Prehistoria : guía didáctica

En cub.: Museo de Valladolid

Airborne in situ vertical profiling of HDO/H₂¹⁶O in the subtropical troposphere during the MUSICA remote sensing validation campaign

Vertical profiles of water vapor (H2O) and its isotope ratio D/H expressed as δD(H2O) were measured in situ by the ISOWAT II diode-laser spectrometer during the MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA) airborne campaign. We present recent modifications of the instrument design. The instrument calibration on the ground as well as in flight is described. Based on the calibration measurements, the humidity-dependent uncertainty of our airborne data is determined. For the majority of the airborne data we achieved an accuracy (uncertainty of the mean) of δ(δD) ≈10‰. Vertical profiles between 150 and ∼7000 m were obtained during 7 days in July and August 2013 over the subtropical North Atlantic Ocean near Tenerife. The flights were coordinated with ground-based (Network for the Detection of Atmospheric Composition Change, NDACC) and space-based (Infrared Atmospheric Sounding Interferometer, IASI) FTIR remote sensing measurements of δD(H2O) as a means to validate the remote sensing humidity and δD(H2O) data products. The results of the validation are presented in detail in a separate paper (Schneider et al., 2014). The profiles were obtained with a high vertical resolution of around 3 m. By analyzing humidity and δD(H2O) correlations we were able to identify different layers of air masses with specific isotopic signatures. The results are discussed. © Author(s) 2015

Planetary nebulae with Wolf-Rayet-type central stars -- I. The case of the high-excitation NGC 2371

We present the analysis of the planetary nebula (PN) NGC 2371 around the [Wolf-Rayet] ([WR]) star WD 0722$+$295. Our Isaac Newton Telescope (INT) Intermediate Dispersion Spectrograph (IDS) spectra, in conjunction with archival optical and UV images, unveil in unprecedented detail the high-ionisation of NGC 2371. The nebula has an apparent multipolar morphology, with two pairs of lobes protruding from a barrel-like central cavity, a pair of dense low-ionisation knots misaligned with the symmetry axis embedded within the central cavity, and a high excitation halo mainly detected in He II. The abundances from the barrel-like central cavity and dense knots agree with abundance determinations for other PNe with [WR]-type CSPNe. We suggest that the densest knots inside NGC 2371 are the oldest structures, remnant of a dense equatorial structure, whilst the main nebular shell and outer lobes resulted from a latter ejection that ended the stellar evolution. The analysis of position-velocity diagrams produced from our high-quality spectra suggests that NGC 2371 has a bipolar shape with each lobe presenting a double-structure protruding from a barrel-like central region. The analysis of the spectra of WD 0722$+$295 results in similar stellar parameters as previously reported. We corroborate that the spectral sub-type corresponds with a [WO1] type.Comment: 15 pages, 12 figures, 5 tables; accepted to MNRA

Influence of major mergers on the radio emission of elliptical galaxies

We investigate the influence of major mergers on the radio emission of elliptical galaxies. We use a complete sample of close pairs, which contains 475 merging and 1828 non-merging paired elliptical galaxies of M_r<-21.5 selected from the Sloan Digital Sky Survey. In addition, a control sample of 2000 isolated field galaxies is used for comparison. We cross-identify the optical galaxies with the radio surveys of FIRST and NVSS. We find that the radio fraction of merging paired galaxies is about 6%, which is slightly higher than the 5% obtained for non-merging paired galaxies, although these values are consistent with each other owing to the large uncertainty caused by the limited sample. The radio fraction is twice as that of isolated galaxies, which is less than 3%. Radio emission of elliptical galaxies is only slightly affected by major mergers, but predominantly depends on their optical luminosities. Therefore, merging is not important in triggering the radio emission of elliptical galaxies.Comment: 5 pages, 5 figures, 1 table, accepted for publication in A&A, minor change

Geochemistry of atmospheric aerosols in Andalusia (Southern Spain)

Comunicación presentada en: V Reunión Española de Ciencia y Tecnología de Aerosoles – RECTA 2011 celebrada del 27 al 29 de junio de 2011 en CIEMAT, Madrid

Modelling the strongest silicate emission features of local type 1 AGN

We measure the 10 and $18\mu$m silicate features in a sample of 67 local ($z<0.1$) type 1 active galactic nuclei (AGN) with available {\it Spitzer} spectra dominated by non-stellar processes. We find that the $10\mu$m silicate feature peaks at $10.3^{+0.7}_{-0.9}\mu$m with a strength (Si$_{p}$ = ln f$_{p}$(spectrum)/f$_{p}$(continuum)) of $0.11^{+0.15}_{-0.36}$, while the $18\mu$m one peaks at $17.3^{+0.4}_{-0.7}\mu$m with a strength of $0.14^{+0.06}_{-0.06}$. We select from this sample sources with the strongest 10$\mu$m silicate strength ($\sigma_{Si_{10\mu m}}>0.28$, 10 objects). We carry out a detailed modeling of the IRS/{\it Spitzer} spectra by comparing several models that assume different geometries and dust composition: a smooth torus model, two clumpy torus models, a two-phase medium torus model, and a disk+outflow clumpy model. We find that the silicate features are well modeled by the clumpy model of Nenkova et al. 2008, and among all models those including outflows and complex dust composition are the best (Hoenig et al. 2017). We note that even in AGN-dominated galaxies it is usually necessary to add stellar contributions to reproduce the emission at the shortest wavelengths.Comment: Accepted for publication in Ap

Vasoactive intestinal peptide axis is dysfunctional in patients with Graves’ disease

Vasoactive intestinal peptide (VIP) is a neuropeptide with potent immunoregulatory properties. Reduced serum VIP levels and alterations in VIP receptors/signaling on immune cells have been associated with different inflammatory/autoimmune diseases. However, its role in autoimmune thyroid diseases (AITD) remains unknown. This study examined the interrelationship between VIP system, autoimmune background and thyroid hormones in peripheral immune cells in patients with AITD. Only Graves’ disease (GD) patients showed significantly lower serum VIP levels when compared to healthy subjects and to Hashimoto’s thyroiditis patients. Serum VIP levels were lower at the onset of GD, showing a significant negative correlation with thyroid hormone levels. The expression of VIP receptors, VPAC1 and VPAC2, was significantly upregulated in peripheral blood mononuclear cells (PBMC) from GD patients. There was an impairment of VIP signalling in these patients, probably attributable to a dysfunction of VPAC1 with preservation of VPAC2. The correlation between VPAC1 and thyroid hormone receptor expression in PBMC from healthy subjects was lost in GD patients. In summary, the VIP system is altered in peripheral immune cells of GD patients and this finding is associated with different thyroid hormone receptor patterns, showing a dynamic inter-regulation and a prominent role of VIP in this setting.This work has been supported by Instituto de Salud Carlos III, Spain, cofinanced by FEDER, European Union: RETICS program, Red de Investigación en Inflamación y Enfermedades Reumáticas (RD16/0012/0008, PI17/00027, PI16-02091, PIE13-0004) and from Consejería de Educación, Juventud y Deporte, Comunidad de Madrid: B2017/BMD372

Conceptual design of the ITER fast-ion loss detector

A conceptual design of a reciprocating fast-ion loss detector for ITER has been developed and is presented here. Fast-ion orbit simulations in a 3D magnetic equilibrium and up-to-date first wall have been carried out to revise the measurement requirements for the lost alpha monitor in ITER. In agreement with recent observations, the simulations presented here suggest that a pitch-angle resolution of ∼5 ◦ might be necessary to identify the loss mechanisms. Synthetic measurements including realistic lost alpha-particle as well as neutron and gamma fluxes predict scintillator signal-to-noise levels measurable with standard light acquisition systems with the detector aperture at ∼11 cm outside of the diagnostic first wall. At measurement position, heat load on detector head is comparable to that in present devices.Marie Curie FP7 Integration PCIG11-GA2012-321455Ministerio de Economía y Competitividad RYC-2011-09152, FIS2015-69362-P, ENE2012- 3108

Identification of candidate pelagic marine protected areas through a seabird seasonal-, multispecific- and extinction risk-based approach

With increasing pressure on the oceans from environmental change, there has been a global call for improved protection of marine ecosystems through the implementation of marine protected areas (MPAs). Here, we used species distribution modelling (SDM) of tracking data from 14 seabird species to identify key marine areas in the southwest Atlantic Ocean, valuing areas based on seabird species occurrence, seasonality and extinction risk. We also compared overlaps between the outputs generated by the SDM and layers representing important human threats (fishing intensity, ship density, plastic and oil pollution, ocean acidification), and calculated loss in conservation value using fishing and ship density as cost layers. The key marine areas were located on the southern Patagonian Shelf, overlapping extensively with areas of high fishing activity, and did not change seasonally, while seasonal areas were located off south and southeast Brazil and overlapped with areas of high plastic pollution and ocean acidification. Non-seasonal key areas were located off northeast Brazil on an area of high biodiversity, and with relatively low human impacts. We found support for the use of seasonal areas depending on the seabird assemblage used, because there was a loss in conservation value for the seasonal compared to the non-seasonal approach when using ‘cost’ layers. Our approach, accounting for seasonal changes in seabird assemblages and their risk of extinction, identified additional candidate areas for incorporation in the network of pelagic MPAs