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1

Pure rotational Raman scattering by symmetric top molecules  

Microsoft Academic Search

The distribution of intensities between the branches of the pure rotational Raman spectrum of a symmetric top molecule is calculated according to the quantum mechanical method of Placzek and Teller. The total intensities are obtained by summing over the individual line intensities associated with transitions from rotational state J,K to state J?,K?. The exact distribution depends on the temperature of

G. D. Patterson

1973-01-01

2

Critical binding and electron scattering by symmetric-top polar molecules.  

PubMed

Quantum treatments of electron interactions with polar symmetric-top rotor molecules show features not present in the treatment of the linear-polar-rotor model. For symmetric tops possessing non-zero angular momentum about the symmetry axis, a new critical dipole can be defined that guarantees an infinite set of dipole-bound states independent of the values of the components of the inertial tensor. Additionally, for this same class, the scattering cross section diverges for all nonzero values of dipole moments and inertial moments, similar to solutions for the fixed linear dipole. Additional predictions are presented for electron affinities and rotational resonances of these systems. PMID:25362310

Garrett, W R

2014-10-28

3

Directional States of Symmetric-Top Molecules Produced by Combined Static and Radiative Electric Fields  

E-print Network

We show that combined electrostatic and radiative fields can greatly amplify the directional properties, such as axis orientation and alignment, of symmetric top molecules. In our computational study, we consider all four symmetry combinations of the prolate and oblate inertia and polarizability tensors, as well as the collinear and perpendicular (or tilted) geometries of the two fields. In, respectively, the collinear or perpendicular fields, the oblate or prolate polarizability interaction due to the radiative field forces the permanent dipole into alignment with the static field. Two mechanisms are found to be responsible for the amplification of the molecules' orientation, which ensues once the static field is turned on: (a) permanent-dipole coupling of the opposite-parity tunneling doublets created by the oblate polarizability interaction in collinear static and radiative fields; (b) hybridization of the opposite parity states via the polarizability interaction and their coupling by the permanent dipole ...

Härtelt, Marko

2008-01-01

4

Extended diffusion theory of reorientation of symmetric top molecules with internal rotation  

NASA Astrophysics Data System (ADS)

The extended diffusion (ED) theory for the reorientational dynamics of a symmetric top molecule with internal rotation is reinvestigated. Based on a unified ED picture, we express, by using the convolution theorem of the Laplace transform, the reorientational correlation time with overall and internal free rotor correlation functions. In this work, Bull's "equal angular momentum correlation time assumption" for both overall and internal rotations is removed. Limiting expressions, for diffusion limit of the overall rotation, are derived and shown to reduce to the results of previous works. As an application, our numerical calculations are compared with experiments on 13C nuclear-magnetic-resonance dipolar relaxation times of toluene. Angular momentum correlation times, thus obtained from the comparison, show that our calculations agree with the previous work of Chung et al.[Chem. Phys. Lett. 93, 499 (1982)].

Jang, Joonkyung; Shin, Kook Joe

1997-05-01

5

Directional states of symmetric-top molecules produced by combined static and radiative electric fields.  

PubMed

We show that combined electrostatic and radiative fields can greatly amplify the directional properties, such as axis orientation and alignment, of symmetric top molecules. In our computational study, we consider all four symmetry combinations of the prolate and oblate inertia and polarizability tensors, as well as the collinear and perpendicular (or tilted) geometries of the two fields. In, respectively, the collinear or perpendicular fields, the oblate or prolate polarizability interaction due to the radiative field forces the permanent dipole into alignment with the static field. Two mechanisms are found to be responsible for the amplification of the molecules' orientation, which ensues once the static field is turned on: (a) permanent-dipole coupling of the opposite-parity tunneling doublets created by the oblate polarizability interaction in collinear static and radiative fields and (b) hybridization of the opposite parity states via the polarizability interaction and their coupling by the permanent dipole interaction to the collinear or perpendicular static field. In perpendicular fields, the oblate polarizability interaction, along with the loss of cylindrical symmetry, is found to preclude the wrong-way orientation, causing all states to become high-field seeking with respect to the static field. The adiabatic labels of the states in the tilted fields depend on the adiabatic path taken through the parameter space comprised of the permanent and induced-dipole interaction parameters and the tilt angle between the two field vectors. PMID:18554019

Härtelt, Marko; Friedrich, Bretislav

2008-06-14

6

Ejs Symmetric Top Model  

NSDL National Science Digital Library

The Ejs Symmetric Top model displays the motion of a top, in both the space frame and body frame, with no net toque applied. The top has an initial angular speed in the x, y, and z directions. The moments of inertia in each direction, and the initial angular positions and angular speeds can be changed via textboxes. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Symmetric Top model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_rigid_bodies_symmetric.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for rigid body dynamics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-08-18

7

Quantum effects in the capture of charged particles by dipolar polarizable symmetric top molecules. I. General axially nonadiabatic channel treatment  

NASA Astrophysics Data System (ADS)

The rate coefficients for capture of charged particles by dipolar polarizable symmetric top molecules in the quantum collision regime are calculated within an axially nonadiabatic channel approach. It uses the adiabatic approximation with respect to rotational transitions of the target within first-order charge-dipole interaction and takes into account the gyroscopic effect that decouples the intrinsic angular momentum from the collision axis. The results are valid for a wide range of collision energies (from single-wave capture to the classical limit) and dipole moments (from the Vogt-Wannier and fly-wheel to the adiabatic channel limit).

Auzinsh, M.; Dashevskaya, E. I.; Litvin, I.; Nikitin, E. E.; Troe, J.

2013-08-01

8

Molecular structure determination from x-ray scattering patterns of laser-aligned symmetric-top molecules  

SciTech Connect

We investigate the molecular structure information contained in the x-ray diffraction patterns of an ensemble of rigid CF{sub 3}Br molecules aligned by an intense laser pulse at finite rotational temperature. The diffraction patterns are calculated at an x-ray photon energy of 20 keV to probe molecular structure at angstrom-scale resolution. We find that a structural reconstruction algorithm based on iterative phase retrieval fails to extract a reliable structure. However, the high atomic number of Br compared with C or F allows each diffraction pattern to be treated as a hologram. Using this approach, the azimuthal projection of the molecular electron density about the alignment axis may be retrieved.

Ho, P. J. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Starodub, D. [Department of Physics, Arizona State University, Tempe, Arizona 85287 (United States); Saldin, D. K.; Shneerson, V. L.; Ourmazd, A. [Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201 (United States); Santra, R. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States)

2009-10-07

9

Rotational excitation of symmetric top molecules by collisions with atoms: Close coupling, coupled states, and effective potential calculations for NH3-He  

NASA Technical Reports Server (NTRS)

The formalism for describing rotational excitation in collisions between symmetric top rigid rotors and spherical atoms is presented both within the accurate quantum close coupling framework and also the coupled states approximation of McGuire and Kouri and the effective potential approximation of Rabitz. Calculations are reported for thermal energy NH3-He collisions, treating NH3 as a rigid rotor and employing a uniform electron gas (Gordon-Kim) approximation for the intermolecular potential. Coupled states are found to be in nearly quantitative agreement with close coupling results while the effective potential method is found to be at least qualitatively correct. Modifications necessary to treat the inversion motion in NH3 are discussed.

Green, S.

1976-01-01

10

Reduction of T*SE(3) to the Poisson structure for a symmetric top  

E-print Network

Symmetrical top is a special case of a general top. The canonical Poisson structure on T*SE(3) is the common method of its description. This Poisson structure is invariant under the right action of SO(3). However the Hamiltonian of the symmetrical top is only invariant under the right action of the subgroup S1 that corresponds to the rotation around the top symmetry axis. Then the Poisson structure for a symmetric top is obtained by reduction T*SE(3)/S1 is shown.

Stanislav S. Zub; Sergiy I. Zub

2014-03-12

11

Strain-Induced Formation of Fourfold Symmetric SiGe Quantum Dot Molecules  

NASA Astrophysics Data System (ADS)

The strain field distribution at the surface of a multilayer structure with disklike SiGe nanomounds formed by heteroepitaxy is exploited to arrange the symmetric quantum dot molecules typically consisting of four elongated quantum dots ordered along the [010] and [100] directions. The morphological transition from fourfold quantum dot molecules to continuous fortresslike quantum rings with an increasing amount of deposited Ge is revealed. We examine key mechanisms underlying the formation of lateral quantum dot molecules by using scanning tunneling microscopy and numerical calculations of the strain energy distribution on the top of disklike SiGe nanomounds. Experimental data are well described by a simple thermodynamic model based on the accurate evaluation of the strain dependent part of the surface chemical potential. The spatial arrangement of quantum dots inside molecules is attributed to the effect of elastic property anisotropy.

Zinovyev, V. A.; Dvurechenskii, A. V.; Kuchinskaya, P. A.; Armbrister, V. A.

2013-12-01

12

Exciton scattering on symmetric branching centers in conjugated molecules.  

PubMed

The capability of the exciton scattering approach, an efficient methodology for excited states in branched conjugated molecules, is extended to include symmetric triple and quadruple joints that connect linear segments on the basis of the phenylacetylene backbone. The obtained scattering matrices that characterize these vertices are used in application of our approach to several test structures, where we find excellent agreement with the transition energies computed by the reference quantum chemistry. We introduce topological charges, associated with the scattering matrices, which help to formulate useful relations between the number of excitations in the exciton band and the number of repeat units. The obtained features of the scattering phases are analyzed in terms of the observed excited state electronic structure. PMID:21194223

Li, Hao; Wu, Chao; Malinin, Sergey V; Tretiak, Sergei; Chernyak, Vladimir Y

2011-05-12

13

Using Fixed-Node Diffusion Monte Carlo to Probe Rotation-Vibration Coupling in Highly Fluxional Asymmetric Top Molecules  

NASA Astrophysics Data System (ADS)

Our group has developed a fixed-node Diffusion Monte Carlo (DMC) methodology that can be used to describe rotationally excited states of highly fluxional symmetric top molecules. This technique has been thoroughly benchmarked using rotationally excited states of H_3^+, H_3O^+, and NH_3 with J?12. Here, we report a recently developed extension of this methodology to asymmetric top molecules which undergo large amplitude, zero-point vibrational motion. The nodal surfaces used in the fixed-node DMC calculations are obtained from rigid-rotor wave functions calculated using the system's ground state vibrationally averaged rotational constants. The algorithms used to evaluate node crossing and re-crossing are generalized to account for the pronounced curvature exhibited by the nodal surfaces of asymmetric top molecules with ? ? 0 due to the strong mixing of two or more symmetric top basis functions. Finally, the insight that can be obtained from these calculations into the nature and strength of the vibration-rotation coupling present in highly fluxional asymmetric top molecules will be briefly discussed and further elaborated on in the following talk. A. S. Petit and A. B. McCoy, J. Phys. Chem. A 113, 12706 (2009). A. S. Petit, B. A. Wellen, and A. B. McCoy, J. Chem. Phys. 136, 074101 (2012).

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

2012-06-01

14

Strong photon antibunching of symmetric and antisymmetric modes in weakly nonlinear photonic molecules  

NASA Astrophysics Data System (ADS)

We study the photon statistics of symmetric and antisymmetric modes in a photonic molecule consisting of two linearly coupled nonlinear cavity modes. Our calculations show that strong photon antibunching of both symmetric and antisymmetric modes can be obtained even when the nonlinearity in the photonic molecule is weak. The strong antibunching effect results from the destructive interference between different paths for two-photon excitation. Moreover, we find that the optimal frequency detunings for strong photon antibunching in the symmetric and antisymmetric modes are linearly dependent on the coupling strength between the cavity modes in the photonic molecule. This implies that the photonic molecules can be used to generate tunable single-photon sources by tuning the values of the coupling strength between the cavity modes with weak nonlinearity.

Xu, Xun-Wei; Li, Yong

2014-09-01

15

Inducing changes in the bond length of diatomic molecules by time-symmetric chirped pulses  

SciTech Connect

We show numerically that it is possible to change the structure of a simple molecule, that is, a diatomic molecule, where the bond length is modified at a precise timing with symmetrically chirped laser pulses. In the adiabatic regime, the process is fully time reversible, making it possible to design slow vibrations with large bond elongations. The scheme relies on the preparation of a separable state of both nuclear and electronic degrees of freedom with predominant amplitude on the dissociative (antibonding) electronic wave function. Shorter laser pulses can be used to dynamically induce larger bond elongations, preparing a highly excited vibrational wave packet in the ground potential as the laser is switched off.

Chang, Bo Y.; Shin, Seokmin; Sola, Ignacio R. [School of Chemistry (BK21), Seoul National University, Seoul 151-747 (Korea, Republic of); Departamento de Quimica Fisica, Universidad Complutense, E-28040 Madrid (Spain)

2010-12-15

16

Ionization of a water molecule by electron impact in coplanar symmetric and asymmetric geometries  

NASA Astrophysics Data System (ADS)

Our previous analytical formalism developed in the second Born approximation is completed by the exchange effect between the free outgoing electrons. This formalism is used to predict the triple differential cross sections for the single ionization of a water molecule by electron impact. The results are compared to previous experimental and theoretical findings given in coplanar symmetric and asymmetric geometries. Good agreement with the experiment is given by the present formalism. The discussion of the present results can be used to improve the different models used to study the ionization of a water molecule by charged particles.

Sahlaoui, Mohammed; Bouamoud, Mammar; Lasri, Boumediene; Dogan, Mevlüt

2013-06-01

17

Perturbations of the dominant approximation in spherical-top molecules  

NASA Astrophysics Data System (ADS)

The tensor perturbations in the rotational fine structure of spherical-top fundamental vibrational bands are analyzed in detail. The shift of a fine-structure sublevel ( v = 1, J, R, p) is the result of fourth-rank tensor interactions with sublevels belonging to other manifolds with the same J but different R', due to the matrix elements < v = 1, J, R, p| H| v = 1, J, R', p'>, which are proportional to the symmetry-adapted vector-coupling coefficients FA1 pp' (4, R, R') of Moret-Bailly. Sum rules are derived for general binary products of these matrix elements, and for particular linear combinations of ternary and binary products arising in perturbation theory. These lead to analytical expressions for the second- and third-order perturbation corrections to the transition wavenumbers. To this order of approximation the formulas are expressed in terms of scalar functions of J and R, diagonalF(4) and F(6) tensor functions, and the g˜ function of Ozier. For the third-order formulas, many tedious algebraic manipulations were avoided by computing the sums numerically for each value of ( R - J) and a range of values of R, and then obtaining the algebraic form of the coefficients, which are known to be rational functions of R, by generalization from the numerical results. This technique will be useful in other higher-order perturbation calculations. The cluster properties of the F(4) and F(6) functions in high- J manifolds explain the major qualitative features of the behavior of the perturbations. In the high- R limit, 3 j coefficients give the positions of the clusters. Explicit expressions for these coefficients give a partial check of the present general algebraic expressions. The formalism is tested for the ?3 and ?4 bands of the SiF 4 molecule, using as data energy levels computed from the known spectroscopic parameters. Because of the different ? Coriolis coupling constants, these two cases differ markedly in the rate of convergence of the perturbation expansions. For each band, wavenumber data generated by computer diagonalization of the Hecht Hamiltonian operator are fitted using the perturbation formulas, and the results demonstrate the accuracy, reliability, and limitations in the use of this approximate treatment for the fitting of spectral lines.

Krohn, Burton J.; Watson, James K. G.

1988-06-01

18

APS/123-QED Field-free molecular alignment of asymmetric top molecules using elliptically  

E-print Network

], or Coulomb explosion. Aligning or orient- ing molecules is interesting for study of stereodynamic effects of a reaction can be enhanced by manipulating the relative orientation of reagents. One reaction channel can polarized lasers have been used to align the strongest polarizability axis of asymmetric top molecules right

Paris-Sud XI, Université de

19

Charge symmetric dissociation of doubly ionized N2 and CO molecules  

NASA Astrophysics Data System (ADS)

We report a comparative study of the features in dissociative double ionization by high energy electron impact of N2 and CO molecules. The ratio of cross-section of charge symmetric dissociative ionization to non-dissociative ionization (CSD-to-ND ratio) and the kinetic energy release (KER) spectra of dissociation are experimentally measured and carefully corrected for various ion transmission losses and detector inefficiencies. Given that the double ionization cross sections of these iso-electronic diatomics are very similar, the large difference in the CSD-to-ND ratios must be attributable to the differences in the evolution dynamics of the dications. To understand these differences, potential energy curves (PECs) of dications have been computed using multi-reference configuration interaction method. The Franck-Condon factors and tunneling life times of vibrational levels of dications have also been computed. While the KER spectrum of N_2^{++} can be readily explained by considering dissociation via repulsive states and tunneling of meta-stable states, indirect dissociation processes such as predissociation and autoionization have to be taken into account to understand the major features of the KER spectrum of CO++. Direct and indirect processes identified on the basis of the PECs and experimental KER spectra also provide insights into the differences in the CSD-to-ND ratios.

Pandey, A.; Bapat, B.; Shamasundar, K. R.

2014-01-01

20

The quadrupole moments of spherical-top molecules in orbitally degenerate states  

NASA Astrophysics Data System (ADS)

It is shown that in gases of spherical-top molecules with orbitally degenerate ground electronic terms the orientational mechanism contributes to the generation of birefringence in the presence of a non-uniform electric field. The orientation of molecules by such a field results from the existence of the non-zero quadrupole moments which are available in the molecules under consideration. The contribution to the optical anisotropy arising from the degeneracy has a complicated temperature dependence. At low temperatures, when the ground vibronic state is mainly populated, this contribution is a linear function of inverse temperature as in the case of anisotropic molecules with the symmetry lower than cubic. At intermediate and high temperatures the dependence of the optical anisotropy on T is sufficiently determined by the Jahn-Teller effect taking place when the electronic state has orbital degeneracy. Numerical estimation shows that the effective magnitudes of quadrupole moments of some spherical-top molecules, for example VCl4, ReF6 and IrF6 (G3/2 ground electronic term), are comparable to the quadrupole moments of the diatomic molecules.

Ogurtsov, I. Ya.; Ostrovski, V. L.

21

First-order hyperpolarizabilities of octupolar aromatic molecules: symmetrically substituted triazines  

NASA Astrophysics Data System (ADS)

The first hyperpolarizabilities of some symmetrically substituted triazines have been measured and compared with those of the corresponding symmetrically substituted benzenes. The octupolar triazines have higher quadratic polarizabilities than the corresponding octupolar benzenes. The triazine ring seems to be a better central acceptor than the benzene ring, but if it acts as a donor as in sym-triphenyl triazine, the nonlinearity improves further.

Ray, Paresh Chandra; Das, Puspendu Kumar

1995-09-01

22

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

NASA Astrophysics Data System (ADS)

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.

Chandra, Suresh

23

Computational studies of x-ray scattering from three-dimensionally-aligned asymmetric-top molecules.  

SciTech Connect

We theoretically and numerically analyze x-ray scattering from asymmetric-top molecules three-dimensionally aligned using elliptically polarized laser light. A rigid-rotor model is assumed. The principal axes of the polarizability tensor are assumed to coincide with the principal axes of the moment of inertia tensor. Several symmetries in the Hamiltonian are identified and exploited to enhance the efficiency of solving the time-dependent Schroedinger equation for each rotational state initially populated in a thermal ensemble. Using a phase-retrieval algorithm, the feasibility of structure reconstruction from a quasiadiabatically aligned sample is illustrated for the organic molecule naphthalene. The spatial resolution achievable strongly depends on the laser parameters, the initial rotational temperature, and the x-ray pulse duration. We demonstrate that for a laser peak intensity of 5 TW/cm{sup 2}, a laser pulse duration of 100 ps, a rotational temperature of 10 mK, and an x-ray pulse duration of 1 ps, the molecular structure may be probed at a resolution of 1 {angstrom}.

Pabst, S.; Ho, P.; Santra, R. (Chemical Sciences and Engineering Division); (Univ. Erlangen-Nuremberg); (Univ. of Chicago)

2010-01-01

24

The solvent effect in an axially symmetric Fe(III)4 single-molecule magnet.  

PubMed

A pair of enantiopure Fe(III)4 SMMs with axial symmetry was synthesized and characterized by magnetization and high-frequency electron paramagnetic resonance methods. The results reveal that the axial symmetry of the structure is broken by the interaction of Fe(III)4 with the disordered solvent molecules. PMID:25332152

Zhu, Yuan-Yuan; Yin, Ting-Ting; Jiang, Shang-Da; Barra, Anne-Laure; Wernsdorfer, Wolfgang; Neugebauer, Petr; Marx, Raphael; Dörfel, María; Wang, Bing-Wu; Wu, Zong-Quan; Slageren, Joris van; Gao, Song

2014-11-01

25

Microwave spectrum of two top molecules in the excited states dimethyl ether, dimethyl sulfide, and dimethyl silane  

NASA Astrophysics Data System (ADS)

Microwave spectra of dimethyl ether, dimethyl sulfide, and dimethyl silane in the torsionally excited states have been measured. The methyl internal rotations of these molecules were analyzed from the observed multiplets and from the reported multiplets of transitions. The method developed for ethyl silane in the previous paper was extended to equivalent two top molecules. For equivalent two top molecules, apparent barriers of methyl internal rotations obtained from the experiments were corrected by the kinetic and potential cross terms. They are V3=2645.8±10.0, 2632.4 ± 42.9, 2146.0 ± 13.8, 1651.5 ± 10.1, 1648.0 ± 13.7, and 1649.9 ± 11.8 cal/mol for (CH 3) 2O, (CD 3) 2O, (CH 3) 2S, (CH 3) 2SiH 2, (CH 3) 2SiD 2, and (CH 3) 2SiHD, respectively. The potential cross terms, V12(1-cos3 ?1)(1-cos3 ?2) terms are negligible for the three molecules, while V'12sin3 ?1sin3 ?2 terms are also very close to zero except those for (CH 3) 2O and (CD 3) 2O which are small but not negligible ( V'12=-124.4,-158.0 cal/mol). The investigations were extended to those of non-equivalent two top species and the corrected barriers of the methyl tops, V3, are obtained to be 2615.6 ± 8.6 and 2155.0 ± 15.2 cal/mol for CH 3OCD 3 and CH 3SCD 3. The corrected barrier, V3(CD 3) of CH 3OCD 3, is obtained to be 2634.4 ± 7.1 cal/mol, while that of CH 3SCD 3 cannot be solved due to the lack of the data available.

Niide, Yuzuru; Hayashi, Michiro

2004-02-01

26

Evidence for Orbital-Specific Electron Transfer to Oriented Haloform Molecules  

E-print Network

molecules have been oriented by "brute force" techniques,14,15 and a number of small symmetric tops have for their intrinsic interest. Whereas most small molecules are near-prolate tops18 which are difficult to spin aboutEvidence for Orbital-Specific Electron Transfer to Oriented Haloform Molecules Beike Jia, Jonathan

Brooks, Philip R.

27

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

SciTech Connect

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.

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

28

Molecular structure determination from x-ray scattering patterns of laser-aligned symmetric-top molecules  

E-print Network

are calculated at an x-ray photon energy of 20 keV to probe molecular structure at angstrom-scale resolution. We pattern to be treated as a hologram. Using this approach, the azimuthal projection of the molecular

Saldin, Dilano

29

Nonequilibrium rotational distribution function for D 2 O molecules in a rarefied supersonic jet  

Microsoft Academic Search

Rotational relaxation of the D20 molecule in a rarefied supersonic argon jet was investigated in the present work. This was done earlier for diatomic, polyatomic, and linear molecules and molecules of the symmetric-top type [4, 5], while for molecules of the asymmetrictop type it is being done for the first time. The purpose of the work was to investigate the

S. S. Bakastov; V. K. Konyukhov; V. I. Tikhonov

1985-01-01

30

Controlling the rotation of asymmetric top molecules by the combination of a long and a short laser pulse  

E-print Network

to a molecule 3,4-dibromothiophene , with significantly different inertia and polarizability tensors. Finally and molecular assembly and to new control opportunities 15 . Extensions of alignment to orientation 17

Seideman, Tamar

31

Quantum decoherence in the rotation of small molecules  

E-print Network

The dynamics of non-polar diatomic molecules interacting with a far-detuned narrow-band laser field, that only may drive rotational transitions, is studied. The rotation of the molecule is considered both classically and quantum mechanically, providing links to features known from the heavy symmetric top. In particular, quantum decoherence in the molecular rotation, being induced by spontaneous Raman processes, is addressed. It is shown how this decoherence modifies the rotational dynamics in phase space.

A. Adelswaerd; S. Wallentowitz

2004-01-26

32

Closed-loop phase equilibria of a symmetrical associating mixture of square-well molecules examined by Gibbs ensemble Monte Carlo simulation  

Microsoft Academic Search

A closed loop of liquid-liquid immiscibility for a simple model binary symmetrical mixture of square-well monomers with a single short-ranged interaction site has been recently observed using the Gibbs ensemble Monte Carlo technique [L. A. Davies, G. Jackson, and L. F. Rull, Phys. Rev. Lett. 82, 5285 (1999)]. This model system has unfavorable mean-field interactions between unlike components which leads

Lowri A. Davies; George Jackson; Luis F. Rull

2000-01-01

33

Closed-loop phase equilibria of a symmetrical associating mixture of square-well molecules examined by Gibbs ensemble Monte Carlo simulation  

NASA Astrophysics Data System (ADS)

A closed loop of liquid-liquid immiscibility for a simple model binary symmetrical mixture of square-well monomers with a single short-ranged interaction site has been recently observed using the Gibbs ensemble Monte Carlo technique [L. A. Davies, G. Jackson, and L. F. Rull, Phys. Rev. Lett. 82, 5285 (1999)]. This model system has unfavorable mean-field interactions between unlike components which leads to phase separation at intermediate temperatures; the addition of a directional bonding site leads to association and miscibilty of the system at low temperatures. In this work we present a detailed study of the effect of a variation in pressure and of the strength of the bonding interaction on the phase equilibria of such a model system by Gibbs ensemble simulation. The phase diagram is dominated by regions of liquid-liquid immiscibility which are bounded at high temperatures by an upper critical solution temperature and by a lower critical solution temperature (LCST) for specific values of the pressure and association strength. This closed-loop region is seen to increase in size as the pressure of the system is increased. For weak bonding interaction strengths the system does not possess a LCST and is seen to exhibit regions of two-phase vapor-liquid coexistence which are separated from the region of liquid-liquid immiscibility by a three-phase line. The phase equilibria of the same model system is also determined using the statistical associating fluid theory as adapted for potentials of variable range; the theory provides a good description of the closed-loop immiscibility and other features of the phase diagram.

Davies, Lowri A.; Jackson, George; Rull, Luis F.

2000-03-01

34

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

NASA Technical Reports Server (NTRS)

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.

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

1974-01-01

35

Affine Stanley symmetric functions  

Microsoft Academic Search

We define a new family of symmetric functions which are affine analogues of Stanley symmetric functions. We establish basic properties of these functions including symmetry, dominance and conjugation. We conjecture certain positivity properties in terms of a subfamily of symmetric functions called affine Schur functions. As applications, we show how affine Stanley symmetric functions generalise the (dual of the) $k$-Schur

Thomas Lam

2005-01-01

36

Symmetric Novikov superalgebras  

SciTech Connect

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.

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

37

Left-symmetric algebroids  

E-print Network

In this paper, we introduce a notion of a left-symmetric algebroid, which is a generalization of a left-symmetric algebra from a vector space to a vector bundle. The left multiplication gives rise to a representation of the corresponding sub-adjacent Lie algebroid. We construct left-symmetric algebroids from $\\mathcal O$-operators on Lie algebroids. We study phase spaces of Lie algebroids in terms of left-symmetric algebroids. Representations of left-symmetric algebroids are studied in detail. At last, we study deformations of left-symmetric algebroids, which could be controlled by the second cohomology class in the deformation cohomology.

Jiefeng Liu; Yunhe Sheng; Chengming Bai; Zhiqi Chen

2013-12-23

38

Precision Electroweak Constraints on Top-Color Assisted Technicolor  

E-print Network

) interaction. He argued that the extreme fine-tuning that was required in pure top-condensate models can-symmetric top-color interaction and an additional (possibly weak, but probably strong) isospin-breaking U(1 on , they found that either the effective top quark coupling or the top-color coupling must be tuned to 1

Terning, John

39

Symmetrical Bi-Aromatics  

Microsoft Academic Search

RECORDED instances of the preparation of symmetrically substituted bithienyls appear only scattered in the literature1. Furthermore, no work has been published concerning the symmetrically substituted 3,3'-bithienyls.

Louis J. Owen; F. F. Nord

1951-01-01

40

Beam broadening of polar molecules and clusters in deflection experiments.  

PubMed

A beam of rotating dipolar particles (molecules or clusters) will broaden when passed through an electric or magnetic field gradient region. This broadening, which is a common experimental observable, can be expressed in terms of the variance of the distribution of the resulting polarization orientation (the direction cosine). Here, the broadening for symmetric-top and linear rotors is discussed. These two types of rotors have qualitatively different low-field orientation distribution functions, but behave similarly in a strong field. While analytical expressions for the polarization variance can be derived from first-order perturbation theory, for experimental guidance it is important to identify the applicability and limitations of these expressions, and the general dependence of the broadening on the experimental parameters. For this purpose, the analytical results are compared with the full diagonalization of the rotational Stark-effect matrices. Conveniently for experimental estimations, it is found that for symmetric tops, the dependence of the broadening parameter on the rotational constant, the axial ratio, and the field strength remains similar to the analytical expression even outside of the perturbative regime. Also, it is observed that the shape envelope, the centroid, and the width of the orientation distribution function for a symmetric top are quite insensitive to the value of its rotational constant (except at low rotational temperatures). PMID:22239775

Bulthuis, J; Kresin, V V

2012-01-01

41

Ejs Lagrange Top Model  

NSDL National Science Digital Library

The Ejs Lagrange Top model displays the motion of a heavy symmetric top under the effect of gravity. The top has an initial angular speed that provides the precessional, nutational, and rotational speeds. The ratio of Lz to Lâ can be set via slider and the initial angular position and angular speeds can be changed via textboxes. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Lagrange Top model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_rigid_bodies_Lagrange.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for rigid body dynamics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-08-18

42

Spherically symmetric dynamical horizons  

E-print Network

We determine sufficient and necessary conditions for a spherically symmetric initial data set to satisfy the dynamical horizon conditions in the spacetime development. The constraint equations reduce to a single second order linear master equation, which leads to a systematic construction of all spherically symmetric dynamical horizons (SSDH) satisfying certain boundedness conditions. We also find necessary and sufficient conditions for a given spherically symmetric spacetime to contain a SSDH.

Robert Bartnik; Jim Isenberg

2005-12-15

43

Z scan using circularly symmetric beams  

Microsoft Academic Search

We report general characteristics of on-axis Z-scan transmittance for arbitrary circularly symmetric beams. Some experimental results are presented for a nearly top-hat-shaped beam and for a trimmed Airy beam whose electric field profile is the central portion of an Airy function inside its first zero. The sensitivity of Z-scan method with a trimmed Airy beam for measuring an induced index-of-refraction

Bum Ku Rhee; Jin Seob Byun; E. W. Van Stryland

1996-01-01

44

Pizza Toppings  

NSDL National Science Digital Library

In this video segment from Cyberchase, Bianca wants to pick up a pizza to share with her two friends. Each of the three friends has topping preferences, so Bianca hopes to create a pizza that will satisfy all of their requests. In order to organize the preferences, Bianca draws a Venn Diagram and then arranges the pizza toppings according to the diagram. This video is also featured as part of the lesson, "Building Venn Diagrams" which is cataloged separately. Teaching tips and a transcript of the dialogue are included.

2002-01-01

45

PT-Symmetric Acoustics  

NASA Astrophysics Data System (ADS)

We introduce here the concept of acoustic parity-time (PT) symmetry and demonstrate the extraordinary scattering characteristics of the acoustic PT medium. On the basis of exact calculations, we show how an acoustic PT-symmetric medium can become unidirectionally transparent at given frequencies. Combining such a PT-symmetric medium with transformation acoustics, we design two-dimensional symmetric acoustic cloaks that are unidirectionally invisible in a prescribed direction. Our results open new possibilities for designing functional acoustic devices with directional responses.

Zhu, Xuefeng; Ramezani, Hamidreza; Shi, Chengzhi; Zhu, Jie; Zhang, Xiang

2014-07-01

46

Architectural Tops  

ERIC Educational Resources Information Center

The development of the skyscraper is an American story that combines architectural history, economic power, and technological achievement. Each city in the United States can be identified by the profile of its buildings. The design of the tops of skyscrapers was the inspiration for the students in the author's high-school ceramic class to develop…

Mahoney, Ellen

2010-01-01

47

Creating a Symmetrical Design  

NSDL National Science Digital Library

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.

Service, National S.

2009-04-24

48

The coexistence of molecules having different structures in organic crystals  

Microsoft Academic Search

A comparison of the structures of symmetrically independent molecules coexisting in organic crystals has been carried out on the basis of the statistical treatment of x-ray diffraction data. The analysis of 330 crystal structures containing such molecules showed that 20% of the crystals contain molecules with different Iconformations (the phenomenon of contact conformerism); in 80% of cases the symmetrically independent

P. M. Zorkii; A. E. Razumaeva

1979-01-01

49

Braids, shuffles and symmetrizers  

NASA Astrophysics Data System (ADS)

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.

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

2009-07-01

50

Symmetric factorization Riccati equations  

E-print Network

Symmetric factorization Riccati equations and Bezoutians collaboration with I. Karelin and L. Lerer() - C(I - A)-1B is analytic over the whole complex plane, and · (A, B, C) is minimal. #12;Special case�-invariant subspace is of the form M� = Im X I , where X = X satisfies the algebraic Riccati equation XCCX + X(A - BC

51

Ultrafast Electron Diffraction of Laser-Aligned CF3I Molecules  

NASA Astrophysics Data System (ADS)

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.

Hensley, Christopher; Yang, Jie; Centurion, Martin

2012-06-01

52

Symmetric Controller Design for Symmetric Plant Using Matrix Inequality Conditions  

Microsoft Academic Search

For symmetric systems, the useage of symmetric controllers is known to be effective. The existence conditions of the controller have been shown in several studies. They require the symmetry of the plant as well as the control specifications. This paper describes the condition by matrix inequalities and relaxes it to be applicable to the case of non-symmetric sepcifications for the

Tomoyuki Nagashio; Takashi Kida

2005-01-01

53

Symmetric modular torsatron  

DOEpatents

A fusion reactor device is provided in which the magnetic fields for plasma confinement in a toroidal configuration is produced by a plurality of symmetrical modular coils arranged to form a symmetric modular torsatron referred to as a symmotron. Each of the identical modular coils is helically deformed and comprise one field period of the torsatron. Helical segments of each coil are connected by means of toroidally directed windbacks which may also provide part of the vertical field required for positioning the plasma. The stray fields of the windback segments may be compensated by toroidal coils. A variety of magnetic confinement flux surface configurations may be produced by proper modulation of the winding pitch of the helical segments of the coils, as in a conventional torsatron, winding the helix on a noncircular cross section and varying the poloidal and radial location of the windbacks and the compensating toroidal ring coils.

Rome, J.A.; Harris, J.H.

1984-01-01

54

Symmetrical Bi-Aromatics  

Microsoft Academic Search

PREVIOUSLY reported work1 from this laboratory indicated the feasibility of condensing 2-halo-3-thenoic acids to form symmetrically substituted 2,2'-bithienyls. This provided the experimental basis for the continuation of our studies in the field of mixed bi-aromatics, wherein it was shown2 that an unsymmetrically substituted alpha-phenylthiophene actually exists in two stereoisomeric forms due to restricted rotation. In view of this fact, the

George N. Jean; Louis J. Owen; F. F. Nord

1952-01-01

55

Symmetrical reconfiguration of tensegrity structures  

Microsoft Academic Search

In this article we first present a mathematical model which describes the nonlinear dynamics of tensegrity structures. For certain tensegrity structures a particular class of motions, coined symmetrical motions, is defined. The corresponding equations of motion are derived and the conditions under which symmetrical motions occur are established. Reconfiguration procedures through symmetrical motions are proposed and examples are given.

Cornel Sultan; Martin Corless; Robert E. Skelton

2002-01-01

56

Plane Symmetric, Cylindrically Symmetric and Spherically Symmetric Black Solutions of Einstein Field Equations  

E-print Network

In this paper we present Plane symmetric, Cylindrically Symmetric and Spherically Symmetric Black hole or Vacuum solutions of Einstein Field Equations(EFEs). Some of these solutions are new which we have not seen in the literature. This calculation will help us in understanding the gravitational wave and gravitational wave spacetimes.

Farhad Ali

2014-10-19

57

Microwave Lens for Polar Molecules  

E-print Network

We here report on the implementation of a microwave lens for neutral polar molecules suitable to focus molecules both in low-field-seeking and in high-field-seeking states. By using the TE_11m modes of a 12 cm long cylindrically symmetric microwave resonator, Stark-decelerated ammonia molecules are transversally confined. We investigate the focusing properties of this microwave lens as a function of the molecules' velocity, the detuning of the microwave frequency from the molecular resonance frequency, and the microwave power. Such a microwave lens can be seen as a first important step towards further microwave devices, such as decelerators and traps.

Odashima, Hitoshi; Enomoto, Katsunari; Schnell, Melanie; Meijer, Gerard

2010-01-01

58

Modifications to Axially Symmetric Simulations Using New DSMC (2007) Algorithms  

NASA Technical Reports Server (NTRS)

Several modifications aimed at improving physical accuracy are proposed for solving axially symmetric problems building on the DSMC (2007) algorithms introduced by Bird. Originally developed to solve nonequilibrium, rarefied flows, the DSMC method is now regularly used to solve complex problems over a wide range of Knudsen numbers. These new algorithms include features such as nearest neighbor collisions excluding the previous collision partners, separate collision and sampling cells, automatically adaptive variable time steps, a modified no-time counter procedure for collisions, and discontinuous and event-driven physical processes. Axially symmetric solutions require radial weighting for the simulated molecules since the molecules near the axis represent fewer real molecules than those farther away from the axis due to the difference in volume of the cells. In the present methodology, these radial weighting factors are continuous, linear functions that vary with the radial position of each simulated molecule. It is shown that how one defines the number of tentative collisions greatly influences the mean collision time near the axis. The method by which the grid is treated for axially symmetric problems also plays an important role near the axis, especially for scalar pressure. A new method to treat how the molecules are traced through the grid is proposed to alleviate the decrease in scalar pressure at the axis near the surface. Also, a modification to the duplication buffer is proposed to vary the duplicated molecular velocities while retaining the molecular kinetic energy and axially symmetric nature of the problem.

Liechty, Derek S.

2008-01-01

59

Tops and Writhing DNA  

E-print Network

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.

Joseph Samuel; Supurna Sinha

2010-11-30

60

Back to Top Back to Top  

E-print Network

Back to Top Back to Top Printer Friendly Version BERKELEY SUMMER SESSIONS The Political Philosophy. Carson, Clayborne (ed.)., The Autobiography of Martin Luther King, Jr. New York Intellectual Properties

Walker, Matthew P.

61

Symmetrization for redundant channels  

NASA Technical Reports Server (NTRS)

A plurality of redundant channels in a system each contain a global image of all the configuration data bases in each of the channels in the system. Each global image is updated periodically from each of the other channels via cross channel data links. The global images of the local configuration data bases in each channel are separately symmetrized using a voting process to generate a system signal configuration data base which is not written into by any other routine and is available for indicating the status of the system within each channel. Equalization may be imposed on a suspect signal and a number of chances for that signal to heal itself are provided before excluding it from future votes. Reconfiguration is accomplished upon detecting a channel which is deemed invalid. A reset function is provided which permits an externally generated reset signal to permit a previously excluded channel to be reincluded within the system. The updating of global images and/or the symmetrization process may be accomplished at substantially the same time within a synchronized time frame common to all channels.

Tulplue, Bhalchandra R. (Inventor); Collins, Robert E. (Inventor)

1988-01-01

62

Optimal symmetric flight studies  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

63

Novel Identification of Symmetric and Anti-Symmetric Quantum Functions  

E-print Network

Procedures are given below to construct symmetric and anti-symmetric quantum functions. If hidden in an oracle, such functions can be identified exactly, without iterative interrogation. This is another example of quantum search. The resulting positive (or negative) functions also serve to uniquely reorganize a superposition of states to give a basis state for testing purposes.

John Robert Burger

2003-08-28

64

Internal Coordinate Formulation for Vibration-Rotation Energies of Polyatomic Molecules  

PubMed

The theory of vibration-rotation interactions in polyatomic molecules using curvilinear internal coordinates for the vibrational degrees of freedom is extended to the situation where the initial molecular axis system is not the principal axis system of the equilibrium configuration. For this new situation, the transformation coefficient rhoit is derived as well as the vibrational coefficients (G-1tt')0. This new transformation may not be useful nor necessary when all of the internal motions are of small amplitude. However, in the case of vibration-rotation-internal rotation interactions, the new transformation is helpful when the internal rotor is a symmetric top and necessary when the internal rotor is an asymmetric top. Copyright 1998 Academic Press. Copyright 1998Academic Press PMID:9473436

Quade

1998-02-01

65

Mighty Molecules  

NSDL National Science Digital Library

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.

Little, Carlyn; Lahart, David; Meyers, Ted; Weisblat, Brooks

1997-01-01

66

Partial Wave Theory of Diatomic Molecules. II  

Microsoft Academic Search

The method of expanding the wavefunction of diatomic molecules in a series of orbital angular momentum eigenfunctions (partial waves) is extended to two-electron homonuclear molecules. The angular momentum is a function of the Euler angles only; a symmetric choice of these angles is used which greatly facilitates the description of the exchange character of the wavefunction. As a result, explicit

A. Temkin; A. K. Bhatia

1965-01-01

67

Top physics at CDF  

SciTech Connect

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.

Julia Thom

2004-06-24

68

Flavor Changing Neutral Currents and Left-Right Symmetric model  

E-print Network

In the present work we consider including the Flavor Changing Neutral Currents (FCNCs) in Left-Right Symmetric model. Within this model a simulation calculation are made of the decay width of Z' LR boson, the production cross section of the top quark and the top quark pair production cross section. The events were simulated according to the extension of Standard Model (SM) and the Left-Right symmetry Model (LRSM) based on the gauge symmetry group SU(3)C SU(2)L SU(2)R U(1)B-L. The LRSM model exhibits signatures of new physics Beyond the Standard Model (BSM) at the hadrons colliders.

H. M. M. Mansour; N. Bakheet

2014-09-28

69

Flavor Changing Neutral Currents and Left-Right Symmetric model  

E-print Network

In the present work we consider including the Flavor Changing Neutral Currents (FCNCs) in Left-Right Symmetric model. Within this model a simulation calculation are made of the decay width of Z' LR boson, the production cross section of the top quark and the top quark pair production cross section. The events were simulated according to the extension of Standard Model (SM) and the Left-Right symmetry Model (LRSM) based on the gauge symmetry group SU(3)C SU(2)L SU(2)R U(1)B-L. The LRSM model exhibits signatures of new physics Beyond the Standard Model (BSM) at the hadrons colliders.

Mansour, H M M

2014-01-01

70

Top Properties at ATLAS  

E-print Network

Properties of the top quark are measured with the ATLAS detector using LHC proton-proton collisions data. Measurements of the top-quark mass and polarisation, as well as of the polarization of W bosons in top quark decays to probe the Wtb-vertex are presented. In addition, measurements of the spin correlation between top and anti-top quarks as well as of the top-quark charge asymmetry, which constitute important tests of QCD and are sensitive to new physics, are discussed.

Sandbach, Ruth Laura; The ATLAS collaboration

2014-01-01

71

Symmetric States in Quantum Geometry  

Microsoft Academic Search

Symmetric states are defined in the kinematical sector of loop quantum\\u000agravity and applied to spherical symmetry and homogeneity. Consequences for the\\u000aphysics of black holes and cosmology are discussed.

M. Bojowaldand; H. A. Kastrup

2001-01-01

72

Molecule nanoweaver  

SciTech Connect

A method, apparatus, and system for constructing uniform macroscopic films with tailored geometric assemblies of molecules on the nanometer scale. The method, apparatus, and system include providing starting molecules of selected character, applying one or more force fields to the molecules to cause them to order and condense with NMR spectra and images being used to monitor progress in creating the desired geometrical assembly and functionality of molecules that comprise the films.

Gerald, II; Rex E. (Brookfield, IL); Klingler, Robert J. (Glenview, IL); Rathke, Jerome W. (Homer Glen, IL); Diaz, Rocio (Chicago, IL); Vukovic, Lela (Westchester, IL)

2009-03-10

73

Cylindrically symmetric electrohydrodynamic patterning.  

PubMed

Cylindrically symmetric structures such as concentric rings and rosettes arise out of thin polymeric films subjected to strong electric fields. Experiments that formed concentric rings and theory capable of explaining these and other cylindrical structures are presented. These rings represent an additional member of a class of structures, including pillars and holes, formed by electrohydrodynamic patterning of thin films, occasionally referred to as lithographically induced self-assembly. Fabrication of a set of concentric rings begins by spin coating a thin poly(methyl methacrylate) film onto a silicon wafer. A mask is superimposed parallel to the film leaving a similarly thin air gap. Electric fields, acting in opposition to surface tension, destabilize the free interface when raised above the glass transition temperature. Central pillars nucleate under small cylindrical protrusions patterned on the mask. Rings then emerge sequentially, with larger systems having as many as 10 fully formed rings. Ring-to-ring spacings and annular widths, typically on the order of a micron, are approximately constant within a concentric cluster. The formation rate is proportional to the viscosity and, consequently, has the expected Williams-Landel-Ferry dependence on temperature. In light of these developments we have undertaken a linear stability analysis in cylindrical coordinates to describe these rings and ringlike structures. The salient feature of this analysis is the use of perturbations that incorporate their radial dependence in terms of Bessel functions as opposed to the traditional sinusoids of Cartesian coordinates. The theory predicts approximately constant ring-to-ring spacings, constant annular widths, and growth rates that agree with experiment. A secondary instability is observed at higher temperatures, which causes the rings to segment into arcs or pillar arrays. The cylindrical theory may be generalized to describe hexagonal pillar/hole packing, gratings, and rosettes with the first being of particular importance given the ubiquitous observation of hexagonal packing. The perturbation analysis presented here is relevant to any system with cylindrical symmetry, for which the radial dependence can be described in terms of Bessel functions. PMID:15600415

Deshpande, Paru; Pease, Leonard F; Chen, Lei; Chou, Stephen Y; Russel, William B

2004-10-01

74

Cylindrically symmetric electrohydrodynamic patterning  

NASA Astrophysics Data System (ADS)

Cylindrically symmetric structures such as concentric rings and rosettes arise out of thin polymeric films subjected to strong electric fields. Experiments that formed concentric rings and theory capable of explaining these and other cylindrical structures are presented. These rings represent an additional member of a class of structures, including pillars and holes, formed by electrohydrodynamic patterning of thin films, occasionally referred to as lithographically induced self-assembly. Fabrication of a set of concentric rings begins by spin coating a thin poly(methyl methacrylate) film onto a silicon wafer. A mask is superimposed parallel to the film leaving a similarly thin air gap. Electric fields, acting in opposition to surface tension, destabilize the free interface when raised above the glass transition temperature. Central pillars nucleate under small cylindrical protrusions patterned on the mask. Rings then emerge sequentially, with larger systems having as many as 10 fully formed rings. Ring-to-ring spacings and annular widths, typically on the order of a micron, are approximately constant within a concentric cluster. The formation rate is proportional to the viscosity and, consequently, has the expected Williams-Landel-Ferry dependence on temperature. In light of these developments we have undertaken a linear stability analysis in cylindrical coordinates to describe these rings and ringlike structures. The salient feature of this analysis is the use of perturbations that incorporate their radial dependence in terms of Bessel functions as opposed to the traditional sinusoids of Cartesian coordinates. The theory predicts approximately constant ring-to-ring spacings, constant annular widths, and growth rates that agree with experiment. A secondary instability is observed at higher temperatures, which causes the rings to segment into arcs or pillar arrays. The cylindrical theory may be generalized to describe hexagonal pillar/hole packing, gratings, and rosettes with the first being of particular importance given the ubiquitous observation of hexagonal packing. The perturbation analysis presented here is relevant to any system with cylindrical symmetry, for which the radial dependence can be described in terms of Bessel functions.

Deshpande, Paru; Pease, Leonard F., III; Chen, Lei; Chou, Stephen Y.; Russel, William B.

2004-10-01

75

Top quark physics  

SciTech Connect

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.

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

2000-03-24

76

Tinkering with Tops  

NSDL National Science Digital Library

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.

Ieee

2014-05-22

77

Spherical Tippe Tops  

ERIC Educational Resources Information Center

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…

Cross, Rod

2013-01-01

78

Top quark physics  

SciTech Connect

While the top quark was discovered in 1995 at the Fermilab Tevatron, a decade later they still have very little information about the top. As the heaviest particle yet discovered, the top quark is interesting in and of itself, but some speculate that it may play a special role in physics beyond the Standard Model. With Run 2 of the Tevatron well underway, they have the opportunity to study top quark properties with much better sensitivity, and to test whether top quarks behave as predicted by current theories. This article focuses on the basics of top quark physics at the Tevatron, highlighting only a sample of the many recent measurements, as new results are being released monthly, and constantly changing the landscape of our knowledge of top.

Erbacher, Robin D.; /UC, Davis

2005-10-01

79

Marvelous Molecules  

NSDL National Science Digital Library

Presented by the New York Hall of Science, the Marvelous Molecules Web site accompanies its physical museum's exhibit by offering descriptions and additional online activities. The first page "About the Exhibit" shows what is available at the museum and gives interesting facts about molecules. The next page "All About Molecules" explains what a molecule is and gives eight examples (e.g., aspirin and carbon dioxide). The next page called "Marvelous Activities" contains several activities, one of which is the "How Many Molecules Are You?" interactive exercise. Here, users input their weight to see how many molecules their bodies contain and how that compares to other living things. Geared mainly towards kids, the Web site should give all people a fun way to learn.

1969-12-31

80

Molecule matters  

Microsoft Academic Search

Carbon dioxide is a fascinating molecule; its gaseous, liquid, solid and even supercritical fluid states have unique properties\\u000a and applications. The linear triatomic structure of carbon dioxide molecule with two carbon-oxygen double bonds is all too\\u000a familiar. However a whole new world has been opened up by high pressure-high temperature experiments that effected the polymerization\\u000a of this small molecule into

T. P. Radhakrishnan

2006-01-01

81

Top Physics at CDF  

SciTech Connect

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.

Moon, Chang-Seong

2011-06-01

82

Secure Symmetrical Multilevel Diversity Coding  

E-print Network

Secure symmetrical multilevel diversity coding (S-SMDC) is a source coding problem, where a total of L - N discrete memoryless sources (S1,...,S_L-N) are to be encoded by a total of L encoders. This thesis considers a natural generalization of SMDC...

Li, Shuo

2012-07-16

83

The symmetric strong moment problem  

Microsoft Academic Search

Sequences of polynomials that occur as denominators in the two point Paté table for two series expansions are considered in the special case when the series coefficients are solutions of a strong symmetric Stieltjes moment problem. The continued fractions whose convergents generate these polynomials as denominators are presented, together with determinant representations for the polynomials and the continued fraction coefficients.

A. K. Common; J. H. McCabe

1996-01-01

84

Simulation of Symmetrical Induction Machinery  

Microsoft Academic Search

The effectiveness of an analog computer in studying the performance of induction machinery is demonstrated with computer results which show the dynamic behavior of 2-phase and 3-phase machines during balanced and unbalanced operation. The computer simulation for these various modes of operation is conveniently obtained from the equations which describe the symmetrical induction machine in an arbitrary reference frame. Of

P. C. Krause; C. H. Thomas

1965-01-01

85

Marvelous Molecules  

NSDL National Science Digital Library

Presented by the New York Hall of Science, the Marvelous Molecules Web site accompanies its physical museum's exhibit by offering descriptions and additional online activities. The page features section on: the exhibit, activities, molecules and the New York Science homepage. Within the activities page, the site currently features three main lessons focusing on molecules, DNA and infra-red technology. The exhibit page displays pictures and additional information on the learning objectives of the display. The site features contact information for those interesting in more information on the exhibit.

2009-04-30

86

Top-Level Structures  

ERIC Educational Resources Information Center

In this article, the author discusses top-level structure, a form of text structure that would help students improve their reading comprehension. There are four main organizational patterns, or top-level structures, that occur mostly in factual texts: compare/contrast, cause/effect, problem/ solution, and list-like. Authors often use signaling…

Bolton, Faye

2007-01-01

87

Training Top 125  

ERIC Educational Resources Information Center

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…

Training, 2012

2012-01-01

88

Top Quark Condensate Revisited  

Microsoft Academic Search

In the light of recent discovery of a very heavy top quark, we reexamine the top quark condensate model proposed by Miransky, Tanabashi and Yamawaki (MTY) and by Nambu. We first review the original MTY formulation based on the ladder Schwinger-Dyson equation and the Pagels-Stokar formula. It is particularly emphasized that the critical phenomenon gives a simple reason why the

Koichi Yamawaki

1996-01-01

89

The Top Quark  

Microsoft Academic Search

Since the discovery of the bottom quark in 1977, physicists have searched for the top quark, the weak isospin partner of the bottom quark. Indirect evidence and estimates of its mass have been made; however, direct observation eluded scientists until recently. In the spring of 1995, two experiments, CDF and DØ, at Fermi National Accelerator Laboratory showed top-antitop quark pairs

Stephen J. Wimpenny; Brian L. Winer

1996-01-01

90

Modeling Molecules  

NASA Technical Reports Server (NTRS)

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.

2000-01-01

91

Interstellar Molecules  

ERIC Educational Resources Information Center

Radioastronomy reveals that clouds between the stars, once believed to consist of simple atoms, contain molecules as complex as seven atoms and may be the most massive objects in our Galaxy. (Author/DF)

Solomon, Philip M.

1973-01-01

92

Top physics at CDF  

SciTech Connect

We report on top physics results using a 100 pb{sup -1} data sample of p{bar p} collisions at {radical}s = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). We have identified top signals in a variety of decay channels, and used these channels to extract a measurement of the top mass and production cross section. A subset of the data (67 pb{sup -1}) is used to determine M{sub top} = 176 {+-} 8(stat) {+-} 10(syst) and {sigma}(tt) = 7.6 {sub -2.0}{sup +2.4} pb. We present studies of the kinematics of t{bar t} events and extract the first direct measurement of V{sub tb}. Finally, we indicate prospects for future study of top physics at the Tevatron.

Hughes, R.E. [Univ. of Rochester, NY (United States)

1997-01-01

93

Absence of inflation symmetric commensurate states in inflation symmetric networks  

Microsoft Academic Search

In this paper we présent measurements of thé normal-to superconducting phase boundary T_c(H) for three différent networks possessing inflation symmetry. Fluxoid quantization constraints induce thé formation of a lattice of fluxoid quanta for any non-zéro perpendicular magnetic field, and at particular fields, T_c(H) exhibits cusp-like structure indicating that thé lattice is commensurate with thé underlying network geometry. For inflation symmetric

M. A. Itzler; R. Bojko; P. M. Chaikin

1994-01-01

94

PT-symmetric phonon laser.  

PubMed

By exploiting recent developments associated with coupled microcavities, we introduce the concept of the PT-symmetric phonon laser with balanced gain and loss. This is accomplished by introducing gain to one of the microcavities such that it balances the passive loss of the other. In the vicinity of the gain-loss balance, a strong nonlinear relation emerges between the intracavity-photon intensity and the input power. This then leads to a giant enhancement of both optical pressure and mechanical gain, resulting in a highly efficient phonon-lasing action. These results provide a promising approach for manipulating optomechanical systems through PT-symmetric concepts. Potential applications range from enhancing mechanical cooling to designing phonon-laser amplifiers. PMID:25126921

Jing, Hui; Özdemir, S K; Lü, Xin-You; Zhang, Jing; Yang, Lan; Nori, Franco

2014-08-01

95

PT-Symmetric Phonon Laser  

E-print Network

By exploiting recent developments associated with coupled microcavities, we introduce the concept of PT-symmetric phonon laser with balanced gain and loss. This is accomplished by introducing gain to one of the microcavities such that it balances the passive loss of the other. In the vicinity of the gain-loss balance, a strong nonlinear relation emerges between the intracavity photon intensity and the input power. This then leads to a giant enhancement of both optical pressure and mechanical gain, resulting in a highly efficient phonon-lasing action. These results provide a promising approach for manipulating optomechanical systems through PT-symmetric concepts. Potential applications range from enhancing mechanical cooling to designing phonon-laser amplifiers.

H. Jing; Sahin K. Ozdemir; Xin-You Lv; Jing Zhang; Lan Yang; Franco Nori

2014-03-04

96

Top Quark Properties  

SciTech Connect

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.

Peters, Yvonne

2011-12-01

97

Symmetrization, quantum images and measurement  

E-print Network

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.

Shafee, F

2005-01-01

98

Symmetrization, quantum images and measurement  

E-print Network

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.

Fariel Shafee

2005-07-11

99

Spherically symmetric canonical quantum gravity  

E-print Network

Canonical quantization of spherically symmetric space-times is carried out, using real-valued densitized triads and extrinsic curvature components, with specific factor ordering choices. Comparison with previous work [1] 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.

Brahma, Suddhasattwa

2014-01-01

100

Greedy algorithm and symmetric matroids  

Microsoft Academic Search

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.

André Bouchet

1987-01-01

101

Top quark production  

E-print Network

We review the current status of the cross sections measurement of the top-quark at the LHC and at the Tevatron. Total production cross sections, studies using single top quark events and differential $\\rm{t}\\bar{\\rm t}$ cross sections are discussed. The associated production of top quark pairs with photons, Z and W bosons, including $\\rm{t}\\bar{\\rm t}$Z and $\\rm{t}\\bar{\\rm t}$W measurements shown for the first time at LHCP2014, are presented.

Senghi Soares, Mara

2014-01-01

102

Top quark mass measurements  

SciTech Connect

The top quark, with its extraordinarily large mass (nearly that of a gold atom), plays a significant role in the phenomenology of EWSB in the Standard Model. In particular, the top quark mass when combined with the W mass constrains the mass of the as yet unobserved Higgs boson. Thus, a precise determination of the mass of the top quark is a principal goal of the CDF and D0 experiments. With the data collected thus far in Runs 1 and 2 of the Tevatron, CDF and D0 have measured the top quark mass in both the lepton+jets and dilepton decay channels using a variety of complementary experimental techniques. The author presents an overview of the most recent of the measurements.

Hill, Christopher S.; /UC, Santa Barbara

2004-12-01

103

Top physics: CDF results  

SciTech Connect

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.

K. Bloom

2004-06-23

104

Dare we teach tops?  

NASA Astrophysics Data System (ADS)

Tops are mentioned in classical literature and references are even found in the ancient world. For many children a top is one of the first mechanical toys that they play with by themselves, yet a full appreciation of their motion is rare. My hope is that this article will stimulate the reader's interest in tops, will help with the first stages of understanding, and will provide inspiration for looking into the subject further. As a result of this, teachers will be happy and have the confidence to discuss these wonderful toys with their pupils. The article discusses tops and spinning objects of various types, and relates them to some of the physical principles that they demonstrate.

Featonby, David

2010-07-01

105

Spinning the top quark  

NASA Astrophysics Data System (ADS)

We propose to measure the threshold lepton asymmetry, that is the forward-backward asymmetry of the charged lepton in tt¯ events near the production threshold. At threshold, top quark pairs are produced in an s-wave. Angular momentum conservation then implies that the top spins equal the spin of the initial state which—in the case of quarks—is uniquely fixed by the chirality of the initial quarks. Thus, measuring final-state top spins determines the chirality of the quarks which produced them. Information about the top spins can be extracted by measuring the angular distribution of the charged lepton in semileptonic or dileptonic decays of the top pair. One such distribution, the threshold lepton asymmetry, vanishes in tree-level QCD but is nonzero if new physics modifies the relative contribution of right-handed and left-handed quarks to top pair production. This is interesting because realistic models addressing the anomalous tt¯ asymmetry have chiral couplings to light quarks. Models with identical tt¯ asymmetries at the Tevatron can be distinguished by their threshold lepton asymmetries, which range between plus and minus 25% in realistic models.

Falkowski, Adam; Perez, Gilad; Schmaltz, Martin

2013-02-01

106

Convenient access to readily soluble symmetrical dialkyl-substituted ?-oligofurans.  

PubMed

An expedient approach to the synthesis of well soluble symmetrical dialkyl-substituted ?-oligofurans containing up to 8 ?-conjugated furan heterocycles is reported. An ultimate symmetry and high solubility of these ?-oligofurans were guaranteed using the 3,3'-diheptyl-2,2'-bifuran core and its symmetrical elongation through Suzuki-Miyaura or Stille cross-couplings. 3,3'-Diheptyl-2,2'-bifuran was prepared from 2,2'-bifuran-3,3'-dicarbaldehyde by the Wittig olefination and subsequent Pd/C-catalyzed transfer hydrogenation. The most appropriate access to 2,2'-bifuran-3,3'-dicarbaldehyde was achieved through a regioselective lithiation of 3-furanaldehyde acetal followed by CuCl2-induced homocoupling and deprotection. Single crystal X-ray analysis of 2,2'-bifuran-3,3'-dicarbaldehyde revealed anti-arrangement of the furan rings in planar molecules and an unexpected tight herringbone-type packing in crystals. PMID:25030451

Korshin, Edward E; Leitus, Gregory M; Bendikov, Michael

2014-09-14

107

Modeling Symmetric Macromolecular Structures in Rosetta3  

PubMed Central

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

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

2011-01-01

108

Entanglement preparation using symmetric multiports  

NASA Astrophysics Data System (ADS)

We investigate the entanglement produced by a multi-path interferometer that is composed of two symmetric multiports, with phase shifts applied to the output of the first multiport. Particular attention is paid to the case when we have a single photon entering the interferometer. For this situation we derive a simple condition that characterizes the types of entanglement that one can generate. We then show how one can use the results from the single-photon case to determine what kinds of multi-photon entangled states one can prepare using the interferometer.

Brougham, T.; Košt'ák, V.; Jex, I.; Andersson, E.; Kiss, T.

2011-01-01

109

Integrability properties of symmetric-space fields reduced from axially symmetric Einstein and Yang-Mills equations  

SciTech Connect

A gauge-covariant symmetric-space formulation and integrability properties are given for symmetric-space fields reduced from the stationary axially symmetric Einstein equation and static axially symmetric self-dual Yang-Mills equations.

Chau, L.; Chou, K.; Hou, B.; Song, X.

1986-09-15

110

Moving Molecules!  

NSDL National Science Digital Library

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.

Twin Cities Public Television, Inc.

2008-01-01

111

Symmetric Tensor Decomposition Description of Fermionic Many-Body Wavefunctions  

E-print Network

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.

Uemura, Wataru

2012-01-01

112

Two-photon anisotropy: Analytical description and molecular modeling for symmetrical and asymmetrical organic dyes  

Microsoft Academic Search

One- and two-photon anisotropy spectra of a series of symmetrical and asymmetrical polymethine (PD) and fluorene molecules were measured experimentally and discussed theoretically within the framework of three-state and four-state models. For all the molecules discussed in this paper, the experimental two-photon anisotropy values, r2PA, lie in the relatively narrow range from 0.47 to 0.57 and remain almost independent of

Jie Fu; Olga V. Przhonska; Lazaro A. Padilha; David J. Hagan; Eric W. Van Stryland; Kevin D. Belfield; Mikhail V. Bondar; Yuriy L. Slominsky; Alexei D. Kachkovski

2006-01-01

113

Top quark production at CDF  

SciTech Connect

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.

Moed, Shulamit; /Harvard U.

2010-01-01

114

Physics with boosted top quarks  

E-print Network

The production at the LHC of boosted top quarks (top quarks with a transverse momentum that greatly exceeds their rest mass) is a promising process to search for phenomena beyond the Standard Model. In this contribution several examples are discussed of new techniques to reconstruct and identify (tag) the collimated decay topology of the boosted hadronic decays of top quarks. Boosted top reconstruction techniques have been utilized in searches for new physical phenomena. An overview is given of searches by ATLAS, CDF and CMS for heavy new particles decaying into a top and an anti-top quark, vector-like quarks and supersymmetric partners to the top quark.

Elin Bergeaas Kuutmann

2014-08-29

115

TOP MANAGEMENT LEADERSHIP: INSIDE  

Microsoft Academic Search

Based on leadership categorization theory from the cognitive sciences, a partial model of top management leadership is developed. The model looks inside the leadership black box and considers the personal and organizational consequences of matches and mismatches between three levels (superordinate, basic and subordinate) and two dimensions (substantive\\/content and symbolic\\/process) of leadership category prototypes and perceived leadership behaviors. The model

G. HUNT; KIMERLY B. BOAL; RITCH L. SORENSON

116

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.

2000-01-01

117

Ten Top Tech Trends  

ERIC Educational Resources Information Center

In this article, the author discusses the major technical issues, products, and practices of the day. The top ten tech trends are listed and discussed. These include: (1) data mining; (2) cyberbullying; (3) 21st century skills; (4) digital content; (5) learning at leisure; (6) personal responders; (7) mobile tools; (8) bandwidth; (9) open-source…

McLester, Susan

2008-01-01

118

Top Quark Physics  

Microsoft Academic Search

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

Thomas Teubner

1999-01-01

119

Symmetric differential capacitive pressure sensor  

NASA Astrophysics Data System (ADS)

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.

Peters, Randall D.

1993-08-01

120

Walking dynamics are symmetric (enough)  

E-print Network

Many biological phenomena, such as locomotion, circadian cycles, and breathing are quasi-periodic in nature and can be modeled as rhythmic dynamical systems. Dynamical systems modeling often involves neglecting certain characteristics of a physical system as a modeling convenience. For example, in the dynamics of locomotion, the musculoskeletal system is commonly treated as symmetric about the sagittal plane. Here we extend statistical cross validation techniques in order to examine the consequences of assuming (or not) bilateral symmetry. Indeed, we verify that there are statistically significant asymmetries in the dynamics of human walking, but nevertheless show that ignoring these asymmetries results in a more consistent and predictive model. In general, neglecting evident characteristics of a system can be more than a modeling convenience---it can produce a better model.

Ankaral?, M Mert; Madhav, Manu S; Long, Andrew; Bastian, Amy J; Cowan, Noah J

2014-01-01

121

ATLAS results on top properties  

E-print Network

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.

Derue, F; The ATLAS collaboration

2014-01-01

122

TOPs and their regulation.  

PubMed

Upon cell-cycle arrest or nutrient deprivation, the cellular rate of ribosome production is reduced significantly. In mammalian cells, this effect is achieved in part through a co-ordinated inhibition of RP (ribosomal protein) synthesis. More specifically, translation initiation on RP mRNAs is inhibited. Translational regulation of RP synthesis is dependent on cis-elements within the 5'-UTRs (5'-untranslated regions) of the RP mRNAs. In particular, a highly conserved 5'-TOP (5'-terminal oligopyrimidine tract) appears to play a key role in the regulation of RP mRNA translation. This article explores recent developments in our understanding of the mechanism of TOP mRNA regulation, focusing on upstream signalling pathways and trans-acting factors, and highlighting some interesting observations which have come to light following the recent development of cDNA microarray technology coupled with polysome analysis. PMID:16246169

Hamilton, T L; Stoneley, M; Spriggs, K A; Bushell, M

2006-02-01

123

Bart Preneel An introduction to symmetric cryptography  

E-print Network

Bart Preneel An introduction to symmetric cryptography January 2003 1 An Introduction to Symmetric Cryptology Prof. Bart Preneel Katholieke Universiteit Leuven, Belgium Bart.Preneel@esat.kuleuven.ac.be http detectionresponse Data confidentiality Alice Bob Eve Entity authentication BobEve Hello, I am Alice #12;Bart Preneel

Bachoc, Christine

124

COMMUNICATION-AVOIDING SYMMETRIC-INDEFINITE FACTORIZATION  

E-print Network

COMMUNICATION-AVOIDING SYMMETRIC-INDEFINITE FACTORIZATION GREY BALLARD, DULCENEIA BECKER, JAMES and banded. The algorithm is the first symmetric-indefinite communication-avoiding factorization: it performs, communication-avoiding algorithms, Aasen's fac- torization AMS subject classifications. 65F05, 15A23, 65Y20 1

Dongarra, Jack

125

Continuity and Separation in Symmetric Topologies  

ERIC Educational Resources Information Center

In this note, it is shown that in a symmetric topological space, the pairs of sets separated by the topology determine the topology itself. It is then shown that when the codomain is symmetric, functions which separate only those pairs of sets that are already separated are continuous, generalizing a result found by M. Lynch.

Harris, J.; Lynch, M.

2007-01-01

126

CONVEX, ROTATIONALLY SYMMETRIC LIQUID BRIDGES BETWEEN SPHERES  

E-print Network

CONVEX, ROTATIONALLY SYMMETRIC LIQUID BRIDGES BETWEEN SPHERES Thomas I. Vogel Department of Mathematics Texas A&M University College Station, TX 77843 tvogel@math.tamu.edu A liquid bridge between two different contact an- gles: one for each ball). If we consider rotationally symmetric bridges, then the free

Vogel, Thomas

127

Monte Carlo simulations of symmetric and asymmetric angular model liquids  

NASA Astrophysics Data System (ADS)

Monte Carlo simulations of fluids made of nonpolar angular ??? molecules in the NVT ensemble have been performed. They provide quantitative information on the influence of ?? and ?? distances (L?? and L??), temperature and density on the pressure, internal energy, and structural functions of these fluids. Three different models have been considered. The first one is a symmetric angular model of propane with L??=L??=0.4123 in reduced units. A detailed investigation of the thermodynamic and structural properties of this alkane is presented here. The results of the present study are in agreement with those obtained by previous molecular dynamics simulation and with experimental data. The second model consists of nonsymmetrical molecules in which L??=0.4123 and L??=0.6 (reduced units). The third model is a symmetrical one with L??=L??=0.6, a larger distance than for propane. Differences in the critical properties for each model are estimated and differences on the variation of the critical temperature with the molecular shape are discussed. Some preliminary comparisons among simulations and x-ray diffraction experiments in liquid propane are also presented.

Calero, S.; Garzón, B.; Mejías, J. A.; Lago, S.

2001-05-01

128

Intermediate sp-Hybridization for Bonding Configurations in Nonplanar Covalent Molecules  

E-print Network

1 Intermediate sp-Hybridization for Bonding Configurations in Nonplanar Covalent Molecules sp structure in the C3v-symmetrical C2H6 molecule and the bonding configuration in cluster C60 have been of properties of covalent molecules and solids can be calculated at ease. Correspondence should be sent

Zexian, Cao

129

Cloud top entrainment instability and cloud top distributions  

NASA Technical Reports Server (NTRS)

Classical cloud-top entrainment instability condition formulation is discussed. A saturation point diagram is used to investigate the details of mixing in cases where the cloud-top entrainment instability criterion is satisfied.

Boers, Reinout; Spinhirne, James D.

1990-01-01

130

Top quark properties in ATLAS  

E-print Network

Properties of the top quark are measured with the ATLAS detector using LHC proton-proton collisions data. Measurements of the top-quark mass and polarisation, as well as of the polarization of W bosons in top quark decays to probe the Wtb-vertex are presented. In addition, measurements of the spin correlation between top and anti-top quarks as well as of the top- quark charge asymmetry, which constitute important tests of QCD and are sensitive to new physics, are discussed.

Demilly, A; The ATLAS collaboration

2014-01-01

131

Heat conduction of symmetric lattices.  

PubMed

Heat conduction of symmetric Frenkel-Kontorova (FK) lattices with a coupling displacement was investigated. Through simplifying the model, we derived analytical expression of thermal current of the system in the overdamped case. By means of numerical calculations, the results indicate that: (i) As the coupling displacement d equals to zero, temperature oscillations of the heat baths linked with the lattices can control magnitude and direction of the thermal current; (ii) Whether there is a temperature bias or not, the thermal current oscillates periodically with d, whose amplitudes become greater and greater; (iii) As d is not equal to zero, the thermal current monotonically both increases and decreases with temperature oscillation amplitude of the heat baths, dependent on values of d; (iv) The coupling displacement also induces nonmonotonic behaviors of the thermal current vs spring constant of the lattice and coupling strength of the lattices; (v) These dynamical behaviors come from interaction of the coupling displacement with periodic potential of the FK lattices. Our results have the implication that the coupling displacement plays a crucial role in the control of heat current. PMID:23848662

Nie, Linru; Yu, Lilong; Zheng, Zhigang; Shu, Changzheng

2013-06-01

132

Intermittency on catalysts: symmetric exclusion  

E-print Network

We continue our study of intermittency for the parabolic Anderson equation $\\partial u/\\partial t = \\kappa\\Delta u + \\xi u$, where $u\\colon \\Z^d\\times [0,\\infty)\\to\\R$, $\\kappa$ is the diffusion constant, $\\Delta$ is the discrete Laplacian, and $\\xi\\colon \\Z^d\\times [0,\\infty)\\to\\R$ is a space-time random medium. The solution of the equation describes the evolution of a ``reactant'' $u$ under the influence of a ``catalyst'' $\\xi$. In this paper we focus on the case where $\\xi$ is exclusion with a symmetric random walk transition kernel, starting from equilibrium with density $\\rho\\in (0,1)$. We consider the annealed Lyapunov exponents, i.e., the exponential growth rates of the successive moments of $u$. We show that these exponents are trivial when the random walk is recurrent, but display an interesting dependence on the diffusion constant $\\kappa$ when the random walk is transient, with qualitatively different behavior in different dimensions. Special attention is given to the asymptotics of the exponents for $\\kappa\\to\\infty$, which is controlled by moderate deviations of $\\xi$ requiring a delicate expansion argument. In G\\"artner and den Hollander \\cite{garhol04} the case where $\\xi$ is a Poisson field of independent (simple) random walks was studied. The two cases show interesting differences and similarities. Throughout the paper, a comparison of the two cases plays a crucial role.

J. Gaertner; F. den Hollander; G. Maillard

2006-05-24

133

Top physics results at CDF  

SciTech Connect

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.

Vickey, Trevor; /Illinois U., Urbana

2005-05-01

134

Top Physics at the LHC  

E-print Network

Top quark physics will be a prominent topic in Standard Model physics at the LHC. The enormous amount of top quarks expected to be produced will allow to perform a wide range of precision measurements. An overview of the planned top physics programme of the ATLAS and CMS experiments at the LHC is given.

Christian Weiser

2005-06-10

135

Computing Z_top  

E-print Network

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.

Kashani-Poor, Amir-Kian

2014-01-01

136

Computing Z_top  

E-print Network

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.

Amir-Kian Kashani-Poor

2014-08-06

137

Plane symmetric analogue of NUT space  

E-print Network

In this article on the basis of a new definition of spacetime symmetry, which is in accordance with the symmetry of the curvature invariants, we investigate exact vacuum solutions of Einstein field equations corresponding to both static and stationary plane symmetric spacetimes using the concepts of the (1+3)-decomposition or threading formalism. Demanding the presence of a plane symmetric gravitomagnetic field we find a family of two parameter (m and l) solutions, every member of which being the plane symmetric analogue of NUT space.

Mohammad Nouri-Zonoz; Ali Reza Tavanfar

2001-05-24

138

Discussion: Time-Symmetric Quantum Counterfactuals  

E-print Network

There is a trend to consider counterfactuals as invariably time-asymmetric. Recently, this trend manifested itself in the controversy about validity of counterfactual application of a time-symmetric quantum probability rule. Kastner (2003) analyzed this controversy and concluded that there are time-symmetric quantum counterfactuals which are consistent, but they turn out to be trivial. I correct Kastner's misquotation of my defense of time-symmetric quantum counterfactuals and explain their non-trivial aspects, thus contesting the claim that counterfactuals have to be time-asymmetric.

Lev Vaidman

2014-01-24

139

The Design and Synthesis of Highly Branched and Spherically Symmetric Fluorinated Oils and Amphiles  

PubMed Central

A new emulsifier design principle, based on concepts borrowed from protein science, is proposed. Using this principle, a class of highly branched and spherically symmetric fluorinated oils and amphiles has been designed and synthesized, for potential applications in the construction of fluorocarbon nanoparticles. The Mitsunobu reaction was employed as the key step for introducing three perfluoro-tert-butoxyl groups into pentaerythritol derivatives with excellent yields and extremely simple isolation procedures. Due to the symmetric arrangement of the fluorine atoms, each fluorinated oil or amphile molecule gives one sharp singlet 19F NMR signal. PMID:18461118

Jiang, Zhong-Xing; Yu, Y. Bruce

2007-01-01

140

Top quark mass measurements  

SciTech Connect

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}.

L. Cerrito

2004-07-16

141

Top quark physics at CDF  

SciTech Connect

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.

Potamianos, Karolos

2011-12-01

142

A survey of spherically symmetric spacetimes  

NASA Astrophysics Data System (ADS)

We survey many of the important properties of spherically symmetric spacetimes as follows. We present several different ways of describing a spherically symmetric spacetime and the resulting metrics. We then focus our discussion on an especially useful form of the metric of a spherically symmetric spacetime in polar-areal coordinates and its properties. In particular, we show how the metric component functions chosen are extremely compatible with notions in Newtonian mechanics. We also show the monotonicity of the Hawking mass in these coordinates. As an example, we discuss how these coordinates and the metric can be used to solve the spherically symmetric Einstein-Klein-Gordon equations. We conclude with a brief mention of some applications of these properties.

Parry, Alan R.

2014-12-01

143

On Radially Symmetric Solutions to Conservation Laws  

Microsoft Academic Search

\\u000a Radially symmetric solutions to multi-dimensional systems of conservations laws are important in applications and computations,\\u000a as well as in the general theory of conservative systems. Notwithstanding their one-dimensional nature they are poorly understood.\\u000a In particular this is true for the Euler equations in gas-dynamics. After a short review of symmetric solutions to the Euler\\u000a system, we introduce a scalar model

Helge Kristian Jenssen

144

A single-molecule diode  

PubMed Central

We have designed and synthesized a molecular rod that consists of two weakly coupled electronic ? -systems with mutually shifted energy levels. The asymmetry thus implied manifests itself in a current–voltage characteristic with pronounced dependence on the sign of the bias voltage, which makes the molecule a prototype for a molecular diode. The individual molecules were immobilized by sulfur–gold bonds between both electrodes of a mechanically controlled break junction, and their electronic transport properties have been investigated. The results indeed show diode-like current–voltage characteristics. In contrast to that, control experiments with symmetric molecular rods consisting of two identical ? -systems did not show significant asymmetries in the transport properties. To investigate the underlying transport mechanism, phenomenological arguments are combined with calculations based on density functional theory. The theoretical analysis suggests that the bias dependence of the polarizability of the molecule feeds back into the current leading to an asymmetric shape of the current–voltage characteristics, similar to the phenomena in a semiconductor diode. PMID:15956208

Elbing, Mark; Ochs, Rolf; Koentopp, Max; Fischer, Matthias; von Hanisch, Carsten; Weigend, Florian; Evers, Ferdinand; Weber, Heiko B.; Mayor, Marcel

2005-01-01

145

Top quark physics  

SciTech Connect

Most of the material presented in this report, comes from contributions to the parallel session PL20 of this conference. We summarise the experimental results of direct production of Top quarks, coming from the CDF and C0 Collaborations at Fermilab, and compare these results to what one expects within current theoretical understanding. Particular attention is given to new results such as all hadronic modes of t{bar t} decay. As far as the mass is concerned, a comparison is made with precision measurements of related quantities, coming from LEP and other experiments. An attempt is made to look at the medium-term future and understand which variables and with what accuracy one can measure them with increased integrated luminosity.

Menzione, A. [INFN Sezione di Pisa (Italy)

1995-10-01

146

Heat conduction in a symmetric body subjected to a current flow of symmetric input and output  

Microsoft Academic Search

Steady heat conduction in symmetrical electro-thermal problems is analyzed under the influence of a steady direct current passing through symmetrical regions of the boundary. In the present approach, solution is obtained by dividing the temperature field of the electro-thermal problem into two fields—one is related to the heat conduction problem without Joule heating and the other corresponds to a symmetric

M. Saka; Y. X. Sun; S. Reaz Ahmed

2009-01-01

147

"Super"--Dilatation Symmetry of the Top-Higgs System  

NASA Astrophysics Data System (ADS)

The top-Higgs system, consisting of top quark (LH doublet, RH singlet) and Higgs boson kinetic terms, with gauge fields set to zero, has an exact symmetry where both fermion and Higgs fields are shifted and mixed in a supersymmetric fashion. The full Higgs-Yukawa interaction and Higgs-potential, including additional ˜1/?2 NJL-like interactions, also has this symmetry to \\ {O} (1/{? ^4}), up to null-operators. Thus the interaction Lagrangian can be viewed as a power series in 1/?2. The symmetry involves interplay of the Higgs quartic interaction with the Higgs-Yukawa interaction and implies the relationship, ? = {1 over 2}{g^2} between the top-Yukawa coupling, g, and Higgs quartic coupling, ?, at a high energy scale ? ˜ few TeV. We interpret this to be a new physics scale. The top quark is massless in the symmetric phase, satisfying the Nambu-Goldstone theorem. The fermionic shift part of the current is ?(1-H†H/v2), owing to the interplay of ? and g, and vanishes in the broken phase. Hence the Nambu-Goldstone theorem is trivially evaded in the broken phase and the top quark becomes heavy (it is not a Goldstino). We have mt = mh, subject to radiative corrections that can in principle pull the Higgs into concordance with experiment.

Hill, Christopher T.

148

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

SciTech Connect

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.

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

2000-06-21

149

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

PubMed Central

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

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

2012-01-01

150

Top physics results from CDF  

SciTech Connect

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.

Gomez, Gervasio; /Cantabria Inst. of Phys.

2005-05-01

151

Controlling polar molecules in optical lattices  

SciTech Connect

We theoretically investigate the interaction of polar molecules with optical lattices and microwave fields. We demonstrate the existence of frequency windows in the optical domain where the complex internal structure of the molecule does not influence the trapping potential of the lattice. In such frequency windows the Franck-Condon factors are so small that near-resonant interaction of vibrational levels of the molecule with the lattice fields have a negligible contribution to the polarizability, and light-induced decoherences are kept to a minimum. In addition, we show that microwave fields can induce a tunable dipole-dipole interaction between ground-state rotationally symmetric (J=0) molecules. A combination of a carefully chosen lattice frequency and microwave-controlled interaction between molecules will enable trapping of polar molecules in a lattice and possibly realize molecular quantum logic gates. Our results are based on ab initio relativistic electronic structure calculations of the polar KRb and RbCs molecules combined with calculations of their rovibrational motion.

Kotochigova, S. [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States); National Institute of Standards and Technology, 100 Bureau Drive, Stop 8423, Gaithersburg, Maryland 20899 (United States); Tiesinga, E. [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States)

2006-04-15

152

Controlling Polar Molecules in Optical Lattices  

E-print Network

We investigate theoretically the interaction of polar molecules with optical lattices and microwave fields. We demonstrate the existence of frequency windows in the optical domain where the complex internal structure of the molecule does not influence the trapping potential of the lattice. In such frequency windows the Franck-Condon factors are so small that near-resonant interaction of vibrational levels of the molecule with the lattice fields have a negligible contribution to the polarizability and light-induced decoherences are kept to a minimum. In addition, we show that microwave fields can induce a tunable dipole-dipole interaction between ground-state rotationally symmetric (J=0) molecules. A combination of a carefully chosen lattice frequency and microwave-controlled interaction between molecules will enable trapping of polar molecules in a lattice and possibly realize molecular quantum logic gates. Our results are based on ab initio relativistic electronic structure calculations of the polar KRb and RbCs molecules combined with calculations of their rovibrational motion.

S. Kotochigova; E. Tiesinga

2006-02-01

153

Topics in Top Quark Physics  

E-print Network

The status of top quark searches will be briefly reviewed. Theoretical predictions for the top quark decay rate are presented including QCD and electroweak radiative corrections. The possibilities for quarkonium searches at an hadron collider will be discussed. The perspectives for top production at an electron positron collider will be described in detail with emphasis on the behavior of the cross section and decay distribution in the threshold region.

J. H. Kühn

1993-07-14

154

Top quark search at CDF  

SciTech Connect

The current status of the Top quark search at CDF is presented. A lower limit on the Top mass of 113 GeV has been established using the dilepton channel with the data collected during the 1988--1989 and 1992--1993 runs at {radical}s= 1.8 TeV. Prospects for Top quark discovery during the 1993--1994 run are also outlined.

Benlloch, J.M. [Massachusetts Inst. of Technology, Cambridge, MA (United States); CDF Collaboration

1993-11-01

155

High resolution laser spectroscopy of selected molecules in the gas phase  

NASA Astrophysics Data System (ADS)

In this thesis, various types of metal-bearing molecules (diatomic, linear poly-atomic, and symmetric top) have been studied via high-resolution laser spectroscopy. The molecules were produced in either a Broida oven or in a supersonic jet created in a laser ablation apparatus. The motivations for the studies ranged from basic studies of metal-ligand bonding and validation of theoretical calculations on the structure of metal-bearing molecules, to applications in catalysis and in the characterization of astrophysically relevant species. Two diatomic molecules were investigated: SmO and IrS. SmO was produced in the Broida oven, and three new electronically excited states ([15.3] 1, [15.6] 2 and [16.2] 2) were characterized, adding to the seven excited states and twelve low lying states previously observed and analyzed by Guo et al. [1]. Seventeen bands of 193IrS and eleven of the 191 IrS isotopologue were observed in experiments conducted using the laser ablation source apparatus, but the analysis has not yet led to a conclusive identification of the ground electronic state nor to a definite description of the low-lying electronically excited state just above the ground state. A combination of experimental data and theoretical calculations suggest that these two low lying states may be identified as 2Delta 5/2 and 4Delta7/2. Isotopologues of the linear polyatomics MgCCH, CaCCH and SrCCH were also examined to precisely determine the bond lengths in these molecules. Analyses of the Mg12C12CD, Mg13C 13CH, Ca13C13CH and Sr13C 13CH spectra presented in this thesis were combined with those from previously observed spectra of the normal and deuterated isotopes. Surprisingly, the results showed an unexpected and significant increase in the C-C bond length as the alkaline earth metal changed from Mg to Ca to Sr. A more physically realistic result in which the C-C lengths were more consistent from metal to metal was obtained when the analysis was performed with the C-H bond length constrained to that of HCCH. While scanning spectra of MgCCH, bands of longer magnesium-bearing molecules MgC4H and MgC6H were observed as well. The signal strength was sufficient in MgC4H to obtain and analyze its rotationally resolved spectrum. Finally, on the basis of the work done by Hopkins et al [3], the symmetric top molecule strontium monomethoxide was scanned at high resolution. A two-laser optical-optical double resonance technique was employed to conclusively assign and analyze the A2E -- X˜2A1 spectrum in SrO12CH3 and the B˜ 2A1 -- X˜ 2A1 spectrum in SrO 12CH3 and SrO13CH3. A strong perturbation, the origin of which is still unknown, was observed in the B˜2A1 state in SrO 12CH3, which exhibits as well the Jahn-Teller effect in its A2E state, through the Jahn-Teller related rotational parameter h1. An empirical deperturbation was successfully performed by introducing a new parameter Bmod into the Hamiltonian, which adjusted the rotational constant B for one parity component of a specific set of K' levels.

Forthomme, Damien

156

Properties of the top quark  

NASA Astrophysics Data System (ADS)

The top quark was discovered 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.

Wicke, Daniel

2011-05-01

157

Top Quark Properties from Top Pair Events and Decays  

Microsoft Academic Search

Over a decade since the discovery of the top quark we are still trying to unravel mysteries of the heaviest observed particle and learn more about its nature. The continuously accumulating statistics of CDF and Dzero data provide the means for measuring top quark properties with ever greater precision and the opportunity to search for signs of new physics that

Andrew G. Ivanov; for the CDF

2008-01-01

158

Top Quark Properties from Top Pair Events and Decays  

Microsoft Academic Search

Over a decade since the discovery of the top quark we are still trying to unravel mysteries of the heaviest observed particle and learn more about its nature. The continuously accumulating statistics of CDF and DO data provide the means for measuring top quark properties with ever greater precision and the opportunity to search for signs of new physics that

Andrew G. Ivanov; for the CDF

2008-01-01

159

Majorana representation of symmetric multiqubit states  

E-print Network

As early as 1932, Majorana had proposed that a pure permutation symmetric state of N spin- 1 2 particles can be represented by N spinors, which correspond geometrically to N points on the Bloch sphere. Several decades after its conception, the Majorana representation has recently attracted a great deal of attention in connection with multiparticle entanglement. A novel use of this represen- tation led to the classification of entanglement families of permutation symmetric qubits - based on the number of distinct spinors and their arrangement in constituting the multiqubit state. An elegant approach to explore how correlation information of the whole pure symmetric state gets imprinted in its parts is developed for specific entanglement classes of symmetric states. More- over, an elegant and simplified method to evaluate geometric measure of entanglement in N-qubit states obeying exchange symmetry has been developed based on the distribution of the constituent Majorana spionors over the unit sphere. Multiparticle entanglement being a key resource in sev- eral quantum information processing tasks, its deeper understanding is essential. In this review, we present a detailed description of the Majorana representation of pure symmetric states and its applicability in investigating various aspects of multiparticle entanglement.

A. R. Usha Devi; Sudha; A. K. Rajagopal

2011-03-18

160

Systems of coupled PT-symmetric oscillators  

NASA Astrophysics Data System (ADS)

The Hamiltonian for a PT-symmetric chain of coupled oscillators is constructed. It is shown that if the loss-gain parameter ? is uniform for all oscillators, then as the number of oscillators increases, the region of unbroken PT symmetry disappears entirely. However, if ? is localized in the sense that it decreases for more distant oscillators, then the unbroken PT-symmetric region persists even as the number of oscillators approaches infinity. In the continuum limit the oscillator system is described by a PT-symmetric pair of wave equations, and a localized loss-gain impurity leads to a pseudobound state. It is also shown that a planar configuration of coupled oscillators can have multiple disconnected regions of unbroken PT symmetry.

Bender, Carl M.; Gianfreda, Mariagiovanna; Klevansky, S. P.

2014-08-01

161

Symmetric extension of two-qubit states  

NASA Astrophysics Data System (ADS)

A bipartite state ?AB is symmetric extendible if there exists a tripartite state ?ABB' whose AB and AB' marginal states are both identical to ?AB. Symmetric extendibility of bipartite states is of vital importance in quantum information because of its central role in separability tests, one-way distillation of Einstein-Podolsky-Rosen pairs, one-way distillation of secure keys, quantum marginal problems, and antidegradable quantum channels. We establish a simple analytic characterization for symmetric extendibility of any two-qubit quantum state ?AB; specifically, tr(?B2)?tr(?AB2)-4? det?AB . As a special case we solve the bosonic three-representability problem for the two-body reduced density matrix.

Chen, Jianxin; Ji, Zhengfeng; Kribs, David; Lütkenhaus, Norbert; Zeng, Bei

2014-09-01

162

Spherically Symmetric Thick Branes Cosmological Evolution  

E-print Network

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...

Bernardini, Alex E; da Rocha, Roldao

2014-01-01

163

TOPS: television object promoting system  

Microsoft Academic Search

In this short paper, we propose the Television Object Promoting system (TOPS), a What You See Is What You Get (WYSIWYG) user interface and user experience designed for users to interact with objects in TV programs. Using TOPS while watching TV, consumers can acquire informa-tion about objects appearing in TV programs, such as mer-chandise, people, and scenic spots. Moreover, consumers

Tun-Hao You; Yi-Jui Wu; Yi-Jen Yeh

2011-01-01

164

Personalized top-k processing  

E-print Network

Personalized top-k processing: from centralized to decentralized systems Thèse soutenue le 08 MATISSE tel-00545642,version1-10Dec2010 #12;tel-00545642,version1-10Dec2010 #12;Personalized top-of-the-art on personalized and/or decentralized search . . . . . . . . . . . . . 9 1.3.1 Personalized search

Paris-Sud XI, Université de

165

Symmetric and irregular aromatic silicon nanoclusters  

NASA Astrophysics Data System (ADS)

Based on first-principles calculations, we predict the existence of two classes of aromatic hydrogenated silicon nanoclusters. Despite their completely different structure, they both exhibit quite comparable physical and chemical properties due to the common presence of overcoordinated silicon atoms inducing extensive electron delocalization. Due to a complex interplay between strain relaxation and aromatic stabilization, apparently ill-defined nanoclusters might sometimes turn out to be more stable than their symmetric counterparts. Both symmetric and irregular aromatic silicon nanoclusters are extremely stable at ambient conditions and might readily find applications in future nano-technological devices.

Vach, Holger

2014-10-01

166

Observational tests of Baryon symmetric cosmology  

NASA Technical Reports Server (NTRS)

Observational evidence for Baryon symmetric (matter/antimatter) cosmology and future observational tests are reviewed. The most significant consequences of Baryon symmetric cosmology lie in the prediction of an observable cosmic background of gamma radiation from the decay of pi(0)-mesons produced in nucleon-antinucleon annihilations. Equations for the prediction of the amma ray background spectrum for the case of high redshifts are presented. The theoretical and observational plots of the background spectrum are shown to be in good agreement. Measurement of cosmic ray antiprotons and the use of high energy neutrino astronomy to look for antimatter elsewhere in the universe are also addressed.

Stecker, F. W.

1982-01-01

167

Symmetric integrator for nonintegrable Hamiltonian relativistic systems  

NASA Astrophysics Data System (ADS)

By combining a standard symmetric, symplectic integrator with a new step size controller, we provide an integration scheme that is symmetric, reversible and conserves the values of the constants of motion. This new scheme is appropriate for long-term numerical integrations of geodesic orbits in spacetime backgrounds, whose corresponding Hamiltonian system is nonintegrable, and, in general, for any nonintegrable Hamiltonian system whose kinetic part depends on the position variables. We show by numerical examples that the new integrator is faster and more accurate (i) than the standard symplectic integration schemes with or without standard adaptive step size controllers and (ii) than an adaptive step Runge-Kutta scheme.

Seyrich, Jonathan; Lukes-Gerakopoulos, Georgios

2012-12-01

168

Rational top and its classical r-matrix  

NASA Astrophysics Data System (ADS)

We construct a rational integrable system (the rational top) on a co-adjoint orbit of SL N Lie group. It is described by the Lax operator with spectral parameter and classical non-dynamical skew-symmetric r-matrix. In the case of the orbit of minimal dimension the model is gauge equivalent to the rational Calogero-Moser (CM) system. To obtain the results we represent the Lax operator of the CM model in two different factorized forms—without spectral parameter (related to the spinless case) and another one with the spectral parameter. The latter gives rise to the rational top while the first one is related to generalized Cremmer-Gervais r-matrices. The gauge transformation relating the rational top and CM model provides the classical rational version of the IRF-Vertex correspondence. From the geometrical point of view it describes the modification of SL(N,{C})-bundles over degenerated elliptic curve. In view of the Symplectic Hecke Correspondence the rational top is related to the rational spin CM model. Possible applications and generalizations of the suggested construction are discussed. In particular, the obtained r-matrix defines a class of KZB equations.

Aminov, G.; Arthamonov, S.; Smirnov, A.; Zotov, A.

2014-08-01

169

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

SciTech Connect

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.

Boisvert, V.; /Rochester U.

2006-08-01

170

Frustration in bilayers and topologies of liquid crystals of amphiphilic molecules  

E-print Network

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

Paris-Sud XI, Université de

171

Properties of the top quark  

E-print Network

Recent measurements of top-quark properties at the LHC and the Tevatron are presented. Most recent measurements of the top quark mass have been carried out by CMS using $19.7/$fb of $\\sqrt{s} = 8$ TeV data including the study of the dependence on event kinematics. ATLAS uses the full Run I data at $\\sqrt{s} = 7$ TeV for a "3D" measurement that significantly reduces systematic uncertainties. D0 employs the full Run II data using the matrix element method to measure the top quark mass with significantly reduced systematic uncertainties. Many different measurements of the top quark exist to date and the most precise ones per decay channel per experiment have been combined into the first world combination with a relative precision of 0.44\\%. Latest updates of measurements of production asymmetries include the measurement of the \\ttbar production asymmetry by D0 employing the full Run II data set, by CMS and ATLAS (including the polarization of the top quark) employing both the full data set at $\\sqrt{s} = 7$ TeV. CMS uses the full $\\sqrt{s} = 8$ TeV data to measure the top quark polarization in single top production, the ratio ${\\cal R}$ of the branching fractions ${\\cal B}(t \\rightarrow Wb) / {\\cal B}(t \\rightarrow Wq)$ and to search for flavor changing neutral currents. The results from all these measurements agree well with their respective Standard Model expectation.

A. W. Jung

2014-09-24

172

Better Hadronic Top Quark Polarimetry  

E-print Network

Observables sensitive to top quark polarization are important for characterizing or even discovering new physics. The most powerful spin analyzer in top decay is the down-type fermion from the W, which in the case of leptonic decay allows for very clean measurements. However, in many applications it is useful to measure the polarization of hadronically decaying top quarks. Usually it is assumed that at most 50% of the spin analyzing power can be recovered in this case. This paper introduces a simple and truly optimal hadronic spin analyzer, with a power of 64% at leading-order. The improvement is demonstrated to be robust in a handful of simulated measurements, including the spins and spin correlations of boosted top quarks from multi-TeV top-antitop resonances, the spins of semi-boosted tops from chiral stop decays, and the potentially CP-violating spin correlations induced in continuum top pairs by color dipole operators. For the boosted studies, we explore jet substructure techniques that exhibit improved mapping between subjets and quarks.

Brock Tweedie

2014-01-13

173

Light top squark in precision top quark sample  

NASA Astrophysics Data System (ADS)

The uncertainty of tt ¯ production cross section measurement at LHC is at a few percent level which still allows the stop pair production t ˜t ˜* with identical final states 2b +?+nj+notation="updiagonalstrike">ET. In this paper, we attempt to use the existing measurement of W-polarization in top quark decay to improve the distinction between stop and top quark states. We apply the ATLAS ?2 method of W-polarization measurement in semileptonic tt ¯ final state to semileptonic stop pair samples and study its prediction. We find that the faked top events from stop mostly contribute to the left-handed polarized W due to the reconstruction. The benchmark point with maximal contribution to top events only changes FL by 1%. After comparing with the current experiments, we conclude that the current measurement of W-polarization in t decay cannot exclude the light stop scenario.

Li, Xue-Qian; Si, Zong-Guo; Wang, Kai; Wang, Liucheng; Zhang, Liangliang; Zhu, Guohuai

2014-04-01

174

A Concrete Security Treatment of Symmetric Encryption  

Microsoft Academic Search

We study notions and schemes for symmetric (ie. private key) encryption in a concrete security framework. We give four different notions of security against chosen plaintext attack and analyze the concrete complexity of reductions among them, providing both upper and lower bounds, and obtaining tight relations. In this way we classify notions (even though polynomially reducible to each other) as

Mihir Bellare; Anand Desai; E. Jokipii; Phillip Rogaway

1997-01-01

175

Resonances for Symmetric Two-Barrier Potentials  

ERIC Educational Resources Information Center

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…

Fernandez, Francisco M.

2011-01-01

176

Amplituhedron cells and Stanley symmetric functions  

E-print Network

The amplituhedron was recently introduced in the study of scattering amplitudes in $N=4$ super Yang-Mills. We compute the cohomology class of a tree amplituhedron subvariety of the Grassmannian to be the truncation of an affine Stanley symmetric function.

Thomas Lam

2014-08-23

177

ccsd00002799, KILLING FORMS ON SYMMETRIC SPACES  

E-print Network

de#12;nitions of Killing vector #12;elds on Riemannian manifolds. A vector #12;eld X is Killing AND UWE SEMMELMANN Proposition 1.2. A symmetric space admitting real Killing spinors is locally confor carry Killing spinors is locally irreducible (cf. [3]) and using the squaring construction one can

178

ECG compression using discrete symmetric wavelet transform  

Microsoft Academic Search

This paper proposes a new ECG signal compression algorithm using a discrete symmetric wavelet transform. This proposed compression scheme may find applications in digital Holter recording, in ECG signal archiving and in ECG data transmission through communication channels. Using the new method, a compression ratio of 8 to 1 can be achieved with PRD=3.9%, in contrast to the AZTEC compression

A. Djohan; T. Q. Nguyen; W. J. Tompkins

1995-01-01

179

Symmetries of Locally Rotationally Symmetric Models  

E-print Network

Matter collineations of locally rotationally symmetric spacetimes are considered. These are investigated when the energy-momentum tensor is degenerate. We know that the degenerate case provides infinite dimensional matter collineations in most of the cases. However, an interesting case arises where we obtain proper matter collineations. We also solve the constraint equations for a particular case to obtain some cosmological models.

M. Sharif

2005-06-08

180

Reciprocal Symmetric and Origin of Quantum Statistics  

E-print Network

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.

Mushfiq Ahmad

2007-03-21

181

Network Organizations: Symmetric Cooperation or Multivalent Negotiation?  

E-print Network

Network Organizations: Symmetric Cooperation or Multivalent Negotiation? Hamid R. Ekbia1 & Rob-169 Abstract The network model of organization plays a central role in recent sociological accounts and technology intensive. Such themes are normally based on a "networking logic" that assumes the trustful

Indiana University

182

Dissociative Recombination of Highly Symmetric Polyatomic Ions  

NASA Astrophysics Data System (ADS)

A general first-principles theory of dissociative recombination is developed for highly symmetric molecular ions and applied to H3O+ and CH3+, which play an important role in astrophysical, combustion, and laboratory plasma environments. The theoretical cross sections obtained for the dissociative recombination of the two ions are in good agreement with existing experimental data from storage ring experiments.

Douguet, Nicolas; Orel, Ann E.; Greene, Chris H.; Kokoouline, Viatcheslav

2012-01-01

183

Acoustic horizons in axially symmetric relativistic accretion  

Microsoft Academic Search

Transonic accretion onto astrophysical objects is a unique example of an analogue black hole realized in nature. In the framework of acoustic geometry, we study axially symmetric accretion and wind of a rotating astrophysical black hole or of a neutron star assuming isentropic flow of a fluid described by a polytropic equation of state. In particular, we analyse the causal

Hrvoje Abraham; Neven Bili?; Tapas K. Das

2006-01-01

184

Geometry of PT-symmetric quantum mechanics  

Microsoft Academic Search

Recently, much research has been carried out on Hamiltonians that are not Hermitian but are symmetric under space-time reflection, that is, Hamiltonians that exhibit PT symmetry. Investigations of the Sturm-Liouville eigenvalue problem associated with such Hamiltonians have shown that in many cases the entire energy spectrum is real and positive and that the eigenfunctions form an orthogonal and complete basis.

Carl M. Bender; Dorje C. Brody; Bernhard K. Meister

2007-01-01

185

Entanglement classes of symmetric Werner states  

SciTech Connect

The symmetric Werner states for n qubits, important in the study of quantum nonlocality and useful for applications in quantum information, have a surprisingly simple and elegant structure in terms of tensor products of Pauli matrices. Further, each of these states forms a unique local unitary equivalence class, that is, no two of these states are interconvertible by local unitary operations.

Lyons, David W.; Walck, Scott N. [Lebanon Valley College, Annville, Pennsylvania 17003 (United States)

2011-10-15

186

Entanglement classes of symmetric Werner states  

E-print Network

The symmetric Werner states for $n$ qubits, important in the study of quantum nonlocality and useful for applications in quantum information, have a surprisingly simple and elegant structure in terms of tensor products of Pauli matrices. Further, each of these states forms a unique local unitary equivalence class, that is, no two of these states are interconvertible by local unitary operations.

David W. Lyons; Scott N. Walck

2011-06-21

187

Iris Recognition Using Circular Symmetric Filters  

Microsoft Academic Search

This paper proposes a new method for personal identification based on iris recognition. The method consists of three major components: image preprocessing, feature extraction and classifier design. A bank of circular symmetric filters is used to capture local iris characteristics to form a fixed length feature vector. In iris matching, an efficient approach called nearest feature line (NFL) is used.

Li Ma; Yunhong Wang; Tieniu Tan

2002-01-01

188

Top coat or no top coat for immersion lithography?  

NASA Astrophysics Data System (ADS)

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.

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

189

Symmetric curvature descriptors for label-free analysis of DNA  

NASA Astrophysics Data System (ADS)

High-resolution microscopy techniques such as electron microscopy, scanning tunnelling microscopy and atomic force microscopy represent well-established, powerful tools for the structural characterization of adsorbed DNA molecules at the nanoscale. Notably, the analysis of DNA contours allows mapping intrinsic curvature and flexibility along the molecular backbone. This is particularly suited to address the impact of the base-pairs sequence on the local conformation of the strands and plays a pivotal role for investigations relating the inherent DNA shape and flexibility to other functional properties. Here, we introduce novel chain descriptors aimed to characterize the local intrinsic curvature and flexibility of adsorbed DNA molecules with unknown orientation. They consist of stochastic functions that couple the curvatures of two nanosized segments, symmetrically placed on the DNA contour. We show that the fine mapping of the ensemble-averaged functions along the molecular backbone generates characteristic patterns of variation that highlight all pairs of tracts with large intrinsic curvature or enhanced flexibility. We demonstrate the practical applicability of the method for DNA chains imaged by atomic force microscopy. Our approach paves the way for the label-free comparative analysis of duplexes, aimed to detect nanoscale conformational changes of physical or biological relevance in large sample numbers.

Buzio, Renato; Repetto, Luca; Giacopelli, Francesca; Ravazzolo, Roberto; Valbusa, Ugo

2014-09-01

190

Molecule of the Month  

NSDL National Science Digital Library

From the University of Bristol's School of Chemistry, this site features a new molecule each month. For example, the molecule for April is Melatonin. Each molecule comes with a link to a Webpage from a university or commercial site containing further information. (Links may require Chime, VRML, or Java.) Contributors may submit molecule pages to be considered in future months. Monthly molecules date back to January 1996.

191

Visiting the top modern observatories  

NASA Astrophysics Data System (ADS)

The lecture entitled Visiting the top modern observatories has been prepared for the coming International Year of Astronomy 2009 and covers such topics as: what one can see through a telescope; the thrills of using a telescope; the basic principles of telescope construction; the history of the telescope: its invention and development through 400 years; Earth's atmospheric transparency; radio telescopes; the top 10 optical telescopes of the planet; Ukrainian observatories; large telescopes of the near future; space telescopes and their discoveries. We present some parts of the script from the Kiev planetarium lecture Visiting the top modern observatories.

Kovalenko, N.

2008-06-01

192

IONIZATION OF NITROGEN MOLECULES BY NITROGEN MOLECULES  

Microsoft Academic Search

The ionization cross section for Nâ molecules on impact with N\\/sub ; 2\\/ molecules was measured over the laboratory energy range from 30 to 1000 ev. ; The incident molecular beam was produced by the technique of ionization by ; electron impact, electrostatic acceleration and neutralization by charge transfer. ; The measurements were carried out in a low-pressure parallel plate

Nyle Utterback; Glenn Miller

1961-01-01

193

Symmetric and skew-symmetric weight functions in perturbation models of 2D interfacial cracks  

E-print Network

In this paper we address the vector problem of a 2D interfacial crack loaded by a general asymmetric distribution of forces acting on its faces. It is shown that the general integral formula for the evaluation of stress intensity factors, as well as high-order terms, requires both symmetric and skew-symmetric weight function matrices. The symmetric weight function matrix is obtained via the solution of a Wiener-Hopf functional equation, whereas the derivation of the skew-symmetric weight function matrix requires the construction of the corresponding full field singular solution. The weight function matrices are then used in the perturbation analysis of a crack advancing quasi-statically along the interface between two dissimilar media. A general and rigorous asymptotic procedure is developed to compute the perturbations of stress intensity factors as well as high-order terms.

Piccolroaz, A; Movchan, A B

2008-01-01

194

Symmetric and skew-symmetric weight functions in perturbation models of 2D interfacial cracks  

E-print Network

In this paper we address the vector problem of a 2D half-plane interfacial crack loaded by a general asymmetric distribution of forces acting on its faces. It is shown that the general integral formula for the evaluation of stress intensity factors, as well as high-order terms, requires both symmetric and skew-symmetric weight function matrices. The symmetric weight function matrix is obtained via the solution of a Wiener-Hopf functional equation, whereas the derivation of the skew-symmetric weight function matrix requires the construction of the corresponding full field singular solution. The weight function matrices are then used in the perturbation analysis of a crack advancing quasi-statically along the interface between two dissimilar media. A general and rigorous asymptotic procedure is developed to compute the perturbations of stress intensity factors as well as high-order terms.

A. Piccolroaz; G. Mishuris; A. B. Movchan

2008-12-24

195

Dark decay of Top quark  

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.

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

2014-04-01

196

WebTOP Polarization Tutorial  

NSDL National Science Digital Library

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.

Behringer, Ernest

2010-03-22

197

Properties of the Top Quark  

NASA Astrophysics Data System (ADS)

The top quark is the heaviest known elementary particle, and it is often considered a window through which to search for new physics processes in particle physics. A large program to study the top quark properties has been carried out at both the Tevatron and LHC colliders by the D0, CDF, ATLAS, and CMS experiments. The most recent results are discussed in this review.

Déliot, Frédéric; Hadley, Nicholas; Parke, Stephen; Schwarz, Tom

2014-10-01

198

Alaska tops in oil reserves  

SciTech Connect

Alaska ranks second to Texas in daily oil production, putting out 1.6 million barrels/day. Alaska stands at the top for oil reserves, with Texas second, and California third. Prudhoe Bay is at the top with reserves of 7819 billion barrels. Alaska is exploring the icy waters of the Beaufort Sea for new giant fields. Eight exploratory wells are on slate for winter's drilling season. (DP)

Not Available

1982-02-01

199

FSP Index Top Performing Schools http://www.academicanalytics.com/TopSchools/TopSchools.aspx 1 of 3 2/12/2008 5:13 PM  

E-print Network

FSP Index Top Performing Schools http://www.academicanalytics.com/TopSchools/TopSchools.aspx 1 of 3 University of Iowa Brown University #12;FSP Index Top Performing Schools http://www.academicanalytics.com/TopSchools/TopSchools.aspx Graduate School #12;FSP Index Top Performing Schools http://www.academicanalytics.com/TopSchools/TopSchools.aspx

Tesanovic, Zlatko

200

Uncovering the single top: observation of electroweak top quark production  

SciTech Connect

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.

Benitez, Jorge Armando; /Michigan State U.

2009-08-01

201

Corrosion protection of surfaces by nanocomposite and urethane top coatings  

Microsoft Academic Search

In the present study, nanosized silica particles (~100 nm) were incorporated into epoxy polymers, and then sprayed on molybdenum treated Al coupons (2024-T3) by a nozzle spray unit at different thicknesses. A urethane top coating (1 mil) was also applied on some of the initially coated surfaces. The main purpose of the SiO2 and urethane was to absorb\\/block unwanted ions\\/molecules

Ramazan Asmatulu; Richard O. Claus; J. B. Mecham; S. G. Corcoran

2005-01-01

202

Design, Activity, and 2.8 overset{circ}{A} Crystal Structure of a C_2 Symmetric Inhibitor Complexed to HIV-1 Protease  

NASA Astrophysics Data System (ADS)

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 to degradative enzymes. The 2.8 angstrom crystal structure of the inhibitor-enzyme complex demonstrated that the inhibitor binds to the enzyme in a highly symmetric fashion.

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

1990-08-01

203

Engineering Statistics From "Engineering Statistics" , Top &  

E-print Network

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

Kovintavewat, Piya

204

High power terahertz quantum cascade lasers with symmetric wafer bonded active regions  

NASA Astrophysics Data System (ADS)

We increased the active region/waveguide thickness of terahertz quantum cascade lasers with semi-insulating surface plasmon waveguides by stacking two symmetric active regions on top of each other, via a direct wafer bonding technique. In this way, we enhance the generated optical power in the cavity and the mode confinement. We achieved 470 mW peak output power in pulsed mode from a single facet at a heat sink temperature of 5 K and a maximum operation temperature of 122 K. Furthermore, the devices show a broad band emission spectrum over a range of 420 GHz, centered around 3.9 THz.

Brandstetter, Martin; Deutsch, Christoph; Krall, Michael; Detz, Hermann; MacFarland, Donald C.; Zederbauer, Tobias; Andrews, Aaron M.; Schrenk, Werner; Strasser, Gottfried; Unterrainer, Karl

2013-10-01

205

PT-symmetric representations of fermionic algebras  

SciTech Connect

A recent paper by Jones-Smith and Mathur, Phys. Rev. A 82, 042101 (2010) extends PT-symmetric quantum mechanics from bosonic systems (systems for which T{sup 2}=1) to fermionic systems (systems for which T{sup 2}=-1). The current paper shows how the formalism developed by Jones-Smith and Mathur can be used to construct PT-symmetric matrix representations for operator algebras of the form {eta}{sup 2}=0, {eta}{sup 2}=0, {eta}{eta}+{eta}{eta}={alpha}1, where {eta}={eta}{sup PT}=PT{eta}T{sup -1}P{sup -1}. It is easy to construct matrix representations for the Grassmann algebra ({alpha}=0). However, one can only construct matrix representations for the fermionic operator algebra ({alpha}{ne}0) if {alpha}=-1; a matrix representation does not exist for the conventional value {alpha}=1.

Bender, Carl M. [Physics Department, Washington University, St. Louis, Missouri 63130 (United States); Klevansky, S. P. [Institut fuer Theoretische Physik, Universitaet Heidelberg, Philosophenweg 19, D-69120 Heidelberg (Germany)

2011-08-15

206

Spherically symmetric random walks in noninteger dimension  

SciTech Connect

A previous article proposed a new kind of random walk on a spherically symmetric lattice in arbitrary noninteger dimension [ital D]. Such a lattice avoids the problems associated with a hypercubic lattice in noninteger dimension. This article examines the nature of spherically symmetric random walks in detail. A large-time asymptotic analysis of these random walks is performed and the results are used to determine the Hausdorff dimension of the process. Exact results are obtained in terms of Hurwitz functions (incomplete zeta functions) for the probability of a walker going from one region of the spherical lattice to another. Finally, it is shown that the probability that the paths of [ital K] independent random walkers will intersect vanishes in the continuum limit if [ital D][gt]2[ital K]/([ital K][minus]1).

Bender, C.M. (Department of Physics, Washington University, St. Louis, Missouri 63130-4899 (United States)); Boettcher, S. (Department of Physics, Brookhaven National Laboratory, Upton, New York 11973 (United States)); Moshe, M. (Department of Physics, Technion Israel Institute of Technology, Haifa 32000 (Israel))

1994-09-01

207

Binary switching in a 'symmetric' potential landscape  

PubMed Central

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

Roy, Kuntal; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha

2013-01-01

208

Parity-time-symmetric plasmonic metamaterials  

NASA Astrophysics Data System (ADS)

We theoretically investigate the optical properties of parity-time (PT)-symmetric three-dimensional metamaterials composed of strongly coupled planar plasmonic waveguides. By tuning the loss-gain balance, we show how the initially isotropic material becomes both asymmetric and unidirectional. Investigation of the band structure near the material's exceptional point reveals several interesting optical properties, including double negative refraction, Bloch power oscillations, unidirectional invisibility, and reflection and transmission coefficients that are simultaneously equal to or greater than unity. The highly tunable optical dispersion of PT-symmetric metamaterials provides a foundation for designing an unconventional class of three-dimensional bulk synthetic media, with applications ranging from lossless subdiffraction-limited optical lenses to nonreciprocal nanophotonic devices.

Alaeian, Hadiseh; Dionne, Jennifer A.

2014-03-01

209

PT symmetric Aubry-Andre model  

NASA Astrophysics Data System (ADS)

PT symmetric Aubry-Andre model describes an array of N coupled optical waveguides with position-dependent gain and loss. We show that the reality of the spectrum depends sensitively on the degree of quasi-periodicity for small number of lattice sites. We obtain the Hofstadter butterfly spectrum and discuss the existence of the phase transition from extended to localized states. We show that rapidly changing periodical gain/loss materials almost conserve the total intensity.

Yuce, C.

2014-06-01

210

Expansion-free Cylindrically Symmetric Models  

E-print Network

This paper investigates cylindrically symmetric distribution of an-isotropic fluid under the expansion-free condition, which requires the existence of vacuum cavity within the fluid distribution. We have discussed two family of solutions which further provide two exact models in each family. Some of these solutions satisfy Darmois junction condition while some show the presence of thin shell on both boundary surfaces. We also formulate a relation between the Weyl tensor and energy density.

M. Sharif; Z. Yousaf

2013-10-30

211

Numerical analysis of the symmetric methods  

Microsoft Academic Search

Aimed at the initial value problem of the particular second-order ordinary differential equations,y?=f(x, y), the symmetric methods (Quinlan and Tremaine, 1990) and our methods (Xu and Zhang, 1994) have been compared in detail by integrating the artificial earth satellite orbits in this paper. In the end, we point out clearly that the integral accuracy of numerical integration of the satellite

Ji-Hong Xu; A-Li Zhang

1995-01-01

212

Highly symmetric travelling waves in pipe flow  

Microsoft Academic Search

The recent theoretical discovery of finite-amplitude travelling waves in pipe flow has re-ignited interest in the transitional phenomena that Osborne Reynolds studied 125 years ago. Despite all being unstable, these waves are providing fresh insight into the flow dynamics. Here we describe two new classes of highly-symmetric travelling waves (possessing rotational, shift-&-reflect and mirror symmetries) and report a new family

Chris C. T. Pringle; Yohann Duguet; Rich R. Kerswell

2009-01-01

213

Symmetric correlations as seen at RHIC  

E-print Network

We analyze the forward-backward multiplicity correlation coefficient as measured by STAR. We show that in the most central Au+Au collisions bins located symmetrically around \\eta = 0 with large separation in pseudorapidity are more strongly correlated than bins located asymmetrically with smaller separation. In proton-proton collisions the opposite effect is observed. It suggests a qualitatively different behavior of the two-particle correlation as a function of pseudorapidity sum in p+p and Au+Au collisions.

Adam Bzdak

2011-08-03

214

Solitons in PT-symmetric nonlinear lattices  

SciTech Connect

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.

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

215

Wave equation on spherically symmetric Lorentzian metrics  

SciTech Connect

Wave equation on a general spherically symmetric spacetime metric is constructed. Noether symmetries of the equation in terms of explicit functions of {theta} and {phi} are derived subject to certain differential constraints. By restricting the metric to flat Friedman case the Noether symmetries of the wave equation are presented. Invertible transformations are constructed from a specific subalgebra of these Noether symmetries to convert the wave equation with variable coefficients to the one with constant coefficients.

Bokhari, Ashfaque H.; Al-Dweik, Ahmad Y.; Zaman, F. D. [Department of Mathematics, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Kara, A. H. [School of Mathematics, University of the Witwatersrand, Johannesburg (South Africa); Karim, M. [Department of Physics, St. John Fisher College, Rochester, New York 14618 (United States)

2011-06-15

216

Time-symmetrized quantum theory: A critique  

NASA Astrophysics Data System (ADS)

This dissertation considers various claims which have been made by proponents of time-symmetrized quantum theory (TSQT), focusing in particular on the work of Lev Vaidman, who has been the strongest advocate in recent years. These claims attribute ``elements of reality,'' corresponding to dispersion-free values of noncommuting observables, to pre- and post-selected quantum systems via the Aharonov-Bermann-Lebowitz (ABL) rule of time-symmetrized quantum theory. The novelty of the TSQT approach is the assertion that more information can be gained about a system in a symmetric time interval bounded by given past and future measurement outcomes than via the usual, time-asymmetric Born rule requiring that only a pre-selection outcome be given. Such claims, if true, would be valuable for a realist interpretation of quantum theory. The value would lie in the possibility of quantum states with dispersion-free values for noncommuting observables, provided such states are defined time-symmetrically through the use of two-state vectors according to the prescription of TSQT. Thus the basic question to be addressed is: Does TSQT shed any new light on the debate concerning the adequacy of realist interpretations of quantum theory? Answering this question requires a careful evaluation of the counterfactual usage of the ABL rule, which is the only way to obtain the inferences about dispersion-free values. The analysis shows that the counterfactual usage is, in general, invalid, and therefore the program advocated by Vaidman, Aharonov, and others fails to provide new insights into, or support for, a realist interpretation of quantum theory.

Kastner, Ruth Elinor

217

Random walks on highly symmetric graphs  

Microsoft Academic Search

We consider uniform random walks on finite graphs withn nodes. When the hitting times are symmetric, the expected covering time is at least 1\\/2n logn-O(n log logn) uniformly over all such graphs. We also obtain bounds for the covering times in terms of the eigenvalues of the transition matrix of the Markov chain. For distance-regular graphs, a general lower bound

Luc Devroye; Amine Sbihi

1990-01-01

218

Geometry of PT-symmetric quantum mechanics  

Microsoft Academic Search

Recently, much research has been carried out on Hamiltonians that are not\\u000aHermitian but are symmetric under space-time reflection, that is, Hamiltonians\\u000athat exhibit PT symmetry. Investigations of the Sturm-Liouville eigenvalue\\u000aproblem associated with such Hamiltonians have shown that in many cases the\\u000aentire energy spectrum is real and positive and that the eigenfunctions form an\\u000aorthogonal and complete basis.

Carl M. Bender; Dorje C. Brody; Bernhard K. Meister

2007-01-01

219

Planar Poincaré domains: Geometry and Steiner symmetrization  

Microsoft Academic Search

We determine geometric necessary and sufficient conditions on a class of strip-like planar domains in order for them to satisfy\\u000a the Poincaré inequality with exponentp, where 1?pp and generalizes the quasi-hyperbolic metric in the casep=2. As an application, we show that the Poincaré inequality is preserved under Steiner symmetrization of these domains but\\u000a not in general.\\u000a \\u000a We also show that

Wayne Smith; Alexander Stanoyevitch; David A. Stegenga

1995-01-01

220

Symmetric states: local unitary equivalence via stabilizers  

E-print Network

We classify local unitary equivalence classes of symmetric states via a classification of their local unitary stabilizer subgroups. For states whose local unitary stabilizer groups have a positive number of continuous degrees of freedom, the classification is exhaustive. We show that local unitary stabilizer groups with no continuous degrees of freedom are isomorphic to finite subgroups of the rotation group SO(3), and give examples of states with discrete stabilizers.

Curt D. Cenci; David W. Lyons; Laura M. Snyder; Scott N. Walck

2010-07-22

221

Magnetic control of a meta-molecule.  

PubMed

Metamaterials offer the prospect of new science and applications. They have been designed by shaping or changing the material of the individual meta-molecules to achieve properties not naturally attainable. Composite meta-molecules incorporating a magnetic component offer new opportunities. In this work we report on the interaction between a non-magnetic split ring resonator (SRR) and a thin film of yttrium iron garnet (YIG). Strong hybridized resonances are observed. While the SRR is characterized by a magnetic and electric resonance, in practice, it is found that the YIG couples strongly to this symmetric (electric) mode of the SRR. It is also demonstrated that the anti-crossing region provides fertile ground for the creation of elementary excitations such as backward volume magnetostatic waves. PMID:23389127

Stenning, Gavin B G; Bowden, Graham J; Maple, Lewis C; Gregory, Simon A; Sposito, Alberto; Eason, Robert W; Zheludev, Nikolay I; de Groot, Peter A J

2013-01-28

222

Symmetric multilayer megampere X-pinch  

SciTech Connect

Raising the power of X-ray emission from an X-pinch by increasing the pinch current to the megampere level requires the corresponding increase in the initial linear mass of the load. This can be achieved by increasing either the number of wires or their diameter. In both cases, special measures should be undertaken to prevent the formation of a complicated configuration with an uncontrolled spatial structure in the region of wire crossing, because such a structure breaks the symmetry of the neck formed in the crossing region, destabilizes plasma formation, and degrades X-ray generation. To improve the symmetry of the wire crossing region, X-pinch configurations with a regular multilayer arrangement of wires in this region were proposed and implemented. The results of experiments with various symmetric X-pinch configurations on the COBRA facility at currents of {approx}1MA are presented. It is shown that an X-pinch with a symmetric crossing region consisting of several layers of wires made of different materials can be successfully used in megampere facilities. The most efficient combinations of wires in symmetric multilayer X-pinches are found in which only one hot spot forms and that are characterized by a high and stable soft X-ray yield.

Shelkovenko, T. A.; Pikuz, S. A. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation); McBride, R. D. [Sandia National Laboratories (United States); Knapp, P. F.; Wilhelm, G. [Cornell University (United States); Sinars, D. B. [Sandia National Laboratories (United States); Hammer, D. A. [Cornell University (United States); Orlov, N. Yu. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

2010-01-15

223

Symmetric multilayer megampere X-pinch  

NASA Astrophysics Data System (ADS)

Raising the power of X-ray emission from an X-pinch by increasing the pinch current to the megampere level requires the corresponding increase in the initial linear mass of the load. This can be achieved by increasing either the number of wires or their diameter. In both cases, special measures should be undertaken to prevent the formation of a complicated configuration with an uncontrolled spatial structure in the region of wire crossing, because such a structure breaks the symmetry of the neck formed in the crossing region, destabilizes plasma formation, and degrades X-ray generation. To improve the symmetry of the wire crossing region, X-pinch configurations with a regular multilayer arrangement of wires in this region were proposed and implemented. The results of experiments with various symmetric X-pinch configurations on the COBRA facility at currents of ˜1MA are presented. It is shown that an X-pinch with a symmetric crossing region consisting of several layers of wires made of different materials can be successfully used in megampere facilities. The most efficient combinations of wires in symmetric multilayer X-pinches are found in which only one hot spot forms and that are characterized by a high and stable soft X-ray yield.

Shelkovenko, T. A.; Pikuz, S. A.; McBride, R. D.; Knapp, P. F.; Wilhelm, G.; Sinars, D. B.; Hammer, D. A.; Orlov, N. Yu.

2010-01-01

224

Pyramid diffraction in parity-time-symmetric optical lattices  

E-print Network

-symmetric systems can be realized by employing symmetric index guiding and an antisym- metric gain in the nonlinear regime for both focusing and defocusing nonlinearities. © 2013 Optical Society of America OCIS.38.001933 Parity-time (PT )-symmetric wave systems have the un- intuitive property that their linear

Yang, Jianke

225

Properties of the top quark  

E-print Network

Recent measurements of top-quark properties at the LHC and the Tevatron are presented. Most recent measurements of the top quark mass have been carried out by CMS using $19.7/$fb of $\\sqrt{s} = 8$ TeV data including the study of the dependence on event kinematics. ATLAS uses the full Run I data at $\\sqrt{s} = 7$ TeV for a "3D" measurement that significantly reduces systematic uncertainties. D0 employs the full Run II data using the matrix element method to measure the top quark mass with significantly reduced systematic uncertainties. Many different measurements of the top quark exist to date and the most precise ones per decay channel per experiment have been combined into the first world combination with a relative precision of 0.44\\%. Latest updates of measurements of production asymmetries include the measurement of the \\ttbar production asymmetry by D0 employing the full Run II data set, by CMS and ATLAS (including the polarization of the top quark) employing both the full data set at $\\sqrt{s} = 7$ TeV....

Jung, A W

2014-01-01

226

Study of anomalous top quark flavor-changing neutral current interactions via the tW channel of single-top-quark production  

SciTech Connect

The potential of the LHC for investigation of anomalous top quark interactions with gluon (tug,tcg) through the production of tW channel of single top quarks is studied. In the standard model, the single top quarks in the tW-channel mode are charge symmetric, meaning that {sigma}(pp{yields}t+W{sup -})={sigma}(pp{yields}t+W{sup +}). However, the presence of anomalous flavor-changing neutral current (FCNC) couplings leads to charge asymmetry. In this paper, a method is proposed in which this charge asymmetry may be used to constrain anomalous FCNC couplings. The strength of resulting constraints is estimated for the LHC for the center of mass energies of 7 and 14 TeV.

Etesami, S. M. [Physics Department, Isfahan University of Technology (IUT), Isfahan (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Mohammadi Najafabadi, M. [School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

2010-06-01

227

Exploring Rotation-Vibration Coupling in Highly Fluxional Molecules Using Surface Hopping Diffusion Monte Carlo  

NASA Astrophysics Data System (ADS)

Diffusion Monte Carlo (DMC) has widely been shown to be a powerful technique for studying ro-vibrational states of highly fluxional molecules and clusters. An extension of DMC to multiple potential energy surfaces (PESs) based on the Tully surface hopping approach has previously been developed by our group. Here, we report an application of this approach to the calculation of rotationally excited states of systems with pronounced rotation-vibration coupling and large-amplitude, zero-point vibrational motion. More specifically, for a chosen value of J, each walker in the DMC ensemble is expanded in a symmetric top basis. The expansion coefficients are updated each time-step based on the action of the rigid-rotor asymmetric top Hamiltonian. This Hamiltonian is constructed using the inverse moment of inertia tensor evaluated in the Eckart frame at the walker's position in configuration space. Each walker is then localized onto a single, K-dependent effective PES, and the effective potential energy associated with the walker's position on that surface determines the evolution of its weight in the DMC ensemble. Preliminary results of the application of this methodology to model systems such as H_3^+ and H_2D^+ will be discussed as well as its prospect for accurately evaluating ro-vibrational states of systems like CH_5^+. Finally, a comparison of this technique with our previously developed fixed-node DMC approach for the evaluation of ro-vibrational energies and wave functions will be presented. J. C. Tully, J. Chem. Phys. 93, 1061 (1990). A.B. McCoy, Chem. Phys. Lett. 321, 71 (2000). A. S. Petit, B. A. Wellen, and A. B. McCoy, J. Chem. Phys. 136, 074101 (2012).

Petit, Andrew S.; McCoy, Anne B.

2012-06-01

228

Light Top Squark in Precision Top Quark Sample  

E-print Network

The uncertainty of $t\\bar{t}$ production cross section measurement at LHC is at a-few-percent level which still allows the stop pair production $\\tilde{t}\\tilde{t}^{*}$ with identical final states $2b+\\ell+nj+{E}_{T}$. In this paper, we attempt to use the existing measurement of $W$-polarization in top quark decay to improve the distinction between stop and top quark states. We apply the ATLAS $\\chi^2$ method of $W$-polarization measurement in semi-leptonic $t\\bar{t}$ final state to semi-leptonic stop pair samples and study its prediction. We find that the faked top events from stop mostly contribute to the left-handed polarized $W$ due to the reconstruction. The benchmark point with maximal contribution to top events only changes $F_{L}$ by 1%. After comparing with the current experiments, we conclude that the current measurement of $W$-polarization in $t$ decay cannot exclude the light stop scenario.

Xue-Qian Li; Zong-Guo Si; Kai Wang; Liucheng Wang; Liangliang Zhang; Guohuai Zhu

2013-11-27

229

Top Quark Spin Correlations - Theory  

SciTech Connect

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].

Parke, Stephen J.; /Fermilab

2012-02-01

230

Top Mass Measurements at the Tevatron  

SciTech Connect

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 m{sub top} = 172.6 {+-} 1.4 GeV.

Wang, M.H.L.S.; /Fermilab

2009-04-01

231

Top quark physics in hadron collisions  

Microsoft Academic Search

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 (SM) of particle physics. In addition, the top quark mass is

Wolfgang Wagner

2005-01-01

232

Collision-induced absorption in a highly symmetric molecule - SF6  

Microsoft Academic Search

The far-infrared absorption spectra of gaseous (298 K) and liquid (273 K, 233 K) SF6 obtained by Rosenberg and Birnbaum [1] are analysed in terms of recent theoretical developments. Analysis of the band shape in the gas and liquid phases indicates that hexadecapole-induced absorption accounts only for the low frequency portion of the collision-induced band. The major part of the

George Birnbaum; Herbert Sutter

1981-01-01

233

Matrix isolation ESR spectroscopy and magnetic anisotropy of D{sub 3h} symmetric septet trinitrenes  

SciTech Connect

The fine-structure (FS) parameters D of a series of D{sub 3h} symmetric septet trinitrenes were analyzed theoretically using density functional theory (DFT) calculations and compared with the experimental D values derived from ESR spectra. ESR studies show that D{sub 3h} symmetric septet 1,3,5-trichloro-2,4,6-trinitrenobenzene with D=-0.0957 cm{sup -1} and E= 0 cm{sup -1} is the major paramagnetic product of the photolysis of 1,3,5-triazido-2,4,6-trichlorobenzene in solid argon matrices at 15 K. Trinitrenes of this type display in the powder X-band ESR spectra intense Z{sub 1}-transition at very low magnetic fields, the position of which allows one to precisely calculate the parameter D of such molecules. Thus, our revision of the FS parameters of well-known 1,3,5-tricyano-2,4,6-trinitrenobenzene [E. Wasserman, K. Schueller, and W. A. Yager, Chem. Phys. Lett. 2, 259 (1968)] shows that this trinitrene has Double-Vertical-Line D Double-Vertical-Line = 0.092 cm{sup -1} and E= 0 cm{sup -1}. DFT calculations reveal that, unlike C{sub 2v} symmetric septet trinitrenes, D{sub 3h} symmetric trinitrenes have the same orientations of the spin-spin coupling tensor D-caret{sub SS} and the spin-orbit coupling tensor D-caret{sub SOC} and, as a result, have negative signs for both the D{sub SS} and D{sub SOC} values. The negative magnetic anisotropy of septet 2,4,6-trinitrenobenzenes is considerably strengthened on introduction of heavy atoms in the molecules, owing to an increase in contributions of various excitation states to the D{sub SOC} term.

Misochko, Eugenii Ya.; Akimov, Alexander V.; Masitov, Artem A.; Korchagin, Denis V.; Aldoshin, Sergei M.; Chapyshev, Sergei V. [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432 (Russian Federation)

2013-05-28

234

Patterns of energy levels and spectra for polyatomic molecules  

SciTech Connect

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.

Harter, W.G.

1983-01-01

235

Solvatochromism of anthraquinone and symmetrical dihydroxy derivatives. Local interactions  

NASA Astrophysics Data System (ADS)

The solvent effects on the electronic absorption spectra of 9,10-anthraquinone (AQ) and its symmetric dihydroxy derivatives namely 1,5-dihydroxyanthraquinone (1,5-DHAQ) and 2,6-dihydroxyanthraquinone (2,6-DHAQ) have been studied in pure solvents and some binary solvent mixtures. The frequencies of the absorption for AQ and 2,6-DHAQ are quite solvent sensitive while those for 1,5-DHAQ are not. Due to the intramolecular hydrogen bond between the C?O and OH groups, no influence of solvent hydrogen bond acceptors is observed in 1,5-DHAQ. This hydrogen bond gives a stable six member cycle which is not broken even by the strongest hydrogen bond acceptor solvents used in this work, such as DMSO and DMF. The Taft and Kamlet's solvatochromic comparison method was applied for AQ and 2,6-DHAQ. Aromatic solvents and aliphatic amines were not included in the correlations since they strongly deviate suggesting another type of interactions. All the ??? * bands of AQ and 2,6-DHAQ show strong influence of ? * despite the fact that their dipole moment is zero. Although it would be reasonable to expect that in the absence of a solute dipole moment there is not significant orientation of solvent molecules around the solute molecules, in this case dipolar interactions between solute and solvent due to local effects might be expected. AQ may be considered as formed by two carbonyl groups weakly interacting with the benzene rings; that means that the carbonyl group can behave as an isolated dipole and independently of the other. To detect possible specific interactions between the AQ and aliphatic amines and aromatic hydrocarbons, preferential solvation in mixed solvent was investigated. It is concluded that EDA interactions are important in the solvation of AQ with these compounds as solvents.

Reta, Mario R.; Cartana, Rosa; Anunziata, Jorge D.; Silber, Juana J.

1993-07-01

236

Top quark mass and kinematics  

SciTech Connect

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.

Barberis, Emanuela; /Northeastern U.

2006-05-01

237

The Top STEM Degree Producers  

ERIC Educational Resources Information Center

This article presents a list of the top Science, Technology, Engineering, and Mathematics (STEM) degree producers in the U.S. This list is broken down into seven categories: (1) Total Minority Research/Scholarship and Other Doctoral: Mathematics and Statistics; (2) Total Minority Bachelors: Biological and Biomedical Sciences; (3) Total Minority…

Diverse: Issues in Higher Education, 2012

2012-01-01

238

Prospects for top at CDF  

SciTech Connect

During the next two years, the Fermilab Tavatron is expected to deliver approximately 100pb{sup {minus}1} of integrated luminosity. We describe improvements to the CDF detector since the 1988--89 collider run and discuss the prospects for the discovery of the top quark during the 1992--93 collider runs.

Gerdes, D. (Chicago Univ., IL (United States))

1992-06-03

239

Ejs Torque Free Top Model  

NSDL National Science Digital Library

The Ejs Torque Free Top model displays the motion of a top, in both the space frame and body frame, with no net toque applied. The top has an initial angular speed in the x, y, and z directions. The moments of inertia in each direction, and the initial angular positions and angular speeds can be changed via textboxes. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. Ejs Torque Free Top model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_ehu_rigid_bodies_free.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models for rigid body dynamics are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Aguirregabiria, Juan

2008-08-18

240

Kowalevski top in quantum mechanics  

SciTech Connect

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.

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

2013-09-15

241

Conservation: Top predators and biodiversity  

Microsoft Academic Search

The charisma of top vertebrate predators is often used by conservationists as a lever for financial support, to raise environmental awareness and in planning protected areas - a strategy that has been criticized. Here we use information collected from five raptor species that differ widely in their diet and habitat associations to show that sites occupied by these predators are

Fabrizio Sergio; Ian Newton; Luigi Marchesi

2005-01-01

242

Race to Top Applications Scrutinized  

ERIC Educational Resources Information Center

As peer reviewers for the U.S. Department of Education begin to comb through the thousands of pages of applications for $4 billion in federal Race to the Top Fund grants, they'll be under pressure to determine which are most worthy of funding: those that promise the most, or those with the best chance of delivering. In a competition whose criteria…

Sawchuk, Stephen; Maxwell, Lesli A.

2010-01-01

243

The 2003 Training Top 100.  

ERIC Educational Resources Information Center

Identifies the top 100 U.S. companies in terms of the amount spent on training and development, the number of hours of training per employee, percentage of payroll spent on training, and tuition allotment per employee. Describes best practices in succession planning and leadership development, mentoring, and job shadowing and provides a detailed…

Galvin, Tammy

2003-01-01

244

"Top School Problems" Are Myths.  

ERIC Educational Resources Information Center

A well-known "study" comparing the top school problems of 1940 (talking and gum chewing) with those of 1987 (drug abuse, pregnancy, and violence) is nonexistent. In 1940, 49 percent of all youth did not finish high school, 37,000 teenagers died from violence or disease, and 335,000 teens gave birth. Educators should discount pastoral memories and…

Males, Mike

1992-01-01

245

Top Jets at the LHC  

SciTech Connect

We investigatethe reconstruction of high pT hadronically-decaying top quarksat the Large Hadron Collider. One of the main challenges in identifying energetictop quarks is that the decay products become increasingly collimated. This reducesthe efficacy of conventional reconstruction methods that exploit the topology of thetop quark decay chain. We focus on the cases where the decay products of the topquark are reconstructed as a single jet, a"top-jet." The most basic"top-tag" methodbased on jet mass measurement is considered in detail. To analyze the feasibility ofthe top-tagging method, both theoretical and experimental aspects of the large QCDjet background contribution are examined. Based on a factorization approach, wederive a simple analytic approximation for the shape of the QCD jet mass spectrum.We observe very good agreement with the Monte Carlo simulation. We consider high pT tt bar production in the Standard Model as an example, and show that our theoretical QCD jet mass distributions can efficiently characterize the background via sideband analyses. We show that with 25 fb-1 of data, our approach allows us to resolve top-jets with pT _> 1 TeV, from the QCD background, and about 1.5 TeV top-jets with 100 fb-1, without relying on b-tagging. To further improve the significancewe consider jet shapes (recently analyzed in 0807.0234 [hep-ph]), which resolve thesubstructure of energy flow inside cone jets. A method of measuring the top quarkpolarization by using the transverse momentum of the bottom quark is also presented.The main advantages of our approach are: (i) the mass distributions are driven byfirst principle calculations, instead of relying solely on Monte Carlo simulation; (ii) for high pT jets (pT _> 1 TeV), IR-safe jet shape variables are robust against detectorresolution effects. Our analysis can be applied to other boosted massive particlessuch as the electroweak gauge bosons and the Higgs.

Almeida, L.G.; Lee, S.J.; Perez, G.; Sung, I.; Virzi, J.

2008-10-06

246

Expanding symmetric multiprocessor capability through gang scheduling  

SciTech Connect

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.

Jette, M.A.

1998-03-01

247

Entanglement and symmetry in permutation symmetric states  

E-print Network

We investigate the relationship between multipartite entanglement and symmetry, focusing on permutation symmetric states. We use the Majorana representation, where these states correspond to points on a sphere. Symmetry of the representation under rotation is equivalent to symmetry of the states under products of local unitaries. The geometric measure of entanglement is thus phrased entirely as a geometric optimisation, and a condition for the equivalence of entanglement measures written in terms of point symmetries. Finally we see that different symmetries of the states correspond to different types of entanglement with respect to SLOCC interconvertibility.

Damian J. H. Markham

2010-01-03

248

Matter Collineations of Plane Symmetric Spacetimes  

E-print Network

This paper is devoted to the study of matter collineations of plane symmetric spacetimes (for a particular class of spacetimes) when the energy-momentum tensor is non-degenerate. There exists many interesting cases where we obtain proper matter collineations. The matter collineations in these cases are {\\it four}, \\emph{five}, {\\it six}, \\emph{seven} and {\\it ten} with some constraints on the energy-momentum tensor. We have solved some of these constraints to obtain solutions of the Einstein field equations.

M. Sharif; Nousheen Ilyas

2008-09-09

249

Chaos in symmetric phase oscillator networks.  

PubMed

Phase-coupled oscillators serve as paradigmatic models of networks of weakly interacting oscillatory units in physics and biology. The order parameter which quantifies synchronization so far has been found to be chaotic only in systems with inhomogeneities. Here we show that even symmetric systems of identical oscillators may not only exhibit chaotic dynamics, but also chaotically fluctuating order parameters. Our findings imply that neither inhomogeneities nor amplitude variations are necessary to obtain chaos; i.e., nonlinear interactions of phases give rise to the necessary instabilities. PMID:22243002

Bick, Christian; Timme, Marc; Paulikat, Danilo; Rathlev, Dirk; Ashwin, Peter

2011-12-01

250

Quantum exchange interaction of spherically symmetric plasmoids  

E-print Network

We study nano-sized spherically symmetric plasma structures which are radial nonlinear oscillations of electrons in plasma. The effective interaction of these plasmoids via quantum exchange forces between ions is described. We calculate the energy of this interaction for the realistic case of an atmospheric plasma. The conditions when the exchange interaction is attractive are examined and it is shown that separate plasmoids can form a single object. The application of our results to the theoretical description of stable atmospheric plasma structures is considered.

Dvornikov, Maxim

2011-01-01

251

Single mode PT symmetric large area lasers  

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

252

Communities and classes in symmetric fractals  

E-print Network

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 analysed 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.

Krawczyk, M J

2014-01-01

253

Top quark production at the Tevatron  

SciTech Connect

The Fermilab Tevatron has, until recently, been the only accelerator with sufficient energy to produce top quarks. The CDF and D0 experiments have collected large samples of top quarks. We report on recent top quark production measurements of the single top and t{bar t} production cross sections, as well as studies of the t{bar t} invariant mass distribution and a search for highly boosted top quarks.

Varnes, Erich W.; /Arizona U.

2010-09-01

254

Technologies for nanofluidic systems: top-down vs. bottom-up - a review  

Microsoft Academic Search

This paper gives an overview of the most commonly used techniques for nanostructuring and nanochannel fabrication employed in nanofluidics. They are divided into two large categories: top-down and bottom-up methods. Top-down methods are based on patterning on large scale while reducing the lateral dimensions to the nanoscale. Bottom-up methods arrange atoms and molecules in nanostructures. Here, we review the advantages

D. Mijatovic; J. C. T. Eijkel; A. van den Berg

2005-01-01

255

Nanophotonics and Single Molecules  

Microsoft Academic Search

Single emitting molecules are currently providing a new window into nanoscale systems ranging from biology to materials science.\\u000a The amount of information that can be extracted from each single molecule depends upon the specific photophysical properties\\u000a of the fluorophore and how these properties are affected by the nearby environment. For this reason, it is necessary to develop\\u000a single-molecule emitters with

W. E. Moerner; P. James Schuck; David P. Fromm; Anika Kinkhabwala; Samuel J. Lord; Stefanie Y. Nishimura; Katherine A. Willets; Arvind Sundaramurthy; Gordon Kino; Meng He; Zhikuan Lu; Robert J. Twieg

256

Properties of the Top Quark  

SciTech Connect

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.

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

2009-08-01

257

A single-molecule diode  

NASA Astrophysics Data System (ADS)

We have designed and synthesized a molecular rod that consists of two weakly coupled electronic ? -systems with mutually shifted energy levels. The asymmetry thus implied manifests itself in a current-voltage characteristic with pronounced dependence on the sign of the bias voltage, which makes the molecule a prototype for a molecular diode. The individual molecules were immobilized by sulfur-gold bonds between both electrodes of a mechanically controlled break junction, and their electronic transport properties have been investigated. The results indeed show diode-like current-voltage characteristics. In contrast to that, control experiments with symmetric molecular rods consisting of two identical ? -systems did not show significant asymmetries in the transport properties. To investigate the underlying transport mechanism, phenomenological arguments are combined with calculations based on density functional theory. The theoretical analysis suggests that the bias dependence of the polarizability of the molecule feeds back into the current leading to an asymmetric shape of the current-voltage characteristics, similar to the phenomena in a semiconductor diode. Author contributions: F.E., H.B.W., and M.M. designed research; M.E., R.O., M.K., M.F., F.E., H.B.W., and M.M. performed research; M.E., R.O., M.K., M.F., C.v.H., F.W., F.E., H.B.W., and M.M. contributed new reagents/analytic tools; M.E., R.O., M.K., C.v.H., F.E., H.B.W., and M.M. analyzed data; and F.E., H.B.W., and M.M. wrote the paper.This paper was submitted directly (Track II) to the PNAS office.Abbreviations: A, acceptor; D, donor; MCB, mechanically controlled break junction.Data deposition: The atomic coordinates have been deposited in the Cambridge Structural Database, Cambridge Crystallographic Data Centre, Cambridge CB2 1EZ, United Kingdom (CSD reference no. 241632).

Elbing, Mark; Ochs, Rolf; Koentopp, Max; Fischer, Matthias; von Hänisch, Carsten; Weigend, Florian; Evers, Ferdinand; Weber, Heiko B.; Mayor, Marcel

2005-06-01

258

Rotationally symmetric operators for surface interpolation  

SciTech Connect

The use of rotationally symmetric operators in vision is reviewed and conditions for rotational symmetry are derived for linear and quadratic forms in the first and second partial directional derivatives of a function f(x,y). Surface interpolation is considered to be the process of computing the most conservative solution consistent with boundary conditions. The 'most conservative' solution is modelled using the calculus of variations to find the minimum function that satisfies a given performance index. To guarantee the existence of a minimum function, Grimson has recently suggested that the performance index should be a seminorm. It is shown that all quadratic forms in the second partial derivatives of the surface satisfy this criterion. The seminorms that are, in addition, rotationally symmetric form a vector space whose basis is the square Laplacian and the quadratic variation. Whereas both seminorms give rise to the same Euler condition in the interior, the quadratic variation offers the tighter constraint at the boundary and is to be preferred for surface interpolation.

Brady, M.; Horn, B.K.P.

1982-01-01

259

Nuclear physics with spherically symmetric supernova models  

E-print Network

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.

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

2007-08-31

260

PT-symmetric sine-Gordon breathers  

NASA Astrophysics Data System (ADS)

In this work, we explore a prototypical example of a genuine continuum breather (i.e., not a standing wave) and the conditions under which it can persist in a PT-symmetric medium. As our model of interest, we will explore the sine-Gordon equation in the presence of a PT-symmetric perturbation. Our main finding is that the breather of the sine-Gordon model will only persist at the interface between gain and loss that PT-symmetry imposes but will not be preserved if centered at the lossy or at the gain side. The latter dynamics is found to be interesting in its own right giving rise to kink–antikink pairs on the gain side and complete decay of the breather on the lossy side. Lastly, the stability of the breathers centered at the interface is studied. As may be anticipated on the basis of their ‘delicate’ existence properties such breathers are found to be destabilized through a Hopf bifurcation in the corresponding Floquet analysis.

Lu, Nan; Kevrekidis, Panayotis G.; Cuevas-Maraver, Jesús

2014-11-01

261

Compressible flow about symmetrical Joukowski profiles  

NASA Technical Reports Server (NTRS)

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.

Kaplan, Carl

1938-01-01

262

Analysis of non-symmetrical flapping airfoils  

NASA Astrophysics Data System (ADS)

Simulations have been done to assess the lift, thrust and propulsive efficiency of different types of non-symmetrical airfoils under different flapping configurations. The variables involved are reduced frequency, Strouhal number, pitch amplitude and phase angle. In order to analyze the variables more efficiently, the design of experiments using the response surface methodology is applied. Results show that both the variables and shape of the airfoil have a profound effect on the lift, thrust, and efficiency. By using non-symmetrical airfoils, average lift coefficient as high as 2.23 can be obtained. The average thrust coefficient and efficiency also reach high values of 2.53 and 0.61, respectively. The lift production is highly dependent on the airfoil’s shape while thrust production is influenced more heavily by the variables. Efficiency falls somewhere in between. Two-factor interactions are found to exist among the variables. This shows that it is not sufficient to analyze each variable individually. Vorticity diagrams are analyzed to explain the results obtained. Overall, the S1020 airfoil is able to provide relatively good efficiency and at the same time generate high thrust and lift force. These results aid in the design of a better ornithopter’s wing.

Tay, W. B.; Lim, K. B.

2009-08-01

263

Local and Global Stability ofLocal and Global Stability of Symmetric HeterogeneouslySymmetric Heterogeneously--  

E-print Network

Symmetric Heterogeneously-- Delayed Control SystemsDelayed Control Systems Yueping Zhang and Dmitri Loguinov Department heterogeneous delay: ­ Each flow has a different RTT equal to time units ­ Metric can be fixed for each flow or changing over time (i.e., random) #12;5 · Not only are real Internet delays heterogeneous, they are also

Loguinov, Dmitri

264

Decay Structure for Symmetric Hyperbolic Systems with Non-Symmetric Relaxation and its Application  

NASA Astrophysics Data System (ADS)

This paper is concerned with the decay structure for linear symmetric hyperbolic systems with relaxation. When the relaxation matrix is symmetric, the dissipative structure of the systems is completely characterized by the Kawashima-Shizuta stability condition formulated in Umeda et al. (Jpn J Appl Math 1:435-457, 1984) and Shizuta and Kawashima (Hokkaido Math J 14:249-275, 1985) and we obtain the asymptotic stability result together with the explicit time-decay rate under that stability condition. However, some physical models which satisfy the stability condition have non-symmetric relaxation term (for example, the Timoshenko system and the Euler-Maxwell system). Moreover, it had been already known that the dissipative structure of such systems is weaker than the standard type and is of the regularity-loss type (see Duan in J Hyperbolic Differ Equ 8:375-413, 2011; Ide et al. in Math Models Meth Appl Sci 18:647-667, 2008; Ide and Kawashima in Math Models Meth Appl Sci 18:1001-1025, 2008; Ueda et al. in SIAM J Math Anal 2012; Ueda and Kawashima in Methods Appl Anal 2012). Therefore our purpose in this paper is to formulate a new structural condition which includes the Kawashima-Shizuta condition, and to analyze the weak dissipative structure for general systems with non-symmetric relaxation.

Ueda, Yoshihiro; Duan, Renjun; Kawashima, Shuichi

2012-07-01

265

Boosted Top Quarks and Jet Structure  

E-print Network

The Large Hadron Collider (LHC) is the first machine that provides high enough energy to produce large numbers of boosted top quarks. The decay products of these top quarks are confined to a cone in the top quark flight direction and can be clustered to a single jet. Top quark reconstruction then amounts to analysing the structure of the jet and looking for subjets that are kinematically compatible with top quark decay. Many techniques have been developed recently to best use these topologies to identify top quarks in a large background of non-top jets. This article reviews the results obtained using LHC data recorded in the years 2010-2012 by the experiments ATLAS and CMS. Studies of Standard Model top quark production and searches for new massive particles that decay to top quarks are presented.

Sebastian Schaetzel

2014-03-20

266

Site-selective hexa-hetero-functionalization of ?-cyclodextrin an archetypical C6-symmetric concave cycle.  

PubMed

Access to Cn (n>4) symmetric cyclic concave molecules with a different function on each of their n subunits is an unmet challenge. The reason lies in the lack of a post-functionalization method whose site selectivity is sufficiently understood, predictable and modulable to access most functionalization patterns. Here we disclose a new site-directing rule for a debenzylation reaction on cyclodextrins that solves this problem and allows the unprecedented access to penta- and ultimately hexa-differentiations of such C6 concave cycles. This achievement opens the access to objects with very high-density information. PMID:25382259

Wang, Bo; Zaborova, Elena; Guieu, Samuel; Petrillo, Marta; Guitet, Maxime; Blériot, Yves; Ménand, Mickaël; Zhang, Yongmin; Sollogoub, Matthieu

2014-01-01

267

Symmetric Resonance Charge Exchange Cross Section Based on Impact Parameter Treatment  

NASA Technical Reports Server (NTRS)

Using a two-state impact parameter approximation, a calculation has been carried out to obtain symmetric resonance charge transfer cross sections between nine ions and their parent atoms or molecules. Calculation is based on a two-dimensional numerical integration. The method is mostly suited for hydrogenic and some closed shell atoms. Good agreement has been obtained with the results of laboratory measurements for the ion-atom pairs H+-H, He+-He, and Ar+-Ar. Several approximations in a similar published calculation have been eliminated.

Omidvar, Kazem; Murphy, Kendrah; Atlas, Robert (Technical Monitor)

2002-01-01

268

Maximum tunneling velocities in symmetric double well potentials  

NASA Astrophysics Data System (ADS)

We consider coherent tunneling of one-dimensional model systems in non-cyclic or cyclic symmetric double well potentials. Generic potentials are constructed which allow for analytical estimates of the quantum dynamics in the non-relativistic deep tunneling regime, in terms of the tunneling distance, barrier height and mass (or moment of inertia). For cyclic systems, the results may be scaled to agree well with periodic potentials for which semi-analytical results in terms of Mathieu functions exist. Starting from a wavepacket which is initially localized in one of the potential wells, the subsequent periodic tunneling is associated with tunneling velocities. These velocities (or angular velocities) are evaluated as the ratio of the flux densities versus the probability densities. The maximum velocities are found under the top of the barrier where they scale as the square root of the ratio of barrier height and mass (or moment of inertia), independent of the tunneling distance. They are applied exemplarily to several prototypical molecular models of non-cyclic and cyclic tunneling, including ammonia inversion, Cope rearrangement of semibullvalene, torsions of molecular fragments, and rotational tunneling in strong laser fields. Typical maximum velocities and angular velocities are in the order of a few km/s and from 10 to 100 THz for our non-cyclic and cyclic systems, respectively, much faster than time-averaged velocities. Even for the more extreme case of an electron tunneling through a barrier of height of one Hartree, the velocity is only about one percent of the speed of light. Estimates of the corresponding time scales for passing through the narrow domain just below the potential barrier are in the domain from 2 to 40 fs, much shorter than the tunneling times.

Manz, Jörn; Schild, Axel; Schmidt, Burkhard; Yang, Yonggang

2014-10-01

269

Top Quark Mediated Dark Matter  

E-print Network

We study the top quark portal dominated dark matter interactions, and its implications for the gamma ray line searches. In this picture, the dark matter interactions with photons and gluons are loop induced by the axial anomaly of the top quark current. We show there can be a natural suppression of the tree-level annihilation of dark matter, and the photon channel in turn has a substantial rate when the main annihilation proceeds into gluons. We observe a competition between the indirect detection of gamma ray line and the search with monojet plus missing energy events at LHC, and the 7 TeV data already set an upper bound of ~ 10^{-28} cm^3/s on the photonic annihilation cross section. This upper limit is compatible with a thermal WIMP scenario.

Zhang, Yue

2012-01-01

270

Attitude propulsion technology for TOPS  

NASA Technical Reports Server (NTRS)

The thermoelectric outer planet spacecraft (TOPS) attitude propulsion subsystem (APS) effort is discussed. It includes the tradeoff rationale that went into the selection of an anhydrous hydrazine baseline system, followed by a discussion of the 0.22 N thruster and its integration into a portable, self-contained propulsion module that was designed, developed, and man rated to support the TOPS single-axis attitude control tests. The results of a cold-start feasibility demonstration with a modified thruster are presented. A description of three types of 0.44 thrusters that were procured for in-house evaluation is included along with the results of the test program. This is followed by a description of the APS feed system components, their evaluations, and a discussion of an evaluation of elastomeric material for valve seat seals. A list of new technology items which will be of value for application to future systems of this type is included.

Moynihan, P. I.

1972-01-01

271

Observation of the Top Quark  

Microsoft Academic Search

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

S. Abachi

1995-01-01

272

Molecules in Living Systems  

NSDL National Science Digital Library

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.

2012-06-19

273

Discovering Interstellar Molecules  

Microsoft Academic Search

This paper describes how high resolution spectroscopy has been the key for discovering interstellar molecules and for studying the interstellar medium. The development of radioastronomy in the 1950's has led to the detection of many interstellar molecules in the 1960s and 1970s, and the construction of a new field of research, astrochemistry. The discovery of molecular ions has confirmed the

M. Gerin

2006-01-01

274

Enzymatic DNA molecules  

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

275

What is a Molecule?  

NSDL National Science Digital Library

This video/animation shows that a molecule of water is made up of oxygen and hydrogen atoms. When oxygen and hydrogen atoms exist alone, their properties are different from the properties they have when they are chemically combined to form a water molecule

Wpsu

2007-04-09

276

Top quark studies at hadron colliders  

SciTech Connect

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 b quark jets in candidate events. The most recent measurements of top quark properties by the CDF and DO 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.

Sinervo, P.K. [Univ. of Toronto, Ontario (Canada)

1997-01-01

277

Symmetric instability in the Gulf Stream  

NASA Astrophysics Data System (ADS)

Analyses of wintertime surveys of the Gulf Stream (GS) conducted as part of the CLIvar MOde water Dynamic Experiment (CLIMODE) reveal that water with negative potential vorticity (PV) is commonly found within the surface boundary layer (SBL) of the current. The lowest values of PV are found within the North Wall of the GS on the isopycnal layer occupied by Eighteen Degree Water, suggesting that processes within the GS may contribute to the formation of this low-PV water mass. In spite of large heat loss, the generation of negative PV was primarily attributable to cross-front advection of dense water over light by Ekman flow driven by winds with a down-front component. Beneath a critical depth, the SBL was stably stratified yet the PV remained negative due to the strong baroclinicity of the current, suggesting that the flow was symmetrically unstable. A large eddy simulation configured with forcing and flow parameters based on the observations confirms that the observed structure of the SBL is consistent with the dynamics of symmetric instability (SI) forced by wind and surface cooling. The simulation shows that both strong turbulence and vertical gradients in density, momentum, and tracers coexist in the SBL of symmetrically unstable fronts. SI is a shear instability that draws its energy from geostrophic flows. A parameterization for the rate of kinetic energy (KE) extraction by SI applied to the observations suggests that SI could result in a net dissipation of 33 mW m-2 and 1 mW m-2 for surveys with strong and weak fronts, respectively. The surveys also showed signs of baroclinic instability (BCI) in the SBL, namely thermally direct vertical circulations that advect biomass and PV. The vertical circulation was inferred using the omega equation and used to estimate the rate of release of available potential energy (APE) by BCI. The rate of APE release was found to be comparable in magnitude to the net dissipation associated with SI. This result points to an energy pathway where the GS's reservoir of APE is drained by BCI, converted to KE, and then dissipated by SI and its secondary instabilities. Similar dynamics are likely to be found at other strong fronts forced by winds and/or cooling and could play an important role in the energy balance of the ocean circulation.

Thomas, Leif N.; Taylor, John R.; Ferrari, Raffaele; Joyce, Terrence M.

2013-07-01

278

Concrete Representation and Separability Criteria for Symmetric Quantum State  

NASA Astrophysics Data System (ADS)

Using the typical generators of the special unitary groups S U(2), the concrete representation of symmetric quantum state is established, then the relations satisfied by those coefficients in the representation are presented. Based on the representation of density matrix, the PPT criterion and CCNR criterion are proved to be equivalent on judging the separability of symmetric quantum states. Moreover, it is showed that the matrix ? ? of symmetric quantum state only has five efficient entries, thus the calculation of ?? ? ? is simplified. Finally, the quantitative expressions of real symmetric quantum state under the ?? ? ? separability criterion are obtained.

Li, Chang'e.; Tao, Yuanhong; Zhang, Jun; Li, Linsong; Nan, Hua

2014-09-01

279

On the structure of symmetric self-dual Lie algebras  

NASA Astrophysics Data System (ADS)

A finite-dimensional Lie algebra is called (symmetric) self-dual, if it possesses an invariant nondegenerate (symmetric) bilinear form. Symmetric self-dual Lie algebras have been studied by Medina and Revoy, who have proven a very useful theorem about their structure. In this paper we prove a refinement of their theorem that has wide applicability in conformal field theory, where symmetric self-dual Lie algebras start to play an important role due to the fact that they are precisely the Lie algebras that admit a Sugawara construction. We also prove a few corollaries that are important in conformal field theory.

Figueroa-O'Farrill, José M.; Stanciu, Sonia

1996-08-01

280

The Symmetrization Method in Problems on Nonoverlapping Domains  

NASA Astrophysics Data System (ADS)

A new approach to the use of symmetrization is considered. Sterner symmetrization is taken as the main tool. An arbitrary symmetrization transformation connected with a given quadratic differential \\mathcal{Q}(z)\\,dz^2 is obtained by successive application of the mapping \\zeta=\\int \\mathcal{Q}^{1/2}(z)\\,dz and Steiner symmetrization. As a consequence of the main theorem, the corresponding results of Lavrent'ev, Goluzin, Jenkins, and others are refined and generalized to the case of domains of arbitrary connectivity (not necessarily having a filling).Bibliography: 21 titles.

Dubinin, V. N.

1987-02-01

281

Geometric inequalities for axially symmetric black holes  

E-print Network

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.

Sergio Dain

2011-11-15

282

Quantum searches on highly symmetric graphs  

NASA Astrophysics Data System (ADS)

We study scattering quantum walks on highly symmetric graphs and use the walks to solve search problems on these graphs. The particle making the walk resides on the edges of the graph, and at each time step scatters at the vertices. All of the vertices have the same scattering properties except for a subset of special vertices. The object of the search is to find a special vertex. A quantum circuit implementation of these walks is presented in which the set of special vertices is specified by a quantum oracle. We consider the complete graph, a complete bipartite graph, and an M -partite graph. In all cases, the dimension of the Hilbert space in which the time evolution of the walk takes place is small (between three and six), so the walks can be completely analyzed analytically. Such dimensional reduction is due to the fact that these graphs have large automorphism groups. We find the usual quadratic quantum speedups in all cases considered.

Reitzner, Daniel; Hillery, Mark; Feldman, Edgar; Bužek, Vladimír

2009-01-01

283

Nonlinear Maximal Monotone Extensions of Symmetric Operators  

E-print Network

Given a linear semi-bounded symmetric operator $S\\ge -\\omega$, we explicitly define, and provide their nonlinear resolvents, nonlinear maximal monotone operators $A_\\Theta$ of type $\\lambda>\\omega$ (i.e. generators of one-parameter continuous nonlinear semi-groups of contractions of type $\\lambda$) which coincide with the Friedrichs extension of $S$ on a convex set $\\mathscr K$ containing ${\\mathscr D}(S)$. The extension parameter $\\Theta\\subset{\\mathfrak h}\\times{\\mathfrak h}$ ranges over the set of nonlinear maximal monotone relations on an auxiliary Hilbert space $\\mathfrak h$ isomorphic to the deficiency subspace of $S$. Moreover $A_\\Theta+\\lambda$ is a sub-potential operator (i.e. is the sub-differential of a lower semicontinuos convex function) whenever $\\Theta$ is sub-potential. Examples describing Laplacians with nonlinear singular perturbations supported on null sets and Laplacians with nonlinear boundary conditions on a bounded set are given.

Andrea Posilicano

2014-04-09

284

Cracked shells under skew-symmetric loading  

NASA Technical Reports Server (NTRS)

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.

Lelale, F.

1982-01-01

285

Invisibility in PT-symmetric complex crystals  

E-print Network

Bragg scattering in sinusoidal PT-symmetric complex crystals of finite thickness is theoretically investigated by the derivation of exact analytical expressions for reflection and transmission coefficients in terms of modified Bessel functions of first kind. The analytical results indicate that unidirectional invisibility, recently predicted for such crystals by coupled-mode theory [Z. Lin et al., Phys. Rev. Lett. 106, 213901 (2011)], breaks down for crystals containing a large number of unit cells. In particular, for a given modulation depth in a shallow sinusoidal potential, three regimes are encountered as the crystal thickness is increased. At short lengths the crystal is reflectionless and invisible when probed from one side (unidirectional invisibility), whereas at intermediate lengths the crystal remains reflectionless but not invisible; for longer crystals both unidirectional reflectionless and invisibility properties are broken.

Stefano Longhi

2011-11-15

286

Implications of nonlinearity for spherically symmetric accretion  

E-print Network

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.

Sen, Sourav

2012-01-01

287

Symmetric Lipofibromatous Hamartoma Affecting Digital Nerves  

PubMed Central

Lipofibromatous hamartoma of the nerve is a benign tumor, which affects the major nerves and their branches in the human body. It is often found in the median nerve of the hand and is commonly associated with macrodactyly, but it is rarely found in the digital nerves at the peripheral level. This tumor is often found in young adults and may go through a self-limiting course. However, operation is indicated when the tumor size is large or when the associated nerve compressive symptoms are present. We have experienced a rare case of lipofibromatous hamartoma that symmetrically involved the volar digital nerves of both index fingers on the ulnar side. With the aid of a microscope, we dissected and removed the tumor as much as possible without sacrificing the nerve. No sensory change occurred in both fingers and no sign of recurrence was observed upon follow-up. PMID:15744823

Jung, Sung-No; Yim, Youngmin

2005-01-01

288

Axially Symmetric Post-Newtonian Stellar Systems  

E-print Network

We introduce a method to obtain self-consistent, axially symmetric, thin disklike stellar models in the first post-Newtonian (1PN) approximation. The models obtained are fully analytical and corresponds to the post-Newtonian generalizations of classical ones. By introducing in the field equations provided by the 1PN approximation a known distribution function (DF) corresponding to a Newtonian model, two fundamental equations determining the 1PN corrections are obtained, which are solved using the Hunter method. The rotation curves of the 1PN-corrected models differs from the classical ones and, for the generalized Kalnajs discs, the 1PN corrections are clearly appreciable with values of the mass and radius of a typical galaxy. On the other hand, the relativistic mass correction can be ignored for all models.

Camilo Akimushkin; Javier Ramos-Caro; Guillermo A. González

2009-10-08

289

Acoustic horizons in axially symmetric relativistic accretion  

E-print Network

Transonic accretion onto astrophysical objects is a unique example of analogue black hole realized in nature. In the framework of acoustic geometry we study axially symmetric accretion and wind of a rotating astrophysical black hole or of a neutron star assuming isentropic flow of a fluid described by a polytropic equation of state. In particular we analyze the causal structure of multitransonic configurations with two sonic points and a shock. Retarded and advanced null curves clearly demonstrate the presence of the acoustic black hole at regular sonic points and of the white hole at the shock. We calculate the analogue surface gravity and the Hawking temperature for the inner and the outer acoustic horizons.

Hrvoje Abraham; Neven Bilic; Tapas K. Das

2005-09-15

290

New VLBA Identifications of Compact Symmetric Objects  

E-print Network

The class of radio sources known as Compact Symmetric Objects (CSOs) is of particular interest in the study of the evolution of radio galaxies. CSOs are thought to be young (probably ~10^4 years), and a very high fraction of them exhibit HI absorption toward the central parsecs. The HI, which is thought to be part of a circumnuclear torus of accreting gas, can be observed using the VLBA with high enough angular resolution to map the velocity field of the gas. This velocity field provides new information on the accretion process in the central engines of these young sources. We have identified 9 new CSOs from radio continuum observations for the VLBA Calibrator Survey, increasing the number of known CSOs by almost 50%.

A. B. Peck; G. B. Taylor

1999-11-16

291

Exact Spherically Symmetric Solutions in Massive Gravity  

E-print Network

A phase of massive gravity free from pathologies can be obtained by coupling the metric to an additional spin-two field. We study the gravitational field produced by a static spherically symmetric body, by finding the exact solution that generalizes the Schwarzschild metric to the case of massive gravity. Besides the usual 1/r term, the main effects of the new spin-two field are a shift of the total mass of the body and the presence of a new power-like term, with sizes determined by the mass and the shape (the radius) of the source. These modifications, being source dependent, give rise to a dynamical violation of the Strong Equivalence Principle. Depending on the details of the coupling of the new field, the power-like term may dominate at large distances or even in the ultraviolet. The effect persists also when the dynamics of the extra field is decoupled.

Z. Berezhiani; D. Comelli; F. Nesti; L. Pilo

2008-03-12

292

Top condensation as a motivated explanation of the top forward-backward asymmetry  

E-print Network

Models of top condensation can provide both a compelling solution to the hierarchy problem as well as an explanation of why the top-quark mass is large. The spectrum of such models, in particular topcolor-assisted technicolor, includes top-pions, top-rhos and the top-Higgs, all of which can easily have large top-charm or top-up couplings. Large top-up couplings in particular would lead to a top forward-backward asymmetry through $t$-channel exchange, easily consistent with the Tevatron measurements. Intriguingly, there is destructive interference between the top-mesons and the standard model which conspire to make the overall top pair production rate consistent with the standard model. The rate for same-sign top production is also small due to destructive interference between the neutral top-pion and the top-Higgs. Flavor physics is under control because new physics is mostly confined to the top quark. In this way, top condensation can explain the asymmetry and be consistent with all experimental bounds. There are many additional signatures of topcolor with large tu mixing, such as top(s)+jet(s) events, in which a top and a jet reconstruct a resonance mass, which make these models easily testable at the LHC.

Yanou Cui; Zhenyu Han; Matthew D. Schwartz

2011-06-15

293

What’s at the top in the top-down control of action? Script-sharing and ‘top-top’ control of action in cognitive experiments  

Microsoft Academic Search

The distinction between bottom-up and top-down control of action has been central in cognitive psychology, and, subsequently, in functional neuroimaging. While the model has proven successful in describing central mechanisms in cognitive experiments, it has serious shortcomings in explaining how top-down control is established. In particular, questions as to what is at the top in top-down control lead us to

Andreas Roepstorff; Chris Frith

2004-01-01

294

Evidence for production of single top quarks  

Microsoft Academic Search

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

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

295

Heavy flavour physics from top to bottom  

SciTech Connect

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.

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

1997-01-01

296

Heavy flavour physics from top to bottom  

SciTech Connect

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{anti B} mixing results. An outlook of perspectives for top and B physics in Run II starting in 1999 is also given.

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

1998-02-01

297

BRAIN TUMOR SEGMENTATION WITH SYMMETRIC TEXTURE AND SYMMETRIC INTENSITY-BASED DECISION FORESTS  

PubMed Central

Accurate automated segmentation of brain tumors in MR images is challenging due to overlapping tissue intensity distributions and amorphous tumor shape. However, a clinically viable solution providing precise quantification of tumor and edema volume would enable better pre-operative planning, treatment monitoring and drug development. Our contributions are threefold. First, we design efficient gradient and LBPTOP based texture features which improve classification accuracy over standard intensity features. Second, we extend our texture and intensity features to symmetric texture and symmetric intensity which further improve the accuracy for all tissue classes. Third, we demonstrate further accuracy enhancement by extending our long range features from 100mm to a full 200mm. We assess our brain segmentation technique on 20 patients in the BraTS 2012 dataset. Impact from each contribution is measured and the combination of all the features is shown to yield state-of-the-art accuracy and speed.

Bianchi, Anthony; Miller, James V.; Tan, Ek Tsoon; Montillo, Albert

2014-01-01

298

Psychophysical and physiological responses to lifting symmetrical and asymmetrical loads symmetrically and asymmetrically  

Microsoft Academic Search

Eighteen adult males (mean age 22·6 years, weight 78·6kg and height 176·6cm) participated in a study designed to investigate the effects of symmetrical and asymmetrical lifting on the maximum acceptable weight of lift and the resulting physiological cost. Each subject performed sixty different lifting tasks involving two lifting heights, three lifting frequencies and five containers. For each lifting task, the

ANIL MITAL; HAMID F. FARD

1986-01-01

299

Ownership structure and top executive turnover  

Microsoft Academic Search

We report that ownership structure significantly affects the likelihood of a change in top executive. Controlling for stock price performance, the probability of top executive turnover is negatively related to the ownership stake of officers and directors and positively related to the presence of an outside blockholder. In addition, the likehood of a change in top executive is significantly less

David J. Denis; Diane K. Denis; Atulya Sarin

1997-01-01

300

The Top Quark Pushpalatha C. Bhat  

E-print Network

0 bosons. Fig. 1 shows the building blocks of the Standard Model. The top quark was the important of the Standard Model. 1 #12; The discovery of the top quark is a major triumph of the Standard Model and possibly the world in late 1970's, shortly after the discovery of the b­quark, it turns out that the top quarks could

Bhat, Pushpalatha

301

Top Mass Measurements at the Tevatron  

E-print Network

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.

M. H. L. S. Wang

2009-04-02

302

Top Quark Physics at the DZero Experiment  

Microsoft Academic Search

In this paper I present the latest results on top quark physics from the DZero collaboration since the discovery of the top quark in March 1995. I summarize the discovery results, discuss progress since the discovery, and show how we can measure the top quark mass using three separate techniques. The measurements were made at the Fermilab Tevatron, a ppbar

A. P. Heinson

1996-01-01

303

Discovery of single top quark production  

Microsoft Academic Search

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,

Dag Gillberg; for the D

2009-01-01

304

Top quark as a resonance  

E-print Network

We suggest the description of the dressed fermion propagator with parity non-conservation in the form with separated positive and negative energy poles. We found general form of the $\\gamma$-matrix off-shell projectors and corresponding resonance factors. The parity violation leads to deviation of resonance factors from the naive Breit--Wigner form and to appearance of non-trivial spin corrections. However, for top quark with SM vertex the resonance factor returns to the standard one due to $\\Gamma/m\\ll1$.

A. E. Kaloshin; V. P. Lomov

2011-11-05

305

Testing for Life's Molecules  

NSDL National Science Digital Library

In this activity, learners conduct tests for proteins, glucose, and starch. At the beginning of the activity, learners choose three items to test: one known to be ânever alive," one known to be âonce was alive,â and one mystery item. In addition, each station includes a positive control. By the end of the experiment, learners should be familiar with some of the major organic molecules and should recognize that living things, and substances derived from them, are made of organic molecules. Use this activity to bring in topics surrounding nutrition, health, and digestion--since our bodies are made up of organic molecules, we need each of these molecules as nutrients in our food.

Salter, Irene

2012-09-28

306

Of Molecules and Models.  

ERIC Educational Resources Information Center

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)

Brinner, Bonnie

1992-01-01

307

Discrete energy transport in collagen molecules  

NASA Astrophysics Data System (ADS)

The modulational instability in the three coupled ?-polypeptide chains of a collagen molecule is investigated. Choosing symmetric and asymmetric solutions, and applying the so-called rotating-wave approximation, we describe the dynamics of the system by the discrete nonlinear Schrödinger (DNLS) equation. The linear stability analysis of the continuous wave solution is performed. The numerical simulations show the generation of trains of solitonic structures in the lattice with increasing amplitude as time progresses. The effect of damping and noise forces of the physiological temperature (T = 300 K) introduces an erratic behavior to the formed patterns, reinforcing the idea that the energy used in metabolic processes is confined to specific regions for efficiency.

Alain, Mvogo; Germain, H. Ben-Bolie; Timoléon, C. Kofané

2014-09-01

308

The Isotopic Anatomies of Molecules and Minerals  

NASA Astrophysics Data System (ADS)

Most natural compounds are composed of diverse isotopologues that differ in the number and/or symmetrically unique atomic locations of isotopic substitutions. Little of this isotopic diversity is observed by conventional methods of stable isotope geochemistry, which generally measure concentrations of rare isotopes without constraining differences in isotopic composition between different atomic sites or nonrandom probabilities of multiple isotopic substitutions in the same molecule. Recent advances in analytical instrumentation and methodology have created a set of geochemical tools—geothermometers, biosynthetic signatures, forensic fingerprints—based on these position-specific isotope effects and multiply substituted isotopologues. This progress suggests we are entering a period in which many new geochemical tools of this type will be created. This review describes the principles, background, analytical methods, existing applied tools, and likely future progress of this emerging field.

Eiler, John M.

2013-05-01

309

Constraints on the uncertainties of entangled symmetric qubits  

E-print Network

We derive necessary and sufficient inseparability conditions imposed on the variance matrix of symmetric qubits. These constraints are identified by examining a structural parallelism between continuous variable states and two qubit states. Pairwise entangled symmetric multiqubit states are shown here to obey these constraints. We also bring out an elegant local invariant structure exhibited by our constraints.

A. R. Usha Devi; M. S. Uma; R. Prabhu; A. K. Rajagopal

2006-01-05

310

Progressive symmetric erythrokeratoderma with nephrotic syndrome: Coincidence or new association?  

PubMed Central

Progressive symmetric erythrokeratoderma (PSEK) is a rare genodermatosis with variable inheritance. It is characterized by symmetrical, erythematous, and hyperkeratotic plaques on the extremities. We report a case of a 15-year-old boy with PSEK of autosomal recessive inheritance associated with nephrotic syndrome. PMID:24350023

Sacchidanand, S; Sahana, M. S.; Kamoji, Sushruth G.; Asha, G. S.

2013-01-01

311

Second-order symmetric duality with cone constraints  

NASA Astrophysics Data System (ADS)

Wolfe and Mond-Weir type second-order symmetric duals are formulated and appropriate duality theorems are established under [eta]-bonvexity/[eta]-pseudobonvexity assumptions. This formulation removes several omissions in an earlier second-order primal dual pair introduced by Devi [Symmetric duality for nonlinear programming problems involving [eta]-bonvex functions, European J. Oper. Res. 104 (1998) 615-621].

Gulati, T. R.; Gupta, S. K.; Ahmad, I.

2008-10-01

312

A Bootstrap Model Selection Criterion Based on Kullback's Symmetric Divergence  

E-print Network

A Bootstrap Model Selection Criterion Based on Kullback's Symmetric Divergence Katholieke corrected variant of KIC develop for the purpose of sources separation. Our variant utilizes bootstrapping is assumed by the authors. 1 #12; A BOOTSTRAP MODEL SELECTION CRITERION BASED ON KULLBACK'S SYMMETRIC

313

Reducing symmetric polarization aberrations in a lens by annealing  

Microsoft Academic Search

Radially symmetric retardance was found in antireflection coated, molded aspheric glass lenses by measurement with a Mueller matrix imaging polarimeter. The source of the unexpected polarization aberration is traced to a remarkably symmetric radial stress birefringence in the glass believed to arise during fire-polishing of the surfaces. While annealing the lenses relieves much of the stress birefringence, reducing the retardance

J. Wolfe; R. A. Chipman

2004-01-01

314

Twistor spinors on Lorentzian symmetric spaces August 25, 1999  

E-print Network

(see [Pen67], [PR86], [NW84]). They are related to Killing vector fields in semiTwistor spinors on Lorentzian symmetric spaces Helga Baum August 25, 1999 Abstract An indecomposable Riemannian symmetric space which admits nontrivial twistor spinors has constant sectional

Baum, Helga

315

New spin on Einstein's non-symmetric metric tensor  

E-print Network

A solution to the gravitational field equations based on a non-symmetric metric tensor is examined. Unlike Einstein's interpretation of electromagnetism, or Moffat's generalized gravity, it is shown that the non-symmetric part of the metric tensor is the potential of the spin field. This is in agreement with string theory and provides a natural coupling between gravitation and strings.

Richard T. Hammond

2012-07-21

316

Spherically Symmetric Solution in Bi-metric theory of Gravity  

E-print Network

The possibility of spherically symmetric solutions in bi-metric theory of gravity is examined. It is shown that two possible black hole type solutions exists in the model. Spherically symmetric solution of general theory of relativity is recovered in the absence of the second metric. The result is compared with other bi-metric models as well as general theory of relativity.

Anoop Narayanan P E; P K Suresh

2014-03-27

317

Symmetric designs on Lie algebras and interactions of hamiltonian systems  

Microsoft Academic Search

Nonhamiltonian interaction of hamiltonian systems is considered. Dynamical equations are constructed by use of symmetric designs on Lie algebras. The results of analysis of these equations show that some class of symmetric designs on Lie algebras beyond Jordan ones may be useful for a description of almost periodic, asymptotically periodic, almost asymptotically periodic, and, possibly, more chaotic systems. However, the

Denis V. Juriev; Erwin Schrodinger

1995-01-01

318

CASCADIC MULTILEVEL ALGORITHMS FOR SYMMETRIC SADDLE POINT SYSTEMS  

E-print Network

CASCADIC MULTILEVEL ALGORITHMS FOR SYMMETRIC SADDLE POINT SYSTEMS CONSTANTIN BACUTA Abstract. In this paper, we introduce a multilevel algorithm for ap- proximating variational formulations of symmetric an efficient solver such as the gradient or the conjugate gradient algorithm for inverting a Schur complement

Bacuta, Constantin

319

Spherically Symmetric Space-Time with Two Cosmological Constants  

Microsoft Academic Search

We present the analytic spherically symmetric solution of the Einstein equations, which has de Sitter asymptotics for both r ? 8 and r ? 0. This two-lambda spherically symmetric solution is globally regular. At the range of mass parameter Mcr1 cr2 it has three horizons and describes a neutral black hole whose singularity is replaced by a cosmological constant ?

I. Dymnikova; B. Soltysek

1998-01-01

320

Reciprocal Symmetric Boltzmann Function and Unified Boson-Fermion Statistics  

E-print Network

The differential equation for Boltzmann's function is replaced by the corresponding discrete finite difference equation. The difference equation is, then, symmetrized so that the equation remains invariant when step d is replaced by -d. The solutions of this equation come in Boson-Fermion pairs. Reciprocal symmetric Boltzmann's function, thus, unifies both Bosonic and Fermionic distributions.

Mushfiq Ahmad; Muhammad O. G. Talukder

2007-05-05

321

A symmetric surface micromachined gyroscope with decoupled oscillation modes  

E-print Network

A symmetric surface micromachined gyroscope with decoupled oscillation modes Said Emre Alper Abstract This paper reports a new symmetric gyroscope structure that allows both matched resonant beam design. The gyroscope structure is designed using a standard three-layer polysilicon surface

Akin, Tayfun

322

Sign elements in symmetric groups Jrn B. Olsson  

E-print Network

Sign elements in symmetric groups Jørn B. Olsson Dept. of Mathematical Sciences University of Copenhagen, Denmark Nagoya, September 4, 2008 Jørn B. Olsson Sign elements in symmetric groups #12 definition of sign elements and sign classes in finite groups. Content of talk: · Generalities about group

Takahashi, Ryo

323

MHD Integrated Topping Cycle Project  

SciTech Connect

The overall objective of the project is to design and construct prototypical hardware for an integrated MHD topping cycle, and conduct long duration proof-of-concept tests of integrated system at the US DOE Component Development and Integration Facility in Butte, Montana. The results of the long duration tests will augment the existing engineering design data base on MHD power train reliability, availability, maintainability, and performance, and will serve as a basis for scaling up the topping cycle design to the next level of development, an early commercial scale power plant retrofit. The components of the MHD power train to be designed, fabricated, and tested include: A slagging coal combustor with a rated capacity of 50 MW thermal input, capable of operation with an Eastern (Illinois {number sign}6) or Western (Montana Rosebud) coal, a segmented supersonic nozzle, a supersonic MHD channel capable of generating at least 1.5 MW of electrical power, a segmented supersonic diffuser section to interface the channel with existing facility quench and exhaust systems, a complete set of current control circuits for local diagonal current control along the channel, and a set of current consolidation circuits to interface the channel with the existing facility inverter.

Not Available

1992-01-01

324

Top Quark Studies at D0  

E-print Network

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.

R. Y. Peters

2014-08-10

325

Solution of the embedding problem and decomposition of symmetric matrices.  

PubMed Central

A solution of the problem of calculating cartesian coordinates from a matrix of interpoint distances (the embedding problem) is reported. An efficient and numerically stable algorithm for the transformation of distances to coordinates is then obtained. It is shown that the embedding problem is intimately related to the theory of symmetric matrices, since every symmetric matrix is related to a general distance matrix by a one-to-one transformation. Embedding of a distance matrix yields a decomposition of the associated symmetric matrix in the form of a sum over outer products of a linear independent system of coordinate vectors. It is shown that such a decomposition exists for every symmetric matrix and that it is numerically stable. From this decomposition, the rank and the numbers of positive, negative, and zero eigenvalues of the symmetric matrix are obtained directly. PMID:3857574

Sippl, M J; Scheraga, H A

1985-01-01

326

The Top American Research Universities 2001  

NSDL National Science Digital Library

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.

2001-01-01

327

Symmetrization in the geometric theory of functions of a complex variable  

NASA Astrophysics Data System (ADS)

CONTENTSIntroduction Chapter I. Symmetrization transformations §1. Capacities 1. Functions satisfying the Lipschitz condition 2. Condenser capacity 3. Reduced modulus and inner radius §2. Polarization §3. Symmetrization 1. Schwarz symmetrization 2. Steiner symmetrization 3. Circular symmetrization 4. Symmetrization of functions 5. Elliptic symmetrization 6. Symmetrization with respect to a circle §4. Piecewise separating symmetrization 1. Separating transformation 2. Other types of piecewise separating symmetrization §5. Averaging transformations §6. Dissymmetrization Comments on Chapter I Chapter II. Application of symmetrization transformations to some problems in geometric function theory §7. Inequalities for moduli and capacities 1. Annuli 2. The Fekete problem3. Subsets of the unit circle4. Gonchar's problem5. Polygons §8. Estimates of harmonic measure §9. Problems of extremal partitioning1. Fixed poles2. Free poles §10. Univalent functions 1. The Szegö problem 2. The Bazilevich problem 3. Distortion theorems 4. Covering theorems §11. Multivalent functions 1. Symmetrization of plane images 2. Symmetrization of a Riemann surface Unsolved problems References

Dubinin, V. N.

1994-02-01

328

Synthesis of functionalized triphenylenes and dibenzopyrenes Precursor molecules for polymeric discotic liquid crystals  

Microsoft Academic Search

Discotic liquid crystals represent a promising class of new materials, for example, with respect to their photoconductivity properties. To tailor the processability and mesophase behaviour of such materials, specifically functionalized cores are required as precursor molecules for discotic oligomers, polymers and networks. The paper presents a simple synthetic strategy leading to unsymmetrically functionalized triphenylene and dibenzopyrene derivatives. Furthermore new symmetrical

P. Henderson; H. Ringsdorf; P. Schuhmacher

1995-01-01

329

Unimolecular Reaction Dynamics of Large Polyatomic Molecules.  

NASA Astrophysics Data System (ADS)

Scope and method of study. Classical and semiclassical dynamics were used in an attempt to at least partially answer the following questions: (i) Can we predict the presence or absence of statistical behavior in polyatomic molecules and, in either case, explain why? (ii) To what degree can we model the detailed, full-dimensional unimolecular reaction dynamics of large molecules? (iii) Are the vibrational dynamics of highly excited polyatomic molecules chaotic? (iv) Can the "zero-point energy problem" in classical trajectory calculations be "corrected"? (v) Can we induce mode specificity in symmetric, double-well tunneling splittings?. Findings and conclusions. (i) Classical trajectory calculations performed on 2-chloroethyl radical indicate that the system is not mode specific. Moreover, comparison of the trajectory results to those obtained using Monte Carlo transition-state theory reveals that 2-chloroethyl behaves statistically. We suggest that three conditions likely to favor nonstatistical behavior are (a) low levels of excitation (relative to the reaction threshold); (b) a reaction coordinate that does not lead to large changes in the chemical bonding; (c) the existence of an activation coordinate that is strongly coupled to the reaction coordinate but only weakly coupled to the "bath". (ii) The unimolecular reaction dynamics of the RDX molecule were studied. First -order rate coefficients, branching ratios, and product -state distributions were computed from microcanonical ensembles of trajectories. The results are in qualitative accord with experimental data. We conclude that classical trajectories can be used to treat the reaction dynamics in large systems. (iii) Power spectra were used to study the vibrational dynamics of vibrationally excited SiF_4, C_2H_4, CH _3ONO, 2-chloroethyl radical, and RDX. The results indicate that the intramolecular dynamics of large, highly excited polyatomic molecules are largely nonchaotic, leaving open the possibility of mode-specific effects in large-molecule reaction dynamics. (iv) Two methods for constraining zero-point energies in classical trajectories were examined. Neither of the constraints is suitable for use in realistic systems. We are led to question whether it is possible to actively treat the zero -point energy problem without introducing problems of a far more serious nature than those we are trying to remedy. (v) A simple semiclassical method was used to compute the tunneling splitting in a prototypical malonaldehyde molecule as a function of various excitation schemes. The results indicate a sensitive dependence of the splitting on the kind of initial conditions used.

Sewell, Thomas Dan

330

PT-symmetric laser-absorber  

E-print Network

In a recent work, Y.D. Chong et al. [Phys. Rev. Lett. {\\bf 105}, 053901 (2010)] proposed the idea of a coherent perfect absorber (CPA) as the time-reversed counterpart of a laser, in which a purely incoming radiation pattern is completely absorbed by a lossy medium. The optical medium that realizes CPA is obtained by reversing the gain with absorption, and thus it generally differs from the lasing medium. Here it is shown that a laser with an optical medium that satisfies the parity-time $(\\mathcal{PT})$ symmetry condition $\\epsilon(-\\mathbf{r})=\\epsilon^*(\\mathbf{r})$ for the dielectric constant behaves simultaneously as a laser oscillator (i.e. it can emit outgoing coherent waves) and as a CPA (i.e. it can fully absorb incoming coherent waves with appropriate amplitudes and phases). Such a device can be thus referred to as a $\\mathcal{PT}$-symmetric CPA-laser. The general amplification/absorption features of the $\\mathcal{PT}$ CPA-laser below lasing threshold driven by two fields are determined.

Stefano Longhi

2010-08-31

331

Phase Behavior of Symmetric Sulfonated Block Copolymers  

SciTech Connect

Phase behavior of poly(styrenesulfonate-methylbutylene) (PSS-PMB) block copolymers was studied by varying molecular weight, sulfonation level, and temperature. Molecular weights of the copolymers range from 2.9 to 117 kg/mol. Ordered lamellar, gyroid, hexagonally perforated lamellae, and hexagonally packed cylinder phases were observed in spite of the fact that the copolymers are nearly symmetric with PSS volume fractions between 0.45 and 0.50. The wide variety of morphologies seen in our copolymers is inconsistent with current theories on block copolymer phase behavior such as self-consistent field theory. Low molecular weight PSS-PMB copolymers (<6.2 kg/mol) show order-order and order-disorder phase transitions as a function of temperature. In contrast, the phase behavior of high molecular weight PSS-PMB copolymers (>7.7 kg/mol) is independent of temperature. Due to the large value of Flory-Huggins interaction parameter, x, between the sulfonated and non-sulfonated blocks, PSS-PMB copolymers with PSS and PMB molecular weights of 1.8 and 1.4 kg/mol, respectively, show the presence of an ordered gyroid phase with a 2.5 nm diameter PSS network. A variety of methods are used to estimate x between PSS and PMB chains as a function of sulfonation level. Some aspects of the observed phase behavior of PSS-PMB copolymers can be rationalized using x.

Park, Moon Jeong; Balsara, Nitash P. (UCB)

2008-08-21

332

Surface gravity in dynamical spherically symmetric spacetimes  

E-print Network

A definition of surface gravity at the apparent horizon of dynamical spherically symmetric spacetimes is proposed. It is based on a unique foliation by ingoing null hypersurfaces. The function parametrizing the hypersurfaces can be interpreted as the phase of a light wave uniformly emitted by some far-away static observer. The definition gives back the accepted value of surface gravity in the static case by virtue of its nonlocal character. Although the definition is motivated by the behavior of outgoing null rays, it turns out that there is a simple connection between the generalized surface gravity, the acceleration of any radially moving observer, and the observed frequency change of the infalling light signal. In particular, this gives a practical and simple method of how any geodesic observer can determine surface gravity by measuring only the redshift of the infalling light wave. The surface gravity can be expressed as an integral of matter field quantities along an ingoing null line, which shows that it is a continuous function along the apparent horizon. A formula for the area change of the apparent horizon is presented, and the possibility of thermodynamical interpretation is discussed. Finally, concrete expressions of surface gravity are given for a number of four-dimensional and two-dimensional dynamical black hole solutions.

G. Fodor; K. Nakamura; Y. Oshiro; A. Tomimatsu

1996-03-22

333

Skyrmions and vector mesons: a symmetric approach  

SciTech Connect

We propose an extension of the effective, low-energy chiral Lagrangian known as the Skyrme model, to one formulated by a non-linear sigma model generalized to include vector mesons in a symmetric way. The model is based on chiral SU(6) x SU(6) symmetry spontaneously broken to static SU(6). The rho and other vector mesons are dormant Goldstone bosons since they are in the same SU(6) multiplet as the pion and other pseudoscalars. Hence the manifold of our generalized non-linear sigma model is the coset space (SU(6) x SU(6))/Su(6). Relativistic effects, via a spin-dependent mass term, break the static SU(6) and give the vectors a mass. The model can then be fully relativistic and covariant. The lowest-lying Skyrmion in this model is the whole baryonic 56-plet, which splits into the octet and decuplet in the presence of relativistic SU(6)-breaking. Due to the built-in SU(6) and the presence of vector mesons, the model is expected to have better phenomenological results, as well as providing a conceptually more unified picture of mesons and baryons. 29 references.

Caldi, D.G.

1984-01-01

334

Enhancement and suppression effect of molecules on nanocavity plasmon emissions excited by tunneling electrons  

NASA Astrophysics Data System (ADS)

We use tunneling electron induced luminescence techniques to investigate the role of adsorbed molecules in nanocavity plasmon (NCP) mediated emissions. Porphyrin molecules directly adsorbed on metals are found to suppress NCP emissions, while molecules on top of an inserted ultrathin oxide layer on the metal substrate yield enhanced NCP emissions. We attribute such difference in enhancement versus suppression to a competing mechanism of two major roles of molecules on the local field enhancement: geometrical spacer and dynamic dipole oscillator. The latter could become dominant when molecules are sufficiently decoupled from the substrate, leading to the overall enhancement of NCP emissions.

Zhang, Y.; Geng, F.; Gao, H. Y.; Liao, Y.; Dong, Z. C.; Hou, J. G.

2010-12-01

335

MHD Integrated Topping Cycle Project  

SciTech Connect

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.

Not Available

1992-07-01

336

TopTenLinks.com  

NSDL National Science Digital Library

If you're interested in finding quality science related Web sites, give Toptenlinks.com a try. The science section contains several sponsored sites as well as specific categories such as chemistry, earth science, environment, news, physics, resources, space, biology, education, and geography resources. Once a category is chosen, the links are then listed and can be reorganized by editors' picks, date added, popularity, votes, and site name. If you're so inclined, you can choose to vote on the quality of specific sites or choose to receive email newsletters that notify subscribers no more than once a week of new top 10 categories they have created. Although brief descriptions of sites would be helpful, the site is a good reference for those seeking quality internet resources.

2002-01-01

337

Spectroscopic Studies on Small Molecules: Chlorine Containing Compounds in the Gas Phase and Electrolytes in Formamide.  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. The work presented in this thesis is concerned with the spectroscopic studies on the small molecules: chlorine containing compounds in the gaseous phase and electrolytes in formamide. Firstly, the work is concerned with the observation and analysis of the ro-vibrational spectra of some symmetric top molecules in the gas phase. The millimetre wave spectra of CH_3 ^{37}Cl in its gamma _3 state, have been measured and analysed to give the rotational constants and the centrifugal distortion constants together with values of the quadrupole coupling constants. The values agree well with the less precise values from high resolution infrared spectra for the ground state of CH_3^{37 }Cl. The quadrupole effects for each state have been evaluated to third order treatment. The microwave and millimetre wave spectra of methyl chloroform, CH_3C^ {35}Cl_3, have been measured and analysed their quadrupole structures in the ground state, the torsional state v_6 = 1 and the lowest doubly degenerate state v _{12} = 1. In the ground and the excited degenerate states, the bond axis quadrupole coupling constants were yielded. Higher order centrifugal distortion constants were obtained in its ground state. The Coriolis coupling constant and the centrifugal distortion constants have been used to provide information on the harmonic force field. Good values of the rotational constant were obtained in the ground state and the lowest doubly degenerate state, and also obtained in the torsional state. In addition the microwave spectra of CHCl _3 and CFCl_{3'} which have no off axis hydrogen atom at the non -chlorine end, were analysed to give the quadrupole coupling constants and the geometrical structure. Secondly, the work is concerned with solutions of electrolytes in non-aqueous solvents and their properties using NMR and Raman Spectroscopy. The influence of lithium chloride dissolved in formamide on the formamide molecule have been investigated using ^1H, ^{13 }C, ^{15}N and ^7Li nuclear magnetic resonance spectroscopy. The spin-lattice and spin-spin relaxation times of ^7Li(spin = 3/2) have also been measured. The solvation number of ^7 Li was obtained from the variations of the chemical shifts due to concentration. Raman spectra of tetrafluoroborate and thiocyanate formamide solutions have given a good evidence for the anion solvation.

Seo, Pil Ja.

338

Top polarisation measurement and anomalous $Wtb$ coupling  

E-print Network

Kinematical distributions of the decay products of the top quark carry information on the polarisation of the top as well as on any possible new physics in the decay of the top quark. We construct observables in the form of asymmetries in the kinematical distributions to probe their effects. Charged-lepton angular distributions in the decay are insensitive to anomalous couplings and are a sensitive measure of top polarisation. However, these are difficult to measure in the case of highly boosted top quarks as compared to energy distributions of decay products. These are then sensitive, in general, to both top polarisation and top anomalous couplings. We compare various asymmetries for their sensitivities to the polarisation of the top quark as well as to possible new physics in the $Wtb$ vertex, paying special attention to the case of highly boosted top quarks. We perform a $\\chi ^2$- analysis to determine the regions in the polarisation of the top quark and the couplings of the $Wtb$ vertex constrained by different combinations of the asymmetries.

Arun Prasath; Rohini M. Godbole; Saurabh D. Rindani

2014-05-06

339

MOLECULES IN {eta} CARINAE  

SciTech Connect

We report the detection toward {eta} Carinae of six new molecules, CO, CN, HCO{sup +}, HCN, HNC, and N{sub 2}H{sup +}, and of two of their less abundant isotopic counterparts, {sup 13}CO and H{sup 13}CN. The line profiles are moderately broad ({approx}100 km s{sup -1}), indicating that the emission originates in the dense, possibly clumpy, central arcsecond of the Homunculus Nebula. Contrary to previous claims, CO and HCO{sup +} do not appear to be underabundant in {eta} Carinae. On the other hand, molecules containing nitrogen or the {sup 13}C isotope of carbon are overabundant by about one order of magnitude. This demonstrates that, together with the dust responsible for the dimming of {eta} Carinae following the Great Eruption, the molecules detected here must have formed in situ out of CNO-processed stellar material.

Loinard, Laurent; Menten, Karl M.; Guesten, Rolf [Max-Planck Institut fuer Radioastronomie, Auf dem Huegel 69, 53121 Bonn (Germany); Zapata, Luis A.; Rodriguez, Luis F. [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 3-72, 58090 Morelia, Michoacan (Mexico)

2012-04-10

340

An Antibody Molecule  

NSDL National Science Digital Library

An antibody molecule. (A) Schematic drawing of a typical antibody molecule. As indicated, this protein is Y-shaped and has two identical binding sites for its antigen, one on either arm of the 3Y.2 The protein is composed of four polypeptide chains (two identical heavy chains and two identical and smaller light chains) held together by disulfide bonds. Each chain is made up of several different domains, here shaded either blue or gray. The antigen-binding site is formed where a heavy chain variable domain (VH) and a light chain variable domain (VL) come close together. These are the domains that differ most in their sequence and structure in different antibodies. (B) Ribbon drawing of a light chain showing the parts of the VL domain most closely involved in binding to the antigen in red; these contribute half of the fingerlike loops that fold around each of the antigen molecules in (A).

BEGIN:VCARD VERSION:2.1 FN:Martin Raff N:Raff;Martin REV:2005-04-15 END:VCARD; BEGIN:VCARD VERSION:2.1 FN:Julian Lewis N:Lewis;Julian REV:2005-04-15 END:VCARD; BEGIN:VCARD VERSION:2.1 FN:Alexander Johnson N:Johnson;Alexander REV:2005-04-15 END:VCARD; BEGIN:VCARD VERSION:2.1 FN:Dennis Bray N:Bray;Dennis REV:2005-04-15 END:VCARD; BEGIN:VCARD VERSION:2.1 FN:Bruce Alberts N:Alberts;Bruce REV:2005-04-15 END:VCARD; BEGIN:VCARD VERSION:2.1 FN:Keith Roberts N:Roberts;Keith REV:2005-04-15 END:VCARD

1998-07-01

341

Photochemistry of interstellar molecules  

NASA Technical Reports Server (NTRS)

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.

Stief, L. J.

1971-01-01

342

Discovery of single top quark production  

NASA Astrophysics Data System (ADS)

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--1 of data recorded by the DO detector at the Fermilab Tevatron Collider at centre-of-mass energy 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 s(pp?tb+X,tqb+X) =3.74+0.95-0. 74pb. . Using the same analysis, a measurement of the amplitude of the CKM matrix element Vtb, governing how top and b quarks mix, is also performed. The measurement yields: |VtbfL1| =1.05+0.13-0.12 , where fL1 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.

Gillberg, Dag

343

Wiring up Single Molecules  

NSDL National Science Digital Library

In recent years, circuit design has advanced to achieve extremely small feature sizes -- literally tens of millions of transistors can be integrated in a single chip. This progress has given rise to molecular electronics, the notion of creating electronic devices with single molecules as circuit elements. In this paper, the authors "discuss transistors, where electrons flow through discrete quantum states of a single molecule." Fabrication considerations are outlined, and the current-voltage responses of several such transistors that were fabricated by the authors are shown. The paper concludes by looking ahead to future possibilities of chemically-tailored transistors that could be designed with specific properties.

344

Molecules in Motion  

NSDL National Science Digital Library

In this learning assessment, students demonstrate understanding of the following concepts: solids, liquids and gases, changes of state, convection, and density. Students create a skit where the actors and actresses are molecules, and dramatize, through body motions, how the behavior of molecules results in the observable changes we see. A detailed scoring rubric is included with the resource. The investigation supports material presented in chapter 3 "What Heats the Earth's Interior?" in the textbook, Energy flow, part of Global System Science, an interdisciplinary course for high school students that emphasizes how scientists from a wide variety of fields work together to understand significant problems of global impact.

345

Alphabetical Listing of Molecules  

NSDL National Science Digital Library

This useful, straightforward site will help students understand the structure of molecules through visualization. It was created by W. F. Coleman, Professor of Chemistry at Wellesley College. Here, you will find several common substances including caffeine, penicillin, Viagra, and vitamin A, as well as a few more exotic ones. Using the Chime software, a free chemical structure visualization plug-in for Windows and Macintosh, each molecule isn't simply a static image. It can be rotated for a complete examination, reformatted, and saved in a variety of file formats. A download link for Chime is provided.

2007-06-03

346

Alphabetical Listing of Molecules  

NSDL National Science Digital Library

This useful, straightforward site will help students understand the structure of molecules through visualization. It was created by W. F. Coleman, Professor of Chemistry at Wellesley College. Here, you will find several common substances including caffeine, penicillin, Viagra, and vitamin A, as well as a few more exotic ones. Using the Chime software, a free chemical structure visualization plug-in for Windows and Macintosh, each molecule isn't simply a static image. It can be rotated for a complete examination, reformatted, and saved in a variety of file formats. A download link for Chime is provided.

1998-01-01

347

Mighty Molecule Models  

NSDL National Science Digital Library

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.

Rushton, Greg; Bencomo, Marie; Brown, Tom

2008-01-01

348

Symmetric diffeomorphic registration of fibre orientation distributions.  

PubMed

Registration of diffusion-weighted images is an important step in comparing white matter fibre bundles across subjects, or in the same subject at different time points. Using diffusion-weighted imaging, Spherical Deconvolution enables multiple fibre populations within a voxel to be resolved by computing the fibre orientation distribution (FOD). In this paper, we present a novel method that employs FODs for the registration of diffusion-weighted images. Registration was performed by optimising a symmetric diffeomorphic non-linear transformation model, using image metrics based on the mean squared difference, and cross-correlation of the FOD spherical harmonic coefficients. The proposed method was validated by recovering known displacement fields using FODs represented with maximum harmonic degrees (l(max)) of 2, 4 and 6. Results demonstrate a benefit in using FODs at l(max)=4 compared to l(max)=2. However, a decrease in registration accuracy was observed when l(max)=6 was used; this was likely caused by noise in higher harmonic degrees. We compared our proposed method to fractional anisotropy driven registration using an identical code base and parameters. FOD registration was observed to perform significantly better than FA in all experiments. The cross-correlation metric performed significantly better than the mean squared difference. Finally, we demonstrated the utility of this method by computing an unbiased group average FOD template that was used for probabilistic fibre tractography. This work suggests that using crossing fibre information aids in the alignment of white matter and could therefore benefit several methods for investigating population differences in white matter, including voxel based analysis, tensor based morphometry, atlas based segmentation and labelling, and group average fibre tractography. PMID:21316463

Raffelt, David; Tournier, J-Donald; Fripp, Jurgen; Crozier, Stuart; Connelly, Alan; Salvado, Olivier

2011-06-01

349

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

PubMed Central

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

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

350

Role of skew-symmetric differential forms in mathematics  

E-print Network

Skew-symmetric forms possess unique capabilities. The properties of closed exterior and dual forms, namely, invariance, covariance, conjugacy and duality, either explicitly or implicitly appear in all invariant mathematical formalisms. This enables one to see an internal connection between various branches of mathematics. However, the theory of closed exterior forms cannot be completed without an answer to a question of how the closed exterior forms emerge. In the present paper we discus essentially new skew-symmetric forms, which generate closed exterior forms. Such skew-symmetric forms, which are evolutionary ones, are derived from differential equations, and, in contrast to exterior forms, they are defined on nonintegrable manifolds.

L. I. Petrova

2010-04-05

351

Highly-dispersive electromagnetic induced transparency in planar symmetric metamaterials.  

PubMed

We propose, design and experimentally demonstrate highly-dispersive electromagnetically induced transparency (EIT) in planar symmetric metamaterials actively switched and controlled by angles of incidence. Full-wave simulation and measurement results show EIT phenomena, trapped-mode excitations and the associated local field enhancement of two symmetric metamaterials consisting of symmetrically split rings (SSR) and a fishscale (FS) metamaterial pattern, respectively, strongly depend on angles of incidence. The FS metamaterial shows much broader spectral splitting than the SSR metamaterial due to the surface current distribution variation. PMID:23038311

Lu, Xiqun; Shi, Jinhui; Liu, Ran; Guan, Chunying

2012-07-30

352

Chirally symmetric but confined hadrons at finite density  

E-print Network

At a critical finite chemical potential and low temperature QCD undergoes the chiral restoration phase transition. The folklore tradition is that simultaneously hadrons are deconfined and there appears the quark matter. We demonstrate that it is possible to have confined but chirally symmetric hadrons at a finite chemical potential and hence beyond the chiral restoration point at a finite chemical potential and low temperature there could exist a chirally symmetric matter consisting of chirally symmetric but confined hadrons. If it does happen in QCD, then the QCD phase diagram should be reconsidered with obvious implications for heavy ion programs and astrophysics.

L. Ya. Glozman; R. F. Wagenbrunn

2008-02-03

353

Scattering of solitons by complex symmetric gaussian potentials.  

PubMed

Scattering of bright soliton by -symmetric potential well and barrier is investigated numerically. The numerical results show that increasing strength of real part of -symmetric potential can cause repeated reflection, transmission, and trapping regions due to energy exchange between the kinetic energy of incoming soliton and the internal modes of the potential structure. In addition, the width of the scattering windows increases with increase of the imaginary part of the -symmetric potential. The results obtained can be exploited in the development of interferometry as well as for diodes devices in information technology. PMID:25321582

Al-Marzoug, S M

2014-09-01

354

SYMMETRIC LIVIDITY OF THE SOLES AS SEEN IN PRIVATE PRACTICE  

PubMed Central

As seen in private practice, symmetric lividity of the soles is a relatively common condition which occurs predominantly in males in the first three decades of life. Untreated, the syndrome may persist for many years or it may be self-limiting, lasting only a few days. Occupation does not seem to be a factor predisposing to symmetric lividity of the soles. There is a high incidence of family occurrence of this condition. Any form of treatment which controls the hyperhidrosis controls the other symptoms of symmetric lividity of the soles. PMID:13364666

Nelson, Lawrence M.

1956-01-01

355

Geometric characteristics of aberrations of plane-symmetric optical systems  

SciTech Connect

The geometric characteristics of aberrations of plane-symmetric optical systems are studied in detail with a wave-aberration theory. It is dealt with as an extension of the Seidel aberrations to realize a consistent aberration theory from axially symmetric to plane-symmetric systems. The aberration distribution is analyzed with the spot diagram of a ray and an aberration curve. Moreover, the root-mean-square value and the centroid of aberration distribution are discussed. The numerical results are obtained with the focusing optics of a toroidal mirror at grazing incidence.

Lu Lijun; Deng Zhiyong

2009-12-20

356

Signature for local Mixmaster dynamics in U(1) symmetric cosmologies  

E-print Network

Previous studies \\cite{berger98a} have provided strong support for a local, oscillatory approach to the singularity in U(1) symmetric, spatially inhomogeneous vacuum cosmologies on $T^3 \\times R$. The description of a vacuum Bianchi type IX, spatially homogeneous Mixmaster cosmology (on $S^3 \\times R$) in terms of the variables used to describe the U(1) symmetric cosmologies indicates that the oscillations in the latter are in fact those of local Mixmaster dynamics. One of the variables of the U(1) symmetric models increases only at the end of a Mixmaster era. Such an increase therefore yields a qualitative signature for local Mixmaster dynamics in spatially inhomogeneous cosmologies.

Beverly K. Berger; Vincent Moncrief

2000-06-20

357

Morphological behavior spanning the symmetric AB and ABC block copolymer states  

NASA Astrophysics Data System (ADS)

The phase behavior expressed between the symmetric AB and ABC copolymer states was investigated for triblock copolymer systems differing only in the linear sequence of the same three constituent blocks: polystyrene (PS), polyisoprene (PI), and polyethylene oxide (PEO). Ten poly(styrene-b-isoprene-b-ethylene oxide) (PS-PI-PEO) and thirteen poly(isoprene-b-styrene-b-ethylene oxide) (PI-PS-PEO) triblock copolymers distributed along the same compositional isopleth (fA = fB) were characterized using a combination of small angle x-ray scattering, transmission electron microscopy, rheology, and static birefringence measurements. Differences in phase behavior exhibited by these two series of molecules are explained in terms of contrasting thermodynamic relationships imposed by the specific connectivity of each system. Only a single morphology, albeit a previously unreported non-cubic network phase, was found to span the two- and three-domain lamellar regions bounding the symmetric states in the PI-PS-PEO system. Both the simplicity of behavior and the formation of a new morphology are discussed in terms of the primary interaction parameter symmetry (chiAB ˜ chi BC) and the lack of frustration (chiAC > chiAB and chiBC in these molecules. In direct contrast, the frustration condition (chiAC < chiBC and/or chiAB ) and primary interaction parameter asymmetry (chiBC > chi AB) inherent to the PS-PI-PEO molecules was found to generate behavior of comparatively greater complexity. In this case, four distinct morphologies were identified between the two lamellar states, including core-shell analogs of the cylinder and gyroid phases, and two tentatively assigned lamellar-like structures both possessing regions of A/C interfacial contact.

Bailey, Travis Slade

358

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

SciTech Connect

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.

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

359

TOP500 Supercomputers for June 2005  

SciTech Connect

25th Edition of TOP500 List of World's Fastest Supercomputers Released: DOE/L LNL BlueGene/L and IBM gain Top Positions MANNHEIM, Germany; KNOXVILLE, Tenn.; BERKELEY, Calif. In what has become a closely watched event in the world of high-performance computing, the 25th edition of the TOP500 list of the world's fastest supercomputers was released today (June 22, 2005) at the 20th International Supercomputing Conference (ISC2005) in Heidelberg Germany.

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

2005-06-22

360

TOP500 Supercomputers for June 2004  

SciTech Connect

23rd Edition of TOP500 List of World's Fastest Supercomputers Released: Japan's Earth Simulator Enters Third Year in Top Position MANNHEIM, Germany; KNOXVILLE, Tenn.;&BERKELEY, Calif. In what has become a closely watched event in the world of high-performance computing, the 23rd edition of the TOP500 list of the world's fastest supercomputers was released today (June 23, 2004) at the International Supercomputer Conference in Heidelberg, Germany.

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

2004-06-23

361

TOP500 Supercomputers for November 2004  

SciTech Connect

24th Edition of TOP500 List of World's Fastest Supercomputers Released: DOE/IBM BlueGene/L and NASA/SGI's Columbia gain Top Positions MANNHEIM, Germany; KNOXVILLE, Tenn.; BERKELEY, Calif. In what has become a closely watched event in the world of high-performance computing, the 24th edition of the TOP500 list of the worlds fastest supercomputers was released today (November 8, 2004) at the SC2004 Conference in Pittsburgh, Pa.

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

2004-11-08

362

Top-k ranking for uncertain data  

Microsoft Academic Search

The goal of top-k ranking is to rank individuals so that the best k of them can be determined. The definition of top-k ranking is easy for certain data. But for uncertain data, the problem becomes challenging, both semantically and computationally. In this paper, we study semantic issues with top-k ranking for objects modeled by uncertain data in databases. Uncertain

Chonghai Wang; Li-Yan Yuan; Jia-Huai You

2010-01-01

363

Diversity in Biological Molecules  

ERIC Educational Resources Information Center

One of the striking characteristics of fundamental biological processes, such as genetic inheritance, development and primary metabolism, is the limited amount of variation in the molecules involved. Natural selective pressures act strongly on these core processes and individuals carrying mutations and producing slightly sub-optimal versions of…

Newbury, H. John

2010-01-01

364

Atoms, Molecules, and Ions  

NSDL National Science Digital Library

General chemistry WebCT exam/quiz questions. The Atoms, Molecules, and Ions topic covers the basics of the composition of atoms, including subatomic particles, elements, allotropes, and isotopes. Periodic placement and trends, molar mass, and molecular formulas and ions are also included.

2008-02-12

365

Sugars as signaling molecules  

Microsoft Academic Search

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

Jen Sheen; Li Zhou; Jyun-Chyun Jang

1999-01-01

366

Enforcing Molecules To Behave  

Microsoft Academic Search

The last two centuries have witnessed the growth of organic photochemistry from a relatively unknown to a developed discipline. During this period, photochemists have discovered new reac-tions, established mechanisms of photoreactions, laid out the ground rules for the behavior of mol-ecules in the excited state surfaces, and found applications of photochemistry in everyday life. In spite of these achievements, photochemistry

V. Ramamurthy

367

Heterocyclic small molecule peptidomimetics  

E-print Network

Polymer-supported synthesis of a close analog (i.e. A) of an early lead, a 14- membered ring peptidomimetic D3, was described. The monovalent molecule was attached to different length linkers, and they were then paired sequentially on a triazine...

Liu, Jing

2009-05-15

368

Halley's polymeric organic molecules  

NASA Astrophysics Data System (ADS)

The detection of polymeric organic compounds in the mass spectrum of Comet Halley obtained with the Positive Ion Cluster Composition analyzer on Giotto are examined. It is found that, in addition to polyoxymethylene, other polymers and complex molecules may exist in the comet. It is suggested that polymerized hydrogen cyanide may be a source for the observed CN and NH2 jets.

Huebner, W. F.; Boice, D. C.; Korth, A.

369

Algebraic theory of molecules  

NASA Technical Reports Server (NTRS)

An algebraic formulation of quantum mechanics is presented. In this formulation, operators of interest are expanded onto elements of an algebra, G. For bound state problems in nu dimensions the algebra G is taken to be U(nu + 1). Applications to the structure of molecules are presented.

Iachello, Franco

1995-01-01

370

Mighty Molecule Models  

ERIC Educational Resources Information Center

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…

Brown, Tom; Rushton, Greg; Bencomo, Marie

2008-01-01

371

Financial Atoms and Molecules  

Microsoft Academic Search

Atoms and molecules are important conceptual entities we invented to understand the physical world around us. The key to their usefulness lies in the organization of nuclear and electronic degrees of freedom into a single dynamical variable whose time evolution we can better imagine. The use of such effective variables in place of the true microscopic variables is possible because

Yik Wen Goo; Tong Wei Lian; Wei Guang Ong; Wen Ting Choi; Siew-Ann Cheong

2009-01-01

372

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

E-print Network

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.

U. Husemann

2008-07-29

373

Top polarization and spin correlation using top pair events in ATLAS experiment  

E-print Network

In proton-proton collisions at the LHC, pairs of top and anti-top quarks are expected to be mostly produced through gluon fusion. Making use of the large number of top quark pairs collected in the 7 TeV data, we present measurements of the spin correlation between top and anti-top quarks using several variables and discuss their sensitivity to new physics. In addition, we present measurements of the top quark polarisation predicted in models with CP-conserving and CP-violating processes. All measurements are consistent with the Standard Model predictions.

chengguang, zhu; The ATLAS collaboration

2014-01-01

374

Single Top Quarks at the Tevatron  

E-print Network

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.

A. P. Heinson

2008-09-05

375

A parallel algorithm for the non-symmetric eigenvalue problem  

SciTech Connect

This paper describes a parallel algorithm for computing the eigenvalues and eigenvectors of a non-symmetric matrix. The algorithm is based on a divide-and-conquer procedure and uses an iterative refinement technique.

Dongarra, J.; Sidani, M. (Tennessee Univ., Knoxville, TN (United States). Dept. of Computer Science Oak Ridge National Lab., TN (United States))

1991-12-01

376

Twistor spinors on Lorentzian symmetric spaces Helga Baum  

E-print Network

.Penrose in General Relativity (see [Pen67], [PR86 * *], [NW84 ]). They are related to Killing vector fields in semi Twistor spinors on Lorentzian symmetric spaces spinors has constant sectional curvature. Furthermore, each homog* *eneous Riemannian manifold

Baum, Helga

377

Symmetric Pin Diversion Detection using a Partial Defect Detector (PDET)  

SciTech Connect

Since the signature from the Partial Defect Detector (PDET) is principally dependent on the geometric layout of the guide tube locations, the capability of the technique in detecting symmetric diversion of pins needs to be determined. The Monte Carlo simulation study consisted of cases where pins were removed in a symmetric manner and the resulting signatures were examined. In addition to the normalized gamma-to-neutron ratios, the neutron and gamma signatures normalized to their maximum values, were also examined. Examination of the shape of the three curves as well as of the peak-to-valley differences in excess of the maximum expected in intact assemblies, indicated pin diversion. A set of simulations with various symmetric patterns of diversion were examined. The results from these studies indicated that symmetric diversions as low as twelve percent could be detected by this methodology.

Sitaraman, S; Ham, Y S

2009-06-01

378

Computational design of a self-assembling symmetrical ?-propeller protein.  

PubMed

The modular structure of many protein families, such as ?-propeller proteins, strongly implies that duplication played an important role in their evolution, leading to highly symmetrical intermediate forms. Previous attempts to create perfectly symmetrical propeller proteins have failed, however. We have therefore developed a new and rapid computational approach to design such proteins. As a test case, we have created a sixfold symmetrical ?-propeller protein and experimentally validated the structure using X-ray crystallography. Each blade consists of 42 residues. Proteins carrying 2-10 identical blades were also expressed and purified. Two or three tandem blades assemble to recreate the highly stable sixfold symmetrical architecture, consistent with the duplication and fusion theory. The other proteins produce different monodisperse complexes, up to 42 blades (180 kDa) in size, which self-assemble according to simple symmetry rules. Our procedure is suitable for creating nano-building blocks from different protein templates of desired symmetry. PMID:25288768

Voet, Arnout R D; Noguchi, Hiroki; Addy, Christine; Simoncini, David; Terada, Daiki; Unzai, Satoru; Park, Sam-Yong; Zhang, Kam Y J; Tame, Jeremy R H

2014-10-21

379

Toward an Efficient Column Minimum Degree Code for Symmetric Multiprocessors  

E-print Network

Toward an Efficient Column Minimum Degree Code for Symmetric Multiprocessors Tzu­Yi Chen \\Lambda machines, as well as on a Sun Enterprise 5000). We present our conclusions in Section 6. 2 Background

Chen, Tzu-Yi

380

A COMBINATORIAL CONJECTURE RELATED WITH COMPLEX BOUNDED SYMMETRIC DOMAINS  

E-print Network

GUY ROOS 1. Motivations Let be a bounded irreducible symmetric: ____________ Date: 7th November 2004. 1 #12; 2 GUY. As the function FO,~ is related to the Bergman kernel of a family of bounded (non homogeneous) domains

381

Local unitary group stabilizers and entanglement for multiqubit symmetric states  

E-print Network

We refine recent local unitary entanglement classification for symmetric pure states of $n$ qubits (that is, states invariant under permutations of qubits) using local unitary stabilizer subgroups and Majorana configurations. Stabilizer subgroups carry more entanglement distinguishing power than do the stabilizer subalgebras used in our previous work. We extend to mixed states recent results about local operations on pure symmetric states by showing that if two symmetric density operators are equivalent by a local unitary operation, then they are equivalent via a local unitary operation that is the {\\em same} in each qubit. A geometric consequence, used in our entanglement classification, is that two symmetric pure states are local unitary equivalent if and only if their Majorana configurations can be interchanged by a rotation of the Bloch sphere.

Curt D. Cenci; David W. Lyons; Scott N. Walck

2010-11-23

382

Microgrid Fault Protection Based on Symmetrical and Differential Current Components  

E-print Network

Microgrid Fault Protection Based on Symmetrical and Differential Current Components Prepared.1. SINGLE LINE-TO-GROUND (SLG) FAULTS................................................12 3.2. LINE-TO-LINE (L-TO-L) FAULTS ..............................................................14 4. PROTECTION BASED

383

Scheduling Multiple Multithreaded Applications on Asymmetric and Symmetric Chip Multiprocessors  

E-print Network

Scheduling Multiple Multithreaded Applications on Asymmetric and Symmetric Chip Multiprocessors to improve performance, fairness and jitter of workloads consisting of multiple multithreaded applications and jitter in execution runtimes when dealing with multiple multithreaded applications running in parallel

Kolodny, Avinoam

384

Scheduling Multiple Multithreaded Applications on Asymmetric and Symmetric Chip Multiprocessors  

E-print Network

Scheduling Multiple Multithreaded Applications on Asymmetric and Symmetric Chip Multiprocessors techniques to improve performance, fairness and jitter of workloads consisting of multiple multithreaded between applications and jitter in execution runtimes when dealing with multiple multithreaded

Kolodny, Avinoam

385

MHD Integrated Topping Cycle Project  

SciTech Connect

This fourteenth quarterly technical progress report of the MHD Integrated Topping Cycle Project presents the accomplishments during the period November 1, 1990 to January 31, 1991. Testing of the High Pressure Cooling Subsystem electrical isolator was completed. The PEEK material successfully passed the high temperature, high pressure duration tests (50 hours). The Combustion Subsystem drawings were CADAM released. The procurement process is in progress. An equipment specification and RFP were prepared for the new Low Pressure Cooling System (LPCS) and released for quotation. Work has been conducted on confirmation tests leading to final gas-side designs and studies to assist in channel fabrication.The final cathode gas-side design and the proposed gas-side designs of the anode and sidewall are presented. Anode confirmation tests and related analyses of anode wear mechanisms used in the selection of the proposed anode design are presented. Sidewall confirmation tests, which were used to select the proposed gas-side design, were conducted. The design for the full scale CDIF system was completed. A test program was initiated to investigate the practicality of using Avco current controls for current consolidation in the power takeoff (PTO) regions and to determine the cause of past current consolidation failures. Another important activity was the installation of 1A4-style coupons in the 1A1 channel. A description of the coupons and their location with 1A1 channel is presented herein.

Not Available

1992-02-01

386

Table-top EUV reflectometer  

NASA Astrophysics Data System (ADS)

A novel compact EUV-reflectometer recently developed is presented. The designconcept relies on a flexible approach, thus this reflectometer can be set up as a compact table-top tool for a specified task as well as a full all-purpose reflectometer. As an EUV-source an electron-based microfocus EUV-tube is used. This EUV source is debris-free and provides a typical output of 30?W at 13.5 nm. The reflectometer benefits from the very good long-time stability and spatial stability of this tube. Reflectivity measurements from grazing incidence to nearly normal incidence as well as transmission studies can be realized in the same setup at a typical precision of measurements of 0.5%. A precise computer-controlled positioning unit allows to vary and scan all important parameters online, allowing for example complex surface scans and angle variations. The concept of the reflectometer is discussed and recent results are presented. This device can be purchased from the Laser Zentrum Hannover e.V.

Hinze, U.; Chichkov, B.

2006-03-01

387

Top-of-Rail lubricant  

SciTech Connect

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.

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

2000-07-14

388

Crossing symmetric potential model of pion-nucleon scattering  

SciTech Connect

A crossing symmetric {pi}N scattering amplitude is constructed through a complete attachment of two external pions to the dressed nucleon propagator of an underlying {pi}N potential model. Our formulation automatically provides expressions also for the crossing symmetric and gauge invariant pion photoproduction and Compton scattering amplitudes. We show that our amplitudes are unitary if they coincide on-shell with the amplitudes obtained by attaching one pion to the dressed {pi}NN vertex of the same potential model.

Blankleider, B.; Skawronski, T. [School of Chemical and Physical Sciences, Flinders University, South Australia (Australia); Kvinikhidze, A. N. [Razmadze Mathematical Institute (Georgia)

2010-07-27

389

A wave refraction analysis for an axially symmetrical island  

E-print Network

A WAVE REFRACTION ANALYSIS FOR AN AXIALLY SYMMETRICAL ISLAND A Thesis By LIEUTENANT RONALD J FORST UNITED STATES NAVY Submitted to the Graduate College of the Texas A&M University in partial fulfillment of the requirements for the degree... of MASTER OF SCIENCE l966 Major Subject Oceanography A WAVE REFRACTION ANALYSIS FOR AN AXIALLY SYMMETRICAL ISLAND A Thesis By LIEUTENANT RONALD J FORST UNITED STATES NAVY Approved as to style and content by; ( airma Committee) Head of Dep rtme t...

Forst, Ronald John

2012-06-07

390

On the Averaging of Symmetric Positive-Definite Tensors  

Microsoft Academic Search

In this paper we present properly invariant averaging procedures for symmetric positive-definite tensors which are based on different measures of nearness of symmetric positive-definite tensors. These procedures intrinsically account for the positive-definite property of the tensors to be averaged. They are independent of the coordinate system, preserve material symmetries, and more importantly, they are invariant under inversion. The results of

Maher Moakher

2006-01-01

391

Linear relaxation processes governed by fractional symmetric kinetic equations  

Microsoft Academic Search

The fractional symmetric Fokker-Planck and Einstein-Smoluchowski kinetic equations that describe the evolution of systems\\u000a influenced by stochastic forces distributed with stable probability laws are derived. These equations generalize the known\\u000a kinetic equations of the Brownian motion theory and involve symmetric fractional derivatives with respect to velocity and\\u000a space variables. With the help of these equations, the linear relaxation processes in

A. V. Chechkin; V. Yu. Gonchar

2000-01-01

392

Robustness of differentiation cascades with symmetric stem cell division.  

PubMed

Stem cells (SCs) perform the task of maintaining tissue homeostasis by both self-renewal and differentiation. While it has been argued that SCs divide asymmetrically, there is also evidence that SCs undergo symmetric division. Symmetric SC division has been speculated to be key for expanding cell numbers in development and regeneration after injury. However, it might lead to uncontrolled growth and malignancies such as cancer. In order to explore the role of symmetric SC division, we propose a mathematical model of the effect of symmetric SC division on the robustness of a population regulated by a serial differentiation cascade and we show that this may lead to extinction of such population. We examine how the extinction likelihood depends on defining characteristics of the population such as the number of intermediate cell compartments. We show that longer differentiation cascades are more prone to extinction than systems with less intermediate compartments. Furthermore, we have analysed the possibility of mixed symmetric and asymmetric cell division against invasions by mutant invaders in order to find optimal architecture. Our results show that more robust populations are those with unfrequent symmetric behaviour. PMID:24718457

Sánchez-Taltavull, Daniel; Alarcón, Tomás

2014-06-01

393

TOPS Laboratory Program Management Activities Wisconsin Traffic Operations and Safety (TOPS) Laboratory  

E-print Network

TOPS Laboratory Program Management Activities Wisconsin Traffic Operations and Safety (TOPS Development 511 Traveler Information Program Management Volume Speed Occupancy (V-SPOC) Traffic Analysis and Planning Program Management Computer Aided Dispatch Advanced Traffic Management System Interface (Inter

Sheridan, Jennifer

394

7. DETAIL OF TOP CHORD/END POST CONNECTION. THE TOPS OF ...  

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

7. DETAIL OF TOP CHORD/END POST CONNECTION. THE TOPS OF BOTH MEMBERS ARE COVERED WITH SOLID PLATES. - Montgomery County Bridge No. 221, Metz Road spanning Towamencin Creek, Skippack, Montgomery County, PA

395

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

E-print Network

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

Hampton, Randy

396

CDF/PUB/TOP/PUBLIC/10793 Measurement of Single Top Quark Production  

E-print Network

quark discovery. It is still important for several reasons. Within the SM, the single-top signal allowsCDF/PUB/TOP/PUBLIC/10793 Measurement of Single Top Quark Production in 7.5 fb-1 of CDF Data Using a measurement of single top quark production in lepton plus jets final state using 7.5 fb-1 of p¯p collision

Quigg, Chris

397

Discovery of Top Quark Anton Kapliy  

E-print Network

Discovery of Top Quark Anton Kapliy University of Chicago 2008 #12;Motivation By mid review discovery of the top quark by the CDF collaboration, and then consider some exciting possibilities and D0 collaborations. The leading-order Feynman diagrams for ttbar production are2 : 1 «Discovery

398

Annual Lists of Top Selling Toys  

NSDL National Science Digital Library

To the great satisfaction of many, no doubt, Pokemon was not the top-seller in 1999, losing out to the old standards -- Crayola Crayons and Hot Wheels cars. In terms of dollar sales, however, another relative newcomer stood at the top -- Furby, but it was followed closely by Hot Wheels, a toy costing 1/33 the price.

399

The Sakai Spinner: A Paperclip Top  

ERIC Educational Resources Information Center

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 ?…

Corrao, Christian T.

2014-01-01

400

Top Managerial Prestige and Organizational Bankruptcy.  

ERIC Educational Resources Information Center

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.…

D'Aveni, Richard

1990-01-01

401

Textured soy protein (TSP) as pizza topping  

Microsoft Academic Search

Purpose – The purpose of this paper is to investigate the stability of chicken flavored textured soy protein (TSP) substitution for chicken meat in pizza toppings. Design\\/methodology\\/approach – TSP obtained from defatted soy flour was used to replace chicken at 25, 50 and 100 percent level in the pizza toppings. Patent grade wheat flour, TSP, boiled chicken, cheese, pizza shell

Ghazala Qammar; Ghulam Mohy-ud-Din; Nuzhat Huma; Ayesha Sameen; Muhammad Issa Khan

2010-01-01

402

7, 80878111, 2007 Influence of cloud top  

E-print Network

ACPD 7, 8087­8111, 2007 Influence of cloud top variability on radiative transfer Richter, Barfus under a Creative Commons License. Atmospheric Chemistry and Physics Discussions The influence of cloud.richter@awi.de) 8087 #12;ACPD 7, 8087­8111, 2007 Influence of cloud top variability on radiative transfer Richter

Paris-Sud XI, Université de

403

Method for drilling coke oven top brick  

Microsoft Academic Search

An apparatus for drilling vertical temperature measuring holes in the top brick of coke ovens includes a guide support vertically fixedly mounted on a horizontal frame on the top surface of a coke oven proper, and a guide pipe shaft connected at its upper end to a rotary drill, having a freely replaceable drilling bit attached to its lower end

Ogahara

1985-01-01

404

Tools for top physics at D0  

SciTech Connect

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.

Harel, Amnon

2008-07-01

405

Race to Top Draws out New Suitors  

ERIC Educational Resources Information Center

The list of 61 finalists for the latest Race to the Top competition shows that the U.S. Department of Education was successful in enticing high-scoring applications from districts in rural America and in states that had not shared in the Race to the Top bounty before. But whether the ultimate winners, which will be announced this month, will be…

McNeil, Michele

2012-01-01

406

Review of Top Quark Physics Results  

SciTech Connect

As the heaviest known fundamental particle, the top quark has taken a central role in the study of fundamental interactions. Production of top quarks in pairs provides an important probe of strong interactions. The top quark mass is a key fundamental parameter which places a valuable constraint on the Higgs boson mass and electroweak symmetry breaking. Observations of the relative rates and kinematics of top quark final states constrain potential new physics. In many cases, the tests available with study of the top quark are both critical and unique. Large increases in data samples from the Fermilab Tevatron have been coupled with major improvements in experimental techniques to produce many new precision measurements of the top quark. The first direct evidence for electroweak production of top quarks has been obtained, with a resulting direct determination of V{sub tb}. Several of the properties of the top quark have been measured. Progress has also been made in obtaining improved limits on potential anomalous production and decay mechanisms. This review presents an overview of recent theoretical and experimental developments in this field. We also provide a brief discussion of the implications for further efforts.

Kehoe, R.; Narain, M.; Kumar, A.; ,

2007-12-01

407

Pinch Experiments in a Table Top Generator  

SciTech Connect

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.

Pavez, Cristian; Moreno, Jose; Soto, Leopoldo [Center for Research and Applications in Plasma Physics and Pulsed Power, P4 (Chile); Comision Chilena de Energia Nuclear (Chile); Tarifeno, Ariel [Center for Research and Applications in Plasma Physics and Pulsed Power, P4 (Chile); Universidad de Concepcion (Chile)

2009-01-21

408

Measurement of the Top Quark Mass  

Microsoft Academic Search

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

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

409

Top Stars: An Opportunity for Educators  

Microsoft Academic Search

Think you're a Top Star? Want to find out what it takes? Learn about NASA's Top Stars contest and how you can participate. Throughout its lifetime, the Hubble Space Telescope has inspired and promoted education. The final Hubble servicing mission in May of this year and the celebration of Hubble's 20th anniversary in 2010 are key mission milestones, and both

S. M. P. Kinnison

2010-01-01

410

8, 1074910790, 2008 Boundary-layer top  

E-print Network

lidar, a vertical-wind Doppler lidar, and ac- companying radiosonde profiling of temperatureACPD 8, 10749­10790, 2008 Boundary-layer top from lidar H. Baars et al. Title Page Abstract Chemistry and Physics Discussions Continuous monitoring of the boundary-layer top with lidar H. Baars, A

Paris-Sud XI, Université de

411

Molecules in interstellar clouds  

NASA Astrophysics Data System (ADS)

The physical conditions and chemical compositions of the gas in interstellar clouds are reviewed in light of the importance of interstellar clouds for star formation and the origin of life. The Orion A region is discussed as an example of a giant molecular cloud where massive stars are being formed, and it is pointed out that conditions in the core of the cloud, with a kinetic temperature of about 75 K and a density of 100,000-1,000,000 molecules/cu cm, may support gas phase ion-molecule chemistry. The Taurus Molecular Clouds are then considered as examples of cold, dark, relatively dense interstellar clouds which may be the birthplaces of solar-type stars and which have been found to contain the heaviest interstellar molecules yet discovered. The molecular species identified in each of these regions are tabulated, including such building blocks of biological monomers as H2O, NH3, H2CO, CO, H2S, CH3CN and H2, and more complex species such as HCOOCH3 and CH3CH2CN.

Irvine, W. M.; Hjalmarson, A.; Rydbeck, O. E. H.

412

Multiplexed single molecule immunoassays.  

PubMed

We have developed a method that enables the multiplexed detection of proteins based on counting single molecules. Paramagnetic beads were labeled with fluorescent dyes to create optically distinct subpopulations of beads, and antibodies to specific proteins were then immobilized to individual subpopulations. Mixtures of subpopulations of beads were then incubated with a sample, and specific proteins were captured on their specific beads; these proteins were then labeled with enzymes via immunocomplex formation. The beads were suspended in enzyme substrate, loaded into arrays of femtoliter wells--or Single Molecule Arrays (Simoa)--that were integrated into a microfluidic device (the Simoa disc). The wells were then sealed with oil, and imaged fluorescently to determine: a) the location and subpopulation identity of individual beads in the femtoliter wells, and b) the presence or absence of a single enzyme associated with each bead. The images were analyzed to determine the average enzyme per bead (AEB) for each bead subpopulation that provide a quantitative parameter for determining the concentration of each protein. We used this approach to simultaneously detect TNF-?, IL-6, IL-1?, and IL-1? in human plasma with single molecule resolution at subfemtomolar concentrations, i.e., 200- to 1000-fold more sensitive than current multiplexed immunoassays. The simultaneous, specific, and sensitive measurement of several proteins using multiplexed digital ELISA could enable more reliable diagnoses of disease. PMID:23719780

Rissin, David M; Kan, Cheuk W; Song, Linan; Rivnak, Andrew J; Fishburn, Matthew W; Shao, Qichao; Piech, Tomasz; Ferrell, Evan P; Meyer, Raymond E; Campbell, Todd G; Fournier, David R; Duffy, David C

2013-08-01

413

Thermionic topping of electric power plants  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

414

Top Quark Precision Physics at Linear Colliders  

E-print Network

Linear e+e- colliders provide a rich set of opportunities for precision top physics, crucial for the understanding of electroweak symmetry breaking and for the search for physics beyond the Standard Model. A ttbar threshold scan in e+e- annihilation enables a precise measurement in theoretically well-defined mass schemes with small experimental and theoretical systematic uncertainties. Above the production threshold, the ecient identification of top pair events combined with polarized beams provides the potential to extract the form factors for the top quark couplings with high precision and in a model-independent way, resulting in excellent sensitivity to physics beyond the Standard Model. This contribution provides an overview of top physics at linear colliders based on results from full-simulation studies of top quark pair production in the detectors proposed for ILC and CLIC.

Simon, F.

2014-01-01

415

D{O} top quark mass analysis  

SciTech Connect

Based on (44-48 pb{sup -1}) of lepton + jets data, we review D0`s initial analysis of the top quark mass. The result, M{sub top} = 199 {+-} 19/21 (stat.) {+-} 22 (syst.) GeV/c{sup 2}, is insensitive to background normalization. The errors are based on ISAJET top Monte Carlo, with its more severe gluon radiation, and allow for ISAJET/HERWIG differences. Good progress is being made in reducing the systematic error. We present a new study based on two-dimensional distributions of reconstructed top quark vs. dijet mass. With 98.7% confidence we observe a peak in the top mass - dijet mass plane. The peak and its projections are similar both in shape and magnitude to expectations based on the decay sequence 1 {yields} bW, W {yields} jj.

Strovink, M.

1995-07-01

416

MBA WOMEN INTERNATIONAL VIRTUAL SPRING CAREER FAIR Connecting Top Talent with Top Employers Nationwide!  

E-print Network

MBA WOMEN INTERNATIONAL VIRTUAL SPRING CAREER FAIR Connecting Top Talent with Top Employers leading employers with top women talent -- enriching workforce diversity around the world. REGISTER TODAY of capabilities and talents! VISIT US ONLINE www.mbawomen.org ATTENDANCE INCLUDES Powered by Brazen Careerist

Massachusetts at Lowell, University of

417

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

PubMed Central

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

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

2009-01-01

418

Negative ions of polyatomic molecules.  

PubMed Central

In this paper general concepts relating to, and recent advances in, the study of negative ions of polyatomic molecules area discussed with emphasis on halocarbons. The topics dealt with in the paper are as follows: basic electron attachment processes, modes of electron capture by molecules, short-lived transient negative ions, dissociative electron attachment to ground-state molecules and to "hot" molecules (effects of temperature on electron attachment), parent negative ions, effect of density, nature, and state of the medium on electron attachment, electron attachment to electronically excited molecules, the binding of attached electrons to molecules ("electron affinity"), and the basic and the applied significance of negative-ion studies. PMID:7428744

Christophorou, L G

1980-01-01

419

A Symmetrical Tetramer for S. aureus Pyruvate Carboxylase in Complex with Coenzyme A  

SciTech Connect

Pyruvate carboxylase (PC) is a conserved metabolic enzyme with important cellular functions. We report crystallographic and cryo-electron microscopy (EM) studies of Staphylococcus aureus PC (SaPC) in complex with acetyl-CoA, an allosteric activator, and mutagenesis, biochemical, and structural studies of the biotin binding site of its carboxyltransferase (CT) domain. The disease-causing A610T mutation abolishes catalytic activity by blocking biotin binding to the CT active site, and Thr908 might play a catalytic role in the CT reaction. The crystal structure of SaPC in complex with CoA reveals a symmetrical tetramer, with one CoA molecule bound to each monomer, and cryo-EM studies confirm the symmetrical nature of the tetramer. These observations are in sharp contrast to the highly asymmetrical tetramer of Rhizobium etli PC in complex with ethyl-CoA. Our structural information suggests that acetyl-CoA promotes a conformation for the dimer of the biotin carboxylase domain of PC that might be catalytically more competent.

Yu, L.; Xiang, S; Lasso, G; Gil, D; Valle, M; Tong, L

2009-01-01

420

Invisible dark gauge boson search in top decays using a kinematic method  

E-print Network

We discuss the discovery potential of a dark force carrier ($Z'$) of very light mass, $m_{Z'} \\lesssim {\\cal O}(1-10)$ GeV, at hadron colliders via rare top quark decays, especially when it decays invisibly in typical search schemes. We emphasize that the top sector is promising for the discovery of new particles because top quark pairs are copiously produced at the Large Hadron Collider. The signal process is initiated by a rare top decay into a bottom quark and a charged Higgs boson ($H^\\pm$) decaying subsequently into a $W$ and one or multiple $Z'$s. The light $Z'$ can be invisible in collider searches in various scenarios, and it would be hard to distinguish the relevant collider signature from the regular $t\\bar{t}$ process in the Standard Model. We suggest a search strategy using the recently proposed on-shell constrained $M_2$ variables. Our signal process is featured by an $\\textit{asymmetric}$ event topology, while the $t\\bar{t}$ is $\\textit{symmetric}$. The essence behind the strategy is to evoke so...

Kim, Doojin; Park, Myeonghun

2014-01-01

421

Discovery of single top quark production  

SciTech Connect

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.

Gillberg, Dag

2009-05-01

422

Synthesis and chiroptical properties of chiral azoaromatic dendrimers with a C3-symmetrical core.  

PubMed

New chiral azoaromatic dendrimeric systems have been synthesized starting from 1,3,5-benzenetricarbonyl trichloride as the core molecule. The simultaneous presence of the (S)-3-hydroxy pyrrolidinyl ring as the optically active moiety and the azobenzene donor-acceptor conjugated system as the photochromic group with permanent dipole moment, makes these systems potentially interesting as materials for advanced applications in nanotechnologies. All the compounds obtained have been characterized with particular attention to the effects induced by changing the electron-withdrawing group in the chromophoric moiety and to their optical activity. A strong nonlinear enhancement of chiroptical properties related to the number of chiral units linked to the symmetrical core is observed in these derivatives, which indicates the presence of conformationally chiral substructures. PMID:19387991

Angiolini, Luigi; Benelli, Tiziana; Giorgini, Loris

2010-01-01

423

29Counting Atoms in a Molecule The complex molecule Propanal  

E-print Network

29Counting Atoms in a Molecule The complex molecule Propanal was discovered in a dense interstellar is the ratio of carbon atoms to hydrogen atoms in propanal? Problem 4 - If the mass of a hydrogen atom of a propanal molecule in AMUs? Problem 5 - What is the complete chemical formula for propanal? C3 H __ O

424

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

425

Rotationally induced nuclear quadrupole coupling in spherical-top molecules 2014  

E-print Network

to 189OsO4 M. L. Palma and J. Bordé Laboratoire de Spectroscopie Moléculaire (*), Université Pierre gradient du champ élec- trique par rapport aux coordonnées normales. Pour 189OsO4, nous comparons l-induced and vibration-induced coupling is discussed for189OsO4 ; the use of spin-vibration-rotation interaction

Paris-Sud XI, Université de

426

Semiexperimental equilibrium structure of the oblate-top molecules dimethyl sulfoxide and cyclobutene  

NASA Astrophysics Data System (ADS)

A semiexperimental equilibrium structure is derived for dimethyl sulfoxide and cyclobutene from experimental ground-state rotational constants and rovibrational interaction parameters calculated from the ab initio cubic force field. In the case of dimethyl sulfoxide, the presence of several small Cartesian coordinates as well large rotations of the principal axis system upon isotopic substitution hamper an accurate determination of the structure. To achieve an accurate structure, the mixed estimation method is used. In this method, internal coordinates of good quality quantum chemical calculations (with appropriate uncertainty) are fitted simultaneously with the semiexperimental moments of inertia of all isotopomers. On the other hand, there was no difficulty to get an accurate semiexperimental structure for cyclobutene because there are neither small coordinates nor large rotations of the principal axis system.

Vogt, Natalja; Demaison, Jean; Rudolph, Heinz Dieter

2014-03-01

427

Deuterium in North Atlantic storm tops  

SciTech Connect

During the ERICA project in 1989, ice crystals were collected from the tops of two winter storms and one broad cirrus cloud. Deuterium concentration in the storm ice samples, together with a model of isotope fractionation, are used to determine the temperature where the ice was formed. Knowledge of the ice formation temperature allows us to determine whether the ice has fallen or been lofted to the altitude of collection. In both storms, the estimated fall distance decreases upward. In the 21 January storm, the fall distance decreases to zero at the cloud top. In the 23 January storm, the fall distance decreases to zero at a point 2 km below the cloud top and appears to become negative above, indicating lofted ice. Cloud particle data from the cloud tops show an ice-to-vapor ratio greater than one and indicate the presence of particles with small terminal velocities; both observations support the idea of ice lofting. The satellite-derived cloud tops lie well below the actual cloud top (e.g., 2.5 km below on 23 January), indicating that the lofted ice in winter storms may not be detectable from space using IR radiance techniques. A comparison of deuterium in cloud-top ice and clear-air vapor suggests that even in winter, when vertical air motions are relatively weak, lofted ice crystals are the dominant source of water vapor in the upper troposphere. 28 refs.

Smith, R.B. (Yale Univ., New Haven, CT (United States))

1992-11-01

428

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

E-print Network

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.

Peters, Reinhild Yvonne; CDF,; CMS,

2014-01-01

429

Experimental investigation of soliton molecules  

Microsoft Academic Search

Detailed experimental investigations of the recently discovered temporal soliton molecules are reported. The optical fiber length was now extended; thus stable and unstable regimes of the soliton molecule can be distinguished from another more precisely.

H. Hartwig; M. Stratmann; F. Mitschke

2006-01-01

430

Approximate Noether Symmetries from Lagrangian for Plane Symmetric Spacetimes  

E-print Network

Noether symmetries from geodetic Lagrangian for time-conformal plane symmetric spacetime are presented. Here, time conformal factor is used to find the approximate Noether symmetries. This is a generalization of the idea discussed by I. Hussain and A. Noether symmetries from geodetic Lagrangian for time-conformal plane symmetric spacetime are presented. Here, time conformal factor is used to find the approximate Noether symmetries. This is a generalization of the idea discussed by I. Hussain and A. Qadir [3,4], where they obtained approximate Noether symmetries from Lagrangian for a particular plane symmetric static spacetime. In the present article, the most general plane symmetric static spacetime is considered and perturb it by introducing a general time conformal factor $e^{\\epsilon f(t)}$, where $\\epsilon$ is very small which causes the perturbation in the spacetime. Taking the perturbation up to the first order, we find all Lagrangian for plane symmetric spactimes from which approximate Noether symmetries exist. PACS 11.30.-j-Symmetries and conservation laws PACS 04.20.-q-Classical general Relativity

Farhad Ali; Tooba Feroze

2014-11-07

431

Synthesis and evaluation of cumulenes: novel rigid nonlinear optical molecules  

NASA Astrophysics Data System (ADS)

We report our investigations of the cumulenes, a novel class of compounds proposed for use as the active second- and thirdorder nonlinear optical component materials for electro-optic and all-optical devices. Unlike conjugated organic nonlinear optical molecules based on alternating multiple and single bonds, these molecules contain a contiguous, or "cumulated" system of double bonds, leading to a highly rigid one-dimensional backbone of polarizable ic-electrons. A series of symmetrically- and asymmetrically-substituted teiraphenyl cumulenes has been synthesized and characterized. D.C. electric field-induced second harmonic generation experiments show significant second-order nonlinear susceptibilities in a series of polar cumulenes. Preliminary results showing evidence of resonant and nonresonant third-order nonlinear optical activity are also reported.

Ermer, Susan P.; Lovejoy, Steven M.; Leung, Doris S.; Altman, Joseph C.; Aron, Kenneth P.; Spitzer, Ronnie C.; Hansen, Glenn A.

1990-12-01

432

Top quark properties from the Tevatron  

SciTech Connect

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.

Klute, Markus; /MIT, LNS

2006-05-01

433

Top-quark mass at hadron colliders  

E-print Network

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.

Andrea Castro

2014-04-14

434

Top-quark mass at hadron colliders  

NASA Astrophysics Data System (ADS)

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.

Castro, Andrea

2014-08-01

435

Hadronization systematics and top mass reconstruction  

E-print Network

I discuss a few issues related to the systematic error on the top mass measurement at hadron colliders, due to hadronization effects. Special care is taken about the impact of bottom-quark fragmentation in top decays, especially on the reconstruction relying on final states with leptons and J/psi in the dilepton channel. I also debate the relation between the measured mass and its theoretical definition, and report on work in progress, based on the Monte Carlo simulation of fictitious top-flavoured hadrons, which may shed light on this issue and on the hadronization systematics.

Gennaro Corcella

2014-09-30

436

Precision Determination of the Top Quark Mass  

SciTech Connect

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}.

Movilla Fernandez, Pedro A.; /LBL, Berkeley

2007-05-01

437

Top Quark Properties from the Tevatron  

E-print Network

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.

M. Klute

2006-05-15

438

Single Top Production at the Tevatron  

SciTech Connect

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.

Wu, Zhenbin; /Baylor U.

2012-05-01

439

Top quark mass measurement at the Tevatron  

SciTech Connect

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.

Guimaraes da Costa, Joao; /Harvard U.

2004-12-01

440

Anomalous Top-Higgs Couplings and Top Polarisation in Single Top and Higgs Associated Production at the LHC  

E-print Network

In this paper, we put constraints on anomalous $\\mathcal{CP}$-violating top-Higgs couplings using the currently available Higgs data and explore the prospect of measuring these couplings at 240 GeV TLEP. We find that the $\\mathcal{CP}$-violating phase $\\xi$ is currently limited in the range $|\\xi|xi| xi =0$), pseudoscalar ($\\xi =0.5\\pi$) and mixed ($\\xi =0.25\\pi$) top-Higgs interactions through the channel $pp \\to t(\\to \\ell^+\

Kobakhidze, Archil; Yue, Jason

2014-01-01

441

Anomalous Top-Higgs Couplings and Top Polarisation in Single Top and Higgs Associated Production at the LHC  

E-print Network

In this paper, we put constraints on anomalous $\\mathcal{CP}$-violating top-Higgs couplings using the currently available Higgs data and explore the prospect of measuring these couplings at 240 GeV TLEP. We find that the $\\mathcal{CP}$-violating phase $\\xi$ is currently limited in the range $|\\xi|xi| xi =0$), pseudoscalar ($\\xi =0.5\\pi$) and mixed ($\\xi =0.25\\pi$) top-Higgs interactions through the channel $pp \\to t(\\to \\ell^+\

Archil Kobakhidze; Lei Wu; Jason Yue

2014-06-08

442

New and emerging drug molecules against obesity.  

PubMed

Obesity has become a growing pandemic of alarming proportions in the developed and developing countries over the last few decades. The most perturbing fact regarding obesity is the increased predisposition for coronary artery disease, congestive heart failure and sudden cardiac death. The modest efficacy of current anti-obesity agents such as orlistat and the increasing withdrawals of several anti-obesity agents such as sibutramine, rimonabant have led to huge gaps in the pharmacotherapy of obesity. Lorcaserin and Phentermine-topiramate combination (phen-top) are two drugs approved by US FDA in 2012. Lorcaserin, a 5HT2C agonist has moderate efficacy with an acceptable safety profile. Clinical trials with Phen-top have shown a reasonable efficacy but at the cost of risks such as teratogenicity and psychiatric disturbances. Cetilistat, a lipase inhibitor is claimed to have superior safety profile to orlistat and is in phase 3 clinical trials. Other promising anti-obesity molecules acting on the gut which are in clinical trials include exenatide and liraglutide. Drugs which act on the monoaminergic and opioid systems include bupropion-naltrexone and bupropion-zonisamide. Other novel first-in-class drugs which have been explored and have limited success in early clinical development include velneperit, tesofensine, and beloranib. Tesofensine is a triple monoamine re-uptake inhibitor, velneperit acts as a neuropeptide Y5 receptor antagonist and beloranib is a methionine amino peptidase 2 inhibitor. Novel targets such as histamine H3 receptor, VEGF, matrix-metalloproteinase, sirtuin receptors are also being investigated. This review is an attempt to describe the new and emerging molecules that are in clinical development for obesity. PMID:24064009

George, Melvin; Rajaram, Muthukumar; Shanmugam, Elangovan

2014-01-01

443

Influence of fluorine substituent on the mesomorphic properties of five-ring ester banana-shaped molecules  

Microsoft Academic Search

The synthesis and characterization of more than a hundred achiral compounds composed of banana-shaped molecules and belonging to eleven different homologous series are reported. All these symmetrical five-ring compounds are esters and are derived from resorcinol. The compounds have been systematically substituted by fluorine on the phenyl rings of the arms of these banana-shaped molecules. The mesophases exhibited by these

R. Amaranatha Reddy

2003-01-01

444

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.

445

Chemical Biology of Small Molecules  

E-print Network

Chemical Biology of Small Molecules Schroeder Group Boyce Thompson Institute NH N N O NH2 N O OHO;Small molecules are important But the metabolome is underexplored Structure FunctionComparative metabolomics enables discovery of small molecule structure and function without purification #12;2D NMR

Pawlowski, Wojtek

446

Playing with molecules.  

PubMed

Recent philosophy of science has seen a number of attempts to understand scientific models by looking to theories of fiction. In previous work, I have offered an account of models that draws on Kendall Walton's 'make-believe' theory of art. According to this account, models function as 'props' in games of make-believe, like children's dolls or toy trucks. In this paper, I assess the make-believe view through an empirical study of molecular models. I suggest that the view gains support when we look at the way that these models are used and the attitude that users take towards them. Users' interaction with molecular models suggests that they do imagine the models to be molecules, in much the same way that children imagine a doll to be a baby. Furthermore, I argue, users of molecular models imagine themselves viewing and manipulating molecules, just as children playing with a doll might imagine themselves looking at a baby or feeding it. Recognising this 'participation' in modelling, I suggest, points towards a new account of how models are used to learn about the world, and helps us to understand the value that scientists sometimes place on three-dimensional, physical models over other forms of representation. PMID:22332319

Toon, Adam

2011-12-01

447

Radiative stabilization of symmetric 4l4l[prime] and non-symmetric 3l14l[prime] states in O[sup 6+  

SciTech Connect

We present calculations of energies, autoionization and radiative decay rates for symmetric 4l4l[prime] and non-symmetric 3l14l[prime] states in O[sup 6+]. Our results support an interpretation of the recent observation of radiative stabilization in double-electron capture based on the natural diversity of the decay rates between the individual terms in symmetric and quasi-symmetric configurations.

Vaeck, N.; van der Hart, H.W.; Hansen, J.E. (Van der Waals-Zeeman Laboratory, University of Amsterdam, Valckenierstraat 65, NL-1018 XE Amsterdam (Netherlands))

1993-06-05

448

Solution of generalized shifted linear systems with complex symmetric matrices  

NASA Astrophysics Data System (ADS)

We develop the shifted COCG method [R. Takayama, T. Hoshi, T. Sogabe, S.-L. Zhang, T. Fujiwara, Linear algebraic calculation of Green's function for large-scale electronic structure theory, Phys. Rev. B 73 (165108) (2006) 1-9] and the shifted WQMR method [T. Sogabe, T. Hoshi, S.-L. Zhang, T. Fujiwara, On a weighted quasi-residual minimization strategy of the QMR method for solving complex symmetric shifted linear systems, Electron. Trans. Numer. Anal. 31 (2008) 126-140] for solving generalized shifted linear systems with complex symmetric matrices that arise from the electronic structure theory. The complex symmetric Lanczos process with a suitable bilinear form plays an important role in the development of the methods. The numerical examples indicate that the methods are highly attractive when the inner linear systems can efficiently be solved.

Sogabe, Tomohiro; Hoshi, Takeo; Zhang, Shao-Liang; Fujiwara, Takeo

2012-07-01

449

Violation of Invariance of Entanglement Under Local PT Symmetric Unitary  

E-print Network

Entanglement is one of the key feature of quantum world and any entanglement measure must satisfy some basic laws. Most important of them is the invariance of entanglement under local unitary operations. We show that this is no longer true with local ${\\cal {PT}}$ symmetric unitary operations. If two parties share a maximally entangled state, then under local ${\\cal {PT}}$ symmetric unitary evolution the entropy of entanglement for pure bipartite states does not remain invariant. Furthermore, we show that if one of the party has access to ${\\cal {PT}}$-symmetric quantum world, then a maximally entangled state in usual quantum theory appears as a non-maximally entangled states for the other party. This we call as the "entanglement mismatch" effect which can lead to the violation of the no-signaling condition.

Arun Kumar Pati

2014-04-24

450

Size-independent symmetric division in extraordinarily long cells  

PubMed Central

Two long-standing paradigms in biology are that cells belonging to the same population exhibit little deviation from their average size and that symmetric cell division is size limited. Here, ultrastructural, morphometric and immunocytochemical analyses reveal that two Gammaproteobacteria attached to the cuticle of the marine nematodes Eubostrichus fertilis and E. dianeae reproduce by constricting a single FtsZ ring at midcell despite being 45??m and 120??m long, respectively. In the crescent-shaped bacteria coating E. fertilis, symmetric FtsZ-based fission occurs in cells with lengths spanning one order of magnitude. In the E. dianeae symbiont, formation of a single functional FtsZ ring makes this the longest unicellular organism in which symmetric division has ever been observed. In conclusion, the reproduction modes of two extraordinarily long bacterial cells indicate that size is not the primary trigger of division and that yet unknown mechanisms time the localization of both DNA and the septum. PMID:25221974

Pende, Nika; Leisch, Nikolaus; Gruber-Vodicka, Harald R.; Heindl, Niels R.; Ott, Jorg; den Blaauwen, Tanneke; Bulgheresi, Silvia

2014-01-01

451

Plane symmetric thin-shell wormholes: Solutions and stability  

NASA Astrophysics Data System (ADS)

Using the cut-and-paste procedure, we construct static and dynamic, plane symmetric wormholes by surgically grafting together two spacetimes of plane symmetric vacuum solutions with a negative cosmological constant. These plane symmetric wormholes can be interpreted as domain walls connecting different universes, having planar topology, and upon compactification of one or two coordinates, cylindrical topology or toroidal topology, respectively. A stability analysis is carried out for the dynamic case by taking into account specific equations of state, and a linearized stability analysis around static solutions is also explored. It is found that thin-shell wormholes made of a dark energy fluid or of a cosmological constant fluid are stable, while thin-shell wormholes made of phantom energy are unstable.

Lemos, José P. S.; Lobo, Francisco S. N.

2008-08-01

452

Ranking benchmarks of top 100 players in men's professional tennis  

Microsoft Academic Search

In men's professional tennis, players aspire to hold the top ranking position. On the way to the top spot, reaching the top 100 can be seen as a significant career milestone. National Federations undertake extensive efforts to assist their players to reach the top 100. However, objective data considering reasonable ranking yardsticks for top 100 success in men's professional tennis

Machar Reid; Craig Morris

2011-01-01

453

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

PubMed

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

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

454

Trust tops gay-friendly award list.  

PubMed

Central and North West London NHS Foundation Trust, which provides mental health, sexual health and addiction services, has been named the top performing gay-friendly healthcare organisation in England by equality charity Stonewall this week. PMID:24617366

455

Selling Energy Conservation Projects to Top Management  

E-print Network

A guide to presenting proposals on Energy Conservation Projects by plant engineers to their top level management, in order to get approval for Energy Conservation Projects. Through the author's past experience he ascertained that many Energy...

Jonsson, K. A.

1983-01-01

456

Top Ten Technology Breakthroughs for Schools.  

ERIC Educational Resources Information Center

Contributors discuss the top ten technologies that allow for thinking in new and innovative ways about the concept of "school": virtual learning; wireless networking; collaboration tools; digital video; Application Service Providers; handheld devices; optical networking; videoconferencing; XML; and simulations. (AEF)

Bateman, Bill; Crystal, Jerry; Davidson, Hall; Holzberg, Carol S.; McIntire, Todd; McLester, Susan; Ohler, Jason; Rose, Ray; Shields, Jean; Warlick, David

2001-01-01

457

Symmetric vs. asymmetric stem cell divisions: an adaptation against cancer?  

PubMed

Traditionally, it has been held that a central characteristic of stem cells is their ability to divide asymmetrically. Recent advances in inducible genetic labeling provided ample evidence that symmetric stem cell divisions play an important role in adult mammalian homeostasis. It is well understood that the two types of cell divisions differ in terms of the stem cells' flexibility to expand when needed. On the contrary, the implications of symmetric and asymmetric divisions for mutation accumulation are still poorly understood. In this paper we study a stochastic model of a renewing tissue, and address the optimization problem of tissue architecture in the context of mutant production. Specifically, we study the process of tumor suppressor gene inactivation which usually takes place as a consequence of two "hits", and which is one of the most common patterns in carcinogenesis. We compare and contrast symmetric and asymmetric (and mixed) stem cell divisions, and focus on the rate at which double-hit mutants are generated. It turns out that symmetrically-dividing cells generate such mutants at a rate which is significantly lower than that of asymmetrically-dividing cells. This result holds whether single-hit (intermediate) mutants are disadvantageous, neutral, or advantageous. It is also independent on whether the carcinogenic double-hit mutants are produced only among the stem cells or also among more specialized cells. We argue that symmetric stem cell divisions in mammals could be an adaptation which helps delay the onset of cancers. We further investigate the question of the optimal fraction of stem cells in the tissue, and quantify the contribution of non-stem cells in mutant production. Our work provides a hypothesis to explain the observation that in mammalian cells, symmetric patterns of stem cell division seem to be very common. PMID:24204602

Shahriyari, Leili; Komarova, Natalia L

2013-01-01

458

Multiqubit symmetric states with maximally mixed one-qubit reductions  

NASA Astrophysics Data System (ADS)

We present a comprehensive study of maximally entangled symmetric states of arbitrary numbers of qubits in the sense of the maximal mixedness of the one-qubit reduced density operator. A general criterion is provided to easily identify whether given symmetric states are maximally entangled in that respect or not. We show that these maximally entangled symmetric (MES) states are the only symmetric states for which the expectation value of the associated collective spin of the system vanishes, as well as in corollary the dipole moment of the Husimi function. We establish the link between this kind of maximal entanglement, the anticoherence properties of spin states, and the degree of polarization of light fields. We analyze the relationship between the MES states and the classes of states equivalent through stochastic local operations with classical communication (SLOCC). We provide a nonexistence criterion of MES states within SLOCC classes of qubit states and show in particular that the symmetric Dicke state SLOCC classes never contain such MES states, with the only exception of the balanced Dicke state class for even numbers of qubits. The 4-qubit system is analyzed exhaustively and all MES states of this system are identified and characterized. Finally the entanglement content of MES states is analyzed with respect to the geometric and barycentric measures of entanglement, as well as to the generalized N-tangle. We show that the geometric entanglement of MES states is ensured to be larger than or equal to 1/2, but also that MES states are not in general the symmetric states that maximize the investigated entanglement measures.

Baguette, D.; Bastin, T.; Martin, J.

2014-09-01

459

Symmetric vs. Asymmetric Stem Cell Divisions: An Adaptation against Cancer?  

PubMed Central

Traditionally, it has been held that a central characteristic of stem cells is their ability to divide asymmetrically. Recent advances in inducible genetic labeling provided ample evidence that symmetric stem cell divisions play an important role in adult mammalian homeostasis. It is well understood that the two types of cell divisions differ in terms of the stem cells' flexibility to expand when needed. On the contrary, the implications of symmetric and asymmetric divisions for mutation accumulation are still poorly understood. In this paper we study a stochastic model of a renewing tissue, and address the optimization problem of tissue architecture in the context of mutant production. Specifically, we study the process of tumor suppressor gene inactivation which usually takes place as a consequence of two “hits”, and which is one of the most common patterns in carcinogenesis. We compare and contrast symmetric and asymmetric (and mixed) stem cell divisions, and focus on the rate at which double-hit mutants are generated. It turns out that symmetrically-dividing cells generate such mutants at a rate which is significantly lower than that of asymmetrically-dividing cells. This result holds whether single-hit (intermediate) mutants are disadvantageous, neutral, or advantageous. It is also independent on whether the carcinogenic double-hit mutants are produced only among the stem cells or also among more specialized cells. We argue that symmetric stem cell divisions in mammals could be an adaptation which helps delay the onset of cancers. We further investigate the question of the optimal fraction of stem cells in the tissue, and quantify the contribution of non-stem cells in mutant production. Our work provides a hypothesis to explain the observation that in mammalian cells, symmetric patterns of stem cell division seem to be very common. PMID:24204602

Shahriyari, Leili; Komarova, Natalia L.

2013-01-01

460

Health Data Management top 10 special report.  

PubMed

The top 10 health care information technology companies control only about 30% of the software market. Because these leading companies do not yet dominate the market, observers predict vendors will continue to consolidate. In this in-depth special report, Health Data Management profiles the 10 leading companies, ranked on their 1996 revenues. Each corporate profile offers insights from top company executives about their strategies, as well as comments from stock analysts. PMID:10167252

Bazzoli, F; McCormack, J

1997-05-01

461

ELETTRA TOP UP REQUIREMENTS AND DESIGN STATUS  

Microsoft Academic Search

Elettra is a 2.5 GeV third generation light source in operation since 1993. To provide more stable beams to the users, we plan to operate in the so called top up injection mode. The present paper will report on the requirements for the top up operation in terms of radiation safety, diagnostics H\\/S, timing, modality and the design status.

F. Iazzourene; S. Bassanese; A. Carniel; K. Casarin; R. De Monte; M. Ferianis; F. Giacuzzo

462

Tools for top physics at CDF  

SciTech Connect

The authors describe here the different tools used for top physics analysis in the CDF Collaboration. In particular, they discuss how the jet energy scale, lepton identification, b tagging algorithms and the neural networks help to improve the signal to background ratio of the top sample in some cases and to reduce the dominant uncertainties in other. Results using each one of these tools are also presented.

Palencia, E.; /Fermilab

2008-07-01

463

Review of Tevatron Results: Top quark physics  

E-print Network

We present results on top quark physics from the CDF and D0 collaborations at the Fermilab Tevatron proton anti-proton collider. These include legacy results from Run II that were published or submitted for publication before mid-2014, as well as a summary of Run I results. The historical perspective of the discovery of the top quark in Run I is also described.

Gerber, Cecilia E

2014-01-01

464

Evidence for production of single top quarks  

E-print Network

We present first evidence for the production of single top quarks in the D0 detector at the Fermilab Tevatron ppbar 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 in pair production in 1995, and since then, single top quark production has been searched for in ever larger datasets. In this analysis, we select events from a 0.9 fb-1 dataset that have an electron or muon and missing transverse energy from the decay of a W boson from the top quark decay, and two, three, or four jets, with one or two of the jets identified as originating from a b hadron decay. The selected events are mostly backgrounds such as W+jets and ttbar events, which we separate from the expected signals using three multivariate analysis techniques: boosted decision trees, Bayesian neural networks, and matrix element calculations. A binned likelihood fit of the signal cross section plus background to the data from the combination of the results from the three analysis methods gives a cross section for single top quark production of 4.7 +- 1.3 pb. The probability to measure a cross section at this value or higher in the absence of signal is 0.014%, corresponding to a 3.6 standard deviation significance. The measured cross section value is compatible at the 10% level with the standard model prediction for electroweak top quark production.

D0 Collaboration

2008-03-05

465

The discovery of the top quark  

Microsoft Academic Search

Evidence for pair production of a new particle consistent with the standard-model top quark has been reported recently by groups studying proton-antiproton collisions at 1.8 TeV center-of-mass energy at the Fermi National Accelerator Laboratory. This paper both reviews the history of the search for the top quark in electron-positron and proton-antiproton collisions and reports on a number of precise electroweak

Claudio Campagnari; Melissa Franklin

1997-01-01

466

Lambertian white top-emitting organic light emitting device with carbon nanotube cathode  

NASA Astrophysics Data System (ADS)

We demonstrate that white organic light emitting devices (OLEDs) with top carbon nanotube (CNT) electrodes show almost no microcavity effect and exhibit essentially Lambertian emission. CNT top electrodes were applied by direct lamination of multiwall CNT sheets onto white small molecule OLED stack. The devices show an external quantum efficiency of 1.5% and high color rendering index of 70. Due to elimination of the cavity effect, the devices show good color stability for different viewing angles. Thus, CNT electrodes are a viable alternative to thin semitransparent metallic films, where the strong cavity effect causes spectral shift and non-Lambertian angular dependence. Our method of the device fabrication is simple yet effective and compatible with virtually any small molecule organic semiconductor stack. It is also compatible with flexible substrates and roll-to-roll fabrication.

Freitag, P.; Zakhidov, Al. A.; Luessem, B.; Zakhidov, A. A.; Leo, K.

2012-12-01

467

Multigrid convergence of an implicit symmetric relaxation scheme  

NASA Technical Reports Server (NTRS)

The multigrid method has been applied to an existing three-dimensional compressible Euler solver to accelerate the convergence of the implicit symmetric relaxation scheme. This lower-upper symmetric Gauss-Seidel implicit scheme is shown to be an effective multigrid driver in three dimensions. A grid refinement study is performed including the effects of large cell aspect ratio meshes. Performance figures of the present multigrid code on Cray computers including the new C90 are presented. A reduction of three orders of magnitude in the residual for a three-dimensional transonic inviscid flow using 920 k grid points is obtained in less than 4 min on a Cray C90.

Yoon, Seokkwan; Kwak, Dochan

1994-01-01

468

From Consensus to Robust Randomized Algorithms: A Symmetrization Approach  

E-print Network

This paper interprets and generalizes consensus-type algorithms as switching dynamics leading to symmetrization with respect to the actions of a finite group. Explicit convergence results are provided in a group-theoretic formulation, both for deterministic and for stochastic dynamics. We show how the symmetrization framework directly extends the scope of consensus-type algorithms and results to applications as diverse as consensus on probability distributions (either classical or quantum), computation of the discrete Fourier transform, uniform random state generation, and open-loop disturbance rejection by quantum dynamical decoupling. This indicates a way to extend the desirable robustness of consensus-inspired algorithms to even more fields of application.

Luca Mazzarella; Francesco Ticozzi; Alain Sarlette

2013-11-14

469

Stability of the replica symmetric solution in diluted perceptron learning  

NASA Astrophysics Data System (ADS)

We study the role played by dilution in the average behavior of a perceptron model with continuous coupling with the replica method. We analyze the stability of the replica symmetric solution as a function of the dilution field for the generalization and memorization problems. Thanks to a Gardner-like stability analysis we show that at any fixed ratio ? between the number of patterns M and the dimension N of the perceptron (? = M/N), there exists a critical dilution field hc above which the replica symmetric ansatz becomes unstable.

Lage-Castellanos, Alejandro; Pagnani, Andrea; Quintero Angulo, Gretel

2013-02-01

470

The structure of supersymmetry in ${\\cal PT}$ symmetric quantum mechanics  

E-print Network

The structure of supersymmetry is analyzed systematically in ${\\cal PT}$ symmetric quantum mechanical theories. We give a detailed description of supersymmetric systems associated with one dimensional ${\\cal PT}$ symmetric quantum mechanical theories. We show that there is a richer structure present in these theories compared to the conventional theories associated with Hermitian Hamiltonians. We bring out various properties associated with these supersymmetric systems and generalize such quantum mechanical theories to higher dimensions as well as to the case of one dimensional shape invariant potentials.

D. Bazeia; Ashok Das; L. Greenwood; L. Losano

2008-11-06

471

A new conformal duality of spherically symmetric space-times  

E-print Network

A contribution linear in r to the gravitational potential can be created by a suitable conformal duality transformation: the conformal factor is 1/(1+r)^2 and r will be replaced by r/(1+r), where r is the Schwarzschild radial coordinate. Thus, every spherically symmetric solution of conformal Weyl gravity is conformally related to an Einstein space. This result finally resolves a long controversy about this topic. As a byproduct, we present an example of a spherically symmetric Einstein space which is a limit of a sequence of Schwarzschild-de Sitter space-times but which fails to be expressable in Schwarzschild coordinates. This example also resolves a long controversy.

H. -J. Schmidt

1999-05-28

472

Parity-time symmetric Bragg structure in atomic vapor.  

PubMed

We propose an efficient scheme in helium or alkaline earth atomic vapor to achieve a parity-time symmetric Bragg structure using coherent lights. Unidirectional invisibility can be realized in this scheme, i.e., the atomic vapor shows total transparency for probe light incident from one particular direction, but exhibits enhanced Bragg reflection for probe from the opposite side. By changing the relative phase between the coherent lights, this direction can easily be manipulated, providing a convenient way for investigating special properties of -symmetric Bragg structures. PMID:25401544

Chen, Zhongjie; Wang, Haidong; Luo, Bin; Guo, Hong

2014-10-20

473

Adiabatic approximation in PT-symmetric quantum mechanics  

NASA Astrophysics Data System (ADS)

In this paper, we present a quantitative sufficient condition for adiabatic approximation in PT-symmetric quantum mechanics, which yields that a state of the PT-symmetric quantum system at any time will remain approximately in the m-th eigenstate up to a multiplicative phase factor whenever it is initially in the m-th eigenstate of the Hamiltonian. In addition, we estimate the approximation errors by the distance and the fidelity between the exact solution and the adiabatic approximate solution to the time evolution equation, respectively.

Guo, ZhiHua; Cao, HuaiXin; Lu, Ling

2014-10-01

474

Analog Electromagnetism in a Symmetrized $^3$He-A  

E-print Network

We derive a low temperature effective action for the order parameter in a symmetrized phase A of helium 3, where the Fermi velocity equals the transversal velocity of low energy fermionic quasiparticles. The effective action has a form of the electromagnetic action. This analog electromagnetism is a part of the program to derive analog gravity and the standard model as a low energy effective theory in a condensed matter system. For the analog gauge field to satisfy the Maxwell equations interactions in $^3$He require special tuning that leads to the symmetric case.

Jacek Dziarmaga

2001-12-18

475

Measurements and searches with top quarks  

SciTech Connect

In 1995 the last missing member of the known families of quarks, the top quark, was discovered by the CDF and D0 experiments at the Tevatron, a proton-antiproton collider at Fermilab near Chicago. Until today, the Tevatron is the only place where top quarks can be produced. The determination of top quark production and properties is crucial to understand the Standard Model of particle physics and beyond. The most striking property of the top quark is its mass--of the order of the mass of a gold atom and close to the electroweak scale--making the top quark not only interesting in itself but also as a window to new physics. Due to the high mass, much higher than of any other known fermion, it is expected that the top quark plays an important role in electroweak symmetry breaking, which is the most prominent candidate to explain the mass of particles. In the Standard Model, electroweak symmetry breaking is induced by one Higgs field, producing one additional physical particle, the Higgs boson. Although various searches have been performed, for example at the Large Electron Positron Collider (LEP), no evidence for the Higgs boson could yet be found in any experiment. At the Tevatron, multiple searches for the last missing particle of the Standard Model are ongoing with ever higher statistics and improved analysis techniques. The exclusion or verification of the Higgs boson can only be achieved by combining many techniques and many final states and production mechanisms. As part of this thesis, the search for Higgs bosons produced in association with a top quark pair (t{bar t}H) has been performed. This channel is especially interesting for the understanding of the coupling between Higgs and the top quark. Even though the Standard Model Higgs boson is an attractive candidate, there is no reason to believe that the electroweak symmetry breaking is induced by only one Higgs field. In many models more than one Higgs boson are expected to exist, opening even more channels to search for charged or neutral Higgs bosons. Depending on its mass, the charged Higgs boson is expected to decay either into top quarks or be the decay product of a top quark. For masses below the top quark mass, the top decay into a charged Higgs boson and a b quark can occur at a certain rate, additionally to the decays into W bosons and a b quark. The different decays of W and charged Higgs bosons can lead to deviations of the observed final number of events in certain final states with respect to the Standard Model expectation. A global search for charged Higgs bosons in top quark pair events is presented in this thesis, resulting in the most stringent limits to-date. Besides the decay of top quarks into charged Higgs or W bosons, new physics can also show up in the quark part of the decay. While in the Standard Model the top quark decays with a rate of about 100% into a W boson and a b quark, there are models where the top quark can decay into a W boson and a non-b quark. The ratio of branching fractions in which the top quark decays into a b quark over the branching fractions in which the top quark decays into all quarks is measured as part of this thesis, yielding the most precise measurement today. Furthermore, the Standard Model top quark pair production cross section is essential to be known precisely since the top quark pair production is the main background for t{bar t}H production and many other Higgs and beyond the Standard Model searches. However, not only the search or the test of the Standard Model itself make the precise measurement of the top quark pair production cross section interesting. As the cross section is calculated with high accuracy in perturbative QCD, a comparison of the measurement to the theory expectation yields the possibility to extract the top quark mass from the cross section measurement. Although many dedicated techniques exist to measure the top quark mass, the extraction from the cross section represents an important complementary measurement. The latter is briefly discussed in this thesis and compared to direct top ma

Peters, Reinhild Yvonne; /Wuppertal U.

2008-10-01

476

Exploring the anomalous Higgs-top couplings  

NASA Astrophysics Data System (ADS)

The top quark with its large Yukawa coupling is crucially important to explore TeV scale physics. Therefore, the study of the Higgs-top sector is highly motivated to look for any deviations from the standard model predictions. The most general lowest-order Lagrangian for the Higgs-top Yukawa coupling has scalar (?) and pseudoscalar (? ˜) components. Currently, these couplings are constrained indirectly using the present experimental limits on the Higgs-?-? and Higgs-gluon-gluon couplings. Furthermore, stronger bounds on ? and ? ˜ are obtained using the limits on the electric dipole moments (EDM). In this paper, we propose an asymmetrylike observable O? in tt ¯H production at the LHC to probe the Higgs-top coupling and to distinguish between the scalar and pseudoscalar components. We also show that the presence of the pseudoscalar component in the Higgs-top Yukawa coupling leads to a sizeable value for the top quark EDM. It is shown that a limit of 10-19 e.cm, which is achievable by the future e-e+ collider, allows us to exclude a significant region in the (? ,? ˜) plane.

Khatibi, Sara; Najafabadi, Mojtaba Mohammadi

2014-10-01

477

Experimental and theoretical studies of plasmon-molecule interactions.  

PubMed

Plasmon-molecule interactions are widely believed to involve photo-induced interferences between the localized excitation of individual electrons in molecules and the large collective excitation of conduction electrons in metal particles. The intrinsic multi-scale characteristics of plasmon-molecule interactions not only offer great opportunities for realizing precise top-down control of the optical properties of individual molecules, but also allow for accurate bottom-up manipulation of light polarization and propagation as a result of molecular excitation. However, the temporal and spatial complexity of plasmon-molecule experiments severely limits our interpretation and understanding of interactions that have important applications in dye-sensitized solar cells, single-molecule detectors, photoconductive molecular electronics, all-optical switching and photo-catalytic water splitting. This review aims to outline recent progress in experimental practice and theory for probing and exploiting the subtle coupling between discrete molecular orbitals and continuous metallic bands. For each experimental technique or theoretical model, the fundamental mechanisms and relevant applications are discussed in detail with specific examples. In addition, the experimental validation of theoretical models and the computational design of functional devices are both highlighted. Finally, a brief summary is presented together with an outlook for potential future directions of this emerging interdisciplinary research field. PMID:22935744

Chen, Hanning; Schatz, George C; Ratner, Mark A

2012-09-01

478

Single molecule laser spectroscopy.  

PubMed

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. PMID:25156641

Atta, Diaa; Okasha, Ali

2015-01-25

479

Heavy Hadron Molecules  

SciTech Connect

The open charm mesons D{sub s0}*(2317), D{sub s1}(2460) and the hidden charm meson X(3872) are discussed as hadron molecules. Using a phenomenological Lagrangian approach we consider the strong and radiative decays of the D{sub s0}*(2317) and D{sub s1}(2460) states. The X(3872) is assumed to consist dominantly of molecular hadronic components with an additional small admixture of a charmonium configuration. Observed radiative ({gamma}J/{psi} and {gamma}{psi}(2s)) and strong (J/{psi}2{pi} and J/{psi}3{pi}) decays are shown to be consistent with the molecular structure assumption of the X(3872).

Gutsche, Thomas; Lyubovitskij, Valery E. [Institut fuer Theoretische Physik, Universitaet Tuebingen, Kepler Center for Astro and Particle Physics, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)

2010-08-05

480

Charged charmonium molecules  

SciTech Connect

We make use of a self-consistent quark-model based study of four-quark charmonium-like states to interpret recent charmonium experimental data. We conclude that there exists a D*D* meson-meson molecule with quantum numbers (I{sup G})J{sup PC}=(1{sup -})2{sup ++}. Our study confirms the presence of charged charmonium-like resonances on the excited charmonium spectrum. We find support from recent experimental data by the Belle Collaboration [R. Mizuk et al. (Belle Collaboration), Phys. Rev. D 78, 072004 (2008)]. Confirmation of the experimental data by the Belle Collaboration and the determination of the quantum numbers of the new structures would help in discriminating among different theoretical models and would give further support to the theoretical analysis of T. Fernandez-Carames, A. Valcarce, and J. Vijande [Phys. Rev. Lett. 103, 222001 (2009)].

Carames, T. F.; Valcarce, A.; Vijande, J. [Departamento de Fisica Fundamental, Universidad de Salamanca, E-37008 Salamanca (Spain); Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Valencia (UV) and IFIC (UV-CSIC), Valencia (Spain)

2010-09-01

481

Molecules in the Spotlight  

SciTech Connect

SLAC has just unveiled the world's first X-ray laser, the LCLS. This machine produces pulses of X-rays that are ten billion times brighter than those from conventional sources. One of the goals of this machine is to make movies of chemical reactions, including reactions necessary for life and reactions that might power new energy technologies. This public lecture will show the first results from the LCLS. As a first target, we have chosen nitrogen gas, the main component of the air we breathe. Using the unprecedented power of the LCLS X-rays as a blasting torch, we have created new forms of this molecule and with unique electronic arrangements. Please share with us the first insights from this new technology.

Cryan, James

2010-01-26

482

5 CFR 1312.27 - Top secret control.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Top secret control. 1312.27 Section 1312...Classified Information § 1312.27 Top secret control. The EOP Security Officer serves as the Top Secret Control Officer (TSCO) for OMB....

2011-01-01

483

5 CFR 1312.27 - Top secret control.  

...2014-01-01 2014-01-01 false Top secret control. 1312.27 Section 1312...Classified Information § 1312.27 Top secret control. The EOP Security Officer serves as the Top Secret Control Officer (TSCO) for OMB....

2014-01-01

484

5 CFR 1312.27 - Top secret control.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Top secret control. 1312.27 Section 1312...Classified Information § 1312.27 Top secret control. The EOP Security Officer serves as the Top Secret Control Officer (TSCO) for OMB....

2013-01-01

485

5 CFR 1312.27 - Top secret control.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Top secret control. 1312.27 Section 1312...Classified Information § 1312.27 Top secret control. The EOP Security Officer serves as the Top Secret Control Officer (TSCO) for OMB....

2010-01-01

486

5 CFR 1312.27 - Top secret control.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Top secret control. 1312.27 Section 1312...Classified Information § 1312.27 Top secret control. The EOP Security Officer serves as the Top Secret Control Officer (TSCO) for OMB....

2012-01-01

487

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

488

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

489

Effects of High-Top and Low-Top Shoes on Ankle Inversion  

PubMed Central

Objective: To determine the differences in the rate and amount of ankle inversion in subjects wearing high-top and low-top shoes. Design and Setting: Subjects were filmed at 60 Hz while on an inversion platform that suddenly inverted the right ankle 35°. We measured 5 tr