The globular cluster NGC 2419: a crucible for theories of gravity

We present the analysis of a kinematic data set of stars in the globular cluster NGC 2419, taken with Keck/DEIMOS. Combined with a reanalysis of deep HST and Subaru imaging data, which provide an accurate luminosity profile of the cluster, we investigate the validity of a large set of dynamical models of the system, which are checked for stability via N-body simulations. We find that isotropic models in either Newtonian or Modified Newtonian Dynamics (MOND) are ruled out with extremely high confidence. However, a simple Michie model in Newtonian gravity with anisotropic velocity dispersion provides an excellent representation of the luminosity profile and kinematics. In contrast, with MOND we find that Michie models that reproduce the luminosity profile either over-predict the velocity dispersion on the outskirts of the cluster if the mass to light ratio is kept at astrophysically-motivated values, or else they under-predict the central velocity dispersion if the mass to light ratio is taken to be very small. We find that the best Michie model in MOND is a factor of 10000 less likely than the Newtonian model that best fits the system. A likelihood ratio of 350 is found when we investigate more general models by solving the Jeans equation with a Markov-Chain Monte Carlo scheme. We verified with N-body simulations that these results are not significantly different when the MOND external field effect is accounted for. If the assumptions that the cluster is in dynamical equilibrium, spherical, not on a peculiar orbit, and possesses a single dynamical tracer population of constant M/L are correct, we conclude that the present observations provide a very severe challenge for MOND. [abridged]Comment: 25 pages, 19 figures, accepted for publication in Ap

The Luminosity Function and stellar Mass to Light ratio of the massive globular cluster NGC2419

We used archival Hubble Space Telescope WFC3 images to obtain the Luminosity Function of the remote globular cluster NGC2419 from two magnitudes above the Horizontal Branch level down to \sim3.0 magnitudes below the Turn Off point (to M_I\sim6.4), approximately covering the range of initial stellar masses 0.5 M_sun<= m <= 0.9 M_sun. The completeness-corrected Luminosity Function does not display any change of shape over the radial range covered by the WFC3 data, out to ~6 core radii (r_c), or, equivalently, to ~2 half-light radii. The Luminosity Function in this radial range is also identical to that obtained from ground based data at much larger distances from the cluster centre (12r_c<= R<= 22r_c), in the magnitude range in which the two distributions overlap (M_I<= 4.0). These results support the conclusion by Dalessandro et al. that there is no significant mass segregation among cluster stars, hence the stellar mass-to-light ratio remains constant with distance from the cluster centre. We fitted the observed Luminosity Function with theoretical counterparts with the proper age and metallicity from different sets of stellar evolution models and we consistently derive a total V band mass-to-light ratio 1.2<= M/L_V<= 1.7, by extrapolating to the Hydrogen burning limit, with a best-fit value M/L_V=1.5 +/- 0.1. On the other hand, assuming that there are no cluster stars with m 0.8. These estimates provide useful constraints for dynamical models of the cluster that were forced to consider the stellar mass-to-light ratio as a (nearly) free parameter.Comment: Accepted for publication by MNRAS. Pdftex, 13 pages, 9 figure

Formation and evolution of compact binaries in globular clusters: II. Binaries with neutron stars

In this paper, the second of a series, we study the stellar dynamical and evolutionary processes leading to the formation of compact binaries containing neutron stars (NSs) in dense globular clusters (GCs). For this study, 70 dense clusters were simulated independently, with a total stellar mass ~2x10^7Msun, exceeding the total mass of all dense GCs in our Galaxy. We find that, in order to reproduce the empirically derived formation rate of low-mass X-ray binaries (LMXBs), we must assume that NSs can be formed via electron-capture supernovae (ECS) with typical natal kicks smaller than in core-collapse supernovae. Our results explain the observed dependence of the number of LMXBs on ``collision number'' as well as the large scatter observed between different GCs. We predict that the number of quiescent LMXBs in different GCs should not have a strong metallicity dependence. In our cluster model the following mass-gaining events create populations of MSPs that do not match the observations: (i) accretion during a common envelope event with a NS formed through ECS, and (ii) mass transfer (MT) from a WD donor. Some processes lead only to a mild recycling. In addition, for MSPs, we distinguish low-magnetic-field (long-lived) and high-magnetic-field (short-lived) populations. With this distinction and by considering only those mass-gaining events that appear to lead to NS recycling, we obtain good agreement of our models with the numbers and characteristics of observed MSPs in 47 Tuc and Terzan 5, as well as with the cumulative statistics for MSPs detected in GCs of different dynamical properties. We find that significant production of merging double NSs potentially detectable as short gamma-ray bursts occurs only in very dense, most likely core-collapsed GCs. (abridged)Comment: 25 pages, 7 figures, 12 tables, MNRAS accepte

Expression of proteins in Escherichia coli as fusions with maltose-binding protein to rescue non-expressed targets in a high-throughput protein-expression and purification pipeline

The rescue of protein-expression levels by cloning genes into MBP-fusion vector is described

(In)dependência funcional na dependente relação de homens tetraplégicos com seus (in)substituíveis pais/cuidadores

Objetivou-se identificar elementos da classificação internacional de funcionalidade, incapacidade e saúde, aplicáveis ao cuidado domiciliar de homens adultos tetraplégicos, com vistas à redução da dependência de ajuda de seus pais para as atividades da vida diária, e o autocuidado. Os dados foram coletados de junho de 2004 a março de 2005, a partir de entrevista semi-estruturada, realizada com 8 adultos acometidos de lesão medular alta, e com experiência de usuários do cuidado domiciliar. Optou-se pela análise de conteúdo, a partir das categorias de significados pautadas nos seguintes resultados: suporte familiar: segurança para as funções corporais do incapacitado; tecnologia assistiva: inventividades para promoção da qualidade do cuidado; medos, futuro incerto e perda dos pais: limiares e fragilidades humanas; e ganhos funcionais: respostas objetivas das funções corporais. Conclui-se que o apoio da família e, em especial, a presença dos pais, são fundamentais para enfrentar as limitações e reagir na busca de equilíbrio na deficiência, incapacidade, desvantagem e saúde dessa clientela, preparando-a para o alcance de gradativos ganhos funcionais e independência para atividades cotidianas e autocuidado.El estudio tuvo como objetivo identificar elementos de la clasificación internacional de funcionalidad, incapacidad y salud, aplicables al cuidado domiciliario de hombres adultos cuadripléjicos, con el fin de reducir la dependencia de la ayuda de sus padres en las actividades de la vida diaria y el autocuidado. Los datos fueron reunidos entre junio de 2004 y marzo de 2005, sobre la base de una entrevista semiestructurada efectuada a 8 adultos que sufrían de lesión medular alta y que recibían normalmente cuidado domiciliario. Se optó por el sistema de análisis de contenidos a partir de las categorías de significados pautados en los siguientes resultados: apoyo familiar: seguridad para las funciones corporales del discapacitado; tecnología de apoyo: soporte tecnológico para optimizar la calidad de los cuidados; miedos; futuro incierto y pérdida de los padres: los umbrales y las fragilidades humanas; y ganancias funcionales: respuestas objetivas de las funciones corporales. Se concluyó en que el apoyo familiar y, en particular, la presencia de los padres, son fundamentales para enfrentar las limitaciones y reaccionar en la búsqueda de equilibrios en la deficiencia, incapacidad, desventajas y salud de tales pacientes, preparándolos para alcanzar en forma gradual mejoras funcionales e independencia para realizar actividades diarias y ocuparse del autocuidado.The objective of this study was to identify elements of the international classification of functioning, disability and health, applicable to quadriplegic men's home care, to reduce the dependence on their parents' help for activities of daily living and self-care. Data were collected from June 2004 to March 2005. Semi-structured interviews were performed with eight adults with high spinal cord lesions who were being cared for at home . Content analysis was performed based on the categories of meaning extrapolated and the following themes were discovered : family support: safety for the corporal functions of the disabled; supporting technology: inventiveness to promote quality care; fears, uncertain future and parents' loss: thresholds and human fragilities; and functional gains: objective response of body functions. In conclusion, family support, and especially the presence of parents, is fundamental to facing limitations and to reacting in the search for balance with the deficiency, disability, disadvantage and health of that population, preparing them to achieve gradual functional gain and independence for daily activities and self-care

News from the Galactic suburbia: the chemical composition of the remote globular cluster NGC 2419

We present the chemical analysis of 49 giant stars of the globular cluster NGC 2419, using medium resolution spectra collected with the multi-object spectrograph DEIMOS@Keck. Previous analysis of this cluster revealed a large dispersion in the line strength of the infrared Ca II triplet, suggesting an intrinsic star-to-star scatter in its Fe or Ca content. From our analysis, we assess that all the investigated stars share the same [Fe/H], [Ca/Fe] and [Ti/Fe] abundance ratios, while a large spread in Mg and K abundances is detected. The distribution of [Mg/Fe] is bimodal, with ~40% of the observed targets having subsolar [Mg/Fe], down to [Mg/Fe] ~ -1 dex, a level of Mg-deficiency never observed before in globular clusters. It is found that the large dispersion in Mg abundances is likely the main origin of the observed dispersion of the Ca II triplet lines strengths (that can be erroneously interpreted in terms of Fe or Ca abundance scatter) because Mg plays a relevant role in the atmosphere of giant stars as an electron donor. A strong depletion in the Mg abundance leads to an increase of the line strength of the Ca II triplet, due to the variation in the electronic pressure, at a constant Fe and Ca abundance. Finally, we detect an anti-correlation between Mg and K abundances, not easily explainable within the framework of the current nucleosynthesis models.Comment: Accepted for publication in MNRAS (14 pages, 10 figures, 1 table

A review of air pollution impact on subjective well-being: Survey versus visual psychophysics

Air pollution is a worldwide environmental and health issue, especially in major developing countries. A recent World Health Organization report shows about 3 million deaths in the world in 2012 are due to ambient air pollution and China and India are the countries with the most severe challenge. Air pollution influences people's thought and experience of their lives directly by visual perceptions. This reduces people's subjective well-being (SWB) to a significant degree. Empirical researchers have made efforts to examine how self-reported well-being varies with air quality typically by survey method - matching SWB data with monitored air pollution data. Their findings show NO2, particles, lead, SO2 and O3 have significant negative impact on SWB. However, it is very hard to match air pollution characteristics from monitor stations with each respondent's state of SWB at the moment a survey is conducted. Also it is very hard to find the detailed trend impact from only air pollution factor on SWB. This review illustrates the features and limitations of previous survey studies on quantifying the effects of air pollution on subjective well-being. This review further displays the progress of psychophysics and its application in landscape and air quality research. We propose using psychophysics application to quantify air pollution impact on SWB

The role of multi-slice computed tomography in stable angina management: a current perspective

Contrast-enhanced CT coronary angiography (CTCA) has evolved as a reliable alternative imaging modality technique and may be the preferred initial diagnostic test in patients with stable angina with intermediate pre-test probability of CAD. However, because CTCA is moderately predictive for indicating the functional significance of a lesion, the combination of anatomic and functional imaging will become increasingly important. The technology will continue to improve with better spatial and temporal resolution at low radiation exposure, and CTCA may eventually replace invasive coronary angiography. The establishment of the precise role of CTCA in the diagnosis and management of patients with stable angina requires high-quality randomised study designs with clinical outcomes as a primary outcome

Proteomics of tissue factor silencing in cardiomyocytic cells reveals a new role for this coagulation factor in splicing machinery control

YesIt has long been known that Tissue Factor (TF) plays a role in blood coagulation and has a direct thrombotic action that is closely related to cardiovascular risk, but it is becoming increasingly clear that it has a much wider range of biological functions that range from inflammation to immunity. It is also involved in maintaining heart haemostasis and structure, and the observation that it is down-regulated in the myocardium of patients with dilated cardiomyopathy suggests that it influences cell-to-cell contact stability and contractility, and thus contributes to cardiac dysfunction. However, the molecular mechanisms underlying these coagulation-independent functions have not yet been fully elucidated. In order to analyse the influence of TF on the cardiomyocitic proteome, we used functional biochemical approaches incorporating label-free quantitative proteomics and gene silencing, and found that this provided a powerful means of identifying a new role for TF in regulating splicing machinery together with the expression of several proteins of the spliceosome, and mRNA metabolism with a considerable impact on cell viability

Predictors of functional outcome vary by the hemisphere of involvement in major ischemic stroke treated with intra-arterial therapy: a retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>Conflicting data exists regarding the effect of hemispheric lateralization on acute ischemic stroke outcome. Some of this variability may be related to heterogeneous study populations, particularly with respect to the level of arterial occlusion. Furthermore, little is known about the relationship between stroke lateralization and predictors of outcome. The purpose of this study was to characterize the impact of stroke lateralization on both functional outcome and its predictors in a well-defined population of anterior circulation proximal artery occlusions treated with IAT.</p> <p>Methods</p> <p>Thirty-five consecutive left- and 35 consecutive right-sided stroke patients with intracranial ICA and/or MCA occlusions who underwent IAT were retrospectively analyzed. Ischemic change on pre-treatment imaging was quantified. Reperfusion success was graded using the Mori scale. Good outcome at three months was defined as an mRS ≤ 2. Left- and right-sided strokes were compared for outcome and its predictors.</p> <p>Result</p> <p>Of 70 patients with median NIHSS score of 18 (IQR, 14-21), 19 (27.1%) had a good outcome. There were 21 terminal ICA and 49 MCA occlusions. There was no difference in the rate of good outcomes between left- (n = 9) and right-sided (n = 10) strokes (p = 0.99). There were no significant differences in occlusion level, age, ischemic change on initial imaging and degree of reperfusion between left- and right-sided strokes. Left-sided strokes had higher baseline NIHSS scores (p = 0.02) and lower admission SBP (p = 0.009). Independent predictors of outcome for left-sided strokes were NIHSS (p = 0.0002) and reperfusion (p = 0.006), and for right-sided strokes were age (p = 0.002) and reperfusion (p = 0.003). In univariate analysis, pre-treatment ischemic change on NCCT was associated with outcome only for left-sided strokes (p = 0.05).</p> <p>Conclusions</p> <p>In anterior circulation proximal artery occlusions treated with IAT, hemispheric lateralization influences the clinical and imaging predictors of outcome. Most notably, NIHSS predicts outcome only for the left-sided strokes in this population. This finding has important implications for outcome prediction in the acute setting and indicates a need for stroke severity scales more sensitive to right hemispheric deficits.</p