2,574 research outputs found
Immune Responses in Human Necatoriasis: Association between Interleukin-5 Responses and Resistance to Reinfection
Cytokine and proliferative responses to Necator americanus infection were measured in a treatment-reinfection study of infected subjects from an area of Papua New Guinea where N. americanus is highly endemic. Before treatment, most subjects produced detectable interleukin (IL)4 (97%), IL-5 (86%), and interferon (IFN)-γ(64%) in response to adult N. americanus antigen. Pretreatment IFN-γ responses were negatively associated with hookworm burden, decreasing by 18 pg/mL for each increase of 1000 eggs/gram (epg) (n = 75; P < .01). Mean IFN-γ responses increased significantly after anthelmintic treatment, from 166 to 322 pg/mL (n = 42; P < .01). The intensity of reinfection was significantly negatively correlated with pretreatment IL-5 responses, decreasing by 551 epg for each 100 pg/mL increase in production of IL-5 (n = 51; P < .01). These data indicate that there is a mixed cytokine response in necatoriasis, with worm burdenassociated suppression of IFN-γ responses to adult N. americanus antigen. Resistance to reinfection is associated with the parasite-specific IL-5 response
Mirror displacement energies and neutron skins
A gross estimate of the neutron skin [0.80(5) fm] is extracted from
experimental proton radii, represented by a four parameter fit, and observed
mirror displacement energies (CDE). The calculation of the latter relies on an
accurately derived Coulomb energy and smooth averages of the charge symmetry
breaking potentials constrained to state of the art values. The only free
parameter is the neutron skin itself. The Nolen Schiffer anomaly is reduced to
small deviations (rms=127 keV) that exhibit a secular trend. It is argued that
with state of the art shell model calculations the anomaly should disappear.
Highly accurate fits to proton radii emerge as a fringe benefit.Comment: 4 pages 3 figures, superseeds first part of nucl-th/0104048 Present
is new extended version: 5 pages 4 figures. Explains more clearly the
achievements of the previous on
A simple expression for the ADM mass
We show by an almost elementary calculation that the ADM mass of an
asymptotically flat space can be computed as a limit involving a rate of change
of area of a closed 2-surface. The result is essentially the same as that given
by Brown and York. We will prove this result in two ways, first by direct
calculation from the original formula as given by Arnowitt, Deser and Misner
and second as a corollary of an earlier result by Brewin for the case of
simplicial spaces.Comment: 9 pages, 1 figur
Vector Manifestation and Fate of Vector Mesons in Dense Matter
We describe in-medium properties of hadrons in dense matter near chiral
restoration using a Wilsonian matching to QCD of an effective field theory with
hidden local symmetry at the chiral cutoff . We find that chiral
symmetry is restored in vector manifestation \`a la Harada and Yamawaki at a
critical matter density . We express the critical density in terms of QCD
correlators in dense matter at the matching scale. In a manner completely
analogous to what happens at the critical and at the critical
temperature , the vector meson mass is found to vanish (in the chiral
limit) at chiral restoration. This result provides a support for Brown-Rho
scaling predicted a decade ago.Comment: 14 pages, 2 figure
Search for Electronic Recoil Event Rate Modulation with 4 Years of XENON100 Data
We report on a search for electronic recoil event rate modulation signatures in the XENON100 data accumulated over a period of 4 yr, from January 2010 to January 2014. A profile likelihood method, which incorporates the stability of the XENON100 detector and the known electronic recoil background model, is used to quantify the significance of periodicity in the time distribution of events. There is a weak modulation signature at a period of 431-14+16 day in the low energy region of (2.0-5.8) keV in the single scatter event sample, with a global significance of 1.9σ; however, no other more significant modulation is observed. The significance of an annual modulation signature drops from 2.8σ, from a previous analysis of a subset of this data, to 1.8σ with all data combined. Single scatter events in the low energy region are thus used to exclude the DAMA/LIBRA annual modulation as being due to dark matter electron interactions via axial vector coupling at 5.7σ
Constraining the Spin-Dependent WIMP-Nucleon Cross Sections with XENON1T
We report the first experimental results on spin-dependent elastic weakly interacting massive particle (WIMP) nucleon scattering from the XENON1T dark matter search experiment. The analysis uses the full ton year exposure of XENON1T to constrain the spin-dependent proton-only and neutron-only cases. No significant signal excess is observed, and a profile likelihood ratio analysis is used to set exclusion limits on the WIMP-nucleon interactions. This includes the most stringent constraint to date on the WIMP-neutron cross section, with a minimum of 6.3 × 10−42 cm2 at 30 GeV/c2 and 90% confidence level. The results are compared with those from collider searches and used to exclude new parameter space in an isoscalar theory with an axial-vector mediator
Global Charges in Chern-Simons theory and the 2+1 black hole
We use the Regge-Teitelboim method to treat surface integrals in gauge
theories to find global charges in Chern-Simons theory. We derive the affine
and Virasoro generators as global charges associated with symmetries of the
boundary. The role of boundary conditions is clarified. We prove that for
diffeomorphisms that do not preserve the boundary there is a classical
contribution to the central charge in the Virasoro algebra. The example of
anti-de Sitter 2+1 gravity is considered in detail.Comment: Revtex, no figures, 26 pages. Important changes introduced. One
section added
Light and heavy element detection in thin sections of soils with the ion microprobe mass analyzer (IMMA).
Previous research with the scanning electron microscope (SEM)-energy dispersive X-ray analyzer (EDXRA) and the electron microprobe analyzer (EMA), showed that the detection of light elements in thin sections of soils was problematic or even impossible. Consequently initial experiments were performed with the ion microprobe mass analyzer (IMMA). These preliminary investigations were carried out on a piece of root material in soil (containing both light and heavy elements) which has a 'clayey' appearance and is known as a clayified root (Parfenova et al., 1964). The presence of heavier elements in this sample was investigated by SEM-EDXRA prior to IMMA analysis. The results with the ion microprobe mass analyzer showed that all chemical elements could be analyzed in the plant fragment. Also much higher elemental detection sensitivities were found with IMMA as compared to SEM-EDXRA and EMA. This even allowed ion imaging of trace elements. High-quality ion images of both light and heavy elements could be obtained in much shorter exposure times than with SEM-EDXRA and EMA techniques. Furthermore by analysis of fragmentation ('fingerprint') spectra additional information was obtained with respect to the chemical binding of the analyzed elements. Due to these preliminary results IMMA offers full possibilities for microchemical analysis in situ of all important elements in soil specimens. This technique considerably increases possibilities in soil micromorphology. (Abstract retrieved from CAB Abstracts by CABI’s permission
Critical behavior of the planar magnet model in three dimensions
We use a hybrid Monte Carlo algorithm in which a single-cluster update is
combined with the over-relaxation and Metropolis spin re-orientation algorithm.
Periodic boundary conditions were applied in all directions. We have calculated
the fourth-order cumulant in finite size lattices using the single-histogram
re-weighting method. Using finite-size scaling theory, we obtained the critical
temperature which is very different from that of the usual XY model. At the
critical temperature, we calculated the susceptibility and the magnetization on
lattices of size up to . Using finite-size scaling theory we accurately
determine the critical exponents of the model and find that =0.670(7),
=1.9696(37), and =0.515(2). Thus, we conclude that the
model belongs to the same universality class with the XY model, as expected.Comment: 11 pages, 5 figure
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