447 research outputs found
The end of the Last Glacial Maximum in the Iberian Peninsula characterized by the small-mammal assemblages
This paper presents a palaeoenvironmental and palaeoclimatic approach to the end of the Last Glacial Maximum (LGM) in the Iberian Peninsula on the basis of the small-mammal assemblages (insectivores, bats and rodents). The LGM is an important period in our climate history defined by the maximum extension of ice sheets between ca. 22 and 19 ka BP. In the Mediterranean region the LGM is characterized by humid conditions, which allow for the development of arboreal vegetation. The small-mammal remains described in this study were recovered from four different sites within the Iberian Peninsula: El Mirón cave (Ramales de la Victoria, Cantabria), Valdavara-1 (Becerreá, Lugo), El Portalón (Sierra de Atapuerca, Burgos), and Sala de las Chimeneas (Maltravieso, Cáceres). We found in these sites a non-analogue association represented by species associated with mid-European climatic conditions, such as the voles Chionomys nivalis, Microtus arvalis, Microtus agrestis and Microtus oeconomus, together with species associated with Mediterranean requirements, such as Microtus (Iberomys) cabrerae and Microtus (Terricola) duodecimcostatus. These assemblages reveal that the climate was harsher than today in the sites under study, though not as rigorous as elsewhere in Europe, with mean annual temperatures lower than present and an environment dominated by wet open meadows. All our data have been compared with other environmental and climatic proxies, global isotope curves and pollen data, providing a scenario for the palaeoclimatic and palaeoenvironmental conditions that occurred during the LGM in the Iberian Peninsula.Este artículo representa un enfoque paleoambiental y paleoclimático del final del Último Máximo Glacial (UMG), en la Península Ibérica a partir de las asociaciones de pequeños mamíferos (insectívoros, murciélagos y roedores). El UMG es un período importante en nuestra historia del clima definido por la máxima extensión de las capas de hielo entre ca. 22 y 19 ka BP. En la región del Mediterráneo, este UMG se caracteriza por condiciones de humedad, que permiten el desarrollo de la vegetación arbórea. Los restos de micromamíferos seleccionados para este estudio corresponden a cuatro yacimientos diferentes de la Península Ibérica: la cueva del Mirón (Ramales de la Victoria, Cantabria), Valdavara-1 (Becerreá, Lugo), El Portalón (Sierra de Atapuerca, Burgos), y la Sala de las Chimeneas (Maltravieso, Cáceres). En todos los yacimientos estudiados se ha encontrado una asociación representada por las especies relacionadas con las condiciones climáticas medio-europeas, como los topillos Chionomys nivalis, Microtus arvalis, Microtus agrestis o Microtus oeconomus, junto con las especies asociadas con los requerimientos mediterráneos, como Microtus (Iberomys) cabrerae o Microtus (terricola) duodecimcostatus. Estas asociaciones nos permiten observar que el clima era más frío que hoy en día en los diferentes yacimientos estudiados, pero no tan riguroso como en otros lugares de Europa, con temperaturas medias anuales más bajas que en la actualidad y un entorno dominado por prados húmedos. Los resultados de este estudio han sido comparados con otros datos ambientales y climáticos, las curvas climáticas globales de isótopos y datos polínicos, proporcionando un escenario para las condiciones paleoclimáticas y paleoambientales que ocurrieron durante el UMG en la Península Ibérica
Small mammals from the middle pleistocene layers of the sima del elefante (Sierra de Atapuerca, Burgos, northwestern Spain)
The Sima del Elefante site, located in the Sierra de Atapuerca (Burgos, Spain), is an important Pleistocene archaeopalaeontological locality that has been excavated every year since 1996. At least two main infill phases have been identified: a first (TELRU) early Pleistocene phase that has provided a rich faunal assemblage, various stone tools and the earliest human remains from western Europe; and a second phase (TEURU) attributed to the Middle Pleistocene. In this paper, for the first time we present a description of the TEURU small-mammal assemblage and its subsequent biochronological, palaeoenvironmental and palaeoclimatic implications. The small-mammal assemblage is highly diverse and comprises at least 17 species: 3 insectivores (cf. Erinaceus sp., Crocidura sp. and Sorex sp.); 4 chiropters (Rhinolophus ferrumequinum, Rhinolophus gr. euryale-mehelyi, Myotis gr. Myotisoxygnathus and Miniopteurs schreibersii); 9 rodents (Myodes glareolus, Microtus arvalis, Microtus agrestis, Iberomys brecciensis, Terricola cf. atapuerquensis, Arvicola sp., Apodemus sylvaticus, Eliomys quercinus and Allocricetus bursae) and 1 lagomorph (Oryctolagus sp.). Such an association suggests a late Middle Pleistocene age (ca. 250-350 ka), a patchy landscape dominated by humid meadows and woodland areas, and mild climatic conditions. These results are compared with other proxies, such as the herpetofauna, malacofauna, large-mammals and charcoals, providing a new scenario for the climatic and environmental conditions that prevailed during the latest Middle Pleistocene in the Sierra de Atapuerca
SK channels contribution to ventricular electrophysiology in heart failure patients
Heart failure (HF) is characterized by deterioration of the electrical and contractile function of the heart due to structural and functional remodelling, leading to development of arrhythmias and increased sudden cardiac death risk. SK channels are a type of calcium-activated potassium channels that do not play a relevant role in normal ventricular electrophysiology. However, it has been hypothesized that these channels become more relevant in pathologies such as HF. Nontheless, their role in human ventricular electrophysiology is not fully characterized
Microglial Hemoxygenase-1 Deletion Reduces Inflammation in the Retina of Old Mice with Tauopathy
Tauopathies such as Alzheimer’s disease are characterized by the accumulation of neurotoxic aggregates of tau protein. With aging and, especially, in Alzheimer’s patients, the inducible enzyme heme oxygenase 1 (HO-1) progressively increases in microglia, causing iron accumulation, neuroinflammation, and neurodegeneration. The retina is an organ that can be readily accessed and can reflect changes that occur in the brain. In this context, we evaluated how the lack of microglial HO-1, using mice that do not express HO-1 in microglia (HMO-KO), impacts retinal macro and microgliosis of aged subjects (18 months old mice) subjected to tauopathy by intrahippocampal delivery of AAV-hTauP301L (TAU). Our results show that although tauopathy, measured as anti-TAUY9 and anti-AT8 positive immunostaining, was not observed in the retina of WT-TAU or HMO-KO+TAU mice, a morphometric study of retinal microglia and macroglia showed significant retinal changes in the TAU group compared to the WT group, such as: (i) increased number of activated microglia, (ii) retraction of microglial processes, (iii) increased number of CD68+ microglia, and (iv) increased retinal area occupied by GFAP (AROA) and C3 (AROC3). This retinal inflammatory profile was reduced in HMO-KO+TAU mice. Conclusion: Reduction of microglial HO-1 could be beneficial to prevent tauopathy-induced neuroinflammation.Depto. de Inmunología, Oftalmología y ORLUnidad Docente de Inmunología, Oftalmología y ORLFac. de MedicinaFac. de Óptica y OptometríaTRUEMinisterio de Ciencia e Innovación de EspañaMinisterio de Ciencia, Innovación y Universidades de EspañaUniversidad Complutense de Madridpu
The Role of Autophagy in Eye Diseases
This research was funded by the Ophthalmological Network OFTARED (Enfermedades oculares: Prevención, detección precoz, tratamiento y rehabilitación de las patologías oculares) (RD16/0008/0005 and RD16/0008/0026) of the Institute of Health of Carlos III of the Spanish Ministry of Economy and by the European programme FEDER; and Network RETiBRAIN (La retina un modelo para investigar Neuroprotección en patologías del Sistema Nervioso Central) (RED2018-102499-T) of Spanish Ministry of Science and Innovation. And J.A.F.-A. is currently funded by a Predoctoral Fellowship (FPU17/01023) from the Spanish Ministry of Science, Innovation, and Universities; and I.L.-C. is currently funded by a Predoctoral Fellowship (CT42/18-CT43/18) from the Complutense University of Madrid.Autophagy is a catabolic process that ensures homeostasis in the cells of our organism. It plays a crucial role in protecting eye cells against oxidative damage and external stress factors. Ocular pathologies of high incidence, such as age-related macular degeneration, cataracts, glaucoma, and diabetic retinopathy are of multifactorial origin and are associated with genetic, environmental factors, age, and oxidative stress, among others; the latter factor is one of the most influential in ocular diseases, directly affecting the processes of autophagy activity. Alteration of the normal functioning of autophagy processes can interrupt organelle turnover, leading to the accumulation of cellular debris and causing physiological dysfunction of the eye. The aim of this study is to review research on the role of autophagy processes in the main ocular pathologies, which have a high incidence and result in high costs for the health system. Considering the role of autophagy processes in cell homeostasis and cell viability, the control and modulation of autophagy processes in ocular pathologies could constitute a new therapeutic approach.Depto. de Inmunología, Oftalmología y ORLFac. de MedicinaTRUEUnión EuropeaMinisterio de Ciencia e Innovación (España)Instituto de Salud Carlos IIIUniversidad Complutense de Madridpu
Anatomy of the Human Optic Nerve: Structure and Function
The optic nerve (ON) is constituted by the axons of the retinal ganglion cells (RGCs). These axons are distributed in an organized pattern from the soma of the RGC to the lateral geniculated nucleus (where most of the neurons synapse). The key points of the ON are the optic nerve head and chiasm. This chapter will include a detailed and updated review of the ON different parts: RGC axons, glial cells, connective tissue of the lamina cribrosa and the septum and the blood vessels derivate from the central retina artery and from the ciliary system. There will be an up-to-date description about the superficial nerve fibre layer, including their organization, and about prelaminar, laminar and retrolaminar regions, emphasizing the axoplasmic flow, glial barriers, biomechanics of the lamina cribrosa and the role of the macro- and microglia in their working
Structural, Vibrational, and Electronic Study of Sb2S3 at High Pressure
Antimony trisulfide (Sb2S3), found in nature as the mineral stibnite, has been studied under compression at room temperature from a joint experimental and theoretical perspective. X-ray diffraction and Raman scattering measurements are complemented with ab initio total-energy, lattice-dynamics, and electronic structure calculations. The continuous changes observed in the volume, lattice parameters, axial ratios, bond lengths, and Raman mode frequencies as a function of pressure can be attributed to the different compressibility along the three orthorhombic axes in different pressure ranges, which in turn are related to the different compressibility of several interatomic bond distances in different pressure ranges. The structural and vibrational properties of Sb2S3 under compression are compared and discussed in relation to isostructural Bi2S3 and Sb2Se3. No first-order phase transition has been observed in Sb2S3 up to 25 GPa, in agreement with the stability of the Pnma structure in Bi2S3 and Sb2Se3 previously reported up to 50 GPa. Our measurements and calculations do not show evidence either for a pressure-induced second-order isostructural phase transition or for an electronic topological transition in Sb2S3.This work has been performed under financial support from Spanish MINECO under Projects MAT2013-46649-C4-2/3-P and MAT2015-71070-REDC. This publication is fruit of "Programa de Valoracion y Recursos Conjuntos de I+D+i VLC/CAMPUS" and has been financed by the Spanish Ministerio de Educacion, Cultura y Deporte, as part of "Programa Campus de Excelencia Internacional" through Projects SP20140701 and SP20140871. These experiments were performed at BL04-MSPD beamline at ALBA Synchrotron with the collaboration of ALBA staff. Supercomputer time has been provided by the Red Espanola de Supercomputacion (RES) and the MALTA cluster. J.A.S. acknowledges financial support through Juan de la Cierva fellowship.Ibáñez, J.; Sans-Tresserras, JÁ.; Popescu, C.; López-Vidrier, J.; Elvira-Betanzos, J.; Cuenca Gotor, VP.; Gomis, O.... (2016). Structural, Vibrational, and Electronic Study of Sb2S3 at High Pressure. Journal of Physical Chemistry C. 19(120):10547-10558. https://doi.org/10.1021/acs.jpcc.6b01276S10547105581912
DERIVE and Linear Algebra
This work describes an experience with a methodology for learning based on competences in Linear Algebra for engineering students. The experience has been based in autonomous team work of students. DERIVE tutorials for Linear Algebra topics are provided to the students. They have to work with the tutorials as their homework. After, worksheets with exercises have been prepared to be solved by the students organized in teams, using DERIVE function previously defined in the tutorials. The students send to the instructor the solution of the proposed exercises and they fill a survey with their impressions about the following items: ease of use of the files, usefulness of the tutorials for understanding the mathematical topics and the time spent in the experience. As a final work, we have designed an activity directed to the interested students. They have to prepare a project, related with a real problem in Science and Engineering. The students are free to choose the topic and to develop it but they have to use DERIVE in the solution. Obviously they are guided by the instructor. Some examples of activities related with Orthogonal Transformations will be presented
Psychometric properties of the Clarke questionnaire for hypoglycemia awareness in the Spanish population with type 2 diabetes
Objectives: The Clarke questionnaire, validated in Spanish language, assesses hypoglycemia awareness
in patients with type 1 diabetes. This study aimed to analyze its psychometric properties in patients
with type 2 diabetes (T2DM).
Methods: This was a questionnaire validation study. Patients with T2DM and treated with insulin,
sulfonylureas or glinides were consecutively recruited from six endocrinology consultations and six
primary care centers. The internal structure of the 8-item Clarke questionnaire was analyzed by
exploratory (training sample) and confirmatory (testing sample) factor analysis; the internal consistency
using Omega’s McDonald coefficient; and goodness of fit with comparative fit index (CFI, cutoff >0.9),
Goodness of Fit Index (GFI, cutoff >0.9), and root mean-square error of approximation (RMSEA, cutoff
<0.09), as well as unidimensionality indicators.
Results: The 265 participants (56.8% men) had a mean age of 67.8 years. Confirmatory factor analysis
for one dimension obtained poor indicators: fit test (p < 0.001); CFI = 0.748; RMSEA = 0.122 and
SRMR = 0.134. Exploratory factor analysis showed 2 or 3 dimensions with poor adjustment indicators.
Omega’s McDonald was 0.739.
Conclusions: The Spanish version of the Clarke questionnaire was not valid or reliable for assessing
hypoglycemia awareness in people with T2DM in Spanish population
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