14,815 research outputs found
Minimising bias in an un-masked, pragmatic rct comparing two treatment pathways for glaucoma by the use of decision support software - the light trial experience
ragmatic trials of treatment pathways can require patient awareness of treatment allocation in order to better represent clinical reality, for example when concordance with a treatment has an important effect on outcome. Conversely, masking of treating clinicians to allocation group can be impossible when full clinical assessment requires knowledge of the current treatments, resources do not permit separate teams for treatment and assessment or when such duplication of clinician contact might affect an outcome such as patient experience.
The LiGHT trial is a 718 subject multi-centre 6-year NIHR-funded study of two treatment pathways for glaucoma with outcome measures of health related quality of life and cost effectiveness. We aimed to minimise variation in aspects of clinical behaviour that might introduce bias by affecting either of these outcomes
Spitzer IRAC Photometry for Time Series in Crowded Fields
We develop a new photometry algorithm that is optimized for time
series in crowded fields and that is particularly adapted to faint and/or
heavily blended targets. We apply this to the 170 targets from the 2015
microlensing campaign and present the results of three variants of
this algorithm in an online catalog. We present detailed accounts of the
application of this algorithm to two difficult cases, one very faint and the
other very crowded. Several of 's instrumental characteristics that
drive the specific features of this algorithm are shared by and
, implying that these features may prove to be a useful starting point
for algorithms designed for microlensing campaigns by these other missions.Comment: accepted for publication in The Astrophysical Journal Supplement,
online catalog available at http://www.astronomy.ohio-state.edu/Spitzer2015
OGLE-2016-BLG-0613LABb: A Microlensing Planet in a Binary System
We present the analysis of OGLE-2016-BLG-0613, for which the lensing light
curve appears to be that of a typical binary-lens event with two caustic spikes
but with a discontinuous feature on the trough between the spikes. We find that
the discontinuous feature was produced by a planetary companion to the binary
lens. We find 4 degenerate triple-lens solution classes, each composed of a
pair of solutions according to the well-known wide/close planetary degeneracy.
One of these solution classes is excluded due to its relatively poor fit. For
the remaining three pairs of solutions, the most-likely primary mass is about
while the planet is a super-Jupiter. In all cases the
system lies in the Galactic disk, about half-way toward the Galactic bulge.
However, in one of these three solution classes, the secondary of the binary
system is a low-mass brown dwarf, with relative mass ratios (1 : 0.03 : 0.003),
while in the two others the masses of the binary components are comparable.
These two possibilities can be distinguished in about 2024 when the measured
lens-source relative proper motion will permit separate resolution of the lens
and source.Comment: 14 pages, 9 figure
Spitzer as a microlens parallax satellite : mass and distance measurements of the binary lens system OGLE-2014-BLG-1050L
We report the first mass and distance measurements of a caustic-crossing binary system OGLE-2014-BLG-1050 L using the space-based microlens parallax method. Spitzer captured the second caustic crossing of the event, which occurred ~10 days before that seen from Earth. Due to the coincidence that the source-lens relative motion was almost parallel to the direction of the binary-lens axis, the fourfold degeneracy, which was known before only to occur in single-lens events, persists in this case, leading to either a lower-mass (0.2 and 0.07 MΘ) binary at ~1.1 kpc or a higher-mass (0.9 and 0.35 MΘ) binary at ~3.5 kpc. However, the latter solution is strongly preferred for reasons including blending and lensing probability. OGLE-2014-BLG-1050 L demonstrates the power of microlens parallax in probing stellar and substellar binaries.Publisher PDFPeer reviewe
Limits on light WIMPs from the CDEX-1 experiment with a p-type point-contact germanium detector at the China Jingping Underground Laboratory
We report results of a search for light Dark Matter WIMPs with CDEX-1
experiment at the China Jinping Underground Laboratory, based on 53.9 kg-days
of data from a p-type point-contact germanium detector enclosed by a NaI(Tl)
crystal scintillator as anti-Compton detector. The event rate and spectrum
above the analysis threshold of 475 eVee are consistent with the understood
background model. Part of the allowed regions for WIMP-nucleus coherent elastic
scattering at WIMP mass of 6-20 GeV are probed and excluded. Independent of
interaction channels, this result contradicts the interpretation that the
anomalous excesses of the CoGeNT experiment are induced by Dark Matter, since
identical detector techniques are used in both experiments.Comment: 5 pages, 5 figure
A Unified Approach to the Classical Statistical Analysis of Small Signals
We give a classical confidence belt construction which unifies the treatment
of upper confidence limits for null results and two-sided confidence intervals
for non-null results. The unified treatment solves a problem (apparently not
previously recognized) that the choice of upper limit or two-sided intervals
leads to intervals which are not confidence intervals if the choice is based on
the data. We apply the construction to two related problems which have recently
been a battle-ground between classical and Bayesian statistics: Poisson
processes with background, and Gaussian errors with a bounded physical region.
In contrast with the usual classical construction for upper limits, our
construction avoids unphysical confidence intervals. In contrast with some
popular Bayesian intervals, our intervals eliminate conservatism (frequentist
coverage greater than the stated confidence) in the Gaussian case and reduce it
to a level dictated by discreteness in the Poisson case. We generalize the
method in order to apply it to analysis of experiments searching for neutrino
oscillations. We show that this technique both gives correct coverage and is
powerful, while other classical techniques that have been used by neutrino
oscillation search experiments fail one or both of these criteria.Comment: 40 pages, 15 figures. Changes 15-Dec-99 to agree more closely with
published version. A few small changes, plus the two substantive changes we
made in proof back in 1998: 1) The definition of "sensitivity" in Sec. V(C).
It was inconsistent with our actual definition in Sec. VI. 2) "Note added in
proof" at end of the Conclusio
JLab Measurement of the He Charge Form Factor at Large Momentum Transfers
The charge form factor of ^4He has been extracted in the range 29 fm
fm from elastic electron scattering, detecting He
nuclei and electrons in coincidence with the High Resolution Spectrometers of
the Hall A Facility of Jefferson Lab. The results are in qualitative agreement
with realistic meson-nucleon theoretical calculations. The data have uncovered
a second diffraction minimum, which was predicted in the range of this
experiment, and rule out conclusively long-standing predictions of dimensional
scaling of high-energy amplitudes using quark counting.Comment: 4 pages, 2 figure
OGLE-2016-BLG-1469L: Microlensing Binary Composed of Brown Dwarfs
We report the discovery of a binary composed of two brown dwarfs, based on
the analysis of the microlensing event OGLE-2016-BLG-1469. Thanks to detection
of both finite-source and microlens-parallax effects, we are able to measure
both the masses , , and distance
kpc, as well as the projected separation au. This is the third brown-dwarf binary detected using the microlensing
method, demonstrating the usefulness of microlensing in detecting field
brown-dwarf binaries with separations less than 1 au.Comment: 8 pages, 8 figure
Limits on Light Weakly Interacting Massive Particles from the First 102.8 kg day Data of the CDEX-10 Experiment
We report the first results of a light weakly interacting massive particles
(WIMPs) search from the CDEX-10 experiment with a 10 kg germanium detector
array immersed in liquid nitrogen at the China Jinping Underground Laboratory
with a physics data size of 102.8 kg day. At an analysis threshold of 160 eVee,
improved limits of 8 and 3 cm at a
90\% confidence level on spin-independent and spin-dependent WIMP-nucleon cross
sections, respectively, at a WIMP mass () of 5 GeV/ are
achieved. The lower reach of is extended to 2 GeV/.Comment: 5 pages, 4 figure
Measurement of pretzelosity asymmetry of charged pion production in Semi-Inclusive Deep Inelastic Scattering on a polarized He target
An experiment to measure single-spin asymmetries in semi-inclusive production
of charged pions in deep-inelastic scattering on a transversely polarized
He target was performed at Jefferson Lab in the kinematic region of
and . The pretzelosity asymmetries on
He, which can be expressed as the convolution of the
transverse momentum dependent distribution functions and the Collins
fragmentation functions in the leading order, were measured for the first time.
Using the effective polarization approximation, we extracted the corresponding
neutron asymmetries from the measured He asymmetries and cross-section
ratios between the proton and He. Our results show that for both
on He and on the neutron the pretzelosity asymmetries are
consistent with zero within experimental uncertainties.Comment: 6 pages, 3 figures; enlarged the legends in Fig.3; added 3 citation
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