A low-mass planet candidate orbiting Proxima Centauri at a distance of 1.5 AU

Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).Our nearest neighbor, Proxima Centauri, hosts a temperate terrestrial planet. We detected in radial velocities evidence of a possible second planet with minimum mass m c sin i c = 5.8 ± 1.9 M ⊕ and orbital period P c = 5.21 - 0.22 + 0.26 years. The analysis of photometric data and spectro-scopic activity diagnostics does not explain the signal in terms of a stellar activity cycle, but follow-up is required in the coming years for confirming its planetary origin. We show that the existence of the planet can be ascertained, and its true mass can be determined with high accuracy, by combining Gaia astrometry and radial velocities. Proxima c could become a prime target for follow-up and characterization with next-generation direct imaging instrumentation due to the large maximum angular separation of ~1 arc second from the parent star. The candidate planet represents a challenge for the models of super-Earth formation and evolution.Peer reviewedFinal Published versio

The 2003-4 multisite photometric campaign for the Beta Cephei and eclipsing star 16 (EN) Lacertae with an Appendix on 2 Andromedae, the variable comparison star

A multisite photometric campaign for the Beta Cephei and eclipsing variable 16 Lacertae is reported. 749 h of high-quality differential photoelectric Stromgren, Johnson and Geneva time-series photometry were obtained with ten telescopes during 185 nights. After removing the pulsation contribution, an attempt was made to solve the resulting eclipse light curve by means of the computer program EBOP. Although a unique solution was not obtained, the range of solutions could be constrained by comparing computed positions of the secondary component in the Hertzsprung-Russell diagram with evolutionary tracks. For three high-amplitude pulsation modes, the uvy and the Geneva UBG amplitude ratios are derived and compared with the theoretical ones for spherical-harmonic degrees l <= 4. The highest degree, l = 4, is shown to be incompatible with the observations. One mode is found to be radial, one is l = 1, while in the remaining case l = 2 or 3. The present multisite observations are combined with the archival photometry in order to investigate the long-term variation of the amplitudes and phases of the three high-amplitude pulsation modes. The radial mode shows a non-sinusoidal variation on a time-scale of 73 yr. The l = 1 mode is a triplet with unequal frequency spacing, giving rise to two beat-periods, 720.7 d and 29.1 yr. The amplitude and phase of the l = 2 or 3 mode vary on time-scales of 380.5 d and 43 yr. The light variation of 2 And, one of the comparison stars, is discussed in the Appendix.Comment: 18 pages, 19 figures, accepted for publication in MNRA

Multisite photometry of the pulsating Herbig Ae star V346 Ori

CONTEXT: The study of pulsation in Pre--Main--Sequence intermediate-mass stars represents an important tool for deriving information on fundamental stellar parameters and internal structure, as well as for testing current theoretical models. Interest in this class of variable stars has significantly increased during the last decade and about 30 members are presently known in the literature. AIMS: We have constructed the frequency spectrum of the oscillations in V346 Ori. We apply asteroseismic tools to these data to estimate the intrinsic parameters (mass, luminosity, effective temperature) of V346 Ori and to obtain information on its internal structure. METHODS: CCD time series photometry in the Johnson V filter has been obtained for a total of 145.7 h of observations distributed over 36 nights. The resulting light curves have been subjected to a detailed frequency analysis using updated numerical techniques. Photometric and spectroscopic data have also been acquired to determine reliable estimates of the stellar properties. RESULTS: We have identified 13 oscillation frequencies, 6 of which with higher significance. These have been compared with the predictions of non-radial adiabatic models. The resulting best fit model has a mass of 2.1$\pm$0.2 $M_{\odot}$, luminosity $\log{L/L_{\odot}}=1.37^{+0.11}_{-0.13}$, and effective temperature 7300$\pm$200 K. These values are marginally consistent with the association of V346 Ori to Orion OB1a. Alternatively, V346 Ori could be placed at a slightly larger distance than previously estimated.Comment: Accepted for publication on A&A. 14 Pages, 11 Figure

Effect of serum phosphate on parathyroid hormone secretion during hemodialysis

Effect of serum phosphate on parathyroid hormone secretion during hemodialysis.BackgroundRecent studies have demonstrated that a high concentration of phosphate directly stimulates parathyroid hormone (PTH) secretion. High serum levels of phosphate are usually observed in patients with end-stage renal disease. The aim of the present study was to evaluate whether serum phosphate concentration had an acute effect on PTH secretion in hemodialysis patients. The levels of serum phosphate were manipulated during the hemodialysis session by using a phosphate free dialysate or a dialysate with a high content of phosphate.MethodsTen stable hemodialysis patients with PTH values above 300 pg/ml were included in the study. A PTH-calcium curve was obtained during both high phosphate and phosphate free hemodialysis.ResultsThe serum phosphate concentration remained high (2.17 ± 0.18mM) throughout the high phosphate hemodialysis and decreased progressively to normal levels (1.02 ± 0.06mM) during the phosphate free hemodialysis. The serum PTH levels at maximal inhibition by hypercalcemia (minimal PTH) were greater during the high phosphate than the phosphate free hemodialysis (413 ± 79 vs. 318 ± 76 pg/ml, P < 0.003). In all patients the values of minimum PTH were greater during the high phosphorus than the phosphorus free hemodialysis. The values of maximally stimulated PTH during hypocalcemia and the set point of the PTH-calcium curve were similar during the high phosphate and the phosphate free hemodialysis.ConclusionThe maintenance of high serum phosphorus levels during hemodialysis prevented, in part, the inhibition of PTH secretion by calcium, which strongly suggests that in hemodialysis patients high serum phosphate contributes directly to the elevation of PTH levels despite normal or high serum calcium concentration

The CARMENES search for exoplanets around M dwarfs: Two planets on opposite sides of the radius gap transiting the nearby M dwarf LTT 3780

Full list of authors: Nowak, G.; Luque, R.; Parviainen, H.; Pallé, E.; Molaverdikhani, K.; Béjar, V. J. S.; Lillo-Box, J.; Rodríguez-López, C.; Caballero, J. A.; Zechmeister, M.; Passegger, V. M.; Cifuentes, C.; Schweitzer, A.; Narita, N.; Cale, B.; Espinoza, N.; Murgas, F.; Hidalgo, D.; Zapatero Osorio, M. R.; Pozuelos, F. J.; Aceituno, F. J.; Amado, P. J.; Barkaoui, K.; Barrado, D.; Bauer, F. F.; Benkhaldoun, Z.; Caldwell, D. A.; Casasayas Barris, N.; Chaturvedi, P.; Chen, G.; Collins, K. A.; Collins, K. I.; Cortés-Contreras, M.; Crossfield, I. J. M.; de León, J. P.; Díez Alonso, E.; Dreizler, S.; El Mufti, M.; Esparza-Borges, E.; Essack, Z.; Fukui, A.; Gaidos, E.; Gillon, M.; Gonzales, E. J.; Guerra, P.; Hatzes, A.; Henning, Th.; Herrero, E.; Hesse, K.; Hirano, T.; Howell, S. B.; Jeffers, S. V.; Jehin, E.; Jenkins, J. M.; Kaminski, A.; Kemmer, J.; Kielkopf, J. F.; Kossakowski, D.; Kotani, T.; Kürster, M.; Lafarga, M.; Latham, D. W.; Law, N.; Lissauer, J. J.; Lodieu, N.; Madrigal-Aguado, A.; Mann, A. W.; Massey, B.; Matson, R. A.; Matthews, E.; Montañés-Rodríguez, P.; Montes, D.; Morales, J. C.; Mori, M.; Nagel, E.; Oshagh, M.; Pedraz, S.; Plavchan, P.; Pollacco, D.; Quirrenbach, A.; Reffert, S.; Reiners, A.; Ribas, I.; Ricker, G. R.; Rose, M. E.; Schlecker, M.; Schlieder, J. E.; Seager, S.; Stangret, M.; Stock, S.; Tamura, M.; Tanner, A.; Teske, J.; Trifonov, T.; Twicken, J. D.; Vanderspek, R.; Watanabe, D.; Wittrock, J.; Ziegler, C.; Zohrabi, F.We present the discovery and characterisation of two transiting planets observed by the Transiting Exoplanet Survey Satellite (TESS) orbiting the nearby (d∗ ≈ 22 pc), bright (J ≈ 9 mag) M3.5 dwarf LTT 3780 (TOI-732). We confirm both planets and their association with LTT 3780 via ground-based photometry and determine their masses using precise radial velocities measured with the CARMENES spectrograph. Precise stellar parameters determined from CARMENES high-resolution spectra confirm that LTT 3780 is a mid-M dwarf with an effective temperature of Teff = 3360 ± 51 K, a surface gravity of log g∗ = 4.81 ± 0.04 (cgs), and an iron abundance of [Fe/H] = 0.09 ± 0.16 dex, with an inferred mass of M∗ = 0.379 ± 0.016M· and a radius of R∗ = 0.382 ± 0.012R·. The ultra-short-period planet LTT 3780 b (Pb = 0.77 d) with a radius of 1.35-0.06+0.06 R·, a mass of 2.34-0.23+0.24 M·, and a bulk density of 5.24-0.81+0.94 g cm-3 joins the population of Earth-size planets with rocky, terrestrial composition. The outer planet, LTT 3780 c, with an orbital period of 12.25 d, radius of 2.42-0.10+0.10 R·, mass of 6.29-0.61+0.63 M·, and mean density of 2.45-0.37+0.44 g cm-3 belongs to the population of dense sub-Neptunes. With the two planets located on opposite sides of the radius gap, this planetary system is anexcellent target for testing planetary formation, evolution, and atmospheric models. In particular, LTT 3780 c is an ideal object for atmospheric studies with the James Webb Space Telescope (JWST). © 2020 ESO.CARMENES is an instrument for the Centro Astronomico Hispano-Aleman de Calar Alto (CAHA, Almeria, Spain). CARMENES is funded by the German Max-Planck-Gesellschaft (MPG), the Spanish Consejo Superior de Investigaciones Cientificas (CSIC), the European Union through FEDER/ERF FICTS-2011-02 funds, and the members of the CARMENES Consortium (Max-Planck-Institut fur Astronomie, Instituto de Astrofisica de Andalucia, Landessternwarte Konigstuhl, Institut de Ciencies de l'Espai, Institut fur Astrophysik Gottingen, Universidad Complutense de Madrid, Thuringer Landessternwarte Tautenburg, Instituto de Astrofisica de Canarias, Hamburger Sternwarte, Centro de Astrobiologia and Centro Astronomico Hispano-Aleman), with additional contributions by the Spanish Ministry of Economy, the German Science Foundation through the Major Research Instrumentation Programme and DFG Research Unit FOR2544 "Blue Planets around Red Stars", the Klaus Tschira Stiftung, the states of Baden-Wurttemberg and Niedersachsen, and by the Junta de Andalucia. This paper includes data collected by the TESS mission. Funding for the TESS mission is provided by the NASA Explorer Program. We acknowledge the use of public TOI Release data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This article is partly based on observations made with the MuSCAT2 instrument, developed by ABC, at Telescopio Carlos Sanchez operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide. This work makes use of observations from the LCOGT network. This work makes use of observations acquired with the T150 telescope at Sierra Nevada Observatory, operated by the Instituto de Astrofisica de Andalucia (IAACSIC). Some of the Observations in the paper made use of the High-Resolution Imaging instrument 'Alopeke at Gemini-North. `Alopeke was funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. IRD is operated by the Astrobiology Center of the National Institutes of Natural Sciences. The research leading to these results has received funding from the ARC grant for Concerted Research Actions, financed by the WalloniaBrussels Federation. TRAPPIST is funded by the Belgian Fund for Scientific Research (Fond National de la Recherche Scientifique, FNRS) under the grant FRFC 2.5.594.09.F, with the participation of the Swiss National Science Fundation (SNF). TRAPPIST-North is a project funded by the University of Liege (Belgium), in collaboration with Cadi Ayyad University of Marrakech (Morocco) M.G. and E.J. are F.R.S.-FNRS Senior Research Associate. The authors acknowledge funding from the Spanish Ministry of Economics and Competitiveness through projects PGC2018-098153-B-C31 and AYA2015-69350-C3-2-P. This work is partly supported by JSPS KAKENHI Grant Numbers JP18H01265 and JP18H05439, and JST PRESTO Grant Number JPMJPR1775. V.M.P. acknowledges support from NASA Grant NNX17AG24G. T.H. acknowledges support from the European Research Council under the Horizon 2020 Framework Program via the ERC Advanced Grant Origins 83 24 28. This research has been partially funded by Project No. MDM-2017-0737 Unidad de Excelencia "Maria de Maeztu" -Centro de Astrobiologia (INTA-CSIC). This research acknowledges financial support from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709) and project AYA2016-794425

Activation of p21 limits acute lung injury and induces early senescence after acid aspiration and mechanical ventilation

The p53/p21 pathway is activated in response to cell stress. However, its role in acute lung injury has not been elucidated. Acute lung injury is associated with disruption of the alveolo-capillary barrier leading to acute respiratory distress syndrome (ARDS). Mechanical ventilation may be necessary to support gas exchange in patients with ARDS, however, high positive airway pressures can cause regional overdistension of alveolar units and aggravate lung injury. Here, we report that acute lung injury and alveolar overstretching activate the p53/p21 pathway to maintain homeostasis and avoid massive cell apoptosis. A systematic pooling of transcriptomic data from animal models of lung injury demonstrates the enrichment of specific p53- and p21-dependent gene signatures and a validated senescence profile. In a clinically relevant, murine model of acid aspiration and mechanical ventilation, we observed changes in the nuclear envelope and the underlying chromatin, DNA damage and activation of the Tp53/p21 pathway. Absence of Cdkn1a decreased the senescent response, but worsened lung injury due to increased cell apoptosis. Conversely, treatment with lopinavir/ritonavir led to Cdkn1a overexpression and ameliorated cell apoptosis and lung injury. The activation of these mechanisms was associated with early markers of senescence, including expression of senescence-related genes and increases in senescence-associated heterochromatin foci in alveolar cells. Autopsy samples from lungs of patients with ARDS revealed increased senescence-associated heterochromatin foci. Collectively, these results suggest that acute lung injury activates p53/p21 as an anti-apoptotic mechanism to ameliorate damage, but with the side effect of induction of senescence

Cardiovascular risk factors and evolution of patients attended with COVID-19 in a National Reference Hospital from Lima, Peru

Introduction: Coronavirus disease 2019 (COVID-19) fatal outcomes have been associated with multiple cardiovascular risk factors. In new epidemic areas, such as Latin America, there is a lack of studies about this. Objectives: To evaluate demographic data, signs and symptoms during emergency arrival, prevalence of cardiovascular risk factors, laboratory and ECG findings and their influence in mortality, in a retrospective cohort of patients in a national reference hospital of Lima, Peru. Methods: Review the clinical records of the patients attended at Hospital Rebagliati Hospital during March 6th and April 30th, 2020, using rRT-PCR was used for the detection of the RNA of SARS-CoV-2 following the protocol Charité, Berlin, Germany, from nasopharyngeal swabs at the National Institute of Health. Bivariate analysis and multivariate analysis using logistic regression was done. Values of p &lt; 0.05 were considered significant for all analyses. Results: One hundred six hospitalized patients were evaluated. The mean age of patients was 61.58 years (SD 16.81). Cardiovascular risk factors among them were hypertension (46.2%), diabetes (28.3%), and obesity (28.3%), among others. Fifty-six patients died (52.8%). Mortality associated factors at the multivariate analysis were arterial hypertension (OR=1.343, 95% 1.089-1.667), myocardial injury (OR=1.303, 95% 1.031-1.642), and mechanical ventilation (OR 1.262, 95% 1.034-1.665), as associated factors. Conclusion: Cardiovascular risk factors and cardiovascular signs or symptoms are common during emergency arrival in patients with COVID-19. Arterial hypertension, myocardial injury and mechanical ventilation were associated with mortality in multivariate analysis, as observed in other regions of the world.Introducción: Los desenlaces fatales de la enfermedad por coronavirus 2019 (COVID-19) se han asociado con múltiples factores de riesgo cardiovascular. En nuevas áreas epidémicas, como América Latina, faltan estudios al respecto. Objetivos: Evaluar datos demográficos, signos y síntomas durante la ingreso a emergencia, prevalencia de factores de riesgo cardiovascular, hallazgos de laboratorio y ECG y su influencia en la mortalidad, en una cohorte retrospectiva de pacientes en un hospital nacional de referencia de Lima, Perú. Métodos: Se revisaron las historias clínicas de los pacientes atendidos en el Hospital Nacional Edgardo Rebagliati durante los días 6 de marzo y 30 de abril de 2020, se utilizó rRT-PCR para la detección del ARN del SARS-CoV-2 siguiendo el protocolo Charité, Berlín, Alemania de hisopos nasofaríngeos en el Instituto Nacional de Salud. Se realizó análisis bivariado y análisis multivariado mediante regresión logística. Los valores de p &lt;0,05 se consideraron significativos para todos los análisis. Resultados: Se evaluaron ciento seis pacientes hospitalizados. La edad media de los pacientes fue de 61,58 años (DE 16,81). Los factores de riesgo cardiovascular entre ellos fueron hipertensión (46,2%), diabetes (28,3%) y obesidad (28,3%), entre otros. Fallecieron 56 pacientes (52,8%). Los factores asociados a la mortalidad en el análisis multivariado fueron hipertensión arterial (OR = 1.343, 95% 1.089-1.667), lesión miocárdica (OR = 1.303, 95% 1.031-1.642) y ventilación mecánica (OR 1.262, 95% 1.034-1.665), como factores asociados. Conclusión: Los factores de riesgo cardiovascular y los signos o síntomas cardiovasculares son comunes durante la llegada de emergencia en pacientes con COVID-19. La hipertensión arterial, la lesión miocárdica y la ventilación mecánica se asociaron con la mortalidad en el análisis multivariado, como se observó en otras regiones del mundo