82,577 research outputs found
An econometric analysis of SARS and Avian flu on international tourist arrivals to Asia
This paper compares the impacts of SARS and human deaths arising from Avian Flu on international tourist arrivals to Asia. The effects of SARS and human deaths from Avian Flu will be compared directly according to human deaths. The nature of the short run and long run relationship is examined empirically by estimating a static line fixed effect model and a difference transformation dynamic model, respectively. Empirical results from the static fixed effect and difference transformation dynamic models are consistent, and indicate that both the short run and long run SARS effect have a more significant impact on international tourist arrivals than does Avian Flu. In addition, the effects of deaths arising from both SARS and Avian Flu suggest that SARS is more important to international tourist arrivals than is Avian Flu. Thus, while Avian Flu is here to stay, its effect is currently not as significant as that of SARS.Avian flu;international tourism;SARS;dynamic panel data model;static fixed effects model
Binding-incompetent adenovirus facilitates molecular conjugate-mediated gene transfer by the receptor-mediated endocytosis pathway
Molecular conjugate vectors may be constructed that accomplish high efficiency gene transfer by the receptor-mediated endocytosis pathway. In order to mediate escape from lysosomal degradation, we have incorporated adenoviruses into the functional design of the conjugate. In doing so, however, we have introduced an additional ligand, which can bind to receptors on the cell surface, undermining the potential for cell specific targeting. To overcome this, we have treated the adenovirus with a monoclonal anti-fiber antibody, which renders the virus incapable of binding to its receptor. The result is a multi-functional molecular conjugate vector, which has preserved its binding specificity while at the same time being capable of preventing lysosomal degradation of endosome-internalized conjugate-DNA complexes. This finding indicates that adenoviral binding is not a prerequisite for adenoviral-mediated endosome disruption
Periodic Modulation of Extraordinary Optical Transmission through Subwavelength Hole Arrays using Surrounding Bragg Mirrors
The enhanced light transmission through an array of subwavelength holes
surrounded by Bragg mirrors is studied, showing that the mirrors act to confine
the surface plasmons associated with the Extraordinary Optical Transmission
effect, forming a surface resonant cavity. The overall effect is increased
light transmission intensity by more than a factor of three beyond the already
enhanced transmission, independent of whether the Bragg mirrors are on the
input or the output side of the incident light. The geometry of the Bragg
mirror structures controls the enhancement, and can even reduce the
transmission in half. By varying these geometric parameters, we were able to
periodically modulate the transmission of light for specific wavelengths,
consistent with the propagation and interference of surface plasmon waves in a
resonant cavity. FDTD simulations and a wave propagation model verify this
effect.Comment: 9 pages, 5 figure
New nonlinear dielectric materials: Linear electrorheological fluids under the influence of electrostriction
The usual approach to the development of new nonlinear dielectric materials
focuses on the search for materials in which the components possess an
inherently large nonlinear dielectric response. In contrast, based on
thermodynamics, we have presented a first-principles approach to obtain the
electrostriction-induced effective third-order nonlinear susceptibility for the
electrorheological (ER) fluids in which the components have inherent linear,
rather than nonlinear, responses. In detail, this kind of nonlinear
susceptibility is in general of about the same order of magnitude as the
compressibility of the linear ER fluid at constant pressure. Moreover, our
approach has been demonstrated in excellent agreement with a different
statistical method. Thus, such linear ER fluids can serve as a new nonlinear
dielectric material.Comment: 11 page
Effect of humidity on transonic flow
An experimental investigation of the effects of humidity-induced condensation on shock/boundary-layer
interaction has been conducted in a transonic wind-tunnel test. The test geometry considered was a wall-mounted
bump model inserted in the test section of the wind tunnel. The formation of a λ-shape condensation shock wave was
shown from schlieren visualization and resulted in a forward movement of the shock wave, reduced shock wave
strength, and reduced separation. Empirical correlations of the shock wave strength and humidity/dew point
temperature were established. For humidity levels below 0.15 or a dew point temperature of 268 K, the effect of
humidity was negligible. The unsteady pressure measurements showed that if a condensation shock wave formed and
interacted with a main shock wave, the flow becomes unsteady with periodic flow oscillations occurring at 720 Hz
Z-graded weak modules and regularity
It is proved that if any Z-graded weak module for vertex operator algebra V
is completely reducible, then V is rational and C_2-cofinite. That is, V is
regular. This gives a natural characterization of regular vertex operator
algebras.Comment: 9 page
Hydrodynamics of superfluids confined in blocked rings and wedges
Motivated by many recent experimental studies of non-classical rotational
inertia (NCRI) in superfluid and supersolid samples, we present a study of the
hydrodynamics of a superfluid confined in the two-dimensional region
(equivalent to a long cylinder) between two concentric arcs of radii and
() subtending an angle , with . The case
corresponds to a blocked ring. We discuss the methodology to
compute the NCRI effects, and calculate these effects both for small angular
velocities, when no vortices are present, and in the presence of a vortex. We
find that, for a blocked ring, the NCRI effect is small, and that therefore
there will be a large discontinuity in the moment of inertia associated with
blocking or unblocking circular paths. For blocked wedges () with , we find an unexpected divergence of the velocity at the origin, which
implies the presence of either a region of normal fluid or a vortex for {\it
any} nonzero value of the angular velocity. Implications of our results for
experiments on "supersolid" behavior in solid are discussed. A
number of mathematical issues are pointed out and resolved.Comment: 15 pages, including figures. To appear in Phys. Rev.
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