6,663 research outputs found
Extensive Air Showers and Accelerator Data - The NEEDS Workshop
Very high energy cosmic rays are typically studied by measuring extensive air
showers formed by secondary particles produced in collisions with air nuclei.
The indirect character of the measurement makes the physics interpretation of
cosmic ray data strongly dependent on simulations of multiparticle production
in showers. In April 2002 about 50 physicists met in Karlsruhe to discuss
various aspects of hadronic multiparticle production with the aim of
intensifying the interaction between high energy physics and cosmic ray groups.
Current and upcoming possibilities at accelerators for measuring features of
hadronic interactions of relevance to air showers were the focus of the
workshop. This article is a review of the discussions and conclusions.Comment: 10 pages, 11 figures, talk given at 12th ISVHECRI, Geneva, July
15-20, 200
Public Release of 2dF data from the Fornax Cluster Spectroscopic Survey
Thanks to the 2dF spectrograph on the Anglo-Australian Telescope, we have
recently completed the first stage of a complete spectroscopic survey more than
one order of magnitude larger than any previous study, measuring 7000 spectra
in a 6 sq.deg. area as part of our study of the Fornax Cluster. In this article
we describe the public release of 3600 spectra from our first field. We hope
that this public release will encourage colleagues making surveys for rare
objects to choose these fields, as much of the follow-up spectroscopy that
might be required is available from our data.Comment: To appear in the AAO Newsletter. Data online at
http://astro.ph.unimelb.edu.au/data
Human Exposure to Herpesvirus BâSeropositive Macaques, Bali, Indonesia
Herpesvirus B (Cercopithecine herpesvirus 1) has been implicated as the cause of approximately 40 cases of meningoencephalitis affecting persons in direct or indirect contact with laboratory macaques. However, the threat of herpesvirus B in nonlaboratory settings worldwide remains to be addressed. We investigated the potential for exposure to herpesvirus B in workers at a âmonkey forestâ (a temple that has become a tourist attraction because of its monkeys) in Bali, Indonesia. In July 2000, 105 workers at the Sangeh Monkey Forest in Central Bali were surveyed about contact with macaques (Macaca fascicularis). Nearly half of those interviewed had either been bitten or scratched by a macaque. Prevalence of injury was higher in those who fed macaques. Serum from 31 of 38 Sangeh macaques contained antibodies to herpesvirus B. We conclude that workers coming into contact with macaques at the Sangeh Monkey Forest are at risk for exposure to herpesvirus B
Multisensor Processing Algorithms for Underwater Dipole Localization and Tracking Using MEMS Artificial Lateral-Line Sensors
An engineered artificial lateral-line system has been recently developed, consisting of a 16-element array of finely spaced MEMS hot-wire flow sensors. This represents a new class of underwater flow sensing instruments and necessitates the development of rapid, efficient, and robust signal processing algorithms. In this paper, we report on the development and implementation of a set of algorithms that assist in the localization and tracking of vibrational dipole sources underwater. Using these algorithms, accurate tracking of the trajectory of a moving dipole source has been demonstrated successfully
Energy levels of light atoms in strong magnetic fields
In this review article we provide an overview of the field of atomic
structure of light atoms in strong magnetic fields. There is a very rich
history of this field which dates back to the very birth of quantum mechanics.
At various points in the past significant discoveries in science and technology
have repeatedly served to rejuvenate interest in atomic structure in strong
fields, broadly speaking, resulting in three eras in the development of this
field; the historical, the classical and the modern eras. The motivations for
studying atomic structure have also changed significantly as time progressed.
The review presents a chronological summary of the major advances that occurred
during these eras and discusses new insights and impetus gained. The review is
concluded with a description of the latest findings and the future prospects
for one of the most remarkably cutting-edge fields of research in science
today.Comment: 37 pages, 16 figures, 1 tabl
Unique Pattern of Enzootic Primate Viruses in Gibraltar Macaques
Because Gibraltar's macaques (Macaca sylvanus) have frequent contact with humans, we assayed 79 macaques for antibodies to enzootic primate viruses. All macaques were seronegative for herpesvirus B, simian T-cell lymphotropic virus, simian retrovirus, simian immunodeficiency virus, and rhesus cytomegalovirus. Seroprevalence of simian foamy virus reached 88% among adult animals
Inter-areal coordination of columnar architectures during visual cortical development
The occurrence of a critical period of plasticity in the visual cortex has
long been established, yet its function in normal development is not fully
understood. Here we show that as the late phase of the critical period unfolds,
different areas of cat visual cortex develop in a coordinated manner.
Orientation columns in areas V1 and V2 become matched in size in regions that
are mutually connected. The same age trend is found for such regions in the
left and right brain hemisphere. Our results indicate that a function of
critical period plasticity is to progressively coordinate the functional
architectures of different cortical areas - even across hemispheres.Comment: 30 pages, 1 table, 6 figure
Diffusion Monte Carlo calculations for the ground states of atoms and ions in neutron star magnetic fields
The diffusion quantum Monte Carlo method is extended to solve the old
theoretical physics problem of many-electron atoms and ions in intense magnetic
fields. The feature of our approach is the use of adiabatic approximation wave
functions augmented by a Jastrow factor as guiding functions to initialize the
quantum Monte Carlo prodecure. We calcula te the ground state energies of atoms
and ions with nuclear charges from Z= 2, 3, 4, ..., 26 for magnetic field
strengths relevant for neutron stars.Comment: 6 pages, 1 figure, proceedings of the "9th International Conference
on Path Integrals - New Trends and Perspectives", Max-Planck-Institut fur
Physik komplexer Systeme, Dresden, Germany, September 23 - 28, 2007, to be
published as a book by World Scientific, Singapore (2008
Population dynamics of rhesus macaques and associated foamy virus in Bangladesh.
Foamy viruses are complex retroviruses that have been shown to be transmitted from nonhuman primates to humans. In Bangladesh, infection with simian foamy virus (SFV) is ubiquitous among rhesus macaques, which come into contact with humans in diverse locations and contexts throughout the country. We analyzed microsatellite DNA from 126 macaques at six sites in Bangladesh in order to characterize geographic patterns of macaque population structure. We also included in this study 38 macaques owned by nomadic people who train them to perform for audiences. PCR was used to analyze a portion of the proviral gag gene from all SFV-positive macaques, and multiple clones were sequenced. Phylogenetic analysis was used to infer long-term patterns of viral transmission. Analyses of SFV gag gene sequences indicated that macaque populations from different areas harbor genetically distinct strains of SFV, suggesting that geographic features such as forest cover play a role in determining the dispersal of macaques and SFV. We also found evidence suggesting that humans traveling the region with performing macaques likely play a role in the translocation of macaques and SFV. Our studies found that individual animals can harbor more than one strain of SFV and that presence of more than one SFV strain is more common among older animals. Some macaques are infected with SFV that appears to be recombinant. These findings paint a more detailed picture of how geographic and sociocultural factors influence the spectrum of simian-borne retroviruses
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