3,237 research outputs found
Uso de redes sociales como elemento de interacción y construcción de contenidos en el aula: cultura participativa a través de Facebook.
Today, it is necessary to innovate in the classroom with resources used by digital natives. This innovation must be present as a motivator in classrooms; therefore, to implement it is currently a challenge. The social networks have allowed to the teachers interact with students in a more natural way, using the same language that they use for their activities outside the classroom. In this research, we expect to know if students accept the strategy of Facebook implementation in the classroom, as a tool for teaching-learning process in the university.De cara al S.XXI, es necesario innovar dentro de las aulas con recursos utilizados por los nativos digitales. La innovación debe presentarse como elemento motivador, por lo que implementarla es un gran reto. Las redes sociales han permitido que estudiantes y docentes interactúen de una manera más natural al usar lenguajes que utilizan para actividades fuera del aula. En esta Investigación se pretende conocer si la estrategia de implementación de Facebook en las clases, es aceptada por los estudiantes como una herramienta más para el proceso de enseñanza-aprendizaje en el ámbito universitario
Uso de redes sociales como elemento de interacción y construcción de contenidos en el aula: cultura participativa a través de Facebook.
De cara al S.XXI, es necesario innovar dentro de las aulas con recursos utilizados por los nativos digitales. La innovación debe presentarse como elemento motivador, por lo que implementarla es un gran reto. Las redes sociales han permitido que estudiantes y docentes interactúen de una manera más natural al usar lenguajes que utilizan para actividades fuera del aula. En esta Investigación se pretende conocer si la estrategia de implementación de Facebook en las clases, es aceptada por los estudiantes como una herramienta más para el proceso de enseñanza-aprendizaje en el ámbito universitario
Autofluorescence of stingray skeletal cartilage: hyperspectral imaging as a tool for histological characterization
Tessellated cartilage is a distinctive composite tissue forming the bulk of the skeleton of cartilaginous fishes (e.g. sharks and rays), built from unmineralized cartilage covered at the surface by a thin layer of mineralized tiles called tesserae. The finescale structure and composition of elasmobranch tessellated cartilage has largely been investigated with electron microscopy, micro-computed tomography and histology, but many aspects of tissue structure and composition remain uncharacterized. In our study, we demonstrate that the tessellated cartilage of a stingray exhibits a strong and diverse autofluorescence, a native property of the tissue which can be harnessed as an effective label-free imaging technique. The autofluorescence signal was excited using a broad range of wavelengths in confocal and light sheet microscopy, comparing several sample preparations (fresh; demineralized and paraffin-embedded; non-demineralized and plastic-embedded) and imaging the tissue at different scales. Autofluorescence varied with sample preparation with the signal in both plastic- and paraffin-embedded samples strong enough to allow visualization of finescale (≥ 1 μm) cellular and matrix structures, such as cell nuclei and current and former mineralization fronts, identifiable by globular mineralized tissue. A defined pericellular matrix (PCM) surrounding chondrocytes was also discernible, described here for the first time in elasmobranchs. The presence of a PCM suggests similarities with mammalian cartilage regarding how chondrocytes interact with their environment, the PCM in mammals acting as a transducer for biomechanical and biochemical signals. A posterior analysis of hyperspectral images by an MCR-ALS unmixing algorithm allowed identification of several distinct fluorescence signatures associated to specific regions in the tissue. Some fluorescence signatures identified could be correlated with collagen type II, the most abundant structural molecule of cartilage. Other fluorescence signatures, however, remained unidentified, spotlighting tissue regions that deserve deeper characterization and suggesting the presence of molecules still unidentified in elasmobranch skeletal cartilage. Our results show that autofluorescence can be a powerful exploratory imaging tool for characterizing less-studied skeletal tissues, such as tessellated cartilage. The images obtained are largely comparable with more commonly used techniques, but without the need for complicated sample preparations or external staining reagents standard in histology and electron microscopy (TEM, SEM)
The two pion decay of the Roper resonance
We evaluate the two pion decay of the Roper resonance in a model where
explicit re-scattering of the two final pions is accounted for by the use of
unitarized chiral perturbation theory. Our model does not include an explicit
or scalar-isoscalar meson decay mode, instead it
generates it dynamically by means of the pion re-scattering. The two ways,
explicit or dynamically generated, of introducing this decay channel have very
different amplitudes.
Nevertheless, through interference with the other terms of the model we are
able to reproduce the same phenomenology as models with explicit consideration
of the meson.Comment: 17 latex pages, 11 eps figures. A few misprints corrected. A few new
references. Version accepted for publication in Phys. Rev.
Euclid preparation : XVI. Exploring the ultra-low surface brightness Universe with Euclid/VIS
Context. While Euclid is an ESA mission specifically designed to investigate the nature of dark energy and dark matter, the planned unprecedented combination of survey area (similar to 15000 deg(2)), spatial resolution, low sky-background, and depth also make Euclid an excellent space observatory for the study of the low surface brightness Universe. Scientific exploitation of the extended low surface brightness structures requires dedicated calibration procedures that are yet to be tested. Aims. We investigate the capabilities of Euclid to detect extended low surface brightness structure by identifying and quantifying sky-background sources and stray-light contamination. We test the feasibility of generating sky flat-fields to reduce large-scale residual gradients in order to reveal the extended emission of galaxies observed in the Euclid survey. Methods. We simulated a realistic set of Euclid/VIS observations, taking into account both instrumental and astronomical sources of contamination, including cosmic rays, stray-light, zodiacal light, interstellar medium, and the cosmic infrared background, while simulating the effects of background sources in the field of view. Results. We demonstrate that a combination of calibration lamps, sky flats, and self-calibration would enable recovery of emission at a limiting surface brightness magnitude of mu(lim) = 29.5(-0.27)(+0.08) mag arcsec(-2) (3 sigma, 10 x 10 arcsec(2)) in theWide Survey, and it would reach regions deeper by 2 mag in the Deep Surveys. Conclusions. Euclid/VIS has the potential to be an excellent low surface brightness observatory. Covering the gap between pixel-to-pixel calibration lamp flats and self-calibration observations for large scales, the application of sky flat-fielding will enhance the sensitivity of the VIS detector at scales larger than 1 '', up to the size of the field of view, enabling Euclid to detect extended surface brightness structures below mu(lim) = 31 mag arcsec(-2) and beyond.Peer reviewe
Impact of Controlling the Site Distribution of Al Atoms on Catalytic Properties in Ferrierite-Type Zeolites
Zeolites with the ferrierite (FER) topology are synthesized using a combination of tetramethylammonium
(TMA) cations with differently sized cyclic amines (pyrrolidine (Pyr), hexamethyleneimine (HMI), and 1,4-
diazabicyclo[2.2.2]octane (DAB)). Using these organic structure-directing agents (SDAs), low Si/Al ratios
and concentrated synthesis mixtures favor the crystallization of FER materials. Increasing the size of the
cyclic amine or decreasing the aluminum content leads to the crystallization of other phases or the creation
of excessive amounts of connectivity defects. TMA cations play a decisive role in the synthesis of the FER
materials, and their presence allows the use of HMI to synthesize FER. Proton MAS NMR is used to quantify
the accessibility of pyridine to acid sites in these FER samples, where it is found that the FER + HMI + TMA
sample contains only 27% acid sites in the 8-MR channels, whereas FER + Pyr and FER + Pyr + TMA
contain 89% and 84%, respectively. The constraint index (CI) test and the carbonylation of dimethyl ether
(DME) with carbon monoxide are used as probe reactions to evaluate how changes in the aluminum distribution
in these FER samples affect their catalytic behavior. Results show that the use of Pyr as an SDA results in
the selective population of acid sites in the 8-MR channels, whereas the use of HMI generates FER zeolites
with an increased concentration of acid sites in the 10-MR channels
Epidemics in partially overlapped multiplex networks
Many real networks exhibit a layered structure in which links in each layer
reflect the function of nodes on different environments. These multiple types
of links are usually represented by a multiplex network in which each layer has
a different topology. In real-world networks, however, not all nodes are
present on every layer. To generate a more realistic scenario, we use a
generalized multiplex network and assume that only a fraction of the nodes
are shared by the layers. We develop a theoretical framework for a branching
process to describe the spread of an epidemic on these partially overlapped
multiplex networks. This allows us to obtain the fraction of infected
individuals as a function of the effective probability that the disease will be
transmitted . We also theoretically determine the dependence of the epidemic
threshold on the fraction of shared nodes in a system composed of two
layers. We find that in the limit of the threshold is dominated by
the layer with the smaller isolated threshold. Although a system of two
completely isolated networks is nearly indistinguishable from a system of two
networks that share just a few nodes, we find that the presence of these few
shared nodes causes the epidemic threshold of the isolated network with the
lower propagating capacity to change discontinuously and to acquire the
threshold of the other network.Comment: 13 pages, 4 figure
Genome-wide scan for five brain oscillatory phenotypes identifies a new qtl associated with theta eeg band
Brain waves, measured by electroencephalography (EEG), are a powerful tool in the investigation of neurophysiological traits and a noninvasive and cost-effective alternative in the diagnostic of some neurological diseases. In order to identify novel Quantitative Trait Loci (QTLs) for brain wave relative power (RP), we collected resting state EEG data in five frequency bands (d, ¿, a, ß1, and ß2) and genome-wide data in a cohort of 105 patients with late onset Alzheimer’s disease (LOAD), 41 individuals with mild cognitive impairment and 45 controls from Iberia, correcting for disease status. One novel association was found with an interesting candidate for a role in brain wave biology, CLEC16A (C-type lectin domain family 16), with a variant at this locus passing the adjusted genome-wide significance threshold after Bonferroni correction. This finding reinforces the importance of immune regulation in brain function. Additionally, at a significance cutoff value of 5 × 10-6, 18 independent association signals were detected. These signals comprise brain expression Quantitative Loci (eQTLs) in caudate basal ganglia, spinal cord, anterior cingulate cortex and hypothalamus, as well as chromatin interactions in adult and fetal cortex, neural progenitor cells and hippocampus. Moreover, in the set of genes showing signals of association with brain wave RP in our dataset, there is an overrepresentation of loci previously associated with neurological traits and pathologies, evidencing the pleiotropy of the genetic variation modulating brain function.This project is supported by “European Commission” and “European Regional Development Fund” under the project “Análisis y correlación entre el genoma completo y la actividad cerebral para la ayuda en el diagnóstico de la enfermedad de Alzheimer” (Project 1317_AD-EEGWA), (Cooperation Programme INTERREG V-A Spain-Portugal POCTEP 2014–2020) and the COMPETE 2020-Operacional Programme for Competitiveness and Internationalisation (POCI), Portugal 2020. Portuguese funds are supporting this work through FCT-Fundação para a Ciência e a Tecnologia/Ministério da Ciência, Tecnologia e Inovação in the framework of the project “Institute for Research and Innovation in Health Sciences” (POCI-01-0145-FEDER-007274). SM, AML, NP and IG are funded by FCT: CEECIND/00684/2017, IF/01262/2014, SFRH/BPD/97414/2013 and CEECIND/02609/2017, respectively. MA is funded by the Grant RYC-2015-18241 from the Spanish Government. Spanish funds are supporting this work through “Ministerio de Ciencia e Innovación–Agencia Estatal de Investigación” and “European Regional Development Fund” under project PGC2018-098214-A-I00 and by “CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN)” through “Instituto de Salud Carlos III” co-funded with “European Regional Development Fund” funds
The correlation between immune subtypes and consensus molecular subtypes in colorectal cancer identifies novel tumour microenvironment profiles, with prognostic and therapeutic implications
Background
Solid tumour growth is the consequence of a complex interplay between cancer cells and their microenvironment. Recently, a new global transcriptomic immune classification of solid tumours has identified six immune subtypes (ISs) (C1–C6). Our aim was to specifically characterise ISs in colorectal cancer (CRC) and assess their interplay with the consensus molecular subtypes (CMSs).
Methods
Clinical and molecular information, including CMSs and ISs, were obtained from The Cancer Genome Atlas (TCGA) (N = 625). Immune cell populations, differential gene expression and gene set enrichment analysis were performed to characterise ISs in the global CRC population by using CMSs.
Results
Only 5 ISs were identified in CRC, predominantly C1 wound healing (77%) and C2 IFN-γ dominant (17%). CMS1 showed the highest proportion of C2 (53%), whereas C1 was particularly dominant in CMS2 (91%). CMS3 had the highest representation of C3 inflammatory (7%) and C4 lymphocyte depleted ISs (4%), whereas all C6 TGF-β dominant cases belonged to CMS4 (2.3%). Prognostic relevance of ISs in CRC substantially differed from that reported for the global TCGA, and ISs had a greater ability to stratify the prognosis of CRC patients than CMS classification. C2 had higher densities of CD8, CD4 activated, follicular helper T cells, regulatory T cells and neutrophils and the highest M1/M2 polarisation. C2 had a heightened activation of pathways related to the immune system, apoptosis and DNA repair, mTOR signalling and oxidative phosphorylation, whereas C1 was more dependent of metabolic pathways.
Conclusions
The correlation of IS and CMS allows a more precise categorisation of patients with relevant clinical and biological implications, which may be valuable tools to improve tailored therapeutic interventions in CRC patients.This work was funded by projects DTS15/00157 , PI16/01827 and CIBER-ONC CB16/12/00442 from the Instituto de Salud Carlos III ( Ministry of Economy, Industry and Competitiveness, Spain ) and cofunded by the European Regional Development Fund (ERDF, European Union), and approved by the Ethics Committee or our Institution. BS is funded by AECC (Spain). MCR is funded by Instituto de Salud Carlos III and SEOM (Spain) CCP and BRC are funded by CAM (Programa de Empleo Juvenil (YEI)
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