Pyaneti: a fast and powerful software suite for multi-planet radial velocity and transit fitting

Transiting exoplanet parameter estimation from time-series photometry and Doppler spectroscopy is fundamental to study planets' internal structures and compositions. Here we present the code pyaneti, a powerful and user-friendly software suite to perform multi-planet radial velocity and transit data fitting. The code uses a Bayesian approach combined with an MCMC sampling to estimate the parameters of planetary systems. We combine the numerical efficiency of FORTRAN, the versatility of PYTHON, and the parallelization of OpenMP to make pyaneti a fast and easy to use code. The package is freely available at https://github.com/oscaribv/pyaneti.Comment: 15 pages, 6 figures, 2 tables. Accepted for publication in MNRA

Material nonlinear analysis of steel fibre reinforced concrete beams failing in shear

Experimental research has pointed out that fibre reinforcement gives valuable contribution for the shear strength of concrete beams. To obtain data to check the validity of the formulation proposed by RILEM TC 162-TDF for the evaluation of the fibres contribution for the concrete shear strength, sets of concrete beams were tested experimentally. To simulate the behaviour of this kind of structures, a computational code was developed, based on the finite element techniques. An accurate simulation of the behaviour of structures failing in a brittle mode, such is the case of the beams failing in shear, is a true challenge in the computational mechanics domain. To reproduce with enough accuracy the fracturing process of this type of elements, a multifixed crack model is implemented. The ability of the post-cracking stress-strain diagram proposed by RILEM TC 162-TDF to simulate the crack propagation is checked. A strain softening trilinear diagram is also derived from inverse analysis using the force-deflection relationship obtained in RILEM three-point notched beam tests. Its capability to model the fracture mode I is also assessed. The numerical strategy developed is described in the present work and the appropriateness of the model is evaluated simulating some beams tested experimentally.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BSAB/291/2002-POCTI. Fundo Social Europeu (FSE) -SFRH/BSAB/291/2002-POCTI

Studies on combining ability in tomato (Solanum lycopersicum L.)

ArticleThe present study was done seven elite tomato lines (Solamun lycopersicum L.) of determinate and indeterminate growth with good yield potential and good combining ability, using diallel fashion without reciprocals to produce 21 F1s. General combining ability (GCA) and Specific combining ability (SCA) analysis were conducted, with Diallel-SAS, assessing six yield and component traits. Results showed highly significant differences (p ≤ 0.01) among genotypes, as well as in GCA and SCA effects in all the characteristics that was assessed, with the exception of Days to First Cut. The results revealed that variance contribution to the yield attributed to the crossings had more non-additive effects (SCA) than additive effects (GCA). Furthermore, Line D4 had the greatest effect on yield in terms of GCA, as well in AFW (Average Fruit Weight), NFP (Number of Fruits per Plant) and PD (Polar Diameter) followed by D3 and K3. These lines can be used as donor parent in future tomato-breeding program. Hybrids K3×D4, R1×Y53, D3×IR13 and F3×Y53 had the highest level of SCA, with average yields of 93 t ha-1. These potential hybrids could be exploited at commercial level after critical testing

Implementación en FPGA de un sistema de medida de impedancia armónica de circuitos resonantes en serie basado en el algoritmo lock-in

En esta ponencia se presenta un sistema digital implementado en FPGA (field programmablegate array) cuya función es la medida en tiempo real de la impedancia del primer armónico deuna carga de una cocina de calentamiento por inducción. La etapa inversora de la cocinaimplementa la topología semipuente resonante serie de media frecuencia (25 kHz – 75 kHz)cuyo circuito de carga consiste en un condensador en serie con el sistema inductor‐recipiente(inductor planar acoplado con un recipiente). En una primera aproximación, la impedancia delcircuito puede modelarse como una red equivalente R‐L‐C, sin embargo, la impedanciaequivalente depende de múltiples factores tales como el material del recipiente, alineamientoentre el recipiente y el inductor, temperatura o frecuencia de trabajo. Por dicha razón, unacaracterización en tiempo real de la carga es deseable para realizar un correcto control de laetapa inversora. El sistema de identificación calcula la impedancia del primer armónico de lacarga aplicando el algoritmo lock‐in de fase dual a la corriente que atraviesa el inductor y a latensión de salida del inversor. Dicho algoritmo ha sido descrito en VHDL (very high speedintegrated circuit hadware description language) e implementado en una FPGA de Xilinx. Laprecisión del algoritmo ha sido verificada mediante simulación a través de una herramienta desimulación mixta (analógica‐digital). Finalmente, el sistema ha sido verificadoexperimentalmente

Genetic components for fodder yield and agronomic characters in maize lines

In maize hybrid development, it is essential to know the parent’s performance per se in different environments as well as the genetic base in populations in order to facilitate selection of superior lines. The objective of this work was to estimate the genetic variance and heritability while assessing agronomic behavior in 237 maize fodder lines featuring different inbred levels and origin in two different locations. Traits such as plant height, cob height, stem diameter, and fodder yield were taken. A combined variance analysis was carried out using this information. The variable mean squares showing significant differences were used to estimate the genetic variance components. Significant differences were observed (p ≤ 0.01) for the line variation source and location × line interaction in all assessed characteristics. The genetic parameter estimation provided information on the existing genetic variance and heritability among the population which is important for the progress of the selection process. Lines CLWN701, CLWN345, CML476, CML216, CLWQ232, and CML 528 measured 74.8, 72.2, 67.7, 65.8, 63.8 and 62.5 t ha-1 , respectively showed the highest yield potential for green fodder

Discovering planets with PLATO: Comparison of algorithms for stellar activity filtering

Context. To date, stellar activity is one of the main limitations in detecting small exoplanets via transit photometry. Since this activity is enhanced in young stars, traditional filtering algorithms may severely under-perform in detecting such exoplanets. Aims.This paper aims to compare the relative performances of four algorithms developed by independent research groups specifically for the filtering of activity in the light curves (LCs) of young active stars, prior to the search for planetary transit signals: Notch and LOCoR(N&L), Young Stars Detrending(YSD), K2 Systematics Correction(K2SC) and VARLET. We include in the comparison also the two best-performing algorithms implemented in Wotan, namely the Tukey's biweight and the Huber Spline. Methods. We performed a series of injection-retrieval tests of planetary transits of different types, from Jupiter down to Earth-sized planets, moving both on circular and eccentric orbits. The tests were carried out over 100 simulated LCs of both quiet and active solar-like stars that will be observed by the ESA space telescope PLATO. Results. We found that N&L is the best choice in many cases, since it misses the lowest number of transits. However, it under-performs if the planetary orbital period closely matches the stellar rotation period, especially in the case of small planets for which the biweight and VARLET algorithms work better. For LCs with a large number of data, the combined results of YSD and Huber Spline yield the highest recovery percentage. Filtering algorithms allow us to get a very precise estimate of the orbital period and the mid-transit time of the detected planets, while the planet-to-star radius is under-estimated most of the time, especially in the case of grazing transits or eccentric orbits. A refined filtering taking into account the presence of the planet is compulsory for a proper planetary characterization.Comment: 25 pages, accepted for publication by A&

K2-99: a subgiant hosting a transiting warm Jupiter in an eccentric orbit and a long-period companion

We report the discovery from K2 of a transiting planet in an 18.25-d, eccentric (0.19 ą 0.04) orbit around K2-99, an 11th magnitude subgiant in Virgo

Super-Earth of 8 M⊕ in a 2.2-day orbit around the K5V star K2-216

Context. Although thousands of exoplanets have been discovered to date, far fewer have been fully characterised, in particular super-Earths. The KESPRINT consortium identified K2-216 as a planetary candidate host star in the K2 space mission Campaign 8 field with a transiting super-Earth. The planet has recently been validated as well. Aims: Our aim was to confirm the detection and derive the main physical characteristics of K2-216 b, including the mass. Methods: We performed a series of follow-up observations: high-resolution imaging with the FastCam camera at the TCS and the Infrared Camera and Spectrograph at Subaru, and high-resolution spectroscopy with HARPS (La Silla), HARPS-N (TNG), and FIES (NOT). The stellar spectra were analyzed with the SpecMatch-Emp and SME codes to derive the fundamental stellar properties. We analyzed the K2 light curve with the pyaneti software. The radial velocity measurements were modelled with both a Gaussian process (GP) regression and the so-called floating chunk offset (FCO) technique to simultaneously model the planetary signal and correlated noise associated with stellar activity. Results: Imaging confirms that K2-216 is a single star. Our analysis discloses that the star is a moderately active K5V star of mass 0.70 ± 0.03 M⊙ and radius 0.72 ± 0.03 R⊙. Planet b is found to have a radius of 1.75-0.10+0.17 R⊕ and a 2.17-day orbit in agreement with previous results. We find consistent results for the planet mass from both models: Mp ≈ 7.4 ± 2.2 M⊕ from the GP regression and Mp ≈ 8.0 ± 1.6 M⊕ from the FCO technique, which implies that this planet is a super-Earth. The incident stellar flux is 2.48-48+220 F⊕. Conclusions: The planet parameters put planet b in the middle of, or just below, the gap of the radius distribution of small planets. The density is consistent with a rocky composition of primarily iron and magnesium silicate. In agreement with theoretical predictions, we find that the planet is a remnant core, stripped of its atmosphere, and is one of the largest planets found that has lost its atmosphere