441 research outputs found
Symmetry Decomposition of Potentials with Channels
We discuss the symmetry decomposition of the average density of states for
the two dimensional potential and its three dimensional
generalisation . In both problems, the energetically
accessible phase space is non-compact due to the existence of infinite channels
along the axes. It is known that in two dimensions the phase space volume is
infinite in these channels thus yielding non-standard forms for the average
density of states. Here we show that the channels also result in the symmetry
decomposition having a much stronger effect than in potentials without
channels, leading to terms which are essentially leading order. We verify these
results numerically and also observe a peculiar numerical effect which we
associate with the channels. In three dimensions, the volume of phase space is
finite and the symmetry decomposition follows more closely that for generic
potentials --- however there are still non-generic effects related to some of
the group elements
Efficacy and safety of intravenous ferric carboxymaltose compared with oral iron for the treatment of iron deficiency anaemia in women after childbirth in Tanzania: a parallelgroup, open-label, randomised controlled phase 3 trial
Background: Iron deficiency anaemia is of major concern in low-income settings, especially for women of childbearing age. Oral iron substitution efficacy is limited by poor compliance and iron depletion severity. We aimed to assess the efficacy and safety of intravenous ferric carboxymaltose versus oral iron substitution following childbirth in women with iron deficiency anaemia in Tanzania. Methods: This parallel-group, open-label, randomised controlled phase 3 trial was done at Bagamoyo District Hospital and Mwananyamala Hospital, Tanzania. Eligible participants were close to delivery and had iron deficiency anaemia defined as a haemoglobin concentration of less than 110 g/L and a ferritin concentration of less than 50 μg/L measured within 14 days before childbirth. Participants were randomly assigned 1:1 to receive intravenous ferric carboxymaltose or oral iron, stratified by haemoglobin concentration and site. Intravenous ferric carboxymaltose was administered at a dose determined by the haemoglobin concentration and bodyweight (bodyweight 35 kg to <70 kg and haemoglobin ≥100 g/L: 1000 mg in one dose; bodyweight 35 kg to <70 kg and haemoglobin <100 g/L, or bodyweight ≥70 kg and haemoglobin ≥100 g/L: 1500 mg in two doses at least 7 days apart; bodyweight ≥70 kg and haemoglobin 115 g/L) at 6 weeks. Follow-up visits were at 6 weeks, and 3, 6, and 12 months. Analyses were done in the modified intention-totreat population of participants who had a 6-week haemoglobin concentration result, using logistic and linear regression models for binary and continuous outcomes, adjusted for baseline haemoglobin concentration and site. This trial is registered with ClinicalTrials.gov, NCT02541708. Findings: Between Oct 8, 2015, and March 14, 2017, 533 individuals were screened and 230 were enrolled and randomly assigned to a study group (114 to intravenous iron, 116 to oral iron). At 6 weeks, 94 (82%) participants in the intravenous iron group and 92 (79%) in the oral iron group were assessed for the primary outcome. 75 (80%) participants in the intravenous iron group and 47 (51%) in the oral iron group had normalised haemoglobin (odds ratio 4·65, 95% CI 2·33-9·27). There were two mild to moderate infusion-related adverse events; and five serious adverse events (three in the intravenous iron group, two in the oral iron group), unrelated to the study medication. Interpretation: Intravenous iron substitution with ferric carboxymaltose was safe and yielded a better haemoglobin response than oral iron. To our knowledge, this is the first study to provide evidence of the benefits and safety of intravenous iron substitution in a low-income setting
SIM PlanetQuest Key Project Precursor Observations to Detect Gas Giant Planets Around Young Stars
We present a review of precursor observing programs for the SIM PlanetQuest
Key project devoted to detecting Jupiter mass planets around young stars. In
order to ensure that the stars in the sample are free of various sources of
astrometric noise that might impede the detection of planets, we have initiated
programs to collect photometry, high contrast images, interferometric data and
radial velocities for stars in both the Northern and Southern hemispheres. We
have completed a high contrast imaging survey of target stars in Taurus and the
Pleiades and found no definitive common proper motion companions within one
arcsecond (140 AU) of the SIM targets. Our radial velocity surveys have shown
that many of the target stars in Sco-Cen are fast rotators and a few stars in
Taurus and the Pleiades may have sub-stellar companions. Interferometric data
of a few stars in Taurus show no signs of stellar or sub-stellar companions
with separations of <5 mas. The photometric survey suggests that approximately
half of the stars initially selected for this program are variable to a degree
(1 sigma>0.1 mag) that would degrade the astrometric accuracy achievable for
that star. While the precursor programs are still a work in progress, we
provide a comprehensive list of all targets ranked according to their viability
as a result of the observations taken to date. By far, the observable that
moves the most targets from the SIM-YSO program is photometric variability.Comment: Accepted for publication in Publications of the Astronomical Society
of the Pacific, 25 pages, 9 figure
The nature of the Galactic Center source IRS 13 revealed by high spatial resolution in the infrared
High spatial resolution observations in the 1 to 3.5 micron region of the
Galactic Center source known historically as IRS 13 are presented. They include
ground-based adaptive optics images in the H, Kp (2.12/0.4 micron) and L bands,
NICMOS data in filters between 1.1 and 2.2 micron, and integral field
spectroscopic data from BEAR, an Imaging FTS, in the HeI 2.06 micron and the
Br line regions. Analysis of all these data provides a completely new
picture of the main component, IRS 13E, which appears as a cluster of seven
individual stars within a projected diameter of ~0.5'' (0.02 pc). The brightest
sources, 13E1, 13E2, 13E3 (a binary), and 13E4, are all massive stars, 13E1 a
blue object, with no detected emission line while 13E2 and 13E4 are high-mass
emission line stars. 13E2 is at the WR stage and 13E4 a massive O-type star.
13E3A and B are extremely red objects, proposed as other examples of dusty WR
stars. All these sources have a common westward proper motion. 13E5, is a red
source similar to 13E3A/B. This concentration of comoving massive hot stars,
IRS 13E, is proposed as the remaining core of a massive star cluster, which
could harbor an intermediate-mass black hole (IMBH) of ~1300 M_sol. This
detection plays in favor of a scenario in which the helium stars and the other
hot stars in the central pc originate from the stripping of a massive cluster
formed several tens of pc from the center. The detection of a discrete X-ray
emission (Baganoff et al. 2003) at the IRS~13 position is examined in this
context.Comment: 14 pages, 6 figures (3 in color), LaTeX2e, accepted in A&
Caffeine and Progression of Parkinson Disease: A Deleterious Interaction With Creatine.
OBJECTIVE: Increased caffeine intake is associated with a lower risk of Parkinson disease (PD) and is neuroprotective in mouse models of PD. However, in a previous study, an exploratory analysis suggested that, in patients taking creatine, caffeine intake was associated with a faster rate of progression. In the current study, we investigated the association of caffeine with the rate of progression of PD and the interaction of this association with creatine intake.
METHODS: Data were analyzed from a large phase 3 placebo-controlled clinical study of creatine as a potentially disease-modifying agent in PD. Subjects were recruited for this study from 45 movement disorders centers across the United States and Canada. A total of 1741 subjects with PD participated in the primary clinical study, and caffeine intake data were available for 1549 of these subjects. The association of caffeine intake with rate of progression of PD as measured by the change in the total Unified Parkinson Disease Rating Scale score and the interaction of this association with creatine intake were assessed.
RESULTS: Caffeine intake was not associated with the rate of progression of PD in the main analysis, but higher caffeine intake was associated with significantly faster progression among subjects taking creatine.
CONCLUSIONS: This is the largest and longest study conducted to date that addresses the association of caffeine with the rate of progression of PD. These data indicate a potentially deleterious interaction between caffeine and creatine with respect to the rate of progression of PD
Quantum state preparation and macroscopic entanglement in gravitational-wave detectors
Long-baseline laser-interferometer gravitational-wave detectors are operating
at a factor of 10 (in amplitude) above the standard quantum limit (SQL) within
a broad frequency band. Such a low classical noise budget has already allowed
the creation of a controlled 2.7 kg macroscopic oscillator with an effective
eigenfrequency of 150 Hz and an occupation number of 200. This result, along
with the prospect for further improvements, heralds the new possibility of
experimentally probing macroscopic quantum mechanics (MQM) - quantum mechanical
behavior of objects in the realm of everyday experience - using
gravitational-wave detectors. In this paper, we provide the mathematical
foundation for the first step of a MQM experiment: the preparation of a
macroscopic test mass into a nearly minimum-Heisenberg-limited Gaussian quantum
state, which is possible if the interferometer's classical noise beats the SQL
in a broad frequency band. Our formalism, based on Wiener filtering, allows a
straightforward conversion from the classical noise budget of a laser
interferometer, in terms of noise spectra, into the strategy for quantum state
preparation, and the quality of the prepared state. Using this formalism, we
consider how Gaussian entanglement can be built among two macroscopic test
masses, and the performance of the planned Advanced LIGO interferometers in
quantum-state preparation
Searching for a Stochastic Background of Gravitational Waves with LIGO
The Laser Interferometer Gravitational-wave Observatory (LIGO) has performed
the fourth science run, S4, with significantly improved interferometer
sensitivities with respect to previous runs. Using data acquired during this
science run, we place a limit on the amplitude of a stochastic background of
gravitational waves. For a frequency independent spectrum, the new limit is
. This is currently the most sensitive
result in the frequency range 51-150 Hz, with a factor of 13 improvement over
the previous LIGO result. We discuss complementarity of the new result with
other constraints on a stochastic background of gravitational waves, and we
investigate implications of the new result for different models of this
background.Comment: 37 pages, 16 figure
Phase II study and biomarker analysis of cetuximab combined with modified FOLFOX6 in advanced gastric cancer
This prospective study was conducted with the Korean Cancer Study Group to evaluate the efficacy and safety of cetuximab combined with modified FOLFOX6 (mFOLFOX6) as first-line treatment in recurrent or metastatic gastric cancer and to identify potential predictive biomarkers. Patients received cetuximab 400 mg m−2 at week 1 and 250 mg m−2 weekly thereafter until disease progression. Oxaliplatin (100 mg m−2) and leucovorin (100 mg m−2) were administered as a 2-h infusion followed by a 46-h continuous infusion of 5-fluorouracil (2400 mg m−2) every 2 weeks for a maximum of 12 cycles. Biomarkers potentially associated with efficacy were analysed. Among 38 evaluable patients, confirmed response rate (RR) was 50.0% (95% CI 34.1–65.9). Median time-to-progression (TTP) was 5.5 months (95% CI 4.5–6.5) and overall survival (OS) 9.9 months. Eleven patients having tumour EGFR expression by immunohistochemistry with low serum EGF and TGF-α levels showed a 100% RR compared to 37.0% in the remaining 27 patients (P<0.001). Moreover, ligand level increased when disease progressed in seven out of eight patients with EGFR expression and low baseline ligand level. No patient exhibited EGFR amplification or K-ras mutations. Gastric cancer patients with EGFR expression and low ligand levels had better outcomes with cetuximab/mFOLFOX6 treatment
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