bluuebunny/crossref_metadata_2025_split huggingface dataset:
Planetary nebulae and the chemical evolution of the galactic bulge: New abundances of older objects
Authors: Cavichia Oscar , Costa Roberto D. D. , Mollá Mercedes , Maciel Walter J. 
Published: August 2012

AbstractIn view of their nature, planetary nebulae have very short lifetimes, and the chemical abundances derived so far have a natural bias favoring younger objects. In this work, we report physical parameters and abundances for a sample of old PNe located in 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 nebula luminosity function (PNLF). The results show that the abundances of our sample are lower than those from our previous work. Additionally, the average abundances of the galactic bulge do not follow the observed trend of the radial abundance gradient in the disk. These results are in agreement with a chemical evolution model for the Galaxy recently developed by our group.
Photoionization modeling of the Galactic planetary nebulae Abell 39 and NGC 7027
Authors: Danehkar Ashkbiz , Frew David J. , Parker Quentin A. , De Marco Orsola 
Published: August 2012

AbstractWe estimate distances to the spherical planetary nebula Abell 39 and the bipolar planetary nebula NGC 7027 by interpolating from a wide grid of photoionization models using the 3-D code, MOCASSIN. We find preliminary distances of 1.5 kpc and 0.9 kpc respectively, with uncertainties of about 30%.
C/O abundance ratios and dust features in galactic planetary nebulae
Authors: Delgado-Inglada Gloria , Rodríguez Mónica 
Published: August 2012

AbstractThe iron depletion factors found in Galactic planetary nebulae (PNe) span over two orders of magnitude, suggesting that there are differences in the grain formation and destruction processes from object to object. We explore here the relation between the iron depletions, the infrared dust features, and the C/O abundance ratios in a sample of Galactic PNe. We find that those objects with C/O<1 show a trend of increasing depletions for higher values of C/O, whereas PNe with C/O>1 break the trend and cover all the range of depletions. Most of the PNe with C/O<1 show silicate features, but several PNe with C-rich features have C/O<1, probably reflecting the uncertainties associated with the derivation of C/O. PAHs are distributed over the entire range of iron depletions and C/O values.
Kn 26: a textbook case hourglass planetary nebula with a twist
Authors: Guerrero Martín A. , Vázquez Roberto , Miranda Luis F. , Ramos-Larios Gerardo 
Published: August 2012

AbstractKn 26 is a recently identified planetary nebula (PN). To confirm its nature and study its spatio-kinematical structure, we have obtained high spatial-resolution optical and near-IR narrowband images, high-dispersion long-slit echelle spectra, and intermediate-resolution spectroscopic observations. The new data confirm the PN nature of Kn 26 and reveal features typical of bipolar PNe: hourglass morphology, H2 emission, and nitrogen enrichment. A detailed analysis of its morphology and kinematics, however, suggests the presence of one additional pair of bipolar lobes that would make Kn 26 a new member of the class of quadrupolar PNe.
GLMP 160 – the first [WR] star in a binary
Authors: Hajduk Marcin , van Hoof Peter A. M. , Zijlstra Albert A. 
Published: August 2012

AbstractWe discuss the results of the search for [WR] central stars in binary systems. GLMP 160 is the first [WR] central star in a binary system known. We analyze photometry, spectroscopy and imaging of this system.
Planetary nebula abundance determinations: A view from 1D-RHD simulations
Authors: Jacob Ralf , Sandin Christer , Schönberner Detlef , Steffen Matthias 
Published: August 2012

AbstractIn the last years (metallicity-dependent) radiation-hydrodynamics simulations have become a powerful tool to understand the formation and evolution of PNe in terms of simple morphologies and kinematics. Contrary to photoionization models, with their ad-hoc assumptions on structure and physics, the RHD models are self-consistent with respect to their density distribution, velocity field, chemical composition, and stellar evolution. We use our models as simple proxies for real PNe and investigate the reliability of common abundance determination methods, which are based on either plasma diagnostics or static photoionization (PI) models.
On the internal kinematics of PNe
Authors: Jacob Ralf , Schönberner Detlef , Lehmann Holger , Zwanzig Alena , Sandin Christer , Steffen Matthias 
Published: August 2012

AbstractOur sample of round/elliptical double-shell PNe around central stars (CSs) with H-rich surface chemistry covers all evolutionary phases across the HRD. By means of high-resolution and high-S/N spectra we determine bulk matter velocities of the inner wind-driven rims and the maximum (= post-shock) gas velocities of the surrounding thermally expanding shells. Studying the details of the internal kinematics allows a look at processes of PN formation and at PN expansion history helping, for instance, to determine expansion distances.
New kinematic distance scale for the Galactic planetary nebulae
Authors: Kholtygin Alexander F. , Nikiforov Igor' I. , Akimkin Vitalii V. 
Published: August 2012

AbstractWe analyze the kinematics of disk planetary nebulae (PNe) to derive the formal Galactic center distance, R0, for three catalogues of PNe distances. Then we correct the catalogues' distance scales renormalizing the PNe distances by the ratios of formal R0 values to a best modern value of R0 =7.9 kpc. The created new catalogue of disk's PNe distances was found to be in a good agreement with distances by Stanghellini et al. (2008). Our catalogue of PNe distances was used to recalibrate the statistical distance scale for all Galactic PNe.
Further exploration of Galactic disk abundance gradients
Authors: Milingo Jackie B. , Henry Richard B. C. , Kwitter Karen B. , Balick Bruce 
Published: August 2012

AbstractWe examine the abundance gradient in the Milky Way disk via homogeneously determined data for 124 Galactic planetary nebulae (PNe). We present recent results from a detailed regression analysis of the O gradient. With O, Ne, S, Cl, and Ar available and a range of galactocentric distance (Rg) from 0.9 to 21 kpc, we present additional exploration of the disk radial gradient by statistically analyzing a series of short segments of increasing average Rg.
Morphological and kinematical analysis of the planetary nebula Hu 1-2 and its irradiated bow-shocks
Authors: Miranda Luis F. , Blanco Mónica , Guerrero Martín A. , Riera Angels 
Published: August 2012

AbstractWe present narrow-band optical and near-IR images, and high-resolution long-slit spectra of the planetary nebula Hu 1-2 that allow us to make a detailed description of its unusual morphology and internal kinematics. The data also reveal that the ansae of Hu 1-2 probably represent bow-shocks associated to high velocity outflows that are irradiated from the central star.
A 3D view of the planetary nebula NGC 40
Authors: Monteiro Hektor , Falceta-Gonçalves Diego 
Published: August 2012

AbstractWe present the results of a study of the planetary nebula NGC 40 with the use of the 3-D photoionization code Mocassin constrained by observational data of different types. The modeling process allows us to derive the three-dimensional nebular structure, physical and chemical characteristics and ionizing star parameters of the object by simultaneously fitting the integrated line intensities, the temperature map, density map, and the observed morphologies in different emission lines. For this particular case we combined hydrodynamical simulations with the photoionization scheme in order to obtain a self-consistent distribution of density and velocity of the nebular material. Finally, using theoretical evolutionary tracks of intermediate and low mass stars, we estimate the mass and age of the central star of NGC 40 as being 0.57 M⊙ and 5810 yr, respectively. The distance obtained from the fitting procedure was 1150 ± 170 pc.
Mapping the physical and chemical properties of the planetary nebula NGC 3242
Authors: Monteiro Hektor , Gonçalves Denise , Leal-Ferreira Marcelo , Corradi Romano , Sánchez Sebastian 
Published: August 2012

AbstractWe present optical integral field spectroscopy analysis of the main components, with the exception of the halo, as well as of the detected small-scale structures of the planetary nebulae NGC 3242. The observations were obtained with the VIMOS instrument attached to VLT-UT3. Spatially resolved maps of the electronic density (Ne), temperatures (Te) and chemical abundances, i.e., in a pixel to pixel fashion of the small and large-scales structures of this planetary nebula are determined in this work. These diagnostic and abundance maps represent important constraints for future detailed three dimensional photoionization modeling of the nebula, as well as providing important information on biases introduced by traditional slit observations.
Morphokinematic properties of the 21 micron source IRAS 22272+5435
Authors: Nakashima Jun-ichi , Kwok Sun , Yung Bosco H. K. , Zhang Yong , Koning Nico , Volgenau Nikolaus 
Published: August 2012

AbstractWe obtained a high-resolution CO map of IRAS 22272+5435 in the CO J = 2–1 line using CARMA. The target exhibits a second biggest angular size of the circumstellar molecular envelope among known 21 μm sources. In the preliminary results, we found that the CO properties of IRAS 22272+5435 is clearly different from those of IRAS 07134+1005, which is another well-investigated 21 μm source. For example, elongations seen in the mid-infrared and CO images are extended in mutually perpendicular directions, although in case of IRAS 07134+1005 the CO feature coincides well with the mid-infrared structure.
NGC 6302: high-ionization permitted lines. Applying X-SSN synthesis to VLT-UVES spectra
Authors: Péquignot Daniel , Morisset Christophe , Casassus Simon 
Published: August 2012

AbstractA preliminary VLT-UVES spectrum of NGC 6302 (Casassus et al. 2002, MN), which hosts one of the hottest PN nuclei known (Teff ~ 220000 K; Wright et al. 2011, MN), has been recently analysed by means of X-SSN, a spectrum synthesis code for nebulae (Morisset and Péquignot). Permitted recombination lines from highly-ionized species are detected/identified for the first time in a PN, and some of them probably for the first time in (astro)physics. The need for a homogeneous, high signal-to-noise UVES spectrum for NGC 6302 is advocated.
The radio continuum from a planetary nebula as a mirror of the central star evolution
Authors: Sharova Olga I. 
Published: August 2012

AbstractIn the frame of ISW model the rates of the evolutionary changes of the flux density and the critical frequency in radio continuum spectrum have been calculated in dependence on the kinematic age of a planetary nebula. The time changes of the instantaneous radio spectra of IC 418 and NGC 6369 do not contradict accounts.
UV-NIR spectra of two planetary nebulae with X-Shooter
Authors: Szyszka Cezary , Walsh Jeremy R. , Zijlstra Albert A. 
Published: August 2012

AbstractThe ESO VLT spectrograph X-shooter is currently the only one capable of observing the range from 330 nm up to 2.5 μm in a single shot. X-shooter is very suitable for study of the many diagnostic emission lines in PN providing a uniform flux scale at medium resolution over a large instantaneous wavelength range. Spectroscopy of two contrasting PNe, NGC 6302 and M 2-9, were observed and methods explored for identification of the many fitted emission lines.
Radial density profiles of PNe halos from numerical models of mass-loss history
Authors: Verbena Juan-Luis , Schröder Klaus-Peter , Wachter Astrid 
Published: August 2012

AbstractWe review the stellar mass loss of red giants and tip-AGB objects analizing the variation in the outflow velocity for different mass models (Wachter et al. 2002). We approach the superwind problem and see the evolution of tip-AGB stars via previously made mass-loss histories that are consistent with the Weidemann initial-final mass relationship (for carbon-rich stars). Finally density profiles are produced from these mass-loss histories, and the corresponding line-of-sight integration is compared with observational data (Phillips et al. 2009). We note the resemblance between the results obtained with our models and the observational data. We are thus able to reproduce the general trends of the emission from simple models (see Verbena et al. 2011).
Signatures of pulsations and mass loss in the spectra of post-AGB stars
Authors: Začs Laimons , Sperauskas Julius , Laure Aija , Smirnova Olesja 
Published: August 2012

AbstractThe results of high-resolution spectroscopy and radial velocity monitoringa are presented for selected post-AGB candidate stars. Time series of high-resolution spectra for HD235858 shows spliting of low-excitation atomic lines and significant changes in the intensity of C2 and CN lines originated in the extended atmosphere significantly affected by pulsations and outflow. Mass ejection was confirmed for cool R CrB candidate stars DY Per, V1983 Cyg, and V2074 Cyg.
Planetary nebulae detected in the Spitzer Space Telescope GLIMPSE 3D Legacy Survey
Authors: Zhang Yong , Kwok Sun , Hsia Chih-Hao , Nakashima Jun-ichi , Koning Nico 
Published: August 2012

AbstractDue to interstellar extinction, optical census of Galactic planetary nebulae (PNs) is highly incomplete, and some compact H ii regions might have been mis-classified as PNs. The problem is particularly severe in the Galactic plane where the extinction in the optical is significant and hampers the detections of PNs. Unlike optical observations, infrared (IR) observations are hardly affected by interstellar extinction, and provide a good opportunity to study highly obscured PNs. In this study, we use the data from the Spitzer Legacy Infrared Mid-Plane Survey Extraordinaire 3D (GLIMPSE 3D) to investigate the mid-infrared (MIR) properties of PNs and PN candidates.
Sizing up metatranscriptomics
Authors: Moran Mary Ann , Satinsky Brandon , Gifford Scott M , Luo Haiwei , Rivers Adam , Chan Leong-Keat , Meng Jun , Durham Bryndan P , Shen Chen , Varaljay Vanessa A , Smith Christa B , Yager Patricia L , Hopkinson Brian M 
Published: August 2012

Abstract
A typical marine bacterial cell in coastal seawater contains only ∼200 molecules of mRNA, each of which lasts only a few minutes before being degraded. Such a surprisingly small and dynamic cellular mRNA reservoir has important implications for understanding the bacterium’s responses to environmental signals, as well as for our ability to measure those responses. In this perspective, we review the available data on transcript dynamics in environmental bacteria, and then consider the consequences of a small and transient mRNA inventory for functional metagenomic studies of microbial communities.
TLR2 and TLR4 activation induces p38 MAPK‐dependent phosphorylation of S6 kinase 1 in C2C12 myotubes
Authors: Zbinden‐Foncea Hermann , Deldicque Louise , Pierre Nicolas , Francaux Marc , Raymackers Jean‐Marc 
Published: August 2012

AbstractToll‐like receptors 2 (TLR2) and 4 (TLR4) are present in the plasma membrane of skeletal muscle cells where their functions remain incompletely resolved. They can bind various extracellular ligands, such as FSL‐1, lipopolysaccharide (LPS) and/or palmitic acid (PA). We have investigated the link between PA, TLR2/4 and ribosomal S6 kinase 1 (S6K1) in C2C12 myotubes. Incubation with agonists of either TLR2 or TLR4, and with a high concentration of PA, increased S6K1 phosphorylation. Canonical upstream kinases of S6K1, protein kinase B (PKB) and mammalian target of rapamycin complex 1 (mTORC1), were regulated in the opposite way by PA, indicating that these kinases were probably not involved. By using the SB202190 inhibitor, p38 MAPK (mitogen‐activated protein kinase) was found to be a key mediator of PA‐induced phosphorylation of S6K1. Downregulation of either tlr2 or tlr4 gene expression by small interfering RNAs prevented the activation of both p38 MAPK and S6K1 by FSL‐1, LPS or PA. Thus TLR2 and TLR4 agonists can increase the level of S6K1 phosphorylation in a p38 MAPK‐dependent way in C2C12 myotubes. As PA induced the same intracellular signalling, a novel atypical pathway for PA is induced at the cellular membrane level and results in a higher phosphorylation state of S6K1.
Diagnosing postural tachycardia syndrome: comparison of tilt testing compared with standing haemodynamics
Authors: Plash Walker B. , Diedrich André , Biaggioni Italo , Garland Emily M. , Paranjape Sachin Y. , Black Bonnie K. , Dupont William D. , Raj Satish R. 
Published: August 2012

POTS (postural tachycardia syndrome) is characterized by an increased heart rate (ΔHR) of ≥30 bpm (beats/min) with symptoms related to upright posture. Active stand (STAND) and passive head-up tilt (TILT) produce different physiological responses. We hypothesized these different responses would affect the ability of individuals to achieve the POTS HR increase criterion. Patients with POTS (n=15) and healthy controls (n=15) underwent 30 min of tilt and stand testing. ΔHR values were analysed at 5 min intervals. ROC (receiver operating characteristic) analysis was performed to determine optimal cut point values of ΔHR for both tilt and stand. Tilt produced larger ΔHR than stand for all 5 min intervals from 5 min (38±3 bpm compared with 33±3 bpm; P=0.03) to 30 min (51±3 bpm compared with 38±3 bpm; P&lt;0.001). Sn (sensitivity) of the 30 bpm criterion was similar for all tests (TILT10=93%, STAND10=87%, TILT30=100%, and STAND30=93%). Sp (specificity) of the 30 bpm criterion was less at both 10 and 30 min for tilt (TILT10=40%, TILT30=20%) than stand (STAND10=67%, STAND30=53%). The optimal ΔHR to discriminate POTS at 10 min were 38 bpm (TILT) and 29 bpm (STAND), and at 30 min were 47 bpm (TILT) and 34 bpm (STAND). Orthostatic tachycardia was greater for tilt (with lower Sp for POTS diagnosis) than stand at 10 and 30 min. The 30 bpm ΔHR criterion is not suitable for 30 min tilt. Diagnosis of POTS should consider orthostatic intolerance criteria and not be based solely on orthostatic tachycardia regardless of test used.
A Remote‐Sensing, GIS‐Based Approach to Identify, Characterize, and Model Spawning Habitat for Fall‐Run Chum Salmon in a Sub‐Arctic, Glacially Fed River
Authors: Wirth Lisa , Rosenberger Amanda , Prakash Anupma , Gens Rudiger , Margraf F. Joseph , Hamazaki Toshihide 
Published: August 2012

AbstractAt northern limits of a species’ distribution, fish habitat requirements are often linked to thermal preferences, and the presence of overwintering habitat. However, logistical challenges and hydrologic processes typical of glacial systems could compromize the identification of these habitats, particularly in large river environments. Our goal was to identify and characterize spawning habitat for fall‐run chum salmon Oncorhynchus keta and model habitat selection from spatial distributions of tagged individuals in the Tanana River, Alaska using an approach that combined ground surveys with remote sensing. Models included braiding, sinuosity, ice‐free water surface area (indicating groundwater influence), and persistent ice‐free water (i.e., consistent presence of ice‐free water for a 12‐year period according to satellite imagery). Candidate models containing persistent ice‐free water were selected as most likely, highlighting the utility of remote sensing for monitoring and identifying salmon habitat in remote areas. A combination of ground and remote surveys revealed spatial and temporal thermal characteristics of these habitats that could have strong biological implications. Persistent ice‐free sites identified using synthetic aperture radar appear to serve as core areas for spawning fall chum salmon, and the importance of stability through time suggests a legacy of successful reproductive effort for this homing species. These features would not be captured with a one‐visit traditional survey but rather required remote‐sensing monitoring of the sites through time.
Agricultural Insurance in Developed Countries: Where Have We Been and Where Are We Going?
Authors: Smith Vincent H. , Glauber Joseph W. 
Published: August 2012

AbstractAgricultural insurance in developed countries originates in named peril products that were originally offered by private companies approximately two hundred years ago, first in Europe and then in the United States. Today, many agricultural insurance products are offered, most of them heavily subsidized by governments. In the context of developed economies, this article examines the evolution of agricultural insurance products, the economics of the demand and supply sides of agricultural insurance markets, and the economic welfare, political economy, and trade relation implications of private and public agricultural insurance in developed countries.
MASSIVE EXUDATIVE RETINAL DETACHMENT AFTER PHOTODYNAMIC THERAPY FOR PERIPHERAL RETINAL CAPILLARY HEMANGIOMA
Authors: Goto So , Oshima Yusuke , Tsujikawa Motokazu , Nishida Kohji 
Published: August 2012

Purpose:
To report a case requiring emergency surgical intervention to treat a progressive massive retinal detachment after photodynamic therapy for a peripheral retinal capillary hemangioma associated with von Hippel-Lindau disease.

Methods:
A 38-year-old woman with von Hippel-Lindau disease had a peripheral retinal capillary hemangioma in the left eye. At the initial visit, the best-corrected visual acuity was 20/250 in the left eye. Photodynamic therapy was applied to treat the hemangioma. After 1 day, a massive retinal detachment and vitreous hemorrhage occurred. Three days after photodynamic therapy, vitrectomy was performed to treat the retinal detachment, which progressed with visual deterioration to hand motions.

Results:
A diagnosis of exudative retinal detachment was made because no retinal breaks were identified. The retina was reattached with external drainage and gas tamponade. One month postoperatively, the best-corrected visual acuity recovered to 20/100 in the left eye, and the vascular activity of the hemangioma stabilized.

Conclusion:
Photodynamic therapy monotherapy to treat retinal capillary hemangioma might result in a massive exudative retinal detachment requiring surgery.