bluuebunny/crossref_metadata_2025_split huggingface dataset:
Saving liberal peacebuilding
Authors: PARIS ROLAND 
Published: April 2010

AbstractLiberal peacebuilding has become the target of considerable criticism. Although much of this criticism is warranted, a number of scholars and commentators have come to the opinion that liberal peacebuilding is either fundamentally destructive, or illegitimate, or both. On close analysis, however, many of these critiques appear to be exaggerated or misdirected. At a time when the future of peacebuilding is uncertain, it is important to distinguish between justified and unjustified criticisms, and to promote a more balanced debate on the meaning, shortcomings and prospects of liberal peacebuilding.
Financial governance and transnational deliberative democracy
Authors: GERMAIN RANDALL 
Published: April 2010

AbstractRecent concern with the institutional underpinning of the international financial architecture has intersected with broader debates concerning the possibility of achieving an adequate deliberative context for decisions involving transnational economic governance. Scholars working within traditions associated with international political economy, deliberative democracy, cosmopolitanism and critical theory have informed this broader debate. This article uses this debate to ask whether the structure of financial governance at the global level exhibits the necessary conditions to support deliberative democracy. In particular, it considers the extent to which publicness and a public sphere have become part of the broader structure of financial governance. Although in some ways financial governance is a hard case for this debate, an argument can be made that a public sphere has emerged as an important element of the international financial architecture. At the same time, the analysis of the role of the public sphere in financial governance reveals important lessons which public sphere theorists and deliberative democracy advocates need to consider in order to extend their analysis into the realm of global political economy.
Timeliness of MMR vaccination and barriers to vaccination in preschool children
Authors: JEONG Y. W. , PARK B. H. , KIM K. H. , HAN Y. R. , GO U. Y. , CHOI W. S. , KONG K. A. , PARK H. 
Published: April 2010

SUMMARYThe documented vaccine coverage rate of measles-mumps-rubella (MMR) vaccination is almost 99% in Korea, but measles cases are constantly being reported. This study evaluated the vaccine coverage, timeliness, and barriers to immunization of measles vaccination in preschool children in Korea. We assessed 452 children aged 15–23 months and 300 children aged 4–6 years in September 2007. Questionnaires were administered in order to estimate measles vaccination rate, its timeliness and barriers to vaccine uptake. Being unaware of the necessity for vaccination and its schedule, child being sick during the recommended vaccination period, and recommended vaccination period not being over were significant preventive factors to timely vaccination (P<0·05). Children with working mothers, single parents, those not being cared for by their parents, and those younger among siblings were at a higher risk of not being vaccinated on time. In order to increase timely vaccination, accurate information should be delivered and a systematic approach should be targeted to high-risk groups.
Putative fossil life in a hydrothermal system of the Dellen impact structure, Sweden
Authors: Lindgren Paula , Ivarsson Magnus , Neubeck Anna , Broman Curt , Henkel Herbert , Holm Nils G. 
Published: April 2010

AbstractImpact-generated hydrothermal systems are commonly proposed as good candidates for hosting primitive life on early Earth and Mars. However, evidence of fossil microbial colonization in impact-generated hydrothermal systems is rarely reported in the literature. Here we present the occurrence of putative fossil microorganisms in a hydrothermal system of the 89 Ma Dellen impact structure, Sweden. We found the putative fossilized microorganisms hosted in a fine-grained matrix of hydrothermal alteration minerals set in interlinked fractures of an impact breccia. The putative fossils appear as semi-straight to twirled filaments, with a thickness of 1–2 μm, and a length between 10 and 100 μm. They have an internal structure with segmentation, and branching of filaments occurs frequently. Their composition varies between an outer and an inner layer of a filament, where the inner layer is more iron rich. Our results indicate that hydrothermal systems in impact craters could potentially be capable of supporting microbial life. This could have played an important role for the evolution of life on early Earth and Mars.
What the D/O ratio tells us about the interstellar abundance of deuterium?
Authors: Hébrard Guillaume 
Published: April 2010

AbstractThe ionization balances for HI, OI and DI being locked together by charge exchange, the deuterium-to-oxygen ratio is considered to be a good proxy for the deuterium-to-hydrogen ratio, in particular within the interstellar medium. As the DI and OI column densities are of similar orders of magnitude for a given sight line, comparisons of the two values are generally less subject to systematic errors than comparisons of DI and HI. Moreover, D/O is additionally sensitive to astration, because as stars destroy deuterium, they should produce oxygen. D/O measurements are now available for tens of lines of sight in the interstellar medium, most of them from FUSE observations. The D/H and D/O ratios show different pictures, D/H being clearly more dispersed than D/O. The low, homogeneous D/O ratio measured on distant lines of sight suggests a deuterium abundance representative of the present epoch that is about two times lower than this measured within the local interstellar medium.
Measurements of4He in metal-poor extragalactic Hiiregions: the primordial Helium abundance and the ΔY/ΔOratio
Authors: Peimbert Manuel , Peimbert A. , Carigi L. , Luridiana V. 
Published: April 2010

AbstractWe present a review on the determination of the primordial helium abundanceYp, based on the study of hydrogen and helium recombination lines in extragalactic Hiiregions. We also discuss the observational determinations of the increase of helium to the increase of oxygen by mass ΔY/ΔO, and compare them with predictions based on models of galactic chemical evolution.
The quite complex “Simple Stellar Populations” of globular clusters
Authors: Bragaglia Angela 
Published: April 2010

AbstractThere is compelling observational evidence that globular clusters (GCs) are quite complex objects. A growing body of photometric results indicate that the evolutionary sequences are not simply isochrones in the observational plane -as believed until a few years ago- from the main sequence, to the subgiant, giant, and horizontal branches. The strongest indication of complexity comes however from the chemistry, from internal dispersion in iron abundance in a few cases, and in light elements (C, N, O, Na, Mg, Al, etc.) in all GCs. This universality means that the complexity is intrinsic to the GCs and is most probably related to their formation mechanisms. The extent of the variations in light elements abundances is dependent on the GC mass, but mass is not the only modulating factor; metallicity, age, and possibly orbit can play a role. Finally, one of the many consequences of this new way of looking at GCs is that their stars may show different He contents.
The Helium contribution from massive AGBs
Authors: Ventura Paolo 
Published: April 2010

AbstractThe helium produced by AGB and super-AGB stars is a key quantity to understand whether these objects may have been the main polluters of the interstellar medium within globular clusters, and originate a second generation of stars with a chemistry showing the imprinting of their ejecta. Helium is the most important element for this topic, as any difference in the original helium between the two populations would determine clearly distinguishable features both in the morphology of the Horizontal Branches and in the Main Sequences. We present the helium yields from massive AGB stars, and show that the results are rather robust, being approximately independent of the various uncertainties that affect the description of the evolution of these stars. The implications for the self-enrichment scenario are discussed and commented.
Discussion A: On the abundance of deuterium in the local interstellar medium and in high-redshift systems
Authors: Tosi Monica 
Published: April 2010

AbstractThe first discussion session held at the IAU Symposium 268 focussed on the deuterium content in the local interstellar medium (LISM) and in high-redshift systems. There were two key questions proposed to the audience: 1) what should be taken as representative abundance of D in the LISM, and 2) how can we explain the dispersion of the D abundance measured in high-redshift, very low metallicity environments? While on the latter point people seem to agree that observational and data analyses uncertainties are the most likely explanation, on the former question no consensus was reached. The historical and observational background at the basis of these questions and the discussion are schematically reported here.
What is 4He from H II regions? What needs to be done to better understand the systematic errors?
Authors: Ferland Gary J. , Izotov Yuri , Peimbert Antonio , Peimbert Manuel , Porter Ryan L. , Skillman Evan , Steigman Gary 
Published: April 2010

AbstractHere we summarize the discussion that took place after the presentation of papers discussing measurement of abundances from emission lines in H II regions. A cosmological test using 4He is harder than those using the other light elements due to the small dynamic range over which He/H varies for cosmologically interesting parameters. A precision of much better than 1% is needed. This precision challenges both observations and theory. Several of the major uncertainties were identified and methods of improving the accuracy were described.
On the total O/H abundance ratio in Galactic and extragalactic H ii regions
Authors: Peimbert Antonio , Peimbert Manuel 
Published: April 2010

AbstractTo determine the primordial helium abundance and to study the chemical evolution of galaxies it is necessary to derive the total O/H ratio in H ii regions. To determine the total O/H ratio in H ii regions it is necessary to add to the gas-phase component the dust-phase component of O atoms. Based on the Fe/O ratio and other considerations we estimate the dust-phase fraction as a function of O/H.
Beryllium and boron in metal-poor stars
Authors: Primas Francesca 
Published: April 2010

AbstractKnowledge of lithium, beryllium, and boron abundances in stars of the Galactic halo and disk plays a major role in our understanding of Big Bang nucleosynthesis, cosmic-ray physics, and stellar interiors. 9Be and 10B are believed to originate entirely from spallation reactions in the interstellar medium (ISM) between α-particles and protons and heavy nuclei like carbon, nitrogen, and oxygen (CNO), whereas 11B may have an extra production channel via neutrino-spallation. Beryllium and boron are both observationally challenging, with their main resonant doublets falling respectively at 313 nm and at 250 nm. The advent of 8-10m class telescopes equipped with highly sensitive (in the near-UV/blue) spectrographs has opened up a new era of Be abundance studies. Here, I will review and discuss the most interesting results of recent observational campaigns in terms of formation and evolution of these two light elements.
New Beryllium results in halo stars from Keck/HIRES spectra
Authors: Boesgaard Ann Merchant , Rich Jeffrey A. , Levesque Emily M. , Bowler Brendan P. 
Published: April 2010

AbstractWe have obtained high-resolution, high signal-to-noise Keck spectra to determine Be abundances in over 100 stars in the Galactic halo. The stellar metallicities range from [Fe/H] = −0.50 to −3.50. Using this large sample, we have examined the trends of Be with Fe and Be with O. We find a real dispersion in Be at a given [O/H] that indicates that Be may not be a good cosmochronometer. Our results indicate that the dominant production mechanism for Be changes as the Galaxy ages. In the early eras of the Galaxy, when massive stars become supernovae, Be is produced from the acceleration of energetic CNO atoms which bombard protons in the vicinity of supernovae. Later spallation reactions occur as high energy protons bombard CNO atoms in the interstellar gas. The change occurs near [Fe/H] = −2.2. We have found that Be is deficient in Li-deficient halo stars, which favors the blue straggler analog hypothesis.
Boron abundances in the Galactic disk
Authors: Cunha Katia 
Published: April 2010

AbstractWhen compared to lithium and beryllium, the absence of boron lines in the optical results in a relatively small data set of boron abundances measured in Galactic stars to date. In this paper we discuss boron abundances published in the literature and focus on the evolution of boron in the Galaxy as measured from pristine boron abundances in cool stars as well as early-type stars in the Galactic disk. The trend of B with Fe obtained from cool F-G dwarfs in the disk is found to have a slope of 0.87 ± 0.08 (in a log-log plot). This slope is similar to the slope of B with Fe found for the metal poor halo stars and there seems to be a smooth connection between the halo and disk in the chemical evolution of boron. The disk trend of boron with oxygen has a steeper slope of 1.5. This slope suggests an intermediate behavior between primary and secondary production of boron with respect to oxygen. The slope derived for oxygen is consistent with the slope obtained for Fe provided that [O/Fe] increases as [Fe/H] decreases, as observed in the disk.
Main-sequence and sub-giant stars in the globular cluster NGC 6397: The complex evolution of the lithium abundance
Authors: González Hernández J. I. , Bonifacio P. , Caffau E. , Steffen M. , Ludwig H.-G. , Behara N. , Sbordone L. , Cayrel R. , Zaggia S. 
Published: April 2010

AbstractThanks to the high multiplex and efficiency of Giraffe at the VLT we have been able for the first time to observe the Li I doublet in the Main Sequence stars of a globular cluster. At the same time we observed Li in a sample of Sub-Giant stars of the same B-V colour.Our final sample is composed of 84 SG stars and 79 MS stars. In spite of the fact that SG and MS span the same temperature range we find that the equivalent widths of the Li I doublet in SG stars are systematically larger than those in MS stars, suggesting a higher Li content among SG stars. This is confirmed by our quantitative analysis carried out making use of 1D hydrostatic plane-parallel models and 3D hydrodynamical simulations of the stellar atmospheres.We derived the effective temperatures of stars in our the sample from Hα fitting. Theoretical profiles were computed using 3D hydrodynamical simulations and 1D ATLAS models. Therefore, we are able to determined 1D and 3D-based effective temperatures. We then infer Li abundances taking into account non-local thermodynamical equilibrium effects when using both 1D and 3D models.We find that SG stars have a mean Li abundance higher by 0.1 dex than MS stars. This result is obtained using both 1D and 3D models. We also detect a positive slope of Li abundance with effective temperature, the higher the temperature the higher the Li abundance, both for SG and MS stars, although the slope is slightly steeper for MS stars. These results provide an unambiguous evidence that the Li abundance changes with evolutionary status.The physical mechanisms responsible for this behaviour are not yet clear, and none of the existing models seems to describe accurately these observations. Based on these conclusions, we believe that the cosmological lithium problem still remains an open question.
Lithium abundances in Bulge-like SMR stars
Authors: Barbuy Beatriz , Trevisan M. , Gustafsson B. , Eriksson K. , Grenon M. , Pompéia L. 
Published: April 2010

AbstractWe analyze a sample of 21 super-metal-rich (SMR) stars, using high-resolution échelle spectra obtained with the FEROS Spectrograph at the 1.5m ESO telescope. The metallicities are in the range 0.15 < [Fe/H] < 0.5, 3 of them in common with Pompéia et al. (2002). Geneva photometry, astrometric data from Hipparcos, and radial velocities from CORAVEL are available for these stars. The peculiar kinematics suggests the thin disk close to the bulge as the probable birthplace of these stars (Grenon 1999). From Hipparcos data, it appears that the turnoff of this population indicates an age of 10-11 Gyr (Grenon 1999). Detailed analysis of the sample stars is carried out. Lithium abundances of these stars were derived, and their behaviour with effective temperature is shown.
Beryllium abundances in metal-rich stars
Authors: Peterson Ruth C. 
Published: April 2010

AbstractIn metal-rich stars as cool as the Sun, beryllium abundance determinations are difficult due to heavy line blanketing in the near-UV 3130 Å region where the accessible Be II lines reside. We can now attempt such determinations based on improved lists of atomic line identifications and gf-values in the near-UV. Here we report Be determinations for three metal-rich A, F, and G stars plus three solar-metallicity standards. All six stars have beryllium-to-hydrogen ratios at or below solar. More such determinations would provide stronger constraints on trends in Be abundance with temperature, metallicity, and age.
Beryllium abundances along the evolutionary sequence of the open cluster IC 4651
Authors: Smiljanic Rodolfo , Pasquini L. , Charbonnel C. , Lagarde N. 
Published: April 2010

AbstractThe simultaneous investigation of Li and Be in stars is a powerful tool in the study of the evolutionary mixing processes. Here, we present beryllium abundances in stars along the whole evolutionary sequence of the open cluster IC 4651. This cluster has a metallicity of [Fe/H] = +0.11 and an age of 1.2 or 1.7 Gyr. Abundances have been determined from high-resolution, high signal-to-noise UVES spectra using spectrum synthesis and model atmospheres. Lithium abundances for the same stars were determined in a previous work. Confirming previous results, we find that the Li dip is also a Be dip. For post-main-sequence stars, the Be dilution starts earlier within the Hertzsprung gap than expected from classical predictions, as does the Li dilution. Theoretical hydrodynamical models are able to reproduce well all the observed features.
Lithium in metal-poor red giants
Authors: Začs Laimons , Barzdis Arturs 
Published: April 2010

AbstractThe lithium abundance was calculated for five metal-poor red giant stars from Li i doublet at 6707 Å by fitting the observed high-resolution spectra with synthetic spectra. The lithium abundance was found to be low in all stars, logϵ(Li) ≤ 1.8, confirming lithium depletion on the red giant and asymptotic giant branch.
Rotational mixing and Lithium depletion
Authors: Pinsonneault M. H. 
Published: April 2010

AbstractI review basic observational features in Population I stars which strongly implicate rotation as a mixing agent; these include dispersion at fixed temperature in coeval populations and main sequence lithium depletion for a range of masses at a rate which decays with time. New developments related to the possible suppression of mixing at late ages, close binary mergers and their lithium signature, and an alternate origin for dispersion in young cool stars tied to radius anomalies observed in active young stars are discussed. I highlight uncertainties in models of Population II lithium depletion and dispersion related to the treatment of angular momentum loss. Finally, the origins of rotation are tied to conditions in the pre-main sequence, and there is thus some evidence that environment and planet formation could impact stellar rotational properties. This may be related to recent observational evidence for cluster to cluster variations in lithium depletion and a connection between the presence of planets and stellar lithium depletion.
Lithium factories in the Galaxy: novae and AGB stars
Authors: D'Antona Francesca , Ventura Paolo 
Published: April 2010

AbstractWe review the state of the art in modelling lithium production, through the Cameron–Fowler mechanism, in two stellar sites: during nova explosions and in the envelopes of massive asymptotic giant branch (AGB) stars. We also show preliminary results concerning the computation of lithium yields from super–AGBs, and suggest that super–AGBs of metallicity close to solar may be the most important galactic lithium producers. Finally, we discuss how lithium abundances may help to understand the modalities of formation of the “second generation” stars in globular clusters.
Li and CNO isotopes from magnetically induced extra-mixing in evolved stars
Authors: Palmerini Sara , Busso Maurizio , Guandalini Roald , Maiorca Enrico 
Published: April 2010

AbstractEvolved low mass stars (LMS) contribute not only to the synthesis of s-process nuclei, but also to modifications in the isotopic mix of light elements (Li and CNO especially), induced by proton captures. In particular, RGB and AGB stars show a wide range of Li abundances. This spread is currently attributed to deep phenomena of non-convective mixing. These processes can, in principle, either produce or destroy Li, depending on their velocity. This is due to the fact that Li production requires preserving the unstable 7Be, which has a half-life of only 53 days. Physical mechanisms devised so far to explain the existence of deep mixing in low mass stars generally fail in accounting for fast transport and in avoiding 7Be destruction; on the contrary, this is easily obtained in Intermediate Mass Stars, where Hot Bottom Burning can occur. However, as Li-rich low-mass red giants do exist, we propose here a scenario where both production and destruction of Li are possible in LMS, thanks to the buoyancy of magnetized parcels of processed matter, traveling from the H shell to the envelope at different speeds (depending on their size). Consequences of this transport for CNO nuclei are also discussed.
Galactic evolution of D, 3He and 4He
Authors: Romano Donatella 
Published: April 2010

AbstractThe uncertainties which still plague our understanding of the evolution of the light nuclides D, 3He and 4He in the Galaxy are described. Measurements of the local abundance of deuterium range over a factor of 3. The observed dispersion can be reconciled with the predictions on deuterium evolution from standard Galactic chemical evolution models, if the true local abundance of deuterium proves to be high, but not too high, and lower observed values are due to depletion onto dust grains. The nearly constancy of the 3He abundance with both time and position within the Galaxy implies a negligible production of this element in stars, at variance with predictions from standard stellar models which, however, do agree with the (few) measurements of 3He in planetary nebulae. Thermohaline mixing, inhibited by magnetic fields in a small fraction of low-mass stars, could in principle explain the complexity of the overall scenario. However, complete grids of stellar yields taking this mechanism into account are not available for use in chemical evolution models yet. Much effort has been devoted to unravel the origin of the extreme helium-rich stars which seem to inhabit the most massive Galactic globular clusters. Yet, the issue of 4He evolution is far from being fully settled even in the disc of the Milky Way.