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A study on the photosphere and disc of the Be star β Psc is presented. We recover almost 40 yr of high-resolution spectroscopic observations and additional data gathered from the BeSS data base. We evaluate the photospheric parameters from the spectral energy distribution (SED) and fittings of state-of-the-art non-LTE model atmospheres to observed helium, carbon, silicon, and magnesium line profiles. Our models include the stellar geometric deformation as well as the co-latitude dependence of temperature and gravity, aiming to derive the effects of rotation on the stellar parameters. We estimate the circumstellar disc parameters from the fitting of models assuming different disc properties, namely its radius and gas density profile. The disc inclination angle i is constrained from the fittings of He  i 4471 Å, Mg  ii 4481 Å, C  ii 4267 Å,  and Si  ii 4128, 4132 Å  lines with gravity darkened models. Our findings, based on model fittings, suggest that during the last 40 yr, the disc radius changed within the interval 5.5 ≤ R d ≤ 7.8 |$R/R_{*}\,$|⁠ , the disc base gas density within 5 × 10−13 ≤ ρ ≤ 1 × 10−12 g cm−3, while the radial power-law density index m assumed values between 2.0 and 2.3. These results are in agreement with recent works dealing with spectroscopic and interferometric measurements of this object. [ABSTRACT FROM AUTHOR]

The λ Boo stars are chemically peculiar A-type stars whose abundance anomalies are associated with the accretion of metal-poor material. We searched for λ Boo stars in the Southern hemisphere in a targeted spectroscopic survey of metal-weak and emission-line stars. Obtaining spectra for 308 stars and classifying them on the MK system, we found or co-discovered 24 new λ Boo stars. We also revised the classifications of 11 known λ Boo stars, one of which turned out to be a chemically normal rapid rotator. We show that stars previously classified in the literature as blue horizontal branch stars or emission-line A stars have a high probability of being λ Boo stars, although this conclusion is based on small-number statistics. Using WISE infrared fluxes, we searched our targets for infrared excesses that might be attributable to protoplanetary or debris discs as the source of the accreted material. Of the 34 λ Boo stars in our sample, 21 at various main-sequence ages have infrared excesses, confirming that not all λ Boo stars are young. [ABSTRACT FROM AUTHOR]

OBJECTIVES: The present study was designed to explore the roles of inflammatory cytokines interleukin-1β (IL-1β) and Tumor growth factor-β (TGF-β) in the diagnosis and treatment of neonate bilirubin encephalopathy (BE). METHODS: A total of 128 BE neonates and 128 normal neonates were included. The serum samples of the BE children and controls were collected, and the levels of IL-1β and TGF-β were examined. Moreover, the correlation between the level of bilirubin and serum expression of IL-1β or TGF-β in BE patients was analyzed. Finally, receiver operating characteristic (ROC) curves were generated to determine the diagnostic value of the cytokines. RESULTS: IL-1β and TGF-β levels were higher in the serum of BE patients than those in non-BE patients, and the expression of either IL-1β or TGF-β showed a strong positive correlation with the serum expression of bilirubin in BE patients. Moreover, the results of ROC analysis showed that either IL-1β or TGF-β could distinguish BE patients from healthy controls. CONCLUSION: IL-1β and TGF-β levels were upregulated in BE and might function as potential biomarkers or therapeutic targets for BE patients.

We present the results of study of the Galactic candidate luminous blue variable Wray 15-906, revealed via detection of its infrared circumstellar shell (of ≈2 pc in diameter) with the Wide-field Infrared Survey Explorer and the Herschel Space Observatory. Using the stellar atmosphere code cmfgen and the Gaia parallax, we found that Wray 15-906 is a relatively low-luminosity, |$\log (L/\rm \, L_\odot)\approx 5.4$|⁠ , star of temperature of 25 ± 2 kK, with a mass-loss rate of |${\approx}3\times 10^{-5} \, \rm \, M_\odot \, {\rm yr}^{-1}$|⁠ , a wind velocity of |$280\pm 50 \, {\rm \, km\, s^{-1}}$|⁠ , and a surface helium abundance of 65 ± 2 per cent (by mass). In the framework of single-star evolution, the obtained results suggest that Wray 15-906 is a post-red supergiant star with initial mass of |${\approx}25 \, \rm \, M_\odot$| and that before exploding as a supernova it could transform for a short time into a WN11h star. Our spectroscopic monitoring with the Southern African Large Telescope does not reveal significant changes in the spectrum of Wray 15-906 during the last 8 yr, while the V -band light curve of this star over years 1999–2019 shows quasi-periodic variability with a period of ≈1700 d and an amplitude of ≈0.2 mag. We estimated the mass of the shell to be |$2.9\pm 0.5 \, \rm \, M_\odot$| assuming the gas-to-dust mass ratio of 200. The presence of such a shell indicates that Wray 15-906 has suffered substantial mass-loss in the recent past. We found that the open star cluster C1128−631 could be the birth place of Wray 15-906 provided that this star is a rejuvenated product of binary evolution (a blue straggler). [ABSTRACT FROM AUTHOR]

Be X-ray binaries (BeXRBs) consist of rapidly rotating Be stars with neutron star (NS) companions accreting from the circumstellar emission disc. We compare the observed population of BeXRBs in the Small Magellanic Cloud (SMC) with simulated populations of BeXRB-like systems produced with the compas population synthesis code. We focus on the apparently higher minimal mass of Be stars in BeXRBs than in the Be population at large. Assuming that BeXRBs experienced only dynamically stable mass transfer, their mass distribution suggests that at least |$\sim 30{{\ \rm per\ cent}}$| of the mass donated by the progenitor of the NS is typically accreted by the B-star companion. We expect these results to affect predictions for the population of double compact object mergers. A convolution of the simulated BeXRB population with the star formation history of the SMC shows that the excess of BeXRBs is most likely explained by this galaxy's burst of star formation ∼20–40 Myr ago. [ABSTRACT FROM AUTHOR]

γ Cas stars constitute a subgroup of Be stars showing unusually hard and bright X-ray emission. In search for additional peculiarities, we analysed the TESS light curves of 15 γ Cas analogues. Their periodograms display broad frequency groups and/or narrow isolated peaks, often superimposed over red noise. The detected signals appear at low frequencies, with few cases of significant signals beyond 5 d−1 (and all of them are faint). The signal amplitudes, and sometimes the frequency content, change with time, even in the absence of outburst events. On the basis of their optical photometric variability, γ Cas stars reveal no distinctive behaviour and thus appear similar to Be stars in general. [ABSTRACT FROM AUTHOR]

In this note I present the unified theory of copular sentences proposed by Andrea Moro, who maintains that the verb to be is nothing more than a support for verbal inflection, regardless of the grammatical and semantic peculiarities of the ascriptive, equative, and existential sentences in which it appears. First, I contextualize Moro's proposal. Then, I explain how Moro clarifies a syntactic anomaly that seems to corroborate the alleged polysemy of the verb to be. Lastly, I comment on some omissions of philosophical relevance in the history of the verb to be told by Moro. [ABSTRACT FROM AUTHOR]

We report on the discovery of Swift J004516.6–734703, a Be/X-ray binary system by the Swift SMC Survey, S-CUBED. Swift J004516.6–734703, or SXP 146.6, was found to be exhibiting a bright (∼1037 erg s−1) X-ray outburst on 2020 June 18. The historical UV and IR light-curves from OGLE and Swift /UVOT showed that after a long period of steady brightness, it experienced a significant brightening beginning around 2019 March. This IR/UV rise is likely the signature of the formation of a circumstellar disc, confirmed by the presence of strong an H α line in SALT spectroscopy, that was not previously present. Periodicity analysis of the OGLE data reveals a plausible 426 d binary period, and in X-ray a pulsation period of 146.6 s is detected. The onset of X-ray emission from Swift J004516.6–734703 is likely the signature of a Type-I outburst from the first periastron passage of the neutron star companion through the newly formed circumstellar disc. We note that the formation of the circumstellar disc began at the predicted time of the previous periastron passage, suggesting its formation was spurred by tidal interaction with the neutron star. [ABSTRACT FROM AUTHOR]

We use a smoothed particle hydrodynamics (SPH) code to examine the effects of a binary companion on a Be star disc for a range of disc viscosities and misalignment angles, i.e. the angle between the orbital plane and the primary star's spin axis. The density structures in the disc due to the tidal interaction with the binary companion are investigated. Expanding on our previous work, the shape and density structure of density enhancements due to the binary companion are analysed and the changes in observed interferometric features due to these orbiting enhancements are also predicted. We find that larger misalignment angles and viscosity values result in more tightly wound spiral arms with densities that fall-off more slowly with radial distance from the central star. We show that the orbital phase has very little effect on the structure of the spiral density enhancements. We demonstrate that these spiral features can be detected with an interferometer in H α and K- band emission. We also show that the spiral features affect the axis ratios determined by interferometry depending on the orientation of these features and the observer. For example, our simulations show that the axis ratios can vary by 20 per cent for our co-planar binary disc system depending on the location of the disc density enhancements. [ABSTRACT FROM AUTHOR]

The Be X-ray binary GRO J2058+42 recently went through a Type-II outburst during 2019 March–April lasting for about 50 d. This outburst was detected with the operating all sky X-ray monitors like the Fermi -GBM, Swift -BAT, and MAXI -GSC. Two Nuclear Spectroscopic Telescope Array (NuSTAR) observations were also made, one during the rise and other during the decay of the outburst. It gave us the unique opportunity to analyse the broad-band characteristics of the pulsar for the first time and accretion torque characteristics of the pulsar over a range of X-ray luminosity. The pulse profiles are strongly energy-dependent, with at least four different pulse components at low energy (< 20 keV), which evolves to a single-peaked profile at high energy (> 30 keV). In each of the narrow energy bands, the pulse profiles are nearly identical in the two NuSTAR observations. The spectra from both the observations are fitted well to a power-law with a Fermi–Dirac-type high-energy cutoff. We ruled out presence of a cyclotron line in the pulse phase averaged X-ray spectrum in the NuSTAR band with an optical depth greater than 0.15. An iron emission line is detected in both the NuSTAR spectra with an equivalent width of about 125 eV. We looked at the dependence of the spin-up rate on the luminosity and estimated the magnetic field strength from that, which came out to be much higher compared to other known BeXRB pulsars. Lastly, we discussed the inadequacy of the torque–luminosity relation for determination of magnetic field strength of neutron stars. [ABSTRACT FROM AUTHOR]

PSR B1259-63 is a gamma-ray binary system hosting a radio pulsar orbiting around an O9.5Ve star, LS 2883, with a period of ∼3.4 yr. The interaction of the pulsar wind with the LS 2883 outflow leads to unpulsed broad-band emission in the radio, X-rays, GeV, and TeV domains. While the radio, X-ray, and TeV light curves show rather similar behaviour, the GeV light curve appears very different with a huge outburst about a month after a periastron. The energy release during this outburst seems to significantly exceed the spin-down luminosity of the pulsar and both the GeV light curve and the energy release vary from one orbit to the next. In this paper, we present for the first time the results of optical observations of the system in 2017, and also reanalyse the available X-ray and GeV data. We present a new model in which the GeV data are explained as a combination of the bremsstrahlung and inverse Compton emission from the unshocked and weakly shocked electrons of the pulsar wind. The X-ray and TeV emission is produced by synchrotron and inverse Compton emission of energetic electrons accelerated on a strong shock arising due to stellar/pulsar winds collision. The brightness of the GeV flare is explained in our model as a beaming effect of the energy released in a cone oriented, during the time of the flare, in the direction of the observer. [ABSTRACT FROM AUTHOR]

We study five luminous blue variable (LBV) candidates in the Andromeda galaxy and one more (MN112) in the Milky Way. We obtain the same-epoch near-infrared (NIR) and optical spectra on the 3.5-m telescope at the Apache Point Observatory and on the 6-m telescope of the SAO RAS. The candidates show typical LBV features in their spectra: broad and strong hydrogen lines, He  i , Fe  ii , and [Fe  ii ] lines. We estimate the temperatures, reddening, radii and luminosities of the stars using their spectral energy distributions. Bolometric luminosities of the candidates are similar to those of known LBV stars in the Andromeda galaxy. One candidate, J004341.84+411112.0, demonstrates photometric variability (about 0.27 mag in the V band), which allows us to classify it as an LBV. The star J004415.04+420156.2 shows characteristics typical of B[e] supergiants. The star J004411.36+413257.2 is classified as a Fe  ii star. We confirm that the stars J004621.08+421308.2 and J004507.65+413740.8 are warm hypergiants. We obtain for the first time the NIR spectrum of the Galactic LBV candidate MN112. We use both optical and NIR spectra of MN112 for comparison with similar stars in M31 and notice identical spectra and the same temperature in J004341.84+411112.0. This allows us to confirm that MN112 is an LBV, which should show its brightness variability in longer time span observations. [ABSTRACT FROM AUTHOR]

PSR J2032+4127 is only the second known gamma-ray binary where it is confirmed that a young radio pulsar is in orbit around a Be-star. The interaction of the pulsar wind with the mass outflow from the companion leads to broad-band emission from radio up to TeV energies. In this paper we present results of optical monitoring of the 2017 periastron passage with the Nordic Optical Telescope. These observations are complemented by X-ray (Swift /XRT, NuSTAR) and GeV (Fermi /LAT) monitoring. Joint analysis of the evolution of the parameters of the H α line and the broad-band (X-ray to TeV) spectral shape allows us to propose a model linking the observed emission to the interaction of the pulsar and Be-star winds under the assumption of the inclined disc geometry. Our model allows the observed flux and spectral evolution of the system to be explained in a self-consistent way. [ABSTRACT FROM AUTHOR]

RX J0209.6–7427 is an X-ray source in the Magellanic Bridge that was first detected in 1993, but not seen again till 2019. It has been identified as a member of the Be/X-ray binary class, a category of objects that are well established as bright, often-unpredictable transients. Such systems are rarely known in the Bridge, possibly because they lie outside the area most commonly studied by X-ray telescopes. Whatever be the reason for the sparse number of such systems in the Bridge, they can provide useful tools for trying to understand the result of the tidal dynamics of the two Magellanic Clouds. In this paper, the nature of the object is explored with the help of new data obtained during the latest outburst. In particular, the first optical spectrum of the counterpart is presented to help classify the star, plus measurements of the Balmer emission lines over several years are used to investigate changes in the size and structure of the circumstellar disc. [ABSTRACT FROM AUTHOR]

We investigate the short-term optical variability of two γ Cas analogues,  πAqr and BZ Cru, thanks to intensive ground-based spectroscopic and space-borne photometric monitorings. For both stars, low-amplitude (mmag) coherent photometric variability is detected. The associated signals display long-term amplitude variations, as in other Be stars. However, these signals appear at high frequencies, especially in  πAqr, indicating p modes with a high degree l , a quite unusual feature amongst Be stars. While BZ Cru presents only low-level spectral variability, without clear periodicity, this is not the case of πAqr. In this star, the dominant photometric frequencies, near ∼12 d−1, are confirmed spectroscopically in separate monitorings taken during very different disc activity levels; the spectroscopic analysis suggests a probable tesseral nature for the mode. [ABSTRACT FROM AUTHOR]

The Galactic emission-line object MWC 349A is one of the brightest radio stars in the sky. The central object is embedded in an almost edge-on oriented Keplerian rotating thick disc that seems to drive a rotating bipolar wind. The dense disc is also the site of hot molecular emission such as the CO bands with its prominent band heads in the near-infrared spectral range. Despite numerous studies, the nature of MWC 349A is still controversial with classifications ranging from a pre-main sequence object to an evolved supergiant. We collected new high-resolution near-infrared spectra in the K and L bands using the GNIRS spectrograph at Gemini-North to study the molecular disc of MWC 349A, and in particular to search for other molecular species such as SiO and the isotope 13CO. The amount of 13CO, obtained from the 12CO/13CO ratio, is recognized as an excellent tool to discriminate between pre-main-sequence and evolved massive stars. We find no signatures of SiO band emission, but detect CO band emission with considerably lower intensity and CO gas temperature compared to previous observations. Moreover, from detailed modelling of the emission spectrum, we derive an isotope ratio of 12CO/13CO = 4 ± 1. Based on this significant enrichment of the circumstellar environment in 13CO, we conclude that MWC 349A belongs to the group of B[e] supergiants, and we discuss possible reasons for the drop in CO intensity. [ABSTRACT FROM AUTHOR]

Light curves of 57 classical Be stars in TESS sectors 1–15 are examined. In most Be stars, the periodogram shows groups at a fundamental and one or more harmonics, which we attribute to rotation. In about 40 per cent of the stars, the group is just a single narrow or slightly broadened peak. In about 30 per cent, it consists of a multiple, closely spaced peaks. These groups can be interpreted as non-coherent variations most likely associated with photospheric gas clouds. Approximate rotational frequencies for about 74 per cent of the stars can be derived. Comparison with the projected rotational velocities shows that the photometric frequency is consistent with rotation. The first harmonic plays a prominent role in many Be stars and manifests itself in either single-wave or double-wave light curves. The reduction in amplitude of β Cep pulsations in a few Be stars during an outburst and their subsequent recovery is most likely an obscuration effect. Other instances of possible obscuration of the photosphere are suspected. A simple model, which attempts to explain these observations and other general properties of Be stars, is proposed. [ABSTRACT FROM AUTHOR]

The study aimed to compare differences of physiological acid-base balance (ABB) parameters in follicular fluid (FF) and venous blood (VB) and to evaluate ABB parameters in FF collected from different ovarian follicles in dairy cows and heifers. The ABB parameters (pH, pCO2, pO2, HCO3- and base excess (BE)) in the FF of the preovulatory follicle, of the dominant follicle on the 9th day of the cycle and of the superovulatory estrous follicles were compared to VB. Similarly, the dynamics of the ABB profile in FF and VB were monitored in repeated sampling in a group of heifers stimulated by follicle-stimulating hormone (FSH). Higher values of pH and pO2 and lower values of pCO2, HCO3- and BE were found in FF compared to VB in all experiments. Laterality of ovaries, time of sampling, ovarian activity or stimulation of the follicular development by FSH did not significantly influence ABB parameters. We found higher pH (7.392 ± 0.027 vs. 7.364 ± 0.032) and pO2 (13.83 ± 2.20 kPa vs. 4.50 ± 0.67 kPa), lower pCO2 (5.70 ± 0.39 kPa vs. 6.54 ± 0.61 kPa), HCO3- (25.51 ± 1.52 mmol/l vs. 26.86 ± 2.12 mmol/l) and BE (1.14 ± 1.57 mmol/l vs. 1.95 ± 2.2 mmol/l) in FF compared to VB in all non-stimulated cows. Similar relationships between FF and VB were found in all FSH stimulated cows. The study provides as yet unknown knowledge on the physiology of follicular fluid in cattle. [ABSTRACT FROM AUTHOR]

The recently discovered binary LB-1 has been reported to contain a ~70, M⊙ black hole (BH). The evidence for the unprecedentedly high mass of the unseen companion comes from reported radial velocity (RV) variability of the H α emission line, which has been proposed to originate from an accretion disc around a BH. We show that there is in fact no evidence for RV variability of the H α emission line, and that its apparent shifts instead originate from shifts in the luminous star's H α absorption line. If not accounted for, such shifts will cause a stationary emission line to appear to shift in antiphase with the luminous star. We show that once the template spectrum of a B star is subtracted from the observed Keck/HIRES spectra of LB-1, evidence for RV variability vanishes. Indeed, the data rule out periodic variability of the line with velocity semi-amplitude KHα > 1.3 km s−1⁠. This strongly suggests that the observed H α emission does not originate primarily from an accretion disc around a BH, and thus that the mass ratio cannot be constrained from the relative velocity amplitudes of the emission and absorption lines. The nature of the unseen companion remains uncertain, but a 'normal' stellar-mass BH with mass 5 ≲ M/M⊙ ≲ 20 seems most plausible. The H α emission likely originates primarily from circumbinary material, not from either component of the binary. [ABSTRACT FROM AUTHOR]

We report the discovery of a square axisymmetric circumstellar nebula around the emission-line star HD 93795 in the archival Spitzer Space Telescope 24  |$\rm{\mu m}$| data. We classify HD 93795 as a B9 Ia star using optical spectra obtained with the Southern African Large Telescope (SALT). A spectral analysis carried out with the stellar atmosphere code fastwind indicates that HD 93795 only recently left the main sequence and is evolving redward for the first time. We discuss possible scenarios for the origin of the nebula and suggest that HD 93795 was originally a binary system and that the nebula was formed because of the merger of the binary components. We also discuss a discrepancy between distance estimates for HD 93795 based on the Gaia data and the possible membership of this star of the Car OB1 association, and conclude that HD 93795 could be at the same distance as Car OB1. [ABSTRACT FROM AUTHOR]

We present near-infrared interferometric AMBER observations of the B[e] binary V921 Sco at low (R ∼ 30) and medium spectral resolution (R ∼ 1500) in the K and H bands. Low spectral resolution AMBER data were used to estimate the position of the companion V921 Sco B and confirmed a clockwise movement on sky with respect to the primary of 33° between 2008 and 2012. Our observations resolve for the first time higher order Brackett lines (Br6–Br12). The modelling of the different line transitions revealed a decrease in the size of the line-emitting regions from Br3 to Br12. We are able to reproduce this decrease with a simple radiative transfer model of an equatorial disc in local thermodynamic equilibrium. In addition to the Brackett series, we also resolve permitted and forbidden Fe line emission. Our modelling shows that these lines originate from ∼2 au from the star, corresponding roughly to the measured dust sublimation region. This might indicate that the forbidden line emission arises from shock excitation at the base of a disc wind. [ABSTRACT FROM AUTHOR]

The melting process of aluminophosphate and boro-alumino-phosphate glass containing up to 5.63 wt % of beryllium oxide is studied. The viscosity and electrical conductivity of the melts are studied. The entrainment of beryllium in the steam-gas phase during glass melting is studied. The homogeneity of beryllium distribution over the glass volume is studied. The uniformity of the types of glass obtained and their structure are determined. The structural changes caused by the thermal impact on the glass samples are studied. The chemical stability of the obtained glass up to leaching Be, 137Cs, and 90Sr in contact with distilled water is determined. The possibility of the vitrification of Be-containing HLW with the formation of a glass-like matrix of the required quality (BeO content of 3.7 wt %) is shown. The results of waste recycling on an industrial scale using an EP-500/5 furnace are given. [ABSTRACT FROM AUTHOR]

In this paper, an attempt has been made to provide QoS in WiMAX IEEE 802.16 with fairness which is a challenging issue due to limited bandwidth and limited energy. To overcome these an attempt has been made in OPNET (Optimized Network Engineering Tool) which is a powerful network simulator. A appropriate classification approach in modern communication is on hand that is the usage of QoS managed via the community network operator. By developing a new System methodology to QoS with fairness by means of incorporating some principle concepts like UGS, ERTPS, RTPS, BE for VoIP, Video, HTTP to provide equal bandwidth allocation to all users in network. To get QoS along with fairness in WiMAX network, we need to overcome the issues like limited bandwidth and limited energy. This methodology proposes some other planning scheme mirroring the prerequisite of RTPS and the distinct NRTPS associations that accomplish the best ideal QoS requirement, excluding the immoderate aid consumption due to the fact that it maximizes delay for low-throughput applications as well as achieves low average, offers fairness regardless of version variation in server potential, and computationally efficient. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study aimed to evaluate the possibility of cotton waste enrichment with glycine betaine (GB) for production of two strains (P9, P10) of king oyster (Pleurotus eryngii). Cotton waste was used as (100%) control (T0 = cotton waste) and augmented with various combinations of GB, (T1 = 2 mmol L−1, T2 = 4 mmol L−1, T3 = 6 mmol L−1, T4 = 8 mmol L−1 and T5 = 10 mmol L−1). The response of king oyster to GB was evaluated by earliness, yield, biological efficiency (BE), minerals (nitrogen, phosphorus, potassium, zinc (Zn), copper (Cu), magnesium (Mg), manganese (Mn), iron (Fe), sodium (Na), calcium (Ca)), total sugars, total soluble solids, reducing sugars, non‐reducing sugars, ascorbic acid, proximate (crude protein, carbohydrates, crude fibers, ash, fats) content of fruiting body and Fourier‐transform infrared (FTIR) spectroscopy analysis compared with the control substrate (cotton waste). RESULTS: The earliness, yield, and BE were higher as compared to control substrate and increased with an augmentation in the concentration of GB within the cotton waste. Two strains showed (on dry weight basis) 33.9–54.9 mg g−1 nitrogen, 6.8–12.5 mg g−1 phosphorus, 16.9–25.1 mg g−1 potassium, 40.5–64.2 mg kg−1 Zn, 17.1–37.3 mg kg−1 Cu, 1174–1325 mg kg−1 Mg, 20.1–29.1 mg kg−1 Mn, 129–265 mg kg−1 Fe, 779–835 mg kg−1 Ca), 6.3%–11.3% total sugars, 7.3–14.9 °Brix total soluble solids, 2.1–7.3% reducing sugars, 10.4–18.1% crude protein, 3.6–4.4% crude fiber and 5.6–16.7 mg (100 g)‐1 on various concentration of GB enrich cotton waste. Cotton waste enriched with GB significantly affected nutritional profile of king oyster mushroom. CONCLUSION: The results revealed that GB enriched cotton waste can be used as an innovative substrate to enhance the yield and quality of king oyster mushroom. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Binary systems formed by early-type stars with strong winds are known to display variable non-thermal radio emission, thermal X-rays, and, at least in one case (Eta Carina), γ rays. Some of these systems are quite eccentric and the conditions for efficient particle acceleration and γ-ray production might manifest only occasionally. In this paper, I briefly review the physics of colliding wind binaries with emphasis on the observational signatures of non-thermal particle acceleration. I discuss, in particular, the case of the system HD 93129A which is made up of an O2 If* star (the primary) and an O3.5 V star (the secondary). The primary is among the earliest, hottest, most massive, luminous, and windy O stars in the Galaxy. The periastron passage during 2018 will offer an outstanding observational window that will be exploited by an international multi-wavelength campaign. [ABSTRACT FROM AUTHOR]

In this paper we present results of spectroscopic analysis of the H® line profile of the Be star 60 Cygni. We present time evolution of the equivalent width of the H® line profiles during years 1992 - 2016 and V=R variation during years 1995 - 2016. We analyzed data from Ondřejov Observatory and from BeSS Database. The circumstellar disk of the star was present twice during years 1992 - 2016 and the second cycle shows stronger emission activity. We found out that the formation of the disk takes longer time than the disk extinction (the extinction is much steeper than the formation) and that there is no evident period of changes in the V=R variation.

Giant outbursts of Be/X-ray binaries may occur when a Be-star disc undergoes strong eccentricity growth due to the Kozai–Lidov (KL) mechanism. The KL effect acts on a disc that is highly inclined to the binary orbital plane provided that the disc aspect ratio is sufficiently small. The eccentric disc overflows its Roche lobe and material flows from the Be star disc over to the companion neutron star causing X-ray activity. With N -body simulations and steady state decretion disc models we explore system parameters for which a disc in the Be/X-ray binary 4U 0115+634 is KL unstable and the resulting time-scale for the oscillations. We find good agreement between predictions of the model and the observed giant outburst time-scale provided that the disc is not completely destroyed by the outburst. This allows the outer disc to be replenished between outbursts and a sufficiently short KL oscillation time-scale. An initially eccentric disc has a shorter KL oscillation time-scale compared to an initially circular orbit disc. We suggest that the chaotic nature of the outbursts is caused by the sensitivity of the mechanism to the distribution of material within the disc. The outbursts continue provided that the Be star supplies material that is sufficiently misaligned to the binary orbital plane. We generalize our results to Be/X-ray binaries with varying orbital period and find that if the Be star disc is flared, it is more likely to be unstable to KL oscillations in a smaller orbital period binary, in agreement with observations. [ABSTRACT FROM AUTHOR]

In this paper we report on the optical and X-ray behaviour of the Be X-ray binary, SXP 91.1, during a recent type I outburst. We monitored the outburst using the Neil Gehrels Swift Observatory. These data were supported by optical data from the Southern African Large Telescope and the Optical Gravitational Lensing Experiment (OGLE) to show the circumstellar disc activity. Matter from this disc accretes on to the neutron star, giving rise to the X-ray outburst as seen in the synchronous evolution of the optical and X-ray light curves. Using data taken with OGLE we show that the circumstellar disc has exhibited stable behaviour over two decades. A positive correlation is seen between the colour and magnitude from the OGLE and massive compact halo object observations, which indicates that the disc is orientated at relatively low-inclination angles. From the OGLE and Swift data, we demonstrate that the system has shown relative phase offsets that have persisted for many years. The spin period derivative is seen to be at maximum spin-up at phases when the mass accretion rate is at maximum. We show that the neutron star in SXP 91.1 is an unusual member of its class in the sense that it has had a consistent spin period derivative over many years, with the average spin-up rate being one of the highest for known Small Magellanic Cloud pulsars. The most recent measurements of the spin-up rate reveal higher values than the global trend, which is attributed to the recent mass accretion event leading to the current outburst. [ABSTRACT FROM AUTHOR]

The available six archival XMM–Newton observations of the anomalous X-ray emitter γ Cas (B0.5 IVe) have been surveyed for the presence of soft X-ray 'dips' in X-ray light curves. In addition to discovering such events in the soft band (≤2 keV), we show that sometimes they are accompanied by minor, nearly simultaneous dips in the hard X-ray band. Herein, we investigate how these occurrences can be understood in the 'magnetic star–disc interaction' hypothesis proposed in the literature to explain the hard, variable X-ray emission of this Be star. In this scenario, the soft X-ray dips are interpreted as transits by comparatively dense, soft X-ray-absorbing blobs that move across the lines of sight to the surface of the Be star. We find that these blobs have similar properties as the 'cloudlets' responsible for migrating subfeatures in UV and optical spectral lines and therefore may be part of a common distribution of co-rotating occulters. The frequencies, amplitudes, and longevities of these dips vary widely. Additionally, the most recent spectra from 2014 July suggest that the 'warm' (kT ≈ 0.6–4 keV) plasma sources responsible for some of the soft flux are much more widely spread over the Be star's surface than the hot plasma sites that dominate the flux at all X-ray energies. We finally call attention to a sudden drop in all X-ray energies of the 2014 light curve of γ Cas and a similar sudden drop in a light curve of the 'analog' HD 110432. We speculate that these could be related to appearances of particularly strong soft X-ray dips several hours earlier. [ABSTRACT FROM AUTHOR]

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Context. Only a few open clusters are as important for the study of stellar and substellar objects, and their formation and evolution, as the young σ Orionis cluster. However, a complete spectroscopic characterisation of its whole stellar population is still missing. Aims. We filled most of that gap with a large spectroscopic and astrometric survey of targets towards σ Orionis. Eventually, it will be one of the open clusters with the lowest proportion of interlopers and the largest proportion of confirmed cluster members with known uncontrovertible youth features. Methods. We acquired 317 low-resolution optical spectra with the Intermediate Dispersion Spectrograph (IDS) at the 2.5 m Isaac Newton Telescope (INT) and the Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS) at the 10.4 m Gran Telescopio Canarias (GTC). We measured equivalent widths of Li I, Hα, and other key lines from these spectra, and determined spectral types. We complemented this information with Gaia DR2 astrometric data and other features of youth (mid-infrared excess, X-ray emission) compiled with Virtual Observatory tools and from the literature. Results. Of the 168 observed targets, we determined for the first time spectral types of 39 stars and equivalent widths of Li I and Hα of 34 and 12 stars, respectively. We identified 11 close (ρ ≲ 3 arcsec) binaries resolved by Gaia, of which three are new, 14 strong accretors, of which four are new and another four have Hα emission shifted by over 120 km s−1, two juvenile star candidates in the sparse population of the Ori OB1b association, and one spectroscopic binary candidate. Remarkably, we found 51 non-cluster-members, 35 of which were previously considered as σ Orionis members and taken into account in high-impact works on, for example, disc frequency and initial mass function. [ABSTRACT FROM AUTHOR]

Reliable determination of the basic physical properties of hot emission-line binaries with Roche-lobe filling secondaries is important for developing the theory of mass exchange in binaries. It is not easy, however, due to the presence of circumstellar matter. Here, we report the first detailed investigation of a new representative of this class of binaries, HD 81357, based on the analysis of spectra and photometry from several observatories. HD 81357 was found to be a double-lined spectroscopic binary and an ellipsoidal variable seen under an intermediate orbital inclination of ∼(63 ± 5)°, having an orbital period of 33.d. d $ {{\overset{\text{ d}}{.}}} $ 77445(41) and a circular orbit. From an automated comparison of the observed and synthetic spectra, we estimate the component's effective temperatures to be 12930(540) K and 4260(24) K. The combined light-curve and orbital solutions, also constrained by a very accurate Gaia Data Release 2 parallax, give the following values of the basic physical properties: masses 3.36 ± 0.15 and 0.34 ± 0.04M⊙N 0.34 ± 0.04 M ⊙ N $ 0.34\pm0.04\,{\mathcal{M}^\mathrm{N}_\odot} $ , radii 3.9 ± 0.2 and 13.97 ± 0.05R⊙N 13.97 ± 0.05 R ⊙ N $ 13.97\pm0.05\,{\mathcal{R}^\mathrm{N}_\odot} $ , and a mass ratio 10.0 ± 0.5. Evolutionary modelling of the system including the phase of mass transfer between the components indicated that HD 81357 is a system observed in the final slow phase of the mass exchange after the mass-ratio reversal. Contrary to what has been seen for similar binaries like AU Mon, no cyclic light variations were found on a time scale an order of magnitude longer than the orbital period. [ABSTRACT FROM AUTHOR]

We investigated 12 unclassified B[e] stars or candidates, 8 from the Galaxy, 2 from the Large Magellanic Cloud (LMC), and 2 from the Small Magellanic Cloud (SMC). Based on the analysis of high-resolution spectroscopic (FEROS) and photometric data, we confirmed the presence of the B[e] phenomenon for all objects of our sample, except for one (IRAS 07455-3143). We derived their effective temperature, spectral type, luminosity class, interstellar extinction and, using the distances from Gaia DR2, we obtained their bolometric magnitude, luminosity, and radius. Modelling of the forbidden lines present in the FEROS spectra revealed information about the kinematics and geometry of the circumstellar medium of these objects. In addition, we analysed the light curves of four stars, finding their most probable periods. The evolutionary stage of 11 stars of our sample is suggested from their position on the HR diagram, taking into account evolutionary tracks of stars with solar, LMC, and SMC metallicities. As results, we identified B and B[e] supergiants, B[e] stars probably at the main sequence or close to its end, post-AGB and HAeB[e] candidates, and A[e] stars in the main sequence or in the pre-main sequence. However, our most remarkable results are the identification of the third A[e] supergiant (ARDB 54, the first one in the LMC), and of an 'LBV impostor' in the SMC (LHA 115-N82). [ABSTRACT FROM AUTHOR]

As the largest population of high-mass X-ray binaries, Be/X-ray binaries provide an excellent laboratory to investigate the extreme physics of neutron stars. It is generally accepted that Be stars possess a circumstellar disc, providing an additional source of accretion to the stellar winds present around young hot stars. Interaction between the neutron star and the disc is often the dominant accretion mechanism. A large amount of work has gone into modelling the properties of these circumstellar discs, allowing for the explanation of a number of observable phenomena. In this paper, smoothed particle hydroynamics simulations are performed whilst varying the model parameters (orbital period, eccentricity, the mass ejection rate of the Be star, and the viscosity and orientation of the disc). The relationships between the model parameters and the disc's characteristics (base gas density, the accretion rate of the neutron star, and the disc's size) are presented. The observational evidence for a dependence of the size of the Be star's circumstellar disc on the orbital period (and semimajor axis) is supported by the simulations. [ABSTRACT FROM AUTHOR]

• Review of base editing, including recent advances and new editing variants. • Practical considerations for design and implementation of base editing experiments. • Detailed experimental examples for base editing in cell lines and organoids. Base editing is a powerful technology that enables programmable conversion of single nucleotides in the mammalian genome. Base editors consist of a partially active Cas9 nuclease (Cas9D10A) tethered to a natural or synthetic DNA modifying enzyme. Though only recently described, BE has already shown enormous potential for basic and translational research, allowing the creation or repair of disease alleles in a variety of cell types and model organisms. In the past 2 years, a vast array of new and modified base editor variants have been described, expanding the flexibility and usefulness of the approach. Though simple in concept, effective implementation of base editing requires an understanding of the advantages and limitations of each of these tools. Here, we provide an overview of the concepts of DNA base editing, and discuss the recent progress toward the development of optimized base editing systems for mammalian cells. In addition, we highlight key technical aspects of designing and executing BE experiments, and provide detailed experimental examples of successful base editing in cell lines and organoids to help guide the effective use of these tools for genome modification. [ABSTRACT FROM AUTHOR]

SXP 5.05 is a Be/X-ray binary with a neutron star companion located in the Small Magellanic Cloud. It was first detected in 2013, and later that year, SXP 5.05 underwent a massive optical and X-ray outburst. This outburst dwarfs any other optical event that has been observed for this system during the last 5 yr. The large increase in optical brightness of the system implies an increase in the size and density of the Be star's circumstellar disc. The X-ray data show two occultations of the neutron star per orbit and are not consistent with a neutron star passing behind the Be star, and hence the disc is responsible for these occultations. In this paper, we model the outburst of Be/neutron star binary SXP 5.05 as being due to a large increase in mass ejection by the Be star. The neutron star passes directly through the growing disc, and it is shown that the resulting obscuration can qualitatively explain the observed X-ray behaviour of the system. We find the only way to reproduce the time-scales of the observed optical behaviour of the system is to increase the mass ejection substantially for a short time (<2 orbits) and to decrease the viscosity during the event. The general behaviour of the observed X-ray and H α line emission are also reproduced by the model. However, the inferred mass ejection and viscosity needed to produce a sufficiently rapid increase of disc size are both higher than suggested by previous works. [ABSTRACT FROM AUTHOR]

SXP4.78 was originally discovered in 2000 as a pulsar in the Small Magellanic Cloud by the Rossi X-ray Timing Explorer, but it was not spatially located at that time. A new detection in 2018 with the Neil GehrelsSwift Observatory during a Type II outburst permitted its position to be accurately located and its optical counterpart to be identified. We report X-ray and optical monitoring covering epochs before and during the outburst. Using photometric data, we show the long-term variability of the Be disc where we present flux and colour changes associated with the disc growth and decay over a period of ∼6000 d. We show evidence of disc growth during the recent outburst through an increase in the H α equivalent width and photometric flux. Period analysis was performed using both optical photometric and spectroscopic data, but with no significant detection of an orbital period. A modest periodic signature of 2.65 d was detected from the Optical Gravitational Lensing Experiment (OGLE) I -band data, but we attribute that to the non-radial pulsations of the Be star. We also obtained a blue spectrum from the Southern African Large Telescope, which permits us to classify the spectral type as B0.5 IV–V. [ABSTRACT FROM AUTHOR]

We studied the disc of the unclassified B[e] star HD 50138 in order to explore its structure and to find indications for the evolutionary status of this system, whether it is a young Herbig Be or a post-main-sequence star. Using high spatial resolution interferometric measurements from MIDI instrument (N -band) on the Very Large Telescope Interferometer, we analysed the disc size, the time-variability of the disc's thermal emission, and the spectral shape of the |$10~\mu$| m silicate feature. By fitting simple disc models, we determined the inclination and the mid-infrared size of the disc, confirming earlier results based on a lower number of observations. We searched for mid-infrared temporal variability of different regions of the disc, and concluded that its morphology is not experiencing significant changes over the observed epochs. We characterized the mid-infrared silicate feature by determining the feature amplitude and the |$11.3/9.8~\mu$| m flux ratio. The latter parameter is a good indicator of the grain size. The shape of the feature suggests the presence of crystalline silicate grains in the disc. The interferometric data revealed a strong radial trend in the mineralogy: while the disc's innermost region seems to be dominated by forsterite grains, at intermediate radii both forsterite and enstatite may be present. The outer disc may predominantly contain amorphous silicate particles. A comparison of the observed spectral shape with that of a sample of intermediate-mass stars (supergiants, Herbig Ae/Be stars, unclassified B[e] stars) implied that the evolutionary state of HD 50138 cannot be unambiguously decided from mid-IR spectroscopy. [ABSTRACT FROM AUTHOR]

We revisit the determination of binary mass ratio in the Galactic microquasar SS433 based on recent GRAVITY VLTI measurements of mass and angular momentum outflow through a circumbinary disc. The new observations combined with the constancy of the binary orbital period over ∼30 yr confirm that the mass ratio in SS433 is q  =  M x/ M v ≳ 0.6. For the assumed optical star mass M v ranging from ∼8 to 15 |$\, \mathrm{M}_\odot$| such a mass ratio suggests a low limit of the compact object mass of |$M_\mathrm{x}\sim 5\text{--}9 \, \mathrm{M}_\odot$|⁠, placing the compact object in SS433 as a stellar mass black hole. [ABSTRACT FROM AUTHOR]

We report the discovery of a circular shell centred on the Be X-ray binary (BeXB) SXP 1323 in the Small Magellanic Cloud. The shell was detected in an H α image obtained with the Very Large Telescope. Follow-up spectroscopy with the Southern African Large Telescope showed that the shell expands with a velocity of |${\approx }100{\rm \, km\, s^{-1}}$| and that its emission is due to shock excitation. We suggest that this shell is a remnant of the supernova explosion that led to the formation of SXP 1323's neutron star |${\approx }40\, 000$|  yr ago. SXP 1323 represents the second known case of a BeXB associated with a supernova remnant (the first one is SXP 1062). Interestingly, both of these BeXBs harbour long-period pulsars and are located in a low-metallicity galaxy. [ABSTRACT FROM AUTHOR]

High resolution spectra of stars in the ≈200 Myr LMC globular cluster, NGC 1866, reveal rapidly rotating stars with variable H α emission and absorption, and signatures of outflowing material. The variable H α line can substantially affect photometric measurements obtained with HST/WFC3 narrow-band filters. [ABSTRACT FROM AUTHOR]

Background & Aims African American and European American individuals have a similar prevalence of gastroesophageal reflux disease (GERD), yet esophageal adenocarcinoma (EAC) disproportionately affects European American individuals. We investigated whether the esophageal squamous mucosa of African American individuals has features that protect against GERD-induced damage, compared with European American individuals. Methods We performed transcriptional profile analysis of esophageal squamous mucosa tissues from 20 African American and 20 European American individuals (24 with no disease and 16 with Barrett's esophagus and/or EAC). We confirmed our findings in a cohort of 56 patients and analyzed DNA samples from patients to identify associated variants. Observations were validated using matched genomic sequence and expression data from lymphoblasts from the 1000 Genomes Project. A panel of esophageal samples from African American and European American subjects was used to confirm allele-related differences in protein levels. The esophageal squamous-derived cell line Het-1A and a rat esophagogastroduodenal anastomosis model for reflux-generated esophageal damage were used to investigate the effects of the DNA-damaging agent cumene-hydroperoxide (cum-OOH) and a chemopreventive cranberry proanthocyanidin (C-PAC) extract, respectively, on levels of protein and messenger RNA (mRNA). Results We found significantly higher levels of glutathione S-transferase theta 2 (GSTT2) mRNA in squamous mucosa from African American compared with European American individuals and associated these with variants within the GSTT2 locus in African American individuals. We confirmed that 2 previously identified genomic variants at the GSTT2 locus, a 37-kb deletion and a 17-bp promoter duplication, reduce expression of GSTT2 in tissues from European American individuals. The nonduplicated 17-bp promoter was more common in tissue samples from populations of African descendant. GSTT2 protected Het-1A esophageal squamous cells from cum-OOH–induced DNA damage. Addition of C-PAC increased GSTT2 expression in Het-1A cells incubated with cum-OOH and in rats with reflux-induced esophageal damage. C-PAC also reduced levels of DNA damage in reflux-exposed rat esophagi, as observed by reduced levels of phospho-H2A histone family member X. Conclusions We found GSTT2 to protect esophageal squamous cells against DNA damage from genotoxic stress and that GSTT2 expression can be induced by C-PAC. Increased levels of GSTT2 in esophageal tissues of African American individuals might protect them from GERD-induced damage and contribute to the low incidence of EAC in this population. Graphical abstract [ABSTRACT FROM AUTHOR]

We have found three new luminous blue variable (LBV) candidates in the star-forming galaxy NGC 4736. They show typical well-known LBV spectra, broad and strong hydrogen lines, He  i lines, many Fe  ii lines, and forbidden [Fe  ii ] and [Fe  iii ]. Using archival Hubble Space Telescope and ground-based telescope data, we have estimated the bolometric magnitudes of these objects from −8.4 to −11.5, temperatures, and reddening. Source NGC 4736_1 (M |$v$|  = −10.2 ± 0.1 mag) demonstrated variability between 2005 and 2018 as Δ V ≈ 1.1 mag and Δ B ≈ 0.82 mag; the object belongs to LBV stars. NGC 4736_2 (M |$v$| < −8.6 mag) shows P Cyg profiles and its spectrum has changed from 2015 to 2018. The brightness variability of NGC 4736_2 is Δ V ≈ 0.5 mag and Δ B ≈ 0.4 mag. In NGC 4736_3 (M |$v$|  = −8.2 ± 0.2 mag), we found strong nebular lines, broad wings of hydrogen; the brightness variation is only ≈0.2 mag. Therefore, the last two objects may reside to LBV candidates. [ABSTRACT FROM AUTHOR]

Abstract Experimentally measured BEs are commercially available in various forms, e.g. scientific journals, handbooks, internet based data-banks, computer-based data-banks of BEs or complete sets of actual spectra. This review addresses fundamental problems that exist in experimentally measured binding energies (BEs) stored in various numerical X-ray Photoelectron Spectroscopy (XPS) data-banks, including, for example: (1) PHI Handbook of XPS (1979), (2) NIST SRD-20 XPS Database, v1.0–4.1 (1989–2017), (3) Wiley Practical Surface Analysis 1st and 2nd ed. (1990), (4) SASJ ComPro v12 and Data-bank (1990–2017), (5) JEOL Handbook of XPS (1991), (6) CRC Practical Handbook of Spectroscopy (1991), (7) PHI Handbook of XPS, 2nd Ed. (1992), (8) AVS Surface Science Spectra (1993–2017), (9) LaSurface Web Site Database – XPS (2001–2017), and (10) Biesinger XPSfitting website (2012–2017). The 3 major problems in all existing data-banks are due to: (a) the widespread use of different calibration energies, (b) the widespread use of different energy scales, and (c) the widespread use of a "user-defined" BE for the C 1s peak attributed to hydrocarbon moieties. At the end of this review there is a list of recommendations for the design and content of future XPS data-banks. [ABSTRACT FROM AUTHOR]

We investigate the feasibility of detecting quiescent black hole X-ray binaries using optical photometric techniques. To test this, we employ a combination of r -band and H α filters currently available at the Roque de los Muchachos Observatory. Photometric observations of four dynamical black holes (GRO J0422 |$+$| 320, A 0620-00, XTE J1118 |$+$| 480, and XTE J1859 |$+$| 226) at SNR ≳ 35–50, supplemented with near simultaneous spectroscopic data, demonstrate that it is possible to recover the full width at half-maximum of the H α emission line to better than 10 per cent for targets with a wide range of line equivalent widths and down to magnitude r ∼ 22. We further explore the potential of our photometric system to disentangle other populations of compact stars and H α emitters. In particular, we show that HAWKs, a survey designed to unveil quiescent black holes, will also provide a detailed census of other Galactic populations, most notably short period (eclipsing) cataclysmic variables, neutron star X-ray binaries, and ultracompact binaries. [ABSTRACT FROM AUTHOR]