Accretion and activity on the post-common-envelope binary RR~Cae

Current scenarios for the evolution of interacting close binaries - such as cataclysmic variables (CVs) - rely mainly on our understanding of low-mass star angular momentum loss (AML) mechanisms. The coupling of stellar wind with its magnetic field, i.e., magnetic braking, is the most promising mechanism to drive AML in these stars. There are basically two properties driving magnetic braking: the stellar magnetic field and the stellar wind. Understanding the mechanisms that drive AML therefore requires a comprehensive understanding of these two properties. RRCae is a well-known nearby (d=20pc) eclipsing DA+M binary with an orbital period of P=7.29h. The system harbors a metal-rich cool white dwarf (WD) and a highly active M-dwarf locked in synchronous rotation. The metallicity of the WD suggests that wind accretion is taking place, which provides a good opportunity to obtain the mass-loss rate of the M-dwarf component. We analyzed multi-epoch time-resolved high-resolution spectra of RRCae in search for traces of magnetic activity and accretion. We selected a number of well-known activity indicators and studied their short and long-term behavior. Indirect-imaging tomographic techniques were also applied to provide the surface brightness distribution of the magnetically active M-dwarf, and reveals a polar feature similar to those observed in fast-rotating solar-type stars. The blue part of the spectrum was modeled using a atmosphere model to constrain the WD properties and its metal enrichment. The latter was used to improve the determination of the mass-accretion rate from the M-dwarf wind. The presence of metals in the WD spectrum suggests that this component arises from accretion of the M-dwarf wind. A model fit to the WD gives Teff=(7260+/-250)K and logg=(7.8+/-0.1) dex with a metallicity of =(-2.8+/-0.1)dex, and a mass-accretion rate of dotMacc=(7+/-2)x1e-16Msun/yr.Comment: 14 pages, 7 Figures, 6 Table

The impact of the cytoskeleton dynamics on immune responses

Immune cells are susceptible to a variety of external stimuli that triggers cell surface receptors, leading to activation of intracellular proteins and changes in the actin cytoskeleton. The Rho-GTPases are a family of proteins that regulate several aspects of actin polymerization. They take part in an intricate network of other proteins and can therefore have a direct or indirect role in several cell functions. In this study I aimed to define the role of the Rho-GTPases Cdc42 and Rac2, as well as the effector proteins WASp and N-WASp in the adaptive immune system. In paper I the aim was to dissect the particular contribution of WASp-deficiency to the induction of skin pathology in Wiskott-Aldrich syndrome patients, using mouse models. Our study showed that WASp-deficient dendritic cells accumulate in the skin; were able to induce an increase in cross-presentation of exogenous antigen and therefore increased CD8+ T cell proliferation and activation in vivo and in vitro. This was caused by increased expression of Rac2 in the cytoplasm, which regulates the phagosomal pH and promotes loading of antigen on MHC class I molecules. In paper II we aimed to understand the role of Cdc42 for B cell activation using a mouse where we deleted Cdc42 conditionally in mature B cells. Mice with Cdc42-deficient B cells showed reduced marginal zone and follicular B cell numbers. Immunized mice had reduced germinal center B cells associated with reduced specific antibody titers in serum. In vitro assays revealed less spreading on antibody-coated surfaces and a skewed CD4+ T cell activation towards more production of IFN and less IL-2. In paper III we studied the combined contribution of WASp and N-WASp deficiency in B cells. A WASp KO mouse where N-WASp was conditionally deleted only in B cells (cDKO) was used. Compared to WT and WASp KO mice, the cDKO mouse had a large reduction in marginal zone B cells as well as decreased marginal zone B cell precursors and follicular B cells. B cells in cDKO mice also failed to mount a specific antibody response to both T- dependent and T-independent antigens with reduced specific antibody titers, together with decreased antigen uptake by marginal zone B cells and transportation to the follicle. In paper IV we investigated the effect of the hyperactive mutated WASp, found in X-linked neutropenia patients, on murine B and T cells. XLN-WASp mutations induced increased polymerized actin in both T and B cells. We detected reduced spreading but normal chemotaxis toward specific chemokines by both cell types. We also observed reduced proliferation of B cells but not T cells and increased apoptosis of both cell types in vitro. The latter is probably due to increased genomic instability in B and T cells as observed by a FISH-telomere assay. Altogether, this study shows that Rho GTPases and their effector proteins are crucial for correct cell function and the cellular and humoral immune responses. Notably, the phenotypic severity can be increased by depletion of closely related intracellular proteins suggesting the existence of compensatory mechanisms and overlapping roles. The characterization of the Rho GTPases function may contribute to more precise interventions and therapeutic success

cFFR as an alternative to FFR: please do not contrast simplicity!

info:eu-repo/semantics/publishedVersio

Women in the mutual societies of Portugal from the end of the nineteenth century to the 1930s

This chapter aims to express recent research on the history of women’s work and activism by focusing on women in the mutual societies of Portugal from a gender perspective. The main objective is thus analysing women’s rights and the discrimination prevailing in mixed associations (including women and men as members). Another central purpose involves recognising women-only associations as a space for meeting and collaboration amongst working-class women and feminists that attained a voice in the mutualism movement in which their claims on welfare issues targeted both themselves and their children. Furthermore, we seek to demonstrate that only in women’s mutual associations did the ideals of democracy and equality, advocated by mutualism, become fulfilled for women. However, in fact, only a few women participated in the mutualism congresses during the First Republic, with some women gaining prominent places in the Assemblies but without any known public interventions according to the sources.info:eu-repo/semantics/acceptedVersio

Self interacting Brans Dicke cosmology and Quintessence

Recent cosmological observations reveal that we are living in a flat accelerated expanding universe. In this work we have investigated the nature of the potential compatible with the power law expansion of the universe in a self interacting Brans Dicke cosmology with a perfect fluid background and have analyzed whether this potential supports the accelerated expansion. It is found that positive power law potential is relevant in this scenario and can drive accelerated expansion for negative Brans Dicke coupling parameter $\omega$. The evolution of the density perturbation is also analyzed in this scenerio and is seen that the model allows growing modes for negative $\omega$.Comment: 8pages, 5 figures, PRD style, some changes are made, figures added, reference added. To be published in Int. J. Mod. Phys.

Role of physical activity in the prevention of falls and their consequences in the elderly

This work aims to provide an inventory of the risk factors and consequences of falling in the elderly, namely fractures, and to identify strategies to prevent falls and minimise their effects. Falls in elderly people are a major cause of injuries, leading to a general fear of falling, poorer quality of life and even death. The increase in life expectancy brought by developments in the medical and health sciences has not always brought enhanced quality of life.More elderly people live with reduced functional capacities resulting in a higher prevalence of falls and associated problems for themselves and for society. Risk factors for falling, commonly resulting from normal aging processes, have already been identified through multiple studies. Exercise may play an important role in fall prevention and their consequences. Although, effective strategies are usually multi-disciplinary and focus simultaneously on several risk factors. However, only large-scale prevention programmes can have significant effective social impact. To minimise occurrence and consequences of falls, policies to systematically implement prevention programmes should be established

MotionDesigner: Augmented artistic performances with kinect-based human body motion tracking

In the last two decades the use of technology in art projects has proliferated, as is the case of the interactive projections based on movement used in artistic performances and installations. However, the artists responsible for creating this work typically have to rely on computer experts to implement this type of interactive systems. The tool herein presented, MotionDesigner, intends to assist the design of these systems by providing artists with higher levels of autonomy and efficiency during the creative process, allowing them to specify the rules by which a human body interacts with both the audio and the visuals used in their interactive art work. The presented tool relies on an RGB-D camera to modulate the multimedia content according to the performer’s body motion. MotionDesigner is extensible so as to accommodate additions required by artists. The tool has been tested with dancers, choreographers, and architects. Results show that MotionDesigner is a valuable aid to artists, working as a catalyst of their creative process.info:eu-repo/semantics/acceptedVersio

Role of physical activity in the occurrence of falls and fall-related injuries in community-dwelling adults over 50 years old

Purpose: This study examined the effect of the type, level and amount of physical activity in falls and fall-related injuries. Method: Participants were 506 community-dwelling adults aged450 years (390 women: 67.7 6.8 years and 116 men: 69.6 6.6 years). Falls, fall-related injuries (slight and severe), and physical activity (type, level and energy expenditure) were evaluated by questionnaires. Confounders included co-morbidities, fear of falling, environmental hazards and physical fitness. Results: After adjustment for confounders, logistic analysis revealed that the likelihood of falling decreased by 2% for each 100 metabolic expenditure (MET-min/week) of total physical activity and increased by 5% for each 100 MET-min/week of vigorous-intensity physical activity; total physical activity 41125 MET-min/week and vigorous physical activity 5500 MET-min/week were identified as cut-off values discriminating non-fallers from fallers. Compared to the low physical activity level, increased physical activity levels diminished the likelihood of the occurrence of severe fall-related injuries by 76% (moderate) and 58% (high; p50.05) in fallers. Conclusions: Being active, especially sufficiently active, reduces fall-related injuries by decreasing falls and by safeguarding against severe injuries when falls occur. At least 1125 MET-min/week of total physical activity including 4500 MET-min/week of vigorous intensity seems to prevent falls and, therefore, fall-related injuries