88 research outputs found
Limits on WWZ and WW\gamma couplings from p\bar{p}\to e\nu jj X events at \sqrt{s} = 1.8 TeV
We present limits on anomalous WWZ and WW-gamma couplings from a search for
WW and WZ production in p-bar p collisions at sqrt(s)=1.8 TeV. We use p-bar p
-> e-nu jjX events recorded with the D0 detector at the Fermilab Tevatron
Collider during the 1992-1995 run. The data sample corresponds to an integrated
luminosity of 96.0+-5.1 pb^(-1). Assuming identical WWZ and WW-gamma coupling
parameters, the 95% CL limits on the CP-conserving couplings are
-0.33<lambda<0.36 (Delta-kappa=0) and -0.43<Delta-kappa<0.59 (lambda=0), for a
form factor scale Lambda = 2.0 TeV. Limits based on other assumptions are also
presented.Comment: 11 pages, 2 figures, 2 table
Zgamma Production in pbarp Collisions at sqrt(s)=1.8 TeV and Limits on Anomalous ZZgamma and Zgammagamma Couplings
We present a study of Z +gamma + X production in p-bar p collisions at
sqrt{S}=1.8 TeV from 97 (87) pb^{-1} of data collected in the eegamma
(mumugamma) decay channel with the D0 detector at Fermilab. The event yield and
kinematic characteristics are consistent with the Standard Model predictions.
We obtain limits on anomalous ZZgamma and Zgammagamma couplings for form factor
scales Lambda = 500 GeV and Lambda = 750 GeV. Combining this analysis with our
previous results yields 95% CL limits |h{Z}_{30}| < 0.36, |h{Z}_{40}| < 0.05,
|h{gamma}_{30}| < 0.37, and |h{gamma}_{40}| < 0.05 for a form factor scale
Lambda=750 GeV.Comment: 17 Pages including 2 Figures. Submitted to PR
A Measurement of the W Boson Mass
We report a measurement of the W boson mass based on an integrated luminosity
of 82 pb from \ppbar collisions at TeV recorded in
1994--1995 by the \Dzero detector at the Fermilab Tevatron. We identify W
bosons by their decays to and extract the mass by fitting the transverse
mass spectrum from 28,323 W boson candidates. A sample of 3,563 dielectron
events, mostly due to Z to ee decays, constrains models of W boson production
and the detector. We measure \mw=80.44\pm0.10(stat)\pm0.07(syst)~GeV. By
combining this measurement with our result from the 1992--1993 data set, we
obtain \mw=80.43\pm0.11 GeV.Comment: 11 pages, 5 figure
Changing expression of vertebrate immunity genes in an anthropogenic environment: a controlled experiment
Background: The effect of anthropogenic environments on the function of the vertebrate immune system is a problem of general importance. For example, it relates to the increasing rates of immunologically-based disease in modern human populations and to the desirability of identifying optimal immune function in domesticated animals. Despite this importance, our present understanding is compromised by a deficit of experimental studies that make adequately matched comparisons between wild and captive vertebrates.
Results: We transferred post-larval fishes (three-spined sticklebacks), collected in the wild, to an anthropogenic (captive) environment. We then monitored, over 11 months, how the systemic expression of immunity genes changed in comparison to cohort-matched wild individuals in the
originator population (total n = 299). We found that a range of innate (lyz, defbl2, il1r-like, tbk1)and adaptive (cd8a, igmh) immunity genes were up-regulated in captivity, accompanied by an increase in expression of the antioxidant enzyme, gpx4a. For some genes previously known to show seasonality in the wild, this appeared to be reduced in captive fishes. Captive fishes tended to express immunity genes, including igzh, foxp3b, lyz, defbl2, and il1r-like, more variably. Furthermore, although gene co-expression patterns (analyzed through gene-by-gene correlations and mutual information theory based networks) shared common structure in wild and captive fishes, there was also significant divergence. For one gene in particular, defbl2,
high expression was associated with adverse health outcomes in captive fishes.
Conclusion: Taken together, these results demonstrate widespread regulatory changes in the immune system in captive populations, and that the expression of immunity genes is more constrained in the wild. An increase in constitutive systemic immune activity, such as we
observed here, may alter the risk of immunopathology and contribute to variance in health in vertebrate populations exposed to anthropogenic environments
Identification of Candida glabrata genes involved in pH modulation and modification of the phagosomal environment in macrophages
notes: PMCID: PMC4006850types: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov'tCandida glabrata currently ranks as the second most frequent cause of invasive candidiasis. Our previous work has shown that C. glabrata is adapted to intracellular survival in macrophages and replicates within non-acidified late endosomal-stage phagosomes. In contrast, heat killed yeasts are found in acidified matured phagosomes. In the present study, we aimed at elucidating the processes leading to inhibition of phagosome acidification and maturation. We show that phagosomes containing viable C. glabrata cells do not fuse with pre-labeled lysosomes and possess low phagosomal hydrolase activity. Inhibition of acidification occurs independent of macrophage type (human/murine), differentiation (M1-/M2-type) or activation status (vitamin D3 stimulation). We observed no differential activation of macrophage MAPK or NFκB signaling cascades downstream of pattern recognition receptors after internalization of viable compared to heat killed yeasts, but Syk activation decayed faster in macrophages containing viable yeasts. Thus, delivery of viable yeasts to non-matured phagosomes is likely not triggered by initial recognition events via MAPK or NFκB signaling, but Syk activation may be involved. Although V-ATPase is abundant in C. glabrata phagosomes, the influence of this proton pump on intracellular survival is low since blocking V-ATPase activity with bafilomycin A1 has no influence on fungal viability. Active pH modulation is one possible fungal strategy to change phagosome pH. In fact, C. glabrata is able to alkalinize its extracellular environment, when growing on amino acids as the sole carbon source in vitro. By screening a C. glabrata mutant library we identified genes important for environmental alkalinization that were further tested for their impact on phagosome pH. We found that the lack of fungal mannosyltransferases resulted in severely reduced alkalinization in vitro and in the delivery of C. glabrata to acidified phagosomes. Therefore, protein mannosylation may play a key role in alterations of phagosomal properties caused by C. glabrata.Deutsche ForschungsgemeinschaftNational Institutes for HealthWellcome TrustBBSR
Multivalent HA DNA Vaccination Protects against Highly Pathogenic H5N1 Avian Influenza Infection in Chickens and Mice
Sustained outbreaks of highly pathogenic avian influenza (HPAI) H5N1 in avian species increase the risk of reassortment and adaptation to humans. The ability to contain its spread in chickens would reduce this threat and help maintain the capacity for egg-based vaccine production. While vaccines offer the potential to control avian disease, a major concern of current vaccines is their potency and inability to protect against evolving avian influenza viruses.The ability of DNA vaccines encoding hemagglutinin (HA) proteins from different HPAI H5N1 serotypes was evaluated for its ability to elicit neutralizing antibodies and to protect against homologous and heterologous HPAI H5N1 strain challenge in mice and chickens after DNA immunization by needle and syringe or with a pressure injection device. These vaccines elicited antibodies that neutralized multiple strains of HPAI H5N1 when given in combinations containing up to 10 HAs. The response was dose-dependent, and breadth was determined by the choice of the influenza virus HA in the vaccine. Monovalent and trivalent HA vaccines were tested first in mice and conferred protection against lethal H5N1 A/Vietnam/1203/2004 challenge 68 weeks after vaccination. In chickens, protection was observed against heterologous strains of HPAI H5N1 after vaccination with a trivalent H5 serotype DNA vaccine with doses as low as 5 microg DNA given twice either by intramuscular needle injection or with a needle-free device.DNA vaccines offer a generic approach to influenza virus immunization applicable to multiple animal species. In addition, the ability to substitute plasmids encoding different strains enables rapid adaptation of the vaccine to newly evolving field isolates
Study of the ZZ\gamma and Z\gamma\gamma Couplings in Z(\nu\nu)\gamma Production
We have measured the ZZ-gamma and Z-gamma-gamma couplings by studying p-bar p
-> (missing ET) gamma + X events at sqrt(s)=1.8 TeV with the D0 detector at the
Fermilab Tevatron Collider. This first study of hadronic Z-gamma production in
the neutrino decay channel gives the most stringent limits on anomalous
couplings available. A fit to the transverse energy spectrum of the photon in
the candidate event sample, based on a data set corresponding to an integrated
luminosity of 13.1 pb^(-1), yields 95% CL limits on the anomalous CP-conserving
ZZ-gamma couplings of |h^Z_(30)|<0.9, |h^Z_(40)|<0.21, for a form-factor scale
Lambda = 500 GeV. Combining these results with our previous measurement using Z
-> ee and mu-mu yields the limits:|h^Z_(30)|<0.8, |h^Z_(40)|<0.19 (Lambda = 500
GeV) and |h^Z_(30)|<0.4, |h^Z_(40)|<0.06 (Lambda = 750 GeV).Comment: 10 pages, 2 figures, 2 table
Studies of Gauge Boson Pair Production and Trilinear Couplings
The gauge boson pair production processes Wg, WW, WZ, and Zg were studied
using pbarp collisions corresponding to an integrated luminosity of ~14 pb-1 at
a center-of-mass energy of sqrt(s) = 1.8 TeV. Analysis of Wg prod with
subsequent W boson decay to lv (l=e,mu) is reported, including a fit to the pT
spectrum of the photons which leads to limits on anomalous WWg couplings. A
search for WW prod with subsequent decay to l-lbar-v-vbar (l=e,mu) is presented
leading to an upper limit on the WW prod cross section and limits on anomalous
WWg and WWZ couplings. A search for high pT W bosons in WW and WZ prod is
described, where one W boson decays to an ev and the second W boson or the Z
boson decays to two jets. A maximum likelihood fit to the pT spectrum of W
bosons resulted in limits on anomalous WWg and WWZ couplings. A combined fit to
the three data sets which provided the tightest limits on anomalous WWg and WWZ
couplings is also described. Limits on anomalous ZZg and Zgg couplings are
presented from an analysis of the photon ET spectrum in Zg events in the decay
channels (ee, mu-mu, and v-vbar) of the Z boson.Comment: 77 Pages including 40 Figures. Submitted to PR
Limits on Anomalous Couplings from Events at TeV
We have measured the gauge boson coupling parameters using
() events at TeV. The
data, corresponding to an integrated luminosity of 89.1 pb^{-1}, were collected
using the D0 detector at the Fermilab Tevatron Collider. The measured cross
section times branching ratio for with >
10 GeV/c and is pb, in
agreement with the Standard Model prediction. The one degree of freedom 95%
confidence level limits on individual CP-conserving parameters are
and . Similar limits are set on
the CP}violating coupling parameters.Comment: 10 pages, including two figures. Paper submitted to Phys. Rev. Let
Search for the Trilepton Signature from the Associated Production of SUSY Chi_1^(+-) Chi_2^0 Gauginos
We report on a search for the trilepton signature from the associated
production of supersymmetric gaugino pairs, Chi_1^(+-) Chi_2^0, within the
context of minimal supersymmetric models that conserve R-parity. This search
uses 95 pb^-1 of data taken with the \D0 detector at Fermilab's Tevatron
collider at \sqrt{s} = 1.8 TeV. No evidence of a trilepton signature has been
found, and a limit on the production cross section times branching fraction to
trileptons as a function of Chi_1^(+-) mass is given.Comment: 16 pages, Latex (uses REVTeX V 3.0 style file), submitted to PR
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