101 research outputs found
Localization of the spectral expansions associated with the partial differential operators
In this paper we discuss precise conditions of the summability and localization of the spectral expansions associated with various partial differential operators. In this we study the problems in the spaces of both smooth functions and singular distributions. We study spectral expansions of the distributions with the compact support and classify the distributions with the Sobolev spaces. All theorems are formulated in terms of the smoothness and degree of the regularizations
Acute Myeloblastic Leukemia and Myelodysplastic Syndrome: Azacitidine for Prophylactic and Preventive Purposes after Allogeneic Hematopoietic Stem Cell Transplantation
Aim. To evaluate the effectiveness of preventive and prophylactic post-transplantation therapy using azacitidine (5-AZA) in patients at high risk of post-transplantation relapse.
Methods. 136 patients were included in the study performed by the pairwise comparison: 68 of them received 5-AZA after allo-HSCT and 68 patients were included in the historical control group. 5-AZA was prescribed for prophylactic or preventive purposes. The results were assessed according to the OS, RR, EFS, DUM, and relapse-free and GVHR-free survival.
Results. 1-year OS was 76 % in the 5-AZA group (95% CI 60–84 %) and 44 % in the reference group (95% CI 33–55 %) (p = 0.001); 2-year OS was 63 % (95% CI 39–67 %) and 37 % (95% CI 26–48 %) (p = 0.007), respectively. The relapse rate (RR) in the 5-AZA group was 34 % (95% CI 22–46 %) during 1 year and 51 % (95% CI 38–64 %) in the reference group (p = 0.02). 1- and 2-year disease unrelated mortality (DUM) was similar: 5 % in the 5-AZA group (95% CI 0.1–14.0 %) and 25 % (95% CI 13–37 %) in the reference group (p = 0.005). 1-year EFS was 76 % in the 5-AZA group (95% CI 61–85 %) and 44 % in the reference group (95% CI 33–55 %) (p = 0.001); 2-year EFS was 63 % (95% CI 39–67 %) and 37 % (95% CI 26–48 %) (p = 0.01), respectively. 1-year relapse-free and GVHR-free survival was 55 % in the 5-AZA group (95% CI 41–69 %) and 28 % in the reference group (95% CI 17–39 %) (p = 0.001); 2-year relapse-free and GVHR-free survival was 47 % (95% CI 32–62 %) and 27 % (95% CI 17–37 %) (p = 0.002), respectively.
Conclusion. The use of 5-AZA for prophylactic and preventive purposes after allo-HSCT does not increase the risk of GVHR and DUM, does not suppress the GVL effect and can be used in combination with the donor lymphocyte infusion (DLI). The therapy with 5-AZA is safe during the early period after allo-HSCT. The drug does not suppress the GVL effect and can be used in high risk patients to prevent early post-transplantation relapse. The use of 5-AZA in combination with DLI does not increase the incidence of severe GVHR
Elevated temperature lasing from injection microdisk lasers on silicon
The combination of high operation temperatures and small diode lasers directly grown on silicon substrates is essential for their application in future photonic integrated circuits. In this letter, results are presented for quantum dot III–V-on-Si microdisk diode lasers tested at elevated temperatures. To the best of our knowledge, we have demonstrated the first uncooled microlasers with diameter of 30 µm capable of operating in the continuous wave regime at 60 °C. In the lasing regime, the emission spectra contain one very intense line with a full-width at half-maximum of 30 pm; the side mode suppression ratio reaches 18 dB. Because of self-heating, the actual temperature of the active region is close to 100 °C. Under pulsed excitation, the maximal lasing temperature is 110 °C
Search for gamma-ray emission from magnetars with the Fermi Large Area Telescope
We report on the search for 0.1-10 GeV emission from magnetars in 17 months
of Fermi Large Area Telescope (LAT) observations. No significant evidence for
gamma-ray emission from any of the currently-known magnetars is found. The most
stringent upper limits to date on their persistent emission in the Fermi-LAT
energy range are estimated between ~10^{-12}-10^{-10} erg/s/cm2, depending on
the source. We also searched for gamma-ray pulsations and possible outbursts,
also with no significant detection. The upper limits derived support the
presence of a cut-off at an energy below a few MeV in the persistent emission
of magnetars. They also show the likely need for a revision of current models
of outer gap emission from strongly magnetized pulsars, which, in some
realizations, predict detectable GeV emission from magnetars at flux levels
exceeding the upper limits identified here using the Fermi-LAT observations.Comment: ApJ Letters in press; Corresponding authors: Caliandro G. A., Hadasch
D., Rea N., Burnett
Detection of Gamma-Ray Emission from the Starburst Galaxies M82 and NGC 253 with the Large Area Telescope on Fermi
We report the detection of high-energy gamma-ray emission from two starburst
galaxies using data obtained with the Large Area Telescope on board the Fermi
Gamma-ray Space Telescope. Steady point-like emission above 200 MeV has been
detected at significance levels of 6.8 sigma and 4.8 sigma respectively, from
sources positionally coincident with locations of the starburst galaxies M82
and NGC 253. The total fluxes of the sources are consistent with gamma-ray
emission originating from the interaction of cosmic rays with local
interstellar gas and radiation fields and constitute evidence for a link
between massive star formation and gamma-ray emission in star-forming galaxies.Comment: Submitted to ApJ Letter
Fermi Gamma-ray Imaging of a Radio Galaxy
The Fermi Gamma-ray Space Telescope has detected the gamma-ray glow emanating
from the giant radio lobes of the radio galaxy Centaurus A. The resolved
gamma-ray image shows the lobes clearly separated from the central active
source. In contrast to all other active galaxies detected so far in high-energy
gamma-rays, the lobe flux constitutes a considerable portion (>1/2) of the
total source emission. The gamma-ray emission from the lobes is interpreted as
inverse Compton scattered relic radiation from the cosmic microwave background
(CMB), with additional contribution at higher energies from the
infrared-to-optical extragalactic background light (EBL). These measurements
provide gamma-ray constraints on the magnetic field and particle energy content
in radio galaxy lobes, and a promising method to probe the cosmic relic photon
fields.Comment: 27 pages, includes Supplementary Online Material; corresponding
authors: C.C. Cheung, Y. Fukazawa, J. Knodlseder, L. Stawar
Fermi Large Area Telescope observations of PSR J1836+5925
The discovery of the gamma-ray pulsar PSR J1836+5925, powering the formerly
unidentified EGRET source 3EG J1835+5918, was one of the early accomplishments
of the Fermi Large Area Telescope (LAT). Sitting 25 degrees off the Galactic
plane, PSR J1836+5925 is a 173 ms pulsar with a characteristic age of 1.8
million years, a spindown luminosity of 1.1 erg s, and a
large off-peak emission component, making it quite unusual among the known
gamma-ray pulsar population. We present an analysis of one year of LAT data,
including an updated timing solution, detailed spectral results and a long-term
light curve showing no indication of variability. No evidence for a surrounding
pulsar wind nebula is seen and the spectral characteristics of the off-peak
emission indicate it is likely magnetospheric. Analysis of recent XMM
observations of the X-ray counterpart yields a detailed characterization of its
spectrum, which, like Geminga, is consistent with that of a neutron star
showing evidence for both magnetospheric and thermal emission.Comment: Accepted to Astrophysical Journa
Precise measurements of hydrogen and helium isotopes with BESS-Polar II
A precise knowledge of cosmic-ray hydrogen and helium isotopes provides important information to better understand Galactic cosmic-ray propagation. Deuteron and helium 3 species are mainly secondary particles created by the spallation of primary proton and helium 4 particles during their propagation in the Galaxy. Secondary-to-primary ratios thus bring direct information on the average amount of material traversed by cosmic rays in the interstellar medium. The Balloon-borne Experiment with Superconducting Spectrometer BESS-Polar II flew over Antarctica for 24.5 days from December 2007 through January 2008, during the 23rd solar cycle minimum. The instrument is made of complementary particle detectors which allow to precisely measure the charge, velocity and rigidity of incident cosmic rays. It can accurately separate and precisely measure cosmic-ray hydrogen and helium isotopes between 0.2 and 1.5 GeV/nucleon. These data, which are the most precise to date, will be reported and their implications will be discussed
A change in the optical polarization associated with a gamma-ray flare in the blazar 3C 279
It is widely accepted that strong and variable radiation detected over all
accessible energy bands in a number of active galaxies arises from a
relativistic, Doppler-boosted jet pointing close to our line of sight. The size
of the emitting zone and the location of this region relative to the central
supermassive black hole are, however, poorly known, with estimates ranging from
light-hours to a light-year or more. Here we report the coincidence of a
gamma-ray flare with a dramatic change of optical polarization angle. This
provides evidence for co-spatiality of optical and gamma-ray emission regions
and indicates a highly ordered jet magnetic field. The results also require a
non-axisymmetric structure of the emission zone, implying a curved trajectory
for the emitting material within the jet, with the dissipation region located
at a considerable distance from the black hole, at about 10^5 gravitational
radii.Comment: Published in Nature issued on 18 February 2010. Corresponding
authors: Masaaki Hayashida and Greg Madejsk
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