6,190 research outputs found
Drug repurposing against COVID-19. focus on anticancer agents
The very limited time allowed to face the COVID-19 pandemic poses a pressing challenge to find proper therapeutic approaches. However, synthesis and full investigation from preclinical studies to phase III trials of new medications is a time-consuming procedure, and not viable in a global emergency, such as the one we are facing
Isotropic properties of the photonic band gap in quasicrystals with low-index contrast
We report on the formation and development of the photonic band gap in
two-dimensional 8-, 10- and 12-fold symmetry quasicrystalline lattices of low
index contrast. Finite size structures made of dielectric cylindrical rods were
studied and measured in the microwave region, and their properties compared
with a conventional hexagonal crystal. Band gap characteristics were
investigated by changing the direction of propagation of the incident beam
inside the crystal. Various angles of incidence from 0 \degree to 30\degree
were used in order to investigate the isotropic nature of the band gap. The
arbitrarily high rotational symmetry of aperiodically ordered structures could
be practically exploited to manufacture isotropic band gap materials, which are
perfectly suitable for hosting waveguides or cavities.Comment: 16 pages, 7 figures, submitted to PR
Cosmogenic neutrino fluxes under the effect of active-sterile secret interactions
Ultra High Energy cosmogenic neutrinos may represent a unique opportunity to
unveil possible new physics interactions once restricted to the neutrino sector
only. In the present paper we study the observable effects of a secret
active-sterile interactions, mediated by a pseudoscalar, on the expected flux
of cosmogenic neutrinos. The results show that for masses of sterile neutrinos
and pseudoscalars of hundreds MeV, necessary to evade cosmological,
astrophysical and elementary particle constraints, the presence of such new
interactions can significantly change the energy spectrum of cosmogenic
neutrinos at Earth in the energy range from PeV to ZeV. Interestingly, the
distortion of the spectrum results to be detectable at GRAND apparatus if the
scalar mediator mass is around 250 MeV and the UHECRs are dominated by the
proton component. Larger mediator masses or a chemical composition of UHECRs
dominated by heavier nuclei would require much larger cosmic rays apparatus
which might be available in future.Comment: 10 pages, 3 figure
Response of House Foundations During the Loma Prieta Earthquake
Significant damage to house foundations has resulted from the Lorna Prieta earthquake. In some cases the cost to repair the foundation and to make the necessary seismic upgrades exceeded the market value of the house. This level of foundation damage was found at various distances from the epicenter and in different geologic settings. Presented in this paper are observations made on the foundation responses to various ground effects from the earthquake shaking. Also pointed out is the difference in performance of various affected foundation systems
Structural change in multipartite entanglement sharing: a random matrix approach
We study the typical entanglement properties of a system comprising two
independent qubit environments interacting via a shuttling ancilla. The initial
preparation of the environments is modeled using random-matrix techniques. The
entanglement measure used in our study is then averaged over many histories of
randomly prepared environmental states. Under a Heisenberg interaction model,
the average entanglement between the ancilla and one of the environments
remains constant, regardless of the preparation of the latter and the details
of the interaction. We also show that, upon suitable kinematic and dynamical
changes in the ancilla-environment subsystems, the entanglement-sharing
structure undergoes abrupt modifications associated with a change in the
multipartite entanglement class of the overall system's state. These results
are invariant with respect to the randomized initial state of the environments.Comment: 10 pages, RevTeX4 (Minor typo's corrected. Closer to published
version
Microwave Harmonic Emission in MgB2 Superconductor: Comparison with YBaCuO
We report results of microwave second-harmonic generation in ceramic samples
of MgB2, prepared by different methods. The SH signal has been investigated as
a function of the temperature and the static magnetic field. The results are
discussed in the framework of models reported in the literature. We show that
the peculiarities of the SH signal are related to the specific properties of
the sample. A comparison with the results obtained in ceramic and crystalline
YBa(2)Cu(3)O(7) shows that the second-harmonic emission in MgB2 is weaker than
that observed in ceramic YBa(2)Cu(3)O(7).Comment: 13 pages, 6 figures; Proceedings of Third Workshop on Metamaterials
and Special Materials for Electromagnetic Applications and TLC (Rome, 30-31
March, 2006
Twenty-first semiannual report to Congress, 1 January - 30 June 1969
Manned space flights, satellite observations, space sciences, and air traffic control - NASA report to Congress for 1 Jan. to 30 June 196
Relaxation due to random collisions with a many-qudit environment
We analyze the dynamics of a system qudit of dimension mu sequentially
interacting with the nu-dimensional qudits of a chain playing the ore of an
environment. Each pairwise collision has been modeled as a random unitary
transformation. The relaxation to equilibrium of the purity of the system
qudit, averaged over random collisions, is analytically computed by means of a
Markov chain approach. In particular, we show that the steady state is the one
corresponding to the steady state for random collisions with a single
environment qudit of effective dimension nu_e=nu*mu. Finally, we numerically
investigate aspects of the entanglement dynamics for qubits (mu=nu=2) and show
that random unitary collisions can create multipartite entanglement between the
system qudit and the qudits of the chain.Comment: 7 pages, 6 figure
The out of plane behaviour of masonry infilled frames
The great interest about out of plane behavior of masonry infill walls has recently increased since it is a key point in the seismic modelling of framed structures. Their contribute to the whole seismic resistance of a framed building cannot be skipped. After a review of the literature on the subject, this paper presents a trilinear constitutive model for the out of plane behavior of masonry infills based on the tensile strength of the constituents. Comparisons with literature model are provided and the identification of the model is based on experimental tests
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