687 research outputs found
Evidence of lumpy skin disease virus over-wintering by transstadial persistence in Amblyomma hebraeum and transovarial persistance in Rhipicephalus decoloratus ticks
Lumpy skin disease is a debilitating cattle disease caused by the lumpy skin
disease virus (LSDV), belonging to the genus Capripoxvirus. Epidemics of the disease
usually occur in summer, when insect activity is high. Limited information is available on
how LSDV persists during inter-epidemic periods. Transmission of LSDV by mosquitoes
such as Aedes aegypti has been shown to be mechanical, there is no carrier state in cattle
and the role of wildlife in the epidemiology of the disease seems to be of minor importance.
Recent studies in ticks have shown transstadial persistence of LSDV in Rhipicephalus
appendiculatus and Amblyomma hebraeum as well as transovarial persistence of
the virus in Rhipicephalus decoloratus, R. appendiculatus and A. hebraeum. The overwintering
of ticks off the host as part of their life cycles is well known: A. hebraeum and
R. appendiculatus over-winter, for example, on the ground as engorged nymphs/unfed
(emergent) adults while R. decoloratus over-winters on the ground as engorged females. In
this study, transstadial and transovarial persistence of LSDV from experimentally infected
A. hebraeum nymphs and R. decoloratus females after exposure to cold temperatures of
5 C at night and 20 C during the day for 2 months was reported. This observation
suggests possible over-wintering of the virus in these tick species.Combating Infectious Diseases of Livestock for International Development (CIDLID) research programme, the Department of International Biotechnology and Biological Sciences Research Council (BBSRC), the UK government, the Department for International Development (DFID) and the Scottish Government (CIDLID Project
Number BB/H009361/1).http://link.springer.com/journal/10493hb201
Spin pumping and magnetization dynamics in metallic multilayers
We study the magnetization dynamics in thin ferromagnetic films and small
ferromagnetic particles in contact with paramagnetic conductors. A moving
magnetization vector causes \textquotedblleft pumping\textquotedblright of
spins into adjacent nonmagnetic layers. This spin transfer affects the
magnetization dynamics similar to the Landau-Lifshitz-Gilbert phenomenology.
The additional Gilbert damping is significant for small ferromagnets, when the
nonmagnetic layers efficiently relax the injected spins, but the effect is
reduced when a spin accumulation build-up in the normal metal opposes the spin
pumping. The damping enhancement is governed by (and, in turn, can be used to
measure) the mixing conductance or spin-torque parameter of the
ferromagnet--normal-metal interface. Our theoretical findings are confirmed by
agreement with recent experiments in a variety of multilayer systems.Comment: 10 pages, 6 figure
Demonstration of lumpy skin disease virus infection in Amblyomma hebraeum and Rhipicephalus appendiculatus ticks using immunohistochemistry
Lumpy skin disease (LSD) is caused by lumpy skin disease virus (LSDV), a member of the genus
Capripoxvirus. Transmission of the virus has been associated with haematophagous insects such as Stomoxys
calcitrans as well as Aedes and Culex species of mosquitoes. Recent studies have reported the
transmission of the virus by Amblyomma hebraeum, Rhipicephalus appendiculatus, and Rhipicephalus decoloratus
ticks and the presence of LSDV in saliva of A. hebraeum and R. appendiculatus ticks. The aim of this
study was to determine which tick organs become infected by LSDV following intrastadial infection and
transstadial persistence of the virus in A. hebraeum and R. appendiculatus ticks. Nymphal and adult ticks
were orally infected by feeding them on LSDV-infected cattle. Partially fed adult ticks were processed for
testing while nymphs were fed to repletion and allowed to moult to adults before being processed for
testing. The infection in tick organs was determined by testing for the presence of the viral antigen using
monoclonal antibodies with immunohistochemical staining. The viral antigen was detected in salivary
glands, haemocytes, synganglia, ovaries, testes, fat bodies, and midgut. Since the virus was shown to be
able to cross the midgut wall and infect various tick organs, this may indicate potential for biological
development and transmission of LSDV in ticks. This study strengthens the previously reported evidence
of the occurrence of LSDV in tick saliva.http://www.elsevier.com/locate/ttbdishb2014ab201
Fluid Flow and Defect Formation in the Three-Dimensional Dendritic Structure of Nickel-Based Single Crystals
High sensitivity C-reactive protein distribution in the elderly: the Bambuí Cohort Study, Brazil
Global Search for New Physics with 2.0/fb at CDF
Data collected in Run II of the Fermilab Tevatron are searched for
indications of new electroweak-scale physics. Rather than focusing on
particular new physics scenarios, CDF data are analyzed for discrepancies with
the standard model prediction. A model-independent approach (Vista) considers
gross features of the data, and is sensitive to new large cross-section
physics. Further sensitivity to new physics is provided by two additional
algorithms: a Bump Hunter searches invariant mass distributions for "bumps"
that could indicate resonant production of new particles; and the Sleuth
procedure scans for data excesses at large summed transverse momentum. This
combined global search for new physics in 2.0/fb of ppbar collisions at
sqrt(s)=1.96 TeV reveals no indication of physics beyond the standard model.Comment: 8 pages, 7 figures. Final version which appeared in Physical Review D
Rapid Communication
Observation of Orbitally Excited B_s Mesons
We report the first observation of two narrow resonances consistent with
states of orbitally excited (L=1) B_s mesons using 1 fb^{-1} of ppbar
collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the
Fermilab Tevatron. We use two-body decays into K^- and B^+ mesons reconstructed
as B^+ \to J/\psi K^+, J/\psi \to \mu^+ \mu^- or B^+ \to \bar{D}^0 \pi^+,
\bar{D}^0 \to K^+ \pi^-. We deduce the masses of the two states to be m(B_{s1})
= 5829.4 +- 0.7 MeV/c^2 and m(B_{s2}^*) = 5839.7 +- 0.7 MeV/c^2.Comment: Version accepted and published by Phys. Rev. Let
Shrinking a large dataset to identify variables associated with increased risk of Plasmodium falciparum infection in Western Kenya
Large datasets are often not amenable to analysis using traditional single-step approaches. Here, our general objective was to apply imputation techniques, principal component analysis (PCA), elastic net and generalized linear models to a large dataset in a systematic approach to extract the most meaningful predictors for a health outcome. We extracted predictors for Plasmodium falciparum infection, from a large covariate dataset while facing limited numbers of observations, using data from the People, Animals, and their Zoonoses (PAZ) project to demonstrate these techniques: data collected from 415 homesteads in western Kenya, contained over 1500 variables that describe the health, environment, and social factors of the humans, livestock, and the homesteads in which they reside. The wide, sparse dataset was simplified to 42 predictors of P. falciparum malaria infection and wealth rankings were produced for all homesteads. The 42 predictors make biological sense and are supported by previous studies. This systematic data-mining approach we used would make many large datasets more manageable and informative for decision-making processes and health policy prioritization
Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set
We report a measurement of the bottom-strange meson mixing phase \beta_s
using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays
in which the quark-flavor content of the bottom-strange meson is identified at
production. This measurement uses the full data set of proton-antiproton
collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment
at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity.
We report confidence regions in the two-dimensional space of \beta_s and the
B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2,
-1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in
agreement with the standard model expectation. Assuming the standard model
value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +-
0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +-
0.009 (syst) ps, which are consistent and competitive with determinations by
other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
- …