Laser pointer maculopathy. A new public health problem?

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Interacción entre cuencas sedimentarias intra-continentales y volcanismo monogenético de pequeño volumen: Cuencas de Argamasilla y Calzada-Moral - Región Volcánica del Campo de Calatrava, España

We study the volcaniclastic lithofacies interbedded between siliciclastic and carbonate sediments of Cenozoic-Quaternary age (8.7 Ma to 7,000 BP) in Argamasilla and Calzada-Moral basins (Central Spain). The siliciclastic and carbonate deposits correspond to fluvio-lacustrine sedimentary environments. The volcanic materials consist of primary and reworked volcaniclastic successions sourced from the Campo de Calatrava Volcanic Field. Pyroclastic deposits are related to monogenetic and small-volume volcanic centres, such as scoria cones, tuff rings and maars, corresponding to Strombolian and phreatomagmatic eruptive styles. Taking into account sedimentological constraints seven volcaniclastic lithofacies were distinguished. Type A corresponds to subaerial pyroclastic fall deposits, as is inferred by the common disorganization of the deposit, their breccia-like aspect with presence of large bombs, poor sorting and lack of tractional sedimentary structures. Types B1, B2, B3 and B4 have different volcanic sources and are interpreted to be the product of low-density (dilute) pyroclastic surges, with textural features indicative of fluctuations in flow regime. This interpretation is based on the fabric and grain size of pyroclasts, together with the size and geometry of the internal sedimentary structures. Type C represents a secondary volcanic deposit related to volcanic sediments reworked by transitional hyperconcentrated flows and dilute fluvial processes, having subsequently accumulated in braided fluvial systems. Finally, the Type D is interpreted as an intra-maar scoria/spatter cones related to the development of maars. The most important factors that determined the sedimentation in these basins were orientation of basement faults, paleogeographic and sedimentological controls, style of eruption and volcaniclastic lithofacies type.Cenozoica y Cuaternaria (8,7 Ma a 7.000 BP) en las cuencas de Argamasilla y de Calzada-Moral (centro de España). Los depósitos carbonatados y siliciclásticos corresponden a ambientes sedimentarios fluvio-lacustres. Los materiales volcánicos se componen de sucesiones primarias y retrabajadas originadas en el Campo Volcánico del Campo de Calatrava. Los depósitos piroclásticos están relacionados con centros volcánicos monogenéticos y de pequeño volumen, como conos de escoria, anillos de tobas y maars, correspondientes a erupciones estrombolianas y freatomagmáticas. Teniendo en cuenta el análisis sedimentológico se han distinguido siete litofacies volcanoclásticas. El Tipo A corresponde a depósitos de caída piroclástica subaérea, como se infiere por la desorganización común del depósito, su aspecto de breccia con presencia de grandes bombas, mala clasificación y la ausencia de estructuras sedimentarias de tracción. Los tipos B1, B2, B3 y B4 tienen diferentes fuentes volcánicas y se interpretan como productos de oleadas piroclásticas de baja densidad (diluidas), con características texturales indicativas de las fluctuaciones del régimen de flujo. Esta interpretación se basa en el tamaño de grano de los piroclastos, y el tamaño y la geometría de las estructuras sedimentarias internas. El Tipo C representa un depósito volcánico secundario relacionado con sedimentos volcánicos retrabajados por flujos hiperconcentrados de transición y procesos fluviales diluidos, habiéndose acumulado posteriormente en sistemas fluviales trenzados. Por último, el Tipo D se interpreta como un cono de escoria/salpicaduras intra-maar relacionado con el desarrollo de un maar. Los principales factores que determinaron la sedimentación en estas cuencas fueron la orientación de las fallas del basamento, los controles sedimentológicos y paleogeográficos, así como el estilo eruptivo y el tipo de litofacies volcanoclástica

Dynamical Model for the Zodiacal Cloud and Sporadic Meteors

The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving to the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer (>10^5 yr at 1 AU) than postulated in the standard collisional models (10^4 yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite (IRAS) to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5)x10^11 km^2 and 4x10^19 g, respectively, in a good agreement with previous studies. The mass input required to keep the Zodiacal Cloud (ZC) in a steady state is estimated to be 10^4-10^5 kg/s. The input is up to 10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes, and need to be supplied at a faster rate

The 8Li + 2H reaction studied in inverse kinematics at 3.15 MeV/nucleon using the REX-ISOLDE post-accelerator

The reaction 8Li + 2H has been studied in inverse kinematics at the incident energy of 3.15 MeV/nucleon, using the REX-ISOLDE post-accelerator. The reaction channels corresponding to (d,p), (d,d), and (d,t) reactions populating ground states and low-lying excited states in 7 -9Li have been identified and the related angular distributions extracted and compared with coupled-channels, distorted-wave Born approximation (DWBA), and coupled-reaction-channels calculations. For the inelastic and (d,t) channels we find that higher order effects are very important and hence one needs to go beyond the simple DWBA to extract reliable structure information from these processes.Ministerio de Ciencia e Innovación FPA2006-13807-C02-01 FPA2009-08848 FPA2009-07653 FPA2009-07387 FPA2010-17142Unión Europea RII3-EURONS 50606

High-J CO emission in the Cepheus E protostellar outflow observed with SOFIA/GREAT

We present and analyze two spectrally resolved high-J CO lines towards the molecular outflow Cep E, driven by an intermediate-mass class 0 protostar. Using the GREAT receiver on board SOFIA, we observed the CO (12--11) and (13--12) transitions (E_u ~ 430 and 500 K, respectively) towards one position in the blue lobe of this outflow, that had been known to display high-velocity molecular emission. We detect the outflow emission in both transitions, up to extremely high velocities (~ 100 km/s with respect to the systemic velocity). We divide the line profiles into three velocity ranges that each have interesting spectral features: standard, intermediate, and extremely high-velocity. One distinct bullet is detected in each of the last two. A large velocity gradient analysis for these three velocity ranges provides constraints on the kinetic temperature and volume density of the emitting gas, >~ 100 K and > ~ 10^4 cm^-3, respectively. These results are in agreement with previous ISO observations and are comparable with results obtained by Herschel for similar objects. We conclude that high-J CO lines are a good tracer of molecular bullets in protostellar outflows. Our analysis suggests that different physical conditions are at work in the intermediate velocity range compared with the standard and extremely high-velocity gas at the observed position.Comment: Accepted for publication in A&A (SOFIA/GREAT special issue

Comorbidity and osteoporotic fracture: approach through predictive modeling techniques using the OSTEOMED registry

Purpose To examine the response to anti-osteoporotic treatment, considered as incident fragility fractures after a minimum follow-up of 1 year, according to sex, age, and number of comorbidities of the patients. Methods For this retrospective observational study, data from baseline and follow-up visits on the number of comorbidities, prescribed anti-osteoporotic treatment and vertebral, humerus or hip fractures in 993 patients from the OSTEOMED registry were analyzed using logistic regression and an artificial network model. Results Logistic regression showed that the probability of reducing fractures for each anti-osteoporotic treatment consid- ered was independent of sex, age, and the number of comorbidities, increasing significantly only in males taking vitamin D (OR = 7.918), patients without comorbidities taking vitamin D (OR = 4.197) and patients with ≥ 3 comorbidities taking calcium (OR = 9.412). Logistic regression correctly classified 96% of patients (Hosmer–Lemeshow = 0.492) compared with the artificial neural network model, which correctly classified 95% of patients (AUC = 0.6). Conclusion In general, sex, age and the number of comorbidities did not influence the likelihood that a given anti-osteoporotic treatment improved the risk of incident fragility fractures after 1 year, but this appeared to increase when patients had been treated with risedronate, strontium or teriparatide. The two models used classified patients similarly, but predicted differently in terms of the probability of improvement, with logistic regression being the better fit

A combined optical/infrared spectral diagnostic analysis of the HH1 jet

Complete flux-calibrated spectra covering the spectral range from 6000 A to 2.5 um have been obtained along the HH1 jet and analysed in order to explore the potential of a combined optical/near-IR diagnostic applied to jets from young stellar objects. Important physical parameters have been derived along the jet using various diagnostic line ratios. This multi-line analysis shows, in each spatially unresolved knot, the presence of zones at different excitation conditions, as expected from the cooling layers behind a shock front. In particular, a density stratification in the jet is evident from ratios of various lines of different critical density. In particular, [FeII] lines originate in a cooling layer located at larger distances from the shock front than that generating the optical lines, where the compression is higher and the temperature is declining. The derived parameters were used to measure the mass flux along the jet, adopting different procedures, the advantages and limitations of which are discussed. dM/dt is high in the initial part of the flow but decreases by about an order of magnitude further out. Conversely, the mass flux associated with the warm molecular material is low and does not show appreciable variations along the jet. We suggest that part of the mass flux in the external regions is not revealed in optical and IR lines because it is associated with a colder atomic component, which may be traced by the far-IR [O I]63 um line. Finally, we find that the gas-phase abundance of refractory species is lower than the solar value suggesting that a significant fraction of dust grains may still be present in the jet beam.Comment: Accepted on Astronomy & Astrophysic

Search for Cold Debris Disks around M-dwarfs

Debris disks are believed to be related to planetesimals left over around stars after planet formation has ceased. The frequency of debris disks around M-dwarfs which account for 70% of the stars in the Galaxy is unknown while constrains have already been found for A- to K-type stars. We have searched for cold debris disks around 32 field M-dwarfs by conducting observations at lambda = 850 microns with the SCUBA bolometerarray camera at the JCMT and at lambda = 1.2mm with the MAMBO array at the IRAM 30-m telescopes. This is the first survey of a large sample of M-dwarfs conducted to provide statistical constraints on debris disks around this type of stars. We have detected a new debris disk around the M0.5 dwarf GJ842.2 at lambda = 850 microns, providing evidence for cold dust at large distance from this star (~ 300AU). By combining the results of our survey with the ones of Liu et al. (2004), we estimate for the first time the detection rate of cold debris disks around field M-dwarfs with ages between 20 and 200 Myr. This detection rate is 13^{+6}_{-8} % and is consistent with the detection rate of cold debris disks (9 - 23 %) around A- to K-type main sequence stars of the same age. This is an indication that cold disks may be equally prevalent across stellar spectral types.Comment: A&A accepted on 15 september 200