142 research outputs found
Usutu virus in blackbirds (Turdus merula) with clinical signs, a case study from northern Italy
Usutu virus (USUV) is a mosquito-borne virus belonging to the family Flaviviridae, genus Flavivirus. Natural transmission
cycle of USUV involves mosquitoes and birds, so humans and other mammals are considered incidental hosts. In this study,
USUV infection was diagnosed in all wild blackbirds, collected from July to September 2018 in a wildlife recovery center
in the province of Bologna, in the Emilia-Romagna region, northern Italy. All blackbirds showed neurological clinical signs,
such as overturning, pedaling, and incoordination. Moreover, the subjects died shortly after arriving at the hospitalization
center. Virological investigations were performed by real-time PCR on frozen samples of the spleen, kidney, myocardium,
and brain for the detection of Usutu (USUV) and West Nile (WNV) viruses. The small and large intestine were used as a
matrix for the detection of Newcastle disease virus (NDV). All 56 subjects with neurological clinical signs were positive
for USUV, only one subject (1.8%) tested positive for WNV, and no subject was positive for NDV. The most represented
age class was class 1 J (58.9%), followed by class 3 (25.0%), and lastly from class 4 (16.1%). Most of the blackbirds before
dying were in good (51.8%) and fair (39.3%) nutritional status, while only five subjects (8.9%) were cachectic. The USUV
genomes detected in the blackbirds of this study fall within the sub-clade already called EU2 that has been detected since
2009 in the Emilia-Romagna region. Neurological clinical signs in USUV-affected blackbirds are still widely discussed and
there are few works in the literature. Although our results require further studies, we believe them to be useful for understanding
the clinical signs of Usutu virus in blackbirds, helping to increase the knowledge of this zoonotic agent in wild species
and to understand its effect on the ecosystem. The goal of this study was to report—in the context of the regional passive
surveillance program—the detection of USUV RNA in its most important amplifying host, the common blackbird, when
showing clinical signs before death
Hybridization of Guided Surface Acoustic Modes in Unconsolidated Granular Media by a Resonant Metasurface
We investigate the interaction of guided surface acoustic modes (GSAMs) in unconsolidated granular media with a metasurface, consisting of an array of vertical oscillators. We experimentally observe the hybridization of the lowest-order GSAM at the metasurface resonance, and note the absence of mode delocalization found in homogeneous media. Our numerical studies reveal how the stiffness gradient induced by gravity in granular media causes a down-conversion of all the higher-order GSAMs, which preserves the acoustic energy confinement. We anticipate these findings to have implications in the design of seismic-wave protection devices in stratified soils
On the NLO QCD corrections to the production of the heaviest neutral Higgs scalar in the MSSM
We present a calculation of the two-loop top-stop-gluino contributions to
Higgs production via gluon fusion in the MSSM. By means of an asymptotic
expansion in the heavy particle masses, we obtain explicit and compact analytic
formulae that are valid when the Higgs and the top quark are lighter than stops
and gluino, without assuming a specific hierarchy between the Higgs mass and
the top mass. Being applicable to the heaviest Higgs scalar in a significant
region of the MSSM parameter space, our results complement earlier ones
obtained with a Taylor expansion in the Higgs mass, and can be easily
implemented in computer codes to provide an efficient and accurate
determination of the Higgs production cross section.Comment: 18 pages, 4 figure
Probing the low transverse momentum domain of Z production with novel variables
The measurement of the low transverse momentum region of vector boson
production in Drell-Yan processes has long been invaluable to testing our
knowledge of QCD dynamics both beyond fixed-order in perturbation theory as
well as in the non-perturbative region. Recently the D\O\ collaboration have
introduced novel variables which lead to improved measurements compared to the
case of the standard QT variable. To complement this improvement on the
experimental side, we develop here a complete phenomenological study dedicated
in particular to the new \phi* variable. We compare our study, which contains
the state-of-the-art next-to-next-to-leading resummation of large logarithms
and a smooth matching to the full next-to-leading order result, to the
experimental data and find excellent agreement over essentially the entire
range of \phi*, even without direct inclusion of non-perturbative effects. We
comment on our findings and on the potential for future studies to constrain
non-perturbative behaviour.Comment: 20 pages, 7 figures. Version accepted for publication in JHEP. A
figure with comparison to RESBOS has been adde
The CCFM Monte Carlo generator CASCADE 2.2.0
CASCADE is a full hadron level Monte Carlo event generator for ep, \gamma p
and p\bar{p} and pp processes, which uses the CCFM evolution equation for the
initial state cascade in a backward evolution approach supplemented with off -
shell matrix elements for the hard scattering. A detailed program description
is given, with emphasis on parameters the user wants to change and variables
which completely specify the generated events
Hybridization of Guided Surface Acoustic Modes in Unconsolidated Granular Media by a Resonant Metasurface
We investigate the interaction of guided surface acoustic modes (GSAMs) in unconsolidated granular media with a metasurface, consisting of an array of vertical oscillators. We experimentally observe the hybridization of the lowest-order GSAM at the metasurface resonance, and note the absence of mode delocalization found in homogeneous media. Our numerical studies reveal how the stiffness gradient induced by gravity in granular media causes a down-conversion of all the higher-order GSAMs, which preserves the acoustic energy confinement. We anticipate these findings to have implications in the design of seismic-wave protection devices in stratified soils
Predictions for Higgs production at the Tevatron and the associated uncertainties
We update the theoretical predictions for the production cross sections of
the Standard Model Higgs boson at the Fermilab Tevatron collider, focusing on
the two main search channels, the gluon-gluon fusion mechanism and
the Higgs-strahlung processes with , including all
relevant higher order QCD and electroweak corrections in perturbation theory.
We then estimate the various uncertainties affecting these predictions: the
scale uncertainties which are viewed as a measure of the unknown higher order
effects, the uncertainties from the parton distribution functions and the
related errors on the strong coupling constant, as well as the uncertainties
due to the use of an effective theory approach in the determination of the
radiative corrections in the process at next-to-next-to-leading
order. We find that while the cross sections are well under control in the
Higgs--strahlung processes, the theoretical uncertainties are rather large in
the case of the gluon-gluon fusion channel, possibly shifting the central
values of the next-to-next-to-leading order cross sections by more than
. These uncertainties are thus significantly larger than the
error assumed by the CDF and D0 experiments in their recent
analysis that has excluded the Higgs mass range 162-166 GeV at the 95%
confidence level. These exclusion limits should be, therefore, reconsidered in
the light of these large theoretical uncertainties.Comment: 40 pages, 12 figures. A few typos are corrected and some updated
numbers are provide
Jet vetoing at the LHC
We study the effect of a veto on additional jets in the rapidity region
between a pair of high transverse momentum jets at the LHC. We aim to sum the
most important logarithms in the ratio of the jet transverse momentum to the
veto scale and to that end we attempt to assess the significance of the
super-leading logarithms that appear at high orders in the perturbative
expansion. We also compare our results to those of HERWIG++, in an attempt to
ascertain the accuracy of the angular ordered parton shower. We find that there
are large corrections that arise for large enough jet transverse momenta as a
consequence of Coulomb gluon exchanges.Comment: 25 page
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