bluuebunny/crossref_metadata_2025_split huggingface dataset:
Information and communication technologies in primary healthcare facilities in Egypt
Authors: Farahat Taghreed M. , Hegazy Nagwa N. , Mowafy Maha 
Published: August 2017

BackgroundThe health sector has always relied on technologies. According to World Health Organization, they form the backbone of the services to prevent, diagnose, and treat illness and disease. It is increasingly viewed as the most promising tool for improving the overall quality, safety and efficiency of the health delivery system.Aim of the studyThis was to assess the current situation of information and communication technologies (ICTs) in primary healthcare in the terms of describing and classifying the existing work, identify gaps and exploring the personal experiences and the challenges of ICTs application in the primary healthcare.Subjects and methodsA mixed research method in the form of sequential explanatory design was applied. In the quantitative phase a cross-sectional study was conducted among 172 family physicians using a predesigned questionnaire. Followed by qualitative data collection among 35 participants through focused group discussions.ResultsNearly half of the physicians have ICTs in their work and they were trained on it. None of them developed a community-based research using ICTs technology. Training on ICTs showed a statistically significant difference regarding the availability and the type of ICTs present in the workplace (P&lt;0.05). Focused group discussion revealed that the majority of the participants believe that there is poor commitment of policymaker toward ICTs utilization in the primary care. Nearly 97% thinks that there is insufficient budget allocated for ICTs utilization in the workplace. Almost 88% of the participants demanded more incentives for ICTs users than non-user at the workplace.ConclusionsICTs resources are underutilized by health information professionals. Lack of funds, risk of instability of the electric supply and lack of incentives for ICTs users were the most common barriers to ICTs implementation thus a steady steps toward budget allocation and continuous training is needed.
The Planetary Nebulae Luminosity Function (PNLF): current perspectives
Authors: Méndez Roberto H. 
Published: August 2017

AbstractThis paper starts with a brief historical review about the PNLF and its use as a distance indicator. Then the PNLF distances are compared with Surface Brightness Fluctuations (SBF) distances and Tip of the Red Giant Branch (TRGB) distances. A Monte Carlo method to generate simulated PNLFs is described, leading to the last subject: recent progress in reproducing the expected maximum final mass in old stellar populations, a stellar astrophysics enigma that has been challenging us for quite some time.
Planetary Nebula Candidates Uncovered with the HASH Research Platform
Authors: Fragkou Vasiliki , Bojičić Ivan , Frew David , Parker Quentin 
Published: August 2017

AbstractA detailed examination of new high quality radio catalogues (e.g. Cornish) in combination with available mid-infrared (MIR) satellite imagery (e.g. Glimpse) has allowed us to find 70 new planetary nebula (PN) candidates based on existing knowledge of their typical colors and fluxes. To further examine the nature of these sources, multiple diagnostic tools have been applied to these candidates based on published data and on available imagery in the HASH (Hong Kong/ AAO/ Strasbourg Hα planetary nebula) research platform. Some candidates have previously-missed optical counterparts allowing for spectroscopic follow-up. Indeed, the single object spectroscopically observed so far has turned out to be a bona fide PN.
The Binary Central Star of Hf 38
Authors: Barker Helen 
Published: August 2017

AbstractDespite years of effort, the impact of central star binarity on planetary nebula formation and shaping remains unclear. This is hampered by the fact that detecting central star binarity is inherently difficult, and requires very precise observations. The fraction of planetary nebulae with binary central stars therefore remains elusive. This work presents initial results of central star analysis using data from the VST Hα Survey of the Southern Galactic Plane and Bulge (VPHAS+). The true central star of PN Hf 38 has been revealed, and it exhibits a 0.465±0.334 i band magnitude excess, indicative of a M0V companion.
Planet destruction and the shaping of planetary nebulae
Authors: Boyle L. A. , Redman M. P. 
Published: August 2017

AbstractThe shaping of PNe as a result of an interaction with a planet is a hypothesis that has been suggested for nearly two decades. However, exploring the idea observationally is challenging due to the lack of capabilities needed to detect any evidence of such a scenario. Nonetheless, we propose that the hypothesis can be indirectly tested via a combination of exoplanet formation and evolution theories, the star and planet formation histories of the galaxy and the tidal evolution of star-planet systems. We present a calculation of the fraction of planetary nebulae in the galaxy today which have undergone an interaction with a planet, concluding that a significant number of visible planetary nebulae may have been shaped by a planet.
Kinematic and chemical analysis of PNe in NGC 3109
Authors: Flores-Dúran Sheila N. , Peña Miriam , Ruiz María T. 
Published: August 2017

AbstractWe present high resolution spectroscopy obtained with MIKE-Magellan and MES OAN-SPM of a number of planetary nebulae (PNe) and H ii regions, distributed along the dwarf irregular galaxy NGC 3109 and compare their kinematical behavior with the one of H i data. We aim to determine if there is a kinematical connection among these objects. We also perform a revision of the chemical composition of PNe and H ii regions in this galaxy and discuss it in comparison with stellar evolution models.
The very fast evolution of Sakurai's object
Authors: Van de Steene G. C. , van Hoof P. A. M. , Kimeswenger S. , Zijlstra A. A. , Avison A. , Guzman-Ramirez L. , Hajduk M. , Herwig F. 
Published: August 2017

AbstractV4334 Sgr (a.k.a. Sakurai's object) is the central star of an old planetary nebula that underwent a very late thermal pulse a few years before its discovery in 1996. We have been monitoring the evolution of the optical emission line spectrum since 2001. The goal is to improve the evolutionary models by constraining them with the temporal evolution of the central star temperature. In addition the high resolution spectral observations obtained by X-shooter and ALMA show the temporal evolution of the different morphological components.
A homogeneous distance catalogue for Galactic RV Tauri objects
Authors: Vickers Shane B. , Frew David J. , Owers Matt S. , Parker Quentin A. , Bojičić Ivan S. 
Published: August 2017

AbstractA subset of Post-AGB (PAGB) objects are the highly luminous RV Tauri variables that show similarities to Type-II Cepheids. By using a sample of known RV Tauri stars from the Magellanic Clouds we are able to determine period luminosity relationships (PLRs) in various bands that have been used to determine the luminosities of their Galactic counterparts. We have gathered all available photometry in order to generate an SED for each object and determine the total integrated flux. This total flux combined with a calculated or inferred intrinsic luminosity leads to a distance (Vickers et al. 2015). This distance catalogue has allowed us to begin to constrain the physical parameters of this poorly understood evolutionary phase and to determine links between these physical characteristics as a function of their stellar population.
What can VLBI astrometry tell us about AR Sco?
Authors: Cui Lang , Yang Jun , Ma Hongli , Liu Jun , Chen Wen 
Published: August 2017

AbstractWe proposed to carry out high precision very long baseline interferometry (VLBI) observations of AR Sco, a pulsing white dwarf (WD) - M dwarf (MD) binary, to provide a direct distance measurement with the e-EVN (European VLBI Network) at 5 GHz. By the proposed parallax measurement on AR Sco, not only the precise distance will be determined, but also some physical parameters, such as the luminosity, the mass and the magnetic field will be significantly tightened accordingly, even the gravitational wave amplitude from this unique binary system can be tightly constrained. In addition, the EVN observations will allow us to answer that whether there is an extended emission structure associated with AR Sco, which will help us to explain the stable continuum radio emission observed during the pulse-off state.
Atomic Data and Neutron-Capture Element Abundances in Planetary Nebulae
Authors: Sterling N. C. 
Published: August 2017

AbstractNeutron(n)-capture elements are produced by s-process nucleosynthesis in low- and intermediate-mass AGB stars, and therefore can be enriched in planetary nebulae (PNe). In the last ten years, n-capture elements have been detected in more than 100 PNe in the Milky Way and nearby galaxies. In some objects, several different n-capture elements have been detected, providing valuable constraints to models of AGB nucleosynthesis and evolution. These detections have motivated theoretical and experimental investigations of the atomic data needed to derive accurate n-capture element abundances. In this review, I discuss the methods and results of these atomic data studies, and their application to abundance determinations in PNe.
Abundances of Iron-Group Elements in Planetary Nebulae and Consequences for Chemical Enrichment
Authors: Dinerstein Harriet L. , Geballe T. R. , Sterling N. C. 
Published: August 2017

AbstractWe have developed a method for determining elemental Fe-group abundances in planetary nebulae using an infrared emission line of Zn, the least refractory Fe-group species. Many planetary nebulae, particularly those of the Milky Way’s thick disk and bulge, display subsolar [Fe/H] (as inferred from Zn) although their abundances of α elements such as O, S, and Ar are nearly solar. We discuss the implications for determining enhancements of species synthesized by the progenitor star during the AGB (e.g.,s-process products), and for galactic chemical evolution in view of the metallicity dependence of AGB nucleosynthetic yields.
Binary interactions on the RGB: Dusty post-RGB stars
Authors: Kamath Devika , Van Winckel Hans , Wood Peter 
Published: August 2017

AbstractIt is widely accepted that binary interactions are responsible for the shaping of planetary nebula. However, these binary interactions and evolutionary channels are poorly understood. Our recent study revealed a newly discovered population of low-luminosity, low-metallicity, likely binaries in the Magellanic Clouds: dusty post-RGB stars. They are likely to have evolved off the RGB via binary interaction. In this paper we present preliminary results of the first radial velocity monitoring of the post-RGB stars in the Small Magellanic Cloud (SMC) and the implications on stellar (binary) evolution. We also investigate their link, if any, to the planetary nebulae systems.
Dust & Abundances of Metal-Poor Planetary Nebulae in the Galactic Anti-Center
Authors: Pagomenos George J. S. , Bernard-Salas Jeronimo , Sloan G. C. 
Published: August 2017

AbstractMuch of the new dust in the local ISM is produced in the last phases of stellar evolution of low- and intermediate-mass stars on the Asymptotic Giant Branch (AGB). Despite its importance, our knowledge of how dust properties depend on metallicity is limited. Studies of planetary nebulae in irregular galaxies in the Local Group (mostly focused on the LMC and SMC) have revealed a diverse spectral zoo and shown that low metallicity favours carbon-rich dust production by AGB stars. However, at ~1/3 and ~1/5 times the solar metallicity respectively, they provide two snapshots of dust composition at low metallicity, emphasising the need to investigate a region with a range of metallicity values. With its abundance gradient, the Milky Way fits this criterion and provides a good opportunity to observe the dust composition over a large metallicity range. In particular the Galactic anti-center, which is largely unexplored beyond galactocentric distances of 10 kpc, allows us to study the AGB dust a priori assumed to be metal-poor as well as exploring the extent of the Galactic abundance gradient. We analyse a Spitzer spectroscopic sample of 23 planetary nebulae towards the anti-center in order to understand how the metallicity gradient extends beyond 10 kpc from the Galactic center and to observe the dust composition in this region of our Galaxy. We find that the abundance gradients of Ne, S and Ar continue to distances of around 20 kpc (albeit with a large scatter) and the dust emission shows a carbon-rich chemistry similar to that in the Magellanic Clouds.
Hunting for binary central stars of planetary nebulae: exploiting archival data
Authors: Aller Alba , Vučković Maja , Lillo-Box Jorge , Miranda Luis F. , Jones David , Boffin Henri M. J. 
Published: August 2017

AbstractThe detection of new binary central stars of planetary nebulae is crucial to definitively determine the importance of binary interactions in the nebular morphology. In this context, we are working on a project that aims to increase the low number of binary central stars detected so far. For that, we are first analyzing public archival data in order to discover potential candidates of binary central stars. These candidates will be subsequently followed-up in order to confirm and characterize them. Here we present our ongoing search and some preliminary results.
Imaging the elusive H-poor gas in planetary nebulae with large abundance discrepancy factors
Authors: García-Rojas Jorge , Corradi Romano L. M. , Boffin Henri M. J. , Monteiro Hektor , Jones David , Wesson Roger , Cabrera-Lavers Antonio , Rodríguez-Gil Pablo 
Published: August 2017

AbstractThe discrepancy between abundances computed using optical recombination lines (ORLs) and collisionally excited lines (CELs) is a major, unresolved problem with significant implications for the determination of chemical abundances throughout the Universe. In planetary nebulae (PNe), the most common explanation for the discrepancy is that two different gas phases coexist: a hot component with standard metallicity, and a much colder plasma enhanced in heavy elements. This dual nature is not predicted by mass loss theories, and direct observational support for it is still weak. In this work, we present our recent findings that demonstrate that the largest abundance discrepancies are associated with close binary central stars. OSIRIS-GTC tunable filter imaging of the faint O ii ORLs and MUSE-VLT deep 2D spectrophotometry confirm that O ii ORL emission is more centrally concentrated than that of [Oiii] CELs and, therefore, that the abundance discrepancy may be closely linked to binary evolution.
The kinematical behavior of ORLs and CELs in PNe with [WC] central star
Authors: Peña Miriam , Ruiz-Escobedo Francisco , Rechy-García Jackeline , García-Rojas Jorge 
Published: August 2017

AbstractIn Planetary Nebulae (PNe) and HII regions ionic abundances can be derived by using collisionally excited lines (CELs) or recombination lines (ORLs). Such abundances do not coincide for the same ion and usually abundances from ORLs are larger than those from CELs by factors of 2 or larger. The origin of the discrepancy, known as the Abundance Discrepancy Factor is an open problem in astrophysics of gaseous nebulae. It has been attributed to temperature fluctuations in the plasma, tiny metal-rich inclusions embedded in the H-rich plasma, gas inhomogeneities or other processes. In this work we analyze the kinematical behavior of CELs and ORLs in two PNe ionized by [WC] stars, finding that kinematics of ORLS is incompatible with the kinematics of CELs. In particular the expansion velocities from CELs and ORLs for the same ion are different, indicating that ORLs seem to be produced in zones nearer the central star than CELs. This is in agreement with results found by other authors for individual PNe.
Magnetic fields in PNe and other evolved low-mass and intermediate-mass stars
Authors: Sabin Laurence , Zhang Qizhou , Wade Gregg A. , Lèbre Agnès , Vázquez Roberto 
Published: August 2017

AbstractMagnetic fields are likely to be an efficient mechanism which can affect evolved intermediate mass stars (i.e. post-AGB stars and planetary nebulae) in different ways such as via the shaping of their envelope. However, observational probes for the presence of those fields are still scarce. I will present a summary of the works, including those from our group, on the detection and measurement of magnetic fields in various evolved objects.
Modelling dust production in AGB stars
Authors: Dell’Agli Flavia 
Published: August 2017

AbstractAsymptotic giant branch (AGB) stars are among the most important gas and dust polluters of the Universe. The latest AGB evolutionary models take into account dust production in the circumstellar envelope of these stars, starting from a detailed computation of the main physical processes and chemical surface variations occurring in this evolutionary phase. Following the formation and growth of dust particles, they provide the unique possibility of interpreting the AGB population observed in resolved galaxies. The first application was for the Spitzer observations of dusty AGBs in the Magellanic Clouds, characterising carbon-rich and oxygen-rich stars in terms of initial mass, epoch of star formation, evolutionary time on the AGB and dust contribution. The same set of models are able to interpret the CNO surface abundances observed for the PNe of the same galaxies.
The history of the Galactic bulge
Authors: Zijlstra A. A. , Gesicki K. , Bertolami M. M. Miller 
Published: August 2017

AbstractPlanetary nebulae form in stellar populations with ages from 1 to 10 Gyr, and can be used to trace their star formation histories. Here we apply this to the Galactic bulge, where there are indications both for an old origin and for younger stars. We use new stellar models, which have significant different evolutionary speeds during the post-AGB phase. We apply these new models to a sample of 32 planetary nebulae with HST imaging and VLT spectroscopy. The results show evidence for an old starburst, followed by continuous star formation until at least 2Gyr ago. This agrees very well with recent analysis of colour-magnitude diagrams of the bulge. We show that the new models can also explain the [OIII] luminosity functions, and predict the uniform luminosity cut-off both in spiral galaxies and old elliptical galaxies.
Photoionization models of Planetary Nebulae
Authors: Morisset Christophe 
Published: August 2017

AbstractThe understanding of astronomical nebulae is based on observational data (images, spectra, 3D data-cubes) and theoretical models. In this review, I present my very biased view on photoionization modeling of planetary nebulae, focusing on 1D multi-component models, on 3D models and on big database of models.
Stellar yields and abundances: new directions from planetary nebulae
Authors: Lugaro Maria , Karakas Amanda I. , Pignatari Marco , Doherty Carolyn L. 
Published: August 2017

AbstractPlanetary nebulae retain the signature of the nucleosynthesis and mixing events that occurred during the previous AGB phase. Observational signatures complement observations of AGB and post-AGB stars and their binary companions. The abundances of the elements heavier than iron such as Kr and Xe in planetary nebulae can be used to complement abundances of Sr/Y/Zr and Ba/La/Ce in AGB stars, respectively, to determine the operation of theslowneutron-capture process (thesprocess) in AGB stars. Additionally, observations of the Rb abundance in Type I planetary nebulae may allow us to infer the initial mass of the central star. Several noble gas components present in meteoritic stardust silicon carbide (SiC) grains are associated with implantation into the dust grains in the high-energy environment connected to the fast winds from the central stars during the planetary nebulae phase.
XSHOOTER spectroscopy of the enigmatic PN Lin49 in the SMC
Authors: Otsuka Masaaki , Kemper Francisca , Leal-Ferreira Marcelo L. , Aleman Isabel , Bernard-Salas Jeronimo , Cami Jan , Ochsendorf Bram B. , Peeters Els , Scicluna Peter 
Published: August 2017

AbstractWe performed a detailed spectroscopic analysis of the fullerene C60-containing planetary nebula (PN) Lin49 in the Small Magellanic Cloud (SMC). Lin49 is a C-rich and metal-deficient PN (Z~0.0006) and its nebular abundances are in agreement with the AGB model for the initially 1.25 M⊙ stars with the metallicity Z = 0.001. By stellar absorption fitting with TLUSTY, we derived stellar abundances, effective temperature, and surface gravity. We constructed the photoionization model with CLOUDY in order to investigate physical conditions of Lin49. The model with the 0.005-0.1 μm radius graphite and a constant hydrogen density shell could not fit the ~1-5 μm spectral energy distribution (SED) owing to the strong near-IR excess. We propose that the near-IR excess indicates (1) the presence of extremely small carbon molecules or (2) the presence of high-density structure surrounding the central star.
New models for the evolution of central stars of planetary nebulae: Faster and Brighter
Authors: Bertolami Marcelo M. Miller 
Published: August 2017

AbstractThe post-asymptotic giant branch (AGB) phase is arguably one of the least understood phases of the evolution of low- and intermediate- mass stars. The recent post-AGB evolutionary sequences computed by Miller Bertolami (2016) are at least three to ten times faster than those previously published by Vassiliadis & Wood (1994) and Blöcker (1995) which have been used in a large number of studies. This is true for the whole mass and metallicity range. The new models are also ~0.1–0.3 dex brighter than the previous models with similar remnant masses. In this short article we comment on the main reasons behind these differences, and discuss possible implications for other studies of post-AGB stars or planetary nebulae.
The population of planetary nebulae near the Galactic Centre: chemical abundances
Authors: Mollá M. , Cavichia O. , Costa R. D. D. , Maciel W. J. 
Published: August 2017

AbstractIn this work, we report physical parameters and abundances derived for a sample of 15 high extinction planetary nebulae located in the inner 2° of the Galactic bulge, based on low dispersion spectroscopy secured at the SOAR telescope using the Goodman spectrograph. The new data allow us to extend our database including older, weaker objects that are at the faint end of the planetary nebulae luminosity function. The data provide chemical compositions for PNe located in this region of the bulge to explore the chemical enrichment history of the central region of the Galactic bulge. The results show that the abundances of our sample are skewed to higher metallicities than previous data in the outer regions of the bulge. This can indicate a faster chemical enrichment taking place at the Galactic centre.
3D Hydrodynamical models of the planetary nebulae M 1-32 and M 3-15
Authors: Rechy-García Jackeline S. , Velázquez Pablo F. , Peña Miriam , Raga Alejandro C. 
Published: August 2017

AbstractHigh-resolution, long-slit spectroscopic observations of two planetary nebulae, M1-32 and M3-15 are presented. The observations were obtained with the 2.1-m telescope at the OAN-SPM, and MES spectrograph. M1-32 shows wide wings on the base of its emission lines and M3-15 has two very faint high-velocity knots. To model both PNe we built a 3D model consisting in a jet interacting with an equatorially concentrated slow wind, emulating the presence of a dense torus, by using the hydrodynamical code Yguazú. The synthetic position-velocity (PV) diagrams obtained from our models reproduce well the observed PV diagrams.