10,087 research outputs found
The high-energy galactic tau neutrino flux and its atmospheric background
We compare the tau neutrino flux arising from the galaxy and the earth
atmosphere for . The intrinsic and oscillated
tau neutrino fluxes from both sources are considered. We find that, for GeV, the oscillated flux along the galactic plane dominates
over the maximal intrinsic atmospheric flux, i.e., the flux along
the horizontal direction. We also briefly comment on the prospects for
observing these high-energy tau neutrinos.Comment: 3 pages, 2 figures, talk presented in EPS03, Aachen, German
Applications of Transmission Electron Microscopy to Coal
Coal consists of a hydrocarbon matrix in which minerals are embedded. The hydrocarbon matter also contains impurities distributed as individual atoms. Thus, coal has phases similar to those in metallic or ceramic alloy systems; a matrix, included precipitates and atoms distributed individually in solid solution. Consequently, techniques of electron microscopy developed to examine metallic and ceramic alloy systems are directly applicable to coal. We report application of microanalytical techniques of electron microscopy to coal using examples of measurements for several coals. Identification and characterization of clays and sulfides is described. Use of x-ray emission spectroscopy for organic element measurement is emphasized
Inhibition of dengue virus replication by novel inhibitors of RNA-dependent RNA polymerase and protease activities
Dengue virus (DENV) is the leading mosquito-transmitted viral infection in the world. With more than 390 million new infections annually, and up to 1 million clinical cases with severe disease manifestations, there continues to be a need to develop new antiviral agents against dengue infection. In addition, there is no approved anti-DENV agents for treating DENV-infected patients. In the present study, we identified new compounds with anti-DENV replication activity by targeting viral replication enzymes – NS5, RNA-dependent RNA polymerase (RdRp) and NS3 protease, using cell-based reporter assay. Subsequently, we performed an enzyme-based assay to clarify the action of these compounds against DENV RdRp or NS3 protease activity. Moreover, these compounds exhibited anti-DENV activity in vivo in the ICR-suckling DENV-infected mouse model. Combination drug treatment exhibited a synergistic inhibition of DENV replication. These results describe novel prototypical small anti-DENV molecules for further development through compound modification and provide potential antivirals for treating DENV infection and DENV-related diseases
Lagrangian Floer superpotentials and crepant resolutions for toric orbifolds
We investigate the relationship between the Lagrangian Floer superpotentials
for a toric orbifold and its toric crepant resolutions. More specifically, we
study an open string version of the crepant resolution conjecture (CRC) which
states that the Lagrangian Floer superpotential of a Gorenstein toric orbifold
and that of its toric crepant resolution coincide after
analytic continuation of quantum parameters and a change of variables. Relating
this conjecture with the closed CRC, we find that the change of variable
formula which appears in closed CRC can be explained by relations between open
(orbifold) Gromov-Witten invariants. We also discover a geometric explanation
(in terms of virtual counting of stable orbi-discs) for the specialization of
quantum parameters to roots of unity which appears in Y. Ruan's original CRC
["The cohomology ring of crepant resolutions of orbifolds", Gromov-Witten
theory of spin curves and orbifolds, 117-126, Contemp. Math., 403, Amer. Math.
Soc., Providence, RI, 2006]. We prove the open CRC for the weighted projective
spaces using an equality between open
and closed orbifold Gromov-Witten invariants. Along the way, we also prove an
open mirror theorem for these toric orbifolds.Comment: 48 pages, 1 figure; v2: references added and updated, final version,
to appear in CM
Scalar-Torsion Mode in a Cosmological Model of the Poincar\'{e} Gauge Theory of Gravity
We investigate the equation of state (EoS) of the scalar-torsion mode in
Poincar\'{e} gauge theory of gravity. We concentrate on two cases with the
constant curvature solution and positive kinetic energy, respectively. In the
former, we find that the torsion EoS has different values in the various stages
of the universe. In particular, it behaves like the radiation (matter) EoS of
() in the radiation (matter) dominant epoch, while in the late
time the torsion density is supportive for the accelerating universe. In the
latter, our numerical analysis shows that in general the EoS has an asymptotic
behavior in the high redshift regime, while it could cross the phantom divide
line in the low redshift regime.Comment: 12 pages, 2 figures, title changed, revised version accepted for
publication in JCA
Gamma-ray Constraints on Effective Interactions of the Dark Matter
Using an effective interaction approach to describe the interactions between
the dark matter particle and the light degrees of freedom of the standard
model, we calculate the gamma-ray flux due to the annihilation of the dark
matter into quarks, followed by fragmentation into neutral pions which
subsequently decay into photons. By comparison to the mid-latitude data
released from the Fermi-LAT experiment, we obtain useful constraints on the
size of the effective interactions and they are found to be comparable to those
deduced from collider, gamma-ray line and anti-matter search experiments.
However, the two operators induced by scalar and vector exchange among
fermionic dark matter and light quarks that contribute to spin-independent
cross sections are constrained more stringently by the recent XENON100 data.Comment: 22 pages, 4 figures; title fixed and a couple of references adde
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