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1

Anderson Localization in Atoms  

E-print Network

A statistical analysis of the ionization yield of one-dimensional, periodically driven hydrogen Rydberg states is provided. We find excellent agreement with predictions for the conductance across an Anderson-localized, quasi one-dimensional, disordered wire, in the semiclassical limit of highly excited atomic initial states.

Sandro Wimberger; Andreas Buchleitner

2002-11-12

2

Anderson Localization of Solitons  

SciTech Connect

At low temperature, a quasi-one-dimensional ensemble of atoms with an attractive interaction forms a bright soliton. When exposed to a weak and smooth external potential, the shape of the soliton is hardly modified, but its center-of-mass motion is affected. We show that in a spatially correlated disordered potential, the quantum motion of a bright soliton displays Anderson localization. The localization length can be much larger than the soliton size and could be observed experimentally.

Sacha, Krzysztof; Zakrzewski, Jakub [Instytut Fizyki imienia Mariana Smoluchowskiego and Mark Kac Complex Systems Research Center, Uniwersytet Jagiellonski, ulica Reymonta 4, PL-30-059 Krakow (Poland); Laboratoire Kastler-Brossel, UPMC, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France); Mueller, Cord A. [Laboratoire Kastler-Brossel, UPMC, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France); Physikalisches Institut, Universitaet Bayreuth, D-95440 Bayreuth (Germany); Delande, Dominique [Laboratoire Kastler-Brossel, UPMC, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France)

2009-11-20

3

Anderson localization in QCD-like theories  

NASA Astrophysics Data System (ADS)

We review the present status of the Anderson transition in the spectrum of the Dirac operator of QCD-like theories on the lattice. Localized modes at the low end of the spectrum have been found in SU(2) Yang-Mills theory with overlap and staggered valence fermions as well as in Nf = 2+1 QCD with staggered quarks. We draw an analogy between the transition from localized to delocalized modes in the Dirac spectrum and the Anderson transition in electronic systems. The QCD transition turns out to be in the same universality class as the transition in the corresponding Anderson model. We also speculate on the possible physical relevance of this transition to QCD at high temperature and the possible finite temperature phase transition in QCD-like models with different fermion contents.

Giordano, Matteo; Kovács, Tamás G.; Pittler, Ferenc

2014-10-01

4

Electronic control of optical Anderson localization modes.  

PubMed

Anderson localization of light has been demonstrated in a few different dielectric materials and lithographically fabricated structures. However, such localization is difficult to control, and requires strong magnetic fields or nonlinear optical effects, and electronic control has not been demonstrated. Here, we show control of optical Anderson localization using charge carriers injected into more than 100 submicrometre-scale p-n diodes. The diodes are embedded into the cross-section of the optical waveguide and are fabricated with a technology compatible with the current electronics industry. Large variations in the output signal, exceeding a factor of 100, were measured with 1 V and a control current of 1 mA. The transverse footprint of our device is only 0.125 µm(2), about five orders of magnitude smaller than optical two-dimensional lattices. Whereas all-electronic localization has a narrow usable bandwidth, electronically controlled optical localization can access more than a gigahertz of bandwidth and creates new possibilities for controlling localization at radiofrequencies, which can benefit applications such as random lasers, optical limiters, imagers, quantum optics and measurement devices. PMID:24681777

Mookherjea, Shayan; Ong, Jun Rong; Luo, Xianshu; Guo-Qiang, Lo

2014-05-01

5

Towards a New Proof of Anderson Localization  

E-print Network

The wave function of a non-relativistic particle in a periodic potential admits oscillatory solutions, the Bloch waves. In the presence of a random noise contribution to the potential the wave function is localized. We outline a new proof of this Anderson localization phenomenon in one spatial dimension, extending the classical result to the case of a periodic background potential. The proof makes use of techniques previously developed to study the effects of noise on reheating in inflationary cosmology, employing methods of random matrix theory.

Brandenberger, Robert

2008-01-01

6

Towards a New Proof of Anderson Localization  

E-print Network

The wave function of a non-relativistic particle in a periodic potential admits oscillatory solutions, the Bloch waves. In the presence of a random noise contribution to the potential the wave function is localized. We outline a new proof of this Anderson localization phenomenon in one spatial dimension, extending the classical result to the case of a periodic background potential. The proof makes use of techniques previously developed to study the effects of noise on reheating in inflationary cosmology, employing methods of random matrix theory.

Robert Brandenberger; Walter Craig

2008-05-27

7

Dynamical Localization for Unitary Anderson Models  

E-print Network

This paper establishes dynamical localization properties of certain families of unitary random operators on the d-dimensional lattice in various regimes. These operators are generalizations of one-dimensional physical models of quantum transport and draw their name from the analogy with the discrete Anderson model of solid state physics. They consist in a product of a deterministic unitary operator and a random unitary operator. The deterministic operator has a band structure, is absolutely continuous and plays the role of the discrete Laplacian. The random operator is diagonal with elements given by i.i.d. random phases distributed according to some absolutely continuous measure and plays the role of the random potential. In dimension one, these operators belong to the family of CMV-matrices in the theory of orthogonal polynomials on the unit circle. We implement the method of Aizenman-Molchanov to prove exponential decay of the fractional moments of the Green function for the unitary Anderson model in the following three regimes: In any dimension, throughout the spectrum at large disorder and near the band edges at arbitrary disorder and, in dimension one, throughout the spectrum at arbitrary disorder. We also prove that exponential decay of fractional moments of the Green function implies dynamical localization, which in turn implies spectral localization. These results complete the analogy with the self-adjoint case where dynamical localization is known to be true in the same three regimes.

Eman Hamza; Alain Joye; Günter Stolz

2009-02-28

8

Microwave-Driven Atoms: From Anderson Localization to Einstein's Photoeffect  

E-print Network

We study the counterpart of Anderson localization in driven one-electron Rydberg atoms. By changing the initial Rydberg state at fixed microwave frequency and interaction time, we numerically monitor the crossover from Anderson localization to the photo effect in the atomic ionization signal.

Alexej Schelle; Dominique Delande; Andreas Buchleitner

2009-05-04

9

Observing transverse Anderson localization in random air line based fiber  

NASA Astrophysics Data System (ADS)

The concept of Anderson localization has been applied to electromagnetic waves for decades and strong photon localization effect has been observed in many two-dimensional systems including optical lattice and optical fibers. Among different types of optical fibers, both fibers with and without air hole were investigated. Air hole based fiber has significant higher refractive index contrast than other fibers which allow much lower filling fraction in order to observe Anderson localization. In a previous research, Anderson localization was observed near the fiber edge with an air fillfraction of 5.5%. At the fiber center region with only 2.2% air fill-fraction, Anderson localization disappeared. However, we observed Anderson localization in fibers with much lower air fill-fraction. In our experiments, random air line fibers with 150, 250 and 350 ?m diameters were fabricated and characterized by scanning electronic microscopy (SEM). Averaged air line diameters were 177, 247 and 387 nm for the 150, 250 and 350 ?m diameter fibers, respectively. Air fill-fraction was also measured at fiber center, middle and edge regions. Beam profiles were imaged into a charge couple device (CCD) and Anderson localization was observed. Unlike the previous research in which Anderson localization was only observed at the fiber edge due to non-uniform air line distribution, we observed Anderson localization within the fiber area with air fill-fraction significantly lower than the previous investigation. This is because with smaller air line diameter our fiber has higher air lines density than the previous report.

Chen, Minghan; Li, Ming-Jun

2014-02-01

10

Strong Anderson localization in cold atom quantum quenches.  

PubMed

Signatures of Anderson localization in the momentum distribution of a cold atom cloud after a quantum quench are studied. We consider a quasi-one-dimensional cloud initially prepared in a well-defined momentum state, and expanding for some time in a disorder speckle potential. Quantum interference generates a peak in the forward scattering amplitude which, unlike the common weak localization backscattering peak, is a signature of strong Anderson localization. We present a nonperturbative, and fully time resolved description of the phenomenon, covering the entire diffusion-to-localization crossover. Our results should be observable by present day experiments. PMID:24702342

Micklitz, T; Müller, C A; Altland, A

2014-03-21

11

Periodic-Orbit Theory of Anderson Localization on Graphs  

E-print Network

We present the first quantum system where Anderson localization is completely described within periodic-orbit theory. The model is a quantum graph analogous to an a-periodic Kronig-Penney model in one dimension. The exact expression for the probability to return of an initially localized state is computed in terms of classical trajectories. It saturates to a finite value due to localization, while the diagonal approximation decays diffusively. Our theory is based on the identification of families of isometric orbits. The coherent periodic-orbit sums within these families, and the summation over all families are performed analytically using advanced combinatorial methods.

Holger Schanz; Uzy Smilansky

1999-12-15

12

Defect-controlled Anderson localization of light in photonic lattices  

NASA Astrophysics Data System (ADS)

The transverse localization of light in a disordered photonic lattice with a central defect is analyzed numerically. The effect of different input beam widths on various regimes of Anderson localization is investigated. The inclusion of a defect enhances the localization of both narrow and broad beams, as compared to the lattice with no defect. But, in the case of a broad beam a higher disorder level is needed to reach the same localization as for a narrow input beam. It is also investigated how the transverse localization of light in such geometries depends on both the strength of disorder and the strength of nonlinearity in the system. While in the linear regime the localization is most pronounced in the lattice with the defect, in the nonlinear regime this is not the case.

Jovi?, Dragana

2013-11-01

13

Zero-mean circular Bessel statistics and Anderson localization  

NASA Astrophysics Data System (ADS)

We demonstrate that a circular Bessel density function describes the electromagnetic field statistics in the Anderson localization regime using example numerical terahertz field data in strongly scattering media. This density function for localized fields provides a measure that allows identification and description in a manner akin to the Gaussian density function for weakly interacting scatterers, the mathematical framework to date for statistical optics. Our theory provides a framework for improved understanding of wave propagation in random media, random scattering media characterization, and imaging in and through randomly scattering media.

Newman, Jason A.; Chen, Yulu; Webb, Kevin J.

2014-08-01

14

Zero-mean circular Bessel statistics and Anderson localization.  

PubMed

We demonstrate that a circular Bessel density function describes the electromagnetic field statistics in the Anderson localization regime using example numerical terahertz field data in strongly scattering media. This density function for localized fields provides a measure that allows identification and description in a manner akin to the Gaussian density function for weakly interacting scatterers, the mathematical framework to date for statistical optics. Our theory provides a framework for improved understanding of wave propagation in random media, random scattering media characterization, and imaging in and through randomly scattering media. PMID:25215701

Newman, Jason A; Chen, Yulu; Webb, Kevin J

2014-08-01

15

Anderson Localization: Dynamical Cluster Approximation - Typical Medium Theory Perspective  

NASA Astrophysics Data System (ADS)

Mean field theories like the coherent potential approximation (CPA) and its cluster extensions, including the dynamical cluster approximation (DCA), fail to describe the Anderson localization transition in disordered systems. This failure is intrinsic to these theories as the algebraically averaged quantities used in them always favor the metallic state, and hence cannot describe the localization transition. Here we extend the Typical Medium Theory (TMT), which replaces the average quantities with their corresponding typical (geometrically averaged) equivalents, to its cluster form such that non-local correlations can be incorporated systematically. We apply our method to study the localization phenomena in various dimensions. Such an approach opens a new avenue to study localization effect both in model and in real materials.

Ekuma, Chinedu; Meng, Ziyang; Terletska, Hanna; Moreno, Juana; Jarrell, Mark; Dobrosavljevic, Vladimir

2013-03-01

16

Anderson localization of electromagnetic waves in confined dielectric media Marian Rusek1,2  

E-print Network

, the multiple scattering and interference are well known phenom- ena for electromagnetic waves and, consequentlyAnderson localization of electromagnetic waves in confined dielectric media Marian Rusek1, Poland Received 21 August 1998 Anderson localization of electromagnetic waves in random arrays

Rusek, Marian

17

Destruction of Anderson localization by nonlinearity in kicked rotator at different effective dimensions  

NASA Astrophysics Data System (ADS)

We study numerically the frequency modulated kicked nonlinear rotator with effective dimension d=1,2,3,4. We follow the time evolution of the model up to 109 kicks and determine the exponent ? of subdiffusive spreading which changes from 0.35 to 0.5 when the dimension changes from d = 1 to 4. All results are obtained in a regime of relatively strong Anderson localization well below the Anderson transition point existing for d = 3, 4. We explain that this variation of the exponent is different from the usual d- dimensional Anderson models with local nonlinearity where ? drops with increasing d. We also argue that the renormalization arguments proposed by Cherroret N et al (arXiv:1401.1038) are not valid for this model and the Anderson model with local nonlinearity in d = 3.

Ermann, L.; Shepelyansky, D. L.

2014-08-01

18

Beyond Anderson Localization in 1D: Anomalous Localization of Microwaves in Random Waveguides.  

PubMed

Experimental evidence demonstrating that anomalous localization of waves can be induced in a controllable manner is reported. A microwave waveguide with dielectric slabs randomly placed is used to confirm the presence of anomalous localization. If the random spacing between slabs follows a distribution with a power-law tail (Lévy-type distribution), unconventional properties in the microwave-transmission fluctuations take place revealing the presence of anomalous localization. We study both theoretically and experimentally the complete distribution of the transmission through random waveguides characterized by ?=1/2 ("Lévy waveguides") and ?=3/4, ? being the exponent of the power-law tail of the Lévy-type distribution. As we show, the transmission distributions are determined by only two parameters, both of them experimentally accessible. Effects of anomalous localization on the transmission are compared with those from the standard Anderson localization. PMID:25526129

Fernández-Marín, A A; Méndez-Bermúdez, J A; Carbonell, J; Cervera, F; Sánchez-Dehesa, J; Gopar, V A

2014-12-01

19

Beyond Anderson Localization in 1D: Anomalous Localization of Microwaves in Random Waveguides  

NASA Astrophysics Data System (ADS)

Experimental evidence demonstrating that anomalous localization of waves can be induced in a controllable manner is reported. A microwave waveguide with dielectric slabs randomly placed is used to confirm the presence of anomalous localization. If the random spacing between slabs follows a distribution with a power-law tail (Lévy-type distribution), unconventional properties in the microwave-transmission fluctuations take place revealing the presence of anomalous localization. We study both theoretically and experimentally the complete distribution of the transmission through random waveguides characterized by ? =1 /2 ("Lévy waveguides") and ? =3 /4 , ? being the exponent of the power-law tail of the Lévy-type distribution. As we show, the transmission distributions are determined by only two parameters, both of them experimentally accessible. Effects of anomalous localization on the transmission are compared with those from the standard Anderson localization.

Fernández-Marín, A. A.; Méndez-Bermúdez, J. A.; Carbonell, J.; Cervera, F.; Sánchez-Dehesa, J.; Gopar, V. A.

2014-12-01

20

Observation of migrating transverse Anderson localizations of light in nonlocal media.  

PubMed

We report the experimental observation of the interaction and attraction of many localized modes in a two-dimensional system realized by a disordered optical fiber supporting transverse Anderson localization. We show that a nonlocal optically nonlinear response of thermal origin alters the localization length by an amount determined by the optical power and also induces an action at a distance between the localized modes and their spatial migration. Evidence of a collective and strongly interacting regime is given. PMID:24877941

Leonetti, Marco; Karbasi, Salman; Mafi, Arash; Conti, Claudio

2014-05-16

21

Matter wave transport and Anderson localization in anisotropic three-dimensional disorder  

E-print Network

epl draft Matter wave transport and Anderson localization in anisotropic three-dimensional disorder study quantum transport of matter waves in anisotropic three-dimensional dis- order. First, we show is directly relevant to ultracold-matter waves in optical disorder, and implications on recent experiments

Paris-Sud XI, Université de

22

Numerical study of light correlations in a random medium close to the Anderson localization threshold.  

PubMed

We applied a finite-difference time domain algorithm to the study of field and intensity correlations in random media. Close to the onset of Anderson localization, we observe deviations of the correlation functions, in both shape and magnitude, from those predicted by the diffusion theory. Physical implications of the observed phenomena are discussed. PMID:15143626

Chang, Shih-Hui; Taflove, Allen; Yamilov, Alexey; Burin, Aleksander; Cao, Hui

2004-05-01

23

Direct observation of Anderson localization of matter-waves in an optical disorder  

NASA Astrophysics Data System (ADS)

In 1958, P.W. Anderson predicted the localization^1 of electronic wave functions in disordered crystals, and the resulting absence of diffusion. It has been realized later that Anderson Localization is ubiquitous in wave physics^2, and this has prompted an intense activity to observe it with light, microwaves, sound waves, and electron gases, but to our knowledge there was no direct observation of exponential spatial localization of matter-waves (electrons or others). We have observed directly^3 exponential localization of the wave function of ultracold atoms released into a one-dimensional waveguide in the presence of a controlled disorder created by laser speckle. We will present this work, and the prospects of extending that experimental scheme to quantum gases in higher dimensions (2D and 3D), and with controlled interactions. We will also discuss its significance in the rapidly growing field of quantum simulators. 1 Anderson, P.W. Absence of diffusion in certain random lattices. Phys. Rev. 109, 1492-1505 (1958). 2 Van Tiggelen, B. Anderson localization of waves. In Wave diffusion in complex media 1998, edited by J.P. Fouque, Les Houches Lectures (Kluwer, Dordrecht, 1999). 3 Juliette Billy, Vincent Josse, Zhanchun Zuo, Alain Bernard, Ben Hambrecht, Pierre Lugan, David Cl'ement, Laurent Sanchez-Palencia, Philippe Bouyer^ & Alain Aspect. Direct observation of Anderson localization of matter-waves in a controlled disorder Nature, 453, 891 (2008). Work published back to back with a related work in the Inguscio's group in Florence: G. Roati et al., Nature, 453, 895 (2008).

Aspect, Alain

2009-03-01

24

Marginal Anderson localization and many-body delocalization  

NASA Astrophysics Data System (ADS)

We consider d -dimensional systems which are localized in the absence of interactions, but whose single-particle localization length diverges near a discrete set of (single-particle) energies, with critical exponent ? . This class includes disordered systems with intrinsic or symmetry protected topological bands, such as disordered integer quantum Hall insulators. We show that such marginally localized systems exhibit anomalous properties intermediate between localized and extended, including vanishing dc conductivity but subdiffusive dynamics, and fractal entanglement (an entanglement entropy with a scaling intermediate between area and volume law). We investigate the stability of marginal localization in the presence of interactions, and argue that arbitrarily weak short-range interactions trigger delocalization for partially filled bands at nonzero energy density if ? ?1 /d . We use the Harris-Chayes bound ? ?2 /d to conclude that marginal localization is generically unstable in the presence of interactions. Our results suggest the impossibility of stabilizing quantized Hall conductance at nonzero energy density.

Nandkishore, Rahul; Potter, Andrew C.

2014-11-01

25

Anderson localization through Polyakov loops: Lattice evidence and random matrix model  

NASA Astrophysics Data System (ADS)

We investigate low-lying fermion modes in SU(2) gauge theory at temperatures above the phase transition. Both staggered and overlap spectra reveal transitions from chaotic (random matrix) to integrable (Poissonian) behavior accompanied by an increasing localization of the eigenmodes. We show that the latter are trapped by local Polyakov loop fluctuations. Islands of such “wrong” Polyakov loops can therefore be viewed as defects leading to Anderson localization in gauge theories. We find strong similarities in the spatial profile of these localized staggered and overlap eigenmodes. We discuss possible interpretations of this finding and present a sparse random matrix model that reproduces these features.

Bruckmann, Falk; Kovács, Tamás G.; Schierenberg, Sebastian

2011-08-01

26

Abnormal anti-Stokes Raman scattering and coherent backscattering as manifestation of Anderson localization of light in nonlinear mesoscopic materials  

NASA Astrophysics Data System (ADS)

We demonstrate that under continuous single-beam excitation, one can generate an abnormal anti-Stokes Raman emission (AASRE) whose properties are similar to a coherent anti-Stokes Raman scattering. The effect has been observed in mesoscopic materials, which possess intrinsically nonlinear properties [lithium niobate (LiNbO3), bismuth germanium oxide (Bi12GeO20; BGO), bismuth silicon oxide (Bi12GeO20; BSO)], which have a nonzero electric susceptibility of the third order, ?(3)?0. Corroborated Raman and coherent backscattering studies demonstrate that the occurrence of both effects is conditioned by the existence of a mesoscopic morphology of the sample, which is able to ensure efficient transport of the light inside the sample through a multiple light scattering mechanism. In this context, both AASRE and coherent backscattering effects are because of the Anderson localization of the light.

Smaranda, Ion; Mihut, Lucian; Baibarac, Mihaela; Baltog, Ioan; Lefrant, Serge

2014-09-01

27

Local Polarization Distribution and Edwards-Anderson Order Parameter of Relaxor Ferroelectrics  

Microsoft Academic Search

The temperature dependence of the Edwards-Anderson order parameter qEA and the local polarization distribution function W\\\\(p-->\\\\) have been determined in a PMN single crystal via 2D 93Nb NMR. A glasslike freezing of reorientable polar clusters occurs in the temperature range of the diffuse relaxor transition, whereas the NMR spectra corresponding to pinned nanodomains do not change with temperature. The obtained

R. Blinc; J. Dolins Ek; A. Gregorovic; B. Zalar; C. Filipic; Z. Kutnjak; A. Levstik; R. Pirc

1999-01-01

28

Conductance fluctuation of edge-disordered graphene nanoribbons: Crossover from diffusive transport to Anderson localization  

SciTech Connect

Conductance fluctuation of edge-disordered graphene nanoribbons (ED-GNRs) is examined using the non-equilibrium Green's function technique combined with the extended Hückel approximation. The mean free path ? and the localization length ? of the ED-GNRs are determined to classify the quantum transport regimes. In the diffusive regime where the length L{sub c} of the ED-GNRs is much longer than ? and much shorter than ?, the conductance histogram is given by a Gaussian distribution function with universal conductance fluctuation. In the localization regime where L{sub c}??, the histogram is no longer the universal Gaussian distribution but a lognormal distribution that characterizes Anderson localization.

Takashima, Kengo [Department of Electrical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585 (Japan); Yamamoto, Takahiro, E-mail: takahiro@rs.tus.ac.jp [Department of Electrical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585 (Japan); Department of Liberal Arts (Physics), Tokyo University of Science, 6-3-1 Niijuku, Katsushika, Tokyo 125-8585 (Japan)

2014-03-03

29

Anderson localization and Brewster anomalies in photonic disordered quasiperiodic lattices  

SciTech Connect

A comprehensive study of the properties of light propagation through one-dimensional photonic disordered quasiperiodic superlattices, composed of alternating layers with random thicknesses of air and a dispersive metamaterial, is theoretically performed. The superlattices consist of the successive stacking of N quasiperiodic Fibonacci or Thue-Morse heterostructures. The width of the slabs in the photonic superlattice may randomly fluctuate around its mean value, which introduces a structural disorder into the system. It is assumed that the left-handed layers have a Drude-type dispersive response for both the dielectric permittivity and magnetic permeability, and Maxwell's equations are solved for oblique incidence by using the transfer-matrix formalism. The influence of both quasiperiodicity and structural disorder on the localization length and Brewster anomalies are thoroughly discussed.

Reyes-Gomez, E. [Instituto de Fisica, Universidad de Antioquia, AA 1226, Medellin (Colombia); Bruno-Alfonso, A. [Faculdade de Ciencias, UNESP-Universidade Estadual Paulista, 17033-360 Bauru-SP (Brazil); Cavalcanti, S. B. [Instituto de Fisica, Universidade Federal de Alagoas, 57072-970 Maceio-AL (Brazil); Oliveira, L. E. [Instituto de Fisica, Universidade Estadual de Campinas-UNICAMP, 13083-859 Campinas-SP (Brazil)

2011-09-15

30

Anderson localization and Brewster anomalies in photonic disordered quasiperiodic lattices.  

PubMed

A comprehensive study of the properties of light propagation through one-dimensional photonic disordered quasiperiodic superlattices, composed of alternating layers with random thicknesses of air and a dispersive metamaterial, is theoretically performed. The superlattices consist of the successive stacking of N quasiperiodic Fibonacci or Thue-Morse heterostructures. The width of the slabs in the photonic superlattice may randomly fluctuate around its mean value, which introduces a structural disorder into the system. It is assumed that the left-handed layers have a Drude-type dispersive response for both the dielectric permittivity and magnetic permeability, and Maxwell's equations are solved for oblique incidence by using the transfer-matrix formalism. The influence of both quasiperiodicity and structural disorder on the localization length and Brewster anomalies are thoroughly discussed. PMID:22060519

Reyes-Gómez, E; Bruno-Alfonso, A; Cavalcanti, S B; Oliveira, L E

2011-09-01

31

Evolution of locally excited avalanches in semiconductors  

E-print Network

We show that semiconductor avalanche photodiodes can exhibit diminutive amplification noise during the early evolution of avalanches. The noise is so low that the number of locally excited charges that seed each avalanche can be resolved. These findings constitute an important first step towards realization of a solid-state noiseless amplifier. Moreover, we believe that the experimental setup used, \\textit{i.e.}, time-resolving locally excited avalanches, will become a useful tool for optimizing the number resolution.

Z. L. Yuan; J. F. Dynes; A. W. Sharpe; A. J. Shields

2010-03-03

32

Transmission Eigenvalues and the Bare Conductance in the Crossover to Anderson Localization  

NASA Astrophysics Data System (ADS)

We measure the field transmission matrix t for microwave radiation propagating through random waveguides in the crossover to Anderson localization. From these measurements, we determine the dimensionless conductance g and the individual eigenvalues ?n of the transmission matrix tt† whose sum equals g. In diffusive samples, the highest eigenvalue, ?1, is close to unity corresponding to a transmission of nearly 100%, while for localized waves, the average of ?1, is nearly equal to g. We find that the spacing between average values of ln??n is constant and demonstrate that when surface interactions are taken into account it is equal to the inverse of the bare conductance.

Shi, Zhou; Genack, Azriel Z.

2012-01-01

33

Variational Monte Carlo Study of Anderson Localization in the Hubbard Model  

NASA Astrophysics Data System (ADS)

We have studied the effects of interactions on persistent currents in half-filled and quarter-filled Hubbard models with weak and intermediate strength disorder. Calculations are performed using a variational Gutzwiller ansatz that describes short range correlations near the Mott transition. A persistent current is induced with an Aharonov-Bohm flux, and the Anderson localization length is extracted from the scaling of the current with system size. We find that, at half filling, the localization length grows monotonically with interaction strength, even though the current itself is suppressed by strong correlations. This supports earlier dynamical mean field theory predictions that the elastic scattering rate is reduced near the Mott transition.

Atkinson, William; Farhoodfar, Avid; Gooding, Robert J.

2012-02-01

34

Numerical study of Anderson localization of terahertz waves in disordered waveguides  

E-print Network

We present a numerical study of electromagnetic wave transport in disordered quasi-one-dimensional waveguides at terahertz frequencies. Finite element method calculations of terahertz wave propagation within LiNbO$_{3}$ waveguides with randomly arranged air-filled circular scatterers exhibit an onset of Anderson localization at experimentally accessible length scales. Results for the average transmission as a function of waveguide length and scatterer density demonstrate a clear crossover from diffusive to localized transport regime. In addition, we find that transmission fluctuations grow dramatically when crossing into the localized regime. Our numerical results are in good quantitative agreement with theory over a wide range of experimentally accessible parameters both in the diffusive and localized regime opening the path towards experimental observation of terahertz wave localization.

Lapointe, C P; Enderli, F; Feurer, T; Skipetrov, S E; Scheffold, F

2014-01-01

35

Self-Consistent Theory of Anderson Localization in Two Dimensions in View of Exact Transport Equation  

NASA Astrophysics Data System (ADS)

Self-consistent theory of Anderson localization of two-dimensional non-interacting electrons is formulated in the context of the exact transport equation and conductivity expression derived by the present authors (YI). The irreducible scattering vertex by Vollhardt and Wölfle (VW) is used in this equation, determining the diffusion coefficient in the scattering vertex self-consistently, through Einstein relation. It predicts a similar localization length to that obtained by VW, but shows that the conductivity evaluated by the Kubo formula decays exponentially, as the system size approaches the localization length. The result is opposed to the prediction by VW, who showed different behaviour of the diffusion coefficient that is equivalent to our conductivity. Our calculation also implies that the localization may be described along with the Landau-Silin theory of Fermi liquid.

Yamane, Y.; Itoh, M.

2012-10-01

36

Pure point spectrum under 1-parameter perturbations and instability of Anderson localization  

NASA Astrophysics Data System (ADS)

We consider a selfadjoint operator, A, and a selfadjoint rank-one projection, P, onto a vector, ?, which is cyclic for A. We study the set of all eigenvalues of the operator A t = A+tP (t??) that belong to its essential spectrum (which does not depend on the parameter t). We prove that this set is empty for a dense set of values of t. Then we apply this result or its idea to questions of Anderson localization for 1-dimensional Schrödinger operators (discrete and continuous).

Gordon, A. Ya.

1994-08-01

37

High-Performance Local Area Communication With Fast Steven H. Rodrigues Thomas E. Anderson David E. Culler  

E-print Network

1993], Myrinet [Seitz 1994], and switched high- speed Ethernet has the potential to dramatically imHigh-Performance Local Area Communication With Fast Sockets Steven H. Rodrigues Thomas E. Anderson with large packets; most network traffic is small. We have devel- oped Fast Sockets, a local

Culler, David E.

38

Statistical measurements of quantum emitters coupled to Anderson-localized modes in disordered photonic-crystal waveguides  

E-print Network

Optical nanostructures have proven to be meritorious for tailoring the emission properties of quantum emitters. However, unavoidable fabrication imperfections may represent a nuisance. Quite remarkably, disorder offers new opportunities since light can be efficiently confined by random multiple scattering leading to Anderson localization. Here we investigate the effect of such disorder-induced cavities on the emission dynamics of single quantum dots embedded in disordered photonic-crystal waveguides. We present time-resolved measurements of both the total emission from Anderson-localized cavities and from single emitters that are coupled to the cavities. We observe both strongly inhibited and enhanced decay rates relative to the rate of spontaneous emission in a homogeneous medium. From a statistical analysis, we report an average Purcell factor of 2 in without any control on the quantum dot - cavity detuning. By spectrally tuning individual quantum dots into resonance with Anderson-localized modes, a maximum...

Javadi, Alisa; Sapienza, Luca; Thyrrestrup, Henri; Lodahl, Peter

2013-01-01

39

Light propagation and Anderson localization in superlattices containing metamaterials: effects of correlated disorder  

NASA Astrophysics Data System (ADS)

We discuss the effect of correlated disorder on light propagation and Anderson localization in a one-dimensional superlattice made up of air (A) and a dispersive metamaterial (M). Disorder is incorporated by assuming the layer widths to be random variables; however, here we consider the cases of correlated (i.e., the A and M layers with the same width) and completely anti-correlated (the total width of the A and M layers is fixed). We use transfer matrix techniques to obtain the localization length, and compare with the uncorrelated case. We have found that the photonic gaps of the corresponding periodic structure are not completely destroyed in the presence of disorder, giving rise to minima in the localization length. Near a gap, the behavior the localization length depends crucially on the physical origin of the gap (Bragg or non-Bragg gaps). We have found that the asymptotic behavior for the localization length ?6? for disordered metamaterials is not affected by correlations, and the Brewster anomalies, at which light is delocalized, are also present.

Rocha Dos Santos, Raimundo; Mogilevtsev, Dmitri; Pinheiro, Felipe; Cavalcanti, Solange; Oliveira, Luiz

2011-03-01

40

Nonuniversal Intensity Correlations in a Two-Dimensional Anderson-Localizing Random Medium  

NASA Astrophysics Data System (ADS)

Complex dielectric media often appear opaque because light traveling through them is scattered multiple times. Although the light scattering is a random process, different paths through the medium can be correlated encoding information about the medium. Here, we present spectroscopic measurements of nonuniversal intensity correlations that emerge when embedding quantum emitters inside a disordered photonic crystal that is found to Anderson-localize light. The emitters probe in situ the microscopic details of the medium, and imprint such near-field properties onto the far-field correlations. Our findings provide new ways of enhancing light-matter interaction for quantum electrodynamics and energy harvesting, and may find applications in subwavelength diffuse-wave spectroscopy for biophotonics.

García, Pedro David; Stobbe, Søren; Söllner, Immo; Lodahl, Peter

2012-12-01

41

One-dimensional Anderson Localization: distribution of wavefunction amplitude and phase at the band center  

NASA Astrophysics Data System (ADS)

The statistics of normalized wavefunctions in the one-dimensional (1d) Anderson model of localization is considered. It is shown that at any energy that corresponds to a rational filling factor f = p/q there is a statistical anomaly which is seen in expansion of the generating function (GF) to the order q-2 in the disorder parameter. We study in detail the principle anomaly at f = 1/2 that appears in the leading order. The transfer-matrix equation of the Fokker-Planck type with a two-dimensional internal space is derived for GF. It is shown that the zero-mode variant of this equation is integrable and a solution for the generating function is found in the thermodynamic limit.

Kravtsov, V. E.; Yudson, V. I.

2009-05-01

42

Statistics of the two-point transmission at Anderson localization transitions  

NASA Astrophysics Data System (ADS)

At Anderson critical points, the statistics of the two-point transmission TL for disordered samples of linear size L is expected to be multifractal with the following properties [Janssen , Phys. Rev. B 59, 15836 (1999)]: (i) the probability to have TL˜1/L? behaves as L?(?) , where the multifractal spectrum ?(?) terminates at ?=0 as a consequence of the physical bound TL?1 ; (ii) the exponents X(q) that govern the moments TLq¯˜1/LX(q) become frozen above some threshold: X(q?qsat)=-?(?=0) , i.e., all moments of order q?qsat are governed by the measure of the rare samples having a finite transmission (?=0) . In the present paper, we test numerically these predictions for the ensemble of L×L power-law random-banded matrices, where the random hopping Hi,j decays as a power law (b/|i-j|)a . This model is known to present an Anderson transition at a=1 between localized (a>1) and extended (a<1) states with critical properties that depend continuously on the parameter b . Our numerical results for the multifractal spectra ?b(?) for various b are in agreement with the relation ?(??0)=2[f(?=d+(?)/(2))-d] in terms of the singularity spectrum f(?) of individual critical eigenfunctions, in particular the typical exponents are related via the relation ?typ(b)=2[?typ(b)-d] . We also discuss the statistics of the two-point transmission in the delocalized phase and in the localized phase.

Monthus, Cécile; Garel, Thomas

2009-05-01

43

Statistical measurements of quantum emitters coupled to Anderson-localized modes in disordered photonic-crystal waveguides  

E-print Network

Optical nanostructures have proven to be meritorious for tailoring the emission properties of quantum emitters. However, unavoidable fabrication imperfections may represent a nuisance. Quite remarkably, disorder offers new opportunities since light can be efficiently confined by random multiple scattering leading to Anderson localization. Here we investigate the effect of such disorder-induced cavities on the emission dynamics of single quantum dots embedded in disordered photonic-crystal waveguides. We present time-resolved measurements of both the total emission from Anderson-localized cavities and from single emitters that are coupled to the cavities. We observe both strongly inhibited and enhanced decay rates relative to the rate of spontaneous emission in a homogeneous medium. From a statistical analysis, we report an average Purcell factor of 2 in without any control on the quantum dot - cavity detuning. By spectrally tuning individual quantum dots into resonance with Anderson-localized modes, a maximum Purcell factor of 23.8 is recorded, which lies at the onset of the strong coupling regime. The presented data quantify the potential of naturally occurring Anderson-localized cavities for controlling and enhancing the light-matter interaction strength, which is of relevance not only for cavity quantum-electrodynamics experiments but potentially also for efficient energy harvesting and controllable random lasing.

Alisa Javadi; Pedro D. Garcia; Luca Sapienza; Henri Thyrrestrup; Peter Lodahl

2013-01-02

44

Measurement of the Probability Distribution of Optical Transmittance on the Crossover to Anderson localization  

NASA Astrophysics Data System (ADS)

We report measurements of spectra of the field transmission matrix t for microwave radiation propagating through waveguide filled with randomly positioned dielectric scattering spheres in the Anderson localization transition. Diagonalizing the matrix product tt^ gives the transmission eigenvalues ?n, which yields the optical transmittance, T=?a,b=1^N | tba |^2 =?n=1^N ?n . The ensemble average of the transmittance is equal to the dimensionless conductance, g=. We show the probability distribution of transmittance P(T) changes from Gaussian to log-normal as the value of g decreases. The distribution P(T) is analyzed in terms of the underlying transmission eigenvalues ?n. For random samples with g˜3.9, we found P(T) follows a Gaussian distribution. For g˜0.37, we observe a highly asymmetric distribution for --lnT. The sharp drop for high values of T is attributed to the restriction that ?n<1 and the repulsion between transmission eigenvalues even for localized samples. For g˜0.04, the distribution of transmittance is nearly log-normal. The variance of -lnT, ?^2, scales linearly with <-lnT> as predicted by single parameter scaling even for weakly localized waves.

Shi, Zhou; Wang, Jing; Genack, Azriel

2012-02-01

45

Electronic excitation spectra of the five-orbital Anderson impurity model: From the atomic limit to itinerant atomic magnetism  

NASA Astrophysics Data System (ADS)

We study the competition of Coulomb interaction and hybridization effects in the five-orbital Anderson impurity model by means of continuous time quantum Monte Carlo, exact diagonalization, and Hartree-Fock calculations. The dependence of the electronic excitation spectra and thermodynamic ground-state properties on the hybridization strength and the form of the Coulomb interaction is systematically investigated for impurity occupation number N ?6. With increasing hybridization strength, a Kondo resonance emerges, broadens and merges with some of the upper and lower Hubbard peaks. Concomitantly, there is an increase of charge fluctuations at the impurity site. In contrast to the single-orbital model, some atomic multiplet peaks and exchange split satellites persist despite strong charge fluctuations. We find that Hund's coupling leads to a state that may be characterized as an itinerant single atom magnet. As the filling is increased, the magnetic moment decreases, but the spin freezing phenomenon persists up to N ?8. When the hybridization is weak, the positions of atomic ionization peaks are rather sensitive to shifts of the impurity on-site energies. This allows to distinguish atomic ionization peaks from quasiparticle peaks or satellites in the electronic excitation spectra. On the methodological side we show that a comparison between the spectra obtained from Monte Carlo and exact diagonalization calculations is possible if the charge fluctuations are properly matched.

Huang, Li; Wehling, Tim O.; Werner, Philipp

2014-06-01

46

Variational Monte Carlo study of Anderson localization in the Hubbard model  

NASA Astrophysics Data System (ADS)

We have studied the effects of interactions on persistent currents in half-filled and quarter-filled Hubbard models with weak and intermediate strength disorder. Calculations are performed using a variational Gutzwiller ansatz that describes short-range correlations near the Mott transition. We apply an Aharonov-Bohm magnetic flux, which generates a persistent current that can be related to the Thouless conductance. The magnitude of the current depends on both the strength of the screened disorder potential and the strength of electron-electron correlations, and the Anderson localization length can be extracted from the scaling of the current with system size. At half-filling, the persistent current is reduced by strong correlations when the interaction strength is large. Surprisingly, we find that the disorder potential is strongly screened in the large interaction limit, so that the localization length grows with increasing interaction strength even as the magnitude of the current is suppressed. This supports earlier dynamical mean-field-theory predictions that the elastic scattering rate is suppressed near the Mott transition.

Farhoodfar, A.; Gooding, R. J.; Atkinson, W. A.

2011-11-01

47

Commensurability effects in one-dimensional Anderson localization: Anomalies in eigenfunction statistics  

NASA Astrophysics Data System (ADS)

The one-dimensional (1d) Anderson model (AM), i.e. a tight-binding chain with random uncorrelated on-site energies, has statistical anomalies at any rational point f=2a/?E, where a is the lattice constant and ?E is the de Broglie wavelength. We develop a regular approach to anomalous statistics of normalized eigenfunctions ?( r) at such commensurability points. The approach is based on an exact integral transfer-matrix equation for a generating function ?r( u, ?) ( u and ? have a meaning of the squared amplitude and phase of eigenfunctions, r is the position of the observation point). This generating function can be used to compute local statistics of eigenfunctions of 1d AM at any disorder and to address the problem of higher-order anomalies at f={p}/{q} with q > 2. The descender of the generating function Pr(?)??r(u=0,?) is shown to be the distribution function of phase which determines the Lyapunov exponent and the local density of states. In the leading order in the small disorder we derived a second-order partial differential equation for the r-independent ("zero-mode") component ?( u, ?) at the E = 0 ( f={1}/{2}) anomaly. This equation is nonseparable in variables u and ?. Yet, we show that due to a hidden symmetry, it is integrable and we construct an exact solution for ?( u, ?) explicitly in quadratures. Using this solution we computed moments Im = N ( m ? 1) for a chain of the length N ? ? and found an essential difference between their m-behavior in the center-of-band anomaly and for energies outside this anomaly. Outside the anomaly the "extrinsic" localization length defined from the Lyapunov exponent coincides with that defined from the inverse participation ratio ("intrinsic" localization length). This is not the case at the E = 0 anomaly where the extrinsic localization length is smaller than the intrinsic one. At E = 0 one also observes an anomalous enhancement of large moments compatible with existence of yet another, much smaller characteristic length scale.

Kravtsov, V. E.; Yudson, V. I.

2011-07-01

48

Giant fluctuations of local magnetoresistance of organic spin valves and the non-Hermitian 1D Anderson model.  

PubMed

Motivated by recent experiments, where the tunnel magnetoresitance (TMR) of a spin valve was measured locally, we theoretically study the distribution of TMR along the surface of magnetized electrodes. We show that, even in the absence of interfacial effects (like hybridization due to donor and acceptor molecules), this distribution is very broad, and the portion of area with negative TMR is appreciable even if on average the TMR is positive. The origin of the local sign reversal is quantum interference of subsequent spin-rotation amplitudes in the course of incoherent transport of carriers between the source and the drain. We find the distribution of local TMR exactly by drawing upon formal similarity between evolution of spinors in time and of the reflection coefficient along a 1D chain in the Anderson model. The results obtained are confirmed by the numerical simulations. PMID:24949781

Roundy, R C; Nemirovsky, D; Kagalovsky, V; Raikh, M E

2014-06-01

49

Localized excitations of charged dust grains in dusty plasma lattices  

SciTech Connect

The nonlinear aspects of charged dust grain motion in a one-dimensional dusty plasma (DP) monolayer are discussed. Both horizontal (longitudinal, acoustic mode) and vertical (transverse, optic mode) displacements are considered, and various types of localized excitations are reviewed, in a continuum approximation. Dust crystals are shown to support nonlinear kink-shaped supersonic longitudinal solitary excitations, as well as modulated envelope (either longitudinal or transverse) localized modes. The possibility for Discrete Breather (DB-) type excitations (Intrinsic Localized Modes, ILMs) to occur is investigated, from first principles. These highly localized excitations owe their existence to lattice discreteness, in combination with the interaction and/or substrate (sheath) potential nonlinearity. This possibility may open new directions in DP- related research. The relation to previous results on atomic chains as well as to experimental results on strongly-coupled dust layers in gas discharge plasmas is discussed.

Kourakis, Ioannis; Shukla, Padma Kant [Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Basios, Vassileios [U.L.B. - Universite Libre de Bruxelles, Centre for Nonlinear Phenomena and Complex Systems, C.P. 231 Physique Statistique et Plasmas, Boulevard du Triomphe, B-1050 Brussels (Belgium)

2005-10-31

50

Anderson wall and Bloch oscillations in molecular rotation  

E-print Network

We describe a universal behavior of linear molecules excited by a periodic train of short laser pulses under quantum resonance conditions. In a rigid rotor the resonance causes an unlimited ballistic growth of the angular momentum. We show that the centrifugal distortion of rotating molecules eventually halts the growth, by causing Anderson localization beyond a critical value of the angular momentum -- the Anderson wall. Its position solely depends on the molecular rotational constants and lies in the range of a few tens of hbar. Below the wall, rotational excitation oscillates with the number of pulses due to a mechanism similar to Bloch oscillations in crystalline solids. We suggest optical experiments capable of observing the rotational Anderson wall and Bloch oscillations at near-ambient conditions with the help of existing laser technology.

Johannes Floß; Ilya Sh. Averbukh

2014-05-15

51

Observation of Infinite-Range Intensity Correlations above, at, and below the Mobility Edges of the 3D Anderson Localization Transition  

NASA Astrophysics Data System (ADS)

We investigate long-range intensity correlations on both sides of the Anderson transition of classical waves in a three-dimensional disordered material. Our ultrasonic experiments are designed to unambiguously detect a recently predicted infinite-range C0 contribution, due to local density of states fluctuations near the source. We find that these C0 correlations, in addition to C2 and C3 contributions, are significantly enhanced near mobility edges. Separate measurements of the inverse participation ratio reveal a link between C0 and the anomalous dimension ?2, implying that C0 may also be used to explore the critical regime of the Anderson transition.

Hildebrand, W. K.; Strybulevych, A.; Skipetrov, S. E.; van Tiggelen, B. A.; Page, J. H.

2014-02-01

52

Magnetoresistance of an Anderson Insulator of Bosons  

NASA Astrophysics Data System (ADS)

We study the magnetoresistance of two-dimensional bosonic Anderson insulators. We describe the change in spatial decay of localized excitations in response to a magnetic field, which is given by an interference sum over alternative tunneling trajectories. The excitations become more localized with increasing field (in sharp contrast to generic fermionic excitations which get weakly delocalized): the localization length ?(B) is found to change as ?-1(B)-?-1(0)˜B4/5. The quantum interference problem maps onto the classical statistical mechanics of directed polymers in random media (DPRM). We explain the observed scaling using a simplified droplet model which incorporates the nontrivial DPRM exponents. Our results have implications for a variety of experiments on magnetic-field-tuned superconductor-to-insulator transitions observed in disordered films, granular superconductors, and Josephson junction arrays, as well as for cold atoms in artificial gauge fields.

Gangopadhyay, Anirban; Galitski, Victor; Müller, Markus

2013-07-01

53

Mean excitation energies of atoms using the local plasma approximation  

Microsoft Academic Search

Mean excitation energies of atoms have been calculated based on a local plasma approximation. A treatment for atomic shell-wise contributions to the mean excitation energy has been established. The effect of plasma damping was included by an empirical approach. Electron density distributions of atoms have been obtained using the Hartree-Fock-Slater model. Results of this work are compared with those of

C. J. Tung; R. L. Shyu; C. M. Kwei

1988-01-01

54

Quantum entanglement of localized excited states at finite temperature  

NASA Astrophysics Data System (ADS)

In this work we study the time evolutions of (Renyi) entanglement entropy of locally excited states in two dimensional conformal field theories (CFTs) at finite temperature. We consider excited states created by acting with local operators on thermal states and give both field theoretic and holographic calculations. In free field CFTs, we find that the growth of Renyi entanglement entropy at finite temperature is reduced compared to the zero temperature result by a small quantity proportional to the width of the localized excitations. On the other hand, in finite temperature CFTs with classical gravity duals, we find that the entanglement entropy approaches a characteristic value at late time. This behaviour does not occur at zero temperature. We also study the mutual information between the two CFTs in the thermofield double (TFD) formulation and give physical interpretations of our results.

Caputa, Pawel; Simón, Joan; Štikonas, Andrius; Takayanagi, Tadashi

2015-01-01

55

Anderson localization through Polyakov loops: Lattice evidence and random matrix model  

Microsoft Academic Search

We investigate low-lying fermion modes in SU(2) gauge theory at temperatures above the phase transition. Both staggered and overlap spectra reveal transitions from chaotic (random matrix) to integrable (Poissonian) behavior accompanied by an increasing localization of the eigenmodes. We show that the latter are trapped by local Polyakov loop fluctuations. Islands of such ``wrong'' Polyakov loops can therefore be viewed

Falk Bruckmann; Tamás G. Kovács; Sebastian Schierenberg

2011-01-01

56

Novel Localized Excitations of Nonlinear Coupled Scalar Fields  

NASA Astrophysics Data System (ADS)

Some extended solution mapping relations of the nonlinear coupled scalar field and the well-known phi4 model are presented. Simultaneously, inspired by the new solutions of the famous phi4 model recently proposed by Jia, Huang and Lou, five kinds of new localized excitations of the nonlinear coupled scalar field (NCSF) system are obtained.

Li, Jin-Hua; Wu, Huang-Jiao

2008-06-01

57

Suppression of Anderson localization of light in one-dimensional disordered photonic superlattices  

NASA Astrophysics Data System (ADS)

The localization properties of electromagnetic modes in one-dimensional disordered photonic superlattices are theoretically studied. The multilayered system is considered to be composed of alternating stacks of two different random-thickness slabs, characterized by nondispersive and/or frequency-dependent electric permittivities and magnetic permeabilities. Results for the localization length are evaluated by using an analytical model for weakly disordered systems as well as its general definition through the transmissivity properties of the heterostructure. Good agreement between both results is observed only for small amplitudes of disorder. The critical frequencies at which the localization length diverges are correctly predicted in the whole frequency spectrum by the analytical model and confirmed via the corresponding numerical calculations. The ?2 dependence of the localization length, previously observed in disordered heterostructures made of material of positive refractive indexes, are confirmed in the present work. In addition, new ?4 and ?-4 dependencies of the localization length in positive-negative disordered photonic superlattices are obtained, under certain specific conditions, in the long and short wavelength limits, respectively. The asymptotic behavior of the localization length in these limits is essentially determined by the particular frequency dispersion that characterizes the metamaterial used in the left-handed layers. When the effects of absorption are considered, then a divergence of the localization length is still observed, under some conditions, in the short wavelength limit.

Reyes-Gómez, E.; Bruno-Alfonso, A.; Cavalcanti, S. B.; Oliveira, L. E.

2012-05-01

58

Local and Regional Staging of Invasive Breast Cancer With Sonography: 25 Years of Practice at MD Anderson Cancer Center  

PubMed Central

At The University of Texas MD Anderson Cancer Center, we have used sonography (US) extensively for more than 2 decades to refine the local and regional staging of invasive breast cancer. Although magnetic resonance imaging is superior to all other imaging modalities in the measurement of the primary tumor and detection of additional foci of malignancy, in our experience US has shown sufficient accuracy in clinical practice to stage most invasive breast cancers. The exceptions are ill-defined tumors such as invasive lobular cancers and tumors in breasts containing extensive diffuse benign disease. An advantage of US is that multifocality or multicentricity can be confirmed via US-guided fine-needle aspiration within 15 minutes and the information shared immediately with the patient and the breast surgeon or medical oncologist. US has also proved indispensable in the evaluation of lymphatic spread because it can evaluate more nodal basins (e.g., the supraclavicular fossa and low neck) than magnetic resonance imaging can and because it can guide needle biopsy to confirm the status of any indeterminate node (including internal mammary nodes) within minutes. PMID:24309983

2014-01-01

59

The Anderson Transition  

Microsoft Academic Search

An outline is given of the electrical properties expected in a disordered solid or fluid which shows a metal-insulator transition of Anderson type. This is one in which the Fermi energy of the electrons passes through a mobility edge separating extended states from states localized by disorder, as the composition or some other parameter is changed. Some of the experimental

Nevill Mott; M. Pepper; S. Pollitt; R. H. Wallis; C. J. Adkins

1975-01-01

60

Wireless Sensor Network Localization Techniques Guoqiang Mao, Baris Fidan and Brian D.O. Anderson  

E-print Network

interest. Recent advances in wireless communications and electronics have enabled the development of low monitoring, health monitoring, reconnaissance and surveillance. Sensor network localization algorithms network in the global coordinate system. G. Mao is with the University of Sydney and National ICT

Scheuermann, Peter

61

PHYSICAL REVIEW B 85, 045122 (2012) Transmission and Anderson localization in dispersive metamaterials  

E-print Network

metamaterials Ara A. Asatryan,1 Lindsay C. Botten,1 Michael A. Byrne,1 Valentin D. Freilikher,2 Sergey A, one-dimensional stacks composed of dispersive metamaterials and normal materials are presented that the localization of waves in random stacks composed entirely of either metamaterial or normal dielectric layers

62

Anderson localization of matter waves in three-dimensional anisotropic disordered potentials  

NASA Astrophysics Data System (ADS)

Using a cutoff-free formulation of the coherent transport theory, we show that the interference terms at the origin of localization strongly affect the transport anisotropy. In contrast to the common hypothesis, we then find that the anisotropies of incoherent and coherent diffusion are significantly different, in particular at criticality. There, we show that the coherent transport anisotropy is mainly determined by the properties of the disorder-averaged effective scattering medium while the incoherent transport contributions become irrelevant.

Piraud, Marie; Sanchez-Palencia, Laurent; van Tiggelen, Bart

2014-12-01

63

Anderson Localization of Ballooning Modes, Quantum Chaos and the Stability of Compact Quasiaxially Symmetric Stellarators  

SciTech Connect

The radially local magnetohydrodynamic (MHD) ballooning stability of a compact, quasiaxially symmetric stellarator (QAS), is examined just above the ballooning beta limit with a method that can lead to estimates of global stability. Here MHD stability is analyzed through the calculation and examination of the ballooning mode eigenvalue isosurfaces in the 3-space [s, alpha, theta(subscript ''k'')]; s is the edge normalized toroidal flux, alpha is the field line variable, and q(subscript ''k'') is the perpendicular wave vector or ballooning parameter. Broken symmetry, i.e., deviations from axisymmetry, in the stellarator magnetic field geometry causes localization of the ballooning mode eigenfunction, and gives rise to new types of nonsymmetric eigenvalue isosurfaces in both the stable and unstable spectrum. For eigenvalues far above the marginal point, isosurfaces are topologically spherical, indicative of strong ''quantum chaos.'' The complexity of QAS marginal isosurfaces suggests that finite Larmor radius stabilization estimates will be difficult and that fully three-dimensional, high-n MHD computations are required to predict the beta limit.

M.H. Redi; J.L. Johnson; S. Klasky; J. Canik; R.L. Dewar; W.A. Cooper

2001-10-31

64

Weak chaos in the disordered nonlinear Schroedinger chain: Destruction of Anderson localization by Arnold diffusion  

SciTech Connect

Research Highlights: > In a one-dimensional disordered chain of oscillators all normal modes are localized. > Nonlinearity leads to chaotic dynamics. > Chaos is concentrated on rare chaotic spots. > Chaotic spots drive energy exchange between oscillators. > Macroscopic transport coefficients are obtained. - Abstract: The subject of this study is the long-time equilibration dynamics of a strongly disordered one-dimensional chain of coupled weakly anharmonic classical oscillators. It is shown that chaos in this system has a very particular spatial structure: it can be viewed as a dilute gas of chaotic spots. Each chaotic spot corresponds to a stochastic pump which drives the Arnold diffusion of the oscillators surrounding it, thus leading to their relaxation and thermalization. The most important mechanism of equilibration at long distances is provided by random migration of the chaotic spots along the chain, which bears analogy with variable-range hopping of electrons in strongly disordered solids. The corresponding macroscopic transport equations are obtained.

Basko, D.M., E-mail: denis.basko@grenoble.cnrs.fr [Laboratoire de Physique et Modelisation des Milieux Condenses, Universite de Grenoble 1 and CNRS, BP166, 38042 Grenoble (France)

2011-07-15

65

Relativistic Coulomb excitation within Time Dependent Superfluid Local Density Approximation  

E-print Network

Within the framework of the unrestricted time-dependent density functional theory, we present for the first time an analysis of the relativistic Coulomb excitation of the heavy deformed open shell nucleus $^{238}$U. The approach is based on Superfluid Local Density Approximation (SLDA) formulated on a spatial lattice that can take into account coupling to the continuum, enabling self-consistent studies of superfluid dynamics of any nuclear shape. We have computed the energy deposited in the target nucleus as a function of the impact parameter, finding it to be significantly larger than the estimate using the Goldhaber-Teller model. The isovector giant dipole resonance, the dipole pygmy resonance and giant quadrupole modes were excited during the process. The one body dissipation of collective dipole modes is shown to lead a damping width $\\Gamma_\\downarrow \\approx 0.4$ MeV and the number of pre-equilibrium neutrons emitted has been quantified.

Stetcu, I; Bulgac, A; Magierski, P; Roche, K J

2014-01-01

66

Relativistic Coulomb excitation within Time Dependent Superfluid Local Density Approximation  

E-print Network

Within the framework of the unrestricted time-dependent density functional theory, we present for the first time an analysis of the relativistic Coulomb excitation of the heavy deformed open shell nucleus $^{238}$U. The approach is based on Superfluid Local Density Approximation (SLDA) formulated on a spatial lattice that can take into account coupling to the continuum, enabling self-consistent studies of superfluid dynamics of any nuclear shape. We have computed the energy deposited in the target nucleus as a function of the impact parameter, finding it to be significantly larger than the estimate using the Goldhaber-Teller model. The isovector giant dipole resonance, the dipole pygmy resonance and giant quadrupole modes were excited during the process. The one body dissipation of collective dipole modes is shown to lead a damping width $\\Gamma_\\downarrow \\approx 0.4$ MeV and the number of pre-equilibrium neutrons emitted has been quantified.

I. Stetcu; C. Bertulani; A. Bulgac; P. Magierski; K. J. Roche

2014-03-11

67

Charge transfer dynamics in molecular solids and adsorbates driven by local and non-local excitations  

NASA Astrophysics Data System (ADS)

Charge transfer pathways and charge transfer times in molecular films and in adsorbate layers depend both on the details of the electronic structure as well as on the degree of the initial localization of the propagating excited electronic state. For C6F6 molecular adsorbate films on the Cu(111) surface we determined the interplay between excited state localization and charge transfer pathways. In particular we selectively prepared a free-particle-like LUMO band excitation and compared it to a molecularly localized core-excited C1s ? ?* C6F6 LUMO state using time-resolved two-photon photoemission (tr-2PPE) and core-hole-clock (CHC) spectroscopy, respectively. For the molecularly localized core-excited C1s ? ?* C6F6 LUMO state, we separate the intramolecular dynamics from the charge transfer dynamics to the metal substrate by taking the intramolecular dynamics of the free C6F6 molecule into account. Our analysis yields a generally applicable description of charge transfer within molecular adsorbates and to the substrate.

Föhlisch, A.; Vijayalakshmi, S.; Pietzsch, A.; Nagasono, M.; Wurth, W.; Kirchmann, P. S.; Loukakos, P. A.; Bovensiepen, U.; Wolf, M.; Tchaplyguine, M.; Hennies, F.

2012-06-01

68

Localized nonlinear excitations in diffusive Hindmarsh-Rose neural networks  

NASA Astrophysics Data System (ADS)

We study localized nonlinear excitations in diffusive Hindmarsh-Rose neural networks. We show that the Hindmarsh-Rose model can be reduced to a modified Complex Ginzburg-Landau equation through the application of a perturbation technique. We equally report on the presence of envelop solitons of the nerve impulse in this neural network. From the biological point of view, this result suggests that neurons can participate in a collective processing of information, a relevant part of which is shared over all neurons but not concentrated at the single neuron level. By employing the standard linear stability analysis, the growth rate of the modulational instability is derived as a function of the wave number and systems parameters.

Moukam Kakmeni, F. M.; Inack, E. M.; Yamakou, E. M.

2014-05-01

69

Localized nonlinear excitations in diffusive Hindmarsh-Rose neural networks.  

PubMed

We study localized nonlinear excitations in diffusive Hindmarsh-Rose neural networks. We show that the Hindmarsh-Rose model can be reduced to a modified Complex Ginzburg-Landau equation through the application of a perturbation technique. We equally report on the presence of envelop solitons of the nerve impulse in this neural network. From the biological point of view, this result suggests that neurons can participate in a collective processing of information, a relevant part of which is shared over all neurons but not concentrated at the single neuron level. By employing the standard linear stability analysis, the growth rate of the modulational instability is derived as a function of the wave number and systems parameters. PMID:25353873

Moukam Kakmeni, F M; Inack, E M; Yamakou, E M

2014-05-01

70

Entanglement in Anderson Nanoclusters  

E-print Network

We investigate the two-particle spin entanglement in magnetic nanoclusters described by the periodic Anderson model. An entanglement phase diagram is obtained, providing a novel perspective on a central property of magnetic nanoclusters, namely the temperature dependent competition between local Kondo screening and nonlocal Ruderman-Kittel-Kasuya-Yoshida spin ordering. We find that multiparticle entangled states are present for finite magnetic field as well as in the mixed valence regime and away from half filling. Our results emphasize the role of charge fluctuations.

Peter Samuelsson; Claudio Verdozzi

2006-07-28

71

Entanglement in Anderson Nanoclusters  

E-print Network

We investigate the two-particle spin entanglement in magnetic nanoclusters described by the periodic Anderson model. An entanglement phase diagram is obtained, providing a novel perspective on a central property of magnetic nanoclusters, namely the temperature dependent competition between local Kondo screening and nonlocal Ruderman-Kittel-Kasuya-Yoshida spin ordering. We find that multiparticle entangled states are present for finite magnetic field as well as in the mixed valence regime and away from half filling. Our results emphasize the role of charge fluctuations.

Samuelsson, Peter

2007-01-01

72

Modeling of ion-acoustic soliton excitation through decay process of a localized perturbation  

Microsoft Academic Search

The possibility of the nonlinear decay of a localized perturbation into the ion-acoustic solitons is studied. The present paper is a theoretical attempt to model the experimental soliton excitation [S. Yi et al., Phys. Plasmas 4, 2436 (1997)] in which solitons are excited by a grid modulating near the ion plasma frequency. It has been reported that a localized wave

H. Hakimi Pajouh; H. Abbasi

2008-01-01

73

Leona Anderson Oral History  

E-print Network

Oral history interview with Leona Anderson conducted by Rachel Gadd-Nelson in Burdick, Kansas, on September 18, 2009. In this interview, Leona Anderson discusses her experiences as a member of the Missouri Synod Lutheran Church in Lattimer, Kansas...

Anderson, Leona; Gadd-Nelson, Rachel

2009-09-18

74

Bulk and local elastic relaxation around optically excited centers  

NASA Astrophysics Data System (ADS)

The macroscopic refractive effect arising from an optically excited Cr3+ center in a Gd-Sc-Ga garnet crystal was observed and measured using time-resolved beam-deflection spectroscopy. The excited-state effect is much larger than the thermal effect. The predominant mechanism is concluded to be the refractive effect stemming from the elastic dilation of the CrO6 cluster in the excited 4T2 state of Cr3+. The bulk expansion per excited ion is ~=12 Aṧ. An expansion of ~=0.13 Å of the oxygen coordination sphere is derived in the approximation of an isotropic elastic continuum and a fully symmetric dilation. This displacement is in agreement with the optical spectra in the framework of the configuration coordinate model.

Strauss, Eugen

1990-08-01

75

The Anderson Quin Cycle  

Microsoft Academic Search

The objective of this study was to make a more refined evaluation of the Anderson Quin Cycle based on most recent information on the performance of various elements that will be used in the Anderson Quin Cycle. My original estimate of the work plan for evaluating and optimizing the Anderson Quin Cycle called for 7000 man hours of work. Since

J. H. Anderson; W. M. Bilbow

1993-01-01

76

Excitation by Local Electric Fields in the Aurora and Airglow  

Microsoft Academic Search

We have developed a method for accurate calculation of the distribution of electron energies in the ionosphere under the influence of an electric field. From this calculation we can predict rates of excitation of radiating states of N., O., and O as a function of the strength of a hypothetical applied field. We find that it is unreasonable to expect

L. R. Megill; N. P. Carleton

1964-01-01

77

Local liquid crystal alignment on patterned micrograting structures photofabricated by two photon excitation direct laser writing  

Microsoft Academic Search

The authors demonstrate local alignment of nematic liquid crystal through the fabrication of local micrograting structures by curing an ultraviolet curable material via a two-photon excitation laser-lithography process. A local twisted-nematic region was prepared using one rubbed and one fabricated micrograting surface and the resulting cell was observed with a polarizing optical microscope. The polarization optical micrographs of the locally

Chee Heng Lee; Hiroyuki Yoshida; Yusuke Miura; Akihiko Fujii; Masanori Ozaki

2008-01-01

78

Control of electron localization in highly excited states with two ultraviolet laser pulses  

NASA Astrophysics Data System (ADS)

We propose and demonstrate a scheme for controlling the electron localization in the dissociating H2+ in highly excited states. The control is achieved through two steps: the excitation and the coupling of the electronic wavepackets. Firstly, the excitation is triggered by an ultraviolet laser pulse with a critical wavelength, in which the wavepackets can be launched to the highly excited state (2s{{? }g}) efficiently from the ground state (1s{{? }g}). Then, we utilize a second time-delayed ultraviolet laser pulse to manipulate the population of the degenerate state (3p{{? }u}) around the one-photon coupling region. Our results show that, by adjusting the time delay between the two pulses and the carrier–envelope phase of the second pulse, the control of electron localization of H2+ in highly excited states can be achieved.

Wang, Zhuo; Liu, Kunlong; Lan, Pengfei; Lu, Peixiang

2015-01-01

79

Conductive optical-fiber STM probe for local excitation and collection of cathodoluminescence at semiconductor surfaces.  

PubMed

Luminescence imaging of semiconductor surfaces in nanometric resolution is a key to novel optoelectronic nano-devices, which requires local carrier excitation and local luminescence collection within the nanometric areas at the surfaces. However, there have not been a practical nanospectroscopies applicable to wide range of specimens. STM-cathodoluminescence (STM-CL) nanospectroscopy offers both high spatial resolution (of the order of 10 nm) and novel high carrier excitation power (up to ~1 mW), which enables local luminescence imaging of less-luminescent nano-structures. In this study, we advanced STM-CL technique by introducing a novel optical fiber probe with Cr thin film coating (Cr-FP), which was found to work as a STM probe, as an electron field-emitter for local carrier excitation, and as an alignment-free efficient local STM-CL collector which blinds luminescence after the minority carrier diffusion. PMID:23938843

Watanabe, Kentaro; Nakamura, Yoshiaki; Ichikawa, Masakazu

2013-08-12

80

Local excitations in thin metal films bounded by topological insulators  

NASA Astrophysics Data System (ADS)

Electromagnetic excitations arising in a metal slab surrounded by an insulator with a non-trivial topology associated to time reversal symmetry (topological insulator) are described. It is shown that the topological term induces modifications to the dispersion relations of bounding and antibounding surface modes in the long wavelength non-retarded limit which depend on the square of the topological term. In particular, it is shown that a backward wave arises with a group velocity undergoing a relative change which is independent of the film thickness. It is shown that the rotation of the polarization plane induced by the non-trivial topology is a linear function of the topological term for all slab thickness.

Granada E, J. C.; Rojas, D. F.

2014-12-01

81

Collision broadened resonance localization in tokamaks excited with ICRF waves  

SciTech Connect

Advanced wave models used to evaluate ICRH in tokamaks typically use warm plasma theory and allow inhomogeneity in one dimension. The authors have developed a bounce-averaged Fokker-Planck quasilinear computational model which evolves the population of particles on more realistic orbits. Each wave-particle resonance has its own specific interaction amplitude within any given volume element. These data need only be generated once, and appropriately stored for efficient retrieval. The wave-particle resonant interaction then serves as a mechanism by which the diffusion of particle populations can proceed among neighboring orbits. Collisions affect the absorption of rf energy by two quite distinct processes: In addition to the usual relaxation towards the Maxwellian distribution creating velocity gradients which drive quasilinear diffusion, collisions also affect the wave-particle resonance through the mechanism of gyro-phase diffusion. The local specific spectral energy absorption rate is directly calculable once the orbit geometry and populations are determined. The code is constructed in such fashion as to accommodate wave propagation models which provide the wave spectral energy density on a poloidal cross-section. Information provided by the calculation includes the local absorption properties of the medium which can then be exploited to evolve the wave field.

Kerbel, G.D.; McCoy, M.G.

1985-08-01

82

Local bifurcations of synchronization in self-excited and forced unidirectionally coupled micromechanical resonators  

NASA Astrophysics Data System (ADS)

A unidirectionally coupled system of Microelectromechanical Systems (MEMS) resonators is investigated. Local bifurcations of both the single resonator and the coupled system are analyzed in the design of the coupled system. We discuss the behavior of the coupled system according to the change in the coupling parameter and the excitation force. Phenomena such as quasiperiodic oscillations and synchronization are shown by numerical simulations and studied analytically through perturbation methods. The coupled system shows oscillatory behavior without the excitation force. In the presence of the excitation force the coupled system exhibits complex behavior which can be beneficial in the design of the coupled system as a sensor.

Naik, Suketu; Hikihara, Takashi; Vu, Huy; Palacios, Antonio; In, Visarath; Longhini, Patrick

2012-02-01

83

Investigation of RF excited CW CO2 waveguide lasers local oscillator - RF excitation  

NASA Technical Reports Server (NTRS)

A new local oscillator housing was built which seems to have improved laser life. Laser cooling was changed from internal water cooling to the more convenient thermal contact cooling. At the present time, a conclusion can not be made if the 20 percent reduction in power output is the result of poorer cooling or poorer grating alignment. The coupling-starting network was improved from 55 to about 90 percent. It can be adjusted by varying trimmers C sub 1 and C sub 2 to match RF power levels between 10 and 30 W. If the laser admittance changes greatly with laser life rematching will have to be achieved by remote control for space applications. The same holds true if the RF power level has to be changed with a maximum efficiency constraint.

Hochuli, U.

1988-01-01

84

Through-bond interactions and the localization of excited-state dynamics.  

PubMed

The influence of through-bond interactions on nonadiabatic excited-state dynamics is investigated by time-resolved photoelectron spectroscopy (TRPES) and ab initio computation. We compare the dynamics of cyclohexa-1,4-diene, which exhibits a through-bond interaction known as homoconjugation (the electronic correlation between nonconjugated double bonds), with the nonconjugated cyclohexene. Each molecule was initially excited to a 3s Rydberg state using a 200 nm femtosecond pump pulse. The TRPES spectra of these molecules display similar structure and time constants on a subpicosecond time scale. Our ab initio calculations show that similar sets of conical intersections (a [1,2]- and [1,3]-hydrogen shift, as well as carbon-carbon bond cleavage) are energetically accessible to both molecules and that the geometry and orbital composition at the minimum energy crossing points to the ground state are directly analogous. These experimental and computational results suggest that the excited-state dynamics of cyclohexa-1,4-diene become localized at a single double bond and that the effects of through-bond interaction, dominant in the absorption spectrum, are absent in the excited-state dynamics. The notion of excited-state dynamics being localized at specific sites within the nuclear framework is analogous to the localization of light absorption by a subsystem within the molecule, designated a chromophore. We propose the utility of the analogous concept, denoted here as a dynamophore. PMID:21851118

Schalk, Oliver; Boguslavskiy, Andrey E; Stolow, Albert; Schuurman, Michael S

2011-10-19

85

Rényi entropy of locally excited states with thermal and boundary effect in 2D CFTs  

E-print Network

We study R\\'enyi entropy of locally excited states with considering the thermal and boundary effects respectively in two dimensional conformal field theories (CFTs). Firstly we consider locally excited states obtained by acting primary operators on a thermal state in low temperature limit. The R\\'enyi entropy is summation of contribution from thermal effect and local excitation. Secondly, we mainly study the R\\'enyi entropy of locally excited states in 2D CFT with a boundary. We show that the evolution of R\\'enyi entropy does not depend on the choice of boundary conditions and boundary will change the time evolution of R\\'enyi entropy. Moreover, in 2D rational CFTs with a boundary, we show that the R\\'enyi entropy always coincides with the log of quantum dimension of the primary operator during some periods of the evolution. We make use of a quasi-particle picture to understand this phenomenon. In terms of quasi-particle interpretation, the boundary behaves as an infinite potential barrier which reflects any energy moving towards the boundary.

Wu-Zhong Guo; Song He

2015-01-05

86

Localized Excitations in a Sixth-Order (1+1)-Dimensional Nonlinear Evolution Equation  

NASA Astrophysics Data System (ADS)

In this letter, by means of the Lax pair, Darboux transformation, and variable separation approach, a new exact solution of a sixth-order (1+1)-dimensional nonlinear evolution equation, which includes some arbitrary functions, is obtained. Abundant new localized excitations can be found by selecting appropriate functions and they are illustrated both analytically and graphically.

Shen, Shou-Feng

2005-12-01

87

Local excitation of strongly coupled exciton-surface plasmons polaritons by a single nanoantenna  

SciTech Connect

We demonstrate experimentally local coupling of light from free space to exciton-surface plasmon polaritons (X-SPPs). This is achieved by using a single, sub-wavelength gold nanowire on top of a thin silver film which is covered with a 30?nm thick layer of J-aggregating dyes in polyvinyl alcohol. We show that the nanowire acts as an antenna that resonantly scatters light to X-SPPs states with a Rabi splitting of 0.1?eV. The locally excited X-SPPs properties are studied by angle resolved spectroscopy of the far-field leaky photons and are compared to the large-scale response through Kretschmann reflection measurements and to theoretical calculations. The nanowire scattering properties are studied by dark-field scattering measurements and finite-difference time-domain simulations. This method to locally excite X-SPPs can potentially be useful for future applications of hybrid light matter states.

Eizner, E., E-mail: eladeiz@post.tau.ac.il; Ellenbogen, T. [Department of Physical Electronics, Fleischman Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel)

2014-06-02

88

Local excitation of strongly coupled exciton-surface plasmons polaritons by a single nanoantenna  

NASA Astrophysics Data System (ADS)

We demonstrate experimentally local coupling of light from free space to exciton-surface plasmon polaritons (X-SPPs). This is achieved by using a single, sub-wavelength gold nanowire on top of a thin silver film which is covered with a 30 nm thick layer of J-aggregating dyes in polyvinyl alcohol. We show that the nanowire acts as an antenna that resonantly scatters light to X-SPPs states with a Rabi splitting of 0.1 eV. The locally excited X-SPPs properties are studied by angle resolved spectroscopy of the far-field leaky photons and are compared to the large-scale response through Kretschmann reflection measurements and to theoretical calculations. The nanowire scattering properties are studied by dark-field scattering measurements and finite-difference time-domain simulations. This method to locally excite X-SPPs can potentially be useful for future applications of hybrid light matter states.

Eizner, E.; Ellenbogen, T.

2014-06-01

89

Localization of Dirac-like excitations in graphene in the presence of smooth inhomogeneous magnetic fields  

E-print Network

The present article discusses magnetic confinement of the Dirac excitations in graphene in presence of inhomogeneous magnetic fields. In the first case a magnetic field directed along the z axis whose magnitude is proportional to $1/r$ is chosen. In the next case we choose a more realistic magnetic field which does not blow up at the origin and gradually fades away from the origin. The magnetic fields chosen do not have any finite/infinite discontinuity for finite values of the radial coordinate. The novelty of the two magnetic fields is related to the equations which are used to find the excited spectra of the excitations. It turns out that the bound state solutions of the two-dimensional hydrogen atom problem are related to the spectra of graphene excitations in presence of the $1/r$ (inverse-radial) magnetic field. For the other magnetic field profile one can use the knowledge of the bound state spectrum of a two-dimensional cut-off Coulomb potential to dictate the excitation spectra of the states of graphene. The spectrum of the graphene excitations in presence of the inverse-radial magnetic field can be exactly solved while the other case cannot be. In the later case we give the localized solutions of the zero-energy states in graphene.

Pratim Roy; Tarun Kanti Ghosh; Kaushik Bhattacharya

2011-12-14

90

Localization of Dirac-like excitations in graphene in the presence of smooth inhomogeneous magnetic fields.  

PubMed

The present paper discusses magnetic confinement of the Dirac excitations in graphene in the presence of inhomogeneous magnetic fields. In the first case a magnetic field directed along the z axis whose magnitude is proportional to 1/r is chosen. In the next case we choose a more realistic magnetic field which does not blow up at the origin and gradually fades away from the origin. The magnetic fields chosen do not have any finite/infinite discontinuity for finite values of the radial coordinate. The novelty of the two magnetic fields is related to the equations which are used to find the excited spectra of the excitations. It turns out that the bound state solutions of the two-dimensional hydrogen atom problem are related to the spectra of graphene excitations in the presence of the 1/r (inverse-radial) magnetic field. For the other magnetic field profile one can use the knowledge of the bound state spectrum of a two-dimensional cutoff Coulomb potential to dictate the excitation spectra of graphene. The spectrum of the graphene excitations in the presence of the inverse-radial magnetic field can be exactly solved while the other case cannot be. In the later case we give the localized solutions of the zero-energy states in graphene. PMID:22227414

Roy, Pratim; Ghosh, Tarun Kanti; Bhattacharya, Kaushik

2012-02-01

91

Excite  

NSDL National Science Digital Library

Hot on the heels of AltaVista's Raging Search (see the May 5, 2000 Scout Report) comes another returned and (somewhat) slimmed-down search engine that focuses on relevant results. Like Raging Search, Excite's new Precision Search uses Google-style link analysis technology ("Deep Analysis") to help identify the most useful sites. Test queries produced consistently relevant results among the top few returns, though an indication of the number of total returns would be helpful, with two banner ads and (in some but not all cases) a Quick Results box on the left that could be quite handy for consumer-related searching. For instance, a search for "Plymouth" yielded links to research and comparisons, blue book values, financing, and service and repair information in the Quick Results box. I was also pleased to see that clicking on one of the other search categories (category, news, photo, audio/video) instantly produces returns for the original query, though the photo databases available seem somewhat limited compared to, say, AltaVista. While users searching for "official" sites will still do best at Google, those who also search for additional resources such as news, photos, and audio/video content may wish to give Excite Precision a run-through.

92

PUBLICATIONS GREG W. ANDERSON  

E-print Network

PUBLICATIONS GREG W. ANDERSON Books An introduction to random matrices, Cambridge studies University Press 2011 (ISBN 978-0-19-957400-1) Articles in refereed journals (1) Logarithmic derivatives 311 (S´erie I, 1990)469­472. (16) A short proof of Selberg's generalized beta formula. Forum Math. 3

Anderson, Greg W.

93

LES of a Jet Excited by the Localized Arc Filament Plasma Actuators  

NASA Technical Reports Server (NTRS)

The fluid dynamics of a high-speed jet are governed by the instability waves that form in the free-shear boundary layer of the jet. Jet excitation manipulates the growth and saturation of particular instability waves to control the unsteady flow structures that characterize the energy cascade in the jet.The results may include jet noise mitigation or a reduction in the infrared signature of the jet. The Localized Arc Filament Plasma Actuators (LAFPA) have demonstrated the ability to excite a high-speed jets in laboratory experiments. Extending and optimizing this excitation technology, however, is a complex process that will require many tests and trials. Computational simulations can play an important role in understanding and optimizing this actuator technology for real-world applications. Previous research has focused on developing a suitable actuator model and coupling it with the appropriate computational fluid dynamics (CFD) methods using two-dimensional spatial flow approximations. This work is now extended to three-dimensions (3-D) in space. The actuator model is adapted to a series of discrete actuators and a 3-D LES simulation of an excited jet is run. The results are used to study the fluid dynamics near the actuator and in the jet plume.

Brown, Clifford A.

2011-01-01

94

Controlled propagation of locally excited vortex dynamics in linear nanomagnet arrays  

NASA Astrophysics Data System (ADS)

The ability to propagate local electromagnetic excitation in a medium with spatially modulated physical properties is important for fundamental science and also for applications in photonic, phononic and magnonic crystals. Here, we present a controlled propagation of locally excited magnetic vortex dynamics through a linear array of nanomagnetic discs by controlling the polarization, chirality and shape of the discs. The control is based upon the magnetostatic interaction between the nanodiscs, mediated by the magnetic side charges generated by the gyrating vortices. The magnitude and sign of the side charges and their separation depend strongly on the magnetic ground states of the vortices, including the core polarization and the chirality. We find that the transmission of peak amplitude and velocity of propagation of the excitation along the array is optimized for identical core polarization and chirality of the nanodiscs with geometric asymmetry. More than seven times increase in the transmitted amplitude is observed in the optimized structure as opposed to the non-optimized structure, which is also found to be robust to defects.

Barman, Saswati; Barman, Anjan; Otani, Y.

2010-08-01

95

Core excitation in O3 localized to one of two symmetry-equivalent chemical bonds: molecular alignment through vibronic coupling.  

PubMed

Core excitation from terminal oxygen OT in O3 is shown to be an excitation from a localized core orbital to a localized valence orbital. The valence orbital is localized to one of the two equivalent chemical bonds. We experimentally demonstrate this with the Auger-Doppler effect which is observable when O3 is core excited to the highly dissociative OT1s(-1)7a1 1 state. Auger electrons emitted from the atomic oxygen fragment carry information about the molecular orientation relative to the electromagnetic-field vector at the moment of excitation. The data together with analytical functions for the electron-peak profiles give clear evidence that the preferred molecular orientation for excitation only depends on the orientation of one bond, not on the total molecular orientation. The localization of the valence orbital "7a1" is caused by mixing of the valence orbital "5b2" through vibronic coupling of antisymmetric stretching mode with b2 symmetry. To the best of our knowledge, it is the first discussion of the localization of a core excitation of O3. This result explains the success of the widely used assumption of localized core excitation in adsorbates and large molecules. PMID:15945631

Wiesner, K; Naves de Brito, A; Sorensen, S L; Kosugi, N; Björneholm, O

2005-04-15

96

Localization of nonlinear damage using state-space-based predictions under stochastic excitation  

NASA Astrophysics Data System (ADS)

This paper presents a study on localizing damage under stochastic excitation by state-space-based methods, where the damaged response contains some nonlinearity. Two state-space-based modeling algorithms, namely auto- and cross-predictions, are employed in this paper, and the greatest prediction error will be achieved at the sensor pair closest to the actual damage, in terms of localization. To quantify the distinction of prediction error distributions obtained at different sensor locations, the Bhattacharyya distance is adopted as the quantification metric. There are two lab-scale test-beds adopted as validation platforms, including a two-story plane steel frame with bolt loosening damage and a three-story benchmark aluminum frame with a simulated tunable crack. Band-limited Gaussian noise is applied through an electrodynamic shaker to the systems. Testing results indicate that the damage detection capability of the state-space-based method depends on the nonlinearity-induced high frequency responses. Since those high frequency components attenuate quickly in time and space, the results show great capability for damage localization, i.e., the highest deviation of Bhattacharyya distance is coincident with the sensors close to the physical damage location. This work extends the state-space-based damage detection method for localizing damage to a stochastically excited scenario, which provides the advantage of compatibility with ambient excitations. Moreover, results from both experiments indicate that the state-space-based method is only sensitive to nonlinearity-induced damage, thus it can be utilized in parallel with linear classifiers or normalization strategies to insulate the operational and environmental variability, which often affects the system response in a linear fashion.

Liu, Gang; Mao, Zhu; Todd, Michael; Huang, Zongming

2014-02-01

97

The Anderson Quin Cycle  

SciTech Connect

The objective of this study was to make a more refined evaluation of the Anderson Quin Cycle based on most recent information on the performance of various elements that will be used in the Anderson Quin Cycle. My original estimate of the work plan for evaluating and optimizing the Anderson Quin Cycle called for 7000 man hours of work. Since this grant was limited to 2150 man hours, we could not expect to achieve all the objectives within the allotted period of work. However, the most relevant program objectives have been completed as reported here. The analysis generally confirms the results originally estimated in my paper on the subject. (Ref. 2) Further optimizations should show even higher efficiencies. The Anderson Quin Cycle (US Patent applied for) basically consists of 5 elements in the power cycle: A refrigeration system to cool and clean the inlet air before it enters the compressor that supplies air for the gas turbine; a gas turbine consisting of a compressor, combustor, and turbine; a steam boiler and steam turbine system using the heat from the exhaust gas out of the gas turbine; a vapor turbine cycle, which utilizes the condensed heat from the exhaust of the steam turbine and the exhaust gas heat leaving the steam boiler to operate a vapor turbine cycle which utilizes another fluid than water, in this case isobutane; and the fifth element consists of a gas cooler and heat pump system, which removes the heat from the exhaust gas to lower its temperature essentially to atmospheric temperature, and at the same time permits treatment of the exhaust gas to remove acid components such as sulfur dioxide and nitrogen oxides. Current industry accepted component characteristics were incorporated in the performance analysis of the overall cycle, ensuring accurate and meaningful operating predictions. The characteristics and performance of each of the elements are described. The thermal efficiency of the optimized calculated Anderson Quin Cycle is 62 percent.

Anderson, J.H.; Bilbow, W.M.

1993-03-18

98

Relativistic Coulomb Excitation within the Time Dependent Superfluid Local Density Approximation.  

PubMed

Within the framework of the unrestricted time-dependent density functional theory, we present for the first time an analysis of the relativistic Coulomb excitation of the heavy deformed open shell nucleus ^{238}U. The approach is based on the superfluid local density approximation formulated on a spatial lattice that can take into account coupling to the continuum, enabling self-consistent studies of superfluid dynamics of any nuclear shape. We compute the energy deposited in the target nucleus as a function of the impact parameter, finding it to be significantly larger than the estimate using the Goldhaber-Teller model. The isovector giant dipole resonance, the dipole pygmy resonance, and giant quadrupole modes are excited during the process. The one-body dissipation of collective dipole modes is shown to lead a damping width ?_{?}?0.4??MeV and the number of preequilibrium neutrons emitted has been quantified. PMID:25615463

Stetcu, I; Bertulani, C A; Bulgac, A; Magierski, P; Roche, K J

2015-01-01

99

Relativistic Coulomb Excitation within the Time Dependent Superfluid Local Density Approximation  

NASA Astrophysics Data System (ADS)

Within the framework of the unrestricted time-dependent density functional theory, we present for the first time an analysis of the relativistic Coulomb excitation of the heavy deformed open shell nucleus 238U. The approach is based on the superfluid local density approximation formulated on a spatial lattice that can take into account coupling to the continuum, enabling self-consistent studies of superfluid dynamics of any nuclear shape. We compute the energy deposited in the target nucleus as a function of the impact parameter, finding it to be significantly larger than the estimate using the Goldhaber-Teller model. The isovector giant dipole resonance, the dipole pygmy resonance, and giant quadrupole modes are excited during the process. The one-body dissipation of collective dipole modes is shown to lead a damping width ???0.4 MeV and the number of preequilibrium neutrons emitted has been quantified.

Stetcu, I.; Bertulani, C. A.; Bulgac, A.; Magierski, P.; Roche, K. J.

2015-01-01

100

Interview with Philip W. Anderson  

SciTech Connect

Phil Anderson, Professor of Physics at Princeton University, has devoted his career to research in theoretical physics. He is a member of the National Academy of Science and the American Academy of Arts and Sciences, a foreign member of the Royal Society, and a foreign associate of the Accademia Lincei in Rome. The Americal Physical Society awarded him the Oliver E. Buckley Solid State Physics Prize in 1964. In 1977 he won the Nobel Prize in Physics with J.H. van Vleck and N.F. Mott. His work has encompassed a broad range of subjects: quantum theory of condensed matter, broken symmetry, transport theory and localization, random statistical systems, spectral line broadening, superfluidity in helium and neutron stars, magnetism, and superconductivity. His avocations include ''hiking, the game of GO, Romanesque architecture, and the human condition.'' In this interview he explains his RVB theory of the oxide superconductors and its historical context.

Anderson, P.W.

1988-08-01

101

General variable separation solution and new localized excitations for the (2+1)-dimensional nonlinear Schrodinger equation  

NASA Astrophysics Data System (ADS)

By applying a special Backlund transformation, a general variable separation Solution for the (2 + 1)-dimensional nonlinear Schrodinger equation is derived. In addition to some types of the usual localized excitations, Such as dromions, lumps, ring solitons, oscillated dromions, and breathers, soliton structures can be easily constructed by selecting arbitrary functions appropriately. A new class of localized excitations, like fractal-dromions, fractal-lumps, peakons, compactors, and folded excitations of this system is found by selecting appropriate functions. Some interesting novel features of these structures are revealed.

Bai, Cheng-Lin; Hu, Hai-Quan; Wang, Wen-Jun; Zhao, Hong

2006-12-01

102

Local electron beam excitation and substrate effect on the plasmonic response of single gold nanostars.  

PubMed

We performed cathodoluminescence (CL) spectroscopy and imaging in a high-resolution scanning electron microscope to locally and selectively excite and investigate the plasmonic properties of a multi-branched gold nanostar on a silicon substrate. This method allows us to map the local density of optical states from the nanostar with a spatial resolution down to a few nanometers. We resolve, both in the spatial and spectral domain, different plasmon modes associated with the nanostar. Finite-difference time-domain (FDTD) numerical simulations are performed to support the experimental observations. We investigate the effect of the substrate on the plasmonic properties of these complex-shaped nanostars. The powerful CL-FDTD combination helps us to understand the effect of the substrate on the plasmonic response of branched nanoparticles. PMID:24029251

Das, Pabitra; Kedia, Abhitosh; Kumar, Pandian Senthil; Large, Nicolas; Chini, Tapas Kumar

2013-10-11

103

Acoustically Coupled Droplet Combustion and Local Extinction under High Amplitude Excitation  

NASA Astrophysics Data System (ADS)

The present experimental study examined the characteristics of liquid ethanol fuel droplet combustion in the presence of high amplitude acoustic excitation, with focus on conditions where high local flame strain can result in the periodic partial extinction and reignition within the flame front in time. These partial extinction phenomena were observed via phase-locked OH* chemiluminescence imaging and identified by the cycle of sudden, severe drop-off in chemiluminescent intensity near the flame stagnation region followed by reignition at the stagnation flame front at a later portion of the acoustic cycle. For increased excitation levels, the burning rate constant values were higher than those for both baseline quiescent and moderate excitation conditions. The experimental acoustic acceleration values were also higher than those for moderate excitation levels. Furthermore, as observed in past studies, these measurements of acoustic acceleration agreed only qualitatively with predictions from the acoustic radiation force theory. The presence of periodic partial extinction did not alter these expected trends. The temporal response in flame luminosity to flow perturbations was also analyzed using the Rayleigh index to determine the degree of thermoacoustic coupling inherent in a burning droplet system for given forcing conditions. When partial extinction was absent, the integrated OH* chemiluminescent intensity oscillated nearly in phase with the pressure perturbation. This led to a positive Rayleigh index, indicating unstable combustion, as was observed in previous studies at moderate excitation. However, partial extinction phenomena altered the relationship between measured intensity and pressure perturbations: the intensity oscillated nearly out of phase with the pressure perturbation. This led to a negative Rayleigh index, indicating stable combustion despite clear evidence of thermoacoustic coupling in the combustion footage and in the combustion property trends. These results indicated that the characterization of thermoacoustic coupling is important to the description of any droplet combustion system undergoing acoustic excitation; however, they also suggested that the Rayleigh index, at least when quantified using OH* chemiluminescence, may not fully capture the nature of thermoacoustic coupling in regimes where partial extinction phenomena occur.

Tran, Phuoc Hai Nguyen

104

PHYSICAL REVIEW A 81, 043801 (2010) Local-field excitations in two-dimensional lattices of resonant atoms  

E-print Network

on any given atom in a medium--the local field (LF)--differs from the macroscopic field EPHYSICAL REVIEW A 81, 043801 (2010) Local-field excitations in two-dimensional lattices of resonant atoms S. N. Volkov and A. E. Kaplan Department of Electrical and Computer Engineering, Johns Hopkins

Kaplan, Alexander

105

Calculation of mean excitation energy and stopping cross section in the orbital local plasma approximation  

NASA Astrophysics Data System (ADS)

Extension of the kinetic theory of stopping, in the Oddershede-Sabin (OS) [At. Data Nucl. Data Tables 31, 275 (1984)] orbitally decomposed form, from gas phase to films and crystals generates the need for orbital mean excitation energies calculated within the local-spin-density approximation (LSDA) to density-functional theory (DFT), the preeminent theoretical model for such extended systems. In LSDA, the orbitals and orbital energies used in the construction of the electron density ? have no standing for estimation or calculation of excitation energies. As an alternative we propose an orbital density generalization of the local plasma approximation (LPA) of Lindhard and Scharff [K. Dan. Vidensk. Selsk. Mat. Fys. Medd. 27, No. 15 (1953)] that we test by calculation of mean excitation energies Ik for each atomic orbital k within the LSDA for all atoms with Z<37. Stopping cross sections for a representative sample (about half) of these elements have been calculated using these Ik values. The results do not differ substantially from those of OS (who used Ik values from Dehmer, Inokuti, and Saxon [Phys. Rev. A 12, 102 (1975)]; Inokuti, Baer, and Dehmer [ibid. 17, 1229 (1978)]; Inokuti, Dehmer, Baer, and Hanson [ibid. 23, 95 (1981)]), with the discrepancy generally less than 15%. Comparison of the LPA and OS orbital mean excitation energies exhibits a number of striking systematic features, including (1) the orbital Ik's corresponding to the orbital lying highest in energy generally differ by less than 40% between the two calculations; (2) the difference at lower energies can be as much as a factor of 3; (3) the ratio IOS/ILPAkk shows, within columns of the Periodic Table, a monotonically decreasing variation as a function of Z for the highest-energy orbital but a smooth variation as a function of Z for the lower-energy orbitals. There seem to be characteristic patterns for each different orbital. Although the two methods give very different Ik's for core orbitals, there is little effect on the resulting stopping cross sections because the valence orbital Ik dominates the stopping for low projectile energies, the energy range of interest here. We give a brief analysis of the sensitivity of the stopping to shifts in Ik values.

Meltzer, David E.; Sabin, John R.; Trickey, S. B.

1990-01-01

106

How Local Excitation–Inhibition Ratio Impacts the Whole Brain Dynamics  

PubMed Central

The spontaneous activity of the brain shows different features at different scales. On one hand, neuroimaging studies show that long-range correlations are highly structured in spatiotemporal patterns, known as resting-state networks, on the other hand, neurophysiological reports show that short-range correlations between neighboring neurons are low, despite a large amount of shared presynaptic inputs. Different dynamical mechanisms of local decorrelation have been proposed, among which is feedback inhibition. Here, we investigated the effect of locally regulating the feedback inhibition on the global dynamics of a large-scale brain model, in which the long-range connections are given by diffusion imaging data of human subjects. We used simulations and analytical methods to show that locally constraining the feedback inhibition to compensate for the excess of long-range excitatory connectivity, to preserve the asynchronous state, crucially changes the characteristics of the emergent resting and evoked activity. First, it significantly improves the model's prediction of the empirical human functional connectivity. Second, relaxing this constraint leads to an unrealistic network evoked activity, with systematic coactivation of cortical areas which are components of the default-mode network, whereas regulation of feedback inhibition prevents this. Finally, information theoretic analysis shows that regulation of the local feedback inhibition increases both the entropy and the Fisher information of the network evoked responses. Hence, it enhances the information capacity and the discrimination accuracy of the global network. In conclusion, the local excitation–inhibition ratio impacts the structure of the spontaneous activity and the information transmission at the large-scale brain level. PMID:24899711

Deco, Gustavo; Hagmann, Patric; Romani, Gian Luca; Mantini, Dante; Corbetta, Maurizio

2014-01-01

107

Natural triple excitations in local coupled cluster calculations with pair natural orbitals  

NASA Astrophysics Data System (ADS)

In this work, the extension of the previously developed domain based local pair-natural orbital (DLPNO) based singles- and doubles coupled cluster (DLPNO-CCSD) method to perturbatively include connected triple excitations is reported. The development is based on the concept of triples-natural orbitals that span the joint space of the three pair natural orbital (PNO) spaces of the three electron pairs that are involved in the calculation of a given triple-excitation contribution. The truncation error is very smooth and can be significantly reduced through extrapolation to the zero threshold. However, the extrapolation procedure does not improve relative energies. The overall computational effort of the method is asymptotically linear with the system size O(N). Actual linear scaling has been confirmed in test calculations on alkane chains. The accuracy of the DLPNO-CCSD(T) approximation relative to semicanonical CCSD(T0) is comparable to the previously developed DLPNO-CCSD method relative to canonical CCSD. Relative energies are predicted with an average error of approximately 0.5 kcal/mol for a challenging test set of medium sized organic molecules. The triples correction typically adds 30%-50% to the overall computation time. Thus, very large systems can be treated on the basis of the current implementation. In addition to the linear C150H302 (452 atoms, >8800 basis functions) we demonstrate the first CCSD(T) level calculation on an entire protein, Crambin with 644 atoms, and more than 6400 basis functions.

Riplinger, Christoph; Sandhoefer, Barbara; Hansen, Andreas; Neese, Frank

2013-10-01

108

Localized Excitation in the Hybridization Gap in YbAl{sub 3}  

SciTech Connect

The intermediate valence compound YbAl{sub 3} exhibits a broad magnetic excitation in the inelastic neutron scattering spectrum with characteristic energy E{sub 1}{approx_equal}50 meV, equal to the Kondo energy (T{sub K}{approx}600-700 K). In the low temperature (Tlocalized excitation in the hybridization gap.

Christianson, A.D.; Fanelli, V.R. [University of California, Irvine, California 92697 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Lawrence, J.M. [University of California, Irvine, California 92697 (United States); Goremychkin, E.A. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); Osborn, R. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Bauer, E.D.; Sarrao, J.L.; Thompson, J.D. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Frost, C.D. [ISIS Facility, Rutherford Appleton Laboratory, Chilton, Didcot OX11 0QX (United Kingdom); Zarestky, J. L. [Ames Laboratory, Iowa State University, Ames, Iowa 50011 (United States)

2006-03-24

109

Fluorescence imaging of local membrane electric fields during the excitation of single neurons in culture.  

PubMed Central

The spatial distribution of depolarized patches of membrane during the excitation of single neurons in culture has been recorded with a high spatial resolution (1 micron2/pixel) imaging system based on a liquid-nitrogen-cooled astronomical camera mounted on an inverted microscope. Images were captured from rat nodose neurons stained with the voltage-sensitive dye RH237. Conventional intracellular microelectrode recordings were made in synchrony with the images. During an action potential the fluorescence changes occurred in localized, unevenly distributed membrane areas, which formed clusters of depolarized sites of different sizes and intensities. When fast conductances were blocked by the addition of tetrodotoxin, a reduction in the number and the intensities of the depolarized sites was observed. The blockade by tetrodotoxin of voltage-clamped neurons also reduced the number of depolarized sites, although the same depolarizing voltage step was applied. Similarly, when a voltage-clamped neuron was depolarized by a constant-amplitude voltage step, the number of depolarized sites varied according to the degree of activation of the voltage-sensitive channels, which was modified by changing the holding potential. These results suggest that the spatial patterns of depolarization observed during excitation are related to the operations of ionic channels in the membrane. Images FIGURE 1 FIGURE 2 FIGURE 4 FIGURE 5 FIGURE 6 FIGURE 7 PMID:8527643

Gogan, P; Schmiedel-Jakob, I; Chitti, Y; Tyc-Dumont, S

1995-01-01

110

Locally-Excited (LE) versus Charge-Transfer (CT) Excited State Competition in a Series of Para-Substituted Neutral Green Fluorescent Protein (GFP) Chromophore Models.  

PubMed

In this paper, I provide a characterization of the low-energy electronic structure of a series of para-substituted neutral green fluorescent protein (GFP) chromophore models using a theoretical approach that blends linear free energy relationships (LFERs) with state-averaged complete-active-space self-consistent field (SA-CASSCF) theory. The substituents are chosen to sample the Hammett ?p scale from R = F to NH2, and a model of the neutral GFP chromophore structure (R = OH) is included. I analyze the electronic structure for different members of the series in a common complete-active-space valence-bond (CASVB) representation, exploiting an isolobal analogy between active-space orbitals for different members of the series. I find that the electronic structure of the lowest adiabatic excited state is a strong mixture of weakly coupled states with charge-transfer (CT) or locally excited (LE) character and that the dominant character changes as the series is traversed. Chromophores with strongly electron-donating substituents have a CT-like excited state such as expected for a push-pull polyene or asymmetric cyanine. Chromophores with weakly electron-donating (or electron-withdrawing) substituents have an LE-like excited state with an ionic biradicaloid structure localized to the ground-state bridge ? bond. PMID:25343562

Olsen, Seth

2015-02-12

111

Head-on collisions of localized pressure excitations in derivative cubic relaxing media: dynamical structure survey  

NASA Astrophysics Data System (ADS)

In the wake of the recent derivation of the new cubic nonlinear evolution equation of high-frequency pressure perturbations of a barothropic medium under relaxation (Kuetche V K et al 2014 J. Math. Phys. 55 052702), we closely investigate the head-on collisions of some typical localized waveguide excitations, which are solutions to the previous system. From the viewpoint of Hirota?s formalism, we delve into the structural scattering features of the interacting waves mentioned above. As a result, we find that there might exist some ‘characteristic’ amplitude ratio of the interacting waves at which the scattering changes its features. Accordingly, we provide an illustration of the previous result within the depiction of the interactions between three single soliton solutions alongside the phase-shift of each particle. Following these depictions, we address some physical implications of the results as well as the different potential applications.

Youssoufa, Saliou; Kamgang Kuetche, Victor; Crepin Kofane, Timoleon

2015-02-01

112

Local resonant excitation of plasma oscillations in a planar surface-wave plasma device  

NASA Astrophysics Data System (ADS)

The paper presents space-resolved microwave intensity measurements in a surface-wave plasma device clearly demonstrating the existence of a local resonance in a resonance layer where the local electron plasma frequency is equal to the surface-wave frequency. It has already been suggested in the literature that Landau damping of electron plasma waves excited in such a resonance layer and/or stochastic electron heating there might contribute to the surface-wave plasma energy balance. Since this does not involve collisions, it may become an important energy channel at low gas pressures. In order to avoid having the resonance layer too close to the plasma boundary, the measurements were performed not in the original surface-wave plasma, but using a weak non-ionizing 2.4 GHz microwave propagating in an inductively coupled plasma created by an internal loop antenna fed by a high-power 13.56 MHz generator. Still the original surface-wave plasma source geometry, including the microwave input port, was preserved. The resonance layer was identified by the microwave intensity peak, which was found to shift on changing the plasma density profile and/or the wave driving frequency in compliance with theoretical expectations. Accompanying space-resolved plasma density measurements confirmed this interpretation.

Ghanashev, I.; Sugai, H.; Morita, S.; Toyoda, N.

1999-08-01

113

Plasmon Excitations in Scanning Tunneling Microscopy: Simultaneous Imaging of Modes with Different Localizations Coupled at the Tip  

SciTech Connect

The authors investigate the localization of photons emitted at the tip during scanning tunneling microscopy measurements on atomically flat gold substrates. Emission patterns of the plasmon-mediated luminescence exhibit distinct features that are assigned to the localized modes of the surface plasmon (LSP) confined to the tunneling gap and propagating modes (PSP) coupled to the LSP by the optical cavity beneath the tip. Tunneling luminescence spectroscopy reveals that the plasmon localization at the tip increases when modes of higher energy are excited. Acquisition of local emission patterns allows us for the simultaneous imaging of LSP and PSP modes.

Romero, M. J.; van de Lagemaat, J.; Rumbles, G.; Al-Jassim, M. M.

2007-01-01

114

How Large is Large? Estimating the Critical Disorder for the Anderson Model  

NASA Astrophysics Data System (ADS)

Complete localization is shown to hold for the d-dimensional Anderson model with uniformly distributed random potentials provided the disorder strength where satisfies with the self-avoiding walk connective constant for the lattice . Notably, is precisely the large disorder threshold proposed by Anderson in 1958.

Schenker, Jeffrey

2015-01-01

115

Transition from Charge-Transfer to Largely Locally Excited Exciplexes, from Structureless to Vibrationally Structured Emissions.  

PubMed

Exciplexes of 9,10-dicyanoanthracene (DCA) with alkylbenzene donors in cyclohexane show structureless emission spectra, typical of exciplexes with predominantly charge-transfer (CT) character, when the donor has a relatively low oxidation potential (Eox ), e.g. hexamethylbenzene (HMB). With increasing Eox and stronger mixing with a locally excited (LE) state, vibrational structure begins to appear with 1,2,3,5-tetramethylbenzene and becomes prominent with p-xylene (p-Xy). A simple theoretical model reproduces the spectra and the radiative rate constants, and it reveals several surprises: Even in this nonpolar solvent, the fractional CT character of a highly mixed exciplex varies widely in response to fluctuations in the microscopic environment. Environments that favor the LE (or CT) state contribute more to the blue (or red) side of the overall spectrum. It is known that sparsely substituted benzene radical cations, e.g., p-Xy(•+) , are stabilized more in acetonitrile than the heavily substituted HMB(•+) . Remarkably, ion pairing with DCA(•-) in cyclohexane leads to even larger differences in the stabilization of these radical cations. The spectra of the low-Eox donors are almost identical except for displacements that approximately equal the differences in Eox , even though the exciplexes have varying degrees of CT character. These similarities result from compensation among several nonobvious, but quantified factors. PMID:25363042

Young, Ralph H; Feinberg, Adam M; Dinnocenzo, Joseph P; Farid, Samir

2014-11-01

116

Spin-dependent localized Hartree-Fock density-functional approach for the accurate treatment of inner-shell excitation of closed-shell atoms  

E-print Network

-shell excited states of closed-shell atoms by means of a spin- dependent localized Hartree-Fock SLHF densitySpin-dependent localized Hartree-Fock density-functional approach for the accurate treatment of inner-shell excitation of closed-shell atoms Zhongyuan Zhou1,2 and Shih-I Chu1 1 Department of Chemistry

Chu, Shih-I

117

Ultrahigh-field MRI whole-slice and localized RF field excitations using the same RF transmit array.  

PubMed

In this paper, a multiport driving mechanism is numerically implemented at ultra high-field (UHF) magnetic resonance imaging (MRI) to provide 1) homogenous whole-slice (axial, sagittal, or coronal) and 2) highly localized radio frequency (RF) field excitation within the same slices, all with the same RF transmit array (here chosen to be a standard transverse electromagnetic (TEM) resonator/coil). The method is numerically tested using a full-wave model of a TEM coil loaded with a high-resolution/18-tissue/anatomically detailed human head mesh. The proposed approach is solely based on electromagnetic and phased array antenna theories. The results demonstrate that both homogenous whole-slice as well as localized RF excitation can be achieved within any slice of the head at 7 T (298 MHz for proton imaging). PMID:17024837

Ibrahim, Tamer S

2006-10-01

118

The effects of an excited impinging jet on the local heat transfer coefficient of aircraft turbine blades  

NASA Astrophysics Data System (ADS)

The primary objective of this paper is to present the results of research into the effects of periodic excitation upon the local heat transfer characteristics of a turbine blade cooled by an impinging jet of air. A curved plate (used to simulate the inner leading edge of a turbine blade) was subjected to a two-dimensional jet flow field (Re = 10,000) with a superimposed periodic acoustic disturbance. When compared to the naturally disturbed flow, the excited flow field was found to reduce the local Nusselt number and cool the blade less efficiently (by as much as ten percent in the extreme cases). The results of the study appear to indicate that harmonic disturbances present a serious controlling factor in the quest for optimization of turbine blade cooling techniques. By isolating dominant frequencies in gas turbine engines and working to suppress them, it is believed that significant contributions towards the desired increase in turbine inlet temperature could be possible.

Disimile, P. J.; Paule, D. M.

1988-06-01

119

Nonlocal and local magnetization dynamics excited by an RF magnetic field in magnetic multilayers  

NASA Astrophysics Data System (ADS)

A microwave study in spintronic devices has been actively pursued in the past several years due to the fertile physics and potential applications. On one hand, a passive use of microwave can be very helpful to analyze and understand the magnetization dynamics in spintronic devices. Examples include ferromagnetic resonance (FMR) measurements, and various microwave spectrum analyses in ferromagnetic materials. The most important chrematistic parameter for the phenomenological analysis on the magnetization dynamics is, so called, the Gilbert damping constant. In this work, a relatively new measurement technique, a flip-chip FMR measurement, to conduct the ferromagnetic resonance measurements has been developed. The measurement technique is equally comparable to a conventional FMR measurement. The Gilbert damping constants were extracted for single ferromagnetic layer, spin vale structures, and magnetic tunnel junctions (MTJs). On the other hand, an active use of microwave yields a great potential for interesting phenomena which give new functionalities into spintronic devices. For instance, a spin wave excitation by an rf field can be used to reduce the switching field of a ferromagnet, i.e. microwave assisted magnetization reversal, which could be a potential application in advanced recording media. More interestingly, a precessing magnetization driven by an rf field can generate a pure spin current into a neighboring layer, i.e. spin pumping effect, which is one of the candidates for generating a pure spin current. A ferromagnetic tunnel junction (MTJ) is one of the important devices in spintronics, which is also the key device to investigate the local and nonlocal magnetization dynamics in this work. Therefore, it is also important to develop high quality MTJs. My work starts from the development of MTJ with AlOx and MgO tunnel barriers where it was found it is crucial to find the proper condition for forming a few nanometers thick tunnel barrier. After obtaining quality MTJs, we proceeded to the study on magnetization dynamics using the MTJs. First interesting phenomenon found in this work is the microwave assisted magnetization reversal (MAMR). It is found that magnetization reversal can be achieved efficiently by an appropriate power and frequency microwave. Moreover, there is a mutual relationship between microwave power and frequency for achieving a maximum switching field reduction. This effect can be very useful in magnetic data storage device which essentially needs to reduce the "effective" coercivity field. In the study of nonlocal magnetization dynamics, we tried to detect the spin accumulation induced by spin pumping effect in FM/NM/I/FM, FM/I/NM and FM/I/FM structures with a microwave excitation (FM: ferromagnetic material, NM: nonmagnetic material, and I: tunnel barrier). Interestingly, in the FM/I/NM and FM/I/FM structures, we observed ˜muV dc voltage due to the precessing magnetizations. It is found that the dc voltage we observed is much larger than the current the spin pumping theory predicts. Therefore we speculated a new mechanism to explain the results. Although we discussed only a portion of the magnetization dynamics involving nonlinear and nonequilibrium phenomena, it reveals that there is still a fertile physics which has not yet been investigated or explained.

Moriyama, Takahiro

120

Value of epicardial potential maps in localizing pre-excitation sites for radiofrequency ablation. A simulation study  

NASA Astrophysics Data System (ADS)

Using computer simulations, we systematically investigated the limitations of an inverse solution that employs the potential distribution on the epicardial surface as an equivalent source model in localizing pre-excitation sites in Wolff-Parkinson-White syndrome. A model of the human ventricular myocardium that features an anatomically accurate geometry, an intramural rotating anisotropy and a computational implementation of the excitation process based on electrotonic interactions among cells, was used to simulate body surface potential maps (BSPMs) for 35 pre-excitation sites positioned along the atrioventricular ring. Two individualized torso models were used to account for variations in torso boundaries. Epicardial potential maps (EPMs) were computed using the L-curve inverse solution. The measure for accuracy of the localization was the distance between a position of the minimum in the inverse EPMs and the actual site of pre-excitation in the ventricular model. When the volume conductor properties and lead positions of the torso were precisely known and the measurement noise was added to the simulated BSPMs, the minimum in the inverse EPMs was at 12 ms after the onset on average within cm of the pre-excitation site. When the standard torso model was used to localize the sites of onset of the pre-excitation sequence initiated in individualized male and female torso models, the mean distance between the minimum and the pre-excitation site was cm for the male torso and cm for the female torso. The findings of our study indicate that a location of the minimum in EPMs computed using the inverse solution can offer non-invasive means for pre-interventional planning of the ablative treatment.

Hren, Rok

1998-06-01

121

Conservation genetics of a rare Gerbil species: a comparison of the population genetic structures and demographic histories of the locally rare Pygmy Gerbil and the common Anderson's Gerbil  

PubMed Central

Background One of the major challenges in evolutionary biology is identifying rare species and devising management plans to protect them while also sustaining their genetic diversity. However, in attempting a broad understanding of rarity, single-species studies provide limited insights because they do not reveal whether the factors that affect rare species differ from those that affect more common species. To illustrate this important concept and to arrive at a better understanding of the form of rarity characterizing the rare Gerbillus henleyi, we explored its population genetic structure alongside that of the locally common Gerbillus andersoni allenbyi. We trapped gerbils in several locations in Israel's western and inner Negev sand dunes. We then extracted DNA from ear samples, and amplified two mitochondrial sequences: the control region (CR) and the cytochrome oxidase 2 gene (CO2). Results Nucleotide diversity was low for all sequences, especially for the CR of G. a. allenbyi, which showed no diversity. We could not detect any significant population genetic structure in G. henleyi. In contrast, G. a. allenbyi's CO2 sequence showed significant population genetic structure. Pairwise PhiPT comparisons showed low values for G. henleyi but high values for G. a. allenbyi. Analysis of the species' demographic history indicated that G. henleyi's population size has not changed recently, and is under the influence of an ongoing bottleneck. The same analysis for G. a. allenbyi showed that this species has undergone a recent population expansion. Conclusions Comparing the two species, the populations of G. a. allenbyi are more isolated from each other, likely due to the high habitat specificity characterizing this species. The bottleneck pattern found in G. henleyi may be the result of competition with larger gerbil species. This result, together with the broad habitat use and high turnover rate characterizing G. henleyi, may explain the low level of differentiation among its populations. The evidence for a recent population expansion of G. a. allenbyi fits well with known geomorphological data about the formation of the Negev sand dunes and paleontological data about this species' expansion throughout the Levant. In conclusion, we suggest that adopting a comparative approach as presented here can markedly improve our understanding of the causes and effects of rarity, which in turn can allow us to better protect biodiversity patterns. PMID:20525191

2010-01-01

122

The Anderson Quin Cycle. Final report  

Microsoft Academic Search

The objective of this study was to make a more refined evaluation of the Anderson Quin Cycle based on most recent information on the performance of various elements that will be used in the Anderson Quin Cycle. My original estimate of the work plan for evaluating and optimizing the Anderson Quin Cycle called for 7000 man hours of work. Since

J. H. Anderson; W. M. Bilbow

1993-01-01

123

Describing excited state relaxation and localization in TiO2 nanoparticles using TD-DFT  

SciTech Connect

We have investigated the description of excited state relaxation in naked and hydrated TiO2 nanoparticles using Time-Dependent Density Functional Theory (TD-DFT) with three common hybrid exchange-correlation (XC) potentials; B3LYP, CAM-B3LYP and BHLYP. Use of TD-CAM-B3LYP and TD-BHLYP yields qualitatively similar results for all structures, which are also consistent with predictions of coupled cluster theory for small particles. TD-B3LYP, in contrast, is found to make rather different predictions; including apparent conical intersections for certain particles that are not observed with TD-CAM-B3LYP nor with TD-BHLYP. In line with our previous observations for vertical excitations, the issue with TD-B3LYP appears to be the inherent tendency of TD-B3LYP, and other XC potentials with no or a low percentage of Hartree-Fock Like Exchange, to spuriously stabilize the energy of charge-transfer (CT) states. Even in the case of hydrated particles, for which vertical excitations are generally well described with all XC potentials, the use of TD-B3LYP appears to result in CT-problems for certain particles. We hypothesize that the spurious stabilization of CT-states by TD-B3LYP even may drive the excited state optimizations to different excited state geometries than those obtained using TD-CAM-B3LYP or TD-BHLYP. Finally, focusing on the TD-CAM-B3LYP and TD-BHLYP results, excited state relaxation in naked and hydrated TiO2 nanoparticles is predicted to be associated with a large Stokes’ shift.

Berardo, Enrico; Hu, Hanshi; van Dam, Hubertus JJ; Shevlin, S. A.; Woodley, Scott M.; Kowalski, Karol; Zwijnenburg, Martijn A.

2014-10-30

124

Excitation of dark plasmons in metal nanoparticles by a localized emitter.  

SciTech Connect

We study theoretically a dipole emitter placed near a metal nanoparticle and near small chains of two and three nanoparticles. The emitter can efficiently excite dark, or nonradiative, surface-plasmon modes in the nanostructures, in addition to the well-known bright modes. In the case of coupled nanoparticles, the origins of the bright and dark modes can be understood in the context of plasmon hybridization. Excitation of dark modes in nanoparticle chains allows for subwavelength guiding of optical energy with no radiative losses and thus with improved propagation lengths.

Liu, M.; Lee, T.-W.; Gray, S.; Guyot-Sionnest, P.; Pelton, M.; Univ. of Chicago

2009-03-13

125

JESSICA ANDERSON MAISANO February 2008  

E-print Network

JESSICA ANDERSON MAISANO February 2008 Current Position Research Engineer/Scientist Associate III, High-Resolution X-ray Computed Tomography Facility, Jackson School of Geosciences, The University@mail.utexas.edu Previous Positions 2004-2005 Research Associate, High-Resolution X-ray Computed Tomography Facility

Yang, Zong-Liang

126

Local CC2 response method based on the Laplace transform: analytic energy gradients for ground and excited states.  

PubMed

A multistate local CC2 response method for the calculation of analytic energy gradients with respect to nuclear displacements is presented for ground and electronically excited states. The gradient enables the search for equilibrium geometries of extended molecular systems. Laplace transform is used to partition the eigenvalue problem in order to obtain an effective singles eigenvalue problem and adaptive, state-specific local approximations. This leads to an approximation in the energy Lagrangian, which however is shown (by comparison with the corresponding gradient method without Laplace transform) to be of no concern for geometry optimizations. The accuracy of the local approximation is tested and the efficiency of the new code is demonstrated by application calculations devoted to a photocatalytic decarboxylation process of present interest. PMID:24784259

Ledermüller, Katrin; Schütz, Martin

2014-04-28

127

Local CC2 response method based on the Laplace transform: Analytic energy gradients for ground and excited states  

SciTech Connect

A multistate local CC2 response method for the calculation of analytic energy gradients with respect to nuclear displacements is presented for ground and electronically excited states. The gradient enables the search for equilibrium geometries of extended molecular systems. Laplace transform is used to partition the eigenvalue problem in order to obtain an effective singles eigenvalue problem and adaptive, state-specific local approximations. This leads to an approximation in the energy Lagrangian, which however is shown (by comparison with the corresponding gradient method without Laplace transform) to be of no concern for geometry optimizations. The accuracy of the local approximation is tested and the efficiency of the new code is demonstrated by application calculations devoted to a photocatalytic decarboxylation process of present interest.

Ledermüller, Katrin; Schütz, Martin, E-mail: martin.schuetz@chemie.uni-regensburg.de [Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg (Germany)] [Institute of Physical and Theoretical Chemistry, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg (Germany)

2014-04-28

128

Fragility, Stokes-Einstein violation, and correlated local excitations in a coarse-grained model of an ionic liquid  

E-print Network

Dynamics of a coarse-grained model for the room-temperature ionic liquid, 1-ethyl-3-methylimidazolium hexafluorophosphate, couched in the united-atom site representation are studied via molecular dynamics simulations. The dynamically heterogeneous behavior of the model resembles that of fragile supercooled liquids. At or close to room temperature, the model ionic liquid exhibits slow dynamics, characterized by nonexponential structural relaxation and subdiffusive behavior. The structural relaxation time, closely related to the viscosity, shows a super-Arrhenius behavior. Local excitations, defined as displacement of an ion exceeding a threshold distance, are found to be mainly responsible for structural relaxation in the alternating structure of cations and anions. As the temperature is lowered, excitations become progressively more correlated. This results in the decoupling of exchange and persistence times, reflecting a violation of the Stokes-Einstein relation.

Daun Jeong; M. Y. Choi; Hyung. J. Kim; YounJoon Jung

2010-02-03

129

Fragility, Stokes-Einstein violation, and correlated local excitations in a coarse-grained model of an ionic liquid  

E-print Network

Dynamics of a coarse-grained model for the room-temperature ionic liquid, 1-ethyl-3-methylimidazolium hexafluorophosphate, couched in the united-atom site representation are studied via molecular dynamics simulations. The dynamically heterogeneous behavior of the model resembles that of fragile supercooled liquids. At or close to room temperature, the model ionic liquid exhibits slow dynamics, characterized by nonexponential structural relaxation and subdiffusive behavior. The structural relaxation time, closely related to the viscosity, shows a super-Arrhenius behavior. Local excitations, defined as displacement of an ion exceeding a threshold distance, are found to be mainly responsible for structural relaxation in the alternating structure of cations and anions. As the temperature is lowered, excitations become progressively more correlated. This results in the decoupling of exchange and persistence times, reflecting a violation of the Stokes-Einstein relation.

Jeong, Daun; Kim, Hyung J; Jung, YounJoon; 10.1039/B921725H

2010-01-01

130

Localization of Spinons in Random Majumdar-Ghosh Chains  

NASA Astrophysics Data System (ADS)

We study the effect of disorder on frustrated dimerized spin-1/2 chains at the Majumdar-Ghosh point. Using variational methods and density-matrix renormalization group approaches, we identify two localization mechanisms for spinons which are the deconfined fractional elementary excitations of these chains. The first one belongs to the Anderson localization class and dominates at the random Majumdar-Ghosh point. There, spinons remain gapped and localize in Lifshitz states whose localization length is analytically obtained. The other mechanism is a random confinement mechanism which induces an effective interaction between spinons and brings the chain into a gapless and partially polarized phase for arbitrarily small disorder.

Lavarélo, Arthur; Roux, Guillaume

2013-02-01

131

Spin wave dynamics and the determination of intrinsic damping in locally excited Permalloy thin films.  

PubMed

Time-resolved scanning Kerr effect microscopy has been used to study magnetization dynamics in Permalloy thin films excited by transient magnetic pulses generated by a micrometer-scale transmission line structure. The results are consistent with magnetostatic spin wave theory and are supported by micromagnetic simulations. Magnetostatic volume and surface spin waves are measured for the same specimen using different bias field orientations and can be accurately calculated by k-space integrations over all excited plane wave components. A single damping constant of Gilbert form is sufficient to describe both scenarios. The nonuniform pulsed field plays a key role in the spin wave dynamics, with its Fourier transform serving as a weighting function for the participating modes. The intrinsic Gilbert damping parameter alpha is most conveniently measured when the spin waves are effectively stationary. PMID:17359122

Liu, Zhigang; Giesen, Fabian; Zhu, Xiaobin; Sydora, Richard D; Freeman, Mark R

2007-02-23

132

Local conformations and excited state dynamics of porphyrins and nucleic acids by 2-dimensional fluorescence spectroscopy  

NASA Astrophysics Data System (ADS)

Biological systems present many challenges to researchers attempting to study them using spectroscopy. Low specificity, low sensitivity, and broad and overlapping lineshapes limit the amount of information that can be obtained in experiments. Two-dimensional fluorescence spectroscopy (2D FS) is a highly sensitive and information-rich spectroscopic technique that was developed to study the conformations and excited state dynamics of systems exhibiting exciton coupling. In this dissertation, I describe a variety of extensions of 2D FS that further increase its utility for the study of biological systems. I describe experiments on a dimer of zinc tetraphenylporphyrin embedded in a membrane, in which the signals from two conformational subpopulations were separated in order to study the thermodynamics of their interconversion. I present proof-of-principle experiments on nucleic acids that utilize fluorescence resonance energy transfer to separate signals from different subpopulations. I also describe experiments in which 2D FS was performed using ultraviolet excitation to determine the conformation of a dinucleotide of a fluorescent analogue of the nucleic acid base adenine. I discuss experiments on porphyrin dimers in which 2D FS was used as a probe of excited state dynamics. Finally, I present model calculations for a proposed variation of 2D FS in which entangled photons would be used as the excitation source. These calculations suggest that this approach has the potential to yield significantly narrower spectral lineshapes than conventional 2D FS. These experiments and calculations yield new insight into the systems investigated and establish a `toolbox' of variations of 2D FS that can be used to gain as much information as possible from experiments on challenging systems such as protein-DNA complexes.

Widom, Julia R.

133

Solvent Effects on the Optical Spectra and Excited-State Decay of Triphenylamine-thiadiazole with Hybridized Local Excitation and Intramolecular Charge Transfer.  

PubMed

The triphenylamine-thiadiazole molecule (TPA-NZP) is a newly popular, highly efficient OLED fluorescent emitter with exciton utilization efficiency exceeding the upper limit of spin statistics (25%). In this work, the optical spectra and the radiative and nonradiative decay rate constants have been investigated theoretically for TPA-NZP in hexane, ethyl ether, tetrahydrofuran, and dimethylformamide solvents, in comparison with the gas phase. We observed the evolutions of the excited states from the hybridized local and charge-transfer (HLCT) character to complete intramolecular charge transfer (CT) character with the increase of the solvent polarities. It is found that upon increasing the solvent polarity, the amount of red shift in the absorption peak is much less than that of emission, resulting in breakdown of the mirror symmetry. This is because that 0-0 transition energy is red-shifted but the vibrational relaxation increases with the solvent polarity, leading to subtraction in absorption while addition in emission. The radiative decay rate constant is calculated to be almost independent of polarity. The nonradiative decay rate increases by almost one order of magnitude from that in nonpolar hexane to the strongly polarized dimethylformamide, which is attributed to the dual effects of the red shift in the gap and enhancement of the vibrational relaxation by solvent polarity. PMID:25402947

Fan, Di; Yi, Yuanping; Li, Zhendong; Liu, Wenjian; Peng, Qian; Shuai, Zhigang

2014-11-25

134

America's First Illustrator: Alexander Anderson  

NSDL National Science Digital Library

America has produced many notable wood engravers, but Alexander Anderson is one of the first to have name recognition. Born in 1775, he spent his lifetime crafting illustrations for books, periodicals, newspapers, and other commercial ephemera. This delightful digital collection from the New York Public Library brings together sixteen scrapbooks containing almost 10,000 wood engravings by Anderson. Visitors can click on the "Browse Source Titles" area to view the various volumes, and the subjects covered here are quite diverse. Even a cursory search returns dozens of cat engravings, illustrations of slaves, and lottery advertisements. For anyone with an interest in 19th century material culture, this collection is truly wonderful. It is worth making several return trips to get a full sense of the offerings here, and it is one that will bring new rewards upon each visit.

135

Atomic mean excitation energies for stopping powers from local plasma oscillator strengths  

NASA Technical Reports Server (NTRS)

The stopping of a charged particle by isolated atoms is investigated theoretically using an 'atomic plasma' model in which atomic oscillator strengths are replaced by the plasma frequency spectrum. The plasma-frequency correction factor for individual electron motion proposed by Pines (1953) is incorporated, and atomic mean excitation energies are calculated for atoms through Sr. The results are compared in a graph with those obtained theoretically by Inokuti et al. (1978, 1981) and Dehmer et al. (1975) and with the experimental values compiled by Seltzer and Berger (1982): good agreement is shown.

Wilson, J. W.; Xu, Y. J.; Chang, C. K.; Kamaratos, E.

1984-01-01

136

Excite Travel  

NSDL National Science Digital Library

Excite Travel is one of the most comprehensive international guides to communities around the world. Excite Travel provides easy and timely access to information on travel, entertainment, and local business, plus government and community services for all regions of the world.

137

Local structural changes in excited Ti3+:Al2O3 studied by time-resolved XANES  

NASA Astrophysics Data System (ADS)

Transient changes in the local structure of optically excited Ti3+ ions in a Al2O3 single crystal are studied by time-resolved x-ray absorption spectroscopy. A model considering coupling of the excited E2(C3v) electronic state of the Ti3+ ion to the approximate A1g(Oh) and Eg(Oh) local vibrational modes of the TiO6 octahedron is constructed to fit the experimental data. We determine the magnitude of the A1g(Oh) mode and give an estimate of the Eg(Oh) Jahn-Teller distortion although this analysis does not distinguish between compression and elongation of the oxygen octahedron. Assuming a compressed octahedron, the Eg(Oh) distortion is found to be 0.14±0.02Å with an A1g(Oh) mode of 0.066±0.006Å . In the case of an elongated octahedron the Eg(Oh) distortion is -0.195±0.017Å with an A1g(Oh) mode of 0.052±0.002Å .

Vorobeva, E.; Johnson, S. L.; Beaud, P.; Milne, C. J.; Benfatto, M.; Ingold, G.

2009-10-01

138

Near-unity broadband absorption designs for semiconducting nanowire arrays via localized radial mode excitation.  

PubMed

We report design methods for achieving near-unity broadband light absorption in sparse nanowire arrays, illustrated by results for visible absorption in GaAs nanowires on Si substrates. Sparse (<5% fill fraction) nanowire arrays achieve near unity absorption at wire resonant wavelengths due to coupling into 'leaky' radial waveguide modes of individual wires and wire-wire scattering processes. From a detailed conceptual development of radial mode resonant absorption, we demonstrate two specific geometric design approaches to achieve near unity broadband light absorption in sparse nanowire arrays: (i) introducing multiple wire radii within a small unit cell array to increase the number of resonant wavelengths, yielding a 15% absorption enhancement relative to a uniform nanowire array and (ii) tapering of nanowires to introduce a continuum of diameters and thus resonant wavelengths excited within a single wire, yielding an 18% absorption enhancement over a uniform nanowire array. PMID:24922398

Fountaine, Katherine T; Kendall, Christian G; Atwater, Harry A

2014-05-01

139

Quantum simulation of Anderson and Kondo lattices with superconducting qubits  

E-print Network

We introduce a mapping between a variety of superconducting circuits and a family of Hamiltonians describing localized magnetic impurities interacting with conduction bands. This includes the Anderson model, the single impurity one- and two-channel Kondo problem, as well as the 1D Kondo lattice. We compare the requirements for performing quantum simulations using the proposed circuits to those of universal quantum computation with superconducting qubits, singling out the specific challenges that will have to be addressed.

Juan Jose Garcia-Ripoll; Enrique Solano; Miguel Angel Martin-Delgado

2007-09-11

140

Quantum simulation of Anderson and Kondo lattices with superconducting qubits  

E-print Network

We introduce a mapping between a variety of superconducting circuits and a family of Hamiltonians describing localized magnetic impurities interacting with conduction bands. This includes the Anderson model, the single impurity one- and two-channel Kondo problem, as well as the 1D Kondo lattice. We compare the requirements for performing quantum simulations using the proposed circuits to those of universal quantum computation with superconducting qubits, singling out the specific challenges that will have to be addressed.

Garcia-Ripoll, Juan Jose; Martin-Delgado, Miguel Angel

2007-01-01

141

Direct picosecond time resolution of unimolecular reactions initiated by local mode excitation  

NASA Technical Reports Server (NTRS)

Attention is given to the first results of direct, picosec measurements of the Delta-nu(OH) 5 local mode transition of H2O2. These time-resolved studies yield a direct measure of the unimolecular dissociation rate, and furnish a lower limit for the rate of energy redistribution from the OH stretch to the O-O reaction coordinate. The data thus determined may be used to ascertain the domain of validity for statistical unimolecular reaction rate theories.

Scherer, N. F.; Doany, F. E.; Zewail, A. H.; Perry, J. W.

1986-01-01

142

Conservation laws, radiative decay rates, and excited state localization in organometallic complexes with strong spin-orbit coupling  

E-print Network

There is longstanding fundamental interest in 6-fold coordinated $d^6$ ($t_{2g}^6$) transition metal complexes such as [Ru(bpy)$_3$]$^{2+}$ and Ir(ppy)$_3$, particularly their phosphorescence. This interest has increased with the growing realisation that many of these complexes have potential uses in applications including photovoltaics, imaging, sensing, and light-emitting diodes. In order to design new complexes with properties tailored for specific applications a detailed understanding of the low-energy excited states, particularly the lowest energy triplet state, $T_1$, is required. Here we describe a model of pseudo-octahedral complexes based on a pseudo-angular momentum representation and show that the predictions of this model are in excellent agreement with experiment - even when the deviations from octahedral symmetry are large. This model gives a natural explanation of zero-field splitting of $T_1$ and of the relative radiative rates of the three sublevels in terms of the conservation of time-reversal parity and total angular momentum modulo two. We show that the broad parameter regime consistent with the experimental data implies significant localization of the excited state.

B. J. Powell

2015-01-05

143

CaMKII locally encodes L-type channel activity to signal to nuclear CREB in excitation-transcription coupling.  

PubMed

Communication between cell surface proteins and the nucleus is integral to many cellular adaptations. In the case of ion channels in excitable cells, the dynamics of signaling to the nucleus are particularly important because the natural stimulus, surface membrane depolarization, is rapidly pulsatile. To better understand excitation-transcription coupling we characterized the dependence of cAMP response element-binding protein phosphorylation, a critical step in neuronal plasticity, on the level and duration of membrane depolarization. We find that signaling strength is steeply dependent on depolarization, with sensitivity far greater than hitherto recognized. In contrast, graded blockade of the Ca(2+) channel pore has a remarkably mild effect, although some Ca(2+) entry is absolutely required. Our data indicate that Ca(2+)/CaM-dependent protein kinase II acting near the channel couples local Ca(2+) rises to signal transduction, encoding the frequency of Ca(2+) channel openings rather than integrated Ca(2+) flux-a form of digital logic. PMID:19047462

Wheeler, Damian G; Barrett, Curtis F; Groth, Rachel D; Safa, Parsa; Tsien, Richard W

2008-12-01

144

A rational reduction of CI expansions: combining localized molecular orbitals and selected charge excitations.  

PubMed

Based on localized molecular orbitals, the proposed method reduces large configuration interaction (CI) spaces while maintaining agreement with reference values. Our strategy concentrates the numerical effort on physically pertinent CI-contributions and is to be considered as a tool to tackle large systems including numerous open-shells. To show the efficiency of our method we consider two 4-electron parent systems. First, we illustrate our approach by describing the van der Waals interactions in the (H2)2 system. By systematically including local correlation, dispersion and charge transfer mechanisms, we show that 90% of the reference full CI dissociation energy of the H2 dimer is reproduced using only 3% of the full CI space. Second, the conformational cis/trans rotation barrier of the butadiene molecule is remarkably reproduced (97% of the reference value) with less than 1% of the reference space. This work paves the way to numerical strategies which afford the electronic structure determination of large open-shell systems avoiding the exponential limitation. At the same time, a physical analysis of the contents of the wave function is offered. PMID:24935105

Krah, Tim; Ben Amor, Nadia; Maynau, Daniel; Berger, J A; Robert, Vincent

2014-07-01

145

Timed Common Lisp: Scott D. Anderson  

E-print Network

Timed Common Lisp: Scott D. Anderson Spelman College Atlanta, GA anderson©auc, edu The Duration among AI simu- lators for reai-time planning [1]. Unfortunately, there are problems with using CPU time the increments are determined. 2.1 Low-level Models A "low-level" primitive is a primitive of the Common Lisp

146

Functional renormalization group study of the Anderson-Holstein model  

NASA Astrophysics Data System (ADS)

We present a comprehensive study of the spectral and transport properties in the Anderson-Holstein model both in and out of equilibrium using the functional renormalization group (fRG). We show how the previously established machinery of Matsubara and Keldysh fRG can be extended to include the local phonon mode. Based on the analysis of spectral properties in equilibrium we identify different regimes depending on the strength of the electron-phonon interaction and the frequency of the phonon mode. We supplement these considerations with analytical results from the Kondo model. We also calculate the nonlinear differential conductance through the Anderson-Holstein quantum dot and find clear signatures of the presence of the phonon mode.

Laakso, M. A.; Kennes, D. M.; Jakobs, S. G.; Meden, V.

2014-02-01

147

Thermalization processes in interacting Anderson insulators  

NASA Astrophysics Data System (ADS)

This paper describes experiments utilizing a unique property of electron glasses to gain information on the fundamental nature of the interacting Anderson-localized phase. The methodology is based on measuring the energy absorbed by the electronic system from alternating electromagnetic fields as a function of their frequency. Experiments on three-dimensional (3D) amorphous indium-oxide films suggest that, in the strongly localized regime, the energy spectrum is discrete and inelastic electron-electron events are strongly suppressed. These results imply that, at low temperatures, electron thermalization and finite conductivity depend on coupling to the phonon bath. The situation is different for samples nearing the metal-insulator transition; in insulating samples that are close to the mobility edge, energy absorption persists to much higher frequencies. Comparing these results with previously studied 2D samples [Ovadyahu, Phys. Rev. Lett. 108, 156602 (2012), 10.1103/PhysRevLett.108.156602] demonstrates that the mean-level spacing (on a single-particle basis) is not the only relevant scale in this problem. The possibility of delocalization by many-body effects and the relevance of a nearby mobility edge (which may be a many-body edge) are discussed.

Ovadyahu, Z.

2015-01-01

148

Local Control Model of Excitation–Contraction Coupling in Skeletal Muscle  

PubMed Central

This is a quantitative model of control of Ca2+ release from the sarcoplasmic reticulum in skeletal muscle, based on dual control of release channels (ryanodine receptors), primarily by voltage, secondarily by Ca2+ (Ríos, E., and G. Pizarro. 1988. NIPS. 3:223–227). Channels are positioned in a double row array of between 10 and 60 channels, where exactly half face voltage sensors (dihydropyridine receptors) in the transverse (t) tubule membrane (Block, B.A., T. Imagawa, K.P. Campbell, and C. Franzini-Armstrong. 1988. J. Cell Biol. 107:2587–2600). We calculate the flux of Ca2+ release upon different patterns of pulsed t-tubule depolarization by explicit stochastic simulation of the states of all channels in the array. Channels are initially opened by voltage sensors, according to an allosteric prescription (Ríos, E., M. Karhanek, J. Ma, A. González. 1993. J. Gen. Physiol. 102:449–482). Ca2+ permeating the open channels, diffusing in the junctional gap space, and interacting with fixed and mobile buffers produces defined and changing distributions of Ca2+ concentration. These concentrations interact with activating and inactivating channel sites to determine the propagation of activation and inactivation within the array. The model satisfactorily simulates several whole-cell observations, including kinetics and voltage dependence of release flux, the “paradox of control,” whereby Ca2+-activated release remains under voltage control, and, most surprisingly, the “quantal” aspects of activation and inactivation (Pizarro, G., N. Shirokova, A. Tsugorka, and E. Ríos. 1997. J. Physiol. 501:289–303). Additionally, the model produces discrete events of activation that resemble Ca2+ sparks (Cheng, H., M.B. Cannell, and W.J. Lederer. 1993. Science (Wash. DC). 262:740–744). All these properties result from the intersection of stochastic channel properties, control by local Ca2+, and, most importantly, the one dimensional geometry of the array and its mesoscopic scale. Our calculations support the concept that the release channels associated with one face of one junctional t-tubule segment, with its voltage sensor, constitute a functional unit, termed the “couplon.” This unit is fundamental: the whole cell behavior can be synthesized as that of a set of couplons, rather than a set of independent channels. PMID:9379173

Stern, Michael D.; Pizarro, Gonzalo; Ríos, Eduardo

1997-01-01

149

Topological approximation of the nonlinear Anderson model.  

PubMed

We study the phenomena of Anderson localization in the presence of nonlinear interaction on a lattice. A class of nonlinear Schrödinger models with arbitrary power nonlinearity is analyzed. We conceive the various regimes of behavior, depending on the topology of resonance overlap in phase space, ranging from a fully developed chaos involving Lévy flights to pseudochaotic dynamics at the onset of delocalization. It is demonstrated that the quadratic nonlinearity plays a dynamically very distinguished role in that it is the only type of power nonlinearity permitting an abrupt localization-delocalization transition with unlimited spreading already at the delocalization border. We describe this localization-delocalization transition as a percolation transition on the infinite Cayley tree (Bethe lattice). It is found in the vicinity of the criticality that the spreading of the wave field is subdiffusive in the limit t?+?. The second moment of the associated probability distribution grows with time as a power law ? t^{?}, with the exponent ?=1/3 exactly. Also we find for superquadratic nonlinearity that the analog pseudochaotic regime at the edge of chaos is self-controlling in that it has feedback on the topology of the structure on which the transport processes concentrate. Then the system automatically (without tuning of parameters) develops its percolation point. We classify this type of behavior in terms of self-organized criticality dynamics in Hilbert space. For subquadratic nonlinearities, the behavior is shown to be sensitive to the details of definition of the nonlinear term. A transport model is proposed based on modified nonlinearity, using the idea of "stripes" propagating the wave process to large distances. Theoretical investigations, presented here, are the basis for consistency analysis of the different localization-delocalization patterns in systems with many coupled degrees of freedom in association with the asymptotic properties of the transport. PMID:25019865

Milovanov, Alexander V; Iomin, Alexander

2014-06-01

150

Local Plasticity of Dendritic Excitability Can Be Autonomous of Synaptic Plasticity and Regulated by Activity-Based Phosphorylation of Kv4.2  

PubMed Central

While plasticity is typically associated with persistent modifications of synaptic strengths, recent studies indicated that modulations of dendritic excitability may form the other part of the engram and dynamically affect computational processing and output of neuronal circuits. However it remains unknown whether modulation of dendritic excitability is controlled by synaptic changes or whether it can be distinct from them. Here we report the first observation of the induction of a persistent plastic decrease in dendritic excitability decoupled from synaptic stimulation, which is localized and purely activity-based. In rats this local plasticity decrease is conferred by CamKII mediated phosphorylation of A-type potassium channels upon interaction of a back propagating action potential (bAP) with dendritic depolarization. PMID:24404150

Labno, Anna; Warrier, Ajithkumar; Wang, Sheng; Zhang, Xiang

2014-01-01

151

Surface excitations in a Bose-Einstein condensate Collective modes which have no radial nodes and are localized close to the surface of  

E-print Network

Surface excitations in a Bose-Einstein condensate Collective modes which have no radial nodes and are localized close to the surface of the condensate are called surface modes. In a semiclassical picture the surface region of the condensate where the density of the thermal cloud is peaked, and should be sensitive

152

Mineralocorticoid receptor blocker eplerenone reduces pain behaviors in vivo and decreases excitability in small diameter sensory neurons from local inflamed dorsal root ganglia in vitro  

PubMed Central

Background Inflammation of the dorsal root ganglia (DRG) may contribute to low back pain, postherpetic neuralgia, and neuropathic pain. The mineralocorticoid receptor (MR) plays a pro-inflammatory role in many non-renal tissues, but its role in peripheral pain at the DRG level is not well studied. Methods Local inflammation of the L5 DRG with the immune activator zymosan rapidly leads to mechanical hypersensitivity and increased excitability of sensory neurons. Using this pain model, we applied the MR antagonist eplerenone locally to the inflamed DRG. Excitability of small diameter sensory neurons was examined in acute primary culture, using patch clamp techniques. Results Local eplerenone significantly reduced the mechanical hypersensitivity and shortened its duration. The same dose was ineffective systemically. Immunohistochemical studies showed the MR was present in most neurons, and rapidly translocated to the nucleus 1 day after local DRG inflammation. Activation of satellite glia (defined by expression of glial fibrillary acidic protein) in the inflamed DRG was also reduced by local eplerenone. Increased excitability of small diameter sensory neurons 1 day after inflammation could be observed in vitro. Eplerenone applied in vitro (8 – 12 hours) could reverse this increased excitability. Eplerenone had no effect in neurons isolated from normal, uninflamed DRG. The MR agonist aldosterone (10 nM) applied in vitro increased excitability of neurons isolated from normal DRG. Conclusions The MR may have a pro-nociceptive role in the DRG. Some of its effects may be mediated by neuronal MR. The MR may represent a novel therapeutic target in some pain syndromes. PMID:23023156

Dong, Fei; Xie, Wenrui; Strong, Judith A.; Zhang, Jun-Ming

2012-01-01

153

Quantum Criticality of Quasi-One-Dimensional Topological Anderson Insulators  

NASA Astrophysics Data System (ADS)

We present an analytic theory of quantum criticality in the quasi-one-dimensional topological Anderson insulators of class AIII and BDI. We describe the systems in terms of two parameters (g, ?) representing localization and topological properties, respectively. Surfaces of half-integer valued ? define phase boundaries between distinct topological sectors. Upon increasing system size, the two parameters exhibit flow similar to the celebrated two-parameter flow describing the class A quantum Hall insulator. However, unlike the quantum Hall system, an exact analytical description of the entire phase diagram can be given. We check the quantitative validity of our theory by comparison to numerical transfer matrix computations.

Altland, Alexander; Bagrets, Dmitry; Fritz, Lars; Kamenev, Alex; Schmiedt, Hanno

2014-05-01

154

A two cities theorem for the parabolic Anderson model  

Microsoft Academic Search

The parabolic Anderson problem is the Cauchy problem for the heat equation $\\\\partial_tu(t,z)=\\\\Delta u(t,z)+\\\\xi(z)u(t,z)$ on $(0,\\\\infty)\\\\times {\\\\mathbb{Z}}^d$ with random potential $(\\\\xi(z):z\\\\in{\\\\mathbb{Z}}^d)$. We consider independent and identically distributed potentials, such that the distribution function of $\\\\xi(z)$ converges polynomially at infinity. If $u$ is initially localized in the origin, that is, if $u(0,{z})={\\\\mathbh1}_0({z})$, we show that, as time goes to infinity, the

Wolfgang König; Hubert Lacoin; Peter Mörters; Nadia Sidorova

2011-01-01

155

The effect of thermal motion on the electron localization in metal-to-ligand charge transfer excitations in [Fe(bpy)3](2+).  

PubMed

Accurate electronic structure calculations of the lowest excited states have been performed on twenty snapshots of a molecular dynamics simulation of [Fe(bpy)3](2+) dissolved in water. The thermal motion distorts the structure of the complex from its average D3 symmetry, causing the localization on one bipyridine ligand of the excited electron in the metal-to-ligand charge transfer (MLCT) state. The excitation energy is about 0.25 eV lower than that for the delocalized description of the MLCT state and is in good agreement with experiments. The composition of the MLCT band is carefully analyzed and the effect of thermal motion on the mechanism of light-induced spin crossover is discussed. PMID:25360630

Domingo, Alex; Sousa, Carmen; de Graaf, Coen

2014-12-21

156

Quantum localization without disorder in interacting Bose-Einstein condensates  

E-print Network

We discuss the possibility of exponential quantum localization in systems of ultracold bosonic atoms with repulsive interactions in open optical lattices without disorder. We show that exponential localization occur in the maximally excited state of the lowest energy band. We establish the conditions under which the presence of the upper energy bands can be neglected, determine the successive stages and the quantum phase boundaries at which localization occurs, and discuss how to detect it experimentally by visibility measurements. The discussed mechanism is a bona fide type of quantum localization, solely due to the interplay between nonlinearity and a bounded energy spectrum. In particular, it does not require the presence of random disorder or other local sources of noise, in striking contrast with Anderson localization.

Franzosi, Roberto; Illuminati, Fabrizio

2010-01-01

157

Universal Fluctuations in Spectra of Disordered Systems at the Anderson Transition  

Microsoft Academic Search

Using the level-spacing distribution and the total probability function of the numbers of levels in a given energy interval we analyze the crossover of the level statistics between the delocalized and the localized regimes. By numerically calculating the electron spectra of systems of up to 323 lattice sites described by the Anderson Hamiltonian it is shown that the distribution P(s)

Isa Zharekeshev; Bernhard Kramer

1995-01-01

158

MD Anderson researchers find that chemotherapy is as effective before breast cancer surgery as after  

Cancer.gov

Whether chemotherapy is given before or after breast-conserving therapy does not have an impact on long-term local-regional outcomes, suggesting treatment success is due more to biologic factors than chemotherapy timing, according to a study by researchers at The University of Texas MD Anderson Cancer Center.

159

H{sub 2} EXCITATION STRUCTURE ON THE SIGHTLINES TO {delta} SCORPII AND {zeta} OPHIUCI: FIRST RESULTS FROM THE SUB-ORBITAL LOCAL INTERSTELLAR CLOUD EXPERIMENT  

SciTech Connect

We present the first science results from the Sub-orbital Local Interstellar Cloud Experiment (SLICE): moderate resolution 1020-1070 A spectroscopy of four sightlines through the local interstellar medium. High signal-to-noise (S/N) spectra of {eta} Uma, {alpha} Vir, {delta} Sco, and {zeta} Oph were obtained during a 2013 April 21 rocket flight. The SLICE observations constrain the density, molecular photoexcitation rates, and physical conditions present in the interstellar material toward {delta} Sco and {zeta} Oph. Our spectra indicate a factor of two lower total N(H{sub 2}) than previously reported for {delta} Sco, which we attribute to higher S/N and better scattered light control in the new SLICE observations. We find N(H{sub 2}) = 1.5 Multiplication-Sign 10{sup 19} cm{sup -2} on the {delta} Sco sightline, with kinetic and excitation temperatures of 67 and 529 K, respectively, and a cloud density of n{sub H} = 56 cm{sup -3}. Our observations of the bulk of the molecular sightline toward {zeta} Oph are consistent with previous measurements (N(H{sub 2}) Almost-Equal-To 3 Multiplication-Sign 10{sup 20} cm{sup -2} at T{sub 01}(H{sub 2}) = 66 K and T{sub exc} = 350 K). However, we detect significantly more rotationally excited H{sub 2} toward {zeta} Oph than previously observed. We infer a cloud density in the rotationally excited component of n{sub H} Almost-Equal-To 7600 cm{sup -3} and suggest that the increased column densities of excited H{sub 2} are a result of the ongoing interaction between {zeta} Oph and its environment; also manifest as the prominent mid-IR bowshock observed by WISE and the presence of vibrationally excited H{sub 2} molecules observed by the Hubble Space Telescope.

France, Kevin; Nell, Nicholas; Kane, Robert; Green, James C. [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, CO 80309 (United States); Burgh, Eric B. [SOFIA/USRA, NASA Ames Research Center, M/S N232-12, Moffett Field, CA 94035 (United States); Beasley, Matthew, E-mail: kevin.france@colorado.edu [Planetary Resources, Inc., 93 S Jackson St 50680, Seattle, WA 98104-2818 (United States)

2013-07-20

160

H2 Excitation Structure on the Sightlines to ? Scorpii and ? Ophiuci: First Results from the Sub-orbital Local Interstellar Cloud Experiment  

NASA Astrophysics Data System (ADS)

We present the first science results from the Sub-orbital Local Interstellar Cloud Experiment (SLICE): moderate resolution 1020-1070 Å spectroscopy of four sightlines through the local interstellar medium. High signal-to-noise (S/N) spectra of ? Uma, ? Vir, ? Sco, and ? Oph were obtained during a 2013 April 21 rocket flight. The SLICE observations constrain the density, molecular photoexcitation rates, and physical conditions present in the interstellar material toward ? Sco and ? Oph. Our spectra indicate a factor of two lower total N(H2) than previously reported for ? Sco, which we attribute to higher S/N and better scattered light control in the new SLICE observations. We find N(H2) = 1.5 × 1019 cm-2 on the ? Sco sightline, with kinetic and excitation temperatures of 67 and 529 K, respectively, and a cloud density of n H = 56 cm-3. Our observations of the bulk of the molecular sightline toward ? Oph are consistent with previous measurements (N(H2) ? 3 × 1020 cm-2 at T 01(H2) = 66 K and T exc = 350 K). However, we detect significantly more rotationally excited H2 toward ? Oph than previously observed. We infer a cloud density in the rotationally excited component of n H ? 7600 cm-3 and suggest that the increased column densities of excited H2 are a result of the ongoing interaction between ? Oph and its environment; also manifest as the prominent mid-IR bowshock observed by WISE and the presence of vibrationally excited H2 molecules observed by the Hubble Space Telescope.

France, Kevin; Nell, Nicholas; Kane, Robert; Burgh, Eric B.; Beasley, Matthew; Green, James C.

2013-07-01

161

OPERATIONAL K-THEORY DAVE ANDERSON AND SAM PAYNE  

E-print Network

OPERATIONAL K-THEORY DAVE ANDERSON AND SAM PAYNE Abstract. We study the operational bivariant ANDERSON AND SAM PAYNE plays a central role in one of the classical formulations of Riemann-Roch the- orems

Payne, Sam

162

Universality and the QCD Anderson transition.  

PubMed

We study the Anderson-type transition previously found in the spectrum of the QCD quark Dirac operator in the high-temperature, quark-gluon plasma phase. Using finite size scaling for the unfolded level spacing distribution, we show that in the thermodynamic limit there is a genuine mobility edge, where the spectral statistics changes from Poisson to Wigner-Dyson statistics in a nonanalytic way. We determine the correlation length critical exponent ? and find that it is compatible with that of the unitary Anderson model. PMID:24679282

Giordano, Matteo; Kovács, Tamás G; Pittler, Ferenc

2014-03-14

163

The University of Texas MD Anderson Cancer Center  

Cancer.gov

The University of Texas MD Anderson Cancer Center (MD Anderson) was established by the Texas State Legislature in 1941. In 1971, after the passage of the National Cancer Act, MD Anderson became one of the nation’s first NCI-designated comprehensive cancer centers.

164

Time-dependent localized Hartree-Fock density-functional linear response approach for photoionization of atomic excited states  

E-print Network

of atomic systems. This approach employs a spin-dependent localized Hartree- Fock exchange potential-shell 23 and open-shell 24 atomic systems. In this paper, we present a time-dependent localized HartreeTime-dependent localized Hartree-Fock density-functional linear response approach

Chu, Shih-I

165

Free-Breathing Inner-Volume Black-Blood Imaging of the Human Heart Using Two-dimensionally Selective Local Excitation at 3T  

PubMed Central

Black-blood fast spin-echo imaging is a powerful technique for the evaluation of cardiac anatomy. To avoid fold-over artifacts, using a sufficiently large field of view in phase-encoding direction is mandatory. The related oversampling affects scanning time and respiratory chest motion artifacts are commonly observed. The excitation of a volume that exclusively includes the heart without its surrounding structures may help to improve scan efficiency and minimize motion artifacts. Therefore, and by building on previously reported inner-volume approach, the combination of a black-blood FSE sequence with a two-dimensionally selective radiofrequency pulse is proposed for selective “local excitation” small-FOV imaging of the heart. This local excitation technique has been developed, implemented, and tested in phantoms and in vivo. With this method, small-FOV imaging of a user-specified region in the human thorax is feasible, scanning becomes more time efficient, motion artifacts can be minimized and additional flexibility in the choice of imaging parameters can be exploited. PMID:22161817

Abd-Elmoniem, Khaled Z.; Barmet, Christoph; Stuber, Matthias

2011-01-01

166

Biology Office Shauna C. Anderson, Director  

E-print Network

Biology Biology Office Shauna C. Anderson, Director 375 WIDB, (801) 422-4295 College of Biology program in biology has open enrollment. The Discipline A degree for students who desire a broad approach to biology, the major provides solid preparation for graduate schools in most fields of biology as well

Hart, Gus

167

Visual Absorption Capability1 Lee Anderson  

E-print Network

Visual Absorption Capability1 Lee Anderson 2a/ Jerry Mosier 2b/ Geoffrey Chandler 2c/ 1/ Submitted, Lassen National Forest, Susanville, California. Abstract: Visual absorption capability (VAC) is a tool development which is in harmony with the visual resource vis- ual absorption capability (VAC) is a tool which

Standiford, Richard B.

168

The conductivity measure for the Anderson model  

E-print Network

We study the ac-conductivity in linear response theory for the Anderson tight-binding model. We define the electrical ac-conductivity and calculate the linear-response current at zero temperature for arbitrary Fermi energy. In particular, the Fermi energy may lie in a spectral region where extended states are believed to exist.

Abel Klein; Peter Müller

2007-09-21

169

The Anderson Quin Cycle. Final report  

SciTech Connect

The objective of this study was to make a more refined evaluation of the Anderson Quin Cycle based on most recent information on the performance of various elements that will be used in the Anderson Quin Cycle. My original estimate of the work plan for evaluating and optimizing the Anderson Quin Cycle called for 7000 man hours of work. Since this grant was limited to 2150 man hours, we could not expect to achieve all the objectives within the allotted period of work. However, the most relevant program objectives have been completed as reported here. The analysis generally confirms the results originally estimated in my paper on the subject. (Ref. 2) Further optimizations should show even higher efficiencies. The Anderson Quin Cycle (US Patent applied for) basically consists of 5 elements in the power cycle: A refrigeration system to cool and clean the inlet air before it enters the compressor that supplies air for the gas turbine; a gas turbine consisting of a compressor, combustor, and turbine; a steam boiler and steam turbine system using the heat from the exhaust gas out of the gas turbine; a vapor turbine cycle, which utilizes the condensed heat from the exhaust of the steam turbine and the exhaust gas heat leaving the steam boiler to operate a vapor turbine cycle which utilizes another fluid than water, in this case isobutane; and the fifth element consists of a gas cooler and heat pump system, which removes the heat from the exhaust gas to lower its temperature essentially to atmospheric temperature, and at the same time permits treatment of the exhaust gas to remove acid components such as sulfur dioxide and nitrogen oxides. Current industry accepted component characteristics were incorporated in the performance analysis of the overall cycle, ensuring accurate and meaningful operating predictions. The characteristics and performance of each of the elements are described. The thermal efficiency of the optimized calculated Anderson Quin Cycle is 62 percent.

Anderson, J.H.; Bilbow, W.M.

1993-03-18

170

Nonatomic Mutual Exclusion with Local Spinning # (Extended Abstract)  

E-print Network

. This algorithm is derived from Yang and Anderson's atomic tree­based local­spin algorithm in a way that preservesNonatomic Mutual Exclusion with Local Spinning # (Extended Abstract) James H. Anderson and Yong}@cs.unc.edu ABSTRACT We present an N­process local­spin mutual exclusion algorithm, based on nonatomic reads and writes

Anderson, James

171

Nonatomic Mutual Exclusion with Local Spinning (Extended Abstract)  

E-print Network

. This algorithm is derived from Yang and Anderson's atomic tree-based local-spin algorithm in a way that preservesNonatomic Mutual Exclusion with Local Spinning (Extended Abstract) James H. Anderson and Yong}@cs.unc.edu ABSTRACT We present an N-process local-spin mutual exclusion algorithm, based on nonatomic reads and writes

Anderson, James

172

The atomic approach to the Anderson model for the finite U case: application to a quantum dot.  

PubMed

In the present work we apply the atomic approach to the single-impurity Anderson model (SIAM). A general formulation of this approach, that can be applied both to the impurity and to the lattice Anderson Hamiltonian, was developed in a previous work (Foglio et al 2009 arxiv: 0903.0139v2 [cond-mat.str-el]). The method starts from the cumulant expansion of the periodic Anderson model, employing the hybridization as a perturbation. The atomic Anderson limit is analytically solved and its sixteen eigenenergies and eigenstates are obtained. This atomic Anderson solution, which we call the AAS, has all the fundamental excitations that generate the Kondo effect, and in the atomic approach is employed as a 'seed' to generate the approximate solutions for finite U. The width of the conduction band is reduced to zero in the AAS, and we choose its position such that the Friedel sum rule is satisfied, close to the chemical potential mu. We perform a complete study of the density of states of the SIAM over the whole relevant range of parameters: the empty dot, intermediate valence, Kondo and magnetic regimes. In the Kondo regime we obtain a density of states that characterizes well the structure of the Kondo peak. To show the usefulness of the method we have calculated the conductance of a quantum dot, side-coupled to a conduction band. PMID:20571194

Lobo, T; Figueira, M S; Foglio, M E

2010-07-01

173

Excited state localization and internuclear interactions in asymmetric ruthenium(II) and osmium(II) bpy/tpy based dinuclear compounds.  

PubMed

The synthesis of two asymmetric dinuclear complexes with the formula [M(bpy)(2)(bpt)Ru(tpy)Cl](2+), where M = Ru (1a), Os(2a); bpy = 2,2'-bipyridyl; Hbpt = 3,5-bis(pyridin-2-yl)1,2,4-triazole and tpy = 2,2',6',2''-terpyridine, is reported. The compounds obtained are characterized by mass spectrometry, (1)H NMR, UV/vis/NIR absorption, luminescence, and resonance Raman spectroscopy. Deuterium isotope labeling facilitates assignment of the (1)H NMR and resonance Raman spectra. The interaction between the two metal centers, mediated by the bridging 1,2,4-triazolato moiety in the mixed valent state, is assigned as type II based on the observation of metal to metal charge transfer absorption bands at 7090 and 5990 cm(-1) for 1a and 2a, respectively. The extent of localization of the emissive excited state was determined by transient resonance Raman and emission spectroscopy. Both 1a and 2a show phosphorescence at the same wavelengths; however, whereas for compound 1a the emission is based on the Ru(tpy)Cl- center, for 2a the emissive state is localized on the Os(bpy)(2)- unit. This indicates that also in the excited state there is efficient interaction between the two metal centers. PMID:20141180

Halpin, Yvonne; Dini, Danilo; Ahmed, Hamid M Younis; Cassidy, Lynda; Browne, Wesley R; Vos, Johannes G

2010-03-15

174

On the mean square distance in the Anderson model  

NASA Astrophysics Data System (ADS)

In this dissertation, we study dynamical localization via the mean square distance traveled by a particle up to time t > 0 in the Anderson model in a d-dimensional lattice Zd . Assuming a common single-site probability distribution mu has a density, using the Heisenberg position and momentum operators, and applying the Trotter product theorem, we formulate our problem in terms of oscillatory integrals in momentum space. Among the results obtained, we prove that a finite Trotter approximation to the averaged mean square distance exhibits, at worst, a diffusive behavior for large t in dimensions d ? 3 provided that the Fourier transform of the single-site probability, m? is in L2( R ).

Suwanna, Sujin

175

Universal Knight shift anomaly in the periodic Anderson model  

NASA Astrophysics Data System (ADS)

We report a determinant Quantum Monte Carlo investigation which quantifies the behavior of the susceptibility and the entropy in the framework of the periodic Anderson model, focusing on the evolution with different degree of conduction electron (c )-local moment (f ) hybridization. These results capture the behavior observed in several experiments, including the universal behavior of the NMR Knight shift anomaly below the crossover temperature T*. We find that T* is a measure of the onset of c - f correlations and grows with increasing hybridization. These results suggest that the NMR Knight shift and spin-lattice relaxation rate measurements in non-Fermi-liquid materials are strongly influenced by the temperature dependence of the c - f kinetic energy. Our results provide a microscopic basis for the phenomenological two-fluid model of Kondo lattice behavior, and its evolution with pressure and temperature.

Jiang, M.; Curro, N. J.; Scalettar, R. T.

2014-12-01

176

MD Anderson-led study finds LIFR protein suppresses breast cancer metastasis  

Cancer.gov

A receptor protein suppresses local invasion and metastasis of breast cancer cells, the most lethal aspect of the disease, according to a research team headed by scientists from The University of Texas MD Anderson Cancer Center. Reporting in Nature Medicine, the team described using high-throughput RNA sequencing to identify the leukemia inhibitory factor receptor (LIFR) as a novel suppressor of breast cancer metastasis, the spread of the disease to other organs.

177

A note on fractional moments for the one-dimensional continuum Anderson model  

E-print Network

We give a proof of dynamical localization in the form of exponential decay of spatial correlations in the time evolution for the one-dimensional continuum Anderson model via the fractional moments method. This follows via exponential decay of fractional moments of the Green function, which is shown to hold at arbitrary energy and for any single-site distribution with bounded, compactly supported density.

Eman Hamza; Robert Sims; Günter Stolz

2009-07-27

178

ROBERT CORNELL Head and Wilton T. Anderson Chair  

E-print Network

ROBERT CORNELL Head and Wilton T. Anderson Chair BRADLEY BLAYLOCK Assistant Professor RICHARD Professor ANGELA SPENCER Clinical Associate Professor and Haskell Cudd Professor LINDA STONE Administrative

Veiga, Pedro Manuel Barbosa

179

Magnetic field induced quantum phase transitions in the two-impurity Anderson model  

SciTech Connect

In the two-impurity Anderson model, the inter-impurity spin exchange interaction favors a spin singlet state between two impurities leading to the localization of quasiparticles. We show that a local uniform magnetic field can delocalize the quasiparticies to restore the Kondo resonance. This transition is found to be continuous, accompanied by not only the divergence of the staggered (anti ferromagnetic) susceptibility, but also the divergence of the uniform spin susceptibility. This implies that the magnetic field induced quantum phase transitions in Kondo systems are in favor of the local critical type.

Zhu, Lujun [Los Alamos National Laboratory; Zhu, Jian - Xin [Los Alamos National Laboratory

2010-11-17

180

Strong-coupling limit of depleted Kondo-and Anderson-lattice models Irakli Titvinidze, Andrej Schwabe and Michael Potthoff  

E-print Network

Strong-coupling limit of depleted Kondo- and Anderson-lattice models Irakli Titvinidze, Andrej an effective low- energy Hamiltonian for the Kondo-lattice model with a depleted system of localized spins.10.-b, 75.20.Hr, 75.30.Mb I. INTRODUCTION The Kondo-lattice model1­5 is a prototypical model

Potthoff, Michael

181

Conservation laws, radiative decay rates, and excited state localization in organometallic complexes with strong spin-orbit coupling  

E-print Network

There is longstanding fundamental interest in 6-fold coordinated $d^6$ ($t_{2g}^6$) transition metal complexes such as [Ru(bpy)$_3$]$^{2+}$ and Ir(ppy)$_3$, particularly their phosphorescence. This interest has increased with the growing realisation that many of these complexes have potential uses in applications including photovoltaics, imaging, sensing, and light-emitting diodes. In order to design new complexes with properties tailored for specific applications a detailed understanding of the low-energy excited states, particularly the lowest energy triplet state, $T_1$, is required. Here we describe a model of pseudo-octahedral complexes based on a pseudo-angular momentum representation and show that the predictions of this model are in excellent agreement with experiment - even when the deviations from octahedral symmetry are large. This model gives a natural explanation of zero-field splitting of $T_1$ and of the relative radiative rates of the three sublevels in terms of the conservation of time-revers...

Powell, B J

2015-01-01

182

Synergy effects of electric and magnetic fields on locally excited-state fluorescence of photoinduced electron transfer systems in a polymer film.  

PubMed

Photoluminescence of electron donor-acceptor pairs that show photoinduced electron transfer (PIET) has been measured in a polymer film under simultaneous application of electric field and magnetic field. Fluorescence emitted from the locally excited state (LE fluorescence) of 9-methylanthracene (MAnt) and pyrene (Py) is quenched by an electric field in a mixture of 1,3-dicyanobenzene (DCB) with MAnt or Py, indicating that PIET from the excited state of MAnt or Py to DCB is enhanced by an electric field. Simultaneous application of electric and magnetic fields enhances the reverse process from the radical-ion pair produced by PIET to the LE fluorescent state of MAnt or Py. As a result, the electric-field-induced quenching of the LE fluorescence is reduced by application of the magnetic fields. Thus, the synergy effect of electric and magnetic fields is observed on the LE fluorescence of MAnt or Py. Exciplex fluorescence spectra resulting from PIET can be obtained by analyzing the field effects on photoluminescence spectra, even when the exciplex fluorescence is too weak to be determined from the steady-state or time-resolved photoluminescence spectra at zero field. PMID:19791808

Awasthi, Kamlesh; Iimori, Toshifumi; Ohta, Nobuhiro

2009-10-01

183

Synergy Effects of Electric and Magnetic Fields on Locally Excited-State Fluorescence of Photoinduced Electron Transfer Systems in a Polymer Film  

NASA Astrophysics Data System (ADS)

Photoluminescence of electron donor-acceptor pairs that show photoinduced electron transfer (PIET) has been measured in a polymer film under simultaneous application of electric field and magnetic field. Fluorescence emitted from the locally excited state (LE fluorescence) of 9-methylanthracene (MAnt) and pyrene (Py) is quenched by an electric field in a mixture of 1,3-dicyanobenzene (DCB) with MAnt or Py, indicating that PIET from the excited state of MAnt or Py to DCB is enhanced by an electric field. Simultaneous application of electric and magnetic fields enhances the reverse process from the radical-ion pair produced by PIET to the LE fluorescent state of MAnt or Py. As a result, the electric-field-induced quenching of the LE fluorescence is reduced by application of the magnetic fields. Thus, the synergy effect of electric and magnetic fields is observed on the LE fluorescence of MAnt or Py. Exciplex fluorescence spectra resulting from PIET can be obtained by analyzing the field effects on photoluminescence spectra, even when the exciplex fluorescence is too weak to be determined from the steady-state or time-resolved photoluminescence spectra at zero field.

Awasthi, Kamlesh; Iimori, Toshifumi; Ohta, Nobuhiro

2009-09-01

184

Local magnetic properties of multiferroic Nd0.5Gd0.5Fe3(BO3)4 in the excited states of Nd3+ ion  

NASA Astrophysics Data System (ADS)

Polarized absorption spectra of single-crystal Nd0.5Gd0.5Fe3(BO3)4 were studied in the region of the transition 4I9/2?(4G5/2+2G7/2) in Nd3+ ion as a function of temperature (2-34 K) and magnetic field (0-65 kOe). The spectra of natural circular dichroism were measured in the range of 5-40 K. It was found out that the local magnetic properties in the vicinity of the excited ion substantially depended on its state. In particular, a weak ferromagnetic moment appears in some excited states. It was found out that the selection rules for electron transitions in the magnetically ordered state substantially deviated from those in the paramagnetic state of the crystal. They are different for different transitions and they are very sensitive to the orientation of the sublattice magnetic moment relative to the light polarization. In the spectrum of the natural circular dichroism, the transition is revealed which is not observed in the absorption spectrum.

Malakhovskii, A. V.; Gnatchenko, S. L.; Kachur, I. S.; Piryatinskaya, V. G.; Sukhachev, A. L.; Temerov, V. L.

2015-02-01

185

Local optical emission spectroscopy of excited species effused from an evaporation cell and a sputter source into dense plasmas - Basic studies for the deposition of thin gradient films.  

PubMed

Space resolved optical emission spectroscopy has been applied to determine the distribution of excited species in dense plasmas which are used for the deposition of thin coatings. Typical electron densities and electron temperatures in the plasma facility PETRA ( Plasma Engineering and Technology Research Assembly) are in the range of n(e) = 10(12) cm(-3) and T(e) = 10 eV. During the deposition process material (Al) is evaporated from a vapour cell under controlled conditions. The vapour stream is guided into a dense plasma which is composed of inert gas, Ar or He, and hydrocarbon species produced from the dissociation of C(2)H(2). The evaporated Al-stream which travels with thermal velocity into a plasma of high electron density, is nearly completely ionized due to the short mean free path for electron impact ionization in the above mentioned parameter range. Optical emission spectroscopy has been applied to investigate the interaction processes between the vapour stream and the plasma as well as the transport of the ionized Al along the applied magnetic field. For the measurements space resolved optical emission spectroscopy with an in-situ translation mechanism of the optical fibre has been used to measure the local concentrations of excited Al neutrals and ions as well as the concentration of the background plasma species. PMID:15045374

Bolt, H; Hemel, V; Koch, F; Nickel, H

1996-06-01

186

Maximizing singlet fission in organic dimers: theoretical investigation of triplet yield in the regime of localized excitation and fast coherent electron transfer.  

PubMed

In traditional solar cells one photon absorbed can lead to at most one electron of current. Singlet fission, a process in which one singlet exciton is converted to two triplet excitons, provides a potential improvement by producing two electrons from each photon of sufficient energy. The literature contains several reports of singlet fission in various systems, but the mechanism of this process is poorly understood. In this paper we examine a two-step mechanism with a charge transfer state intermediate, applicable when the initial excited state is localized. Density matrix theory is used to examine how various molecular properties such as orbital energies and electronic couplings affect singlet fission yield in the regime of fast, coherent electron transfer. Several promising chromophores are discussed and density functional theory is used to predict fission yield for each in the context of this mechanism. Finally, implications for chromophore design are discussed, and future experiments are suggested. PMID:20184354

Greyson, Eric C; Vura-Weis, Josh; Michl, Josef; Ratner, Mark A

2010-11-18

187

Lyapunov Exponents for Unitary Anderson Models  

E-print Network

We study a unitary version of the one-dimensional Anderson model, given by a five diagonal deterministic unitary operator multiplicatively perturbed by a random phase matrix. We fully characterize positivity and vanishing of the Lyapunov exponent for this model throughout the spectrum and for arbitrary distributions of the random phases. This includes Bernoulli distributions, where in certain cases a finite number of critical spectral values, with vanishing Lyapunov exponent, exists. We establish similar results for a unitary version of the random dimer model.

Eman Hamza; Günter Stolz

2006-11-28

188

Detection of Influenza Virus with Specific Subtype by Using Localized Surface Plasmons Excited on a Flat Metal Surface  

NASA Astrophysics Data System (ADS)

We report on a method to determine subtype of influenza viruses by using surface plasmons localized in microscopic region on a flat metal surface. In this method, refractive index variation arisen from interactions between viruses and their monoclonal antibodies is measured. The developed sensor shows stability of refractive index in the order of 10-4 against sample exchange. In our experiment, A/H1N1 viruses are distinguished from A/H3N2 viruses by using monoclonal antibodies immobilized on the metal surface. Since the measurement probe has the volume of ?6 al, the method has potential to handle multiple subtypes in the measurement of a sample with ultra small volume.

Ning, Jun; Nagata, Kotaro; Ainai, Akira; Hasegawa, Hideki; Kano, Hiroshi

2013-08-01

189

Participant List and Biographies Cheryl Anderson, canderso@hawaii.edu  

E-print Network

- 92 - APPENDIX A Participant List and Biographies Cheryl Anderson, canderso@hawaii.edu Social Science Research Institute, University of Hawai`i C heryl L. Anderson is a certified planner (AICP), doctoral candidate, and the Director of the Hazards, Climate, and Environment Program, University of Hawai`i

Colorado at Boulder, University of

190

The Economics of Censorship Resistance George Danezis and Ross Anderson  

E-print Network

The Economics of Censorship Resistance George Danezis and Ross Anderson University of Cambridge.Anderson)@cl.cam.ac.uk Abstract. We propose the first economic model of censorship resis- tance. Early peer-to-peer systems Internet. An alternative approach is to encourage nodes to serve re- sources they are interested in. Both

Danezis, George

191

Magnetoresistance of an Anderson Insulator of Bosons Anirban Gangopadhyay,1  

E-print Network

Magnetoresistance of an Anderson Insulator of Bosons Anirban Gangopadhyay,1 Victor Galitski,1 March 2013; published 9 July 2013) We study the magnetoresistance of two-dimensional bosonic Anderson is magnetoresistance (MR). This is because a magnetic field sensitively affects the quantum interference, which in turn

Müller, Markus

192

Anderson Localization for the Almost Mathieu Equation: A Nonperturbative Proof.  

E-print Network

:4: \\Lambda Permanent address: International Institute of Earthquake Prediction Theory and Mathematical Geo . It is well known that for irrational ! both oe and oe pp (understood as the closure of the set of eigenvalues, â?? and !; is very nontrivial. For â?? ? 2 and irrational ! the Lyapunov exponent is positive; that proves the absence

193

Universal metallic and insulating properties of one dimensional Anderson Localization  

E-print Network

Landauer study Guillaume Paulin and David Carpentier CNRS UMR 5672 - Laboratoire de Physique de l's function technique. We stay near the band center, avoiding the presence of fluctuating states studied

Paris-Sud XI, Université de

194

Passive control of buckling deformation via Anderson Localization Phenomenon  

NASA Technical Reports Server (NTRS)

Buckling problems of two types of multi-span elastic plates with transverse stiffeners are considered using a method based on the finite difference calculus. The discreteness of the stiffeners is accounted for. It is found that the torsional rigidity of the stiffener plays an important role in the buckling mode pattern. When the torsional rigidity is properly adjusted, the stiffener can act as an isolator of deformation for the structure at buckling so that the deflection is only limited to a small area.

Elishakoff, Isaac; Li, Y. W.; Starnes, J. H., Jr.

1998-01-01

195

The Role of Contrast in the Perception of Achromatic Transparency: Comment on Singh and Anderson (2002) and Anderson (2003)  

ERIC Educational Resources Information Center

M. Singh and B. L. Anderson proposed a perceptual theory of achromatic transparency in which the perceived transmittance of a perceived transparent filter is determined by the ratio of the Michelson contrast seen in the region of transparency to that of the background seen directly. Subsequently, B. L. Anderson, M. Singh, and J. Meng proposed that…

Albert, Marc K.

2008-01-01

196

Critical State of the Anderson Transition: Between a Metal and an Insulator  

SciTech Connect

Using a three-frequency one-dimensional kicked rotor experimentally realized with a cold atomic gas, we study the transport properties at the critical point of the metal-insulator Anderson transition. We accurately measure the time evolution of an initially localized wave packet and show that it displays at the critical point a scaling invariance characteristic of this second-order phase transition. The shape of the momentum distribution at the critical point is found to be in excellent agreement with the analytical form deduced from the self-consistent theory of localization.

Lemarie, Gabriel; Delande, Dominique [Laboratoire Kastler Brossel, UPMC-Paris 6, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France); Lignier, Hans; Szriftgiser, Pascal; Garreau, Jean Claude [Laboratoire de Physique des Lasers, Atomes et Molecules, Universite Lille 1 Sciences et Technologies, UMR CNRS 8523, F-59655 Villeneuve d'Ascq Cedex (France)

2010-08-27

197

Between a metal and an insulator: the critical state of the Anderson transition  

E-print Network

Using a three-frequency one-dimensional kicked rotor experimentally realized with a cold atomic gas, we study the transport properties at the critical point of the metal-insulator Anderson transition. We accurately measure the time-evolution of an initially localized wavepacket and show that it displays at the critical point a scaling invariance characteristic of this second-order phase transition. The shape of the momentum distribution at the critical point is found to be in excellent agreement with the analytical form deduced from self-consistent theory of localization.

Gabriel Lemarié; Hans Lignier; Dominique Delande; Pascal Szriftgiser; Jean Claude Garreau

2010-05-10

198

A topological approximation of the nonlinear Anderson model  

E-print Network

We study the phenomena of Anderson localization in the presence of nonlinear interaction on a lattice. A class of nonlinear Schrodinger models with arbitrary power nonlinearity is analyzed. We conceive the various regimes of behavior, depending on the topology of resonance-overlap in phase space, ranging from a fully developed chaos involving Levy flights to pseudochaotic dynamics at the onset of delocalization. It is demonstrated that quadratic nonlinearity plays a dynamically very distinguished role in that it is the only type of power nonlinearity permitting an abrupt localization-delocalization transition with unlimited spreading already at the delocalization border. We describe this localization-delocalization transition as a percolation transition on a Cayley tree. It is found in vicinity of the criticality that the spreading of the wave field is subdiffusive in the limit t\\rightarrow+\\infty. The second moment grows with time as a powerlaw t^\\alpha, with \\alpha = 1/3. Also we find for superquadratic nonlinearity that the analog pseudochaotic regime at the edge of chaos is self-controlling in that it has feedback on the topology of the structure on which the transport processes concentrate. Then the system automatically (without tuning of parameters) develops its percolation point. We classify this type of behavior in terms of self-organized criticality dynamics in Hilbert space. For subquadratic nonlinearities, the behavior is shown to be sensitive to details of definition of the nonlinear term. A transport model is proposed based on modified nonlinearity, using the idea of stripes propagating the wave process to large distances. Theoretical investigations, presented here, are the basis for consistency analysis of the different localization-delocalization patterns in systems with many coupled degrees of freedom in association with the asymptotic properties of the transport.

Alexander V. Milovanov; Alexander Iomin

2014-06-05

199

Effects of cyclosis on chloroplast-cytoplasm interactions revealed with localized lighting in Characean cells at rest and after electrical excitation.  

PubMed

Cytoplasmic streaming in Characean internodes enables rapid intracellular transport and facilitates interactions between spatially remote cell regions. Cyclosis-mediated distant interactions might be particularly noticeable under nonuniform illumination, in the vicinity of light-shade borders where metabolites are transported between functionally distinct cell regions. In support of this notion, chlorophyll fluorescence parameters assessed on a microscopic area of Chara corallina internodal cells (area of inspection, AOI) responded to illumination of nearby regions in asymmetric manner depending on the vector of cytoplasmic streaming. When a beam of white light was applied through a 400-?m optic fiber upstream of AOI with regard to the direction of cytoplasmic streaming, non-photochemical quenching (NPQ) developed after a lag period in AOI exposed to moderate intensity light. Conversely, no NPQ was induced in the same cell area when the beam position was shifted to an equal distance downstream of AOI. Light-response curves for the efficiency of photosystem II electron transport in chloroplasts differed markedly depending on the illumination pattern (whole-cell versus small area illumination) but these differences were eliminated after the inhibition of cytoplasmic streaming with cytochalasin B. Localized illumination promoted chloroplast fluorescence responses to electrical plasmalemma excitation at high light intensities, which contrasts to the requirement of low to moderate irradiances for observation of the stimulus-response coupling under whole-cell illumination. The results indicate that different photosynthetic capacities of chloroplasts under general and localized illumination are related to lateral transport of nonevenly distributed cytoplasmic components between the cell parts with dominant photosynthetic and respiratory metabolism. PMID:21708122

Bulychev, Alexander A; Dodonova, Svetlana O

2011-09-01

200

A struggle for freedom; Maxwell Anderson, 1938-1952  

E-print Network

the Sudetenland to 7William L. Langer and S. Everett Gleason, The Challen e to Isolation: The World Crisis of 1937-1940 and American Forei n Polic (New York, 195Z), 14. 16 Germany in exchange for the Fuhrer's promise to cease demands for more European..., November 2, 1940, XII, I, 25 Anderson to Collier Young, June 30, 1939; Sidney Lipsitch to Anderson, July 3, 1939, MAC, HRC. By late 1942, Anderson was still refusing to apply for social security. See Robert Rice, "Maxwell Ander- son: A Character Study...

Odeski, Thomas Francis

2012-06-07

201

Anderson metal-insulator transitions with classical magnetic impurities  

NASA Astrophysics Data System (ADS)

We study the effects of classical magnetic impurities on the Anderson metal-insulator transition (AMIT) numerically. In particular we find that while a finite concentration of Ising impurities lowers the critical value of the site-diagonal disorder amplitude Wc, in the presence of Heisenberg impurities, Wc is first increased with increasing exchange coupling strength J due to time-reversal symmetry breaking. The resulting scaling with J is compared to analytical predictions by Wegner [1]. The results are obtained numerically, based on a finite-size scaling procedure for the typical density of states [2], which is the geometric average of the local density of states. The latter can efficiently be calculated using the kernel polynomial method [3]. Although still suffering from methodical shortcomings, our method proves to deliver results close to established results for the orthogonal symmetry class [4]. We extend previous approaches [5] by combining the KPM with a finite-size scaling analysis. We also discuss the relevance of our findings for systems like phosphor-doped silicon (Si:P), which are known to exhibit a quantum phase transition from metal to insulator driven by the interplay of both interaction and disorder, accompanied by the presence of a finite concentration of magnetic moments [6].

Jung, Daniel; Kettemann, Stefan

2014-08-01

202

MD Anderson study finds cancer related pain often undertreated  

Cancer.gov

More than one third of patients with invasive cancer are undertreated for their pain, with minorities twice as likely to not receive analgesics, according to research from The University of Texas MD Anderson Cancer Center.

203

Taking on Titan: Meet Carrie Anderson - Duration: 2:45.  

NASA Video Gallery

When she was a little girl, Carrie Anderson dreamed of becoming an astronomer. Now, as a space scientist at NASA Goddard Space Flight Center, Carrie studies the atmosphere on Titan: one of Saturn's...

204

Magnetic Moments of Chromium-Doped Gold Clusters: The Anderson Impurity Model in Finite Systems  

E-print Network

The magnetic moment of a single impurity atom in a finite free electron gas is studied in a combined x-ray magnetic circular dichroism spectroscopy and density functional theory study of size-selected free chromium-doped gold clusters. The observed size-dependence of the local magnetic moment can essentially be understood in terms of the Anderson impurity model. Electronic shell closure in the host metal minimizes the interaction of localized impurity states with the confined free electron gas and preserves the full magnetic moment of $\\unit[5]{\\mu_B}$ in $\\mathrm{CrAu}_{2}^{+}$ and $\\mathrm{CrAu}_{6}^{+}$ clusters. Even for open-shell species, large local moments are observed that scale with the energy gap of the gold cluster. This indicates that an energy gap in the free electron gas generally stabilizes the local magnetic moment of the impurity.

Hirsch, K; Langenberg, A; Niemeyer, M; Langbehn, B; Möller, T; Terasaki, A; Issendorff, B v; Lau, J T

2013-01-01

205

Dystopian Visions of Global Capitalism: Philip Reeve’s Mortal Engines and M.T Anderson’s Feed  

Microsoft Academic Search

This article examines Philip Reeve’s novel for children, Mortal Engines, and M.T. Anderson’s young adult novel, Feed, by assessing these dystopias as prototypical texts of what Ulrich Beck calls risk society. Through their visions of a fictional\\u000a future, the two narratives explore the hazards created by contemporary techno-economic progress, predatory global politics\\u000a and capitalist excesses of consumption. They implicitly pose

Elizabeth Bullen; Elizabeth Parsons

2007-01-01

206

Scaling properties near the Anderson transition  

NASA Astrophysics Data System (ADS)

We present detailed results of analytical and numerical investigations of the Anderson metal-insulator (MI) transition based on a supersymmetric nonlinear ? model in the effective-medium approximation. We show that in the critical metallic regime the density-of-states correlation function has two characteristic length scales ? and ? which diverge according to a power law but have different critical exponents. Moreover, we derive that the level broadening depends exponentially on the shorter length ? and put forward a physical interpretation that enables us to express the diffusion coefficient in terms of these two lengths. We argue that in the vicinity of the MI transition the properties of the system are determined by the correlation length ?, which is related to the typical size of classically forbidden regions, and the phase-coherence length, which sets the scale for self-averaging of the density-of-states correlator. Relating the level broadening due to tunneling along a distance ? and the Thouless length, we reproduce earlier results on the critical exponential behavior of the diffusion coefficient.

Efetov, K. B.; Viehweger, O.

1992-05-01

207

The ground state energy of the Edwards-Anderson Ising spin glass with a hybrid genetic algorithm  

Microsoft Academic Search

Ground states of three-dimensional Edwards-Anderson ±J Ising spin glasses were calculated with a hybrid of genetic algorithm and local optimization. The algorithm was fast and reliable enough to allow extensive calculations for systems of linear size between 3 and 14 and determination of the average ground state energies with small errors. A linear dependence on 1\\/volume approximates the data very

Károly F. Pál

1996-01-01

208

Localization of Cold Atoms in State-Dependent Optical Lattices via a Rabi Pulse  

SciTech Connect

We propose a novel realization of Anderson localization in nonequilibrium states of ultracold atoms in an optical lattice. A Rabi pulse transfers part of the population to a different internal state with infinite effective mass. These frozen atoms create a quantum superposition of different disorder potentials, localizing the mobile atoms. For weakly interacting mobile atoms, Anderson localization is obtained. The localization length increases with increasing disorder and decreasing interaction strength, contrary to the expectation for equilibrium localization.

Horstmann, Birger; Duerr, Stephan [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching (Germany); Roscilde, Tommaso [Laboratoire de Physique, CNRS UMR 5672, Ecole Normale Superieure de Lyon, Universite de Lyon, 46 Allee d'Italie, Lyon, F-69364 (France)

2010-10-15

209

Topology of delocalization in the nonlinear Anderson model and anomalous diffusion on finite clusters  

E-print Network

This study is concerned with destruction of Anderson localization by a nonlinearity of the power-law type. We suggest using a nonlinear Schr\\"odinger model with random potential on a lattice that quadratic nonlinearity plays a dynamically very distinguished role in that it is the only type of power nonlinearity permitting an abrupt localization-delocalization transition with unlimited spreading already at the delocalization border. For super-quadratic nonlinearity the borderline spreading corresponds to diffusion processes on finite clusters. We have proposed an analytical method to predict and explain such transport processes. Our method uses a topological approximation of the nonlinear Anderson model and, if the exponent of the power nonlinearity is either integer or half-integer, will yield the wanted value of the transport exponent via a triangulation procedure in an Euclidean mapping space. A kinetic picture of the transport arising from these investigations uses a fractional extension of the diffusion equation to fractional derivatives over the time, signifying non-Markovian dynamics with algebraically decaying time correlations.

A. V. Milovanov; A. Iomin

2014-05-29

210

Foundations of Physics, Vol . 28, No. 4, 1998 Bands of Localized Electromagnetic Waves in  

E-print Network

methods and concepts of solid-state physics. Let us mention, e.g., the concept of electron localization in investigations of Anderson localization in solid-state physics is to study the transport equa- tion

Rusek, Marian

211

Attosecond Photoscopy of Plasmonic Excitations  

NASA Astrophysics Data System (ADS)

We propose an experimental arrangement to image, with attosecond resolution, transient surface plasmonic excitations. The required modifications to state-of-the-art setups used for attosecond streaking experiments from solid surfaces only involve available technology. Buildup and lifetimes of surface plasmon polaritons can be extracted and local modulations of the exciting optical pulse can be diagnosed in situ.

Lupetti, Mattia; Hengster, Julia; Uphues, Thorsten; Scrinzi, Armin

2014-09-01

212

Attosecond photoscopy of plasmonic excitations.  

PubMed

We propose an experimental arrangement to image, with attosecond resolution, transient surface plasmonic excitations. The required modifications to state-of-the-art setups used for attosecond streaking experiments from solid surfaces only involve available technology. Buildup and lifetimes of surface plasmon polaritons can be extracted and local modulations of the exciting optical pulse can be diagnosed in situ. PMID:25259981

Lupetti, Mattia; Hengster, Julia; Uphues, Thorsten; Scrinzi, Armin

2014-09-12

213

Investigation of Anderson lattice behavior in Yb1-xLuxAl3  

SciTech Connect

Measurements of magnetic susceptibility {chi}(T), specific heat C(T), Hall coefficient R{sub H}(T), and Yb valence {nu} = 2 + n{sub f} [f-occupation number n{sub f} (T) determined from Yb L{sub 3} x-ray absorption measurements] were carried out on single crystals of Yb{sub 1-x}Lu{sub x}Al{sub 3}. The low temperature anomalies observed in {chi}(T) and C(T) corresponding to an energy scale T{sub coh} {approx} 40 K in the intermediate valence, Kondo lattice compound YbAl{sub 3} are suppressed by Lu concentrations as small as 5% suggesting these low-T anomalies are extremely sensitive to disorder and, therefore, are a true coherence effect. By comparing the temperature dependence of various physical quantities to the predictions of the Anderson Impurity Model, the slow crossover behavior observed in YbAl{sub 3}, in which the data evolve from a low-temperature coherent, Fermi-liquid regime to a high temperature local moment regime more gradually than predicted by the Anderson Impurity Model, appears to evolve to fast crossover behavior at x {approx} 0.7 where the evolution is more rapid than predicted. These two phenomena found in Yb{sub 1-x}Lu{sub x}Al{sub 3}, i.e., the low-T anomalies and the slow/fast crossover behavior are discussed in relation to recent theories of the Anderson lattice.

Bauer, E.D.; Booth, C.H.; Lawrence, J.M.; Hundley, M.F.; Sarrao, J.L.; Thompson, J.D.; Riseborough, P.S.; Ebihara, T.

2003-10-06

214

ANDERSON ACCELERATION FOR FIXED-POINT ITERATIONS HOMER F. WALKER AND PENG NI  

E-print Network

ANDERSON ACCELERATION FOR FIXED-POINT ITERATIONS HOMER F. WALKER AND PENG NI Abstract. This paper concerns an acceleration method for fixed-point iterations that originated in work of D. G. Anderson-560], which we accordingly call Anderson acceleration here. This method has enjoyed considerable success

Walker, Homer F.

215

Absence of spontaneous magnetization in low-dimensional Anderson and Kondo lattices  

E-print Network

L-635 Absence of spontaneous magnetization in low-dimensional Anderson and Kondo lattices C, at finite temperature, a one or two dimensional Anderson or Kondo lattice can have no spontaneous lattice Hamiltonians. In this paper we apply Bogoliubov's inequality to the Anderson and Kondo lattices and show

Boyer, Edmond

216

Luminescence and excitation line narrowing of [Ru(2,2script-bipyridine)3 - x (2,2script-bipyridine- d8)x]2 + (x=0-3) in [Zn(2,2script- bipyridine)3](CIO4)2. Unequivocal evidence for localized lowest-excited states  

NASA Astrophysics Data System (ADS)

Broadband and narrowed luminescence and excitation spectra at liquid helium temperatures of the title series (abbreviated as h24, d8, d16, and d24 for x=0, 1, 2, and 3, respectively) are reported. The luminescence spectra of the h24, d8, and d24 materials are found to be very similar except that the inhomogeneous broadening varies and a deuteration shift of 37 cm-1 to higher energy is observed for the d24 system. The luminescence of the d16 material is a superposition of the h24 and d24 spectra. Two distinct luminescence lifetimes can be measured in this material. The excitation spectra of the d8 and d16 materials are well represented as superpositions of the h24 and d24 spectra. The crystal structure establishes that there is only one spectroscopic site with two equivalent ligands. The third ligand has a different environment. The lowest-excited metal-to-ligand charge transfer states of the two equivalent ligands are localized on an electronic time scale but very fast intramolecular excitation energy transfer occurs.

Riesen, Hans; Krausz, Elmars

1993-11-01

217

Excite Assistant  

NSDL National Science Digital Library

Just when the concept of "push" technology seems like yesterday's news, Excite, Inc. produces a handy little program, the Excite Assistant, that pushes data to you without being pushy. The Excite Assistant provides you with instant access to various types of up-to-date information such as the weather for your area, the broadcast TV shows on at the moment, updated stock quotes, your horoscope, and more. The information is summarized within the Assistant's window, but when an item requires expansion, your browser is launched. By far the most useful aspect of this program is the mail notification feature. If you use Excite's Web-based mail service, the Excite Assistant, if active, will play a sound and it's icon will blink when new mail arrives. The Assistant will display the subject line and who the mail is from; clicking on the new mail loads it in your browser. Excite Assistant runs on Win95/98/NT and is free but does display small ads.

218

Neurological complications of Anderson-Fabry disease.  

PubMed

Characteristic clinical manifestations of AFD such as acroparesthesias, angiokeratoma, corneal opacity, hypo/ and anhidrosis, gastrointestinal symptoms, renal and cardiac dysfunctions can occur in male and female patients, although heterozygous females with AFD usually seem to be less severely affected. The most prominent CNS manifestations consist of cerebrovascular events such as transient ischaemic attacks (TIAs) and (recurrent) strokes. For the most part, CNS complications in AFD have been attributed to cerebral vasculopathy, including anatomical abnormalities. The natural history of Fabry patients includes transitory cerebral ischaemia and strokes, even in very young persons of both genders. The mechanism is partly due to vascular endothelial accumulation of Gb-3. White matter lesions (WML) on occur MRI. Both males and females can be safely treated with enzyme replacement; and thus screening for Fabry disease of young stroke populations should be considered. There are, however, no hard data of treatment effect on mortality and morbidity. Stroke in Anderson-Fabry disease study of 721 patients with cryptogenic stroke, aged 18-55 years, showed a high prevalence of Fabry disease in this group: 5% (21/432) of men and 3% (7/289) of women. Combining results of both sexes showed that 4% of young patients with stroke of previously unknown cause had Fabry disease, corresponding to about 1-2% of the general population of young stroke patients. Cerebral micro- and macro-vasculopathy have been described in Fabry disease. Neuronal globotriaosylceramide accumulation in selective cortical and brain stem areas including the hippocampus has been reported by autopsy studies in FD, but clinical surrogates as well as the clinical relevance of these findings have not been investigated so far. Another Neurologic hallmark of Fabry disease (FD) includes small fiber neuropathy as well as cerebral micro- and macroangiopathy with premature stroke. Cranial MRI shows progressive white matter lesions (WML) at an early age, increased signal intensity in the pulvinar, and tortuosity and dilatation of the larger vessels. Conventional MRI shows a progressive load of white matter lesions (WMLs) due to cerebral vasculopathy in the course of FD. Another study has been conducted to quantify brain structural changes in clinically affected male and female patients with FD. The peripheral neuropathy in Fabry disease manifests as neuropathic pain, reduced cold and warm sensation and possibly gastrointestinal disturbances. Patients with Fabry disease begin having pain towards the end of the first decade of life or during puberty. Children as young as 6 years of age have complained of pain often associated with febrile illnesses with reduced heat and exercise tolerance. The patients describe the pain as burning that is often associated with deep ache or paresthesiae. Some patients also have joint pain. A high proportion of patients with Fabry disease is at increased risk of developing neuropsychiatric symptoms, such as depression and neuropsychological deficits. Due to both somatic and psychological impairment, health-related quality of life (QoL) is considerably reduced in patients with Fabry disease. Targeted screening for Fabry disease among young individuals with stroke seems to disclose unrecognized cases and may therefore very well be recommended as routine in the future. Furthermore, ischemic stroke is related to inflammation and arterial stiffness and no study had addressed this relationship in patients with AF disease and cerebrovascular disease, so this topic could represent a possible future research line. PMID:23448452

Tuttolomondo, Antonino; Pecoraro, Rosaria; Simonetta, Irene; Miceli, Salvatore; Arnao, Valentina; Licata, Giuseppe; Pinto, Antonio

2013-01-01

219

VOLUME 89, NUMBER 4 P H Y S I C A L R E V I E W L E T T E R S 22 JULY 2002 Coherent X-Ray Raman Spectroscopy: A Nonlinear Local Probe for Electronic Excitations  

E-print Network

of coherent Raman spectroscopy provide an excellent real-space probe that carries most valuable structural Spectroscopy: A Nonlinear Local Probe for Electronic Excitations Satoshi Tanaka1,3 and Shaul Mukamel1,2 1-ray frequencies across the valence excitations, it is possible to probe the entire manifold of molecular

Mukamel, Shaul

220

Strategies in localization proofs for one-dimensional random Schrödinger operators  

Microsoft Academic Search

Recent results on localization, both exponential and dynamical, for various models of one-dimensional, continuum, random Schr¨ odinger operators are reviewed. This includes Anderson models with indefinite single site potentials, the Bernoulli- Anderson model, the Poisson model, and the random displacement model. Among the tools which are used to analyse these models are generalized spectral averaging tech- niques and results from

UNTER STOLZ

2002-01-01

221

Plant and Animal Sciences Val J. Anderson, Chair  

E-print Network

Plant and Animal Sciences Val J. Anderson, Chair 275 WIDB, (801) 422-3527 College of Biology programs in the Department of Plant and Animal Sciences are open enrollment. The Discipline Disciplines in the Department of Plant and Animal Sciences focus on four of the great dilemmas facing mankind in the twenty

Hart, Gus

222

POLAR SEA ICE MAPPING FOR SEAWINDS Hyrum S. Anderson  

E-print Network

POLAR SEA ICE MAPPING FOR SEAWINDS by Hyrum S. Anderson A thesis submitted to the faculty, College of Engineering and Technology #12;viii #12;ABSTRACT POLAR SEA ICE MAPPING FOR SEAWINDS Hyrum S sea ice. Advances in microwave remote sensing technology have allowed a large-scale and detailed study

Long, David G.

223

Elizabeth Garrett Anderson and the professionalism of medical publicity  

Microsoft Academic Search

A B S T R A C T • This article examines how early women doctors managed their professional and public images in the second half of the nineteenth century through a case study of the career of the first medical woman to qualify in Britain: Elizabeth Garrett Anderson (1836—1917). In fighting for their cause, Victorian women doctors had to

Claire Brock

2008-01-01

224

Nuclear liability and the Price--Anderson Act  

Microsoft Academic Search

The Price-Anderson Act is viewed as meeting public needs in a unique and responsible way, reflecting the far-sightedness of those involved in the early development of nuclear power who saw the importance of building safety into each step of the program. An extension of the Act is advised as a first step in recognizing that many potential and real disasters

2009-01-01

225

SUBSIDY TO NUCLEAR POWER THROUGH PRICE-ANDERSON LIABILITY LIMIT  

Microsoft Academic Search

Between 1959 and 1982, the Price-Anderson Act placed a limit of $560 million on the liability of nuclear power plant operators for accidental damages. This limit grew to $7 billion due to the 1988 amendments to the act. This paper using insurance premiums charged for the first $160 million of coverage and the Nuclear Regulatory Commission's estimate of the probability

JEFFREY A. DUBIN; GEOFFREY S. ROTHWELL

1990-01-01

226

Anderson-Fabry cardiomyopathy: prevalence, pathophysiology, diagnosis and treatment.  

PubMed

Anderson-Fabry disease (AFD) is a lysosomal storage disease caused by the inappropriate accumulation of globotriaosylceramide in tissues due to a deficiency in the enzyme ?-galactosidase A (?-Gal A). Anderson-Fabry cardiomyopathy is characterized by structural, valvular, vascular and conduction abnormalities, and is now the most common cause of mortality in patients with AFD. Large-scale metabolic and genetic screening studies have revealed AFD to be prevalent in populations of diverse ethnic origins, and the variant form of AFD represents an unrecognized health burden. Anderson-Fabry disease is an X-linked disorder, and genetic testing is critical for the diagnosis of AFD in women. Echocardiography with strain imaging and cardiac magnetic resonance imaging using late enhancement and T1 mapping are important imaging tools. The current therapy for AFD is enzyme replacement therapy (ERT), which can reverse or prevent AFD progression, while gene therapy and the use of molecular chaperones represent promising novel therapies for AFD. Anderson-Fabry cardiomyopathy is an important and potentially reversible cause of heart failure that involves LVH, increased susceptibility to arrhythmias and valvular regurgitation. Genetic testing and cardiac MRI are important diagnostic tools, and AFD cardiomyopathy is treatable if ERT is introduced early. PMID:25030479

Putko, Brendan N; Wen, Kevin; Thompson, Richard B; Mullen, John; Shanks, Miriam; Yogasundaram, Haran; Sergi, Consolato; Oudit, Gavin Y

2014-07-17

227

Microdissection: a tool for bee chromosome studies Anderson FERNANDES  

E-print Network

Microdissection: a tool for bee chromosome studies Anderson FERNANDES 1,2 , Patrícia Elda Sobrinho a microdissection protocol for cytogenetic studies in bees. This methodology was first used in these insects and may chromosomes and others. For this study, the centromeric region of chromosomes in the stingless bee

228

Augmenting Depth Camera Output Using Photometric Stereo Robert Anderson  

E-print Network

containing the high frequency information of a normal map and the low frequency information from a depth mapAugmenting Depth Camera Output Using Photometric Stereo Robert Anderson Department of Engineering Department of Engineering University of Cambridge Abstract We present a system for augmenting depth cam- era

Martin, Ralph R.

229

A Genetic Algorithm for Grammars James Anderson and Joe Staines  

E-print Network

A Genetic Algorithm for Grammars James Anderson and Joe Staines July 1, 2010 Background training data. 1 #12;A Genetic Algorithm for Grammars Of course, there are many more grammars than be able to search heuristically. Project Proposal We propose a project which uses a genetic algorithm

Goldschmidt, Christina

230

Measuring the Cost of Cybercrime Ross Anderson 1  

E-print Network

Measuring the Cost of Cybercrime Ross Anderson 1 Chris Barton 2 Rainer B¨ohme 3 Richard Clayton 4 what we believe to be the first systematic study of the costs of cybercrime. It was prepared the problem. For each of the main categories of cybercrime we set out what is and is not known of the direct

Savage, Stefan

231

Atomic Semantics of Nonatomic James H. Anderson Mohamed G. Gouda  

E-print Network

Atomic Semantics of Nonatomic Programs James H. Anderson Mohamed G. Gouda Department of Computer that it is possible, and sometimes useful, to reason about nonatomic programs within the conventional atomic model concurrent programs are developed within the atomic model of concurrency Ho 72, LS 84, MP 84, OG 76

Anderson, James

232

Solving a puzzle in the Anderson transition with long-range correlated potentials  

NASA Astrophysics Data System (ADS)

The conditions for an Anderson transition in 1D systems has been an open question since it's discovery a half century ago. Although scaling theory predicts localization in this case, it has been shown that a transition exists in the presence of some form of long-range correlations in the on-site energies. One of the most widely used examples are disorder potentials generated by 1/k^? spectral densities [1] that, with an appropriate short range cutoff, result in vanishing correlation functions in the thermodynamic limit. However, these results are in direct contradiction to work by Kotani et. al. [2] that argues for the existence of a metallic state only when infinite range correlations are non-zero. In this talk we will show that there is no contradiction between the two results as the correlation function generated from numerical techniques is staunchly different from analytic expectations. Furthermore, we will present the exact analytic expression for the correlation function in the thermodynamic limit. Finally, we will discuss the role played by short- and long-range features of the correlation function in the Anderson transition. [4pt] [1] F. Moura and M. Lyra, PRL 81, 3735 (1998)[0pt] [2] S. Kotani and B. Simon Commun. Math. Phys. 112,103 (1985).

Petersen, Greg; Sandler, Nancy

2013-03-01

233

Effective cluster typical medium theory for the diagonal Anderson disorder model in one- and two-dimensions.  

PubMed

We develop a cluster typical medium theory to study localization in disordered electronic systems. Our formalism is able to incorporate non-local correlations beyond the local typical medium theory in a systematic way. The cluster typical medium theory utilizes the momentum-resolved typical density of states and hybridization function to characterize the localization transition. We apply the formalism to the Anderson model of localization in one- and two-dimensions. In one-dimension, we find that the critical disorder strength scales inversely with the linear cluster size with a power law, Wc ? (1/Lc)(1/?), whereas in two-dimensions, the critical disorder strength decreases logarithmically with the linear cluster size. Our results are consistent with previous numerical work and are in agreement with the one-parameter scaling theory. PMID:24934293

Ekuma, Chinedu E; Terletska, Hanna; Meng, Zi Yang; Moreno, Juana; Jarrell, Mark; Mahmoudian, Samiyeh; Dobrosavljevi?, Vladimir

2014-07-01

234

Excited Insects  

E-print Network

but not killing them doesn't actually count as true celebration. Now, China. There's a country that knows how to make a bug feel good. Bugs have their very own holiday in the Chinese calendar. It's called the Feast of the Excited Insects and it falls on March 5th...

Hacker, Randi

2011-04-06

235

Interorbital interaction in the one-dimensional periodic Anderson model: Density matrix renormalization group study  

NASA Astrophysics Data System (ADS)

We investigate the effect of the Coulomb interaction, Ucf, between the conduction and f electrons in the periodic Anderson model using the density matrix renormalization group algorithm. We calculate the excitation spectrum of the half-filled symmetric model with an emphasis on the spin and charge excitations. In the one-dimensional version of the model, it is found that the spin gap is smaller than the charge gap below a certain value of Ucf and the reversed inequality is valid for stronger Ucf. This behavior is also verified by the behavior of the spin and density correlation functions. We also perform a quantum information analysis of the model and determine the entanglement map of the f and conduction electrons. It is revealed that for a certain Ucf the ground state is dominated by the configuration in which the conduction and f electrons are strongly entangled, and the ground state is almost a product state. For larger Ucf, the sites are occupied alternatingly dominantly by two f electrons or by two conduction electrons.

Hagymási, I.; Sólyom, J.; Legeza, Ö.

2014-09-01

236

Paleontological analysis of a lacustrine carbonaceous uranium deposit at the Anderson mine, Date Creek basin, west-central Arizona (U.S.A.)  

USGS Publications Warehouse

The Tertiary sedimentary sequence of the Date Creek basin area of Arizona is composed principally of intertonguing alluvial-fan and lacustrine deposits. The lacustrine rocks contain large intermediate- to, locally, high-grade uranium deposits that form one of the largest uranium resources in the United States (an estimated 670,000 tons of U3O8 at an average grade of 0.023% is indicated by drilling to date). At the Anderson mine, about 50,000 tons of U3O8 occurs in lacustrine carbonaceous siltstones and mudstones (using a cutoff grade of 0.01%). The Anderson mine constitutes a new class of ore deposit, a lacustrine carbonaceous uranium deposit. Floral and faunal remains at the Anderson mine played a critical role in creating and documenting conditions necessary for uranium mineralization. Organic-rich, uraniferous rocks at the Anderson mine contain plant remains and ostracodes having remarkably detailed preservation of internal features because of infilling by opaline silica. This preservation suggests that the alkaline lake waters in the mine area contained high concentrations of dissolved silica and that silicification occurred rapidly, before compaction or cementation of the enclosing sediment. Uranium coprecipitated with the silica. Thinly laminated, dark-colored, siliceous beds contain centric diatoms preserved with carbonaceous material suggesting that lake waters at the mine were locally deep and anoxic. These alkaline, silica-charged waters and a stagnant, anoxic environment in parts of the lake were necessary conditions for the precipitation of large amounts of uranium in the lake-bottom sediments. Sediments at the Anderson mine contain plant remains and pollen that were derived from diverse vegetative zones suggesting about 1500 m of relief in the area at the time of deposition. The pollen suggests that the valley floor was semiarid and subtropical, whereas nearby mountains supported temperate deciduous forests. ?? 1990.

Otton, J.K.; Bradbury, J.P.; Forester, R.M.; Hanley, J.H.

1990-01-01

237

Topologically invariant tensor renormalization group method for the Edwards-Anderson spin glasses model  

NASA Astrophysics Data System (ADS)

Tensor renormalization group (TRG) method is a real space renormalization group approach. It has been successfully applied to both classical and quantum systems. In this paper, we study a disordered and frustrated system, the two-dimensional Edwards-Anderson model, by a new topological invariant TRG scheme. We propose an approach to calculate the local magnetizations and nearest pair correlations simultaneously. The Nishimori multicritical point predicted by the topological invariant TRG agrees well with the recent Monte Carlo results. The TRG schemes outperform the mean-field methods on the calculation of the partition function. We notice that it might obtain a negative partition function at sufficiently low temperatures. However, the negative contribution can be neglected if the system is large enough. This topological invariant TRG can also be used to study three-dimensional spin glass systems.

Wang, Chuang; Qin, Shao-Meng; Zhou, Hai-Jun

2014-11-01

238

Critical Metal Phase at the Anderson Metal-Insulator Transition with Kondo Impurities  

NASA Astrophysics Data System (ADS)

It is well known that magnetic impurities can change the symmetry class of disordered metallic systems by breaking spin and time-reversal symmetry. At low temperature, these symmetries can be restored by Kondo screening. It is also known that at the Anderson metal-insulator transition, wave functions develop multifractal fluctuations with power-law correlations. Here, we consider the interplay of these two effects. We show that multifractal correlations open local pseudogaps at the Fermi energy at some random positions in space. When dilute magnetic impurities are at these locations, Kondo screening is strongly suppressed. When the exchange coupling J is smaller than a certain value J*, the metal-insulator transition point extends to a critical region in the disorder strength parameter and to a band of critical states.

Kettemann, S.; Mucciolo, E. R.; Varga, I.

2009-09-01

239

Critical metal phase at the Anderson metal-insulator transition with Kondo impurities  

NASA Astrophysics Data System (ADS)

It is well known that magnetic impurities can change the symmetry class of disordered metallic systems by breaking spin and time-reversal symmetry. At low temperature, these symmetries can be restored by Kondo screening. It is also known that at the Anderson metal-insulator transition, wave functions develop multifractal fluctuations with power-law correlations. Here, we consider the interplay of these two effects. We show that multifractal correlations open local pseudogaps at the Fermi energy at some random positions in space. When dilute magnetic impurities are at these locations, Kondo screening is strongly suppressed. When the exchange coupling J is smaller than a certain value J^*, the metal-insulator transition point extends to a critical region in the disorder strength parameter and to a band of critical states. The width of this critical region increases with a power of the concentration of magnetic impurities. [S. Kettemann, E. R. Mucciolo, and I. Varga, Phys. Rev. Lett. 103, 126401 (2009).

Mucciolo, Eduardo; Kettemann, Stefan; Varga, Imre

2010-03-01

240

Amour des langues/amour de la langue Patrick Anderson  

E-print Network

Amour des langues/amour de la langue Patrick Anderson Professeur des universités UFR SLHS français dans le monde, Recherches et applications, n° 45, 2009. #12;De la disparition.... Parler d'amour des langues et d'amour de la langue, à première vue, ne concerne pas l'enseignement des langues, parce

Jeanjean, Louis

241

UT MD Anderson scientists discover secret life of chromatin:  

Cancer.gov

Chromatin--the intertwined histone proteins and DNA that make up chromosomes--constantly receives messages that pour in from a cell’s intricate signaling networks... But chromatin also talks back, scientists at The University of Texas M.D. Anderson Cancer Center report today in the journal Cell, issuing orders affecting a protein that has nothing to do with chromatin’s central role in gene transcription--the first step in protein formation.

242

Solar hot water system installed at Anderson, South Carolina  

NASA Technical Reports Server (NTRS)

A description is given of the solar energy hot water system installed in the Days Inns of America, Inc., at Anderson, South Carolina. The building is a low-rise, two-story 114-room motel. The solar system was designed to provide 40 percent of the total hot water demand. The collector is a flat plate, liquid with an area of 750 square feet. Operation of this system was begun in November 1977, and has performed flawlessly for one year.

1978-01-01

243

Moments and Lyapunov exponents for the parabolic Anderson model  

E-print Network

We study the parabolic Anderson model in $(1+1)$ dimensions with nearest neighbor jumps and space-time white noise (discrete space/continuous time). We prove a contour integral formula for the second moment and compute the second moment Lyapunov exponent. For the model with only jumps to the right, we prove a contour integral formula for all moments and compute moment Lyapunov exponents of all orders.

Alexei Borodin; Ivan Corwin

2014-04-28

244

Anderson and Belnap’s Invitation to Sin  

Microsoft Academic Search

Quine has argued that modal logic began with the sin of confusing use and mention. Anderson and Belnap, on the other hand,\\u000a have offered us a way out through a strategy of nominalization. This paper reviews the history of Lewis’s early work in modal\\u000a logic, and then proves some results about the system in which “A is necessary” is intepreted

Alasdair Urquhart

2010-01-01

245

MD Anderson researchers find coupling of proteins promotes glioblastoma development:  

Cancer.gov

Two previously unassociated proteins known to be overly active in a variety of cancers bind together to ignite and sustain malignant brain tumors, a research team led by scientists at The University of Texas MD Anderson Cancer Center reports this week in the journal Cancer Cell. This research is the first to connect FoxM1 to a molecular signaling cascade that regulates normal neural stem cells...

246

Topological Anderson insulator induced by inter-cell hopping disorder  

SciTech Connect

We have studied in detail the influence of same-orbit and different-orbit hopping disorders in HgTe/CdTe quantum wells. Intriguingly, similar to the behavior of the on-site Anderson disorder, a phase transition from a topologically trivial phase to a topological phase is induced at a proper strength of the same-orbit hopping disorder. For different-orbit hopping disorder, however, the phase transition does not occur. The results have been analytically verified by using effective medium theory. A consistent conclusion can be obtained by comparing phase diagrams, conductance, and conductance fluctuations. In addition, the influence of Rashba spin-orbit interaction (RSOI) on the system has been studied for different types of disorder, and the RSOI shows different influence on topological phase at different disorders. The topological phase induced by same-orbit hopping disorder is more robust against the RSOI than that induced by on-site Anderson disorder. For different-orbit hopping disorder, no matter whether the RSOI is included or not, the phase transition does not occur. The results indicate, whether or not the topological Anderson insulator can be observed depends on a competition between the different types of the disorder as well as the strength of the RSOI in a system.

Lv, Shu-Hui [Hebei Advanced Thin Film Laboratory, College of Physics, Hebei Normal University, Hebei 050024 (China); College of Sciences, Hebei University of Science and Technology, Shijiazhuang 050018 (China); Song, Juntao, E-mail: jtsong@mail.hebtu.edu.cn; Li, Yu-Xian, E-mail: yxli@mail.hebtu.edu.cn [Hebei Advanced Thin Film Laboratory, College of Physics, Hebei Normal University, Hebei 050024 (China)

2013-11-14

247

Effects of correlated hybridization in the single-impurity Anderson model  

NASA Astrophysics Data System (ADS)

The development of new materials often dependents on the theoretical foundations which study the microscopic matter, i.e., the way atoms interact and create distinct configurations. Among the interesting materials, those with partially filled d or f orbitals immersed in nonmagnetic metals have been described by the Anderson model, which takes into account Coulomb correlation (U) when a local level (energy Ed) is doubled occupied, and an electronic hybridization between local levels and conduction band states. In addition, here we include a correlated hybridization term, which depends on the local-level occupation number involved. This term breaks particle-hole symmetry (even when U+2Ed=0), enhances charge fluctuations on local levels and as a consequence strongly modifies the crossover between the Hamiltonian fixed-points, even suppressing one or other. We exemplify these behaviors showing data obtained from the Numerical Renormalization Group (NRG) computation for the impurity temperature-dependent specific heat, entropy and magnetic susceptibility. The interleaving procedure is used to recover the continuum spectrum after the NRG-logarithmic discretization of the conduction band.

Líbero, Valter; Veiga, Rodrigo

2013-03-01

248

Spin-dependent localized Hartree-Fock density-functional approach for the accurate treatment of inner-shell excitation of closed-shell atoms  

E-print Network

energies #1;#1;E#2; of inner-shell excited states 1s?1np 1,3P #1;n=2#5;8#2; of B+. The ground- state energy is ?24.3284 #1;a.u.#2;. States ?E #1;a.u.#2; Present worka #1;E #1;eV#2; Present worka Other theoryb Expt.c 1s?12p 3P 17.2559 192.4546 192.460 1P 17... worka Other theoryb 2s?13p 3P 196.6721 92.5820 91.72 1P 196.6630 92.8288 2s?14p 3P 196.5181 96.7718 96.18 1P 196.5170 96.8026 2s?15p 3P 196.4871 97.6164 97.11 1P 196.4865 97.6317 2s?16p 3P 196.4738 97.9775 1P 196.4735 97.9863 2s?17p 3P 196.4669 98.1667 1...

Chu, Shih-I; Zhou, Zhongyuan

2007-01-17

249

Ground and excited states of group IVA diatomics from local-spin-density calculations: Model potentials for Si, Ge, and Sn  

NASA Astrophysics Data System (ADS)

LCGTO-MP-LSD results are reported for the spectroscopic constants and electronic structure of the diatomic molecules Si2, Ge2, Sn2, SiGe, SiSn, and GeSn in their low-lying electronic states. For the homonuclear molecules we found that the ground state is 3?-g with the most important lower-lying excited states being 3?u, 1?u, and 1?+g, respectively. Our results are in good agreement with the available experimental data and also in qualitative agreement with other theoretical studies. We present here the first theoretical study on the heteronuclear molecules, for which experimental data are not available. We found the 3?- state to be the lowest, followed by 3? and 1?+ states. Model potentials (MP) are reported for the Si, Ge, and Sn atoms. The reliable results for molecules complement those for the atoms and show that the LSD model potentials presented here allow for an accurate description of chemical bonding and spectroscopic properties in the title molecules.

Andzelm, Jan; Russo, Nino; Salahub, Dennis R.

1987-12-01

250

Astronaut Clay Anderson Speaks With S.C. Students - Duration: 25:29.  

NASA Video Gallery

From NASA's International Space Station Mission Control Center, NASA astronaut Clay Anderson participates in a Digital Learning Network (DLN) event with students at Crayton Middle School, Columbia,...

251

Single-site and cellular dynamical mean-field theory of the Anderson-Hubbard model  

NASA Astrophysics Data System (ADS)

We study the Anderson-Hubbard model to examine the interplay between the disordered potential and the Hubbard interactions. We use the dynamical mean-field theory (DMFT) with an exact diagonalization as an impurity solver to effectively deal with the quantum fluctuations due to the local interactions. In order to characterize the paramagnetic metal-insulator transition in disordered systems, we compute the typical local density of states, as well as the arithmetically-averaged local density of states. Our approach is found to reproduce the characteristic features of the metal-insulator transition in infinite dimensions, such as the existence of the disorder-driven metallic phase for moderate values of disorder strength and interactions, as observed in earlier studies. In two dimensions, the system turns out to exhibit more insulating behavior when we increase the cluster size in the cellular DMFT. The metallic phase, which is induced from weak Mott insulators by the introduction of a disordered potential, is not observed in two dimensions.

Go, Ara; Jeon, Gun Sang

2013-03-01

252

Dynamical Localization in Kicked Quantum Rotors  

E-print Network

The periodically $\\delta$-kicked quantum linear rotor is known to experience non-classical bounded energy growth due to quantum dynamical localization in angular momentum space. We study the effect of random deviations of the kick period in simulations and experiments. This breaks the energy and angular momentum localization and increases the rotational alignment, which is the analog of the onset of Anderson localization in 1-D chains.

Kamalov, Andrei; Bucksbaum, Philip H

2015-01-01

253

Price-Anderson Nuclear Safety Enforcement Program. 1996 Annual report  

SciTech Connect

This first annual report on DOE`s Price Anderson Amendments Act enforcement program covers the activities, accomplishments, and planning for calendar year 1996. It also includes the infrastructure development activities of 1995. It encompasses the activities of the headquarters` Office of Enforcement in the Office of Environment, Safety and Health (EH) and Investigation and the coordinators and technical advisors in DOE`s Field and Program Offices and other EH Offices. This report includes an overview of the enforcement program; noncompliances, investigations, and enforcement actions; summary of significant enforcement actions; examples where enforcement action was deferred; and changes and improvements to the program.

NONE

1996-01-01

254

Many-body localization nonlinear transport  

E-print Network

. L. Altshuler Columbia University #12;Outline · Introduction: dc conduction in Anderson insulators at low temperatures · Effect of electron-electron interaction: finite-T metal-insulator transition electrons in a random potential extended localized mobility edge Fermi level thermal population of extended

Fominov, Yakov

255

Pannexin 1 channels link chemoattractant receptor signaling to local excitation and global inhibition responses at the front and back of polarized neutrophils.  

PubMed

Neutrophil chemotaxis requires excitatory signals at the front and inhibitory signals at the back of cells, which regulate cell migration in a chemotactic gradient field. We have previously shown that ATP release via pannexin 1 (PANX1) channels and autocrine stimulation of P2Y2 receptors contribute to the excitatory signals at the front. Here we show that PANX1 also contributes to the inhibitory signals at the back, namely by providing the ligand for A2A adenosine receptors. In resting neutrophils, we found that A2A receptors are uniformly distributed across the cell surface. In polarized cells, A2A receptors redistributed to the back where their stimulation triggered intracellular cAMP accumulation and protein kinase A (PKA) activation, which blocked chemoattractant receptor signaling. Inhibition of PANX1 blocked A2A receptor stimulation and cAMP accumulation in response to formyl peptide receptor stimulation. Treatments that blocked endogenous A2A receptor signaling impaired the polarization and migration of neutrophils in a chemotactic gradient field and resulted in enhanced ERK and p38 MAPK signaling in response to formyl peptide receptor stimulation. These findings suggest that chemoattractant receptors require PANX1 to trigger excitatory and inhibitory signals that synergize to fine-tune chemotactic responses at the front and back of neutrophils. PANX1 channels thus link local excitatory signals to the global inhibitory signals that orchestrate chemotaxis of neutrophils in gradient fields. PMID:23798685

Bao, Yi; Chen, Yu; Ledderose, Carola; Li, Linglin; Junger, Wolfgang G

2013-08-01

256

No strangers here: The minimal relationship effect in interpersonal trust Joanna E. Anderson1  

E-print Network

of one's trust in, or feeling of security with, the other person (Holmes & Anderson, 2009). TrustNo strangers here: The minimal relationship effect in interpersonal trust Joanna E. Anderson1 Laboratory games reveal that people trust strangers in spite of an overall cynicism about others

257

Between a metal and an insulator: the critical state of the Anderson transition Gabriel Lemarie,1,  

E-print Network

Between a metal and an insulator: the critical state of the Anderson transition Gabriel Lemari´e,1 experimentally realized with a cold atomic gas, we study the transport properties at the critical point of the metal-insulator Anderson transi- tion. We accurately measure the time-evolution of an initially

Paris-Sud XI, Université de

258

James Anderson's Political Economy--His Influence on Smith and Malthus  

Microsoft Academic Search

James Anderson's powerful critique of Adam Smith's position on the corn export bounty was published in 1777. It focuse d on Smith's proposition that the bounty could not lead to increased corn production because it could not increase corn's real price. Smit h's response to the critique is traced in later editions of Wealth of Nations. While Anderson's critique of

Renee Prendergast

1987-01-01

259

Concurrent RealTime Music in C++ David P. Anderson yz  

E-print Network

. Layer three provides pitches, scales, notes, rhythm specification, and higher­level musical abstractions pitches, notes, scales, rhythms, and higher­level musical abstractions. Figure 1 shows the MOOD classConcurrent Real­Time Music in C++ David P. Anderson yz !anderson@snow.berkeley.edu? Jeff Bilmes y

Bilmes, Jeff

260

78 FR 41835 - Inflation Adjustments to the Price-Anderson Act Financial Protection Regulations  

Federal Register 2010, 2011, 2012, 2013, 2014

...NRC-2013-0072] RIN 3150-AJ25 Inflation Adjustments to the Price-Anderson Act...specified in the Price-Anderson Act for inflation at least once during each 5-year period...70 FR 61885), and the first periodic inflation adjustments on September 29,...

2013-07-12

261

Comment on Anderson and Cuneo's "The Height + Width Rule in Children's Judgments of Quantity."  

ERIC Educational Resources Information Center

Bogartz questions the Anderson and Cuneo study (p335-78 of this issue) on statistical-methodological grounds and on their positions concerning the concepts of conservation, centration, and compensation. (For Anderson and Cuneo's rejoinder to Bogartz, see p388-92 of this journal issue.) (SJL)

Bogartz, Richard S.

1978-01-01

262

Renormalized perturbation theory flow equations for the Anderson impurity model  

NASA Astrophysics Data System (ADS)

We apply the renormalized perturbation theory (RPT) to the symmetric Anderson impurity model. Within the RPT framework exact results for physical observables such as the spin and charge susceptibility can be obtained in terms of the renormalized values of the hybridization ? and Coulomb interaction U of the model. The main difficulty in the RPT approach usually lies in the calculation of the renormalized values themselves. In the present work we show how this can be accomplished by deriving differential flow equations describing the evolution of with ?. By exploiting the fact that can be determined analytically in the limit ? ? ? we solve the flow equations numerically to obtain estimates for the renormalized parameters in the range 0 < U/ ??< 3.5.

Pandis, Vassilis

2014-11-01

263

Price-Anderson Nuclear Safety Enforcement Program. 1997 annual report  

SciTech Connect

This report summarizes activities in the Department of Energy's Price-Anderson Amendments Act (PAAA) Enforcement Program in calendar year 1997 and highlights improvements planned for 1998. The DOE Enforcement Program involves the Office of Enforcement and Investigation in the DOE Headquarters Office of Environment, Safety and Health, as well as numerous PAAA Coordinators and technical advisors in DOE Field and Program Offices. The DOE Enforcement Program issued 13 Notices of Violation (NOV`s) in 1997 for cases involving significant or potentially significant nuclear safety violations. Six of these included civil penalties totaling $440,000. Highlights of these actions include: (1) Brookhaven National Laboratory Radiological Control Violations / Associated Universities, Inc.; (2) Bioassay Program Violations at Mound / EG and G, Inc.; (3) Savannah River Crane Operator Uptake / Westinghouse Savannah River Company; (4) Waste Calciner Worker Uptake / Lockheed-Martin Idaho Technologies Company; and (5) Reactor Scram and Records Destruction at Sandia / Sandia Corporation (Lockheed-Martin).

NONE

1998-01-01

264

Kondo destruction and valence fluctuations in an Anderson model.  

PubMed

Unconventional quantum criticality in heavy-fermion systems has been extensively analyzed in terms of a critical destruction of the Kondo effect. Motivated by a recent demonstration of quantum criticality in a mixed-valent heavy-fermion system, ?-YbAlB(4), we study a particle-hole-asymmetric Anderson impurity model with a pseudogapped density of states. We demonstrate Kondo destruction at a mixed-valent quantum critical point, where a collapsing Kondo energy scale is accompanied by a singular charge-fluctuation spectrum. Both spin and charge responses scale with energy over temperature (?/T) and magnetic field over temperature (H/T). Implications for unconventional quantum criticality in mixed-valence heavy fermions are discussed. PMID:23002763

Pixley, J H; Kirchner, Stefan; Ingersent, Kevin; Si, Qimiao

2012-08-24

265

Some comments on Anderson and Pospahala's correction of bias in line transect sampling  

USGS Publications Warehouse

ANDERSON and POSPAHALA (1970) investigated the estimation of wildlife population size using the belt or line transect sampling method and devised a correction for bias, thus leading to an estimator with interesting characteristics. This work was given a uniform mathematical framework in BURNHAM and ANDERSON (1976). In this paper we show that the ANDERSON-POSPAHALA estimator is optimal in the sense of being the (unique) best linear unbiased estimator within the class of estimators which are linear combinations of cell frequencies, provided certain assumptions are met.

Anderson, D.R.; Burnham, K.P.; Chain, B.R.

1980-01-01

266

Strategies in localization proofs for one-dimensional random Schrödinger operators  

Microsoft Academic Search

Recent results on localization, both exponential and dynamical, for various models of one-dimensional, continuum, random Schrödinger\\u000a operators are reviewed. This includes Anderson models with indefinite single site potentials, the BernoulliAnderson model,\\u000a the Poisson model, and the random displacement model. Among the tools which are used to analyse these models are generalized\\u000a spectral averaging techniques and results from inverse spectral and

Günter Stolz

2002-01-01

267

Elementary excitations and crossover phenomenon in liquids.  

PubMed

The elementary excitations of vibration in solids are phonons. But in liquids phonons are extremely short lived and marginalized. In this Letter through classical and ab initio molecular dynamics simulations of the liquid state of various metallic systems we show that different excitations, the local configurational excitations in the atomic connectivity network, are the elementary excitations in high temperature metallic liquids. We also demonstrate that the competition between the configurational excitations and phonons determines the so-called crossover phenomenon in liquids. These discoveries open the way to the explanation of various complex phenomena in liquids, such as fragility and the rapid increase in viscosity toward the glass transition, in terms of these excitations. PMID:25167427

Iwashita, T; Nicholson, D M; Egami, T

2013-05-17

268

Elementary Excitations and Crossover Phenomenon in Liquids  

NASA Astrophysics Data System (ADS)

The elementary excitations of vibration in solids are phonons. But in liquids phonons are extremely short lived and marginalized. In this Letter through classical and ab initio molecular dynamics simulations of the liquid state of various metallic systems we show that different excitations, the local configurational excitations in the atomic connectivity network, are the elementary excitations in high temperature metallic liquids. We also demonstrate that the competition between the configurational excitations and phonons determines the so-called crossover phenomenon in liquids. These discoveries open the way to the explanation of various complex phenomena in liquids, such as fragility and the rapid increase in viscosity toward the glass transition, in terms of these excitations.

Iwashita, T.; Nicholson, D. M.; Egami, T.

2013-05-01

269

A new dataset of Wood Anderson magnitude from the Trieste (Italy) seismic station  

NASA Astrophysics Data System (ADS)

The standard torsion Wood Anderson (WA) seismograph owes its fame to the fact that historically it has been used for the definition of the magnitude of an earthquake (Richter, 1935). With the progress of the technology, digital broadband (BB) seismographs replaced it. However, for historical consistency and homogeneity with the old seismic catalogues, it is still important continuing to compute the so called Wood Anderson magnitude. In order to evaluate WA magnitude, the synthetic seismograms WA equivalent are simulated convolving the waveforms recorded by a BB instrument with a suitable transfer function. The value of static magnification that should be applied in order to simulate correctly the WA instrument is debated. The original WA instrument in Trieste operated from 1971 to 1992 and the WA magnitude (MAW) estimates were regularly reported in the seismic station bulletins. The calculation of the local magnitude was performed following the Richter's formula (Richter, 1935), using the table of corrections factor unmodified from those calibrated for California and without station correction applied (Finetti, 1972). However, the WA amplitudes were computed as vector sum rather than arithmetic average of the horizontal components, resulting in a systematic overestimation of approximately 0.25, depending on the azimuth. In this work, we have retrieved the E-W and N-S components of the original recordings and re-computed MAW according to the original Richter (1935) formula. In 1992, the WA recording were stopped, due to the long time required for the daily development of the photographic paper, the costs of the photographic paper and the progress of the technology. After a decade of interruption, the WA was recovered and modernized by replacing the recording on photographic paper with an electronic device and it continues presently to record earthquakes. The E-W and N-S components records were memorized, but not published till now. Since 2004, next to the WA (few decimeters apart), a Guralp 40-T BB seismometer was installed, with a proper period extended to 60 s. Aim of the present work is twofold: from one side to recover the whole data set of MAW values recorded from 1971 until now, with the correct estimate of magnitude, and from the other side to verify the WA static magnification, comparing the real WA data with the ones simulated from broadband seismometer recordings.

Sandron, Denis; Gentile, G. Francesco; Gentili, Stefania; Rebez, Alessandro; Santulin, Marco; Slejko, Dario

2014-05-01

270

MD Anderson study explains high platelets in ovarian cancer patients; survival reduced  

Cancer.gov

Highly elevated platelet levels fuel tumor growth and reduce the survival of ovarian cancer patients, an international team of researchers led by scientists at The University of Texas MD Anderson Cancer center reports in the New England Journal of Medicine.

271

Multipactor experiment on a dielectric surface R. B. Anderson, W. D. Getty,a)  

E-print Network

Multipactor experiment on a dielectric surface R. B. Anderson, W. D. Getty,a) M. L. Brake, Y. Y of excessive noise in communication sat- ellites, detuning of resonant cavities, and increased outgas- sing

Valfells, Ágúst

272

A guide to source materials of the life and work of Lawrence B. Anderson '30  

E-print Network

From 1933 to 1976, Professor Lawrence B. Anderson taught in the MIT Department of Architecture, and from 1947 to 1971, he served as its chairman and dean. Concurrently, from 1937 to 1972 , he was principal partner in the ...

Laguette, Victoria, 1953-

1998-01-01

273

MD Anderson studies find proton therapy treatment preserves quality of life for men with prostate cancer  

Cancer.gov

Two studies led by The University of Texas MD Anderson Cancer Center have found that proton therapy preserves the quality of life, specifically urinary and bowel function, in men treated with this targeted radiation modality for prostate cancer.

274

MD Anderson researchers find that cancer cells adapt energy needs to spread illness to other organs  

Cancer.gov

Scientists at The University of Texas MD Anderson Cancer Center have found that cancer cells traveling to other sites have different energy needs from their “stay-at-home” siblings which continue to proliferate at the original tumor site.

275

MD Anderson researchers discover gene that might predict aggressive prostate cancer at diagnosis  

Cancer.gov

Researchers at The University of Texas MD Anderson Cancer Center have identified a biomarker living next door to the KLK3 gene that could predict which GS7 prostate cancer patients will have a more aggressive form of cancer.

276

75 FR 34170 - Plastic Omnium Automotive Exteriors, LLC, Anderson, SC; Plastic Omnium Automotive Exteriors, LLC...  

Federal Register 2010, 2011, 2012, 2013, 2014

...TA-W-73,230; TA-W-73,230A] Plastic Omnium Automotive Exteriors, LLC, Anderson, SC; Plastic Omnium Automotive Exteriors, LLC, Troy...March 18, 2010, applicable to workers of Plastic Omnium Automotive Exteriors, LLC,...

2010-06-16

277

M.D. Anderson scientists identify a specialized regulatory T cell that stifles antibody production centers:  

Cancer.gov

A regulatory T cell that expresses three specific genes shuts down the mass production of antibodies launched by the immune system to attack invaders, a team led by scientists at The University of Texas MD Anderson Cancer Center reported...

278

MD Anderson researchers find that drug combination acts against aggressive chronic lymphocytic leukemia  

Cancer.gov

A two-prong approach combining ibrutinib and rituximab (Rituxin) to treat aggressive chronic lymphocytic leukemia (CLL) produced responses with minor side effects in a Phase 2 clinical trial at The University of Texas MD Anderson Cancer Center.

279

What Drives the Choice of a Third Party Logistics Provider? Edward Anderson , Tim Coltman*  

E-print Network

1 What Drives the Choice of a Third Party Logistics Provider? Edward Anderson , Tim Coltman of Economics and Business, University of Sydney, Australia Tim Coltman, Associate Professor, University Byron Keating, Associate Professor, University of Canberra, Australia *Corresponding author: Tim Coltman

Coltman, Tim

280

His Own Synthesis: Corn, Edgar Anderson, and Evolutionary Theory in the 1940s  

Microsoft Academic Search

Tracing the contributions of Edgar Anderson (1897--1969) of the Missouri Botanical Garden to the important discussions in\\u000a evolutionary biology in the 1940s, this paper argues that Anderson turned to corn research rather than play a more prominent\\u000a role in what is now known as the Evolutionary Synthesis. His biosystematic studies of Iris and Tradescantia in the 1930s reflected\\u000a such Synthesis

Kim Kleinman

1999-01-01

281

Kondo hole route to incoherence in the periodic Anderson model  

NASA Astrophysics Data System (ADS)

The interplay of disorder and interactions in strongly correlated electronic systems is a subject of perennial interest. In this work, we have investigated the effect of Kondo-hole type disorder on the dynamics and transport properties of heavy fermion systems. We employ the periodic Anderson model within the framework of coherent potential approximation and dynamical mean field theory. The crossover from lattice coherent behaviour to an incoherent single-impurity behaviour is reflected in all aspects: a highly frequency (?)-dependent hybridization becomes almost flat, the coherence peak in resistivity (per impurity) gives way to a Hammann form that saturates at low temperature (T); the Drude peak and the mid-infrared peak in the optical conductivity vanish almost completely. The zero temperature resistivity can be captured in a closed form expression, and we show how the Nordheim's rule gets strongly modified in these systems. The thermopower exhibits a characteristic peak, which changes sign with increasing disorder, and its location is shown to correspond to the low energy scale of the system (?L). In fact, the thermopower appears to be much more sensitive to disorder variations than the resistivity. A comparison to experiments yields quantitative agreement.

Kumar, Pramod; Vidhyadhiraja, N. S.

2013-03-01

282

Waveguide-excited fluorescence microarray  

NASA Astrophysics Data System (ADS)

Signal-to-noise ratio is a crucial issue in microarray fluorescence read-out. Several strategies are proposed for its improvement. First, light collection in conventional microarrays scanners is quite limited. It was recently shown that almost full collection can be achieved in an integrated lens-free biosensor, with labelled species hybridizing practically on the surface of a sensitive silicon detector [L. Martinelli et al. Appl. Phys. Lett. 91, 083901 (2007)]. However, even with such an improvement, the ultimate goal of real-time measurements during hybridization is challenging: the detector is dazzled by the large fluorescence of labelled species in the solution. In the present paper we show that this unwanted signal can effectively be reduced if the excitation light is confined in a waveguide. Moreover, the concentration of excitation light in a waveguide results in a huge signal gain. In our experiment we realized a structure consisting of a high index sol-gel waveguide deposited on a low-index substrate. The fluorescent molecules deposited on the surface of the waveguide were excited by the evanescent part of a wave travelling in the guide. The comparison with free-space excitation schemes confirms a huge gain (by several orders of magnitude) in favour of waveguide-based excitation. An optical guide deposited onto an integrated biosensor thus combines both advantages of ideal light collection and enhanced surface localized excitation without compromising the imaging properties. Modelling predicts a negligible penalty from spatial cross-talk in practical applications. We believe that such a system would bring microarrays to hitherto unattained sensitivities.

Sagarzazu, Gabriel; Bedu, Mélanie; Martinelli, Lucio; Ha, Khoi-Nguyen; Pelletier, Nicolas; Safarov, Viatcheslav I.; Weisbuch, Claude; Gacoin, Thierry; Benisty, Henri

2008-04-01

283

GROUP 1 GROUP 2 GROUP 3 GROUP 4 GROUP 5 GROUP 6 CARR, DANIEL ANDERSON, JENNY BANGU, LINA ABATE BESSOMO, ANNA BEHAN, LIAM ANDERSON, ARAN  

E-print Network

GROUP 1 GROUP 2 GROUP 3 GROUP 4 GROUP 5 GROUP 6 CARR, DANIEL ANDERSON, JENNY BANGU, LINA ABATE, DYLAN CONNAUGHTON, LARA CLIFFORD, NIAMH ENNIS, SEAN DENNEHY, ROSEMARY DINGEMANS, ALEX HUGHES, ALAN, MICHELLE OBRIEN, DANIEL JORDAN, EMILY MC ELROY, ALEXANDER MC MAHON, MARK MILEY, HUGO MULLIGAN, LIAM PAHUJA

O'Mahony, Donal E.

284

Local magnitude scale in Slovenia  

NASA Astrophysics Data System (ADS)

In the paper a calibration study of the local magnitude scale in Slovenia is presented. The Seismology and Geology Office of the Slovenian Environment Agency routinely reports the magnitudes MLV of the earthquakes recorded by the Slovenian seismic stations. The magnitudes are computed from the maximum vertical component of the ground velocity with the magnitude equation that was derived some thirty years ago by regression analysis of the magnitudes recorded by a Wood-Anderson seismograph in Trieste and a short period seismograph in Ljubljana. In the study the present single magnitude MLV equation is replaced by a general form of the Richter local magnitude MWA equation. The attenuation function and station-component corrections that compensate the local effects near seismic stations are determined from the synthetic Wood-Anderson seismograms of a large data set by iterative least-square method. The data set used consists of approximately 18 000 earthquakes during a period of 14 yr, each digitally recorded on up to 29 stations. The derived magnitude equation is used to make the final comparison between the new MWA magnitudes and the routinely calculated MLV magnitudes. The results show good overall accordance between both magnitude equations. The main advantage of the introduction of station-component corrections is the reduced uncertainty of the local magnitude that is assigned to a certain earthquake.

Bajc, J.; Zaplotnik, Ž.; Živ?i?, M.; ?arman, M.

2013-04-01

285

Anderson Localization for the Almost Mathieu II: Point Spectrum for ? 2  

E-print Network

is supposed to be ''irrational enough'' since for rational ! the potential is periodic and the spectrum for this belief was that for â?? ? 2 and irrational ! the Lyapunov exponents are positive; that proves the absence address: International Institute of Earthquake Prediction Theory and Mathematical Geo­ physics. Moscow

286

Strong Coupling to Two-Dimensional Anderson Localized Modes A. Caze, R. Pierrat, and R. Carminati*  

E-print Network

with quantum dots or molecules [8­12]. Multiple scattering in disordered media provides an alter- native route cavities [4] and in condensed matter using quantum-well or quantum-dot excitons in microcavities modifications of the spontaneous decay rate (Purcell effect) have been demonstrated using quantum dots

Paris 7 - Denis Diderot, Université

287

Acoustically excited heated jets. 1: Internal excitation  

NASA Technical Reports Server (NTRS)

The effects of relatively strong upstream acoustic excitation on the mixing of heated jets with the surrounding air are investigated. To determine the extent of the available information on experiments and theories dealing with acoustically excited heated jets, an extensive literature survey was carried out. The experimental program consisted of flow visualization and flowfield velocity and temperature measurements for a broad range of jet operating and flow excitation conditions. A 50.8-mm-diam nozzle was used for this purpose. Parallel to the experimental study, an existing theoretical model of excited jets was refined to include the region downstream of the jet potential core. Excellent agreement was found between theory and experiment in moderately heated jets. However, the theory has not yet been confirmed for highly heated jets. It was found that the sensitivity of heated jets to upstream acoustic excitation varies strongly with the jet operating conditions and that the threshold excitation level increases with increasing jet temperature. Furthermore, the preferential Strouhal number is found not to change significantly with a change of the jet operating conditions. Finally, the effects of the nozzle exit boundary layer thickness appear to be similar for both heated and unheated jets at low Mach numbers.

Lepicovsky, J.; Ahuja, K. K.; Brown, W. H.; Salikuddin, M.; Morris, P. J.

1988-01-01

288

Possible Quantitative Criteria for the Mott and Anderson Transitions in Doped Uncompensated Systems  

NASA Astrophysics Data System (ADS)

Metal-insulator transitions (MITs) in doped uncompensated systems are investigated in the Mott-Hubbard and Anderson impurity models by considering the intercarrier correlation and screening effect of carriers in the same hydrogenic impurity center, the formation of the superlattices with different coordination numbers (z=6, 8 and 12) and by studying the effect of randomness in impurity distribution. We have obtained simple and quite general criteria for the Mott and Anderson transitions and used these criteria to describe quantitatively the correlation and disorder-induced MITs in doped semiconductors and high-Tc cuprates. We examine the validity of the obtained criteria for the Mott and Anderson MITs in these doped systems. It is found that the newly derived criteria for the Mott MIT are well satisfied in doped semiconductors, but they cannot be used to describe the observed MITs in the hole-doped high-Tc cuprates, whereas the newly derived criteria for the Anderson MIT are applicable equally to describe the MITs observed both in doped semiconductors (at weak and intermediate disorders) and in doped cuprates (at intermediate and strong disorders). The new criteria for the Anderson MIT are extended to the polaronic systems in p-type cuprates. Our results are in quantitative agreement with the existing well-established experimental data and shed more light on the different types of MITs that occur in doped uncompensated semiconductors and cuprates.

Dzhumanov, S.; Kurbanov, U. T.; Kurmantayev, A.

289

Spatiotemporal control of nanooptical excitations  

PubMed Central

The most general investigation and exploitation of light-induced processes require simultaneous control over spatial and temporal properties of the electromagnetic field on a femtosecond time and nanometer length scale. Based on the combination of polarization pulse shaping and time-resolved two-photon photoemission electron microscopy, we demonstrate such control over nanoscale spatial and ultrafast temporal degrees of freedom of an electromagnetic excitation in the vicinity of a nanostructure. The time-resolved cross-correlation measurement of the local photoemission yield reveals the switching of the nanolocalized optical near-field distribution with a lateral resolution well below the diffraction limit and a temporal resolution on the femtosecond time scale. In addition, successful adaptive spatiotemporal control demonstrates the flexibility of the method. This flexible simultaneous control of temporal and spatial properties of nanophotonic excitations opens new possibilities to tailor and optimize the light–matter interaction in spectroscopic methods as well as in nanophotonic applications. PMID:20212153

Aeschlimann, Martin; Bauer, Michael; Bayer, Daniela; Brixner, Tobias; Cunovic, Stefan; Dimler, Frank; Fischer, Alexander; Pfeiffer, Walter; Rohmer, Martin; Schneider, Christian; Steeb, Felix; Strüber, Christian; Voronine, Dmitri V.

2010-01-01

290

Receiver-exciter controller design  

NASA Astrophysics Data System (ADS)

A description of the general design of both the block 3 and block 4 receiver-exciter controllers for the Deep Space Network (DSN) Mark IV-A System is presented along with the design approach. The controllers are designed to enable the receiver-exciter subsystem (RCV) to be configured, calibrated, initialized and operated from a central location via high level instructions. The RECs are designed to be operated under the control of the DMC subsystem. The instructions are in the form of standard subsystem blocks (SSBs) received via the local area network (LAN). The centralized control provided by RECs and other DSCC controllers in Mark IV-A is intended to reduce DSN operations costs from the Mark III era.

Jansma, P. A.

1982-06-01

291

Receiver-exciter controller design  

NASA Technical Reports Server (NTRS)

A description of the general design of both the block 3 and block 4 receiver-exciter controllers for the Deep Space Network (DSN) Mark IV-A System is presented along with the design approach. The controllers are designed to enable the receiver-exciter subsystem (RCV) to be configured, calibrated, initialized and operated from a central location via high level instructions. The RECs are designed to be operated under the control of the DMC subsystem. The instructions are in the form of standard subsystem blocks (SSBs) received via the local area network (LAN). The centralized control provided by RECs and other DSCC controllers in Mark IV-A is intended to reduce DSN operations costs from the Mark III era.

Jansma, P. A.

1982-01-01

292

Analysis of the shift in the superconducting transition under pressure in the Anderson-Hubbard two-orbital model  

NASA Astrophysics Data System (ADS)

The two-orbital Hubbard model is used to obtain formulas for the fermion excitation spectrum in the energy bands hybridized by Anderson's interaction. A transition to the Hubbard operators, which diagonalizes the one-site part of the Hamiltonian, allows us to use the Green's temperature function technique to take into account the interstitial jump term while studying the superconducting properties of the model. An analysis of the lower part of the energy spectrum leads to a formula for the superconducting transition temperature Tc associated with the pairing of quasiparticles in one of the correlated bands. The dependence of Tc on electron concentration and energy parameters determining the intraatomic correlation is studied. Proposing a simple relation between the value of pressure (P) and width of the correlated band, the dependence of Tc on the pressure was defined. Good agreement between the theoretical calculation of the dependence of Tc on the pressure and the experimental results for Y1-xPrxBa2Cu3O7-? is found. Comparison of the theoretical and experimental results for the dependence of Tc and its derivative d(ln Tc)/dP on Sr and Bi-content (x) in La2-xSrxCuO4 has been made. It is concluded that the model under consideration can be used for the description of the shift in Tc under pressure for a number of superconductors.

Kosov, A. A.

1998-03-01

293

Explicit finite volume criteria for localization in continuous random media and applications  

Microsoft Academic Search

We give finite volume criteria for localization of quantum or classical waves in continuous random media. We provide explicit conditions, depending on the parameters of the model, for starting the bootstrap multiscale analysis. A simple application to Anderson Hamiltonians on the continuum yields localization at the bottom of the spectrum in an interval of size C? for large ?, where

François Germinet; Abel Klein

2003-01-01

294

Analysis of Anderson-Grüneisen parameter under high temperature in alkaline earthoxides  

NASA Astrophysics Data System (ADS)

The Anderson-Grüneisen parameter ( ?) is of considerable importance to Earth scientists because it sets limitations on the thermo-elastic properties of the lower mantle and core. However, there are several formulations on the Grüneisen parameter, which are in frequent use and predict varying dependence of ? as a function of temperature. In this paper, the expressions for thermal expansion, thermal expansion coefficients and bulk modulus are obtained considering the anharmonic dependence on temperature and are applied to study these constants to alkaline earth oxides. Using the derived expressions, we have shown that different parameters on which the Anderson-Grüneisen parameter ( ?) depends are temperature dependent, but above all the Anderson-Grüneisen parameter ( ?) is independent of temperature. The results obtained have been found to be comparable to experimentaldata.

Pandey, Vipra; Gupta, Seema; Tomar, D. S.; Goyal, S. C.

2010-12-01

295

Abrupt physical and chemical changes during 1992-1999, Anderson Springs, SE Geyser Geothermal Field, California  

USGS Publications Warehouse

The Anderson Springs area is located about 90 miles (145 kilometers) north of San Francisco, California, in the southwestern part of Lake County. The area was first developed in the late 1800s as a health resort, which was active until the 1930s. Patrons drank a variety of cool to hot mineral waters from improved springs, swam in various baths and pools, and hiked in the rugged hills flanking Anderson Creek and its tributaries. In the bluffs to the south of the resort were four small mercury mines of the eastern Mayacmas quicksilver district. About 1,260 flasks of mercury were produced from these mines between 1909 and 1943. By the early 1970s, the higher ridges south and west of Anderson Springs became part of the southeast sector of the greater Geysers geothermal field. Today, several electric power plants are built on these ridges, producing energy from a vapor-dominated 240 °C reservoir. Only the main hot spring at Anderson Springs has maintained a recognizable identity since the 1930s. The hot spring is actually a cluster of seeps and springs that issue from a small fault in a ravine southwest of Anderson Creek. Published and unpublished records show that the maximum temperature (Tm) of this cluster fell gradually from 63°C in 1889 to 48°C in 1992. However, Tm of the cluster climbed to 77°C in 1995 and neared boiling (98°C) in 1998. A new cluster of boiling vents and small fumaroles (Tm = 99.3°C) formed in 1998 about 30 m north of the old spring cluster. Several evergreen trees on steep slopes immediately above these vents apparently were killed by the new activity. Thermal waters at Anderson Hot Springs are mostly composed of near-surface ground waters with some added gases and condensed steam from The Geysers geothermal system. Compared to gas samples from Southeast Geysers wells, the hot spring gases are higher in CO2 and lower in H2S and NH3. As the springs increased in temperature, however, the gas composition became more like the mean composition of steam discharges from the Southeast Geysers. The hot spring waters are low in ions of Cl, B, and Li, but relatively high in HCO3, SO4 and NH4. The stable-isotope compositions (deuterium and oxygen-18) of these waters plot near the global meteoric water line. Geochemical data through time reveal apparent maxima in the concentrations of SO4, Fe, and Mn in 1991 to 1992, before the cluster became hotter. The black-to-gray deposits from the new spring cluster are rich in pyrite and contain anomalous metals. About one-half mile to the east of the hot springs, mineralized water discharges intermittently from an old adit of the Schwartz (Anderson) mine, and enters a tributary of Anderson Creek. This drainage increased substantially in July 1998, and a slurry of mine water and precipitates were transported down the tributary and into Anderson Creek. In December 1998, the adit water was 22°C, and had a chemical composition that was similar to spring waters that once discharged in the ravines surrounding the old Anderson Springs resort. The cause for the abrupt changes that have occurred in thermal features at Anderson Springs is still not resolved. One possibility is that these changes are a response to withdrawal of steam from The Geysers geothermal field over more than 20 years of production. Pressure declines in the geothermal reservoir may have caused a "drying out" of the overlying condensation zone. Induced boiling in this zone and upflow of deep steam to shallower depths would cause heating and vaporization of shallow ground waters. In addition, earthquakes occurring in the vicinity of Anderson Springs have increased significantly after nearby geothermal power plants began operation. These earthquakes may have enhanced surface discharge of thermal fluids along fractures and faults.

Janik, Cathy J.; Goff, Fraser; Walter, Stephen R.; Sorey, Michael L.; Counce, Dale; Colvard, Elizabeth M.

2000-01-01

296

CONSTITUTIONAL LAW--Due Process and Equal Protection--Price-Anderson Act's $560,000,000 Limit on Liability From A nuclear Power Plant Accident Is Unconstitutional  

Microsoft Academic Search

Article summarizes Carolina Environmental Study Group v United States Atomic Energy Commission and congressional intent of the Price-Anderson Act. Article then speculates that the Price-Anderson Act will be found to be unconstitutional by the Supreme Court

Michael Fitzgerald

1978-01-01

297

VOLUME 83, NUMBER 24 P H Y S I C A L R E V I E W L E T T E R S 13 DECEMBER 1999 Excitation of a Three-Dimensionally Localized Atomic Electron Wave Packet  

E-print Network

of a Three-Dimensionally Localized Atomic Electron Wave Packet Jake Bromage and C. R. Stroud, Jr prepared an atomic electron in a three-dimensionally localized wave packet that travels along a highly the earliest days of atomic electron wave packet research has been to produce a three-dimensionally localized

Stroud Jr., Carlos R.

298

Observation of the Anderson metal-insulator transition with atomic matter waves: Theory and experiment  

SciTech Connect

Using a cold atomic gas exposed to laser pulses - a realization of the chaotic quasiperiodic kicked rotor with three incommensurate frequencies - we study experimentally and theoretically the Anderson metal-insulator transition in three dimensions. Sensitive measurements of the atomic wave function and the use of finite-size scaling techniques make it possible to unambiguously demonstrate the existence of a quantum phase transition and to measure its critical exponents. By taking proper account of systematic corrections to one-parameter scaling, we show the universality of the critical exponent {nu}=1.59{+-}0.01, which is found to be equal to the one previously computed for the Anderson model.

Lemarie, Gabriel; Delande, Dominique [Laboratoire Kastler Brossel, UPMC-Paris 6, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France); Chabe, Julien; Szriftgiser, Pascal; Garreau, Jean Claude [Laboratoire PhLAM, , Universite de Lille 1, CNRS, CERLA, F-59655 Villeneuve d'Ascq Cedex (France); Gremaud, Benoit [Laboratoire Kastler Brossel, UPMC-Paris 6, ENS, CNRS, 4 Place Jussieu, F-75005 Paris (France); Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore)

2009-10-15

299

Localization for transversally periodic random potentials on binary trees  

E-print Network

We consider a random Schr\\"odinger operator on the binary tree with a random potential which is the sum of a random radially symmetric potential, $Q_r$, and a random transversally periodic potential, $\\kappa Q_t$, with coupling constant $\\kappa$. Using a new one-dimensional dynamical systems approach combined with Jensen's inequality in hyperbolic space (our key estimate) we obtain a fractional moment estimate proving localization for small and large $\\kappa$. Together with a previous result we therefore obtain a model with two Anderson transitions, from localization to delocalization and back to localization, when increasing $\\kappa$. As a by-product we also have a partially new proof of one-dimensional Anderson localization at any disorder.

Richard Froese; Darrick Lee; Christian Sadel; Wolfgang Spitzer; Günter Stolz

2014-08-18

300

Exact diagonalization analysis of the Anderson-Hubbard model and comparison to real-space self-consistent Hartree-Fock solutions  

NASA Astrophysics Data System (ADS)

We have obtained the exact ground state wave functions of the Anderson-Hubbard model for different electron fillings on a 4x4 lattice with periodic boundary conditions. When compared to the uncorrelated ground states (Hubbard interaction set to zero) we have found evidence of very effective screening, producing smaller charge inhomogeneities due to the Hubbard interaction, particularly at 1/2 filling, and have successfully modelled these local charge densities with non-interacting electrons that experience a static screening of the impurity potentials. Further, we have compared such wave functions to self-consistent real-space unrestricted Hartree-Fock solutions and have found that these approximate ground state wave functions are very successful at reproducing the local charge densities, and may indicate the role of dipolar backflow in producing a novel metallic state in two dimensions.

Chen, Xi; Leung, Pakwo; Gooding, Robert

2008-03-01

301

8. POWERHOUSE INTERIOR SHOWING EXCITER No. 1 IN FOREGROUND, EXCITER ...  

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

8. POWERHOUSE INTERIOR SHOWING EXCITER No. 1 IN FOREGROUND, EXCITER No. 2., AND GENERATOR UNITS BEHIND EXCITER No. 2 IN BACKGROUND. EXCITER No. 1 GENERATOR HAS A COVER OVER TOP HALF OF COMMUTATOR ELEMENT. VIEW TO NORTHWEST. - Rush Creek Hydroelectric System, Powerhouse Exciters, Rush Creek, June Lake, Mono County, CA

302

MD Anderson study finds telomere failure, telomerase activation drive prostate cancer progression  

Cancer.gov

Genomic instability caused by an erosion of the protective caps on chromosomes, followed by activation of an enzyme that reinforces those caps, allows malignant cells to evade destruction and acquire more deadly characteristics, MD Anderson Cancer Center researchers report in an Online Now article at the journal Cell.

303

Mobile Contagion: Simulation of Infection & Defense Everett Anderson Kevin Eustice Shane Markstrum Mark Hansen Peter Reiher  

E-print Network

't go through the firewall, and it is thus free to infect the entire network. Many sites had seriousMobile Contagion: Simulation of Infection & Defense Everett Anderson Kevin Eustice Shane Markstrum can prevent infection of a network from the outside. However, as several recent worms have shown

California at Los Angeles, University of

304

Greg Anderson Bates College click here How to Make Simple Solutions and Dilutions !  

E-print Network

NOTE:.. Greg Anderson Bates College click here How to Make Simple Solutions and Dilutions ! ! Unit # ' 0 ! # ' 9 #12;!# ' 7 ! ! ! .4 #.' ! 8 #.' ! 7 :4 0 0 0 0 # 4 3. Serial Dilution.. serial dilution. Making fixed volumes of specific concentrations from liquid reagents: V1C1=V2C2.. C D + ! + e g , + . V

Ray, David

305

Thomas Young's research on fluid transients: 200 years on Arris S Tijsseling Alexander Anderson  

E-print Network

years ago Thomas Young (1773-1829) published a paper entitled "Hydraulic Investigations, s1 Thomas Young's research on fluid transients: 200 years on Arris S Tijsseling Alexander Anderson The Netherlands United Kingdom ABSTRACT Thomas Young published in 1808 his famous paper (1) in which he derived

Eindhoven, Technische Universiteit

306

Generation of the S boxes of Tiger Ross Anderson 1 and Eli Biham 2  

E-print Network

Generation of the S boxes of Tiger Ross Anderson 1 and Eli Biham 2 1 Cambridge University, England algorithm of the S boxes of Tiger uses the compression func­ tion of Tiger in order to achieve random the S boxes to the unity columns, and the state to the initial value of the state of Tiger. Then it randomizes

Biham, Eli

307

A Limit Study of JavaScript Parallelism Emily Fortuna Owen Anderson Luis Ceze Susan Eggers  

E-print Network

A Limit Study of JavaScript Parallelism Emily Fortuna Owen Anderson Luis Ceze Susan Eggers Computer://sampa.cs.washington.edu Abstract--JavaScript is ubiquitous on the web. At the same time, the language's dynamic behavior makes on the potential parallelism of JavaScript appli- cations, including popular web pages and standard JavaScript

Anderson, Richard

308

The Implications for Anderson College [South Carolina] of an Administrative Decision on Academic Policy.  

ERIC Educational Resources Information Center

This paper reports a series of events that occurred at Anderson College (South Carolina) as a result of conflict between a college academic policy which allowed students to withdraw from a course without penalty up until the 12th week of a 16 week semester, and a regulation of the state approval agency for veterans education which required that…

Roberts, C. Richard

309

MD Anderson study finds inflammatory mediator promotes colorectal cancer by stifling protective genes:  

Cancer.gov

Chronic inflammation combines with DNA methylation, a process that shuts down cancer-fighting genes, to promote development of colorectal cancer, scientists at The University of Texas MD Anderson Cancer Center report today in the advance online publication of the journal Nature Medicine.

310

M.D. Anderson study finds previously unconnected molecular networks conspire to promote cancer:  

Cancer.gov

An inflammation-promoting protein triggers deactivation of a tumor-suppressor that usually blocks cancer formation via the NOTCH signaling pathway, a team of researchers led by scientists at The University of Texas M.D. Anderson Cancer Center reports today in Molecular Cell.

311

Large Scale Numerical Analysis of Scaling Behaviour of the Anderson Transition  

E-print Network

Large Scale Numerical Analysis of Scaling Behaviour of the Anderson Transition TOMI OHTSUKI numerical simulations have made this possible. Different Hamiltonians describing the disor- dered electron] and that the theory may be unsound. The above failures of the field theoretical ap- proach mean that numerical

Katsumoto, Shingo

312

Practical Network Support for IP Traceback Stefan Savage, David Wetherall, Anna Karlin and Tom Anderson  

E-print Network

Anderson Department of Computer Science and Engineering University of Washington Seattle, WA, USA Abstract a general purpose traceback mechanism based on prob- abilistic packet marking in the network. Our approach their sites [16]. Even more worrying, recent reports indicate that at- tackers have developed tools

Paxson, Vern

313

Bibliography Anderson, J.R. (1983). Architecture of cognition. Cambridge, MA: Harvard  

E-print Network

1 Bibliography Anderson, J.R. (1983). Architecture of cognition. Cambridge, MA: Harvard University) "Situated cognition and the role of multi-agent models in explaining language structure." In D. Kudenko, E perspectives. New York: Walter de Gruyter. Brown, J., A. Collins, and P. Duguid. "Situated cognition

Maryland at College Park, University of

314

Gutzwiller variational approximation to the heavy-fermion ground state of the periodic Anderson model  

Microsoft Academic Search

A variational wave function for the Kondo-lattice limit of the periodic Anderson model is evaluated with a Gutzwiller approximation. We obtain a characteristic energy from this coherent wave function of the Kondo form but with a different exponent in the case of finite degeneracy. The effective mass and charge and spin susceptibilities are evaluated, and only in the case of

T. M. Rice; K. Ueda

1985-01-01

315

Polar Sea Ice Mapping Using SeaWinds Data Hyrum S. Anderson and David G. Long  

E-print Network

Polar Sea Ice Mapping Using SeaWinds Data Hyrum S. Anderson and David G. Long Brigham Young for mapping polar sea ice extent. In this study, a new al- gorithm for polar sea ice mapping is developed of Bayes detection to produce sea ice extent maps. Statistical models for sea ice and ocean are represented

Long, David G.

316

Main-Chain Conformational Tendencies of Amino Acids Robert J. Anderson,1,2  

E-print Network

Main-Chain Conformational Tendencies of Amino Acids Robert J. Anderson,1,2 Zhiping Weng,2 Robert K tendencies of an amino acid. Despite forty years of research, the shape of Ramachandran plots is still tendencies among amino acids, and showed that the conformational relationships of amino ac- ids are well

Weng, Zhiping

317

Tor Instead of IP Vincent Liu, Seungyeop Han, Arvind Krishnamurthy, Thomas Anderson  

E-print Network

Tor Instead of IP Vincent Liu, Seungyeop Han, Arvind Krishnamurthy, Thomas Anderson University, and denial of service. Al- though anonymizing overlays such as Tor [2] provide some help to end users approach: instead of running Tor on top of IP, we propose to run Tor instead of IP. We ask: what might

Krishnamurthy, Arvind

318

MD Anderson-led preclinical research shows normal gene hinders breast cancer chemotherapy  

Cancer.gov

Presence of normal p53, a tumor suppressor gene, instead of a mutated version, makes breast cancer chemotherapy with doxorubicin less effective. The preclinical study led by MD Anderson scientists was published today in the journal Cancer Cell. The research, which challenges the existing paradigm, is another step closer to personalized cancer medicine for breast cancer.

319

MD Anderson researchers compare treatments, survival benefits for early-stage lung cancer  

Cancer.gov

Removal of the entire lobe of lung may offer patients with early-stage lung cancer better overall survival when compared with a partial resection, and stereotactic ablative radiotherapy (SABR) may offer the same survival benefit as a lobectomy for some patients, according to a study from The University of Texas MD Anderson Cancer Center.Click here to read the full press release.

320

SUBSIDY TO NUCLEAR POWER THROUGH PRICE-ANDERSON LIABILITY LIMIT: COMMENT  

Microsoft Academic Search

Dubin and Rothwell (1990) use details of insurance premiums to develop a methodology for inferring the value to nuclear operators of the Price-Anderson liability limit from but misinterpret the terms of the insurance contracts for which the premiums are paid. This leads them to overstate the subsidy due to the limit by a factor of between four and ten. Copyright

ANTHONY G. HEYES; CATHERINE LISTON-HEYES

1998-01-01

321

BSA Supp Price-Anderson (Apr. 2010) 1 of 6 BROOKHAVEN SCIENCE ASSOCIATES, LLC  

E-print Network

AND CONDITIONS PRICE-ANDERSON ACT AT BROOKHAVEN NATIONAL LABORATORY 1. DEAR 952.250-70 Nuclear Hazards Indemnity protection to cover public liability, as described in paragraph (d)(2) below. DOE may, however, at any time and in such amount as DOE shall determine to be appropriate to cover such public liability, provided that the costs

Ohta, Shigemi

322

Journal of Philosophy, Inc. Author(s): Alan Ross Anderson and Nuel D. Belnap, Jr.  

E-print Network

Journal of Philosophy, Inc. Enthymemes Author(s): Alan Ross Anderson and Nuel D. Belnap, Jr. Source: The Journal of Philosophy, Vol. 58, No. 23, American Philosophical Association Eastern Division Fifty: Journal of Philosophy, Inc. Stable URL: http://www.jstor.org/stable/2023169 Accessed: 28/05/2009 15

Belnap, Nuel

323

Anderson v. University of Wisconsin: Handicap and Race Discrimination in Readmission Procedures.  

ERIC Educational Resources Information Center

"Anderson v. University of Wisconsin" gives important guidance to universities by detailing the components of race and handicap discrimination claims, and illustrating how these claims can succeed. Readmission procedures that could reduce the likelihood of charges of discrimination are suggested. (Author/MLW)

Smith, Elizabeth R.

1989-01-01

324

Study led by MD Anderson scientists identifies prostate cancer stem cells among low-PSA cells  

Cancer.gov

Prostate cancer cells that defy treatment and display heightened tumor-generating capacity can be identified by levels of prostate specific antigen (PSA) expressed in the tumor cells, a research team led by scientists at The University of Texas MD Anderson Cancer Center reports in the May 3 edition of Cell Stem Cell.

325

CO2 Mitigation Costs for Canada and the Alberta Oil Sands Justin David Anderson  

E-print Network

, alternative to fossil fuels. The results are also dependent, to a lesser extent, on international CO2 policyCO2 Mitigation Costs for Canada and the Alberta Oil Sands By Justin David Anderson Bachelor. Impact and cost assessments aim to alleviate some of these difficulties by attempting to treat the costs

326

Decadal climate cycles and declining Columbia River salmon James J. Anderson  

E-print Network

1 Decadal climate cycles and declining Columbia River salmon James J. Anderson School of Fisheries - This paper explores the effects of the interaction of anthropogenic trends and climate cycles on salmon river salmon production resulted from the interactions of human activities and climatic regime shifts

Washington at Seattle, University of

327

UT MD Anderson study finds metabolic protein plays unexpected role in tumor cell formation and growth:  

Cancer.gov

The embryonic enzyme pyruvate kinase M2 (PKM2) has a well-established role in metabolism and is highly expressed in human cancers. Now, a team led by researchers at The University of Texas MD Anderson Cancer Center reports in advance online publication of the journal Nature that PKM2 has important non-metabolic functions in cancer formation.

328

PLAYING SMART ANOTHER LOOK AT ARTIFICIAL INTELLIGENCE IN COMPUTER GAMES Eike F Anderson  

E-print Network

1 PLAYING SMART ­ ANOTHER LOOK AT ARTIFICIAL INTELLIGENCE IN COMPUTER GAMES Eike F Anderson12 5BB, UK E-mail: eanderson@bournemouth.ac.uk KEYWORDS artificial intelligence, computer games, non intelligence in general and artificial intelligence in the context of its use in modern computer games

Davies, Christopher

329

Engaging with Massive Online Courses Ashton Anderson Daniel Huttenlocher Jon Kleinberg Jure Leskovec  

E-print Network

visible recent developments in education--the deployment of massive open online courses. With their global; online engagement; badges. 1. INTRODUCTION Massive open online courses, or MOOCs, have recently garEngaging with Massive Online Courses Ashton Anderson Daniel Huttenlocher Jon Kleinberg Jure

Thrun, Sebastian

330

Real-Time Character Animation for Computer Games Eike F Anderson  

E-print Network

Real-Time Character Animation for Computer Games Eike F Anderson National Centre for Computer Animation Bournemouth University ABSTRACT The importance of real-time character animation in computer games is continuously growing. This paper will present and discuss various methods of 3D character animation

Davies, Christopher

331

Inference of Tamoxifen's Effects on Prevention of Breast U T M. D. Anderson Cancer Center  

E-print Network

Inference of Tamoxifen's Effects on Prevention of Breast Cancer by Yu Shen U T M. D. Anderson the efficacy of tamoxifen in the prevention of breast cancer among women at high risk of developing the disease. The effect of tamoxifen on the time to diagnosis of the disease over the six-year follow-up of the trial has

Jin, Jiashun

332

The Design of the Mirage Spatial Wiki Nels Anderson, Adam Bender, Carl Hartung,  

E-print Network

The Design of the Mirage Spatial Wiki Nels Anderson, Adam Bender, Carl Hartung, Gaurav Kulkarni of and experience with the Mirage Spatial Wiki. We describe the design decisions that have led to a system with the Mirage Spatial Wiki, a loca- tion based information system that is easy to deploy and use. Location based

Mulligan, Jane

333

Lamport on Mutual Exclusion: 27 Years of Planting Seeds James H. Anderson  

E-print Network

is struck by the many \\seeds" that Lamport ended up plant- ing along the way | seeds that have grownLamport on Mutual Exclusion: 27 Years of Planting Seeds James H. Anderson Department of Computer. This work sparked 15 years of subsequent research within the distributed algorithms community on wait-free

Anderson, James

334

PowerAware Technology Mapping for LUTBased FPGAs Jason H. Anderson and Farid N. Najm  

E-print Network

consumption of FPGAs is beneficial as it leads to lower packaging and cooling costs as well as improvesPower­Aware Technology Mapping for LUT­Based FPGAs Jason H. Anderson and Farid N. Najm Department@eecg.toronto.edu, f.najm@utoronto.ca Abstract We present a new power­aware technology mapping technique for LUT

Najm, Farid N.

335

MD Anderson study finds everolimus prolongs progression-free survival for patients with neuroendocrine tumors:  

Cancer.gov

Combination treatment with everolimus, an inhibitor of the mammalian target rapamycin (mTOR), and octreotide has shown to improve progression-free survival for patients with advanced neuroendocrine tumors and a history of carcinoid syndrome, according to researchers at The University of Texas MD Anderson Cancer Center.

336

MD Anderson develops prognostic model for MDS related to prior cancer therapy  

Cancer.gov

A large-scale analysis of patients whose myelodysplastic syndrome is related to earlier cancer treatment overturns the notion that all of them have a poor prognosis, researchers from the University of Texas MD Anderson Cancer Center report at the 53rd Annual Meeting of the American Society of Hematology.

337

MD Anderson study identifies novel therapeutic targets for small cell lung cancer  

Cancer.gov

Newly discovered molecular differences between small cell lung cancer and non-small cell lung cancer have revealed PARP1 and EZH2 as potential therapeutic targets for patients with small cell lung cancer, according to the results of a University of Texas MD Anderson study published in Cancer Discovery, a journal of the American Association for Cancer Research.

338

Plate Tectonics as a Far-From-Equilibrium Self-Organized System Don L. Anderson  

E-print Network

Plate Tectonics as a Far- From- Equilibrium Self-Organized System By Don L. Anderson Word Count: 3 and other forces at the top. Plate tectonics was once regarded as passive motion of plates on top of mantle convection cells but it now appears that continents and plate tectonics organize the flow in the mantle

Anderson, Don L.

339

MD Anderson scientists discover marker to identify, attack breast cancer stem cells  

Cancer.gov

Breast cancer stem cells wear a cell surface protein that is part nametag and part bull’s eye, identifying them as potent tumor-generating cells and flagging their vulnerability to a drug, researchers at The University of Texas MD Anderson Cancer Center report online in Journal of Clinical Investigation.

340

BRUCE T. ANDERSON Associate Professor, Department of Earth and Environment, Boston University  

E-print Network

's predictability? J. Climate (in review) (6) Anderson, B.T. 2011: Intensification of seasonal extremes given a 2°C-term increase in frequency of seasonal temperature extremes prior to the 2 °C global warming target, Climatic, S.Gopal, and S. Islam, 2010: Observed trends in summertime monsoon precipitation over

Anderson, Bruce

341

BRUCE T. ANDERSON Associate Professor, Department of Earth and Environment, Boston University  

E-print Network

., DOI: 10.1007/s00382-010-0798-y. (9) Anderson, B.T. 2012: Intensification of seasonal extremes given, B.T. 2011: Near-term increase in frequency of seasonal temperature extremes prior to the 2 °C global, S.Gopal, and S. Islam, 2010: Observed trends in summertime monsoon precipitation over

Hutyra, Lucy R.

342

Community of Inquiry in e-Learning: A Critical Analysis of the Garrison and Anderson Model  

ERIC Educational Resources Information Center

This article is based on a constructively critical analysis of the "community of inquiry" model developed by Garrison and Anderson (2003) as part of their "e-learning" research. The authors claim that certain collaborative interactions create "distant presence" fostering the emergence of a "community of inquiry" which has a positive influence on…

Jezegou, Annie

2010-01-01

343

Concurrent Real-Time Music in C++ David P. Anderson yz  

E-print Network

provides pitches, scales, notes, rhythm speci cation, and higher-level musical abstractions. MOOD derives pitches, notes, scales, rhythms, and higher-level musical abstractions. Figure 1 shows the MOOD classConcurrent Real-Time Music in C++ David P. Anderson yz Je Bilmesy

Bilmes, Jeff

344

SILK { a playful blend of Scheme and Java Kenneth R. Anderson, BBN Technologies, Cambridge, MA  

E-print Network

SILK { a playful blend of Scheme and Java Kenneth R. Anderson, BBN Technologies, Cambridge, MA) interpreter in Java [after [6] p. 176]. Abstract SILK (Scheme in about 50 K) is a compact Scheme imple- mented Scheme in Java, but its access to Java was awkward. The current version has altered SILK's syntax

Strickland, Stevie

345

Calculating Polynomial Runtime Properties Hugh Anderson, Siau-Cheng Khoo, Stefan Andrei and Beatrice Luca  

E-print Network

Calculating Polynomial Runtime Properties Hugh Anderson, Siau-Cheng Khoo, Stefan Andrei programming languages. The same style of analysis is also capable of compactly recording and calculating other. In this paper we show how precise poly- nomial bounds on such costs may be calculated on programs, by a char

Khoo, Siau Cheng

346

Review of Philip Anderson, 2008, The Secret Life of Real Estate  

Microsoft Academic Search

Anderson establishes the reality of an 18-year cycle in real estate prices, 1800 to date, emphasizing the land element, mainly urban land and subsoil resources. He relates this to privatization, which he calls “enclosureâ€, although he does not trace the history back to the 16th Century enclosure movement in England, nor recommend undoing privatization. He supports his thesis with a

Mason Gaffney

2009-01-01

347

MD Anderson study finds ovarian cancer patients survive longer with BRCA2 mutated in tumors:  

Cancer.gov

Women with high-grade ovarian cancer live longer and respond better to platinum-based chemotherapy when their tumors have BRCA2 genetic mutations, researchers at The University of Texas MD Anderson Cancer Center and the Institute for Systems Biology report in the Oct. 12 issue of the Journal of the American Medical Association.

348

Dystopian Visions of Global Capitalism: Philip Reeve's "Mortal Engines" and M.T Anderson's "Feed"  

ERIC Educational Resources Information Center

This article examines Philip Reeve's novel for children, "Mortal Engines", and M.T. Anderson's young adult novel, "Feed", by assessing these dystopias as prototypical texts of what Ulrich Beck calls risk society. Through their visions of a fictional future, the two narratives explore the hazards created by contemporary techno-economic progress,…

Bullen, Elizabeth; Parsons, Elizabeth

2007-01-01

349

Quantum transport through disordered 1D wires: Conductance via localized and delocalized electrons  

SciTech Connect

Coherent electronic transport through disordered systems, like quantum wires, is a topic of fundamental and practical interest. In particular, the exponential localization of electron wave functions-Anderson localization-due to the presence of disorder has been widely studied. In fact, Anderson localization, is not an phenomenon exclusive to electrons but it has been observed in microwave and acoustic experiments, photonic materials, cold atoms, etc. Nowadays, many properties of electronic transport of quantum wires have been successfully described within a scaling approach to Anderson localization. On the other hand, anomalous localization or delocalization is, in relation to the Anderson problem, a less studied phenomenon. Although one can find signatures of anomalous localization in very different systems in nature. In the problem of electronic transport, a source of delocalization may come from symmetries present in the system and particular disorder configurations, like the so-called Lévy-type disorder. We have developed a theoretical model to describe the statistical properties of transport when electron wave functions are delocalized. In particular, we show that only two physical parameters determine the complete conductance distribution.

Gopar, Víctor A. [Departamento de Física Teórica and BIFI, Universidad de Zaragoza, Pedro Cerbuna 12, E-50009, Zaragoza (Spain)

2014-01-14

350

Wildlife Protection, Mitigation, and Enhancement Plans, Anderson Ranch and Black Canyon Facilities: Final Report.  

SciTech Connect

Under direction of the Pacific Northwest Electric Power Planning and Conservation Act of 1980, and the subsequent Northwest Power Planning Council's Columbia River Basin Fish and Wildlife Program, projects have been developed in Idaho to mitigate the impacts to wildlife habitat and production due to the development and operation of the Anderson Ranch and Black Canyon Facilities (i.e., dam, power plant, and reservoir areas). The Anderson Ranch Facility covered about 4812 acres of wildlife habitat while the Black Canyon Facility covered about 1115 acres. These acreages include dam and power plant staging areas. A separate mitigation plan has been developed for each facility. A modified Habitat Evaluation Procedure (HEP) was used to assess the benefits of the mitigation plans to wildlife. The interagency work group used the target species Habitat Units (HU's) lost at each facility as a guideline during the mitigation planning process, while considering the needs of wildlife in the areas. Totals of 9619 and 2238 target species HU's were estimated to be lost in the Anderson Ranch and Black Canyon Facility areas, respectively. Through a series of projects, the mitigation plans will provide benefits of 9620 target species HU's to replace Anderson Ranch wildlife impacts and benefits of 2195 target species HU's to replace Black Canyon wildlife impacts. Target species to be benefited by the Anderson Ranch and/or Black Canyon mitigation plans include the mallard, Canada goose, mink, yellow warbler, black-capped chickadee, ruffed grouse, mule deer, blue grouse, sharp-tailed grouse, ring-necked pheasant, and peregrine falcon.

Meuleman, G. Allyn

1987-06-01

351

Excitation of spin waves by an electric current  

Microsoft Academic Search

The excitation of spin waves in an unbounded ferromagnetic film by a direct spin-polarized current distributed over a small area is treated macroscopically. The derived critical threshold current for excitation has two additive terms: The first arises from radiation of spin waves and is constant. The second arises from local viscous dissipation and varies in proportion to damping coefficient, external

J. C Slonczewski

1999-01-01

352

Optimizing Disinfection Pretreatment using Excitation-emission Matrix Fluorescence Spectroscopy  

Microsoft Academic Search

Excitation-emission matrix fluorescence spectroscopy (EEM) can be used to characterize organic matter present in water samples. When excited, the intensity of fluorescence emitted can be used to generate a representation of organic matter makes it possible to localize fluorescence centers related to particular groups, which can ‘fingerprint’ a sample. The technique is applicable to wastewater samples to identify contributors of

Katherine Y. Bell; Juan Sánez; Martha J. M. Wells

2012-01-01

353

Evidence of non-mean-field-like low-temperature behavior in the Edwards-Anderson spin-glass model.  

PubMed

The three-dimensional Edwards-Anderson and mean-field Sherrington-Kirkpatrick Ising spin glasses are studied via large-scale Monte Carlo simulations at low temperatures, deep within the spin-glass phase. Performing a careful statistical analysis of several thousand independent disorder realizations and using an observable that detects peaks in the overlap distribution, we show that the Sherrington-Kirkpatrick and Edwards-Anderson models have a distinctly different low-temperature behavior. The structure of the spin-glass overlap distribution for the Edwards-Anderson model suggests that its low-temperature phase has only a single pair of pure states. PMID:23215219

Yucesoy, B; Katzgraber, Helmut G; Machta, J

2012-10-26

354

Quantum criticality in the pseudogap Bose-Fermi Anderson and Kondo models: Interplay between fermion- and boson-induced Kondo destruction  

NASA Astrophysics Data System (ADS)

We address the phenomenon of critical Kondo destruction in pseudogap Bose-Fermi Anderson and Kondo quantum impurity models. These models describe a localized level coupled both to a fermionic bath having a density of states that vanishes like |?|r at the Fermi energy (?=0) and, via one component of the impurity spin, to a bosonic bath having a sub-Ohmic spectral density proportional to |?|s. Each bath is capable by itself of suppressing the Kondo effect at a continuous quantum phase transition. We study the interplay between these two mechanisms for Kondo destruction using continuous-time quantum Monte Carlo for the pseudogap Bose-Fermi Anderson model with 0localized (Kondo-destroyed) phase. The two solution methods, which are in good agreement in their domain of overlap, provide access to the many-body spectrum, as well as to correlation functions including, in particular, the single-particle Green's function and the static and dynamical local spin susceptibilities. The quantum-critical regime exhibits the hyperscaling of critical exponents and ?/T scaling in the dynamics that characterize an interacting critical point. The (r,s) plane can be divided into three regions: one each in which the calculated critical properties are dominated by the bosonic bath alone or by the fermionic bath alone, and between these two regions, a third in which the bosonic bath governs the critical spin response but both baths influence the renormalization-group flow near the quantum-critical point.

Pixley, J. H.; Kirchner, Stefan; Ingersent, Kevin; Si, Qimiao

2013-12-01

355

Critiquing variational theories of the Anderson Hubbard model: real-space self-consistent Hartree Fock solutions  

NASA Astrophysics Data System (ADS)

A simple and commonly employed approximate technique with which one can examine spatially disordered systems when strong electronic correlations are present is based on the use of real-space unrestricted self-consistent Hartree-Fock wavefunctions. In such an approach the disorder is treated exactly while the correlations are treated approximately. In this paper we critique the success of this approximation by making comparisons between such solutions and the exact wavefunctions for the Anderson-Hubbard model. Due to the sizes of the complete Hilbert spaces for these problems, the comparisons are restricted to small one-dimensional chains, up to ten sites, and a 4 × 4 two-dimensional cluster, and at 1/2-filling these Hilbert spaces contain about 63 500 and 166 million states, respectively. We have completed these calculations both at and away from 1/2-filling. This approximation is based on a variational approach which minimizes the Hartree-Fock energy, and we have completed comparisons of the exact and Hartree-Fock energies. However, in order to assess the success of this approximation in reproducing ground-state correlations we have completed comparisons of the local charge and spin correlations, including the calculation of the overlap of the Hartree-Fock wavefunctions with those of the exact solutions. We find that this approximation reproduces the local charge densities to quite a high accuracy, but that the local spin correlations, as represented by \\langle {\\mathbf {S}}_i\\bdot {\\mathbf {S}}_j\\rangle , are not as well represented. In addition to these comparisons, we discuss the properties of the spin degrees of freedom in the HF approximation, and where in the disorder-interaction phase diagram such physics may be important.

Chen, X.; Farhoodfar, A.; McIntosh, T.; Gooding, R. J.; Leung, P. W.

2008-08-01

356

Laser pulses for coherent xuv Raman excitation  

E-print Network

We combine multi-channel electronic structure theory with quantum optimal control to derive Raman pulse sequences that coherently populate a valence excited state. For a neon atom, Raman target populations of up to 13% are obtained. Superpositions of the ground and valence Raman states with a controllable relative phase are found to be reachable with up to 4.5% population and phase control facilitated by the pump pulse carrier envelope phase. Our results open a route to creating core-hole excitations in molecules and aggregates that locally address specific atoms and represent the first step towards realization of multidimensional spectroscopy in the xuv and x-ray regimes.

Greenman, Loren; Whaley, K Birgitta

2014-01-01

357

10 CFR 8.2 - Interpretation of Price-Anderson Act, section 170 of the Atomic Energy Act of 1954.  

Code of Federal Regulations, 2011 CFR

...Price-Anderson Act, section 170 of the Atomic Energy Act of 1954. 8.2 Section 8.2 Energy NUCLEAR REGULATORY COMMISSION INTERPRETATIONS...Insurance, in Law and Administration in Nuclear Energy 75 (1959). In the testimony...

2011-01-01

358

10 CFR 8.2 - Interpretation of Price-Anderson Act, section 170 of the Atomic Energy Act of 1954.  

Code of Federal Regulations, 2010 CFR

...Price-Anderson Act, section 170 of the Atomic Energy Act of 1954. 8.2 Section 8.2 Energy NUCLEAR REGULATORY COMMISSION INTERPRETATIONS...Insurance, in Law and Administration in Nuclear Energy 75 (1959). In the testimony...

2010-01-01

359

10 CFR 8.2 - Interpretation of Price-Anderson Act, section 170 of the Atomic Energy Act of 1954.  

Code of Federal Regulations, 2012 CFR

...Price-Anderson Act, section 170 of the Atomic Energy Act of 1954. 8.2 Section 8.2 Energy NUCLEAR REGULATORY COMMISSION INTERPRETATIONS...Insurance, in Law and Administration in Nuclear Energy 75 (1959). In the testimony...

2012-01-01

360

Chemistry Professor Larry Anderson teaches his students to look at the big picture when it comes to research about  

E-print Network

1982. "Science has almost no impact on public policy. Public policy is politically driven." Yet are global in scope," Anderson says. "My hope is our students will gain valuable international perspective

361

MD Anderson researchers find that breast cancer spread may be tied to cells that regulate blood flow  

Cancer.gov

Scientists at the University of Texas MD Anderson Cancer Center believe that targeting blood vessel cells known as pericytes may offer a potential new therapeutic approach when combined with vascular growth factors responsible for cell death.

362

2014 Rice University / UT MD Anderson Med Into Grad Program in Translational Cancer Diagnostics & Therapeutics Research for Bioengineers & Biophysicists  

E-print Network

2014 Rice University / UT MD Anderson Med Into Grad Program in Translational Cancer Diagnostics & Therapeutics Research for Bioengineers & Biophysicists Program Details: Rice University and The University Research for Bioengineers and Biophysicists. Doctoral students from Rice's Bioengineering, Biochemistry

Zhang, David Yu

363

Esr of a Magnetic Probe in the Neighborhood of AN Anderson Impurity  

NASA Astrophysics Data System (ADS)

The renormalization group formalism was applied to calculate the spin lattice relaxation rate T1-1 of a magnetic probe located in the neighborhood of a spin degenerate Anderson impurity. In the Kondo regime, T1-1 as a function of the temperature T presents a peak at the Kondo temperature TK. For T?TK, the system behaves as a heavy Fermi liquid, with an enhanced density of states, which increases with the decrease in the Kondo temperature; T1-1T is a universal function of T/?K up to temperatures of the order of 100 ?K, where ?K is the Kondo width for temperatures lower than TK. The spin relaxation rate T1-1 is proportional to the product of the magnetic susceptibility and temperature ?T. Moreover, in the peak, T1-1 at the Kondo temperature decreases with the increase in the distance between the Anderson impurity and the magnetic probe.

Pinto, J. W. M.; Frota, H. O.

364

Electronic excitations of fluoroethylenes  

NASA Astrophysics Data System (ADS)

Several lowest-lying singlet electronic states of vinyl fluoride, trans-, cis-, and 1,1-difluoroethylene, trifluoroethylene, and tetrafluoroethylene were investigated by using symmetry-adapted cluster configuration interaction theory. Basis sets up to Dunning's aug-cc-pVTZ augmented with appropriate Rydberg functions were utilized for the calculations. Calculated excitation energies show a good agreement with the available experimental values. Even in the troublesome ? ??* transitions, the excitation energies obtained in the present study agree well with the experimental values except in one or two fluoroethylenes. Strong mixing between different states was noticed in a few fluoroethylenes; especially the mixing is very strong between ?-? * and ?-3p? states in trifluoroethylene. No pure ?-? * excited state was found in almost all the fluoroethylenes. Several assignments and reassignments of features in the experimental spectra were suggested. The present study does not support the existing argument that the interaction between the ?-? * and ?-? * states is the reason behind the blueshift of around 1.25eV in the ?-?* excitation energy of tetrafluoroethylene. Possible reasons, including structural changes, for this shift are discussed in detail. Several low-lying triplet excited states were also studied.

Arulmozhiraja, Sundaram; Ehara, Masahiro; Nakatsuji, Hiroshi

2007-01-01

365

Electronic excitations of fluoroethylenes.  

PubMed

Several lowest-lying singlet electronic states of vinyl fluoride, trans-, cis-, and 1,1-difluoroethylene, trifluoroethylene, and tetrafluoroethylene were investigated by using symmetry-adapted cluster configuration interaction theory. Basis sets up to Dunning's aug-cc-pVTZ augmented with appropriate Rydberg functions were utilized for the calculations. Calculated excitation energies show a good agreement with the available experimental values. Even in the troublesome pi-->pi(*) transitions, the excitation energies obtained in the present study agree well with the experimental values except in one or two fluoroethylenes. Strong mixing between different states was noticed in a few fluoroethylenes; especially the mixing is very strong between pi-pi(*) and pi-3ppi states in trifluoroethylene. No pure pi-sigma(*) excited state was found in almost all the fluoroethylenes. Several assignments and reassignments of features in the experimental spectra were suggested. The present study does not support the existing argument that the interaction between the pi-pi(*) and sigma-sigma(*) states is the reason behind the blueshift of around 1.25 eV in the pi-pi(*) excitation energy of tetrafluoroethylene. Possible reasons, including structural changes, for this shift are discussed in detail. Several low-lying triplet excited states were also studied. PMID:17286469

Arulmozhiraja, Sundaram; Ehara, Masahiro; Nakatsuji, Hiroshi

2007-01-28

366

Shear layer excitation, experiment versus theory  

NASA Technical Reports Server (NTRS)

The acoustical excitation of shear layers is investigated. Acoustical excitation causes the so-called orderly structures in shear layers and jets. Also, the deviations in the spreading rate between different shear layer experiments are due to the same excitation mechanism. Measurements in the linear interaction region close to the edge from which the shear layer is shed are examined. Two sets of experiments (Houston 1981 and Berlin 1983/84) are discussed. The measurements were carried out with shear layers in air using hot wire anemometers and microphones. The agreement between these measurements and the theory is good. Even details of the fluctuating flow field correspond to theoretical predictions, such as the local occurrence of negative phase speeds.

Bechert, D. W.; Stahl, B.

1984-01-01

367

Odysseus almost makes it to broadway: The Ulysses Africanus of Kurt Weill and Maxwell Anderson  

Microsoft Academic Search

Between the end of 1938 and the beginning of 1939, Kurt Weill and Maxwell Anderson began working together on a musical comedy\\u000a entitledUlysses Africanus, which was intended to be performed on Broadway. The play tells anOdyssey-like story set in the aftermath of the American Civil War. Various problems attended attempts to stage the play, and the\\u000a project was eventually abandoned.

Robert J. Rabel

2007-01-01

368

Magnetic frustration in the three-band Anderson lattice model for high-temperature superconductors  

SciTech Connect

The three-band Anderson lattice model for the CuO{sub 2} planes in high-{Tc} superconductors is established. Treating this model by perturbation theory, the effective spin interactions are derived. The antiferromagnetic superexchange integrals are calculated as functions of the direct oxygen transfer and the hole concentration. It is found that frustration in the superexchange occurs, even in the undoped case, which increases with oxygen trnasfer and decreases with hole concentration.

Ihle, D.; Kasner, M. (Sektion Physik, Karl-Marx-Universitaet Leipzig, DDR-7010 Leipzig (German Democratic Republic))

1990-09-01

369

Bound states in the continuum in a single-level Fano-Anderson model  

E-print Network

Bound states in the continuum (BIC) are shown to exist in a single-level Fano-Anderson model with a colored interaction between the discrete state and a tight-binding continuum, which may describe mesoscopic electron or photon transport in a semi-infinite one-dimensional lattice. The existence of BIC is explained in the lattice realization as a boundary effect induced by lattice truncation.

Stefano Longhi

2006-12-18

370

MD Anderson study finds qigong improves quality of life for breast cancer patients undergoing radiation therapy  

Cancer.gov

Researchers from The University of Texas MD Anderson Cancer Center have found qigong, an ancient mind-body practice, reduces depressive symptoms and improves quality of life in women undergoing radiotherapy for breast cancer. The study, published in the journal Cancer, is the first to examine qigong in patients actively receiving radiation therapy and includes a follow-up period to assess benefits over time.

371

Step-by-step covalent modification of Cr-templated Anderson-type polyoxometalates.  

PubMed

A series of tripodal alcohols substituted Anderson-type polyoxometalates (POMs) including mono-substituted (compounds and ), asymmetrical bi-substituted (compound ), and symmetrical bi-substituted ones (compounds and ) have been synthesized under hydrothermal conditions using a pre-designed step-by-step strategy, and compounds , and have been fully characterized by single-crystal X-ray diffraction, ESI-MS, and elemental analysis. PMID:24695647

Lin, Chang-Gen; Chen, Wei; Long, De-Liang; Cronin, Leroy; Song, Yu-Fei

2014-06-21

372

Critical Metal Phase at the Anderson Metal-Insulator Transition with Kondo Impurities  

Microsoft Academic Search

It is well known that magnetic impurities can change the symmetry class of disordered metallic systems by breaking spin and time-reversal symmetry. At low temperature, these symmetries can be restored by Kondo screening. It is also known that at the Anderson metal-insulator transition, wave functions develop multifractal fluctuations with power-law correlations. Here, we consider the interplay of these two effects.

S. Kettemann; E. R. Mucciolo; I. Varga

2009-01-01

373

Critical metal phase at the Anderson metal-insulator transition with Kondo impurities  

Microsoft Academic Search

It is well known that magnetic impurities can change the symmetry class of disordered metallic systems by breaking spin and time-reversal symmetry. At low temperature, these symmetries can be restored by Kondo screening. It is also known that at the Anderson metal-insulator transition, wave functions develop multifractal fluctuations with power-law correlations. Here, we consider the interplay of these two effects.

Eduardo Mucciolo; Stefan Kettemann; Imre Varga

2010-01-01

374

Two length scales near the Anderson transition and the critical diffusive behavior  

NASA Astrophysics Data System (ADS)

We present results of an analytical and numerical investigation of the Anderson metal-insulator transition based on a supersymmetric non-linear ?-model in effective medium approximation. In the critical metallic regime two characteristic length scales exist which diverge according to a power law but have different critical exponents. We put forward a physical picture that enables us to express the diffusion coefficient in terms of these two lengths and to explain its exponential behavior obtained previously.

Viehweger, O.; Efetov, K. B.

375

MD Anderson study finds Black patients with kidney cancer have poorer survival than whites  

Cancer.gov

Among patients with the most common form of kidney cancer, whites consistently have a survival advantage over blacks, regardless of patient and tumor characteristics or surgical treatment. That is the conclusion of a new University of Texas MD Anderson Cancer Center study published early online in CANCER, a peer-reviewed journal of the American Cancer Society. The study's results suggest that additional efforts are needed to prolong the survival of all patients with kidney cancer.

376

Exciting flavored bound states  

NASA Astrophysics Data System (ADS)

We study ground and radial excitations of flavor singlet and flavored pseudoscalar mesons within the framework of the rainbow-ladder truncation using an infrared massive and finite interaction in agreement with recent results for the gluon-dressing function from lattice QCD and Dyson-Schwinger equations. Whereas the ground-state masses and decay constants of the light mesons as well as charmonia are well described, we confirm previous observations that this truncation is inadequate to provide realistic predictions for the spectrum of excited and exotic states. Moreover, we find a complex conjugate pair of eigenvalues for the excited D(s) mesons, which indicates a non-Hermiticity of the interaction kernel in the case of heavy-light systems and the present truncation. Nevertheless, limiting ourselves to the leading contributions of the Bethe-Salpeter amplitudes, we find a reasonable description of the charmed ground states and their respective decay constants.

Rojas, E.; El-Bennich, B.; de Melo, J. P. B. C.

2014-10-01

377

Fast neutron therapy for locally advanced head and neck tumors  

Microsoft Academic Search

Between October 1972 and April 1979, 187 patients with locally advanced head and neck tumors were treated with 50 MeV\\/sub d ..-->.. Be\\/ neutrons or with conventional treatment in the M.D. Anderson Hospital-Texas A and M University variable energy cyclotron (MDAH-TAMVEC) program. Of these, 114 patients were treated in pilot studies and 73 in a randomized clinical trial. In the

Moshe H. Maor; David H. Hussey; Gilbert H. Fletcher; Richard H. Jesse

1981-01-01

378

Detecting Breather Excitations with Inelastic Tunneling Spectroscopy  

E-print Network

We propose inelastic electron tunneling spectroscopy scanning tunneling microscopy (IETS-STM) as a means of exciting and observing intrinsic localized modes (breathers) in a macromolecule. As a demonstration, inelastic tunneling features of the density of states are calculated for a simple nonlinear elastic Morse chain. The general formalism we have developed for the IETS is applicable to other nonlinear extended objects, such as DNA on a substrate.

Jian-Xin Zhu; K. O. Rasmussen; A. R. Bishop; A. V. Balatsky

2004-07-08

379

Singlet-triplet Hamiltonian for spin excitations in a Kondo insulator  

SciTech Connect

In the nonsymmetric version of the periodic Anderson model for a Kondo insulator, an effective singlet-triplet Hamiltonian H{sub s-t} with indirect antiferromagnetic f-f exchange is constructed, which makes it possible to analyze the dynamic magnetic susceptibility {chi}{sub f}(k, {omega}) of f electrons. Hamiltonian H{sub s-t} is used to describe the experimentally observed dispersion of the three-level spin excitation spectrum in YbB{sub 12}. A distinguishing feature of this analysis is the introduction of small-radius singlet and triplet collective f-d excitations that form low- and high-lying spin bands during motion over the lattice.

Barabanov, A. F., E-mail: abarabanov@mtu-net.r [Russian Academy of Sciences, Institute of High-Pressure Physics (Russian Federation); Maksimov, L. A. [Moscow Institute of Physics and Technology (Russian Federation)

2010-08-15

380

Charge transfer excitations from excited state Hartree-Fock subsequent minimization scheme.  

PubMed

Photoinduced charge-transfer processes play a key role for novel photovoltaic phenomena and devices. Thus, the development of ab initio methods that allow for an accurate and computationally inexpensive treatment of charge-transfer excitations is a topic that nowadays attracts a lot of scientific attention. In this paper we extend an approach recently introduced for the description of single and double excitations [M. Tassi, I. Theophilou, and S. Thanos, Int. J. Quantum Chem. 113, 690 (2013); M. Tassi, I. Theophilou, and S. Thanos, J. Chem. Phys. 138, 124107 (2013)] to allow for the description of intermolecular charge-transfer excitations. We describe an excitation where an electron is transferred from a donor system to an acceptor one, keeping the excited state orthogonal to the ground state and avoiding variational collapse. These conditions are achieved by decomposing the space spanned by the Hartree-Fock (HF) ground state orbitals into four subspaces: The subspace spanned by the occupied orbitals that are localized in the region of the donor molecule, the corresponding for the acceptor ones and two more subspaces containing the virtual orbitals that are localized in the neighborhood of the donor and the acceptor, respectively. Next, we create a Slater determinant with a hole in the subspace of occupied orbitals of the donor and a particle in the virtual subspace of the acceptor. Subsequently we optimize both the hole and the particle by minimizing the HF energy functional in the corresponding subspaces. Finally, we test our approach by calculating the lowest charge-transfer excitation energies for a set of tetracyanoethylene-hydrocarbon complexes that have been used earlier as a test set for such kind of excitations. PMID:24784248

Theophilou, Iris; Tassi, M; Thanos, S

2014-04-28

381

Charge transfer excitations from excited state Hartree-Fock subsequent minimization scheme  

SciTech Connect

Photoinduced charge-transfer processes play a key role for novel photovoltaic phenomena and devices. Thus, the development of ab initio methods that allow for an accurate and computationally inexpensive treatment of charge-transfer excitations is a topic that nowadays attracts a lot of scientific attention. In this paper we extend an approach recently introduced for the description of single and double excitations [M. Tassi, I. Theophilou, and S. Thanos, Int. J. Quantum Chem. 113, 690 (2013); M. Tassi, I. Theophilou, and S. Thanos, J. Chem. Phys. 138, 124107 (2013)] to allow for the description of intermolecular charge-transfer excitations. We describe an excitation where an electron is transferred from a donor system to an acceptor one, keeping the excited state orthogonal to the ground state and avoiding variational collapse. These conditions are achieved by decomposing the space spanned by the Hartree-Fock (HF) ground state orbitals into four subspaces: The subspace spanned by the occupied orbitals that are localized in the region of the donor molecule, the corresponding for the acceptor ones and two more subspaces containing the virtual orbitals that are localized in the neighborhood of the donor and the acceptor, respectively. Next, we create a Slater determinant with a hole in the subspace of occupied orbitals of the donor and a particle in the virtual subspace of the acceptor. Subsequently we optimize both the hole and the particle by minimizing the HF energy functional in the corresponding subspaces. Finally, we test our approach by calculating the lowest charge-transfer excitation energies for a set of tetracyanoethylene-hydrocarbon complexes that have been used earlier as a test set for such kind of excitations.

Theophilou, Iris, E-mail: i.theophilou@fz-juelich.de [Peter Grunberg Institut (PGI) Forschungszentrum Jülich, D-52425 Jülich (Germany)] [Peter Grunberg Institut (PGI) Forschungszentrum Jülich, D-52425 Jülich (Germany); Tassi, M.; Thanos, S. [Institute for Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems, ‘Demokritos’ National Center for Scientific Research, 15310 Athens (Greece)] [Institute for Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems, ‘Demokritos’ National Center for Scientific Research, 15310 Athens (Greece)

2014-04-28

382

Localization on the landscape and eternal inflation  

NASA Astrophysics Data System (ADS)

We investigate the validity of the assertion that eternal inflation populates the landscape of string theory. We verify that bubble solutions do not satisfy the Klein–Gordon equation for the landscape potential. Solutions to the landscape potential within the formalism of quantum cosmology are Anderson localized wavefunctions. These are inconsistent with inflating bubble solutions. The physical reasons behind the failure of a relation between eternal inflation and the landscape are rooted in quantum phenomena such as interference between wavefunction concentrated around the various vacua in the landscape.

Mersini-Houghton, Laura; Perry, Malcolm J.

2014-11-01

383

Localization of nodal quasiparticles and plateau transitions  

NASA Astrophysics Data System (ADS)

In the context of semiconductor physics, we propose a realization of ‘unconventional’ universality class in the problem of Anderson localization. In the beginning, we review our theoretical prediction on the critical phenomena driven by defects. It leads to ‘critical metal’ with continuously varying exponents in two dimensions. And we make some proposals for a realization of the critical metal in e.g. artificially designed semiconductor. Finally, we make some comments on the relation of this problem to the ‘plateau transition’ in e.g. GaAs/AlGaAs heterostructure.

Morita, Y.

2006-04-01

384

Magnetostrictive resonance excitation  

DOEpatents

The resonance frequency spectrum of a magnetostrictive sample is remotely determined by exciting the magnetostrictive property with an oscillating magnetic field. The permeability of a magnetostrictive material and concomitant coupling with a detection coil varies with the strain in the material whereby resonance responses of the sample can be readily detected. A suitable sample may be a magnetostrictive material or some other material having at least one side coated with a magnetostrictive material. When the sample is a suitable shape, i.e., a cube, rectangular parallelepiped, solid sphere or spherical shell, the elastic moduli or the material can be analytically determined from the measured resonance frequency spectrum. No mechanical transducers are required and the sample excitation is obtained without contact with the sample, leading to highly reproducible results and a measurement capability over a wide temperature range, e.g. from liquid nitrogen temperature to the Curie temperature of the magnetostrictive material.

Schwarz, Ricardo B. (Los Alamos, NM); Kuokkala, Veli-Tapani (Tampere, FI)

1992-01-01

385

Elementary excitation and energy landscape in simple liquids  

NASA Astrophysics Data System (ADS)

The nature of excitations in liquids has been a subject of debate for a long time. In liquids, phonons are extremely short-lived and marginalized. Instead, recent research results indicate that local topological or configurational excitations (anankeons) are the elementary excitations in high temperature metallic liquids. Local topological excitations are those which locally alter the atomic connectivity network by cutting or forming atomic bonds, and are directly tied to the atomistic origin of viscosity in the liquid. The local potential energy landscape (PEL) of anankeons represents the probability weighted projection of the global PEL to a single atom. The original PEL is an insightful concept, but is highly multi-dimensional and difficult to characterize or even to visualize. A description in terms of the local PEL for anankeons appears to offer a simpler and more effective approach toward this complex problem. At the base of these advances, is the recognition that atomic discreteness and the topology of atomic connectivity are the most crucial features of the structure in liquids, which current nonlinear continuum theories cannot fully capture. These discoveries could open the way to the explanation of various complex phenomena in liquids, such as atomic transport, fragility, and the glass transition, in terms of these excitations.

Egami, T.

2014-06-01

386

Physical, chemical, and isotopic data for samples from the Anderson Springs area, Lake County, California, 1998-1999  

USGS Publications Warehouse

Anderson Springs is located about 90 miles (145 kilometers) north of San Francisco, California, in the southwestern part of Lake County. The area was first developed in the late 1800s as a health resort, which was active until the 1930s. In the rugged hills to the south of the resort were four small mercury mines of the eastern Mayacmas quicksilver district. About 1,260 flasks of mercury were produced from these mines between 1909 and 1943. In the 1970s, the high-elevation areas surrounding Anderson Springs became part of The Geysers geothermal field. Today, several electric powerplants are located on the ridges above Anderson Springs, utilizing steam produced from a 240°C vapor-dominated reservoir. The primary purpose of this report is to provide physical, chemical, and isotopic data on samples collected in the Anderson Springs area during 1998 and 1999, in response to a Freedom of Information Act request. In July 1998, drainage from the Schwartz adit of the abandoned Anderson mercury mine increased substantially over a 2-day period, transporting a slurry of water and precipitates down a tributary and into Anderson Creek. In August 1998, J.J. Rytuba and coworkers sampled the Schwartz adit drainage and water from the Anderson Springs Hot Spring for base metal and methylmercury analysis. They measured a maximum temperature (Tm) of 85°C in the Hot Spring. Published records show that the temperature of the Anderson Springs Hot Spring (main spring) was 63°C in 1889, 42–52°C from 1974 through 1991, and 77°C in March 1995. To investigate possible changes in thermal spring activity and to collect additional samples for geochemical analysis, C.J. Janik and coworkers returned to the area in September and December 1998. They determined that a cluster of springs adjacent to the main spring had Tm=98°C, and they observed that a new area of boiling vents and small fumaroles (Tm=99.3°C) had formed in an adjacent gully about 20 meters to the north of the main spring. During August–October 1999, several field trips were conducted in the vicinity of Anderson Springs to continue monitoring and sampling the thermal manifestations. The new fumarolic area had increased in temperature and in discharge intensity since 1998, and a zone of dead trees had developed on the steep bank directly west of the fumaroles. Ground temperatures and diffuse flow of CO2 flow through soils were measured in the area surrounding the main spring and new fumaroles and in the zone of tree-kill.

Janik, C.J.; Goff, F.; Sorey, M.L.; Rytuba, J.J.; Counce, D.; Colvard, E.M.; Huebner, M.; White, L.D.; Foster, A.

1999-01-01

387

Termination of typical wave-function multifractal spectra at the Anderson metal-insulator transition: Field theory description using the functional renormalization group  

NASA Astrophysics Data System (ADS)

We revisit the problem of wave-function statistics at the Anderson metal-insulator transition (MIT) of noninteracting electrons in d>2 spatial dimensions. At the transition, the complex spatial structure of the critical wave functions is reflected in the nonlinear behavior of the multifractal spectrum of generalized inverse participation ratios (IPRs). Beyond the crossover from narrow to broad IPR statistics, which always occurs for sufficiently large moments of the wave-function amplitude, the spectrum obtained from a typical wave function associated with a particular disorder realization differs markedly from that obtained from the disorder-averaged IPRs. This phenomenon is known as the termination of the multifractal spectrum. We provide a field theoretical derivation for the termination of the typical multifractal spectrum by combining the nonlinear sigma model framework, conventionally used to access the MIT in d=2+? dimensions, with a functional renormalization-group (FRG) technique. The FRG method deployed here was originally pioneered to study the properties of the two-dimensional (2D) random-phase XY model [D. Carpentier and P. Le Doussal, Nucl. Phys. B 588, 565 (2000)]. The same method was used to demonstrate the termination of the multifractal spectrum in the very special problem of 2D Dirac fermions subject to a random Abelian vector potential. Our result shows that the typical multifractal wave-function spectrum and its termination can be obtained at a generic Anderson localization transition in d>2 , within the standard field theoretical framework of the nonlinear sigma model, when combined with the FRG.

Foster, Matthew S.; Ryu, Shinsei; Ludwig, Andreas W. W.

2009-08-01

388

BROADBAND EXCITATION IN NUCLEAR MAGNETIC RESONANCE  

SciTech Connect

Theoretical methods for designing sequences of radio frequency (rf) radiation pulses for broadband excitation of spin systems in nuclear magnetic resonance (NMR) are described. The sequences excite spins uniformly over large ranges of resonant frequencies arising from static magnetic field inhomogeneity, chemical shift differences, or spin couplings, or over large ranges of rf field amplitudes. Specific sequences for creating a population inversion or transverse magnetization are derived and demonstrated experimentally in liquid and solid state NMR. One approach to broadband excitation is based on principles of coherent averaging theory. A general formalism for deriving pulse sequences is given, along with computational methods for specific cases. This approach leads to sequences that produce strictly constant transformations of a spin system. The importance of this feature in NMR applications is discussed. A second approach to broadband excitation makes use of iterative schemes, i.e. sets of operations that are applied repetitively to a given initial pulse sequences, generating a series of increasingly complex sequences with increasingly desirable properties. A general mathematical framework for analyzing iterative schemes is developed. An iterative scheme is treated as a function that acts on a space of operators corresponding to the transformations produced by all possible pulse sequences. The fixed points of the function and the stability of the fixed points are shown to determine the essential behavior of the scheme. Iterative schemes for broadband population inversion are treated in detail. Algebraic and numerical methods for performing the mathematical analysis are presented. Two additional topics are treated. The first is the construction of sequences for uniform excitation of double-quantum coherence and for uniform polarization transfer over a range of spin couplings. Double-quantum excitation sequences are demonstrated in a liquid crystal system. The second additional topic is the construction of iterative schemes for narrowband population inversion. The use of sequences that invert spin populations only over a narrow range of rf field amplitudes to spatially localize NMR signals in an rf field gradient is discussed.

Tycko, R.

1984-10-01

389

Temperature and excitable cells  

PubMed Central

Temperature affects a host of biological processes, one of which is the conduction velocity of action potentials (AP). The velocity-temperature profile of APs has remained remarkably conserved across excitable animal and plant cells. Herein, we will not analyze this behavior in terms of temperature sensitivities of single molecules (e.g., ion channels), but rather we present a phenomenological thermodynamic interpretation. By assuming that APs are acoustic phenomena, one arrives at testable predictions about the temperature-dependence of the macroscopic material properties of the excitable cell membrane. These material properties set constraints on the excitability of a cell membrane and allow us to hypothesize about its typical relaxation timescales. The presented approach—by virtue of its thermodynamic nature—is by no means limited to temperature. It applies equally well to all thermodynamic variables (e.g., mechanical stretch, pH, ion concentrations, etc.) and to underline this argument we discuss some implications and predictions for sensory physiology. PMID:24563710

Fillafer, Christian; Schneider, Matthias F

2013-01-01

390

Pulse excitation of bolometer bridges  

NASA Technical Reports Server (NTRS)

Driving bolometer bridge by appropriately phased excitation pulses increases signal-to-noise ratio of bolometer sensor which operates on a chopped light beam. Method allows higher applied voltage than is possible by conventional ac or dc excitation.

Rusk, S. J.

1972-01-01

391

Apparatus for photon excited catalysis  

NASA Technical Reports Server (NTRS)

An apparatus is described for increasing the yield of photonically excited gas phase reactions by extracting excess energy from unstable, excited species by contacting the species with the surface of a finely divided solid.

Saffren, M. M. (inventor)

1977-01-01

392

Localization for Random Unitary Operators  

E-print Network

We consider unitary analogs of $1-$dimensional Anderson models on $l^2(\\Z)$ defined by the product $U_\\omega=D_\\omega S$ where $S$ is a deterministic unitary and $D_\\omega$ is a diagonal matrix of i.i.d. random phases. The operator $S$ is an absolutely continuous band matrix which depends on a parameter controlling the size of its off-diagonal elements. We prove that the spectrum of $U_\\omega$ is pure point almost surely for all values of the parameter of $S$. We provide similar results for unitary operators defined on $l^2(\\N)$ together with an application to orthogonal polynomials on the unit circle. We get almost sure localization for polynomials characterized by Verblunski coefficients of constant modulus and correlated random phases.

Eman Hamza; Alain Joye; Gunter Stolz

2005-04-25

393

Causation's nuclear future: applying proportional liability to the Price-Anderson Act.  

PubMed

For more than a quarter century, public discourse has pushed the nuclear-power industry in the direction of heavier regulation and greater scrutiny, effectively halting construction of new reactors. By focusing on contemporary fear of significant accidents, such discourse begs the question of what the nation's court system would actually do should a major nuclear incident cause radiation-induced cancers. Congress's attempt to answer that question is the Price-Anderson Act, a broad statute addressing claims by the victims of a major nuclear accident. Lower courts interpreting the Act have repeatedly encountered a major stumbling block: it declares that judges must apply the antediluvian preponderance-of-the-evidence logic of state tort law, even though radiation science insists that the causes of radiation-induced cancers are more complex. After a major nuclear accident, the Act's paradoxically outdated rules for adjudicating "causation" would make post-incident compensation unworkable. This Note urges that nuclear-power-plant liability should not turn on eighteenth-century tort law. Drawing on modern scientific conclusions regarding the invariably "statistical" nature of cancer, this Note suggests a unitary federal standard for the Price-Anderson Act--that a defendant be deemed to have "caused" a plaintiff's injury in direct proportion to the increased risk of harm the defendant has imposed. This "proportional liability" rule would not only fairly evaluate the costs borne by injured plaintiffs and protect a reawakening nuclear industry from the prospect of bank-breaking litigation, but would prove workable with only minor changes to the Price-Anderson Act's standards of "injury" and "fault." PMID:25507406

O'Connell, William D

2014-11-01

394

Causation's nuclear future: applying proportional liability to the Price-Anderson Act.  

PubMed

For more than a quarter century, public discourse has pushed the nuclear-power industry in the direction of heavier regulation and greater scrutiny, effectively halting construction of new reactors. By focusing on contemporary fear of significant accidents, such discourse begs the question of what the nation's court system would actually do should a major nuclear incident cause radiation-induced cancers. Congress's attempt to answer that question is the Price-Anderson Act, a broad statute addressing claims by the victims of a major nuclear accident. Lower courts interpreting the Act have repeatedly encountered a major stumbling block: it declares that judges must apply the antediluvian preponderance-of-the-evidence logic of state tort law, even though radiation science insists that the causes of radiation-induced cancers are more complex. After a major nuclear accident, the Act's paradoxically outdated rules for adjudicating "causation" would make post-incident compensation unworkable. This Note urges that nuclear-power-plant liability should not turn on eighteenth-century tort law. Drawing on modern scientific conclusions regarding the invariably "statistical" nature of cancer, this Note suggests a unitary federal standard for the Price-Anderson Act--that a defendant be deemed to have "caused" a plaintiff's injury in direct proportion to the increased risk of harm the defendant has imposed. This "proportional liability" rule would not only fairly evaluate the costs borne by injured plaintiffs and protect a reawakening nuclear industry from the prospect of bank-breaking litigation, but would prove workable with only minor changes to the Price-Anderson Act's standards of "injury" and "fault." PMID:25423683

O'Connell, William D

2014-11-01

395

Hydrothermal assembly and luminescence property of lanthanide-containing Anderson polyoxometalates  

SciTech Connect

Two compounds, {l_brace}[Sm(H{sub 2}O){sub 5}]{sub 2}(TeMo{sub 6}O{sub 24}){r_brace}.6H{sub 2}O (1) and {l_brace}[Eu(H{sub 2}O){sub 7}]{sub 2} (TeMo{sub 6}O{sub 24}){r_brace}.5H{sub 2}O (2) have been synthesized by hydrothermal reactions and characterized by elemental analyses, IR spectra, thermal stability analyses, X-ray powder diffraction, and single-crystal X-ray diffraction. Compound 1 represents the first example of a 2D layer architecture constructed from Anderson-type polyoxoanions [TeMo{sub 6}O{sub 24}]{sup 6-} and rare-earth ions Ln{sup 3+}. Compound 2 displays a 1D chain structure built up of alternating Anderson-type polyoxoanions [TeMo{sub 6}O{sub 24}]{sup 6-} and rare-earth ions Eu{sup 3+} along the c-axis. Luminescence measurement of 2 exhibits typical red fluorescent emission of the Eu{sup 3+} ion at room temperature. Furthermore, the emission is intense enough to be observed macroscopically under UV irradiation (365 nm). - Graphical abstract: Two compounds based on Anderson-type polyoxoanion building blocks and rare-earth ions have been synthesized under hydrothermal conditions. Compound 1 exhibits a 2D layer architecture constructed from [TeMo{sub 6}O{sub 24}]{sup 6-} anions and rare-earth ions Ln{sup 3+}. Compound 2 displays a 1D chain structure and possesses the intense luminescence property.

Liu Ying [Key Laboratory of Polyoxometalates Science of Ministry of Education, College of Chemistry, Northeast Normal University, Changchun City, JiLin 130024 (China); Liu Shuxia [Key Laboratory of Polyoxometalates Science of Ministry of Education, College of Chemistry, Northeast Normal University, Changchun City, JiLin 130024 (China)], E-mail: liusx@nenu.edu.cn; Cao Ruige; Ji Hongmei; Zhang Shiwei; Ren Yuanhang [Key Laboratory of Polyoxometalates Science of Ministry of Education, College of Chemistry, Northeast Normal University, Changchun City, JiLin 130024 (China)

2008-09-15

396

Machine learning for many-body physics: The case of the Anderson impurity model  

NASA Astrophysics Data System (ADS)

Machine learning methods are applied to finding the Green's function of the Anderson impurity model, a basic model system of quantum many-body condensed-matter physics. Different methods of parametrizing the Green's function are investigated; a representation in terms of Legendre polynomials is found to be superior due to its limited number of coefficients and its applicability to state of the art methods of solution. The dependence of the errors on the size of the training set is determined. The results indicate that a machine learning approach to dynamical mean-field theory may be feasible.

Arsenault, Louis-François; Lopez-Bezanilla, Alejandro; von Lilienfeld, O. Anatole; Millis, Andrew J.

2014-10-01

397

Data Center Energy Efficiency and Renewable Energy Site Assessment: Anderson Readiness Center; Salem, Oregon  

SciTech Connect

This report summarizes the results from the data center energy efficiency and renewable energy site assessment conducted for the Oregon Army National Guard in Salem, Oregon. A team led by NREL conducted the assessment of the Anderson Readiness Center data centers March 18-20, 2014 as part of ongoing efforts to reduce energy use and incorporate renewable energy technologies where feasible. Although the data centers in this facility account for less than 5% of the total square footage, they are estimated to be responsible for 70% of the annual electricity consumption.

Metzger, I.; Van Geet, O.

2014-06-01

398

MD Anderson study finds depression and shortened telomeres increase bladder cancer mortality  

Cancer.gov

The combination of shortened telomeres, a biological marker of aging associated with cancer development, and elevated depression significantly impacted bladder cancer mortality, according to data presented at the 11th Annual AACR International Conference on Frontiers in Cancer Prevention Research. As part of an ongoing, large-scale epidemiologic study of bladder cancer, researchers from the MD Anderson Cancer Center in Houston collected clinical and mental health information on 464 patients with bladder cancer. They assessed patients' depression levels with the Center for Epidemiologic Studies Depression Scale.

399

Anisotropic behavior of quantum transport in graphene superlattices: Coexistence of ballistic conduction with Anderson insulating regime  

NASA Astrophysics Data System (ADS)

We report on the possibility to generate highly anisotropic quantum conductivity in disordered graphene-based superlattices. Our quantum simulations, based on an efficient real-space implementation of the Kubo-Greenwood formula, show that in disordered graphene superlattices the strength of multiple scattering phenomena can strongly depend on the transport measurement geometry. This eventually yields the coexistence of a ballistic waveguide and a highly resistive channel (Anderson insulator) in the same two-dimensional platform, evidenced by a ?yy/?xx ratio varying over several orders of magnitude, and suggesting the possibility of building graphene electronic circuits based on the unique properties of chiral massless Dirac fermions in graphene.

Pedersen, Jesper Goor; Cummings, Aron W.; Roche, Stephan

2014-04-01

400

MD Anderson study finds blood vessel cells coax colorectal cancer cells into more dangerous state  

Cancer.gov

Blood vessels that supply oxygen and nutrients to tumors can also deliver something else -- a signal that strengthens nearby cancer cells, making them more resistant to chemotherapy, more likely to spread to other organs and more lethal, scientists at The University of Texas MD Anderson Cancer Center report online in Cancer Cell. Working in human colorectal cancer cell lines and tumor samples, as well as mouse models, the researchers found that endothelial cells, which line the inside of blood vessels, can trigger changes in cancer cells without even coming into direct contact with them.

401

MD Anderson study finds metabolic protein launches sugar feast that nurtures brain tumors  

Cancer.gov

Researchers at The University of Texas MD Anderson Cancer Center have tracked down a cancer-promoting protein's pathway into the cell nucleus and discovered how, once there, it fires up a glucose metabolism pathway on which brain tumors thrive. They also found a vital spot along the protein's journey that can be attacked with a type of drug not yet deployed against glioblastoma multiforme, the most common and lethal form of brain cancer. Published online by Nature Cell Biology, the paper further illuminates the importance of pyruvate kinase M2 (PKM2) in cancer development and progression.

402

MD Anderson study finds link between statins and improved survival in inflammatory breast cancer  

Cancer.gov

Researchers from The University of Texas MD Anderson Cancer Center found statins, the commonly used drug to lower cholesterol, improved progression-free survival in patients with inflammatory breast cancer (IBC). The retrospective study was presented in a poster discussion at the 2012 CTRC-AACR San Antonio Breast Cancer Symposium and follows a previously reported Danish study indicating there is some evidence to suggest the anti-inflammatory properties of statins could reduce the risk of breast cancer recurrence. Still, the overall effects of statins have not been examined in relation to IBC.

403

Disorder in Quantum Vacuum: Casimir-Induced Localization of Matter Waves  

SciTech Connect

Disordered geometrical boundaries such as rough surfaces induce important modifications to the mode spectrum of the electromagnetic quantum vacuum. In analogy to Anderson localization of waves induced by a random potential, here we show that the Casimir-Polder interaction between a cold atomic sample and a rough surface also produces localization phenomena. These effects, that represent a macroscopic manifestation of disorder in quantum vacuum, should be observable with Bose-Einstein condensates expanding in proximity of rough surfaces.

Moreno, G. A. [IFIBA-Departamento de Fisica, FCEyN, UBA, Ciudad Universitaria, 1428 Buenos Aires (Argentina); Theoretical Division, MS B213, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Messina, R. [Laboratoire Kastler Brossel, case 74, CNRS, ENS, UPMC, Campus Jussieu, F-75252 Paris Cedex 05 (France); SYRTE--Observatoire de Paris 61, avenue de l'Observatoire, F-75014 Paris (France); Dalvit, D. A. R. [Theoretical Division, MS B213, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Lambrecht, A.; Reynaud, S. [Laboratoire Kastler Brossel, case 74, CNRS, ENS, UPMC, Campus Jussieu, F-75252 Paris Cedex 05 (France); Maia Neto, P. A. [Instituto de Fisica, UFRJ, CP 68528, Rio de Janeiro, RJ, 21941-972 (Brazil)

2010-11-19

404

Disorder in quantum vacuum: Casimir-induced localization of matter waves.  

PubMed

Disordered geometrical boundaries such as rough surfaces induce important modifications to the mode spectrum of the electromagnetic quantum vacuum. In analogy to Anderson localization of waves induced by a random potential, here we show that the Casimir-Polder interaction between a cold atomic sample and a rough surface also produces localization phenomena. These effects, that represent a macroscopic manifestation of disorder in quantum vacuum, should be observable with Bose-Einstein condensates expanding in proximity of rough surfaces. PMID:21231273

Moreno, G A; Messina, R; Dalvit, D A R; Lambrecht, A; Maia Neto, P A; Reynaud, S

2010-11-19

405

Propagation failure of excitation waves on trees and random networks  

NASA Astrophysics Data System (ADS)

Excitation waves are studied on trees and random networks of coupled active elements. Undamped propagation of such waves is observed in those networks. It represents an excursion from the resting state and a relaxation back to it for each node. However, the degrees of the nodes influence drastically the dynamics. Excitation propagates more slowly through nodes with larger degrees and beyond some critical degree waves lose their stability and disappear. For regular trees with a fixed branching ratio, the critical degree is determined with an approximate analytical theory which also holds locally for the early stage of excitation spreading in random networks.

Kouvaris, Nikos E.; Isele, Thomas; Mikhailov, Alexander S.; Schöll, Eckehard

2014-06-01

406

Anderson-Gruneisen parameter under high temperature in (Fe,Mn,Co,Mg)2SiO4  

NASA Astrophysics Data System (ADS)

The Anderson-Grüneisen parameter (?) is of considerable importance to Earth scientists because it sets limitations on the thermo-elastic properties of the lower mantle and core. However, there are several formulations on the Grüneisen parameter, which are in frequent use and predict varying dependence of d as a function of temperature. In this paper, the expressions for thermal expansion, thermal expansion coefficients and bulk modulus are obtained considering the anharmonic dependence on temperature and are applied to study these constants to (Fe,Mn,Co,Mg)2SiO4. Using the derived expressions, we have shown that different parameters on which the Anderson-Grüneisen parameter (?) depends are temperature dependent, but above all the Anderson-Grüneisen parameter (?) is independent of temperature. The results obtained have been found to be comparable to experimental data.

Gupta, S.; Goyal, S. C.

2012-07-01

407

Extending single molecule fluorescence observation time by amplitude-modulated excitation.  

PubMed

We present a hardware-based method that can improve single molecule fluorophore observation time by up to 1500% and super-localization by 47% for the experimental conditions used. The excitation was modulated using an acousto-optic modulator (AOM) synchronized to the data acquisition and inherent data conversion time of the detector. The observation time and precision in super-localization of four commonly used fluorophores were compared under modulated and traditional continuous excitation, including direct total internal reflectance excitation of Alexa 555 and Cy3, non-radiative Förster resonance energy transfer (FRET) excited Cy5, and direct epi-fluorescence wide field excitation of Rhodamine 6G. The proposed amplitude-modulated excitation does not perturb the chemical makeup of the system or sacrifice signal and is compatible with multiple types of fluorophores. Amplitude-modulated excitation has practical applications for any fluorescent study utilizing an instrumental setup with time-delayed detectors. PMID:24587894

Kisley, Lydia; Chang, Wei-Shun; Cooper, David; Mansur, Andrea P; Landes, Christy F

2013-09-01

408

Extending single molecule fluorescence observation time by amplitude-modulated excitation  

PubMed Central

We present a hardware-based method that can improve single molecule fluorophore observation time by up to 1500% and super-localization by 47% for the experimental conditions used. The excitation was modulated using an acousto-optic modulator (AOM) synchronized to the data acquisition and inherent data conversion time of the detector. The observation time and precision in super-localization of four commonly used fluorophores were compared under modulated and traditional continuous excitation, including direct total internal reflectance excitation of Alexa 555 and Cy3, non-radiative Förster resonance energy transfer (FRET) excited Cy5, and direct epi-fluorescence wide field excitation of Rhodamine 6G. The proposed amplitude-modulated excitation does not perturb the chemical makeup of the system or sacrifice signal and is compatible with multiple types of fluorophores. Amplitude-modulated excitation has practical applications for any fluorescent study utilizing an instrumental setup with time-delayed detectors. PMID:24587894

Kisley, Lydia; Chang, Wei-Shun; Cooper, David; Mansur, Andrea P; Landes, Christy F

2014-01-01

409

Strong correlation induced charge localization in antiferromagnets  

PubMed Central

The fate of a hole injected in an antiferromagnet is an outstanding issue of strongly correlated physics. It provides important insights into doped Mott insulators closely related to high-temperature superconductivity. Here, we report a systematic numerical study of t-J ladder systems based on the density matrix renormalization group. It reveals a surprising result for the single hole's motion in an otherwise well-understood undoped system. Specifically, we find that the common belief of quasiparticle picture is invalidated by the self-localization of the doped hole. In contrast to Anderson localization caused by disorders, the charge localization discovered here is an entirely new phenomenon purely of strong correlation origin. It results from destructive quantum interference of novel signs picked up by the hole, and since the same effect is of a generic feature of doped Mott physics, our findings unveil a new paradigm which may go beyond the single hole doped system. PMID:24002668

Zhu, Zheng; Jiang, Hong-Chen; Qi, Yang; Tian, Chushun; Weng, Zheng-Yu

2013-01-01

410

ANDERSON-TEIXEIRA FINAL PROOF.DOCX (DO NOT DELETE) 3/7/2011 9:29 AM DO BIOFUELS LIFE CYCLE  

E-print Network

ANDERSON-TEIXEIRA FINAL PROOF.DOCX (DO NOT DELETE) 3/7/2011 9:29 AM 589 DO BIOFUELS LIFE CYCLE ANALYSES ACCURATELY QUANTIFY THE CLIMATE IMPACTS OF BIOFUELS-RELATED LAND USE CHANGE? Kristina J. Anderson in determining the sustainability of biofuels. To ensure that legal standards are effective in limiting climate

DeLucia, Evan H.

411

Anderson-Mott transition in arrays of a few dopant atoms in a silicon transistor.  

PubMed

Dopant atoms are used to control the properties of semiconductors in most electronic devices. Recent advances such as single-ion implantation have allowed the precise positioning of single dopants in semiconductors as well as the fabrication of single-atom transistors, representing steps forward in the realization of quantum circuits. However, the interactions between dopant atoms have only been studied in systems containing large numbers of dopants, so it has not been possible to explore fundamental phenomena such as the Anderson-Mott transition between conduction by sequential tunnelling through isolated dopant atoms, and conduction through thermally activated impurity Hubbard bands. Here, we observe the Anderson-Mott transition at low temperatures in silicon transistors containing arrays of two, four or six arsenic dopant atoms that have been deterministically implanted along the channel of the device. The transition is induced by controlling the spacing between dopant atoms. Furthermore, at the critical density between tunnelling and band transport regimes, we are able to change the phase of the electron system from a frozen Wigner-like phase to a Fermi glass by increasing the temperature. Our results open up new approaches for the investigation of coherent transport, band engineering and strongly correlated systems in condensed-matter physics. PMID:22751223

Prati, Enrico; Hori, Masahiro; Guagliardo, Filippo; Ferrari, Giorgio; Shinada, Takahiro

2012-07-01

412

Neurosurgical oncology at the university of Texas M. D. Anderson Cancer Center: its genesis and evolution.  

PubMed

The practice of neurosurgery at The University of Texas M. D. Anderson Cancer Center began in 1944 with one neurosurgeon among the 11 physicians present in a makeshift 16-room outpatient clinic at a temporary location. Neurosurgical oncology evolved as the hospital did, first as a neurosurgery service in 1951, then as the Section of Neurosurgery within the Department of Head and Neck Surgery in 1979, and finally, as the Department of Neurosurgery in 1990. Although M. D. Anderson is now one of the largest institutions in the world devoted exclusively to cancer patient care, research, education, and prevention, it has an unusual history, which is reviewed in terms of the institution's origin in 1941, its development under three presidents, and its fostering of neurosurgical oncology. We chronicle the growth and development of the department from 1990 to 2003 and describe the unique opportunities it presents for surgical innovation, for clinical and basic research, for training residents and fellows, and for multidisciplinary collaboration in neurosurgical oncology. PMID:15792524

Lang, Frederick F; Wildrick, David M; DeMonte, Franco; Sawaya, Raymond

2005-04-01

413

Two new architectures based on Anderson-type polyoxoanions and cadmium fragments  

NASA Astrophysics Data System (ADS)

Two new hybrid compounds with cadmium cations/coordination complexes as linkers, (C 6H 5NO 2) 4[(H 2O) 14Cd 3(CrMo 6H 6O 24) 2] 1 (C 6H 5NO 2 = pyridine-4-carboxylic acid) and H[(H 2O) 2(C 6H 5NO 2)(C 6H 4NO 2)Cd] 2[CrMo 6H 6O 24]·9H 2O 2 (C 6H 5NO 2, C 6H 4NO 2 = pyridine-3-carboxylic acid), have been synthesized and characterized by elemental analyses, IR, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in the polar space group Pc and is made up of [CrMo 6H 6O 24] 3- polyoxoanions covalently linked by cadmium cations to yield an unprecedented one-dimensional chain, which represents the first example of one-dimensional assemblies based on Anderson-type POMs and cadmium cations. Adjacent inorganic chains are further in close contact by pyridine-4-carboxylic acid glues to form three-dimensional supramolecular polar networks via strong hydrogen-bonding interactions. Compound 2 exhibits a three-dimensional supramolecular channel framework constructed from cationic cadmium-pyridine-3-carboxylic acid coordination polymer sheets pillared by Anderson-type polyoxoanions, with dissociated water molecules situated in the channels. Furthermore, both of the compounds exhibit photoluminescent properties at ambient temperature.

An, Haiyan; Xu, Tieqi; Jia, Cuiying; Zheng, Hui; Mu, Wensheng

2009-09-01

414

Excitability in Dictyostelium development  

NASA Astrophysics Data System (ADS)

Discovering how populations of cells reliably develop into complex multi-cellular structures is a key challenge in modern developmental biology. This requires an understanding of how networks at the single-cell level, when combined with intercellular signaling and environmental cues, give rise to the collective behaviors observed in cellular populations. I will present work in collaboration with the Gregor lab, showing that the signal-relay response of starved cells of the amoebae Dictyostelium discoideum can be well modeled as an excitable system. This is in contrast to existing models of the network that postulate a feed-forward cascade. I then extend the signal-relay model to describe how spatial gradient sensing may be achieved via excitability. One potential advantage of relying on feedback for gradient sensing is in preventing ``cheaters'' that do not produce signals from taking over the population. I then combine these models of single-cell signaling and chemotaxis to perform large-scale agent-based simulations of aggregating populations. This allows direct study of how variations in single-cell dynamics modify population behavior. In order to further test this model, I use the results of a screen for mutant cell lines that exhibit altered collective patterns. Finally, I use an existing FRET movie database of starved cell populations at varying cell densities and dilution rates to study heterogeneity in repeated spatio-temporal activity patterns.

Schwab, David

2013-03-01

415

Excitation energies of molecules within time-independent density functional theory  

SciTech Connect

Recently proposed exchange energy functional for excited-states is tested for obtaining excitation energies of diatomic molecules. The functional is the ground-state counterpart of the local-density approximation, the modified local spin density (MLSD). The MLSD functional is tested for the N{sub 2} and CO diatomic molecules. The excitation energy obtained with the MLSD functional for the N{sub 2} molecule is in close vicinity to that obtained from the exact exchange orbital functional, Krieger, Li and Iafrate (KLI). For the CO molecule, the departure in excitation energy is observed and is due to the overcorrection of self-interaction.

Hemanadhan, M., E-mail: hemanadh@iitk.ac.in; Harbola, Manoj K., E-mail: hemanadh@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur, Kanpur-208016 (India)

2014-04-24

416

Parity-dependent localization in N strongly coupled chains  

NASA Astrophysics Data System (ADS)

Anderson localization of wave functions at zero energy in quasi-one-dimensional (1D) systems of N disordered chains with interchain coupling t is examined. Localization becomes weaker than for the 1D disordered chain (t =0) when t is smaller than the longitudinal hopping t'=1, and localization becomes usually much stronger when t ?t'. This is not so for all N. We find "immunity" to strong localization for open (periodic) lateral boundary conditions when N is odd (a multiple of 4), with localization that is weaker than for t =0 and rather insensitive to t when t ?t'. The peculiar N dependence and a critical scaling with N are explained by a perturbative treatment in t'/t, and the correspondence to a weakly disordered effective chain is shown. Our results could be relevant for experimental studies of localization in photonic waveguide arrays.

Weinmann, Dietmar; Evangelou, S. N.

2014-10-01

417

Localization of a matter wave packet in a disordered potential  

SciTech Connect

We theoretically study the Anderson localization of a matter wave packet in a one-dimensional disordered potential. We develop an analytical model which includes the initial phase-space density of the matter wave and the spectral broadening induced by the disorder. Our approach predicts a behavior of the localized density profile significantly more complex than a simple exponential decay. These results are confirmed by large-scale and long-time numerical calculations. They shed new light on recent experiments with ultracold atoms and may impact their analysis.

Piraud, M.; Bouyer, P.; Aspect, A.; Sanchez-Palencia, L. [Laboratoire Charles Fabry de l'Institut d'Optique, CNRS and Univ. Paris-Sud, Campus Polytechnique, RD 128, F-91127 Palaiseau cedex (France); Lugan, P. [Laboratoire Charles Fabry de l'Institut d'Optique, CNRS and Univ. Paris-Sud, Campus Polytechnique, RD 128, F-91127 Palaiseau cedex (France); Physikalisches Institut, Albert-Ludwigs-Universitaet, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany)

2011-03-15

418

The distribution of localization centers in some discrete random systems  

E-print Network

As a supplement of our previous work, we consider the localized region of the random Schroedinger operators on $l^2({\\bf Z}^d)$ and study the point process composed of their eigenvalues and corresponding localization centers. For the Anderson model, we show that, this point process in the natural scaling limit converges in distribution to the Poisson process on the product space of energy and space. In other models with suitable Wegner-type bounds, we can at least show that any limiting point processes are infinitely divisible.

Fumihiko Nakano

2012-10-16

419

Fusion excitation function revisited  

E-print Network

We report on a comprehensive systematics of fusion-evaporation and/or fusion-fission cross sections for a very large variety of systems over an energy range 4-155 A.MeV. Scaled by the reaction cross sections, fusion cross sections do not show a universal behavior valid for all systems although a high degree of correlation is present when data are ordered by the system mass asymmetry.For the rather light and close to mass-symmetric systems the main characteristics of the complete and incomplete fusion excitation functions can be precisely determined. Despite an evident lack of data above 15A.MeV for all heavy systems the available data suggests that geometrical effects could explain the persistence of incomplete fusion at incident energies as high as 155A.MeV.

Ph. Eudes; Z. Basrak; F. Sébille; V. de la Mota; G. Royer; M. Zori?

2012-09-28

420

STUDIES OF EXCITABLE MEMBRANES  

PubMed Central

The neuromuscular junctions and nonjunctional sarcolemmas of mammalian skeletal muscle fibers were studied by conventional thin-section electron microscopy and freeze-fracture techniques. A modified acetylcholinesterase staining procedure that is compatible with light microscopy, conventional thin-section electron microscopy, and freeze-fracture techniques is described. Freeze-fracture replicas were utilized to visualize the internal macromolecular architecture of the nerve terminal membrane, the chemically excitable neuromuscular junction postsynaptic folds, and the electrically excitable nonjunctional sarcolemma. The nerve terminal membrane is characterized by two parallel rows of 100–110-Å particles which may be associated with synpatic vesicle fusion and release. On the postsynpatic folds, irregular rows of densely packed 110–140-Å particles were observed and evidence is assembled which indicates that these large transmembrane macromolecules may represent the morphological correlate for functional acetylcholine receptor activity in mammalian motor endplates. Differences in the size and distribution of particles in mammalian as compared with amphibian and fish postsynaptic junctional membranes are correlated with current biochemical and electron micrograph autoradiographic data. Orthogonal arrays of 60-Å particles were observed in the split postsynaptic sarcolemmas of many diaphragm myofibers. On the basis of differences in the number and distribution of these "square" arrays within the sarcolemmas, two classes of fibers were identified in the diaphragm. Subsequent confirmation of the fiber types as fast- and slow-twitch fibers (Ellisman et al. 1974. J. Cell Biol. 63[2, Pt. 2]:93 a. [Abstr.]) may indicate a possible role for the square arrays in the electrogenic mechanism. Experiments in progress involving specific labeling techniques are expected to permit positive identification of many of these intriguing transmembrane macromolecules. PMID:4138515

Rash, John E.; Ellisman, Mark H.

1974-01-01

421

Optically excited states in positronium  

NASA Technical Reports Server (NTRS)

Optical excitation are reported of the 1 3S-2 3P transition in positronium, and a second excitation from n=2 to higher n states. The experiment used light from two pulsed dye lasers. Changes in the positronium annihilation rate during and after the laser pulse were used to deduce the excited state populations. The n=2 level was found to be saturable and excitable to a substantial fraction of n=2 positronium to higher levels. Preliminary spectroscopic measurements were performed on n=14 and n=15 positronium.

Howell, R. H.; Ziock, Klaus P.; Magnotta, F.; Dermer, Charles D.; Failor, R. A.; Jones, K. M.

1990-01-01

422

Program Spotlight: University of Puerto Rico and MD Anderson Partnership Welcomes Its First Graduates, Dedicated to Researching Cancer Health Disparities  

Cancer.gov

CRCHD joins the Principal Investigators and Diversity Training co-leaders of the University of Puerto Rico and the University of Texas MD Anderson Cancer Center U54 Partnership for Excellence in Cancer Research in congratulating its first MDPhD graduates Sergei Gumá-de La Vega and Nahir Cortés-Santiago.

423

MD Anderson researchers find that the number of younger patients with newly diagnosed colorectal cancer may nearly double by 2030  

Cancer.gov

In the next 15 years, more than one in 10 colon cancers and nearly one in four rectal cancers will be diagnosed in patients younger than the traditional screening age, according to researchers at The University of Texas MD Anderson Cancer Center.

424

COMBINATORIAL PROOFS OF FERMAT'S, LUCAS'S, AND WILSON'S PETER G. ANDERSON, ARTHUR T. BENJAMIN, AND JEREMY A. ROUSE  

E-print Network

COMBINATORIAL PROOFS OF FERMAT'S, LUCAS'S, AND WILSON'S THEOREMS PETER G. ANDERSON, ARTHUR T case where b = 0, it is clear that Vp = ap . Consequently, we have Fermat's Theorem: If p is a prime, then ap a (mod p). This combinatorial proof of Fermat's theorem was originally given in [2]. Next

Anderson, Peter G.

425

THE BROADER BENEFITS OF TRANSPORTATION INFRASTUCTURE Ian Sue Wing, William P. Anderson and T.R. Lakshmanan  

E-print Network

1 THE BROADER BENEFITS OF TRANSPORTATION INFRASTUCTURE Ian Sue Wing, William P. Anderson and T.R. Lakshmanan Boston University Center for Transportation Studies Abstract Assessments of the economic benefits of transportation infrastructure investments are critical to good policy decisions. At present, most

Wing, Ian Sue

426

Ion-temperature-gradient modes in stellarator geometry (T Rafiq, J Anderson, M Nadeem and M Persson)  

E-print Network

Ion-temperature-gradient modes in stellarator geometry (T Rafiq, J Anderson, M Nadeem and M Persson Göteborg, Sweden) The stability of the ion-temperature gradient mode has been examined in the short radius) effect as well as parallel ion dynamics in the electrostatic limit with Boltzman electrons

427

MD Anderson researchers find that breast cancer patients with BRCA gene are diagnosed almost 8 years earlier than generation before  

Cancer.gov

Women with a deleterious gene mutation are diagnosed with breast cancer almost eight years earlier than relatives of the previous generation who also had the disease and/or ovarian cancer, according to new research from the University of Texas MD Anderson Cancer Center.

428

Background Subtraction and Accessibility Analysis in Evidence Grids Peter Anderson-Sprecher, Reid Simmons, and Daniel Huber  

E-print Network

Background Subtraction and Accessibility Analysis in Evidence Grids Peter Anderson-Sprecher, Reid multiple sensors. Previous attempts at back- ground subtraction within evidence grids either do so prior that must be able to differentiate between occupied and unknown space after background subtraction

Simmons, Reid

429

Nuclear liability insurance: the Price-Anderson reparations system and the claims experience of the nuclear industry  

Microsoft Academic Search

The manner in which the Price-Anderson Law operates to provide reparations is reviewed, and the changes made in the law by Congress in 1975 are outlined. Nuclear liability insurers' response to the Three Mile Island accident is described, including emergency assistance funds advanced to qualified evacuees and the claims and litigations that followed. Other nuclear liability claims that have been

Marrone

1983-01-01

430

MD Anderson study finds SUMO-snipping protein plays crucial role in T and B cell development  

Cancer.gov

When SUMO grips STAT5, a protein that activates genes, it blocks the healthy embryonic development of immune B cells and T cells unless its nemesis breaks the hold, a research team led by scientists at The University of Texas MD Anderson Cancer Center reports in Molecular Cell.

431

MD Anderson preclinical study identifies 'master' proto-oncogene that regulates stress-induced ovarian cancer metastasis  

Cancer.gov

Scientists at The University of Texas MD Anderson Cancer Center have discovered the signaling pathway whereby a master regulator of cancer cell proteins -- known as Src -- leads to ovarian cancer progression when exposed to stress hormones. The researchers report in the current issue of Nature Communications that beta blocker drugs mitigate this effect and reduce cancer deaths by an average of 17 percent.

432

Power-Aware Technology Mapping for LUT-Based FPGAs Jason H. Anderson and Farid N. Najm  

E-print Network

consumption of FPGAs is beneficial as it leads to lower packaging and cooling costs as well as improvesPower-Aware Technology Mapping for LUT-Based FPGAs Jason H. Anderson and Farid N. Najm Department@eecg.toronto.edu, f.najm@utoronto.ca Abstract We present a new power-aware technology mapping technique for LUT

Najm, Farid N.

433

UModelling Leaf Shape Evolution Jotun Hein, Nick Jones, Miltos Tsiantis, James Anderson and John Moriarty. 17.6.2011  

E-print Network

UModelling Leaf Shape Evolution Jotun Hein, Nick Jones, Miltos Tsiantis, James Anderson and John on simple models of shape evolution and their application to leaf shapes. Shape analysis is a well in the Tsiantis group (Piazza et al, 2010; Hay and Tsiantis, 2006). Leaf shape can be described as simple

Goldschmidt, Christina

434

Error Recovery for a Boiler System with OTS PID Controller Tom Anderson, Mei Feng, Steve Riddle, Alexander Romanovsky  

E-print Network

Error Recovery for a Boiler System with OTS PID Controller Tom Anderson, Mei Feng, Steve Riddle-The-Shelf) item. The case study used a Simulink model of a steam boiler system together with an OTS PID in practice, employing software models of the PID controller and the steam boiler system rather than

Newcastle upon Tyne, University of

435

Error Recovery for a Boiler System with OTS PID Controller Tom Anderson, Mei Feng, Steve Riddle, Alexander Romanovsky  

E-print Network

1 Error Recovery for a Boiler System with OTS PID Controller Tom Anderson, Mei Feng, Steve Riddle employing an OTS (Off-The-Shelf) item. The case study used a Simulink model of a steam boiler system, employing software models of the PID controller and the steam boiler system rather than conducting

Newcastle upon Tyne, University of

436

MD Anderson study finds drug combination improves progression-free survival for women with metastatic breast cancer:  

Cancer.gov

In an international Phase III randomized study, everolimus, when combined with the hormonal therapy exemestane, has been shown to dramatically improve progression-free survival for women with metastatic breast cancer, according to research from The University of Texas MD Anderson Cancer Center.

437

Identification and Analysis of Learning Preferences of Mentally Ill Adults in Rehabilitative Psychosocial Therapy at the Anderson Mental Health Center.  

ERIC Educational Resources Information Center

A study identified and analyzed the learning preferences of 17 seriously and chronically mentally ill adults participating in the rehabilitative psychosocial therapy program at the Toxaway Church Site of the Anderson Mental Health Center. Staff perceived as boring and unfocused the traditional treatment approach that relied mainly upon…

Newman, Michael K.

438

Multiple temperature scales of the periodic Anderson model: Slave boson approach  

NASA Astrophysics Data System (ADS)

The thermodynamic and transport properties of intermetallic compounds with Ce, Eu, and Yb ions are discussed using the periodic Anderson model with an infinite correlation between f electrons. At high temperatures, these systems exhibit typical features that can be understood in terms of a single-impurity Anderson or Kondo model with Kondo scale TK . At low temperatures, one often finds a normal state governed by the Fermi liquid (FL) laws with characteristic energy scale T0 . The slave boson solution of the periodic model shows that T0 and TK depend not only on the degeneracy and the splitting of the f states, the number of c and f electrons, and their coupling but also on the shape of the conduction-electrons density of states ( c DOS) in the vicinity of the chemical potential ? . The ratio T0/TK depends on the details of the band structure which makes the crossover between the high- and low-temperature regimes system dependent. We show that the c DOS with a sharp peak close to ? yields T0?TK , which explains the “slow crossover” observed in YbAl3 or YbMgCu4 . The c DOS with a minimum or a pseudogap close to ? yields T0?TK ; this leads to an abrupt transition between the high- and low-temperature regimes, as found in YbInCu4 -like systems. In the case of CeCu2Ge2 and CeCu2Si2 , where T0?TK , we show that the pressure dependence of the T2 coefficient of the electrical resistance, A=?(T)/T2 , and the residual resistance are driven by the change in the degeneracy of the f states. The FL laws obtained for T?T0 explain the correlation between the specific-heat coefficient ?=CV/T and the thermopower slope ?(T)/T or between ? and the resistivity coefficient A . The FL laws also show that the Kadowaki-Woods ratio, RKW=A/?2 , and the ratio q=lim{T?0}?/?T assumes nonuniversal values due to different low-temperature degeneracies of various systems. The correlation effects can invalidate the Wiedemann-Franz law and lead to an enhancement of the thermoelectric figure of merit. They can also enhance (or reduce) the low-temperature response of the periodic Anderson model with respect to the predictions of a single-impurity model with the same high-temperature behavior as the periodic one.

Burdin, S.; Zlati?, V.

2009-03-01

439

Two-photon excited UV fluorescence for protein crystal detection  

PubMed Central

Two-photon excited ultraviolet fluorescence (TPE-UVF) microscopy is explored for sensitive protein-crystal detection as a complement to second-order nonlinear optical imaging of chiral crystals (SONICC). Like conventional ultraviolet fluorescence (UVF), TPE-UVF generates image contrast based on the intrinsic fluorescence of aromatic residues, generally producing higher fluorescence emission within crystals than the mother liquor by nature of the higher local protein concentration. However, TPE-UVF has several advantages over conventional UVF, including (i) insensitivity to optical scattering, allowing imaging in turbid matrices, (ii) direct compatibility with conventional optical plates and windows by using visible light for excitation, (iii) elimination of potentially damaging out-of-plane UV excitation, (iv) improved signal to noise through background reduction from out-of-plane excitation and (v) relatively simple integration into instrumentation developed for SONICC. PMID:21931215

Madden, Jeremy T.; DeWalt, Emma L.; Simpson, Garth J.

2011-01-01

440

Classical mapping for Hubbard operators: Application to the double-Anderson model  

SciTech Connect

A classical Cartesian mapping for Hubbard operators is developed to describe the nonequilibrium transport of an open quantum system with many electrons. The mapping of the Hubbard operators representing the many-body Hamiltonian is derived by using analogies from classical mappings of boson creation and annihilation operators vis-à-vis a coherent state representation. The approach provides qualitative results for a double quantum dot array (double Anderson impurity model) coupled to fermionic leads for a range of bias voltages, Coulomb couplings, and hopping terms. While the width and height of the conduction peaks show deviations from the master equation approach considered to be accurate in the limit of weak system-leads couplings and high temperatures, the Hubbard mapping captures all transport channels involving transition between many electron states, some of which are not captured by approximate nonequilibrium Green function closures.

Li, Bin; Miller, William H. [Department of Chemistry and Kenneth S. Pitzer Center for Theoretical Chemistry, University of California, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Levy, Tal J.; Rabani, Eran [School of Chemistry, The Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv 69978 (Israel)

2014-05-28

441

Classical mapping for Hubbard operators: application to the double-Anderson model.  

PubMed

A classical Cartesian mapping for Hubbard operators is developed to describe the nonequilibrium transport of an open quantum system with many electrons. The mapping of the Hubbard operators representing the many-body Hamiltonian is derived by using analogies from classical mappings of boson creation and annihilation operators vis-à-vis a coherent state representation. The approach provides qualitative results for a double quantum dot array (double Anderson impurity model) coupled to fermionic leads for a range of bias voltages, Coulomb couplings, and hopping terms. While the width and height of the conduction peaks show deviations from the master equation approach considered to be accurate in the limit of weak system-leads couplings and high temperatures, the Hubbard mapping captures all transport channels involving transition between many electron states, some of which are not captured by approximate nonequilibrium Green function closures. PMID:24880265

Li, Bin; Miller, William H; Levy, Tal J; Rabani, Eran

2014-05-28

442

A Cartesian quasi-classical model to nonequilibrium quantum transport: the Anderson impurity model.  

PubMed

We apply the recently proposed quasi-classical approach for a second quantized many-electron Hamiltonian in Cartesian coordinates [B. Li and W. H. Miller, J. Chem. Phys. 137, 154107 (2012)] to correlated nonequilibrium quantum transport. The approach provides accurate results for the resonant level model for a wide range of temperatures, bias, and gate voltages, correcting the flaws of our recently proposed mapping using action-angle variables. When electron-electron interactions are included, a Gaussian function scheme is required to map the two-electron integrals, leading to quantitative results for the Anderson impurity model. In particular, we show that the current mapping is capable of capturing quantitatively the Coulomb blockade effect and the temperature dependence of the current below and above the blockade. PMID:23514468

Li, Bin; Levy, Tal J; Swenson, David W H; Rabani, Eran; Miller, William H

2013-03-14

443

Physical characteristics of the M.D. Anderson Hospital clinical neutron beam.  

PubMed

The physical characteristics of the M.D. Anderson Hospital (MDAH) clinical neutron beam are presented. The central-axis percent depth-dose values are intermediate between a 4 and 6 MV X-ray beam. The build-up curves reach a depth of maximum dose at 1.2 cm and have surface dose values of approximately 30%. Teflon flattening filters are employed to flatten the beam at the depth of the 75% dose level. Two wedges are available for shaping the beam; they are made of Teflon and produce wedge angles of 31 degrees and 45 degrees as defined by the ICRU. Output factors ranged from 0.88 for a 4 x 4 cm field to 1.12 for a 20 x 20 cm field. Tungsten blocks reduced the dose received at Dmax to 25% of the unblocked value but only 52% of the unblocked value at a depth of 22.8 cm. PMID:3141978

Horton, J L; Otte, V A; Schultheiss, T E; Stafford, P M; Sun, T; Zermeno, A

1988-09-01

444

Intrafamilial phenotypic variability in four families with Anderson-Fabry disease.  

PubMed

We analysed the clinical history of 16 hemizygous males affected by Anderson-Fabry Disease, from four families, to verify their intrafamilial phenotypic variability. Seven male patients, ranging from 26 to 61?years of age, died, whereas nine (age range 23-55) are alive. Eleven patients have undergone enzyme replacement therapy (ERT) for a period of 5-10?years. We have found a wide range of intrafamilial phenotypic variability in these families, both in terms of target-organs and severity of the disease. Overall, our findings confirm previous data from the literature showing a high degree of intrafamilial phenotypic variability in patients carrying the same mutation. Furthermore, our results underscore the difficulty in giving accurate prognostic information to patients during genetic counselling, both in terms of rate of disease progression and involvement of different organs, when such prognosis is solely based on the patient's family history. PMID:23980562

Rigoldi, M; Concolino, D; Morrone, A; Pieruzzi, F; Ravaglia, R; Furlan, F; Santus, F; Strisciuglio, P; Torti, G; Parini, R

2014-09-01

445

Leveraging Anderson Acceleration for improved convergence of iterative solutions to transport systems  

NASA Astrophysics Data System (ADS)

In this note we demonstrate that using Anderson Acceleration (AA) in place of a standard Picard iteration can not only increase the convergence rate but also make the iteration more robust for two transport applications. We also compare the convergence acceleration provided by AA to that provided by moment-based acceleration methods. Additionally, we demonstrate that those two acceleration methods can be used together in a nested fashion. We begin by describing the AA algorithm. At this point, we will describe two application problems, one from neutronics and one from plasma physics, on which we will apply AA. We provide computational results which highlight the benefits of using AA, namely that we can compute solutions using fewer function evaluations, larger time-steps, and achieve a more robust iteration.

Willert, Jeffrey; Taitano, William T.; Knoll, Dana

2014-09-01

446

Modified Anderson-Darling Test-Based Target Detector in Non-Homogenous Environments  

PubMed Central

A constant false alarm rate (CFAR) target detector in non-homogenous backgrounds is proposed. Based on K-sample Anderson-Darling (AD) tests, the method re-arranges the reference cells by merging homogenous sub-blocks surrounding the cell under test (CUT) into a new reference window to estimate the background statistics. Double partition test, clutter edge refinement and outlier elimination are used as an anti-clutter processor in the proposed Modified AD (MAD) detector. Simulation results show that the proposed MAD test based detector outperforms cell-averaging (CA) CFAR, greatest of (GO) CFAR, smallest of (SO) CFAR, order-statistic (OS) CFAR, variability index (VI) CFAR, and CUT inclusive (CI) CFAR in most non-homogenous situations. PMID:25177800

Li, Yang; Wei, Yinsheng; Li, Bingfei; Alterovitz, Gil

2014-01-01

447

The Ce 4{ital f} surface shift: A test for the Anderson-impurity Hamiltonian  

SciTech Connect

Evidence is provided of the role of the different hybridization strengths between the surface and the bulk in determining the magnitude of the surface shift for the shallow Ce 4{ital f} levels, with respect to the deeper core levels. This was achieved by comparing the photoemission core levels for a weakly hybridized case (CeAl) to a case of intermediate hybridization ({gamma}-Ce). For CeAl a 4{ital f} surface shift of 0.45 eV was observed, similar to that for the 5{ital p} core level, whereas a smaller (if any) 4{ital f} surface shift was observed for {gamma}-Ce. Model calculations based on the Anderson impurity Hamiltonian are shown to give a correct evaluation of this effect, which can be exploited as a way of testing the results of such a description for the Ce {ital f} states. {copyright} {ital 1996 The American Physical Society.}

Duo, L.; De Rossi, S.; Vavassori, P.; Ciccacci, F. [Istituto Nazionale Fisica della Materia--Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, I-20133 Milano (Italy)] [Istituto Nazionale Fisica della Materia--Dipartimento di Fisica, Politecnico di Milano, piazza Leonardo da Vinci 32, I-20133 Milano (Italy); Olcese, G.L. [Dipartimento di Chimica e Chimica Industriale, Universita di Genova, via Dodecaneso 31, I-16146 Genova (Italy)] [Dipartimento di Chimica e Chimica Industriale, Universita di Genova, via Dodecaneso 31, I-16146 Genova (Italy); Chiaia, G.; Lindau, I. [Department of Synchrotron Radiation Research, Lund University, Soelvegatan 14, S-22362 Lund (Sweden)] [Department of Synchrotron Radiation Research, Lund University, Soelvegatan 14, S-22362 Lund (Sweden)

1996-12-01

448

Decay of a nonlinear impurity in a structured continuum from a nonlinear Fano-Anderson model  

SciTech Connect

The decay dynamics of a nonlinear impurity mode embedded in a linear structured continuum is theoretically investigated in the framework of a nonlinear Fano-Anderson model. A gradient flow dynamics for the survival probability is derived in the Van Hove ({lambda}{sup 2}t) limit by a multiple-scale asymptotic analysis, and the role of nonlinearity on the decay law is discussed. In particular, it is shown that the existence of bound states embedded in the continuum acts as transient trapping states which slow down the decay. The dynamical behavior predicted in the {lambda}{sup 2}t limit is studied in detail for a simple tight-binding one-dimensional lattice model, which may describe electron or photon transport in condensed matter or photonic systems. Numerical simulations of the underlying equations confirm, in particular, the trapping effect in the decay process due to bound states embedded in the continuum.

Longhi, Stefano [Dipartimento di Fisica and Istituto di Fotonica e Nanotecnologie del CNR, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milan (Italy)

2007-05-01

449

Volcanic ash dispersed in the Wyodak-Anderson coal bed, Powder River Basin, Wyoming  

USGS Publications Warehouse

Minerals derived from air-fall volcanic ash were found in two zones in the upper Paleocene Wyodak-Anderson coal bed of the Fort Union Formation in the Powder River Basin of Wyoming, and are the first reported evidence of such volcanic material in this thick (> 20 m) coal bed. The volcanic minerals occur in zones that are not visually obvious because they contain little or no clay. These zones were located by geophysical logs of the boreholes and X-ray radiography of the cores. The zones correspond to two of a series of incremental core samples of the coal bed that have anomalous concentrations of Zr, Ba, Nb, Sr, and P2O5. Two suites of minerals were found in both of the high-density zones. A primary suite (not authigenic) consists of silt-sized quartz grains, biotite, and minor zircon. A minor suite consists of authigenic minerals, including calcite, pyrite, kaolinite, quartz, anatase, barite, and an alumino-phosphate (crandallite?). The original volcanic ash is inferred to have consisted of silica glass containing phenocrysts of quartz, biotite, zircon, and possibly, associated feldspars, pyroxenes, and amphiboles. The glass, as well as the less stable minerals, probably dissolved relatively quickly and contributed to the minor authigenic mineral suite or was removed from the peat as a result of the prevailing hydrologic conditions present in a raised peat formation. This type of volcanic ash suggests that suggests that volcanic material could have rained on the peat; this fallout may have also had a fertilizing effect on the peat by providing nutrients essential for plant growth thus contributing to the thick accumulations of the Wyodak-Anderson bed. Notwithstanding, the presence of these minerals provides evidence for the contribution by volcanic sources to the mineral content of coal, but not as tonsteins. ?? 1991.

Triplehorn, D.M.; Stanton, R.W.; Ruppert, L.F.; Crowley, S.S.

1991-01-01

450

Excited waves in shear layers  

NASA Technical Reports Server (NTRS)

The generation of instability waves in free shear layers is investigated. The model assumes an infinitesimally thin shear layer shed from a semi-infinite plate which is exposed to sound excitation. The acoustical shear layer excitation by a source further away from the plate edge in the downstream direction is very weak while upstream from the plate edge the excitation is relatively efficient. A special solution is given for the source at the plate edge. The theory is then extended to two streams on both sides of the shear layer having different velocities and densities. Furthermore, the excitation of a shear layer in a channel is calculated. A reference quantity is found for the magnitude of the excited instability waves. For a comparison with measurements, numerical computations of the velocity field outside the shear layer were carried out.

Bechert, D. W.

1982-01-01

451

Coherent and Incoherent Excitations of Electron-Doped SrTiO3.  

PubMed

Resonant photoemission at the Ti 2p and O 1s edges on a Nb-doped SrTiO(3) thin film revealed that the coherent state (CS) at the Fermi level (E(F)) had a mainly Ti 3d character whereas the incoherent in-gap state (IGS) positioned approximately 1.5 eV below E(F) had a mixed character of Ti 3d and O 2p states. This indicates that the IGS is formed by a spectral-weight transfer from the CS and subsequent spectral-weight redistribution through d-p hybridization. We discuss the evolution of the excitation spectrum with 3d band filling and rationalize the IGS through a mechanism similar to that proposed by Haldane and Anderson. PMID:18352398

Ishida, Yukiaki; Eguchi, Ritsuko; Matsunami, Masaharu; Horiba, Koji; Taguchi, Munetaka; Chainani, Ashish; Senba, Yasunori; Ohashi, Haruhiko; Ohta, Hiromichi; Shin, Shik

2008-02-01

452

Exciton-like electromagnetic excitations in non-ideal microcavity supercrystals  

PubMed Central

We study localized photonic excitations in a quasi-two-dimensional non-ideal binary microcavity lattice with use of the virtual crystal approximation. The effect of point defects (vacancies) on the excitation spectrum is investigated by numerical modelling. We obtain the dispersion and the energy gap of the electromagnetic excitations which may be considered as Frenkel exciton-like quasiparticles and analyze the dependence of their density of states on the defect concentrations in a microcavity supercrystal. PMID:25374150

Rumyantsev, Vladimir; Fedorov, Stanislav; Gumennyk, Kostyantyn; Sychanova, Marina; Kavokin, Alexey

2014-01-01

453

Exciton-like electromagnetic excitations in non-ideal microcavity supercrystals.  

PubMed

We study localized photonic excitations in a quasi-two-dimensional non-ideal binary microcavity lattice with use of the virtual crystal approximation. The effect of point defects (vacancies) on the excitation spectrum is investigated by numerical modelling. We obtain the dispersion and the energy gap of the electromagnetic excitations which may be considered as Frenkel exciton-like quasiparticles and analyze the dependence of their density of states on the defect concentrations in a microcavity supercrystal. PMID:25374150

Rumyantsev, Vladimir; Fedorov, Stanislav; Gumennyk, Kostyantyn; Sychanova, Marina; Kavokin, Alexey

2014-01-01

454

Implant Experience and Positional Stability of AC Electromagnetic Beacon Transponders Used to Localize Patients for External Beam Radiation Therapy of the Prostate  

E-print Network

Implant Experience and Positional Stability of AC Electromagnetic Beacon® Transponders Used to Localize Patients for External Beam Radiation Therapy of the Prostate T.R. Willoughby1, P.A. Kupelian1, J.W. Hadley5, J.T. Wei6, H.M. Sandler5 1 Radiation Oncology, MD Anderson Cancer Center Orlando, Orlando, FL, 2

Pouliot, Jean

455

High-energy spin and charge excitations in electron-doped copper oxide superconductors.  

PubMed

The evolution of electronic (spin and charge) excitations upon carrier doping is an extremely important issue in superconducting layered cuprates and the knowledge of its asymmetry between electron- and hole-dopings is still fragmentary. Here we combine X-ray and neutron inelastic scattering measurements to track the doping dependence of both spin and charge excitations in electron-doped materials. Copper L3 resonant inelastic X-ray scattering spectra show that magnetic excitations shift to higher energy upon doping. Their dispersion becomes steeper near the magnetic zone centre and they deeply mix with charge excitations, indicating that electrons acquire a highly itinerant character in the doped metallic state. Moreover, above the magnetic excitations, an additional dispersing feature is observed near the ?-point, and we ascribe it to particle-hole charge excitations. These properties are in stark contrast with the more localized spin excitations (paramagnons) recently observed in hole-doped compounds even at high doping levels. PMID:24762677

Ishii, K; Fujita, M; Sasaki, T; Minola, M; Dellea, G; Mazzoli, C; Kummer, K; Ghiringhelli, G; Braicovich, L; Tohyama, T; Tsutsumi, K; Sato, K; Kajimoto, R; Ikeuchi, K; Yamada, K; Yoshida, M; Kurooka, M; Mizuki, J

2014-01-01

456

Effect of burst ions on the excitation of ion-acoustic solitons in a drifting plasma  

Microsoft Academic Search

The characteristics of fast burst ions and ion-acoustic solitons in a drifting plasma, as well as their interaction, are investigated experimentally. It is shown that the soliton evolves from the normal fast ion-beam mode excited locally in the presheath region of an excitation grid. The burst ions are created by applying a positive ramp voltage to the grid. Adjusting the

De-Long Xiao; J. X. Ma; Yi-Ren Li; Yang-Fang Li; M. Y. Yu

2007-01-01

457

Exploring the eddy current excitation invariance to infer about defect characteristics  

SciTech Connect

This paper explores the excitation probe excitation field invariance when the eddy current method is applied to detect, localize and characterize material defects in conductive nonmagnetic media. The cases relative to rotational symmetry in circular solenoidal probes and translation symmetry in constant field probes are presented. The experimental data shows that this theoretical treatment is useful to preview the behavior of these probes.

Ribeiro, A. Lopes; Ramos, H. G. [I and M Group, Instituto de Telecomunicacoes, Lisboa, Portugal Instituto Superior Tecnico, DEEC, Lisboa (Portugal)

2011-06-23

458

The Excitation of the Far Ultraviolet Electroglow Emissions on Uranus, Saturn, and Jupiter  

Microsoft Academic Search

We propose that the diffuse FUV emissions of H and H 2 in excess of photoelectron excitation observed from the sunlit atmospheres of Uranus, Saturn, and Jupiter are produced by electric field acceleration of photoelectrons and ions locally in the upper atmospheres. This in situ acceleration is required to satisfy the many observational constraints on the altitude distribution, exciting particle

John T. Clarke; Mary K. Hudson; Yuk L. Yung

1987-01-01

459

An overview of the comprehensive proton therapy machine quality assurance procedures implemented at The University of Texas M. D. Anderson Cancer Center Proton Therapy Center-Houston  

SciTech Connect

The number of proton and carbon ion therapy centers is increasing; however, since the publication of the International Commission on Radiation Units and Measurements report, there has been no dedicated report dealing with proton therapy quality assurance. The purpose of this article is to describe the quality assurance procedures performed on the passively scattered proton therapy beams at The University of Texas M. D. Anderson Cancer Center Proton Therapy Center in Houston. The majorities of these procedures are either adopted from procedures outlined in the American Association of Physicists in Medical Task Group (TG) 40 report or are a modified version of the TG 40 procedures. In addition, new procedures, which were designed specifically to be applicable to the synchrotron at the author's center, have been implemented. The authors' procedures were developed and customized to ensure patient safety and accurate operation of synchrotron to within explicit limits. This article describes these procedures and can be used by others as a guideline for developing QA procedures based on particle accelerator specific parameters and local regulations pertinent to any new facility.

Arjomandy, Bijan; Sahoo, Narayan; Zhu, X. Ronald; Zullo, John R.; Wu, Richard Y.; Zhu Mingping; Ding Xiaoning; Martin, Craig; Ciangaru, George; Gillin, Michael T. [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1840 Old Spanish Trail, Houston, Texas 77025 (United States)

2009-06-15

460

Radioactivity Induced by Nuclear Excitation I. Excitation by Neutrons  

Microsoft Academic Search

It is shown that the 4.1-hr. period of indium can be produced by nuclear excitation of indium and is to be attributed to an excited metastable state, In115,* of the stable In115. This result is obtained by studying the radioactivity produced in indium by neutrons of different energy distributions and by studying the chain reactions produced in cadmium by fast

M. Goldhaber; R. D. Hill; Leo Szilard

1939-01-01

461

Importance of considering helium excited states in He+ scattering by an aluminum surface  

NASA Astrophysics Data System (ADS)

The He+/Al system is a very interesting projectile-surface combination which was thought initially as an example of a pure Auger neutralization mechanism. Then, because of the measured reionization explained by the antibonding interaction of the projectile state with the core target states, the resonant charge exchange with the band states was considered as another important contribution to the neutralization. Nevertheless, by only considering the neutralization to the ground state of helium, the measured ion survival probability is still overestimated. On the other hand, measurements of electron emission from an Al surface bombarded by He positive ions suggested the possibility of occupied excited states of helium due to the ion-surface collision. In this work, we also include the excited states of He within the time-dependent scattering process in which both neutralization mechanisms, resonant and Auger, are simultaneously contemplated. Our starting point is a multiorbital Anderson Hamiltonian projected over the selected space of ground and excited atomic configurations. An extra term related to the Auger mechanism is added to this Hamiltonian. A difference with previous works is that this approach includes the electron spin and, therefore, the spin fluctuation statistics in the charge-exchange process is correctly taken into account. We find a notable improvement in the agreement with the experiments and also that the interference between both mechanisms is not dramatic.

Iglesias-García, A.; García, Evelina A.; Goldberg, E. C.

2014-11-01

462

Manipulation of near field polarization by far field excitation  

NASA Astrophysics Data System (ADS)

Metal nanoparticle assemblies of designed structure are investigated as substrates for polarization manipulation in the near field region. Gold nanoparticles are known for their optical response due to the excitation of surface plasmons. Surface plasmons in coupled particles can strongly modulate light either in the far or near field region. The most common near field application of coupled particles is as field enhancing substrates for amplifying signals of molecules, for example, Raman signals, IR signals or fluorescence signals. However, the capabilities of metal nanoparticle assemblies can be extended beyond field amplification. Groups of particles can function as small antennas which convert far field excitation into localized fields with specific polarization. Through simulations we demonstrate that the near field polarization can be partially controlled through suitable design of nanoparticle configuration. The benefit of this configuration is that no probe excitation or other localized excitation is needed. The far field signal is converted into specific spots with designed polarization, which is not necessarily the same as excitation. Polarization is manipulated through the coupling of different surface plasmon modes. This polarization modulation extends down to the few nanometer scale and may provide us more control of interaction of light with nano-scale emitters or molecules.

Chen, Shiuan-Yeh; Lazarides, Anne A.

2010-02-01

463

Local Wegner and Lifshitz tails estimates for the density of states for continuous random Schrödinger operators  

NASA Astrophysics Data System (ADS)

We introduce and prove local Wegner estimates for continuous generalized Anderson Hamiltonians, where the single-site random variables are independent but not necessarily identically distributed. In particular, we get Wegner estimates with a constant that goes to zero as we approach the bottom of the spectrum. As an application, we show that the (differentiated) density of states exhibits the same Lifshitz tails upper bound as the integrated density of states.

Combes, Jean-Michel; Germinet, François; Klein, Abel

2014-08-01

464

Michael T. Martin, "Madeline Anderson in Conversation: Pioneering an African American Documentary Tradition." Black Camera, An International Film Journal, Vol. 5  

E-print Network

Tradition." Black Camera, An International Film Journal, Vol. 5 No. 1 (Fall 2013), 72­93. Madeline Anderson is lightened #12;74 BLACK CAMERA 5:1 empowerment. And it is here that her contribution to a profoundly human

Indiana University

465

Rerouting excitation transfers in the Fenna-Matthews-Olson complex.  

PubMed

We investigate, using the hierarchy method, the entanglement and the excitation transfer efficiency of the Fenna-Matthews-Olson (FMO) complex under two different local modifications: the suppression of transitions between particular sites and localized changes to the protein environment. We find that inhibiting the connection between site 5 and site 6, or completely disconnecting site 5 from the complex, leads to a dramatic enhancement of the entanglement between site 6 and site 7. Similarly, the transfer efficiency actually increases if site 5 is entirely disconnected from the complex. We further show that if sites 5 and 7 are conjointly removed, the efficiency falls. This suggests that while not contributing to the transport efficiency in a normal complex, site 5 may introduce a redundant transport route in case of damage to site 7. Our results suggest an overall robustness of the excitation-energy transfer in the FMO complex under mutations, local defects, and other abnormal situations. PMID:24125226

Chen, Guang-Yin; Lambert, Neill; Li, Che-Ming; Chen, Yueh-Nan; Nori, Franco

2013-09-01

466

Industrial applications of photonuclear resonance excitation  

E-print Network

Photonuclear resonance excitation refers to a variety of photonuclear interaction processes that lead to the excitation of a nucleus from some initial state to a higher energy nuclear state. Typical excited nuclear state ...

Chichester, David Lee, 1971-

2000-01-01

467

Exciting Students About Science & Engineering ...  

E-print Network

applications include nanomachines, bioimplants, smart materials, fuel cells, genetic engineering and spaceExciting Students About Science & Engineering ... ASM MATERIALS CAMP® 2013 MATERIALS IN TODAY'S WORLD Materials science and engineering is a study of the relationship between the structure

Evans, Paul G.

468

Parametric Excitation of a DWSC  

E-print Network

methods of analysis and the effect of damping (especially viscous drag) on parametric excitation and instability. The thesis uses Mathieu's equation as the basis for stability analysis and time-simulates the coupled heave-sway-roll EOM. Time...

Lakhotia, Chandan

2011-08-08

469

Laser-induced nuclear excitation  

SciTech Connect

An analysis is presented of the Coulomb excitation of low-lying nuclear levels by the electrons produced by strong-field ionization of atoms. It is shown that the resulting short-lived radioactivity can be as high as on the order of 10{sup 3} Ci for certain isotopes excited by using modern laser systems. Relativistic effects are demonstrated that substantially increase radioactivity as compared to that predicted by nonrelativistic theory results.

Zon, B. A., E-mail: zon@niif.vsu.ru; Kornev, A. S., E-mail: a-kornev@yandex.r [Voronezh State University (Russian Federation)

2010-05-15

470

Thermoelectric transport properties through a single-walled zig-zag carbon nanotube side coupled to a correlated quantum dot: Atomic approach for the finite U-impurity Anderson model  

NASA Astrophysics Data System (ADS)

We study the thermopower S, linear thermal conductance ?, linear electric conductance G and thermoelectric figure of merit Z properties of a single-walled zig-zag carbon nanotube side coupled to a correlated quantum dot (QD). We employ the recently developed U-finite atomic approach for the Single Impurity Anderson model (SIAM). The quantum dot is linked to the localized states in the model, considering a finite Coulombic repulsion U, and the conduction band in the model is associated with the single walled zig-zag metallic carbon nanotube (n=3), and is described by a tight-binding approximation in order to obtain Green's function of the nanotube. The thermoelectric transport coefficients were obtained using the Keldysh non-equilibrium Green's function technique with the Onsager relation in the linear regime automatically satisfied. Results indicate that this system can be employed in possible thermoelectric device applications at low temperatures when strong charge fluctuations are present in the QD.

Ramos, Edwin; Franco, Roberto; Silva-Valencia, Jereson; Figueira, Marcos Sergio

2014-12-01

471

Phase relaxation in slowly changing environments: Evaluation of the Kubo-Anderson model for a continuous-time random walk  

NASA Astrophysics Data System (ADS)

The Kubo-Anderson model is a stochastic model of phase relaxation of an ensemble of systems in a fluctuating environment. This model is usually studied under the assumption that the system-environment interaction is a Gaussian stochastic process. This assumption only holds if the environment changes a very large number of times on the time scale of the system's motion. This paper reviews our work on the Kubo-Anderson model for the case where this interaction is a continuous-time random walk. A continuous-time random walk is a simple model for a `slowly changing environment', i.e., one which makes a relatively small number of changes on the time scale of the system's motion. We present the key results from this model and show how to apply them to common problems in magnetic resonance spectroscopy and and non-linear optical spectroscopy.

Packwood, Daniel M.

2013-02-01

472

Matter-wave localization in a random potential  

SciTech Connect

By numerical and variational solutions of the Gross-Pitaevskii equation, we studied the localization of a noninteracting and weakly interacting Bose-Einstein condensate (BEC) in a disordered cold atom lattice and a speckle potential. In the case of a single BEC fragment, the variational analysis produced good results. For a weakly disordered potential, the localized BEC's are found to have an exponential tail as in the weak Anderson localization. We also investigated the expansion of a noninteracting BEC in these potentials. We find that the BEC will be locked in an appropriate localized state after an initial expansion and will execute breathing oscillation around a mean shape when a BEC at equilibrium in a harmonic trap is suddenly released into a disorder potential.

Cheng Yongshan [Instituto de Fisica Teorica, UNESP - Universidade Estadual Paulista, 01.140-070 Sao Paulo, Sao Paulo (Brazil); Department of Physics, Hubei Normal University, Huangshi 435002 (China); Adhikari, S. K. [Instituto de Fisica Teorica, UNESP - Universidade Estadual Paulista, 01.140-070 Sao Paulo, Sao Paulo (Brazil)

2010-07-15

473

Redox Control of Cardiac Excitability  

PubMed Central

Abstract Reactive oxygen species (ROS) have been associated with various human diseases, and considerable attention has been paid to investigate their physiological effects. Various ROS are synthesized in the mitochondria and accumulate in the cytoplasm if the cellular antioxidant defense mechanism fails. The critical balance of this ROS synthesis and antioxidant defense systems is termed the redox system of the cell. Various cardiovascular diseases have also been affected by redox to different degrees. ROS have been indicated as both detrimental and protective, via different cellular pathways, for cardiac myocyte functions, electrophysiology, and pharmacology. Mostly, the ROS functions depend on the type and amount of ROS synthesized. While the literature clearly indicates ROS effects on cardiac contractility, their effects on cardiac excitability are relatively under appreciated. Cardiac excitability depends on the functions of various cardiac sarcolemal or mitochondrial ion channels carrying various depolarizing or repolarizing currents that also maintain cellular ionic homeostasis. ROS alter the functions of these ion channels to various degrees to determine excitability by affecting the cellular resting potential and the morphology of the cardiac action potential. Thus, redox balance regulates cardiac excitability, and under pathological regulation, may alter action potential propagation to cause arrhythmia. Understanding how redox affects cellular excitability may lead to potential prophylaxis or treatment for various arrhythmias. This review will focus on the studies of redox and cardiac excitation. Antioxid. Redox Signal. 18, 432–468. PMID:22897788

Aggarwal, Nitin T.

2013-01-01

474

Electron-excited molecule interactions  

SciTech Connect

In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10{sup 6} to 10{sup 7} times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs.

Christophorou, L.G. (Oak Ridge National Lab., TN (USA) Tennessee Univ., Knoxville, TN (USA). Dept. of Physics)

1991-01-01

475

Electrostatic Tuning of Cellular Excitability  

PubMed Central

Abstract Voltage-gated ion channels regulate the electric activity of excitable tissues, such as the heart and brain. Therefore, treatment for conditions of disturbed excitability is often based on drugs that target ion channels. In this study of a voltage-gated K channel, we propose what we believe to be a novel pharmacological mechanism for how to regulate channel activity. Charged lipophilic substances can tune channel opening, and consequently excitability, by an electrostatic interaction with the channel's voltage sensors. The direction of the effect depends on the charge of the substance. This was shown by three compounds sharing an arachidonyl backbone but bearing different charge: arachidonic acid, methyl arachidonate, and arachidonyl amine. Computer simulations of membrane excitability showed that small changes in the voltage dependence of Na and K channels have prominent impact on excitability and the tendency for repetitive firing. For instance, a shift in the voltage dependence of a K channel with ?5 or +5 mV corresponds to a threefold increase or decrease in K channel density, respectively. We suggest that electrostatic tuning of ion channel activity constitutes a novel and powerful pharmacological approach with which to affect cellular excitability. PMID:20141752

Börjesson, Sara I.; Parkkari, Teija; Hammarström, Sven; Elinder, Fredrik

2010-01-01

476

Excitation of spin waves by an electric current  

NASA Astrophysics Data System (ADS)

The excitation of spin waves in an unbounded ferromagnetic film by a direct spin-polarized current distributed over a small area is treated macroscopically. The derived critical threshold current for excitation has two additive terms: The first arises from radiation of spin waves and is constant. The second arises from local viscous dissipation and varies in proportion to damping coefficient, external field, and area. An application of these predictions modifies the existing interpretation of experiments by Tsoi and collaborators employing currents flowing through point contacts.

Slonczewski, J. C.

1999-05-01

477

Excitable media in open and closed chaotic flows  

E-print Network

We investigate the response of an excitable medium to a localized perturbation in the presence of a two-dimensional smooth chaotic flow. Two distinct types of flows are numerically considered: open and closed. For both of them three distinct regimes are found, depending on the relative strengths of the stirring and the rate of the excitable reaction. In order to clarify and understand the role of the many competing mechanisms present, simplified models of the process are introduced. They are one-dimensional baker-map models for the flow and a one-dimensional approximation for the transverse profile of the filaments.

Zoltan Neufeld; Cristobal Lopez; Emilio Hernandez-Garcia; Oreste Piro

2002-09-11

478

Identification of Mott insulators and Anderson insulators in self-assembled gold nanoparticles thin films  

NASA Astrophysics Data System (ADS)

How the interparticle tunnelling affects the charge conduction of self-assembled gold nanoparticles is studied by three means: tuning the tunnel barrier width by different molecule modification and by substrate bending, and tuning the barrier height by high-dose electron beam exposure. All approaches indicate that the metal-Mott insulator transition is governed predominantly by the interparticle coupling strength, which can be quantified by the room temperature sheet resistance. The Hubbard gap, following the prediction of quantum fluctuation theory, reduces to zero rapidly as the sheet resistance decreases to the quantum resistance. At very low temperature, the fate of devices near the Mott transition depends on the strength of disorder. The charge conduction is from nearest-neighbour hopping to co-tunnelling between nanoparticles in Mott insulators whereas it is from variable-range hopping through charge puddles in Anderson insulators. When the two-dimensional nanoparticle network is under a unidirectional strain, the interparticle coupling becomes anisotropic so the average sheet resistance is required to describe the charge conduction.How the interparticle tunnelling affects the charge conduction of self-assembled gold nanoparticles is studied by three means: tuning the tunnel barrier width by different molecule modification and by substrate bending, and tuning the barrier height by high-dose electron beam exposure. All approaches indicate that the metal-Mott insulator transition is governed predominantly by the interparticle coupling strength, which can be quantified by the room temperature sheet resistance. The Hubbard gap, following the prediction of quantum fluctuation theory, reduces to zero rapidly as the sheet resistance decreases to the quantum resistance. At very low temperature, the fate of devices near the Mott transition depends on the strength of disorder. The charge conduction is from nearest-neighbour hopping to co-tunnelling between nanoparticles in Mott insulators whereas it is from variable-range hopping through charge puddles in Anderson insulators. When the two-dimensional nanoparticle network is under a unidirectional strain, the interparticle coupling becomes anisotropic so the average sheet resistance is required to describe the charge conduction. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr06627d

Jiang, Cheng-Wei; Ni, I.-Chih; Tzeng, Shien-Der; Wu, Cen-Shawn; Kuo, Watson

2014-05-01

479

46 CFR 111.12-3 - Excitation.  

Code of Federal Regulations, 2013 CFR

...COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Generator Construction and Circuits § 111.12-3 Excitation. In general, excitation must meet...

2013-10-01

480

46 CFR 111.12-3 - Excitation.  

Code of Federal Regulations, 2011 CFR

...COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Generator Construction and Circuits § 111.12-3 Excitation. In general, excitation must meet...

2011-10-01

481

46 CFR 111.12-3 - Excitation.  

Code of Federal Regulations, 2012 CFR

...COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Generator Construction and Circuits § 111.12-3 Excitation. In general, excitation must meet...

2012-10-01

482

MD Anderson-led study finds metabolic protein wields phosphate group to activate cancer-promoting genes  

Cancer.gov

A metabolic protein that nourishes cancer cells also activates tumor-promoting genes by loosening part of the packaging that entwines DNA to make up chromosomes, a team led by scientists at The University of Texas MD Anderson Cancer Center reports in the Aug. 16 issue of Cell. Working in cell lines and mouse models of glioblastoma multiforme, the most lethal form of brain tumor, the team showed that pyruvate kinase M2 (PKM2) fuels tumor growth by influencing a histone protein.

483

MD Anderson study finds lung cancer patients live longer if they use beta-blockers while receiving radiotherapy  

Cancer.gov

Patients with non-small-cell lung cancer survive longer if they are taking beta-blockers while receiving radiotherapy, according to a study of 722 patients published in the cancer journal Annals of Oncology. Researchers at the University of Texas MD Anderson Cancer Center reviewed the progress and outcomes of patients who had received radiotherapy as their main or first line of treatment for cancer.

484

MD Anderson study finds weekly dose reduces a targeted drug's side effects but not its activity against acute lymphocytic leukemia  

Cancer.gov

A potent chemotherapy agent wrapped within a monoclonal antibody selectively destroys the malignant cells responsible for acute lymphocytic leukemia (ALL) in either weekly or monthly dosing, researchers report at the 54th ASH Annual Meeting and Exposition. This "Trojan horse" assault on the cancer cells has significantly increased the response rate among patients with ALL, and now an MD Anderson Cancer Center clinical trial finds that weekly dosing works well and reduces side effects.

485

MD Anderson study finds majority of older, early-stage breast cancer patients benefit from radiation after lumpectomy  

Cancer.gov

For the majority of older, early-stage breast cancer patients, radiation therapy following breast conserving surgery may help prevent the need for a later mastectomy, according to research from The University of Texas MD Anderson Cancer Center. The findings, published in the journal Cancer, are contrary to current national treatment guidelines, which recommend that older women with early stage, estrogen-positive disease be treated with lumpectomy followed by estrogen blocker therapy alone -- and forgo radiation therapy post-surgery.

486

Two-photon excitation photodynamic therapy with Photofrin  

NASA Astrophysics Data System (ADS)

Photodynamic therapy (PDT) based on simultaneous two-photon (2-?) excitation has a potential advantage of highly targeted treatment by means of nonlinear localized photosensitizer excitation. One of the possible applications of 2-? PDT is a treatment of exodus age-related macular degeneration where highly targeted excitation of photosensitizer in neovasculature is vital for reducing collateral damage to healthy surrounding tissue. To investigate effect of 2-? PDT Photofrin was used as an archetypal photosensitizer. First, 2-? absorption properties of Photofrin in the 750 - 900 nm excitation wavelength range were investigated. It was shown that above 800 nm 2-? interaction was dominant mode of excitation. The 2-? cross section of Photofrin was rather small and varied between 5 and 10 GM (1 GM = 10-50 cm4s/photon) in this wavelength range. Next, endothelial cells treated with Photofrin were used to model initial effect of 2-? PDT on neovasculature. Ultrashort laser pulses provided by mode-locked Ti:sapphire laser (pulse duration at the sample 300 fs, repetition rate 90 MHz, mean laser power 10 mW, excitation wavelength 850 nm) were used for the excitation of the photosensitizer. Before 2-? excitation of the Photofrin cells formed a single continuous sheet at the bottom of the well. The tightly focused laser light was scanned repeatedly over the cell layer. After irradiation the cell layer of the control cells stayed intact while cells treated with photofrin became clearly disrupted. The light doses required were high (6300 Jcm(-2) for ~ 50% killing), but 2-? cytotoxicity was unequivocally demonstrated.

Karotki, Aliaksandr; Khurana, Mamta; Lepock, James R.; Wilson, Brian C.

2005-09-01

487

Quantum quenches in the many-body localized phase  

NASA Astrophysics Data System (ADS)

Many-body localized (MBL) systems are characterized by the absence of transport and thermalization and, therefore, cannot be described by conventional statistical mechanics. In this paper, using analytic arguments and numerical simulations, we study the behavior of local observables in an isolated MBL system following a quantum quench. For the case of a global quench, we find that the local observables reach stationary, highly nonthermal values at long times as a result of slow dephasing characteristic of the MBL phase. These stationary values retain the local memory of the initial state due to the existence of local integrals of motion in the MBL phase. The temporal fluctuations around stationary values exhibit universal power-law decay in time, with an exponent set by the localization length and the diagonal entropy of the initial state. Such a power-law decay holds for any local observable and is related to the logarithmic in time growth of entanglement in the MBL phase. This behavior distinguishes the MBL phase from both the Anderson insulator (where no stationary state is reached) and from the ergodic phase (where relaxation is expected to be exponential). For the case of a local quench, we also find a power-law approach of local observables to their stationary values when the system is prepared in a mixed state. Quench protocols considered in this paper can be naturally implemented in systems of ultracold atoms in disordered optical lattices, and the behavior of local observables provides a direct experimental signature of many-body localization.

Serbyn, Maksym; Papi?, Z.; Abanin, D. A.

2014-11-01

488

Colloidal quantum dots as probes of excitation field enhancement in photonic antennas.  

PubMed

Optical antennas are essential devices to interface light to nanoscale volumes and locally enhance the electromagnetic intensity. Various experimental methods can be used to quantify the antenna amplification on the emission process, yet characterizing the antenna amplification at the excitation frequency solely is a challenging task. Such experimental characterization is highly needed to fully understand and optimize the antenna response. Here, we describe a novel experimental tool to directly measure the antenna amplification on the excitation field independently of the emission process. We monitor the transient emission dynamics of colloidal quantum dots and show that the ratio of doubly to singly excited state photoluminescence decay amplitudes is an accurate tool to quantify the local excitation intensity amplification. This effect is demonstrated on optical antennas made of polystyrene microspheres and gold nanoapertures, and supported by numerical computations. The increased doubly excited state formation on nanoantennas realizes a new demonstration of enhanced light-matter interaction at the nanoscale. PMID:20731440

Aouani, Heykel; Itzhakov, Stella; Gachet, David; Devaux, Eloïse; Ebbesen, Thomas W; Rigneault, Hervé; Oron, Dan; Wenger, Jérôme

2010-08-24

489

An inventory of wetlands in the East Fork Poplar Creek floodplain, Anderson and Roane Counties, Tennessee  

SciTech Connect

An inventory of wetlands within the floodplain of East Fork Poplar Creek (EFPC) in Anderson and Roane Counties, Tennessee was conducted during October, 1991 through May, 1992 for the US Department of Energy (DOE) by the US Army Corps of Engineers, Nashville District. About 15 miles of EFPC channel and 500 acres of its floodplain are contaminated with mercury and other contaminants released from the Y-12 Plant on the DOE Oak Ridge Reservation. The wetland inventory will serve as baseline information for D