•BjV decreases CD1d, CD83, and CD86 expression on BMDCs.•BjV did not promote the release of IL-1β, IL-6, or TNF-α.•BjV affects the maturation of DCs.
This study was designed to characterize mice bone ...marrow (BM) and bone marrow-derived dendritic cells (BMDC) and to compare the surface markers expression and inflammatory cytokine liberation in response to LPS and Bothrops jararacussu venom (BjV) stimulation. Typical morphology was observed in BM and BMDCs from the 4th up to the 8th day of culture using recombinant mouse GM-CSF and IL-4. A high basal level of MHC-II, CD1d, CD83, CD11c, CD80, and low CD86 was expressed by BM cells. After stimulation with GM-CSF/IL-4 for BMDCs differentiation, the BM cells differentiated into BMDCs presented MHC-II, CD1d, CD83, CD11c, CD86, and CD80 expression on the 4th – 8th day accompanied with high levels of TNF-α liberated. The difference between the surface markers' expression was observed in this time course in which CD1d, CD11c, and CD80 remained in high levels of expression, while MHC-II and CD83 showed moderate expression during the differentiation period. Also, cytokines liberation was monitored over the period of the BMDCs culture, and on the 6th day, low levels of IL-6 and IL-1β were found, while high levels of TNF-α on the 4th and 8th days, both of which contributed to the maturity of the BMDCs. Maturation of DCs with LPS showed significant upregulation of surface markers (MHC-II, CD1d, CD83, CD86, CD80) and pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) liberation. On the other hand, BjV induced a decrease in CD1d, CD11c, CD83, and CD86 expression in mature BMDCs which was not observed when LPS was used to stimulate BMDCs which probably induces impairment in T-cell activation.
ABSTRACT
We present the identification and photometric analysis of 30 new low mass ratio (LMR) totally eclipsing contact binaries found in Catalina Sky Survey data. The LMR candidates are identified ...using Fourier coefficients and visual inspection. We perform a detailed scan in the parameter plane of mass ratio (q) versus inclination (i) using phoebe
-0.31 scripter to derive the best (q, i) pair for the initial models. The relative physical parameters are determined from the final model of each system. A Monte Carlo approach was adopted to derive the parameter errors. The resulting parameters confirm the identification. The approximate absolute physical parameters of the systems are estimated based on the light-curve solutions and Gaia Early Data Release 3 distances. 12 out of 30 new systems have fill-out factors $f\gt 50{{\ \rm per\ cent}}$ and q ≤ 0.25 (deep contact LMR systems), and eight of them, to within errors, are extreme LMR deep systems with q ≤ 0.1. We discuss the evolutionary status of the 30 LMR systems in comparison with the most updated catalogue of LMR systems from the literature. The scenario of the LMR systems as pre-merger candidates forming fast rotating stars is investigated for all systems, new and old, based both on Hut’s stability criteria and critical instability mass ratio (qinst) relation. CSS$\_$J075848.2+125656, with q/qinst = 1.23 ± 0.23, and CSS$\_$J093010.1−021624, with q/qinst = 1.25 ± 0.23, can be considered as merger candidates.
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Abstract
We present a multiband photometric analysis of CRTS J163819.6+03485, the first low-mass-ratio contact binary system with a period of 0.2053321 day under the contact binary period limit. The ...unprecedented combination of mass ratio and period makes this system unique for eclipsing binary (EB) research. Using new multiband photometric observations, we explored the parameter space of this unique total EB system through a detailed scan in the mass ratio–inclination plane and using the
pikaia
genetic algorithm optimizer. The best set of relative physical parameters and corresponding uncertainties was adopted through Markov Chain Monte Carlo sampling of the parameter space. The resulting mass ratio of the system is
q
= 0.16 ± 0.01. The absolute parameters were derived by adopting an empirical mass–luminosity relation. Period changes are also investigated by using new observations and archival photometric light curves from massive astronomical surveys, which revealed in a preliminary solution the presence of a possible low-mass tertiary companion. The origin and evolutionary status of the system are investigated through the detached binary formation scenario.
Abstract
We present the photometric analysis of three ultra-short-period total eclipsing binaries in contact configuration, CRTS_J172718.0+431624, OGLE-BLG-ECL-000104, and OGLE-BLG-ECL-000012, mined ...from massive astronomical surveys. Using the available archival light curves (LCs) from Vista Variables in the Vía Láctea (VVV), Optical Gravitational Lensing Experiment (OGLE), Zwicky Transient Facility, and Catalina Sky Survey in different passbands and new multiband photometric observations with the 2.3 m Aristarchos telescope at Helmos Observatory, their relative physical parameters were derived. We explored the parameter space by using the PIKAIA genetic algorithm optimizer. The best photometric solution and error budget estimation were adopted for each system through Markov Chain Monte Carlo sampling of the global optimum. The approximate absolute parameters were derived for each contact system adopting an empirical mass–luminosity relation. All three systems have a mass ratio lower than 0.5. The exchange between the primary and secondary depths of CRTS_J172718.0+431624 during 2016–2022 may be due to spot activity. In addition, we present a detailed analysis of the first well-characterized shortest-period contact eclipsing binary with total eclipses known so far (OGLE-BLG-ECL-000104). Thanks to VVV and OGLE LCs, new distances were derived for OGLE-BLG-ECL-000104 and OGLE-BLG-ECL-000012 using empirical period–luminosity relations. The origin and evolutionary status of all three ultra-short-period contact binaries are thoroughly discussed in the context of the detached binary formation channel.
Asian soybean rust (ASR), caused by the fungus
Phakopsora pachyrhizi
, is the main disease affecting soybean in Brazil. This study aimed at investigating and mapping the resistance of the PI 594756 ...to
P. pachyrhizi
, by using Bulked Segregant Analysis (BSA). The PI 594756 and the susceptible PI 594891 were crossed and the resulting
F
2
and
F
2:3
populations (208 and 1770 plants, respectively) were tested against ASR. Also, these PIs and differential varieties were tested against a panel of monosporic isolates. Plants presenting tan lesions were classified as susceptible (
S
) while plants presenting reddish-brown (RB) lesions were classified as resistant. DNA bulks were genotyped with Infinium BeadChips and the genomic region identified was further analyzed in the
F
2
individuals with target GBS (tGBS). PI 594,56 presented a unique resistance profile compared to the differential varieties. The resistance was monogenic dominant; however, it was classified as incompletely dominant when quantitatively studied. Genetic and QTL mapping placed the PI 594756 gene between the genomic region located at 55,863,741 and 56,123,516 bp of chromosome 18. This position is slightly upstream mapping positions of
Rpp1
(PI 200492) and
Rpp1-b
(PI 594538A). Finally, we performed a haplotype analysis in a whole genomic sequencing-SNP database composed of Brazilian historical germplasm and sources of
Rpp
genes. We found SNPs that successfully differentiated the new PI 594756 allele from
Rpp1
and
Rpp1-b
sources. The haplotype identified can be used as a tool for marker-assisted selection (MAS).
Pulsation in TESS Objects of Interest Gomes, R. L.; Martins, B. L. Canto; Fontinele, D. O. ...
The Astrophysical journal,
01/2024, Letnik:
961, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Abstract
We report the discovery of three Transiting Exoplanet Survey Satellite Objects of Interest (TOI) with signatures of pulsation, observed in more than one sector. Our main goal is to explore ...how large is the variety of classical pulsators such as
δ
Sct,
γ
Dor, RR Lyrae and Cepheid among TOI pulsators. The analysis reveals two stars with signatures of
δ
Sct and one of
γ
Dor, out of a sample of 3901 TOIs with available light curves (LCs). To date, there is a very scarce number of known pulsating stars hosting planets. The present finding also emerges as an exciting laboratory for studying different astrophysical phenomena, including the effects of star–planet interaction on pulsation and timing detection of planetary companions. We have also identified 16 TOI stars with periodicities and LCs morphology compatible with different classical pulsating classes, but for most of them, the dominant frequency signals originate from contaminating sources.
In recent years, several close post-common-envelope eclipsing binaries have been found to show cyclic eclipse timing variations (ETVs). This effect is usually interpreted either as the gravitational ...interaction among circumbinary bodies and the host binary-known as the light travel time (LTT) effect-or as the quadrupole moment variations in one magnetic active component-known as the Applegate mechanism. In this study, we present an analysis of the ETV and the magnetic cycle of the close binary KIC 10544976. This system is composed of a white dwarf and a red dwarf in a short orbital period (0.35 days) and was monitored by ground-based telescopes between 2005 and 2017 and by the Kepler satellite between 2009 and 2013. Using the Kepler data, we derived the magnetic cycle of the red dwarf by two ways: the rate and energy of flares and the variability due to spots. Both methods resulted in a cycle of ∼600 days, which is in agreement with magnetic cycles measured for single low-mass stars. The orbital period of KIC 10544976 shows only one long-term variation which can be fitted by an LTT effect with period of ∼16.8 yr. Hence, one possible explanation for the ETVs is the presence of a circumbinary body with a minimal mass of ∼13.4 MJup. In the particular scenario of coplanarity between the external body and the inner binary, the third body mass is also ∼13.4 MJup. In this case, the circumbinary planet must either have survived the evolution of the host binary or have been formed as a consequence of its evolution.
The present study reports the discovery of Sun-like stars, namely main-sequence stars with T sub( eff), log g and rotation periods P sub( rot) similar to solar values, presenting evidence of surface ...differential rotation (DR). An autocorrelation of the time series was used to select stars presenting photometric signal stability from a sample of 881 stars with light curves collected by the Kepler space-borne telescope, in which we have identified 17 stars with stable signals. A simple two-spot model together with a Bayesian information criterion were applied to these stars in the search for indications of DR; in addition, for all 17 stars, it was possible to compute the spot rotation period P, the mean values of the individual spot rotation periods and their respective colatitudes, and the relative amplitude of the DR.
ABSTRACT We analyzed the host stars of the present sample of confirmed planets detected by Kepler and Kepler Objects of Interest to compute new photometric rotation periods and to study the behavior ...of their angular momentum. Lomb-Scargle periodograms and wavelet maps were computed for 3807 stars. For 540 of these stars, we were able to detect rotational modulation of the light curves at a significance level of greater than 99%. For 63 of these 540 stars, no rotation measurements were previously available in the literature. According to the published masses and evolutionary tracks of the stars in this sample, the sample is composed of M- to F-type stars (with masses of 0.48-1.53 M ) with rotation periods that span a range of 2-89 days. These periods exhibit an excellent agreement with those previously reported (for the stars for which such values are available), and the observed rotational period distribution strongly agrees with theoretical predictions. Furthermore, for the 540 sources considered here, the stellar angular momentum provides an important test of Kraft's relation based on the photometric rotation periods. Finally, this study directly contributes in a direct approach to our understanding of how angular momentum is distributed between the host star and its (detected) planetary system; the role of angular momentum exchange in such systems is an unavoidable piece of the stellar rotation puzzle.
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