3,944 research outputs found
Clinical implication of FMR1 intermediate alleles in a Spanish population
FMR1 premutation carriers (55-200 CGGs) are at risk of developing Fragile X-associated primary ovarian insufficiency as well as Fragile X-associated tremor/ataxia syndrome. FMR1 premutation alleles are also associated with a variety of disorders, including psychiatric, developmental, and neurological problems. However, there is a major concern regarding clinical implications of smaller CGG expansions known as intermediate alleles (IA) or gray zone alleles (45-54 CGG). Although several studies have hypothesized that IA may be involved in the etiology of FMR1 premutation associated phenotypes, this association still remains unclear. The aim of this study was to provide new data on the clinical implications of IA. We reviewed a total of 17 011 individuals: 1142 with primary ovarian insufficiency, 478 with movement disorders, 14 006 with neurodevelopmental disorders and 1385 controls. Similar IA frequencies were detected in all the cases and controls (cases 1.20% vs controls 1.39%, P =.427). When comparing the allelic frequencies of IA = 50CGGs, a greater, albeit not statistically significant, number of alleles were detected in all the cohorts of patients. Therefore, IA below 50 CGGs should not be considered as risk factors for FMR1 premutation-associated phenotypes, at least in our population. However, the clinical implication of IA = 50CGGs remains to be further elucidated
Acoustic signal detection through the cross-correlation method in experiments with different signal to noise ratio and reverberation conditions
[EN] The study and application of signal detection techniques based on
cross-correlation method for acoustic transient signals in noisy and reverberant
environments are presented. These techniques are shown to provide high signal
to noise ratio, good signal discernment from very close echoes and accurate
detection of signal arrival time. The proposed methodology has been tested on
different signal to noise ratio and reverberation conditions using real data collected
in several experiences related to acoustic systems in astroparticle detectors.
This work focuses on the acoustic detection applied to tasks of positioning
in underwater structures and calibration such those as ANTARES and KM3NeT
deep-sea neutrino telescopes, as well as, in particle detection through acoustic
events for the COUPP/PICO detectors. Moreover, a method for obtaining the
real amplitude of the signal in time (voltage) by using cross correlation has been
developed and tested and is described in this work.This work has been supported by the Ministerio de Economía y Competitividad (Spanish Government), project ref. FPA2012-37528-C02-02 and Multidark
(CSD2009-00064). It has also being funded by Generalitat Valenciana, Prometeo/2009/26, and ACOMP/2014/153. Thanks to the ANTARES Collaboration for the help in the measurements made in the ANTARES deep-sea neutrino telescope.Adrián Martínez, S.; Bou Cabo, M.; Felis, I.; Llorens Alvarez, CD.; Martínez Mora, JA.; Saldaña, M.; Ardid Ramírez, M. (2015). Acoustic signal detection through the cross-correlation method in experiments with different signal to noise ratio and reverberation conditions. Lecture Notes in Computer Science. 8629:66-79. https://doi.org/10.1007/978-3-662-46338-3_7S66798629Ageron, M., et al. (ANTARES Collaboration): ANTARES: the first undersea neutrino telescope. Nucl. Instr. Meth. A 656, 11–38 (2011)The KM3NeT Collaboration: KM3NeT technical design report (2010). ISBN 978-90-6488-033-9. www.km3net.orgBehnke, E., et al. (COUPP Collaboration): First dark matter search results from a 4-kg CF3I bubble chamber operated in a deep underground site. Phys. Rev. D 86, 052001 (2012)Ardid, M.: Positioning system of the ANTARES neutrino telescope. Nucl. Instr. Meth. A 602, 174–176 (2009)Larosa, G., Ardid, M.: KM3NeT acoustic position calibration of the KM3NeT neutrino telescope. Nucl. Instr. Meth. A 718, 502–503 (2013)Ardid, M.: ANTARES: an underwater network of sensors for neutrino astronomy and deep-sea research. Ad Hoc Sensor Wirel. Netw. 8, 21–34 (2009)Bou-Cabo, M., Ardid, M., Felis, I.: Acoustic studies for alpha background rejection in dark matter bubble chamber detectors. In: Proceedings of the IV International Workshop in Low Radioactivity Techniques. AIP Conference Proceedings, vol. 1549, pp. 142–147 (2013)Proakis, J.G., Manolakis, D.G.: Digital Signal Processing, 3rd edn. Prentice Hall, Upper Saddle River (1996)Saldaña, M.: Acoustic system development for the underwater neutrino telescope positioning KM3NeT, Bienal de Física (2013)Ardid, M., et al.: Acoustic transmitters for underwater neutrino telescopes. Sensors 12, 4113–4132 (2012)Felis, I., Bou-Cabo, M., Ardid, M.: Sistemas acústicos para la detección de Materia Oscura, Bienal de Física (2013)Llorens, C.D., et al.: The sound emission board of the KM3NeT acoustic positioning system. J. Instrum. 7, C01001 (2012)Graf, K.: Experimental studies within ANTARES towards acoustic detection of ultra high energy neutrinos in the deep sea. Ph.D. thesis, U. Erlangen, FAU-PI1-DISS-08-001 (2008
The 2HWC HAWC Observatory Gamma Ray Catalog
We present the first catalog of TeV gamma-ray sources realized with the
recently completed High Altitude Water Cherenkov Observatory (HAWC). It is the
most sensitive wide field-of-view TeV telescope currently in operation, with a
1-year survey sensitivity of ~5-10% of the flux of the Crab Nebula. With an
instantaneous field of view >1.5 sr and >90% duty cycle, it continuously
surveys and monitors the sky for gamma ray energies between hundreds GeV and
tens of TeV.
HAWC is located in Mexico at a latitude of 19 degree North and was completed
in March 2015. Here, we present the 2HWC catalog, which is the result of the
first source search realized with the complete HAWC detector. Realized with 507
days of data and represents the most sensitive TeV survey to date for such a
large fraction of the sky. A total of 39 sources were detected, with an
expected contamination of 0.5 due to background fluctuation. Out of these
sources, 16 are more than one degree away from any previously reported TeV
source. The source list, including the position measurement, spectrum
measurement, and uncertainties, is reported. Seven of the detected sources may
be associated with pulsar wind nebulae, two with supernova remnants, two with
blazars, and the remaining 23 have no firm identification yet.Comment: Submitted 2017/02/09 to the Astrophysical Journa
Constraining the Ratio in TeV Cosmic Rays with Observations of the Moon Shadow by HAWC
An indirect measurement of the antiproton flux in cosmic rays is possible as
the particles undergo deflection by the geomagnetic field. This effect can be
measured by studying the deficit in the flux, or shadow, created by the Moon as
it absorbs cosmic rays that are headed towards the Earth. The shadow is
displaced from the actual position of the Moon due to geomagnetic deflection,
which is a function of the energy and charge of the cosmic rays. The
displacement provides a natural tool for momentum/charge discrimination that
can be used to study the composition of cosmic rays. Using 33 months of data
comprising more than 80 billion cosmic rays measured by the High Altitude Water
Cherenkov (HAWC) observatory, we have analyzed the Moon shadow to search for
TeV antiprotons in cosmic rays. We present our first upper limits on the
fraction, which in the absence of any direct measurements, provide
the tightest available constraints of on the antiproton fraction for
energies between 1 and 10 TeV.Comment: 10 pages, 5 figures. Accepted by Physical Review
The Sensitivity of HAWC to High-Mass Dark Matter Annihilations
The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view
detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in
central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC
will observe gamma rays and cosmic rays with an array of water Cherenkov
detectors. The full HAWC array is scheduled to be operational in Spring 2015.
In this paper, we study the HAWC sensitivity to the gamma-ray signatures of
high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be
sensitive to diverse searches for dark matter annihilation, including
annihilation from extended dark matter sources, the diffuse gamma-ray emission
from dark matter annihilation, and gamma-ray emission from non-luminous dark
matter subhalos. Here we consider the HAWC sensitivity to a subset of these
sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the
Galactic center. We simulate the HAWC response to gamma rays from these sources
in several well-motivated dark matter annihilation channels. If no gamma-ray
excess is observed, we show the limits HAWC can place on the dark matter
cross-section from these sources. In particular, in the case of dark matter
annihilation into gauge bosons, HAWC will be able to detect a narrow range of
dark matter masses to cross-sections below thermal. HAWC should also be
sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The
constraints placed by HAWC on the dark matter cross-section from known sources
should be competitive with current limits in the mass range where HAWC has
similar sensitivity. HAWC can additionally explore higher dark matter masses
than are currently constrained.Comment: 15 pages, 4 figures, version to be published in PR
Observation of the Crab Nebula with the HAWC Gamma-Ray Observatory
The Crab Nebula is the brightest TeV gamma-ray source in the sky and has been
used for the past 25 years as a reference source in TeV astronomy, for
calibration and verification of new TeV instruments. The High Altitude Water
Cherenkov Observatory (HAWC), completed in early 2015, has been used to observe
the Crab Nebula at high significance across nearly the full spectrum of
energies to which HAWC is sensitive. HAWC is unique for its wide field-of-view,
nearly 2 sr at any instant, and its high-energy reach, up to 100 TeV. HAWC's
sensitivity improves with the gamma-ray energy. Above 1 TeV the
sensitivity is driven by the best background rejection and angular resolution
ever achieved for a wide-field ground array.
We present a time-integrated analysis of the Crab using 507 live days of HAWC
data from 2014 November to 2016 June. The spectrum of the Crab is fit to a
function of the form . The data is well-fit with values of
, , and
log when
is fixed at 7 TeV and the fit applies between 1 and 37 TeV. Study of the
systematic errors in this HAWC measurement is discussed and estimated to be
50\% in the photon flux between 1 and 37 TeV.
Confirmation of the Crab flux serves to establish the HAWC instrument's
sensitivity for surveys of the sky. The HAWC survey will exceed sensitivity of
current-generation observatories and open a new view of 2/3 of the sky above 10
TeV.Comment: Submitted 2017/01/06 to the Astrophysical Journa
Daily monitoring of TeV gamma-ray emission from Mrk 421, Mrk 501, and the Crab Nebula with HAWC
We present results from daily monitoring of gamma rays in the energy range
to TeV with the first 17 months of data from the High
Altitude Water Cherenkov (HAWC) Observatory. Its wide field of view of 2
steradians and duty cycle of % are unique features compared to other TeV
observatories that allow us to observe every source that transits over HAWC for
up to hours each sidereal day. This regular sampling yields
unprecedented light curves from unbiased measurements that are independent of
seasons or weather conditions. For the Crab Nebula as a reference source we
find no variability in the TeV band. Our main focus is the study of the TeV
blazars Markarian (Mrk) 421 and Mrk 501. A spectral fit for Mrk 421 yields a
power law index and
an exponential cut-off
TeV. For Mrk 501, we find an index and exponential cut-off TeV. The light curves for both sources show clear
variability and a Bayesian analysis is applied to identify changes between flux
states. The highest per-transit fluxes observed from Mrk 421 exceed the Crab
Nebula flux by a factor of approximately five. For Mrk 501, several transits
show fluxes in excess of three times the Crab Nebula flux. In a comparison to
lower energy gamma-ray and X-ray monitoring data with comparable sampling we
cannot identify clear counterparts for the most significant flaring features
observed by HAWC.Comment: 18 pages, 10 figures, accepted for publication in The Astrophysical
Journa
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