The ISLANDS project I: Andromeda XVI, An Extremely Low Mass Galaxy not Quenched by Reionization

Based on data aquired in 13 orbits of HST time, we present a detailed evolutionary history of the M31 dSph satellite Andromeda XVI, including its life-time star formation history, the spatial distribution of its stellar populations, and the properties of its variable stars. And XVI is characterized by prolonged star formation activity from the oldest epochs until star formation was quenched ~6 Gyr ago, and, notably, only half of the mass in stars of And XVI was in place 10 Gyr ago. And XVI appears to be a low mass galaxy for which the early quenching by either reionization or starburst feedback seems highly unlikely, and thus, is most likely due to an environmental effect (e.g., an interaction), possibly connected to a late infall in the densest regions of the Local Group. Studying the star formation history as a function of galactocentric radius, we detect a mild gradient in the star formation history: the star formation activity between 6 and 8 Gyr ago is significantly stronger in the central regions than in the external regions, although the quenching age appears to be the same, within 1 Gyr. We also report the discovery of 9 RR Lyrae stars, 8 of which belong to And XVI. The RR Lyrae stars allow a new estimate of the distance, (m-M)0= 23.72+/-0.09 mag, which is marginally larger than previous estimates based on the tip of the red giant branch.Comment: Accepted for publication on Ap

Temporal and spatial variations of CO2 diffuse volcanic degassing on Cuicocha Caldera Lake – Ecuador

Cuicocha Caldera is the youngest eruptive center of Cotacachi-Cuicocha Volcanic Complex, located at the north of Ecuador. The caldera contains a lake of 3.95 km2 surface, and a maximum depth of 148 m. Cuicocha Lake is characterized by the presence of CO2 gaseous diffuse emissions, perceptible as bubbling zones. Since 2011, CO2 diffuse flux measurements have been performed in this lake using the accumulation chamber method. The data obtained from twenty surveys were processed by means of the Graphical Statistical Approach and the Sequential Gaussian Simulation. The results reveal that Cuicocha lake has released a total estimated amount of ~400 kt of CO2 in the period between March 2011 and May 2019, with an average rate of 135 t/day. Furthermore, the spatial and temporal analysis of the data made possible the understanding of the processes occurring in the lake: 1) Lake stratification caused by the seasons seem to favor CO2 accumulation in the hipolimnion and its posterior releasing. Minimum total flux values of ~50 t/day have been estimated during “warm” stratified periods and maximum flux values of ~170 t/day have been recorded during “cold” overturn periods. Additionally, at least two anomalous degassing episodes were identified in 2012–2013, seemingly associated to changes in the volcanic activity also detected through seismicity. 2) Cuicocha CO2 degassing seems to be controlled by the existence of diffuse degassing structures at the lake bottom, which correspond to high permeability zones resulting from the intersection between ~NE-SW and ~WNW-ESE oriented structures. We propose a conceptual model to explain the systematic apparition of CO2 anomalies on specific areas of the lake surface.Fil: Sierra Vaca, Daniel Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Instituto Geofísico de la Escuela Politécnica Nacional; EcuadorFil: Hidalgo, Silvana. Instituto Geofísico de la Escuela Politécnica Nacional; EcuadorFil: Almeida, Marco. Instituto Geofísico de la Escuela Politécnica Nacional; EcuadorFil: Vigide, Nicolás Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Lamberti, María Clara Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Proaño, Antonio. Instituto Geofísico de la Escuela Politécnica Nacional; EcuadorFil: Narváez, Diego F.. Instituto Geofísico de la Escuela Politécnica Nacional; Ecuado

The ACS LCID project. X. The Star Formation History of IC 1613: Revisiting the Over-Cooling Problem

We present an analysis of the star formation history (SFH) of a field near the half light radius in the Local Group dwarf irregular galaxy IC 1613 based on deep Hubble Space Telescope Advanced Camera for Surveys imaging. Our observations reach the oldest main sequence turn-off, allowing a time resolution at the oldest ages of ~1 Gyr. Our analysis shows that the SFH of the observed field in IC 1613 is consistent with being constant over the entire lifetime of the galaxy. These observations rule out an early dominant episode of star formation in IC 1613. We compare the SFH of IC 1613 with expectations from cosmological models. Since most of the mass is in place at early times for low mass halos, a naive expectation is that most of the star formation should have taken place at early times. Models in which star formation follows mass accretion result in too many stars formed early and gas mass fractions which are too low today (the "over-cooling problem"). The depth of the present photometry of IC 1613 shows that, at a resolution of ~1 Gyr, the star formation rate is consistent with being constant, at even the earliest times, which is difficult to achieve in models where star formation follows mass assembly.Comment: 13 pages, 12 figures, accepted for publication in the Ap

The ISLAndS project II: The Lifetime Star Formation Histories of Six Andromeda dSphs

The Initial Star formation and Lifetimes of Andromeda Satellites (ISLAndS) project uses Hubble Space Telescope imaging to study a representative sample of six Andromeda dSph satellite companion galaxies. The main goal of the program is to determine whether the star formation histories (SFHs) of the Andromeda dSph satellites demonstrate significant statistical differences from those of the Milky Way, which may be attributable to the different properties of their local environments. Our observations reach the oldest main sequence turn-offs, allowing a time resolution at the oldest ages of ~ 1 Gyr, which is comparable to the best achievable resolution in the MW satellites. We find that the six dSphs present a variety of SFHs that are not strictly correlated with luminosity or present distance from M31. Specifically, we find a significant range in quenching times (lookback times from 9 to 6 Gyr), but with all quenching times more than ~ 6 Gyr ago. In agreement with observations of Milky Way companions of similar mass, there is no evidence of complete quenching of star formation by the cosmic UV background responsible for reionization, but the possibility of a degree of quenching at reionization cannot be ruled out. We do not find significant differences between the SFHs of the three members of the vast, thin plane of satellites and the three off-plane dSphs. The primary difference between the SFHs of the ISLAndS dSphs and Milky Way dSph companions of similar luminosities and host distances is the absence of very late quenching (< 5 Gyr ago) dSphs in the ISLAndS sample. Thus, models that can reproduce satellite populations with and without late quenching satellites will be of extreme interest.Comment: 24 pages, 11 figures, 3 tables, submitted to the Ap

Key processes for Cheirolophus (Asteraceae) diversification on oceanic islands inferred from AFLP data

The radiation of the genus Cheirolophus (Asteraceae) in Macaronesia constitutes a spectacular case of rapid diversification on oceanic islands. Twenty species - nine of them included in the IUCN Red List of Threatened Species - have been described to date inhabiting the Madeiran and Canarian archipelagos. A previous phylogenetic study revealed that the diversification of Cheirolophus in Macaronesia started less than 2 Ma. As a result of such an explosive speciation process, limited phylogenetic resolution was reported, mainly due to the low variability of the employed molecular markers. In the present study, we used highly polymorphic AFLP markers to i) evaluate species' boundaries, ii) infer their evolutionary relationships and iii) investigate the patterns of genetic diversity in relation to the potential processes likely involved in the radiation of Cheirolophus. One hundred and seventy-two individuals representing all Macaronesian Cheirolophus species were analysed using 249 AFLP loci. Our results suggest that geographic isolation played an important role in this radiation process. This was likely driven by the combination of poor gene flow capacity and a good ability for sporadic long-distance colonisations. In addition, we also found some traces of introgression and incipient ecological adaptation, which could have further enhanced the extraordinary diversification of Cheirolophus in Macaronesia. Last, we hypothesize that current threat categories assigned to Macaronesian Cheirolophus species do not reflect their respective evolutionary relevance, so future evaluations of their conservation status should take into account the results presented here

A pragmatic randomized trial of mailed fecal immunochemical testing to increase colorectal cancer screening among low‐income and minoritized populations

BackgroundColorectal cancer (CRC) screening is underused, particularly among low-income and minoritized populations, for whom the coronavirus disease 2019 (COVID-19) pandemic has challenged progress in achieving equity.MethodsA hub-and-spoke model was used. The hub was a nonacademic organization and the spokes were three community health center (CHC) systems overseeing numerous clinic sites. Via a cluster-randomized trial design, nine clinic sites were randomized to intervention and 16 clinic sites were randomized to usual care. Patient-level interventions included invitation letters, mailed fecal immunochemical tests (FITs), and call/text-based reminders. Year 1 intervention impact, which took place during the COVID-19 pandemic, was assessed as the proportion completing screening among individuals not up to date at baseline, which compared intervention and nonintervention clinics accounting for intraclinic cluster variation; confidence intervals (CIs) around differences not including 0 were interpreted as statistically significant.ResultsAmong 26,736 patients who met eligibility criteria, approximately 58% were female, 55% were Hispanic individuals, and 44% were Spanish speaking. The proportion completing screening was 11.5 percentage points (ppts) (95% CI, 6.1-16.9 ppts) higher in intervention versus usual care clinics. Variation in differences between intervention and usual care clinics was observed by sex (12.6 ppts [95% CI, 7.2-18.0 ppts] for females; 8.8 ppts [95% CI, 4.7-13.9 ppts] for males) and by racial and ethnic group (13.8 ppts [95% CI, 7.0-20.6 ppts] for Hispanic individuals; 13.0 ppts [95% CI, 3.6-22.4 ppts] for Asian individuals; 11.3 ppts [95% CI, 5.8-16.8 ppts] for non-Hispanic White individuals; 6.1 ppts [95% CI, 0.8-10.4 ppts] for Black individuals).ConclusionsA regional mailed FIT intervention was effective for increasing CRC screening rates across CHC systems serving diverse, low-income populations

Human influenza A virus causes myocardial and cardiac-specific conduction system infections associated with early inflammation and premature death.

Human influenza A virus (hIAV) infection is associated with important cardiovascular complications, although cardiac infection pathophysiology is poorly understood. We aimed to study the ability of hIAV of different pathogenicity to infect the mouse heart, and establish the relationship between the infective capacity and the associated in vivo, cellular and molecular alterations. We evaluated lung and heart viral titres in mice infected with either one of several hIAV strains inoculated intranasally. 3D reconstructions of infected cardiac tissue were used to identify viral proteins inside mouse cardiomyocytes, Purkinje cells, and cardiac vessels. Viral replication was measured in mouse cultured cardiomyocytes. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were used to confirm infection and study underlying molecular alterations associated with the in vivo electrophysiological phenotype. Pathogenic and attenuated hIAV strains infected and replicated in cardiomyocytes, Purkinje cells, and hiPSC-CMs. The infection was also present in cardiac endothelial cells. Remarkably, lung viral titres did not statistically correlate with viral titres in the mouse heart. The highly pathogenic human recombinant virus PAmut showed faster replication, higher level of inflammatory cytokines in cardiac tissue and higher viral titres in cardiac HL-1 mouse cells and hiPSC-CMs compared with PB2mut-attenuated virus. Correspondingly, cardiac conduction alterations were especially pronounced in PAmut-infected mice, associated with high mortality rates, compared with PB2mut-infected animals. Consistently, connexin43 and NaV1.5 expression decreased acutely in hiPSC-CMs infected with PAmut virus. YEM1L protease also decreased more rapidly and to lower levels in PAmut-infected hiPSC-CMs compared with PB2mut-infected cells, consistent with mitochondrial dysfunction. Human IAV infection did not increase myocardial fibrosis at 4-day post-infection, although PAmut-infected mice showed an early increase in mRNAs expression of lysyl oxidase. Human IAV can infect the heart and cardiac-specific conduction system, which may contribute to cardiac complications and premature death.JV is a PhD fellow of the La Caixa Foundation International Fellowship Programme (La Caixa/CNB). This work was supported by the European Molecular Biology Organizat ion (STF-7649 to AF), the Spanish Ministry of Science, Innovation and Universities (MCIU), (BFU2011-26175 and BFU2014-57797-R to AN), and the network Ciber de Enfermedades Respiratorias (CIBERES) including the Improvement and Mobilit y Programme. The CNIC is a Severo Ochoa Center of Excellence (SEV-2015-0505). CNIC is supported by MCIU and the Pro CNIC Foundation. This study was supported by grants from Fondo Europeo de Desarrollo Regional (CB16/11/00458), grants SAF2015-65607-R and SAF2016-80324-R from MCIU (A.H. and D.F-R.) and fellowship SVP-2014-068595 to J.A.N-A. This study was supported by Frankel Cardiovascular Centre, Michigan Medicine (Grant 332475). JJ is supported in part by the National Heart, Lung, and Blood Institute (R01 Grant HL122352). S.F.N is supported in part by the National Heart, Lung, and Blood Institute grants R21HL138064 and R01HL129136.S

Effects of a laboratory-based aerobic exercise intervention on brain volume and cardiovascular health markers: protocol for a randomised clinical trial

INTRODUCTION: Physical activity (PA) has beneficial effects on brain health and cardiovascular disease (CVD) risk. Yet, we know little about whether PA-induced changes to physiological mediators of CVD risk influence brain health and whether benefits to brain health may also explain PA-induced improvements to CVD risk. This study combines neurobiological and peripheral physiological methods in the context of a randomised clinical trial to better understand the links between exercise, brain health and CVD risk. METHODS AND ANALYSIS: In this 12-month trial, 130 healthy individuals between the ages of 26 and 58 will be randomly assigned to either: (1) moderate-intensity aerobic PA for 150 min/week or (2) a health information control group. Cardiovascular, neuroimaging and PA measurements will occur for both groups before and after the intervention. Primary outcomes include changes in (1) brain structural areas (ie, hippocampal volume); (2) systolic blood pressure (SBP) responses to functional MRI cognitive stressor tasks and (3) heart rate variability. The main secondary outcomes include changes in (1) brain activity, resting state connectivity, cortical thickness and cortical volume; (2) daily life SBP stress reactivity; (3) negative and positive affect; (4) baroreflex sensitivity; (5) pulse wave velocity; (6) endothelial function and (7) daily life positive and negative affect. Our results are expected to have both mechanistic and public health implications regarding brain-body interactions in the context of cardiovascular health. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the University of Pittsburgh Institutional Review Board (IRB ID: 19020218). This study will comply with the NIH Data Sharing Policy and Policy on the Dissemination of NIH-Funded Clinical Trial Information and the Clinical Trials Registration and Results Information Submission rule. TRIAL REGISTRATION NUMBER: NCT03841669

How Typical Are The Local Group Dwarf Galaxies?

We compare the cumulative star formation histories (SFHs) of Local Group (LG) dwarf galaxies with those in the volume-limited ACS Nearby Galaxy Survey Treasury (ANGST) sample (D < 4 Mpc), in order to understand how typical the LG dwarf galaxies are relative to those in the nearby universe. The SFHs were derived in a uniform manner from high quality optical color-magnitude diagrams constructed from Hubble Space Telescope imaging. We find that the {\it mean} cumulative SFHs of the LG dwarfs are comparable to the mean cumulative SFHs of the ANGST sample for the three different morphological types (dwarf spheroidals/ellipticals: dSph/dE; dwarf irregulars: dI; transition dwarfs: dTrans). We also discuss effects such as population gradients and systematic uncertainties in the stellar models that may influence the derived SFHs. Both the ANGST and Local Group dwarf galaxies show a consistent and strong morphology-density relationship, emphasizing the importance of environment in the evolution of dwarf galaxies. Specifically, we confirm that dIs are found at lower densities and higher luminosities than dSphs, within this large sample. We also find that dTrans are located in similar environments to those occupied by dwarf irregular galaxies, but have systematically lower luminosities that are more comparable to those of dwarf spheroidals. The similarity of the SFHs and morphology-density relationships of the LG and ANGST dwarf galaxies suggests that the LG dwarfs are a good representation of dwarf galaxies in the local universe.Comment: 10 pages, 4 figures. Accepted to Ap