388 research outputs found

    Understanding chemical evolution in resolved galaxies -- I The local star fraction-metallicity relation

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    This work studies the relation between gas-phase oxygen abundance and stellar-to-gas fraction in nearby galaxies. We first derive the theoretical prediction, and argue that this relation is fundamental, in the sense that it must be verified regardless of the details of the gas accretion and star formation histories. Moreover, it should hold on "local" scales, i.e. in regions of the order of 1 kpc. These predictions are then compared with a set of spectroscopic observations, including both integrated and resolved data. Although the results depend somewhat on the adopted metallicity calibration, observed galaxies are consistent with the predicted relation, imposing tight constraints on the mass-loading factor of (enriched) galactic winds. The proposed parametrization of the star fraction-metallicity relation is able to describe the observed dependence of the oxygen abundance on gas mass at fixed stellar mass. However, the "local" mass-metallicity relation also depends on the relation between stellar and gas surface densities.Comment: 10 pages, 4 figures. Matches accepted version (significant typo corrected

    Linking tourism, retirement migration and social capital

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    A general trend in the study of international retirement migration has been the increased attention paid to the social contacts and network connections of the migrants in both the destination and the origin areas. These studies have examined the extent to which migrants build social relationships with their neighbours and the host society while also maintaining social links with their countries of origin, addressing the central role that leisure travel plays in sustaining increasingly dispersed social networks and maintaining the social capital of these networks and of the individuals involved in them. Using a case study approach to examine British retirement migration to Spain, we explore the relevance of transnational social networks in the context of international retirement migration, particularly the intensity of bidirectional visiting friends and relatives (VFR) tourism flows and the migrants' social contacts with friends and/or family back in their home country. Building on the concept of social capital and Putnam's distinction between bonding and bridging social capital, we propose a framework for the analysis of the migrants' international social networks. The results of a study conducted based on a sample of 365 British retirees living in the coast of Alicante (Spain) show both the strength of the retirees' international bonding social capital and the role of 'VFR's travel and communication technologies in sustaining the migrants' transnational social practices and, ultimately, their international bonding social capital. It also provides evidence for the reinforcing links between tourism-related mobility and amenity-seeking migration in later life. © 2013 © 2013 Taylor & Francis

    Homogenization of the one-dimensional wave equation

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    We present a method for two-scale model derivation of the periodic homogenization of the one-dimensional wave equation in a bounded domain. It allows for analyzing the oscillations occurring on both microscopic and macroscopic scales. The novelty reported here is on the asymptotic behavior of high frequency waves and especially on the boundary conditions of the homogenized equation. Numerical simulations are reported

    PP2A is activated by cytochrome c upon formation of a diffuse encounter complex with SET/TAF-Iß

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    Intrinsic protein flexibility is of overwhelming relevance for intermolecular recognition and adaptability of highly dynamic ensemble of complexes, and the phenomenon is essential for the understanding of numerous biological processes. These conformational ensembles—encounter complexes—lack a unique organization, which prevents the determination of well-defined high resolution structures. This is the case for complexes involving the oncoprotein SET/template-activating factor-Iß (SET/TAF-Iß), a histone chaperone whose functions and interactions are significantly affected by its intrinsic structural plasticity. Besides its role in chromatin remodeling, SET/TAF-Iß is an inhibitor of protein phosphatase 2A (PP2A), which is a key phosphatase counteracting transcription and signaling events controlling the activity of DNA damage response (DDR) mediators. During DDR, SET/TAF-Iß is sequestered by cytochrome c (Cc) upon migration of the hemeprotein from mitochondria to the cell nucleus. Here, we report that the nuclear SET/TAF-Iß:Cc polyconformational ensemble is able to activate PP2A. In particular, the N-end folded, globular region of SET/TAF-Iß (a.k.a. SET/TAF-Iß ¿C)—which exhibits an unexpected, intrinsically highly dynamic behavior—is sufficient to be recognized by Cc in a diffuse encounter manner. Cc-mediated blocking of PP2A inhibition is deciphered using an integrated structural and computational approach, combining small-angle X-ray scattering, electron paramagnetic resonance, nuclear magnetic resonance, calorimetry and molecular dynamics simulations

    Triplet formation inhibits amplified spontaneous emission in perylene-based polycyclic aromatic hydrocarbons

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    Polycyclic Aromatic Hydrocarbons (PAHs) have demonstrated potential as active laser materials, showing good Amplified Stimulated Emission (ASE) properties. However, the molecular origin of their ASE properties is still unclear and depends on the particular compound. In this work we study the ASE properties of polystyrene films hosting three different perylene-based PAHs YZ-1, YZ-2 and YZ-3, where only YZ-3 has displayed ASE. Their molecular structure has been systematically changed to establish the connection between their molecular structure and their ASE properties. A complete spectroscopic study, with ground state and time-resolved techniques, show that, even at low yields, triplets play a critical role as a major loss mechanism. Their slow relaxation to ground state completely hinders the required unbalance of the S1 and S0 states for succesful ASE. Quantum chemical calculations suggest that a lower triplet density of states for YZ-3 is responsible for the blockage in triplet formation and, therefore, does not restrict ASE. This work not only presents a new PAH showing ASE, but also unequivocable proves the massive importance of triplet states in the development of organic lasers.JW acknowledges financial support from A*STAR AME grant (A20E5c0089). The group at the University of Alicante thanks financial support from the “Ministerio de Ciencia e Innovación” (MCIN) of Spain and the European Regional Development Fund (grant No. PID2020-119124RB-I00) and from the Generalitat Valenciana though grant No. AICO/2021/093. Besides, this study is part of the Advanced Materials program supported by the Spanish MCIN with funding from European Union Next Generation EU and by Generalitat Valenciana (grant no. MFA/2022/045). The group at the UA thanks Dr. J.M Villalvilla and Dr. J.A. Quintana for useful discussions. We also thank the Research Central Services (SCAI) of the University of Málaga for the access to the EVI, EEL and MENL to perform ground state and transient spectroscopic characterisation. JC thanks funding provided by MINECO/FEDER (PID2021-127127NB-I00, PID2019-110305GB-I00) and Junta de Andalucía (PROYEXCEL-0328)

    Fracture experience among participants from the FROCAT study: what thresholding is appropriate using the FRAX tool?

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    ObjectiveTo perform an external validation of FRAX algorithm thresholds for reporting level of risk of fracture in Spanish women (low <5%; intermediate ?5% and <7.5%; high ?7.5%) taken from a prospective cohort “FRIDEX”.MethodsA retrospective study of 1090 women aged ?40 and ?90 years old obtained from the general population (FROCAT cohort). FRAX was calculated with data registered in 2002. All fractures were validated in 2012. Sensitivity analysis was performed.ResultsWhen analyzing the cohort (884) excluding current or past anti osteoporotic medication (AOM), using our nominated thresholds, among the 621 (70.2%) women at low risk of fracture, 5.2% [CI95%: 3.4–7.6] sustained a fragility fracture; among the 99 at intermediate risk, 12.1% [6.4–20.2]; and among the 164 defined as high risk, 15.9% [10.6–24.2]. Sensitivity analysis against model risk stratification FRIDEX of FRAX Spain shows no significant difference. By including 206 women with AOM, the sensitivity analysis shows no difference in the group of intermediate and high risk and minimal differences in the low risk group.ConclusionsOur findings support and validate the use of FRIDEX thresholds of FRAX when discussing the risk of fracture and the initiation of therapy with patients

    Inside the metropolis: the articulation of Spanish metropolitan areas into local labor markets

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    In this article, we delimit local labor markets (LLMs) in order to analyze the internal structure and organization of Spanish metropolitan areas. LLMs are defined as self-contained and cohesive areas in terms of commuting flows. Unlike the conventional approach to polycentrism based on the analysis of commuting flows that begins with the identification of subcenters, our analytical strategy does assume any a priori structure and is compatible with the relationship between places of work and residence having other locational and spatial organization patterns. The analysis is performed at three different scales of detail linked to three self-containment levels for the LLMs delimited and three population groups (total, males, and females). The results show that metropolitan areas are complex, fuzzy, multidimensional spaces, where the conditions of spatial organization are manifested in different ways depending on the parameters and variables used.This work was supported by the Spanish Ministry of Economy and Competitiveness [grant numbers CSO2011-29943-C03-01, CSO2011-29943-C03-02, CSO2014-55780-C3-1-P, and CSO2014-55780-C3-2-P (National R&D&I Plan)]

    Proposing to use artificial neural Networks for NoSQL attack detection

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    [EN] Relationships databases have enjoyed a certain boom in software worlds until now. These days, with the rise of modern applications, unstructured data production, traditional databases do not completely meet the needs of all systems. Regarding these issues, NOSQL databases have been developed and are a good alternative. But security aspects stay behind. Injection attacks are the most serious class of web attacks that are not taken seriously in NoSQL. This paper presents a Neural Network model approach for NoSQL injection. This method attempts to use the best and most effective features to identify an injection. The features used are divided into two categories, the first one based on the content of the request, and the second one independent of the request meta parameters. In order to detect attack payloads features, we work on character level analysis to obtain malicious rate of user inputs. The results demonstrate that our model has detected more attack payloads compare with models that work black list approach in keyword level

    Carbon-bridged oligo(p-phenylenevinylene)s for photostable and broadly tunable, solution-processable thin film organic lasers

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    Thin film organic lasers represent a new generation of inexpensive, mechanically flexible devices for spectroscopy, optical communications and sensing. For this purpose, it is desired to develop highly efficient, stable, wavelength-tunable and solution-processable organic laser materials. Here we report that carbon-bridged oligo(p-phenylenevinylene)s serve as optimal materials combining all these properties simultaneously at the level required for applications by demonstrating amplified spontaneous emission and distributed feedback laser devices. A series of six compounds, with the repeating unit from 1 to 6, doped into polystyrene films undergo amplified spontaneous emission from 385 to 585 nm with remarkably low threshold and high net gain coefficients, as well as high photostability. The fabricated lasers show narrow linewidth (105 pump pulses for oligomers with three to six repeating units) and wavelength tunability across the visible spectrum (408–591 nm).The work in Spain was supported by the Spanish Government (MINECO) and the European Community (FEDER) through grant nos. MAT-2011–28167-C02-01 and CTQ2012-33733 and from the Junta de Andalucía through research project P09-FQM-4708. M.M.-V. has been partly supported by a MINECO FPI fellowship (no. BES-2009-020747). Dr Merino and Dr Retolaza, at Tekniker (Spain), are acknowledged for supplying the NIL fabricated resonators. We also thank I. Garcés for technical assistance. The work in Tokyo was supported by MEXT, Japan (for KAKENHI 15H05754 to E.N. and JST-PRESTO ‘New Materials Science and Element Strategy’ to H.T.)

    PARP-1 activation after oxidative insult promotes energy stress-dependent phosphorylation of YAP1 and reduces cell viability

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    [EN]Poly(ADP-ribose) polymerase 1 (PARP-1) is a nuclear enzyme that catalyze the transfer of ADP-ribose units from NAD+ to several target proteins involved in cellular stress responses. Using WRL68 (HeLa derivate) cells, we previously showed that PARP-1 activation induced by oxidative stress after H2O2 treatment lead to depletion of cellular NAD+ and ATP, which promoted cell death. In this work, LC-MS/MS-based phosphoproteomics in WRL68 cells showed that the oxidative damage induced by H2O2 increased the phosphorylation of YAP1, a transcriptional co-activator involved in cell survival, and modified the phosphorylation of other proteins involved in transcription. Genetic or pharmacological inhibition of PARP-1 in H2O2-treated cells reduced YAP1 phosphorylation and degradation and increased cell viability. YAP1 silencing abrogated the protective effect of PARP-1 inhibition, indicating that YAP1 is important for the survival of WRL68 cells exposed to oxidative damage. Supplementation of NAD+ also reduced YAP1 phosphorylation, suggesting that the loss of cellular NAD+ caused by PARP-1 activation after oxidative treatment is responsible for the phosphorylation of YAP1. Finally, PARP-1 silencing after oxidative treatment diminished the activation of the metabolic sensor AMPK. Since NAD+ supplementation reduced the phosphorylation of some AMPK substrates, we hypothesized that the loss of cellular NAD+ after PARP-1 activation may induce an energy stress that activates AMPK. In summary, we showed a new crucial role of PARP-1 in the response to oxidative stress in which PARP-1 activation reduced cell viability by promoting the phosphorylation and degradation of YAP1 through a mechanism that involves the depletion of NAD+
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