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El límit per poder anunciar en paper seminaris i conferències en els ascensors és el divendres a les 12 hores de la setmana anterior. Amb posterioritat a aquesta data el seminari o conferència quedarà només recollit al web de la Facultat. Aleshores la publicitació en paper serà responsabilitat dels organitzadors.



Facultat de Física, Dimecres 20 de Setembre de 2017, a les 14:00h

Seminari del Dep. de Física Quàntica i Astrofísica

Títol: Remarks on holographic complexity and singularities
Conferenciant: José L. F. Barbón
Abstract:

I will describe some work in progress attempting to define a cuasilocal notion of holographic complexity for space like singularities. I will discuss the general conceptual framework and a number of examples.

Lloc: Aula 507 (Pere Pascual)
Contacte: vicente.atal@icc.ub.edu
Web:

Facultat de Física, Dijous 21 de Setembre de 2017, a les 12:00h

Confèrencia de l'Institut de Ciències del Cosmos

Títol: Equilibrium and Dimensionality in Chemical Evolution
Conferenciant: David H. Weinberg (Ohio State University)
Abstract:

I will discuss insights from analytic and numerical models of galactic chemical evolution and observations of Milky Way elemental abundances from the SDSS APOGEE surveys. Under generic assumptions, the abundances and abundance ratios in fully mixed one-zone chemical evolution models approach an equilibrium in which element production is balanced by depletion of heavy elements by star formation and outflows.
A stellar population can be metal-poor either because it has not yet evolved to equilibrium or because high outflow efficiency makes the equilibrium abundance itself low. Sudden transitions in a system can produce temporary boosts in alpha-to-iron ratios and other surprising behavior such as backward evolution of a stellar population from high metallicity to low metallicity. I will discuss applications of these ideas to understanding the distribution of stars in (alpha,iron,age)-space through the Milky Way disk, the origin of scatter in abundance ratios and dimensionality of the stellar distribution in chemical abundance space, supernova yields, and whether the Milky Way has a galactic wind at the present day.

Lloc: Aula Magna Enric Casassas
Contacte: secretariacientifica@icc.ub.edu
Web: http://icc.ub.edu/activity/903

Facultat de Física, Dijous 21 de Setembre de 2017, a les 15:30h

Seminari de l'Institut de Ciències del Cosmos

Títol: New results on BAO cosmology measurements using the Lya forest at z~2.3, and future prospects
Conferenciant: Nicolás Busca / Nicholas Ross
Abstract:

Programme:

15:30: Nicolás Busca (APC, Université Paris-Diderot, Paris):
"New results on BAO cosmology measurements using the Lya forest at z~2.3, and future prospects".

16:15: Nicholas Ross (Institute of Astronomy, University of Edinburgh):
"Opportunities for exploring the physics and evolution of quasars and galaxies: the case of Extremely Red Quasars".

17:00: General discussion on upcoming opportunities from large-scale astronomical surveys.
A challenge for the future is to develop efficient methods for a combined use of the large data sets from a wide variety of surveys using different observational techniques (e.g, DESI, DES, WEAVE, JPAS, GAIA, LOFAR, LSST, CMB surveys...), to learn about a broad range of fundamental questions in astrophysics and cosmology: galaxy evolution, dark matter, dark energy, LIGO sources, cosmological primordial perturbations... Everyone is welcome to participate and share ideas and comments on recent science results.

Lloc: Aula Pere Pascual (507)
Contacte: jmiralda@fqa.ub.edu
Web: http://icc.ub.edu/activity/1028

Facultat de Física, Divendres 22 de Setembre de 2017, a les 12:00h

Seminari del Dep. de Física Quàntica i Astrofísica

Títol: Holographic models and compact stars
Conferenciant: Carlos Hoyos
Abstract:

Matter at the core of massive neutron stars can reach densities that are beyond the regime of validity of first principles approaches to QCD. As matter at those densities is expected to be strongly coupled, the gauge/gravity duality may be an useful tool to determine its thermodynamic and transport properties. We explore the feasibility of using holographic models to describe deconfined matter in compact stars

Lloc: Aula 507
Contacte: vicente.atal@icc.ub.edu
Web:

Facultat de Física, Dijous 28 de Setembre de 2017, a les 12:00h

Seminari del Dep. de Física de la Matèria Condensada

Títol: Single-molecule investigation and modeling of target recognition by CRISPR-Cas complexes
Conferenciant: Ralf Seidel (Leipzig University, Germany)
Abstract:

The recently discovered CRISPR-Cas enzymes are promising tools in biotechnology and medicine. Central part of these enzyme systems are large protein complexes harboring a short RNA. The RNA promotes recognition of complementary nucleic acid targets by base pairing. The target recognition is, however, highly promiscuous, such that multiple mispairs between RNA and target strand are allowed. This causes technologically undesired off-target binding. Here we investigate the recognition of off-target sites by the CRISPR-Cas surveillance complex Cascade using single-DNA twisting experiments. This allows us to resolve the dynamics of the RNA base-pairing with the target. We find that the target recognition is a dynamic zipping process between RNA and DNA. Upon reaching a mismatch site, the zipping stalls and the zipper intermediate frequently collapses. Eventually thermal fluctuations allow to overcome single mismatches. Upon full zipping of the RNA along the target, a conformational change within the effector complex is triggered that causes DNA degradation. Thus, the complex acts simply as a guard that verifies whether the zipping was successful. Based on these observations we developed a random walk model that can quantitatively describe the dynamics of the target recognition process.

Lloc: Aula Seminari 3.20
Contacte: fritort@gmail.com
Web: http://ffn.ub.es/ritort/news-activities/

Facultat de Física, de Dijous 19 de Octubre de 2017 a Divendres 20 de Octubre de 2017, a les --h

Workshop del Dep. de Física de la Matèria Condensada

Títol: Workshop, Avalanches and Large Events
Conferenciant: Didier Sornette, Joaquin Marro, Gunnar Pruessner & Alvaro Corral
Abstract:

Workshop coorgantizat conjuntament amb l\'UBICS (Universitat de Barcelona, Institute of Complex Systems)

19/10 11:30 Didier Sornette (ETH-Zurich)
Dragon-kings: extreme risk events, prediction and control

19/10 15:00 Joaquin Marro (Universidad de Granada)
Mind and Phase Transitions

20/10 10:00 Gunnar Pruessner (Imperial College)
Avalanching and correlations in Self-Organised Criticality

20/10 11:30 Alvaro Corral (CRM, Bellaterra)
Phase transition and event-size distribution in finite-size random walks and branching processes

Si us plau, els interessats en assistir, registreu-vos a la pàgina web.



Lloc: Sala de Graus, Eduard Fontserè
Contacte: eduard@fmc.ub.edu
Web: http://ubics.ub.edu/workshop_avalanches/

Facultat de Física, de Dilluns 23 de Octubre de 2017 a Dijous 26 de Octubre de 2017, a les h

Curs de l'Institut de Ciències del Cosmos

Títol: ICCUB School, Barcelona: Hot Topics in Cosmology
Conferenciant:
Abstract:

This school is addressed to Ph.D students and postdocs in theoretical physics, with a strong research interest in Cosmology.

The goal of the school is to highlight a few selected topics, which are currently receiving a lot of interest in the scientific community, and to give the tools to young researchers to contribute to those fields.

In particular the school will be devoted to four topics:
- Gravitational Waves
- Primordial Black Holes in Cosmology
- Cosmic Microwave Background (CMB) and Spectral Distortions
- Axions

Lloc: Sala de Graus Eduard Fontserè, Facultat de Física
Contacte: secretariacientifica@icc.ub.edu
Web: http://icc.ub.edu/congress/ICCUBschool/

Facultat de Física, Dilluns 23 de Octubre de 2017, a les 12:00h

Seminari de l'Institut de Ciències del Cosmos

Títol: The Alleged Small-Scale Problems of LambdaCDM
Conferenciant: Julio Navarro (University of Victoria, Canada)
Abstract:

The Lambda Cold Dark Matter (LCDM) framework successfully accounts for observational constraints on large (> 1 Mpc) scales, from the clustering of galaxies to the angular dependence of the Cosmic Microwave Background to the structure and matter content of galaxy clusters. On the scale of individual galaxies and, in particular, of dwarf systems much fainter than the Milky Way, a number of apparent conflicts with LCDM expectations have been reported. These have prompted the consideration of a number of radical modifications to LCDM, such as the possibility that dark matter might be "self-interacting", or that it might not be “cold”. I will review the status of these alleged problems and will report on recent work that reevaluates the observational evidence and reexamines the role of systematic uncertainties in the comparison between observation and model predictions. In particular, I will propose a possible resolution to the “cusp vs core” problem that requires no cores; an explanation for the mass discrepancy-acceleration relation that requires no changes to the mass profile of LCDM halos; and a plausible origin for the enigmatic population of galaxies inhabiting “extremely cold” dark matter halos, such as the recently discovered Crater 2 satellite.

Lloc: Aula 507 (Pere Pascual)
Contacte: jmiralda@fqa.ub.edu
Web: http://icc.ub.edu/activity/1017