Imatge de diagramació Imatge de diagramació Imatge de diagramació Imatge de diagramació
Logo Universitat de Barcelona

Facultat de Física

Imatge de diagramaci�
Inici Facultat Inici UB   
Imatge de diagramació
Agenda/Conferències i seminaris Imatge de diagramació
Imatge de diagramació Imatge de diagramació
Imatge de diagramació Imatge de diagramació Imatge de diagramació
Imatge de diagramació

 
 
   

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 29 de Març de 2017, a les 14:30h

Seminari del Dep. de Física Aplicada

Títol: Recent Advancement in Land Surface Modeling and its Impacts on Weather and Climate Simulations
Conferenciant: Few Chen National Center For Atmospheric Research, Boulder, CO, USA
Abstract:

One outstanding challenge in predicting weather and simulating regional climate is to accurately represent the land-atmosphere interactions cross various temporal and spatial scales, given the tremendous heterogeneity in land surfaces. We will report recent enhancement in land-surface models in the Weather Research and Forecast (WRF) model and their impacts in numerical weather prediction and regional climate simulations. Those enhancement include: 1) implementation and evaluation of the new Noah with multiple-physics (Noah-MP) land model. Results of evaluating the ability to simulate the seasonal evolution of snowpack in complex terrains by six land surface models will be discussed; 2) modifications to the WRF-Urban including hydrological enhancements, green-roof parameterization, and new urban-parameter data set, a new mosaic approach to treat land-use heterogeneity in highly urbanized regions, and urban heat-island mitigation modeling; and 3) development of crop-growth models that are intended to simulate phenological development, growth and yield formation from emergence until maturity using crop genetic properties, weather, and soil conditions following methods developed and adapted in the agriculture communities. We will discuss effects of land-atmosphere interactions in numerical weather prediction and regional climate simulations, and other applications of the above new modeling capabilities.

Lloc: Aula A23 M Aulari Facultat de Física
Contacte: rosa@am.ub.es
Web:

Facultat de Física, Dijous 30 de Març de 2017, a les 11:00h

Confèrencia de l'Institut de Nanociència i Nanotecnologia

Títol: Unique Science of Simple Oxides
Conferenciant: Prof. Ivan K. Schuller (Physics Department and Center for Advanced Nanoscience, UCSD-La Jolla, California 92093, USA)
Abstract:

This presentation will describe the static and dynamical properties of strongly correlated nanostructured oxides, which exhibit metal-insulator transitions. These materials when reduced to the nanoscale exhibit interesting properties such as avalanches, unique response to disorder and critical slowing down in their fast time dependence.

Lloc: Eduard Fontseré
Contacte: isaborit@ub.edu
Web: http://www.ub.edu/in2ub/index.php?lang=ca

Facultat de Física, Dijous 30 de Març de 2017, a les 14:00h

Seminari del Dep. de Física Quàntica i Astrofísica

Títol: Commensurate lock-in in holographic non-homogeneous lattices
Conferenciant: Tomás Andrade (University of Oxford)
Abstract:

We will consider the spontaneous formation of striped structures in a holographic model which possesses explicit translational symmetry breaking, dual to an ionic lattice with spatially modulated chemical potential. By studying the marginal modes which drive the transition to the stripped phase, we will discover that there is a commensurate lock-in between the spontaneous stripes and the underlying ionic lattice, which takes place when the amplitude of the lattice is large enough. We will also discuss some non-linear solutions which we expect to be the end points of such instabilities.

Lloc: Aula 507
Contacte: hofer@fqa.ub.edu
Web:

Facultat de Física, Divendres 31 de Març de 2017, a les 12:00h

Seminari del Dep. de Física Quàntica i Astrofísica

Títol: Jet substructure modifications in heavy-ion collisions
Conferenciant: Konrad Tywoniuk (CERN)
Abstract:

Significant experimental and theoretical activity at the LHC is dedicated to the study of an elusive state of matter, the quark-gluon plasma, created in head-on heavy-ion collisions. This plasma has been called the most perfect fluid given its small shear viscosity-to-entropy ratio. Measurements of fully reconstructed jets in these collisions allow to study new aspects of this exotic state via its coupling to perturbative degrees of freedom. We discuss how energetic colour charges propagate in a quark-gluon plasma and extend the previously known formalism to compute energy-loss of independent partons to treat neighbouring partons within the same jet. This extension accounts for the coherent structure of jet fragmentation and implies subtle modifications of the substructure. As a concrete application, we discuss the expected medium-modification of the jet splitting probability that is measured using the SoftDrop procedure.

Lloc: Aula 507
Contacte: hofer@fqa.ub.edu
Web:

Facultat de Física, Dimecres 05 de Abril de 2017, a les 11:30h

Seminari del Dep. de Física de la Matèria Condensada

Títol: PT-Symmetric Quantum Phenomena in Photonics and Materials
Conferenciant: Dr. Avadh Saxena (Los Alamos National Laboratory)
Abstract:

Parity-time or PT-symmetric quantum mechanics has emerged as a field in which non-Hermitian systems can give rise to real eigenvalues below a threshold value of a certain parameter. PT symmetry is essentially equivalent to spatially balanced loss and gain in a physical system. PT symmetry has now been realized in photonic waveguides as well as in electronic and magnetic materials. We will illustrate the unusual consequences of PT symmetry by two examples. First, we consider a complex photonic lattice by placing PTsymmetric
dimers at the Kagome lattice points. This lattice is a two-dimensional network of corner-sharing triangles. Each dimer represents a pair of strongly coupled waveguides.
The frustrated coupling between waveguide modes results in a dispersionless flat band comprising spatially localized modes. For a balanced arrangement of gain and loss on
each dimer, up to a critical value of the gain/loss parameter the system exhibits a PT-symmetric phase. The beam evolution in the waveguide array leads to an oscillatory
rotation of the optical power. We observe local chiral structures with a narrow beam excitation. In the second example we extend the Jarzynski equality to the case of PTsymmetric quantum thermodynamics through a simple example of two coupled waveguides. We find that the phase transition between the regimes of unbroken and broken PT symmetry is thermodynamically inhibited.

Lloc: Aula Pere Pascual
Contacte: toni@ecm.ub.edu
Web:

Facultat de Física, Dijous 06 de Abril de 2017, a les 12:30h

Confèrencia de l'Institut de Ciències del Cosmos

Títol: Proxima b: small planets around red dwarfs and the search for life beyond the Solar system
Conferenciant: Guillem Anglada-Escudé (Queen Mary University of London)
Abstract:

The existence of Proxima b -a possibly terrestrial planet in the habitable zone of the nearest star to the Sun- is a lucky concidence but not an event of cosmic fortune. Red dwarf stars that cannot be seen via naked eye are the most common stars in the Galaxy (about 70% of them) and detecting small, rocky, temperate and potentially habitable planets is way easier than around more massive stars like our Sun. I will put the discovery of Proxima b in the context of exoplanet detection and what we know in terms of the galactic abundance of planets around these stars. I will review the state of the art of the Doppler method in more detail, which is one of the two techniques leading to the discovery of the nearest red Earths. The smallness of the star also means that the planet-star contrast is better for potential follow-up studies such as atmospheric characterization and future attempts of directly imaging it. Looking into the future, the existence of terrestrial planets so close to our Sun has renewed the interest on advanced concepts to obtain direct images of them, and even sending interstellar probes within the next century.

Lloc: Aula Magna Enric Casassas
Contacte: secretariacientifica@icc.ub.edu
Web: http://icc.ub.edu/activity/902

Facultat de Física, Divendres 07 de Abril de 2017, a les 11:00h

Confèrencia del Dep. de Física Aplicada

Títol: Laser induced forward transfer of living cells using femtosecond laser pulses
Conferenciant: J. Zhang and H. Huber (Lasercenter, Munich University of Applied Sciences)
Abstract:

Laser induced forward transfer (LIFT) has been used in recent years for the rapid 3D-bioprinting of cells. Because of the high transfer rates and superior cell survival rates, this technique has great potential for tissue engineering applications. Here we apply a method developed by Prof. Serra and his group at the Universidad de Barcelona for the rapid, laser induced transfer of mammalian cells, which does not require any sacrificial inorganic material layer for laser pulse absorption. Instead, we focus an ultra-short (fs) laser pulse (λ= 1030 nm, 400 fs, few μJ) directly underneath the gel surface, to induce a rapidly expanding cavitation bubble, which generates a jet of material, transferring cell-laden hydrogel from a gel/cell reservoir to an acceptor stage. With this new method we demonstrated that well-defined and uniform micro-droplets of cell-laden hydrogel could be reproducible and controllable transferred with high spatial resolution. Most of cells survived the transfer and maintained the ability of cell proliferation.

Lloc: Seminari Física Aplicada (Room 526)
Contacte: pserra@ub.edu
Web:

Facultat de Física, Divendres 07 de Abril de 2017, a les 12:00h

Seminari del Dep. de Física de la Matèria Condensada

Títol: CELL MECHANICAL PROPERTIES AS MARKERS OF AGING AND DISEASE
Conferenciant: Paola Costelli (Department of Clinical and Biological Science, University of Torino, Italy)
Abstract:

Biological processes such as cell proliferation, differentiation, migration and
contraction are strictly related to intrinsic cell mechanical properties. The other way round,
aging, diseases and drug exposure have been shown to impinge on mechanical properties
of normal as well as tumor cells. As an example, differences in mechanical properties
between breast cancer cells and their normal counterpart have been reported. Similarly,
deformability is different comparing tumor cells characterized by an invasive phenotype to
normal cells or to cells that have not yet acquired the invasive capacity.
Mechanical properties become even more important when considering contractile
cells/tissues, with particular reference to the skeletal muscle. In this regard, both tone and
mechanical properties of muscles and tendons change with aging. In particular, muscle
tensile stiffness increases while elasticity decreases. Such changes are also associated
with reduced muscle mass (sarcopenia), mainly due to degradation of contractile proteins,
that likely contributes to the modulations observed in mechanical properties.
Along this line, the correlation of modifications of mechanical properties with
alterations of biological processes could be relevant in order to set up protocols useful for
the early identification of different pathological states.

Lloc: Aula Seminari 3.20, Dept. Física de la Matèria Condensada, 3rd floor of Physics Building
Contacte: fritort@gmail.com
Web: http://ffn.ub.es/ritort/news-activities/