We present ~47,000 periodic variables found during the analysis of 5.4 million variable star candidates within a 20,000 degsup 2 region covered by the Catalina Surveys Data Release-1 (CSDR1). ...Combining these variables with type ab RR Lyrae from our previous work, we produce an online catalog containing periods, amplitudes, and classifications for ~61,000 periodic variables. By cross-matching these variables with those from prior surveys, we find that >90% of the ~8000 known periodic variables in the survey region are recovered. Based on the examination of 31,000 contact binary light curves we find evidence for two subgroups exhibiting irregular light curves. One subgroup presents significant variations in mean brightness that are likely due to chromospheric activity. The other subgroup shows stable modulations over more than a thousand days and thereby provides evidence that the O'Connell effect is not due to stellar spots.
The agaves are plants of cultural importance which have been used by humans for about 10,000 years and about 40 specific uses. The most culturally and economically important of those uses are for the ...production of fermented (pulque) and distilled beverages (mescal). Pulque continues to be produced in nearly all of Mexico, and the agaves used for this purpose have shown domestication syndrome. We carry out an ethnobotanical, morphological, and genetic analysis of the traditional varieties of pulque agave used in the production of aguamiel (agave sap) and pulque in the state of Hidalgo. We did semi-structured interviews, free listings, and tours with 11 agave managers. We analyzed morphology and studied genetic diversity and structure using nuclear microsatellites. We found wild-collected, tolerated, transplanted, and cultivated varieties of agave. This comprised 19 traditional varieties of pulque agave, 12 of them in production during the study, which corresponded to the species Agave americana, A. salmiana y A. mapisaga and five intraspecific entities. The varieties were grouped morphologically according to a management gradient; the wild-collected varieties were the smallest, with more lateral teeth and a larger terminal spine. The cultivated varieties clearly exhibited domestication syndrome, with larger plants and smaller dentition. The expected heterozygosity (He) of the varieties ranged from 0.204 to 0.721. Bayesian clustering suggested the existence of three genetic groups, both at the level of traditional varieties of pulque agaves and for management categories, a result that matches multivariate clustering. Pulque producers in the studied localities maintain high agrobiodiversity. The cultivated varieties exhibit domestication syndrome, as has been reported for other species of the genus with the same selection purposes. Our results support the hypothesis of a decrease in genetic diversity in crops compared to wild-growing agaves, which seems to be due to vegetative propagation, among other factors.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Context. The current distribution of planet mass vs. incident stellar X-ray flux supports the idea that photoevaporation of the atmosphere may take place in close-in planets. Integrated effects have ...to be accounted for. A proper calculation of the mass loss rate through photoevaporation requires the estimation of the total irradiation from the whole XUV (X-rays and extreme ultraviolet, EUV) range. Aims. The purpose of this paper is to extend the analysis of the photoevaporation in planetary atmospheres from the accessible X-rays to the mostly unobserved EUV range by using the coronal models of stars to calculate the EUV contribution to the stellar spectra. The mass evolution of planets can be traced assuming that thermal losses dominate the mass loss of their atmospheres. Methods. We determine coronal models for 82 stars with exoplanets that have X-ray observations available. Then a synthetic spectrum is produced for the whole XUV range (~1−912 Å). The determination of the EUV stellar flux, calibrated with real EUV data, allows us to calculate the accumulated effects of the XUV irradiation on the planet atmosphere with time, as well as the mass evolution for planets with known density. Results. We calibrate for the first time a relation of the EUV luminosity with stellar age valid for late-type stars. In a sample of 109 exoplanets, few planets with masses larger than ~1.5 MJ receive high XUV flux, suggesting that intense photoevaporation takes place in a short period of time, as previously found in X-rays. The scenario is also consistent with the observed distribution of planet masses with density. The accumulated effects of photoevaporation over time indicate that HD 209458b may have lost 0.2 MJ since an age of 20 Myr. Conclusions. Coronal radiation produces rapid photoevaporation of the atmospheres of planets close to young late-type stars. More complex models are needed to explain the observations fully. Spectral energy distributions in the XUV range are made available for stars in the sample through the Virtual Observatory for the use in future planet atmospheric models.
Context. HBC 722 (V2493 Cyg) is a young eruptive star in outburst since 2010. Spectroscopic evidence suggests that the source is an FU Orionis-type object, with an atypically low outburst luminosity. ...Aims. Because it was well characterized in the pre-outburst phase, HBC 722 is one of the few FUors from which we can learn about the physical changes and processes associated with the eruption, including the role of the circumstellar environment. Methods. We monitored the source in the BVRIJHKS bands from the ground and at 3.6 and 4.5 μm from space with the Spitzer Space Telescope. We analyzed the light curves and studied the evolving spectral energy distribution by fitting a series of steady accretion disk models at many epochs covering the outburst. We also analyzed the spectral properties of the source based on our new optical and infrared spectra, comparing our line inventory with those published in the literature for other epochs. We also mapped HBC 722 and its surroundings at millimeter wavelengths. Results. From the light-curve analysis we conclude that the first peak of the outburst in 2010 September was mainly due to an abrupt increase in the accretion rate in the innermost part of the system. This was followed after a few months by a long-term process, when the brightening of the source was mainly due to a gradual increase in the accretion rate and the emitting area. Our new observations show that the source is currently in a constant plateau phase. We found that the optical spectrum was similar in the first peak and following periods, but around the peak the continuum was bluer and the Hα profile changed significantly between 2012 and 2013. The source was not detected in the millimeter continuum, but we discovered a flattened molecular gas structure with a diameter of 1700 au and mass of 0.3 M⊙ centered on HBC 722. Conclusions. While the first brightness peak might be interpreted as a rapid fall of piled-up material from the inner disk onto the star, the later monotonic flux rise suggests the outward expansion of a hot component according to a previously described theory. Our study of HBC 722 demonstrates that accretion-related outbursts can occur in young stellar objects even with very low-mass disks in the late Class II phase.
Context. The Arjuna asteroid belt is loosely defined as a diverse group of small asteroids that follow dynamically cold, Earth-like orbits. Most of them are not actively engaged in resonant, ...co-orbital behavior with Earth. Some of them experience temporary but recurrent horseshoe episodes. Objects in horseshoe paths tend to approach Earth at a low velocity, leading to captures as Earth’s temporary satellites or mini-moons. Four such objects have already been identified: 1991 VG, 2006 RH120, 2020 CD3, and 2022 NX1. Here, we focus on 2023 FY3, a recent finding, the trajectory of which might have a co-orbital status and perhaps lead to temporary captures. Aims. We want to determine the physical properties of 2023 FY3 and explore its dynamical evolution. Methods. We carried out an observational study of 2023 FY3 using the OSIRIS camera spectrograph at the 10.4 m Gran Telescopio Canarias, to derive its spectral class, and time-series photometry obtained with QHY411M cameras and two units of the Two-meter Twin Telescope to investigate its rotational state. N-body simulations were also performed to examine its possible resonant behavior. Results. The visible reflectance spectrum of 2023 FY3 is consistent with that of an S-type asteroid; its light curve gives a rotation period of 9.3±0.6 min, with an amplitude of 0.48±0.13 mag. We confirm that 2023 FY3 roams the edge of Earth’s co-orbital space. Conclusions. Arjuna 2023 FY3, an S-type asteroid and fast rotator, currently exhibits horseshoe-like resonant behavior and in the past experienced mini-moon engagements of the temporarily captured flyby type that may repeat in the future. The spectral type result further confirms that mini-moons are a diverse population in terms of surface composition.
Here, a measurement with high statistics of the differential energy spectrum of light elements in cosmic rays, in particular, of primary H plus He nuclei, is reported. The spectrum is presented in ...the energy range from 6 to 158 TeV per nucleus. Data was collected with the High Altitude Water Cherenkov (HAWC) Observatory between June 2015 and June 2019. The analysis was based on a Bayesian unfolding procedure, which was applied on a subsample of vertical HAWC data that was enriched to 82% of events induced by light nuclei. To achieve the mass separation, a cut on the lateral age of air shower data was set guided by predictions of CORSIKA/QGSJET-II-04 simulations. The measured spectrum is consistent with a broken power-law spectrum and shows a kneelike feature at around E = 24.0$^{+3.6}_{-3.1}$ TeV , with a spectral index γ = -2.51 ± 0.02 before the break and with γ = -2.83 ± 0.02 above it. The feature has a statistical significance of 4.1σ. Within systematic uncertainties, the significance of the spectral break is 0.8σ.
Abstract Background Nowadays, contrast-induced nephropathy (CIN) is the third cause of acquired acute renal impairment in hospital. CIN is related to increased in-hospital morbidity, mortality, costs ...of medical care, and long admissions. Because of this, we hypothesized it would be useful to determine the risk of CIN with scores such as the Mehran score. The aim of this study was to validate the Mehran score in a contemporary cohort of Spanish patients with acute coronary syndrome (ACS). Methods We assessed the calibration and discriminatory capacity of Mehran score to predict CIN in a cohort of 1520 patients with a definitive diagnosis of ACS and who underwent coronary angiography between March 2008 and June 2012. We excluded patients on chronic dialysis and those without data of contrast volume. The calibration of the model was assessed with the Hosmer-Lemeshow goodness-of-fit test and discriminatory capacity was assessed by C-statistic, which is equivalent to the area under the receiver-operating characteristic curve. Results From the total group, 118 patients (7.8%) developed CIN. They were older, with higher rates of diabetes (DM) and hypertension and worse renal function and anemia ( p < 0.001). The odds ratios for different score components in Mehran's population versus our study were similar except for DM, hypotension, and intra-aortic balloon pump (1.6%, 2.68%, 2.55% vs 0.9%, 1.89%, and 2.86%, respectively). Calibration and discriminatory capacity of Mehran score were excellent with a Hosmer-Lemeshow p = 0.7, C-statistic value >0.8. Conclusions Mehran risk score has been validated in our study as a good score for predicting CIN in patients with ACS who underwent coronary angiography. According to this, we support its use in patients hospitalized for ACS in order to identify the ones at risk, and to optimize CIN prophylactic therapy prior to and after catheterization.
V582 Aur is an FU Ori-type young eruptive star in outburst since ∼1985. The eruption is currently in a relatively constant plateau phase, with photometric and spectroscopic variability superimposed. ...Here we will characterize the progenitor of the outbursting object, explore its environment, and analyze the temporal evolution of the eruption. We are particularly interested in the physical origin of the two deep photometric dips, one that occurred in 2012 and one that is ongoing since 2016. We collected archival photographic plates and carried out new optical, infrared, and millimeter-wave photometric and spectroscopic observations between 2010 and 2018, with a high sampling rate during the current minimum. Besides analyzing the color changes during fading, we compiled multiepoch spectral energy distributions and fitted them with a simple accretion disk model. Based on pre-outburst data and a millimeter continuum measurement, we suggest that the progenitor of the V582 Aur outburst is a low-mass T Tauri star with average properties. The mass of an unresolved circumstellar structure, probably a disk, is 0.04 M . The optical and near-infrared spectra demonstrate the presence of hydrogen and metallic lines, show the CO band head in absorption, and exhibit a variable H profile. The color variations strongly indicate that both the ∼1 yr long brightness dip in 2012 and the current minimum since 2016 are caused by increased extinction along the line of sight. According to our accretion disk models, the reddening changed from AV = 4.5 to 12.5 mag, while the accretion rate remained practically constant. Similarly to the models of the UXor phenomenon of intermediate- and low-mass young stars, orbiting disk structures could be responsible for the eclipses.
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