Sample records for symmetric top molecules

  1. Photofragment angular momentum polarization in the photolysis of symmetric top molecules: Production, detection, and rotational depolarization

    E-print Network

    Photofragment angular momentum polarization in the photolysis of symmetric top molecules: Photodissociation Symmetric top molecule Photofragment Angular momentum Polarization a b s t r a c t We present the fully quantum mechanical distribution of the photofragment angular momentum polar- ization

  2. Rovibrational Interaction and Vibrational Constants of the Symmetric Top Molecule 14NF3

    PubMed Central

    2013-01-01

    Several accurate experimental values of the ?C and ?B rotation-vibration interaction parameters and ?i, xij, and gij vibrational constants have been extracted from the most recent high-resolution Fourier transform infrared, millimeter wave, and centimeter wave investigations in the spectra of the oblate symmetric top molecule 14NF3. The band-centres used are those of the four fundamental, the overtones, the combination, and hot bands identified in the region between 400?cm?1 and 2000?cm?1. Comparison of our constants with the ones measured previously, by infrared spectroscopy at low resolution, reveals orders of magnitude higher accuracy of the new values. The agreement between our values and those determined by ab initio calculations employing the TZ2Pf basis is excellent. PMID:23766711

  3. Rotational excitation of symmetric top molecules by collisions with atoms. II - Infinite order sudden approximation

    NASA Technical Reports Server (NTRS)

    Green, S.

    1979-01-01

    The infinite order sudden (IOS) approximation is extended to rotational excitation of symmetric tops by collisions with atoms. After development of a formalism for 'primitive' or 'one-ended' tops, proper parity-adapted linear combinations describing real rotors are considered and modifications needed for asymmetric rigid rotors are noted. The generalized spectroscopic relaxation cross sections are discussed. IOS calculations for NH3-He and H2CO-He are performed and compared with more accurate calculations, and the IOS approximation is found to provide a reasonably accurate description.

  4. Methyl cyanide hot and warm cores in Orion: Statistical equilibrium excitation models of a symmetric-top molecule

    SciTech Connect

    Loren, R.B.; Mundy, L.G.

    1984-11-01

    More than 50 lines of the symmetric-top molecule CH/sub 3/CN, from J = 6--5 up to J = 16--15 and components from K = 0 to K = 7, have been observed toward OMC-1. High-velocity resolution line profiles reveal two kinematically and thermally distinct regions; broad emission (..delta..Vapprox.12 km s/sup -1/) at 5.1 km s/sup -1/ arising from an unresolved hot core and narrow emission (..delta..Vapprox.4 km s/sup -1/) at 8.7 km s/sup -1/ arising from dense warm clumps of the quiescent cloud. Statistical equilibrium models fitted to the resolved K = 3 and K = 6 A species line profiles yield kinetic temperatures for the regions emitting the broad and narrow components of 275 +- 25 K and 95 +- 8 K, respectively. The CH/sub 3/CN abundance is enhanced in the hot core by a factor of at least 10 relative to the quiescent cloud. The excitation of the statistical equilibrium (SE) models is compared to that predicted by the rotational temperature equilibrium (RTE) analytic method. The RTE method can accurately predict T/sub k/ for both of the nearly thermalized regions in OMC-1 when T/sub rot/ is determined from levels which span a large range of J, but not with Hollis's 1982 method of determining T/sub rot/ from adjacent J levels. For high-temperature CH/sub 3/CN regions the RTE method fails to correctly predict T/sub k/ in the density range from 10/sup 2.5/ cm/sup -3/ to 10/sup 6/ cm/sup -3/ which commonly occurs in molecular clouds.

  5. Forbidden vibrational-rotational transitions and Herman-Wallis factors in fundamental IR bands of symmetric-top molecules

    NASA Astrophysics Data System (ADS)

    Mikhailov, V. M.

    2010-05-01

    Within the theory of coupled schemes of ordering of vibrational-rotational interactions, the operator of the effective dipole moment of single-quantum vibrational transitions is represented in the form of an infinite series in vibrational (normal coordinates and conjugate momenta) or rotational variables (components of the total angular momentum). Mechanisms of activation of infrared-inactive totally symmetric vibrations in molecules of the D 2 a , D 3 h , C 3 h , D n ( n ? 3), S 4, T, T a , and O symmetries and forbidden vibrational-rotational transitions in IR bands of active vibrations have been studied. The group-theoretic analysis of tensor parameters in higher-order effective dipole moments of single-quantum vibrational transitions in axially symmetric molecules has been performed. The strengths of allowed transitions and forbidden transitions in fundamental and hot IR bands of axially symmetric molecules are calculated with allowance for the Herman-Wallis factors. For effective dipole moments of multiquantum transitions in molecules, models are developed in the form of infinite series in rotational variables and in the form of Padé approximants.

  6. Rotational Spectra of Symmetric Top Molecules in Ground and Different Vibrational Excited States, and Phenomenon of Resonance – Applying in CF3CCH

    PubMed Central

    Motamedi, Masoud

    2007-01-01

    This paper deals with review of exploration of resonance in symmetric top molecules in different vibrational excited states, vt = n (n =1, 2, 3, 4). Calculations for CF3CCH shows that resonance take place at k=x??+(A-B)-2A?A?-(A-B) and k=x??+(A-B)-2A?A?-(A-B) for v10 = 2 and v10 = 3 respectively. In order to account for splitting about 3 MHz for the ? 2 series in v10 = 4 is necessary to introduce the element ? J,k, ?|f24| J,k + 2, ? ? 4? in fitting program.

  7. Effects of collisional interference of lines in the spectra of symmetric top molecules: II. Self- and foreign-gas-broadening of rotational spectral lines

    NASA Astrophysics Data System (ADS)

    Cherkasov, M. R.

    2009-01-01

    The theory outlined in the first part of the study is applied to an analysis of self-broadening and broadening by foreign gases of spectral lines for a number of symmetric top molecules with a high potential barrier to the inversion vibration. In all cases considered, the results obtained are in better agreement with the experimental data than previous theoretical results; however, in some cases, the discrepancy is rather large. Possible reasons are discussed and the acute need for experimental data obtained with modern equipment is noted.

  8. On the Determination of C0 (or A0), D0K, H0K, and Some Dark States for Symmetric-top Molecules from Infrared Spectra without the Need for Localized Perturbations

    SciTech Connect

    Maki, Arthur; Masiello, Tony; Blake, Thomas A.; Nibler, Joseph W.; Weber, Alfons

    2009-05-01

    For symmetric top molecules, the normal ?k = 0, ?l = 0 and ?k = ?1, ?l = ?1 selection rules for parallel and perpendicular bands, respectively, do not allow the determination of the K-dependent rotational constants, C0 (or A0), D0K, and H0K. However, we show here that several different combinations of allowed and apparently unperturbed rovibrational infrared transitions can give access to those constants. A necessary ingredient for the application of this technique is a band with selection rules ?k = ?1 (or ?k = 0), ?l = ?2, such as an overtone or difference band, and appropriate other bands. Bands with selection rules ?k = ?2, ?l = ?1 are also useful but are seldom found. As a general rule, more than one vibrational transition is needed. Examples are given for boron trifluoride (BF3), sulfur trioxide (SO3), and cyclopropane (C3H6) for which there are microwave measurements that provide a check on the derived constants. The technique is also extended to a D2d molecule, allene, even though we have no measurements to use as an example. Examples are also given for the determination of dark states from difference bands, and/or hot bands, and also whole forbidden bands that arise from mixing with distant energy levels.

  9. Phase behavior of symmetric disk-coil molecules

    E-print Network

    Kim, Yongjoo

    We investigate the self-assembly of symmetric disk-coil molecules using Monte Carlo simulations in the NPT ensemble. Our molecules are composed of a planar disk (head) that is covalently bonded to a single coil (tail), and ...

  10. Nuclear magnetic spin-rotational relaxation times for symmetric molecules

    Microsoft Academic Search

    James McConnell

    1982-01-01

    It is shown that the problem of calculating times related to nuclear magnetic spin-rotational interactions may be solved for the symmetric rotator model of a molecule by employing the method already proposed in a general manner for asymmetric molecules that undergo rotational thermal motion. Expressions are derived for the spin-rotational correlation time and for the contributions arising from spin-rotational interactions

  11. Resonances in the heavy symmetrical top with vibrating pivot

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, S.

    2013-02-01

    In this work we consider a heavy symmetrical top whose pivot is subjected to small-amplitude, high-frequency vibrations in the vertical direction. For analytical simplicity we confine ourselves to positions of the top close to the vertical. We first apply the slow-fast separation method originally devised by Kapitza and Landau for analysing the vibrational stabilization of an inverted pendulum. This analysis yields the slow precession frequency but we see that the equations become undefined at a particular value of the vibration frequency. This breakdown is seen to correspond to a resonance and we use Euler's equations to write down the solution at the resonance. For vibration in the horizontal direction there is a resonance at more or less the same frequency as before but the dynamics at the resonance is different from the former case.

  12. Rotational relaxation of spherical-top molecules by atoms

    Microsoft Academic Search

    J. T. Bartis

    1976-01-01

    A theoretical study of rotational relaxation of spherical-top molecules in an inert gas is presented. Under the assumption that the molecules and atoms collide as rough spheres, two previous theoretical methods obtained apparently conflicting results. These two methods are shown to be in agreement, the discrepancy being related to the definition of a fundamental relaxation time. When applied to the

  13. Hamiltonian dynamics of a symmetric top in external fields having axial symmetry. Levitating Orbitron

    E-print Network

    Stanislav S. Zub; Sergiy I. Zub

    2015-02-13

    The symmetric top is a special case of the general top, and canonical Poisson structure on $T^*SE(3)$ is the common method of its description. This structure is invariant under the right action of $SO(3)$, but the Hamiltonian of the symmetric top is invariant only under the right action of subgroup $S^1$ that corresponds to the rotation around the symmetry axis of the symmetric top. So, its Poisson structure was obtained as the reduction $T^*SE(3)/S^1$. Next we propose the Hamiltonian that describes the wide class of the interaction models of symmetric top and axially-symmetric external field. The stability of the levitating Orbitron in relative equilibrium was proved.

  14. Systematic studies of molecular vibrational anharmonicity and vibration-rotation interaction by self-consistent-field higher derivative methods: Applications to asymmetric and symmetric top and linear polyatomic molecules

    SciTech Connect

    Clabo, D.A. Jr.

    1987-04-01

    Inclusion of the anharmonicity normal mode vibrations (i.e., the third and fourth (and higher) derivatives of a molecular Born-Oppenheimer potential energy surface) is necessary in order to theoretically reproduce experimental fundamental vibrational frequencies of a molecule. Although ab initio determinations of harmonic vibrational frequencies may give errors of only a few percent by the inclusion of electron correlation within a large basis set for small molecules, in general, molecular fundamental vibrational frequencies are more often available from high resolution vibration-rotation spectra. Recently developed analytic third derivatives methods for self-consistent-field (SCF) wavefunctions have made it possible to examine with previously unavailable accuracy and computational efficiency the anharmonic force fields of small molecules.

  15. Modulated structures in nematic monolayers formed by symmetric molecules.

    PubMed

    Lelidis, I; Barbero, G

    2005-02-01

    An analysis based on symmetry yields a general form for the deformation elastic energy of a nematic monolayer, formed by achiral symmetric molecules, deposited on a solid substrate. Lifshitz-invariant-like terms in the energy, which originate from the substrate field, can induce a modulated-tilt state if the anchoring energy is sufficiently low. A way to enhance the symmetry breaking is to apply a destabilizing magnetic or electric field that serves to lower the anchoring energy. In the case of an initial state with homeotropic alignment, the phase diagram displays a cusp-shaped tilt-modulated state intervening between two uniform tilt states. PMID:15783361

  16. Molecular collisions. 11: Semiclassical approximation to atom-symmetric top rotational excitation

    NASA Technical Reports Server (NTRS)

    Russell, D.; Curtiss, C. F.

    1973-01-01

    In a paper of this series a distorted wave approximation to the T matrix for atom-symmetric top scattering was developed which is correct to first order in the part of the interaction potential responsible for transitions in the component of rotational angular momentum along the symmetry axis of the top. A semiclassical expression for this T matrix is derived by assuming large values of orbital and rotational angular momentum quantum numbers.

  17. Molecular collisions 21: Semiclassical approximation to atom-symmetric top rotational excitation

    NASA Technical Reports Server (NTRS)

    Russell, D.; Curtiss, C. F.

    1973-01-01

    A distorted wave approximation to the T matrix for atom-symmetric top scattering was developed. The approximation is correct to first order in the part of the interaction potential responsible for transitions in the component of rotational angular momentum along the symmetry axis of the top. A semiclassical expression for this T matrix is derived by assuming large values of orbital and rotational angular momentum quantum numbers.

  18. Langmuir Fiilms of Anthracene Derivatives on Liquid Mercury I: Symmetric Molecules

    SciTech Connect

    Tamam,L.; Kraack, H.; Sloutskin, E.; Ocko, B.; Pershan, P.; Ofer, E.; Deutsch, M.

    2007-01-01

    The structure and phase sequence of liquid-mercury-supported Langmuir films (LFs) of two symmetric acenes, anthracene and anthraquinone, were studied by surface tensiometry and X-ray diffraction. At low coverage, both form a monolayer of surface-parallel, flat-lying, molecules. At high coverage, we find a monolayer of side-lying molecules, where the molecular plane is surface-normal, and the molecular long axis is surface-parallel. None of these phases exhibit long-range in-plane order.

  19. Competitive self-assembly of symmetrical, difunctional molecules on ambient copper surfaces.

    PubMed

    Pranger, Lawrence; Goldstein, Alex; Tannenbaum, Rina

    2005-06-01

    This paper describes competitive self-assembly from solutions of symmetric alpha,omega-difunctional molecules on Cu substrates briefly exposed (less than 5 min) to ambient conditions. XPS and PM-IRRAS were utilized as complimentary surface analytical techniques to characterize the resulting organized organic thin films (OOTFs) on these "ambient" Cu surfaces. The order of preferential adsorption was observed to be diisocyanide approximately = dithiol > dicarboxylic acid > dinitrile > diisothiocyanate, indicating that the isocyanide (-NC), and thiol (-SH) functions provide the strongest adhesion to ambient Cu. 1,4-Phenylene diisocyanide and 1,4-terephthalic acid were both observed to adopt a standing-up phase configuration, in which the difunctional molecules bond to the base substrate through only one terminal functional group, with the other terminal group disposed away from the substrate. This indicates the ability to utilize OOTFs to produce "sticky surfaces" on ambient Cu. All other molecules bonded to the substrate through both terminal groups, in either surface-parallel or arched "hairpin" configurations. On the basis of these findings, aromatic diisocyanides and diacids are the most suitable molecules for creating OOTFs with high packing density. Such films can be utilized as protective coatings in the assembly of printed circuit boards, where Cu is becoming an increasingly important substrate for interconnects. Moreover, the ability to create chemically sticky surfaces on ambient Cu substrates indicates exciting potential for the development of a new surface-mount technology operative at the nanometer scale. PMID:15924468

  20. Anomalous absorption in a-type asymmetric top molecules in cosmic objects

    NASA Astrophysics Data System (ADS)

    Chandra, Suresh

    Since the detection of the first molecule OH in cosmic objects in 1963, scientists got interested in identification of molecules in the cosmic objects. By now more than 170 molecules have been identified. In order to know about the physical conditions prevailing in the cool cosmic objects and about the chemical reactions going on there, scientists are interested in identification of as many molecules as possible. In some molecular clouds, the kinetic temperature is very low, 10 - 20 K. For such objects, anomalous absorption, i.e., the absorption against the cosmic microwave background, may play an important role for identification of molecules. The transition 111 - 110 at 4.829 GHz of H_2CO was the first one showing the anomalous absorption in the cosmic objects. The molecule H_2CS also has been identified in the cosmic objects. We have discussed about the anomalous absorption of 111 - 110 transition in a-type asymmetric top molecules. For the investigation, the required parameters are the radiative and collisional transition probabilities. We can calculate radiative transition probabilities between the rotational levels. Calculation of collisional rates is a tedious job. In absence of accurate collisional rates, we can investigated the anomalous absorption in a qualitative manner by using the scaled values for collisional rates. We find that anomalous absorption of 111 - 110 transition is possible, provided collisional rates satisfy the required condition.

  1. Stark-Zeeman Effects on Asymmetric Top Molecules. Formaldehyde H2CO

    Microsoft Academic Search

    Kunitaka Kondo; Takeshi Oka

    1960-01-01

    The combined Stark-Zeeman effects for asymmetric top molecules with no accidental degeneracies are studied by perturbation treatments. The theory was applied successfully to the analysis of the experimental results of Stark-Zeeman effect on the microwave spectrum of formaldehyde H2CO. By the influence of the electric field perpendicular to the magnetic field, split components of the transition 211--> 212 which, in

  2. Collision-induced absorption in mixtures of symmetrical linear and tetrahedral molecules - Methane-nitrogen

    NASA Technical Reports Server (NTRS)

    Birnbaum, G.; Borysow, A.; Buechele, A.

    1993-01-01

    The far infrared absorption of a CH4-N2 mixture was measured at 297, 195, and 162 K from 30 to 650/cm. The spectral invariants gamma1 and alpha1, proportional, respectively, to the zeroth and first spectral moments, due to bimolecular collisions between CH4 and N2 were obtained from these data and compared with theoretical values. The theory for collision-induced dipoles between a tetrahedral and a diatomic or symmetrical linear molecule includes contributions not previously considered. Whereas the theoretical values of gamma1 are only somewhat greater than experiment at all temperatures, the theoretical values of alpha1 are significantly lower than the experimental values. From the theoretical spectral moments for the various induced dipole components, the parameters of the BC shape were computed, and theoretical spectra were constructed. Good agreement was obtained at the lower frequencies, but with increasing frequencies the theoretical spectra were increasingly less intense than the experimental spectra. Although the accuracy of the theoretical results may suffer from the lack of a reliable potential function, it does not appear that this high frequency discrepancy can be removed by any conceivable modification in the potential.

  3. Extension of the Measurement, Assignment, and Fit in the Ground State of the Two-Top Molecule Methyl Acetate

    NASA Astrophysics Data System (ADS)

    Nguyen, H. V. L.; Kleiner, I.; Shipman, S.; Kobayashi, K.

    2013-06-01

    New spectroscopic data were recorded for the two-top molecule methyl acetate with a chirped-pulse Fourier transform microwave spectrometer at room temperature and a jet cooled sub-millimeterwave spectrometer. More than 650 new lines with J up to 35 and K up to 15 were assigned. In total, approximately 1500 lines were fitted with 34 parameters using the program BELGI-C_s-2tops to a standard deviation close to the measurement error. More precise determinations of the top-top interaction and the J, K dependent parameters as well as the influence of the total rotation on the top-top interaction were carried out. The extension of the ground state spectrum of methyl acetate is a necessary step before searching for the first torsional excited transition in both torsional modes in the room temperature spectrum.

  4. Top

    Microsoft Academic Search

    Mo Chen; Zixi Jia; Yu Gu; Ge Yu

    2011-01-01

    \\u000a An important topic in the field of spatial data management is processing the queries involving uncertain locations. This paper\\u000a focuses on the problem of finding probabilistic K closest pairs between two uncertain spatial datasets, namely, Top-K probabilistic closest pairs (TopK-PCP) query, which has popular usages in real applications. Specifically, given two uncertain datasets in which each spatial\\u000a object is modeled

  5. "Majority-rules" operative in chiral columnar stacks of C3-symmetrical molecules.

    PubMed

    van Gestel, Jeroen; Palmans, Anja R A; Titulaer, Bram; Vekemans, Jef A J M; Meijer, E W

    2005-04-20

    C(3)-symmetrical disks 1, preorganized by acylated 2,2'-bipyridine-3,3'-diamine moieties and decorated with nine identical chiral, lipophilic tails, aggregate into a dynamic helix in apolar solvents. The aggregates, previously shown to be governed by the "sergeants-and-soldiers" principle when mixed with achiral analogues, are now also revealed to obey the "majority-rules" effect, a phenomenon not earlier observed in nonpolymers. Our experimental circular dichroism data can be accurately described with a recently developed theory. A fit of the theory to the experimental results shows that the mismatch penalty, i.e., the free energy of a monomer present in a helix of its nonpreferred screw sense (0.94 kJ/mol), is about 8 times lower than the penalty for a helix reversal (7.8 kJ/mol). This corresponds well to our vision of the supramolecular architecture of the disks. PMID:15826186

  6. Adsorption-induced chirality in highly symmetric hydrocarbon molecules: lattice matching to substrates of lower symmetry

    NASA Astrophysics Data System (ADS)

    Richardson, Neville V.

    2007-10-01

    For molecules of high symmetry and lateral interactions dominated by van der Waals' interactions, such as some planar aromatic hydrocarbons, there is a preference for hexagonal close packing on adsorption. Optimization of packing by minimization of the interadsorbate spacing may favour correlated rotations of the molecules, which reduces the symmetry and leads to chiral properties in the two-dimensional overlayer. Independently, mapping of the preferred hexagonal packing on to lower symmetry substrates, which provide pseudo-hexagonal lattices, can lead to alternative mirror image lattices. The interaction of these independent chiral phenomena gives rise to diastereoisomerism in the adsorbed array. Coronene and its substituted, larger derivative hexa-tert-butyl hexabenzocoronene adsorbed on copper surfaces provide examples of these phenomena. A new structure is proposed for coronene on Cu{100} while new STM and LEED data are presented for this molecule adsorbed on Cu{110}. Finally, the adsorption of hexa-tert-butyl hexabenzocoronene on Cu{110} is re-examined and the implications of the competition between two, closely related, pseudo-hexagonal lattices are considered.

  7. Ionization of one- and three-dimensionally-oriented asymmetric-top molecules by intense circularly polarized femtosecond laser pulses

    SciTech Connect

    Hansen, Jonas L. [Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C (Denmark); Holmegaard, Lotte; Kalhoej, Line; Kragh, Sofie Louise [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Stapelfeldt, Henrik [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C (Denmark); Filsinger, Frank; Meijer, Gerard; Kuepper, Jochen; Dimitrovski, Darko; Abu-samha, Mahmoud; Martiny, Christian Per Juul; Madsen, Lars Bojer [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Germany); Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

    2011-02-15

    We present a combined experimental and theoretical study on strong-field ionization of a three-dimensionally-oriented asymmetric top molecule, benzonitrile (C{sub 7}H{sub 5}N), by circularly polarized, nonresonant femtosecond laser pulses. Prior to the interaction with the strong field, the molecules are quantum-state selected using a deflector and three-dimensionally (3D) aligned and oriented adiabatically using an elliptically polarized laser pulse in combination with a static electric field. A characteristic splitting in the molecular frame photoelectron momentum distribution reveals the position of the nodal planes of the molecular orbitals from which ionization occurs. The experimental results are supported by a theoretical tunneling model that includes and quantifies the splitting in the momentum distribution. The focus of the present article is to understand strong-field ionization from 3D-oriented asymmetric top molecules, in particular the suppression of electron emission in nodal planes of molecular orbitals. In the preceding article [Dimitrovski et al., Phys. Rev. A 83, 023405 (2011)] the focus is to understand the strong-field ionization of one-dimensionally-oriented polar molecules, in particular asymmetries in the emission direction of the photoelectrons.

  8. Abnormal difference between the mobilities of left- and right-twisted conformations of C6H12N2 roto-symmetrical molecules at very low temperatures.

    PubMed

    Gabuda, S P; Kozlova, S G

    2015-06-21

    We report an abnormal difference of low-temperature mobility of left-twisted and right-twisted conformations of roto symmetric molecules C6H12N2 (dabco) located in the same positions in crystal Zn2(C8H4O4)2?C6H12N2. The difference between (1)H NMR (Nuclear Magnetic Resonance) spin-relaxation data for left-twisted and right-twisted molecules reaches ?3 × 10(3) times at 8 K and tends to grow at lower temperatures. We argue that taking into account four-component relativistic Dirac wave functions in the vicinity of the nodal plane of dabco molecules and vacuum fluctuations due to virtual particle-antiparticle pairs can explain the changes which C6H12N2 conformations undergo at low temperatures. PMID:26093554

  9. Abnormal difference between the mobilities of left- and right-twisted conformations of C6H12N2 roto-symmetrical molecules at very low temperatures

    NASA Astrophysics Data System (ADS)

    Gabuda, S. P.; Kozlova, S. G.

    2015-06-01

    We report an abnormal difference of low-temperature mobility of left-twisted and right-twisted conformations of roto symmetric molecules C6H12N2 (dabco) located in the same positions in crystal Zn2(C8H4O4)2?C6H12N2. The difference between 1H NMR (Nuclear Magnetic Resonance) spin-relaxation data for left-twisted and right-twisted molecules reaches ˜3 × 103 times at 8 K and tends to grow at lower temperatures. We argue that taking into account four-component relativistic Dirac wave functions in the vicinity of the nodal plane of dabco molecules and vacuum fluctuations due to virtual particle-antiparticle pairs can explain the changes which C6H12N2 conformations undergo at low temperatures.

  10. Chaos in a semiclassical model of multiphoton excitation of spherical top molecules

    SciTech Connect

    Galbraith, H.W.; Ackerhalt, J.R.; Milonni, P.W.

    1983-01-01

    We study the dynamical effects of vibration-rotation coupling in multiple photon excitation at lowest order. Our molecular model is the simplest possible: that of an oscillator (triply degenerate) and uncoupled rigid rotor. The molecule-field interactions introduce a vibration-rotation nonlinearity which gives rise to nonconservation of the molecular angular momentum and in some instances consequent chaotic dynamics. The chaos leads to incoherence (widely seen in experiments) in the time dependence of the photon absorption and is not treatable in an additive way as inhomogeneous broadening. The nonconservation of the molecular angular momentum is due to the development with time of the molecular vibrational angular momentum. The degree of chaotic behavior is found to depend upon the relative size of the vibrational to pure rotational angular momenta as the excitation progresses, i.e., when vibrational angular momentum exceeds the pure rotational angular momentum we find chaos, conversely when J/sub 0/ is quite large the motion is gyroscopically stabilized and quasiperiodic. Therefore the suggested cold experiments are perhaps not so desirable.

  11. A new graphical version of STROTAB: The analysis and fitting of singlet triplet spectra of asymmetric top molecules in the prolate or oblate limits

    NASA Astrophysics Data System (ADS)

    Kodet, John; Judge, Richard H.

    2007-05-01

    The original version of STROTAB has been modified to run under Microsoft Windows using the C++ programming language. The new version takes full advantage of the Microsoft Foundation Classes available within the Microsoft Visual C++ Version 6 development environment. Specifically, windows can be created that edit the input file, summarize the results of the least-squares fit, display the calculated and observed spectra, display whole or partial sections of the calculated spectra as a stick or Gaussian de-convoluted spectrum. A listing of the rotational quantum numbers in the cases (a) and (b) limits for each of the displayed lines is provided. A branch annotating routine provides a quick visual guide to the assignment of the spectrum. A new eigenvalue sorting method has been added as an option that complements the existing method based on the eigenvector coefficients. The new sorting method has eliminated some difficulties that may arise using the existing "Least Ambiguous Method". The program has been extended to handle near-oblate asymmetric tops using a type III r representation. New version summaryTitle of program: STROTAB Version number: 2 Catalogue identifier:ADCA_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADCA_v2_0 Program obtainable from:CPC Program Library, Queen's University of Belfast, N. Ireland Reference in CPC to previous version: 93 (1996) 241-264 Catalog identifier of previous version: ADCA Authors of previous version: R.H. Judge, E.D. Womeldorf, R.A. Morris, D.E. Shimp, D.J. Clouthier, D.L. Joo, D.C. Moule Does the new version supersede the original program: Yes Computers for which the program is designed and others on which it has been tested: Pentium Xenon, Pentium Pro and Later Operating systems or monitors under which program has been tested: Windows 98, Windows 2000, Windows XP Programming language used in the new version: ANSI C, C++, Microsoft Foundation Class (MFC) No. of lines in distributed program, including test data, etc.:11 913 No. of bytes in distributed program, including test data, etc.: 2 816 652 Memory required to execute with typical data: 7 Meg No of bits in a word: 16 No of processors used: 1 Has the code been vectorized or parallelized?: No No. of bytes in distributed program, including test data, etc.: ˜3.2 MB (compressed) Distribution format: zip file Additional keywords:near oblate top, bootstrap eigenvalue sorting, graphical environment, band contour Nature of physical problem: The least-squares/band contour fitting of the singlet-triplet spectra of asymmetric tops of orthorhombic symmetry using a basis set appropriate to the symmetric top limit (prolate or oblate) of the molecule in either Hund's case (a) or case (b) coupling situations. Method of solution: The calculation of the eigenvectors and eigenvalues remains unchanged from the earlier version. An option to sort the eigenvalues of the current J by fitting them to regular progressions formed from earlier J values (bootstrap method) can be used as an option in place of the existing method based on eigenvector coefficients. Reasons for the new version: The earlier version can only handle oblate tops by diagonalizing using the prolate limit. This has turned out to be unacceptable. An improved method of sorting eigenvalues under certain conditions is also needed. A graphical interface has been added to ease the use of the program. Summary of revisions: The Hamiltonian can now be constructed in a limit appropriate the representation for of the molecule. Sorting by an alternate method is now offered. Numerous graphical features have been added. Restrictions on complexity of the problem: The rotational quantum number restrictions are J?255 and K (or P) ?127. The allowed transition frequency minus the band origin frequency must be in the range of ±10 000 cm -1. Up to five decimal places may be reported. The number of observed lines is limited by the dynamic memory and the amount of disk space available. Only molecules of symmetry D 2h, D 2 and C 2v can be accommodated in this version. Only constant

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

    PubMed

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

    2014-06-28

    The refinement of the Robert-Bonamy formalism by considering the line coupling for linear molecules developed in our previous studies [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013); 140, 104304 (2014)] have been extended to asymmetric-top molecules. For H2O immersed in N2 bath, the line coupling selection rules applicable for the pure rotational band to determine whether two specified lines are coupled or not are established. Meanwhile, because the coupling strengths are determined by relative importance of off-diagonal matrix elements versus diagonal elements of the operator -iS1 - S2, quantitative tools are developed with which one is able to remove weakly coupled lines from consideration. By applying these tools, we have found that within reasonable tolerances, most of the H2O lines in the pure rotational band are not coupled. This reflects the fact that differences of energy levels of the H2O states are pretty large. But, there are several dozen strongly coupled lines and they can be categorized into different groups such that the line couplings occur only within the same groups. In practice, to identify those strongly coupled lines and to confine them into sub-linespaces are crucial steps in considering the line coupling. We have calculated half-widths and shifts for some groups, including the line coupling. Based on these calculations, one can conclude that for most of the H2O lines, it is unnecessary to consider the line coupling. However, for several dozens of lines, effects on the calculated half-widths from the line coupling are small, but remain noticeable and reductions of calculated half-widths due to including the line coupling could reach to 5%. Meanwhile, effects on the calculated shifts are very significant and variations of calculated shifts could be as large as 25%. PMID:24985632

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

    NASA Astrophysics Data System (ADS)

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

    2014-06-01

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

  14. Analysis of electron diffraction data for several symmetric coordinates of large-amplitude motions in the case of the 1,3,5-trinitrobenzene molecule

    NASA Astrophysics Data System (ADS)

    Khaikin, L. S.; Kochikov, I. V.; Tikhonov, D. S.; Grikina, O. E.

    2015-06-01

    A brief description of a solution of the problem on electron diffraction analysis using the potential procedure for nonrigid molecules with large-amplitude motions along several symmetric internal coordinates was given. The efficiency of the approach was demonstrated for determination of the equilibrium geometry of the 1,3,5-trinitrobenzene molecule with three equivalent internal rotation coordinates of NO2 groups. The results of the electron diffraction experiment and quantum-chemical calculation at the MP2( full)/ cc-pVTZ level were considered along with the vibrational spectra of 1,3,5-trinitrobenzene and a planar equilibrium D 3 h symmetry conformation for the molecule was found reliably for the first time. The geometrical parameters of the molecule were determined ( r e , the bond lengths are given in Å, the angles in deg): CC 1.387(2), CN 1.474(4), NO 1.220(1), CH 1.072(31), ONO 125.8(2), CC(H)C 116.6(3), HCC* 121.7(1), CC(N)C* 123.4(3), NCC* 118.3(1), and CNO* 117.1(1); the asterisk marks the dependent parameters.

  15. Using fixed-node diffusion Monte Carlo to investigate the effects of rotation-vibration coupling in highly fluxional asymmetric top molecules: Application to H2D+

    NASA Astrophysics Data System (ADS)

    Petit, Andrew S.; Wellen, Bethany A.; McCoy, Anne B.

    2013-01-01

    A fixed-node diffusion Monte Carlo approach for obtaining the energies and wave functions of the rotationally excited states of asymmetric top molecules that undergo large amplitude, zero-point vibrational motions is reported. The nodal surfaces required to introduce rotational excitation into the diffusion Monte Carlo calculations are obtained from the roots of the asymmetric top rigid rotor wave functions calculated using the system's zero-point, vibrationally averaged rotational constants. Using H2D+ as a model system, the overall accuracy of the methodology is tested by comparing to the results of converged variational calculations. The ability of the fixed-node diffusion Monte Carlo approach to provide insights into the nature and strength of the rotation-vibration coupling present in the rotationally excited states of highly fluxional asymmetric tops is discussed. Finally, the sensitivity of the methodology to the details of its implementation, such as the choice of embedding scheme, is explored.

  16. A spray-coating process for highly conductive silver nanowire networks as the transparent top-electrode for small molecule organic photovoltaics.

    PubMed

    Selzer, Franz; Weiss, Nelli; Kneppe, David; Bormann, Ludwig; Sachse, Christoph; Gaponik, Nikolai; Eychmüller, Alexander; Leo, Karl; Müller-Meskamp, Lars

    2015-02-14

    We present a novel top-electrode spray-coating process for the solution-based deposition of silver nanowires (AgNWs) onto vacuum-processed small molecule organic electronic solar cells. The process is compatible with organic light emitting diodes (OLEDs) and organic light emitting thin film transistors (OLETs) as well. By modifying commonly synthesized AgNWs with a perfluorinated methacrylate, we are able to disperse these wires in a highly fluorinated solvent. This solvent does not dissolve most organic materials, enabling a top spray-coating process for sensitive small molecule and polymer-based devices. The optimized preparation of the novel AgNW dispersion and spray-coating at only 30 °C leads to high performance electrodes directly after the deposition, exhibiting a sheet resistance of 10.0 ? ?(-1) at 87.4% transparency (80.0% with substrate). By spraying our novel AgNW dispersion in air onto the vacuum-processed organic p-i-n type solar cells, we obtain working solar cells with a power conversion efficiency (PCE) of 1.23%, compared to the air exposed reference devices employing thermally evaporated thin metal layers as the top-electrode. PMID:25584968

  17. Enhanced ionization of the non-symmetric HeH{sup +} molecule driven by intense ultrashort laser pulses

    SciTech Connect

    Dehghanian, E. [Department of Chemistry, University of Sistan and Baluchestan, Zahedan 98155-987 (Iran, Islamic Republic of)] [Department of Chemistry, University of Sistan and Baluchestan, Zahedan 98155-987 (Iran, Islamic Republic of); Bandrauk, A. D. [Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1 (Canada)] [Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1 (Canada); Lagmago Kamta, G. [Cancer Research Institute, Hopital C. LeMoyne, Greenfield Park, Québec J4V 2H1 (Canada)] [Cancer Research Institute, Hopital C. LeMoyne, Greenfield Park, Québec J4V 2H1 (Canada)

    2013-08-28

    We study enhanced single and double ionizations and enhanced single and double excitations in the nonsymmetric two-electron diatomic molecular ion HeH{sup +} in an intense ultrashort laser pulse linearly polarized along the internuclear axis (z axis). We solve a three-dimensional time-dependent Schrödinger equation, TDSE, via correlated two-electron ab initio calculations within the fixed-nuclei approximation. A complex scaling method is used for calculation of both single and double ionizations. These nonperturbative processes increase with large internuclear distance R and reach a maximum at some critical distance R{sub c} and decrease by further increase of R. This enhanced ionization (EI) at R{sub c} is accompanied by enhanced single and double excitation processes. Furthermore, EI is stronger when the permanent dipole moment of the molecule and the electric field at the peak of the laser pulse are antiparallel than when they are parallel. We predict analytically the R{sub c} at which the enhancement of all these molecular processes happens in HeH{sup +} from a simple quasistatic model and investigate the effect of Carrier Envelope Phase on these nonlinear nonperturbative processes.

  18. The bending triad of the quasi-spherical top molecule SO 2F 2 in the 550 cm -1 region

    NASA Astrophysics Data System (ADS)

    Rotger, M.; Boudon, V.; Loëte, M.; Zvereva-Loëte, N.; Margulès, L.; Demaison, J.; Merke, I.; Hegelund, F.; Bürger, H.

    2006-08-01

    The analysis of the ?3/ ?7/ ?9 bending triad of SO 2F 2 has been recently performed with the Watson's Hamiltonian up to octic terms employing 79 rovibrational parameters but including only the first order Coriolis interaction terms, fixed to ab initio values [H. Bürger, J. Demaison, F. Hegelund, L. Margulès, I. Merke, J. Mol. Struct. 612 (2002) 133-141]. Since SO 2F 2 is a quasi-spherical top, it can also be considered as derived from the SO42- sulfate ion. We have thus developed a new tensorial formalism in the O (3) ? Td ? C2 v group chain [M. Rotger, V. Boudon, M. Loëte, J. Mol. Spectrosc. 216 (2002) 297-307]. This approach allows a systematic development of rovibrational interactions and makes global analyses easier to perform even for complex polyad systems. We present here an application of this model to the analysis of the bending triad, with the same set of microwave assignments and almost the same set of infrared assignments as in the previous study of Bürger et al. It appears that we need to expand our Hamiltonian to a lower degree than the "classical" one (six instead of eight) when including also the second order Coriolis interactions. Our fit does not include more parameters. Furthermore, all of them are determined and the standard deviation of the rotational transitions is twice smaller. The analysis has been performed thanks to the C 2 v TDS program suite, which is freely available at the URL: http://www.u-bourgogne.fr/LPUB/c2vTDS.html.

  19. Birefringence arising from the reorientation of the polarizability anisotropy of molecules in collisionless gases

    NASA Technical Reports Server (NTRS)

    Lin, C. H.; Heritage, J. P.; Gustafson, T. K.; Chiao, R. Y.; Mctague, J. P.

    1976-01-01

    The refractive-index change in a collisionless gas is evaluated from the Stark shifts of the rotational energy levels that arise from the polarizability anisotropy. In the limit of an extremely-short-duration excitation, a multilevel coherent effect results in delayed refractive-index bursts. Both stationary and transient responses of this birefringence to an optical field are considered for symmetric-top molecules, with particular emphasis on the special case of linear molecules.

  20. Birefringing arising from the reorientation of the polarizability anisotropy of molecules in collisionless gases

    NASA Technical Reports Server (NTRS)

    Lin, C. H.; Heritage, J. P.; Gustafson, T. K.; Chiao, R. Y.; Mctague, J. P.

    1974-01-01

    The refractive index change in a collisionless gas is evaluated from the Stark shifts of the rotational energy levels that arise from the polarizability anisotropy. For the limit of an extremely short-duration excitation, a multilevel coherent effect resulted in delayed refractive index bursts. Both stationary and transient responses of this birefringence to an optical field were considered for symmetric top molecules, with particular emphasis on the special case of linear molecules.

  1. Rotational spectroscopy as a tool to investigate interactions between vibrational polyads in symmetric top molecules: Low-lying states v8 ? 2 of methyl cyanide, CH3CN

    NASA Astrophysics Data System (ADS)

    Müller, Holger S. P.; Brown, Linda R.; Drouin, Brian J.; Pearson, John C.; Kleiner, Isabelle; Sams, Robert L.; Sung, Keeyoon; Ordu, Matthias H.; Lewen, Frank

    2015-06-01

    Rotational and rovibrational spectra of methyl cyanide were recorded to analyze interactions in low-lying vibrational states and to construct line lists for radio astronomical observations as well as for infrared spectroscopic investigations of planetary atmospheres. The rotational spectra cover large portions of the 36-1627 GHz region. In the infrared (IR), a spectrum was recorded for this study in the region of 2?8 around 717 cm-1 with assignments covering 684-765 cm-1. Additional spectra in the ?8 region were used to validate the analysis. Information on the K level structure of CH3CN is almost exclusively obtained from IR spectra, as are basics of the J level structure. The large amount and the high accuracy of the rotational data improves knowledge of the J level structure considerably. Moreover, since these data extend to much higher J and K quantum numbers, they allowed us to investigate for the first time in depth local interactions between these states which occur at high K values. In particular, we have detected several interactions between v8 = 1 and 2. Notably, there is a strong ?v8 = ± 1 , ?K = 0 , ?l = ± 3 Fermi resonance between v8 =1-1 and v8 =2+2 at K = 14 . Pronounced effects in the spectrum are also caused by resonant ?v8 = ± 1 , ?K = ? 2 , ?l = ± 1 interactions between v8 = 1 and 2 at K = 13 , l = - 1 / K = 11 , l = 0 and at K = 15 , l = + 1 / K = 13 , l = + 2 . An equivalent resonant interaction occurs between K = 14 of the ground vibrational state and K = 12 , l = + 1 of v8 = 1 for which we present the first detailed account. A preliminary account was given in an earlier study on the ground vibrational state. Similar resonances were found for CH3CCH and, more recently, for CH3NC, warranting comparison of the results. From data pertaining to v8 = 2 , we also investigated rotational interactions with v4 = 1 as well as ?v8 = ± 1 , ?K = 0 , ?l = ± 3 Fermi interactions between v8 = 2 and 3. We have derived N2- and self-broadening coefficients for the ?8 , 2?8 -?8 , and 2?8 bands from previously determined ?4 values. Subsequently, we determined transition moments and intensities for the three IR bands.

  2. Opto-Electrical Cooling of Polar Molecules

    E-print Network

    M. Zeppenfeld; M. Motsch; P. W. H. Pinkse; G. Rempe

    2009-10-07

    We present an opto-electrical cooling scheme for polar molecules based on a Sisyphus-type cooling cycle in suitably tailored electric trapping fields. Dissipation is provided by spontaneous vibrational decay in a closed level scheme found in symmetric-top rotors comprising six low-field-seeking rovibrational states. A generic trap design is presented. Suitable molecules are identified with vibrational decay rates on the order of 100Hz. A simulation of the cooling process shows that the molecular temperature can be reduced from 1K to 1mK in approximately 10s. The molecules remain electrically trapped during this time, indicating that the ultracold regime can be reached in an experimentally feasible scheme.

  3. Two C3 -symmetric Dy3III complexes with triple di-?-methoxo-?-phenoxo bridges, magnetic ground state, and single-molecule magnetic behavior.

    PubMed

    Hänninen, Mikko M; Mota, Antonio J; Aravena, Daniel; Ruiz, Eliseo; Sillanpää, Reijo; Camón, Agustín; Evangelisti, Marco; Colacio, Enrique

    2014-07-01

    Two series of isostructural C(3)-symmetric Ln(3) complexes Ln(3)?[BPh(4)] and Ln(3)?0.33[Ln(NO(3))(6)] (in which Ln(III) =Gd and Dy) have been prepared from an amino-bis(phenol) ligand. X-ray studies reveal that Ln(III) ions are connected by one ?(2)-phenoxo and two ?(3)-methoxo bridges, thus leading to a hexagonal bipyramidal Ln(3)O(5) bridging core in which Ln(III) ions exhibit a biaugmented trigonal-prismatic geometry. Magnetic susceptibility studies and ab initio complete active space self-consistent field (CASSCF) calculations indicate that the magnetic coupling between the Dy(III) ions, which possess a high axial anisotropy in the ground state, is very weakly antiferromagnetic and mainly dipolar in nature. To reduce the electronic repulsion from the coordinating oxygen atom with the shortest Dy-O distance, the local magnetic moments are oriented almost perpendicular to the Dy(3) plane, thus leading to a paramagnetic ground state. CASSCF plus restricted active space state interaction (RASSI) calculations also show that the ground and first excited state of the Dy(III) ions are separated by approximately 150 and 177?cm(-1), for Dy(3)?[BPh(4)] and Dy(3)?0.33[Dy(NO(3))(6)], respectively. As expected for these large energy gaps, Dy(3)?[BPh(4)] and Dy(3)?0.33[Dy(NO(3)(6)] exhibit, under zero direct-current (dc) field, thermally activated slow relaxation of the magnetization, which overlap with a quantum tunneling relaxation process. Under an applied Hdc field of 1000?Oe, Dy(3)?[BPh(4)] exhibits two thermally activated processes with U(eff) values of 34.7 and 19.5?cm(-1), whereas Dy(3)?0.33[Dy(NO(3))(6)] shows only one activated process with Ueff =19.5?cm(-1). PMID:24890335

  4. Two dimensional symmetric correlation functions of the {hat S} operator and two dimensional Fourier transforms: Considering the line coupling for P and R lines of linear molecules

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

    The refinement of the Robert-Bonamy (RB) formalism by considering the line coupling for isotropic Raman Q lines of linear molecules developed in our previous study [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013)] has been extended to infrared P and R lines. In these calculations, the main task is to derive diagonal and off-diagonal matrix elements of the Liouville operator iS1 - S2 introduced in the formalism. When one considers the line coupling for isotropic Raman Q lines where their initial and final rotational quantum numbers are identical, the derivations of off-diagonal elements do not require extra correlation functions of the {hat S} operator and their Fourier transforms except for those used in deriving diagonal elements. In contrast, the derivations for infrared P and R lines become more difficult because they require a lot of new correlation functions and their Fourier transforms. By introducing two dimensional correlation functions labeled by two tensor ranks and making variable changes to become even functions, the derivations only require the latters' two dimensional Fourier transforms evaluated at two modulation frequencies characterizing the averaged energy gap and the frequency detuning between the two coupled transitions. With the coordinate representation, it is easy to accurately derive these two dimensional correlation functions. Meanwhile, by using the sampling theory one is able to effectively evaluate their two dimensional Fourier transforms. Thus, the obstacles in considering the line coupling for P and R lines have been overcome. Numerical calculations have been carried out for the half-widths of both the isotropic Raman Q lines and the infrared P and R lines of C2H2 broadened by N2. In comparison with values derived from the RB formalism, new calculated values are significantly reduced and become closer to measurements.

  5. Two Dimensional Symmetric Correlation Functions of the S Operator and Two Dimensional Fourier Transforms: Considering the Line Coupling for P and R Lines of Linear Molecules

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    The refinement of the Robert-Bonamy (RB) formalism by considering the line coupling for isotropic Raman Q lines of linear molecules developed in our previous study [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013)] has been extended to infrared P and R lines. In these calculations, the main task is to derive diagonal and off-diagonal matrix elements of the Liouville operator iS1 - S2 introduced in the formalism. When one considers the line coupling for isotropic Raman Q lines where their initial and final rotational quantum numbers are identical, the derivations of off-diagonal elements do not require extra correlation functions of the ^S operator and their Fourier transforms except for those used in deriving diagonal elements. In contrast, the derivations for infrared P and R lines become more difficult because they require a lot of new correlation functions and their Fourier transforms. By introducing two dimensional correlation functions labeled by two tensor ranks and making variable changes to become even functions, the derivations only require the latters' two dimensional Fourier transforms evaluated at two modulation frequencies characterizing the averaged energy gap and the frequency detuning between the two coupled transitions. With the coordinate representation, it is easy to accurately derive these two dimensional correlation functions. Meanwhile, by using the sampling theory one is able to effectively evaluate their two dimensional Fourier transforms. Thus, the obstacles in considering the line coupling for P and R lines have been overcome. Numerical calculations have been carried out for the half-widths of both the isotropic Raman Q lines and the infrared P and R lines of C2H2 broadened by N2. In comparison with values derived from the RB formalism, new calculated values are significantly reduced and become closer to measurements.

  6. Two dimensional symmetric correlation functions of the ? operator and two dimensional Fourier transforms: considering the line coupling for P and R lines of linear molecules.

    PubMed

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

    2014-03-14

    The refinement of the Robert-Bonamy (RB) formalism by considering the line coupling for isotropic Raman Q lines of linear molecules developed in our previous study [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013)] has been extended to infrared P and R lines. In these calculations, the main task is to derive diagonal and off-diagonal matrix elements of the Liouville operator iS1 - S2 introduced in the formalism. When one considers the line coupling for isotropic Raman Q lines where their initial and final rotational quantum numbers are identical, the derivations of off-diagonal elements do not require extra correlation functions of the ? operator and their Fourier transforms except for those used in deriving diagonal elements. In contrast, the derivations for infrared P and R lines become more difficult because they require a lot of new correlation functions and their Fourier transforms. By introducing two dimensional correlation functions labeled by two tensor ranks and making variable changes to become even functions, the derivations only require the latters' two dimensional Fourier transforms evaluated at two modulation frequencies characterizing the averaged energy gap and the frequency detuning between the two coupled transitions. With the coordinate representation, it is easy to accurately derive these two dimensional correlation functions. Meanwhile, by using the sampling theory one is able to effectively evaluate their two dimensional Fourier transforms. Thus, the obstacles in considering the line coupling for P and R lines have been overcome. Numerical calculations have been carried out for the half-widths of both the isotropic Raman Q lines and the infrared P and R lines of C2H2 broadened by N2. In comparison with values derived from the RB formalism, new calculated values are significantly reduced and become closer to measurements. PMID:24628166

  7. Symmetric Cryptography Asymmetric Cryptography

    E-print Network

    Ramkumar, Mahalingam

    Outline Symmetric Cryptography Asymmetric Cryptography Key Management Network Security Cryptography Symmetric Cryptography Asymmetric Cryptography Key Management Network Security 1 Symmetric Cryptography Symmetric Cryptography Overview Block Cipher Modes Multiple Encryption Hash Functions Message Authentication

  8. Ultrafast Electron Diffraction of Laser-Aligned CF3I Molecules

    NASA Astrophysics Data System (ADS)

    Hensley, Christopher; Yang, Jie; Centurion, Martin

    2012-06-01

    We present first experimental results of electron diffraction from non-adiabatically, laser-aligned molecules in the gas phase. Previous gas-phase diffraction studies have been successful in determining the structure of small molecules by comparing the data to theoretical models of the molecules. The random orientation of the molecules provides only 1D information (the interatomic distances), which makes it difficult to recover the structure of large molecules, or during conformational changes in the molecule where theoretical models cannot provide sufficient information. Using diffraction patterns from multiple projections of the aligned molecules it is possible to reconstruct the complete 3D structure of the symmetric top molecule (CF3I). The alignment angle is adjusted by rotating the direction of the laser polarization. An aligned distribution is created using a femtosecond laser pulse that excites a rotational wave packet causing the molecules to align along the direction of laser polarization around 2 ps after interaction with the laser pulse. Both the electron packet and the intense alignment field are generated using a 300-fs pulse centered at 800 nm. Our results are in good agreement with the previous findings and theoretical models for CF3I.

  9. Symmetric Novikov superalgebras

    SciTech Connect

    Ayadi, Imen; Benayadi, Saied [Laboratoire de Mathematiques et Applications de Metz, CNRS-UMR 7122, Universite Paul Verlaine-Metz, Ile du Saulcy, F-57045 Metz Cedex 1 (France)

    2010-02-15

    We study Novikov superalgebras with nondegenerate associative supersymmetric bilinear forms which are called symmetric Novikov superalgebras. We show that Novikov symmetric superalgebras are associative superalgebras with additional condition. Several examples of symmetric Novikov superalgebras are included, in particular, examples of symmetric Novikov superalgebras which are not 2-nilpotent. Finally, we introduce some notions of double extensions in order to give inductive descriptions of symmetric Novikov superalgebras.

  10. Symmetric Cryptography Asymmetric Cryptography

    E-print Network

    Ramkumar, Mahalingam

    Outline Trust Symmetric Cryptography Asymmetric Cryptography Key Management Network Security Cryptography - A Review Mahalingam Ramkumar Mississippi State University, MS September 22, 2006 Ramkumar Review #12;Outline Trust Symmetric Cryptography Asymmetric Cryptography Key Management Network Security 1

  11. Analytical Morse/long-Range model potential and predicted infrared and microwave spectra for a symmetric top-atom dimer: A case study of CH{sub 3}F–He

    SciTech Connect

    Ma, Yong-Tao; Li, Hui, E-mail: Prof-huili@jlu.edu.cn [Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, 2519 Jiefang Road, Changchun 130023 (China); Zeng, Tao [Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853 (United States)

    2014-06-07

    Four-dimensional ab initio intermolecular potential energy surfaces (PESs) for CH{sub 3}F–He that explicitly incorporates dependence on the Q{sub 3} stretching normal mode of the CH{sub 3}F molecule and are parametrically dependent on the other averaged intramolecular coordinates have been calculated. Analytical three-dimensional PESs for v{sub 3}(CH{sub 3}F) = 0 and 1 are obtained by least-squares fitting the vibrationally averaged potentials to the Morse/Long-Range potential function form. With the 3D PESs, we employ Lanczos algorithm to calculate rovibrational levels of the dimer system. Following some re-assignments, the predicted transition frequencies are in good agreement with experimental microwave data for ortho-CH{sub 3}F, with the root-mean-square deviation of 0.042 cm{sup ?1}. We then provide the first prediction of the infrared and microwave spectra for the para-CH{sub 3}F–He dimer. The calculated infrared band origin shifts associated with the ?{sub 3} fundamental of CH{sub 3}F are 0.039 and 0.069 cm{sup ?1} for para-CH{sub 3}F–He and ortho-CH{sub 3}F–He, respectively.

  12. Mighty Molecules

    NSDL National Science Digital Library

    Carlyn Little

    1997-01-01

    In this activity, learners use marshmallows and gum drops to construct seven models of molecules. Learners classify (solid, liquid or gas) and draw diagrams of the molecules. Learners can also create a table showing the chemical formula for each molecule and identify a common use for each chemical. Use this activity to introduce learners to molecules, compounds, and bonds.

  13. Oriented molecule beams: Focusing and orientation of t-butyl iodide with analysis by polarized laser photofragmentation

    NASA Astrophysics Data System (ADS)

    Xu, Qi-Xun; Jung, Kyung-Hoon; Bernstein, Richard B.

    1988-08-01

    The tert-butyl iodide molecule is readily focused with the electrostatic hexapole, via its first-order Stark effect as a pseudo-symmetric top. The pulsed, seeded supersonic focused beam, characterized by =Vth/ V0 (where ? is the angle between the molecular dipole axis ? and the electric field E; ±V0 the hexapole ``rod voltage,'' and Vth the so-called threshold voltage), passes into a small homogeneous electric field in which it is oriented. The degree of laboratory orientation achieved is measured using the method of linearly polarized laser-induced photofragmentation [S. R. Gandhi, T. J. Curtiss, and R. B. Bernstein, Phys. Rev. Lett. 59, 2951 (1987)], operating (at three laser wavelengths) on the I(2P3/2) and I(2P1/2) as well as the t-C4H9 radical photofragments. The results show that the oriented beam molecules of t-butyl iodide (at a rotational temperature near 15 K) have a higher degree of orientation than the prototype CH3I molecules (JKM state-selected and focused similarly), explainable by the greater importance of the so-called hyperfine disorientation effect for the prolate symmetric top (CH3I) than for the t-C4H9I. For the latter, orientations with photofragment up-down asymmetry ratios as large as a factor of 10 can be achieved, suggesting that t-C4H9I is an excellent candidate reagent for reactive asymmetry studies.

  14. A Thermodynamic Model of Phosphorus Distribution Ratio between CaO-SiO 2 -MgO-FeO-Fe 2 O 3 -MnO-Al 2 O 3 -P 2 O 5 Slags and Molten Steel during a Top–Bottom Combined Blown Converter Steelmaking Process Based on the Ion and Molecule Coexistence Theory

    Microsoft Academic Search

    Xue-Min Yang; Jian-Ping Duan; Cheng-Bin Shi; Meng Zhang; Yong-Liang Zhang; Jian-Chang Wang

    2011-01-01

    A thermodynamic model for calculating the phosphorus distribution ratio between top–bottom combined blown converter steelmaking\\u000a slags and molten steel has been developed by coupling with a developed thermodynamic model for calculating mass action concentrations\\u000a of structural units in the slags, i.e., CaO-SiO2-MgO-FeO-Fe2O3-MnO-Al2O3-P2O5 slags, based on the ion and molecule coexistence theory (IMCT). Not only the total phosphorus distribution ratio but

  15. Detecting internally symmetric protein structures

    Microsoft Academic Search

    Changhoon Kim; Jodi Basner; Byungkook Lee

    2010-01-01

    BACKGROUND: Many functional proteins have a symmetric structure. Most of these are multimeric complexes, which are made of non-symmetric monomers arranged in a symmetric manner. However, there are also a large number of proteins that have a symmetric structure in the monomeric state. These internally symmetric proteins are interesting objects from the point of view of their folding, function, and

  16. The system ammonium fluoride - cupric fluoride - water at zero degrees centigrade: A program for calculating the rotational spectrum of an asymmetric-top molecule in the microwave region on the IBM 650 digital computer.

    E-print Network

    Beal, James Burton

    1959-01-01

    TSE 8TSTBN ANNCEIUN FLUORIDE - CUPRIC FLUORIDE WATER AT ZERO UBCRR88 CRETIORADB A PROORAN FOR CALCULATINO T88 ROTATIONAL SPBCTRUN OP AN ASXNNETRIC TOP NOLECULE IE TKH NXCRCWAVE REOXQE OE THE IEN 650 QIQITAL CONPUTER A THESI8 Jaaes Burton Baal...YOSIUN PIIIORIDE CUPRIC FLUORIDE MATER AT EBRO DESRSES CESTIORADR A PROSRAN POR CALCULATI?G THE ROTATIOSAL SPECTRUN OP AI ASINNRTRZO TOP NOLRCULB IS THE NICROMAVE REOIGS ~ OW THE IRK 650 DIOITAL CONPSTRR A THSSZS Janee Rurton Seal, Jr, Approved ae to etre...

  17. Self-Assembling Dessert Toppings

    NSDL National Science Digital Library

    2012-12-27

    This is an activity (located on page 3 of the PDF) about self-assembly, the ability of molecules to assemble themselves according to certain rules. Learners will use food-grade components to create delicious dessert topping-filled gel capsules, macroscale relatives of the capsules nanoscientists make in a lab to carry medicine to targeted cells of the body. Relates to linked video, DragonflyTV Nano: Self-Assembly.

  18. Tops and Writhing DNA

    E-print Network

    Joseph Samuel; Supurna Sinha

    2010-11-30

    The torsional elasticity of semiflexible polymers like DNA is of biological significance. A mathematical treatment of this problem was begun by Fuller using the relation between link, twist and writhe, but progress has been hindered by the non-local nature of the writhe. This stands in the way of an analytic statistical mechanical treatment, which takes into account thermal fluctuations, in computing the partition function. In this paper we use the well known analogy with the dynamics of tops to show that when subjected to stretch and twist, the polymer configurations which dominate the partition function admit a local writhe formulation in the spirit of Fuller and thus provide an underlying justification for the use of Fuller's "local writhe expression" which leads to considerable mathematical simplification in solving theoretical models of DNA and elucidating their predictions. Our result facilitates comparison of the theoretical models with single molecule micromanipulation experiments and computer simulations.

  19. Hydrodynamic analysis of non-hard-core interactions in the rotational relaxation of molecules; ESR data

    Microsoft Academic Search

    Donna Hoel; Daniel Kivelson

    1975-01-01

    Molecular reorientation for symmetric tops is analyzed in terms of a stickiness factor (s) which measures, in terms of a hydrodynamic model, the lag of the fluid motion relative to that of the particle surface. For s = 1 and s = 0, the hydrodynamic problem is that of ’’stick’’ and ’’slip’’ boundary conditions for symmetric tops. For truly hydrodynamic

  20. PT-symmetric strings

    SciTech Connect

    Amore, Paolo, E-mail: paolo.amore@gmail.com [Facultad de Ciencias, CUICBAS, Universidad de Colima, Bernal Díaz del Castillo 340, Colima, Colima (Mexico); Fernández, Francisco M., E-mail: fernande@quimica.unlp.edu.ar [INIFTA (UNLP, CCT La Plata-CONICET), División Química Teórica, Diag. 113 y 64 (S/N), Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina); Garcia, Javier [INIFTA (UNLP, CCT La Plata-CONICET), División Química Teórica, Diag. 113 y 64 (S/N), Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina); Gutierrez, German [Facultad de Ciencias, CUICBAS, Universidad de Colima, Bernal Díaz del Castillo 340, Colima, Colima (Mexico)

    2014-04-15

    We study both analytically and numerically the spectrum of inhomogeneous strings with PT-symmetric density. We discuss an exactly solvable model of PT-symmetric string which is isospectral to the uniform string; for more general strings, we calculate exactly the sum rules Z(p)??{sub n=1}{sup ?}1/E{sub n}{sup p}, with p=1,2,… and find explicit expressions which can be used to obtain bounds on the lowest eigenvalue. A detailed numerical calculation is carried out for two non-solvable models depending on a parameter, obtaining precise estimates of the critical values where pair of real eigenvalues become complex. -- Highlights: •PT-symmetric Hamiltonians exhibit real eigenvalues when PT symmetry is unbroken. •We study PT-symmetric strings with complex density. •They exhibit regions of unbroken PT symmetry. •We calculate the critical parameters at the boundaries of those regions. •There are exact real sum rules for some particular complex densities.

  1. Creating a Symmetrical Design

    NSDL National Science Digital Library

    National Security Agency Central Security Service

    2009-04-24

    This unit teaches students the meaning of symmetry by having them manipulate a variety of objects. Using this knowledge, they will create a symmetrical design and write an informative paragraph about the quilt design and the importance of symmetry.

  2. Noncommutative spherically symmetric spaces

    SciTech Connect

    Murray, Sean; Govaerts, Jan [Centre for Cosmology, Particle Physics and Phenomenology, Universite catholique de Louvain, Chemin du Cyclotron 2, B-1348 Louvain-la-Neuve (Belgium); Centre for Cosmology, Particle Physics and Phenomenology, Universite catholique de Louvain, Chemin du Cyclotron 2, B-1348 Louvain-la-Neuve (Belgium) and International Chair in Mathematical Physics and Applications, University of Abomey-Calavi, 072 B. P. 50, Cotonou (Benin)

    2011-01-15

    We examine some noncommutative spherically symmetric spaces in three space dimensions. A generalization of Snyder's noncommutative (Euclidean) space allows the inclusion of the generator of dilations into the defining algebra of the coordinate and rotation operators. We then construct a spherically symmetric noncommutative Laplacian on this space having the correct limiting spectrum. This is presented via a creation and annihilation operator realization of the algebra, which may lend itself to a truncation of the Hilbert space.

  3. Raman spectroscopy of the N-C-O symmetric (?3) and antisymmetric (?2) stretch fundamentals in HNCO

    NASA Astrophysics Data System (ADS)

    Brown, Steven S.; Berghout, H. Laine; Crim, F. Fleming

    1997-12-01

    We report the first gas-phase Raman spectra of the N-C-O stretching fundamentals in isocyanic acid. Using stimulated Raman excitation to prepare vibrationally excited molecules, we record spectra via two different techniques, photoacoustic Raman spectroscopy and action spectroscopy. The former detects the sound wave generated as the Stokes laser tunes through resonances and deposits heat in the gas sample. The latter detects transitions by photodissociating the vibrationally excited states prepared in the vibrational excitation step and detecting the photofragments by laser induced fluorescence. In analogy with the stretching modes in CO2, the N-C-O symmetric stretch (?3) Raman fundamental in HNCO is strong while the antisymmetric stretch (?2) is weak, although neither is symmetry forbidden. Both vibrational states are strongly perturbed. The symmetric stretch interacts with combination states that contain two quanta of bending excitation, and the antisymmetric stretch interacts with several different combination states. Both Raman spectra have strong QQ branch rotational structure in which the band origins for different K sublevels in this near-prolate symmetric top follow no simple pattern. Photodissociation of the vibrationally excited states demonstrates the influence of the initial state preparation on the rotational resonances, photofragment appearance thresholds, and Franck-Condon factors in the transition to a dissociative excited electronic state.

  4. Interstellar molecules

    NASA Technical Reports Server (NTRS)

    Townes, C. H.

    1976-01-01

    Progress in the discovery and study of interstellar molecules is summarized. The 36 molecular species thus far identified in interstellar space are listed in several groups which include simple hydrides, oxides, and sulfides, various derivatives of ammonia, molecules involving linear carbon chains, cyanides, and molecules related in structure to formaldehyde, alcohols, or ethers. Several free radicals are described, the discovery of molecules in external galaxies is discussed, and possible mechanisms for molecular formation are noted. Methods for examining relative isotopic abundances by measuring molecules in interstellar clouds are outlined, mechanisms for the excitation of interstellar molecules are reviewed, and values are presented for the C-12/C-13 abundance ratio in a number of interstellar clouds. The detection of interstellar masers is discussed along with pumping mechanisms and masing transitions in H2CO, CH, OH, and SiO. The nature of dense interstellar clouds is examined in terms of several simple and complex cloud models, with emphasis on multiple condensation models.

  5. Single Molecules

    NSDL National Science Digital Library

    A new molecular science journal, Single Molecules, from Wiley Interscience, "will provide researchers with a broad overview of current methods and techniques, recent applications and shortcomings of present techniques in the field of single molecules." With temporary free access, the journal's latest issue contains a few full-text articles, with more articles being regularly added. This journal is currently calling for papers.

  6. Top physics at CDF

    SciTech Connect

    Julia Thom

    2004-06-24

    Precision studies of top quark properties are a primary goal of the Run II physics program at the Fermilab Tevatron. Marking the first stages of this program, the CDF collaboration presents recent results on top pair production cross section, single top physics and top mass, using between 109 and 200 pb{sup -1} of Run II data.

  7. The symmetric method 

    E-print Network

    Strub, James Earl

    1962-01-01

    = T and the proof of' (2) III. C~ PROGRAM OF THE SYMMETRIC METHOD Descri ion The computer program oi' the Symmetric Method is in the form of a FAP subroutine for the IBM 709/7090. This subroutine is compatible with either FORTRAN or FAP calling programs and... includes 2' locations for P snd thus permits an n of 244 if the calling program hss 29, 890 locations available for the array A. Csllin Se uence Be irements A FORTRAN calling program will use the statement CALL SYMINV(ApNpDELTA~INDCTR) where...

  8. Braids, shuffles and symmetrizers

    NASA Astrophysics Data System (ADS)

    Isaev, A. P.; Ogievetsky, O. V.

    2009-07-01

    Multiplicative analogues of the shuffle elements of the braid group rings are introduced; in local representations they give rise to certain graded associative algebras (b-shuffle algebras). For the Hecke and BMW algebras, the (anti)-symmetrizers have simple expressions in terms of the multiplicative shuffles. The (anti)-symmetrizers can be expressed in terms of the highest multiplicative 1-shuffles (for the Hecke and BMW algebras) and in terms of the highest additive 1-shuffles (for the Hecke algebras). The spectra and multiplicities of eigenvalues of the operators of the multiplication by the multiplicative and additive 1-shuffles are examined. Dedicated to the memory of Aleosha Zamolodchikov.

  9. Molecule Polarity

    NSDL National Science Digital Library

    The PhET project at the University of Colorado creates "fun, interactive, research-based simulations of physical phenomena." This particular one deals with molecular polarity. When is a molecule polar? Change the electronegativity of atoms in a molecule to see how it affects polarity. This simulation will allow visitors to see how molecules behave in an electric field, and change the bond angle to see how shape affects polarity for real molecules in 3D. The simulation is also paired with teaching tips and user-contirubed Teaching Ideas, lessons using the simulation in context, that can be found near the bottom of the page. The simulation is also available in multiple languages.

  10. Modeling Molecules

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The molecule modeling method known as Multibody Order (N) Dynamics, or MBO(N)D, was developed by Moldyn, Inc. at Goddard Space Flight Center through funding provided by the SBIR program. The software can model the dynamics of molecules through technology which stimulates low-frequency molecular motions and properties, such as movements among a molecule's constituent parts. With MBO(N)D, a molecule is substructured into a set of interconnected rigid and flexible bodies. These bodies replace the computation burden of mapping individual atoms. Moldyn's technology cuts computation time while increasing accuracy. The MBO(N)D technology is available as Insight II 97.0 from Molecular Simulations, Inc. Currently the technology is used to account for forces on spacecraft parts and to perform molecular analyses for pharmaceutical purposes. It permits the solution of molecular dynamics problems on a moderate workstation, as opposed to on a supercomputer.

  11. Symmetrohedra: Polyhedra from Symmetric

    E-print Network

    Kaplan, Craig S.

    Symmetrohedra: Polyhedra from Symmetric Placement of Regular Polygons Craig S. Kaplan University://www.georgehart.com george@georgehart.com Abstract In the quest for new visually interesting polyhedra with regular faces, we axes of a polyhedral symmetry group. This new technique can be used to generate many existing polyhedra

  12. Top quark physics

    SciTech Connect

    Ahmadov, A.; Azuelos, G.; Bauer, U.; Belyaev, A.; Berger, E. L.; Sullivan, Z.; Tait, T. M. P.

    2000-03-24

    The top quark, when it was finally discovered at Fermilab in 1995 completed the three-generation structure of the Standard Model (SM) and opened up the new field of top quark physics. Viewed as just another SM quark, the top quark appears to be a rather uninteresting species. Produced predominantly, in hadron-hadron collisions, through strong interactions, it decays rapidly without forming hadrons, and almost exclusively through the single mode t {r_arrow} Wb. The relevant CKM coupling V{sub tb} is already determined by the (three-generation) unitarity of the CKM matrix. Rare decays and CP violation are unmeasurable small in the SM. Yet the top quark is distinguished by its large mass, about 35 times larger than the mass of the next heavy quark, and intriguingly close to the scale of electroweak (EW) symmetry breaking. This unique property raises a number of interesting questions. Is the top quark mass generated by the Higgs mechanism as the SM predicts and is its mass related to the top-Higgs-Yukawa coupling? Or does it play an even more fundamental role in the EW symmetry breaking mechanism? If there are new particles lighter than the top quark, does the top quark decay into them? Could non-SM physics first manifest itself in non-standard couplings of the top quark which show up as anomalies in top quark production and decays? Top quark physics tries to answer these questions. Several properties of the top quark have already been examined at the Tevatron. These include studies of the kinematical properties of top production, the measurements of the top mass, of the top production cross-section, the reconstruction of t{bar t}pairs in the fully hadronic final states, the study of {tau} decays of the top quark, the reconstruction of hadronic decays of the W boson from top decays, the search for flavor changing neutral current decays, the measurement of the W helicity in top decays, and bounds on t{bar t} spin correlations. Most of these measurements are limited by the small sample of top quarks collected at the Tevatron up to now. The LHC is, in comparison, a top factory, producing about 8 million t{bar t}pairs per experiment per year at low luminosity (10 fb{sup {minus}1}/year), and another few million (anti-)tops in EW single (anti-)top quark production. They therefore expect that top quark properties can be examined with significant precision at the LHC. Entirely new measurements can be contemplated on the basis of the large available statistics.

  13. Static cylindrically symmetric spacetimes

    NASA Astrophysics Data System (ADS)

    Fjällborg, Mikael

    2007-05-01

    We prove the existence of static solutions to the cylindrically symmetric Einstein Vlasov system, and we show that the matter cylinder has finite extension in two of the three spatial dimensions. The same results are also proved for a quite general class of equations of state for perfect fluids coupled to the Einstein equations, extending the class of equations of state considered by Bicak et al (2004 Class. Quantum Grav.21 1583). We also obtain this result for the Vlasov Poisson system.

  14. Investigating Movement of Tops

    NSDL National Science Digital Library

    This is a guided inquiry lesson using tops to teach the students how to raise questions and seek answers by making careful observations. They will note what happens when they explore the tops and then share their results with others.

  15. Tinkering with Tops

    NSDL National Science Digital Library

    IEEE

    2014-05-22

    In this activity, learners explore the history, design and motion of spinning tops. Learners work in teams of "engineers" to design and build their own tops out of everyday items. Their challenge is to design a spinning top that can spin for at least 10 seconds within a circle 30 cm in diameter.

  16. Spherical Tippe Tops

    ERIC Educational Resources Information Center

    Cross, Rod

    2013-01-01

    A tippe top (see Fig. 1) is usually constructed as a truncated sphere with a cylindrical peg on top, as indicated in Fig. 2(a). When spun rapidly on a horizontal surface, a tippe top spins about a vertical axis while rotating slowly about a horizontal axis until the peg touches the surface. At that point, weight is transferred to the peg, the…

  17. Biological Molecules

    NSDL National Science Digital Library

    Paul Anderson

    2013-03-12

    Paul Anderson describes the four major biological molecules found in living things. He begins with a brief discussion of polymerization. Dehydration synthesis is used to connect monomers into polymers and hydrolysis breaks them down again. The major characteristics of nucleic acids are described as well as there directionality from 3' to 5' end.

  18. Top physics at CDF

    SciTech Connect

    Schwarz, Thomas A.; /UC, Davis

    2008-07-01

    Recent results in top physics at CDF presented at the Lake Louise Winter Institute 2008 are discussed, including updates to the top mass, single top search, a search for flavor changing neutral currents in top decay, and W-helicity measurements. Several newer measurements are also presented including the forward-backward asymmetry, the t{bar t} differential cross-section d{sigma}/dM{sub t{bar t}}, and a search for top pair production from massive gluons. Most of the discussed measurements utilize close to 2 fb{sup -1} of data collected at CDF.

  19. Small Molecule Inhibitors of Anthrax Lethal Factor Toxin

    PubMed Central

    Williams, John D.; Khan, Atiyya R.; Cardinale, Steven C.; Butler, Michelle M.; Bowlin, Terry L.; Peet, Norton P.

    2014-01-01

    This manuscript describes the preparation of new small molecule inhibitors of Bacillus anthracis lethal factor. Our starting point was the symmetrical, bis-quinolinyl compound 1 (NSC 12155). Optimization of one half of this molecule led to new LF inhibitors that were desymmetrized to afford more drug-like compounds. PMID:24290062

  20. Moving Molecules!

    NSDL National Science Digital Library

    2014-06-24

    In this activity about molecular diffusion (located on page 2 of the PDF), learners will make predictions and move molecules of iodine through a seemingly solid plastic sandwich bag. The process of diffusion will be visually indicated by a color change when the iodine reacts with starch inside the bag. Information in the resource explains how this activity relates to nanoparticles and research. Related to linked video, DragonflyTV Nano: Nanosilver.

  1. One-dimensional hydrogen atom and hydrogen molecule ion in momentum space

    Microsoft Academic Search

    I. Richard Lapidus

    1983-01-01

    The momentum-space wave functions have been obtained for the one-dimensional hydrogen atom and the symmetric and antisymmetric states of the one-dimensional hydrogen molecule ion with delta-function interactions between the particles. The uncertainty relation has been evaluated as a function of the distance between the nuclei in the molecule ion. For the symmetric state this is finite for the collapsed molecule.

  2. Top Quark Mass Measurements

    E-print Network

    A. P. Heinson; for the CDF Collaboration; D0 Collaboration

    2006-09-18

    First observed in 1995, the top quark is one of a pair of third-generation quarks in the Standard Model of particle physics. It has charge +2/3e and a mass of 171.4 GeV, about 40 times heavier than its partner, the bottom quark. The CDF and D0 collaborations have identified several hundred events containing the decays of top-antitop pairs in the large dataset collected at the Tevatron proton-antiproton collider over the last four years. They have used these events to measure the top quark's mass to nearly 1% precision and to study other top quark properties. The mass of the top quark is a fundamental parameter of the Standard Model, and knowledge of its value with small uncertainty allows us to predict properties of the as-yet-unobserved Higgs boson. This paper presents the status of the measurements of the top quark mass.

  3. Tevatron top AFB versus LHC top physics

    NASA Astrophysics Data System (ADS)

    Gresham, Moira I.; Kim, Ian-Woo; Zurek, Kathryn M.

    2012-01-01

    We carry out a comprehensive analysis of models for top AFB at CDF in light of new top data arriving from the LHC. We begin with a careful Tevatron analysis, considering in general which sets of effective vertices give rise to a large forward-backward asymmetry while suppressing the contribution to the total tt¯ cross-section. We show on general grounds that scalar models struggle to produce sufficient asymmetries consistent with CDF observations, while vector models can produce a large asymmetry with a less significant tension in the total cross-section and tt¯ invariant mass distribution at the Tevatron. We examine the essential observables of these models for top physics at LHC7 with 1fb-1 of data, including the total cross-section, invariant mass distribution and number of additional jets in tt¯ events. In the case of t-channel mediators, the LHC total cross-section places a strong constraint on light mediators, while the Tevatron invariant mass distributions place strong constraints on heavy mediators that are able to produce the asymmetry. In particular, single mediator production at the LHC can contribute significantly to tt¯+jets events and lead to a significant increase in the tt¯ cross-section, as well as in the ratio of top pair events with extra jets to events with no extra jets. Heavy axigluons are becoming increasingly squeezed by LHC7 tt¯ and dijet resonance searches. We conclude that LHC7 top analyses are rapidly closing the window for viable models of the CDF top AFB.

  4. Top Physics at CDF

    SciTech Connect

    Moon, Chang-Seong

    2011-06-01

    We present the recent results of top-quark physics using up to 6 fb{sup -1} of p{bar p} collisions at a center of mass energy of {radical}s = 1.96 TeV analyzed by the CDF collaboration. Thanks to this large data sample, precision top quark measurements are now a reality at the Tevatron. Further, several new physics signals could appear in this large dataset. We will present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.

  5. Top Physics at CDF

    E-print Network

    Chang-Seong Moon

    2011-07-01

    We present the recent results of top-quark physics using up to 6 fb$^{-1}$ of $p \\bar p$ collisions at a center of mass energy of $\\sqrt s$ = 1.96 TeV analyzed by the CDF collaboration. Thanks to this large data sample, precision top quark measurements are now a reality at the Tevatron. Further, several new physics signals could appear in this large dataset. We will present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.

  6. Building Molecules

    NSDL National Science Digital Library

    Rensselaer Polytechnic Institute

    2005-01-01

    This online interactive has three activities in the NanoLab (press the upper right button): Build, Zoom, and Transform. In Build, learners build increasingly complex molecules out of carbon, oxygen, and hydrogen, and is useful for connecting subscripts and the number of atoms, and for introducing 3D molecular structures which are automatically built. Zoom is a "powers of 10" zoom-in ranging from 10,000 kilometers to 1 nanometer. Transform is a simulation of water changing phase from solid to liquid to gas. Through exploration of the site learners form a better understanding of the composition of matter.

  7. Optimal symmetric flight studies

    NASA Technical Reports Server (NTRS)

    Weston, A. R.; Menon, P. K. A.; Bilimoria, K. D.; Cliff, E. M.; Kelley, H. J.

    1985-01-01

    Several topics in optimal symmetric flight of airbreathing vehicles are examined. In one study, an approximation scheme designed for onboard real-time energy management of climb-dash is developed and calculations for a high-performance aircraft presented. In another, a vehicle model intermediate in complexity between energy and point-mass models is explored and some quirks in optimal flight characteristics peculiar to the model uncovered. In yet another study, energy-modelling procedures are re-examined with a view to stretching the range of validity of zeroth-order approximation by special choice of state variables. In a final study, time-fuel tradeoffs in cruise-dash are examined for the consequences of nonconvexities appearing in the classical steady cruise-dash model. Two appendices provide retrospective looks at two early publications on energy modelling and related optimal control theory.

  8. Minimally symmetric Higgs boson

    NASA Astrophysics Data System (ADS)

    Low, Ian

    2015-06-01

    Models addressing the naturalness of a light Higgs boson typically employ symmetries, either bosonic or fermionic, to stabilize the Higgs mass. We consider a setup with the minimal amount of symmetries: four shift symmetries acting on the four components of the Higgs doublet, subject to the constraints of linearly realized S U (2 )L×U (1 )Y electroweak symmetry. Up to terms that explicitly violate the shift symmetries, the effective Lagrangian can be derived, irrespective of the spontaneously broken group G in the ultraviolet, and is universal among all models where the Higgs arises as a pseudo-Nambu-Goldstone boson. Very high energy scatterings of vector bosons could provide smoking gun signals of a minimally symmetric Higgs boson.

  9. ccsd00003900, ON SYMMETRIC SENSITIVITY

    E-print Network

    ccsd­00003900, version 1 ­ 14 Jan 2005 ON SYMMETRIC SENSITIVITY Benoît CADRE and Pierre JACOB UMR, 34095 Montpellier cedex 5, FRANCE Abstract We de#28;ne the concept of symmetric sensitivity with respect sensitive map may diverge from a positive quantity independent of the initial points. We study

  10. Training Top 125

    ERIC Educational Resources Information Center

    Training, 2012

    2012-01-01

    The best learning and development organizations support business initiatives tactically "and" help drive strategic change. Verizon did just that, earning it the No. 1 spot for the first time on the Training Top 125. Verizon and the other 2012 Top 125 winners continued to invest in training, collectively dedicating a mean of 4.52 percent of their…

  11. Experimental Support for the Evolution of Symmetric Protein Architecture from a Simple Peptide Motif

    SciTech Connect

    J Lee; M Blaber

    2011-12-31

    The majority of protein architectures exhibit elements of structural symmetry, and 'gene duplication and fusion' is the evolutionary mechanism generally hypothesized to be responsible for their emergence from simple peptide motifs. Despite the central importance of the gene duplication and fusion hypothesis, experimental support for a plausible evolutionary pathway for a specific protein architecture has yet to be effectively demonstrated. To address this question, a unique 'top-down symmetric deconstruction' strategy was utilized to successfully identify a simple peptide motif capable of recapitulating, via gene duplication and fusion processes, a symmetric protein architecture (the threefold symmetric {beta}-trefoil fold). The folding properties of intermediary forms in this deconstruction agree precisely with a previously proposed 'conserved architecture' model for symmetric protein evolution. Furthermore, a route through foldable sequence-space between the simple peptide motif and extant protein fold is demonstrated. These results provide compelling experimental support for a plausible evolutionary pathway of symmetric protein architecture via gene duplication and fusion processes.

  12. The Single Top Quark Physics

    E-print Network

    E. Boos; L. Dudko

    2012-11-30

    The single top quark production has an electroweak nature and provides an additional to the top pair production source of the top quarks. The processes involving single top have unique properties, they are very interesting from both theoretical and experimental view points. Short review of the single top quark production processes is given in the paper.

  13. Top Quark Properties

    E-print Network

    Yvonne Peters; for the Atlas Collaboration; CDF Collaboration; CMS Collaboration; D0 Collaboration

    2011-12-02

    Since its discovery in 1995 by the CDF and D0 collaborations at the Fermilab Tevatron collider, the top quark has undergone intensive studies. Besides the Tevatron experiments, with the start of the LHC in 2010 a top quark factory started its operation. It is now possible to measure top quark properties simultaneously at four different experiments, namely ATLAS and CMS at LHC and CDF and D0 at Tevatron. Having collected thousands of top quarks each, several top quark properties have been measured precisely, while others are being measured for the first time. In this article, recent measurements of top quark properties from ATLAS, CDF, CMS and D0 are presented, using up to 5.4 fb-1 of integrated luminosity at the Tevatron and 1.1 fb^-1 at the LHC. In particular, measurements of the top quark mass, mass difference, forward backward charge asymmetry, tt - spin correlations, the ratio of branching fractions, W helicity, anomalous couplings, color flow and the search for flavor changing neutral currents are discussed.

  14. Top Quark Properties

    SciTech Connect

    Peters, Yvonne

    2011-12-01

    Since its discovery in 1995 by the CDF and D0 collaborations at the Fermilab Tevatron collider, the top quark has undergone intensive studies. Besides the Tevatron experiments, with the start of the LHC in 2010 a top quark factory started its operation. It is now possible to measure top quark properties simultaneously at four different experiments, namely ATLAS and CMS at LHC and CDF and D0 at Tevatron. Having collected thousands of top quarks each, several top quark properties have been measured precisely, while others are being measured for the first time. In this article, recent measurements of top quark properties from ATLAS, CDF, CMS and D0 are presented, using up to 5.4 fb{sup -1} of integrated luminosity at the Tevatron and 1.1 fb{sup -1} at the LHC. In particular, measurements of the top quark mass, mass difference, foward backward charge asymmetry, t{bar t} spin correlations, the ratio of branching fractions, W helicity, anomalous couplings, color flow and the search for flavor changing neutral currents are discussed.

  15. Minimal Residual Methods for Complex Symmetric, Skew Symmetric ...

    E-print Network

    Sou-Cheng (Terrya) Choi

    2013-04-26

    Apr 26, 2013 ... three-term recurrent complex-symmetric Lanczos process. Whether the ... (1975) with enhanced stability and capability. Key words. .... k in subscripts or superscripts denote integer indices, otherwise they may represent. ?.

  16. Achromatic axially symmetric wave plate.

    PubMed

    Wakayama, Toshitaka; Komaki, Kazuki; Otani, Yukitoshi; Yoshizawa, Toru

    2012-12-31

    An achromatic axially symmetric wave plate (AAS-WP) is proposed that is based on Fresnel reflections. The wave plate does not introduce spatial dispersion. It provides retardation in the wavelength domain with an axially symmetric azimuthal angle. The optical configuration, a numerical simulation, and the optical properties of the AAS-WP are described. It is composed of PMMA. A pair of them is manufactured on a lathe. In the numerical simulation, the achromatic angle is estimated and is used to design the devices. They generate an axially symmetric polarized beam. The birefringence distribution is measured in order to evaluate the AAS-WPs. PMID:23388751

  17. Axially Symmetric Black Hole Skyrmions

    E-print Network

    Sawado, N; Sawado, Nobuyuki; Shiiki, Noriko

    2003-01-01

    It has been known that a B=2 skyrmion is axially symmetric. We consider the Skyrme model coupled to gravity and obtain static axially symmetric black hole solutions numerically. The black hole skyrmion no longer has integer baryonic charge but has fractional charge outside the horizon as in the spherically symmetric case. Therefore, the solution represents a black hole partially swallowing a deuteron. Recent studies of theories with large extra dimensions suggest an effective Planck scale of order a TeV and thus the deuteron black hole may be produced in the Linear Hadron Collider (LHC) in future.

  18. Symmetric M-Theory Backgrounds

    E-print Network

    Figueroa-O'Farrill, José

    2011-01-01

    We classify symmetric backgrounds of eleven-dimensional supergravity up to local isometry. In other words, we classify triples (M,g,F), where (M,g) is an eleven-dimensional lorentzian locally symmetric space and F is an invariant 4-form, satisfying the equations of motion of eleven-dimensional supergravity. The possible (M,g) are given either by (not necessarily nondegenerate) Cahen-Wallach spaces or by products AdS_d x M for 1 < d < 8 and M a not necessarily irreducible riemannian symmetric space of dimension 11-d. In most cases we determine the corresponding F-moduli spaces.

  19. Differential Targeting of Human Topoisomerase II Isoforms with Small Molecules.

    PubMed

    Mariani, Angelica; Bartoli, Alexandra; Atwal, Mandeep; Lee, Ka C; Austin, Caroline A; Rodriguez, Raphaël

    2015-06-11

    The TOP2 poison etoposide has been implicated in the generation of secondary malignancies during cancer treatment. Structural similarities between TOP2 isoforms challenge the rational design of isoform-specific poisons to further delineate these processes. Herein, we describe the synthesis and biological evaluation of a focused library of etoposide analogues, with the identification of two novel small molecules exhibiting TOP2B-dependent toxicity. Our findings pave the way toward studying isoform-specific cellular processes by means of small molecule intervention. PMID:25945730

  20. Symmetry-Based Techniques for Qualitative Understanding of Rovibrational Effects in Spherical-Top Molecular Spectra and Dynamics

    NASA Astrophysics Data System (ADS)

    Mitchell, Justin Chadwick

    2011-12-01

    Using light to probe the structure of matter is as natural as opening our eyes. Modern physics and chemistry have turned this art into a rich science, measuring the delicate interactions possible at the molecular level. Perhaps the most commonly used tool in computational spectroscopy is that of matrix diagonalization. While this is invaluable for calculating everything from molecular structure and energy levels to dipole moments and dynamics, the process of numerical diagonalization is an opaque one. This work applies symmetry and semi-classical techniques to elucidate numerical spectral analysis for high-symmetry molecules. Semi-classical techniques, such as the Potential Energy Surfaces, have long been used to help understand molecular vibronic and rovibronic spectra and dynamics. This investigation focuses on newer semi-classical techniques that apply Rotational Energy Surfaces (RES) to rotational energy level clustering effects in high-symmetry molecules. Such clusters exist in rigid rotor molecules as well as deformable spherical tops. This study begins by using the simplicity of rigid symmetric top molecules to clarify the classical-quantum correspondence of RES semi-classical analysis and then extends it to a more precise and complete theory of modern high-resolution spectra. RES analysis is extended to molecules having more complex and higher rank tensorial rotational and rovibrational Hamiltonians than were possible to understand before. Such molecules are shown to produce an extraordinary range of rotational level clusters, corresponding to a panoply of symmetries ranging from C4v to C2 and C1 (no symmetry) with a corresponding range of new angular momentum localization and J-tunneling effects. Using RES topography analysis and the commutation duality relations between symmetry group operators in the lab-frame to those in the body-frame, it is shown how to better describe and catalog complex splittings found in rotational level clusters. Symmetry character analysis is generalized to give analytic eigensolutions. An appendix provides vibrational analogies. For the first time, interactions between molecular vibrations (polyads) are described semi-classically by multiple RES. This is done for the nu 3/2nu4 dyad of CF4. The nine-surface RES topology of the U(9)-dyad agrees with both computational and experimental work. A connection between this and a simpler U(2) example is detailed in an Appendix.

  1. Top physics: CDF results

    SciTech Connect

    K. Bloom

    2004-06-23

    The top quark plays an important role in the grand scheme of particle physics, and is also interesting on its own merits. We present recent results from CDF on top-quark physics based on 100-200 pb{sup -1} of p{bar p} collision data. We have measured the t{bar t} cross section in different decay modes using several different techniques, and are beginning our studies of top-quark properties. New analyses for this conference include a measurement of {sigma}{sub t{bar t}} in the lepton-plus-jets channel using a neural net to distinguish signal and background events, and measurements of top-quark branching fractions.

  2. Tops, bottoms and versatiles

    Microsoft Academic Search

    David A. Moskowitz; Gerulf Rieger; Michael E. Roloff

    2008-01-01

    Amongst gay men, the self-label – top, bottom or versatile – reflects the sexual role preference during anal intercourse. This study explored whether this label could predict preferences for other sexual behaviors and the roles within those behaviors. First, the accuracy of the sexual self-label was tested. We confirmed that tops strongly preferred insertive anal intercourse; bottoms, receptive anal intercourse; and versatiles, both behaviors.

  3. Spectra of Confined Atoms and Molecules

    Microsoft Academic Search

    D. Bielinska-Waz

    2003-01-01

    The properties of spectra of atoms and molecules confined by an external potential are analyzed. The effects of spatial confinement are studied using quantum-chemical models. The confinement of the system is described by an external one-particle potential. Two-electron atoms confined in a spherically symmetric harmonic oscillator potential are investigated in detail [1]. In this case the interplay between the effects

  4. SYMMETRIC TENSOR DECOMPOSITION Jerome Brachat

    E-print Network

    Paris-Sud XI, Université de

    for symmetric tensors whose rank did not exceed dimension [10] [11]. Now, it has become possible to estimate not fully exploit symmetries [16], minimize different succes- sive criteria sequentially [17] [18

  5. Cold collisions of complex polyatomic molecules.

    PubMed

    Li, Zhiying; Heller, Eric J

    2012-02-01

    We introduce a method for classical trajectory calculations to simulate collisions between atoms and large rigid asymmetric-top molecules. We investigate the formation of molecule-helium complexes in buffer-gas cooling experiments at a temperature of 6.5 K for molecules as large as naphthalene. Our calculations show that the mean lifetime of the naphthalene-helium quasi-bound collision complex is not long enough for the formation of stable clusters under the experimental conditions. Our results suggest that it may be possible to improve the efficiency of the production of cold molecules in buffer-gas cooling experiments by increasing the density of helium. In addition, we find that the shape of molecules is important for the collision dynamics when the vibrational motion of molecules is frozen. For some molecules, it is even more crucial than the number of accessible degrees of freedom. This indicates that by selecting molecules with suitable shape for buffer-gas cooling, it may be possible to cool molecules with a very large number of degrees of freedom. PMID:22320741

  6. Top quark physics: Future measurements

    SciTech Connect

    Frey, R. [Univ. of Oregon, Eugene, OR (United States). Dept. of Physics; Vejcik, S. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Physics; Berger, E.L. [Argonne National Lab., IL (United States)] [and others

    1997-04-04

    The authors discuss the study of the top quark at future experiments and machines. Top`s large mass makes it a unique probe of physics at the natural electroweak scale. They emphasize measurements of the top quark`s mass, width, and couplings, as well as searches for rare or nonstandard decays, and discuss the complementary roles played by hadron and lepton colliders.

  7. Top Quark Measurements in CMS

    E-print Network

    Efe Yazgan; for the CMS Collaboration

    2014-09-12

    Measurements involving top quarks provide important tests of QCD. A selected set of top quark measurements in CMS including the strong coupling constant, top quark pole mass, constraints on parton distribution functions, top quark pair differential cross sections, ttbar+0 and >0 jet events, top quark mass studied using various kinematic variables in different phase-space regions, and alternative top quark mass measurements is presented. The evolution of expected uncertainties in future LHC runs for the standard and alternative top quark mass measurements is also presented.

  8. Top quark production at CDF

    SciTech Connect

    Moed, Shulamit; /Harvard U.

    2010-01-01

    The large data samples of top quark candidate events collected at the Tevatron CDF II experiment allow for a variety of measurements to analyze the production of the top quark. This article discusses recent results of top quark production at CDF presented at the SUSY09 conference, including updates to the top pair production cross section, forward-backward asymmetry in t{bar t} production, single top search, search for top resonances and a search for heavy top. The discussed measurements utilize up to 3.2 fb{sup -1} of integrated luminosity collected at CDF.

  9. Top Quark Production at CDF

    SciTech Connect

    Moed, Shulamit [Harvard University, Laboratory for Particle Physics and Cosmology, 18 Hammond St., Cambridge, MA, 02138 (United States)

    2010-02-10

    The large data samples of top quark candidate events collected at the Tevatron CDF II experiment allow for a variety of measurements to analyze the production of the top quark. This article discusses recent results of top quark production at CDF presented at the SUSY09 conference, including updates to the top pair production cross section, forward-backward asymmetry in tt-bar production, single top search, search for top resonances and a search for heavy top. The discussed measurements utilize up to 3.2 fb{sup -1} of integrated luminosity collected at CDF.

  10. Top-ophilia

    SciTech Connect

    Quigg, Chris; /Fermilab

    2008-01-01

    Almost from the moment in June 1977 when the discovery of the Upsilon resonance revealed the existence of what we now call the bottom quark, physicists began searching for its partner. Through the years, as we established the electric charge and weak isospin of the b-quark, and detected the virtual influence of its mate, it became clear that the top quark must exist. Exactly at what mass, we couldn't say, but we knew just how top events would look. We also knew that top events would be rare--if the Tevatron could make them at all--and that picking out the events would pose a real challenge for the experimenters and their detectors.

  11. ATLAS results on top properties

    E-print Network

    F. Derue

    2014-08-26

    Recent measurements of top quark properties using $t{\\bar t}$ events produced in proton-proton collisions at the Large Hadron Collider with centre of mass energies of 7 and 8 TeV and detected by the ATLAS experiment are presented. These results include top quark mass, the top and anti-top mass difference, the electric charge, the top quark polarization and spin correlation, the $t{\\bar t}$ charge asymmetry and the search for flavour changing neutral currents.

  12. Broadening and shifting of the methanol 119 {mu}m gain line of linear and circular polarization by collision with chiral molecules

    SciTech Connect

    J.S. Bakos; G. Djotyan; Zsuzsa Soerlei; J. Szigeti; D. K. Mansfield; J. Sarkozi

    2000-06-21

    Evidence of circular dichroism has been observed in the spectral properties of a gas of left-right symmetric molecules. This dichroism comes about as the result of collisions of the symmetric molecules with left-right asymmetric molecules introduced as a buffer gas. In this sense, the dichroism can be said to have been transferred from the chiral buffer molecules to the symmetric, non-chiral molecules of the background vapor. This transferred dichroism appears as broadening in the gain line of the symmetric molecule which is asymmetric with respect to the right or left handedness of a circularly polarized probe. The broadening of the 119 {mu}m line of the methanol molecule was observed using infrared-far infrared double resonance spectroscopy.

  13. Existence of symmetric central configurations

    NASA Astrophysics Data System (ADS)

    Montaldi, James

    2015-06-01

    Central configurations have been of great interest over many years, with the earliest examples due to Euler and Lagrange. There are numerous results in the literature demonstrating the existence of central configurations with specific symmetry properties, using slightly different techniques in each. The aim here is to describe a uniform approach by adapting to the symmetric case the well-known variational argument showing the existence of central configurations. The principal conclusion is that there is a central configuration for every possible symmetry type, and for any symmetric choice of masses. Finally the same argument is applied to the class of balanced configurations introduced by Albouy and Chenciner.

  14. Looking for symmetric Bell inequalities

    NASA Astrophysics Data System (ADS)

    Bancal, Jean-Daniel; Gisin, Nicolas; Pironio, Stefano

    2010-09-01

    Finding all Bell inequalities for a given number of parties, measurement settings and measurement outcomes is in general a computationally hard task. We show that all Bell inequalities which are symmetric under the exchange of parties can be found by examining a symmetrized polytope which is simpler than the full Bell polytope. As an illustration of our method, we generate 238 885 new Bell inequalities and 1085 new Svetlichny inequalities. We find, in particular, facet inequalities for Bell experiments involving two parties and two measurement settings that are not of the Collins-Gisin-Linden-Massar-Popescu type.

  15. Top Quark Physics

    Microsoft Academic Search

    Thomas Teubner

    1999-01-01

    In this contribution I review the physics of top quarks at a future Linear Collider. Main emphasis is put on the process e+ e- --> t bar t close to threshold. Different physical observables, their sensitivity to the basic parameters and their theoretical prediction are discussed. Recent higher order calculations are shown to have a considerable impact on a precise

  16. Choosing a Top Ten.

    ERIC Educational Resources Information Center

    IUCN Bulletin, 1984

    1984-01-01

    Presents an annotated list of 34 animals and 32 plants which are candidates for a list of the top 10 endangered species. Also presents the criteria used to formulate these lists. They include the conservation value (urgency prominance, biological value) and operational considerations (such as cost factors) for each species. (JN)

  17. 100 Top Science Sites

    NSDL National Science Digital Library

    A simple but informative Web site, 100 Top Science Sites gives exactly that, along with very brief descriptions. Although nomination criteria were not given, several sites listed have been previously reviewed by the Internet Scout Project. A nice alternative to normal search engines, visitors can choose to receive notification emails for when the list changes or visit the site's chat room.

  18. Grandpa Top Model

    E-print Network

    Hacker, Randi

    2013-02-20

    clothes in a photo shoot cancelled. Grandpa Liu tried on a jacket and liked its style. So his granddaughter took photos of him in it and other items of clothing, posted them and China's next top model was created. Filial pietists accuse Ting of elder...

  19. Seismic mass Top electrode

    E-print Network

    Kraft, Michael

    of which provides loop transducer is described. A bulk-micromachined an accurate measure is that the micromachined, capacitive sensing element had only three connections (top and bottom electrodes and seismic mass domains, (Burstein and Kaiser, 1996). Usually, for an analogue, closed loop accelerometer the latter

  20. The Spectrum Top

    Microsoft Academic Search

    Dawson Turner

    1895-01-01

    PERHAPS some of your readers may be glad to learn that the curious phenomena of the spectrum top can be shown on a screen to a large audience. It is only necessary to paint the usual black lines and sector on a suitable disc of glass, and then to mount it in a revolving stage which can be rotated in

  1. Bumblebee preference for symmetrical flowers.

    PubMed

    Møller, A P

    1995-03-14

    Fluctuating asymmetry, which represents small random deviations from otherwise bilateral symmetry, is a measure of the phenotypic quality of individuals indicating the ability of controlled development under given environmental and genetic conditions. I tested whether floral symmetry reliably reflects phenotypic quality measured in terms of pollinator rewards and whether pollinators respond to floral symmetry in a series of observations and experiments on Epilobium angustifolium (Onagraceae). Lower petal asymmetry was negatively related to mean lower petal length, whereas asymmetry in leaf width was positively related to mean leaf width. Flowers visited by bumblebees were larger and more symmetrical than the nearest neighboring flower. This relationship between pollinator preference for large and symmetrical flowers was demonstrated to be causal in experiments in which the lower petals were manipulated symmetrically or asymmetrically. Nectar production was larger in symmetrical flowers, and this may explain the bumblebee preference for flower symmetry. Floral symmetry therefore reliably reflects nectar production and hence enhances pollen transport. Extensive embryo abortion has been documented in E. angustifolium and other outcrossing plant species. Floral fluctuating asymmetry, which reflects general developmental homeostasis, may explain such developmental selection in these plants. PMID:11607519

  2. On Symmetric Signatures Holographic Algorithms

    E-print Network

    Cai, Jin-Yi

    recently introduced a beautiful theory called holographic algorithms. Holographic algorithms are custom nodes. 10 #12;Linear bases transformations The first ingredient of the theory of holographic algorithmsOn Symmetric Signatures in Holographic Algorithms Jin-Yi Cai University of Wisconsin, Madison

  3. On Symmetrical Multilevel Diversity Coding

    Microsoft Academic Search

    Raymond W. Yeung; Zhen Zhang

    1999-01-01

    Symmetrical multilevel diversity coding with independent data streams has been studied by Roche et al. (1992), and the admissible coding rate region was determined for the case of three levels. In particular, it was shown that coding by superposition is optimal, which means that optimality can be achieved by very simple coding. However, it is very difficult to generalize their

  4. Additivity of the one-third power of the electron density in the hydrogen molecule--ion and hydrogen molecule

    SciTech Connect

    Lee, C.; Zdravkovic, S.; Parr, R.G. (Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599 (US))

    1990-02-01

    It is established that in the hydrogen molecule-ion and hydrogen molec the one-third power of the ground-state electron density is very well represented as a superposition of spherically symmetric densities on the two nuclei.(AIP)

  5. Additivity of the one-third power of the electron density in the hydrogen molecule-ion and hydrogen molecule

    Microsoft Academic Search

    Chengteh Lee; Slobodan Zdravkovic; Robert G. Parr

    1990-01-01

    It is established that in the hydrogen molecule?ion and hydrogen molec the one?third power of the ground?state electron density is very well represented as a superposition of spherically symmetric densities on the two nuclei.(AIP)

  6. Top-Down Mass Spectrometry: Recent Developments, Applications and Perspectives

    PubMed Central

    Cui, Weidong; Rohrs, Henry W.; Gross, Michael L.

    2012-01-01

    Top-down mass spectrometry is an emerging approach for the analysis of intact proteins. The term was coined as a contrast with the better-established, bottom-up strategy for analysis of peptide fragments derived from digestion, either enzymatically or chemically, of intact proteins. Although the term top-down originates from proteomics, it can also be applied to mass spectrometric analysis of intact large biomolecules that are constituents of protein assemblies or complexes. Traditionally, mass spectrometry has usually started with intact molecules, and in this regard, top-down approaches reflect the spirit of mass spectrometry. This article provides an overview of the methodologies in top-down mass spectrometry and then reviews applications covering protein posttranslational modifications, protein biophysics, DNAs/RNAs, and protein assemblies. Finally, challenges and future directions are discussed. PMID:21826297

  7. Theory of nuclear magnetic spin-rotational relaxation for asymmetric molecules

    Microsoft Academic Search

    James McConnell

    1988-01-01

    A stochastic differential equation study of nuclear magnetic relaxation by spin-rotational interactions was successfully completed for spherical, symmetric rotator and linear molecules. This theory has now been extended to asymmetric rotator molecules by first establishing the conditions under which such an extension is mathematically feasible and then investigating the consequences of accepting these conditions.

  8. Dynamics of Single-Molecule Rotations on Surfaces that Depend on Symmetry, Interactions, and Molecular Sizes

    E-print Network

    . The sulfur atom is strongly bound to the gold surface, and alkyl branches can rotate around it. Using STM on gold surfaces suggest that the size of the molecules, their flexibility, and steric repulsions as dialkylsulfides, are linear molecules with the sulfur atom in the middle connected to two symmetric alkyl chains

  9. Integrity bases for covariants of tetrahedral XY4 molecules. Application to the electric dipole moment surface

    E-print Network

    Recanati, Catherine

    with electric or magnetic properties, for example with the electric dipole moment surface. The symmetrized of the potential energy surface (PES) and of the electric dipole moment surface (EDMS) of the molecule under studyIntegrity bases for covariants of tetrahedral XY4 molecules. Application to the electric dipole

  10. Frustration in bilayers and topologies of liquid crystals of amphiphilic molecules

    E-print Network

    Paris-Sud XI, Université de

    683 Frustration in bilayers and topologies of liquid crystals of amphiphilic molecules J. F. Sadoc dicembre 1985) Résumé. - Les molécules amphiphiles construisent des films fluides symétriques, bicouches. - Amphiphilic molecules are well-known for their ability to build symmetric fluid films, or bilayers, most often

  11. Top physics results at CDF

    SciTech Connect

    Vickey, Trevor; /Illinois U., Urbana

    2005-05-01

    The most recent results on top quark physics at CDF are reported. Measurements of cross-section and mass are presented, and the status of single top quark production searches are discussed. The results obtained from probing various top quark properties are also presented.

  12. Curly Top Disease of Tomato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Curly top disease, caused by viruses in the genus, Curtovirus, has impacted western US agriculture for over a century; and is a significant threat to tomato production. The two most abundant curtovirus species today are Beet severe curly top virus (BSCTV) and Beet mild curly top virus (BMCTV) but ot...

  13. Top quark physics: Future Measurements

    SciTech Connect

    Frey, Raymond; Gerdes, David; Jaros, John; Vejcik, Steve; Berger, Edmond L.; Chivukula, R. Sekhar; Cuypers, Frank; Drell, Persis S.; Fero, Michael; Hadley, Nicholas; Han, Tao; Heinson, Ann P.; Knuteson, Bruce; Larios, Francisco; Miettinen, Hannu; Orr, Lynne H.; Peskin, Michael E.; Rizzo, Thomas; Sarid, Uri; Schmidt, Carl; Stelzer, Tim; Sullivan, Zack

    1996-12-31

    We discuss the study of the top quark at future experiments and machines. Top's large mass makes it a unique probe of physics at the natural electroweak scale. We emphasize measurements of the top quark's mass, width, and couplings, as well as searches for rare or nonstandard decays, and discuss the complementary roles played by hadron and lepton colliders.

  14. Symmetric Tensor Decomposition Description of Fermionic Many-Body Wavefunctions

    E-print Network

    Uemura, Wataru

    2012-01-01

    The configuration interaction (CI) is a versatile wavefunction theory for interacting fermions but it involves an extremely long CI series. Using a symmetric tensor decomposition (STD) method, we convert the CI series into a compact and numerically tractable form. The converted series encompasses the Hartree-Fock state in the first term and rapidly converges to the full-CI state, as numerically tested using small molecules. Provided that the length of the STD-CI series grows only moderately with the increasing complexity of the system, the new method will serve as one of the alternative variational methods to achieve full-CI with enhanced practicability.

  15. Introduction to Modern Cryptography Symmetric Encryption

    E-print Network

    Beimel, Amos

    Introduction to Modern Cryptography Benny Chor Symmetric Encryption: Stream & Block Ciphers Lecture of such G cannot be truly random! Introduction to Modern Cryptography Benny Chor Symmetric Encryption Symmetric Encryption: Stream & Block Ciphers #12;PRGs and OW Functions · Notice that if P=NP then neither

  16. Drawing Trees Symmetrically in Three Dimensions ?

    E-print Network

    Hong,Seokhee

    Drawing Trees Symmetrically in Three Dimensions ? Seok-Hee Hong and Peter Eades School. Symmetric graph drawing enables a clear understanding of the structure of the graph. Previous work on symmetric graph drawing has focused on two dimensions. Symmetry in three dimensions is much richer than

  17. Symmetric Walking Control: Invariance and Global Stability

    Microsoft Academic Search

    Sang-Ho Hyon; Takashi Emura

    2005-01-01

    This paper first presents a novel control strategy for periodic motion control based on a Hamiltonian system. Ac- cording to the strategy, hybrid symmetric orbits (ideal walking gaits) are explored using reversal symmetry of the Hamiltonian system. Then, an invariance controller, a Symmetric Walking Controller, is derived systematically to distribute the symmetric orbits densely throughout the entire phase space. Finally,

  18. [Biophysics of single molecules].

    PubMed

    Serdiuk, I N; Deriusheva, E I

    2011-01-01

    The modern methods of research of biological molecules whose application led to the development of a new field of science, biophysics of single molecules, are reviewed. The measurement of the characteristics of single molecules enables one to reveal their individual features, and it is just for this reason that much more information can be obtained from one molecule than from the entire ensample of molecules. The high sensitivity of the methods considered in detail makes it possible to come close to the solution of the basic problem of practical importance, namely, the determination of the nucleotide sequence of a single DNA molecule. PMID:22117447

  19. Spectral Norm of Symmetric Functions

    E-print Network

    Ada, Anil; Hatami, Hamed

    2012-01-01

    The spectral norm of a Boolean function $f:\\{0,1\\}^n \\to \\{-1,1\\}$ is the sum of the absolute values of its Fourier coefficients. This quantity provides useful upper and lower bounds on the complexity of a function in areas such as learning theory, circuit complexity, and communication complexity. In this paper, we give a combinatorial characterization for the spectral norm of symmetric functions. We show that the logarithm of the spectral norm is of the same order of magnitude as $r(f)\\log(n/r(f))$ where $r(f) = \\max\\{r_0,r_1\\}$, and $r_0$ and $r_1$ are the smallest integers less than $n/2$ such that $f(x)$ or $f(x) \\cdot parity(x)$ is constant for all $x$ with $\\sum x_i \\in [r_0, n-r_1]$. We mention some applications to the decision tree and communication complexity of symmetric functions.

  20. Inflation in a Symmetric Vacuum

    E-print Network

    Kevin Cahill

    2007-05-23

    If in a finite universe, the tree-level vacuum is a symmetric superposition of coherent states, in each of which the inflaton field assumes a different, energy-minimizing mean value (vev), then the resulting energy is positive and decreases exponentially as the volume of the universe increases. This effect can drive inflation when that volume is small and explain part of dark energy when it is big, but the effect is exceedingly tiny except at very early times.

  1. Diagram spaces and symmetric spectra

    Microsoft Academic Search

    Steffen Sagave; Christian Schlichtkrull

    2011-01-01

    We present a general homotopical analysis of structured diagram spaces and discuss the relation to symmetric spectra. The main motivating examples are the I-spaces, which are diagrams indexed by finite sets and injections, and J-spaces, which are diagrams indexed by the Grayson-Quillen construction on the category of finite sets and bijections. We show that the category of I-spaces provides a

  2. Symmetric informationally complete quantum measurements

    Microsoft Academic Search

    Joseph M. Renes; Robin Blume-Kohout; A. J. Scott; Carlton M. Caves

    2004-01-01

    We consider the existence in arbitrary finite dimensions d of a positive operator valued measure (POVM) comprised of d2 rank-one operators all of whose operator inner products are equal. Such a set is called a “symmetric, informationally complete” POVM (SIC–POVM) and is equivalent to a set of d2 equiangular lines in Cd. SIC–POVMs are relevant for quantum state tomography, quantum

  3. Greedy algorithm and symmetric matroids

    Microsoft Academic Search

    André Bouchet

    1987-01-01

    Symmetric matroids are set systems which are obtained, in some sense, by a weakening of the structure of a matroid. These\\u000a set systems are characterized by a greedy algorithm and they are suitable for dealing with autodual properties of matroids.\\u000a Applications are given to the eulerian tours of 4-regular graphs and the theory ofg-matroids.

  4. Symmetrization, quantum images and measurement

    E-print Network

    Fariel Shafee

    2005-07-11

    We argue that symmetrization of an incoming microstate with similar states in a sea of microstates contained in a macroscopic detector can produce an effective image, which does not contradict the no-cloning theorem, and such a combinatorial set can then be used with first passage random walk interactions suggested in an earlier work to give the right quantum mechanical weight for measured eigenvalues.

  5. Top quark physics at CDF

    SciTech Connect

    Potamianos, Karolos

    2011-12-01

    We present the recent results of top-quark physics using up to 6 fb{sup -1} of p{bar p} collisions analyzed by the CDF collaboration. The large number of top quark events analyzed, of the order of several thousands, allows stringent checks of the standard model predictions. Also, the top quark is widely believed to be a window to new physics. We present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.

  6. Top quark physics at CDF

    E-print Network

    Karolos Potamianos

    2011-12-01

    We present the recent results of top-quark physics using up to 6 fb$^{-1}$ of $p\\bar{p}$ collisions analyzed by the CDF collaboration. The large number of top quark events analyzed, of the order of several thousands, allows stringent checks of the standard model predictions. Also, the top quark is widely believed to be a window to new physics. We present the latest measurements of top quark intrinsic properties as well as direct searches for new physics in the top sector.

  7. Viscosity in spherically symmetric accretion

    E-print Network

    Arnab K. Ray

    2004-09-27

    The influence of viscosity on the flow behaviour in spherically symmetric accretion, has been studied here. The governing equation chosen has been the Navier-Stokes equation. It has been found that at least for the transonic solution, viscosity acts as a mechanism that detracts from the effectiveness of gravity. This has been conjectured to set up a limiting scale of length for gravity to bring about accretion, and the physical interpretation of such a length-scale has been compared with the conventional understanding of the so-called "accretion radius" for spherically symmetric accretion. For a perturbative presence of viscosity, it has also been pointed out that the critical points for inflows and outflows are not identical, which is a consequence of the fact that under the Navier-Stokes prescription, there is a breakdown of the invariance of the stationary inflow and outflow solutions -- an invariance that holds good under inviscid conditions. For inflows, the critical point gets shifted deeper within the gravitational potential well. Finally, a linear stability analysis of the stationary inflow solutions, under the influence of a perturbation that is in the nature of a standing wave, has indicated that the presence of viscosity induces greater stability in the system, than has been seen for the case of inviscid spherically symmetric inflows.

  8. Top quark pair production and top quark properties at CDF

    E-print Network

    Chang-Seong Moon

    2014-11-01

    We present the most recent measurements of top quark pairs production and top quark properties in proton-antiproton collisions with center-of-mass energy of 1.96 TeV using CDF II detector at the Tevatron. The combination of top pair production cross section measurements and the direct measurement of top quark width are reported. The test of Standard Model predictions for top quark decaying into $b$-quarks, performed by measuring the ratio $R$ between the top quark branching fraction to $b$-quark and the branching fraction to any type of down quark is shown. The extraction of the CKM matrix element $|V_{tb}|$ from the ratio $R$ is discussed. We also present the latest measurements on the forward-backward asymmetry ($A_{FB}$) in top anti-top quark production. With the full CDF Run II data set, the measurements are performed in top anti-top decaying to final states that contain one or two charged leptons (electrons or muons). In addition, we combine the results of the leptonic forward-backward asymmetry in $t\\bar t$ system between the two final states. All the results show deviations from the next-to-leading order (NLO) standard model (SM) calculation.

  9. Computing Z_top

    E-print Network

    Amir-Kian Kashani-Poor

    2014-08-06

    This is the text of my habilitation thesis defended at the \\'Ecole Normale Sup\\'erieure. The topological string presents an arena in which many features of string theory proper, such as the interplay between worldsheet and target space descriptions or open-closed duality, can be distilled into computational techniques which yield results beyond perturbation theory. In this thesis, I will summarize my research activity in this area. The presentation is organized around computations of the topological string partition function Z_top based on various perspectives on the topological string.

  10. Ultra-Cold Molecules

    Microsoft Academic Search

    A. Fioretti; M. Fazzi; M. Mazzoni; T. Ban; C. Gabbanini

    2004-01-01

    In this paper we overview recent results on the formation of translationally cold molecules. While there are some methods relying on direct cooling of molecules, we shall concentrate on the photoassociation technique that starts from laser-cooled atoms. The detection methods for the ultra-cold molecules will be presented together with a report on the trapping techniques. The treatment is mainly focused

  11. Modeling Symmetric Macromolecular Structures in Rosetta3

    PubMed Central

    DiMaio, Frank; Leaver-Fay, Andrew; Bradley, Phil; Baker, David; André, Ingemar

    2011-01-01

    Symmetric protein assemblies play important roles in many biochemical processes. However, the large size of such systems is challenging for traditional structure modeling methods. This paper describes the implementation of a general framework for modeling arbitrary symmetric systems in Rosetta3. We describe the various types of symmetries relevant to the study of protein structure that may be modeled using Rosetta's symmetric framework. We then describe how this symmetric framework is efficiently implemented within Rosetta, which restricts the conformational search space by sampling only symmetric degrees of freedom, and explicitly simulates only a subset of the interacting monomers. Finally, we describe structure prediction and design applications that utilize the Rosetta3 symmetric modeling capabilities, and provide a guide to running simulations on symmetric systems. PMID:21731614

  12. Patterns of energy levels and spectra for polyatomic molecules

    SciTech Connect

    Harter, W.G.

    1983-01-01

    Laser spectroscopy has revealed a remarkable intricacy in the rotational, vibrational, and electronic energy levels for polyatomic molecules. The infrared spectra of SF/sub 6/, CF/sub 4/, and related molecules contain several levels of structure on top of structure which resembles a fractal in some ways. The purpose of this article will be to exhibit some of this structure and introduce the simplest theoretical interpretations of it which are presently available.

  13. Top quark mass measurements

    SciTech Connect

    L. Cerrito

    2004-07-16

    Preliminary results on the measurement of the top quark mass at the Tevatron Collider are presented. In the dilepton decay channel, the CDF Collaboration measures m{sub t} = 175.0{sub -16.9}{sup +17.4}(stat.){+-}8.4(syst.) GeV/c{sup 2}, using a sample of {approx} 126 pb{sup -1} of proton-antiproton collision data at {radical}s = 1.96 TeV (Run II). In the lepton plus jets channel, the CDF Collaboration measures 177.5{sub -9.4}{sup +12.7}(stat.) {+-} 7.1(syst.) GeV/c{sup 2}, using a sample of {approx} 102 pb{sup -1} at {radical}s = 1.96 TeV. The D0 Collaboration has newly applied a likelihood technique to improve the analysis of {approx} 125 pb{sup -1} of proton-antiproton collisions at {radical}s = 1.8 TeV (Run I), with the result: m{sub t} = 180.1 {+-} 3.6(stat.) {+-}3.9(syst.) GeV/c{sup 2}. The latter is combined with all the measurements based on the data collected in Run I to yield the most recent and comprehensive experimental determination of the top quark mass: m{sub t} = 178.0 {+-} 2.7(stat.) {+-} 3.3(syst.) GeV/c{sup 2}.

  14. Hunting Mixed Top Squark Decays

    NASA Astrophysics Data System (ADS)

    Graesser, Michael L.; Shelton, Jessie

    2013-09-01

    We point out that, in the irreducible natural supersymmetric spectrum, top squarks have comparable branching fractions to chargino-bottom and neutralino-top final states in the vast bulk of parameter space, provided only that both decay modes are kinematically accessible. The total top squark pair branching fractions into tt¯+MET (MET=missingtransverseenergy) can therefore be reduced to O(50%), whereas bb¯+X branching fractions are typically much smaller, O(10%), thus limiting the reach of traditional top squark searches. We propose a new top squark search targeting the asymmetric final state t˜t˜*?t?0b¯?-+H.c., which can restore sensitivity to natural top squarks in the 7 and 8 TeV LHC runs. In addition, we present a new variable, topness, which efficiently suppresses the dominant top backgrounds to semileptonic top partner searches. We demonstrate the utility of topness in both our asymmetric search channel and traditional t˜t˜*?tt¯+MET searches and show that it matches or outperforms existing variables.

  15. Morphological Behavior Spanning the Symmetric AB Diblock and ABC Triblock Copolymer States

    NASA Astrophysics Data System (ADS)

    Bailey, Travis; Pham, Hoai; Bates, Frank

    2001-03-01

    A majority of studies involving ABC triblock copolymers have focused on the unique morphologies that particular molecules or blends express. However, unlike the phase behavior of AB diblocks, the progression of these morphologies as a function of composition is not very well understood. This work focuses on understanding the progression of morphologies expressed as molecules change composition from the symmetric AB diblock to the symmetric ABC triblock state. This type of transformation was achieved through systematic addition of PEO to a single symmetric PS-PI diblock copolymer (MW 18000g/mol), resulting in a series of 10 poly(styrene-b-isoprene-b-ethyleneoxide) triblock copolymers varying only the amount of PEO added. Final compositions ranged from 2.9 to 32.9symmetric) PEO by volume, the remaining volume always being divided equally between the PS and PI segments. The molecular weight of the parent diblock was chosen such that resulting triblocks could undergo order-disorder transitions at experimentally accessible temperatures over much of the composition range studied. The discussion will concentrate on the characterization of 6 morphologies observed between these 2 symmetric states and discuss some of the kinetic and directional (heating vs. cooling) characteristics of 2 thermally induced order-order transitions also observed. Finally, the effects of changing the connectivity of the PS and PI blocks on this morphological progression may also be considered.

  16. The top ten.

    PubMed

    Davis, C

    1985-10-01

    3 lists were compiled to answer the question of what countries have experienced the most population growth from World War II to the present. The 1st list includes the 10 countries which accounted for the largest gain in world population. The 2nd list shows the 10 countries with the highest growth rates of the 150 or so most populous countries in the world. The last list also shows countries ranked by growth rate but is limited to those with a current population of at least 10 million. To deal with the fact that some countries did not exist at 1 of the reference points, a set of estimates for 1940 provided a convenient starting point. China and India headed the list of countries ranked by absolute gains. They contributed half again as much growth as the next 8 nations combined. Altogether Asia, home to almost 60% of the world's population, captured 5 of the top 10 slots. The US and the USSR are the only developed countries on the list. The Soviet Union also presents the 1st case on the list of a country with a lower ranking in population gain (6th) than in absolute size in 1985 (3rd). Many of the population giants of 1940 (Japan, Great Britain, Germany, France, and Italy) are not on the list. Despite large base populations, their growth has been slow in the intervening years. All of the countries with the highest growth rates experienced over 3% annual average growth during the last 45 years: Kuwait, United Arab Emirates, Libya, Venezuela, Costa Rica, Kenya, Ivory Coast, Mexico, Honduras, and Syria. The influence of immigration is much in evidence in this list and explains otherwise unachievable rates of growth. The top 4 countries in annual rates of growth are all oil exporters. The top 3 countries in the 3rd list -- Venezuela, Kenya, and Mexico -- are carried over from the 2nd list, sharing the characteristics of rapid population growth and substantial base populations. The geographic mix of this list is notable. Asia, Africa, and Latin America each have at least 3 countries represented. Strikingly absent are countries from the developed world. Rapid growth occurs in countries of widely varying sizes. PMID:12267382

  17. Top physics results from CDF

    SciTech Connect

    Gomez, Gervasio; /Cantabria Inst. of Phys.

    2005-05-01

    The top quark is by far the most massive fundamental particle observed so far, and the study of its properties is interesting for several reasons ranging from its possible special role in electroweak symmetry breaking to its sensitivity to physics beyond the Standard Model. They present recent top physics results from CDF based on 160-320 pb{sup -1} of p{bar p} collision data at {radical}s = 1.96 TeV. The t{bar t} cross section and the top mass have been measured in different decay channels and using different methods. they have searched for evidence of single top production, setting upper limits on its production rate. Other results shown in this conference include studies of the polarization of W bosons from top decays, a search for charged Higgs decaying from top, and a search for additional heavy t' quarks.

  18. PT-Symmetric Talbot Effects

    E-print Network

    Ramezani, Hamidreza; Kovanis, V; Vitebskiy, I; Kottos, Tsampikos; 10.1103/PhysRevLett.109.033902

    2012-01-01

    We show that complex PT-symmetric photonic lattices can lead to a new class of self-imaging Talbot effects. For this to occur, we find that the input field pattern, has to respect specific periodicities which are dictated by the symmetries of the system. While at the spontaneous PT-symmetry breaking point, the image revivals occur at Talbot lengths governed by the characteristics of the passive lattice, at the exact phase it depends on the gain and loss parameter thus allowing one to control the imaging process.

  19. Spherically symmetric canonical quantum gravity

    NASA Astrophysics Data System (ADS)

    Brahma, Suddhasattwa

    2015-06-01

    Canonical quantization of spherically symmetric space-times is carried out, using real-valued densitized triads and extrinsic curvature components, with specific factor-ordering choices ensuring in an anomaly free quantum constraint algebra. Comparison with previous work [Nucl. Phys. B399, 211 (1993)] reveals that the resulting physical Hilbert space has the same form, although the basic canonical variables are different in the two approaches. As an extension, holonomy modifications from loop quantum gravity are shown to deform the Dirac space-time algebra, while going beyond "effective" calculations.

  20. PT-symmetric optical lattices

    SciTech Connect

    Makris, Konstantinos G.; El-Ganainy, Ramy; Christodoulides, Demetrios N.; Musslimani, Z. H. [College of Optics/CREOL, University of Central Florida, Orlando, Florida 32816 (United States); Department of Mathematics, Florida State University Tallahassee, Florida 32306-4510 (United States)

    2010-06-15

    The basic properties of Floquet-Bloch (FB) modes in parity-time (PT)-symmetric optical lattices are examined in detail. Due to the parity-time symmetry of such complex periodic potentials, the corresponding FB modes are skewed (nonorthogonal) and nonreciprocal. The conjugate pairs of these FB modes are obtained by reflecting both the spatial coordinate and the Bloch momentum number itself. The orthogonality conditions are analytically derived for a single cell, for both a finite and an infinite lattice. Some of the peculiarities associated with the diffraction dynamics in PT lattices such as nonreciprocity, power oscillations, and phase dislocations, are also examined.

  1. Symmetric spaces of exceptional groups

    SciTech Connect

    Boya, L. J., E-mail: luisjo@unizar.e [Universidad de Zaragoza, Departamento de Fisica Teorica (Spain)

    2010-02-15

    We address the problem of the reasons for the existence of 12 symmetric spaces with the exceptional Lie groups. The 1 + 2 cases for G{sub 2} and F{sub 4}, respectively, are easily explained from the octonionic nature of these groups. The 4 + 3 + 2 cases on the E{sub 6,7,8} series require the magic square of Freudenthal and, for the split case, an appeal to the supergravity chain in 5, 4, and 3 space-time dimensions.

  2. Single Top production at LHC

    E-print Network

    M. Mohammadi Najafabadi

    2006-05-15

    The Production of single top quarks at LHC provides an ideal framework to investigate the properties of electroweak interaction, in particular of the {\\it tWb} coupling. Moreover, single top is a powerful mean to identify physics beyond the standard model. All three different production mechanisms of single top are expected to be observed at LHC. Recent studies from ATLAS and CMS are presented.

  3. Properties of the Top Quark

    E-print Network

    Daniel Wicke

    2011-09-16

    The top quark was discoverd at the CDF and D0 experiments in 1995. As the partner of the bottom quark its properties within the Standard Model are fully defined. Only the mass is a free parameter. The measurement of the top quark mass and the verification of the expected properties have been an important topic of experimental top quark physics since. In this review the recent results on top quark properties obtained by the Tevatron experiments CDF and D0 are summarised. At the advent of the LHC special emphasis is given to the basic measurement methods and the dominating systematic uncertainties.

  4. Boosted top: experimental tools overview

    E-print Network

    Emanuele Usai; for the ATLAS; CMS Collaborations

    2015-01-05

    An overview of tools and methods for the reconstruction of high-boost top quark decays at the LHC is given in this report. The focus is on hadronic decays, in particular an overview of the current status of top quark taggers in physics analyses is presented. The most widely used jet substructure techniques, normally used in combination with top quark taggers, are reviewed. Special techniques to treat pileup in large cone jets are described, along with a comparison of the performance of several boosted top quark reconstruction techniques.

  5. Resolution by Unassisted Top3 Points to Template Switch Recombination Intermediates during DNA Replication*

    PubMed Central

    Glineburg, M. Rebecca; Chavez, Alejandro; Agrawal, Vishesh; Brill, Steven J.; Johnson, F. Brad

    2013-01-01

    The evolutionarily conserved Sgs1/Top3/Rmi1 (STR) complex plays vital roles in DNA replication and repair. One crucial activity of the complex is dissolution of toxic X-shaped recombination intermediates that accumulate during replication of damaged DNA. However, despite several years of study the nature of these X-shaped molecules remains debated. Here we use genetic approaches and two-dimensional gel electrophoresis of genomic DNA to show that Top3, unassisted by Sgs1 and Rmi1, has modest capacities to provide resistance to MMS and to resolve recombination-dependent X-shaped molecules. The X-shaped molecules have structural properties consistent with hemicatenane-related template switch recombination intermediates (Rec-Xs) but not Holliday junction (HJ) intermediates. Consistent with these findings, we demonstrate that purified Top3 can resolve a synthetic Rec-X but not a synthetic double HJ in vitro. We also find that unassisted Top3 does not affect crossing over during double strand break repair, which is known to involve double HJ intermediates, confirming that unassisted Top3 activities are restricted to substrates that are distinct from HJs. These data help illuminate the nature of the X-shaped molecules that accumulate during replication of damaged DNA templates, and also clarify the roles played by Top3 and the STR complex as a whole during the resolution of replication-associated recombination intermediates. PMID:24100144

  6. The importance of new molecules in selective perfumery.

    PubMed

    Roucel, Maurice; Grau, Fanny

    2014-10-01

    Perfumery can only evolve thanks to new ingredients. We highlight herein some key molecules and their use in 'Selective Perfumery': the violet odorant undecavertol, the floral nerolione and coumarone, the gourmand cappuccino levistamel, the sandalwood notes Sandranol(®) or Bacdanol(®) , the fruity top note Magnolia Flower oil, and finally the woody ambery Ambrocenide(®) . PMID:25329780

  7. Pinning down top dipole moments with ultraboosted tops

    NASA Astrophysics Data System (ADS)

    Aguilar-Saavedra, Juan A.; Fuks, Benjamin; Mangano, Michelangelo L.

    2015-05-01

    We investigate existing and future hadron-collider constraints on the top dipole chromomagnetic and chromoelectric moments, two quantities that are expected to be modified in the presence of new physics. We focus first on recent measurements of the inclusive top pair production cross section at the Tevatron and at the Large Hadron Collider. We then analyze the role of top-antitop events produced at very large invariant masses, in the context of the forthcoming 13-14 TeV runs of the LHC, and at a future 100 TeV proton-proton collider. In this latter case, the selection of semileptonic decays to hard muons allows to tag top quarks boosted to the multi-TeV regime, strongly reducing the QCD backgrounds and leading to a significant improvement in the sensitivity to anomalous top couplings.

  8. Risk aversion in symmetric and asymmetric contests

    Microsoft Academic Search

    Richard Cornes; Roger Hartley

    2008-01-01

    We analyze existence, uniqueness and properties of equilibria in incompletely discriminating Tullock contests with logistic\\u000a contest success functions, when contestants are risk averse. We prove that a Nash equilibrium for such a contest exists, but\\u000a give an example of a symmetric contest with both symmetric and asymmetric equilibria, showing that risk aversion may lead\\u000a to multiple equilibria. Symmetric contests have

  9. Probabilistic cloning of three symmetric states

    SciTech Connect

    Jimenez, O. [Center for Optics and Photonics, Departamento de Fisica, Universidad de Concepcion, Casilla 4016, Concepcion (Chile); Departamento de Fisica, Facultad de Ciencias Basicas, Universidad de Antofagasta, Casilla 170, Antofagasta (Chile); Bergou, J. [Department of Physics, Hunter College, City University of New York, 695 Park Avenue, New York, New York 10021 (United States); Delgado, A. [Center for Optics and Photonics, Departamento de Fisica, Universidad de Concepcion, Casilla 4016, Concepcion (Chile); Departamento de Fisica, Universidad de Concepcion, Casilla 160-C, Concepcion (Chile)

    2010-12-15

    We study the probabilistic cloning of three symmetric states. These states are defined by a single complex quantity, the inner product among them. We show that three different probabilistic cloning machines are necessary to optimally clone all possible families of three symmetric states. We also show that the optimal cloning probability of generating M copies out of one original can be cast as the quotient between the success probability of unambiguously discriminating one and M copies of symmetric states.

  10. Electrical readouts of single and few molecule systems in metal-molecule-metal device structures.

    PubMed

    Mahapatro, Ajit K; Janes, David B

    2007-06-01

    Electrical conduction through molecular junctions are measured in different local environments through two test beds that are ideal for single/few molecule and molecular monolayer systems. A technique has been developed to realize Au films with approximately 1.5 A surface roughness comparable to the best available techniques and suitable for formation of patterned device structures. The technique utilizes room temperature e-beam evaporated Au films over oxidized Si substrates silanized with (3-mercaptopropyl)trimethoxysilane (MPTMS). The lateral (single/few molecule) and vertical (many molecules) device structures are both enabled by the process for realizing ultraflat Au layer. Lateral metal-molecule-metal (M-M-M) device structures are fabricated by forming pairs of Au electrodes with nanometer separation (nano-gap) through an electromigration-induced break-junction (EIBJ) technique at room temperature and conductivity measurements are carried out for dithiol functionalized single molecules. We have used the flat Au layer (using the current technique) as the bottom contact in vertical M-M-M device structures. Here, molecular self-assembly are formed on the Au surface, and patterned (20 x 20 microm2) top Au contacts were successfully transferred on to the device using a stamping technique (where the Au is deposited on a polydimethylsiloxane (PDMS) pad and following a physical contact on the thiolated Au layer). The single molecular property of XYL, a highly conductive molecule and many molecular property of HS-C9-SH, an insulating molecule in its molecular monolayer form are measured. Observation of enhanced conduction following molecular deposition, and comparison of conductance-voltage characteristics to those predicted theoretically, confirms the success of trapping single/few molecules in the nano-gap. The observed approximately 10(2) less conductance through the molecular monolayer of HS-C9-SH compared to the estimation of a linear sum of single molecule conductances over large area indicate that either all the molecules are not in physical contact with the top stamping electrode or electrode-molecule coupling has a less broadening in presence of it own environment or both. PMID:17655006

  11. Detection of chiral molecules

    NASA Astrophysics Data System (ADS)

    Patterson, David

    2014-05-01

    Recent years have seen an enormous growth of rich physics performed with cold samples of diatomic molecules, as well as impressive demonstrations of techniques to cool polyatomic molecules containing several (~7) atoms. Here we present progress in our methods to produce cold, dense, slow moving samples of molecules of many (>20) atoms from cryogenic buffer gas cells. The ability to produce cold, slow samples of such molecules opens up a host of potential research paths, including ultra-high precision spectroscopy, searches for changes in fundamental constants, and a rich set of experiments in the complex, low-decoherence Hilbert space spanned by the rotational and hyperfine states of such molecules. As an early demonstration of the rich physics offered in such systems, recent results demonstrating chirality-sensitive microwave spectroscopy of cold molecules will be presented.

  12. Amidothionophosphates: Novel Antioxidant Molecules

    Microsoft Academic Search

    Oren Tirosh; Yehoshua Katzhendler; Yechezkel Barenholz; Isaac Ginsburg; Ron Kohen

    1996-01-01

    This work describes the synthesis and characterization of a new family of antioxidants. The molecules have the same active group, but different oil-to-water and octanol-to-water partition coefficients due to different substituents. Three new molecules were synthesized based on the chemical structure of the primary amide attached to a thiophosphate group forming an amidothionophosphate. The amidothionophosphate molecules were exposed to the

  13. Symmetric and Asymmetric Encryption GUSTAVUS J. SIMMONS

    E-print Network

    Lee, Ruby B.

    Symmetric and Asymmetric Encryption GUSTAVUS J. SIMMONS Sandm Laboratories, Albuquerque, New Mexico;306 · Gustavus J. Simmons CONTENTS INTRODUCTION 1 CLASSICAL CRYPTOGRAPHY 2 READER'S GUIDE 3 THE COMMUNICATIONS

  14. Photochemistry of interstellar molecules

    NASA Technical Reports Server (NTRS)

    Stief, L. J.

    1973-01-01

    The role of photochemistry in determining the lifetime of interstellar molecules is considered. The probability of photodecomposition depends on three factors, including the absorption cross section, the quantum yield or probability of dissociation following photon absorption, and the interstellar radiation field. A more detailed discussion of the photochemistry of five molecules is presented, giving attention to carbonyl sulfide, methyl acetylene, nitric oxide, acetylene, and benzene. Lifetimes of interstellar molecules in unobscured regions are in the range from 5 to 100 years. It is concluded that polyatomic molecules can exist only in dense clouds which protect them from the full interstellar radiation field.

  15. Precision on the top mass

    E-print Network

    Stefan Weinzierl

    2015-05-04

    In this talk I will focus on theoretical issues related to high precision determinations of the top mass. Several mass definitions are reviewed and their respective advantages and disadvantages are discussed. Precision determinations of the top mass will require a short-distance mass definition. I will summarise current work in this direction.

  16. Identification of Top Performing Economies

    Microsoft Academic Search

    Kumar Akhilesh S; Ravindra H. Dholakia

    Using seven indicators of the economic performance of 187 countries, the paper identifies the top 50 performers during the decades of 1981-90 and 1991-2000. Five of these indicators are the trend rates of growth over a decade in imports, FDI, capital formation, per capita income and forex reserves. Average inflation rate and HDI are the remaining indicators. Comparison of top

  17. Top-ophilia Chris Quigg

    E-print Network

    Quigg, Chris

    was a top and anti- top, it was just so amazing that people had made a device that could see, in real space;Figure 1: Something rates the experimental sheep from the goats-- and I guess they are still separating

  18. Assessment techniques for top executives

    Microsoft Academic Search

    Kathleen A. Guinn

    1996-01-01

    Presents barriers and benefits to top executive assessment. Discusses a range of techniques for top executive assessment and feedback. Explores pros and cons of psychological testing, individual competence assessment conducted by an external consultant and multi-source assessment feedback techniques. Emphasizes the critical importance of selecting the right behaviours for assessing executive behaviour. Presents reliable approaches to identifying the right behaviours

  19. Symmetric nested complexes of fullerenes.

    PubMed

    Mar, Naveicy; Sansores, Luis Enrique; Muhl, Stephen; Ramos, Estrella; Salcedo, Roberto

    2015-04-01

    Large fullerenes such as C180 and C116 can be used as hosts for other molecules of the same family. Based on this idea, two complexes were designed, one in which C180 accepts a C60 molecule as a guest and the other in which C20 was placed inside C116. The behavior of these new assemblies was closer to that of a large endohedral complex rather than onion-like. There were marked differences between the systems. In the first system, there was minor interaction between the two cages but the association resulted in a more stable thermodynamic state. In the second system, there was strong electronic interchange between the cages, and the thermodynamic results suggest that such a combination might be useful for forming stable C20. PMID:25823391

  20. Symmetrical mixtures in external fields

    NASA Astrophysics Data System (ADS)

    Materniak, S.; Patrykiejew, A.

    2013-07-01

    We have studied the behavior of symmetrical binary mixtures of Lennard-Jones particles in contact with strongly adsorbing walls using Monte Carlo simulation methods in the grand canonical and semi-grand canonical ensembles. Two types of the surface potential have been applied. The first depends on the distance from the surface only, while the second involves periodic modulations in the directions parallel to the wall. In the latter case, it has been assumed that the solid substrate is a fcc crystal with the surface being the (100) face. We have considered the systems in which the surface potential is strong enough to induce the layer-by-layer adsorption at low temperatures and discussed the interplay between the demixing transition and the structure of thin films for several systems characterized by different parameters describing the interactions in the system.

  1. Symmetrical mixtures in external fields.

    PubMed

    Materniak, S; Patrykiejew, A

    2013-07-01

    We have studied the behavior of symmetrical binary mixtures of Lennard-Jones particles in contact with strongly adsorbing walls using Monte Carlo simulation methods in the grand canonical and semi-grand canonical ensembles. Two types of the surface potential have been applied. The first depends on the distance from the surface only, while the second involves periodic modulations in the directions parallel to the wall. In the latter case, it has been assumed that the solid substrate is a fcc crystal with the surface being the (100) face. We have considered the systems in which the surface potential is strong enough to induce the layer-by-layer adsorption at low temperatures and discussed the interplay between the demixing transition and the structure of thin films for several systems characterized by different parameters describing the interactions in the system. PMID:23822318

  2. A Minimally Symmetric Higgs Boson

    E-print Network

    Ian Low

    2015-06-10

    Models addressing the naturalness of a light Higgs boson typically employ symmetries, either bosonic or fermionic, to stabilize the Higgs mass. We consider a setup with the minimal amount of symmetries: four shift symmetries acting on the four components of the Higgs doublet, subject to the constraints of linearly realized SU(2)xU(1) electroweak symmetry. Up to terms that explicitly violate the shift symmetries, the effective lagrangian can be derived, irrespective of the spontaneously broken group G in the ultraviolet, and is universal in all models where the Higgs arises as a pseudo-Nambu-Goldstone boson (PNGB). Very high energy scatterings of vector bosons could provide smoking gun signals of a minimally symmetric Higgs boson.

  3. Symmetric differential capacitive pressure sensor

    NASA Astrophysics Data System (ADS)

    Peters, Randall D.

    1993-08-01

    Differential capacitive sensors are common to pressure gauges. Previous sensors of the bridge type have utilized only two variable (active) components, resulting in a half-bridge electrical equivalent circuit. There are numerous advantages of a symmetric full bridge, using four active components. The symmetry improves linearity and increases signal to noise ratio, especially when supported by electronics based on synchronous detection. Another advantage of symmetry is invariance to scaling, through immunity to stray capacitance. This feature is especially important in relationship to the current trend toward micro-electro-mechanical systems. A crude, inexpensive, macroscopic prototype of the present design was built with attention to high sensitivity. Constructed with a thin aluminized Mylar diaphragm, this device can readily resolve pressure changes smaller than 10-2 Pa.

  4. A Minimally Symmetric Higgs Boson

    E-print Network

    Ian Low

    2014-12-05

    Models addressing the naturalness of a light Higgs boson typically employ symmetries, either bosonic or fermionic, to stabilize the Higgs mass. We consider a setup with the minimal amount of symmetries: four shift symmetries acting on the four components of the Higgs doublet, subject to the constraints of linearly realized SU(2)xU(1) electroweak symmetry. Up to terms that explicitly violate the shift symmetries, the effective lagrangian can be derived, irrespective of the spontaneously broken group G in the ultraviolet, and is universal in all models where the Higgs arises as a pseudo-Nambu-Goldstone boson (PNGB). Very high energy scatterings of vector bosons could provide smoking gun signals of a minimally symmetric Higgs boson.

  5. IEEE COMMUNICATIONS LETTERS 1 Symmetric and a-symmetric Slepian-Wolf codes

    E-print Network

    Dragotti, Pier Luigi

    IEEE COMMUNICATIONS LETTERS 1 Symmetric and a-symmetric Slepian-Wolf codes with systematic and non channel codes that can achieve any point of the Slepian-Wolf achievable rate region. Our approach is very coding, Slepian-Wolf theo- rem, symmetric encoding, linear channel codes. I. INTRODUCTION THE Slepian-Wolf

  6. PHYS 242 Problem set 4 1. A simple example of a molecule with an electric dipole moment is HCl, which has

    E-print Network

    Lovejoy, Shaun

    dielectric constant of 1.5. The free charge density on the top plate is and on the bottom plate is ­. a is filled with two slabs of linear dielectric material, one on top of the other. Each slab had thickness s electrons to form a spherically symmetrical negative charge centred on the Cl nucleus. How would

  7. Enzymatic DNA molecules

    NASA Technical Reports Server (NTRS)

    Joyce, Gerald F. (Inventor); Breaker, Ronald R. (Inventor)

    1998-01-01

    The present invention discloses deoxyribonucleic acid enzymes--catalytic or enzymatic DNA molecules--capable of cleaving nucleic acid sequences or molecules, particularly RNA, in a site-specific manner, as well as compositions including same. Methods of making and using the disclosed enzymes and compositions are also disclosed.

  8. Molecules in Living Systems

    NSDL National Science Digital Library

    2012-06-19

    This lesson explains the difference between molecules in living systems and inanimate objects. In living systems, atoms and molecules are organized to a much greater degree and provide the structure of the organism. Lipids, carbohydrates, proteins, and nucleic acids are also discussed.

  9. Status of the top quark: Top production cross section and top properties

    SciTech Connect

    Boisvert, V.; /Rochester U.

    2006-08-01

    This report describes the latest cross section and property measurements associated with the top quark at the Tevatron Run II. The largest data sample used is 760 pb{sup -1} of integrated luminosity. Due to its large mass, the top quark might be involved in the process of electroweak symmetry breaking, making it a useful probe for signs of new physics.

  10. Dissociation of the Hydrogen Molecule–Ion from the Viewpoint of the Integral Hellmann–Feynman Formula

    Microsoft Academic Search

    MICHAEL T. MARRONt; Robert G. Parr

    1970-01-01

    The dissociation energy of the hydrogen molecule–ion is computed and analyzed by means of the integral Hellmann–Feynman theorem. The molecule is considered to dissociate either unsymmetrically by the removal of one of the nuclei to infinity or symmetrically by the simultaneous removal of both nuclei to infinity. The energy change is computed for each path and compared with the difference

  11. The Magic Square and Symmetric Compositions II

    Microsoft Academic Search

    Alberto Elduque

    2005-01-01

    The construction of Freudenthal's Magic Square, which contains the exceptional simple Lie algebras, in terms of symmetric composition algebras is further developed here. The para-Hurwitz algebras, which form a subclass of the symmetric composition algebras, will be defined, in the split case, in terms of the natural two dimensional module for the simple Lie algebra sl(2). As a consequence, it

  12. Results on rotation symmetric bent functions

    Microsoft Academic Search

    Deepak Kumar Dalai; Subhamoy Maitra; Sumanta Sarkar

    2009-01-01

    In this paper we analyze the combinatorial properties related to the Walsh spectra of rotation symmetric Boolean functions on even number of variables. These results are then applied in studying rotation symmetric bent functions. 2n n ) than the total space of Boolean functions (22 n ) and the set contains functions with very good cryptographic properties. It has been

  13. EM Algorithm for Symmetric Causal Independence Models

    Microsoft Academic Search

    Rasa Jurgelenaite; Tom Heskes

    2006-01-01

    Causal independence modelling is a well-known method both for reducing the size of probability tables and for explaining the underly- ing mechanisms in Bayesian networks. In this paper, we present the EM algorithm to learn the parameters in causal independence models based on the symmetric Boolean function. The developed algorithm enables us to assess the practical usefulness of the symmetric

  14. Error correction and symmetrization in quantum computers

    Microsoft Academic Search

    Asher Peres

    1996-01-01

    Errors in quantum computers are of two kinds: sudden perturbations to isolated qubits, and slow random drifts of all the qubits. The latter may be reduced, but not eliminated, by means of symmetrization, namely by using many replicas of the computer, and forcing their joint quantum state to be completely symmetric. On the other hand, isolated errors can be corrected

  15. Detecting Symmetry and Symmetric Constellations of Features

    Microsoft Academic Search

    Gareth Loyand; Jan-olof Eklundh

    2006-01-01

    A novel and efficient method is presented for grouping feature points on the basis of their underlying symmetry and characterising the symmetries present in an image. We show how symmetric pairs of features can be efficiently detected, how the symmetry bonding each pair is extracted and evaluated, and how these can be grouped into symmetric constellations that specify the domi-

  16. Controlling electric, magnetic, and chiral dipolar emission with PT-symmetric potentials

    NASA Astrophysics Data System (ADS)

    Alaeian, Hadiseh; Dionne, Jennifer A.

    2015-06-01

    We investigate the effect of parity-time (PT) symmetric optical potentials on the radiation of achiral and chiral dipole sources. Two properties unique to PT-symmetric potentials are observed. First, the dipole can be tuned to behave as a strong optical emitter or absorber based on the non-Hermiticity parameter and the dipole location. Second, exceptional points give rise to new system resonances that lead to orders-of-magnitude enhancements in the dipolar emitted or absorbed power. Utilizing these properties, we show that enantiomers of chiral molecules near PT-symmetric metamaterials exhibit a 4.5-fold difference in their emitted power and decay rate. The results of this work could enable new atom-cavity interactions for quantum optics, as well as all-optical enantioselective separation.

  17. Turbulence near thunderstorm tops

    NASA Technical Reports Server (NTRS)

    Lester, Peter F.

    1993-01-01

    For several years, scientists at San Jose State University, NASA-Ames, and the University of Arizona have carried out cooperative research programs to understand the causes and effects of severe turbulence. The primary sources of data for this work are Digital Flight Data Recorder (DFDR) tapes from airliners that have been involved in turbulence incidents. A significant result of the analysis of these data has been the identification and quantification of the turbulence causes. Turbulence signatures include breaking Kelvin-Helmholtz waves, large amplitude mountain lee waves, turbulence in and around thunderstorms, and maneuvering. The requirements that must be met for a turbulence incident to be included in the NASA study are rather straightforward: (1) severe or greater turbulence must have been reported (usually with passenger injuries) and (2) the flight data tapes must be available. Despite these rather general criteria, and the fact that our cases are drawn from a wide geographical area over the U.S. and the Atlantic Ocean, we have found an interesting bias in our sample. Of 12 cases at cruise altitude, four were definitely associated with thunderstorms and two are suspected thunderstorm cases. The others were due to mountain waves, CAT, high level windshear/maneuvering, or to causes not yet determined. Although our sample is small, these numbers have raised several questions, not the least of which are: How pervasive is the problem of aircraft encounters with severe turbulence in or near thunderstorm tops (TNTT)? Given the available visible and radar evidence of thunderstorms, Why do such incidents occur? Can anything be done to allevaite the problem? This paper outlines some very preliminary efforts to answer these questions. In the following sections, physical and statistical characteristics of TNTT are discussed (Section 2), TNTT causes are summarized (Section 3), current recommendations for TNTT avoidance are reviewed (Section 4), and some suggestions to ameliorate the problem are given (Section 5).

  18. Affine Stanley symmetric functions for classical types

    E-print Network

    Pon, Steven

    2011-01-01

    We introduce affine Stanley symmetric functions for the special orthogonal groups, a class of symmetric functions that model the cohomology of the affine Grassmannian, continuing the work of Lam and Lam, Schilling, and Shimozono on the special linear and symplectic groups, respectively. For the odd orthogonal groups, a Hopf-algebra isomorphism is given, identifying (co)homology Schubert classes with symmetric functions. For the even orthogonal groups, we conjecture an approximate model of (co)homology via symmetric functions. In the process, we develop type B and type D non-commutative k-Schur functions as elements of the nilCoxeter algebra that model homology of the affine Grassmannian. Additionally, Pieri rules for multiplication by special Schubert classes in homology are given in both cases. Finally, we present a type-free interpretation of Pieri factors, used in the definition of noncommutative k-Schur functions or affine Stanley symmetric functions for any classical type.

  19. Top coat or no top coat for immersion lithography?

    NASA Astrophysics Data System (ADS)

    Stepanenko, N.; Kim, Hyun-Woo; Kishimura, S.; Van Den Heuvel, D.; Vandenbroeck, N.; Kocsis, M.; Foubert, P.; Maenhoudt, M.; Ercken, M.; Van Roey, F.; Gronheid, R.; Pollentier, I.; Vangoidsenhoven, D.; Delvaux, C.; Baerts, C.; O'Brien, S.; Fyen, W.; Wells, G.

    2006-03-01

    Since the moment immersion lithography appeared in the roadmaps of IC manufacturers, the question whether to use top coats has become one of the important topics for discussions. The top coats used in immersion lithography have proved to serve as good protectors from leaching of the resist components (PAGs, bases) into the water. However their application complicates the process and may lead to two side effects. First, top coats can affect the process window and resist profile depending on the material's refractive index, thickness, acidity, chemical interaction with the resist and the soaking time. Second, the top coat application may increase the total amount of defects on the wafer. Having an immersion resist which could work without the top coat would be a preferable solution. Still, it is quite challenging to make such a resist as direct water/resist interaction may also result in process window changes, CD variations, generation of additional defects. We have performed a systematic evaluation of a large number of immersion resist and top coat combinations, using the ASML XT:1250Di scanner at IMEC. The samples for the experiments were provided by all the leading resist and top coat suppliers. Particular attention was paid to how the resist and top coat materials from different vendors interacted with each other. Among the factors which could influence the total amount of defects or CD variations on the wafer were: the material's dynamic contact angle and its interaction with the scanner stage speed, top coat thickness and intermixing layer formation, water uptake and leaching. We have examined the importance of all mentioned factors, using such analytical techniques as Resist Development Analyser (RDA), Quartz Crystal Microbalance (QCM), Mass Spectroscopy (MS) and scatterometry. We have also evaluated the influence of the pre- and pos- exposure rinse processes on the defectivity. In this paper we will present the data on imaging and defectivity performance of the resists with and without the use of top coats. So far we can conclude that top coat/resist approach used in immersion lithography needs some more improvements (i.e. process, materials properties) in order to be implemented in high volume manufacturing.

  20. Light outcoupling efficiency of top-emitting organic light-emitting diodes

    Microsoft Academic Search

    L. H. Smith; J. A. E. Wasey; W. L. Barnes

    2004-01-01

    We report results obtained from modeling the light outcoupling efficiency of top–emitting organic light-emitting diode (OLED) structures and compare them with results from conventional substrate-emitting structures. We investigate two types of emissive material, small molecule and conjugated polymers, and study three different cathode materials; aluminum, silver, and calcium. We show that top-emitting OLEDs may have outcoupling efficiencies comparable to their

  1. Light outcoupling efficiency of top-emitting organic light-emitting diodes

    Microsoft Academic Search

    L. H. Smith; J. A. E. Wasey; W. L. Barnes

    2004-01-01

    We report results obtained from modeling the light outcoupling efficiency of top-emitting organic light-emitting diode (OLED) structures and compare them with results from conventional substrate-emitting structures. We investigate two types of emissive material, small molecule and conjugated polymers, and study three different cathode materials; aluminum, silver, and calcium. We show that top-emitting OLEDs may have outcoupling efficiencies comparable to their

  2. Metal-molecule contacts and charge transport across monomolecular layers: measurement and theory.

    PubMed

    Kushmerick, J G; Holt, D B; Yang, J C; Naciri, J; Moore, M H; Shashidhar, R

    2002-08-19

    Charge transport studies across molecular length scales under symmetric and asymmetric metal-molecule contact conditions using a simple crossed-wire tunnel junction technique are presented. It is demonstrated that oligo(phenylene ethynylene), a conjugated organic molecule, acts like a molecular wire under symmetric contact conditions, but exhibits characteristics of a molecular diode when the connections are asymmetric. To understand this behavior, we have calculated current-voltage (I-V) characteristics using extended Huckel theory coupled with a Green's function approach. The experimentally observed I-V characteristics are in excellent qualitative agreement with the theory. PMID:12190491

  3. Single-top production at hadron colliders

    E-print Network

    Patrick Motylinski

    2011-12-20

    We review the recent theoretical progress in single-top physics at hadron colliders. Apart from single-top production within the Standard Model we treat certain aspects of single-top production in beyond Standard Model scenarios.

  4. Engineering Statistics From "Engineering Statistics" , Top &

    E-print Network

    Kovintavewat, Piya

    Engineering Statistics From "Engineering Statistics" , Top & Wiley, Prapaisri & Pongchanun 2 From "Engineering Statistics" , Top & Wiley, Prapaisri & Pongchanun 3 " "(Sample) (Sampling) ""(Population) " "(Statistics) ""(Parameter) From "Engineering Statistics" , Top & Wiley, Prapaisri

  5. Single top quark from technipion production

    E-print Network

    Baringer, Philip S.

    1997-09-01

    We investigate the contribution of technicolor mechanisms to the production of single top quarks at hadron colliders. Technipions with a mass larger than the top quark mass will decay predominantly to a top quark plus a bottom antiquark. We...

  6. The Molecule Pages database.

    PubMed

    Saunders, Brian; Lyon, Stephen; Day, Matthew; Riley, Brenda; Chenette, Emily; Subramaniam, Shankar; Vadivelu, Ilango

    2008-01-01

    The UCSD-Nature Signaling Gateway Molecule Pages (http://www.signaling-gateway.org/molecule) provides essential information on more than 3800 mammalian proteins involved in cellular signaling. The Molecule Pages contain expert-authored and peer-reviewed information based on the published literature, complemented by regularly updated information derived from public data source references and sequence analysis. The expert-authored data includes both a full-text review about the molecule, with citations, and highly structured data for bioinformatics interrogation, including information on protein interactions and states, transitions between states and protein function. The expert-authored pages are anonymously peer reviewed by the Nature Publishing Group. The Molecule Pages data is present in an object-relational database format and is freely accessible to the authors, the reviewers and the public from a web browser that serves as a presentation layer. The Molecule Pages are supported by several applications that along with the database and the interfaces form a multi-tier architecture. The Molecule Pages and the Signaling Gateway are routinely accessed by a very large research community. PMID:17965093

  7. Observation of ultralong-range Rydberg molecules.

    PubMed

    Bendkowsky, Vera; Butscher, Björn; Nipper, Johannes; Shaffer, James P; Löw, Robert; Pfau, Tilman

    2009-04-23

    Rydberg atoms have an electron in a state with a very high principal quantum number, and as a result can exhibit unusually long-range interactions. One example is the bonding of two such atoms by multipole forces to form Rydberg-Rydberg molecules with very large internuclear distances. Notably, bonding interactions can also arise from the low-energy scattering of a Rydberg electron with negative scattering length from a ground-state atom. In this case, the scattering-induced attractive interaction binds the ground-state atom to the Rydberg atom at a well-localized position within the Rydberg electron wavefunction and thereby yields giant molecules that can have internuclear separations of several thousand Bohr radii. Here we report the spectroscopic characterization of such exotic molecular states formed by rubidium Rydberg atoms that are in the spherically symmetric s state and have principal quantum numbers, n, between 34 and 40. We find that the spectra of the vibrational ground state and of the first excited state of the Rydberg molecule, the rubidium dimer Rb(5s)-Rb(ns), agree well with simple model predictions. The data allow us to extract the s-wave scattering length for scattering between the Rydberg electron and the ground-state atom, Rb(5s), in the low-energy regime (kinetic energy, <100 meV), and to determine the lifetimes and the polarizabilities of the Rydberg molecules. Given our successful characterization of s-wave bound Rydberg states, we anticipate that p-wave bound states, trimer states and bound states involving a Rydberg electron with large angular momentum-so-called trilobite molecules-will also be realized and directly probed in the near future. PMID:19396141

  8. Weyl Group Symmetric Functions Representation Theory of Lie Algebras

    E-print Network

    Ram, Arun

    of symmetric functions in the spirit of Macdonald's book [Mac] for Weyl groups other than the symmetric group of the classical symmetric function theory. See [Mac] Chapter 1 for a complete treatment. Fix a positive integer n

  9. Invertible extensions of continuous maps Real symmetric functions

    E-print Network

    Mortini, Raymond

    Invertible extensions of continuous maps Real symmetric functions Covering dimension Bass and topological stable rank Real symmetric extensions of invertible tuples of multivariable continuous functions;Invertible extensions of continuous maps Real symmetric functions Covering dimension Bass and topological

  10. WebTOP Polarization Tutorial

    NSDL National Science Digital Library

    Behringer, Ernest

    This is an interactive tutorial about Polarization based on two of the WebTOP (http://webtop.msstate.edu/) simulations, Polarization and Scattering. Covered topics include polarized and unpolarized light, waveplates, polarization by reflection and polarization by scattering.

  11. Trajectory correction propulsion for TOPS

    NASA Technical Reports Server (NTRS)

    Long, H. R.; Bjorklund, R. A.

    1972-01-01

    A blowdown-pressurized hydrazine propulsion system was selected to provide trajectory correction impulse for outer planet flyby spacecraft as the result of cost/mass/reliability tradeoff analyses. Present hydrazine component and system technology and component designs were evaluated for application to the Thermoelectric Outer Planet Spacecraft (TOPS); while general hydrazine technology was adequate, component design changes were deemed necessary for TOPS-type missions. A prototype hydrazine propulsion system was fabricated and fired nine times for a total of 1600 s to demonstrate the operation and performance of the TOPS propulsion configuration. A flight-weight trajectory correction propulsion subsystem (TCPS) was designed for the TOPS based on actual and estimated advanced components.

  12. Dark decay of Top quark

    DOE PAGESBeta

    Kong, Kyoungchui [Kansas; Lee, Hye-Sung [W&M, JLAB; Park, Myeonhun [Tokyo

    2014-04-01

    We suggest top quark decays as a venue to search for light dark force carriers. Top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 ? deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t ? b W + Z's. This is the same as the dominant top quark decay (t ? b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. We discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.

  13. Top 10 Products of 2011

    ERIC Educational Resources Information Center

    American School & University, 2011

    2011-01-01

    In 2011, American School & University (AS&U) showcased some of the hottest products in the industry. This article presents the top ten most requested products as determined by readers. The top one on the list is the Bulb crusher which can cut recycling costs by 50%, can hold 1,350 4-foot lamps in a single 55-gallon drum, can crush a 4-foot lamp in…

  14. Molecular theory for self assembling mixtures of patchy colloids and colloids with spherically symmetric attractions: The single patch case

    NASA Astrophysics Data System (ADS)

    Marshall, Bennett D.; Chapman, Walter G.

    2013-09-01

    In this work we develop a new theory to model self assembling mixtures of single patch colloids and colloids with spherically symmetric attractions. In the development of the theory we restrict the interactions such that there are short ranged attractions between patchy and spherically symmetric colloids, but patchy colloids do not attract patchy colloids and spherically symmetric colloids do not attract spherically symmetric colloids. This results in the temperature, density, and composition dependent reversible self assembly of the mixture into colloidal star molecules. This type of mixture has been recently synthesized by grafting of complimentary single stranded DNA [L. Feng, R. Dreyfus, R. Sha, N. C. Seeman, and P. M. Chaikin, Adv. Mater. 25(20), 2779-2783 (2013)], 10.1002/adma.201204864. As a quantitative test of the theory, we perform new monte carlo simulations to study the self assembly of these mixtures; theory and simulation are found to be in excellent agreement.

  15. Baryon symmetric big bang cosmology

    NASA Technical Reports Server (NTRS)

    Stecker, F. W.

    1978-01-01

    Both the quantum theory and Einsteins theory of special relativity lead to the supposition that matter and antimatter were produced in equal quantities during the big bang. It is noted that local matter/antimatter asymmetries may be reconciled with universal symmetry by assuming (1) a slight imbalance of matter over antimatter in the early universe, annihilation, and a subsequent remainder of matter; (2) localized regions of excess for one or the other type of matter as an initial condition; and (3) an extremely dense, high temperature state with zero net baryon number; i.e., matter/antimatter symmetry. Attention is given to the third assumption, which is the simplest and the most in keeping with current knowledge of the cosmos, especially as pertains the universality of 3 K background radiation. Mechanisms of galaxy formation are discussed, whereby matter and antimatter might have collided and annihilated each other, or have coexisted (and continue to coexist) at vast distances. It is pointed out that baryon symmetric big bang cosmology could probably be proved if an antinucleus could be detected in cosmic radiation.

  16. Single Top Results from CDF

    E-print Network

    Bernd Stelzer

    2007-06-02

    The CDF Collaboration has analyzed 955/pb of CDF II data to search for electroweak single top quark production at the Tevatron. We employ three different analysis techniques to search for a single top signal: multivariate likelihood functions; neural networks; the matrix element analysis technique. The sensitivities to a single top signal at the rate predicted by the Standard Model are 2.1 - 2.6 sigma. The first two analyses observe a deficit of single top-like events and set upper limits on the production cross section. The matrix element analysis observes a 2.3 sigma single top excess and measures a combined t-channel and s-channel cross section of 2.7 +1.5-1.3 pb. Using the same dataset, we have searched for non-Standard Model production of single top quarks through a heavy W' boson resonance. No evidence for a signal is observed. We exclude at the 95 % C.L. W' boson production with masses of 760 GeV/c^2 (790 GeV/c^2) in case the right handed neutrino is smaller (larger) than the mass of the W' boson.

  17. Symmetrical and unsymmetrical ?,?-nucleobase amide-conjugated systems

    PubMed Central

    Boncel, S?awomir; M?czka, Maciej; Koziol, Krzysztof K K; Motyka, Rados?aw

    2010-01-01

    Summary We present the synthesis and selected physicochemical properties of several novel symmetrical and unsymmetrical ?,?-nucleobase mono- and bis-amide conjugated systems containing aliphatic, aromatic or saccharidic linkages. The final stage of the synthesis involves condensation of a subunit bearing carboxylic group with an amine subunit. 4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMT-MM) was found to be a particularly effective condensing agent. The subunits containing carboxylic groups were obtained by acidic hydrolysis of N-1 Michael adducts of uracils or N-9 Michael adducts of 6-chloropurine with methyl acrylate. The amines used were aliphatic/aromatic diamines, adenine, 5-substituted 1-(?-aminoalkyl)uracils and 5?-amino-2?,5?-dideoxythymidine. The title compounds may find application as antiprotozoal agents. Moreover, preliminary microscopy TEM studies of supramolecular behaviour showed that target molecules with bolaamphiphilic structures were capable of forming highly ordered assemblies, mainly nanofibres. PMID:20502605

  18. Uncovering the single top: observation of electroweak top quark production

    SciTech Connect

    Benitez, Jorge Armando; /Michigan State U.

    2009-08-01

    The top quark is generally produced in quark and anti-quark pairs. However, the Standard Model also predicts the production of only one top quark which is mediated by the electroweak interaction, known as 'Single Top'. Single Top quark production is important because it provides a unique and direct way to measure the CKM matrix element V{sub tb}, and can be used to explore physics possibilities beyond the Standard Model predictions. This dissertation presents the results of the observation of Single Top using 2.3 fb{sup -1} of Data collected with the D0 detector at the Fermilab Tevatron collider. The analysis includes the Single Top muon+jets and electron+jets final states and employs Boosted Decision Tress as a method to separate the signal from the background. The resulting Single Top cross section measurement is: (1) {sigma}(p{bar p} {yields} tb + X, tqb + X) = 3.74{sub -0.74}{sup +0.95} pb, where the errors include both statistical and systematic uncertainties. The probability to measure a cross section at this value or higher in the absence of signal is p = 1.9 x 10{sup -6}. This corresponds to a standard deviation Gaussian equivalence of 4.6. When combining this result with two other analysis methods, the resulting cross section measurement is: (2) {sigma}(p{bar p} {yields} tb + X, tqb + X) = 3.94 {+-} 0.88 pb, and the corresponding measurement significance is 5.0 standard deviations.

  19. Of Molecules and Models.

    ERIC Educational Resources Information Center

    Brinner, Bonnie

    1992-01-01

    Presents an activity in which models help students visualize both the DNA process and transcription. After constructing DNA, RNA messenger, and RNA transfer molecules; students model cells, protein synthesis, codons, and RNA movement. (MDH)

  20. Symmetric Informationally Complete Measurements of Arbitrary Rank

    E-print Network

    D. M. Appleby

    2006-11-27

    There has been much interest in so-called SIC-POVMs: rank 1 symmetric informationally complete positive operator valued measures. In this paper we discuss the larger class of POVMs which are symmetric and informationally complete but not necessarily rank 1. This class of POVMs is of some independent interest. In particular it includes a POVM which is closely related to the discrete Wigner function. However, it is interesting mainly because of the light it casts on the problem of constructing rank 1 symmetric informationally complete POVMs. In this connection we derive an extremal condition alternative to the one derived by Renes et al.

  1. Gate-all-around Si-nanowire CMOS inverter logic fabricated using top-down approach

    Microsoft Academic Search

    K. D. Buddharaju; N. Singh; S. C. Rustagi; Selin H. G. Teo; L. Y. Wong; L. J. Tang; C. H. Tung; G. Q. Lo; N. Balasubramanian; D. L. Kwong

    2007-01-01

    We present, for the first time, the monolithic integration of Gate-Ail-Around (GAA) Si-nanowire FETs into CMOS logic using top-down approach. The drive currents for N-and P-MOS transistors are matched using different number of channels for each to obtain symmetric pull-up and pull-down characteristics. Sharp ON-OFF transitions with high voltage gains (up to -45) are obtained which are best reported among

  2. Averaging in spherically symmetric cosmology

    SciTech Connect

    Coley, A. A.; Pelavas, N. [Department of Mathematics and Statistics, Dalhousie University, Halifax, Nova Scotia (Canada)

    2007-02-15

    The averaging problem in cosmology is of fundamental importance. When applied to study cosmological evolution, the theory of macroscopic gravity (MG) can be regarded as a long-distance modification of general relativity. In the MG approach to the averaging problem in cosmology, the Einstein field equations on cosmological scales are modified by appropriate gravitational correlation terms. We study the averaging problem within the class of spherically symmetric cosmological models. That is, we shall take the microscopic equations and effect the averaging procedure to determine the precise form of the correlation tensor in this case. In particular, by working in volume-preserving coordinates, we calculate the form of the correlation tensor under some reasonable assumptions on the form for the inhomogeneous gravitational field and matter distribution. We find that the correlation tensor in a Friedmann-Lemaitre-Robertson-Walker (FLRW) background must be of the form of a spatial curvature. Inhomogeneities and spatial averaging, through this spatial curvature correction term, can have a very significant dynamical effect on the dynamics of the Universe and cosmological observations; in particular, we discuss whether spatial averaging might lead to a more conservative explanation of the observed acceleration of the Universe (without the introduction of exotic dark matter fields). We also find that the correlation tensor for a non-FLRW background can be interpreted as the sum of a spatial curvature and an anisotropic fluid. This may lead to interesting effects of averaging on astrophysical scales. We also discuss the results of averaging an inhomogeneous Lemaitre-Tolman-Bondi solution as well as calculations of linear perturbations (that is, the backreaction) in an FLRW background, which support the main conclusions of the analysis.

  3. A naturally light Higgs without light Top Partners

    E-print Network

    Carmona, Adrian

    2015-01-01

    We demonstrate that the inclusion of a realistic lepton sector can relax significantly the upper bound on top partner masses in minimal composite Higgs models, induced by the lightness of the Higgs boson. To that extend, we present a comprehensive survey of the impact of different realizations of the fermion sectors on the Higgs potential, with a special emphasis on the role of the leptons. The non-negligible compositeness of the $\\tau_R$ in a general class of models that address the flavor structure of the lepton sector and the smallness of the corresponding FCNCs, can have a significant effect on the potential. We find that, with the $\\tau_R$ in the symmetric representation of $SO(5)$, an increase in the maximally allowed mass of the lightest top partner of $\\gtrsim 1$ TeV is possible for minimal quark setups like the MCHM$_{5,10}$, without increasing the tuning. A light Higgs boson $m_H \\sim(100-200)$ GeV is a natural prediction of such models, which thus provide a new setup that can evade ultra-light top ...

  4. Symmetric and asymmetric hybridization in citrus spp.

    E-print Network

    Bona, Claudine M.

    2009-05-15

    it difficult to create large segregating populations for selection. Somatic hybridization by protoplast fusion circumvents sexual incompatibilities and is a powerful tool in genetic improvement. Symmetric and asymmetric hybdridization (gamma irradiation plus...

  5. PARTITION COMPLEXES, TITS BUILDINGS AND SYMMETRIC PRODUCTS

    E-print Network

    PARTITION COMPLEXES, TITS BUILDINGS AND SYMMETRIC PRODUCTS- tition complex, and identify it as the Tits building. This gives a homological relationship of equivalence relations on a finite set; a Tits building is a geometric object associated to the poset

  6. Dual PT-Symmetric Quantum Field Theories

    E-print Network

    Bender, C M; Rivers, R J

    2005-01-01

    Some quantum field theories described by non-Hermitian Hamiltonians are investigated. It is shown that for the case of a free fermion field theory with a $\\gamma_5$ mass term the Hamiltonian is $\\cal PT$-symmetric. Depending on the mass parameter this symmetry may be either broken or unbroken. When the $\\cal PT$ symmetry is unbroken, the spectrum of the quantum field theory is real. For the $\\cal PT$-symmetric version of the massive Thirring model in two-dimensional space-time, which is dual to the $\\cal PT$-symmetric scalar Sine-Gordon model, an exact construction of the $\\cal C$ operator is given. It is shown that the $\\cal PT$-symmetric massive Thirring and Sine-Gordon models are equivalent to the conventional Hermitian massive Thirring and Sine-Gordon models with appropriately shifted masses.

  7. Design, Activity, and 2.8 overset{circ}{A} Crystal Structure of a C_2 Symmetric Inhibitor Complexed to HIV1 Protease

    Microsoft Academic Search

    John Erickson; David J. Neidhart; John Vandrie; Dale J. Kempf; Xiu Chun Wang; Daniel W. Norbeck; Jacob J. Plattner; Judith W. Rittenhouse; Mary Turon; Norman Wideburg; William E. Kohlbrenner; Robert Simmer; Rosalind Helfrich; Deborah A. Paul; Mark Knigge

    1990-01-01

    A two-fold (C_2) symmetric inhibitor of the protease of human immunodeficiency virus type-1 (HIV-1) has been designed on the basis of the three-dimensional symmetry of the enzyme active site. The symmetric molecule inhibited both protease activity and acute HIV-1 infection in vitro, was at least 10,000-fold more potent against HIV-1 protease than against related enzymes, and appeared to be stable

  8. Ultrafast optical switching using photonic molecules in photonic crystal waveguides

    NASA Astrophysics Data System (ADS)

    Zhao, Yanhui; Qian, Chenjiang; Qiu, Kangsheng; Gao, Yunan; Xu, Xiulai

    2015-04-01

    We study the coupling between photonic molecules and waveguides in photonic crystal slab structures using finite-difference time-domain method and coupled mode theory. In a photonic molecule with two cavities, the coupling of cavity modes results in two super-modes with symmetric and anti-symmetric field distributions. When two super-modes are excited simultaneously, the energy of electric field oscillates between the two cavities. To excite and probe the energy oscillation, we integrate photonic molecule with two photonic crystal waveguides. In coupled structure, we find that the quality factors of two super-modes might be different because of different field distributions of super-modes. After optimizing the radii of air holes between two cavities of photonic molecule, nearly equal quality factors of two super-modes are achieved, and coupling strengths between the waveguide modes and two super-modes are almost the same. In this case, complete energy oscillations between two cavities can be obtained with a pumping source in one waveguide, which can be read out by another waveguide. Finally, we demonstrate that the designed structure can be used for ultrafast optical switching with a time scale of a few picoseconds.

  9. Ultrafast Optical Switching Using Photonic Molecules in Photonic Crystal Waveguides

    E-print Network

    Zhao, Yanhui; Qiu, Kangsheng; Gao, Yunan; Xu, Xiulai

    2015-01-01

    We study the coupling between photonic molecules and waveguides in photonic crystal slab structures using finite-difference time-domain method and coupled mode theory. In a photonic molecule with two cavities, the coupling of cavity modes results in two super-modes with symmetric and anti-symmetric field distributions. When two super-modes are excited simultaneously, the energy of electric field oscillates between the two cavities. To excite and probe the energy oscillation, we integrate photonic molecule with two photonic crystal waveguides. In coupled structure, we find that the quality factors of two super-modes might be different because of different field distributions of super-modes. After optimizing the radii of air holes between two cavities of photonic molecule, nearly equal quality factors of two super-modes are achieved, and coupling strengths between the waveguide modes and two super-modes are almost the same. In this case, complete energy oscillations between two cavities can be obtained with a p...

  10. Symmetric informationally complete measurements of arbitrary rank

    Microsoft Academic Search

    D. M. Appleby

    2007-01-01

    There has been much interest in so-called SIC-POVMs, i.e., rank 1 symmetric informationally complete positive operator valued\\u000a measures. In this paper we discuss the larger class of POVMs that are symmetric and informationally complete, but not necessarily\\u000a rank 1. This class of POVMs is of some independent interest. In particular it includes a POVM that is closely related to the

  11. Symmetric Key Structural Residues in Symmetric Proteins with Beta-Trefoil Fold

    Microsoft Academic Search

    Jianhui Feng; Mingfeng Li; Yanzhao Huang; Yi Xiao; Annalisa Pastore

    2010-01-01

    To understand how symmetric structures of many proteins are formed from asymmetric sequences, the proteins with two repeated beta-trefoil domains in Plant Cytotoxin B-chain family and all presently known beta-trefoil proteins are analyzed by structure-based multi-sequence alignments. The results show that all these proteins have similar key structural residues that are distributed symmetrically in their structures. These symmetric key structural

  12. Top for economics Rank Business School

    E-print Network

    Lin, Xiaodong

    /WHU Beisheim Tsinghua University/Insead Top for international business Rank Business School 1 2 3 4 5 6 7 8 9 10 Top for marketing Top for corporate strategy Rank Business School 1 University of PennsylvaniaTop for economics Rank Business School 1 University of Chicago: Booth Rutgers Business School

  13. Measurements of Top Properties at the Tevatron

    SciTech Connect

    Husemann, Ulrich; /Yale U.

    2007-06-01

    The large data samples of thousands of top events collected at the Tevatron experiments CDF and D{O} allow for a variety of measurements to analyze the properties of the top quark. Guided by the question ''Is the top quark observed at the Tevatron really the top quark of the standard model,'' we present Tevatron analyses studying the top production mechanism including resonant t{bar t} production, the V -A structure of the t {yields} Wb decay vertex, the charge of the top quark, and single-top production via flavor-changing neutral currents.

  14. Dark decay of Top quark

    DOE PAGESBeta

    Kong, Kyoungchui; Lee, Hye-Sung; Park, Myeonhun

    2014-04-01

    We suggest top quark decays as a venue to search for light dark force carriers. Top quark is the heaviest particle in the standard model whose decays are relatively poorly measured, allowing sufficient room for exotic decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is a recently highlighted hypothetical particle that can address some astrophysical anomalies as well as the 3.6 ? deviation in the muon g-2 measurement. We present and study a possible scenario that top quark decays as t ? b W + Z's. This is the same as the dominant topmore »quark decay (t ? b W) accompanied by one or multiple dark force carriers. The Z' can be easily boosted, and it can decay into highly collimated leptons (lepton-jet) with large branching ratio. We discuss the implications for the Large Hadron Collider experiments including the analysis based on the lepton-jets.« less

  15. Single-molecule bioelectronics.

    PubMed

    Rosenstein, Jacob K; Lemay, Serge G; Shepard, Kenneth L

    2015-07-01

    Experimental techniques that interface single biomolecules directly with microelectronic systems are increasingly being used in a wide range of powerful applications, from fundamental studies of biomolecules to ultra-sensitive assays. In this study, we review several technologies that can perform electronic measurements of single molecules in solution: ion channels, nanopore sensors, carbon nanotube field-effect transistors, electron tunneling gaps, and redox cycling. We discuss the shared features among these techniques that enable them to resolve individual molecules, and discuss their limitations. Recordings from each of these methods all rely on similar electronic instrumentation, and we discuss the relevant circuit implementations and potential for scaling these single-molecule bioelectronic interfaces to high-throughput arrayed sensing platforms. WIREs Nanomed Nanobiotechnol 2015, 7:475-493. doi: 10.1002/wnan.1323 For further resources related to this article, please visit the WIREs website. PMID:25529538

  16. Photochemistry of interstellar molecules

    NASA Technical Reports Server (NTRS)

    Stief, L. J.

    1971-01-01

    The photochemistry of two diatomic and eight polyatomic molecules is discussed quantitatively. For an interstellar molecule, the lifetime against photodecomposition depends upon the absorption cross section, the quantum yield or probability of dissociation following photon absorption, and the interstellar radiation field. The constant energy density of Habing is used for the unobserved regions of interstellar radiation field, and the field in obscuring clouds is estimated by combining the constant flux with the observed interstellar extinction curve covering the visible and ultraviolet regions. Lifetimes against photodecomposition in the unobscured regions and as a function of increasing optical thickness in obscuring clouds are calculated for the ten species. The results show that, except for CO, all the molecules have comparable lifetimes of less than one hundred years. Thus they can exist only in dense clouds and can never have been exposed to the unobscured radiation. The calculations further show that the lifetimes in clouds of moderate opacity are of the order of one million years.

  17. Positronium ions and molecules

    NASA Technical Reports Server (NTRS)

    Ho, Y. K.

    1990-01-01

    Recent theoretical studies on positronium ions and molecules are discussed. A positronium ion is a three particle system consisting of two electrons in singlet spin state, and a positron. Recent studies include calculations of its binding energy, positron annihilation rate, and investigations of its doubly excited resonant states. A positronium molecule is a four body system consisting of two positrons and two electrons in an overall singlet spin state. The recent calculations of its binding energy against the dissociation into two positronium atoms, and studies of auto-detaching states in positronium molecules are discussed. These auto-dissociating states, which are believed to be part of the Rydberg series as a result of a positron attaching to a negatively charged positronium ion, Ps-, would appear as resonances in Ps-Ps scattering.

  18. Top Quark Production at the Tevatron Collider

    SciTech Connect

    Li, Liang; /UC, Riverside

    2011-07-01

    Top quark physics has been a rich testing ground for the standard model since the top quark discovery in 1995. The large mass of top quark suggests that it could play a special role in searches for new phenomena. In this paper I provide an overview of recent top quark production cross section measurements from both CDF and D0 collaborations and also some new physics searches done in the top quark sector.

  19. Top Quark Production at the Tevatron Collider

    E-print Network

    Liang Li

    2011-07-21

    Top quark physics has been a rich testing ground for the standard model since the top quark discovery in 1995. The large mass of top quark suggests that it could play a special role in searches for new phenomena. In this paper I provide an overview of recent top quark production cross section measurements from both CDF and D0 collaborations and also some new physics searches done in the top quark sector.

  20. Top Quark Spin Correlations - Theory

    SciTech Connect

    Parke, Stephen J.; /Fermilab

    2012-02-01

    The top quark decay width (G{sub F}m{sub t}{sup 3} {approx} 1 GeV) is much larger than the QCD hadronization scale ({Lambda}{sub QCD} {approx} 0.1 GeV) and much larger than the spin decorrelation scale ({Lambda}{sub QCD}{sup 2}/m{sub t} {approx} 0.1 MeV). Therefore, spin correlations in top quark pair production are reflected in angular correlations of the decay products, see [1] and [2].

  1. Single top: prospects at LHC

    E-print Network

    Markus Cristinziani; Giovanni Petrucciani

    2008-08-05

    Single top quark processes are interesting as direct probes of the $Wtb$ vertex, and are also an important background in searches of the Higgs boson and beyond the standard model physics. Both ATLAS and CMS have performed studies with simulated data to estimate the expected uncertainty on the production cross section measurements of the three single top processes ($t$-channel, s-channel, $tW$ production) in the first years of LHC operations. Results in the different channels and for the two experiments are reported.

  2. Mighty Molecule Models

    NSDL National Science Digital Library

    Greg Rushton

    2008-01-01

    As part of the SMATHematics Project: The Wonder of Science, The Power of Mathematics--a collaborative partnership between Kennesaw State University and two local school districts, fifth graders had the opportunity to puzzle out chemical formulas of propane, methanol, and other important molecules. In addition, they explored properties that characterize certain molecules and then used their newly acquired knowledge of atoms' bonding requirements to help them build three-dimensional molecular models. The effort is succeeding--as you can see by the fifth-grade classroom experience described here.

  3. JCE Featured Molecules

    NSDL National Science Digital Library

    These interactive images are linked to molecular structures or other graphic images from articles in our print Journal. Many articles in the Journal of Chemical Education include molecular structures naturally in a two-dimensional representation. This collection of interactive Chime-based structures are chosen from some of these molecules. While many such Web-based structure collections exist, having the structures in a single location and linked to specific articles in JCE (and vice versa) will benefit both teachers and students. In addition to static images, two fully manipulable versions (Jmol, MDL Chime) of these molecules are available.

  4. Symmetrical waveform generation based on temporal pulse shaping using

    E-print Network

    Yao, Jianping

    Symmetrical waveform generation based on temporal pulse shaping using amplitude-only modulator H. Chi and J. Yao Symmetrical waveform generation based on temporal pulse shaping using only an amplitude transform of a real and symmetrical waveform is still real and symmetrical. There- fore, it is possible

  5. On the Algebraic Immunity of Symmetric Boolean Functions

    Microsoft Academic Search

    An Braeken; Bart Preneel

    2005-01-01

    In this paper, we analyse the algebraic immunity of symmetric Boolean functions. We identify a set of lowest degree annihilators for symmetric functions and propose an ecient algorithm for computing the algebraic immunity of a symmetric function. The existence of several symmetric functions with maximum algebraic immunity is proven. In this way, a new class of function which have good

  6. Investigating macromolecular complexes using top-down mass spectrometry.

    PubMed

    Boeri Erba, Elisabetta

    2014-05-01

    MS has emerged as an important tool to investigate noncovalent interactions between proteins and various ligands (e.g. other proteins, small molecules, or drugs). In particular, ESI under so-called "native conditions" (a.k.a. "native MS") has considerably expanded the scope of such investigations. For instance, ESI quadrupole time of flight (Q-TOF) instruments have been used to probe the precise stoichiometry of protein assemblies, the interactions between subunits and the position of subunits within the complex (i.e. defining core and peripheral subunits). This review highlights several illustrative native Q-TOF-based investigations and recent seminal contributions of top-down MS (i.e. Fourier transform (FT) MS) to the characterization of noncovalent complexes. Combined top-down and native MS, recently demonstrated in "high-mass modified" orbitrap mass spectrometers, and further improvements needed for the enhanced investigation of biologically significant noncovalent interactions by MS will be discussed. PMID:24723549

  7. Imaging of photoinduced tautomerism in single porphyrin molecules

    NASA Astrophysics Data System (ADS)

    Jäger, Regina; Chizhik, Anna M.; Chizhik, Alexey I.; Mack, Hans-Georg; Lyubimtsev, Alexey; Hanack, Michael; Meixner, Alfred J.

    2011-10-01

    In this work we present our new experimental and theoretical results upon investigations of the photoinduced tautomerism processes of single metal-free porphyrin-type molecules. During tautomerization a molecule changes its structure, therefore the excitation transition dipole moment (TDM) of the molecule changes its orientation. Using confocal microscopy in combination with azimuthally and radially polarized laser beams we are able to determine the orientation of the TDM as well as the orientation of a single molecule itself. In the case of tautomerism we are able to visualize this process and even the involved isomers separately. The study first focuses on two symmetrical compounds: a phthalocyanine and a porphyrin. Additionally, differences of the single molecules embedded in a polymer matrix or just spin-coated on a glass cover slide and under nitrogen flow are investigated. In the latter case we observe a higher frequency of the change of the TDM orientation. The experimental studies are supplemented by quantum chemical calculations. Variations of the molecular substituents, the environment and excitation wavelength can give new insights into the excited-state tautomerism process of a single molecule. We also introduce some suggestions for future experiments to support the understanding of the photoinduced tautomerism.

  8. Coherent anti-Stokes Raman scattering with single-molecule sensitivity using a plasmonic Fano resonance

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Zhen, Yu-Rong; Neumann, Oara; Day, Jared K.; Nordlander, Peter; Halas, Naomi J.

    2014-07-01

    Plasmonic nanostructures are of particular interest as substrates for the spectroscopic detection and identification of individual molecules. Single-molecule sensitivity Raman detection has been achieved by combining resonant molecular excitation with large electromagnetic field enhancements experienced by a molecule associated with an interparticle junction. Detection of molecules with extremely small Raman cross-sections (~10-30?cm2 sr-1), however, has remained elusive. Here we show that coherent anti-Stokes Raman spectroscopy (CARS), a nonlinear spectroscopy of great utility and potential for molecular sensing, can be used to obtain single-molecule detection sensitivity, by exploiting the unique light harvesting properties of plasmonic Fano resonances. The CARS signal is enhanced by ~11 orders of magnitude relative to spontaneous Raman scattering, enabling the detection of single molecules, which is verified using a statistically rigorous bi-analyte method. This approach combines unprecedented single-molecule spectral sensitivity with plasmonic substrates that can be fabricated using top-down lithographic strategies.

  9. Sugars as signaling molecules

    Microsoft Academic Search

    Jen Sheen; Li Zhou; Jyun-Chyun Jang

    1999-01-01

    Recent studies indicate that, in a manner similar to classical plant hormones, sugars can act as signaling molecules that control gene expression and developmental processes in plants. Crucial evidence includes uncoupling glucose signaling from its metabolism, identification of glucose sensors, and isolation and characterization of mutants and other regulatory components in plant sugar signal transduction pathways. The emerging scenario points

  10. Elements of Cryptography.Elements of Cryptography. Symmetric Encryption.Symmetric Encryption.

    E-print Network

    Fisher, Michael

    COMP 522 Elements of Cryptography.Elements of Cryptography. Symmetric Encryption.Symmetric Encryption. NSE, sections 2.1-2.2 WSPC, chapter 3 COMP 522 Cryptography · Cryptography is a collection of mathematical techniques for protecting information; · Most important technique is encryption/decryption; · We

  11. Symmetric and Anti-Symmetric Lamb Waves in a Two-Dimensional Phononic Crystal Plate

    NASA Astrophysics Data System (ADS)

    Li, Yong; Hou, Zhi-Lin; Fu, Xiu-Jun; Badreddine, M. Assouar

    2010-07-01

    It is well known that Lamb waves in a plate with a mirror plane can be separated into two uncoupled sets: symmetric and anti-symmetric modes. Based on this property, we present a revised plane wave expansion method (PWE) to calculate the band structure of a phononic crystal (PC) plate with a mirror plane. The developed PWE method can be used to calculate the band structure of symmetric and anti-symmetric modes separately, by which the depending relationship between the partial acoustic band gap (PABG), which belongs to the symmetric and anti-symmetric modes alternatively, and the position of the scatterers can be determined. As an example of its application, the band structure of the Lamb modes in a two-dimensional PC plate with two layers of void circular inclusions is investigated. The results show that the band structure for the symmetric and anti-symmetric modes can be changed by the position of the scatterers drastically, and larger PABGs will be opened when the scatterers are inserted into the area of the plate, where the elastic potential energy is concentrated.

  12. Symmetric and Hermitian In this chapter, we discuss the special classes of symmetric and Hermitian matrices.

    E-print Network

    Kilmer, Misha Elena

    that aij = ¯aji for every i, j pair. Thus, the diagonal of a Hermitian matrix must be real. Definition 5 meanings. There is such a thing as a complex-symmetric matrix (aij = aji) - a complex symmetric matrix need

  13. Time Management Top 50 Strategies

    E-print Network

    See over Time Management Top 50 Strategies Don't try to do everything on this list all at once, acceptable to you, realistic, and time-specified. 6. Ensure that goals are consistent with your values. 7 your time. 10. Use calendars ­ term, weekly & daily. 11. Carry your daily schedule with you. 12

  14. Time Management Top 50 Strategies

    E-print Network

    See over Time Management Top 50 Strategies Don't try to do everything on this list all at once, and continually improve on how you spend your time. 10. Use calendars ­ term, weekly & daily. 11. Carry your up. 15. Figure out your peak times of day for energy and do difficult tasks (e.g.: studying) during

  15. The Top 100: Associate Rankings

    ERIC Educational Resources Information Center

    Blackmon, Olivia

    2009-01-01

    This year, Diverse has added a new addition to its annual Top 100 degree producers series--recognizing, with this edition, the institutions that award the most associate degrees to students of color. More than half of minority undergraduate students start their degree quest at a community college with 55 percent of all Hispanic and Native American…

  16. Kowalevski top in quantum mechanics

    SciTech Connect

    Matsuyama, A., E-mail: spamatu@ipc.shizuoka.ac.jp

    2013-09-15

    The quantum mechanical Kowalevski top is studied by the direct diagonalization of the Hamiltonian. The spectra show different behaviors depending on the region divided by the bifurcation sets of the classical invariant tori. Some of these spectra are nearly degenerate due to the multiplicity of the invariant tori. The Kowalevski top has several symmetries and symmetry quantum numbers can be assigned to the eigenstates. We have also carried out the semiclassical quantization of the Kowalevski top by the EBK formulation. It is found that the semiclassical spectra are close to the exact values, thus the eigenstates can be also labeled by the integer quantum numbers. The symmetries of the system are shown to have close relations with the semiclassical quantum numbers and the near-degeneracy of the spectra. -- Highlights: •Quantum spectra of the Kowalevski top are calculated. •Semiclassical quantization is carried out by the EBK formulation. •Quantum states are labeled by the semiclassical integer quantum numbers. •Multiplicity of the classical torus makes the spectra nearly degenerate. •Symmetries, quantum numbers and near-degenerate spectra are closely related.

  17. Top quark mass and kinematics

    SciTech Connect

    Barberis, Emanuela; /Northeastern U.

    2006-05-01

    A summary of the results on the measurement of the Top Quark mass and the study of the kinematics of the t{bar t} system at the Tevatron collider is presented here. Results from both the CDF and D0 collaborations are reported.

  18. Top Internal Concerns for 1991.

    ERIC Educational Resources Information Center

    Meyerson, Joel W.; Johnson, Sandra L.

    1991-01-01

    The top internal issues identified by leaders in higher education management as most likely to influence colleges' financial and competitive positions in the near future include tuition policy and financing, capital renewal and replacement, research funding, planning and budgeting, and cost and productivity. (Author/MSE)

  19. TOP ALUMNI AREAS METRO AREAS

    E-print Network

    Velev, Orlin D.

    TOP ALUMNI AREAS METRO AREAS ALUMNI LOCATIONS States/NC counties STUDENT RECRUITING EVENTS 1000 The purple circles denote the metro areas with the greatest concentrations of NC State engineering alumni, large metro areas and North Carolina counties that nearly 50,000 living NC State engineering graduates

  20. OMG: Open Molecule Generator

    PubMed Central

    2012-01-01

    Computer Assisted Structure Elucidation has been used for decades to discover the chemical structure of unknown compounds. In this work we introduce the first open source structure generator, Open Molecule Generator (OMG), which for a given elemental composition produces all non-isomorphic chemical structures that match that elemental composition. Furthermore, this structure generator can accept as additional input one or multiple non-overlapping prescribed substructures to drastically reduce the number of possible chemical structures. Being open source allows for customization and future extension of its functionality. OMG relies on a modified version of the Canonical Augmentation Path, which grows intermediate chemical structures by adding bonds and checks that at each step only unique molecules are produced. In order to benchmark the tool, we generated chemical structures for the elemental formulas and substructures of different metabolites and compared the results with a commercially available structure generator. The results obtained, i.e. the number of molecules generated, were identical for elemental compositions having only C, O and H. For elemental compositions containing C, O, H, N, P and S, OMG produces all the chemically valid molecules while the other generator produces more, yet chemically impossible, molecules. The chemical completeness of the OMG results comes at the expense of being slower than the commercial generator. In addition to being open source, OMG clearly showed the added value of constraining the solution space by using multiple prescribed substructures as input. We expect this structure generator to be useful in many fields, but to be especially of great importance for metabolomics, where identifying unknown metabolites is still a major bottleneck. PMID:22985496

  1. Leptonic top-quark asymmetry predictions at LHCb

    E-print Network

    Rhorry Gauld

    2014-09-30

    The forward LHCb acceptance offers the possibility of measuring the top-quark pair asymmetry in a kinematic region that does not receive overwhelming dilution from the symmetric gluon-fusion channel. To investigate this possibility, two leptonic final states are identified, and analysis strategies are proposed for each channel with 14~TeV data. Fixed-order predictions, including $\\mathcal{O}(\\alpha_s^3)$, $\\mathcal{O}(\\alpha_s^2\\alpha_{e/w})$, and $\\mathcal{O}(\\alpha_{e/w}^2)$ contributions, are then provided for the relevant leptonic asymmetry variables in each channel. Statistically, a non-zero asymmetry is estimated to be observable beyond 5$\\sigma$ confidence level with the full LHCb 14~TeV data.

  2. Top quark studies at hadron colliders

    SciTech Connect

    Sinervo, P.K. [Toronto Univ., ON (Canada). Dept. of Physics; CDF Collaboration

    1996-08-01

    The techniques used to study top quarks at hadron colliders are presented. The analyses that discovered the top quark are described, with emphasis on the techniques used to tag {ital b} quark jets in candidate events. The most recent measurements of top quark properties by the CDF and D{null} collaborations are reviewed, including the top quark cross section, mass, branching fractions and production properties. Future top quark studies at hadron colliders are discussed, and predictions for event yields and uncertainties in the measurements of top quark properties are presented.

  3. Top-Quark Physics Results From LHC

    E-print Network

    Luca Fiorini

    2012-01-30

    The top-quark is a fundamental element of the physics program at the Large Hadron Collider (LHC). We review the current status of the top-quark measurements performed by ATLAS and CMS experiments in pp collisions at sqrt(s)=7 TeV by presenting the recent results of the top-quark production rates, top mass measurements and additional top quark properties. We will also describe the recent searches for physics beyond the Standard Model in the top-quark sector.

  4. CAST: Contraction Algorithm for Symmetric Tensors

    SciTech Connect

    Rajbhandari, Samyam; NIkam, Akshay; Lai, Pai-Wei; Stock, Kevin; Krishnamoorthy, Sriram; Sadayappan, Ponnuswamy

    2014-09-22

    Tensor contractions represent the most compute-intensive core kernels in ab initio computational quantum chemistry and nuclear physics. Symmetries in these tensor contractions makes them difficult to load balance and scale to large distributed systems. In this paper, we develop an efficient and scalable algorithm to contract symmetric tensors. We introduce a novel approach that avoids data redistribution in contracting symmetric tensors while also avoiding redundant storage and maintaining load balance. We present experimental results on two parallel supercomputers for several symmetric contractions that appear in the CCSD quantum chemistry method. We also present a novel approach to tensor redistribution that can take advantage of parallel hyperplanes when the initial distribution has replicated dimensions, and use collective broadcast when the final distribution has replicated dimensions, making the algorithm very efficient.

  5. Spherically Symmetric Thick Branes Cosmological Evolution

    E-print Network

    Bernardini, Alex E; da Rocha, Roldao

    2014-01-01

    Spherically symmetric time-dependent solutions for the 5D system of a scalar field canonically coupled to gravity are obtained and identified as an extension of recent results obtained by Ahmed, Grzadkowskia and Wudkab. The corresponding cosmology of models with regularized branes generated by such a 5D scalar field scenario is also investigated. It has been shown that the anisotropic evolution of the warp factor and consequently the Hubble like parameter are both driven by the radial coordinate on the brane, which leads to an emergent thick brane-world scenario with spherically symmetric time dependent warp factor. Meanwhile, the separability of variables depending on fifth dimension, y, which is exhibited by the equations of motion, allows one to recover the extra dimensional profiles obtained in the literature, namely the extra dimensional part of the scale (warp) factor and the scalar field dependence on y. Therefore, our results are mainly concerned with the time dependence of a spherically symmetric war...

  6. Properties of the Top Quark

    SciTech Connect

    Wicke, Daniel; /Wuppertal U., Dept. Math.

    2009-08-01

    The aim of particle physics is the understanding of elementary particles and their interactions. The current theory of elementary particle physics, the Standard Model, contains twelve different types of fermions which (neglecting gravity) interact through the gauge bosons of three forces. In addition a scalar particle, the Higgs boson, is needed for theoretical consistency. These few building blocks explain all experimental results found in the context of particle physics, so far. Nevertheless, it is believed that the Standard Model is only an approximation to a more complete theory. First of all the fourth known force, gravity, has withstood all attempts to be included until now. Furthermore, the Standard Model describes several features of the elementary particles like the existence of three families of fermions or the quantisation of charges, but does not explain these properties from underlying principles. Finally, the lightness of the Higgs boson needed to explain the symmetry breaking is difficult to maintain in the presence of expected corrections from gravity at high scales. This is the so called hierarchy problem. In addition astrophysical results indicate that the universe consists only to a very small fraction of matter described by the Standard Model. Large fractions of dark energy and dark matter are needed to describe the observations. Both do not have any correspondence in the Standard Model. Also the very small asymmetry between matter and anti-matter that results in the observed universe built of matter (and not of anti-matter) cannot be explained until now. It is thus an important task of experimental particle physics to test the predictions of the Standard Model to the best possible accuracy and to search for deviations pointing to necessary extensions or modifications of our current theoretical understanding. The top quark was predicted to exist by the Standard Model as the partner of the bottom quark. It was first observed in 1995 by the Tevatron experiments CDF and D0 and was the last of the quarks to be discovered. As the partner of the bottom quark the top quark is expected to have quantum numbers identical to that of the other known up-type quarks. Only the mass is a free parameter. We now know that it is more than 30 times heavier than the next heaviest quark, the bottom quark. Thus, within the Standard Model all production and decay properties are fully defined. Having the complete set of quarks further allows to verify constraints that the Standard Model puts on the sum of all quarks or particles. This alone is reason enough to experimentally study the top quark properties. The high value of the top quark mass and its closeness to the electroweak scale has inspired people to speculate that the top quark could have a special role in the electroweak symmetry breaking. Confirming the expected properties of the top quark experimentally establishes the top quark as we expect it to be. Any deviation from the expectations gives hints to new physics that may help to solve the outstanding questions. In this review the recent results on top quark properties obtained by the Tevatron experiments CDF and D0 are summarized. At the advent of the LHC special emphasis is given to the basic measurement methods and the dominating systematic uncertainties. After a short introduction to the Standard Model and the experimental environment in the remainder of this chapter, Chapter 2 describes the current status of top quark mass measurements. Then measurments of interaction properties are described in Chapter 3. Finally, Chapter 4 deals with analyses that consider hypothetical particles beyond the Standard Model in the observed events.

  7. Bacterial invasion reconstructed molecule by molecule

    SciTech Connect

    Werner, James H [Los Alamos National Laboratory

    2009-01-01

    We propose to visualize the initial stages of bacterial infection of a human host cell with unmatched spatial and temporal resolution. This work will develop a new capability for the laboratory (super-resolution optical imaging), will test unresolved scientific hypotheses regarding host-pathogen interaction dynamics, and leverages state of the art 3D molecular tracking instrumentation developed recently by our group. There is much to be gained by applying new single molecule tools to the important and familiar problem of pathogen entry into a host cell. For example, conventional fluorescence microscopy has identified key host receptors, such as CD44 and {alpha}5{beta}1 integrin, that aggregate near the site of Salmonella typhimurium infection of human cells. However, due to the small size of the bacteria ({approx} 2 {micro}m) and the diffraction of the emitted light, one just sees a fluorescent 'blob' of host receptors that aggregate at the site of attachment, making it difficult to determine the exact number of receptors present or whether there is any particular spatial arrangement of the receptors that facilitates bacterial adhesion/entry. Using newly developed single molecule based super-resolution imaging methods, we will visualize how host receptors are directed to the site of pathogen adhesion and whether host receptors adopt a specific spatial arrangement for successful infection. Furthermore, we will employ our 3D molecular tracking methods to follow the injection of virulence proteins, or effectors, into the host cell by the pathogen Type III secretion system (TTSS). We expect these studies to provide mechanistic insights into the early events of pathogen infection that have here-to-fore been technically beyond our reach. Our Research Goals are: Goal 1--Construct a super-resolution fluorescence microscope and use this new capability to image the spatial distribution of different host receptors (e.g. CD44, as {alpha}5{beta}1 integrin) at the point of bacterial attachment to a human cell. Goal 2--Determine if the transport method of host cell receptors to the site of Salmonella infection depends upon their initial spatial location. We hypothesize that host receptors originally near the infection site will diffuse in the host membrane till 'caught' by the bacteria, while receptors further away from the bacteria will be driven by actin to the infection site in a highly directed fashion. Goal 3--Measure the 3D path taken by a bacterial effector to find its host counterpart. We hypothesize that bacterial effectors, after passing into the host via the TTSS, fmd their host target proteins through an un-biased diffusion process (e.g. a random walk, rather than active transport). This hypothesis will be tested on the bacterial effector SopE as it searches for its host partner, Racl.

  8. The Axially Symmetric One-Monopole

    SciTech Connect

    Wong, K.-M.; Teh, Rosy [School of Physics, Universiti Sains Malaysia, 11800 USM Penang (Malaysia)

    2009-07-07

    We present new classical generalized one-monopole solution of the SU(2) Yang-Mills-Higgs theory with the Higgs field in the adjoint representation. We show that this solution with theta-winding number m = 1 and phi-winding number n = 1 is an axially symmetric generalization of the 't Hooft-Polyakov one-monopole. We construct this axially symmetric one-monopole solution by generalizing the large distance asymptotic solutions of the 't Hooft-Polyakov one-monopole to the Jacobi elliptic functions and solving the second order equations of motion numerically when the Higgs potential is vanishing. This solution is a non-BPS solution.

  9. All-optical symmetric ternary logic gate

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Tanay

    2010-09-01

    Symmetric ternary number (radix=3) has three logical states (1¯, 0, 1). It is very much useful in carry free arithmetical operation. Beside this, the logical operation using this type of number system is also effective in high speed computation and communication in multi-valued logic. In this literature all-optical circuits for three basic symmetrical ternary logical operations (inversion, MIN and MAX) are proposed and described. Numerical simulation verifies the theoretical model. In this present scheme the different ternary logical states are represented by different polarized state of light. Terahertz optical asymmetric demultiplexer (TOAD) based interferometric switch has been used categorically in this manuscript.

  10. Self-assembly of ?-6T Molecule on Ag(100) and Related STM Induced Luminescence

    NASA Astrophysics Data System (ADS)

    Chen, Liu-guo; Zhang, Chao; Zhang, Rui; Dong, Zhen-chao

    2011-12-01

    We have investigated the self-assembly and light emission properties of organic ?-sexithiophene (?-6T) molecules on Ag(100) under different coverage by scanning tunneling microscopy (STM). At very low coverage, the ?-6T molecules form a unique enantiomer by grouping four molecules into a windmill supermolecular structure. As the coverage is increased, ?-6T molecules tend to pack side by side into a denser stripe structure. Further increase of the coverage will lead to the layer-by-layer growth of molecules on Ag(100) with the lower-layer stripe pattern serving as a template. Molecular fluorescence for ?-6T molecules on Ag(100) at a coverage of five monolayers has been detected by light excitations, which indicates a well decoupled electronic states for the top-layer ?-6T molecules. However, the STM induced luminescent spectra for the same sample reveal only plasmonic-like emission. The absence of intramolecular fluorescence in this case suggests that the electronic decoupling is not a sufficient condition for generating photon emission from molecules. For intramolecular fluorescence to occur, the orientation of the dynamic dipole moment of molecules and the energy-level alignment at the molecule-metal interface are also important so that molecules can be effectively excited through efficient dipolar coupling with local plasmons and by injecting holes into the molecules.

  11. Let's Make Molecules

    NSDL National Science Digital Library

    Sciencenter

    2010-01-01

    In this activity, learners use gumdrops and toothpicks to model the composition and molecular structure of three greenhouse gases: carbon dioxide (CO2), water vapor (H2O) and methane (CH4). Learners explore how greenhouse gases are released into the atmosphere as well as how these gases contribute to global climate change. This activity guide includes an extension activity in which learners move their bodies to model the arrangement of atoms in a methane molecule.

  12. Strange skyrmion molecules

    NASA Astrophysics Data System (ADS)

    Kopeliovich, Vladimir B.; Stern, Boris E.

    1997-05-01

    Composed skyrmions with B=2, strangeness content close to 0.5 and the binding energy of several tens of Mev are described. These skyrmions are obtained starting from the system of two B=1 hedgehogs located in different SU(2) subgroups of SU(3) and have the mass and baryon number distribution of molecular (dipole) type. The quantization of zero modes of skyrmion molecules and physics consequences of their existence are discussed.

  13. Heterocyclic small molecule peptidomimetics 

    E-print Network

    Liu, Jing

    2009-05-15

    of DOCTOR OF PHILOSOPHY Approved by: Chair of Commite, Kevin Burges Commite Members, Brian T. Connel Rajesh Miranda Eric E. Simanek Head of Department, David Russel December 2008 Major Subject: Chemistry ii ABSTRACT... Heterocyclic Smal Molecule Peptidomimetics. (December 2008) Jing Liu, B.S., Nankai University Chair of Advisory Commite: Dr. Kevin Burges Polymer-supported synthesis of a close analog (i.e. A) of an early lead, a 14- membered ring peptidomimetic D3...

  14. Probing the site-dependent Kondo response of nanostructured graphene with organic molecules.

    PubMed

    Garnica, Manuela; Stradi, Daniele; Calleja, Fabián; Barja, Sara; Díaz, Cristina; Alcamí, Manuel; Arnau, Andrés; Vázquez de Parga, Amadeo L; Martín, Fernando; Miranda, Rodolfo

    2014-08-13

    TCNQ molecules are used as a sensitive probe for the Kondo response of the electron gas of a nanostructured graphene grown on Ru(0001) presenting a moiré pattern. All adsorbed molecules acquired an extra electron by charge transfer from the substrate, but only those adsorbed in the FCC-Top areas of the moiré show magnetic moment and Kondo resonance in the STS spectra. DFT calculations trace back this behavior to the existence of a surface resonance in the low areas of the graphene moiré, whose density distribution strongly depends on the stacking sequence of the moiré area and effectively quenches the magnetic moment for HCP-Top sites. PMID:25054236

  15. Thermoelectric Outer Planets Spacecraft (TOPS)

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The research and advanced development work is reported on a ballistic-mode, outer planet spacecraft using radioisotope thermoelectric generator (RTG) power. The Thermoelectric Outer Planet Spacecraft (TOPS) project was established to provide the advanced systems technology that would allow the realistic estimates of performance, cost, reliability, and scheduling that are required for an actual flight mission. A system design of the complete RTG-powered outer planet spacecraft was made; major technical innovations of certain hardware elements were designed, developed, and tested; and reliability and quality assurance concepts were developed for long-life requirements. At the conclusion of its active phase, the TOPS Project reached its principal objectives: a development and experience base was established for project definition, and for estimating cost, performance, and reliability; an understanding of system and subsystem capabilities for successful outer planets missions was achieved. The system design answered long-life requirements with massive redundancy, controlled by on-board analysis of spacecraft performance data.

  16. Top Quark Production at the LHC

    E-print Network

    Francesco Spanò; for the ATLAS; CMS collaborations

    2011-12-16

    Top quark production in proton proton collisions at the Large Hadron Collider (LHC) is reviewed using data collected by the ATLAS and CMS detectors. Most recent results on searches for new physics related to top quark production mechanism are included.

  17. Top partner probes of extended Higgs sectors

    E-print Network

    Kearney, John

    Natural theories of the weak scale often include fermionic partners of the top quark. If the electroweak symmetry breaking sector contains scalars beyond a single Higgs doublet, then top partners can have sizable branching ...

  18. Fruit Salad with Light Whipped Topping Ingredients

    E-print Network

    Liskiewicz, Maciej

    pineapple chunks in juice 8 ounces fat-free yogurt, plain 8 ounces lite whipped topping Directions 1. Drain fruit cocktail and pineapple chunks. 2. Place fruit in bowl. 3. Stir in yogurt and whipped topping. 4

  19. Observation of the Top Quark

    Microsoft Academic Search

    S. Abachi

    1995-01-01

    he D0 Collaboration reports on a search for the standard model top quark in pp? collisions at ?s = 1.8 TeV at the Fermilab Tevatron with an integrated luminosity of approximately 50 pb^{-1}. We have searched for tt? production in the dilepton and single-lepton decay channels with and without tagging of b-quark jets. We observed 17 events with an expected

  20. Planck scale from top condensation

    SciTech Connect

    Bai Yang [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois 60510 (United States); Carena, Marcela [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois 60510 (United States); Enrico Fermi Institute, University of Chicago, 5640 Ellis Avenue, Chicago, Illinois 60637 (United States); Ponton, Eduardo [Department of Physics, Columbia University, 538 W. 120th St, New York, New York 10027 (United States)

    2010-03-15

    We propose a scenario in which the Planck scale is dynamically linked to the electroweak scale induced by top condensation. The standard model field content, without the Higgs, is promoted to a 5D warped background. There is also an additional 5D fermion with the quantum numbers of the right-handed top. Localization of the zero-modes leads, at low-energies, to a Nambu-Jona-Lasinio model that also stabilizes the radion field dynamically thus explaining the hierarchy between the Planck scale and v{sub EW}=174 GeV. The top mass arises dynamically from the electroweak breaking condensate. The other standard model fermion masses arise naturally from higher-dimension operators, and the fermion mass hierarchies and flavor structure can be explained from the localization of the zero-modes in the extra dimension. If other contributions to the radion potential except those directly related to electroweak symmetry breaking are engineered to be suppressed, the KK scale is predicted to be about 2 orders of magnitude above the electroweak scale, rendering the model easily consistent with electroweak precision data. The model predicts a heavy (composite) Higgs with a mass of about 500 GeV and standard-model-like properties, and a vectorlike quark with non-negligible mixing with the top quark and mass in the 1.6-2.9 TeV range. Both can be within the reach of the LHC. It also predicts a radion with a mass of a few GeV that is very weakly coupled to standard model matter.

  1. Measurements of Top Quark Properties

    SciTech Connect

    Cerrito, Lucio

    2009-05-01

    Preliminary results on the measurement of four selected properties of the top quark are presented. The relative fraction of t{bar t} production through gluon fusion has been measured in the t{bar t} dilepton decay channel by the CDF Collaboration as F{sub gg} = 0.53{sub -0.38}{sup +0.36}. Using an integrated luminosity of 2.7 fb{sup -1} collected with the CDF II detector, we also determine the t{bar t} differential cross section with respect to values up to {approx}1 TeV of the t{bar t} invariant mass. We present a model-independent measurement of the helicity of W bosons produced in top quark decays, using an integrated luminosity of up to 2.7 fb{sup -1} collected by the D0 detector, and find the fraction of longitudinal W bosons f{sub 0} = 0.49 {+-} 0.14, and the fraction of right-handed W bosons f{sub +} = 0.11 {+-} 0.08. Finally, we measure the parton level forward-backward asymmetry of pair produced top quarks using an integrated luminosity of 3.2 fb{sup -1} collected with the CDF II detector, and find A{sub FB} = 0.19 {+-} 0.07. All results are consistent with the predictions of the standard model.

  2. Top quark Physics at the Tevatron

    E-print Network

    Yvonne Peters; for the CDF; D0 Collaborations

    2012-01-06

    When the heaviest elementary particle known today, the top quark, was discovered in 1995 by the CDF and D0 collaborations at the Fermilab Tevatron collider, a large program to study this particle in details has started. In this article, an overview of the status of top quark physics at the Tevatron is presented. In particular, recent results on top quark production, properties and searches using top quarks are discussed.

  3. Evidence for production of single top quarks

    Microsoft Academic Search

    V. M. Abazov; B. Abbott; M. Abolins; B. S. Acharya; M. Adams; T. Adams; E. Aguilo; S. H. Ahn; M. Ahsan; G. D. Alexeev; G. Alkhazov; A. Alton; G. Alverson; G. A. Alves; M. Anastasoaie; L. S. Ancu; T. Andeen; S. Anderson; M. S. Anzelc; M. Aoki; Y. Arnoud; M. Arov; M. Arthaud; A. Askew; B. Åsman; A. C. S. Assis Jesus; O. Atramentov; C. Avila; C. Ay; F. Badaud; A. Baden; L. Bagby; B. Baldin; D. V. Bandurin; P. Banerjee; S. Banerjee; E. Barberis; A.-F. Barfuss; P. Bargassa; P. Baringer; J. F. Bartlett; U. Bassler; D. Bauer; S. Beale; A. Bean; M. Begalli; M. Begel; C. Belanger-Champagne; L. Bellantoni; A. Bellavance; J. A. Benitez; S. B. Beri; G. Bernardi; R. Bernhard; I. Bertram; M. Besançon; R. Beuselinck; V. A. Bezzubov; P. C. Bhat; V. Bhatnagar; C. Biscarat; G. Blazey; F. Blekman; S. Blessing; D. Bloch; K. Bloom; A. Boehnlein; D. Boline; T. A. Bolton; E. E. Boos; G. Borissov; T. Bose; A. Brandt; R. Brock; G. Brooijmans; A. Bross; D. Brown; N. J. Buchanan; D. Buchholz; M. Buehler; V. Buescher; V. Bunichev; S. Burdin; S. Burke; T. H. Burnett; C. P. Buszello; J. M. Butler; P. Calfayan; S. Calvet; J. Cammin; W. Carvalho; B. C. K. Casey; H. Castilla-Valdez; S. Chakrabarti; D. Chakraborty; K. M. Chan; A. Chandra; F. Chevallier; E. Cheu; D. K. Cho; S. Choi; B. Choudhary; L. Christofek; T. Christoudias; S. Cihangir; D. Claes; Y. Coadou; M. Corcoran; W. E. Cooper; M.-C. Cousinou; F. Couderc; S. Crépé-Renaudin; D. Cutts; M. Cwiok; H. da Motta; A. Das; G. Davies; K. de; S. J. de Jong; E. de La Cruz-Burelo; C. de Oliveira Martins; J. D. Degenhardt; F. Déliot; M. Demarteau; R. Demina; D. Denisov; S. P. Denisov; S. Desai; H. T. Diehl; M. Diesburg; A. Dominguez; H. Dong; L. V. Dudko; L. Duflot; S. R. Dugad; D. Duggan; A. Duperrin; J. Dyer; A. Dyshkant; M. Eads; D. Edmunds; J. Ellison; V. D. Elvira; Y. Enari; S. Eno; P. Ermolov; H. Evans; A. Evdokimov; V. N. Evdokimov; A. V. Ferapontov; T. Ferbel; F. Fiedler; F. Filthaut; W. Fisher; H. E. Fisk; M. Fortner; H. Fox; S. Fu; S. Fuess; T. Gadfort; C. F. Galea; E. Gallas; C. Garcia; A. Garcia-Bellido; V. Gavrilov; P. D. Grannis; W. Geist; D. Gelé; C. E. Gerber; Y. Gershtein; D. Gillberg; G. Ginther; N. Gollub; B. Gómez; A. Goussiou; H. Greenlee; Z. D. Greenwood; E. M. Gregores; G. Grenier; Ph. Gris; J.-F. Grivaz; A. Grohsjean; S. Grünendahl; M. W. Grünewald; F. Guo; J. Guo; G. Gutierrez; P. Gutierrez; A. Haas; N. J. Hadley; P. Haefner; S. Hagopian; J. Haley; I. Hall; R. E. Hall; L. Han; K. Harder; A. Harel; R. Harrington; J. M. Hauptman; R. Hauser; J. Hays; T. Hebbeker; D. Hedin; J. G. Hegeman; J. M. Heinmiller; A. P. Heinson; U. Heintz; C. Hensel; K. Herner; G. Hesketh; M. D. Hildreth; R. Hirosky; J. D. Hobbs; B. Hoeneisen; H. Hoeth; M. Hohlfeld; S. J. Hong; S. Hossain; P. Houben; Y. Hu; Z. Hubacek; V. Hynek; I. Iashvili; R. Illingworth; A. S. Ito; S. Jabeen; M. Jaffré; S. Jain; K. Jakobs; C. Jarvis; R. Jesik; K. Johns; C. Johnson; M. Johnson; A. Jonckheere; P. Jonsson; A. Juste; E. Kajfasz; A. M. Kalinin; J. M. Kalk; S. Kappler; D. Karmanov; P. A. Kasper; I. Katsanos; D. Kau; V. Kaushik; R. Kehoe; S. Kermiche; N. Khalatyan; A. Khanov; A. Kharchilava; Y. M. Kharzheev; D. Khatidze; T. J. Kim; M. H. Kirby; M. Kirsch; B. Klima; J. M. Kohli; J.-P. Konrath; V. M. Korablev; A. V. Kozelov; J. Kraus; D. Krop; T. Kuhl; A. Kumar; A. Kupco; T. Kurca; J. Kvita; F. Lacroix; D. Lam; S. Lammers; G. Landsberg; P. Lebrun; W. M. Lee; A. Leflat; J. Lellouch; J. Leveque; J. Li; L. Li; Q. Z. Li; S. M. Lietti; J. G. R. Lima; D. Lincoln; J. Linnemann; V. V. Lipaev; R. Lipton; Y. Liu; Z. Liu; A. Lobodenko; M. Lokajicek; P. Love; H. J. Lubatti; R. Luna; A. L. Lyon; A. K. A. Maciel; D. Mackin; R. J. Madaras; P. Mättig; C. Magass; A. Magerkurth; P. K. Mal; H. B. Malbouisson; S. Malik; V. L. Malyshev; H. S. Mao; Y. Maravin; B. Martin; R. McCarthy; A. Melnitchouk; L. Mendoza; P. G. Mercadante; M. Merkin; K. W. Merritt; A. Meyer; J. Meyer; T. Millet; J. Mitrevski; J. Molina; R. K. Mommsen; N. K. Mondal; R. W. Moore; T. Moulik; G. S. Muanza; M. Mulders; M. Mulhearn; O. Mundal; L. Mundim; E. Nagy; M. Naimuddin; M. Narain; N. A. Naumann; H. A. Neal; J. P. Negret; P. Neustroev; H. Nilsen; H. Nogima; S. F. Novaes; T. Nunnemann; V. O'Dell; D. C. O'Neil; G. Obrant; C. Ochando; D. Onoprienko; N. Oshima; N. Osman; J. Osta; R. Otec; G. J. Otero Y Garzón; M. Owen; P. Padley; M. Pangilinan; N. Parashar; S.-J. Park; S. K. Park; J. Parsons; R. Partridge; N. Parua; A. Patwa; G. Pawloski; B. Penning; M. Perfilov; K. Peters; Y. Peters; P. Pétroff; M. Petteni; R. Piegaia; J. Piper; M.-A. Pleier; P. L. M. Podesta-Lerma; V. M. Podstavkov; Y. Pogorelov; M.-E. Pol; P. Polozov; B. G. Pope; A. V. Popov; C. Potter; W. L. Prado da Silva; H. B. Prosper; S. Protopopescu; J. Qian; A. Quadt; B. Quinn; A. Rakitine; M. S. Rangel; K. Ranjan; P. N. Ratoff; P. Renkel; S. Reucroft; P. Rich; J. Rieger

    2008-01-01

    We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron p pmacr collider. The standard model predicts that the electroweak interaction can produce a top quark together with an antibottom quark or light quark, without the antiparticle top-quark partner that is always produced from strong-coupling processes. Top quarks were first observed

  4. Heavy flavour physics from top to bottom

    SciTech Connect

    Paulini, M. [Lawrence Berkeley National Lab., CA (United States); CDF and D0 Collaborations

    1997-01-01

    We review the status of heavy flavour physics at the Fermilab Tevatron collider by summarizing recent top quark and B physics results from CDF and D0. In particular we discuss the measurement of the top quark mass and top production cross section as well as B meson lifetimes and time dependent B{bar B} mixing results. An outlook of perspectives for top and B physics in Run II starting in 1999 is also given. 38 refs., 23 figs., 8 tabs.

  5. Higher Dimensional Spherically Symmetric Gravitational Collapse

    NASA Astrophysics Data System (ADS)

    Ahmad, Zahid; Haseeb, Abdul

    2014-04-01

    In this paper, the gravitational collapse of type I matter has been investigated in the context of higher dimensional spherically symmetric spacetime. The equation of state with b>0 is assumed. The effects of more than four dimensions on the nature of the singularity are being discussed.

  6. ccsd00002799, KILLING FORMS ON SYMMETRIC SPACES

    E-print Network

    ccsd­00002799, version 1 ­ 7 Sep 2004 KILLING FORMS ON SYMMETRIC SPACES FLORIN BELGUN, ANDREI MOROIANU AND UWE SEMMELMANN Abstract. Killing forms on Riemannian manifolds are di#11;erential forms whose space carries a non{parallel Killing p{form (p #21; 2) if and only if it isometric to a Riemannian

  7. Symmetrical parametrizations of the lepton mixing matrix

    SciTech Connect

    Rodejohann, W. [Max-Planck-Institut fuer Kernphysik, Postfach 103980, 69029 Heidelberg (Germany); Valle, J. W. F. [AHEP Group, Institut de Fisica Corpuscular--C.S.I.C./Universitat de Valencia, Edificio Institutos de Paterna, Apt 22085, E-46071 Valencia (Spain)

    2011-10-01

    Advantages of the original symmetrical form of the parametrization of the lepton mixing matrix are discussed. It provides a conceptually more transparent description of neutrino oscillations and lepton number violating processes like neutrinoless double beta decay, clarifying the significance of Dirac and Majorana phases. It is also ideal for parametrizing scenarios with light sterile neutrinos.

  8. Symmetric Projections of the Entropy Region

    E-print Network

    Cai, Xinyi

    2014-11-19

    OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii 1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Thesis... Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. ON THE AVERAGE ENTROPY REGIONS . . . . . . . . . . . . . . . . . 6 2.1 Group-Induced Symmetric Projections . . . . . . . . . . . . . . . . . 7 2.2 The Total-Average Projection...

  9. HOMOGENEOUS EINSTEINWEYL STRUCTURES ON SYMMETRIC SPACES

    E-print Network

    Kerr, Megan M.

    is Date: August 18, 1997. 1 #12;2 MEGAN M. KERR the Gauduchon metric. Hence we will assume from nowHOMOGENEOUS EINSTEIN­WEYL STRUCTURES ON SYMMETRIC SPACES MEGAN M. KERR Abstract. In this paper we of the metric ( is a function on M). Three-dimensional compact Einstein­Weyl spaces have been completely

  10. Vacuum calculations in azimuthally symmetric geometry

    Microsoft Academic Search

    M. S. Chance

    1997-01-01

    A robustly accurate and effective method is presented to solve Laplace{close_quote}s equation in general azimuthally symmetric geometry for the magnetic scalar potential in the region surrounding a plasma discharge which may or may not contain external conductors. These conductors can be topologically toroidal or spherical, and may have toroidal gaps in them. The solution is incorporated into the various magnetohydrodynamic

  11. Vacuum calculations in azimuthally symmetric geometry

    Microsoft Academic Search

    M. S. Chance

    1997-01-01

    A robustly accurate and effective method is presented to solve Laplace’s equation in general azimuthally symmetric geometry for the magnetic scalar potential in the region surrounding a plasma discharge which may or may not contain external conductors. These conductors can be topologically toroidal or spherical, and may have toroidal gaps in them. The solution is incorporated into the various magnetohydrodynamic

  12. VACUUM calculation in azimuthally symmetric geometry

    Microsoft Academic Search

    1996-01-01

    A robustly accurate and effective method is presented to solve Laplace`s equation in general azimuthally symmetric geometry for the magnetic scalar potential in the region surrounding a plasma discharge which may or may not contain external conducting shells. These shells can be topologically toroidal or spherical, and may have toroidal gaps in them. The solution is incorporated into the various

  13. Ch.19 Symmetric Encryption and Message Confidentiality

    E-print Network

    Dong, Yingfei

    1 1 Ch.19 Symmetric Encryption and Message Confidentiality · HW 9 and 10: upto this Wen · Next week: Ch.20 Public key Crypto · Conventional Encryption Principles · Conventional Encryption Algorithms: DES, AES · Cipher Block Modes of Operation: Block vs. stream · Location of Encryption Devices · Key

  14. NonceBased Symmetric Encryption Phillip Rogaway

    E-print Network

    Rogaway, Phillip

    Nonce­Based Symmetric Encryption Phillip Rogaway Dept. of Computer Science, University encryption schemes are usually formalized so as to make the encryption operation a probabilistic or state­dependent func­ tion E of the message M and the key K: the user supplies M and K and the encryption process does

  15. Symmetric Stereo Matching for Occlusion Handling

    Microsoft Academic Search

    Jian Sun; Yin Li; Sing Bing Kang; Heung-Yeung Shum

    2005-01-01

    In this paper, we propose a symmetric stereo model to han- dle occlusion in dense two-frame stereo. Our occlusion reasoning is directly based on the visibility constraint that is more general than both ordering and uniqueness con- straints used in previous work. The visibility constraint requires occlusion in one image and disparity in the other to be consistent. We embed

  16. Unidirectional nonlinear PT-symmetric optical structures

    SciTech Connect

    Ramezani, Hamidreza [Department of Physics, Wesleyan University, Middletown, Connecticut 06459 (United States); Kottos, Tsampikos [Department of Physics, Wesleyan University, Middletown, Connecticut 06459 (United States); Max-Planck-Institute for Dynamics and Self-Organization, D-37073 Goettingen (Germany); El-Ganainy, Ramy; Christodoulides, Demetrios N. [College of Optics and Photonics-CREOL, University of Central Florida, Orlando, Florida 32816 (United States)

    2010-10-15

    We show that nonlinear optical structures involving a balanced gain-loss profile can act as unidirectional optical valves. This is made possible by exploiting the interplay between the fundamental symmetries of parity (P) and time (T), with optical nonlinear effects. This unidirectional dynamics is specifically demonstrated for the case of an integrable PT-symmetric nonlinear system.

  17. Reciprocal Symmetric and Origin of Quantum Statistics

    E-print Network

    Mushfiq Ahmad

    2007-03-21

    Boltzmann's differential equation is replaced by the corresponding reciprocal symmetric finite difference equation. Finite difference translates discreteness of energy. Boltzmann's function, then, splits into two reciprocally related functions. One of them gives Planck's radiation relation and the other one gives the corresponding Fermi-Dirac relation.

  18. Symmetrization of cyclic sigma-telluranes

    SciTech Connect

    Sadekov, I.D.; Rivkin, B.B.; Maslakov, A.G.; Minkin, V.I.

    1987-09-01

    The authors examine reactions involving cyclic sigma-telluranes. Refluxing 5,5-dichlorodibenzotellurophene with tellurium tetrachloride in o-dichlorobenzene results in symmetrization and the formation of 2,2'-bis(trichlorotelluro)diphenyl in high yield. The other compounds formed and described are polymeric ditelluride, dibenzotellurophene, and dimethyltellurium dibromide.

  19. Resonances for Symmetric Two-Barrier Potentials

    ERIC Educational Resources Information Center

    Fernandez, Francisco M.

    2011-01-01

    We describe a method for the accurate calculation of bound-state and resonance energies for one-dimensional potentials. We calculate the shape resonances for symmetric two-barrier potentials and compare them with those coming from the Siegert approximation, the complex scaling method and the box-stabilization method. A comparison of the…

  20. PARTITION COMPLEXES, TITS BUILDINGS AND SYMMETRIC PRODUCTS

    E-print Network

    PARTITION COMPLEXES, TITS BUILDINGS AND SYMMETRIC PRODUCTS G. Z. ARONE AND W. G. DWYER Abstract. We construct a homological approximation to the par- tition complex, and identify it as the Tits building on a finite set; a Tits building is a geometric object associated to the poset of subspaces of a vector space

  1. MINIMUM POWER SYMMETRIC CONNECTIVITY PROBLEM IN

    E-print Network

    Gambardella, Luca Maria

    the probability of detection by enemy radar. In this paper, we focus on the minimum power topology problemMINIMUM POWER SYMMETRIC CONNECTIVITY PROBLEM IN WIRELESS NETWORKS: A NEW APPROACH Roberto preprocessing technique. Keywords: Wireless networks, minimum power topology, exact algorithms. 1. Introduction

  2. Stability Analysis of a Symmetrical Induction Machine

    Microsoft Academic Search

    ROBERT H. NELSON; THOMAS A. LIPO; PAUL C. KRAUSE

    1969-01-01

    A stability study of an induction machine is performed by applying the root-locus criterion to the equations which describe the behavior of the machine during small displacements about a steady-state operating point. This investigation reveals that a symmetrical induction machine may become unstable at low speeds (low frequencies) even though balanced, constant amplitude, sinusoidal voltages are applied to the stator

  3. Symmetric Projections of the Entropy Region 

    E-print Network

    Cai, Xinyi

    2014-11-19

    OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii 1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Thesis... Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. ON THE AVERAGE ENTROPY REGIONS . . . . . . . . . . . . . . . . . 6 2.1 Group-Induced Symmetric Projections . . . . . . . . . . . . . . . . . 7 2.2 The Total-Average Projection...

  4. Realizability of stationary spherically symmetric transonic accretion

    E-print Network

    Arnab K. Ray; J. K. Bhattacharjee

    2004-09-20

    The spherically symmetric stationary transonic (Bondi) flow is considered a classic example of an accretion flow. This flow, however, is along a separatrix, which is usually not physically realizable. We demonstrate, using a pedagogical example, that it is the dynamics which selects the transonic flow.

  5. Vector fields on $?$-symmetric flag supermanifolds

    E-print Network

    E. G. Vishnyakova

    2015-06-07

    The main result of this paper is the computation of the Lie superalgebras of holomorphic vector fields on the complex $\\Pi$-symmetric flag supermanifolds, introduced by Yu.I.~Manin. We prove that with one exception any vector field is fundamental with respect to the natural action of the Lie superalgebra $\\mathfrak q_n(\\mathbb C)$.

  6. Irreducible complexity of iterated symmetric bimodal maps

    Microsoft Academic Search

    J. P. Lampreia; R. Severino; J. Sousa Ramos

    2004-01-01

    We introduce a tree structure for the iterates of symmetric bimodal maps and identify a subset which we prove to be isomorphic to the family of unimodal maps. This subset is used as a second factor for a $\\\\ast $-product that we define in the space of bimodal kneading sequences. Finally, we give some properties for this product and study

  7. Symmetric Publish/Subscribe via Constraint Publication

    E-print Network

    Symmetric Publish/Subscribe via Constraint Publication Anthony Tomasic, Charles Garrod, and Kris 15213 Abstract Current publish / subscribe systems o#er a range of expressive subscription languages for con­ straints. However, classical systems restrict the publish operation to be a single published

  8. Symmetric Publish/Subscribe via Constraint Publication

    E-print Network

    Symmetric Publish/Subscribe via Constraint Publication Anthony Tomasic, Charles Garrod, and Kris 15213 Abstract Current publish / subscribe systems offer a range of expressive subscription languages for con- straints. However, classical systems restrict the publish operation to be a single published

  9. Induction of apoptosis in colon cancer cells by a novel topoisomerase I inhibitor TopIn

    SciTech Connect

    Bae, Soo Kyung [College of Pharmacy, The Catholic University of Korea, Bucheon 420-743 (Korea, Republic of)] [College of Pharmacy, The Catholic University of Korea, Bucheon 420-743 (Korea, Republic of); Gwak, Jungsug [Department of Advanced Fermentation Fusion Science and Technology, Kookmin University, Seoul 136-702 (Korea, Republic of)] [Department of Advanced Fermentation Fusion Science and Technology, Kookmin University, Seoul 136-702 (Korea, Republic of); Song, Im-Sook [PharmcoGenomics Research Center, Inje University College of Medicine, Busan 614-735 (Korea, Republic of)] [PharmcoGenomics Research Center, Inje University College of Medicine, Busan 614-735 (Korea, Republic of); Park, Hyung-Soon [Probiond Co., Ltd., Seoul 143-834 (Korea, Republic of)] [Probiond Co., Ltd., Seoul 143-834 (Korea, Republic of); Oh, Sangtaek, E-mail: ohsa@kookmin.ac.kr [Department of Advanced Fermentation Fusion Science and Technology, Kookmin University, Seoul 136-702 (Korea, Republic of)] [Department of Advanced Fermentation Fusion Science and Technology, Kookmin University, Seoul 136-702 (Korea, Republic of)

    2011-05-27

    Highlights: {yields} TopIn activates p53-dependent transcription in colon cancer cells. {yields} TopIn induces apoptosis in colon cancer cells. {yields} TopIn selectively inhibits topoisomerase I activity. {yields} TopIn does not affect the activity of BCRP and MDR-1. -- Abstract: The tumor suppressor p53 plays an important role in cellular emergency mechanisms through regulating the genes involved in cell cycle arrest and apoptosis. To identify small molecules that can activate p53-responsive transcription, we performed chemical screening using genetically engineered HCT116 reporter cells. We found that TopIn (7-phenyl-6H-[1,2,5]oxadiazolo[3,4-e]indole 3-oxide) efficiently activated p53-mediated transcriptional activity and induced phosphorylation of p53 at Ser15, thereby stabilizing the p53 protein. Furthermore, TopIn upregulated the expression of p21{sup WAF1/CIP1}, a downstream target of p53, and suppressed cellular proliferation in various colon cancer cells. Additionally, TopIn induced DNA fragmentation, caspase-3/7 activation and poly ADP ribose polymerase cleavage, typical biochemical markers of apoptosis, in p53 wild-type and mutated colon cancer cells. Finally, we found that TopIn inhibited topoisomerase I activity, but not topoisomerase II, in vitro and induced the formation of the topoisomerase I-DNA complex in HCT116 colon cancer cells. Unlike camptothecin (CPT) and its derivative SN38, TopIn did not affect the activity of the ATP-binding cassette transporter breast cancer resistance protein (BCRP) or multidrug-resistant protein-1 (MDR-1). These results suggest that TopIn may present a promising new topoisomerase I-targeting anti-tumor therapeutics.

  10. Top quark physics expectations at the LHC

    E-print Network

    Andrei Gaponenko; for the ATLAS Collaboration; for the CMS Collaboration

    2008-10-22

    The top quark will be produced copiously at the LHC. This will make both detailed physics studies and the use of top quark decays for detector calibration possible. This talk reviews plans and prospects for top physics activities in the ATLAS and CMS experiments.

  11. Top quark mass measurements at CDF

    Microsoft Academic Search

    T. Maki

    2008-01-01

    The top quark mass is interesting both as a fundamental parameter of the standard model as well as an important input to precision electroweak tests. The CDF Collaboration has measured the top quark mass with high precision in all decay channels with complementary methods. A combination of the results from CDF gives a top quark mass of 170.5 ± 13(stat)

  12. Top Mass Measurements at the Tevatron

    E-print Network

    M. H. L. S. Wang

    2009-04-02

    We present the latest measurements of the top quark mass from the Tevatron. The different top decay channels and measurement techniques used for these results are also described. The world average of the top quark mass based on some of these new results combined with previous results is mtop=172.6+-1.4 GeV.

  13. In Praise of Top-Down Leadership

    ERIC Educational Resources Information Center

    Dufour, Richard

    2007-01-01

    In the ongoing debate of the efficacy of top-down versus bottom-up strategies to improve school districts, top-down is clearly losing. Many district leaders are reluctant to champion improvement for fear of being labeled with the epithet "top-down leader," the unkindest cut of all. In this article, the author presents the change processes in three…

  14. Inorganic Molecules; A Visual Database

    NSDL National Science Digital Library

    Inorganic Molecules: A Visual Data Base contains text and graphics describing 66 molecules and ions commonly used as examples in general chemistry courses. For each molecule, fifteen molecular properties are presented visually by eight or nine different molecular models created by the CAChe Scientific Molecular Modeling program.

  15. Top Quark Studies at D0

    E-print Network

    R. Y. Peters

    2014-08-10

    Years after its discovery in 1995 by CDF and D0, the top quark still undergoes intense investigations at the Tevatron. Using up to the full Run~II data sample, new measurements of top quark production and properties by the D0 Collaboration are presented. In particular, the first observation of single top quark s-channel production, the measurement of differential ttbar distributions, forward-backward ttbar asymmetry, a new measurement of the top quark mass, and a measurement of the top quark charge are discussed.

  16. Top Quark Mass Measurements at the Tevatron

    SciTech Connect

    Ye, Zhenyu; /Fermilab

    2011-07-01

    We report the latest results on the top-quark mass and on the top-antitop mass difference from the CDF and D0 collaborations using data collected at the Fermilab Tevatron p{bar p} collider at {radical}s = 1.96 TeV. We discuss general issues in top-quark mass measurements and present new results from direct measurements and from top-pair production cross-section. We also report new results on the top-antitop mass difference.

  17. Top Quark Physics at the Tevatron

    E-print Network

    Frederic Deliot; Douglas Glenzinski

    2011-10-10

    We review the field of top-quark physics with an emphasis on experimental techniques. The role of the top quark in the Standard Model of particle physics is summarized and the basic phenomenology of top-quark production and decay is introduced. We discuss how contributions from physics beyond the Standard Model could affect top-quark properties or event samples. The many measurements made at the Fermilab Tevatron, which test the Standard Model predictions or probe for direct evidence of new physics using the top-quark event samples, are reviewed here.

  18. Top physics at LHC with ttbar events

    E-print Network

    F. Hubaut

    2006-05-10

    The new CERN proton-proton collider, the LHC, is about to start in 2007 its data taking. Millions of top quarks will be available out of these data, allowing to perform a wide range of precision measurements and searches for new physics. An overview of the planned top physics program accessible with ttbar events is given for the ATLAS and CMS experiments. A particular emphasis is put on the precision measurements of the top mass, top polarization and searches for new physics in top production and decay.

  19. LHC limits on the top-Higgs in models with strong top-quark dynamics

    SciTech Connect

    Chivukula, R. Sekhar; Simmons, Elizabeth H.; Coleppa, Baradhwaj; Logan, Heather E.; Martin, Adam [Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Ottawa-Carleton Institute for Physics, Carleton University, Ottawa, Ontario K1S 5B6 (Canada); Theoretical Physics Department, Fermilab, Batavia, Illinois 60510 (United States)

    2011-11-01

    LHC searches for the standard model Higgs boson in WW or ZZ decay modes place strong constraints on the top-Higgs state predicted in many models with new dynamics preferentially affecting top quarks. Such a state couples strongly to top quarks, and is therefore produced through gluon fusion at a rate enhanced relative to the rate for the standard model Higgs boson. A top-Higgs state with mass less than 300 GeV is excluded at 95% C.L. if the associated top-pion has a mass of 150 GeV, and the constraint is even stronger if the mass of the top-pion state exceeds the top-quark mass or if the top-pion decay constant is a substantial fraction of the weak scale. These results have significant implications for theories with strong top dynamics, such as topcolor-assisted technicolor, top-seesaw models, and certain Higgsless models.

  20. A naturally light Higgs without light Top Partners

    E-print Network

    Adrian Carmona; Florian Goertz

    2015-05-12

    We demonstrate that the inclusion of a realistic lepton sector can relax significantly the upper bound on top partner masses in minimal composite Higgs models, induced by the lightness of the Higgs boson. To that extend, we present a comprehensive survey of the impact of different realizations of the fermion sectors on the Higgs potential, with a special emphasis on the role of the leptons. The non-negligible compositeness of the $\\tau_R$ in a general class of models that address the flavor structure of the lepton sector and the smallness of the corresponding FCNCs, can have a significant effect on the potential. We find that, with the $\\tau_R$ in the symmetric representation of $SO(5)$, an increase in the maximally allowed mass of the lightest top partner of $\\gtrsim 1$ TeV is possible for minimal quark setups like the MCHM$_{5,10}$, without increasing the tuning. A light Higgs boson $m_H \\sim(100-200)$ GeV is a natural prediction of such models, which thus provide a new setup that can evade ultra-light top partners without ad-hoc tuning in the Higgs mass. Moreover, we advocate a more minimal realization of the lepton sector than generally used in the literature, which still can avoid light partners due to its contributions to the Higgs mass in a different and very natural way, triggered by the seesaw mechanism. This allows to construct the most economical $SO(5)/SO(4)$ composite Higgs models possible. Using both a transparent 4D approach, as well as presenting numerical results in the 5D holographic description, we demonstrate that, including leptons, minimality and naturalness do not imply light partners. Leptonic effects, not considered before, could hence be crucial for the viability of composite models.

  1. The Top American Research Universities 2001

    NSDL National Science Digital Library

    2001-01-01

    An updated version of The Top American Research Universities has been released from Florida-based research organization, The Center, which creates this report annually. (The first edition of the Top American Research Universities was included in the July 28, 2000 Scout Report.) Institutions considered "top" are those that have federal research expenditures as reported to NSF of at least $20 million and that fall within the top 25 on at least one of The Center's nine measures (total research expenditures, federal research expenditures, endowment assets, annual giving, faculty members in the National Academies, faculty awards, doctoral degrees, postdoctoral appointees, and entering freshmen SAT scores). This year, the study has been expanded to include national rankings and to include institutions ranked in the top 26-50 (in addition to those ranked in top 25). The data are available in .pdf or spreadsheet (.xls) format. Interestingly, the top ten are all private universities.

  2. Electroweak Physics in Molecules

    NASA Astrophysics Data System (ADS)

    Deveney, E.; Paolino, R.; Kozlov, M. G.; Barry, J.; Cahn, S. B.; Murphree, D.; Rahmlow, D.; Steinecker, M.; Yale, C. G.; Demille, D.

    2009-05-01

    We report on recent progress of our program to measure nuclear spin-dependent parity nonconservation (NSD-PNC) in electron-nucleon interactions. We probe enhanced NSD-PNC signals from the mixing of rotational/hyperfine states in diatomic molecules that are Zeeman shifted to near degeneracy. The NSD-PNC effect arises from two main sources: the electron-vector/nucleon-axial ( VeAn ) tree-level neutral current (a Z^0-mediated coupling parameterized by electroweak constants C 2P,N ), and a hyperfine term resulting from coupling of the nuclear anapole moment (a magnetic moment induced by intra-nuclear electoweak interactions) to the electron's magnetic dipole moment. The VeAn term is independ. of the nucleon number A of a given nucleus and is suppressed in the Standard Model, while the anapole term scales as A^0.5ex2-0.1em/-0.15em0.25ex3making it the dominant source of NSD-PNC in nuclei withA>20. Measurements in molecules containing nuclei over a large range of A should allow us to disentangle the two NSD-PNC contributions, increasing available data on nuclear anapole moments and reducing uncertainties in current measurements of C2P and C2N. Progress includes demonstration of an increased-flux molecular beam source, and a substantial improvement of molecular detection efficiency using a new scheme.

  3. Table-top job analysis

    SciTech Connect

    Not Available

    1994-12-01

    The purpose of this Handbook is to establish general training program guidelines for training personnel in developing training for operation, maintenance, and technical support personnel at Department of Energy (DOE) nuclear facilities. TTJA is not the only method of job analysis; however, when conducted properly TTJA can be cost effective, efficient, and self-validating, and represents an effective method of defining job requirements. The table-top job analysis is suggested in the DOE Training Accreditation Program manuals as an acceptable alternative to traditional methods of analyzing job requirements. DOE 5480-20A strongly endorses and recommends it as the preferred method for analyzing jobs for positions addressed by the Order.

  4. Top transport in electroweak baryogenesis

    E-print Network

    Lars Fromme; Stephan J. Huber

    2006-05-09

    In non-supersymmetric models of electroweak baryogenesis the top quark plays a crucial role. Its CP-violating source term can be calculated in the WKB approximation. We point out how to resolve certain discrepancies between computations starting from the Dirac equation and the Schwinger--Keldysh formalism. We also improve on the transport equations, keeping the W-scatterings at finite rate. We apply these results to a model with one Higgs doublet, augmented by dimension-6 operators, where our refinements lead to an increase in the baryon asymmetry by a factor of up to about 5.

  5. A NOTE ON THE COMPOSITION PRODUCT OF SYMMETRIC MICHAEL CHING

    E-print Network

    Ching, Michael

    sequences, it has enough structure, namely that of a `normal oplax' monoidal product, to be able to defineA NOTE ON THE COMPOSITION PRODUCT OF SYMMETRIC SEQUENCES MICHAEL CHING Abstract. We consider the composition product of symmetric sequences in the case where the underlying symmetric monoidal structure does

  6. Computational Soundness for Key Exchange Protocols with Symmetric Encryption

    E-print Network

    Computational Soundness for Key Exchange Protocols with Symmetric Encryption Ralf K¨usters and Max, for the case of active adversaries and protocols that use symmetric encryption computational soundness has exchange protocols with symmetric encryption, along the lines of a paper by Canetti and Herzog on protocols

  7. Invertible Symmetric 3 3 Binary Matrices and GQ(2, 4)

    E-print Network

    Paris-Sud XI, Université de

    Invertible Symmetric 3 × 3 Binary Matrices and GQ(2, 4) Andrea Blunck,1 P´eter L´evay,2 Metod of 27 (disregarding the identity) invertible symmetric 3 × 3 matrices over GF(2) and the points of invertible symmetric 3 × 3 matrices over the field GF(2) has 28 elements. The elements different from

  8. A Uniform Description of Riemannian Symmetric Spaces as Grassmannians Using

    E-print Network

    Leung, Naichung Conan

    A Uniform Description of Riemannian Symmetric Spaces as Grassmannians Using Magic Square HUANG;Symmetric Spaces as Grassmannians Using Magic Square 1 Abstract In this thesis we introduce and study the (i description of all symmetric spaces. This is analogous to Tits magic square description for simple Lie

  9. Creation of Functional Micro/Nano Systems through Top-down and Bottom-up Approaches

    PubMed Central

    Wong, Tak-Sing; Brough, Branden; Ho, Chih-Ming

    2009-01-01

    Mimicking nature’s approach in creating devices with similar functional complexity is one of the ultimate goals of scientists and engineers. The remarkable elegance of these naturally evolved structures originates from bottom-up self-assembly processes. The seamless integration of top-down fabrication and bottom-up synthesis is the challenge for achieving intricate artificial systems. In this paper, technologies necessary for guided bottom-up assembly such as molecular manipulation, molecular binding, and the self assembling of molecules will be reviewed. In addition, the current progress of synthesizing mechanical devices through top-down and bottom-up approaches will be discussed. PMID:19382535

  10. Single-molecule diodes with high rectification ratios through environmental control.

    PubMed

    Capozzi, Brian; Xia, Jianlong; Adak, Olgun; Dell, Emma J; Liu, Zhen-Fei; Taylor, Jeffrey C; Neaton, Jeffrey B; Campos, Luis M; Venkataraman, Latha

    2015-06-01

    Molecular electronics aims to miniaturize electronic devices by using subnanometre-scale active components. A single-molecule diode, a circuit element that directs current flow, was first proposed more than 40?years ago and consisted of an asymmetric molecule comprising a donor-bridge-acceptor architecture to mimic a semiconductor p-n junction. Several single-molecule diodes have since been realized in junctions featuring asymmetric molecular backbones, molecule-electrode linkers or electrode materials. Despite these advances, molecular diodes have had limited potential for applications due to their low conductance, low rectification ratios, extreme sensitivity to the junction structure and high operating voltages. Here, we demonstrate a powerful approach to induce current rectification in symmetric single-molecule junctions using two electrodes of the same metal, but breaking symmetry by exposing considerably different electrode areas to an ionic solution. This allows us to control the junction's electrostatic environment in an asymmetric fashion by simply changing the bias polarity. With this method, we reliably and reproducibly achieve rectification ratios in excess of 200 at voltages as low as 370?mV using a symmetric oligomer of thiophene-1,1-dioxide. By taking advantage of the changes in the junction environment induced by the presence of an ionic solution, this method provides a general route for tuning nonlinear nanoscale device phenomena, which could potentially be applied in systems beyond single-molecule junctions. PMID:26005998

  11. Single-molecule diodes with high rectification ratios through environmental control

    NASA Astrophysics Data System (ADS)

    Capozzi, Brian; Xia, Jianlong; Adak, Olgun; Dell, Emma J.; Liu, Zhen-Fei; Taylor, Jeffrey C.; Neaton, Jeffrey B.; Campos, Luis M.; Venkataraman, Latha

    2015-06-01

    Molecular electronics aims to miniaturize electronic devices by using subnanometre-scale active components. A single-molecule diode, a circuit element that directs current flow, was first proposed more than 40?years ago and consisted of an asymmetric molecule comprising a donor–bridge–acceptor architecture to mimic a semiconductor p–n junction. Several single-molecule diodes have since been realized in junctions featuring asymmetric molecular backbones, molecule–electrode linkers or electrode materials. Despite these advances, molecular diodes have had limited potential for applications due to their low conductance, low rectification ratios, extreme sensitivity to the junction structure and high operating voltages. Here, we demonstrate a powerful approach to induce current rectification in symmetric single-molecule junctions using two electrodes of the same metal, but breaking symmetry by exposing considerably different electrode areas to an ionic solution. This allows us to control the junction's electrostatic environment in an asymmetric fashion by simply changing the bias polarity. With this method, we reliably and reproducibly achieve rectification ratios in excess of 200 at voltages as low as 370?mV using a symmetric oligomer of thiophene-1,1-dioxide. By taking advantage of the changes in the junction environment induced by the presence of an ionic solution, this method provides a general route for tuning nonlinear nanoscale device phenomena, which could potentially be applied in systems beyond single-molecule junctions.

  12. Propagation and transformation of flat-topped multi-Gaussian beams in a general nonsymmetrical apertured double-lens system

    Microsoft Academic Search

    Jiannong Chen

    2007-01-01

    On the basis of expanding a hard-edged aperture function as a finite sum of complex Gaussian functions, an approximate analytical expression for the propagation of an input complex amplitude distribution passing through a general nonsymmetrical apertured double-lens system is derived. Then, the propagation result for two-dimensional flat-topped multi-Gaussian beams is given. It is shown that the apertured Lohmann's symmetrical double-lens

  13. Cusped Wilson lines in symmetric representations

    E-print Network

    Correa, Diego H; Trancanelli, Diego

    2015-01-01

    We study the cusped Wilson line operators and Bremsstrahlung functions associated to particles transforming in the rank-$k$ symmetric representation of the gauge group $U(N)$ for ${\\cal N} = 4$ super Yang-Mills. We find the holographic D3-brane description for Wilson loops with internal cusps in two different limits: small cusp angle and $k\\sqrt{\\lambda}\\gg N$. This allows for a non-trivial check of a conjectured relation between the Bremsstrahlung function and the expectation value of the 1/2 BPS circular loop in the case of a representation other than the fundamental. Moreover, we observe that in the limit of $k\\gg N$, the cusped Wilson line expectation value is simply given by the exponential of the 1-loop diagram. Using group theory arguments, this eikonal exponentiation is conjectured to take place for all Wilson loop operators in symmetric representations with large $k$, independently of the contour on which they are supported.

  14. Binary switching in a ‘symmetric' potential landscape

    PubMed Central

    Roy, Kuntal; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha

    2013-01-01

    A binary switch is the basic building block for information processing. The potential energy profile of a bistable binary switch is a ‘symmetric' double well. The traditional method of switching it from one state (one well) to the other is to tilt the profile towards the desired state. Here, we present a case, where no such tilting is necessary to switch successfully, even in the presence of thermal noise. This happens because of the built-in dynamics inside the switch itself. It differs from the general perception on binary switching that in a ‘symmetric' potential landscape, the switching probability is 50% in the presence of thermal noise. Our results, considering the complete three-dimensional potential landscape, demonstrate intriguing phenomena on binary switching mechanism. With experimentally feasible parameters, we theoretically demonstrate such intriguing possibility in electric field induced magnetization switching of a shape-anisotropic single-domain magnetostrictive nanomagnet with two stable states at room-temperature. PMID:24154561

  15. Cusped Wilson lines in symmetric representations

    E-print Network

    Diego H. Correa; Fidel I. Schaposnik Massolo; Diego Trancanelli

    2015-06-04

    We study the cusped Wilson line operators and Bremsstrahlung functions associated to particles transforming in the rank-$k$ symmetric representation of the gauge group $U(N)$ for ${\\cal N} = 4$ super Yang-Mills. We find the holographic D3-brane description for Wilson loops with internal cusps in two different limits: small cusp angle and $k\\sqrt{\\lambda}\\gg N$. This allows for a non-trivial check of a conjectured relation between the Bremsstrahlung function and the expectation value of the 1/2 BPS circular loop in the case of a representation other than the fundamental. Moreover, we observe that in the limit of $k\\gg N$, the cusped Wilson line expectation value is simply given by the exponential of the 1-loop diagram. Using group theory arguments, this eikonal exponentiation is conjectured to take place for all Wilson loop operators in symmetric representations with large $k$, independently of the contour on which they are supported.

  16. A parallel solution for the symmetric Eigenproblem

    NASA Technical Reports Server (NTRS)

    Thurston, Gaylen A.

    1987-01-01

    A completely parallel algorithm for the symmetric eigenproblem AX = Lambda BX is outlined. The algorithm is parallel in the sense that the numerical operations do not occur in a fixed sequence. Therefore, a large number of operations can be programmed to be performed concurrently on a computer with multiple central processing units. The standard symmetric eigenvalue problem AX = Lambda X has the property that the n eigenvalues of the principal submatrix of A of order n are separated by the (n-1) eignvalues of the principal submatrix of order (n-1). The separation property delineated n intervals containing one eigenvalue. Each eigenvalue and corresponding eigenvector can be computed independently. The n eigenproblem calculations can be divided among multiple processing units.

  17. Error correction and symmetrization in quantum computers

    E-print Network

    Peres, A

    1996-01-01

    Errors in quantum computers are of two kinds: sudden perturbations to isolated qubits, and slow random drifts of all the qubits. The latter may be reduced, but not eliminated, by means of symmetrization, namely by using many replicas of the computer, and forcing their joint quantum state to be completely symmetric. On the other hand, isolated errors can be corrected by quantum codewords that represent a logical qubit in a redundant way, by several physical qubits. If one of the physical qubits is perturbed, for example if it gets entangled with an unknown environment, there still is enough information encoded in the other physical qubits to restore the logical qubit, and disentangle it from the environment. The recovery procedure may consist of unitary operations, without the need of actually identifying the error.

  18. Error correction and symmetrization in quantum computers

    E-print Network

    Asher Peres

    1996-11-26

    Errors in quantum computers are of two kinds: sudden perturbations to isolated qubits, and slow random drifts of all the qubits. The latter may be reduced, but not eliminated, by means of symmetrization, namely by using many replicas of the computer, and forcing their joint quantum state to be completely symmetric. On the other hand, isolated errors can be corrected by quantum codewords that represent a logical qubit in a redundant way, by several physical qubits. If one of the physical qubits is perturbed, for example if it gets entangled with an unknown environment, there still is enough information encoded in the other physical qubits to restore the logical qubit, and disentangle it from the environment. The recovery procedure may consist of unitary operations, without the need of actually identifying the error.

  19. Molecular docking guided structure based design of symmetrical N,N'-disubstituted urea/thiourea as HIV-1 gp120-CD4 binding inhibitors.

    PubMed

    Sivan, Sree Kanth; Vangala, Radhika; Manga, Vijjulatha

    2013-08-01

    Induced fit molecular docking studies were performed on BMS-806 derivatives reported as small molecule inhibitors of HIV-1 gp120-CD4 binding. Comprehensive study of protein-ligand interactions guided in identification and design of novel symmetrical N,N'-disubstituted urea and thiourea as HIV-1 gp120-CD4 binding inhibitors. These molecules were synthesized in aqueous medium using microwave irradiation. Synthesized molecules were screened for their inhibitory ability by HIV-1 gp120-CD4 capture enzyme-linked immunosorbent assay (ELISA). Designed compounds were found to inhibit HIV-1 gp120-CD4 binding in micromolar (0.013-0.247 ?M) concentrations. PMID:23777826

  20. Thiolation of symmetrical and unsymmetrical diketopiperazines.

    PubMed

    Ruff, Bettina M; Zhong, Sabilla; Nieger, Martin; Bräse, Stefan

    2012-02-01

    The introduction of sulfur units into a variety of symmetrical and unsymmetrical diketopiperazines (DKPs) is described. We investigated different thiolation methods utilizing several bases and electrophilic sulfur reagents, leading to monomethylthio-, bis(methylthio)-, and epithio-DKPs. Their formation proceeded diastereoselectively, facilitating the application in total syntheses of many thiodiketopiperazine (TDKP) natural products. Furthermore, possible side reactions as well as mechanistic studies and stereochemical structural assignments of the obtained products are given. PMID:22183416

  1. Solitons in PT-symmetric nonlinear lattices

    SciTech Connect

    Abdullaev, Fatkhulla Kh.; Konotop, Vladimir V.; Zezyulin, Dmitry A. [Centro de Fisica Teorica e Computacional, Faculdade de Ciencias, Universidade de Lisboa, Avenida Professor Gama Pinto 2, P-1649-003 Lisboa (Portugal); Kartashov, Yaroslav V. [ICFO-Institut de Ciencies Fotoniques, and Universitat Politecnica de Catalunya, Mediterranean Technology Park, E-08860 Castelldefels, Barcelona (Spain)

    2011-04-15

    The existence of localized modes supported by the PT-symmetric nonlinear lattices is reported. The system considered reveals unusual properties: unlike other typical dissipative systems, it possesses families (branches) of solutions, which can be parametrized by the propagation constant; relatively narrow localized modes appear to be stable, even when the conservative nonlinear lattice potential is absent; and finally, the system supports stable multipole solutions.

  2. On the Symmetric Negabent Boolean Functions

    Microsoft Academic Search

    Sumanta Sarkar

    2009-01-01

    We study the negabent Boolean functions which are symmetric. The Boolean function which has equal absolute spectral values\\u000a under the nega-Hadamard transform is called a negabent function. For a bent function, the absolute spectral values are the\\u000a same under the Hadamard-Walsh transform. Unlike bent functions, negabent functions can exist on odd number of variables. Moreover,\\u000a all the affine functions are

  3. Zero Knowledge and Soundness Are Symmetric

    Microsoft Academic Search

    Shien Jin Ong; Salil P. Vadhan

    2007-01-01

    We give a complexity-theoretic characterization of the class of problems in NP having zero-knowledge argument systems. This char- acterization is symmetric in its treatment of the zero knowledge and the soundness conditions, and thus we deduce that the class of prob- lems in NP \\\\ coNP having zero-knowledge arguments is closed under complement. Furthermore, we show that a problem in

  4. Irreducible complexity of iterated symmetric bimodal maps

    E-print Network

    J. P. Lampreia; R. Severino; J. Sousa Ramos

    2004-03-08

    We introduce a tree structure for the iterates of symmetric bimodal maps and identify a subset which we prove to be isomorphic to the family of unimodal maps. This subset is used as a second factor for a $\\ast $-product that we define in the space of bimodal kneading sequences. Finally, we give some properties for this product and study the *-product induced on the associated Markov shifts.

  5. Irreducible complexity of iterated symmetric bimodal maps

    Microsoft Academic Search

    J. P. Lampreia; R. Severino; J. Sousa Ramos

    2004-01-01

    We introduce a tree structure for the iterates of symmetric bimodal maps and\\u000aidentify a subset which we prove to be isomorphic to the family of unimodal\\u000amaps. This subset is used as a second factor for a $\\\\ast $-product that we\\u000adefine in the space of bimodal kneading sequences. Finally, we give some\\u000aproperties for this product and study

  6. Symmetric corticobasal degeneration (S-CBD)

    PubMed Central

    Hassan, Anhar; Boeve, Bradley F.; Whitwell, Jennifer L.; Jack, Clifford R; Parisi, Joseph E.; Dickson, Dennis W.; Josephs, Keith A.

    2010-01-01

    Background Corticobasal degeneration (CBD) is a neurodegenerative disease characterized pathologically by neuronal loss, gliosis and tau deposition in neocortex, basal ganglia and brainstem. Typical clinical presentation is known as corticobasal syndrome (CBS) and involves the core features of progressive asymmetric rigidity and apraxia, accompanied by other signs of cortical and extrapyramidal dysfunction. Asymmetry is also emphasized on neuroimaging. Objective To describe a series of cases of CBD with symmetric clinical features and to compare clinical and imaging features of these symmetric CBD cases (S-CBD) to typical cases of CBS with CBD pathology. Methods All cases of pathologically confirmed CBD from the Mayo Clinic Rochester database were identified. Clinical records were reviewed and quantitative volumetric analysis of symmetric atrophy on head MRI using atlas based parcellation was performed. Subjects were classified as S-CBD if no differences had been observed between right- and left-sided cortical or extrapyramidal signs or symptoms. S-CBD cases were compared to 10 randomly selected typical CBS cases. Results Five cases (2 female) met criteria for S-CBD. None had limb dystonia, myoclonus, apraxia or alien limb phenomena. S-CBD cases had significantly less asymmetric atrophy when compared with CBS cases (p=0.009); they were also younger at onset (median 61 versus 66 years, p<0.05) and death (67 versus 73 years, p<0.05). Family history was present in 40% of S-CBD cases. Conclusions CBD can have a symmetric presentation, clinically and radiologically, in which typical features of CBS, such as limb apraxia, myoclonus, dystonia and alien limb phenomenon, may be absent. PMID:20018548

  7. Symmetric vertex models on planar random graphs

    Microsoft Academic Search

    D. A. Johnston

    1999-01-01

    We solve a 4-(bond)-vertex model on an ensemble of 3-regular (?3) planar random graphs, which has the effect of coupling the vertex model to 2D quantum gravity. The method of solution, by mapping onto an Ising model in field, is inspired by the solution by Wu et.al. of the regular lattice equivalent – a symmetric 8-vertex model on the honeycomb

  8. Symmetric vertex models on planar random graphs

    Microsoft Academic Search

    D. A. Johnston

    1999-01-01

    We solve a 4-(bond)-vertex model on an ensemble of 3-regular (Phi3) planar random graphs, which has the effect of coupling the vertex model to 2D quantum gravity. The method of solution, by mapping onto an Ising model in field, is inspired by the solution by Wu et.al. of the regular lattice equivalent - a symmetric 8-vertex model on the honeycomb

  9. Center-symmetric 1/N expansion

    SciTech Connect

    Schaden, Martin [Department of Physics, Rutgers University in Newark, 365 Smith Hall, 101 Warren Street, Newark, New Jersey 07102 (United States)

    2005-05-15

    The free energy of U(N) gauge theory is expanded about a center-symmetric topological background configuration with vanishing action and vanishing Polyakov loops. We construct this background for SU(N) lattice gauge theory and show that it uniquely describes center-symmetric minimal action orbits in the limit of infinite lattice volume. The leading contribution to the free energy in the 1/N expansion about this background is of O(N{sup 0}) rather than O(N{sup 2}) as one finds when the center symmetry is spontaneously broken. The contribution of planar 't Hooft diagrams to the free energy is O(1/N{sup 2}) and subleading in this case. The change in behavior of the diagrammatic expansion is traced to Linde's observation that the usual perturbation series of non-Abelian gauge theories suffers from severe infrared divergences [A. Linde, Phys. Lett. B 96, 289 (1980).]. This infrared problem does not arise in a center-symmetric expansion. The 't Hooft coupling {lambda}=g{sup 2}N is found to decrease {proportional_to}1/ln(N) for large N. There is evidence of a vector-ghost in the planar truncation of the model.

  10. Universal horizons in maximally symmetric spaces

    E-print Network

    Jishnu Bhattacharyya; David Mattingly

    2014-08-27

    Universal horizons in Ho\\v{r}ava-Lifshitz gravity and Einstein-{\\ae}ther theory are the equivalent of causal horizons in general relativity and appear to have many of the same properties, including a first law of horizon thermodynamics and thermal radiation. Since universal horizons are infrared solutions of a putative power counting renormalizable quantum gravitational theory, fully understanding their thermodynamics will shed light on the interplay between black hole thermodynamics and quantum gravity. In this paper, we provide a complete classification, including asymptotic charges, of all four dimensional static and spherically symmetric universal horizon solutions with maximally symmetric asymptotics -- the equivalents of the Schwarzschild, Schwarzschild de Sitter or Schwarzschild anti-de Sitter spacetimes. Additionally we derive the associated first laws for the universal horizon solutions. Finally we prove that independent of asymptotic boundary conditions, any spherically symmetric solution in Ho\\v{r}ava-Lifshitz gravity with a universal horizon is also a solution of Einstein-{\\ae}ther theory, thereby broadening and complementing the known equivalence region of the solution spaces.

  11. Super-symmetric informationally complete measurements

    E-print Network

    Huangjun Zhu

    2014-12-02

    Symmetric informationally complete measurements (SICs in short) are highly symmetric structure in the Hilbert space. They possess many nice properties which render them an ideal candidate of fiducial measurements. The symmetry of SICs is intimately connected with the geometry of the quantum state space and also has profound implications for foundational studies. Here we study those SICs that are most symmetric according to a natural criterion and show that all of them are covariant with respect to the Heisenberg-Weyl groups, which are characterized by the discrete analog of the canonical commutation relation. Moreover, their symmetry groups are subgroups of the Clifford groups. In particular, we prove that the SIC in dimension~2, the Hesse SIC in dimension~3, and the set of Hoggar lines in dimension~8 are the only three SICs up to unitary equivalence whose symmetry groups act transitively on pairs of SIC projectors. Our work is of intrinsic interest to studying the geometry of quantum state space and foundational issues entangled with the geometry.

  12. ?to e in R-symmetric Supersymmetry

    E-print Network

    Ricky Fok; Graham D. Kribs

    2010-11-23

    We demonstrate that mu/e slepton mixing is significantly more restricted than previously thought within the already remarkably flavor-safe R-symmetric supersymmetric standard model. We calculate bounds from mu to e gamma, mu to 3e and, most importantly, mu to e conversion. The process mu to e conversion is significantly more restrictive in R-symmetric models since this process can occur through operators that do not require a chirality-flip. We delineate the allowed parameter space, demonstrating that maximal mixing is rarely possible with weak scale superpartners, while O(0.1) mixing is permitted within most of the space. The best approach to find or rule out mu/e mixing in R-symmetric supersymmetric models is a multi-pronged attack looking at both mu to e conversion as well as mu to e gamma. The redundancy eliminates much of the parameter space where one process, but not both processes, contain amplitudes that accidentally destructively interfere. We briefly discuss implications for searches of slepton flavor violation at the LHC.

  13. Spherically Symmetric Thick Branes Cosmological Evolution

    E-print Network

    Alex E. Bernardini; R. T. Cavalcanti; Roldao da Rocha

    2014-11-13

    Spherically symmetric time-dependent solutions for the 5D system of a scalar field canonically coupled to gravity are obtained and identified as an extension of recent results obtained by Ahmed, Grzadkowskia and Wudkab. The corresponding cosmology of models with regularized branes generated by such a 5D scalar field scenario is also investigated. It has been shown that the anisotropic evolution of the warp factor and consequently the Hubble like parameter are both driven by the radial coordinate on the brane, which leads to an emergent thick brane-world scenario with spherically symmetric time dependent warp factor. Meanwhile, the separability of variables depending on fifth dimension, y, which is exhibited by the equations of motion, allows one to recover the extra dimensional profiles obtained in the literature, namely the extra dimensional part of the scale (warp) factor and the scalar field dependence on y. Therefore, our results are mainly concerned with the time dependence of a spherically symmetric warp factor. Besides evincing possibilities for obtaining asymmetric stable brane-world scenarios, the extra dimensional profiles here obtained can also be reduced to those ones investigated in the literature.

  14. The EPSILON experimental pseudo-symmetric trap

    NASA Astrophysics Data System (ADS)

    Arsenin, V. V.; Dlougach, E. D.; Kulygin, V. M.; Kuyanov, A. Yu.; Skovoroda, A. A.; Timofeev, A. V.; Zhil'tsov, V. A.; Zvonkov, A. V.

    2001-07-01

    Within the framework of the Adaptive Plasma Experiment (APEX) conceptual project, a trap with closed magnetic field lines, the Experimental Pseudo-Symmetric Closed Trap (EPSILON), is examined. The APEX project is aimed at theoretical and experimental development of the physical foundations for a steady state thermonuclear reactor designed on the basis of an alternative magnetic trap with tokamak-like large ? plasma confinement. A discussion is given of the fundamental principle of pseudo-symmetry, which a magnetic configuration with tokamak-like plasma confinement should satisfy. Examples are given of calculations in the paraxial approximation of pseudo-symmetric curvilinear elements with a poloidal modulus B isoline. The EPSILON trap, consisting of two direct axisymmetric mirrors linked by two curvilinear pseudo-symmetric elements, is considered. To increase the equilibrium ?, the plasma currents are short-circuited within curvilinear equilibrium elements. An untraditional scheme of MHD stabilization for a trap with closed field lines by use of axisymmetric mirrors with a divertor is analysed. The experimental installation EPSILON-One Mirror Element (OME), which is under construction for experimental investigation of stabilization by divertor, is discussed. The opportunity for applying the ECR method of plasma production in EPSILON-OME in conditions of high density and low magnetic field is examined.

  15. Forces in molecules.

    PubMed

    Hernández-Trujillo, Jesús; Cortés-Guzmán, Fernando; Fang, De-Chai; Bader, Richard F W

    2007-01-01

    Chemistry is determined by the electrostatic forces acting within a collection of nuclei and electrons. The attraction of the nuclei for the electrons is the only attractive force in a molecule and is the force responsible for the bonding between atoms. This is the attractive force acting on the electrons in the Ehrenfest force and on the nuclei in the Feynman force, one that is countered by the repulsion between the electrons in the former and by the repulsion between the nuclei in the latter. The virial theorem relates these forces to the energy changes resulting from interactions between atoms. All bonding, as signified by the presence of a bond path, has a common origin in terms of the mechanics determined by the Ehrenfest, Feynman and virial theorems. This paper is concerned in particular with the mechanics of interaction encountered in what are classically described as 'nonbonded interactions'--are atoms that 'touch' bonded or repelling one another? PMID:17328425

  16. Astrochemistry and Interstellar Molecules

    NASA Astrophysics Data System (ADS)

    Min, Y. C.

    2010-03-01

    Astrochemistry provides powerful tools to understand various cosmic phenomena, including those in our solar system to the large-scale structure of the universe. In addition, the chemical property of an astronomical body is a crucial factor which governs the evolution of the system. Recent progress in astrophysical theories, computational modelings, and observational techniques requires a detailed understanding of the interactions between the constituents of an astronomical system, which are atoms and molecules within the system. Especially the far-infrared/sub-millimeter wave range, which is called as the last frontier in astronomical observations, contains numerous molecular lines, which may provide a huge amount of new information. However, we need an astrochemical understanding to use this information fully. Although this review is very limited, I would like to stress the importance of astrochemical approach in this overview for the field, which is getting much more attention than ever before.

  17. Single molecule laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Atta, Diaa; Okasha, Ali

    2015-01-01

    In this article, we discussed some single molecule spectroscopy techniques and methods. We have chosen the simplicity in this survey based on our laboratory experience in this field. We concentrated on the imaging by both techniques the wide field and the scanning microscopes. Other imaging enhancements on the technique like extended resolution wide field, the total internal reflection imaging, and its derivatives are also reviewed. In addition to the imaging techniques, some diffusion techniques also are discussed like fluorescence correlation spectroscopy. The related methods like Forester resonance transfer, photo-induced electron transfer and anisotropy (steady state and time decay) are also discussed. In addition, we elucidated some simple details about the theory behind the FCS and its resulting curve fitting. This review is preceded by general introduction and ended with the conclusion.

  18. Emerging small molecule drugs.

    PubMed

    Colin, Sophie; Chinetti-Gbaguidi, Giulia; Kuivenhoven, Jan A; Staels, Bart

    2015-01-01

    Dyslipidaemia is a major risk factor for cardiovascular diseases. Pharmacological lowering of LDL-C levels using statins reduces cardiovascular risk. However, a substantial residual risk persists especially in patients with type 2 diabetes mellitus. Because of the inverse association observed in epidemiological studies of HDL-C with the risk for cardiovascular diseases, novel therapeutic strategies to raise HDL-C levels or improve HDL functionality are developed as complementary therapy for cardiovascular diseases. However, until now most therapies targeting HDL-C levels failed in clinical trials because of side effects or absence of clinical benefits. This chapter will highlight the emerging small molecules currently developed and tested in clinical trials to pharmacologically modulate HDL-C and functionality including new CETP inhibitors (anacetrapib, evacetrapib), novel PPAR agonists (K-877, CER-002, DSP-8658, INT131 and GFT505), LXR agonists (ATI-111, LXR-623, XL-652) and RVX-208. PMID:25523004

  19. Nanochannel Based Single Molecule Recycling

    PubMed Central

    Lesoine, John F.; Venkataraman, Prahnesh A.; Maloney, Peter C.; Dumont, Mark

    2012-01-01

    We present a method for measuring the fluorescence from a single molecule hundreds of times without surface immobilization. The approach is based on the use of electroosmosis to repeatedly drive a single target molecule in a fused silica nanochannel through a stationary laser focus. Single molecule fluorescence detected during the transit time through the laser focus is used to repeatedly reverse the electrical potential controlling the flow direction. Our method does not rely on continuous observation and therefore is less susceptible to fluorescence blinking than existing fluorescence-based trapping schemes. The variation in the turnaround times can be used to measure the diffusion coefficient on a single molecule level. We demonstrate the ability to recycle both proteins and DNA in nanochannels and show that the procedure can be combined with single-pair Förster energy transfer. Nanochannel-based single molecule recycling holds promise for studying conformational dynamics on the same single molecule in solution and without surface tethering. PMID:22662745

  20. Towards single molecule DNA sequencing

    NASA Astrophysics Data System (ADS)

    Liu, Hao

    Single molecule DNA Sequencing technology has been a hot research topic in the recent decades because it holds the promise to sequence a human genome in a fast and affordable way, which will eventually make personalized medicine possible. Single molecule differentiation and DNA translocation control are the two main challenges in all single molecule DNA sequencing methods. In this thesis, I will first introduce DNA sequencing technology development and its application, and then explain the performance and limitation of prior art in detail. Following that, I will show a single molecule DNA base differentiation result obtained in recognition tunneling experiments. Furthermore, I will explain the assembly of a nanofluidic platform for single strand DNA translocation, which holds the promised to be integrated into a single molecule DNA sequencing instrument for DNA translocation control. Taken together, my dissertation research demonstrated the potential of using recognition tunneling techniques to serve as a general readout system for single molecule DNA sequencing application.

  1. Uplift of symmetrical anchor plates by using grid-fixed reinforced reinforcement in cohesionless soil

    NASA Astrophysics Data System (ADS)

    Niroumand, Hamed; Kassim, Khairul Anuar

    2014-03-01

    Uplift response of symmetrical anchor plates with and without grid fixed reinforced (GFR) reinforcement was evaluated in model tests and numerical simulations by Plaxis. Many variations of reinforcement layers were used to reinforce the sandy soil over symmetrical anchor plates. In the current research, different factors such as relative density of sand, embedment ratios, and various GFR parameters including size, number of layers, and the proximity of the layer to the symmetrical anchor plate were investigated in a scale model. The failure mechanism and the associated rupture surface were observed and evaluated. GFR, a tied up system made of fiber reinforcement polymer (FRP) strips and end balls, was connected to the geosynthetic material and anchored into the soil. Test results showed that using GFR reinforcement significantly improved the uplift capacity of anchor plates. It was found that the inclusion of one layer of GFR, which rested directly on the top of the anchor plate, was more effective in enhancing the anchor capacity itself than other methods. It was found that by including GFR the uplift response was improved by 29%. Multi layers of GFR proved more effective in enhancing the uplift capacity than a single GFR reinforcement. This is due to the additional anchorage provided by the GFR at each level of reinforcement. In general, the results show that the uplift capacity of symmetrical anchor plates in loose and dense sand can be significantly increased by the inclusion of GFR. It was also observed that the inclusion of GFR reduced the requirement for a large L/D ratio to achieve the required uplift capacity. The laboratory and numerical analysis results are found to be in agreement in terms of breakout factor and failure mechanism pattern.

  2. Monte Carlo Simulations for Top Pair and Single Top Production at the Tevatron

    E-print Network

    U. Husemann

    2008-07-29

    Monte Carlo (MC) simulations are indispensable tools for top quark physics, both at the current Tevatron collider and the upcoming Large Hadron Collider. In this paper we review how the Tevatron experiments CDF and D0 utilize MC simulations for top quark analyses. We describe the standard MC generators used to simulate top quark pair and single top quark production, followed by a discussion of methods to extract systematic uncertainties of top physics results related to the MC generator choice. The paper also shows the special MC requirements for some example top properties measurements at the Tevatron.

  3. The "Top Priority" at the LHC

    E-print Network

    Tao Han

    2008-04-20

    The LHC will be a top-quark factory. With 80 million pairs of top quarks and an additional 34 million single tops produced annually at the designed high luminosity, the properties of this particle will be studied to a great accuracy. The fact that the top quark is the heaviest elementary particle in the Standard Model with a mass right at the electroweak scale makes it tempting to contemplate its role in electroweak symmetry breaking, as well as its potential as a window to unknown new physics at the TeV scale. We summarize the expectations for top-quark physics at the LHC, and outline new physics scenarios in which the top quark is crucially involved.

  4. Top quark mass measurements at CDF

    SciTech Connect

    Brubaker, Erik; /Chicago U., EFI

    2006-05-01

    The mass of the top quark M{sub top} is interesting both as a fundamental parameter of the standard model and as an important input to precision electroweak tests. The Collider Detector at Fermilab (CDF) has a robust program of top quark mass analyses, including the most precise single measurement, M{sub top} = 173.4 {+-} 2.8 GeV/c{sup 2}, using 680 pb{sup -1} of p{bar p} collision data. A combination of current results from CDF gives M{sub top} = 172.0 {+-} 2.7 GeV/c{sup 2}, surpassing the stated goal of 3 GeV/c{sup 2} precision using 2 fb{sup -1} of data. Finally, a combination with current D0 results gives a world average top quark mass of 172.5 {+-} 2.3 GeV/c{sup 2}.

  5. Top-down Proteomics in Health and Disease: Challenges and Opportunities

    PubMed Central

    Gregorich, Zachery R.; Ge, Ying

    2014-01-01

    Proteomics is essential for deciphering how molecules interact as a system and for understanding the functions of cellular systems in human disease; however, the unique characteristics of the human proteome, which include a high dynamic range of protein expression and extreme complexity due to a plethora of post-translational modifications (PTMs) and sequence variations, make such analyses challenging. An emerging “top-down” mass spectrometry (MS)-based proteomics approach, which provides a “bird’s eye” view of all proteoforms, has unique advantages for the assessment of PTMs and sequence variations. Recently, a number of studies have showcased the potential of top-down proteomics for unraveling of disease mechanisms and discovery of new biomarkers. Nevertheless, the top-down approach still faces significant challenges in terms of protein solubility, separation, and the detection of large intact proteins, as well as the under-developed data analysis tools. Consequently, new technological developments are urgently needed to advance the field of top-down proteomics. Herein, we intend to provide an overview of the recent applications of top-down proteomics in biomedical research. Moreover, we will outline the challenges and opportunities facing top-down proteomics strategies aimed at understanding and diagnosing human diseases. PMID:24723472

  6. Aromatic molecules as spintronic devices

    SciTech Connect

    Ojeda, J. H., E-mail: judith.ojeda@uptc.edu.co [Instituto de Alta investigación, Universidad de Tarapacá, Casilla 7D Arica (Chile); Grupo de Física de Materiales, Universidad Pedagógica y Tecnológica de Colombia, Tunja (Colombia); Orellana, P. A. [Departamento de Física, Universidad Técnica Federico Santa María, Casilla 110-V, Valparaíso (Chile)] [Departamento de Física, Universidad Técnica Federico Santa María, Casilla 110-V, Valparaíso (Chile); Laroze, D. [Instituto de Alta investigación, Universidad de Tarapacá, Casilla 7D Arica (Chile)] [Instituto de Alta investigación, Universidad de Tarapacá, Casilla 7D Arica (Chile)

    2014-03-14

    In this paper, we study the spin-dependent electron transport through aromatic molecular chains attached to two semi-infinite leads. We model this system taking into account different geometrical configurations which are all characterized by a tight binding Hamiltonian. Based on the Green's function approach with a Landauer formalism, we find spin-dependent transport in short aromatic molecules by applying external magnetic fields. Additionally, we find that the magnetoresistance of aromatic molecules can reach different values, which are dependent on the variations in the applied magnetic field, length of the molecules, and the interactions between the contacts and the aromatic molecule.

  7. Top quark mass: past, present and future

    SciTech Connect

    Gutierrez, Gaston; /Fermilab

    2007-07-01

    The top quark is the most massive elementary particle discovered thus far. Its large mass may help explain the mechanism by which fundamental particles gain mass - the Standard Model's greatest standing mystery. Today the top quark mass, together with the W boson mass, plays an important role in constraining the Higgs boson mass. The current status of the top quark mass measurement and a brief outline of the expectation at the Large Hadron Collider and the International Linear Collider will be covered.

  8. MHD Integrated Topping Cycle Project

    SciTech Connect

    Not Available

    1992-07-01

    This seventeenth quarterly technical progress report of the MHD Integrated Topping Cycle Project presents the accomplishments during the period August 1, 1991 to October 31, 1991. Manufacturing of the prototypical combustor pressure shell has been completed including leak, proof, and assembly fit checking. Manufacturing of forty-five cooling panels was also completed including leak, proof, and flow testing. All precombustor internal components (combustion can baffle and swirl box) were received and checked, and integration of the components was initiated. A decision was made regarding the primary and backup designs for the 1A4 channel. The assembly of the channel related prototypical hardware continued. The cathode wall electrical wiring is now complete. The mechanical design of the diffuser has been completed.

  9. Dielectric behavior of some small ketones as ideal polar molecules.

    PubMed

    Shikata, Toshiyuki; Yoshida, Nao

    2012-05-17

    The dielectric behaviors of some small symmetric ketone molecules, including acetone, 3-pentanone, cyclopentanone, 4-heptanone, and cyclohexanone, were investigated as a function of temperature (T) over a wide frequency range from 50 MHz (3.14 × 10(8) s(-1), in angular frequency) to 3 THz (1.88 × 10(13) s(-1)). The temperature dependencies of the rotational diffusion times (?(r)) determined using (17)O NMR spin-lattice relaxation time (T(1)) measurements and viscosities of the ketones were also examined. The obtained temperature dependencies of the parameters for the ketones were compared with those of ideal polar molecules, which obey the Stokes-Einstein-Debye (SED) relationship without the formation of intermolecular dimeric associations and without orientational correlations between dipoles (molecular axes), that is, free rotation. Kirkwood correlation factors (g(K)) of only acetone and 3-pentanone were close to unity over a wide temperature range, whereas those of other ketones were obviously less than unity. These results revealed that no correlations exist between the rotational motions of dipoles in acetone and 3-pentanone, as expected in ideal polar molecules. However, other ketones exhibited orientational correlations in their dipoles because of dipole-dipole interactions via antiparallel configurations. Furthermore, because acetone and 3-pentanone satisfied the SED relationship and because their microscopic dielectric relaxation times (?(?)), which were calculated from the determined dielectric relaxation times (?(D)) via the relationship ?(?) = ?(D)g(K)(-1), were identical to 3?(r) and were proportional to V?(k(B)T)(-1) over the wide temperature range examined, where V, k(B), and ? represent the effective molecular volume, Boltzmann's constant, and the viscosity of the liquid molecules, respectively, these two ketone molecules behave as ideal polar molecules. In addition, other ketones not significantly larger than acetone and 3-pentanone in molecular size likely form dimeric intermolecular associations with antiparallel cyclic configurations, which demonstrates the g(K) values less than unity. PMID:22530697

  10. Dispersion forces between molecules with one or both molecules excited

    Microsoft Academic Search

    E. A. Power; T. Thirunamachandran

    1995-01-01

    Dispersion energies between molecules involving one in an electronically excited state are calculated using fourth-order perturbation theory within the framework of the multipolar form of quantum electrodynamics. There are significant differences between the energies for these cases and those where both molecules are in their ground states. The calculations are performed within the electric-dipole approximation for the interaction of the

  11. Top Quark Physics at the CDF Experiment

    E-print Network

    Bernd Stelzer; for the CDF Collaboration

    2010-07-21

    Fermilab's Tevatron accelerator is recently performing at record luminosities that enables a program systematically addressing the physics of top quarks. The CDF collaboration has analyzed up to 5/fb of proton anti-proton collisions from the Tevatron at a center of mass energy of 1.96 TeV. The large datasets available allow to push top quark measurements to higher and higher precision and have lead to the recent observation of electroweak single top quark production at the Tevatron. This article reviews recent results on top quark physics from the CDF experiment.

  12. Top quark physics in hadron collisions

    E-print Network

    Wolfgang Wagner

    2007-08-03

    The top quark is the heaviest elementary particle observed to date. Its large mass makes the top quark an ideal laboratory to test predictions of perturbation theory concerning heavy quark production at hadron colliders. The top quark is also a powerful probe for new phenomena beyond the Standard Model of particle physics. In addition, the top quark mass is a crucial parameter for scrutinizing the Standard Model in electroweak precision tests and for predicting the mass of the yet unobserved Higgs boson. Ten years after the discovery of the top quark at the Fermilab Tevatron top quark physics has entered an era where detailed measurements of top quark properties are undertaken. In this review article an introduction to the phenomenology of top quark production in hadron collisions is given, the lessons learned in Tevatron Run I are summarized, and first Run II results are discussed. A brief outlook to the possibilities of top quark research a the Large Hadron Collider, currently under construction at CERN, is included.

  13. Single Top Quarks at the Tevatron

    E-print Network

    A. P. Heinson

    2008-09-05

    After many years searching for electroweak production of top quarks, the Tevatron collider experiments have now moved from obtaining first evidence for single top quark production to an impressive array of measurements that test the standard model in several directions. This paper describes measurements of the single top quark cross sections, limits set on the CKM matrix element |Vtb|, searches for production of single top quarks produced via flavor-changing neutral currents and from heavy W-prime and H+ boson resonances, and studies of anomalous Wtb couplings. It concludes with projections for future expected significance as the analyzed datasets grow.

  14. Single Top Quark Production at the Tevatron

    E-print Network

    Yvonne Peters; for the CDF; D0 Collaborations

    2012-10-26

    While the heaviest known elementary particle, the top quark, has been discovered in 1995 by the CDF and D0 collaborations in ttbar events, it took 14 more years until the observation of single top quark production. In this article, we discuss recent studies of single top quark production by the CDF and D0 collaborations at the Tevatron. In particular, we present the measurement of single top quark s- and t-channel production combined, the first observation of t-channel production, the simultaneous measurement of s- and t-channel production cross sections as well as the extraction of the CMK matrix element |Vtb}|.

  15. Adsorption of symmetric random copolymer onto symmetric random surface: the annealed case

    E-print Network

    A. A. Polotsky

    2015-06-12

    Adsorption of a symmetric (AB) random copolymer (RC) onto a symmetric (ab) random heterogeneous surface (RS) is studied in the annealed approximation by using a two-dimensional partially directed walk model of the polymer. We show that in the symmetric case, the expected a posteriori compositions of the RC and the RS have correct values (corresponding to their a priori probabilities) and do not change with the temperature, whereas second moments of monomers and sites distributions in the RC and RS change. This indicates that monomers and sites do not interconvert but only rearrange in order to provide better matching between them and, as a result, a stronger adsorption of the RC on the RS. However, any violation of the system symmetry shifts equilibrium towards the major component and/or more favorable contacts and leads to interconversion of monomers and sites.

  16. Three-Dimensional Solutions for Contact Area in Laminated Composite Pinned Joints with Symmetric and Non-Symmetric Stacking Sequences

    NASA Astrophysics Data System (ADS)

    Javadi, H.; Rajabi, I.; Yavari, V.; Kadivar, M. H.

    The aim of this study is computing and evaluating the behavior of the laminated composite plate at the contact area in single lap, mechanically fastened joints. The analyses involve three dimensional finite element models performed by ABAQUS 6.4-PR11 code to evaluate the stress distribution in contact surface, separation angle, the magnitude and location of maximum radial stress. Results are determined for composite laminates with different layer configurations and attempts are made to validate the models with previous works. For cross ply and angle ply configurations only symmetric stacking sequences are used while for quasi-isotropic laminate both symmetric and non-symmetric models are generated. In cross-ply laminate symmetric separation about bearing plane could be found while in quasi-isotropic and angle-ply laminates non-symmetric separation occurs. Also, the separation angle is less than 90° in symmetric laminates and greater than 90° in some plies of non-symmetric laminates.

  17. Symmetrical and anti-symmetrical coherent perfect absorption for acoustic waves

    SciTech Connect

    Wei, Pengjiang; Croënne, Charles; Tak Chu, Sai [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Li, Jensen, E-mail: j.li@bham.ac.uk [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom)

    2014-03-24

    We investigate tunable acoustic absorption enabled by the coherent control of input waves. It relies on coherent perfect absorption originally proposed in optics. By designing appropriate acoustic metamaterial structures with resonating effective bulk modulus or density, we show that complete absorption of incident waves impinging on the metamaterial can be achieved for either symmetrical or anti-symmetrical inputs in the forward and backward directions. By adjusting the relative phase between the two incident beams, absorption can be tuned effectively from unity to zero, making coherent control useful in applications like acoustic modulators, noise controllers, transducers, and switches.

  18. Electrochromic graphene molecules.

    PubMed

    Ji, Zhiqiang; Doorn, Stephen K; Sykora, Milan

    2015-04-28

    Polyclic aromatic hydrocarbons also called Graphene Molecules (GMs), with chemical composition C132H36(COOH)2 were synthesized in situ on the surface of transparent nanocrystalline indium tin oxide (nc-ITO) electrodes and their electronic structure was studied electrochemically and spectro-electrochemically. Variations in the potential applied onto the nc-ITO/GM electrodes induce only small changes in the observed current, but they produce dramatic changes in the absorption of the GMs, which are associated with their oxidation and reduction. Analysis of the absorption changes using a modified Nernst equation is used to determine standard potentials associated with the individual charge transfer processes. For the GMs prepared here, these were found to be E1,ox(0) = 0.77 ± 0.01 V and E2,ox(0) = 1.24 ± 0.02 V vs NHE for the first and second oxidation and E1,red(0) = -1.50 ± 0.04 V for the first reduction. The charge transfer processes are found to be nonideal. The nonideality factors associated with the oxidation and reduction processes are attributed to strong interactions between the GM redox centers. Under the conditions of potential cycling, GMs show rapid (seconds) color change with high contrast and stability. An electrochromic application is demonstrated wherein the GMs are used as the optically active component. PMID:25768313

  19. Thread bonds in molecules

    E-print Network

    Ivlev, B

    2015-01-01

    Unusual chemical bonds are proposed. Each bond is almost covalent but is characterized by the thread of a small radius $\\sim 0.6\\times 10^{-11}$cm, between two nuclei in a molecule. The main electron density is concentrated outside the thread as in a covalent bond. The thread is formed by the electron wave function which has a tendency to be singular on it. The singularity along the thread is cut off by electron "vibrations" due to the interaction with zero point electromagnetic oscillations. The electron energy has its typical value of (1-10)eV. Due to the small tread radius the uncertainty of the electron momentum inside the thread is large resulting in a large electron kinetic energy $\\sim 1 MeV$. This energy is compensated by formation of a potential well due to the reduction of the energy of electromagnetic zero point oscillations. This is similar to formation of a negative van der Waals potential. Thread bonds are stable and cannot be created or destructed in chemical or optical processes.

  20. Single molecule tracking

    DOEpatents

    Shera, E. Brooks (Los Alamos, NM)

    1988-01-01

    A detection system is provided for identifying individual particles or molecules having characteristic emission in a flow train of the particles in a flow cell. A position sensitive sensor is located adjacent the flow cell in a position effective to detect the emissions from the particles within the flow cell and to assign spatial and temporal coordinates for the detected emissions. A computer is then enabled to predict spatial and temporal coordinates for the particle in the flow train as a function of a first detected emission. Comparison hardware or software then compares subsequent detected spatial and temporal coordinates with the predicted spatial and temporal coordinates to determine whether subsequently detected emissions originate from a particle in the train of particles. In one embodiment, the particles include fluorescent dyes which are excited to fluoresce a spectrum characteristic of the particular particle. Photones are emitted adjacent at least one microchannel plate sensor to enable spatial and temporal coordinates to be assigned. The effect of comparing detected coordinates with predicted coordinates is to define a moving sample volume which effectively precludes the effects of background emissions.

  1. Metastability in molecules

    NASA Astrophysics Data System (ADS)

    Bartlett, Rodney J.

    1993-03-01

    Pentazole (HN5) has the fingerprints of a metastable molecule since even though it offers a perfectly logical, even aromatic electronic structure, it is unknown experimentally. We subjected HN5 to theoretical analysis. At the correlated level we find that for the reaction, 2HN5 - 5N2 + H2, Delta(E) is -129.1 kcal/mol resulting in an I(sub sp) of 346 as a monopropellant. Considering that derivatives of the basic structure should be made to stabilize the pentazole ring, we can consider some which will be quite energetic (examples include nitropentazole, and a bipentazole analogous to biphenyl and possibly a dinitramine pentazole (O2N)N-N5, and numerous metal, MN5 structures, where M could be Li). The prospect for actually making and using pentazoles is promising. Several recent methodology developments have been accomplished in this project. These methods, mostly unique to our effort, make it possible to perform high-level, accurate correlated calculations on much larger potential metastable species than was previously possible. These include the following: (1) Direct product decomposition approach to the full use of Abelian symmetry in coupled-cluster and MBPT applications; (2) Restricted open-shell Hartree Fock (ROHF) based CC and MBPT methods; and (3) Analytical first derivatives (i.e. gradient) for open-shell CC/MBPT methods.

  2. Single molecule tracking

    DOEpatents

    Shera, E.B.

    1987-10-07

    A detection system is provided for identifying individual particles or molecules having characteristic emission in a flow train of the particles in a flow cell. A position sensitive sensor is located adjacent the flow cell in a position effective to detect the emissions from the particles within the flow cell and to assign spatial and temporal coordinates for the detected emissions. A computer is then enabled to predict spatial and temporal coordinates for the particle in the flow train as a function of a first detected emission. Comparison hardware or software then compares subsequent detected spatial and temporal coordinates with the predicted spatial and temporal coordinates to determine whether subsequently detected emissions originate from a particle in the train of particles. In one embodiment, the particles include fluorescent dyes which are excited to fluoresce a spectrum characteristic of the particular particle. Photons are emitted adjacent at least one microchannel plate sensor to enable spatial and temporal coordinates to be assigned. The effect of comparing detected coordinates with predicted coordinates is to define a moving sample volume which effectively precludes the effects of background emissions. 3 figs.

  3. Top 10 Nano & Chem Eng TMVogel, updated Fall 2012 Top 10 Things UCSD Nanoengineering &

    E-print Network

    Hampton, Randy

    Top 10 Nano & Chem Eng TMVogel, updated Fall 2012 Top 10 Things UCSD Nanoengineering & Chemical Engineering Researchers Need to Know http://libguides.ucsd.edu/nano http://libguides.ucsd.edu/chemeng http

  4. Symmetric Euler orientation representations for orientational averaging.

    PubMed

    Mayerhöfer, Thomas G

    2005-09-01

    A new kind of orientation representation called symmetric Euler orientation representation (SEOR) is presented. It is based on a combination of the conventional Euler orientation representations (Euler angles) and Hamilton's quaternions. The properties of the SEORs concerning orientational averaging are explored and compared to those of averaging schemes that are based on conventional Euler orientation representations. To that aim, the reflectance of a hypothetical polycrystalline material with orthorhombic crystal symmetry was calculated. The calculation was carried out according to the average refractive index theory (ARIT [T.G. Mayerhöfer, Appl. Spectrosc. 56 (2002) 1194]). It is shown that the use of averaging schemes based on conventional Euler orientation representations leads to a dependence of the result from the specific Euler orientation representation that was utilized and from the initial position of the crystal. The latter problem can be overcome partly by the introduction of a weighing factor, but only for two-axes-type Euler orientation representations. In case of a numerical evaluation of the average, a residual difference remains also if a two-axes type Euler orientation representation is used despite of the utilization of a weighing factor. In contrast, this problem does not occur if a symmetric Euler orientation representation is used as a matter of principle, while the result of the averaging for both types of orientation representations converges with increasing number of orientations considered in the numerical evaluation. Additionally, the use of a weighing factor and/or non-equally spaced steps in the numerical evaluation of the average is not necessary. The symmetrical Euler orientation representations are therefore ideally suited for the use in orientational averaging procedures. PMID:16043055

  5. Symmetrical band-pass loudspeaker systems

    NASA Astrophysics Data System (ADS)

    Matusiak, Grzegorz Piotr

    2001-12-01

    Loudspeaker systems are analyzed in a doctoral dissertation. The dissertation concerns loudspeaker systems, which are known as subwoofers or band-pass loudspeaker systems. Their advantages include: high- quality sound reproduction in the low-frequency range, small dimensions, small nonlinear distortions and the fact that they can be placed anywhere in a room or car. Band-pass loudspeaker systems are used widely in the so- called Home Theatre as well as to provide sound in cinema, theatre, concert, discotheque, opera, operetta, philharmonic and amphitheater halls, at open-air concerts, and so on. Various designs are mass-produced by a large number of manufacturers. The study covers an analysis of band-pass loudspeaker systems to which the frequency transformation, i.e. the reactance transformation, has been applied. Since this is a symmetrical transformation, amplitude frequency responses of the studied band-pass systems are also symmetrical (logarithmic scale of a frequency). As a result, the high-pass loudspeaker system design method, known as the Thiele-Small, Benson analysis, can be employed. The investigations include the formulation of band-pass system equations (fourth, sixth and eighth-order polynomials) and the subsequent derivation of relations for the calculation of system parameters. The obtained results enable the calculation of optimum designs for prescribed alignments, e.g. (Chebyshev) equal-ripple, (Butterworth) maximally flat, or quasi-maximally flat (QB). The analysis covers fourth, sixth and eighth-order symmetrical systems. Eighth-order systems have been divided into three kinds according to three ways of physical realization. The doctoral dissertation includes band-pass loudspeaker systems, which can be designed with active or passive filters or without the filter. Designed systems consist of a loudspeaker whose front of a diaphragm is loaded with a Helmholtz resonator, i.e. an enclosure with a vent, which radiates sound outwards. The back is loaded with a closed-box or the Helmholtz resonator.

  6. Featured Molecules: Sucrose and Vanillin

    NASA Astrophysics Data System (ADS)

    Coleman, William F.; Wildman, Randall J.

    2003-04-01

    The WebWare molecules of the month for April relate to the sense of taste. Apple Fool, the JCE Classroom Activity, mentions sucrose and vanillin and their use as flavorings. Fully manipulable (Chime) versions of these and other molecules are available at Only@JCE Online.

  7. Intermolecular Forces for Polyatomic Molecules

    Microsoft Academic Search

    Taro Kihara

    1967-01-01

    Part I is a review of papers dealing with the convex-core potential (sometimes called the Kihara potential) of intermolecular forces, which is a useful mathematical model for the interaction between polyatomic molecules in gases. For molecular crystals electric multipoles of the molecules often play a decisive role in the crystal structures. This fact is demonstrated in Part II by use

  8. Micro-Kelvin cold molecules.

    SciTech Connect

    Strecker, Kevin E.; Chandler, David W.

    2009-10-01

    We have developed a novel experimental technique for direct production of cold molecules using a combination of techniques from atomic optical and molecular physics and physical chemistry. The ability to produce samples of cold molecules has application in a broad spectrum of technical fields high-resolution spectroscopy, remote sensing, quantum computing, materials simulation, and understanding fundamental chemical dynamics. Researchers around the world are currently exploring many techniques for producing samples of cold molecules, but to-date these attempts have offered only limited success achieving milli-Kelvin temperatures with low densities. This Laboratory Directed Research and Development project is to develops a new experimental technique for producing micro-Kelvin temperature molecules via collisions with laser cooled samples of trapped atoms. The technique relies on near mass degenerate collisions between the molecule of interest and a laser cooled (micro-Kelvin) atom. A subset of collisions will transfer all (nearly all) of the kinetic energy from the 'hot' molecule, cooling the molecule at the expense of heating the atom. Further collisions with the remaining laser cooled atoms will thermally equilibrate the molecules to the micro-Kelvin temperature of the laser-cooled atoms.

  9. Intermolecular forces between large molecules

    Microsoft Academic Search

    A. T. Amos; R. J. Crispin

    1976-01-01

    The long-range interaction between large molecules with localized electrons is written as the sum of individual interactions between localized charge distributions. Using minimal basis set ab initio Hartree-Fock wavefunctions the parameters needed to compute these interactions are obtained for water, methane and ethane. Interactions between pairs of these molecules are computed for various orientations to demonstrate the complex orientational dependence

  10. Loosely-Bound Diatomic Molecules.

    ERIC Educational Resources Information Center

    Balfour, W. J.

    1979-01-01

    Discusses concept of covalent bonding as related to homonuclear diatomic molecules. Article draws attention to the existence of bound rare gas and alkaline earth diatomic molecules. Summarizes their molecular parameters and offers spectroscopic data. Strength and variation with distance of interatomic attractive forces is given. (Author/SA)

  11. Retarded Dispersion Forces Between Molecules

    Microsoft Academic Search

    A. D. McLachlan

    1963-01-01

    The frequency-dependent susceptibility of the molecules and of the electromagnetic field is used to calculate the force between two molecules at zero temperature. The field susceptibility at imaginary frequency, which is the Laplace transform of the retarded potentials, is found from the commutation relations, otherwise we do not need quantum field theory. A method of `images' gives the force between

  12. Theory of molecule metal nano-particle interaction: Quantum description of plasmonic lasing

    NASA Astrophysics Data System (ADS)

    Zhang, Yuan; May, Volkhard

    2015-06-01

    The recent quantum description of a few molecules interacting with plasmon excitations of a spherical metal nano-particle (MNP) as presented in the work of Zhang and May [Phys. Rev. B 89, 245441 (2014)] is extended to systems with up to 100 molecules. We demonstrate the possibility of multiple plasmon excitation and describe their conversion into far-field photons. The calculation of the steady-state photon emission spectrum results in an emission line-narrowing with an increasing number of molecules coupled to the MNP. This is considered as an essential criterion for the action of the molecule-MNP system as a nano-laser. To have exact results for systems with up to 20 molecules, we proceed as recently described by Richter et al. [Phys. Rev. B 91, 035306 (2015)] and study a highly symmetric system. It assumes an equatorial and regular position of identical molecules in such a way that their coupling is dominated by that to a single MNP dipole-plasmon excitation. Changing from the exact computation of the system's complete density matrix to an approximate theory based on the reduced plasmon density matrix, systems with more than 100 molecules can be described. Finally, nonlinear rate equations are proposed which reproduce the mean number of excited plasmons in their dependence of the number of molecules and of the used pump rate. The second order intensity correlation function of emitted photons is related to the respective plasmon correlation function which approaches unity when the system starts lasing.

  13. Theory of molecule metal nano-particle interaction: Quantum description of plasmonic lasing.

    PubMed

    Zhang, Yuan; May, Volkhard

    2015-06-14

    The recent quantum description of a few molecules interacting with plasmon excitations of a spherical metal nano-particle (MNP) as presented in the work of Zhang and May [Phys. Rev. B 89, 245441 (2014)] is extended to systems with up to 100 molecules. We demonstrate the possibility of multiple plasmon excitation and describe their conversion into far-field photons. The calculation of the steady-state photon emission spectrum results in an emission line-narrowing with an increasing number of molecules coupled to the MNP. This is considered as an essential criterion for the action of the molecule-MNP system as a nano-laser. To have exact results for systems with up to 20 molecules, we proceed as recently described by Richter et al. [Phys. Rev. B 91, 035306 (2015)] and study a highly symmetric system. It assumes an equatorial and regular position of identical molecules in such a way that their coupling is dominated by that to a single MNP dipole-plasmon excitation. Changing from the exact computation of the system's complete density matrix to an approximate theory based on the reduced plasmon density matrix, systems with more than 100 molecules can be described. Finally, nonlinear rate equations are proposed which reproduce the mean number of excited plasmons in their dependence of the number of molecules and of the used pump rate. The second order intensity correlation function of emitted photons is related to the respective plasmon correlation function which approaches unity when the system starts lasing. PMID:26071722

  14. Expanding symmetric multiprocessor capability through gang scheduling

    SciTech Connect

    Jette, M.A.

    1998-03-01

    Symmetric Multiprocessor (SMP) systems normally provide both space- sharing and time-sharing to insure high system utilization and good responsiveness. However the prevailing lack of concurrent scheduling for parallel programs precludes SMP use in addressing many large-scale problems. Tightly synchronized communications are impractical and normal time-sharing reduces the benefit of cache memory. Evidence gathered at Lawrence Livermore National Laboratory (LLNL) indicates that gang scheduling can increase the capability of SMP systems and parallel program performance without adverse impact upon system utilization or responsiveness.

  15. Gapped symmetric boundaries of topological insulators

    NASA Astrophysics Data System (ADS)

    Lee, Dung-Hai; Lu, Yuan-Ming

    2014-03-01

    Topological insulators (TIs) are gapped quantum phases which host symmetry-protected gapless boundary excitations. On the other hand, the boundary states can be gapped by spontaneously breaking symmetry. We show that topological defects on the symmetry-broken boundary cannot proliferate due to their fractional statistics. A gapped symmetric boundary, however, can be achieved between a TI phase and certain fractionalized phase by condensing the bound state of a topological defect and an anyon. Such a hybrid structure containing TI and fractionalized phase generally support ground state degeneracy on torus.

  16. Single mode PT symmetric large area lasers

    NASA Astrophysics Data System (ADS)

    Hodaei, Hossein; Miri, Mohammad-Ali; Heinrich, Matthias; Christodoulides, Demetrios N.; Khajavikhan, Mercedeh

    2014-09-01

    We experimentally demonstrate single longitudinal mode operation in microring laser using the concept of PT symmetry. A PT-symmetric coupled resonator arrangement can considerably enhance the maximum achievable gain of single mode microring cavity. The method is broadband thus work well for inhomogenously broadened gain mediums. It doesn't rely on any additional component to ensure its mode selective performance, and it is robust with respect to fabrication inaccuracies. This result may pave the way for a novel way of designing integrated laser sources based on PT symmetry.

  17. Stability of Reflection Symmetric Collapsing Structures

    E-print Network

    M. Sharif; M. Zaeem Ul Haq Bhatti

    2015-05-25

    In this paper, we explore instability regions of non-static axial reflection symmetric spacetime with anisotropic source in the interior. We impose linear perturbation on the Einstein field equations and dynamical equations to establish the collapse equation. The effects of different physical factors like energy density and anisotropic stresses on the instability regions are studied under Newtonian and post-Newtonian limits. We conclude that stiffness parameter has a significant role in this analysis while the reflection terms increase instability ranges of non-static axial collapse.

  18. Stability of Reflection Symmetric Collapsing Structures

    E-print Network

    Sharif, M

    2015-01-01

    In this paper, we explore instability regions of non-static axial reflection symmetric spacetime with anisotropic source in the interior. We impose linear perturbation on the Einstein field equations and dynamical equations to establish the collapse equation. The effects of different physical factors like energy density and anisotropic stresses on the instability regions are studied under Newtonian and post-Newtonian limits. We conclude that stiffness parameter has a significant role in this analysis while the reflection terms increase instability ranges of non-static axial collapse.

  19. Note on free symmetric rigid body motion

    NASA Astrophysics Data System (ADS)

    Dragovi?, Vladimir; Gaji?, Borislav; Jovanovi?, Božidar

    2015-05-01

    We consider the Euler equations of motion of a free symmetric rigid body around a fixed point, restricted to the invariant subspace given by the zero values of the corresponding linear Noether integrals. In the case of the SO( n - 2)-symmetry, we show that almost all trajectories are periodic and that the motion can be expressed in terms of elliptic functions. In the case of the SO( n - 3)-symmetry, we prove the solvability of the problem by using a recent Kozlov's result on the Euler-Jacobi-Lie theorem.

  20. Quantum asymmetric cryptography with symmetric keys

    E-print Network

    Fei Gao; Qiao-Yan Wen; Su-Juan Qin; Fu-Chen Zhu

    2008-10-16

    Based on quantum encryption, we present a new idea for quantum public-key cryptography (QPKC) and construct a whole theoretical framework of a QPKC system. We show that the quantum-mechanical nature renders it feasible and reasonable to use symmetric keys in such a scheme, which is quite different from that in conventional public-key cryptography. The security of our scheme is analyzed and some features are discussed. Furthermore, the state-estimation attack to a prior QPKC scheme is demonstrated.

  1. Communities and classes in symmetric fractals

    NASA Astrophysics Data System (ADS)

    Krawczyk, Ma?gorzata J.

    2015-07-01

    Two aspects of fractal networks are considered: the community structure and the class structure, where classes of nodes appear as a consequence of a local symmetry of nodes. The analyzed systems are the networks constructed for two selected symmetric fractals: the Sierpinski triangle and the Koch curve. Communities are searched for by means of a set of differential equations. Overlapping nodes which belong to two different communities are identified by adding some noise to the initial connectivity matrix. Then, a node can be characterized by a spectrum of probabilities of belonging to different communities. Our main goal is that the overlapping nodes with the same spectra belong to the same class.

  2. Carbon nanotube diode fabricated by contact engineering with self-assembled molecules

    NASA Astrophysics Data System (ADS)

    Kim, Byoung-Kye; Kim, Ju-Jin; So, Hye-Mi; Kong, Ki-jeong; Chang, Hyunju; Lee, Jeong-O.; Park, Noejung

    2006-12-01

    The authors report the construction of carbon nanotube Schottky diodes by covering a selectively exposed area of the electrode with self-assembling molecules. Two self-assembling molecules with different polarities, 2-aminoethanethiol and 3-mercaptopropionic acid, were used to modify the Fermi level lineup at the selected contact. The devices showed p-type behavior with symmetric I-V showing clear rectifying behavior after treatment of one contact with 2-aminoethanethiol. Their experiment, in conjunction with the results of ab initio electronic structure calculations, suggests that the diode action stems from the asymmetric Fermi level lineup between the bare and engineered contacts.

  3. Dynamics of confined water molecules

    PubMed Central

    Gilijamse, J. J.; Lock, A. J.; Bakker, H. J.

    2005-01-01

    We present femtosecond midinfrared pump–probe measurements of the molecular motion and energy-transfer dynamics of a water molecule that is enclosed by acetone molecules. These confined water molecules show hydrogen-bond and orientational dynamics that are much slower than in bulk liquid water. This behavior is surprising because the hydrogen bonds to the C=O groups of the acetone molecules are weaker than the hydrogen bonds in bulk water. The energy transfer between the O—H groups of the confined water molecules has a time constant of 1.3 ± 0.2 ps, which is >20 times slower than in bulk water. We find that this energy transfer is governed completely by the rate at which hydrogen bonds are broken and reformed, and we identify the short-lived molecular complex that forms the transition state of this process. PMID:15722413

  4. Continuation in Spatial Dimension and the 1\\/D Expansion for the Hydrogen Molecule-Ion

    Microsoft Academic Search

    Mario Manuel Lopez

    1991-01-01

    In this thesis we derive expansion coefficients for the delta equiv {1over D} expansion of the hydrogen molecule-ion (HMI) ground-state energy, E(delta), in symmetric configuration; D represents cartesian spatial dimension. We have calculated the expansion coefficients to ~50^{th } order for various values of internuclear distance, R. The expansion for E(delta) is asymptotic and divergent, requiring that we find an

  5. Tools for top physics at D0

    E-print Network

    Amnon Harel

    2008-07-24

    Top quark measurements rely on the jet energy calibration and often on b-quark identification. We discuss these and other tools and how they apply to top quark analyses at D0. In particular some of the nuances that result from D0's data driven approach to these issues are presented.

  6. Thermionic topping of electric power plants

    Microsoft Academic Search

    E. J. Britt; G. O. Fitzpatrick; N. S. Rasor

    1975-01-01

    The most likely use of thermionic conversion is in the form of a topping cycle combined with a steam-turbogenerator plant. A specific reference system is chosen in which the thermionic topping cycle occurs in thermionic heat exchangers referred to as large, modular thermionic units to which heat is transferred from a separate heat source and which reject their heat to

  7. Your Hit Parade: The Top Ten Most

    E-print Network

    Berndt, Bruce C.

    Your Hit Parade: The Top Ten Most Fascinating Formulas in Ramanujan's Lost Notebook George E of mathematics at Penn- sylvania State University, University Park. His email ad- dress is andrews Ten Most Fascinating Formulas from Ra- manujan's Lost Notebook. The choices for the Top Ten Formulas

  8. Technology Review: WBT Systems' TopClass.

    ERIC Educational Resources Information Center

    Szabo, Sharon

    1998-01-01

    Discusses TopClass, a Web-based tool and delivery system used for online courses, and its use at Schoolcraft College in Michigan. TopClass offers many benefits, including a self-contained management system, secured access, user-friendly instructions for coursework area creation, e-mail, bulletin boards, a secured testing mechanism and student…

  9. Supercharged topping rocket propellant feed system

    NASA Technical Reports Server (NTRS)

    Stewart, W. L.; Ginsburg, A.; Hartmann, M. J. (inventors)

    1979-01-01

    A rocket propellant feed system utilizing a bleed turbopump to supercharge a topping turbopump is presented. The bleed turbopump is of a low pressure type to meet the cavitation requirements imposed by the propellant storage tanks. The topping turbopump is of a high pressure type and develops 60 to 70 percent of the pressure rise in the propellant.

  10. Top Managerial Prestige and Organizational Bankruptcy.

    ERIC Educational Resources Information Center

    D'Aveni, Richard

    1990-01-01

    Suggests that bankruptcy occurs when creditors withdraw their support from a firm's top management team. Five characteristics measuring the relative status of top teams tested on a sample of 57 large bankrupt firms and 57 matched firms revealed that membership in political elites and board connections were negatively associated with bankruptcy.…

  11. The Sakai Spinner: A Paperclip Top

    ERIC Educational Resources Information Center

    Corrao, Christian T.

    2014-01-01

    A challenge: Can you create a stable top from a single paper clip? Several interesting solutions to this problem were provided by Takao Sakai from Japan, the requirement of each being that the center of gravity be located on the vertical y-axis at the center of the top. In the simplest configuration, we see that there exists a single angle ?…

  12. CP violation in top-quark physics

    E-print Network

    German Valencia

    2010-07-27

    In this talk I review how to search for CP violation in top-quark pair production and decay using T-odd correlations. I discuss two examples which illustrate many of the relevant features: CP violation in a heavy neutral Higgs boson; and CP violating anomalous top-quark couplings. I present some numerical results for the LHC and some for the Tevatron.

  13. Single top production at the LHC

    E-print Network

    Escobar, Carlos; The ATLAS collaboration

    2015-01-01

    A review of the recent results on measurements of cross-sections and top quark properties in single top quark processes, performed at the LHC by ATLAS and CMS is presented. The measurements are in good agreement with predictions and no deviations from Standard Model expectations have been seen so far.

  14. Tools for top physics at D0

    SciTech Connect

    Harel, Amnon

    2008-07-01

    Top quark measurements rely on the jet energy calibration and often on b-quark identification. We discuss these and other tools and how they apply to top quark analyses at D0. In particular some of the nuances that result from D0's data driven approach to these issues are presented.

  15. Top scoring pair classifiers: asymptotics and applications

    E-print Network

    Paris-Sud XI, Université de

    Top scoring pair classifiers: asymptotics and applications Christophe Denis Laboratoire MAP5, UMR.denis@parisdescartes.fr Abstract The original top scoring pair (TSP) classifier was proposed by Geman et al. (2004) for binary classifier and their two cross-validated counterparts relative to two different risks: the classical

  16. Measurement of the Top Quark Mass

    Microsoft Academic Search

    Steven R. Blusk; for the CDF; M. G. Albrow; A. Amadon; S. R. Amendolia; D. Amidei; J. Antos; S. Aota; G. Apollinari; T. Arisawa; T. Asakawa; W. Ashmanskas; M. Atac; P. Azzi-Bacchetta; N. Bacchetta; S. Bagdasarov; M. W. Bailey; P. de Barbaro; A. Barbaro-Galtieri; V. E. Barnes; B. A. Barnett; M. Barone; G. Bauer; T. Baumann; F. Bedeschi; S. Behrends; S. Belforte; G. Bellettini; J. Bellinger; D. Benjamin; J. Bensinger; A. Beretvas; J. P. Berge; J. Berryhill; S. Bertolucci; S. Bettelli; B. Bevensee; A. Bhatti; K. Biery; C. Bigongiari; M. Binkley; D. Bisello; R. E. Blair; C. Blocker; A. Bodek; W. Bokhari; G. Bolla; Y. Bonushkin; D. Bortoletto; J. Boudreau; L. Breccia; C. Bromberg; N. Bruner; R. Brunetti; E. Buckley-Geer; H. S. Budd; K. Burkett; G. Busetto; A. Byon-Wagner; K. L. Byrum; M. Campbell; A. Caner; W. Carithers; D. Carlsmith; J. Cassada; A. Castro; D. Cauz; A. Cerri; P. S. Chang; H. Y. Chao; J. Chapman; M.-T. Cheng; M. Chertok; G. Chiarelli; C. N. Chiou; F. Chlebana; L. Christofek; M. L. Chu; S. Cihangir; A. G. Clark; M. Cobal; E. Cocca; M. Contreras; J. Conway; J. Cooper; M. Cordelli; D. Costanzo; C. Couyoumtzelis; D. Cronin-Hennessy; R. Culbertson; D. Dagenhart; T. Daniels; F. Dejongh; S. dell'Agnello; M. dell'Orso; R. Demina; L. Demortier; M. Deninno; P. F. Derwent; T. Devlin; J. R. Dittmann; S. Donati; J. Done; T. Dorigo; N. Eddy; K. Einsweiler; J. E. Elias; R. Ely; E. Engels; W. Erdmann; D. Errede; S. Errede; Q. Fan; R. G. Feild; Z. Feng; C. Ferretti; I. Fiori; B. Flaugher; G. W. Foster; M. Franklin; J. Freeman; J. Friedman; H. Frisch; Y. Fukui; S. Gadomski; S. Galeotti; M. Gallinaro; O. Ganel; M. Garcia-Sciveres; A. F. Garfinkel; C. Gay; S. Geer; D. W. Gerdes; P. Giannetti; N. Giokaris; P. Giromini; G. Giusti; M. Gold; A. Gordon; A. T. Goshaw; Y. Gotra; K. Goulianos; H. Grassmann; L. Groer; C. Grosso-Pilcher; G. Guillian; J. Guimaraes da Costa; R. S. Guo; C. Haber; E. Hafen; S. R. Hahn; T. Handa; R. Handler; F. Happacher; K. Hara; A. D. Hardman; R. M. Harris; F. Hartmann; J. Hauser; E. Hayashi; J. Heinrich; W. Hao; B. Hinrichsen; K. D. Hoffman; M. Hohlmann; C. Holck; R. Hollebeek; L. Holloway; Z. Huang; B. T. Huffman; R. Hughes; J. Huston; J. Huth; H. Ikeda; M. Incagli; J. Incandela; G. Introzzi; J. Iwai; Y. Iwata; E. James; H. Jensen; U. Joshi; E. Kajfasz; H. Kambara; T. Kamon; T. Kaneko; K. Karr; H. Kasha; Y. Kato; T. A. Keaffaber; K. Kelley; R. D. Kennedy; R. Kephart; D. Kestenbaum; D. Khazins; T. Kikuchi; B. J. Kim; H. S. Kim; S. H. Kim; Y. K. Kim; L. Kirsch; S. Klimenko; D. Knoblauch; P. Koehn; A. Köngeter; K. Kondo; J. Konigsberg; K. Kordas; A. Korytov; E. Kovacs; W. Kowald; J. Kroll; M. Kruse; S. E. Kuhlmann; E. Kuns; K. Kurino; T. Kuwabara; A. T. Laasanen; S. Lami; S. Lammel; J. I. Lamoureux; M. Lancaster; M. Lanzoni; G. Latino; T. Lecompte; S. Leone; J. D. Lewis; P. Limon; M. Lindgren; T. M. Liss; J. B. Liu; Y. C. Liu; N. Lockyer; O. Long; C. Loomis; M. Loreti; D. Lucchesi; P. Lukens; S. Lusin; J. Lys; K. Maeshima; P. Maksimovic; M. Mangano; M. Mariotti; J. P. Marriner; A. Martin; J. A. Matthews; P. Mazzanti; P. McIntyre; P. Melese; M. Menguzzato; A. Menzione; E. Meschi; S. Metzler; C. Miao; T. Miao; G. Michail; R. Miller; H. Minato; S. Miscetti; M. Mishina; S. Miyashita; N. Moggi; E. Moore; Y. Morita; A. Mukherjee; T. Muller; P. Murat; S. Murgia; H. Nakada; I. Nakano; C. Nelson; D. Neuberger; C. Newman-Holmes; C.-Y. P. Ngan; L. Nodulman; A. Nomerotski; S. H. Oh; T. Ohmoto; T. Ohsugi; R. Oishi; M. Okabe; T. Okusawa; J. Olsen; C. Pagliarone; R. Paoletti; V. Papadimitriou; S. P. Pappas; N. Parashar; A. Parri; J. Patrick; G. Pauletta; M. Paulini; A. Perazzo; L. Pescara; M. D. Peters; T. J. Phillips; G. Piacentino; M. Pillai; K. T. Pitts; R. Plunkett; L. Pondrom; J. Proudfoot; F. Ptohos; G. Punzi; K. Ragan; D. Reher; M. Reischl; A. Ribon; F. Rimondi; L. Ristori; W. J. Robertson; T. Rodrigo; S. Rolli; L. Rosenson; R. Roser; T. Saab; W. K. Sakumoto; D. Saltzberg; A. Sansoni; L. Santi; H. Sato; P. Schlabach; E. E. Schmidt; M. P. Schmidt; A. Scott; A. Scribano; S. Segler; S. Seidel; Y. Seiya; F. Semeria; T. Shah; M. D. Shapiro; N. M. Shaw; P. F. Shepard; T. Shibayama; M. Shimojima; M. Shochet; J. Siegrist; A. Sill; P. Sinervo; P. Singh; K. Sliwa; C. Smith; F. D. Snider; J. Spalding; T. Speer; P. Sphicas; F. Spinella; M. Spiropulu; L. Spiegel; L. Stanco; J. Steele; A. Stefanini; R. Ströhmer; J. Strologas; F. Strumia; D. Stuart; K. Sumorok; J. Suzuki; T. Suzuki; T. Takahashi; T. Takano; R. Takashima; K. Takikawa; M. Tanaka; B. Tannenbaum; F. Tartarelli; W. Taylor; M. Tecchio; P. K. Teng; Y. Teramoto; K. Terashi; S. Tether; D. Theriot; T. L. Thomas; R. Thurman-Keup; M. Timko; P. Tipton; A. Titov; S. Tkaczyk; D. Toback; K. Tollefson; A. Tollestrup; H. Toyoda; W. Trischuk; J. F. de Troconiz; S. Truitt; J. Tseng; N. Turini; T. Uchida; F. Ukegawa; J. Valls; S. C. van den Brink; S. Vejcik

    1998-01-01

    We present a measurement of the top quark mass using a sample of tt¯ decays into an electron or a muon, a neutrino, and four jets. The data were collected in pp¯ collisions at s = 1.8 TeV with the Collider Detector at Fermilab and correspond to an integrated luminosity of 109 pb-1. We measure the top quark mass to

  17. Search for top quark at Fermilab Collider

    SciTech Connect

    Sliwa, K. [Tufts Univ., Medford, MA (United States). Dept. of Physics; The CDF Collaboration

    1991-10-01

    The status of a search for the top quark with Collider Detector at Fermilab (CDF), based on a data sample recorded during the 1988--1989 run is presented. The plans for the next Fermilab Collider run in 1992--1993 and the prospects of discovering the top quark are discussed. 19 refs., 4 figs., 2 tabs.

  18. Pinch Experiments in a Table Top Generator

    NASA Astrophysics Data System (ADS)

    Pavez, Cristian; Tarifeño, Ariel; Moreno, José; Soto, Leopoldo

    2009-01-01

    The design and construction of a table top multipurpose capacitor bank of hundred of Joules and hundred of kiloAmperes conceived to be used in small scale Z-pinch experiments is reported. A recent result on a Z-pinch gas embedded discharge using hollow conical electrodes done in a similar table top generator is also presented.

  19. The method of loop molecules and the topology of the Kovalevskaya top

    NASA Astrophysics Data System (ADS)

    Bolsinov, A. V.; Richter, P. H.; Fomenko, A. T.

    2000-02-01

    A method for calculating topological invariants of the foliation of a phase space into invariant Liouville tori in the case of integrable Hamiltonian systems with two degrees of freedom is put forward. The structure of this foliation is completely described for the Kovalevskaya integrable case in rigid body dynamics.

  20. Thermionic topping of electric power plants

    NASA Technical Reports Server (NTRS)

    Britt, E. J.; Fitzpatrick, G. O.; Rasor, N. S.

    1975-01-01

    The most likely use of thermionic conversion is in the form of a topping cycle combined with a steam-turbogenerator plant. A specific reference system is chosen in which the thermionic topping cycle occurs in thermionic heat exchangers referred to as large, modular thermionic units to which heat is transferred from a separate heat source and which reject their heat to a conventional steam turboelectric system. Results of analysis show that the performance and cost criteria for practical thermionic topping of large electric power plants are well within the reach of demonstrated and foreseeable converter capabilities. Thermionic topping has many significant advantages over unconventional cycles proposed for topping applications, including level of demonstrated and projected performance and lifetime, development time, and design simplicity.

  1. Single top quark production at the Tevatron

    E-print Network

    CDF; D0 collaborations; Aran Garcia-Bellido for the collaboration

    2010-08-01

    The observation of single top quark production by the CDF and D0 collaborations is one of the flagship measurements of the Run II of the Tevatron. The Tevatron combined single top quark cross section is measured to be: $\\sigma(tb+X,~tqb+X)=2.8^{+0.6}_{-0.5}$~pb for a top quark mass of 170~GeV. This result is in agreement with the standard model production of a single top quark together with a jet in $\\ppbar$ collisions at $\\sqrt{s}$=1.96~TeV and allows to measure the CKM matrix element $|V_{tb}|$ without assumptions about the number of quark families. Other analyses involving tau leptons have been performed, and several properties, like the top quark width or the polarization have been measured.

  2. TOP500 Supercomputers for June 2002

    SciTech Connect

    Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack; Simon, Horst D.

    2002-06-20

    19th Edition of TOP500 List of World's Fastest Supercomputers Released MANNHEIM, Germany; KNOXVILLE, Tenn.;&BERKELEY, Calif. In what has become a much-anticipated event in the world of high-performance computing, the 19th edition of the TOP500 list of the worlds fastest supercomputers was released today (June 20, 2002). The recently installed Earth Simulator supercomputer at the Earth Simulator Center in Yokohama, Japan, is as expected the clear new number 1. Its performance of 35.86 Tflop/s (trillions of calculations per second) running the Linpack benchmark is almost five times higher than the performance of the now No.2 IBM ASCI White system at Lawrence Livermore National Laboratory (7.2 Tflop/s). This powerful leap frogging to the top by a system so much faster than the previous top system is unparalleled in the history of the TOP500.

  3. Top-of-Rail lubricant

    SciTech Connect

    Alzoubi, M. F.; Fenske, G. R.; Erck, R. A.; Boparai, A. S.

    2000-07-14

    Analysis of the volatile and semivolatile fractions collected after use of the TOR lubricant indicated that other than contaminants in the collection laboratory, no compounds on the EPA's Target Compound Lists (Tables 2 and 5) were detected in these fractions. The data of these qualitative analyses, given in the various tables in the text, indicate only the relative amounts of the tentatively identified compounds. The authors recommend that quantitative analysis be performed on the volatile and semivolatile fractions to allow confirmation of the tentatively identified compounds and to obtain absolute amounts of the detected compounds. Additionally, the semivolatile fraction should be analyzed by liquid chromatography/mass spectrometry to identify compounds that are not chromatographable under the temperature program used for determination of semivolatile compounds. Introducing the top-of-rail (TOR) lubricant into the wheel/rail interface results in a reduction of almost 60% of lateral friction force over the forces encountered under dry conditions. This reveals good potential for energy savings, as well as wear reduction, for railroad companies. In TOR lubrication, an increase in the angle of attack and axle load results in increased lateral friction and rate of lubricant consumption. The most efficient TOR lubricant quantity to be used in the wheel/rail interface must be calculated precisely according to the number of cars, axle loads, train speed, and angle of attack.

  4. Electroweak Baryogenesis in R-symmetric Supersymmetry

    SciTech Connect

    Fok, R.; Kribs, Graham D.; Martin, Adam; Tsai, Yuhsin

    2013-03-01

    We demonstrate that electroweak baryogenesis can occur in a supersymmetric model with an exact R-symmetry. The minimal R-symmetric supersymmetric model contains chiral superfields in the adjoint representation, giving Dirac gaugino masses, and an additional set of "R-partner" Higgs superfields, giving R-symmetric \\mu-terms. New superpotential couplings between the adjoints and the Higgs fields can simultaneously increase the strength of the electroweak phase transition and provide additional tree-level contributions to the lightest Higgs mass. Notably, no light stop is present in this framework, and in fact, we require both stops to be above a few TeV to provide sufficient radiative corrections to the lightest Higgs mass to bring it up to 125 GeV. Large CP-violating phases in the gaugino/higgsino sector allow us to match the baryon asymmetry of the Universe with no constraints from electric dipole moments due to R-symmetry. We briefly discuss some of the more interesting phenomenology, particularly of the of the lightest CP-odd scalar.

  5. Fast numerical determination of symmetric sparsity patterns

    SciTech Connect

    Carter, R.G. [Univ. of Minnesota, Minneapolis (United States)

    1994-08-01

    The author considers a function g: {Re}{sup n} {yields} {Re}{sup n} for which the Jacobian is symmetric and sparse. Such functions often arise, for instance, in numerical optimization, where g is the gradient of some objective function f so that the Jacobian of g is the Hessian of f. In many such applications one can generate extremely efficient algorithms by taking advantage of the sparsity structure of the problem if this pattern is known a priori. Unfortunately, determining such sparsity structures by hand is often difficult and prone to error. If one suspects a mistake has been made, or if g is a {open_quotes}black box{close_quotes} so that the true structure is completely unknown, one often has no alternative but to compute the entire matrix by finite differences - a prohibitively expensive task for large problems. The author shows that it is possible to numerically determine symmetric sparsity patterns using a relatively small number of g evaluations. Numerical results are shown for n up to 100,000 in which all nonzeros in the Jacobian are correctly identified in about one-hundredth of the time required to estimate the sparsity structure by a full finite difference calculation. When a good initial guess for the sparsity structure is available, numerical results are presented for n up to 500,000, in which all missing nonzeros are correctly located almost five-thousand times faster than would be possible with a full finite difference calculation.

  6. Integrable deformations of strings on symmetric spaces

    NASA Astrophysics Data System (ADS)

    Hollowood, Timothy J.; Miramontes, J. Luis; Schmidtt, David M.

    2014-11-01

    A general class of deformations of integrable sigma-models with symmetric space F/G target-spaces are found. These deformations involve defining the non-abelian T dual of the sigma-model and then replacing the coupling of the Lagrange multiplier imposing flatness with a gauged F/F WZW model. The original sigma-model is obtained in the limit of large level. The resulting deformed theories are shown to preserve both integrability and the equations-of-motion, but involve a deformation of the symplectic structure. It is shown that this deformed symplectic structure involves a linear combination of the original Poisson bracket and a generalization of the Faddeev-Reshetikhin Poisson bracket which we show can be re-expressed as two decoupled F current algebras. It is then shown that the deformation can be incorporated into the classical model of strings on via a generalization of the Pohlmeyer reduction. In this case, in the limit of large sigma-model coupling it is shown that the theory becomes the relativistic symmetric space sine-Gordon theory. These results point to the existence of a deformation of this kind for the full Green-Schwarz superstring on AdS5 × S 5.

  7. Compressible flow about symmetrical Joukowski profiles

    NASA Technical Reports Server (NTRS)

    Kaplan, Carl

    1938-01-01

    The method of Poggi is employed for the determination of the effects of compressibility upon the flow past an obstacle. A general expression for the velocity increment due to compressibility is obtained. The general result holds whatever the shape of the obstacle; but, in order to obtain the complete solution, it is necessary to know a certain Fourier expansion of the square of the velocity of flow past the obstacle. An application is made to the case flow of a symmetrical Joukowski profile with a sharp trailing edge, fixed in a stream of an arbitrary angle of attack and with the circulation determined by the Kutta condition. The results are obtained in a closed form and are exact insofar as the second approximation to the compressible flow is concerned, the first approximation being the result for the corresponding incompressible flow. Formulas for lift and moment analogous to the Blasius formulas in incompressible flow are developed and are applied to thin symmetrical Joukowski profiles for small angles of attack.

  8. The modelling of symmetric airfoil vortex generators

    NASA Technical Reports Server (NTRS)

    Reichert, B. A.; Wendt, B. J.

    1996-01-01

    An experimental study is conducted to determine the dependence of vortex generator geometry and impinging flow conditions on shed vortex circulation and crossplane peak vorticity for one type of vortex generator. The vortex generator is a symmetric airfoil having a NACA 0012 cross-sectional profile. The geometry and flow parameters varied include angle-of-attack alfa, chordlength c, span h, and Mach number M. The vortex generators are mounted either in isolation or in a symmetric counter-rotating array configuration on the inside surface of a straight pipe. The turbulent boundary layer thickness to pipe radius ratio is delta/R = 0. 17. Circulation and peak vorticity data are derived from crossplane velocity measurements conducted at or about 1 chord downstream of the vortex generator trailing edge. Shed vortex circulation is observed to be proportional to M, alfa, and h/delta. With these parameters held constant, circulation is observed to fall off in monotonic fashion with increasing airfoil aspect ratio AR. Shed vortex peak vorticity is also observed to be proportional to M, alfa, and h/delta. Unlike circulation, however, peak vorticity is observed to increase with increasing aspect ratio, reaching a peak value at AR approx. 2.0 before falling off.

  9. Nuclear physics with spherically symmetric supernova models

    E-print Network

    M. Liebendoerfer; T. Fischer; C. Fröhlich; F. -K. Thielemann; S. Whitehouse

    2007-08-31

    Few years ago, Boltzmann neutrino transport led to a new and reliable generation of spherically symmetric models of stellar core collapse and postbounce evolution. After the failure to prove the principles of the supernova explosion mechanism, these sophisticated models continue to illuminate the close interaction between high-density matter under extreme conditions and the transport of leptons and energy in general relativistically curved space-time. We emphasize that very different input physics is likely to be relevant for the different evolutionary phases, e.g. nuclear structure for weak rates in collapse, the equation of state of bulk nuclear matter during bounce, multidimensional plasma dynamics in the postbounce evolution, and neutrino cross sections in the explosive nucleosynthesis. We illustrate the complexity of the dynamics using preliminary 3D MHD high-resolution simulations based on parameterized deleptonization. With established spherically symmetric models we show that typical features of the different phases are reflected in the predicted neutrino signal and that a consistent neutrino flux leads to electron fractions larger than 0.5 in neutrino-driven supernova ejecta.

  10. Transformations between symmetric sets of quantum states

    E-print Network

    Vedran Dunjko; Erika Andersson

    2012-06-22

    We investigate probabilistic transformations of quantum states from a `source' set to a `target' set of states. Such transforms have many applications. They can be used for tasks which include state-dependent cloning or quantum state discrimination, and as interfaces between systems whose information encodings are not related by a unitary transform, such as continuous-variable systems and finite-dimensional systems. In a probabilistic transform, information may be lost or leaked, and we explain the concepts of leak and redundancy. Following this, we show how the analysis of probabilistic transforms significantly simplifies for symmetric source and target sets of states. In particular, we give a simple linear program which solves the task of finding optimal transforms, and a method of characterizing the introduced leak and redundancy in information-theoretic terms. Using the developed techniques, we analyse a class of transforms which convert coherent states with information encoded in their relative phase to symmetric qubit states. Each of these sets of states on their own appears in many well studied quantum information protocols. Finally, we suggest an asymptotic realization based on quantum scissors.

  11. Single Molecule Electronics and Devices

    PubMed Central

    Tsutsui, Makusu; Taniguchi, Masateru

    2012-01-01

    The manufacture of integrated circuits with single-molecule building blocks is a goal of molecular electronics. While research in the past has been limited to bulk experiments on self-assembled monolayers, advances in technology have now enabled us to fabricate single-molecule junctions. This has led to significant progress in understanding electron transport in molecular systems at the single-molecule level and the concomitant emergence of new device concepts. Here, we review recent developments in this field. We summarize the methods currently used to form metal-molecule-metal structures and some single-molecule techniques essential for characterizing molecular junctions such as inelastic electron tunnelling spectroscopy. We then highlight several important achievements, including demonstration of single-molecule diodes, transistors, and switches that make use of electrical, photo, and mechanical stimulation to control the electron transport. We also discuss intriguing issues to be addressed further in the future such as heat and thermoelectric transport in an individual molecule. PMID:22969345

  12. A geometrical relation between symmetric operators and mutually unbiased operators

    E-print Network

    Amir Kalev

    2013-05-26

    In this work we study the relation between the set of symmetric operators and the set of mutually unbiased operators from finite plane geometry point of view. Here symmetric operators are generalization of symmetric informationally complete probability-operator measurements (SIC POMs), while mutually unbiased operators are the operator generalization of mutually unbiased bases (MUB). We also discuss the implication of this relation to the particular cases of rank-1 SIC POMs and MUB.

  13. Discovery of single top quark production

    SciTech Connect

    Gillberg, Dag

    2009-05-01

    The top quark is by far the heaviest known fundamental particle with a mass nearing that of a gold atom. Because of this strikingly high mass, the top quark has several unique properties and might play an important role in electroweak symmetry breaking - the mechanism that gives all elementary particles mass. Creating top quarks requires access to very high energy collisions, and at present only the Tevatron collider at Fermilab is capable of reaching these energies. Until now, top quarks have only been observed produced in pairs via the strong interaction. At hadron colliders, it should also be possible to produce single top quarks via the electroweak interaction. Studies of single top quark production provide opportunities to measure the top quark spin, how top quarks mix with other quarks, and to look for new physics beyond the standard model. Because of these interesting properties, scientists have been looking for single top quarks for more than 15 years. This thesis presents the first discovery of single top quark production. An analysis is performed using 2.3 fb{sup -1} of data recorded by the D0 detector at the Fermilab Tevatron Collider at centre-of-mass energy {radical}s = 1.96 TeV. Boosted decision trees are used to isolate the single top signal from background, and the single top cross section is measured to be {sigma}(p{bar p} {yields} tb + X, tqb + X) = 3.74{sub -0.74}{sup +0.95} pb. Using the same analysis, a measurement of the amplitude of the CKM matrix element V{sub tb}, governing how top and b quarks mix, is also performed. The measurement yields: |V{sub tb}|f{sub 1}{sup L}| = 1.05{sub -0.12}{sup +0.13}, where f{sub 1}{sup L} is the left-handed Wtb coupling. The separation of signal from background is improved by combining the boosted decision trees with two other multivariate techniques. A new cross section measurement is performed, and the significance for the excess over the predicted background exceeds 5 standard deviations.

  14. Small molecules from the decomposition of interstellar carbons

    NASA Astrophysics Data System (ADS)

    Duley, W. W.; Zaidi, A.; Wesolowski, M. J.; Kuzmin, S.

    2015-02-01

    We have studied the molecular products of the photo-induced decomposition of hydrogenated amorphous carbon (HAC) and solid hexane, C6H14, using mass spectroscopy. Mass spectra of HAC are dominated by simple hydrocarbon molecules having fewer than four carbon atoms. Notable products include C3H2, phenyl, C6H5, benzene, C6H6, and a variety of partially dehydrogenated alkane molecules with the composition CnH2n-1. Hexane, chosen as a representative solid alkane, has a more complex mass spectrum which includes Cn and a number of hydrocarbon molecules with up to 10 carbon atoms. As alkyl radicals, CnH2n-1, are commonly found in the decomposition of alkanes, we have used high precision density functional theory to simulate the infrared spectrum of 1-, 2-, and 3-hexyl radicals as well as that of the 3-hexyl ion, C6H13+. The latter could be detectable in interstellar/circumstellar sources via a strong feature at 3.66 ?m. The appearance of C3H2 as a decomposition product of photodissociated HAC may be related to the ubiquitous presence of c-C3H2 in the interstellar medium. The production of such molecules in the interstellar medium through a `top-down' chemistry deriving from the decomposition of HAC is discussed.

  15. Tevatron Top-Quark Combinations and World Top-Quark Mass Combination

    E-print Network

    Reinhild Yvonne Peters; on behalf of the ATLAS; CDF; CMS; D0 collaborations

    2014-11-04

    Almost 20 years after its discovery, the top quark is still an interesting particle, undergoing precise investigation of its properties. For many years, the Tevatron proton antiproton collider at Fermilab was the only place to study top quarks in detail, while with the recent start of the LHC proton proton collider a top quark factory has opened. An important ingredient for the full understanding of the top quark is the combination of measurements from the individual experiments. In particular, the Tevaton combinations of single top-quark cross sections, the ttbar production cross section, the W helicity in top-quark decays as well as the Tevatron and the world combination of the top-quark mass are discussed.

  16. Quantum transport through aromatic molecules

    SciTech Connect

    Ojeda, J. H., E-mail: judith.ojeda@uptc.edu.co [Instituto de Alta investigación, Universidad de Tarapaca, Casilla 7D Arica (Chile); Grupo de Física de Materiales, Escuela de Física, Universidad Pedagógica y Tecnológica de Colombia, Tunja (Colombia); Rey-González, R. R. [Departamento de Física, Universidad Nacional de Colombia, Bogotá D. C. (Colombia); Laroze, D. [Instituto de Alta investigación, Universidad de Tarapaca, Casilla 7D Arica (Chile)

    2013-12-07

    In this paper, we study the electronic transport properties through aromatic molecules connected to two semi-infinite leads. The molecules are in different geometrical configurations including arrays. Using a nearest neighbor tight-binding approach, the transport properties are analyzed into a Green's function technique within a real-space renormalization scheme. We calculate the transmission probability and the Current-Voltage characteristics as a function of a molecule-leads coupling parameter. Our results show different transport regimes for these systems, exhibiting metal-semiconductor-insulator transitions and the possibility to employ them in molecular devices.

  17. Covariant approach for perturbations of rotationally symmetric spacetimes

    SciTech Connect

    Clarkson, Chris [Cosmology and Gravity Group, Department of Mathematics and Applied Mathematics, University of Cape Town, Rondebosch 7701, Cape Town (South Africa)

    2007-11-15

    We present a covariant decomposition of Einstein's field equations which is particularly suitable for perturbations of spherically symmetric - and general locally rotationally symmetric - spacetimes. Based upon the utility of the 1+3 covariant approach to perturbation theory in cosmology, the semi-tetrad, 1+1+2 approach presented here should be useful for analyzing perturbations of a variety of systems in a covariant and gauge-invariant manner. Such applications range from stellar objects to cosmological models such as the spherically symmetric Lemaitre-Tolman-Bondi solutions or the class of locally rotationally symmetric Bianchi models.

  18. SelInv - An Algorithm for Selected Inversion of a Sparse Symmetric Matrix

    SciTech Connect

    Lin, Lin; Yang, Chao; Meza, Juan C.; Lu, Jianfeng; Ying, Lexing; E, Weinan

    2009-10-16

    We describe an efficient implementation of an algorithm for computing selected elements of a general sparse symmetric matrix A that can be decomposed as A = LDL^T, where L is lower triangular and D is diagonal. Our implementation, which is called SelInv, is built on top of an efficient supernodal left-looking LDL^T factorization of A. We discuss how computational efficiency can be gained by making use of a relative index array to handle indirect addressing. We report the performance of SelInv on a collection of sparse matrices of various sizes and nonzero structures. We also demonstrate how SelInv can be used in electronic structure calculations.

  19. THE TOP QUARK, QCD, AND NEW PHYSICS.

    SciTech Connect

    DAWSON,S.

    2002-06-01

    The role of the top quark in completing the Standard Model quark sector is reviewed, along with a discussion of production, decay, and theoretical restrictions on the top quark properties. Particular attention is paid to the top quark as a laboratory for perturbative QCD. As examples of the relevance of QCD corrections in the top quark sector, the calculation of e{sup +}e{sup -} + t{bar t} at next-to-leading-order QCD using the phase space slicing algorithm and the implications of a precision measurement of the top quark mass are discussed in detail. The associated production of a t{bar t} pair and a Higgs boson in either e{sup +}e{sup -} or hadronic collisions is presented at next-to-leading-order QCD and its importance for a measurement of the top quark Yulrawa coupling emphasized. Implications of the heavy top quark mass for model builders are briefly examined, with the minimal supersymmetric Standard Model and topcolor discussed as specific examples.

  20. Malachite green mediates homodimerization of antibody VL domains to form a fluorescent ternary complex with singular symmetric interfaces

    PubMed Central

    Szent-Gyorgyi, Chris; Stanfield, Robyn L.; Andreko, Susan; Dempsey, Alison; Ahmed, Mushtaq; Capek, Sara; Waggoner, Alan; Wilson, Ian A.; Bruchez, Marcel P.

    2013-01-01

    We report that a symmetric small molecule ligand mediates the assembly of antibody light chain variable domains (VLs) into a correspondent symmetric ternary complex with novel interfaces. The L5* Fluorogen Activating Protein (FAP) is a VL domain that binds malachite green dye (MG) to activate intense fluorescence. Crystallography of liganded L5* reveals a 2:1 protein:ligand complex with inclusive C2 symmetry, where MG is almost entirely encapsulated between an antiparallel arrangement of the two VL domains. Unliganded L5* VL domains crystallize as a similar antiparallel VL/VL homodimer. The complementarity determining regions (CDRs) are spatially oriented to form novel VL/VL and VL/ligand interfaces that tightly constrain a propeller conformer of MG. Binding equilibrium analysis suggests highly cooperative assembly to form a very stable VL/MG/VL complex, such that MG behaves as a strong chemical inducer of dimerization. Fusion of two VL domains into a single protein tightens MG binding over 1,000-fold to low picomolar affinity without altering the large binding enthalpy, suggesting that bonding interactions with ligand and restriction of domain movements make independent contributions to binding. Fluorescence activation of a symmetrical fluorogen provides a selection mechanism for the isolation and directed evolution of ternary complexes where unnatural symmetric binding interfaces are favored over canonical antibody interfaces. As exemplified by L5*, these self-reporting complexes may be useful as modulators of protein association or as high affinity protein tags and capture reagents. PMID:23978698

  1. Self-assembly of active colloidal molecules with dynamic function

    NASA Astrophysics Data System (ADS)

    Soto, Rodrigo; Golestanian, Ramin

    2015-05-01

    Catalytically active colloids maintain nonequilibrium conditions in which they produce and deplete chemicals and hence effectively act as sources and sinks of molecules. While individual colloids that are symmetrically coated do not exhibit any form of dynamical activity, the concentration fields resulting from their chemical activity decay as 1 /r and produce gradients that attract or repel other colloids depending on their surface chemistry and ambient variables. This results in a nonequilibrium analog of ionic systems, but with the remarkable novel feature of action-reaction symmetry breaking. We study solutions of such chemically active colloids in dilute conditions when they join up to form molecules via generalized ionic bonds and discuss how we can achieve structures with time-dependent functionality. In particular, we study a molecule that adopts a spontaneous oscillatory pattern of conformations and another that exhibits a run-and-tumble dynamics similar to bacteria. Our study shows that catalytically active colloids could be used for designing self-assembled structures that possess dynamical functionalities that are determined by their prescribed three-dimensional structures, a strategy that follows the design principle of proteins.

  2. Direct Measurement and Chemical Speciation of Top Ring Zone Liquid During Engine Operation

    SciTech Connect

    Splitter, Derek A [ORNL; Burrows, Barry Clay [University of Alabama, Tuscaloosa; Lewis Sr, Samuel Arthur [ORNL

    2015-01-01

    The present manuscript consists of proof of concept experiments involving direct measurements and detailed chemical speciation from the top ring zone of a running engine. The work uses a naturally aspirated single cylinder utility engine that has been modified to allow direct liquid sample acquisition from behind the top ring. Samples were analyzed and spectated using gas chromatographic techniques. Results show that the liquid mixture in the top ring zone is neither neat lubricant nor fuel but a combination of the two with unique chemical properties. At the tested steady state no-load operating condition, the chemical species of the top ring zone liquid were found to be highly dependent on boiling point, where both low reactivity higher boiling point fuel species and lubricant are observed to be the dominant constituents. The results show that at least for the tested condition, approximately 25% of the top ring zone is comprised of gasoline fuel like molecules, which are dominated by high octane number aromatic species, while the remainder of the liquid is comprised of lubricant like species.

  3. Surface chemistry of deuterated molecules

    NASA Astrophysics Data System (ADS)

    Tielens, A. G. G. M.

    1983-03-01

    The chemical composition of grain mantles is calculated in order to determine the concentration of deuterated molecules relative to their hydrogenated counterparts in grain mantles. The computation takes into account reactions involving deuterium in the gas phase and on grain surfaces. The results show that the abundance of deuterium molecules in grain mantles is much higher than expected on the basis of the cosmic abundance ratio of D to H. HDCO has a relatively high abundance in grain mantles as compared to other deuterated molecules, due to the fact that H abstraction from HDCO has a lower activation barrier than D abstraction. The infrared characteristics of the calculated grain mantles are discussed and observational tests of the model calcultions are suggested. The contribution of grain surface chemistry to the concentration of molecules in the gas phase is briefly considered.

  4. Fluorescence Microscopy of Single Molecules

    ERIC Educational Resources Information Center

    Zimmermann, Jan; van Dorp, Arthur; Renn, Alois

    2004-01-01

    The investigation of photochemistry and photophysics of individual quantum systems is described with the help of a wide-field fluorescence microscopy approach. The fluorescence single molecules are observed in real time.

  5. Molecular biomechanics of collagen molecules

    E-print Network

    Chang, Shu-Wei

    Collagenous tissues, made of collagen molecules, such as tendon and bone, are intriguing materials that have the ability to respond to mechanical forces by altering their structures from the molecular level up, and convert ...

  6. Shape resonances in ion-molecule reaction

    NASA Astrophysics Data System (ADS)

    Sakimoto, Kazuhiro

    2014-01-01

    A simple analytical formula for the probability of reaction in low-energy ion-molecule collisions is given by Wentzel-Kramers-Brillouin and uniform approximations. By using this formula, one can deal with any type of shape resonances regardless of whether the collision energy is below or above a potential barrier. The reaction probability is completely determined by three parameters: the high-energy limit (P0) of the reaction probability obtained at a collision energy much above the potential barrier, a universal measure (?) of the difference between the collision energy and the barrier top, and a scattering phase shift (?) due to short-range reactive interaction. It is very useful to draw a topographical map of the reaction probability by assuming that P0 is given as a constant and that (?, ?) are independent variables. The energy dependence of the reaction probability in a collision process is represented by the section view along a route actually allowed on this topographical map. A resonance structure appears when the actual route crosses a prominent mountain ridge. It is shown that the reaction probability can be unity at a resonance energy even if the probabilities at off-resonance energies are very small. No sharp tunnelling resonance would be expected in the collision system having P_{0}>2(\\sqrt{2}-1)=0.828.

  7. Precision Determination of the Top Quark Mass

    SciTech Connect

    Movilla Fernandez, Pedro A.; /LBL, Berkeley

    2007-05-01

    The CDF and D0 collaborations have updated their measurements of the mass of the top quark using proton-antiproton collisions at {radical}s = 1.96 TeV produced at the Tevatron. The uncertainties in each of the top-antitop decay channels have been reduced. The new Tevatron average for the mass of the top quark based on about 1 fb{sup -1} of data per experiment is 170.9 {+-} 1.8 GeV/c{sup 2}.

  8. Top Quark Properties from the Tevatron

    E-print Network

    M. Klute

    2006-05-15

    This report describes latest measurements and studies of top quark properties from the Tevatron in RunII with an integrated luminosity of up to 750pb-1. Due to its large mass of about 172GeV, the top quark provides a unique environment for tests of the Standard Model and is believed to yield sensitivity to new physics beyond the Standard Model. With data samples of close to 1fb-1 the CDF and D0 collaborations at the Tevatron enter a new aera of precision top quark measurements.

  9. Top quark mass measurement at the Tevatron

    SciTech Connect

    Guimaraes da Costa, Joao; /Harvard U.

    2004-12-01

    The authors report on the latest experimental measurements of the top quark mass by the CDF and D0 Collaborations at the Fermilab Tevatron. They present a new top mass measurement using the t{bar t} events collected by the D0 Collaboration in Run I between 1994 and 1996. This result is combined with previous measurements to yield a new world top mass average. They also describe several preliminary results using up to 193 pb{sup -1} of t{bar t} events produced in {bar p}p collisions at {radical}s = 1.96 TeV during the Run II of the Tevatron.

  10. Top quark properties from the Tevatron

    SciTech Connect

    Klute, Markus; /MIT, LNS

    2006-05-01

    This report describes latest measurements and studies of top quark properties from the Tevatron in Run II with an integrated luminosity of up to 750 pb{sup -1}. Due to its large mass of about 172 GeV/c{sup 2}, the top quark provides a unique environment for tests of the Standard Model and is believed to yield sensitivity to new physics beyond the Standard Model. With data samples of close to 1 fb{sup -1} the CDF and D0 collaborations at the Tevatron enter a new area of precision top quark measurements.

  11. Single Top Quark Measurements at the Tevatron

    E-print Network

    Manfredi Ronzani; for the CDF; D0 collaborations

    2014-12-01

    This paper reports the most recent measurements of single top quark production performed by CDF and D0 collaborations in proton-antiproton collisions at Tevatron. Events are selected in the lepton+jets final state by CDF and D0 and in the missing transverse energy plus jets final state by CDF. The small single top signal in s-channel, t-channel and inclusive s+t channel is separated from the large background by using different multivariate techniques. We also present the most recent results on extraction of the CKM matrix element $|V_{tb}|$ from the single top quark cross section.

  12. Single Top Production at the Tevatron

    SciTech Connect

    Wu, Zhenbin; /Baylor U.

    2012-05-01

    We present recent results of single top quark production in the lepton plus jet final state, performed by the CDF and D0 collaborations based on 7.5 and 5.4 fb{sup -1} of p{bar p} collision data collected at {radical}s = 1.96 TeV from the Fermilab Tevatron collider. Multivariate techniques are used to separate the single top signal from the backgrounds. Both collaborations present measurements of the single top quark cross section and the CKM matrix element |V{sub tb}|. A search for anomalous Wtb coupling from D0 is also presented.

  13. Single top quark production at D0

    SciTech Connect

    Jabeen, S.; /Boston U.

    2008-07-01

    We present first evidence for the production of single top quarks at the Fermilab Tevatron p{bar p} collider. Using a 0.9 fb{sup -1} dataset, we apply a multivariate analysis to separate signal from background and measure cross section for single top quark production. We use the cross section measurement to directly determine the CKM matrix element that describes the Wtb coupling. We also present results of W0 and charged Higgs searches with the same final states as standard model single top quark production.

  14. Top Quark Production at the Tevatron

    SciTech Connect

    Mietlicki, David J.

    2011-12-01

    The top quark is the most recently discovered of the standard model quarks, and because of its very large mass, studies of the top quark and its interactions are important both as tests of the standard model and searches for new phenomena. In this document, recent results of analyses of top quark production, via both the electroweak and strong interactions, from the CDF and D0 experiments are presented. The results included here utilize a dataset corresponding to up to 6 fb{sup -1} of integrated luminosity, slightly more than half of the dataset recorded by each experiment before the Tevatron was shutdown in September 2011.

  15. Single Top Production at the Tevatron

    E-print Network

    Zhenbin Wu

    2012-05-16

    We present recent results of single top quark production in the lepton plus jet final state, performed by the CDF and D0 collaborations based on 7.5 and 5.4/fb of ppbar collision data collected at sqrt(s) = 1.96 TeV from the Fermilab Tevatron collider. Multivariate techniques are used to separate the single top signal from the backgrounds. Both collaborations present measurements of the single top quark cross section and the CKM matrix element Vtb. A search for anomalous Wtb coupling from D0 is also presented.

  16. Top-quark mass at hadron colliders

    E-print Network

    Andrea Castro

    2014-09-02

    Top quarks can be produced abundantly at hadron colliders like the Tevatron at Fermilab and the Large Hadron Collider at CERN, and a variety of measurements of top-quark properties have been gathered in the recent years from four experiments: CDF and D0 at the Tevatron and ATLAS and CMS at the Large Hadron Collider. In this review the most recent results on the measurement of the top-quark mass by the four different collaborations, with various techniques and considering different topologies, are reported.

  17. Top quark physics at the Tevatron

    SciTech Connect

    Pleier, M.A.; /Bonn U.

    2007-09-01

    The Tevatron proton-antiproton collider at Fermilab with its centre of mass energy of 1.96 TeV is currently the only source for the production of top quarks. Its increased luminosity and centre of mass energy in Run II allow both collider detectors CDF and D0 to study top quarks with unprecedented scrutiny. Recent results on the top quark's pair production cross section and its properties such as mass, electric charge, helicity of the W boson in its decay and branching fraction B(t {yields} Wb) are presented and probe the validity of the Standard Model.

  18. Effect of LaNiO3 Top Electrode on the Resistance of Pb(Zr,Ti)O3 Ferroelectric Capacitor to Hydrogen Damage and Fatigue

    Microsoft Academic Search

    Dong-Chun Kim; Won-Jong Lee

    2002-01-01

    The polarization hysteresis characteristics of Pb(Zr,Ti)O3 (PZT) capacitors with a Pt top electrode are degraded by annealing in a hydrogen-containing environment due to the catalytic effect of Pt. This degradation can be avoided by adopting an LaNiO3 (LNO) conductive film as a top electrode. The LNO film does not act as a catalyst for the dissociation of hydrogen molecules and

  19. How far the postorogenic extensional tectonics in the Aegean domain is symmetric?

    NASA Astrophysics Data System (ADS)

    Augier, Romain; Jolivet, Laurent; Gadenne, Leslie; Driussi, Olivier

    2013-04-01

    Current models to explain the finite geometry of the Aegean domain and the exhumation of the eclogite-bearing HP rocks in the Aegean domain rely on the recognition of a synorogenic exhumation regime followed by a postorogenic back-arc extension. A first generation of low-angle normal faults (LANF) developed during the subduction and the formation of the Hellenic Eocene orogenic wedge contemporaneously with the overthrusting of the Cycladic Blueschists over basement units. Other LANF were formed subsequently and accompanied the development of Metamorphic Core Complexes (MCC) during the collapse of the internal zones in the back-arc domain. Most of the stretching during postorogenic extension was accommodated by N-dipping LANF with N- to NE-sense of shear pertaining to the North Cycladic Detachment System (NCDS). More recently, the description of the top-to-the-south West Cycladic Detachment System (WCDS) resulted in a more symmetrical character of the postorogenic extension. However, the transition in time and space between these major structures, particularly the NCDS and the WCDS, which is a key question to understand the dynamics of the back-arc extension, remains widely unclear. The Folegandros-Sikinos area, whose tectonometamorphic evolution appears poorly constrained, is however quite exemplary of this discussion. Located to the south of the Cycladic Archipelago, at short distance from the WCDS last outcrop in Serifos Island, this area offers the opportunity to study both the synorogenic deformation preserved at the vicinity of the Cycladic basement and the structural transition between areas characterised by top-to-the-North and top-to-the-South kinematics during the postorogenic history. Based on an extensive field survey making the link between kinematics of the noncoaxial deformation and changing metamorphic conditions, we show that (1) a E-W syn-blueschists facies deformation is preserved within the HP lenses; (2) a penetrative, post-blueschists facies top-to-the-North sense of shear is present throughout the study area and (3) deformation that concentrates in the vicinity of the contact with the Cycladic basement is only characterized by a top-to-the-North kinematics. These results imply (4) the activity of a major postorogenic LANF roofing the Cycladic Blueschists (5) and the complete overprint of initial top-to-the-South thrust kinematics by top-to-the-North ones over the contact with the Cycladic basement that are consistent with a strong asymmetry of the deformation. Only a late, localized ductile-brittle deformation is recognized and thus ascribed to the activity of the WCDS to the West of the study area. LANF dipping in opposite directions with opposite sense of shear are then restricted to the west of Sifnos Island and separated from the central Cyclades by a sharp transition, highlighting a highly non-cylindrical deformation. Asymmetry of the postorogenic extension could be correlated with the amount of stretching. Rather symmetric deformation seems to occur in marginal areas of the domain while asymmetric deformation is encountered within highly-extended areas where lower crustal material is exhumed within MCCs.

  20. Cracked shells under skew-symmetric loading

    NASA Technical Reports Server (NTRS)

    Lelale, F.

    1982-01-01

    A shell containing a through crack in one of the principal planes of curvature and under general skew-symmetric loading is considered. By employing a Reissner type shell theory which takes into account the effect of transverse shear strains, all boundary conditions on the crack surfaces are satisfied separately. Consequently, unlike those obtained from the classical shell theory, the angular distributions of the stress components around the crack tips are shown to be identical to the distributions obtained from the plane and antiplane elasticity solutions. Extensive results are given for axially and circumferentially cracked cylindrical shells, spherical shells, and toroidal shells under uniform inplane shearing, out of plane shearing, and torsion. The effect of orthotropy on the results is also studied.

  1. Expanding Spherically Symmetric Models without Shear

    E-print Network

    Sunil D Maharaj; Peter GL Leach; Roy Maartens

    1995-11-27

    The integrability properties of the field equation $L_{xx} = F(x)L^2$ of a spherically symmetric shear--free fluid are investigated. A first integral, subject to an integrability condition on $F(x)$, is found, giving a new class of solutions which contains the solutions of Stephani (1983) and Srivastava (1987) as special cases. The integrability condition on $F(x)$ is reduced to a quadrature which is expressible in terms of elliptic integrals in general. There are three classes of solution and in general the solution of $L_{xx} = F(x)L^2$ can only be written in parametric form. The case for which $F=F(x)$ can be explicitly given corresponds to the solution of Stephani (1983). A Lie analysis of $L_{xx} = F(x) L^2$ is also performed. If a constant $\\alpha$ vanishes, then the solutions of Kustaanheimo and Qvist (1948) and of this paper are regained. For $\\alpha \

  2. Geometric inequalities for axially symmetric black holes

    E-print Network

    Sergio Dain

    2012-03-01

    A geometric inequality in General Relativity relates quantities that have both a physical interpretation and a geometrical definition. It is well known that the parameters that characterize the Kerr-Newman black hole satisfy several important geometric inequalities. Remarkably enough, some of these inequalities also hold for dynamical black holes. This kind of inequalities play an important role in the characterization of the gravitational collapse, they are closed related with the cosmic censorship conjecture. Axially symmetric black holes are the natural candidates to study these inequalities because the quasi-local angular momentum is well defined for them. We review recent results in this subject and we also describe the main ideas behind the proofs. Finally, a list of relevant open problem is presented.

  3. Spherical symmetric charged solution with cosmological constant

    E-print Network

    N. Ozdemir

    2007-11-29

    A spherically symmetric charged ideal fluid solution of Einstein field equation is given in the presence of the cosmological constant and two well known example of this type of solution is presented. If the matter is confined in a region, the exterior spacetime is considered as RN-de Sitter (Reissner-Nordstrom de Sitter) and to complete solution matching conditions are examined. We show that the function which is related to the dynamics of the system will determine the fate of the system: expansion, contraction or bouncing situations may occur for different configurations. The initial conditions of the matter determine the final form of the system and therefore the nature of the singularities in the presence of the electric charge and the cosmological constant is examined to reveal their effects on the singularity formation during collapse.

  4. Implications of nonlinearity for spherically symmetric accretion

    E-print Network

    Sen, Sourav

    2012-01-01

    Stationary solutions of spherically symmetric accretion processes have been subjected to a time-dependent radial perturbation, whose equation includes nonlinearity to any arbitrary order. Regardless of the order of nonlinearity, the equation of the perturbation bears a form that is remarkably similar to the metric equation of an analogue acoustic black hole. Casting the perturbation as a standing wave and maintaining nonlinearity in it up to the second order, brings out the time-dependence of the perturbation in the form of a Lienard system. A dynamical systems analysis of this Lienard system reveals a saddle point in real time, with the implication that instabilities will develop in the accreting system when the perturbation is extended into the nonlinear regime. The instability of initial subsonic states may also adversely affect the temporal evolution of the flow towards a final stable transonic state.

  5. VACUUM calculation in azimuthally symmetric geometry

    SciTech Connect

    Chance, M.S.

    1996-11-01

    A robustly accurate and effective method is presented to solve Laplace`s equation in general azimuthally symmetric geometry for the magnetic scalar potential in the region surrounding a plasma discharge which may or may not contain external conducting shells. These shells can be topologically toroidal or spherical, and may have toroidal gaps in them. The solution is incorporated into the various MHD stability codes either through the volume integrated perturbed magnetic energy in the vacuum region or through the continuity requirements for the normal component of the perturbed magnetic field and the total perturbed pressure across the unperturbed plasma-vacuum boundary. The method is based upon using Green`s second identity and the method of collocation. As useful byproducts, the eddy currents and the simulation of Mirnov loop measurements are calculated.

  6. General spherically symmetric elastic stars in Relativity

    E-print Network

    I. Brito; J. Carot; E. G. L. R. Vaz

    2009-11-07

    The relativistic theory of elasticity is reviewed within the spherically symmetric context with a view towards the modeling of star interiors possessing elastic properties such as theones expected in neutron stars. Emphasis is placed on generality in the main sections of the paper, and the results are then applied to specific examples. Along the way, a few general results for spacetimes admitting isometries are deduced, and their consequences are fully exploited in the case of spherical symmetry relating them next to the the case in which the material content of the spacetime is some elastic material. This paper extends and generalizes the pioneering work by Magli and Kijowski [1], Magli [2] and [3], and complements, in a sense, that by Karlovini and Samuelsson in their interesting series of papers [4], [5] and [6].

  7. Duality symmetric string and M-theory

    NASA Astrophysics Data System (ADS)

    Berman, David S.; Thompson, Daniel C.

    2015-03-01

    We review recent developments in duality symmetric string theory. We begin with the world-sheet doubled formalism which describes strings in an extended spacetime with extra coordinates conjugate to winding modes. This formalism is T-duality symmetric and can accommodate non-geometric T-fold backgrounds which are beyond the scope of Riemannian geometry. Vanishing of the conformal anomaly of this theory can be interpreted as a set of spacetime equations for the background fields. These equations follow from an action principle that has been dubbed Double Field Theory (DFT). We review the aspects of generalised geometry relevant for DFT. We outline recent extensions of DFT and explain how, by relaxing the so-called strong constraint with a Scherk-Schwarz ansatz, one can obtain backgrounds that simultaneously depend on both the regular and T-dual coordinates. This provides a purely geometric higher dimensional origin to gauged supergravities that arise from non-geometric compactification. We then turn to M-theory and describe recent progress in formulating an En(n) U-duality covariant description of the dynamics. We describe how spacetime may be extended to accommodate coordinates conjugate to brane wrapping modes and the construction of generalised metrics in this extended space that unite the bosonic fields of supergravity into a single object. We review the action principles for these theories and their novel gauge symmetries. We also describe how a Scherk-Schwarz reduction can be applied in the M-theory context and the resulting relationship to the embedding tensor formulation of maximal gauged supergravities.

  8. VIEW OF PDP TANK TOP, LEVEL 0?, WITH LTR TANK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF PDP TANK TOP, LEVEL 0?, WITH LTR TANK TOP ON LEFT, LOOKING NORTHEAST. CRANE AND VERTICAL HOISTING ELEMENTS AT TOP - Physics Assembly Laboratory, Area A/M, Savannah River Site, Aiken, Aiken County, SC

  9. VIEW OF PDP TANK TOP, LEVEL 0?, WITH VERTICAL ELEMENTS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF PDP TANK TOP, LEVEL 0?, WITH VERTICAL ELEMENTS IN BACKGROUND, LTR TANK TOP ON LEFT, AND SHEAVE RACK ELEMENTS AT TOP, LOOKING NORTH - Physics Assembly Laboratory, Area A/M, Savannah River Site, Aiken, Aiken County, SC

  10. Synthesis and Physical Properties of Symmetrical and Non-symmetrical Triacylglycerols Containing Two Palmitic Fatty Acids

    Microsoft Academic Search

    R. O. Adlof; G. R. List

    2008-01-01

    A series of symmetrical (ABA) and non-symmetrical (AAB) triacylglycerol (TAG) isomers containing “A,” palmitic (P; 16:0) acid,\\u000a and “B,” either oleic (O; 9c-18:1), elaidic (E; 9t-18:1), linoleic (L; 9c,12c-18:2) or linolenic (Ln; 9c,12c,15c-18:3) fatty\\u000a acids were synthesized by esterification of the thermodynamically more-stable 1,3-di- or 1(3)-monoacylglycerols [1,3-DAG or\\u000a 1(3)-MAG], respectively. 1,3-dipalmitoylglycerol (1,3P-DAG) was esterified with O, L or Ln acid

  11. Electronic control inside a molecule : towards single molecule devices

    NASA Astrophysics Data System (ADS)

    Lastapis, Mathieu; Fukuma, Yurie; Boland, John

    2006-03-01

    The chimerical single molecule engineering has been proven to be accessible through the use of scanning tunnelling microscopy (STM) [1]. In this field, one particularly attractive area is the study of single molecules adsorbed on semiconductor surfaces. It has been recently demonstrated that a spatial fine control of the molecular dynamics is possible through the use of tunnelling current [2]. In order to improve the electronic control of a single molecule, we are currently investigating a promising system: CaF2 on Si(111). This system has been extensively studied as a model system to deposit insulator on silicon. Here we are using this system to electronically decouple the molecule from the substrate. I will present LT STM experiments on atomically thick CaF islands on Si(111). The measured electronic properties of these islands demonstrate their potential as ideal templates to study single molecules. Finally I will present some preliminary results on N-HBC [3] adsorbed on a CaF island. [1] G. Binnig and H. Rohrer, ``In touch with atoms'', Rev. Mod. Phys. 71, S324-S330 (1999) [2] M. Lastapis et al, Science, 308, 1000 (2005) [3] S.Draper et al, JACS, 126, 8694 (2004)

  12. Theme: Women Reach for the Top.

    ERIC Educational Resources Information Center

    Ducci, Maria Angelica; And Others

    1993-01-01

    Includes "Women in Authority: The Ideal and the Reality" (Ducci); "Unequal Race to the Top"; "What Training for Career Advancement?" (Fromont); "Motherhood, Family, Career" (Seguret); and "It's Up to Women to Make Things Change." (JOW)

  13. Exotic top partners and Little Higgs

    E-print Network

    Kearney, John

    Little Higgs models often give rise to top partners beyond the minimal ones necessary for the cancellation of quadratic divergences. We review how this occurs and discuss the phenomenology of these exotic states. We emphasize ...

  14. Top 5 Hidden Hazards in the Home

    MedlinePLUS

    ... Neighborhood Safety Network Community Outreach Resource Center CO Poster Contest Toy Recall Statistics Pool Safely Home / Safety Education / Neighborhood Safety Network / Posters En Español Top 5 Hidden Home Hazards Magnets, ...

  15. Top quark physics with ATLAS and CMS

    SciTech Connect

    Onofre, A. [LIP, Departamento de Fisica, Universidade de Coimbra, 3004-516 Coimbra (Portugal)

    2009-12-17

    The potential of the ATLAS and CMS experiments for studying top quark physics at the LHC is reviewed. The measurements of the tt-bar production cross section and spin correlations, the top quark mass, its electric charge, the structure of the W tb vertex and the measurement of the W boson helicities, the sensitivity to anomalous couplings, top quark rare decays through Flavour Changing Neutral Currents and the single top quark production are discussed. The results shown use the fall Monte Carlo simulation of ATLAS and CMS and assume a center of mass energy of 14 TeV at the LHC. Integrated luminosities in the range between B(10 bp{sup -1}) and B(10 fb{sup -1}) are considered, depending on the physics observables under study.

  16. Manifestations of top compositeness at colliders.

    SciTech Connect

    Kumar, K.; Tait, T. M. P.; Vega-Morales, R.; High Energy Physics; Northwestern Univ.

    2009-01-01

    We explore the possibility that the right-handed top quark is composite, identifying possible signatures of compositeness and how they might manifest themselves at the LHC and Tevatron. We perform a complete analysis of the dimension six modifications of the top coupling to gluons and find that cancellations among operators in the t{bar t} rate allow for very low compositeness scales, but this can be drastically improved by looking at kinematic distributions. Turning to the LHC, we examine four top production from a dimension six four-top operator and estimate the LHC with 100 fb{sup -1} collected luminosity to be sensitive to compositeness scales as high as 5 TeV.

  17. Selling Energy Conservation Projects to Top Management 

    E-print Network

    Jonsson, K. A.

    1983-01-01

    Conservation activities do not gain approval due to plant engineer's inability to properly prepare and present proposals for expenditure approval by top level management. Over the past several years the author has developed a successful format to obtain...

  18. The Strand Symmetric Model Marta Casanellas Seth Sullivant

    E-print Network

    Casanellas, Marta

    . By a strand symmetric Markov model, we mean one whose mutation structure reflects the symmetry induced by the double-stranded structure of DNA. In particular, a strand symmetric model for DNA must have the following with n taxa. First, we wish to describe the random variables associated to each vertex in the tree

  19. ON CONFORMAL KILLING SYMMETRIC TENSOR FIELDS ON RIEMANNIAN MANIFOLDS

    E-print Network

    Sharafutdinov, Vladimir

    ON CONFORMAL KILLING SYMMETRIC TENSOR FIELDS ON RIEMANNIAN MANIFOLDS N. S. DAIRBEKOV AND V. A. SHARAFUTDINOV Abstract. A vector field on a Riemannian manifold is called conformal Killing if it gen- erates one-parameter group of conformal transformation. The class of conformal Killing symmetric tensor

  20. Quantum Orders and Symmetric Spin Liquids Xiao-Gang Wen

    E-print Network

    Wen, Xiao-Gang

    . Spin-charge separation in (doped) spin liquids 4 D. Organization 6 II. Projective construction of 2DQuantum Orders and Symmetric Spin Liquids Xiao-Gang Wen Department of Physics, Massachusetts, we construct hundreds of symmetric spin liquids, which have SU(2), U(1) or Z2 gauge structures at low

  1. Quantum Orders and Symmetric Spin Liquids (the original version)

    E-print Network

    Wen, Xiao-Gang

    superconductors 3 C. Spin-charge separation in (doped) spin liquids 5 D. Organization 6 II. ProjectiveQuantum Orders and Symmetric Spin Liquids (the original version) Xiao-Gang Wen Department orders and projective symmetry groups, we construct hundreds of symmetric spin liquids, which have SU(2

  2. Random spinorbit coupling and spin relaxation in symmetric quantum wells

    E-print Network

    Sipe,J. E.

    Random spin­orbit coupling and spin relaxation in symmetric quantum wells E. Ya. Shermana of the system. It will be shown in this letter that even in quantum wells with perfectly symmetric environment of this letter is to investigate a possible minimum spin relaxation rate in quantum wells. We start

  3. HOMOGENEOUS EINSTEIN--WEYL STRUCTURES ON SYMMETRIC SPACES

    E-print Network

    Kerr, Megan M.

    ), where g is Date: February 24, 1999. 1 #12; 2 MEGAN M. KERR the Gauduchon metric. Hence we will assumeHOMOGENEOUS EINSTEIN--WEYL STRUCTURES ON SYMMETRIC SPACES MEGAN M. KERR Abstract. In this paper we) The symmetrized Ricci tensor is a multiple of the metric (\\Lambda is a function on M ). Three­dimensional compact

  4. The algorithm and application for the symmetrical routing

    Microsoft Academic Search

    Xu Zhenghua

    2011-01-01

    In the integrated circuit routing, we often consider the routing for some special nets under the restrictions, such as equidistance and symmetry. The symmetrical routing is operated between the routing for the bus and the clock and the routing for most the others without the priority. We prove that the symmetrical routing problem under the H-V model is equivalent to

  5. Symmetrical and decoupled nickel microgyroscope on insulating substrate

    Microsoft Academic Search

    Said Emre Alper; Tayfun Akin

    2004-01-01

    This paper presents a symmetrical and decoupled surface micromachined gyroscope fabricated by electroforming thick nickel on a glass substrate. The symmetric structure allows matched resonant frequencies for the drive and sense vibration modes for improved sensitivity, while the decoupled drive and sense oscillation modes prevents unstable operation due to mechanical coupling, resulting in a low zero-rate output drift. The use

  6. Secure Integration of Asymmetric and Symmetric Encryption Schemes

    E-print Network

    Pointcheval, David

    Secure Integration of Asymmetric and Symmetric Encryption Schemes Eiichiro FUJISAKI and Tatsuaki,okamotog@sucaba.isl.ntt.co.jp Abstract. This paper shows a generic and simple conversion from weak asymmetric and symmetric encryption, this conversion can be applied eÆciently to an asymmetric encryption scheme that provides a large enough coin

  7. Reconstruction of a Spherically Symmetrical Speed of Sound

    Microsoft Academic Search

    Joyce R. McLaughlin; Peter L. Polyakov; Paul E. Sacks

    1994-01-01

    Consider the inverse acoustic scattering problem for a spherically symmetric inhomogeneity of compact support that arises, among other places, in nondestructive testing. Define the corresponding homogeneous and inhomogeneous interior transmission problems, see, e.g., [D. Colton and P. Monk, Quart. J. Mech. Math., 41 (1988), pp. 97-125]. Here the authors study the subset of transmission' eigenvalues corresponding to spherically symmetric eigenfunctions

  8. Quantitative Analysis for Controllability of Symmetric Control Systems

    E-print Network

    Murota, Kazuo

    Quantitative Analysis for Controllability of Symmetric Control Systems Reiko Tanaka 1 and Kazuo with the controllability of systems possessing symmetries. In partic­ ular, we aim to give a lower bound for the number of functioning modules needed to ensure the controllability of the entire symmetric system. Our concern

  9. SYMMETRIC AUSLANDER AND BASS CATEGORIES PETER JRGENSEN AND KIRIKO KATO

    E-print Network

    Jørgensen, Peter

    SYMMETRIC AUSLANDER AND BASS CATEGORIES PETER JÃ?RGENSEN AND KIRIKO KATO Abstract. We define is set in the wider context of a theory for As (R) and Bs (R), the symmetric Bass category which as the Auslander and Bass categories of R. The precise definition is given in Remark 1.5 below, but note that A

  10. A Symmetrical Communication Interface for Distributed-Memory Computers

    Microsoft Academic Search

    Peter A. Steenkiste

    1991-01-01

    We describe the features of the Nectar communication We describe a communication interface that presents primitives: symmetrical addressing, the description of the applications with a simple model of the interlying message, and the synchronization behavior. distributed-memory system. All communication operations have the same regular format, and the send and 2.1. Addressing receive operations are completely symmetrical. For example, both sends

  11. Hierarchical Shape Description Via the Multiresolution Symmetric Axis Transform

    Microsoft Academic Search

    Stephen M. Pizer; William R. Oliver; Sandra H. Bloomberg

    1987-01-01

    A method is proposed that produces a shape description in the form of a hierarchy by scale of simple symmetric axis sequences. An axis segment that is a child of another has smaller scale and is seen as a branch of its parent. The scale value and parent-child relationship are induced by following the symmetric axis under successive reduction of

  12. Stability of Trilateral Forces: II, Large Symmetric Force

    SciTech Connect

    Canavan, G.H.

    1998-09-17

    For large symmetric offensive forces, as for small, at few weapons per missile all forces are reserved, costs are constant, and configurations are stable. At many weapons permissile, no weapons are reserved, first strike costs decrease, fractionation is attractive, and stability degrades. These results a due to symmetries that would not be degraded by additional symmetric opponents.

  13. Zero Knowledge and Soundness are Symmetric Shien Jin Ong

    E-print Network

    Vadhan, Salil

    Zero Knowledge and Soundness are Symmetric Shien Jin Ong Salil Vadhan School of Engineering having zero- knowledge argument systems. This characterization is symmetric in its treatment of the zero zero-knowledge arguments is closed under complement. Furthermore, we show that a problem in NP has

  14. OPTICAL OBSERVATION OF ROTATIONALLY SYMMETRIC LECITHIN VESICLE SHAPES

    E-print Network

    Paris-Sud XI, Université de

    727 OPTICAL OBSERVATION OF ROTATIONALLY SYMMETRIC LECITHIN VESICLE SHAPES W. HARBICH Institut für. 2014 The contours of some rotationally symmetric lecithin vesicles were photographed under a phase, Classification Physics Abstracts 7.130 Lecithin in excess water tends to separate sponta- neously into membranes

  15. On detection of outliers in symmetric normal models

    Microsoft Academic Search

    Dayanand N. Naik

    1990-01-01

    Extensions of recent results for detection of mean slippage type outliers from i.i.d. multivariate normal and elliptically symmetric distributions are made to symmetric case, that is, when the observations are equicorrelated. The main tool used is Wijsman's (1967) representation theorem. The results obtained can be viewed as a robustness property of the use of Mardia's multivariate kurtosis as a locally

  16. Estimating Symmetric, Positive Definite Matrices in Robotic Control

    E-print Network

    Chen, Yixin

    control. In robotics, the mass- inertia matrix of a robotic system is in the symmetric positive definite] and stiffness matrix directly fit into (1). The covariance matrix estimation problem and the matrix modificationEstimating Symmetric, Positive Definite Matrices in Robotic Control Yixin Chen John E. McInroy Dept

  17. Fast Algebraic Attacks and Decomposition of Symmetric Boolean Functions

    Microsoft Academic Search

    Meicheng Liu; Dongdai Lin; Dingyi Pei

    2011-01-01

    In this correspondence, first we give a decomposition of symmetric Boolean functions, then we show that almost all sym- metric Boolean functions, including these functions with good al- gebraic immunity, behave badly against fast algebraic attacks. Be- sides, we improve the relations between algebraic degree and alge- braic immunity of symmetric Boolean functions. Index Terms—Algebraic attacks, algebraic degree, algebraic im-

  18. Results on Rotation Symmetric Bent and Correlation Immune Boolean Functions

    Microsoft Academic Search

    Pantelimon Stanica; Subhamoy Maitra; John A. Clark

    2004-01-01

    Recent research shows that the class of Rotation Symmetric Boolean Functions (RSBFs), i.e., the class of Boolean functions that are invariant under circular translation of indices, are potentially rich in functions of cryptographic significance. Here we present new results regarding the Rotation Symmetric (rots) correlation immune (CI) and bent functions. We present important data structures for ecient search strategy of

  19. Modal analysis of optical fibers with symmetrically distributed nonuniform cores

    Microsoft Academic Search

    Naoto Kishi; K. Tayama; E. Yamashita

    1996-01-01

    This paper describes the modal analysis of optical fibers with symmetrically distributed multiple cores. Each core has an identical, axially symmetrical, and nonuniform refractive index profile. Group theoretical approach is applied to treat the symmetry of the waveguide structure. The point-matching method combined with the staircase-approximation method is used to take into account complex boundary conditions and complex refractive index

  20. On problem of nonlinear symmetric instability in zonal shear flow

    Microsoft Academic Search

    X. Y. Shen; Y. Q. Ni; Y. H. Ding

    2002-01-01

    This paper is focused on the problem of nonlinear symmetric instability in a baroclinic basic flow. The limited amplitude characteristics of unsteady wave were investigated with the aid of equations of adiabatic, inviscid, nonlinear symmetric disturbance and a multi-scale singular perturbation technique, Evidence suggests that the limited amplitude of unsteady wave exhibits an oscillatory trend of its intensity; the amplitude