Sample records for coupled pair functional

  1. Generalized valence bond description of the ground states (X(1)Σg(+)) of homonuclear pnictogen diatomic molecules: N2, P2, and As2.

    PubMed

    Xu, Lu T; Dunning, Thom H

    2015-06-09

    The ground state, X1Σg+, of N2 is a textbook example of a molecule with a triple bond consisting of one σ and two π bonds. This assignment, which is usually rationalized using molecular orbital (MO) theory, implicitly assumes that the spins of the three pairs of electrons involved in the bonds are singlet-coupled (perfect pairing). However, for a six-electron singlet state, there are five distinct ways to couple the electron spins. The generalized valence bond (GVB) wave function lifts this restriction, including all of the five spin functions for the six electrons involved in the bond. For N2, we find that the perfect pairing spin function is indeed dominant at Re but that it becomes progressively less so from N2 to P2 and As2. Although the perfect pairing spin function is still the most important spin function in P2, the importance of a quasi-atomic spin function, which singlet couples the spins of the electrons in the σ orbitals while high spin coupling those of the electrons in the π orbitals on each center, has significantly increased relative to N2 and, in As2, the perfect pairing and quasi-atomic spin couplings are on essentially the same footing. This change in the spin coupling of the electrons in the bonding orbitals down the periodic table may contribute to the rather dramatic decrease in the strengths of the Pn2 bonds from N2 to As2 as well as in the increase in their chemical reactivity and should be taken into account in more detailed analyses of the bond energies in these species. We also compare the spin coupling in N2 with that in C2, where the quasi-atomic spin coupling dominants around Re.

  2. Role of the Pair Correlation Function in the Dynamical Transition Predicted by Mode Coupling Theory

    NASA Astrophysics Data System (ADS)

    Nandi, Manoj Kumar; Banerjee, Atreyee; Dasgupta, Chandan; Bhattacharyya, Sarika Maitra

    2017-12-01

    In a recent study, we have found that for a large number of systems the configurational entropy at the pair level Sc 2, which is primarily determined by the pair correlation function, vanishes at the dynamical transition temperature Tc. Thus, it appears that the information of the transition temperature is embedded in the structure of the liquid. In order to investigate this, we describe the dynamics of the system at the mean field level and, using the concepts of the dynamical density functional theory, show that the dynamical transition temperature depends only on the pair correlation function. Thus, this theory is similar in spirit to the microscopic mode coupling theory (MCT). However, unlike microscopic MCT, which predicts a very high transition temperature, the present theory predicts a transition temperature that is similar to Tc. This implies that the information of the dynamical transition temperature is embedded in the pair correlation function.

  3. Couples, Pairs, and Clusters: Mechanisms and Implications of Centromere Associations in Meiosis

    PubMed Central

    Obeso, David; Pezza, Roberto J; Dawson, Dean

    2013-01-01

    Observations from a wide range of organisms show the centromeres form associations of pairs or small groups at different stages of meiotic prophase. Little is known about the functions or mechanisms of these associations, but in many cases synaptonemal complex elements seem to play a fundamental role. Two main associations are observed: homology-independent associations very early in the meiotic program – sometimes referred to as centromere coupling, and a later association of homologous centromeres, referred to as centromere pairing or tethering. The later centromere pairing initiates during synaptonemal complex assembly, then persists after the dissolution of the synaptonemal complex. While the function of the homology-independent centromere coupling remains a mystery, centromere pairing appears to have a direct impact on the chromosome segregation fidelity of achiasmatic chromosomes. Recent work in yeast, Drosophila, and mice suggest centromere pairing is a previously unappreciated, general meiotic feature that may promote meiotic segregation fidelity of the exchange and non-exchange chromosomes. PMID:24126501

  4. Couples, pairs, and clusters: mechanisms and implications of centromere associations in meiosis.

    PubMed

    Obeso, David; Pezza, Roberto J; Dawson, Dean

    2014-03-01

    Observations of a wide range of organisms show that the centromeres form associations of pairs or small groups at different stages of meiotic prophase. Little is known about the functions or mechanisms of these associations, but in many cases, synaptonemal complex elements seem to play a fundamental role. Two main associations are observed: homology-independent associations very early in the meiotic program-sometimes referred to as centromere coupling-and a later association of homologous centromeres, referred to as centromere pairing or tethering. The later centromere pairing initiates during synaptonemal complex assembly, then persists after the dissolution of the synaptonemal complex. While the function of the homology-independent centromere coupling remains a mystery, centromere pairing appears to have a direct impact on the chromosome segregation fidelity of achiasmatic chromosomes. Recent work in yeast, Drosophila, and mice suggest that centromere pairing is a previously unappreciated, general meiotic feature that may promote meiotic segregation fidelity of the exchange and non-exchange chromosomes.

  5. Role of the Pair Correlation Function in the Dynamical Transition Predicted by Mode Coupling Theory.

    PubMed

    Nandi, Manoj Kumar; Banerjee, Atreyee; Dasgupta, Chandan; Bhattacharyya, Sarika Maitra

    2017-12-29

    In a recent study, we have found that for a large number of systems the configurational entropy at the pair level S_{c2}, which is primarily determined by the pair correlation function, vanishes at the dynamical transition temperature T_{c}. Thus, it appears that the information of the transition temperature is embedded in the structure of the liquid. In order to investigate this, we describe the dynamics of the system at the mean field level and, using the concepts of the dynamical density functional theory, show that the dynamical transition temperature depends only on the pair correlation function. Thus, this theory is similar in spirit to the microscopic mode coupling theory (MCT). However, unlike microscopic MCT, which predicts a very high transition temperature, the present theory predicts a transition temperature that is similar to T_{c}. This implies that the information of the dynamical transition temperature is embedded in the pair correlation function.

  6. Strongly exchange-coupled triplet pairs in an organic semiconductor

    NASA Astrophysics Data System (ADS)

    Weiss, Leah R.; Bayliss, Sam L.; Kraffert, Felix; Thorley, Karl J.; Anthony, John E.; Bittl, Robert; Friend, Richard H.; Rao, Akshay; Greenham, Neil C.; Behrends, Jan

    2017-02-01

    From biological complexes to devices based on organic semiconductors, spin interactions play a key role in the function of molecular systems. For instance, triplet-pair reactions impact operation of organic light-emitting diodes as well as photovoltaic devices. Conventional models for triplet pairs assume they interact only weakly. Here, using electron spin resonance, we observe long-lived, strongly interacting triplet pairs in an organic semiconductor, generated via singlet fission. Using coherent spin manipulation of these two-triplet states, we identify exchange-coupled (spin-2) quintet complexes coexisting with weakly coupled (spin-1) triplets. We measure strongly coupled pairs with a lifetime approaching 3 μs and a spin coherence time approaching 1 μs, at 10 K. Our results pave the way for the utilization of high-spin systems in organic semiconductors.

  7. Micromagnetic simulations of anisotropies in coupled and uncoupled ferromagnetic nanowire systems.

    PubMed

    Blachowicz, T; Ehrmann, A

    2013-01-01

    The influence of a variation of spatial relative orientations onto the coupling dynamics and subsequent magnetic anisotropies was modeled in ferromagnetic nanowires. The wires were analyzed in the most elementary configurations, thus, arranged in pairs perpendicular to each other, leading to one-dimensional (linear) and zero-dimensional (point-like) coupling. Different distances within each elementary pair of wires and between the pairs give rise to varying interactions between parallel and perpendicular wires, respectively. Simulated coercivities show an exchange of easy and hard axes for systems with different couplings. Additionally, two of the systems exhibit a unique switching behavior which can be utilized for developing new functionalities.

  8. Crossover from BCS to Bose superconductivity: A functional integral approach

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

    Randeria, M.; Sa de Melo, C.A.R.; Engelbrecht, J.R.

    1993-04-01

    We use a functional integral formulation to study the crossover from cooperative Cooper pairing to the formation and condensation of tightly bound pairs in a 3D continuum model of fermions with attractive interactions. The inadequacy of a saddle point approximation with increasing coupling is pointed out, and the importance of temporal (quantum) fluctuations for normal state properties at intermediate and strong coupling is emphasized. In addition to recovering the Nozieres-Schmitt-Pink interpolation scheme for T{sub c}, and the Leggett variational results for T = 0, we also present results for evolution of the time-dependent Ginzburg-Landau equation and collective mode spectrum asmore » a function of the coupling.« less

  9. Resonance coupling and polarization conversion in terahertz metasurfaces with twisted split-ring resonator pairs

    DOE PAGES

    Li, Chenyu; Chang, Chun-Chieh; Zhou, Qingli; ...

    2017-10-10

    Here, we investigate edge-coupling of twisted split-ring resonator (SRR) pairs in the terahertz (THz) frequency range. By using a simple coupled-resonator model we show that such a system exhibits resonance splitting and cross-polarization conversion. Numerical simulations and experimental measurements agree well with theoretical calculations, verifying the resonance splitting as a function of the coupling strength given by the SRR separation. We further show that a metal ground plane can be integrated to significantly enhance the resonance coupling, which enables the effective control of resonance splitting and the efficiency and bandwidth of the cross-polarization conversion. Our findings improve the fundamental understandingmore » of metamaterials with a view of accomplishing metamaterial functionalities with enhanced performance, which is of great interest in realizing THz functional devices required in a variety of applications.« less

  10. The effect of movement and load on the dynamic coupling of abdominal electromyography.

    PubMed

    King, Adam C

    2018-05-14

    This study investigated the degree of neural coupling in abdominal muscle activity and whether the task constraints of movement and load altered the coupling within three muscle pairings. Nineteen young, physically-active individuals performed sit-up and reverse crunch movements in bodyweight (BW) and loaded (+4.54 kg) conditions. Surface electromyography (sEMG) was recorded from the rectus abdominus (RA), external oblique (EO), and transverse abdominus (TA) muscles. Linear (correlation coefficient) and non-linear (Cross-Approximate Entropy) measurements evaluated the degree of couplings across three muscle pairings. Compared to a resting coupling state, most conditions showed evidence of coupling. The linear coupling showed greater coupling compared to the resting state. Dynamic coupling showed lower degrees of coupling for the RA-EO and RA-TA pairings but stronger coupling for the EO-TA pairing with the sit-up movement exhibiting lower Cross-ApEn (higher dynamic coupling) than the reverse crunch. The results provide preliminary evidence of coupling in abdominal muscle activity that was influenced by movement, but not load. The functional roles of the RA (prime mover), EO and TA (stabilizers) muscles may have influenced the degree of coupling and future investigations are needed to better understand the coupling of abdominal muscle activity. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. A comparison of the coupled cluster and internally contracted averaged coupled-pair functional levels of theory for the calculation of the MCH2(+) binding energies for M = Sc to Cu

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Partridge, Harry; Scuseria, Gustavo E.

    1992-01-01

    The correlation contribution to the M-C binding energy for the MCH2(+) systems can exceed 100 kcal/mol. At the self-consistent field (SCF) level, these systems can be more than 50 kcal/mol above the fragment energies. In spite of the poor zeroth-order reference, the coupled cluster single and double excitation method with a perturbational estimate of triple excitations, CCSD(T), method is shown to provide an accurate description of these systems. The maximum difference between the CCSD(T) and internally contracted averaged coupled-pair functional binding energies is 1.5 kcal/mol for CrCH2(+), with the remaining systems agreeing to within 1.0 kcal/mol.

  12. Tunneling of coupled methyl quantum rotors in 4-methylpyridine: Single rotor potential versus coupling interaction

    NASA Astrophysics Data System (ADS)

    Khazaei, Somayeh; Sebastiani, Daniel

    2017-11-01

    We study the influence of rotational coupling between a pair of methyl rotators on the tunneling spectrum in condensed phase. Two interacting adjacent methyl groups are simulated within a coupled-pair model composed of static rotational potential created by the chemical environment and the interaction potential between two methyl groups. We solve the two-dimensional time-independent Schrödinger equation analytically by expanding the wave functions on the basis set of two independent free-rotor functions. We investigate three scenarios which differ with respect to the relative strength of single-rotor and coupling potential. For each scenario, we illustrate the dependence of the energy level scheme on the coupling strength. It is found that the main determinant of splitting energy levels tends to be a function of the ratio of strengths of coupling and single-rotor potential. The tunnel splitting caused by coupling is maximized for the coupled rotors in which their total hindering potential is relatively shallow. Such a weakly hindered methyl rotational potential is predicted for 4-methylpyridine at low temperature. The experimental observation of multiple tunneling peaks arising from a single type of methyl group in 4-methylpyridine in the inelastic neutron scattering spectrum is widely attributed to the rotor-rotor coupling. In this regard, using a set of first-principles calculations combined with the nudged elastic band method, we investigate the rotational potential energy surface (PES) of the coaxial pairs of rotors in 4-methylpyridine. A Numerov-type method is used to numerically solve the two-dimensional time-independent Schrödinger equation for the calculated 2D-density functional theory profile. Our computed energy levels reproduce the observed tunneling transitions well. Moreover, the calculated density distribution of the three methyl protons resembles the experimental nuclear densities obtained from the Fourier difference method. By mapping the calculated first-principles PES on the model, it is confirmed that the hindering potential in 4-methylpyridine consists of proportionally shallow single-rotor potential to coupling interaction.

  13. Tunneling of coupled methyl quantum rotors in 4-methylpyridine: Single rotor potential versus coupling interaction.

    PubMed

    Khazaei, Somayeh; Sebastiani, Daniel

    2017-11-21

    We study the influence of rotational coupling between a pair of methyl rotators on the tunneling spectrum in condensed phase. Two interacting adjacent methyl groups are simulated within a coupled-pair model composed of static rotational potential created by the chemical environment and the interaction potential between two methyl groups. We solve the two-dimensional time-independent Schrödinger equation analytically by expanding the wave functions on the basis set of two independent free-rotor functions. We investigate three scenarios which differ with respect to the relative strength of single-rotor and coupling potential. For each scenario, we illustrate the dependence of the energy level scheme on the coupling strength. It is found that the main determinant of splitting energy levels tends to be a function of the ratio of strengths of coupling and single-rotor potential. The tunnel splitting caused by coupling is maximized for the coupled rotors in which their total hindering potential is relatively shallow. Such a weakly hindered methyl rotational potential is predicted for 4-methylpyridine at low temperature. The experimental observation of multiple tunneling peaks arising from a single type of methyl group in 4-methylpyridine in the inelastic neutron scattering spectrum is widely attributed to the rotor-rotor coupling. In this regard, using a set of first-principles calculations combined with the nudged elastic band method, we investigate the rotational potential energy surface (PES) of the coaxial pairs of rotors in 4-methylpyridine. A Numerov-type method is used to numerically solve the two-dimensional time-independent Schrödinger equation for the calculated 2D-density functional theory profile. Our computed energy levels reproduce the observed tunneling transitions well. Moreover, the calculated density distribution of the three methyl protons resembles the experimental nuclear densities obtained from the Fourier difference method. By mapping the calculated first-principles PES on the model, it is confirmed that the hindering potential in 4-methylpyridine consists of proportionally shallow single-rotor potential to coupling interaction.

  14. Evolution from BCS superconductivity to Bose condensation: Calculation of the zero-temperature phase coherence length

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

    Pistolesi, F.; Strinati, G.C.

    1996-06-01

    We consider a fermionic system at zero temperature interacting through an effective nonretarded potential of the type introduced by Nozi{grave e}res and Schmitt-Rink, and calculate the {ital phase} coherence length {xi}{sub phase} (associated with the spatial fluctuations of the superconducting order parameter) by exploiting a functional-integral formulation for the correlation functions and the associated loop expansion. This formulation is especially suited to follow the evolution of the fermionic system from a BCS-type superconductor for weak coupling to a Bose-condensed system for strong coupling, since in the latter limit a {ital direct} mapping of the original fermionic system onto an effectivemore » system of bosons with a residual boson-boson interaction can be established. Explicit calculations are performed at the one-loop order. The phase coherence length {xi}{sub phase} is compared with the coherence length {xi}{sub pair} for two-electron correlation, which is relevant to distinguish the weak- ({ital k}{sub {ital F}}{xi}{sub pair}{gt}1) from the strong- ({ital k}{sub {ital F}}{xi}{sub pair}{lt}1) coupling limits ({ital k}{sub {ital F}} being the Fermi wave vector) {ital as} {ital well} {ital as} to follow the crossover in between. It is shown that {xi}{sub phase} coincides with {xi}{sub pair} down to {ital k}{sub {ital F}}{xi}{sub pair}{approx_equal}10, {xi}{sub pair} in turn coinciding with the Pippard coherence length. In the strong-coupling limit we find instead that {xi}{sub phase}{gt}{xi}{sub pair}, with {xi}{sub pair} coinciding with the radius of the bound-electron pair. From the mapping onto an effective system of bosons in the strong-coupling limit we further relate {xi}{sub pair} with the {open_quote}{open_quote}range{close_quote}{close_quote} of the residual boson-boson interaction, which is physically the only significant length associated with the dynamics of the bosonic system. {copyright} {ital 1996 The American Physical Society.}« less

  15. Resolving the degeneracy in single Higgs production with Higgs pair production

    NASA Astrophysics Data System (ADS)

    Cao, Qing-Hong; Yan, Bin; Zhang, Dong-Ming; Zhang, Hao

    2016-01-01

    The Higgs boson production can be affected by several anomalous couplings, e.g. ct and cg anomalous couplings. Precise measurement of gg → h production yields two degenerate parameter spaces of ct and cg; one parameter space exhibits the SM limit while the other does not. Such a degeneracy could be resolved by Higgs boson pair production. In this work we adapt the strategy suggested by the ATLAS collaboration to explore the potential of distinguishing the degeneracy at the 14 TeV LHC. If the ct anomalous coupling is induced only by the operator H† HQbarL H ˜ tR, then the non-SM-like band could be excluded with an integrated luminosity of ∼ 210 fb-1. Making use of the fact that the Higgs boson pair is mainly produced through an s-wave scattering, we propose an analytical function to describe the fraction of signal events surviving a series of experimental cuts for a given invariant mass of Higgs boson pair. The function is model independent and can be applied to estimate the discovery potential of various NP models.

  16. Resolving the degeneracy in single Higgs production with Higgs pair production

    DOE PAGES

    Cao, Qing -Hong; Yan, Bin; Zhang, Dong -Ming; ...

    2015-11-28

    The Higgs boson production can be affected by several anomalous couplings, e.g. ct and cg anomalous couplings. Precise measurement of gg → h production yields two degenerate parameter spaces of ct and cg; one parameter space exhibits the SM limit while the other does not. Such a degeneracy could be resolved by Higgs boson pair production. In this work we adapt the strategy suggested by the ATLAS collaboration to explore the potential of distinguishing the degeneracy at the 14 TeV LHC. If the ct anomalous coupling is induced only by the operator H↑HQ¯ LH ~t R, then the non-SM-like bandmore » could be excluded with an integrated luminosity of ~235 fb –1. Making use of the fact that the Higgs boson pair is mainly produced through an s-wave scattering, we propose an analytical function to describe the fraction of signal events surviving a series of experimental cuts for a given invariant mass of Higgs boson pair. As a result, the function is model independent and can be applied to estimate the discovery potential of various NP models.« less

  17. [Paired kidneys in transplant].

    PubMed

    Regueiro López, Juan C; Leva Vallejo, Manuel; Prieto Castro, Rafael; Anglada Curado, Francisco; Vela Jiménez, Francisco; Ruiz García, Jesús

    2009-02-01

    Many factors affect the graft and patient survival on the renal transplant outcome. These factors depend so much of the recipient and donor. We accomplished a study trying to circumvent factors that depend on the donor. We checked the paired kidneys originating of a same donor cadaver. We examined the risk factors in the evolution and follow-up in 278 couples of kidney transplant. We describe their differences, significance, the graft and patient survival, their functionality in 3 and 5 years and the risk factors implicated in their function. We study immunogenic and no immunogenic variables, trying to explain the inferior results in the grafts that are established secondly. We regroup the paired kidneys in those that they did not show paired initial function within the same couple. The results yield a discreet deterioration in the graft and patient survival for second group establish, superior creatinina concentration, without obtaining statistical significance. The Cox regression study establishes the early rejection (inferior to three months) and DR incompatibility values like risk factors. This model of paired kidneys would be able to get close to best-suited form for risk factors analysis in kidney transplant from cadaver donors, if more patients examine themselves in the same way. The paired kidneys originating from the same donor do not show the same function in spite of sharing the same conditions of the donor and perioperative management.

  18. Effects of hand configuration on muscle force coordination, co-contraction and concomitant intermuscular coupling during maximal isometric flexion of the fingers.

    PubMed

    Charissou, Camille; Amarantini, David; Baurès, Robin; Berton, Eric; Vigouroux, Laurent

    2017-11-01

    The mechanisms governing the control of musculoskeletal redundancy remain to be fully understood. The hand is highly redundant, and shows different functional role of extensors according to its configuration for a same functional task of finger flexion. Through intermuscular coherence analysis combined with hand musculoskeletal modelling during maximal isometric hand contractions, our aim was to better understand the neural mechanisms underlying the control of muscle force coordination and agonist-antagonist co-contraction. Thirteen participants performed maximal isometric flexions of the fingers in two configurations: power grip (Power) and finger-pressing on a surface (Press). Hand kinematics and force/moment measurements were used as inputs in a musculoskeletal model of the hand to determine muscular tensions and co-contraction. EMG-EMG coherence analysis was performed between wrist and finger flexors and extensor muscle pairs in alpha, beta and gamma frequency bands. Concomitantly with tailored muscle force coordination and increased co-contraction between Press and Power (mean difference: 48.08%; p < 0.05), our results showed muscle-pair-specific modulation of intermuscular coupling, characterized by pair-specific modulation of EMG-EMG coherence between Power and Press (p < 0.05), and a negative linear association between co-contraction and intermuscular coupling for the ECR/FCR agonist-antagonist muscle pair (r = - 0.65; p < 0.05). This study brings new evidence that pair-specific modulation of EMG-EMG coherence is related to modulation of muscle force coordination during hand contractions. Our results highlight the functional importance of intermuscular coupling as a mechanism contributing to the control of muscle force synergies and agonist-antagonist co-contraction.

  19. Efficient and accurate local approximations to coupled-electron pair approaches: An attempt to revive the pair natural orbital method

    NASA Astrophysics Data System (ADS)

    Neese, Frank; Wennmohs, Frank; Hansen, Andreas

    2009-03-01

    Coupled-electron pair approximations (CEPAs) and coupled-pair functionals (CPFs) have been popular in the 1970s and 1980s and have yielded excellent results for small molecules. Recently, interest in CEPA and CPF methods has been renewed. It has been shown that these methods lead to competitive thermochemical, kinetic, and structural predictions. They greatly surpass second order Møller-Plesset and popular density functional theory based approaches in accuracy and are intermediate in quality between CCSD and CCSD(T) in extended benchmark studies. In this work an efficient production level implementation of the closed shell CEPA and CPF methods is reported that can be applied to medium sized molecules in the range of 50-100 atoms and up to about 2000 basis functions. The internal space is spanned by localized internal orbitals. The external space is greatly compressed through the method of pair natural orbitals (PNOs) that was also introduced by the pioneers of the CEPA approaches. Our implementation also makes extended use of density fitting (or resolution of the identity) techniques in order to speed up the laborious integral transformations. The method is called local pair natural orbital CEPA (LPNO-CEPA) (LPNO-CPF). The implementation is centered around the concepts of electron pairs and matrix operations. Altogether three cutoff parameters are introduced that control the size of the significant pair list, the average number of PNOs per electron pair, and the number of contributing basis functions per PNO. With the conservatively chosen default values of these thresholds, the method recovers about 99.8% of the canonical correlation energy. This translates to absolute deviations from the canonical result of only a few kcal mol-1. Extended numerical test calculations demonstrate that LPNO-CEPA (LPNO-CPF) has essentially the same accuracy as parent CEPA (CPF) methods for thermochemistry, kinetics, weak interactions, and potential energy surfaces but is up to 500 times faster. The method performs best in conjunction with large and flexible basis sets. These results open the way for large-scale chemical applications.

  20. Efficient and accurate local approximations to coupled-electron pair approaches: An attempt to revive the pair natural orbital method.

    PubMed

    Neese, Frank; Wennmohs, Frank; Hansen, Andreas

    2009-03-21

    Coupled-electron pair approximations (CEPAs) and coupled-pair functionals (CPFs) have been popular in the 1970s and 1980s and have yielded excellent results for small molecules. Recently, interest in CEPA and CPF methods has been renewed. It has been shown that these methods lead to competitive thermochemical, kinetic, and structural predictions. They greatly surpass second order Moller-Plesset and popular density functional theory based approaches in accuracy and are intermediate in quality between CCSD and CCSD(T) in extended benchmark studies. In this work an efficient production level implementation of the closed shell CEPA and CPF methods is reported that can be applied to medium sized molecules in the range of 50-100 atoms and up to about 2000 basis functions. The internal space is spanned by localized internal orbitals. The external space is greatly compressed through the method of pair natural orbitals (PNOs) that was also introduced by the pioneers of the CEPA approaches. Our implementation also makes extended use of density fitting (or resolution of the identity) techniques in order to speed up the laborious integral transformations. The method is called local pair natural orbital CEPA (LPNO-CEPA) (LPNO-CPF). The implementation is centered around the concepts of electron pairs and matrix operations. Altogether three cutoff parameters are introduced that control the size of the significant pair list, the average number of PNOs per electron pair, and the number of contributing basis functions per PNO. With the conservatively chosen default values of these thresholds, the method recovers about 99.8% of the canonical correlation energy. This translates to absolute deviations from the canonical result of only a few kcal mol(-1). Extended numerical test calculations demonstrate that LPNO-CEPA (LPNO-CPF) has essentially the same accuracy as parent CEPA (CPF) methods for thermochemistry, kinetics, weak interactions, and potential energy surfaces but is up to 500 times faster. The method performs best in conjunction with large and flexible basis sets. These results open the way for large-scale chemical applications.

  1. Pair mobility functions for rigid spheres in concentrated colloidal dispersions: Stresslet and straining motion couplings

    NASA Astrophysics Data System (ADS)

    Su, Yu; Swan, James W.; Zia, Roseanna N.

    2017-03-01

    Accurate modeling of particle interactions arising from hydrodynamic, entropic, and other microscopic forces is essential to understanding and predicting particle motion and suspension behavior in complex and biological fluids. The long-range nature of hydrodynamic interactions can be particularly challenging to capture. In dilute dispersions, pair-level interactions are sufficient and can be modeled in detail by analytical relations derived by Jeffrey and Onishi [J. Fluid Mech. 139, 261-290 (1984)] and Jeffrey [Phys. Fluids A 4, 16-29 (1992)]. In more concentrated dispersions, analytical modeling of many-body hydrodynamic interactions quickly becomes intractable, leading to the development of simplified models. These include mean-field approaches that smear out particle-scale structure and essentially assume that long-range hydrodynamic interactions are screened by crowding, as particle mobility decays at high concentrations. Toward the development of an accurate and simplified model for the hydrodynamic interactions in concentrated suspensions, we recently computed a set of effective pair of hydrodynamic functions coupling particle motion to a hydrodynamic force and torque at volume fractions up to 50% utilizing accelerated Stokesian dynamics and a fast stochastic sampling technique [Zia et al., J. Chem. Phys. 143, 224901 (2015)]. We showed that the hydrodynamic mobility in suspensions of colloidal spheres is not screened, and the power law decay of the hydrodynamic functions persists at all concentrations studied. In the present work, we extend these mobility functions to include the couplings of particle motion and straining flow to the hydrodynamic stresslet. The couplings computed in these two articles constitute a set of orthogonal coupling functions that can be utilized to compute equilibrium properties in suspensions at arbitrary concentration and are readily applied to solve many-body hydrodynamic interactions analytically.

  2. Functional renormalization group study of orbital fluctuation mediated superconductivity: Impact of the electron-boson coupling vertex corrections

    NASA Astrophysics Data System (ADS)

    Tazai, Rina; Yamakawa, Youichi; Tsuchiizu, Masahisa; Kontani, Hiroshi

    2016-09-01

    In various multiorbital systems, the emergence of the orbital fluctuations and their role on the pairing mechanism attract increasing attention. To achieve deep understanding on these issues, we perform a functional renormalization group (fRG) study for the two-orbital Hubbard model. The vertex corrections for the electron-boson coupling (U -VC), which are dropped in the Migdal-Eliashberg gap equation, are obtained by solving the RG equation. We reveal that the dressed electron-boson coupling for the charge channel Ûeffc becomes much larger than the bare Coulomb interaction Û 0 due to the U -VC in the presence of moderate spin fluctuations. For this reason, the attractive pairing interaction due to the charge or orbital fluctuations is enlarged by the factor (Ûeffc/Û0) 2≫1 . In contrast, the spin fluctuation pairing interaction is suppressed by the spin-channel U -VC, because of the relation Ûeffs≪Û 0 . The present study demonstrates that the orbital or charge fluctuation pairing mechanism can be realized in various multiorbital systems thanks to the U -VC, such as in Fe-based superconductors.

  3. Pair-Wise and Many-Body Dispersive Interactions Coupled to an Optimally Tuned Range-Separated Hybrid Functional.

    PubMed

    Agrawal, Piyush; Tkatchenko, Alexandre; Kronik, Leeor

    2013-08-13

    We propose a nonempirical, pair-wise or many-body dispersion-corrected, optimally tuned range-separated hybrid functional. This functional retains the advantages of the optimal-tuning approach in the prediction of the electronic structure. At the same time, it gains accuracy in the prediction of binding energies for dispersively bound systems, as demonstrated on the S22 and S66 benchmark sets of weakly bound dimers.

  4. Vertex functions at finite momentum: Application to antiferromagnetic quantum criticality

    NASA Astrophysics Data System (ADS)

    Wölfle, Peter; Abrahams, Elihu

    2016-02-01

    We analyze the three-point vertex function that describes the coupling of fermionic particle-hole pairs in a metal to spin or charge fluctuations at nonzero momentum. We consider Ward identities, which connect two-particle vertex functions to the self-energy, in the framework of a Hubbard model. These are derived using conservation laws following from local symmetries. The generators considered are the spin density and particle density. It is shown that at certain antiferromagnetic critical points, where the quasiparticle effective mass is diverging, the vertex function describing the coupling of particle-hole pairs to the spin density Fourier component at the antiferromagnetic wave vector is also divergent. Then we give an explicit calculation of the irreducible vertex function for the case of three-dimensional antiferromagnetic fluctuations, and show that it is proportional to the diverging quasiparticle effective mass.

  5. Universal spectral signatures in pnictides and cuprates: the role of quasiparticle-pair coupling.

    PubMed

    Sacks, William; Mauger, Alain; Noat, Yves

    2017-11-08

    Understanding the physical properties of a large variety of high-T c superconductors (SC), the cuprate family as well as the more recent iron-based superconductors, is still a major challenge. In particular, these materials exhibit the 'peak-dip-hump' structure in the quasiparticle density of states (DOS). The origin of this structure is explained within our pair-pair interaction (PPI) model: The non-superconducting state consists of incoherent pairs, a 'Cooper-pair glass' which, due to the PPI, undergoes a Bose-like condensation below T c to the coherent SC state. We derive the equations of motion for the quasiparticle operators showing that the DOS 'peak-dip-hump' is caused by the coupling between quasiparticles and excited pair states, or 'super-quasiparticles'. The renormalized SC gap function becomes energy-dependent and non retarded, reproducing accurately the experimental spectra of both pnictides and cuprates, despite the large difference in gap value.

  6. Equilibrium properties and phase diagram of two-dimensional Yukawa systems

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

    Hartmann, P.; Donko, Z.; Kutasi, K.

    Properties of two-dimensional strongly coupled Yukawa systems are explored through molecular dynamics simulations. An effective coupling coefficient {gamma}{sup *} for the liquid phase is introduced on the basis of the constancy of the first peak amplitude of the pair-correlation functions. Thermodynamic quantities are calculated from the pair-correlation function. The solid-liquid transition of the system is investigated through the analysis of the bond-angular order parameter. The static structure function satisfies consistency relation, attesting to the reliability of the computational method. The response is shown to be governed by the correlational part of the inverse compressibility. An analysis of the velocity autocorrelationmore » demonstrates that this latter also exhibits a universal behavior.« less

  7. Bosonic excitations and electron pairing in an electron-doped cuprate superconductor

    NASA Astrophysics Data System (ADS)

    Wang, M. C.; Yu, H. S.; Xiong, J.; Yang, Y.-F.; Luo, S. N.; Jin, K.; Qi, J.

    2018-04-01

    By applying ultrafast optical spectroscopy to electron-doped La1.9Ce0.1CuO4 ±δ , we discern a bosonic mode of electronic origin and provide the evolution of its coupling with the charge carriers as a function of temperature. Our results show that it has the strongest coupling strength near Tc and can fully account for the superconducting pairing. This mode can be associated with the two-dimensional antiferromagnetic spin correlations emerging below a critical temperature T† larger than Tc. Our work may help to establish a quantitative relation between bosonic excitations and superconducting pairing in electron-doped cuprates.

  8. Controlling the superconducting transition by spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Banerjee, N.; Ouassou, J. A.; Zhu, Y.; Stelmashenko, N. A.; Linder, J.; Blamire, M. G.

    2018-05-01

    Whereas considerable evidence exists for the conversion of singlet Cooper pairs into triplet Cooper pairs in the presence of inhomogeneous magnetic fields, recent theoretical proposals have suggested an alternative way to exert control over triplet generation: intrinsic spin-orbit coupling in a homogeneous ferromagnet coupled to a superconductor. Here, we proximity couple Nb to an asymmetric Pt/Co/Pt trilayer, which acts as an effective spin-orbit-coupled ferromagnet owing to structural inversion asymmetry. Unconventional modulation of the superconducting critical temperature as a function of in-plane and out-of-plane applied magnetic fields suggests the presence of triplets that can be controlled by the magnetic orientation of a single homogeneous ferromagnet. Our studies demonstrate an active role of spin-orbit coupling in controlling the triplets, an important step towards the realization of novel superconducting spintronic devices.

  9. Cooper-pair size and binding energy for unconventional superconducting systems

    NASA Astrophysics Data System (ADS)

    Dinóla Neto, F.; Neto, Minos A.; Salmon, Octavio D. Rodriguez

    2018-06-01

    The main proposal of this paper is to analyze the size of the Cooper pairs composed by unbalanced mass fermions from different electronic bands along the BCS-BEC crossover and study the binding energy of the pairs. We are considering an interaction between fermions with different masses leading to an inter-band pairing. In addiction to the attractive interaction we have an hybridization term to couple both bands, which in general acts unfavorable for the pairing between the electrons. We get first order phase transitions as the hybridization breaks the Cooper pairs for the s-wave symmetry of the gap amplitude. The results show the dependence of the Cooper-pair size as a function of the hybridization for T = 0 . We also propose the structure of the binding energy of the inter-band system as a function of the two-bands quasi-particle energies.

  10. Colloid-colloid hydrodynamic interaction around a bend in a quasi-one-dimensional channel.

    PubMed

    Liepold, Christopher; Zarcone, Ryan; Heumann, Tibor; Rice, Stuart A; Lin, Binhua

    2017-07-01

    We report a study of how a bend in a quasi-one-dimensional (q1D) channel containing a colloid suspension at equilibrium that exhibits single-file particle motion affects the hydrodynamic coupling between colloid particles. We observe both structural and dynamical responses as the bend angle becomes more acute. The structural response is an increasing depletion of particles in the vicinity of the bend and an increase in the nearest-neighbor separation in the pair correlation function for particles on opposite sides of the bend. The dynamical response monitored by the change in the self-diffusion [D_{11}(x)] and coupling [D_{12}(x)] terms of the pair diffusion tensor reveals that the pair separation dependence of D_{12} mimics that of the pair correlation function just as in a straight q1D channel. We show that the observed behavior is a consequence of the boundary conditions imposed on the q1D channel: both the single-file motion and the hydrodynamic flow must follow the channel around the bend.

  11. Actinide chemistry using singlet-paired coupled cluster and its combinations with density functionals

    NASA Astrophysics Data System (ADS)

    Garza, Alejandro J.; Sousa Alencar, Ana G.; Scuseria, Gustavo E.

    2015-12-01

    Singlet-paired coupled cluster doubles (CCD0) is a simplification of CCD that relinquishes a fraction of dynamic correlation in order to be able to describe static correlation. Combinations of CCD0 with density functionals that recover specifically the dynamic correlation missing in the former have also been developed recently. Here, we assess the accuracy of CCD0 and CCD0+DFT (and variants of these using Brueckner orbitals) as compared to well-established quantum chemical methods for describing ground-state properties of singlet actinide molecules. The f0 actinyl series (UO22+, NpO23+, PuO24+), the isoelectronic NUN, and thorium (ThO, ThO2+) and nobelium (NoO, NoO2) oxides are studied.

  12. Estimates of electronic coupling for excess electron transfer in DNA

    NASA Astrophysics Data System (ADS)

    Voityuk, Alexander A.

    2005-07-01

    Electronic coupling Vda is one of the key parameters that determine the rate of charge transfer through DNA. While there have been several computational studies of Vda for hole transfer, estimates of electronic couplings for excess electron transfer (ET) in DNA remain unavailable. In the paper, an efficient strategy is established for calculating the ET matrix elements between base pairs in a π stack. Two approaches are considered. First, we employ the diabatic-state (DS) method in which donor and acceptor are represented with radical anions of the canonical base pairs adenine-thymine (AT) and guanine-cytosine (GC). In this approach, similar values of Vda are obtained with the standard 6-31G* and extended 6-31++G** basis sets. Second, the electronic couplings are derived from lowest unoccupied molecular orbitals (LUMOs) of neutral systems by using the generalized Mulliken-Hush or fragment charge methods. Because the radical-anion states of AT and GC are well reproduced by LUMOs of the neutral base pairs calculated without diffuse functions, the estimated values of Vda are in good agreement with the couplings obtained for radical-anion states using the DS method. However, when the calculation of a neutral stack is carried out with diffuse functions, LUMOs of the system exhibit the dipole-bound character and cannot be used for estimating electronic couplings. Our calculations suggest that the ET matrix elements Vda for models containing intrastrand thymine and cytosine bases are essentially larger than the couplings in complexes with interstrand pyrimidine bases. The matrix elements for excess electron transfer are found to be considerably smaller than the corresponding values for hole transfer and to be very responsive to structural changes in a DNA stack.

  13. Colloid-Colloid Hydrodynamic Interaction Around a Bend in a Quasi-One-Dimensional Channel

    NASA Astrophysics Data System (ADS)

    Liepold, Christopher; Zarcone, Ryan; Heumann, Tibor; Lin, Binhua; Rice, Stuart

    We report a study of the correlation between a pair of particles in a colloid suspension in a bent quasi-one-dimensional (q1d) channel as a function of bend angle. As the bend angle becomes more acute, we observe an increasing depletion of particles in the vicinity of the bend and an increase in the nearest-neighbor separation in the pair correlation function for particles on opposite sides of the bend. Further, we observe that the peak value of D12, the coupling term in the pair diffusion tensor that characterizes the effect of the motion of particle 1 on particle 2, coincides with the first peak in the pair correlation function, and that the pair separation dependence of D12 mimics that of the pair correlation function. We show that the observed behavior is a consequence of the geometric constraints imposed by the single-file requirement that the particle centers lie on the centerline of the channel and the requirement that the hydrodynamic flow must follow the channel around the bend. We find that the correlation between a pair of particles in a colloidal suspension in a bent q1D channel has the same functional dependence on the pair correlation function as in a straight q1D channel when measured in a coordinate system that follows the centerline of the bent channel. NSF MRSEC (DMR-1420709), Dreyfus Foundation (SI-14-014).

  14. Strong temperature effect on the sizes of the Cooper pairs in a two-band superconductor

    NASA Astrophysics Data System (ADS)

    Örd, Teet; Rägo, Küllike; Vargunin, Artjom; Litak, Grzegorz

    2018-01-01

    We study the temperature dependencies of the mean sizes of the Cooper pairs in a two-band BCS-type s-wave superconductivity model with coupling cut-off in the momentum space. It is found that, in contrast to single-band systems, the size of Cooper pairs in the weaker superconductivity band can significantly decrease with a temperature increase due to an interband proximity effect. The relevant spatial behaviour of the wave functions of the Cooper pairs is analyzed. The results also indicate a possibility that the size of Cooper pairs in two-band systems may increase with an increase in temperature.

  15. Origins of coevolution between residues distant in protein 3D structures

    PubMed Central

    Ovchinnikov, Sergey; Kamisetty, Hetunandan; Baker, David

    2017-01-01

    Residue pairs that directly coevolve in protein families are generally close in protein 3D structures. Here we study the exceptions to this general trend—directly coevolving residue pairs that are distant in protein structures—to determine the origins of evolutionary pressure on spatially distant residues and to understand the sources of error in contact-based structure prediction. Over a set of 4,000 protein families, we find that 25% of directly coevolving residue pairs are separated by more than 5 Å in protein structures and 3% by more than 15 Å. The majority (91%) of directly coevolving residue pairs in the 5–15 Å range are found to be in contact in at least one homologous structure—these exceptions arise from structural variation in the family in the region containing the residues. Thirty-five percent of the exceptions greater than 15 Å are at homo-oligomeric interfaces, 19% arise from family structural variation, and 27% are in repeat proteins likely reflecting alignment errors. Of the remaining long-range exceptions (<1% of the total number of coupled pairs), many can be attributed to close interactions in an oligomeric state. Overall, the results suggest that directly coevolving residue pairs not in repeat proteins are spatially proximal in at least one biologically relevant protein conformation within the family; we find little evidence for direct coupling between residues at spatially separated allosteric and functional sites or for increased direct coupling between residue pairs on putative allosteric pathways connecting them. PMID:28784799

  16. Coupling effects in the modal emission of colloidal quantum dot microdisk lasers.

    NASA Astrophysics Data System (ADS)

    Lafalce, Evan; Zheng, Qingji; Lin, Chunhao; Smith, Marcus; Malak, Sidney; Jung, Jaehan; Yoon, Young; Lin, Zhiqun; Tsukruk, Vladimir; Vardeny, Z. Valy

    Solution-processed semiconductors such as colloidal quantum dots (CQD) are particularly suited materials for monolithic fabrication of laser microstructures because of their ease of fabrication and compatibility with conventional lithographic techniques. We use the functionality of core/alloyed-shell CQDs to fabricate microdisk lasers of variable size and study the resulting whispering-gallery mode laser emission. In particular we study the effects of near-field coupling on resonant modes of pairs of these lasers with sub-micrometer spacing. We demonstrate the occurrence of lasing modes that originate from the interaction between two such microdisks by means of varying the spatial distribution and magnitude of the gain and loss in the coupled-pair. The transition from emission of modes localized on a single disk to those of the interacting pair is accompanied by coalescence of eigen-frequencies and pump-induced turn-off of lasing, highlighting the role of parity-time symmetry and exceptional point physics. This work was funded by AFOSR through MURI Grant RA 9550-14-1-0037.

  17. Electronic structure and normal vibrations of the 1-ethyl-3-methylimidazolium ethyl sulfate ion pair.

    PubMed

    Dhumal, Nilesh R; Kim, Hyung J; Kiefer, Johannes

    2011-04-21

    Electronic and structural properties of the ion pair 1-ethyl-3-methylimidazolium ethyl sulfate are studied using density functional methods. Three locally stable conformers of the ion pair complex are considered to analyze molecular interactions between its cation and anion. Manifestations of these interactions in the vibrational spectra are discussed and compared with experimental IR and Raman spectroscopy data. NBO analysis and difference electron density coupled with molecular electron density topography are used to interpret the frequency shifts of the normal vibrations of the ion pair, compared to the free anion and cation. Excitation energies of low-lying singlet excited states of the conformers are also studied. The density functional theory results are found to be in a reasonable agreement with experimental UV/vis absorption spectra.

  18. An Ab Initio Study of CuCO

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.

    1994-01-01

    Modified coupled-pair functional (MCPF) calculations and coupled cluster singles and doubles calculations, which include a perturbational estimate of the connected triples [CCSD(T)], yield a bent structure for CuCO, thus, supporting the prediction of a nonlinear structure based on density functional (DF) calculations. Our best estimate for the binding energy is 4.9 +/- 1.4 kcal/mol; this is in better agreement with experiment (6.0 +/- 1.2 kcal/mol) than the DF approach which yields a value (19.6 kcal/mol) significantly larger than experiment.

  19. High-pressure pair distribution function (PDF) measurement using high-energy focused x-ray beam

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

    Hong, Xinguo, E-mail: xhong@bnl.gov; Weidner, Donald J.; Ehm, Lars

    In this paper, we report recent development of the high-pressure pair distribution function (HP-PDF) measurement technique using a focused high-energy X-ray beam coupled with a diamond anvil cell (DAC). The focusing optics consist of a sagittally bent Laue monochromator and Kirkpatrick-Baez (K–B) mirrors. This combination provides a clean high-energy X-ray beam suitable for HP-PDF research. Demonstration of the HP-PDF technique for nanocrystalline platinum under quasi-hydrostatic condition above 30 GPa is presented.

  20. Electron—phonon Coupling and the Superconducting Phase Diagram of the LaAlO3—SrTiO3 Interface

    PubMed Central

    Boschker, Hans; Richter, Christoph; Fillis-Tsirakis, Evangelos; Schneider, Christof W.; Mannhart, Jochen

    2015-01-01

    The superconductor at the LaAlO3—SrTiO3 interface provides a model system for the study of two-dimensional superconductivity in the dilute carrier density limit. Here we experimentally address the pairing mechanism in this superconductor. We extract the electron—phonon spectral function from tunneling spectra and conclude, without ruling out contributions of further pairing channels, that electron—phonon mediated pairing is strong enough to account for the superconducting critical temperatures. Furthermore, we discuss the electron—phonon coupling in relation to the superconducting phase diagram. The electron—phonon spectral function is independent of the carrier density, except for a small part of the phase diagram in the underdoped region. The tunneling measurements reveal that the increase of the chemical potential with increasing carrier density levels off and is zero in the overdoped region of the phase diagram. This indicates that the additionally induced carriers do not populate the band that hosts the superconducting state and that the superconducting order parameter therefore is weakened by the presence of charge carriers in another band. PMID:26169351

  1. Effects of cluster-shell competition and BCS-like pairing in 12C

    NASA Astrophysics Data System (ADS)

    Matsuno, H.; Itagaki, N.

    2017-12-01

    The antisymmetrized quasi-cluster model (AQCM) was proposed to describe α-cluster and jj-coupling shell models on the same footing. In this model, the cluster-shell transition is characterized by two parameters, R representing the distance between α clusters and Λ describing the breaking of α clusters, and the contribution of the spin-orbit interaction, very important in the jj-coupling shell model, can be taken into account starting with the α-cluster model wave function. Not only the closure configurations of the major shells but also the subclosure configurations of the jj-coupling shell model can be described starting with the α-cluster model wave functions; however, the particle-hole excitations of single particles have not been fully established yet. In this study we show that the framework of AQCM can be extended even to the states with the character of single-particle excitations. For ^{12}C, two-particle-two-hole (2p2h) excitations from the subclosure configuration of 0p_{3/2} corresponding to a BCS-like pairing are described, and these shell model states are coupled with the three α-cluster model wave functions. The correlation energy from the optimal configuration can be estimated not only in the cluster part but also in the shell model part. We try to pave the way to establish a generalized description of the nuclear structure.

  2. State-Dependent Cross-Brain Information Flow in Borderline Personality Disorder.

    PubMed

    Bilek, Edda; Stößel, Gabriela; Schäfer, Axel; Clement, Laura; Ruf, Matthias; Robnik, Lydia; Neukel, Corinne; Tost, Heike; Kirsch, Peter; Meyer-Lindenberg, Andreas

    2017-09-01

    Although borderline personality disorder (BPD)-one of the most common, burdensome, and costly psychiatric conditions-is characterized by repeated interpersonal conflict and instable relationships, the neurobiological mechanism of social interactive deficits remains poorly understood. To apply recent advancements in the investigation of 2-person human social interaction to investigate interaction difficulties among people with BPD. Cross-brain information flow in BPD was examined from May 25, 2012, to December 4, 2015, in pairs of participants studied in 2 linked functional magnetic resonance imaging scanners in a university setting. Participants performed a joint attention task. Each pair included a healthy control individual (HC) and either a patient currently fulfilling DSM-IV criteria for BPD (cBPD) (n = 23), a patient in remission for 2 years or more (rBPD) (n = 17), or a second HC (n = 20). Groups were matched for age and educational level. A measure of cross-brain neural coupling was computed following previously published work to indicate synchronized flow between right temporoparietal junction networks (previously shown to host neural coupling abilities in health). This measure is derived from an independent component analysis contrasting the time courses of components between pairs of truly interacting participants compared with bootstrapped control pairs. In the sample including 23 women with cBPD (mean [SD] age, 26.8 [5.7] years), 17 women with rBPD (mean [SD] age, 28.5 [4.3] years), and 80 HCs (mean [SD] age, 24.0 [3.4] years]) investigated as dyads, neural coupling was found to be associated with disorder state (η2 = 0.17; P = .007): while HC-HC pairs showed synchronized neural responses, cBPD-HC pairs exhibited significantly lower neural coupling just above permutation-based data levels (η2 = 0.16; P = .009). No difference was found between neural coupling in rBPD-HC and HC-HC pairs. The neural coupling in patients was significantly associated with childhood adversity (T = 2.3; P = .03). This study provides a neural correlate for a core diagnostic and clinical feature of BPD. Results indicate that hyperscanning may deliver state-associated biomarkers for clinical social neuroscience. In addition, at least some neural deficits of BPD may be more reversible than is currently assumed for personality disorders.

  3. Excitonic couplings between molecular crystal pairs by a multistate approximation

    NASA Astrophysics Data System (ADS)

    Aragó, Juan; Troisi, Alessandro

    2015-04-01

    In this paper, we present a diabatization scheme to compute the excitonic couplings between an arbitrary number of states in molecular pairs. The method is based on an algebraic procedure to find the diabatic states with a desired property as close as possible to that of some reference states. In common with other diabatization schemes, this method captures the physics of the important short-range contributions (exchange, overlap, and charge-transfer mediated terms) but it becomes particularly suitable in presence of more than two states of interest. The method is formulated to be usable with any level of electronic structure calculations and to diabatize different types of states by selecting different molecular properties. These features make the diabatization scheme presented here especially appropriate in the context of organic crystals, where several excitons localized on the same molecular pair may be found close in energy. In this paper, the method is validated on the tetracene crystal dimer, a well characterized case where the charge transfer (CT) states are closer in energy to the Frenkel excitons (FE). The test system was studied as a function of an external electric field (to explore the effect of changing the relative energy of the CT excited state) and as a function of different intermolecular distances (to probe the strength of the coupling between FE and CT states). Additionally, we illustrate how the approximation can be used to include the environment polarization effect.

  4. Exploring biorthonormal transformations of pair-correlation functions in atomic structure variational calculations

    NASA Astrophysics Data System (ADS)

    Verdebout, S.; Jönsson, P.; Gaigalas, G.; Godefroid, M.; Froese Fischer, C.

    2010-04-01

    Multiconfiguration expansions frequently target valence correlation and correlation between valence electrons and the outermost core electrons. Correlation within the core is often neglected. A large orbital basis is needed to saturate both the valence and core-valence correlation effects. This in turn leads to huge numbers of configuration state functions (CSFs), many of which are unimportant. To avoid the problems inherent to the use of a single common orthonormal orbital basis for all correlation effects in the multiconfiguration Hartree-Fock (MCHF) method, we propose to optimize independent MCHF pair-correlation functions (PCFs), bringing their own orthonormal one-electron basis. Each PCF is generated by allowing single- and double-excitations from a multireference (MR) function. This computational scheme has the advantage of using targeted and optimally localized orbital sets for each PCF. These pair-correlation functions are coupled together and with each component of the MR space through a low dimension generalized eigenvalue problem. Nonorthogonal orbital sets being involved, the interaction and overlap matrices are built using biorthonormal transformation of the coupled basis sets followed by a counter-transformation of the PCF expansions. Applied to the ground state of beryllium, the new method gives total energies that are lower than the ones from traditional complete active space (CAS)-MCHF calculations using large orbital active sets. It is fair to say that we now have the possibility to account for, in a balanced way, correlation deep down in the atomic core in variational calculations.

  5. What couples say about their recovery of sexual intimacy after prostatectomy: toward the development of a conceptual model of couples' sexual recovery after surgery for prostate cancer.

    PubMed

    Wittmann, Daniela; Carolan, Marsha; Given, Barbara; Skolarus, Ted A; Crossley, Heather; An, Lawrence; Palapattu, Ganesh; Clark, Patricia; Montie, James E

    2015-02-01

    Interventions designed to help couples recover sexual intimacy after prostatectomy have not been guided by a comprehensive conceptual model. We examined a proposed biopsychosocial conceptual model of couples' sexual recovery that included functional, psychological, and relational aspects of sexuality, surgery-related sexual losses, and grief and mourning as recovery process. We interviewed 20 couples preoperatively and 3 months postoperatively. between 2010 and 2012. Interviews were analyzed with Analytic Induction qualitative methodology, using NVivo software. Paired t-tests described functional assessment data. Study findings led to a revised conceptual model. Couples' experiences were assessed through semi-structured interviews; male participants' sexual function was assessed with the Expanded Prostate Cancer Index Composite and female participants' sexual function with the Female Sexual Function Index. Preoperatively, 30% of men had erectile dysfunction (ED) and 84% of partners were postmenopausal. All valued sexual recovery, but worried about cancer spread and surgery side effects. Faith in themselves and their surgeons led 90% of couples to overestimate erectile recovery. Postoperatively, most men had ED and lost confidence. Couples' sexual activity decreased. Couples reported feeling loss and grief: cancer diagnosis was the first loss, followed by surgery-related sexual losses. Couples' engagement in intentional sex, patients' acceptance of erectile aids, and partners' interest in sex aided the recovery of couples' sexual intimacy recovery. Unselfconscious sex, not returning to erectile function baseline, was seen as the end point. Survey findings documented participants' sexual function losses, confirming qualitative findings. Couples' sexual recovery requires addressing sexual function, feelings about losses, and relationship simultaneously. Perioperative education should emphasize the roles of nerve damage in ED and grief and mourning in sexual recovery. © 2014 International Society for Sexual Medicine.

  6. Spectral broadening of optical transitions in InAs/GaAs coupled quantum dot pairs

    NASA Astrophysics Data System (ADS)

    Kumar, P.; Czarnocki, C.; Jennings, C.; Casara, J.; Monteros, A. L.; Zahbihi, N.; Scheibner, M.; Economou, S. E.; Bracker, A. S.; Pursley, B. C.; Gammon, D.; Carter, S. G.

    The optical transitions in InAs/GaAs coupled quantum dot (CQD) pairs are investigated experimentally. These coupled dot systems provide new means to study the interaction of quantum states with the mechanical modes of the crystal environment. Here, the line width and line shape of CQD optical transitions are analyzed in detail as a function of temperature, excitation power, excitation energy, and tunnel coupling strength. A significant line broadening, up to 25 times the typical lifetime-limited linewidth of single-dot excitons, is being observed at level anti-crossings where the coherent tunnel coupling between spatially direct and indirect exciton states is considerable. The experimental observations are compared with theoretical predictions where linewidth broadening at anti-crossings is attributed to the phonon assisted transitions, and found to be strongly dependent on the energy splitting of the two exciton branches. This work focuses on understanding the linewidth broadening due to the pure dephasing, and fundamental aspects of the interaction of these systems with the local environment. This work was supported by the Defense Threat Reduction Agency, Basic Research Award HDTRA1-15-1-0011.

  7. Optical signatures of coupled quantum dots.

    PubMed

    Stinaff, E A; Scheibner, M; Bracker, A S; Ponomarev, I V; Korenev, V L; Ware, M E; Doty, M F; Reinecke, T L; Gammon, D

    2006-02-03

    An asymmetric pair of coupled InAs quantum dots is tuned into resonance by applying an electric field so that a single hole forms a coherent molecular wave function. The optical spectrum shows a rich pattern of level anticrossings and crossings that can be understood as a superposition of charge and spin configurations of the two dots. Coulomb interactions shift the molecular resonance of the optically excited state (charged exciton) with respect to the ground state (single charge), enabling light-induced coupling of the quantum dots. This result demonstrates the possibility of optically coupling quantum dots for application in quantum information processing.

  8. Optical Signatures of Coupled Quantum Dots

    NASA Astrophysics Data System (ADS)

    Stinaff, E. A.; Scheibner, M.; Bracker, A. S.; Ponomarev, I. V.; Korenev, V. L.; Ware, M. E.; Doty, M. F.; Reinecke, T. L.; Gammon, D.

    2006-02-01

    An asymmetric pair of coupled InAs quantum dots is tuned into resonance by applying an electric field so that a single hole forms a coherent molecular wave function. The optical spectrum shows a rich pattern of level anticrossings and crossings that can be understood as a superposition of charge and spin configurations of the two dots. Coulomb interactions shift the molecular resonance of the optically excited state (charged exciton) with respect to the ground state (single charge), enabling light-induced coupling of the quantum dots. This result demonstrates the possibility of optically coupling quantum dots for application in quantum information processing.

  9. Language style matching predicts relationship initiation and stability.

    PubMed

    Ireland, Molly E; Slatcher, Richard B; Eastwick, Paul W; Scissors, Lauren E; Finkel, Eli J; Pennebaker, James W

    2011-01-01

    Previous relationship research has largely ignored the importance of similarity in how people talk with one another. Using natural language samples, we investigated whether similarity in dyads' use of function words, called language style matching (LSM), predicts outcomes for romantic relationships. In Study 1, greater LSM in transcripts of 40 speed dates predicted increased likelihood of mutual romantic interest (odds ratio = 3.05). Overall, 33.3% of pairs with LSM above the median mutually desired future contact, compared with 9.1% of pairs with LSM at or below the median. In Study 2, LSM in 86 couples' instant messages positively predicted relationship stability at a 3-month follow-up (odds ratio = 1.95). Specifically, 76.7% of couples with LSM greater than the median were still dating at the follow-up, compared with 53.5% of couples with LSM at or below the median. LSM appears to reflect implicit interpersonal processes central to romantic relationships.

  10. Series-Coupled Pairs of Silica Microresonators

    NASA Technical Reports Server (NTRS)

    Savchenkov, Anatoliy; Iltchenko, Vladimir; Maleki, Lute; Handley, Tim

    2009-01-01

    Series-coupled pairs of whispering-gallery-mode optical microresonators have been demonstrated as prototypes of stable, narrow-band-pass photonic filters. Characteristics that are generally considered desirable in a photonic or other narrow-band-pass filter include response as nearly flat as possible across the pass band, sharp roll-off, and high rejection of signals outside the pass band. A single microresonator exhibits a Lorentzian filter function: its peak response cannot be made flatter and its roll-off cannot be made sharper. However, as a matter of basic principle applicable to resonators in general, it is possible to (1) use multiple resonators, operating in series or parallel, to obtain a roll-off sharper, and out-of-band rejection greater, relative to those of a Lorentzian filter function and (2) to make the peak response (the response within the pass band) flatter by tuning the resonators to slightly different resonance frequencies that span the pass band. The first of the two microresonators in each series-coupled pair was a microtorus made of germania-doped silica (containing about 19 mole percent germania), which is a material used for the cores of some optical fibers. The reasons for choosing this material is that exposing it to ultraviolet light causes it to undergo a chemical change that changes its index of refraction and thereby changes the resonance frequency. Hence, this material affords the means to effect the desired slight relative detuning of the two resonators. The second microresonator in each pair was a microsphere of pure silica. The advantage of making one of the resonators a torus instead of a sphere is that its spectrum of whispering-gallery-mode resonances is sparser, as needed to obtain a frequency separation of at least 100 GHz between resonances of the filter as a whole.

  11. Majorana surface modes of nodal topological pairings in spin-3/2 semimetals

    NASA Astrophysics Data System (ADS)

    Yang, Wang; Xiang, Tao; Wu, Congjun

    2017-10-01

    When solid state systems possess active orbital-band structures subject to spin-orbit coupling, their multicomponent electronic structures are often described in terms of effective large-spin fermion models. Their topological structures of superconductivity are beyond the framework of spin singlet and triplet Cooper pairings for spin-1/2 systems. Examples include the half-Heusler compound series of RPtBi, where R stands for a rare-earth element. Their spin-orbit coupled electronic structures are described by the Luttinger-Kohn model with effective spin-3/2 fermions and are characterized by band inversion. Recent experiments provide evidence to unconventional superconductivity in the YPtBi material with nodal spin-septet pairing. We systematically study topological pairing structures in spin-3/2 systems with the cubic group symmetries and calculate the surface Majorana spectra, which exhibit zero energy flat bands, or, cubic dispersion depending on the specific symmetry of the superconducting gap functions. The signatures of these surface states in the quasiparticle interference patterns of tunneling spectroscopy are studied, which can be tested in future experiments.

  12. Distinct neuronal interactions in anterior inferotemporal areas of macaque monkeys during retrieval of object association memory.

    PubMed

    Hirabayashi, Toshiyuki; Tamura, Keita; Takeuchi, Daigo; Takeda, Masaki; Koyano, Kenji W; Miyashita, Yasushi

    2014-07-09

    In macaque monkeys, the anterior inferotemporal cortex, a region crucial for object memory processing, is composed of two adjacent, hierarchically distinct areas, TE and 36, for which different functional roles and neuronal responses in object memory tasks have been characterized. However, it remains unknown how the neuronal interactions differ between these areas during memory retrieval. Here, we conducted simultaneous recordings from multiple single-units in each of these areas while monkeys performed an object association memory task and examined the inter-area differences in neuronal interactions during the delay period. Although memory neurons showing sustained activity for the presented cue stimulus, cue-holding (CH) neurons, interacted with each other in both areas, only those neurons in area 36 interacted with another type of memory neurons coding for the to-be-recalled paired associate (pair-recall neurons) during memory retrieval. Furthermore, pairs of CH neurons in area TE showed functional coupling in response to each individual object during memory retention, whereas the same class of neuron pairs in area 36 exhibited a comparable strength of coupling in response to both associated objects. These results suggest predominant neuronal interactions in area 36 during the mnemonic processing, which may underlie the pivotal role of this brain area in both storage and retrieval of object association memory. Copyright © 2014 the authors 0270-6474/14/349377-12$15.00/0.

  13. Thermophysical properties of krypton-helium gas mixtures from ab initio pair potentials

    PubMed Central

    2017-01-01

    A new potential energy curve for the krypton-helium atom pair was developed using supermolecular ab initio computations for 34 interatomic distances. Values for the interaction energies at the complete basis set limit were obtained from calculations with the coupled-cluster method with single, double, and perturbative triple excitations and correlation consistent basis sets up to sextuple-zeta quality augmented with mid-bond functions. Higher-order coupled-cluster excitations up to the full quadruple level were accounted for in a scheme of successive correction terms. Core-core and core-valence correlation effects were included. Relativistic corrections were considered not only at the scalar relativistic level but also using full four-component Dirac–Coulomb and Dirac–Coulomb–Gaunt calculations. The fitted analytical pair potential function is characterized by a well depth of 31.42 K with an estimated standard uncertainty of 0.08 K. Statistical thermodynamics was applied to compute the krypton-helium cross second virial coefficients. The results show a very good agreement with the best experimental data. Kinetic theory calculations based on classical and quantum-mechanical approaches for the underlying collision dynamics were utilized to compute the transport properties of krypton-helium mixtures in the dilute-gas limit for a large temperature range. The results were analyzed with respect to the orders of approximation of kinetic theory and compared with experimental data. Especially the data for the binary diffusion coefficient confirm the predictive quality of the new potential. Furthermore, inconsistencies between two empirical pair potential functions for the krypton-helium system from the literature could be resolved. PMID:28595411

  14. Thermophysical properties of krypton-helium gas mixtures from ab initio pair potentials

    NASA Astrophysics Data System (ADS)

    Jäger, Benjamin; Bich, Eckard

    2017-06-01

    A new potential energy curve for the krypton-helium atom pair was developed using supermolecular ab initio computations for 34 interatomic distances. Values for the interaction energies at the complete basis set limit were obtained from calculations with the coupled-cluster method with single, double, and perturbative triple excitations and correlation consistent basis sets up to sextuple-zeta quality augmented with mid-bond functions. Higher-order coupled-cluster excitations up to the full quadruple level were accounted for in a scheme of successive correction terms. Core-core and core-valence correlation effects were included. Relativistic corrections were considered not only at the scalar relativistic level but also using full four-component Dirac-Coulomb and Dirac-Coulomb-Gaunt calculations. The fitted analytical pair potential function is characterized by a well depth of 31.42 K with an estimated standard uncertainty of 0.08 K. Statistical thermodynamics was applied to compute the krypton-helium cross second virial coefficients. The results show a very good agreement with the best experimental data. Kinetic theory calculations based on classical and quantum-mechanical approaches for the underlying collision dynamics were utilized to compute the transport properties of krypton-helium mixtures in the dilute-gas limit for a large temperature range. The results were analyzed with respect to the orders of approximation of kinetic theory and compared with experimental data. Especially the data for the binary diffusion coefficient confirm the predictive quality of the new potential. Furthermore, inconsistencies between two empirical pair potential functions for the krypton-helium system from the literature could be resolved.

  15. Asy2/Mer2: an evolutionarily conserved mediator of meiotic recombination, pairing, and global chromosome compaction

    PubMed Central

    Tessé, Sophie; Bourbon, Henri-Marc; Debuchy, Robert; Budin, Karine; Dubois, Emeline; Liangran, Zhang; Antoine, Romain; Piolot, Tristan; Kleckner, Nancy; Zickler, Denise; Espagne, Eric

    2017-01-01

    Meiosis is the cellular program by which a diploid cell gives rise to haploid gametes for sexual reproduction. Meiotic progression depends on tight physical and functional coupling of recombination steps at the DNA level with specific organizational features of meiotic-prophase chromosomes. The present study reveals that every step of this coupling is mediated by a single molecule: Asy2/Mer2. We show that Mer2, identified so far only in budding and fission yeasts, is in fact evolutionarily conserved from fungi (Mer2/Rec15/Asy2/Bad42) to plants (PRD3/PAIR1) and mammals (IHO1). In yeasts, Mer2 mediates assembly of recombination–initiation complexes and double-strand breaks (DSBs). This role is conserved in the fungus Sordaria. However, functional analysis of 13 mer2 mutants and successive localization of Mer2 to axis, synaptonemal complex (SC), and chromatin revealed, in addition, three further important functions. First, after DSB formation, Mer2 is required for pairing by mediating homolog spatial juxtaposition, with implications for crossover (CO) patterning/interference. Second, Mer2 participates in the transfer/maintenance and release of recombination complexes to/from the SC central region. Third, after completion of recombination, potentially dependent on SUMOylation, Mer2 mediates global chromosome compaction and post-recombination chiasma development. Thus, beyond its role as a recombinosome–axis/SC linker molecule, Mer2 has important functions in relation to basic chromosome structure. PMID:29021238

  16. Role of temperature on static correlational properties in a spin-polarized electron gas

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

    Arora, Priya; Moudgil, R. K., E-mail: rkmoudgil@kuk.ac.in; Kumar, Krishan

    We have studied the effect of temperature on the static correlational properties of a spin-polarized three-dimensional electron gas (3DEG) over a wide coupling and temperature regime. This problem has been very recently studied by Brown et al. using the restricted path-integral Monte Carlo (RPIMC) technique in the warm-dense regime. To this endeavor, we have used the finite temperature version of the dynamical mean-field theory of Singwi et al, the so-called quantum STLS (qSTLS) approach. The static density structure factor and the static pair-correlation function are calculated, and compared with the RPIMC simulation data. We find an excellent agreement with themore » simulation at high temperature over a wide coupling range. However, the agreement is seen to somewhat deteriorate with decreasing temperature. The pair-correlation function is found to become small negative for small electron separation. This may be attributed to the inadequacy of the mean-field theory in dealing with the like spin electron correlations in the strong-coupling domain. A nice agreement with RPIMC data at high temperature seems to arise due to weakening of both the exchange and coulomb correlations with rising temperature.« less

  17. Coherence lengths for three-dimensional superconductors in the BCS-Bose picture

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

    Carter, R.M.; Casas, M.; Getino, J.M.

    1995-12-01

    Following an approach similar to that of Miyake or Randeria, Duan, and Shieh in two dimensions, we study a three-dimensional many-fermion gas at zero temperature interacting via some short-ranged two-body potential. To accommodate a possible singularity (e.g., the Coulomb repulsion) in the interaction, the potential is eliminated in favor of the two-body scattering {ital t}-matrix, the low-energy form of which is expressible in terms of the {ital s}-wave scattering length {ital a}{sub {ital s}}. The BCS gap equation for {ital s}-wave pairing is then solved simultaneously with the number equation in order to self-consistently obtain the zero-temperature BCS gap {Delta}more » as well as the chemical potential {mu} as functions of the dimensionless coupling variable {lambda}{equivalent_to}{ital k}{sub {ital F}}{ital a}{sub {ital s}}, where {ital k}{sub {ital F}} is the Fermi momentum. Results are valid for arbitrary coupling strength, and in the weak coupling limit reproduce the standard BCS results. Finally, root-mean-square pair sizes are obtained as a function of {lambda} and compared with experimental values.« less

  18. Optical Properties of Vibronically Coupled Cy3 Dimers on DNA Scaffolds.

    PubMed

    Cunningham, Paul D; Kim, Young C; Díaz, Sebastián A; Buckhout-White, Susan; Mathur, Divita; Medintz, Igor L; Melinger, Joseph S

    2018-05-17

    We examine the effect of electronic coupling on the optical properties of Cy3 dimers attached to DNA duplexes as a function of base pair (bp) separation using steady-state and time-resolved spectroscopy. For close Cy3-Cy3 separations, 0 and 1 bp between dyes, intermediate to strong electronic coupling is revealed by modulation of the absorption and fluorescence properties including spectral band shape, peak wavelength, and excited-state lifetime. Using a vibronic exciton model, we estimate coupling strengths of 150 and 266 cm -1 for the 1 and 0 bp separations, respectively, which are comparable to those found in natural light-harvesting complexes. For the strongest electronic coupling (0 bp separation), we observe that the absorption band shape is strongly affected by the base pairs that surround the dyes, where more strongly hydrogen-bonded G-C pairs produce a red-shifted absorption spectrum consistent with a J-type dimer. This effect is studied theoretically using molecular dynamics simulation, which predicts an in-line dye configuration that is consistent with the experimental J-type spectrum. When the Cy3 dimers are in a standard aqueous buffer, the presence of relatively strong electronic coupling is accompanied by decreased fluorescence lifetime, suggesting that it promotes nonradiative relaxation in cyanine dyes. However, we show that the use of a viscous solvent can suppress this nonradiative recombination and thereby restore the dimer fluorescent emission. Ultrafast transient absorption measurements of Cy3 dimers in both standard aqueous buffer and viscous glycerol buffer suggest that sufficiently strong electronic coupling increases the probability of excited-state relaxation through a dark state that is related to Cy3 torsional motion.

  19. Efficient and accurate local single reference correlation methods for high-spin open-shell molecules using pair natural orbitals

    NASA Astrophysics Data System (ADS)

    Hansen, Andreas; Liakos, Dimitrios G.; Neese, Frank

    2011-12-01

    A production level implementation of the high-spin open-shell (spin unrestricted) single reference coupled pair, quadratic configuration interaction and coupled cluster methods with up to doubly excited determinants in the framework of the local pair natural orbital (LPNO) concept is reported. This work is an extension of the closed-shell LPNO methods developed earlier [F. Neese, F. Wennmohs, and A. Hansen, J. Chem. Phys. 130, 114108 (2009), 10.1063/1.3086717; F. Neese, A. Hansen, and D. G. Liakos, J. Chem. Phys. 131, 064103 (2009), 10.1063/1.3173827]. The internal space is spanned by localized orbitals, while the external space for each electron pair is represented by a truncated PNO expansion. The laborious integral transformation associated with the large number of PNOs becomes feasible through the extensive use of density fitting (resolution of the identity (RI)) techniques. Technical complications arising for the open-shell case and the use of quasi-restricted orbitals for the construction of the reference determinant are discussed in detail. As in the closed-shell case, only three cutoff parameters control the average number of PNOs per electron pair, the size of the significant pair list, and the number of contributing auxiliary basis functions per PNO. The chosen threshold default values ensure robustness and the results of the parent canonical methods are reproduced to high accuracy. Comprehensive numerical tests on absolute and relative energies as well as timings consistently show that the outstanding performance of the LPNO methods carries over to the open-shell case with minor modifications. Finally, hyperfine couplings calculated with the variational LPNO-CEPA/1 method, for which a well-defined expectation value type density exists, indicate the great potential of the LPNO approach for the efficient calculation of molecular properties.

  20. Optomechanical oscillator pumped and probed by optically two isolated photonic crystal cavity systems.

    PubMed

    Tian, Feng; Sumikura, Hisashi; Kuramochi, Eiichi; Taniyama, Hideaki; Takiguchi, Masato; Notomi, Masaya

    2016-11-28

    Optomechanical control of on-chip emitters is an important topic related to integrated all-optical circuits. However, there is neither a realization nor a suitable optomechanical structure for this control. The biggest obstacle is that the emission signal can hardly be distinguished from the pump light because of the several orders' power difference. In this study, we designed and experimentally verified an optomechanical oscillation system, in which a lumped mechanical oscillator connected two optically isolated pairs of coupled one-dimensional photonic crystal cavities. As a functional device, the two pairs of coupled cavities were respectively used as an optomechanical pump for the lumped oscillator (cavity pair II, wavelengths were designed to be within a 1.5 μm band) and a modulation target of the lumped oscillator (cavity pair I, wavelengths were designed to be within a 1.2 μm band). By conducting finite element method simulations, we found that the lumped-oscillator-supported configurations of both cavity pairs enhance the optomechanical interactions, especially for higher order optical modes, compared with their respective conventional side-clamped configurations. Besides the desired first-order in-plane antiphase mechanical mode, other mechanical modes of the lumped oscillator were investigated and found to possibly have optomechanical applications with a versatile degree of freedom. In experiments, the oscillator's RF spectra were probed using both cavity pairs I and II, and the results matched those of the simulations. Dynamic detuning of the optical spectrum of cavity pair I was then implemented with a pumped lumped oscillator. This was the first demonstration of an optomechanical lumped oscillator connecting two optically isolated pairs of coupled cavities, whose biggest advantage is that one cavity pair can be modulated with an lumped oscillator without interference from the pump light in the other cavity pair. Thus, the oscillator is a suitable platform for optomechanical control of integrated lasers, cavity quantum electrodynamics, and spontaneous emission. Furthermore, this device may open the door on the study of interactions between photons, phonons, and excitons in the quantum regime.

  1. Mixed coherent states in coupled chaotic systems: Design of secure wireless communication

    NASA Astrophysics Data System (ADS)

    Vigneshwaran, M.; Dana, S. K.; Padmanaban, E.

    2016-12-01

    A general coupling design is proposed to realize a mixed coherent (MC) state: coexistence of complete synchronization, antisynchronization, and amplitude death in different pairs of similar state variables of the coupled chaotic system. The stability of coupled system is ensured by the Lyapunov function and a scaling of each variable is also separately taken care of. When heterogeneity as a parameter mismatch is introduced in the coupled system, the coupling function facilitates to retain its coherence and displays the global stability with renewed scaling factor. Robust synchronization features facilitated by a MC state enable to design a dual modulation scheme: binary phase shift key (BPSK) and parameter mismatch shift key (PMSK), for secure data transmission. Two classes of decoders (coherent and noncoherent) are discussed, the noncoherent decoder shows better performance over the coherent decoder, mostly a noncoherent demodulator is preferred in biological implant applications. Both the modulation schemes are demonstrated numerically by using the Lorenz oscillator and the BPSK scheme is demonstrated experimentally using radio signals.

  2. Spectral properties of excitons in the bilayer graphene

    NASA Astrophysics Data System (ADS)

    Apinyan, V.; Kopeć, T. K.

    2018-01-01

    In this paper, we consider the spectral properties of the bilayer graphene with the local excitonic pairing interaction between the electrons and holes. We consider the generalized Hubbard model, which includes both intralayer and interlayer Coulomb interaction parameters. The solution of the excitonic gap parameter is used to calculate the electronic band structure, single-particle spectral functions, the hybridization gap, and the excitonic coherence length in the bilayer graphene. We show that the local interlayer Coulomb interaction is responsible for the semimetal-semiconductor transition in the double layer system, and we calculate the hybridization gap in the band structure above the critical interaction value. The formation of the excitonic band gap is reported as the threshold process and the momentum distribution functions have been calculated numerically. We show that in the weak coupling limit the system is governed by the Bardeen-Cooper-Schrieffer (BCS)-like pairing state. Contrary, in the strong coupling limit the excitonic condensate states appear in the semiconducting phase, by forming the Dirac's pockets in the reciprocal space.

  3. The G protein-coupled receptors deorphanization landscape.

    PubMed

    Laschet, Céline; Dupuis, Nadine; Hanson, Julien

    2018-07-01

    G protein-coupled receptors (GPCRs) are usually highlighted as being both the largest family of membrane proteins and the most productive source of drug targets. However, most of the GPCRs are understudied and hence cannot be used immediately for innovative therapeutic strategies. Besides, there are still around 100 orphan receptors, with no described endogenous ligand and no clearly defined function. The race to discover new ligands for these elusive receptors seems to be less intense than before. Here, we present an update of the various strategies employed to assign a function to these receptors and to discover new ligands. We focus on the recent advances in the identification of endogenous ligands with a detailed description of newly deorphanized receptors. Replication being a key parameter in these endeavors, we also discuss the latest controversies about problematic ligand-receptor pairings. In this context, we propose several recommendations in order to strengthen the reporting of new ligand-receptor pairs. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. A Semiclassical Derivation of the QCD Coupling

    NASA Technical Reports Server (NTRS)

    Batchelor, David

    2009-01-01

    The measured value of the QCD coupling alpha(sub s) at the energy M(sub Zo), the variation of alpha(sub s) as a function of energy in QCD, and classical relativistic dynamics are used to investigate virtual pairs of quarks and antiquarks in vacuum fluctuations. For virtual pairs of bottom quarks and antiquarks, the pair lifetime in the classical model agrees with the lifetime from quantum mechanics to good approximation, and the action integral in the classical model agrees as well with the action that follows from the Uncertainty Principle. This suggests that the particles might have small de Broglie wavelengths and behave with well-localized pointlike dynamics. It also permits alpha(sub s) at the mass energy twice the bottom quark mass to be expressed as a simple fraction: 3/16. This is accurate to approximately 10%. The model in this paper predicts the measured value of alpha(sub s)(M(sub Zo)) to be 0.121, which is in agreement with recent measurements within statistical uncertainties.

  5. Singlet-paired coupled cluster theory for open shells

    NASA Astrophysics Data System (ADS)

    Gomez, John A.; Henderson, Thomas M.; Scuseria, Gustavo E.

    2016-06-01

    Restricted single-reference coupled cluster theory truncated to single and double excitations accurately describes weakly correlated systems, but often breaks down in the presence of static or strong correlation. Good coupled cluster energies in the presence of degeneracies can be obtained by using a symmetry-broken reference, such as unrestricted Hartree-Fock, but at the cost of good quantum numbers. A large body of work has shown that modifying the coupled cluster ansatz allows for the treatment of strong correlation within a single-reference, symmetry-adapted framework. The recently introduced singlet-paired coupled cluster doubles (CCD0) method is one such model, which recovers correct behavior for strong correlation without requiring symmetry breaking in the reference. Here, we extend singlet-paired coupled cluster for application to open shells via restricted open-shell singlet-paired coupled cluster singles and doubles (ROCCSD0). The ROCCSD0 approach retains the benefits of standard coupled cluster theory and recovers correct behavior for strongly correlated, open-shell systems using a spin-preserving ROHF reference.

  6. Mirror Neurons Modeled Through Spike-Timing-Dependent Plasticity are Affected by Channelopathies Associated with Autism Spectrum Disorder.

    PubMed

    Antunes, Gabriela; Faria da Silva, Samuel F; Simoes de Souza, Fabio M

    2018-06-01

    Mirror neurons fire action potentials both when the agent performs a certain behavior and watches someone performing a similar action. Here, we present an original mirror neuron model based on the spike-timing-dependent plasticity (STDP) between two morpho-electrical models of neocortical pyramidal neurons. Both neurons fired spontaneously with basal firing rate that follows a Poisson distribution, and the STDP between them was modeled by the triplet algorithm. Our simulation results demonstrated that STDP is sufficient for the rise of mirror neuron function between the pairs of neocortical neurons. This is a proof of concept that pairs of neocortical neurons associating sensory inputs to motor outputs could operate like mirror neurons. In addition, we used the mirror neuron model to investigate whether channelopathies associated with autism spectrum disorder could impair the modeled mirror function. Our simulation results showed that impaired hyperpolarization-activated cationic currents (Ih) affected the mirror function between the pairs of neocortical neurons coupled by STDP.

  7. Relativistic coupled cluster theory based on the no-pair Dirac-Coulomb-Breit Hamiltonian: Relativistic pair correlation energies of the Xe atom

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

    Eliav, E.; Kaldor, U.; Ishikawa, Y.

    1994-12-31

    Relativistic pair correlation energies of Xe were computed by employing a recently developed relativistic coupled cluster theory based on the no-pair Dirac-Coulomb-Breit Hamiltonian. The matrix Dirac-Fock-Breit SCF and relativistic coupled cluster calculations were performed by means of expansion in basis sets of well-tempered Gaussian spinors. A detailed study of the pair correlation energies in Xe is performed, in order to investigate the effects of the low-frequency Breit interaction on the correlation energies of Xe. Nonadditivity of correlation and relativistic (particularly Breit) effects is discussed.

  8. Molecular switching behavior in isosteric DNA base pairs.

    PubMed

    Jissy, A K; Konar, Sukanya; Datta, Ayan

    2013-04-15

    The structures and proton-coupled behavior of adenine-thymine (A-T) and a modified base pair containing a thymine isostere, adenine-difluorotoluene (A-F), are studied in different solvents by dispersion-corrected density functional theory. The stability of the canonical Watson-Crick base pair and the mismatched pair in various solvents with low and high dielectric constants is analyzed. It is demonstrated that A-F base pairing is favored in solvents with low dielectric constant. The stabilization and conformational changes induced by protonation are also analyzed for the natural as well as the mismatched base pair. DNA sequences capable of changing their sequence conformation on protonation are used in the construction of pH-based molecular switches. An acidic medium has a profound influence in stabilizing the isostere base pair. Such a large gain in stability on protonation leads to an interesting pH-controlled molecular switch, which can be incorporated in a natural DNA tract. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Characteristics of manipulator for industrial robot with three rotational pairs having parallel axes

    NASA Astrophysics Data System (ADS)

    Poteyev, M. I.

    1986-01-01

    The dynamics of a manipulator with three rotatinal kinematic pairs having parallel axes are analyzed, for application in an industrial robot. The system of Lagrange equations of the second kind, describing the motion of such a mechanism in terms of kinetic energy in generalized coordinates, is reduced to equations of motion in terms of Newton's laws. These are useful not only for either determining the moments of force couples which will produce a prescribed motion or, conversely determining the motion which given force couples will produce but also for solving optimization problems under constraints in both cases and for estimating dynamic errors. As a specific example, a manipulator with all three axes of vertical rotation is considered. The performance of this manipulator, namely the parameters of its motion as functions of time, is compared with that of a manipulator having one rotational and two translational kinematic pairs. Computer aided simulation of their motion on the basis of ideal models, with all three links represented by identical homogeneous bars, has yielded velocity time diagrams which indicate that the manipulator with three rotational pairs is 4.5 times faster.

  10. Superconducting pairing of topological surface states in bismuth selenide films on niobium

    PubMed Central

    Zhang, Can; Tsuzuki, Akihiro

    2018-01-01

    A topological insulator film coupled to a simple isotropic s-wave superconductor substrate can foster helical pairing of the Dirac fermions associated with the topological surface states. Experimental realization of such a system is exceedingly difficult, however using a novel “flip-chip” technique, we have prepared single-crystalline Bi2Se3 films with predetermined thicknesses in terms of quintuple layers (QLs) on top of Nb substrates fresh from in situ cleavage. Our angle-resolved photoemission spectroscopy (ARPES) measurements of the film surface disclose superconducting gaps and coherence peaks of similar magnitude for both the topological surface states and bulk states. The ARPES spectral map as a function of temperature and film thickness up to 10 QLs reveals key characteristics relevant to the mechanism of coupling between the topological surface states and the superconducting Nb substrate; the effective coupling length is found to be much larger than the decay length of the topological surface states. PMID:29719866

  11. Exciton coupling between enones: Quassinoids revisited.

    PubMed

    Pescitelli, Gennaro; Di Bari, Lorenzo

    2017-09-01

    The electronic circular dichroism (ECD) spectra of two previously reported quassinoids containing a pair of enone chromophores are revisited to gain insight into the consistency and applicability of the exciton chirality method. Our study is based on time-dependent Density Functional Theory calculations, transition and orbital analysis, and numerical exciton coupling calculations. In quassin (1) the enone/enone exciton coupling is quasi-degenerate, yielding strong rotational strengths that account for the observed ECD spectrum in the enone π-π* region. In perforalactone C (2) the nondegenerate coupling produces weak rotational strengths, and the ECD spectrum is dominated by other mechanisms of optical activity. We remark the necessity of a careful application of the nondegenerate exciton coupling method in similar cases. © 2017 Wiley Periodicals, Inc.

  12. Asy2/Mer2: an evolutionarily conserved mediator of meiotic recombination, pairing, and global chromosome compaction.

    PubMed

    Tessé, Sophie; Bourbon, Henri-Marc; Debuchy, Robert; Budin, Karine; Dubois, Emeline; Liangran, Zhang; Antoine, Romain; Piolot, Tristan; Kleckner, Nancy; Zickler, Denise; Espagne, Eric

    2017-09-15

    Meiosis is the cellular program by which a diploid cell gives rise to haploid gametes for sexual reproduction. Meiotic progression depends on tight physical and functional coupling of recombination steps at the DNA level with specific organizational features of meiotic-prophase chromosomes. The present study reveals that every step of this coupling is mediated by a single molecule: Asy2/Mer2. We show that Mer2, identified so far only in budding and fission yeasts, is in fact evolutionarily conserved from fungi (Mer2/Rec15/Asy2/Bad42) to plants (PRD3/PAIR1) and mammals (IHO1). In yeasts, Mer2 mediates assembly of recombination-initiation complexes and double-strand breaks (DSBs). This role is conserved in the fungus Sordaria However, functional analysis of 13 mer2 mutants and successive localization of Mer2 to axis, synaptonemal complex (SC), and chromatin revealed, in addition, three further important functions. First, after DSB formation, Mer2 is required for pairing by mediating homolog spatial juxtaposition, with implications for crossover (CO) patterning/interference. Second, Mer2 participates in the transfer/maintenance and release of recombination complexes to/from the SC central region. Third, after completion of recombination, potentially dependent on SUMOylation, Mer2 mediates global chromosome compaction and post-recombination chiasma development. Thus, beyond its role as a recombinosome-axis/SC linker molecule, Mer2 has important functions in relation to basic chromosome structure. © 2017 Tessé et al.; Published by Cold Spring Harbor Laboratory Press.

  13. Defragged Binary I Ching Genetic Code Chromosomes Compared to Nirenberg’s and Transformed into Rotating 2D Circles and Squares and into a 3D 100% Symmetrical Tetrahedron Coupled to a Functional One to Discern Start From Non-Start Methionines through a Stella Octangula

    PubMed Central

    Castro-Chavez, Fernando

    2012-01-01

    Background Three binary representations of the genetic code according to the ancient I Ching of Fu-Xi will be presented, depending on their defragging capabilities by pairing based on three biochemical properties of the nucleic acids: H-bonds, Purine/Pyrimidine rings, and the Keto-enol/Amino-imino tautomerism, yielding the last pair a 32/32 single-strand self-annealed genetic code and I Ching tables. Methods Our working tool is the ancient binary I Ching's resulting genetic code chromosomes defragged by vertical and by horizontal pairing, reverse engineered into non-binaries of 2D rotating 4×4×4 circles and 8×8 squares and into one 3D 100% symmetrical 16×4 tetrahedron coupled to a functional tetrahedron with apical signaling and central hydrophobicity (codon formula: 4[1(1)+1(3)+1(4)+4(2)]; 5:5, 6:6 in man) forming a stella octangula, and compared to Nirenberg's 16×4 codon table (1965) pairing the first two nucleotides of the 64 codons in axis y. Results One horizontal and one vertical defragging had the start Met at the center. Two, both horizontal and vertical pairings produced two pairs of 2×8×4 genetic code chromosomes naturally arranged (M and I), rearranged by semi-introversion of central purines or pyrimidines (M' and I') and by clustering hydrophobic amino acids; their quasi-identity was disrupted by amino acids with odd codons (Met and Tyr pairing to Ile and TGA Stop); in all instances, the 64-grid 90° rotational ability was restored. Conclusions We defragged three I Ching representations of the genetic code while emphasizing Nirenberg's historical finding. The synthetic genetic code chromosomes obtained reflect the protective strategy of enzymes with a similar function, having both humans and mammals a biased G-C dominance of three H-bonds in the third nucleotide of their most used codons per amino acid, as seen in one chromosome of the i, M and M' genetic codes, while a two H-bond A-T dominance was found in their complementary chromosome, as seen in invertebrates and plants. The reverse engineering of chromosome I' into 2D rotating circles and squares was undertaken, yielding a 100% symmetrical 3D geometry which was coupled to a previously obtained genetic code tetrahedron in order to differentiate the start methionine from the methionine that is acting as a codifying non-start codon. PMID:23431415

  14. Interlayer-coupled spin vortex pairs and their response to external magnetic fields

    NASA Astrophysics Data System (ADS)

    Wintz, Sebastian; Bunce, Christopher; Banholzer, Anja; Körner, Michael; Strache, Thomas; Mattheis, Roland; McCord, Jeffrey; Raabe, Jörg; Quitmann, Christoph; Erbe, Artur; Fassbender, Jürgen

    2012-06-01

    We report on the response of multilayer spin textures to static magnetic fields. Coupled magnetic vortex pairs in trilayer elements (ferromagnetic/nonmagnetic/ferromagnetic) are imaged directly by means of layer-selective magnetic x-ray microscopy. We observe two different circulation configurations with parallel and opposing senses of magnetization rotation at remanence. Upon application of a field, all of the vortex pairs investigated react with a displacement of their cores. For purely dipolar coupled pairs, the individual core displacements are similar to those of an isolated single-layer vortex, but also a noticeable effect of the mutual stray fields is detected. Vortex pairs that are linked by an additional interlayer exchange coupling (IEC), which is either ferromagnetic or antiferromagnetic, mainly exhibit a layer-congruent response. We find that, apart from a possible decoupling at higher fields, these strict IEC vortex pairs can be described by a single-layer model with effective material parameters. This result implies the possibility to design multilayer spin structures with arbitrary effective magnetization.

  15. Magnon-induced superconductivity in a topological insulator coupled to ferromagnetic and antiferromagnetic insulators

    NASA Astrophysics Data System (ADS)

    Hugdal, Henning G.; Rex, Stefan; Nogueira, Flavio S.; Sudbø, Asle

    2018-05-01

    We study the effective interactions between Dirac fermions on the surface of a three-dimensional topological insulator due to the proximity coupling to the magnetic fluctuations in a ferromagnetic or antiferromagnetic insulator. Our results show that the magnetic fluctuations can mediate attractive interactions between Dirac fermions of both Amperean and BCS types. In the ferromagnetic case, we find pairing between fermions with parallel momenta, so-called Amperean pairing, whenever the effective Lagrangian for the magnetic fluctuations does not contain a quadratic term. The pairing interaction also increases with increasing Fermi momentum and is in agreement with previous studies in the limit of high chemical potential. If a quadratic term is present, the pairing is instead of BCS type above a certain chemical potential. In the antiferromagnetic case, BCS pairing occurs when the ferromagnetic coupling between magnons on the same sublattice exceeds the antiferromagnetic coupling between magnons on different sublattices. Outside this region in parameter space, we again find that Amperean pairing is realized.

  16. Barrier distributions and signatures of transfer channels in the Ca40+Ni58,64 fusion reactions at energies around and below the Coulomb barrier

    NASA Astrophysics Data System (ADS)

    Bourgin, D.; Courtin, S.; Haas, F.; Stefanini, A. M.; Montagnoli, G.; Goasduff, A.; Montanari, D.; Corradi, L.; Fioretto, E.; Huiming, J.; Scarlassara, F.; Rowley, N.; Szilner, S.; Mijatović, T.

    2014-10-01

    Background: The nuclear structure of colliding nuclei is known to influence the fusion process. Couplings of the relative motion to nuclear shape deformations and vibrations lead to an enhancement of the sub-barrier fusion cross section in comparison with the predictions of one-dimensional barrier penetration models. This enhancement is explained by coupled-channels calculations including these couplings. The sub-barrier fusion cross section is also affected by nucleon transfer channels between the colliding nuclei. Purpose: The aim of the present experiment is to investigate the influence of the projectile and target nuclear structures on the fusion cross sections in the Ca40+Ni58 and Ca40+Ni64 systems. Methods: The experimental and theoretical fusion excitation functions as well as the barrier distributions were compared for these two systems. Coupled-channels calculations were performed using the ccfull code. Results: Good agreement was found between the measured and calculated fusion cross sections for the Ca40+Ni58 system. The situation is different for the Ca40+Ni64 system where the coupled-channels calculations with no nucleon transfer clearly underestimate the fusion cross sections below the Coulomb barrier. The fusion excitation function was, however, well reproduced at low and high energies by including the coupling to the neutron pair-transfer channel in the calculations. Conclusions: The nuclear structure of the colliding nuclei influences the fusion cross sections below the Coulomb barrier for both Ca40+Ni58,64 systems. Moreover, we highlighted the effect of the neutron pair-transfer channel on the fusion cross sections in Ca40+Ni64.

  17. Higgs pair production in vector-boson fusion at the LHC and beyond.

    PubMed

    Bishara, Fady; Contino, Roberto; Rojo, Juan

    2017-01-01

    The production of pairs of Higgs bosons at hadron colliders provides unique information on the Higgs sector and on the mechanism underlying electroweak symmetry breaking (EWSB). Most studies have concentrated on the gluon-fusion production mode which has the largest cross section. However, despite its small production rate, the vector-boson fusion channel can also be relevant since even small modifications of the Higgs couplings to vector bosons induce a striking increase of the cross section as a function of the invariant mass of the Higgs boson pair. In this work we exploit this unique signature to propose a strategy to extract the hhVV quartic coupling and provide model-independent constraints on theories where EWSB is driven by new strong interactions. We take advantage of the higher signal yield of the [Formula: see text] final state and make extensive use of jet-substructure techniques to reconstruct signal events with a boosted topology, characteristic of large partonic energies, where each Higgs boson decays to a single collimated jet. Our results demonstrate that the hhVV coupling can be measured with 45% (20%) precision at the LHC for [Formula: see text] (3000) fb[Formula: see text], while a 1% precision can be achieved at a 100 TeV collider.

  18. Lithium formate for EPR dosimetry: radiation-induced radical trapping at low temperatures.

    PubMed

    Krivokapić, André; Aalbergsjø, Siv G; De Cooman, Hendrik; Hole, Eli Olaug; Nelson, William H; Sagstuen, Einar

    2014-05-01

    Radiation-induced primary radicals in lithium formate. A material used in EPR dosimetry have been studied using electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR) and ENDOR-Induced EPR (EIE) techniques. In this study, single crystals were X irradiated at 6-8 K and radical formation at these and higher temperatures were investigated. Periodic density functional theory calculations were used to assist in assigning the radical structures. Mainly two radicals are present at 6 K, the well-known CO2(•-) radical and a protonated electron-gain product. Hyperfine coupling tensors for proton and lithium interactions were obtained for these two radicals and show that the latter radical exists in four conformations with various degrees of bending at the radical center. Pairs of CO2(•-) radicals were also observed and the tensor for the electron-electron dipolar coupling was determined for the strongest coupled pair, which exhibited the largest spectral intensity. Upon warming, both the radical pairs and the reduction product decay, the latter apparently by a transient species. Above 200 K the EPR spectrum was mainly due to the CO2(•-) (mono) radicals, which were previously characterized as the dominant species present at room temperature and which account for the dosimetric EPR signal.

  19. Pair mobility functions for rigid spheres in concentrated colloidal dispersions: Force, torque, translation, and rotation

    NASA Astrophysics Data System (ADS)

    Zia, Roseanna N.; Swan, James W.; Su, Yu

    2015-12-01

    The formulation of detailed models for the dynamics of condensed soft matter including colloidal suspensions and other complex fluids requires accurate description of the physical forces between microstructural constituents. In dilute suspensions, pair-level interactions are sufficient to capture hydrodynamic, interparticle, and thermodynamic forces. In dense suspensions, many-body interactions must be considered. Prior analytical approaches to capturing such interactions such as mean-field approaches replace detailed interactions with averaged approximations. However, long-range coupling and effects of concentration on local structure, which may play an important role in, e.g., phase transitions, are smeared out in such approaches. An alternative to such approximations is the detailed modeling of hydrodynamic interactions utilizing precise couplings between moments of the hydrodynamic traction on a suspended particle and the motion of that or other suspended particles. For two isolated spheres, a set of these functions was calculated by Jeffrey and Onishi [J. Fluid Mech. 139, 261-290 (1984)] and Jeffrey [J. Phys. Fluids 4, 16-29 (1992)]. Along with pioneering work by Batchelor, these are the touchstone for low-Reynolds-number hydrodynamic interactions and have been applied directly in the solution of many important problems related to the dynamics of dilute colloidal dispersions [G. K. Batchelor and J. T. Green, J. Fluid Mech. 56, 375-400 (1972) and G. K. Batchelor, J. Fluid Mech. 74, 1-29 (1976)]. Toward extension of these functions to concentrated systems, here we present a new stochastic sampling technique to rapidly calculate an analogous set of mobility functions describing the hydrodynamic interactions between two hard spheres immersed in a suspension of arbitrary concentration, utilizing accelerated Stokesian dynamics simulations. These mobility functions provide precise, radially dependent couplings of hydrodynamic force and torque to particle translation and rotation, for arbitrary colloid volume fraction ϕ. The pair mobilities (describing entrainment of one particle by the disturbance flow created by another) decay slowly with separation distance: as 1/r, for volume fractions 0.05 ≤ ϕ ≤ 0.5. For the relative mobility, we find an initially rapid growth as a pair separates, followed by a slow, 1/r growth. Up to ϕ ≤ 0.4, the relative mobility does not reached the far-field value even beyond separations of many particle sizes. In the case of ϕ = 0.5, the far-field asymptote is reached but only at a separation of eight radii and after a slow 1/r growth. At these higher concentrations, the coefficients also reveal liquid-like structural effects on pair mobility at close separations. These results confirm that long-range many-body hydrodynamic interactions are an essential part of the dynamics of concentrated systems and that care must be taken when applying renormalization schemes.

  20. Pair mobility functions for rigid spheres in concentrated colloidal dispersions: Force, torque, translation, and rotation.

    PubMed

    Zia, Roseanna N; Swan, James W; Su, Yu

    2015-12-14

    The formulation of detailed models for the dynamics of condensed soft matter including colloidal suspensions and other complex fluids requires accurate description of the physical forces between microstructural constituents. In dilute suspensions, pair-level interactions are sufficient to capture hydrodynamic, interparticle, and thermodynamic forces. In dense suspensions, many-body interactions must be considered. Prior analytical approaches to capturing such interactions such as mean-field approaches replace detailed interactions with averaged approximations. However, long-range coupling and effects of concentration on local structure, which may play an important role in, e.g., phase transitions, are smeared out in such approaches. An alternative to such approximations is the detailed modeling of hydrodynamic interactions utilizing precise couplings between moments of the hydrodynamic traction on a suspended particle and the motion of that or other suspended particles. For two isolated spheres, a set of these functions was calculated by Jeffrey and Onishi [J. Fluid Mech. 139, 261-290 (1984)] and Jeffrey [J. Phys. Fluids 4, 16-29 (1992)]. Along with pioneering work by Batchelor, these are the touchstone for low-Reynolds-number hydrodynamic interactions and have been applied directly in the solution of many important problems related to the dynamics of dilute colloidal dispersions [G. K. Batchelor and J. T. Green, J. Fluid Mech. 56, 375-400 (1972) and G. K. Batchelor, J. Fluid Mech. 74, 1-29 (1976)]. Toward extension of these functions to concentrated systems, here we present a new stochastic sampling technique to rapidly calculate an analogous set of mobility functions describing the hydrodynamic interactions between two hard spheres immersed in a suspension of arbitrary concentration, utilizing accelerated Stokesian dynamics simulations. These mobility functions provide precise, radially dependent couplings of hydrodynamic force and torque to particle translation and rotation, for arbitrary colloid volume fraction ϕ. The pair mobilities (describing entrainment of one particle by the disturbance flow created by another) decay slowly with separation distance: as 1/r, for volume fractions 0.05 ≤ ϕ ≤ 0.5. For the relative mobility, we find an initially rapid growth as a pair separates, followed by a slow, 1/r growth. Up to ϕ ≤ 0.4, the relative mobility does not reached the far-field value even beyond separations of many particle sizes. In the case of ϕ = 0.5, the far-field asymptote is reached but only at a separation of eight radii and after a slow 1/r growth. At these higher concentrations, the coefficients also reveal liquid-like structural effects on pair mobility at close separations. These results confirm that long-range many-body hydrodynamic interactions are an essential part of the dynamics of concentrated systems and that care must be taken when applying renormalization schemes.

  1. Pair mobility functions for rigid spheres in concentrated colloidal dispersions: Force, torque, translation, and rotation

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

    Zia, Roseanna N., E-mail: zia@cbe.cornell.edu; Su, Yu; Swan, James W.

    2015-12-14

    The formulation of detailed models for the dynamics of condensed soft matter including colloidal suspensions and other complex fluids requires accurate description of the physical forces between microstructural constituents. In dilute suspensions, pair-level interactions are sufficient to capture hydrodynamic, interparticle, and thermodynamic forces. In dense suspensions, many-body interactions must be considered. Prior analytical approaches to capturing such interactions such as mean-field approaches replace detailed interactions with averaged approximations. However, long-range coupling and effects of concentration on local structure, which may play an important role in, e.g., phase transitions, are smeared out in such approaches. An alternative to such approximations ismore » the detailed modeling of hydrodynamic interactions utilizing precise couplings between moments of the hydrodynamic traction on a suspended particle and the motion of that or other suspended particles. For two isolated spheres, a set of these functions was calculated by Jeffrey and Onishi [J. Fluid Mech. 139, 261–290 (1984)] and Jeffrey [J. Phys. Fluids 4, 16–29 (1992)]. Along with pioneering work by Batchelor, these are the touchstone for low-Reynolds-number hydrodynamic interactions and have been applied directly in the solution of many important problems related to the dynamics of dilute colloidal dispersions [G. K. Batchelor and J. T. Green, J. Fluid Mech. 56, 375–400 (1972) and G. K. Batchelor, J. Fluid Mech. 74, 1–29 (1976)]. Toward extension of these functions to concentrated systems, here we present a new stochastic sampling technique to rapidly calculate an analogous set of mobility functions describing the hydrodynamic interactions between two hard spheres immersed in a suspension of arbitrary concentration, utilizing accelerated Stokesian dynamics simulations. These mobility functions provide precise, radially dependent couplings of hydrodynamic force and torque to particle translation and rotation, for arbitrary colloid volume fraction ϕ. The pair mobilities (describing entrainment of one particle by the disturbance flow created by another) decay slowly with separation distance: as 1/r, for volume fractions 0.05 ≤ ϕ ≤ 0.5. For the relative mobility, we find an initially rapid growth as a pair separates, followed by a slow, 1/r growth. Up to ϕ ≤ 0.4, the relative mobility does not reached the far-field value even beyond separations of many particle sizes. In the case of ϕ = 0.5, the far-field asymptote is reached but only at a separation of eight radii and after a slow 1/r growth. At these higher concentrations, the coefficients also reveal liquid-like structural effects on pair mobility at close separations. These results confirm that long-range many-body hydrodynamic interactions are an essential part of the dynamics of concentrated systems and that care must be taken when applying renormalization schemes.« less

  2. Exact solutions for a type of electron pairing model with spin-orbit interactions and Zeeman coupling.

    PubMed

    Liu, Jia; Han, Qiang; Shao, L B; Wang, Z D

    2011-07-08

    A type of electron pairing model with spin-orbit interactions or Zeeman coupling is solved exactly in the framework of the Richardson ansatz. Based on the exact solutions for the case with spin-orbit interactions, it is shown rigorously that the pairing symmetry is of the p + ip wave and the ground state possesses time-reversal symmetry, regardless of the strength of the pairing interaction. Intriguingly, how Majorana fermions can emerge in the system is also elaborated. Exact results are illustrated for two systems, respectively, with spin-orbit interactions and Zeeman coupling.

  3. Cooper-pair-condensate fluctuations and plasmons in layered superconductors

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

    Cote, R.; Griffin, A.

    1993-10-01

    Starting from a given attractive potential, we give a systematic analysis of the spin-singlet [ital s]-wave Cooper-pair-condensate fluctuations in a two-dimensional (2D) superconductor. These results are applied to a superlattice of superconducting sheets in which the 2D charge fluctuations are coupled via the Coulomb interaction. Our main interest is how the low-energy Anderson-Bogoliubov (AB) phonon mode in the pair-breaking gap [omega][lt]2[Delta] is modified by the Coulomb interaction. Our formal analysis is valid at arbitrary temperatures. It describes the weakly bound, large-Cooper-pair limit as well as the strongly bound, small-Cooper-pair limit and thus includes both the BCS and Bose-Einstein scenarios (asmore » discussed by Nozieres and Schmitt-Rink as well as Randeira [ital et] [ital al].). A comlete normal-mode analysis is given for a charged BCS superconductor, showing how the repulsive (Coulomb) interaction modifies the collective modes of a neutral superconductor. This complements the recent numerical study carried out by Fertig and Das Sarma. We show that the pair-response function shares the same spectrum as the charge-response function, given by the zero of the longitudinal dielectric function [epsilon]([bold q],[omega]). In 2D and layered superconductors, there is a low-frequency and high-frequency plasmon branch, separated by a relatively narrow particle-hole continuum at around 2[Delta]. The low-frequency ([omega][lt]2[Delta]) plasmon branch is a renormalized version of the AB phonon mode.« less

  4. Maximizing the significance in Higgs boson pair analyses [Mad-Maximized Higgs Pair Analyses

    DOE PAGES

    Kling, Felix; Plehn, Tilman; Schichtel, Peter

    2017-02-22

    Here, we study Higgs pair production with a subsequent decay to a pair of photons and a pair of bottoms at the LHC. We use the log-likelihood ratio to identify the kinematic regions which either allow us to separate the di-Higgs signal from backgrounds or to determine the Higgs self-coupling. We find that both regions are separate enough to ensure that details of the background modeling will not affect the determination of the self-coupling. Assuming dominant statistical uncertainties we determine the best precision with which the Higgs self-coupling can be probed in this channel. We finally comment on the samemore » questions at a future 100 TeV collider.« less

  5. Maximizing the significance in Higgs boson pair analyses [Mad-Maximized Higgs Pair Analyses

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

    Kling, Felix; Plehn, Tilman; Schichtel, Peter

    Here, we study Higgs pair production with a subsequent decay to a pair of photons and a pair of bottoms at the LHC. We use the log-likelihood ratio to identify the kinematic regions which either allow us to separate the di-Higgs signal from backgrounds or to determine the Higgs self-coupling. We find that both regions are separate enough to ensure that details of the background modeling will not affect the determination of the self-coupling. Assuming dominant statistical uncertainties we determine the best precision with which the Higgs self-coupling can be probed in this channel. We finally comment on the samemore » questions at a future 100 TeV collider.« less

  6. Ab initio multireference study of the BN molecule

    NASA Technical Reports Server (NTRS)

    Martin, J. M. L.; Lee, Timothy J.; Scuseria, Gustavo E.; Taylor, Peter R.

    1992-01-01

    The lowest 1Sigma(+) and 3Pi states of the BN molecule are studied using multireference configuration interaction (MRCI) and averaged coupled-pair functional (ACPF) methods and large atomic natural orbital (ANO) basis sets, as well as several coupled cluster methods. Our calculations strongly support a 3Pi ground state, but the a1Sigma(+) state lies only 381 +/- 100/cm higher. The a1Sigma(+) state wave function exhibits strong multireference character and, consequently, the predictions of the perturbationally-based single-reference CCSD(T) coupled cluster method are not as reliable in this case as the multireference results. The theoretical predictions for the spectroscopic constants of BN are in good agreement with experiment for the Chi3Pi state, but strongly suggest a misassignment of the fundamental vibrational frequency for the a1Sigma(+) state.

  7. Multiconfiguration pair-density functional theory investigation of the electronic spectrum of MnO4-

    NASA Astrophysics Data System (ADS)

    Sharma, Prachi; Truhlar, Donald G.; Gagliardi, Laura

    2018-03-01

    The electronic spectrum of permanganate ions contains various highly multiconfigurational ligand-to-metal charge transfer states and is notorious for being one of the most challenging systems to be treated by quantum-chemical methods. Here we studied the lowest nine vertical excitation energies using restricted active space second-order perturbation theory (RASPT2) and multiconfiguration pair-density functional theory (MC-PDFT) to test and compare these two theories in computing such a challenging spectrum. The results are compared to literature data, including time-dependent density functional theory, completely renormalized equation-of-motion couple-cluster theory with single and double excitations, symmetry-adapted-cluster configuration interaction, and experimental spectra in the gas phase and solution. Our results show that MC-PDFT accurately predicts the spectrum at a significantly reduced cost as compared to RASPT2.

  8. Multiconfiguration pair-density functional theory investigation of the electronic spectrum of MnO4.

    PubMed

    Sharma, Prachi; Truhlar, Donald G; Gagliardi, Laura

    2018-03-28

    The electronic spectrum of permanganate ions contains various highly multiconfigurational ligand-to-metal charge transfer states and is notorious for being one of the most challenging systems to be treated by quantum-chemical methods. Here we studied the lowest nine vertical excitation energies using restricted active space second-order perturbation theory (RASPT2) and multiconfiguration pair-density functional theory (MC-PDFT) to test and compare these two theories in computing such a challenging spectrum. The results are compared to literature data, including time-dependent density functional theory, completely renormalized equation-of-motion couple-cluster theory with single and double excitations, symmetry-adapted-cluster configuration interaction, and experimental spectra in the gas phase and solution. Our results show that MC-PDFT accurately predicts the spectrum at a significantly reduced cost as compared to RASPT2.

  9. Pairing-induced speedup of nuclear spontaneous fission

    NASA Astrophysics Data System (ADS)

    Sadhukhan, Jhilam; Dobaczewski, J.; Nazarewicz, W.; Sheikh, J. A.; Baran, A.

    2014-12-01

    Background: Collective inertia is strongly influenced at the level crossing at which the quantum system changes its microscopic configuration diabatically. Pairing correlations tend to make the large-amplitude nuclear collective motion more adiabatic by reducing the effect of these configuration changes. Competition between pairing and level crossing is thus expected to have a profound impact on spontaneous fission lifetimes. Purpose: To elucidate the role of nucleonic pairing on spontaneous fission, we study the dynamic fission trajectories of 264Fm and 240Pu using the state-of-the-art self-consistent framework. Methods: We employ the superfluid nuclear density functional theory with the Skyrme energy density functional SkM* and a density-dependent pairing interaction. Along with shape variables, proton and neutron pairing correlations are taken as collective coordinates. The collective inertia tensor is calculated within the nonperturbative cranking approximation. The fission paths are obtained by using the least action principle in a four-dimensional collective space of shape and pairing coordinates. Results: Pairing correlations are enhanced along the minimum-action fission path. For the symmetric fission of 264Fm, where the effect of triaxiality on the fission barrier is large, the geometry of the fission pathway in the space of the shape degrees of freedom is weakly impacted by pairing. This is not the case for 240Pu, where pairing fluctuations restore the axial symmetry of the dynamic fission trajectory. Conclusions: The minimum-action fission path is strongly impacted by nucleonic pairing. In some cases, the dynamical coupling between shape and pairing degrees of freedom can lead to a dramatic departure from the static picture. Consequently, in the dynamical description of nuclear fission, particle-particle correlations should be considered on the same footing as those associated with shape degrees of freedom.

  10. Pairing-induced speedup of nuclear spontaneous fission

    DOE PAGES

    Sadhukhan, Jhilam; Dobaczewski, J.; Nazarewicz, W.; ...

    2014-12-22

    Collective inertia is strongly influenced at the level crossing at which the quantum system changes its microscopic configuration diabatically. Pairing correlations tend to make the large-amplitude nuclear collective motion more adiabatic by reducing the effect of these configuration changes. Competition between pairing and level crossing is thus expected to have a profound impact on spontaneous fission lifetimes. To elucidate the role of nucleonic pairing on spontaneous fission, we study the dynamic fission trajectories of 264Fm and 240Pu using the state-of-the-art self-consistent framework. We employ the superfluid nuclear density functional theory with the Skyrme energy density functional SkM* and a density-dependentmore » pairing interaction. Along with shape variables, proton and neutron pairing correlations are taken as collective coordinates. The collective inertia tensor is calculated within the nonperturbative cranking approximation. The fission paths are obtained by using the least action principle in a four-dimensional collective space of shape and pairing coordinates. Pairing correlations are enhanced along the minimum-action fission path. For the symmetric fission of 264Fm, where the effect of triaxiality on the fission barrier is large, the geometry of the fission pathway in the space of the shape degrees of freedom is weakly impacted by pairing. This is not the case for 240Pu, where pairing fluctuations restore the axial symmetry of the dynamic fission trajectory. The minimum-action fission path is strongly impacted by nucleonic pairing. In some cases, the dynamical coupling between shape and pairing degrees of freedom can lead to a dramatic departure from the static picture. As a result, in the dynamical description of nuclear fission, particle-particle correlations should be considered on the same footing as those associated with shape degrees of freedom.« less

  11. Systematic and simulation-free coarse graining of homopolymer melts: a relative-entropy-based study.

    PubMed

    Yang, Delian; Wang, Qiang

    2015-09-28

    We applied the systematic and simulation-free strategy proposed in our previous work (D. Yang and Q. Wang, J. Chem. Phys., 2015, 142, 054905) to the relative-entropy-based (RE-based) coarse graining of homopolymer melts. RE-based coarse graining provides a quantitative measure of the coarse-graining performance and can be used to select the appropriate analytic functional forms of the pair potentials between coarse-grained (CG) segments, which are more convenient to use than the tabulated (numerical) CG potentials obtained from structure-based coarse graining. In our general coarse-graining strategy for homopolymer melts using the RE framework proposed here, the bonding and non-bonded CG potentials are coupled and need to be solved simultaneously. Taking the hard-core Gaussian thread model (K. S. Schweizer and J. G. Curro, Chem. Phys., 1990, 149, 105) as the original system, we performed RE-based coarse graining using the polymer reference interaction site model theory under the assumption that the intrachain segment pair correlation functions of CG systems are the same as those in the original system, which de-couples the bonding and non-bonded CG potentials and simplifies our calculations (that is, we only calculated the latter). We compared the performance of various analytic functional forms of non-bonded CG pair potential and closures for CG systems in RE-based coarse graining, as well as the structural and thermodynamic properties of original and CG systems at various coarse-graining levels. Our results obtained from RE-based coarse graining are also compared with those from structure-based coarse graining.

  12. Transfer impedances of balanced shielded cables

    NASA Astrophysics Data System (ADS)

    Hardiguian, M.

    1982-07-01

    The transfer impedance concept is extended to balanced shielded cables, e.g., shielded pairs and twinax in which the actual voltage developed at the load, between the two wires of a pair is emphasized. This parameter can be computed by a separate knowledge of the shield, and the shield-to-pair coupling (i.e., the pair unbalance ratio). Thus, a unique parameter called shield coupling evolves which relates directly the shield current to the differential output voltage. Conditions of cable pair and harness shielding and the impact of grounding at one or both ends are discussed.

  13. Approximate solution of the mode-mode coupling integral: Application to cytosine and its deuterated derivative.

    PubMed

    Rasheed, Tabish; Ahmad, Shabbir

    2010-10-01

    Ab initio Hartree-Fock (HF), density functional theory (DFT) and second-order Møller-Plesset (MP2) methods were used to perform harmonic and anharmonic calculations for the biomolecule cytosine and its deuterated derivative. The anharmonic vibrational spectra were computed using the vibrational self-consistent field (VSCF) and correlation-corrected vibrational self-consistent field (CC-VSCF) methods. Calculated anharmonic frequencies have been compared with the argon matrix spectra reported in literature. The results were analyzed with focus on the properties of anharmonic couplings between pair of modes. A simple and easy to use formula for calculation of mode-mode coupling magnitudes has been derived. The key element in present approach is the approximation that only interactions between pairs of normal modes have been taken into account, while interactions of triples or more are neglected. FTIR and Raman spectra of solid state cytosine have been recorded in the regions 400-4000 cm(-1) and 60-4000 cm(-1), respectively. Vibrational analysis and assignments are based on calculated potential energy distribution (PED) values. Copyright 2010 Elsevier B.V. All rights reserved.

  14. Why do some women prefer submissive men? Hierarchically disparate couples reach higher reproductive success in European urban humans.

    PubMed

    Jozifkova, Eva; Konvicka, Martin; Flegr, Jaroslav

    2014-01-01

    Equality between partners is considering a feature of the functional partnerships in westernized societies. However, the evolutionary consequences of how in-pair hierarchy influences reproduction are less known. Attraction of some high-ranking women towards low-ranking men represents a puzzle. Young urban adults (120 men, 171 women) filled out a questionnaire focused on their sexual preference for higher or lower ranking partners, their future in-pair hierarchy, and hierarchy between their parents. Human pairs with a hierarchic disparity between partners conceive more offspring than pairs of equally-ranking individuals, who, in turn, conceive more offspring than pairs of two dominating partners. Importantly, the higher reproductive success of hierarchically disparate pairs holds, regardless of which sex, male or female, is the dominant one. In addition, the subjects preferring hierarchy disparity in partnerships were with greater probability sexually aroused by such disparity, suggesting that both the partnership preference and the triggers of sexual arousal may reflect a mating strategy. These results challenge the frequently held belief in within-pair equality as a trademark of functional partnerships. It rather appears that existence of some disparity improves within-pair cohesion, facilitating both cooperation between partners and improving the pairs' ability to face societal challenges. The parallel existence of submissivity-dominance hierarchies within human sexes allows for the parallel existence of alternative reproductive strategies, and may form a background for the diversity of mating systems observed in human societies. Arousal of overemphasized dominance/submissiveness may explain sadomasochistic sex, still little understood from the evolutionary psychology point of view.

  15. Charged particle layers in the Debye limit.

    PubMed

    Golden, Kenneth I; Kalman, Gabor J; Kyrkos, Stamatios

    2002-09-01

    We develop an equivalent of the Debye-Hückel weakly coupled equilibrium theory for layered classical charged particle systems composed of one single charged species. We consider the two most important configurations, the charged particle bilayer and the infinite superlattice. The approach is based on the link provided by the classical fluctuation-dissipation theorem between the random-phase approximation response functions and the Debye equilibrium pair correlation function. Layer-layer pair correlation functions, screened and polarization potentials, static structure functions, and static response functions are calculated. The importance of the perfect screening and compressibility sum rules in determining the overall behavior of the system, especially in the r--> infinity limit, is emphasized. The similarities and differences between the quasi-two-dimensional bilayer and the quasi-three-dimensional superlattice are highlighted. An unexpected behavior that emerges from the analysis is that the screened potential, the correlations, and the screening charges carried by the individual layers exhibit a marked nonmonotonic dependence on the layer separation.

  16. Peculiarities of the momentum distribution functions of strongly correlated charged fermions

    NASA Astrophysics Data System (ADS)

    Larkin, A. S.; Filinov, V. S.; Fortov, V. E.

    2018-01-01

    New numerical version of the Wigner approach to quantum thermodynamics of strongly coupled systems of particles has been developed for extreme conditions, when analytical approximations based on different kinds of perturbation theories cannot be applied. An explicit analytical expression of the Wigner function has been obtained in linear and harmonic approximations. Fermi statistical effects are accounted for by effective pair pseudopotential depending on coordinates, momenta and degeneracy parameter of particles and taking into account Pauli blocking of fermions. A new quantum Monte-Carlo method for calculations of average values of arbitrary quantum operators has been developed. Calculations of the momentum distribution functions and the pair correlation functions of degenerate ideal Fermi gas have been carried out for testing the developed approach. Comparison of the obtained momentum distribution functions of strongly correlated Coulomb systems with the Maxwell-Boltzmann and the Fermi distributions shows the significant influence of interparticle interaction both at small momenta and in high energy quantum ‘tails’.

  17. Comparative study of the effectiveness and limitations of current methods for detecting sequence coevolution.

    PubMed

    Mao, Wenzhi; Kaya, Cihan; Dutta, Anindita; Horovitz, Amnon; Bahar, Ivet

    2015-06-15

    With rapid accumulation of sequence data on several species, extracting rational and systematic information from multiple sequence alignments (MSAs) is becoming increasingly important. Currently, there is a plethora of computational methods for investigating coupled evolutionary changes in pairs of positions along the amino acid sequence, and making inferences on structure and function. Yet, the significance of coevolution signals remains to be established. Also, a large number of false positives (FPs) arise from insufficient MSA size, phylogenetic background and indirect couplings. Here, a set of 16 pairs of non-interacting proteins is thoroughly examined to assess the effectiveness and limitations of different methods. The analysis shows that recent computationally expensive methods designed to remove biases from indirect couplings outperform others in detecting tertiary structural contacts as well as eliminating intermolecular FPs; whereas traditional methods such as mutual information benefit from refinements such as shuffling, while being highly efficient. Computations repeated with 2,330 pairs of protein families from the Negatome database corroborated these results. Finally, using a training dataset of 162 families of proteins, we propose a combined method that outperforms existing individual methods. Overall, the study provides simple guidelines towards the choice of suitable methods and strategies based on available MSA size and computing resources. Software is freely available through the Evol component of ProDy API. © The Author 2015. Published by Oxford University Press.

  18. Effect of proton transfer on the electronic coupling in DNA

    NASA Astrophysics Data System (ADS)

    Rak, Janusz; Makowska, Joanna; Voityuk, Alexander A.

    2006-06-01

    The effects of single and double proton transfer within Watson-Crick base pairs on donor-acceptor electronic couplings, Vda, in DNA are studied on the bases of quantum chemical calculations. Four dimers [AT,AT], [GC,GC], [GC,AT] and [GC,TA)] are considered. Three techniques - the generalized Mulliken-Hush scheme, the fragment charge method and the diabatic states method - are employed to estimate Vda for hole transfer between base pairs. We show that both single- and double proton transfer (PT) reactions may substantially affect the electronic coupling in DNA. The electronic coupling in [AT,AT] is predicted to be most sensitive to PT. Single PT within the first base pair in the dimer leads to increase in the hole transfer efficiency by a factor of 4, while proton transfer within the second pair should substantially, by 2.7 times, decrease the rate of charge transfer. Thus, directional asymmetry of the PT effects on the electronic coupling is predicted. The changes in the Vda matrix elements correlate with the topological properties of orbitals of donor and acceptor and can be qualitatively rationalized in terms of resonance structures of donor and acceptor. Atomic pair contributions to the Vda matrix elements are also analyzed.

  19. Photon pair source via two coupling single quantum emitters

    NASA Astrophysics Data System (ADS)

    Peng, Yong-Gang; Zheng, Yu-Jun

    2015-10-01

    We study the two coupling two-level single molecules driven by an external field as a photon pair source. The probability of emitting two photons, P2, is employed to describe the photon pair source quality in a short time, and the correlation coefficient RAB is employed to describe the photon pair source quality in a long time limit. The results demonstrate that the coupling single quantum emitters can be considered as a stable photon pair source. Project supported by the National Natural Science Foundation of China (Grand Nos. 91021009, 21073110, and 11374191), the Natural Science Foundation of Shandong Province, China (Grant No. ZR2013AQ020), the Postdoctoral Science Foundation of China (Grant No. 2013M531584), the Doctoral Program of Higher Education of China (Grant Nos. 20130131110005 and 20130131120006), and the Taishan Scholarship Project of Shandong Province, China.

  20. State-of-the-art ab initio potential energy curve for the krypton atom pair and thermophysical properties of dilute krypton gas

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

    Jäger, Benjamin, E-mail: benjamin.jaeger@uni-rostock.de; Hellmann, Robert, E-mail: robert.hellmann@uni-rostock.de; Bich, Eckard

    2016-03-21

    A new reference krypton-krypton interatomic potential energy curve was developed by means of quantum-chemical ab initio calculations for 36 interatomic separations. Highly accurate values for the interaction energies at the complete basis set limit were obtained using the coupled-cluster method with single, double, and perturbative triple excitations as well as t-aug-cc-pV5Z and t-aug-cc-pV6Z basis sets including mid-bond functions, with the 6Z basis set being newly constructed for this study. Higher orders of coupled-cluster terms were considered in a successive scheme up to full quadruple excitations. Core-core and core-valence correlation effects were included. Furthermore, relativistic effects were studied not only atmore » a scalar relativistic level using second-order direct perturbation theory, but also utilizing full four-component and Gaunt-effect computations. An analytical pair potential function was fitted to the interaction energies, which is characterized by a depth of 200.88 K with an estimated standard uncertainty of 0.51 K. Thermophysical properties of low-density krypton were calculated for temperatures up to 5000 K. Second and third virial coefficients were obtained from statistical thermodynamics. Viscosity and thermal conductivity as well as the self-diffusion coefficient were computed using the kinetic theory of gases. The theoretical results are compared with experimental data and with results for other pair potential functions from the literature, especially with those calculated from the recently developed ab initio potential of Waldrop et al. [J. Chem. Phys. 142, 204307 (2015)]. Highly accurate experimental viscosity data indicate that both the present ab initio pair potential and the one of Waldrop et al. can be regarded as reference potentials, even though the quantum-chemical methods and basis sets differ. However, the uncertainties of the present potential and of the derived properties are estimated to be considerably lower.« less

  1. State-of-the-art ab initio potential energy curve for the krypton atom pair and thermophysical properties of dilute krypton gas.

    PubMed

    Jäger, Benjamin; Hellmann, Robert; Bich, Eckard; Vogel, Eckhard

    2016-03-21

    A new reference krypton-krypton interatomic potential energy curve was developed by means of quantum-chemical ab initio calculations for 36 interatomic separations. Highly accurate values for the interaction energies at the complete basis set limit were obtained using the coupled-cluster method with single, double, and perturbative triple excitations as well as t-aug-cc-pV5Z and t-aug-cc-pV6Z basis sets including mid-bond functions, with the 6Z basis set being newly constructed for this study. Higher orders of coupled-cluster terms were considered in a successive scheme up to full quadruple excitations. Core-core and core-valence correlation effects were included. Furthermore, relativistic effects were studied not only at a scalar relativistic level using second-order direct perturbation theory, but also utilizing full four-component and Gaunt-effect computations. An analytical pair potential function was fitted to the interaction energies, which is characterized by a depth of 200.88 K with an estimated standard uncertainty of 0.51 K. Thermophysical properties of low-density krypton were calculated for temperatures up to 5000 K. Second and third virial coefficients were obtained from statistical thermodynamics. Viscosity and thermal conductivity as well as the self-diffusion coefficient were computed using the kinetic theory of gases. The theoretical results are compared with experimental data and with results for other pair potential functions from the literature, especially with those calculated from the recently developed ab initio potential of Waldrop et al. [J. Chem. Phys. 142, 204307 (2015)]. Highly accurate experimental viscosity data indicate that both the present ab initio pair potential and the one of Waldrop et al. can be regarded as reference potentials, even though the quantum-chemical methods and basis sets differ. However, the uncertainties of the present potential and of the derived properties are estimated to be considerably lower.

  2. Higgs Pair Production as a Signal of Enhanced Yukawa Couplings

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

    Bauer, Martin; Carena, Marcela; Carmona, Adrián

    We present a non-trivial correlation between the enhancement of the Higgs-fermion couplings and the Higgs pair production cross section in two Higgs doublet models with a flavour symmetry. This symmetry suppresses flavour-changing neutral couplings of the Higgs boson and allows for a partial explanation of the hierarchy in the Yukawa sector. After taking into account the constraints from electroweak precision measurements, Higgs coupling strength measurements, and unitarity and perturbativity bounds, we identify an interesting region of parameter space leading to enhanced Yukawa couplings as well as enhanced di-Higgs gluon fusion production at the LHC reach. This effect is visible inmore » both the resonant and non-resonant contributions to the Higgs pair production cross section. We encourage dedicated searches based on differential distributions as a novel way to indirectly probe enhanced Higgs couplings to light fermions.« less

  3. Frequency-phase analysis of resting-state functional MRI

    PubMed Central

    Goelman, Gadi; Dan, Rotem; Růžička, Filip; Bezdicek, Ondrej; Růžička, Evžen; Roth, Jan; Vymazal, Josef; Jech, Robert

    2017-01-01

    We describe an analysis method that characterizes the correlation between coupled time-series functions by their frequencies and phases. It provides a unified framework for simultaneous assessment of frequency and latency of a coupled time-series. The analysis is demonstrated on resting-state functional MRI data of 34 healthy subjects. Interactions between fMRI time-series are represented by cross-correlation (with time-lag) functions. A general linear model is used on the cross-correlation functions to obtain the frequencies and phase-differences of the original time-series. We define symmetric, antisymmetric and asymmetric cross-correlation functions that correspond respectively to in-phase, 90° out-of-phase and any phase difference between a pair of time-series, where the last two were never introduced before. Seed maps of the motor system were calculated to demonstrate the strength and capabilities of the analysis. Unique types of functional connections, their dominant frequencies and phase-differences have been identified. The relation between phase-differences and time-delays is shown. The phase-differences are speculated to inform transfer-time and/or to reflect a difference in the hemodynamic response between regions that are modulated by neurotransmitters concentration. The analysis can be used with any coupled functions in many disciplines including electrophysiology, EEG or MEG in neuroscience. PMID:28272522

  4. Dispersion correction derived from first principles for density functional theory and Hartree-Fock theory.

    PubMed

    Guidez, Emilie B; Gordon, Mark S

    2015-03-12

    The modeling of dispersion interactions in density functional theory (DFT) is commonly performed using an energy correction that involves empirically fitted parameters for all atom pairs of the system investigated. In this study, the first-principles-derived dispersion energy from the effective fragment potential (EFP) method is implemented for the density functional theory (DFT-D(EFP)) and Hartree-Fock (HF-D(EFP)) energies. Overall, DFT-D(EFP) performs similarly to the semiempirical DFT-D corrections for the test cases investigated in this work. HF-D(EFP) tends to underestimate binding energies and overestimate intermolecular equilibrium distances, relative to coupled cluster theory, most likely due to incomplete accounting for electron correlation. Overall, this first-principles dispersion correction yields results that are in good agreement with coupled-cluster calculations at a low computational cost.

  5. Magnetic quasi-long-range ordering in nematic systems due to competition between higher-order couplings

    NASA Astrophysics Data System (ADS)

    Žukovič, Milan; Kalagov, Georgii

    2018-05-01

    Critical properties of the two-dimensional X Y model involving solely nematic-like terms of the second and third orders are investigated by spin-wave analysis and Monte Carlo simulation. It is found that, even though neither of the nematic-like terms alone can induce magnetic ordering, their coexistence and competition leads to an extended phase of the magnetic quasi-long-range-order phase, wedged between the two nematic-like phases induced by the respective couplings. Thus, except for the multicritical point, at which all the phases meet, for any finite value of the coupling parameters ratio there are two phase transition: one from the paramagnetic phase to one of the two nematic-like phases followed by another one at lower temperatures to the magnetic phase. The finite-size scaling analysis indicates that the phase transitions between the magnetic and nematic-like phases belong to the Ising and three-state Potts universality classes. Inside the competition-induced algebraic magnetic phase, the spin-pair correlation function is found to decay even much more slowly than in the standard X Y model with purely magnetic interactions. Such a magnetic phase is characterized by an extremely low vortex-antivortex pair density attaining a minimum close to the point at which the two couplings are of about equal strength.

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

    Gomez, John A.; Henderson, Thomas M.; Scuseria, Gustavo E.

    Restricted single-reference coupled cluster theory truncated to single and double excitations accurately describes weakly correlated systems, but often breaks down in the presence of static or strong correlation. Good coupled cluster energies in the presence of degeneracies can be obtained by using a symmetry-broken reference, such as unrestricted Hartree-Fock, but at the cost of good quantum numbers. A large body of work has shown that modifying the coupled cluster ansatz allows for the treatment of strong correlation within a single-reference, symmetry-adapted framework. The recently introduced singlet-paired coupled cluster doubles (CCD0) method is one such model, which recovers correct behavior formore » strong correlation without requiring symmetry breaking in the reference. Here, we extend singlet-paired coupled cluster for application to open shells via restricted open-shell singlet-paired coupled cluster singles and doubles (ROCCSD0). The ROCCSD0 approach retains the benefits of standard coupled cluster theory and recovers correct behavior for strongly correlated, open-shell systems using a spin-preserving ROHF reference.« less

  7. Sparse networks of directly coupled, polymorphic, and functional side chains in allosteric proteins.

    PubMed

    Soltan Ghoraie, Laleh; Burkowski, Forbes; Zhu, Mu

    2015-03-01

    Recent studies have highlighted the role of coupled side-chain fluctuations alone in the allosteric behavior of proteins. Moreover, examination of X-ray crystallography data has recently revealed new information about the prevalence of alternate side-chain conformations (conformational polymorphism), and attempts have been made to uncover the hidden alternate conformations from X-ray data. Hence, new computational approaches are required that consider the polymorphic nature of the side chains, and incorporate the effects of this phenomenon in the study of information transmission and functional interactions of residues in a molecule. These studies can provide a more accurate understanding of the allosteric behavior. In this article, we first present a novel approach to generate an ensemble of conformations and an efficient computational method to extract direct couplings of side chains in allosteric proteins, and provide sparse network representations of the couplings. We take the side-chain conformational polymorphism into account, and show that by studying the intrinsic dynamics of an inactive structure, we are able to construct a network of functionally crucial residues. Second, we show that the proposed method is capable of providing a magnified view of the coupled and conformationally polymorphic residues. This model reveals couplings between the alternate conformations of a coupled residue pair. To the best of our knowledge, this is the first computational method for extracting networks of side chains' alternate conformations. Such networks help in providing a detailed image of side-chain dynamics in functionally important and conformationally polymorphic sites, such as binding and/or allosteric sites. © 2014 Wiley Periodicals, Inc.

  8. Accurate, precise, and efficient theoretical methods to calculate anion-π interaction energies in model structures.

    PubMed

    Mezei, Pál D; Csonka, Gábor I; Ruzsinszky, Adrienn; Sun, Jianwei

    2015-01-13

    A correct description of the anion-π interaction is essential for the design of selective anion receptors and channels and important for advances in the field of supramolecular chemistry. However, it is challenging to do accurate, precise, and efficient calculations of this interaction, which are lacking in the literature. In this article, by testing sets of 20 binary anion-π complexes of fluoride, chloride, bromide, nitrate, or carbonate ions with hexafluorobenzene, 1,3,5-trifluorobenzene, 2,4,6-trifluoro-1,3,5-triazine, or 1,3,5-triazine and 30 ternary π-anion-π' sandwich complexes composed from the same monomers, we suggest domain-based local-pair natural orbital coupled cluster energies extrapolated to the complete basis-set limit as reference values. We give a detailed explanation of the origin of anion-π interactions, using the permanent quadrupole moments, static dipole polarizabilities, and electrostatic potential maps. We use symmetry-adapted perturbation theory (SAPT) to calculate the components of the anion-π interaction energies. We examine the performance of the direct random phase approximation (dRPA), the second-order screened exchange (SOSEX), local-pair natural-orbital (LPNO) coupled electron pair approximation (CEPA), and several dispersion-corrected density functionals (including generalized gradient approximation (GGA), meta-GGA, and double hybrid density functional). The LPNO-CEPA/1 results show the best agreement with the reference results. The dRPA method is only slightly less accurate and precise than the LPNO-CEPA/1, but it is considerably more efficient (6-17 times faster) for the binary complexes studied in this paper. For 30 ternary π-anion-π' sandwich complexes, we give dRPA interaction energies as reference values. The double hybrid functionals are much more efficient but less accurate and precise than dRPA. The dispersion-corrected double hybrid PWPB95-D3(BJ) and B2PLYP-D3(BJ) functionals perform better than the GGA and meta-GGA functionals for the present test set.

  9. Understanding The Role of Mate Selection Processes in Couples' Pair-Bonding Behavior.

    PubMed

    Horwitz, Briana N; Reynolds, Chandra A; Walum, Hasse; Ganiban, Jody; Spotts, Erica L; Reiss, David; Lichtenstein, Paul; Neiderhiser, Jenae M

    2016-01-01

    Couples are similar in their pair-bonding behavior, yet the reasons for this similarity are often unclear. A common explanation is phenotypic assortment, whereby individuals select partners with similar heritable characteristics. Alternatively, social homogamy, whereby individuals passively select partners with similar characteristic due to shared social backgrounds, is rarely considered. We examined whether phenotypic assortment and/or social homogamy can contribute to mate similarity using a twin-partner design. The sample came from the Twin and Offspring Study in Sweden, which included 876 male and female monozygotic and same-sex dizygotic twins plus their married or cohabitating partners. Results showed that variance in pair-bonding behavior was attributable to genetic and nonshared environmental factors. Furthermore, phenotypic assortment accounted for couple similarity in pair-bonding behavior. This suggests that individuals' genetically based characteristics are involved in their selection of mates with similar pair-bonding behavior.

  10. Kinematic analysis of articulatory coupling in acquired apraxia of speech post-stroke.

    PubMed

    Bartle-Meyer, Carly J; Goozée, Justine V; Murdoch, Bruce E; Green, Jordan R

    2009-02-01

    Electromagnetic articulography was employed to investigate the strength of articulatory coupling and hence the degree of functional movement independence between individual articulators in apraxia of speech (AOS). Tongue-tip, tongue-back and jaw movement was recorded from five speakers with AOS and a concomitant aphasia (M = 53.6 years; SD = 12.60) during /ta, sa, la, ka/ syllable repetitions, spoken at typical and fast rates of speech. Covariance values were calculated for each articulatory pair to gauge the strength of articulatory coupling. The results obtained for each of the participants with AOS were individually compared to those obtained by a control group (n = 12; M = 52.08 years; SD = 12.52). Comparisons were made between the typical rate productions of the control group and the typical and fast rate productions of the participants with AOS. In comparison to the control group, four speakers with AOS exhibited significantly stronger articulatory coupling for alveolar and/or velar speech targets, during typical and/or fast rate conditions, suggesting decreased functional movement independence. The reduction in functional movement independence might have reflected an attempt to simplify articulatory control or a decrease in the ability to differentially control distinct articulatory regions.

  11. What couples say about their recovery of sexual intimacy after prostatectomy: toward the development of a conceptual model of couples’ sexual recovery after surgery for prostate cancer

    PubMed Central

    Wittmann, Daniela; Carolan, Marsha; Given, Barbara; Skolarus, Ted A.; Crossley, Heather; An, Lawrence; Palapattu, Ganesh; Clark, Patricia; Montie, James E.

    2015-01-01

    Introduction Interventions designed to help couples recover sexual intimacy after prostatectomy have not been guided by a comprehensive conceptual model. Aim We examined a proposed biopsychosocial conceptual model of couples’ sexual recovery that included functional, psychological and relational aspects of sexuality, surgery-related sexual losses, and grief and mourning as recovery process. Methods We interviewed twenty couples pre-operatively and 3-months post-operatively. between 2010 and 2012. Interviews were analyzed with Analytic Induction qualitative methodology, using NVivo software. Paired t-tests described functional assessment data. Study findings led to a revised conceptual model. Main Outcome Measures Couples’ experiences were assessed through semi-structured interviews; male participants’ sexual function was assessed with the Expanded Prostate Cancer Index Composite and female participants’ sexual function with the Female Sexual Function Index. Results Pre-operatively, 30% of men had erectile dysfunction (ED), 84% of partners were post-menopausal. All valued sexual recovery, but worried about cancer spread and surgery side-effects. Faith in themselves and their surgeons led 90% of couples to overestimate erectile recovery. Post-operatively, most men had ED and lost confidence. Couples’ sexual activity decreased. Couples reported feeling loss and grief: cancer diagnosis was the first loss, followed by surgery-related sexual losses. Couples’ engagement in intentional sex, patients’ acceptance of erectile aids and partners’ interest in sex aided the recovery of couples’ sexual intimacy recovery. Unselfconscious sex, not return to erectile function baseline, was seen as the endpoint. Survey findings documented participants’ sexual function losses, confirming qualitative findings. Conclusions Couples’ sexual recovery requires addressing sexual function, feelings about losses and relationship simultaneously. Peri-operative education should emphasize the roles of nerve damage in ED and grief and mourning in sexual recovery. PMID:25358901

  12. Majorana edge States in atomic wires coupled by pair hopping.

    PubMed

    Kraus, Christina V; Dalmonte, Marcello; Baranov, Mikhail A; Läuchli, Andreas M; Zoller, P

    2013-10-25

    We present evidence for Majorana edge states in a number conserving theory describing a system of spinless fermions on two wires that are coupled by pair hopping. Our analysis is based on a combination of a qualitative low energy approach and numerical techniques using the density matrix renormalization group. In addition, we discuss an experimental realization of pair-hopping interactions in cold atom gases confined in optical lattices.

  13. Boson mapping techniques applied to constant gauge fields in QCD

    NASA Technical Reports Server (NTRS)

    Hess, Peter Otto; Lopez, J. C.

    1995-01-01

    Pairs of coordinates and derivatives of the constant gluon modes are mapped to new gluon-pair fields and their derivatives. Applying this mapping to the Hamiltonian of constant gluon fields results for large coupling constants into an effective Hamiltonian which separates into one describing a scalar field and another one for a field with spin two. The ground state is dominated by pairs of gluons coupled to color and spin zero with slight admixtures of color zero and spin two pairs. As color group we used SU(2).

  14. Dynamics and couplings of N-H stretching excitations of guanosine-cytidine base pairs in solution.

    PubMed

    Yang, Ming; Szyc, Łukasz; Röttger, Katharina; Fidder, Henk; Nibbering, Erik T J; Elsaesser, Thomas; Temps, Friedrich

    2011-05-12

    N-H stretching vibrations of hydrogen-bonded guanosine-cytidine (G·C) base pairs in chloroform solution are studied with linear and ultrafast nonlinear infrared (IR) spectroscopy. Assignment of the IR-active bands in the linear spectrum is made possible by combining structural information on the hydrogen bonds in G·C base pairs with literature results of density functional theory calculations, and empirical relations connecting frequency shifts and intensity of the IR-active vibrations. A local mode representation of N-H stretching vibrations is adopted, consisting of ν(G)(NH(2))(f) and ν(C)(NH(2))(f) modes for free NH groups of G and C, and of ν(G)(NH(2))(b), ν(G)(NH), and ν(C)(NH(2))(b) modes associated with N-H stretching motions of hydrogen-bonded NH groups. The couplings and relaxation dynamics of the N-H stretching excitations are studied with femtosecond mid-infrared two-dimensional (2D) and pump-probe spectroscopy. The N-H stretching vibrations of the free NH groups of G and C have an average population lifetime of 2.4 ps. Besides a vibrational population lifetime shortening to subpicosecond values observed for the hydrogen-bonded N-H stretching vibrations, the 2D spectra reveal vibrational excitation transfer from the ν(G)(NH(2))(b) mode to the ν(G)(NH) and/or ν(C)(NH(2))(b) modes. The underlying intermode vibrational couplings are on the order of 10 cm(-1).

  15. Common Coupled Fixed Point Theorems for Two Hybrid Pairs of Mappings under φ-ψ Contraction

    PubMed Central

    Handa, Amrish

    2014-01-01

    We introduce the concept of (EA) property and occasional w-compatibility for hybrid pair F : X × X → 2X and f : X → X. We also introduce common (EA) property for two hybrid pairs F, G : X → 2X and f, g : X → X. We establish some common coupled fixed point theorems for two hybrid pairs of mappings under φ-ψ contraction on noncomplete metric spaces. An example is also given to validate our results. We improve, extend and generalize several known results. The results of this paper generalize the common fixed point theorems for hybrid pairs of mappings and essentially contain fixed point theorems for hybrid pair of mappings. PMID:27340688

  16. Extraction of the gate capacitance coupling coefficient in floating gate non-volatile memories: Statistical study of the effect of mismatching between floating gate memory and reference transistor in dummy cell extraction methods

    NASA Astrophysics Data System (ADS)

    Rafhay, Quentin; Beug, M. Florian; Duane, Russell

    2007-04-01

    This paper presents an experimental comparison of dummy cell extraction methods of the gate capacitance coupling coefficient for floating gate non-volatile memory structures from different geometries and technologies. These results show the significant influence of mismatching floating gate devices and reference transistors on the extraction of the gate capacitance coupling coefficient. In addition, it demonstrates the accuracy of the new bulk bias dummy cell extraction method and the importance of the β function, introduced recently in [Duane R, Beug F, Mathewson A. Novel capacitance coupling coefficient measurement methodology for floating gate non-volatile memory devices. IEEE Electr Dev Lett 2005;26(7):507-9], to determine matching pairs of floating gate memory and reference transistor.

  17. Pairing tendencies in a two-orbital Hubbard model in one dimension

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

    Patel, Niravkumar D.; Nocera, Adriana; Alvarez, Gonzalo

    The recent discovery of superconductivity under high pressure in the ladder compound BaFe2S3 has opened a new field of research in iron-based superconductors with focus on quasi-one-dimensional geometries. In this publication, using the density matrix renormalization group technique, we study a two-orbital Hubbard model defined in one-dimensional chains. Our main result is the presence of hole binding tendencies at intermediate Hubbard U repulsion and robust Hund coupling JH / U = 0.25. Binding does not occur either in weak coupling or at very strong coupling. The pair-pair correlations that are dominant near half-filling, or of similar strength as the chargemore » and spin correlation channels, involve hole-pair operators that are spin singlets, use nearest-neighbor sites, and employ different orbitals for each hole. As a result, the Hund coupling strength, presence of robust magnetic moments, and antiferromagnetic correlations among them are important for the binding tendencies found here.« less

  18. Nuclear quantum shape-phase transitions in odd-mass systems

    NASA Astrophysics Data System (ADS)

    Quan, S.; Li, Z. P.; Vretenar, D.; Meng, J.

    2018-03-01

    Microscopic signatures of nuclear ground-state shape-phase transitions in odd-mass Eu isotopes are explored starting from excitation spectra and collective wave functions obtained by diagonalization of a core-quasiparticle coupling Hamiltonian based on energy density functionals. As functions of the physical control parameter—the number of nucleons—theoretical low-energy spectra, two-neutron separation energies, charge isotope shifts, spectroscopic quadrupole moments, and E 2 reduced transition matrix elements accurately reproduce available data and exhibit more-pronounced discontinuities at neutron number N =90 compared with the adjacent even-even Sm and Gd isotopes. The enhancement of the first-order quantum phase transition in odd-mass systems can be attributed to a shape polarization effect of the unpaired proton which, at the critical neutron number, starts predominantly coupling to Gd core nuclei that are characterized by larger quadrupole deformation and weaker proton pairing correlations compared with the corresponding Sm isotopes.

  19. Preliminary laboratory testing on the sound absorption of coupled cavity sonic crystal

    NASA Astrophysics Data System (ADS)

    Kristiani, R.; Yahya, I.; Harjana; Suparmi

    2016-11-01

    This paper focuses on the sound absorption performance of coupled cavity sonic crystal. It constructed by a pair of a cylindrical tube with different values in diameters. A laboratory test procedure after ASTM E1050 has been conducted to measure the sound absorption of the sonic crystal elements. The test procedures were implemented to a single coupled scatterer and also to a pair of similar structure. The results showed that using the paired structure bring a better possibility for increase the sound absorption to a wider absorption range. It also bring a practical advantage for setting the local Helmholtz resonant frequency to certain intended frequency.

  20. Ab initio study of Fe(+)-benzyne

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.

    1993-01-01

    The interaction of Fe(+) with benzyne is studied using the self-consistent-field (SCF), complete active space SCF, and modified-coupled-pair functional levels of theory. The most stable structure is planar, where the Fe(+) has inserted into the in-plane pi bond, although the C-C bond distance suggests that some in-plane pi bonding remains. This system is compared with Sc(+) bonding to benzyne and other ligands.

  1. Chemisorption of hydrogen atoms and hydroxyl groups on stretched graphene: A coupled QM/QM study

    NASA Astrophysics Data System (ADS)

    Katin, Konstantin P.; Prudkovskiy, Vladimir S.; Maslov, Mikhail M.

    2017-09-01

    Using the density functional theory coupled with the nonorthogonal tight-binding model, we analyze the chemisorption of hydrogen atoms and hydroxyl groups on the unstrained and stretched graphene sheets. Drawback of finite cluster model of graphene for the chemisorption energy calculation in comparison with the QM/QM approach applied is discussed. It is shown that the chemisorption energy for the hydroxyl group is sufficiently lower than for hydrogen at stretching up to 7.5%. The simultaneous paired chemisorption of hydrogen and hydroxyl groups on the same hexagon has also been examined. Adsorption of two radicals in ortho and para positions is found to be more energetically favorable than those in meta position at any stretching considered. In addition the energy difference between adsorbent pairs in ortho and para positions decreases as the stretching rises. It could be concluded that the graphene stretching leads to the loss of preferred mutual arrangement of two radicals on its surface.

  2. CH stretching overtone spectra of trimethyl amine and dimethyl sulfide

    NASA Astrophysics Data System (ADS)

    Billinghurst, Brant E.; Gough, Kathleen M.; Low, Geoffrey R.; Kjaergaard, Henrik G.

    2004-01-01

    Trimethyl amine (TMA) exhibits the largest known difference in CH bond lengths within a methyl group, due to what is known as the lone pair trans effect. Dimethyl sulfide also exhibits this effect, but to a far lesser extent, making it ideal for comparison to TMA. In this paper, the first through fourth overtone spectra of N(CH3)3, N(CD3)3, N(CD2H)(CD3)2, N(CH3)(CD3)2, N(CD3)(CH3)2 and S(CH3)2 are reported and all major bands are assigned. The intensities of the observed bands are compared to intensities predicted by the harmonically coupled anharmonic oscillator local mode model. Good correlation is found between the experimental intensities and those predicted with the local mode model and HF/6-311++G(2d,2p) calculated dipole moment functions. An increase in the ability to resolve peaks as methyl groups are deuterated suggests that the lone pair mediates increased coupling between methyl groups.

  3. Analysis of trafficking, stability and function of human connexin 26 gap junction channels with deafness-causing mutations in the fourth transmembrane helix.

    PubMed

    Ambrosi, Cinzia; Walker, Amy E; Depriest, Adam D; Cone, Angela C; Lu, Connie; Badger, John; Skerrett, I Martha; Sosinsky, Gina E

    2013-01-01

    Human Connexin26 gene mutations cause hearing loss. These hereditary mutations are the leading cause of childhood deafness worldwide. Mutations in gap junction proteins (connexins) can impair intercellular communication by eliminating protein synthesis, mis-trafficking, or inducing channels that fail to dock or have aberrant function. We previously identified a new class of mutants that form non-functional gap junction channels and hemichannels (connexons) by disrupting packing and inter-helix interactions. Here we analyzed fourteen point mutations in the fourth transmembrane helix of connexin26 (Cx26) that cause non-syndromic hearing loss. Eight mutations caused mis-trafficking (K188R, F191L, V198M, S199F, G200R, I203K, L205P, T208P). Of the remaining six that formed gap junctions in mammalian cells, M195T and A197S formed stable hemichannels after isolation with a baculovirus/Sf9 protein purification system, while C202F, I203T, L205V and N206S formed hemichannels with varying degrees of instability. The function of all six gap junction-forming mutants was further assessed through measurement of dye coupling in mammalian cells and junctional conductance in paired Xenopus oocytes. Dye coupling between cell pairs was reduced by varying degrees for all six mutants. In homotypic oocyte pairings, only A197S induced measurable conductance. In heterotypic pairings with wild-type Cx26, five of the six mutants formed functional gap junction channels, albeit with reduced efficiency. None of the mutants displayed significant alterations in sensitivity to transjunctional voltage or induced conductive hemichannels in single oocytes. Intra-hemichannel interactions between mutant and wild-type proteins were assessed in rescue experiments using baculovirus expression in Sf9 insect cells. Of the four unstable mutations (C202F, I203T, L205V, N206S) only C202F and N206S formed stable hemichannels when co-expressed with wild-type Cx26. Stable M195T hemichannels displayed an increased tendency to aggregate. Thus, mutations in TM4 cause a range of phenotypes of dysfunctional gap junction channels that are discussed within the context of the X-ray crystallographic structure.

  4. ac Josephson effect and resonant Cooper pair tunneling emission of a single Cooper pair transistor.

    PubMed

    Billangeon, P-M; Pierre, F; Bouchiat, H; Deblock, R

    2007-05-25

    We measure the high-frequency emission of a single Cooper pair transistor (SCPT) in the regime where transport is only due to tunneling of Cooper pairs. This is achieved by coupling on chip the SCPT to a superconductor-insulator-superconductor junction and by measuring the photon assisted tunneling current of quasiparticles across the junction. This technique allows a direct detection of the ac Josephson effect of the SCPT and provides evidence of Landau-Zener transitions for proper gate voltage. The emission in the regime of resonant Cooper pair tunneling is also investigated. It is interpreted in terms of transitions between charge states coupled by the Josephson effect.

  5. Quantum entanglement and quantum information in biological systems (DNA)

    NASA Astrophysics Data System (ADS)

    Hubač, Ivan; Švec, Miloslav; Wilson, Stephen

    2017-12-01

    Recent studies of DNA show that the hydrogen bonds between given base pairs can be treated as diabatic systems with spin-orbit coupling. For solid state systems strong diabaticity and spin-orbit coupling the possibility of forming Majorana fermions has been discussed. We analyze the hydrogen bonds in the base pairs in DNA from this perspective. Our analysis is based on a quasiparticle supersymmetric transformation which couples electronic and vibrational motion and includes normal coordinates and the corresponding momenta. We define qubits formed by Majorana fermions in the hydrogen bonds and also discuss the entangled states in base pairs. Quantum information and quantum entropy are introduced. In addition to the well-known classical information connected with the DNA base pairs, we also consider quantum information and show that the classical and quantum information are closely connected.

  6. Chemical Constraints Governing the Origin of Metabolism: The Thermodynamic Landscape of Carbon Group Transformations

    NASA Technical Reports Server (NTRS)

    Weber, Arthur L.; Fonda, Mark (Technical Monitor)

    2001-01-01

    The thermodynamics of organic chemistry under mild aqueous conditions was examined in order to begin to understand its influence on the structure and operation of metabolism and its antecedents. Free energies were estimated for four types reactions of biochemical importance carbon-carbon bond cleavage and synthesis, hydrogen transfer between carbon groups, dehydration of alcohol groups, and aldo-keto isomerization. The energies were calculated for mainly aliphatic groups composed of carbon, hydrogen, and oxygen. The energy values showed that (1) when carbon-carbon bond cleavage involves two different types of functional groups, transfer of the shared electron-pair to the more reduced carbon group is energetically favored over transfer to the more oxidized carbon group, and (2) the energy of carbon-carbon bond transformation is strongly dependent on the type of functional group that donates the shared electron-pair during cleavage, and the group that accepts the shared electron-pair during synthesis, and (3) the energetics of C-C bond transformation is determined primarily by the half-reaction energies of the couples: carbonyl/carboxylic acid, carboxylic acid/carbon dioxide, alcohol/carbonyl, and hydrocarbon/alcohol. The energy of hydrogen-transfer between carbon groups was found to depend on the functional group class of both the hydrogen-donor and hydrogen-acceptor. From these and other observations we concluded that the chemistry of the origin of metabolism (and to a lesser degree modem metabolism) is strongly constrained by the (1) limited disproportionation energy of organic substrates that can be dissipated in a few irreversible reactions, (2) the energy-dominance of few half-reaction couples in carbon-carbon bond transformation that establishes whether a chemical reaction is energetically irreversible, reversible or unfeasible, and (3) the dependence of the transformation-energy on the oxidation state of carbon groups (functional group type) which is contingent on prior reactions in the synthetic pathway.

  7. Magnetic exchange in {Gd(III)-radical} complexes: method assessment, mechanism of coupling and magneto-structural correlations.

    PubMed

    Gupta, Tulika; Rajeshkumar, Thayalan; Rajaraman, Gopalan

    2014-07-28

    Density functional studies have been performed on ten different {Gd(III)-radical} complexes exhibiting both ferro and antiferromagnetic exchange interaction with an aim to assess a suitable exchange-correlation functional within DFT formalism. This study has also been extended to probe the mechanism of magnetic coupling and to develop suitable magneto-structural correlations for this pair. Our method assessments reveal the following order of increasing accuracy for the evaluation of J values compared to experimental coupling constants: B(40HF)LYP < BHandHLYP < TPSSH < PW91 < PBE < BP86 < OLYP < BLYP < PBE0 < X3LYP < B3LYP < B2PLYP. Grimme's double-hybrid functional is found to be superior compared to other functionals tested and this is followed very closely by the conventional hybrid B3LYP functional. At the basis set front, our calculations reveal that the incorporation of relativistic effect is important in these calculations and the relativistically corrected effective core potential (ECP) basis set is found to yield better Js compared to other methods. The supposedly empty 5d/6s/6p orbitals of Gd(III) are found to play an important role in the mechanism of magnetic coupling and different contributions to the exchange terms are probed using Molecular Orbital (MO) and Natural Bond Orbital (NBO) analysis. Magneto-structural correlations for Gd-O distances, Gd-O-N angles and Gd-O-N-C dihedral angles are developed where the bond angles as well as dihedral angle parameters are found to dictate the sign and strength of the magnetic coupling in this series.

  8. Search for heavy resonances decaying to tau lepton pairs in proton-proton collisions at $$ \\sqrt{s}=13$$ TeV

    DOE PAGES

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; ...

    2017-02-09

    A search for heavy resonances that decay to tau lepton pairs is performed using proton-proton collisions at √s = 13 TeV. The data were collected with the CMS detector at the CERN LHC and correspond to an integrated luminosity of 2.2 inverse femtobarns. Our observations are in agreement with standard model predictions. An upper limit at 95% confidence level on the product of the production cross section and branching fraction into tau lepton pairs is calculated as a function of the resonance mass. Furthermore, for the sequential standard model, the presence of Z' bosons decaying into tau lepton pairs ismore » excluded for Z' masses below 2.1 TeV, extending previous limits for this final state. Finally, for the topcolor-assisted technicolor model, which predicts Z' bosons that preferentially couple to third-generation fermions, Z' masses below 1.7 TeV are excluded, representing the most stringent limit to date.« less

  9. AWG Filter for Wavelength Interrogator

    NASA Technical Reports Server (NTRS)

    Black, Richard J. (Inventor); Costa, Joannes M. (Inventor); Moslehi, Behzad (Inventor); Sotoudeh, Vahid (Inventor); Faridian, Fereydoun (Inventor)

    2015-01-01

    A wavelength interrogator is coupled to a circulator which couples optical energy from a broadband source to an optical fiber having a plurality of sensors, each sensor reflecting optical energy at a unique wavelength and directing the reflected optical energy to an AWG. The AWG has a detector coupled to each output, and the reflected optical energy from each grating is coupled to the skirt edge response of the AWG such that the adjacent channel responses form a complementary pair response. The complementary pair response is used to convert an AWG skirt response to a wavelength.

  10. Imaginary parts of coupled electron and phonon propagators

    NASA Astrophysics Data System (ADS)

    Schwartzman, K.; Lawrence, W. E.

    1988-01-01

    Quasiparticle and phonon damping rates due to the electron-phonon and Coulomb interactions are obtained directly from the self-energy formalism of strong-coupling theory. This accounts for all processes involving phonon or quasiparticle decay into a single particle-hole pair, or quasiparticle decay by emission or absorption of a single real phonon. The two quasiparticle decay modes are treated on a common footing, without ad hoc separation, by accounting fully for the dynamics of the phonon propagator and the Coulomb vertex-the latter by expansion of the four-point Coulomb vertex function. The results are shown to be expressible in terms of only the physical (i.e., fully renormalized) energies and coupling constants, and are written in terms of spectral functions such as α2F(ω) and its generalizations. Expansion of these in powers of a phonon linewidth parameter distinguishes (in lowest orders) between quasiparticle decay modes involving real and virtual phonons. However, the simplest prescription for calculating decay rates involves an effective scattering amplitude in which this distinction is not made.

  11. Josephson coupling between superconducting islands on single- and bi-layer graphene

    NASA Astrophysics Data System (ADS)

    Mancarella, Francesco; Fransson, Jonas; Balatsky, Alexander

    2016-05-01

    We study the Josephson coupling of superconducting (SC) islands through the surface of single-layer graphene (SLG) and bilayer graphene (BLG) in the long-junction regime, as a function of the distance between the grains, temperature, chemical potential and external (transverse) gate-voltage. For SLG, we provide a comparison with existing literature. The proximity effect is analyzed through a Matsubara Green’s function approach. This represents the first step in a discussion of the conditions for the onset of a granular superconductivity within the film, made possible by Josephson currents flowing between superconductors. To ensure phase coherence over the 2D sample, a random spatial distribution can be assumed for the SC islands on the SLG sheet (or intercalating the BLG sheets). The tunable gate-voltage-induced band gap of BLG affects the asymptotic decay of the Josephson coupling-distance characteristic for each pair of SC islands in the sample, which results in a qualitatively strong field dependence of the relation between Berezinskii-Kosterlitz-Thouless transition critical temperature and gate voltage.

  12. How to induce multiple delays in coupled chaotic oscillators?

    NASA Astrophysics Data System (ADS)

    Bhowmick, Sourav K.; Ghosh, Dibakar; Roy, Prodyot K.; Kurths, Jürgen; Dana, Syamal K.

    2013-12-01

    Lag synchronization is a basic phenomenon in mismatched coupled systems, delay coupled systems, and time-delayed systems. It is characterized by a lag configuration that identifies a unique time shift between all pairs of similar state variables of the coupled systems. In this report, an attempt is made how to induce multiple lag configurations in coupled systems when different pairs of state variables attain different time shift. A design of coupling is presented to realize this multiple lag synchronization. Numerical illustration is given using examples of the Rössler system and the slow-fast Hindmarsh-Rose neuron model. The multiple lag scenario is physically realized in an electronic circuit of two Sprott systems.

  13. Pairing States of Spin-3/2 Fermions: Symmetry-Enforced Topological Gap Functions

    NASA Astrophysics Data System (ADS)

    Venderbos, Jörn W. F.; Savary, Lucile; Ruhman, Jonathan; Lee, Patrick A.; Fu, Liang

    2018-01-01

    We study the topological properties of superconductors with paired j =3/2 quasiparticles. Higher spin Fermi surfaces can arise, for instance, in strongly spin-orbit coupled band-inverted semimetals. Examples include the Bi-based half-Heusler materials, which have recently been established as low-temperature and low-carrier density superconductors. Motivated by this experimental observation, we obtain a comprehensive symmetry-based classification of topological pairing states in systems with higher angular momentum Cooper pairing. Our study consists of two main parts. First, we develop the phenomenological theory of multicomponent (i.e., higher angular momentum) pairing by classifying the stationary points of the free energy within a Ginzburg-Landau framework. Based on the symmetry classification of stationary pairing states, we then derive the symmetry-imposed constraints on their gap structures. We find that, depending on the symmetry quantum numbers of the Cooper pairs, different types of topological pairing states can occur: fully gapped topological superconductors in class DIII, Dirac superconductors, and superconductors hosting Majorana fermions. Notably, we find a series of nematic fully gapped topological superconductors, as well as double- and triple-Dirac superconductors, with quadratic and cubic dispersion, respectively. Our approach, applied here to the case of j =3/2 Cooper pairing, is rooted in the symmetry properties of pairing states, and can therefore also be applied to other systems with higher angular momentum and high-spin pairing. We conclude by relating our results to experimentally accessible signatures in thermodynamic and dynamic probes.

  14. The Influence of Head Motion on Intrinsic Functional Connectivity MRI

    PubMed Central

    Van Dijk, Koene R.A.; Sabuncu, Mert R.; Buckner, Randy L.

    2011-01-01

    Functional connectivity MRI (fcMRI) has been widely applied to explore group and individual differences. A confounding factor is head motion. Children move more than adults, older adults more than younger adults, and patients more than controls. Head motion varies considerably among individuals within the same population. Here we explored the influence of head motion on fcMRI estimates. Mean head displacement, maximum head displacement, the number of micro movements (> 0.1 mm), and head rotation were estimated in 1000 healthy, young adult subjects each scanned for two resting-state runs on matched 3T scanners. The majority of fcMRI variation across subjects was not linked to estimated head motion. However, head motion had significant, systematic effects on fcMRI network measures. Head motion was associated with decreased functional coupling in the default and frontoparietal control networks – two networks characterized by coupling among distributed regions of association cortex. Other network measures increased with motion including estimates of local functional coupling and coupling between left and right motor regions – a region pair sometimes used as a control in studies to establish specificity. Comparisons between groups of individuals with subtly different levels of head motion yielded difference maps that could be mistaken for neuronal effects in other contexts. These effects are important to consider when interpreting variation between groups and across individuals. PMID:21810475

  15. Synthesis and triplex forming properties of pyrimidine derivative containing extended functionality.

    PubMed

    Gianolio, D A; McLaughlin, L W

    1999-08-01

    Two pyrimidine nucleosides have been synthesized containing extended hydrogen bonding functionality. In one case the side chain is based upon semicarbazide and in the second monoacetylated carbohydrazide was employed. DNA sequences could be prepared using both analogue nucleosides in a reverse coupling protocol, and provided that the normal capping step was eliminated and that the iodine-based oxidizing solution was replaced with one based upon 10-camphorsulfonyl oxaziridine. Both derivatives exhibited moderate effects in targeting selectively C-G base pairs embedded within a polypurine target sequence.

  16. Innexin-3 forms connexin-like intercellular channels.

    PubMed

    Landesman, Y; White, T W; Starich, T A; Shaw, J E; Goodenough, D A; Paul, D L

    1999-07-01

    Innexins comprise a large family of genes that are believed to encode invertebrate gap junction channel-forming proteins. However, only two Drosophila innexins have been directly tested for the ability to form intercellular channels and only one of those was active. Here we tested the ability of Caenorhabditis elegans family members INX-3 and EAT-5 to form intercellular channels between paired Xenopus oocytes. We show that expression of INX-3 but not EAT-5, induces electrical coupling between the oocyte pairs. In addition, analysis of INX-3 voltage and pH gating reveals a striking degree of conservation in the functional properties of connexin and innnexin channels. These data strongly support the idea that innexin genes encode intercellular channels.

  17. Biexciton relaxation associated with dissociation into a surface polariton pair in semiconductor films

    NASA Astrophysics Data System (ADS)

    Mitsumori, Yasuyoshi; Matsuura, Shimpei; Uchiyama, Shoichi; Saito, Kentarao; Edamatsu, Keiichi; Nakayama, Masaaki; Ajiki, Hiroshi

    2018-04-01

    We study the biexciton relaxation process in CuCl films ranging from 6 to 200 nm. The relaxation time is measured as the dephasing time and the lifetime. We observe a unique thickness dependence of the biexciton relaxation time and also obtain an ultrafast relaxation time with a timescale as short as 100 fs, while the exciton lifetime monotonically decreases with increasing thickness. By analyzing the exciton-photon coupling energy for a surface polariton, we theoretically calculate the biexciton relaxation time as a function of the thickness. The calculated dependence qualitatively reproduces the observed relaxation time, indicating that the biexciton dissociation into a surface polariton pair is one of the major biexciton relaxation processes.

  18. Two-dimensional fourier transform spectrometer

    DOEpatents

    DeFlores, Lauren; Tokmakoff, Andrei

    2016-10-25

    The present invention relates to a system and methods for acquiring two-dimensional Fourier transform (2D FT) spectra. Overlap of a collinear pulse pair and probe induce a molecular response which is collected by spectral dispersion of the signal modulated probe beam. Simultaneous collection of the molecular response, pulse timing and characteristics permit real time phasing and rapid acquisition of spectra. Full spectra are acquired as a function of pulse pair timings and numerically transformed to achieve the full frequency-frequency spectrum. This method demonstrates the ability to acquire information on molecular dynamics, couplings and structure in a simple apparatus. Multi-dimensional methods can be used for diagnostic and analytical measurements in the biological, biomedical, and chemical fields.

  19. Two-dimensional fourier transform spectrometer

    DOEpatents

    DeFlores, Lauren; Tokmakoff, Andrei

    2013-09-03

    The present invention relates to a system and methods for acquiring two-dimensional Fourier transform (2D FT) spectra. Overlap of a collinear pulse pair and probe induce a molecular response which is collected by spectral dispersion of the signal modulated probe beam. Simultaneous collection of the molecular response, pulse timing and characteristics permit real time phasing and rapid acquisition of spectra. Full spectra are acquired as a function of pulse pair timings and numerically transformed to achieve the full frequency-frequency spectrum. This method demonstrates the ability to acquire information on molecular dynamics, couplings and structure in a simple apparatus. Multi-dimensional methods can be used for diagnostic and analytical measurements in the biological, biomedical, and chemical fields.

  20. All-optical diffractive/transmissive switch based on coupled cycloidal diffractive waveplates.

    PubMed

    Serak, Svetlana V; Hakobyan, Rafael S; Nersisyan, Sarik R; Tabiryan, Nelson V; White, Timothy J; Bunning, Timothy J; Steeves, Diane M; Kimball, Brian R

    2012-02-27

    Pairs of cycloidal diffractive waveplates can be used to doubly diffract or collinearly propagate laser radiation of the appropriate wavelength. The use of a dynamic phase retarder placed in between the pair can be utilized to switch between the two optical states. We present results from the implementation of an azo-based retarder whose optical properties can be modulated using light itself. We show fast and efficient switching between the two states for both CW and single nanosecond laser pulses of green radiation. Contrasts greater than 100:1 were achieved. The temporal response as a function of light intensity is presented and the optical switching is shown to be polarization independent.

  1. Electrostatic screening in classical Coulomb fluids: exponential or power-law decay or both? An investigation into the effect of dispersion interactions

    NASA Astrophysics Data System (ADS)

    Kjellander, Roland

    2006-04-01

    It is shown that the nature of the non-electrostatic part of the pair interaction potential in classical Coulomb fluids can have a profound influence on the screening behaviour. Two cases are compared: (i) when the non-electrostatic part equals an arbitrary finite-ranged interaction and (ii) when a dispersion r-6 interaction potential is included. A formal analysis is done in exact statistical mechanics, including an investigation of the bridge function. It is found that the Coulombic r-1 and the dispersion r-6 potentials are coupled in a very intricate manner as regards the screening behaviour. The classical one-component plasma (OCP) is a particularly clear example due to its simplicity and is investigated in detail. When the dispersion r-6 potential is turned on, the screened electrostatic potential from a particle goes from a monotonic exponential decay, exp(-κr)/r, to a power-law decay, r-8, for large r. The pair distribution function acquire, at the same time, an r-10 decay for large r instead of the exponential one. There still remains exponentially decaying contributions to both functions, but these contributions turn oscillatory when the r-6 interaction is switched on. When the Coulomb interaction is turned off but the dispersion r-6 pair potential is kept, the decay of the pair distribution function for large r goes over from the r-10 to an r-6 behaviour, which is the normal one for fluids of electroneutral particles with dispersion interactions. Differences and similarities compared to binary electrolytes are pointed out.

  2. Emergence of a new pair-coherent phase in many-body quenches of repulsive bosons

    NASA Astrophysics Data System (ADS)

    Fischer, Uwe R.; Lee, Kang-Soo; Xiong, Bo

    2011-07-01

    We investigate the dynamical mode population statistics and associated first- and second-order coherence of an interacting bosonic two-mode model when the pair-exchange coupling is quenched from negative to positive values. It is shown that for moderately rapid second-order transitions, a new pair-coherent phase emerges on the positive coupling side in an excited state, which is not fragmented as the ground-state single-particle density matrix would prescribe it to be.

  3. Dynamic Properties of Electrotonic Coupling between Cells of Early Xenopus Embryos

    PubMed Central

    DiCaprio, R. A.; French, A. S.; Sanders, E. J.

    1974-01-01

    Frequency response functions were measured between the cells of Xenopus laevis embryos during the first two cleavage stages. Linear systems theory was then used to produce electronic models which account for the electrical behavior of the systems. Coupling between the cells may be explained by models which have simple resistive elements joining each cell to its neighbors. The vitelline, or fertilization, membrane which surrounds the embryos has no detectable resistance to the passage of electric current. The electrical properties of the four-cell embryo can only be explained by the existence of individual junctions linking each pair of cells. This arrangement suggests that electrotonic coupling is important in the development of the embryos, at least until the four-cell stage. ImagesFIGURE 5FIGURE 14FIGURE 15 PMID:19431351

  4. Weakly and strongly coupled Belousov-Zhabotinsky patterns.

    PubMed

    Weiss, Stephan; Deegan, Robert D

    2017-02-01

    We investigate experimentally and numerically the synchronization of two-dimensional spiral wave patterns in the Belousov-Zhabotinsky reaction due to point-to-point coupling of two separate domains. Different synchronization modalities appear depending on the coupling strength and the initial patterns in each domain. The behavior as a function of the coupling strength falls into two qualitatively different regimes. The weakly coupled regime is characterized by inter-domain interactions that distorted but do not break wave fronts. Under weak coupling, spiral cores are pushed around by wave fronts in the other domain, resulting in an effective interaction between cores in opposite domains. In the case where each domain initially contains a single spiral, the cores form a bound pair and orbit each other at quantized distances. When the starting patterns consist of multiple randomly positioned spiral cores, the number of cores decreases with time until all that remains are a few cores that are synchronized with a partner in the other domain. The strongly coupled regime is characterized by interdomain interactions that break wave fronts. As a result, the wave patterns in both domains become identical.

  5. Weakly and strongly coupled Belousov-Zhabotinsky patterns

    NASA Astrophysics Data System (ADS)

    Weiss, Stephan; Deegan, Robert D.

    2017-02-01

    We investigate experimentally and numerically the synchronization of two-dimensional spiral wave patterns in the Belousov-Zhabotinsky reaction due to point-to-point coupling of two separate domains. Different synchronization modalities appear depending on the coupling strength and the initial patterns in each domain. The behavior as a function of the coupling strength falls into two qualitatively different regimes. The weakly coupled regime is characterized by inter-domain interactions that distorted but do not break wave fronts. Under weak coupling, spiral cores are pushed around by wave fronts in the other domain, resulting in an effective interaction between cores in opposite domains. In the case where each domain initially contains a single spiral, the cores form a bound pair and orbit each other at quantized distances. When the starting patterns consist of multiple randomly positioned spiral cores, the number of cores decreases with time until all that remains are a few cores that are synchronized with a partner in the other domain. The strongly coupled regime is characterized by interdomain interactions that break wave fronts. As a result, the wave patterns in both domains become identical.

  6. Artificial Synaptic Devices Based on Natural Chicken Albumen Coupled Electric-Double-Layer Transistors

    NASA Astrophysics Data System (ADS)

    Wu, Guodong; Feng, Ping; Wan, Xiang; Zhu, Liqiang; Shi, Yi; Wan, Qing

    2016-03-01

    Recent progress in using biomaterials to fabricate functional electronics has got growing attention for the new generation of environmentally friendly and biocompatible electronic devices. As a kind of biological material with rich source, proteins are essential natural component of all organisms. At the same time, artificial synaptic devices are of great significance for neuromorphic systems because they can emulate the signal process and memory behaviors of biological synapses. In this report, natural chicken albumen with high proton conductivity was used as the coupling electrolyte film for organic/inorganic hybrid synaptic devices fabrication. Some important synaptic functions including paired-pulse facilitation, dynamic filtering, short-term to long-term memory transition and spatial summation and shunting inhibition were successfully mimicked. Our results are very interesting for biological friendly artificial neuron networks and neuromorphic systems.

  7. Implicit multisensory associations influence voice recognition.

    PubMed

    von Kriegstein, Katharina; Giraud, Anne-Lise

    2006-10-01

    Natural objects provide partially redundant information to the brain through different sensory modalities. For example, voices and faces both give information about the speech content, age, and gender of a person. Thanks to this redundancy, multimodal recognition is fast, robust, and automatic. In unimodal perception, however, only part of the information about an object is available. Here, we addressed whether, even under conditions of unimodal sensory input, crossmodal neural circuits that have been shaped by previous associative learning become activated and underpin a performance benefit. We measured brain activity with functional magnetic resonance imaging before, while, and after participants learned to associate either sensory redundant stimuli, i.e. voices and faces, or arbitrary multimodal combinations, i.e. voices and written names, ring tones, and cell phones or brand names of these cell phones. After learning, participants were better at recognizing unimodal auditory voices that had been paired with faces than those paired with written names, and association of voices with faces resulted in an increased functional coupling between voice and face areas. No such effects were observed for ring tones that had been paired with cell phones or names. These findings demonstrate that brief exposure to ecologically valid and sensory redundant stimulus pairs, such as voices and faces, induces specific multisensory associations. Consistent with predictive coding theories, associative representations become thereafter available for unimodal perception and facilitate object recognition. These data suggest that for natural objects effective predictive signals can be generated across sensory systems and proceed by optimization of functional connectivity between specialized cortical sensory modules.

  8. Spin-Triplet Pairing Induced by Spin-Singlet Interactions in Noncentrosymmetric Superconductors

    NASA Astrophysics Data System (ADS)

    Matsuzaki, Tomoaki; Shimahara, Hiroshi

    2017-02-01

    In noncentrosymmetric superconductors, we examine the effect of the difference between the intraband and interband interactions, which becomes more important when the band splitting increases. We define the difference ΔVμ between their coupling constants, i.e., that between the intraband and interband hopping energies of intraband Cooper pairs. Here, the subscript μ of ΔVμ indicates that the interactions scatter the spin-singlet and spin-triplet pairs when μ = 0 and μ = 1,2,3, respectively. It is shown that the strong antisymmetric spin-orbit interaction reverses the target spin parity of the interaction: it converts the spin-singlet and spin-triplet interactions represented by ΔV0 and ΔVμ>0 into effective spin-triplet and spin-singlet pairing interactions, respectively. Hence, for example, triplet pairing can be induced solely by the singlet interaction ΔV0. We name the pairing symmetry of the system after that of the intraband Cooper pair wave function, but with an odd-parity phase factor excluded. The pairing symmetry must then be even, even for the triplet component, and the following results are obtained. When ΔVμ is small, the spin-triplet p-wave interactions induce spin-triplet s-wave and spin-triplet d-wave pairings in the regions where the repulsive singlet s-wave interaction is weak and strong, respectively. When ΔV0 is large, a repulsive interband spin-singlet interaction can stabilize spin-triplet pairing. When the Rashba interaction is adopted for the spin-orbit interaction, the spin-triplet pairing interactions mediated by transverse magnetic fluctuations do not contribute to triplet pairing.

  9. Metastable dynamical patterns and their stabilization in arrays of bidirectionally coupled sigmoidal neurons

    NASA Astrophysics Data System (ADS)

    Horikawa, Yo

    2013-12-01

    Transient patterns in a bistable ring of bidirectionally coupled sigmoidal neurons were studied. When the system had a pair of spatially uniform steady solutions, the instability of unstable spatially nonuniform steady solutions decreased exponentially with the number of neurons because of the symmetry of the system. As a result, transient spatially nonuniform patterns showed dynamical metastability: Their duration increased exponentially with the number of neurons and the duration of randomly generated patterns obeyed a power-law distribution. However, these metastable dynamical patterns were easily stabilized in the presence of small variations in coupling strength. Metastable rotating waves and their pinning in the presence of asymmetry in the direction of coupling and the disappearance of metastable dynamical patterns due to asymmetry in the output function of a neuron were also examined. Further, in a two-dimensional array of neurons with nearest-neighbor coupling, intrinsically one-dimensional patterns were dominant in transients, and self-excitation in these neurons affected the metastable dynamical patterns.

  10. Coupled uncertainty provided by a multifractal random walker

    NASA Astrophysics Data System (ADS)

    Koohi Lai, Z.; Vasheghani Farahani, S.; Movahed, S. M. S.; Jafari, G. R.

    2015-10-01

    The aim here is to study the concept of pairing multifractality between time series possessing non-Gaussian distributions. The increasing number of rare events creates ;criticality;. We show how the pairing between two series is affected by rare events, which we call ;coupled criticality;. A method is proposed for studying the coupled criticality born out of the interaction between two series, using the bivariate multifractal random walk (BiMRW). This method allows studying dependence of the coupled criticality on the criticality of each individual system. This approach is applied to data sets of gold and oil markets, and inflation and unemployment.

  11. Dynamic functional-structural coupling within acute functional state change phases: Evidence from a depression recognition study.

    PubMed

    Bi, Kun; Hua, Lingling; Wei, Maobin; Qin, Jiaolong; Lu, Qing; Yao, Zhijian

    2016-02-01

    Dynamic functional-structural connectivity (FC-SC) coupling might reflect the flexibility by which SC relates to functional connectivity (FC). However, during the dynamic acute state change phases of FC, the relationship between FC and SC may be distinctive and embody the abnormality inherent in depression. This study investigated the depression-related inter-network FC-SC coupling within particular dynamic acute state change phases of FC. Magnetoencephalography (MEG) and diffusion tensor imaging (DTI) data were collected from 26 depressive patients (13 women) and 26 age-matched controls (13 women). We constructed functional brain networks based on MEG data and structural networks from DTI data. The dynamic connectivity regression algorithm was used to identify the state change points of a time series of inter-network FC. The time period of FC that contained change points were partitioned into types of dynamic phases (acute rising phase, acute falling phase,acute rising and falling phase and abrupt FC variation phase) to explore the inter-network FC-SC coupling. The selected FC-SC couplings were then fed into the support vector machine (SVM) for depression recognition. The best discrimination accuracy was 82.7% (P=0.0069) with FC-SC couplings, particularly in the acute rising phase of FC. Within the FC phases of interest, the significant discriminative network pair was related to the salience network vs ventral attention network (SN-VAN) (P=0.0126) during the early rising phase (70-170ms). This study suffers from a small sample size, and the individual acute length of the state change phases was not considered. The increased values of significant discriminative vectors of FC-SC coupling in depression suggested that the capacity to process negative emotion might be more directly related to the SC abnormally and be indicative of more stringent and less dynamic brain function in SN-VAN, especially in the acute rising phase of FC. We demonstrated that depressive brain dysfunctions could be better characterized by reduced FC-SC coupling flexibility in this particular phase. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Theoretical study of the hyperfine parameters of OH

    NASA Technical Reports Server (NTRS)

    Chong, Delano P.; Langhoff, Stephen R.; Bauschlicher, Charles W., Jr.

    1991-01-01

    In the present study of the hyperfine parameters of O-17H as a function of the one- and n-particle spaces, all of the parameters except oxygen's spin density, b sub F(O), are sufficiently easily tractable to allow concentration on the computational requirements for accurate determination of b sub F(O). Full configuration-interaction (FCI) calculations in six Gaussian basis sets yield unambiguous results for (1) the effect of uncontracting the O s and p basis sets; (2) that of adding diffuse s and p functions; and (3) that of adding polarization functions to O. The size-extensive modified coupled-pair functional method yields b sub F values which are in fair agreement with FCI results.

  13. Theoretical study of the electric dipole moment function of the ClO molecule

    NASA Technical Reports Server (NTRS)

    Pettersson, L. G. M.; Langhoff, S. R.; Chong, D. P.

    1986-01-01

    The potential energy function and electric dipole moment function (EDMF) are computed for ClO X 2Pi using several different techniques to include electron correlation. The EDMF is used to compute Einstein coefficients, vibrational lifetimes, and dipole moments in higher vibrational levels. The band strength of the 1-0 fundamental transition is computed to be 12 + or - 2 per sq cm atm determined from infrared heterodyne spectroscopy. The theoretical methods used include SCF, CASSCF, multireference singles plus doubles configuration interaction (MRCI) and contracted CI, coupled pair functional (CPF), and a modified version of the CPF method. The results obtained using the different methods are critically compared.

  14. The precarious couple effect: verbally inhibited men + critical, disinhibited women = bad chemistry.

    PubMed

    Swann, William B; Rentfrow, Peter J; Gosling, Samuel D

    2003-12-01

    When critical, verbally disinhibited women are paired with verbally inhibited men, relationship quality suffers, rendering the relationship precarious. This effect theoretically emerges when (a). verbally disinhibited women pair with relatively inhibited men (man-more-inhibited couples) and (b). the disinhibition of women in man-more-inhibited couples amplifies women's criticalness and alienates men. Three studies (Ns=437, 300, and 564) provided evidence that relationship quality suffered in man-more-inhibited couples; a 4th study (N=168) showed that the criticalness of women in man-more-inhibited couples did indeed undermine relationship quality. Implications for understanding the impact of gender expectations on relationships and for integrating behavioral and personological approaches to close relationships are discussed.

  15. Spin Josephson effect in topological superconductor-ferromagnet junction

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

    Ren, C. D.; Wang, J., E-mail: jwang@seu.edu.cn

    2014-03-21

    The composite topological superconductor (TS), made of one-dimensional spin-orbit coupled nanowire with proximity-induced s-wave superconductivity, is not a pure p-wave superconductor but still has a suppressed s-wave pairing. We propose to probe the spin texture of the p-wave pairing in this composite TS by examining possible spin supercurrents in an unbiased TS/ferromagnet junction. It is found that both the exchange-coupling induced and spin-flip reflection induced spin currents exist in the setup and survive even in the topological phase. We showed that besides the nontrivial p-wave pairing state accounting for Majorana Fermions, there shall be a trivial p-wave pairing state thatmore » contributes to spin supercurrent. The trivial p-wave pairing state is diagnosed from the mixing effect between the suppressed s-wave pairing and the topologically nontrivial p-wave pairing. The d vector of the TS is proved not to be rigorously perpendicular to the spin projection of p-wave pairings. Our findings are also confirmed by the Kitaev's p-wave model with a nonzero s-wave pairing.« less

  16. Tracking the coherent generation of polaron pairs in conjugated polymers

    NASA Astrophysics Data System (ADS)

    de Sio, Antonietta; Troiani, Filippo; Maiuri, Margherita; Réhault, Julien; Sommer, Ephraim; Lim, James; Huelga, Susana F.; Plenio, Martin B.; Rozzi, Carlo Andrea; Cerullo, Giulio; Molinari, Elisa; Lienau, Christoph

    2016-12-01

    The optical excitation of organic semiconductors not only generates charge-neutral electron-hole pairs (excitons), but also charge-separated polaron pairs with high yield. The microscopic mechanisms underlying this charge separation have been debated for many years. Here we use ultrafast two-dimensional electronic spectroscopy to study the dynamics of polaron pair formation in a prototypical polymer thin film on a sub-20-fs time scale. We observe multi-period peak oscillations persisting for up to about 1 ps as distinct signatures of vibronic quantum coherence at room temperature. The measured two-dimensional spectra show pronounced peak splittings revealing that the elementary optical excitations of this polymer are hybridized exciton-polaron-pairs, strongly coupled to a dominant underdamped vibrational mode. Coherent vibronic coupling induces ultrafast polaron pair formation, accelerates the charge separation dynamics and makes it insensitive to disorder. These findings open up new perspectives for tailoring light-to-current conversion in organic materials.

  17. Pairing induced superconductivity in holography

    NASA Astrophysics Data System (ADS)

    Bagrov, Andrey; Meszena, Balazs; Schalm, Koenraad

    2014-09-01

    We study pairing induced superconductivity in large N strongly coupled systems at finite density using holography. In the weakly coupled dual gravitational theory the mechanism is conventional BCS theory. An IR hard wall cut-off is included to ensure that we can controllably address the dynamics of a single confined Fermi surface. We address in detail the interplay between the scalar order parameter field and fermion pairing. Adding an explicitly dynamical scalar operator with the same quantum numbers as the fermion-pair, the theory experiences a BCS/BEC crossover controlled by the relative scaling dimensions. We find the novel result that this BCS/BEC crossover exposes resonances in the canonical expectation value of the scalar operator. This occurs not only when the scaling dimension is degenerate with the Cooper pair, but also with that of higher derivative paired operators. We speculate that a proper definition of the order parameter which takes mixing with these operators into account stays finite nevertheless.

  18. Rotary electrical contact device and method for providing current to and/or from a rotating member

    DOEpatents

    Koplow, Jeffrey P

    2013-11-19

    Examples of rotary electrical connectors include a first pair and a second pair of opposing sheaves coupled together by intersecting first shaft connecting the first pair of opposing sheaves and a second shaft connecting the second pair of opposing sheaves, and at least partially electrically conductive belt disposed about respective perimeters of the first pair and second pair of opposing sheaves and adapted to remain in contact with at least a portion of the respective perimeters of the sheaves during motion of said sheaves. In example devices, one of the plurality of sheaves may remain stationary during operation of the device while the remaining sheaves rotate and/or orbit around a center axis of the stationary sheave, the device being configured to couple current between a stationary power source and a rotating member through the electrically conductive belt.

  19. Signatures of van der Waals binding: A coupling-constant scaling analysis

    NASA Astrophysics Data System (ADS)

    Jiao, Yang; Schröder, Elsebeth; Hyldgaard, Per

    2018-02-01

    The van der Waals (vdW) density functional (vdW-DF) method [Rep. Prog. Phys. 78, 066501 (2015), 10.1088/0034-4885/78/6/066501] describes dispersion or vdW binding by tracking the effects of an electrodynamic coupling among pairs of electrons and their associated exchange-correlation holes. This is done in a nonlocal-correlation energy term Ecnl, which permits density functional theory calculation in the Kohn-Sham scheme. However, to map the nature of vdW forces in a fully interacting materials system, it is necessary to also account for associated kinetic-correlation energy effects. Here, we present a coupling-constant scaling analysis, which permits us to compute the kinetic-correlation energy Tcnl that is specific to the vdW-DF account of nonlocal correlations. We thus provide a more complete spatially resolved analysis of the electrodynamical-coupling nature of nonlocal-correlation binding, including vdW attraction, in both covalently and noncovalently bonded systems. We find that kinetic-correlation energy effects play a significant role in the account of vdW or dispersion interactions among molecules. Furthermore, our mapping shows that the total nonlocal-correlation binding is concentrated to pockets in the sparse electron distribution located between the material fragments.

  20. Polynomial Similarity Transformation Theory: A smooth interpolation between coupled cluster doubles and projected BCS applied to the reduced BCS Hamiltonian

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

    Degroote, M.; Henderson, T. M.; Zhao, J.

    We present a similarity transformation theory based on a polynomial form of a particle-hole pair excitation operator. In the weakly correlated limit, this polynomial becomes an exponential, leading to coupled cluster doubles. In the opposite strongly correlated limit, the polynomial becomes an extended Bessel expansion and yields the projected BCS wavefunction. In between, we interpolate using a single parameter. The e ective Hamiltonian is non-hermitian and this Polynomial Similarity Transformation Theory follows the philosophy of traditional coupled cluster, left projecting the transformed Hamiltonian onto subspaces of the Hilbert space in which the wave function variance is forced to be zero.more » Similarly, the interpolation parameter is obtained through minimizing the next residual in the projective hierarchy. We rationalize and demonstrate how and why coupled cluster doubles is ill suited to the strongly correlated limit whereas the Bessel expansion remains well behaved. The model provides accurate wave functions with energy errors that in its best variant are smaller than 1% across all interaction stengths. The numerical cost is polynomial in system size and the theory can be straightforwardly applied to any realistic Hamiltonian.« less

  1. Deck the Halls. Animated Displays: Coupled Mechanical Oscillators.

    ERIC Educational Resources Information Center

    Pizzo, Joe, Ed.

    1992-01-01

    Describes a set of displays on the theme of coupled mechanical oscillators. Displays encompass three common demonstrations: (1) a coupled pair of identical pendulums; (2) a multiple-pendulum resonance demonstration; and (3) a Wilberforce coupled oscillator. (MDH)

  2. Integrable pair-transition-coupled nonlinear Schrödinger equations.

    PubMed

    Ling, Liming; Zhao, Li-Chen

    2015-08-01

    We study integrable coupled nonlinear Schrödinger equations with pair particle transition between components. Based on exact solutions of the coupled model with attractive or repulsive interaction, we predict that some new dynamics of nonlinear excitations can exist, such as the striking transition dynamics of breathers, new excitation patterns for rogue waves, topological kink excitations, and other new stable excitation structures. In particular, we find that nonlinear wave solutions of this coupled system can be written as a linear superposition of solutions for the simplest scalar nonlinear Schrödinger equation. Possibilities to observe them are discussed in a cigar-shaped Bose-Einstein condensate with two hyperfine states. The results would enrich our knowledge on nonlinear excitations in many coupled nonlinear systems with transition coupling effects, such as multimode nonlinear fibers, coupled waveguides, and a multicomponent Bose-Einstein condensate system.

  3. Noise-enhanced coupling between two oscillators with long-term plasticity

    NASA Astrophysics Data System (ADS)

    Lücken, Leonhard; Popovych, Oleksandr V.; Tass, Peter A.; Yanchuk, Serhiy

    2016-03-01

    Spike timing-dependent plasticity is a fundamental adaptation mechanism of the nervous system. It induces structural changes of synaptic connectivity by regulation of coupling strengths between individual cells depending on their spiking behavior. As a biophysical process its functioning is constantly subjected to natural fluctuations. We study theoretically the influence of noise on a microscopic level by considering only two coupled neurons. Adopting a phase description for the neurons we derive a two-dimensional system which describes the averaged dynamics of the coupling strengths. We show that a multistability of several coupling configurations is possible, where some configurations are not found in systems without noise. Intriguingly, it is possible that a strong bidirectional coupling, which is not present in the noise-free situation, can be stabilized by the noise. This means that increased noise, which is normally expected to desynchronize the neurons, can be the reason for an antagonistic response of the system, which organizes itself into a state of stronger coupling and counteracts the impact of noise. This mechanism, as well as a high potential for multistability, is also demonstrated numerically for a coupled pair of Hodgkin-Huxley neurons.

  4. Free-space quantum key distribution with a high generation rate potassium titanyl phosphate waveguide photon-pair source

    NASA Astrophysics Data System (ADS)

    Wilson, Jeffrey D.; Chaffee, Dalton W.; Wilson, Nathaniel C.; Lekki, John D.; Tokars, Roger P.; Pouch, John J.; Roberts, Tony D.; Battle, Philip R.; Floyd, Bertram; Lind, Alexander J.; Cavin, John D.; Helmick, Spencer R.

    2016-09-01

    A high generation rate photon-pair source using a dual element periodically-poled potassium titanyl phosphate (PP KTP) waveguide is described. The fully integrated photon-pair source consists of a 1064-nm pump diode laser, fiber-coupled to a dual element waveguide within which a pair of 1064-nm photons are up-converted to a single 532-nm photon in the first stage. In the second stage, the 532-nm photon is down-converted to an entangled photon-pair at 800 nm and 1600 nm which are fiber-coupled at the waveguide output. The photon-pair source features a high pair generation rate, a compact power-efficient package, and continuous wave (CW) or pulsed operation. This is a significant step towards the long term goal of developing sources for high-rate Quantum Key Distribution (QKD) to enable Earth-space secure communications. Characterization and test results are presented. Details and preliminary results of a laboratory free space QKD experiment with the B92 protocol are also presented.

  5. Free-Space Quantum Key Distribution with a High Generation Rate Potassium Titanyl Phosphate Waveguide Photon-Pair Source

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.; Chaffee, Dalton W.; Wilson, Nathaniel C.; Lekki, John D.; Tokars, Roger P.; Pouch, John J.; Roberts, Tony D.; Battle, Philip; Floyd, Bertram M.; Lind, Alexander J.; hide

    2016-01-01

    A high generation rate photon-pair source using a dual element periodically-poled potassium titanyl phosphate (PP KTP) waveguide is described. The fully integrated photon-pair source consists of a 1064-nanometer pump diode laser, fiber-coupled to a dual element waveguide within which a pair of 1064-nanometer photons are up-converted to a single 532-nanometer photon in the first stage. In the second stage, the 532-nanometer photon is down-converted to an entangled photon-pair at 800 nanometer and 1600 nanometer which are fiber-coupled at the waveguide output. The photon-pair source features a high pair generation rate, a compact power-efficient package, and continuous wave (CW) or pulsed operation. This is a significant step towards the long term goal of developing sources for high-rate Quantum Key Distribution (QKD) to enable Earth-space secure communications. Characterization and test results are presented. Details and preliminary results of a laboratory free-space QKD experiment with the B92 protocol are also presented.

  6. Effect of Fibonacci modulation on superconductivity

    NASA Astrophysics Data System (ADS)

    Gupta, Sanjay; Sil, Shreekantha; Bhattacharyya, Bibhas

    2006-02-01

    We have studied finite-sized single band models with short-range pairing interactions between electrons in the presence of diagonal Fibonacci modulation in one dimension. Two models, namely the attractive Hubbard model and the Penson-Kolb model, have been investigated at half-filling at zero temperature by solving the Bogoliubov-de Gennes equations in real space within a mean-field approximation. The competition between 'disorder' and the pairing interaction leads to a suppression of superconductivity (of usual pairs with zero centre-of-mass momenta) in the strong-coupling limit while an enhancement of the pairing correlation is observed in the weak-coupling regime for both models. However, the dissimilarity of the pairing mechanisms in these two models brings about notable differences in the results. The extent to which the bond-ordered wave and the η-paired (of pairs with centre-of-mass momenta = π) phases of the Penson-Kolb model are affected by the disorder has also been studied in the present calculation. Some finite size effects are also identified.

  7. Tunable 0-π transition by interband coupling in iron-based superconductor Josephson junctions

    NASA Astrophysics Data System (ADS)

    Tao, Y. C.; Liu, S. Y.; Bu, N.; Wang, J.; Di, Y. S.

    2016-01-01

    An extended four-component Bogoliubov-de Gennes equation is applied to study the Josephson effect in ballistic limit between either two iron-based superconductors (SCs) or an iron-based SC and a conventional s-wave SC, separated by a normal metal. A 0-π transition as a function of interband coupling strength α is always exhibited, arising from the tuning of mixing between the two trajectories with opposite phases. The novel property can be experimentally used to discriminate the {s}+/- -wave pairing symmetry in the iron-based SCs from the {s}++-wave one in MgB2. The effect of interface transparency on the 0-π transition is also presented. The 0-π transition as a function of α is wholly distinct from that as a function of barrier strength or temperature in recent theories (Linder et al 2009 Phys. Rev. B 80 020503(R)). The possible experimental probe of the phase-shift effect in iron-based SC Josephson junctions is commented on as well.

  8. Optical properties of azobenzene-functionalized self-assembled monolayers: Intermolecular coupling and many-body interactions

    NASA Astrophysics Data System (ADS)

    Cocchi, Caterina; Moldt, Thomas; Gahl, Cornelius; Weinelt, Martin; Draxl, Claudia

    2016-12-01

    In a joint theoretical and experimental work, the optical properties of azobenzene-functionalized self-assembled monolayers (SAMs) are studied at different molecular packing densities. Our results, based on density-functional and many-body perturbation theory, as well as on differential reflectance (DR) spectroscopy, shed light on the microscopic mechanisms ruling photo-absorption in these systems. While the optical excitations are intrinsically excitonic in nature, regardless of the molecular concentration, in densely packed SAMs intermolecular coupling and local-field effects are responsible for a sizable weakening of the exciton binding strength. Through a detailed analysis of the character of the electron-hole pairs, we show that distinct excitations involved in the photo-isomerization at low molecular concentrations are dramatically broadened by intermolecular interactions. Spectral shifts in the calculated DR spectra are in good agreement with the experimental results. Our findings represent an important step forward to rationalize the excited-state properties of these complex materials.

  9. Artificial synapse network on inorganic proton conductor for neuromorphic systems.

    PubMed

    Zhu, Li Qiang; Wan, Chang Jin; Guo, Li Qiang; Shi, Yi; Wan, Qing

    2014-01-01

    The basic units in our brain are neurons, and each neuron has more than 1,000 synapse connections. Synapse is the basic structure for information transfer in an ever-changing manner, and short-term plasticity allows synapses to perform critical computational functions in neural circuits. Therefore, the major challenge for the hardware implementation of neuromorphic computation is to develop artificial synapse network. Here in-plane lateral-coupled oxide-based artificial synapse network coupled by proton neurotransmitters are self-assembled on glass substrates at room-temperature. A strong lateral modulation is observed due to the proton-related electrical-double-layer effect. Short-term plasticity behaviours, including paired-pulse facilitation, dynamic filtering and spatiotemporally correlated signal processing are mimicked. Such laterally coupled oxide-based protonic/electronic hybrid artificial synapse network proposed here is interesting for building future neuromorphic systems.

  10. Semirational rogue waves for the three-coupled fourth-order nonlinear Schrödinger equations in an alpha helical protein

    NASA Astrophysics Data System (ADS)

    Du, Zhong; Tian, Bo; Qu, Qi-Xing; Chai, Han-Peng; Wu, Xiao-Yu

    2017-12-01

    Investigated in this paper are the three-coupled fourth-order nonlinear Schrödinger equations, which describe the dynamics of alpha helical protein with the interspine coupling at the higher order. We show that the representation of the Lax pair with Expressions (42) -(45) in Ref. [25] is not correct, because the three-coupled fourth-order nonlinear Schrödinger equations can not be reproduced by the Lax pair with Expressions (42) -(45) in Ref. [25] through the compatibility condition. Therefore, we recalculate the Lax pair. Based on the recalculated Lax pair, we construct the generalized Darboux transformation, and derive the first- and second-order semirational solutions. Through such solutions, dark-bright-bright soliton, breather-breather-bright soliton, breather soliton and rogue waves are analyzed. It is found that the rogue waves in the three components are mutually proportional. Moreover, three types of the semirational rogue waves consisting of the rogue waves and solitons are presented: (1) consisting of the first-order rogue wave and one soliton; (2) consisting of the first-order rogue wave and two solitons; (3) consisting of the second-order rogue wave and two solitons.

  11. Modulation of chloroplast movement in the green alga Mougeotia by the Ca2+ ionophore A23187 and by calmodulin antagonists.

    PubMed Central

    Serlin, B S; Roux, S J

    1984-01-01

    The Ca2+ ionophore A23187 can induce chloroplast rotation within a single nonirradiated Mougeotia cell. The induced turning was dependent on the position of ionophore application and Ca2+ in the external medium. The role of calmodulin in mediating light-induced chloroplast rotation in the alga Mougeotia was investigated by using the paired calmodulin-antagonist drugs W5-W7 and W12-W13. In each pair, the antagonist with the greater affinity for calmodulin had the greater inhibitor effect on the phytochrome-controlled light response. These results support the hypothesis that calcium functions as a chemical messenger to couple the stimulus of phytochrome photoactivation with physiological responses in plants. Images PMID:11536594

  12. High speed preamplifier circuit, detection electronics, and radiation detection systems therefrom

    DOEpatents

    Riedel, Richard A [Knoxville, TN; Wintenberg, Alan L [Knoxville, TN; Clonts, Lloyd G [Knoxville, TN; Cooper, Ronald G [Oak Ridge, TN

    2010-09-21

    A preamplifier circuit for processing a signal provided by a radiation detector includes a transimpedance amplifier coupled to receive a current signal from a detector and generate a voltage signal at its output. A second amplification stage has an input coupled to an output of the transimpedance amplifier for providing an amplified voltage signal. Detector electronics include a preamplifier circuit having a first and second transimpedance amplifier coupled to receive a current signal from a first and second location on a detector, respectively, and generate a first and second voltage signal at respective outputs. A second amplification stage has an input coupled to an output of the transimpedance amplifiers for amplifying the first and said second voltage signals to provide first and second amplified voltage signals. A differential output stage is coupled to the second amplification stage for receiving the first and second amplified voltage signals and providing a pair of outputs from each of the first and second amplified voltage signals. Read out circuitry has an input coupled to receive both of the pair of outputs, the read out circuitry having structure for processing each of the pair of outputs, and providing a single digital output having a time-stamp therefrom.

  13. Radiation detection system

    DOEpatents

    Riedel, Richard A [Knoxville, TN; Wintenberg, Alan L [Knoxville, TN; Clonts, Lloyd G [Knoxville, TN; Cooper, Ronald G [Oak Ridge, TN

    2012-02-14

    A preamplifier circuit for processing a signal provided by a radiation detector includes a transimpedance amplifier coupled to receive a current signal from a detector and generate a voltage signal at its output. A second amplification stage has an input coupled to an output of the transimpedance amplifier for providing an amplified voltage signal. Detector electronics include a preamplifier circuit having a first and second transimpedance amplifier coupled to receive a current signal from a first and second location on a detector, respectively, and generate a first and second voltage signal at respective outputs. A second amplification stage has an input coupled to an output of the transimpedance amplifiers for amplifying the first and said second voltage signals to provide first and second amplified voltage signals. A differential output stage is coupled to the second amplification stage for receiving the first and second amplified voltage signals and providing a pair of outputs from each of the first and second amplified voltage signals. Read out circuitry has an input coupled to receive both of the pair of outputs, the read out circuitry having structure for processing each of the pair of outputs, and providing a single digital output having a time-stamp therefrom.

  14. Interlayer excitons in a bulk van der Waals semiconductor.

    PubMed

    Arora, Ashish; Drüppel, Matthias; Schmidt, Robert; Deilmann, Thorsten; Schneider, Robert; Molas, Maciej R; Marauhn, Philipp; Michaelis de Vasconcellos, Steffen; Potemski, Marek; Rohlfing, Michael; Bratschitsch, Rudolf

    2017-09-21

    Bound electron-hole pairs called excitons govern the electronic and optical response of many organic and inorganic semiconductors. Excitons with spatially displaced wave functions of electrons and holes (interlayer excitons) are important for Bose-Einstein condensation, superfluidity, dissipationless current flow, and the light-induced exciton spin Hall effect. Here we report on the discovery of interlayer excitons in a bulk van der Waals semiconductor. They form due to strong localization and spin-valley coupling of charge carriers. By combining high-field magneto-reflectance experiments and ab initio calculations for 2H-MoTe 2 , we explain their salient features: the positive sign of the g-factor and the large diamagnetic shift. Our investigations solve the long-standing puzzle of positive g-factors in transition metal dichalcogenides, and pave the way for studying collective phenomena in these materials at elevated temperatures.Excitons, quasi-particles of bound electron-hole pairs, are at the core of the optoelectronic properties of layered transition metal dichalcogenides. Here, the authors unveil the presence of interlayer excitons in bulk van der Waals semiconductors, arising from strong localization and spin-valley coupling of charge carriers.

  15. Spin-correlated doublet pairs as intermediate states in charge separation processes

    NASA Astrophysics Data System (ADS)

    Kraffert, Felix; Behrends, Jan

    2017-10-01

    Spin-correlated charge-carrier pairs play a crucial role as intermediate states in charge separation both in natural photosynthesis as well as in solar cells. Using transient electron paramagnetic resonance (trEPR) spectroscopy in combination with spectral simulations, we study spin-correlated polaron pairs in polymer:fullerene blends as organic solar cells materials. The semi-analytical simulations presented here are based on the well-established theoretical description of spin-correlated radical pairs in biological systems, however, explicitly considering the disordered nature of polymer:fullerene blends. The large degree of disorder leads to the fact that many different relative orientations between both polarons forming the spin-correlated pairs have to be taken into account. This has important implications for the spectra, which differ significantly from those of spin-correlated radical pairs with a fixed relative orientation. We systematically study the influence of exchange and dipolar couplings on the trEPR spectra and compare the simulation results to measured X- and Q-band trEPR spectra. Our results demonstrate that assuming dipolar couplings alone does not allow us to reproduce the experimental spectra. Due to the rather delocalised nature of polarons in conjugated organic semiconductors, a significant isotropic exchange coupling needs to be included to achieve good agreement between experiments and simulations.

  16. High spectral purity silicon ring resonator photon-pair source

    NASA Astrophysics Data System (ADS)

    Steidle, Jeffrey A.; Fanto, Michael L.; Tison, Christopher C.; Wang, Zihao; Preble, Stefan F.; Alsing, Paul M.

    2015-05-01

    Here we present the experimental demonstration of a Silicon ring resonator photon-pair source. The crystalline Silicon ring resonator (radius of 18.5μm) was designed to realize low dispersion across multiple resonances, which allows for operation with a high quality factor of Q~50k. In turn, the source exhibits very high brightness of >3x105 photons/s/mW2/GHz since the produced photon pairs have a very narrow bandwidth. Furthermore, the waveguidefiber coupling loss was minimized to <1.5dB using an inverse tapered waveguide (tip width of ~150nm over a 300μm length) that is butt-coupled to a high-NA fiber (Nufern UHNA-7). This ensured minimal loss of photon pairs to the detectors, which enabled very high purity photon pairs with minimal noise, as exhibited by a very high Coincidental-Accidental Ratio of >1900. The low coupling loss (3dB fiber-fiber) also allowed for operation with very low off-chip pump power of <200μW. In addition, the zero dispersion of the ring resonator resulted in the production of a photon-pair comb across multiple resonances symmetric about the pump resonance (every ~5nm spanning >20nm), which could be used in future wavelength division multiplexed quantum networks.

  17. NMR scalar couplings across Watson–Crick base pair hydrogen bonds in DNA observed by transverse relaxation-optimized spectroscopy

    PubMed Central

    Pervushin, Konstantin; Ono, Akira; Fernández, César; Szyperski, Thomas; Kainosho, Masatsune; Wüthrich, Kurt

    1998-01-01

    This paper describes the NMR observation of 15N—15N and 1H—15N scalar couplings across the hydrogen bonds in Watson–Crick base pairs in a DNA duplex, hJNN and hJHN. These couplings represent new parameters of interest for both structural studies of DNA and theoretical investigations into the nature of the hydrogen bonds. Two dimensional [15N,1H]-transverse relaxation-optimized spectroscopy (TROSY) with a 15N-labeled 14-mer DNA duplex was used to measure hJNN, which is in the range 6–7 Hz, and the two-dimensional hJNN-correlation-[15N,1H]-TROSY experiment was used to correlate the chemical shifts of pairs of hydrogen bond-related 15N spins and to observe, for the first time, hJHN scalar couplings, with values in the range 2–3.6 Hz. TROSY-based studies of scalar couplings across hydrogen bonds should be applicable for large molecular sizes, including protein-bound nucleic acids. PMID:9826668

  18. Microscopic analysis of shape transition in neutron-deficient Yb isotopes

    NASA Astrophysics Data System (ADS)

    Fu, Y.; Tong, H.; Wang, X. F.; Wang, H.; Wang, D. Q.; Wang, X. Y.; Yao, J. M.

    2018-01-01

    The development of nuclear collectivity in even-even Yb-170152 is studied with three types of mean-field calculations: the nonrelativistic Hartree-Fock plus BCS calculation using the Skyrme SLy4 force plus a density-dependent δ pairing force and the relativistic mean-field calculation using a point-coupling energy functional supplemented with either a density-independent δ pairing force or a separable pairing force. The low-lying states are obtained by solving a five-dimensional collective Hamiltonian with parameters determined from the three mean-field solutions. The energy surfaces, excitation energies, electric multiple transition strengths, and differential isotope shifts are presented in comparison with available data. Our results show that different treatments of pairing correlations have a significant influence on the speed of developing collectivity as the increase of neutron number. All the calculations demonstrate the important role of dynamic shape-mixing effects in resolving the puzzle in the dramatic increase of charge radius from 152Yb to 154Yb and the role of triaxiality in Yb 160 ,162 ,164 .

  19. Sparse maps—A systematic infrastructure for reduced-scaling electronic structure methods. II. Linear scaling domain based pair natural orbital coupled cluster theory

    NASA Astrophysics Data System (ADS)

    Riplinger, Christoph; Pinski, Peter; Becker, Ute; Valeev, Edward F.; Neese, Frank

    2016-01-01

    Domain based local pair natural orbital coupled cluster theory with single-, double-, and perturbative triple excitations (DLPNO-CCSD(T)) is a highly efficient local correlation method. It is known to be accurate and robust and can be used in a black box fashion in order to obtain coupled cluster quality total energies for large molecules with several hundred atoms. While previous implementations showed near linear scaling up to a few hundred atoms, several nonlinear scaling steps limited the applicability of the method for very large systems. In this work, these limitations are overcome and a linear scaling DLPNO-CCSD(T) method for closed shell systems is reported. The new implementation is based on the concept of sparse maps that was introduced in Part I of this series [P. Pinski, C. Riplinger, E. F. Valeev, and F. Neese, J. Chem. Phys. 143, 034108 (2015)]. Using the sparse map infrastructure, all essential computational steps (integral transformation and storage, initial guess, pair natural orbital construction, amplitude iterations, triples correction) are achieved in a linear scaling fashion. In addition, a number of additional algorithmic improvements are reported that lead to significant speedups of the method. The new, linear-scaling DLPNO-CCSD(T) implementation typically is 7 times faster than the previous implementation and consumes 4 times less disk space for large three-dimensional systems. For linear systems, the performance gains and memory savings are substantially larger. Calculations with more than 20 000 basis functions and 1000 atoms are reported in this work. In all cases, the time required for the coupled cluster step is comparable to or lower than for the preceding Hartree-Fock calculation, even if this is carried out with the efficient resolution-of-the-identity and chain-of-spheres approximations. The new implementation even reduces the error in absolute correlation energies by about a factor of two, compared to the already accurate previous implementation.

  20. Distressed Couples and Marriage Education

    ERIC Educational Resources Information Center

    DeMaria, Rita M.

    2005-01-01

    Professionals generally believe that couples who choose to attend marriage education programs are not as distressed as are clinical couples and that distressed couples are not good candidates for marriage education. We examined these assumptions in 129 married couples who enrolled in a PAIRS, Practical Application of Intimate Relationship Skills…

  1. Molecular dynamics simulations and statistical coupling analysis reveal functional coevolution network of oncogenic mutations in the CDKN2A-CDK6 complex.

    PubMed

    Wang, Jingwen; Zhao, Yuqi; Wang, Yanjie; Huang, Jingfei

    2013-01-16

    Coevolution between proteins is crucial for understanding protein-protein interaction. Simultaneous changes allow a protein complex to maintain its overall structural-functional integrity. In this study, we combined statistical coupling analysis (SCA) and molecular dynamics simulations on the CDK6-CDKN2A protein complex to evaluate coevolution between proteins. We reconstructed an inter-protein residue coevolution network, consisting of 37 residues and 37 interactions. It shows that most of the coevolved residue pairs are spatially proximal. When the mutations happened, the stable local structures were broken up and thus the protein interaction was decreased or inhibited, with a following increased risk of melanoma. The identification of inter-protein coevolved residues in the CDK6-CDKN2A complex can be helpful for designing protein engineering experiments. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  2. The energy separation between the classical and nonclassical isomers of protonated acetylene - An extensive study in one- and n-particle space saturation

    NASA Technical Reports Server (NTRS)

    Lindh, Roland; Rice, Julia E.; Lee, Timothy J.

    1991-01-01

    The energy separation between the classical and nonclassical forms of protonated acetylene has been reinvestigated in light of the recent experimentally deduced lower bound to this value of 6.0 kcal/mol. The objective of the present study is to use state-of-the-art ab initio quantum mechanical methods to establish this energy difference to within chemical accuracy (i.e., about 1 kcal/mol). The one-particle basis sets include up to g-type functions and the electron correlation methods include single and double excitation coupled-cluster (CCSD), the CCSD(T) extension, multireference configuration interaction, and the averaged coupled-pair functional methods. A correction for zero-point vibrational energies has also been included, yielding a best estimate for the energy difference between the classical and nonclassical forms of 3.7 + or - 1.3 kcal/mol.

  3. Adsorption of ion pairs onto graphene flakes and impacts of counterions during the adsorption processes

    NASA Astrophysics Data System (ADS)

    Zhu, Chang; Yun, Jiena; Wang, Qian; Yang, Gang

    2018-03-01

    Although cations and anions are two integral constituents for all electrolytes, adsorption of ion pairs onto carbonaceous materials gains obviously less attention than adsorption of only cations or anions. Here DFT calculations are employed finding that four adsorption configurations emerge for KI onto graphene flakes (GF) instead of three for the other ion pairs. Reservation of ionic bonds is critical to their stabilities, and the bilateral configurations, where GFs couple with both cations and anions, are disfavored due to rupture of ionic bonds. Relative stabilities of two vertical configurations can be regulated and even reversed through edge-functionalization. Surprisingly, the horizontal adsorption configurations, which are global energy minima as long as present, are non-existent for a majority of ion pairs, and their existence or not is determined by the adsorption differences between halide ions and alkali ions (△Ead). Counterions effects for both cations and anions increase with the atomic electronegativities and cations correspond to stronger counterion effects; e.g., Li+ added on the other side of GFs promotes the adsorption of F- more pronouncedly than edge-functionalization. Mechanisms of electron transfers are also discussed, and three alteration patterns by counterions are observed for each type of adsorption configurations. Furthermore, addition of counterions causes band gaps to vary within a wider range that may be useful to design electronic devices.

  4. Apoferritin fibers: a new template for 1D fluorescent hybrid nanostructures

    NASA Astrophysics Data System (ADS)

    Jurado, Rocío; Castello, Fabio; Bondia, Patricia; Casado, Santiago; Flors, Cristina; Cuesta, Rafael; Domínguez-Vera, José M.; Orte, Angel; Gálvez, Natividad

    2016-05-01

    Recently, research in the field of protein amyloid fibers has gained great attention due to the use of these materials as nanoscale templates for the construction of functional hybrid materials. The formation of apoferritin amyloid-like protein fibers is demonstrated herein for the first time. The morphology, size and stiffness of these one-dimensional structures are comparable to the fibers formed by β-lactoglobulin, a protein frequently used as a model in the study of amyloid-like fibrillar proteins. Nanometer-sized globular apoferritin is capable of self-assembling to form 1D micrometer-sized structures after being subjected to a heating process. Depending on the experimental conditions, fibers with different morphologies and sizes are obtained. The wire-like protein structure is rich in functional groups and allows chemical functionalization with diverse quantum dots (QD), as well as with different Alexa Fluor (AF) dyes, leading to hybrid fluorescent fibers with variable emission wavelengths, from green to near infrared, depending on the QD and AFs coupled. For fibers containing the pair AF488 and AF647, efficient fluorescence energy transfer from the covalently coupled donor (AF488) to acceptor tags (AF647) takes place. Apoferritin fibers are proposed here as a new promising template for obtaining hybrid functional materials.Recently, research in the field of protein amyloid fibers has gained great attention due to the use of these materials as nanoscale templates for the construction of functional hybrid materials. The formation of apoferritin amyloid-like protein fibers is demonstrated herein for the first time. The morphology, size and stiffness of these one-dimensional structures are comparable to the fibers formed by β-lactoglobulin, a protein frequently used as a model in the study of amyloid-like fibrillar proteins. Nanometer-sized globular apoferritin is capable of self-assembling to form 1D micrometer-sized structures after being subjected to a heating process. Depending on the experimental conditions, fibers with different morphologies and sizes are obtained. The wire-like protein structure is rich in functional groups and allows chemical functionalization with diverse quantum dots (QD), as well as with different Alexa Fluor (AF) dyes, leading to hybrid fluorescent fibers with variable emission wavelengths, from green to near infrared, depending on the QD and AFs coupled. For fibers containing the pair AF488 and AF647, efficient fluorescence energy transfer from the covalently coupled donor (AF488) to acceptor tags (AF647) takes place. Apoferritin fibers are proposed here as a new promising template for obtaining hybrid functional materials. Electronic supplementary information (ESI) available: TEM images of ferritin protein fiber formation, and apoferritin after 18 days of heat treatment; FLIM-PIE technique details; fluorescence emission spectra of apoferritin and β-lactoglobulin fibers functionalized with different QDs. See DOI: 10.1039/c6nr01044j

  5. The p-wave superconductivity in the presence of Rashba interaction in 2DEG

    PubMed Central

    Weng, Ke-Chuan; Hu, C. D.

    2016-01-01

    We investigate the effect of the Rashba interaction on two dimensional superconductivity. The presence of the Rashba interaction lifts the spin degeneracy and gives rise to the spectrum of two bands. There are intraband and interband pairs scattering which result in the coupled gap equations. We find that there are isotropic and anisotropic components in the gap function. The latter has the form of cos φk where . The former is suppressed because the intraband and the interband scatterings nearly cancel each other. Hence, −the system should exhibit the p-wave superconductivity. We perform a detailed study of electron-phonon interaction for 2DEG and find that, if only normal processes are considered, the effective coupling strength constant of this new superconductivity is about one-half of the s-wave case in the ordinary 2DEG because of the angular average of the additional in the anisotropic gap function. By taking into account of Umklapp processes, we find they are the major contribution in the electron-phonon coupling in superconductivity and enhance the transition temperature Tc. PMID:27459677

  6. Implicit Multisensory Associations Influence Voice Recognition

    PubMed Central

    von Kriegstein, Katharina; Giraud, Anne-Lise

    2006-01-01

    Natural objects provide partially redundant information to the brain through different sensory modalities. For example, voices and faces both give information about the speech content, age, and gender of a person. Thanks to this redundancy, multimodal recognition is fast, robust, and automatic. In unimodal perception, however, only part of the information about an object is available. Here, we addressed whether, even under conditions of unimodal sensory input, crossmodal neural circuits that have been shaped by previous associative learning become activated and underpin a performance benefit. We measured brain activity with functional magnetic resonance imaging before, while, and after participants learned to associate either sensory redundant stimuli, i.e. voices and faces, or arbitrary multimodal combinations, i.e. voices and written names, ring tones, and cell phones or brand names of these cell phones. After learning, participants were better at recognizing unimodal auditory voices that had been paired with faces than those paired with written names, and association of voices with faces resulted in an increased functional coupling between voice and face areas. No such effects were observed for ring tones that had been paired with cell phones or names. These findings demonstrate that brief exposure to ecologically valid and sensory redundant stimulus pairs, such as voices and faces, induces specific multisensory associations. Consistent with predictive coding theories, associative representations become thereafter available for unimodal perception and facilitate object recognition. These data suggest that for natural objects effective predictive signals can be generated across sensory systems and proceed by optimization of functional connectivity between specialized cortical sensory modules. PMID:17002519

  7. Exotic s-wave superconductivity in alkali-doped fullerides.

    PubMed

    Nomura, Yusuke; Sakai, Shiro; Capone, Massimo; Arita, Ryotaro

    2016-04-20

    Alkali-doped fullerides (A3C60 with A = K, Rb, Cs) show a surprising phase diagram, in which a high transition-temperature (Tc) s-wave superconducting state emerges next to a Mott insulating phase as a function of the lattice spacing. This is in contrast with the common belief that Mott physics and phonon-driven s-wave superconductivity are incompatible, raising a fundamental question on the mechanism of the high-Tc superconductivity. This article reviews recent ab initio calculations, which have succeeded in reproducing comprehensively the experimental phase diagram with high accuracy and elucidated an unusual cooperation between the electron-phonon coupling and the electron-electron interactions leading to Mott localization to realize an unconventional s-wave superconductivity in the alkali-doped fullerides. A driving force behind the exotic physics is unusual intramolecular interactions, characterized by the coexistence of a strongly repulsive Coulomb interaction and a small effectively negative exchange interaction. This is realized by a subtle energy balance between the coupling with the Jahn-Teller phonons and Hund's coupling within the C60 molecule. The unusual form of the interaction leads to a formation of pairs of up- and down-spin electrons on the molecules, which enables the s-wave pairing. The emergent superconductivity crucially relies on the presence of the Jahn-Teller phonons, but surprisingly benefits from the strong correlations because the correlations suppress the kinetic energy of the electrons and help the formation of the electron pairs, in agreement with previous model calculations. This confirms that the alkali-doped fullerides are a new type of unconventional superconductors, where the unusual synergy between the phonons and Coulomb interactions drives the high-Tc superconductivity.

  8. Current hormonal contraceptive use predicts female extra-pair and dyadic sexual behavior: evidence based on Czech National Survey data.

    PubMed

    Klapilová, Kateřina; Cobey, Kelly D; Wells, Timothy; Roberts, S Craig; Weiss, Petr; Havlíček, Jan

    2014-01-10

    Data from 1155 Czech women (493 using oral contraception, 662 non-users), obtained from the Czech National Survey of Sexual Behavior, were used to investigate evolutionary-based hypotheses concerning the predictive value of current oral contraceptive (OC) use on extra-pair and dyadic (in-pair) sexual behavior of coupled women. Specifically, the aim was to determine whether current OC use was associated with lower extra-pair and higher in-pair sexual interest and behavior, because OC use suppresses cyclical shifts in mating psychology that occur in normally cycling women. Zero-inflated Poisson (ZIP) regression and negative binomial models were used to test associations between OC use and these sexual measures, controlling for other relevant predictors (e.g., age, parity, in-pair sexual satisfaction, relationship length). The overall incidence of having had an extra-pair partner or one-night stand in the previous year was not related to current OC use (the majority of the sample had not). However, among the women who had engaged in extra-pair sexual behavior, OC users had fewer one-night stands than non-users, and tended to have fewer partners, than non-users. OC users also had more frequent dyadic intercourse than non-users, potentially indicating higher commitment to their current relationship. These results suggest that suppression of fertility through OC use may alter important aspects of female sexual behavior, with potential implications for relationship functioning and stability.

  9. Efficient creation of dipolar coupled nitrogen-vacancy spin qubits in diamond

    NASA Astrophysics Data System (ADS)

    Jakobi, I.; Momenzadeh, S. A.; Fávaro de Oliveira, F.; Michl, J.; Ziem, F.; Schreck, M.; Neumann, P.; Denisenko, A.; Wrachtrup, J.

    2016-09-01

    Coherently coupled pairs or multimers of nitrogen-vacancy defect electron spins in diamond have many promising applications especially in quantum information processing (QIP) but also in nanoscale sensing applications. Scalable registers of spin qubits are essential to the progress of QIP. Ion implantation is the only known technique able to produce defect pairs close enough to allow spin coupling via dipolar interaction. Although several competing methods have been proposed to increase the resulting resolution of ion implantation, the reliable creation of working registers is still to be demonstrated. The current limitation are residual radiation-induced defects, resulting in degraded qubit performance as trade-off for positioning accuracy. Here we present an optimized estimation of nanomask implantation parameters that are most likely to produce interacting qubits under standard conditions. We apply our findings to a well-established technique, namely masks written in electron-beam lithography, to create coupled defect pairs with a reasonable probability. Furthermore, we investigate the scaling behavior and necessary improvements to efficiently engineer interacting spin architectures.

  10. Negative coupled inductors for polyphase choppers

    NASA Technical Reports Server (NTRS)

    Jamieson, Robert S. (Inventor)

    1984-01-01

    A technique for negatively coupling the outputs of polyphase choppers is disclosed, wherein the output inductance of each phase is divided into two windings, and each winding is negatively coupled to a corresponding winding of a neighboring phase. In a preferred embodiment for a three-phase chopper circuit, the output inductance of phase A is divided into windings 100 and 102, the output inductance of phase B is divided into windings 110 and 112, and the output inductance of phase C is divided into windings 120 and 122. Pairs of windings 100 and 110, 112 and 120, and 102 and 122 are respectively disposed in transformers arranged for negatively coupling the windings of each pair.

  11. Employing conservation of co-expression to improve functional inference

    PubMed Central

    Daub, Carsten O; Sonnhammer, Erik LL

    2008-01-01

    Background Observing co-expression between genes suggests that they are functionally coupled. Co-expression of orthologous gene pairs across species may improve function prediction beyond the level achieved in a single species. Results We used orthology between genes of the three different species S. cerevisiae, D. melanogaster, and C. elegans to combine co-expression across two species at a time. This led to increased function prediction accuracy when we incorporated expression data from either of the other two species and even further increased when conservation across both of the two other species was considered at the same time. Employing the conservation across species to incorporate abundant model organism data for the prediction of protein interactions in poorly characterized species constitutes a very powerful annotation method. Conclusion To be able to employ the most suitable co-expression distance measure for our analysis, we evaluated the ability of four popular gene co-expression distance measures to detect biologically relevant interactions between pairs of genes. For the expression datasets employed in our co-expression conservation analysis above, we used the GO and the KEGG PATHWAY databases as gold standards. While the differences between distance measures were small, Spearman correlation showed to give most robust results. PMID:18808668

  12. Systems level analysis of the Chlamydomonas reinhardtii metabolic network reveals variability in evolutionary co-conservation

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

    Chaiboonchoe, Amphun; Ghamsari, Lila; Dohai, Bushra

    Metabolic networks, which are mathematical representations of organismal metabolism, are reconstructed to provide computational platforms to guide metabolic engineering experiments and explore fundamental questions on metabolism. Systems level analyses, such as interrogation of phylogenetic relationships within the network, can provide further guidance on the modification of metabolic circuitries. Chlamydomonas reinhardtii, a biofuel relevant green alga that has retained key genes with plant, animal, and protist affinities, serves as an ideal model organism to investigate the interplay between gene function and phylogenetic affinities at multiple organizational levels. Here, using detailed topological and functional analyses, coupled with transcriptomics studies on a metabolicmore » network that we have reconstructed for C. reinhardtii, we show that network connectivity has a significant concordance with the co-conservation of genes; however, a distinction between topological and functional relationships is observable within the network. Dynamic and static modes of co-conservation were defined and observed in a subset of gene-pairs across the network topologically. In contrast, genes with predicted synthetic interactions, or genes involved in coupled reactions, show significant enrichment for both shorter and longer phylogenetic distances. Based on our results, we propose that the metabolic network of C. reinhardtii is assembled with an architecture to minimize phylogenetic profile distances topologically, while it includes an expansion of such distances for functionally interacting genes. This arrangement may increase the robustness of C. reinhardtii's network in dealing with varied environmental challenges that the species may face. As a result, the defined evolutionary constraints within the network, which identify important pairings of genes in metabolism, may offer guidance on synthetic biology approaches to optimize the production of desirable metabolites.« less

  13. Systems level analysis of the Chlamydomonas reinhardtii metabolic network reveals variability in evolutionary co-conservation.

    PubMed

    Chaiboonchoe, Amphun; Ghamsari, Lila; Dohai, Bushra; Ng, Patrick; Khraiwesh, Basel; Jaiswal, Ashish; Jijakli, Kenan; Koussa, Joseph; Nelson, David R; Cai, Hong; Yang, Xinping; Chang, Roger L; Papin, Jason; Yu, Haiyuan; Balaji, Santhanam; Salehi-Ashtiani, Kourosh

    2016-07-19

    Metabolic networks, which are mathematical representations of organismal metabolism, are reconstructed to provide computational platforms to guide metabolic engineering experiments and explore fundamental questions on metabolism. Systems level analyses, such as interrogation of phylogenetic relationships within the network, can provide further guidance on the modification of metabolic circuitries. Chlamydomonas reinhardtii, a biofuel relevant green alga that has retained key genes with plant, animal, and protist affinities, serves as an ideal model organism to investigate the interplay between gene function and phylogenetic affinities at multiple organizational levels. Here, using detailed topological and functional analyses, coupled with transcriptomics studies on a metabolic network that we have reconstructed for C. reinhardtii, we show that network connectivity has a significant concordance with the co-conservation of genes; however, a distinction between topological and functional relationships is observable within the network. Dynamic and static modes of co-conservation were defined and observed in a subset of gene-pairs across the network topologically. In contrast, genes with predicted synthetic interactions, or genes involved in coupled reactions, show significant enrichment for both shorter and longer phylogenetic distances. Based on our results, we propose that the metabolic network of C. reinhardtii is assembled with an architecture to minimize phylogenetic profile distances topologically, while it includes an expansion of such distances for functionally interacting genes. This arrangement may increase the robustness of C. reinhardtii's network in dealing with varied environmental challenges that the species may face. The defined evolutionary constraints within the network, which identify important pairings of genes in metabolism, may offer guidance on synthetic biology approaches to optimize the production of desirable metabolites.

  14. Systems level analysis of the Chlamydomonas reinhardtii metabolic network reveals variability in evolutionary co-conservation

    DOE PAGES

    Chaiboonchoe, Amphun; Ghamsari, Lila; Dohai, Bushra; ...

    2016-06-14

    Metabolic networks, which are mathematical representations of organismal metabolism, are reconstructed to provide computational platforms to guide metabolic engineering experiments and explore fundamental questions on metabolism. Systems level analyses, such as interrogation of phylogenetic relationships within the network, can provide further guidance on the modification of metabolic circuitries. Chlamydomonas reinhardtii, a biofuel relevant green alga that has retained key genes with plant, animal, and protist affinities, serves as an ideal model organism to investigate the interplay between gene function and phylogenetic affinities at multiple organizational levels. Here, using detailed topological and functional analyses, coupled with transcriptomics studies on a metabolicmore » network that we have reconstructed for C. reinhardtii, we show that network connectivity has a significant concordance with the co-conservation of genes; however, a distinction between topological and functional relationships is observable within the network. Dynamic and static modes of co-conservation were defined and observed in a subset of gene-pairs across the network topologically. In contrast, genes with predicted synthetic interactions, or genes involved in coupled reactions, show significant enrichment for both shorter and longer phylogenetic distances. Based on our results, we propose that the metabolic network of C. reinhardtii is assembled with an architecture to minimize phylogenetic profile distances topologically, while it includes an expansion of such distances for functionally interacting genes. This arrangement may increase the robustness of C. reinhardtii's network in dealing with varied environmental challenges that the species may face. As a result, the defined evolutionary constraints within the network, which identify important pairings of genes in metabolism, may offer guidance on synthetic biology approaches to optimize the production of desirable metabolites.« less

  15. Superconductivity in three-dimensional spin-orbit coupled semimetals

    NASA Astrophysics Data System (ADS)

    Savary, Lucile; Ruhman, Jonathan; Venderbos, Jörn W. F.; Fu, Liang; Lee, Patrick A.

    2017-12-01

    Motivated by the experimental detection of superconductivity in the low-carrier density half-Heusler compound YPtBi, we study the pairing instabilities of three-dimensional strongly spin-orbit coupled semimetals with a quadratic band touching point. In these semimetals the electronic structure at the Fermi energy is described by spin j =3/2 quasiparticles, which are fundamentally different from those in ordinary metals with spin j =1/2 . For both local and nonlocal pairing channels in j =3/2 materials we develop a general approach to analyzing pairing instabilities, thereby providing the computational tools needed to investigate the physics of these systems beyond phenomenological considerations. Furthermore, applying our method to a generic density-density interaction, we establish that: (i) The pairing strengths in the different symmetry channels uniquely encode the j =3/2 nature of the Fermi surface band structure—a manifestation of the fundamental difference with ordinary metals. (ii) The leading odd-parity pairing instabilities are different for electron doping and hole doping. Finally, we argue that polar phonons, i.e., Coulomb interactions mediated by the long-ranged electric polarization of the optical phonon modes, provide a coupling strength large enough to account for a Kelvin-range transition temperature in the s -wave channel, and are likely to play an important role in the overall attraction in non-s -wave channels. Moreover, the explicit calculation of the coupling strengths allows us to conclude that the two largest non-s -wave contributions occur in nonlocal channels, in contrast with what has been commonly assumed.

  16. Reciprocating linear motor

    NASA Technical Reports Server (NTRS)

    Goldowsky, Michael P. (Inventor)

    1987-01-01

    A reciprocating linear motor is formed with a pair of ring-shaped permanent magnets having opposite radial polarizations, held axially apart by a nonmagnetic yoke, which serves as an axially displaceable armature assembly. A pair of annularly wound coils having axial lengths which differ from the axial lengths of the permanent magnets are serially coupled together in mutual opposition and positioned with an outer cylindrical core in axial symmetry about the armature assembly. One embodiment includes a second pair of annularly wound coils serially coupled together in mutual opposition and an inner cylindrical core positioned in axial symmetry inside the armature radially opposite to the first pair of coils. Application of a potential difference across a serial connection of the two pairs of coils creates a current flow perpendicular to the magnetic field created by the armature magnets, thereby causing limited linear displacement of the magnets relative to the coils.

  17. A tachykinin-like neuroendocrine signalling axis couples central serotonin action and nutrient sensing with peripheral lipid metabolism

    PubMed Central

    Palamiuc, Lavinia; Noble, Tallie; Witham, Emily; Ratanpal, Harkaranveer; Vaughan, Megan; Srinivasan, Supriya

    2017-01-01

    Serotonin, a central neuromodulator with ancient ties to feeding and metabolism, is a major driver of body fat loss. However, mechanisms by which central serotonin action leads to fat loss remain unknown. Here, we report that the FLP-7 neuropeptide and its cognate receptor, NPR-22, function as the ligand-receptor pair that defines the neuroendocrine axis of serotonergic body fat loss in Caenorhabditis elegans. FLP-7 is secreted as a neuroendocrine peptide in proportion to fluctuations in neural serotonin circuit functions, and its release is regulated from secretory neurons via the nutrient sensor AMPK. FLP-7 acts via the NPR-22/Tachykinin2 receptor in the intestine and drives fat loss via the adipocyte triglyceride lipase ATGL-1. Importantly, this ligand-receptor pair does not alter other serotonin-dependent behaviours including food intake. For global modulators such as serotonin, the use of distinct neuroendocrine peptides for each output may be one means to achieve phenotypic selectivity. PMID:28128367

  18. Quantifying Environmental Effects on the Decay of Hole Transfer Couplings in Biosystems.

    PubMed

    Ramos, Pablo; Pavanello, Michele

    2014-06-10

    In the past two decades, many research groups worldwide have tried to understand and categorize simple regimes in the charge transfer of such biological systems as DNA. Theoretically speaking, the lack of exact theories for electron-nuclear dynamics on one side and poor quality of the parameters needed by model Hamiltonians and nonadiabatic dynamics alike (such as couplings and site energies) on the other are the two main difficulties for an appropriate description of the charge transfer phenomena. In this work, we present an application of a previously benchmarked and linear-scaling subsystem density functional theory (DFT) method for the calculation of couplings, site energies, and superexchange decay factors (β) of several biological donor-acceptor dyads, as well as double stranded DNA oligomers composed of up to five base pairs. The calculations are all-electron and provide a clear view of the role of the environment on superexchange couplings in DNA-they follow experimental trends and confirm previous semiempirical calculations. The subsystem DFT method is proven to be an excellent tool for long-range, bridge-mediated coupling and site energy calculations of embedded molecular systems.

  19. TSKS concentrates in spermatid centrioles during flagellogenesis.

    PubMed

    Xu, Bingfang; Hao, Zhonglin; Jha, Kula N; Zhang, Zhibing; Urekar, Craig; Digilio, Laura; Pulido, Silvia; Strauss, Jerome F; Flickinger, Charles J; Herr, John C

    2008-07-15

    Centrosomal coiled-coil proteins paired with kinases play critical roles in centrosomal functions within somatic cells, however knowledge regarding gamete centriolar proteins is limited. In this study, the substrate of TSSK1 and 2, TSKS, was localized during spermiogenesis to the centrioles of post-meiotic spermatids, where it reached its greatest concentration during the period of flagellogenesis. This centriolar localization persisted in ejaculated human spermatozoa, while centriolar TSKS diminished in mouse sperm, where centrioles are known to undergo complete degeneration. In addition to the centriolar localization during flagellogenesis, mouse TSKS and the TSSK2 kinase localized in the tail and acrosomal regions of mouse epididymal sperm, while TSSK2 was found in the equatorial segment, neck and the midpiece of human spermatozoa. TSSK2/TSKS is the first kinase/substrate pair localized to the centrioles of spermatids and spermatozoa. Coupled with the infertility due to haploinsufficiency noted in chimeric mice with deletion of Tssk1 and 2 (companion paper) this centriolar kinase/substrate pair is predicted to play an indispensable role during spermiogenesis.

  20. High-Precision Differential Predictions for Top-Quark Pairs at the LHC

    NASA Astrophysics Data System (ADS)

    Czakon, Michal; Heymes, David; Mitov, Alexander

    2016-02-01

    We present the first complete next-to-next-to-leading order (NNLO) QCD predictions for differential distributions in the top-quark pair production process at the LHC. Our results are derived from a fully differential partonic Monte Carlo calculation with stable top quarks which involves no approximations beyond the fixed-order truncation of the perturbation series. The NNLO corrections improve the agreement between existing LHC measurements [V. Khachatryan et al. (CMS Collaboration), Eur. Phys. J. C 75, 542 (2015)] and standard model predictions for the top-quark transverse momentum distribution, thus helping alleviate one long-standing discrepancy. The shape of the top-quark pair invariant mass distribution turns out to be stable with respect to radiative corrections beyond NLO which increases the value of this observable as a place to search for physics beyond the standard model. The results presented here provide essential input for parton distribution function fits, implementation of higher-order effects in Monte Carlo generators, as well as top-quark mass and strong coupling determination.

  1. High-Precision Differential Predictions for Top-Quark Pairs at the LHC.

    PubMed

    Czakon, Michal; Heymes, David; Mitov, Alexander

    2016-02-26

    We present the first complete next-to-next-to-leading order (NNLO) QCD predictions for differential distributions in the top-quark pair production process at the LHC. Our results are derived from a fully differential partonic Monte Carlo calculation with stable top quarks which involves no approximations beyond the fixed-order truncation of the perturbation series. The NNLO corrections improve the agreement between existing LHC measurements [V. Khachatryan et al. (CMS Collaboration), Eur. Phys. J. C 75, 542 (2015)] and standard model predictions for the top-quark transverse momentum distribution, thus helping alleviate one long-standing discrepancy. The shape of the top-quark pair invariant mass distribution turns out to be stable with respect to radiative corrections beyond NLO which increases the value of this observable as a place to search for physics beyond the standard model. The results presented here provide essential input for parton distribution function fits, implementation of higher-order effects in Monte Carlo generators, as well as top-quark mass and strong coupling determination.

  2. A bioinspired redox relay that mimics radical interactions of the Tyr-His pairs of photosystem II

    NASA Astrophysics Data System (ADS)

    Megiatto, Jackson D., Jr.; Méndez-Hernández, Dalvin D.; Tejeda-Ferrari, Marely E.; Teillout, Anne-Lucie; Llansola-Portolés, Manuel J.; Kodis, Gerdenis; Poluektov, Oleg G.; Rajh, Tijana; Mujica, Vladimiro; Groy, Thomas L.; Gust, Devens; Moore, Thomas A.; Moore, Ana L.

    2014-05-01

    In water-oxidizing photosynthetic organisms, light absorption generates a powerfully oxidizing chlorophyll complex (P680•+) in the photosystem II reaction centre. This is reduced via an electron transfer pathway from the manganese-containing water-oxidizing catalyst, which includes an electron transfer relay comprising a tyrosine (Tyr)-histidine (His) pair that features a hydrogen bond between a phenol group and an imidazole group. By rapidly reducing P680•+, the relay is thought to mitigate recombination reactions, thereby ensuring a high quantum yield of water oxidation. Here, we show that an artificial reaction centre that features a benzimidazole-phenol model of the Tyr-His pair mimics both the short-internal hydrogen bond in photosystem II and, using electron paramagnetic resonance spectroscopy, the thermal relaxation that accompanies proton-coupled electron transfer. Although this artificial system is much less complex than the natural one, theory suggests that it captures the essential features that are important in the function of the relay.

  3. Solid-state EPR strategies for the structural characterization of paramagnetic NO adducts of frustrated Lewis pairs (FLPs)

    NASA Astrophysics Data System (ADS)

    de Oliveira, Marcos; Wiegand, Thomas; Elmer, Lisa-Maria; Sajid, Muhammad; Kehr, Gerald; Erker, Gerhard; Magon, Claudio José; Eckert, Hellmut

    2015-03-01

    Anisotropic interactions present in three new nitroxide radicals prepared by N,N addition of NO to various borane-phosphane frustrated Lewis pairs (FLPs) have been characterized by continuous-wave (cw) and pulsed X-band EPR spectroscopies in solid FLP-hydroxylamine matrices at 100 K. Anisotropic g-tensor values and 11B, 14N, and 31P hyperfine coupling tensor components have been extracted from continuous-wave lineshape analyses, electron spin echo envelope modulation (ESEEM), and hyperfine sublevel correlation spectroscopy (HYSCORE) experiments with the help of computer simulation techniques. Suitable fitting constraints are developed on the basis of density functional theory (DFT) calculations. These calculations reveal that different from the situation in standard nitroxide radicals (TEMPO), the g-tensors are non-coincident with any of the nuclear hyperfine interaction tensors. The determination of these interaction parameters turns out to be successful, as the cw- and pulse EPR experiments are highly complementary in informational content. While the continuous-wave lineshape is largely influenced by the anisotropic hyperfine coupling to 14N and 31P, the ESEEM and HYSCORE spectra contain important information about the 11B hyperfine coupling and nuclear electric quadrupolar interaction. The set of cw- and pulsed EPR experiments, with fitting constraints developed by DFT calculations, defines an efficient strategy for the structural analysis of paramagnetic FLP adducts.

  4. Solid-state EPR strategies for the structural characterization of paramagnetic NO adducts of frustrated Lewis pairs (FLPs)

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

    Oliveira, Marcos de; Magon, Claudio José; Wiegand, Thomas

    2015-03-28

    Anisotropic interactions present in three new nitroxide radicals prepared by N,N addition of NO to various borane-phosphane frustrated Lewis pairs (FLPs) have been characterized by continuous-wave (cw) and pulsed X-band EPR spectroscopies in solid FLP-hydroxylamine matrices at 100 K. Anisotropic g-tensor values and {sup 11}B, {sup 14}N, and {sup 31}P hyperfine coupling tensor components have been extracted from continuous-wave lineshape analyses, electron spin echo envelope modulation (ESEEM), and hyperfine sublevel correlation spectroscopy (HYSCORE) experiments with the help of computer simulation techniques. Suitable fitting constraints are developed on the basis of density functional theory (DFT) calculations. These calculations reveal that differentmore » from the situation in standard nitroxide radicals (TEMPO), the g-tensors are non-coincident with any of the nuclear hyperfine interaction tensors. The determination of these interaction parameters turns out to be successful, as the cw- and pulse EPR experiments are highly complementary in informational content. While the continuous-wave lineshape is largely influenced by the anisotropic hyperfine coupling to {sup 14}N and {sup 31}P, the ESEEM and HYSCORE spectra contain important information about the {sup 11}B hyperfine coupling and nuclear electric quadrupolar interaction. The set of cw- and pulsed EPR experiments, with fitting constraints developed by DFT calculations, defines an efficient strategy for the structural analysis of paramagnetic FLP adducts.« less

  5. Lineshapes of Dipole-Dipole Resonances in a Cold Rydberg Gas

    NASA Astrophysics Data System (ADS)

    Richards, B. G.; Jones, R. R.

    2015-05-01

    We have examined the lineshapes associated with Stark tuned, dipole-dipole resonances involving Rydberg atoms in a cold gas. Rb atoms in a MOT are laser excited from the 5 p level to 32p3 / 2 in the presence of a weak electric field. A fast rising electric field pulse Stark tunes the total energy of two 32 p atom pairs so it is (nearly) degenerate with that of the 32s1 / 2+33s1 / 2 states. Because of the dipole-dipole coupling, atom pairs separated by a distance R, develop 32s1 / 2+33s1 / 2 character. The maximum probability for finding atoms in s-states depends on the detuning from degeneracy and on the dipole-dipole coupling. We obtain the ``resonance'' lineshape by measuring, via state-selective field ionization, the s-state population as a function of the tuning field. The resonance width decreases with density due to R-3 dependence of the dipole-dipole coupling. In principle, the lineshape provides information about the distribution of Rydberg atom spacings in the sample. For equally spaced atoms, the lineshape should be Lorentzian while for a random nearest neighbor distribution it appears as a cusp. At low densities nearly Gaussian lineshapes are observed with widths that are too large to be the result of inhomogeneous electric or magnetic fields. Supported by the NSF.

  6. Characterization of the product radical structure in the Co(II)-product radical pair state of coenzyme B12-dependent ethanolamine deaminase by using three-pulse 2H ESEEM spectroscopy.

    PubMed

    Warncke, Kurt

    2005-03-08

    Molecular structural features of the product radical in the Co(II)-product radical pair catalytic intermediate state in coenzyme B(12)- (adenosylcobalamin-) dependent ethanolamine deaminase from Salmonella typhimurium have been characterized by using X-band three-pulse electron spin-echo envelope modulation (ESEEM) spectroscopy in the disordered solid state. The Co(II)-product radical pair state was prepared by cryotrapping holoenzyme during steady-state turnover on excess 1,1,2,2-(2)H(4)-aminoethanol or natural abundance, (1)H(4)-aminoethanol. Simulation of the (2)H/(1)H quotient ESEEM (obtained at two microwave frequencies, 8.9 and 10.9 GHz) from the interaction of the unpaired electron localized at C2 of the product radical with nearby (2)H nuclei requires four types of coupled (2)H, which are assigned as follows: (a) a single strongly coupled (effective dipole distance, r(eff) = 2.3 A) (2)H in the C5' methyl group of 5'-deoxyadenosine, (b) two weakly coupled (r(eff) = 4.2 A) (2)H in the C5' methyl group, (c) one (2)H coupling from a beta-(2)H bonded to C1 of the product radical (isotropic hyperfine coupling, A(iso) = 4.7 MHz), and (d) a second type of C1 beta-(2)H coupling (A(iso) = 7.7 MHz). The two beta-(2)H couplings are proposed to arise from two C1-C2 rotamer states of the product radical that are present in approximately equal proportion. A model is presented, in which C5' is positioned at a distance of 3.3 A from C2, which is comparable with the C1-C5' distance in the Co(II)-substrate radical pair intermediate. Therefore, the C5'methyl group remains in close (van der Waals) contact with the substrate and product radical species during the radical rearrangement step of the catalytic cycle, and the C5' center is the sole mediator of radical pair recombination in ethanolamine deaminase.

  7. Anomalous photon-gauge boson coupling contribution to the exclusive vector boson pair production from two photon exchange in pp collisions at 13 TeV

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

    Martins, D. E.; Vilela Pereira, A.; Sá Borges, J.

    We study the W and Z pair production from two-photon exchange in proton-proton collisions at the LHC in order to evaluate the contributions of anomalous photon-gauge boson couplings, that simulates new particles and couplings predicted in many Standard Model (SM) extensions. The experimental results of W{sup +} W{sup −} exclusive production (pp → pW{sup +}W{sup −} p) at 7 TeV from the CMS collaboration [1] updates the experimental limits on anomalous couplings obtained at the Large Electron-Positron Collider (LEP). This motivates our present analysis hopefully anticipating the expected results using the Precision Proton Spectrometer (PPS) to be installed as partmore » of CMS. In this work, we consider the W{sup +}W{sup −} exclusive production to present the p{sub T} distribution of the lepton pair corresponding to the SM signal with p{sub T} (e, μ) > 10 GeV. Next, we consider the photon-gauge boson anomalous couplings by calculating, from the FPMC and MadGraph event generators, the process γγ → W{sup +}W{sup −} from a model with gauge boson quartic couplings, by considering a 1 TeV scale for new physical effects. We present our results for an integrated luminosity of 5 fb{sup −1} at center-of-mass energy of 7 TeV and for an integrated luminosity of 100 fb{sup −1} at 13 TeV. We present our preliminary results for Z pair exclusive production from two-photon exchange with anomalous couplings, where the ZZγγ quartic coupling is absent in the SM. We calculate the total cross section for the exclusive process and present the four lepton invariant mass distribution. Finally we present an outlook for the present analysis.« less

  8. Super-Chelators for Advanced Protein Labeling in Living Cells.

    PubMed

    Gatterdam, Karl; Joest, Eike F; Dietz, Marina S; Heilemann, Mike; Tampé, Robert

    2018-05-14

    Live-cell labeling, super-resolution microscopy, single-molecule applications, protein localization, or chemically induced assembly are emerging approaches, which require specific and very small interaction pairs. The minimal disturbance of protein function is essential to derive unbiased insights into cellular processes. Herein, we define a new class of hexavalent N-nitrilotriacetic acid (hexaNTA) chelators, displaying the highest affinity and stability of all NTA-based small interaction pairs described so far. Coupled to bright organic fluorophores with fine-tuned photophysical properties, the super-chelator probes were delivered into human cells by chemically gated nanopores. These super-chelators permit kinetic profiling, multiplexed labeling of His 6 - and His 12 -tagged proteins as well as single-molecule-based super-resolution imaging. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Coincidence detection of spatially correlated photon pairs with a monolithic time-resolving detector array.

    PubMed

    Unternährer, Manuel; Bessire, Bänz; Gasparini, Leonardo; Stoppa, David; Stefanov, André

    2016-12-12

    We demonstrate coincidence measurements of spatially entangled photons by means of a multi-pixel based detection array. The sensor, originally developed for positron emission tomography applications, is a fully digital 8×16 silicon photomultiplier array allowing not only photon counting but also per-pixel time stamping of the arrived photons with an effective resolution of 265 ps. Together with a frame rate of 500 kfps, this property exceeds the capabilities of conventional charge-coupled device cameras which have become of growing interest for the detection of transversely correlated photon pairs. The sensor is used to measure a second-order correlation function for various non-collinear configurations of entangled photons generated by spontaneous parametric down-conversion. The experimental results are compared to theory.

  10. Thermodynamic Identities and Symmetry Breaking in Short-Range Spin Glasses

    NASA Astrophysics Data System (ADS)

    Arguin, L.-P.; Newman, C. M.; Stein, D. L.

    2015-10-01

    We present a technique to generate relations connecting pure state weights, overlaps, and correlation functions in short-range spin glasses. These are obtained directly from the unperturbed Hamiltonian and hold for general coupling distributions. All are satisfied in phases with simple thermodynamic structure, such as the droplet-scaling and chaotic pairs pictures. If instead nontrivial mixed-state pictures hold, the relations suggest that replica symmetry is broken as described by a Derrida-Ruelle cascade, with pure state weights distributed as a Poisson-Dirichlet process.

  11. Quantum fluctuations of the superconducting cosmic string

    NASA Technical Reports Server (NTRS)

    Zhang, Shoucheng

    1987-01-01

    Quantum fluctuations of the proposed superconducting string with Bose charge carriers are studied in terms of the vortices on the string world sheet. In the thermodynamical limit, it is found that they appear in the form of free vortices rather than as bound pairs. This fluctuation mode violates the topological conservation law on which superconductivity is based. However, this limit may not be reached. The critical size of the superconducting string is estimated as a function of the coupling constants involved.

  12. Condensate statistics in interacting and ideal dilute bose gases

    PubMed

    Kocharovsky; Kocharovsky; Scully

    2000-03-13

    We obtain analytical formulas for the statistics, in particular, for the characteristic function and all cumulants, of the Bose-Einstein condensate in dilute weakly interacting and ideal equilibrium gases in the canonical ensemble via the particle-number-conserving operator formalism of Girardeau and Arnowitt. We prove that the ground-state occupation statistics is not Gaussian even in the thermodynamic limit. We calculate the effect of Bogoliubov coupling on suppression of ground-state occupation fluctuations and show that they are governed by a pair-correlation, squeezing mechanism.

  13. Comparative study of the dissociation energies of Ni2 and Ni2(+)

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Partridge, Harry; Langhoff, Stephen R.

    1992-01-01

    Computations at the internally contracted averaged coupled-pair-functional level of theory yield a dissociation energy (Do) for Ni2(+) that is 0.17 eV larger than that of Ni2. This finding is consistent with the collision-induced dissociation experiments of Lian, Su, and Armentrout, but rules out the results from the resonant two-photon dissociation experiments of Lessen and Brucat, which predict that the Do value of Ni2(+) is about 1 eV larger than that of Ni2.

  14. Coupled tapering/uptapering of Thirring type soliton pair in nonlinear media

    NASA Astrophysics Data System (ADS)

    Prasad, Shraddha; Dutta, Manoj Kumar; Sarkar, Ram Krishna

    2018-03-01

    The paper investigates coupled tapering/uptapering of Thirring type soliton pair, employing Beam Propagation Method. It is seen that, the pair uptapers in presence of losses and tapers in presence of gain. When the first beam has gain and the second one has losses in the nonlinear medium, the second beam induces uptapering in the first beam, while, first beam induces tapering in the second beam. When the medium provides gain/losses to only one of the two beams, the beam undergoes tapering/uptapering and also induces tapering/uptapering to the other loss less beam; however, magnitude of tapering/uptapering are different.

  15. Magnetically Coupled Magnet-Spring Oscillators

    ERIC Educational Resources Information Center

    Donoso, G.; Ladera, C. L.; Martin, P.

    2010-01-01

    A system of two magnets hung from two vertical springs and oscillating in the hollows of a pair of coils connected in series is a new, interesting and useful example of coupled oscillators. The electromagnetically coupled oscillations of these oscillators are experimentally and theoretically studied. Its coupling is electromagnetic instead of…

  16. Space Shuttle critical function audit

    NASA Technical Reports Server (NTRS)

    Sacks, Ivan J.; Dipol, John; Su, Paul

    1990-01-01

    A large fault-tolerance model of the main propulsion system of the US space shuttle has been developed. This model is being used to identify single components and pairs of components that will cause loss of shuttle critical functions. In addition, this model is the basis for risk quantification of the shuttle. The process used to develop and analyze the model is digraph matrix analysis (DMA). The DMA modeling and analysis process is accessed via a graphics-based computer user interface. This interface provides coupled display of the integrated system schematics, the digraph models, the component database, and the results of the fault tolerance and risk analyses.

  17. Superconductivity switch from spin-singlet to -triplet pairing in a topological superconducting junction.

    PubMed

    Tao, Ze; Chen, F J; Zhou, L Y; Li, Bin; Tao, Y C; Wang, J

    2018-06-06

    The interedge coupling is the cardinal characteristic of the narrow quantum spin Hall (QSH) insulator, and thus could bring about exotic transport phenomena. Herein, we present a theoretical investigation of the spin-resolved Andreev reflection (AR) in a QSH insulator strip touching on two neighbouring ferromagnetic insulators and one s-wave superconductor. It is demonstrated that, due to the interplay of the interedge coupling and ferromagnetic configuration, there could be not only usual local ARs leading to the spin-singlet pairing with the incident electron and Andreev-reflected hole from different spin subbands, but also novel local ARs giving rise to the spin-triplet pairing from the same spin subband. However, only the latter exists in the absence of the interedge coupling, and therefore the two pairings in turn testify the helical spin texture of the edge states. By proper tuning of the band structures of the ferromagnetic layers, under the resonance bias voltage, the usual and novel local ARs of [Formula: see text] can be all exhibited, resulting in fully spin-polarized pure spin-singlet superconductivity and pure spin-triplet superconductivity, respectively, which suggests a superconductivity switch from spin-singlet to -triplet pairing by electrical control. The results can be experimentally confirmed by the tunneling conductance and the noise power.

  18. Superconductivity switch from spin-singlet to -triplet pairing in a topological superconducting junction

    NASA Astrophysics Data System (ADS)

    Tao, Ze; Chen, F. J.; Zhou, L. Y.; Li, Bin; Tao, Y. C.; Wang, J.

    2018-06-01

    The interedge coupling is the cardinal characteristic of the narrow quantum spin Hall (QSH) insulator, and thus could bring about exotic transport phenomena. Herein, we present a theoretical investigation of the spin-resolved Andreev reflection (AR) in a QSH insulator strip touching on two neighbouring ferromagnetic insulators and one s-wave superconductor. It is demonstrated that, due to the interplay of the interedge coupling and ferromagnetic configuration, there could be not only usual local ARs leading to the spin-singlet pairing with the incident electron and Andreev-reflected hole from different spin subbands, but also novel local ARs giving rise to the spin-triplet pairing from the same spin subband. However, only the latter exists in the absence of the interedge coupling, and therefore the two pairings in turn testify the helical spin texture of the edge states. By proper tuning of the band structures of the ferromagnetic layers, under the resonance bias voltage, the usual and novel local ARs of can be all exhibited, resulting in fully spin-polarized pure spin-singlet superconductivity and pure spin-triplet superconductivity, respectively, which suggests a superconductivity switch from spin-singlet to -triplet pairing by electrical control. The results can be experimentally confirmed by the tunneling conductance and the noise power.

  19. A Dyadic Analysis of Relationships and Health: Does Couple-Level Context Condition Partner Effects?

    PubMed Central

    Barr, Ashley B.; Simons, Ronald L.

    2014-01-01

    Adding to the growing literature explicating the links between romantic relationships and health, this study examined how both couple-level characteristics, particularly union type (e.g. dating, cohabiting, or marriage) and interracial pairing, and interpersonal characteristics (e.g. partner strain and support) predicted young adults’ physical and mental health. Using dyadic data from a sample of 249 young, primarily African American couples, we hypothesized and found support for the importance of couple-level context, partner behavior, and their interaction in predicting health. Interracial couples (all Black/non-Black pairings) reported worse health than monoracial Black couples. Union type, however, did not directly predict health but was a significant moderator of partner strain. That is, the negative association between partner strain and self-reported health was stronger for cohabiting and married couples versus their dating counterparts, suggesting that coresidence more so than marital status may be important for understanding partner effects on physical health. For psychological distress, however, partner support proved equally beneficial across union types. PMID:25090254

  20. A dyadic analysis of relationships and health: does couple-level context condition partner effects?

    PubMed

    Barr, Ashley B; Simons, Ronald L

    2014-08-01

    Adding to the growing literature explicating the links between romantic relationships and health, this study examined how both couple-level characteristics, particularly union type (e.g., dating, cohabiting, or marriage) and interracial pairing, and interpersonal characteristics (e.g., partner strain and support), predicted young adults' physical and mental health. Using dyadic data from a sample of 249 young, primarily Black couples, we hypothesized and found support for the importance of couple-level context, partner behavior, and their interaction in predicting health. Interracial couples (all Black/non-Black pairings) reported worse health than monoracial Black couples. Union type, however, did not directly predict health but was a significant moderator of partner strain. That is, the negative association between partner strain and self-reported health was stronger for cohabiting and married couples versus their dating counterparts, suggesting that coresidence, more so than marital status, may be important for understanding partner effects on physical health. For psychological distress, however, partner support proved equally beneficial across union types.

  1. Quantum Phases of Matter in Optical Lattices

    DTIC Science & Technology

    2015-06-30

    doi: 10.1103/PhysRevA.89.013625 Hyungwon Kim, David A. Huse. Ballistic Spreading of Entanglement in a Diffusive Nonintegrable System, Physical...Review B, (07 2013): 0. doi: 10.1103/PhysRevB.88.014206 Lin Dong, Lei Jiang, Han Pu. Fulde–Ferrell pairing instability in spin–orbit coupled Fermi...PhysRevA.87.051603 Kuei Sun, C. J. Bolech. Pair tunneling, phase separation, and dimensional crossover in imbalanced fermionic superfluids in a coupled

  2. Properties of isoscalar-pair condensates

    DOE PAGES

    Van Isacker, P.; Macchiavelli, A. O.; Fallon, P.; ...

    2016-08-17

    In this work, it is pointed out that the ground state of $n$ neutrons and n protons in a single-$j$ shell, interacting through an isoscalar ($T=0$) pairing force, is not paired, $J=0$, but rather spin aligned, $J=n$. This observation is explained in the context of a model of isoscalar $P(J=1)$ pairs, which is mapped onto a system of $p$ bosons, leading to an approximate analytic solution of the isoscalar-pairing limit in $jj$ coupling.

  3. Efficient genome editing by FACS enrichment of paired D10A Cas9 nickases coupled with fluorescent proteins.

    PubMed

    Gopalappa, Ramu; Song, Myungjae; Chandrasekaran, Arun Pandian; Das, Soumyadip; Haq, Saba; Koh, Hyun Chul; Ramakrishna, Suresh

    2018-05-31

    Targeted genome editing by clustered regularly interspaced short palindromic repeats (CRISPR-Cas9) raised concerns over off-target effects. The use of double-nicking strategy using paired Cas9 nickase has been developed to minimize off-target effects. However, it was reported that the efficiency of paired nickases were comparable or lower than that of either corresponding nuclease alone. Recently, we conducted a systematic comparison of the efficiencies of several paired Cas9 with their corresponding Cas9 nucleases and showed that paired D10A Cas9 nickases are sometimes more efficient than individual nucleases for gene disruption. However, sometimes the designed paired Cas9 nickases exhibited significantly lower mutation frequencies than nucleases, hampering the generation of cells containing paired Cas9 nickase-induced mutations. Here we implemented IRES peptide-conjugation of fluorescent protein to Cas9 nickase and subjected for fluorescence-activated cell sorting. The sorted cell populations are highly enriched with cells containing paired Cas9 nickase-induced mutations, by a factor of up to 40-fold as compared with the unsorted population. Furthermore, gene-disrupted single cell clones using paired nickases followed by FACS sorting strategy were generated highly efficiently, without compromising with its low off-target effects. We envision that our fluorescent protein coupled paired nickase-mediated gene disruption, facilitating efficient and highly specific genome editing in medical research.

  4. Combination of Wavefunction and Density Functional Approximations for Describing Electronic Correlation

    NASA Astrophysics Data System (ADS)

    Garza, Alejandro J.

    Perhaps the most important approximations to the electronic structure problem in quantum chemistry are those based on coupled cluster and density functional theories. Coupled cluster theory has been called the ``gold standard'' of quantum chemistry due to the high accuracy that it achieves for weakly correlated systems. Kohn-Sham density functionals based on semilocal approximations are, without a doubt, the most widely used methods in chemistry and material science because of their high accuracy/cost ratio. The root of the success of coupled cluster and density functionals is their ability to efficiently describe the dynamic part of the electron correlation. However, both traditional coupled cluster and density functional approximations may fail catastrophically when substantial static correlation is present. This severely limits the applicability of these methods to a plethora of important chemical and physical problems such as, e.g., the description of bond breaking, transition states, transition metal-, lanthanide- and actinide-containing compounds, and superconductivity. In an attempt to tackle this problem, nonstandard (single-reference) coupled cluster-based techniques that aim to describe static correlation have been recently developed: pair coupled cluster doubles (pCCD) and singlet-paired coupled cluster doubles (CCD0). The ability to describe static correlation in pCCD and CCD0 comes, however, at the expense of important amounts of dynamic correlation so that the high accuracy of standard coupled cluster becomes unattainable. Thus, the reliable and efficient description of static and dynamic correlation in a simultaneous manner remains an open problem for quantum chemistry and many-body theory in general. In this thesis, different ways to combine pCCD and CCD0 with density functionals in order to describe static and dynamic correlation simultaneously (and efficiently) are explored. The combination of wavefunction and density functional methods has a long history in quantum chemistry (practical implementations have appeared in the literature since the 1970s). However, this kind of techniques have not achieved widespread use due to problems such as double counting of correlation and the symmetry dilemma--the fact that wavefunction methods respect the symmetries of Hamiltonian, while modern functionals are designed to work with broken symmetry densities. Here, particular mathematical features of pCCD and CCD0 are exploited to avoid these problems in an efficient manner. The two resulting families of approximations, denoted as pCCD+DFT and CCD0+DFT, are shown to be able to describe static and dynamic correlation in standard benchmark calculations. Furthermore, it is also shown that CCD0+DFT lends itself to combination with correlation from the direct random phase approximation (dRPA). Inclusion of dRPA in the long-range via the technique of range-separation allows for the description of dispersion correlation, the remaining part of the correlation. Thus, when combined with the dRPA, CCD0+DFT can account for all three-types of electron correlation that are necessary to accurately describe molecular systems. Lastly, applications of CCD0+DFT to actinide chemistry are considered in this work. The accuracy of CCD0+DFT for predicting equilibrium geometries and vibrational frequencies of actinide molecules and ions is assessed and compared to that of well-established quantum chemical methods. For this purpose, the f0 actinyl series (UO2 2+, NpO 23+, PuO24+, the isoelectronic NUN, and Thorium (ThO, ThO2+) and Nobelium (NoO, NoO2) oxides are studied. It is shown that the CCD0+DFT description of these species agrees with available experimental data and is comparable with the results given by the highest-level calculations that are possible for such heavy compounds while being, at least, an order of magnitude lower in computational cost.

  5. Atomic-scale properties of Ni-based FCC ternary, and quaternary alloys

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

    Tamm, Artur; Aabloo, Alvo; Klintenberg, Mattias

    2015-08-26

    The aim of our study is to characterize some atomic-scale properties of Ni-based FCC multicomponent alloys. For this purpose, we use Monte Carlo method combined with density functional theory calculations to study short-range order (SRO), atomic displacements, electronic density of states, and magnetic moments in equimolar ternary NiCrCo, and quaternary NiCrCoFe alloys. The salient features for the ternary alloy are a negative SRO parameter between Ni Cr and a positive between Cr Cr pairs as well as a weakly magnetic state. For the quaternary alloy we predict negative SRO parameter for Ni Cr and Ni Fe pairs and positive formore » Cr Cr and Fe Fe pairs. Atomic displacements for both ternary and quaternary alloys are negligible. In contrast to the ternary, the quaternary alloy shows a complex magnetic structure. The electronic structure of the ternary and quaternary alloys shows differences near the Fermi energy between a random solid solution and the predicted structure with SRO. Despite that, the calculated EXAFS spectra does not show enough contrast to discriminate between random and ordered structures. Finally, the predicted SRO has an impact on point-defect energetics, electron phonon coupling and thermodynamic functions and thus, SRO should not be neglected when studying properties of these two alloys.« less

  6. Constraints on black hole remnants

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

    Giddings, S.B.

    1994-01-15

    One possible fate of information lost to black holes is its preservation in black hole remnants. It is argued that a type of effective field theory describes such remnants (generically referred to as informons). The general structure of such a theory is investigated and the infinite pair production problem is revisited. A toy model for remnants clarifies some of the basic issues; in particular, infinite remnant production is not suppressed simply by the large internal volumes as proposed in cornucopion scenarios. Criteria for avoiding infinite production are stated in terms of couplings in the effective theory. Such instabilities remain amore » problem barring what would be described in that theory as a strong coupling conspiracy. The relation to Euclidean calculations of cornucopion production is sketched, and potential flaws in that analysis are outlined. However, it is quite plausible that pair production of ordinary black holes (e.g., Reissner-Noerdstrom or others) is suppressed due to strong effective couplings. It also remains an open possibility that a microsopic dynamics can be found yielding an appropriate strongly coupled effective theory of neutral informons without infinite pair production.« less

  7. Altered minor-groove hydrogen bonds in DNA block transcription elongation by T7 RNA polymerase.

    PubMed

    Tanasova, Marina; Goeldi, Silvan; Meyer, Fabian; Hanawalt, Philip C; Spivak, Graciela; Sturla, Shana J

    2015-05-26

    DNA transcription depends upon the highly efficient and selective function of RNA polymerases (RNAPs). Modifications in the template DNA can impact the progression of RNA synthesis, and a number of DNA adducts, as well as abasic sites, arrest or stall transcription. Nonetheless, data are needed to understand why certain modifications to the structure of DNA bases stall RNA polymerases while others are efficiently bypassed. In this study, we evaluate the impact that alterations in dNTP/rNTP base-pair geometry have on transcription. T7 RNA polymerase was used to study transcription over modified purines and pyrimidines with altered H-bonding capacities. The results suggest that introducing wobble base-pairs into the DNA:RNA heteroduplex interferes with transcriptional elongation and stalls RNA polymerase. However, transcriptional stalling is not observed if mismatched base-pairs do not H-bond. Together, these studies show that RNAP is able to discriminate mismatches resulting in wobble base-pairs, and suggest that, in cases of modifications with minor steric impact, DNA:RNA heteroduplex geometry could serve as a controlling factor for initiating transcription-coupled DNA repair. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Anatomical connectivity influences both intra- and inter-brain synchronizations.

    PubMed

    Dumas, Guillaume; Chavez, Mario; Nadel, Jacqueline; Martinerie, Jacques

    2012-01-01

    Recent development in diffusion spectrum brain imaging combined to functional simulation has the potential to further our understanding of how structure and dynamics are intertwined in the human brain. At the intra-individual scale, neurocomputational models have already started to uncover how the human connectome constrains the coordination of brain activity across distributed brain regions. In parallel, at the inter-individual scale, nascent social neuroscience provides a new dynamical vista of the coupling between two embodied cognitive agents. Using EEG hyperscanning to record simultaneously the brain activities of subjects during their ongoing interaction, we have previously demonstrated that behavioral synchrony correlates with the emergence of inter-brain synchronization. However, the functional meaning of such synchronization remains to be specified. Here, we use a biophysical model to quantify to what extent inter-brain synchronizations are related to the anatomical and functional similarity of the two brains in interaction. Pairs of interacting brains were numerically simulated and compared to real data. Results show a potential dynamical property of the human connectome to facilitate inter-individual synchronizations and thus may partly account for our propensity to generate dynamical couplings with others.

  9. Structure of Voltage-gated Two-pore Channel TPC1 from Arabidopsis thaliana

    PubMed Central

    Guo, Jiangtao; Zeng, Weizhong; Chen, Qingfeng; Lee, Changkeun; Chen, Liping; Yang, Yi; Cang, Chunlei; Ren, Dejian; Jiang, Youxing

    2015-01-01

    Two-pore channels (TPCs) contain two copies of a Shaker-like six-transmembrane (6-TM) domain in each subunit and are ubiquitously expressed in both animals and plants as organellar cation channels. Here, we present the first crystal structure of a vacuolar two-pore channel from Arabidopsis thaliana, AtTPC1, which functions as a homodimer. AtTPC1 activation requires both voltage and cytosolic Ca2+. Ca2+ binding to the cytosolic EF-hand domain triggers conformational changes coupled to the pair of pore-lining inner helices (IS6 helices) from the first 6-TM domains, whereas membrane potential only activates the second voltage-sensing domain (VSD2) whose conformational changes are coupled to the pair of inner helices (IIS6 helices) from the second 6-TM domains. Luminal Ca2+ or Ba2+ can modulate voltage activation by stabilizing VSD2 in the resting state and shifts voltage activation towards more positive potentials. Our Ba2+ bound AtTPC1 structure reveals a voltage sensor in the resting state, providing hitherto unseen structural insight into the general voltage-gating mechanism among voltage-gated channels. PMID:26689363

  10. Designing allostery-inspired response in mechanical networks

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

    Rocks, Jason W.; Pashine, Nidhi; Bischofberger, Irmgard

    Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are then able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ~1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individualmore » response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks.« less

  11. Designing allostery-inspired response in mechanical networks

    DOE PAGES

    Rocks, Jason W.; Pashine, Nidhi; Bischofberger, Irmgard; ...

    2017-02-21

    Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are then able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ~1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individualmore » response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks.« less

  12. Designing allostery-inspired response in mechanical networks

    PubMed Central

    Rocks, Jason W.; Pashine, Nidhi; Bischofberger, Irmgard; Goodrich, Carl P.; Liu, Andrea J.; Nagel, Sidney R.

    2017-01-01

    Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ∼1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individual response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks. PMID:28223534

  13. Designing allostery-inspired response in mechanical networks.

    PubMed

    Rocks, Jason W; Pashine, Nidhi; Bischofberger, Irmgard; Goodrich, Carl P; Liu, Andrea J; Nagel, Sidney R

    2017-03-07

    Recent advances in designing metamaterials have demonstrated that global mechanical properties of disordered spring networks can be tuned by selectively modifying only a small subset of bonds. Here, using a computationally efficient approach, we extend this idea to tune more general properties of networks. With nearly complete success, we are able to produce a strain between any two target nodes in a network in response to an applied source strain on any other pair of nodes by removing only ∼1% of the bonds. We are also able to control multiple pairs of target nodes, each with a different individual response, from a single source, and to tune multiple independent source/target responses simultaneously into a network. We have fabricated physical networks in macroscopic 2D and 3D systems that exhibit these responses. This work is inspired by the long-range coupled conformational changes that constitute allosteric function in proteins. The fact that allostery is a common means for regulation in biological molecules suggests that it is a relatively easy property to develop through evolution. In analogy, our results show that long-range coupled mechanical responses are similarly easy to achieve in disordered networks.

  14. Origin of intrinsic Josephson coupling in the cuprates and its relation to order parameter symmetry: An incoherent hopping model

    NASA Astrophysics Data System (ADS)

    Radtke, R. J.; Levin, K.

    1995-02-01

    Experiments on the cuprate superconductors demonstrate that these materials may be viewed as a stack of Josephson junctions along the direction normal to the CuO 2 planes (the c-axis). In this paper, we present a model which describes this intrinsic Josephson coupling in terms of incherent quasiparticle hopping along the c-axis arising from wave-function overlap, impurity-assisted hopping, and boson-assised hopping. We use this model to compute the magnitude and temperature T dependence of the resulting Josephson critical current jc( T) for s- and d-wave superconductors. Contrary to other approaches, d-wave pairing in this model is compatible with an intrinsic Josephson effect at all hole concentrations and leads to jc( T) αT at low T. By parameterizing our theory with c-axis resistivity data from YBa 2Cu 3O 7-δ (YBCO), we estimate jc( T) for optimally doped and underdoped members of this family. jc( T) can be measured either directly or indirectly through microwave penetration depth experiments, and current measurements on Bi 2Sr 2CaCu 2O 8 and La 2- xSr xCuO 4 are found to be consistent with s-wave pairing and the dominance of assisted hopping processes. The situation in YBCO is still unclear, but our estimates suggest that further experiments on this compound would be of great help in elucidating the validity of our model in general and the pairing symmetry in particular.

  15. Analytic energy derivatives for the calculation of the first-order molecular properties using the domain-based local pair-natural orbital coupled-cluster theory

    NASA Astrophysics Data System (ADS)

    Datta, Dipayan; Kossmann, Simone; Neese, Frank

    2016-09-01

    The domain-based local pair-natural orbital coupled-cluster (DLPNO-CC) theory has recently emerged as an efficient and powerful quantum-chemical method for the calculation of energies of molecules comprised of several hundred atoms. It has been demonstrated that the DLPNO-CC approach attains the accuracy of a standard canonical coupled-cluster calculation to about 99.9% of the basis set correlation energy while realizing linear scaling of the computational cost with respect to system size. This is achieved by combining (a) localized occupied orbitals, (b) large virtual orbital correlation domains spanned by the projected atomic orbitals (PAOs), and (c) compaction of the virtual space through a truncated pair natural orbital (PNO) basis. In this paper, we report on the implementation of an analytic scheme for the calculation of the first derivatives of the DLPNO-CC energy for basis set independent perturbations within the singles and doubles approximation (DLPNO-CCSD) for closed-shell molecules. Perturbation-independent one-particle density matrices have been implemented in order to account for the response of the CC wave function to the external perturbation. Orbital-relaxation effects due to external perturbation are not taken into account in the current implementation. We investigate in detail the dependence of the computed first-order electrical properties (e.g., dipole moment) on the three major truncation parameters used in a DLPNO-CC calculation, namely, the natural orbital occupation number cutoff used for the construction of the PNOs, the weak electron-pair cutoff, and the domain size cutoff. No additional truncation parameter has been introduced for property calculation. We present benchmark calculations on dipole moments for a set of 10 molecules consisting of 20-40 atoms. We demonstrate that 98%-99% accuracy relative to the canonical CCSD results can be consistently achieved in these calculations. However, this comes with the price of tightening the threshold for the natural orbital occupation number cutoff by an order of magnitude compared to the DLPNO-CCSD energy calculations.

  16. High heralding-efficiency of near-IR fiber coupled photon pairs for quantum technologies

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

    Dixon, P. Ben; Murphy, Ryan; Rosenberg, Danna

    We report on the development and use of a high heralding-efficiency, single-mode-fiber coupled telecom-band source of entangled photons for quantum technology applications. The source development efforts consisted of theoretical and experimental efforts and we demonstrated a correlated-mode coupling efficiency of 97% 2%, the highest efficiency yet achieved for this type of system. We then incorporated these beneficial source development techniques in a Sagnac configured telecom-band entangled photon source that generates photon pairs entangled in both time/energy and polarization degrees of freedom. We made use of these highly desirable entangled states to investigate several promising quantum technologies.

  17. Equalizer tap length requirement for mode group delay-compensated fiber link with weakly random mode coupling.

    PubMed

    Bai, Neng; Li, Guifang

    2014-02-24

    The equalizer tap length requirement is investigated analytically and numerically for differential modal group delay (DMGD) compensated fiber link with weakly random mode coupling. Each span of the DMGD compensated link comprises multiple pairs of fibers which have opposite signs of DMGD. The result reveals that under weak random mode coupling, the required tap length of the equalizer is proportional to modal group delay of a single DMGD compensated pair, instead of the total modal group delay (MGD) of the entire link. By using small DMGD compensation step sizes, the required tap length (RTL) can be potentially reduced by 2 orders of magnitude.

  18. Electrical coupling between A17 cells enhances reciprocal inhibitory feedback to rod bipolar cells.

    PubMed

    Elgueta, Claudio; Leroy, Felix; Vielma, Alex H; Schmachtenberg, Oliver; Palacios, Adrian G

    2018-02-15

    A17 amacrine cells are an important part of the scotopic pathway. Their synaptic varicosities receive glutamatergic inputs from rod bipolar cells (RBC) and release GABA onto the same RBC terminal, forming a reciprocal feedback that shapes RBC depolarization. Here, using patch-clamp recordings, we characterized electrical coupling between A17 cells of the rat retina and report the presence of strongly interconnected and non-coupled A17 cells. In coupled A17 cells, evoked currents preferentially flow out of the cell through GJs and cross-synchronization of presynaptic signals in a pair of A17 cells is correlated to their coupling degree. Moreover, we demonstrate that stimulation of one A17 cell can induce electrical and calcium transients in neighboring A17 cells, thus confirming a functional flow of information through electrical synapses in the A17 coupled network. Finally, blocking GJs caused a strong decrease in the amplitude of the inhibitory feedback onto RBCs. We therefore propose that electrical coupling between A17 cells enhances feedback onto RBCs by synchronizing and facilitating GABA release from inhibitory varicosities surrounding each RBC axon terminal. GJs between A17 cells are therefore critical in shaping the visual flow through the scotopic pathway.

  19. Rogue-pair and dark-bright-rogue waves of the coupled nonlinear Schrödinger equations from inhomogeneous femtosecond optical fibers.

    PubMed

    Yomba, Emmanuel; Zakeri, Gholam-Ali

    2016-08-01

    The coupled inhomogeneous Schrödinger equations with a wide range of applications describing a field of pluses with the right and the left polarizations that take into account cross-phase modulations, stimulated Ramani scattering, and absorption effects are investigated. A combination of several different approaches is used in a novel way to obtain the explicit expressions for the rogue-pair and dark-bright-rogue waves. We study the dynamics of these structurally stable rogues and analyze the effects of a parameter that controls the region of stability that intrinsically connects the cross-phase modulation and other Kerr nonlinearity factors. The effects of the right and left polarizations on the shape of the rogue-pair and other solitary rogue waves are graphically analyzed. These rogue-pair waves are studied on periodic and non-periodic settings. We observe that rogue-pair wave from the right and left polarizations has a similar structure while the dark-bright-rogue waves have quite different intensity profiles.

  20. Treatment of pairing correlations based on the equations of motion for zero-coupled pair operators

    NASA Astrophysics Data System (ADS)

    Andreozzi, F.; Covello, A.; Gargano, A.; Ye, Liu Jian; Porrino, A.

    1985-07-01

    The pairing problem is treated by means of the equations of motion for zero-coupled pair operators. Exact equations for the seniority-v states of N particles are derived. These equations can be solved by a step-by-step procedure which consists of progressively adding pairs of particles to a core. The theory can be applied at several levels of approximation depending on the number of core states which are taken into account. Some numerical applications to the treatment of v=0, v=1, and v=2 states in the Ni isotopes are performed. The accuracy of various approximations is tested by comparison with exact results. For the seniority-one and seniority-two problems it turns out that the results obtained from the first-order theory are very accurate, while those of higher order calculations are practically exact. Concerning the seniority-zero problem, a fifth-order calculation reproduces quite well the three lowest states.

  1. Supercurrent in ferromagnetic Josephson junctions with heavy metal interlayers

    NASA Astrophysics Data System (ADS)

    Satchell, Nathan; Birge, Norman O.

    2018-06-01

    The length scale over which supercurrent from conventional BCS, s -wave superconductors (S ) can penetrate an adjacent ferromagnetic (F ) layer depends on the ability to convert singlet Cooper pairs into triplet Cooper pairs. Spin-aligned triplet Cooper pairs are not dephased by the ferromagnetic exchange interaction and can thus penetrate an F layer over much longer distances than singlet Cooper pairs. These triplet Cooper pairs carry a dissipationless spin current and are the fundamental building block for the fledgling field of superspintronics. Singlet-triplet conversion by inhomogeneous magnetism is well established. Here, we describe an attempt to use spin-orbit coupling as an alternative mechanism to mediate singlet-triplet conversion in S-F-S Josephson junctions. We report that the addition of thin Pt spin-orbit-coupling layers in our Josephson junctions significantly increases supercurrent transmission, however the decay length of the supercurrent is not found to increase. We attribute the increased supercurrent transmission to Pt acting as a buffer layer to improve the growth of the Co F layer.

  2. The preBötzinger complex as a hub for network activity along the ventral respiratory column in the neonate rat.

    PubMed

    Gourévitch, Boris; Mellen, Nicholas

    2014-09-01

    In vertebrates, respiratory control is ascribed to heterogeneous respiration-modulated neurons along the Ventral Respiratory Column (VRC) in medulla, which includes the preBötzinger Complex (preBötC), the putative respiratory rhythm generator. Here, the functional anatomy of the VRC was characterized via optical recordings in the sagittaly sectioned neonate rat hindbrain, at sampling rates permitting coupling estimation between neuron pairs, so that each neuron was described using unitary, neuron-system, and coupling attributes. Structured coupling relations in local networks, significantly oriented coupling in the peri-inspiratory interval detected in pooled data, and significant correlations between firing rate and expiratory duration in subsets of neurons revealed network regulation at multiple timescales. Spatially averaged neuronal attributes, including coupling vectors, revealed a sharp boundary at the rostral margin of the preBötC, as well as other functional anatomical features congruent with identified structures, including the parafacial respiratory group and the nucleus ambiguus. Cluster analysis of attributes identified two spatially compact, homogenous groups: the first overlapped with the preBötC, and was characterized by strong respiratory modulation and dense bidirectional coupling with itself and other groups, consistent with a central role for the preBötC in respiratory control; the second lay between preBötC and the facial nucleus, and was characterized by weak respiratory modulation and weak coupling with other respiratory neurons, which is congruent with cardiovascular regulatory networks that are found in this region. Other groups identified using cluster analysis suggested that networks along VRC regulated expiratory duration, and the transition to and from inspiration, but these groups were heterogeneous and anatomically dispersed. Thus, by recording local networks in parallel, this study found evidence for respiratory regulation at multiple timescales along the VRC, as well as a role for the preBötC in the integration of functionally disparate respiratory neurons. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Probing the Higgs self coupling via single Higgs production at the LHC

    DOE PAGES

    Degrassi, G.; Giardino, P. P.; Maltoni, F.; ...

    2016-12-16

    Here, we propose a method to determine the trilinear Higgs self coupling that is alternative to the direct measurement of Higgs pair production total cross sections and differential distributions. Furthermore, the method relies on the effects that electroweak loops featuring an anomalous trilinear coupling would imprint on single Higgs production at the LHC. We first calculate these contributions to all the phenomenologically relevant Higgs production (ggF, VBF, WH, ZH, tmore » $$\\bar{t}$$ ) and decay (γγ,WW*/ZZ*→ 4f, b$$\\bar{b}$$,ττ) modes at the LHC and then estimate the sensitivity to the trilinear coupling via a one-parameter fit to the single Higgs measurements at the LHC 8 TeV. We also found that the bounds on the self coupling are already competitive with those from Higgs pair production and will be further improved in the current and next LHC runs.« less

  4. Acetylcholine receptor gating at extracellular transmembrane domain interface: the "pre-M1" linker.

    PubMed

    Purohit, Prasad; Auerbach, Anthony

    2007-12-01

    Charged residues in the beta10-M1 linker region ("pre-M1") are important in the expression and function of neuromuscular acetylcholine receptors (AChRs). The perturbation of a salt bridge between pre-M1 residue R209 and loop 2 residue E45 has been proposed as being a principle event in the AChR gating conformational "wave." We examined the effects of mutations to all five residues in pre-M1 (positions M207-P211) plus E45 in loop 2 in the mouse alpha(1)-subunit. M207, Q208, and P211 mutants caused small (approximately threefold) changes in the gating equilibrium constant (K(eq)), but the changes for R209, L210, and E45 were larger. Of 19 different side chain substitutions at R209 on the wild-type background, only Q, K, and H generated functional channels, with the largest change in K(eq) (67-fold) from R209Q. Various R209 mutants were functional on different E45 backgrounds: H, Q, and K (E45A), H, A, N, and Q (E45R), and K, A, and N (E45L). Phi values for R209 (on the E45A background), L210, and E45 were 0.74, 0.35, and 0.80, respectively. Phi values for R209 on the wt and three other backgrounds could not be estimated because of scatter. The average coupling energy between 209/45 side chains (six different pairs) was only -0.33 kcal/mol (for both alpha subunits, combined). Pre-M1 residues are important for expression of functional channels and participate in gating, but the relatively modest changes in closed- vs. open-state energy caused mutations, the weak coupling energy between these residues and the functional activity of several unmatched-charge pairs are not consistent with the perturbation of a salt bridge between R209 and E45 playing the principle role in gating.

  5. Soliton creation, propagation, and annihilation in aeromechanical arrays of one-way coupled bistable elements

    NASA Astrophysics Data System (ADS)

    Rosenberger, Tessa; Lindner, John F.

    We study the dynamics of mechanical arrays of bistable elements coupled one-way by wind. Unlike earlier hydromechanical unidirectional arrays, our aeromechanical one-way arrays are simpler, easier to study, and exhibit a broader range of phenomena. Soliton-like waves propagate in one direction at speeds proportional to wind speeds. Periodic boundaries enable solitons to annihilate in pairs in even arrays where adjacent elements are attracted to opposite stable states. Solitons propagate indefinitely in odd arrays where pairing is frustrated. Large noise spontaneously creates soliton- antisoliton pairs, as predicted by prior computer simulations. Soliton annihilation times increase quadratically with initial separations, as expected for random walk models of soliton collisions.

  6. Analytic Results for e+e- --> tt-bar and gammagamma --> tt-bar Observables near the Threshold up to the Next-to-Next-to-Leading Order of NRQCD

    NASA Astrophysics Data System (ADS)

    Penin, A. A.; Pivovarov, A. A.

    2001-02-01

    We present an analytical description of top-antitop pair production near the threshold in $e^+e^-$ annihilation and $\\g\\g$ collisions. A set of basic observables considered includes the total cross sections, forward-backward asymmetry and top quark polarization. The threshold effects relevant for the basic observables are described by three universal functions related to S wave production, P wave production and S-P interference. These functions are computed analytically up to the next-to-next-to-leading order of NRQCD. The total $e^+e^-\\to t\\bar t$ cross section near the threshold is obtained in the next-to-next-to-leading order in the closed form including the contribution due to the axial coupling of top quark and mediated by the Z-boson. The effects of the running of the strong coupling constant and of the finite top quark width are taken into account analytically for the P wave production and S-P wave interference.

  7. A molecular orbital study of the energy spectrum, exchange interaction and gate crosstalk of a four-quantum-dot system

    NASA Astrophysics Data System (ADS)

    Yang, Xu-Chen; Wang, Xin

    The manipulation of coupled quantum dot devices is crucial to scalable, fault-tolerant quantum computation. We present a theoretical study of a four-electron four-quantum-dot system based on molecular orbital methods, which depicts a pair of singlet-triplet (S-T) qubits. We find that while the two S-T qubits are coupled by the capacitive interaction when they are sufficiently far away, the admixture of wave functions undergoes a substantial change as the two S-T qubits get closer. We find that in certain parameter regime the exchange interaction may only be defined in the sense of an effective one when the computational basis states no longer dominate the eigenstates. We further discuss the gate crosstalk as a consequence of this wave function mixing. This work was supported by the Research Grants Council of the Hong Kong Special Administrative Region, China (No. CityU 21300116) and the National Natural Science Foundation of China (No. 11604277).

  8. Surface Inhomogeneities of the White Dwarf in the Binary EUVE J2013+400

    NASA Astrophysics Data System (ADS)

    Vennes, Stephane

    We propose to study the white dwarf in the binary EUVE J2013+400. The object is paired with a dMe star and new extreme ultraviolet (EUV) observations will offer critical insights into the properties of the white dwarf. The binary behaves, in every other aspects, like its siblings EUVE J0720-317 and EUVE J1016-053 and new EUV observations will help establish their class properties; in particular, EUV photometric variations in 0720-317 and 1016-053 over a period of 11 hours and 57 minutes, respectively, are indicative of surface abundance inhomogeneities coupled with the white dwarfs rotation period. These variations and their large photospheric helium abundance are best explained by a diffusion-accretion model in which time-variable accretion and possible coupling to magnetic poles contribute to abundance variations across the surface and possibly as a function of depth. EUV spectroscopy will also enable a study of the helium abundance as a function of depth and a detailed comparison with theoretical diffusion profile.

  9. Diffusion Monte Carlo study of strongly interacting two-dimensional Fermi gases

    DOE PAGES

    Galea, Alexander; Dawkins, Hillary; Gandolfi, Stefano; ...

    2016-02-01

    Ultracold atomic Fermi gases have been a popular topic of research, with attention being paid recently to two-dimensional (2D) gases. In this work, we perform T=0 ab initio diffusion Monte Carlo calculations for a strongly interacting two-component Fermi gas confined to two dimensions. We first go over finite-size systems and the connection to the thermodynamic limit. After that, we illustrate pertinent 2D scattering physics and properties of the wave function. We then show energy results for the strong-coupling crossover, in between the Bose-Einstein condensation (BEC) and Bardeen-Cooper-Schrieffer (BCS) regimes. Our energy results for the BEC-BCS crossover are parametrized to producemore » an equation of state, which is used to determine Tan's contact. We carry out a detailed comparison with other microscopic results. Lastly, we calculate the pairing gap for a range of interaction strengths in the strong coupling regime, following from variationally optimized many-body wave functions.« less

  10. Determination of the top-quark pole mass and strong coupling constant from the t t-bar production cross section in pp collisions at $$\\sqrt{s}$$ = 7 TeV

    DOE PAGES

    Chatrchyan, Serguei

    2014-08-21

    The inclusive cross section for top-quark pair production measured by the CMS experiment in proton-proton collisions at a center-of-mass energy of 7 TeV is compared to the QCD prediction at next-to-next-to-leading order with various parton distribution functions to determine the top-quark pole mass,more » $$m_t^{pole}$$, or the strong coupling constant, $$\\alpha_S$$. With the parton distribution function set NNPDF2.3, a pole mass of 176.7$$^{+3.0}_{-2.8}$$ GeV is obtained when constraining $$\\alpha_S$$ at the scale of the Z boson mass, $$m_Z$$, to the current world average. Alternatively, by constraining $$m_t^{pole}$$ to the latest average from direct mass measurements, a value of $$\\alpha_S(m_Z)$$ = 0.1151$$^{+0.0028}_{-0.0027}$$ is extracted. This is the first determination of $$\\alpha_S$$ using events from top-quark production.« less

  11. Effects of magnetic and nonmagnetic impurities on the spin susceptibility of a noncentrosymmetrical superconductor: Application to CePt3Si

    NASA Astrophysics Data System (ADS)

    Yavari, H.; Mokhtari, M.; Tamaddonpour, M.

    2013-10-01

    The combined effect of nonmagnetic and magnetic impurities on the spin susceptibility of a noncentrosymmetrical superconductor by considering a Cooper pairing model with a two-component order parameter composed of spin-singlet and spin-triplet pairing components is investigated. For clean superconductor CePt3Si, the low-temperature dependence (T →0) of spin susceptibility is linear which suggests that the gap function has line nodes, consistent with our gap model. We will show that in the presence of magnetic impurities the susceptibility does not vanish even in the absence of spin orbit coupling and in the region where the energy gap still is finite, and in the low concentration of magnetic impurities the spin susceptibility at zero temperature is proportional to impurity concentration.

  12. Topological winding properties of spin edge states in the Kane-Mele graphene model

    NASA Astrophysics Data System (ADS)

    Wang, Zhigang; Hao, Ningning; Zhang, Ping

    2009-09-01

    We study the spin edge states in the quantum spin-Hall (QSH) effect on a single-atomic layer graphene-ribbon system with both intrinsic and Rashba spin-orbit couplings. The Harper equation for solving the energies of the spin edge states is derived. The results show that in the QSH phase, there are always two pairs of gapless spin-filtered edge states in the bulk energy gap, corresponding to two pairs of zero points of the Bloch function on the complex-energy Riemann surface (RS). The topological aspect of the QSH phase can be distinguished by the difference of the winding numbers of the spin edge states with different polarized directions cross the holes of the RS, which is equivalent to the Z2 topological invariance proposed by Kane and Mele [Phys. Rev. Lett. 95, 146802 (2005)].

  13. A global view on the Higgs self-coupling at lepton colliders

    DOE PAGES

    Di Vita, Stefano; Durieux, Gauthier; Grojean, Christophe; ...

    2018-02-28

    We perform a global effective-field-theory analysis to assess the precision on the determination of the Higgs trilinear self-coupling at future lepton colliders. Two main scenarios are considered, depending on whether the center-of-mass energy of the colliders is sufficient or not to access Higgs pair production processes. Low-energy machines allow for ~40% precision on the extraction of the Higgs trilinear coupling through the exploitation of next-to-leading-order effects in single Higgs measurements, provided that runs at both 240/250 GeV and 350 GeV are available with luminosities in the few attobarns range. A global fit, including possible deviations in other SM couplings, ismore » essential in this case to obtain a robust determination of the Higgs self-coupling. High-energy machines can easily achieve a ~20% precision through Higgs pair production processes. In this case, the impact of additional coupling modifications is milder, although not completely negligible.« less

  14. A global view on the Higgs self-coupling at lepton colliders

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

    Di Vita, Stefano; Durieux, Gauthier; Grojean, Christophe

    We perform a global effective-field-theory analysis to assess the precision on the determination of the Higgs trilinear self-coupling at future lepton colliders. Two main scenarios are considered, depending on whether the center-of-mass energy of the colliders is sufficient or not to access Higgs pair production processes. Low-energy machines allow for ~40% precision on the extraction of the Higgs trilinear coupling through the exploitation of next-to-leading-order effects in single Higgs measurements, provided that runs at both 240/250 GeV and 350 GeV are available with luminosities in the few attobarns range. A global fit, including possible deviations in other SM couplings, ismore » essential in this case to obtain a robust determination of the Higgs self-coupling. High-energy machines can easily achieve a ~20% precision through Higgs pair production processes. In this case, the impact of additional coupling modifications is milder, although not completely negligible.« less

  15. Modulational instability, beak-shaped rogue waves, multi-dark-dark solitons and dynamics in pair-transition-coupled nonlinear Schrödinger equations.

    PubMed

    Zhang, Guoqiang; Yan, Zhenya; Wen, Xiao-Yong

    2017-07-01

    The integrable coupled nonlinear Schrödinger equations with four-wave mixing are investigated. We first explore the conditions for modulational instability of continuous waves of this system. Secondly, based on the generalized N -fold Darboux transformation (DT), beak-shaped higher-order rogue waves (RWs) and beak-shaped higher-order rogue wave pairs are derived for the coupled model with attractive interaction in terms of simple determinants. Moreover, we derive the simple multi-dark-dark and kink-shaped multi-dark-dark solitons for the coupled model with repulsive interaction through the generalizing DT. We explore their dynamics and classifications by different kinds of spatial-temporal distribution structures including triangular, pentagonal, 'claw-like' and heptagonal patterns. Finally, we perform the numerical simulations to predict that some dark solitons and RWs are stable enough to develop within a short time. The results would enrich our understanding on nonlinear excitations in many coupled nonlinear wave systems with transition coupling effects.

  16. How nature designs light-harvesting antenna systems: design principles and functional realization in chlorophototrophic prokaryotes

    NASA Astrophysics Data System (ADS)

    Bryant, Donald A.; Canniffe, Daniel P.

    2018-02-01

    Chlorophyll-based phototrophs, or chlorophototrophs, convert light energy into stored chemical potential energy using two types of photochemical reaction center (RC), denoted type-1 and type-2. After excitation with light, a so-called special pair of chlorophylls in the RC is oxidized, and an acceptor is reduced. To ensure that RCs function at maximal rates in diffuse and variable light conditions, chlorophototrophs have independently evolved diverse light-harvesting antenna systems to rapidly and efficiently transfer that energy to the RCs. Energy transfer between weakly coupled chromophores is generally believed to proceed by resonance energy transfer, a dipole-induced-dipole process that was initially described theoretically by Förster. Nature principally optimizes three parameters in antenna systems: the distance separating the donor and acceptor chromophores, the relative orientations of those chromophores, and the spectral overlap between the donor and the acceptor chromophores. However, there are other important biological parameters that nature has optimized, and some common themes emerge from comparisons of different antenna systems. This tutorial considers structural and functional characteristics of three fundamentally different light-harvesting antenna systems of chlorophotrophic bacteria: phycobilisomes of cyanobacteria, the light-harvesting complexes (LH1 and LH2) of purple bacteria, and chlorosomes of green bacteria. Phycobilisomes are generally considered to represent an antenna system in which the chromophores are weakly coupled, while the strongly coupled bacteriochlorophyll molecules in LH1 and LH2 are strongly coupled and are better described by exciton theory. Chlorosomes can contain up to 250 000 bacteriochlorophyll molecules, which are very strongly coupled and form supramolecular, nanotubular arrays. The general and specific principles that have been optimized by natural selection during the evolution of these diverse light-harvesting antenna systems are discussed.

  17. Catalytic Dehydrogenative Coupling of Hydrosilanes with Alcohols for the Production of Hydrogen On-demand: Application of a Silane/Alcohol Pair as a Liquid Organic Hydrogen Carrier.

    PubMed

    Ventura-Espinosa, David; Carretero-Cerdán, Alba; Baya, Miguel; García, Hermenegildo; Mata, Jose A

    2017-08-10

    The compound [Ru(p-cym)(Cl) 2 (NHC)] is an effective catalyst for the room-temperature coupling of silanes and alcohols with the concomitant formation of molecular hydrogen. High catalyst activity is observed for a variety of substrates affording quantitative yields in minutes at room temperature and with a catalyst loading as low as 0.1 mol %. The coupling reaction is thermodynamically and, in the presence of a Ru complex, kinetically favourable and allows rapid molecular hydrogen generation on-demand at room temperature, under air, and without any additive. The pair silane/alcohol is a potential liquid organic hydrogen carrier (LOHC) for energy storage over long periods in a safe and secure way. Silanes and alcohols are non-toxic compounds and do not require special handling precautions such as high pressure or an inert atmosphere. These properties enhance the practical applications of the pair silane/alcohol as a good LOHC in the automotive industry. The variety and availability of silanes and alcohols permits a pair combination that fulfils the requirements for developing an efficient LOHC. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Theoretical Study of the H2-ML(+) Binding Energies

    NASA Technical Reports Server (NTRS)

    Maitre, Philippe; Bauschlicher, Charles W., Jr.

    1993-01-01

    The cooperative ligand effects are studied in MLH2(+) and the results are compared to the recent experiments of Kemper et al. The bonding in these compounds is principally electrostatic in origin; however, ligand to metal and metal to ligand donations are important, especially for H2. We show that differences arise among the vanadium, cobalt, and copper complexes which are due to 3d donation to H2. Electron correlation is required to describe the dative interaction, and we find that second order Moller-Plesset perturbation theory (MP2) yields a good description of these systems compared with higher levels of correlation (such as the modified coupled pair functional and coupled cluster approaches) and experiment. However, obtaining quantitative results requires higher levels of theory than MP2.

  19. Design of magnetic coordination complexes for quantum computing.

    PubMed

    Aromí, Guillem; Aguilà, David; Gamez, Patrick; Luis, Fernando; Roubeau, Olivier

    2012-01-21

    A very exciting prospect in coordination chemistry is to manipulate spins within magnetic complexes for the realization of quantum logic operations. An introduction to the requirements for a paramagnetic molecule to act as a 2-qubit quantum gate is provided in this tutorial review. We propose synthetic methods aimed at accessing such type of functional molecules, based on ligand design and inorganic synthesis. Two strategies are presented: (i) the first consists in targeting molecules containing a pair of well-defined and weakly coupled paramagnetic metal aggregates, each acting as a carrier of one potential qubit, (ii) the second is the design of dinuclear complexes of anisotropic metal ions, exhibiting dissimilar environments and feeble magnetic coupling. The first systems obtained from this synthetic program are presented here and their properties are discussed.

  20. Digital transmitter for data bus communications system

    NASA Technical Reports Server (NTRS)

    Proch, G. E. (Inventor)

    1975-01-01

    An improved digital transmitter for transmitting serial pulse code modulation (pcm) data at high bit rates over a transmission line is disclosed. When not transmitting, the transmitter features a high output impedance which prevents the transmitter from loading the transmission line. The pcm input is supplied to a logic control circuit which produces two discrete logic level signals which are supplied to an amplifier. The amplifier, which is transformer coupled to the output isolation circuitry, converts the discrete logic level signals to two high current level, ground isolated signals in the secondary windings of the coupling transformer. The latter signals are employed as inputs to the isolation circuitry which includes two series transistor pairs operating into a hybrid transformer functioning to isolate the transmitter circuitry from the transmission line.

  1. Generalized one-loop neutrino mass model with charged particles

    NASA Astrophysics Data System (ADS)

    Cheung, Kingman; Okada, Hiroshi

    2018-04-01

    We propose a radiative neutrino-mass model by introducing 3 generations of fermion pairs E-(N +1 )/2E+(N +1 )/2 and a couple of multicharged bosonic doublet fields ΦN /2,ΦN /2 +1, where N =1 , 3, 5, 7, 9. We show that the models can satisfy the neutrino masses and oscillation data, and are consistent with lepton-flavor violations, the muon anomalous magnetic moment, the oblique parameters, and the beta function of the U (1 )Y hypercharge gauge coupling. We also discuss the collider signals for various N , namely, multicharged leptons in the final state from the Drell-Yan production of E-(N +1 )/2E+(N +1 )/2. In general, the larger the N the more charged leptons will appear in the final state.

  2. Numerical solution of a coupled pair of elliptic equations from solid state electronics

    NASA Technical Reports Server (NTRS)

    Phillips, T. N.

    1983-01-01

    Iterative methods are considered for the solution of a coupled pair of second order elliptic partial differential equations which arise in the field of solid state electronics. A finite difference scheme is used which retains the conservative form of the differential equations. Numerical solutions are obtained in two ways, by multigrid and dynamic alternating direction implicit methods. Numerical results are presented which show the multigrid method to be an efficient way of solving this problem.

  3. Proximity-induced mixed odd- and even-frequency pairing in monolayer NbSe2

    NASA Astrophysics Data System (ADS)

    Aliabad, Mojtaba Rahimi; Zare, Mohammad-Hossein

    2018-06-01

    Monolayer superconducting transition-metal dichalcogenide NbSe2 is a candidate for a nodal topological superconductor by magnetic field. Because of the so-called Ising spin-orbit coupling that strongly pins the electron spins to the out-of-plane direction, Cooper pairs in monolayer superconductor NbSe2 are protected against an applied in-plane magnetic field much larger than the Pauli limit. In monolayer NbSe2, in addition to the Fermi pockets at the corners of Brillouin zone with opposite crystal momentum similar to other semiconducting transition-metal dichalcogenids, there is an extra Fermi pocket around the Γ point with much smaller spin splitting, which could lead to an alternative strategy for pairing possibilities that are manipulable by a smaller magnetic field. By considering a monolayer NbSe2-ferromagnet substrate junction, we explore the modified pairing correlations on the pocket at Γ point in hole-doped monolayer NbSe2. The underlying physics is fascinating as there is a delicate interplay of the induced exchange field and the Ising spin-orbit coupling. We realize a mixed singlet-triplet superconductivity, s +f , due to the Ising spin-orbit coupling. Moreover, our results reveal the admixture state including both odd- and even-frequency components, associated with the ferromagnetic proximity effect. Different frequency symmetries of the induced pairing correlations can be realized by manipulating the magnitude and direction of the induced magnetization.

  4. On the Harmonic Coupling of Components in Pairs of IIIb-III Bursts at Decameter Wavelengths

    NASA Astrophysics Data System (ADS)

    Brazhenko, A. I.; Melnik, V. N.; Frantsuzenko, A. V.; Dorovskyy, V. V.; Rucker, H. O.; Panchenko, M.

    2015-06-01

    The properties of IIIb-III pairs observed by the URAN-2 radioThe properties of IIIb-III pairs observed by the URAN-2 radiotelescope at frequencies 16-32 MHz are analyzed. Observations of these bursts were hold in April, June and September 2011. Durations, frequency drift rates, simultaneous frequency ratio of pairs components and their polarizations are analyzed. Pro and contra of IIIb-III harmonic connection are discussed.

  5. Ecological dynamics of continuous and categorical decision-making: the regatta start in sailing.

    PubMed

    Araújo, Duarte; Davids, Keith; Diniz, Ana; Rocha, Luis; Santos, João Coelho; Dias, Gonçalo; Fernandes, Orlando

    2015-01-01

    Ecological dynamics of decision-making in the sport of sailing exemplifies emergent, conditionally coupled, co-adaptive behaviours. In this study, observation of the coupling dynamics of paired boats during competitive sailing showed that decision-making can be modelled as a self-sustained, co-adapting system of informationally coupled oscillators (boats). Bytracing the spatial-temporal displacements of the boats, time series analyses (autocorrelations, periodograms and running correlations) revealed that trajectories of match racing boats are coupled more than 88% of the time during a pre-start race, via continuous, competing co-adaptions between boats. Results showed that both the continuously selected trajectories of the sailors (12 years of age) and their categorical starting point locations were examples of emergent decisions. In this dynamical conception of decision-making behaviours, strategic positioning (categorical) and continuous displacement of a boat over the course in match-race sailing emerged as a function of interacting task, personal and environmental constraints. Results suggest how key interacting constraints could be manipulated in practice to enhance sailors' perceptual attunement to them in competition.

  6. Tunable two-dimensional interfacial coupling in molecular heterostructures

    DOE PAGES

    Xu, Beibei; Chakraborty, Himanshu; Yadav, Vivek K.; ...

    2017-08-22

    Two-dimensional van der Waals heterostructures are of considerable interest for the next generation nanoelectronics because of their unique interlayer coupling and optoelectronic properties. Here, we report a modified Langmuir–Blodgett method to organize twodimensional molecular charge transfer crystals into arbitrarily and vertically stacked heterostructures, consisting of bis(ethylenedithio)tetrathiafulvalene (BEDT–TTF)/C 60 and poly (3-dodecylthiophene-2,5-diyl) (P3DDT)/C 60 nanosheets. A strong and anisotropic interfacial coupling between the charge transfer pairs is demonstrated. The van der Waals heterostructures exhibit pressure dependent sensitivity with a high piezoresistance coefficient of -4.4 × 10 -6 Pa -1, and conductance and capacitance tunable by external stimuli (ferroelectric field and magneticmore » field). Density functional theory calculations confirm charge transfer between the n-orbitals of the S atoms in BEDT–TTF of the BEDT–TTF/C 60 layer and the π* orbitals of C atoms in C 60 of the P3DDT/C 60 layer contribute to the inter-complex CT. Thus, the two-dimensional molecular van der Waals heterostructures with tunable optical–electronic–magnetic coupling properties are promising for flexible electronic applications.« less

  7. Coupled forward-backward trajectory approach for nonequilibrium electron-ion dynamics

    NASA Astrophysics Data System (ADS)

    Sato, Shunsuke A.; Kelly, Aaron; Rubio, Angel

    2018-04-01

    We introduce a simple ansatz for the wave function of a many-body system based on coupled forward and backward propagating semiclassical trajectories. This method is primarily aimed at, but not limited to, treating nonequilibrium dynamics in electron-phonon systems. The time evolution of the system is obtained from the Euler-Lagrange variational principle, and we show that this ansatz yields Ehrenfest mean-field theory in the limit that the forward and backward trajectories are orthogonal, and in the limit that they coalesce. We investigate accuracy and performance of this method by simulating electronic relaxation in the spin-boson model and the Holstein model. Although this method involves only pairs of semiclassical trajectories, it shows a substantial improvement over mean-field theory, capturing quantum coherence of nuclear dynamics as well as electron-nuclear correlations. This improvement is particularly evident in nonadiabatic systems, where the accuracy of this coupled trajectory method extends well beyond the perturbative electron-phonon coupling regime. This approach thus provides an attractive route forward to the ab initio description of relaxation processes, such as thermalization, in condensed phase systems.

  8. Transient nutation electron spin resonance spectroscopy on spin-correlated radical pairs: A theoretical analysis on hyperfine-induced nuclear modulations

    NASA Astrophysics Data System (ADS)

    Weber, Stefan; Kothe, Gerd; Norris, James R.

    1997-04-01

    The influence of anisotropic hyperfine interaction on transient nutation electron paramagnetic resonance (EPR) of light-induced spin-correlated radical pairs is studied theoretically using the density operator formalism. Analytical expressions for the time evolution of the transient EPR signal during selective microwave excitation of single transitions are derived for a model system comprised of a weakly coupled radical pair and one hyperfine-coupled nucleus with I=1/2. Zero-quantum electron coherence and single-quantum nuclear coherence are created as a result of the sudden light-induced generation of the radical pair state from a singlet-state precursor. Depending on the relative sizes of the nuclear Zeeman frequency and the secular and pseudo-secular parts of the hyperfine coupling, transitions between levels with different nuclear spin orientations are predicted to modulate the time-dependent EPR signal. These modulations are in addition to the well-known transient nutations and electron zero-quantum precessions. Our calculations provide insight into the mechanism of recent experimental observations of coherent nuclear modulations in the time-resolved EPR signals of doublets and radical pairs. Two distinct mechanisms of the modulations are presented for various microwave magnetic field strengths. The first modulation scheme arises from electron and nuclear coherences initiated by the laser excitation pulse and is "read out" by the weak microwave magnetic field. While the relative modulation depth of these oscillations with respect to the signal intensity is independent of the Rabi frequency, ω1, the frequencies of this coherence phenomenon are modulated by the effective microwave amplitude and determined by the nuclear Zeeman interaction and hyperfine coupling constants as well as the electron-electron spin exchange and dipolar interactions between the two radical pair halves. In a second mechanism the modulations are both created and detected by the microwave radiation. Here, the laser pulse merely defines the beginning of the microwave-induced coherent time evolution. This second mechanism appears the most consistent with current experimental observations.

  9. Evidence of Antiblockade in an Ultracold Rydberg Gas

    NASA Astrophysics Data System (ADS)

    Amthor, Thomas; Giese, Christian; Hofmann, Christoph S.; Weidemüller, Matthias

    2010-01-01

    We present the experimental observation of the antiblockade in an ultracold Rydberg gas recently proposed by Ates et al. [Phys. Rev. Lett. 98, 023002 (2007)PRLTAO0031-900710.1103/PhysRevLett.98.023002]. Our approach allows the control of the pair distribution in the gas and is based on a strong coupling of one transition in an atomic three-level system, while introducing specific detunings of the other transition. When the coupling energy matches the interaction energy of the Rydberg long-range interactions, the otherwise blocked excitation of close pairs becomes possible. A time-resolved spectroscopic measurement of the Penning ionization signal is used to identify slight variations in the Rydberg pair distribution of a random arrangement of atoms. A model based on a pair interaction Hamiltonian is presented which well reproduces our experimental observations and allows one to deduce the distribution of nearest-neighbor distances.

  10. Ab initio characterization of coupling strength for all types of dangling-bond pairs on the hydrogen-terminated Si(100)-2 × 1 surface

    NASA Astrophysics Data System (ADS)

    Shaterzadeh-Yazdi, Zahra; Sanders, Barry C.; DiLabio, Gino A.

    2018-04-01

    Recent work has suggested that coupled silicon dangling bonds sharing an excess electron may serve as building blocks for quantum-cellular-automata cells and quantum computing schemes when constructed on hydrogen-terminated silicon surfaces. In this work, we employ ab initio density-functional theory to examine the details associated with the coupling between two dangling bonds sharing one excess electron and arranged in various configurations on models of phosphorous-doped hydrogen-terminated silicon (100) surfaces. Our results show that the coupling strength depends strongly on the relative orientation of the dangling bonds on the surface and on the separation between them. The orientation of dangling bonds is determined by the anisotropy of the silicon (100) surface, so this feature of the surface is a significant contributing factor to variations in the strength of coupling between dangling bonds. The results demonstrate that simple models for approximating tunneling, such as the Wentzel-Kramer-Brillouin method, which do not incorporate the details of surface structure, are incapable of providing reasonable estimates of tunneling rates between dangling bonds. The results provide guidance to efforts related to the development of dangling-bond based computing elements.

  11. A Search for Physics Beyond the Standard Model using Like-Sign Muon Pairs in pp Collisions at Center of Mass Energy = 7 TeV with the ATLAS Detector

    NASA Astrophysics Data System (ADS)

    Skinnari, Louise Anastasia

    This dissertation presents a search for physics beyond the Standard Model using pairs of muons with equal electric charge. The search is performed in a proton-proton collision data sample collected during 2011 at s = 7 TeV by the ATLAS experiment at the Large Hadron Collider. The total data sample corresponds to an integrated luminosity of 4.7 fb -1. Events are selected by requiring pairs of prompt and isolated like-sign muons with transverse momentum greater than 20 GeV. The observed dimuon invariant mass distribution is compared to the Standard Model expectation, searching for any deviation between the observed and predicted yields. No evidence for an excess beyond the Standard Model expectation is observed. The results are interpreted as inclusive cross-section limits on the production of like-sign muon pairs from non-Standard Model sources as function of the dimuon invariant mass. The cross-section limits range between 30 fb and 1.2 fb. The data are also searched for a new narrow resonance which decays to like-sign muon pairs. No evidence for such resonant production is observed and the results are interpreted as upper limits on the mass and production cross section of doubly charged Higgs bosons. Assuming pair-production and a 100% branching ratio to muons, masses below 398 GeV (306 GeV) are excluded assuming coupling to left-handed (right-handed) fermions.

  12. Mining Time-Resolved Functional Brain Graphs to an EEG-Based Chronnectomic Brain Aged Index (CBAI).

    PubMed

    Dimitriadis, Stavros I; Salis, Christos I

    2017-01-01

    The brain at rest consists of spatially and temporal distributed but functionally connected regions that called intrinsic connectivity networks (ICNs). Resting state electroencephalography (rs-EEG) is a way to characterize brain networks without confounds associated with task EEG such as task difficulty and performance. A novel framework of how to study dynamic functional connectivity under the notion of functional connectivity microstates (FCμstates) and symbolic dynamics is further discussed. Furthermore, we introduced a way to construct a single integrated dynamic functional connectivity graph (IDFCG) that preserves both the strength of the connections between every pair of sensors but also the type of dominant intrinsic coupling modes (DICM). The whole methodology is demonstrated in a significant and unexplored task for EEG which is the definition of an objective Chronnectomic Brain Aged index (CBAI) extracted from resting-state data ( N = 94 subjects) with both eyes-open and eyes-closed conditions. Novel features have been defined based on symbolic dynamics and the notion of DICM and FCμstates. The transition rate of FCμstates, the symbolic dynamics based on the evolution of FCμstates (the Markovian Entropy, the complexity index), the probability distribution of DICM, the novel Flexibility Index that captures the dynamic reconfiguration of DICM per pair of EEG sensors and the relative signal power constitute a valuable pool of features that can build the proposed CBAI. Here we applied a feature selection technique and Extreme Learning Machine (ELM) classifier to discriminate young adults from middle-aged and a Support Vector Regressor to build a linear model of the actual age based on EEG-based spatio-temporal features. The most significant type of features for both prediction of age and discrimination of young vs. adults age groups was the dynamic reconfiguration of dominant coupling modes derived from a subset of EEG sensor pairs. Specifically, our results revealed a very high prediction of age for eyes-open ( R 2 = 0.60; y = 0.79x + 8.03) and lower for eyes-closed ( R 2 = 0.48; y = 0.71x + 10.91) while we succeeded to correctly classify young vs. middle-age group with 97.8% accuracy in eyes-open and 87.2% for eyes-closed. Our results were reproduced also in a second dataset for further external validation of the whole analysis. The proposed methodology proved valuable for the characterization of the intrinsic properties of dynamic functional connectivity through the age untangling developmental differences using EEG resting-state recordings.

  13. Localised Nonlinear Waves in the Three-Component Coupled Hirota Equations

    NASA Astrophysics Data System (ADS)

    Xu, Tao; Chen, Yong

    2017-10-01

    We construct the Lax pair and Darboux transformation for the three-component coupled Hirota equations including higher-order effects such as third-order dispersion, self-steepening, and stimulated Raman scattering. A special vector solution of the Lax pair with 4×4 matrices for the three-component Hirota system is elaborately generated, based on this vector solution, various types of mixed higher-order localised waves are derived through the generalised Darboux transformation. Instead of considering various arrangements of the three potential functions q1, q2, and q3, here, the same combination is considered as the same type solution. The first- and second-order localised waves are mainly discussed in six mixed types: (1) the hybrid solutions degenerate to the rational ones and three components are all rogue waves; (2) two components are hybrid solutions between rogue wave (RW) and breather (RW+breather), and one component is interactional solution between RW and dark soliton (RW+dark soliton); (3) two components are RW+dark soliton, and one component is RW+bright soliton; (4) two components are RW+breather, and one component is RW+bright soliton; (5) two components are RW+dark soliton, and one component is RW+bright soliton; (6) three components are all RW+breather. Moreover, these nonlinear localised waves merge with each other by increasing the absolute values of two free parameters α, β. These results further uncover some striking dynamic structures in the multicomponent coupled system.

  14. Superfluid density and condensate fraction in the BCS-BEC crossover regime at finite temperatures

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

    Fukushima, N.; Ohashi, Y.; Faculty of Science and Technology, Keio University, Hiyoshi, Yokohama 223

    2007-03-15

    The superfluid density is a fundamental quantity describing the response to a rotation as well as in two-fluid collisional hydrodynamics. We present extensive calculations of the superfluid density {rho}{sub s} in the BCS-BEC crossover regime of a uniform superfluid Fermi gas at finite temperatures. We include strong-coupling or fluctuation effects on these quantities within a Gaussian approximation. We also incorporate the same fluctuation effects into the BCS single-particle excitations described by the superfluid order parameter {delta} and Fermi chemical potential {mu}, using the Nozieres-Schmitt-Rink approximation. This treatment is shown to be necessary for consistent treatment of {rho}{sub s} over themore » entire BCS-BEC crossover. We also calculate the condensate fraction N{sub c} as a function of the temperature, a quantity which is quite different from the superfluid density {rho}{sub s}. We show that the mean-field expression for the condensate fraction N{sub c} is a good approximation even in the strong-coupling BEC regime. Our numerical results show how {rho}{sub s} and N{sub c} depend on temperature, from the weak-coupling BCS region to the BEC region of tightly bound Cooper pair molecules. In a companion paper [Phys. Rev. A 74, 063626 (2006)], we derive an equivalent expression for {rho}{sub s} from the thermodynamic potential, which exhibits the role of the pairing fluctuations in a more explicit manner.« less

  15. Electrical and chemical transmission between striatal GABAergic output neurones in rat brain slices

    PubMed Central

    Venance, Laurent; Glowinski, Jacques; Giaume, Christian

    2004-01-01

    Basal ganglia are interconnected subcortical nuclei, connected to the thalamus and all cortical areas involved in sensory motor control, limbic functions and cognition. The striatal output neurones (SONs), the major striatal population, are believed to act as detectors and integrators of distributed patterns of cerebral cortex inputs. Despite the key role of SONs in cortico-striatal information processing, little is known about their local interactions. Here, we report the existence and characterization of electrical and GABAergic transmission between SONs in rat brain slices. Tracer coupling (biocytin) incidence was high during the first two postnatal weeks and then decreased (postnatal days (P) 5–25, 60%; P25–30, 29%; n = 61). Electrical coupling was observed between 27% of SON pairs (coupling coefficient: 3.1 ± 0.3%, n = 89 at P15) and as shown by single-cell RT-PCR, several connexin (Cx) mRNAs were found to be expressed (Cx31.1, Cx32, Cx36 and Cx47). GABAergic synaptic transmission (abolished by bicuculline, a GABAA receptor antagonist) observed in 19% of SON pairs (n = 62) was reliable (mean failure rate of 6 ± 3%), precise (variation coefficient of latency, 0.06), strong (IPSC amplitudes of 38 ± 12 pA) and unidirectional. Interestingly, electrical and chemical transmission were mutually exclusive. These results suggest that preferential networks of electrically and chemically connected SONs, might be involved in the channelling of cortico-basal ganglia information processing. PMID:15235091

  16. Unifying mechanical and thermodynamic descriptions across the thioredoxin protein family.

    PubMed

    Mottonen, James M; Xu, Minli; Jacobs, Donald J; Livesay, Dennis R

    2009-05-15

    We compare various predicted mechanical and thermodynamic properties of nine oxidized thioredoxins (TRX) using a Distance Constraint Model (DCM). The DCM is based on a nonadditive free energy decomposition scheme, where entropic contributions are determined from rigidity and flexibility of structure based on distance constraints. We perform averages over an ensemble of constraint topologies to calculate several thermodynamic and mechanical response functions that together yield quantitative stability/flexibility relationships (QSFR). Applied to the TRX protein family, QSFR metrics display a rich variety of similarities and differences. In particular, backbone flexibility is well conserved across the family, whereas cooperativity correlation describing mechanical and thermodynamic couplings between the residue pairs exhibit distinctive features that readily standout. The diversity in predicted QSFR metrics that describe cooperativity correlation between pairs of residues is largely explained by a global flexibility order parameter describing the amount of intrinsic flexibility within the protein. A free energy landscape is calculated as a function of the flexibility order parameter, and key values are determined where the native-state, transition-state, and unfolded-state are located. Another key value identifies a mechanical transition where the global nature of the protein changes from flexible to rigid. The key values of the flexibility order parameter help characterize how mechanical and thermodynamic response is linked. Variation in QSFR metrics and key characteristics of global flexibility are related to the native state X-ray crystal structure primarily through the hydrogen bond network. Furthermore, comparison of three TRX redox pairs reveals differences in thermodynamic response (i.e., relative melting point) and mechanical properties (i.e., backbone flexibility and cooperativity correlation) that are consistent with experimental data on thermal stabilities and NMR dynamical profiles. The results taken together demonstrate that small-scale structural variations are amplified into discernible global differences by propagating mechanical couplings through the H-bond network.

  17. Anharmonicity and Octahedral Tilting in Hybrid Vacancy-Ordered Double Perovskites

    DOE PAGES

    Maughan, Annalise E.; Ganose, Alex M.; Candia, Andrew M.; ...

    2017-11-30

    The advantageous performance of hybrid organic-inorganic perovskite halide semiconduc- tors in optoelectronic applications motivates studies of their fundamental crystal-chemistry. In particular, recent studies have sought to understand how dipolar, dynamic, and organic cations, such as methylammonium (CH 3 NH 3 + ) and formamidinium (CH(NH 2 ) 2 + ) affect physical properties such as light absorption and charge transport. Here, to probe the influence of organic- inorganic coupling on charge transport, we have prepared the series of vacancy-ordered double perovskite derivatives, A 2SnI 6, where A = Cs +, CH 3NH 3 +, and CH(NH 2) 2 +. Despitemore » nearly identical cubic structures by powder X-ray diffraction, replacement of Cs + with CH 3NH 3 + or CH(NH 2) 2 + reduces conductivity through a reduction in both carrier concentration and carrier mobility. We attribute the trends in electronic behavior to anharmonic lattice dynamics from the formation of hydrogen bonds that yield coupled organic-inorganic dynamics. This anharmonicity manifests as asymmetry of the inter-octahedral I-I pair correlations in the X-ray pair distribution function of the hybrid compounds, which can be modeled by large atomistic ensembles with random rotations of rigid [SnI 6] octahedral units. The presence of soft, anharmonic lattice dynamics holds implications for electron-phonon interactions, as supported by calculation of electron-phonon coupling strength that indicates the formation of more tightly-bound polarons and reduced electron mobilities with increasing cation size. Finally, by exploiting the relatively decoupled nature of the octahedral units in these defect-ordered perovskite variants, we can interrogate the impact of organic-inorganic coupling and lattice anharmonicity on the charge transport behavior of hybrid perovskite halide semiconductors.« less

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

    Maughan, Annalise E.; Ganose, Alex M.; Candia, Andrew M.

    The advantageous performance of hybrid organic-inorganic perovskite halide semiconduc- tors in optoelectronic applications motivates studies of their fundamental crystal-chemistry. In particular, recent studies have sought to understand how dipolar, dynamic, and organic cations, such as methylammonium (CH 3 NH 3 + ) and formamidinium (CH(NH 2 ) 2 + ) affect physical properties such as light absorption and charge transport. Here, to probe the influence of organic- inorganic coupling on charge transport, we have prepared the series of vacancy-ordered double perovskite derivatives, A 2SnI 6, where A = Cs +, CH 3NH 3 +, and CH(NH 2) 2 +. Despitemore » nearly identical cubic structures by powder X-ray diffraction, replacement of Cs + with CH 3NH 3 + or CH(NH 2) 2 + reduces conductivity through a reduction in both carrier concentration and carrier mobility. We attribute the trends in electronic behavior to anharmonic lattice dynamics from the formation of hydrogen bonds that yield coupled organic-inorganic dynamics. This anharmonicity manifests as asymmetry of the inter-octahedral I-I pair correlations in the X-ray pair distribution function of the hybrid compounds, which can be modeled by large atomistic ensembles with random rotations of rigid [SnI 6] octahedral units. The presence of soft, anharmonic lattice dynamics holds implications for electron-phonon interactions, as supported by calculation of electron-phonon coupling strength that indicates the formation of more tightly-bound polarons and reduced electron mobilities with increasing cation size. Finally, by exploiting the relatively decoupled nature of the octahedral units in these defect-ordered perovskite variants, we can interrogate the impact of organic-inorganic coupling and lattice anharmonicity on the charge transport behavior of hybrid perovskite halide semiconductors.« less

  19. Memory reactivation during rest supports upcoming learning of related content.

    PubMed

    Schlichting, Margaret L; Preston, Alison R

    2014-11-04

    Although a number of studies have highlighted the importance of offline processes for memory, how these mechanisms influence future learning remains unknown. Participants with established memories for a set of initial face-object associations were scanned during passive rest and during encoding of new related and unrelated pairs of objects. Spontaneous reactivation of established memories and enhanced hippocampal-neocortical functional connectivity during rest was related to better subsequent learning, specifically of related content. Moreover, the degree of functional coupling during rest was predictive of neural engagement during the new learning experience itself. These results suggest that through rest-phase reactivation and hippocampal-neocortical interactions, existing memories may come to facilitate encoding during subsequent related episodes.

  20. Memory reactivation during rest supports upcoming learning of related content

    PubMed Central

    Schlichting, Margaret L.; Preston, Alison R.

    2014-01-01

    Although a number of studies have highlighted the importance of offline processes for memory, how these mechanisms influence future learning remains unknown. Participants with established memories for a set of initial face–object associations were scanned during passive rest and during encoding of new related and unrelated pairs of objects. Spontaneous reactivation of established memories and enhanced hippocampal–neocortical functional connectivity during rest was related to better subsequent learning, specifically of related content. Moreover, the degree of functional coupling during rest was predictive of neural engagement during the new learning experience itself. These results suggest that through rest-phase reactivation and hippocampal–neocortical interactions, existing memories may come to facilitate encoding during subsequent related episodes. PMID:25331890

  1. Phases of a fermionic model with chiral condensates and Cooper pairs in 1+1 dimensions

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

    Mihaila, Bogdan; Blagoev, Krastan B.; MIND Institute, Albuquerque, New Mexico 87131

    2006-01-01

    We study the phase structure of a 4-fermi model with three bare coupling constants, which potentially has three types of bound states. This model is a generalization of the model discussed previously by [A. Chodos, F. Cooper, W. Mao, H. Minakata, and A. Singh, Phys. Rev. D 61, 045011 (2000).], which contained both chiral condensates and Cooper pairs. For this generalization we find that there are two independent renormalized coupling constants which determine the phase structure at finite density and temperature. We find that the vacuum can be in one of three distinct phases depending on the value of thesemore » two renormalized coupling constants.« less

  2. Exciton-phonon coupling in diindenoperylene thin films

    NASA Astrophysics Data System (ADS)

    Heinemeyer, U.; Scholz, R.; Gisslén, L.; Alonso, M. I.; Ossó, J. O.; Garriga, M.; Hinderhofer, A.; Kytka, M.; Kowarik, S.; Gerlach, A.; Schreiber, F.

    2008-08-01

    We investigate exciton-phonon coupling and exciton transfer in diindenoperylene (DIP) thin films on oxidized Si substrates by analyzing the dielectric function determined by variable-angle spectroscopic ellipsometry. Since the molecules in the thin-film phase form crystallites that are randomly oriented azimuthally and highly oriented along the surface normal, DIP films exhibit strongly anisotropic optical properties with uniaxial symmetry. This anisotropy can be determined by multiple sample analysis. The thin-film spectrum is compared with a monomer spectrum in solution, which reveals similar vibronic subbands and a Huang-Rhys parameter of S≈0.87 for an effective internal vibration at ℏωeff=0.17eV . However, employing these parameters the observed dielectric function of the DIP films cannot be described by a pure Frenkel exciton model, and the inclusion of charge-transfer (CT) states becomes mandatory. A model Hamiltonian is parametrized with density-functional theory calculations of single DIP molecules and molecule pairs in the stacking geometry of the thin-film phase, revealing the vibronic coupling constants of DIP in its excited and charged states together with electron and hole transfer integrals along the stack. From a fit of the model calculation to the observed dielectric tensor, we find the lowest CT transition E00CT at 0.26±0.05eV above the neutral molecular excitation energy E00F , which is an important parameter for device applications.

  3. Long-range coupling of electron-hole pairs in spatially separated organic donor-acceptor layers

    PubMed Central

    Nakanotani, Hajime; Furukawa, Taro; Morimoto, Kei; Adachi, Chihaya

    2016-01-01

    Understanding exciton behavior in organic semiconductor molecules is crucial for the development of organic semiconductor-based excitonic devices such as organic light-emitting diodes and organic solar cells, and the tightly bound electron-hole pair forming an exciton is normally assumed to be localized on an organic semiconducting molecule. We report the observation of long-range coupling of electron-hole pairs in spatially separated electron-donating and electron-accepting molecules across a 10-nanometers-thick spacer layer. We found that the exciton energy can be tuned over 100 megaelectron volts and the fraction of delayed fluorescence can be increased by adjusting the spacer-layer thickness. Furthermore, increasing the spacer-layer thickness produced an organic light-emitting diode with an electroluminescence efficiency nearly eight times higher than that of a device without a spacer layer. Our results demonstrate the first example of a long-range coupled charge-transfer state between electron-donating and electron-accepting molecules in a working device. PMID:26933691

  4. Spin-orbit coupling, electron transport and pairing instabilities in two-dimensional square structures

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

    Kocharian, Armen N.; Fernando, Gayanath W.; Fang, Kun

    Rashba spin-orbit effects and electron correlations in the two-dimensional cylindrical lattices of square geometries are assessed using mesoscopic two-, three- and four-leg ladder structures. Here the electron transport properties are systematically calculated by including the spin-orbit coupling in tight binding and Hubbard models threaded by a magnetic flux. These results highlight important aspects of possible symmetry breaking mechanisms in square ladder geometries driven by the combined effect of a magnetic gauge field spin-orbit interaction and temperature. The observed persistent current, spin and charge polarizations in the presence of spin-orbit coupling are driven by separation of electron and hole charges andmore » opposite spins in real-space. The modeled spin-flip processes on the pairing mechanism induced by the spin-orbit coupling in assembled nanostructures (as arrays of clusters) engineered in various two-dimensional multi-leg structures provide an ideal playground for understanding spatial charge and spin density inhomogeneities leading to electron pairing and spontaneous phase separation instabilities in unconventional superconductors. Such studies also fall under the scope of current challenging problems in superconductivity and magnetism, topological insulators and spin dependent transport associated with numerous interfaces and heterostructures.« less

  5. Exploring peptide hormones in plants: identification of four peptide hormone-receptor pairs and two post-translational modification enzymes

    PubMed Central

    MATSUBAYASHI, Yoshikatsu

    2018-01-01

    The identification of hormones and their receptors in multicellular organisms is one of the most exciting research areas and has lead to breakthroughs in understanding how their growth and development are regulated. In particular, peptide hormones offer advantages as cell-to-cell signals in that they can be synthesized rapidly and have the greatest diversity in their structure and function. Peptides often undergo post-translational modifications and proteolytic processing to generate small oligopeptide hormones. In plants, such small post-translationally modified peptides constitute the largest group of peptide hormones. We initially explored this type of peptide hormone using bioassay-guided fractionation and later by in silico gene screening coupled with biochemical peptide detection, which led to the identification of four types of novel peptide hormones in plants. We also identified specific receptors for these peptides and transferases required for their post-translational modification. This review summarizes how we discovered these peptide hormone–receptor pairs and post-translational modification enzymes, and how these molecules function in plant growth, development and environmental adaptation. PMID:29434080

  6. Exploring peptide hormones in plants: identification of four peptide hormone-receptor pairs and two post-translational modification enzymes.

    PubMed

    Matsubayashi, Yoshikatsu

    2018-01-01

    The identification of hormones and their receptors in multicellular organisms is one of the most exciting research areas and has lead to breakthroughs in understanding how their growth and development are regulated. In particular, peptide hormones offer advantages as cell-to-cell signals in that they can be synthesized rapidly and have the greatest diversity in their structure and function. Peptides often undergo post-translational modifications and proteolytic processing to generate small oligopeptide hormones. In plants, such small post-translationally modified peptides constitute the largest group of peptide hormones. We initially explored this type of peptide hormone using bioassay-guided fractionation and later by in silico gene screening coupled with biochemical peptide detection, which led to the identification of four types of novel peptide hormones in plants. We also identified specific receptors for these peptides and transferases required for their post-translational modification. This review summarizes how we discovered these peptide hormone-receptor pairs and post-translational modification enzymes, and how these molecules function in plant growth, development and environmental adaptation.

  7. Finite-T correlations and free exchange-correlation energy of quasi-one-dimensional electron gas

    NASA Astrophysics Data System (ADS)

    Garg, Vinayak; Sharma, Akariti; Moudgil, R. K.

    2018-02-01

    We have studied the effect of temperature on static density-density correlations and plasmon excitation spectrum of quasi-one-dimensional electron gas (Q1DEG) using the random phase approximation (RPA). Numerical results for static structure factor, pair-correlation function, static density susceptibility, free exchange-correlation energy and plasmon dispersion are presented over a wide range of temperature and electron density. As an interesting result, we find that the short-range correlations exhibit a non-monotonic dependence on temperature T, initially growing stronger (i.e. the pair-correlation function at small inter-electron spacing assuming relatively smaller values) with increasing T and then weakening above a critical T. The cross-over temperature is found to increase with increasing coupling among electrons. Also, the q = 2kF peak in the static density susceptibility χ(q,ω = 0,T) at T = 0 K smears out with rising T. The free exchange-correlation energy and plasmon dispersion show a significant variation with T, and the trend is qualitatively the same as in higher dimensions.

  8. Differences in Brain Activity during a Verbal Associative Memory Encoding Task in High- and Low-fit Adolescents

    PubMed Central

    Herting, Megan M.; Nagel, Bonnie J.

    2013-01-01

    Aerobic fitness is associated with better memory performance as well as larger volumes in memory-related brain regions in children, adolescents, and elderly. It is unclear if aerobic exercise also influences learning and memory functional neural circuitry. Here, we examine brain activity in 17 high-fit (HF) and 17 low-fit (LF) adolescents during a subsequent memory encoding paradigm using fMRI. Despite similar memory performance, HF and LF youth displayed a number of differences in memory-related and default mode (DMN) brain regions during encoding later remembered versus forgotten word pairs. Specifically, HF youth displayed robust deactivation in DMN areas, including the ventral medial PFC and posterior cingulate cortex, whereas LF youth did not show this pattern. Furthermore, LF youth showed greater bilateral hippocampal and right superior frontal gyrus activation during encoding of later remembered versus forgotten word pairs. Follow-up task-dependent functional correlational analyses showed differences in hippocampus and DMN activity coupling during successful encoding between the groups, suggesting aerobic fitness during adolescents may impact functional connectivity of the hippocampus and DMN during memory encoding. To our knowledge, this study is the first to examine the influence of aerobic fitness on hippocampal function and memory-related neural circuitry using fMRI. Taken together with previous research, these findings suggest aerobic fitness can influence not only memory-related brain structure, but also brain function. PMID:23249350

  9. Search for Higgs boson pair production in events with two bottom quarks and two tau leptons in proton-proton collisions at √{ s } = 13TeV

    NASA Astrophysics Data System (ADS)

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M.; Grohsjean, A.; Gunnellini, P.; Harb, A.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Kasemann, M.; Keaveney, J.; Kleinwort, C.; Korol, I.; Krücker, D.; Lange, W.; Lelek, A.; Lenz, T.; Leonard, J.; Lipka, K.; Lohmann, W.; Mankel, R.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Ntomari, E.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Roland, B.; Savitskyi, M.; Saxena, P.; Shevchenko, R.; Spannagel, S.; Stefaniuk, N.; Van Onsem, G. P.; Walsh, R.; Wen, Y.; Wichmann, K.; Wissing, C.; Zenaiev, O.; Bein, S.; Blobel, V.; Centis Vignali, M.; Dreyer, T.; Garutti, E.; Gonzalez, D.; Haller, J.; Hinzmann, A.; Hoffmann, M.; Karavdina, A.; Klanner, R.; Kogler, R.; Kovalchuk, N.; Kurz, S.; Lapsien, T.; Marchesini, I.; Marconi, D.; Meyer, M.; Niedziela, M.; Nowatschin, D.; Pantaleo, F.; Peiffer, T.; Perieanu, A.; Scharf, C.; Schleper, P.; Schmidt, A.; Schumann, S.; Schwandt, J.; Sonneveld, J.; Stadie, H.; Steinbrück, G.; Stober, F. M.; Stöver, M.; Tholen, H.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Vormwald, B.; Akbiyik, M.; Barth, C.; Baur, S.; Butz, E.; Caspart, R.; Chwalek, T.; Colombo, F.; De Boer, W.; Dierlamm, A.; Freund, B.; Friese, R.; Giffels, M.; Gilbert, A.; Haitz, D.; Hartmann, F.; Heindl, S. M.; Husemann, U.; Kassel, F.; Kudella, S.; Mildner, H.; Mozer, M. U.; Müller, Th.; Plagge, M.; Quast, G.; Rabbertz, K.; Schröder, M.; Shvetsov, I.; Sieber, G.; Simonis, H. J.; Ulrich, R.; Wayand, S.; Weber, M.; Weiler, T.; Williamson, S.; Wöhrmann, C.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Topsis-Giotis, I.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Evangelou, I.; Foudas, C.; Kokkas, P.; Mallios, S.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Strologas, J.; Triantis, F. A.; Csanad, M.; Filipovic, N.; Pasztor, G.; Bencze, G.; Hajdu, C.; Horvath, D.; Hunyadi, Á.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Makovec, A.; Molnar, J.; Szillasi, Z.; Bartók, M.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Choudhury, S.; Komaragiri, J. R.; Bahinipati, S.; Bhowmik, S.; Mal, P.; Mandal, K.; Nayak, A.; Sahoo, D. K.; Sahoo, N.; Swain, S. K.; Bansal, S.; Beri, S. B.; Bhatnagar, V.; Bhawandeep, U.; Chawla, R.; Dhingra, N.; Kalsi, A. K.; Kaur, A.; Kaur, M.; Kumar, R.; Kumari, P.; Mehta, A.; Singh, J. B.; Walia, G.; Kumar, Ashok; Shah, Aashaq; Bhardwaj, A.; Chauhan, S.; Choudhary, B. C.; Garg, R. B.; Keshri, S.; Kumar, A.; Malhotra, S.; Naimuddin, M.; Ranjan, K.; Sharma, R.; Sharma, V.; Bhardwaj, R.; Bhattacharya, R.; Bhattacharya, S.; Dey, S.; Dutt, S.; Dutta, S.; Ghosh, S.; Majumdar, N.; Modak, A.; Mondal, K.; Mukhopadhyay, S.; Nandan, S.; Purohit, A.; Roy, A.; Roy, D.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Thakur, S.; Behera, P. K.; Chudasama, R.; Dutta, D.; Jha, V.; Kumar, V.; Mohanty, A. K.; Netrakanti, P. K.; Pant, L. 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M.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Caputo, C.; Colaleo, A.; Creanza, D.; Cristella, L.; De Filippis, N.; De Palma, M.; Errico, F.; Fiore, L.; Iaselli, G.; Lezki, S.; Maggi, G.; Maggi, M.; Miniello, G.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Ranieri, A.; Selvaggi, G.; Sharma, A.; Silvestris, L.; Venditti, R.; Verwilligen, P.; Abbiendi, G.; Battilana, C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Chhibra, S. S.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Rossi, A. M.; Rovelli, T.; Siroli, G. 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W.; Moon, C. S.; Oh, Y. D.; Sekmen, S.; Son, D. C.; Yang, Y. C.; Lee, A.; Kim, H.; Moon, D. H.; Oh, G.; Brochero Cifuentes, J. A.; Goh, J.; Kim, T. J.; Cho, S.; Choi, S.; Go, Y.; Gyun, D.; Ha, S.; Hong, B.; Jo, Y.; Kim, Y.; Lee, K.; Lee, K. S.; Lee, S.; Lim, J.; Park, S. K.; Roh, Y.; Almond, J.; Kim, J.; Kim, J. S.; Lee, H.; Lee, K.; Nam, K.; Oh, S. B.; Radburn-Smith, B. C.; Seo, S. h.; Yang, U. K.; Yoo, H. D.; Yu, G. B.; Choi, M.; Kim, H.; Kim, J. H.; Lee, J. S. H.; Park, I. C.; Ryu, G.; Choi, Y.; Hwang, C.; Lee, J.; Yu, I.; Dudenas, V.; Juodagalvis, A.; Vaitkus, J.; Ahmed, I.; Ibrahim, Z. A.; Md Ali, M. A. B.; Mohamad Idris, F.; Wan Abdullah, W. A. T.; Yusli, M. N.; Zolkapli, Z.; Duran-Osuna, M. C.; Castilla-Valdez, H.; De La Cruz-Burelo, E.; Heredia-De La Cruz, I.; Lopez-Fernandez, R.; Mejia Guisao, J.; Rabadán-Trejo, R. I.; Ramirez-Sanchez, G.; Reyes-Almanza, R.; Sanchez-Hernandez, A.; Carrillo Moreno, S.; Oropeza Barrera, C.; Vazquez Valencia, F.; Pedraza, I.; Salazar Ibarguen, H. A.; Uribe Estrada, C.; Morelos Pineda, A.; Krofcheck, D.; Butler, P. H.; Ahmad, A.; Ahmad, M.; Hassan, Q.; Hoorani, H. R.; Saddique, A.; Shah, M. A.; Shoaib, M.; Waqas, M.; Bialkowska, H.; Bluj, M.; Boimska, B.; Frueboes, T.; Górski, M.; Kazana, M.; Nawrocki, K.; Romanowska-Rybinska, K.; Szleper, M.; Zalewski, P.; Bunkowski, K.; Byszuk, A.; Doroba, K.; Kalinowski, A.; Konecki, M.; Krolikowski, J.; Misiura, M.; Olszewski, M.; Pyskir, A.; Walczak, M.; Bargassa, P.; Beirão Da Cruz E Silva, C.; Calpas, B.; Di Francesco, A.; Faccioli, P.; Gallinaro, M.; Hollar, J.; Leonardo, N.; Lloret Iglesias, L.; Nemallapudi, M. V.; Seixas, J.; Toldaiev, O.; Vadruccio, D.; Varela, J.; Afanasiev, S.; Bunin, P.; Gavrilenko, M.; Golutvin, I.; Gorbunov, I.; Kamenev, A.; Karjavin, V.; Lanev, A.; Malakhov, A.; Matveev, V.; Palichik, V.; Perelygin, V.; Shmatov, S.; Shulha, S.; Skatchkov, N.; Smirnov, V.; Voytishin, N.; Zarubin, A.; Ivanov, Y.; Kim, V.; Kuznetsova, E.; Levchenko, P.; Murzin, V.; Oreshkin, V.; Smirnov, I.; Sulimov, V.; Uvarov, L.; Vavilov, S.; Vorobyev, A.; Andreev, Yu.; Dermenev, A.; Gninenko, S.; Golubev, N.; Karneyeu, A.; Kirsanov, M.; Krasnikov, N.; Pashenkov, A.; Tlisov, D.; Toropin, A.; Epshteyn, V.; Gavrilov, V.; Lychkovskaya, N.; Popov, V.; Pozdnyakov, I.; Safronov, G.; Spiridonov, A.; Stepennov, A.; Toms, M.; Vlasov, E.; Zhokin, A.; Aushev, T.; Bylinkin, A.; Chistov, R.; Danilov, M.; Parygin, P.; Philippov, D.; Polikarpov, S.; Tarkovskii, E.; Andreev, V.; Azarkin, M.; Dremin, I.; Kirakosyan, M.; Terkulov, A.; Baskakov, A.; Belyaev, A.; Boos, E.; Bunichev, V.; Dubinin, M.; Dudko, L.; Ershov, A.; Gribushin, A.; Klyukhin, V.; Kodolova, O.; Lokhtin, I.; Miagkov, I.; Obraztsov, S.; Petrushanko, S.; Savrin, V.; Blinov, V.; Skovpen, Y.; Shtol, D.; Azhgirey, I.; Bayshev, I.; Bitioukov, S.; Elumakhov, D.; Kachanov, V.; Kalinin, A.; Konstantinov, D.; Krychkine, V.; Petrov, V.; Ryutin, R.; Sobol, A.; Troshin, S.; Tyurin, N.; Uzunian, A.; Volkov, A.; Adzic, P.; Cirkovic, P.; Devetak, D.; Dordevic, M.; Milosevic, J.; Rekovic, V.; Alcaraz Maestre, J.; Barrio Luna, M.; Cerrada, M.; Colino, N.; De La Cruz, B.; Delgado Peris, A.; Escalante Del Valle, A.; Fernandez Bedoya, C.; Fernández Ramos, J. P.; Flix, J.; Fouz, M. C.; Garcia-Abia, P.; Gonzalez Lopez, O.; Goy Lopez, S.; Hernandez, J. M.; Josa, M. I.; Pérez-Calero Yzquierdo, A.; Puerta Pelayo, J.; Quintario Olmeda, A.; Redondo, I.; Romero, L.; Soares, M. S.; Álvarez Fernández, A.; de Trocóniz, J. F.; Missiroli, M.; Moran, D.; Cuevas, J.; Erice, C.; Fernandez Menendez, J.; Gonzalez Caballero, I.; González Fernández, J. R.; Palencia Cortezon, E.; Sanchez Cruz, S.; Suárez Andrés, I.; Vischia, P.; Vizan Garcia, J. M.; Cabrillo, I. J.; Calderon, A.; Chazin Quero, B.; Curras, E.; Fernandez, M.; Garcia-Ferrero, J.; Gomez, G.; Lopez Virto, A.; Marco, J.; Martinez Rivero, C.; Martinez Ruiz del Arbol, P.; Matorras, F.; Piedra Gomez, J.; Rodrigo, T.; Ruiz-Jimeno, A.; Scodellaro, L.; Trevisani, N.; Vila, I.; Vilar Cortabitarte, R.; Abbaneo, D.; Auffray, E.; Baillon, P.; Ball, A. H.; Barney, D.; Bianco, M.; Bloch, P.; Bocci, A.; Botta, C.; Camporesi, T.; Castello, R.; Cepeda, M.; Cerminara, G.; Chapon, E.; Chen, Y.; d'Enterria, D.; Dabrowski, A.; Daponte, V.; David, A.; De Gruttola, M.; De Roeck, A.; Di Marco, E.; Dobson, M.; Dorney, B.; du Pree, T.; Dünser, M.; Dupont, N.; Elliott-Peisert, A.; Everaerts, P.; Franzoni, G.; Fulcher, J.; Funk, W.; Gigi, D.; Gill, K.; Glege, F.; Gulhan, D.; Gundacker, S.; Guthoff, M.; Harris, P.; Hegeman, J.; Innocente, V.; Janot, P.; Karacheban, O.; Kieseler, J.; Kirschenmann, H.; Knünz, V.; Kornmayer, A.; Kortelainen, M. J.; Lange, C.; Lecoq, P.; Lourenço, C.; Lucchini, M. T.; Malgeri, L.; Mannelli, M.; Martelli, A.; Meijers, F.; Merlin, J. A.; Mersi, S.; Meschi, E.; Milenovic, P.; Moortgat, F.; Mulders, M.; Neugebauer, H.; Orfanelli, S.; Orsini, L.; Pape, L.; Perez, E.; Peruzzi, M.; Petrilli, A.; Petrucciani, G.; Pfeiffer, A.; Pierini, M.; Racz, A.; Reis, T.; Rolandi, G.; Rovere, M.; Sakulin, H.; Schäfer, C.; Schwick, C.; Seidel, M.; Selvaggi, M.; Sharma, A.; Silva, P.; Sphicas, P.; Steggemann, J.; Stoye, M.; Tosi, M.; Treille, D.; Triossi, A.; Tsirou, A.; Veckalns, V.; Veres, G. I.; Verweij, M.; Wardle, N.; Zeuner, W. D.; Bertl, W.; Caminada, L.; Deiters, K.; Erdmann, W.; Horisberger, R.; Ingram, Q.; Kaestli, H. C.; Kotlinski, D.; Langenegger, U.; Rohe, T.; Wiederkehr, S. A.; Bachmair, F.; Bäni, L.; Berger, P.; Bianchini, L.; Casal, B.; Dissertori, G.; Dittmar, M.; Donegà, M.; Grab, C.; Heidegger, C.; Hits, D.; Hoss, J.; Kasieczka, G.; Klijnsma, T.; Lustermann, W.; Mangano, B.; Marionneau, M.; Meinhard, M. T.; Meister, D.; Micheli, F.; Musella, P.; Nessi-Tedaldi, F.; Pandolfi, F.; Pata, J.; Pauss, F.; Perrin, G.; Perrozzi, L.; Quittnat, M.; Schönenberger, M.; Shchutska, L.; Tavolaro, V. R.; Theofilatos, K.; Vesterbacka Olsson, M. L.; Wallny, R.; Zagozdzinska, A.; Zhu, D. H.; Aarrestad, T. K.; Amsler, C.; Canelli, M. F.; De Cosa, A.; Del Burgo, R.; Donato, S.; Galloni, C.; Hreus, T.; Kilminster, B.; Ngadiuba, J.; Pinna, D.; Rauco, G.; Robmann, P.; Salerno, D.; Seitz, C.; Takahashi, Y.; Zucchetta, A.; Candelise, V.; Doan, T. H.; Jain, Sh.; Khurana, R.; Kuo, C. M.; Lin, W.; Pozdnyakov, A.; Yu, S. S.; Kumar, Arun; Chang, P.; Chao, Y.; Chen, K. F.; Chen, P. H.; Fiori, F.; Hou, W.-S.; Hsiung, Y.; Liu, Y. F.; Lu, R.-S.; Miñano Moya, M.; Paganis, E.; Psallidas, A.; Tsai, J. f.; Asavapibhop, B.; Kovitanggoon, K.; Singh, G.; Srimanobhas, N.; Adiguzel, A.; Boran, F.; Cerci, S.; Damarseckin, S.; Demiroglu, Z. S.; Dozen, C.; Dumanoglu, I.; Girgis, S.; Gokbulut, G.; Guler, Y.; Hos, I.; Kangal, E. E.; Kara, O.; Kayis Topaksu, A.; Kiminsu, U.; Oglakci, M.; Onengut, G.; Ozdemir, K.; Sunar Cerci, D.; Tali, B.; Turkcapar, S.; Zorbakir, I. S.; Zorbilmez, C.; Bilin, B.; Karapinar, G.; Ocalan, K.; Yalvac, M.; Zeyrek, M.; Gülmez, E.; Kaya, M.; Kaya, O.; Tekten, S.; Yetkin, E. A.; Agaras, M. N.; Atay, S.; Cakir, A.; Cankocak, K.; Grynyov, B.; Levchuk, L.; Sorokin, P.; Aggleton, R.; Ball, F.; Beck, L.; Brooke, J. J.; Burns, D.; Clement, E.; Cussans, D.; Davignon, O.; Flacher, H.; Goldstein, J.; Grimes, M.; Heath, G. P.; Heath, H. F.; Jacob, J.; Kreczko, L.; Lucas, C.; Newbold, D. M.; Paramesvaran, S.; Poll, A.; Sakuma, T.; Seif El Nasr-storey, S.; Smith, D.; Smith, V. J.; Bell, K. W.; Belyaev, A.; Brew, C.; Brown, R. M.; Calligaris, L.; Cieri, D.; Cockerill, D. J. A.; Coughlan, J. A.; Harder, K.; Harper, S.; Olaiya, E.; Petyt, D.; Shepherd-Themistocleous, C. H.; Thea, A.; Tomalin, I. R.; Williams, T.; Bainbridge, R.; Breeze, S.; Buchmuller, O.; Bundock, A.; Casasso, S.; Citron, M.; Colling, D.; Corpe, L.; Dauncey, P.; Davies, G.; De Wit, A.; Della Negra, M.; Di Maria, R.; Elwood, A.; Haddad, Y.; Hall, G.; Iles, G.; James, T.; Lane, R.; Laner, C.; Lyons, L.; Magnan, A.-M.; Malik, S.; Mastrolorenzo, L.; Matsushita, T.; Nash, J.; Nikitenko, A.; Palladino, V.; Pesaresi, M.; Raymond, D. M.; Richards, A.; Rose, A.; Scott, E.; Seez, C.; Shtipliyski, A.; Summers, S.; Tapper, A.; Uchida, K.; Vazquez Acosta, M.; Virdee, T.; Winterbottom, D.; Wright, J.; Zenz, S. C.; Cole, J. E.; Hobson, P. R.; Khan, A.; Kyberd, P.; Reid, I. D.; Symonds, P.; Teodorescu, L.; Turner, M.; Borzou, A.; Call, K.; Dittmann, J.; Hatakeyama, K.; Liu, H.; Pastika, N.; Smith, C.; Bartek, R.; Dominguez, A.; Buccilli, A.; Cooper, S. I.; Henderson, C.; Rumerio, P.; West, C.; Arcaro, D.; Avetisyan, A.; Bose, T.; Gastler, D.; Rankin, D.; Richardson, C.; Rohlf, J.; Sulak, L.; Zou, D.; Benelli, G.; Cutts, D.; Garabedian, A.; Hakala, J.; Heintz, U.; Hogan, J. M.; Kwok, K. H. M.; Laird, E.; Landsberg, G.; Mao, Z.; Narain, M.; Piperov, S.; Sagir, S.; Syarif, R.; Yu, D.; Band, R.; Brainerd, C.; Burns, D.; Calderon De La Barca Sanchez, M.; Chertok, M.; Conway, J.; Conway, R.; Cox, P. T.; Erbacher, R.; Flores, C.; Funk, G.; Gardner, M.; Ko, W.; Lander, R.; Mclean, C.; Mulhearn, M.; Pellett, D.; Pilot, J.; Shalhout, S.; Shi, M.; Smith, J.; Squires, M.; Stolp, D.; Tos, K.; Tripathi, M.; Wang, Z.; Bachtis, M.; Bravo, C.; Cousins, R.; Dasgupta, A.; Florent, A.; Hauser, J.; Ignatenko, M.; Mccoll, N.; Saltzberg, D.; Schnaible, C.; Valuev, V.; Bouvier, E.; Burt, K.; Clare, R.; Ellison, J.; Gary, J. W.; Ghiasi Shirazi, S. M. A.; Hanson, G.; Heilman, J.; Jandir, P.; Kennedy, E.; Lacroix, F.; Long, O. R.; Olmedo Negrete, M.; Paneva, M. I.; Shrinivas, A.; Si, W.; Wang, L.; Wei, H.; Wimpenny, S.; Yates, B. R.; Branson, J. G.; Cittolin, S.; Derdzinski, M.; Hashemi, B.; Holzner, A.; Klein, D.; Kole, G.; Krutelyov, V.; Letts, J.; Macneill, I.; Masciovecchio, M.; Olivito, D.; Padhi, S.; Pieri, M.; Sani, M.; Sharma, V.; Simon, S.; Tadel, M.; Vartak, A.; Wasserbaech, S.; Wood, J.; Würthwein, F.; Yagil, A.; Zevi Della Porta, G.; Amin, N.; Bhandari, R.; Bradmiller-Feld, J.; Campagnari, C.; Dishaw, A.; Dutta, V.; Franco Sevilla, M.; George, C.; Golf, F.; Gouskos, L.; Gran, J.; Heller, R.; Incandela, J.; Mullin, S. D.; Ovcharova, A.; Qu, H.; Richman, J.; Stuart, D.; Suarez, I.; Yoo, J.; Anderson, D.; Bendavid, J.; Bornheim, A.; Lawhorn, J. M.; Newman, H. B.; Nguyen, T.; Pena, C.; Spiropulu, M.; Vlimant, J. R.; Xie, S.; Zhang, Z.; Zhu, R. Y.; Andrews, M. B.; Ferguson, T.; Mudholkar, T.; Paulini, M.; Russ, J.; Sun, M.; Vogel, H.; Vorobiev, I.; Weinberg, M.; Cumalat, J. P.; Ford, W. T.; Jensen, F.; Johnson, A.; Krohn, M.; Leontsinis, S.; Mulholland, T.; Stenson, K.; Wagner, S. R.; Alexander, J.; Chaves, J.; Chu, J.; Dittmer, S.; Mcdermott, K.; Mirman, N.; Patterson, J. R.; Rinkevicius, A.; Ryd, A.; Skinnari, L.; Soffi, L.; Tan, S. M.; Tao, Z.; Thom, J.; Tucker, J.; Wittich, P.; Zientek, M.; Abdullin, S.; Albrow, M.; Apollinari, G.; Apresyan, A.; Apyan, A.; Banerjee, S.; Bauerdick, L. A. T.; Beretvas, A.; Berryhill, J.; Bhat, P. C.; Bolla, G.; Burkett, K.; Butler, J. N.; Canepa, A.; Cerati, G. B.; Cheung, H. W. K.; Chlebana, F.; Cremonesi, M.; Duarte, J.; Elvira, V. D.; Freeman, J.; Gecse, Z.; Gottschalk, E.; Gray, L.; Green, D.; Grünendahl, S.; Gutsche, O.; Harris, R. M.; Hasegawa, S.; Hirschauer, J.; Hu, Z.; Jayatilaka, B.; Jindariani, S.; Johnson, M.; Joshi, U.; Klima, B.; Kreis, B.; Lammel, S.; Lincoln, D.; Lipton, R.; Liu, M.; Liu, T.; Lopes De Sá, R.; Lykken, J.; Maeshima, K.; Magini, N.; Marraffino, J. M.; Maruyama, S.; Mason, D.; McBride, P.; Merkel, P.; Mrenna, S.; Nahn, S.; O'Dell, V.; Pedro, K.; Prokofyev, O.; Rakness, G.; Ristori, L.; Schneider, B.; Sexton-Kennedy, E.; Soha, A.; Spalding, W. J.; Spiegel, L.; Stoynev, S.; Strait, J.; Strobbe, N.; Taylor, L.; Tkaczyk, S.; Tran, N. V.; Uplegger, L.; Vaandering, E. W.; Vernieri, C.; Verzocchi, M.; Vidal, R.; Wang, M.; Weber, H. A.; Whitbeck, A.; Acosta, D.; Avery, P.; Bortignon, P.; Bourilkov, D.; Brinkerhoff, A.; Carnes, A.; Carver, M.; Curry, D.; Das, S.; Field, R. D.; Furic, I. K.; Konigsberg, J.; Korytov, A.; Kotov, K.; Ma, P.; Matchev, K.; Mei, H.; Mitselmakher, G.; Rank, D.; Sperka, D.; Terentyev, N.; Thomas, L.; Wang, J.; Wang, S.; Yelton, J.; Joshi, Y. R.; Linn, S.; Markowitz, P.; Rodriguez, J. L.; Ackert, A.; Adams, T.; Askew, A.; Hagopian, S.; Hagopian, V.; Johnson, K. F.; Kolberg, T.; Martinez, G.; Perry, T.; Prosper, H.; Saha, A.; Santra, A.; Yohay, R.; Baarmand, M. M.; Bhopatkar, V.; Colafranceschi, S.; Hohlmann, M.; Noonan, D.; Roy, T.; Yumiceva, F.; Adams, M. R.; Apanasevich, L.; Berry, D.; Betts, R. R.; Cavanaugh, R.; Chen, X.; Evdokimov, O.; Gerber, C. E.; Hangal, D. A.; Hofman, D. J.; Jung, K.; Kamin, J.; Sandoval Gonzalez, I. D.; Tonjes, M. B.; Trauger, H.; Varelas, N.; Wang, H.; Wu, Z.; Zhang, J.; Bilki, B.; Clarida, W.; Dilsiz, K.; Durgut, S.; Gandrajula, R. P.; Haytmyradov, M.; Khristenko, V.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Snyder, C.; Tiras, E.; Wetzel, J.; Yi, K.; Blumenfeld, B.; Cocoros, A.; Eminizer, N.; Fehling, D.; Feng, L.; Gritsan, A. V.; Maksimovic, P.; Roskes, J.; Sarica, U.; Swartz, M.; Xiao, M.; You, C.; Al-bataineh, A.; Baringer, P.; Bean, A.; Boren, S.; Bowen, J.; Castle, J.; Khalil, S.; Kropivnitskaya, A.; Majumder, D.; Mcbrayer, W.; Murray, M.; Royon, C.; Sanders, S.; Schmitz, E.; Stringer, R.; Tapia Takaki, J. D.; Wang, Q.; Ivanov, A.; Kaadze, K.; Maravin, Y.; Mohammadi, A.; Saini, L. K.; Skhirtladze, N.; Toda, S.; Rebassoo, F.; Wright, D.; Anelli, C.; Baden, A.; Baron, O.; Belloni, A.; Calvert, B.; Eno, S. C.; Ferraioli, C.; Hadley, N. J.; Jabeen, S.; Jeng, G. Y.; Kellogg, R. G.; Kunkle, J.; Mignerey, A. C.; Ricci-Tam, F.; Shin, Y. H.; Skuja, A.; Tonwar, S. C.; Abercrombie, D.; Allen, B.; Azzolini, V.; Barbieri, R.; Baty, A.; Bi, R.; Brandt, S.; Busza, W.; Cali, I. A.; D'Alfonso, M.; Demiragli, Z.; Gomez Ceballos, G.; Goncharov, M.; Hsu, D.; Iiyama, Y.; Innocenti, G. M.; Klute, M.; Kovalskyi, D.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Maier, B.; Marini, A. C.; Mcginn, C.; Mironov, C.; Narayanan, S.; Niu, X.; Paus, C.; Roland, C.; Roland, G.; Salfeld-Nebgen, J.; Stephans, G. S. F.; Tatar, K.; Velicanu, D.; Wang, J.; Wang, T. W.; Wyslouch, B.; Benvenuti, A. C.; Chatterjee, R. M.; Evans, A.; Hansen, P.; Kalafut, S.; Kubota, Y.; Lesko, Z.; Mans, J.; Nourbakhsh, S.; Ruckstuhl, N.; Rusack, R.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bloom, K.; Claes, D. R.; Fangmeier, C.; Gonzalez Suarez, R.; Kamalieddin, R.; Kravchenko, I.; Monroy, J.; Siado, J. E.; Snow, G. R.; Stieger, B.; Alyari, M.; Dolen, J.; Godshalk, A.; Harrington, C.; Iashvili, I.; Nguyen, D.; Parker, A.; Rappoccio, S.; Roozbahani, B.; Alverson, G.; Barberis, E.; Hortiangtham, A.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Teixeira De Lima, R.; Trocino, D.; Wood, D.; Bhattacharya, S.; Charaf, O.; Hahn, K. A.; Mucia, N.; Odell, N.; Pollack, B.; Schmitt, M. H.; Sung, K.; Trovato, M.; Velasco, M.; Dev, N.; Hildreth, M.; Hurtado Anampa, K.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Loukas, N.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Planer, M.; Reinsvold, A.; Ruchti, R.; Smith, G.; Taroni, S.; Wayne, M.; Wolf, M.; Woodard, A.; Alimena, J.; Antonelli, L.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Francis, B.; Hart, A.; Hill, C.; Ji, W.; Liu, B.; Luo, W.; Puigh, D.; Winer, B. L.; Wulsin, H. W.; Benaglia, A.; Cooperstein, S.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Higginbotham, S.; Lange, D.; Luo, J.; Marlow, D.; Mei, K.; Ojalvo, I.; Olsen, J.; Palmer, C.; Piroué, P.; Stickland, D.; Tully, C.; Malik, S.; Norberg, S.; Barker, A.; Barnes, V. E.; Folgueras, S.; Gutay, L.; Jha, M. K.; Jones, M.; Jung, A. W.; Khatiwada, A.; Miller, D. H.; Neumeister, N.; Peng, C. C.; Schulte, J. F.; Sun, J.; Wang, F.; Xie, W.; Cheng, T.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.; Bodek, A.; de Barbaro, P.; Demina, R.; Duh, Y. t.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Han, J.; Hindrichs, O.; Khukhunaishvili, A.; Lo, K. H.; Tan, P.; Verzetti, M.; Ciesielski, R.; Goulianos, K.; Mesropian, C.; Agapitos, A.; Chou, J. P.; Gershtein, Y.; Gómez Espinosa, T. A.; Halkiadakis, E.; Heindl, M.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Kyriacou, S.; Lath, A.; Montalvo, R.; Nash, K.; Osherson, M.; Saka, H.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Delannoy, A. G.; Foerster, M.; Heideman, J.; Riley, G.; Rose, K.; Spanier, S.; Thapa, K.; Bouhali, O.; Castaneda Hernandez, A.; Celik, A.; Dalchenko, M.; De Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Gilmore, J.; Huang, T.; Kamon, T.; Mueller, R.; Pakhotin, Y.; Patel, R.; Perloff, A.; Perniè, L.; Rathjens, D.; Safonov, A.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Damgov, J.; De Guio, F.; Dudero, P. R.; Faulkner, J.; Gurpinar, E.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Peltola, T.; Undleeb, S.; Volobouev, I.; Wang, Z.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Melo, A.; Ni, H.; Sheldon, P.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Barria, P.; Cox, B.; Hirosky, R.; Ledovskoy, A.; Li, H.; Neu, C.; Sinthuprasith, T.; Sun, X.; Wang, Y.; Wolfe, E.; Xia, F.; Harr, R.; Karchin, P. E.; Sturdy, J.; Zaleski, S.; Brodski, M.; Buchanan, J.; Caillol, C.; Dasu, S.; Dodd, L.; Duric, S.; Gomber, B.; Grothe, M.; Herndon, M.; Hervé, A.; Hussain, U.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Pierro, G. A.; Polese, G.; Ruggles, T.; Savin, A.; Smith, N.; Smith, W. H.; Taylor, D.; Woods, N.; CMS Collaboration

    2018-03-01

    A search for the production of Higgs boson pairs in proton-proton collisions at a centre-of-mass energy of 13 TeV is presented, using a data sample corresponding to an integrated luminosity of 35.9fb-1 collected with the CMS detector at the LHC. Events with one Higgs boson decaying into two bottom quarks and the other decaying into two τ leptons are explored to investigate both resonant and nonresonant production mechanisms. The data are found to be consistent, within uncertainties, with the standard model background predictions. For resonant production, upper limits at the 95% confidence level are set on the production cross section for Higgs boson pairs as a function of the hypothesized resonance mass and are interpreted in the context of the minimal supersymmetric standard model. For nonresonant production, upper limits on the production cross section constrain the parameter space for anomalous Higgs boson couplings. The observed (expected) upper limit at 95% confidence level corresponds to about 30 (25) times the prediction of the standard model.

  10. Coupled pendula chains under parametric PT-symmetric driving force

    NASA Astrophysics Data System (ADS)

    Destyl, E.; Nuiro, S. P.; Pelinovsky, D. E.; Poullet, P.

    2017-12-01

    We consider a chain of coupled pendula pairs, where each pendulum is connected to the nearest neighbors in the longitudinal and transverse directions. The common strings in each pair are modulated periodically by an external force. In the limit of small coupling and near the 1 : 2 parametric resonance, we derive a novel system of coupled PT-symmetric discrete nonlinear Schrödinger equations, which has Hamiltonian symmetry but has no phase invariance. By using the conserved energy, we find the parameter range for the linear and nonlinear stability of the zero equilibrium. Numerical experiments illustrate how destabilization of the zero equilibrium takes place when the stability constraints are not satisfied. The central pendulum excites nearest pendula and this process continues until a dynamical equilibrium is reached where each pendulum in the chain oscillates at a finite amplitude.

  11. Coupling Spatiotemporal Community Assembly Processes to Changes in Microbial Metabolism

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

    Graham, Emily B.; Crump, Alex R.; Resch, Charles T.

    Community assembly processes govern shifts in species abundances in response to environmental change, yet our understanding of assembly remains largely decoupled from ecosystem function. Here, we test hypotheses regarding assembly and function across space and time using hyporheic microbial communities as a model system. We pair sampling of two habitat types through hydrologic fluctuation with null modeling and multivariate statistics. We demonstrate that dual selective pressures assimilate to generate compositional changes at distinct timescales among habitat types, resulting in contrasting associations of Betaproteobacteria and Thaumarchaeota with selection and with seasonal changes in aerobic metabolism. Our results culminate in a conceptualmore » model in which selection from contrasting environments regulates taxon abundance and ecosystem function through time, with increases in function when oscillating selection opposes stable selective pressures. Our model is applicable within both macrobial and microbial ecology and presents an avenue for assimilating community assembly processes into predictions of ecosystem function.« less

  12. Centromere Pairing in Early Meiotic Prophase Requires Active Centromeres and Precedes Installation of the Synaptonemal Complex in Maize[W

    PubMed Central

    Zhang, Jing; Pawlowski, Wojciech P.; Han, Fangpu

    2013-01-01

    Pairing of homologous chromosomes in meiosis is critical for their segregation to daughter cells. In most eukaryotes, clustering of telomeres precedes and facilitates chromosome pairing. In several species, centromeres also form pairwise associations, known as coupling, before the onset of pairing. We found that, in maize (Zea mays), centromere association begins at the leptotene stage and occurs earlier than the formation of the telomere bouquet. We established that centromere pairing requires centromere activity and the sole presence of centromeric repeats is not sufficient for pairing. In several species, homologs of the ZIP1 protein, which forms the central element of the synaptonemal complex in budding yeast (Saccharomyces cerevisiae), play essential roles in centromere coupling. However, we found that the maize ZIP1 homolog ZYP1 installs in the centromeric regions of chromosomes after centromeres form associations. Instead, we found that maize STRUCTURAL MAINTENANCE OF CHROMOSOMES6 homolog forms a central element of the synaptonemal complex, which is required for centromere associations. These data shed light on the poorly understood mechanism of centromere interactions and suggest that this mechanism may vary somewhat in different species. PMID:24143803

  13. Centromere pairing in early meiotic prophase requires active centromeres and precedes installation of the synaptonemal complex in maize.

    PubMed

    Zhang, Jing; Pawlowski, Wojciech P; Han, Fangpu

    2013-10-01

    Pairing of homologous chromosomes in meiosis is critical for their segregation to daughter cells. In most eukaryotes, clustering of telomeres precedes and facilitates chromosome pairing. In several species, centromeres also form pairwise associations, known as coupling, before the onset of pairing. We found that, in maize (Zea mays), centromere association begins at the leptotene stage and occurs earlier than the formation of the telomere bouquet. We established that centromere pairing requires centromere activity and the sole presence of centromeric repeats is not sufficient for pairing. In several species, homologs of the ZIP1 protein, which forms the central element of the synaptonemal complex in budding yeast (Saccharomyces cerevisiae), play essential roles in centromere coupling. However, we found that the maize ZIP1 homolog ZYP1 installs in the centromeric regions of chromosomes after centromeres form associations. Instead, we found that maize structural maintenance of chromosomes6 homolog forms a central element of the synaptonemal complex, which is required for centromere associations. These data shed light on the poorly understood mechanism of centromere interactions and suggest that this mechanism may vary somewhat in different species.

  14. Cluster dynamics of pulse coupled oscillators

    NASA Astrophysics Data System (ADS)

    O'Keeffe, Kevin; Strogatz, Steven; Krapivsky, Paul

    2015-03-01

    We study the dynamics of networks of pulse coupled oscillators. Much attention has been devoted to the ultimate fate of the system: which conditions lead to a steady state in which all the oscillators are firing synchronously. But little is known about how synchrony builds up from an initially incoherent state. The current work addresses this question. Oscillators start to synchronize by forming clusters of different sizes that fire in unison. First pairs of oscillators, then triplets and so on. These clusters progressively grow by coalescing with others, eventually resulting in the fully synchronized state. We study the mean field model in which the coupling between oscillators is all to all. We use probabilistic arguments to derive a recursive set of evolution equations for these clusters. Using a generating function formalism, we derive simple equations for the moments of these clusters. Our results are in good agreement simulation. We then numerically explore the effects of non-trivial connectivity. Our results have potential application to ultra-low power ``impulse radio'' & sensor networks.

  15. TRILEX and G W +EDMFT approach to d -wave superconductivity in the Hubbard model

    NASA Astrophysics Data System (ADS)

    Vučičević, J.; Ayral, T.; Parcollet, O.

    2017-09-01

    We generalize the recently introduced TRILEX approach (TRiply irreducible local EXpansion) to superconducting phases. The method treats simultaneously Mott and spin-fluctuation physics using an Eliashberg theory supplemented by local vertex corrections determined by a self-consistent quantum impurity model. We show that, in the two-dimensional Hubbard model, at strong coupling, TRILEX yields a d -wave superconducting dome as a function of doping. Contrary to the standard cluster dynamical mean field theory (DMFT) approaches, TRILEX can capture d -wave pairing using only a single-site effective impurity model. We also systematically explore the dependence of the superconducting temperature on the bare dispersion at weak coupling, which shows a clear link between strong antiferromagnetic (AF) correlations and the onset of superconductivity. We identify a combination of hopping amplitudes particularly favorable to superconductivity at intermediate doping. Finally, we study within G W +EDMFT the low-temperature d -wave superconducting phase at strong coupling in a region of parameter space with reduced AF fluctuations.

  16. Molecular structure and interactions in the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.

    PubMed

    Dhumal, Nilesh R; Noack, Kristina; Kiefer, Johannes; Kim, Hyung J

    2014-04-03

    Electronic structure theory (density functional and Møller-Plesset perturbation theory) and vibrational spectroscopy (FT-IR and Raman) are employed to study molecular interactions in the room-temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. Different conformers of a cation-anion pair based on their molecular interactions are simulated in the gas phase and in a dielectric continuum solvent environment. Although the ordering of conformers in energy varies with theoretical methods, their predictions for three lowest energy conformers in the gas phase are similar. Strong C-H---N interactions between the acidic hydrogen atom of the cation imidazole ring and the nitrogen atom of the anion are predicted for either the lowest or second lowest energy conformer. In a continuum solvent, different theoretical methods yield the same ion-pair conformation for the lowest energy state. In both phases, the density functional method predicts that the anion is in a trans conformation in the lowest energy ion pair state. The theoretical results are compared with experimental observations from Raman scattering and IR absorption spectroscopies and manifestations of the molecular interactions in the vibrational spectra are discussed. The directions of the frequency shifts of the characteristic vibrations relative to the free anion and cation are explained by calculating the difference electron density coupled with electron density topography.

  17. Persistence of the gapless spin liquid in the breathing kagome Heisenberg antiferromagnet

    NASA Astrophysics Data System (ADS)

    Iqbal, Yasir; Poilblanc, Didier; Thomale, Ronny; Becca, Federico

    2018-03-01

    The nature of the ground state of the spin S =1 /2 Heisenberg antiferromagnet on the kagome lattice with breathing anisotropy (i.e., with different superexchange couplings J▵ and J▿ within elementary up- and down-pointing triangles) is investigated within the framework of Gutzwiller projected fermionic wave functions and Monte Carlo methods. We analyze the stability of the U(1 ) Dirac spin liquid with respect to the presence of fermionic pairing that leads to a gapped Z2 spin liquid. For several values of the ratio J▿/J▵ , the size scaling of the energy gain due to the pairing fields and the variational parameters are reported. Our results show that the energy gain of the gapped spin liquid with respect to the gapless state either vanishes for large enough system size or scales to zero in the thermodynamic limit. Similarly, the optimized pairing amplitudes (responsible for opening the spin gap) are shown to vanish in the thermodynamic limit. Our outcome is corroborated by the application of one and two Lanczos steps to the gapless and gapped wave functions, for which no energy gain of the gapped state is detected when improving the quality of the variational states. Finally, we discuss the competition with the "simplex" Z2 resonating-valence-bond spin liquid, valence-bond crystal, and nematic states in the strongly anisotropic regime, i.e., J▿≪J▵ .

  18. Electronic coupling between Watson-Crick pairs for hole transfer and transport in desoxyribonucleic acid

    NASA Astrophysics Data System (ADS)

    Voityuk, Alexander A.; Jortner, Joshua; Bixon, M.; Rösch, Notker

    2001-04-01

    Electronic matrix elements for hole transfer between Watson-Crick pairs in desoxyribonucleic acid (DNA) of regular structure, calculated at the Hartree-Fock level, are compared with the corresponding intrastrand and interstrand matrix elements estimated for models comprised of just two nucleobases. The hole transfer matrix element of the GAG trimer duplex is calculated to be larger than that of the GTG duplex. "Through-space" interaction between two guanines in the trimer duplexes is comparable with the coupling through an intervening Watson-Crick pair. The gross features of bridge specificity and directional asymmetry of the electronic matrix elements for hole transfer between purine nucleobases in superstructures of dimer and trimer duplexes have been discussed on the basis of the quantum chemical calculations. These results have also been analyzed with a semiempirical superexchange model for the electronic coupling in DNA duplexes of donor (nuclobases)-acceptor, which incorporates adjacent base-base electronic couplings and empirical energy gaps corrected for solvation effects; this perturbation-theory-based model interpretation allows a theoretical evaluation of experimental observables, i.e., the absolute values of donor-acceptor electronic couplings, their distance dependence, and the reduction factors for the intrastrand hole hopping or trapping rates upon increasing the size of the nucleobases bridge. The quantum chemical results point towards some limitations of the perturbation-theory-based modeling.

  19. Dimension-six operators in Higgs boson pair production via vector-boson fusion at the LHC

    NASA Astrophysics Data System (ADS)

    Ling, Liu-Sheng; Zhang, Ren-You; Ma, Wen-Gan; Li, Xiao-Zhou; Guo, Lei; Wang, Shao-Ming

    2017-09-01

    The effective Lagrangian formalism provides a way to study the new physics effects at the electroweak scale. We study Higgs pair production via vector-boson fusion (VBF) at the Large Hadron Collider within the framework of the effective field theory. The effects from the dimension-six operators involved in VBF Higgs pair production are investigated, particularly OΦ ,2 and OΦ ,3 , which are relevant to the triple Higgs self-coupling, on the integrated cross section and various kinematic distributions. We find that the distributions of Higgs-pair invariant mass, Higgs transverse momentum, and rapidity are significantly altered by the operators OΦ ,2 and OΦ ,3 . These features are helpful in disentangling the contributions from the operators OΦ ,2 and OΦ ,3 in triple Higgs self-coupling. We also provide the 5 σ discovery and 3 σ exclusion limits for the coefficients of OΦ ,2 and OΦ ,3 by measuring the VBF Higgs pair-production process, including the sequential H →b b ¯ decays at the 14 TeV LHC.

  20. Spin-selective coupling to Majorana zero modes in mixed singlet and triplet superconducting nanowires

    NASA Astrophysics Data System (ADS)

    Paul, Ganesh C.; Saha, Arijit; Das, Sourin

    2018-05-01

    We theoretically investigate the transport properties of a quasi-one-dimensional ferromagnet-superconductor junction where the superconductor consists of mixed singlet and triplet pairings. We show that the relative orientation of the Stoner field (h ˜) in the ferromagnetic lead and the d vector of the superconductor acts like a on-off switch for the zero bias conductance of the device. In the regime, where triplet pairing amplitude dominates over the singlet counterpart (topological phase), a pair of Majorana zero modes appear at each end of the superconducting part of the nanowire. When h ˜ is parallel or antiparallel to the d vector, transport gets completely blocked due to blockage in pairing while, when h ˜ and d are perpendicular to each other, the zero energy two terminal differential conductance spectra exhibits sharp transition from 4 e2/h to 2 e2/h as the magnetization strength in the lead becomes larger than the chemical potential indicating the spin-selective coupling of a pair of Majorana zero modes to the lead.

  1. Recombination, Pairing, and Synapsis of Homologs during Meiosis

    PubMed Central

    Zickler, Denise; Kleckner, Nancy

    2015-01-01

    Recombination is a prominent feature of meiosis in which it plays an important role in increasing genetic diversity during inheritance. Additionally, in most organisms, recombination also plays mechanical roles in chromosomal processes, most notably to mediate pairing of homologous chromosomes during prophase and, ultimately, to ensure regular segregation of homologous chromosomes when they separate at the first meiotic division. Recombinational interactions are also subject to important spatial patterning at both early and late stages. Recombination-mediated processes occur in physical and functional linkage with meiotic axial chromosome structure, with interplay in both directions, before, during, and after formation and dissolution of the synaptonemal complex (SC), a highly conserved meiosis-specific structure that links homolog axes along their lengths. These diverse processes also are integrated with recombination-independent interactions between homologous chromosomes, nonhomology-based chromosome couplings/clusterings, and diverse types of chromosome movement. This review provides an overview of these diverse processes and their interrelationships. PMID:25986558

  2. Reactanceless synthesized impedance bandpass amplifier

    NASA Technical Reports Server (NTRS)

    Kleinberg, L. L. (Inventor)

    1985-01-01

    An active R bandpass filter network is formed by four operational amplifier stages interconnected by discrete resistances. One pair of stages synthesize an equivalent input impedance of an inductance (L sub eq) in parallel with a discrete resistance (R sub o) while the second pair of stages synthesizes an equivalent input impedance of a capacitance (C sub eq) serially coupled to another discrete resistance (R sub i) coupled in parallel with the first two stages. The equivalent input impedances aggregately define a tuned resonant bandpass filter in the roll-off regions of the operational amplifiers.

  3. Magnetic switch coupling to synchronize magnetic modulators

    DOEpatents

    Reed, K.W.; Kiekel, P.

    1999-04-27

    Apparatus for synchronizing the output pulses from a pair of magnetic switches is disclosed. An electrically conductive loop is provided between the pair of switches with the loop having windings about the core of each of the magnetic switches. The magnetic coupling created by the loop removes voltage and timing variations between the outputs of the two magnetic switches caused by any of a variety of factors. The only remaining variation is a very small fixed timing offset caused by the geometry and length of the loop itself. 13 figs.

  4. Probes labelled with energy transfer coupled dyes

    DOEpatents

    Mathies, R.A.; Glazer, A.; Ju, J.

    1997-11-18

    Compositions are provided comprising sets of fluorescent labels carrying pairs of donor and acceptor dye molecules, designed for efficient excitation of the donors at a single wavelength and emission from the acceptor in each of the pairs at different wavelengths. The different molecules having different donor-acceptor pairs can be modified to have substantially the same mobility under separation conditions, by varying the distance between the donor and acceptor in a given pair. Particularly, the fluorescent compositions find use as labels in sequencing nucleic acids. 7 figs.

  5. Probes labelled with energy transfer coupled dyes

    DOEpatents

    Mathies, Richard A.; Glazer, Alexander; Ju, Jingyue

    1997-01-01

    Compositions are provided comprising sets of fluorescent labels carrying pairs of donor and acceptor dye molecules, designed for efficient excitation of the donors at a single wavelength and emission from the acceptor in each of the pairs at different wavelengths. The different molecules having different donor-acceptor pairs can be modified to have substantially the same mobility under separation conditions, by varying the distance between the donor and acceptor in a given pair. Particularly, the fluorescent compositions find use as labels in sequencing nucleic acids.

  6. Heralding efficiency and correlated-mode coupling of near-IR fiber-coupled photon pairs

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

    Dixon, P. Ben; Rosenberg, Danna; Stelmakh, Veronika

    We report on a systematic experimental study of heralding efficiency and generation rate of telecom-band infrared photon pairs generated by spontaneous parametric down-conversion and coupled to single mode optical fibers. We define the correlated-mode coupling efficiency--an inherent source efficiency--and explain its relation to heralding efficiency. For our experiment, we developed a reconfigurable computer controlled pump-beam and collection-mode optical apparatus which we used to measure the generation rate and correlated-mode coupling efficiency. The use of low-noise, high-efficiency superconducting-nanowire single-photon-detectors in this setup allowed us to explore focus configurations with low overall photon flux. The measured data agree well with theory andmore » we demonstrated a correlated-mode coupling efficiency of 97%±2%, which is the highest efficiency yet achieved for this type of system. These results confirm theoretical treatments and demonstrate that very high overall heralding efficiencies can, in principle, be achieved in quantum optical systems. We expect that these results and techniques will be widely incorporated into future systems that require, or benefit from, a high heralding efficiency.« less

  7. Heralding efficiency and correlated-mode coupling of near-IR fiber-coupled photon pairs

    DOE PAGES

    Dixon, P. Ben; Rosenberg, Danna; Stelmakh, Veronika; ...

    2014-10-06

    We report on a systematic experimental study of heralding efficiency and generation rate of telecom-band infrared photon pairs generated by spontaneous parametric down-conversion and coupled to single mode optical fibers. We define the correlated-mode coupling efficiency--an inherent source efficiency--and explain its relation to heralding efficiency. For our experiment, we developed a reconfigurable computer controlled pump-beam and collection-mode optical apparatus which we used to measure the generation rate and correlated-mode coupling efficiency. The use of low-noise, high-efficiency superconducting-nanowire single-photon-detectors in this setup allowed us to explore focus configurations with low overall photon flux. The measured data agree well with theory andmore » we demonstrated a correlated-mode coupling efficiency of 97%±2%, which is the highest efficiency yet achieved for this type of system. These results confirm theoretical treatments and demonstrate that very high overall heralding efficiencies can, in principle, be achieved in quantum optical systems. We expect that these results and techniques will be widely incorporated into future systems that require, or benefit from, a high heralding efficiency.« less

  8. A novel integration system of magnetically immobilized cells and a pair of graphite plate-stainless iron mesh electrodes for the bioremediation of coking wastewater.

    PubMed

    Jiang, Bei; Tan, Liang; Ning, Shuxiang; Shi, Shengnan

    2016-09-01

    Magnetically immobilized cells of Comamonas sp. JB coupling with electrode reaction was developed to enhance the treatment efficiency of coking wastewater containing phenol, carbazole (CA), dibenzofuran (DBF), and dibenzothiophene (DBT). The pair of graphite plate-stainless iron mesh electrodes was chosen as the most suitable electrodes. Magnetically immobilized cells coupling with graphite plate-stainless iron mesh electrodes (coupling system) exhibited high degradation activity for all the compounds, which were significantly higher than the sum by single magnetically immobilized cells and electrode reaction at the optimal voltage. Recycling experiments demonstrated that the degradation activity of coupling system increased gradually during eight recycles, indicating that there was a coupling effect between the biodegradation and electrode reaction. Phenol hydroxylase and qPCR assays confirmed that appropriate electrical stimulation could improve phenol hydroxylase activity and promote cells growth. Toxicity assessment suggested the treatment of the coking wastewater by coupling system led to less toxicity than untreated wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Controlled finite momentum pairing and spatially varying order parameter in proximitized HgTe quantum wells

    NASA Astrophysics Data System (ADS)

    Hart, Sean; Ren, Hechen; Kosowsky, Michael; Ben-Shach, Gilad; Leubner, Philipp; Bruene, Christoph; Buhmann, Hartmut; Molenkamp, Laurens; Halperin, Bertrand; Yacoby, Amir

    Conventional s-wave superconductivity arises from singlet pairing of electrons with opposite Fermi momenta, forming Cooper pairs with zero net momentum. Recent studies have focused on coupling s-wave superconductors to systems with an unusual configuration of electronic spin and momentum at the Fermi surface, where the nature of the paired state can be modified and the system may even undergo a topological phase transition. Here we present measurements on Josephson junctions based on HgTe quantum wells coupled to aluminum or niobium superconductors, and subject to a magnetic field in the plane of the quantum well. We observe that the in-plane magnetic field modulates the Fraunhofer interference pattern, and that this modulation depends both on electron density and on the direction of the in-plane field with respect to the junction. However, the orientation of the junction with respect to the underlying crystal lattice does not impact the measurements. These findings suggest that spin-orbit coupling plays a role in the observed behavior, and that measurements of Josephson junctions in the presence of an in-plane field can elucidate the Fermi surface properties of the weak link material. NSF DMR-1206016; STC Center for Integrated Quantum Materials under NSF Grant No. DMR-1231319; NSF GRFP under Grant DGE1144152, Microsoft Corporation Project Q.

  10. What correlation effects are covered by density functional theory?

    NASA Astrophysics Data System (ADS)

    He, Yuan; Grafenstein, Jurgen; Kraka, Elfi; Cremer, Dieter

    The electron density distribution rho(r) generated by a DFT calculation was systematically studied by comparison with a series of reference densities obtained by wavefunction theory (WFT) methods that cover typical electron correlation effects. As a sensitive indicator for correlation effects the dipole moment of the CO molecule was used. The analysis reveals that typical LDA and GGA exchange functionals already simulate effects that are actually reminiscent of pair and three-electron correlation effects covered by MP2, MP4, and CCSD(T) in WFT. Correlation functionals contract the density towards the bond and the valence region thus taking negative charge out of the van der Waals region. It is shown that these improvements are relevant for the description of van der Waals interactions. Similar to certain correlated single-determinant WFT methods, BLYP and other GGA functionals underestimate ionic terms needed for a correct description of polar bonds. This is compensated for in hybrid functionals by mixing in HF exchange. The balanced mixing of local and non-local exchange and correlation effects leads to the correct description of polar bonds as in the B3LYP description of the CO molecule. The density obtained with B3LYP is closer to CCSD and CCSD(T) than to MP2 or MP4, which indicates that the B3LYP hybrid functional mimics those pair and three-electron correlation effects, which in WFT are only covered by coupled cluster methods.

  11. Non-invasive determination of external forces in vortex-pair-cylinder interactions

    NASA Astrophysics Data System (ADS)

    Hartmann, D.; Schröder, W.; Shashikanth, B. N.

    2012-06-01

    Expressions for the conserved linear and angular momenta of a dynamically coupled fluid + solid system are derived. Based on the knowledge of the flow velocity field, these expressions allow the determination of the external forces exerted on a body moving in the fluid such as, e.g., swimming fish. The verification of the derived conserved quantities is done numerically. The interaction of a vortex pair with a circular cylinder in various configurations of motions representing a generic test case for a dynamically coupled fluid + solid system is investigated in a weakly compressible Navier-Stokes setting using a Cartesian cut-cell method, i.e., the moving circular cylinder is represented by cut cells on a moving mesh. The objectives of this study are twofold. The first objective is to show the robustness of the derived expressions for the conserved linear and angular momenta with respect to bounded and discrete data sets. The second objective is to study the coupled dynamics of the vortex pair and a neutrally buoyant cylinder free to move in response to the fluid stresses exerted on its surface. A comparison of the vortex-body interaction with the case of a fixed circular cylinder evidences significant differences in the vortex dynamics. When the cylinder is fixed strong secondary vorticity is generated resulting in a repeating process between the primary vortex pair and the cylinder. In the neutrally buoyant cylinder case, a stable structure consisting of the primary vortex pair and secondary vorticity shear layers stays attached to the moving cylinder. In addition to these fundamental cases, the vortex-pair-cylinder interaction is studied for locomotion at constant speed and locomotion at constant thrust. It is shown that a similar vortex structure like in the neutrally buoyant cylinder case is obtained when the cylinder moves away from the approaching vortex pair at a constant speed smaller than the vortex pair translational velocity. Finally, the idealized symmetric settings are complemented by an asymmetric interaction of a vortex pair and a cylinder. This case is discussed for a fixed and a neutrally buoyant cylinder to show the validity of the derived relations for multi-dimensional body dynamics.

  12. Prima facie evidence against spin-two Higgs impostors

    NASA Astrophysics Data System (ADS)

    Ellis, John; Sanz, Verónica; You, Tevong

    2013-10-01

    The new particle X recently discovered by the ATLAS and CMS Collaborations is widely expected to have spin zero, but this remains to be determined. The leading alternative is that X has spin two, presumably with graviton-like couplings. We show that measurements of the X particle to pairs of vector bosons constrain such scenarios. In particular, a graviton-like Higgs impostor in scenarios with a warped extra dimension of AdS type is prima facie excluded, principally because they predict too small a ratio between the X couplings to WW and ZZ, compared with that to photons. The data also disfavour universal couplings to pairs of photons and gluons, which would be predicted in a large class of graviton-like models.

  13. 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxyl as a model organic redox active compound for nonaqueous flow batteries

    NASA Astrophysics Data System (ADS)

    Milshtein, Jarrod D.; Barton, John L.; Darling, Robert M.; Brushett, Fikile R.

    2016-09-01

    Nonaqueous redox flow batteries (NAqRFBs) that utilize redox active organic molecules are an emerging energy storage concept with the possibility of meeting grid storage requirements. Sporadic and uneven advances in molecular discovery and development, however, have stymied efforts to quantify the performance characteristics of nonaqueous redox electrolytes and flow cells. A need exists for archetypal redox couples, with well-defined electrochemical properties, high solubility in relevant electrolytes, and broad availability, to serve as probe molecules. This work investigates the 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxyl (AcNH-TEMPO) redox pair for such an application. We report the physicochemical and electrochemical properties of the reduced and oxidized compounds at dilute concentrations for electroanalysis, as well as moderate-to-high concentrations for RFB applications. Changes in conductivity, viscosity, and UV-vis absorbance as a function of state-of-charge are quantified. Cyclic voltammetry investigates the redox potential, reversibility, and diffusion coefficients of dilute solutions, while symmetric flow cell cycling determines the stability of the AcNH-TEMPO redox pair over long experiment times. Finally, single electrolyte flow cell studies demonstrate the utility of this redox couple as a platform chemistry for benchmarking NAqRFB performance.

  14. Discrete symmetries and the propagator approach to coupled fermions in Quantum Field Theory. Generalities: The case of a single fermion-antifermion pair

    NASA Astrophysics Data System (ADS)

    Duret, Q.; Machet, B.

    2010-10-01

    Starting from Wigner's symmetry representation theorem, we give a general account of discrete symmetries (parity P, charge conjugation C, time-reversal T), focusing on fermions in Quantum Field Theory. We provide the rules of transformation of Weyl spinors, both at the classical level (grassmanian wave functions) and quantum level (operators). Making use of Wightman's definition of invariance, we outline ambiguities linked to the notion of classical fermionic Lagrangian. We then present the general constraints cast by these transformations and their products on the propagator of the simplest among coupled fermionic system, the one made with one fermion and its antifermion. Last, we put in correspondence the propagation of C eigenstates (Majorana fermions) and the criteria cast on their propagator by C and CP invariance.

  15. Dynamical Bayesian inference of time-evolving interactions: from a pair of coupled oscillators to networks of oscillators.

    PubMed

    Duggento, Andrea; Stankovski, Tomislav; McClintock, Peter V E; Stefanovska, Aneta

    2012-12-01

    Living systems have time-evolving interactions that, until recently, could not be identified accurately from recorded time series in the presence of noise. Stankovski et al. [Phys. Rev. Lett. 109, 024101 (2012)] introduced a method based on dynamical Bayesian inference that facilitates the simultaneous detection of time-varying synchronization, directionality of influence, and coupling functions. It can distinguish unsynchronized dynamics from noise-induced phase slips. The method is based on phase dynamics, with Bayesian inference of the time-evolving parameters being achieved by shaping the prior densities to incorporate knowledge of previous samples. We now present the method in detail using numerically generated data, data from an analog electronic circuit, and cardiorespiratory data. We also generalize the method to encompass networks of interacting oscillators and thus demonstrate its applicability to small-scale networks.

  16. Influence of Magnetic Ordering between Cr Adatoms on the Yu-Shiba-Rusinov States of the β -Bi2Pd Superconductor

    NASA Astrophysics Data System (ADS)

    Choi, Deung-Jang; Fernández, Carlos García; Herrera, Edwin; Rubio-Verdú, Carmen; Ugeda, Miguel M.; Guillamón, Isabel; Suderow, Hermann; Pascual, José Ignacio; Lorente, Nicolás

    2018-04-01

    We show that the magnetic ordering of coupled atomic dimers on a superconductor is revealed by their intragap spectral features. Chromium atoms on the superconductor β -Bi2Pd surface display Yu-Shiba-Rusinov bound states, detected as pairs of intragap excitations in tunneling spectra. By means of atomic manipulation with a scanning tunneling microscope's tip, we form Cr dimers with different arrangements and find that their intragap features appear either shifted or split with respect to single atoms. These spectral variations are associated with the magnetic coupling, ferromagnetic or antiferromagnetic, of the dimer, as confirmed by density functional theory simulations. The striking qualitative differences between the observed tunneling spectra prove that intragap Shiba states are extremely sensitive to the magnetic ordering on the atomic scale.

  17. Structure and energetics of Cr(CO)6 and Cr(CO)5

    NASA Technical Reports Server (NTRS)

    Barnes, Leslie A.; Liu, Bowen; Lindh, Roland

    1993-01-01

    The geometric structures and energetics of Cr(CO)6 and Cr(CO)5 are determined at the modified coupled-pair functional, single and double excitation coupled-cluster (CCSD), and CCSD(T) levels of theory. For Cr(CO)6, the structure and force constants for the totally symmetric representation are in good agreement with experimental data once basis set constants are taken into account. In the largest basis set at the CCSD(T) level of theory, the total binding energy of CR(CO)6 is estimated at around 140 kcal/mol, or about 86 percent of the experimental value. In contrast, the first bond energy of Cr(CO)6 is very well described at the CCSD(T) level of theory, with the best estimated value of 38 kcal/mol being within the experimental uncertainty.

  18. Ab initio quantum chemical calculation of electron transfer matrix elements for large molecules

    NASA Astrophysics Data System (ADS)

    Zhang, Linda Yu; Friesner, Richard A.; Murphy, Robert B.

    1997-07-01

    Using a diabatic state formalism and pseudospectral numerical methods, we have developed an efficient ab initio quantum chemical approach to the calculation of electron transfer matrix elements for large molecules. The theory is developed at the Hartree-Fock level and validated by comparison with results in the literature for small systems. As an example of the power of the method, we calculate the electronic coupling between two bacteriochlorophyll molecules in various intermolecular geometries. Only a single self-consistent field (SCF) calculation on each of the monomers is needed to generate coupling matrix elements for all of the molecular pairs. The largest calculations performed, utilizing 1778 basis functions, required ˜14 h on an IBM 390 workstation. This is considerably less cpu time than would be necessitated with a supermolecule adiabatic state calculation and a conventional electronic structure code.

  19. Combinations of coupled cluster, density functionals, and the random phase approximation for describing static and dynamic correlation, and van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Garza, Alejandro J.; Bulik, Ireneusz W.; Alencar, Ana G. Sousa; Sun, Jianwei; Perdew, John P.; Scuseria, Gustavo E.

    2016-04-01

    Contrary to standard coupled cluster doubles (CCD) and Brueckner doubles (BD), singlet-paired analogues of CCD and BD (denoted here as CCD0 and BD0) do not break down when static correlation is present, but neglect substantial amounts of dynamic correlation. In fact, CCD0 and BD0 do not account for any contributions from multielectron excitations involving only same-spin electrons at all. We exploit this feature to add - without introducing double counting, self-interaction, or increase in cost - the missing correlation to these methods via meta-GGA (generalised gradient approximation) density functionals (Tao-Perdew-Staroverov-Scuseria and strongly constrained and appropriately normed). Furthermore, we improve upon these CCD0+DFT blends by invoking range separation: the short- and long-range correlations absent in CCD0/BD0 are evaluated with density functional theory and the direct random phase approximation, respectively. This corrects the description of long-range van der Waals forces. Comprehensive benchmarking shows that the combinations presented here are very accurate for weakly correlated systems, while also providing a reasonable description of strongly correlated problems without resorting to symmetry breaking.

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

    Degrassi, G.; Giardino, P. P.; Maltoni, F.

    Here, we propose a method to determine the trilinear Higgs self coupling that is alternative to the direct measurement of Higgs pair production total cross sections and differential distributions. Furthermore, the method relies on the effects that electroweak loops featuring an anomalous trilinear coupling would imprint on single Higgs production at the LHC. We first calculate these contributions to all the phenomenologically relevant Higgs production (ggF, VBF, WH, ZH, tmore » $$\\bar{t}$$ ) and decay (γγ,WW*/ZZ*→ 4f, b$$\\bar{b}$$,ττ) modes at the LHC and then estimate the sensitivity to the trilinear coupling via a one-parameter fit to the single Higgs measurements at the LHC 8 TeV. We also found that the bounds on the self coupling are already competitive with those from Higgs pair production and will be further improved in the current and next LHC runs.« less

  1. Multiple Pairwise Analysis of Non-homologous Centromere Coupling Reveals Preferential Chromosome Size-Dependent Interactions and a Role for Bouquet Formation in Establishing the Interaction Pattern

    PubMed Central

    Lefrançois, Philippe; Rockmill, Beth; Xie, Pingxing; Roeder, G. Shirleen; Snyder, Michael

    2016-01-01

    During meiosis, chromosomes undergo a homology search in order to locate their homolog to form stable pairs and exchange genetic material. Early in prophase, chromosomes associate in mostly non-homologous pairs, tethered only at their centromeres. This phenomenon, conserved through higher eukaryotes, is termed centromere coupling in budding yeast. Both initiation of recombination and the presence of homologs are dispensable for centromere coupling (occurring in spo11 mutants and haploids induced to undergo meiosis) but the presence of the synaptonemal complex (SC) protein Zip1 is required. The nature and mechanism of coupling have yet to be elucidated. Here we present the first pairwise analysis of centromere coupling in an effort to uncover underlying rules that may exist within these non-homologous interactions. We designed a novel chromosome conformation capture (3C)-based assay to detect all possible interactions between non-homologous yeast centromeres during early meiosis. Using this variant of 3C-qPCR, we found a size-dependent interaction pattern, in which chromosomes assort preferentially with chromosomes of similar sizes, in haploid and diploid spo11 cells, but not in a coupling-defective mutant (spo11 zip1 haploid and diploid yeast). This pattern is also observed in wild-type diploids early in meiosis but disappears as meiosis progresses and homologous chromosomes pair. We found no evidence to support the notion that ancestral centromere homology plays a role in pattern establishment in S. cerevisiae post-genome duplication. Moreover, we found a role for the meiotic bouquet in establishing the size dependence of centromere coupling, as abolishing bouquet (using the bouquet-defective spo11 ndj1 mutant) reduces it. Coupling in spo11 ndj1 rather follows telomere clustering preferences. We propose that a chromosome size preference for centromere coupling helps establish efficient homolog recognition. PMID:27768699

  2. Hybrid density functional study of organic magnetic crystals: bi-metallic CrIII cyanides and rhombohedral C60

    NASA Astrophysics Data System (ADS)

    Chan, J. A.; Montanari, B.; Chan, W. L.; Harrison, N. M.

    Periodic hybrid-exchange density functional theory calculations have been used to investigate the magnetic properties of two classes of organic magnets, namely the bi-metallic CrIII cyanides and the polymerized rhombohedral C60 fullerenes (Rh-C60). For the systems KMII[CrIII(CN)6] with M II=V, Mn, Ni and CrIII[CrIII(CN)6], the magnetic ordering energies, Mulliken populations, and spin density plots are reported for the optimized geometries. The qualitative nature of the magnetic coupling mechanism is consistent with that observed in previous unrestricted Hartree-Fock calculations, but the coupling energies computed here are significantly higher. The increased coupling is found to be a result of both changes in the geometry and the electronic structure resulting from the more reliable treatment of electronic exchange and correlation effects. The existence of long-range coupling between local spin moments is investigated in three different defective Rh-C60 structures: (i) a previously proposed prototype structure, where an atom is removed from the C60 cage; (ii) a related structure in which vacancies in nearby cages are brought closer together in pairs; and (iii) a structure where the intra-fullerene bond between the two inter-fullerene bonds is broken spontaneously after applying isotropic pressure to one layer of the Rh-C60 structure. All of these structures are characterized by low flat spin polarized bands at the Fermi edge and localized spin moments around the defects, but no evidence of long-range magnetic coupling is found.

  3. Changes in corticocortical and corticohippocampal network during absence seizures in WAG/Rij rats revealed with time varying Granger causality.

    PubMed

    Sysoeva, Marina V; Vinogradova, Lyudmila V; Kuznetsova, Galina D; Sysoev, Ilya V; van Rijn, Clementina M

    2016-11-01

    Spike-and-wave discharges (SWDs) recorded in the cortical EEGs of WAG/Rij rats are the hallmark for absence epilepsy in this model. Although this type of epilepsy was long regarded as a form of primary generalized epilepsy, it is now recognized that there is an initiation zone - the perioral region of the somatosensory cortex. However, networks involved in spreading the seizure are not yet fully known. Previously, the dynamics of coupling between different layers of the perioral cortical region and between these zones and different thalamic nuclei was studied in time windows around the SWDs, using nonlinear Granger causality. The aim of the present study was to investigate, using the same method, the coupling dynamics between different regions of the cortex and between these regions and the hippocampus. Local field potentials were recorded in the frontal, parietal, and occipital cortices and in the hippocampus of 19 WAG/Rij rats. To detect changes in coupling reliably in a short time window, in order to provide a good temporal resolution, the innovative adapted time varying nonlinear Granger causality method was used. Mutual information function was calculated in addition to validate outcomes. Results of both approaches were tested for significance. The SWD initiation process was revealed as an increase in intracortical interactions starting from 3.5s before the onset of electrographic seizure. The earliest preictal increase in coupling was directed from the frontal cortex to the parietal cortex. Then, the coupling became bidirectional, followed by the involvement of the occipital cortex (1.5s before SWD onset). There was no driving from any cortical region to hippocampus, but a slight increase in coupling from hippocampus to the frontoparietal cortex was observed just before SWD onset. After SWD onset, an abrupt drop in coupling in all studied pairs was observed. In most of the pairs, the decoupling rapidly disappeared, but driving force from hippocampus and occipital cortex to the frontoparietal cortex was reduced until the SWD termination. Involvement of multiple cortical regions in SWD initiation shows the fundamental role of corticocortical feedback loops, forming coupling architecture and triggering the generalized seizure. The results add to the ultimate aim to construct a complete picture of brain interactions preceding and accompanying absence seizures in rats. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Theoretical Study of the Electric Dipole Moment Function of the CIO Molecule

    NASA Technical Reports Server (NTRS)

    Pettersson, Lars G. M.; Langhoff, Stephen R.; Chong, Delano P.

    1986-01-01

    The potential energy function and electric dipole moment function (EDMF) are computed for CIO Chi(sup 2)Pi using several different techniques to include electron correlation. The EDMF is used to compute Einstein coefficients, vibrational lifetimes, and dipole moments in higher vibrational levels. Remaining questions concerning the position of the maximum of the EDMF may be resolved through experimental measurement of dipole moments of higher vibrational levels. The band strength of the 1-0 fundamental transition is computed to be 12 +/- 2 /sq cm atm in good agreement with three experimental values, but larger than a recent value of 5 /sq cm atm determined from infrared heterodyne spectroscopy. The theoretical methods used include SCF, CASSCF, multireference singles plus doubles configuration interaction (MRCI) and contracted CI, coupled pair functional (CPF), and a modified version of the CPF method. The results obtained using the different methods are critically compared.

  5. Effects of self-coupling and asymmetric output on metastable dynamical transient firing patterns in arrays of neurons with bidirectional inhibitory coupling.

    PubMed

    Horikawa, Yo

    2016-04-01

    Metastable dynamical transient patterns in arrays of bidirectionally coupled neurons with self-coupling and asymmetric output were studied. First, an array of asymmetric sigmoidal neurons with symmetric inhibitory bidirectional coupling and self-coupling was considered and the bifurcations of its steady solutions were shown. Metastable dynamical transient spatially nonuniform states existed in the presence of a pair of spatially symmetric stable solutions as well as unstable spatially nonuniform solutions in a restricted range of the output gain of a neuron. The duration of the transients increased exponentially with the number of neurons up to the maximum number at which the spatially nonuniform steady solutions were stabilized. The range of the output gain for which they existed reduced as asymmetry in a sigmoidal output function of a neuron increased, while the existence range expanded as the strength of inhibitory self-coupling increased. Next, arrays of spiking neuron models with slow synaptic inhibitory bidirectional coupling and self-coupling were considered with computer simulation. In an array of Class 1 Hindmarsh-Rose type models, in which each neuron showed a graded firing rate, metastable dynamical transient firing patterns were observed in the presence of inhibitory self-coupling. This agreed with the condition for the existence of metastable dynamical transients in an array of sigmoidal neurons. In an array of Class 2 Bonhoeffer-van der Pol models, in which each neuron had a clear threshold between firing and resting, long-lasting transient firing patterns with bursting and irregular motion were observed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Effective theory of exotic superconductivity in LaAlO3/SrTiO3 interfaces

    NASA Astrophysics Data System (ADS)

    Esmailzadeh, Haniyeh; Moghaddam, Ali G.

    2018-05-01

    Motivated by experimental and theoretical works about superconductivity at the oxide interfaces, we provide a simple model for possible unconventional pairings inside the exotic two-dimensional electron gas formed in heterostructures of SrTiO3 and LaAlO3. At the low energy limit, the electron gas at the interfaces is usually modeled with an effective three band model considering of 3d t2g orbitals which are slightly coupled by atomic spin-orbit couplings (SOC). Considering direct superconducting pairing in two higher delocalized bands and by exploiting a perturbative scheme based on canonical transformation, we derive the effective pairing amplitudes with possibly exotic nature inside the localized dxy band as well as various inter-band pairing components. In particular we show that equal-spin triplet pairings are possible between the band dxy and any of other dxz and dyz bands. In addition weaker effective pairings take place inside the localized band itself and between delocalized dxz and dyz bands with singlet and opposite-spin triplet characters. These unconventional effective pairings are indeed mediated by SOC-induced higher order virtual transitions between the bands and particularly into the localized band. Our model suggest that unconventional effective superconductivity is possible at oxide interfaces, simply, due to the special band structure and important role of atomic SOC and perhaps other magnetic effects present at these heterostructures.

  7. BCS-Bose model of exotic superconductors: Generalized coherence length

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

    Casas, M.; Getino, J.M.; de Llano, M.

    1994-12-01

    Analytic expressions are derived for the root-mean-square (rms) radius of a pair of fermions in a BCS many-fermion state in one, two, and three dimensions, in terms of the BCS gap energy and the associated chemical potential. These expressions are valid for any coupling strength of [ital any] pair interaction model implying a momentum-independent gap energy. The latter holds, e.g., for an attractive [delta] pair potential examined in the one-dimensional (1D) case (whose [ital N]-fermion ground state can be determined exactly) or for the BCS (electron-phonon) model interaction in any dimension. Weak-coupling and/or high-density limits for the rms radius aremore » identical in 1D, 2D, and 3D, and reduce to the familiar well-known Pippard result to within a factor of order unity. In contrast, strong-coupling and/or low-density limits coincide in 1D and 3D, but differ by a factor of order unity in the 2D limit, and in each case are essentially the size of a single, isolated pair. The 1D [delta] interaction McGuire-Yang-Gaudin many-fermion model is studied in detail. The interaction renormalization scheme of Miyake and of Randeria, Duan, and Shieh, and the BCS interaction model, both in 2D, are employed to analyze cuprate superconductor empirical results. Reasonable agreement between theoretical rms radii with experimental coherence lengths suggests that cuprates can be described moderately well as [ital weakly] [ital coupled] superconductors within the BCS-Bose formalism.« less

  8. ChIP-seq and ChIP-exo profiling of Pol II, H2A.Z, and H3K4me3 in human K562 cells.

    PubMed

    Mchaourab, Zenab F; Perreault, Andrea A; Venters, Bryan J

    2018-03-06

    The human K562 chronic myeloid leukemia cell line has long served as an experimental paradigm for functional genomic studies. To systematically and functionally annotate the human genome, the ENCODE consortium generated hundreds of functional genomic data sets, such as chromatin immunoprecipitation coupled to sequencing (ChIP-seq). While ChIP-seq analyses have provided tremendous insights into gene regulation, spatiotemporal insights were limited by a resolution of several hundred base pairs. ChIP-exonuclease (ChIP-exo) is a refined version of ChIP-seq that overcomes this limitation by providing higher precision mapping of protein-DNA interactions. To study the interplay of transcription initiation and chromatin, we profiled the genome-wide locations for RNA polymerase II (Pol II), the histone variant H2A.Z, and the histone modification H3K4me3 using ChIP-seq and ChIP-exo. In this Data Descriptor, we present detailed information on parallel experimental design, data generation, quality control analysis, and data validation. We discuss how these data lay the foundation for future analysis to understand the relationship between the occupancy of Pol II and nucleosome positions at near base pair resolution.

  9. Electron Correlation from the Adiabatic Connection for Multireference Wave Functions

    NASA Astrophysics Data System (ADS)

    Pernal, Katarzyna

    2018-01-01

    An adiabatic connection (AC) formula for the electron correlation energy is derived for a broad class of multireference wave functions. The AC expression recovers dynamic correlation energy and assures a balanced treatment of the correlation energy. Coupling the AC formalism with the extended random phase approximation allows one to find the correlation energy only from reference one- and two-electron reduced density matrices. If the generalized valence bond perfect pairing model is employed a simple closed-form expression for the approximate AC formula is obtained. This results in the overall M5 scaling of the computation cost making the method one of the most efficient multireference approaches accounting for dynamic electron correlation also for the strongly correlated systems.

  10. Calculation of the Full Scattering Amplitude without Partial Wave Decomposition II: Inclusion of Exchange

    NASA Technical Reports Server (NTRS)

    Shertzer, Janine; Temkin, A.

    2003-01-01

    As is well known, the full scattering amplitude can be expressed as an integral involving the complete scattering wave function. We have shown that the integral can be simplified and used in a practical way. Initial application to electron-hydrogen scattering without exchange was highly successful. The Schrodinger equation (SE), which can be reduced to a 2d partial differential equation (pde), was solved using the finite element method. We have now included exchange by solving the resultant SE, in the static exchange approximation, which is reducible to a pair of coupled pde's. The resultant scattering amplitudes, both singlet and triplet, calculated as a function of energy are in excellent agreement with converged partial wave results.

  11. Tunable semiconductor lasers

    NASA Technical Reports Server (NTRS)

    Taghavi-Larigani, Shervin (Inventor); Vanzyl, Jakob J. (Inventor); Yariv, Amnon (Inventor)

    2006-01-01

    Tunable semiconductor lasers are disclosed requiring minimized coupling regions. Multiple laser embodiments employ ring resonators or ring resonator pairs using only a single coupling region with the gain medium are detailed. Tuning can be performed by changing the phase of the coupling coefficient between the gain medium and a ring resonator of the laser. Another embodiment provides a tunable laser including two Mach-Zehnder interferometers in series and a reflector coupled to a gain medium.

  12. Helix coupling

    DOEpatents

    Ginell, W.S.

    1982-03-17

    A coupling for connecting helix members in series, which consists of a pair of U-shaped elements, one of which is attached to each helix end with the U sections of the elements interlocked. The coupling is particularly beneficial for interconnecting helical Nitinol elements utilized in thermal actuators or engines. Each coupling half is attached to the associated helix at two points, thereby providing axial load while being easily removed from the helix, and reusable.

  13. Helix coupling

    DOEpatents

    Ginell, William S.

    1989-04-25

    A coupling for connecting helix members in series, which consists of a pair of U-shaped elements, one of which is attached to each helix end with the "U" sections of the elements interlocked. The coupling is particularly beneficial for interconnecting helical Nitinol elements utilized in thermal actuators or engines. Each coupling half is attached to the associated helix at two points, thereby providing axial load while being easily removed from the helix, and reusable.

  14. Solid State Photochemical Generation of Triplet Phenoxy-Phenoxy Radical Pairs

    DTIC Science & Technology

    1990-04-01

    of diphenyl oxalate . Tert-butylated bis-aryloxalat s show good radical pair stability, with triplet ESR signals surviving days at room temperature in...between the geminate phenoxyl radicals. The comparable breadth of the spectra for diphenyl carbonate and the oxalates implies a similar interaction strength...ferromagnetic coupling that may be achieved in geminate pairs generated from a diphenyl oxalate vs. a diphenyl carbonate. In addition, we see similar

  15. Imino proton exchange and base-pair kinetics in the AMP-RNA aptamer complex.

    PubMed

    Nonin, S; Jiang, F; Patel, D J

    1997-05-02

    We report on the dynamics of base-pair opening in the ATP-binding asymmetric internal loop and flanking base-pairs of the AMP-RNA aptamer complex by monitoring the exchange characteristics of the extremely well resolved imino protons in the NMR spectrum of the complex. The kinetics of imino proton exchange as a function of basic pH or added ammonia catalyst are used to measure the apparent base-pair dissociation constants and lifetimes of Watson-Crick and mismatched base-pairs, as well as the solvent accessibility of the unpaired imino protons in the complex. The exchange characteristics of the imino protons identify the existence of four additional hydrogen bonds stabilizing the conformation of the asymmetric ATP-binding internal loop that were not detected by NOEs and coupling constants alone, but are readily accommodated in the previously reported solution structure of the AMP-RNA aptamer complex published from our laboratory. The hydrogen exchange kinetics of the non-Watson-Crick pairs in the asymmetric internal loop of the AMP-RNA aptamer complex have been characterized and yield apparent dissociation constants (alphaKd) that range from 10(-2) to 10(-7). Surprisingly, three of these alphaKd values are amongst the lowest measured for all base-pairs in the AMP-RNA aptamer complex. Comparative studies of hydrogen exchange of the imino protons in the free RNA aptamer and the AMP-RNA aptamer complex establish that complexation stabilizes not only the bases within the ATP-binding asymmetric internal loop, but also the flanking stem base-pairs (two pairs on either side) of the binding site. We also outline some preliminary results related to the exchange properties of a sugar 2'-hydroxyl proton of a guanosine residue involved in a novel hydrogen bond that has been shown to contribute to the immobilization of the bound AMP by the RNA aptamer, and whose resonance is narrow and downfield shifted in the spectrum.

  16. Vortex coupling in trailing vortex-wing interactions

    NASA Astrophysics Data System (ADS)

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

    2018-03-01

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

  17. Feedback stabilization of resistive wall modes in a reversed-field pinch

    NASA Astrophysics Data System (ADS)

    Brunsell, P. R.; Yadikin, D.; Gregoratto, D.; Paccagnella, R.; Liu, Y. Q.; Cecconello, M.; Drake, J. R.; Manduchi, G.; Marchiori, G.

    2005-09-01

    An array of saddle coils having Nc=16 equally spaced positions along the toroidal direction has been installed for feedback control of resistive wall modes (RWMs) on the EXTRAP T2R reversed-field pinch [P. R. Brunsell, H. Bergsaker, M. Cecconello et al., Plasma Phys. Controlled Fusion 43, 1457 (2001)]. Using feedback, multiple nonresonant RWMs are simultaneously suppressed for three to four wall times. Feedback stabilization of RWMs results in a significant prolongation of the discharge duration. This is linked to a better sustainment of the plasma and tearing mode toroidal rotation with feedback. Due to the limited number of coils in the toroidal direction, pairs of modes with toroidal mode numbers n ,n' that fulfill the condition ∣n-n'∣=Nc are coupled by the feedback action from the discrete coil array. With only one unstable mode in a pair of coupled modes, the suppression of the unstable mode is successful. If two modes are unstable in a coupled pair, two possibilities exist: partial suppression of both modes or, alternatively, complete stabilization of one target mode while the other is left unstable.

  18. Statistical exchange-coupling errors and the practicality of scalable silicon donor qubits

    NASA Astrophysics Data System (ADS)

    Song, Yang; Das Sarma, S.

    2016-12-01

    Recent experimental efforts have led to considerable interest in donor-based localized electron spins in Si as viable qubits for a scalable silicon quantum computer. With the use of isotopically purified 28Si and the realization of extremely long spin coherence time in single-donor electrons, the recent experimental focus is on two-coupled donors with the eventual goal of a scaled-up quantum circuit. Motivated by this development, we simulate the statistical distribution of the exchange coupling J between a pair of donors under realistic donor placement straggles, and quantify the errors relative to the intended J value. With J values in a broad range of donor-pair separation ( 5 <|R |<60 nm), we work out various cases systematically, for a target donor separation R0 along the [001], [110] and [111] Si crystallographic directions, with |R0|=10 ,20 or 30 nm and standard deviation σR=1 ,2 ,5 or 10 nm. Our extensive theoretical results demonstrate the great challenge for a prescribed J gate even with just a donor pair, a first step for any scalable Si-donor-based quantum computer.

  19. Numerical analysis of spin-orbit-coupled one-dimensional Fermi gas in a magnetic field

    NASA Astrophysics Data System (ADS)

    Chan, Y. H.

    2015-06-01

    Based on the density-matrix renormalization group and the infinite time-evolving block decimation methods we study the interacting spin-orbit-coupled 1D Fermi gas in a transverse magnetic field. We find that the system with an attractive interaction can have a polarized insulator phase, a superconducting (SC) phase, a Luther-Emery (LE) phase, and a band insulator phase as we vary the chemical potential and the strength of the magnetic field. Spin-orbit coupling (SOC) enhances the triplet pairing order at zero momentum in both the SC and the LE phase, which leads to an algebraically decaying correlation with the same exponent as that of the singlet pairing one. In contrast to the Fulde-Ferrell-Larkin-Ovchinnikov phase found in the spin imbalanced system without SOC, pairings at finite momentum in these two phases have larger exponents hence do not dictate the long-range behavior. We also test for the presence of Majorana fermions in this system. Unlike results from the mean-field study, we do not find positive evidence of Majorana fermions.

  20. Superconductivity-induced magnetization depletion in a ferromagnet through an insulator in a ferromagnet-insulator-superconductor hybrid oxide heterostructure.

    PubMed

    Prajapat, C L; Singh, Surendra; Paul, Amitesh; Bhattacharya, D; Singh, M R; Mattauch, S; Ravikumar, G; Basu, S

    2016-05-21

    Coupling between superconducting and ferromagnetic states in hybrid oxide heterostructures is presently a topic of intense research. Such a coupling is due to the leakage of the Cooper pairs into the ferromagnet. However, tunneling of the Cooper pairs though an insulator was never considered plausible. Using depth sensitive polarized neutron reflectivity we demonstrate the coupling between superconductor and magnetic layers in epitaxial La2/3Ca1/3MnO3 (LCMO)/SrTiO3/YBa2Cu3O7-δ (YBCO) hybrid heterostructures, with SrTiO3 as an intervening oxide insulator layer between the ferromagnet and the superconductor. Measurements above and below the superconducting transition temperature (TSC) of YBCO demonstrate a large modulation of magnetization in the ferromagnetic layer below the TSC of YBCO in these heterostructures. This work highlights a unique tunneling phenomenon between the epitaxial layers of an oxide superconductor (YBCO) and a magnetic layer (LCMO) through an insulating layer. Our work would inspire further investigations on the fundamental aspect of a long range order of the triplet spin-pairing in hybrid structures.

  1. Magnetosphere dynamics during the 14 November 2012 storm inferred from TWINS, AMPERE, Van Allen Probes, and BATS-R-US-CRCM

    NASA Astrophysics Data System (ADS)

    Buzulukova, Natalia; Goldstein, Jerry; Fok, Mei-Ching; Glocer, Alex; Valek, Phil; McComas, David; Korth, Haje; Anderson, Brian

    2018-01-01

    During the 14 November 2012 geomagnetic storm, the Van Allen Probes spacecraft observed a number of sharp decreases (dropouts) in particle fluxes for ions and electrons of different energies. In this paper, we investigate the global magnetosphere dynamics and magnetosphere-ionosphere (M-I) coupling during the dropout events using multipoint measurements by Van Allen Probes, TWINS, and AMPERE together with the output of the two-way coupled global BATS-R-US-CRCM model. We find different behavior for two pairs of dropouts. For one pair, the same pattern was repeated: (1) weak nightside Region 1 and 2 Birkeland currents before and during the dropout; (2) intensification of Region 2 currents after the dropout; and (3) a particle injection detected by TWINS after the dropout. The model predicted similar behavior of Birkeland currents. TWINS low-altitude emissions demonstrated high variability during these intervals, indicating high geomagnetic activity in the near-Earth tail region. For the second pair of dropouts, the structure of both Birkeland currents and ENA emissions was relatively stable. The model also showed quasi-stationary behavior of Birkeland currents and simulated ENA emissions with gradual ring current buildup. We confirm that the first pair of dropouts was caused by large-scale motions of the OCB (open-closed boundary) during substorm activity. We show the new result that this OCB motion was associated with global changes in Birkeland (M-I coupling) currents and strong modulation of low-altitude ion precipitation. The second pair of dropouts is the result of smaller OCB disturbances not related to magnetospheric substorms. The local observations of the first pair of dropouts result from a global magnetospheric reconfiguration, which is manifested by ion injections and enhanced ion precipitation detected by TWINS and changes in the structure of Birkeland currents detected by AMPERE. This study demonstrates that multipoint measurements along with the global model results enable the reconstruction of a more complete system-level picture of the dropout events and provides insight into M-I coupling aspects that have not previously been investigated.

  2. Magnetosphere dynamics during the 14 November 2012 storm inferred from TWINS, AMPERE, Van Allen Probes, and BATS-R-US–CRCM

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

    Buzulukova, Natalia; Goldstein, Jerry; Fok, Mei-Ching

    During the 14 November 2012 geomagnetic storm, the Van Allen Probes spacecraft observed a number of sharp decreases ("dropouts") in particle fluxes for ions and electrons of different energies. In this paper, we investigate the global magnetosphere dynamics and magnetosphere–ionosphere (M–I) coupling during the dropout events using multipoint measurements by Van Allen Probes, TWINS, and AMPERE together with the output of the two-way coupled global BATS-R-US–CRCM model. We find different behavior for two pairs of dropouts. For one pair, the same pattern was repeated: (1) weak nightside Region 1 and 2 Birkeland currents before and during the dropout; (2) intensificationmore » of Region 2 currents after the dropout; and (3) a particle injection detected by TWINS after the dropout. The model predicted similar behavior of Birkeland currents. TWINS low-altitude emissions demonstrated high variability during these intervals, indicating high geomagnetic activity in the near-Earth tail region. For the second pair of dropouts, the structure of both Birkeland currents and ENA emissions was relatively stable. The model also showed quasi-stationary behavior of Birkeland currents and simulated ENA emissions with gradual ring current buildup. We confirm that the first pair of dropouts was caused by large-scale motions of the OCB (open–closed boundary) during substorm activity. We show the new result that this OCB motion was associated with global changes in Birkeland (M–I coupling) currents and strong modulation of low-altitude ion precipitation. The second pair of dropouts is the result of smaller OCB disturbances not related to magnetospheric substorms. The local observations of the first pair of dropouts result from a global magnetospheric reconfiguration, which is manifested by ion injections and enhanced ion precipitation detected by TWINS and changes in the structure of Birkeland currents detected by AMPERE. This study demonstrates that multipoint measurements along with the global model results enable the reconstruction of a more complete system-level picture of the dropout events and provides insight into M–I coupling aspects that have not previously been investigated.« less

  3. Magnetosphere Dynamics During the 14 November 2012 Storm Inferred from TWINS, AMPERE, Van Allen Probes, and BATS-R-US-CRCM

    NASA Technical Reports Server (NTRS)

    Buzulukova, Natalia; Goldstein, Jerry; Fok, Mei-Ching; Glocer, Alex; Valek, Phil; McComas, David; Korth, Haje; Anderson, Brian

    2018-01-01

    During the 14 November 2012 geomagnetic storm, the Van Allen Probes spacecraft observed a number of sharp decreases ('dropouts') in particle fluxes for ions and electrons of different energies. In this paper, we investigate the global magnetosphere dynamics and magnetosphere- ionosphere (M-I) coupling during the dropout events using multipoint measurements by Van Allen Probes, TWINS, and AMPERE together with the output of the two-way coupled global BATS-R-US-CRCM model. We find different behavior for two pairs of dropouts. For one pair, the same pattern was repeated: (1) weak nightside Region 1 and 2 Birkeland currents before and during the dropout; (2) intensification of Region 2 currents after the dropout; and (3) a particle injection detected by TWINS after the dropout. The model predicted similar behavior of Birkeland currents. TWINS low-altitude emissions demonstrated high variability during these intervals, indicating high geomagnetic activity in the near-Earth tail region. For the second pair of dropouts, the structure of both Birkeland currents and ENA emissions was relatively stable. The model also showed quasi-stationary behavior of Birkeland currents and simulated ENA emissions with gradual ring current buildup. We confirm that the first pair of dropouts was caused by large-scale motions of the OCB (open-closed boundary) during substorm activity. We show the new result that this OCB motion was associated with global changes in Birkeland (M-I coupling) currents and strong modulation of low-altitude ion precipitation. The second pair of dropouts is the result of smaller OCB disturbances not related to magnetospheric substorms. The local observations of the first pair of dropouts result from a global magnetospheric reconfiguration, which is manifested by ion injections and enhanced ion precipitation detected by TWINS and changes in the structure of Birkeland currents detected by AMPERE. This study demonstrates that multipoint measurements along with the global model results enable the reconstruction of a more complete system-level picture of the dropout events and provides insight into M-I coupling aspects that have not previously been investigated.

  4. Magnetosphere dynamics during the 14 November 2012 storm inferred from TWINS, AMPERE, Van Allen Probes, and BATS-R-US–CRCM

    DOE PAGES

    Buzulukova, Natalia; Goldstein, Jerry; Fok, Mei-Ching; ...

    2018-01-25

    During the 14 November 2012 geomagnetic storm, the Van Allen Probes spacecraft observed a number of sharp decreases ("dropouts") in particle fluxes for ions and electrons of different energies. In this paper, we investigate the global magnetosphere dynamics and magnetosphere–ionosphere (M–I) coupling during the dropout events using multipoint measurements by Van Allen Probes, TWINS, and AMPERE together with the output of the two-way coupled global BATS-R-US–CRCM model. We find different behavior for two pairs of dropouts. For one pair, the same pattern was repeated: (1) weak nightside Region 1 and 2 Birkeland currents before and during the dropout; (2) intensificationmore » of Region 2 currents after the dropout; and (3) a particle injection detected by TWINS after the dropout. The model predicted similar behavior of Birkeland currents. TWINS low-altitude emissions demonstrated high variability during these intervals, indicating high geomagnetic activity in the near-Earth tail region. For the second pair of dropouts, the structure of both Birkeland currents and ENA emissions was relatively stable. The model also showed quasi-stationary behavior of Birkeland currents and simulated ENA emissions with gradual ring current buildup. We confirm that the first pair of dropouts was caused by large-scale motions of the OCB (open–closed boundary) during substorm activity. We show the new result that this OCB motion was associated with global changes in Birkeland (M–I coupling) currents and strong modulation of low-altitude ion precipitation. The second pair of dropouts is the result of smaller OCB disturbances not related to magnetospheric substorms. The local observations of the first pair of dropouts result from a global magnetospheric reconfiguration, which is manifested by ion injections and enhanced ion precipitation detected by TWINS and changes in the structure of Birkeland currents detected by AMPERE. This study demonstrates that multipoint measurements along with the global model results enable the reconstruction of a more complete system-level picture of the dropout events and provides insight into M–I coupling aspects that have not previously been investigated.« less

  5. Wavelet decomposition and radial basis function networks for system monitoring

    NASA Astrophysics Data System (ADS)

    Ikonomopoulos, A.; Endou, A.

    1998-10-01

    Two approaches are coupled to develop a novel collection of black box models for monitoring operational parameters in a complex system. The idea springs from the intention of obtaining multiple predictions for each system variable and fusing them before they are used to validate the actual measurement. The proposed architecture pairs the analytical abilities of the discrete wavelet decomposition with the computational power of radial basis function networks. Members of a wavelet family are constructed in a systematic way and chosen through a statistical selection criterion that optimizes the structure of the network. Network parameters are further optimized through a quasi-Newton algorithm. The methodology is demonstrated utilizing data obtained during two transients of the Monju fast breeder reactor. The models developed are benchmarked with respect to similar regressors based on Gaussian basis functions.

  6. Gap-junction coupling and ATP-sensitive potassium channels in human β -cell clusters: Effects on emergent dynamics

    NASA Astrophysics Data System (ADS)

    Loppini, A.; Pedersen, M. G.; Braun, M.; Filippi, S.

    2017-09-01

    The importance of gap-junction coupling between β cells in pancreatic islets is well established in mouse. Such ultrastructural connections synchronize cellular activity, confine biological heterogeneity, and enhance insulin pulsatility. Dysfunction of coupling has been associated with diabetes and altered β -cell function. However, the role of gap junctions between human β cells is still largely unexplored. By using patch-clamp recordings of β cells from human donors, we previously estimated electrical properties of these channels by mathematical modeling of pairs of human β cells. In this work we revise our estimate by modeling triplet configurations and larger heterogeneous clusters. We find that a coupling conductance in the range 0.005 -0.020 nS/pF can reproduce experiments in almost all the simulated arrangements. We finally explore the consequence of gap-junction coupling of this magnitude between β cells with mutant variants of the ATP-sensitive potassium channels involved in some metabolic disorders and diabetic conditions, translating studies performed on rodents to the human case. Our results are finally discussed from the perspective of therapeutic strategies. In summary, modeling of more realistic clusters with more than two β cells slightly lowers our previous estimate of gap-junction conductance and gives rise to patterns that more closely resemble experimental traces.

  7. Theory and modeling of atmospheric turbulence, part 1

    NASA Technical Reports Server (NTRS)

    1984-01-01

    The cascade transfer which is the only function to describe the mode coupling as the result of the nonlinear hydrodynamic state of turbulence is discussed. A kinetic theory combined with a scaling procedure was developed. The transfer function governs the non-linear mode coupling in strong turbulence. The master equation is consistent with the hydrodynamical system that describes the microdynamic state of turbulence and has the advantages to be homogeneous and have fewer nonlinear terms. The modes are scaled into groups to decipher the governing transport processes and statistical characteristics. An equation of vorticity transport describes the microdynamic state of two dimensional, isotropic and homogeneous, geostrophic turbulence. The equation of evolution of the macrovorticity is derived from group scaling in the form of the Fokker-Planck equation with memory. The microdynamic state of turbulence is transformed into the Liouville equation to derive the kinetic equation of the singlet distribution in turbulence. The collision integral contains a memory, which is analyzed with pair collision and the multiple collision. Two other kinetic equations are developed in parallel for the propagator and the transition probability for the interaction among the groups.

  8. Topological Nodal Cooper Pairing in Doped Weyl Metals

    NASA Astrophysics Data System (ADS)

    Li, Yi; Haldane, F. D. M.

    2018-02-01

    We generalize the concept of Berry connection of the single-electron band structure to that of a two-particle Cooper pairing state between two Fermi surfaces with opposite Chern numbers. Because of underlying Fermi surface topology, the pairing Berry phase acquires nontrivial monopole structure. Consequently, pairing gap functions have topologically protected nodal structure as vortices in the momentum space with the total vorticity solely determined by the pair monopole charge qp. The nodes of gap function behave as the Weyl-Majorana points of the Bogoliubov-de Gennes pairing Hamiltonian. Their relation with the connection patterns of the surface modes from the Weyl band structure and the Majorana surface modes inside the pairing gap is also discussed. Under the approximation of spherical Fermi surfaces, the pairing symmetry are represented by monopole harmonic functions. The lowest possible pairing channel carries angular momentum number j =|qp|, and the corresponding gap functions are holomorphic or antiholomorphic functions on Fermi surfaces. After projected on the Fermi surfaces with nontrivial topology, all the partial-wave channels of pairing interactions acquire the monopole charge qp independent of concrete pairing mechanism.

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

    Schulze, Markus; Soreq, Yotam

    Here, we consider hadronic top quark pair production and pair production in association with a photon or a Z boson to probe electroweak dipole couplings in tb¯W, tt¯γ, and tt¯Z interactions. We demonstrate how measurements of these processes at the 13 TeV LHC can be combined to disentangle and constrain anomalous dipole operators. The construction of cross section ratios allows us to significantly reduce various uncertainties and exploit orthogonal sensitivity between the tt¯γ and tt¯Z couplings. In addition, we show that angular correlations in tt¯ production can be used to constrain the remaining tb¯W dipole operator. Our approach yields excellentmore » sensitivity to the anomalous couplings and can be a further step toward precise and direct measurements of the top quark electroweak interactions.« less

  10. Pulsed source of spectrally uncorrelated and indistinguishable photons at telecom wavelengths.

    PubMed

    Bruno, N; Martin, A; Guerreiro, T; Sanguinetti, B; Thew, R T

    2014-07-14

    We report on the generation of indistinguishable photon pairs at telecom wavelengths based on a type-II parametric down conversion process in a periodically poled potassium titanyl phosphate (PPKTP) crystal. The phase matching, pump laser characteristics and coupling geometry are optimised to obtain spectrally uncorrelated photons with high coupling efficiencies. Four photons are generated by a counter-propagating pump in the same crystal and anlysed via two photon interference experiments between photons from each pair source as well as joint spectral and g((2)) measurements. We obtain a spectral purity of 0.91 and coupling efficiencies around 90% for all four photons without any filtering. These pure indistinguishable photon sources at telecom wavelengths are perfectly adapted for quantum network demonstrations and other multi-photon protocols.

  11. Ultracold Atoms in a Square Lattice with Spin-Orbit Coupling: Charge Order, Superfluidity, and Topological Signatures

    NASA Astrophysics Data System (ADS)

    Rosenberg, Peter; Shi, Hao; Zhang, Shiwei

    2017-12-01

    We present an ab initio, numerically exact study of attractive fermions in square lattices with Rashba spin-orbit coupling. The ground state of this system is a supersolid, with coexisting charge and superfluid order. The superfluid is composed of both singlet and triplet pairs induced by spin-orbit coupling. We perform large-scale calculations using the auxiliary-field quantum Monte Carlo method to provide the first full, quantitative description of the charge, spin, and pairing properties of the system. In addition to characterizing the exotic physics, our results will serve as essential high-accuracy benchmarks for the intense theoretical and especially experimental efforts in ultracold atoms to realize and understand an expanding variety of quantum Hall and topological superconductor systems.

  12. Superfluid response in heavy fermion superconductors

    NASA Astrophysics Data System (ADS)

    Zhong, Yin; Zhang, Lan; Shao, Can; Luo, Hong-Gang

    2017-10-01

    Motivated by a recent London penetration depth measurement [H. Kim, et al., Phys. Rev. Lett. 114, 027003 (2015)] and novel composite pairing scenario [O. Erten, R. Flint, and P. Coleman, Phys. Rev. Lett. 114, 027002 (2015)] of the Yb-doped heavy fermion superconductor CeCoIn5, we revisit the issue of superfluid response in the microscopic heavy fermion lattice model. However, from the literature, an explicit expression for the superfluid response function in heavy fermion superconductors is rare. In this paper, we investigate the superfluid density response function in the celebrated Kondo-Heisenberg model. To be specific, we derive the corresponding formalism from an effective fermionic large- N mean-field pairing Hamiltonian whose pairing interaction is assumed to originate from the effective local antiferromagnetic exchange interaction. Interestingly, we find that the physically correct, temperature-dependent superfluid density formula can only be obtained if the external electromagnetic field is directly coupled to the heavy fermion quasi-particle rather than the bare conduction electron or local moment. Such a unique feature emphasizes the key role of the Kondo-screening-renormalized heavy quasi-particle for low-temperature/energy thermodynamics and transport behaviors. As an important application, the theoretical result is compared to an experimental measurement in heavy fermion superconductors CeCoIn5 and Yb-doped Ce1- x Yb x CoIn5 with fairly good agreement and the transition of the pairing symmetry in the latter material is explained as a simple doping effect. In addition, the requisite formalism for the commonly encountered nonmagnetic impurity and non-local electrodynamic effect are developed. Inspired by the success in explaining classic 115-series heavy fermion superconductors, we expect the present theory will be applied to understand other heavy fermion superconductors such as CeCu2Si2 and more generic multi-band superconductors.

  13. Inorganic proton conducting electrolyte coupled oxide-based dendritic transistors for synaptic electronics.

    PubMed

    Wan, Chang Jin; Zhu, Li Qiang; Zhou, Ju Mei; Shi, Yi; Wan, Qing

    2014-05-07

    Ionic/electronic hybrid devices with synaptic functions are considered to be the essential building blocks for neuromorphic systems and brain-inspired computing. Here, artificial synapses based on indium-zinc-oxide (IZO) transistors gated by nanogranular SiO2 proton-conducting electrolyte films are fabricated on glass substrates. Spike-timing dependent plasticity and paired-pulse facilitation are successfully mimicked in an individual bottom-gate transistor. Most importantly, dynamic logic and dendritic integration established by spatiotemporally correlated spikes are also mimicked in dendritic transistors with two in-plane gates as the presynaptic input terminals.

  14. Pushing x-ray photon correlation spectroscopy beyond the continuous frame rate limit

    DOE PAGES

    Dufresne, Eric M.; Narayanan, Suresh; Sandy, Alec R.; ...

    2016-01-06

    We demonstrate delayed-frame X-ray Photon Correlation Spectroscopy with 120 microsecond time resolution, limited only by sample scattering rates, with a prototype Pixel-array detector capable of taking two image frames separated by 153 ns or less. Although the overall frame rate is currently limited to about 4 frame pairs per second, we easily measured millisecond correlation functions. In conclusion, this technology, coupled to the use of brighter synchrotrons such as Petra III or the NSLS-II should enable X-ray Photon Correlation Spectroscopy on microsecond time scales on a wider variety of materials.

  15. Soliton-dark pulse pair formation in birefringent cavity fiber lasers through cross phase coupling.

    PubMed

    Shao, Guodong; Song, Yufeng; Zhao, Luming; Shen, Deyuan; Tang, Dingyuan

    2015-10-05

    We report on the experimental observation of soliton-dark pulse pair formation in a birefringent cavity fiber laser. Temporal cavity solitons are formed in one polarization mode of the cavity. It is observed that associated with each of the cavity solitons a dark pulse is induced on the CW background of the orthogonal polarization mode. We show that the dark pulse formation is a result of the incoherent cross polarization coupling between the soliton and the CW beam and has a mechanism similar to that of the polarization domain formation observed in the fiber lasers.

  16. Quantum phase transition in dimerised spin-1/2 chains

    NASA Astrophysics Data System (ADS)

    Das, Aparajita; Bhadra, Sreeparna; Saha, Sonali

    2015-11-01

    Quantum phase transition in dimerised antiferromagnetic Heisenberg spin chain has been studied. A staircase structure in the variation of concurrence within strongly coupled pairs with that of external magnetic field has been observed indicating multiple critical (or critical like) points. Emergence of entanglement due to external magnetic field or magnetic entanglement is observed for weakly coupled spin pairs too in the same dimer chain. Though closed dimerised isotropic XXX Heisenberg chains with different dimer strengths were mainly explored, analogous studies on open chains as well as closed anisotropic (XX interaction) chains with tilted external magnetic field have also been studied.

  17. Sensory Regulation of Network Components Underlying Ciliary Locomotion in Hermissenda

    PubMed Central

    Crow, Terry; Tian, Lian-Ming

    2008-01-01

    Ciliary locomotion in the nudibranch mollusk Hermissenda is modulated by the visual and graviceptive systems. Components of the neural network mediating ciliary locomotion have been identified including aggregates of polysensory interneurons that receive monosynaptic input from identified photoreceptors and efferent neurons that activate cilia. Illumination produces an inhibition of type Ii (off-cell) spike activity, excitation of type Ie (on-cell) spike activity, decreased spike activity in type IIIi inhibitory interneurons, and increased spike activity of ciliary efferent neurons. Here we show that pairs of type Ii interneurons and pairs of type Ie interneurons are electrically coupled. Neither electrical coupling or synaptic connections were observed between Ie and Ii interneurons. Coupling is effective in synchronizing dark-adapted spontaneous firing between pairs of Ie and pairs of Ii interneurons. Out-of-phase burst activity, occasionally observed in dark-adapted and light-adapted pairs of Ie and Ii interneurons, suggests that they receive synaptic input from a common presynaptic source or sources. Rhythmic activity is typically not a characteristic of dark-adapted, light-adapted, or light-evoked firing of type I interneurons. However, burst activity in Ie and Ii interneurons may be elicited by electrical stimulation of pedal nerves or generated at the offset of light. Our results indicate that type I interneurons can support the generation of both rhythmic activity and changes in tonic firing depending on sensory input. This suggests that the neural network supporting ciliary locomotion may be multifunctional. However, consistent with the nonmuscular and nonrhythmic characteristics of visually modulated ciliary locomotion, type I interneurons exhibit changes in tonic activity evoked by illumination. PMID:18768639

  18. Interplay of quasiparticle-vibration coupling and pairing correlations on β-decay half-lives

    NASA Astrophysics Data System (ADS)

    Niu, Y. F.; Niu, Z. M.; Colò, G.; Vigezzi, E.

    2018-05-01

    The nuclear β-decay half-lives of Ni and Sn isotopes, around the closed shell nuclei 78Ni and 132Sn, are investigated by computing the distribution of the Gamow-Teller strength using the Quasiparticle Random Phase Approximation (QRPA) with quasiparticle-vibration coupling (QPVC), based on ground-state properties obtained by Hartree-Fock-Bogoliubov (HFB) calculations. We employ the effective interaction SkM* and a zero-range effective pairing force. The half-lives are strongly reduced by including the QPVC. We study in detail the effects of isovector (IV) and isoscalar (IS) pairing. Increasing the IV strength tends to increase the lifetime for nuclei in the proximity of, but lighter than, the closed-shell ones in QRPA calculations, while the effect is significantly reduced by taking into account the QPVC. On the contrary, the IS pairing mainly plays a role for nuclei after the shell closure. Increasing its strength decreases the half-lives, and the effect at QRPA and QRPA+QPVC level is comparable. The effect of IS pairing is particularly pronounced in the case of the Sn isotopes, where it turns out to be instrumental to obtain good agreement with experimental data.

  19. Quantum coupled mutation finder: predicting functionally or structurally important sites in proteins using quantum Jensen-Shannon divergence and CUDA programming.

    PubMed

    Gültas, Mehmet; Düzgün, Güncel; Herzog, Sebastian; Jäger, Sven Joachim; Meckbach, Cornelia; Wingender, Edgar; Waack, Stephan

    2014-04-03

    The identification of functionally or structurally important non-conserved residue sites in protein MSAs is an important challenge for understanding the structural basis and molecular mechanism of protein functions. Despite the rich literature on compensatory mutations as well as sequence conservation analysis for the detection of those important residues, previous methods often rely on classical information-theoretic measures. However, these measures usually do not take into account dis/similarities of amino acids which are likely to be crucial for those residues. In this study, we present a new method, the Quantum Coupled Mutation Finder (QCMF) that incorporates significant dis/similar amino acid pair signals in the prediction of functionally or structurally important sites. The result of this study is twofold. First, using the essential sites of two human proteins, namely epidermal growth factor receptor (EGFR) and glucokinase (GCK), we tested the QCMF-method. The QCMF includes two metrics based on quantum Jensen-Shannon divergence to measure both sequence conservation and compensatory mutations. We found that the QCMF reaches an improved performance in identifying essential sites from MSAs of both proteins with a significantly higher Matthews correlation coefficient (MCC) value in comparison to previous methods. Second, using a data set of 153 proteins, we made a pairwise comparison between QCMF and three conventional methods. This comparison study strongly suggests that QCMF complements the conventional methods for the identification of correlated mutations in MSAs. QCMF utilizes the notion of entanglement, which is a major resource of quantum information, to model significant dissimilar and similar amino acid pair signals in the detection of functionally or structurally important sites. Our results suggest that on the one hand QCMF significantly outperforms the previous method, which mainly focuses on dissimilar amino acid signals, to detect essential sites in proteins. On the other hand, it is complementary to the existing methods for the identification of correlated mutations. The method of QCMF is computationally intensive. To ensure a feasible computation time of the QCMF's algorithm, we leveraged Compute Unified Device Architecture (CUDA).The QCMF server is freely accessible at http://qcmf.informatik.uni-goettingen.de/.

  20. Functional Characterization and Signaling Systems of Corazonin and Red Pigment Concentrating Hormone in the Green Shore Crab, Carcinus maenas

    PubMed Central

    Alexander, Jodi L.; Oliphant, Andrew; Wilcockson, David C.; Audsley, Neil; Down, Rachel E.; Lafont, Rene; Webster, Simon G.

    2018-01-01

    Neuropeptides play a central role as neurotransmitters, neuromodulators and hormones in orchestrating arthropod physiology. The post-genomic surge in identified neuropeptides and their putative receptors has not been matched by functional characterization of ligand-receptor pairs. Indeed, until very recently no G protein-coupled receptors (GPCRs) had been functionally defined in any crustacean. Here we explore the structurally-related, functionally-diverse gonadotropin-releasing hormone paralogs, corazonin (CRZ) and red-pigment concentrating hormone (RPCH) and their G-protein coupled receptors (GPCRs) in the crab, Carcinus maenas. Using aequorin luminescence to measure in vitro Ca2+ mobilization we demonstrated receptor-ligand pairings of CRZ and RPCH. CRZR-activated cell signaling in a dose-dependent manner (EC50 0.75 nM) and comparative studies with insect CRZ peptides suggest that the C-terminus of this peptide is important in receptor-ligand interaction. RPCH interacted with RPCHR with extremely high sensitivity (EC50 20 pM). Neither receptor bound GnRH, nor the AKH/CRZ-related peptide. Transcript distributions of both receptors indicate that CRZR expression was, unexpectedly, restricted to the Y-organs (YO). Application of CRZ peptide to YO had no effect on ecdysteroid biosynthesis, excepting a modest stimulation in early post-molt. CRZ had no effect on heart activity, blood glucose levels, lipid mobilization or pigment distribution in chromatophores, a scenario that reflected the distribution of its mRNA. Apart from the well-known activity of RPCH as a chromatophorotropin, it also indirectly elicited hyperglycemia (which was eyestalk-dependent). RPCHR mRNA was also expressed in the ovary, indicating possible roles in reproduction. The anatomy of CRZ and RPCH neurons in the nervous system is described in detail by immunohistochemistry and in situ hybridization. Each peptide has extensive but non-overlapping distribution in the CNS, and neuroanatomy suggests that both are possibly released from the post-commissural organs. This study is one of the first to deorphanize a GPCR in a crustacean and to provide evidence for hitherto unknown and diverse functions of these evolutionarily-related neuropeptides. PMID:29379412

  1. Bendable X-ray Optics at the ALS: Design, Tuning, Performance and Applications

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

    Advanced Light Source, Lawrence Berkeley National Laboratory; Yashchuk, Valeriy V.; Church, Matthew N.

    2008-09-08

    We review the development at the Advanced Light Source (ALS) of bendable x-ray optics widely used for focusing of beams of soft and hard x-rays. Typically, the focusing is divided in the tangential and sagittal directions into two elliptically cylindrical reflecting elements, the so-called Kirkpatrick-Baez (KB) pair [1]. Because fabrication of elliptical surfaces is complicated, the cost of directly fabricated tangential elliptical cylinders is often prohibitive. This is in contrast to flat optics, that are simpler to manufacture and easier to measure by conventional interferometry. The figure of a flat substrate can be changed by placing torques (couples) at eachmore » end. Equal couples form a tangential cylinder, and unequal couples can approximate a tangential ellipse or parabola. We review the nature of the bending, requirements and approaches to the mechanical design, and describe a technique developed at the ALS Optical Metrology Laboratory (OML) for optimal tuning of bendable mirrors before installation in the beamline [2]. The tuning technique adapts a method previously used to adjust bendable mirrors on synchrotron radiation beamlines [3]. However, in our case, optimal tuning of a bendable mirror is based on surface slope trace data obtained with a slope measuring instrument--in our case, the long trace profiler (LTP). We show that due to the near linearity of the bending problem, the minimal set of data, necessary for tuning of two benders, consists of only three slope traces measured before and after a single adjustment of each bending couple. We provide an algorithm that was used in dedicated software for finding optimal settings for the mirror benders. The algorithm is based on the method of regression analysis with experimentally found characteristic functions of the benders. The resulting approximation to the functional dependence of the desired slope shape provides nearly final settings for the benders. Moreover, the characteristic functions of the benders found in the course of tuning, can be used for retuning of the optics to a new desired shape without removing it from the beamline and re-measuring with the LTP. The result of practical use of the developed technique to precisely tune a KB mirror used at the ALS for micro-focusing is also presented. We also describe a simple ray trace using the profiler data which shows expected performance in the beamline and compare the simulation with experimental data. In summary, we also discuss the next steps in the systematic improvement of optical performance for the application of KB pairs in synchrotron beamlines at the ALS.« less

  2. Spin-exciton interaction and related micro-photoluminescence spectra of ZnSe:Mn DMS nanoribbon

    NASA Astrophysics Data System (ADS)

    Hou, Lipeng; Zhou, Weichang; Zou, Bingsuo; Zhang, Yu; Han, Junbo; Yang, Xinxin; Gong, Zhihong; Li, Jingbo; Xie, Sishen; Shi, Li-Jie

    2017-03-01

    For their spintronic applications the magnetic and optical properties of diluted magnetic semiconductors (DMS) have been studied widely. However, the exact relationships between the magnetic interactions and optical emission behaviors in DMS are not well understood yet due to their complicated microstructural and compositional characters from different growth and preparation techniques. Manganese (Mn) doped ZnSe nanoribbons with high quality were obtained by using the chemical vapor deposition (CVD) method. Successful Mn ion doping in a single ZnSe nanoribbon was identified by elemental energy-dispersive x-ray spectroscopy mapping and micro-photoluminescence (PL) mapping of intrinsic d-d optical transition at 580 nm, i.e. the transition of 4 T 1(4 G) → 6 A 1(6 s),. Besides the d-d transition PL peak at 580 nm, two other PL peaks related to Mn ion aggregates in the ZnSe lattice were detected at 664 nm and 530 nm, which were assigned to the d-d transitions from the Mn2+-Mn2+ pairs with ferromagnetic (FM) coupling and antiferromagnetic (AFM) coupling, respectively. Moreover, AFM pair formation goes along with strong coupling with acoustic phonon or structural defects. These arguments were supported by temperature-dependent PL spectra, power-dependent PL lifetimes, and first-principle calculations. Due to the ferromagnetic pair existence, an exciton magnetic polaron (EMP) is formed and emits at 460 nm. Defect existence favors the AFM pair, which also can account for its giant enhancement of spin-orbital coupling and the spin Hall effect observed in PRL 97, 126603(2006) and PRL 96, 196404(2006). These emission results of DMS reflect their relation to local sp-d hybridization, spin-spin magnetic coupling, exciton-spin or phonon interactions covering structural relaxations. This kind of material can be used to study the exciton-spin interaction and may find applications in spin-related photonic devices besides spintronics.

  3. Search for Higgs boson pair production in events with two bottom quarks and two tau leptons in proton–proton collisions at s = 13 TeV

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

    Sirunyan, A. M.; Tumasyan, A.; Adam, W.

    A search for the production of Higgs boson pairs in proton–proton collisions at a centre-of-mass energy of 13 TeV is presented, using a data sample corresponding to an integrated luminosity of 35.9 fb -1 collected with the CMS detector at the LHC. Events with one Higgs boson decaying into two bottom quarks and the other decaying into two τ leptons are explored to investigate both resonant and nonresonant production mechanisms. The data are found to be consistent, within uncertainties, with the standard model background predictions. For resonant production, upper limits at the 95% confidence level are set on the productionmore » cross section for Higgs boson pairs as a function of the hypothesized resonance mass and are interpreted in the context of the minimal supersymmetric standard model. For nonresonant production, upper limits on the production cross section constrain the parameter space for anomalous Higgs boson couplings. The observed (expected) upper limit at 95% confidence level corresponds to about 30 (25) times the prediction of the standard model.« less

  4. The limits of the nuclear landscape explored by the relativistic continuum Hartree-Bogoliubov theory

    NASA Astrophysics Data System (ADS)

    Xia, X. W.; Lim, Y.; Zhao, P. W.; Liang, H. Z.; Qu, X. Y.; Chen, Y.; Liu, H.; Zhang, L. F.; Zhang, S. Q.; Kim, Y.; Meng, J.

    2018-05-01

    The ground-state properties of nuclei with 8 ⩽ Z ⩽ 120 from the proton drip line to the neutron drip line have been investigated using the spherical relativistic continuum Hartree-Bogoliubov (RCHB) theory with the relativistic density functional PC-PK1. With the effects of the continuum included, there are totally 9035 nuclei predicted to be bound, which largely extends the existing nuclear landscapes predicted with other methods. The calculated binding energies, separation energies, neutron and proton Fermi surfaces, root-mean-square (rms) radii of neutron, proton, matter, and charge distributions, ground-state spins and parities are tabulated. The extension of the nuclear landscape obtained with RCHB is discussed in detail, in particular for the neutron-rich side, in comparison with the relativistic mean field calculations without pairing correlations and also other predicted landscapes. It is found that the coupling between the bound states and the continuum due to the pairing correlations plays an essential role in extending the nuclear landscape. The systematics of the separation energies, radii, densities, potentials and pairing energies of the RCHB calculations are also discussed. In addition, the α-decay energies and proton emitters based on the RCHB calculations are investigated.

  5. Search for Higgs boson pair production in events with two bottom quarks and two tau leptons in proton–proton collisions at s = 13 TeV

    DOE PAGES

    Sirunyan, A. M.; Tumasyan, A.; Adam, W.; ...

    2018-03-01

    A search for the production of Higgs boson pairs in proton–proton collisions at a centre-of-mass energy of 13 TeV is presented, using a data sample corresponding to an integrated luminosity of 35.9 fb -1 collected with the CMS detector at the LHC. Events with one Higgs boson decaying into two bottom quarks and the other decaying into two τ leptons are explored to investigate both resonant and nonresonant production mechanisms. The data are found to be consistent, within uncertainties, with the standard model background predictions. For resonant production, upper limits at the 95% confidence level are set on the productionmore » cross section for Higgs boson pairs as a function of the hypothesized resonance mass and are interpreted in the context of the minimal supersymmetric standard model. For nonresonant production, upper limits on the production cross section constrain the parameter space for anomalous Higgs boson couplings. The observed (expected) upper limit at 95% confidence level corresponds to about 30 (25) times the prediction of the standard model.« less

  6. Sigma meson in vacuum and nuclear matter

    NASA Astrophysics Data System (ADS)

    Menchaca-Maciel, M. C.; Morones-Ibarra, J. R.

    2013-04-01

    We have obtained the value of the interaction constant g σππ that adjusts the values obtained in the E791 Collaboration at Fermilab and BES Collaboration at the Beijing Electron Positron Collider experiments. To get this we have used the concept of critical width to make compatible the parameters obtained from the Breit-Wigner formula and those obtained from the density function. Also, the total width and effective mass modification of the sigma meson in nuclear matter has been studied in the Walecka model, assuming that the sigma couples to a pair of nucleon-antinucleon states and to particle-hole states, including the in-medium effect of sigma-omega mixing. We have considered, for completeness, the coupling of sigma to two virtual pions. We have found that the sigma meson mass decreases with respect to its value in vacuum and that the contribution of the sigma-omega mixing effect on the mass shift is relevant.

  7. Measurement of the Zγ production cross section in pp collisions at 8 TeV and search for anomalous triple gauge boson couplings

    DOE PAGES

    Khachatryan, Vardan

    2015-04-29

    The cross section for the production of Zγ in proton-proton collisions at 8 TeV is measured based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 19.5 fb -1. Events with an oppositely-charged pair of muons or electrons together with an isolated photon are selected. Furthermore, the differential cross section as a function of the photon transverse momentum is measured inclusively and exclusively, where the exclusive selection applies a veto on central jets. These observed cross sections are compatible with the expectations of next-to-next-to-leading-order quantum chromodynamics. As a result, limits on anomalous triplemore » gauge couplings of ZZγ and Zγγ are set that improve on previous experimental results obtained with the charged lepton decay modes of the Z boson.« less

  8. Dynamical Bayesian inference of time-evolving interactions: From a pair of coupled oscillators to networks of oscillators

    NASA Astrophysics Data System (ADS)

    Duggento, Andrea; Stankovski, Tomislav; McClintock, Peter V. E.; Stefanovska, Aneta

    2012-12-01

    Living systems have time-evolving interactions that, until recently, could not be identified accurately from recorded time series in the presence of noise. Stankovski [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.109.024101 109, 024101 (2012)] introduced a method based on dynamical Bayesian inference that facilitates the simultaneous detection of time-varying synchronization, directionality of influence, and coupling functions. It can distinguish unsynchronized dynamics from noise-induced phase slips. The method is based on phase dynamics, with Bayesian inference of the time-evolving parameters being achieved by shaping the prior densities to incorporate knowledge of previous samples. We now present the method in detail using numerically generated data, data from an analog electronic circuit, and cardiorespiratory data. We also generalize the method to encompass networks of interacting oscillators and thus demonstrate its applicability to small-scale networks.

  9. Theoretical study of the alkaline-earth metal superoxides BeO2 through SrO2

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Partridge, Harry; Sodupe, Mariona; Langhoff, Stephen R.

    1992-01-01

    Three competing bonding mechanisms have been identified for the alkaline-earth metal superoxides: these result in a change in the optimal structure and ground state as the alkaline-earth metal becomes heavier. For example, BeO2 has a linear 3Sigma(-)g ground-state structure, whereas both CaO2 and SrO2 have C(2v)1A1 structures. For MgO2, the theoretical calculations are less definitive, as the 3A2 C(2v) structure is computed to lie only about 3 kcal/mol above the 3Sigma(-)g linear structure. The bond dissociation energies for the alkaline-earth metal superoxides have been computed using extensive Gaussian basis sets and treating electron correlation at the modified coupled-pair functional or coupled-cluster singles and doubles level with a perturbational estimate of the triple excitations.

  10. Chiral Majorana fermion modes regulated by a scanning tunneling microscope tip

    NASA Astrophysics Data System (ADS)

    Zhou, Yan-Feng; Hou, Zhe; Zhang, Ying-Tao; Sun, Qing-Feng

    2018-03-01

    The Majorana fermion can be described by a real wave function with only two phases (zero and π ) which provide a controllable degree of freedom. We propose a strategy to regulate the phase of the chiral Majorana state by coupling with a scanning tunneling microscope tip in a system consisting of a quantum anomalous Hall insulator coupled with a superconductor. With the change in the chemical potential, the chiral Majorana state can be tuned alternately between zero and π , in which the perfect normal tunneling and perfect crossed Andreev reflection appear, respectively. The perfect crossed Andreev reflection, by which a Cooper pair can be split into two electrons going into different terminals completely, leads to a pumping current and distinct quantized resistances. These findings may provide a signature of Majorana fermions and pave a feasible avenue to regulate the phase of the Majorana state.

  11. Measurement of the Z γ production cross section in pp collisions at 8 TeV and search for anomalous triple gauge boson couplings

    NASA Astrophysics Data System (ADS)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; Ochesanu, S.; Rougny, R.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Daci, N.; Heracleous, N.; Keaveney, J.; Lowette, S.; Maes, M.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Dobur, D.; Favart, L.; Gay, A. P. R.; Grebenyuk, A.; Léonard, A.; Mohammadi, A.; Perniè, L.; Randle-conde, A.; Reis, T.; Seva, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Zenoni, F.; Adler, V.; Beernaert, K.; Benucci, L.; Cimmino, A.; Costantini, S.; Crucy, S.; Dildick, S.; Fagot, A.; Garcia, G.; Mccartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva Diblen, S.; Sigamani, M.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; Da Silveira, G. G.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Nuttens, C.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Dos Reis Martins, T.; Molina, J.; Mora Herrera, C.; Pol, M. E.; Rebello Teles, P.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santaolalla, J.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Bernardes, C. A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Aleksandrov, A.; Genchev, V.; Hadjiiska, R.; Iaydjiev, P.; Marinov, A.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. H.; Plestina, R.; Romeo, F.; Tao, J.; Wang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Li, Q.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Xu, Z.; Zou, W.; Avila, C.; Cabrera, A.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Mekterovic, D.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Bodlak, M.; Finger, M.; Finger, M.; Assran, Y.; Ellithi Kamel, A.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Eerola, P.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. 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A.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Xiao, H.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.; Bontenackels, M.; Edelhoff, M.; Feld, L.; Heister, A.; Klein, K.; Lipinski, M.; Ostapchuk, A.; Preuten, M.; Raupach, F.; Sammet, J.; Schael, S.; Schulte, J. F.; Weber, H.; Wittmer, B.; Zhukov, V.; Ata, M.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Erdmann, M.; Fischer, R.; Güth, A.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Klingebiel, D.; Knutzen, S.; Kreuzer, P.; Merschmeyer, M.; Meyer, A.; Millet, P.; Olschewski, M.; Padeken, K.; Papacz, P.; Reithler, H.; Schmitz, S. A.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Weber, M.; Cherepanov, V.; Erdogan, Y.; Flügge, G.; Geenen, H.; Geisler, M.; Haj Ahmad, W.; Hoehle, F.; Kargoll, B.; Kress, T.; Kuessel, Y.; Künsken, A.; Lingemann, J.; Nowack, A.; Nugent, I. M.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Asin, I.; Bartosik, N.; Behr, J.; Behrens, U.; Bell, A. J.; Bethani, A.; Borras, K.; Burgmeier, A.; Cakir, A.; Calligaris, L.; Campbell, A.; Choudhury, S.; Costanza, F.; Diez Pardos, C.; Dolinska, G.; Dooling, S.; Dorland, T.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Flucke, G.; Garay Garcia, J.; Geiser, A.; Gunnellini, P.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Kasemann, M.; Katsas, P.; Kieseler, J.; Kleinwort, C.; Korol, I.; Krücker, D.; Lange, W.; Leonard, J.; Lipka, K.; Lobanov, A.; Lohmann, W.; Lutz, B.; Mankel, R.; Marfin, I.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Naumann-Emme, S.; Nayak, A.; Ntomari, E.; Perrey, H.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Ribeiro Cipriano, P. M.; Roland, B.; Ron, E.; Sahin, M. Ö.; Salfeld-Nebgen, J.; Saxena, P.; Schoerner-Sadenius, T.; Schröder, M.; Seitz, C.; Spannagel, S.; Vargas Trevino, A. D. R.; Walsh, R.; Wissing, C.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Erfle, J.; Garutti, E.; Goebel, K.; Görner, M.; Haller, J.; Hoffmann, M.; Höing, R. S.; Junkes, A.; Kirschenmann, H.; Klanner, R.; Kogler, R.; Lange, J.; Lapsien, T.; Lenz, T.; Marchesini, I.; Ott, J.; Peiffer, T.; Perieanu, A.; Pietsch, N.; Poehlsen, J.; Poehlsen, T.; Rathjens, D.; Sander, C.; Schettler, H.; Schleper, P.; Schlieckau, E.; Schmidt, A.; Seidel, M.; Sola, V.; Stadie, H.; Steinbrück, G.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Barth, C.; Baus, C.; Berger, J.; Böser, C.; Butz, E.; Chwalek, T.; De Boer, W.; Descroix, A.; Dierlamm, A.; Feindt, M.; Frensch, F.; Giffels, M.; Gilbert, A.; Hartmann, F.; Hauth, T.; Husemann, U.; Katkov, I.; Kornmayer, A.; Lobelle Pardo, P.; Mozer, M. U.; Müller, T.; Müller, Th.; Nürnberg, A.; Quast, G.; Rabbertz, K.; Röcker, S.; Simonis, H. J.; Stober, F. M.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weiler, T.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Markou, A.; Markou, C.; Psallidas, A.; Topsis-Giotis, I.; Agapitos, A.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Stiliaris, E.; Aslanoglou, X.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Strologas, J.; Bencze, G.; Hajdu, C.; Hidas, P.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Molnar, J.; Palinkas, J.; Szillasi, Z.; Makovec, A.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Swain, S. K.; Beri, S. B.; Bhatnagar, V.; Gupta, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, M.; Kumar, R.; Mittal, M.; Nishu, N.; Singh, J. B.; Kumar, Ashok; Kumar, Arun; Ahuja, S.; Bhardwaj, A.; Choudhary, B. C.; Kumar, A.; Malhotra, S.; Naimuddin, M.; Ranjan, K.; Sharma, V.; Banerjee, S.; Bhattacharya, S.; Chatterjee, K.; Dutta, S.; Gomber, B.; Jain, Sa.; Jain, Sh.; Khurana, R.; Modak, A.; Mukherjee, S.; Roy, D.; Sarkar, S.; Sharan, M.; Abdulsalam, A.; Dutta, D.; Kumar, V.; Mohanty, A. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Banerjee, S.; Bhowmik, S.; Chatterjee, R. M.; Dewanjee, R. K.; Dugad, S.; Ganguly, S.; Ghosh, S.; Guchait, M.; Gurtu, A.; Kole, G.; Kumar, S.; Maity, M.; Majumder, G.; Mazumdar, K.; Mohanty, G. B.; Parida, B.; Sudhakar, K.; Wickramage, N.; Bakhshiansohi, H.; Behnamian, H.; Etesami, S. M.; Fahim, A.; Goldouzian, R.; Khakzad, M.; Mohammadi Najafabadi, M.; Naseri, M.; Paktinat Mehdiabadi, S.; Rezaei Hosseinabadi, F.; Safarzadeh, B.; Zeinali, M.; Felcini, M.; Grunewald, M.; Abbrescia, M.; Calabria, C.; Chhibra, S. S.; Colaleo, A.; Creanza, D.; De Filippis, N.; De Palma, M.; Fiore, L.; Iaselli, G.; Maggi, G.; Maggi, M.; My, S.; Nuzzo, S.; Pompili, A.; Pugliese, G.; Radogna, R.; Selvaggi, G.; Sharma, A.; Silvestris, L.; Venditti, R.; Verwilligen, P.; Abbiendi, G.; Benvenuti, A. C.; Bonacorsi, D.; Braibant-Giacomelli, S.; Brigliadori, L.; Campanini, R.; Capiluppi, P.; Castro, A.; Cavallo, F. R.; Codispoti, G.; Cuffiani, M.; Dallavalle, G. M.; Fabbri, F.; Fanfani, A.; Fasanella, D.; Giacomelli, P.; Grandi, C.; Guiducci, L.; Marcellini, S.; Masetti, G.; Montanari, A.; Navarria, F. L.; Perrotta, A.; Primavera, F.; Rossi, A. M.; Rovelli, T.; Siroli, G. P.; Tosi, N.; Travaglini, R.; Albergo, S.; Cappello, G.; Chiorboli, M.; Costa, S.; Giordano, F.; Potenza, R.; Tricomi, A.; Tuve, C.; Barbagli, G.; Ciulli, V.; Civinini, C.; D'Alessandro, R.; Focardi, E.; Gallo, E.; Gonzi, S.; Gori, V.; Lenzi, P.; Meschini, M.; Paoletti, S.; Sguazzoni, G.; Tropiano, A.; Benussi, L.; Bianco, S.; Fabbri, F.; Piccolo, D.; Ferretti, R.; Ferro, F.; Lo Vetere, M.; Robutti, E.; Tosi, S.; Dinardo, M. E.; Fiorendi, S.; Gennai, S.; Gerosa, R.; Ghezzi, A.; Govoni, P.; Lucchini, M. T.; Malvezzi, S.; Manzoni, R. A.; Martelli, A.; Marzocchi, B.; Menasce, D.; Moroni, L.; Paganoni, M.; Pedrini, D.; Ragazzi, S.; Redaelli, N.; Tabarelli de Fatis, T.; Buontempo, S.; Cavallo, N.; Di Guida, S.; Fabozzi, F.; Iorio, A. O. M.; Lista, L.; Meola, S.; Merola, M.; Paolucci, P.; Azzi, P.; Bacchetta, N.; Bisello, D.; Carlin, R.; Checchia, P.; Dall'Osso, M.; Dorigo, T.; Dosselli, U.; Galanti, M.; Gasparini, U.; Gozzelino, A.; Lacaprara, S.; Margoni, M.; Meneguzzo, A. T.; Montecassiano, F.; Passaseo, M.; Pazzini, J.; Pegoraro, M.; Pozzobon, N.; Ronchese, P.; Simonetto, F.; Torassa, E.; Tosi, M.; Ventura, S.; Zotto, P.; Zucchetta, A.; Gabusi, M.; Ratti, S. P.; Re, V.; Riccardi, C.; Salvini, P.; Vitulo, P.; Biasini, M.; Bilei, G. M.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Mantovani, G.; Menichelli, M.; Saha, A.; Santocchia, A.; Spiezia, A.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bernardini, J.; Boccali, T.; Broccolo, G.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Donato, S.; Fedi, G.; Fiori, F.; Foà, L.; Giassi, A.; Grippo, M. T.; Ligabue, F.; Lomtadze, T.; Martini, L.; Messineo, A.; Moon, C. S.; Palla, F.; Rizzi, A.; Savoy-Navarro, A.; Serban, A. T.; Spagnolo, P.; Squillacioti, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. 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A.; Khurshid, T.; Shoaib, M.; Bialkowska, H.; Bluj, M.; Boimska, B.; Frueboes, T.; Górski, M.; Kazana, M.; Nawrocki, K.; Romanowska-Rybinska, K.; Szleper, M.; Zalewski, P.; Brona, G.; Bunkowski, K.; Cwiok, M.; Dominik, W.; Doroba, K.; Kalinowski, A.; Konecki, M.; Krolikowski, J.; Misiura, M.; Olszewski, M.; Bargassa, P.; Beirão Da Cruz E Silva, C.; Faccioli, P.; Ferreira Parracho, P. G.; Gallinaro, M.; Lloret Iglesias, L.; Nguyen, F.; Rodrigues Antunes, J.; Seixas, J.; Varela, J.; Vischia, P.; Afanasiev, S.; Gavrilenko, M.; Golutvin, I.; Karjavin, V.; Konoplyanikov, V.; Korenkov, V.; Lanev, A.; Malakhov, A.; Matveev, V.; Mitsyn, V. V.; Moisenz, P.; Palichik, V.; Perelygin, V.; Shmatov, S.; Skatchkov, N.; Smirnov, V.; Tikhonenko, E.; Zarubin, A.; Golovtsov, V.; Ivanov, Y.; Kim, V.; Kuznetsova, E.; Levchenko, P.; Murzin, V.; Oreshkin, V.; Smirnov, I.; Sulimov, V.; Uvarov, L.; Vavilov, S.; Vorobyev, A.; Vorobyev, An.; Andreev, Yu.; Dermenev, A.; Gninenko, S.; Golubev, N.; Kirsanov, M.; Krasnikov, N.; Pashenkov, A.; Tlisov, D.; Toropin, A.; Epshteyn, V.; Gavrilov, V.; Lychkovskaya, N.; Popov, V.; Pozdnyakov, I.; Safronov, G.; Semenov, S.; Spiridonov, A.; Stolin, V.; Vlasov, E.; Zhokin, A.; Andreev, V.; Azarkin, M.; Dremin, I.; Kirakosyan, M.; Leonidov, A.; Mesyats, G.; Rusakov, S. V.; Vinogradov, A.; Belyaev, A.; Boos, E.; Dubinin, M.; Dudko, L.; Ershov, A.; Gribushin, A.; Klyukhin, V.; Kodolova, O.; Lokhtin, I.; Obraztsov, S.; Petrushanko, S.; Savrin, V.; Snigirev, A.; Azhgirey, I.; Bayshev, I.; Bitioukov, S.; Kachanov, V.; Kalinin, A.; Konstantinov, D.; Krychkine, V.; Petrov, V.; Ryutin, R.; Sobol, A.; Tourtchanovitch, L.; Troshin, S.; Tyurin, N.; Uzunian, A.; Volkov, A.; Adzic, P.; Ekmedzic, M.; Milosevic, J.; Rekovic, V.; Alcaraz Maestre, J.; Battilana, C.; Calvo, E.; Cerrada, M.; Chamizo Llatas, M.; Colino, N.; De La Cruz, B.; Delgado Peris, A.; Domínguez Vázquez, D.; Escalante Del Valle, A.; Fernandez Bedoya, C.; Fernández Ramos, J. P.; Flix, J.; Fouz, M. C.; Garcia-Abia, P.; Gonzalez Lopez, O.; Goy Lopez, S.; Hernandez, J. M.; Josa, M. I.; Navarro De Martino, E.; Pérez-Calero Yzquierdo, A.; Puerta Pelayo, J.; Quintario Olmeda, A.; Redondo, I.; Romero, L.; Soares, M. S.; Albajar, C.; de Trocóniz, J. F.; Missiroli, M.; Moran, D.; Brun, H.; Cuevas, J.; Fernandez Menendez, J.; Folgueras, S.; Gonzalez Caballero, I.; Brochero Cifuentes, J. A.; Cabrillo, I. J.; Calderon, A.; Duarte Campderros, J.; Fernandez, M.; Gomez, G.; Graziano, A.; Lopez Virto, A.; Marco, J.; Marco, R.; Martinez Rivero, C.; Matorras, F.; Munoz Sanchez, F. J.; Piedra Gomez, J.; Rodrigo, T.; Rodríguez-Marrero, A. Y.; Ruiz-Jimeno, A.; Scodellaro, L.; Vila, I.; Vilar Cortabitarte, R.; Abbaneo, D.; Auffray, E.; Auzinger, G.; Bachtis, M.; Baillon, P.; Ball, A. H.; Barney, D.; Benaglia, A.; Bendavid, J.; Benhabib, L.; Benitez, J. F.; Bloch, P.; Bocci, A.; Bonato, A.; Bondu, O.; Botta, C.; Breuker, H.; Camporesi, T.; Cerminara, G.; Colafranceschi, S.; D'Alfonso, M.; d'Enterria, D.; Dabrowski, A.; David, A.; De Guio, F.; De Roeck, A.; De Visscher, S.; Di Marco, E.; Dobson, M.; Dordevic, M.; Dorney, B.; Dupont-Sagorin, N.; Elliott-Peisert, A.; Franzoni, G.; Funk, W.; Gigi, D.; Gill, K.; Giordano, D.; Girone, M.; Glege, F.; Guida, R.; Gundacker, S.; Guthoff, M.; Hammer, J.; Hansen, M.; Harris, P.; Hegeman, J.; Innocente, V.; Janot, P.; Kousouris, K.; Krajczar, K.; Lecoq, P.; Lourenço, C.; Magini, N.; Malgeri, L.; Mannelli, M.; Marrouche, J.; Masetti, L.; Meijers, F.; Mersi, S.; Meschi, E.; Moortgat, F.; Morovic, S.; Mulders, M.; Orsini, L.; Pape, L.; Perez, E.; Petrilli, A.; Petrucciani, G.; Pfeiffer, A.; Pimiä, M.; Piparo, D.; Plagge, M.; Racz, A.; Rolandi, G.; Rovere, M.; Sakulin, H.; Schäfer, C.; Schwick, C.; Sharma, A.; Siegrist, P.; Silva, P.; Simon, M.; Sphicas, P.; Spiga, D.; Steggemann, J.; Stieger, B.; Stoye, M.; Takahashi, Y.; Treille, D.; Tsirou, A.; Veres, G. I.; Wardle, N.; Wöhri, H. K.; Wollny, H.; Zeuner, W. D.; Bertl, W.; Deiters, K.; Erdmann, W.; Horisberger, R.; Ingram, Q.; Kaestli, H. C.; Kotlinski, D.; Langenegger, U.; Renker, D.; Rohe, T.; Bachmair, F.; Bäni, L.; Bianchini, L.; Buchmann, M. A.; Casal, B.; Chanon, N.; Dissertori, G.; Dittmar, M.; Donegà, M.; Dünser, M.; Eller, P.; Grab, C.; Hits, D.; Hoss, J.; Lustermann, W.; Mangano, B.; Marini, A. C.; Marionneau, M.; Martinez Ruiz del Arbol, P.; Masciovecchio, M.; Meister, D.; Mohr, N.; Musella, P.; Nägeli, C.; Nessi-Tedaldi, F.; Pandolfi, F.; Pauss, F.; Perrozzi, L.; Peruzzi, M.; Quittnat, M.; Rebane, L.; Rossini, M.; Starodumov, A.; Takahashi, M.; Theofilatos, K.; Wallny, R.; Weber, H. A.; Amsler, C.; Canelli, M. F.; Chiochia, V.; De Cosa, A.; Hinzmann, A.; Hreus, T.; Kilminster, B.; Lange, C.; Millan Mejias, B.; Ngadiuba, J.; Pinna, D.; Robmann, P.; Ronga, F. J.; Taroni, S.; Verzetti, M.; Yang, Y.; Cardaci, M.; Chen, K. H.; Ferro, C.; Kuo, C. M.; Lin, W.; Lu, Y. J.; Volpe, R.; Yu, S. S.; Chang, P.; Chang, Y. H.; Chao, Y.; Chen, K. F.; Chen, P. H.; Dietz, C.; Grundler, U.; Hou, W.-S.; Liu, Y. F.; Lu, R.-S.; Petrakou, E.; Tzeng, Y. M.; Wilken, R.; Asavapibhop, B.; Singh, G.; Srimanobhas, N.; Suwonjandee, N.; Adiguzel, A.; Bakirci, M. N.; Cerci, S.; Dozen, C.; Dumanoglu, I.; Eskut, E.; Girgis, S.; Gokbulut, G.; Guler, Y.; Gurpinar, E.; Hos, I.; Kangal, E. E.; Topaksu, A. Kayis; Onengut, G.; Ozdemir, K.; Ozturk, S.; Polatoz, A.; Sunar Cerci, D.; Tali, B.; Topakli, H.; Vergili, M.; Zorbilmez, C.; Akin, I. V.; Bilin, B.; Bilmis, S.; Gamsizkan, H.; Isildak, B.; Karapinar, G.; Ocalan, K.; Sekmen, S.; Surat, U. E.; Yalvac, M.; Zeyrek, M.; Albayrak, E. A.; Gülmez, E.; Kaya, M.; Kaya, O.; Yetkin, T.; Cankocak, K.; Vardarlı, F. I.; Levchuk, L.; Sorokin, P.; Brooke, J. J.; Clement, E.; Cussans, D.; Flacher, H.; Goldstein, J.; Grimes, M.; Heath, G. P.; Heath, H. F.; Jacob, J.; Kreczko, L.; Lucas, C.; Meng, Z.; Newbold, D. M.; Paramesvaran, S.; Poll, A.; Sakuma, T.; Seif El Nasr-storey, S.; Senkin, S.; Smith, V. J.; Bell, K. W.; Belyaev, A.; Brew, C.; Brown, R. M.; Cockerill, D. J. A.; Coughlan, J. A.; Harder, K.; Harper, S.; Olaiya, E.; Petyt, D.; Shepherd-Themistocleous, C. H.; Thea, A.; Tomalin, I. R.; Williams, T.; Womersley, W. J.; Worm, S. D.; Baber, M.; Bainbridge, R.; Buchmuller, O.; Burton, D.; Colling, D.; Cripps, N.; Dauncey, P.; Davies, G.; Della Negra, M.; Dunne, P.; Ferguson, W.; Fulcher, J.; Futyan, D.; Hall, G.; Iles, G.; Jarvis, M.; Karapostoli, G.; Kenzie, M.; Lane, R.; Lucas, R.; Lyons, L.; Magnan, A.-M.; Malik, S.; Mathias, B.; Nash, J.; Nikitenko, A.; Pela, J.; Pesaresi, M.; Petridis, K.; Raymond, D. M.; Rogerson, S.; Rose, A.; Seez, C.; Sharp, P.; Tapper, A.; Vazquez Acosta, M.; Virdee, T.; Zenz, S. C.; Cole, J. E.; Hobson, P. R.; Khan, A.; Kyberd, P.; Leggat, D.; Leslie, D.; Reid, I. D.; Symonds, P.; Teodorescu, L.; Turner, M.; Dittmann, J.; Hatakeyama, K.; Kasmi, A.; Liu, H.; Scarborough, T.; Wu, Z.; Charaf, O.; Cooper, S. I.; Henderson, C.; Rumerio, P.; Avetisyan, A.; Bose, T.; Fantasia, C.; Lawson, P.; Richardson, C.; Rohlf, J.; St. John, J.; Sulak, L.; Alimena, J.; Berry, E.; Bhattacharya, S.; Christopher, G.; Cutts, D.; Demiragli, Z.; Dhingra, N.; Ferapontov, A.; Garabedian, A.; Heintz, U.; Kukartsev, G.; Laird, E.; Landsberg, G.; Luk, M.; Narain, M.; Segala, M.; Sinthuprasith, T.; Speer, T.; Swanson, J.; Breedon, R.; Breto, G.; Calderon De La Barca Sanchez, M.; Chauhan, S.; Chertok, M.; Conway, J.; Conway, R.; Cox, P. T.; Erbacher, R.; Gardner, M.; Ko, W.; Lander, R.; Mulhearn, M.; Pellett, D.; Pilot, J.; Ricci-Tam, F.; Shalhout, S.; Smith, J.; Squires, M.; Stolp, D.; Tripathi, M.; Wilbur, S.; Yohay, R.; Cousins, R.; Everaerts, P.; Farrell, C.; Hauser, J.; Ignatenko, M.; Rakness, G.; Takasugi, E.; Valuev, V.; Weber, M.; Burt, K.; Clare, R.; Ellison, J.; Gary, J. W.; Hanson, G.; Heilman, J.; Ivova Rikova, M.; Jandir, P.; Kennedy, E.; Lacroix, F.; Long, O. R.; Luthra, A.; Malberti, M.; Olmedo Negrete, M.; Shrinivas, A.; Sumowidagdo, S.; Wimpenny, S.; Branson, J. G.; Cerati, G. B.; Cittolin, S.; D'Agnolo, R. T.; Holzner, A.; Kelley, R.; Klein, D.; Letts, J.; Macneill, I.; Olivito, D.; Padhi, S.; Palmer, C.; Pieri, M.; Sani, M.; Sharma, V.; Simon, S.; Tadel, M.; Tu, Y.; Vartak, A.; Welke, C.; Würthwein, F.; Yagil, A.; Barge, D.; Bradmiller-Feld, J.; Campagnari, C.; Danielson, T.; Dishaw, A.; Dutta, V.; Flowers, K.; Franco Sevilla, M.; Geffert, P.; George, C.; Golf, F.; Gouskos, L.; Incandela, J.; Justus, C.; Mccoll, N.; Richman, J.; Stuart, D.; To, W.; West, C.; Yoo, J.; Apresyan, A.; Bornheim, A.; Bunn, J.; Chen, Y.; Duarte, J.; Mott, A.; Newman, H. B.; Pena, C.; Pierini, M.; Spiropulu, M.; Vlimant, J. R.; Wilkinson, R.; Xie, S.; Zhu, R. Y.; Azzolini, V.; Calamba, A.; Carlson, B.; Ferguson, T.; Iiyama, Y.; Paulini, M.; Russ, J.; Vogel, H.; Vorobiev, I.; Cumalat, J. P.; Ford, W. T.; Gaz, A.; Krohn, M.; Luiggi Lopez, E.; Nauenberg, U.; Smith, J. G.; Stenson, K.; Wagner, S. R.; Alexander, J.; Chatterjee, A.; Chaves, J.; Chu, J.; Dittmer, S.; Eggert, N.; Mirman, N.; Nicolas Kaufman, G.; Patterson, J. R.; Ryd, A.; Salvati, E.; Skinnari, L.; Sun, W.; Teo, W. D.; Thom, J.; Thompson, J.; Tucker, J.; Weng, Y.; Winstrom, L.; Wittich, P.; Winn, D.; Abdullin, S.; Albrow, M.; Anderson, J.; Apollinari, G.; Bauerdick, L. A. T.; Beretvas, A.; Berryhill, J.; Bhat, P. C.; Bolla, G.; Burkett, K.; Butler, J. N.; Cheung, H. W. K.; Chlebana, F.; Cihangir, S.; Elvira, V. D.; Fisk, I.; Freeman, J.; Gottschalk, E.; Gray, L.; Green, D.; Grünendahl, S.; Gutsche, O.; Hanlon, J.; Hare, D.; Harris, R. M.; Hirschauer, J.; Hooberman, B.; Jindariani, S.; Johnson, M.; Joshi, U.; Klima, B.; Kreis, B.; Kwan, S.; Linacre, J.; Lincoln, D.; Lipton, R.; Liu, T.; Lykken, J.; Maeshima, K.; Marraffino, J. M.; Martinez Outschoorn, V. I.; Maruyama, S.; Mason, D.; McBride, P.; Merkel, P.; Mishra, K.; Mrenna, S.; Nahn, S.; Newman-Holmes, C.; O'Dell, V.; Prokofyev, O.; Sexton-Kennedy, E.; Sharma, S.; Soha, A.; Spalding, W. J.; Spiegel, L.; Taylor, L.; Tkaczyk, S.; Tran, N. V.; Uplegger, L.; Vaandering, E. W.; Vidal, R.; Whitbeck, A.; Whitmore, J.; Yang, F.; Acosta, D.; Avery, P.; Bortignon, P.; Bourilkov, D.; Carver, M.; Curry, D.; Das, S.; De Gruttola, M.; Di Giovanni, G. P.; Field, R. D.; Fisher, M.; Furic, I. K.; Hugon, J.; Konigsberg, J.; Korytov, A.; Kypreos, T.; Low, J. F.; Matchev, K.; Mei, H.; Milenovic, P.; Mitselmakher, G.; Muniz, L.; Rinkevicius, A.; Shchutska, L.; Snowball, M.; Sperka, D.; Yelton, J.; Zakaria, M.; Hewamanage, S.; Linn, S.; Markowitz, P.; Martinez, G.; Rodriguez, J. L.; Adams, T.; Askew, A.; Bochenek, J.; Diamond, B.; Haas, J.; Hagopian, S.; Hagopian, V.; Johnson, K. F.; Prosper, H.; Veeraraghavan, V.; Weinberg, M.; Baarmand, M. M.; Hohlmann, M.; Kalakhety, H.; Yumiceva, F.; Adams, M. R.; Apanasevich, L.; Berry, D.; Betts, R. R.; Bucinskaite, I.; Cavanaugh, R.; Evdokimov, O.; Gauthier, L.; Gerber, C. E.; Hofman, D. J.; Kurt, P.; O'Brien, C.; Sandoval Gonzalez, I. D.; Silkworth, C.; Turner, P.; Varelas, N.; Bilki, B.; Clarida, W.; Dilsiz, K.; Haytmyradov, M.; Merlo, J.-P.; Mermerkaya, H.; Mestvirishvili, A.; Moeller, A.; Nachtman, J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Rahmat, R.; Sen, S.; Tan, P.; Tiras, E.; Wetzel, J.; Yi, K.; Anderson, I.; Barnett, B. A.; Blumenfeld, B.; Bolognesi, S.; Fehling, D.; Gritsan, A. V.; Maksimovic, P.; Martin, C.; Swartz, M.; Baringer, P.; Bean, A.; Benelli, G.; Bruner, C.; Gray, J.; Kenny, R. P.; Majumder, D.; Malek, M.; Murray, M.; Noonan, D.; Sanders, S.; Sekaric, J.; Stringer, R.; Wang, Q.; Wood, J. S.; Chakaberia, I.; Ivanov, A.; Kaadze, K.; Khalil, S.; Makouski, M.; Maravin, Y.; Saini, L. K.; Skhirtladze, N.; Svintradze, I.; Gronberg, J.; Lange, D.; Rebassoo, F.; Wright, D.; Baden, A.; Belloni, A.; Calvert, B.; Eno, S. C.; Gomez, J. A.; Hadley, N. J.; Kellogg, R. G.; Kolberg, T.; Lu, Y.; Mignerey, A. C.; Pedro, K.; Skuja, A.; Tonjes, M. B.; Tonwar, S. C.; Apyan, A.; Barbieri, R.; Busza, W.; Cali, I. A.; Chan, M.; Di Matteo, L.; Gomez Ceballos, G.; Goncharov, M.; Gulhan, D.; Klute, M.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; Paus, C.; Ralph, D.; Roland, C.; Roland, G.; Stephans, G. S. F.; Sumorok, K.; Velicanu, D.; Veverka, J.; Wyslouch, B.; Yang, M.; Zanetti, M.; Zhukova, V.; Dahmes, B.; Gude, A.; Kao, S. C.; Klapoetke, K.; Kubota, Y.; Mans, J.; Nourbakhsh, S.; Pastika, N.; Rusack, R.; Singovsky, A.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bloom, K.; Bose, S.; Claes, D. R.; Dominguez, A.; Gonzalez Suarez, R.; Keller, J.; Knowlton, D.; Kravchenko, I.; Lazo-Flores, J.; Meier, F.; Ratnikov, F.; Snow, G. R.; Zvada, M.; Dolen, J.; Godshalk, A.; Iashvili, I.; Kharchilava, A.; Kumar, A.; Rappoccio, S.; Alverson, G.; Barberis, E.; Baumgartel, D.; Chasco, M.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Trocino, D.; Wang, R.-J.; Wood, D.; Zhang, J.; Hahn, K. A.; Kubik, A.; Mucia, N.; Odell, N.; Pollack, B.; Pozdnyakov, A.; Schmitt, M.; Stoynev, S.; Sung, K.; Velasco, M.; Won, S.; Brinkerhoff, A.; Chan, K. M.; Drozdetskiy, A.; Hildreth, M.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Lynch, S.; Marinelli, N.; Musienko, Y.; Pearson, T.; Planer, M.; Ruchti, R.; Smith, G.; Valls, N.; Wayne, M.; Wolf, M.; Woodard, A.; Antonelli, L.; Brinson, J.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Hart, A.; Hill, C.; Hughes, R.; Kotov, K.; Ling, T. Y.; Luo, W.; Puigh, D.; Rodenburg, M.; Winer, B. L.; Wolfe, H.; Wulsin, H. W.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Koay, S. A.; Lujan, P.; Marlow, D.; Medvedeva, T.; Mooney, M.; Olsen, J.; Piroué, P.; Quan, X.; Saka, H.; Stickland, D.; Tully, C.; Werner, J. S.; Zuranski, A.; Brownson, E.; Malik, S.; Mendez, H.; Ramirez Vargas, J. E.; Barnes, V. E.; Benedetti, D.; Bortoletto, D.; De Mattia, M.; Gutay, L.; Hu, Z.; Jha, M. K.; Jones, M.; Jung, K.; Kress, M.; Leonardo, N.; Miller, D. H.; Neumeister, N.; Radburn-Smith, B. C.; Shi, X.; Shipsey, I.; Silvers, D.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Zablocki, J.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Ecklund, K. M.; Geurts, F. J. M.; Li, W.; Michlin, B.; Padley, B. P.; Redjimi, R.; Roberts, J.; Zabel, J.; Betchart, B.; Bodek, A.; Covarelli, R.; de Barbaro, P.; Demina, R.; Eshaq, Y.; Ferbel, T.; Garcia-Bellido, A.; Goldenzweig, P.; Han, J.; Harel, A.; Hindrichs, O.; Khukhunaishvili, A.; Korjenevski, S.; Petrillo, G.; Vishnevskiy, D.; Ciesielski, R.; Demortier, L.; Goulianos, K.; Mesropian, C.; Arora, S.; Barker, A.; Chou, J. P.; Contreras-Campana, C.; Contreras-Campana, E.; Duggan, D.; Ferencek, D.; Gershtein, Y.; Gray, R.; Halkiadakis, E.; Hidas, D.; Kaplan, S.; Lath, A.; Panwalkar, S.; Park, M.; Patel, R.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Rose, K.; Spanier, S.; York, A.; Bouhali, O.; Castaneda Hernandez, A.; Eusebi, R.; Flanagan, W.; Gilmore, J.; Kamon, T.; Khotilovich, V.; Krutelyov, V.; Montalvo, R.; Osipenkov, I.; Pakhotin, Y.; Perloff, A.; Roe, J.; Rose, A.; Safonov, A.; Suarez, I.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Kovitanggoon, K.; Kunori, S.; Lee, S. W.; Libeiro, T.; Volobouev, I.; Appelt, E.; Delannoy, A. G.; Greene, S.; Gurrola, A.; Johns, W.; Maguire, C.; Mao, Y.; Melo, A.; Sharma, M.; Sheldon, P.; Snook, B.; Tuo, S.; Velkovska, J.; Arenton, M. W.; Boutle, S.; Cox, B.; Francis, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Lin, C.; Neu, C.; Wood, J.; Clarke, C.; Harr, R.; Karchin, P. E.; Kottachchi Kankanamge Don, C.; Lamichhane, P.; Sturdy, J.; Belknap, D. A.; Carlsmith, D.; Cepeda, M.; Dasu, S.; Dodd, L.; Duric, S.; Friis, E.; Hall-Wilton, R.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Lazaridis, C.; Levine, A.; Loveless, R.; Mohapatra, A.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ross, I.; Sarangi, T.; Savin, A.; Smith, W. H.; Taylor, D.; Vuosalo, C.; Woods, N.

    2015-04-01

    The cross section for the production of Z γ in proton-proton collisions at 8 TeV is measured based on data collected by the CMS experiment at the LHC corresponding to an integrated luminosity of 19.5 fb-1. Events with an oppositely-charged pair of muons or electrons together with an isolated photon are selected. The differential cross section as a function of the photon transverse momentum is measured inclusively and exclusively, where the exclusive selection applies a veto on central jets. The observed cross sections are compatible with the expectations of next-to-next-to-leading-order quantum chromodynamics. Limits on anomalous triple gauge couplings of ZZ γ and Z γγ are set that improve on previous experimental results obtained with the charged lepton decay modes of the Z boson. [Figure not available: see fulltext.

  12. Characterization of chiral amino acids from different milk origins using ultra-performance liquid chromatography coupled to ion-mobility mass spectrometry

    NASA Astrophysics Data System (ADS)

    Tian, He; Zheng, Nan; Li, Songli; Zhang, Yangdong; Zhao, Shengguo; Wen, Fang; Wang, Jiaqi

    2017-04-01

    Milk contains free amino acids (AAs) that play essential roles in maintaining the growth and health of infants, and D-AA isomers are increasingly being recognized as important signalling molecules. However, there are no studies of the different characteristics of chiral AA (C-AA) from different milk origins. Here, UPLC coupled to ion-mobility high-resolution MS (IM-HRMS) was employed to characterize 18 pairs of C-AAs in human, cow, yak, buffalo, goat, and camel milk. The results proved that milk origins can be differentiated based on the D- to L- AA ratio-based projection scores by principal component analysis. The present study gives a deeper understanding of the D- to L- AA ratio underlying the biological functions of different animal milks, and provide a new strategy for the study of AA metabolic pathways.

  13. Course 4: Density Functional Theory, Methods, Techniques, and Applications

    NASA Astrophysics Data System (ADS)

    Chrétien, S.; Salahub, D. R.

    Contents 1 Introduction 2 Density functional theory 2.1 Hohenberg and Kohn theorems 2.2 Levy's constrained search 2.3 Kohn-Sham method 3 Density matrices and pair correlation functions 4 Adiabatic connection or coupling strength integration 5 Comparing and constrasting KS-DFT and HF-CI 6 Preparing new functionals 7 Approximate exchange and correlation functionals 7.1 The Local Spin Density Approximation (LSDA) 7.2 Gradient Expansion Approximation (GEA) 7.3 Generalized Gradient Approximation (GGA) 7.4 meta-Generalized Gradient Approximation (meta-GGA) 7.5 Hybrid functionals 7.6 The Optimized Effective Potential method (OEP) 7.7 Comparison between various approximate functionals 8 LAP correlation functional 9 Solving the Kohn-Sham equations 9.1 The Kohn-Sham orbitals 9.2 Coulomb potential 9.3 Exchange-correlation potential 9.4 Core potential 9.5 Other choices and sources of error 9.6 Functionality 10 Applications 10.1 Ab initio molecular dynamics for an alanine dipeptide model 10.2 Transition metal clusters: The ecstasy, and the agony... 10.3 The conversion of acetylene to benzene on Fe clusters 11 Conclusions

  14. Capturing the radical ion-pair intermediate in DNA guanine oxidation

    PubMed Central

    Jie, Jialong; Liu, Kunhui; Wu, Lidan; Zhao, Hongmei; Song, Di; Su, Hongmei

    2017-01-01

    Although the radical ion pair has been frequently invoked as a key intermediate in DNA oxidative damage reactions and photoinduced electron transfer processes, the unambiguous detection and characterization of this species remain formidable and unresolved due to its extremely unstable nature and low concentration. We use the strategy that, at cryogenic temperatures, the transient species could be sufficiently stabilized to be detectable spectroscopically. By coupling the two techniques (the cryogenic stabilization and the time-resolved laser flash photolysis spectroscopy) together, we are able to capture the ion-pair transient G+•⋯Cl− in the chlorine radical–initiated DNA guanine (G) oxidation reaction, and provide direct evidence to ascertain the intricate type of addition/charge separation mechanism underlying guanine oxidation. The unique spectral signature of the radical ion-pair G+•⋯Cl− is identified, revealing a markedly intense absorption feature peaking at 570 nm that is distinctive from G+• alone. Moreover, the ion-pair spectrum is found to be highly sensitive to the protonation equilibria within guanine-cytosine base pair (G:C), which splits into two resolved bands at 480 and 610 nm as the acidic proton transfers along the central hydrogen bond from G+• to C. We thus use this exquisite sensitivity to track the intrabase-pair proton transfer dynamics in the double-stranded DNA oligonucleotides, which is of critical importance for the description of the proton-coupled charge transfer mechanisms in DNA. PMID:28630924

  15. An experimental and theoretical study of the valence shell photoelectron spectra of 2-chloropyridine and 3-chloropyridine

    NASA Astrophysics Data System (ADS)

    Holland, D. M. P.; Powis, I.; Trofimov, A. B.; Menzies, R. C.; Potts, A. W.; Karlsson, L.; Badsyuk, I. L.; Moskovskaya, T. E.; Gromov, E. V.; Schirmer, J.

    2017-10-01

    The valence shell photoelectron spectra of 2-chloropyridine and 3-chloropyridine have been studied both experimentally and theoretically. Synchrotron radiation has been employed to record angle resolved photoelectron spectra in the photon energy range 20-100 eV, and these have enabled anisotropy parameters and branching ratios to be derived. The experimental results have been compared with theoretical predictions obtained using the continuum multiple scattering Xα approach. This comparison shows that the anisotropy parameter associated with the nominally chlorine lone-pair orbital lying in the molecular plane is strongly affected by the atomic Cooper minimum. In contrast, the photoionization dynamics of the second lone-pair orbital, orientated perpendicular to the molecular plane, seem relatively unaffected by this atomic phenomenon. The outer valence ionization has been studied theoretically using the third-order algebraic-diagrammatic construction (ADC(3)) approximation scheme for the one-particle Green's function, the outer valence Green's function method, and the equation-of-motion (EOM) coupled cluster (CC) theory at the level of the EOM-IP-CCSD and EOM-EE-CC3 models. The convergence of the results to the complete basis set limit has been investigated. The ADC(3) method has been employed to compute the complete valence shell ionization spectra of 2-chloropyridine and 3-chloropyridine. The relaxation mechanism for ionization of the nitrogen σ-type lone-pair orbital (σN LP) has been found to be different to that for the corresponding chlorine lone-pair (σCl LP). For the σN LP orbital, π-π* excitations play the main role in the screening of the lone-pair hole. In contrast, excitations localized at the chlorine site involving the chlorine πCl LP lone-pair and the Cl 4p Rydberg orbital are the most important for the σCl LP orbital. The calculated photoelectron spectra have allowed assignments to be proposed for most of the structure observed in the experimental spectra. The theoretical work also highlights the formation of satellite states, due to the breakdown of the single particle model of ionization, in the inner valence region.

  16. An experimental and theoretical study of the valence shell photoelectron spectra of 2-chloropyridine and 3-chloropyridine.

    PubMed

    Holland, D M P; Powis, I; Trofimov, A B; Menzies, R C; Potts, A W; Karlsson, L; Badsyuk, I L; Moskovskaya, T E; Gromov, E V; Schirmer, J

    2017-10-28

    The valence shell photoelectron spectra of 2-chloropyridine and 3-chloropyridine have been studied both experimentally and theoretically. Synchrotron radiation has been employed to record angle resolved photoelectron spectra in the photon energy range 20-100 eV, and these have enabled anisotropy parameters and branching ratios to be derived. The experimental results have been compared with theoretical predictions obtained using the continuum multiple scattering Xα approach. This comparison shows that the anisotropy parameter associated with the nominally chlorine lone-pair orbital lying in the molecular plane is strongly affected by the atomic Cooper minimum. In contrast, the photoionization dynamics of the second lone-pair orbital, orientated perpendicular to the molecular plane, seem relatively unaffected by this atomic phenomenon. The outer valence ionization has been studied theoretically using the third-order algebraic-diagrammatic construction (ADC(3)) approximation scheme for the one-particle Green's function, the outer valence Green's function method, and the equation-of-motion (EOM) coupled cluster (CC) theory at the level of the EOM-IP-CCSD and EOM-EE-CC3 models. The convergence of the results to the complete basis set limit has been investigated. The ADC(3) method has been employed to compute the complete valence shell ionization spectra of 2-chloropyridine and 3-chloropyridine. The relaxation mechanism for ionization of the nitrogen σ-type lone-pair orbital (σ N LP ) has been found to be different to that for the corresponding chlorine lone-pair (σ Cl LP ). For the σ N LP orbital, π-π* excitations play the main role in the screening of the lone-pair hole. In contrast, excitations localized at the chlorine site involving the chlorine π Cl LP lone-pair and the Cl 4p Rydberg orbital are the most important for the σ Cl LP orbital. The calculated photoelectron spectra have allowed assignments to be proposed for most of the structure observed in the experimental spectra. The theoretical work also highlights the formation of satellite states, due to the breakdown of the single particle model of ionization, in the inner valence region.

  17. Search for pair-produced vectorlike B quarks in proton-proton collisions at √{s }=8 TeV

    NASA Astrophysics Data System (ADS)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Asilar, E.; Bergauer, T.; Brandstetter, J.; Brondolin, E.; Dragicevic, M.; Erö, J.; Flechl, M.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Knünz, V.; König, A.; Krammer, M.; Krätschmer, I.; Liko, D.; Matsushita, T.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schieck, J.; Schöfbeck, R.; Strauss, J.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Cornelis, T.; de Wolf, E. A.; Janssen, X.; Knutsson, A.; Lauwers, J.; Luyckx, S.; Ochesanu, S.; Rougny, R.; van de Klundert, M.; van Haevermaet, H.; van Mechelen, P.; van Remortel, N.; van Spilbeeck, A.; Abu Zeid, S.; Blekman, F.; D'Hondt, J.; Daci, N.; de Bruyn, I.; Deroover, K.; Heracleous, N.; Keaveney, J.; Lowette, S.; Moreels, L.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; van Doninck, W.; van Mulders, P.; van Onsem, G. P.; van Parijs, I.; Barria, P.; Caillol, C.; Clerbaux, B.; de Lentdecker, G.; Delannoy, H.; Dobur, D.; Fasanella, G.; Favart, L.; Gay, A. P. R.; Grebenyuk, A.; Lenzi, T.; Léonard, A.; Maerschalk, T.; Mohammadi, A.; Perniè, L.; Randle-Conde, A.; Reis, T.; Seva, T.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Yonamine, R.; Zenoni, F.; Zhang, F.; Beernaert, K.; Benucci, L.; Cimmino, A.; Crucy, S.; Fagot, A.; Garcia, G.; Gul, M.; McCartin, J.; Ocampo Rios, A. A.; Poyraz, D.; Ryckbosch, D.; Salva, S.; Sigamani, M.; Strobbe, N.; Tytgat, M.; van Driessche, W.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bondu, O.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; da Silveira, G. G.; Delaere, C.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Mertens, A.; Nuttens, C.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Beliy, N.; Caebergs, T.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Dos Reis Martins, T.; Hensel, C.; Mora Herrera, C.; Moraes, A.; Pol, M. E.; Rebello Teles, P.; Belchior Batista Das Chagas, E.; Carvalho, W.; Chinellato, J.; Custódio, A.; da Costa, E. M.; de Jesus Damiao, D.; de Oliveira Martins, C.; Fonseca de Souza, S.; Huertas Guativa, L. M.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado da Silva, W. L.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Ahuja, S.; Bernardes, C. A.; de Souza Santos, A.; Dogra, S.; Tomei, T. R. Fernandez Perez; Gregores, E. M.; Mercadante, P. G.; Moon, C. S.; Novaes, S. F.; Padula, Sandra S.; Romero Abad, D.; Ruiz Vargas, J. C.; Aleksandrov, A.; Genchev, V.; Hadjiiska, R.; Iaydjiev, P.; Marinov, A.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Litov, L.; Pavlov, B.; Petkov, P.; Ahmad, M.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Cheng, T.; Du, R.; Jiang, C. 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A.; Radi, A.; Sayed, A.; Calpas, B.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Veelken, C.; Eerola, P.; Pekkanen, J.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Machet, M.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Zghiche, A.; Baffioni, S.; Beaudette, F.; Busson, P.; Cadamuro, L.; Chapon, E.; Charlot, C.; Dahms, T.; Davignon, O.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Lisniak, S.; Mastrolorenzo, L.; Miné, P.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Ortona, G.; Paganini, P.; Regnard, S.; Salerno, R.; Sauvan, J. 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F.; Verlage, T.; Weber, H.; Wittmer, B.; Zhukov, V.; Ata, M.; Brodski, M.; Dietz-Laursonn, E.; Duchardt, D.; Endres, M.; Erdmann, M.; Erdweg, S.; Esch, T.; Fischer, R.; Güth, A.; Hebbeker, T.; Heidemann, C.; Hoepfner, K.; Klingebiel, D.; Knutzen, S.; Kreuzer, P.; Merschmeyer, M.; Meyer, A.; Millet, P.; Olschewski, M.; Padeken, K.; Papacz, P.; Pook, T.; Radziej, M.; Reithler, H.; Rieger, M.; Scheuch, F.; Sonnenschein, L.; Teyssier, D.; Thüer, S.; Cherepanov, V.; Erdogan, Y.; Flügge, G.; Geenen, H.; Geisler, M.; Haj Ahmad, W.; Hoehle, F.; Kargoll, B.; Kress, T.; Kuessel, Y.; Künsken, A.; Lingemann, J.; Nehrkorn, A.; Nowack, A.; Nugent, I. M.; Pistone, C.; Pooth, O.; Stahl, A.; Aldaya Martin, M.; Asin, I.; Bartosik, N.; Behnke, O.; Behrens, U.; Bell, A. J.; Borras, K.; Burgmeier, A.; Cakir, A.; Calligaris, L.; Campbell, A.; Choudhury, S.; Costanza, F.; Diez Pardos, C.; Dolinska, G.; Dooling, S.; Dorland, T.; Eckerlin, G.; Eckstein, D.; Eichhorn, T.; Flucke, G.; Gallo, E.; Garay Garcia, J.; Geiser, A.; Gizhko, A.; Gunnellini, P.; Hauk, J.; Hempel, M.; Jung, H.; Kalogeropoulos, A.; Karacheban, O.; Kasemann, M.; Katsas, P.; Kieseler, J.; Kleinwort, C.; Korol, I.; Lange, W.; Leonard, J.; Lipka, K.; Lobanov, A.; Lohmann, W.; Mankel, R.; Marfin, I.; Melzer-Pellmann, I.-A.; Meyer, A. B.; Mittag, G.; Mnich, J.; Mussgiller, A.; Naumann-Emme, S.; Nayak, A.; Ntomari, E.; Perrey, H.; Pitzl, D.; Placakyte, R.; Raspereza, A.; Ribeiro Cipriano, P. M.; Roland, B.; Sahin, M. Ö.; Salfeld-Nebgen, J.; Saxena, P.; Schoerner-Sadenius, T.; Schröder, M.; Seitz, C.; Spannagel, S.; Trippkewitz, K. D.; Wissing, C.; Blobel, V.; Centis Vignali, M.; Draeger, A. R.; Erfle, J.; Garutti, E.; Goebel, K.; Gonzalez, D.; Görner, M.; Haller, J.; Hoffmann, M.; Höing, R. S.; Junkes, A.; Klanner, R.; Kogler, R.; Lapsien, T.; Lenz, T.; Marchesini, I.; Marconi, D.; Nowatschin, D.; Ott, J.; Pantaleo, F.; Peiffer, T.; Perieanu, A.; Pietsch, N.; Poehlsen, J.; Rathjens, D.; Sander, C.; Schettler, H.; Schleper, P.; Schlieckau, E.; Schmidt, A.; Schwandt, J.; Seidel, M.; Sola, V.; Stadie, H.; Steinbrück, G.; Tholen, H.; Troendle, D.; Usai, E.; Vanelderen, L.; Vanhoefer, A.; Akbiyik, M.; Amstutz, C.; Barth, C.; Baus, C.; Berger, J.; Beskidt, C.; Böser, C.; Butz, E.; Caspart, R.; Chwalek, T.; Colombo, F.; de Boer, W.; Descroix, A.; Dierlamm, A.; Eber, R.; Feindt, M.; Fink, S.; Fischer, M.; Frensch, F.; Freund, B.; Friese, R.; Funke, D.; Giffels, M.; Gilbert, A.; Haitz, D.; Harbaum, T.; Harrendorf, M. A.; Hartmann, F.; Husemann, U.; Kassel, F.; Katkov, I.; Kornmayer, A.; Kudella, S.; Lobelle Pardo, P.; Maier, B.; Mildner, H.; Mozer, M. U.; Müller, T.; Müller, Th.; Plagge, M.; Printz, M.; Quast, G.; Rabbertz, K.; Röcker, S.; Roscher, F.; Shvetsov, I.; Sieber, G.; Simonis, H. J.; Stober, F. M.; Ulrich, R.; Wagner-Kuhr, J.; Wayand, S.; Weiler, T.; Williamson, S.; Wöhrmann, C.; Wolf, R.; Anagnostou, G.; Daskalakis, G.; Geralis, T.; Giakoumopoulou, V. A.; Kyriakis, A.; Loukas, D.; Markou, A.; Psallidas, A.; Topsis-Giotis, I.; Agapitos, A.; Kesisoglou, S.; Panagiotou, A.; Saoulidou, N.; Tziaferi, E.; Evangelou, I.; Flouris, G.; Foudas, C.; Kokkas, P.; Loukas, N.; Manthos, N.; Papadopoulos, I.; Paradas, E.; Strologas, J.; Bencze, G.; Hajdu, C.; Hazi, A.; Hidas, P.; Horvath, D.; Sikler, F.; Veszpremi, V.; Vesztergombi, G.; Zsigmond, A. J.; Beni, N.; Czellar, S.; Karancsi, J.; Molnar, J.; Szillasi, Z.; Bartók, M.; Makovec, A.; Raics, P.; Trocsanyi, Z. L.; Ujvari, B.; Mal, P.; Mandal, K.; Sahoo, N.; Swain, S. K.; Bansal, S.; Beri, S. B.; Bhatnagar, V.; Chawla, R.; Gupta, R.; Bhawandeep, U.; Kalsi, A. K.; Kaur, A.; Kaur, M.; Kumar, R.; Mehta, A.; Mittal, M.; Nishu, N.; Singh, J. B.; Walia, G.; Kumar, Ashok; Kumar, Arun; Bhardwaj, A.; Choudhary, B. C.; Garg, R. B.; Kumar, A.; Malhotra, S.; Naimuddin, M.; Ranjan, K.; Sharma, R.; Sharma, V.; Banerjee, S.; Bhattacharya, S.; Chatterjee, K.; Dey, S.; Dutta, S.; Jain, Sa.; Jain, Sh.; Khurana, R.; Majumdar, N.; Modak, A.; Mondal, K.; Mukherjee, S.; Mukhopadhyay, S.; Roy, A.; Roy, D.; Roy Chowdhury, S.; Sarkar, S.; Sharan, M.; Abdulsalam, A.; Chudasama, R.; Dutta, D.; Jha, V.; Kumar, V.; Mohanty, A. K.; Pant, L. M.; Shukla, P.; Topkar, A.; Aziz, T.; Banerjee, S.; Bhowmik, S.; Chatterjee, R. M.; Dewanjee, R. K.; Dugad, S.; Ganguly, S.; Ghosh, S.; Guchait, M.; Gurtu, A.; Kole, G.; Kumar, S.; Mahakud, B.; Maity, M.; Majumder, G.; Mazumdar, K.; Mitra, S.; Mohanty, G. B.; Parida, B.; Sarkar, T.; Sudhakar, K.; Sur, N.; Sutar, B.; Wickramage, N.; Sharma, S.; Bakhshiansohi, H.; Behnamian, H.; Etesami, S. 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M.; Lanza, G.; Lista, L.; Meola, S.; Merola, M.; Paolucci, P.; Sciacca, C.; Thyssen, F.; Azzi, P.; Bacchetta, N.; Bisello, D.; Branca, A.; Carlin, R.; Carvalho Antunes de Oliveira, A.; Checchia, P.; Dall'Osso, M.; Dorigo, T.; Dosselli, U.; Gasparini, F.; Gasparini, U.; Gozzelino, A.; Kanishchev, K.; Lacaprara, S.; Margoni, M.; Meneguzzo, A. T.; Pazzini, J.; Pozzobon, N.; Simonetto, F.; Torassa, E.; Tosi, M.; Ventura, S.; Zanetti, M.; Zotto, P.; Zucchetta, A.; Zumerle, G.; Braghieri, A.; Gabusi, M.; Magnani, A.; Ratti, S. P.; Re, V.; Riccardi, C.; Salvini, P.; Vai, I.; Vitulo, P.; Alunni Solestizi, L.; Biasini, M.; Bilei, G. M.; Ciangottini, D.; Fanò, L.; Lariccia, P.; Mantovani, G.; Menichelli, M.; Saha, A.; Santocchia, A.; Spiezia, A.; Androsov, K.; Azzurri, P.; Bagliesi, G.; Bernardini, J.; Boccali, T.; Broccolo, G.; Castaldi, R.; Ciocci, M. A.; Dell'Orso, R.; Donato, S.; Fedi, G.; Foà, L.; Giassi, A.; Grippo, M. T.; Ligabue, F.; Lomtadze, T.; Martini, L.; Messineo, A.; Palla, F.; Rizzi, A.; Savoy-Navarro, A.; Serban, A. T.; Spagnolo, P.; Squillacioti, P.; Tenchini, R.; Tonelli, G.; Venturi, A.; Verdini, P. G.; Barone, L.; Cavallari, F.; D'Imperio, G.; Del Re, D.; Diemoz, M.; Gelli, S.; Jorda, C.; Longo, E.; Margaroli, F.; Meridiani, P.; Micheli, F.; Organtini, G.; Paramatti, R.; Preiato, F.; Rahatlou, S.; Rovelli, C.; Santanastasio, F.; Traczyk, P.; Amapane, N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bellan, R.; Biino, C.; Cartiglia, N.; Costa, M.; Covarelli, R.; de Remigis, P.; Degano, A.; Demaria, N.; Finco, L.; Mariotti, C.; Maselli, S.; Mazza, G.; Migliore, E.; Monaco, V.; Monteil, E.; Musich, M.; Obertino, M. M.; Pacher, L.; Pastrone, N.; Pelliccioni, M.; Pinna Angioni, G. L.; Ravera, F.; Romero, A.; Ruspa, M.; Sacchi, R.; Solano, A.; Staiano, A.; Belforte, S.; Candelise, V.; Casarsa, M.; Cossutti, F.; Della Ricca, G.; Gobbo, B.; La Licata, C.; Marone, M.; Schizzi, A.; Umer, T.; Zanetti, A.; Chang, S.; Kropivnitskaya, A.; Nam, S. K.; Kim, D. H.; Kim, G. N.; Kim, M. S.; Kong, D. J.; Lee, S.; Oh, Y. D.; Sakharov, A.; Son, D. C.; Brochero Cifuentes, J. A.; Kim, H.; Kim, T. J.; Ryu, M. S.; Song, S.; Choi, S.; Go, Y.; Gyun, D.; Hong, B.; Jo, M.; Kim, H.; Kim, Y.; Lee, B.; Lee, K.; Lee, K. S.; Lee, S.; Park, S. K.; Roh, Y.; Yoo, H. D.; Choi, M.; Kim, J. H.; Lee, J. S. H.; Park, I. C.; Ryu, G.; Choi, Y.; Choi, Y. K.; Goh, J.; Kim, D.; Kwon, E.; Lee, J.; Yu, I.; Juodagalvis, A.; Vaitkus, J.; Ahmed, I.; Ibrahim, Z. A.; Komaragiri, J. R.; Md Ali, M. A. B.; Mohamad Idris, F.; Wan Abdullah, W. A. T.; Casimiro Linares, E.; Castilla-Valdez, H.; de La Cruz-Burelo, E.; Heredia-de La Cruz, I.; Hernandez-Almada, A.; Lopez-Fernandez, R.; Sanchez-Hernandez, A.; Carrillo Moreno, S.; Vazquez Valencia, F.; Carpinteyro, S.; Pedraza, I.; Salazar Ibarguen, H. A.; Morelos Pineda, A.; Krofcheck, D.; Butler, P. H.; Reucroft, S.; Ahmad, A.; Ahmad, M.; Hassan, Q.; Hoorani, H. R.; Khan, W. A.; Khurshid, T.; Shoaib, M.; Bialkowska, H.; Bluj, M.; Boimska, B.; Frueboes, T.; Górski, M.; Kazana, M.; Nawrocki, K.; Romanowska-Rybinska, K.; Szleper, M.; Zalewski, P.; Brona, G.; Bunkowski, K.; Doroba, K.; Kalinowski, A.; Konecki, M.; Krolikowski, J.; Misiura, M.; Olszewski, M.; Walczak, M.; Bargassa, P.; Beirão da Cruz E Silva, C.; di Francesco, A.; Faccioli, P.; Ferreira Parracho, P. G.; Gallinaro, M.; Lloret Iglesias, L.; Nguyen, F.; Rodrigues Antunes, J.; Seixas, J.; Toldaiev, O.; Vadruccio, D.; Varela, J.; Vischia, P.; Afanasiev, S.; Bunin, P.; Gavrilenko, M.; Golutvin, I.; Gorbunov, I.; Kamenev, A.; Karjavin, V.; Konoplyanikov, V.; Lanev, A.; Malakhov, A.; Matveev, V.; Moisenz, P.; Palichik, V.; Perelygin, V.; Shmatov, S.; Shulha, S.; Skatchkov, N.; Smirnov, V.; Zarubin, A.; Golovtsov, V.; Ivanov, Y.; Kim, V.; Kuznetsova, E.; Levchenko, P.; Murzin, V.; Oreshkin, V.; Smirnov, I.; Sulimov, V.; Uvarov, L.; Vavilov, S.; Vorobyev, A.; Andreev, Yu.; Dermenev, A.; Gninenko, S.; Golubev, N.; Karneyeu, A.; Kirsanov, M.; Krasnikov, N.; Pashenkov, A.; Tlisov, D.; Toropin, A.; Epshteyn, V.; Gavrilov, V.; Lychkovskaya, N.; Popov, V.; Pozdnyakov, I.; Safronov, G.; Spiridonov, A.; Vlasov, E.; Zhokin, A.; Bylinkin, A.; Andreev, V.; Azarkin, M.; Dremin, I.; Kirakosyan, M.; Leonidov, A.; Mesyats, G.; Rusakov, S. 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P.; Ford, W. T.; Gaz, A.; Jensen, F.; Johnson, A.; Krohn, M.; Mulholland, T.; Nauenberg, U.; Smith, J. G.; Stenson, K.; Wagner, S. R.; Alexander, J.; Chatterjee, A.; Chaves, J.; Chu, J.; Dittmer, S.; Eggert, N.; Mirman, N.; Nicolas Kaufman, G.; Patterson, J. R.; Rinkevicius, A.; Ryd, A.; Skinnari, L.; Soffi, L.; Sun, W.; Tan, S. M.; Teo, W. D.; Thom, J.; Thompson, J.; Tucker, J.; Weng, Y.; Wittich, P.; Abdullin, S.; Albrow, M.; Anderson, J.; Apollinari, G.; Bauerdick, L. A. T.; Beretvas, A.; Berryhill, J.; Bhat, P. C.; Bolla, G.; Burkett, K.; Butler, J. N.; Cheung, H. W. K.; Chlebana, F.; Cihangir, S.; Elvira, V. D.; Fisk, I.; Freeman, J.; Gottschalk, E.; Gray, L.; Green, D.; Grünendahl, S.; Gutsche, O.; Hanlon, J.; Hare, D.; Harris, R. M.; Hirschauer, J.; Hooberman, B.; Hu, Z.; Jindariani, S.; Johnson, M.; Joshi, U.; Jung, A. W.; Klima, B.; Kreis, B.; Kwan, S.; Lammel, S.; Linacre, J.; Lincoln, D.; Lipton, R.; Liu, T.; Lopes de Sá, R.; Lykken, J.; Maeshima, K.; Marraffino, J. 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P.; Majumder, D.; Malek, M.; Murray, M.; Noonan, D.; Sanders, S.; Stringer, R.; Wang, Q.; Wood, J. S.; Chakaberia, I.; Ivanov, A.; Kaadze, K.; Khalil, S.; Makouski, M.; Maravin, Y.; Saini, L. K.; Skhirtladze, N.; Svintradze, I.; Toda, S.; Lange, D.; Rebassoo, F.; Wright, D.; Anelli, C.; Baden, A.; Baron, O.; Belloni, A.; Calvert, B.; Eno, S. C.; Ferraioli, C.; Gomez, J. A.; Hadley, N. J.; Jabeen, S.; Kellogg, R. G.; Kolberg, T.; Kunkle, J.; Lu, Y.; Mignerey, A. C.; Pedro, K.; Shin, Y. H.; Skuja, A.; Tonjes, M. B.; Tonwar, S. C.; Apyan, A.; Barbieri, R.; Baty, A.; Bierwagen, K.; Brandt, S.; Busza, W.; Cali, I. A.; Demiragli, Z.; Di Matteo, L.; Gomez Ceballos, G.; Goncharov, M.; Gulhan, D.; Innocenti, G. M.; Klute, M.; Kovalskyi, D.; Lai, Y. S.; Lee, Y.-J.; Levin, A.; Luckey, P. D.; McGinn, C.; Niu, X.; Paus, C.; Ralph, D.; Roland, C.; Roland, G.; Stephans, G. S. F.; Sumorok, K.; Varma, M.; Velicanu, D.; Veverka, J.; Wang, J.; Wang, T. W.; Wyslouch, B.; Yang, M.; Zhukova, V.; Dahmes, B.; Finkel, A.; Gude, A.; Hansen, P.; Kalafut, S.; Kao, S. C.; Klapoetke, K.; Kubota, Y.; Lesko, Z.; Mans, J.; Nourbakhsh, S.; Ruckstuhl, N.; Rusack, R.; Tambe, N.; Turkewitz, J.; Acosta, J. G.; Oliveros, S.; Avdeeva, E.; Bloom, K.; Bose, S.; Claes, D. R.; Dominguez, A.; Fangmeier, C.; Gonzalez Suarez, R.; Kamalieddin, R.; Keller, J.; Knowlton, D.; Kravchenko, I.; Lazo-Flores, J.; Meier, F.; Monroy, J.; Ratnikov, F.; Siado, J. E.; Snow, G. R.; Alyari, M.; Dolen, J.; George, J.; Godshalk, A.; Iashvili, I.; Kaisen, J.; Kharchilava, A.; Kumar, A.; Rappoccio, S.; Alverson, G.; Barberis, E.; Baumgartel, D.; Chasco, M.; Hortiangtham, A.; Massironi, A.; Morse, D. M.; Nash, D.; Orimoto, T.; Teixeira de Lima, R.; Trocino, D.; Wang, R.-J.; Wood, D.; Zhang, J.; Hahn, K. A.; Kubik, A.; Mucia, N.; Odell, N.; Pollack, B.; Pozdnyakov, A.; Schmitt, M.; Stoynev, S.; Sung, K.; Trovato, M.; Velasco, M.; Won, S.; Brinkerhoff, A.; Dev, N.; Hildreth, M.; Jessop, C.; Karmgard, D. J.; Kellams, N.; Lannon, K.; Lynch, S.; Marinelli, N.; Meng, F.; Mueller, C.; Musienko, Y.; Pearson, T.; Planer, M.; Ruchti, R.; Smith, G.; Valls, N.; Wayne, M.; Wolf, M.; Woodard, A.; Antonelli, L.; Brinson, J.; Bylsma, B.; Durkin, L. S.; Flowers, S.; Hart, A.; Hill, C.; Hughes, R.; Kotov, K.; Ling, T. Y.; Liu, B.; Luo, W.; Puigh, D.; Rodenburg, M.; Winer, B. L.; Wulsin, H. W.; Driga, O.; Elmer, P.; Hardenbrook, J.; Hebda, P.; Koay, S. A.; Lujan, P.; Marlow, D.; Medvedeva, T.; Mooney, M.; Olsen, J.; Palmer, C.; Piroué, P.; Quan, X.; Saka, H.; Stickland, D.; Tully, C.; Werner, J. S.; Zuranski, A.; Malik, S.; Barnes, V. E.; Benedetti, D.; Bortoletto, D.; Gutay, L.; Jha, M. K.; Jones, M.; Jung, K.; Kress, M.; Leonardo, N.; Miller, D. H.; Neumeister, N.; Primavera, F.; Radburn-Smith, B. C.; Shi, X.; Shipsey, I.; Silvers, D.; Sun, J.; Svyatkovskiy, A.; Wang, F.; Xie, W.; Xu, L.; Zablocki, J.; Parashar, N.; Stupak, J.; Adair, A.; Akgun, B.; Chen, Z.; Ecklund, K. M.; Geurts, F. J. M.; Guilbaud, M.; Li, W.; Michlin, B.; Northup, M.; Padley, B. P.; Redjimi, R.; Roberts, J.; Rorie, J.; Tu, Z.; Zabel, J.; Betchart, B.; Bodek, A.; de Barbaro, P.; Demina, R.; Eshaq, Y.; Ferbel, T.; Galanti, M.; Garcia-Bellido, A.; Goldenzweig, P.; Han, J.; Harel, A.; Hindrichs, O.; Khukhunaishvili, A.; Petrillo, G.; Verzetti, M.; Demortier, L.; Arora, S.; Barker, A.; Chou, J. P.; Contreras-Campana, C.; Contreras-Campana, E.; Duggan, D.; Ferencek, D.; Gershtein, Y.; Gray, R.; Halkiadakis, E.; Hidas, D.; Hughes, E.; Kaplan, S.; Kunnawalkam Elayavalli, R.; Lath, A.; Panwalkar, S.; Park, M.; Salur, S.; Schnetzer, S.; Sheffield, D.; Somalwar, S.; Stone, R.; Thomas, S.; Thomassen, P.; Walker, M.; Foerster, M.; Riley, G.; Rose, K.; Spanier, S.; York, A.; Bouhali, O.; Castaneda Hernandez, A.; Dalchenko, M.; de Mattia, M.; Delgado, A.; Dildick, S.; Eusebi, R.; Flanagan, W.; Gilmore, J.; Kamon, T.; Krutelyov, V.; Montalvo, R.; Mueller, R.; Osipenkov, I.; Pakhotin, Y.; Patel, R.; Perloff, A.; Roe, J.; Rose, A.; Safonov, A.; Tatarinov, A.; Ulmer, K. A.; Akchurin, N.; Cowden, C.; Damgov, J.; Dragoiu, C.; Dudero, P. R.; Faulkner, J.; Kunori, S.; Lamichhane, K.; Lee, S. W.; Libeiro, T.; Undleeb, S.; Volobouev, I.; Appelt, E.; Delannoy, A. G.; Greene, S.; Gurrola, A.; Janjam, R.; Johns, W.; Maguire, C.; Mao, Y.; Melo, A.; Sheldon, P.; Snook, B.; Tuo, S.; Velkovska, J.; Xu, Q.; Arenton, M. W.; Boutle, S.; Cox, B.; Francis, B.; Goodell, J.; Hirosky, R.; Ledovskoy, A.; Li, H.; Lin, C.; Neu, C.; Wolfe, E.; Wood, J.; Xia, F.; Clarke, C.; Harr, R.; Karchin, P. E.; Kottachchi Kankanamge Don, C.; Lamichhane, P.; Sturdy, J.; Belknap, D. A.; Carlsmith, D.; Cepeda, M.; Christian, A.; Dasu, S.; Dodd, L.; Duric, S.; Friis, E.; Gomber, B.; Hall-Wilton, R.; Herndon, M.; Hervé, A.; Klabbers, P.; Lanaro, A.; Levine, A.; Long, K.; Loveless, R.; Mohapatra, A.; Ojalvo, I.; Perry, T.; Pierro, G. A.; Polese, G.; Ross, I.; Ruggles, T.; Sarangi, T.; Savin, A.; Sharma, A.; Smith, N.; Smith, W. H.; Taylor, D.; Woods, N.; Cms Collaboration

    2016-06-01

    A search for the production of a heavy B quark, having electric charge -1 /3 and vector couplings to W , Z , and H bosons, is carried out using proton-proton collision data recorded at the CERN LHC by the CMS experiment, corresponding to an integrated luminosity of 19.7 fb-1 . The B quark is assumed to be pair produced and to decay in one of three ways: to t W , b Z , or b H . The search is carried out in final states with one, two, and more than two charged leptons, as well as in fully hadronic final states. Each of the channels in the exclusive final-state topologies is designed to be sensitive to specific combinations of the B quark-antiquark pair decays. The observed event yields are found to be consistent with the standard model expectations in all the final states studied. A statistical combination of these results is performed, and upper limits are set on the cross section of the strongly produced B quark-antiquark pairs as a function of the B quark mass. Lower limits on the B quark mass between 740 and 900 GeV are set at a 95% confidence level, depending on the values of the branching fractions of the B quark to t W , b Z , and b H . Overall, these limits are the most stringent to date.

  18. Derivatization of DNAs with Selenium at 6-Position of Guanine for Function and Crystal Structure Studies

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

    Salon, J.; Jiang, J; Sheng, J

    2008-01-01

    To investigate nucleic acid base pairing and stacking via atom-specific mutagenesis and crystallography, we have synthesized for the first time the 6-Se-deoxyguanosine phosphoramidite and incorporated it into DNAs via solid-phase synthesis with a coupling yield over 97%. We found that the UV absorption of the Se-DNAs red-shifts over 100 nm to 360 nm ({Epsilon} = 2.3 x 10{sup 4} M{sup -1} cm{sup -1}), the Se-DNAs are yellow colored, and this Se modification is relatively stable in water and at elevated temperature. Moreover, we successfully crystallized a ternary complex of the Se-G-DNA, RNA and RNase H. The crystal structure determination andmore » analysis reveal that the overall structures of the native and Se-modified nucleic acid duplexes are very similar, the selenium atom participates in a Se-mediated hydrogen bond (Se H-N), and the {sup Se}G and C form a base pair similar to the natural G-C pair though the Se-modification causes the base-pair to shift (approximately 0.3 {angstrom}). Our biophysical and structural studies provide new insights into the nucleic acid flexibility, duplex recognition and stability. Furthermore, this novel selenium modification of nucleic acids can be used to investigate chemogenetics and structure of nucleic acids and their protein complexes.« less

  19. Quadratic canonical transformation theory and higher order density matrices.

    PubMed

    Neuscamman, Eric; Yanai, Takeshi; Chan, Garnet Kin-Lic

    2009-03-28

    Canonical transformation (CT) theory provides a rigorously size-extensive description of dynamic correlation in multireference systems, with an accuracy superior to and cost scaling lower than complete active space second order perturbation theory. Here we expand our previous theory by investigating (i) a commutator approximation that is applied at quadratic, as opposed to linear, order in the effective Hamiltonian, and (ii) incorporation of the three-body reduced density matrix in the operator and density matrix decompositions. The quadratic commutator approximation improves CT's accuracy when used with a single-determinant reference, repairing the previous formal disadvantage of the single-reference linear CT theory relative to singles and doubles coupled cluster theory. Calculations on the BH and HF binding curves confirm this improvement. In multireference systems, the three-body reduced density matrix increases the overall accuracy of the CT theory. Tests on the H(2)O and N(2) binding curves yield results highly competitive with expensive state-of-the-art multireference methods, such as the multireference Davidson-corrected configuration interaction (MRCI+Q), averaged coupled pair functional, and averaged quadratic coupled cluster theories.

  20. Effects of cooperation between translating ribosome and RNA polymerase on termination efficiency of the Rho-independent terminator

    PubMed Central

    Li, Rui; Zhang, Qing; Li, Junbai; Shi, Hualin

    2016-01-01

    An experimental system was designed to measure in vivo termination efficiency (TE) of the Rho-independent terminator and position–function relations were quantified for the terminator tR2 in Escherichia coli. The terminator function was almost completely repressed when tR2 was located several base pairs downstream from the gene, and TE gradually increased to maximum values with the increasing distance between the gene and terminator. This TE–distance relation reflected a stochastic coupling of the ribosome and RNA polymerase (RNAP). Terminators located in the first 100 bp of the coding region can function efficiently. However, functional repression was observed when the terminator was located in the latter part of the coding region, and the degree of repression was determined by transcriptional and translational dynamics. These results may help to elucidate mechanisms of Rho-independent termination and reveal genomic locations of terminators and functions of the sequence that precedes terminators. These observations may have important applications in synthetic biology. PMID:26602687

  1. Postadsorption Work Function Tuning via Hydrogen Pressure Control

    PubMed Central

    2015-01-01

    The work function of metal substrates can be easily tuned, for instance, by adsorbing layers of molecular electron donors and acceptors. In this work, we discuss the possibility of changing the donor/acceptor mixing ratio reversibly after adsorption by choosing a donor/acceptor pair that is coupled via a redox reaction and that is in equilibrium with a surrounding gas phase. We discuss such a situation for the example of tetrafluoro-1,4-benzenediol (TFBD)/tetrafluoro-1,4-benzoquinone (TFBQ), adsorbed on Cu(111) and Ag(111) surfaces. We use density functional theory and ab initio thermodynamics to show that arbitrary TFBD/TFBQ mixing ratios can be set using hydrogen pressures attainable in low to ultrahigh vacuum. Adjusting the mixing ratio allows modifying the work function over a range of about 1 eV. Finally, we contrast single-species submonolayers with mixed layers to discuss why the resulting inhomogeneities in the electrostatic energy above the surface have different impacts on the interfacial level alignment and the work function. PMID:26692915

  2. Modeling DNA bubble formation at the atomic scale

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

    Beleva, V; Rasmussen, K. O.; Garcia, A. E.

    We describe the fluctuations of double stranded DNA molecules using a minimalist Go model over a wide range of temperatures. Minimalist models allow us to describe, at the atomic level, the opening and formation of bubbles in DNA double helices. This model includes all the geometrical constraints in helix melting imposed by the 3D structure of the molecule. The DNA forms melted bubbles within double helices. These bubbles form and break as a function of time. The equilibrium average number of broken base pairs shows a sharp change as a function of T. We observe a temperature profile of sequencemore » dependent bubble formation similar to those measured by Zeng et al. Long nuclei acid molecules melt partially through the formations of bubbles. It is known that CG rich sequences melt at higher temperatures than AT rich sequences. The melting temperature, however, is not solely determined by the CG content, but by the sequence through base stacking and solvent interactions. Recently, models that incorporate the sequence and nonlinear dynamics of DNA double strands have shown that DNA exhibits a very rich dynamics. Recent extensions of the Bishop-Peyrard model show that fluctuations in the DNA structure lead to opening in localized regions, and that these regions in the DNA are associated with transcription initiation sites. 1D and 2D models of DNA may contain enough information about stacking and base pairing interactions, but lack the coupling between twisting, bending and base pair opening imposed by the double helical structure of DNA that all atom models easily describe. However, the complexity of the energy function used in all atom simulations (including solvent, ions, etc) does not allow for the description of DNA folding/unfolding events that occur in the microsecond time scale.« less

  3. An efficient and near linear scaling pair natural orbital based local coupled cluster method.

    PubMed

    Riplinger, Christoph; Neese, Frank

    2013-01-21

    In previous publications, it was shown that an efficient local coupled cluster method with single- and double excitations can be based on the concept of pair natural orbitals (PNOs) [F. Neese, A. Hansen, and D. G. Liakos, J. Chem. Phys. 131, 064103 (2009)]. The resulting local pair natural orbital-coupled-cluster single double (LPNO-CCSD) method has since been proven to be highly reliable and efficient. For large molecules, the number of amplitudes to be determined is reduced by a factor of 10(5)-10(6) relative to a canonical CCSD calculation on the same system with the same basis set. In the original method, the PNOs were expanded in the set of canonical virtual orbitals and single excitations were not truncated. This led to a number of fifth order scaling steps that eventually rendered the method computationally expensive for large molecules (e.g., >100 atoms). In the present work, these limitations are overcome by a complete redesign of the LPNO-CCSD method. The new method is based on the combination of the concepts of PNOs and projected atomic orbitals (PAOs). Thus, each PNO is expanded in a set of PAOs that in turn belong to a given electron pair specific domain. In this way, it is possible to fully exploit locality while maintaining the extremely high compactness of the original LPNO-CCSD wavefunction. No terms are dropped from the CCSD equations and domains are chosen conservatively. The correlation energy loss due to the domains remains below <0.05%, which implies typically 15-20 but occasionally up to 30 atoms per domain on average. The new method has been given the acronym DLPNO-CCSD ("domain based LPNO-CCSD"). The method is nearly linear scaling with respect to system size. The original LPNO-CCSD method had three adjustable truncation thresholds that were chosen conservatively and do not need to be changed for actual applications. In the present treatment, no additional truncation parameters have been introduced. Any additional truncation is performed on the basis of the three original thresholds. There are no real-space cutoffs. Single excitations are truncated using singles-specific natural orbitals. Pairs are prescreened according to a multipole expansion of a pair correlation energy estimate based on local orbital specific virtual orbitals (LOSVs). Like its LPNO-CCSD predecessor, the method is completely of black box character and does not require any user adjustments. It is shown here that DLPNO-CCSD is as accurate as LPNO-CCSD while leading to computational savings exceeding one order of magnitude for larger systems. The largest calculations reported here featured >8800 basis functions and >450 atoms. In all larger test calculations done so far, the LPNO-CCSD step took less time than the preceding Hartree-Fock calculation, provided no approximations have been introduced in the latter. Thus, based on the present development reliable CCSD calculations on large molecules with unprecedented efficiency and accuracy are realized.

  4. Effect of electronic coupling of Watson-Crick hopping in DNA poly(dA)-poly(dT)

    NASA Astrophysics Data System (ADS)

    Risqi, A. M.; Yudiarsah, E.

    2017-07-01

    Charge transport properties of poly(dA)-poly(dT) DNA has been studied by using thigh binding Hamiltonian approach. Molecule DNA that we use consist of 32 base pair of adenine (A) and thymine (T) and backbone is consist of phosphate and sugar. The molecule DNA is contacted electrode at both ends. Charge transport in molecule DNA depend on the environment, we studied the effect of electronic coupling of Watson-Crick hopping in poly(dA)-poly(dT) DNA to transmission probability and characteristic I-V. The electronic coupling constant influence charge transport between adenine-thymine base pairs at the same site. Transmission probability is studied by using transfer matrix and scattering matrix method, and the result of transmission probability is used to calculate the characteristic I-V by using formula Landauer Buttiker. The result shows that when the electronic coupling increase then transmission probability and characteristic I-V increase slightly.

  5. Design of Current Leads for the MICE Coupling Magnet

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

    Wang, Li; Li, L.K.; Wu, Hong

    2008-04-02

    A pair of superconducting coupling magnets will be part of the Muon Ionization Cooling Experiment (MICE). They were designed and will be constructed by the Institute of Cryogenics and Superconductivity Technology, Harbin Institute of Technology, in collaboration with Lawrence Berkeley National Laboratory. The coupling magnet is to be cooled by using cryocoolers at 4.2K. In order to reduce the heat leak to the 4.2K cold mass from 300 K, a pair of current leads composed of conventional copper leads and high temperature superconductor (HTS) leads will be used to supply current to the magnet. This paper presents the optimization ofmore » the conventional conduction-cooled metal leads for the coupling magnet. Analyses on heat transfer down the leads using theoretical method and numerical simulation were carried out. The stray magnetic field around the HTS leads has been calculated and effects of the magnetic field on the performance of the HTS leads has also been analyzed.« less

  6. Scalable quantum computer architecture with coupled donor-quantum dot qubits

    DOEpatents

    Schenkel, Thomas; Lo, Cheuk Chi; Weis, Christoph; Lyon, Stephen; Tyryshkin, Alexei; Bokor, Jeffrey

    2014-08-26

    A quantum bit computing architecture includes a plurality of single spin memory donor atoms embedded in a semiconductor layer, a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, wherein a first voltage applied across at least one pair of the aligned quantum dot and donor atom controls a donor-quantum dot coupling. A method of performing quantum computing in a scalable architecture quantum computing apparatus includes arranging a pattern of single spin memory donor atoms in a semiconductor layer, forming a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, applying a first voltage across at least one aligned pair of a quantum dot and donor atom to control a donor-quantum dot coupling, and applying a second voltage between one or more quantum dots to control a Heisenberg exchange J coupling between quantum dots and to cause transport of a single spin polarized electron between quantum dots.

  7. The Role of Cytosine Methylation on Charge Transport through a DNA Strand

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

    Qi, Jianqing; Govind, Niranjan; Anantram, M. P.

    Cytosine methylation has been found to play a crucial role in various biological processes, including a number of human diseases. The detection of this small modifi-cation remains challenging. In this work, we computationally explore the possibility of detecting methylated DNA strands through direct electrical conductance measurements. Using density functional theory and the Landauer-Buttiker method, we study the electronic properties and charge transport through an eight base-pair methylated DNA strand and its native counterpart. Specifically, we compare the results generated with the widely used B3LYP exchange-correlation (XC) functional and CAM-B3LYP based tuned range-separated hybrid density functional. We first analyze the effectmore » of cytosine methylation on the tight-binding parameters of two DNA strands and then model the transmission of the electrons and conductance through the strands both with and without decoherence. We find that with both functionals, the main difference of the tight-binding parameters between the native DNA and the methylated DNA lies in the on-site energies of (methylated) cytosine bases. The intra- and interstrand hopping integrals between two nearest neighboring guanine base and (methylated) cytosine base also change with the addition of the methyl groups. Our calculations show that in the phase-coherent limit, the transmission of the methylated strand is close to the native strand when the energy is nearby the highest occupied molecular orbital (HOMO) level and larger than the native strand by 5 times in the bandgap. The trend in transmission also holds in the presence of the decoherence with both functionals. We also study the effect of contact coupling by choosing coupling strengths ranging from weak to strong coupling limit. Our results suggest that the effect of the two different functionals is to alter the on-site energies of the DNA bases at the HOMO level, while the transport properties don't depend much on the two functionals.« less

  8. Theoretical study of homonuclear J coupling between quadrupolar spins: single-crystal, DOR, and J-resolved NMR.

    PubMed

    Perras, Frédéric A; Bryce, David L

    2014-05-01

    The theory describing homonuclear indirect nuclear spin-spin coupling (J) interactions between pairs of quadrupolar nuclei is outlined and supported by numerical calculations. The expected first-order multiplets for pairs of magnetically equivalent (A2), chemically equivalent (AA'), and non-equivalent (AX) quadrupolar nuclei are given. The various spectral changeovers from one first-order multiplet to another are investigated with numerical simulations using the SIMPSON program and the various thresholds defining each situation are given. The effects of chemical equivalence, as well as quadrupolar coupling, chemical shift differences, and dipolar coupling on double-rotation (DOR) and J-resolved NMR experiments for measuring homonuclear J coupling constants are investigated. The simulated J coupling multiplets under DOR conditions largely resemble the ideal multiplets predicted for single crystals, and a characteristic multiplet is expected for each of the A2, AA', and AX cases. The simulations demonstrate that it should be straightforward to distinguish between magnetic inequivalence and equivalence using J-resolved NMR, as was speculated previously. Additionally, it is shown that the second-order quadrupolar-dipolar cross-term does not affect the splittings in J-resolved experiments. Overall, the homonuclear J-resolved experiment for half-integer quadrupolar nuclei is demonstrated to be robust with respect to the effects of first- and second-order quadrupolar coupling, dipolar coupling, and chemical shift differences. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Bright-dark soliton pairs in a self-mode locking fiber laser

    NASA Astrophysics Data System (ADS)

    Meng, Yichang; Zhang, Shumin; Li, Hongfei; Du, Juan; Hao, Yanping; Li, Xingliang

    2012-06-01

    We have experimentally observed bright-dark soliton pairs in an erbium-doped fiber ring laser for the first time. This approach is different from the vector dark domain wall solitons which separate the two orthogonal linear polarization eigenstates of the laser emission. In our laser, the bright-dark soliton pairs can co-exist in any one polarization state. Numerical simulations based on the coupled complex Ginzburg-Landau equations have confirmed the experimental results.

  10. Mechanical design of deformation compensated flexural pivots structured for linear nanopositioning stages

    DOEpatents

    Shu, Deming; Kearney, Steven P.; Preissner, Curt A.

    2015-02-17

    A method and deformation compensated flexural pivots structured for precision linear nanopositioning stages are provided. A deformation-compensated flexural linear guiding mechanism includes a basic parallel mechanism including a U-shaped member and a pair of parallel bars linked to respective pairs of I-link bars and each of the I-bars coupled by a respective pair of flexural pivots. The basic parallel mechanism includes substantially evenly distributed flexural pivots minimizing center shift dynamic errors.

  11. N-H Stretching Excitations in Adenosine-Thymidine Base Pairs in Solution: Base Pair Geometries, Infrared Line Shapes and Ultrafast Vibrational Dynamics

    PubMed Central

    Greve, Christian; Preketes, Nicholas K.; Fidder, Henk; Costard, Rene; Koeppe, Benjamin; Heisler, Ismael A.; Mukamel, Shaul; Temps, Friedrich; Nibbering, Erik T. J.; Elsaesser, Thomas

    2013-01-01

    We explore the N-H stretching vibrations of adenosine-thymidine base pairs in chloroform solution with linear and nonlinear infrared spectroscopy. Based on estimates from NMR measurements and ab initio calculations, we conclude that adenosine and thymidine form hydrogen bonded base pairs in Watson-Crick, reverse Watson-Crick, Hoogsteen and reverse Hoogsteen configurations with similar probability. Steady-state concentration- and temperature dependent linear FT-IR studies, including H/D exchange experiments, reveal that these hydrogen-bonded base pairs have complex N-H/N-D stretching spectra with a multitude of spectral components. Nonlinear 2D-IR spectroscopic results, together with IR-pump-IR-probe measurements, as also corroborated by ab initio calculations, reveal that the number of N-H stretching transitions is larger than the total number of N-H stretching modes. This is explained by couplings to other modes, such as an underdamped low-frequency hydrogen-bond mode, and a Fermi resonance with NH2 bending overtone levels of the adenosine amino-group. Our results demonstrate that modeling based on local N-H stretching vibrations only is not sufficient and call for further refinement of the description of the N-H stretching manifolds of nucleic acid base pairs of adenosine and thymidine, incorporating a multitude of couplings with fingerprint and low-frequency modes. PMID:23234439

  12. Pinning down electroweak dipole operators of the top quark

    DOE PAGES

    Schulze, Markus; Soreq, Yotam

    2016-08-19

    Here, we consider hadronic top quark pair production and pair production in association with a photon or a Z boson to probe electroweak dipole couplings in tb¯W, tt¯γ, and tt¯Z interactions. We demonstrate how measurements of these processes at the 13 TeV LHC can be combined to disentangle and constrain anomalous dipole operators. The construction of cross section ratios allows us to significantly reduce various uncertainties and exploit orthogonal sensitivity between the tt¯γ and tt¯Z couplings. In addition, we show that angular correlations in tt¯ production can be used to constrain the remaining tb¯W dipole operator. Our approach yields excellentmore » sensitivity to the anomalous couplings and can be a further step toward precise and direct measurements of the top quark electroweak interactions.« less

  13. Supercurrent as a probe for topological superconductivity in magnetic adatom chains

    NASA Astrophysics Data System (ADS)

    Mohanta, Narayan; Kampf, Arno P.; Kopp, Thilo

    2018-06-01

    A magnetic adatom chain, proximity coupled to a conventional superconductor with spin-orbit coupling, exhibits locally an odd-parity, spin-triplet pairing amplitude. We show that the singlet-triplet junction, thus formed, leads to a net spin accumulation in the near vicinity of the chain. The accumulated spins are polarized along the direction of the local d vector for triplet pairing and generate an enhanced persistent current flowing around the chain. The spin polarization and the "supercurrent" reverse their directions beyond a critical exchange coupling strength at which the singlet superconducting order changes its sign on the chain. The current is strongly enhanced in the topological superconducting regime where Majorana bound states appear at the chain ends. The current and the spin profile offer alternative routes to characterize the topological superconducting state in adatom chains and islands.

  14. Localization and oscillations of Majorana fermions in a two-dimensional electron gas coupled with d -wave superconductors

    NASA Astrophysics Data System (ADS)

    Ortiz, L.; Varona, S.; Viyuela, O.; Martin-Delgado, M. A.

    2018-02-01

    We study the localization and oscillation properties of the Majorana fermions that arise in a two-dimensional electron gas (2DEG) with spin-orbit coupling (SOC) and a Zeeman field coupled with a d -wave superconductor. Despite the angular dependence of the d -wave pairing, localization and oscillation properties are found to be similar to the ones seen in conventional s -wave superconductors. In addition, we study a microscopic lattice version of the previous system that can be characterized by a topological invariant. We derive its real space representation that involves nearest and next-to-nearest-neighbors pairing. Finally, we show that the emerging chiral Majorana fermions are indeed robust against static disorder. This analysis has potential applications to quantum simulations and experiments in high-Tc superconductors.

  15. Benchmark of Dynamic Electron Correlation Models for Seniority-Zero Wave Functions and Their Application to Thermochemistry.

    PubMed

    Boguslawski, Katharina; Tecmer, Paweł

    2017-12-12

    Wave functions restricted to electron-pair states are promising models to describe static/nondynamic electron correlation effects encountered, for instance, in bond-dissociation processes and transition-metal and actinide chemistry. To reach spectroscopic accuracy, however, the missing dynamic electron correlation effects that cannot be described by electron-pair states need to be included a posteriori. In this Article, we extend the previously presented perturbation theory models with an Antisymmetric Product of 1-reference orbital Geminal (AP1roG) reference function that allows us to describe both static/nondynamic and dynamic electron correlation effects. Specifically, our perturbation theory models combine a diagonal and off-diagonal zero-order Hamiltonian, a single-reference and multireference dual state, and different excitation operators used to construct the projection manifold. We benchmark all proposed models as well as an a posteriori Linearized Coupled Cluster correction on top of AP1roG against CR-CC(2,3) reference data for reaction energies of several closed-shell molecules that are extrapolated to the basis set limit. Moreover, we test the performance of our new methods for multiple bond breaking processes in the homonuclear N 2 , C 2 , and F 2 dimers as well as the heteronuclear BN, CO, and CN + dimers against MRCI-SD, MRCI-SD+Q, and CR-CC(2,3) reference data. Our numerical results indicate that the best performance is obtained from a Linearized Coupled Cluster correction as well as second-order perturbation theory corrections employing a diagonal and off-diagonal zero-order Hamiltonian and a single-determinant dual state. These dynamic corrections on top of AP1roG provide substantial improvements for binding energies and spectroscopic properties obtained with the AP1roG approach, while allowing us to approach chemical accuracy for reaction energies involving closed-shell species.

  16. Charge transfer polarisation wave in high Tc oxides and superconductive pairing

    NASA Technical Reports Server (NTRS)

    Chakraverty, B. K.

    1991-01-01

    A general formalism of quantized charge transfer polarization waves was developed. The nature of possible superconductive pairing between oxygen holes is discussed. Unlike optical phonons, these polarization fields will give rise to dielectric bipolarons or bipolaron bubbles. In the weak coupling limit, a new class of superconductivity is to be expected.

  17. Magnetoelectric Andreev Effect due to Proximity-Induced Nonunitary Triplet Superconductivity in Helical Metals

    NASA Astrophysics Data System (ADS)

    Tkachov, G.

    2017-01-01

    Noncentrosymmetric superconductors exhibit the magnetoelectric effect, which manifests itself in the appearance of the magnetic spin polarization in response to a dissipationless electric current (supercurrent). While much attention has been dedicated to the thermodynamic version of this phenomenon (Edelstein effect), nonequilibrium transport magnetoelectric effects have not been explored yet. We propose the magnetoelectric Andreev effect (MAE), which consists in the generation of spin-polarized triplet Andreev conductance by an electric supercurrent. The MAE stems from the spin polarization of the Cooper-pair condensate due to a supercurrent-induced nonunitary triplet pairing. We propose the realization of such a nonunitary pairing and MAE in superconducting proximity structures based on two-dimensional helical metals—strongly spin-orbit-coupled electronic systems with the Dirac spectrum such as the topological surface states. Our results uncover an unexplored route towards electrically controlled superconducting spintronics and are a smoking gun for induced unconventional superconductivity in spin-orbit-coupled materials.

  18. Strong-coupling effects in superfluid He3 in aerogel

    NASA Astrophysics Data System (ADS)

    Aoyama, Kazushi; Ikeda, Ryusuke

    2007-09-01

    Effects of impurity scatterings on the strong-coupling (SC) contribution, stabilizing the ABM (axial) pairing state, to the quartic term of the Ginzburg-Landau free energy of superfluid He3 are theoretically studied to examine recent observations suggestive of an anomalously small SC effect in superfluid He3 in aerogels. To study the SC corrections, two approaches are used. One is based on a perturbation in the short-range repulsive interaction, and the other is a phenomenological approach used previously for the bulk liquid by Sauls and Serene [Phys. Rev. B 24, 183 (1981)]. It is found that the impurity scattering favors the BW pairing state and shrinks the region of the ABM pairing state in the T-P phase diagram. In the phenomenological approach, the resulting shrinkage of the ABM region is especially substantial and, if assuming an anisotropy over a large scale in aerogel, leads to justifying the phase diagrams determined experimentally.

  19. Separation of the Stern and diffuse layer in coarse-grained models: the cases of phosphatidyl serine, phosphatidic acid, and PIP2 monolayers.

    PubMed

    Vangaveti, S; Travesset, A

    2014-12-28

    We present here a method to separate the Stern and diffuse layer in general systems into two regions that can be analyzed separately. The Stern layer can be described in terms of Bjerrum pairing and the diffuse layer in terms of Poisson-Boltzmann theory (monovalent) or strong coupling theory plus a slowly decaying tail (divalent). We consider three anionic phospholipids: phosphatidyl serine, phosphatidic acid, and phosphatidylinositol(4,5)bisphosphate (PIP2), which we describe within a minimal coarse-grained model as a function of ionic concentration. The case of mixed lipid systems is also considered, which shows a high level of binding cooperativity as a function of PIP2 localization. Implications for existing experimental systems of lipid heterogeneities are also discussed.

  20. Separation of the Stern and diffuse layer in coarse-grained models: The cases of phosphatidyl serine, phosphatidic acid, and PIP2 monolayers

    NASA Astrophysics Data System (ADS)

    Vangaveti, S.; Travesset, A.

    2014-12-01

    We present here a method to separate the Stern and diffuse layer in general systems into two regions that can be analyzed separately. The Stern layer can be described in terms of Bjerrum pairing and the diffuse layer in terms of Poisson-Boltzmann theory (monovalent) or strong coupling theory plus a slowly decaying tail (divalent). We consider three anionic phospholipids: phosphatidyl serine, phosphatidic acid, and phosphatidylinositol(4,5)bisphosphate (PIP2), which we describe within a minimal coarse-grained model as a function of ionic concentration. The case of mixed lipid systems is also considered, which shows a high level of binding cooperativity as a function of PIP2 localization. Implications for existing experimental systems of lipid heterogeneities are also discussed.

  1. Superconductivity in 2D and nearly 2D: A Conserving Description

    NASA Astrophysics Data System (ADS)

    Deisz, John; Hess, Daryl; Serene, Joe

    1998-03-01

    In a previous work,(J.J. Deisz, D.W. Hess, and J.W. Serene, Phys. Rev. Lett., to appear.) we used a 2D Hubbard model with an attractive interaction to explicitly show that a superconducting state in the fluctuation exchange approximation (FEA) could be detected from self-consistent calculations of the internal energy and free energy as a function of a threaded flux. The FEA is a conserving approximation beyond mean field theory that includes the exchange of Cooper pair, density, and spin fluctuations. Here, we present extensions of our previous calculations and show a phase diagram as a function of interaction strength and density. We discuss the nature of the FEA phase transition in 2D and focus on how it changes with increasing coupling between planes.

  2. Combinatorial semantics strengthens angular-anterior temporal coupling.

    PubMed

    Molinaro, Nicola; Paz-Alonso, Pedro M; Duñabeitia, Jon Andoni; Carreiras, Manuel

    2015-04-01

    The human semantic combinatorial system allows us to create a wide number of new meanings from a finite number of existing representations. The present study investigates the neural dynamics underlying the semantic processing of different conceptual constructions based on predictions from previous neuroanatomical models of the semantic processing network. In two experiments, participants read sentences for comprehension containing noun-adjective pairs in three different conditions: prototypical (Redundant), nonsense (Anomalous) and low-typical but composable (Contrastive). In Experiment 1 we examined the processing costs associated to reading these sentences and found a processing dissociation between Anomalous and Contrastive word pairs, compared to prototypical (Redundant) stimuli. In Experiment 2, functional connectivity results showed strong co-activation across conditions between inferior frontal gyrus (IFG) and posterior middle temporal gyrus (MTG), as well as between these two regions and middle frontal gyrus (MFG), anterior temporal cortex (ATC) and fusiform gyrus (FG), consistent with previous neuroanatomical models. Importantly, processing of low-typical (but composable) meanings relative to prototypical and anomalous constructions was associated with a stronger positive coupling between ATC and angular gyrus (AG). Our results underscore the critical role of IFG-MTG co-activation during semantic processing and how other relevant nodes within the semantic processing network come into play to handle visual-orthographic information, to maintain multiple lexical-semantic representations in working memory and to combine existing representations while creatively constructing meaning. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Complex Dynamics of Delay-Coupled Neural Networks

    NASA Astrophysics Data System (ADS)

    Mao, Xiaochen

    2016-09-01

    This paper reveals the complicated dynamics of a delay-coupled system that consists of a pair of sub-networks and multiple bidirectional couplings. Time delays are introduced into the internal connections and network-couplings, respectively. The stability and instability of the coupled network are discussed. The sufficient conditions for the existence of oscillations are given. Case studies of numerical simulations are given to validate the analytical results. Interesting and complicated neuronal activities are observed numerically, such as rest states, periodic oscillations, multiple switches of rest states and oscillations, and the coexistence of different types of oscillations.

  4. Commercial probiotic bacteria and prebiotic carbohydrates: a fundamental study on prebiotics uptake, antimicrobials production and inhibition of pathogens.

    PubMed

    Cruz-Guerrero, Alma; Hernández-Sánchez, Humberto; Rodríguez-Serrano, Gabriela; Gómez-Ruiz, Lorena; García-Garibay, Mariano; Figueroa-González, Ivonne

    2014-08-01

    Probiotics and prebiotics are among the most important functional food ingredients worldwide. The proven benefits of such ingredients to human health have encouraged the development of functional foods containing both probiotics and prebiotics. In this work, the production of antimicrobial compounds coupled to the uptake of commercial prebiotics by probiotic bacteria was investigated. The probiotic bacteria studied were able to take up commercial prebiotic carbohydrates to the same or higher extent than that observed for lactose (control carbohydrate). The growth of probiotic bacteria was coupled to the production of antimicrobials such as short-chain fatty acids (SCFA), H2 O2 and bacteriocins. A higher production of antimicrobial compounds was recorded with Oligomate 55® compared with Regulact® and Frutafit® (3-5 and 10-115 times higher SCFA and H2 O2 production, respectively). The probiotic bacteria grown with Oligomate 55® also produced bacteriocins and other non-identified antimicrobial compounds. The antimicrobials produced by the probiotic bacteria inhibited up to 50% the growth of model pathogens such as Escherichia coli, Listeria innocua and Micrococcus luteus compared with control cultures. The results here obtained are useful for the adequate selection of probiotic/prebiotics pairs and therefore in the development of efficient functional foods. © 2013 Society of Chemical Industry.

  5. Animal-to-animal variability in the phasing of the crustacean cardiac motor pattern: an experimental and computational analysis

    PubMed Central

    Williams, Alex H.; Kwiatkowski, Molly A.; Mortimer, Adam L.; Marder, Eve; Zeeman, Mary Lou

    2013-01-01

    The cardiac ganglion (CG) of Homarus americanus is a central pattern generator that consists of two oscillatory groups of neurons: “small cells” (SCs) and “large cells” (LCs). We have shown that SCs and LCs begin their bursts nearly simultaneously but end their bursts at variable phases. This variability contrasts with many other central pattern generator systems in which phase is well maintained. To determine both the consequences of this variability and how CG phasing is controlled, we modeled the CG as a pair of Morris-Lecar oscillators coupled by electrical and excitatory synapses and constructed a database of 15,000 simulated networks using random parameter sets. These simulations, like our experimental results, displayed variable phase relationships, with the bursts beginning together but ending at variable phases. The model suggests that the variable phasing of the pattern has important implications for the functional role of the excitatory synapses. In networks in which the two oscillators had similar duty cycles, the excitatory coupling functioned to increase cycle frequency. In networks with disparate duty cycles, it functioned to decrease network frequency. Overall, we suggest that the phasing of the CG may vary without compromising appropriate motor output and that this variability may critically determine how the network behaves in response to manipulations. PMID:23446690

  6. Theoretical Studies of Microstrip Antennas : Volume I, General Design Techniques and Analyses of Single and Coupled Elements

    DOT National Transportation Integrated Search

    1979-09-01

    Volume 1 of Theoretical Studies of Microstrip Antennas deals with general techniques and analyses of single and coupled radiating elements. Specifically, we review and then employ an important equivalence theorem that allows a pair of vector potentia...

  7. Fully differential Higgs boson pair production in association with a Z boson at next-to-next-to-leading order in QCD

    NASA Astrophysics Data System (ADS)

    Li, Hai Tao; Li, Chong Sheng; Wang, Jian

    2018-04-01

    We present a fully differential next-to-next-to-leading order QCD calculation of the Higgs pair production in association with a Z boson at hadron colliders, which is important for probing the trilinear Higgs self-coupling. The next-to-next-to-leading-order corrections enhance the next-to-leading order total cross sections by a factor of 1.2-1.5, depending on the collider energy, and change the shape of next-to-leading order kinematic distributions. We discuss how to determine the trilinear Higgs self-coupling using our results.

  8. Fully differential Higgs boson pair production in association with a Z boson at next-to-next-to-leading order in QCD

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

    Li, Hai Tao; Li, Chong Sheng; Wang, Jian

    Here, we present a fully differential next-to-next-to-leading order QCD calculation of the Higgs pair production in association with a Z boson at hadron colliders, which is important for probing the trilinear Higgs self-coupling. The next-to-next-to-leading-order corrections enhance the next-to-leading order total cross sections by a factor of 1.2–1.5, depending on the collider energy, and change the shape of next-to-leading order kinematic distributions. We discuss how to determine the trilinear Higgs self-coupling using our results.

  9. System for automatically switching transformer coupled lines

    NASA Technical Reports Server (NTRS)

    Dwinell, W. S. (Inventor)

    1979-01-01

    A system is presented for automatically controlling transformer coupled alternating current electric lines. The secondary winding of each transformer is provided with a center tap. A switching circuit is connected to the center taps of a pair of secondary windings and includes a switch controller. An impedance is connected between the center taps of the opposite pair of secondary windings. The switching circuit has continuity when the AC lines are continuous and discontinuity with any disconnect of the AC lines. Normally open switching means are provided in at least one AC line. The switch controller automatically opens the switching means when the AC lines become separated.

  10. NLO QCD effective field theory analysis of W+W- production at the LHC including fermionic operators

    NASA Astrophysics Data System (ADS)

    Baglio, Julien; Dawson, Sally; Lewis, Ian M.

    2017-10-01

    We study the impact of anomalous gauge boson and fermion couplings on the production of W+W- pairs at the LHC. Helicity amplitudes are presented separately to demonstrate the sources of new physics contributions and the impact of QCD and electroweak corrections. The QCD corrections have important effects on the fits to anomalous couplings, in particular when one W boson is longitudinally polarized and the other is transversely polarized. In effective field theory language, we demonstrate that the dimension-6 approximation to constraining new physics effects in W+W- pair production fails at pT˜500 - 1000 GeV .

  11. Fully differential Higgs boson pair production in association with a Z boson at next-to-next-to-leading order in QCD

    DOE PAGES

    Li, Hai Tao; Li, Chong Sheng; Wang, Jian

    2018-04-23

    Here, we present a fully differential next-to-next-to-leading order QCD calculation of the Higgs pair production in association with a Z boson at hadron colliders, which is important for probing the trilinear Higgs self-coupling. The next-to-next-to-leading-order corrections enhance the next-to-leading order total cross sections by a factor of 1.2–1.5, depending on the collider energy, and change the shape of next-to-leading order kinematic distributions. We discuss how to determine the trilinear Higgs self-coupling using our results.

  12. Effect of electrode impedance on spread of excitation and pitch perception using electrically coupled “dual-electrode” stimulation

    PubMed Central

    Hughes, Michelle L.; Baudhuin, Jacquelyn L.; Goehring, Jenny L.

    2014-01-01

    Objective In newer-generation Cochlear Ltd. cochlear implants, two adjacent electrodes can be electrically coupled to produce a single contact or “dual electrode” (DE). The goal of the present study was to evaluate whether relatively large impedance differences (>3.0 kOhms) between coupled electrodes affect the excitation pattern and pitch percepts produced by the DE. Design Fifteen electrode pairs in six recipients were tested. Neural spread-of-excitation (SOE) patterns and pitch perception were measured for adjacent physical electrodes (PEs) and the resulting DE to determine if the lower-impedance PE in the pair dominates the DE response pattern. Results were compared to a “normative sample” (impedance differences <3.0 kOhms) from two earlier studies. Results In general, SOE patterns for DEs more closely approximated those of the lower-impedance PE in each pair. The DE was more easily distinguished in pitch from the higher-impedance PE than the lower-impedance PE. The ECAP and perceptual results generally differed from those of the normative group. Conclusions Impedance differences between adjacent PEs should be considered if DE stimulation is implemented in future research studies or clinical coding strategies. PMID:25250960

  13. Corrections to di-Higgs boson production with light stops and modified Higgs couplings

    NASA Astrophysics Data System (ADS)

    Huang, Peisi; Joglekar, Aniket; Li, Min; Wagner, Carlos E. M.

    2018-04-01

    The Higgs pair production in gluon fusion is a sensitive probe of beyond-standard model (BSM) phenomena and its detection is a major goal for the LHC and higher energy hadron collider experiments. In this work we reanalyze the possible modifications of the Higgs pair production cross section within low energy supersymmetry models. We show that the supersymmetric contributions to the Higgs pair production cross section are strongly correlated with the ones of the single Higgs production in the gluon fusion channel. Motivated by the analysis of ATLAS and CMS Higgs production data, we show that the scalar superpartners' contributions may lead to significant modification of the di-Higgs production rate and invariant mass distribution with respect to the SM predictions. We also analyze the combined effects on the di-Higgs production rate of a modification of the Higgs trilinear and top-quark Yukawa couplings in the presence of light stops. In particular, we show that due to the destructive interference of the triangle and box amplitude contributions to the di-Higgs production cross section, even a small modification of the top-quark Yukawa coupling can lead to a significant increase of the di-Higgs production rate.

  14. Transport properties of layered Ba(Pb,Bi)O3 thin films

    NASA Astrophysics Data System (ADS)

    Hassink, G. W. J.; Munakata, K.; Hammond, R. H.; Beasley, M. R.

    2012-02-01

    Doped BaBiO3 is a 3D oxide superconductor with a maximum Tc of 30 K for Ba0.6K0.4BiO3. There has been a lot of discussion on whether this high Tc can be explained purely by electron-phonon coupling with a high coupling constant λ. In addition, the presence of real-space paired 6s^2 electrons in the parent compound raise intriguing questions about whether there is an electron-electron coupling interaction as well. This possible negative-U interaction might be used to implement the suggestion by Berg, Orgad and Kivelson [Phys.Rev.B 78, 094509] that for a two-layer system where one layer provides electron pairing interaction and the other layer is conducting, the whole can be superconducting with a high Tc. Here we discuss the transport properties of BaPbO3/BaBiO3 bilayers, where the BaBiO3 layer is thought to act as the pairing layer, while the BaPbO3 acts as the conducting layer. The transport behavior changes to insulating upon decreasing the metallic BaPbO3 layer thickness at values that single films are expected to still be metallic.

  15. Torsion-rotation structure and quasi-symmetric-rotor behaviour for the CH3SH asymmetric CH3-bending and C-H stretching bands of E parentage

    NASA Astrophysics Data System (ADS)

    Lees, R. M.; Xu, Li-Hong; Guislain, B. G.; Reid, E. M.; Twagirayezu, S.; Perry, D. S.; Dawadi, M. B.; Thapaliya, B. P.; Billinghurst, B. E.

    2018-01-01

    High-resolution Fourier transform spectra of the asymmetric methyl-bending and methyl-stretching bands of CH3SH have been recorded employing synchrotron radiation at the FIR beamline of the Canadian Light Source. Analysis of the torsion-rotation structure and relative intensities has revealed the novel feature that for both bend and stretch the in-plane and out-of-plane modes behave much like a Coriolis-coupled l-doublet pair originating from degenerate E modes of a symmetric top. As the axial angular momentum K increases, the energies of the coupled "l = ±1" modes diverge linearly, with effective Coriolis ζ constants typical for symmetric tops. For the methyl-stretching states, separated at K = 0 by only about 1 cm-1, the assigned sub-bands follow a symmetric top Δ(K - l) = 0 selection rule, with only ΔK = -1 transitions observed to the upper l = -1 in-plane A‧ component and only ΔK = +1 transitions to the lower l = +1 out-of-plane A″ component. The K = 0 separation of the CH3-bending states is larger at 9.1 cm-1 with the l-ordering reversed. Here, both ΔK = +1 and ΔK = -1 transitions are seen for each l-component but with a large difference in relative intensity. Term values for the excited state levels have been fitted to J(J + 1) power-series expansions to obtain substate origins. These have then been fitted to a Fourier model to characterize the torsion-K-rotation energy patterns. For both pairs of vibrational states, the torsional energies display the customary oscillatory behaviour as a function of K and have inverted torsional splittings relative to the ground state. The spectra show numerous perturbations, indicating local resonances with the underlying bath of high torsional levels and vibrational combination and overtone states. The overall structure of the two pairs of bands represents a new regime in which the vibrational energy separations, torsional splittings and shifts due to molecular asymmetry are all of the same order, creating a challenging and complex vibration-torsion-rotation coupling environment.

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

    Reppert, Mike; Kell, Adam; Pruitt, Thomas

    The vibrational spectral density is an important physical parameter needed to describe both linear and non-linear spectra of multi-chromophore systems such as photosynthetic complexes. Low-temperature techniques such as hole burning (HB) and fluorescence line narrowing are commonly used to extract the spectral density for a given electronic transition from experimental data. We report here that the lineshape function formula reported by Hayes et al. [J. Phys. Chem. 98, 7337 (1994)] in the mean-phonon approximation and frequently applied to analyzing HB data contains inconsistencies in notation, leading to essentially incorrect expressions in cases of moderate and strong electron-phonon (el-ph) coupling strengths.more » A corrected lineshape function L(ω) is given that retains the computational and intuitive advantages of the expression of Hayes et al. [J. Phys. Chem. 98, 7337 (1994)]. Although the corrected lineshape function could be used in modeling studies of various optical spectra, we suggest that it is better to calculate the lineshape function numerically, without introducing the mean-phonon approximation. New theoretical fits of the P870 and P960 absorption bands and frequency-dependent resonant HB spectra of Rb. sphaeroides and Rps. viridis reaction centers are provided as examples to demonstrate the importance of correct lineshape expressions. Comparison with the previously determined el-ph coupling parameters [Johnson et al., J. Phys. Chem. 94, 5849 (1990); Lyle et al., ibid. 97, 6924 (1993); Reddy et al., ibid. 97, 6934 (1993)] is also provided. The new fits lead to modified el-ph coupling strengths and different frequencies of the special pair marker mode, ω{sub sp}, for Rb. sphaeroides that could be used in the future for more advanced calculations of absorption and HB spectra obtained for various bacterial reaction centers.« less

  17. Connexin36 vs. connexin32, "miniature" neuronal gap junctions, and limited electrotonic coupling in rodent suprachiasmatic nucleus.

    PubMed

    Rash, J E; Olson, C O; Pouliot, W A; Davidson, K G V; Yasumura, T; Furman, C S; Royer, S; Kamasawa, N; Nagy, J I; Dudek, F E

    2007-10-26

    Suprachiasmatic nucleus (SCN) neurons generate circadian rhythms, and these neurons normally exhibit loosely-synchronized action potentials. Although electrotonic coupling has long been proposed to mediate this neuronal synchrony, ultrastructural studies have failed to detect gap junctions between SCN neurons. Nevertheless, it has been proposed that neuronal gap junctions exist in the SCN; that they consist of connexin32 or, alternatively, connexin36; and that connexin36 knockout eliminates neuronal coupling between SCN neurons and disrupts circadian rhythms. We used confocal immunofluorescence microscopy and freeze-fracture replica immunogold labeling to examine the distributions of connexin30, connexin32, connexin36, and connexin43 in rat and mouse SCN and used whole-cell recordings to re-assess electrotonic and tracer coupling. Connexin32-immunofluorescent puncta were essentially absent in SCN but connexin36 was relatively abundant. Fifteen neuronal gap junctions were identified ultrastructurally, all of which contained connexin36 but not connexin32, whereas nearby oligodendrocyte gap junctions contained connexin32. In adult SCN, one neuronal gap junction was >600 connexons, whereas 75% were smaller than 50 connexons, which may be below the limit of detectability by fluorescence microscopy and thin-section electron microscopy. Whole-cell recordings in hypothalamic slices revealed tracer coupling with neurobiotin in <5% of SCN neurons, and paired recordings (>40 pairs) did not reveal obvious electrotonic coupling or synchronized action potentials, consistent with few neurons possessing large gap junctions. However, most neurons had partial spikes or spikelets (often <1 mV), which remained after QX-314 [N-(2,6-dimethylphenylcarbamoylmethyl)triethylammonium bromide] had blocked sodium-mediated action potentials within the recorded neuron, consistent with spikelet transmission via small gap junctions. Thus, a few "miniature" gap junctions on most SCN neurons appear to mediate weak electrotonic coupling between limited numbers of neuron pairs, thus accounting for frequent detection of partial spikes and hypothetically providing the basis for "loose" electrical or metabolic synchronization of electrical activity commonly observed in SCN neuronal populations during circadian rhythms.

  18. A Prenatal Coparenting Intervention With Unmarried Father-Mother Dyads: Fidelity of Intervention Delivery by Male-Female Community Mentor Teams.

    PubMed

    Salman-Engin, Selin; Little, Tara; Gaskin-Butler, Vikki; McHale, James P

    2017-06-01

    Most prenatal preventive interventions for unmarried mothers do not integrate fathers or help the parents plan for the development of a functional coparenting alliance after the baby's arrival. Furthermore, properly trained professionals have only rarely examined the fidelity of these interventions. This report examines whether experienced community interventionists (home visitors, health educators, fatherhood service personnel) with no formal couples' therapy training are capable of pairing together to deliver with adequate fidelity a manualized dyadic intervention designed for expectant unmarried mothers and fathers. Three male and four female mentors (home visitors, health educators, fatherhood personnel) working in paired male-female co-mentor teams delivered a seven-session "Figuring It Out for the Child" curriculum (six prenatal sessions, one booster) to 14 multirisk, unmarried African American families (parent age ranging from 14 to 40). Parental well-being and views of fatherhood were assessed before the intervention and again 3 months after the baby's birth. Quality assurance analysts evaluated mentor fidelity (adherence to the curriculum, competence in engaging couples with specified curricular content) through a review of the transcripts and audiotapes from the sessions. Mentors also rated their own adherence. Although the mentors overestimated adherence, quality assurance analyst ratings found acceptable levels of adherence and competence, with no significant male-female differences in fidelity. Adherence and competence were marginally higher in sessions that required fewer direct couples' interventions. Parents reported satisfaction with the interventions and showed statistically significant improvement in the family dimensions of interest at 3-4 months posttreatment. Findings support the wisdom of engaging men both as interventionists and as recipients of prenatal coparenting interventions-even in families where the parents are uncoupled and non-co-residential.

  19. Single-round selection yields a unique retroviral envelope utilizing GPR172A as its host receptor.

    PubMed

    Mazari, Peter M; Linder-Basso, Daniela; Sarangi, Anindita; Chang, Yehchung; Roth, Monica J

    2009-04-07

    The recognition by a viral envelope of its cognate host-cell receptor is the initial critical step in defining the viral host-range and tissue specificity. This study combines a single-round of selection of a random envelope library with a parallel cDNA screen for receptor function to identify a distinct retroviral envelope/receptor pair. The 11-aa targeting domain of the modified feline leukemia virus envelope consists of a constrained peptide. Critical to the binding of the constrained peptide envelope to its cellular receptor are a pair of internal cysteines and an essential Trp required for maintenance of titers >10(5) lacZ staining units per milliliter. The receptor used for viral entry is the human GPR172A protein, a G-protein-coupled receptor isolated from osteosarcoma cells. The ability to generate unique envelopes capable of using tissue- or disease-specific receptors marks an advance in the development of efficient gene-therapy vectors.

  20. Symmetry protected topological Luttinger liquids and the phase transition between them

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

    None

    2018-01-01

    We show that a doped spin-1/2 ladder with antiferromagnetic intra-chain and ferromagnetic inter-chain coupling is a symmetry protected topologically non-trivial Luttinger liquid. Turning on a large easy-plane spin anisotropy drives the system to a topologically-trivial Luttinger liquid. Both phases have full spin gaps and exhibit power-law superconducting pair correlation. The Cooper pair symmetry is singletmore » $$d_{xy}$$ in the non-trivial phase and triplet $$S_z=0$$ in the trivial phase. The topologically non-trivial Luttinger liquid exhibits gapless spin excitations in the presence of a boundary, and it has no non-interacting or mean-field theory analog even when the fluctuating phase in the charge sector is pinned. As a function of the strength of spin anisotropy there is a topological phase transition upon which the spin gap closes. We speculate these Luttinger liquids are relevant to the superconductivity in metalized integer spin ladders or chains.« less

  1. Principal component analysis for fermionic critical points

    NASA Astrophysics Data System (ADS)

    Costa, Natanael C.; Hu, Wenjian; Bai, Z. J.; Scalettar, Richard T.; Singh, Rajiv R. P.

    2017-11-01

    We use determinant quantum Monte Carlo (DQMC), in combination with the principal component analysis (PCA) approach to unsupervised learning, to extract information about phase transitions in several of the most fundamental Hamiltonians describing strongly correlated materials. We first explore the zero-temperature antiferromagnet to singlet transition in the periodic Anderson model, the Mott insulating transition in the Hubbard model on a honeycomb lattice, and the magnetic transition in the 1/6-filled Lieb lattice. We then discuss the prospects for learning finite temperature superconducting transitions in the attractive Hubbard model, for which there is no sign problem. Finally, we investigate finite temperature charge density wave (CDW) transitions in the Holstein model, where the electrons are coupled to phonon degrees of freedom, and carry out a finite size scaling analysis to determine Tc. We examine the different behaviors associated with Hubbard-Stratonovich auxiliary field configurations on both the entire space-time lattice and on a single imaginary time slice, or other quantities, such as equal-time Green's and pair-pair correlation functions.

  2. Interactions in the ionic liquid [EMIM][FAP]: a coupled experimental and computational analysis.

    PubMed

    Voroshylova, Iuliia V; Teixeira, Filipe; Costa, Renata; Pereira, Carlos M; Cordeiro, M Natália D S

    2016-01-28

    Gas-phase electronic and structural properties of the room temperature ionic liquid 1-ethyl-3-methylimidazolium tris(perfluoroethyl)trifluorophosphate ([EMIM][FAP]) were studied using density functional theory, and confirmed with results from infrared spectroscopy. A conformational analysis allowed the identification of several plausible conformers of the ion pairs. For the detected conformers, the infrared spectra were predicted and their thermodynamic properties were evaluated. The topology of the electronic density of the most stable conformers of [EMIM][FAP] ion pairs were characterised using the quantum theory of atoms in molecules. A number of possible hydrogen bonds between the cations and anions of the ionic liquid were identified. Excellent correspondence was found between the predicted spectra of gas-phase [EMIM][FAP] conformers and the experimental infrared spectrum, which in turn allowed a clear attribution of the vibration modes of [EMIM][FAP]. Finally, the contribution of the various conformers of both isomers of the [FAP](-) anion to the ionic liquid macro-properties is shown.

  3. Multiple re-encounter approach to radical pair reactions and the role of nonlinear master equations.

    PubMed

    Clausen, Jens; Guerreschi, Gian Giacomo; Tiersch, Markus; Briegel, Hans J

    2014-08-07

    We formulate a multiple-encounter model of the radical pair mechanism that is based on a random coupling of the radical pair to a minimal model environment. These occasional pulse-like couplings correspond to the radical encounters and give rise to both dephasing and recombination. While this is in agreement with the original model of Haberkorn and its extensions that assume additional dephasing, we show how a nonlinear master equation may be constructed to describe the conditional evolution of the radical pairs prior to the detection of their recombination. We propose a nonlinear master equation for the evolution of an ensemble of independently evolving radical pairs whose nonlinearity depends on the record of the fluorescence signal. We also reformulate Haberkorn's original argument on the physicality of reaction operators using the terminology of quantum optics/open quantum systems. Our model allows one to describe multiple encounters within the exponential model and connects this with the master equation approach. We include hitherto neglected effects of the encounters, such as a separate dephasing in the triplet subspace, and predict potential new effects, such as Grover reflections of radical spins, that may be observed if the strength and time of the encounters can be experimentally controlled.

  4. Coarse-grained modeling of polyethylene melts: Effect on dynamics

    DOE PAGES

    Peters, Brandon L.; Salerno, K. Michael; Agrawal, Anupriya; ...

    2017-05-23

    The distinctive viscoelastic behavior of polymers results from a coupled interplay of motion on multiple length and time scales. Capturing the broad time and length scales of polymer motion remains a challenge. Using polyethylene (PE) as a model macromolecule, we construct coarse-grained (CG) models of PE with three to six methyl groups per CG bead and probe two critical aspects of the technique: pressure corrections required after iterative Boltzmann inversion (IBI) to generate CG potentials that match the pressure of reference fully atomistic melt simulations and the transferability of CG potentials across temperatures. While IBI produces nonbonded pair potentials thatmore » give excellent agreement between the atomistic and CG pair correlation functions, the resulting pressure for the CG models is large compared with the pressure of the atomistic system. We find that correcting the potential to match the reference pressure leads to nonbonded interactions with much deeper minima and slightly smaller effective bead diameter. However, simulations with potentials generated by IBI and pressure-corrected IBI result in similar mean-square displacements (MSDs) and stress autocorrelation functions G( t) for PE melts. While the time rescaling factor required to match CG and atomistic models is the same for pressure- and non-pressure-corrected CG models, it strongly depends on temperature. Furthermore, transferability was investigated by comparing the MSDs and stress autocorrelation functions for potentials developed at different temperatures.« less

  5. Coarse-grained modeling of polyethylene melts: Effect on dynamics

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

    Peters, Brandon L.; Salerno, K. Michael; Agrawal, Anupriya

    The distinctive viscoelastic behavior of polymers results from a coupled interplay of motion on multiple length and time scales. Capturing the broad time and length scales of polymer motion remains a challenge. Using polyethylene (PE) as a model macromolecule, we construct coarse-grained (CG) models of PE with three to six methyl groups per CG bead and probe two critical aspects of the technique: pressure corrections required after iterative Boltzmann inversion (IBI) to generate CG potentials that match the pressure of reference fully atomistic melt simulations and the transferability of CG potentials across temperatures. While IBI produces nonbonded pair potentials thatmore » give excellent agreement between the atomistic and CG pair correlation functions, the resulting pressure for the CG models is large compared with the pressure of the atomistic system. We find that correcting the potential to match the reference pressure leads to nonbonded interactions with much deeper minima and slightly smaller effective bead diameter. However, simulations with potentials generated by IBI and pressure-corrected IBI result in similar mean-square displacements (MSDs) and stress autocorrelation functions G( t) for PE melts. While the time rescaling factor required to match CG and atomistic models is the same for pressure- and non-pressure-corrected CG models, it strongly depends on temperature. Furthermore, transferability was investigated by comparing the MSDs and stress autocorrelation functions for potentials developed at different temperatures.« less

  6. Multiconfiguration pair-density functional theory for doublet excitation energies and excited state geometries: the excited states of CN.

    PubMed

    Bao, Jie J; Gagliardi, Laura; Truhlar, Donald G

    2017-11-15

    Multiconfiguration pair-density functional theory (MC-PDFT) is a post multiconfiguration self-consistent field (MCSCF) method with similar performance to complete active space second-order perturbation theory (CASPT2) but with greater computational efficiency. Cyano radical (CN) is a molecule whose spectrum is well established from experiments and whose excitation energies have been used as a testing ground for theoretical methods to treat excited states of open-shell systems, which are harder and much less studied than excitation energies of closed-shell singlets. In the present work, we studied the adiabatic excitation energies of CN with MC-PDFT. Then we compared this multireference (MR) method to some single-reference (SR) methods, including time-dependent density functional theory (TDDFT) and completely renormalized equation-of-motion coupled-cluster theory with singles, doubles and noniterative triples [CR-EOM-CCSD(T)]; we also compared to some other MR methods, including configuration interaction singles and doubles (MR-CISD) and multistate CASPT2 (MS-CASPT2). Through a comparison between SR and MR methods, we achieved a better appreciation of the need to use MR methods to accurately describe higher excited states, and we found that among the MR methods, MC-PDFT stands out for its accuracy for the first four states out of the five doublet states studied this paper; this shows its efficiency for calculating doublet excited states.

  7. Cooperative Lewis pairs based on late transition metals: activation of small molecules by platinum(0) and B(C6 F5 )3.

    PubMed

    Forrest, Sebastian J K; Clifton, Jamie; Fey, Natalie; Pringle, Paul G; Sparkes, Hazel A; Wass, Duncan F

    2015-02-09

    A Lewis basic platinum(0)-CO complex supported by a diphosphine ligand and B(C6 F5 )3 act cooperatively, in a manner reminiscent of a frustrated Lewis pair, to activate small molecules such as hydrogen, CO2 , and ethene. This cooperative Lewis pair facilitates the coupling of CO and ethene in a new way. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. 76 FR 56745 - Notice of Availability of Government-Owned Inventions; Available for Licensing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-14

    ... No. 12/175262: Coupled Electric Field Sensors for DC Target Electric Field Detection; U.S. Patent Application No. 12/732023: Coupled Bi-Stable Microcircuit System for Ultra-Sensitive Electrical and Magnetic... Electric Field Sensing Utilizing Differential Transistors Pairs. FOR FURTHER INFORMATION CONTACT: Brian Suh...

  9. Large dimensions and small curvatures from supersymmetric brane back-reaction

    NASA Astrophysics Data System (ADS)

    Burgess, C. P.; van Nierop, L.

    2011-04-01

    We compute the back-reaction of pairs of codimension-two branes within an explicit flux-stabilized compactification, to trace how its properties depend on the parameters that define the brane-bulk couplings. Both brane tension and magnetic couplings to the stabilizing flux play an important role in the resulting dynamics, with the magnetic coupling allowing some of the flux to be localized on the branes (thus changing the flux-quantization conditions). We find that back-reaction lifts the classical flat directions of the bulk supergravity, and we calculate both the scalar potential and changes to the extra-dimensional and on-brane geometries that result, as functions of the assumed brane couplings. When linearized about simple rugby-ball geometries the resulting solutions allow a systematic exploration of the system's response. Several of the systems we explore have remarkable properties. Among these are a propensity for the extra dimensions to stabilize at exponentially large sizes, providing a mechanism for generating extremely large volumes. In some circumstances the brane-dilaton coupling allows the bulk dilaton to adjust to suppress the on-brane curvature parametrically below the change in brane tension, potentially providing a mechanism for reducing the vacuum energy. We explore the stability of this suppression to quantum effects in the case where their strength is controlled by the value of the field along the classical flat direction, and find it can (but need not) be stable.

  10. Level indicator for pressure vessels

    DOEpatents

    Not Available

    1982-04-28

    A liquid-level monitor for tracking the level of a coal slurry in a high-pressure vessel including a toroidal-shaped float with magnetically permeable bands thereon disposed within the vessel, two pairs of magnetic-field generators and detectors disposed outside the vessel adjacent the top and bottom thereof and magnetically coupled to the magnetically permeable bands on the float, and signal-processing circuitry for combining signals from the top and bottom detectors for generating a monotonically increasing analog control signal which is a function of liquid level. The control signal may be utilized to operate high-pressure control valves associated with processes in which the high-pressure vessel is used.

  11. High pressure liquid level monitor

    DOEpatents

    Bean, Vern E.; Long, Frederick G.

    1984-01-01

    A liquid level monitor for tracking the level of a coal slurry in a high-pressure vessel including a toroidal-shaped float with magnetically permeable bands thereon disposed within the vessel, two pairs of magnetic field generators and detectors disposed outside the vessel adjacent the top and bottom thereof and magnetically coupled to the magnetically permeable bands on the float, and signal processing circuitry for combining signals from the top and bottom detectors for generating a monotonically increasing analog control signal which is a function of liquid level. The control signal may be utilized to operate high-pressure control valves associated with processes in which the high-pressure vessel is used.

  12. Josephson current through a quantum dot molecule with a Majorana zero mode and Andreev bound states

    NASA Astrophysics Data System (ADS)

    Tang, Han-Zhao; Zhang, Ying-Tao; Liu, Jian-Jun

    2018-04-01

    Based on the Green's function method, we investigate the interplay between Majorana zero mode (MZM) and Andreev bound states (ABSs) in a quantum dot molecule side coupled to a topological superconducting nanowire with a pair of MZMs forming a Josephson junction. Since the strong electron-hole asymmetry induced by the nanowire with a topologically non-trivial phase, the MZM suppress the ABSs. The suppression induced by the MZM is robust against the Coulomb repulsion. The interplay between the MZM and the ABSs in Josephson junction presents a feasible experimental means for distinguish between the presence of MZM and ABSs.

  13. Charge Fluctuations in the NdO1-xFxBiS2 Superconductors

    NASA Astrophysics Data System (ADS)

    Athauda, Anushika; Mizuguchi, Yoshikazu; Nagao, Masanori; Neuefeind, Joerg; Louca, Despina

    2017-12-01

    The local atomic structure of superconducting NdO1-xFxBiS2 (x = 0.2 and 0.4) is investigated using neutron diffraction and the pair density function analysis technique. In the non-superconducting x = 0.2 composition, ferrodistortive displacements of the pyramidal sulfur ions break the tetragonal symmetry and a superlattice structure emerges with peaks appearing at h + k odd reflections superimposed on the even reflections of the P4/nmm symmetry. In the superconducting x = 0.4 composition, similar ferrodistortive displacements are observed but with different magnitudes coupled with in-plane Bi distortions which are indicative of charge fluctuations.

  14. Phonon coupling in optical transitions for singlet-triplet pairs of bound excitons in semiconductors

    NASA Astrophysics Data System (ADS)

    Pistol, M. E.; Monemar, B.

    1986-05-01

    A model is presented for the observed strong difference in selection rules for coupling of phonons in the one-phonon sideband of optical spectra related to bound excitons in semiconductors. The present treatment is specialized to the case of a closely spaced pair of singlet-triplet character as the lowest electronic states, as is common for bound excitons associated with neutral complexes in materials like GaP and Si. The optical transition for the singlet bound-exciton state is found to couple strongly only to symmetric A1 modes. The triplet state has a similar coupling strength to A1 modes, but in addition strong contributions are found for replicas corresponding to high-density-of-states phonons TAX, LAX, and TOX. This can be explained by a treatment of particle-phonon coupling beyond the ordinary adiabatic approximation. A weak mixing between the singlet and triplet states is mediated by the phonon coupling, as described in first-order perturbation theory. The model derived in this work, for such phonon-induced mixing of closely spaced electronic states, is shown to explain the observed phonon coupling for several bound-exciton systems of singlet-triplet character in GaP. In addition, the observed oscillator strength of the forbidden triplet state may be explained as partly derived from phonon-induced mixing with the singlet state, which has a much larger oscillator strength.

  15. Sequence-dependent nucleosome sliding in rotation-coupled and uncoupled modes revealed by molecular simulations

    PubMed Central

    Tan, Cheng; Takada, Shoji

    2017-01-01

    While nucleosome positioning on eukaryotic genome play important roles for genetic regulation, molecular mechanisms of nucleosome positioning and sliding along DNA are not well understood. Here we investigated thermally-activated spontaneous nucleosome sliding mechanisms developing and applying a coarse-grained molecular simulation method that incorporates both long-range electrostatic and short-range hydrogen-bond interactions between histone octamer and DNA. The simulations revealed two distinct sliding modes depending on the nucleosomal DNA sequence. A uniform DNA sequence showed frequent sliding with one base pair step in a rotation-coupled manner, akin to screw-like motions. On the contrary, a strong positioning sequence, the so-called 601 sequence, exhibits rare, abrupt transitions of five and ten base pair steps without rotation. Moreover, we evaluated the importance of hydrogen bond interactions on the sliding mode, finding that strong and weak bonds favor respectively the rotation-coupled and -uncoupled sliding movements. PMID:29194442

  16. μ SR Investigation of Superconducting PbTaSe2

    NASA Astrophysics Data System (ADS)

    Wilson, Murray; Hallas, Alannah; Cai, Yipeng; Guo, Shengli; Gong, Zizhou; Ali, Mazhar; Cava, Robert; Uemura, Yasutomo; Luke, Graeme

    Noncentrosymmetric superconductors are a topic of considerable interest in the condensed matter physics community. These materials have the potential to exhibit exotic superconducting states, particularly in the presence of strong spin orbit coupling. PbTaSe2 is a noncentrosymmetric material which has very strong spin orbit coupling, and is superconducting with a TC of 3.6 K. Previous studies of this material have identified exotic properties such as Dirac cones gapped by spin-orbit coupling, a topological semi-metal state, and possible multi-band superconductivity. To further explore this material, it is of considerable interest to investigate the pairing symmetry of the superconducting state, and determine whether odd-parity superconductivity may exist. In this talk we will present a μSR investigation of the penetration depth temperature dependece to infer the pairing symmetry. We will also present zero field μSR measurements which suggest that this material has an even-parity superconducting state.

  17. Apparatuses and method for converting electromagnetic radiation to direct current

    DOEpatents

    Kotter, Dale K; Novack, Steven D

    2014-09-30

    An energy conversion device may include a first antenna and a second antenna configured to generate an AC current responsive to incident radiation, at least one stripline, and a rectifier coupled with the at least one stripline along a length of the at least one stripline. An energy conversion device may also include an array of nanoantennas configured to generate an AC current in response to receiving incident radiation. Each nanoantenna of the array includes a pair of resonant elements, and a shared rectifier operably coupled to the pair of resonant elements, the shared rectifier configured to convert the AC current to a DC current. The energy conversion device may further include a bus structure operably coupled with the array of nanoantennas and configured to receive the DC current from the array of nanoantennas and transmit the DC current away from the array of nanoantennas.

  18. Spectral analysis of pair-correlation bandwidth: application to cell biology images.

    PubMed

    Binder, Benjamin J; Simpson, Matthew J

    2015-02-01

    Images from cell biology experiments often indicate the presence of cell clustering, which can provide insight into the mechanisms driving the collective cell behaviour. Pair-correlation functions provide quantitative information about the presence, or absence, of clustering in a spatial distribution of cells. This is because the pair-correlation function describes the ratio of the abundance of pairs of cells, separated by a particular distance, relative to a randomly distributed reference population. Pair-correlation functions are often presented as a kernel density estimate where the frequency of pairs of objects are grouped using a particular bandwidth (or bin width), Δ>0. The choice of bandwidth has a dramatic impact: choosing Δ too large produces a pair-correlation function that contains insufficient information, whereas choosing Δ too small produces a pair-correlation signal dominated by fluctuations. Presently, there is little guidance available regarding how to make an objective choice of Δ. We present a new technique to choose Δ by analysing the power spectrum of the discrete Fourier transform of the pair-correlation function. Using synthetic simulation data, we confirm that our approach allows us to objectively choose Δ such that the appropriately binned pair-correlation function captures known features in uniform and clustered synthetic images. We also apply our technique to images from two different cell biology assays. The first assay corresponds to an approximately uniform distribution of cells, while the second assay involves a time series of images of a cell population which forms aggregates over time. The appropriately binned pair-correlation function allows us to make quantitative inferences about the average aggregate size, as well as quantifying how the average aggregate size changes with time.

  19. Calculation of electronic coupling matrix elements for ground and excited state electron transfer reactions: Comparison of the generalized Mulliken-Hush and block diagonalization methods

    NASA Astrophysics Data System (ADS)

    Cave, Robert J.; Newton, Marshall D.

    1997-06-01

    Two independent methods are presented for the nonperturbative calculation of the electronic coupling matrix element (Hab) for electron transfer reactions using ab initio electronic structure theory. The first is based on the generalized Mulliken-Hush (GMH) model, a multistate generalization of the Mulliken Hush formalism for the electronic coupling. The second is based on the block diagonalization (BD) approach of Cederbaum, Domcke, and co-workers. Detailed quantitative comparisons of the two methods are carried out based on results for (a) several states of the system Zn2OH2+ and (b) the low-lying states of the benzene-Cl atom complex and its contact ion pair. Generally good agreement between the two methods is obtained over a range of geometries. Either method can be applied at an arbitrary nuclear geometry and, as a result, may be used to test the validity of the Condon approximation. Examples of nonmonotonic behavior of the electronic coupling as a function of nuclear coordinates are observed for Zn2OH2+. Both methods also yield a natural definition of the effective distance (rDA) between donor (D) and acceptor (A) sites, in contrast to earlier approaches which required independent estimates of rDA, generally based on molecular structure data.

  20. Experimental extraction of an entangled photon pair from two identically decohered pairs.

    PubMed

    Yamamoto, Takashi; Koashi, Masato; Ozdemir, Sahin Kaya; Imoto, Nobuyuki

    2003-01-23

    Entanglement is considered to be one of the most important resources in quantum information processing schemes, including teleportation, dense coding and entanglement-based quantum key distribution. Because entanglement cannot be generated by classical communication between distant parties, distribution of entangled particles between them is necessary. During the distribution process, entanglement between the particles is degraded by the decoherence and dissipation processes that result from unavoidable coupling with the environment. Entanglement distillation and concentration schemes are therefore needed to extract pairs with a higher degree of entanglement from these less-entangled pairs; this is accomplished using local operations and classical communication. Here we report an experimental demonstration of extraction of a polarization-entangled photon pair from two decohered photon pairs. Two polarization-entangled photon pairs are generated by spontaneous parametric down-conversion and then distributed through a channel that induces identical phase fluctuations to both pairs; this ensures that no entanglement is available as long as each pair is manipulated individually. Then, through collective local operations and classical communication we extract from the two decohered pairs a photon pair that is observed to be polarization-entangled.

  1. High-Voltage-Input Level Translator Using Standard CMOS

    NASA Technical Reports Server (NTRS)

    Yager, Jeremy A.; Mojarradi, Mohammad M.; Vo, Tuan A.; Blalock, Benjamin J.

    2011-01-01

    proposed integrated circuit would translate (1) a pair of input signals having a low differential potential and a possibly high common-mode potential into (2) a pair of output signals having the same low differential potential and a low common-mode potential. As used here, "low" and "high" refer to potentials that are, respectively, below or above the nominal supply potential (3.3 V) at which standard complementary metal oxide/semiconductor (CMOS) integrated circuits are designed to operate. The input common-mode potential could lie between 0 and 10 V; the output common-mode potential would be 2 V. This translation would make it possible to process the pair of signals by use of standard 3.3-V CMOS analog and/or mixed-signal (analog and digital) circuitry on the same integrated-circuit chip. A schematic of the circuit is shown in the figure. Standard 3.3-V CMOS circuitry cannot withstand input potentials greater than about 4 V. However, there are many applications that involve low-differential-potential, high-common-mode-potential input signal pairs and in which standard 3.3-V CMOS circuitry, which is relatively inexpensive, would be the most appropriate circuitry for performing other functions on the integrated-circuit chip that handles the high-potential input signals. Thus, there is a need to combine high-voltage input circuitry with standard low-voltage CMOS circuitry on the same integrated-circuit chip. The proposed circuit would satisfy this need. In the proposed circuit, the input signals would be coupled into both a level-shifting pair and a common-mode-sensing pair of CMOS transistors. The output of the level-shifting pair would be fed as input to a differential pair of transistors. The resulting differential current output would pass through six standoff transistors to be mirrored into an output branch by four heterojunction bipolar transistors. The mirrored differential current would be converted back to potential by a pair of diode-connected transistors, which, by virtue of being identical to the input transistors, would reproduce the input differential potential at the output

  2. Spin polarization transfer by the radical pair mechanism

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

    Zarea, Mehdi, E-mail: m-zarea@northwestern.edu; Ratner, Mark A.; Wasielewski, Michael R.

    2015-08-07

    In a three-site representation, we study a spin polarization transfer from radical pair spins to a nearby electron or nuclear spin. The quantum dynamics of the radical pair spins is governed by a constant exchange interaction between the radical pair spins which have different Zeeman frequencies. Radical pair spins can recombine to the singlet ground state or to lower energy triplet states. It is then shown that the coherent dynamics of the radical pair induces spin polarization on the nearby third spin in the presence of a magnetic field. The spin polarization transfer depends on the difference between Zeeman frequencies,more » the singlet and triplet recombination rates, and on the exchange and dipole-dipole interactions between the different spins. In particular, the sign of the polarization depends on the exchange coupling between radical pair spins and also on the difference between singlet and triplet recombination rate constants.« less

  3. Instabilities of coupled Cu2O5 ladders

    NASA Astrophysics Data System (ADS)

    Schuetz, Florian; Marston, Brad

    2008-03-01

    The spin-ladder compound Sr14-xCaxCu24O41 has a complex phase diagram including charge-density-wave order as well as unconventional superconductivity under high pressure. Due to its quasi-one-dimensional natureootnotetextS. Lee, J. B. Marston, J. O. Fjaerestad, Phys. Rev. B 72, 075126. fundamental questions about the high-Tc cuprates might be more easily addressed in this context. However, due to the spatial proximity of neighboring ladders inter-ladder Coulomb repulsion as well as hopping between ladders might still be important. Using the functional renormalization groupootnotetextM. Salmhofer and C. Honerkamp, Prog. Theor. Physics 105, 1 (2001). and an analysis of generalized susceptibilities ootnotetextD. Zanchi and H. J. Schulz, Phys. Rev. B 61, 13609 (2000); C. J. Halboth and W. Metzner, Phys. Rev. Lett. 85, 5162 (2000)., we study a model of coupled Cu2O5 ladders ootnotetextK. Wohlfeld, A. M. Oles, and G. A. Sawatzky, Phys. Rev. B 75, 180501(R) (2007).. We investigate instabilities towards charge, spin, and pairing order as a function of hole doping, inter-ladder hopping, and interaction strength starting from experimentally relevant hopping parametersootnotetextT. F. A. Müller, et al., Phys. Rev. B 57, R12655 (1998)..

  4. On the stability analysis of a pair of van der Pol oscillators with delayed self-connection, position and velocity couplings

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

    Hu, Kun; Department of Mathematics, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon; Chung, Kwok-wai, E-mail: makchung@cityu.edu.hk

    2013-11-15

    In this paper, we perform a stability analysis of a pair of van der Pol oscillators with delayed self-connection, position and velocity couplings. Bifurcation diagram of the damping, position and velocity coupling strengths is constructed, which gives insight into how stability boundary curves come into existence and how these curves evolve from small closed loops into open-ended curves. The van der Pol oscillator has been considered by many researchers as the nodes for various networks. It is inherently unstable at the zero equilibrium. Stability control of a network is always an important problem. Currently, the stabilization of the zero equilibriummore » of a pair of van der Pol oscillators can be achieved only for small damping strength by using delayed velocity coupling. An interesting question arises naturally: can the zero equilibrium be stabilized for an arbitrarily large value of the damping strength? We prove that it can be. In addition, a simple condition is given on how to choose the feedback parameters to achieve such goal. We further investigate how the in-phase mode or the out-of-phase mode of a periodic solution is related to the stability boundary curve that it emerges from a Hopf bifurcation. Analytical expression of a periodic solution is derived using an integration method. Some illustrative examples show that the theoretical prediction and numerical simulation are in good agreement.« less

  5. Role of degeneracy, hybridization, and nesting in the properties of multiorbital systems

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

    Nicholson, Andrew D; Liu, Jia-Ming; Ge, Weihao

    2011-01-01

    To understand the role that degeneracy, hybridization, and nesting play in the magnetic and pairing properties of multiorbital Hubbard models we here study numerically two types of two-orbital models, both with holelike and electron-like Fermi surfaces (FS s) that are related by nesting vectors ( ,0) and (0, ). In one case the bands that determine the FS s arise from strongly hybridized degenerate dxz and dyz orbitals, while in the other the two bands are determined by nondegenerate and nonhybridized s-like orbitals. Using a variety of techniques, in the weak-coupling regime it is shown that only the model withmore » hybridized bands develops metallic magnetic order, while the other model exhibits an ordered excitonic orbital-transverse spin state that is insulating and does not have a local magnetization. However, both models display similar insulating magnetic stripe ordering in the strong-coupling limit. These results indicate that nesting is a necessary but not sufficient condition for the development of ordered states with finite local magnetization in multiorbital Hubbard systems; the additional ingredient appears to be that the nested portions of the bands need to have the same orbital flavor. This condition can be achieved via strong hybridization of the orbitals in weak coupling or via the FS reconstruction induced by the Coulomb interactions in the strong-coupling regime. This effect also affects the pairing symmetry as demonstrated by the study of the dominant pairing channels for the two models.« less

  6. Are Human Mating Preferences with Respect to Height Reflected in Actual Pairings?

    PubMed Central

    Stulp, Gert; Buunk, Abraham P.; Pollet, Thomas V.; Nettle, Daniel; Verhulst, Simon

    2013-01-01

    Pair formation, acquiring a mate to form a reproductive unit, is a complex process. Mating preferences are a step in this process. However, due to constraining factors such as availability of mates, rival competition, and mutual mate choice, preferred characteristics may not be realised in the actual partner. People value height in their partner and we investigated to what extent preferences for height are realised in actual couples. We used data from the Millennium Cohort Study (UK) and compared the distribution of height difference in actual couples to simulations of random mating to test how established mate preferences map on to actual mating patterns. In line with mate preferences, we found evidence for: (i) assortative mating (r = .18), (ii) the male-taller norm, and, for the first time, (iii) for the male-not-too-tall norm. Couples where the male partner was shorter, or over 25 cm taller than the female partner, occurred at lower frequency in actual couples than expected by chance, but the magnitude of these effects was modest. We also investigated another preference rule, namely that short women (and tall men) prefer large height differences with their partner, whereas tall women (and short men) prefer small height differences. These patterns were also observed in our population, although the strengths of these associations were weaker than previously reported strength of preferences. We conclude that while preferences for partner height generally translate into actual pairing, they do so only modestly. PMID:23342102

  7. Are human mating preferences with respect to height reflected in actual pairings?

    PubMed

    Stulp, Gert; Buunk, Abraham P; Pollet, Thomas V; Nettle, Daniel; Verhulst, Simon

    2013-01-01

    Pair formation, acquiring a mate to form a reproductive unit, is a complex process. Mating preferences are a step in this process. However, due to constraining factors such as availability of mates, rival competition, and mutual mate choice, preferred characteristics may not be realised in the actual partner. People value height in their partner and we investigated to what extent preferences for height are realised in actual couples. We used data from the Millennium Cohort Study (UK) and compared the distribution of height difference in actual couples to simulations of random mating to test how established mate preferences map on to actual mating patterns. In line with mate preferences, we found evidence for: (i) assortative mating (r = .18), (ii) the male-taller norm, and, for the first time, (iii) for the male-not-too-tall norm. Couples where the male partner was shorter, or over 25 cm taller than the female partner, occurred at lower frequency in actual couples than expected by chance, but the magnitude of these effects was modest. We also investigated another preference rule, namely that short women (and tall men) prefer large height differences with their partner, whereas tall women (and short men) prefer small height differences. These patterns were also observed in our population, although the strengths of these associations were weaker than previously reported strength of preferences. We conclude that while preferences for partner height generally translate into actual pairing, they do so only modestly.

  8. Causal manipulation of functional connectivity in a specific neural pathway during behaviour and at rest

    PubMed Central

    Johnen, Vanessa M; Neubert, Franz-Xaver; Buch, Ethan R; Verhagen, Lennart; O'Reilly, Jill X; Mars, Rogier B; Rushworth, Matthew F S

    2015-01-01

    Correlations in brain activity between two areas (functional connectivity) have been shown to relate to their underlying structural connections. We examine the possibility that functional connectivity also reflects short-term changes in synaptic efficacy. We demonstrate that paired transcranial magnetic stimulation (TMS) near ventral premotor cortex (PMv) and primary motor cortex (M1) with a short 8-ms inter-pulse interval evoking synchronous pre- and post-synaptic activity and which strengthens interregional connectivity between the two areas in a pattern consistent with Hebbian plasticity, leads to increased functional connectivity between PMv and M1 as measured with functional magnetic resonance imaging (fMRI). Moreover, we show that strengthening connectivity between these nodes has effects on a wider network of areas, such as decreasing coupling in a parallel motor programming stream. A control experiment revealed that identical TMS pulses at identical frequencies caused no change in fMRI-measured functional connectivity when the inter-pulse-interval was too long for Hebbian-like plasticity. DOI: http://dx.doi.org/10.7554/eLife.04585.001 PMID:25664941

  9. Light bullets in coupled nonlinear Schrödinger equations with variable coefficients and a trapping potential.

    PubMed

    Xu, Si-Liu; Zhao, Guo-Peng; Belić, Milivoj R; He, Jun-Rong; Xue, Li

    2017-04-17

    We analyze three-dimensional (3D) vector solitary waves in a system of coupled nonlinear Schrödinger equations with spatially modulated diffraction and nonlinearity, under action of a composite self-consistent trapping potential. Exact vector solitary waves, or light bullets (LBs), are found using the self-similarity method. The stability of vortex 3D LB pairs is examined by direct numerical simulations; the results show that only low-order vortex soliton pairs with the mode parameter values n ≤ 1, l ≤ 1 and m = 0 can be supported by the spatially modulated interaction in the composite trap. Higher-order LBs are found unstable over prolonged distances.

  10. Cooperation driven coherence: Brains working hard together.

    PubMed

    Bezerianos, Anastasios; Sun, Yu; Chen, Yu; Woong, Kian Fong; Taya, Fumihiko; Arico, Pietro; Borghini, Gianluca; Babiloni, Fabio; Thakor, Nitish

    2015-01-01

    The current study aims to look at the difference in coupling of EEG activity of participant pairs while they perform a cooperative, concurrent, independent yet different task at high and low difficulty levels. Participants performed the National Aeronautics and Space Administration (NASA) designed Multi-Attribute Task Battery (MATB-II) task which simulates a pilot and copilot operating an aircraft. Each participant in the pair was responsible for 2 out of 4 subtasks which were independent and different from one another while all tasks occurs concurrently in real time with difficulty levels being the frequency that adjustments are required for each subtask. We found that as the task become more difficult, there was more coupling between the pilot and copilot.

  11. NLO QCD effective field theory analysis of W +W - production at the LHC including fermionic operators

    DOE PAGES

    Baglio, Julien; Dawson, Sally; Lewis, Ian M.

    2017-10-03

    In this paper, we study the impact of anomalous gauge boson and fermion couplings on the production of W +W - pairs at the LHC. Helicity amplitudes are presented separately to demonstrate the sources of new physics contributions and the impact of QCD and electroweak corrections. The QCD corrections have important effects on the fits to anomalous couplings, in particular when one W boson is longitudinally polarized and the other is transversely polarized. In effective field theory language, we demonstrate that the dimension-6 approximation to constraining new physics effects in W +W - pair production fails at p T ~more » 500 - 1000 GeV.« less

  12. Mass spectrometry based on a coupled Cooper-pair box and nanomechanical resonator system

    NASA Astrophysics Data System (ADS)

    Jiang, Cheng; Chen, Bin; Li, Jin-Jin; Zhu, Ka-Di

    2011-10-01

    Nanomechanical resonators (NRs) with very high frequency have a great potential for mass sensing with unprecedented sensitivity. In this study, we propose a scheme for mass sensing based on the NR capacitively coupled to a Cooper-pair box (CPB) driven by two microwave currents. The accreted mass landing on the resonator can be measured conveniently by tracking the resonance frequency shifts because of mass changes in the signal absorption spectrum. We demonstrate that frequency shifts induced by adsorption of ten 1587 bp DNA molecules can be well resolved in the absorption spectrum. Integration with the CPB enables capacitive readout of the mechanical resonance directly on the chip.

  13. Evidence for phononic pairing in extremely overdoped ``pure'' d-wave superconductor Bi2212

    NASA Astrophysics Data System (ADS)

    He, Yu; Hishimoto, Makoto; Song, Dongjoon; Eisaki, Hiroshi; Shen, Zhi-Xun

    2015-03-01

    Recent advancement in High Tc cuprate superconductor research has elucidated strong interaction between superconductivity and competing orders. Therefore, the mechanism behind the 'pure' d-wave superconducting behavior becomes the next stepping stone to further the understanding. We have performed photoemission study on extremely overdoped Bi2212 single crystal synthesized via high pressure method. In this regime, we demonstrate the much reduced superconducting gap and the absence of pseudogap. Clear gap shifted bosonic mode coupling is observed throughout the entire Brillouin zone. Via full Eliashberg treatment, we find the electron-phonon coupling strength capable of producing a transition temperature very close to Tc. This strongly implies bosonic contribution to cuprate superconductivity's pairing glue.

  14. NLO QCD effective field theory analysis of W +W - production at the LHC including fermionic operators

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

    Baglio, Julien; Dawson, Sally; Lewis, Ian M.

    In this paper, we study the impact of anomalous gauge boson and fermion couplings on the production of W +W - pairs at the LHC. Helicity amplitudes are presented separately to demonstrate the sources of new physics contributions and the impact of QCD and electroweak corrections. The QCD corrections have important effects on the fits to anomalous couplings, in particular when one W boson is longitudinally polarized and the other is transversely polarized. In effective field theory language, we demonstrate that the dimension-6 approximation to constraining new physics effects in W +W - pair production fails at p T ~more » 500 - 1000 GeV.« less

  15. Loop electrostatics modulates the intersubunit interactions in ferritin.

    PubMed

    Bernacchioni, Caterina; Ghini, Veronica; Pozzi, Cecilia; Di Pisa, Flavio; Theil, Elizabeth C; Turano, Paola

    2014-11-21

    Functional ferritins are 24-mer nanocages that self-assemble with extended contacts between pairs of 4-helix bundle subunits coupled in an antiparallel fashion along the C2 axes. The largest intersubunit interaction surface in the ferritin nanocage involves helices, but contacts also occur between groups of three residues midway in the long, solvent-exposed L-loops of facing subunits. The anchor points between intersubunit L-loop pairs are the salt bridges between the symmetry-related, conserved residues Asp80 and Lys82. The resulting quaternary structure of the cage is highly soluble and thermostable. Substitution of negatively charged Asp80 with a positively charged Lys in homopolymeric M ferritin introduces electrostatic repulsions that inhibit the oligomerization of the ferritin subunits. D80K ferritin was present in inclusion bodies under standard overexpressing conditions in E. coli, contrasting with the wild type protein. Small amounts of fully functional D80K nanocages formed when expression was slowed. The more positively charged surface results in a different solubility profile and D80K crystallized in a crystal form with a low density packing. The 3D structure of D80K variant is the same as wild type except for the side chain orientations of Lys80 and facing Lys82. When three contiguous Lys groups are introduced in D80KI81K ferritin variant the nanocage assembly is further inhibited leading to lower solubility and reduced thermal stability. Here, we demonstrate that the electrostatic pairing at the center of the L-loops has a specific kinetic role in the self-assembly of ferritin nanocages.

  16. Happy Spouses, Happy Parents? Family Relationships among Finnish and Dutch Dual Earners

    ERIC Educational Resources Information Center

    Malinen, Kaisa; Kinnunen, Ulla; Tolvanen, Asko; Ronka, Anna; Wierda-Boer, Hilde; Gerris, Jan

    2010-01-01

    In this study links between spousal and parent-child relationships among Finnish (n = 157 couples) and Dutch (n = 276 couples) dual earners with young children were examined using paired questionnaire data. Variable-oriented analyses (structural equation modeling with a multigroup procedure) supported the spillover hypothesis, as higher levels of…

  17. First-order dipolar phase transition in the Dicke model with infinitely coordinated frustrating interaction

    NASA Astrophysics Data System (ADS)

    Mukhin, S. I.; Gnezdilov, N. V.

    2018-05-01

    We found analytically a first-order quantum phase transition in a Cooper pair box array of N low-capacitance Josephson junctions capacitively coupled to resonant photons in a microwave cavity. The Hamiltonian of the system maps on the extended Dicke Hamiltonian of N spins 1 /2 with infinitely coordinated antiferromagnetic (frustrating) interaction. This interaction arises from the gauge-invariant coupling of the Josephson-junction phases to the vector potential of the resonant photons field. In the N ≫1 semiclassical limit, we found a critical coupling at which the ground state of the system switches to one with a net collective electric dipole moment of the Cooper pair boxes coupled to a super-radiant equilibrium photonic condensate. This phase transition changes from the first to second order if the frustrating interaction is switched off. A self-consistently "rotating" Holstein-Primakoff representation for the Cartesian components of the total superspin is proposed, that enables one to trace both the first- and the second-order quantum phase transitions in the extended and standard Dicke models, respectively.

  18. Deterministic time-reversible thermostats: chaos, ergodicity, and the zeroth law of thermodynamics

    NASA Astrophysics Data System (ADS)

    Patra, Puneet Kumar; Sprott, Julien Clinton; Hoover, William Graham; Griswold Hoover, Carol

    2015-09-01

    The relative stability and ergodicity of deterministic time-reversible thermostats, both singly and in coupled pairs, are assessed through their Lyapunov spectra. Five types of thermostat are coupled to one another through a single Hooke's-law harmonic spring. The resulting dynamics shows that three specific thermostat types, Hoover-Holian, Ju-Bulgac, and Martyna-Klein-Tuckerman, have very similar Lyapunov spectra in their equilibrium four-dimensional phase spaces and when coupled in equilibrium or nonequilibrium pairs. All three of these oscillator-based thermostats are shown to be ergodic, with smooth analytic Gaussian distributions in their extended phase spaces (coordinate, momentum, and two control variables). Evidently these three ergodic and time-reversible thermostat types are particularly useful as statistical-mechanical thermometers and thermostats. Each of them generates Gibbs' universal canonical distribution internally as well as for systems to which they are coupled. Thus they obey the zeroth law of thermodynamics, as a good heat bath should. They also provide dissipative heat flow with relatively small nonlinearity when two or more such temperature baths interact and provide useful deterministic replacements for the stochastic Langevin equation.

  19. DIRECTIONAL COUPLERS

    DOEpatents

    Nigg, D.J.

    1961-12-01

    A directional coupler of small size is designed. Stripline conductors of non-rectilinear configuration, and separated from each other by a thin dielectric spacer. cross each other at least at two locations at right angles, thus providing practically pure capacitive coupling which substantially eliminates undesirable inductive coupling. The conductors are sandwiched between a pair of ground planes. The coupling factor is dependent only on the thickness and dielectric constant of the dielectric spacer at the point of conductor crossover. (AEC)

  20. A high level Ab initio study of the anionic hydrogen-bonded complexes FH-CN-, FH-NC-, H2O-CN- and H2O-NC-

    NASA Technical Reports Server (NTRS)

    Lee, Timothy J.

    1989-01-01

    HF, H2O, CN- and their hydrogen-bonded complexes were studied using state-of-the-art ab initio quantum mechanical methods. A large Gaussian one particle basis set consisting of triple zeta plus double polarization plus diffuse s and p functions (TZ2P + diffuse) was used. The theoretical methods employed include self consistent field, second order Moller-Plesset perturbation theory, singles and doubles configuration interaction theory and the singles and doubles coupled cluster approach. The FH-CN- and FH-NC- and H2O-CN-, H2O-NC- pairs of complexes are found to be essentially isoenergetic. The first pair of complexes are predicted to be bound by approx. 24 kcal/mole and the latter pair bound by approximately 15 kcal/mole. The ab initio binding energies are in good agreement with the experimental values. The two being shorter than the analogous C-N hydrogen bond. The infrared (IR) spectra of the two pairs of complexes are also very similar, though a severe perturbation of the potential energy surface by proton exchange means that the accurate prediction of the band center of the most intense IR mode requires a high level of electronic structure theory as well as a complete treatment of anharmonic effects. The bonding of anionic hydrogen-bonded complexes is discussed and contrasted with that of neutral hydrogen-bonded complexes.

  1. Search for pair-produced vector-like B quarks in proton-proton collisions at $$\\sqrt{s}$$ = 8 TeV

    DOE PAGES

    Khachatryan, Vardan

    2015-07-28

    A search for the production of a heavy B quark, having electric charge -1/3 and vector couplings to W, Z, and H bosons, is carried out using proton-proton collision data recorded at the CERN LHC by the CMS experiment, corresponding to an integrated luminosity of 19.7 fb -1. The B quark is assumed to be pair-produced and to decay in one of three ways: to tW, bZ, or bH. The search is carried out in final states with one, two, and more than two charged leptons, as well as in fully hadronic final states. Each of the channels in themore » exclusive final-state topologies is designed to be sensitive to specific combinations of the B quark-antiquark pair decays. The observed event yields are found to be consistent with the standard model expectations in all the fi- nal states studied. Our statistical combination of these results was performed and upper limits were set on the cross section of the strongly produced B quark-antiquark pairs as a function of the B quark mass. Additionally, lower limits on the B quark mass between 740 and 900 GeV are set at a 95% confidence level, depending on the values of the branching fractions of the B quark to tW, bZ, and bH. Overall, these limits are the most stringent to date.« less

  2. Oriented covalent immobilization of antibodies for measurement of intermolecular binding forces between zipper-like contact surfaces of split inteins.

    PubMed

    Sorci, Mirco; Dassa, Bareket; Liu, Hongwei; Anand, Gaurav; Dutta, Amit K; Pietrokovski, Shmuel; Belfort, Marlene; Belfort, Georges

    2013-06-18

    In order to measure the intermolecular binding forces between two halves (or partners) of naturally split protein splicing elements called inteins, a novel thiol-hydrazide linker was designed and used to orient immobilized antibodies specific for each partner. Activation of the surfaces was achieved in one step, allowing direct intermolecular force measurement of the binding of the two partners of the split intein (called protein trans-splicing). Through this binding process, a whole functional intein is formed resulting in subsequent splicing. Atomic force microscopy (AFM) was used to directly measure the split intein partner binding at 1 μm/s between native (wild-type) and mixed pairs of C- and N-terminal partners of naturally occurring split inteins from three cyanobacteria. Native and mixed pairs exhibit similar binding forces within the error of the measurement technique (~52 pN). Bioinformatic sequence analysis and computational structural analysis discovered a zipper-like contact between the two partners with electrostatic and nonpolar attraction between multiple aligned ion pairs and hydrophobic residues. Also, we tested the Jarzynski's equality and demonstrated, as expected, that nonequilibrium dissipative measurements obtained here gave larger energies of interaction as compared with those for equilibrium. Hence, AFM coupled with our immobilization strategy and computational studies provides a useful analytical tool for the direct measurement of intermolecular association of split inteins and could be extended to any interacting protein pair.

  3. The limits of the nuclear landscape explored by the relativistic continuum Hartree–Bogoliubov theory

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

    Xia, X. W.; Lim, Y.; Zhao, P. W.

    The ground-state properties of nuclei with 8more » $$\\leqslant$$ Z $$\\leqslant$$ 120 from the proton drip line to the neutron drip line have been investigated using the relativistic continuum Hartree-Bogoliubov (RCHB) theory with the relativistic density functional PC-PK1. With the effects of the continuum included, there are totally 9035 nuclei predicted to be bound, which largely extends the existing nuclear landscapes predicted with other methods. The calculated binding energies, separation energies, neutron and proton Fermi surfaces, root-mean-square (rms) radii of neutron, proton, matter, and charge distributions, ground-state spins and parities are tabulated. The extension of the nuclear landscape obtained with RCHB is discussed in detail, in particular for the neutron-rich side, in comparison with the relativistic mean field calculations without pairing correlations and also other predicted landscapes. Here, it is found that the coupling between the bound states and the continuum due to the pairing correlations plays an essential role in extending the nuclear landscape. The systematics of the separation energies, radii, densities, potentials and pairing energies of the RCHB calculations are also discussed. In addition, the α-decay energies and proton emitters based on the RCHB calculations are investigated.« less

  4. Chemiluminescence assay for the detection of biological warfare agents

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

    Langry, K; Horn, J

    A chemiluminescent homogeneous immunoassay and a hand-size multiassay reader are described that could be used for detecting biological materials. The special feature of the assay is that it employs two different antibodies that each bind to a unique epitope on the same antigen. Each group of epitope-specific antibodies has linked to it an enzyme of a proximal-enzyme pair. One enzyme of the pair utilizes a substrate in high concentration to produce a second substrate required by the second enzyme. This new substrate enables the second enzyme to function. The reaction of the second enzyme is configured to produce light. Thismore » chemiluminescence is detected with a charge-coupled device (CCD) camera. The proximal pair enzymes must be in close proximity to one another to allow the second enzyme to react with the product of the first enzyme. This only occurs when the enzyme-linked antibodies are attached to the antigen, whether antigen is a single protein with multiple epitopes or the surface of a cell with a variety of different antigens. As a result of their juxtaposition, the enzymes produce light only in the presence of the biological material. A brief description is given as to how this assay could be utilized in a personal bio-agent detector system.« less

  5. Correspondence of electroencephalography and near-infrared spectroscopy sensitivities to the cerebral cortex using a high-density layout

    PubMed Central

    Giacometti, Paolo; Diamond, Solomon G.

    2014-01-01

    Abstract. This study investigates the correspondence of the cortical sensitivity of electroencephalography (EEG) and near-infrared spectroscopy (NIRS). EEG forward model sensitivity to the cerebral cortex was calculated for 329 EEG electrodes following the 10-5 EEG positioning system using a segmented structural magnetic resonance imaging scan of a human subject. NIRS forward model sensitivity was calculated for the same subject using 156 NIRS source-detector pairs selected from 32 source and 32 detector optodes positioned on the scalp using a subset of the 10-5 EEG positioning system. Sensitivity correlations between colocalized NIRS source-detector pair groups and EEG channels yielded R=0.46±0.08. Groups of NIRS source-detector pairs with maximum correlations to EEG electrode sensitivities are tabulated. The mean correlation between the point spread functions for EEG and NIRS regions of interest (ROI) was R=0.43±0.07. Spherical ROIs with radii of 26 mm yielded the maximum correlation between EEG and NIRS averaged across all cortical mesh nodes. These sensitivity correlations between EEG and NIRS should be taken into account when designing multimodal studies of neurovascular coupling and when using NIRS as a statistical prior for EEG source localization. PMID:25558462

  6. The limits of the nuclear landscape explored by the relativistic continuum Hartree–Bogoliubov theory

    DOE PAGES

    Xia, X. W.; Lim, Y.; Zhao, P. W.; ...

    2017-11-01

    The ground-state properties of nuclei with 8more » $$\\leqslant$$ Z $$\\leqslant$$ 120 from the proton drip line to the neutron drip line have been investigated using the relativistic continuum Hartree-Bogoliubov (RCHB) theory with the relativistic density functional PC-PK1. With the effects of the continuum included, there are totally 9035 nuclei predicted to be bound, which largely extends the existing nuclear landscapes predicted with other methods. The calculated binding energies, separation energies, neutron and proton Fermi surfaces, root-mean-square (rms) radii of neutron, proton, matter, and charge distributions, ground-state spins and parities are tabulated. The extension of the nuclear landscape obtained with RCHB is discussed in detail, in particular for the neutron-rich side, in comparison with the relativistic mean field calculations without pairing correlations and also other predicted landscapes. Here, it is found that the coupling between the bound states and the continuum due to the pairing correlations plays an essential role in extending the nuclear landscape. The systematics of the separation energies, radii, densities, potentials and pairing energies of the RCHB calculations are also discussed. In addition, the α-decay energies and proton emitters based on the RCHB calculations are investigated.« less

  7. Pair-correlation function of a metastable helium Bose-Einstein condensate

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

    Zin, Pawel; Trippenbach, Marek; Gajda, Mariusz

    2004-02-01

    The pair-correlation function is one of the basic quantities to characterize the coherence properties of a Bose-Einstein condensate. We calculate this function in the experimentally important case of a zero temperature Bose-Einstein condensate in a metastable triplet helium state using the variational method with a pair-excitation ansatz. We compare our result with a pair-correlation function obtained for the hard-sphere potential with the same scattering length. Both functions are practically indistinguishable for distances greater than the scattering length. At smaller distances, due to interatomic interactions, the helium condensate shows strong correlations.

  8. Analysis of fusaric acid in maize using molecularly imprinted solid phase extraction (MISPE) clean-up and ion-pair LC with diode array UV detection

    USDA-ARS?s Scientific Manuscript database

    Fusaric acid is a phytotoxin and mycotoxin occasionally found in maize contaminated with Fusarium fungi. A selective sample clean-up procedure was developed to detect fusaric acid in maize using molecularly imprinted solid phase extraction (MISPE) clean-up coupled with ion-pair liquid chromatography...

  9. General Model of Photon-Pair Detection with an Image Sensor

    NASA Astrophysics Data System (ADS)

    Defienne, Hugo; Reichert, Matthew; Fleischer, Jason W.

    2018-05-01

    We develop an analytic model that relates intensity correlation measurements performed by an image sensor to the properties of photon pairs illuminating it. Experiments using an effective single-photon counting camera, a linear electron-multiplying charge-coupled device camera, and a standard CCD camera confirm the model. The results open the field of quantum optical sensing using conventional detectors.

  10. Semiconductor to metal transition by tuning the location of N{sub 2}{sup AA} in armchair graphene nanoribbons

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

    Chen, Tong; Wang, Ling-Ling, E-mail: llwang@hnu.edu.cn; Li, Quan

    2014-02-07

    The electronic band structures and transport properties of N{sub 2}{sup AA}-doped armchair graphene nanoribbons (aGNRs) with two quasi-adjacent substitutional nitrogen atoms incorporated in pairs of neighboring carbon atoms in the same sublattice A are investigated by using non-equilibrium Green function formalism in combination with density functional theory. The results show that the coupling effect between the Pz orbitals of carbon and nitrogen atoms plays an important role in the transition between semiconductor and metal by different locations of N{sub 2}{sup AA}-doped aGNRs. And the striking negative differential resistance behaviors can be found in such devices. These tremendous properties suggest potentialmore » application of N{sub 2}{sup AA}-doped aGNRs in graphene-based nanoelectronic devices.« less

  11. Calculation of the Full Scattering Amplitude without Partial Wave Decomposition II

    NASA Technical Reports Server (NTRS)

    Shertzer, J.; Temkin, A.

    2003-01-01

    As is well known, the full scattering amplitude can be expressed as an integral involving the complete scattering wave function. We have shown that the integral can be simplified and used in a practical way. Initial application to electron-hydrogen scattering without exchange was highly successful. The Schrodinger equation (SE) can be reduced to a 2d partial differential equation (pde), and was solved using the finite element method. We have now included exchange by solving the resultant SE, in the static exchange approximation. The resultant equation can be reduced to a pair of coupled pde's, to which the finite element method can still be applied. The resultant scattering amplitudes, both singlet and triplet, as a function of angle can be calculated for various energies. The results are in excellent agreement with converged partial wave results.

  12. Synthetic Superconductivity in Single-Layer Crystals

    NASA Astrophysics Data System (ADS)

    Levitov, Leonid; Borgnia, Dan; Lee, Patrick

    2015-03-01

    Electronic states in atomically thin 2D crystals are fully exposed and can couple to extrinsic degrees of freedom via long-range Coulomb interactions. Novel many-body effects in such systems can be engineered by embedding them in a polar environment. Superconducting pairing interaction induced in this way can enhance the intrinsic electron-phonon pairing mechanism. We take on this notion, which was around since the 60's (''excitonic superconductivity''), and consider synthetic superconductivity (SSC) induced in 2D crystals by a polar environment. One interesting aspect of this scenario is that Coulomb repulsion acts as superconductivity friend rather than a foe. Such repulsion-to-attraction transmutation allows to access strong-coupling superconductivity regime even when intrinsic pairing interaction is weak. We analyze pairing interaction in 2D crystals placed atop a highly polarizable dielectric with dispersive permittivity ɛ (ω) and predict that by optimizing system parameters a substantial enhancement can be achieved. We also argue that the SSC mechanism can be responsible, at least in part, for 100 K superconductivity recently observed in FeSe monolayers grown on SrTiO3 substrate, with Tc more than 10 times larger than in bulk 3D FeSe crystals, arxiv:1406.3435.

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

    Sirunyan, Albert M; et al.

    A search is presented for heavy vector-like quarks (VLQs) that couple only to light quarks in proton-proton collisions at sqrt(s) = 8 TeV at the LHC. The data were collected by the CMS experiment during 2012 and correspond to an integrated luminosity of 19.7 inverse femtobarns. Both single and pair production of VLQs are considered. The single-production search is performed for down-type VLQs (electric charge of magnitude 1/3), while the pair-production search is sensitive to up-type (charge of magnitude 2/3) and down-type VLQs. Final states with at least one muon or one electron are considered. No significant excess over standardmore » model expectations is observed, and lower limits on the mass of VLQs are derived. The lower mass limits range from 400 to 1800 GeV, depending on the single-production cross section and the VLQ branching fractions B to W, Z, and Higgs bosons. When considering pair production alone, VLQs with masses below 845 GeV are excluded for B(W) = 1.0, and below 685 GeV for B(W) = 0.5, B(Z) = B(H) = 0.25. The results are more stringent than those previously obtained for single and pair production of VLQs coupled to light quarks.« less

  14. High-energy X-ray focusing and applications to pair distribution function investigation of Pt and Au nanoparticles at high pressures

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

    Hong, Xinguo; Ehm, Lars; Zhong, Zhong

    We report development of micro-focusing optics for high-energy x-rays by combining a sagittally bent Laue crystal monchromator with Kirkpatrick-Baez (K–B) X-ray focusing mirrors. The optical system is able to provide a clean, high-flux X-ray beam suitable for pair distribution function (PDF) measurements at high pressure using a diamond anvil cell (DAC). A focused beam of moderate size (10–15 μm) has been achieved at energies of 66 and 81keV. PDF data for nanocrystalline platinum (n-Pt) were collected at 12.5 GPa with a single 5 s X-ray exposure, showing that the in-situ compression, decompression, and relaxation behavior of samples in the DACmore » can be investigated with this technique. PDFs of n-Pt and nano Au (n-Au) under quasi-hydrostatic loading to as high as 71GPa indicate the existence of substantial reduction of grain or domain size for Pt and Au nanoparticles at pressures below 10 GPa. In conclusion, the coupling of sagittally bent Laue crystals with K–B mirrors provides a useful means to focus high-energy synchrotron X-rays from a bending magnet or wiggler source.« less

  15. High-energy X-ray focusing and applications to pair distribution function investigation of Pt and Au nanoparticles at high pressures

    DOE PAGES

    Hong, Xinguo; Ehm, Lars; Zhong, Zhong; ...

    2016-02-23

    We report development of micro-focusing optics for high-energy x-rays by combining a sagittally bent Laue crystal monchromator with Kirkpatrick-Baez (K–B) X-ray focusing mirrors. The optical system is able to provide a clean, high-flux X-ray beam suitable for pair distribution function (PDF) measurements at high pressure using a diamond anvil cell (DAC). A focused beam of moderate size (10–15 μm) has been achieved at energies of 66 and 81keV. PDF data for nanocrystalline platinum (n-Pt) were collected at 12.5 GPa with a single 5 s X-ray exposure, showing that the in-situ compression, decompression, and relaxation behavior of samples in the DACmore » can be investigated with this technique. PDFs of n-Pt and nano Au (n-Au) under quasi-hydrostatic loading to as high as 71GPa indicate the existence of substantial reduction of grain or domain size for Pt and Au nanoparticles at pressures below 10 GPa. In conclusion, the coupling of sagittally bent Laue crystals with K–B mirrors provides a useful means to focus high-energy synchrotron X-rays from a bending magnet or wiggler source.« less

  16. High-energy X-ray focusing and applications to pair distribution function investigation of Pt and Au nanoparticles at high pressures

    NASA Astrophysics Data System (ADS)

    Hong, Xinguo; Ehm, Lars; Zhong, Zhong; Ghose, Sanjit; Duffy, Thomas S.; Weidner, Donald J.

    2016-02-01

    We report development of micro-focusing optics for high-energy x-rays by combining a sagittally bent Laue crystal monchromator with Kirkpatrick-Baez (K-B) X-ray focusing mirrors. The optical system is able to provide a clean, high-flux X-ray beam suitable for pair distribution function (PDF) measurements at high pressure using a diamond anvil cell (DAC). A focused beam of moderate size (10-15 μm) has been achieved at energies of 66 and 81 keV. PDF data for nanocrystalline platinum (n-Pt) were collected at 12.5 GPa with a single 5 s X-ray exposure, showing that the in-situ compression, decompression, and relaxation behavior of samples in the DAC can be investigated with this technique. PDFs of n-Pt and nano Au (n-Au) under quasi-hydrostatic loading to as high as 71 GPa indicate the existence of substantial reduction of grain or domain size for Pt and Au nanoparticles at pressures below 10 GPa. The coupling of sagittally bent Laue crystals with K-B mirrors provides a useful means to focus high-energy synchrotron X-rays from a bending magnet or wiggler source.

  17. High-energy X-ray focusing and applications to pair distribution function investigation of Pt and Au nanoparticles at high pressures

    PubMed Central

    Hong, Xinguo; Ehm, Lars; Zhong, Zhong; Ghose, Sanjit; Duffy, Thomas S.; Weidner, Donald J.

    2016-01-01

    We report development of micro-focusing optics for high-energy x-rays by combining a sagittally bent Laue crystal monchromator with Kirkpatrick-Baez (K–B) X-ray focusing mirrors. The optical system is able to provide a clean, high-flux X-ray beam suitable for pair distribution function (PDF) measurements at high pressure using a diamond anvil cell (DAC). A focused beam of moderate size (10–15 μm) has been achieved at energies of 66 and 81 keV. PDF data for nanocrystalline platinum (n-Pt) were collected at 12.5 GPa with a single 5 s X-ray exposure, showing that the in-situ compression, decompression, and relaxation behavior of samples in the DAC can be investigated with this technique. PDFs of n-Pt and nano Au (n-Au) under quasi-hydrostatic loading to as high as 71 GPa indicate the existence of substantial reduction of grain or domain size for Pt and Au nanoparticles at pressures below 10 GPa. The coupling of sagittally bent Laue crystals with K–B mirrors provides a useful means to focus high-energy synchrotron X-rays from a bending magnet or wiggler source. PMID:26902122

  18. Mesure des couplages trilineaires anomaux des bosons de jauge avec le detecteur OPAL au LEP

    NASA Astrophysics Data System (ADS)

    Trigger, Isabel Marian

    Since 1996, the Large Electron-Positron collider (LEP) at CERN has run at energies sufficiently high for the pair production of electroweak gauge bosons. This permits stringent new tests of the Standard Model of particle physics, which makes very precise predictions of the force and nature of the couplings between these bosons. Two of the possible production processes for W+W- pairs are e+e - --> Z0/γ --> W+W -, which involve W+W-Z 0 and W+W-γ couplings. A detailed study of W+W- events can be used to verify the non-Abelian nature of electroweak interactions, and also, eventually, to probe for phenomena arising from physics beyond the Standard Model. The existence of certain new heavy particles, for example, might result in anomalous couplings. We measure the W+W-Z0 and W+W-γ couplings directly, from the rate of W+W- production in the OPAL detector and from characteristics of the decay product distributions of these events. There are three possible final states for W+W - decays: (i) two oppositely charged leptons and missing energy (W+W- --> l - n l+ n ); (ii)one charged lepton, two jets and missing energy (W+W- --> qq¯l n ); or (iii)four hadronic jets (W+W - --> qq¯qq¯). This thesis principally describes the four-jet decays. This is a complicated final state to reconstruct, as the kinematics of the event must be used to determine which of three possible jet pairings corresponds to the true W+ and W- , and in order to increase the sensitivity to anomalous couplings, it is also necessary to use the charges and momenta of the hadrons in the jets to reconstruct the charge of each W. The angular distributions of the W+/- and of their decay products are directly related to the helicities of the Ws, and provide an insight into the nature of the gauge boson couplings.

  19. Controlling coupled bending-twisting vibrations of anisotropic composite wing

    NASA Astrophysics Data System (ADS)

    Ryabov, Victor; Yartsev, Boris

    2018-05-01

    The paper discusses the possibility to control coupled bending-twisting vibrations of anisotropic composite wing by means of the monoclinic structures in the reinforcement of the plating. Decomposing the potential straining energy and kinetic energy of natural vibration modes into interacting and non-interacting parts, it became possible to introduce the two coefficients that integrally consider the effect of geometry and reinforcement structure upon the dynamic response parameters of the wing. The first of these coefficients describes the elastic coupling of the natural vibration modes, the second coefficient describes the inertial one. The paper describes the numerical studies showing how the orientation of considerably anisotropic CRP layers in the plating affects natural frequencies, loss factors, coefficients of elastic and inertial coupling for several lower tones of natural bending-twisting vibrations of the wing. Besides, for each vibration mode, partial values of the above mentioned dynamic response parameters were determined by means of the relationships for orthotropic structures where instead of "free" shearing modulus in the reinforcement plant, "pure" shearing modulus is used. Joint analysis of the obtained results has shown that each pair of bending-twisting vibration modes has its orientation angle ranges of the reinforcing layers where the inertial coupling caused by asymmetry of the cross-section profile with respect to the main axes of inertia decreases, down to the complete extinction, due to the generation of the elastic coupling in the plating material. These ranges are characterized by the two main features: 1) the difference in the natural frequencies of the investigated pair of bending-twisting vibration modes is the minimum and 2) natural frequencies of bending-twisting vibrations belong to a stretch restricted by corresponding partial natural frequencies of the investigated pair of vibration modes. This result is of practical importance because it enables approximate analysis of real composite wings with complex geometry in the existing commercial software packages.

  20. Analytical models for coupling reliability in identical two-magnet systems during slow reversals

    NASA Astrophysics Data System (ADS)

    Kani, Nickvash; Naeemi, Azad

    2017-12-01

    This paper follows previous works which investigated the strength of dipolar coupling in two-magnet systems. While those works focused on qualitative analyses, this manuscript elucidates reversal through dipolar coupling culminating in analytical expressions for reversal reliability in identical two-magnet systems. The dipolar field generated by a mono-domain magnetic body can be represented by a tensor containing both longitudinal and perpendicular field components; this field changes orientation and magnitude based on the magnetization of neighboring nanomagnets. While the dipolar field does reduce to its longitudinal component at short time-scales, for slow magnetization reversals, the simple longitudinal field representation greatly underestimates the scope of parameters that ensure reliable coupling. For the first time, analytical models that map the geometric and material parameters required for reliable coupling in two-magnet systems are developed. It is shown that in biaxial nanomagnets, the x ̂ and y ̂ components of the dipolar field contribute to the coupling, while all three dimensions contribute to the coupling between a pair of uniaxial magnets. Additionally, the ratio of the longitudinal and perpendicular components of the dipolar field is also very important. If the perpendicular components in the dipolar tensor are too large, the nanomagnet pair may come to rest in an undesirable meta-stable state away from the free axis. The analytical models formulated in this manuscript map the minimum and maximum parameters for reliable coupling. Using these models, it is shown that there is a very small range of material parameters which can facilitate reliable coupling between perpendicular-magnetic-anisotropy nanomagnets; hence, in-plane nanomagnets are more suitable for coupled systems.

  1. DincRNA: a comprehensive web-based bioinformatics toolkit for exploring disease associations and ncRNA function.

    PubMed

    Cheng, Liang; Hu, Yang; Sun, Jie; Zhou, Meng; Jiang, Qinghua

    2018-06-01

    DincRNA aims to provide a comprehensive web-based bioinformatics toolkit to elucidate the entangled relationships among diseases and non-coding RNAs (ncRNAs) from the perspective of disease similarity. The quantitative way to illustrate relationships of pair-wise diseases always depends on their molecular mechanisms, and structures of the directed acyclic graph of Disease Ontology (DO). Corresponding methods for calculating similarity of pair-wise diseases involve Resnik's, Lin's, Wang's, PSB and SemFunSim methods. Recently, disease similarity was validated suitable for calculating functional similarities of ncRNAs and prioritizing ncRNA-disease pairs, and it has been widely applied for predicting the ncRNA function due to the limited biological knowledge from wet lab experiments of these RNAs. For this purpose, a large number of algorithms and priori knowledge need to be integrated. e.g. 'pair-wise best, pairs-average' (PBPA) and 'pair-wise all, pairs-maximum' (PAPM) methods for calculating functional similarities of ncRNAs, and random walk with restart (RWR) method for prioritizing ncRNA-disease pairs. To facilitate the exploration of disease associations and ncRNA function, DincRNA implemented all of the above eight algorithms based on DO and disease-related genes. Currently, it provides the function to query disease similarity scores, miRNA and lncRNA functional similarity scores, and the prioritization scores of lncRNA-disease and miRNA-disease pairs. http://bio-annotation.cn:18080/DincRNAClient/. biofomeng@hotmail.com or qhjiang@hit.edu.cn. Supplementary data are available at Bioinformatics online.

  2. Evolution of separate screening soliton pairs in a biased series photorefractive crystal circuit.

    PubMed

    Liu, Jinsong; Hao, Zhonghua

    2002-06-01

    This paper presents calculations for an idea in photorefractive spatial soliton, namely, screening solitons form in a biased series photorefractive crystal circuit consisting of two photorefractive crystals connected electronically by electrode leads in a chain with a voltage source. A system of two coupled equations is derived under appropriate conditions for two-beam propagation in the crystal circuit. The possibility of obtaining steady-state bright and dark screening soliton solutions is investigated in one dimension and, the existence of dark-dark, bright-dark, and bright-bright separate screening soliton pairs in such a circuit is proved. The numerical results show that the two solitons in a soliton pair can affect each other by the light-induced current and their coupling can affect their spatial profiles, dynamical evolutions, stabilities, and self-deflection. Under the limit in which the optical wave has a spatial extent much less than the width of the crystal, only the dark soliton can affect the other soliton by the light-induced current, but the bright soliton cannot. For a bright-dark or dark-dark soliton pair, the dark soliton in a weak input intensity can be obtained for a larger nonlinearity than for a stronger input intensity. For a bright-dark soliton pair, increasing the input intensity of the dark soliton can increase the bending angle of the bright soliton. Some potential applications are discussed.

  3. Tuning the Pairing Interaction in a d -Wave Superconductor by Paramagnons Injected through Interfaces

    DOE PAGES

    Naritsuka, M.; Rosa, P. F. S.; Luo, Yongkang; ...

    2018-05-04

    Unconventional superconductivity and magnetism are intertwined on a microscopic level in a wide class of materials. A new approach to this most fundamental and hotly debated issue focuses on the role of interactions between superconducting electrons and bosonic fluctuations at the interface between adjacent layers in heterostructures. In this paper, we fabricate hybrid superlattices consisting of alternating atomic layers of the heavy-fermion superconductormore » $${\\mathrm{CeCoIn}}_{5}$$ and antiferromagnetic (AFM) metal $${\\mathrm{CeRhIn}}_{5}$$, in which the AFM order can be suppressed by applying pressure. We find that the superconducting and AFM states coexist in spatially separated layers, but their mutual coupling via the interface significantly modifies the superconducting properties. An analysis of upper critical fields reveals that, upon suppressing the AFM order by applied pressure, the force binding superconducting electron pairs acquires an extreme strong-coupling nature. Finally, this demonstrates that superconducting pairing can be tuned nontrivially by magnetic fluctuations (paramagnons) injected through the interface.« less

  4. Tuning the Pairing Interaction in a d -Wave Superconductor by Paramagnons Injected through Interfaces

    NASA Astrophysics Data System (ADS)

    Naritsuka, M.; Rosa, P. F. S.; Luo, Yongkang; Kasahara, Y.; Tokiwa, Y.; Ishii, T.; Miyake, S.; Terashima, T.; Shibauchi, T.; Ronning, F.; Thompson, J. D.; Matsuda, Y.

    2018-05-01

    Unconventional superconductivity and magnetism are intertwined on a microscopic level in a wide class of materials. A new approach to this most fundamental and hotly debated issue focuses on the role of interactions between superconducting electrons and bosonic fluctuations at the interface between adjacent layers in heterostructures. Here we fabricate hybrid superlattices consisting of alternating atomic layers of the heavy-fermion superconductor CeCoIn5 and antiferromagnetic (AFM) metal CeRhIn5 , in which the AFM order can be suppressed by applying pressure. We find that the superconducting and AFM states coexist in spatially separated layers, but their mutual coupling via the interface significantly modifies the superconducting properties. An analysis of upper critical fields reveals that, upon suppressing the AFM order by applied pressure, the force binding superconducting electron pairs acquires an extreme strong-coupling nature. This demonstrates that superconducting pairing can be tuned nontrivially by magnetic fluctuations (paramagnons) injected through the interface.

  5. Transport properties of dilute α -Fe (X ) solid solutions (X = C, N, O)

    NASA Astrophysics Data System (ADS)

    Schuler, Thomas; Nastar, Maylise

    2016-06-01

    We extend the self-consistent mean field (SCMF) method to the calculation of the Onsager matrix of Fe-based interstitial solid solutions. Both interstitial jumps and substitutional atom-vacancy exchanges are accounted for. A general procedure is introduced to split the Onsager matrix of a dilute solid solution into intrinsic cluster Onsager matrices, and extract from them flux-coupling ratios, mobilities, and association-dissociation rates for each cluster. The formalism is applied to vacancy-interstitial solute pairs in α -Fe (V X pairs, X = C, N, O), with ab initio based thermodynamic and kinetic parameters. Convergence of the cluster mobility contribution gives a controlled estimation of the cluster definition distance, taking into account both its thermodynamic and kinetic properties. Then, the flux-coupling behavior of each V X pair is discussed, and qualitative understanding is achieved from the comparison between various contributions to the Onsager matrix. Also, the effect of low-activation energy second-nearest-neighbor interstitial solute jumps around a vacancy on these results is addressed.

  6. Enhanced spin pumping into superconductors provides evidence for superconducting pure spin currents

    NASA Astrophysics Data System (ADS)

    Jeon, Kun-Rok; Ciccarelli, Chiara; Ferguson, Andrew J.; Kurebayashi, Hidekazu; Cohen, Lesley F.; Montiel, Xavier; Eschrig, Matthias; Robinson, Jason W. A.; Blamire, Mark G.

    2018-06-01

    Unlike conventional spin-singlet Cooper pairs, spin-triplet pairs can carry spin1,2. Triplet supercurrents were discovered in Josephson junctions with metallic ferromagnet spacers, where spin transport can occur only within the ferromagnet and in conjunction with a charge current. Ferromagnetic resonance injects a pure spin current from a precessing ferromagnet into adjacent non-magnetic materials3,4. For spin-singlet pairing, the ferromagnetic resonance spin pumping efficiency decreases below the critical temperature (Tc) of a coupled superconductor5,6. Here we present ferromagnetic resonance experiments in which spin sink layers with strong spin-orbit coupling are added to the superconductor. Our results show that the induced spin currents, rather than being suppressed, are substantially larger in the superconducting state compared with the normal state; although further work is required to establish the details of the spin transport process, we show that this cannot be mediated by quasiparticles and is most likely a triplet pure spin supercurrent.

  7. Holstein polaron in a valley-degenerate two-dimensional semiconductor.

    PubMed

    Kang, Mingu; Jung, Sung Won; Shin, Woo Jong; Sohn, Yeongsup; Ryu, Sae Hee; Kim, Timur K; Hoesch, Moritz; Kim, Keun Su

    2018-05-28

    Two-dimensional (2D) crystals have emerged as a class of materials with tunable carrier density 1 . Carrier doping to 2D semiconductors can be used to modulate many-body interactions 2 and to explore novel composite particles. The Holstein polaron is a small composite particle of an electron that carries a cloud of self-induced lattice deformation (or phonons) 3-5 , which has been proposed to play a key role in high-temperature superconductivity 6 and carrier mobility in devices 7 . Here we report the discovery of Holstein polarons in a surface-doped layered semiconductor, MoS 2 , in which a puzzling 2D superconducting dome with the critical temperature of 12 K was found recently 8-11 . Using a high-resolution band mapping of charge carriers, we found strong band renormalizations collectively identified as a hitherto unobserved spectral function of Holstein polarons 12-18 . The short-range nature of electron-phonon (e-ph) coupling in MoS 2 can be explained by its valley degeneracy, which enables strong intervalley coupling mediated by acoustic phonons. The coupling strength is found to increase gradually along the superconducting dome up to the intermediate regime, which suggests a bipolaronic pairing in the 2D superconductivity.

  8. Resummed tree heptagon

    NASA Astrophysics Data System (ADS)

    Belitsky, A. V.

    2018-04-01

    The form factor program for the regularized space-time S-matrix in planar maximally supersymmetric gauge theory, known as the pentagon operator product expansion, is formulated in terms of flux-tube excitations propagating on a dual two-dimensional world-sheet, whose dynamics is known exactly as a function of 't Hooft coupling. Both MHV and non-MHV amplitudes are described in a uniform, systematic fashion within this framework, with the difference between the two encoded in coupling-dependent helicity form factors expressed via Zhukowski variables. The nontrivial SU(4) tensor structure of flux-tube transitions is coupling independent and is known for any number of charged excitations from solutions of a system of Watson and Mirror equations. This description allows one to resum the infinite series of form factors and recover the space-time S-matrix exactly in kinematical variables at a given order of perturbation series. Recently, this was done for the hexagon. Presently, we successfully perform resummation for the seven-leg tree NMHV amplitude. To this end, we construct the flux-tube integrands of the fifteen independent Grassmann component of the heptagon with an infinite number of small fermion-antifermion pairs accounted for in NMHV two-channel conformal blocks.

  9. All orders results for self-crossing Wilson loops mimicking double parton scattering

    DOE PAGES

    Dixon, Lance J.; Esterlis, Ilya

    2016-07-21

    Loop-level scattering amplitudes for massless particles have singularities in regions where tree amplitudes are perfectly smooth. For example, a 2 → 4 gluon scattering process has a singularity in which each incoming gluon splits into a pair of gluons, followed by a pair of 2 → 2 collisions between the gluon pairs. This singularity mimics double parton scattering because it occurs when the transverse momentum of a pair of outgoing gluons vanishes. The singularity is logarithmic at fixed order in perturbation theory. We exploit the duality between scattering amplitudes and polygonal Wilson loops to study six-point amplitudes in this limitmore » to high loop order in planar N = 4 super-Yang-Mills theory. The singular configuration corresponds to the limit in which a hexagonal Wilson loop develops a self-crossing. The singular terms are governed by an evolution equation, in which the hexagon mixes into a pair of boxes; the mixing back is suppressed in the planar (large N c) limit. Because the kinematic dependence of the box Wilson loops is dictated by (dual) conformal invariance, the complete kinematic dependence of the singular terms for the self-crossing hexagon on the one nonsingular variable is determined to all loop orders. The complete logarithmic dependence on the singular variable can be obtained through nine loops, up to a couple of constants, using a correspondence with the multi-Regge limit. As a byproduct, we obtain a simple formula for the leading logs to all loop orders. Furthermore, we also show that, although the MHV six-gluon amplitude is singular, remarkably, the transcendental functions entering the non-MHV amplitude are finite in the same limit, at least through four loops.« less

  10. All orders results for self-crossing Wilson loops mimicking double parton scattering

    NASA Astrophysics Data System (ADS)

    Dixon, Lance J.; Esterlis, Ilya

    2016-07-01

    Loop-level scattering amplitudes for massless particles have singularities in regions where tree amplitudes are perfectly smooth. For example, a 2 → 4 gluon scattering process has a singularity in which each incoming gluon splits into a pair of gluons, followed by a pair of 2 → 2 collisions between the gluon pairs. This singularity mimics double parton scattering because it occurs when the transverse momentum of a pair of outgoing gluons vanishes. The singularity is logarithmic at fixed order in perturbation theory. We exploit the duality between scattering amplitudes and polygonal Wilson loops to study six-point amplitudes in this limit to high loop order in planar {N} = 4 super-Yang-Mills theory. The singular configuration corresponds to the limit in which a hexagonal Wilson loop develops a self-crossing. The singular terms are governed by an evolution equation, in which the hexagon mixes into a pair of boxes; the mixing back is suppressed in the planar (large N c) limit. Because the kinematic dependence of the box Wilson loops is dictated by (dual) conformal invariance, the complete kinematic dependence of the singular terms for the self-crossing hexagon on the one nonsingular variable is determined to all loop orders. The complete logarithmic dependence on the singular variable can be obtained through nine loops, up to a couple of constants, using a correspondence with the multi-Regge limit. As a byproduct, we obtain a simple formula for the leading logs to all loop orders. We also show that, although the MHV six-gluon amplitude is singular, remarkably, the transcendental functions entering the non-MHV amplitude are finite in the same limit, at least through four loops.

  11. A criterion for pure pair-ion plasmas and the role of quasineutrality in nonlinear dynamics

    NASA Astrophysics Data System (ADS)

    Saleem, H.

    2007-01-01

    A criterion is presented to decide whether a produced plasma can be called a pure pair-ion plasma or not. The theory is discussed in the light of recent experiments which claim that a pure pair-ion fullerene (C60±) plasma has been produced. It is also shown that the ion acoustic wave is replaced by the pair ion convective cell (PPCC) mode as the electron density becomes vanishingly small in a magnetized plasma comprised of positive and negative ions. The nonlinear dynamics of pure pair plasmas is described by two coupled equations which have no analog in electron-ion plasmas. In a stationary frame, it becomes similar to the Hasegawa-Mima equation but does not contain drift waves and ion acoustic waves.

  12. Effects of cooperation between translating ribosome and RNA polymerase on termination efficiency of the Rho-independent terminator.

    PubMed

    Li, Rui; Zhang, Qing; Li, Junbai; Shi, Hualin

    2016-04-07

    An experimental system was designed to measure in vivo termination efficiency (TE) of the Rho-independent terminator and position-function relations were quantified for the terminator tR2 in Escherichia coli The terminator function was almost completely repressed when tR2 was located several base pairs downstream from the gene, and TE gradually increased to maximum values with the increasing distance between the gene and terminator. This TE-distance relation reflected a stochastic coupling of the ribosome and RNA polymerase (RNAP). Terminators located in the first 100 bp of the coding region can function efficiently. However, functional repression was observed when the terminator was located in the latter part of the coding region, and the degree of repression was determined by transcriptional and translational dynamics. These results may help to elucidate mechanisms of Rho-independent termination and reveal genomic locations of terminators and functions of the sequence that precedes terminators. These observations may have important applications in synthetic biology. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

  13. Lower extremity joint coupling variability during gait in young adults with and without chronic ankle instability.

    PubMed

    Lilley, Thomas; Herb, Christopher C; Hart, Joseph; Hertel, Jay

    2018-06-01

    Chronic ankle instability (CAI) is a condition resulting from a lateral ankle sprain. Shank-rearfoot joint-coupling variability differences have been found in CAI patients; however, joint-coupling variability (VCV) of the ankle and proximal joints has not been explored. Our purpose was to analyse VCV in adults with and without CAI during gait. Four joint-coupling pairs were analysed: knee sagittal-ankle sagittal, knee sagittal-ankle frontal, hip frontal-ankle sagittal and hip frontal-ankle frontal. Twenty-seven adults participated (CAI:n = 13, Control:n = 14). Lower extremity kinematics were collected during walking (4.83 km/h) and jogging (9.66 km/h). Vector-coding was used to assess the stride-to-stride variability of four coupling pairs. During walking, CAI patients exhibited higher VCV than healthy controls for knee sagittal-ankle frontal in latter parts of stance thru mid-swing. When jogging, CAI patients demonstrated lower VCV with specific differences occurring across various intervals of gait. The increased knee sagittal-ankle frontal VCV in CAI patients during walking may indicate an adaptation to deal with the previously identified decrease in variability in transverse plane shank and frontal plane rearfoot coupling during walking; while the decreased ankle-knee and ankle-hip VCV identified in CAI patients during jogging may represent a more rigid, less adaptable sensorimotor system ambulating at a faster speed.

  14. Electrical Coupling Between Glial Cells in the Rat Retina

    PubMed Central

    Ceelen, Paul W.; Lockridge, Amber; Newman, Eric A.

    2008-01-01

    The strength of electrical coupling between retinal glial cells was quantified with simultaneous whole-cell current-clamp recordings from astrocyte–astrocyte, astrocyte–Müller cell, and Müller cell–Müller cell pairs in the acutely isolated rat retina. Experimental results were fit and space constants determined using a resistive model of the glial cell network that assumed a homogeneous two-dimensional glial syncytium. The effective space constant (the distance from the point of stimulation to where the voltage falls to 1/e) equaled 12.9, 6.2, and 3.7 µm, respectively for astrocyte–astrocyte, astrocyte–Müller cell, and Müller cell–Müller cell coupling. The addition of 1 mM Ba2+ had little effect on network space constants, while 0.5 mM octanol shortened the space constants to 4.7, 4.4, and 2.6 µm for the three types of coupling. For a given distance separating cell pairs, the strength of coupling showed considerable variability. This variability in coupling strength was reproduced accurately by a second resistive model of the glial cell network (incorporating discrete astrocytes spaced at varying distances from each other), demonstrating that the variability was an intrinsic property of the glial cell network. Coupling between glial cells in the retina may permit the intercellular spread of ions and small molecules, including messengers mediating Ca2+ wave propagation, but it is too weak to carry significant K+ spatial buffer currents. PMID:11424187

  15. A search for high-mass resonances decaying to τ + τ - in pp collisions at $$ \\sqrt{s}=8 $$ TeV with the ATLAS detector

    DOE PAGES

    Aad, G.; Abbott, B.; Abdallah, J.; ...

    2015-07-29

    A search for high-mass resonances decaying into τ⁺τ⁻ final states using proton-proton collisions at √s=8 TeV produced by the Large Hadron Collider is presented. The data were recorded with the ATLAS detector and correspond to an integrated luminosity of 19.5–20.3 fb –1. No statistically significant excess above the Standard Model expectation is observed; 95% credibility upper limits are set on the cross section times branching fraction of Z' resonances decaying into τ⁺τ⁻ pairs as a function of the resonance mass. As a result, Z' bosons of the Sequential Standard Model with masses less than 2.02 TeV are excluded at 95%more » credibility. As a result, the impact of the fermionic couplings on the Z' acceptance is investigated and limits are also placed on a Z' model that exhibits enhanced couplings to third-generation fermions.« less

  16. FCDECOMP: decomposition of metabolic networks based on flux coupling relations.

    PubMed

    Rezvan, Abolfazl; Marashi, Sayed-Amir; Eslahchi, Changiz

    2014-10-01

    A metabolic network model provides a computational framework to study the metabolism of a cell at the system level. Due to their large sizes and complexity, rational decomposition of these networks into subsystems is a strategy to obtain better insight into the metabolic functions. Additionally, decomposing metabolic networks paves the way to use computational methods that will be otherwise very slow when run on the original genome-scale network. In the present study, we propose FCDECOMP decomposition method based on flux coupling relations (FCRs) between pairs of reaction fluxes. This approach utilizes a genetic algorithm (GA) to obtain subsystems that can be analyzed in isolation, i.e. without considering the reactions of the original network in the analysis. Therefore, we propose that our method is useful for discovering biologically meaningful modules in metabolic networks. As a case study, we show that when this method is applied to the metabolic networks of barley seeds and yeast, the modules are in good agreement with the biological compartments of these networks.

  17. Demonstration of spectral correlation control in a source of polarization-entangled photon pairs at telecom wavelength.

    PubMed

    Lutz, Thomas; Kolenderski, Piotr; Jennewein, Thomas

    2014-03-15

    Spectrally correlated photon pairs can be used to improve the performance of long-range fiber-based quantum communication protocols. We present a source based on spontaneous parametric downconversion, which allows one to control spectral correlations within the entangled photon pair without spectral filtering by changing the pump-pulse duration or the characteristics of the coupled spatial modes. The spectral correlations and polarization entanglement are characterized. We find that the generated photon pairs can feature both positive spectral correlations, decorrelation, or negative correlations at the same time as polarization entanglement with a high fidelity of 0.97 (no background subtraction) with the expected Bell state.

  18. Breast Cancer and Married Couples: Research on the Couple and Treatment of the Patient.

    ERIC Educational Resources Information Center

    Carter, Ross E.; And Others

    1991-01-01

    Reviewed research on effects of breast cancer on 20 married pairs and extends results to practical aspects of doing such research and attempting treatment of breast cancer patients. Measures of individual psychological adjustment and dyadic adjustment found that both spouses appeared well adjusted and reported excellent quality of life. Interviews…

  19. Finite-size corrections in simulation of dipolar fluids

    NASA Astrophysics Data System (ADS)

    Belloni, Luc; Puibasset, Joël

    2017-12-01

    Monte Carlo simulations of dipolar fluids are performed at different numbers of particles N = 100-4000. For each size of the cubic cell, the non-spherically symmetric pair distribution function g(r,Ω) is accumulated in terms of projections gmnl(r) onto rotational invariants. The observed N dependence is in very good agreement with the theoretical predictions for the finite-size corrections of different origins: the explicit corrections due to the absence of fluctuations in the number of particles within the canonical simulation and the implicit corrections due to the coupling between the environment around a given particle and that around its images in the neighboring cells. The latter dominates in fluids of strong dipolar coupling characterized by low compressibility and high dielectric constant. The ability to clean with great precision the simulation data from these corrections combined with the use of very powerful anisotropic integral equation techniques means that exact correlation functions both in real and Fourier spaces, Kirkwood-Buff integrals, and bridge functions can be derived from box sizes as small as N ≈ 100, even with existing long-range tails. In the presence of dielectric discontinuity with the external medium surrounding the central box and its replica within the Ewald treatment of the Coulombic interactions, the 1/N dependence of the gmnl(r) is shown to disagree with the, yet well-accepted, prediction of the literature.

  20. Neural network integration during the perception of in-group and out-group members.

    PubMed

    Greven, Inez M; Ramsey, Richard

    2017-11-01

    Group biases guide social interactions by promoting in-group favouritism, but the neural mechanisms underpinning group biases remain unclear. While neuroscience research has shown that distributed brain circuits are associated with seeing in-group and out-group members as "us" and "them", it is less clear how these networks exchange signals. This fMRI study uses functional connectivity analyses to investigate the contribution of functional integration to group bias modulation of person perception. Participants were assigned to an arbitrary group and during scanning they observed bodies of in-group or out-group members that cued the recall of positive or negative social knowledge. The results showed that functional coupling between perceptual and cognitive neural networks is tuned to particular combinations of group membership and social knowledge valence. Specifically, coupling between body perception and theory-of-mind networks is biased towards seeing a person that had previously been paired with information consistent with group bias (positive for in-group and negative for out-group). This demonstrates how brain regions associated with visual analysis of others and belief reasoning exchange and integrate signals when evaluating in-group and out-group members. The results update models of person perception by showing how and when interplay occurs between perceptual and extended systems when developing a representation of another person. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

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