3,685 research outputs found
Polynomial Chaos Expansion method as a tool to evaluate and quantify field homogeneities of a novel waveguide RF Wien Filter
For the measurement of the electric dipole moment of protons and deuterons, a
novel waveguide RF Wien filter has been designed and will soon be integrated at
the COoler SYnchrotron at J\"ulich. The device operates at the harmonic
frequencies of the spin motion. It is based on a waveguide structure that is
capable of fulfilling the Wien filter condition ()
\textit{by design}. The full-wave calculations demonstrated that the waveguide
RF Wien filter is able to generate high-quality RF electric and magnetic
fields. In reality, mechanical tolerances and misalignments decrease the
simulated field quality, and it is therefore important to consider them in the
simulations. In particular, for the electric dipole moment measurement, it is
important to quantify the field errors systematically. Since Monte-Carlo
simulations are computationally very expensive, we discuss here an efficient
surrogate modeling scheme based on the Polynomial Chaos Expansion method to
compute the field quality in the presence of tolerances and misalignments and
subsequently to perform the sensitivity analysis at zero additional
computational cost.Comment: 12 pages, 19 figure
Insulin-like growth factor I is an independent coregulatory modulator of natural killer (NK) cell activity.
We aimed to investigate the natural killer (NK) cell activity in
hGH-deficient adults and to analyze the effect of insulin-like growth
factor (IGF)-I in uivo and in vitro on NK cell activity. NK cell activity
was measured in a 4-h nonisotopic assay with europium-labeled and
cryopreserved K-562 cells. NK-cell numbers were measured after
incubation with murine monoclonal CD3 and CD16 antibodies by flow
cytometry analysis. In a cross-sectional study, the basal and interferon-
p (IFN-P) stimulated (1000 IU/ml) NK cell activity of 15 hGHdeficient
patients and 15 age- and sex-matched controls was measured.
The percentages and absolute numbers of CD3./16+ NK-cells
were not significantly different in the patient vs. control group. The
basal and IFN-P stimulated NK cell activity however was significantly
decreased in the patient vs. control group at all effecter/target
(E/T) cell ratios from 12.5-100 (e.g. 17 ? 3 vs. 28 ? 3% lysis without
IFN-P, P < 0.05, and 42 t 4 vs. 57 2 4% lysis with IFN-0, P < 0.05;
both at E/T 50). IGF-I levels of patients and controls showed a significant
positive correlation with NK cell activity (r = 0.37; P < 0.05).
In an IGF-I in vitro study (IGF-I in vitro 250-1250 kg/L), the basal and
IFN-P stimulated NK cell activity of 13 hGH-deficient patients and of
18 normal subjects was significantly enhanced by IGF-I in vitro (e.g.
GH-deficient patients: 9 ? 2 us. 10 2 2% lysis without IFN-P, P < 0.05
and 25 + 4 vs. 30 + 4% lysis with IFN-/3, P < 0.005; and normal
subjects: 15 + 3 vs. 23 ? 3% lysis without IFN-/3, P < 0.001 and 35 2
4 us. 44 + 5% lysis with IFN-P, P < 0.001; both at IGF-I 500 pg/L).
In summary, in our cross-sectional study, adult GH-deficient patients
showed a significantly lower basal and IFN-P stimulated NK cell
activity than matched controls, despite equal NK cell numbers. IGF-I
levels of patients and controls showed a weak positive correlation with
NK cell activity. In an in vitro study, IGF-I significantly enhanced
basal and IFN-P stimulated NK cell activity of hGH-deficient patients
and also of normal subjects. The decreased NK cell activity in GHdeficient
patients may be caused at least in part by low serum IGF-I
levels. IGF-I appears to be an independent coregulatory modulator of
NK cell activity. (Endocrinology 137: 5332-5336, 1996
Electromagnetic Simulation and Design of a Novel Waveguide RF Wien Filter for Electric Dipole Moment Measurements of Protons and Deuterons
The conventional Wien filter is a device with orthogonal static magnetic and
electric fields, often used for velocity separation of charged particles. Here
we describe the electromagnetic design calculations for a novel waveguide RF
Wien filter that will be employed to solely manipulate the spins of protons or
deuterons at frequencies of about 0.1 to 2 MHz at the COoler SYnchrotron COSY
at J\"ulich. The device will be used in a future experiment that aims at
measuring the proton and deuteron electric dipole moments, which are expected
to be very small. Their determination, however, would have a huge impact on our
understanding of the universe.Comment: 10 pages, 10 figures, 4 table
HRSC Mapping Database: A New Tool to Collect and View Available HRSC-Based Geological Maps Worldwide
We present a new online database for quick and easy access to already published HRSC-based geological mappings on Mars
Radio-loud Active Galaxies in the Northern ROSAT All-Sky Survey III: New Spectroscopic Identifications from the RGB BL Lac Survey
We present new spectroscopic identifications for 169 objects in the
RASS-Green Bank (RGB) catalog of radio- and X-ray-emitting AGN. These data
significantly increase the fraction of bright RGB objects with classifications.
Specifically, we report and discuss the classification of 66 radio-loud
quasars, 53 BL Lacs, 33 Broad Line Radio Galaxies, 5 Narrow Line Radio
Galaxies, 1 Seyfert I galaxy and 11 galaxies or galaxies in clusters. Over 78%
of the identifications we present here are new. The observations we report were
undertaken as part of our targeted search program to identify a new, large
unbiased sample of BL Lac Objects and we therefore discuss the BL Lac sample
extensively. Unlike many previous surveys, we impose no selection criteria
based on optical morphology, color or broadband spectral energy distribution.
Our classifications are based solely on a carefully defined set of
self-consistent spectroscopic classification criteria. We show the 53 RGB
presented here exhibit transitional properties between normal galaxies and BL
Lacs discovered previously. We show there is no clear separation in CaII break
strength between RGB BL Lacs and galaxies, with the distribution of break
strengths varying smoothly between 0% and 50%. We also show that the newly
discovered RGB BL Lacs reside in a "zone of avoidance" in the log(S_x/S_r) vs.
log(S_o/S_r) diagram. This has important implications for BL Lac search
strategies since it shows that RASS BL Lac samples will be severely incomplete
if candidates are chosen only from among those objects with the highest S_x/S_r
flux ratios.Comment: 21 pages text, 189 Figures, 4 tables, LaTeX2E, 4.2MB tar file
(compressed); special style file paper.sty provide
First Results from MASIV: The Micro-Arcsecond Scintillation-Induced Variability Survey
We are undertaking a large-scale, Micro-Arcsecond Scintillation-Induced
Variability (MASIV) survey of the northern sky, Dec > 0 deg, at 4.9 GHz with
the VLA. Our objective is to construct a sample of 100 to 150 scintillating
extragalactic sources with which to examine both the microarcsecond structure
and the parent populations of these sources, and to probe the turbulent
interstellar medium responsible for the scintillation. We report on our first
epoch of observations which revealed variability on timescales ranging from
hours to days in 85 of 710 compact flat-spectrum sources. The number of highly
variable sources, those with RMS flux density variations greater than 4% of the
mean, increases with decreasing source flux density but rapid, large amplitude
variables such as J1819+3845 are very rare. When compared with a model for the
scintillation due to irregularities in a 500 pc thick electron layer, our
preliminary results indicate maximum brightness temperatures ~10E+12 K, similar
to those obtained from VLBI surveys even though interstellar scintillation is
not subject to the same angular resolution limit.Comment: 18 pages, 5 figures. To appear in the Astronomical Journa
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Challenges and Opportunities to Updating Prescribing Information for Longstanding Oncology Drugs.
A number of important drugs used to treat cancer-many of which serve as the backbone of modern chemotherapy regimens-have outdated prescribing information in their drug labeling. The Food and Drug Administration is undertaking a pilot project to develop a process and criteria for updating prescribing information for longstanding oncology drugs, based on the breadth of knowledge the cancer community has accumulated with the use of these drugs over time. This article highlights a number of considerations for labeling updates, including selecting priorities for updating; data sources and evidentiary criteria; as well as the risks, challenges, and opportunities for iterative review to ensure prescribing information for oncology drugs remains relevant to current clinical practice
Measuring the Polarization of a Rapidly Precessing Deuteron Beam
This paper describes a time-marking system that enables a measurement of the
in-plane (horizontal) polarization of a 0.97-GeV/c deuteron beam circulating in
the Cooler Synchrotron (COSY) at the Forschungszentrum J\"ulich. The clock time
of each polarimeter event is used to unfold the 120-kHz spin precession and
assign events to bins according to the direction of the horizontal
polarization. After accumulation for one or more seconds, the down-up
scattering asymmetry can be calculated for each direction and matched to a
sinusoidal function whose magnitude is proportional to the horizontal
polarization. This requires prior knowledge of the spin tune or polarization
precession rate. An initial estimate is refined by re-sorting the events as the
spin tune is adjusted across a narrow range and searching for the maximum
polarization magnitude. The result is biased toward polarization values that
are too large, in part because of statistical fluctuations but also because
sinusoidal fits to even random data will produce sizeable magnitudes when the
phase is left free to vary. An analysis procedure is described that matches the
time dependence of the horizontal polarization to templates based on
emittance-driven polarization loss while correcting for the positive bias. This
information will be used to study ways to extend the horizontal polarization
lifetime by correcting spin tune spread using ring sextupole fields and thereby
to support the feasibility of searching for an intrinsic electric dipole moment
using polarized beams in a storage ring. This paper is a combined effort of the
Storage Ring EDM Collaboration and the JEDI Collaboration.Comment: 28 pages, 15 figures, prepared for Physical Review ST - Accelerators
and Beam
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