37 research outputs found

    On the entropy of a stealth vector-tensor black hole

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    We apply Wald's formalism to a Lagrangian within generalised Proca gravity that admits a Schwarzschild black hole with a non-trivial vector field. The resulting entropy differs from that of the same black hole in General Relativity by a logarithmic correction modulated by the only independent charge of the vector field. We find conditions on this charge to guarantee that the entropy is a non-decreasing function of the black hole area, as is the case in GR. If this requirement is extended to black hole mergers, we find that for Planck scale black holes, a non-decreasing entropy is possible only if the area of the final black hole is several times larger than the initial total area of the merger. Finally, we discuss some implications of the vector Galileon entropy from the point of view of entropic gravity

    Strong lensing by DHOST black holes

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    The deflection of light in the strong field limit is an important test for alternative theories of gravity. However, solutions for the metric that allow for analytic computations are not always available. We implement a hybrid analytic-numerical approximation to determine the deflection angle in static, spherically symmetric spacetimes. We apply this to a set of numerical black hole solutions within the class of theories known as Degenerate Higher Order Scalar-tensor Theories. Comparing our results to a more time consuming full numerical integration, we find that we can accurately describe the deflection angle for light rays passing at arbitrary distances from the photon sphere with a combination of two analytic-numerical approximations. Furthermore, we find a range of parameters where our DHOST black holes predict strong lensing effects whose size is comparable with the uncertainty in the properties of the supermassive black hole in M87 reported by the Event Horizon Telescope, showing that strong lensing is a viable alternative to put constraints on these models

    Cosmic acceleration in entropic cosmology

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    In this paper we study the viability of an entropic cosmological model. The effects of entropic gravity are derived from a modified entropy-area relationship with a volumetric entropy term. This model describes a late time limit cosmic acceleration, whose origin is related to a volumetric term in the entropy. Moreover, we analyze the phenomenological implications of the entropic model using the Supernovae Pantheon compilation and the observational Hubble parameter data to find consistency with cosmological observations. Finally, we show the equivalence between the entropic model and a brane world cosmological model, by means of an effective geometrical construction.Comment: 11 pages, 3 figures. Version accepted for Publication in Phys. Lett.

    Relación de la mejora de la calidad de vida de los sujetos que practican actividad física con daño cerebral adquirido

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    RELACIÓN DE LA MEJORA DE LA CALIDAD DE VIDA DE LOS SUJETOS QUE PRACTICAN ACTIVIDAD FÍSICA CON DEÑO CEREBRAL ADQUIRID

    Relación entre las pruebas de funcionalidad de la marcha en personas con daño cerebral adquirido en fase subaguda

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    Objetivo: Analizar el grado de relación entre cuatro pruebas que valoran la funcionalidad de la marcha en sujetos jóvenes con daño cerebral adquirido (DCA) en fase subaguda y conocer el grado de relación entre estas pruebas y la percepción subjetiva de seguridad en actividades de la vida diaria. Metodología: 67 participantes jóvenes con DCA en fase subaguda (43 hombres y 24 mujeres) con una edad media 35,09 años. Se realizó estadística descriptiva de todas las variables demográficas: género, edad, IMC, meses desde que se produjo la lesión y etiología lesional. Para analizar si existe correlación entre las variables se utilizó el coeficiente de Pearson. Resultados: El Timed 10-Meter Walk presenta una correlación muy alta con Timed Up and Go (TUG) (r=093), alta con el 6-Minute Walk Test (r=0,77) y moderada con el Step Test (r=0,56). El 6-Minute Walk Test presenta una correlación alta con el TUG (r=0,82) y una correlación moderada con el Step Test (r=0,69). El Step Test presenta una correlación moderada con el TUG (r= -0,68). The Activities-specific Balance Confidence Scale (ABC) presenta una correlación moderada con el Timed 10-Meter Walk (r=0,42), TUG (R=0,40), 6-Minute Walk Test (r=0,40) y Step Test (r=0,44). Conclusiones: Las pruebas de funcionalidad de la marcha presentan una correlación significativa entre moderada y muy alta en personas jóvenes con DCA. El ABC presenta una correlación significativa moderada con las cuatro variables de funcionalidad de la marcha analizadas en esta població

    The influence of syntactic knowledge on reading comprehension varies as a function of oral vocabulary in Spanish-speaking children

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    Background: Reading comprehension is a complex process influenced by many factors. However, the abilities that are known to influence reading comprehension may not contribute equally for children with different levels of oral language. Aims: Here we examined the relationship of two factors known to influence reading comprehension (morphology and syntax) in a group of children who varied in their levels of oral vocabulary. Method: Two hundred seventy-three typically developing Spanish-speaking fourth graders were assessed on non-verbal intelligence, word and pseudoword reading, oral vocabulary, morphological awareness and syntax, along with reading comprehension ability. Standardised oral language scores within this group ranged from the first to the 99th percentile. Mediated multiple regression with moderation was used to assess (1) whether the influence of oral vocabulary on reading comprehension was mediated by decoding, morphology or syntax and (2) whether the effects of syntax on reading comprehension varied as a function of oral vocabulary levels. Results: There was a direct positive relationship between vocabulary and reading comprehension, and this was mediated by word reading and syntax, but not by pseudoword reading or morphology. Furthermore, the relation between syntax and reading comprehension was moderated by oral vocabulary such that the strength of this relationship diminished as oral vocabulary levels increased. Conclusions: These findings suggest that longitudinal research is necessary to explore the possibility that a syntax intervention might be beneficial for readers with low oral vocabulary.FEDER 2014-2020Consejería de Economía, Conocimiento, Empresas y Universidad US-126479

    The effects of morphological and syntactic knowledge on reading comprehension in Spanish speaking children

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    Reading comprehension is a complex task requiring many underlying skills. Syntactic awareness and morphological awareness are two such skills that have been shown to be related to reading comprehension. However, the majority of studies have been carried out in English, and very few have explored these skills in monolingual Spanish speaking children. Here we explored to what extent syntactic awareness and morphological awareness contributed to text comprehension in Spanish. 501 typically developing Spanish speaking 4th graders were assessed on non-verbal intelligence, word and nonword reading, oral vocabulary, morphological and syntactic knowledge, along with reading comprehension ability. After excluding children with poor decoding or low non-verbal intelligence, 234 children were retained for analysis. Multiple linear regression modelling was used to assess the unique contribution of each variable to reading comprehension. As per findings reported in English, syntactic knowledge was a significant predictor of comprehension after controlling for age, gender, non-verbal IQ, word reading and oral vocabulary, as well as morphological knowledge. In contrast, and contrary to results normally reported for English speaking children, morphological knowledge did not explain any variance in reading comprehension beyond that explained by the control variables. These results highlight the important contribution of syntactic knowledge to text comprehension in Spanish speaking children, as well as the importance of undertaking research in languages other than English.Ministerio de Economía y Competitividad PSI2015-65656-

    S100A8/A9 Proteins Mediate Neutrophilic Inflammation and Lung Pathology during Tuberculosis

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    Rationale: A hallmark of pulmonary tuberculosis (TB) is the formation of granulomas. However, the immune factors that drive the formation of a protective granuloma during latent TB, and the factors that drive the formation of inflammatory granulomas during active TB, are not well defined. Objectives: The objective of this study was to identify the underlying immune mechanisms involved in formation of inflammatory granulomas seen during active TB. Methods: The immune mediators involved in inflammatory granuloma formation during TB were assessed using human samples and experimental models of Mycobacterium tuberculosis infection, using molecular and immunologic techniques. Measurements and Main Results: We demonstrate that in human patients with active TB and in nonhuman primate models of M. tuberculosis infection, neutrophils producing S100 proteins are dominant within the inflammatory lung granulomas seen during active TB. Using the mouse model of TB, we demonstrate that the exacerbated lung inflammation seen as a result of neutrophilic accumulation is dependent on S100A8/A9 proteins. S100A8/A9 proteins promote neutrophil accumulation by inducing production of proinflammatory chemokines and cytokines, and influencing leukocyte trafficking. Importantly, serum levels of S100A8/A9 proteins along with neutrophil-associated chemokines, such as keratinocyte chemoattractant, can be used as potential surrogate biomarkers to assess lung inflammation and disease severity in human TB. Conclusions: Our results thus show a major pathologic role for S100A8/A9 proteins in mediating neutrophil accumulation and inflammation associated with TB. Thus, targeting specific molecules, such as S100A8/A9 proteins, has the potential to decrease lung tissue damage without impacting protective immunity against TB

    Patient-reported-outcomes in subjects with painful lumbar or cervical radiculopathy treated with pregabalin: evidence from medical practice in primary care settings

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    The objective of this study was to evaluate the effect of pregabalin in painful cervical or lumbosacral radiculopathy treated in Primary Care settings under routine clinical practice. An observational, prospective 12-week secondary analysis was carried-out. Male and female above 18 years, naïve to PGB, with refractory chronic pain secondary to cervical/lumbosacral radiculopathy were enrolled. SF-MPQ, Sheehan Disability Inventory, MOS Sleep Scale, Hospital Anxiety and Depression Scale and the EQ-5D were administered. A total of 490 (34%) patients were prescribed PGB-monotherapy, 702 (48%) received PGB add-on, and 159 (11%) were administered non-PGB drugs. After 12 weeks, significant improvements in pain, associated symptoms of anxiety, depression and sleep disturbances, general health; and level of disability were observed in the three groups, being significantly greater in PGB groups. In routine medical practice, monotherapy or add-on pregabalin is associated with substantial pain alleviation and associated symptoms improvements in painful cervical or lumbosacral radiculopathy

    Search for Multimessenger Sources of Gravitational Waves and High-energy Neutrinos with Advanced LIGO during Its First Observing Run, ANTARES, and IceCube

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    Astrophysical sources of gravitational waves, such as binary neutron star and black hole mergers or core-collapse supernovae, can drive relativistic outflows, giving rise to non-thermal high-energy emission. High-energy neutrinos are signatures of such outflows. The detection of gravitational waves and high-energy neutrinos from common sources could help establish the connection between the dynamics of the progenitor and the properties of the outflow. We searched for associated emission of gravitational waves and high-energy neutrinos from astrophysical transients with minimal assumptions using data from Advanced LIGO from its first observing run O1, and data from the Antares and IceCube neutrino observatories from the same time period. We focused on candidate events whose astrophysical origins could not be determined from a single messenger. We found no significant coincident candidate, which we used to constrain the rate density of astrophysical sources dependent on their gravitational-wave and neutrino emission processes
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