The Synthesis, Resolution and Configuration of Beta-hydroxyvaline

Synthesis, resolution, and configuration of alpha-hydroxyvalin

Optical Resolution and Configuration of Trans-2,3-epoxybutyric Acid

Optical resolution of epoxy derivative of butyric acid with brucine and configuration determination by treatment with ammoni

Betweenness centrality correlation in social networks

Scale-free (SF) networks exhibiting a power-law degree distribution can be grouped into the assortative, dissortative and neutral networks according to the behavior of the degree-degree correlation coefficient. Here we investigate the betweenness centrality (BC) correlation for each type of SF networks. While the BC-BC correlation coefficients behave similarly to the degree-degree correlation coefficients for the dissortative and neutral networks, the BC correlation is nontrivial for the assortative ones found mainly in social networks. The mean BC of neighbors of a vertex with BC $g_i$ is almost independent of $g_i$, implying that each person is surrounded by almost the same influential environments of people no matter how influential the person is.Comment: 4 pages, 4 figures, 1 tabl

Higher and missing resonances in omega photoproduction

We study the role of the nucleon resonances ($N^*$) in $\omega$ photoproduction by using the quark model resonance parameters predicted by Capstick and Roberts. The employed $\gamma N \to N^*$ and $N^* \to \omega N$ amplitudes include the configuration mixing effects due to the residual quark-quark interactions. The contributions from the nucleon resonances are found to be important in the differential cross sections at large scattering angles and various spin observables. In particular, the parity asymmetry and beam-target double asymmetry at forward scattering angles are suggested for a crucial test of our predictions. The dominant contributions are found to be from $N\frac32^+ (1910)$, a missing resonance, and $N\frac32^- (1960)$ which is identified as the $D_{13}(2080)$ of the Particle Data Group.Comment: 8 pages, LaTeX with ws-p8-50x6-00.cls, 4 figures (5 eps files), Talk presented at the NSTAR2001 Workshop on the Physics of Excited Nucleons, Mainz, Germany, Mar. 7-10, 200

Electromagnetic production of vector mesons at low energies

We have investigated exclusive photoproduction of light vector mesons ($\omega$, $\rho$ and $\phi$) on the nucleon at low energies. In order to explore the questions concerning the so-called missing nucleon resonances, we first establish the predictions from a model based on the Pomeron and meson exchange mechanisms. We have also explored the contributions due to the mechanisms involving $s$- and $u$-channel intermediate nucleon state. Some discrepancies found at the energies near threshold and large scattering angles suggest a possibility of using this reaction to identify the nucleon resonances.Comment: 9 pages, LaTeX with sprocl.sty, 5 figures (11 eps files), Talk presented at the NSTAR2000 Workshop, The Physics of Excited Nucleons, Jefferson Lab., Newport News, Feb. 16-19, 200

Probing nucleon strangeness in phi electroproduction

We investigate $\phi$ meson electroproduction to probe the hidden strangeness content of the nucleon. We found that even a small amount of the $s\bar{s}$ admixture in the nucleon wavefunction can lead to a significant change in several double polarization asymmetries in $\phi$ electroproduction, which can be tested experimentally at current electron facilities.Comment: 3 pages, 1 figure (2 eps files), LaTeX2e with espcrc1.sty, Talk at the XVI International Conference on Few-Body Problems in Physics (FB16), Taipei, Taiwan, March 6-10, 200