254 research outputs found

    Super star cluster feedback driving ionization, shocks and outflows in the halo of the nearby starburst ESO 338-IG04

    Full text link
    Stellar feedback strongly affects the interstellar medium (ISM) of galaxies. Stellar feedback in the first galaxies likely plays a major role in enabling the escape of LyC photons, which contribute to the re-ionization of the Universe. Nearby starburst galaxies serve as local analogues allowing for a spatially resolved assessment of the feedback processes in these galaxies. We characterize the feedback effects from the star clusters in the local high-redshift analogue ESO 338-IG04 on the ISM and compare the results with the properties of the most massive clusters. We use high quality VLT/MUSE optical integral field data to derive the physical properties of the ISM such as ionization, density, shocks, and perform new fitting of the spectral energy distributions of the brightest clusters in ESO 338-IG04 from HST imaging. ESO 338-IG04 has a large ionized halo which we detect to a distance of 9 kpc. We identify 4 Wolf-Rayet (WR) clusters based on the blue and red WR bump. We follow previously identified ionization cones and find that the ionization of the halo increases with distance. Analysis of the galaxy kinematics shows two complex outflows driven by the numerous young clusters in the galaxy. We find a ring of shocked emission traced by an enhanced [OI]/Hα\alpha ratio surrounding the starburst and at the end of the outflow. Finally we detect nitrogen enriched gas associated with the outflow, likely caused by the WR stars in the massive star clusters. Photo-ionization dominates the central starburst and sets the ionization structure of the entire halo, resulting in a density bounded halo, facilitating the escape of LyC photons. Outside the central starburst, shocks triggered by an expanding super bubble become important. The shocks at the end of the outflow suggest interaction between the hot outflowing material and the more quiescent halo gas.Comment: Accepted for publication in Astronomy and Astrophysics, 22 pages, 15 figure

    Short Text Messages to Motivate HIV Testing Among Men Who have Sex with Men: A Qualitative Study in Lima, Peru

    Get PDF
    Objective: The objective of this study is to identify features and content that short message service (SMS) should have in order to motivate HIV testing among men who have sex with men (MSM) in Lima, Peru. Methods: From October, 2010 to February, 2011, we conducted focus groups at two stages; six focus groups were conducted to explore and identify SMS content and features and two additional focus groups were conducted to tailor SMS content. The text messages were elaborated within the theoretical framework of the Information-Motivation-Behavioral Skills model and the Social Support Theory. Results: A total of 62 individuals participated in the focus groups. The mean age of participants was 28 years (range 18-39). We identified important features and content items needed for the successful delivery of text messages, including: a) the use of neutral and coded language; b) appropriate frequency and time of delivery; c) avoiding mass and repetitive messages; and d) use of short, concise and creative messages. Although in Peru receiving text messages is usually a free service, it is important to remind participants that receiving messages will be free of charge. Conclusion: Text messages can be used to promote HIV testing among Peruvian MSM. It is important to consider adequate frequency, message content and cost when delivering messages to promote HIV testing in this population

    Noninvasive rapid cardiac magnetic resonance for the assessment of cardiomyopathies in low-middle income countries

    Get PDF
    INTRODUCTION: Cardiac Magnetic Resonance (CMR) is a crucial diagnostic imaging test that redefines diagnosis and enables targeted therapies, but the access to CMR is limited in low-middle Income Countries (LMICs) even though cardiovascular disease is an emergent primary cause of mortality in LMICs. New abbreviated CMR protocols can be less expensive, faster, whilst maintaining accuracy, potentially leading to a higher utilization in LMICs. AREAS COVERED: This article will review cardiovascular disease in LMICs and the current role of CMR in cardiac diagnosis and enable targeted therapy, discussing the main obstacles to prevent the adoption of CMR in LMICs. We will then review the potential utility of abbreviated, cost-effective CMR protocols to improve cardiac diagnosis and care, the clinical indications of the exam, current evidence and future directions. EXPERT OPINION: Rapid CMR protocols, provided that they are utilized in potentially high yield cases, could reduce cost and increase effectiveness. The adoption of these protocols, their integration into care pathways, and prioritizing key treatable diagnoses can potentially improve patient care. Several LMIC countries are now pioneering these approaches and the application of rapid CMR protocols appears to have a bright future if delivered effectively

    The invisible enemy : Understanding bird-window strikes through citizen science in a focal city

    Get PDF
    Bird-window collisions have been estimated to be among the most important sources of bird death. Despite increasing knowledge in Latin America, our understanding of this phenomenon is still incipient, with research performed in Mexico limited to a handful of studies. Here, we present the results of a citizen science effort focused on bird-window collisions at seven buildings in the university campus of the National School of Higher Studies (ENES) of the National Autonomous University of Mexico, located in the city of Leon (central Mexico). Our main goal was to describe seasonal patterns of bird-window collisions and their relationship with building traits (i.e., building height, window area) through citizen science monitoring strategies. Our results showed that collisions were higher in two of the seven studied buildings, with two bird species recording almost half of the total collisions: Clay-colored Sparrow (Spizella pallida) and Indigo Bunting (Passerina cyanea). Seasonally, April was the only month to differ from the rest of the studied months, showing significantly higher rate of bird-window collision. Regarding building traits, only building height was related to the number of recorded bird-window collisions. In sum, our study provides findings from an understudied area, showing the value of citizen science approaches to generate knowledge on a deadly phenomenon. Notably, besides the potential drawbacks and importance of generating this kind of information, our project raised awareness on the topic across the entire campus community, from the students and academics to the administration, highlighting the potential for social impact with these kinds of projects.Peer reviewe

    Unveiling the gravitationally unstable disc of a massive star-forming galaxy using NOEMA and MUSE

    Full text link
    Using new high-resolution data of CO (2-1), H-alpha and H-beta obtained with the Northern Extended Millimeter Array (NOEMA) and the Multi-Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope, we have performed a Toomre-Q disc stability analysis and studied star formation, gas depletion times and other environmental parameters on sub-kpc scales within the z~0 galaxy SDSS J125013.84+073444.5 (LARS 8). The galaxy hosts a massive, clumpy disc and is a proto-typical analogue of main-sequence galaxies at z~1-2. We show that the massive (molecular) clumps in LARS 8 are the result of an extremely gravitationally unstable gas disc, with large scale instabilities found across the whole extent of the rotating disc, with only the innermost 500 pc being stabilized by its bulgelike structure. The radial profiles further reveal that - contrary to typical disc galaxies - the molecular gas depletion time decreases from more than 1 Gyr in the center to less than ~100 Myr in the outskirts of the disc, supporting the findings of a Toomre-unstable disc. We further identified and analysed 12 individual massive molecular clumps. They are virialized and follow the mass-size relation, indicating that on local (cloud/clump) scales the stars form with efficiencies comparable to those in Milky Way clouds. The observed high star formation rate must thus be the result of triggering of cloud/clump formation over large scales due to disc instability. Our study provides evidence that "in-situ" massive clump formation (as also observed at high redshifts) is very efficiently induced by large-scale instabilities.Comment: Submitted to MNRA

    Reappraising myocardial fibrosis in severe aortic stenosis: an invasive and non-invasive study in 133 patients

    Get PDF
    Aims: To investigate myocardial fibrosis (MF) in a large series of severe aortic stenosis (AS) patients using invasive biopsy and non-invasive imaging. Methods and results: One hundred thirty-three patients with severe, symptomatic AS accepted for surgical aortic valve replacement underwent cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) and extracellular volume fraction (ECV) quantification. Intra-operative left ventricular (LV) biopsies were performed by needle or scalpel, yielding tissue with (n = 53) and without endocardium (n = 80), and compared with 10 controls. Myocardial fibrosis occurred in three patterns: (i) thickened endocardium with a fibrotic layer; (ii) microscopic scars, with a subendomyocardial predominance; and (iii) diffuse interstitial fibrosis. Collagen volume fraction (CVF) was elevated (P < 0.001) compared with controls, and higher (P < 0.001) in endocardium-containing samples with a decreasing CVF gradient from the subendocardium (P = 0.001). Late gadolinium enhancement correlated with CVF (P < 0.001) but not ECV. Both LGE and ECV correlated independently (P < 0.001) with N-terminal pro-brain natriuretic peptide and high-sensitivity-troponin T. High ECV was also associated with worse LV remodelling, left ventricular ejection fraction and functional capacity. Combining high ECV and LGE better identified patients with more adverse LV remodelling, blood biomarkers and histological parameters, and worse functional capacity than each parameter alone. Conclusion: Myocardial fibrosis in severe AS is complex, but three main patterns exist: endocardial fibrosis, microscars (mainly in the subendomyocardium), and diffuse interstitial fibrosis. Neither histological CVF nor the CMR parameters ECV and LGE capture fibrosis in its totality. A combined, multi-parametric approach with ECV and LGE allows best stratification of AS patients according to the response of the myocardial collagen matrix

    Vav proteins are key regulators of Card9 signaling for innate antifungal immunity

    Get PDF
    Fungal infections are major causes of morbidity and mortality, especially in immunocompromised individuals. The innate immune system senses fungal pathogens through Syk-coupled C-type lectin receptors (CLRs), which signal through the conserved immune adaptor Card9. Although Card9 is essential for antifungal defense, the mechanisms that couple CLR-proximal events to Card9 control are not well defined. Here, we identify Vav proteins as key activators of the Card9 pathway. Vav1, Vav2, and Vav3 cooperate downstream of Dectin-1, Dectin-2, and Mincle to engage Card9 for NF-ÎșB control and proinflammatory gene transcription. Although Vav family members show functional redundancy, Vav1/2/3(-/-) mice phenocopy Card9(-/-) animals with extreme susceptibility to fungi. In this context, Vav3 is the single most important Vav in mice, and a polymorphism in human VAV3 is associated with susceptibility to candidemia in patients. Our results reveal a molecular mechanism for CLR-mediated Card9 regulation that controls innate immunity to fungal infections

    Immunosuppression-independent role of regulatory T cells against hypertension-driven renal dysfunctions

    Get PDF
    Hypertension-associated cardiorenal diseases represent one of the heaviest burdens for current health systems. In addition to hemodynamic damage, recent results have revealed that hematopoietic cells contribute to the development of these diseases by generating proinflammatory and profibrotic environments in the heart and kidney. However, the cell subtypes involved remain poorly characterized. Here we report that CD39+ regulatory T (TREG) cells utilize an immunosuppression-independent mechanism to counteract renal and possibly cardiac damage during angiotensin II (AngII)-dependent hypertension. This mechanism relies on the direct apoptosis of tissue-resident neutrophils by the ecto-ATP diphosphohydrolase activity of CD39. In agreement with this, experimental and genetic alterations in TREG/TH cell ratios have a direct impact on tissue-resident neutrophil numbers, cardiomyocyte hypertrophy, cardiorenal fibrosis, and, to a lesser extent, arterial pressure elevation during AngII-driven hypertension. These results indicate that TREG cells constitute a first protective barrier against hypertension-driven tissue fibrosis and, in addition, suggest new therapeutic avenues to prevent hypertension-linked cardiorenal diseases.This work has been supported by grants from the Castilla-LeĂłn Autonomous Government (CSI101U13), the Spanish Ministry of Economy and Competitiveness (SAF2012-31371, RD12/0036/0002), Worldwide Cancer Research, the SolĂłrzano Foundation, and the RamĂłn Areces Foundation to X.R.B. P.M. is funded by the Spanish Ministry of Economy and Competitiveness (SAF2011-27330). S.F., M.M.-M., J.R.-V., and A.M.-M. were supported by the Spanish Ministry of Economy and Competitiveness through BES-2010-031386, CSIC JAE-Doc, Juan de la Cierva, and BES-2009-016103 contracts, respectively. Spanish government-sponsored funding to X.R.B. is partially supported by the European Regional Development Fund.Peer Reviewe
    • 

    corecore