207 research outputs found
The TIANSHAN Radio Experiment for Neutrino Detection
An antenna array devoted to the autonomous radio-detection of high energy
cosmic rays is being deployed on the site of the 21 cm array radio telescope in
XinJiang, China. Thanks in particular to the very good electromagnetic
environment of this remote experimental site, self-triggering on extensive air
showers induced by cosmic rays has been achieved with a small scale prototype
of the foreseen antenna array. We give here a detailed description of the
detector and present the first detection of extensive air showers with this
prototype.Comment: 37 pages, 15 figures. Astroparticle Physics (in press
Radioelectric Field Features of Extensive Air Showers Observed with CODALEMA
Based on a new approach to the detection of radio transients associated with
extensive air showers induced by ultra high energy cosmic rays, the
experimental apparatus CODALEMA is in operation, measuring about 1 event per
day corresponding to an energy threshold ~ 5. 10^16 eV. Its performance makes
possible for the first time the study of radio-signal features on an
event-by-event basis. The sampling of the magnitude of the electric field along
a 600 meters axis is analyzed. It shows that the electric field lateral spread
is around 250 m (FWHM). The possibility to determine with radio both arrival
directions and shower core positions is discussed.Comment: Accepted for publication in Astroparticle Physic
Five-year follow-up of bilateral stimulation of the subthalamic nucleus in advanced Parkinson's disease
Background: Although the short-term benefits of bilateral stimulation of the subthalamic nucleus in patients with advanced Parkinson's disease have been well documented, the long-term outcomes of the procedure are unknown.
Methods: We conducted a five-year prospective study of the first 49 consecutive patients whom we treated with bilateral stimulation of the subthalamic nucleus. Patients were assessed at one, three, and five years with levodopa (on medication) and without levodopa (off medication), with use of the Unified Parkinson's Disease Rating Scale. Seven patients did not complete the study: three died, and four were lost to follow-up.
Results: As compared with base line, the patients' scores at five years for motor function while off medication improved by 54 percent (P<0.001) and those for activities of daily living improved by 49 percent (P<0.001). Speech was the only motor function for which off-medication scores did not improve. The scores for motor function on medication did not improve one year after surgery, except for the dyskinesia scores. On-medication akinesia, speech, postural stability, and freezing of gait worsened between year 1 and year 5 (P<0.001 for all comparisons). At five years, the dose of dopaminergic treatment and the duration and severity of levodopa-induced dyskinesia were reduced, as compared with base line (P<0.001 for each comparison). The average scores for cognitive performance remained unchanged, but dementia developed in three patients after three years. Mean depression scores remained unchanged. Severe adverse events included a large intracerebral hemorrhage in one patient. One patient committed suicide.
Conclusions: Patients with advanced Parkinson's disease who were treated with bilateral stimulation of the subthalamic nucleus had marked improvements over five years in motor function while off medication and in dyskinesia while on medication. There was no control group, but worsening of akinesia, speech, postural stability, freezing of gait, and cognitive function between the first and the fifth year is consistent with the natural history of Parkinson's disease
Radio Detection of Cosmic Ray Air Showers with Codalema
Studies of the radio detection of Extensive Air Showers is the goal of the
demonstrative experiment CODALEMA. Previous analysis have demonstrated that
detection around eV was achieved with this set-up. New results
allow for the first time to study the topology of the electric field associated
to EAS events on a event by event basis.Comment: 6 pages, 4 figures Proceedings of the Rencontres de Moriond, Very
High Energy Phenomena in the Universe, La Thuile, Italy (March 12-19, 2005
Radio Detection of Extensive Air Showers with CODALEMA
The principle and performances of the CODALEMA experimental device, set up to
study the possibility of high energy cosmic rays radio detection, are
presented. Radio transient signals associated to cosmic rays have been
identified, for which arrival directions and shower's electric field topologies
have been extracted from the antenna signals. The measured rate, about 1 event
per day, corresponds to an energy threshold around 5.10^16 eV. These results
allow to determine the perspectives offered by the present experimental design
for radiodetection of UHECR at a larger scale.Comment: 4 pages and 3 figures. To appear in the Proceedings of the 29th ICRC,
Pune (2005
Effect of hard processes on momentum correlations in and collisions
The HBT radii extracted in p-pbar and pp collisions at SPS and Tevatron show
a clear correlation with the charged particle rapidity density. We propose to
explain the correlation using a simple model where the distance from the
initial hard parton-parton scattering to the hadronization point depends on the
energy of the partons emitted. Since the particle multiplicity is correlated
with the mean energy of the partons produced we can explain the experimental
observations without invoking scenarios that assume a thermal fireball. The
model has been applied with success to the existing experimental data both in
the magnitude and the intensity of the correlation. As well, the model has been
extended to pp collisions at the LHC energy of 14 TeV. The possibilities of a
better insight into the string spatial development using 3D HBT analysis is
discussed.Comment: 12 pages, 6 figure
Radiodetection of Cosmic Ray Extensive Air Showers
We present the characteristics and performance of a demonstration experiment
devoted to the observation of ultra high- energy cosmic ray extensive air
showers using a radiodetection technique. In a first step, one antenna narrowed
band filtered acting as trigger, with a 4 threshold above sky
background-level, was used to tag any radio transient in coincidence on the
antenna array. Recently, the addition of 4 particle detectors has allowed us to
observe cosmic ray events in coincidence with antennas
Radio Detection of Cosmic Ray Extensive Air Showers: present status of the CODALEMA experiment
Data acquisition and analysis for the CODALEMA experiment, in operation for
more than one year, has provided improved knowledge of the characteristics of
this new device. At the same time, an important effort has been made to develop
processing techniques for extracting transient signals from data containing
interference.Comment: september 200
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