311 research outputs found
Desarrollo de un servicio experimental de teledetección en los riegos del Porma (León) para el cálculo ajustado de necesidades hídricas y mejora en la gestión del regadío
El proyecto de innovación tecnológica OPTIREG Eficiencia Hídrica, impulsado por el
Grupo Tragsa, tiene entre sus objetivos principales introducir el uso de la teledetección,
como tecnología de apoyo a la gestión hídrica. Para ello se está desarrollando un servicio
web gis experimental que servirá de repositorio único de imágenes y de sus productos
derivados y que facilitará, tanto a los regantes, como a los gestores del riego, el seguimiento
de los cultivos y de sus necesidades hídricas.
Diversos estudios científicos han demostrado la buena relación lineal existente entre el
índice de vegetación normalizado (NDVI), derivado de las imágenes de satélite, y el
coeficiente de cultivo, Kc (Torres, 2010), utilizado en el cálculo de la evapotranspiración y las
necesidades hídricas. Una primera evaluación de los resultados obtenidos en la campaña
2015 para los principales cultivos en regadío en la zona de estudio del Porma (León), indica
que el Kc calculado a partir del NDVI, se ajusta mejor que el de FAO. Por ello, se considera
un sistema muy válido como referencia para ajustar no sólo la cantidad de agua, sino
también para determinar el momento más adecuado de riego, que redundará en una mayor
eficiencia hídrica
Use of a surfactant in the determination of arsenic by flow injection hydride generation atomic absorption spectrometry
Predictive model of pheochromocytoma based on the imaging features of the adrenal tumours
The purpose of our study was to develop a predictive model to rule out pheochromocytoma among adrenal tumours, based on unenhanced computed tomography (CT) and/or magnetic resonance imaging (MRI) features. We performed a retrospective multicentre study of 1131 patients presenting with adrenal lesions including 163 subjects with histological confirmation of pheochromocytoma (PHEO), and 968 patients showing no clinical suspicion of pheochromocytoma in whom plasma and/or urinary metanephrines and/or catecholamines were within reference ranges (non-PHEO). We found that tumour size was significantly larger in PHEO than non-PHEO lesions (44.3 +/- 33.2 versus 20.6 +/- 9.2 mm respectively; P < 0.001). Mean unenhanced CT attenuation was higher in PHEO (52.4 +/- 43.1 versus 4.7 +/- 17.9HU; P < 0.001). High lipid content in CT was more frequent among non-PHEO (83.6% versus 3.8% respectively; P < 0.001); and this feature alone had 83.6% sensitivity and 96.2% specificity to rule out pheochromocytoma with an area under the receiver operating characteristics curve (AUC-ROC) of 0.899. The combination of high lipid content and tumour size improved the diagnostic accuracy (AUC-ROC 0.961, sensitivity 88.1% and specificity 92.3%). The probability of having a pheochromocytoma was 0.1% for adrenal lesions smaller than 20 mm showing high lipid content in CT. Ninety percent of non-PHEO presented loss of signal in the out of phase MRI sequence compared to 39.0% of PHEO (P < 0.001), but the specificity of this feature for the diagnosis of non-PHEO lesions low. In conclusion, our study suggests that sparing biochemical screening for pheochromocytoma might be reasonable in patients with adrenal lesions smaller than 20 mm showing high lipid content in the CT scan, if there are no typical signs and symptoms of pheochromocytoma
VAMOS: a Pathfinder for the HAWC Gamma-Ray Observatory
VAMOS was a prototype detector built in 2011 at an altitude of 4100m a.s.l.
in the state of Puebla, Mexico. The aim of VAMOS was to finalize the design,
construction techniques and data acquisition system of the HAWC observatory.
HAWC is an air-shower array currently under construction at the same site of
VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water
Cherenkov detectors and two different data acquisition systems. It was in
operation between October 2011 and May 2012 with an average live time of 30%.
Besides the scientific verification purposes, the eight months of data were
used to obtain the results presented in this paper: the detector response to
the Forbush decrease of March 2012, and the analysis of possible emission, at
energies above 30 GeV, for long gamma-ray bursts GRB111016B and GRB120328B.Comment: Accepted for pubblication in Astroparticle Physics Journal (20 pages,
10 figures). Corresponding authors: A.Marinelli and D.Zaboro
Calibration of the Logarithmic-Periodic Dipole Antenna (LPDA) Radio Stations at the Pierre Auger Observatory using an Octocopter
An in-situ calibration of a logarithmic periodic dipole antenna with a
frequency coverage of 30 MHz to 80 MHz is performed. Such antennas are part of
a radio station system used for detection of cosmic ray induced air showers at
the Engineering Radio Array of the Pierre Auger Observatory, the so-called
Auger Engineering Radio Array (AERA). The directional and frequency
characteristics of the broadband antenna are investigated using a remotely
piloted aircraft (RPA) carrying a small transmitting antenna. The antenna
sensitivity is described by the vector effective length relating the measured
voltage with the electric-field components perpendicular to the incoming signal
direction. The horizontal and meridional components are determined with an
overall uncertainty of 7.4^{+0.9}_{-0.3} % and 10.3^{+2.8}_{-1.7} %
respectively. The measurement is used to correct a simulated response of the
frequency and directional response of the antenna. In addition, the influence
of the ground conductivity and permittivity on the antenna response is
simulated. Both have a negligible influence given the ground conditions
measured at the detector site. The overall uncertainties of the vector
effective length components result in an uncertainty of 8.8^{+2.1}_{-1.3} % in
the square root of the energy fluence for incoming signal directions with
zenith angles smaller than 60{\deg}.Comment: Published version. Updated online abstract only. Manuscript is
unchanged with respect to v2. 39 pages, 15 figures, 2 table
Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays detected at the Pierre Auger Observatory
We report a multi-resolution search for anisotropies in the arrival
directions of cosmic rays detected at the Pierre Auger Observatory with local
zenith angles up to and energies in excess of 4 EeV ( eV). This search is conducted by measuring the angular power spectrum
and performing a needlet wavelet analysis in two independent energy ranges.
Both analyses are complementary since the angular power spectrum achieves a
better performance in identifying large-scale patterns while the needlet
wavelet analysis, considering the parameters used in this work, presents a
higher efficiency in detecting smaller-scale anisotropies, potentially
providing directional information on any observed anisotropies. No deviation
from isotropy is observed on any angular scale in the energy range between 4
and 8 EeV. Above 8 EeV, an indication for a dipole moment is captured; while no
other deviation from isotropy is observed for moments beyond the dipole one.
The corresponding -values obtained after accounting for searches blindly
performed at several angular scales, are in the case of
the angular power spectrum, and in the case of the needlet
analysis. While these results are consistent with previous reports making use
of the same data set, they provide extensions of the previous works through the
thorough scans of the angular scales.Comment: Published version. Added journal reference and DOI. Added Report
Numbe
Ultrahigh-energy neutrino follow-up of Gravitational Wave events GW150914 and GW151226 with the Pierre Auger Observatory
On September 14, 2015 the Advanced LIGO detectors observed their first
gravitational-wave (GW) transient GW150914. This was followed by a second GW
event observed on December 26, 2015. Both events were inferred to have arisen
from the merger of black holes in binary systems. Such a system may emit
neutrinos if there are magnetic fields and disk debris remaining from the
formation of the two black holes. With the surface detector array of the Pierre
Auger Observatory we can search for neutrinos with energy above 100 PeV from
point-like sources across the sky with equatorial declination from about -65
deg. to +60 deg., and in particular from a fraction of the 90% confidence-level
(CL) inferred positions in the sky of GW150914 and GW151226. A targeted search
for highly-inclined extensive air showers, produced either by interactions of
downward-going neutrinos of all flavors in the atmosphere or by the decays of
tau leptons originating from tau-neutrino interactions in the Earth's crust
(Earth-skimming neutrinos), yielded no candidates in the Auger data collected
within s around or 1 day after the coordinated universal time (UTC)
of GW150914 and GW151226, as well as in the same search periods relative to the
UTC time of the GW candidate event LVT151012. From the non-observation we
constrain the amount of energy radiated in ultrahigh-energy neutrinos from such
remarkable events.Comment: Published version. Added journal reference and DOI. Added Report
Numbe
A search for point sources of EeV photons
Measurements of air showers made using the hybrid technique developed with
the fluorescence and surface detectors of the Pierre Auger Observatory allow a
sensitive search for point sources of EeV photons anywhere in the exposed sky.
A multivariate analysis reduces the background of hadronic cosmic rays. The
search is sensitive to a declination band from -85{\deg} to +20{\deg}, in an
energy range from 10^17.3 eV to 10^18.5 eV. No photon point source has been
detected. An upper limit on the photon flux has been derived for every
direction. The mean value of the energy flux limit that results from this,
assuming a photon spectral index of -2, is 0.06 eV cm^-2 s^-1, and no celestial
direction exceeds 0.25 eV cm^-2 s^-1. These upper limits constrain scenarios in
which EeV cosmic ray protons are emitted by non-transient sources in the
Galaxy.Comment: 28 pages, 10 figures, accepted for publication in The Astrophysical
Journa
Prevalence of diabetes mellitus and impaired glucose regulation in Spain: the [email protected] Study
Introduction: atherosclerosis, blood vessel disease, is the main cause of cardiovascular disease associated with aging; comprising modifiable risk factors that increase because of this when it exists.Objective: to evaluate atherogenic markers and metabolic syndrome in older adults, with cardiovascular risk living in urban areas, Pinar del Río province. Methods: observational, descriptive and cross-sectional study, from the service of Clinical Laboratory at Abel Santamaría Cuadrado Teaching General Hospital Pinar del Río with 60 years old and older patients from the urban areas, during the period 2013 - 2014. The target group included 588 patients. The sample comprised 100 patients who have at least two risk factors previously established for this study.Results: ample predominance of women (61.0 %), the risk factors of higher incidence were hypertension 67 %, and sedentary lifestyle 65 %, followed by obesity 48 %, diabetes mellitus 40 % along with smoking habit 32 %, obese with increased diameters of waist circumference 48 %, and dyslipidemia 49 %, those with high glycemic values in fasting 50 % of the sample. It was considered that 63 % of the patients studied suffer from metabolic syndrome.Conclusions: a high number of white-skin women, the predominant risk factors were hypertension followed by sedentary lifestyle, obesity, diabetes mellitus and smoking habit. Approximately half of the sample was obese with increased diameters of the waist circumference, a large part suffered from dyslipidemia and half of them showed high fasting blood glucose levels. The prevalence of metabolic syndrome was detected.IIntroducción: aterosclerosis, enfermedad de los vasos sanguíneos, principal causa de enfermedad cardiovascular vinculada al envejecimiento, con factores de riesgo modificables que se incrementan cuando esta existe.Objetivo: evaluar marcadores aterogénicos y síndrome metabólico en adultos mayores, con riesgo cardiovascular residentes en zonas urbanas de la provincia Pinar del Río.Métodos: estudio observacional, descriptivo, transversal, servicio de Laboratorio Clínico Hospital General Docente “Abel Santamaría Cuadrado” Pinar del Río, pacientes de 60 años y más de zonas urbanas, durante período 2013 - 2014. Universo de 588 pacientes. Muestra de 100 pacientes que posean mínimo de dos factores de riesgo establecidos con anterioridad para este estudio.Resultados: amplio predominio de las mujeres (61 %). Factores de riesgo de mayor incidencia hipertensión arterial 67 %, y sedentarismo 65 %, seguidos por obesidad 48 %, diabetes mellitus 40 % y hábito de fumar 32 %, obesos con diámetros aumentados de la circunferencia de la cintura 48 %, presentaban dislipidemia 49 % y tenían elevados valores de glucemia en ayunas el 50 % de la muestra. Se consideró que 63 % de los pacientes estudiados presentaron síndrome metabólico.Conclusiones: elevado número de mujeres de piel blanca, con factor de riesgo predominante de hipertensión arterial seguido por sedentarismo, obesidad, diabetes mellitus y hábito de fumar. Alrededor de la mitad de la muestra fueron obesos con diámetros aumentados de la circunferencia de la cintura, gran parte presentaban dislipidemia y la mitad altos valores de glucemia en ayunas. Se detecta prevalencia de síndrome metabólico
Reconstruction of inclined air showers detected with the Pierre Auger Observatory
We describe the method devised to reconstruct inclined cosmic-ray air showers
with zenith angles greater than detected with the surface array of
the Pierre Auger Observatory. The measured signals at the ground level are
fitted to muon density distributions predicted with atmospheric cascade models
to obtain the relative shower size as an overall normalization parameter. The
method is evaluated using simulated showers to test its performance. The energy
of the cosmic rays is calibrated using a sub-sample of events reconstructed
with both the fluorescence and surface array techniques. The reconstruction
method described here provides the basis of complementary analyses including an
independent measurement of the energy spectrum of ultra-high energy cosmic rays
using very inclined events collected by the Pierre Auger Observatory.Comment: 27 pages, 19 figures, accepted for publication in Journal of
Cosmology and Astroparticle Physics (JCAP
- …