446 research outputs found
Review of \u3cem\u3eMafias on the Move: How Organized Crime Conquers New Territories,\u3c/em\u3e by Federico Varese
An âUntrammeled Rightâ? The McCarran Immigration Subcommittee and the Origins of Presidential Authority to Suspend and Restrict Alien Entry Under §1182(f)
The language of Section 212(e) of the 1952 Immigration and Nationality Act, 8 U.S.C. §1182(f), contains a sweeping authorization of presidential discretion to suspend and restrict alien entry into the United States. Senator Pat McCarran (D-NV) first introduced the subsection in 1950 as part of the omnibus immigration bill drafted by his Judiciary Committeeâs immigration subcommittee. The specific origins of the language and the original intent behind the subsection remain missing pieces in the extensive scholarly literature on the 1952 INA and legislative history as explored by the courts. This article reveals that the subcommittee modeled the subsection on the sixth proviso of the 1917 Immigration Act, the May 1918 Wartime Measure, and a selective interpretation of Supreme Court precedent. The article reveals further that the original intent behind the subsection was to close perceived loopholes in existing law enabling entry by displaced persons and Communist governmental officials
Many-Body Corrections to Charged-Current Neutrino Absorption Rates in Nuclear Matter
Including nucleon--nucleon correlations due to both Fermi statistics and
nuclear forces, we have developed a general formalism for calculating the
charged--current neutrino--nucleon absorption rates in nuclear matter. We find
that at one half nuclear density many--body effects alone suppress the rates by
a factor of two and that the suppression factors increase to 5 at
g cm. The associated increase in the neutrino--matter
mean--free--paths parallels that found for neutral--current interactions and
opens up interesting possibilities in the context of the delayed supernova
mechanism and protoneutron star cooling.Comment: 11 pages, APS REVTeX format, 1 PostScript figure, uuencoded
compressed, and tarred, submitted to Physical Review Letter
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Fresh perspectives on customer experience
Purpose
â The purpose of this paper is to provide directions for future research on: broadening the role of customers in customer experience; taking a practice-based approach to customer experience; and recognizing the holistic, dynamic nature of customer experience across all touch points and over time.
Design/methodology/approach
â The approach is conceptual identifying current gaps in research on customer experience.
Findings
â The findings include a set of research questions and research agenda for future research on customer experience.
Originality/value
â This research suggests fresh perspectives for understanding the customer experience which can inspire future research and advance theory and managerial practice
Modern nucleon-nucleon potentials and symmetry energy in infinite matter
We study the symmetry energy in infinite nuclear matter employing a
non-relativistic Brueckner-Hartree-Fock approach and using various new
nucleon-nucleon (NN) potentials, which fit np and pp scattering data very
accurately. The potential models we employ are the recent versions of the
Nijmegen group, Nijm-I, Nijm-II and Reid93, the Argonne potential and
the CD-Bonn potential. All these potentials yield a symmetry energy which
increases with density, resolving a discrepancy that existed for older NN
potentials. The origin of remaining differences is discussed.Comment: 17 pages, 10 figures included, elsevier latex style epsart.st
Transport coefficients of O(N) scalar field theories close to the critical point
We investigate the critical dynamics of O(N)-symmetric scalar field theories
to determine the critical exponents of transport coefficients as a second-order
phase transition is approached from the symmetric phase. A set of stochastic
equations of motion for the slow modes is formulated, and the long wavelength
dynamics is examined for an arbitrary number of field components, , in the
framework of the dynamical renormalization group within the
expansion. We find that for a single component scalar field theory, N=1, the
system reduces to the model C of critical dynamics, whereas for the model
G is effectively restored owing to dominance of O(N)-symmetric charge
fluctuations. In both cases, the shear viscosity remains finite in the critical
region. On the other hand, we find that the bulk viscosity diverges as the
correlation length squared, for N=1, while it remains finite for .Comment: revised for publication in PR
Vector Meson Photoproduction with an Effective Lagrangian in the Quark Model
A quark model approach to the photoproduction of vector mesons off nucleons
is proposed. Its starting point is an effective Lagrangian of the interaction
between the vector meson and the quarks inside the baryon, which generates the
non-diffractive s- and u- channel resonance contributions. Additional t-channel
and exchanges are included for the and
production respectively to account for the large diffractive behavior in the
small region as suggested by Friman and Soyeur. The numerical results are
presented for the and productions in four isospin channels with
the same set of parameters, and they are in good agreement with the available
data not only in and productions but also in the charged
productions where the additional t-channel exchange does not
contribute so that it provides an important test to this approach. The
investigation is also extended to the photoproduction, and the initial
results show that the non-diffractive behavior of the productions in the
large region can be described by the s- and u- channel contributions with
significantly smaller coupling constants, which is consistent with the findings
in the similar studies in the QHD framework. The numerical investigation has
also shown that polarization observables are essential for identifying
so-called "missing resonances".Comment: 36 pages, 10 PS figures, extended version of nucl-th/9711061 and
nucl-th/9803021, submitted to PR
Study of possible \omega bound states in nuclei with the (\gamma,p) reaction
We perform calculations for \omega production in nuclei by means of the
(\gamma,p) reaction for photon energies and proton angles suited to running and
future experiments in present Laboratories. For some cases of possible \omega
optical potentials we find clear peaks which could be observable provided a
good resolution in the \omega energy is available. We also study the inclusive
production of \pi^0 \gamma in nuclei around the \omega energy and find a double
hump structure for the energy spectra, with a peak around a \pi^0 \gamma energy
of m_{\omega}-100 MeV, which could easily be misidentified by a signal of a
bound \omega state in nuclei, while it is due to a different scaling of the
uncorrelated \pi^0 \gamma production and \omega production with subsequent
\pi^0 \gamma decay.Comment: 19 pages, 10 figure
Meson - nucleon vertex form factors at finite temperature
In this paper the dependence of meson-nucleon-nucleon vertex form factors is
studied as a function of termperature. The results are obtained starting from a
zero temperature Bonn potential. The temperature dependence of the vertex form
factors and radii is studied in the thermofield dynamics, a real-time operator
formalism of finite temperature field theory. It is anticipated that these
results will have an impact on the study of relativistic heavy-ion collisions
as the critical temperature for the phase transition from hadronic to
quark-gluon system is approached.Comment: 19 pages, Revtex, 11 figures (Ps), 171k
An isotopic effect in phi photoproduction at a few GeV
A distinct isotopic effect in phi photoproduction at 2-5 GeV region is
identified by examining the production amplitudes due to Pomeron-exchange and
meson-exchange mechanisms. This effect is mainly caused by the pi-eta
interference constrained by SU(3) symmetry and the isotopic structure of the
gamma NN coupling in the direct phi-radiation amplitude. It can be tested
experimentally by measuring differences in the polarization observables between
the gamma-p and gamma-n reactions.Comment: 11 pages, 6 figure
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