145 research outputs found
Aerosol characterization in Northern Africa, Northeastern Atlantic, Mediterranean Basin and Middle East from direct-sun AERONET observations
We proviede an atmospheric aerosol characterization for North Africa, Northeastern Atlantic, Mediterranean and Middle East based on the analysis of quality-assured direct-sun observations of 39 stations of the AErosol RObotic NETwork (AERONET) which include at least an annual cycle within the 1994–2007 period. We extensively test and apply the recently introduced graphical method of Gobbi and co-authors to track and discriminate different aerosol types and quantify the contribution of mineral dust. The method relies on the combined analysis of the Ångström exponent (α) and its spectral curvature δα. Plotting data in these coordinates allows to infer aerosol fine mode radius (Rf) and fractional contribution (η) to total Aerosol Optical Depth (AOD) and separate AOD growth due to fine-mode aerosol humidification and/or coagulation from AOD growth due to the increase in coarse particles or cloud contamination. Our results confirm the robustness of this graphical method. Large mineral dust is found to be the most important constituent in Northern Africa and Middle East. Under specific meteorological conditions, its transport to Southern Europe is observed from spring to autumn and decreasing with latitude. We observe "pure Saharan dust" conditions to show AOD>0.7 (ranging up to 5), α1.5 and δα~−0.2 corresponding to η>70% and Rf~0.13 μm. Here, dust mixed with fine pollution aerosols shifts the observations to the region α<0.75, in which the fine mode contribution is less than 40%.Peer ReviewedPostprint (published version
A long Saharan dust event over the western Mediterrranean: Lidar, Sun photometer observations and regional dust modeling
A long Saharan dust event affected the western Mediterranean in the period 12–
28 June 2002. Dust was present mainly between 1- and 5-km height affecting most parts
of the Iberian Peninsula and reaching western/central Europe. Intensive backscatter
lidar observations over Barcelona (Spain) and Sun photometer data from two stations
(El Arenosillo, Spain, and Avignon, France) are used to evaluate different configurations
the Dust Regional Atmospheric Modeling (DREAM) system. DREAM currently operates
dust forecasts over the Mediterranean region (http://www.bsc.es/projects/earthscience/
DREAM/) considering four particle size bins while only the first two are relevant for
long-range transport analysis since their life time is larger than 12 hours. A more detailed
bin method is implemented, and two different dust distributions at sources are
compared to the operational version. Evaluations are performed at two wavelengths
(532 and 1064 nm). The dust horizontal and vertical structure simulated by DREAM shows
very good qualitative agreement when compared to SeaWIFS satellite images and lidar
height-time displays over Barcelona. When evaluating the modeled aerosol optical depth
(AOD) against Sun photometer data, significant improvements are achieved with the
use of the new detailed bin method. In general, the model underpredicts the AOD for
increasing A ° ngstro¨m exponents because of the influence of anthropogenic pollution in the
boundary layer. In fact, the modeled AOD is highly anticorrelated with the observed
A °
ngstro¨m exponents. Avignon shows higher influence of small anthropogenic aerosols
which explains the better results of the model at the wavelength of 1064 nm over this
location. The uncertainties of backscatter lidar inversions (20–30%) are in the same order
of magnitude as the differences between the model experiments. Better model results are
obtained when comparing to lidar because most of the anthropogenic effect is removed
Neutrino mean free paths in spin-polarized neutron Fermi liquids
Neutrino mean free paths in magnetized neutron matter are calculated using
the Hartree-Fock approximation with effective Skyrme and Gogny forces in the
framework of the Landau Fermi Liquid Theory. It is shown that describing
nuclear interaction with Skyrme forces and for magnetic field strengths
, the neutrino mean free paths stay almost unchanged
at intermediate densities but they largely increase at high densities when they
are compared to the field-free case results. However the description with Gogny
forces differs from the previous and mean free paths stay almonst unchanged or
decrease at densities . This different behaviour can be explained
due to the combination of common mild variation of the Landau parameters with
both types of forces and the values of the nucleon effective mass and induced
magnetization of matter under presence of a strong magnetic field as described
with the two parametrizations of the nuclear interaction.Comment: 9 pages, 3 figure
An annual assessment of air quality with the CALIOPE modeling system over Spain
The CALIOPE project, funded by the Spanish Ministry of the Environment, aims at establishing an air quality forecasting system for Spain. With this goal, CALIOPE modeling system was developed and applied with high resolution (4 km × 4 km, 1 h) using the HERMES emission model (including emissions of resuspended particles from paved roads) specifically built up for Spain. The present study provides an evaluation and the assessment of the modeling system, coupling WRF-ARW/HERMES/CMAQ/BSC-DREAM8b for a full-year simulation in 2004 over Spain. The evaluation focuses on the capability of the model to reproduce the temporal and spatial distribution of gas phase species (NO2, O3, and SO2) and particulate matter (PM10) against ground-based measurements from the Spanish air quality monitoring network. The evaluation of the modeling results on an hourly basis shows a strong dependency of the performance of the model on the type of environment (urban, suburban and rural) and the dominant emission sources (traffic, industrial, and background). The O3 chemistry is best represented in summer, when mean hourly variability and high peaks are generally well reproduced. The mean normalized error and bias meet the recommendations proposed by the United States Environmental Protection Agency (US-EPA) and the European regulations. Modeled O3 shows higher performance for urban than for rural stations, especially at traffic stations in large cities, since stations influenced by traffic emissions (i.e., high-NOx environments) are better characterized with a more pronounced daily variability. NOx/O3 chemistry is better represented under non-limited-NO2 regimes. SO2 is mainly produced from isolated point sources (power generation and transformation industries) which generate large plumes of high SO2 concentration affecting the air quality on a local to national scale where the meteorological pattern is crucial. The contribution of mineral dust from the Sahara desert through the BSC-DREAM8b model helps to satisfactorily reproduce episodic high PM10 concentration peaks at background stations. The model assessment indicates that one of the main air quality-related problems in Spain is the high level of O3. A quarter of the Iberian Peninsula shows more than 30 days exceeding the value 120 μg m−3 for the maximum 8-h O3 concentration as a consequence of the transport of O3 precursors downwind to/from the Madrid and Barcelona metropolitan areas, and industrial areas and cities in the Mediterranean coast
Assessment of Kalman filter bias-adjustment technique to improve the simulation of ground-level ozone over Spain
The CALIOPE air quality modelling system has been used to diagnose ground level O3 concentration for the year 2004, over the Iberian Peninsula. We investigate the improvement in the simulation of daily O3 maximum by the use of a post-processing such as the Kalman filter bias-adjustment technique. The Kalman filter bias-adjustment technique is a recursive algorithm to optimally estimate bias-adjustment terms from previous measurements and model results. The bias-adjustment technique improved the simulation of daily O3 maximum for the entire year and the all the stations considered over the whole domain. The corrected simulation presents improvements in statistical indicators such as correlation, root mean square error, mean bias, and gross error. After the post-processing the exceedances of O3 concentration limits, as established by the European Directive 2008/50/CE, are better reproduced and the uncertainty of the modelling system, as established by the European Directive 2008/50/CE, is reduced from 20% to 7.5%. Such uncertainty in the model results is under the established EU limit of the 50%. Significant improvements in the O3 timing and amplitude of the daily cycle are also observed after the post-processing. The systematic improvements in the O3 maximum simulations suggest that the Kalman filter post-processing method is a suitable technique to reproduce accurate estimate of ground-level O3 concentration. With this study we evince that the adjusted O3 concentrations obtained after the post-process of the results from the CALIOPE system are a reliable means for real near time O3 forecasts
How bias-correction can improve air quality forecast over Portugal
Currently three air quality modelling systems operate routinely with high-resolution over mainland Portugal for forecasting purposes, namely MM5-CHIMERE, MM5-EURAD, and CALIOPE. They each operate daily using different horizontal resolutions (10 km × 10 km, 5 km × 5 km, and 4 km × 4 km, respectively), specific physical and chemical parameterizations, and their own emission pre-processors (with a common EMEP emission database source but different spatial disaggregation methodologies). The operational BSC-DREAM8b model is coupled offline within the aforementioned air quality systems to provide the Saharan dust contribution to particulate matter. Bias-correction studies have demonstrated the benefit of using past observational data to reduce systematic model forecast errors. The present contribution aims to evaluate the application of two bias-correction techniques, the multiplicative ratio and the Kalman filter, in order to improve air quality forecasts for Portugal. Both techniques are applied to the three modelling systems over the full year of 2010. Raw and unbiased model results for the main atmospheric pollutants (O3, NO2, SO2, PM10, and PM2.5) are analysed and compared with data from 18 monitoring stations distributed within inland Portugal on an hourly basis. Statistical analysis shows that both bias-correction techniques improve the raw forecast skills (for all the modelling systems and pollutants). In the case of O3 max-8 h, correlation coefficients improve by 19-45%, from 0.56-0.81 (raw models) to 0.78-0.86 (corrected models). PM2.5 also presents significant improvements, for example correlation coefficients increase by more than 50% (with both techniques), reaching values between 0.50 and 0.64. The corrected primary pollutants NO2 and SO2 demonstrate significant relative improvements compared to O3, mostly because the original modelling system skills are lower for those species. Although the applied techniques have different mathematical formulations and complexity levels, there are comparable answers for all of the forecasting systems. Analysis performed over specific situations such as air quality episodes and cases of unvalidated or missing data reveals different behaviours of the bias-correction techniques under study. The results confirm the advantage of the application of bias-correction techniques for air quality forecasts. Both techniques can be applied routinely in operational forecast systems and they will be useful to provide accurate alerts about exceedances to the population
Aerococcus urinae: a rare pathogen in urinary tract infections, associated with patients with underlying urinary pathology
Introducción: Aerococcus urinae es un patógeno urinario poco frecuente que ha sido asociado en la bibliografía a pacientes
en la tercera edad, con patología urinaria subyacente. La mala identificación mediante pruebas bioquímicas
convencionales, su baja tasa de aislamiento y la similar morfología con otros microorganismos considerados como
flora normal en el tracto urinario, hacen de este microorganismo un gran desconocido.
El objetivo de este trabajo fue determinar la implicación clínica de Aerococcus urinae en pacientes con infección
urinaria, estudiando la relación existente descrita en la bibliografía con pacientes en la tercera edad, con patología
urinaria subyacente. Asimismo, debido a su infradiagnóstico en infección urinaria (ITU), se evaluó la utilidad de la espectrometría
de masas MALDI-TOF (Bruker) como modelo diagnóstico confiable en el laboratorio de microbiología.
Material y métodos: Se realizó un estudio prospectivo en pacientes con infección urinaria desde mayo a septiembre
de 2014. Se estudiaron los perfiles de sensibilidad a los antimicrobianos frecuentemente utilizados en infección
urinaria. Se registraron los datos clínicos más importantes de los pacientes con un recuento positivo para A. urinae.
Resultados: De las 9261 muestras de orina analizadas, 1513 muestras resultaron tener un recuento mayor a 100.000
UFC/mL. A. urinae fue aislado en 3 casos, y la identificación por MALDI-TOF fue fiable a nivel de género y especie (
score ≥ 2) , siendo contrastada mediante secuenciación ARNr 16S. Todos los pacientes que desarrollaron infección
urinaria por A. urinae, fueron pacientes en la tercera edad con una patología subyacente, siendo en todos los casos
este microorganismo resistente a trimetropim/sulfametoxazol.
Conclusiones: La implicación de A. urinae como patógeno urinario, en pacientes con patología urinaria de base, la dificultad
en su diagnóstico, y la alta tasa de resistencia de este microorganismo a trimetropim/sulfametoxazol, hacen
recomendable establecer una especial atención en los métodos diagnósticos utilizados.Introduction: Aerococcus urinae is an uncommon urinary tract pathogen that has been associated in the literature
for older patients with underlying urinary pathology. Misidentification by conventional biochemical tests, their low
rate of isolation and similar morphology to other microorganisms considered as normal flora in the urinary tract,
makes this organism a great unknown.
The aim of this investigation is to determine the implication of Aerococcus urinae as the cause of urinary tract infections,
studying the relationship described in literature in elderly patients with underlying urinary pathology.
Material and methods: A prospective study on patients with urinary infection, from May to September 2014 was
performed. Urine-cultures with a significant bacteria and suspicious of A. urinae, were identified by means of MALDI-TOF
system, and contrasted with ARNr 16S sequencing. Profiles of antimicrobial susceptibility frequently used
in urinary tract infection were studied. Clinical data for patients with positive urine cultures for A. urinae were
registered.
Result: 9261 urine samples were analyzed, 1513 samples had counts greater than 100,000 CFU / mL. A. urinae was
isolated in 3 cases, and identification by MALDI-TOF was reliable genus and species level (score ≥ 2), being proven
by sequencing 16S rRNA. All patients who developed urinary infection by A. urinae were elderly patients with underlying
pathology, and this microorganism resistant to trimethoprim / sulfamethoxazole.
Conclusions: The A. urinae overt implication as urinary pathogen, the high rate of resistance of this organism to
trimethoprim / sulfamethoxazole, and its difficulty to diagnose, urge to pay special attention to the diagnostic
methods applied
Distribución espacial y temporal de polvo mineral atmosférico en el norte de África y Oriente medio estimada a partir de la visibilidad horizontal
El polvo mineral atmosférico desempeña un papel
muy importante en la atmósfera por su interacción
con el balance radiativo y con la microfísica de
nubes. África Septentrional es la mayor fuente de
polvo mineral en el mundo. Sin embargo, carece de
sistemas de observación desde tierra adecuados y la
información desde satélite es muy limitada debido a
la alta reflectividad del suelo. Por ello, se valora la
posibilidad de usar la visibilidad horizontal
observada en las estaciones meteorológicas como
una forma indirecta de estimar el contenido de polvo
en la atmósfera al nivel de la superficie. En este
trabajo se utilizan observaciones de visibilidad para
analizar la distribución geográfica de polvo mineral
en África Septentrional y Oriente Medio, así como
su variabilidad estacional. Posteriormente, se estudia
la relación entre visibilidad y la concentración de
partículas y se halla una relación empírica entre
ambas magnitudes que es comparada con otras
relaciones similares deducidas por otros autores.Postprint (published version
Resistencia a la insulina y Enfermedad de Alzheimer prodrómica en la Comunidad de La Rioja: primeras impresiones
Trabajo presentado en la XLIII Reunión de la Sociedad de Neurología del País Vasco, celebrada en Vitoria (España), el 6 de mayo de 202
Estudio descriptivo del patrón de dieta y adherencia a la Dieta Mediterránea en pacientes con Enfermedad de Alzheimer prodrómica en La Rioja
Trabajo presentado en la Reunión Anual de la Sociedad de Neurología del País Vasco, celebrada en San Sebastián (España), los días 3 y 4 de marzo de 202
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