153 research outputs found
Increasing the Fine Structure Visibility of the Hinode SOT Ca II H Filtergrams
We present the improved so-called Madmax (OMC) operator selecting maxima of
convexities computed in multiple directions around each pixel rewritten in
MatLab and shown to be very efficient for pattern recognition.
The aim of the algorithm is to trace the bright hair-like features (for ex.
chromospheric thin jets or spicules) of solar ultimate observations polluted by
a noise of different origins. This popular spatial operator uses the second
derivative in the optimally selected direction for which its absolute value has
a maximum value. Accordingly, it uses the positivity of the resulting intensity
signal affected by a superposed noise. The results are illustrated using a test
artificially generated image and real SOT (Hinode) images are also used, to
make your own choice of the sensitive parameters to use in improving the
visibility of images.Comment: 12 pages, 3 figurs, submitted in Solar Physic
Measurements of the \gamma * p --> \Delta(1232) reaction at low Q2
We report new p measurements in the
resonance at the low momentum transfer region utilizing the
magnetic spectrometers of the A1 Collaboration at MAMI. The mesonic cloud
dynamics are predicted to be dominant and appreciably changing in this region
while the momentum transfer is sufficiently low to be able to test chiral
effective calculations. The results disagree with predictions of constituent
quark models and are in reasonable agreement with dynamical calculations with
pion cloud effects, chiral effective field theory and lattice calculations. The
reported measurements suggest that improvement is required to the theoretical
calculations and provide valuable input that will allow their refinements
Lowest Q^2 Measurement of the gamma*p -> Delta Reaction: Probing the Pionic Contribution
To determine nonspherical angular momentum amplitudes in hadrons at long
ranges (low Q^2), data were taken for the p(\vec{e},e'p)\pi^0 reaction in the
Delta region at Q^2=0.060 (GeV/c)^2 utilizing the magnetic spectrometers of the
A1 Collaboration at MAMI. The results for the dominant transition magnetic
dipole amplitude and the quadrupole to dipole ratios at W=1232 MeV are:
M_{1+}^{3/2} = (40.33 +/- 0.63_{stat+syst} +/- 0.61_{model})
(10^{-3}/m_{\pi^+}),Re(E_{1+}^{3/2}/M_{1+}^{3/2}) = (-2.28 +/- 0.29_{stat+syst}
+/- 0.20_{model})%, and Re(S_{1+}^{3/2}/M_{1+}^{3/2}) = (-4.81 +/-
0.27_{stat+syst} +/- 0.26_{model})%. These disagree with predictions of
constituent quark models but are in reasonable agreement with lattice
calculations with non-linear (chiral) pion mass extrapolations, with chiral
effective field theory, and with dynamical models with pion cloud effects.
These results confirm the dominance, and general Q^2 variation, of the pionic
contribution at large distances.Comment: 6 pages, 3 figures, 1 tabl
Relativistic O VIII Emission and Ionized Outflow in NGC 4051
We present XMM-Newton RGS observations of the soft X-ray spectrum of NGC
4051, and explore their implications for the inner accretion disk and ionized
outflow in the active galactic nucleus. We fit the soft X-ray excess with a
relativistically broadened O VIII recombination spectrum, including the entire
line series and recombination continuum. This plus an underlying power law
continuum provides a much better fit to the soft X-ray spectrum than a single
temperature or disk blackbody plus power law. The emission line profiles,
computed for a Kerr metric around a maximally rotating black hole, reveal a
sharply peaked disk emissivity law and inner radius smaller than 1.7 R_G. The
spectrum also includes narrow absorption and emission lines from C, N, O, Ne,
and Fe in an ionized outflow. Outflow column densities are relatively low and
do not create significant edges in the spectrum. The small amount of absorption
bolsters confidence in the detection of relativistic emission line features.
The narrow-line emitter has a large (76%) global covering fraction, leading to
strong forbidden lines and filling in of the resonance absorption lines. We
also find broad C VI Ly-alpha and very broad O VII emission from the broad-line
region. The narrow and broad-line regions span large ranges in ionization
parameter, and may arise in a disk outflow. The ionized absorber has a large
ionization range which is inconsistent with pressure equilibrium in a
multiphase medium. The mass outflow rate exceeds the accretion rate by a factor
of one thousand.Comment: 43 pages, 12 figures, Accepted for publication in the Astrophysical
Journa
Brain natriuretic peptide precursor (NT-pro-BNP) levels predict for clinical benefit to sunitinib treatment in patients with metastatic renal cell carcinoma
<p>Abstract</p> <p>Background</p> <p>Sunitinib is an oral, multitargeted tyrosine kinase inhibitor that has been approved for the treatment of metastatic renal cell carcinoma. Although the majority of sunitinib-treated patients receive a clinical benefit, almost a third of the patients will not respond. Currently there is no available marker that can predict for response in these patients.</p> <p>Methods</p> <p>We estimated the plasma levels of NT-pro-BNP (the N-terminal precursor of brain natriuretic peptide) in 36 patients that were treated with sunitinib for metastatic clear-cell renal carcinoma.</p> <p>Results</p> <p>From the 36 patients, 9 had progressive disease and 27 obtained a clinical benefit (objective response or disease stabilization). Increases in plasma NT-pro-BNP were strongly correlated to clinical outcome. Patients with disease progression increased plasma BNP at statistically significant higher levels than patients that obtained a clinical benefit, and this was evident from the first 15 days of treatment (a three-fold increase in patients with progressive disease compared to stable NT-pro-BNP levels in patients with clinical benefit, p < 0.0001). Median progression-free survival was 12.0 months in patients with less than 1.5 fold increases (n = 22) and 3.9 months in patients with more than 1.5 fold increases in plasma NT-pro-BNP (n = 13) (log-rank test, p = 0.001).</p> <p>Conclusions</p> <p>This is the first time that a potential "surrogate marker" has been reported with such a clear correlation to clinical benefit at an early time of treatment. Due to the relative small number of accessed patients, this observation needs to be further addressed on larger cohorts. More analyses, including multivariate analyses are needed before such an observation can be used in clinical practice.</p
A randomized, phase III trial to evaluate rucaparib monotherapy as maintenance treatment in patients with newly diagnosed ovarian cancer (ATHENA–MONO/GOG-3020/ENGOT-ov45)
PURPOSE: ATHENA (ClinicalTrials.gov identifier: NCT03522246) was designed to evaluate rucaparib first-line maintenance treatment in a broad patient population, including those without BRCA1 or BRCA2 (BRCA) mutations or other evidence of homologous recombination deficiency (HRD), or high-risk clinical characteristics such as residual disease. We report the results from the ATHENA–MONO comparison of rucaparib versus placebo. METHODS: Patients with stage III-IV high-grade ovarian cancer undergoing surgical cytoreduction (R0/complete resection permitted) and responding to first-line platinum-doublet chemotherapy were randomly assigned 4:1 to oral rucaparib 600 mg twice a day or placebo. Stratification factors were HRD test status, residual disease after chemotherapy, and timing of surgery. The primary end point of investigator-assessed progression-free survival was assessed in a step-down procedure, first in the HRD population (BRCA-mutant or BRCA wild-type/loss of heterozygosity high tumor), and then in the intent-to-treat population. RESULTS: As of March 23, 2022 (data cutoff), 427 and 111 patients were randomly assigned to rucaparib or placebo, respectively (HRD population: 185 v 49). Median progression-free survival (95% CI) was 28.7 months (23.0 to not reached) with rucaparib versus 11.3 months (9.1 to 22.1) with placebo in the HRD population (log-rank P = .0004; hazard ratio [HR], 0.47; 95% CI, 0.31 to 0.72); 20.2 months (15.2 to 24.7) versus 9.2 months (8.3 to 12.2) in the intent-to-treat population (log-rank P < .0001; HR, 0.52; 95% CI, 0.40 to 0.68); and 12.1 months (11.1 to 17.7) versus 9.1 months (4.0 to 12.2) in the HRD-negative population (HR, 0.65; 95% CI, 0.45 to 0.95). The most common grade ≥ 3 treatment-emergent adverse events were anemia (rucaparib, 28.7% v placebo, 0%) and neutropenia (14.6% v 0.9%). CONCLUSION: Rucaparib monotherapy is effective as first-line maintenance, conferring significant benefit versus placebo in patients with advanced ovarian cancer with and without HRD
Measurements of the γ∗p→Δ reaction at low Q2: Probing the mesonic contribution
The determination of nonspherical angular momentum amplitudes in nucleons at long ranges (low Q2) was accomplished through the p(, e'p)0 reaction in the region at Q2=0.060, 0.127, and 0.200 (GeV/c)2 at the Mainz Microtron with an accuracy for the cross sections of 4%. The results for the dominant transition magnetic dipole amplitude and the quadrupole to dipole ratios have been obtained with an estimated model uncertainty that is approximately the same as the experimental uncertainty. Lattice and effective field theory predictions agree with our data within the relatively large estimated theoretical uncertainties. Phenomenological models are in good agreement with experiment when the resonant amplitudes are adjusted to the data. To check reaction model calculations additional data were taken for center-of-mass energies below resonance and for the LT' structure function. These results confirm the dominance, and general Q2 variation, of the pionic contribution at large distances
Virtual Compton Scattering measurements in the transition
We report on new H measurements in the
resonance at (GeV/c) carried out simultaneously with H. It is the lowest for which the virtual Compton scattering (VCS)
reaction has been studied in the first resonance region. The VCS measured cross
sections are well described by dispersion-relation calculations in which the
multipole amplitudes derived from H data are used as
input, thus confirming the compatibility of the results. The derived resonant
magnetic dipole amplitude at 1232 MeV is in excellent agreement
with the value extracted from H measurements.Comment: 4 pages, 4 figure
Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results
The chromosphere is a thin layer of the solar atmosphere that bridges the
relatively cool photosphere and the intensely heated transition region and
corona. Compressible and incompressible waves propagating through the
chromosphere can supply significant amounts of energy to the interface region
and corona. In recent years an abundance of high-resolution observations from
state-of-the-art facilities have provided new and exciting ways of
disentangling the characteristics of oscillatory phenomena propagating through
the dynamic chromosphere. Coupled with rapid advancements in
magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly
investigate the role waves play in supplying energy to sustain chromospheric
and coronal heating. Here, we review the recent progress made in
characterising, categorising and interpreting oscillations manifesting in the
solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review
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