Acoustic geometry for general relativistic barotropic irrotational fluid flow

"Acoustic spacetimes", in which techniques of differential geometry are used to investigate sound propagation in moving fluids, have attracted considerable attention over the last few decades. Most of the models currently considered in the literature are based on non-relativistic barotropic irrotational fluids, defined in a flat Newtonian background. The extension, first to special relativistic barotropic fluid flow, and then to general relativistic barotropic fluid flow in an arbitrary background, is less straightforward than it might at first appear. In this article we provide a pedagogical and simple derivation of the general relativistic "acoustic spacetime" in an arbitrary (d+1) dimensional curved-space background.Comment: V1: 23 pages, zero figures; V2: now 24 pages, some clarifications, 2 references added. This version accepted for publication in the New Journal of Physics. (Special issue on "Classical and Quantum Analogues for Gravitational Phenomena and Related Effects"

Captación de agua de niebla en determinados enclaves del sudeste de la Península Ibérica

Ponencia presentada en: IX Congreso de la Asociación Española de Climatología celebrado en Almería entre el 28 y el 30 de octubre de 2014.[ES]El sudeste de la Península Ibérica y, en concreto, las provincias de Alicante, Murcia y Almería, es un área especialmente sensible a la problemática de la escasez de agua, debido a su clima de escasas precipitaciones y de sus habituales periodos largos sin lluvias. Es por ello, que la búsqueda de fuentes de agua alternativas puede ayudar a mejorar este problema. En este trabajo, se hace un estudio sobre el potencial de captación de agua de niebla mediante métodos pasivos en siete emplazamientos de montaña, analizando a su vez sus principales características. La tasa de captación obtenida durante el periodo comprendido entre enero de 2010 y abril de 2011, ha variado entre 7.1 l/m2/d en Bernia y 0.8 l/m2/d en Helada. El episodio de recolección de niebla de mayor duración ha sido de 86 horas consecutivas, acumulándose un total 465 l/m2. El estudio nos ha permitido determinar la dirección óptima en la que se debería instalar un captador de niebla industrial de tipo pantalla así como llevar a cabo una estimación del volumen de agua potencial que se podría haber recolectado en cada emplazamiento.[EN]Little or no rain for an extended period of time is typical in the Southeast of the Iberian Peninsula and in particular, in the provinces of Alicante, Murcia and Almería. Therefore, scarcity of water is considered to be a problem in this area. Fog-water is being used successfully in many parts of the world as a new source of water. In this paper, we study the potential of fog-water harvesting and the main features of fog at seven mountain sites of this area. During the period between January 2010 and April 2011, fog collection rates varied from 7.1 l/m2/d at Bernia to 0.8 l/m2/d at Helada. The longest fog event lasted for 86 hours, accumulating 465 l/m2 of fog-water. The study allowed us to determine the optimal direction and the potential volume of fog-water for a flat fog collector at each site.Este proyecto ha sido financiado por el proyecto NIEVA «Evaluación del agua de niebla en la vertiente mediterránea de la Península Ibérica. Potenciales usos y aplicaciones», CGL2008- 04550/CLI, así como por el proyecto CGL2011-30433-C02-01 del M. Ciencia e Innovación

Classical and semi-classical energy conditions

The standard energy conditions of classical general relativity are (mostly) linear in the stress-energy tensor, and have clear physical interpretations in terms of geodesic focussing, but suffer the significant drawback that they are often violated by semi-classical quantum effects. In contrast, it is possible to develop non-standard energy conditions that are intrinsically non-linear in the stress-energy tensor, and which exhibit much better well-controlled behaviour when semi-classical quantum effects are introduced, at the cost of a less direct applicability to geodesic focussing. In this article we will first review the standard energy conditions and their various limitations. (Including the connection to the Hawking--Ellis type I, II, III, and IV classification of stress-energy tensors). We shall then turn to the averaged, nonlinear, and semi-classical energy conditions, and see how much can be done once semi-classical quantum effects are included.Comment: V1: 25 pages. Draft chapter, on which the related chapter of the book "Wormholes, Warp Drives and Energy Conditions" (to be published by Springer), will be based. V2: typos fixed. V3: small typo fixe

Has the Universe always expanded ?

We consider a cosmological setting for which the currently expanding era is preceded by a contracting phase, that is, we assume the Universe experienced at least one bounce. We show that scalar hydrodynamic perturbations lead to a singular behavior of the Bardeen potential and/or its derivatives (i.e. the curvature) for whatever Universe model for which the last bounce epoch can be smoothly and causally joined to the radiation dominated era. Such a Universe would be filled with non-linear perturbations long before nucleosynthesis, and would thus be incompatible with observations. We therefore conclude that no observable bounce could possibly have taken place in the early universe if Einstein gravity together with hydrodynamical fluids is to describe its evolution, and hence, under these conditions, that the Universe has always expanded.Comment: 11 pages, LaTeX-ReVTeX, no figures, submitted to PR

Primordial perturbations in a non singular bouncing universe model

We construct a simple non singular cosmological model in which the currently observed expansion phase was preceded by a contraction. This is achieved, in the framework of pure general relativity, by means of a radiation fluid and a free scalar field having negative energy. We calculate the power spectrum of the scalar perturbations that are produced in such a bouncing model and find that, under the assumption of initial vacuum state for the quantum field associated with the hydrodynamical perturbation, this leads to a spectral index n=-1. The matching conditions applying to this bouncing model are derived and shown to be different from those in the case of a sharp transition. We find that if our bounce transition can be smoothly connected to a slowly contracting phase, then the resulting power spectrum will be scale invariant.Comment: 11 pages, RevTeX 4, 8 figures, submitted to Phys. Rev.

Social mobility and healthy behaviours from a gender perspective in the Spanish multicase-control study (MCC-Spain)

There is evidence for the influence of socioeconomic status (SES) on healthy behaviours but the effect of social mobility (SM) is not yet well known. This study aims to analyse the influence of origin and destination SES (O-SES and D-SES) and SM on healthy behaviours and co-occurrence, from an integrated gender and age perspective. Data were obtained from the controls of MCC-Spain between 2008-2013 (3,606 participants). Healthy behaviours considered: healthy diet, moderate alcohol consumption, non-smoking and physical activity. SM was categorized as stable high, upward, stable medium, downward or stable low. Binary and multinomial logistic regression models were adjusted. Those aged <65, with a low O-SES, D-SES and stable low SM are less likely to have healthy behaviours in the case of both women (physically active: OR = 0.65 CI = 0.45-0.94, OR = 0.71 CI = 0.52-0.98, OR = 0.61 CI = 0.41-0.91) and men (non-smokers: OR = 0.44 CI = 0.26-0.76, OR = 0.54 CI = 0.35-0.83, OR = 0.41 CI 0.24-0.72; physically active: OR = 0.57 CI = 0.35-0.92, OR = 0.64 CI = 0.44-0.95, OR = 0.53 CI = 0.23-0.87). However, for those aged ≥65, this probability is higher in women with a low O-SES and D-SES (non-smoker: OR = 8.09 CI = 4.18-15.67, OR = 4.14 CI = 2.28-7.52; moderate alcohol consumption: OR = 3.00 CI = 1.45-6.24, OR = 2.83 CI = 1.49-5.37) and in men with a stable low SM (physically active: OR = 1.52 CI = 1.02-1.26). In the case of men, the same behaviour pattern is observed in those with a low O-SES as those with upward mobility, with a higher probability of co-occurring behaviours (three-to-four behaviours: OR = 2.00 CI = 1.22-3.29; OR = 3.13 CI = 1.31-7.48). The relationship of O-SES, D-SES and SM with healthy behaviours is complex and differs according to age and gender.This research was supported by the “Acción Transversal del Cancer”, approved by the Spanish Council of Ministers on 11th October 2007, by the Instituto de Salud Carlos III-FEDER [grant number:PI08/1770, PI08/0533, PI08/1359, PS09/00773-Cantabria, PS09/01286-León, PS09/01903-Valencia, PS09/02078-Huelva, PS09/ 01662-Granada, PI11/01403, PI11/01889-FEDER, PI11/00226, PI11/01810, PI11/02213, PI12/00488, PI12/00265, PI12/01270, PI12/00715, PI12/00150, PI14/01219, PI14/0613, PI15/00069, PI15/00914, PI15/01032, PI11/01810, PI14/01219, PI11/02213, PIE16/00049, PI17/01179, PI17-00092], by the Fundación Marqués de Valdecilla [grant number: API 10/09], by the ICGC International Cancer Genome Consortium CLL (The ICGC CLL-Genome Project is funded by Spanish Ministerio de Economía y Competitividad (MINECO) through the Instituto de Salud Carlos III (ISCIII)), by the Red Temática de Investigación del Cáncer (RTICC) del ISCIII [grant number: RD12/0036/0036], by the Junta de Castilla y León [grant number: LE22A10-2], by the Consejería de Salud of the Junta de Andalucía [grant number: PI-0571-2009, PI-0306-2011, salud201200057018tra], by the Conselleria de Sanitat of the Generalitat Valenciana [grant number: AP_061/10], by the Recercaixa [grant number: 2010ACUP00310], by the Regional Government of the Basque Country, by the Consejería de Sanidad de la Región de Murcia, by the European Commission [grant number: FOOD-CT-2006-036224-HIWATE], by the Spanish Association Against Cancer (AECC) Scientific Foundation [grant number: GCTRA18022MORE], by the Catalan Government-Agency for Management of University and Research Grants (AGAUR) [grant number: 2014SGR647, 2014SGR850 and 2017SGR723], by the Fundación Caja de Ahorros de Asturias and by the University of Oviedo. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.S

Effectiveness of thrombectomy in stroke according to baseline prognostic factors: inverse probability of treatment weighting analysis of a population-based registry

Background and Purpose In real-world practice, the benefit of mechanical thrombectomy (MT) is uncertain in stroke patients with very favorable or poor prognostic profiles at baseline. We studied the effectiveness of MT versus medical treatment stratifying by different baseline prognostic factors. Methods Retrospective analysis of 2,588 patients with an ischemic stroke due to large vessel occlusion nested in the population-based registry of stroke code activations in Catalonia from January 2017 to June 2019. The effect of MT on good functional outcome (modified Rankin Score ≤2) and survival at 3 months was studied using inverse probability of treatment weighting (IPTW) analysis in three pre-defined baseline prognostic groups: poor (if pre-stroke disability, age >85 years, National Institutes of Health Stroke Scale [NIHSS] >25, time from onset >6 hours, Alberta Stroke Program Early CT Score 3), good (if NIHSS <6 or distal occlusion, in the absence of poor prognostic factors), or reference (not meeting other groups’ criteria). Results Patients receiving MT (n=1,996, 77%) were younger, had less pre-stroke disability, and received systemic thrombolysis less frequently. These differences were balanced after the IPTW stratified by prognosis. MT was associated with good functional outcome in the reference (odds ratio [OR], 2.9; 95% confidence interval [CI], 2.0 to 4.4), and especially in the poor baseline prognostic stratum (OR, 3.9; 95% CI, 2.6 to 5.9), but not in the good prognostic stratum. MT was associated with survival only in the poor prognostic stratum (OR, 2.6; 95% CI, 2.0 to 3.3). Conclusions Despite their worse overall outcomes, the impact of thrombectomy over medical management was more substantial in patients with poorer baseline prognostic factors than patients with good prognostic factors

Effectiveness of an intervention for improving drug prescription in primary care patients with multimorbidity and polypharmacy:Study protocol of a cluster randomized clinical trial (Multi-PAP project)

This study was funded by the Fondo de Investigaciones Sanitarias ISCIII (Grant Numbers PI15/00276, PI15/00572, PI15/00996), REDISSEC (Project Numbers RD12/0001/0012, RD16/0001/0005), and the European Regional Development Fund ("A way to build Europe").Background: Multimorbidity is associated with negative effects both on people's health and on healthcare systems. A key problem linked to multimorbidity is polypharmacy, which in turn is associated with increased risk of partly preventable adverse effects, including mortality. The Ariadne principles describe a model of care based on a thorough assessment of diseases, treatments (and potential interactions), clinical status, context and preferences of patients with multimorbidity, with the aim of prioritizing and sharing realistic treatment goals that guide an individualized management. The aim of this study is to evaluate the effectiveness of a complex intervention that implements the Ariadne principles in a population of young-old patients with multimorbidity and polypharmacy. The intervention seeks to improve the appropriateness of prescribing in primary care (PC), as measured by the medication appropriateness index (MAI) score at 6 and 12months, as compared with usual care. Methods/Design: Design:pragmatic cluster randomized clinical trial. Unit of randomization: family physician (FP). Unit of analysis: patient. Scope: PC health centres in three autonomous communities: Aragon, Madrid, and Andalusia (Spain). Population: patients aged 65-74years with multimorbidity (≥3 chronic diseases) and polypharmacy (≥5 drugs prescribed in ≥3months). Sample size: n=400 (200 per study arm). Intervention: complex intervention based on the implementation of the Ariadne principles with two components: (1) FP training and (2) FP-patient interview. Outcomes: MAI score, health services use, quality of life (Euroqol 5D-5L), pharmacotherapy and adherence to treatment (Morisky-Green, Haynes-Sackett), and clinical and socio-demographic variables. Statistical analysis: primary outcome is the difference in MAI score between T0 and T1 and corresponding 95% confidence interval. Adjustment for confounding factors will be performed by multilevel analysis. All analyses will be carried out in accordance with the intention-to-treat principle. Discussion: It is essential to provide evidence concerning interventions on PC patients with polypharmacy and multimorbidity, conducted in the context of routine clinical practice, and involving young-old patients with significant potential for preventing negative health outcomes. Trial registration: Clinicaltrials.gov, NCT02866799Publisher PDFPeer reviewe

Morphogenic cell and protoplast cultures of tritordeum

Immature embryo- and anther-derived suspension and protoplast cultures were established in hexaploid tritordeum. The morphogenic capability of these cultures was studied under different nitrogen regimes. Both embryo- and anther-derived suspensions showed morphogenic capability. Suspension and protoplast cultures established from immature embryos gave rise to green shoots and green plants, whereas albino plants were regenerated when anther cultures were used as suspension-starting material. Chromosomal stability of suspensions and regenerated plants was analysed, revealing considerable instability in these cultures.Financial support by the Bundesministerium fur Förschung und Techno- logic (BMFT, Bonn; grant BEO 21/0316600A) is likewise acknowledged.Peer reviewe