668 research outputs found
Diagnostic ability and capacity of optical coherence tomography-angiography to detect retinal and vascular changes in patients with fibromyalgia
Background. To evaluate the neuroretina and retinal vasculature of fibromyalgia (FM) patients and calculate a linear discriminant function (LDF) to improve retinal parameters’ contribution to FM diagnosis. Methods. Fifty FM patients and 232 healthy controls underwent retinal evaluation using swept-source optical coherence tomography (SS-OCT) angiography (Triton plus; Topcon) and spectral domain OCT (SD-OCT) (Spectralis; Heidelberg). The macular (m) and peripapillary (p) retinal nerve fibre layer (RNFL) and ganglion cell layer (GCL) were assessed, as was the macular vascular density. A logistic regression analysis was performed, and an LDF was calculated to evaluate OCT’s contribution to FM diagnosis. Results. With Triton OCT, the patients presented pRNFL thinning in the temporal sector (). Spectralis OCT measurements showed decreased pRNFL in patients in the following sectors: superonasal, ; nasal, ; inferonasal, ; temporal, ; and inferotemporal, . No significant differences were observed in the macular vascular plexus between patients and controls. However, vascular density in the superior sector showed a strong inverse correlation with disease duration (r = −0.978, ). The LDF calculated for Spectralis OCT yielded an area under the ROC curve of 0.968. Conclusions. FM patients present RNFL thinning observable using SS- and SD-OCT. However, these patients show similar vascular density in the macular area to healthy controls. The LDF that combines several RNFL parameters obtained using Spectralis OCT gives this device a powerful ability to differentiate between healthy individuals and individuals with FM
Inoculum sources and Preservation in Soils of Phytophthora parasitica from Cherry Tomato in Continental Crop Areas in Southeast Spain
Inoculum sources and Preservation in Soils of Phytophthora parasitica from Cherry Tomato in Continental Crop Areas in Southeast Spai
The Large Aperture GRB Observatory
The Large Aperture GRB Observatory (LAGO) is aiming at the detection of the
high energy (around 100 GeV) component of Gamma Ray Bursts, using the single
particle technique in arrays of Water Cherenkov Detectors (WCD) in high
mountain sites (Chacaltaya, Bolivia, 5300 m a.s.l., Pico Espejo, Venezuela,
4750 m a.s.l., Sierra Negra, Mexico, 4650 m a.s.l). WCD at high altitude offer
a unique possibility of detecting low gamma fluxes in the 10 GeV - 1 TeV range.
The status of the Observatory and data collected from 2007 to date will be
presented.Comment: 4 pages, proceeding of 31st ICRC 200
Water Cherenkov Detectors response to a Gamma Ray Burst in the Large Aperture GRB Observatory
In order to characterise the behaviour of Water Cherenkov Detectors (WCD)
under a sudden increase of 1 GeV - 1 TeV background photons from a Gamma Ray
Burst (GRB), simulations were conducted and compared to data acquired by the
WCD of the Large Aperture GRB Observatory (LAGO). The LAGO operates arrays of
WCD at high altitude to detect GRBs using the single particle technique. The
LAGO sensitivity to GRBs is derived from the reported simulations of the gamma
initiated particle showers in the atmosphere and the WCD response to
secondaries.Comment: 5 pages, proceeding of the 31st ICRC 200
The 2.3 GHz continuum survey of the GEM project
We present a partial-sky survey of the radio continuum at 2.3 GHz within the
scope of the Galactic Emission Mapping (GEM) project, an observational program
conceived and developed to reveal the large-scale properties of Galactic
synchrotron radiation through a set of self-consistent surveys of the radio
continuum between 408 MHz and 10 GHz. The GEM experiment uses a portable and
double-shielded 5.5-m radiotelescope in altazimuthal configuration to map
60-degree-wide declination bands from different observational sites by
circularly scanning the sky at zenithal angles of 30 deg from a constantly
rotating platform. The observations were accomplished with a total power
receiver, whose front-end High Electron Mobility Transistor (HEMT) amplifier
was matched directly to a cylindrical horn at the prime focus of the parabolic
reflector. The Moon was used to calibrate the antenna temperature scale and the
preparation of the map required direct subtraction and destriping algorithms to
remove ground contamination as the most significant source of systematic error.
We used 484 hours of total intensity observations from two locations in
Colombia and Brazil to yield 66% sky coverage from DEC = -51.73 deg to DEC =
+34.78 deg. The zero-level uncertainty of the combined survey is 103 mK with a
temperature scale error of 5% after direct correlation with the Rhodes/HartRAO
survey at 2326 MHz on a T-T plot. The sky brightness distribution into regions
of low and high emission in the GEM survey is consistent with the appearance of
a transition region as seen in the Haslam 408 MHz and WMAP K-band surveys.
Preliminary results also show that the temperature spectral index between 408
MHz and the 2.3 GHz band of the GEM survey has a weak spatial correlation with
these regions; but it steepens significantly from high to low emission regions
with respect to the WMAP K-band survey.Comment: 20 pages, 21 figures, 6 tables. Extensively revised and enlarged
version accepted for publication in Astronomy & Astrophysics. Smaller figure
Lepton Number and Lepton Flavor Violation through Color Octet States
We discuss neutrinoless double beta decay and lepton flavor violating decays
such as in the colored seesaw scenario. In this mechanism,
neutrino masses are generated at one-loop via the exchange of TeV-scale
fermionic and scalar color octets. The same particles mediate lepton number and
flavor violating processes. We show that within this framework a dominant color
octet contribution to neutrinoless double beta decay is possible without being
in conflict with constraints from lepton flavor violating processes. We
furthermore compare the "direct" color octet contribution to neutrinoless
double beta decay with the "indirect" contribution, namely the usual standard
light Majorana neutrino exchange. For degenerate color octet fermionic states
both contributions are proportional to the usual effective mass, while for
non-degenerate octet fermions this feature is not present. Depending on the
model parameters, either of the contributions can be dominant.Comment: 17 pages, 16 figure
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