210 research outputs found
Oxygen-neon rich merger during common envelope evolution
We conduct a population synthesis study of the common envelope evolution
(CEE) of a white dwarf (WD) and an asymptotic giant branch (AGB) star and find
that the potential number of type Ia supernovae (SNe Ia) from the core
degenerate (CD) and from the double degenerate (DD) scenarios are of the same
order of magnitude. For the CD scenario we consider cases where a carbon oxygen
rich (CO) AGB core and a CO WD merge during the CEE and leave a WD remnant with
a mass of >1.35Mo, and for the DD scenario we count surviving CO WD binary
systems that merge within a time of 10 Gyr. When either the AGB core or the WD
are oxygen neon rich (ONe) we assume that the outcome might be a peculiar SN
Ia. We find that the number of potential peculiar SNe Ia in the channels we
study, that do not include peculiar SNe Ia that involve helium WDs or helium
donors, is non-negligible, but less than the number of normal SNe Ia. If a SN
Ia or a peculiar SN Ia explosion takes place within about million year after
CEE, whether in the CD scenario or in the DD scenario, a massive circumstellar
matter is present at explosion time. Our results are compatible with the
suggestion that Chandrasekhar-mass SNe Ia mostly come from the CD scenario, and
sub-Chandrasekhar SNe Ia mostly come from the DD scenario.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical
Societ
Via pulchritudinis: respuesta de la iglesia a la crisis contemporánea
One of the most important challenges of Pastoral Theology nowadays is to study how to deliver the Truth to our public today. The world has lost its persuasive capacity, the “dictatorship of relativism” has taken its roots in every field. We are confronted to the rebirth of a “new religiosity” produced by the “emerging spiritualties”. Against this background, objections have been raised saying that the Church has no valid answers for our world today. Nevertheless, it is the Church that has actually the best means to answer the preoccupations of men today, who are, in fact, deprived of truth, beauty and clear thinking. Starting from the quest for God, through the beauty, this work analyzes the great pastoral hope of our times: the Via Pulchritudinis.En nuestros dĂas uno de los desafĂos más importantes de la teologĂa pastoral es el estudio de cĂłmo vehicular la Verdad para el pĂşblico contemporáneo. En un mundo donde los conceptos han perdido su capacidad persuasiva, la “dictadura del relativismo” se va implantando en todos los campos. Nos encontramos delante del surgimiento de una “nueva religiosidad”, fruto de “las espiritualidades emergentes”. En medio de este panorama, una de las principales objeciones que se le hace a la Iglesia CatĂłlica es que ella no tiene propuestas válidas para el mundo de hoy. Sin embargo es la Iglesia la que tiene en sus manos los mejores instrumentales para responder a las inquietudes del hombre actual, huĂ©rfano de verdad, de belleza, de claridad en el pensamiento. Partiendo de la bĂşsqueda de Dios por medio de la belleza, el presente trabajo analiza la gran esperanza pastoral de nuestros dĂas: la Via Pulchritudinis. 
Estudi del flux potencial al voltant de perfils amb finalitats docents
El projecte “Estudi del flux potencial al voltant de perfils amb finalitats docents” pretén,
principalment, modelitzar un conjunt de prĂ ctiques que puguin ser dutes a terme pels
alumnes de l’assignatura de mecà nica de fluids.
En primer lloc, es farà un estudi de la teoria de flux potencial. La idea és veure l’evolució
que té un fluid (en el nostre cas, aire) en el seu estat més senzill. Aquest estudi es
realitzarà al voltant d’un esglaó. Seguidament, es portarà l’estudi a un entorn d’anà lisi
numèric computacional. Aquà es podrà observar l’evolució que té el perfil escollit
anteriorment mitjançant un programa comercial de dinà mica de fluids computacional (CFD).
Es procedirà a l’obtenció de dades a través d’un flux potencial i també a través d’un flux el
més real possible.
En aquest punt es compararan les dades obtingudes entre la teoria de flux potencial, amb
les d’anà lisi numèric. Feta la comparació, es procedirà a l’accés del següent nivell del
projecte que és l’estudi d’un determinat perfil d’ala. En aquest nivell es continuarà amb l’ús
del programa de CFD i es farà una visualització de l’evolució d’un flux potencial i d’un flux
de caire real al voltant de l’esmentat perfil.
Finalment s’arribarà a l’últim nivell de projecte, que és l’obtenció de dades en un entorn
experimental. En aquesta part s’utilitzarĂ un perfil d’ala fĂsic amb la mateixa geometria que
l’estudiat anteriorment. Mitjançant un ventilador es recolliran una sèrie de dades de pressió
que ens serviran per corroborar les obtingudes prèviament en la simulació.
Amb la comparaciĂł de les dades obtingudes en aquests tres nivells, les prĂ ctiques
proporcionaran a l’alumne la informació necessà ria per arribar a entendre el motiu principal
dels mecanismes de generaciĂł de sustentaciĂł en un aviĂł
From a systems view to spotting a hidden island : A narrative review implicating insula function in alcoholism
Excessive use of alcohol promotes the development of alcohol addiction, but the understanding of how alcohol induced brain alterations lead to addiction remains limited. To further this understanding, we adopted an unbiased discovery strategy based on the principles of systems medicine. We used functional magnetic resonance imaging data from patients and animal models of alcohol addiction-like behaviors, and developed mathematical models of the 'relapse-prone' network states to identify brain sites and functional networks that can be selectively targeted by therapeutic interventions. Our systems level, non-local, and largely unbiased analyses converged on a few well-defined brain regions, with the insula emerging as one of the most consistent findings across studies. In proof-of-concept experiments we were able to demonstrate that it is possible to guide network dynamics towards increased resilience in animals but an initial translation into a clinical trial targeting the insula failed. Here, in a narrative review, we summarize the key experiments, methodological developments and knowledge gained from this complete round of a discovery cycle moving from identification of 'relapse-prone' network states in humans and animals to target validation and intervention trial. Future concerted efforts are necessary to gain a deeper understanding of insula function a in a state-dependent, circuit-specific and cell population perspective, and to develop the means for insula-directed interventions, before therapeutic targeting of this structure may become possible.Peer reviewe
Structural and functional, empirical and modeled connectivity in the cerebral cortex of the rat
[EN] Connectomics data from animal models provide an invaluable opportunity to reveal the complex interplay between structure and function in the mammalian brain. In this work, we investigate the relationship between structural and functional connectivity in the rat brain cortex using a directed anatomical network generated from a carefully curated meta-analysis of published tracing data, along with resting-state functional MRI data obtained from a group of 14 anesthetized Wistar rats. We found a high correspondence between the strength of functional connections, measured as blood oxygen level dependent (BOLD) signal correlations between cortical regions, and the weight of the corresponding anatomical links in the connectome graph (maximum Spearman rank-order correlation rho = 0.48). At the network-level, regions belonging to the same functionally defined community tend to form more mutual weighted connections between each other compared to regions located in different communities. We further found that functional communities in resting-state networks are enriched in densely connected anatomical motifs. Importantly, these higher-order structural subgraphs cannot be explained by lower-order topological properties, suggesting that dense structural patterns support functional associations in the resting brain. Simulations of brain-wide resting-state activity based on neural mass models implemented on the empirical rat anatomical connectome demonstrated high correlation between the simulated and the measured functional connectivity (maximum Pearson correlation rho = 0: 53), further suggesting that the topology of structural connections plays an important role in shaping functional cortical networks.This work was supported in part by the Spanish Ministerio de Economia y Competitividad (MINECO) and FEDER funds under grants BFU2015-64380-C2-1-R (S.C) and BFU2015-64380-C2-2-R (D.M.) and EU Horizon 2020 Program 668863-SyBil-AA grant (S.C.). S.C. acknowledges financial support from the Spanish State Research Agency, through the "Severo Ochoa" Programme for Centres of Excellence in R&D (ref. SEV-2013-0317). A. D.-P., was supported by grant FPU13/01475 from the Spanish Ministerio de Educacion, Cultura y Deporte (MECD). O.S. acknowledges support by the J.S. McDonnell Foundation (#220020387) and the National Institutes of Health (NIH R01 AT009036-01). We are also grateful to Andrea Avena-Koenigsberger and Begona Fernandez for their technical support.DĂaz-Parra, A.; Osborn, Z.; Canals Gamoneda, S.; Moratal, D.; Sporns, O. (2017). Structural and functional, empirical and modeled connectivity in the cerebral cortex of the rat. NeuroImage. 159:170-184. https://doi.org/10.1016/j.neuroimage.2017.07.046S17018415
RATT: RFID Assisted Tracking Tile. Preliminary results
© 2017 IEEE. Personal use of this material is permitted. PermissĂon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisĂng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.[EN] Behavior is one of the most important aspects of animal life. This behavior depends on the link between animals, their nervous systems and their environment. In order to study the behavior of laboratory animals several tools are needed, but a tracking tool is essential to perform a thorough behavioral study. Currently, several visual tracking tools are available. However, they have some drawbacks. For instance, when an animal is inside a cave, or is close to other animals, the tracking cameras cannot always detect the location or movement of this animal.
This paper presents RFID Assisted Tracking Tile (RATT), a tracking system based on passive Radio Frequency Identification (RFID) technology in high frequency band according to ISO/IEC 15693.
The RATT system is composed of electronic tiles that have nine active RFID antennas attached; in addition, it contains several overlapping passive coils to improve the magnetic field characteristics. Using several tiles, a large surface can be built on which the animals can move, allowing identification and tracking of their movements. This system, that could also be combined with a visual tracking system, paves the way for complete behavioral studies.Research supported in part by the Spanish Ministerio de Economia y Competitividad (MINECO) and FEDER funds under grants BFU2015-64380-C2-2-R and BFU2015-64380-C2-1-R. Santiago Canals acknowledges financial support from the Spanish State Research Agency, through the "Severo Ochoa" Programme for Centres of Excellence in R&D (ref. SEV-2013-0317). Dario R. Quinones is supported by grant Ayudas para la formacion de personal investigador (FPI) from Universitat Politecnica de Valencia.Quiñones, DR.; Cuevas-López, A.; Cambra-Enguix J.; Canals-Gamoneda, S.; Moratal, D. (2017). RATT: RFID Assisted Tracking Tile. Preliminary results. Proceedings Intenational Anual Conference of IEEE Engineering in Medicine and Biology Society. 4114-4117. https://doi.org/10.1109/EMBC.2017.8037761S4114411
Automatic positioning device for cutting three-dimensional tissue in living or fixed samples. Proof of concept
"© 2017 IEEE. Personal use of this material is permitted. PermissĂon from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertisĂng or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works."[EN] The study and analysis of tissues has always been an important part of the subject in biology. For this reason, obtaining specimens of tissue has been vital to morphological and functionality research. Historically, the main tools used to obtain slices of tissue have been microtomes and vibratomes. However, they are largely unsatisfactory. This is because it is impossible to obtain a full, three-dimensional structure of a tissue sample with these devices.
This paper presents an automatic positioning device for a three-dimensional cut in living or fixed tissue samples, which can be applied mainly in histology, anatomy, biochemistry and pharmacology. The system consists of a platform on which the tissue samples can be deposited, plus two containers. An electromechanical system with motors and gears gives the platform the ability to change the orientation of a sample. These orientation changes were tested with movement sensors to ensure that accurate changes were made.
This device paves the way for researchers to make cuts in the sample tissue along different planes and in different directions by maximizing the surface of the tract that appears in a slice.Research supported in part by the Spanish Ministerio de Economia y Competitividad (MINECO) and FEDER funds under grants BFU2015-64380-C2-2-R and BFU2015-64380-C2-1-R. Santiago Canals acknowledges financial support from the Spanish State Research Agency, through the "Severo Ochoa" Programme for Centres of Excellence in R&D (ref. SEV- 2013-0317). Dario Quinones is supported by grant Ayudas para la formacion de personal investigador (FPI) from Universitat Politecnica de Valencia. We are grateful to Begoña Fernández (Neuroscience Institute, Consejo Superior de Investigaciones CientĂficas - CSIC, Alicante, Spain) for her excellent technical assistance.Quiñones, DR.; PĂ©rez Feito, R.; GarcĂa Manrique, JA.; Canals-Gamoneda, S.; Moratal, D. (2017). Automatic positioning device for cutting three-dimensional tissue in living or fixed samples. Proof of concept. Proceedings Intenational Anual Conference of IEEE Engineering in Medicine and Biology Society. 1372-1375. https://doi.org/10.1109/EMBC.2017.8037088S1372137
Lysosomal degradation ensures accurate chromosomal segregation to prevent chromosomal instability
Lysosomes, as primary degradative organelles, are the end-point of different converging pathways including macroautophagy. To date, lysosome degradative function has been mainly studied in interphase cells, while their role during mitosis remains controversial. Mitosis dictates the faithful transmission of genetic material among generations, and perturbations of mitotic division lead to chromosomal instability, a hallmark of cancer. Heretofore, correct mitotic progression relies on the orchestrated degradation of mitotic factors, which was mainly attributed to ubiquitin-triggered proteasome-dependent degradation. Here, we show that mitotic transition does not only rely on proteasome-dependent degradation, as impairment of lysosomes increases mitotic timing and leads to mitotic errors, thus promoting chromosomal instability. Furthermore, we identified several putative lysosomal targets in mitotic cells. Among them, WAPL, a cohesin regulatory protein, emerged as a novel SQSTM1-interacting protein for targeted lysosomal degradation. Finally, we characterized an atypical nuclear phenotype, the toroidal nucleus, as a novel biomarker for genotoxic screenings. Our results establish lysosome-dependent degradation as an essential event to prevent chromosomal instability
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