Testing strong gravity with gravitational waves and Love numbers

The LIGO observation of GW150914 has inaugurated the gravitational-wave astronomy era and the possibility of testing gravity in extreme regimes. While distorted black holes are the most convincing sources of gravitational waves, similar signals might be produced also by other compact objects. In particular, we discuss what the gravitational-wave ringdown could tell us about the nature of the emitting object, and how measurements of the tidal Love numbers could help us in understanding the internal structure of compact dark objects

First-passage times in multi-scale random walks: the impact of movement scales on search efficiency

An efficient searcher needs to balance properly the tradeoff between the exploration of new spatial areas and the exploitation of nearby resources, an idea which is at the core of scale-free L\'evy search strategies. Here we study multi-scale random walks as an approximation to the scale- free case and derive the exact expressions for their mean-first passage times in a one-dimensional finite domain. This allows us to provide a complete analytical description of the dynamics driving the asymmetric regime, in which both nearby and faraway targets are available to the searcher. For this regime, we prove that the combination of only two movement scales can be enough to outperform both balistic and L\'evy strategies. This two-scale strategy involves an optimal discrimination between the nearby and faraway targets, which is only possible by adjusting the range of values of the two movement scales to the typical distances between encounters. So, this optimization necessarily requires some prior information (albeit crude) about targets distances or distributions. Furthermore, we found that the incorporation of additional (three, four, ...) movement scales and its adjustment to target distances does not improve further the search efficiency. This allows us to claim that optimal random search strategies in the asymmetric regime actually arise through the informed combination of only two walk scales (related to the exploitative and the explorative scale, respectively), expanding on the well-known result that optimal strategies in strictly uninformed scenarios are achieved through L\'evy paths (or, equivalently, through a hierarchical combination of multiple scales)

Characterising protein arginine methylation in glioblastoma cell lines : implications for brain cancer

Protein arginine methylation is a post-translational modification that plays important roles in cellular signalling, transcription and RNA splicing and transport. The enzymes responsible for arginine methylation, protein arginine methyltransferases (PRMTs), have been reported to be aberrantly expressed in a variety of cancers, including breast, lung, bladder, prostate, ovarian and mantle cell lymphoma. It has become evident that arginine methylation is also a regulator of the cell cycle and aberrant expression of PRMTs contributes to deregulation of the cell cycle, contributing to carcinogenesis. Grade IV Glioblastoma multiforme is one of the most aggressive types of brain cancer. The 5- year survival rate for patients with brain cancer is only 20%. One of the difficulties in treating brain cancers is the low penetration of drugs across the blood-brain barrier. Hence, it is important to develop novel chemotherapy drugs to treat brain cancer which may be used alone or in combination with existing treatments. Protein arginine methylation is a potential target for novel drug development. In this thesis, protein arginine methylation in glioblastoma cell lines was characterised and the effect of the inhibition of two PRMTs was determined. The results showed, that although there were differences in the asymmetric and symmetric dimethylation of individual proteins, there were no consistent differences in the overall level of methylation between the control (non-cancerous) glial and glioblastoma (cancerous) cell lines. However, there were increases in the protein expression of the individual PRMTs in the glioblastoma cell lines when compared to the control glial cell line. Protein expression of PRMTs 1, 2, 5, 6 and 8 were all upregulated in A172 cells, PRMTs 5, 6 and 8 were upregulated in U87MG cells and PRMTs 5 and 6 were upregulated in T98G cells. A172 and T98G cells also had less protein expression of PRMT3 and PRMT1, respectively. Mass spectrometry analysis identified proteins with methylated arginine residues. Several proteins were identified to contain differentially methylated arginine residues in the four cell lines. Among these proteins, methylated arginine residues identified in the proteins, tubulin and Mortalin, have a functional significance which has been implicated in neurological malformations or disorders and cancer development, respectively, confirming that arginine methylation is an important regulator of cellular function. A recently described inhibitor of PRMTs 1 and 8 (trans-2, 3- dimethoxy-β- nitrostyrene) was used to determine the effect of PRMT1 and 8 inhibition in glial and glioblastoma cells. It was discovered that the PRMT1/8 inhibitor had a cytotoxic effect on control glial cells but a cytostatic effect on glioblastoma cells. The PRMT1/8 inhibitor caused a significant arrest in the S phase of the cell cycle in all cell lines except in the T98G cells. Cells treated with the PRMT1/8 inhibitor were more sensitive to UV exposure and took longer to recover according to cell number. This suggests that the PRMT1/8 inhibitor may be a potential novel therapeutic agent that could be used in combination with DNA damaging chemotherapy agents. In summary, protein arginine methylation and the expression of PRMTs differs between normal glial cells and glioblastoma cells. Control glial and glioblastoma cells were sensitive to the inhibition of PRMT1/8 in a PRMT1-dependent manner and this contributed to a delayed DNA damage response when the cells were exposed to UV. The newly gained insight supports that protein arginine methylation is a key regulator of carcinogenesis in glioblastoma and has identified PRMTs as a therapeutic target. The results may contribute to the future discovery of novel drugs that can be used for cancer treatment

Universities’ Entrepreneurship Education and Regional Development: a Stakeholders’ Approach

It is assumed that entrepreneurship education encourage the growth of new businesses, exploiting the entrepreneurial spirit within higher education sector. Additionally, entrepreneurship higher education is supposed to play a relevant role in the development of enterprising citizens and in the development regions through an ongoing process of knowledge creation and delivery. In this research we will explore what roles are attributed to entrepreneurship education in the literature with regard to regional development as well as the influence and relationship of the main intervening stakeholders. The aim is to present a conceptual model which integrate the contributions of both strands of literature and, at the same time, highlight the interplay between the several stakeholders involved in HEI’s entrepreneurship education and regional development.Entrepreneurship education, university, regional development, stakeholders

Magnetism and Electronic Correlations in Quasi-One-Dimensional Compounds

In this contribution on the celebration of the 80th birthday anniversary of Prof. Ricardo Ferreira, we present a brief survey on the magnetism of quasi-one-dimensional compounds. This has been a research area of intense activity particularly since the first experimental announcements of magnetism in organic and organometallic polymers in the mid 80s. We review experimental and theoretical achievements on the field, featuring chain systems of correlated electrons in a special AB2 unit cell structure present in inorganic and organic compounds

The Black's place in the city image: Afroeuropeans and urban representations in Europe

In this session, we will investigate the visibility/invisibility and the inclusion/exclusion of African populations and people of African descent, within the physical and imaginary borders of Europeans cities with a colonial history. Focusing on both the material and immaterial aspects of the image construction, we will engage in debates concerned with the involvement of African populations and their descendants in current urban representations.info:eu-repo/semantics/publishedVersio

Quantum oscillator and Kepler-Coulomb problems in curved spaces: deformed shape invariance, point canonical transformations, and rational extensions

The quantum oscillator and Kepler-Coulomb problems in $d$-dimensional spaces with constant curvature are analyzed from several viewpoints. In a deformed supersymmetric framework, the corresponding nonlinear potentials are shown to exhibit a deformed shape invariance property. By using the point canonical transformation method, the two deformed Schr\"odinger equations are mapped onto conventional ones corresponding to some shape-invariant potentials, whose rational extensions are well known. The inverse point canonical transformations then provide some rational extensions of the oscillator and Kepler-Coulomb potentials in curved space. The oscillator on the sphere and the Kepler-Coulomb potential in a hyperbolic space are studied in detail and their extensions are proved to be consistent with already known ones in Euclidean space. The partnership between nonextended and extended potentials is interpreted in a deformed supersymmetric framework. Those extended potentials that are isospectral to some nonextended ones are shown to display deformed shape invariance, which in the Kepler-Coulomb case is enlarged by also translating the degree of the polynomial arising in the rational part denominator.Comment: 32 pages, no figure; published versio