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In this study we combine asteroseismic, spectroscopic and kinematic information to perform a detailed analysis of a sample of 16 stars from the Kepler field. Our selection focuses on stars that appear to contradict Galactic chemical evolution models: young and $\alpha$-rich, old and metal-rich, as well as other targets with unclear classification in past surveys. Kinematics are derived from Gaia DR3 parallaxes and proper motions, and high-resolution spectra from HIRES/Keck are used to calculate chemical abundances for over 20 elements. This information is used to perform careful checks on asteroseismic masses and ages derived via grid-based modelling. Among the seven stars previously classified as young and $\alpha$-rich, only one seems to be an unambiguously older object masking its true age. We confirm the existence of two very old ($\geq$11 Gyr), super metal rich ($\geq$0.1 dex) giants. These two stars have regular thin disc chemistry and in-plane solar circle orbits which fit well in the picture of radial migration via the churning mechanism. The alternative explanation that these stars have younger ages would require mass-loss rates which strongly increases with increasing metallicity. Finally, we suggest further investigations to explore the suitability of Zn as a chemical clock in red giants., Comment: 10 pages, 7 figures, accepted for publication in MNRAS

The assembly history of the Milky Way (MW) is a rapidly evolving subject, with numerous small accretion events and at least one major merger proposed in the MW's history. Accreted alongside these dwarf galaxies are globular clusters (GCs), which act as spatially coherent remnants of these past events. Using high precision differential abundance measurements from our recently published study, we investigate the likelihood that the MW clusters NGC 362 and NGC 288 are galactic siblings, accreted as part of the Gaia-Sausage-Enceladus (GSE) merger. To do this, we compare the two GCs at the 0.01 dex level for 20+ elements for the first time. Strong similarities are found, with the two showing chemical similarity on the same order as those seen between the three LMC GCs, NGC 1786, NGC 2210 and NGC 2257. However, when comparing GC abundances directly to GSE stars, marked differences are observed. NGC 362 shows good agreement with GSE stars in the ratio of Eu to Mg and Si, as well as a clear dominance in the r- compared to the s-process, while NGC 288 exhibits only a slight r-process dominance. When fitting the two GC abundances with a GSE-like galactic chemical evolution model, NGC 362 shows agreement with both the model predictions and GSE abundance ratios (considering Si, Ni, Ba and Eu) at the same metallicity. This is not the case for NGC 288. We propose that the two are either not galactic siblings, or GSE was chemically inhomogeneous enough to birth two similar, but not identical clusters with distinct chemistry relative to constituent stars., Comment: Second paper in a series. Accepted for publication by MNRAS, 17 pages, 11 figures. Minor corrections and updates made after helpful feedback from the community, thank you!

The view of globular clusters (GCs) as simple systems continues to unravel, revealing complex objects hosting multiple chemical peculiarities. Using differential abundance analysis, we probe the chemistry of the Type I GC, NGC 288 and the Type II GC, NGC 362 at the 2\% level for the first time. We measure 20 elements and find differential measurement uncertainties on the order 0.01-0.02 dex in both clusters. The smallest uncertainties are measured for Fe I in both clusters, with an average uncertainty of $\sim$0.013 dex. Dispersion in the abundances of Na, Al, Ti I, Ni, Fe I, Y, Zr, Ba and Nd are recovered in NGC 288, none of which can be explained by a spread in He. This is the first time, to our knowledge, a statistically significant spread in $s$-process elements and a potential spread in metallicity has been detected in NGC 288. In NGC 362, we find significant dispersion in the same elements as NGC 288, with the addition of Co, Cu, Zn, Sr, La, Ce, and Eu. Two distinct groups are recovered in NGC 362, separated by 0.3 dex in average differential $s$-process abundances. Given strong correlations between Al and several $s$-process elements, and a significant correlation between Mg and Si, we propose that the $s$-process rich group is younger. This agrees with asymptotic giant branch star (AGB) enrichment between generations, if there is overlap between low- and intermediate-mass AGBs. In our scenario, the older population is dominated by the $r$-process with a $\Delta^{\mathrm{La}}-\Delta^{\mathrm{Eu}}$ ratio of $-0.16\pm0.06$. We propose that the $r$-process dominance and dispersion found in NGC 362 are primordial., Comment: First paper in a series. Accepted for publication in MNRAS

In this work, we synthesized five novel iron-based trimetallic layered double hydroxides (LDHs) by the urea-assisted co-precipitation method for the electrocatalytic water oxidation reaction (WOR).

Objective Patients with dizziness may present with symptoms of tilting, swaying, rocking, floating or with disequilibrium. This may be suggestive of an isolated otolithic dysfunction yet, there is little emphasis on this emerging clinical entity. To characterize and describe the prevalence of isolated otolith dysfunction in a local tertiary hospital and correlate them with clinical diagnosis. Methodology Retrospective medical chart review of patients who presented with dizziness to the specialist outpatient Otolaryngology clinic, who required vestibular laboratory investigation. Results Of the 206 patients, more than half of them (52.4%) fulfilled the criteria for either probable or definite isolated otolith dysfunction. When there are clinical symptoms of otolith dysfunction reported, there is a 1.62 odds of a remarkable laboratory otolith finding. The most common clinical finding was “no clear diagnosis” (65.5%) followed by Vestibular Migraine (13.6%). Conclusion: The prevalence of isolated otolith dysfunction is quite high. Laboratory tests of otolith function should be performed more routinely. This can be done in a sequential way to optimize cost effectiveness in countries with no insurance reimbursement. Prospective cohort studies on isolated otolith dysfunction, will lay the groundwork for achieving diagnostic consensus and formulating rehabilitation plans to aid this group of patients.

BACKGROUND: Recently, the frequent occurrence of air pollution greatly affects people’s health. OBJECTIVE: It aims to explore the spatial non-stationarity of PM2.5. METHODS: Geographically Weighted Regression (GWR) model is applied to fit spatial structure to linear regression model. The basic principles of GWR model are introduced. Bandwidth of weight function is optimized. Then, health risk of residents in northeast China is appraised according to PM2.5 distribution characteristics. A model for phycological health risk appraisal is established. RESULTS: From the linear analysis between the fitting results by designed GWR model and ground observation, the determination coefficient is 0.7, Relative Accuracy (RA) is 0.62, Mean Prediction Error (MPE) is 25.3, and Root Mean Squared Error (RMSE) is 26.2. The model prediction results are superior to those of ordinary multivariate regression model. Moreover, the risk of respiratory and cardiovascular diseases in the elderly is positively correlated with PM2.5 exposure. The illness of the elderly is related to weather factors such as average temperature, air pressure, and relative humidity. CONCLUSIONS: The study provides a reference for the research on risk of illness of people in PM2.5 environment.

A major goal in the discovery and characterization of exoplanets is to identify terrestrial-type worlds that are similar to (or otherwise distinct from) our Earth. The combination of mass-radius measurements and host stellar abundances has been proposed to constrain the interiors of small (rocky) exoplanets. In this work, we advocate the importance of using devolatilized stellar abundances, instead of uncorrected stellar abundances, to further reduce degeneracies in modelling the interiors of rocky exoplanets. We apply an empirical devolatilization model to a selected sample of 13 planet-hosting Sun-like stars, for which high-precision photospheric abundances have been available. With the resultant devolatilized stellar composition (i.e. the model planetary bulk composition), as well as other constraints including mass and radius, we model the detailed mineralogy and interior structure of hypothetical, habitable-zone terrestrial planets (‘exo-Earths’) around these stars. Model output shows that most of these exo-Earths are expected to have broadly Earth-like composition and interior structure, consistent with conclusions derived independently from analysis of polluted white dwarfs. Investigating the empirical devolatilization model at its extremes as well as varying planetary mass and radius (within the terrestrial regime) reveals potential diversities in the interiors of terrestrial planets. By considering (i) high-precision stellar abundances, (ii) devolatilization, and (iii) planetary mass and radius holistically, this work represents essential steps to explore the detailed mineralogy and interior structure of terrestrial-type exoplanets, which in turn are fundamental for a quantitative understanding of planetary long-term evolution including the interior-atmosphere interactions., EPSC Abstracts, 16

In this work, we synthesized five novel iron-based trimetallic layered double hydroxides (LDHs) by the urea-assisted co-precipitation method for the electrocatalytic water oxidation reaction (WOR). In particular, the synthesized electrocatalysts were labeled CoCuFe-LDH, ZnNiFe-LDH, ZnCoFe-LDH, ZnCuFe-LDH, and CoGaFe-LDH. The electrocatalysts were thoroughly characterized by means of Ultraviolet-visible spectroscopy (UV-Vis), N

In this work we combine information from solar-like oscillations, high-resolution spectroscopy and Gaia astrometry to derive stellar ages, chemical abundances and kinematics for a group of seven metal-poor Red Giants and characterise them in a multidimensional chrono-chemo-dynamical space. Chemical abundance ratios were derived through classical spectroscopic analysis employing 1D LTE atmospheres on Keck/HIRES spectra. Stellar ages, masses and radii were calculated with grid-based modelling, taking advantage of availability of asteroseismic information from Kepler. The dynamical properties were determined with Galpy using Gaia EDR3 astrometric solutions. Our results suggest that underestimated parallax errors make the effect of Gaia parallaxes more important than different choices of model grid or -- in the case of stars ascending the RGB -- mass-loss prescription. Two of the stars in this study are identified as potentially evolved halo blue stragglers. Four objects are likely members of the accreted Milky Way halo, and their possible relationship with known accretion events is discussed., Comment: 15 pages, 8 figures, accepted for publication in MNRAS

Star formation models predict that the metal-poor initial mass function (IMF) can be substantially different from that observed in the metal-rich Milky Way. This changeover occurs because metal-poor gas clouds cool inefficiently due to their lower abundance of metals and dust. However, predictions for the metal-poor IMF to date rely on assuming Solar-scaled abundances, that is, [X/O] = 0 at all [O/H]. There is now growing evidence that elements such as C and O that dominate metal line cooling in the ISM do not follow Solar scaling at low metallicities. In this work, we extend models that predict the variation in the characteristic (or, the peak) IMF mass as a function of metallicity using [C/O] ratios derived from observations of metal-poor Galactic stars and of H II regions in dwarf galaxies. These data show [C/O] < 0 at sub-Solar [O/H], which leads to a substantially different metal-poor IMF in the metallicity range where C I and C II cooling dominate ISM thermodynamics, resulting in an increase in the characteristic mass by a factor as large as 7. An important consequence of this difference is a shift in the location of the transition from a top- to a bottom-heavy IMF upwards by 0.5 $-$ 1 dex in metallicity. Our findings indicate that the IMF is very sensitive to the assumptions around Solar-scaled ISM compositions in metal-poor systems (e.g., dwarf galaxies, the Galactic halo and metal-poor stars) that are a key focus of JWST., 14 pages, 8 figures. Accepted by MNRAS

Accurate stellar parameters of stars in open clusters can help constrain models of stellar structure and evolution. Here we wish to determine the age and metallicity content of the open cluster NGC 2506. To this end we investigated three detached eclipsing binaries (DEBs; V2032, V4, and V5) for which we determined their masses and radii, as well as four red giant branch stars for which we determined their effective temperatures, surface gravities, and metallicities. Three of the stars in the DEBs have masses close to the cluster turn-off mass, allowing for extremely precise age determination. Comparing the values for the masses and radii of the binaries to BaSTI isochrones we estimated a cluster age of $2.01 \pm 0.10$ Gyr. This does depend on the models used in the comparison, where we have found that the inclusion of convective core-overshooting is necessary to properly model the cluster. From red giant branch stars we determined values for the effective temperatures, the surface gravities, and the metallicities. From these we find a cluster metallicity of $-0.36 \pm 0.10$ dex. Using this value and the values for the effective temperatures we determine the reddening to be E$(b - y) = 0.057 \pm 0.004$ mag. Furthermore, we derived the distance to the cluster from Gaia parallaxes and found $3.101 \pm 0.017$ kpc, and we have performed a radial velocity membership determination for stars in the field of the cluster. Finally, we report on the detection of oscillation signals in $\gamma$ Dor and $\delta$ Scuti members in data from the TESS mission, including the possible detection of solar-like oscillations in two of the red giants., Comment: 30 pages, 16 figures, accepted for publication in MNRAS

The low-metallicity, kinematically interesting dwarf stars studied by Stephens \& Boesgaard (2002, SB02) are re-examined using Gaia DR2 astrometry, and updated model atmospheres and atomic line data. New stellar parameters are determined based on the Gaia DR2 parallactic distances and Dartmouth Stellar Evolution Database isochrones. These are in excellent agreement with spectroscopically determined stellar parameters for stars with [Fe/H]$>-2$; however, large disagreements are found for stars with [Fe/H]$\le-2$, with offsets as large as $\Delta$T$_{\rm eff}\sim+500$ K and $\Delta$log\,$g\sim+1.0$. A subset of six stars (test cases) are analysed ab initio using high resolution spectra with Keck HIRES and Gemini GRACES. This sub-sample is found to include two $\alpha$-challenged dwarf stars, suggestive of origins in a low mass, accreted dwarf galaxy. The orbital parameters for the entire SB02 sample are re-determined using \textit{Gaia} DR2 data. We find 11 stars that are dynamically coincident with the \textit{Gaia}-Sausage accretion event and another 17 with the \textit{Gaia}-Sequoia event in action space. Both associations include low-mass, metal-poor stars with isochrone ages older than 10 Gyr. Two dynamical subsets are identified within \textit{Gaia}-Sequoia. When these subsets are examined separately, a common knee in [$\alpha$/Fe] is found for the \textit{Gaia}-Sausage and low orbital energy \textit{Gaia}-Sequoia stars. A lower metallicity knee is tentatively identified in the \textit{Gaia}-Sequoia high orbital energy stars. If the metal-poor dwarf stars in these samples are true members of the \textit{Gaia}-Sausage and \textit{Gaia}-Sequoia events, then they present a unique opportunity to probe the earlier, more pristine, star formation histories of these systems.

ObjectivesUnderstanding the pattern of middle-ear cholesteatoma becomes pertinent with the rise of endoscopic surgery as surgeons decide on the optimal approach to visualise and extirpate disease. With modifications to the Telmesani attic–tympanum–mastoid staging system, this study aimed to evaluate the commonest patterns of middle-ear cholesteatoma and their implications for surgical approach.MethodsA retrospective study was conducted in a single tertiary institution in Singapore. All patients undergoing cholesteatoma surgery between January 2012 and June 2015 were included.Staging of cholesteatoma was based on clinical assessment corroborated by radiological findings.ResultsOut of the 55 ears included, 98.2 per cent had cholesteatoma involving the attic. The disease extended into the mastoid antrum and beyond in 43 cases (78.2 per cent). The facial recess and/or sinus tympanum was affected in 26 cases (47.3 per cent).ConclusionThe majority of cholesteatoma cases present with extensive attic disease and significant mastoid involvement. In these cases, endoscopes may be best suited to adjunctive rather than exclusive use in surgery.

We combine asteroseismology, optical high-resolution spectroscopy, and kinematic analysis for 26 halo red giant branch stars in the \textit{Kepler} field in the range of $-2.52$), which constrains a relative age dispersion to $-1.7$ into two [{Mg}/{Fe}] groups. While [$\alpha$/{Fe}] and [{Eu}/{Mg}] ratios are different between the two subsamples, [$s$/Eu], where $s$ stands for Ba, La, Ce, and Nd, does not show a significant difference. These abundance ratios suggest that the chemical evolution of the low-Mg population is contributed by type~Ia supernovae, but not by low-to-intermediate mass asymptotic giant branch stars, providing a constraint on its star formation timescale as $100\,\mathrm{Myr}, Comment: 44 pages. accepted version

Observations of stellar chemical compositions enable us to identify connections between globular clusters and stellar populations in the Milky Way. In particular, chemical abundance ratios provide detailed insight into the chemical enrichment histories of star clusters and the field populations. For some elements, there are striking differences between field and cluster stars which reflect different nucleosynthetic processes and/or chemical evolution. The goal of this talk was to provide an overview of similarities and differences in chemical compositions between globular clusters and the Milky Way as well as highlighting a few areas for further examination.

We have investigated the thorium (Th) abundance in a sample of 53 thin disc solar twins covering a wide range of ages. These data provide constrains on the mantle energy budget of terrestrial planets that can be formed over the evolution of the Galaxy's thin disc. We have estimated Th abundances with an average precision of 0.025\,dex (in both [Th/H] and [Th/Fe]) through comprehensive spectral synthesis of a Th\,II line present at 4019.1290\,{\AA}, using very high resolution (R\,=\,115,000) high quality HARPS spectra obtained at the ESO La Silla Observatory. We have confirmed that there is a large energy budget from Th decay for maintaining mantle convection inside potential rocky planets around solar twins, from the Galactic thin disc formation until now, because the pristine [Th/H]$_{\rm ZAMS}$ is super-solar on average under a uniform dispersion of 0.056\,dex (varying from +0.037 up to +0.138\,dex based on linear fits against isochrone stellar age). Comparing to neodymium (Nd) and europium (Eu), two others neutron-capture elements, the stellar pristine abundance of Th follows Eu along the Galactic thin disc evolution, but it does not follow Nd, probably because neodymium has a significant contribution from the $s$-process (about 60\,per\,cent)., Comment: 13 pages & 6 figures; accepted for publication in MNRAS

Conservative pulp therapy is an alternative treatment option to tooth removal and root canal treatment in the management of deep caries, traumatic pulp exposures and developmental anomalies. Pulp tissue preservation can extend the long-term survival of teeth through relatively simple restorative procedures. This article aims to update clinicians on the current state of research in materials, techniques and outcomes of vital pulp therapies and provide practical guidelines for their implementation into daily practice.

We present chemical abundances for 21 elements (from Li to Eu) in 150 metal-poor Galactic stars spanning $-$4.1 $$ $-$3.5. Of the 20 objects for which we could measure nitrogen, 11 are nitrogen-enhanced metal-poor stars. Within our sample, the high NEMP fraction (55\% $\pm$ 21\%) is compatible with the upper range of predicted values (between 12\% and 35\%). The chemical abundance ratios [X/Fe] versus [Fe/H] exhibit similar trends to previous studies of metal-poor stars and Galactic chemical evolution models. We report the discovery of nine new r-I stars, four new r-II stars, one of which is the most metal-poor known, nine low-$\alpha$ stars with [$\alpha$/Fe] $\le$ 0.15 as well as one unusual star with [Zn/Fe] = +1.4 and [Sr/Fe] = +1.2 but with normal [Ba/Fe]. Finally, we combine our sample with literature data to provide the most extensive view of the early chemical enrichment of the Milky Way Galaxy., Comment: MNRAS in press (see source file for full versions of long tables)

Binary star systems are assumed to be co-natal and coeval, thus to have identical chemical composition. In this work we aim to test the hypothesis that there is a connection between observed element abundance patterns and the formation of planets using binary stars. Moreover, we also want to test how atomic diffusion might influence the observed abundance patterns. We conduct a strictly line-by-line differential chemical abundance analysis of 7 binary systems. Stellar atmospheric parameters and elemental abundances are obtained with extremely high precision (< 3.5%) using the high quality spectra from VLT/UVES and Keck/HIRES. We find that 4 of 7 binary systems show subtle abundance differences (0.01 - 0.03 dex) without clear correlations with the condensation temperature, including two planet-hosting pairs. The other 3 binary systems exhibit similar degree of abundance differences correlating with the condensation temperature. We do not find any clear relation between the abundance differences and the occurrence of known planets in our systems. Instead, the overall abundance offsets observed in the binary systems (4 of 7) could be due to the effects of atomic diffusion. Although giant planet formation does not necessarily imprint chemical signatures onto the host star, the differences in the observed abundance trends with condensation temperature, on the other hand, are likely associated with diverse histories of planet formation (e.g., formation location). Furthermore, we find a weak correlation between abundance differences and binary separation, which may provide a new constraint on the formation of binary systems., 15 pages, 16 figures; accepted by MNRAS

Neutron-star mergers were recently confirmed as sites of rapid-neutron-capture (r-process) nucleosynthesis. However, in Galactic chemical evolution models, neutron-star mergers alone cannot reproduce the observed element abundance patterns of extremely metal-poor stars, which indicates the existence of other sites of r-process nucleosynthesis. These sites may be investigated by studying the element abundance patterns of chemically primitive stars in the halo of the Milky Way, because these objects retain the nucleosynthetic signatures of the earliest generation of stars. Here we report the element abundance pattern of the extremely metal-poor star SMSS J200322.54-114203.3. We observe a large enhancement in r-process elements, with very low overall metallicity. The element abundance pattern is well matched by the yields of a single 25-solar-mass magnetorotational hypernova. Such a hypernova could produce not only the r-process elements, but also light elements during stellar evolution, and iron-peak elements during explosive nuclear burning. Hypernovae are often associated with long-duration gamma-ray bursts in the nearby Universe. This connection indicates that similar explosions of fast-spinning strongly magnetized stars occurred during the earliest epochs of star formation in our Galaxy., Comment: Author's version of a Letter published in Nature on July 8th, 2021

This study aims to evaluate the surgical outcomes with the use of a combination of the middle temporal artery (MTA) flap and the inferior musculoperiosteal (IMP) flap for mastoid obliteration after canal wall down mastoidectomy. Seventy-five patients who have undergone canal wall down mastoidectomy and mastoid obliteration with the MTA and the IMP flaps at a single tertiary hospital were included. Surgical outcomes measured included the creation of a dry mastoid cavity as measured by a previously developed semi-quantitative scale, mastoid cavity epithelization time, rate of revision surgery needed, and rate of recurrent cholesteatoma. Patients were followed up for a median of 29 months. The median time to epithelization of the mastoid cavity was 2 months. At 1 and 3 months, 36.0% and 76.0% of patients had grade 0 and grade 1 cavities, respectively, with either a dry cavity or one or less episodes of mild otorrhea or sensation of wetness. Hundred percent of the patients achieved a grade 2 (more than one episode of otorrhea or the presence of granulation tissue that promptly resolved with simple treatment) or better cavity at 3 months. One patient re-presented with a grade 3 cavity with uncontrolled infection and daily otorrhea secondary to an attic perforation that manifested at 6 months, requiring revision surgery. There were no recurrent cholesteatomas during the follow-up period. The use of the MTA and the IMP flaps for mastoid obliteration may be considered as an adjunct to achieving a safe, dry ear after canal wall down mastoidectomy.

There is significant variation in practices concerning Roux-en-Y gastric bypass (RYGB) among bariatric surgeons, but there is currently a lack of robust data on the nature and extent of these variations. The purpose of this study was to understand global variations in practices concerning RYGB. A questionnaire-based survey on Survey Monkey® was created, and the link was shared freely on various social media platforms. The link was also distributed through a personnel email network of authors. A total of 657 surgeons from 65 countries completed the survey. Crohn’s disease and liver cirrhosis were considered absolute contraindications for RYGB by 427 surgeons (64.98%) and 347 surgeons (53.30%), respectively. More than 68.5% of surgeons performed routine upper GI endoscopy while 64.17% performed routine ultrasound of abdomen preoperatively. The majority of surgeons (77.70%) used the perigastric technique for Gastric pouch creation. Approximately, 79.5% used orogastric bougie. More than 70% of the respondents did not use any staple line reinforcement routinely. Only 17.67% of surgeons measured the whole small bowel length, and the majority of surgeons (86.5%) used constant length of BP limb. Approximately, 89% used constant length of alimentary limb. Approximately, 95% of surgeons preferred antecolic bypass, and more than 86% routinely closed the Petersen defect. Marginal ulcer prophylaxis was used by the majority (91.17%). Almost 95% of surgeons recommended lifelong vitamin and mineral supplements. This survey identifies global variations in practices concerning RYGB. It identifies several areas for future research and consensus building.

We present a line-by-line differential analysis of a sample of 16 planet hosting stars and 68 comparison stars using high resolution, high signal-to-noise ratio spectra gathered using Keck. We obtained accurate stellar parameters and high-precision relative chemical abundances with average uncertainties in \teff, \logg, [Fe/H] and [X/H] of 15 K, 0.034 [cgs], 0.012 dex and 0.025 dex, respectively. For each planet host, we identify a set of comparison stars and examine the abundance differences (corrected for Galactic chemical evolution effect) as a function of the dust condensation temperature, \tcond, of the individual elements. While we confirm that the Sun exhibits a negative trend between abundance and \tcond, we also confirm that the remaining planet hosts exhibit a variety of abundance $-$ \tcond\ trends with no clear dependence upon age, metallicity or \teff. The diversity in the chemical compositions of planet hosting stars relative to their comparison stars could reflect the range of possible planet-induced effects present in these planet hosts, from the sequestration of rocky material (refractory poor), to the possible ingestion of planets (refractory rich). Other possible explanations include differences in the timescale, efficiency and degree of planet formation or inhomogeneous chemical evolution. Although we do not find an unambiguous chemical signature of planet formation among our sample, the high-precision chemical abundances of the host stars are essential for constraining the composition and structure of their exoplanets., Comment: 14 pages, 10 figures, accepted for publication in MNRAS

In this work we combine spectroscopic information from the \textit{SkyMapper survey for Extremely Metal-Poor stars} and astrometry from Gaia DR2 to investigate the kinematics of a sample of 475 stars with a metallicity range of $ -6.5 \leq \rm [Fe/H] \leq -2.05$ dex. Exploiting the action map, we identify 16 and 40 stars dynamically consistent with the \textit{Gaia Sausage} and \textit{Gaia Sequoia} accretion events, respectively. The most metal-poor of these candidates have metallicities of $\rm [Fe/H]=-3.31$ and $\rm [Fe/H]=-3.74$, respectively, helping to define the low-metallicity tail of the progenitors involved in the accretion events. We also find, consistent with other studies, that $\sim$21\% of the sample have orbits that remain confined to within 3~kpc of the Galactic plane, i.e., |Z$_{max}$| $\leq$ 3~kpc. Of particular interest is a sub-sample ($\sim$11\% of the total) of low |Z$_{max}$| stars with low eccentricities and prograde motions. The lowest metallicity of these stars has [Fe/H] = --4.30 and the sub-sample is best interpreted as the very low-metallicity tail of the metal-weak thick disk population. The low |Z$_{max}$|, low eccentricity stars with retrograde orbits are likely accreted, while the low |Z$_{max}$|, high eccentricity pro- and retrograde stars are plausibly associated with the \textit{Gaia Sausage} system. We find that a small fraction of our sample ($\sim$4\% of the total) is likely escaping from the Galaxy, and postulate that these stars have gained energy from gravitational interactions that occur when infalling dwarf galaxies are tidally disrupted., Comment: 23 pages, 15 figures, accepted for publication in MNRAS

The origin of multiple stellar populations in Globular Clusters (GCs) is one of the greatest mysteries of modern stellar astrophysics. N-body simulations suggest that the present-day dynamics of GC stars can constrain the events that occurred at high redshift and led to the formation of multiple populations. Here, we combine multi-band photometry from the Hubble Space Telescope (HST) and ground-based facilities with HST and Gaia Data Release 2 proper motions to investigate the spatial distributions and the motions in the plane of the sky of multiple populations in the type II GCs NGC 5139 ($\omega\,$Centauri) and NGC 6656 (M 22). We first analyzed stellar populations with different metallicities. Fe-poor and Fe-rich stars in M 22 share similar spatial distributions and rotation patterns and exhibit similar isotropic motions. Similarly, the two main populations with different iron abundance in $\omega\,$Centauri share similar ellipticities and rotation patterns. When analyzing different radial regions, we find that the rotation amplitude decreases from the center towards the external regions. Fe-poor and Fe-rich stars of $\omega\,$Centauri are radially anisotropic in the central region and show similar degrees of anisotropy. We also investigate the stellar populations with different light-element abundances and find that their N-rich stars exhibit higher ellipticity than N-poor stars. In $\omega\,$Centauri Centauri both stellar groups are radially anisotropic. Interestingly, N-rich, Fe-rich stars exhibit different rotation patterns than N-poor stars with similar metallicities. The stellar populations with different nitrogen of M 22 exhibit similar rotation patterns and isotropic motions. We discuss these findings in the context of the formation of multiple populations., Comment: 24 pages, 13 figures, accepted for publication in ApJ

We present a detailed study of stellar rotation in the massive 1.5 Gyr old cluster NGC 1846 in the Large Magellanic Cloud. Similar to other clusters at this age, NGC 1846 shows an extended main sequence turn-off (eMSTO), and previous photometric studies have suggested it could be bimodal. In this study, we use MUSE integral-field spectroscopy to measure the projected rotational velocities (vsini) of around 1400 stars across the eMSTO and along the upper main sequence of NGC 1846. We measure vsini values up to ~250 km/s and find a clear relation between the vsini of a star and its location across the eMSTO. Closer inspection of the distribution of rotation rates reveals evidence for a bimodal distribution, with the fast rotators centred around vsini = 140 km/s and the slow rotators centred around vsini = 60 km/s. We further observe a lack of fast rotating stars along the photometric binary sequence of NGC 1846, confirming results from the field that suggest that tidal interactions in binary systems can spin down stars. However, we do not detect a significant difference in the binary fractions of the fast and slowly rotating sub-populations. Finally, we report on the serendipitous discovery of a planetary nebula associated with NGC 1846., Comment: Accepted for publication in MNRAS, 15 pages, 10 figures

We present new fluorine abundance estimations in two carbon enhanced metal-poor (CEMP) stars, HE 1429-0551 and HE 1305+0007. HE 1429-0551 is also enriched in slow neutron-capture process (s-process) elements, a CEMP-s, and HE 1305+0007 is enhanced in both, slow and rapid neutron-capture process elements, a CEMP-s/r. The F abundances estimates are derived from the vibration-rotation transition of the HF molecule at 23358.6 A using high-resolution infrared spectra obtained with the Immersion Grating Infrared Spectrometer (IGRINS) at the 4m-class Lowell Discovery Telescope. Our results include a F abundance measurement in HE 1429-0551 of A(F) = +3.93 ([F/Fe] = +1.90) at [Fe/H] = -2.53, and a F upper limit in HE 1305+0007 of A(F) < +3.28 ([F/Fe] < +1.00) at [Fe/H] = -2.28. Our new derived F abundance in HE 1429-0551 makes this object the most metal-poor star where F has been detected. We carefully compare these results with literature values and state-of-the-art CEMP-s model predictions including detailed AGB nucleosynthesis and binary evolution. The modelled fluorine abundance for HE 1429-0551 is within reasonable agreement with our observed abundance, although is slightly higher than our observed value. For HE 1429-0551, our findings support the scenario via mass transfer by a primary companion during its thermally-pulsing phase. Our estimated upper limit in HE 1305+0007, along with data from the literature, shows large discrepancies compared with AGB models. The discrepancy is principally due to the simultaneous s- and r-process element enhancements which the model struggles to reproduce., 12 pages, 5 Figures -- Accepted in MNRAS

We present the characterization of CRTS J055255.7$-$004426 (=THOR 42), a young eclipsing binary comprising two pre-main sequence M dwarfs (combined spectral type M3.5). This nearby (103 pc), short-period (0.859 d) system was recently proposed as a member of the $\sim$24 Myr-old 32 Orionis Moving Group. Using ground- and space-based photometry in combination with medium- and high-resolution spectroscopy, we model the light and radial velocity curves to derive precise system parameters. The resulting component masses and radii are $0.497\pm0.005$ and $0.205\pm0.002$ $\rm{M}_{\odot}$, and $0.659\pm0.003$ and $0.424\pm0.002$ $\rm{R}_{\odot}$, respectively. With mass and radius uncertainties of $\sim$1 per cent and $\sim$0.5 per cent, respectively, THOR 42 is one of the most precisely characterized pre-main sequence eclipsing binaries known. Its systemic velocity, parallax, proper motion, colour-magnitude diagram placement and enlarged radii are all consistent with membership in the 32 Ori Group. The system provides a unique opportunity to test pre-main sequence evolutionary models at an age and mass range not well constrained by observation. From the radius and mass measurements we derive ages of 22-26 Myr using standard (non-magnetic) models, in excellent agreement with the age of the group. However, none of the models can simultaneously reproduce the observed mass, radius, temperature and luminosity of the coeval components. In particular, their H-R diagram ages are 2-4 times younger and we infer masses $\sim$50 per cent smaller than the dynamical values., Accepted for publication in MNRAS. 22 pages. Tables 4 and 5 are available in full as ancillary files

PurposeThis paper aims to derive determinants of loan loss provisions (LLPs) of commercial banks in Malaysia.Design/methodology/approachA single-stage panel data analysis multiple regression model that contains a mixture of quantitative and qualitative elements is used. The LLPs is a dependent variable or regressor, and non-performing loan (NPL), interest income, net profit, loans and advances and gross domestic product (GDP) are the independent variables or regressor/explanatory variables. The moderating variable is “credit risk management” (CRM) and the intervening variable is “relevance and faithful representation”.FindingsThis paper suggests in LLPs, NPLs, interest income, loans and advances, net profit and GDP, as well as the moderating effect of CRM and the intervening effect of relevance and faithful representation, are determinants of the LLPs. The moderating variable CRM strengthens the relationship between the independent variables and the dependent variable. The intervening variable “relevance and faithful representation” brings about a more accurate reporting on the levels of the LLPs.Practical implicationsThe association of the factors is investigated further to detect possible effect of multicollinearity and research to better understand how banks manage their risk as the current investigation is limited to banks in Malaysia.Social implicationsLoan loss provisioning issues of commercial banks in Malaysia are challenges for both regulators and the banking industry owing to the implementation of several new measures, the convergence with internationally accepted accounting standards and differences in loan grading and applications of different loan loss provisioning standards. Because of these challenges, Bank Negara Malaysia (the Central Bank of Malaysia) has tightened its supervision of commercial banks to ensure that banks are sufficiently and adequately provisioned. The banking sector plays a significant role, and it is important that it is resilient in the face of potential sources of systemic risk. And, like in other major ASEAN economies, the Malaysian’s financial system remains largely bank-dominated.Originality/valueThis study discovers whether Malaysian banks are sufficiently provisioned for the regional financial integration under the ASEAN Capital Markets Forum (ACMF) by the end of 2015, where several initiates have been initiated, including the harmonization of standards to encourage greater intra-regional investment flows and transactions and continued provisions of the much needed funds by the region’s private sectors.