On the Influence of Magnetic Fields on the Structure of Protostellar Jets

We here present the first results of fully three-dimensional (3-D) MHD simulations of radiative cooling pulsed (time-variable) jets for a set of parameters which are suitable for protostellar outflows. Considering different initial magnetic field topologies in approximate $equipartition$ with the thermal gas, i.e., (i) a longitudinal, and (ii) a helical field, both of which permeating the jet and the ambient medium; and (iii) a purely toroidal field permeating only the jet, we find that the overall morphology of the pulsed jet is not very much affected by the presence of the different magnetic field geometries in comparison to a nonmagnetic calculation. Instead, the magnetic fields tend to affect essentially the detailed structure and emission properties behind the shocks at the head and at the pulse-induced internal knots, particularly for the helical and toroidal geometries. In these cases, we find, for example, that the $H_\alpha$ emissivity behind the internal knots can be about three to four times larger than that of the purely hydrodynamical jet. We also find that some features, like the nose cones that often develop at the jet head in 2-D calculations involving toroidal magnetic fields, are smoothed out or absent in the 3-D calculations.Comment: 13 pages, 3 figures, Accepted by ApJ Letters after minor corrections (for high resolution figures, see http://www.iagusp.usp.br/~adriano/h.tar

Time, institutional support and quality of decision making in child protection:A cross-country analysis

This paper examines perceptions of time and institutional support for decision making and staff confidence in child welfare staffs ultimate decisions – examining differences and similarities between and within the service-oriented Nordic countries (Norway and Finland) and the risk-oriented Anglo-American countries (England and California). The study identifies a high degree of work pressure across all the countries, lines of predominantly vertical institutional support and relatively high confidence in decisions. Finland stands out with higher perceived work pressure and with a horizontal support line, whereas England stands out with workers having a lower degree of confidence in their own and others’ decisions

Strong-field tidal distortions of rotating black holes: Formalism and results for circular, equatorial orbits

Tidal coupling between members of a compact binary system can have an interesting and important influence on that binary's dynamical inspiral. Tidal coupling also distorts the binary's members, changing them (at lowest order) from spheres to ellipsoids. At least in the limit of fluid bodies and Newtonian gravity, there are simple connections between the geometry of the distorted ellipsoid and the impact of tides on the orbit's evolution. In this paper, we develop tools for investigating tidal distortions of rapidly rotating black holes using techniques that are good for strong-field, fast-motion binary orbits. We use black hole perturbation theory, so our results assume extreme mass ratios. We develop tools to compute the distortion to a black hole's curvature for any spin parameter, and for tidal fields arising from any bound orbit, in the frequency domain. We also develop tools to visualize the horizon's distortion for black hole spin $a/M \le \sqrt{3}/2$ (leaving the more complicated $a/M > \sqrt{3}/2$ case to a future analysis). We then study how a Kerr black hole's event horizon is distorted by a small body in a circular, equatorial orbit. We find that the connection between the geometry of tidal distortion and the orbit's evolution is not as simple as in the Newtonian limit.Comment: 37 pages, 8 figures. Accepted for publication to Physical Review D. This version corrects a number of typographical errors found when reviewing the page proof

On connaît la chanson : la contrafacture des mélodies des trouvères dans le Ludus super Anticlaudianum d’Adam de la Bassée

The study of contrafacture – the setting of new words to an old melody -reveals a great deal about the culture in which medieval poets and composers lived and worked. The associations created in the minds of an initiated listening public could aid a composer in augmenting the central message of his work. However, the study of contrafacture proves valuable also for the ways in which it takes us beyond the simple one-way kind of influences at which critics all too often stop. The present article studies three contrafacta from Adam de la Bassée’s Ludus super Anticlaudianum in order to reveal suggestive evidence about the creation and reception of the Ludus and how the study of contrafacture has important implications in regard to trouvère lyric in general.L’étude de la contrafacture -la technique qui consiste à adapter une mélodie connue à de nouvelles paroles -révèle beaucoup sur le milieu culturel dans lequel les poètes et les compositeurs médiévaux vivaient et travaillaient. Les associations créées dans l’esprit d’un public initié lors de la performance des contrafactures pouvaient renforcer le message central d’un ouvrage. De plus, l’étude de la contrafacture nous aide à voir au-delà des processus d’influences simples auxquels la critique moderne tend à aboutir. Le présent article étudie trois contrafacta tirés du Ludus super Anticlaudiaum d’Adam de la Bassée afin d’émettre des hypothèses sur les conséquences de la création et de la réception du Ludus et de démontrer comment l’étude de la contrafacture mène à des implications importantes quant à notre compréhension de l’art des trouvères

On connaît la chanson : la contrafacture des mélodies des trouvères dans le Ludus super Anticlaudianum d’Adam de la Bassée

The study of contrafacture – the setting of new words to an old melody -reveals a great deal about the culture in which medieval poets and composers lived and worked. The associations created in the minds of an initiated listening public could aid a composer in augmenting the central message of his work. However, the study of contrafacture proves valuable also for the ways in which it takes us beyond the simple one-way kind of influences at which critics all too often stop. The present article studies three contrafacta from Adam de la Bassée’s Ludus super Anticlaudianum in order to reveal suggestive evidence about the creation and reception of the Ludus and how the study of contrafacture has important implications in regard to trouvère lyric in general.L’étude de la contrafacture -la technique qui consiste à adapter une mélodie connue à de nouvelles paroles -révèle beaucoup sur le milieu culturel dans lequel les poètes et les compositeurs médiévaux vivaient et travaillaient. Les associations créées dans l’esprit d’un public initié lors de la performance des contrafactures pouvaient renforcer le message central d’un ouvrage. De plus, l’étude de la contrafacture nous aide à voir au-delà des processus d’influences simples auxquels la critique moderne tend à aboutir. Le présent article étudie trois contrafacta tirés du Ludus super Anticlaudiaum d’Adam de la Bassée afin d’émettre des hypothèses sur les conséquences de la création et de la réception du Ludus et de démontrer comment l’étude de la contrafacture mène à des implications importantes quant à notre compréhension de l’art des trouvères

A meta-analysis of remote ischaemic conditioning in experimental stroke

Remote ischaemic conditioning (RIC) is achieved by repeated transient ischaemia of a distant organ/limb and is neuroprotective in experimental ischaemic stroke. However, the optimal time and methods of administration are unclear. Systematic review identified relevant preclinical studies; two authors independently extracted data on infarct volume, neurological deficit, RIC method (administration time, site, cycle number, length of limb occlusion (dose)), species and quality. Data were analysed using random effects models; results expressed as standardised mean difference (SMD). In 57 publications incorporating 99 experiments (1406 rats, 101 mice, 14 monkeys), RIC reduced lesion volume in transient (SMD −2.0; 95% CI −2.38, −1.61; p

Cavities and shocks in the galaxy group HCG 62 as revealed by Chandra, XMM and GMRT data

We report on the results of an analysis of Chandra, XMM-Newton and new GMRT data of the X-ray bright compact group of galaxies HCG 62, which is one of the few groups known to possess clear, small X-ray cavities in the inner regions. This is part of an ongoing X-ray/low-frequency radio study of 18 groups, initially chosen for the availability of good-quality X-ray data and evidence for AGN/hot gas interaction. At higher frequency (1.4 GHz), the HCG 62 cavity system shows minimal if any radio emission, but the new GMRT observations at 235 MHz and 610 MHz clearly detect extended low-frequency emission from radio lobes corresponding to the cavities. By means of the synergy of X-ray and low-frequency radio observations, we compare and discuss the morphology, luminosity and pressure of the gas and of the radio source. We find that the radio source is radiatively inefficient, with a ratio of radio luminosity to mechanical cavity power of $\sim 10^{-4}$, and that the radio pressure of the lobes is about one order of magnitude lower than the X-ray pressure of the surrounding thermal gas. Thanks to the high spatial resolution of the Chandra surface brightness and temperature profiles, we also identify a shock front located at 36 kpc to the south-west of the group center, close to the southern radio lobe, with a Mach number $\sim 1.5$ and a total power which is about one order of magnitude higher than the cavity power. Such a shock may have heated the gas in the southern region, as indicated by the temperature map. The shock may also explain the arc-like region of enriched gas seen in the iron abundance map, as this may be produced by a non-Maxwellian electron distribution near its front.Comment: 14 pages, 8 figures, accepted for publication in ApJ. Revised version including minor comments and expanded discussion (version with full resolution figures available at http://hea-www.harvard.edu/~mgitti/hcg62-gitti.pdf

Evolution of brown dwarf disks: A Spitzer survey in Upper Scorpius

We have carried out a Spitzer survey for brown dwarf (BD) disks in the ~5 Myr old Upper Scorpius (UpSco) star forming region, using IRS spectroscopy from 8 to 12\mu m and MIPS photometry at 24\mu m. Our sample consists of 35 confirmed very low mass members of UpSco. Thirteen objects in this sample show clear excess flux at 24\mu m, explained by dust emission from a circum-sub-stellar disk. Objects without excess emission either have no disks at all or disks with inner opacity holes of at least ~5 AU radii. Our disk frequency of 37\pm 9% is higher than what has been derived previously for K0-M5 stars in the same region (on a 1.8 sigma confidence level), suggesting a mass-dependent disk lifetime in UpSco. The clear distinction between objects with and without disks as well as the lack of transition objects shows that disk dissipation inside 5 AU occurs rapidly, probably on timescales of <~10^5 years. For the objects with disks, most SEDs are uniformly flat with flux levels of a few mJy, well modeled as emission from dusty disks affected by dust settling to the midplane, which also provides indirect evidence for grain growth. The silicate feature around 10\mu m is either absent or weak in our SEDs, arguing for a lack of hot, small dust grains. Compared with younger objects in Taurus, BD disks in UpSco show less flaring. Taken together, these results clearly demonstrate that we see disks in an advanced evolutionary state: Dust settling and grain growth are ubiquituous in circum-sub-stellar disks at ages of 5 Myr, arguing for planet forming processes in BD disks. For almost all our targets, results from high-resolution spectroscopy and high-spatial resolution imaging have been published before, thus providing a large sample of BDs for which information about disks, accretion, and binarity is available. (abridged)Comment: 39 pages, 7 figures, accepted for publication in Ap

De novo identification of complex traits associated with asthma

IntroductionAsthma is a heterogeneous inflammatory disease often associated with other complex phenotypes. Identifying asthma-associated diseases and uncovering the molecular mechanisms mediating their interaction can help detangle the heterogeneity of asthma. Network analysis is a powerful approach for untangling such inter-disease relationships.MethodsHere, we integrated information on physical contacts between common single nucleotide polymorphisms (SNPs) and gene expression with expression quantitative trait loci (eQTL) data from the lung and whole blood to construct two tissue-specific spatial gene regulatory networks (GRN). We then located the asthma GRN (level 0) within each tissue-specific GRN by identifying the genes that are functionally affected by asthma-associated spatial eQTLs. Curated protein interaction partners were subsequently identified up to four edges or levels away from the asthma GRN. The eQTLs spatially regulating genes on levels 0–4 were queried against the GWAS Catalog to identify the traits enriched (hypergeometric test; FDR ≤ 0.05) in each level.ResultsWe identified 80 and 82 traits significantly enriched in the lung and blood GRNs, respectively. All identified traits were previously reported to be comorbid or associated (positively or negatively) with asthma (e.g., depressive symptoms and lung cancer), except 8 traits whose association with asthma is yet to be confirmed (e.g., reticulocyte count). Our analysis additionally pinpoints the variants and genes that link asthma to the identified asthma-associated traits, a subset of which was replicated in a comorbidity analysis using health records of 26,781 asthma patients in New Zealand.DiscussionOur discovery approach identifies enriched traits in the regulatory space proximal to asthma, in the tissue of interest, without a priori selection of the interacting traits. The predictions it makes expand our understanding of possible shared molecular interactions and therapeutic targets for asthma, where no cure is currently available

Effect of Sodium-Glucose Cotransporter-2 Inhibitors on Endothelial Function: A Systematic Review of Preclinical Studies

IntroductionWhile the beneficial effects of sodium-glucose cotransporter-2 (SGLT-2) inhibitors on cardiovascular and renal outcomes are recognized, their direct effects on endothelial function remain unclear. We, therefore, undertook a systematic review to evaluate the current literature in this area.MethodsElectronic databases (PubMed, EMBASE, and Medline) were systematically searched using PRISMA guidelines for studies involving the in vitro, in vivo, or ex vivo administration of SGLT-2 inhibitors to animals, vascular tissue, or vascular endothelial cells.ResultsOf 144 retrieved publications, 24 experimental studies met the inclusion criteria. Reporting of possible sources of bias were poor, making the overall risk of bias difficult to assess. Within the 24 studies, the SGLT-2 inhibitors canagliflozin, ipragliflozin, empagliflozin, dapagliflozin, tofogliflozin, and luseogliflozin were assessed as interventions. Animal model studies (n = 17) demonstrated that all SGLT-2 inhibitors prevented endothelial dysfunction and enhanced endothelium-dependent vasorelaxation in diabetic and non-diabetic models. In vitro studies (n = 9) using human endothelial cells indicated a direct anti-inflammatory effect of dapagliflozin (1–100 nM) and canagliflozin, (10 µM), while empagliflozin (1 and 10 µM) improved viability of hyperglycemic cells. Potential mechanisms of action of the SGLT-2 inhibitors include a reduction in oxidative stress, modulation of adhesion molecules and reductions in pro-inflammatory cytokines.ConclusionsPreclinical studies indicate that SGLT-2 inhibitors attenuate vascular dysfunction in preclinical models via a combination of mechanisms that appear to act independently of glucose-lowering benefits