3,407 research outputs found
Spatial expansions and travelling waves of rabies in vampire bats
A major obstacle to anticipating the cross-species transmission of zoonotic diseases and developing novel strategies for their control is the scarcity of data informing how these pathogens circulate within natural reservoir populations. Vampire bats are the primary reservoir of rabies in Latin America, where the disease remains among the most important viral zoonoses affecting humans and livestock. Unpredictable spatiotemporal dynamics of rabies within bat populations have precluded anticipation of outbreaks and undermined widespread bat culling programs. By analysing 1146 vampire bat-transmitted rabies (VBR) outbreaks in livestock across 12 years in Peru, we demonstrate that viral expansions into historically uninfected zones have doubled the recent burden of VBR. Viral expansions are geographically widespread, but severely constrained by high elevation peaks in the Andes mountains. Within Andean valleys, invasions form wavefronts that are advancing towards large, unvaccinated livestock populations that are heavily bitten by bats, which together will fuel high transmission and mortality. Using spatial models, we forecast the pathways of ongoing VBR epizootics across heterogeneous landscapes. These results directly inform vaccination strategies to mitigate impending viral emergence, reveal VBR as an emerging rather than an enzootic disease and create opportunities to test novel interventions to manage viruses in bat reservoirs
FCNC in the 3-3-1 model with right-handed neutrinos
Flavor changing neutral currents coming from a new non-universal neutral
Gauge-Boson and from the non-unitary quark mixing matrix for the
model with right handed neutrinos are
studied. By imposing as experimental constraints the measured values of the 3x3
quark mixing matrix, the neutral meson mixing, and the bounds measured values
for direct flavor changing neutral current processes, the largest mixing of the
known quarks with the exotic ones can be established, with new sources of
flavor changing neutral currents being identified. Our main result is that for
a value smaller than one, large rates of rare top decays such as
, , and (where g stands for the gluon field)
are obtained; but if the model can survive present
experimental limits only if the mass of the new neutral Gauge Boson becomes
larger that 10 TeV.Comment: 30 pages, 1 figure. Accepted for publication in Phys. Rev.
Unattainable extended spacetime regions in conformal gravity
The Janis-Newman-Winicour metric is a solution of Einstein's gravity
minimally coupled to a real massless scalar field. The -metric is
instead a vacuum solution of Einstein's gravity. These spacetimes have no
horizon and possess a naked singularity at a finite value of the radial
coordinate, where curvature invariants diverge and the spacetimes are
geodetically incomplete. In this paper, we reconsider these solutions in the
framework of conformal gravity and we show that it is possible to solve the
spacetime singularities with a suitable choice of the conformal factor. Now
curvature invariants remain finite over the whole spacetime. Massive particles
never reach the previous singular surface and massless particles can never do
it with a finite value of their affine parameter. Our results support the
conjecture according to which conformal gravity can fix the singularity problem
that plagues Einstein's gravity.Comment: 1+10 pages, 2 figures. v2: refereed versio
- …