268 research outputs found

    Near-infrared and X-ray obscuration to the nucleus of the Seyfert 2 galaxy NGC 3281

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    We present the results of a near-infrared and X-ray study of the Seyfert 2 galaxy NGC 3281. Emission from the Seyfert nucleus is detected in both regions of the electromagnetic spectrum, allowing us to infer both the equivalent line of sight hydrogen column density, N_H = 71.0(+11.3,-12.3)e26/m^2 and the extinction due to dust, A_V = 22+/-11 magnitudes (90% confidence intervals). We infer a ratio of N_H/A_V which is an order of magnitude larger than that determined along lines of sight in the Milky Way and discuss possible interpretations. We consider the most plausible explanation to be a dense cloud in the foreground of both the X-ray and infrared emitting regions which obscures the entire X-ray source but only a fraction of the much larger infrared source.Comment: 23 pages including 9 figure

    Effects of dry needling on gait and muscle tone in Parkinson''s disease: a randomized clinical trial

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    Background: Alterations in gait and muscular rigidity are common and disabling in persons with Parkinson''s disease (PD). Objective: The aim of this study was to determine whether a single dry needling (DN) session can promote changes in gait and muscle tone in the lower extremities as well as in the evolution of the disease in persons with PD. Methods: A randomized double-blind clinical trial was designed. Participants were randomly assigned to an intervention group (IG) that received a session of DN over the semitendinosus, medial gastrocnemius, soleus and rectus femoris muscles, or to a control group (CG) that received a session of sham DN in the same muscles. The effects of DN were assessed using the timed up and go test (TUG), 10 meter walk test (10MWT), 6 minute walk test (6MWT) and myotonometry before, immediately after, and 7 days after the intervention. Results: Thirty-three participants were analyzed aged 69.9 +/- 7.2 years (mean +/- SD; 39% female). There were no significant differences between the IG and CG for any outcomes. Significant differences were observed when comparing the Pre and Follow-up values in the IG for functional mobility of gait in the TUG (p = 0.049), gait speed in the 10MWT (p = 0.041) and muscle tone in the lower extremities by myotonometry (frequency (p = 0.027) and stiffness (p = 0.013)). By comparison, there were no significant within-group differences in the CG. Conclusion: A single session of DN had no measurable benefit compared to a single session of sham DN. Within-group changes in the IG suggested improvements in functional mobility of gait and gait speed, as well as changes in the muscle tone in the lower extremities of PD patients, which could be worthy of further exploration by future research

    The Infrared Nuclear Emission of Seyfert Galaxies on Parsec Scales: Testing the Clumpy Torus models

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    We present subarcsecond resolution mid-infrared (mid-IR) photometry in the wavelength range from 8 to 20 micron of eighteen Seyfert galaxies, reporting high spatial resolution nuclear fluxes for the entire sample. We construct spectral energy distributions (SEDs) that the AGN dominates adding near-IR measurements from the literature at similar angular resolution. The IR SEDs of intermediate-type Seyferts are flatter and present higher 10 to 18 micron ratios than those of Seyfert 2. We fit the individual SEDs with clumpy torus models using the in-house-developed BayesClumpy tool. The models reproduce the high spatial resolution measurements. Regardless of the Seyfert type, even with high spatial resolution data, near- to mid-IR SED fitting poorly constrains the radial extent of the torus. For the Seyfert 2, we find that edge-on geometries are more probable than face-on views, with a number of clouds along equatorial rays of N = 5-15. The 10 micron silicate feature is generally modeled in shallow absorption. For the intermediate-type Seyferts, N and the inclination angle of the torus are lower than those of the Seyfert 2 nuclei, with the silicate feature appearing in weak emission or absent. The columns of material responsible for the X-ray absorption are larger than those inferred from the model fits for most of the galaxies, which is consistent with X-ray absorbing gas being located within the dust sublimation radius whereas the mid-IR flux arises from an area farther from the accretion disc. The fits yield both the bolometric luminosity of the intrinsic AGN and the torus integrated luminosity, from which we derive the reprocessing efficiency of the torus. In the models, the outer radial extent of the torus scales with the AGN luminosity, and we find the tori to be confined to scales less than 5 pc.Comment: 26 pages, 8 figures, 9 tables. Accepted for publication in Ap

    Influence of Satisfaction, Expectations and Perception of Performance on University Dropout during the Pandemic

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    [Resumen] El abandono universitario es un área de investigación creciente debido a las diversas consecuencias negativas que puede acarrear. Se trata de un fenómeno complejo en el que intervienen múltiples variables, entre ellas factores emocionales-motivacionales. Algunas de estas variables, como la satisfacción con la educación superior y las expectativas de la titulación, son especialmente relevantes entre los estudiantes de primer curso, y más aún en un contexto de virtualidad forzada, como ha sido el caso de la crisis del COVID-19. El objetivo de este estudio es analizar la relación entre las variables emocionales-motivacionales y la intención de abandono entre un grupo de estudiantes, así como evaluar la percepción de su rendimiento académico durante la pandemia. La muestra del estudio estuvo formada por 513 estudiantes de primer y segundo curso de diferentes titulaciones de Ciencias Sociales y Ciencias de la Salud de dos universidades públicas españolas. Se utilizó un cuestionario ad hoc para medir la intención de abandono y su relación con una serie de variables. Se realizaron análisis descriptivos y modelización en árbol de decisión. Los resultados revelan que las variables predictoras más significativas para explicar la intención de abandono son la satisfacción con la elección de la titulación, las expectativas y el aprendizaje de conocimientos relevantes para su futuro profesional. También se encontró que la percepción de los estudiantes de que su rendimiento académico había disminuido durante el COVID-19 era uno de los predictores del abandono.[Abstract] University dropout is a growing area of research owing to the diverse negative consequences it can entail. It is a complex phenomenon involving multiple variables, including emotional-motivational factors. Some of these variables, such as satisfaction with higher education and expectations of the degree, are especially relevant among first-year students, and even more so in a context of forced virtualization, as has been the case during the COVID-19 crisis. The aim of this study is to analyse the relationship between emotional-motivational variables and dropout intention among a group of students, and to assess their perception of their academic performance during the pandemic. The sample for the study comprised 513 first- and second-year students from different Social Sciences and Health Sciences degrees at two Spanish public universities. An ad hoc questionnaire was used to measure dropout intention and its relationship with a series of variables. Descriptive analyses and decision tree modelling were performed. The results reveal that the most significant predictor variables to explain dropout intention are satisfaction with degree choice, expectations, and learning knowledge that is relevant to their professional future. Students’ perception that their academic performance had decreased during COVID-19 was also found to be one of the predictors of dropout

    Agenesia de cava inferior. Una causa infrecuente de trombosis venosa profunda. Análisis de casos en un hospital comarcal

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    We describe the data of 5 cases of anomaly/agenesis of the IVC in patients admitted to our hospital between 2002 and 2013. The relationship between this entity and thrombophilia is suggested, and the association with other congenital anomalies described as renal agenesis and cardiac abnormalities.Describimos los datos de 5 casos de anomalía/agenesia de VCI en pacientes ingresados en nuestro centro entre 2002 y 2013. Se sugiere la relación entre esta entidad y trombofilia, así como la asociación a otras anomalías congénitas descritas como la agenesia renal y alteraciones cardíacas

    La política agrícola de la CEE

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    The second flight of the SUNRISE balloon-borne solar observatory: overview of instrument updates, the flight, the data and first results

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    The SUNRISE balloon-borne solar observatory, consisting of a 1~m aperture telescope that provided a stabilized image to a UV filter imager and an imaging vector polarimeter, carried out its second science flight in June 2013. It provided observations of parts of active regions at high spatial resolution, including the first high-resolution images in the Mg~{\sc ii}~k line. The obtained data are of very high quality, with the best UV images reaching the diffraction limit of the telescope at 3000~\AA\ after Multi-Frame Blind Deconvolution reconstruction accounting for phase-diversity information. Here a brief update is given of the instruments and the data reduction techniques, which includes an inversion of the polarimetric data. Mainly those aspects that evolved compared with the first flight are described. A tabular overview of the observations is given. In addition, an example time series of a part of the emerging active region NOAA AR~11768 observed relatively close to disk centre is described and discussed in some detail. The observations cover the pores in the trailing polarity of the active region, as well as the polarity inversion line where flux emergence was ongoing and a small flare-like brightening occurred in the course of the time series. The pores are found to contain magnetic field strengths ranging up to 2500~G and, while large pores are clearly darker and cooler than the quiet Sun in all layers of the photosphere, the temperature and brightness of small pores approach or even exceed those of the quiet Sun in the upper photosphere.Comment: Accepted for publication in The Astrophysical Journa

    Low nadir CD4+ T-cell counts predict gut dysbiosis in HIV-1 infection

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    Human immunodeficiency virus (HIV)-1 infection causes severe gut and systemic immune damage, but its effects on the gut microbiome remain unclear. Previous shotgun metagenomic studies in HIV-negative subjects linked low-microbial gene counts (LGC) to gut dysbiosis in diseases featuring intestinal inflammation. Using a similar approach in 156 subjects with different HIV-1 phenotypes, we found a strong, independent, dose-effect association between nadir CD4+ T-cell counts and LGC. As in other diseases involving intestinal inflammation, the gut microbiomes of subjects with LGC were enriched in gram-negative Bacteroides, acetogenic bacteria and Proteobacteria, which are able to metabolize reactive oxygen and nitrogen species; and were depleted in oxygen-sensitive methanogenic archaea and sulfate-reducing bacteria. Interestingly, subjects with LGC also showed increased butyrate levels in direct fecal measurements, consistent with enrichment in Roseburia intestinalis despite reductions in other butyrate producers. The microbiomes of subjects with LGC were also enriched in bacterial virulence factors, as well as in genes associated with beta-lactam, lincosamide, tetracycline, and macrolide resistance. Thus, low nadir CD4+ T-cell counts, rather than HIV-1 serostatus per se, predict the presence of gut dysbiosis in HIV-1 infected subjects. Such dysbiosis does not display obvious HIV-specific features; instead, it shares many similarities with other diseases featuring gut inflammation

    Sharp boundaries of Dpp signalling trigger local cell death required for Drosophila leg morphogenesis

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    Article available at http://dx.doi.org/10.1038/ncb1518Morphogens are secreted signalling molecules that govern many developmental processes1. In the Drosophila wing disc, the transforming growth factor (TGF) homologue Decapentaplegic (Dpp) forms a smooth gradient and specifies cell fate by conferring a defined value of morphogen activity. Thus, neighbouring cells have similar amounts of Dpp protein, and if a sharp discontinuity in Dpp activity is generated between these cells, Jun kinase (JNK)-dependent apoptosis is triggered to restore graded positional information2, 3. To date, it has been assumed that this apoptotic process is only activated when normal signalling is distorted. However, we now show that a similar process occurs during normal development: rupture in Dpp activity occurs during normal segmentation of the distal legs of Drosophila. This sharp boundary of Dpp signalling, independently of the absolute level of Dpp activity, induces a JNK—reaper-dependent apoptosis required for the morphogenesis of a particular structure of the leg, the joint. Our results show that Dpp could induce a developmental programme not only in a concentration dependent manner, but also by the creation of a sharp boundary of Dpp activity. Furthermore, the same process could be used either to restore a normal pattern in response to artificial disturbance or to direct a morphogenetic process.This work has been supported by grants from the Dirección General de Investigación Científica y Técnica (BMC 2002-00300), the Comunidad Autónoma de Madrid (08.1/0031/2001.1 and GR/SAL/0147/2004) and an Institutional Grant from the Fundación Ramón Areces. C.M. is a recipient of a Formación del Personal Universitario (F.P.U.) fellowship from the Ministerio de Educación y Ciencia.Peer reviewe
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