Long-range transport of Saharan dust to northern Europe: The 11-16 October 2001 outbreak observed with EARLINET

The spread of mineral particles over southwestern, western, and central Europeresulting from a strong Saharan dust outbreak in October 2001 was observed at10 stations of the European Aerosol Research Lidar Network (EARLINET). For the firsttime, an optically dense desert dust plume over Europe was characterized coherentlywith high vertical resolution on a continental scale. The main layer was located abovethe boundary layer (above 1-km height above sea level (asl)) up to 3–5-km height, andtraces of dust particles reached heights of 7–8 km. The particle optical depth typicallyranged from 0.1 to 0.5 above 1-km height asl at the wavelength of 532 nm, andmaximum values close to 0.8 were found over northern Germany. The lidar observationsare in qualitative agreement with values of optical depth derived from Total OzoneMapping Spectrometer (TOMS) data. Ten-day backward trajectories clearly indicated theSahara as the source region of the particles and revealed that the dust layer observed,e.g., over Belsk, Poland, crossed the EARLINET site Aberystwyth, UK, and southernScandinavia 24–48 hours before. Lidar-derived particle depolarization ratios,backscatter- and extinction-related A ° ngstro¨m exponents, and extinction-to-backscatterratios mainly ranged from 15 to 25%, 0.5 to 0.5, and 40–80 sr, respectively, within thelofted dust plumes. A few atmospheric model calculations are presented showing the dustconcentration over Europe. The simulations were found to be consistent with thenetwork observations.

Tomato response to a high light transmission greenhouse film

Increasing greenhouse light transmission has a positive effect not only in Northern latitudes but in Mediterranean countries as well. A greenhouse, H2, with a tetrafluoroethylene copolymer 60 microns film, (Asahi Glass company, Aflex) characterised by its high light transmission and durability was compared to another greenhouse with a co-extruded film considered as a control, H1. Tomato crop response to the increase in light during winter and summer with high temperature and light was evaluated. Light transmission in H2 remained very high in spite of the observed dust accumulation and the low angle of incidence of the winter solar radiation. Transmissivity was clearly higher for H2 (81 to 83 % throughout the season) than in the control (around 63 %). The rest of the climatic parameters were similar in both greenhouses, either in the winter or in the summer evaluations. In spite of the high solar radiation in H2, the summer temperature could be maintained at the desired levels by using evaporative cooling. Accumulated tomato yield and quality was better in the H2 greenhouse (15 % more for the winter crop and 27% more for the summer crop). Fruit size was bigger in the winter crop. As an overall conclusion, the use of high light transmissive films in Mediterranean areas is very convenient for many vegetable crops. This is valid not only in winter but in summer, provided the greenhouse has good ventilation or evaporative cooling to overcome the increase in sensible heat caused by this increase in light..

Efecte de la nutrició precoç en el desenvolupament de sibilàncies

Objectiu: provar que, enfront de l’aparició de sibilàncies, l’alletament matern es comporta com a un factor protector i l’alletament artificial com a un factor inductor. Material i mètodes: assaig clínic controlat, randomitzat, a doble cec amb grup control i seguiment de 8 anys, de la submostra espanyola, en el seu 5è any de seguiment, del treball multicèntric europeu EU CHILDHOOD OBESITY PROGRAMME (QLK1-2001-00389). La població es va dividir en 3 grups: nadons alimentats amb lactància artificial amb baix contingut proteic, nadons alimentats amb lactància artificial amb alt contingut proteic i un grup control de nadons alimentats amb llet materna. Per avaluar l’aparició de sibilàncies i la seva evolució en el temps es van realitzar entrevistes als pares a mesura que la població assolia els 6 anys de vida sobre qüestions referides als 3 i als 6 anys i s’havien de realitzar entrevistes als 8 anys de vida sobre qüestions referdies a aquesta mateixa edat. Per comprovar la repercussió en la funció pulmonar i valorar la base atòpica, es tenia previst realitzar, als 8 anys, espirometria, prik test amb aeroalergens, determinació de IgE sèrica total i quantificació dels eosinòfils en sang perifèrica. S’han valorat possibles factors de confusió com antecedents familiars de malalties de base al•lèrgica, nivell socioeconòmic familiar, factors, ambient epidemiològic i s’ha estudiat altra morbiditat associada com episodis de febre, vòmits, diarrea, dermatitis atòpica, refredat de vies respiratòries altes i prescripció mèdica d’antibiòtics. Resultats: només un 20’8% van rebre alletament matern. No s’han trobat diferències estadísticament significatives entre la història d’episodis de sibilàncies i el tipus d’alletament rebut. Tampoc s’han trobat diferències estadísticament significatives entre l’alimentació rebuda i la història de dermatitis atòpica. La llet artificial es va associar, amb significació estadística, a una major prescripció d’antibiòtics i una major incidència de patir diarrees i, sense significació estadística, es va associar a un augment del risc de patir RVA. La lactància materna es va associar amb significació estadística a una menor prescripció d’antibiòtics. La presència de germans grans i un baix nivell d’educació de la mare van contribuir a augmentar la morbiditat durant el primer any de vida. El consum d’alcohol durant l’embaràs es va associar a més episodis de vòmits i el consum de tabac a més episodis de diarrea. Conclusions: l’alletament artificial no predisposa a patir més episodis de sibilàncies ni de dermatitis atòpica. La lactància materna exclusiva durant almenys 3 mesos disminueix el risc de diarrees en els primers 6 mesos de vida i retarda l’aparició d’infeccions aparentment bacterianes que requereixen tractament antibiòtic. L’alletament matern exclusiu durant un mínim de tres mesos no comporta una substancial disminució de la morbiditat durant els primers 12 mesos de vida.

The extraordinarily bright optical afterglow of GRB 991208 and its host galaxy

Observations of the extraordinarily bright optical afterglow (OA) of GRB 991208 started 2.1 d after the event. The flux decay constant of the OA in the R-band is -2.30 +/- 0.07 up to 5 d, which is very likely due to the jet effect, and after that it is followed by a much steeper decay with constant -3.2 +/- 0.2, the fastest one ever seen in a GRB OA. A negative detection in several all-sky films taken simultaneously to the event implies either a previous additional break prior to 2 d after the occurrence of the GRB (as expected from the jet effect). The existence of a second break might indicate a steepening in the electron spectrum or the superposition of two events. Once the afterglow emission vanished, contribution of a bright underlying SN is found, but the light curve is not sufficiently well sampled to rule out a dust echo explanation. Our determination of z = 0.706 indicates that GRB 991208 is at 3.7 Gpc, implying an isotropic energy release of 1.15 x 10E53 erg which may be relaxed by beaming by a factor > 100. Precise astrometry indicates that the GRB coincides within 0.2' with the host galaxy, thus given support to a massive star origin. The absolute magnitude is M_B = -18.2, well below the knee of the galaxy luminosity function and we derive a star-forming rate of 11.5 +/- 7.1 Mo/yr. The quasi-simultaneous broad-band photometric spectral energy distribution of the afterglow is determined 3.5 day after the burst (Dec 12.0) implying a cooling frequency below the optical band, i.e. supporting a jet model with p = -2.30 as the index of the power-law electron distribution.

Polymorphous Si thin films from radio frequency plasmas of SiH4 diluted in Ar: A study by transmission electron microscopy and Raman spectroscopy

In this study, we present a detailed structural characterization by means of transmission electron microscopy and Raman spectroscopy of polymorphous silicon (pm-Si:H) thin films deposited using radio-frequency dust-forming plasmas of SiH4 diluted in Ar. Square-wave modulation of the plasma and gas temperature was varied to obtain films with different nanostructures. Transmission electron microscopy and electron diffraction have shown the presence of Si crystallites of around 2 nm in the pm-Si:H films, which are related to the nanoparticles formed in the plasma gas phase coming from their different growth stages, named particle nucleation and coagulation. Raman scattering has proved the role of the film nanostructure in the crystallization process induced ¿in situ¿ by laser heating.

Stochastic semiclassical cosmological models

We consider the classical stochastic fluctuations of spacetime geometry induced by quantum fluctuations of massless nonconformal matter fields in the early Universe. To this end, we supplement the stress-energy tensor of these fields with a stochastic part, which is computed along the lines of the Feynman-Vernon and Schwinger-Keldysh techniques; the Einstein equation is therefore upgraded to a so-called Einstein-Langevin equation. We consider in some detail the conformal fluctuations of flat spacetime and the fluctuations of the scale factor in a simple cosmological model introduced by Hartle, which consists of a spatially flat isotropic cosmology driven by radiation and dust.

Rockfall induced seismic signals: case study in Montserrat, Catalonia

After a rockfall event, a usual post event survey includes qualitative volume estimation, trajectory mapping and determination of departing zones. However, quantitative measurements are not usually made. Additional relevant quantitative information could be useful in determining the spatial occurrence of rockfall events and help us in quantifying their size. Seismic measurements could be suitable for detection purposes since they are non invasive methods and are relatively inexpensive. Moreover, seismic techniques could provide important information on rockfall size and location of impacts. On 14 February 2007 the Avalanche Group of the University of Barcelona obtained the seismic data generated by an artificially triggered rockfall event at the Montserrat massif (near Barcelona, Spain) carried out in order to purge a slope. Two 3 component seismic stations were deployed in the area about 200 m from the explosion point that triggered the rockfall. Seismic signals and video images were simultaneously obtained. The initial volume of the rockfall was estimated to be 75 m3 by laser scanner data analysis. After the explosion, dozens of boulders ranging from 10¿4 to 5 m3 in volume impacted on the ground at different locations. The blocks fell down onto a terrace, 120 m below the release zone. The impact generated a small continuous mass movement composed of a mixture of rocks, sand and dust that ran down the slope and impacted on the road 60 m below. Time, time-frequency evolution and particle motion analysis of the seismic records and seismic energy estimation were performed. The results are as follows: 1 ¿ A rockfall event generates seismic signals with specific characteristics in the time domain; 2 ¿ the seismic signals generated by the mass movement show a time-frequency evolution different from that of other seismogenic sources (e.g. earthquakes, explosions or a single rock impact). This feature could be used for detection purposes; 3 ¿ particle motion plot analysis shows that the procedure to locate the rock impact using two stations is feasible; 4 ¿ The feasibility and validity of seismic methods for the detection of rockfall events, their localization and size determination are comfirmed.

Buccal dental microwear and stable isotopes of El Collado: A mesolithic site from Spain,

This study examines the correlation between buccal dental microwear and stable isotopes. The buccal surface of post-canine teeth casts from El Collado, the largest Mesolithic site in Spain, were examined under Scanning Electron Microscope; photomicrographs were taken from the middle third of the buccal surface with magnification 100X. Only six individuals passed the criteria for buccal dental microwear analysis. The photomicrographs were treated by adobe Photoshop 8.01 to cover an area 0.56 mm² of middle third of buccal surface, the output photomicrographs were digitized using Sigmascan Pro 5 by SPSS. Then the correlation between buccal microwear pattern and stable isotopes of the same individuals, of the previous study of Guixe et al., 2006, was examined using a Pearson test. Statistical analysis revealed that there is no significant correlation between stable isotopes and buccal dental microwear of the people of the Mesolithic site of El Collado. The historical and archaeological documentation suggest that the Mesolithic people tended to consume marine food. Fish-drying techniques were used during the Mesolithic period which allowed the introduction of dust and sand to the fish. These abrasive particles affected the buccal dental microwear pattern, so that no correlation between the isotopes and microwear may be expected. This also suggests that the buccal dental microwear pattern exceeds dietary reconstruction to reconstruct food processing techniques.

Buccal dental microwear and stable isotopes of El Collado: A mesolithic site from Spain,

This study examines the correlation between buccal dental microwear and stable isotopes. The buccal surface of post-canine teeth casts from El Collado, the largest Mesolithic site in Spain, were examined under Scanning Electron Microscope; photomicrographs were taken from the middle third of the buccal surface with magnification 100X. Only six individuals passed the criteria for buccal dental microwear analysis. The photomicrographs were treated by adobe Photoshop 8.01 to cover an area 0.56 mm² of middle third of buccal surface, the output photomicrographs were digitized using Sigmascan Pro 5 by SPSS. Then the correlation between buccal microwear pattern and stable isotopes of the same individuals, of the previous study of Guixe et al., 2006, was examined using a Pearson test. Statistical analysis revealed that there is no significant correlation between stable isotopes and buccal dental microwear of the people of the Mesolithic site of El Collado. The historical and archaeological documentation suggest that the Mesolithic people tended to consume marine food. Fish-drying techniques were used during the Mesolithic period which allowed the introduction of dust and sand to the fish. These abrasive particles affected the buccal dental microwear pattern, so that no correlation between the isotopes and microwear may be expected. This also suggests that the buccal dental microwear pattern exceeds dietary reconstruction to reconstruct food processing techniques.