Sign realized jump risk and the cross-section of stock returns: Evidence from China's stock market

PubMed Central

Chao, Youcong; Liu, Xiaoqun; Guo, Shijun

2017-01-01

Using 5-minute high frequency data from the Chinese stock market, we employ a non-parametric method to estimate Fama-French portfolio realized jumps and investigate whether the estimated positive, negative and sign realized jumps could forecast or explain the cross-sectional stock returns. The Fama-MacBeth regression results show that not only have the realized jump components and the continuous volatility been compensated with risk premium, but also that the negative jump risk, the positive jump risk and the sign jump risk, to some extent, could explain the return of the stock portfolios. Therefore, we should pay high attention to the downside tail risk and the upside tail risk. PMID:28771514

Vanadium fine-structure K-shell electron impact ionization cross sections for fast-electron diagnostic in laser–solid experiments

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

Palmeri, P., E-mail: patrick.palmeri@umons.ac.be; Quinet, P., E-mail: pascal.quinet@umons.ac.be; IPNAS, Université de Liège, B-4000 Liège

2015-09-15

The K-shell electron impact ionization (EII) cross section, along with the K-shell fluorescence yield, is one of the key atomic parameters for fast-electron diagnostic in laser–solid experiments through the K-shell emission cross section. In addition, in a campaign dedicated to the modeling of the K lines of astrophysical interest (Palmeri et al. (2012)), the K-shell fluorescence yields for the K-vacancy fine-structure atomic levels of all the vanadium isonuclear ions have been calculated. In this study, the K-shell EII cross sections connecting the ground and the metastable levels of the parent vanadium ions to the daughter ions K-vacancy levels considered in Palmerimore » et al. (2012) have been determined. The relativistic distorted-wave (DW) approximation implemented in the FAC atomic code has been used for the incident electron kinetic energies up to 20 times the K-shell threshold energies. Moreover, the resulting DW cross sections have been extrapolated at higher energies using the asymptotic behavior of the modified relativistic binary encounter Bethe model (MRBEB) of Guerra et al. (2012) with the density-effect correction proposed by Davies et al. (2013)« less

Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural

NASA Astrophysics Data System (ADS)

Jones, D. B.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; Blanco, F.; García, G.; Brunger, M. J.

2016-04-01

We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20-250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron-furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.

Electron impact ionisation cross sections of iron oxides

NASA Astrophysics Data System (ADS)

Huber, Stefan E.; Mauracher, Andreas; Sukuba, Ivan; Urban, Jan; Maihom, Thana; Probst, Michael

2017-12-01

We report electron impact ionisation cross sections (EICSs) of iron oxide molecules, FexOx and FexOx+1 with x = 1, 2, 3, from the ionisation threshold to 10 keV, obtained with the Deutsch-Märk (DM) and binary-encounter-Bethe (BEB) methods. The maxima of the EICSs range from 3.10 to 9 . 96 × 10-16 cm2 located at 59-72 eV and 5.06 to 14.32 × 10-16 cm2 located at 85-108 eV for the DM and BEB approaches, respectively. The orbital and kinetic energies required for the BEB method are obtained by employing effective core potentials for the inner core electrons in the quantum chemical calculations. The BEB cross sections are 1.4-1.7 times larger than the DM cross sections which can be related to the decreasing population of the Fe 4s orbitals upon addition of oxygen atoms, together with the different methodological foundations of the two methods. Both the DM and BEB cross sections can be fitted excellently to a simple analytical expression used in modelling and simulation codes employed in the framework of nuclear fusion research. Supplementary material in the form of one pdf file available from the Journal web page at http://https://doi.org/10.1140/epjd/e2017-80308-2.

Electron impact ionization cross sections of beryllium-tungsten clusters*

NASA Astrophysics Data System (ADS)

Sukuba, Ivan; Kaiser, Alexander; Huber, Stefan E.; Urban, Jan; Probst, Michael

2016-01-01

We report calculated electron impact ionization cross sections (EICSs) of beryllium-tungsten clusters, BenW with n = 1,...,12, from the ionization threshold to 10 keV using the Deutsch-Märk (DM) and the binary-encounter-Bethe (BEB) formalisms. The positions of the maxima of DM and BEB cross sections are mostly close to each other. The DM cross sections are more sensitive with respect to the cluster size. For the clusters smaller than Be4W they yield smaller cross sections than BEB and vice versa larger cross sections than BEB for clusters larger than Be6W. The maximum cross section values for the singlet-spin groundstate clusters range from 7.0 × 10-16 cm2 at 28 eV (BeW) to 54.2 × 10-16 cm2 at 43 eV (Be12W) for the DM cross sections and from 13.5 × 10-16 cm2 at 43 eV (BeW) to 38.9 × 10-16 cm2 at 43 eV (Be12W) for the BEB cross sections. Differences of the EICSs in different isomers and between singlet and triplet states are also explored. Both the DM and BEB cross sections could be fitted perfectly to a simple expression used in modeling and simulation codes in the framework of nuclear fusion research. Contribution to the Topical Issue "Atomic Cluster Collisions (7th International Symposium)", edited by Gerardo Delgado Barrio, Andrey Solov'Yov, Pablo Villarreal, Rita Prosmiti.Supplementary material in the form of one pdf file available from the Journal web page at http://dx.doi.org/10.1140/epjd/e2015-60583-7

Symmetry preserving truncations of the gap and Bethe-Salpeter equations

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

Binosi, Daniele; Chang, Lei; Papavassiliou, Joannis

2016-05-01

Ward-Green-Takahashi (WGT) identities play a crucial role in hadron physics, e.g. imposing stringent relationships between the kernels of the one-and two-body problems, which must be preserved in any veracious treatment of mesons as bound states. In this connection, one may view the dressed gluon-quark vertex, Gamma(alpha)(mu), as fundamental. We use a novel representation of Gamma(alpha)(mu), in terms of the gluon-quark scattering matrix, to develop a method capable of elucidating the unique quark-antiquark Bethe-Salpeter kernel, K, that is symmetry consistent with a given quark gap equation. A strength of the scheme is its ability to expose and capitalize on graphic symmetriesmore » within the kernels. This is displayed in an analysis that reveals the origin of H-diagrams in K, which are two-particle-irreducible contributions, generated as two-loop diagrams involving the three-gluon vertex, that cannot be absorbed as a dressing of Gamma(alpha)(mu) in a Bethe-Salpeter kernel nor expressed as a member of the class of crossed-box diagrams. Thus, there are no general circumstances under which the WGT identities essential for a valid description of mesons can be preserved by a Bethe-Salpeter kernel obtained simply by dressing both gluon-quark vertices in a ladderlike truncation; and, moreover, adding any number of similarly dressed crossed-box diagrams cannot improve the situation.« less

Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural

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

Jones, D. B.; Costa, R. F. da; Departamento de Física, Universidade Federal do Espírito Santo, 29075-910, Vitória, Espírito Santo

We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20–250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arisemore » due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron–furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.« less

E00-110 experiment at Jefferson Lab Hall A: Deeply virtual Compton scattering off the proton at 6 GeV

DOE PAGES

Defurne, M.; Amaryan, M.; Aniol, K. A.; ...

2015-11-03

We present final results on the photon electroproduction (more » $$\\vec{e}p\\rightarrow ep\\gamma$$) cross section in the deeply virtual Compton scattering (DVCS) regime and the valence quark region from Jefferson Lab experiment E00-110. Results from an analysis of a subset of these data were published before, but the analysis has been improved which is described here at length, together with details on the experimental setup. Furthermore, additional data have been analyzed resulting in photon electroproduction cross sections at new kinematic settings, for a total of 588 experimental bins. Results of the $Q^2$- and $$x_B$$-dependences of both the helicity-dependent and helicity-independent cross sections are discussed. The $Q^2$-dependence illustrates the dominance of the twist-2 handbag amplitude in the kinematics of the experiment, as previously noted. Thanks to the excellent accuracy of this high luminosity experiment, it becomes clear that the unpolarized cross section shows a significant deviation from the Bethe-Heitler process in our kinematics, compatible with a large contribution from the leading twist-2 DVCS$^2$ term to the photon electroproduction cross section. The necessity to include higher-twist corrections in order to fully reproduce the shape of the data is also discussed. The DVCS cross sections in this study represent the final set of experimental results from E00-110, superseding the previous publication.« less

A Call to Action: JoBeth Allen, NCTE's 2012 Outstanding Educator in the Language Arts

ERIC Educational Resources Information Center

Tisdale, Carmen

2012-01-01

This article is a tribute to JoBeth Allen, recipient of the Elementary Section's 2012 award for Outstanding Educator in the English Language Arts. Each year, this award recognizes a distinguished educator who has made major contributions to the field of language arts in elementary education. This article was written by second-grade teacher and…

Electron collisions with phenol: Total, integral, differential, and momentum transfer cross sections and the role of multichannel coupling effects on the elastic channel

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

Costa, Romarly F. da; Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, 09210-580 Santo André, São Paulo; Oliveira, Eliane M. de

2015-03-14

We report theoretical and experimental total cross sections for electron scattering by phenol (C{sub 6}H{sub 5}OH). The experimental data were obtained with an apparatus based in Madrid and the calculated cross sections with two different methodologies, the independent atom method with screening corrected additivity rule (IAM-SCAR), and the Schwinger multichannel method with pseudopotentials (SMCPP). The SMCPP method in the N{sub open}-channel coupling scheme, at the static-exchange-plus-polarization approximation, is employed to calculate the scattering amplitudes at impact energies ranging from 5.0 eV to 50 eV. We discuss the multichannel coupling effects in the calculated cross sections, in particular how the numbermore » of excited states included in the open-channel space impacts upon the convergence of the elastic cross sections at higher collision energies. The IAM-SCAR approach was also used to obtain the elastic differential cross sections (DCSs) and for correcting the experimental total cross sections for the so-called forward angle scattering effect. We found a very good agreement between our SMCPP theoretical differential, integral, and momentum transfer cross sections and experimental data for benzene (a molecule differing from phenol by replacing a hydrogen atom in benzene with a hydroxyl group). Although some discrepancies were found for lower energies, the agreement between the SMCPP data and the DCSs obtained with the IAM-SCAR method improves, as expected, as the impact energy increases. We also have a good agreement among the present SMCPP calculated total cross section (which includes elastic, 32 inelastic electronic excitation processes and ionization contributions, the latter estimated with the binary-encounter-Bethe model), the IAM-SCAR total cross section, and the experimental data when the latter is corrected for the forward angle scattering effect [Fuss et al., Phys. Rev. A 88, 042702 (2013)].« less

Price returns efficiency of the Shanghai A-Shares

NASA Astrophysics Data System (ADS)

Long, Wang Jiang; Jaaman, Saiful Hafizah; Samsudin, Humaida Banu

2014-06-01

Beta measured from the capital asset pricing model (CAPM) is the most widely used risk to estimate expected return. In this paper factors that influence Shanghai A-share stock return based on CAPM are explored and investigated. Price data of 312 companies listed on Shanghai Stock Exchange (SSE) from the year 2000 to 2011 are investigated. This study employed the Fama-MacBeth cross-sectional method to avoid weakness of traditional CAPM. In addition, this study improves the model by adjusting missing data. Findings of this study justifies that systematic risk can explain the portfolios' returns of China SSE stock market.

EXCALIBUR-at-CALIBAN: a neutron transmission experiment for {sup 238}U(n,n'{sub continuum}γ) nuclear data validation

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

Bernard, David; Leconte, Pierre; Destouches, Christophe

2015-07-01

Two recent papers justified a new experimental program to give a new basis for the validation of {sup 238}U nuclear data, namely neutron induced inelastic scattering and transport codes at neutron fission energies. The general idea is to perform a neutron transmission experiment through natural uranium material. As shown by Hans Bethe, neutron transmissions measured by dosimetric responses are linked to inelastic cross sections. This paper describes the principle and the results of such an experience called EXCALIBUR performed recently (January and October 2014) at the CALIBAN reactor facility. (authors)

Scaled plane-wave Born cross sections for atoms and molecules

NASA Astrophysics Data System (ADS)

Tanaka, H.; Brunger, M. J.; Campbell, L.; Kato, H.; Hoshino, M.; Rau, A. R. P.

2016-04-01

Integral cross sections for optically allowed electronic-state excitations of atoms and molecules by electron impact, by applying scaled plane-wave Born models, are reviewed. Over 40 years ago, Inokuti presented an influential review of charged-particle scattering, based on the theory pioneered by Bethe forty years earlier, which emphasized the importance of reliable cross-section data from low eV energies to high keV energies that are needed in many areas of radiation science with applications to astronomy, plasmas, and medicine. Yet, with a couple of possible exceptions, most computational methods in electron-atom scattering do not, in general, overlap each other's validity range in the region from threshold up to 300 eV and, in particular, in the intermediate region from 30 to 300 eV. This is even more so for electron-molecule scattering. In fact this entire energy range is of great importance and, to bridge the gap between the two regions of low and high energy, scaled plane-wave Born models were developed to provide reliable, comprehensive, and absolute integral cross sections, first for ionization by Kim and Rudd and then extended to optically allowed electronic-state excitation by Kim. These and other scaling models in a broad, general application to electron scattering from atoms and molecules, their theoretical basis, and their results for cross sections along with comparison to experimental measurements are reviewed. Where possible, these data are also compared to results from other computational approaches.

Absolute electron-impact total ionization cross sections of chlorofluoromethanes

NASA Astrophysics Data System (ADS)

Martínez, Roberto; Sierra, Borja; Redondo, Carolina; Rayo, María N. Sánchez; Castaño, Fernando

2004-12-01

An experimental study is reported on the electron-impact total ionization cross sections (TICSs) of CCl4, CCl3F, CCl2F2, and CClF3 molecules. The kinetic energy of the colliding electrons was in the 10-85 eV range. TICSs were obtained as the sum of the partial ionization cross sections of all fragment ions, measured and identified in a linear double focusing time-of-flight mass spectrometer. The resulting TICS profiles—as a function of the electron-impact energy—have been compared both with those computed by ab initio and (semi)empirical methods and with the available experimental data. The computational methods used include the binary-encounter-Bethe (BEB) modified to include atoms with principal quantum numbers n⩾3, the Deutsch and Märk (DM) formalism, and the modified additivity rule (MAR). It is concluded that both modified BEB and DM methods fit the experimental TICS for (CF4), CClF3, CCl2F2, CCl3F, and CCl4 to a high accuracy, in contrast with the poor accord of the MAR method. A discussion on the factors influencing the discrepancies of the fittings is presented.

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

Biselli, Angela S.

The generalized parton distributions (GPDs) have emerged as a universal tool to describe hadrons in terms of their elementary constituents, the quarks and the gluons. Deeply virtual Compton scattering (DVCS) on a proton or neutron (more » $N$), $$e N \\rightarrow e' N' \\gamma$$, is the process more directly interpretable in terms of GPDs. The amplitudes of DVCS and Bethe-Heitler, the process where a photon is emitted by either the incident or scattered electron, can be accessed via cross-section measurements or exploiting their interference which gives rise to spin asymmetries. Spin asymmetries, cross sections and cross-section differences can be connected to different combinations of the four leading-twist GPDs ($${H}$$, $${E}$$, $${\\tilde{H}}$$, $${\\tilde{E}}$$) for each quark flavors, depending on the observable and on the type of target. This paper gives an overview of recent experimental results obtained for DVCS at Jefferson Laboratory in the halls A and B. Several experiments have been done extracting DVCS observables over large kinematics regions. Multiple measurements with overlapping kinematic regions allow to perform a quasi-model independent extraction of the Compton form factors, which are GPDs integrals, revealing a 3D image of the nucleon.« less

HZETRN: Description of a free-space ion and nucleon transport and shielding computer program

NASA Technical Reports Server (NTRS)

Wilson, John W.; Badavi, Francis F.; Cucinotta, Francis A.; Shinn, Judy L.; Badhwar, Gautam D.; Silberberg, R.; Tsao, C. H.; Townsend, Lawrence W.; Tripathi, Ram K.

1995-01-01

The high-charge-and energy (HZE) transport computer program HZETRN is developed to address the problems of free-space radiation transport and shielding. The HZETRN program is intended specifically for the design engineer who is interested in obtaining fast and accurate dosimetric information for the design and construction of space modules and devices. The program is based on a one-dimensional space-marching formulation of the Boltzmann transport equation with a straight-ahead approximation. The effect of the long-range Coulomb force and electron interaction is treated as a continuous slowing-down process. Atomic (electronic) stopping power coefficients with energies above a few A MeV are calculated by using Bethe's theory including Bragg's rule, Ziegler's shell corrections, and effective charge. Nuclear absorption cross sections are obtained from fits to quantum calculations and total cross sections are obtained with a Ramsauer formalism. Nuclear fragmentation cross sections are calculated with a semiempirical abrasion-ablation fragmentation model. The relation of the final computer code to the Boltzmann equation is discussed in the context of simplifying assumptions. A detailed description of the flow of the computer code, input requirements, sample output, and compatibility requirements for non-VAX platforms are provided.

Cross sections for electron collision with difluoroacetylene

NASA Astrophysics Data System (ADS)

Gupta, Dhanoj; Choi, Heechol; Kwon, Deuk-Chul; Yoon, Jung-Sik; Antony, Bobby; Song, Mi-Young

2017-04-01

We report a detailed calculation of total elastic, differential elastic, momentum transfer and electronic excitation for electron impact on difluoroacetylene (C2F2) molecules using the R-matrix method at low energies. After testing many target models, the final results are reported for the target model that gave the best target properties and predicted the lowest value of the shape resonance. The shape resonance is detected at 5.86 eV and 6.49 eV with the close-coupling and static exchange models due to 2Πg (2B2g, 2B3g) states. We observed that the effect of polarization becomes prominent at low energies below 4 eV, decreasing the magnitude of the elastic cross section systematically as it increases for C2F2. We have also computed elastic cross sections for C2H2, C2F4 and C2H4 with a similar model and compared with the experimental data for these molecules along with C2F2. General agreement is found in terms of the shape and nature of the cross section. Such a comparison shows the reliability of the present method for obtaining the cross section for C2F2. The calculation of elastic scattering cross section is extended to higher energies up to 5 keV using the spherical complex optical potential method. The two methods are found to be consistent, merging at around 12 eV for the elastic scattering cross section. Finally we report the total ionization cross section using the binary encounter Bethe method for C2F2. The perfluorination effect in the shape and magnitude of the elastic, momentum transfer and ionization cross sections when compared with C2H2 showed a similar trend to that in the C2H4-C2F4 and C6H6-C6F6 systems. The cross-section data reported in this article could be an important input for the development of a C2F2 plasma model for selective etching of Si/SiO2 in the semiconductor industry.

The Bethe ansatz

NASA Astrophysics Data System (ADS)

Levkovich-Maslyuk, Fedor

2016-08-01

We give a pedagogical introduction to the Bethe ansatz techniques in integrable QFTs and spin chains. We first discuss and motivate the general framework of asymptotic Bethe ansatz for the spectrum of integrable QFTs in large volume, based on the exact S-matrix. Then we illustrate this method in several concrete theories. The first case we study is the SU(2) chiral Gross-Neveu model. We derive the Bethe equations via algebraic Bethe ansatz, solving in the process the Heisenberg XXX spin chain. We discuss this famous spin chain model in some detail, covering in particular the coordinate Bethe ansatz, some properties of Bethe states, and the classical scaling limit leading to finite-gap equations. Then we proceed to the more involved SU(3) chiral Gross-Neveu model and derive the Bethe equations using nested algebraic Bethe ansatz to solve the arising SU(3) spin chain. Finally we show how a method similar to the Bethe ansatz works in a completely different setting, namely for the 1D oscillator in quantum mechanics.

Double-differential cross section for ionization of H2O molecules by 4-MeV/u C6 + and Si13 + ions

NASA Astrophysics Data System (ADS)

Bhattacharjee, Shamik; Biswas, S.; Monti, J. M.; Rivarola, R. D.; Tribedi, L. C.

2017-11-01

Double-differential cross section (DDCS) for electrons ejected in collisions of fast C6 + and Si13 + projectiles, with a H2O vapor target, were measured. The electrons were detected over an energy range of 1-600 eV and an angular range of 20∘-160∘. The obtained DDCS spectra, for both the ions, were compared with the CDW-EIS model. Occasional reference has been made to the DDCS data for the case of 3.75-MeV/u O8 + colliding on the same molecule for an overall comparison. A reasonable agreement with theoretical results was seen for the case of C6 + and O8 + projectiles. However, between C6 + and O8 + projectiles, the deviation from theory is larger for the case of the carbon projectile. Substantial deviation starts to show up for the case of the Si13 + projectile. By numerical integration of the DDCS data, the single-differential cross section (SDCS) and total cross section (TCS) were obtained and compared with theoretical models. The present TCS data along with the other available data for p , He , and C ions were plotted together. A clear and gradual deviation from the Bethe-Born predicted q2 scaling was observed, where q is the projectile charge state. From all the data we find TCS varies as qn where n = 1.7 ± 0.1. The provided data set will be valuable in order to help model the radiation damage in hadron therapy, particularly in the Bragg peak region.

Chiral dynamics of the p wave in K-p and coupled states

NASA Astrophysics Data System (ADS)

Jido, D.; Oset, E.; Ramos, A.

2002-11-01

We perform an evaluation of the p-wave amplitudes of meson-baryon scattering in the strangeness S=-1 sector starting from the lowest order chiral Lagrangians and introducing explicitly the Σ* field with couplings to the meson-baryon states obtained using SU(6) symmetry. The N/D method of unitarization is used, equivalent, in practice, to the use of the Bethe-Salpeter equation with a cutoff. The procedure leaves no freedom for the p-waves once the s-waves are fixed and thus one obtains genuine predictions for the p-wave scattering amplitudes, which are in good agreement with experimental results for differential cross sections, as well as for the width and partial decay widths of the Σ*(1385).

Retrieve the Bethe states of quantum integrable models solved via the off-diagonal Bethe Ansatz

NASA Astrophysics Data System (ADS)

Zhang, Xin; Li, Yuan-Yuan; Cao, Junpeng; Yang, Wen-Li; Shi, Kangjie; Wang, Yupeng

2015-05-01

Based on the inhomogeneous T-Q relation constructed via the off-diagonal Bethe Ansatz, a systematic method for retrieving the Bethe-type eigenstates of integrable models without obvious reference state is developed by employing certain orthogonal basis of the Hilbert space. With the XXZ spin torus model and the open XXX spin- \\frac{1}{2} chain as examples, we show that for a given inhomogeneous T-Q relation and the associated Bethe Ansatz equations, the constructed Bethe-type eigenstate has a well-defined homogeneous limit.

Scalar products of Bethe vectors in models with {\\mathfrak{gl}}(2| 1) symmetry 1. Super-analog of Reshetikhin formula

NASA Astrophysics Data System (ADS)

Hutsalyuk, A.; Liashyk, A.; Pakuliak, S. Z.; Ragoucy, E.; Slavnov, N. A.

2016-11-01

We study the scalar products of Bethe vectors in integrable models solvable by the nested algebraic Bethe ansatz and possessing {gl}(2| 1) symmetry. Using explicit formulas of the monodromy matrix entries’ multiple actions onto Bethe vectors we obtain a representation for the scalar product in the most general case. This explicit representation appears to be a sum over partitions of the Bethe parameters. It can be used for the analysis of scalar products involving on-shell Bethe vectors. As a by-product, we obtain a determinant representation for the scalar products of generic Bethe vectors in integrable models with {gl}(1| 1) symmetry. Dedicated to the memory of Petr Petrovich Kulish.

Track structure simulations at relativistic energies: an update on cross section calculations

NASA Astrophysics Data System (ADS)

Dingfelder, Michael

Charged particle track structure simulations follow the primary, as well as all (produced) sec-ondary particles in an event-by-event matter, from starting or ejection energies down to total stopping. They provide detailed information on the spacial distributions of energy depositions, interaction types, and radical species produced. These quantities provide a starting point to describe the interaction of the radiation with matter of biological interest and to explore and estimate the effects of radiation quality on various biological responses of these systems. Of special interest is liquid water which serves as surrogate for soft tissue. Ionization and excitation cross sections for bare charged particles can be calculated within the framework of the (relativistic) plane-wave Born approximation or the (relativistic) Bethe approximation. Both theories rely on a realistic model of the dielectric response function of the material under consideration and need to address relativistic medium polarization effects like the Fermi-density effect in a consistent way. In this talk we will review and present new and updated aspects of charged particle cross section calculations for relativistic heavy ions with liquid water and other materials of biological interest. This includes an updated model for the dielectric response function of liquid water to better reflect new data from inelastic X-ray scattering (IXS) experiments using synchrotron radiation and a model for the dielectric response function of calcium, which serves as a bone surrogate. We will also discuss the implementation of relativistic effect, especially of the Fermi-density effect into the cross section calculations. This work is supported by the National Aeronautics and Space Administration (NASA), grant no. NNJ04HF39G.

Algebraic Bethe ansatz for the XXX chain with triangular boundaries and Gaudin model

NASA Astrophysics Data System (ADS)

Cirilo António, N.; Manojlović, N.; Salom, I.

2014-12-01

We implement fully the algebraic Bethe ansatz for the XXX Heisenberg spin chain in the case when both boundary matrices can be brought to the upper-triangular form. We define the Bethe vectors which yield the strikingly simple expression for the off shell action of the transfer matrix, deriving the spectrum and the relevant Bethe equations. We explore further these results by obtaining the off shell action of the generating function of the Gaudin Hamiltonians on the corresponding Bethe vectors through the so-called quasi-classical limit. Moreover, this action is as simple as it could possibly be, yielding the spectrum and the Bethe equations of the Gaudin model.

Hans Bethe, Powering the Stars, and Nuclear Physics

Science.gov Websites

dropdown arrow Site Map A-Z Index Menu Synopsis Hans Bethe, Energy Production in Stars, and Nuclear Physics physics, built atomic weapons, and called for a halt to their proliferation. Bethe's dual legacy is one of Laboratory] from 1943 to 1946. Prior to joining the Manhattan Project, Bethe taught physics at Cornell

Expanding the Bethe/Gauge dictionary

NASA Astrophysics Data System (ADS)

Bullimore, Mathew; Kim, Hee-Cheol; Lukowski, Tomasz

2017-11-01

We expand the Bethe/Gauge dictionary between the XXX Heisenberg spin chain and 2d N = (2, 2) supersymmetric gauge theories to include aspects of the algebraic Bethe ansatz. We construct the wave functions of off-shell Bethe states as orbifold defects in the A-twisted supersymmetric gauge theory and study their correlation functions. We also present an alternative description of off-shell Bethe states as boundary conditions in an effective N = 4 supersymmetric quantum mechanics. Finally, we interpret spin chain R-matrices as correlation functions of Janus interfaces for mass parameters in the supersymmetric quantum mechanics.

Algebraic Bethe ansatz for the XXZ Heisenberg spin chain with triangular boundaries and the corresponding Gaudin model

NASA Astrophysics Data System (ADS)

Manojlović, N.; Salom, I.

2017-10-01

The implementation of the algebraic Bethe ansatz for the XXZ Heisenberg spin chain in the case, when both reflection matrices have the upper-triangular form is analyzed. The general form of the Bethe vectors is studied. In the particular form, Bethe vectors admit the recurrent procedure, with an appropriate modification, used previously in the case of the XXX Heisenberg chain. As expected, these Bethe vectors yield the strikingly simple expression for the off-shell action of the transfer matrix of the chain as well as the spectrum of the transfer matrix and the corresponding Bethe equations. As in the XXX case, the so-called quasi-classical limit gives the off-shell action of the generating function of the corresponding trigonometric Gaudin Hamiltonians with boundary terms.

Topics in Bethe Ansatz

NASA Astrophysics Data System (ADS)

Wang, Chunguang

Integrable quantum spin chains have close connections to integrable quantum field. theories, modern condensed matter physics, string and Yang-Mills theories. Bethe. ansatz is one of the most important approaches for solving quantum integrable spin. chains. At the heart of the algebraic structure of integrable quantum spin chains is. the quantum Yang-Baxter equation and the boundary Yang-Baxter equation. This. thesis focuses on four topics in Bethe ansatz. The Bethe equations for the isotropic periodic spin-1/2 Heisenberg chain with N. sites have solutions containing ±i/2 that are singular: both the corresponding energy and the algebraic Bethe ansatz vector are divergent. Such solutions must be carefully regularized. We consider a regularization involving a parameter that can be. determined using a generalization of the Bethe equations. These generalized Bethe. equations provide a practical way of determining which singular solutions correspond. to eigenvectors of the model. The Bethe equations for the periodic XXX and XXZ spin chains admit singular. solutions, for which the corresponding eigenvalues and eigenvectors are ill-defined. We use a twist regularization to derive conditions for such singular solutions to bephysical, in which case they correspond to genuine eigenvalues and eigenvectors of. the Hamiltonian. We analyze the ground state of the open spin-1/2 isotropic quantum spin chain. with a non-diagonal boundary term using a recently proposed Bethe ansatz solution. As the coefficient of the non-diagonal boundary term tends to zero, the Bethe roots. split evenly into two sets: those that remain finite, and those that become infinite. We. argue that the former satisfy conventional Bethe equations, while the latter satisfy a. generalization of the Richardson-Gaudin equations. We derive an expression for the. leading correction to the boundary energy in terms of the boundary parameters. We argue that the Hamiltonians for A(2) 2n open quantum spin chains corresponding. to two choices of integrable boundary conditions have the symmetries Uq(Bn) and. Uq(Cn), respectively. The deformation of Cn is novel, with a nonstandard coproduct. We find a formula for the Dynkin labels of the Bethe states (which determine the degeneracies of the corresponding eigenvalues) in terms of the numbers of Bethe roots of. each type. With the help of this formula, we verify numerically (for a generic value of. the anisotropy parameter) that the degeneracies and multiplicities of the spectra implied by the quantum group symmetries are completely described by the Bethe ansatz.

Algebraic geometry and Bethe ansatz. Part I. The quotient ring for BAE

NASA Astrophysics Data System (ADS)

Jiang, Yunfeng; Zhang, Yang

2018-03-01

In this paper and upcoming ones, we initiate a systematic study of Bethe ansatz equations for integrable models by modern computational algebraic geometry. We show that algebraic geometry provides a natural mathematical language and powerful tools for understanding the structure of solution space of Bethe ansatz equations. In particular, we find novel efficient methods to count the number of solutions of Bethe ansatz equations based on Gröbner basis and quotient ring. We also develop analytical approach based on companion matrix to perform the sum of on-shell quantities over all physical solutions without solving Bethe ansatz equations explicitly. To demonstrate the power of our method, we revisit the completeness problem of Bethe ansatz of Heisenberg spin chain, and calculate the sum rules of OPE coefficients in planar N=4 super-Yang-Mills theory.

Exact diffusion constant in a lattice-gas wind-tree model on a Bethe lattice

NASA Astrophysics Data System (ADS)

Zhang, Guihua; Percus, J. K.

1992-02-01

Kong and Cohen [Phys. Rev. B 40, 4838 (1989)] obtained the diffusion constant of a lattice-gas wind-tree model in the Boltzmann approximation. The result is consistent with computer simulations for low tree concentration. In this Brief Report we find the exact diffusion constant of the model on a Bethe lattice, which turns out to be identical with the Kong-Cohen and Gunn-Ortuño results. Our interpretation is that the Boltzmann approximation is exact for this type of diffusion on a Bethe lattice in the same sense that the Bethe-Peierls approximation is exact for the Ising model on a Bethe lattice.

Where are the roots of the Bethe Ansatz equations?

NASA Astrophysics Data System (ADS)

Vieira, R. S.; Lima-Santos, A.

2015-10-01

Changing the variables in the Bethe Ansatz Equations (BAE) for the XXZ six-vertex model we had obtained a coupled system of polynomial equations. This provided a direct link between the BAE deduced from the Algebraic Bethe Ansatz (ABA) and the BAE arising from the Coordinate Bethe Ansatz (CBA). For two magnon states this polynomial system could be decoupled and the solutions given in terms of the roots of some self-inversive polynomials. From theorems concerning the distribution of the roots of self-inversive polynomials we made a thorough analysis of the two magnon states, which allowed us to find the location and multiplicity of the Bethe roots in the complex plane, to discuss the completeness and singularities of Bethe's equations, the ill-founded string-hypothesis concerning the location of their roots, as well as to find an interesting connection between the BAE with Salem's polynomials.

Polarimetry and Interferometry Applications

DTIC Science & Technology

2007-02-01

crown. Since for the traditional SAR interferometry only the total phase center of all scattering effects is relevant, the estimated height would be...the tree trunks and ground level. This contribution has its scattering phase center on the ground and is not present in the cross-polar channels...also the phase relations between the polarizations contain valuable information about the backscattering process. From the azimuth slices presented

Boundary perimeter Bethe ansatz

NASA Astrophysics Data System (ADS)

Frassek, Rouven

2017-06-01

We study the partition function of the six-vertex model in the rational limit on arbitrary Baxter lattices with reflecting boundary. Every such lattice is interpreted as an invariant of the twisted Yangian. This identification allows us to relate the partition function of the vertex model to the Bethe wave function of an open spin chain. We obtain the partition function in terms of creation operators on a reference state from the algebraic Bethe ansatz and as a sum of permutations and reflections from the coordinate Bethe ansatz.

Bethe states of the trigonometric SU(3) spin chain with generic open boundaries

NASA Astrophysics Data System (ADS)

Sun, Pei; Xin, Zhirong; Qiao, Yi; Wen, Fakai; Hao, Kun; Cao, Junpeng; Li, Guang-Liang; Yang, Tao; Yang, Wen-Li; Shi, Kangjie

2018-06-01

By combining the algebraic Bethe ansatz and the off-diagonal Bethe ansatz, we investigate the trigonometric SU (3) model with generic open boundaries. The eigenvalues of the transfer matrix are given in terms of an inhomogeneous T - Q relation, and the corresponding eigenstates are expressed in terms of nested Bethe-type eigenstates which have well-defined homogeneous limit. This exact solution provides a basis for further analyzing the thermodynamic properties and correlation functions of the anisotropic models associated with higher rank algebras.

A tale of two Bethe ansätze

NASA Astrophysics Data System (ADS)

Lima-Santos, Antonio; Nepomechie, Rafael I.; Pimenta, Rodrigo A.

2018-04-01

We revisit the construction of the eigenvectors of the single and double-row transfer matrices associated with the Zamolodchikov–Fateev model, within the algebraic Bethe ansatz method. The left and right eigenvectors are constructed using two different methods: the fusion technique and Tarasov’s construction. A simple explicit relation between the eigenvectors from the two Bethe ansätze is obtained. As a consequence, we obtain the Slavnov formula for the scalar product between on-shell and off-shell Tarasov–Bethe vectors.

Electron impact ionization cross section studies of C2Fx (x = 1 - 6) and C3Fx (x = 1 - 8) fluorocarbon species

NASA Astrophysics Data System (ADS)

Gupta, Dhanoj; Choi, Heechol; Song, Mi-Young; Karwasz, Grzegorz P.; Yoon, Jung-Sik

2017-05-01

The total ionization cross section for C2Fx (x = 1 - 6) and C3Fx (x = 1 - 8) fluorocarbon species are studied with the Binary-Encounter Bethe (BEB) model using various orbital parameters calculated from restricted/unrestricted Hartree-Fock (RHF/UHF) and Density Functional Theory (DFT). All the targets were optimized for their minimal structures and energies with several ab-initio methods with the aug-cc-pVTZ basis set. Among them, the present results with RHF/UHF orbital energies showed good agreement with the experimental results for stable targets C2F6, C2F4, C3F6 and C3F8. The results with the DFT (ωB97X/ωB97X-D) showed a reasonable agreement with the recent calculation of Bull et al. [J.N. Bull, M. Bart, C. Vallance, P.W. Harland, Phys. Rev. A 88, 062710 (2013)] for C2F6, C3F6 and C3F8 targets. The ionization cross section for C2F, C2F2, C2F3, C3F, C3F2, C3F3, C3F4, C3F5 and C3F7 were computed for the first time in the present study. We have also computed the vertical ionization potentials and polarizability for all the targets and compared them with other experimental and theoretical values. A good agreement is found between the present and the previous results. The calculated polarizability in turn is used to study the correlation with maximum ionization cross section and in general a good correlation is found among them, confirming the consistency and reliability of the present data. The cross section data reported in this article are very important for plasma modeling especially related to fluorocarbon plasmas. Contribution to the Topical Issue "Atomic and Molecular Data and their Applications", edited by Gordon W.F. Drake, Jung-Sik Yoon, Daiji Kato, Grzegorz Karwasz.

Electron collisions with methyl-substituted ethylenes: Cross section measurements and calculations for 2-methyl–2-butene and 2,3-dimethyl–2-butene

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

Szmytkowski, Czesław, E-mail: czsz@mif.pg.gda.pl; Stefanowska, Sylwia; Zawadzki, Mateusz

We report electron-scattering cross sections determined for 2-methyl–2-butene [(H{sub 3}C)HC = C(CH{sub 3}){sub 2}] and 2,3-dimethyl–2-butene [(H{sub 3}C){sub 2}C = C(CH{sub 3}){sub 2}] molecules. Absolute grand-total cross sections (TCSs) were measured for incident electron energies in the 0.5–300 eV range, using a linear electron-transmission technique. The experimental TCS energy dependences for the both targets appear to be very similar with respect to the shape. In each TCS curve, three features are discernible: the resonant-like structure located around 2.6–2.7 eV, the broad distinct enhancement peaking near 8.5 eV, and a weak hump in the vicinity of 24 eV. Theoretical integral elasticmore » (ECS) and ionization (ICS) cross sections were computed up to 3 keV by means of the additivity rule (AR) approximation and the binary-encounter-Bethe method, respectively. Their sums, (ECS+ICS), are in a reasonable agreement with the respective measured TCSs. To examine the effect of methylation of hydrogen sides in the ethylene [H{sub 2}C = CH{sub 2}] molecule on the TCS, we compared the TCS energy curves for the sequence of methylated ethylenes: propene [H{sub 2}C = CH(CH{sub 3})], 2-methylpropene [H{sub 2}C = C(CH{sub 3}){sub 2}], 2-methyl–2-butene [(H{sub 3}C)HC = C(CH{sub 3}){sub 2}], and 2,3-dimethyl–2-butene [(H{sub 3}C){sub 2}C = C(CH{sub 3}){sub 2}], measured in the same laboratory. Moreover, the isomeric effect is also discussed for the C{sub 5}H{sub 10} and C{sub 6}H{sub 12} compounds.« less

Theory of Raman scattering in coupled electron-phonon systems

NASA Astrophysics Data System (ADS)

Itai, K.

1992-01-01

The Raman spectrum is calculated for a coupled conduction-electron-phonon system in the zero-momentum-transfer limit. The Raman scattering is due to electron-hole excitations and phonons as well. The phonons of those branches that contribute to the electron self-energy and the correction of the electron-phonon vertex are assumed to have flat energy dispersion (the Einstein phonons). The effect of electron-impurity scattering is also incorporated. Both the electron-phonon interaction and the electron-impurity interaction cause the fluctuation of the electron distribution between different parts of the Fermi surface, which results in overdamped zero-sound modes of various symmetries. The scattering cross section is obtained by solving the Bethe-Salpeter equation. The spectrum shows a lower threshold at the smallest Einstein phonon energy when only the electron-phonon interaction is taken into consideration. When impurities are also taken into consideration, the threshold disappears.

Centenary Birth Anniversary of E. W. Beth (1908-1964)

ERIC Educational Resources Information Center

Bagni, Giorgio T.

2008-01-01

Evert Willem Beth (1908-1964) was a Dutch logician, mathematician and philosopher, whose work mainly concerned the foundations of mathematics. Beth was among the founders of the Commission Internationale pour l'Etude et l'Amelioration de l'Enseignement des Mathematiques and was a member of the Central Committee of the International Commission on…

Bethe vectors for XXX-spin chain

NASA Astrophysics Data System (ADS)

Burdík, Čestmír; Fuksa, Jan; Isaev, Alexei

2014-11-01

The paper deals with algebraic Bethe ansatz for XXX-spin chain. Generators of Yang-Baxter algebra are expressed in basis of free fermions and used to calculate explicit form of Bethe vectors. Their relation to N-component models is used to prove conjecture about their form in general. Some remarks on inhomogeneous XXX-spin chain are included.

Ionization Cross Sections and Dissociation Channels of DNA Bases by Electron Collisions

NASA Technical Reports Server (NTRS)

Huo, Winifred M.; Dateo, Christopher E.; Fletcher, Graham D.

2004-01-01

Free secondary electrons are the most abundant secondary species in ionizing radiation. Their role in DNA damage, both direct and indirect, is an active area of research. While indirect damage by free radicals, particularly by the hydroxyl radical generated by electron collision with water. is relatively well studied, damage by direct electron collision with DNA is less well understood. Only recently Boudaiffa et al. demonstrated that electrons at energies well below ionization thresholds can induce substantial yields of single- and double-strand breaks in DNA by a resonant, dissociative attachment process. This study attracted renewed interest in electron collisions with DNA, especially in the low energy region. At higher energies ionization becomes important. While Monte Carlo track simulations of radiation damage always include ionization, the probability of dissociative ionization, i.e., simultaneous ionization and dissociation, is ignored. Just like dissociative attachment, dissociative ionization may be an important contributor to double-strand breaks since the radicals and ions produced by dissociative ionization, located in the vicinity of the DNA coil, can readily interact with other parts of the DNA. Using the improved binary-encounter dipole (iBED) formulation, we calculated the ionization cross sections of the four DNA bases, adenine, cytosine, guanine, and thymine, by electrons at energies from threshold to 1 KeV. The present calculation gives cross sections approximately 20% lower than the results by Bemhardt and Paretzke using the Deutsch-Mark and Binary-Encounter-Bethe (BEB) formalisms. The difference is most likely due to the lack of a shielding term in the dipole potential used in the Deutsch-Mark and BEB formalisms. The dissociation channels of ionization for the bases are currently being studied.

Green Construction Initiatives in Overseas Contingency Operations

DTIC Science & Technology

2011-04-28

his recent deployment. 38 As the SOCCENT engineer, Lt Col Dwyer was responsible for O &M scope construction projects across the Middle East. He...construction, or Operations ·and Maintenance ( O &M) construction. Also in this section, I will explain applicabre sections of the governing documents...To my Pentagon friends and bosses: Colonel Beth Brown, Lieutenant Colonel Rick "Steve" Dwyer , Tom "PDT" Lowry and Major Todd Graham; thanks for

Accessing the real part of the forward elastic J/Psi-p and Phi-p threshold scattering amplitudes

NASA Astrophysics Data System (ADS)

Gryniuk, Oleksii; Vanderhaeghen, Marc

2017-09-01

We provide an updated analysis of the forward J / ψ -p scattering amplitude, relating its imaginary part to γp -> J / ψp and γp -> c c X cross section data, and calculating its real part through a once-subtracted dispersion relation. From a global fit to both differential and total cross section data, we extract a value for the spin-averaged J / ψ -p s-wave scattering length aψp = 0.046 +/- 0.005 fm, which can be translated into a J / ψ binding energy in nuclear matter Bψ = 2.7 +/- 0.3 MeV. We estimate the forward-backward asymmetry to the γp ->e-e+ p process around the J / ψ resonance, which results from interchanging the leptons in the interference between the J / ψ production and the Bethe-Heitler mechanisms. We show that this asymmetry can reach values around -25%. Its measurement can thus provide a very sensitive observable for a refined extraction of aψp. A preliminary analysis of the ϕ-p forward scattering led to the estimated forward-backward asymmetry reaching values of about -20% for the beam energies E = 2.2 , 4.4 GeV. The suitable kinematics were investigated for the specific setup of HMS and SHMS detectors of Hall C at JLab. Studies for the other JLab experiments (e.g. GlueX, SOLID) are ongoing.

Algebraic Bethe ansatz for the sℓ (2) Gaudin model with boundary

NASA Astrophysics Data System (ADS)

Cirilo António, N.; Manojlović, N.; Ragoucy, E.; Salom, I.

2015-04-01

Following Sklyanin's proposal in the periodic case, we derive the generating function of the Gaudin Hamiltonians with boundary terms. Our derivation is based on the quasi-classical expansion of the linear combination of the transfer matrix of the XXX Heisenberg spin chain and the central element, the so-called Sklyanin determinant. The corresponding Gaudin Hamiltonians with boundary terms are obtained as the residues of the generating function. By defining the appropriate Bethe vectors which yield strikingly simple off shell action of the generating function, we fully implement the algebraic Bethe ansatz, obtaining the spectrum of the generating function and the corresponding Bethe equations.

Remarks towards the spectrum of the Heisenberg spin chain type models

NASA Astrophysics Data System (ADS)

Burdík, Č.; Fuksa, J.; Isaev, A. P.; Krivonos, S. O.; Navrátil, O.

2015-05-01

The integrable close and open chain models can be formulated in terms of generators of the Hecke algebras. In this review paper, we describe in detail the Bethe ansatz for the XXX and the XXZ integrable close chain models. We find the Bethe vectors for two-component and inhomogeneous models. We also find the Bethe vectors for the fermionic realization of the integrable XXX and XXZ close chain models by means of the algebraic and coordinate Bethe ansatz. Special modification of the XXZ closed spin chain model ("small polaron model") is considered. Finally, we discuss some questions relating to the general open Hecke chain models.

Exclusive, hard diffraction in QCD

NASA Astrophysics Data System (ADS)

Freund, Andreas

In the first chapter we give an introduction to hard diffractive scattering in QCD to introduce basic concepts and terminology, thus setting the stage for the following chapters. In the second chapter we make predictions for nondiagonal parton distributions in a proton in the LLA. We calculate the DGLAP-type evolution kernels in the LLA, solve the nondiagonal GLAP evolution equations with a modified version of the CTEQ-package and comment on the range of applicability of the LLA in the asymmetric regime. We show that the nondiagonal gluon distribution g(x1,x2,t,μ2) can be well approximated at small x by the conventional gluon density xG(x,μ2). In the third chapter, we discuss the algorithms used in the LO evolution program for nondiagonal parton distributions in the DGLAP region and discuss the stability of the code. Furthermore, we demonstrate that we can reproduce the case of the LO diagonal evolution within less than 0.5% of the original code as developed by the CTEQ-collaboration. In chapter 4, we show that factorization holds for the deeply virtual Compton scattering amplitude in QCD, up to power suppressed terms, to all orders in perturbation theory. Furthermore, we show that the virtuality of the produced photon does not influence the general theorem. In chapter 5, we demonstrate that perturbative QCD allows one to calculate the absolute cross section of diffractive exclusive production of photons at large Q2 at HERA, while the aligned jet model allows one to estimate the cross section for intermediate Q2~2GeV2. Furthermore, we find that the imaginary part of the amplitude for the production of real photons is larger than the imaginary part of the corresponding DIS amplitude, leading to predictions of a significant counting rate for the current generation of experiments at HERA. We also find a large azimuthal angle asymmetry in ep scattering for HERA kinematics which allows one to directly measure the real part of the DVCS amplitude and hence the nondiagonal parton distributions. In the last chapter, we propose a new methodology of gaining shape fits to nondiagonal parton distributions and, for the first time, to determine the ratio η of the real to imaginary part of the DIS amplitude. We do this by using several recent fits to F2(x,Q2) to compute the asymmetry A for the combined DVCS and Bethe- Heitler cross section. The asymmetry A, isolates the interference term of DVCS and Bethe-Heitler in the total cross section, in other words, by isolating the real part of the DVCS amplitude through this asymmetry one has access to the nondiagonal parton distributions for the first time. Comparing the predictions for A against experiment would allow one to make a prediction of the shape, though not absolute value, of nondiagonal parton distributions. In the appendix, to illustrate an application of distributional methods as discussed in chapter 4, we will show, with the aid of simple examples, how to make simple estimates of the sizes of higher-order Feynman graphs. Our methods enable appropriate values of renormalization and factorization scales to be made. They allow the diagnosis of the source of unusually large corrections that are in need of resummation.

Field Testing and Load Rating Report, Bridge S-4360, Camp Hovey, South Korea

DTIC Science & Technology

2008-07-01

different section properties than the original six beam-lines. Shear stud connectors were specified on the design plans, indicating the deck was to be...the roadway wearing surface, the railings, and the conduits suspended from the bridge. Since the shear capacities were dependent only on the steel...load and live-load at Section G_Standard MCap 808.7 kN-m Superimposed dead-load applied to composite model— wearing surface and railing DW 75.69 kN

Obituary: Hans Albrecht Bethe, 1906-2005

NASA Astrophysics Data System (ADS)

Wijers, Ralph

2007-12-01

One of the unquestioned giants of physics and astrophysics, Hans Bethe, died on 6 March 2005, at the venerable age of 98, in his home town of Ithaca, New York. Seven decades of contributing to research and a Nobel Prize for his work on stellar hydrogen burning make a listing of his honors superfluous (besides being impossible in this space). Bethe was born in Strassburg, in then German Alsass Lothringen, on 2 July 1906. His father, Albrecht Julius Bethe (1872-1954), taught physiology at the University, and his mother, Anna Kuhn (1876-1966), was a musician and writer. Both his grandfathers were physicians. He spent his youth in Strassburg, Kiel, and Frankfurt, and some time in sanatoria due to tuberculosis. Hans's first scientific paper, at age 18, was with his father and a colleague, on dialysis. His education and early career in Germany brought him into contact with many top stars in the quantum revolution. Starting in Frankfurt in chemistry, Bethe soon switched to physics, taught there by Walter Gerlach and Karl Meissner, among others. In 1926, he successfully applied to join Arnold Sommerfeld's group in Munich, where he met one of his later long-term collaborators, Rudolf Peierls. Bethe considered his entry into physics to have come at an ideal time, with the new ideas of wave mechanics being developed and discussed right there; it was certainly also at an ideal place. His doctoral thesis was on the theory of electron diffraction by crystals, following the experimental work by Clinton Davisson and Lester Germer and the work on X-ray diffraction by Max von Laue and Paul Ewald. The newly minted doctor went from there briefly to Frankfurt and then to Ewald in Stuttgart, where he felt at home academically and personally. In 1939, Bethe would marry Ewald's daughter Rose. Not much later, though, Sommerfeld recalled him to Munich, where Sommerfeld created a Privatdozent position for him. There he worked out the solution for a linear chain of coupled spins by what we now call the "Bethe Ansatz." Soon after his acceptance of an assistant professorship at Tübingen in 1932, he had to flee Hitler's Germany because his mother was Jewish. Bethe went to the Bragg Institute in Manchester, England, where he worked again with Peierls. In 1934, Cornell University unexpectedly offered him a position as part of R. Clifton Gibbs's expansion of the physics department; he accepted and stayed there for the rest of his life. Right from the start, Bethe enjoyed America and its atmosphere very much. His first activity there was to write the "Bethe Bible": three articles in Reviews of Modern Physics to educate his colleagues in theoretical nuclear physics. Then he did the work that astrophysicists will still appreciate him most for, and which brought him the 1967 Nobel Prize. Having worked with George Gamow's student Charles Critchfield (at Gamow's suggestion) on the proton-proton chain for nuclear fusion in the Sun (published in 1938), Bethe was initially a bit discouraged with Arthur Eddington's estimates of the Solar core temperature; their calculations did not agree well with the observed solar luminosity. However, at the Washington conference in 1937, he heard of Strömgren's new estimates of the solar interior, which brought his and Critchfield's theory into much better agreement with the data. Fairly soon after the meeting, Bethe also worked out the process whereby more massive stars must accomplish hydrogen fusion, in what we now call the CNO cycle. Curiously, Bethe held up its publication briefly in order to compete for a prize for the best unpublished paper on energy production in stars. He did win, and used the money in part to bring his mother to the United States; eventually, the paper appeared in Physics Review in 1939, and founded a whole branch of astrophysics. The war brought Bethe to the Manhattan project, of which he became one of the intellectual leaders. He ploughed through problems theoretical and practical by attacking them head-on and not allowing himself to be side-tracked by those who would deem the problem be much more complex and difficult, moving straight forward like an intellectual battleship ("The H.A. Bethe Way," as his collaborator Gerald E. Brown would dub the style). Bethe's involvement in the Project brought to light his abilities in the managerial and political arena, which he used later to much effect to influence the wider world; he was among those who fought hard during the Cold War to contain the impact of the terrible weapons he had helped invent. As his two children, Henry and Monica, were born, the war years also made him a family man. As his father did with him, he often took them on long walks, in the hills around Ithaca or further afield; he much enjoyed walking, and mountains. Just after the war, during and following the June 1947 Shelter Island Conference, Bethe made another of his great contributions to physics—some might say his greatest. The experiments by Willis Lamb and Robert Retherford, on what came to be known as the "Lamb shift," were discussed, and during the meeting the assembled crowd (Richard Feynman, Julian Schwinger, and Hendrick Kramers among them) got stuck on the infinities of QED. During the train ride home, Bethe managed to compute the correct answer by realizing that the complex QED machinery could be bypassed, the H.A. Bethe Way. His 1967 Nobel Prize spurred a brief revival of Bethe's interest in astrophysics, but his work in the following years continued to focus on nuclear physics and dense matter (and disarmament and nuclear power, of course). In 1978 he re-entered astrophysics with a bang: Bethe was losing interest in nuclear physics and, after a few years of trying, Gerry Brown lured him back to astrophysics during a stay at the Nordic Institute for Theoretical Physics (NORDITA). The refugee from Hitler and the refugee from McCarthy jointly attacked the problem of supernova collapse. Bethe had the crucial insight that the low entropy of massive stellar cores would cause them to collapse to well above nuclear density, contrary to prevailing opinion. With James Applegate and James Lattimer, they published their finding in the BBAL ('"babble") paper of 1979. After that, astrophysics never quite left Bethe again, and with Brown (his "junior collaborator"), he took an interest in the fate of massive stars and black holes more generally. The series of papers on formation of black holes, gamma-ray bursts, and gravity-wave sources continued until close to his death. These papers are done very much the H.A. Bethe Way, often finding simple approximations to much more complicated work of others, and are quite straightforward. An inevitable part of the Bethe-Brown collaboration was a January stay in California; during the 1999 edition I had the good fortune of becoming a small footnote to the great Bethe story. Gerry and Hans invited me to join them for a while, to discuss issues of binary star evolution and population synthesis. I have to admit to being rather taken aback by the way in which the 93-year old gave me a good intellectual runaround every day. And yet, as many others have commented, there was nothing facetious or overbearing in his manner: He made me feel like a valuable colleague and welcome guest. Good meals were an essential part of Hans's every day, and during a dinner prepared by Rose Bethe and Betty Brown, the old stories surfaced. I could not resist asking about the legendary story of Rose and Hans's evening walk under the stars. Hans, so says the story, tried to impress his fiancée by commenting that at that moment, he was probably the only person on Earth who understood why the stars shine. Hans grinned a bit sheepishly, but Rose roundly confirmed the story with a big smile. Not too impressed, she had replied: "That's nice." And so it was.

Large-N and Bethe Ansatz

NASA Astrophysics Data System (ADS)

Jurčo, Branislav

We describe an integrable model, related to the Gaudin magnet, and its relation to the matrix model of Brézin, Itzykson, Parisi and Zuber. Relation is based on Bethe ansatz for the integrable model and its interpretation using orthogonal polynomials and saddle point approximation. Large-N limit of the matrix model corresponds to the thermodynamic limit of the integrable system. In this limit (functional) Bethe ansatz is the same as the generating function for correlators of the matrix models.

Proceedings of the Annual Meeting of the Association for Education in Journalism and Mass Communication (78th, Washington, DC, August 9-12, 1995). Advertising Division.

ERIC Educational Resources Information Center

Association for Education in Journalism and Mass Communication.

The advertising section of the Proceedings contains the following 14 papers: "Advertising versus Product Publicity: The Effects on Credibility and Purchase Intent" (M. Catherine Chew and others); "Introducing Introductory Advertising Students to the World Wide Web" (Beth E. Barnes); "In Defense of Puffery" (John H.…

Algebraic Bethe ansatz for the two species ASEP with different hopping rates

NASA Astrophysics Data System (ADS)

Cantini, Luigi

2008-03-01

An ASEP with two species of particles and different hopping rates is considered on a ring. Its integrability is proved, and the nested algebraic Bethe ansatz is used to derive the Bethe equations for states with arbitrary numbers of particles of each type, generalizing the results of Derrida and Evans [10]. We also present formulae for the total velocity of particles of a given type and their limit given the large size of the system and the finite densities of the particles.

Bethe ansatz for two-magnon scattering states in 2D and 3D Heisenberg–Ising ferromagnets

NASA Astrophysics Data System (ADS)

Bibikov, P. N.

2018-04-01

Two different versions of Bethe ansatz are suggested for evaluation of scattering two-magnon states in 2D and 3D Heisenberg–Ising ferromagnets on square and simple cubic lattices. It is shown that the two-magnon sector is subdivided on two subsectors related to non-interacting and scattering magnons. The former subsector possess an integrable regular dynamics and may be described by a natural modification of the usual Bethe Ansatz. The latter one is characterized by a non-integrable chaotic dynamics and may be treated only within discrete degenerative version of Bethe Ansatz previously suggested by the author. Some of these results are generalized for multi-magnon states of the Heisenberg–Ising ferromagnet on a D dimensional hyper cubic lattice. Dedicated to the memory of L D Faddeev.

Degeneration of Bethe subalgebras in the Yangian of gl_n

NASA Astrophysics Data System (ADS)

Ilin, Aleksei; Rybnikov, Leonid

2018-04-01

We study degenerations of Bethe subalgebras B( C) in the Yangian Y(gl_n), where C is a regular diagonal matrix. We show that closure of the parameter space of the family of Bethe subalgebras, which parameterizes all possible degenerations, is the Deligne-Mumford moduli space of stable rational curves \\overline{M_{0,n+2}}. All subalgebras corresponding to the points of \\overline{M_{0,n+2}} are free and maximal commutative. We describe explicitly the "simplest" degenerations and show that every degeneration is the composition of the simplest ones. The Deligne-Mumford space \\overline{M_{0,n+2}} generalizes to other root systems as some De Concini-Procesi resolution of some toric variety. We state a conjecture generalizing our results to Bethe subalgebras in the Yangian of arbitrary simple Lie algebra in terms of this De Concini-Procesi resolution.

Proceedings of the Annual Meeting of the Association for Education in Journalism and Mass Communication (80th, Chicago, Illinois, July 30-August 2, 1997): History.

ERIC Educational Resources Information Center

Association for Education in Journalism and Mass Communication.

The History section of the Proceedings contains the following 12 papers: "Change on Tap for Nashville: The Telegraph and News Content, 1860" (Frank E. Fee, Jr.); "Rod Sterling's 'Hegemony Zone'" (Bob Pondillo); "The Publications of the Carlisle Indian School: Cultural Voices or Pure Propaganda?" (Beth A. Haller);…

Proceedings of the Annual Meeting of the Association for Education in Journalism and Mass Communication (83rd, Phoenix, Arizona, August 9-12, 2000). Miscellaneous, Part III.

ERIC Educational Resources Information Center

Association for Education in Journalism and Mass Communication.

The Miscellaneous, part III section of the proceedings contains the following 11 papers: "The Relationship between Health and Fitness Magazine Reading and Eating-Disordered Weight-Loss Methods among High School Girls" (Steven R. Thomsen, Michelle M. Weber, and Lora Beth Brown); "A Practical Exercise for Teaching Ethical Decision…

Proceedings of the Annual Meeting of the Association for Education in Journalism and Mass Communication (80th, Chicago, Illinois, July 30-August 2, 1997): Advertising.

ERIC Educational Resources Information Center

Association for Education in Journalism and Mass Communication.

The Advertising section of the Proceedings contains the following 13 papers: "Offering a Creative Track in the Advertising Major: A Case History" (Beth E. Barnes and Carla V. Lloyd); "Messages of Individualism in French, Spanish, and American Television Advertising" (Ronald E. Taylor and Joyce Wolburg); "Frequency Levels…

A Test of Thick-Target Nonuniform Ionization as an Explanation for Breaks in Solar Flare Hard X-Ray Spectra

NASA Technical Reports Server (NTRS)

Holman, gordon; Dennis Brian R.; Tolbert, Anne K.; Schwartz, Richard

2010-01-01

Solar nonthermal hard X-ray (HXR) flare spectra often cannot be fitted by a single power law, but rather require a downward break in the photon spectrum. A possible explanation for this spectral break is nonuniform ionization in the emission region. We have developed a computer code to calculate the photon spectrum from electrons with a power-law distribution injected into a thick-target in which the ionization decreases linearly from 100% to zero. We use the bremsstrahlung cross-section from Haug (1997), which closely approximates the full relativistic Bethe-Heitler cross-section, and compare photon spectra computed from this model with those obtained by Kontar, Brown and McArthur (2002), who used a step-function ionization model and the Kramers approximation to the cross-section. We find that for HXR spectra from a target with nonuniform ionization, the difference (Delta-gamma) between the power-law indexes above and below the break has an upper limit between approx.0.2 and 0.7 that depends on the power-law index delta of the injected electron distribution. A broken power-law spectrum with a. higher value of Delta-gamma cannot result from nonuniform ionization alone. The model is applied to spectra obtained around the peak times of 20 flares observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI from 2002 to 2004 to determine whether thick-target nonuniform ionization can explain the measured spectral breaks. A Monte Carlo method is used to determine the uncertainties of the best-fit parameters, especially on Delta-gamma. We find that 15 of the 20 flare spectra require a downward spectral break and that at least 6 of these could not be explained by nonuniform ionization alone because they had values of Delta-gamma with less than a 2.5% probability of being consistent with the computed upper limits from the model. The remaining 9 flare spectra, based on this criterion, are consistent with the nonuniform ionization model.

Bayesian extraction of the parton distribution amplitude from the Bethe-Salpeter wave function

NASA Astrophysics Data System (ADS)

Gao, Fei; Chang, Lei; Liu, Yu-xin

2017-07-01

We propose a new numerical method to compute the parton distribution amplitude (PDA) from the Euclidean Bethe-Salpeter wave function. The essential step is to extract the weight function in the Nakanishi representation of the Bethe-Salpeter wave function in Euclidean space, which is an ill-posed inversion problem, via the maximum entropy method (MEM). The Nakanishi weight function as well as the corresponding light-front parton distribution amplitude (PDA) can be well determined. We confirm prior work on PDA computations, which was based on different methods.

In Memoriam: Hans Bethe

NASA Astrophysics Data System (ADS)

Garwin, Richard L.; Von Hippel, Frank

Hans Bethe, who died on March 6 at the age of 98, was exemplary as a scientist; a citizen-advocate seeking to stem the arms race; and an individual of warmth, generosity, tenacity, and modest habits. Bethe made major contributions to several areas of physics during his academic career. He earned a Nobel Prize in 1967 for his research into how the sun generates its energy by converting hydrogen to helium using carbon as a nuclear catalyst. A few years later, he made central contributions to the secret US World War II nuclear-weapon development programs (the "Manhattan Project").

Clinical trials of boron neutron capture therapy [in humans] [at Beth Israel Deaconess Medical Center][at Brookhaven National Laboratory

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

Wallace, Christine

2001-05-29

Assessment of research records of Boron Neutron Capture Therapy was conducted at Brookhaven National Laboratory and Beth Israel Deaconess Medical Center using the Code of Federal Regulations, FDA Regulations and Good Clinical Practice Guidelines. Clinical data were collected from subjects' research charts, and differences in conduct of studies at both centers were examined. Records maintained at Brookhaven National Laboratory were not in compliance with regulatory standards. Beth Israel's records followed federal regulations. Deficiencies discovered at both sites are discussed in the reports.

Boundary Quantum Knizhnik-Zamolodchikov Equations and Bethe Vectors

NASA Astrophysics Data System (ADS)

Reshetikhin, Nicolai; Stokman, Jasper; Vlaar, Bart

2015-06-01

Solutions to boundary quantum Knizhnik-Zamolodchikov equations are constructed as bilateral sums involving "off-shell" Bethe vectors in case the reflection matrix is diagonal and only the 2-dimensional representation of is involved. We also consider their rational and classical degenerations.

Height probabilities in the Abelian sandpile model on the generalized finite Bethe lattice

NASA Astrophysics Data System (ADS)

Chen, Haiyan; Zhang, Fuji

2013-08-01

In this paper, we study the sandpile model on the generalized finite Bethe lattice with a particular boundary condition. Using a combinatorial method, we give the exact expressions for all single-site probabilities and some two-site joint probabilities. As a by-product, we prove that the height probabilities of bulk vertices are all the same for the Bethe lattice with certain given boundary condition, which was found from numerical evidence by Grassberger and Manna ["Some more sandpiles," J. Phys. (France) 51, 1077-1098 (1990)], 10.1051/jphys:0199000510110107700 but without a proof.

Yong-Ki Kim — His Life and Recent Work

NASA Astrophysics Data System (ADS)

Stone, Philip M.

2007-08-01

Dr. Kim made internationally recognized contributions in many areas of atomic physics research and applications, and was still very active when he was killed in an automobile accident. He joined NIST in 1983 after 17 years at the Argonne National Laboratory following his Ph.D. work at the University of Chicago. Much of his early work at Argonne and especially at NIST was the elucidation and detailed analysis of the structure of highly charged ions. He developed a sophisticated, fully relativistic atomic structure theory that accurately predicts atomic energy levels, transition wavelengths, lifetimes, and transition probabilities for a large number of ions. This information has been vital to model the properties of the hot interior of fusion research plasmas, where atomic ions must be described with relativistic atomic structure calculations. In recent years, Dr. Kim worked on the precise calculation of ionization and excitation cross sections of numerous atoms, ions, and molecules that are important in fusion research and in plasma processing for manufacturing semiconductor chips. Dr. Kim greatly advanced the state-of-the-art of calculations for these cross sections through development and implementation of highly innovative methods, including his Binary-Encounter-Bethe (BEB) theory and a scaled plane wave Born (scaled PWB) theory. His methods, using closed quantum mechanical formulas and no adjustable parameters, avoid tedious large-scale computations with main-frame computers. His calculations closely reproduce the results of benchmark experiments as well as large-scale calculations requiring hours of computer time. This recent work on BEB and scaled PWB is reviewed and examples of its capabilities are shown.

Electron induced ionization of plasma processing gases: C4F x (x  =  1–8) and the isomers of C4F6 and C4F8

NASA Astrophysics Data System (ADS)

Gupta, Dhanoj; Choi, Heechol; Kwon, Deuk-Chul; Yoon, Jung-Sik; Song, Mi-Young

2018-04-01

The total ionization cross section (Q ion) for C4F x (x  =  1–8) fluorocarbons and the isomers of C4F6 and C4F8 molecules are calculated from ionization threshold to 5 keV using the binary-encounter bethe method. The targets are fully optimized using the Hartree–Fock (HF) method and density function theory (DFT) for their minimum energy structure and orbital parameters. The present Q ion with HF parameters showed good agreement with the experimental data for 1,3-C4F6, 2-C4F6, 2-C4F8 and 1-C4F8. On the other hand, the Q ion with DFT parameters are in good accordance with the recent theoretical results for 1,3-C4F6 and 2-C4F6. The Q ion for c-C4F8 showed much variation among the various results. The isomer effect in Q ion is negligible for the isomers of C4F6 and C4F8 molecules. The calculation of Q ion for C4F, C4F2, C4F3, C4F4, C4F5, c-C4F6, C4F7 and iso-C4F8 is a maiden attempt. The present cross section data are important quantities for low temperature plasma modeling especially related to the fluorocarbon plasmas.

Bethe Ansatz solutions for highest states in Script N = 4 SYM and AdS/CFT duality

NASA Astrophysics Data System (ADS)

Beccaria, Matteo; DelDebbio, Luigi

2006-09-01

We consider the operators with highest anomalous dimension Δ in the compact rank-one sectors fraktur sfraktur u(1|1) and fraktur sfraktur u(2) of Script N = 4 super Yang-Mills. We study the flow of Δ from weak to strong 't Hooft coupling λ by solving (i) the all-loop gauge Bethe Ansatz, (ii) the quantum string Bethe Ansatz. The two calculations are carefully compared in the strong coupling limit and exhibit different exponents ν in the leading order expansion Δ ~ λν. We find ν = 1/2 and ν = 1/4 for the gauge or string solution. This strong coupling discrepancy is not unexpected, and it provides an explicit example where the gauge Bethe Ansatz solution cannot be trusted at large λ. Instead, the string solution perfectly reproduces the Gubser-Klebanov-Polyakov law Δ = 2n1/2 λ1/4. In particular, we provide an analytic expression for the integer level n as a function of the U(1) charge in both sectors.

Quantum group symmetries and completeness for \\boldsymbol {A}_{\\boldsymbol {2n}}^{\\boldsymbol{(2)}} open spin chains

NASA Astrophysics Data System (ADS)

Ahmed, Ibrahim; Nepomechie, Rafael I.; Wang, Chunguang

2017-07-01

We argue that the Hamiltonians for A(2)2n open quantum spin chains corresponding to two choices of integrable boundary conditions have the symmetries Uq(Bn) and Uq(Cn) , respectively. We find a formula for the Dynkin labels of the Bethe states (which determine the degeneracies of the corresponding eigenvalues) in terms of the numbers of Bethe roots of each type. With the help of this formula, we verify numerically (for a generic value of the anisotropy parameter) that the degeneracies and multiplicities of the spectra implied by the quantum group symmetries are completely described by the Bethe ansatz.

Study of molecular N D bound states in the Bethe-Salpeter equation approach

NASA Astrophysics Data System (ADS)

Wang, Zhen-Yang; Qi, Jing-Juan; Guo, Xin-Heng; Wei, Ke-Wei

2018-05-01

We study the Λc(2595 )+ and Σc(2800 )0 states as the N D bound systems in the Bethe-Salpeter formalism in the ladder and instantaneous approximations. With the kernel induced by ρ , ω and σ exchanges, we solve the Bethe-Salpeter equations for the N D bound systems numerically and find that the bound states may exist. We assume that the observed states Λc(2595 )+ and Σc(2800 )0 are S -wave N D molecular bound states and calculate the decay widths of Λc(2595 )+→Σc0π+ and Σc(2800 )0→Λc+π-.

Combinatorics of Generalized Bethe Equations

NASA Astrophysics Data System (ADS)

Kozlowski, Karol K.; Sklyanin, Evgeny K.

2013-10-01

A generalization of the Bethe ansatz equations is studied, where a scalar two-particle S-matrix has several zeroes and poles in the complex plane, as opposed to the ordinary single pole/zero case. For the repulsive case (no complex roots), the main result is the enumeration of all distinct solutions to the Bethe equations in terms of the Fuss-Catalan numbers. Two new combinatorial interpretations of the Fuss-Catalan and related numbers are obtained. On the one hand, they count regular orbits of the permutation group in certain factor modules over {{Z}^M}, and on the other hand, they count integer points in certain M-dimensional polytopes.

Beth Reis and the Safe Schools Coalition

ERIC Educational Resources Information Center

Vaught, Sabina E.

2007-01-01

This article chronicles the formation and organization of the Safe Schools Coalition (SCC) through the experiences of Beth Reis, co-founder and co-Chair. The article suggests ways in which the SCC can serve as a model for both collective and individual work in promoting safe schools.

Review of “orthopaedic biomechanics” edited by Beth A. Winkelstein

PubMed Central

2013-01-01

This article is a review of the book “orthopaedic biomechanics” edited by Beth A. Winkelstein. This book (hardcover) was published by CRC Press, Taylor & Francis Group, FL in 2012. The contents of the book and its relevance to orthopedic research or practice is discussed in this invited review.

Numerical studies of the Bethe-Salpeter equation for a two-fermion bound state

NASA Astrophysics Data System (ADS)

de Paula, W.; Frederico, T.; Salmè, G.; Viviani, M.

2018-03-01

Some recent advances on the solution of the Bethe-Salpeter equation (BSE) for a two-fermion bound system directly in Minkowski space are presented. The calculations are based on the expression of the Bethe-Salpeter amplitude in terms of the so-called Nakanishi integral representation and on the light-front projection (i.e. the integration of the light-front variable k - = k 0 - k 3). The latter technique allows for the analytically exact treatment of the singularities plaguing the two-fermion BSE in Minkowski space. The good agreement observed between our results and those obtained using other existing numerical methods, based on both Minkowski and Euclidean space techniques, fully corroborate our analytical treatment.

Hospital CIO Explains Blockchain Potential: An Interview with Beth Israel Deaconess Medical Center's John Halamka.

PubMed

Mertz, Leslie

2018-01-01

Work is already underway to bring blockchain technology to the healthcare industry, and hospital administrators are trying to figure out what it can do for them, their clinicians, and their patients. That includes administrators at Beth Israel Deaconess Medical Center, a leading academic medical center located in Boston.

On quantum integrable models related to nonlinear quantum optics. An algebraic Bethe ansatz approach

NASA Astrophysics Data System (ADS)

Jurčo, Branislav

1989-08-01

A unified approach based on Bethe ansatz in a large variety of integrable models in quantum optics is given. Second harmonics generation, three-boson interaction, the Dicke model, and some cases of four-boson interaction as special cases of su(2)⊕su(1,1)-Gaudin models are included.

Twisting singular solutions of Betheʼs equations

NASA Astrophysics Data System (ADS)

Nepomechie, Rafael I.; Wang, Chunguang

2014-12-01

The Bethe equations for the periodic XXX and XXZ spin chains admit singular solutions, for which the corresponding eigenvalues and eigenvectors are ill-defined. We use a twist regularization to derive conditions for such singular solutions to be physical, in which case they correspond to genuine eigenvalues and eigenvectors of the Hamiltonian.

A generalized Uhlenbeck and Beth formula for the third cluster coefficient

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

Larsen, Sigurd Yves; Lassaut, Monique; Amaya-Tapia, Alejandro, E-mail: jano@icf.unam.mx

2016-11-15

Relatively recently (Amaya-Tapia et al., 2011), we presented a formula for the evaluation of the third Bose fugacity coefficient–leading to the third virial coefficient–in terms of three-body eigenphase shifts, for particles subject to repulsive forces. An analytical calculation for a 1-dim. model, for which the result is known, confirmed the validity of this approach. We now extend the formalism to particles with attractive forces, and therefore must allow for the possibility that the particles have bound states. We thus obtain a true generalization of the famous formula of Uhlenbeck and Beth (Uhlenbeck and Beth, 1936; Beth and Uhlenbeck, 1937) and ofmore » Gropper (Gropper, 1936, 1937) for the second virial. We illustrate our formalism by a calculation, in an adiabatic approximation, of the third cluster in one dimension, using McGuire’s model as in our previous paper, but with attractive forces. The inclusion of three-body bound states is trivial; taking into account states having asymptotically two particles bound, and one free, is not.« less

The Role of Protein Kinase D (PKD) Signaling in Breast Cancer Cell Migration and Invasion

DTIC Science & Technology

2010-09-01

CONTRACTING ORGANIZATION: Beth Israel Deaconess Med Center Boston, MA 02215...PERFORMING ORGANIZATION REPORT NUMBER Beth Israel Deaconess Medical Center Boston, MA 02215 9. SPONSORING / MONITORING AGENCY...species including fish , flies and worms (Figure 8A). A distinct putative PKD consensus phosphorylation motif on Rabaptin-5 is also found at Ser162

Track structure in radiation biology: theory and applications.

PubMed

Nikjoo, H; Uehara, S; Wilson, W E; Hoshi, M; Goodhead, D T

1998-04-01

A brief review is presented of the basic concepts in track structure and the relative merit of various theoretical approaches adopted in Monte-Carlo track-structure codes are examined. In the second part of the paper, a formal cluster analysis is introduced to calculate cluster-distance distributions. Total experimental ionization cross-sections were least-square fitted and compared with the calculation by various theoretical methods. Monte-Carlo track-structure code Kurbuc was used to examine and compare the spectrum of the secondary electrons generated by using functions given by Born-Bethe, Jain-Khare, Gryzinsky, Kim-Rudd, Mott and Vriens' theories. The cluster analysis in track structure was carried out using the k-means method and Hartigan algorithm. Data are presented on experimental and calculated total ionization cross-sections: inverse mean free path (IMFP) as a function of electron energy used in Monte-Carlo track-structure codes; the spectrum of secondary electrons generated by different functions for 500 eV primary electrons; cluster analysis for 4 MeV and 20 MeV alpha-particles in terms of the frequency of total cluster energy to the root-mean-square (rms) radius of the cluster and differential distance distributions for a pair of clusters; and finally relative frequency distribution for energy deposited in DNA, single-strand break and double-strand breaks for 10MeV/u protons, alpha-particles and carbon ions. There are a number of Monte-Carlo track-structure codes that have been developed independently and the bench-marking presented in this paper allows a better choice of the theoretical method adopted in a track-structure code to be made. A systematic bench-marking of cross-sections and spectra of the secondary electrons shows differences between the codes at atomic level, but such differences are not significant in biophysical modelling at the macromolecular level. Clustered-damage evaluation shows: that a substantial proportion of dose ( 30%) is deposited by low-energy electrons; the majority of DNA damage lesions are of simple type; the complexity of damage increases with increased LET, while the total yield of strand breaks remains constant; and at high LET values nearly 70% of all double-strand breaks are of complex type.

Low energy electron-impact study of AlO using the R-matrix method

NASA Astrophysics Data System (ADS)

Kaur, Savinder; Baluja, Kasturi L.; Bassi, Monika

2017-11-01

This comprehensive study reports the electron-impact on the open shell AlO molecule at low energy (less than 10 eV) using the R-matrix method. We present the elastic (integrated and differential), momentum-transfer, electronic excitation and ionisation cross sections; along with effective collision frequency over a wide electron temperature range (1000-100 000 K). Correlations via a configuration interaction technique are used to represent the target states. Calculations are performed in the static-exchange and 24-target states close-coupling approximation at the experimental bond length of 1.6178 Å. We have used different basis sets 6-311G*, double zeta, polarization (DZP), cc-pCVTZ to represent our target states. We have chosen the Gaussian Type Orbitals (GTOs) basis set DZP to represent the atomic orbitals which gave the best one-electron properties of the molecule. The calculated dipole moment (1.713 au), rotational constant (0.641399 cm-1) and the vertical excitation energies are in concurrence with the best available data. The continuum electron is also represented by GTOs and is placed at the center of mass of the molecule. Resonance analysis is carried out to assign the resonance parameters and the parentage of detected resonances by fitting the eigenphase sums to the Breit-Wigner profile. Our study has detected three core-excited shape resonances in the 24-state model. We detect a stable bound state of AlO- of 1 A 1 symmetry having configuration 1 σ 2 … 7 σ 21 π 42 π 4 with a vertical electronic affinity value of 2.59 eV which is in good accord with the experimental value of 2.6 ± (0.01) eV. The ionisation cross sections are calculated using the Binary-Encounter-Bethe Model in which Hartree-Fock molecular orbitals at self-consistent level are used to calculate kinetic and binding energies of the occupied molecular orbitals. We include partial waves up to g-wave beyond which Born closure method is employed to obtain converged cross sections.

New Data for Modeling Hypersonic Entry into Earth's Atmosphere: Electron-impact Ionization of Atomic Nitrogen

NASA Astrophysics Data System (ADS)

Savin, Daniel Wolf; Ciccarino, Christopher

2017-06-01

Meteors passing through Earth’s atmosphere and space vehicles returning to Earth from beyond orbit enter the atmosphere at hypersonic velocities (greater than Mach 5). The resulting shock front generates a high temperature reactive plasma around the meteor or vehicle (with temperatures greater than 10,000 K). This intense heat is transferred to the entering object by radiative and convective processes. Modeling the processes a meteor undergoes as it passes through the atmosphere and designing vehicles to withstand these conditions requires an accurate understanding of the underlying non-equilibrium high temperature chemistry. Nitrogen chemistry is particularly important given the abundance of nitrogen in Earth's atmosphere. Line emission by atomic nitrogen is a major source of radiative heating during atomspheric entry. Our ability to accurately calculate this heating is hindered by uncertainties in the electron-impact ionization (EII) rate coefficient for atomic nitrogen.Here we present new EII calculations for atomic nitrogen. The atom is treated as a 69 level system, incorporating Rydberg values up to n=20. Level-specific cross sections are from published B-Spline R-Matrix-with-Pseudostates results for the first three levels and binary-encounter Bethe (BEB) calculations that we have carried out for the remaining 59 levels. These cross section data have been convolved into level-specific rate coefficients and fit with the commonly-used Arrhenius-Kooij formula for ease of use in hypersonic chemical models. The rate coefficient data can be readily scaled by the relevant atomic nitrogen partition function which varies in time and space around the meteor or reentry vehicle. Providing data up to n=20 also enables modelers to account for the density-dependent lowering of the continuum.

Timelike Compton Scattering off the nucleon: observables and experimental perspectives for JLab at 12 GeV

NASA Astrophysics Data System (ADS)

Boër, Marie

2016-03-01

Hard exclusive processes such as photoproduction or electroproduction of photon or meson off the nucleon provide access to the Generalized Parton Distributions (GPDs), in the regime where the scattering amplitude is factorized into a hard and a soft part. GPDs contain the correlation between the longitudinal momentum fraction and the transverse spatial densities of quarks and gluons in the nucleon. Timelike Compton Scattering (TCS) correspond to the reaction γN → γ*N → e+e-N, where the photon is scattered off a quark. It is measured through its interference with the associated Bethe-Heitler process, which has the same final state. TCS allows to access the GPDs and test their universality by comparison to the results obtained with the DVCS process (eN → eγN). Also, results obtained with TCS provide additional independent constrains to the GPDs parameterization. We will present the physical motivations for TCS, with our theoretical predictions for TCS observables and their dependencies. We calculated for JLab 12 GeV energies all the single and double beam and/or target polarization observables off the proton and off the neutron. We will also present the experimental perspectives for the next years at JLab. Two proposals were already accepted at JLab: in Hall B, with the CLAS12 spectrometer, in order to measure the unpolarized cross section and in Hall A, with the SoLID spectrometer, in order to measure the unpolarized cross section and the beam spin asymmetry at high intensity. A Letter Of Intent was also submitted in order to measure the transverse target spin asymmetries in Hall C. We will discuss the merits of this different experiments and present some of the expected results.

Megawatt Space Power Conditioning, Distribution, and Control Study

DTIC Science & Technology

1988-03-01

also must be given to the design of an ac transmission line for this relatively high frequency . 2.3.2 Medium High Voltage Systems. Figure 2-4 shows a...systems are designed to exploit the use of 2 MW klystrode tubes (see Section 3.1) which require a dc voltage of about 140 kV. This high voltage can be...the concerns is that to date there have been no three-phase high voltage, high frequency transmission lines designed . Figure 5-6. While the previous

Advancement of High Resolution Radar Polarimetry in Target Verses Clutter Detection, Discrimination, Classification: A. Basic Theory and Modeling of Polarimetric Clutter Phenomenology.

DTIC Science & Technology

1988-07-15

the interim period, polarimetLic measurement data collected at other DOD/NATO/Industrial R/D/M facilities will be used. These basic studies will be...the polarization sphere and its spread can he related either to the coherency factor or the depolarization factor plus descriptive parameters of the...careful study of the concluding sections outlining the overall scenario of solved and unsolved problems. Here, we also refer to the recent report (Dec

Stennis Day Camper

NASA Technical Reports Server (NTRS)

2005-01-01

Sara Beth Casey, 5, proudly displays her artwork, 'Planets.' Sara Beth created the art as a student of Stennis Day Camp, a free camp for Stennis Space Center employees' children whose schools have not resumed since Hurricane Katrina hit the region on Aug. 29. The camp has registered nearly 200 children and averages 100 children each day. The camp will continue until all schools are back in session.

Stennis Day Camper

NASA Image and Video Library

2005-10-05

Sara Beth Casey, 5, proudly displays her artwork, 'Planets.' Sara Beth created the art as a student of Stennis Day Camp, a free camp for Stennis Space Center employees' children whose schools have not resumed since Hurricane Katrina hit the region on Aug. 29. The camp has registered nearly 200 children and averages 100 children each day. The camp will continue until all schools are back in session.

Hans Bethe's early life

NASA Astrophysics Data System (ADS)

Bernstein, Jeremy

2012-10-01

In 1937, two years after he moved to the US to escape Nazi persecution, the physicist Hans Bethe sent a letter to his mother in Germany. In it, he wrote, "I think I am about the leading theoretician in America. [Eugene] Wigner is certainly better and [Robert] Oppenheimer and [Edward] Teller probably just as good. But I do more and talk more and that counts too."

A Conversation with Hans Bethe

NASA Astrophysics Data System (ADS)

Goodstein, Judith

1999-10-01

A Nobel laureate in physics speaks candidly about C. C. Lauritsen, Robert Millikan, and a number of other prominent physicists he has known and worked with at Cornell University, the California Institute of Technology, and the University of Rome. Bethe also describes his first impressions of nuclear physics, the political climate in Italy in the 1930s, and the Rome school of physics.

Connecting and Collaborating within and beyond a Massive Open Online Course

ERIC Educational Resources Information Center

Pytash, Kristine E.; Hicks, Troy; Ferdig, Richard E.

2016-01-01

In this article, we draw on the experiences of two young adults, Beth and Jamie (pseudonyms), who participated in a connectivist Massive Open Online Course (cMOOC) to explore how adolescents can become active members in a community of learners and the digital literacy practices that support this entry. We argue that Beth and Jamie engaged in…

Exact ground-state correlation functions of an atomic-molecular Bose–Einstein condensate model

NASA Astrophysics Data System (ADS)

Links, Jon; Shen, Yibing

2018-05-01

We study the ground-state properties of an atomic-molecular Bose–Einstein condensate model through an exact Bethe Ansatz solution. For a certain range of parameter choices, we prove that the ground-state Bethe roots lie on the positive real-axis. We then use a continuum limit approach to obtain a singular integral equation characterising the distribution of these Bethe roots. Solving this equation leads to an analytic expression for the ground-state energy. The form of the expression is consistent with the existence of a line of quantum phase transitions, which has been identified in earlier studies. This line demarcates a molecular phase from a mixed phase. Certain correlation functions, which characterise these phases, are then obtained through the Hellmann–Feynman theorem.

Random Blume-Emery-Griffiths model on the Bethe lattice

NASA Astrophysics Data System (ADS)

Albayrak, Erhan

2015-12-01

The random phase transitions of the Blume-Emery-Griffiths (BEG) model for the spin-1 system are investigated on the Bethe lattice and the phase diagrams of the model are obtained. The biquadratic exchange interaction (K) is turned on, i.e. the BEG model, with probability p either attractively (K > 0) or repulsively (K < 0) and turned off, which leads to the BC model, with the probability (1 - p) throughout the Bethe lattice. By taking the bilinear exchange interaction parameter J as a scaling parameter, the effects of the competitions between the reduced crystal fields (D / J), reduced biquadratic exchange interaction parameter (K / J) and the reduced temperature (kT / J) for given values of the probability when the coordination number is q=4, i.e. on a square lattice, are studied in detail.

Medical/Scientific Illustration And Production Of Otological Health Awareness Materials

NASA Technical Reports Server (NTRS)

Hawes, Nicholas E.

2004-01-01

Over the past year, I have worked for my mentor, Beth Cooper, on a large variety of projects. Beth is the Manager of the Acoustical Testing Laboratory, which tests the acoustical emissions of payloads destined for the International Space Station. She is also responsible for educating, and developing new methods of educating, people of all occupational and educational backgrounds in hearing conservation. Beth spends much of her time developing new materials and strategies with which to train people and teach other people to train people in hearing conservation and noise emissions control. I have been helping Beth develop and market these materials by way of graphic design and scientific illustration. Last summer, I spent much of my time creating educational illustrations that visually explained particular concepts in Beth's presentations. Sometimes these illustrations were small "comics" while, at other times, they were an instructional series of illustrations. Since then, Beth and her lab have been developing and updating some materials which will be distributed free to hearing conservation and noise control professionals and others in related fields. I have helped with these projects by designing their packaging. In each instance, it was my responsibility to develop an aesthetically appealing package that would also, through its imagery, describe or summarize the contents of the product. I did this for 3 CD's (Auditory Demonstrations 11, MACSUG, and JeopEARdy) and saw them through their actual production and distribution. In addition to working with Beth, I work with the Imaging Technology Center on various imaging projects. Some of my activities include photo retouching and manipulation for videos and print. This summer, I also had the opportunity to develop a screen saver that would show of some of the photography contained on the soon-to-be-released "Highlights of the GRC Image Archives, vol. 2". I was also able to utilize my medical training to help several of ITC s videographers identify the best histological examples of cancerous cells for incorporation in one of their videos. Over the last part of this summer and then throughout the school year, I will be working with Beth to develop a "pre-packaged" lecture series about the physics of acoustics in the context of hearing conservation. These lectures will be used to teach people of all backgrounds the fundamental concepts involved in acoustical physics so they might be better aware of their own and others auditory health in and out of the work place, and, in the case of payload developers, to design and build more quiet science experiments for the ISS. Even though it may not seem as such, this project is precisely what I am learning to do as a student of the Cleveland Institute of Art's Medical Illustration Department. From my perspective, this project is about taking technical information and translating it into terms that anyone, regardless of background, can understand.

Two-center interference effects in (e, 2e) ionization of H2 and CO2 at large momentum transfer

NASA Astrophysics Data System (ADS)

Yamazaki, Masakazu; Nakajima, Isao; Satoh, Hironori; Watanabe, Noboru; Jones, Darryl; Takahashi, Masahiko

2015-09-01

In recent years, there has been considerable interest in understanding quantum mechanical interference effects in molecular ionization. Since this interference appears as a consequence of coherent electron emission from the different molecular centers, it should depend strongly on the nature of the ionized molecular orbital. Such molecular orbital patterns can be investigated by means of binary (e, 2e) spectroscopy, which is a kinematically-complete electron-impact ionization experiment performed under the high-energy Bethe ridge conditions. In this study, two-center interference effects in the (e, 2e) cross sections of H2 and CO2 at large momentum transfer are demonstrated with a high-statistics experiment, in order to elucidate the relationship between molecular orbital patterns and the interference structure. It is shown that the two-center interference is highly sensitive to the phase, spatial pattern, symmetry of constituent atomic orbital, and chemical bonding nature of the molecular orbital. This work was partially supported by Grant-in-Aids for Scientific Research (S) (No. 20225001) and for Young Scientists (B) (No. 21750005) from the Ministry of Education, Culture, Sports, Science and Technology.

Detecting a heavy neutrino electric dipole moment at the LHC

NASA Astrophysics Data System (ADS)

Sher, Marc; Stevens, Justin R.

2018-02-01

The milliQan Collaboration has proposed to search for millicharged particles by looking for very weakly ionizing tracks in a detector installed in a cavern near the CMS experiment at the LHC. We note that another form of exotica can also yield weakly ionizing tracks. If a heavy neutrino has an electric dipole moment (EDM), then the milliQan experiment may be sensitive to it as well. In particular, writing the general dimension-5 operator for an EDM with a scale of a TeV and a one-loop factor, one finds a potential EDM as high as a few times 10-17 e-cm, and models exist where it is an order of magnitude higher. Redoing the Bethe calculation of ionization energy loss for an EDM, it is found that the milliQan detector is sensitive to EDMs as small as 10-17 e-cm. Using the production cross-section and analyzing the acceptance of the milliQan detector, we find the expected 95% exclusion and 3σ sensitivity over the range of neutrino masses from 5-1000 GeV for integrated luminosities of 300 and 3000 fb-1 at the LHC.

Comparison of the secondary electrons produced by proton and electron beams in water

NASA Astrophysics Data System (ADS)

Kia, Mohammad Reza; Noshad, Houshyar

2016-05-01

The secondary electrons produced in water by electron and proton beams are compared with each other. The total ionization cross section (TICS) for an electron impact in water is obtained by using the binary-encounter-Bethe model. Hence, an empirical equation based on two adjustable fitting parameters is presented to determine the TICS for proton impact in media. In order to calculate the projectile trajectory, a set of stochastic differential equations based on the inelastic collision, elastic scattering, and bremsstrahlung emission are used. In accordance with the projectile trajectory, the depth dose deposition, electron energy loss distribution in a certain depth, and secondary electrons produced in water are calculated. The obtained results for the depth dose deposition and energy loss distribution in certain depth for electron and proton beams with various incident energies in media are in excellent agreement with the reported experimental data. The difference between the profiles for the depth dose deposition and production of secondary electrons for a proton beam can be ignored approximately. But, these profiles for an electron beam are completely different due to the effect of elastic scattering on electron trajectory.

The realization of the dipole (γ, γ) method and its application to determine the absolute optical oscillator strengths of helium.

PubMed

Xu, Long-Quan; Liu, Ya-Wei; Kang, Xu; Ni, Dong-Dong; Yang, Ke; Hiraoka, Nozomu; Tsuei, Ku-Ding; Zhu, Lin-Fan

2015-12-17

The dipole (γ, γ) method, which is the inelastic x-ray scattering operated at a negligibly small momentum transfer, is proposed and realized to determine the absolute optical oscillator strengths of the vanlence-shell excitations of atoms and molecules. Compared with the conventionally used photoabsorption method, this new method is free from the line saturation effect, which can seriously limit the accuracies of the measured photoabsorption cross sections for discrete transitions with narrow natural linewidths. Furthermore, the Bethe-Born conversion factor of the dipole (γ, γ) method varies much more slowly with the excitation energy than does that of the dipole (e, e) method. Absolute optical oscillator strengths for the excitations of 1s(2) → 1 snp(n = 3-7) of atomic helium have been determined using the high-resolution dipole (γ, γ) method, and the excellent agreement of the present measurements with both those measured by the dipole (e, e) method and the previous theoretical calculations indicates that the dipole (γ, γ) method is a powerful tool to measure the absolute optical oscillator strengths of the valence-shell excitations of atoms and molecules.

Comparison of the secondary electrons produced by proton and electron beams in water

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

Kia, Mohammad Reza, E-mail: m-r-kia@aut.ac.ir; Noshad, Houshyar

The secondary electrons produced in water by electron and proton beams are compared with each other. The total ionization cross section (TICS) for an electron impact in water is obtained by using the binary-encounter-Bethe model. Hence, an empirical equation based on two adjustable fitting parameters is presented to determine the TICS for proton impact in media. In order to calculate the projectile trajectory, a set of stochastic differential equations based on the inelastic collision, elastic scattering, and bremsstrahlung emission are used. In accordance with the projectile trajectory, the depth dose deposition, electron energy loss distribution in a certain depth, andmore » secondary electrons produced in water are calculated. The obtained results for the depth dose deposition and energy loss distribution in certain depth for electron and proton beams with various incident energies in media are in excellent agreement with the reported experimental data. The difference between the profiles for the depth dose deposition and production of secondary electrons for a proton beam can be ignored approximately. But, these profiles for an electron beam are completely different due to the effect of elastic scattering on electron trajectory.« less

Suppression of Vascular Growth in Breast Cancer.

DTIC Science & Technology

1995-10-01

Iruela-Arispe CONTRACTING ORGANIZATION: Beth Israel Hospital Boston, Massachusetts 02215 REPORT DATE: October 1995 TYPE OF REPORT: Annual PREPARED...ORGANIZATION NAME(S) AND ADDRESS(ES) Beth Israel Hospital Boston, Massachusetts 02215 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING...tsp/tsp") mice by mating of TSP1 knock-out homozygotes with mice carrying the MMTV c-neu transgene 2. Analysis of the vascular bed, as well as

Mapping Mammary Epithelial Cell Transformation in BRCA1 Mutant Mice

DTIC Science & Technology

2006-07-01

Transformation in BRCA1 Mutant Mice PRINCIPAL INVESTIGATOR: Gerburg M. Wulf CONTRACTING ORGANIZATION: Beth Israel Deaconess Medical...REPORT NUMBER Beth Israel Deaconess Medical Center Boston, MA 02215 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES...and whether it allowed us to analyze the early steps of tumor formation. For this purpose transgenic and conditional knock-out mice (mutant p53 or

Exact solution of the XXX Gaudin model with generic open boundaries

NASA Astrophysics Data System (ADS)

Hao, Kun; Cao, Junpeng; Yang, Tao; Yang, Wen-Li

2015-03-01

The XXX Gaudin model with generic integrable open boundaries specified by the most general non-diagonal reflecting matrices is studied. Besides the inhomogeneous parameters, the associated Gaudin operators have six free parameters which break the U(1) -symmetry. With the help of the off-diagonal Bethe ansatz, we successfully obtained the eigenvalues of these Gaudin operators and the corresponding Bethe ansatz equations.

[Carl Friedrich von Weizsäcker and the Bethe-Weizsäcker cycle].

PubMed

Wiescher, Michael

2014-01-01

The Carbon- or Bethe-Weizsäcker Cycle plays an important role in astrophysics as one of the most important energy sources for a quiescent and explosive hydrogen burning in stars. This paper presents the historical background and the contributions by Carl Friedrich von Weizsäcker and Hans Bethe who provided the first predictions of the cycle. Furthermore, it discussed the experimental verification of the predicted process in the following decades. Also discussed is the extension of the initial Carbon cycle to the CNO multi-cycles and the hot CNO cycles which followed from the detailed experimental studies of the associated nuclear reactions. Finally discussed is the impact of the experimental and theoretical results on our present understanding of hydrogen burning in different stellar environments and on our understanding of the chemical evolution of our universe.

Quasi-soliton scattering in quantum spin chains

NASA Astrophysics Data System (ADS)

Vlijm, R.; Ganahl, M.; Fioretto, D.; Brockmann, M.; Haque, M.; Evertz, H. G.; Caux, J.-S.

2015-12-01

The quantum scattering of magnon bound states in the anisotropic Heisenberg spin chain is shown to display features similar to the scattering of solitons in classical exactly solvable models. Localized colliding Gaussian wave packets of bound magnons are constructed from string solutions of the Bethe equations and subsequently evolved in time, relying on an algebraic Bethe ansatz based framework for the computation of local expectation values in real space-time. The local magnetization profile shows the trajectories of colliding wave packets of bound magnons, which obtain a spatial displacement upon scattering. Analytic predictions on the displacements for various values of anisotropy and string lengths are derived from scattering theory and Bethe ansatz phase shifts, matching time-evolution fits on the displacements. The time-evolved block decimation algorithm allows for the study of scattering displacements from spin-block states, showing similar scattering displacement features.

Quasi-soliton scattering in quantum spin chains

NASA Astrophysics Data System (ADS)

Fioretto, Davide; Vljim, Rogier; Ganahl, Martin; Brockmann, Michael; Haque, Masud; Evertz, Hans-Gerd; Caux, Jean-Sébastien

The quantum scattering of magnon bound states in the anisotropic Heisenberg spin chain is shown to display features similar to the scattering of solitons in classical exactly solvable models. Localized colliding Gaussian wave packets of bound magnons are constructed from string solutions of the Bethe equations and subsequently evolved in time, relying on an algebraic Bethe ansatz based framework for the computation of local expectation values in real space-time. The local magnetization profile shows the trajectories of colliding wave packets of bound magnons, which obtain a spatial displacement upon scattering. Analytic predictions on the displacements for various values of anisotropy and string lengths are derived from scattering theory and Bethe ansatz phase shifts, matching time evolution fits on the displacements. The TEBD algorithm allows for the study of scattering displacements from spin-block states, showing similar displacement scattering features.

Bethe/Gauge correspondence in odd dimension: modular double, non-perturbative corrections and open topological strings

NASA Astrophysics Data System (ADS)

Sciarappa, Antonio

2016-10-01

Bethe/Gauge correspondence as it is usually stated is ill-defined in five dimensions and needs a "non-perturbative" completion; a related problem also appears in three dimensions. It has been suggested that this problem, probably due to incompleteness of Omega background regularization in odd dimension, may be solved if we consider gauge theory on compact S 5 and S 3 geometries. We will develop this idea further by giving a full Bethe/Gauge correspondence dictionary on S 5 and S 3 focussing mainly on the eigenfunctions of (open and closed) relativistic 2-particle Toda chain and its quantized spectral curve: these are most properly written in terms of non-perturbatively completed NS open topological strings. A key ingredient is Faddeev's modular double structure which is naturally implemented by the S 5 and S 3 geometries.

A Demonstration to Assess Effectiveness, Suitability, and Survivability With the Missions and Means Framework

DTIC Science & Technology

2012-12-01

A Demonstration to Assess Effectiveness, Suitability, and Survivability With the Missions and Means Framework by Beth S . Ward, Paul J...Tanenbaum, Keon U. Burley, Paul H. Deitz, Britt E. Bray, Richard S . Sandmeyer, and Jack H. Sheehan ARL-TR-6271 December 2012...Demonstration to Assess Effectiveness, Suitability, and Survivability With the Missions and Means Framework Beth S . Ward, Paul J. Tanenbaum, and Keon U

APOL1 Oligomerization as the Key Mediator of Kidney Disease in African Americans

DTIC Science & Technology

2015-10-01

INVESTIGATOR: Dr. David Friedman CONTRACTING ORGANIZATION: Beth Israel Deaconess Medical Center Boston, MA 02215 REPORT DATE: October 2015 TYPE OF...ORGANIZATION REPORT NUMBER Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215 9. SPONSORING / MONITORING AGENCY NAME(S) AND...different APOL1 genotype with interferon stimulation, then look for oligomer formation in our APOL1 transgenic zebrafish and mouse models, and lastly test

Slavnov and Gaudin-Korepin formulas for models without U (1) symmetry: the XXX chain on the segment

NASA Astrophysics Data System (ADS)

Belliard, S.; Pimenta, R. A.

2016-04-01

We consider the isotropic spin -\\frac{1}{2} Heisenberg chain with the most general integrable boundaries. The scalar product between the on-shell Bethe vector and its off-shell dual, obtained by means of the modified algebraic Bethe ansatz, is given by a modified Slavnov formula. The corresponding Gaudin-Korepin formula, i.e., the square of the norm, is also obtained.

X (3872 ) as a molecular D D\\xAF * state in the Bethe-Salpeter equation approach

NASA Astrophysics Data System (ADS)

Wang, Zhen-Yang; Qi, Jing-Juan; Guo, Xin-Heng; Wang, Chao

2018-01-01

We discuss the possibility that the X (3872 ) can be a D D¯* molecular bound state in the Bethe-Salpeter equation approach in the ladder and instantaneous approximations. We show that the D D¯ * bound state with quantum numbers JP C=1++ exists. We also calculate the decay width of X (3872 )→γ J /ψ channel and compare our result with those from previous calculations.

Numerical Solutions of One Reduced Bethe-Salpeter Equation for the Coulombic Bound States Composed of Virtual Constituents

NASA Astrophysics Data System (ADS)

Chen, Jiao-Kai

2018-04-01

We present one reduction of the Bethe-Salpeter equation for the bound states composed of two off-mass-shell constituents. Both the relativistic effects and the virtuality effects can be considered in the obtained spinless virtuality distribution equation. The eigenvalues of the spinless virtuality distribution equation are perturbatively calculated and the bound states e+e-, μ+μ-, τ+τ-, μ+e-, and τ+e- are discussed.

Crystallographic interpretation of Galois symmetries for magnetic pentagonal ring

NASA Astrophysics Data System (ADS)

Milewski, J.; Lulek, T.; Łabuz, M.

2017-03-01

Galois symmetry of exact Bethe Ansatz eigenstates for the magnetic pentagonal ring within the XXX model are investigated by a comparison with crystallographic constructions of space groups. It follows that the arithmetic symmetry of Bethe parameters for the interior of the Brillouin zone admits crystallographic interpretation, in terms of the periodic square Z2 ×Z2 , that is the two-dimensional crystal lattice with Born-Karman period two in both directions.

The phase diagrams of the ± K model on the Bethe lattice

NASA Astrophysics Data System (ADS)

Albayrak, Erhan

2015-07-01

The biquadratic exchange interaction is randomized in a bimodal form with probabilities (p) and (1 - p) for the cases with K > 0 (attractive case) and K < 0 (repulsive case), respectively, and its effects on the phase diagrams of the spin-1 Blume-Emery-Griffiths model are studied on the Bethe lattice by using the recursion relations. It was found that the critical behaviors of the model change drastically.

Training Aide: Research and Guidance for Effective Training User Guide

DTIC Science & Technology

2013-12-01

Research Product 2014-02 Training Aide: Research and Guidance for Effective Training User Guide Beth Plott Shaun...Effective Training User Guide 5a. CONTRACT OR GRANT NUMBER W91WAW-07-C-0081 5b. PROGRAM ELEMENT NUMBER 611102 6. AUTHOR(S) Beth Plott...Representative and Subject Matter POC: Karin A. Orvis 14. ABSTRACT: This is a user guide for the web-based tool called Training Aide: Research and Guidance

Goldstonic pseudoscalar mesons in Bethe-Salpeter-inspired setting

NASA Astrophysics Data System (ADS)

Lucha, Wolfgang; Schöberl, Franz F.

2018-03-01

For a two-particle bound-state equation closer to its Bethe-Salpeter origins than Salpeter’s equation, with effective interaction kernel deliberately forged such as to ensure, in the limit of zero mass of the bound-state constituents, the vanishing of the arising bound-state mass, we scrutinize the emerging features of the lightest pseudoscalar mesons for their agreement with the behavior predicted by a generalization of the Gell-Mann-Oakes-Renner relation.

Classification of three-state Hamiltonians solvable by the coordinate Bethe ansatz

NASA Astrophysics Data System (ADS)

Crampé, N.; Frappat, L.; Ragoucy, E.

2013-10-01

We classify ‘all’ Hamiltonians with rank 1 symmetry and nearest-neighbour interactions, acting on a periodic three-state spin chain, and solvable through (generalization of) the coordinate Bethe ansatz (CBA). In this way we obtain four multi-parametric extensions of the known 19-vertex Hamiltonians (such as Zamolodchikov-Fateev, Izergin-Korepin and Bariev Hamiltonians). Apart from the 19-vertex Hamiltonians, there exist 17-vertex and 14-vertex Hamiltonians that cannot be viewed as subcases of the 19-vertex ones. In the case of 17-vertex Hamiltonians, we get a generalization of the genus 5 special branch found by Martins, plus three new ones. We also get two 14-vertex Hamiltonians. We solve all these Hamiltonians using CBA, and provide their spectrum, eigenfunctions and Bethe equations. Special attention is given to provide the specifications of our multi-parametric Hamiltonians that give back known Hamiltonians.

Obituary: Elizabeth Katherine Holmes, 1973-2004

NASA Astrophysics Data System (ADS)

Beichman, Charles Arnold

2004-12-01

Elizabeth (Beth) K. Holmes died suddenly in Pasadena on March 23, 2004, from the unexpected effects of a long-standing heart condition. She was 30 years old. At the moment of her passing, she was at her computer comparing her theoretical models on the effects of planets on the distribution of zodiacal dust with some of the first observations from the Spitzer Space Telescope. Born on June 24, 1973, in New York City, Beth was the only child of James and Barbara Holmes, who were respectively, a financial manager and a nurse and social worker. Undeterred by numerous treatments and operations to correct a congenital heart condition, Beth developed an interest in math and physics leading to her graduation from MIT in 1995 with a bachelor's degree in Physics. She entered the University of Florida shortly afterwards to begin her PhD studies under the direction of Stanley Dermott. Beth was particularly interested in the dynamics of interplanetary dust, and initially worked on secular perturbations of the zodiacal cloud: how the planets impose warping of the cloud, and how they can force the center of the cloud to be offset from the Sun. Despite the fact that Beth was primarily a theorist, she was keen to include some observing experience in her PhD education. She recently completed an observing program with Harold Butner at the Steward and Palomar Observatories looking for submillimeter and mid-infrared emission around nearby main-sequence stars - a signpost of planetary formation. The results were published last year in the Astronomical Journal. Beth's PhD thesis work, some results of which were recently published in the Astrophysical Journal, focused on dust originating in the Kuiper belt and how some of this dust is expected to be spatially structured due to resonant interactions with Neptune. This phenomenon may be quite common in other planetary systems, with recent images of Epsilon Eridani perhaps providing a prime example of a Kuiper disk analog. After graduating from Florida in 2002, Beth took up a National Research Council postdoctoral position at the Jet Propulsion Laboratory with Charles Beichman and T. Velusamy with the goal of applying her theoretical knowledge of zodiacal clouds to observations from the Spitzer Space telescope. In advance of the launch of Spitzer, Beth gathered detailed information on over 150 solar type stars and carefully planned a Spitzer observing program to detect faint zodiacal signals. While waiting through numerous launch delays, she prepared models of zodiacal clouds influenced by the presence of planets to be ready when Spitzer images of stars like Vega, Upsilon Andromedae, and Fomalhaut became available. These models were presented as talks and posters at a number of conferences. Her models were a critical part of the Early Release Observations of Fomalhaut and the subsequent Spitzer paper on the possibility that a Jovian-mass planet located approximately 40 AU from the star was responsible for the structures seen in the Fomalhaut disk. The Fomalhaut paper in the special Spitzer edition of the Astrophysical Journal is dedicated to Beth's memory. Beth was an enthusiastic and cheerful colleague who made friends everywhere she worked. In addition to developing friendships and collaborations at JPL, she became a valued member of the Spitzer/MIPS instrument team at the University of Arizona. She was active on the Committee on the Status of Women in Astronomy of the American Astronomical Society, publishing an article on "The Postdoc Perspective on the Women in Astronomy II Conference" in the January 2004 issue of STATUS, the CSWA magazine, and serving as an associate editor of that magazine. She was an inspiring role model for young women in science, befriending and mentoring a number of Caltech women undergraduates, as well as making numerous appearances in K-12 classrooms for science outreach. She pursued her love of plants (cactus in particular), cats and fish, spending her spare time lovingly tending her small garden. Her friends and colleagues will remember Beth for her scientific contributions, but also for her courage as we realize that she worked beside us completely unshadowed by the heart condition that would take her in so sudden and untimely a manner. We take solace in the knowledge that at the moment of her passing, she was pursuing her passion for astronomy, working among colleagues who valued her work and her friendship, that she had a supportive and loving family with parents on the East Coast and close relatives on the West Coast, and that in her fiancé, Todd Rope, she had found a kindred spirit.

Loop expansion around the Bethe approximation through the M-layer construction

NASA Astrophysics Data System (ADS)

Altieri, Ada; Chiara Angelini, Maria; Lucibello, Carlo; Parisi, Giorgio; Ricci-Tersenghi, Federico; Rizzo, Tommaso

2017-11-01

For every physical model defined on a generic graph or factor graph, the Bethe M-layer construction allows building a different model for which the Bethe approximation is exact in the large M limit, and coincides with the original model for M=1 . The 1/M perturbative series is then expressed by a diagrammatic loop expansion in terms of so-called fat diagrams. Our motivation is to study some important second-order phase transitions that do exist on the Bethe lattice, but are either qualitatively different or absent in the corresponding fully connected case. In this case, the standard approach based on a perturbative expansion around the naive mean field theory (essentially a fully connected model) fails. On physical grounds, we expect that when the construction is applied to a lattice in finite dimension there is a small region of the external parameters, close to the Bethe critical point, where strong deviations from mean-field behavior will be observed. In this region, the 1/M expansion for the corrections diverges, and can be the starting point for determining the correct non-mean-field critical exponents using renormalization group arguments. In the end, we will show that the critical series for the generic observable can be expressed as a sum of Feynman diagrams with the same numerical prefactors of field theories. However, the contribution of a given diagram is not evaluated by associating Gaussian propagators to its lines, as in field theories: one has to consider the graph as a portion of the original lattice, replacing the internal lines with appropriate one-dimensional chains, and attaching to the internal points the appropriate number of infinite-size Bethe trees to restore the correct local connectivity of the original model. The actual contribution of each (fat) diagram is the so-called line-connected observable, which also includes contributions from sub-diagrams with appropriate prefactors. In order to compute the corrections near to the critical point, Feynman diagrams (with their symmetry factors) can be read directly from the appropriate field-theoretical literature; the computation of momentum integrals is also quite similar; the extra work consists of computing the line-connected observable of the associated fat diagram in the limit of all lines becoming infinitely long.

American Armed Forces in Mexico? Not Any Time Soon

DTIC Science & Technology

2011-10-28

1848. U.S. declared war, invaded/operated in Mexico for 18 months, and occupied Mexico City. The Hidalgo treaty was signed in February 1848 ending...Mexico." January 2011. http://www.hrw.org/sites/default/files/related_material/mexico_2.pdf (accessed October 23, 2011): 1-2. 44. Mary Beth...Corporation, 2009. Sheridan, Mary Beth. "Clinton vows support for Mexico in drug war, urges progress on rights." The Washington Post, January 24, 2011

Equation for the Nakanishi Weight Function Using the Inverse Stieltjes Transform

NASA Astrophysics Data System (ADS)

Karmanov, V. A.; Carbonell, J.; Frederico, T.

2018-05-01

The bound state Bethe-Salpeter amplitude was expressed by Nakanishi in terms of a smooth weight function g. By using the generalized Stieltjes transform, we derive an integral equation for the Nakanishi function g for a bound state case. It has the standard form g= \\hat{V} g, where \\hat{V} is a two-dimensional integral operator. The prescription for obtaining the kernel V starting with the kernel K of the Bethe-Salpeter equation is given.

GW and Bethe-Salpeter study of small water clusters

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

Blase, Xavier, E-mail: xavier.blase@neel.cnrs.fr; Boulanger, Paul; Bruneval, Fabien

We study within the GW and Bethe-Salpeter many-body perturbation theories the electronic and optical properties of small (H{sub 2}O){sub n} water clusters (n = 1-6). Comparison with high-level CCSD(T) Coupled-Cluster at the Single Double (Triple) levels and ADC(3) Green’s function third order algebraic diagrammatic construction calculations indicates that the standard non-self-consistent G{sub 0}W{sub 0}@PBE or G{sub 0}W{sub 0}@PBE0 approaches significantly underestimate the ionization energy by about 1.1 eV and 0.5 eV, respectively. Consequently, the related Bethe-Salpeter lowest optical excitations are found to be located much too low in energy when building transitions from a non-self-consistent G{sub 0}W{sub 0} description ofmore » the quasiparticle spectrum. Simple self-consistent schemes, with update of the eigenvalues only, are shown to provide a weak dependence on the Kohn-Sham starting point and a much better agreement with reference calculations. The present findings rationalize the theory to experiment possible discrepancies observed in previous G{sub 0}W{sub 0} and Bethe-Salpeter studies of bulk water. The increase of the optical gap with increasing cluster size is consistent with the evolution from gas to dense ice or water phases and results from an enhanced screening of the electron-hole interaction.« less

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

Cirilo Antonio, N.; Manojlovic, N.; Departamento de Matematica, FCT, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro

sl{sub 2} Gaudin model with jordanian twist is studied. This system can be obtained as the semiclassical limit of the XXX spin chain deformed by the jordanian twist. The appropriate creation operators that yield the Bethe states of the Gaudin model and consequently its spectrum are defined. Their commutation relations with the generators of the corresponding loop algebra as well as with the generating function of integrals of motion are given. The inner products and norms of Bethe states and the relation to the solutions of the Knizhnik-Zamolodchikov equations are discussed.

Slavnov and Gaudin-Korepin Formulas for Models without U(1) Symmetry: the Twisted XXX Chain

NASA Astrophysics Data System (ADS)

Belliard, Samuel; Pimenta, Rodrigo A.

2015-12-01

We consider the XXX spin-1/2 Heisenberg chain on the circle with an arbitrary twist. We characterize its spectral problem using the modified algebraic Bethe anstaz and study the scalar product between the Bethe vector and its dual. We obtain modified Slavnov and Gaudin-Korepin formulas for the model. Thus we provide a first example of such formulas for quantum integrable models without U(1) symmetry characterized by an inhomogenous Baxter T-Q equation.

Bethe-Salpeter Eigenvalue Solver Package (BSEPACK) v0.1

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

SHAO, MEIYEU; YANG, CHAO

2017-04-25

The BSEPACK contains a set of subroutines for solving the Bethe-Salpeter Eigenvalue (BSE) problem. This type of problem arises in this study of optical excitation of nanoscale materials. The BSE problem is a structured non-Hermitian eigenvalue problem. The BSEPACK software can be used to compute all or subset of eigenpairs of a BSE Hamiltonian. It can also be used to compute the optical absorption spectrum without computing BSE eigenvalues and eigenvectors explicitly. The package makes use of the ScaLAPACK, LAPACK and BLAS.

Quantum dot in interacting environments

NASA Astrophysics Data System (ADS)

Rylands, Colin; Andrei, Natan

2018-04-01

A quantum impurity attached to an interacting quantum wire gives rise to an array of new phenomena. Using the Bethe Ansatz we solve exactly models describing two geometries of a quantum dot coupled to an interacting quantum wire: a quantum dot that is (i) side coupled and (ii) embedded in a Luttinger liquid. We find the eigenstates and determine the spectrum through the Bethe Ansatz equations. Using this we derive exact expressions for the ground-state dot occupation. The thermodynamics are then studied using the thermodynamics Bethe Ansatz equations. It is shown that at low energies the dot becomes fully hybridized and acts as a backscattering impurity or tunnel junction depending on the geometry and furthermore that the two geometries are related by changing the sign of the interactions. Although remaining strongly coupled for all values of the interaction in the wire, there exists competition between the tunneling and backscattering leading to a suppression or enhancement of the dot occupation depending on the sign of the bulk interactions.

Range of validity for perturbative treatments of relativistic sum rules

NASA Astrophysics Data System (ADS)

Cohen, Scott M.

2003-10-01

The range of validity of perturbative calculations of relativistic sum rules is investigated by calculating the second-order relativistic corrections to the Bethe sum rule and its small momentum limit, the Thomas-Reiche-Kuhn (TRK) sum rule. For the TRK sum rule and atomic systems, the second-order correction is found to be less than 0.5% up to about Z=70. The total relativistic corrections should then be accurate at least through this range of Z, and probably beyond this range if the second-order terms are included. For Rn (Z=86), however, the second-order corrections are nearly 1%. The total corrections to the Bethe sum rule are largest at small momentum, never being significantly larger than the corresponding corrections to the TRK sum rule. The first-order corrections to the Bethe sum rule also give better than 0.5% accuracy for Z<70, and inclusion of the second-order corrections should extend this range, as well.

Solutions of the Bethe ansatz equations for XXX antiferromagnet of arbitrary spin in the case of a finite number of sites

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

Avdeev, L.V.; Doerfel, B.D.

1987-11-01

The exactly integrable isotropic Heisenberg chain of N spins s is studied, and numerical solutions to the Bethe ansatz equations corresponding to the antiferromagnetic vacuum (for sN less than or equal to 128) and the simplest excitations have been obtained. For s = 1, a complete set of states for N = 6 is given, and the vacuum solution for finite N is estimated analytically. The deviations from the string picture at large N are discussed.

Algebraic Bethe ansatz for U(1) invariant integrable models: Compact and non-compact applications

NASA Astrophysics Data System (ADS)

Martins, M. J.; Melo, C. S.

2009-10-01

We apply the algebraic Bethe ansatz developed in our previous paper [C.S. Melo, M.J. Martins, Nucl. Phys. B 806 (2009) 567] to three different families of U(1) integrable vertex models with arbitrary N bond states. These statistical mechanics systems are based on the higher spin representations of the quantum group U[SU(2)] for both generic and non-generic values of q as well as on the non-compact discrete representation of the SL(2,R) algebra. We present for all these models the explicit expressions for both the on-shell and the off-shell properties associated to the respective transfer matrices eigenvalue problems. The amplitudes governing the vectors not parallel to the Bethe states are shown to factorize in terms of elementary building blocks functions. The results for the non-compact SL(2,R) model are argued to be derived from those obtained for the compact systems by taking suitable N→∞ limits. This permits us to study the properties of the non-compact SL(2,R) model starting from systems with finite degrees of freedom.

Introduction to the thermodynamic Bethe ansatz

NASA Astrophysics Data System (ADS)

van Tongeren, Stijn J.

2016-08-01

We give a pedagogical introduction to the thermodynamic Bethe ansatz, a method that allows us to describe the thermodynamics of integrable models whose spectrum is found via the (asymptotic) Bethe ansatz. We set the stage by deriving the Fermi-Dirac distribution and associated free energy of free electrons, and then in a similar though technically more complicated fashion treat the thermodynamics of integrable models, focusing first on the one-dimensional Bose gas with delta function interaction as a clean pedagogical example, secondly the XXX spin chain as an elementary (lattice) model with prototypical complicating features in the form of bound states, and finally the {SU}(2) chiral Gross-Neveu model as a field theory example. Throughout this discussion we emphasize the central role of particle and hole densities, whose relations determine the model under consideration. We then discuss tricks that allow us to use the same methods to describe the exact spectra of integrable field theories on a circle, in particular the chiral Gross-Neveu model. We moreover discuss the simplification of TBA equations to Y systems, including the transition back to integral equations given sufficient analyticity data, in simple examples.

Quantizing the Toda lattice

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

Siddharthan, R.; Shastry, B.S.

In this work we study the quantum Toda lattice, developing the asymptotic Bethe ansatz method first used by Sutherland. Despite its known limitations we find, on comparing with Gutzwiller{close_quote}s exact method, that it works well in this particular problem and in fact becomes exact as {h_bar} grows large. We calculate ground state and excitation energies for finite-sized lattices, identify excitations as phonons and solitons on the basis of their quantum numbers, and find their dispersions. These are similar to the classical dispersions for small {h_bar}, and remain similar all the way up to {h_bar}=1, but then deviate substantially as wemore » go farther into the quantum regime. On comparing the sound velocities for various {h_bar} obtained thus with that predicted by conformal theory we conclude that the Bethe ansatz gives the energies per particle accurate to O(1/N{sup 2}). On that assumption we can find correlation functions. Thus the Bethe ansatz method can be used to yield much more than the thermodynamic properties which previous authors have calculated. {copyright} {ital 1997} {ital The American Physical Society}« less

On integrable boundaries in the 2 dimensional O(N) σ-models

NASA Astrophysics Data System (ADS)

Aniceto, Inês; Bajnok, Zoltán; Gombor, Tamás; Kim, Minkyoo; Palla, László

2017-09-01

We make an attempt to map the integrable boundary conditions for 2 dimensional non-linear O(N) σ-models. We do it at various levels: classically, by demanding the existence of infinitely many conserved local charges and also by constructing the double row transfer matrix from the Lax connection, which leads to the spectral curve formulation of the problem; at the quantum level, we describe the solutions of the boundary Yang-Baxter equation and derive the Bethe-Yang equations. We then show how to connect the thermodynamic limit of the boundary Bethe-Yang equations to the spectral curve.

A structure preserving Lanczos algorithm for computing the optical absorption spectrum

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

Shao, Meiyue; Jornada, Felipe H. da; Lin, Lin

2016-11-16

We present a new structure preserving Lanczos algorithm for approximating the optical absorption spectrum in the context of solving full Bethe-Salpeter equation without Tamm-Dancoff approximation. The new algorithm is based on a structure preserving Lanczos procedure, which exploits the special block structure of Bethe-Salpeter Hamiltonian matrices. A recently developed technique of generalized averaged Gauss quadrature is incorporated to accelerate the convergence. We also establish the connection between our structure preserving Lanczos procedure with several existing Lanczos procedures developed in different contexts. Numerical examples are presented to demonstrate the effectiveness of our Lanczos algorithm.

Phase diagram of the isotropic spin-(3)/(2) model on the z=3 Bethe lattice

NASA Astrophysics Data System (ADS)

Depenbrock, Stefan; Pollmann, Frank

2013-07-01

We study an SU(2) symmetric spin-3/2 model on the z=3 Bethe lattice using the infinite time evolving block decimation (iTEBD) method. This model is shown to exhibit a rich phase diagram. We compute several order parameters which allow us to identify a ferromagnetic, a ferrimagnetic, an antiferromagnetic, as well as a dimerized phase. We calculate the entanglement spectra from which we conclude the existence of a symmetry protected topological phase that is characterized by S=1/2 edge spins. Details of the iTEBD algorithm used for the simulations are included.

Elementary functions in thermodynamic Bethe ansatz

NASA Astrophysics Data System (ADS)

Suzuki, J.

2015-05-01

Some years ago, Fendley found an explicit solution to the thermodynamic Bethe ansatz (TBA) equation for an N=2 supersymmetric theory in 2D with a specific F-term. Motivated by this, we seek explicit solutions for other super-potential cases utilizing the idea from the ODE/IM correspondence. We find that the TBA equations, corresponding to a wider class of super-potentials, admit solutions in terms of elementary functions such as modified Bessel functions and confluent hyper-geometric series. Based on talks given at ‘Infinite Analysis 2014’ (Tokyo, 2014) and at ‘Integrable lattice models and quantum field theories’ (Bad Honnef, 2014).

AdS/CFT duality at strong coupling

NASA Astrophysics Data System (ADS)

Beccaria, M.; Ortix, C.

2007-08-01

We study the strong-coupling limit of the AdS/CFT correspondence in the framework of a recently proposed fermionic formulation of the Bethe ansatz equations governing the gauge theory anomalous dimensions. We give examples of states that do not follow the Gubser-Klebanov-Polyakov law at a large ’t Hooft coupling λ, in contrast to recent results on the quantum string Bethe equations that are valid in that regime. This result indicates that the fermionic construction cannot be trusted at large λ, although it remains an efficient tool for computing the weak-coupling expansion of anomalous dimensions.

Obituary: Beth Brown (1969-2008)

NASA Astrophysics Data System (ADS)

Bregman, Joel

2011-12-01

The astronomical community lost one of its most buoyant and caring individuals when Beth Brown died, unexpectedly, at the age of 39 from a pulmonary embolism. Beth Brown was born in Roanoke, Virginia where she developed a deep interest in astronomy, science, and science fiction (Star Trek). After graduating as the valedictorian of William Fleming High School's Class of 1987, she attended Howard University, where she graduated summa cum laude in 1991 with a bachelor's degree in astrophysics. Following a year in the graduate physics program at Howard, she entered the graduate program in the Department of Astronomy at the University of Michigan, the first African-American woman in the program. She received her PhD in 1998, working with X-ray observations of elliptical galaxies from the Röntgen Satellite (ROSAT; Joel Bregman was her advisor). She compiled and analyzed the first large complete sample of such galaxies with ROSAT and her papers in this area made an impact in the field. Following her PhD, Beth Brown held a National Academy of Science & National Research Council Postdoctoral Research Fellowship at NASA's Goddard Space Flight Center. Subsequently, she became a civil servant at the National Space Science Data Center at GSFC, where she was involved in data archival activities as well as education and outreach, a continuing passion in her life. In 2006, Brown became an Astrophysics Fellow at GSFC, during which time she worked as a visiting Assistant Professor at Howard University, where she taught and worked with students and faculty to improve the teaching observatory. At the time of her death, she was eagerly looking forward to a new position at GSFC as the Assistant Director for Science Communications and Higher Education. Beth Brown was a joyous individual who loved to work with people, especially in educating them about our remarkable field. Her warmth and openness was a great aid in making accessible explanations of otherwise daunting astrophysical phenomena. She was involved in outreach and education at many levels and throughout her career. She would give planetarium shows, popular science talks for the public, and would speak to local and national news agencies, where she would explain recent NASA science findings. Among other contributions to higher education, she created a course, "Naked Eye Astronomy" at the University of Michigan, which remains the most popular course that the department offers. She was an active member of the National Society of Black Physicists (NSBP), where she was a frequent speaker as well as a mentor to students. Beth Brown was an inspiration to women and minorities in encouraging them to pursue careers in astronomy and physics. One could not find a finer roll model. She will be missed but not forgotten.

SU-C-BRC-06: OpenCL-Based Cross-Platform Monte Carlo Simulation Package for Carbon Ion Therapy

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

Qin, N; Tian, Z; Pompos, A

2016-06-15

Purpose: Monte Carlo (MC) simulation is considered to be the most accurate method for calculation of absorbed dose and fundamental physical quantities related to biological effects in carbon ion therapy. Its long computation time impedes clinical and research applications. We have developed an MC package, goCMC, on parallel processing platforms, aiming at achieving accurate and efficient simulations for carbon therapy. Methods: goCMC was developed under OpenCL framework. It supported transport simulation in voxelized geometry with kinetic energy up to 450 MeV/u. Class II condensed history algorithm was employed for charged particle transport with stopping power computed via Bethe-Bloch equation. Secondarymore » electrons were not transported with their energy locally deposited. Energy straggling and multiple scattering were modeled. Production of secondary charged particles from nuclear interactions was implemented based on cross section and yield data from Geant4. They were transported via the condensed history scheme. goCMC supported scoring various quantities of interest e.g. physical dose, particle fluence, spectrum, linear energy transfer, and positron emitting nuclei. Results: goCMC has been benchmarked against Geant4 with different phantoms and beam energies. For 100 MeV/u, 250 MeV/u and 400 MeV/u beams impinging to a water phantom, range difference was 0.03 mm, 0.20 mm and 0.53 mm, and mean dose difference was 0.47%, 0.72% and 0.79%, respectively. goCMC can run on various computing devices. Depending on the beam energy and voxel size, it took 20∼100 seconds to simulate 10{sup 7} carbons on an AMD Radeon GPU card. The corresponding CPU time for Geant4 with the same setup was 60∼100 hours. Conclusion: We have developed an OpenCL-based cross-platform carbon MC simulation package, goCMC. Its accuracy, efficiency and portability make goCMC attractive for research and clinical applications in carbon therapy.« less

Modified n-level, n - 1-mode Tavis-Cummings model and algebraic Bethe ansatz

NASA Astrophysics Data System (ADS)

Skrypnyk, T.

2018-01-01

Using the quantum group technique we construct a one-parametric family of integrable modifications of the n-level, n-1 mode Tavis-Cummings Hamiltonian possessing an additional Stark-type term. We show that in the ‘quasiclassical’ limit the constructed Hamiltonian transforms into the integrable Hamiltonian of the quantum n-level, n-1 mode Tavis-Cummings model with the equal interaction strengths considered in Skrypnyk (2008 J. Phys. A: Math. Theor. 41 475202, 2009 J. Math. Phys. 50 103523). We diagonalize the constructed ‘modified’ Tavis-Cummings Hamiltonian and its second order integrals of motion using the nested Bethe ansatz.

Towards a model of pion generalized parton distributions from Dyson-Schwinger equations

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

Moutarde, H.

2015-04-10

We compute the pion quark Generalized Parton Distribution H{sup q} and Double Distributions F{sup q} and G{sup q} in a coupled Bethe-Salpeter and Dyson-Schwinger approach. We use simple algebraic expressions inspired by the numerical resolution of Dyson-Schwinger and Bethe-Salpeter equations. We explicitly check the support and polynomiality properties, and the behavior under charge conjugation or time invariance of our model. We derive analytic expressions for the pion Double Distributions and Generalized Parton Distribution at vanishing pion momentum transfer at a low scale. Our model compares very well to experimental pion form factor or parton distribution function data.

Study of Y and Lu iron garnets using Bethe-Peierls-Weiss method

NASA Astrophysics Data System (ADS)

Goveas, Neena; Mukhopadhyay, G.; Mukhopadhyay, P.

1994-11-01

We study here the magnetic properties of Y- and Lu- Iron Garnets using the Bethe- Peierls-Weiss method modified to suit complex systems like these Garnets. We consider these Garnets as described by Heisenberg Hamiltonian with two sublattices (a,d) and determine the exchange interaction parameters Jad, Jaa and Jdd by matching the exerimental susceptibility curves. We find Jaa and Jdd to be much smaller than those determined by Néel theory, and consistent with those obtained by the study of spin wave spectra; the spin wave dispersion relation constant obtained using these parameters gives good agreement with the experimental values.

Density matrix renormalization group simulations of SU(N ) Heisenberg chains using standard Young tableaus: Fundamental representation and comparison with a finite-size Bethe ansatz

NASA Astrophysics Data System (ADS)

Nataf, Pierre; Mila, Frédéric

2018-04-01

We develop an efficient method to perform density matrix renormalization group simulations of the SU(N ) Heisenberg chain with open boundary conditions taking full advantage of the SU(N ) symmetry of the problem. This method is an extension of the method previously developed for exact diagonalizations and relies on a systematic use of the basis of standard Young tableaux. Concentrating on the model with the fundamental representation at each site (i.e., one particle per site in the fermionic formulation), we have benchmarked our results for the ground-state energy up to N =8 and up to 420 sites by comparing them with Bethe ansatz results on open chains, for which we have derived and solved the Bethe ansatz equations. The agreement for the ground-state energy is excellent for SU(3) (12 digits). It decreases with N , but it is still satisfactory for N =8 (six digits). Central charges c are also extracted from the entanglement entropy using the Calabrese-Cardy formula and agree with the theoretical values expected from the SU (N) 1 Wess-Zumino-Witten conformal field theories.

Bukhvostov-Lipatov model and quantum-classical duality

NASA Astrophysics Data System (ADS)

Bazhanov, Vladimir V.; Lukyanov, Sergei L.; Runov, Boris A.

2018-02-01

The Bukhvostov-Lipatov model is an exactly soluble model of two interacting Dirac fermions in 1 + 1 dimensions. The model describes weakly interacting instantons and anti-instantons in the O (3) non-linear sigma model. In our previous work [arxiv:arXiv:1607.04839] we have proposed an exact formula for the vacuum energy of the Bukhvostov-Lipatov model in terms of special solutions of the classical sinh-Gordon equation, which can be viewed as an example of a remarkable duality between integrable quantum field theories and integrable classical field theories in two dimensions. Here we present a complete derivation of this duality based on the classical inverse scattering transform method, traditional Bethe ansatz techniques and analytic theory of ordinary differential equations. In particular, we show that the Bethe ansatz equations defining the vacuum state of the quantum theory also define connection coefficients of an auxiliary linear problem for the classical sinh-Gordon equation. Moreover, we also present details of the derivation of the non-linear integral equations determining the vacuum energy and other spectral characteristics of the model in the case when the vacuum state is filled by 2-string solutions of the Bethe ansatz equations.

Simulating the Generalized Gibbs Ensemble (GGE): A Hilbert space Monte Carlo approach

NASA Astrophysics Data System (ADS)

Alba, Vincenzo

By combining classical Monte Carlo and Bethe ansatz techniques we devise a numerical method to construct the Truncated Generalized Gibbs Ensemble (TGGE) for the spin-1/2 isotropic Heisenberg (XXX) chain. The key idea is to sample the Hilbert space of the model with the appropriate GGE probability measure. The method can be extended to other integrable systems, such as the Lieb-Liniger model. We benchmark the approach focusing on GGE expectation values of several local observables. As finite-size effects decay exponentially with system size, moderately large chains are sufficient to extract thermodynamic quantities. The Monte Carlo results are in agreement with both the Thermodynamic Bethe Ansatz (TBA) and the Quantum Transfer Matrix approach (QTM). Remarkably, it is possible to extract in a simple way the steady-state Bethe-Gaudin-Takahashi (BGT) roots distributions, which encode complete information about the GGE expectation values in the thermodynamic limit. Finally, it is straightforward to simulate extensions of the GGE, in which, besides the local integral of motion (local charges), one includes arbitrary functions of the BGT roots. As an example, we include in the GGE the first non-trivial quasi-local integral of motion.

Rigged String Configurations, Bethe Ansatz Qubits, and Conservation of Parity

NASA Astrophysics Data System (ADS)

Lulek, T.

Bethe Ansatz solutions for the Heisenberg Hamiltonian of a one - dimensional magnetic ring of N nodes, each with the spin 1/2, within the XXX model, have been presented as some composite systems, in a spirit of quantum information theory. The constituents are single - node spin states, which organize into strings of various length, and "seas of holes". The former are responsible for dynamics, whereas the latter determine the range of riggings for strings. Another aim was to demonstrate a unification of Bethe Ansatz eigenstates by means of Galois symmetries of finite field extensions. The key observation is that the original eigenproblem is expressible in integers, and thus, for a finite fixed N, the splitting field of the characteristic polynom of the Heisenberg Hamiltonian is also finite. The Galois group of the latter field permutes, by definition, roots of this polynom, which implies permutation of eigenstates. General considerations are demonstrated on the example of heptagon (N = 7), which admits an implementation of a collection of arithmetic qubits, and also demonstrates a special case of degeneration of the spectrum of the Hamiltonian, resulting from conservation of parity, within the realm of rigged string configurations.

Exact quantum numbers of collapsed and non-collapsed two-string solutions in the spin-1/2 Heisenberg spin chain

NASA Astrophysics Data System (ADS)

Deguchi, Tetsuo; Ranjan Giri, Pulak

2016-04-01

Every solution of the Bethe-ansatz equations (BAEs) is characterized by a set of quantum numbers, by which we can evaluate it numerically. However, no general rule is known how to give quantum numbers for the physical solutions of BAE. For the spin-1/2 XXX chain we rigorously derive all the quantum numbers for the complete set of the Bethe-ansatz eigenvectors in the two down-spin sector with any chain length N. Here we obtain them both for real and complex solutions. We also show that all the solutions associated with them are distinct. Consequently, we prove the completeness of the Bethe ansatz and give an exact expression for the number of real solutions which correspond to collapsed bound-state solutions (i.e., two-string solutions) in the sector: 2[(N-1)/2-(N/π ){{tan}}-1(\\sqrt{N-1})] in terms of Gauss’ symbol. Moreover, we prove in the sector the scheme conjectured by Takahashi for solving BAE systematically. We also suggest that by applying the present method we can derive the quantum numbers for the spin-1/2 XXZ chain.

Color-suppression of non-planar diagrams in bosonic bound states

NASA Astrophysics Data System (ADS)

Alvarenga Nogueira, J. H.; Ji, Chueng-Ryong; Ydrefors, E.; Frederico, T.

2018-02-01

We study the suppression of non-planar diagrams in a scalar QCD model of a meson system in 3 + 1 space-time dimensions due to the inclusion of the color degrees of freedom. As a prototype of the color-singlet meson, we consider a flavor-nonsinglet system consisting of a scalar-quark and a scalar-antiquark with equal masses exchanging a scalar-gluon of a different mass, which is investigated within the framework of the homogeneous Bethe-Salpeter equation. The equation is solved by using the Nakanishi representation for the manifestly covariant bound-state amplitude and its light-front projection. The resulting non-singular integral equation is solved numerically. The damping of the impact of the cross-ladder kernel on the binding energies are studied in detail. The color-suppression of the cross-ladder effects on the light-front wave function and the elastic electromagnetic form factor are also discussed. As our results show, the suppression appears significantly large for Nc = 3, which supports the use of rainbow-ladder truncations in practical non-perturbative calculations within QCD.

Bethe Ansatz for the Weakly Asymmetric Simple Exclusion Process and Phase Transition in the Current Distribution

NASA Astrophysics Data System (ADS)

Simon, Damien

2011-03-01

The probability distribution of the current in the asymmetric simple exclusion process is expected to undergo a phase transition in the regime of weak asymmetry of the jumping rates. This transition was first predicted by Bodineau and Derrida using a linear stability analysis of the hydrodynamical limit of the process and further arguments have been given by Mallick and Prolhac. However it has been impossible so far to study what happens after the transition. The present paper presents an analysis of the large deviation function of the current on both sides of the transition from a Bethe Ansatz approach of the weak asymmetry regime of the exclusion process.

Fast analytic solver of rational Bethe equations

NASA Astrophysics Data System (ADS)

Marboe, C.; Volin, D.

2017-05-01

In this note we propose an approach for a fast analytic determination of all possible sets of Bethe roots corresponding to eigenstates of rational {GL}({N}\\vert {M}) integrable spin chains of given not too large length, in terms of Baxter Q-functions. We observe that all exceptional solutions, if any, are automatically correctly accounted. The key intuition behind the approach is that the equations on the Q-functions are determined solely by the Young diagram, and not by the choice of the rank of the {GL} symmetry. Hence we can choose arbitrary {N} and {M} that accommodate the desired representation. Then we consider all distinguished Q-functions at once, not only those following a certain Kac-Dynkin path.

Quantization of the Kadomtsev-Petviashvili equation

NASA Astrophysics Data System (ADS)

Kozlowski, K.; Sklyanin, E. K.; Torrielli, A.

2017-08-01

We propose a quantization of the Kadomtsev-Petviashvili equation on a cylinder equivalent to an infinite system of nonrelativistic one-dimensional bosons with the masses m = 1, 2,.... The Hamiltonian is Galilei-invariant and includes the split and merge terms Ψ _{{m_1}}^\\dag Ψ _{{m_2}}^\\dag {Ψ _{{m_1} + {m_2}}} and Ψ _{{m_1} + {m_2}}^\\dag {Ψ _{{m_1}}}{Ψ _{{m_2}}} for all combinations of particles with masses m 1, m 2, and m 1 + m 2 for a special choice of coupling constants. We construct the Bethe eigenfunctions for the model and verify the consistency of the coordinate Bethe ansatz and hence the quantum integrability of the model up to the mass M=8 sector.

Complete spectrum of long operators in Script N = 4 SYM at one loop

NASA Astrophysics Data System (ADS)

Beisert, Niklas; Kazakov, Vladimir A.; Sakai, Kazuhiro; Zarembo, Konstantin

2005-07-01

We construct the complete spectral curve for an arbitrary local operator, including fermions and covariant derivatives, of one-loop Script N = 4 gauge theory in the thermodynamic limit. This curve perfectly reproduces the Frolov-Tseytlin limit of the full spectral curve of classical strings on AdS5 × S5 derived in [64]. To complete the comparison we introduce stacks, novel bound states of roots of different flavors which arise in the thermodynamic limit of the corresponding Bethe ansatz equations. We furthermore show the equivalence of various types of Bethe equations for the underlying fraktur sfraktur u(2,2|4) superalgebra, in particular of the type ``Beauty'' and ``Beast''.

New construction of eigenstates and separation of variables for SU( N) quantum spin chains

NASA Astrophysics Data System (ADS)

Gromov, Nikolay; Levkovich-Maslyuk, Fedor; Sizov, Grigory

2017-09-01

We conjecture a new way to construct eigenstates of integrable XXX quantum spin chains with SU( N) symmetry. The states are built by repeatedly acting on the vacuum with a single operator B good( u) evaluated at the Bethe roots. Our proposal serves as a compact alternative to the usual nested algebraic Bethe ansatz. Furthermore, the roots of this operator give the separated variables of the model, explicitly generalizing Sklyanin's approach to the SU( N) case. We present many tests of the conjecture and prove it in several special cases. We focus on rational spin chains with fundamental representation at each site, but expect many of the results to be valid more generally.

Excited state correlations of the finite Heisenberg chain

NASA Astrophysics Data System (ADS)

Pozsgay, Balázs

2017-02-01

We consider short range correlations in excited states of the finite XXZ and XXX Heisenberg spin chains. We conjecture that the known results for the factorized ground state correlations can be applied to the excited states too, if the so-called physical part of the construction is changed appropriately. For the ground state we derive simple algebraic expressions for the physical part; the formulas only use the ground state Bethe roots as an input. We conjecture that the same formulas can be applied to the excited states as well, if the exact Bethe roots of the excited states are used instead. In the XXZ chain the results are expected to be valid for all states (except certain singular cases where regularization is needed), whereas in the XXX case they only apply to singlet states or group invariant operators. Our conjectures are tested against numerical data from exact diagonalization and coordinate Bethe Ansatz calculations, and perfect agreement is found in all cases. In the XXX case we also derive a new result for the nearest-neighbour correlator < σ 1zσ 2z> , which is valid for non-singlet states as well. Our results build a bridge between the known theory of factorized correlations, and the recently conjectured TBA-like description for the building blocks of the construction.

One-loop topological expansion for spin glasses in the large connectivity limit

NASA Astrophysics Data System (ADS)

Chiara Angelini, Maria; Parisi, Giorgio; Ricci-Tersenghi, Federico

2018-01-01

We apply for the first time a new one-loop topological expansion around the Bethe solution to the spin-glass model with a field in the high connectivity limit, following the methodological scheme proposed in a recent work. The results are completely equivalent to the well-known ones, found by standard field-theoretical expansion around the fully connected model (Bray and Roberts 1980, and following works). However this method has the advantage that the starting point is the original Hamiltonian of the model, with no need to define an associated field theory, nor to know the initial values of the couplings, and the computations have a clear and simple physical meaning. Moreover this new method can also be applied in the case of zero temperature, when the Bethe model has a transition in field, contrary to the fully connected model that is always in the spin-glass phase. Sharing with finite-dimensional model the finite connectivity properties, the Bethe lattice is clearly a better starting point for an expansion with respect to the fully connected model. The present work is a first step towards the generalization of this new expansion to more difficult and interesting cases as the zero-temperature limit, where the expansion could lead to different results with respect to the standard one.

Self Care

MedlinePlus

... Beth Israel Heart Disease Diabetes Chronic Pain New Approaches to Chronic Disease Self Assessment Self Care Connections Experiences Research Learning Evaluation Print Email Self Care If you are ...

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

Jimenez-Arguello, Alejandro Marti

The study of the inner structure of hadrons allows us to understand the nature of the interactions between partons, quarks and gluons, described by Quantum Chromodynamics. The elastic scattering reactions, which have been studied in order to measure the nucleon form factors, are included in this frame. The inelastic scattering reactions are also included in this frame, they allow us to obtain information about the nucleon structure thanks to the development of the parton distribution functions (PDFs). While through elastic scattering we can obtain information about the charge distribution of the nucleon, and hence, about the spatial distribution of themore » partons, through inelastic scattering we obtain information about the momentum distributions of partons, by employing the PDFs. However, we can study the exclusive inelastic scattering reactions, such as the Deeply Virtual Compton Scattering (DVCS), wich allow us to access to the spatial and momentum distributions simultaneously. This is possible thanks to the generalized parton distributions (GPDs), which allow us to correlate both types of distributions. The process known as DVCS is the easiest way to access the GPDs. This process can be expressed as the scattering of an electron by a proton by means of a virtual photon with the result of the scattered initial particles plus a real photon. We find a process competing with DVCS known as Bethe-Heitler (BH), in which the real photon is radiated by the lepton rather than the quark. Due to the small cross section of DVCS, of the order of nb, in order to conduct these kind of experiments it is necessary to make use of facilities capable of providing high beam intensities. One of these facilities is the Thomas Jefferson National Accelerator Facility , where the experiment JLab E07-007, "Complete Separation of Virtual Photon and π⁰ Electroproduction Observables of Unpolarized Protons", took place during the months of October to December of 2010. The main goal of this experiment is the isolation of the contribution from the term coming form the DVCS from the interference term, resulting from the BH contribution. This isolation is known as "Rosenbluth Separation". The work presented in this thesis focuses on the analysis of the data stored by the electromagnetic calorimeter, employed for the detection of real photons. There is also a a theoretical introduction to the study of the nucleon structure, reviewing the concepts of form factors and parton distributions through elastic and inelastic processes. The computation of the photon leptoproduction cross section is described in detail, as well as the goals of experiment E07-007. This thesis also describes the analysis of the data stored by the electromagnetic calorimeter, with the purpose of obtaining the kinematic variables of the real photons resulting from DVCS reactions. Finally, it describes the selection of events from stored data, the applied cuts to kinematical variables and the background subtraction. Also, the process of extraction of the necessary observables for computing the photon leptoproduction cross section is described, along with the main steps followed to perform the Monte Carlo simulation used in this computation. The resulting cross sections are shown at the end of this thesis.« less

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

Jentschura, Ulrich D.; National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8401; Mohr, Peter J.

We describe the calculation of hydrogenic (one-loop) Bethe logarithms for all states with principal quantum numbers n{<=}200. While, in principle, the calculation of the Bethe logarithm is a rather easy computational problem involving only the nonrelativistic (Schroedinger) theory of the hydrogen atom, certain calculational difficulties affect highly excited states, and in particular states for which the principal quantum number is much larger than the orbital angular momentum quantum number. Two evaluation methods are contrasted. One of these is based on the calculation of the principal value of a specific integral over a virtual photon energy. The other method relies directlymore » on the spectral representation of the Schroedinger-Coulomb propagator. Selected numerical results are presented. The full set of values is available at arXiv.org/quant-ph/0504002.« less

Three-body Coulomb problem probed by mapping the Bethe surface in ionizing ion-atom collisions.

PubMed

Moshammer, R; Perumal, A; Schulz, M; Rodríguez, V D; Kollmus, H; Mann, R; Hagmann, S; Ullrich, J

2001-11-26

The three-body Coulomb problem has been explored in kinematically complete experiments on single ionization of helium by 100 MeV/u C(6+) and 3.6 MeV/u Au(53+) impact. Low-energy electron emission ( E(e)<150 eV) as a function of the projectile deflection theta(p) (momentum transfer), i.e., the Bethe surface [15], has been mapped with Delta theta(p)+/-25 nanoradian resolution at extremely large perturbations ( 3.6 MeV/u Au(53+)) where single ionization occurs at impact parameters of typically 10 times the He K-shell radius. The experimental data are not in agreement with state-of-the-art continuum distorted wave-eikonal initial state theory.

Determinant representation of the domain-wall boundary condition partition function of a Richardson-Gaudin model containing one arbitrary spin

NASA Astrophysics Data System (ADS)

Faribault, Alexandre; Tschirhart, Hugo; Muller, Nicolas

2016-05-01

In this work we present a determinant expression for the domain-wall boundary condition partition function of rational (XXX) Richardson-Gaudin models which, in addition to N-1 spins \\frac{1}{2}, contains one arbitrarily large spin S. The proposed determinant representation is written in terms of a set of variables which, from previous work, are known to define eigenstates of the quantum integrable models belonging to this class as solutions to quadratic Bethe equations. Such a determinant can be useful numerically since systems of quadratic equations are much simpler to solve than the usual highly nonlinear Bethe equations. It can therefore offer significant gains in stability and computation speed.

"Her mouth is medicine": Beth Brant and Paula Gunn Allen's decolonizing queer erotics.

PubMed

Burford, Arianne

2013-01-01

This article asserts the need to recognize the complexity of the theoretical work of more lesbian Native American writers, focusing specifically Beth Brant (Bay of Quinte Mohawk) and Paula Gunn Allen (Laguna Pueblo). Their poetry and short stories provide a theoretically nuanced analysis of how heteronormativity is intertwined in and dependent on colonialism, and thus a methodology for Queer Theory that requires an understanding of it in relation to colonialism. They reject heteronormative Pocahontas fantasies about Native women, offering a lesbian-based tactic for decolonization through the expression of erotic desire. This article demonstrates the endless possibilities for fierce queer resistance, revolutionary change, and healing from the trauma of genocide and the accompanying colonialist heteropatriarchal disciplining of Native women's bodies.

Momentum distributions for H 2 ( e , e ' p )

DOE PAGES

Ford, William P.; Jeschonnek, Sabine; Van Orden, J. W.

2014-12-29

[Background] A primary goal of deuteron electrodisintegration is the possibility of extracting the deuteron momentum distribution. This extraction is inherently fraught with difficulty, as the momentum distribution is not an observable and the extraction relies on theoretical models dependent on other models as input. [Purpose] We present a new method for extracting the momentum distribution which takes into account a wide variety of model inputs thus providing a theoretical uncertainty due to the various model constituents. [Method] The calculations presented here are using a Bethe-Salpeter like formalism with a wide variety of bound state wave functions, form factors, and finalmore » state interactions. We present a method to extract the momentum distributions from experimental cross sections, which takes into account the theoretical uncertainty from the various model constituents entering the calculation. [Results] In order to test the extraction pseudo-data was generated, and the extracted "experimental'' distribution, which has theoretical uncertainty from the various model inputs, was compared with the theoretical distribution used to generate the pseudo-data. [Conclusions] In the examples we compared the original distribution was typically within the error band of the extracted distribution. The input wave functions do contain some outliers which are discussed in the text, but at least this process can provide an upper bound on the deuteron momentum distribution. Due to the reliance on the theoretical calculation to obtain this quantity any extraction method should account for the theoretical error inherent in these calculations due to model inputs.« less

RITRACKS: A Software for Simulation of Stochastic Radiation Track Structure, Micro and Nanodosimetry, Radiation Chemistry and DNA Damage for Heavy Ions

NASA Technical Reports Server (NTRS)

Plante, I; Wu, H

2014-01-01

The code RITRACKS (Relativistic Ion Tracks) has been developed over the last few years at the NASA Johnson Space Center to simulate the effects of ionizing radiations at the microscopic scale, to understand the effects of space radiation at the biological level. The fundamental part of this code is the stochastic simulation of radiation track structure of heavy ions, an important component of space radiations. The code can calculate many relevant quantities such as the radial dose, voxel dose, and may also be used to calculate the dose in spherical and cylindrical targets of various sizes. Recently, we have incorporated DNA structure and damage simulations at the molecular scale in RITRACKS. The direct effect of radiations is simulated by introducing a slight modification of the existing particle transport algorithms, using the Binary-Encounter-Bethe model of ionization cross sections for each molecular orbitals of DNA. The simulation of radiation chemistry is done by a step-by-step diffusion-reaction program based on the Green's functions of the diffusion equation]. This approach is also used to simulate the indirect effect of ionizing radiation on DNA. The software can be installed independently on PC and tablets using the Windows operating system and does not require any coding from the user. It includes a Graphic User Interface (GUI) and a 3D OpenGL visualization interface. The calculations are executed simultaneously (in parallel) on multiple CPUs. The main features of the software will be presented.

From Waves to Particle Tracks and Quantum Probabilities

NASA Astrophysics Data System (ADS)

Falkenburg, Brigitte

Here, the measurement methods for identifying massive charged particles are investigated. They have been used from early cosmic ray studies up to the present day. Laws such as the classical Lorentz force and Einstein's relativistic kinematics were established before the rise of quantum mechanics. Later, it became crucial to measure the energy loss of charged particles in matter. In 1930, Bethe developed a semi-classical model based on the quantum mechanics of scattering. In the early 1930s, he and others calculated the passage of charged particles through matter including pair creation and bremsstrahlung. Due to missing trust in quantum electrodynamics, however, only semi-empirical methods were employed in order to estimate the mass and charge from the features of particle tracks. In 1932, Anderson inserted a lead plate into the cloud chamber in order to determine the flight direction and charge of the `positive electron'. In the 1940s, nuclear emulsions helped to resolve puzzles about particle identification and quantum electrodynamics. Later, the measurement theory was extended in a cumulative process by adding conservation laws for dynamic properties, probabilistic quantum formulas for resonances, scattering cross sections, etc. The measurement method was taken over from cosmic ray studies to the era of particle accelerators, and finally taken back from there to astroparticle physics. The measurement methods remained the same, but in the transition from particle to astroparticle physics the focus of interest shifted. Indeed, the experimental methods of both fields explore the grounds of `new physics' in complementary ways.

Global payment contract attitudes and comprehension among internal medicine physicians.

PubMed

Allen-Dicker, Joshua; Herzig, Shoshana J; Kerbel, Russell

2015-08-01

Global payment contracts (GPCs) are increasingly common agreements between insurance payers and healthcare providers that incorporate aspects of risk adjustment, capitation, and pay-for-performance. Physicians are often viewed as potential barriers to implementation of organizational change, but little is known about internist opinion on GPC involvement or specific internist attributes that might predict GPC support. We aimed to investigate internist and internal medicine subspecialist support of GPC involvement, and to identify associations among physician attributes, GPC knowledge, and GPC support. Cross-sectional. General medicine and internal medicine subspecialist physicians within the Beth Israel Deaconess Department of Medicine in Boston, Massachusetts, were surveyed 4 years after care organization entry into a GPC. Measurements collected included reported support for GPC involvement, reason for support, and demonstrated comprehension of key GPC details. Of the 281 respondents (49% response rate), 85% reported supporting involvement in a GPC. In a multivariate ordinal logistic regression model, exposure to prior information about GPCs, demonstrated comprehension of key GPC details, longer time since completion of residency, and lower clinical time commitment were all independently associated with higher levels of GPC involvement support. Four years since first engaging in a global payment contract, a majority of internal medicine physician respondents support this decision. Understanding predictors of physician support for GPC involvement within our care organization may help other health systems to approach organizational change. Health system leaders debating GPC involvement should consider engaging physicians via educational interventions geared toward improving GPC support.

Quantum integrability and functional equations

NASA Astrophysics Data System (ADS)

Volin, Dmytro

2010-03-01

In this thesis a general procedure to represent the integral Bethe Ansatz equations in the form of the Reimann-Hilbert problem is given. This allows us to study in simple way integrable spin chains in the thermodynamic limit. Based on the functional equations we give the procedure that allows finding the subleading orders in the solution of various integral equations solved to the leading order by the Wiener-Hopf technics. The integral equations are studied in the context of the AdS/CFT correspondence, where their solution allows verification of the integrability conjecture up to two loops of the strong coupling expansion. In the context of the two-dimensional sigma models we analyze the large-order behavior of the asymptotic perturbative expansion. Obtained experience with the functional representation of the integral equations allowed us also to solve explicitly the crossing equations that appear in the AdS/CFT spectral problem.

Chapter 6 Quantum Mechanical Methods for Loss-Excitation and Loss-Ionization in Fast Ion-Atom Collisions

NASA Astrophysics Data System (ADS)

Belkic, Dzevad

Inelastic collisions between bare nuclei and hydrogen-like atomic systems are characterized by three main channels: electron capture, excitation, and ionization. Capture dominates at lower energies, whereas excitation and ionization prevail at higher impact energies. At intermediate energies and in the region of resonant scattering near the Massey peak, all three channels become competitive. For dressed or clothed nuclei possessing electrons, such as hydrogen-like ions, several additional channels open up, including electron loss (projectile ionization or stripping). The most important aspect of electron loss is the competition between one- and two-electron processes. Here, in a typical one-electron process, the projectile emits an electron, whereas the target final and initial states are the same. A prototype of double-electron transitions in loss processes is projectile ionization accompanied with an alteration of the target state. In such a two-electron process, the target could be excited or ionized. The relative importance of these loss channels with single- and double-electron transitions involving collisions of dressed projectiles with atomic systems is also strongly dependent on the value of the impact energy. Moreover, impact energies determine which theoretical method is likely to be more appropriate to use for predictions of cross sections. At low energies, an expansion of total scattering wave functions in terms of molecular orbitals is adequate. This is because the projectile spends considerable time in the vicinity of the target, and as a result, a compound system comprised of the projectile and the target can be formed in a metastable molecular state which is prone to decay. At high energies, a perturbation series expansion is more appropriate in terms of powers of interaction potentials. In the intermediate energy region, atomic orbitals are often used with success while expanding the total scattering wave functions. The present work is focused on quantum mechanical perturbation theories applied to electron loss collisions involving two hydrogen-like atoms. Both the one- and two-electron transitions (target unaffected by collision, as well as loss-ionization) are thoroughly examined in various intervals of impact energies varying from the threshold via the Massey peak to the Bethe asymptotic region. Systematics are established for the fast, simple, and accurate computations of cross sections for loss-excitation and loss-ionization accounting for the entire spectra of all four particles, including two free electrons and two free protons. The expounded algorithmic strategy of quantum mechanical methodologies is of great importance for wide applications to particle transport physics, especially in fusion research and hadron radiotherapy. This should advantageously replace the current overwhelming tendency in these fields for using phenomenological modeling with artificial functions extracted from fitting the existing experimental/theoretical data bases for cross sections.

From ‘Nerve Fiber Regeneration’ to ‘Functional Changes’ in the Human Brain—On the Paradigm-Shifting Work of the Experimental Physiologist Albrecht Bethe (1872–1954) in Frankfurt am Main

PubMed Central

Stahnisch, Frank W.

2016-01-01

Until the beginning 1930’s the traditional dogma that the human central nervous system (CNS) did not possess any abilities to adapt functionally to degenerative processes and external injuries loomed large in the field of the brain sciences (Hirnforschung). Cutting-edge neuroanatomists, such as the luminary Wilhelm Waldeyer (1836–1921) in Germany or the Nobel Prize laureate Santiago Ramón y Cajal (1852–1934) in Spain, debated any regenerative and thus “plastic” properties in the human brain. A renewed interest arose in the scientific community to investigate the pathologies and the healing processes in the human CNS after the return of the high number of brain injured war veterans from the fronts during and after the First World War (1914–1918). A leading research center in this area was the “Institute for the Scientific Study of the Effects of Brain Injuries,” which the neurologist Ludwig Edinger (1855–1918) had founded shortly before the war. This article specifically deals with the physiological research on nerve fiber plasticity by Albrecht Bethe (1872–1954) at the respective institute of the University of Frankfurt am Main. Bethe conducted here his paradigmatic experimental studies on the pathophysiological and clinical phenomena of peripheral and CNS regeneration. PMID:26941616

The open XXX spin chain in the SoV framework: scalar product of separate states

NASA Astrophysics Data System (ADS)

Kitanine, N.; Maillet, J. M.; Niccoli, G.; Terras, V.

2017-06-01

We consider the XXX open spin-1/2 chain with the most general non-diagonal boundary terms, that we solve by means of the quantum separation of variables (SoV) approach. We compute the scalar products of separate states, a class of states which notably contains all the eigenstates of the model. As usual for models solved by SoV, these scalar products can be expressed as some determinants with a non-trivial dependance in terms of the inhomogeneity parameters that have to be introduced for the method to be applicable. We show that these determinants can be transformed into alternative ones in which the homogeneous limit can easily be taken. These new representations can be considered as generalizations of the well-known determinant representation for the scalar products of the Bethe states of the periodic chain. In the particular case where a constraint is applied on the boundary parameters, such that the transfer matrix spectrum and eigenstates can be characterized in terms of polynomial solutions of a usual T-Q equation, the scalar product that we compute here corresponds to the scalar product between two off-shell Bethe-type states. If in addition one of the states is an eigenstate, the determinant representation can be simplified, hence leading in this boundary case to direct analogues of algebraic Bethe ansatz determinant representations of the scalar products for the periodic chain.

Chemical decontamination technical resources at Los Alamos National Laboratory (2008)

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

Moore, Murray E

This document supplies information resources for a person seeking to create planning or pre-planning documents for chemical decontamination operations. A building decontamination plan can be separated into four different sections: Pre-planning, Characterization, Decontamination (Initial response and also complete cleanup), and Clearance. Of the identified Los Alamos resources, they can be matched with these four sections: Pre-planning -- Dave Seidel, EO-EPP, Emergency Planning and Preparedness; David DeCroix and Bruce Letellier, D-3, Computational fluids modeling of structures; Murray E. Moore, RP-2, Aerosol sampling and ventilation engineering. Characterization (this can include development projects) -- Beth Perry, IAT-3, Nuclear Counterterrorism Response (SNIPER database); Fernandomore » Garzon, MPA-11, Sensors and Electrochemical Devices (development); George Havrilla, C-CDE, Chemical Diagnostics and Engineering; Kristen McCabe, B-7, Biosecurity and Public Health. Decontamination -- Adam Stively, EO-ER, Emergency Response; Dina Matz, IHS-IP, Industrial hygiene; Don Hickmott, EES-6, Chemical cleanup. Clearance (validation) -- Larry Ticknor, CCS-6, Statistical Sciences.« less

Tetraquark bound states in a Bethe-Salpeter approach

NASA Astrophysics Data System (ADS)

Heupel, Walter; Eichmann, Gernot; Fischer, Christian S.

2012-12-01

We determine the mass of tetraquark bound states from a coupled system of covariant Bethe-Salpeter equations. Similar in spirit to the quark-diquark model of the nucleon, we approximate the full four-body equation for the tetraquark by a coupled set of two-body equations with meson and diquark constituents. These are calculated from their quark and gluon substructure using a phenomenologically well-established quark-gluon interaction. For the lightest scalar tetraquark we find a mass of the order of 400 MeV and a wave function dominated by the pion-pion constituents. Both results are in agreement with a meson molecule picture for the f0 (600). Our results furthermore suggest the presence of a potentially narrow all-charm tetraquark in the mass region 5-6 GeV.

Integrability and superintegrability of the generalized n-level many-mode Jaynes-Cummings and Dicke models

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

Skrypnyk, T.

2009-10-15

We analyze symmetries of the integrable generalizations of Jaynes-Cummings and Dicke models associated with simple Lie algebras g and their reductive subalgebras g{sub K}[T. Skrypnyk, 'Generalized n-level Jaynes-Cummings and Dicke models, classical rational r-matrices and nested Bethe ansatz', J. Phys. A: Math. Theor. 41, 475202 (2008)]. We show that their symmetry algebras contain commutative subalgebras isomorphic to the Cartan subalgebras of g, which can be added to the commutative algebras of quantum integrals generated with the help of the quantum Lax operators. We diagonalize additional commuting integrals and constructed with their help the most general integrable quantum Hamiltonian of themore » generalized n-level many-mode Jaynes-Cummings and Dicke-type models using nested algebraic Bethe ansatz.« less

Magnonic qudit and algebraic Bethe Ansatz

NASA Astrophysics Data System (ADS)

Lulek, B.; Lulek, T.

2010-03-01

A magnonic qudit is proposed as the memory unit of a register of a quantum computer. It is the N-dimensional space, extracted from the 2N-dimensional space of all quantum states of the magnetic Heisenberg ring of N spins 1/2, as the space of all states of a single magnon. Three bases: positional, momentum, and that of Weyl duality are described, together with appropriate Fourier and Kostka transforms. It is demonstrated how exact Bethe Ansatz (BA) eigenfunctions, classified in terms of rigged string configurations, can be coded using a collection of magnonic qudits. To this aim, the algebraic BA is invoked, such that a single magnonic qudit is prepared in a state corresponding to a magnon in one of the states provided by spectral parameters emerging from the corresponding BA equations.

Computational Pathology to Discriminate Benign from Malignant Intraductal Proliferations of the Breast

PubMed Central

Oh, Eun-Yeong; Lerwill, Melinda F.; Brachtel, Elena F.; Jones, Nicholas C.; Knoblauch, Nicholas W.; Montaser-Kouhsari, Laleh; Johnson, Nicole B.; Rao, Luigi K. F.; Faulkner-Jones, Beverly; Wilbur, David C.; Schnitt, Stuart J.; Beck, Andrew H.

2014-01-01

The categorization of intraductal proliferative lesions of the breast based on routine light microscopic examination of histopathologic sections is in many cases challenging, even for experienced pathologists. The development of computational tools to aid pathologists in the characterization of these lesions would have great diagnostic and clinical value. As a first step to address this issue, we evaluated the ability of computational image analysis to accurately classify DCIS and UDH and to stratify nuclear grade within DCIS. Using 116 breast biopsies diagnosed as DCIS or UDH from the Massachusetts General Hospital (MGH), we developed a computational method to extract 392 features corresponding to the mean and standard deviation in nuclear size and shape, intensity, and texture across 8 color channels. We used L1-regularized logistic regression to build classification models to discriminate DCIS from UDH. The top-performing model contained 22 active features and achieved an AUC of 0.95 in cross-validation on the MGH data-set. We applied this model to an external validation set of 51 breast biopsies diagnosed as DCIS or UDH from the Beth Israel Deaconess Medical Center, and the model achieved an AUC of 0.86. The top-performing model contained active features from all color-spaces and from the three classes of features (morphology, intensity, and texture), suggesting the value of each for prediction. We built models to stratify grade within DCIS and obtained strong performance for stratifying low nuclear grade vs. high nuclear grade DCIS (AUC = 0.98 in cross-validation) with only moderate performance for discriminating low nuclear grade vs. intermediate nuclear grade and intermediate nuclear grade vs. high nuclear grade DCIS (AUC = 0.83 and 0.69, respectively). These data show that computational pathology models can robustly discriminate benign from malignant intraductal proliferative lesions of the breast and may aid pathologists in the diagnosis and classification of these lesions. PMID:25490766

Cummings/Ju - Harvard; Emory | Division of Cancer Prevention

Cancer.gov

Principal Investigator: Richard D Cummings, PhDInstitution: Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA Principal Investigator: Tongzhong Ju, MD, PhDInstitution: Emory University, Atlanta, GA |

Topology and Foundations of Quantum Algorithms

DTIC Science & Technology

2005-07-01

Several visitors to UCSD and IU were also partially supported for short visits: Markus Hunziker, Vaughn Jones, Alexei Kitaev, Burt Kostant, Hanspeter Kraft, Peter Love, Mary Beth Ruskai, Yaoyun Shi and Richard Stong. 5

DOE Research and Development Accomplishments Interesting Insights

Science.gov Websites

There secrets powering the stars [Bethe] Synthesis of the Elements in the Stars [Fowler] blackbody form organic synthesis [Schrock/Grubbs] provided the theoretical explanation of the fractional quantum Hall

77 FR 74479 - Environmental Impacts Statements; Notice of Availability

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-14

..., Contact: Mary Beth Burandt 888-829-6347. EIS No. 20120386, Final EIS, FTA, MD, Red Line Project... Dunes National Recreation Area, Siuslaw National Forest, Coos, Douglas, and Lane Counties OR, Comment...

Symmetry-preserving contact interaction model for heavy-light mesons

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

Serna, F. E.; Brito, M. A.; Krein, G.

2016-01-22

We use a symmetry-preserving regularization method of ultraviolet divergences in a vector-vector contact interaction model for low-energy QCD. The contact interaction is a representation of nonperturbative kernels used Dyson-Schwinger and Bethe-Salpeter equations. The regularization method is based on a subtraction scheme that avoids standard steps in the evaluation of divergent integrals that invariably lead to symmetry violation. Aiming at the study of heavy-light mesons, we have implemented the method to the pseudoscalar π and K mesons. We have solved the Dyson-Schwinger equation for the u, d and s quark propagators, and obtained the bound-state Bethe-Salpeter amplitudes in a way thatmore » the Ward-Green-Takahashi identities reflecting global symmetries of the model are satisfied for arbitrary routing of the momenta running in loop integrals.« less

On Condensation Properties of Bethe Roots Associated with the XXZ Chain

NASA Astrophysics Data System (ADS)

Kozlowski, Karol K.

2018-02-01

I prove that the Bethe roots describing either the ground state or a certain class of "particle-hole" excited states of the XXZ spin-1/2 chain in any sector with magnetisation m \\in [0;1/2] exist, are uniquely defined, and form, in the infinite volume limit, a dense distribution on a subinterval of R. The results hold for any value of the anisotropy {Δ ≥ -1}. In fact, I establish an even stronger result, namely the existence of an all order asymptotic expansion of the counting function associated with such roots. As a corollary, these results allow one to prove the existence and form of the infinite volume limit of various observables attached to the model -the excitation energy, momentum, the zero temperature correlation functions, so as to name a few- that were argued earlier in the literature.

NASA Astrophysics Data System (ADS)

Schweber, Silvan S.

2014-06-01

Some facets of the life of Hans Bethe after World War II are presented to illustrate how Paul Forman's works, and in particular his various theses—on mathematics and physics in Wilhelmine and Weimar Germany, on physics in the immediate post-World War II period, and on postmodernity—have influenced my biography of Bethe. Some aspects of the history of post-World War II quantum field theory, of solid state/condensed matter physics, and of the development of neoliberalism—the commitment to the belief that the market knows best, to free trade, to enhanced privatization, and to a drastic reduction of the government's role in regulating the economy—are reviewed in order to make some observations regarding certain "top-down" views in solid state physics in postmodernity, the economic and cultural condition of many Western societies since the 1980s, the decade in which many historians assume modernity to have ended.

Mayer-cluster expansion of instanton partition functions and thermodynamic bethe ansatz

NASA Astrophysics Data System (ADS)

Meneghelli, Carlo; Yang, Gang

2014-05-01

In [19] Nekrasov and Shatashvili pointed out that the = 2 instanton partition function in a special limit of the Ω-deformation parameters is characterized by certain thermodynamic Bethe ansatz (TBA) like equations. In this work we present an explicit derivation of this fact as well as generalizations to quiver gauge theories. To do so we combine various techniques like the iterated Mayer expansion, the method of expansion by regions, and the path integral tricks for non-perturbative summation. The TBA equations derived entirely within gauge theory have been proposed to encode the spectrum of a large class of quantum integrable systems. We hope that the derivation presented in this paper elucidates further this completely new point of view on the origin, as well as on the structure, of TBA equations in integrable models.

A Riemann-Hilbert formulation for the finite temperature Hubbard model

NASA Astrophysics Data System (ADS)

Cavaglià, Andrea; Cornagliotto, Martina; Mattelliano, Massimo; Tateo, Roberto

2015-06-01

Inspired by recent results in the context of AdS/CFT integrability, we reconsider the Thermodynamic Bethe Ansatz equations describing the 1D fermionic Hubbard model at finite temperature. We prove that the infinite set of TBA equations are equivalent to a simple nonlinear Riemann-Hilbert problem for a finite number of unknown functions. The latter can be transformed into a set of three coupled nonlinear integral equations defined over a finite support, which can be easily solved numerically. We discuss the emergence of an exact Bethe Ansatz and the link between the TBA approach and the results by Jüttner, Klümper and Suzuki based on the Quantum Transfer Matrix method. We also comment on the analytic continuation mechanism leading to excited states and on the mirror equations describing the finite-size Hubbard model with twisted boundary conditions.

Bethe-Boltzmann hydrodynamics and spin transport in the XXZ chain

NASA Astrophysics Data System (ADS)

Bulchandani, Vir B.; Vasseur, Romain; Karrasch, Christoph; Moore, Joel E.

2018-01-01

Quantum integrable systems, such as the interacting Bose gas in one dimension and the XXZ quantum spin chain, have an extensive number of local conserved quantities that endow them with exotic thermalization and transport properties. We discuss recently introduced hydrodynamic approaches for such integrable systems from the viewpoint of kinetic theory and extend the previous works by proposing a numerical scheme to solve the hydrodynamic equations for finite times and arbitrary locally equilibrated initial conditions. We then discuss how such methods can be applied to describe nonequilibrium steady states involving ballistic heat and spin currents. In particular, we show that the spin Drude weight in the XXZ chain, previously accessible only by rigorous techniques of limited scope or controversial thermodynamic Bethe ansatz arguments, may be evaluated from hydrodynamics in very good agreement with density-matrix renormalization group calculations.

Decay width of hadronic molecule structure for quarks

NASA Astrophysics Data System (ADS)

Chen, Xiaozhao; Lü, Xiaofu

2018-06-01

Based on the general form of the Bethe-Salpeter wave functions for the bound states consisting of two vector fields, we obtain the general formulas for the decay widths of molecular states composed of two heavy vector mesons with arbitrary spin and parity into a heavy meson plus a light meson. In this approach, our attention is still focused on the internal structure of heavy vector mesons in the molecular state. According to the molecule state model of exotic meson, we give the generalized Bethe-Salpeter wave function of molecular state as a four-quark state. Then the observed Y (3940 ) state is considered as a molecular state consisting of two heavy vector mesons D*0D¯*0 and the strong Y (3940 )→J /ψ ω decay width is calculated. The numerical result is consistent with the experimental values.

Cyclotomic Gaudin Models: Construction and Bethe Ansatz

NASA Astrophysics Data System (ADS)

Vicedo, Benoît; Young, Charles

2016-05-01

To any finite-dimensional simple Lie algebra g and automorphism {σ: gto g we associate a cyclotomic Gaudin algebra. This is a large commutative subalgebra of {U(g)^{⊗ N}} generated by a hierarchy of cyclotomic Gaudin Hamiltonians. It reduces to the Gaudin algebra in the special case {σ =id}. We go on to construct joint eigenvectors and their eigenvalues for this hierarchy of cyclotomic Gaudin Hamiltonians, in the case of a spin chain consisting of a tensor product of Verma modules. To do so we generalize an approach to the Bethe ansatz due to Feigin, Frenkel and Reshetikhin involving vertex algebras and the Wakimoto construction. As part of this construction, we make use of a theorem concerning cyclotomic coinvariants, which we prove in a companion paper. As a byproduct, we obtain a cyclotomic generalization of the Schechtman-Varchenko formula for the weight function.

Simple and accurate sum rules for highly relativistic systems

NASA Astrophysics Data System (ADS)

Cohen, Scott M.

2005-03-01

In this paper, I consider the Bethe and Thomas-Reiche-Kuhn sum rules, which together form the foundation of Bethe's theory of energy loss from fast charged particles to matter. For nonrelativistic target systems, the use of closure leads directly to simple expressions for these quantities. In the case of relativistic systems, on the other hand, the calculation of sum rules is fraught with difficulties. Various perturbative approaches have been used over the years to obtain relativistic corrections, but these methods fail badly when the system in question is very strongly bound. Here, I present an approach that leads to relatively simple expressions yielding accurate sums, even for highly relativistic many-electron systems. I also offer an explanation for the difference between relativistic and nonrelativistic sum rules in terms of the Zitterbewegung of the electrons.

Effect of ladder diagrams on optical absorption spectra in a quasiparticle self-consistent GW framework

NASA Astrophysics Data System (ADS)

Cunningham, Brian; Grüning, Myrta; Azarhoosh, Pooya; Pashov, Dimitar; van Schilfgaarde, Mark

2018-03-01

We present an approach to calculate the optical absorption spectra that combines the quasiparticle self-consistent GW method [Phys. Rev. B 76, 165106 (2007), 10.1103/PhysRevB.76.165106] for the electronic structure with the solution of the ladder approximation to the Bethe-Salpeter equation for the macroscopic dielectric function. The solution of the Bethe-Salpeter equation has been implemented within an all-electron framework, using a linear muffin-tin orbital basis set, with the contribution from the nonlocal self-energy to the transition dipole moments (in the optical limit) evaluated explicitly. This approach addresses those systems whose electronic structure is poorly described within the standard perturbative GW approaches with density-functional theory calculations as a starting point. The merits of this approach have been exemplified by calculating optical absorption spectra of a strongly correlated transition metal oxide, NiO, and a narrow gap semiconductor, Ge. In both cases, the calculated spectrum is in good agreement with the experiment. It is also shown that for systems whose electronic structure is well-described within the standard perturbative GW , such as Si, LiF, and h -BN , the performance of the present approach is in general comparable to the standard GW plus Bethe-Salpeter equation. It is argued that both vertex corrections to the electronic screening and the electron-phonon interaction are responsible for the observed systematic overestimation of the fundamental band gap and spectrum onset.

Study of generalized parton distributions and deeply virtual compton scattering on the nucleon with the CLAS and CLAS12 detectors at the Jefferson Laboratory

NASA Astrophysics Data System (ADS)

Guegan, Baptiste

The Generalized Parton Distributions (GPDs) provide a new description of the nucleon structure in terms of its elementary constituents, the quarks and the gluons. The GPDs give access to a unified picture of the nucleon, correlating the information obtained from the measurements of the Form Factors and the Parton Distribution Functions. They describe the correlation between the transverse position and the longitudinal momentum fraction of the partons in the nucleon. Deeply Virtual Compton Scattering (DVCS), the electroproduction of a real photon on a single quark of the nucleon eN → eN'gamma , is the most straightforward exclusive process allowing access to the GPDs. The DVCS process interferes with the Bethe-Heitler (BH) process, in which the real photon is emitted by either the incoming or the scattered electron instead of the nucleon. A dedicated experiment to study DVCS with the CLAS detector of Jefferson Lab has been carried out using a 5.883 GeV polarized electron beam and an unpolarized hydrogen target, allowing to collect DVCS events in the widest kinematic range ever explored in the valence region : 1 < Q2 < 4.6 GeV2, 0.1 < xB < 0.58, 0.09 < -t < 3 GeV2. We will present preliminary results on the extraction of the unpolarized and the difference of polarized DVCS cross sections. We will show a preliminary extraction of the GPDs using the latest fitting code procedure on our data, and a preliminary interpretation of the results.

Advanced Illness: Holding on and Letting Go

MedlinePlus

... Life Care Association (formerly National Association of Professional Geriatric Care Managers) This professional group offers a listing ... Reviewed by Beth MacLeod, LCSW, Care Consultations and Therapy, San Francisco, CA. © 2013 Family Caregiver Alliance. All ...

Misconceptions impairing the validity of the stopping power tables in the SRIM library and suggestions for doing better in the future

NASA Astrophysics Data System (ADS)

Wittmaack, Klaus

2016-08-01

The popular SRIM library delivers data and simulation codes for describing the slowing down of energetic atoms in matter. This study explored the validity of the tables containing cross sections for electronic and nuclear stopping together with the respective range parameters. The electronic stopping cross sections Se were produced, much like in previous and subsequent attempts of other groups, by bringing together the limited number of available experimental results in the form of ratios, r(Z1, He, υ) = Se(Z1, Z2, υ)/Se(He, Z2, υ). Z1 and Z2 denote the atomic numbers of projectiles (velocity υ) and target atoms, respectively. Reference data for He impact are available in reasonable volume only for about 15% of all solid targets; missing information has to be derived by interpolation. The concept of data evaluation is based on the assumption that the Bethe-Bloch (BB) theory, developed for bare projectiles, can serve as a guide at all velocities. For the purpose in question, the theory features an indispensible property: Z1 and Z2 appear as straight pre-factors, not in coupled form, Se,BB (υ) ∝ Z12 Z2 L (Z2, υ) , with L(Z2, υ) representing the stopping number. Therefore, Z2 and L(Z2, υ) cancel out when taking ratios for fixed Z1 so that data for arbitrary Z2 may be combined in one set of r-values to determine the best fit rfit(Z1, He, υ). The stopping cross sections of interest are then derived as Se(Z1, Z2, υ) = rfit(Z1, He, υ) Se(He, Z2, υ). At low energies these results were often refined, Se ⇒ Se,f, to account for experimental data that did not comply with the anticipated Z2-independent trend. Major findings and suggestions are as follows: (i) At high velocities, υ > 4Z12/3υ0 (Bohr velocity υ0), the SRIM predictions (have to) rely primarily on BB theory. (ii) At intermediate velocities, i.e., around the Bragg peak, SRIM appears to produce reasonable results (ca. ±15%). (iii) Below the Bragg peak the tabulated data often deviate strongly and inconsistently from the predictions of Lindhard-Scharff (LS) theory; they also exhibit various forms of exotic velocity dependence. These deviations are primarily due to the fact that the range of validity of BB theory is artificially extended to velocities at which the 'effective-charge' concept is assumed to be applicable. Coupled Z1,2 scaling as in theories of LS or Firsov would be much more appropriate. Overall, the electronic stopping cross sections by SRIM are of unpredictable value and often strongly misleading below 1 MeV/u. (iv) Another consequence of the tight link to the Z1,2 dependence of BB theory is that only 2 × 92 master sets of electronic stopping cross sections were required to generate all conceivable 89 × 92 tables from Se,f-ratios for elemental targets (the tables for H, He and Li projectiles are derived separately). The information contained in the SRIM library at large thus exhibits a highly redundant character. (v) The nuclear stopping cross sections Sn mirror the predictions of the universal potential due by Ziegler, Biersack and Littmark, which differ from alternative suggestions typically by less than 15%. With this uncertainty, range distributions may be calculated with the TRIM program of SRIM, but only at energies where Sn dominates so that uncertainties in Se play a minor role. (vi) As a side aspect, an example is presented illustrating the efforts required to identify incorrect experimental data, notably when respected authors are accountable. (vii) Other approaches to establish stopping power tables are shown to be subject to the same problems as SRIM. It is recommended to add a warning to all theses tables, informing users at which energies the data are likely to lack reliability. (viii) The currently unacceptable quality of Se,f-data below 1 MeV/u could be improved significantly in the future if the user friendly TRIM(SRIM) code were modified to allow simulations with a free choice of nuclear and electronic stopping cross sections. Researchers would thus be enabled to identify optimum input parameters for reproducing measured range distributions at energies at which Sn and Se are often of similar magnitude so that their contribution to the total energy loss is difficult to quantify without simulations.

R matrices of three-state Hamiltonians solvable by coordinate Bethe ansatz

NASA Astrophysics Data System (ADS)

Fonseca, T.; Frappat, L.; Ragoucy, E.

2015-01-01

We review some of the strategies that can be implemented to infer an R-matrix from the knowledge of its Hamiltonian. We apply them to the classification achieved in Crampé, Frappat, and Ragoucy, J. Phys. A 46, 405001 (2013), on three state U(1)-invariant Hamiltonians solvable by coordinate Bethe ansatz, focusing on models for which the S-matrix is not trivial. For the 19-vertex solutions, we recover the R-matrices of the well-known Zamolodchikov-Fateev and Izergin-Korepin models. We point out that the generalized Bariev Hamiltonian is related to both main and special branches studied by Martins in Nucl. Phys. B 874, 243 (2013), that we prove to generate the same Hamiltonian. The 19-vertex SpR model still resists to the analysis, although we are able to state some no-go theorems on its R-matrix. For 17-vertex Hamiltonians, we produce a new R-matrix.

Quantum criticality in the spin-1/2 Heisenberg chain system copper pyrazine dinitrate

PubMed Central

Breunig, Oliver; Garst, Markus; Klümper, Andreas; Rohrkamp, Jens; Turnbull, Mark M.; Lorenz, Thomas

2017-01-01

Low-dimensional quantum magnets promote strong correlations between magnetic moments that lead to fascinating quantum phenomena. A particularly interesting system is the antiferromagnetic spin-1/2 Heisenberg chain because it is exactly solvable by the Bethe-Ansatz method. It is approximately realized in the magnetic insulator copper pyrazine dinitrate, providing a unique opportunity for a quantitative comparison between theory and experiment. We investigate its thermodynamic properties with a particular focus on the field-induced quantum phase transition. Thermal expansion, magnetostriction, specific heat, magnetization, and magnetocaloric measurements are found to be in excellent agreement with exact Bethe-Ansatz predictions. Close to the critical field, thermodynamics obeys the expected quantum critical scaling behavior, and in particular, the magnetocaloric effect and the Grüneisen parameters diverge in a characteristic manner. Beyond its importance for quantum magnetism, our study establishes a paradigm of a quantum phase transition, which illustrates fundamental principles of quantum critical thermodynamics. PMID:29282449

Simple and Accurate Method for Central Spin Problems

NASA Astrophysics Data System (ADS)

Lindoy, Lachlan P.; Manolopoulos, David E.

2018-06-01

We describe a simple quantum mechanical method that can be used to obtain accurate numerical results over long timescales for the spin correlation tensor of an electron spin that is hyperfine coupled to a large number of nuclear spins. This method does not suffer from the statistical errors that accompany a Monte Carlo sampling of the exact eigenstates of the central spin Hamiltonian obtained from the algebraic Bethe ansatz, or from the growth of the truncation error with time in the time-dependent density matrix renormalization group (TDMRG) approach. As a result, it can be applied to larger central spin problems than the algebraic Bethe ansatz, and for longer times than the TDMRG algorithm. It is therefore an ideal method to use to solve central spin problems, and we expect that it will also prove useful for a variety of related problems that arise in a number of different research fields.

Spherical Hecke algebra in the Nekrasov-Shatashvili limit

NASA Astrophysics Data System (ADS)

Bourgine, Jean-Emile

2015-01-01

The Spherical Hecke central (SHc) algebra has been shown to act on the Nekrasov instanton partition functions of gauge theories. Its presence accounts for both integrability and AGT correspondence. On the other hand, a specific limit of the Omega background, introduced by Nekrasov and Shatashvili (NS), leads to the appearance of TBA and Bethe like equations. To unify these two points of view, we study the NS limit of the SHc algebra. We provide an expression of the instanton partition function in terms of Bethe roots, and define a set of operators that generates infinitesimal variations of the roots. These operators obey the commutation relations defining the SHc algebra at first order in the equivariant parameter ɛ 2. Furthermore, their action on the bifundamental contributions reproduces the Kanno-Matsuo-Zhang transformation. We also discuss the connections with the Mayer cluster expansion approach that leads to TBA-like equations.

How Inhomogeneous Site Percolation Works on Bethe Lattices: Theory and Application

NASA Astrophysics Data System (ADS)

Ren, Jingli; Zhang, Liying; Siegmund, Stefan

2016-03-01

Inhomogeneous percolation, for its closer relationship with real-life, can be more useful and reasonable than homogeneous percolation to illustrate the critical phenomena and dynamical behaviour of complex networks. However, due to its intricacy, the theoretical framework of inhomogeneous percolation is far from being complete and many challenging problems are still open. In this paper, we first investigate inhomogeneous site percolation on Bethe Lattices with two occupation probabilities, and then extend the result to percolation with m occupation probabilities. The critical behaviour of this inhomogeneous percolation is shown clearly by formulating the percolation probability with given occupation probability p, the critical occupation probability , and the average cluster size where p is subject to . Moreover, using the above theory, we discuss in detail the diffusion behaviour of an infectious disease (SARS) and present specific disease-control strategies in consideration of groups with different infection probabilities.

Bethe lattice approach and relaxation dynamics study of spin-crossover materials

NASA Astrophysics Data System (ADS)

Oke, Toussaint Djidjoho; Hontinfinde, Félix; Boukheddaden, Kamel

2015-07-01

Dynamical properties of Prussian blue analogs and spin-crossover materials are investigated in the framework of a Blume-Emery-Griffiths (BEG) spin-1 model, where states ±1 and 0 represent the high-spin (HS) state and the low-spin state, respectively. The quadrupolar interaction depends on the temperature in the form . Magnetic interactions are controlled by a factor such that for (), magnetic ordering is not expected. The model is exactly solved using the Bethe lattice approach for the equilibrium properties. The results are closer to those calculated by numerical simulations with suitable Arrhenius-type transition rates. The study of relaxation processes of non-equilibrium HS states revealed one-step nonlinear sigmoidal relaxation curves of the HS fraction at low temperatures. We found that increasing the magnetic interactions leads to the appearance of a plateau in the thermal hysteresis as well as in the relaxation curves of the HS fraction at low temperature.

The integrable quantum group invariant A2n-1(2) and Dn+1(2) open spin chains

NASA Astrophysics Data System (ADS)

Nepomechie, Rafael I.; Pimenta, Rodrigo A.; Retore, Ana L.

2017-11-01

A family of A2n(2) integrable open spin chains with Uq (Cn) symmetry was recently identified in arxiv:arXiv:1702.01482. We identify here in a similar way a family of A2n-1(2) integrable open spin chains with Uq (Dn) symmetry, and two families of Dn+1(2) integrable open spin chains with Uq (Bn) symmetry. We discuss the consequences of these symmetries for the degeneracies and multiplicities of the spectrum. We propose Bethe ansatz solutions for two of these models, whose completeness we check numerically for small values of n and chain length N. We find formulas for the Dynkin labels in terms of the numbers of Bethe roots of each type, which are useful for determining the corresponding degeneracies. In an appendix, we briefly consider Dn+1(2) chains with other integrable boundary conditions, which do not have quantum group symmetry.

Statistical analysis of loopy belief propagation in random fields

NASA Astrophysics Data System (ADS)

Yasuda, Muneki; Kataoka, Shun; Tanaka, Kazuyuki

2015-10-01

Loopy belief propagation (LBP), which is equivalent to the Bethe approximation in statistical mechanics, is a message-passing-type inference method that is widely used to analyze systems based on Markov random fields (MRFs). In this paper, we propose a message-passing-type method to analytically evaluate the quenched average of LBP in random fields by using the replica cluster variation method. The proposed analytical method is applicable to general pairwise MRFs with random fields whose distributions differ from each other and can give the quenched averages of the Bethe free energies over random fields, which are consistent with numerical results. The order of its computational cost is equivalent to that of standard LBP. In the latter part of this paper, we describe the application of the proposed method to Bayesian image restoration, in which we observed that our theoretical results are in good agreement with the numerical results for natural images.

Real-structure effects: Band gaps of Mg_xZn_{1-x}O, Cd_xZn_{1-x}O, and n-type ZnO from ab-initio calculations

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

Schleife, A; Bechstedt, F

2012-02-15

Many-body perturbation theory is applied to compute the quasiparticle electronic structures and the optical-absorption spectra (including excitonic effects) for several transparent conducting oxides. We discuss HSE+G{sub 0}W{sub 0} results for band structures, fundamental band gaps, and effective electron masses of MgO, ZnO, CdO, SnO{sub 2}, SnO, In{sub 2}O{sub 3}, and SiO{sub 2}. The Bethe-Salpeter equation is solved to account for excitonic effects in the calculation of the frequency-dependent absorption coefficients. We show that the HSE+G{sub 0}W{sub 0} approach and the solution of the Bethe-Salpeter equation are very well-suited to describe the electronic structure and the optical properties of various transparentmore » conducting oxides in good agreement with experiment.« less

Periodic p-adic Gibbs Measures of q-State Potts Model on Cayley Trees I: The Chaos Implies the Vastness of the Set of p-Adic Gibbs Measures

NASA Astrophysics Data System (ADS)

Ahmad, Mohd Ali Khameini; Liao, Lingmin; Saburov, Mansoor

2018-06-01

We study the set of p-adic Gibbs measures of the q-state Potts model on the Cayley tree of order three. We prove the vastness of the set of the periodic p-adic Gibbs measures for such model by showing the chaotic behavior of the corresponding Potts-Bethe mapping over Q_p for the prime numbers p≡1 (mod 3). In fact, for 0< |θ -1|_p< |q|_p^2 < 1 where θ =\\exp _p(J) and J is a coupling constant, there exists a subsystem that is isometrically conjugate to the full shift on three symbols. Meanwhile, for 0< |q|_p^2 ≤ |θ -1|_p< |q|_p < 1, there exists a subsystem that is isometrically conjugate to a subshift of finite type on r symbols where r ≥ 4. However, these subshifts on r symbols are all topologically conjugate to the full shift on three symbols. The p-adic Gibbs measures of the same model for the prime numbers p=2,3 and the corresponding Potts-Bethe mapping are also discussed. On the other hand, for 0< |θ -1|_p< |q|_p < 1, we remark that the Potts-Bethe mapping is not chaotic when p=3 and p≡ 2 (mod 3) and we could not conclude the vastness of the set of the periodic p-adic Gibbs measures. In a forthcoming paper with the same title, we will treat the case 0< |q|_p ≤ |θ -1|_p < 1 for all prime numbers p.

The stopping power and energy straggling of the energetic C and O ions in polyimide

NASA Astrophysics Data System (ADS)

Mikšová, R.; Macková, A.; Slepička, P.

2016-03-01

The stopping power and energy straggling of 12Cn+ and 16On+ heavy ions in the energy range 5.3-8.0 MeV in 8 μm thick polyimide (PI) foil were measured by means of an indirect transmission method using a half-covered a PIPS detector. Ions scattered from thin gold layer, under the scattering angle 150° were detected and the spectrum of ions penetrating the PI foil and without foil was recorded. The values of the experimentally determined stopping powers were compared to the calculated data by SRIM-2013 and MSTAR codes. Measured data were in good agreement with data calculated by SRIM-2013, especially for C ions was observed better agreement than for O ions. The energy straggling was determined and compared to those calculated by using Bohr's, Bethe-Livingston and Yang models. The measured energy straggling values in the PI foil was corrected for foil roughness and thickness inhomogeneity determined from AFM. Bethe-Livingston predicting formula has been modified to make it appropriate for thicker targets. The energy straggling determined in our experiment was obtained higher than Bohr's predicted value; the predictions by Yang are in good agreement with our experiment. Bethe-Livingston formulation of the energy straggling shows better agreement with the experimental data after the modified formula implementation which assumes that the thick target was consisted to be composed of n-number of thin layers. Influence of the charge-exchange phenomena to the energy straggling of C and O ions in PI was discussed.

Reforming the American Military Officer Personnel System

DTIC Science & Technology

2015-12-02

Lamping Lewis, Henry Leonard, Julia Pollak, Christopher Guo and Bernard Rostker, Tour Lengths, Permanent Changes of Station, and Alternatives for...Raymond E. Conley, Stephanie Young, William A. Williams, Jeffrey Engstrom, Barbara Bicksler, Sara Beth Elson, Joseph Jenkins , Lianne Kennedy

Strong Coupling Continuum QCD

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

Pennington, M. R.

2011-05-23

The Schwinger-Dyson, Bethe-Salpeter system of equations are the link between coloured quarks and gluons, and colourless hadrons and their properties. This talk reviews some aspects of these studies from the infrared behaviour of ghosts to the prediction of electromagnetic form-factors.

Strong Coupling Continuum QCD

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

Michael Pennington

2011-05-01

The Schwinger-Dyson, Bethe-Salpeter system of equations are the link between coloured quarks and gluons, and colourless hadrons and their properties. This talk reviews some aspects of these studies from the infrared behaviour of ghosts to the prediction of electromagnetic form-factors.

Technical Note: On the calculation of stopping-power ratio for stoichiometric calibration in proton therapy

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

Ödén, Jakob; Zimmerman, Jens; Nowik, Patrik

2015-09-15

Purpose: The quantitative effects of assumptions made in the calculation of stopping-power ratios (SPRs) are investigated, for stoichiometric CT calibration in proton therapy. The assumptions investigated include the use of the Bethe formula without correction terms, Bragg additivity, the choice of I-value for water, and the data source for elemental I-values. Methods: The predictions of the Bethe formula for SPR (no correction terms) were validated against more sophisticated calculations using the SRIM software package for 72 human tissues. A stoichiometric calibration was then performed at our hospital. SPR was calculated for the human tissues using either the assumption of simplemore » Bragg additivity or the Seltzer-Berger rule (as used in ICRU Reports 37 and 49). In each case, the calculation was performed twice: First, by assuming the I-value of water was an experimentally based value of 78 eV (value proposed in Errata and Addenda for ICRU Report 73) and second, by recalculating the I-value theoretically. The discrepancy between predictions using ICRU elemental I-values and the commonly used tables of Janni was also investigated. Results: Errors due to neglecting the correction terms to the Bethe formula were calculated at less than 0.1% for biological tissues. Discrepancies greater than 1%, however, were estimated due to departures from simple Bragg additivity when a fixed I-value for water was imposed. When the I-value for water was calculated in a consistent manner to that for tissue, this disagreement was substantially reduced. The difference between SPR predictions when using Janni’s or ICRU tables for I-values was up to 1.6%. Experimental data used for materials of relevance to proton therapy suggest that the ICRU-derived values provide somewhat more accurate results (root-mean-square-error: 0.8% versus 1.6%). Conclusions: The conclusions from this study are that (1) the Bethe formula can be safely used for SPR calculations without correction terms; (2) simple Bragg additivity can be reasonably assumed for compound materials; (3) if simple Bragg additivity is assumed, then the I-value for water should be calculated in a consistent manner to that of the tissue of interest (rather than using an experimentally derived value); (4) the ICRU Report 37 I-values may provide a better agreement with experiment than Janni’s tables.« less

Nuclear Astrophysics Before 1957

NASA Astrophysics Data System (ADS)

Salpeter, Edwin E.

I discuss especially my summer with Willy Fowler at Kellogg Radiation Laboratory in 1951, where I did my `triple alpha' work. I also go back even earlier to Arthur Eddington and Hans Bethe. The 1953 summer school in Ann Arbor only gets a mention.

Paraprofessionals in Education Today.

ERIC Educational Resources Information Center

Gartner, Alan, Ed.; And Others

Included are articles on the Education Professions Development Act, an inside perspective (Don Davies); paraprofessionals in education for handicapped children (Mary-Beth Fafard, Musette El-Mohammed, Alan Gartner, Gina Schuster); paraprofessionals in preschool program, especially Project Head Start (A. Carla Drije); the paraprofessional in follow…

Missing energies at pair creation

NASA Technical Reports Server (NTRS)

El-Ela, A. A.; Hassan, S.; Bagge, E. R.

1985-01-01

Wilson cloud chamber measurements of the separated spectra of positrons and electrons produced by gamma quanta of 6.14 MeV differ considerably from the theoretically predicted spectra by BETHE and HEITLER, but are in good agreement with those of a modified theory of pair creation.

Making Team Differences Work

ERIC Educational Resources Information Center

Strathman, Beth

2015-01-01

Most district and school leaders understand that recruiting group members who have differing backgrounds, perspectives, talents, and personalities makes for good decision-making. Unfortunately, simply assembling a variety of top-notch individuals does not necessarily mean their talents and perspectives will be fully considered. Beth Strathman…

1. Historic American Buildings Survey EAST AND SOUTH ELEVATIONS BEFORE ...

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

1. Historic American Buildings Survey EAST AND SOUTH ELEVATIONS BEFORE ADDITION OF PORCH, ALTERATION OF WINDOWS From the Collection of the Title Insurance Company, SanDiego, Negative FEP - 1323 - Temple Beth Israel, 1502 Second Avenue, San Diego, San Diego County, CA

Strategies for Success

ERIC Educational Resources Information Center

Training, 2012

2012-01-01

"Training" magazine taps 2012 Training Top 125 winners and Top 10 Hall of Famers to provide their learning and development best practices in each issue. In this article, Jamie Leitch (American Infrastructure) and Mary Beth Alexander (The Economical Insurance Group) share strategies for tuition reimbursement and professional designations.

Policies for Managing Reductions in Military End Strength: Using Incentive Pays to Draw Down the Force

DTIC Science & Technology

2016-01-01

Michael G. Mattock, James Hosek, Beth J. Asch Policies for Managing Reductions in Military End Strength Using Incentive Pays to Draw Down the...5 Voluntary Separation Incentive and...Using Incentives to Draw Down the Force

Discrete geometric analysis of message passing algorithm on graphs

NASA Astrophysics Data System (ADS)

Watanabe, Yusuke

2010-04-01

We often encounter probability distributions given as unnormalized products of non-negative functions. The factorization structures are represented by hypergraphs called factor graphs. Such distributions appear in various fields, including statistics, artificial intelligence, statistical physics, error correcting codes, etc. Given such a distribution, computations of marginal distributions and the normalization constant are often required. However, they are computationally intractable because of their computational costs. One successful approximation method is Loopy Belief Propagation (LBP) algorithm. The focus of this thesis is an analysis of the LBP algorithm. If the factor graph is a tree, i.e. having no cycle, the algorithm gives the exact quantities. If the factor graph has cycles, however, the LBP algorithm does not give exact results and possibly exhibits oscillatory and non-convergent behaviors. The thematic question of this thesis is "How the behaviors of the LBP algorithm are affected by the discrete geometry of the factor graph?" The primary contribution of this thesis is the discovery of a formula that establishes the relation between the LBP, the Bethe free energy and the graph zeta function. This formula provides new techniques for analysis of the LBP algorithm, connecting properties of the graph and of the LBP and the Bethe free energy. We demonstrate applications of the techniques to several problems including (non) convexity of the Bethe free energy, the uniqueness and stability of the LBP fixed point. We also discuss the loop series initiated by Chertkov and Chernyak. The loop series is a subgraph expansion of the normalization constant, or partition function, and reflects the graph geometry. We investigate theoretical natures of the series. Moreover, we show a partial connection between the loop series and the graph zeta function.

Fast iterative solution of the Bethe-Salpeter eigenvalue problem using low-rank and QTT tensor approximation

NASA Astrophysics Data System (ADS)

Benner, Peter; Dolgov, Sergey; Khoromskaia, Venera; Khoromskij, Boris N.

2017-04-01

In this paper, we propose and study two approaches to approximate the solution of the Bethe-Salpeter equation (BSE) by using structured iterative eigenvalue solvers. Both approaches are based on the reduced basis method and low-rank factorizations of the generating matrices. We also propose to represent the static screen interaction part in the BSE matrix by a small active sub-block, with a size balancing the storage for rank-structured representations of other matrix blocks. We demonstrate by various numerical tests that the combination of the diagonal plus low-rank plus reduced-block approximation exhibits higher precision with low numerical cost, providing as well a distinct two-sided error estimate for the smallest eigenvalues of the Bethe-Salpeter operator. The complexity is reduced to O (Nb2) in the size of the atomic orbitals basis set, Nb, instead of the practically intractable O (Nb6) scaling for the direct diagonalization. In the second approach, we apply the quantized-TT (QTT) tensor representation to both, the long eigenvectors and the column vectors in the rank-structured BSE matrix blocks, and combine this with the ALS-type iteration in block QTT format. The QTT-rank of the matrix entities possesses almost the same magnitude as the number of occupied orbitals in the molecular systems, No

WE-D-BRF-05: Quantitative Dual-Energy CT Imaging for Proton Stopping Power Computation

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

Han, D; Williamson, J; Siebers, J

2014-06-15

Purpose: To extend the two-parameter separable basis-vector model (BVM) to estimation of proton stopping power from dual-energy CT (DECT) imaging. Methods: BVM assumes that the photon cross sections of any unknown material can be represented as a linear combination of the corresponding quantities for two bracketing basis materials. We show that both the electron density (ρe) and mean excitation energy (Iex) can be modeled by BVM, enabling stopping power to be estimated from the Bethe-Bloch equation. We have implemented an idealized post-processing dual energy imaging (pDECT) simulation consisting of monogenetic 45 keV and 80 keV scanning beams with polystyrene-water andmore » water-CaCl2 solution basis pairs for soft tissues and bony tissues, respectively. The coefficients of 24 standard ICRU tissue compositions were estimated by pDECT. The corresponding ρe, Iex, and stopping power tables were evaluated via BVM and compared to tabulated ICRU 44 reference values. Results: BVM-based pDECT was found to estimate ρe and Iex with average and maximum errors of 0.5% and 2%, respectively, for the 24 tissues. Proton stopping power values at 175 MeV, show average/maximum errors of 0.8%/1.4%. For adipose, muscle and bone, these errors result range prediction accuracies less than 1%. Conclusion: A new two-parameter separable DECT model (BVM) for estimating proton stopping power was developed. Compared to competing parametric fit DECT models, BVM has the comparable prediction accuracy without necessitating iterative solution of nonlinear equations or a sample-dependent empirical relationship between effective atomic number and Iex. Based on the proton BVM, an efficient iterative statistical DECT reconstruction model is under development.« less

78 FR 48672 - Environmental Impacts Statements;

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-09

... Bend Vegetation Management Project, Review Period Ends: 09/19/2013, Contact: Beth Peer 541-383- 4769... Supplement, USFS, ID, Salmon-Challis National Forest Travel Planning and OHV Designation Project, Comment... Mine Project, Comment Period Ends: 09/23/2013, Contact: Shiva Achet 575-234-5924 EIS No. 20130235...

75 FR 59704 - Office of Management; Performance Review Board Membership

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-28

... FURTHER INFORMATION CONTACT: Mary Beth Pultz, Director, Executive Resources Team, Human Resources Services... DEPARTMENT OF EDUCATION Office of Management; Performance Review Board Membership AGENCY... Department of Education for 2010 is composed of career and non-career senior executives. The PRB reviews and...

Managing Risk in Mobile Applications with Formal Security Policies

DTIC Science & Technology

2013-04-01

Alternatively, Breaux and Powers (2009) found the Business Process Modeling Notation ( BPMN ), a declarative language for describing business processes, to be...the Business Process Execution Language (BPEL), preferred as the candidate formal semantics for BPMN , only works for limited classes of BPMN models

Investigations of Naturalistic Decision Making and the Recognition-Primed Decision Model

DTIC Science & Technology

1990-07-01

major substantive contributions to the research: Beth W. Crandall, Marvin L. Thordsen, Janet Taynor, and Christopher Brezovic. We wish to thank our...Eyewitness menary enhancement in the police interview: Cognitive retrieval mnemonics versus hypnosis . Journal of Alied Psychology, 70, 2, 401-412

76 FR 50726 - Agency Information Collection Activities; Proposed Collection; Comment Request; EPA Strategic...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-16

... Activities; Proposed Collection; Comment Request; EPA Strategic Plan Information on Source Water Protection... submitting comments. E-mail: [email protected] . Mail: Water Docket, Environmental Protection Agency, EPA.../epahome/dockets.htm . FOR FURTHER INFORMATION CONTACT: Beth Hall, Drinking Water Protection Division...

Exact solution of the relativistic quantum Toda chain

NASA Astrophysics Data System (ADS)

Zhang, Xin; Cao, Junpeng; Yang, Wen-Li; Shi, Kangjie; Wang, Yupeng

2017-03-01

The relativistic quantum Toda chain model is studied with the generalized algebraic Bethe Ansatz method. By employing a set of local gauge transformations, proper local vacuum states can be obtained for this model. The exact spectrum and eigenstates of the model are thus constructed simultaneously.

Approach to calculation of mass spectra and two-photon decays of c c¯ mesons in the framework of Bethe-Salpeter equation

NASA Astrophysics Data System (ADS)

Bhatnagar, Shashank; Alemu, Lmenew

2018-02-01

In this work we calculate the mass spectra of charmonium for 1 P ,…,4 P states of 0++ and 1++, for 1 S ,…,5 S states of 0-+, and for 1 S ,…,4 D states of 1- along with the two-photon decay widths of the ground and first excited states of 0++ quarkonia for the process O++→γ γ in the framework of a QCD-motivated Bethe-Salpeter equation (BSE). In this 4 ×4 BSE framework, the coupled Salpeter equations are first shown to decouple for the confining part of the interaction (under the heavy-quark approximation) and are analytically solved, and later the one-gluon-exchange interaction is perturbatively incorporated, leading to mass spectral equations for various quarkonia. The analytic forms of wave functions obtained are used for the calculation of the two-photon decay widths of χc 0. Our results are in reasonable agreement with data (where available) and other models.

Experimental observation of Bethe strings

NASA Astrophysics Data System (ADS)

Wang, Zhe; Wu, Jianda; Yang, Wang; Bera, Anup Kumar; Kamenskyi, Dmytro; Islam, A. T. M. Nazmul; Xu, Shenglong; Law, Joseph Matthew; Lake, Bella; Wu, Congjun; Loidl, Alois

2018-02-01

Almost a century ago, string states—complex bound states of magnetic excitations—were predicted to exist in one-dimensional quantum magnets. However, despite many theoretical studies, the experimental realization and identification of string states in a condensed-matter system have yet to be achieved. Here we use high-resolution terahertz spectroscopy to resolve string states in the antiferromagnetic Heisenberg-Ising chain SrCo2V2O8 in strong longitudinal magnetic fields. In the field-induced quantum-critical regime, we identify strings and fractional magnetic excitations that are accurately described by the Bethe ansatz. Close to quantum criticality, the string excitations govern the quantum spin dynamics, whereas the fractional excitations, which are dominant at low energies, reflect the antiferromagnetic quantum fluctuations. Today, Bethe’s result is important not only in the field of quantum magnetism but also more broadly, including in the study of cold atoms and in string theory; hence, we anticipate that our work will shed light on the study of complex many-body systems in general.

Accurate X-Ray Spectral Predictions: An Advanced Self-Consistent-Field Approach Inspired by Many-Body Perturbation Theory

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

Liang, Yufeng; Vinson, John; Pemmaraju, Sri

Constrained-occupancy delta-self-consistent-field (ΔSCF) methods and many-body perturbation theories (MBPT) are two strategies for obtaining electronic excitations from first principles. Using the two distinct approaches, we study the O 1s core excitations that have become increasingly important for characterizing transition-metal oxides and understanding strong electronic correlation. The ΔSCF approach, in its current single-particle form, systematically underestimates the pre-edge intensity for chosen oxides, despite its success in weakly correlated systems. By contrast, the Bethe-Salpeter equation within MBPT predicts much better line shapes. This motivates one to reexamine the many-electron dynamics of x-ray excitations. We find that the single-particle ΔSCF approach can bemore » rectified by explicitly calculating many-electron transition amplitudes, producing x-ray spectra in excellent agreement with experiments. This study paves the way to accurately predict x-ray near-edge spectral fingerprints for physics and materials science beyond the Bethe-Salpether equation.« less

Relocking of intrinsic angular momenta in collisions of diatoms with ions: Capture of H2(j = 0,1) by H2+

NASA Astrophysics Data System (ADS)

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

2016-12-01

Rate coefficients for capture of H2(j = 0,1) by H2+ are calculated in perturbed rotor approximation, i.e., at collision energies considerably lower than Bhc (where B denotes the rotational constant of H2). The results are compared with the results from an axially nonadiabatic channel (ANC) approach, the latter providing a very good approximation from the low-temperature Bethe-Wigner to the high temperature Langevin limit. The classical ANC approximation performs satisfactorily at temperatures above 0.1 K. At 0.1 K, the rate coefficient for j =1 is about 25% higher than that for j = 0 while the latter is close to the Langevin rate coefficient. The Bethe-Wigner limit of the rate coefficient for j = 1 is about twice that for j = 0. The analysis of the relocking of the intrinsic angular momentum of H2 during the course of the collision illustrates the significance of relocking in capture dynamics in general.

The {{\\rm{D}}\\bar{{\\rm{D}}}}^{{\\rm{* }}} interaction with isospin zero in an extended hidden gauge symmetry approach

NASA Astrophysics Data System (ADS)

Sun, Bao-Xi; Wan, Da-Ming; Zhao, Si-Yu

2018-05-01

The {{{D}}\\bar{{{D}}}}{{* }} interaction via a ρ or ω exchange is constructed within an extended hidden gauge symmetry approach, where the strange quark is replaced by the charm quark in the SU(3) flavor space. With this {{{D}}\\bar{{{D}}}}{{* }} interaction, a bound state slightly lower than the {{{D}}\\bar{{{D}}}}{{* }} threshold is generated dynamically in the isospin zero sector by solving the Bethe-Salpeter equation in the coupled-channel approximation, which might correspond to the X(3872) particle announced by many collaborations. This formulism is also used to study the {{{B}}\\bar{{{B}}}}{{* }} interaction, and a {{{B}}\\bar{{{B}}}}{{* }} bound state with isospin zero is generated dynamically, which has no counterpart listed in the review of the Particle Data Group. Furthermore, the one-pion exchange between the D meson and the {\\bar{{{D}}}}{{* }} is analyzed precisely, and we do not think the one-pion exchange potential need be considered when the Bethe-Salpeter equation is solved.

Spin Hartree-Fock approach to studying quantum Heisenberg antiferromagnets in low dimensions

NASA Astrophysics Data System (ADS)

Werth, A.; Kopietz, P.; Tsyplyatyev, O.

2018-05-01

We construct a new mean-field theory for a quantum (spin-1/2) Heisenberg antiferromagnet in one (1D) and two (2D) dimensions using a Hartree-Fock decoupling of the four-point correlation functions. We show that the solution to the self-consistency equations based on two-point correlation functions does not produce any unphysical finite-temperature phase transition, in accord with the Mermin-Wagner theorem, unlike the common approach based on the mean-field equation for the order parameter. The next-neighbor spin-spin correlation functions, calculated within this approach, reproduce closely the strong renormalization by quantum fluctuations obtained via a Bethe ansatz in 1D and a small renormalization of the classical antiferromagnetic state in 2D. The heat capacity approximates with reasonable accuracy the full Bethe ansatz result at all temperatures in 1D. In 2D, we obtain a reduction of the peak height in the heat capacity at a finite temperature that is accessible by high-order 1 /T expansions.

Optical properties of body-centered tetragonal C4: Insights from many-body perturbation and time-dependent density functional theories

NASA Astrophysics Data System (ADS)

Tarighi Ahmadpour, Mahdi; Rostamnejadi, Ali; Hashemifar, S. Javad

2018-04-01

We study the electronic structure and optical properties of a body-centered tetragonal phase of carbon (bct-C4) within the framework of time-dependent density functional theory and Bethe-Salpeter equation. The results indicate that the optical properties of bct-C4 are strongly affected by the electron-hole interaction. It is demonstrated that the long-range corrected exchange-correlation kernels could fairly reproduce the Bethe-Salpeter equation results. The effective carrier number reveals that at energies above 30 eV, the excitonic effects are not dominant any more and that the optical transitions originate mainly from electronic excitations. The emerged peaks in the calculated electron energy loss spectra are discussed in terms of plasmon excitations and interband transitions. The results of the research indicate that bct-C4 is an indirect wide-band-gap semiconductor, which is transparent in the visible region and opaque in the ultraviolet spectral range.

Solution of the classical Yang-Baxter equation with an exotic symmetry, and integrability of a multi-species boson tunnelling model

NASA Astrophysics Data System (ADS)

Links, Jon

2017-03-01

Solutions of the classical Yang-Baxter equation provide a systematic method to construct integrable quantum systems in an algebraic manner. A Lie algebra can be associated with any solution of the classical Yang-Baxter equation, from which commuting transfer matrices may be constructed. This procedure is reviewed, specifically for solutions without skew-symmetry. A particular solution with an exotic symmetry is identified, which is not obtained as a limiting expansion of the usual Yang-Baxter equation. This solution facilitates the construction of commuting transfer matrices which will be used to establish the integrability of a multi-species boson tunnelling model. The model generalises the well-known two-site Bose-Hubbard model, to which it reduces in the one-species limit. Due to the lack of an apparent reference state, application of the algebraic Bethe Ansatz to solve the model is prohibitive. Instead, the Bethe Ansatz solution is obtained by the use of operator identities and tensor product decompositions.

Thermodynamics of Inozemtsev's elliptic spin chain

NASA Astrophysics Data System (ADS)

Klabbers, Rob

2016-06-01

We study the thermodynamic behaviour of Inozemtsev's long-range elliptic spin chain using the Bethe ansatz equations describing the spectrum of the model in the infinite-length limit. We classify all solutions of these equations in that limit and argue which of these solutions determine the spectrum in the thermodynamic limit. Interestingly, some of the solutions are not selfconjugate, which puts the model in sharp contrast to one of the model's limiting cases, the Heisenberg XXX spin chain. Invoking the string hypothesis we derive the thermodynamic Bethe ansatz equations (TBA-equations) from which we determine the Helmholtz free energy in thermodynamic equilibrium and derive the associated Y-system. We corroborate our results by comparing numerical solutions of the TBA-equations to a direct computation of the free energy for the finite-length hamiltonian. In addition we confirm numerically the interesting conjecture put forward by Finkel and González-López that the original and supersymmetric versions of Inozemtsev's elliptic spin chain are equivalent in the thermodynamic limit.

Singular eigenstates in the even(odd) length Heisenberg spin chain

NASA Astrophysics Data System (ADS)

Ranjan Giri, Pulak; Deguchi, Tetsuo

2015-05-01

We study the implications of the regularization for the singular solutions on the even(odd) length spin-1/2 XXX chains in some specific down-spin sectors. In particular, the analytic expressions of the Bethe eigenstates for three down-spin sector have been obtained along with their numerical forms in some fixed length chains. For an even-length chain if the singular solutions \\{{{λ }α }\\} are invariant under the sign changes of their rapidities \\{{{λ }α }\\}=\\{-{{λ }α }\\}, then the Bethe ansatz equations are reduced to a system of (M-2)/2((M-3)/2) equations in an even (odd) down-spin sector. For an odd N length chain in the three down-spin sector, it has been analytically shown that there exist singular solutions in any finite length of the spin chain of the form N=3(2k+1) with k=1,2,3,\\cdots . It is also shown that there exist no singular solutions in the four down-spin sector for some odd-length spin-1/2 XXX chains.

Dynamics of Fermionic Impurity in One Dimension

NASA Astrophysics Data System (ADS)

Guan, Huijie; Andrei, Natan

2014-03-01

We study the dynamics of a fermionic impurity propagating in a one dimensional infinite line. The system is described by the Gaudin-Yang Model and is exactly solvable by the Nested Bethe Ansatz. Starting from a generic initial state, we obtain the time evolution of the wavefunction by the Yudson Approach in which we expand the initial state with the Nested Bethe Ansatz solutions. One situation that we are interested in is where, initially, the impurity is embedded in host fermions with a lattice configuration and one remove the periodic potential at time zero. We calculate the density profile and correlation functions at a later time. Another situation is to shoot an impurity into a cloud of fermions and calculate the probability for it to pass through. While the repulsive case has been studied already[1], we extend it to the attractive case and study the role of bound states in the evolution. We are also interested in boson impurity problem, where not only impurity interacts with host particles, all host particles interact with each other.

Accurate X-Ray Spectral Predictions: An Advanced Self-Consistent-Field Approach Inspired by Many-Body Perturbation Theory

DOE PAGES

Liang, Yufeng; Vinson, John; Pemmaraju, Sri; ...

2017-03-03

Constrained-occupancy delta-self-consistent-field (ΔSCF) methods and many-body perturbation theories (MBPT) are two strategies for obtaining electronic excitations from first principles. Using the two distinct approaches, we study the O 1s core excitations that have become increasingly important for characterizing transition-metal oxides and understanding strong electronic correlation. The ΔSCF approach, in its current single-particle form, systematically underestimates the pre-edge intensity for chosen oxides, despite its success in weakly correlated systems. By contrast, the Bethe-Salpeter equation within MBPT predicts much better line shapes. This motivates one to reexamine the many-electron dynamics of x-ray excitations. We find that the single-particle ΔSCF approach can bemore » rectified by explicitly calculating many-electron transition amplitudes, producing x-ray spectra in excellent agreement with experiments. This study paves the way to accurately predict x-ray near-edge spectral fingerprints for physics and materials science beyond the Bethe-Salpether equation.« less

Bond Dilution Effects on Bethe Lattice the Spin-1 Blume-Capel Model

NASA Astrophysics Data System (ADS)

Albayrak, Erhan

2017-09-01

The bond dilution effects are investigated for the spin-1 Blume-Capel model on the Bethe lattice by using the exact recursion relations. The bilinear interaction parameter is either turned on ferromagnetically with probability p or turned off with probability 1 - p between the nearest-neighbor spins. The thermal variations of the order-parameters are studied in detail to obtain the phase diagrams on the possible planes spanned by the temperature (T), probability (p) and crystal field (D) for the coordination numbers q = 3, 4, and 6. The lines of the second-order phase transitions, Tc-lines, combined with the first-order ones, Tt-lines, at the tricritical points (TCP) are always found for any p and q on the (T, D)-planes. It is also found that the model gives only Tc-lines, Tc-lines combined with the Tt-lines at the TCP’s and only Tt-lines with the consecutively decreasing values of D on the (T, p)-planes for all q.

G W (Γ ) method without the Bethe-Salpeter equation for photoabsorption energies of spin-polarized systems

NASA Astrophysics Data System (ADS)

Isobe, Tomoharu; Kuwahara, Riichi; Ohno, Kaoru

2018-06-01

The one-shot G W method, beginning with the local density approximation (LDA), enables one to calculate photoemission and inverse photoemission spectra. In order to calculate photoabsorption spectra, one had to additionally solve the Bethe-Salpeter equation (BSE) for the two-particle (electron-hole) Green's function, which doubly induces evaluation errors. It has been recently reported that the G W +BSE method significantly underestimates the experimental photoabsorption energies (PAEs) of small molecules. In order to avoid these problems, we propose to apply the G W (Γ ) method not to the neutral ground state but to the cationic state to calculate PAEs without solving the BSE, which allows a rigorous one-to-one correspondence between the photoabsorption peak and the "extended" quasiparticle level. We applied the self-consistent linearized G W Γ method including the vertex correction Γ to our method, and found that this method gives the PAEs of B, Na3, and Li3 to within 0.1 eV accuracy.

Accurate X-Ray Spectral Predictions: An Advanced Self-Consistent-Field Approach Inspired by Many-Body Perturbation Theory.

PubMed

Liang, Yufeng; Vinson, John; Pemmaraju, Sri; Drisdell, Walter S; Shirley, Eric L; Prendergast, David

2017-03-03

Constrained-occupancy delta-self-consistent-field (ΔSCF) methods and many-body perturbation theories (MBPT) are two strategies for obtaining electronic excitations from first principles. Using the two distinct approaches, we study the O 1s core excitations that have become increasingly important for characterizing transition-metal oxides and understanding strong electronic correlation. The ΔSCF approach, in its current single-particle form, systematically underestimates the pre-edge intensity for chosen oxides, despite its success in weakly correlated systems. By contrast, the Bethe-Salpeter equation within MBPT predicts much better line shapes. This motivates one to reexamine the many-electron dynamics of x-ray excitations. We find that the single-particle ΔSCF approach can be rectified by explicitly calculating many-electron transition amplitudes, producing x-ray spectra in excellent agreement with experiments. This study paves the way to accurately predict x-ray near-edge spectral fingerprints for physics and materials science beyond the Bethe-Salpether equation.

Solution of semi-flexible self-avoiding trails on a Husimi lattice built with squares

NASA Astrophysics Data System (ADS)

Oliveira, Tiago J.; Dantas, Wellington G.; Prellberg, Thomas; Stilck, Jürgen F.

2018-02-01

We study a model of semi-flexible self-avoiding trails, where the lattice paths are constrained to visit each lattice edge at most once, with configurations weighted by the number of collisions, crossings and bends, on a Husimi lattice built with squares. We find a rich phase diagram with five phases: a non-polymerised phase (NP), low density (P1) and high density (P2) polymerised phases, and, for sufficiently large stiffness, two additional anisotropic (nematic) (AN1 and AN2) polymerised phases within the P1 phase. Moreover, the AN1 phase which shows a broken symmetry with a preferential direction, is separated from the P1 phase by the other nematic AN2 phase. Although this scenario is similar to what was found in our previous calculation on the Bethe lattice, where the AN-P1 transition was discontinuous and critical, the presence of the additional nematic phase between them introduces a qualitative difference. Other details of the phase diagram are that a line of tri-critical points may separate the P1-P2 transition surface into a continuous and a discontinuous portion, and that the same may happen at the NP-P1 transition surface, details of which depend on whether crossings are allowed or forbidden. A critical end-point line is also found in the phase diagram.

Reliability of the one-crossing approximation in describing the Mott transition

NASA Astrophysics Data System (ADS)

Vildosola, V.; Pourovskii, L. V.; Manuel, L. O.; Roura-Bas, P.

2015-12-01

We assess the reliability of the one-crossing approximation (OCA) approach in a quantitative description of the Mott transition in the framework of the dynamical mean field theory (DMFT). The OCA approach has been applied in conjunction with DMFT to a number of heavy-fermion, actinide, transition metal compounds and nanoscale systems. However, several recent studies in the framework of impurity models pointed out serious deficiencies of OCA and raised questions regarding its reliability. Here we consider a single band Hubbard model on the Bethe lattice at finite temperatures and compare the results of OCA to those of a numerically exact quantum Monte Carlo (QMC) method. The temperature-local repulsion U phase diagram for the particle-hole symmetric case obtained by OCA is in good agreement with that of QMC, with the metal-insulator transition captured very well. We find, however, that the insulator to metal transition is shifted to higher values of U and, simultaneously, correlations in the metallic phase are significantly overestimated. This counter-intuitive behaviour is due to simultaneous underestimations of the Kondo scale in the metallic phase and the size of the insulating gap. We trace the underestimation of the insulating gap to that of the second moment of the high-frequency expansion of the impurity spectral density. Calculations of the system away from the particle-hole symmetric case are also presented and discussed.

Teaching With Historic Places.

ERIC Educational Resources Information Center

Greenberg, Ronald M., Ed.

1993-01-01

Designed for social studies educators, this theme issue presents 11 articles about historic places that feature a variety of ideas for elementary and secondary lesson plans, curricula, and program development. The articles are: (1) "Where did History Happen?" (Beth M. Boland); (2) "Creating a Partnership" (Carol D. Shull); (3)…

Photocopy of photograph (original negative in possession of LSA Associates, ...

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

Photocopy of photograph (original negative in possession of LSA Associates, Irvine, California) Beth Padon, photographer, 1985 WEST (REAR) IN RELATION TO GARAGE, LOOKING NORTH - Irvine Ranch Agricultural Headquarters, Boyd Tenant House, Southeast of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

Sixteen Textbook Authors Respond.

ERIC Educational Resources Information Center

Hewitt, John P.; And Others

1988-01-01

The articles on textbook publication written by Sheryl Fullerton and Franklin C. Graham were responded to by: John Hewitt, Henry Tischler, George Ritzer, Paul Baker, Erich Goode, D. Stanley Eitzen, Jon Shepard, Richard Schaefer, Caroline Persell, Beth Hess, Paul Zopf, Jr., Jeanne Ballantine, Duane Monette, Mary Ann Lamanna, John Macionis, and…

Tuning in to Young Viewers: Social Science Perspectives on Television.

ERIC Educational Resources Information Center

MacBeth, Tannis M., Ed.

Research indicates that children are especially vulnerable to the effects of television viewing. Taking a psychological, social-science perspective, this book explores how television viewing affects children. Chapter 1, "Introduction," (MacBeth) discusses the issues involved, how researchers go about studying media effects, whether television…

A NOVEL EFFECT OF DIOXIN: EXPOSURE DURING PREGNANCY SEVERELY IMPAIRS MAMMARY GLAND DIFFERENTIATION

EPA Science Inventory

A novel effect of dioxin: Exposure during pregnancy severely impairs mammary gland differentiation.
Beth A. Vorderstrasse1, Suzanne E. Fenton2, Andrea A. Bohn3, Jennifer A. Cundiff1, and B. Paige Lawrence1,3,4 1Department of Pharmaceutical Sciences, Washington State Universi...

The Law, Digitally Speaking

ERIC Educational Resources Information Center

Chronicle of Higher Education, 2008

2008-01-01

As new technologies emerge on campuses, how can colleges avoid legal land mines? What are the areas of greatest risk, and how should higher-education leaders deal with them? In this article, three experts offered their advice at the Technology Forum: Beth Cate, associate general counsel at Indiana University, on data privacy and security; Steven…

Integral Nursing: An Emerging Framework for Engaging the Evolution of the Profession.

ERIC Educational Resources Information Center

Fiandt, Kathryn; Forman, John; Megel, Mary Erickson; Pakieser, Ruth A.; Burge, Stephanie

2003-01-01

Proposes the Integral Nursing framework, which combines Wilber's All-Quadrant/All-Level model, a heuristic device to organize human experience, and the Spiral Dynamics model of human development organized around value memes or cultural units of information. Includes commentary by Beth L. Rodgers. (Contains 17 references.) (JOW)

Design and Modeling of a Compton-Suppressed Phoswich Detector for Radioxenon Monitoring

DTIC Science & Technology

2010-09-01

radioisotopes. There are three boxed areas (in the absence of any radon daughters ) from which the concentration of four xenon radioisotopes can be...The high-energy gamma-rays could originate from either external or internal (from radon daughters or radioxenon itself in the gas sample) gamma-ray

75 FR 2158 - Palmyra Atoll National Wildlife Refuge, U.S. Pacific Island Territory

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-14

... migratory birds, coral reefs, and threatened and endangered species in their natural setting. Palmyra Atoll..., (808) 792-9586. U.S. Mail: Beth Flint, Acting Project Leader, Pacific Reefs National Wildlife Refuge..., Pacific Reefs National Wildlife Refuge Complex, phone (808) 792-9553. SUPPLEMENTARY INFORMATION: Refuge...

Social Security: The Notch Issue.

DTIC Science & Technology

1988-03-24

the Exact Match Study, see Beth Kilss, Fritz Scheuren, Fay Aziz, and Linda DelBane, "The 1973 CPS-IRS-SSA Exact Match Study: Past, Present and Future...34 inPolicy Analysis with Social Security Research Files, Proceedings, SSA, 1978. 2For more discussion of the project, see Haber (1985) and, in the

Adult Learning Matters

ERIC Educational Resources Information Center

Adults Learning, 2009

2009-01-01

The Campaigning Alliance for Lifelong Learning is to lobby parliament for the restoration of the 1.5 million adult learning places lost over the past two years. The campaign has attracted supporters from an astonishingly wide range of backgrounds. In this article, Gordon Marsden, Caroline Biggins, Beth Walker, Mike Chaney, Peter Davies, Sian…

The Harmony Specialist

ERIC Educational Resources Information Center

Olson, Catherine Applefeld

2008-01-01

This article profiles Beth Gilbert, a veteran Arizona string teacher who finds inspiration in teamwork--and her students. Growing up in Ohio, Gilbert enjoyed participating in her high school orchestra. Nevertheless she entered the University of Arizona as a marine biology major, choosing a field of study that she had planned to parlay into a…

Secret Destinations

ERIC Educational Resources Information Center

Buss, David

2008-01-01

"All journeys have secret destinations of which the traveller is unaware" (Martin Buber). All learning results in learning outcomes of some form, planned or otherwise, but the term is now widely used to refer only to those learning outcomes that predetermine what those outcomes will be--the "intended" or "specified" learning outcomes of the…

2011 Women in Defense (WID) National Fall Conference

DTIC Science & Technology

2011-10-19

UCLA. She is also a graduate of the UCLA Executive Management Course and the University of Chicago Business Leadership Program. A member of the Air...Supercircuits Ms. Beth A. Shepard -Savery Cox Communications Hampton Roads, LLC Ms. Erin B. Sheppard McKenna Long & Aldridge, LLP Ms. Heidi L Shyu

2. Historic American Buildings Survey Copy by Bert Shankland, Photographer ...

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

2. Historic American Buildings Survey Copy by Bert Shankland, Photographer August 20, 1974 EAST AND SOUTH ELEVATION AFTER ADDITION OF PORCH, ALTERATION OF WINDOWS Fromthe Collection of the San Diego Historical Society, Serra Museum, San Diego - Temple Beth Israel, 1502 Second Avenue, San Diego, San Diego County, CA

76 FR 9028 - Training Program for Regulatory Project Managers; Information Available to Industry

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-16

... pharmaceutical companies interested in participating in this program to contact CDER. DATES: Pharmaceutical companies may submit proposed agendas to the Agency by April 18, 2011. FOR FURTHER INFORMATION CONTACT: Beth...-Miller (see DATES and FOR FURTHER INFORMATION CONTACT). Dated: February 9, 2011. Leslie Kux, Acting...

Recruiting Youth in the College Market: Current Practices and Future Policy Options.

ERIC Educational Resources Information Center

Kilburn, M. Rebecca, Ed.; Asch, Beth J., Ed.

This publication explores the enlistment potential of college-market youth by examining the characteristics of the college-market population and the implications of these characteristics for designing effective recruiting policies. Chapter 1, "Introduction: Trends and Theoretical Considerations" (M. Rebecca Kilburn, Beth J. Asch),…

77 FR 5840 - Notice of Inventory Completion: Kingman Museum, Incorporated, Battle Creek, MI; Correction

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-06

... DEPARTMENT OF THE INTERIOR National Park Service Notice of Inventory Completion: Kingman Museum... contact the Kingman Museum, Incorporated at the address below by March 7, 2012. ADDRESSES: Beth Yahne, Kingman Museum, Inc., 175 Limit Street, Battle Creek, MI 49037, telephone (269) 965-5117. SUPPLEMENTARY...

Platelets Orchestrate Remote Tissue Damage After Mesenteric Ischemia-Reperfusion

DTIC Science & Technology

2012-02-02

Medicine , Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave., CLS-928, Boston, MA 02115 (e-mail: gtsokos@bidmc.harvard.edu). Am...Guikema BJ, Fritzinger DC, Vogel CW, Stahl GL. Humanized cobra venom factor decreases myocardial ischemia-reperfu- sion injury. Mol Immunol 47: 506–510

Photoeffect cross sections of some rare-earth elements at 145.4 keV

NASA Astrophysics Data System (ADS)

Umesh, T. K.; Ranganathaiah, C.; Sanjeevaiah, B.

1985-08-01

Total attenuation cross sections in the elements La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, and Er were derived from the measured total cross sections of their simple oxide compounds, by employing the mixture rule at 145.4-keV photon energy. The compound cross sections have been measured by performing transmission experiments in a good geometry setup. From the derived total cross sections of elements, photoeffect cross sections have been obtained by subtracting the theoretical scattering cross sections. A good agreement is observed between the present data of photoeffect cross sections and Scofield's theoretical data.

Integrable open spin chains from flavored ABJM theory

NASA Astrophysics Data System (ADS)

Bai, Nan; Chen, Hui-Huang; He, Song; Wu, Jun-Bao; Yang, Wen-Li; Zhu, Meng-Qi

2017-08-01

We compute the two-loop anomalous dimension matrix in the scalar sector of planar N=3 flavored ABJM theory. Using coordinate Bethe ansatz, we obtain the reflection matrices and confirm that the boundary Yang-Baxter equations are satisfied. This establishes the integrability of this theory in the scalar sector at the two-loop order.

Effective Teaching of Reading: Research and Practice.

ERIC Educational Resources Information Center

Hoffman, James V., Ed.

Distilling and interpreting past and current research on the effective teaching of reading is the focus of this volume. The titles and authors are as follows: "Research in Effective Teaching: An Overview of Its Development" (William H. Rupley, Beth S. Wise, and John W. Logan); "Process-Product Research on Effective Teaching: A Primer for a…

Very Large Scale Distributed Information Processing Systems

DTIC Science & Technology

1991-09-27

USENIX Conference Proceedings, pp. 31-43. USENIX, February 1988. [KLA90] Michael L. Kazar, Bruce W. Leverett, Owen T. Anderson, Vasilis Apos- tolides, Beth...will be selected if cost is the curlcron Iorsleettin- IfFigure 2 R DistribUted Database lSgtam and its we combin the abolve two pit , n r-itcrr

75 FR 47595 - Science Advisory Board Staff Office; Notification of a Public Teleconference of the Clean Air...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-06

... Air Quality Standards--Second External Review Draft (June 2010). DATES: The teleconference will be... Standards--Second External Review Draft (June 2010). Background information on previous meetings and... Quality Standards--Second External Review Draft (June 2010) should be directed to Ms. Beth Hassett-Sipple...

President's Inaugural Address: We Call It School Nursing

ERIC Educational Resources Information Center

Mattey, Beth

2015-01-01

The incoming President of the National Association of School Nurses (NASN) traditionally outlines the theme for their presidency during their inaugural address. This address is given by incoming President of the NASN, Beth Mattey, who discusses previous themes that supported the mission of NASN, but changed every two years with each new president.…

Olfactory Deficits in MCI as Predictor of Improved Cognition on Donepezil

DTIC Science & Technology

2014-04-01

rivastigmine , and are being followed at the scheduled time-points as per the intent-to-treat principle employed in this study. The data obtained will be...the intent-to-treat principle, and in secondary analyses we will combine the data in patients who receive donepezil or galantamine or rivastigmine

Not Just to Teach But to Profess.

ERIC Educational Resources Information Center

Gibson, Claude L.

Discussion of the contribution of a particular course toward developing teacher competency raises the question: "Just what does one need to know to teach composition?" If a person were to take only one course, it would likely be "Composition for Teachers." In theory lie answers, so a suitable syllabus would include Beth Neman's "Teaching Students…

Culturally Inclusive Dance: Working with Chinese English Language Learners in the Dance Technique Classroom

ERIC Educational Resources Information Center

Johnson, Jamie A.

2018-01-01

Higher education is experiencing rapidly shifting demographics brought about by the expanding global economy. The influx of English Language Learners (ELLs) into U.S. dance classrooms is creating a shifting paradigm for students and instructors. According to Beth McMurtrie (2012), universities with increasing international enrollments recognize…

Living History

ERIC Educational Resources Information Center

Walsh, Mark

2005-01-01

John Tinker and Mary Beth Tinker are back in a classroom in their hometown, once again wearing black armbands and drawing attention to a war. Now in their 50s, the siblings are living symbols of constitutional rights for secondary school students. In 1965, they and a handful of others were suspended for wearing black armbands to their public…

75 FR 14594 - Environmental Impacts Statements; Notice of Availability

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-26

... Forest, Mono County, CA and Lyon, Douglas, and Mineral Counties, NV, Wait Period Ends: 04/26/2010.../ 2010, Contact: Douglas Gober, 208-476-4541. EIS No. 20100089, Draft EIS, STB, AK, Port MacKenzie Rail..., Richland, Benton County, WA, Comment Period Ends: 05/03/2010, Contact: Mary Beth Burandi, 888-829- 6347...

What Women Have Wrought.

ERIC Educational Resources Information Center

Murphy, Marjorie

1988-01-01

Reviews four books: "Counter Cultures" (Susan Porter Benson); "Once a Cigar Maker" (Patricia A. Cooper); "To Toil the Livelong Day" (Carol Groneman and Mary Beth North eds.); and "Gender at Work" (Ruth Milkman). The works examine cultural stereotypes about the nature of work and women and they attempt to dispel the ideas that women are less…

Opening Windows

ERIC Educational Resources Information Center

Bennett, Gayle

2011-01-01

Beth Kanter is working hard to get the word out about how best to get the word out. Kanter is CEO of Zoetica, which provides word-of-mouth communication services to nonprofits and socially conscious companies; a decade-long blogger on the topic of social media and nonprofits; and a popular conference speaker and trainer. She is also co-author of…

Developing Conceptual Understanding of Fractions with Year Five and Six Students

ERIC Educational Resources Information Center

Mills, Judith

2016-01-01

This paper presents findings from classroom observations of one teacher (Beth). It focusses on the development of conceptual understanding of fractions with her students, articulated in Kieren's sub-constructs (Kieren, 1980,1988), and Hansen's progressions (Hansen, 2005). The study covers three lessons within a six week unit. Findings from this…

Three Weeks with Hans Bethe

NASA Astrophysics Data System (ADS)

Adami, Christoph

Hans Bethe started visiting the Kellogg Radiation Laboratory, accompanied by Gerry Brown, every winter starting in the late eighties. My first visit to Kellogg was in 1991 as a final year graduate student. I returned in January of 1992, while a postdoc with Gerry Brown at SUNY Stony Brook, and this would be my first of many winter months spent in the company of both Hans and Gerry. The following notes are literally "mental downloads" that I wrote down every evening after leaving dinner with Hans, Gerry, and sometimes other invited guests that year. I indiscriminately wrote down everything that I could remember from that day, whether it seemed important or not, hoping to edit it later. In the end, I decided to keep the editing very minimal in order to preserve the original text's immediacy and spontaneity. Besides grammar and punctuation, a few facts that I remembered incorrectly were restored. I also added references and footnotes that add explanations where necessary. The following is a transcript of the conversations that took place between 20 January and 20 February, 1992.

Threshold singularities in a Fermi gas with attractive potential in one dimension

DOE PAGES

Schlottmann, P.; Zvyagin, A. A.

2015-01-15

We consider the one-dimensional gas of fermions with spin S interacting via an attractive δ-function potential using the Bethe Ansatz solution. In zero magnetic field the atoms form bound states of N=2S + 1 fermions, i.e. generalized Cooper states with each atom having a different spin component. For low energy excitations the system is a Luttinger liquid and is properly described by a conformal field theory with conformal charge c=1. The linear dispersion of a Luttinger liquid is asymptotically exact in the low-energy limit where the band curvature terms in the dispersion are irrelevant. For higher energy excitations, however, themore » spectral function displays deviations in the neighborhood of the single-particle (hole) energy, which can be described by an effective X-ray edge type model. Using the Bethe Ansatz solution we obtain expressions for the critical exponents for the single-particle (hole) Green’s function. This model can be relevant in the context of ultracold atoms with effective total spin S confined to an elongated optical trap.« less

GW/Bethe-Salpeter calculations for charged and model systems from real-space DFT

NASA Astrophysics Data System (ADS)

Strubbe, David A.

GW and Bethe-Salpeter (GW/BSE) calculations use mean-field input from density-functional theory (DFT) calculations to compute excited states of a condensed-matter system. Many parts of a GW/BSE calculation are efficiently performed in a plane-wave basis, and extensive effort has gone into optimizing and parallelizing plane-wave GW/BSE codes for large-scale computations. Most straightforwardly, plane-wave DFT can be used as a starting point, but real-space DFT is also an attractive starting point: it is systematically convergeable like plane waves, can take advantage of efficient domain parallelization for large systems, and is well suited physically for finite and especially charged systems. The flexibility of a real-space grid also allows convenient calculations on non-atomic model systems. I will discuss the interfacing of a real-space (TD)DFT code (Octopus, www.tddft.org/programs/octopus) with a plane-wave GW/BSE code (BerkeleyGW, www.berkeleygw.org), consider performance issues and accuracy, and present some applications to simple and paradigmatic systems that illuminate fundamental properties of these approximations in many-body perturbation theory.

Site-occupation embedding theory using Bethe ansatz local density approximations

NASA Astrophysics Data System (ADS)

Senjean, Bruno; Nakatani, Naoki; Tsuchiizu, Masahisa; Fromager, Emmanuel

2018-06-01

Site-occupation embedding theory (SOET) is an alternative formulation of density functional theory (DFT) for model Hamiltonians where the fully interacting Hubbard problem is mapped, in principle exactly, onto an impurity-interacting (rather than a noninteracting) one. It provides a rigorous framework for combining wave-function (or Green function)-based methods with DFT. In this work, exact expressions for the per-site energy and double occupation of the uniform Hubbard model are derived in the context of SOET. As readily seen from these derivations, the so-called bath contribution to the per-site correlation energy is, in addition to the latter, the key density functional quantity to model in SOET. Various approximations based on Bethe ansatz and perturbative solutions to the Hubbard and single-impurity Anderson models are constructed and tested on a one-dimensional ring. The self-consistent calculation of the embedded impurity wave function has been performed with the density-matrix renormalization group method. It has been shown that promising results are obtained in specific regimes of correlation and density. Possible further developments have been proposed in order to provide reliable embedding functionals and potentials.

The History and Impact of the CNO Cycles in Nuclear Astrophysics

NASA Astrophysics Data System (ADS)

Wiescher, Michael

2018-03-01

The carbon cycle, or Bethe-Weizsäcker cycle, plays an important role in astrophysics as one of the most important energy sources for quiescent and explosive hydrogen burning in stars. This paper presents the intellectual and historical background of the idea of the correlation between stellar energy production and the synthesis of the chemical elements in stars on the example of this cycle. In particular, it addresses the contributions of Carl Friedrich von Weizsäcker and Hans Bethe, who provided the first predictions of the carbon cycle. Further, the experimental verification of the predicted process as it developed over the following decades is discussed, as well as the extension of the initial carbon cycle to the carbon-nitrogen-oxygen (CNO) multi-cycles and the hot CNO cycles. This development emerged from the detailed experimental studies of the associated nuclear reactions over more than seven decades. Finally, the impact of the experimental and theoretical results on our present understanding of hydrogen burning in different stellar environments is presented, as well as the impact on our understanding of the chemical evolution of our universe.

Exciton self-trapping and Stark effect in the optical response of pentacene crystals from first principles

NASA Astrophysics Data System (ADS)

Strubbe, David A.; Sharifzadeh, Sahar; Neaton, Jeffrey B.; Louie, Steven G.

2012-02-01

Pentacene is a prototypical organic semiconductor with optoelectronic and photovoltaic applications. It is known that the lowest-energy singlet excitation has a Stokes shift between absorption and emission of about 0.14 eV, but the deformation associated with this self-trapped exciton remains unknown. We begin with a calculation of the optical properties via the first-principles GW/Bethe-Salpeter (BSE) theory [ML Tiago, JE Northrup, and SG Louie, Phys. Rev. B 67, 115212 (2003); S Sharifzadeh, A Biller, L Kronik, and JB Neaton, arXiv:1110.4928 (2011)]. We then study the self-trapping phenomenon via our reformulation of the Bethe-Salpeter excited-state forces approximation of Ismail-Beigi and Louie [Phys. Rev. Lett. 90, 076401 (2003)], which can describe the structural relaxation after optical excitation. Whether excitons in pentacene have charge-transfer character has been controversial in electro-absorption experiments. We use the same BSE analytic derivatives approach to calculate the changes in excitation energies due to an applied electric field to understand this experimental controversy.

Reducing cross-sectional data using a genetic algorithm method and effects on cross-section geometry and steady-flow profiles

USGS Publications Warehouse

Berenbrock, Charles E.

2015-01-01

The effects of reduced cross-sectional data points on steady-flow profiles were also determined. Thirty-five cross sections of the original steady-flow model of the Kootenai River were used. These two methods were tested for all cross sections with each cross section resolution reduced to 10, 20 and 30 data points, that is, six tests were completed for each of the thirty-five cross sections. Generally, differences from the original water-surface elevation were smaller as the number of data points in reduced cross sections increased, but this was not always the case, especially in the braided reach. Differences were smaller for reduced cross sections developed by the genetic algorithm method than the standard algorithm method.

Experiments on Antiprotons: Antiproton-Nucleon Cross Sections

DOE R&D Accomplishments Database

Chamberlain, Owen; Keller, Donald V.; Mermond, Ronald; Segre, Emilio; Steiner, Herbert M.; Ypsilantis, Tom

1957-07-22

In this paper experiments are reported on annihilation and scattering of antiprotons in H{sub 2}O , D{sub 2}O, and O{sub 2}. From the data measured it is possible to obtain an antiproton-proton and an antiproton-deuteron cross section at 457 Mev (lab). Further analysis gives the p-p and p-n cross sections as 104 mb for the p-p reaction cross section and 113 mb for the p-n reaction cross section. The respective annihilation cross sections are 89 and 74 mb. The Glauber correction necessary in order to pass from the p-d to the p-n cross section by subtraction of the p-p cross section is unfortunately large and somewhat uncertain. The data are compared with the p-p and p-n cross sections and with other results on p-p collisions.

Log-gamma directed polymer with fixed endpoints via the replica Bethe Ansatz

NASA Astrophysics Data System (ADS)

Thiery, Thimothée; Le Doussal, Pierre

2014-10-01

We study the model of a discrete directed polymer (DP) on a square lattice with homogeneous inverse gamma distribution of site random Boltzmann weights, introduced by Seppalainen (2012 Ann. Probab. 40 19-73). The integer moments of the partition sum, \\overline{Z^n} , are studied using a transfer matrix formulation, which appears as a generalization of the Lieb-Liniger quantum mechanics of bosons to discrete time and space. In the present case of the inverse gamma distribution the model is integrable in terms of a coordinate Bethe Ansatz, as discovered by Brunet. Using the Brunet-Bethe eigenstates we obtain an exact expression for the integer moments of \\overline{Z^n} for polymers of arbitrary lengths and fixed endpoint positions. Although these moments do not exist for all integer n, we are nevertheless able to construct a generating function which reproduces all existing integer moments and which takes the form of a Fredholm determinant (FD). This suggests an analytic continuation via a Mellin-Barnes transform and we thereby propose a FD ansatz representation for the probability distribution function (PDF) of Z and its Laplace transform. In the limit of a very long DP, this ansatz yields that the distribution of the free energy converges to the Gaussian unitary ensemble (GUE) Tracy-Widom distribution up to a non-trivial average and variance that we calculate. Our asymptotic predictions coincide with a result by Borodin et al (2013 Commun. Math. Phys. 324 215-32) based on a formula obtained by Corwin et al (2011 arXiv:1110.3489) using the geometric Robinson-Schensted-Knuth (gRSK) correspondence. In addition we obtain the dependence on the endpoint position and the exact elastic coefficient at a large time. We argue the equivalence between our formula and that of Borodin et al. As we will discuss, this provides a connection between quantum integrability and tropical combinatorics.

Study of BenW (n = 1-12) clusters: An electron collision perspective

NASA Astrophysics Data System (ADS)

Modak, Paresh; Kaur, Jaspreet; Antony, Bobby

2017-08-01

This article explores electron scattering cross sections by Beryllium-Tungsten clusters (BenW). Beryllium and tungsten are important elements for plasma facing wall components, especially for the deuterium/tritium phase of ITER and in the recently installed JET. The present study focuses on different electron impact interactions in terms of elastic cross section (Qel), inelastic cross section (Qinel), ionization cross section (Qion), and momentum transfer cross section (Qmtcs) for the first twelve clusters belonging to the BenW family. It also predicts the evolution of the cross section with the size of the cluster. These cross sections are used as an input to model processes in plasma. The ionization cross section presented here is compared with the available reported data. This is the first comprehensive report on cross section data for all the above-mentioned scattering channels, to the best of our knowledge. Such broad analysis of cross section data gives vital insight into the study of local chemistry of electron interactions with BenW (n = 1-12) clusters in plasma.

Averaging cross section data so we can fit it

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

Brown, D.

2014-10-23

The 56Fe cross section we are interested in have a lot of fluctuations. We would like to fit the average of the cross section with cross sections calculated within EMPIRE. EMPIRE is a Hauser-Feshbach theory based nuclear reaction code, requires cross sections to be smoothed using a Lorentzian profile. The plan is to fit EMPIRE to these cross sections in the fast region (say above 500 keV).

New cross sections for H on H2 collisional transitions

NASA Astrophysics Data System (ADS)

Zou, Qianxia

2011-12-01

The cross section for H on H2 collisions is important for astrophysics as well as our understanding of the simple chemical systems. This is the simplest atom-molecule cross section. With a new H3 potential surface by Mielke et al., we have modified the ABC code by Skouteris, Castillo and Manolopoulos to calculate new cross sections. These cross sections are compared to previous cross section calculations.

A computer program for analyzing channel geometry

USGS Publications Warehouse

Regan, R.S.; Schaffranek, R.W.

1985-01-01

The Channel Geometry Analysis Program (CGAP) provides the capability to process, analyze, and format cross-sectional data for input to flow/transport simulation models or other computational programs. CGAP allows for a variety of cross-sectional data input formats through use of variable format specification. The program accepts data from various computer media and provides for modification of machine-stored parameter values. CGAP has been devised to provide a rapid and efficient means of computing and analyzing the physical properties of an open-channel reach defined by a sequence of cross sections. CGAP 's 16 options provide a wide range of methods by which to analyze and depict a channel reach and its individual cross-sectional properties. The primary function of the program is to compute the area, width, wetted perimeter, and hydraulic radius of cross sections at successive increments of water surface elevation (stage) from data that consist of coordinate pairs of cross-channel distances and land surface or channel bottom elevations. Longitudinal rates-of-change of cross-sectional properties are also computed, as are the mean properties of a channel reach. Output products include tabular lists of cross-sectional area, channel width, wetted perimeter, hydraulic radius, average depth, and cross-sectional symmetry computed as functions of stage; plots of cross sections; plots of cross-sectional area and (or) channel width as functions of stage; tabular lists of cross-sectional area and channel width computed as functions of stage for subdivisions of a cross section; plots of cross sections in isometric projection; and plots of cross-sectional area at a fixed stage as a function of longitudinal distance along an open-channel reach. A Command Procedure Language program and Job Control Language procedure exist to facilitate program execution on the U.S. Geological Survey Prime and Amdahl computer systems respectively. (Lantz-PTT)

What is a global manager?

PubMed

Bartlett, C A; Ghoshal, S

1992-01-01

To compete around the world, a company needs three strategic capabilities: global-scale efficiency, local responsiveness, and the ability to leverage learning worldwide. No single "global" manager can build these capabilities. Rather, groups of specialized managers must integrate assets, resources, and people in diverse operating units. Such managers are made, not born. And how to make them is--and must be--the foremost question for corporate managers. Drawing on their research with leading transnational corporations, Christopher Bartlett and Sumantra Ghoshal identify three types of global managers. They also illustrate the responsibilities each position involves through a close look at the careers of successful executives: Leif Johansson of Electrolux, Howard Gottlieb of NEC, and Wahib Zaki of Procter & Gamble. The first type is the global business or product-division manager who must build worldwide efficiency and competitiveness. These managers recognize cross-border opportunities and risks as well as link activities and capabilities around the world. The second is the country manager whose unit is the building block for worldwide operations. These managers are responsible for understanding and interpreting local markets, building local resources and capabilities, and contributing to--and participating in--the development of global strategy. Finally, there are worldwide functional specialists--the managers whose potential is least appreciated in many traditional multinational companies. To transfer expertise from one unit to another and leverage learning, these managers must scan the company for good ideas and best practice, cross-pollinate among units, and champion innovations with worldwide applications.

Multistrand superconductor cable

DOEpatents

Borden, A.R.

1984-03-08

Improved multistrand Rutherford-type superconductor cable is produced by using strands which are preformed, prior to being wound into the cable, so that each strand has a variable cross section, with successive portions having a substantially round cross section, a transitional oval cross section, a rectangular cross section, a transitional oval cross section, a round cross section and so forth, in repetitive cycles along the length of the strand. The cable is wound and flattened so that the portions of rectangular cross section extend across the two flat sides of the cable at the strand angle. The portions of round cross section are bent at the edges of the flattened cable, so as to extend between the two flat sides. The rectangular portions of the strands slide easil

Ion dipole capture cross sections at low ion and rotational energies - Comparison of integrated capture cross sections with reaction cross sections for NH3 and H2O parent-ion collisions.

NASA Technical Reports Server (NTRS)

Dugan, J. V., Jr.; Canright, R. B., Jr.

1972-01-01

The numerical capture cross section is calculated from the capture ratio, defined as the fraction of trajectories reaching a prescribed minimum separation of 3 A. The calculated capture cross sections for a rotational temperature of 77 K suggest large reaction cross sections in 80 K experiments for the large dipole-moment target, methyl cyanide.

Characterization of Suspended Sediment Plumes Resulting from Barge Decanting in San Francisco Bay

DTIC Science & Technology

2015-06-01

was Chief, CEERD-EEW; Mark Farr was Chief, CEERD-EE; Dr. Jack Davis was the Deputy Director of ERDC-EL; and Dr. Beth Fleming was the Director of ERDC...Methodologies Oakland Harbor A description of the decanting methodology to be used at Oakland was described by the Manson Dredging Company. During

Enhancing Cost Realism through Risk-Driven Contracting: Designing Incentive Fees Based on Probabilistic Cost Estimates

DTIC Science & Technology

2012-04-01

Comparison of Management Practices in the Army, Navy, and Air Force 142Defense ARJ, April 2012, Vol. 19 No. 2 : 133–160 It appears the pendulum may be...the cost risk for requiring greater innovation. However, this natural flattening trend also leads to a potential drawback of the risk-driven

Old Glory and the Jolly Roger: The Cultural Constraints and Strategic Imperatives of Modern Piracy

DTIC Science & Technology

2009-06-01

41. Watkins , Eric. "Pirates Seize Another Tanker Off Yemen." Oil and Gas Journal (9 January 2009), http://www.ogj.com/display_article/352052/7...Piracy in the Graeco-Roman World. Cambridge: Cambridge University Press, 2002. Dobbins, James, Seth G. Jones, Keith Crane, and Beth Cole DeGrasse. The

On the Relativistic Separable Functions for the Breakup Reactions

NASA Astrophysics Data System (ADS)

Bondarenko, Serge G.; Burov, Valery V.; Rogochaya, Elena P.

2018-02-01

In the paper the so-called modified Yamaguchi function for the Bethe-Salpeter equation with a separable kernel is discussed. The type of the functions is defined by the analytic stucture of the hadron current with breakup - the reactions with interacting nucleon-nucleon pair in the final state (electro-, photo-, and nucleon-disintegration of the deuteron).

Extraction of hadron interactions above inelastic threshold in lattice QCD.

PubMed

Aoki, Sinya; Ishii, Noriyoshi; Doi, Takumi; Hatsuda, Tetsuo; Ikeda, Yoichi; Inoue, Takashi; Murano, Keiko; Nemura, Hidekatsu; Sasaki, Kenji

2011-01-01

We propose a new method to extract hadron interactions above inelastic threshold from the Nambu-Bethe-Salpeter amplitude in lattice QCD. We consider the scattering such as A + B → C + D, where A, B, C, D are names of different 1-particle states. An extension to cases where particle productions occur during scatterings is also discussed.

A Novel Experiment to Investigate the Attenuation of Alpha Particles in Air

ERIC Educational Resources Information Center

Andrews, D. G. H.

2008-01-01

A simple student experiment investigating dependence on air pressure of the attenuation of alpha particles in air is described. An equation giving the pressure needed to absorb all alpha particles of a given energy is derived from the Bethe-Bloch formula. Results are presented for the attenuation of alpha particles from americium 241 and radium…

Contemporary continuum QCD approaches to excited hadrons

NASA Astrophysics Data System (ADS)

El-Bennich, Bruno; Rojas, Eduardo

2016-03-01

Amongst the bound states produced by the strong interaction, radially excited meson and nucleon states offer an important phenomenological window into the long-range behavior of the coupling constant in Quantum Chromodynamics. We here report on some technical details related to the computation of the bound state's eigenvalue spectrum in the framework of Bethe-Salpeter and Faddeev equations.

CWC Industry Outreach III: - CWC Ratification, Implementation, Compliance and Verification (CWC Video). Volume 1. Main Report.

DTIC Science & Technology

1995-08-03

asked whether the scheduled chemicals will be assigned individual ECCNs . They were interested in whether the normal trade license applications will be...the Australia Group? B-14 AC93MC1002 Has an effort been made or is one planned to coordinate the.trade requirements on these chemicals with the ECCNs

The DMON2: A Commercially Available Broadband Acoustic Monitoring Instrument

DTIC Science & Technology

2014-09-30

Assignment of Export Control Classification Number ( ECCN ) of 6A991 by the Department of Commerce for the DMON2 (July 30, 2014), allowing the DMON2 to be...The ECCN 6A991 classification requires that an external pressure transducer be mounted in the head so that the hydrophone output can be disabled

Teaching Primary & Secondary Sources: An Earthshaking Collaboration

ERIC Educational Resources Information Center

Gustafson, Chris

2006-01-01

Does history have to be boring and dry? Not if a person takes the familiar and adds an earthshaking twist! To begin the collaborative process, work with a willing teacher. This article talks about a teaching collaboration between the author as a library media specialist and Beth who was interested in literature circle titles for her 6th grade…

Human Resource Accounting: Operationalization and Effects of Human Resource Replacement Cost System in Naval Operations.

DTIC Science & Technology

1985-12-20

example whether or not to allow inter-regional * differences in compensation because of factors such as S competition in regional labor markets , can be...the position in * Oquestion? 5. An example of how one person plotted this percentage of time is given below: - - - - If I [-T S6. Please plot the nline

Sex- and age-related differences in mid-thigh composition and muscle quality determined by computed tomography in middle-aged and elderly Japanese.

PubMed

Kasai, Takehiro; Ishiguro, Naoki; Matsui, Yasumoto; Harada, Atsushi; Takemura, Marie; Yuki, Atsumu; Kato, Yuki; Otsuka, Rei; Ando, Fujiko; Shimokata, Hiroshi

2015-06-01

Sex- and age-related differences in mid-thigh composition and muscle quality remain unclear. The present study aimed to clarify these differences using computed tomography in middle-aged and elderly Japanese. A total of 2310 participants (age 40-89 years), who were randomly selected from the local residents, underwent computed tomography examination of the right mid-thigh. Thigh circumference and cross-sectional areas of the thigh, muscle, quadriceps, non-quadriceps, fat, and bone were measured. Knee extension strength and muscle quality index (knee extension strength/quadriceps cross-sectional area) were also assessed. Sex- and age-related differences in these indices were analyzed. The thigh cross-sectional area in men and women decreased by 0.6% and 0.5%/year, respectively, because of a decrease in muscle cross-sectional area (men 75.2%, women 40.6%), fat cross-sectional area (men 24.4%, women 59.6%) and bone cross-sectional area (men 0.5%, women -0.2%). Muscle cross-sectional area in men and women decreased by 0.6% and 0.4%/year, respectively, because of a decrease in quadriceps cross-sectional area (men 65.6%, women 81.6%) and non-quadriceps cross-sectional area (men 34.4%, women 18.4%). Muscle quality in men and women decreased by 0.4% and 0.3%/year, respectively. Thigh cross-sectional area decreased with age mainly because of a decrease in muscle cross-sectional area in men and fat cross-sectional area in women. The rate of decrease in muscle cross-sectional area was 1.5-fold higher in men than in women. Muscle cross-sectional area decreased with age mainly because of a decrease in quadriceps cross-sectional area, especially in women. Decrease in muscle quality with age was similar in both sexes. © 2014 Japan Geriatrics Society.

Total cross sections for positrons scattered elastically from helium based on new measurements of total ionization cross sections

NASA Technical Reports Server (NTRS)

Diana, L. M.; Chaplin, R. L.; Brooks, D. L.; Adams, J. T.; Reyna, L. K.

1990-01-01

An improved technique is presented for employing the 2.3m spectrometer to measure total ionization cross sections, Q sub ion, for positrons incident on He. The new ionization cross section agree with the values reported earlier. Estimates are also presented of total elastic scattering cross section, Q sub el, obtained by subtracting from total scattering cross sections, Q sub tot, reported in the literature, the Q sub ion and Q sub Ps (total positronium formation cross sections) and total excitation cross sections, Q sub ex, published by another researcher. The Q sub ion and Q sub el measured with the 3m high resolution time-of-flight spectrometer for 54.9eV positrons are in accord with the results from the 2.3m spectrometer. The ionization cross sections are in fair agreement with theory tending for the most part to be higher, especially at 76.3 and 88.5eV. The elastic cross section agree quite well with theory to the vicinity of 50eV, but at 60eV and above the experimental elastic cross sections climb to and remain at about 0.30 pi a sub o sq while the theoretical values steadily decrease.

Nano-fabricated plasmonic optical transformer

DOEpatents

Choo, Hyuck; Cabrini, Stefano; Schuck, P. James; Liang, Xiaogan; Yablonovitch, Eli

2015-06-09

The present invention provides a plasmonic optical transformer to produce a highly focuses optical beam spot, where the transformer includes a first metal layer, a dielectric layer formed on the first metal layer, and a second metal layer formed on the dielectric layer, where the first metal layer, the dielectric layer, and the second layer are patterned to a shape including a first section having a first cross section, a second section following the first section having a cross-section tapering from the first section to a smaller cross-section, and a third section following the second section having a cross-section matching the tapered smaller cross-section of the second section.

Geologic cross section C-C' through the Appalachian basin from Erie County, north-central Ohio, to the Valley and Ridge province, Bedford County, south-central Pennsylvania

USGS Publications Warehouse

Ryder, Robert T.; Trippi, Michael H.; Swezey, Christopher S.; Crangle, Robert D.; Hope, Rebecca S.; Rowan, Elisabeth L.; Lentz, Erika E.

2012-01-01

Geologic cross section C-C' is the third in a series of cross sections constructed by the U.S. Geological Survey (USGS) to document and improve understanding of the geologic framework and petroleum systems of the Appalachian basin. Cross section C-C' provides a regional view of the structural and stratigraphic framework of the Appalachian basin from north-central Ohio to the Valley and Ridge province in south-central Pennsylvania, a distance of approximately 260 miles (mi). This cross section is a companion to cross sections E-E' and D-D' that are located about 50 to 125 mi and 25 to 50 mi, respectively, to the southwest. Cross section C-C' contains much information that is useful for evaluating energy resources in the Appalachian basin. Although specific petroleum systems are not identified on the cross section, many of their key elements (such as source rocks, reservoir rocks, seals, and traps) can be inferred from lithologic units, unconformities, and geologic structures shown on the cross section. Other aspects of petroleum systems (such as the timing of petroleum generation and preferred migration pathways) may be evaluated by burial history, thermal history, and fluid flow models based on what is shown on the cross section. Cross section C-C' also provides a general framework (stratigraphic units and general rock types) for the coal-bearing section, although the cross section lacks the detail to illustrate key elements of coal systems (such as paleoclimate, coal quality, and coal rank). In addition, cross section C-C' may be used as a reconnaissance tool to identify plausible geologic structures and strata for the subsurface storage of liquid waste or for the sequestration of carbon dioxide.

Multistrand superconductor cable

DOEpatents

Borden, Albert R.

1985-01-01

Improved multistrand Rutherford-type superconductor cable is produced by using strands which are preformed, prior to being wound into the cable, so that each strand has a variable cross section, with successive portions having a substantially round cross section, a transitional oval cross section, a rectangular cross section, a transitional oval cross section, a round cross section and so forth, in repetitive cycles along the length of the strand. The cable is wound and flattened so that the portions of rectangular cross section extend across the two flat sides of the cable at the strand angle. The portions of round cross section are bent at the edges of the flattened cable, so as to extend between the two flat sides. The rectangular portions of the strands slide easily over one another, so as to facilitate flexing and bending of the cable, while also minimizing the possibility of causing damage to the strands by such flexing or bending. Moreover, the improved cable substantially maintains its compactness and cross-sectional shape when the cable is flexed or bent.

AMPX: a modular code system for generating coupled multigroup neutron-gamma libraries from ENDF/B

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

Greene, N.M.; Lucius, J.L.; Petrie, L.M.

1976-03-01

AMPX is a modular system for producing coupled multigroup neutron-gamma cross section sets. Basic neutron and gamma cross-section data for AMPX are obtained from ENDF/B libraries. Most commonly used operations required to generate and collapse multigroup cross-section sets are provided in the system. AMPX is flexibly dimensioned; neutron group structures, and gamma group structures, and expansion orders to represent anisotropic processes are all arbitrary and limited only by available computer core and budget. The basic processes provided will (1) generate multigroup neutron cross sections; (2) generate multigroup gamma cross sections; (3) generate gamma yields for gamma-producing neutron interactions; (4) combinemore » neutron cross sections, gamma cross sections, and gamma yields into final ''coupled sets''; (5) perform one-dimensional discrete ordinates transport or diffusion theory calculations for neutrons and gammas and, on option, collapse the cross sections to a broad-group structure, using the one-dimensional results as weighting functions; (6) plot cross sections, on option, to facilitate the ''evaluation'' of a particular multigroup set of data; (7) update and maintain multigroup cross section libraries in such a manner as to make it not only easy to combine new data with previously processed data but also to do it in a single pass on the computer; and (8) output multigroup cross sections in convenient formats for other codes. (auth)« less

Trunk Muscle Size and Composition Assessment in Older Adults with Chronic Low Back Pain: An Intra-Examiner and Inter-Examiner Reliability Study.

PubMed

Sions, Jaclyn Megan; Smith, Andrew Craig; Hicks, Gregory Evan; Elliott, James Matthew

2016-08-01

To evaluate intra- and inter-examiner reliability for the assessment of relative cross-sectional area, muscle-to-fat infiltration indices, and relative muscle cross-sectional area, i.e., total cross-sectional area minus intramuscular fat, from T1-weighted magnetic resonance images obtained in older adults with chronic low back pain. Reliability study. n = 13 (69.3 ± 8.2 years old) After lumbar magnetic resonance imaging, two examiners produced relative cross-sectional area measurements of multifidi, erector spinae, psoas, and quadratus lumborum by tracing regions of interest just inside fascial borders. Pixel-intensity summaries were used to determine muscle-to-fat infiltration indices; relative muscle cross-sectional area was calculated. Intraclass correlation coefficients were used to estimate intra- and inter-examiner reliability; standard error of measurement was calculated. Intra-examiner intraclass correlation coefficient point estimates for relative cross-sectional area, muscle-to-fat infiltration indices, and relative muscle cross-sectional area were excellent for multifidi and erector spinae across levels L2-L5 (ICC = 0.77-0.99). At L3, intra-examiner reliability was excellent for relative cross-sectional area, muscle-to-fat infiltration indices, and relative muscle cross-sectional area for both psoas and quadratus lumborum (ICC = 0.81-0.99). Inter-examiner intraclass correlation coefficients ranged from poor to excellent for relative cross-sectional area, muscle-to-fat infiltration indices, and relative muscle cross-sectional area. Assessment of relative cross-sectional area, muscle-to-fat infiltration indices, and relative muscle cross-sectional area in older adults with chronic low back pain can be reliably determined by one examiner from T1-weighted images. Such assessments provide valuable information, as muscle-to-fat infiltration indices and relative muscle cross-sectional area indicate that a substantial amount of relative cross-sectional area may be magnetic resonance-visible intramuscular fat in older adults with chronic low back pain. © 2015 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Calculation of total and ionization cross sections for electron scattering by primary benzene compounds

NASA Astrophysics Data System (ADS)

Singh, Suvam; Naghma, Rahla; Kaur, Jaspreet; Antony, Bobby

2016-07-01

The total and ionization cross sections for electron scattering by benzene, halobenzenes, toluene, aniline, and phenol are reported over a wide energy domain. The multi-scattering centre spherical complex optical potential method has been employed to find the total elastic and inelastic cross sections. The total ionization cross section is estimated from total inelastic cross section using the complex scattering potential-ionization contribution method. In the present article, the first theoretical calculations for electron impact total and ionization cross section have been performed for most of the targets having numerous practical applications. A reasonable agreement is obtained compared to existing experimental observations for all the targets reported here, especially for the total cross section.

Parameterized Cross Sections for Pion Production in Proton-Proton Collisions

NASA Technical Reports Server (NTRS)

Blattnig, Steve R.; Swaminathan, Sudha R.; Kruger, Adam T.; Ngom, Moussa; Norbury, John W.; Tripathi, R. K.

2000-01-01

An accurate knowledge of cross sections for pion production in proton-proton collisions finds wide application in particle physics, astrophysics, cosmic ray physics, and space radiation problems, especially in situations where an incident proton is transported through some medium and knowledge of the output particle spectrum is required when given the input spectrum. In these cases, accurate parameterizations of the cross sections are desired. In this paper much of the experimental data are reviewed and compared with a wide variety of different cross section parameterizations. Therefore, parameterizations of neutral and charged pion cross sections are provided that give a very accurate description of the experimental data. Lorentz invariant differential cross sections, spectral distributions, and total cross section parameterizations are presented.

A Salzburg Global Seminar: "Optimizing Talent: Closing Education and Social Mobility Gaps Worldwide." Policy Notes. Volume 20, Number 3, Fall 2012

ERIC Educational Resources Information Center

Schwartz, Robert

2012-01-01

This issue of ETS Policy Notes (Vol. 20, No. 3) provides highlights from the Salzburg Global Seminar in December 2011. The seminar focused on bettering the educational and life prospects of students up to age 18 worldwide. [This article was written with the assistance of Beth Brody.

Communication in Civil-Military Cooperation

DTIC Science & Technology

2007-03-01

8 sides have different roles, different aims, different motives and, what we have to remember, different philosophies, and these need to be...the purpose of intelligence production cannot always be shared with civilian organizations and authorities,”35 because the fragile trust can easily be...drastically restrain the actions of those with anti-peace motivations . Appropriately culturally sensitive peacekeepers can become caring “neighbors

The Role of the State Educational Agency in the Development of Innovative Programs in Student Teaching.

ERIC Educational Resources Information Center

Edelfelt, Roy A., Ed.

In the introduction to this collection of papers, William Drummond summarizes the national conference proceedings and personal reactions to them. Chapter 1, "The Revolution Explosion," is a talk by Frankie Beth Nelson about the way an anthropologist looks at the school and its purposes. Chapter 2 (SP 002 631), "Student Teaching: The State of the…

The Impossibilities of Neutrality: Other Geopolitical Metaphors for Academic Development Units

ERIC Educational Resources Information Center

Holmes, Trevor; Manathunga, Catherine; Potter, Michael K.; Wuetherick, Brad

2012-01-01

This paper responds to the occasionally stated imperative in some contexts to be neutral as part of being an academic development unit (ADU). For over a decade at separate professional meetings of developers, two of the authors have heard the refrain that they need to be--or at least be perceived to be--"the Switzerland" of their…

Understanding Girls' Circle as an Intervention on Perceived Social Support, Body Image, Self-Efficacy, Locus of Control, and Self-Esteem

ERIC Educational Resources Information Center

Steese, Stephanie; Dollette, Maya; Phillips, William; Hossfeld, Elizabeth; Matthews, Gail; Taormina, Giovanna

2006-01-01

The Girls' Circle is a support group for adolescent girls developed by Beth Hossfeld and Giovanna Taormina as a unique program that addresses the needs of girls by focusing on increasing connections, building empathic skills, and developing resiliency. The present study evaluates the effectiveness of the Girls' Circle intervention on improving…

Alpher, Ralph Asher (1921-)

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

Physicist, born in Washington, DC. With HANS BETHE and GEORGE GAMOW, he proposed in 1948 the `alpha-beta-gamma' theory of the creation of the elements by successive addition of nucleons to hydrogen to build up the periodic table (the alpha part of the name of the theory referred to Alpher). This idea, subsequently shown by MARGARET BURBIDGE, Geoffery Burbidge, WILLIAM FOWLER and FRED HOYLE to be...

Senate Rostrum: Academic Senate for California Community Colleges Newsletter

ERIC Educational Resources Information Center

Academic Senate for California Community Colleges, 2010

2010-01-01

The Rostrum is a quarterly publication of the Academic Senate for California Community Colleges. The following articles are included in this issue: (1) The Need for full Time faculty (again) by Jane Patton; (2) Reading May Be the Key to Unlocking Basic Skills Success by Janet Fulks; (3) Diversity Institute on the Right Track by Beth Smith; (4)…

Library Orientation Transformation: From Paper Map to Augmented Reality

ERIC Educational Resources Information Center

Mulch, Beth Ebenstein

2014-01-01

In this article, high school librarian Beth Ebenstein Mulch describes how she used iPads to introduce students at T. C. Williams High School (Alexandria, Virginia) to the school library. Her goal was for the library to come to life in front of new students and for them to learn from peers about all the great resources and services their library…

An energy-dependent electron backscattering coefficient

NASA Astrophysics Data System (ADS)

Williamson, W., Jr.; Antolak, A. J.; Meredith, R. J.

1987-05-01

An energy-dependent electron backscattering coefficient is derived based on the continuous slowing down approximation and the Bethe stopping power. Backscattering coefficients are given for 10-50-keV electrons incident on bulk and thin-film aluminum, silver, and gold targets. The results are compared with the Everhart theory and empirical fits to experimental data. The energy-dependent theory agrees better with experimental work.

Forging Ahead! Teachers Reflect on the Early Adopter Program to Implement the Common Core State Standards

ERIC Educational Resources Information Center

Koning, Erin; Houghtby, Beth; Izard, Patrice; Schuler, Jennifer

2014-01-01

This "water cooler" column features e-mail conversations between Erin Koning and three teachers--Beth, Jenna, and Patrice--and is a reflection of their participation in a Chicago Public School (CPS), professional development series designed to support the implementation of the Common Core State Standards (CCSS) in grades K-12. At the…

Bethe, Hans Albrecht (1906-)

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

Physicist, born in Strasburg, Germany (present-day France), Nobel prizewinner (1967). As professor of physics at Cornell University he worked out the nuclear reactions occurring in the Sun. He worked on the development of the atomic bomb in the Manhatten project, and, after the second World War, pursued again research on stellar nuclear energy sources and the origin of the chemical elements in th...

Benchmark of Ab Initio Bethe-Salpeter Equation Approach with Numeric Atom-Centered Orbitals

NASA Astrophysics Data System (ADS)

Liu, Chi; Kloppenburg, Jan; Kanai, Yosuke; Blum, Volker

The Bethe-Salpeter equation (BSE) approach based on the GW approximation has been shown to be successful for optical spectra prediction of solids and recently also for small molecules. We here present an all-electron implementation of the BSE using numeric atom-centered orbital (NAO) basis sets. In this work, we present benchmark of BSE implemented in FHI-aims for low-lying excitation energies for a set of small organic molecules, the well-known Thiel's set. The difference between our implementation (using an analytic continuation of the GW self-energy on the real axis) and the results generated by a fully frequency dependent GW treatment on the real axis is on the order of 0.07 eV for the benchmark molecular set. We study the convergence behavior to the complete basis set limit for excitation spectra, using a group of valence correlation consistent NAO basis sets (NAO-VCC-nZ), as well as for standard NAO basis sets for ground state DFT with extended augmentation functions (NAO+aug). The BSE results and convergence behavior are compared to linear-response time-dependent DFT, where excellent numerical convergence is shown for NAO+aug basis sets.

Macroscopic and microscopic components of exchange-correlation interactions

NASA Astrophysics Data System (ADS)

Sottile, F.; Karlsson, K.; Reining, L.; Aryasetiawan, F.

2003-11-01

We consider two commonly used approaches for the ab initio calculation of optical-absorption spectra, namely, many-body perturbation theory based on Green’s functions and time-dependent density-functional theory (TDDFT). The former leads to the two-particle Bethe-Salpeter equation that contains a screened electron-hole interaction. We approximate this interaction in various ways, and discuss in particular the results obtained for a local contact potential. This, in fact, allows us to straightforwardly make the link to the TDDFT approach, and to discuss the exchange-correlation kernel fxc that corresponds to the contact exciton. Our main results, illustrated in the examples of bulk silicon, GaAs, argon, and LiF, are the following. (i) The simple contact exciton model, used on top of an ab initio calculated band structure, yields reasonable absorption spectra. (ii) Qualitatively extremely different fxc can be derived approximatively from the same Bethe-Salpeter equation. These kernels can however yield very similar spectra. (iii) A static fxc, both with or without a long-range component, can create transitions in the quasiparticle gap. To the best of our knowledge, this is the first time that TDDFT has been shown to be able to reproduce bound excitons.

A systematic approach to sketch Bethe-Salpeter equation

NASA Astrophysics Data System (ADS)

Qin, Si-xue

2016-03-01

To study meson properties, one needs to solve the gap equation for the quark propagator and the Bethe-Salpeter (BS) equation for the meson wavefunction, self-consistently. The gluon propagator, the quark-gluon vertex, and the quark-anti-quark scattering kernel are key pieces to solve those equations. Predicted by lattice-QCD and Dyson-Schwinger analyses of QCD's gauge sector, gluons are non-perturbatively massive. In the matter sector, the modeled gluon propagator which can produce a veracious description of meson properties needs to possess a mass scale, accordingly. Solving the well-known longitudinal Ward-Green-Takahashi identities (WGTIs) and the less-known transverse counterparts together, one obtains a nontrivial solution which can shed light on the structure of the quark-gluon vertex. It is highlighted that the phenomenologically proposed anomalous chromomagnetic moment (ACM) vertex originates from the QCD Lagrangian symmetries and its strength is proportional to the magnitude of dynamical chiral symmetry breaking (DCSB). The color-singlet vector and axial-vector WGTIs can relate the BS kernel and the dressed quark-gluon vertex to each other. Using the relation, one can truncate the gap equation and the BS equation, systematically, without violating crucial symmetries, e.g., gauge symmetry and chiral symmetry.

On the worldsheet theory of the type IIA {text{Ad}}{{text{S}}_4} × mathbb{C}{mathbb{P}_3} superstring

NASA Astrophysics Data System (ADS)

Sundin, Per

2010-04-01

We perform a detailed study of the type IIA superstring in {text{Ad}}{{text{S}}_4} × mathbb{C}{mathbb{P}_3} . After introducing suitable bosonic light-cone and fermionic kappa worldsheet gauges we derive the pure boson and fermion SU(2|2)×U(1) covariant light-cone Hamiltonian up to quartic order in fields. As a first application of our derivation we calculate energy shifts for string configurations in a closed fermionic subsector and successfully match these with a set of light-cone Bethe equations. We then turn to investigate the mismatch between the degrees of freedom of scattering states and oscillatory string modes. Since only light string modes appear as fundamental Bethe roots in the scattering theory, the physical role of the remaining 4 F + 4 B massive oscillators is rather unclear. By continuing a line of research initiated by Zarembo, we shed light on this question by calculating quantum corrections for the propagators of the bosonic massive fields. We show that, once loop corrections are incorporated, the massive coordinates dissolve in a continuum state of two light particles.

Effects of Composite Pions on the Chiral Condensate within the PNJL Model at Finite Temperature

NASA Astrophysics Data System (ADS)

Blaschke, D.; Dubinin, A.; Ebert, D.; Friesen, A. V.

2018-05-01

We investigate the effect of composite pions on the behaviour of the chiral condensate at finite temperature within the Polyakov-loop improved NJL model. To this end we treat quark-antiquark correlations in the pion channel (bound states and scattering continuum) within a Beth-Uhlenbeck approach that uses medium-dependent phase shifts. A striking medium effect is the Mott transition which occurs when the binding energy vanishes and the discrete pion bound state merges the continuum. This transition is triggered by the lowering of the continuum edge due to the chiral restoration transition. This in turn also entails a modification of the Polyakov-loop so that the SU(3) center symmetry gets broken at finite temperature and dynamical quarks (and gluons) appear in the system, taking over the role of the dominant degrees of freedom from the pions. At low temperatures our model reproduces the chiral perturbation theory result for the chiral condensate while at high temperatures the PNJL model result is recovered. The new aspect of the current work is a consistent treatment of the chiral restoration transition region within the Beth-Uhlenbeck approach on the basis of mesonic phase shifts for the treatment of the correlations.

Bethe-Salpeter wave functions of ηc(1S, 2S) and ψ(1S, 2S) states: local-potential description of the charmonium system revisited

NASA Astrophysics Data System (ADS)

Nochi, Kazuki; Kawanai, Taichi; Sasaki, Shoichi

2018-03-01

The quark potential models with an energy-independent central potential have been successful for understanding the conventional charmonium states especially below the open charm threshold. As one might consider, however, the interquark potential is in general energy-dependent, and its tendency gets stronger in higher lying states. Confirmation of whether the interquark potential is energy-independent is also important to verify the validity of the quark potential models. In this talk, we examine the energy dependence of the charmonium potential, which can be determined from the Bethe-Salpeter (BS) amplitudes of cc̅ mesons in lattice QCD.We first calculate the BS amplitudes of radially excited charmonium states, the ηc(2S) and ψ(2S) states, using the variational method and then determine both the quark kinetic mass and the charmonium potential within the HAL QCD method. Through a direct comparison of charmonium potentials determined from both the 1S and 2S states, we confirm that neither the central nor spin-spin potential shows visible energy dependence at least up to 2S state.

Symmetric and anti-symmetric LS hyperon potentials from lattice QCD

NASA Astrophysics Data System (ADS)

Ishii, Noriyoshi; Murano, Keiko; Nemura, Hidekatsu; Sasaki, Kenji; Inoue, Takashi; HAL QCD Collaboration

2014-09-01

We present recent results of odd-parity hyperon-hyperon potentials from lattice QCD. By using HAL QCD method, we generate hyperon-hyperon potentials from Nambu-Bethe-Salpeter (NBS) wave functions generated by lattice QCD simulation in the flavor SU(3) limit. Potentials in the irreducible flavor SU(3) representations are combined to make a Lambda-N potential which has a strong symmetric LS potential and a weak anti-symmetric LS potential. We discuss a possible cancellation between symmetric and anti-symmetric LS (Lambda-N) potentials after the coupled Sigma-N sector is integrated out. We present recent results of odd-parity hyperon-hyperon potentials from lattice QCD. By using HAL QCD method, we generate hyperon-hyperon potentials from Nambu-Bethe-Salpeter (NBS) wave functions generated by lattice QCD simulation in the flavor SU(3) limit. Potentials in the irreducible flavor SU(3) representations are combined to make a Lambda-N potential which has a strong symmetric LS potential and a weak anti-symmetric LS potential. We discuss a possible cancellation between symmetric and anti-symmetric LS (Lambda-N) potentials after the coupled Sigma-N sector is integrated out. This work is supported by JSPS KAKENHI Grant Number 25400244.

An investigation of MCNP6.1 beryllium oxide S(α, β) cross sections

DOE PAGES

Sartor, Raymond F.; Glazener, Natasha N.

2016-03-08

In MCNP6.1, materials are constructed by identifying the constituent isotopes (or elements in a few cases) individually. This list selects the corresponding microscopic cross sections calculated from the free-gas model to create the material macroscopic cross sections. Furthermore, the free-gas model and the corresponding material macroscopic cross sections assume that the interactions of atoms do not affect the nuclear cross sections.

DBCC Software as Database for Collisional Cross-Sections

NASA Astrophysics Data System (ADS)

Moroz, Daniel; Moroz, Paul

2014-10-01

Interactions of species, such as atoms, radicals, molecules, electrons, and photons, in plasmas used for materials processing could be very complex, and many of them could be described in terms of collisional cross-sections. Researchers involved in plasma simulations must select reasonable cross-sections for collisional processes for implementing them into their simulation codes to be able to correctly simulate plasmas. However, collisional cross-section data are difficult to obtain, and, for some collisional processes, the cross-sections are still not known. Data on collisional cross-sections can be obtained from numerous sources including numerical calculations, experiments, journal articles, conference proceedings, scientific reports, various universities' websites, national labs and centers specifically devoted to collecting data on cross-sections. The cross-sections data received from different sources could be partial, corresponding to limited energy ranges, or could even not be in agreement. The DBCC software package was designed to help researchers in collecting, comparing, and selecting cross-sections, some of which could be constructed from others or chosen as defaults. This is important as different researchers may place trust in different cross-sections or in different sources. We will discuss the details of DBCC and demonstrate how it works and why it is beneficial to researchers working on plasma simulations.

Geologic Cross Section E-E' through the Appalachian Basin from the Findlay Arch, Wood County, Ohio, to the Valley and Ridge Province, Pendleton County, West Virginia

USGS Publications Warehouse

Ryder, Robert T.; Swezey, Christopher S.; Crangle, Robert D.; Trippi, Michael H.

2008-01-01

Geologic cross section E-E' is the first in a series of cross sections planned by the U.S. Geological Survey (USGS) to document and improve understanding of the geologic framework and petroleum systems of the Appalachian basin. Cross section E-E' provides a regional view of the structural and stratigraphic framework of the basin from the Findlay arch in northwestern Ohio to the Valley and Ridge province in eastern West Virginia, a distance of approximately 380 miles (mi) (fig. 1, on sheet 1). Cross section E-E' updates earlier geologic cross sections through the central Appalachian basin by Renfro and Feray (1970), Bennison (1978), and Bally and Snelson (1980) and a stratigraphic cross section by Colton (1970). Although other published cross sections through parts of the basin show more structural detail (for example, Shumaker, 1985; Kulander and Dean, 1986) and stratigraphic detail (for example, Ryder, 1992; de Witt and others, 1993; Hettinger, 2001), these other cross sections are of more limited extent geographically and stratigraphically. Although specific petroleum systems in the Appalachian basin are not identified on the cross section, many of their key elements (such as source rocks, reservoir rocks, seals, and traps) can be inferred from lithologic units, unconformities, and geologic structures shown on the cross section. Other aspects of petroleum systems (such as the timing of petroleum generation and preferred migration pathways) may be evaluated by burial history, thermal history, and fluid flow models based on information shown on the cross section. Cross section E-E' lacks the detail to illustrate key elements of coal systems (such as paleoclimate, coal quality, and coal rank), but it does provide a general framework (stratigraphic units and general rock types) for the coal-bearing section. Also, cross section E-E' may be used as a reconnaissance tool to identify plausible geologic structures and strata for the subsurface storage of liquid waste (for example, Colton, 1961; Lloyd and Reid, 1990) or for the sequestration of carbon dioxide (for example, Smith and others, 2002; Lucier and others, 2006).

A comparison of total reaction cross section models used in particle and heavy ion transport codes

NASA Astrophysics Data System (ADS)

Sihver, Lembit; Lantz, M.; Takechi, M.; Kohama, A.; Ferrari, A.; Cerutti, F.; Sato, T.

To be able to calculate the nucleon-nucleus and nucleus-nucleus total reaction cross sections with precision is very important for studies of basic nuclear properties, e.g. nuclear structure. This is also of importance for particle and heavy ion transport calculations because, in all particle and heavy ion transport codes, the probability function that a projectile particle will collide within a certain distance x in the matter depends on the total reaction cross sections. Furthermore, the total reaction cross sections will also scale the calculated partial fragmentation cross sections. It is therefore crucial that accurate total reaction cross section models are used in the transport calculations. In this paper, different models for calculating nucleon-nucleus and nucleus-nucleus total reaction cross sections are compared and discussed.

Vertically stabilized elongated cross-section tokamak

DOEpatents

Sheffield, George V.

1977-01-01

This invention provides a vertically stabilized, non-circular (minor) cross-section, toroidal plasma column characterized by an external separatrix. To this end, a specific poloidal coil means is added outside a toroidal plasma column containing an endless plasma current in a tokamak to produce a rectangular cross-section plasma column along the equilibrium axis of the plasma column. By elongating the spacing between the poloidal coil means the plasma cross-section is vertically elongated, while maintaining vertical stability, efficiently to increase the poloidal flux in linear proportion to the plasma cross-section height to achieve a much greater plasma volume than could be achieved with the heretofore known round cross-section plasma columns. Also, vertical stability is enhanced over an elliptical cross-section plasma column, and poloidal magnetic divertors are achieved.

BACKSCAT Lidar Simulation Version 3.0: Technical Documentation and Users Guide

DTIC Science & Technology

1992-12-03

Raman Cross Section of Some Simple Gases, J. Opt. Soc. Am., 63:73. 20 Penny, C.M., St. Peters, R.L., and Lapp, M., (1974) Absolute Rotational Raman...of the molecule, and the remaining columns list the relative normalized cross sections for the respective excitation wavelength. The absolute Raman...cross section is obtained by simply multiplying the relative normalized cross section for a molecular species of interest by the absolute cross section

Energy and Mass-Number Dependence of Hadron-Nucleus Total Reaction Cross Sections

NASA Astrophysics Data System (ADS)

Kohama, Akihisa; Iida, Kei; Oyamatsu, Kazuhiro

2016-09-01

We thoroughly investigate how proton-nucleus total reaction cross sections depend on the target mass number A and the proton incident energy. In doing so, we systematically analyze nuclear reaction data that are sensitive to nuclear size, namely, proton-nucleus total reaction cross sections and differential elastic cross sections, using a phenomenological black-sphere approximation of nuclei that we are developing. In this framework, the radius of the black sphere is found to be a useful length scale that simultaneously accounts for the observed proton-nucleus total reaction cross section and first diffraction peak in the proton elastic differential cross section. This framework, which is shown here to be applicable to antiprotons, is expected to be applicable to any kind of projectile that is strongly attenuated in the nucleus. On the basis of a cross-section formula constructed within this framework, we find that a less familiar A1/6 dependence plays a crucial role in describing the energy dependence of proton-nucleus total reaction cross sections.

Activation cross section and isomeric cross-section ratio for the 151Eu(n,2n)150m,gEu process

NASA Astrophysics Data System (ADS)

Luo, Junhua; Li, Suyuan; Jiang, Li

2018-07-01

The cross sections of 151Eu(n,2n)150m,gEu reactions and their isomeric cross section ratios σm/σt have been measured experimentally. Cross sections are measured, relative to a reference 93Nb(n,2n)92mNb reaction cross section, by means of the activation technique at three neutron energies 13.5, 14.1, and 14.8 MeV. Monoenergetic neutron beams were formed via the 3H(d,n)4He reaction and both Eu2O3 samples and Nb monitor foils were activated together to determine the reaction cross section and the incident neutron flux. The activities induced in the reaction products were measured using high-resolution gamma ray spectroscopy. Cross sections were also evaluated theoretically using the numerical nuclear model code, TALYS-1.8 with different level density options at neutron energies varying from the reaction threshold to 20 MeV. Results are discussed and compared with the corresponding literature.

Total reaction cross sections in CEM and MCNP6 at intermediate energies

DOE PAGES

Kerby, Leslie M.; Mashnik, Stepan G.

2015-05-14

Accurate total reaction cross section models are important to achieving reliable predictions from spallation and transport codes. The latest version of the Cascade Exciton Model (CEM) as incorporated in the code CEM03.03, and the Monte Carlo N-Particle transport code (MCNP6), both developed at Los Alamos National Laboratory (LANL), each use such cross sections. Having accurate total reaction cross section models in the intermediate energy region (50 MeV to 5 GeV) is very important for different applications, including analysis of space environments, use in medical physics, and accelerator design, to name just a few. The current inverse cross sections used inmore » the preequilibrium and evaporation stages of CEM are based on the Dostrovsky et al. model, published in 1959. Better cross section models are now available. Implementing better cross section models in CEM and MCNP6 should yield improved predictions for particle spectra and total production cross sections, among other results.« less

Total reaction cross sections in CEM and MCNP6 at intermediate energies

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

Kerby, Leslie M.; Mashnik, Stepan G.

Accurate total reaction cross section models are important to achieving reliable predictions from spallation and transport codes. The latest version of the Cascade Exciton Model (CEM) as incorporated in the code CEM03.03, and the Monte Carlo N-Particle transport code (MCNP6), both developed at Los Alamos National Laboratory (LANL), each use such cross sections. Having accurate total reaction cross section models in the intermediate energy region (50 MeV to 5 GeV) is very important for different applications, including analysis of space environments, use in medical physics, and accelerator design, to name just a few. The current inverse cross sections used inmore » the preequilibrium and evaporation stages of CEM are based on the Dostrovsky et al. model, published in 1959. Better cross section models are now available. Implementing better cross section models in CEM and MCNP6 should yield improved predictions for particle spectra and total production cross sections, among other results.« less

Review and history of photon cross section calculations.

PubMed

Hubbell, J H

2006-07-07

Photon (x-ray, gamma-ray, bremsstrahlung) mass attenuation coefficients, mu/rho, are among the most widely used physical parameters employed in medical diagnostic and therapy computations, as well as in diverse applications in other fields such as nuclear power plant shielding, health physics and industrial irradiation and monitoring, and in x-ray crystallography. This review traces the evolution of this data base from its empirical beginnings totally derived from measurements beginning in 1907 by Barkla and Sadler and continuing up through the 1935 Allen compilation (published virtually unchanged in all editions up through 1971-1972 of the Chemical Rubber Handbook), to the 1949 semi-empirical compilation of Victoreen, as our theoretical understanding of the constituent Compton scattering, photoabsorption and pair production interactions of photons with atoms became more quantitative. The 1950s saw the advent of completely theoretical (guided by available measured data) systematic compilations such as in the works of Davisson and Evans, and by White-Grodstein under the direction of Fano, using mostly theory developed in the 1930s (pre-World War II) by Sauter, Bethe, Heitler and others. Post-World War II new theoretical activity, and the introduction of the electronic automatic computer, led to the more extensive and more accurate compilations in the 1960s and 1970s by Storm and Israel, and by Berger and Hubbell. Today's mu/rho compilations by Cullen et al, by Seltzer, Berger and Hubbell, and by others, collectively spanning the ten decades of photon energy from 10 eV to 100 GeV, for all elements Z= 1 to 100, draw heavily on the 1970s shell-by-shell photoabsorption computations of Scofield, the 1960s coherent and incoherent scattering computations of Cromer et al, and the 1980 computations of electron-positron pair and triplet computations of Hubbell, Gimm and Øverbø, these names being representative of the vast legions of other researchers whose work fed into these computations.

REVIEW: Review and history of photon cross section calculations

NASA Astrophysics Data System (ADS)

Hubbell, J. H.

2006-07-01

Photon (x-ray, gamma-ray, bremsstrahlung) mass attenuation coefficients, μ/ρ, are among the most widely used physical parameters employed in medical diagnostic and therapy computations, as well as in diverse applications in other fields such as nuclear power plant shielding, health physics and industrial irradiation and monitoring, and in x-ray crystallography. This review traces the evolution of this data base from its empirical beginnings totally derived from measurements beginning in 1907 by Barkla and Sadler and continuing up through the 1935 Allen compilation (published virtually unchanged in all editions up through 1971-1972 of the Chemical Rubber Handbook), to the 1949 semi-empirical compilation of Victoreen, as our theoretical understanding of the constituent Compton scattering, photoabsorption and pair production interactions of photons with atoms became more quantitative. The 1950s saw the advent of completely theoretical (guided by available measured data) systematic compilations such as in the works of Davisson and Evans, and by White-Grodstein under the direction of Fano, using mostly theory developed in the 1930s (pre-World War II) by Sauter, Bethe, Heitler and others. Post-World War II new theoretical activity, and the introduction of the electronic automatic computer, led to the more extensive and more accurate compilations in the 1960s and 1970s by Storm and Israel, and by Berger and Hubbell. Today's μ/ρ compilations by Cullen et al, by Seltzer, Berger and Hubbell, and by others, collectively spanning the ten decades of photon energy from 10 eV to 100 GeV, for all elements Z= 1 to 100, draw heavily on the 1970s shell-by-shell photoabsorption computations of Scofield, the 1960s coherent and incoherent scattering computations of Cromer et al, and the 1980 computations of electron-positron pair and triplet computations of Hubbell, Gimm and Øverbø, these names being representative of the vast legions of other researchers whose work fed into these computations. Work supported by the National Institute of Standards and Technology.

What happened to the HIV epidemic among non-injecting drug users in New York City?

PubMed

Des Jarlais, Don C; Arasteh, Kamyar; McKnight, Courtney; Feelemyer, Jonathan; Campbell, Aimee N C; Tross, Susan; Cooper, Hannah L F; Hagan, Holly; Perlman, David C

2017-02-01

HIV has reached high prevalence in many non-injecting drug user (NIDU) populations. The aims of this study were to (1) examine the trend in HIV prevalence among non-injecting cocaine and heroin NIDUs in New York City, (2) identify factors potentially associated with the trend and (3) estimate HIV incidence among NIDUs. Serial-cross sectional surveys of people entering drug treatment programs. People were permitted to participate only once per year, but could participate in multiple years. Mount Sinai Beth Israel drug treatment programs in New York City, USA. We recruited 3298 non-injecting cocaine and heroin users from 2005 to 2014. Participants were 78.7% male, 6.1% white, 25.7% Hispanic and 65.8% African American. Smoking crack cocaine was the most common non-injecting drug practice. Trend tests were used to examine HIV prevalence, demographics, drug use, sexual behavior and use of antiretroviral treatment (ART) by calendar year; χ 2 and multivariable logistic regression were used to compare 2005-10 versus 2011-14. HIV prevalence declined approximately 1% per year (P < 0.001), with a decline from 16% in 2005-10 to 8% in 2011-14 (P < 0.001). The percentages of participants smoking crack and having multiple sexual partners declined and the percentage of HIV-positive people on ART increased. HIV incidence among repeat participants was 1.2 per 1000 person-years (95% confidence interval = 0.03/1000-7/1000). HIV prevalence has declined and a high percentage of HIV-positive non-injecting drug users (NIDUs) are receiving antiretroviral treatment, suggesting an end to the HIV epidemic among NIDUs in New York City. These results can be considered a proof of concept that it is possible to control non-injecting drug use related sexual transmission HIV epidemics. © 2016 Society for the Study of Addiction.

Proton-Nucleus Elastic Cross Sections Using Two-Body In-Medium Scattering Amplitudes

NASA Technical Reports Server (NTRS)

Tripathi, R. K.; Wilson, John W.; Cucinotta, Francis A.

2001-01-01

Recently, a method was developed of extracting nucleon-nucleon (NN) cross sections in the medium directly from experiment. The in-medium NN cross sections form the basic ingredients of several heavy-ion scattering approaches including the coupled-channel approach developed at the Langley Research Center. The ratio of the real to the imaginary part of the two-body scattering amplitude in the medium was investigated. These ratios are used in combination with the in-medium NN cross sections to calculate elastic proton-nucleus cross sections. The agreement is excellent with the available experimental data. These cross sections are needed for the radiation risk assessment of space missions.

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

Singh, Suvam; Naghma, Rahla; Kaur, Jaspreet

The total and ionization cross sections for electron scattering by benzene, halobenzenes, toluene, aniline, and phenol are reported over a wide energy domain. The multi-scattering centre spherical complex optical potential method has been employed to find the total elastic and inelastic cross sections. The total ionization cross section is estimated from total inelastic cross section using the complex scattering potential-ionization contribution method. In the present article, the first theoretical calculations for electron impact total and ionization cross section have been performed for most of the targets having numerous practical applications. A reasonable agreement is obtained compared to existing experimental observationsmore » for all the targets reported here, especially for the total cross section.« less

Temperature dependence of the HNO3 UV absorption cross sections

NASA Technical Reports Server (NTRS)

Burkholder, James B.; Talukdar, Ranajit K.; Ravishankara, A. R.; Solomon, Susan

1993-01-01

The temperature dependence of the HNO3 absorption cross sections between 240 and 360 K over the wavelength range 195 to 350 nm has been measured using a diode array spectrometer. Absorption cross sections were determined using both (1) absolute pressure measurements at 298 K and (2) a dual absorption cell arrangement in which the absorption spectrum at various temperatures is measured relative to the room temperature absorption spectrum. The HNO3 absorption spectrum showed a temperature dependence which is weak at short wavelengths but stronger at longer wavelengths which are important for photolysis in the lower stratosphere. The 298 K absorption cross sections were found to be larger than the values currently recommended for atmospheric modeling (DeMore et al., 1992). Our absorption cross section data are critically compared with the previous measurements of both room temperature and temperature-dependent absorption cross sections. Temperature-dependent absorption cross sections of HNO3 are recommended for use in atmospheric modeling. These temperature dependent HNO3 absorption cross sections were used in a two-dimensional dynamical-photochemical model to demonstrate the effects of the revised absorption cross sections on loss rate of HNO3 and the abundance of NO2 in the stratosphere.

Cross sections for direct and dissociative ionization of NH3 and CS2 by electron impact

NASA Technical Reports Server (NTRS)

Rao, M. V. V. S.; Srivastava, S. K.

1991-01-01

A crossed electron beam-molecular beam collision geometry is used to measure cross sections for the production of positive ions by electron impact on NH3 and CS2. Ionization cross-section data for NH3 and the values of various cross sections are presented, as well as ionization efficiency curves for CS2. Considerable differences are found between the various results on NH3. The present values are close to the data of Djuric et al. (1981). The semiempirical calculations of Hare and Meath (1987) differ considerably in the absolute values of cross sections. Discrepancies were observed in comparisons of cross sections of other fragment ions resulting from the ionization and dissociate ionization of NH3.

Nuclear Forensics and Radiochemistry: Cross Sections

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

Rundberg, Robert S.

The neutron activation of components in a nuclear device can provide useful signatures of weapon design or sophistication. This lecture will cover some of the basics of neutron reaction cross sections. Nuclear reactor cross sections will also be presented to illustrate the complexity of convolving neutron energy spectra with nuclear excitation functions to calculate useful effective reactor cross sections. Deficiencies in the nuclear database will be discussed along with tools available at Los Alamos to provide new neutron cross section data.

Fragmentation Cross Sections of Medium-Energy 35Cl, 40Ar, and 48TiBeams on Elemental Targets

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

Zeitlin, C.; Guetersloh, S.; Heilbronn, L.

Charge-changing and fragment production cross sections at 0degrees have been obtained for interactions of 290, 400, and 650MeV/nucleon 40Ar beams, 650 and 1000 MeV/nucleon 35Cl beams, and a 1000MeV/nucleon 48Ti beam. Targets of C, CH2, Al, Cu, Sn, and Pb were used.Using standard analysis methods, we obtain fragment cross sections forcharges as low as 8 for Cl and Ar beams, and as low as 10 for the Tibeam. Using data obtained with small-acceptance detectors, we reportfragment production cross sections for charges as low as 5, corrected foracceptance using a simple model of fragment angular distributions. Withthe lower-charged fragment cross sections,more » we cancompare the data topredictions from several models (including NUCFRG2, EPAX2, and PHITS) ina region largely unexplored in earlier work. As found in earlier workwith other beams, NUCFRG2 and PHITS predictions agree reasonably wellwith the data for charge-changing cross sections, but do not accuratelypredict the fragment production cross sections. The cross sections forthe lightest fragments demonstrate the inadequacy of several models inwhich the cross sections fall monotonically with the charge of thefragment. PHITS, despite not agreeing particularly well with the fragmentproduction cross sections on average, nonetheless qualitativelyreproduces somesignificant features of the data that are missing from theother models.« less

Cross section and γ-ray spectra for U238(n,γ) measured with the DANCE detector array at the Los Alamos Neutron Science Center

NASA Astrophysics Data System (ADS)

Ullmann, J. L.; Kawano, T.; Bredeweg, T. A.; Couture, A.; Haight, R. C.; Jandel, M.; O'Donnell, J. M.; Rundberg, R. S.; Vieira, D. J.; Wilhelmy, J. B.; Becker, J. A.; Chyzh, A.; Wu, C. Y.; Baramsai, B.; Mitchell, G. E.; Krtička, M.

2014-03-01

Background: Accurate knowledge of the U238(n,γ) cross section is important for developing theoretical nuclear reaction models and for applications. However, capture cross sections are difficult to calculate accurately and often must be measured. Purpose: We seek to confirm previous measurements and test cross-section calculations with an emphasis on the unresolved resonance region from 1 to 500 keV. Method: Cross sections were measured from 10 eV to 500 keV using the DANCE detector array at the LANSCE spallation neutron source. The measurements used a thin target, 48 mg/cm2 of depleted uranium. Gamma cascade spectra were also measured to provide an additional constraint on calculations. The data are compared to cross-section calculations using the code CoH3 and cascade spectra calculations made using the code dicebox. Results: This new cross-section measurement confirms the previous data. The measured gamma-ray spectra suggest the need for additional low-lying dipole strength in the radiative strength function. New Hauser-Feshbach calculations including this strength accurately predict the capture cross section without renormalization. Conclusions: The present cross-section data confirm previous measurements. Including additional low-lying dipole strength in the radiative strength function may lead to more accurate cross-section calculations in nuclei where <Γγ> has not been measured.

High resolution absorption cross sections in the transmission window region of the Schumann-Runge bands and Herzberg continuum of O2

NASA Technical Reports Server (NTRS)

Yoshino, K.; Esmond, J. R.; Cheung, A. S.-C.; Freeman, D. E.; Parkinson, W. H.

1992-01-01

Results are presented on measurements, conducted in the wavelength region 180-195 nm, and at different pressures of oxygen (between 2.5-760 torr) in order to separate the pressure-dependent absorption from the main cross sections, of the absorption cross sections of the Schumann-Runge bands in the window region between the rotational lines of S-R bands of O2. The present cross sections supersede the earlier published cross sections (Yoshino et al., 1983). The combined cross sections are presented graphically; they are available at wavenumber intervals of about 0.1/cm from the National Space Science Data Center. The Herzberg continuum cross sections are derived after subtracting calculated contributions from the Schumann-Runge bands. These are significantly smaller than any previous measurements.

CEPXS

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

2015-10-19

CEPXS is a multigroup-Legendre cross-section generating code. The cross sections produced by CEPXS enable coupled electron-photon transport calculations to be performed with multigroup radiation transport codes, e.g. MITS and SCEPTRE. CEPXS generates multigroup-Legendre cross sections for photons, electrons and positrons over the energy range from 100 MeV to 1.0 keV. The continuous slowing-down approximation is used for those electron interactions that result in small-energy losses. The extended transport correction is applied to the forward-peaked elastic scattering cross section for electrons. A standard multigroup-Legendre treatment is used for the other coupled electron-photon cross sections. CEPXS extracts electron cross-section information from themore » DATAPAC data set and photon cross-section information from Biggs-Lighthill data. The model that is used for ionization/relaxation in CEPXS is essentially the same as that employed in ITS.« less

Partial Photoneutron Cross Sections for 207,208Pb

NASA Astrophysics Data System (ADS)

Kondo, T.; Utsunomiya, H.; Goriely, S.; Iwamoto, C.; Akimune, H.; Yamagata, T.; Toyokawa, H.; Harada, H.; Kitatani, F.; Lui, Y.-W.; Hilaire, S.; Koning, A. J.

2014-05-01

Using linearly-polarized laser-Compton scattering γ-rays, partial E1 and M1 photoneutron cross sections along with total cross sections were determined for 207,208Pb at four energies near neutron threshold by measuring anisotropies in photoneutron emission. Separately, total photoneutron cross sections were measured for 207,208Pb with a high-efficiency 4π neutron detector. The partial cross section measurement provides direct evidence for the presence of pygmy dipole resonance (PDR) in 207,208Pb in the vicinity of neutron threshold. The strength of PDR amounts to 0.32%-0.42% of the Thomas-Reiche-Kuhn sum rule. Several μN2 units of B(M1)↑ strength were observed in 207,208Pb just above neutron threshold, which correspond to M1 cross sections less than 10% of the total photoneutron cross sections.

Geologic Cross Section D-D' Through the Appalachian Basin from the Findlay Arch, Sandusky County, Ohio, to the Valley and Ridge Province, Hardy County, West Virginia

USGS Publications Warehouse

Ryder, Robert T.; Crangle, Robert D.; Trippi, Michael H.; Swezey, Christopher S.; Lentz, Erika E.; Rowan, Elisabeth L.; Hope, Rebecca S.

2009-01-01

Geologic cross section D-D' is the second in a series of cross sections constructed by the U.S. Geological Survey to document and improve understanding of the geologic framework and petroleum systems of the Appalachian basin. Cross section D-D' provides a regional view of the structural and stratigraphic framework of the Appalachian basin from the Findlay arch in northwestern Ohio to the Valley and Ridge province in eastern West Virginia, a distance of approximately 290 miles. The information shown on the cross section is based on geological and geophysical data from 13 deep drill holes, several of which penetrate the Paleozoic sedimentary rocks of the basin and bottom in Mesoproterozoic (Grenville-age) crystalline basement rocks. This cross section is a companion to cross section E-E' (Ryder and others, 2008) that is located about 25 to 50 mi to the southwest. Although specific petroleum systems in the Appalachian basin are not identified on the cross section, many of their key elements (such as source rocks, reservoir rocks, seals, and traps) can be inferred from lithologic units, unconformities, and geologic structures shown on the cross section. Other aspects of petroleum systems (such as the timing of petroleum generation and preferred migration pathways) may be evaluated by burial history, thermal history, and fluid flow models based on information shown on the cross section. Cross section D-D' lacks the detail to illustrate key elements of coal systems (such as paleoclimate, coal quality, and coal rank), but it does provide a general geologic framework (stratigraphic units and general rock types) for the coal-bearing section. Also, cross section D-D' may be used as a reconnaissance tool to identify plausible geologic structures and strata for the subsurface storage of liquid waste or for the sequestration of carbon dioxide.

Electron impact excitation of SO2 - Differential, integral, and momentum transfer cross sections

NASA Technical Reports Server (NTRS)

Vuskovic, L.; Trajmar, S.

1982-01-01

Electron impact excitation of the electronic states of SO2 was investigated. Differential, integral, and inelastic momentum transfer cross sections were obtained by normalizing the relative measurements to the elastic cross sections. The cross sections are given for seven spectral ranges of the energy-loss spectra extending from the lowest electronic state to near the first ionization limit. Most of the regions represent the overlap of several electronic transitions. No measurements for these cross sections have been reported previously.

Ohio Army National Guard Mental Health Initiative: Risk and Resilience Factors for Combat-Related Posttraumatic Psychopathology and Post Combat Adjustment

DTIC Science & Technology

2011-10-01

Goldmann, M.P.H., Edwin Shirley, Ph.D., Thomas Fine, M.A., Toyomi Goto, M.A., Kimberly Wilson, MSW, Stephen Ganocy, Ph.D., Philip Chan, M.S., Alphonse ...Kimberly Wilson, MSW, Stephen Ganocy, Ph.D., Philip Chan, M.S., Alphonse Derus, B.S., Mary Beth Serrano, M.A., Sandro Galea, M.D. Literature

A Determination of the Rate of Change of G

DTIC Science & Technology

1975-02-01

the gravitational constant; to Professor Sir Fred Hoyle and Mr Leslie Morrison, whose papers showed how gravitational acceleration could be...The observed rate is also consistent with the Dirac and the Hoyle - Narlikar cosmological theories, and to a lesser degree, with the Brans-Dicke...the expansion. Indeed, at least three currently plausible cosmological theories, Brans-Dicke (1961), Hoyle -Narlikar (1972), and Dirac (1973), demand

Partners with a Purpose: District and Teachers Union Ccreate an Evaluation System That Nurtures Professional Growth

ERIC Educational Resources Information Center

Pham, Kathleen; Heinemann, Amanda

2014-01-01

What is--or should be--the purpose of a teacher evaluation system? To compare teachers? To inform the public? To help teachers improve? Legislators might say that a teacher evaluation system's purpose is to remove bad teachers. Administrators might say that it is to assist them in matching teacher skills to specific groups of students. Parents…

Drug Abuse Treatment and Prevention--1984. Hearing before the Select Committee on Narcotics Abuse and Control. House of Representatives, Ninety-Eighth Congress, Second Session.

ERIC Educational Resources Information Center

Congress of the U.S., Washington, DC. House Select Committee on Narcotics Abuse and Control.

This document contains testimony and prepared statements from assistant secretaries in the Department of Education and the Department of Health and Human Services; directors from the Department of Health and Human Services; the general director of Beth Israel Medical Center; the president of Phoenix House Foundation, Inc., a drug-free treatment…

Shared Information Framework and Technology (SHIFT) Handbook

DTIC Science & Technology

2009-02-01

field. Such a patchwork of separate systems neither improves information sharing nor guarantees the safety and security of communities and personnel in...analysis. In many organizations, security may not necessarily be the expertise of people working in the field, or security and safety issues may be...the safety and security of all crisis management personnel in crisis areas. Functioning information sharing between organisations improves situational

Cultivating Culturally Fluent Leaders for the Future of Kinesiology. 2016 NAKHE Hally Beth Poindexter Young Scholar Award

ERIC Educational Resources Information Center

James-Hassan, Martha J.

2016-01-01

This article posits that each content area that falls under the umbrella of kinesiology must develop a future cadre of professionals who are competent in their content knowledge and are trained as leaders who are able to understand the essential impacts of culture on their work. The intentional development of culturally fluent leaders should be a…

Early Results on Activations and the Earnings of Reservists

DTIC Science & Technology

2005-01-01

compensation for the additional inconvenience, effort, and danger of such deployments. In the language of labor economics , they could be viewed as...Draft Lottery: Evidence from Social Security Administrative Records,” American Economic Review, June 1990, reprinted in Labor Economics , O. Ashenfelter... Labor Economics , January 1994. Asch, Beth J., and James R. Hosek. 1999. Military Compensation: Trends and Policy Options. Santa Monica, CA: RAND

Functions Character

NASA Astrophysics Data System (ADS)

Dugave, Maxime; Göhmann, Frank; Kozlowski, Karol Kajetan

2014-04-01

We establish several properties of the solutions to the linear integral equations describing the infinite volume properties of the XXZ spin-1/2 chain in the disordered regime. In particular, we obtain lower and upper bounds for the dressed energy, dressed charge and density of Bethe roots. Furthermore, we establish that given a fixed external magnetic field (or a fixed magnetization) there exists a unique value of the boundary of the Fermi zone.

Turnable Blue-Green LIDAR Transmitter Demonstration: Injection Laser Technology

DTIC Science & Technology

1990-08-30

5-1 5.2 Baseline Requirements ............................................. 5-1 5.3 Optical Parametric Oscillator Using Beta Barium Borate... optical parametric oscillators , and organic dye lasers. Tunable solid state lasers such as Ti: sapphire operate in the infrared and would have to be...The same is true of I frequency mixing schemes. Optical parametric oscillators (OPOs) are attractive because of their extremely wide potential tuning

Perspectives on Research in Artificial Intelligence and Artificial General Intelligence Relevant to DoD

DTIC Science & Technology

2017-01-01

3.2 Generic Network Architecture ........................................................................................ 11 3.3 Neuron Non ...The magnitude of the importance of these technologies is hard to overstate, and we thus feel that technically minded, non -expert readers should be...The result is often billions of weights and biases which need to be calculated. 13 3.3 Neuron Non -Linearity The big, early advance in

Effective mass of elementary excitations in Galilean-invariant integrable models

DOE PAGES

Matveev, K. A.; Pustilnik, M.

2016-09-27

Here, we study low-energy excitations of one-dimensional Galilean-invariant models integrable by Bethe ansatz and characterized by nonsingular two-particle scattering phase shifts. We also prove that the curvature of the excitation spectra is described by the recently proposed phenomenological expression for the effective mass. These results apply to such models as the repulsive Lieb-Liniger model and the hyperbolic Calogero-Sutherland model.

Pakistan-U.S. Relations

DTIC Science & Technology

2008-05-30

blocking terrorist financing.148 Top U.S. officials regularly praise Pakistani anti-terrorism efforts. In a landmark January 2002 speech , President...the speech , thousands of Muslim extremists were detained, CRS-41 149 “Musharraf: Bhutto Knew of Risks” (interview), CBS News, January 6, 2008. 150...and Mary Beth Nikitin. 206 Speech at the Carnegie Endowment for International Peace, Washington, DC, October 24, 2006. of lying low, resume their

Study of RE-garnets using BPW method

NASA Astrophysics Data System (ADS)

Goveas, Neena; Mukhopadhyay, P.; Mukhopadhyay, G.

1995-02-01

The magnetic susceptibility of rare-earth (Y and Lu) iron garnets is studied using a modified Bethe-Peierls-Weiss (BPW) approximation. The modifications enable us to incorporate the three exchange parameters Jad, Jaa and Jdd necessary to describe the systems. We get excellent fits to the experimental susceptibilities from which we determined the J-values. These also give excellent agreement with the spin wave dispersion relation constant D.

Effect of Load Carriage on Lumbar Spine Kinematics

DTIC Science & Technology

2013-01-01

reference frame and lordosis was reduced during all tasks with load. Superior levels became more lordotic, whereas inferior levels became more... lordosis , and IVD compressibility have been measured in both young 17 and adult 13 populations using upright MRI. However, these data cannot be...the kinematic behavior of the overall lumbar spine and func- tional spinal units. We hypothesized that IVD compression and lumbar lordosis increased

75 FR 62132 - Change in Bank Control Notices; Acquisitions of Shares of a Bank or Bank Holding Company

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-07

... Simmons, San Benito, Texas; and Leonard P. Simmons and Mary Beth Simmons, San Benito, Texas, Delores M... FEDERAL RESERVE SYSTEM Change in Bank Control Notices; Acquisitions of Shares of a Bank or Bank.... 1817(j)) and Sec. 225.41 of the Board's Regulation Y (12 CFR 225.41) to acquire shares of a bank or...

Proton-Nucleus Total Cross Sections in Coupled-Channel Approach

NASA Technical Reports Server (NTRS)

Tripathi, R. K.; Wilson, John W.; Cucinotta, Francis A.

2000-01-01

Recently, nucleon-nucleon (N-N) cross sections in the medium have been extracted directly from experiment. The in-medium N-N cross sections form the basic ingredients of several heavy-ion scattering approaches including the coupled-channel approach developed at the Langley Research Center. In the present study the ratio of the real to the imaginary part of the two-body scattering amplitude in the medium was investigated. These ratios are used in combination with the in-medium N-N cross sections to calculate total proton-nucleus cross sections. The agreement is excellent with the available experimental data. These cross sections are needed for the radiation risk assessment of space missions.

Electron impact scattering study of hypohalous acids HOX (X = F, Cl, Br, I)

NASA Astrophysics Data System (ADS)

Yadav, Hitesh; Bhutadia, Harshad; Prajapati, Dinesh; Desai, Hardik; Vinodkumar, Minaxi; Vinodkumar, P. C.

2018-05-01

In this article we aim to report total cross sections (TCS) QT, total elastic cross sections (Qel), total inelastic cross sections (Qinel) i.e. (total ionizations cross sections (Qion)+total electronic excitation cross sections (Qexc)) from threshold of the target to 5000 eV energy range. We have used a well-defined theoretical methodology Spherical Complex Optical Potential (SCOP) to compute QT, Qel and Qinel and Complex Scattering Potential - ionization contribution (CSP - ic) method to report the (Qion). The cross-sectional data reported here for the Hypohalous Acids is for the first time and the present data can become a guideline for the experimentalist to study these targets.

Rayleigh scattering cross sections of combustion species at 266, 355, and 532 nm for thermometry applications.

PubMed

Sutton, Jeffrey A; Driscoll, James F

2004-11-15

Rayleigh scattering cross sections are measured for nine combustion species (Ar, N2, O2, CO2, CO, H2, H2O, CH4, and C3H8) at wavelengths of 266, 355, and 532 nm and at temperatures ranging from 295 to 1525 K. Experimental results show that, as laser wavelengths become shorter, polarization effects become important and the depolarization ratio of the combustion species must be accounted for in the calculation of the Rayleigh scattering cross section. Temperature effects on the scattering cross section are also measured. Only a small temperature dependence is measured for cross sections at 355 nm, resulting in a 2-8% increase in cross section at temperatures of 1500 K. This temperature dependence increases slightly for measurements at 266 nm, resulting in a 5-11% increase in cross sections at temperatures of 1450 K.

Cross sections for n+{sup 14}N from an R-matrix analysis of the {sup 15}N system

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

Hale, G.M.; Young, P.G.; Chadwick, M.B.

1994-06-01

As part of the Hiroshima-Nagasaki Dose Reevaluation Program, a new evaluation of the neutron cross sections for {sup 14}N was made for ENDF/B-VI, based at energies below 2.5 MeV on a multichannel R-matrix analysis of reactions in the {sup 15}N system. The types of data used in the analysis, and the resulting cross sections and resonance structure for {sup 15}N are briefly described. The resonant features of the neutron cross sections were especially well determined by including precise, high-resolution neutron total cross section measurements from ORNL. While the new evaluated cross section appear to be significant improvements over the earliermore » ones, they still need to be tested more extensively against recent measurements of the differential elastic cross section from Oak Ridge.« less

Electron impact cross sections for the 2,2P state excitation of lithium

NASA Technical Reports Server (NTRS)

Vuskovic, L.; Trajmar, S.; Register, D. F.

1982-01-01

Electron impact excitation of the 2p 2P state of Li was studied at 10, 20, 60, 100, 150 and 200 eV. Relative differential cross sections in the angular range 3-120 deg were measured and then normalized to the absolute scale by using the optical f value. Integral and momentum transfer cross sections were obtained by extrapolating the differential cross sections to 0 deg and to 180 deg. The question of normalizing electron-metal-atom collision cross sections in general was examined and the method of normalization to optical f values in particular was investigated in detail. It has been concluded that the extrapolation of the apparent generalized oscillator strength (obtained from the measured differential cross sections) to the zero momentum transfer limit with an expression using even powers of the momentum transfer and normalization of the limit to the optical f value yields reliable absolute cross sections.

The 75As(n,2n) Cross Sections into the 74As Isomer and Ground State

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

Younes, W; Garrett, P E; Becker, J A

2003-06-30

The {sup 75}As(n, 2n) cross section for the population of the T{sub 1/2} = 26.8-ns isomer at E{sub x} = 259.3 keV in {sup 74}As has been measured as a function of incident neutron energy, from threshold to E{sub n} = 20 MeV. The cross section was measured using the GEANIE spectrometer at LANSCE/WNR. For convenience, the {sup 75}As(n, 2n) population cross section for the {sup 74}As ground state has been deduced as the difference between the previously-known (n, 2n) reaction cross section and the newly measured {sup 75}As(n, 2n){sup 74}As{sup m} cross section. The (n, 2n) reaction, ground-state, andmore » isomer population cross sections are tabulated in this paper.« less

Total and partial photoneutron cross sections for Pb isotopes

NASA Astrophysics Data System (ADS)

Kondo, T.; Utsunomiya, H.; Goriely, S.; Daoutidis, I.; Iwamoto, C.; Akimune, H.; Okamoto, A.; Yamagata, T.; Kamata, M.; Itoh, O.; Toyokawa, H.; Lui, Y.-W.; Harada, H.; Kitatani, F.; Hilaire, S.; Koning, A. J.

2012-07-01

Using quasimonochromatic laser-Compton scattering γ rays, total photoneutron cross sections were measured for 206,207,208Pb near neutron threshold with a high-efficiency 4π neutron detector. Partial E1 and M1 photoneutron cross sections along with total cross sections were determined for 207,208Pb at four energies near threshold by measuring anisotropies in photoneutron emission with linearly polarized γ rays. The E1 strength dominates over the M1 strength in the neutron channel where E1 photoneutron cross sections show extra strength of the pygmy dipole resonance in 207,208Pb near the neutron threshold corresponding to 0.32%-0.42% of the Thomas-Reiche-Kuhn sum rule. Several μN2 units of B(M1)↑ strength were observed in 207,208Pb just above neutron threshold, which correspond to an M1 cross section less than 10% of the total photoneutron cross section.

Mental Visualization of Objects from Cross-Sectional Images

ERIC Educational Resources Information Center

Wu, Bing; Klatzky, Roberta L.; Stetten, George D.

2012-01-01

We extended the classic anorthoscopic viewing procedure to test a model of visualization of 3D structures from 2D cross-sections. Four experiments were conducted to examine key processes described in the model, localizing cross-sections within a common frame of reference and spatiotemporal integration of cross sections into a hierarchical object…

Viscous Flow through Pipes of Various Cross-Sections

ERIC Educational Resources Information Center

Lekner, John

2007-01-01

An interesting variety of pipe cross-sectional shapes can be generated, for which the Navier-Stokes equations can be solved exactly. The simplest cases include the known solutions for elliptical and equilateral triangle cross-sections. Students can find pipe cross-sections from solutions of Laplace's equation in two dimensions, and then plot the…

Activation cross section and isomeric cross section ratio for the 76Ge(n,2n)75m,gGe process

NASA Astrophysics Data System (ADS)

Luo, Junhua; Jiang, Li; Wang, Xinxing

2018-04-01

We measured neutron-induced reaction cross sections for the 76Ge(n,2n)75m,gGe reactions and their isomeric cross section ratios σm/σg at three neutron energies between 13 and 15MeV by an activation and off-line γ-ray spectrometric technique using the K-400 Neutron Generator at the Chinese Academy of Engineering Physics (CAEP). Ge samples and Nb monitor foils were activated together to determine the reaction cross section and the incident neutron flux. The monoenergetic neutron beams were formed via the 3H( d, n)4He reaction. The pure cross section of the ground state was derived from the absolute cross section of the metastable state and the residual nuclear decay analysis. The cross sections were also calculated using the nuclear model code TALYS-1.8 with different level density options at neutron energies varying from the reaction threshold to 20MeV. Results are discussed and compared with the corresponding literature data.

O2 absorption cross sections /187-225 nm/ from stratospheric solar flux measurements

NASA Technical Reports Server (NTRS)

Herman, J. R.; Mentall, J. E.

1982-01-01

The absorption cross sections of molecular oxygen are calculated in the wavelength range from 187 to 230 nm from solar flux measurements obtained within the stratosphere. Within the Herzberg continuum wavelength region the molecular oxygen cross sections are found to be about 30% smaller than the laboratory results of Shardanand and Rao (1977) from 200 to 210 nm and about 50% smaller than those of Hasson and Nicholls (1971). At wavelengths longer than 210 nm the cross sections agree with those of Shardanand and Rao. The effective absorption cross sections of O2 in the Schumann-Runge band region from 187 to 200 nm are calculated and compared to the empirical fit given by Allen and Frederick (1982). The calculated cross sections indicate that the transmissivity of the atmosphere may be underestimated by the use of the Allen and Frederic cross sections between 195 and 200 nm. The ozone column content between 30 and 40 km and the relative ozone cross sections are determined from the same solar flux data set.

Using thermochonology to validate a balanced cross section along the Karnali River, far-western Nepal

NASA Astrophysics Data System (ADS)

Battistella, C.; Robinson, D.; McQuarrie, N.; Ghoshal, S.

2017-12-01

Multiple valid balanced cross sections can be produced from mapped surface and subsurface data. By integrating low temperature thermochronologic data, we are better able to predict subsurface geometries. Existing valid balanced cross section for far western Nepal are few (Robinson et al., 2006) and do not incorporate thermochronologic data because the data did not exist. The data published along the Simikot cross section along the Karnali River since then include muscovite Ar, zircon U-Th/He and apatite fission track. We present new mapping and a new valid balanced cross section that takes into account the new field data as well as the limitations that thermochronologic data places on the kinematics of the cross section. Additional constrains include some new geomorphology data acquired since 2006 that indicate areas of increased vertical uplift, which indicate locations of buried ramps in the Main Himalayan thrust and guide the locations of Lesser Himalayan ramps in the balanced cross section. Future work will include flexural modeling, new low temperature thermochronometic data, and 2-D thermokinematic models from a sequentially forward modeled balanced cross sections in far western Nepal.

Scattered light and accuracy of the cross-section measurements of weak absorptions: Gas and liquid phase UV absorption cross sections of CH3CFCl2

NASA Technical Reports Server (NTRS)

Fahr, A.; Braun, W.; Kurylo, M. J.

1993-01-01

Ultraviolet absorption cross sections of CH3CFCl2(HCFC-141b) were determined in the gas phase (190-260 nm) and liquid phase (230-260 mm) at 298 K. The liquid phase absorption cross sections were then converted into accurate gas phase values using a previously described procedure. It has been demonstrated that scattered light from the shorter-wavelength region (as little as several parts per thousand) can seriously compromise the absorption cross-section measurement, particularly at longer wavelengths where cross sections are low, and can be a source of discrepancies in the cross sections of weakly absorbing halocarbons reported in the literature. A modeling procedure was developed to assess the effect of scattered light on the measured absorption cross section in our experiments, thereby permitting appropriate corrections to be made on the experimental values. Modeled and experimental results were found to be in good agreement. Experimental results from this study were compared with other available determinations and provide accurate input for calculating the atmospheric lifetime of HCFC-141b.

Low-energy proton induced M X-ray production cross sections for 70Yb, 81Tl and 82Pb

NASA Astrophysics Data System (ADS)

Shehla; Mandal, A.; Kumar, Ajay; Roy Chowdhury, M.; Puri, Sanjiv; Tribedi, L. C.

2018-07-01

The cross sections for production of Mk (k = Mξ, Mαβ, Mγ, Mm1) X-rays of 70Yb, 81Tl and 82Pb induced by 50-250 keV protons have been measured in the present work. The experimental cross sections have been compared with the earlier reported values and those calculated using the ionization cross sections based on the ECPSSR (Perturbed (P) stationary(S) state(S), incident ion energy (E) loss, Coulomb (C) deflection and relativistic (R) correction) model, the X-ray emission rates based on the Dirac-Fock model, the fluorescence and Coster-Kronig yields based on the Dirac-Hartree-Slater (DHS) model. In addition, the present measured proton induced X-ray production cross sections have also been compared with those calculated using the Dirac-Hartree-Slater (DHS) model based ionization cross sections and those based on the Plane wave Born Approximation (PWBA). The measured M X-ray production cross sections are, in general, found to be higher than the ECPSSR and DHS model based values and lower than the PWBA model based cross sections.

Positron induced scattering cross sections for hydrocarbons relevant to plasma

NASA Astrophysics Data System (ADS)

Singh, Suvam; Antony, Bobby

2018-05-01

This article explores positron scattering cross sections by simple hydrocarbons such as ethane, ethene, ethyne, propane, and propyne. Chemical erosion processes occurring on the surface due to plasma-wall interactions are an abundant source of hydrocarbon molecules which contaminate the hydrogenic plasma. These hydrocarbons play an important role in the edge plasma region of Tokamak and ITER. In addition to this, they are also one of the major components in the planetary atmospheres and astrophysical mediums. The present work focuses on calculation of different positron impact interactions with simple hydrocarbons in terms of the total cross section (Qtot), elastic cross section (Qel), direct ionization cross section (Qion), positronium formation cross section (Qps), and total ionization cross section (Qtion). Knowing that the positron-plasma study is one of the trending fields, the calculated data have diverse plasma and astrophysical modeling applications. A comprehensive study of Qtot has been provided where the inelastic cross sections have been reported for the first time. Comparisons are made with those available from the literature, and a good agreement is obtained with the measurements.

Electron induced inelastic and ionization cross section for plasma modeling

NASA Astrophysics Data System (ADS)

Verma, Pankaj; Mahato, Dibyendu; Kaur, Jaspreet; Antony, Bobby

2016-09-01

The present paper reports electron impact total inelastic and ionization cross section for silicon, germanium, and tin tetrahalides at energies varying from ionization threshold of the target to 5000 eV. These cross section data over a wide energy domain are very essential to understand the physico-chemical processes involved in various environments such as plasma modeling, semiconductor etching, atmospheric sciences, biological sciences, and radiation physics. However, the cross section data on the above mentioned molecules are scarce. In the present article, we report the computation of total inelastic cross section using spherical complex optical potential formalism and the estimation of ionization cross section through a semi-empirical method. The present ionization cross section result obtained for SiCl4 shows excellent agreement with previous measurements, while other molecules have not yet been investigated experimentally. Present results show more consistent behaviour than previous theoretical estimates. Besides cross sections, we have also studied the correlation of maximum ionization cross section with the square root of the ratio of polarizability to ionization potential for the molecules with known polarizabilities. A linear relation is observed between these quantities. This correlation is used to obtain approximate polarizability volumes for SiBr4, SiI4, GeCl4, GeBr4, and GeI4 molecules.

Breakup and fusion cross sections of the 6Li nucleus with targets of mass A = 58, 144 and 208

NASA Astrophysics Data System (ADS)

Mukeru, B.; Rampho, G. J.; Lekala, M. L.

2018-04-01

We use the continuum discretized coupled channels method to investigate the effects of continuum-continuum coupling on the breakup and fusion cross sections of the weakly bound 6Li nucleus with the 58Ni, 144Sm and 208Pb nuclear targets. The cross sections were analyzed at incident energies E cm below, close to and above the Coulomb barrier V B. We found that for the medium and heavy targets, the breakup cross sections are enhanced at energies below the Coulomb barrier (E cm/V B ≤ 0.8) owing to these couplings. For the lighter target, relatively small enhancement of the breakup cross sections appear at energies well below the barrier (E cm/V B ≤ 0.6). At energies E cm/V B > 0.8 for medium and heavy targets, and E cm/V B > 0.6 for the light target, the continuum-continuum couplings substantially suppress the breakup cross sections. On the other hand, the fusion cross sections are enhanced at energies E cm/V B < 1.4, E cm/V B < 1.2 and E cm/V B < 0.8 for the light, medium and heavy target, respectively. The enhancement decreases as the target mass increases. Above the indicated respective energies, these couplings suppress the fusion cross sections. We also compared the breakup and fusion cross sections, and found that below the barrier, the breakup cross sections are more dominant regardless of whether continuum-continuum couplings are included.

Simple, empirical approach to predict neutron capture cross sections from nuclear masses

NASA Astrophysics Data System (ADS)

Couture, A.; Casten, R. F.; Cakirli, R. B.

2017-12-01

Background: Neutron capture cross sections are essential to understanding the astrophysical s and r processes, the modeling of nuclear reactor design and performance, and for a wide variety of nuclear forensics applications. Often, cross sections are needed for nuclei where experimental measurements are difficult. Enormous effort, over many decades, has gone into attempting to develop sophisticated statistical reaction models to predict these cross sections. Such work has met with some success but is often unable to reproduce measured cross sections to better than 40 % , and has limited predictive power, with predictions from different models rapidly differing by an order of magnitude a few nucleons from the last measurement. Purpose: To develop a new approach to predicting neutron capture cross sections over broad ranges of nuclei that accounts for their values where known and which has reliable predictive power with small uncertainties for many nuclei where they are unknown. Methods: Experimental neutron capture cross sections were compared to empirical mass observables in regions of similar structure. Results: We present an extremely simple method, based solely on empirical mass observables, that correlates neutron capture cross sections in the critical energy range from a few keV to a couple hundred keV. We show that regional cross sections are compactly correlated in medium and heavy mass nuclei with the two-neutron separation energy. These correlations are easily amenable to predict unknown cross sections, often converting the usual extrapolations to more reliable interpolations. It almost always reproduces existing data to within 25 % and estimated uncertainties are below about 40 % up to 10 nucleons beyond known data. Conclusions: Neutron capture cross sections display a surprisingly strong connection to the two-neutron separation energy, a nuclear structure property. The simple, empirical correlations uncovered provide model-independent predictions of neutron capture cross sections, extending far from stability, including for nuclei of the highest sensitivity to r -process nucleosynthesis.

Kinematic Modeling of Central Nepal: Thermochronometer Cooling Ages as a Constraint for Balanced Cross Sections

NASA Astrophysics Data System (ADS)

Olree, E.; Robinson, D. M.; McQuarrie, N.; Ghoshal, S.; Olsen, J.

2016-12-01

Using balanced cross sections, one can visualize a valid and admissible interpretation of the surface and subsurface data. Khanal (2014) and Cross (2014) produced two valid and admissible cross sections along the Marsyandi River in central Nepal. However, thermochronologic data adds another dimension that must be adhered to when producing valid and admissible balanced cross sections. Since the previous cross sections were produced, additional zircon-helium (ZHe) cooling ages along the Marsyandi River show ages of 1 Ma near the Main Central thrust in the hinterland to 4 Ma near the Main Boundary thrust closer to the foreland. This distribution of cooling ages requires recent uplift in the hinterland, which is not present in the cross sections. Although a restored version of the Khanal (2014) cross section is sequentially deformed using 2D Move, the kinematic sequence implied in the cross section is inconsistent with the ZHe age distribution. The hinterland dipping duplex proposed by Khanal would require cooling ages that are oldest near the Main Central thrust and young southwards toward the active ramp located 80 km north of the Main Frontal thrust. Instead, the 4 Ma age near the Main Boundary thrust and the increasingly younger ages to the north could be produced by either a foreland-dipping Lesser Himalayan duplex, which would keep active uplift in the north, or by translation of the hinterland dipping duplex southward over the ramp, moving the active thrust ramp northward. To address this problem, a new balanced cross section was produced using both new mapping through the region and the ZHe age distribution as additional constraints. The section was then restored and sequentially deformed in 2D Move. This study illustrates that multiple cross sections can be viable and admissible; however, they can still be incorrect. Thermochronology places additional constraints on the permissible geometries, and thus increases our ability to predict subsurface geometries. The next step of this project is to link the uplift and erosion implied by the kinematic sequence of the new cross section to the measured cooling history by importing the cross section kinematics into advection diffusion modeling software that predicts cooling ages.

Fragmentation of Ar-40 at 100 GeV/c

NASA Technical Reports Server (NTRS)

Lindstrom, P. J.; Greiner, D. E.; Heckman, H. H.; Cork, B.; Bieser, F. S.

1975-01-01

The delta Z is greater than or equal to 1 reaction cross section for 1.8 GeV/n Ar-40 have been measured on targets ranging from H to Pb. Comparing these cross sections with H-1, C-12, and O-16 reaction cross sections at relativistic energies yields a formula for nucleus-nucleus reaction cross sections.

Temperature-dependent absorption cross sections for hydrogen peroxide vapor

NASA Technical Reports Server (NTRS)

Nicovich, J. M.; Wine, P. H.

1988-01-01

Relative absorption cross sections for hydrogen peroxide vapor were measured over the temperature ranges 285-381 K for lambda = 230 nm-295 nm and 300-381 K for lambda = 193 nm-350 nm. The well established 298 K cross sections at 202.6 and 228.8 nm were used as an absolute calibration. A significant temperature dependence was observed at the important tropospheric photolysis wavelengths lambda over 300 nm. Measured cross sections were extrapolated to lower temperatures, using a simple model which attributes the observed temperature dependence to enhanced absorption by molecules possessing one quantum of O-O stretch vibrational excitation. Upper tropospheric photodissociation rates calculated using the extrapolated cross sections are about 25 percent lower than those calculated using currently recommended 298 K cross sections.

Measurements of absolute absorption cross sections of ozone in the 185- to 254-nm wavelength region and the temperature dependence

NASA Technical Reports Server (NTRS)

Yoshino, K.; Esmond, J. R.; Freeman, D. E.; Parkinson, W. H.

1993-01-01

Laboratory measurements of the relative absorption cross sections of ozone at temperatures 195, 228, and 295 K have been made throughout the 185 to 254 nm wavelength region. The absolute absorption cross sections at the same temperatures have been measured at several discrete wavelengths in the 185 to 250 nm region. The absolute cross sections of ozone have been used to put the relative cross sections on a firm absolute basis throughout the 185 to 255 nm region. These recalibrated cross sections are slightly lower than those of Molina and Molina (1986), but the differences are within a few percent and would not be significant in atmospheric applications.

Fragmentation cross sections of O-16 between 0.9 and 200 GeV/nucleon

NASA Technical Reports Server (NTRS)

Hirzebruch, S. E.; Heinrich, W.; Tolstov, K. D.; Kovalenko, A. D.; Benton, E. V.

1995-01-01

Inclusive cross sections for high energy interactions at 0.9, 2.3, 3.6, and 13.5 GeV/nucleon of O-16 with C, CR-39 (C12H18O7), CH2, Al, Cu, Ag, and Pb targets were measured. The total charge-changing cross sections and partial charge-changing cross sections for the production of fragments with charge Z = 6 and Z = 7 are compared to previous experiments at 60 and 200 GeV/nucleon. The contributions of Coulomb dissociation to the total cross sections are calculated. Using factorization rules the partial electromagnetic cross sections are separated from the nuclear components. Energy dependence of both components are investigated and discussed.

Nuclear annihilation by antinucleons

DOE PAGES

Lee, Teck-Ghee; Wong, Cheuk-Yin

2016-01-25

We examine the momentum dependence ofmore » $$\\bar{p}$$p and $$\\bar{n}$$p annihilation cross sections by considering the transmission through a nuclear potential and the $$\\bar {p}$$p Coulomb interaction. Compared to the $$\\bar{n}$$p annihilation cross section, the $$\\bar{p}$$p annihilation cross section is significantly enhanced by the Coulomb interaction for projectile momenta below p lab < 500 MeV/c, and the two annihilation cross sections approach the Pomeranchuk's equality limit [JETP 30, 423 (1956)] at p lab ~500 MeV/c. Using these elementary cross sections as the basic input data, the extended Glauber model is employed to evaluate the annihilation cross sections for $$\\bar{n}$$ and $$\\bar{p}$$ interaction with nuclei and the results compare well with experimental data.« less

Using 171,173Yb(d,p) to benchmark a surrogate reaction for neutron capture

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

Hatarik, R; Bersntein, L; Burke, J

2008-08-08

Neutron capture cross sections on unstable nuclei are important for many applications in nuclear structure and astrophysics. Measuring these cross sections directly is a major challenge and often impossible. An indirect approach for measuring these cross sections is the surrogate reaction method, which makes it possible to relate the desired cross section to a cross section of an alternate reaction that proceeds through the same compound nucleus. To benchmark the validity of using the (d,p{gamma}) reaction as a surrogate for (n,{gamma}), the {sup 171,173}Yb(d,p{gamma}) reactions were measured with the goal to reproduce the known [1] neutron capture cross section ratiosmore » of these nuclei.« less

Photoeffect cross sections of several rare-earth elements for 323-keV photons

NASA Astrophysics Data System (ADS)

Umesh, T. K.; Anasuya, S. J.; Shylaja Kumari, J.; Gowda, Channe; Gopinathan Nair, K. P.; Gowda, Ramakrishna

1992-02-01

Total-attenuation cross sections of the oxides of rare-earth elements such as La, Ce, Pr, Nd, Sm, Gd, Dy, Ho, and Er, and also NaNO3 and NaNO2 have been measured in a narrow-beam geometry setup at 323 keV. The total-attenuation cross section for oxygen was obtained as the difference in NaNO3 and NaNO2 cross sections. Using this, the total-attenuation cross sections of the individual lanthanides have been obtained with the aid of the mixture rule. From these, the photoeffect cross sections were derived by subtracting the scattering contribution. These values are found to agree well with Scofield's theoretical data [University of California Report No. UCRL 51326, 1973 (unpublished)].

One-jet inclusive cross section at order a(s)-cubed - Gluons only

NASA Technical Reports Server (NTRS)

Ellis, Stephen D.; Kunszt, Zoltan; Soper, Davison E.

1989-01-01

A complete calculation of the hadron jet cross-section at one order beyond the Born approximation is performed for the simplified case in which there are only gluons. The general structure of the differences from the lowest-order cross-section are described. This step allows two important improvements in the understanding of the theoretical hadron jet cross-section: first, the cross section at this order displays explicit dependence on the jet cone size, so that explicit account can be taken of the differences in jet definitions employed by different experiments; second, the magnitude of the uncertainty of the theoretical cross-section due to the arbitrary choice of the factorization scale has been reduced by a factor of two to three.

Solid oxide fuel cell with transitioned cross-section for improved anode gas management at the open end

DOEpatents

Zafred, Paolo R [Murrysville, PA; Draper, Robert [Pittsburgh, PA

2012-01-17

A solid oxide fuel cell (400) is made having a tubular, elongated, hollow, active section (445) which has a cross-section containing an air electrode (452) a fuel electrode (454) and solid oxide electrolyte (456) between them, where the fuel cell transitions into at least one inactive section (460) with a flattened parallel sided cross-section (462, 468) each cross-section having channels (472, 474, 476) in them which smoothly communicate with each other at an interface section (458).

Integrability of the Ad{{S}_{5}}\\times {{S}^{5}} superstring and its deformations

NASA Astrophysics Data System (ADS)

van Tongeren, Stijn J.

2014-10-01

This article reviews the application of integrability to the spectral problem of strings on Ad{{S}5}× {{S}5} and its deformations. We begin with a pedagogical introduction to integrable field theories culminating in the description of their finite-volume spectra through the thermodynamic Bethe ansatz (TBA). Next, we apply these ideas to the Ad{{S}5}× {{S}5} string and in later sections discuss how to account for particular integrable deformations. Through the AdS/CFT correspondence this gives an exact description of anomalous scaling dimensions of single trace operators in planar N=4 supersymmetry Yang-Mills theory, its ‘orbifolds’, and β and γ-deformed supersymmetric Yang-Mills theory. We also touch upon some subtleties arising in these deformed theories. Furthermore, we consider complex excited states (bound states) in the su(2) sector and give their TBA description. Finally we discuss the TBA for a quantum deformation of the Ad{{S}5}× {{S}5} superstring S-matrix, with close relations to among others Pohlmeyer reduced string theory, and briefly indicate more recent developments in this area.

Nuclear reactor control column

DOEpatents

Bachovchin, Dennis M.

1982-01-01

The nuclear reactor control column comprises a column disposed within the nuclear reactor core having a variable cross-section hollow channel and containing balls whose vertical location is determined by the flow of the reactor coolant through the column. The control column is divided into three basic sections wherein each of the sections has a different cross-sectional area. The uppermost section of the control column has the greatest cross-sectional area, the intermediate section of the control column has the smallest cross-sectional area, and the lowermost section of the control column has the intermediate cross-sectional area. In this manner, the area of the uppermost section can be established such that when the reactor coolant is flowing under normal conditions therethrough, the absorber balls will be lifted and suspended in a fluidized bed manner in the upper section. However, when the reactor coolant flow falls below a predetermined value, the absorber balls will fall through the intermediate section and into the lowermost section, thereby reducing the reactivity of the reactor core and shutting down the reactor.

Fragmentation cross sections of medium-energy {sup 35}Cl, {sup 40}Ar, and {sup 48}Ti beams on elemental targets

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

Zeitlin, C.; Guetersloh, S.; Heilbronn, L.

Charge-changing and fragment production cross sections at 0 deg. have been obtained for interactions of 290, 400, and 650 MeV/nucleon {sup 40}Ar beams, 650 and 1000 MeV/nucleon {sup 35}Cl beams, and a 1000 MeV/nucleon {sup 48}Ti beam. Targets of C, CH{sub 2}, Al, Cu, Sn, and Pb were used. Using standard analysis methods, we obtained fragment cross sections for charges as low as 8 for Cl and Ar beams and as low as 10 for the Ti beam. Using data obtained with small-acceptance detectors, we report fragment production cross sections for charges as low as 5, corrected for acceptance usingmore » a simple model of fragment angular distributions. With the lower-charged fragment cross sections, we can compare the data to predictions from several models (including NUCFRG2, EPAX2, and PHITS) in a region largely unexplored in earlier work. As found in earlier work with other beams, NUCFRG2 and PHITS predictions agree reasonably well with the data for charge-changing cross sections, but these models do not accurately predict the fragment production cross sections. The cross sections for the lightest fragments demonstrate the inadequacy of several models in which the cross sections fall monotonically with the charge of the fragment. PHITS, despite its not agreeing particularly well with the fragment production cross sections on average, nonetheless qualitatively reproduces some significant features of the data that are missing from the other models.« less

Influence of strut cross-section of stents on local hemodynamics in stented arteries

NASA Astrophysics Data System (ADS)

Jiang, Yongfei; Zhang, Jun; Zhao, Wanhua

2016-05-01

Stenting is a very effective treatment for stenotic vascular diseases, but vascular geometries altered by stent implantation may lead to flow disturbances which play an important role in the initiation and progression of restenosis, especially in the near wall in stented arterial regions. So stent designs have become one of the indispensable factors needed to be considered for reducing the flow disturbances. In this paper, the structural designs of strut cross-section are considered as an aspect of stent designs to be studied in details. Six virtual stents with different strut cross-section are designed for deployments in the same ideal arterial model. Computational fluid dynamics (CFD) methods are performed to study how the shape and the aspect ratio (AR) of strut cross-section modified the local hemodynamics in the stented segments. The results indicate that stents with different strut cross-sections have different influence on the hemodynamics. Stents with streamlined cross-sectional struts for circular arc or elliptical arc can significantly enhance wall shear stress (WSS) in the stented segments, and reduce the flow disturbances around stent struts. The performances of stents with streamlined cross-sectional struts are better than that of stents with non-streamlined cross-sectional struts for rectangle. The results also show that stents with a larger AR cross-section are more conductive to improve the blood flow. The present study provides an understanding of the flow physics in the vicinity of stent struts and indicates that the shape and AR of strut cross-section ought to be considered as important factors to minimize flow disturbance in stent designs.

The Production of FRW Universe and Decay to Particles in Multiverse

NASA Astrophysics Data System (ADS)

Ghaffary, Tooraj

2017-09-01

In this study, first, it will be shown that as the Hubble parameter, " H", increases the production cross section for closed and flat Universes increases rapidly at smaller values of " H" and becomes constant for higher values of " H". However in the case of open Universe, the production cross section has been encountered a singularity. Before this singularity, as the H parameter increases, the cross section increases, for smaller H, ( H < 2.5), exhibits a turn-over at moderate values of H, (2.5 < H < 3.5), decreases for larger amount of H After that and for a special value of H, the cross section has been encountered with a singularity. Although the cross section cannot be defined at this singularity but before and after this point, it is certainly equal to zero. After this singularity, the cross section increases rapidly, when H increases. It is shown that if the production cross section of Universe happens before this singularity, it can't achieve to higher values of Hubble parameter after singularity. More over if the production cross section of Universe situates after the singularity, it won't get access to values of Hubble parameter less than the singularity. After that the thermal distribution for particles inside the FRW Universes are obtained. It is found that a large amount of particles are produced near apparent horizon due to their variety in their energy and their probabilities. Finally, comparing the particle production cross sections for flat, closed and open Universes, it is concluded that as the value of k increases, the cross section decreases.

Poster - 18: New features in EGSnrc for photon cross sections

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

Ali, Elsayed; Mainegra-Hing, Ernesto; Rogers, Davi

2016-08-15

Purpose: To implement two new features in the EGSnrc Monte Carlo system. The first is an option to account for photonuclear attenuation, which can contribute a few percent to the total cross section at the higher end of the energy range of interest to medical physics. The second is an option to use exact NIST XCOM photon cross sections. Methods: For the first feature, the photonuclear total cross sections are generated from the IAEA evaluated data. In the current, first-order implementation, after a photonuclear event, there is no energy deposition or secondary particle generation. The implementation is validated against deterministicmore » calculations and experimental measurements of transmission signals. For the second feature, before this work, if the user explicitly requested XCOM photon cross sections, EGSnrc still used its own internal incoherent scattering cross sections. These differ by up to 2% from XCOM data between 30 keV and 40 MeV. After this work, exact XCOM incoherent scattering cross sections are an available option. Minor interpolation artifacts in pair and triplet XCOM cross sections are also addressed. The default for photon cross section in EGSnrc is XCOM except for the new incoherent scattering cross sections, which have to be explicitly requested. The photonuclear, incoherent, pair and triplet data from this work are available for elements and compounds for photon energies from 1 keV to 100 GeV. Results: Both features are implemented and validated in EGSnrc.Conclusions: The two features are part of the standard EGSnrc distribution as of version 4.2.3.2.« less

Cross sections for H(-) and Cl(-) production from HCl by dissociative electron attachment

NASA Technical Reports Server (NTRS)

Orient, O. J.; Srivastava, S. K.

1985-01-01

A crossed target beam-electron beam collision geometry and a quadrupole mass spectrometer have been used to conduct dissociative electron attachment cross section measurements for the case of H(-) and Cl(-) production from HCl. The relative flow technique is used to determine the absolute values of cross sections. A tabulation is given of the attachment energies corresponding to various cross section maxima. Error sources contributing to total errors are also estimated.

Measurements of neutron capture cross sections on 70Zn at 0.96 and 1.69 MeV

NASA Astrophysics Data System (ADS)

Punte, L. R. M.; Lalremruata, B.; Otuka, N.; Suryanarayana, S. V.; Iwamoto, Y.; Pachuau, Rebecca; Satheesh, B.; Thanga, H. H.; Danu, L. S.; Desai, V. V.; Hlondo, L. R.; Kailas, S.; Ganesan, S.; Nayak, B. K.; Saxena, A.

2017-02-01

The cross sections of the 70Zn(n ,γ )Zn71m (T1 /2=3.96 ±0.05 -h ) reaction have been measured relative to the 197Au(n ,γ )198Au cross sections at 0.96 and 1.69 MeV using a 7Li(p ,n )7Be neutron source and activation technique. The cross section of this reaction has been measured for the first time in the MeV region. The new experimental cross sections have been compared with the theoretical prediction by talys-1.6 with various level-density models and γ -ray strength functions as well as the tendl-2015 library. The talys-1.6 calculation with the generalized superfluid level-density model and Kopecky-Uhl generalized Lorentzian γ -ray strength function predicted the new experimental cross sections at both incident energies. The 70Zn(n ,γ ) g+m 71Zn total capture cross sections have also been derived by applying the evaluated isomeric ratios in the tendl-2015 library to the measured partial capture cross sections. The spectrum averaged total capture cross sections derived in the present paper agree well with the jendl-4.0 library at 0.96 MeV, whereas it lies between the tendl-2015 and the jendl-4.0 libraries at 1.69 MeV.

Semi-empirical scaling for ion-atom single charge exchange cross sections in the intermediate velocity regime

NASA Astrophysics Data System (ADS)

Friedman, B.; DuCharme, G.

2017-06-01

We present a semi-empirical scaling law for non-resonant ion-atom single charge exchange cross sections for collisions with velocities from {10}7 {{t}}{{o}} {10}9 {cm} {{{s}}}-1 and ions with positive charge q< 8. Non-resonant cross sections tend to have a velocity peak at collision velocities v≲ 1 {{a}}{{u}} with exponential decay around this peak. We construct a scaling formula for the location of this peak then choose a functional form for the cross section curve and scale it. The velocity at which the cross section peaks, v m, is proportional to the energy defect of the collision, {{Δ }}E, which we predict with the decay approximation. The value of the cross section maximum is proportional to the charge state q, inversely proportional to the target ionization energy I T, and inversely proportional to v m. For the shape of the cross section curve, we use a function that decays exponentially asymptotically at high and low velocities. We scale this function with parameters {v}{{m}},{I}{{T}},{Z}{{T}},{and} {Z}{{P}}, where the {Z}{{T},{{P}}} are the target and projectile atomic numbers. For the more than 100 cross section curves that we use to find the scaling rules, the scaling law predicts cross sections within a little over a factor of 2 on average.

Sonographic evaluation of the greater occipital nerve in unilateral occipital neuralgia.

PubMed

Cho, John Chin-Suk; Haun, Daniel W; Kettner, Norman W

2012-01-01

Occipital neuralgia is a headache that may result from greater occipital nerve entrapment. Entrapped peripheral nerves typically have an increase in cross-sectional area. The purpose of this study was to measure the cross-sectional area and circumference of symptomatic and asymptomatic greater occipital nerves in patients with unilateral occipital neuralgia and to correlate the greater occipital nerve cross-sectional area with headache severity, sex, and body mass index. Both symptomatic and contralateral asymptomatic greater occipital nerve cross-sectional areas and circumferences were measured by a single examiner using sonography in 17 patients. The Wilcoxon signed rank test and Spearman rank order correlation coefficient were used to analyze the data. Significant differences between the cross-sectional areas and circumferences of the symptomatic and asymptomatic greater occipital nerves were noted (P < .001). No difference existed in cross-sectional area (P = .40) or circumference (P = .10) measurements of the nerves between male and female patients. A significant correlation existed between the body mass index and symptomatic (r = 0.424; P = .045) and asymptomatic (r = 0.443; P = .037) cross-sectional areas. There was no correlation shown between the cross-sectional area of the symptomatic nerve and the severity of Headache Impact Test 6 scores (r = -0.342; P = .179). We report sonographic evidence showing an increased cross-sectional area and circumference of the symptomatic greater occipital nerve in patients with unilateral occipital neuralgia.

Annular-Cross-Section CFE Chamber

NASA Technical Reports Server (NTRS)

Sharnez, Rizwan; Sammons, David W.

1994-01-01

Proposed continuous-flow-electrophoresis (CFE) chamber of annular cross section offers advantages over conventional CFE chamber, and wedge-cross-section chamber described in "Increasing Sensitivity in Continuous-Flow Electrophoresis" (MFS-26176). In comparison with wedge-shaped chamber, chamber of annular cross section virtually eliminates such wall effects as electro-osmosis and transverse gradients of velocity. Sensitivity enhanced by incorporating gradient maker and radial (collateral) flow.

Semi-empirical and empirical L X-ray production cross sections for elements with 50 ⩽ Z ⩽ 92 for protons of 0.5 3.0 MeV

NASA Astrophysics Data System (ADS)

Nekab, M.; Kahoul, A.

2006-04-01

We present in this contribution, semi-empirical production cross sections of the main X-ray lines Lα, Lβ and Lγ for elements from Sn to U and for protons with energies varying from 0.5 to 3.0 MeV. The theoretical X-ray production cross sections are firstly calculated from the theoretical ionization cross sections of the L i ( i = 1, 2, 3) subshell within the ECPSSR theory. The semi-empirical Lα, Lβ and Lγ cross sections are then deduced by fitting the available experimental data normalized to their corresponding theoretical values and give the better representation of the experimental data in some cases. On the other hand, the experimental data are directly fitted to deduce the empirical L X-ray production cross sections. A comparison is made between the semi-empirical cross sections, the empirical cross sections reported in this work and the empirical ones reported by Reis and Jesus [M.A. Reis, A.P. Jesus, Atom. Data Nucl. Data Tables 63 (1996) 1] and those of Strivay and Weber [Strivay, G. Weber, Nucl. Instr. and Meth. B 190 (2002) 112].

Measurement of electron impact collisional excitation cross sections of Ni to Ge-like gold

DOE PAGES

May, M. J.; Beiersdorfer, P.; Jordan, N.; ...

2017-03-01

We have measured the collisional excitation cross sections for the 3d→4f and 3d→5f excitations in Au ions near the Ni-like charge state by using beam plasmas created in the Livermore electron beam ion trap EBIT-I. The cross sections have been experimentally determined at approximately 1, 2 and 3 keV above the threshold energy, ET, for the 3d→4f excitations (ET ~2.5 keV) and at approximately 0.1, 1 and 2 keV above the threshold energy for the 3d→5f excitations (ET ~3.3 keV). The cross section measurements were made possible by using the GSFC x-ray microcalorimeter at the Livermore EBIT facility. The absolutemore » cross sections are determined from the ratio of the intensity of the collisionally excited bound-bound transitions to the intensity of the radiative recombination lines produced in EBIT-I plasmas. The effects of polarization and Auger decay channels are accounted for in the cross section determination. Measured cross sections are compared with those from HULLAC, DWS and FAC calculations. Finally, the measurements demonstrate that some errors exist in the calculated excitation cross sections.« less

Measurement of electron impact collisional excitation cross sections of Ni to Ge-like gold

NASA Astrophysics Data System (ADS)

May, M. J.; Beiersdorfer, P.; Jordan, N.; Scofield, J. H.; Reed, K. J.; Brown, G. V.; Hansen, S. B.; Porter, F. S.; Kelley, R.; Kilbourne, C. A.; Boyce, K. R.

2017-03-01

We have measured the collisional excitation cross sections for the 3d→4f and 3d→5f excitations in Au ions near the Ni-like charge state by using beam plasmas created in the Livermore electron beam ion trap EBIT-I. The cross sections have been experimentally determined at approximately 1, 2 and 3 keV above the threshold energy, ET, for the 3d→4f excitations (ET ˜ 2.5 keV) and at approximately 0.1, 1 and 2 keV above the threshold energy for the 3d→5f excitations (ET ˜ 3.3 keV). The cross section measurements were made possible by using the GSFC x-ray microcalorimeter at the Livermore EBIT facility. The absolute cross sections are determined from the ratio of the intensity of the collisionally excited bound-bound transitions to the intensity of the radiative recombination lines produced in EBIT-I plasmas. The effects of polarization and Auger decay channels are accounted for in the cross section determination. Measured cross sections are compared with those from HULLAC, DWS and FAC calculations. The measurements demonstrate that some errors exist in the calculated excitation cross sections.

Neutron Thermal Cross Sections, Westcott Factors, Resonance Integrals, Maxwellian Averaged Cross Sections and Astrophysical Reaction Rates Calculated from the ENDF/B-VII.1, JEFF-3.1.2, JENDL-4.0, ROSFOND-2010, CENDL-3.1 and EAF-2010 Evaluated Data Libraries

NASA Astrophysics Data System (ADS)

Pritychenko, B.; Mughabghab, S. F.

2012-12-01

We present calculations of neutron thermal cross sections, Westcott factors, resonance integrals, Maxwellian-averaged cross sections and astrophysical reaction rates for 843 ENDF materials using data from the major evaluated nuclear libraries and European activation file. Extensive analysis of newly-evaluated neutron reaction cross sections, neutron covariances, and improvements in data processing techniques motivated us to calculate nuclear industry and neutron physics quantities, produce s-process Maxwellian-averaged cross sections and astrophysical reaction rates, systematically calculate uncertainties, and provide additional insights on currently available neutron-induced reaction data. Nuclear reaction calculations are discussed and new results are presented. Due to space limitations, the present paper contains only calculated Maxwellian-averaged cross sections and their uncertainties. The complete data sets for all results are published in the Brookhaven National Laboratory report.

A method for calculating proton-nucleus elastic cross-sections

NASA Technical Reports Server (NTRS)

Tripathi, R. K.; Wilson, J. W.; Cucinotta, F. A.

2002-01-01

Recently [Nucl. Instr. and Meth. B 145 (1998) 277; Extraction of in-medium nucleon-nucleon amplitude from experiment, NASA-TP, 1998], we developed a method of extracting nucleon-nucleon (N-N) cross-sections in the medium directly from experiment. The in-medium N-N cross-sections form the basic ingredients of several heavy-ion scattering approaches including the coupled-channel approach developed at the NASA Langley Research Center. We investigated [Proton-nucleus total cross-sections in coupled-channel approach, NASA/TP, 2000; Nucl. Instr. and Meth. B 173-174 (2001) 391] the ratio of real to imaginary part of the two body scattering amplitude in the medium. These ratios are used in combination with the in-medium N-N cross-sections to calculate proton-nucleus elastic cross-sections. The agreement is excellent with the available experimental data. These cross-sections are needed for the radiation risk assessment of space missions. c2002 Elsevier Science B.V. All rights reserved.

Single step sequential polydimethylsiloxane wet etching to fabricate a microfluidic channel with various cross-sectional geometries

NASA Astrophysics Data System (ADS)

Wang, C.-K.; Liao, W.-H.; Wu, H.-M.; Lo, Y.-H.; Lin, T.-R.; Tung, Y.-C.

2017-11-01

Polydimethylsiloxane (PDMS) has become a widely used material to construct microfluidic devices for various biomedical and chemical applications due to its desirable material properties and manufacturability. PDMS microfluidic devices are usually fabricated using soft lithography replica molding methods with master molds made of photolithogrpahy patterned photoresist layers on silicon wafers. The fabricated microfluidic channels often have rectangular cross-sectional geometries with single or multiple heights. In this paper, we develop a single step sequential PDMS wet etching process that can be used to fabricate microfluidic channels with various cross-sectional geometries from single-layer PDMS microfluidic channels. The cross-sections of the fabricated channel can be non-rectangular, and varied along the flow direction. Furthermore, the fabricated cross-sectional geometries can be numerically simulated beforehand. In the experiments, we fabricate microfluidic channels with various cross-sectional geometries using the developed technique. In addition, we fabricate a microfluidic mixer with alternative mirrored cross-sectional geometries along the flow direction to demonstrate the practical usage of the developed technique.

The formation of excited atoms during charge exchange between hydrogen ions and alkali atoms. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Nieman, R. A.

1971-01-01

The charge exchange cross sections for protons and various alkali atoms are calculated using the classical approximation of Gryzinski. It is assumed that the hydrogen atoms resulting from charge exchange exist in all possible excited states. Charge transfer collisions between protons and potassium as well as protons and sodium atoms are studied. The energy range investigated is between 4 and 30 keV. The theoretical calculations of the capture cross section and the cross section for the creation of metastable 2S hydrogen are compared to experimental values. Good quantitative agreement is found for the capture cross section but only qualitative agreement for the metastable cross section. Analysis of the Lyman alpha window in molecular oxygen suggests that measured values of the metastable cross section may be in error. Thick alkali target data are also presented. This allows the determination of the total electron loss cross section. Finally, some work was done with H2(+).

Angular distributions for H- formation in single collisions of H+ on Mg

NASA Astrophysics Data System (ADS)

Alvarez, I.; Cisneros, C.; Russek, A.

1982-07-01

Absolute differential cross sections have been measured for H- formation in single collisions of H+ on Mg in the energy range from 0.5 to 5.0 keV. Total cross sections, obtained by direct integration of these differential cross sections, are in good agreement with earlier total-cross-section measurements of Morgan and Eriksen in the energy range common to the two experiments and are in good agreement with the calculated total cross sections of Olson and Liu. The differential cross sections are strongly peaked in the forward direction. The functional form and scaling properties of this forward peak strongly indicate that it is a glory maximum, which occurs when the classical deflection function changes over from attractive to repulsive at some finite impact parameter. The differential cross sections from 1.0 to 5.0 keV show no other structure, but below 1.0 keV a τ-dependent structure is observed which becomes more pronounced as the collision energy decreases. 1982 The American Physical Society.

Neutron Fission of 235,237,239U and 241,243Pu: Cross Sections, Integral Cross Sections and Cross Sections on Excited States

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

Younes, W; Britt, H C

In a recent paper submitted to Phys. Rev. C they have presented estimates for (n,f) cross sections on a series of Thorium, Uranium and Plutonium isotopes over the range E{sub n} = 0.1-2.5 MeV. The (n,f) cross sections for many of these isotopes are difficult or impossible to measure in the laboratory. The cross sections were obtained from previous (t,pf) reaction data invoking a model which takes into account the differences between (t,pf) and (n,f) reaction processes, and which includes improved estimates for the neutron compound formation process. The purpose of this note is: (1) to compare the estimated crossmore » sections to current data files in both ENDF and ENDL databases; (2) to estimate ratios of cross sections relatively to {sup 235}U integrated over the ''tamped flattop'' critical assembly spectrum that was used in the earlier {sup 237}U report; and (3) to show the effect on the integral cross sections when the neutron capturing state is an excited rotational state or an isomer. The isomer and excited state results are shown for {sup 235}U and {sup 237}U.« less

IEP: Developing Criteria for the Evaluation of Individualized Education Program Provisions. Exploring Issues in the Implementation of P.L. 94-142.

ERIC Educational Resources Information Center

LINC Resources, Inc., Columbus, OH.

Four papers address approaches to evaluate the implementation of the individualized education program (IEP) provisions of P.L. 94-142, The Education for All Handicapped Children Act. The papers are "Auditing the IEP System: A Self-Audit System for Use by Local Education Agencies" by Beth Stephens and Daniel Macy, which examines a 10-step…

DARK Technology Transition Plan

DTIC Science & Technology

1990-04-01

or suspend/resume primitives , and bounded delays. Under the above circumstances, the extra language features, and the hidden system calls they... system , this implies that the mechanisms by which units interact - to synchronise , communicate, schedule one another, or alert one another - should be...the Kernel environment are: " The host system is a DEC VAX operating under VMS 5.0 (the specific host used at the SEI is a MicroVAX II operating under

Behavior of boundary string field theory associated with integrable massless flow.

PubMed

Fujii, A; Itoyama, H

2001-06-04

We put forward an idea that the boundary entropy associated with integrable massless flow of thermodynamic Bethe ansatz (TBA) is identified with tachyon action of boundary string field theory. We show that the temperature parametrizing a massless flow in the TBA formalism can be identified with tachyon energy for the classical action at least near the ultraviolet fixed point, i.e., the open string vacuum.

Laser-Material Interactions

DTIC Science & Technology

1989-09-01

energy polarized in the TE direction is couple ,’ out of the zero-order reflected beam . Careful variations of grating depth and profile must be...the necessary decrease in the ,ero-order reflected and transmitted beams . Yamashita et al. [22] treated the coupling prob~em wli:hin the Rayleigh...OC(koh) 2, increase in the SPW intensity with grating depth for shallow gratings, saturation of the SPW intensity at a coupling efficiency near 100

Fast, Distributed Algorithms in Deep Networks

DTIC Science & Technology

2016-05-11

may not have realized how vital she was in making this project a reality is Professor Crainiceanu. Without knowing who you were, you invited me into...objective function. Training is complete when (2) converges, or stated alternatively , when the difference between t and φL can no longer be...the state-of-the art approaches simply rely on random initialization. We propose an alternative 10 (a) Features in 1-dimensional space (b) Features

Nuclear Weapons and Nuclear War. Papers Based on a Symposium of the Forum on Physics and Society of the American Physical Society, (Washington, D.C., April 1982).

ERIC Educational Resources Information Center

Morrison, Philip; And Others

Three papers on nuclear weapons and nuclear war, based on talks given by distinguished physicists during an American Physical Society-sponsored symposium, are provided in this booklet. They include "Caught Between Asymptotes" (Philip Morrison), "We are not Inferior to the Soviets" (Hans A. Bethe), and "MAD vs. NUTS"…

Hans Bethe and Physics in/of the 20th Century

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

Schweber, Silvan

2012-12-12

I will present some facets of Hans Bethe’s life to illustrate how I have used biography to narrate certain aspects of the history of twentieth century physics. I will focus on post World War II quantum field theory, on the relation between solid state/condensed matter physics and high energy physics, and make some observations regarding certain “top down” views in solid state physics in postmodernity.

Georgetown University and Hampton University Prostate Cancer Undergraduate Fellowship Program

DTIC Science & Technology

2015-10-01

Tyanna Jones-Gray (Dr. Vicente Notario), Ms. Damara Miller (Dr. Eliot Rosen), Ms. Jasmine Hatcher-Moorman (Dr. MaryBeth Martin), and Mr. Isaiah Brown...undergraduate students: 1. The Hampton University undergraduates (Ms. Tyanna Jones-Gray, Ms. Damara Miller, Ms. Jasmine Hatcher-Moorman, and Mr...cancer progression. Dr. Martin’s lab has identified the environmental hormones referred to as metallo- hormones. In Dr. Martin’s laboratory, Jasmine

Reduction of Risk for Low Back Injury in Theater of Operations

DTIC Science & Technology

2015-06-01

Assessed for eligibility (n = 698) 14 Figure 4. Predicted (from regression) isometric lumbar extension strength ( torque ) mean values (adjusted by...resistance exercise to the lumbar extensors in the ranges required for strength development, torque production from the gluteals and hamstrings must be...the small lumbar muscles play only a minor role in trunk extension torque production.17 Thus, they are considered to be the weak link in trunk

Technology, FID, and Afghanistan: A Model for Aviation Capacity

DTIC Science & Technology

2017-04-05

Force. Through case study, it analyzes how FID definitions and goals eroded under political pressure. Following this, Afghanistan is used to show...national aviation technology capacity, where these nations are weak, and which societal strengths to leverage. Case studies demonstrate how it can be...the other way around. In the case of Afghanistan, the U.S. Air Force (USAF) attempted to cultivate advanced aviation capabilities within a low

Effect of reagent rotation on the integral cross-sections and isotopic branching of the reactions H - + HD and D - + HD

NASA Astrophysics Data System (ADS)

Zhang, Wei; Liu, Yufang; He, Xiaohu

2010-04-01

A quasi-classical trajectory (QCT) method has been used to calculate integral reaction cross-section for H - + HD and D - + HD. The influence of rotation of the reagent on the integral reaction cross-section and the product branching ratios of the title reactions are discussed. The results indicate that the reactive cross-section of H(D) - + HD → HH(D) + D - decreases with an increase of the j for E tran ⩽ 1.5 eV. The results also show that the reactive cross-section of D(H) - + HD → DD(H) + H - decreases with an increase of the j for E tran ⩽ 1.0 eV and that the integral cross-sections of title reactions are sensitive to the reagent rotation.

Evaluation of cross sections for neutron-induced reactions in sodium. [10/sup -5/ eV to 20 MeV

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

Larson, D.C.

1980-09-01

An evaluation of the neutron-induced cross sections of /sup 23/Na has been done for the energy range from 10/sup -5/ eV to 20 MeV. All significant cross sections are given, including differential cross sections for production of gamma rays. The recommended values are based on experimental data where available, and use results of a consistent model code analysis of available data to predict cross sections where there are no experimental data. This report describes the evaluation that was submitted to the Cross Section Evaluation Working Group (CSEWG) for consideration as a part of the Evaluated Nuclear Data File, Version V,more » and subsequently issued as MAT 1311. 126 references, 130 figures, 14 tables.« less

Three-dimensional object surface identification

NASA Astrophysics Data System (ADS)

Celenk, Mehmet

1995-03-01

This paper describes a computationally efficient matching method for inspecting 3D objects using their serial cross sections. Object regions of interest in cross-sectional binary images of successive slices are aligned with those of the models. Cross-sectional differences between the object and the models are measured in the direction of the gradient of the cross section boundary. This is repeated in all the cross-sectional images. The model with minimum average cross-sectional difference is selected as the best match to the given object (i.e., no defect). The method is tested using various computer generated surfaces and matching results are presented. It is also demonstrated using Symult S-2010 16-node system that the method is suitable for parallel implementation in massage passing processors with the maximum attainable speedup (close to 16 for S-2010).

Polynomial coefficients for calculating O2 Schumann-Runge cross sections at 0.5/cm resolution

NASA Technical Reports Server (NTRS)

Minschwaner, K.; Anderson, G. P.; Hall, L. A.; Yoshino, K.

1992-01-01

O2 cross sections from 49,000 to 57,000/cm have been fitted with temperature dependent polynomial expressions, providing an accurate and efficient means of determining Schumann-Runge band cross sections for temperatures between 130 and 500 K. The least squares fits were carried out on a 0.5/cm spectral grid, using cross sections obtained from a Schumann-Runge line-by-line model that incorporates the most recent spectroscopic data. The O2 cross sections do not include the underlying Herzberg continuum, but they do contain contributions from the temperature dependent Schumann-Runge continuum. The cross sections are suitable for use in UV transmission calculations at high spectral resolution. They should also prove useful for updating existing parameterizations of ultraviolet transmission and O2 photolysis.

An Equivalent cross-section Framework for improving computational efficiency in Distributed Hydrologic Modelling

NASA Astrophysics Data System (ADS)

Khan, Urooj; Tuteja, Narendra; Ajami, Hoori; Sharma, Ashish

2014-05-01

While the potential uses and benefits of distributed catchment simulation models is undeniable, their practical usage is often hindered by the computational resources they demand. To reduce the computational time/effort in distributed hydrological modelling, a new approach of modelling over an equivalent cross-section is investigated where topographical and physiographic properties of first-order sub-basins are aggregated to constitute modelling elements. To formulate an equivalent cross-section, a homogenization test is conducted to assess the loss in accuracy when averaging topographic and physiographic variables, i.e. length, slope, soil depth and soil type. The homogenization test indicates that the accuracy lost in weighting the soil type is greatest, therefore it needs to be weighted in a systematic manner to formulate equivalent cross-sections. If the soil type remains the same within the sub-basin, a single equivalent cross-section is formulated for the entire sub-basin. If the soil type follows a specific pattern, i.e. different soil types near the centre of the river, middle of hillslope and ridge line, three equivalent cross-sections (left bank, right bank and head water) are required. If the soil types are complex and do not follow any specific pattern, multiple equivalent cross-sections are required based on the number of soil types. The equivalent cross-sections are formulated for a series of first order sub-basins by implementing different weighting methods of topographic and physiographic variables of landforms within the entire or part of a hillslope. The formulated equivalent cross-sections are then simulated using a 2-dimensional, Richards' equation based distributed hydrological model. The simulated fluxes are multiplied by the weighted area of each equivalent cross-section to calculate the total fluxes from the sub-basins. The simulated fluxes include horizontal flow, transpiration, soil evaporation, deep drainage and soil moisture. To assess the accuracy of equivalent cross-section approach, the sub-basins are also divided into equally spaced multiple hillslope cross-sections. These cross-sections are simulated in a fully distributed settings using the 2-dimensional, Richards' equation based distributed hydrological model. The simulated fluxes are multiplied by the contributing area of each cross-section to get total fluxes from each sub-basin referred as reference fluxes. The equivalent cross-section approach is investigated for seven first order sub-basins of the McLaughlin catchment of the Snowy River, NSW, Australia, and evaluated in Wagga-Wagga experimental catchment. Our results show that the simulated fluxes using an equivalent cross-section approach are very close to the reference fluxes whereas computational time is reduced of the order of ~4 to ~22 times in comparison to the fully distributed settings. The transpiration and soil evaporation are the dominant fluxes and constitute ~85% of actual rainfall. Overall, the accuracy achieved in dominant fluxes is higher than the other fluxes. The simulated soil moistures from equivalent cross-section approach are compared with the in-situ soil moisture observations in the Wagga-Wagga experimental catchment in NSW, and results found to be consistent. Our results illustrate that the equivalent cross-section approach reduces the computational time significantly while maintaining the same order of accuracy in predicting the hydrological fluxes. As a result, this approach provides a great potential for implementation of distributed hydrological models at regional scales.

Beth-Uhlenbeck approach for repulsive interactions between baryons in a hadron gas

NASA Astrophysics Data System (ADS)

Vovchenko, Volodymyr; Motornenko, Anton; Gorenstein, Mark I.; Stoecker, Horst

2018-03-01

The quantum mechanical Beth-Uhlenbeck (BU) approach for repulsive hard-core interactions between baryons is applied to the thermodynamics of a hadron gas. The second virial coefficient a2—the "excluded volume" parameter—calculated within the BU approach is found to be temperature dependent, and it differs dramatically from the classical excluded volume (EV) model result. At temperatures T =100 -200 MeV, the widely used classical EV model underestimates the EV parameter for nucleons at a given value of the nucleon hard-core radius by large factors of 3-4. Previous studies, which employed the hard-core radii of hadrons as an input into the classical EV model, have to be re-evaluated using the appropriately rescaled EV parameters. The BU approach is used to model the repulsive baryonic interactions in the hadron resonance gas (HRG) model. Lattice data for the second- and fourth-order net baryon susceptibilities are described fairly well when the temperature dependent BU baryonic excluded volume parameter corresponds to nucleon hard-core radii of rc=0.25 -0.3 fm. Role of the attractive baryonic interactions is also considered. It is argued that HRG model with a constant baryon-baryon EV parameter vN N≃1 fm3 provides a simple yet efficient description of baryon-baryon interaction in the crossover temperature region.

Black Hole Formation and Fallback during the Supernova Explosion of a 40 M ⊙ Star

NASA Astrophysics Data System (ADS)

Chan, Conrad; Müller, Bernhard; Heger, Alexander; Pakmor, Rüdiger; Springel, Volker

2018-01-01

Fallback in core-collapse supernovae is considered a major ingredient for explaining abundance anomalies in metal-poor stars and the natal kicks and spins of black holes (BHs). We present a first 3D simulation of BH formation and fallback in an “aborted” neutrino-driven explosion of a 40 solar mass zero-metallicity progenitor from collapse to shock breakout. We follow the phase up to BH formation using the relativistic COCONUT-FMT code. For the subsequent evolution to shock breakout we apply the moving-mesh code AREPO to core-collapse supernovae for the first time. Our simulation shows that despite early BH formation, neutrino-heated bubbles can survive for tens of seconds before being accreted, leaving them sufficient time to transfer part of their energy to sustain the shock wave as is propagates through the envelope. Although the initial net energy (∼2 Bethe) of the neutrino-heated ejecta barely equals the binding energy of the envelope, 11 {M}ȯ of hydrogen are still expelled with an energy of 0.23 Bethe. We find no significant mixing and only a modest BH kick and spin, but speculate that stronger effects could occur for slightly more energetic explosions or progenitors with less tightly bound envelopes.

The transition probability and the probability for the left-most particle's position of the q-totally asymmetric zero range process

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

Korhonen, Marko; Lee, Eunghyun

2014-01-15

We treat the N-particle zero range process whose jumping rates satisfy a certain condition. This condition is required to use the Bethe ansatz and the resulting model is the q-boson model by Sasamoto and Wadati [“Exact results for one-dimensional totally asymmetric diffusion models,” J. Phys. A 31, 6057–6071 (1998)] or the q-totally asymmetric zero range process (TAZRP) by Borodin and Corwin [“Macdonald processes,” Probab. Theory Relat. Fields (to be published)]. We find the explicit formula of the transition probability of the q-TAZRP via the Bethe ansatz. By using the transition probability we find the probability distribution of the left-most particle'smore » position at time t. To find the probability for the left-most particle's position we find a new identity corresponding to identity for the asymmetric simple exclusion process by Tracy and Widom [“Integral formulas for the asymmetric simple exclusion process,” Commun. Math. Phys. 279, 815–844 (2008)]. For the initial state that all particles occupy a single site, the probability distribution of the left-most particle's position at time t is represented by the contour integral of a determinant.« less

The stopping power and energy straggling of light ions in graphene oxide foils

NASA Astrophysics Data System (ADS)

Mikšová, R.; Macková, A.; Malinský, P.; Sofer, Z.

2017-09-01

Energy-loss and straggling experiments were performed using 2-4 MeV 1H+ and 7.4-9.0 MeV 4He2+ ions in graphene oxide foils by the transmission technique. The thickness of the graphene oxide foils was determined using a detailed image analysis of a graphene oxide cut, which was used to refine the graphene oxide density. The density was determined by the standard technique of micro-balance weighing. The stoichiometry of the graphene oxide foils before the irradiation was determined by Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA) using 2 and 2.5 MeV 4He+. The measured energy stopping powers for hydrogen and helium ions in graphene oxide were compared with the predictions obtained from the SRIM-2013 code. The energy straggling was compared with that calculated using Bohr's, Bethe-Livingston and Yang predictions. The results show that the stopping power of graphene oxide foils irradiated by both ion species decreases with increasing energies, the differences between the measured and predicted values being below 3.8%. The energy straggling determined in our experiment is higher than Bohr's and Bethe-Livingston predicted values; the predictions by Yang are in better agreement with our experiment.

Exact solution for the quench dynamics of a nested integrable system

NASA Astrophysics Data System (ADS)

Mestyán, Márton; Bertini, Bruno; Piroli, Lorenzo; Calabrese, Pasquale

2017-08-01

Integrable models provide an exact description for a wide variety of physical phenomena. For example nested integrable systems contain different species of interacting particles with a rich phenomenology in their collective behavior, which is the origin of the unconventional phenomenon of spin-charge separation. So far, however, most of the theoretical work in the study of non-equilibrium dynamics of integrable systems has focussed on models with an elementary (i.e. not nested) Bethe ansatz. In this work we explicitly investigate quantum quenches in nested integrable systems, by generalizing the application of the quench action approach. Specifically, we consider the spin-1 Lai-Sutherland model, described, in the thermodynamic limit, by the theory of two different species of Bethe-ansatz particles, each one forming an infinite number of bound states. We focus on the situation where the quench dynamics starts from a simple matrix product state for which the overlaps with the eigenstates of the Hamiltonian are known. We fully characterize the post-quench steady state and perform several consistency checks for the validity of our results. Finally, we provide predictions for the propagation of entanglement and mutual information after the quench, which can be used as signature of the quasi-particle content of the model.

Evidence of ghost suppression in gluon mass scale dynamics

NASA Astrophysics Data System (ADS)

Aguilar, A. C.; Binosi, D.; Figueiredo, C. T.; Papavassiliou, J.

2018-03-01

In this work we study the impact that the ghost sector of pure Yang-Mills theories may have on the generation of a dynamical gauge boson mass scale, which hinges on the appearance of massless poles in the fundamental vertices of the theory, and the subsequent realization of the well-known Schwinger mechanism. The process responsible for the formation of such structures is itself dynamical in nature, and is governed by a set of Bethe-Salpeter type of integral equations. While in previous studies the presence of massless poles was assumed to be exclusively associated with the background-gauge three-gluon vertex, in the present analysis we allow them to appear also in the corresponding ghost-gluon vertex. The full analysis of the resulting Bethe-Salpeter system reveals that the contribution of the poles associated with the ghost-gluon vertex are particularly suppressed, their sole discernible effect being a slight modification in the running of the gluon mass scale, for momenta larger than a few GeV. In addition, we examine the behavior of the (background-gauge) ghost-gluon vertex in the limit of vanishing ghost momentum, and derive the corresponding version of Taylor's theorem. These considerations, together with a suitable Ansatz, permit us the full reconstruction of the pole sector of the two vertices involved.

Rényi entropies after releasing the Néel state in the XXZ spin-chain

NASA Astrophysics Data System (ADS)

Alba, Vincenzo; Calabrese, Pasquale

2017-11-01

We study the Rényi entropies in the spin-1/2 anisotropic Heisenberg chain after a quantum quench starting from the Néel state. The quench action method allows us to obtain the stationary Rényi entropies for arbitrary values of the index α as generalised free energies evaluated over a calculable thermodynamic macrostate depending on α. We work out this macrostate for several values of α and of the anisotropy Δ by solving the thermodynamic Bethe ansatz equations. By varying α different regions of the Hamiltonian spectrum are accessed. The two extremes are α\\to∞ for which the thermodynamic macrostate is either the ground state or a low-lying excited state (depending on Δ) and α=0 when the macrostate is the infinite temperature state. The Rényi entropies are easily obtained from the macrostate as function of α and a few interesting limits are analytically characterised. We provide robust numerical evidence to confirm our results using exact diagonalisation and a stochastic numerical implementation of Bethe ansatz. Finally, using tDMRG we calculate the time evolution of the Rényi entanglement entropies. For large subsystems and for any α, their density turns out to be compatible with that of the thermodynamic Rényi entropies.

Hans A. Bethe Prize: Cosmic Collisions Online - Compact Binary Mergers, Gravitational Waves and Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Shapiro, Stuart

2017-01-01

Hans A. Bethe elucidated our understanding of the fundamental forces of Nature by exploring and explaining countless phenomena occurring in nuclear laboratories and in stars. With the dawn of gravitational wave astronomy we now can probe compact binary mergers - Nature's cosmic collision experiments - to deepen our understanding, especially where strong-field gravitation is involved. In addition to gravitational waves, some mergers are likely to generate observable electromagnetic and/or neutrino radiation, heralding a new era of multimessenger astronomy. Robust numerical algorithms now allow us to simulate these events in full general relativity on supercomputers. We will describe some recent magnetohydrodynamic simulations that show how binary black hole-neutron star and neutron star-neutron star mergers can launch jets, lending support to the idea that such mergers could be the engines that power short gamma-ray bursts. We will also show how the magnetorotational collapse of very massive stars to spinning black holes immersed in magnetized accretion disks can launch jets as well, reinforcing the belief that such ``collapsars'' are the progenitors of long gamma-ray bursts. Computer-generated movies highlighting some of these simulations will be shown. We gratefully acknowledge support from NSF Grants 1300903 and 1602536 and NASA Grant NNX13AH44G.

A systematic benchmark of the ab initio Bethe-Salpeter equation approach for low-lying optical excitations of small organic molecules

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

Bruneval, Fabien; Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720; Department of Physics, University of California, Berkeley, California 94720

2015-06-28

The predictive power of the ab initio Bethe-Salpeter equation (BSE) approach, rigorously based on many-body Green’s function theory but incorporating information from density functional theory, has already been demonstrated for the optical gaps and spectra of solid-state systems. Interest in photoactive hybrid organic/inorganic systems has recently increased and so has the use of the BSE for computing neutral excitations of organic molecules. However, no systematic benchmarks of the BSE for neutral electronic excitations of organic molecules exist. Here, we study the performance of the BSE for the 28 small molecules in Thiel’s widely used time-dependent density functional theory benchmark setmore » [Schreiber et al., J. Chem. Phys. 128, 134110 (2008)]. We observe that the BSE produces results that depend critically on the mean-field starting point employed in the perturbative approach. We find that this starting point dependence is mainly introduced through the quasiparticle energies obtained at the intermediate GW step and that with a judicious choice of starting mean-field, singlet excitation energies obtained from BSE are in excellent quantitative agreement with higher-level wavefunction methods. The quality of the triplet excitations is slightly less satisfactory.« less

Strategies for cutting hospital beds: the impact on patient service.

PubMed Central

Green, L V; Nguyen, V

2001-01-01

OBJECTIVE: To develop insights on the impact of size, average length of stay, variability, and organization of clinical services on the relationship between occupancy rates and delays for beds. DATA SOURCES: The primary data source was Beth Israel Deaconess Medical Center in Boston. Secondary data were obtained from the United Hospital Fund of New York reflecting data from about 150 hospitals. STUDY DESIGN: Data from Beth Israel Deaconess on discharges and length of stay were analyzed and fit into appropriate queueing models to generate tables and graphs illustrating the relationship between the variables mentioned above and the relationship between occupancy levels and delays. In addition, specific issues of current concern to hospital administrators were analyzed, including the impact of consolidation of clinical services and utilizing hospital beds uniformly across seven days a week rather than five. PRINCIPAL FINDINGS: Using target occupancy levels as the primary determinant of bed capacity is inadequate and may lead to excessive delays for beds. Also, attempts to reduce hospital beds by consolidation of different clinical services into single nursing units may be counterproductive. CONCLUSIONS: More sophisticated methodologies are needed to support decisions that involve bed capacity and organization in order to understand the impact on patient service. Images Figure 2 PMID:11409821

Bethe, Oppenheimer, Teller and the Fermi Award: Norris Bradbury Speaks

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

Meade, Roger Allen

In 1956 the Enrico Fermi Presidential Award was established to recognize scientists, engineers, and science policymakers who gave unstintingly over their careers to advance energy science and technology. The first recipient was John von Neumann. .1 Among those scientists who were thought eligible for the award were Hans Bethe, J. Robert Oppenheimer, and Edward Teller. In 1959 Norris Bradbury was asked to comment on the relative merits of each these three men, whom he knew well from their affiliation with Los Alamos. Below is a reproduction of the letter Bradbury sent to Dr. Warren C. Johnson of the AEC’s Generalmore » Advisory Committee(GAC) containing his evaluation of each man. The letter might surprise those not accustomed to Bradbury’s modus operandi of providing very detailed and forthright answers to the AEC. The letter, itself, was found in cache of old microfilm. Whether because of the age of the microfilm or the quality of the filming process, portions of the letter are not legible. Where empty brackets appear, the word or words could not be read or deduced. Words appearing in brackets are guesses that appear, from the image, to be what was written. These guesses, of course, are just that – guesses.« less

Calculation of water equivalent thickness of materials of arbitrary density, elemental composition and thickness in proton beam irradiation

NASA Astrophysics Data System (ADS)

Zhang, Rui; Newhauser, Wayne D.

2009-03-01

In proton therapy, the radiological thickness of a material is commonly expressed in terms of water equivalent thickness (WET) or water equivalent ratio (WER). However, the WET calculations required either iterative numerical methods or approximate methods of unknown accuracy. The objective of this study was to develop a simple deterministic formula to calculate WET values with an accuracy of 1 mm for materials commonly used in proton radiation therapy. Several alternative formulas were derived in which the energy loss was calculated based on the Bragg-Kleeman rule (BK), the Bethe-Bloch equation (BB) or an empirical version of the Bethe-Bloch equation (EBB). Alternative approaches were developed for targets that were 'radiologically thin' or 'thick'. The accuracy of these methods was assessed by comparison to values from an iterative numerical method that utilized evaluated stopping power tables. In addition, we also tested the approximate formula given in the International Atomic Energy Agency's dosimetry code of practice (Technical Report Series No 398, 2000, IAEA, Vienna) and stopping power ratio approximation. The results of these comparisons revealed that most methods were accurate for cases involving thin or low-Z targets. However, only the thick-target formulas provided accurate WET values for targets that were radiologically thick and contained high-Z material.

Assessment of experimental d-PIGE γ-ray production cross sections for 12C, 14N and 16O and comparison with absolute thick target yields

NASA Astrophysics Data System (ADS)

Csedreki, L.; Halász, Z.; Kiss, Á. Z.

2016-08-01

Measured differential cross sections for deuteron induced γ-ray emission from the reactions 12C(d,pγ)13C, (Eγ = 3089 keV), 14N(d,pγ)15N (Eγ = 8310 keV) and 16O(d,pγ)17O (Eγ = 871 keV) available in the literature were assessed. In order to cross check the assessed γ-ray production cross section data, thick target γ-yields calculated from the differential cross sections were compared with available measured thick target yields. Recommended differential cross section data for each reaction were deduced for particle induced γ-ray emission (PIGE) applications.

Electron-impact excitation cross sections for the b /sup 3/. sigma. /sub u//sup +/ state of H/sub 2/

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

Khakoo, M.A.; Trajmar, S.; McAdams, R.

1987-04-01

Differential and integral cross sections for electron-impact excitation of the b /sup 3/..sigma../sub u//sup +/ state of H/sub 2/ have been determined in the 20--100-eV impact energy region. The calibration of the cross sections was achieved through the H/sub 2/ elastic scattering cross sections, which in turn were normalized to absolute He elastic scattering cross sections. Comparison is made with available experimental data and with theoretical results applying Born-Ochkur-Rudge, distorted-wave, and close-coupling approximations.

New Tools to Prepare ACE Cross-section Files for MCNP Analytic Test Problems

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

Brown, Forrest B.

Monte Carlo calculations using one-group cross sections, multigroup cross sections, or simple continuous energy cross sections are often used to: (1) verify production codes against known analytical solutions, (2) verify new methods and algorithms that do not involve detailed collision physics, (3) compare Monte Carlo calculation methods with deterministic methods, and (4) teach fundamentals to students. In this work we describe 2 new tools for preparing the ACE cross-section files to be used by MCNP ® for these analytic test problems, simple_ace.pl and simple_ace_mg.pl.

Measurement of Charged and Neutral Current e-p Deep Inelastic Scattering Cross Sections at High Q2

NASA Astrophysics Data System (ADS)

Derrick, M.; Krakauer, D.; Magill, S.; Mikunas, D.; Musgrave, B.; Repond, J.; Stanek, R.; Talaga, R. L.; Zhang, H.; Ayad, R.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Bruni, P.; Cara Romeo, G.; Castellini, G.; Chiarini, M.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; Gialas, I.; Giusti, P.; Iacobucci, G.; Laurenti, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Nemoz, C.; Palmonari, F.; Polini, A.; Sartorelli, G.; Timellini, R.; Zamora Garcia, Y.; Zichichi, A.; Bargende, A.; Crittenden, J.; Desch, K.; Diekmann, B.; Doeker, T.; Eckert, M.; Feld, L.; Frey, A.; Geerts, M.; Geitz, G.; Grothe, M.; Haas, T.; Hartmann, H.; Haun, D.; Heinloth, K.; Hilger, E.; Jakob, H.-P.; Katz, U. F.; Mari, S. M.; Mass, A.; Mengel, S.; Mollen, J.; Paul, E.; Rembser, Ch.; Schattevoy, R.; Schramm, D.; Stamm, J.; Wedemeyer, R.; Campbell-Robson, S.; Cassidy, A.; Dyce, N.; Foster, B.; George, S.; Gilmore, R.; Heath, G. P.; Heath, H. F.; Llewellyn, T. J.; Morgado, C. J.; Norman, D. J.; O'Mara, J. A.; Tapper, R. J.; Wilson, S. S.; Yoshida, R.; Rau, R. R.; Arneodo, M.; Iannotti, L.; Schioppa, M.; Susinno, G.; Bernstein, A.; Caldwell, A.; Cartiglia, N.; Parsons, J. A.; Ritz, S.; Sciulli, F.; Straub, P. B.; Wai, L.; Yang, S.; Zhu, Q.; Borzemski, P.; Chwastowski, J.; Eskreys, A.; Piotrzkowski, K.; Zachara, M.; Zawiejski, L.; Adamczyk, L.; Bednarek, B.; Jeleń, K.; Kisielewska, D.; Kowalski, T.; Rulikowska-Zarȩbska, E.; Suszycki, L.; ZajaÇ, J.; Kotański, A.; Przybycień, M.; Bauerdick, L. A.; Behrens, U.; Beier, H.; Bienlein, J. K.; Coldewey, C.; Deppe, O.; Desler, K.; Drews, G.; Flasiński, M.; Gilkinson, D. J.; Glasman, C.; Göttlicher, P.; Grosse-Knetter, J.; Gutjahr, B.; Hain, W.; Hasell, D.; Hessling, H.; Hultschig, H.; Iga, Y.; Joos, P.; Kasemann, M.; Klanner, R.; Koch, W.; Köpke, L.; Kötz, U.; Kowalski, H.; Labs, J.; Ladage, A.; Löhr, B.; Löwe, M.; Lüke, D.; Mańczak, O.; Ng, J. S.; Nickel, S.; Notz, D.; Ohrenberg, K.; Roco, M.; Rohde, M.; Roldán, J.; Schneekloth, U.; Schulz, W.; Selonke, F.; Stiliaris, E.; Surrow, B.; Voss, T.; Westphal, D.; Wolf, G.; Youngman, C.; Zhou, J. F.; Grabosch, H. J.; Kharchilava, A.; Leich, A.; Mattingly, M.; Meyer, A.; Schlenstedt, S.; Wulff, N.; Barbagli, G.; Pelfer, P.; Anzivino, G.; Maccarrone, G.; de Pasquale, S.; Votano, L.; Bamberger, A.; Eisenhardt, S.; Freidhof, A.; Söldner-Rembold, S.; Schroeder, J.; Trefzger, T.; Brook, N. H.; Bussey, P. J.; Doyle, A. T.; Fleck, J. I.; Saxon, D. H.; Utley, M. L.; Wilson, A. S.; Dannemann, A.; Holm, U.; Horstmann, D.; Neumann, T.; Sinkus, R.; Wick, K.; Badura, E.; Burow, B. D.; Hagge, L.; Lohrmann, E.; Mainusch, J.; Milewski, J.; Nakahata, M.; Pavel, N.; Poelz, G.; Schott, W.; Zetsche, F.; Bacon, T. C.; Butterworth, I.; Gallo, E.; Harris, V. L.; Hung, B. Y.; Long, K. R.; Miller, D. B.; Morawitz, P. P.; Prinias, A.; Sedgbeer, J. K.; Whitfield, A. F.; Mallik, U.; McCliment, E.; Wang, M. Z.; Wang, S. M.; Wu, J. T.; Zhang, Y.; Cloth, P.; Filges, D.; An, S. H.; Hong, S. M.; Nam, S. W.; Park, S. K.; Suh, M. H.; Yon, S. H.; Imlay, R.; Kartik, S.; Kim, H.-J.; McNeil, R. R.; Metcalf, W.; Nadendla, V. K.; Barreiro, F.; Cases, G.; Graciani, R.; Hernández, J. M.; Hervás, L.; Labarga, L.; del Peso, J.; Puga, J.; Terron, J.; de Trocóniz, J. F.; Smith, G. R.; Corriveau, F.; Hanna, D. S.; Hartmann, J.; Hung, L. W.; Lim, J. N.; Matthews, C. G.; Patel, P. M.; Sinclair, L. E.; Stairs, D. G.; St. Laurent, M.; Ullmann, R.; Zacek, G.; Bashkirov, V.; Dolgoshein, B. A.; Stifutkin, A.; Bashindzhagyan, G. L.; Ermolov, P. F.; Gladilin, L. K.; Golubkov, Y. A.; Kobrin, V. D.; Kuzmin, V. A.; Proskuryakov, A. S.; Savin, A. A.; Shcheglova, L. M.; Solomin, A. N.; Zotov, N. P.; Botje, M.; Chlebana, F.; Dake, A.; Engelen, J.; de Kamps, M.; Kooijman, P.; Kruse, A.; Tiecke, H.; Verkerke, W.; Vreeswijk, M.; Wiggers, L.; de Wolf, E.; van Woudenberg, R.; Acosta, D.; Bylsma, B.; Durkin, L. S.; Honscheid, K.; Li, C.; Ling, T. Y.; McLean, K. W.; Murray, W. N.; Park, I. H.; Romanowski, T. A.; Seidlein, R.; Bailey, D. S.; Blair, G. A.; Byrne, A.; Cashmore, R. J.; Cooper-Sarkar, A. M.; Daniels, D.; Devenish, R. C.; Harnew, N.; Lancaster, M.; Luffman, P. E.; Lindemann, L.; McFall, J. D.; Nath, C.; Noyes, V. A.; Quadt, A.; Uijterwaal, H.; Walczak, R.; Wilson, F. F.; Yip, T.; Abbiendi, G.; Bertolin, A.; Brugnera, R.; Carlin, R.; dal Corso, F.; de Giorgi, M.; Dosselli, U.; Limentani, S.; Morandin, M.; Posocco, M.; Stanco, L.; Stroili, R.; Voci, C.; Bulmahn, J.; Butterworth, J. M.; Feild, R. G.; Oh, B. Y.; Whitmore, J. J.; D'Agostini, G.; Marini, G.; Nigro, A.; Tassi, E.; Hart, J. C.; McCubbin, N. A.; Prytz, K.; Shah, T. P.; Short, T. L.; Barberis, E.; Dubbs, T.; Heusch, C.; van Hook, M.; Hubbard, B.; Lockman, W.; Rahn, J. T.; Sadrozinski, H. F.-W.; Seiden, A.; Biltzinger, J.; Schwarzer, O.; Seifert, R. J.; Walenta, A. H.; Zech, G.; Abramowicz, H.; Briskin, G.; Dagan, S.; Levy, A.; Hasegawa, T.; Hazumi, M.; Ishii, T.; Kuze, M.; Mine, S.; Nagasawa, Y.; Nakao, M.; Suzuki, I.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Chiba, M.; Hamatsu, R.; Hirose, T.; Homma, K.; Kitamura, S.; Nakamitsu, Y.; Yamauchi, K.; Cirio, R.; Costa, M.; Ferrero, M. I.; Lamberti, L.; Maselli, S.; Peroni, C.; Sacchi, R.; Solano, A.; Staiano, A.; Dardo, M.; Bailey, D. C.; Bandyopadhyay, D.; Benard, F.; Brkic, M.; Crombie, M. B.; Gingrich, D. M.; Hartner, G. F.; Joo, K. K.; Levman, G. M.; Martin, J. F.; Orr, R. S.; Sampson, C. R.; Teuscher, R. J.; Catterall, C. D.; Jones, T. W.; Kaziewicz, P. B.; Lane, J. B.; Saunders, R. L.; Shulman, J.; Blankenship, K.; Kochocki, J.; Lu, B.; Mo, L. W.; Bogusz, W.; Charchuła, K.; Ciborowski, J.; Gajewski, J.; Grzelak, G.; Kasprzak, M.; Krzyżanowski, M.; Muchorowski, K.; Nowak, R. J.; Pawlak, J. M.; Tymieniecka, T.; Wróblewski, A. K.; Zakrzewski, J. A.; Żarnecki, A. F.; Adamus, M.; Eisenberg, Y.; Karshon, U.; Revel, D.; Zer-Zion, D.; Ali, I.; Badgett, W. F.; Behrens, B.; Dasu, S.; Fordham, C.; Foudas, C.; Goussiou, A.; Loveless, R. J.; Reeder, D. D.; Silverstein, S.; Smith, W. H.; Vaiciulis, A.; Wodarczyk, M.; Tsurugai, T.; Bhadra, S.; Cardy, M. L.; Fagerstroem, C.-P.; Frisken, W. R.; Furutani, K. M.; Khakzad, M.; Schmidke, W. B.

1995-08-01

Deep inelastic e-p scattering has been studied in both the charged current (CC) and neutral current (NC) reactions at momentum transfers squared Q2 above 400 GeV2 using the ZEUS detector at the HERA ep collider. The CC and NC total cross sections, the NC to CC cross section ratio, and the differential cross sections dσ/dQ2 are presented. From the Q2 dependence of the CC cross section, the mass term in the CC propagator is determined to be MW = 76+/-16+/-13 GeV.

Effects of silicon cross section and neutron spectrum on the radial uniformity in neutron transmutation doping.

PubMed

Kim, Haksung; Ho Pyeon, Cheol; Lim, Jae-Yong; Misawa, Tsuyoshi

2012-01-01

The effects of silicon cross section and neutron spectrum on the radial uniformity of a Si-ingot are examined experimentally with various neutron spectrum conditions. For the cross section effect, the numerical results using silicon single crystal cross section reveal good agreements with experiments within relative difference of 6%, whereas the discrepancy is approximately 20% in free-gas cross section. For the neutron spectrum effect, the radial uniformity in hard neutron spectrum is found to be more flattening than that in soft spectrum. Copyright © 2011 Elsevier Ltd. All rights reserved.

Total reaction cross sections and neutron-removal cross sections of neutron-rich light nuclei measured by the COMBAS fragment-separator

NASA Astrophysics Data System (ADS)

Hue, B. M.; Isataev, T.; Erdemchimeg, B.; Artukh, A. G.; Aznabaev, D.; Davaa, S.; Klygin, S. A.; Kononenko, G. A.; Khuukhenkhuu, G.; Kuterbekov, K.; Lukyanov, S. M.; Mikhailova, T. I.; Maslov, V. A.; Mendibaev, K.; Sereda, Yu M.; Penionzhkevich, Yu E.; Vorontsov, A. N.

2017-12-01

Preliminary results of measurements of the total reaction cross sections σR and neutron removal cross section σ-xn for weakly bound 6He, 8Li, 9Be and 10Be nuclei at energy range (20-35) A MeV with 28Si target is presented. The secondary beams of light nuclei were produced by bombardment of the 22Ne (35 A MeV) primary beam on Be target and separated by COMBAS fragment-separator. In dispersive focal plane a horizontal slit defined the momentum acceptance as 1% and a wedge degrader of 200 μm Al was installed. The Bρ of the second section of the fragment-separator was adjusted for measurements in energy range (20-35) A MeV. Two-neutron removal cross sections for 6He and 10Be and one -neutron removal cross sections 8Li and 9Be were measured.

Bodies with noncircular cross sections and bank-to-turn missiles

NASA Technical Reports Server (NTRS)

Jackson, C. M., Jr.; Sawyer, W. C.

1986-01-01

An evaluation is made of prospective missile applications for noncircular cross section bodies, and of recent developments in bank-to-turn missile configuration aerodynamics. The discussion encompasses cross-flow analysis techniques, as well as study results obtained for bodies with elliptical and square cross sections and with variable cross sections. Attention is given to both the performance advantages and the stability and control problems of bank-to-turn missile configurations; the aerodynamic data presented for monoplanar configurations extend to those incorporating airbreathing propulsion systems.

Cross sections for the dissociative attachment of electrons to NO

NASA Technical Reports Server (NTRS)

Krishnakumar, E.; Srivastava, S. K.

1988-01-01

Cross sections for the production of O(-) by electron attachment to NO are reported. It is found that the maximum value of the cross section is about 52 percent higher than the measurement of Rapp and Briglia (1965). Cross sections for the process of polar dissociation, e + NO yields N(+) + O(_), have also been measured, and the threshold energy for this process has been obtained.

Ground beetle communities in a mountain river subjected to restoration: The Raba River, Polish Carpathians.

PubMed

Bednarska, Agnieszka J; Wyżga, Bartłomiej; Mikuś, Paweł; Kędzior, Renata

2018-01-01

Effects of passive restoration of mountain rivers on the organisms inhabiting exposed riverine sediments are considerably less understood than those concerning aquatic biota. Thus, the effects of a recovery of the Raba River after abandonment of maintenance of its channelization scheme on ground beetle (Coleoptera: Carabidae) communities were investigated by comparing 6 unmanaged cross-sections and 6 cross-sections from adjacent channelized reaches. In each cross-section, ground beetles were collected from 12 sampling sites in spring, summer, and autumn, and 8 habitat parameters characterizing the cross-sections and sampling sites were determined. Within a few years after abandonment of the Raba River channelization scheme, the width of this gravel-bed river increased up to three times and its multi-thread pattern became re-established. Consequently, unmanaged river cross-sections had significantly larger channel width and more low-flow channels and eroding cutbanks than channelized cross-sections. Moreover, sampling sites in the unmanaged cross-sections were typified by significantly steeper average surface slope and larger average distance from low-flow channels than the sites in channelized cross-sections. In total, 3992 individuals from 78 taxa were collected during the study. The ground beetle assemblages were significantly more abundant and richer in species in the unmanaged than in the channelized cross-sections but no significant differences in carabid diversity indices between the two cross-section types were recorded. Redundancy Analysis indicated active river zone width as the only variable explaining differences in abundance and species richness among the cross-sections. Multiple regression analysis indicated species diversity to predominantly depend on the degree of plant cover and substrate grain size. The study showed that increased availability of exposed sediments in the widened river reaches allowed ground beetles to increase their abundance and species richness within a few years after the onset of river restoration, but more time may be needed for development of more diverse carabid communities. Copyright © 2017 Elsevier B.V. All rights reserved.

Method Development for Binding Media Analysis in Painting Cross-Sections by Desorption Electrospray Ionization-Mass Spectrometry (DESI-MS).

PubMed

Watts, Kristen; Lagalante, Anthony

2018-06-06

Art conservation science is in need of a relatively nondestructive way of rapidly identifying the binding media within a painting cross-section and isolating binding media to specific layers within the cross-section. Knowledge of the stratigraphy of cross-sections can be helpful for removing possible unoriginal paint layers on the artistic work. Desorption electrospray ionization-mass spectrometry (DESI-MS) was used in ambient mode to study cross-sections from mock-up layered paint samples and samples from a 17th century baroque painting. The DESI spray was raster scanned perpendicular to the cross-section layers to maximize lateral resolution then analyzed with a triple quadrupole mass analyzer in linear ion trap mode. From these scans, isobaric mass maps were created to map the locations of masses indicative of particular binding media onto the cross-sections. Line paint-outs of pigments in different binding media showed specific and unique ions to distinguish between the modern acrylic media and the lipid containing binding media. This included: OP (EO) 9 surfactant in positive ESI for acrylic (m/z 621), and oleic (m/z 281), stearic (m/z 283), and azelaic (m/z 187) acids in negative ESI for oil and egg tempera. DESI-MS maps of mock-up cross-sections of layered pigmented binding media showed correlation between these ions and the layers with a spatial resolution of 100 μm. DESI-MS is effective in monitoring binding media within an intact painting cross-section via mass spectrometric methods. This includes distinguishing between lipid-containing and modern binding materials present in a known mockup cross section matrix as well as identifying lipid binding media in a 17th century baroque era painting. This article is protected by copyright. All rights reserved.

Production cross sections of cosmic antiprotons in the light of new data from the NA61 and LHCb experiments

NASA Astrophysics Data System (ADS)

Korsmeier, Michael; Donato, Fiorenza; Di Mauro, Mattia

2018-05-01

The cosmic-ray flux of antiprotons is measured with high precision by the space-borne particle spectrometers AMS-02. Its interpretation requires a correct description of the dominant production process for antiprotons in our Galaxy, namely, the interaction of cosmic-ray proton and helium with the interstellar medium. In light of new cross section measurements by the NA61 experiment of p +p →p ¯+X and the first ever measurement of p +He →p ¯+X by the LHCb experiment, we update the parametrization of proton-proton and proton-nucleon cross sections. We find that the LHCb p He data constrain a shape for the cross section at high energies and show for the first time how well the rescaling from the p p channel applies to a helium target. By using p p , p He and p C data we estimate the uncertainty on the Lorentz invariant cross section for p +He →p ¯+X . We use these new cross sections to compute the source term for all the production channels, considering also nuclei heavier than He both in cosmic rays and the interstellar medium. The uncertainties on the total source term are up to ±20 % and slightly increase below antiproton energies of 5 GeV. This uncertainty is dominated by the p +p →p ¯+X cross section, which translates into all channels since we derive them using the p p cross sections. The cross sections to calculate the source spectra from all relevant cosmic-ray isotopes are provided in Supplemental Material. We finally quantify the necessity of new data on antiproton production cross sections, and pin down the kinematic parameter space which should be covered by future data.

Automatic arteriovenous crossing phenomenon detection on retinal fundus images

NASA Astrophysics Data System (ADS)

Hatanaka, Yuji; Muramatsu, Chisako; Hara, Takeshi; Fujita, Hiroshi

2011-03-01

Arteriolosclerosis is one cause of acquired blindness. Retinal fundus image examination is useful for early detection of arteriolosclerosis. In order to diagnose the presence of arteriolosclerosis, the physicians find the silver-wire arteries, the copper-wire arteries and arteriovenous crossing phenomenon on retinal fundus images. The focus of this study was to develop the automated detection method of the arteriovenous crossing phenomenon on the retinal images. The blood vessel regions were detected by using a double ring filter, and the crossing sections of artery and vein were detected by using a ring filter. The center of that ring was an interest point, and that point was determined as a crossing section when there were over four blood vessel segments on that ring. And two blood vessels gone through on the ring were classified into artery and vein by using the pixel values on red and blue component image. Finally, V2-to-V1 ratio was measured for recognition of abnormalities. V1 was the venous diameter far from the blood vessel crossing section, and V2 was the venous diameter near from the blood vessel crossing section. The crossing section with V2-to-V1 ratio over 0.8 was experimentally determined as abnormality. Twenty four images, including 27 abnormalities and 54 normal crossing sections, were used for preliminary evaluation of the proposed method. The proposed method was detected 73% of crossing sections when the 2.8 sections per image were mis-detected. And, 59% of abnormalities were detected by measurement of V1-to-V2 ratio when the 1.7 sections per image were mis-detected.

Electron impact excitation of H2 - Rydberg band systems and the benchmark dissociative cross section for H Lyman-alpha

NASA Technical Reports Server (NTRS)

Shemansky, D. E.; Hall, D. T.; Ajello, J. M.

1985-01-01

The cross sections sigma R 1 (2p) for excitation of H Ly-alpha emission produced by electron impact on H2 is reexamined. A more accurate estimate for sigma R 1 (2p) is obtained based on Born approximation estimates of the H2 Rydberg system cross sections using measured relative excitation functions. The obtained value is (8.18 + or -1.2) x 10 to the -18th sq cm at 100 eV, a factor of 0.69 below the value universally applied to cross section measurements over the past decade. Cross sections for the H2 Rydberg systems fixed in magnitude by the Born approximation have also been obtained using experimentally determined excitation functions. Accurate analytic expressions for these cross sections allow the direct calculation of rate coefficients.

Creation of problem-dependent Doppler-broadened cross sections in the KENO Monte Carlo code

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

Hart, Shane W. D.; Celik, Cihangir; Maldonado, G. Ivan

2015-11-06

In this paper, we introduce a quick method for improving the accuracy of Monte Carlo simulations by generating one- and two-dimensional cross sections at a user-defined temperature before performing transport calculations. A finite difference method is used to Doppler-broaden cross sections to the desired temperature, and unit-base interpolation is done to generate the probability distributions for double differential two-dimensional thermal moderator cross sections at any arbitrarily user-defined temperature. The accuracy of these methods is tested using a variety of contrived problems. In addition, various benchmarks at elevated temperatures are modeled, and results are compared with benchmark results. Lastly, the problem-dependentmore » cross sections are observed to produce eigenvalue estimates that are closer to the benchmark results than those without the problem-dependent cross sections.« less

Measurement of neutrino-induced charged-current charged pion production cross sections on mineral oil at Eν˜1GeV

NASA Astrophysics Data System (ADS)

Aguilar-Arevalo, A. A.; Anderson, C. E.; Bazarko, A. O.; Brice, S. J.; Brown, B. C.; Bugel, L.; Cao, J.; Coney, L.; Conrad, J. M.; Cox, D. C.; Curioni, A.; Dharmapalan, R.; Djurcic, Z.; Finley, D. A.; Fleming, B. T.; Ford, R.; Garcia, F. G.; Garvey, G. T.; Grange, J.; Green, C.; Green, J. A.; Hart, T. L.; Hawker, E.; Imlay, R.; Johnson, R. A.; Karagiorgi, G.; Kasper, P.; Katori, T.; Kobilarcik, T.; Kourbanis, I.; Koutsoliotas, S.; Laird, E. M.; Linden, S. K.; Link, J. M.; Liu, Y.; Liu, Y.; Louis, W. C.; Mahn, K. B. M.; Marsh, W.; Mauger, C.; McGary, V. T.; McGregor, G.; Metcalf, W.; Meyers, P. D.; Mills, F.; Mills, G. B.; Monroe, J.; Moore, C. D.; Mousseau, J.; Nelson, R. H.; Nienaber, P.; Nowak, J. A.; Osmanov, B.; Ouedraogo, S.; Patterson, R. B.; Pavlovic, Z.; Perevalov, D.; Polly, C. C.; Prebys, E.; Raaf, J. L.; Ray, H.; Roe, B. P.; Russell, A. D.; Sandberg, V.; Schirato, R.; Schmitz, D.; Shaevitz, M. H.; Shoemaker, F. C.; Smith, D.; Soderberg, M.; Sorel, M.; Spentzouris, P.; Spitz, J.; Stancu, I.; Stefanski, R. J.; Sung, M.; Tanaka, H. A.; Tayloe, R.; Tzanov, M.; van de Water, R.; Wascko, M. O.; White, D. H.; Wilking, M. J.; Yang, H. J.; Zeller, G. P.; Zimmerman, E. D.

2011-03-01

Using a high-statistics, high-purity sample of νμ-induced charged current, charged pion events in mineral oil (CH2), MiniBooNE reports a collection of interaction cross sections for this process. This includes measurements of the CCπ+ cross section as a function of neutrino energy, as well as flux-averaged single- and double-differential cross sections of the energy and direction of both the final-state muon and pion. In addition, each of the single-differential cross sections are extracted as a function of neutrino energy to decouple the shape of the MiniBooNE energy spectrum from the results. In many cases, these cross sections are the first time such quantities have been measured on a nuclear target and in the 1 GeV energy range.

Communication: Electron ionization of DNA bases.

PubMed

Rahman, M A; Krishnakumar, E

2016-04-28

No reliable experimental data exist for the partial and total electron ionization cross sections for DNA bases, which are very crucial for modeling radiation damage in genetic material of living cell. We have measured a complete set of absolute partial electron ionization cross sections up to 500 eV for DNA bases for the first time by using the relative flow technique. These partial cross sections are summed to obtain total ion cross sections for all the four bases and are compared with the existing theoretical calculations and the only set of measured absolute cross sections. Our measurements clearly resolve the existing discrepancy between the theoretical and experimental results, thereby providing for the first time reliable numbers for partial and total ion cross sections for these molecules. The results on fragmentation analysis of adenine supports the theory of its formation in space.

Photon scattering cross sections of H2 and He measured with synchrotron radiation

NASA Technical Reports Server (NTRS)

Ice, G. E.

1977-01-01

Total (elastic + inelastic) differential photon scattering cross sections have been measured for H2 gas and He, using an X-ray beam. Absolute measured cross sections agree with theory within the probable errors. Relative cross sections (normalized to theory at large S) agree to better than one percent with theoretical values calculated from wave functions that include the effect of electron-electron Coulomb correlation, but the data deviate significantly from theoretical independent-particle (e.g., Hartree-Fock) results. The ratios of measured absolute He cross sections to those of H2, at any given S, also agree to better than one percent with theoretical He-to-H2 cross-section ratios computed from correlated wave functions. It appears that photon scattering constitutes a very promising tool for probing electron correlation in light atoms and molecules.

Electron impact ionisation cross section for organoplatinum compounds

NASA Astrophysics Data System (ADS)

Mahato, Dibyendu; Naghma, Rahla; Alam, Mohammad Jane; Ahmad, Shabbir; Antony, Bobby

2016-11-01

This article reports electron impact ionisation cross sections for platinum-based drugs viz., cisplatin (H6N2Cl2Pt), carboplatin (C6H12N2O4Pt), oxaliplatin (C8H14N2O4Pt), nedaplatin (C2H8N2O3Pt) and satraplatin (C10H22ClN2O4Pt) complexes used in the cancer chemotherapy. The multi-scattering centre spherical complex optical potential formalism is used to obtain the inelastic cross section for these large molecules upon electron impact. The ionisation cross section is derived from the inelastic cross section employing complex scattering potential-ionisation contribution method. Comparison is made with previous results, where ever available and overall a reasonable agreement is observed. This is the first attempt to report total ionisation cross sections for nedaplatin and satraplatin complexes.

Effect of wave function on the proton induced L XRP cross sections for 62Sm and 74W

NASA Astrophysics Data System (ADS)

Shehla, Kaur, Rajnish; Kumar, Anil; Puri, Sanjiv

2015-08-01

The Lk(k= 1, α, β, γ) X-ray production cross sections have been calculated for 74W and 62Sm at different incident proton energies ranging 1-5 MeV using theoretical data sets of different physical parameters, namely, the Li(i=1-3) sub-shell X-ray emission rates based on the Dirac-Fork (DF) model, the fluorescence and Coster Kronig yields based on the Dirac- Hartree-Slater (DHS) model and two sets the proton ionization cross sections based on the DHS model and the ECPSSR in order to assess the influence of the wave function on the XRP cross sections. The calculated cross sections have been compared with the measured cross sections reported in the recent compilation to check the reliability of the calculated values.

Comparative analysis of characteristic electron energy loss spectra and inelastic scattering cross-section spectra of Fe

NASA Astrophysics Data System (ADS)

Parshin, A. S.; Igumenov, A. Yu.; Mikhlin, Yu. L.; Pchelyakov, O. P.; Zhigalov, V. S.

2016-05-01

The inelastic electron scattering cross section spectra of Fe have been calculated based on experimental spectra of characteristic reflection electron energy loss as dependences of the product of the inelastic mean free path by the differential inelastic electron scattering cross section on the electron energy loss. It has been shown that the inelastic electron scattering cross-section spectra have certain advantages over the electron energy loss spectra in the analysis of the interaction of electrons with substance. The peaks of energy loss in the spectra of characteristic electron energy loss and inelastic electron scattering cross sections have been determined from the integral and differential spectra. It has been shown that the energy of the bulk plasmon is practically independent of the energy of primary electrons in the characteristic electron energy loss spectra and monotonically increases with increasing energy of primary electrons in the inelastic electron scattering cross-section spectra. The variation in the maximum energy of the inelastic electron scattering cross-section spectra is caused by the redistribution of intensities over the peaks of losses due to various excitations. The inelastic electron scattering cross-section spectra have been analyzed using the decomposition of the spectra into peaks of the energy loss. This method has been used for the quantitative estimation of the contributions from different energy loss processes to the inelastic electron scattering cross-section spectra of Fe and for the determination of the nature of the energy loss peaks.

Peeling Off Neutron Skins from Neutron-Rich Nuclei: Constraints on the Symmetry Energy from Neutron-Removal Cross Sections

NASA Astrophysics Data System (ADS)

Aumann, T.; Bertulani, C. A.; Schindler, F.; Typel, S.

2017-12-01

An experimentally constrained equation of state of neutron-rich matter is fundamental for the physics of nuclei and the astrophysics of neutron stars, mergers, core-collapse supernova explosions, and the synthesis of heavy elements. To this end, we investigate the potential of constraining the density dependence of the symmetry energy close to saturation density through measurements of neutron-removal cross sections in high-energy nuclear collisions of 0.4 to 1 GeV /nucleon . We show that the sensitivity of the total neutron-removal cross section is high enough so that the required accuracy can be reached experimentally with the recent developments of new detection techniques. We quantify two crucial points to minimize the model dependence of the approach and to reach the required accuracy: the contribution to the cross section from inelastic scattering has to be measured separately in order to allow a direct comparison of experimental cross sections to theoretical cross sections based on density functional theory and eikonal theory. The accuracy of the reaction model should be investigated and quantified by the energy and target dependence of various nucleon-removal cross sections. Our calculations explore the dependence of neutron-removal cross sections on the neutron skin of medium-heavy neutron-rich nuclei, and we demonstrate that the slope parameter L of the symmetry energy could be constrained down to ±10 MeV by such a measurement, with a 2% accuracy of the measured and calculated cross sections.

Semi-empirical scaling for ion–atom single charge exchange cross sections in the intermediate velocity regime

DOE PAGES

Friedman, B.; DuCharme, G.

2017-05-11

We present a semi-empirical scaling law for non-resonant ion–atom single charge exchange cross sections for collisions with velocities frommore » $${10}^{7}\\,{\\rm{t}}{\\rm{o}}\\,{10}^{9}\\,\\mathrm{cm}\\,{{\\rm{s}}}^{-1}$$ and ions with positive charge $$q\\lt 8$$. Non-resonant cross sections tend to have a velocity peak at collision velocities $$v\\lesssim 1\\ {\\rm{a}}{\\rm{u}}$$ with exponential decay around this peak. We construct a scaling formula for the location of this peak then choose a functional form for the cross section curve and scale it. The velocity at which the cross section peaks, v m, is proportional to the energy defect of the collision, $${\\rm{\\Delta }}E$$, which we predict with the decay approximation. The value of the cross section maximum is proportional to the charge state q, inversely proportional to the target ionization energy I T, and inversely proportional to v m. For the shape of the cross section curve, we use a function that decays exponentially asymptotically at high and low velocities. We scale this function with parameters $${v}_{{\\rm{m}}},{I}_{{\\rm{T}}},{Z}_{{\\rm{T}}},\\mathrm{and}\\ {Z}_{{\\rm{P}}}$$, where the $${Z}_{{\\rm{T}},{\\rm{P}}}$$ are the target and projectile atomic numbers. In conclusion, for the more than 100 cross section curves that we use to find the scaling rules, the scaling law predicts cross sections within a little over a factor of 2 on average.« less

Measured microwave scattering cross sections of three meteorite specimens

NASA Technical Reports Server (NTRS)

Hughes, W. E.

1972-01-01

Three meteorite specimens were used in a microwave scattering experiment to determine the scattering cross sections of stony meteorites and iron meteorites in the frequency range from 10 to 14 GHz. The results indicate that the stony meteorites have a microwave scattering cross section that is 30 to 50 percent of their projected optical cross section. Measurements of the iron meteorite scattering were inconclusive because of specimen surface irregularities.

Asymptotic form for the cross section for the Coulomb interacting rearrangement collisions.

NASA Technical Reports Server (NTRS)

Omidvar, K.

1973-01-01

It is shown that in a rearrangement collision leading to the formation of highly excited hydrogenlike states the cross section at high energies behaves as 1/n-squared, with n the principal quantum number, thus invalidating the Brinkman-Kramers approximation for large n. Similarly, in high-energy inelastic electron-hydrogenlike-atom collisions the exchange cross section for sufficiently large n dominates the direct excitation cross section.

Study of the angular coefficients and corresponding helicity cross sections of the W boson in hadron collisions

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

Strologas, John; Errede, Steven; Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801

We present the standard model prediction for the eight angular coefficients of the W boson, which completely describes its differential cross section in hadron collisions. These coefficients are ratios of the W helicity cross sections and the total unpolarized cross section. We also suggest a technique to experimentally extract the coefficients, which we demonstrate in the Collins-Soper azimuthal-angle analysis.

Fragmentation Cross Sections of 290 and 400 MeV/nucleon 12C Beamson Elemental Targets

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

Zeitlin, C.; Guetersloh, S.; Heilbronn, L.

Charge-changing and fragment production cross sections at 0circ have been obtained for interactions of 290 MeV/nucleon and 400MeV/nucleon carbon beams with C, CH2, Al, Cu, Sn, and Pb targets. Thesebeams are relevant to cancer therapy, space radiation, and the productionof radioactive beams. We compare to previously published results using Cand CH2 targets at similar beam energies. Due to ambiguities arising fromthe presence of multiple fragments on many events, previous publicationshave reported only cross sections for B and Be fragments. In this work wehave extracted cross sections for all fragment species, using dataobtained at three distinct values of angular acceptance, supplementedmore » bydata taken with the detector stack placed off the beam axis. A simulationof the experiment with the PHITS Monte Carlo code shows fair agreementwith the data obtained with the large acceptance detectors, but agreementis poor at small acceptance. The measured cross sections are alsocompared to the predictions of the one-dimensional cross section modelsEPAX2 and NUCFRG2; the latter is presently used in NASA's space radiationtransport calculations. Though PHITS and NUCFRG2 reproduce thecharge-changing cross sections with reasonable accuracy, none of themodels is able to accurately predict the fragment cross sections for allfragment species and target materials.« less

Extracting Cross-Sectional Clinical Images Based on Their Principal Axes of Inertia

PubMed Central

Fan, Yuzhou; Djuric, Marija; Li, Zhiyu; Antonijevic, Djordje; Milenkovic, Petar; Sun, Yueyang; Li, Ruining

2017-01-01

Cross-sectional imaging is considered the gold standard in diagnosing a range of diseases. However, despite its widespread use in clinical practice and research, no widely accepted method is available to reliably match cross-sectional planes in several consecutive scans. This deficiency can impede comparison between cross-sectional images and ultimately lead to misdiagnosis. Here, we propose and demonstrate a method for finding the same imaging plane in images obtained during separate scanning sessions. Our method is based on the reconstruction of a “virtual organ” from which arbitrary cross-sectional images can be extracted, independent of the axis orientation in the original scan or cut; the key is to establish unique body coordinates of the organ from its principal axes of inertia. To verify our method a series of tests were performed, and the same cross-sectional plane was successfully extracted. This new approach offers clinicians access, after just a single scanning session, to the morphology and structure of a lesion through cross-sectional images reconstructed along arbitrary axes. It also aids comparable detection of morphological and structural changes in the same imaging plane from scans of the same patient taken at different times—thus potentially reducing the misdiagnosis rate when cross-sectional images are interpreted. PMID:29410714

Extracting Cross-Sectional Clinical Images Based on Their Principal Axes of Inertia.

PubMed

Fan, Yuzhou; Luo, Liangping; Djuric, Marija; Li, Zhiyu; Antonijevic, Djordje; Milenkovic, Petar; Sun, Yueyang; Li, Ruining; Fan, Yifang

2017-01-01

Cross-sectional imaging is considered the gold standard in diagnosing a range of diseases. However, despite its widespread use in clinical practice and research, no widely accepted method is available to reliably match cross-sectional planes in several consecutive scans. This deficiency can impede comparison between cross-sectional images and ultimately lead to misdiagnosis. Here, we propose and demonstrate a method for finding the same imaging plane in images obtained during separate scanning sessions. Our method is based on the reconstruction of a "virtual organ" from which arbitrary cross-sectional images can be extracted, independent of the axis orientation in the original scan or cut; the key is to establish unique body coordinates of the organ from its principal axes of inertia. To verify our method a series of tests were performed, and the same cross-sectional plane was successfully extracted. This new approach offers clinicians access, after just a single scanning session, to the morphology and structure of a lesion through cross-sectional images reconstructed along arbitrary axes. It also aids comparable detection of morphological and structural changes in the same imaging plane from scans of the same patient taken at different times-thus potentially reducing the misdiagnosis rate when cross-sectional images are interpreted.

Cross-Sectional Analysis of Longitudinal Mediation Processes.

PubMed

O'Laughlin, Kristine D; Martin, Monica J; Ferrer, Emilio

2018-01-01

Statistical mediation analysis can help to identify and explain the mechanisms behind psychological processes. Examining a set of variables for mediation effects is a ubiquitous process in the social sciences literature; however, despite evidence suggesting that cross-sectional data can misrepresent the mediation of longitudinal processes, cross-sectional analyses continue to be used in this manner. Alternative longitudinal mediation models, including those rooted in a structural equation modeling framework (cross-lagged panel, latent growth curve, and latent difference score models) are currently available and may provide a better representation of mediation processes for longitudinal data. The purpose of this paper is twofold: first, we provide a comparison of cross-sectional and longitudinal mediation models; second, we advocate using models to evaluate mediation effects that capture the temporal sequence of the process under study. Two separate empirical examples are presented to illustrate differences in the conclusions drawn from cross-sectional and longitudinal mediation analyses. Findings from these examples yielded substantial differences in interpretations between the cross-sectional and longitudinal mediation models considered here. Based on these observations, researchers should use caution when attempting to use cross-sectional data in place of longitudinal data for mediation analyses.

Single- and double-photoionization cross sections of atomic nitrogen from threshold to 31 A

NASA Technical Reports Server (NTRS)

Samson, James A. R.; Angel, G. C.

1990-01-01

The relative photoionization cross section of atomic nitrogen for the production of singly and doubly charged ions has been measured from 44.3 to 275 A and from 520 to 852 A. The results have been made absolute by normalization to one-half of the molecular nitrogen cross section at short wavelengths. The smoothed atomic nitrogen cross sections sigma can be accurately represented, at short wavelengths, by the equation sigma(Mb) = 36,700 x (E exp-2.3) as a function of the photon energy E (eV), thereby allowing the cross sections to be extrapolated to the nitrogen K edge at 31 A.

Analysis of the effectiveness of various cross-sections in large-span post-tensioned ceilings

NASA Astrophysics Data System (ADS)

Bednarz, K.

2018-03-01

The correct construction of large span, slim post-tensioned concrete slabs is conditioned by an appropriate cross-section selection. It is generally accepted that the thinnest slab can be constructed using the full cross-section as the largest compression stress storage. However, completely different cross-sections may help to overcome large spans. The paper presents the results of the computational analysis of several types of cross-sections (full, with internal relieving inserts and ribbed) in the application to a post-tensioned slab with a span of 15.0m. Based on the results presented, appropriate conclusions were drawn.

Calculation of the Coulomb Fission Cross Sections for Pb-Pb and Bi-Pb Interactions at 158 A GeV

NASA Technical Reports Server (NTRS)

Poyser, William J.; Ahern, Sean C.; Norbury, John W.; Tripathi, R. K.

2002-01-01

The Weizsacker-Williams (WW) method of virtual quanta is used to make approximate cross section calculations for peripheral relativistic heavy-ion collisions. We calculated the Coulomb fission cross sections for projectile ions of Pb-208 and Bi-209 with energies of 158 A GeV interacting with a Pb-208 target. We also calculated the electromagnetic absorption cross section for Pb-208 ion interacting as described. For comparison we use both the full WW method and a standard approximate WW method. The approximate WW method in larger cross sections compared to the more accurate full WW method.

Lidar cross-sections of soot fractal aggregates: Assessment of equivalent-sphere models

NASA Astrophysics Data System (ADS)

Ceolato, Romain; Gaudfrin, Florian; Pujol, Olivier; Riviere, Nicolas; Berg, Matthew J.; Sorensen, Christopher M.

2018-06-01

This work assesses the ability of equivalent-sphere models to reproduce the optical properties of soot aggregates relevant for lidar remote sensing, i.e. the backscattering and extinction cross sections. Lidar cross-sections are computed with a spectral discrete dipole approximation model over the visible-to-infrared (400-5000 nm) spectrum and compared with equivalent-sphere approximations. It is shown that the equivalent-sphere approximation, applied to fractal aggregates, has a limited ability to calculate such cross-sections well. The approximation should thus be used with caution for the computation of broadband lidar cross-sections, especially backscattering, at small and intermediate wavelengths (e.g. UV to visible).

Electron capture cross sections by O+ from atomic He

NASA Astrophysics Data System (ADS)

Joseph, Dwayne C.; Saha, Bidhan C.

2009-11-01

The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections

Single-level resonance parameters fit nuclear cross-sections

NASA Technical Reports Server (NTRS)

Drawbaugh, D. W.; Gibson, G.; Miller, M.; Page, S. L.

1970-01-01

Least squares analyses of experimental differential cross-section data for the U-235 nucleus have yielded single level Breit-Wigner resonance parameters that fit, simultaneously, three nuclear cross sections of capture, fission, and total.

[Effect of resin infiltration on microhardness of artificial caries lesions].

PubMed

Liu, Yonghong; Deng, Hui; Tang, Longmei; Zhang, Zhiyong

2015-12-01

To compare the changes of enamel surface and cross-sectional microhardness of artificial caries immediately and after the twice demineralization through coating resin infiltration, fluoride varnish and fissure sealant. A total of forty bovine lower incisors enamel samples with artificial caries lesions by the demineralization liquid were used in the experiment. The specimens were then randomly divided into four groups as group A(resin infiltration), B(fluoride varnish), C (fissure sealant), D(control), 10 specimens in each group. The samples were sectioned vertically into two halves through the centre. One half of each sample the surface and cross-sectional microhardness was measured. The other half was put into demineralization liquid for 14 days, then the surface and cross-sectional microhardness was measured again. The cross section morphology of the samples was observed by scanning electron microscope. The surface of enamel had the highest microhardness value, and with the increase of cross- sectional depth, the microhardness value declined gradually. Variance analysis showed that the difference was statistically significant in the cross-section of different depth among the four groups(P<0.05). The microhardness values of the surface and the cross- section at 40 µm of each group in immediate measure showed the values were significantly higher in group A, B and C than in group D. There was no significant difference in the microhardness value of cross-section at 80 µm between group A[(324 ± 17) kg/mm(2)] and group C[(316 ± 20) kg/mm(2)], but they were significantly higher than group D. There was no significant difference between group B[(303 ± 13) kg/mm(2)] and group D[(294 ± 23) kg/mm(2)]. At 120 µm level, the microhardness value of group A was significantly higher than those of the other three groups. After the twice demineralization, the enamel surface microhardness value of the specimens was the same as the first measurement. In the cross-section at 40 µm level, the microhardness value was equal to the value of cross-section at 80 µm level of the first measurement. In the cross- section at 80 µm and 120 µm level, the microhardness value of group A was significantly higher than those of the other three groups. Resin infiltration can effectively strengthen microhardness of enamel surface and cross-section of different depth of artificial caries.

Examination of the 22C radius determination with interaction cross sections

NASA Astrophysics Data System (ADS)

Nagahisa, T.; Horiuchi, W.

2018-05-01

A nuclear radius of 22C is investigated with the total reaction cross sections at medium- to high-incident energies in order to resolve the radius puzzle in which two recent interaction cross-section measurements using 1H and 12C targets show the quite different radii. The cross sections of 22C are calculated consistently for these target nuclei within a reliable microscopic framework, the Glauber theory. To describe appropriately such a reaction involving a spatially extended nucleus, the multiple scattering processes within the Glauber theory are fully taken into account, that is, the multidimensional integration in the Glauber amplitude is evaluated using a Monte Carlo technique without recourse to the optical-limit approximation. We discuss the sensitivity of the spatially extended halo tail to the total reaction cross sections. The root-mean-square matter radius obtained in this study is consistent with that extracted from the recent cross-section measurement on 12C target. We show that the simultaneous reproduction of the two recent measured cross sections is not feasible within this framework.

Measurement of the Am 242 m neutron-induced reaction cross sections

DOE PAGES

Buckner, M. Q.; Wu, C. Y.; Henderson, R. A.; ...

2017-02-17

The neutron-induced reaction cross sections of 242mAm were measured at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array along with a compact parallel-plate avalanche counter for fission-fragment detection. A new neutron-capture cross section was determined, and the absolute scale was set according to a concurrent measurement of the well-known 242mAm(n,f) cross section. The (n,γ) cross section was measured from thermal energy to an incident energy of 1 eV at which point the data quality was limited by the reaction yield in the laboratory. Our new 242mAm fission cross section was normalized to ENDF/B-VII.1 tomore » set the absolute scale, and it agreed well with the (n,f) cross section from thermal energy to 1 keV. Lastly, the average absolute capture-to-fission ratio was determined from thermal energy to E n = 0.1 eV, and it was found to be 26(4)% as opposed to the ratio of 19% from the ENDF/B-VII.1 evaluation.« less

Mixed Legendre moments and discrete scattering cross sections for anisotropy representation

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

Calloo, A.; Vidal, J. F.; Le Tellier, R.

2012-07-01

This paper deals with the resolution of the integro-differential form of the Boltzmann transport equation for neutron transport in nuclear reactors. In multigroup theory, deterministic codes use transfer cross sections which are expanded on Legendre polynomials. This modelling leads to negative values of the transfer cross section for certain scattering angles, and hence, the multigroup scattering source term is wrongly computed. The first part compares the convergence of 'Legendre-expanded' cross sections with respect to the order used with the method of characteristics (MOC) for Pressurised Water Reactor (PWR) type cells. Furthermore, the cross section is developed using piecewise-constant functions, whichmore » better models the multigroup transfer cross section and prevents the occurrence of any negative value for it. The second part focuses on the method of solving the transport equation with the above-mentioned piecewise-constant cross sections for lattice calculations for PWR cells. This expansion thereby constitutes a 'reference' method to compare the conventional Legendre expansion to, and to determine its pertinence when applied to reactor physics calculations. (authors)« less

Thermoelastic damping in microrings with circular cross-section

NASA Astrophysics Data System (ADS)

Li, Pu; Fang, Yuming; Zhang, Jianrun

2016-01-01

Predicting thermoelastic damping (TED) is crucial in the design of high Q micro-resonators. Microrings are often critical components in many micro-resonators. Some analytical models for TED in microrings have already been developed in the past. However, the previous works are limited to the microrings with rectangular cross-section. The temperature field in the rectangular cross-section is one-dimensional. This paper deals with TED in the microrings with circular cross-section. The temperature field in the circular cross-section is two-dimensional. This paper first presents a 2-D analytical model for TED in the microrings with circular cross-section. Only the two-dimensional heat conduction in the circular cross-section is considered. The heat conduction along the circumferential direction of the microring is neglected in the 2-D model. Then the 2-D model has been extended to cover the circumferential heat conduction, and a 3-D analytical model for TED has been developed. The analytical results from the present 2-D and 3-D models show good agreement with the numerical results of FEM model. The limitations of the present 2-D analytical model are assessed.

Measurement of 208Pb(n ,γ )209Pb Maxwellian averaged neutron capture cross section

NASA Astrophysics Data System (ADS)

Weissman, L.; Tessler, M.; Arenshtam, A.; Eliyahu, I.; Halfon, S.; Guerrero, C.; Kaizer, B.; Kijel, D.; Kreisel, A.; Palchan, T.; Paul, M.; Perry, A.; Schimel, G.; Silverman, I.; Shor, A.; Tamim, N.; Vaintraub, S.

2017-07-01

The doubly magic 208Pb nucleus is a bottleneck at the termination of the s -process path due to its very low neutron capture cross section. This cross section is also important for the decomposition of s , r processes and U/Th radiogenic decay contributions to the Pb-Bi solar abundances. The 208Pb(n ,γ )209Pb cross section was measured at the Soreq Applied Research Accelerator Facility Phase I using an intense quasi-Maxwellian neutron source produced by irradiation of the liquid-lithium target with a 1.5-mA continuous-wave proton beam at 1.94 MeV. The cross section was measured by counting the β activity from the irradiated lead target. The measurement allowed us to evaluate the Maxwellian averaged cross section (MACS) at 30 keV obtaining a value of 0.33(2) mb. This has been compared with the earlier activation and time-of-flight measurements found in the literature. The MACS cross-sectional value of the 63Cu(n ,γ )64Cu reaction was determined in the same experiment and is compared to a recent published value.

Multidimensional analysis of fast-spectrum material replacement measurements for systematic estimation of cross section uncertainties

NASA Technical Reports Server (NTRS)

Klann, P. G.; Lantz, E.; Mayo, W. T.

1973-01-01

A series of central core and core-reflector interface sample replacement experiments for 16 materials performed in the NASA heavy-metal-reflected, fast spectrum critical assembly (NCA) were analyzed in four and 13 groups using the GAM 2 cross-section set. The individual worths obtained by TDSN and DOT multidimensional transport theory calculations showed significant differences from the experimental results. These were attributed to cross-section uncertainties in the GAM 2 cross sections. Simultaneous analysis of the measured and calculated sample worths permitted separation of the worths into capture and scattering components which systematically provided fast spectrum averaged correction factors to the magnitudes of the GAM 2 absorption and scattering cross sections. Several Los Alamos clean critical assemblies containing Oy, Ta, and Mo as well as one of the NCA compositions were reanalyzed using the corrected cross sections. In all cases the eigenvalues were significantly improved and were recomputed to within 1 percent of the experimental eigenvalue. A comparable procedure may be used for ENDF cross sections when these are available.

Single and double capture in F9+ + Ar collisions: Comparison of total capture with capture occurring from the Ar K shell

NASA Astrophysics Data System (ADS)

La Mantia, David; Kumara, Nuwan; Kayani, Asghar; Simon, Anna; Tanis, John

2016-05-01

Total cross sections for single and double capture, as well as the corresponding cross sections for capture resulting in the emission of an Ar K x ray, were measured. This work was performed at Western Michigan University with the use of the tandem Van de Graaff accelerator. A 45 MeV beam of fully-stripped fluorine ions was collided with argon gas molecules in a differentially pumped cell. Surface barrier detectors were used to observe the charge changed projectiles and a Si(Li) x-ray detector, placed at 90o to the incident beam, were used to measure coincidences with Ar K x rays. The total capture cross sections are compared to previously measured cross sections in the existing literature. The coincidence cross sections, considerably smaller than the total cross sections, are found to be nearly equal for single and double capture in contrast to the total cross sections, which vary by about an order of magnitude. Possible reasons for this behavior are discussed. Supported in part by the NSF.

On the correlation of absorption cross-section with plasmonic color generation.

PubMed

Rezaei, Soroosh Daqiqeh; Ho, Jinfa; Ng, Ray Jia Hong; Ramakrishna, Seeram; Yang, Joel K W

2017-10-30

Through numerical simulations, we investigate the correlation between the absorption cross-section and the color saturation of plasmonic nanostructures of varying density. Understanding this correlation, enables the prediction of an optimal nanostructure separation, or combinations of different nanostructure sizes for plasmonic color printing applications. Here, we use metal-insulator-metal (MIM) aluminum nanostructures that support gap-plasmons. Large absorption cross-sections were observed that exceed twelve times the physical cross-section of the nanostructure disks. We derive a set of equations to determine the optimal separation for a periodic array using the absorption cross-section of an individual structure to realize saturated colors. Using the optimum pitch and enabled by the large absorption cross-sections of our structures, we employ color mixing strategies to realize a wider color gamut. The simulated color gamut exceeds the sRGB gamut for some colors, and includes dark tones. Color mixing using structures with large absorption cross-sections is a practical approach to generate a broad range of colors, in comparison to fabricating structures with continuously varying sizes.

Shell-model computed cross sections for charged-current scattering of astrophysical neutrinos off 40Ar

NASA Astrophysics Data System (ADS)

Kostensalo, Joel; Suhonen, Jouni; Zuber, K.

2018-03-01

Charged-current (anti)neutrino-40Ar cross sections for astrophysical neutrinos have been calculated. The initial and final nuclear states were calculated using the nuclear shell model. The folded solar-neutrino scattering cross section was found to be 1.78 (23 ) ×10-42cm2 , which is higher than what the previous papers have reported. The contributions from the 1- and 2- multipoles were found to be significant at supernova-neutrino energies, confirming the random-phase approximation (RPA) result of a previous study. The effects of neutrino flavor conversions in dense stellar matter (matter oscillations) were found to enhance the neutrino-scattering cross sections significantly for both the normal and inverted mass hierarchies. For the antineutrino scattering, only a small difference between the nonoscillating and inverted-hierarchy cross sections was found, while the normal-hierarchy cross section was 2-3 times larger than that of the nonoscillating cross section, depending on the adopted parametrization of the Fermi-Dirac distribution. This property of the supernova-antineutrino signal could probably be used to distinguish between the two hierarchies in megaton LAr detectors.