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The SBASE protein domain library, Release 4.0: a collection of annotated protein sequence segments.

Murvai, J; Gabrielian, A; Fábián, P; Hátsagi, Z; Degtyarenko, K; Hegyi, H; Pongor, S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/01/1996 Português
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SBASE 4.0 is the fourth release of SBASE, a collection of annotated protein domain sequences that represent various structural, functional, ligand binding and topogenic segments of proteins. SBASE was designed to facilitate the detection of functional homologies and can be searched with standard database search tools, such as FASTA and BLAST3. The present release contains 61 137 entries provided with standardized names and cross-referenced to all major protein, nucleic acid and sequence pattern collections. The entries are clustered into 13 155 groups in order to facilitate detection of distant similarities. SBASE 4.0 is freely available by anonymous ftp file transfer from ftp.icgeb.trieste.it. Individual records can be retrieved with the gopher server at icgeb.trieste.it and with a World Wide Web server at http://www.icgeb.trieste.it. Automated searching of SBASE with BLAST can be carried out with the electronic mail server sbase@icgeb.trieste.it, which now also provides a graphic representation of the homologies. A related mail server, domain@hubi.abc.hu, assigns SBASE domain homologies on the basis of SWISS-PROT searches.

O-GLYCBASE version 4.0: a revised database of O-glycosylated proteins.

Gupta, R; Birch, H; Rapacki, K; Brunak, S; Hansen, J E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/01/1999 Português
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O-GLYCBASE is a database of glycoproteins with O-linked glycosylation sites. Entries with at least one experimentally verified O-glycosylation site have been compiled from protein sequence databases and literature. Each entry contains information about the glycan involved, the species, sequence, a literature reference and http-linked cross-references to other databases. Version 4.0 contains 179 protein entries, an approximate 15% increase over the last version. Sequence logos representing the acceptor specificity patterns for GalNAc, GlcNAc, mannosyl and xylosyl transferases are shown. The O-GLYCBASE database is available through the WWW at http://www.cbs.dtu.dk/databases/OGLYCBASE/

The structure of alfalfa mosaic virus capsid protein assembled as a T=1 icosahedral particle at 4.0-A resolution.

Kumar, A; Reddy, V S; Yusibov, V; Chipman, P R; Hata, Y; Fita, I; Fukuyama, K; Rossmann, M G; Loesch-Fries, L S; Baker, T S; Johnson, J E
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /10/1997 Português
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K. Fukuyama, S. S. Abdel-Meguid, J. E. Johnson, and M. G. Rossmann (J. Mol. Biol. 167:873-984, 1983) reported the structure of alfalfa mosaic virus assembled from the capsid protein as a T=1 icosahedral empty particle at 4.5-A resolution. The information contained in the structure included the particle size, protein shell thickness, presence of wide holes at the icosahedral fivefold axes, and a proposal that the capsid protein adopts a beta-barrel structure. In the present work, the X-ray diffraction data of Fukuyama et al. as well as the data subsequently collected by I. Fita, Y. Hata, and M. G. Rossmann (unpublished) were reprocessed to 4.0-A resolution, and the structure was solved by molecular replacement. The current structure allowed the tracing of the polypeptide chain of the capsid protein confirming the beta-sandwich fold and provides information on intersubunit interactions in the particle. However, it was not possible to definitively assign the amino acid sequence to the side chain density at 4-A resolution. The particle structure was also determined by cryoelectron microscopy and image reconstruction methods and found to be in excellent agreement with the X-ray model.

ProTherm, version 4.0: thermodynamic database for proteins and mutants

Bava, K. Abdulla; Gromiha, M. Michael; Uedaira, Hatsuho; Kitajima, Koji; Sarai, Akinori
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
Publicado em 01/01/2004 Português
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Release 4.0 of ProTherm, thermodynamic database for proteins and mutants, contains ∼14 500 numerical data (∼450% of the first version) of several thermodynamic parameters along with experimental methods and conditions, and structural, functional and literature information. The sequence and structural information of proteins is connected with thermodynamic data through links between entries in Protein Data Bank, Protein Information Resource and SWISS-PROT and the data in ProTherm. We have separated the Gibbs free energy change obtained at extrapolated temperature from the data on denaturation temperature measured by the thermal denaturation method. We have added the statistics of amino acid replacements and links to homologous structures to each protein. Further, we have improved the search and display options to enhance search capability through the web interface. ProTherm is freely available at http://gibk26.bse.kyutech.ac.jp/jouhou/Protherm/protherm.html.

Projection structure of NhaA, a secondary transporter from Escherichia coli, at 4.0 A resolution.

Williams, K A; Geldmacher-Kaufer, U; Padan, E; Schuldiner, S; Kühlbrandt, W
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 01/07/1999 Português
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Electron cryomicroscopy of frozen-hydrated two-dimensional crystals of NhaA, a Na+/H+ antiporter from Escherichia coli predicted to have 12 transmembrane alpha-helices, has facilitated the calculation of a projection map of NhaA at 4.0 A resolution. NhaA was homologously expressed in E.coli with a His6 tag, solubilized in dodecyl maltoside and purified in a single step using Ni2+ affinity chromatography. Two-dimensional crystals were obtained after reconstitution of purified protein with E.coli lipids. The projection map reveals that this secondary transporter has a highly asymmetric structure in projection. NhaA exhibits overall dimensions of approximately 38x48 A with a ring-shaped density feature probably corresponding to a bundle of tilted helices, adjacent to an elongated region of density containing several peaks indicative of transmembrane helices. Two crystal forms with p22121 symmetry show tightly packed dimers of NhaA which differ in the interactions between adjacent dimers. This work provides the first direct glimpse into the structure of a secondary transporter.

Synthesis and coordination chemistry of 1,4,7,10,13-pentakis( 2-hydroxyethyl)-1,4,7,10,13-pentaazacyclopentadecane: a five armed pendant donor macrocycle

Walters, K.; Buntine, M.; Lincoln, S.; Wainwright, K.
Fonte: Royal Soc Chemistry Publicador: Royal Soc Chemistry
Tipo: Artigo de Revista Científica
Publicado em //2002 Português
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Synthesis of the five armed pendant donor macrocycle 1,4,7,10,13-pentakis(2-hydroxyethyl)-1,4,7,10,13- pentaazacyclopentadecane (phec15) has been achieved by reaction of 1,4,7,10,13-pentaazacyclopentadecane ([15]aneN₅) with ethylene oxide in the absence of light and oxygen over an eight day period. The first three pKa values for phec15 have been determined by potentiometric titration (I = 0.1 mol dm⁻³ NEt₄ClO₄) to be 8.51 ± 0.01, 7.57 ± 0.01 and 3.74 ± 0.01, respectively, and the final two are < 2.3. The stability constants (log(K/dm³ mol⁻¹) for [M(phec15]²⁺ complexes in aqueous solution where M = Co(II), Cu(II), Zn(II), Cd(II) and Pb(II) are 7.45 ± 0.03, 14.69 ± 0.02, 8.47 ± 0.01, 12.57 ± 0.03, and 10.35 ± 0.03, respectively. Gas phase ab initio modelling predicts that phec15 adopts the trans-I configuration, by virtue of linked hydrogen bonding between the five pendant hydroxyl groups, and that [Ba(phec15)]²⁺ and [Sr(phec15)]²⁺ are ten coordinate with an approximately pentagonal prismatic structure in which the plane of the five oxygen atoms is rotated either clockwise or anticlockwise with respect to the nitrogen atom plane, giving rise to Λ and Δ enantiomers, respectively. Variable temperature ¹³C{¹H} NMR spectra support these structural predictions and in the case of [Ba(phec15)]²⁺ complete lineshape analysis gave the kinetic parameters k = (4.0 ± 0.3) × 10⁴s⁻¹...

Search for point sources of ultra-high-energy cosmic rays above 4.0 x 1019 eV using a maximum likelihood ratio test

Abbasi, R.; Abu-Zayyad, T.; Amman, J.; Archbold, G.; Atkins, R.; Bellido Caceres, J.; Belov, K.; Belz, J.; BenZvi, S.; Bergman, D.; Boyer, J.; Burt, G.; Cao, Z.; Clay, R.; Connolly, B.; Dawson, B.; Deng, W.; Farrar, G.; Fedorova, Y.; Findlay, J.; et al.
Fonte: Univ Chicago Press Publicador: Univ Chicago Press
Tipo: Artigo de Revista Científica
Publicado em //2005 Português
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We present the results of a search for cosmic-ray point sources at energies in excess of 4.0 × 1019 eV in the combined data sets recorded by the Akeno Giant Air Shower Array and High Resolution Fly's Eye stereo experiments. The analysis is based on a maximum likelihood ratio test using the probability density function for each event rather than requiring an a priori choice of a fixed angular bin size. No statistically significant clustering of events consistent with a point source is found.; R. U. Abbasi, T. Abu-Zayyad, J. F. Amann, G. Archbold, R. Atkins, J. A. Bellido, K. Belov, J. W. Belz, S. Y. Ben-Zvi, D. R. Bergman, J. H. Boyer, G. W. Burt, Z. Cao, R. W. Clay, B. M. Connolly, B. R. Dawson, W. Deng, G. R. Farrar, Y. Fedorova, J. Findlay, C. B. Finley, W. F. Hanlon, C. M. Hoffman, M. H. Holzscheiter, G. A. Hughes, P. Hüntemeyer, C. C. H. Jui, K. Kim, M. A. Kirn, B. C. Knapp, E. C. Loh, M. M. Maestas, N. Manago, E. J. Mannel, L. J. Marek, K. Martens, J. A. J. Matthews, J. N. Matthews, A. O'Neill, C. A. Painter, L. Perera, K. Reil, R. Riehle, M. D. Roberts, M. Sasaki, S. R. Schnetzer, M. Seman, K. M. Simpson, G. Sinnis, J. D. Smith, R. Snow, P. Sokolsky, C. Song, R. W. Springer, B. T. Stokes, J. R. Thomas, S. B. Thomas, G. B. Thomson...

The prognostic significance of tumor vascularity in intermediate-thickness (0.76-4.0 mm thick) skin melanoma. A quantitative histologic study.

Srivastava, A.; Laidler, P.; Davies, R. P.; Horgan, K.; Hughes, L. E.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /11/1988 Português
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The vascularity of 20 primary skin melanomas was assessed histologically. These cases were selected from patients with intermediate thickness melanomas (0.76-4.0 mm thick) treated surgically to provide two groups of ten patients. One group had no evidence of recurrence with a minimum follow-up of 9 years. The second group of ten patients developed locoregional or systemic metastasis under follow-up, and seven of these patients died of disseminated melanoma. Age, sex, Breslow's tumor thickness, and Clark's level of invasion were similar in the two groups. Vascular quantitation was carried out by image analysis after vascular definition by Ulex europaeus-I agglutinin staining. The percentage vascular area at the tumor base in the recurrence group was more than twice that in the recurrence-free group. This study suggests that increased vascularity at the tumor base may have prognostic significance in intermediate thickness melanomas.

Separated Structure Functions for Exclusive $K^+\Lambda$ and $K^+\Sigma^0$ Electroproduction at 5.5 GeV with CLAS

Carman, D. S.; Park, K.; Raue, B. A.; Collaboration, CLAS
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 06/12/2012 Português
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We report measurements of the exclusive electroproduction of $K^+\Lambda$ and $K^+\Sigma^0$ final states from an unpolarized proton target using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The separated structure functions $\sigma_U$, $\sigma_{LT}$, $\sigma_{TT}$, and $\sigma_{LT'}$ were extracted from the $\Phi$-dependent differential cross sections acquired with a longitudinally polarized 5.499 GeV electron beam. The data span a broad range of momentum transfers $Q^2$ from 1.4 to 3.9 GeV$^2$, invariant energy $W$ from threshold to 2.6 GeV, and nearly the full center-of-mass angular range of the kaon. The separated structure functions provide an unprecedented data sample, which in conjunction with other meson photo- and electroproduction data, will help to constrain the higher-level analyses being performed to search for missing baryon resonances.; Comment: 27 pages, 23 figures

A common behavior of thermoelectric layered cobaltites: incommensurate spin density wave states in [Ca$_2$Co$_{4/3}$Cu$_{2/3}$O$_4$]$_{0.62}$[CoO$_2$] and [Ca$_2$CoO$_3$]$_{0.62}$[CoO$_2$]

Sugiyama, J.; Brewer, J. H.; Ansaldo, E. J.; Itahara, H.; Dohmae, K.; Xia, C.; Seno, Y.; Hitti, B.; Tani, T.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 07/11/2003 Português
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Magnetism of a misfit layered cobaltite [Ca$_2$Co$_{4/3}$Cu$_{2/3}$O$_4$]$_x^{\rm RS}$[CoO$_2$] ($x \sim$ 0.62, RS denotes a rocksalt-type block) was investigated by a positive muon spin rotation and relaxation ($\mu^+$SR) experiment. A transition to an incommensurate ({\sf IC}) spin density wave ({\sf SDW}) state was found below 180 K (= $T_{\rm C}^{\rm on}$); and a clear oscillation due to a static internal magnetic field was observed below 140 K (= $T_{\rm C}$). Furthermore, an anisotropic behavior of the zero-field $\mu^+$SR experiment indicated that the {\sf IC-SDW} propagates in the $a$-$b$ plane, with oscillating moments directed along the c axis. These results were quite similar to those for the related compound [Ca$_2$CoO$_3$]$_{0.62}^{\rm RS}$[CoO$_2$], {\sl i.e.}, Ca$_3$Co$_4$O$_9$. Since the {\sf IC-SDW} field in [Ca$_2$Co$_{4/3}$Cu$_{2/3}$O$_4$]$_{0.62}^{\rm RS}$[CoO$_2$] was approximately same to those in pure and doped [Ca$_2$CoO$_3$]$_{0.62}^{\rm RS}$[CoO$_2$], it was concluded that the {\sf IC-SDW} exist in the [CoO$_2$] planes.; Comment: 15 pages, 6 figures. accepted for publication in J. Phys.: Condens. Matter

Cabibbo-Suppressed Decays of D^+ to pi^+ pi^0, K^+ K^0, and K^+ pi^0

Arms, K.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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Using a data sample corresponding to 13.7 fb^-1 collected with the CLEO II and II.V detectors, we report new branching fraction measurements for two Cabibbo-suppressed decay modes of the D^+ meson: Br(D^+ to pi^+ pi^0) = (1.3 +/- 0.2) x 10^-3 and Br(D^+ to \bar{K}^0 K^+) = (5.2 +/- 0.6) x 10^-3 which are significant improvements over past measurements. The errors include statistical and systematical uncertainties as well as the uncertainty in the absolute D^+ branching fraction scale. We also set the first 90% confidence level upper limit on the branching fraction of the doubly Cabibbo-suppressed decay mode Br(D^+ to K^+ pi^0) < 4.2 x 10^-4.; Comment: 8 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS,Submitted as EPS-371, Aachen, Germany. Several Corrections made that did not change branching fractions but did effect interpretation

The decay $\tau \rightarrow K^{-}\pi^{0}\nu_{\tau}$ in the Nambu--Jona-Lasinio model

Volkov, M. K.; Pivovarov, A. A.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
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56.672197%
In the present paper, the width of the decay $\tau \rightarrow K^{-}\pi^{0}\nu_{\tau}$ is obtained in the framework of the Nambu--Jona-Lasinio model. The contributions of the intermediate vector $K^{*}(892)$ and scalar $K_{0}^{*}(800)$ mesons are taken into account. It is shown that the main contribution to the width of this decay is given by the subprocesses with the intermediate $W$-boson and vector $K^{*}(892)$ meson. The scalar channel with the intermediate $K_{0}^{*}(800)$ meson gives an insignificant contribution. In Appendix, it is shown that the contribution of the subprocess with the intermediate ${K^{*}}'(1410)$ meson is negligible.; Comment: 7 pages, 4 figures

Synthesis, Structural, Electrical and Microchemistry Properties of Novel (LSCFM) LaxSr1-xCo1-y-zFeyMnzO3-{\delta} (x=0.4, 0.6, 0.8, y=0.4, 0.8 and z=0.1, 0.2) Perovskites for SOFC Applications

Tsiligkeridis, E. A.; Makridis, S. S.; Pavlidou, E.; Kikkinides, E. S.; Stubos, A. K.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 30/07/2011 Português
Relevância na Pesquisa
56.705015%
Perovskites are mixed oxides with the general formula ABO3. Many different compositions have been found to be possible and their number is growing rapidly due to their characteristics that make them ideal for various applications, such as fabrication of cathodes for solid oxide fuel cells (SOFCs). Oxide powders of LaxSr1-xCo1-y-zFeyMnzO3-{\delta} (x=0.4, 0.6, 0.8, y=0.4, 0.8 and z=0.1, 0.2), named LSCFM, were prepared by mixing commercial powders. The powders have been investigated as a function of the stoichiometry and the crystal structure parameters have been determined using Rietveld analysis. The results of the structural analysis for each sintered sample, at low temperature sintering (1100 {\omicron}C), have been obtained by considering two cubic perovskite phases, for x=0.4 or one cubic and one orthorhombic phase for x=0.6, 0.8, respectively. Analysis of microstructure has shown a maximum grain size of ~0.63 {\mu}m. The annealed sample at 1100 {\omicron}C, an almost single phase specimen, exhibited an electrical conductivity of 1.29\times103 ({\Omega} \cdot cm)-1. The sintered sample at 1250 {\omicron}C has higher conductivity but sharper curve close to the maximum. We suggest that low temperature sintering reveal two phase system with broader curve maximum and high conductivity for future applications in SOFCs.; Comment: 7 figures...

Spin alignment of leading K*(892)^0 mesons in hadronic Z^0 decays

The OPAL Collaboration; al, K. Ackerstaff et
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 16/08/1997 Português
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Helicity density matrix elements for inclusive K*(892)^0 mesons from hadronic Z^0 decays have been measured over the full range of K^*0 momentum using data taken with the OPAL experiment at LEP. A preference for occupation of the helicity zero state is observed at all scaled momentum x_p values above 0.3, with the matrix element rho_00 rising to 0.66 +/- 0.11 for x_p > 0.7. The values of the real part of the off-diagonal element rho_1-1 are negative at large x_p, with a weighted average value of -0.09 +/- 0.03 for x_p > 0.3, in agreement with new theoretical predictions based on Standard Model parameters and coherent fragmentation of the qq(bar) system from the Z^0 decay. All other helicity density matrix elements measured are consistent with zero over the entire x_p range. The K^*0 fragmentation function has also been measured and the total rate determined to be 0.74 +/- 0.02 +/- 0.02 K*(892)^0 mesons per hadronic Z^0 decay.; Comment: 19 pages, LaTeX, uses a4p.sty, pennames.sty, 4 eps figures included, submitted to Phys. Lett. B

First model-independent Dalitz analysis of $B^0 \to DK^{*0}$, $D\to K_S^0\pi^+\pi^-$ decay

Belle Collaboration; Negishi, K.; Ishikawa, A.; Yamamoto, H.; Abdesselam, A.; Adachi, I.; Aihara, H.; Said, S. Al; Asner, D. M.; Aulchenko, V.; Aushev, T.; Ayad, R.; Babu, V.; Badhrees, I.; Bahinipati, S.; Bakich, A. M.; Barberio, E.; Biswal, J.; Bonvicin
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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We report a measurement of the amplitude ratio $r_S$ of $B^0 \to D^0K^{*0}$ and $B^0 \to \bar{D^0}K^{*0}$ decays with a Dalitz analysis of $D\to K_S^0\pi^+\pi^-$ decays, for the first time using a model-independent method. We set an upper limit $r_S < 0.87$ at the 68\% confidence level, using the full data sample of $772\times10^6$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB $e^+e^-$ collider. This result is obtained from observables $x_- = +0.4 ^{+1.0 +0.0}_{-0.6 -0.1} \pm0.0$, $y_- = -0.6 ^{+0.8 +0.1}_{-1.0 -0.0} \pm0.1$, $x_+ = +0.1 ^{+0.7 +0.0}_{-0.4 -0.1} \pm0.1$ and $y_+ = +0.3 ^{+0.5 +0.0}_{-0.8 -0.1} \pm0.1$, where $x_\pm = r_S \cos(\delta_S \pm \phi_3)$, $y_\pm = r_S \sin(\delta_S \pm \phi_3)$ and $\phi_3~(\delta_S)$ is the weak (strong) phase difference between $B^0 \to D^0K^{*0}$ and $B^0 \to \bar{D^0}K^{*0}$.; Comment: arXiv admin note: substantial text overlap with arXiv:1502.07550

Measurement of ${D^{0}}$-${\overline{D}{}^{0}}$ Mixing and Search for Indirect $CP$ Violation Using ${D^0\to K_S^0\pi^+\pi^-}$ Decays

Belle Collaboration; Abdesselam, A.; Adachi, I.; Aihara, H.; Arinstein, K.; Asner, D. M.; Aulchenko, V.; Aushev, T.; Ayad, R.; Bakich, A. M.; Bala, A.; Bhardwaj, V.; Bhuyan, B.; Bobrov, A.; Bondar, A.; Bonvicini, G.; Bozek, A.; Červenkov, D.; Chekelian,
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/04/2014 Português
Relevância na Pesquisa
56.68268%
We report a measurement of ${D^{0}}$-${\overline{D}{}^{0}}$ mixing parameters and a search for indirect $CP$ violation through a time-dependent amplitude analysis of ${D^0\to K_S^0\pi^+\pi^-}$ decays. The results are based on 921~fb$^{-1}$ of data accumulated with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. Assuming $CP$ conservation, we measure the mixing parameters $x=(0.56\pm0.19^{+0.03}_{-0.09}{^{+0.06}_{-0.09}})\%$ and $y=(0.30\pm0.15^{+0.04}_{-0.05}{^{+0.03}_{-0.06})}\%$, where the errors are statistical, experimental systematic, and systematic due to the amplitude model, respectively. With $CP$ violation allowed, the parameters $|q/p|=0.90^{+0.16}_{-0.15}{^{+0.05}_{-0.04}}{^{+0.06}_{-0.05}}$ and $\arg(q/p)=(-6\pm11{\pm3}{^{+3}_{-4}})^{\circ}$ are found to be consistent with conservation of $CP$ symmetry in mixing and in the interference between mixing and decay, respectively.; Comment: submitted to PRD(RC)

Measurement of the amplitude ratio of $B^0 \to D^0K^{*0}$ and $B^0 \to \bar{D^0}K^{*0}$ decays with a model-independent Dalitz plot analysis using $D\to K_S^0\pi^+\pi^-$ decays

Abdesselam, A.; Adachi, I.; Adamczyk, K.; Aihara, H.; Said, S. Al; Arinstein, K.; Arita, Y.; Asner, D. M.; Aso, T.; Aulchenko, V.; Aushev, T.; Ayad, R.; Aziz, T.; Babu, V.; Badhrees, I.; Bahinipati, S.; Bakich, A. M.; Bala, A.; Ban, Y.; Bansal, V.; Barber
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
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We report a measurement of the amplitude ratio $r_S$ of $B^0 \to D^0K^{*0}$ and $B^0 \to \bar{D^0}K^{*0}$ decays with a model-independent Dalitz plot analysis using $D\to K_S^0\pi^+\pi^-$ decays. Using the full data sample of $772\times10^6$ $B\bar{B}$ pairs collected at the $\Upsilon(4S)$ resonance with the Belle detector at KEKB accelerator the upper limit is $r_S < 0.87$ at the 68 % confidence level. This result is the first measurement of $r_S$ with a model-independent Dalitz analysis, and is consistent with results from other analyses. The value of $r_S$ indicates the sensitivity of the decay to $\phi_3$ because the statistical uncertainty is proportional to $1/r_S$. The $r_S$ result is obtained from observables ($x_\pm$, $y_\pm$) \begin{eqnarray} x_- &=& +0.4 ^{+1.0 +0.0}_{-0.6 -0.1} \pm0.0 \\ y_- &=& -0.6 ^{+0.8 +0.1}_{-1.0 -0.0} \pm0.1 \\ x_+ &=& +0.1 ^{+0.7 +0.0}_{-0.4 -0.1} \pm0.1 \\ y_+ &=& +0.3 ^{+0.5 +0.0}_{-0.8 -0.1} \pm0.1 \\ , \end{eqnarray} where $x_\pm = r_S \cos(\delta_S \pm \phi_3)$, $y_\pm = r_S \sin(\delta_S \pm \phi_3)$ and $\phi_3 (\delta_S)$ are the weak (strong) phase difference between $B^0 \to D^0K^{*0}$ and $B^0 \to \bar{D^0}K^{*0}$. The first uncertainty is statistical, the second is the experimental systematic and the third is the systematic due to the uncertainties on $c_i$ and $s_i$ parameters measured by CLEO.

Search for the decay $K_L^0 \rightarrow 3\gamma$

Tung, Y. C.; Hsiung, Y. B.; Ahn, J. K.; Akune, Y.; Baranov, V.; Chen, K. F.; Comfort, J.; Doroshenko, M.; Fujioka, Y.; Inagaki, T.; Ishibashi, S.; Ishihara, N.; Ishii, H.; Iwai, E.; Iwata, T.; Kato, I.; Kobayashi, S.; Komatsu, S.; Komatsubara, T. K.; Kuri
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
56.65862%
We performed a search for the decay $K_L^0 \rightarrow 3\gamma$ with the E391a detector at KEK. In the data accumulated in 2005, no event was observed in the signal region. Based on the assumption of $K_L^0 \rightarrow 3\gamma$ proceeding via parity-violation, we obtained the single event sensitivity to be $(3.23\pm0.14)\times10^{-8}$, and set an upper limit on the branching ratio to be $7.4\times10^{-8}$ at the 90% confidence level. This is a factor of 3.2 improvement compared to the previous results. The results of $K_L^0 \rightarrow 3\gamma$ proceeding via parity-conservation were also presented in this paper.

Measurement of $K^*(892)^0$ and $K^0$ mesons in Al+Al collisions at 1.9$A$ GeV

Lopez, X.; Herrmann, N.; Piasecki, K.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 09/06/2010 Português
Relevância na Pesquisa
56.77869%
New measurement of sub-threshold $K^*(892)^0$ and $K^0$ production is presented. The experimental data complete the measurement of strange particles produced in Al+Al collisions at 1.9$A$ GeV measured with the FOPI detector at SIS/GSI. The $K^*(892)^0$ / $K^0$ yield ratio is found to be $0.0315\pm 0.006 (\mathrm{stat.})\pm 0.012 (\mathrm{syst.})$ and is in good agreement with the UrQMD model prediction. These measurements provide information on in-medium cross section of $K^+$ - $\pi^-$ fusion which is the dominant process on sub-threshold $K^*(892)^0$ production.; Comment: 5 pages, 4 figures, accepted for publication in Phys. Rev. C

Multiquantum well structure with an average electron mobility of 4.0×10^6 cm^2/V s

Pfeiffer, L. N.; West, K. W.; Eisenstein, J. P.; Baldwin, K. W.; Gammel, P.
Fonte: American Institute of Physics Publicador: American Institute of Physics
Tipo: Article; PeerReviewed Formato: application/pdf
Publicado em 07/09/1992 Português
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We report a modulation-doped multiquantum well structure which suppresses the usual ambient light effect associated with modulation doping. Ten GaAs quantum wells 300-Å wide are symmetrically modulation doped using Si δ doping at the center of 3600-Å-wide Al0.1Ga0.9As barriers. The low field mobility of each well is 4.0×10^6 cm/V s at a density of 6.4×10^10 cm^−2 measured at 0.3 K either in the dark, or during, or after, exposure to light. This mobility is an order of magnitude improvement over previous work on multiwells.