71 research outputs found
Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter
Data collected by the Pierre Auger Observatory through 31 August 2007 showed
evidence for anisotropy in the arrival directions of cosmic rays above the
Greisen-Zatsepin-Kuz'min energy threshold, \nobreak{eV}. The
anisotropy was measured by the fraction of arrival directions that are less
than from the position of an active galactic nucleus within 75 Mpc
(using the V\'eron-Cetty and V\'eron catalog). An updated
measurement of this fraction is reported here using the arrival directions of
cosmic rays recorded above the same energy threshold through 31 December 2009.
The number of arrival directions has increased from 27 to 69, allowing a more
precise measurement. The correlating fraction is , compared
with expected for isotropic cosmic rays. This is down from the early
estimate of . The enlarged set of arrival directions is
examined also in relation to other populations of nearby extragalactic objects:
galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in
hard X-rays by the Swift Burst Alert Telescope. A celestial region around the
position of the radiogalaxy Cen A has the largest excess of arrival directions
relative to isotropic expectations. The 2-point autocorrelation function is
shown for the enlarged set of arrival directions and compared to the isotropic
expectation.Comment: Accepted for publication in Astroparticle Physics on 31 August 201
The Fluorescence Detector of the Pierre Auger Observatory
The Pierre Auger Observatory is a hybrid detector for ultra-high energy
cosmic rays. It combines a surface array to measure secondary particles at
ground level together with a fluorescence detector to measure the development
of air showers in the atmosphere above the array. The fluorescence detector
comprises 24 large telescopes specialized for measuring the nitrogen
fluorescence caused by charged particles of cosmic ray air showers. In this
paper we describe the components of the fluorescence detector including its
optical system, the design of the camera, the electronics, and the systems for
relative and absolute calibration. We also discuss the operation and the
monitoring of the detector. Finally, we evaluate the detector performance and
precision of shower reconstructions.Comment: 53 pages. Submitted to Nuclear Instruments and Methods in Physics
Research Section
Advanced functionality for radio analysis in the Offline software framework of the Pierre Auger Observatory
The advent of the Auger Engineering Radio Array (AERA) necessitates the
development of a powerful framework for the analysis of radio measurements of
cosmic ray air showers. As AERA performs "radio-hybrid" measurements of air
shower radio emission in coincidence with the surface particle detectors and
fluorescence telescopes of the Pierre Auger Observatory, the radio analysis
functionality had to be incorporated in the existing hybrid analysis solutions
for fluoresence and surface detector data. This goal has been achieved in a
natural way by extending the existing Auger Offline software framework with
radio functionality. In this article, we lay out the design, highlights and
features of the radio extension implemented in the Auger Offline framework. Its
functionality has achieved a high degree of sophistication and offers advanced
features such as vectorial reconstruction of the electric field, advanced
signal processing algorithms, a transparent and efficient handling of FFTs, a
very detailed simulation of detector effects, and the read-in of multiple data
formats including data from various radio simulation codes. The source code of
this radio functionality can be made available to interested parties on
request.Comment: accepted for publication in NIM A, 13 pages, minor corrections to
author list and references in v
Search for First Harmonic Modulation in the Right Ascension Distribution of Cosmic Rays Detected at the Pierre Auger Observatory
We present the results of searches for dipolar-type anisotropies in different
energy ranges above eV with the surface detector array of
the Pierre Auger Observatory, reporting on both the phase and the amplitude
measurements of the first harmonic modulation in the right-ascension
distribution. Upper limits on the amplitudes are obtained, which provide the
most stringent bounds at present, being below 2% at 99% for EeV
energies. We also compare our results to those of previous experiments as well
as with some theoretical expectations.Comment: 28 pages, 11 figure
Design of an allosterically modulated doxycycline and doxorubicin drug binding protein
Significance
The design of binding sites for nonnatural ligands into natural proteins is a very topical subject in protein design. This also applies to the manipulation of allosteric coupling pathways with the goal of controlling protein function. Here it is shown that both topics can be addressed concurrently in a single protein. Thus, starting from human α1-antichymotrypsin, two drug-binding proteins were developed. Whereas ligand-binding design enables the binding of either the antibiotic doxycycline or the anticancer compound doxorubicin, the reengineering of an existing allosteric coupling mechanism enables the release of the bound ligands on occurrence of a proteinase trigger signal. It is proposed that such binding proteins can be further developed into drug-specific delivery shuttles.</jats:p
Intercomparison of four different in-situ techniques for ambient formaldehyde measurements in an urban air
The cachexia associated with Trypanosoma cruzi acute infection in mice is attenuated by anti-TNF-a, but not by anti-IL-6 or anti-IFN-7 antibodies
BALB/c male mice acutely infected with Trypanosoma cruzi underwent a severe weight loss (around 20%, from day 18 to 31 post-infection), when compared to age-matched uninfected animals. Though mice regained weight later, when blood parasites were hardly detectable, wasting extended over the chronic phase of infection. The onset and the magnitude of weight loss were related to the mouse susceptibility to infection, since they were respectively earlier and higher in male mice which will die than in surviving ones, in males than in females, and in BALB/c than in B6D2 [(C57B1/6 x DBA/2)F1], a mouse strain more resistant to infection. Fat weight of infected mice (male BALB/c) was reduced by 60 to 80%, whereas lean mass was unaffected and water content rose by 6 to 10% in acute and chronic infection. Haematocrit was also decreased by 15-16% in acute infection. Animals failed to compensate their energetic loss since their food intake remained similar to that of uninfected animals. Injections of neutralizing anti-TNF-alpha monoclonal antibody into infected male mice, during the first two weeks but not later in infection, significantly attenuated the weight loss. Early administration of anti-IL-6 or anti-IFN-gamma MoAbs did not improve the mouse wasting. Taken together, these data show that TNF is a key agent of cachexia occurring in the acute T. cruzi infection in mice.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jFLWNAinfo:eu-repo/semantics/publishe
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