Organic matter sources for tidal marsh sediment over the past two millennia in the Minho River estuary (NW Iberian Peninsula)

Environmental changes during the last 2 millennia in the Minho River tidal marsh (NW Portugal-Spain border) were reconstructed. Changes in the sources of organic matter (OM) delivered to the marsh were evaluated from elemental, isotopic and molecular composition using a 1 m sediment core. Carbon isotopic composition (delta13C) and organic carbon to total nitrogen ratio (Corg/N) provided valuable information concerning the origin of the OM. These parameters indicated a major input from land plants, reaching a maximum at 1100–1200 and 1750–1850 AD. These periods match with major flood events in the NW of the Iberian Peninsula, as reported by several authors. A significant reduction in the terrestrial signature occurred at 6–4 cm (ca. 1960–1985 AD), which is contemporaneous with the construction of several major dams on the Minho River. The distribution of selected lipid biomarkers, including n-alkanes, n-fatty acids and n-alkan-2-ones and specific parameters derived from the molecular distributions, were useful for refining bulk geochemical results. Long chain n- alkanes with an odd number of carbons are indicators of soil-and vascular plant derived terrestrial OM and were dominant throughout the core. In addition, a greater contribution of plankton-derived lipids was observed in the sections corresponding to ca. 1960–1985 AD (6–4 cm) and ca. 100–200 AD (96–94 cm). Although different degradation rates for individual compounds might have partly affected biomarker assemblages, the variations could be attributed to a sharp decrease in the freshwater contribution to the Minho River Estuary (dam construction) and a possible marine highstand, respectively. In addition, several parameters suggested changes in land use (including deforestation and farming) and probably the effects of mining exploitation during the Roman occupation of the area.We acknowledge the funding by the Foundation for Science and Technology (FCT) of Portugal for J.M. M’s PhD. Grant (SFRH/BD/45528/2008) and for the WestLog Project (PTDC/CTE-GIX/105370/2008). E.L. was awarded a Ralph E. Powe Junior Faculty Enhancement Award. This is a contribution to the IGCP Project 588 and to the Geo-Q Research Unit (Aranzadi).Peer reviewe

Marked eburnation among prehispanic individuals from La Gomera (Canary Islands)

Marked eburnation among prehispanic individuals from La Gomera (Canary Islands) Eburnation of the articular surfaces is an advanced feature of osteoarthritis. We here report some striking cases of such a condition in the proximal epiphysis of tibiae of prehispanic inhabitants of La Gomera, in the Canary Archipelago

Semi-Huber quadratic function and comparative study of some MRFs for Bayesian image restoration

The present work introduces an alternative method to deal with digital image restoration into a Bayesian framework, particularly, the use of a new half-quadratic function is proposed which performance is satisfactory compared with respect to some other functions in existing literature. The bayesian methodology is based on the prior knowledge of some information that allows an efficient modelling of the image acquisition process. The edge preservation of objects into the image while smoothing noise is necessary in an adequate model. Thus, we use a convexity criteria given by a semi-Huber function to obtain adequate weighting of the cost functions (half-quadratic) to be minimized. The principal objective when using Bayesian methods based on the Markov Random Fields (MRF) in the context of image processing is to eliminate those effects caused by the excessive smoothness on the reconstruction process of image which are rich in contours or edges. A comparison between the new introduced scheme and other three existing schemes, for the cases of noise filtering and image deblurring, is presented. This collection of implemented methods is inspired of course on the use of MRFs such as the semi-Huber, the generalized Gaussian, the Welch, and Tukey potential functions with granularity control. The obtained results showed a satisfactory performance and the effectiveness of the proposed estimator with respect to other three estimators

Facile synthesis of low band gap ZnO Microstructures

Abstract In this work a simple chemical route was employed to synthesize ZnO microparticles by precipitation from aqueous solution of ZnCl2 as precursor, NaOH as oxidizing and sodium dodecyl sulfate (SDS) as surfactant. Samples of ZnO microparticles were analyzed by scanning electron microscopy (SEM), FTIR spectroscopy, Raman spectroscopy, X-Ray diffraction, UV/Vis-NIR diffusereflectance,highresolutiontransmissionelectronmicroscopy(HR-TEM),andN2 adsorption-desorption.Itwasobserved from SEM analysis that ZnO microparticles with morphologies resembling six-blade impeller with diameters in the range of 500 nm to 1 m, and sheet-like (approximately 200 nm×300 nm) were obtained through this technique. X-Ray diffraction and Raman analyses confirmed the obtaining of hexagonal wurtzite ZnO crystal structure. The calculated band gap energy was 3.19 eV, which is slightly lower than the average value reported in the literature. Specific BET area of ZnO microparticles was 26.5 m2/g. Keywords: ZnO, microstructures, band gap energy, SEM, morphology. Resumen En este trabajo se empleó un a ruta química sencilla para sintetizar micropartículas de ZnO mediante precipitación en solución acuosa de ZnCl2 como precursor, NaOH como oxidante y dodecil sulfato de sodio (SDS) como tensoactivo. Las muestras de ZnO fueron analizadas mediante microscopía de barrido electrónico (SEM), espectroscopía de FTIR, espectroscopía Raman, difracción de rayos-X, reflectancia difusa de UV/Vis-NIR, microscopía de transmisión de electrones de alta resolución (HRTEM), y mediante adsorción-desorción de N2. Se observó mediante análisis de SEM que mediante esta técnica se obtienen micropartículas de ZnO con morfologías similares a impulsores de seis-aspas con diámetros entre 500 nm y 1 m, morfologías tipo-hojas(deaproximadamente200nm×300nm).Losanálisisdedifracciónderayos-XydeRamanconfirmaronlaobtención de ZnO con estructura cristalina wurtzita hexagonal. La energía de band gap calculada fue de 3.19 eV, la cual es ligeramente menor que el valor promedio reportado en la literatura. El área superficial BET de las nanopartículas de ZnO fue de 26.5 m2/g Palabras clave: ZnO, microestructuras, energía de band gap, SEM, morfología

The QUIJOTE experiment: project overview and first results

QUIJOTE (Q-U-I JOint TEnerife) is a new polarimeter aimed to characterize the polarization of the Cosmic Microwave Background and other Galactic and extragalactic signals at medium and large angular scales in the frequency range 10-40 GHz. The multi-frequency (10-20~GHz) instrument, mounted on the first QUIJOTE telescope, saw first light on November 2012 from the Teide Observatory (2400~m a.s.l). During 2014 the second telescope has been installed at this observatory. A second instrument at 30~GHz will be ready for commissioning at this telescope during summer 2015, and a third additional instrument at 40~GHz is now being developed. These instruments will have nominal sensitivities to detect the B-mode polarization due to the primordial gravitational-wave component if the tensor-to-scalar ratio is larger than r=0.05.Comment: To appear in "Highlights of Spanish Astrophysics VIII", Proceedings of the XI Scientific Meeting of the Spanish Astronomical Society, Teruel, Spain (2014

Cognitive clusters in first-episode psychosis

Impairments in a broad range of cognitive domains have been consistently reported in some individuals with first-episode psychosis (FEP). Cognitive deficits can be observed during the prodromal stage. However, the course of cognitive deficits is still unclear. The aim of this study was to identify cognitive subgroups over time and to compare their sociodemographic, clinical and functional profiles. A total of 114 patients with Schizophrenia Spectrum Disorders were included in the present study. We assessed subjects through psychiatric scales and eight neuropsychological tests at baseline and at two-year follow-up visit. We performed the Partition Around Medoids algorithm with all cognitive variables. Furthermore, we performed a logistic regression to identify the predictors related to the different cognitive clusters at follow-up. Two distinct subgroups were found: the first cluster characterized by cognitive impairment and a second cluster had relatively intact cognition in comparison with norms. Up to 54.7% of patients with cognitive deficits at baseline tended to improve during the first two years of treatment. Patients with intact cognition at follow-up had a higher socioeconomic status, later age of onset, lower negative symptoms and a higher cognitive reserve (CR) at baseline. CR and age of onset were the baseline variables that predicted cognitive impairment. This research allows us to obtain a better understanding of the heterogeneous profile of psychotic disorders. Identifying the characteristics of patients who will present a cognitive impairment could improve early detection and intervention. These results suggest that enhancing CR could contribute to improving the course of the illness. © 2021 Elsevier B.V

QUIJOTE-CMB experiment: a technical overview

The QUIJOTE-CMB experiment (Q-U-I JOint TEnerife CMB experiment) is an ambitious project to obtain polarization measurements of the sky microwave emission in the 10 to 47 GHz range. With this aim, a pair of 2,5m telescopes and three instruments are being sited at the Teide Observatory, in Tenerife (Canary Islands, Spain). The first telescope and the first instrument (the MFI: Multi Frequency Instrument) are both already operating in the band from 10 to 20 GHz, since November 2012. The second telescope and the second instrument (TGI: Thirty GHz instrument) is planned to be in commissioning by the end of summer 2014, covering the range of 26 to 36 GHz. After that, a third instrument named FGI (Forty GHz instrument) will be designed and manufactured to complete the sky survey in the frequency range from 37 to 47 GHz. In this paper we present an overview of the whole project current status, from the technical point of view

The QUIJOTE TGI

The QUIJOTE TGI instrument is currently being assembled and tested at the IAC in Spain. The TGI is a 31 pixel 26-36 GHz polarimeter array designed to be mounted at the focus of the second QUIJOTE telescope. This follows a first telescope and multi-frequency instrument that have now been observing almost 2 years. The polarimeter design is based on the QUIET polarimeter scheme but with the addition of an extra 90º phase switch which allows for quasiinstantaneous complete QUI measurements through each detector. The advantage of this is a reduction in the systematics associated with differencing two independent radiometer channels. The polarimeters are split into a cold front end and a warm back end. The back end is a highly integrated design by engineers at DICOM. It is also sufficiently modular for testing purposes. In this presentation the high quality wide band components used in the optical design (also designed in DICOM) are presented as well as the novel cryogenic modular design. Each polarimeter chain is accessible individually and can be removed from the cryostat and replaced without having to move the remaining pixels. The optical components work over the complete Ka band showing excellent performance. Results from the sub unit measurements are presented and also a description of the novel calibration technique that allows for bandpass measurement and polar alignment. Terrestrial Calibration for this instrument is very important and will be carried out at three points in the commissioning phase: in the laboratory, at the telescope site and finally a reduce set of calibrations will be carried out on the telescope before measurements of extraterrestrial sources begin. The telescope pointing model is known to be more precise than the expected calibration precision so no further significant error will be added through the telescope optics. The integrated back-end components are presented showing the overall arrangement for mounting on the cryostat. Many of the microwave circuits are in-house designs with performances that go beyond commercially available products. Individual component performance is be presented showing for each of the sub modules