bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of Healthcare Providers in Return to Work
Authors: Kosny Agnieszka , Lifshen Marni , Yanar Basak , Tonima Sabrina , MacEachen Ellen , Furlan Andrea , Koehoorn Mieke , Beaton Dorcas , Cooper Juliette , Neis Barbara
Published: August 2018

International research has generated strong evidence that healthcare providers (HCPs) play a key role in the return to work (RTW) process. However, pressure on consultation time, administrative challenges and limited knowledge about a patient's workplace can thwart meaningful engagement. Aim: Our study sought to understand how HCPs interact with workers compensation boards (WCBs), manage the treatment of workers compensation patients and navigate the RTW process. Method: The study involved in-depth interviews with 97 HCPs in British Columbia, Manitoba, Ontario and Newfoundland and Labrador and interviews with 34 case managers (CMs). An inductive, constant comparative analysis was employed to develop key themes. Findings: Most HCPs did not encounter significant problems with the workers compensation system or the RTW process when they treated patients who had visible, acute, physical injuries, but faced challenges when they encountered patients with multiple injuries, gradual-onset or complex illnesses, chronic pain and mental health conditions. In these circumstances, many experienced the workers compensation system as opaque and confusing. A number of systemic, process and administrative hurdles, disagreements about medical decisions and lack of role clarity impeded the meaningful engagement of HCPs in RTW. In turn, this has resulted in challenges for injured workers (IWs), as well as inefficiencies in the workers compensation system. Conclusion: This study raises questions about the appropriate role of HCPs in the RTW process. We offer suggestions about practices and policies that can clarify the role of HCPs and make workers compensation systems easier to navigate for all stakeholders.
A FLOW OF WEALTH: WASTEWATER DISPOSAL IN REPUBLICAN TIANJIN
Authors: Mu Cao
Published: August 2018

Tianjin is the largest port city in Northern China and a major hub for water and land transportation. For geological reasons, the city has long been troubled by water drainage problems. To remove wastewater from within its walls, the city developed a drain system which relies on human labor and a series of variously sized ditches. Unlike the modern sewage system, which simply discharges wastewater into surrounding rivers and the sea, Tianjin's traditional wastewater disposal system worked in concert with an urban manure collection system. Urban wastewater was recycled as fertilizer, a valuable resource for the surrounding rural area. In tracing the origin, evolution, and influence of urban wastewater disposal in Tianjin, this article aims to reveal the potential value in Chinese traditional waste management practices. Contemporary urban waste disposal systems might benefit from a better understanding of the relationship between urban and rural areas that characterized these traditional practices.
On the couple dynamics of wall-mounted flexible plates in tandem
Authors: Jin Y. , Kim J.-T. , Mao Z. , Chamorro L. P.
Published: August 2018

The dynamics of two rectangular, flexible plates of low aspect ratio $h/b$ (height/width = 4) was experimentally investigated in tandem arrangements under uniform flows at various Cauchy numbers $Ca=\unicode[STIX]{x1D70C}_{f}bU_{0}^{2}h^{3}/(EI)\in [15,77]$ (where $\unicode[STIX]{x1D70C}_{f}$ is the fluid density, $U_{0}$ is the incoming flow velocity, $E$ is the Young’s modulus and $I$ is the second moment of the area) and spacings $s_{x}=\unicode[STIX]{x0394}x/h=0.5$, 1 and 2. Planar particle image velocimetry (PIV) and particle tracking velocimetry (PTV) were used to characterize the surrounding flow field and oscillations of the wall-mounted structures. Results show that the oscillations of the upstream plate were dominated by its natural frequency. However, the motions of the downstream plate were significantly modulated by the induced flow and coherent motions shed from the upstream structure. Such modulation led to highly correlated motions between the plates with similar amplitude in the case $s_{x}=0.5$, to comparatively larger oscillation amplitude of the downstream plate in the intermediate separation $s_{x}=1$, and roughly decoupled interaction for $s_{x}=2$. Despite that the intensity of the oscillations of the upstream plate increased monotonically with $Ca$, this was not the case for the downstream plate at $s_{x}=1$ and 2 due to flow fluctuations, vortex shedding and large structure deformation; as a result, it exhibited a local minimum. Supported with measurements, a mathematical model was derived to quantitatively explain this behaviour.
Mechanical energy budget and mixing efficiency for a radiatively heated ice-covered waterbody
Authors: Ulloa Hugo N. , Wüest Alfred , Bouffard Damien
Published: August 2018

Ice-covered waterbodies are far from being quiescent systems. In this paper, we investigate ice-covered freshwater basins heated by solar radiation that penetrates across waters with temperatures below or near the temperature of maximum density. In this scenario, solar radiation sets a radiative buoyancy flux, $\unicode[STIX]{x1D6F7}_{r}$, that forces increments of temperature/density in the upper fluid volume, which can become gravitationally unstable and drive convection. The goal of this study is twofold. We first focus on formulating the mechanical energy budget, putting emphasis on the conversion of $\unicode[STIX]{x1D6F7}_{r}$ to available potential energy, $E_{a}$. We find that $E_{a}$ results from a competition among $\unicode[STIX]{x1D6F7}_{r}$ and the irreversible mixing controlled by the diapycnal and the laminar mixing rates, respectively. Secondly, and based on the above result, we introduce an integral formulation of the mixing efficiency to quantify the rate of mixing over the relevant time scale $\unicode[STIX]{x1D70F}$, $\unicode[STIX]{x1D702}_{c}\equiv \unicode[STIX]{x0394}E_{b,\unicode[STIX]{x1D70F}}/E_{r,\unicode[STIX]{x1D70F}}$, where $\unicode[STIX]{x0394}E_{b,\unicode[STIX]{x1D70F}}$ and $E_{r,\unicode[STIX]{x1D70F}}$ are the change of background potential energy and the time-integrated $\unicode[STIX]{x1D6F7}_{r}$ over $\unicode[STIX]{x1D70F}$. The above definition is applied to estimate $\unicode[STIX]{x1D702}_{c}$ for the first time, finding an approximate value of $\unicode[STIX]{x1D702}_{c}\approx 0.65$. This result suggests that radiatively heated ice-covered waterbodies might be subject to high mixing rates. Overall, the present work provides a framework to examine energetics and mixing in ice-covered waters.
Analyzing Causal Mechanisms in Survey Experiments
Authors: Acharya Avidit , Blackwell Matthew , Sen Maya
Published: August 2018

Researchers investigating causal mechanisms in survey experiments often rely on nonrandomized quantities to isolate the indirect effect of treatment through these variables. Such an approach, however, requires a “selection-on-observables” assumption, which undermines the advantages of a randomized experiment. In this paper, we show what can be learned about casual mechanisms through experimental design alone. We propose a factorial design that provides or withholds information on mediating variables and allows for the identification of the overall average treatment effect and the controlled direct effect of treatment fixing a potential mediator. While this design cannot identify indirect effects on its own, it avoids making the selection-on-observable assumption of the standard mediation approach while providing evidence for a broader understanding of causal mechanisms that encompasses both indirect effects and interactions. We illustrate these approaches via two examples: one on evaluations of US Supreme Court nominees and the other on perceptions of the democratic peace.
Peri-operative outcomes following major surgery for head and neck cancer in the elderly: institutional audit and case–control study
Authors: Subramaniam N , Balasubramanian D , Rka P , Rathod P , Murthy S , Vidhyadharan S , Rajan S , Paul J , Thankappan K , Iyer S
Published: August 2018

Objective

Elderly patients have been consistently shown to receive suboptimal therapy for cancers of the head and neck. This study was performed to determine the peri-operative outcomes of these patients and compare them with those of younger patients.

Methods

In this retrospective analysis, 115 patients aged 70 years or more undergoing major surgery for head and neck cancers were matched with 115 patients aged 50–60 years, and univariate analysis was performed.

Results

Elderly patients had a reduced performance status (p < 0.001) and more co-morbid illnesses (p = 0.007), but a comparable intra-operative course. They had a longer median hospital stay (p = 0.016), longer intensive care unit stay (p = 0.04), longer median tracheostomy dependence (p = 0.04) and were more often discharged with feeding tubes (p < 0.001). They also had a higher incidence of post-operative non-fatal cardiac events (p = 0.045).

Conclusion

Elderly patients with good performance status should receive curative-intent surgery. Although hospital stay and tube dependence are longer, morbidity and mortality are comparable with younger patients.
Tracheostomy for paediatric obstructive sleep apnoea: A systematic review
Authors: Fray S , Biello A , Kwan J , Kram Y A , Lu K , Camacho M
Published: August 2018

Objective

To search the international literature (any language) for publications reporting outcomes of tracheostomy performed to treat obstructive sleep apnoea in children.

Method

Data sources included: Google Scholar, Cumulative Index to Nursing and Allied Health Literature, Embase, Scopus, and PubMed/Medline. Four authors searched systematically through to 20 January 2018.

Results

A total of 597 studies were screened; 64 were downloaded and 11 met criteria. A total of 196 patients underwent tracheostomy (mean age, 4.2 years; range, newborn to 18 years); 40 had detailed qualitative data and 6 had detailed quantitative data. Apnoea/hypopnoea index showed a 97 per cent reduction (n= 2) and apnoea index showed a 98 per cent reduction (n= 3). Lowest oxygen saturation showed a 34 oxygen saturation point improvement (n= 3). Several patients demonstrated significant improvement in breathing. All identified patients were syndromic, had significant co-morbidities or had severe obstructive sleep apnoea.

Conclusion

Based on reports of children who have undergone a tracheostomy, for whom there are pre- and post-operative data, tracheostomy appears to be a successful treatment for obstructive sleep apnoea. However, additional research is recommended given the small number of patients in the literature.
An analogue of Khintchine's theorem for self-conformal sets
Authors: BAKER SIMON
Published: August 2018

Khintchine's theorem is a classical result from metric number theory which relates the Lebesgue measure of certain limsup sets with the convergence/divergence of naturally occurring volume sums. In this paper we ask whether an analogous result holds for iterated function systems (IFS's). We say that an IFS is approximation regular if we observe Khintchine type behaviour, i.e., if the size of certain limsup sets defined using the IFS is determined by the convergence/divergence of naturally occurring sums. We prove that an IFS is approximation regular if it consists of conformal mappings and satisfies the open set condition. The divergence condition we introduce incorporates the inhomogeneity present within the IFS. We demonstrate via an example that such an approach is essential. We also formulate an analogue of the Duffin–Schaeffer conjecture and show that it holds for a set of full Hausdorff dimension.

Combining our results with the mass transference principle of Beresnevich and Velani [4], we prove a general result that implies the existence of exceptional points within the attractor of our IFS. These points are exceptional in the sense that they are “very well approximated”. As a corollary of this result, we obtain a general solution to a problem of Mahler, and prove that there are badly approximable numbers that are very well approximated by quadratic irrationals.

The ideas put forward in this paper are introduced in the general setting of iterated function systems that may contain overlaps. We believe that by viewing iterated function systems from the perspective of metric number theory, one can gain a greater insight into the extent to which they overlap. The results of this paper should be interpreted as a first step in this investigation.
A code comparison of the interaction between Milky Way disc and satellites
Authors: Mazzarini Matteo , Just Andreas
Published: August 2018

We present a comparison of previous simulations of the interaction of the Galactic disc with the Milky Way (MW) satellites using superbox-10 with new simulations performed with gadget-2 and ChaNGa. The robust performance of gadget-2 motivates us to employ more recent versions of gadget
to identify the satellite debris in the MW halo, disc and bulge.
Is the Galactic Spiral Potential 2- or 4-arms?
Authors: Grosbøl Preben , Carraro Giovanni
Published: August 2018

Young objects (e.g. OB-associations and HII regions) in the Galaxy outline a 4-armed spiral structure whereas the tangent points of arms observed in the near-infrared indicate a 2-armed pattern. The more important issue is whether the spiral potential in the Galaxy is 2- or 4-armed i.e. if all arms traced by young objects also have a significant mass perturbation associated to them. This can be tested by studying the mean radial velocity of a well defined stellar population across the spiral arms and thereby estimating the surface density change.

The current paper presents a preliminary analysis of the radial velocities of a sample of 736 early-type stars toward the Galactic center observed with FLAMES/VLT. A comparison with N-body models in a fixed spiral potential with 2 or 4 arms suggests that no significant mass is associated to the Sagittarius arm. The data are consistent with 2-armed models with pattern speeds in the range of 15-30 km s−1 kpc−1 and relative radial forces of less than 4%.
New Highly r-Process-Enhanced Halo Stars
Authors: Beers Timothy C. , Holmbeck Erika M. , Placco Vinicius M. , Hansen Terese T. , Simon Joshua D. , Thompson Ian , Frebel Anna , Sakari Charli M.
Published: August 2018

There are roughly 25 very metal-poor (VMP; [Fe/H] < -2.0), highly r-process-enhanced (‘r-II’; [Eu/Fe] > + 1.0) stars currently known, discovered over the past 20+ years. These stars provide nearly pure signatures of r-process events early in the Galactic history. We are conducting a high-resolution follow-up survey of RAVE and other bright targets to identify a total of > 100 r-II stars. Our pilot runs on the du Pont 2.5-m at Las Campanas Observatory and the ARC 3.5-m at Apache Point Observatory have already identified up to fourteen new r-II stars. We are continuing our high-resolution follow-up efforts to constrain the astrophysical site(s) and nature of the r-process.
Kinematic structures found with Gaia DR1/TGAS and RAVE data in the Solar neighbourhood
Authors: Kushniruk I. , Schirmer T. , Bensby T.
Published: August 2018

With the much enlarged stellar sample of 55 831 stars and much increased precision in distances, proper motions, provided by Gaia DR1 TGAS we have shown with the help of the wavelet analysis that the velocity distribution of stars in the Solar neighbourhood contains more kinematic structures than previously known. We detect 19 kinematic structures between scales 3-16 km s−1 at the 3σ confidence level. Among them we identified well-known groups (such as Hercules, Sirius, Coma Berenices, Pleiades, and Wolf 630). We confirmed recently detected groups (such as Antoja12 and Bobylev16). In addition we report here about a new kinematic structure at (U, V) ≈ (37, 8) km s−1. Another three new groups are tentatively detected, but require confirmation.
The APOSTLE simulations: Rotation curves derived from synthetic 21-cm observations
Authors: Oman Kyle A.
Published: August 2018

Theapostlecosmological hydrodynamical simulation suite is a collection of twelve regions ~5 Mpc in diameter, selected to resemble the Local Group of galaxies in terms of kinematics and environment, and re-simulated at high resolution (minimum gas particle mass of 104M⊙) using the galaxy formation model and calibration developed for theeagleproject. I select a sample of dwarf galaxies (60 <Vmax/km s−1< 120) from these simulations and construct synthetic spatially- and spectrally-resolved observations of their 21-cm emission. Using the3Dbarolotilted-ring modelling tool, I extract rotation curves from the synthetic data cubes. In many cases, non-circular motions present in the gas disc hinder the recovery of a rotation curve which accurately traces the underlying mass distribution; a large central deficit of dark matter, relative to the predictions of cold dark matter N-body simulations, may then be erroneously inferred.
The age-metallicity structure of the Milky Way disc with APOGEE
Authors: Mackereth J. Ted , Bovy Jo , Schiavon Ricardo P. ,   the SDSS-IV/APOGEE Collaboration
Published: August 2018

The best way to trace back the history of star formation and mass assembly of the Milky Way disc is by combining chemical compositions, ages and phase-space information for a large number of disc stars. With the advent of large surveys of the stellar populations of the Galaxy, such data have become available and can be used to pose constraints on sophisticated models of galaxy formation. We use SDSS-III/APOGEE data to derive the first detailed 3D map of stellar density in the Galactic disc as a function of age, [Fe/H] and [α/Fe]. We discuss the implications of our results for the formation and evolution of the disc, presenting new constraints on the disc structural parameters, stellar radial migration and disc flaring. We also discuss how our results constrain the inside out formation of the disc, and determine the surface-mass density contributions at the solar radius for mono-age, mono-[Fe/H] populations.
New Views From Galactoseismology: Rethinking the Galactic Disk-Halo Connection
Authors: Sheffield Allyson A. , Johnston Kathryn V. , Price-Whelan Adrian M. , Tzanidakis Anastasios , Laporte Chervin F. P. , Li Ting , Bergemann Maria , Sesar Branimir , Carlin Jeffrey L.
Published: August 2018

We present preliminary results from a study exploring the origin of Milky Way substructures, and show initial evidence of a common “kicked-out” formation mechanism for two low-latitude substructures. In this scenario, stars in these substructures formed in the disk and were subsequently “kicked-out” by an external perturbation, such as the merger of an accreted satellite, which created an oscillation in the Galactic disk. To test this origin scenario, we found the fraction of different stellar populations – M giants and RR Lyrae stars – in the Monoceros Ring (also known as GASS) and A13, supplementing a study of stellar populations in the Triangulum-Andromeda cloud. This work provides: (1) the first analysis of the GASS and A13 features based upon their stellar populations; and (2) preliminary evidence of disk stars in the Milky Way that have been relocated to the disk-halo interface due to vertical oscillations of the Milky Way’s disk.
Open cluster study in LAMOST DR3
Authors: Zhong Jing , Chen Li , Zhang Chaoli , Shao Zhengyi , Hou Jinliang
Published: August 2018

In studying Galactic open clusters based on LAMOST DR3, we deliberately selected several nearby cluster, which have relatively large projection area and reliable proper motion measurements. For each cluster, we firstly determine the typical proper motion distribution profiles in the cluster-core and the outskirt region, respectively, and perform field-star decontamination on the cluster area. We then calculate kinematic membership probability for each star in the cluster area and cross-match the highly probable members with LAMOST DR3 spectral catalog. Based on enhanced signal of cluster-member radial velocity distribution emerging from the whole field, we have also obtained reliable radial velocity membership probability for each star. Finally, we perform isochrones fitting with MCMC technique to study basic properties of these cluster, including age, metallicity, and distance modulus.
Study of the thick disc of the Milky Way from a population synthesis model
Authors: Nasello G. , Robin A. C. , Reylé C. , Lagarde N.
Published: August 2018

The thick disc is a major component of the Milky Way but its epoch of formation and characteristics are still not yet well constrained. The Besançon Galaxy Model (BGM, Robin et al. 2003) is a population synthesis model based on a scenario of formation and evolution of the Galaxy, a star formation history, and a set of stellar evolution models. Thanks to Lagarde et al. (2017), new evolutionary tracks have been introduced into the Besancon Galaxy Model (STAREVOL, Lagarde et al. 2012) to provide global asteroseismic and surface chemical properties along the evolutionary stages. This updated Galaxy model will allow us to constrain the thick disc structure and history using the Markov Chain Monte Carlo fitting method (MCMC). We show preliminary results applying this MCMC method on the 2MASS photometric survey.
Kinematic trends in young and old stars
Authors: Wojno Jennifer , Kordopatis Georges , Steinmetz Matthias , McMillan Paul J. ,   the RAVE collaboration
Published: August 2018

Using RAVE DR5, we explore the age, kinematic, and chemical correlations of a sample of  30,000 FGK stars. We separate a sample of turnoff stars into two age groups: young and old. For each of the two age groups, we calculate kinematic trends as a function of Galactocentric radius (R), for different metallicity ([Fe/H]) bins. For both young and old stars, we measure a negative gradient in ∂〈VR〉/∂R. In addition, for young stars we find a correlation between the magnitude of the slope and metallicity, with the most metal-rich bins having the steepest gradient and the most metal-poor bins having a flatter trend.
NLTE abundances of C, O, Ca, Ti, and Fe in the reference BAF-type stars
Authors: Sitnova Tatyana , Ryabchikova Tatyana , Alexeeva Sofya , Mashonkina Lyudmila
Published: August 2018

We present accurate methods of abundance determination based on the non-local thermodynamic equilibrium (NLTE) line formation for carbon, oxygen, calcium, titanium, and iron in the atmospheres of BAF-type stars. For C I-II, O I, Ca I-II, and Ti I-II, their comprehensive model atoms were described in our previous papers. A fairly complete model atom of Fe I-II is first applied in this study. We determine the NLTE abundances of the nine BAF-type stars with well-determined atmospheric parameters, using high-resolution and high signal-to-noise ratio spectral observations in the broad wavelength range, from the UV to the IR. For C, Ca, Ti, and Fe, NLTE leads to consistent abundances from the lines of the two ionisation stages. The C I, Ca II, and Fe II emission lines were detected in the near IR spectrum of the late B-type subgiant star HD 160762. They are well reproduced in the classical hydrostatic model atmosphere, when applying our NLTE methods.
Galactoseismology in the Age of Gaia
Authors: Widrow Lawrence M. , Chequers Matthew H.
Published: August 2018

Recent observations from SEGUE, RAVE, and LAMOST have revealed tantalizing evidence that the local stellar disk of the Milky Way is in a state of disequilibrium. In particular, the disk appears to exhibit bending and breathing waves normal to its midplane within 2 kiloparsecs of our position within the disk. There also appear to be bending waves or corrugations at larger Galactocentric radii. These waves may be linked to other time-dependent disk phenomena such as the bar, spiral structure, and warp, or they may be the result of a passing dark matter subhalo or dwarf galaxy. Here, we discuss the observational evidence for these waves, the theory of bending and breathing waves in (simulated) stellar disks, and implications of disequilibrium for attempts to determine the local vertical force and dark matter density (the Oort problem). We also discuss the types of analyses that one might do with the Gaia
database.
Impacts of Radial Mixing on the Galactic Thick and Thin Disks
Authors: Kawata Daisuke
Published: August 2018

Using N-body simulations of the Galactic disks, we qualitatively study how the metallicity distributions of the thick and thin disk stars are modified by radial mixing induced by the bar and spiral arms. We show that radial mixing drives a positive vertical metallicity gradient in the mono-age disk population whose initial scale-height is constant and initial radial metallicity gradient is tight and negative. On the other hand, if the initial disk is flaring, with scale-height increasing with galactocentric radius, radial mixing leads to a negative vertical metallicity gradient, which is consistent with the current observed trend. We also discuss impacts of radial mixing on the metallicity distribution of the thick disk stars. By matching the metallicity distribution of N-body models to the SDSS/APOGEE data, we argue that the progenitor of the Milky Way’s thick disk should not have a steep negative metallicity gradient.
PARSEC evolutionary tracks and isochrones including seismic properties
Authors: Montalbán J. , Bressan A. , Girardi L. , Rodrigues T. , Bossini D. , Miglio A. , Scuflaire R. , Trabucchi M. , Marigo P.
Published: August 2018

In the recent years it has been generally accepted that seismic parameters add an important observational constraint for the study of stellar populations and galaxy evolution. Padova-Trieste (PARSEC) evolutionary tracks are widely used to characterise stellar objects and stellar populations. Stellar models at the base of these studies suffer from uncertainties and, more important, degeneracy among different input parameters: stellar mass, chemical composition, central chemical mixing, age, etc. Adding seismic properties to the classic parameters for stars at different evolutionary states, from the H main-sequence to the asymptotic giant branch, is a powerful tool to calibrate physical processes in stellar models, and hence to improve our interpretation of Galactic and extra-Galactic observations.
High-precision abundances of elements in stars with asteroseismic ages
Authors: Nissen P. E. , Aguirre V. Silva , Christensen-Dalsgaard J. , Collet R. , Grundahl F. , Slumstrup D.
Published: August 2018

High-precision abundances of elements have been derived from HARPS-N spectra of F and G main-sequence stars having ages determined from oscillation frequencies delivered by the Kepler mission. The tight relations between abundance ratios of refractory elements, e.g., [Mg/Fe] and [Y/Mg], and stellar age previously found for solar twin stars are confirmed. These relations provide new information on nucleosynthesis and Galactic evolution. Abundance ratios between volatile and refractory elements, e.g., [C/Fe] and [O/Fe], show on the other hand a significant scatter at a given age, which may be related to planet-star interactions. This is a potential problem for chemical tagging studies.
Stellar multiplicity in the Milky Way Galaxy
Authors: Stonkutė E. , Church R. P. , Feltzing S. , Johnson J. A.
Published: August 2018

We present our models of the effect of binaries on high-resolution spectroscopic surveys. We want to determine how many binary stars will be observed, whether unresolved binaries will contaminate measurements of chemical abundances, and how we can use spectroscopic surveys to better constrain the population of binary stars in the Galaxy. Using a rapid binary-evolution algorithm that enables modelling of the most complex binary systems we generate a series of large binary populations in the Galactic disc and evaluate the results. As a first application we use our model to study the binary fraction in APOGEE giants. We find tentative evidence for a change in binary fraction with metallicity.
Using open clusters as tracers of the galactic disk history
Authors: Santrich Orlando J. Katime , Rossi Silvia , Abuchaim Yuri , Gonçalves Geraldo
Published: August 2018

Open clusters are important objects to study the galactic structure and its dynamical behavior as well as the stellar formation and evolution. We carried out a spectroscopic analysis to derive atmospheric parameters and chemical composition for 52 giant stars within 9 galactic open clusters. We have used the high-resolution spectra from FEROS, HARPS and UVES in the ESO archive. The methodology used is based on LTE-hypothesis. Abundances of C, N, O, Na, Mg, Al, Si, Ca, Ti, Cr, Ni, YII, LaII, CeII, and NdII were calculated. Although most of these clusters present spectroscopic analysis in the literature, some CNO and s-process abundances were not previously estimated or were calculated with high uncertainties. Several lines of such elements were identified and used to calculate new abundances and improve some previous one.
Chemical and dynamical analysis of Open Clusters from OCCASO data. The case of NGC 6705
Authors: Casamiquela Laia , Carrera Ricardo , Balaguer-Núñez Lola , Jordi Carme , Chiappini Cristina , Antoja Teresa , Miret-Roig Núria
Published: August 2018

The OCCASO survey targets intermediate-age and old OCs visible from the Northern hemisphere. OCCASO provides homogeneous radial velocities, atmospheric parameters, and individual abundances from high-resolution spectroscopy (R>65,000) of Red Clump stars. We present a first insight into the homogeneously analyzed chemical abundances obtained fror 18 Northern OCs from OCCASO data. Our sample includes an interesting inner disk OC, NGC 6705, analyzed in the literature with inconclusive results about its α abundances. From OCCASO data this is an α-enhanced OC from the analysis of Si, Ca, Ti, Mg and O, despite its young age.
Reconstructing the star formation history of the Solar neighbourhood with Gaia
Authors: Bernard Edouard J.
Published: August 2018

Taking advantage of the Gaia DR1, we combined TGAS parallaxes with the Tycho-2 and APASS photometry to calculate the star formation history (SFH) of the solar neighbourhood within 250 pc using the colour-magnitude diagram fitting technique. Our dynamically-evolved SFH is in excellent agreement with that calculated from the Hipparcos catalogue within 80 pc of the Sun, showing an enhanced star formation rate (SFR) in the past ~4 Gyr. We then correct the SFR for the disc thickening with age to obtain a SFR that is representative of the whole solar cylinder, and show that even with an extreme correction our results are not consistent with an exponentially decreasing SFR as found by recent studies. Finally, we discuss how this technique can be applied out to ~5 kpc thanks to the next Gaia data releases, which will allow us to quantify the SFH of the thin disc, thick disc and halo in situ.
HSC Wide and Deep Imaging Survey for the Milky Way Satellite Galaxies
Authors: Komiyama Yutaka
Published: August 2018

We have carried out an imaging survey for Local Group dwarf spheroidal galaxy Ursa Minor (UMi) using Hyper Suprime-Cam (HSC) on the 8.2m Subaru Telescope. Wide and deep data obtained by HSC enable us to investigate the extent of UMi which is revealed to extend out to twice the nominal tidal radius. The fraction of binary systems is also investigated from the morphology of the main sequence and estimated to be ~0.4.
Detect the density profile with LAMOST K giants
Authors: Xu Yan , Liu Chao
Published: August 2018

The density distribution of the Milky Way halo is detected with 5351 LAMOST DR3 metal poor K giants using a nonparametric method. The nonparametric fitting method is a model independent way to estimate the halo density distribution while to a large extent avoiding the influence of the halo substucture. We show that the K giants density profile can be fitted well by single power law. We found no indication of a break in the power law index. The powerlaw index n = 5.0−0.64+0.64. The data show that the stellar halo is flattened at smaller radii, and becomes more spherical farther from the Galactic center. The flattening q(r=15Kpc)is about0.64, q(20Kpc) is about 0.8, q(30Kpc) is about 0.96.
APOGEE: the Sloan Digital Sky Survey Apache Point Observatory Galactic Evolution Experiment. Insights into the Galactic Disk: A Review
Authors: Holtzman Jon A. , Hasselquist Sten ,   the SDSS-IV/APOGEE-2 collaboration
Published: August 2018

The SDSS Apache Point Observatory Galactic Evolution Experiment (APOGEE) has collected high resolution near-IR spectra for several hundred thousand stars throughout the Milky Way. We review some of the results related to chemistry of stars in the disk, where APOGEE has a particular advantage by virtue of being able to work in more obscured areas. The ability to measure carbon and nitrogen abundances in giants in the near-IR provides insight into stellar ages. We summarize results on the variation of mean metallicity, metallicity distribution functions, and the [α/Fe]–[Fe/H] relation across the Galactic disk, as well as results on the structural parameters in mono-abundance populations. Many of these results suggest that radial migration has played a significant role in the Galactic disk. It may be possible to disentangle radial mixing using multi-element abundance patterns.
Investigation on fundamental plane of open clusters
Authors: Pang Xiao-Ying , Lin Chien-Cheng
Published: August 2018

The fundamental plane (FP) is the relation between the surface brightness (I), velocity dispersion (σ) and radius (R). The tilt of FP from the virial plane (R = σ2 I) not only tells the dynamical states of the system but also its formation and evolution. We motivate to looking for an FP in Galactic open clusters (OCs). To form a sample of OCs, we access the most recent DR 14 data from the SDSS/APOGEE2 and the Gaia-ESO survey. Membership of stars is determined via radial velocity and metallicity, plus star’s location in the color-magnitude diagram. Besides the velocity dispersion (σrv) obtained from SDSS/APOGEE2 & Gaia-ESO, the average surface brightness (IKs), and apparent radii (r2) of OCs are taken from known OC catalog. A weak relation is found: log(r2) ∝ -0.34 * log(σ) - 0.08 * IKs. An implication of this FP needs further investigation.
The RAdial Velocity Experiment: preparing the 6th Data Release chemical abundances with GAUGUIN
Authors: Guiglion Guillaume ,   THE RAVE COLLABORATION
Published: August 2018

In the context of the Radial Velocity Experiment (RAVE, Steinmetz et al. 2006), we present chemical abundances derived with the pipeline GAUGUIN. Based of 520 701 RAVE stars with medium resolution (R~7 500) spectra and stellar atmospheric parameters of the fifth Data Release, the analysis is performed around the infrared Ca-triple domain for 6 chemical elements: Mg, Ni, Si, Ti, Fe and Al. We discuss here the reliability of the chemical abundances provided by GAUGUIN, and the implications for the future Data Release 6 of the RAVE Survey. We also present elemental abundance patterns of Milky Way components based of kinematical criteria.
On The Metal-poor non-Sagittarius Globular Cluster NGC 5053: Orbit, Mg, Al, and Si
Authors: Tang Baitian
Published: August 2018

Metal-poor globular clusters (GCs) show intriguing Al-Mg and Si-Al correlations, which are important clues to decipher the multiple population phenomenon. NGC 5053 is one of the most metal-poor GCs, and has been suggested to be associated with the Sagittarius dwarf galaxy (Sgr), due to its similar location and radial velocity with one of the Sgr arms. In this work, we simulate the orbit of NGC 5053, and argue against the connection between Sgr and NGC 5053. Meanwhile, Mg, Al, and Si spectral lines, which are difficult to detect in the optical spectra, have been detected in the near-infrared APOGEE spectra. We use three different sets of stellar parameters and codes to derive the Mg, Al, and Si abundances, and we always see a large Al variation, and a substantial Si enhancement. Comparing with other metal-poor GCs, we suggest metallicity may not be the only parameter that controls the multiple populations.
Galactic Phylogenetics
Authors: Jofré Paula , Das Payel
Published: August 2018

Phylogenetics is a widely used concept in evolutionary biology. It is the reconstruction of evolutionary history by building trees that represent branching patterns and sequences. These trees represent shared history, and it is our contention that this approach can be employed in the analysis of Galactic history. In Galactic archaeology the shared environment is the interstellar medium in which stars form and provides the basis for tree-building as a methodological tool. Using elemental abundances of solar-type stars as a proxy for DNA, we built such an evolutionary tree to study the chemical evolution of the solar neighbourhood and published in Jofré15 et al. (2017). In this proceeding we summarise these results and discuss future prospects.
Probing Galactic Chemical Evolution with J-PLUS Photometry
Authors: Whitten Devin D. , Placco Vinicius M. , Beers Timothy C. , Clark Spencer , Ederoclite Alessandro , de Oliveira Cláudia Mendes
Published: August 2018

Narrow-band photometric surveys, such as the Javalambre Photometric Local Universe Survey (J-PLUS), provide not only a means of pre-selection for high-resolution follow-up, but open a new era of precision photometric stellar parameter determination. Using a family of machine learning algorithms known as Artificial Neural Networks (ANNs), we have obtained photometric estimates of effective temperature (Teff) and metallicity ([Fe/H]) across a wide parameter range of temperature and metallicity (4000 < Teff <7000 K; −3.5 <[Fe/H]<0.0) for a number of stars in the J-PLUS Early Data Release. With this methodology, we expect to increase the number of known Carbon-enhanced Metal-poor (CEMP; [C/Fe]>+0.7) stars by several orders of magnitude, as well as constrain the metallicity distribution function of the Milky Way Halo system.
The Multidimensional Structure of Math Anxiety	Revisited
Authors: Henschel Sofie , Roick Thorsten
Published: August 2018

Abstract. The study introduces a math anxiety scale that systematically addresses psychological components, including cognitive (worry) and affective (nervousness) math anxiety when dealing with mathematical problems in mathematics-related settings (concerning tests, teachers, learning in class, working with mathematics textbooks, mathematics homework, and applying mathematics in everyday life). Our results indicate a hierarchical structure of math anxiety. Specifically, cognitive and affective math anxiety at the second-order level each determined three setting factors at the first-order level concerning evaluation (tests, teachers), learning (in class, with mathematics books, and during homework), and application (applying mathematics in everyday life). Furthermore, girls reported higher math anxiety than boys, which was particularly pronounced in the affective scale and in high-stakes academic settings, such as those involving evaluation and learning. After controlling for mathematics performance, gender effects decreased in all sub-dimensions but remained significant in affective math evaluation anxiety. Practical implications and directions for further research on cognitive and affective math anxiety are discussed.
A Salutogenic Perspective on Adverse Experiences
Authors: Höltge Jan , Mc Gee Shauna L. , Maercker Andreas , Thoma Myriam V.
Published: August 2018

Abstract. Research has predominantly focused on the negative effects of adversity on health and well-being. However, the salutogenic perspective suggests that adversity may not always be detrimental ( Antonovsky, 1996 ). In fact, under certain circumstances, adversity may have the potential for positive outcomes, such as increased resilience and thriving ( Carver, 1998 ; Rutter, 1987 ). The “steeling effect” suggests that past experiences of adversity may increase resistance to later adversities. It proposes that moderate adversity may facilitate more adaptive functioning than no adversity or high levels of adversity ( Rutter, 2006 , 2012 ). The relationship between adversity and health may be optimally assessed using curvilinear models, yet the majority of previous studies have examined linear associations ( Masten & Cicchetti, 2016 ). It is therefore the aim of this review to determine whether moderate adversity is associated with more adaptive functioning when compared to no and high levels of adversity. Practical implications and future research are also discussed.
Constructing Mars: Concrete and Energy Production From Serpentinization Products
Authors: Scott Allan N. , Oze Christopher
Published: August 2018

In situ building materials and energy resources are necessary for the long‐term human habitation of Mars. Olivine ((Mg,Fe)2SiO4) is a regionally abundant mineral on Mars and may potentially serve both purposes. Here we assess olivine hydrolysis (i.e., serpentinization) and related products including magnesite (MgCO3) as a means to produce a Mg‐based cement and molecular hydrogen (H2) as an energy resource. Magnesium oxide (MgO) may be derived from Mg(OH)2 dehydration or calcination (i.e., thermal decomposition) of MgCO3. In laboratory experiments, Mg‐based concrete using MgO achieved a compressive strength in excess of 20 MPa. Serpentinization‐related H2 gas concentrations increased with increasing temperature (20 to 50 °C) and decreasing olivine particle size reaching a maximum H2 production rate of 4.73 μmol g−1 day−1, 3 orders of magnitude greater than previously observed. Results from this study indicate that serpentinization and related products serve as a viable pathway for both concrete and fuel production on Mars with minimal energy expenditure and primarily constrained to the availability of water. Moreover, this process would work equally as well on Earth and has significant potential to decrease global industrial CO2 emissions.
Physically Accurate Large Dynamic Range Pseudo Moments for the MMS Fast Plasma Investigation
Authors: Barrie A. C. , da Silva D. , Elkington S. , Sternovsky Z. , Rager A. C. , Gershman D. J. , Paterson W. R. , Dorelli J. C. , Giles B.
Published: August 2018

The Fast Plasma Investigation onboard the Magnetospheric Multiscale (MMS) mission captures full‐sky particle data over a range of 10 eV to 30 keV every 30 ms for electrons and 150 ms for ions. Only about 5% of the count data at this time resolution are sent to the ground due to telemetry limitations; however, a complete set of onboard trigger terms are sent due to their small data volume. These trigger terms are composed of simplified integrals that scale proportionally to plasma moments. They were initially conceived as a mechanism to rank scientific data for priority downlink; however, they can be adapted to represent pseudo moment quantities that are accurate to within several percent of fully corrected plasma moments. Tuning the dynamic range per plasma region and correcting via a trained neural network allow for far greater accuracy than previous missions. Corrections are performed based on statistical sampling of data from the first MMS day side pass. The corrections are validated by comparing pseudo moments to a published event showcasing detection of kinetic Alfvén waves. Physically accurate pseudo plasma moment quantities are available for the entirety of the MMS prime science regions, and can be a valuable asset for future scientific analysis of the MMS data repository.
Rising Seas Increase Methane Emissions from the Mouths of Rivers
Authors: Underwood Emily
Published: August 2018

Drowned river deltas exhale large quantities of greenhouse gas, new study finds.
AGU Announces New Education Section
Authors: McEntee Chris
Published: August 2018

The section will play an important role in developing a diverse, inclusive, and dynamic Earth and space science talent pool.
Severe Drought May Have Helped Hasten Ancient Maya’s Collapse
Authors: Duncombe Jenessa
Published: August 2018

Chemical signatures from sediments in lake cores reveal that the centuries-long drought during the fall of Classic Maya civilization was worse than researchers had imagined.
Enhancement of the Jovian Magnetospheric Plasma Circulation Caused by the Change in Plasma Supply From the Satellite Io
Authors: Tsuchiya F. , Yoshioka K. , Kimura T. , Koga R. , Murakami G. , Yamazaki A. , Kagitani M. , Tao C. , Suzuki F. , Hikida R. , Yoshikawa I. , Kasaba Y. , Kita H. , Misawa H. , Sakanoi T.
Published: August 2018

The innermost Galilean satellite, Io, supplies a large amount of volcanic gasses to the Jovian magnetosphere. The fast rotation of Jupiter and the outward transport of ionized gasses are responsible for forming a huge and rotationally dominant magnetosphere. The plasma supply from the satellite has a key role in the characterization of the Jovian magnetosphere. In fact, significant variations of the plasma population in the inner magnetosphere caused by the volcanic eruptions in Io were found in early 2015, using a continuous data set of the Io plasma torus obtained from an extreme ultraviolet spectroscope onboard the Hisaki satellite. The time evolution of the Io plasma torus radial distribution showed that the outward transport of plasma through 8 RJ from Jupiter was enhanced for approximately 2 months (from the end of January to the beginning of April 2015). Intense short‐lived auroral brightenings––which represent transient energy releases in the outer part of the magnetosphere—occurred frequently during this period. The short‐lived auroral brightenings accompanied well‐defined sporadic enhancements of the ion brightness in the plasma torus, indicating a rapid inward transport of energy from the outer part of the magnetosphere and the resultant enhancement of hot electron population in the inner magnetosphere. This evidently shows that the change in a plasma source in the inner magnetosphere affects a large‐scale radial circulation of mass and energy in a rotationally dominant magnetosphere.
Solar Cycle Response of CO2 Over the Austral Winter Mesosphere and Lower Thermosphere Region
Authors: Salinas Cornelius Csar Jude H. , Chang Loren C. , Liang Mao‐Chang , Qian Liying , Yue Jia , Lee Jae N. , Russell James , Mlynczak Martin , Wu Dong L.
Published: August 2018

This work uses Sounding of the Atmosphere using Broadband Emission Radiometry CO2 data from 2002 to 2015 and Specified Dynamics‐Whole Atmosphere Community Climate Model (SD‐WACCM) outputs from 1979 to 2014 to show, for the first time, the solar cycle response of CO2 in the Austral winter mesosphere and lower thermosphere region. Both Sounding of the Atmosphere using Broadband Emission Radiometry and SD‐WACCM show that CO2 experiences a decrease during solar maximum throughout the Austral winter mesosphere and lower thermosphere region. This work highlights the regions where CO2 experiences its strongest and weakest solar cycle responses as modeled by SD‐WACCM. The region with the strongest solar cycle response experiences around 5% reduction in CO2 between solar maximum and solar minimum. The region with weakest solar cycle response experiences less than 1% reduction in CO2 between solar maximum and solar minimum. It is shown that the region of the strongest CO2 response is driven by photodissociation, downwelling, and reduced eddy diffusion. On the other hand, the region of the weakest CO2 response is driven by the opposing effects of photodissociation and enhanced eddy diffusion. This is the first work to show that the solar cycle could affect the Austral winter lower thermosphere circulation and eddy diffusion processes. These anomalies in the lower thermospheric circulation and eddy diffusion are found to be related to the solar cycle response in the Austral winter mesosphere wave‐mean flow dynamics. This work therefore concludes that the solar cycle affects lower thermospheric CO2 via modulations of the lower thermospheric circulation and eddy diffusion processes.