6,784 research outputs found
Mycobacterium avium subsp. paratuberculosis Proteome Changes Profoundly in Milk
Mycobacterium avium subspecies paratuberculosis (MAP) are detectable viable in milk and other dairy products. The molecular mechanisms allowing the adaptation of MAP in these products are still poorly understood. To obtain information about respective adaptation of MAP in milk, we differentially analyzed the proteomes of MAP cultivated for 48 h in either milk at 37 °C or 4 °C or Middlebrook 7H9 broth as a control. From a total of 2197 MAP proteins identified, 242 proteins were at least fivefold higher in abundance in milk. MAP responded to the nutritional shortage in milk with upregulation of 32% of proteins with function in metabolism and 17% in fatty acid metabolism/synthesis. Additionally, MAP upregulated clusters of 19% proteins with roles in stress responses and immune evasion, 19% in transcription/translation, and 13% in bacterial cell wall synthesis. Dut, MmpL4_1, and RecA were only detected in MAP incubated in milk, pointing to very important roles of these proteins for MAP coping with a stressful environment. Dut is essential and plays an exclusive role for growth, MmpL4_1 for virulence through secretion of specific lipids, and RecA for SOS response of mycobacteria. Further, 35 candidates with stable expression in all conditions were detected, which could serve as targets for detection. Data are available via ProteomeXchange with identifier PXD027444
Wavelength-dependent reflectivity changes on gold at elevated electronic temperatures
Upon the excitation by an ultrashort laser pulse the conditions in a material
can drastically change, altering its optical properties and therefore the
relative amount of absorbed energy, a quan- tity relevant for determining the
damage threshold and for developing a detailed simulation of a structuring
process. The subject of interest in this work is the d-band metal gold which
has an absorption edge marking the transition of free valence electrons and an
absorbing deep d-band with bound electrons. Reflectivity changes are observed
in experiment over a broad spectral range at ablation conditions. To understand
the involved processes the laser excitation is modeled by a com- bination of
first principle calculations with a two-temperature model. The description is
kept most general and applied to realistically simulate the transfer of the
absorbed energy of a Gaussian laser pulse into the electronic system at every
point in space at every instance of time. An electronic temperature-dependent
reflectivity map is calculated, describing the out of equilibrium reflectivity
during laser excitation for photon energies from 0.9 - 6.4 eV, including inter-
and intra-band transi- tions and a temperature-dependent damping factor. The
main mechanisms are identified explaining the electronic temperature-dependent
change in reflectivity: broadening of the edge of the occu- pied/unoccupied
states around the chemical potential , also leading to a shift of the
and an increase of the collision rate of free s/p-band electrons with
bound d-band holes
Lycoris -- a large-area, high resolution beam telescope
A high-resolution beam telescope is one of the most important and demanding
infrastructure components at any test beam facility. Its main purpose is to
provide reference particle tracks from the incoming test beam particles to the
test beam users, which allows measurement of the performance of the
device-under-test (DUT). \LYCORIS, a six-plane compact beam telescope with an
active area of 10\SI{10}{\square\centi\metre} (extensible to
10\SI{20}{\square\centi\metre}) was installed at the \DIITBF in 2019,
to provide a precise momentum measurement in a \SI{1}{\tesla} solenoid magnet
or to provide tracking over a large area. The overall design of \LYCORIS will
be described as well as the performance of the chosen silicon sensor. The
\SI{25}{\micro\metre} pitch micro-strip sensor used for \LYCORIS was originally
designed for the \SID detector concept for the International Linear Collider.
It adopts a second metallization layer to route signals from strips to the
bump-bonded \KPIX ASIC and uses a wire-bonded flex cable for the connection to
the DAQ and the power supply system. This arrangement eliminates the need for a
dedicated hybrid PCB. Its performance was tested for the first time in this
project. The system has been evaluated at the \DIITBF in several test-beam
campaigns and has demonstrated an average single-point resolution of
\SI{7.07}{\micro\meter}.Comment: 43 pages, 37 figure
Resolved Photon Processes
We review the present level of knowledge of the hadronic structure of the
photon, as revealed in interactions involving quarks and gluons ``in" the
photon. The concept of photon structure functions is introduced in the
description of deep--inelastic scattering, and existing
parametrizations of the parton densities in the photon are reviewed. We then
turn to hard \gamp\ and \gaga\ collisions, where we treat the production of
jets, heavy quarks, hard (direct) photons, \jpsi\ mesons, and lepton pairs. We
also comment on issues that go beyond perturbation theory, including recent
attempts at a comprehensive description of both hard and soft \gamp\ and \gaga\
interactions. We conclude with a list of open problems.Comment: LaTeX with equation.sty, 85 pages, 29 figures (not included). A
complete PS file of the paper, including figures, can be obtained via
anonymous ftp from
ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-898.ps.
Search for Doubly-Charged Higgs Boson Production at HERA
A search for the single production of doubly-charged Higgs bosons H^{\pm \pm}
in ep collisions is presented. The signal is searched for via the Higgs decays
into a high mass pair of same charge leptons, one of them being an electron.
The analysis uses up to 118 pb^{-1} of ep data collected by the H1 experiment
at HERA. No evidence for doubly-charged Higgs production is observed and mass
dependent upper limits are derived on the Yukawa couplings h_{el} of the Higgs
boson to an electron-lepton pair. Assuming that the doubly-charged Higgs only
decays into an electron and a muon via a coupling of electromagnetic strength
h_{e \mu} = \sqrt{4 \pi \alpha_{em}} = 0.3, a lower limit of 141 GeV on the
H^{\pm\pm} mass is obtained at the 95% confidence level. For a doubly-charged
Higgs decaying only into an electron and a tau and a coupling h_{e\tau} = 0.3,
masses below 112 GeV are ruled out.Comment: 15 pages, 3 figures, 1 tabl
Forward pi^0 Production and Associated Transverse Energy Flow in Deep-Inelastic Scattering at HERA
Deep-inelastic positron-proton interactions at low values of Bjorken-x down
to x \approx 4.10^-5 which give rise to high transverse momentum pi^0 mesons
are studied with the H1 experiment at HERA. The inclusive cross section for
pi^0 mesons produced at small angles with respect to the proton remnant (the
forward region) is presented as a function of the transverse momentum and
energy of the pi^0 and of the four-momentum transfer Q^2 and Bjorken-x.
Measurements are also presented of the transverse energy flow in events
containing a forward pi^0 meson. Hadronic final state calculations based on QCD
models implementing different parton evolution schemes are confronted with the
data.Comment: 27 pages, 8 figures and 3 table
Measurements of branching fraction ratios and CP-asymmetries in suppressed B^- -> D(-> K^+ pi^-)K^- and B^- -> D(-> K^+ pi^-)pi^- decays
We report the first reconstruction in hadron collisions of the suppressed
decays B^- -> D(-> K^+ pi^-)K^- and B^- -> D(-> K^+ pi^-)pi^-, sensitive to the
CKM phase gamma, using data from 7 fb^-1 of integrated luminosity collected by
the CDF II detector at the Tevatron collider. We reconstruct a signal for the
B^- -> D(-> K^+ pi^-)K^- suppressed mode with a significance of 3.2 standard
deviations, and measure the ratios of the suppressed to favored branching
fractions R(K) = [22.0 \pm 8.6(stat)\pm 2.6(syst)]\times 10^-3, R^+(K) =
[42.6\pm 13.7(stat)\pm 2.8(syst)]\times 10^-3, R^-(K)= [3.8\pm 10.3(stat)\pm
2.7(syst]\times 10^-3, as well as the direct CP-violating asymmetry A(K) =
-0.82\pm 0.44(stat)\pm 0.09(syst) of this mode. Corresponding quantities for
B^- -> D(-> K^+ pi^-)pi^- decay are also reported.Comment: 8 pages, 1 figure, accepted by Phys.Rev.D Rapid Communications for
Publicatio
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
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