41 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
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
Contemporary update of SPECT tracers and novelties in radioguided surgery: a perspective based on urology
Recent technical advances and implementation of novel radiotracers have further increased the potential of radioguided surgery for a broad variety of malignancies. Indeed, the possibilities for future applications of novel radiotracers in diverse degrees neologiesl strategies has become more promising than ever. This literature review aims to provide a contemporary update on a selected group of radiotracers and evaluates the usability of radioguided surgery and sentinel node procedures, focusing on most promising advances. For example, the impact of targeted radiotracers on prostate specific membrane antigen (PSMA), CD206 receptor-targeted agents (Tc-99(m)-tilmanocept), and hybrid tracers adding fluorescence to radioguidance (ICG-Tc-99(m)-nanocolloid) as well as targeting hypoxia-induced carbonic anhydrase IX (CAIX) will be covered. Furthermore, future outlooks on the implementation of gold nanoparticles (AuNP's), but also technical advances in improved radiotracer detection by hybrid gamma devices will be discussed.Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas
Sentinel Lymph Node Biopsy for Prostate Cancer: A Hybrid Approach
Imaging- and therapeutic targets in neoplastic and musculoskeletal inflammatory diseas
New Smart Objects: How Digital Transactions Have Enabled a New Mode of Representation in Painting
The aim of the thesis is to understand how the influence of digital media has led to new ways of consuming and creating painting, enabling a new mode of representation. It is argued that a fundamental problem of contemporary art discourse is the exclusion of painting from most discussion of New Media, despite a multitude of shared conceptual and procedural approaches. The thesis first provides an overview of contemporary painting practice, presenting two dominant areas: ‘Provisional Painting’ and ‘Post-Internet Painting’. It is argued that both are insufficient to describe the complexities of painting in relation to the broader contemporary condition as influenced by digital media. The thesis then discusses fundamental aspects of digital technology, explaining how it has previously been used by artists. It is proposed that until recently the ‘digital translation’ was the dominant process in the utilisation of digital technology in painting, functioning to translate images between de-materialised and materialised form. It is also argued that artists are now engaging in a process termed the ‘digital transformation’; an action that moves beyond the digital translation as simply the intentioned alteration of image and object. The resulting alteration is termed the ‘visual artifact’. The ‘digital transaction’ is employed to describe the enacting of these processes between digital media and materialised forms, while ‘the Archive’ is used to describe the complete system of exchange through which these processes occur—incorporating the Internet and other forms of media. Five case studies of work undertaken during the research process demonstrate the process of creation and show how the aforementioned terms are applied. Finally, the thesis reflects on how this work demonstrates a new mode of painting—termed ‘New Representation’. The accompanying creative work presented for examination is a series of paintings presented at Chalk Horse Gallery in Sydney