Empirical relations for the accurate estimation of stellar masses and radii

In this work, we have taken advantage of the most recent accurate stellar characterizations carried out using asteroseismology, eclipsing binaries and interferometry to evaluate a comprehensive set of empirical relations for the estimation of stellar masses and radii. We have gathered a total of 934 stars -- of which around two-thirds are on the Main Sequence -- that are characterized with different levels of precision, most of them having estimates of M, R, Teff, L, g, density, and [Fe/H]. We have deliberately used a heterogeneous sample (in terms of characterizing techniques and spectroscopic types) to reduce the influence of possible biases coming from the observation, reduction, and analysis methods used to obtain the stellar parameters. We have studied a total of 576 linear combinations of Teff, L, g, density, and [Fe/H] (and their logarithms) to be used as independent variables to estimate M or R. We have used an error-in-variables linear regression algorithm to extract the relations and to ensure the fair treatment of the uncertainties. We present a total of 38 new or revised relations that have an adj-R2 regression statistic higher than 0.85, and a relative accuracy and precision better than 10% for almost all the cases. The relations cover almost all the possible combinations of observables, ensuring that, whatever list of observables is available, there is at least one relation for estimating the stellar mass and radius.Comment: 49 Pages, 17 figures, 11 tables, accepted for publication in ApJ

Monitoring a high--amplitude Delta Sct star for 152 days: discovery of 12 additional modes and modulation effects in the light curve of CoRoT 101155310

The detection of small-amplitude nonradial modes in high-amplitude Delta Sct (HADS) variables has been very elusive until at least five of them were detected in the light curve of V974 Oph obtained from ground-based observations. The combination of radial and nonradial modes has a high asteroseismic potential, thanks to the strong constraints we can put in the modelling. The continuous monitoring of ASAS 192647-0030.0=CoRoT 101155310 (P=0.1258 d, V=13.4) ensured from space by the CoRoT (Convection, Rotation and planetary Transits) mission constitutes a unique opportunity to exploit such potential. The 22270 CoRoT measurements were performed in the chromatic mode. They span 152 d and cover 1208 consecutive cycles. After the correction for one jump and the long-term drift, the level of the noise turned out to be 29 micromag. The phase shifts and amplitude ratios of the coloured CoRoT data, the HARPS spectra, and the period-luminosity relation were used to determine a self-consistent physical model. In turn, it allowed us to model the oscillation spectrum, also giving feedback on the internal structure of the star. In addition to the fundamental radial mode f1=7.949 c/d with harmonics up to 10f1, we detected 12 independent terms. Linear combinations were also found and the light curve was solved by means of 61 frequencies (smallest amplitude 0.10 mmag). The newest result is the detection of a periodic modulation of the f1 mode (triplets at +/-0.193 c/d centred on f1 and 2f1), discussed as a rotational effect or as an extension of the Blazhko effect to HADS stars. The physical model suggests that CoRoT 101155310 is an evolved star, with a slight subsolar metallic abundance, close to the terminal age main sequence. All the 12 additional terms are identified with mixed modes in the predicted overstable region.Comment: 10 pages, 6 figures, Tables 1 and 2 available at CDS after publication. Accepted for publication in Astronomy and Astrophysic

Chronos - take the pulse of our galactic neighbourhood. After Gaia: Time domain information, masses and ages for stars

Understanding our Galaxy’s structure, formation, and evolution will, over the next decades, continue to benefit from the wonderful large survey by Gaia, for astrometric, kinematic, and spectroscopic characterization, and by large spectroscopic surveys for chemical characterization. The weak link for full exploitation of these data is age characterization, and stellar age estimation relies predominantly on mass estimates. The ideas presented in this White Paper shows that a seismology survey is the way out of this situation and a natural complement to existing and planned surveys. These ideas are strongly rooted in the past decade’s experience of the so-called Seismology revolution, initiated with CoRoT and Kepler. The case of red giant stars is used here as the best current illustration of what we can expect from seismology for large samples, but premises for similar developments exist in various other classes of stars covering other ranges of age or mass. Whatever the star considered, the first information provided by stellar pulsations is always related to the mean density and thus to the mass (and age). In order to satisfy the need for long-duration and allsky coverage, we rely on a new instrumental concept which decouples integration time and sampling time. We thus propose a long (~1 year) all-sky survey which would perfectly fit between TESS, PLATO, and the Rubin Observatory (previously known as LSST) surveys to offer a time domain complement to the current and planned astrometric and spectroscopic surveys. The fine characterization of host stars is also a key aspect for the interpretation and exploitation of the various projects – anticipated in the framework of the Voyage 2050 programme – searching for atmospheric characterization of terrestrial planets or, more specifically, looking for a signature of life, in distant planets

Structural, thermal, in vitro degradation and cytocompatibility properties of P2O5-B2O3-CaO-MgO-Na2O-Fe2O3 glasses

Borophosphate glasses with compositions of (48 − x)P2O5-(12 + x)B2O3-14CaO-20MgO-1Na2O-5Fe2O3 (where x = 0, 3, 8 mol%) were prepared via a melt-quenching process. The effects of replacing P2O5 with B2O3 on the structural, thermal, degradation properties and cytocompatibility were investigated. Fourier transform infrared (FTIR) spectroscopy analysis confirmed the existence of BO3 triangular units and BO4 tetrahedral units within all the glasses with an increase of B/P ratio from 0.25 to 0.5. The BO4 units within the glass structure were observed to cause an increase in density (ρ) as well as glass transition (Tg) temperature and to decrease the crystallisation temperature (Tc). A decrease in thermal stability which indicated by process window was also observed in the case of substitution of P2O5 with B2O3. Degradation analysis of the glasses indicated that the dissolution rate increased with the addition of B2O3. The decrease in the thermal stability and chemical durability were attributed to the increase of BO3 units, which could increase crystallisation tendency and be easily hydrolysed by solution. The effect of boron addition on the cytocompatibility of the glasses was analysed using Alamar Blue and alkaline phosphatase (ALP) assays and DNA quantification. MG63 osteosarcoma cells cultured in direct contact with the glass samples surface for 14 days showed better cytocompatibility, compared to the tissue culture plastic (TCP) control group. In summary, the glass formulation with 12 mol% B2O3 presented the best cytocompatibility and thermal stability, thus could be considered for continuous fibre fabrication in future research and downstream activities

Carbon-sensitive pedotransfer functions for plant available water

Currently accepted pedotransfer functions show negligible effect of management-induced changes to soil organic carbon (SOC) on plant available water holding capacity (θAWHC), while some studies show the ability to substantially increase θAWHC through management. The Soil Health Institute\u27s North America Project to Evaluate Soil Health Measurements measured water content at field capacity using intact soil cores across 124 long-term research sites that contained increases in SOC as a result of management treatments such as reduced tillage and cover cropping. Pedotransfer functions were created for volumetric water content at field capacity (θFC) and permanent wilting point (θPWP). New pedotransfer functions had predictions of θAWHC that were similarly accurate compared with Saxton and Rawls when tested on samples from the National Soil Characterization database. Further, the new pedotransfer functions showed substantial effects of soil calcareousness and SOC on θAWHC. For an increase in SOC of 10 g kg–1 (1%) in noncalcareous soils, an average increase in θAWHC of 3.0 mm 100 mm–1 soil (0.03 m3 m–3) on average across all soil texture classes was found. This SOC related increase in θAWHC is about double previous estimates. Calcareous soils had an increase in θAWHC of 1.2 mm 100 mm–1 soil associated with a 10 g kg–1 increase in SOC, across all soil texture classes. New equations can aid in quantifying benefits of soil management practices that increase SOC and can be used to model the effect of changes in management on drought resilience

Abstracts from the NIHR INVOLVE Conference 2017

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Linking soil microbial community structure to potential carbon mineralization: A continental scale assessment of reduced tillage

Potential carbon mineralization (Cmin) is a commonly used indicator of soil health, with greater Cmin values interpreted as healthier soil. While Cmin values are typically greater in agricultural soils managed with minimal physical disturbance, the mechanisms driving the increases remain poorly understood. This study assessed bacterial and archaeal community structure and potential microbial drivers of Cmin in soils maintained under various degrees of physical disturbance. Potential carbon mineralization, 16S rRNA sequences, and soil characterization data were collected as part of the North American Project to Evaluate Soil Health Measurements (NAPESHM). Results showed that type of cropping system, intensity of physical disturbance, and soil pH influenced microbial sensitivity to physical disturbance. Furthermore, 28% of amplicon sequence variants (ASVs), which were important in modeling Cmin, were enriched under soils managed with minimal physical disturbance. Sequences identified as enriched under minimal disturbance and important for modeling Cmin, were linked to organisms which could produce extracellular polymeric substances and contained metabolic strategies suited for tolerating environmental stressors. Understanding how physical disturbance shapes microbial communities across climates and inherent soil properties and drives changes in Cmin provides the context necessary to evaluate management impacts on standardized measures of soil microbial activity

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Cuentos de nunca acabar. Aproximaciones desde la interculturalidad

Cuentos de nunca acabar. Aproximaciones desde la interculturalidad, surge después de la pandemia y su imposibilidad de socializar “en persona” con los compañeros de eventuales encuentros, porque la Comprensión Lectora tenía que reinventarse para su nueva reflexión cognitiva, adaptación contextual y reconstrucción del conocimiento. Este renovado enfoque de la realidad postpandemia, concebido en el marco de la educación intercultural comunitaria, busca potencializar los entornos naturales, sociales y culturales como recursos de aprendizaje multidisciplinario a través del lenguaje animado de los cuentos. En este marco, había que dinamizar la asignatura de Comunicación Oral y Escrita, que se dicta en los Primeros Niveles de los Centros de Apoyo de Otavalo, Cayambe, Latacunga y Riobamba, mediante un eje transversal donde los estudiantes escriban fundamentados en valores de la cosmovisión andina, considerando que provienen de varios lugares de la sierra y amazonía ecuatoriana. Todo surgió del encuentro presencial de un sábado cualquiera donde los estudiantes realizaban ejercicios narrativos, logrando una apreciable respuesta de imaginación, más emotiva que la clásica tarea de las Unidades, tanto así que, pasados unos días, seguían llegando sus escritos a mi correo. Entonces nos pusimos manos a la obra, cada estudiante tendría dos opciones como Actividad Integradora, la primera consistía en escribir un cuento de su propia inspiración, y la segunda analizar un clásico para comentar sus valores y antivalores. La mayor parte de estudiantes decidió escribir su propio cuento, de donde se escogieron algunas participaciones que podrían considerarse originales, para una edición que, respetando la transcripción de la tradición oral que prima en los sectores comunitarios, nos concretamos en revisar la puntuación y ortografía para publicarlos. Con esto buscamos innovar la Actividad Integradora, por algo más práctico y operativo para configurar los Objetos de Aprendizaje que buscamos. Así nació, en medio del camino, este libro de Cuentos de nunca acabar. Aproximaciones desde la interculturalidad, que ponemos en sus manos. Hernán Hermosa Mantilla Quito, junio de 202

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK.

BACKGROUND: A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. METHODS: This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. FINDINGS: Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0-75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4-97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8-80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3-4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. INTERPRETATION: ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials. FUNDING: UK Research and Innovation, National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, Bill & Melinda Gates Foundation, Lemann Foundation, Rede D'Or, Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca