1,399 research outputs found
Reversal of terminal differentiation and control of DNA replication
DNA replication in mammalian cells occurs in discrete nuclear foci. Here we show that terminally differentiated myotubes can be induced to reenter S phase and show the same pattern of replication foci as cycling cells. We used this cellular system to analyze the interaction of cell cycle proteins with these foci in vivo. Cyclin A and cdk2, but not cyclin B1 and cdc2, were specifically localized at nuclear replication foci, just like the replication protein proliferating cell nuclear antigen. A potential target of cyclin A and cdk2 is the 34 kd subunit of replication protein A (RPA34). In contrast with the 70 kd subunit, which localizes to the foci, RPA34 was not detected at these replication sites, which may reflect a transient interaction. The specific localization of cyclin A and cdk2 at nuclear replication foci provides a direct link between cell cycle regulation and DNA replication
Aproximació a Vsévolod Meierhold. La teoria i la prà ctica teatral
Treballs Finals de Grau d'Història de l'Art, Facultat de Geografia i Història, Universitat de Barcelona, Curs: 2015-2016, Tutor: Enric Ciurans PeraltaAquest Treball Final de Grau es centra en la figura del teòric i director teatral rus Vsévolod Meierhold (1874-1940), i la seva trajectòria en el món escènic durant les primeres dècades del segle XX, a la Rússia revolucionà ria. L’esquema del treball seguirà una estructura basada en la cronologia, tot i que no sempre, començant per la seva etapa de formació fins a observar la influència que exerceix la seva tasca. També té la intenció d’incloure alguns punts de teoria a partir de la qual crearà la seva prà ctica escènica
Antoni Despuig i Dameto, el mapa de Mallorca (1784-1785) i la Societat d'Amics del PaĂs
El clérigo Antoni Despuig i Dameto (1745-1813), si no fue el autor, fue el responsable de uno de
los mapas de Mallorca más celebrados, grabado por Josep Muntaner en 1785. La iniciativa surgió
probablemente en el seno de la Sociedad EconĂłmica Mallorquina de Amigos del PaĂs. El artĂculo
hace una revisiĂłn de los posibles intervinientes y de algunas caracterĂsticas del documento como las
coordenadas, la escala (1:72.000 ca) y los datos referidos a caminos y poblaciones.The clergyman Antoni Despuig i Dameto (1745-1813), if he was not the author he was the person
in charge of one of the more celebrated maps of Majorca, burdened by Josep Muntaner in 1785. The
initiative arose probably in the bosom of the Sociedad EconĂłmica Mallorquina de Amigos del PaĂs. This
paper does a review of the possible interveners and of some characteristics of the document as the
coordinates, the scale (1:72.000 ca) and the information referred to ways and populations
William Shakespeare's mystery: the theories about his existence
Treballs Finals del Grau d'Estudis Anglesos, Facultat de Filologia, Universitat de Barcelona, Curs:
2017-2018, Tutor: Enric Montforte Rabascall[eng] William Shakespeare is known for being one of the most relevant writers in the history of English literature. His ability to write, his vocabulary and his knowledge of the world, among others, have made of his plays a treasure in the world’s literature of all times. His perfection in writing is precisely the reason why critics have questioned over time whether William Shakespeare was the real author of the plays attributed to him. Who was William Shakespeare? Or who was the author writing behind the name of William Shakespeare? Several Anti-Stratfordians, those who deny Shakespeare’s authorship, have suggested their candidates and have explained the reasons why they are totally plausible Shakespeares. Nonetheless, there are critics who remain faithful to the theory that William Shakespeare did exist and that the only real author of the plays attributed to him was Shakespeare himself. This paper focuses on these two points of view about William Shakespeare’s existence, trying to approach the truth about the authorship of Shakespeare’s plays.[cat] William Shakespeare Ă©s conegut per ser un dels autors mĂ©s rellevants de la història de la literatura anglesa. La seva habilitat en l’escriptura, el seu vocabulari i el seu coneixement del mĂłn, entre d’altres, han fet de les seves obres un tresor de la literatura universal de tots els temps. És, de fet, la genialitat de les seves obres la raĂł per la qual crĂtics s’han anat qĂĽestionant si realment William Shakespeare va escriure les obres que se li han atribuĂŻt. Qui va ser William Shakespeare? O qui va ser l’autor que va escriure darrera el nom de William Shakespeare? Alguns Anti-Stratfordians, que neguen l’autoria de Shakespeare, ja han suggerit els seus candidats i han explicat les raons per les quals aquests podrien ser perfectament Shakespeare. No obstant, hi ha crĂtics que segueixen fidels a la teoria de que William Shakespeare sĂ que va existir i que l’únic autor de les obres que se l’hi atribueixen Ă©s ell mateix. Aquest treball es centra en aquests dos punts de vista sobre l’existència de William Shakespeare, tractant d’aproximar-se a la veritat sobre l’autoria de les seves obres
Who is in and who is not? Determining the Gaia survey selection function
What is the probability that an astronomical object of certain properties enters the Gaia catalogue (or not)? The GaiaUnlimited project aims to enable the full potential of Gaia by characterising its survey selection function, as well as for different subsamples of the data, which are key ingredients in most statistical studies of the Milky Way. By comparing Gaia with deeper imaging from the Dark Energy Camera Plane Survey (DECaPS), we have developed an empirical model of the completeness in the Gaia pipeline, as a function only of the observed G magnitude and position over the sky, which accounts for both the effects of crowding and the complex Gaia scanning law. We also demonstrate the recipe to estimate the selection function of the stars present in a subsample of Gaia data, given that the subsample is completely contained in the Gaia parent catalogue, and how it can be extended to include the selection functions of other surveys (e.g. WEAVE, GALAH). Finally, we demonstrate the use of these selection functions by showing that the asymmetry in the Gaia-Sausage/Enceladus debris is merely due to selection effects
Detection, characterisation and use of open clusters in a Galactic context in a Big Data environment
[eng] Open clusters are groups of stars, gravitationally bound together, that were born from the same molecular cloud and, thus, share similar positions, kinematics, ages and metallicities. Traditional methods to detect open clusters rely in the visual inspection of regions of the sky to look for positional overdensities of stars, which then are checked to follow an isochrone pattern in a colour-magnitude diagram. The publication of the second Gaia data release, with more than 1.3 billion stars with parallax and proper motion measurements together with mean photometry in three broadbands, boosted the development of novel machine learning-based techniques to automatise the search for open clusters, using both the astrometric and photometric information. The characterised open clusters in the Galaxy are popular tracers of properties of the Galactic disc such as the structure and evolution of the spiral arms, or testbed for stellar evolution studies for instance, because their astrophysical parameters are estimated with greater precision than for field stars. Therefore, a good understanding of the open cluster population in the Milky Way is key for Galactic archaeology studies. Our aim for this thesis is to transform classical methodologies to detect different kinds of patterns from astronomical data, that mostly relies on visual inspection, to an automatic data mining procedure to extract meaningful information from stellar catalogues. We also aim to use the result of the application of machine learning techniques to Gaia data, in a broader Galactic context. We have developed a data mining methodology to blindly search for open clusters in the Galactic disc. First, we use a density-based clustering algorithm, DBSCAN, to search for overdensities in the five-dimensional astrometric parameter space in Gaia data. The deployment of the clustering step in a Big Data environment, at the MareNostrum supercomputer located in the Barcelona Supercomputing Center, prevents the search to be limited by computational limitations. Second, the detected overdensities are classified into mere statistical or physical overdensities using an artificial neural network trained to recognise the isochrone pattern that open cluster member stars follow in a colour-magnitude diagram. We estimate astrophysical parameters such as ages, distances and line-of-sight extinctions for the whole open cluster population using an artificial neural network trained on well-known open clusters. We use this additional information, together with radial velocities gathered from different space-based and ground-based surveys, to trace the Galactic spiral present-day structure using GaussianMixtureModels to associate the young (< 30 Myr) open clusters to their mother spiral arms. We also describe the spiral arms evolution during the last 80 Myr to provide new insights into the nature of the Milky Way spiral structure. The automatization of the open cluster detection procedure, together with its deployment in a Big Data environment, has resulted in more than 650 new open clusters detected with this methodology. The new UBC clusters (named after the University of Barcelona) represent one-third of the actual open clusters census (2017 objects with Gaia DR2 parameters), and it is the largest single contribution to the open cluster catalogue. We are able to add 264 young open clusters (< 30 Myr) to the 84 high-mass star- forming regions traditionally used to trace spiral arms, to increase the Galactocentric azimuth range where the Milky Way spiral arms are defined, and better estimate their present-day parameters. By analysing the age distribution of the open clusters across the Galactic spiral arms, and computing the spiral arms pattern speeds following the open clusters orbits from their birthplaces, we are able to disfavour classical density waves as the main mechanism for the formation of the Milky Way spiral arms, favouring a transient behaviour. This thesis has shown that the use of machine learning, with proper treatment of the computational resources, has a long journey ahead in a data-dominated future for Astronomy.[cat] Els cĂşmuls estel·lars oberts sĂłn conjunts d'estels, lligats gravitatòriament, nascuts al mateix nĂşvol molecular que tenen propietats similars. Aquests cĂşmuls sĂłn traçadors populars de la estructura del disc GalĂ ctic, com ara els braços espirals. El segon llançament de dades de Gaia, amb mĂ©s de 1300 milions d'estels, impossibilita la detecciĂł de cĂşmuls a partir de mètodes tradicionals degut al gran volum del catĂ leg. Per això, el desenvolupament de tècniques automĂ tiques per aquest fi ha crescut juntament amb el volums dels catĂ legs a analitzar. Hem desenvolupat una metodologia per a la cerca a cegues de cĂşmuls oberts al disc GalĂ ctic. Hem utilitzat un algoritme de clustering, DBSCAN, per trobar sobredensitats en l'espai astromètric de cinc dimensions de Gaia. La implementaciĂł del mètode de clustering a un entorn de Big Data, al superordinador MareNostrum, ens permet cercar cĂşmuls oberts basant-nos en les seves propietats fĂsiques. Les sobredensitats detectades s'identifiquen com a cĂşmuls oberts reals per mitjĂ d'una xarxa neuronal artificial que reconeix isòcrones en un diagrama de color-magnitud. L'automatitzaciĂł del procediment de detecciĂł amb l'Ăşs de tècniques de Big Data, ha resultat en mĂ©s de 650 nous cĂşmuls. Aquests nous cĂşmul representen un terç de la poblaciĂł actual, i Ă©s la contribuciĂł individual mĂ©s gran al catĂ leg. Hem pogut estimar les propietats fĂsiques dels cĂşmuls com distĂ ncia, edat i extinciĂł, fent servir una xarxa neuronal artificial entrenada sobre cĂşmuls coneguts. Fem servir aquesta informaciĂł, juntament amb mesures de velocitat radial, per traçar l'estructura espiral actual de la nostra GalĂ xia associant els cĂşmuls oberts mĂ©s joves (< 30 milions d'anys) al braç espiral on s'han format. Amb això, hem augmentat el nombre de traçadors de braços espirals, afegint 264 cĂşmuls joves als traçadors utilitzats tradicionalment. Això ens ha permès estimar millor els parĂ metres actuals d'aquests braços. Analitzant la distribuciĂł en edat dels cĂşmuls dins dels braços espirals, i calculant la velocitat en la que aquests braços es mouen a partir de l'orbita dels cĂşmuls, hem pogut desfavorir la teoria clĂ ssica d'ona de densitat com a mecanisme principal de formaciĂł de l'estructura espiral, trobant un comportament mĂ©s transitori dels braços
La Causa General. Repercusiones econĂłmicas y sociales de la Guerra Civil en las Islas Baleares
El present article ens proposa per primera vegada la descripciĂł de la documentaciĂł relativa a la Causa General aplicada a les Illes Balears. Iniciada el 1940 per la FiscalĂa General del Estado a travĂ©s de sumaris provincials en tot el territori espanyol, la Causa General pretenia conèixer la repressiĂł i violència exercida en zona republicana al llarg de la Guerra Civil amb diverses finalitats, com la propagandĂstica, per concedir ajuts als afectats i, lògicament, amb la intenciĂł d’exercir la repressiĂł que caracteritzĂ al règim franquista. L’autor ens facilita la possibilitat de conèixer aspectes econòmics i socials necessaris per l’estudi de la Guerra Civil i les seves conseqüències mĂ©s immediates a l’arxipèlag balear
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