7,547 research outputs found
Form Factors for Lambda_b -> Lambda Transitions in SCET
We present a systematic discussion of Lambda_b -> Lambda transition form
factors in the framework of soft-collinear effective theory (SCET). The
universal soft form factor, which enters the symmetry relations in the limit of
large recoil energy, is calculated from a sum-rule analysis of a suitable SCET
correlation function. The same method is applied to derive the leading
corrections from hard-collinear gluon exchange at first order in the strong
coupling constant. We present numerical estimates for form factors and
form-factor ratios and their impact on decay observables in Lambda_b -> Lambda
mu^+ mu^- decays.Comment: 2+29 pages, 9 figures. Corrections in Sections 3.2 and 4 and Appendix
D.1. Conclusions do not change. Erratum to appear in PR
Synthesis of H<sub>x</sub>Li<sub>1-x</sub>LaTiO<sub>4</sub> from quantitative solid-state reactions at room temperature
The layered perovskite HLaTiO4 reacts stoichiometrically with LiOH·H2O at room temperature to give targeted compositions in the series HxLi1-xLaTiO4. Remarkably, the Li+ and H+ ions are quantitatively exchanged in the solid state and this allows stoichiometric control of ion exchange for the first time in this important series of compounds
Effects of deflected thrust on the longitudinal aerodynamic characteristics of a close-coupled wing-canard configuration
The effects of power on the longitudinal aerodynamic characteristics of a close-coupled wing-canard fighter configuration with partial-span rectangular nozzles at the trailing edge of the wing were investigated. Data were obtained on a basic wing-strake configuration for nozzle and flap deflections from 0 deg to 30 deg and for nominal thrust coefficients from 0 to 0.30. The model was tested over an angle-of-attack range from -2 deg to 40 deg at Mach numbers of 0.15 and 0.18. Results show substantial improvements in lift-curve slope, in maximum lift, and in drag-due-to-lift efficiency when the canard and strakes have been added to the basic wing-fuselage (wing-alone) configuration. Addition of power increased both lift-curve slope and maximum lift, improved longitudinal stability, and reduced drag due to lift on both the wing-canard and wing-canard-strake configurations. These beneficial effects are primarily derived from boundary-layer control due to moderate thrust coefficients which delay flow separation on the nozzle and inboard portion of the wing flaps
A general two-sector model of endogenous growth with human and physical capital: balanced growth and transitional dynamics
Economic development ; Human capital
SSB-1 of the yeast Saccharomyces cerevisiae is a nucleolar-specific, silver-binding protein that is associated with the snR10 and snR11 small nuclear RNAs
SSB-1, the yeast single-strand RNA-binding protein, is demonstrated to be a yeast nucleolar-specific, silver-binding protein. In double-label immunofluorescence microscopy experiments antibodies to two other nucleolar proteins, RNA Pol I 190-kD and fibrillarin, were used to reveal the site of rRNA transcription; i.e., the fibrillar region of the nucleolus. SSB-1 colocalized with fibrillarin in a double-label immunofluorescence mapping experiment to the yeast nucleolus. SSB-1 is located, though, over a wider region of the nucleolus than the transcription site marker. Immunoprecipitations of yeast cell extracts with the SSB-1 antibody reveal that in 150 mM NaCl SSB-1 is bound to two small nuclear RNAs (snRNAs). These yeast snRNAs are snR10 and snR11, with snR10 being predominant. Since snR10 has been implicated in pre-rRNA processing, the association of SSB-1 and snR10 into a nucleolar snRNP particle indicates SSB-1 involvement in rRNA processing as well. Also, another yeast protein, SSB-36-kD, isolated by single- strand DNA chromatography, is shown to bind silver under the conditions used for nucleolar-specific staining. It is, most likely, another yeast nucleolar protein
Light-Cone Distribution Amplitudes for Heavy-Quark Hadrons
We construct parametrizations of light-cone distribution amplitudes (LCDAs)
for B-mesons and Lambda_b-baryons that obey various theoretical constraints,
and which are simple to use in factorization theorems relevant for
phenomenological applications in heavy-flavour physics. In particular, we find
the eigenfunctions of the Lange-Neubert renormalization kernel, which allow for
a systematic implementation of renormalization-group evolution effects for both
B-meson and \Lambda_b-baryon decays. We also present a new strategy to
construct LCDA models from momentum-space projectors, which can be used to
implement Wandzura-Wilczek--like relations, and which allow for a comparison
with theoretical approaches that go beyond the collinear limit for the
light-quark momenta in energetic heavy-hadron decays.Comment: 39 pages, 11 figure
Low-speed power effects on advanced fighter configurations with two-dimensional deflected thrust
Wind-tunnel studies at the Langley Research Center have shown that significant increases in maximum lift coefficient and stability and decreases in drag due to lift are obtained when two-dimensional vectored thrust is used in conjuction with a close-coupled canard. The configuration tested was somewhat above the theoretical minimum drag due to lift because of the sharp leading edge on the biconvex airfoil used on the wing and canard. An effort to design a new configuration which will approach the minimum drag due to lift while maintaining high-lift configurations was completed. The resulting model will incorporate a realistic planform, airfoil section, and twist for a transonic maneuvering configuration
Management of therapist directiveness in integrative psychotherapy: A corpus-assisted discourse study
Healthcare practitioners often face the dilemma of whether to provide advice during medical consultations due to concerns around affecting patients’ autonomy in decision making. Healthcare practitioners’ directiveness in patient–practitioner interactions may influence the success of medical consultations. Research has revealed that healthcare practitioners employ various communicative strategies and linguistic patterns to manage directiveness in medical consultations, such as the notions of likelihood and uncertainty, use of information, and politeness. Nonetheless, few scholars have examined how psychotherapists manage directiveness in counseling or psychotherapy sessions. Directives are inevitable speech acts in counseling or psychotherapy. Therapists may encounter challenges when producing directives, such as preventing clients from seeking their own solutions or clients becoming excessively dependent on therapists’ suggestions. Drawing upon the systems of mood and modality in systemic functional linguistics, this article employs a corpus-assisted approach to investigate therapists’ directives in terms of phraseological patterns, use of modality, and corresponding interpersonal meanings. Results reveal that therapists tend to manage directiveness by forming indicative directives and using low-value modulation modality. This article is the first corpus-assisted study to contribute to an understanding of therapist directiveness in psychotherapy from a lexico-grammatical perspective.
Molecular Dynamics Computer Simulation of the Dynamics of Supercooled Silica
We present the results of a large scale computer simulation of supercooled
silica. We find that at high temperatures the diffusion constants show a
non-Arrhenius temperature dependence whereas at low temperature this dependence
is also compatible with an Arrhenius law. We demonstrate that at low
temperatures the intermediate scattering function shows a two-step relaxation
behavior and that it obeys the time temperature superposition principle. We
also discuss the wave-vector dependence of the nonergodicity parameter and the
time and temperature dependence of the non-Gaussian parameter.Comment: 5 pages, Latex, 6 postscript figure
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