bluuebunny/crossref_metadata_2025 huggingface dataset:
In Search of Judicial Activism in the Same-Sex Marriage Cases: Sorting the Evidence from Courts, Legislatures, Initiatives and Amendments
Authors: Barclay Scott
Published: March 2010

In 2006, President Bush publicly stated that, in relation to the same-sex marriage issue, “activist judges” were thwarting the preferred policy of the elected representatives and the expression of popular will embodied in popular initiatives and constitutional amendments. Notwithstanding the philosophical discussion of the constitutionally assigned role of courts in the political system and the idea of judicial independence, President Bush's statement raises an interesting empirical question: In the case of same-sex marriage, have state and federal courts really acted in direct opposition to the expressed policy preferences of current or recent legislative majorities or overturned popular initiatives and constitutional amendments? Using evidence from state and federal legislative and judicial action around same-sex marriage primarily from the fifteen years preceding President Bush's 2006 statement, I argue that, with some rare exceptions, judges can not easily be identified as “activist” on the issue of same-sex marriage even if we assess their actions according to President Bush's criteria.
Gendering Comparative Politics
Authors: Caraway Teri L.
Published: March 2010

This essay offers a conceptualization of a comparative politics of gender (CPG) and some explanations for why CPG work is marginalized in the comparative politics subfield. I delineate CPG as a field of study in which gendered dependent or independent variables are the defining feature and present illustrative examples of four different types of CPG research. I contend that institutional and historical factors account for much of the marginalization of CPG research, and I propose some courses of actions through which CPG scholars can lessen this marginalization. The failure of comparative politics scholars to engage with gendered work is also a serious problem. The essay concludes by offering some suggestions for better integrating CPG scholarship into the subfield.
Comparison and Integration: A Path toward a Comparative Politics of Gender
Authors: Schwindt-Bayer Leslie A.
Published: March 2010

Moving from a “gender and comparative politics” to a “comparative politics of gender” is a challenging proposition. In this essay, I offer two mechanisms for doing this—emphasizing the comparative nature of gender politics research and encouraging greater integration of gender research into the subfield of comparative politics. I illustrate how current research generally uses a “gender and comparative politics” approach that is insufficient for advancing the field and then describe how scholars can work to emphasize greater comparison and integration in the literature. This will help to move the gender and politics literature toward a comparative politics of gender.
Comparing Gender, Institutions and Political Behavior: Toward an Integrated Theoretical Framework
Authors: Kittilson Miki Caul
Published: March 2010

Integrating the behavioral and institutional approaches to comparative politics will provide a more comprehensive theoretical framework for understanding why differences in political engagement among men and women vary cross-nationally and cross-temporally. This essay advances the argument that gender-related policies and institutions are not only outcomes in the political process, but also exert powerful influence over citizens' interests, values, and perceptions of politics. This policy feedback loop has implications for a wide array of political attitudes and activities—from political interest to running for elected office. Specifically, the adoption and expansion of national policies on issues such as equal wages, childcare provision, paid maternity leave, and violence against women carry important messages to the electorate: Issues that disproportionately affect women, long considered private, have become important national policy choices.
A Comparative Politics of Gender: Limits and Possibilities
Authors: Waylen Georgina
Published: March 2010

I explore some of the limits and possibilities for a comparative politics of gender (CPG). It argues that a CPG should analyze how major political processes and institutions are gendered thereby increasing our understanding of the major themes of comparative politics and enhancing the subfield. But a CPG should also go beyond this. It should be problem driven and should seek to answer some “big questions” that are important for any efforts to achieve gender equality such as how political change that lessens gender inequality occurs; and how positive gender outcomes come about in a range of contexts. A CPG therefore has an integral connection to a feminist project. I explore some of these themes using the recent literature on gender and transitions to democracy to answer the question under what circumstances can the gender outcomes of transitions be positive.
Introduction: Selling Out? Solidarity and Choice in the American Feminist Movement
Authors: Kirkpatrick Jennet
Published: March 2010

This symposium examines an emergent orientation within the American feminist movement called “choice feminism.” Choice feminists are primarily concerned with increasing the number of choices open to women and with decreasing judgments about the choices that individual women make. Choice feminists are best known for their argument that a woman who leaves the remunerated labor market to care for her children is a feminist in good standing; she makes a feminist decision. While media coverage of choice feminism has been extensive, political scientists have been comparatively quiet. In this symposium, four political scientists analyze and evaluate choice feminism, revealing their disagreement about the validity of the choice feminist position and about the meaning of choice feminism for movement politics, political judgment, and liberal political theory.
Insights into the s-process and r-process as revealed by globular clusters
Authors: Yong D. , Karakas A. I. , Lambert D. L. , Chieffi A. , Limongi M.
Published: March 2010

We present abundance measurements for a large number of neutron-capture elements in giant stars of the globular clusters M4, M5, and M13. The relative abundance ratios differ between all three clusters. For all clusters, we find that the mean abundances for the elements from Ba to Hf can be well explained by scaled versions of the solar s- and r-process abundances, albeit with different mixtures of s- and r-process material for each clusters.
Mass and angular momentum loss of first stars via decretion disks
Authors: Krtička Jiří , Owocki Stanley P. , Meynet Georges
Published: March 2010

Although the first stars were likely very hot and luminous, their low or zero metallicity implies that any mass loss through winds driven by line-scattering of radiation in metal ions was likely small or non-existent. Here we examine the potential role of another possible mechanism for mass loss in these first stars, namely via decretion disks associated with near-critical rotation induced from evolution of the stellar interior. In this case the mass loss is set by the angular momentum needed to keep the stellar rotation at or below the critical rate. In present evolutionary models, that mass loss is estimated by assuming effective release from a spherical shell at the surface. Here we examine the potentially important role of viscous coupling of the decretion disk in outward angular momentum transport, emphasizing that the specific angular momentum at the outer edge of the disk can be much larger than at the stellar surface. The net result is that, for a given stellar interior angular momentum excess, the mass loss required from a decretion disk can be significantly less than invoked in previous models assuming a direct, near-surface release.
The metal–poor end of the Spite plateau
Authors: Sbordone L. , Bonifacio P. , Caffau E. , Ludwig H.-G. , Behara N. , Gonzalez-Hernandez J. I. , Steffen M. , Cayrel R. , Freytag B. , Van't Veer C. , Molaro P. , Plez B. , Sivarani T. , Spite M. , Spite F. , Beers T. C. , Christlieb N. , François P. , Hill V.
Published: March 2010

We present the largest sample available to date of lithium abundances in extremely metal poor (EMP) Halo dwarfs. Four Teff estimators are used, including IRFM and Hα wings fitting against 3D hydrodynamical synthetic profiles. Lithium abundances are computed by means of 1D and 3D-hydrodynamical NLTE computations. Below [Fe/H]~−3, a strong positive correlation of A(Li) with [Fe/H] appears, not influenced by the choice of the Teff estimator. A linear fit finds a slope of about 0.30 dex in A(Li) per dex in [Fe/H], significant to 2–3 σ, and consistent within 1 σ among all the Teff estimators. The scatter in A(Li) increases significantly below [Fe/H]~−3. Above, the plateau lies at 〈A(Li)3D, NLTE〉 = 2.199 ± 0.086. If the primordial A(Li) is the one derived from standard Big Bang Nucleosynthesis (BBN), it appears difficult to envision a single depletion phenomenon producing a thin, metallicity independent plateau above [Fe/H] = −2.8, and a highly scattered, metallicity dependent distribution below.
A search for s-process elements in extremely metal-poor halo planetary nebulae
Authors: Otsuka Masaaki , Tajitsu Akito , Izumiura Hideyuki , Hyung Siek
Published: March 2010

We have performed deep high-dispersion spectroscopy to examine enhancement of s-process elements in the exremely metal-poor ([Ar/H]~−2.1) halo planetary nebulae H4-1 and BoBn1 using the 8.2-m Subaru telescope/High-Dispersion Spectrograph (HDS). We have detected several emission lines of s-process elements in H4-1 and BoBn1, and we have found that the enhancement of heavy s-process elements in these objects is comparable with that in s-process enhanced CEMP stars with [Fe/H]>−2.5. The C- and N-rich abundances of H4-1 and BoBn1 might be explained by binary evolution models. We have detected 5 fluorine lines in BoBn1. The re-estimated F abundance using these lines is [F/H]=+1.4±0.1.
The most oxygen-poor planetary nebula: AGB nucleosynthesis at low metallicities
Authors: Stasińska G. , Morisset C. , Tovmassian G. , Rauch T. , Decressin T.
Published: March 2010

TS01 is an exceptional planetary nebula (PN) in the Galactic halo: it is the most oxygen-poor and has a double-degenerate core with mass close to 1.4M⊙, possibly a Supernova Ia progenitor. With data from the far UV to the IR we can pin down the abundances of half a dozen of elements. The oxygen abundance is by 1.9(±0.3) dex lower than in the Sun. Standard AGB models with appropriate mass and metallicity cannot explain the observed chemical composition. We find that additional mixing, induced by stellar rotation and/or by the presence of the close companion can explain most of the features of the abundance pattern in TS01.
Nucleosynthesis in Rotating massive stars and Abundances in the Early Galaxy
Authors: Meynet Georges , Hirschi Raphael , Ekstrom Sylvia , Maeder André , Georgy Cyril , Eggenberger Patrick , Chiappini Cristina
Published: March 2010

We discuss three effects of axial rotation at low metallicity. The first one is the mixing of the chemical species which is predicted to be more efficient in low metallicity environments. A consequence is the production of important quantities of primary14N,13C,22Ne and a strong impact on the nucleosynthesis of thes-process elements. The second effect is a consequence of the first. Strong mixing makes possible the apparition at the surface of important quantities of CNO elements. This increases the opacity of the outer layers and may trigger important mass loss by line driven winds. The third effect is the fact that, during the main-sequence phase, stars, at very low metallicity, reach more easily than their more metal rich counterparts, the critical velocity. We discuss the respective importance of these three effects as a function of the metallicity. We show the consequences for the early chemical evolution of the galactic halo and for explaining the CEMP stars. We conclude that rotation is probably a key feature which contributes in an important way to shape the evolution of the first stellar generations in the Universe.
Turbulent Mixing in Stars: Theoretical Hurdles
Authors: Arnett W. David , Meakin Casey
Published: March 2010

A program is outlined, and first results described, in which fully three-dimensional, time dependent simulations of hydrodynamic turbulence are used as a basis for theoretical investigation of the physics of turbulence. The inadequacy of the treatment of turbulent convection as a diffusive process is indicated. A generalization to rotation and magnetohydrodynamics is indicated, as are connections to simulations of 3D stellar atmospheres.
High-resolution spectroscopic observations of two chemically peculiar metal-poor stars: HD 10613 & BD+04°2466
Authors: Pereira C. B. , Drake N. A.
Published: March 2010

We determined the atmospheric parameters and abundance pattern of two chemically peculiar metal-poor stars: HD 10613 and BD+04°2466 and discuss the nature of these two objects.
Chemical Abundances in Star-Forming Galaxies at High Redshift
Authors: Erb Dawn K.
Published: March 2010

A galaxy's metallicity provides a record of star formation, gas accretion, and gas outflow, and is therefore one of the most informative measurements that can be made at high redshift. It is also one of the most difficult. I review methods of determining chemical abundances in distant star-forming galaxies, and summarize results for galaxies at 1 ≲ z ≲ 3. I then focus on the mass-metallicity relation, its evolution with redshift, and its uses in constraining inflows and outflows of gas, and conclude with a brief discussion of future prospects for metallicity measurements at high redshift.
The chemical history of the nearest starburst galaxy – IC10
Authors: Gonçalves Denise R. , Magrini Laura
Published: March 2010

The irregular dwarf galaxy IC10 is located within the Local Group (LG) at a distance of 750 kpc. Although several studies have revealed the existence of stellar populations with a broad range of ages, its star formation history (SFH) and age-metallicity (AM) relationship remain quite unknown. In this contribution we present our spectroscopic investigation of 15 H ii regions, 9 planetary nebulae (PNe) and 1 symbiotic star –so far the farthest known symbiotic binary. Our main goal is to reconstruct the SFH of IC10 and to constrain its AM relationship using young and intermediate-age stars. The direct availability of the electron temperature in our emission-line spectra allows an accurate determination of the IC10 metallicity map at two different epochs. We find a non-homogeneous distribution of metals at both epochs, but similar average abundances for the two analyzed populations. The derived AM relationship shows a little global enrichment, which is interpreted as due to the loss of metals by supernovae winds and to differential gas outflows. Our results bring strong observational constraints to the chemical enrichment history of IC10, the formation of dwarf irregular galaxies and the evolution of the LG as well.
Constraining the Intergalactic Medium Enrichment History with QSO Pairs
Authors: Scannapieco Evan , Martin Crystal L.
Published: March 2010

Intergalactic metals are ubiquitous, but their sources remain unknown. A key constraint on these sources is the spatial distributions of metals. Yet, the clustering of metals is difficult to interpret along single lines-of-sight, because distance and velocity information are mixed in redshift space. To overcome this situation we are carrying out detailed comparisons between the line-of-sight and transverse distributions of metal line absorption systems observed in a large sample of QSO pairs and simulations including a wide range of IGM-enrichment scenarios. The degeneracy between distance and velocity is broken by the transverse information available in pairs of sightlines, and thus these comparisons are providing unique new constraints on when and where metals were ejected from galaxies.
Metallicity of the high-redshift Universe traced by radio galaxies
Authors: Matsuoka K. , Nagao T. , Maiolino R. , Marconi A. , Taniguchi Y.
Published: March 2010

We investigate the metallicity of the narrow line regions (NLRs) of high-z radio galaxies (HzRGs), using new deep optical spectra of 9 HzRGs obtained with FORS2 on VLT and data from the literature. To estimate the metallicity of NLRs we focus on the Civ/Heii and Ciii]/Civ flux ratios. Based on comparison between the observed emission-line flux ratios and the prediction of our photoionization model calculations, we find no significant metallicity evolution in NLRs of HzRGs, up to z ~ 4. We discuss the possibility that massive galaxies had almost completed the major epoch of the star formation in the very high-z universe (z > 5).
Are “realistic” model atmospheres realistic enough?
Authors: Gustafsson Bengt
Published: March 2010

During the latest decades the number of papers on stellar chemical abundances has increased dramatically. This is basically reflecting the very great achievements in telescope- and spectrometer-construction technology. The analysis of the resulting stellar spectra, however, is still not up to the standard that is offered by the observational methods. Recent significant advances in the analysis methods (i.e., in constructing model atmospheres and model spectra to compare with the observed ones) is reviewed with the emphasis on the application to abundance analysis of late-type stars. It is found that the very considerable progress that have been made beyond mixing-length convection and LTE is a major break-through for physically consistent modeling. Still, however, further steps must be taken, in particular for the cooler stars, before the situation is fully satisifactory.
Solar abundances and 3D model atmospheres
Authors: Ludwig Hans-Günter , Caffau Elisabetta , Steffen Matthias , Bonifacio Piercarlo , Freytag Bernd , Cayrel Roger
Published: March 2010

We present solar photospheric abundances for 12 elements from optical and near-infrared spectroscopy. The abundance analysis was conducted employing 3D hydrodynamical (CO5BOLD) as well as standard 1D hydrostatic model atmospheres. We compare our results to others with emphasis on discrepancies and still lingering problems, in particular exemplified by the pivotal abundance of oxygen. We argue that the thermal structure of the lower solar photosphere is very well represented by our 3D model. We obtain an excellent match of the observed center-to-limb variation of the line-blanketed continuum intensity, also at wavelengths shortward of the Balmer jump.
Stellar vs. Hii region chemical abundances in nearby galaxies
Authors: Bresolin Fabio
Published: March 2010

We have obtained new spectrophotometric data for 28 Hii regions in the spiral galaxy NGC 300, a member of the nearby Sculptor Group. The detection of several auroral lines has allowed us to measure electron temperatures and direct chemical abundances for the whole sample. We determine for the first time in this galaxy a radial gas-phase oxygen abundance gradient based solely on auroral lines. The gradient corresponds to −0.077±0.006 dex kpc−1, which agrees very well with the galactocentric trend in metallicity obtained for 29 B and A supergiants in the same galaxy. The intercept of the regression for the nebular data virtually coincides with the intercept obtained from the stellar data. This result provides increased confidence on the direct method to determine extragalactic nebular abundances.
Haro15: Is it actually a low metallicity galaxy?
Authors: Firpo Verónica , Bosch Guillermo , Hägele Guillermo , Díaz Ángeles I. , Morrell Nidia
Published: March 2010

We present a detailed study of the physical properties of the nebular material in multiple knots of the blue compact dwarf galaxy Haro 15. Using long slit and echelle spectroscopy, obtained at Las Campanas Observatory, we study the physical conditions (electron density and temperature), ionic and total chemical abundances of several atoms, reddening and ionization structure. The latter was derived by comparing the oxygen and sulphur ionic ratios to their corresponding observed emission line ratios (the η and η' plots) in different regions of the galaxy. Applying direct and empirical methods for abundance determination, we perform a comparative analysis between these regions.
Chemo-dynamical substructure of the Galactic halo
Authors: Rocha-Pinto Helio J.
Published: March 2010

Deep recent surveys have considerably improved our picture of the outer Galactic halo by unveiling a complex level of substructuring in the form of streams, stellar clouds and debris systems. Here I discuss some of the recent findings and present their general properties.
Evidence of Omega Cen tidal debris in the Kapteyn moving group
Authors: Boer Elizabeth Wylie-de , Freeman Kenneth , Williams Mary
Published: March 2010

This paper presents a detailed kinematic and chemical analysis of 16 members of the Kapteyn moving group. The group does not appear to be chemically homogenous. However, the kinematics and the chemical abundance patterns seen in 14 of the stars in this group are similar to those observed in the well-studied cluster, ω Centauri. Some members of this moving group may be remnants of the tidal debris of ω Cen, left in the Galactic disk during the merger event which deposited ω Cen into the Milky Way. A more detailed version of this work can be found in Wylie de-Boer et al. 2009.
Modelling the Chemical Evolution
Authors: Hensler Gerhard , Recchi Simone
Published: March 2010

Advanced observational facilities allow to trace back the chemical evolution of the Universe, on the one hand, from local objects of different ages and, secondly, by direct observations of redshifted objects. The chemical enrichment serves as one of the cornerstones of cosmological evolution. In order to understand this chemical evolution in morphologically different astrophysical objects models are constructed based on analytical descriptions or numerical methods. For the comparison of their chemical issues, as there are element abundances, gradients, and ratios, with observations not only the present-day values are used but also their temporal evolution from the first era of metal enrichment. Here we will provide some insight into basics of chemical evolution models, highlight advancements, and discuss a few applications.
Fe-peak element abundances in disk and halo stars
Authors: Bergemann Maria , Gehren Thomas
Published: March 2010

At present none of galactic chemical evolution (GCE) models provides a self-consistent description of observed trends for all iron-peak elements with metallicity simultaneously. The question is whether the discrepancy is due to deficiencies of GCE models, such as stellar yields, or due to erroneous spectroscopically-determined abundances of these elements in metal-poor stars. The present work aims at a critical reevaluation of the abundance trends for several odd and even-Z Fe-peak elements, which are important for understanding explosive nucleosynthesis in supernovae.
Photometric and spectroscopic analysis of the stellar association AB Doradus
Authors: Katime-Santrich Orlando J. , Castilho Bruno V. , Torres Carlos A. O. , Quast Germano R.
Published: March 2010

We present the stellar parameters and lithium abundance for 23 stars of the young stellar association AB Doradus, determined by photometry and spectroscopy. The photometric data was obtained at OPD/LNA and/or from the literature and the spectroscopic data was obtained at La silla/ESO and at OPD/LNA. The parameters were determined using photometric calibrations, line ratios, curves of growth and spectral synthesis. Our results confirm that the selected stars are probably association members, showing an uniform metallicity and lithium depletion consistent with 50 Myears
Nucleosynthesis in the Hyades Open Cluster: Evidence for the Enhanced Depletion of 12C
Authors: Schuler Simon C. , King Jeremy R. , The Lih-Sin
Published: March 2010

We present the results of a light element abundance analysis of three solar-type main sequence (MS) dwarfs and three red giant branch (RGB) clump stars in the Hyades open cluster using high-resolution and high signal-to-noise spectroscopy. The CNO abundances of each group (MS or RGB) are in excellent star-to-star agreement and confirm that the giants have undergone first dredge-up mixing. The observed abundances are compared to predictions of a standard stellar model based on the Clemson-American University of Beirut (CAUB) stellar evolution code. The model reproduces the observed evolution of the N and O abundances, as well as the previously derived 12C/13C ratio, but it fails to predict the observed level of 12C depletion in the giants. More tellingly, the sum of the observed giant CNO abundances does not equal that of the dwarfs.
Metal-rich infall onto the inner disk through the interaction between bulge winds and gaseous halos
Authors: Tsujimoto Takuji , Bekki Kenji
Published: March 2010

We demonstrate for the first time that gaseous halos of disk galaxies can play a vital role in recycling metal-rich gas ejected from the bulges and thus in promoting the chemical evolution of the disks. Our numerical simulations show that metal-rich bulge winds can be accreted onto the thin disks owing to hydrodynamical interaction between the gaseous ejecta and the gaseous halos. Accordingly, we anticipate that chemical abundances of the inner disk stars are significantly influenced by the enriched winds. About ~1% of gaseous ejecta from the bulges can be accreted onto the middle disk corresponding to the sun's position. We discuss these results in the context of the origin of super metal-rich stars in the solar neighborhood as well as an observed flattening of the abundance gradient in the Galactic disk.
On the Frequency of Gas Giant Planets in the Metal-Poor Regime
Authors: Sozzetti A. , Latham D. W. , Torres G. , Carney B. W. , Laird J. B. , Stefanik R. P. , Boss A. P. , Korzennik S.
Published: March 2010

We present an analysis of three years of precision radial velocity measurements of 160 metal-poor stars observed with Keck/HIRES. We report on variability and long-term velocity trends for each star in our sample. We identify several long-term, low-amplitude radial-velocity variables worthy of follow-up with direct imaging techniques. We place lower limits on the detectable companion mass as a function of orbital period. None of the stars in our sample exhibits radial-velocity variations compatible with the presence of Jovian planets with periods shorter than the survey duration (3 yr). The resulting average frequency of gas giants orbiting metal-poor dwarfs with −2.0≤[Fe/H]≤ −0.6 is fp < 0.67%. By combining our dataset with the Fischer & Valenti (2005) uniform sample, we confirm that the likelihood of a star to harbor a planet more massive than Jupiter within 2 AU is a steeply rising function of the host's metallicity. However, the data for stars with −1.0≤[Fe/H]≤ 0.0 are compatible, in a statistical sense, with a constant occurrence rate fp≃1%. Our results usefully inform theoretical studies of the process of giant planet formation across two orders of magnitude in metallicity.
Irradiation effects in CO and CO2 ices induced by swift heavy Ni ions at 46 MeV and 537 MeV
Authors: Domaracka A. , Duarte E. Seperuelo , Boduch P. , Rothard H. , Balanzat E. , Dartois E. , Pilling S. , Farenzena L. S. , da Silveira E. F.
Published: March 2010

In order to simulate the effects of the heavy ion component of cosmic rays on ices in astrophysical environments, the CO and CO2 ices were irradiated with swift nickel ions in the electronic energy loss regime. The ices were prepared by condensing gas onto a CsI substrate at a temperature of 14 K and analyzed by means of infrared (FTIR) spectroscopy. The physical process of deposition by Ni ions is similar to more important and abundant heavy cosmic rays such as Fe ions. Dissociation of the ice molecules, and formation of new molecules were observed. Also, sputtering (leading to desorption of molecules from the solid surface to the gas phase) was observed. It was found that the sputtering yield due to heavy ions cannot be neglected with respect to desorption induced by weakly ionizing particles such as UV photons and protons.
Light elements in stars with exoplanets
Authors: Mena E. Delgado , Gálvez-Ortiz M. C. , González-Hernández J. I. , Israelian G. , Santos N. C. , Rebolo R. , Cerdeña C. Dominguez
Published: March 2010

Light elements are important tracers of the internal stellar structure and kinematics. Li and Be are both burned in the stellar interiors but Be requires much higher temperatures and thus we can expect to measure Be abundances in stars which have no detectable Li in their atmospheres. The study of these elements can give us information about processes related to the angular momentum history of these stars, since rotation and angular momentum loss are important mechanisms responsible for the depletion of light elements. Additionally, if pollution has played an important role in determining the high-metal content of planet host stars, we would expect to find a similar or even higher increase in the Li and Be contents. We present Be and Li abundances in a sample of 69 stars with planets and 31 stars without known planetary companion, spanning a large range of effective temperatures.
Photospheric and coronal abundances of solar-type stars with planets: the case of τ Bootis
Authors: Maggio Antonio , Sanz-Forcada Jorge , Scelsi Luigi
Published: March 2010

We present the results of a study of coronal and photospheric abundances in τ Bootis, a middle-aged solar analogue, well known for the presence of a close-in Jovian mass planet. We employ the results of this study, based on high-resolution optical and X-ray spectra, to address the issue of abundance stratification vs. First Ionization Potential (FIP) in the outer stellar atmospheres of solar-type stars with and without planets.
Instrumentation in the ELT era
Authors: Pasquini Luca
Published: March 2010

I review the instrumentation plans of the future ELT projects, with particular emphasys on one category of instruments which will be particularly relevant for this Symposium community: high resolution spectrographs.
How galaxies form: Mass assembly from chemical abundances in the era of large surveys
Authors: Wyse Rosemary F.G.
Published: March 2010

The chemical abundances in the atmosphere of a star provide unique information about the gas from which that star formed, and, modulo processes that are not important for the vast majority of stars, such as mass transfer in close binary systems, are conserved through a star's life. Correlations between chemistry and kinematics have been used for decades to trace dynamical evolution of the Milky Way Galaxy. I discuss how it should be possible to refine and extend such analyses, provided planned large-scale deep imaging surveys have matched spectroscopic surveys.
A Summary and Some Concluding Remarks
Authors: Smith V. V.
Published: March 2010

To present a summary of IAU Symposium 265 it is perhaps best to first step back and ask the question “Why did we meet in Rio to discuss chemical abundances?”. Part of the scientific rationale was to host a meeting that brought together researchers who probe chemical abundances and chemical evolution in all of the different astrophysical environments. All meetings should be planned such that they have an outcome and, with such a diverse set of abundance specialists brought together in one place to talk about their favorite topics, the stated outcome for IAUS265 was to provide, within our current understanding of the universe, a unified picture of the production of chemical elements over cosmic time; such a view is what I think of as cosmochemistry.
The Apache Point Observatory Galactic Evolution Experiment (APOGEE) in Sloan Digital Sky Survey III (SDSS-III)
Authors: Majewski Steven R. , Wilson John C. , Hearty Fred , Schiavon Ricardo R. , Skrutskie Michael F.
Published: March 2010

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) is a large-scale, near-infrared (H-band), high-resolution (R ~ 30,000), high S/N (≳100) spectroscopic survey of Milky Way stellar populations. APOGEE will operate from 1.51–1.68μm, a region that includes useful absorption lines from at least fifteen chemical species including α, odd-Z, and iron peak elements. The APOGEE instrument has a novel design featuring 300 science fibers feeding light to a mosaiced VPH grating and a six-element camera encased in a liquid nitrogen-cooled cryostat. A three year bright-time observing campaign will enable APOGEE to observe approximately 100,000 red giants across the Galactic bulge, disk and halo.
Mirror mode peaks: THEMIS observations versus theories
Authors: Balikhin M. A. , Pokhotelov O. A. , Walker S. N. , Boynton R. J. , Beloff N.
Published: March 2010

Mirror waves have been observed in many different plasma regions within solar system. In contrast to many other plasma waves, mirror mode waves are rarely observed as a quasi‐periodic sinusoidal signature. Mirror structures in the form of magnetic dips are usually observed when the criterion for mirror instability is not satisfied in the plasma surrounding these structures. In contrast, magnetic peaks are observed in mirror unstable plasma. This paper reports on a study of the peak‐type mirror structures in the terrestrial magnetosheath conducted using THEMIS magnetic field and plasma measurements. It is shown that the changes observed in the plasma temperature are inconsistent with the previously shared view that magnetic peaks are nonlinear mirror waves immersed in a background plasma. A model in which the non‐linear mirror waves are composed of a series of peaks and troughs can help to explain the apparent contradictions between theory and observations.
A census of eddy activities in the South China Sea during 1993–2007
Authors: Xiu Peng , Chai Fei , Shi Lei , Xue Huijie , Chao Yi
Published: March 2010

Numerous mesoscale eddies occur each year in the South China Sea (SCS), but their statistical characteristics are still not well documented. A Pacific basin‐wide three‐dimensional physical‐biogeochemical model has been developed and the result in the SCS subdomain is used to quantify the eddy activities during the period of 1993–2007. The modeled results are compared with a merged and gridded satellite product of sea level anomaly by using the same eddy identification and tracking method. On average, there are about 32.9 ± 2.4 eddies predicted by the model and 32.8 ± 3.4 eddies observed by satellite each year, and about 52% of them are cyclonic eddies. The radius of these eddies ranges from about 46.5 to 223.5 km, with a mean value of 87.4 km. More than 70% of the eddies have a radius smaller than 100 km. The mean area covered by these eddies each year is around 160,170 km2, equivalent to 9.8% of the SCS area with water depths greater than 1000 m. Linear relationships are found between eddy lifetime and eddy magnitude and between eddy vertical extent and eddy magnitude, showing that strong eddies usually last longer and penetrate deeper than weak ones. Interannual variations in eddy numbers and the total eddy‐occupied area indicate that eddy activities in the SCS do not directly correspond to the El Niño–Southern Oscillation events. The wind stress curls are thought to be an important but not the only mechanism of eddy genesis in the SCS.
Initial analysis of air temperature and related data from the Phoenix MET station and their use in estimating turbulent heat fluxes
Authors: Davy Richard , Davis Jeffrey A. , Taylor Peter A. , Lange Carlos F. , Weng Wensong , Whiteway Jim , Gunnlaugson Haraldur P.
Published: March 2010

Thermocouples at three levels on a 1 m mast on the deck of the Phoenix Lander provided temperature data throughout the 151 sol Phoenix mission. Air temperatures showed a large diurnal cycle which showed little sol to sol variation, especially over the first 90 sols of the mission. Daytime temperatures at the top (2 m) level typically rose to about 243 K (−30°C) in early afternoon and had large (10°) turbulent fluctuations. These are analyzed and used to estimate heat fluxes. Late afternoon conditions were relatively calm with minimal temperature fluctuations but CFD computations show that heating from the lander deck and instruments have influenced temperatures measured at the lowest level (0.25 m above the deck) on the mast.
TNFRI is a positive T‐cell costimulatory molecule important for the timing of cytokine responses
Authors: Evangelidou Maria , Tseveleki Vivian , Vamvakas Sotiris‐Spyros , Probert Lesley
Published: March 2010

Tumor necrosis factor (TNF)‐ and TNF receptor I (TNFRI)‐deficient mice are resistant to initiation and show delayed resolution of disease in paradigms of autoimmune disease, but the contribution of TNF/TNFRI signaling to T‐cell activation and effector responses has not been determined. In this study, we investigated the role of TNFRI in T‐cell receptor (TCR)‐mediated T‐cell activation in vitro and in vivo using CD3+‐enriched primary T cells and mice deficient in TNFRI. Following TCR engagement, TNFRI knockout (KO) T cells showed significantly delayed proliferation, cell division, upregulation of interleukin 2 (IL‐2) and IL‐2 receptor α chain (CD25) mRNA and cell‐surface expression of CD25 compared with wild‐type (WT) cells. Thus, WT and TNFRI KO cells showed equivalent proliferation peaks at 48 and 72 h, respectively. TNFRI KO mice also developed a defective primary T‐cell response to ovalbumin and an acute contact hypersensitivity response to oxazolone (4‐ethoxymethylene‐2‐phenyl‐2‐oxazolin‐5‐one). However, TNFRI KO splenocytes that were stimulated by TCR engagement in vitro for 96 h produced significantly higher intracellular levels of interferon‐γ (IFN‐γ), IL‐2 and TNF‐α, but not IL‐17, compared with WT cells, in correlation with their relatively higher proliferation rate at this time point. Further, TCR‐stimulated CD3+‐enriched TNFRI KO T cells showed similarly higher production and secretion of IFN‐γ and IL‐2 compared with WT, suggesting that TNFRI‐mediated cytokine regulation might involve a T‐cell autonomous effect. Our results show a novel role for TNFRI as a positive T‐cell costimulatory molecule that is important for timely T‐cell activation and effector cytokine production and the development of primary immune responses in mice.
Revisiting the tolerogenicity of epidermal Langerhans cells
Authors: Lutz Manfred B , Döhler Anja , Azukizawa Hiroaki
Published: March 2010

Langerhans cells (LC) are unique members of the dendritic cell (DC) family residing in the epidermis of skin and mucosa. Specific autocrine and environmental factors shape the biology of LC, such as TGF‐β1, IL‐10, vitamin D3, UV light or neuropeptides, which are required for LC development but also influence their capacity to induce immunity or tolerance. Both, immunogenic and tolerogenic functions require antigen transport from the skin to the draining lymph nodes, but the LC maturation grade directs the differential outcome. In this review, we recapitulate early indications for LC tolerogenicity and oppose them to more recent findings with gene‐targeted mice, which dramatically challenged some of the early results. The newly discovered Langerin+ dermal DC subset (DDC) seems to be responsible also for many tolerogenic effects that were initially attributed to steady state migratory LC. Transfer of antigens from LC to other DC subsets as well as transport of HIV are discussed as part of the complex interactions between LC and other cells or as mechanisms of immune evasion. Finally, the first clinical trials on allergy therapies targeting skin DC in the steady state are mentioned as they may open the door to curative tolerogenic therapies.
Mycobacterium tuberculosis impairs dendritic cell response by altering CD1b, DC‐SIGN and MR profile
Authors: Balboa Luciana , Romero María Mercedes , Yokobori Noemí , Schierloh Pablo , Geffner Laura , Basile Juan I , Musella Rosa M , Abbate Eduardo , de la Barrera Silvia , Sasiain María C , Alemán Mercedes
Published: March 2010

During a chronic infection such as tuberculosis, the pool of tissue dendritic cells (DC) must be renewed by recruitment of both circulating DC progenitors and monocytes (Mo). However, the microenvironment of the inflammatory site affects Mo differentiation. As DC are critical for initiating a Mycobacterium tuberculosis‐specific T‐cell response, we argue that interference of M. tuberculosis with a correct DC generation would signify a mechanism of immune evasion. In this study, we showed that early interaction of γ‐irradiated M. tuberculosis with Mo subverts DC differentiation in vitro. We found that irradiated M. tuberculosis effect involves (1) the loss of a significant fraction of monocyte population and (2) an altered differentiation process of the surviving monocyte subpopulation. Moreover, in the absence of irradiated M. tuberculosis, DC consist in a major DC‐specific intercellular adhesion molecule 3‐grabbing non‐integrin receptor (DC‐SIGNhigh)/CD86low and minor DC‐SIGNlow/CD86high subpopulations, whereas in the presence of bacteria, there is an enrichment of DC‐SIGNlow/CD86high population. Besides, this population enlarged by irradiated M. tuberculosis, which is characterized by a reduced CD1b expression, correlates with a reduced induction of specific T‐lymphocyte proliferation. The loss of CD1molecules partially involves toll‐like receptors (TLR‐2)/p38 MAPK activation. Finally, several features of Mo, which have been differentiated into DC in the presence of irradiated M. tuberculosis, resemble the features of DC obtained from patients with active tuberculosis. In conclusion, we suggest that M. tuberculosis escapes from acquired immune response in tuberculosis may be caused by an altered differentiation into DC leading to a poor M. tuberculosis‐specific T‐cell response.
Topical isoflavonoids reduce experimental cutaneous inflammation in mice
Authors: Bandara Mahesh , Arun Sondur Jayappa , Allanson Munif , Widyarini Sitarina , Chai Zacary , Reeve Vivienne Elizabeth
Published: March 2010

The antioxidant and anti‐proliferative biological effects of isoflavonoids are relevant properties to counteract the characteristics of many cutaneous diseases. This study uses ultraviolet (UV)B irradiation to induce inflammation in the mouse skin, as a model for some symptoms of cutaneous inflammatory and hyperproliferative diseases such as psoriasis in humans, with the objective of testing two topically applied isoflavonoid compounds for therapeutic properties. UVB exposure resulted in the overexpression of the cytokines, tumour necrosis factor (TNF)‐α, interleukin (IL)‐6 and the adhesion molecule P‐cadherin. Infiltration into the dermal compartment of mast cell populations was also induced. These factors are also overexpressed in psoriatic skin. The effect of topical applications of two isoflavonoids, equol and a synthetic analogue NV‐38, was tested. Both isoflavonoids dose dependently inhibited the UVB induction of cutaneous TNF‐α mRNA and protein, a cytokine critical for the initiation of psoriatic inflammation. Expression of IL‐6 mRNA and protein was also decreased, and the number of infiltrating mast cells into the dermis was reduced by both isoflavonoids. Furthermore, the upregulated mRNA and protein levels of P‐cadherin, a marker characteristic of cutaneous hyperproliferation, were also normalized by both isoflavonoids. These results suggest that this class of compounds has the potential for useful, innocuous anti‐inflammatory therapy from topical application in human cutaneous diseases.
Dynamics within the CD95 death‐inducing signaling complex decide life and death of cells
Authors: Neumann Leo , Pforr Carina , Beaudouin Joel , Pappa Alexander , Fricker Nicolai , Krammer Peter H , Lavrik Inna N , Eils Roland
Published: March 2010

This study explores the dilemma in cellular signaling that triggering of CD95 (Fas/APO‐1) in some situations results in cell death and in others leads to the activation of NF‐κB. We established an integrated kinetic mathematical model for CD95‐mediated apoptotic and NF‐κB signaling. Systematic model reduction resulted in a surprisingly simple model well approximating experimentally observed dynamics. The model postulates a new link between c‐FLIPL cleavage in the death‐inducing signaling complex (DISC) and the NF‐κB pathway. We validated experimentally that CD95 stimulation resulted in an interaction of p43‐FLIP with the IKK complex followed by its activation. Furthermore, we showed that the apoptotic and NF‐κB pathways diverge already at the DISC. Model and experimental analysis of DISC formation showed that a subtle balance of c‐FLIPL and procaspase‐8 determines life/death decisions in a nonlinear manner. We present an integrated model describing the complex dynamics of CD95‐mediated apoptosis and NF‐κB signaling.
GINS motion reveals replication fork progression is remarkably uniform throughout the yeast genome
Authors: Sekedat Matthew D , Fenyö David , Rogers Richard S , Tackett Alan J , Aitchison John D , Chait Brian T
Published: March 2010

Previous studies have led to a picture wherein the replication of DNA progresses at variable rates over different parts of the budding yeast genome. These prior experiments, focused on production of nascent DNA, have been interpreted to imply that the dynamics of replication fork progression are strongly affected by local chromatin structure/architecture, and by interaction with machineries controlling transcription, repair and epigenetic maintenance. Here, we adopted a complementary approach for assaying replication dynamics using whole genome time‐resolved chromatin immunoprecipitation combined with microarray analysis of the GINS complex, an integral member of the replication fork. Surprisingly, our data show that this complex progresses at highly uniform rates regardless of genomic location, revealing that replication fork dynamics in yeast is simpler and more uniform than previously envisaged. In addition, we show how the synergistic use of experiment and modeling leads to novel biological insights. In particular, a parsimonious model allowed us to accurately simulate fork movement throughout the genome and also revealed a subtle phenomenon, which we interpret as arising from low‐frequency fork arrest.
Proof of principle for shotgun DNA mapping by unzipping
Authors: Herskowitz Lawrence , Salvagno Anthony , Maloney R. Andy , Le Linh , Koch Steven
Published: March 2010

Ability to map polymerases and nucleosomes on chromatin is important for understanding the impact of chromatin remodeling on key cellular processes. Current methods (such as ChIP and ChIP-chip) have produced a wealth of information that demonstrates this importance, but key information is elusive in these ensemble methods. We’re pursuing a new single-molecule chromatin mapping method based on unzipping native chromatin molecules with optical tweezers. The first step we are taking towards this ability is shotgun DNA mapping (SDM). This is the ability to identify the genomic location of a random DNA fragment based on its naked DNA unzipping forces compared with simulated unzipping forces of a published genome. We show that ~32 separate experimental unzipping curves for pBR322 were correctly matched to their simulated unzipping curves hidden in a background of the ~2700 sequences neighboring XhoI sites in the S. cerevisiae (yeast) genome. We describe this method and characterize its robustness as well as discuss future applications.