; Kim, Y K; Kimura, N; Kirby, M; Kiselevich, I; Kohli, J M; Kondo, K; Kong, D J; Konigsberg, J; Kotwal, A V; Kozelov, A V; Kraus, J; Kreps, M; Kroll, J; Kruse, M; Kuhr, T; Kumar, A; Kupco, A; Kurata, M; Kurča, T; Kuzmin, V A; Laasanen, A T; Lammel, S; Lammers, S; Lancaster, M; Lannon, K; Latino, G; Lebrun, P; Lee, H S; Lee, H S; Lee, J S; Lee, S W; Lee, W M; Lei, X; Lellouch, J; Leo, S; Leone, S; Lewis, J D; Li, D; Li, H; Li, L; Li, Q Z; Lim, J K; Limosani, A; Lincoln, D; Linnemann, J; Lipaev, V V; Lipeles, E; Lipton, R; Lister, A; Liu, H; Liu, Q; Liu, T; Liu, Y; Lobodenko, A; Lockwitz, S; Loginov, A; Lokajicek, M; Lopes de Sa, R; Lucchesi, D; Lucà, A; Lueck, J; Lujan, P; Lukens, P; Luna-Garcia, R; Lungu, G; Lyon, A L; Lys, J; Lysak, R; Maciel, A K A; Madar, R; Madrak, R; Maestro, P; Magaña-Villalba, R; Malik, S; Malik, S; Malyshev, V L; Manca, G; Manousakis-Katsikakis, A; Mansour, J; Marchese, L; Margaroli, F; Marino, P; Martínez-Ortega, J; Matera, K; Mattson, M E; Mazzacane, A; Mazzanti, P; McCarthy, R; McGivern, C L; McNulty, R; Mehta, A; Mehtala, P; Meijer, M M; Melnitchouk, A; Menezes, D; Mercadante, P G; Merkin, M; Mesropian, C; Meyer, A; Meyer, J; Miao, T; Miconi, F; Mietlicki, D; Mitra, A; Miyake, H; Moed, S; Moggi, N; Mondal, N K; Moon, C S; Moore, R; Morello, M J; Mukherjee, A; Mulhearn, M; Muller, Th; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Naganoma, J; Nagy, E; Nakano, I; Napier, A; Narain, M; Nayyar, R; Neal, H A; Negret, J P; Nett, J; Neustroev, P; Nguyen, H T; Nigmanov, T; Nodulman, L; Noh, S Y; Norniella, O; Nunnemann, T; Oakes, L; Oh, S H; Oh, Y D; Okusawa, T; Orava, R; Orduna, J; Ortolan, L; Osman, N; Pagliarone, C; Pal, A; Palencia, E; Palni, P; Papadimitriou, V; Parashar, N; Parihar, V; Park, S K; Parker, W; Partridge, R; Parua, N; Patwa, A; Pauletta, G; Paulini, M; Paus, C; Penning, B; Perfilov, M; Peters, Y; Petridis, K; Petrillo, G; Pétroff, P; Phillips, T J; Piacentino, G; Pianori, E; Pilot, J; Pitts, K; Plager, C; Pleier, M-A; Podstavkov, V M; Pondrom, L; Popov, A V; Poprocki, S; Potamianos, K; Pranko, A; Prewitt, M; Price, D; Prokopenko, N; Prokoshin, F; Ptohos, F; Punzi, G; Qian, J; Quadt, A; Quinn, B; Ratoff, P N; Razumov, I; Redondo Fernández, I; Renton, P; Rescigno, M; Rimondi, F; Ripp-Baudot, I; Ristori, L; Rizatdinova, F; Robson, A; Rodriguez, T; Rolli, S; Rominsky, M; Ronzani, M; Roser, R; Rosner, J L; Ross, A; Royon, C; Rubinov, P; Ruchti, R; Ruffini, F; Ruiz, A; Russ, J; Rusu, V; Sajot, G; Sakumoto, W K; Sakurai, Y; Sánchez-Hernández, A; Sanders, M P; Santi, L; Santos, A S; Sato, K; Savage, G; Saveliev, V; Savitskyi, M; Savoy-Navarro, A; Sawyer, L; Scanlon, T; Schamberger, R D; Scheglov, Y; Schellman, H; Schlabach, P; Schmidt, E E; Schott, M; Schwanenberger, C; Schwarz, T; Schwienhorst, R; Scodellaro, L; Scuri, F; Seidel, S; Seiya, Y; Sekaric, J; Semenov, A; Severini, H; Sforza, F; Shabalina, E; Shalhout, S Z; Shary, V; Shaw, S; Shchukin, A A; Shears, T; Shepard, P F; Shimojima, M; Shkola, O; Shochet, M; Shreyber-Tecker, I; Simak, V; Simonenko, A; Skubic, P; Slattery, P; Sliwa, K; Smith, J R; Snider, F D; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Song, H; Sonnenschein, L; Sorin, V; Soustruznik, K; St Denis, R; Stancari, M; Stark, J; Stefaniuk, N; Stentz, D; Stoyanova, D A; Strauss, M; Strologas, J; Sudo, Y; Sukhanov, A; Suslov, I; Suter, L; Svoisky, P; Takemasa, K; Takeuchi, Y; Tang, J; Tecchio, M; Teng, P K; Thom, J; Thomson, E; Thukral, V; Titov, M; Toback, D; Tokar, S; Tokmenin, V V; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Trovato, M; Tsai, Y-T; Tsybychev, D; Tuchming, B; Tully, C; Ukegawa, F; Uozumi, S; Uvarov, L; Uvarov, S; Uzunyan, S; Van Kooten, R; van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Vázquez, F; Velev, G; Vellidis, C; Verkheev, A Y; Vernieri, C; Vertogradov, L S; Verzocchi, M; Vesterinen, M; Vidal, M; Vilanova, D; Vilar, R; Vizán, J; Vogel, M; Vokac, P; Volpi, G; Wagner, P; Wahl, H D; Wallny, R; Wang, M H L S; Wang, S M; Warchol, J; Waters, D; Watts, G; Wayne, M; Weichert, J; Welty-Rieger, L; Wester, W C; Whiteson, D; Wicklund, A B; Wilbur, S; Williams, H H; Williams, M R J; Wilson, G W; Wilson, J S; Wilson, P; Winer, B L; Wittich, P; Wobisch, M; Wolbers, S; Wolfmeister, H; Wood, D R; Wright, T; Wu, X; Wu, Z; Wyatt, T R; Xie, Y; Yamada, R; Yamamoto, K; Yamato, D; Yang, S; Yang, T; Yang, U K; Yang, Y C; Yao, W-M; Yasuda, T; Yatsunenko, Y A; Ye, W; Ye, Z; Yeh, G P; Yi, K; Yin, H; Yip, K; Yoh, J; Yorita, K; Yoshida, T; Youn, S W; Yu, G B; Yu, I; Yu, J M; Zanetti, A M; Zeng, Y; Zennamo, J; Zhao, T G; Zhou, B; Zhou, C; Zhu, J; Zielinski, M; Zieminska, D; Zivkovic, L; Zucchelli, S

2018-01-26

The CDF and D0 experiments at the Fermilab Tevatron have measured the asymmetry between yields of forward- and backward-produced top and antitop quarks based on their rapidity difference and the asymmetry between their decay leptons. These measurements use the full data sets collected in proton-antiproton collisions at a center-of-mass energy of sqrt[s]=1.96  TeV. We report the results of combinations of the inclusive asymmetries and their differential dependencies on relevant kinematic quantities. The combined inclusive asymmetry is A_{FB}^{tt[over ¯]}=0.128±0.025. The combined inclusive and differential asymmetries are consistent with recent standard model predictions.

Diagnostic ability of macular ganglion cell asymmetry for glaucoma.

PubMed

Hwang, Young Hoon; Ahn, Sang Il; Ko, Sung Ju

2015-11-01

Using spectral-domain optical coherence tomography (OCT), this study aims to investigate the glaucoma diagnostic ability of macular ganglion cell asymmetry analysis. A cross-sectional study was conducted. This study was performed to investigate glaucoma diagnostic ability of macular ganglion cell asymmetry analysis in eyes with various degrees of glaucoma. We enrolled 181 healthy eyes and 265 glaucomatous eyes. Glaucomatous eyes were subdivided into pre-perimetric, early, moderate and advanced-to-severe glaucoma based on visual field test results. For each eye, macular ganglion cell-inner plexiform layer (GCIPL) thickness was measured using OCT. Average GCIPL thickness, GCIPL thicknesses in superior and inferior hemispheres, absolute difference in GCIPL thickness between superior and inferior hemispheres and GCIPL asymmetry index calculated as the absolute value of log10 (inferior hemisphere thickness/superior hemisphere thickness) were analysed. Areas under the receiver operating characteristics curves (AUCs) of GCIPL parameter were calculated and compared. All of the GCIPL parameters showed good glaucoma diagnostic ability (AUCs ≥ 0.817, P < 0.01). AUCs of average, superior and inferior GCIPL thickness increased as the severity of glaucoma increased. GCIPL thickness difference and asymmetry index showed the highest AUCs in early and moderate glaucoma and lower AUCs in pre-perimetric and advanced-to-severe glaucoma. GCIPL thickness difference and asymmetry index showed better glaucoma diagnostic ability than other GCIPL parameters only in early stage of glaucoma (P < 0.05); in other stages, these parameters had similar to or worse glaucoma diagnostic ability than other GCIPL parameters. Macular ganglion cell asymmetry analysis showed good glaucoma diagnostic ability, especially in early-stage glaucoma. However, it has limited usefulness in other stages of glaucoma. © 2015 Royal Australian and New Zealand College of Ophthalmologists.

Asymmetries for the Visual Expression and Perception of Speech

ERIC Educational Resources Information Center

Nicholls, Michael E. R.; Searle, Dara A.

2006-01-01

This study explored asymmetries for movement, expression and perception of visual speech. Sixteen dextral models were videoed as they articulated: "bat," "cat," "fat," and "sat." Measurements revealed that the right side of the mouth was opened wider and for a longer period than the left. The asymmetry was accentuated at the beginning and ends of…

Postural asymmetries in young adults with cerebral palsy.

PubMed

Rodby-Bousquet, Elisabet; Czuba, Tomasz; Hägglund, Gunnar; Westbom, Lena

2013-11-01

The purpose was to describe posture, ability to change position, and association between posture and contractures, hip dislocation, scoliosis, and pain in young adults with cerebral palsy (CP). Cross-sectional data of 102 people (63 males, 39 females; age range 19-23 y, median 21 y) out of a total population with CP was analysed in relation to Gross Motor Function Classification System (GMFCS) levels I (n=38), II (n=21), III (n=13), IV (n=10), and V (n=20). The CP subtypes were unilateral spastic (n=26), bilateral spastic (n=45), ataxic (n=12), and dyskinetic CP (n=19). The Postural Ability Scale was used to assess posture. The relationship between posture and joint range of motion, hip dislocation, scoliosis, and pain was analysed using logistic regression and Spearman's correlation. At GMFCS levels I to II, head and trunk asymmetries were most common; at GMFCS levels III to V postural asymmetries varied with position. The odds ratios (OR) for severe postural asymmetries were significantly higher for those with scoliosis (OR=33 sitting), limited hip extension (OR=39 supine), or limited knee extension (OR=37 standing). Postural asymmetries correlated to hip dislocations: supine (r(s) =0.48), sitting (r(s) =0.40), standing (r(s) =0.41), and inability to change position: supine (r(s) =0.60), sitting (r(s) =0.73), and standing (r(s) =0.64). Postural asymmetries were associated with scoliosis, hip dislocations, hip and knee contractures, and inability to change position. © 2013 The Authors. Developmental Medicine & Child Neurology published by John Wiley & Sons Ltd on behalf of Mac Keith Press.

The impact of surgical treatment on the self-esteem of patients with breast hypertrophy, hypomastia, or breast asymmetry.

PubMed

Neto, Miguel Sabino; Abla, Luiz Eduardo Felipe; Lemos, Ana Lucia; Garcia, Élvio Bueno; Enout, Mariana Junqueira Reis; Cabral, Nádia Canale; Ferreira, Lydia Masako

2012-02-01

Currently, the concept of health includes not only the absence of disease but also a complete state of physical, psychological, and social well-being with increased emphasis on the importance of self-esteem. This study aimed to evaluate the impact of surgical treatment on the self-esteem of patients with breast asymmetry, breast hypertrophy, or hypomastia. The Rosenberg Self-Esteem UNIFESP-EPM Scale was administered preoperatively and in the early and late postoperative periods to assess self-esteem. The sample comprised three groups of patients: the breast asymmetry group (n=35), the breast hypertrophy group (n=50), and the hypomastia group (n=40). Surgical treatment had a positive and similar impact on the self-esteem of the patients in the three study groups. Correction of breast asymmetry, breast hypertrophy, and hypomastia improved the patient's self-esteem. All three groups reported a similar increase in self-esteem (decrease in total scores) after breast reconstruction.

Energy evolution for the Sivers asymmetries in hard processes

NASA Astrophysics Data System (ADS)

Sun, Peng; Yuan, Feng

2013-08-01

We investigate the energy evolution of the azimuthal spin asymmetries in semi-inclusive hadron production in deep inelastic scattering (SIDIS) and Drell-Yan lepton pair production in pp collisions. The scale dependence is evaluated by applying an approximate solution to the Collins-Soper-Sterman evolution equation at one-loop order, which is adequate for moderate Q2 variations. This describes well the unpolarized cross sections for the SIDIS and Drell-Yan process in the Q2 range of 2.4-100GeV2. A combined analysis of the Sivers asymmetries in SIDIS from HERMES and COMPASS experiments and the predictions for the Drell-Yan process at RHIC at S=200GeV are presented. We further extend to the Collins asymmetries and find, for the first time, a consistent description for HERMES/COMPASS and BELLE experiments with the evolution effects. We emphasize an important test of the evolution effects by studying di-hadron azimuthal asymmetry in e+e- annihilation at moderate energy range, such as at BEPC at S=4.6GeV.

Nonlinear growth dynamics and the origin of fluctuating asymmetry

USGS Publications Warehouse

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

1993-01-01

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

Foot force production and asymmetries in elite rowers.

PubMed

Buckeridge, Erica M; Bull, Anthony M J; McGregor, Alison H

2014-03-01

The rowing stroke is a leg-driven action, in which forces developed by the lower limbs provide a large proportion of power delivered to the oars. In terms of both performance and injury, it is important to initiate each stroke with powerful and symmetrical loading of the foot stretchers. The aims of this study were to assess the reliability of foot force measured by footplates developed for the Concept2 indoor ergometer and to examine the magnitude and symmetry of bilateral foot forces in different groups of rowers. Five heavyweight female scullers, six heavyweight female sweep rowers, and six lightweight male (LWM) rowers performed an incremental step test on the Concept2 ergometer. Vertical, horizontal, and resultant forces were recorded bilaterally, and asymmetries were quantified using the absolute symmetry index. Foot force was measured with high consistency (coefficient of multiple determination > 0.976 +/- 0.010). Relative resultant, vertical, and horizontal forces were largest in LWM rowers, whilst average foot forces significantly increased across stroke rates for all three groups of rowers. Asymmetries ranged from 5.3% for average resultant force to 28.9% for timing of peak vertical force. Asymmetries were not sensitive to stroke rate or rowing group, however, large inter-subject variability in asymmetries was evident.

Investors’ risk attitudes and stock price fluctuation asymmetry

NASA Astrophysics Data System (ADS)

Zhang, Yu; Li, Honggang

2011-05-01

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

Genetic basis of human left-right asymmetry disorders.

PubMed

Deng, Hao; Xia, Hong; Deng, Sheng

2015-01-27

Humans and other vertebrates exhibit left-right (LR) asymmetric arrangement of the internal organs, and failure to establish normal LR asymmetry leads to internal laterality disorders, including situs inversus and heterotaxy. Situs inversus is complete mirror-imaged arrangement of the internal organs along LR axis, whereas heterotaxy is abnormal arrangement of the internal thoraco-abdominal organs across LR axis of the body, most of which are associated with complex cardiovascular malformations. Both disorders are genetically heterogeneous with reduced penetrance, presumably because of monogenic, polygenic or multifactorial causes. Research in genetics of LR asymmetry disorders has been extremely prolific over the past 17 years, and a series of loci and disease genes involved in situs inversus and heterotaxy have been described. The review highlights the classification, chromosomal abnormalities, pathogenic genes and the possible mechanism of human LR asymmetry disorders.

Influence of trait behavioral inhibition and behavioral approach motivation systems on the LPP and frontal asymmetry to anger pictures.

PubMed