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E-Prints Complutense (107.086 recursos)

En este archivo los docentes e investigadores de la UCM depositan sus documentos en acceso abierto (open access)

Tipo = Artículo

Mostrando recursos 1 - 20 de 1.442

  1. La desecación de las Tablas de Daimiel (1750-1987): cambios agrarios e impactos medioambientales a partir de la interpretación del registro sedimentario

    Celis, Alberto; Mediavilla López, Rosa María; Santisteban, Juan I.; Castaño Castaño, Silvino; Losa, Almudena de la
    El Parque Nacional de lasTablas de Daimiel es un humedal de importancia internacional sometido a una fuerte presión agraria desde el siglo XVIII.El impacto de dicha presión ha sido analizado a partir del estudio de los sedimentos acumulados en el interior del humedal. Se han encontrado varias anomalías sedimentarias que separan al humedal de su comportamiento natural.Se han establecido cuatro épocas de alteración importantes:el primer proyecto de desecación en la dé cada de 1750;el aumento de la superficie cultivada en el entorno durante la segunda mitad del siglo XIX;el intento de desecación promovido durante la Segunda República; y la degradación...

  2. Biocatalyzed synthesis of antidiabetic drugs: A review

    Alcántara, Cristina M.; Alcántara León, Andrés R.
    The biocatalyzed production of building blocks for synthesizing drugs is a very attractive research field, because of the sustainability introduced in a synthetic schedule when chemical steps are substituted by biocatalyzed protocols. In this article, we will show how different antidiabetic drugs, for treating diabetes mellitus Type 1 and Type 2, can be more efficiently and effectively synthetized with the help of different types of biocatalysts. The huge overall drug market for these drugs, as well as the great number of people suffering from diabetes (the prevalence of all types of diabetes is growing), makes this topic attractive enough to...

  3. Differential responses of Miocene rodent metacommunities to global climatic changes were mediated by environmental context

    Blanco, Fernando; Gómez Cano, Ana Rosa; Cantalapiedra, Juan L.; Domingo, Maria Soledad; Domingo, Laura; Menéndez, Iris; Flynn, Lawrence J.; Hernández Fernández, Manuel
    The study of how long-term changes affect metacommunities is a relevant topic, that involves the evaluation of connections among biological assemblages across different spatio-temporal scales, in order to fully understand links between global changes and macroevolutionary patterns. We applied multivariate statistical analyses and diversity tests using a large data matrix of rodent fossil sites in order to analyse long-term faunal changes. Late Miocene rodent faunas from southwestern Europe were classified into metacommunities, presumably sharing ecological affinities, which followed temporal and environmental non-random assembly and disassembly patterns. Metacommunity dynamics of these faunas were driven by environmental changes associated with temperature variability,...

  4. Avian and crocodilian eggshells from the upper Barremian site of Vadillos-1 (Lower Cretaceous, Cuenca province, Spain)

    Bravo, Ana M.; Sevilla, Paloma; Barroso Barcenilla, Fernando
    The new upper Barremian microfossil site of Vadillos-1 (Lower Cretaceous, Beteta Gorges, Cuenca province, Spain) has yielded a rich fossil assemblage consisting of numerous eggshell fragments along with diverse skeletal remains of fishes, amphibians, turtles, crocodyliforms and dinosaurs. Crocodilian eggshells constitute the main fraction of the eggshell assemblage which includes abundant material belonging to the oofamily Krokolithidae, as well as a new type of crocodilian eggshells (Neokrokolithes trigonalis oogen. et oosp. nov.) characterised by a type of ornamentation and microstructure of the basal knobs not described before. Few fragments of the oospecies cf. Mycomorphoolithus kohringi, attributed to non-eusuchian crocodylomorphs, have...

  5. Major merging history in CANDELS. I. Evolution of the incidence of massive galaxy-galaxy pairs from z=3 to z ∼ 0

    Pérez González, Pablo Guillermo; otros, ...
    The rate of major galaxy-galaxy merging is theoretically predicted to steadily increase with redshift during the peak epoch of massive galaxy development (1 <= z <= 3). We use close-pair statistics to objectively study the incidence of massive galaxies (stellar M1 > 2 x 10(10)M(circle dot)) hosting major companions (1 <= M-1/M-2 <= 4; i.e. <4: 1) at six epochs spanning 0 < z < 3. We select companions from a nearly complete, mass-limited (>= 5 x 10(9)M(circle dot)) sample of 23 696 galaxies in the five Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey fields and the Sloan Digital Sky...

  6. Planarity vs. Non-Planarity in the Electronic Communication of TCAQ-Based Push-Pull Chromophores

    García, Raúl; Calbo, Joaquín; Viruela, Rafael; Herranz, Maria Ángeles; Ortí, Enrique; Martín, Nazario
    Donor-acceptor alkynes, endowed with 11,11,12,12-tetracyano-9,10-anthraquinodimethane (TCAQ) and N,N-dimethylaniline (DMA) units, have been further functionalized by a [2+2] tetracyanoethylene (TCNE) cycloaddition followed by a subsequent retroelectrocyclization to form distorted non-planar molecular structures with 1,1,4,4-tetracyanobuta-1,3-diene (TCBD) bridge ligands. Comprehensive spectroscopic, electrochemical, and computational studies have been carried out to compare the electronic communication in these planar (alkyne) and nonplanar (with TCBD units) TCAQ-based push-pull chromophores. Cyclic voltammetry and UV-Vis absorption measurements confirm a noticeable electronic communication between the TCAQ and DMA units regardless the quasi-orthogonal arrangement of the two dicyanovinyl halves of the TCBD groups, which partially hinder the electronic communication. The...

  7. A Fluorescent Probe to Unravel Functional Features of Cannabinoid Receptor CB1 in Human Blood and Tonsil Immune System Cells

    Martín Fontecha, María del Mar; Angelina Querencias, Alba; Rückert, Beate; Rueda Zubiaurre, Ainoa; Martín Cruz, Leticia; Veen, Willem van de; Akdis, Mübeccel; Ortega Gutiérrez, Silvia; López Rodríguez, María Luz; Akdis, Cezmi A.; Palomares, Oscar
    The human endogenous cannabinoid system (ECS) regulates key physiological processes and alterations in its signaling pathways, and endocannabinoid levels are associated with diseases such as neurological and neuropsychiatric conditions, cancer, pain and inflammation, obesity, and metabolic and different immune related disorders. Immune system cells express the G-protein coupled cannabinoid receptor 1 (CB1), but its functional role has not been fully understood, likely due to the lack of appropriate tools. The availability of novel tools to investigate the role of CB1 in immune regulation might contribute to identify CB1 as a potential novel therapeutic target or biomarker for many diseases. Herein,...

  8. Predictability of Tunnel Depth for Intrastromal Corneal Ring Segments Implantation Between Manual and Femtosecond Laser Techniques

    Monteiro, Tiago; Alfonso, José F.; Franqueira, Nuno; Faria Correira, Fernando; Ambrósio, Renato; Madrid Costa, David
    PURPOSE: To compare the predictability of intrastromal tunnel depth creation for intrastromal corneal ring segments (ICRS) implantation between manual dissection and femtosecond laser using a high-resolution anterior segment optical coherence tomography (AS-OCT). METHODS: This multicenter study included patients with keratoconus who had Ferrara-type ICRS implantation at Hospital de Braga using manual dissection and at the Fernandez-Vega Ophthalmological Institute using the femtosecond laser technique. The intended depth of implantation was compared to the achieved postoperative ICRS depth of each case, measured using a swept-source AS-OCT (CASIA SS-1000; Tomey Corporation, Nagoya, Japan) at three points (proximal, central, and distal end of the implant). RESULTS:...

  9. Exoplanets around Low-mass Stars Unveiled by K2

    Montes Gutiérrez, David; otros, ...
    We present the detection and follow-up observations of planetary candidates around low-mass stars observed by the K2 mission. Based on light-curve analysis, adaptive-optics imaging, and optical spectroscopy at low and high resolution (including radial velocity measurements), we validate 16 planets around 12 low-mass stars observed during K2 campaigns 5-10. Among the 16 planets, 12 are newly validated, with orbital periods ranging from 0.96 to 33 days. For one of the planets (K2-151b), we present ground-based transit photometry, allowing us to refine the ephemerides. Combining our K2 M-dwarf planets together with the validated or confirmed planets found previously, we investigate the...

  10. Polymorphic nature of iron and degree of lattice preferred orientation beneath the Earth's inner core boundary

    Mattesini, Maurizio; Belonoshko, Anatoly B.; Tkalcic, Hrvoje
    Deciphering the polymorphic nature and the degree of iron lattice-preferred orientation in the Earth's inner core holds a key to understanding the present status and evolution of the inner core. A multiphase lattice-preferred orientation pattern is obtained for the top 350 km of the inner core by means of the ab initio based Candy Wrapper Velocity Model coupled to a Monte Carlo phase discrimination scheme. The achieved geographic distribution of lattice alignment is characterized by two regions of freezing, namely within South America and the Western Central Pacific, that exhibit an uncommon high degree of lattice orientation. In contrast, widespread...

  11. Star Formation in the Local Universe from the CALIFA Sample. II. Activation and Quenching Mechanisms in Bulges, Bars, and Disks

    Catalán Torrecilla, Cristina; Gil de Paz, Armando; Castillo Morales, África
    We estimate the current extinction-corrected Ha star formation rate (SFR) of the different morphological components that shape galaxies (bulges, bars, and disks). We use a multicomponent photometric decomposition based on Sloan Digital Sky Survey imaging to Calar Alto Legacy Integral Field Area Integral Field Spectroscopy (IFS) datacubes for a sample of 219 galaxies. This analysis reveals an enhancement of the central SFR and specific SFR (sSFR = SFR/M-star) in barred galaxies. Along the main sequence, we find that more massive galaxies in total have undergone efficient suppression (quenching) of their star formation, in agreement with many studies. We discover that...

  12. Parametrizing growth in dark energy and modified gravity models

    Aparicio Resco, Miguel; López Maroto, Antonio
    It is well known that an extremely accurate parametrization of the growth function of matter density perturbations in ACDM cosmology, with errors below 0.25%, is given by f(a) = Ω^(γ)_(m)(a) with γ ≃ 0.55. In this work, we show that a simple modification of this expression also provides a good description of growth in modified gravity theories. We consider the model-independent approach to modified gravity in terms of an effective Newton constant written as μ(a, k) = G_(eff)/G and show that f(a) = β(a) Ω^(γ)_(m)(a) provides fits to the numerical solutions with similar accuracy to that of ACDM. In the...

  13. Dynamic variational study of chaos: spin glasses in three dimensions

    Billoire, A.; Fernández Pérez, Luis Antonio; Maiorano, A.; Martín Mayor, Víctor; Moreno Gordo, J.; Parisi, G.; Ricci-Tersenghi, F.; Ruiz Lorenzo, J. J.
    We have introduced a variational method to improve the computation of integrated correlation times in the Parallel Tempering Dynamics, obtaining a better estimate (a lower bound, at least) of the exponential correlation time. Using this determination of the correlation times, we revisited the problem of the characterization of the chaos in temperature in finite dimensional spin glasses spin by means of the study of correlations between different chaos indicators computed in the static and the correlation times of the Parallel Tempering dynamics. The sample-distribution of the characteristic time for the Parallel Tempering dynamics turns out to be fat-tailed and it...

  14. SHARDS: constraints on the dust attenuation law of star-forming galaxies at z∼2

    Pérez González, Pablo Guillermo; Alcalde Pampliega, Belén; Domínguez Sánchez, Helena; Eliche Moral, María del Carmen; Espino Briones, Néstor; Hernán Caballero, Antonio
    We make use of the Survey of High-z Absorption Red and Dead Sources, an ultradeep (<26.5AB) galaxy survey that provides optical photospectra at resolution R similar to 50, via medium-band filters (FWHM similar to 150 angstrom). This data set is combined with ancillary optical and NIR fluxes to constrain the dust attenuation law in the rest-frame NUV region of star-forming galaxies within the redshift window 1.5 < z < 3. We focus on the NUV bump strength (B) and the total-to-selective extinction ratio (R-V), targeting a sample of 1753 galaxies. By comparing the data with a set of population synthesis...

  15. Removal of the blue component of light significantly decreases retinal damage after high intensity exposure

    Vicente-Tejedor, Javier; Marchena, Miguel; Ramírez, Laura; García Ayuso, Diego; Gómez Vicente, Violeta; Sánchez Ramos, Celia; Villa Polo, Pedro de la; Germain, Francisco
    Light causes damage to the retina (phototoxicity) and decreases photoreceptor responses to light. The most harmful component of visible light is the blue wavelength (400–500 nm). Different filters have been tested, but so far all of them allow passing a lot of this wavelength (70%). The aim of this work has been to prove that a filter that removes 94% of the blue component may protect the function and morphology of the retina significantly. Three experimental groups were designed. The first group was unexposed to light, the second one was exposed and the third one was exposed and protected by...

  16. Measures of critical exponents in the four-dimensional site percolation

    Ballesteros, H.G.; Fernández Pérez, Luis Antonio; Martín Mayor, Víctor; Muñoz Sudupe, Antonio; Parisi, G.; Ruiz Lorenzo, J. J.
    Using finite-size scaling methods we measure the thermal and magnetic exponents of the site percolation in four dimensions, obtaining a value for the anomalous dimension very different from the results found in the literature. We also obtain the leading corrections-to-scaling exponent and, with great accuracy, the critical density.

  17. A lattice field theoretical model for high-T_(c) superconductivity

    Alonso, J.L.; Boucaud, Ph.; Martín Mayor, Víctor; van der Sijs, A.J.
    We present a 2+1-dimensional lattice model for the copper oxide superconductors and their parent compounds, in which both the charge and spin degrees of freedom are treated dynamically. The spin-charge coupling parameter is associated to the doping fraction in the cuprates. The model is able to account for the various phases of the cuprates and their properties, not only at low and intermediate doping but also for (highly) over-doped compounds. We acquire a qualitative understanding of highTc superconductivity as a Bose-Einstein condensation of boun d charge pairs.

  18. Finite-size scaling study of the d=4 site-diluted Ising model

    Ballesteros, H.G.; Fernández Pérez, Luis Antonio; Martín Mayor, Víctor; Muñoz Sudupe, Antonio; Parisi, G.; Ruiz-Lorenzo, J. J.
    We study the four dimensional site-diluted Ising model using finite-size scaling techniques. We explore the whole parameter space (density-coupling) in order to determine the Universality Class of the transition line. Our data are compatible with Mean Field behavior plus logarithmic corrections.

  19. The nature of giant clumps in distant galaxies probed by the anatomy of the cosmic snake

    Cava, Antonio; Schaerer, Daniel; Richard, Johan; Pérez González, Pablo Guillermo; Dessauges-Zavadsky, Miroslava; Mayer, Lucio; Tamburello, Valentina
    Giant stellar clumps are ubiquitous in high-redshift galaxies(1,2). They are thought to play an important role in the build-up of galactic bulges(3) and as diagnostics of star formation feedback in galactic discs(4). Hubble Space Telescope (HST) blank field imaging surveys have estimated that these clumps have masses of up to 10(9.5) M-circle dot and linear sizes of greater than or similar to 1 kpc(5,6). Recently, gravitational lensing has also been used to get higher spatial resolution(7-9). However, both recent lensed observations(10,11) and models(12,13) suggest that the clumps' properties may be overestimated by the limited resolution of standard imaging techniques. A...

  20. The relationship between galaxy and dark matter halo size from z ∼ 3 to the present

    Pérez González, Pablo Guillermo; otros, ...
    We explore empirical constraints on the statistical relationship between the radial size of galaxies and the radius of their host dark matter haloes from z similar to 0.1-3 using the Galaxy And Mass Assembly (GAMA) and Cosmic Assembly Near Infrared Deep Extragalactic Legacy Survey (CANDELS) surveys. We map dark matter halo mass to galaxy stellar mass using relationships from abundance matching, applied to the Bolshoi-Planck dissipationless N-body simulation. We define SRHR equivalent to r(e)/R-h as the ratio of galaxy radius to halo virial radius, and SRHR lambda equivalent to r(e)/(lambda R-h) as the ratio of galaxy radius to halo spin...

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