bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low dispersion spectroscopy of point-symmetric planetary nebulae
Authors: Olguín Lorenzo , Vázquez Roberto , Contreras María E. , Sabin Laurence , Guillén Pedro F. 
Published: August 2012

AbstractWe present an observational study of three oint-ymmetric lanetary ebulae (PS-PNe): PC 19, He 2-429, and He 1-1, whose kinematics has been previously reported in the literature. The study includes an analysis of physical conditions and chemical abundances. We found that the abundances of He 2-429 and He 1-1 correspond to a Peimbert Type I PNe while those of PC 19 are in good agreement with a Type IV PN. Kinematic evidence derived from proper motion measurement support PC 19 classification and suggest that the progenitor star was a low-mass low-metallicity member of the galactic halo population.
He I temperatures in planetary nebulae
Authors: Peimbert Antonio , Peimbert Manuel 
Published: August 2012

AbstractIt is well established that PNe are not thermally homogeneous, beyond what chemically homogeneous photoionization models predict. To discriminate between the different scenarios proposed in the literature, we have determined the temperature based on He I lines for a dozen PNe. We compare these determinations with those derived from the Balmer continua. We find that the He I temperatures agree with the Balmer temperatures and that both are lower than those derived from CELs; suggesting that most PNe are chemically homogeneous.
Filling factor and temperature variations in planetary nebulae
Authors: Peimbert Manuel , Peimbert Antonio 
Published: August 2012

AbstractWe have found a strong correlation between small filling factors and large t2 values in planetary nebulae. We have also found that in general the filling factor for Type I PNe is smaller than for Type II PNe. These results imply that the abundance correction due to temperature inhomogeneities in general is larger for Type I PNe than for Type II PNe. This difference permits to reproduce the expected abundance difference between PNe of Type I and II predicted by Galactic chemical evolution models.
H2O maser polarization of the water fountains IRAS 15445–5449 and IRAS 18043–2116
Authors: Pérez-Sánchez Andrés F. , Vlemmings Wouter H. T. , Chapman Jessica M. 
Published: August 2012

AbstractWe present the morphology and linear polarization of the 22-GHz H2O masers in the high-velocity outflow of two post-AGB sources, d46 (IRAS 15445–5449) and b292 (IRAS 18043–2116). The observations were performed using The Australia Telescope Compact Array. Different levels of saturated maser emission have been detected for both sources. We also present the mid-infrared image of d46 overlaid with the distribution of the maser features that we have observed in the red-shifted lobe of the bipolar structure. The relative position of the observed masers and a previous radio continuum observation suggests that the continnum is produced along the blue-shifted lobe of the jet. It is likely due to synchrontron radiation, implying the presence of a strong magnetic field in the jet. The fractional polarization levels measured for the maser features of d46 indicate that the polarization vectors are tracing the poloidal component of the magnetic field in the emitting region. For the H2O masers of b292 we have measured low levels of fractional linear polarization. The linear polarization in the H2O maser region of this source likely indicates a dominant toroidal or poloidal magnetic field component.
Nebula around R Corona Borealis
Authors: Rao N. Kameswara , Lambert David L. 
Published: August 2012

AbstractThe star R Corona Borealis (R CrB) shows forbidden lines of [O II], [N II], and [S II] during the deep minimum when the star is fainter by about 8 to 9 magnitudes from normal brightness, suggesting the presence of nebular material around it. We present low and high spectral resolution observations of these lines during the ongoing deep minimum of R CrB, which started in July 2007. These emission lines show double peaks with a separation of about 170 km/s. The line ratios of [S II] and [O II] suggest an electron density of about 100 cm−3. We discuss the physical conditions and possible origins of this low density gas. These forbidden lines have also been seen in other R Coronae Borealis stars during their deep light minima and this is a general characteristic of these stars, which might have some relevance to their origins.
Spectral analysis of the O(He)-type central stars of the planetary nebulae K 1-27 and LoTr 4
Authors: Reindl Nicole , Ringat Ellen , Rauch Thomas , Werner Klaus , Kruk Jeffrey. W. 
Published: August 2012

AbstractThe four known O(He) stars are the only amongst the hottest post-AGB stars whose atmospheres are composed of almost pure helium. Thus, their evolution deviates from the hydrogen-deficient post-AGB evolutionary sequence of carbon-dominated stars like e.g. PG 1159 stars. The origin of the O(He) stars is still not explained. They might be either post-early AGB stars or the progeny of R Coronae Borealis stars. We present preliminary results of a non-LTE spectral analysis based on FUSE and HST/COS observations.
The multi-polar planetary nebula NGC 5189
Authors: Sabin Laurence , Vázquez Roberto , Lopéz Jose A. , García-Diaz Maria-Teresa 
Published: August 2012

AbstractNGC 5189 is a particularly interesting planetary nebula (PN) displaying multiple bipolar structures. This type of morphology is generally attributed to multiple mass loss events believed to originate from a precessing central source. In order to better understand this, once dubbed chaotic PN, we have investigated optical imaging combined with low- and high- resolution spectroscopic data to dissect its components. The imaging reveals three and possibly four well defined bipolar lobes showing a misalignment with respect to the central torus, although sharing the same geometric center. The high nitrogen levels detected in the elongated filaments/condensations surrounding the nebula and at the torus location highlight the presence of low ionization structures as well as the possible occurrence of shocks in the areas perturbed by large dynamical motions. Finally the kinematical study indicates moderate expansion velocities (35 km.s−1 in the western lobe, 33 km.s−1 in the central region and 44 km.s−1 in the eastern lobe). We also notice the asymmetry of the [NII] distribution and the velocities inside NGC 5189 between its North-West and South-East components.
New planetary nebulae with ISM interaction discovered with IPHAS
Authors: Sabin Laurence , Corradi Romano L. M. , Parker Quentin , Mampaso Antonio , Zijlstra Albert 
Published: August 2012

AbstractThe low surface brightness usually associated with nebulae mixing with the ISM has long been a substantial obstacle in the observation and statistical study of these interactions. Thanks to the detection capability of the INT Photometric H-alpha Survey (IPHAS), in terms of sensitivity and imaging resolution, we were able to detect and select tens of examples of candidate Planetary Nebulae apparently at different stages of interaction with the interstellar medium (PNe-ISM hereafter) following the Wareing et al. (2007) classification. A spectroscopic investigation was conducted with the San Pedro Martir 2.1m telescope (SPM) in Mexico and we present the first results involving a proper classification and analysis of our candidates. The main difficulty is visually separating PNe-ISM from other faint asymmetric nebulosities such as old HII regions, SNRs and general diffuse H-alpha structures. This investigation is a first step in a more comprehensive study of PNe-ISM as more candidates are uncovered by the IPHAS team.
The role of heat conduction to the formation of [WC]-type planetary nebulae
Authors: Sandin Christer , Steffen Matthias , Jacob Ralf , Schönberner Detlef , Rühling Ute , Hamann Wolf-Rainer , Todt Helge 
Published: August 2012

AbstractX-ray observations of young Planetary Nebulæ (PNe) have revealed diffuse emission in extended regions around both H-rich and H-deficient central stars. In order to also reproduce physical properties of H-deficient objects, we have, at first, extended our time-dependent radiation-hydrodynamic models with heat conduction for such conditions. Here we present some of the important physical concepts, which determine how and when a hot wind-blown bubble forms. In this study we have had to consider the, largely unknown, evolution of the CSPN, the slow (AGB) wind, the fast hot-CSPN wind, and the chemical composition. The main conclusion of our work is that heat conduction is needed to explain X-ray properties of wind-blown bubbles also in H-deficient objects.
A detailed look at chemical abundances in the Magellanic Clouds
Authors: Shaw Richard A. , Lee Ting-Hui , Stanghellini Letizia , Davies James E. , García-Hernández D. Anibal , García-Lario Pedro , Perea-Calderón Jose-Vicente , Villaver Eva , Manchado Arturo , Palen Stacy , Balick Bruce 
Published: August 2012

AbstractWe determine elemental abundances of He, N, O, Ne, S, and Ar in Magellanic Cloud planetary nebulae (PNe) using direct methods and a large set of observed ions, minimizing the need for ionization correction factors. In contrast to prior studies, we find a clear separation between Type I and non-Type I PNe in these low-metallicity environments, and no evidence that the O-N nucleosynthesis cycle is active in low-mass progenitors. We find that the S/O abundance ratio is anomalously low compared to H ii regions, confirming the “sulfur anomaly” found for Galactic PNe. We also found that Ne/O is elevated in some cases, raising the possibility that Ne yields in low-mass AGB stars may be enhanced at low metallicity.
Radiative transfer model of the dust structures of CRL 2688
Authors: Vinković Dejan , Balick Bruce 
Published: August 2012

AbstractNew Hubble images of the reflection nebula CRL 2688 from 0.6 to 1.6μm reveal significant variations of color and opacity in the distribution of scattered starlight. We have constructed a detailed radiation-transfer model consisting principally of an optically thick equatorial disk-like structure; bipolar lobes with density enhancements along the polar axis and at the base of lobes; an optically thin extended envelope containing spherical density-enhanced shells to mimic the outer rings of CRL 2688; and a pair of near-stellar caps that collimate and redden the dispersing starlight near its source. Our model nicely reproduces all of the basic features detected in the HST images, including the famous searchlights and arcs, as well as the measured spectral energy distribution (“SED”) of CRL 2688. Assuming a distance of 420 pc we estimate the light originates in a giant star with a temperature T ~ 7000 K and a luminosity L = 5500 ± 1100 L⊙.
Towards a Legal Framework for Coastal Adaptation: Assessing the First Steps in Europe and Australia
Authors: Verschuuren Jonathan , McDonald Jan 
Published: August 2012

AbstractIn light of the urgent need for coastal adaptation policies and the impediments to their implementation, this article examines the early experience with coastal adaptation policies in the EU (in particular the Netherlands and the UK) and Australia, with a view to identifying the important features of an effective regulatory framework for coastal adaptation. We conclude that an integrated approach to coastal adaptation law is currently needed to lay the foundations for the required long-term strategy. Such an approach would establish processes by which adaptation objectives are agreed for each part of the coast, ensure land use planning that can accommodate future change and does not expose new communities to risk, integrate coastal adaptation with biodiversity and coastal zone policy, allocate regulatory responsibility in a way that promotes subsidiarity and consistency, and ensure that funds are available for future measures.
Structural insight into how Pseudomonas aeruginosa peptidoglycanhydrolase Tse1 and its immunity protein Tsi1 function
Authors: Shang Guijun , Liu Xiuhua , Lu Defen , Zhang Junbing , Li Ning , Zhu Chunyuan , Liu Shiheng , Yu Qian , Zhao Yanyu , Zhang Heqiao , Hu Junqiang , Cang Huaixing , Xu Sujuan , Gu Lichuan 
Published: August 2012

Tse1 (Tse is type VI secretion exported), an effector protein produced by Pseudomonas aeruginosa, is an amidase that hydrolyses the γ-D-glutamyl-DAP (γ-D-glutamyl-L-meso-diaminopimelic acid) linkage of the peptide bridge of peptidoglycan. P. aeruginosa injects Tse1 into the periplasm of recipient cells, degrading their peptidoglycan, thereby helping itself to compete with other bacteria. Meanwhile, to protect itself from injury by Tse1, P. aeruginosa expresses the cognate immunity protein Tsi1 (Tsi is type VI secretion immunity) in its own periplasm to inactivate Tse1. In the present paper, we report the crystal structures of Tse1 and the Tse1-(6–148)–Tsi1-(20-end) complex at 1.4 Å and 1.6 Å (1 Å=0.1 nm) resolutions respectively. The Tse1 structure adopts a classical papain-like α+β fold. A cysteine–histidine catalytic diad is identified in the reaction centre of Tse1 by structural comparison and mutagenesis studies. Tsi1 binds Tse1 tightly. The HI loop (middle finger tip) from Tsi1 inserts into the large pocket of the Y-shaped groove on the surface of Tse1, and CD, EF, JK and LM loops (thumb, index finger, ring finger and little finger tips) interact with Tse1, thus blocking the binding of enzyme to peptidoglycan. The catalytic and inhibition mechanisms provide new insights into how P. aeruginosa competes with others and protects itself.
Identification of a novel malonyl-CoA IC50 for CPT-I: implications for predicting in vivo fatty acid oxidation rates
Authors: Smith Brennan K. , Perry Christopher G. R. , Koves Timothy R. , Wright David C. , Smith Jeffrey C. , Neufer P. Darrell , Muoio Deborah M. , Holloway Graham P. 
Published: August 2012

Published values regarding the sensitivity (IC50) of CPT-I (carnitine palmitoyltransferase I) to M-CoA (malonyl-CoA) inhibition in isolated mitochondria are inconsistent with predicted in vivo rates of fatty acid oxidation. Therefore we have re-examined M-CoA inhibition kinetics under various P-CoA (palmitoyl-CoA) concentrations in both isolated mitochondria and PMFs (permeabilized muscle fibres). PMFs have an 18-fold higher IC50 (0.61 compared with 0.034 μM) in the presence of 25 μM P-CoA and a 13-fold higher IC50 (6.3 compared with 0.49 μM) in the presence of 150 μM P-CoA compared with isolated mitochondria. M-CoA inhibition kinetics determined in PMFs predicts that CPT-I activity is inhibited by 33% in resting muscle compared with &gt;95% in isolated mitochondria. Additionally, the ability of M-CoA to inhibit CPT-I appears to be dependent on P-CoA concentration, as the relative inhibitory capacity of M-CoA is decreased with increasing P-CoA concentrations. Altogether, the use of PMFs appears to provide an M-CoA IC50 that better reflects the predicted in vivo rates of fatty acid oxidation. These findings also demonstrate that the ratio of [P-CoA]/[M-CoA] is critical for regulating CPT-I activity and may partially rectify the in vivo disconnect between M-CoA content and CPT-I flux within the context of exercise and Type 2 diabetes.
Improved thermal and electrical properties of Al-doped Ge2Sb2Te5 films for phase-change random access memory
Authors: Wang Guoxiang , Shen Xiang , Nie Qiuhua , Wang Rongping , Wu Liangcai , Lv Yegang , Chen Fen , Fu Jing , Dai Shixun , Li Jun 
Published: August 2012

Abstract
Al
x
(Ge2Sb2Te5)100−x
materials with different Al contents are systemically studied for applications in phase-change random access memory (PRAM) devices. Al-doped Ge2Sb2Te5 (GST) films show better thermal stability than GST because they do not have phase transformation from face-centred cubic (fcc) to hexagonal at high annealing temperatures. As the Al content increases, the resistance in both amorphous and crystalline phases improves and there is four to five orders of magnitude difference in the resistance between the amorphous and crystalline phases, all of which are helpful in achieving a higher On/OFF ratio for PRAM. In addition, the introduction of Al into the GST films can increase the optical band gap that is favourable to decrease the threshold current of PRAM devices. Raman spectra show that a significant change in the local bonding arrangement around Sb atoms has occurred due to the phase transformation from fcc to hexagonal in the GST film but this can be suppressed by Al addition during the crystallization process. All these results confirm that Al-doped GST films are suitable for use in PRAM.
Annealing improved ductility and fracture toughness of nanocrystalline Cu films on flexible substrates
Authors: Hu K , Cao Z H , Wang L , She Q W , Meng X K 
Published: August 2012

Abstract
In this paper, the effect of annealing temperature (T) on the ductility of 50 nm thick nanocrystalline (NC) Cu films adhered to flexible substrates was investigated by a uniaxial tension test. It was found that the ductility and the fracture toughness (G
c) can be significantly improved through an annealing treatment. The crack onset strain of the 300 °C annealed Cu film is 18.1%, which is about twice that of the as-deposited NC Cu film. In addition, G
c of the 300 °C annealed Cu film is 1833 J m−2, which is nearly three times that of the as-deposited NC Cu film. Focused ion beam results indicate that the as-deposited film fractures with delamination and strain localization coevolving, while the as-annealed film fractures by adhering well to the substrate. At a higher T, the tensile residual stress is lower, the microstructure is more stable, and a diffusion or compound interface is generated, resulting in a better bonding between the film and the substrate. In this case, the strain localization is suppressed more effectively, causing improved ductility and G
c. Whether the film is as-deposited or as-annealed, the saturated crack spacing is about 1.41 µm, which accords well with the theoretical analysis. Intergranular fracture is suggested to be the main fracture mechanism.
Efficacy of apixaban when compared with warfarin in relation to renal function in patients with atrial fibrillation: insights from the ARISTOTLE trial
Authors: Hohnloser Stefan H , Hijazi Ziad , Thomas Laine , Alexander John H , Amerena John , Hanna Michael , Keltai Matyas , Lanas Fernando , Lopes Renato D. , Lopez-Sendon Jose , Granger Christopher B , Wallentin Lars 
Published: August 2012

AbstractAimsAtrial fibrillation (AF) is common among patients with impaired renal function. Apixaban, a novel oral anticoagulant with partial renal excretion, was compared with warfarin and reduced the rate stroke, death and bleeding in the ARISTOTLE trial. We evaluated these outcomes in relation to renal function.Methods and resultsBaseline glomerular filtration rate (GFR) was estimated using the Cockcroft–Gault and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations as well as cystatin C measurements. According to baseline Cockcroft–Gault, there were 7518 patients (42%) with an estimated GFR (eGFR) of >80 mL/min, 7587 (42%) between >50 and 80 mL/min, and 3017 (15%) with an eGFR of ≤50 mL/min. The rate of cardiovascular events and bleeding was higher at impaired renal function (≤80 mL/min). Apixaban was more effective than warfarin in preventing stroke or systemic embolism and reducing mortality irrespective of renal function. These results were consistent, regardless of methods for GFR estimation. Apixaban was associated with less major bleeding events across all ranges of eGFRs. The relative risk reduction in major bleeding was greater in patients with an eGFR of ≤50 mL/min using Cockcroft–Gault {hazard ratio (HR) 0.50 [95% confidence interval (CI) 0.38–0.66], interaction P = 0.005} or CKD-EPI equations [HR 0.48 (95% CI 0.37–0.64), interaction P = 0.003].ConclusionIn patients with AF, renal impairment was associated with increased risk of cardiovascular events and bleeding. When compared with warfarin, apixaban treatment reduced the rate of stroke, death, and major bleeding, regardless of renal function. Patients with impaired renal function seemed to have the greatest reduction in major bleeding with apixaban.
Extractability and Molecular Modifications of Gliadin and Glutenin Proteins Withdrawn from Different Stages of a Commercial Ethanol Fuel/Distillers Dried Grains with Solubles Process Using a Wheat Feedstock
Authors: Hong Geun‐Pyo , Avramenko Nicole , Stone Andrea , Abbott Dawn , Classen Hank , Nickerson Michael 
Published: August 2012

ABSTRACTExtractability and molecular modifications of gliadin and glutenin proteins withdrawn from different stages of a commercial ethanol fuel/distillers dried grains with solubles (DDGS) process using a wheat feedstock were investigated. Materials were taken postliquefaction (PL), postdistillation (whole stillage), and postdrying (DDGS) during the process and then fractionated to separate the gliadins and the soluble high‐ and low‐molecular‐weight glutenins following a modified Verbruggen extraction method. Each fraction was characterized based on the extraction efficiencies within various aqueous alcohols of propan‐1‐ol, electrophoretic patterns, intrinsic and extrinsic fluorescence, free and total sulfhydryl content, and total disulfide bond levels. Findings indicated significant changes to the composition of extracted proteins and modifications to the protein structure (i.e., surface properties and conformation) throughout the ethanol/DDGS process, beginning with the first step of production (PL, ≈83°C). Overall, processing resulted in a shift toward an unextractable gluten matrix, accompanied by increases in hydrophobicity, disulfide bridging, and excessive protein aggregation.