635 research outputs found
Review of Reactor Antineutrino Experiments
As discussed elsewhere, the measurement of a non-zero value for
would open up a wide range of possibilities to explore CP-violation and the
mass hierarchy. Experimental methods to measure currently the unknown mixing
angle include accelerator searches for the appearance
and precise measurements of reactor antineutrino disappearance. The reactor
antineutrino experiments are designed to search for a non-vanishing mixing
angle with unprecedented sensitivity. This document describes
current reactor antineutrino experiments and synergy between accelerator
searches for the appearance and precise measurements of reactor
antineutrino disappearance.Comment: 8 pages, 2 figures, Review talk given at NuFact 2011, XIIIth
InternationalWorkshop on Neutrino Factories, Super beams and Beta beams,
CERN/UNIGE, Geneva, Switzerland, August 1-6, 201
Global no net loss of natural ecosystems
A global goal of no net loss of natural ecosystems or better has recently been proposed, but such a goal would require equitable translation to country-level contributions. Given the wide variation in ecosystem depletion, these could vary from net gain (for countries where restoration is needed), to managed net loss (in rare circumstances where natural ecosystems remain extensive and human development imperative is greatest). National contributions and international support for implementation also must consider non-area targets factors such as the capacity to conserve and the imperative for human development
Pleosporales
One hundred and five generic types of Pleosporales are described and illustrated. A brief introduction and detailed history with short notes on morphology, molecular phylogeny as well as a general conclusion of each genus are provided. For those genera where the type or a representative specimen is unavailable, a brief note is given. Altogether 174 genera of Pleosporales are treated. Phaeotrichaceae as well as Kriegeriella, Zeuctomorpha and Muroia are excluded from Pleosporales. Based on the multigene phylogenetic analysis, the suborder Massarineae is emended to accommodate five families, viz. Lentitheciaceae, Massarinaceae, Montagnulaceae, Morosphaeriaceae and Trematosphaeriaceae
COVID-19 severity correlates with airway epithelium-immune cell interactions identified by single-cell analysis
To investigate the immune response and mechanisms associated with severe coronavirus disease 2019 (COVID-19), we performed single-cell RNA sequencing on nasopharyngeal and bronchial samples from 19 clinically well-characterized patients with moderate or critical disease and from five healthy controls. We identified airway epithelial cell types and states vulnerable to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In patients with COVID-19, epithelial cells showed an average three-fold increase in expression of the SARS-CoV-2 entry receptor ACE2, which correlated with interferon signals by immune cells. Compared to moderate cases, critical cases exhibited stronger interactions between epithelial and immune cells, as indicated by ligand–receptor expression profiles, and activated immune cells, including inflammatory macrophages expressing CCL2, CCL3, CCL20, CXCL1, CXCL3, CXCL10, IL8, IL1B and TNF. The transcriptional differences in critical cases compared to moderate cases likely contribute to clinical observations of heightened inflammatory tissue damage, lung injury and respiratory failure. Our data suggest that pharmacologic inhibition of the CCR1 and/or CCR5 pathways might suppress immune hyperactivation in critical COVID-19
Suzaku Observations of Luminous Quasars: Revealing the Nature of High-Energy Blazar Emission in Quiescent States
We present the results from the Suzaku X-ray observations of five
flat-spectrum radio quasars (FSRQs), namely PKS0208-512, Q0827+243,
PKS1127-145, PKS1510-089 and 3C 454.3. All these sources were additionally
monitored simultaneously or quasi-simultaneously by the Fermi satellite in
gamma-rays and the Swift UVOT in the UV and optical bands, respectively. We
constructed their broad-band spectra covering the frequency range from 10^14 Hz
up to 10^25 Hz, and those reveal the nature of high-energy emission of luminous
blazars in their low-activity states. The analyzed X-ray spectra are well
fitted by a power-law model with photoelectric absorption. In the case of
PKS0208-512, PKS1127-145, and 3C 454.3, the X-ray continuum showed indication
of hard-ening at low-energies. Moreover, when compared with the previous X-ray
observations, we see a significantly increasing contribution of low-energy
photons to the total X-ray fluxes when the sources are getting fainter. The
same behavior can be noted in the Suzaku data alone. A likely explanation
involves a variable, flat-spectrum component produced via inverse-Compton (IC)
emission, plus an additional, possibly steady soft X-ray component prominent
when the source gets fainter. This soft X-ray excess is represented either by a
steep powerlaw (photon indices Gamma ~ 3 - 5) or a blackbody-type emission with
temperatures kT ~ 0.1-0.2 keV. We model the broad-band spectra spectra of the
five observed FSRQs using synchrotron self-Compton (SSC) and/or
external-Compton radiation (ECR) models. Our modeling suggests that the
difference between the low and high-activity states in luminous blazars is due
to the different total kinetic power of the jet, most likely related to varying
bulk Lorentz factor of the outflow within the blazar emission zone.Comment: 36 pages, 8 figures, 11 tables. Accepted for publication in the
Astrophysical Journal
Fermi observations of high-energy gamma-ray emission from GRB 090217A
The Fermi observatory is advancing our knowledge of Gamma-Ray Bursts (GRBs)
through pioneering observations at high energies, covering more than 7 decades
in energy with the two on-board detectors, the Large Area Telescope (LAT) and
the Gamma-ray Burst Monitor (GBM). Here we report on the observation of the
long GRB 090217A which triggered the GBM and has been detected by the LAT with
a significance greater than 9 sigma. We present the GBM and LAT observations
and on-ground analyses, including the time-resolved spectra and the study of
the temporal profile from 8 keV up to 1 GeV. All spectra are well reproduced by
a Band model. We compare these observations to the first two LAT-detected, long
bursts GRB 080825C and GRB 080916C. These bursts were found to have
time-dependent spectra and exhibited a delayed onset of the high-energy
emission, which are not observed in the case of GRB 090217A. We discuss some
theoretical implications for the high-energy emission of GRBs.Comment: 17 pages, 4 figures. Contact Authors: Fred, Piron; Sara, Cutini;
Andreas, von Kienli
Fermi observations of high-energy gamma-ray emission from GRB 080825C
The Fermi Gamma-ray Space Telescope (FGST) has opened a new high-energy
window in the study of Gamma-Ray Bursts (GRBs). Here we present a thorough
analysis of GRB 080825C, which triggered the Fermi Gamma-ray Burst Monitor
(GBM), and was the first firm detection of a GRB by the Fermi Large Area
Telescope (LAT). We discuss the LAT event selections, background estimation,
significance calculations, and localization for Fermi GRBs in general and GRB
080825C in particular. We show the results of temporal and time-resolved
spectral analysis of the GBM and LAT data. We also present some theoretical
interpretation of GRB 080825C observations as well as some common features
observed in other LAT GRBs.Comment: 18 pages, 7 figures. Accepted for publication in ApJ. Corresponding
authors: A. Bouvier, J. Granot, A.J. van der Hors
Fermi detection of delayed GeV emission from the short GRB 081024B
We report on the detailed analysis of the high-energy extended emission from
the short Gamma-Ray Burst (GRB) 081024B, detected by the Fermi Gamma-ray Space
Telescope. Historically, this represents the first clear detection of temporal
extended emission from a short GRB. The light curve observed by the Fermi
Gamma-ray Burst Monitor lasts approximately 0.8 seconds whereas the emission in
the Fermi Large Area Telescope lasts for about 3 seconds. Evidence of longer
lasting high-energy emission associated with long bursts has been already
reported by previous experiments. Our observations, together with the earlier
reported study of the bright short GRB 090510, indicate similarities in the
high-energy emission of short and long GRBs and open the path to new
interpretations.Comment: 19 pages, 4 figures, 2 tables. Accepted for publication in Ap
Indication for the disappearance of reactor electron antineutrinos in the Double Chooz experiment
The Double Chooz Experiment presents an indication of reactor electron
antineutrino disappearance consistent with neutrino oscillations. A ratio of
0.944 0.016 (stat) 0.040 (syst) observed to predicted events was
obtained in 101 days of running at the Chooz Nuclear Power Plant in France,
with two 4.25 GW reactors. The results were obtained from a single 10
m fiducial volume detector located 1050 m from the two reactor cores. The
reactor antineutrino flux prediction used the Bugey4 measurement as an anchor
point. The deficit can be interpreted as an indication of a non-zero value of
the still unmeasured neutrino mixing parameter \sang. Analyzing both the rate
of the prompt positrons and their energy spectrum we find \sang = 0.086
0.041 (stat) 0.030 (syst), or, at 90% CL, 0.015 \sang 0.16.Comment: 7 pages, 4 figures, (new version after PRL referee's comments
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