bluuebunny/crossref_metadata_2025 huggingface dataset:
Perinatal morbidity and mortality in early‐onset fetal growth restriction: cohort outcomes of the trial of randomized umbilical and fetal flow in Europe (TRUFFLE)
Authors: Lees C. , Marlow N. , Arabin B. , Bilardo C. M. , Brezinka C. , Derks J. B. , Duvekot J. , Frusca T. , Diemert A. , Ferrazzi E. , Ganzevoort W. , Hecher K. , Martinelli P. , Ostermayer E. , Papageorghiou A. T. , Schlembach D. , Schneider K. T. M. , Thilaganathan B. , Todros T. , van Wassenaer‐Leemhuis A. , Valcamonico A. , Visser G. H. A. , Wolf H. ,   the TRUFFLE Group
Published: January 2014

Objectives

Few data exist for counseling and perinatal management of women after an antenatal diagnosis of early‐onset fetal growth restriction. Yet, the consequences of preterm delivery and its attendant morbidity for both mother and baby are far reaching. The objective of this study was to describe perinatal morbidity and mortality following early‐onset fetal growth restriction based on time of antenatal diagnosis and delivery.

Methods

We report cohort outcomes for a prospective multicenter randomized management study of fetal growth restriction (Trial of Randomized Umbilical and Fetal Flow in Europe (TRUFFLE)) performed in 20 European perinatal centers between 2005 and 2010. Women with a singleton fetus at 26–32 weeks of gestation, with abdominal circumference < 10th percentile and umbilical artery Doppler pulsatility index > 95th percentile, were recruited. The main outcome measure was a composite of fetal or neonatal death or severe morbidity: survival to discharge with severe brain injury, bronchopulmonary dysplasia, proven neonatal sepsis or necrotizing enterocolitis.

Results

Five‐hundred and three of 542 eligible women formed the study group. Mean ± SD gestational age at diagnosis was 29 ± 1.6 weeks and mean ± SD estimated fetal weight was 881 ± 217 g; 12 (2.4%) babies died in utero. Gestational age at delivery was 30.7 ± 2.3 weeks, and birth weight was 1013 ± 321 g. Overall, 81% of deliveries were indicated by fetal condition and 97% were by Cesarean section. Of 491 liveborn babies, outcomes were available for 490 amongst whom there were 27 (5.5%) deaths and 118 (24%) babies suffered severe morbidity. These babies were smaller at birth (867 ± 251 g) and born earlier (29.6 ± 2.0 weeks). Death and severe morbidity were significantly related to gestational age, both at study entry and delivery and also with the presence of maternal hypertensive morbidity. The median time to delivery was 13 days for women without hypertension, 8 days for those with gestational hypertension, 4 days for pre‐eclampsia and 3 days for HELLP syndrome.

Conclusions

Fetal outcome in this study was better than expected from contemporary reports: perinatal death was uncommon (8%) and 70% survived without severe neonatal morbidity. The intervals to delivery, death and severe morbidity were related to the presence and severity of maternal hypertensive conditions. Copyright © 2013 ISUOG. Published by John Wiley & Sons Ltd.
Comparison of climate change vulnerability assessments for wildlife
Authors: Lankford Amber J. , Svancara Leona K. , Lawler Joshua J. , Vierling Kerri
Published: January 2014

The need for wildlife climate change vulnerability and sensitivity assessments has increased over the past decade. Use of these assessments by wildlife and land managers has increased due to concern for potential effects of climate change on species and landscapes. Although many approaches exist for assessing sensitivity and vulnerability to climate change, little is known about the similarity of results between methods. We compared outputs of 3 widely available assessments for the western United States: the NatureServe Climate Change Vulnerability Index, the U.S. Forest Service System for Assessing the Vulnerability of Species, and the Climate Change Sensitivity Database. We performed a broad categorical comparison and examined correlations across rankings to compare assessment outputs. We found little agreement in species rankings between pairs of assessments. There is no apparent pattern within, or between, taxa or habitat associations that could explain this poor correlation. Disparities likely result from differences in question format, choice of data input, or how vulnerability or sensitivity is calculated. Consideration of vulnerability quantification is needed, particularly regarding species sensitivity and adaptive capacity, because of limited understanding of species and community responses to climate exposure. Our results indicate it is extremely important to be aware of the specific goal and the quality, quantity, and variety of data used in each individual assessment in order to adequately use these assessments as tools for management planning. With the increasing need to include climate change scenarios in management actions and decisions, we suggest that increased cooperation among assessment developers could greatly aid in eliminating this discrepancy. © 2014 The Wildlife Society
The role of Importin‐βs in the maintenance and lineage commitment of mouse embryonic stem cells
Authors: Sangel Percival , Oka Masahiro , Yoneda Yoshihiro
Published: January 2014

Members of the Importin‐β family recognize nuclear localization signals (NLS) and nuclear export signals (NES). These proteins play important roles in various nucleocytoplasmic transport processes in cells. Here, we examined the expression patterns of 21 identified Importin‐β genes in mouse embryonic stem cells (mESCs), mouse embryonic fibroblast (MEF) and mESCs differentiated into neural ectoderm (NE) or mesoendoderm (ME). We observed striking differences in the Importin‐β mRNA expression levels within these cell types. We also found that knockdown of selected Importin‐β genes led to suppression of Nanog, and altered the balance of Oct4/Sox2 expression ratio, which is important for NE/ME lineage choice. Furthermore, we demonstrated that knockdown of XPO4, RanBP17, RanBP16, or IPO7 differentially affected the lineage selection of differentiating mESCs. More specifically, knockdown of XPO4 selectively stimulated the mESC differentiation towards definitive endoderm, while concomitantly inhibiting NE differentiation. RanBP17 knockdown also promoted endodermal differentiation with no effect on NE differentiation. RanBP16 knockdown caused differentiation into ME, while IPO7 knockdown inhibited NE differentiation, without obvious effects on the other lineages. Collectively, our results suggest that Importin‐βs play important roles in cell fate determination processes of mESCs, such as in the maintenance of pluripotency or selection of lineage during differentiation.
Ebselen induces reactive oxygen species (ROS)‐mediated cytotoxicity in Saccharomyces cerevisiae with inhibition of glutamate dehydrogenase being a target
Authors: Azad Gajendra Kumar , Singh Vikash , Mandal Papita , Singh Prabhat , Golla Upendarrao , Baranwal Shivani , Chauhan Sakshi , Tomar Raghuvir S.
Published: January 2014

Ebselen is a synthetic, lipid‐soluble seleno‐organic compound. The high electrophilicity of ebselen enables it to react with multiple cysteine residues of various proteins. Despite extensive research on ebselen, its target molecules and mechanism of action remains less understood. We performed biochemical as well as in vivo experiments employing budding yeast as a model organism to understand the mode of action of ebselen. The growth curve analysis and FACS (florescence activated cell sorting) assays revealed that ebselen exerts growth inhibitory effects on yeast cells by causing a delay in cell cycle progression. We observed that ebselen exposure causes an increase in intracellular ROS levels and mitochondrial membrane potential, and that these effects were reversed by addition of antioxidants such as reduced glutathione (GSH) or N‐acetyl‐l‐cysteine (NAC). Interestingly, a significant increase in ROS levels was noticed in gdh3‐deleted cells compared to wild‐type cells. Furthermore, we showed that ebselen inhibits GDH function by interacting with its cysteine residues, leading to the formation of inactive hexameric GDH. Two‐dimensional gel electrophoresis revealed protein targets of ebselen including CPR1, the yeast homolog of Cyclophilin A. Additionally, ebselen treatment leads to the inhibition of yeast sporulation. These results indicate a novel direct connection between ebselen and redox homeostasis.
Black soyabean seed coat extract regulates iron metabolism by inhibiting the expression of hepcidin
Authors: Mu Mingdao , Wu Aimin , An Peng , Du Xiaoli , Wu Qian , Shen Xiaoyun , Wang Fudi
Published: January 2014

Hepcidin, a key regulator of Fe homeostasis, is an ideal drug target for treating patients with Fe disorders such as haemochromatosis, anaemia of chronic inflammation and Fe-deficiency anaemia. However, whether (and how) traditional Chinese black foods (e.g. black soyabeans) target hepcidin and improve Fe-deficiency anaemia remains unclear. Herein, we report that black soyabean seed coat extract (BSSCE) can potently inhibit thein vitroandin vivoexpression of hepcidin. In the present study, in cells treated with 200 μg/ml BSSCE, hepcidin expression was found to be reduced to only 6 % of the control levels (P< 0·01). An AIN-76A diet containing 2 % BSSCE was fed to 8-week-old male C57BL/6 mice for 0, 1, 7, 15 or 30 d; importantly, compared with the day 0 group, the day 7 group exhibited nearly a 50 % decrease in hepatic hepcidin expression (P< 0·01), a 35 % decrease in splenic Fe concentrations (P< 0·05) and a 135 % increase in serum Fe concentrations (P< 0·05). Mechanistically, the effect of BSSCE on hepcidin expression was mediated via a reduction in the phosphorylation levels of mothers against decapentaplegic homolog proteins (Smad)1/5/8. Consequently, the mice in the day 30 group exhibited large increases in erythrocyte counts (111 %v.day 0,P< 0·01), Hb concentrations (109 %,P< 0·01) and haematocrit values (108 %,P< 0·01). In conclusion, these results indicate that black soyabean extract regulates Fe metabolism by inhibiting the expression of hepcidin. This finding can be used to optimise the intervention of patients with hepcidin-related diseases, including Fe-deficiency anaemia.
In Search of Power: The European Commission in the Kennedy Round Negotiations (1963–1967)
Authors: COPPOLARO LUCIA
Published: January 2014

This article is about EEC trade policy-making in the GATT Kennedy Round negotiations. It questions whether the European Commission was decisive in terms of reaching an agreement in Brussels and then in Geneva, and whether the final outcome resembled the Commission's preferences. The article shows that in Brussels the Commission was able to make its preferences prevail only when these appealed to the Council of Ministers. In Geneva, member states pragmatically set limits to the actions of the Commission, guided by the principle of how they could enhance their trade interests. Eventually, they allowed the Commission to strengthen its role because this was in line with their interests.
Ambiguities, Fractures and Myopic Histories: Recent work on German Minorities in Twentieth-Century Eastern Europe
Authors: PENNY H. GLENN
Published: January 2014

Germans have long been part of the multi-ethnic and multicultural histories that shaped the territory between the Oder and the Urals. The presence of Germans, however, was seldom the same as ‘a German presence’ nor has it always been clear who the ‘Germans’ might be, or might have been. During the medieval period, for example, as Roger Bartlett and Karen Schönwälder reminded us more than a decade ago, a German in eastern Europe ‘might be one who came from a core German territory, spoke a Germanic language, or to whom German law applied; but none of these criteria was necessarily decisive or historically unambiguous’. That equivocality proved tenacious, and consequently the clichéd polarity of Teuton and Slav has frequently obscured the ‘fluidity of identity and multiplicity of interaction’ that remain ‘crucial’ to understanding the history of this region, where ‘impulses of culture, religion, political and economic interest, whether uniting or dividing, have often cut across linguistic or ethnic differences’.
Detailed Studies of the Sculptor Dwarf Spheroidal Galaxy in the Milky Way halo
Authors: Tolstoy Eline
Published: January 2014

In and around the Milky Way halo there are a number of low mass low luminosity dwarf galaxies. Several of these systems have been studied in great detail. I describe recent photometric and spectroscopic studies of the Sculptor dwarf spheroidal galaxy made as part of the DART survey of nearby dwarf spheroidal galaxies.
Chemical differences and similarities among the kinematically selected thick disk, inner halo and outer halo stars
Authors: Ishigaki Miho N. , Aoki Wako , Chiba Masashi
Published: January 2014

Chemical diversity among metal-poor stars in the old stellar components in the Milky Way (MW), namely the thick disk and stellar halo, provides clues to understanding the early chemodynamical evolution of our Galaxy. We present our results on a homogeneous chemical abundance analysis for nearby metal-poor stars likely belonging to the MW thick disk, inner and outer stellar halos. Abundances of alpha, sodium, iron-peak and neutron-capture elements in the sample stars have been estimated using high-resolution (R 50000) spectra obtained with the High Dispersion Spectrograph mounted on the Subaru Telescope. The derived abundances are used to examine differences and similarities in elemental abundance ratios among the kinematically defined thick disk, inner and outer halo subsamples in the metallicity range of −3.3 < [Fe/H] < −0.5. We show that, in the metallicity range of [Fe/H] < −2, the three subsamples are similar in most of the elemental abundances. On the other hand, in the higher metallicities, particularly in [Fe/H] > −1.5, the thick disk and the inner/outer halo subsamples show systematically different abundance ratios for some elements including alpha, sodium, zinc and europium. A modest difference in the sodium and zinc abundances between the inner- and outer halo subsamples is also identified. The observed distinct abundances of some elements among the three subsamples implies that their constituent stars originally formed in progenitor systems that have experienced different star formation and chemical enrichment histories.
MilkyWay@home: Harnessing volunteer computers to constrain dark matter in the Milky Way
Authors: Newberg Heidi Jo , Newby Matthew , Desell Travis , Magdon-Ismail Malik , Szymanski Boleslaw , Varela Carlos
Published: January 2014

MilkyWay@home is a volunteer computing project that allows people from every country in the world to volunteer their otherwise idle processors to Milky Way research. Currently, more than 25,000 people (150,000 since November 9, 2007) contribute about half a PetaFLOPS of computing power to our project. We currently run two types of applications: one application fits the spatial density profile of tidal streams using statistical photometric parallax, and the other application finds the N-body simulation parameters that produce tidal streams that best match the measured density profile of known tidal streams. The stream fitting application is well developed and is producing published results. The Sagittarius dwarf leading tidal tail has been fit, and the algorithm is currently running on the trailing tidal tail and bifurcated pieces. We will soon have a self-consistent model for the density of the smooth component of the stellar halo and the largest tidal streams. The N-body application has been implemented for fitting dwarf galaxy progenitor properties only, and is in the testing stages. We use an Earth-Mover Distance method to measure goodness-of-fit for density of stars along the tidal stream. We will add additional spatial dimensions as well as kinematic measures in a piecemeal fashion, with the eventual goal of fitting the orbit and parameters of the Milky Way potential (and thus the density distribution of dark matter) using multiple tidal streams.
Stellar yields for chemical evolution modelling
Authors: Karakas Amanda I.
Published: January 2014

Stellar yields are a key ingredient in chemical evolution models. Stars with masses as low as 0.9M⊙, which have an age less than that of our Galaxy at low metallicity, can contribute to the chemical evolution of elements. Stars less than about 8–10M⊙ experience recurrent mixing events that can significantly change the surface composition of the envelope. Evolved stars are observed with surface enrichment in carbon, nitrogen, fluorine, and heavy elements synthesized by the slow neutron capture process (the s-process). These stars release their nucleosynthesis products through stellar outflows or winds, in contrast to massive stars that explode as core-collapse supernovae. Here I review stellar yields for stars up to 10M⊙, including a brief discussion of their uncertainties and shortcomings. Finally, I discuss efforts by various groups to address these issues and to provide homogeneous yields for low and intermediate-mass stars covering a broad range of metallicities.
Supernova Yields for Chemical Evolution Modeling
Authors: Nomoto Ken'ichi , Suzuki Tomoharu
Published: January 2014

We review the recent results of the nucleosynthesis yields of massive stars. We examine how those yields are affected by some hydrodynamical effects during the supernova explosions, namely, explosion energies from those of hypernovae to faint supernovae, mixing and fallback of processed materials, asphericity, etc. Those parameters in the supernova nucleosynthesis models are constrained from observational data of supernovae and metal-poor stars. The elemental abundance patterns observed in extremely metal-poor stars show some peculiarities relative to the solar abundance pattern, which suggests the important contributions of hypernovae and faint supernovae in the early chemical enrichment of galaxies. These constraints on supernova nucleosynthesis are taken into account in the latest yield table for chemical evolution modeling.
Stream-orbit misalignment & a new algorithm for constraining the Galactic potential with streams
Authors: Sanders Jason L. , Binney James
Published: January 2014

In general, a tidal stream is misaligned with the orbit of its progenitor. Here we present the formation of tidal streams in angle-action space to discuss the effect of this misalignment on orbit-fitting algorithms for constraining the Galactic potential. We close by presenting and testing an alternative algorithm which more fully accounts for the dynamics of streams by using the angle-action formalism.
Action-space clustering of tidal streams to map the Galactic potential
Authors: Sanderson Robyn E. , Helmi Amina , Hogg David W.
Published: January 2014

Given a parametrized model of the Galactic potential, the best-fit parameters can be obtained by maximizing the Kullback-Leibler divergence of the action distribution of a set of stars initially clustered in action space (e.g. stars in tidal streams). This method will allow us to map the Milky Way's gravitational potential by simultaneously fitting multiple tidal streams without requiring stream membership information. With 20 streams of at least 20 stars each, including observational errors consistent with predictions for Gaia, this technique recovers the input potential parameters to a precision of 10-60% and an accuracy of 10%. With all the observed streams in our mock stellar halo (about 40) that fit the error criteria, the precision improves to 10%.
How can star formation be sustained?
Authors: Fraternali Filippo
Published: January 2014

There is overwhelming evidence that the Milky Way has formed its stars at a relatively constant rate throughout the Hubble time. This implies that its stock of cold gas was not in place since the beginning but it has been acquired slowly through gas accretion. The gas accretion must have been at low metallicity in order to reconcile the metallicities observed in the disc with the predictions of chemical evolution models. But how does this gas accretion take place? I review the current evidence of gas accretion into the Milky Way and similar galaxies through the infall of cold gas clouds and satellites. The conclusion from these studies is that the infalling gas at high column densities observed in HI emission is a least one order of magnitude below the value required to sustain star formation, thus accretion must come from a different channel. The likely reservoir for gas accretion is the cosmological corona of virial-temperature gas in which every galaxy must be embedded. At the interface between the disc and the corona the cold high-metallicity disc gas and the hot coronal medium must mix efficiently and this mixing causes the cooling and accretion of the lower corona. I show how this mechanism reproduces the kinematics of the neutral extraplanar gas in the Milky Way and other nearby galaxies and the ionised high-velocity clouds observed in HST spectra. I conclude with the speculation that the loss in efficiency of the disc-corona interaction is the ultimate cause for the evolution of disc galaxies towards the red sequence.
LAMOST Experiment on Galactic Understanding and Exploration: An overview
Authors: Deng Licai
Published: January 2014

The LAMOST survey of the Galaxy, otherwise named LEGUE (LAMOST Experiment for Galactic Understanding and Exploration) started in October 2012. In this talk, I will give an overview of the science plan and the current status of the survey.
LSS-GAC – A LAMOST Spectroscopic Survey of the Galactic Anti-center
Authors: Liu X.-W. , Yuan H.-B. , Huo Z.-Y. , Deng L.-C. , Hou J.-L. , Zhao Y.-H. , Zhao G. , Shi J.-R. , Luo A.-L. , Xiang M.-S. , Zhang H.-H. , Huang Y. , Zhang H.-W.
Published: January 2014

As a major component of the LAMOST Galactic surveys, the LAMOST Spectroscopic Survey of the Galactic Anti-center (LSS-GAC) will survey a significant volume of the Galactic thin/thick disks and halo in a contiguous sky area of ~3,400 sq.deg., centered on the Galactic anti-center (|b| ≤ 30°, 150 ≤ l ≤ 210°), and obtain λλ3800–9000 low resolution (R ~1,800) spectra for a statistically complete sample of ≳ 3 M stars of all colors, uniformly and randomly selected from (r, g - r) and (r, r - i) Hess diagrams obtained from a CCD imaging photometric survey of ~5,400 sq.deg. with the Xuyi 1.04/1.20 m Schmidt Telescope, ranging from r = 14.0 to a limiting magnitude of r = 17.8 (18.5 for limited fields). The survey will deliver spectral classification, radial velocity (Vr) and stellar parameters (effective temperature (Teff), surface gravity (log g) and metallicity [Fe/H]) for millions of Galactic stars. Together with Gaia which will provide accurate distances and tangential velocities for a billion stars, the LSS-GAC will yield a unique data set to study the stellar populations, chemical composition, kinematics and structure of the disks and their interface with the halo, identify streams of debris of tidally disrupted dwarf galaxies and clusters, probe the gravitational potential and dark matter distribution, map the 3D distribution of interstellar dust extinction, search for rare objects (e.g. extremely metal-poor or hyper-velocity stars), and ultimately advance our understanding of the assemblage of the Milky Way and other galaxies and the origin of regularity and diversity of their properties.

The survey was initiated in the fall of 2012 and expected to complete in the spring of 2017. Hitherto, about 0.4 M spectra of S/N(λ7450) ≥ 10 per pixel have been accumulated. In addition, bright nights have been used to target stars brighter than 14 mag and have so far generated over 0.4 M spectra, yielding an excellent sample of local stars to probe the solar neighborhood. LSP3, a set of pipelines tailored to the need of LSS-GAC, for spectral flux-calibration, and radial velocity and stellar parameter determinations, have been developed at Peking University, based on packages developed for the SDSS and those at the National Astronomical Observatories of Chinese Academy of Sciences. Comparisons of multi-epoch observations, with the SDSS results, as well as applying the pipelines to open and globular clusters show that LSP3 has achieved a precision of 5 km s−1, 110 K, 0.15 dex and 0.15 dex for Vr, Teff, log g and [Fe/H], respectively. The data are publicly available, subject to regulations of the LAMOST data policy, and begin to yield scientific results. The potential of LSS-GAC and power of existing data are illustrated with examples of selected problems.
The Sun. A typical star in the solar neighborhood?
Authors: Meléndez Jorge
Published: January 2014

The Sun is used as the fundamental standard in chemical abundance studies, thus it is important to know whether the solar abundance pattern is representative of the solar neighborhood. Albeit at low precision (0.05 – 0.10 dex) the Sun seems to be a typical solar-metallicity disk star, at high precision (0.01 dex) its abundance pattern seems abnormal when compared to solar twins. The Sun shows a deficiency of refractory elements that could be due to the formation of terrestrial planets. The formation of giant planets may also introduce a signature in the chemical composition of stars. We discuss both planet signatures and also the enhancement of neutron-capture elements in the solar twin 18 Sco.
Abundance analysis of three metal poor stars: CS 22166-0030, CS 22186-0005, and CS 30344-0033
Authors: Çalışkan Şeyma , Caffau Elisabetta , Bonifacio Piercarlo , Sbordone Luca , Albayrak Berahitdin
Published: January 2014

We present the abundance analysis of three very metal poor stars, CS 22166-0030 ([Fe/H]=−2.96), CS 22186-0005 ([Fe/H]=−2.70), and CS 30344-0033 ([Fe/H]=−2.90). Our study is based on high resolution spectra which were obtained from SARG (on TNG), HARPS (on 3.6m), and UVES (on VLT) spectrographs and one-dimensional ATLAS9 model atmospheres. We derived the abundances for 2, 9, and 16 atomic species in the spectrum of CS 22166-0030, CS 22186-0005, and CS 30344-0033, respectively. The Na and Mg abundances of CS 22166-0030 are highly under-abundant with respect to the solar values. The abundance patterns of CS 22186-0005 and CS 30344-0033 are consistent with the other halo stars within abundance uncertainties.
Influence of Departures from LTE on Oxygen Abundance Determination in the Atmospheres of A – K stars
Authors: Sitnova Tatyana , Mashonkina Lyudmila , Zhao Gang , Ryabchikova Tatiana , Pakhomov Yury
Published: January 2014

Solar oxygen abundance is a key parameter for the studies of solar physics. Oxygen abundances of cool stars with different metallicities are important for understanding the galactic chemical evolution. We present non-LTE calculations for O I with the classical plane-parallel (1D) model atmospheres for a set of stellar parameters corresponding to stars of spectral types from A to K. Non-LTE leads to strengthening the O I lines, and the difference between the non-LTE and LTE abundances (non-LTE correction) is negative. The departures from LTE grow toward higher effective temperature and lower surface gravity. In the entire temperature range and log g = 4, the non-LTE correction does not exceed 0.05 dex in absolute value for lines of O I in the visible spectral range. The non-LTE corrections are significantly larger for the infrared O I 7771-5, 8446 Å lines and reach an order of magnitude for A-type stars. To differentiate the effects of inelastic collisions with electrons and neutral hydrogen atoms on the statistical equilibrium (SE) of O I, we derived the oxygen abundance for the five well studied A-type stars. For each star, non-LTE largely removes the difference between the infrared and visible lines found in LTE. In the case of cool stars (Sun and Procyon), inelastic collisions with H I affect the SE of O I, and agreement between the abundances from different lines is achieved when using the Drawin's formalism for collisional rates calculations. The solar mean oxygen abundance from the six lines is ϵ = 8.74 ± 0.05, when using the MAFAGS-OS solar model atmosphere and ϵ = 8.78 ± 0.03, when applying the 3D corrections taken from the literature. The non-LTE abundances of oxygen are derived for the sample of cool dwarfs with various metallicities on high-resolution spectra observed in the Lick observatory.
The Correction of Fiber Throughput Variation due to Focal Ratio Degradation
Authors: Chen Jianjun , Bai Zhongrui , Li Guangwei , Zhang Haotong
Published: January 2014

The focal ratio degradation (FRD) of optical fibers is a major source causing light loss to astronomical multi-fibre instruments like LAMOST (Oliveira, A. C, et al. 2005). The effects of stress and twist during mounting and rotation of the fibers could change the FRD for individual fibers (Clayton 1989), which means that the transmission efficiency of each individual fiber will vary. We investigate such throughput variation among LAMOST fibers and its relevance to the intensity of sky emission lines (Garstang 1989) over the full wavelength coverage. On the basis of the work, we present an approach to correct the varied fiber throughput by measuring the strength of the sky emission lines as the secondary throughput correction.
Fiber Positioning Test
Authors: Dong Yiqiao , Zhang Haotong , Bai Zhongrui , Yuan Hailong , Lei Yajuan
Published: January 2014

With the concern that observed flux is very sensitive upon fiber positions, we develop a novel approach measuring the error of fiber positions in this work. More specifically, we compute two orthogonal groups of the flux ratio before and after moving the fiber a few arcseconds, and correct the system coordinate transformation based on the computed fiber position error.
Weak Atomic Diffusion Trends in NGC 6752
Authors: Gruyters Pieter , Korn Andreas J. , Barklem Paul S.
Published: January 2014

Atomic diffusion (AD) is a slow continuous process that depletes heavy elements such as Fe from the surface layers during the MS lifetime of a star. As the star evolves to the RGB the effect of depletion disappears as its deep outer convection zone restores the original composition in the atmosphere. Mixing processes at work below the outer convection zone reduce the effect of AD as they hinder the downward diffusion of heavy elements, and thus a more efficient mixing will cause flattened diffusion trends. Such additional mixing (AddMix) seems to be needed to reproduce observed abundance trends. Although the inclusion of extra mixing in a layer just below the convective envelope is remarkably successful in describing the observed abundance trends in NGC 6397 ([Fe/H] = −2.1), the description applied is in no way unique or physically satisfying. To better understand the physics and place additional constraints on the possible variation of extra mixing with stellar parameters such as metallicity, we conducted a study, similar to that presented in Korn et al. (2007), of another metal-poor GC NGC 6752 ([Fe/H] = −1.6). In Fig. 1 we show the results, published in Gruyters et al. (2013), which shows weak yet systematic abundance trends with evolutionary phase for Fe, Sc, Ti and Ca. The trends are best explained by stellar structure models including AD with efficient AddMix. As a consequence sub-primordial stellar lithium abundances of the stars on the Spite plateau can be brought up to match the WMAP-calibrated Big Bang nucleosynthesis predictions to within the mutual 1-sigma errors.
Strontium in the era of Gaia and LAMOST
Authors: Hansen Camilla J. , Caffau Elisabetta , Bergemann Maria
Published: January 2014

The formation and evolution of the heavy neutron-capture elements (Z > 37) are to date not well understood. Therefore, abundance and galactic chemical evolution (GCE) studies of these heavy elements may carry key information to this open question. Strontium (Sr) is one of the two heavy elements (Sr and Ba) that show intrinsically very strong absorption lines even in extremely metal-poor stars (and remains detectable at low spectral resolution). Hence, the 4077 Å Sr II line provides a unique insight into the behaviour of heavy neutron-capture elements at all metallicities and resolutions. Here the focus is on strontium, its 3D and NLTE (non-local thermodynamic equilibrium) corrections, as well as chemical evolution.
Symbiotic stars as tracers of Galactic structures
Authors: Leedjärv L.
Published: January 2014

The Gaia mission is expected to provide a total number of symbiotic stars in the Galaxy and their membership in stellar populations. Symbiotic stars with distinct emission lines in their spectra can be used as test objects in the analysis of Gaia data on peculiar stars.
The methods for searching hypervelocity star candidates from the SDSS
Authors: Li Yinbi , Luo Ali , Zhao Gang , Lu Youjun
Published: January 2014

Hyper-velocity stars are believed to be ejected out from the Galactic center through dynamical interactions of (binary) stars with the central massive black hole(s). In this paper, we firstly select F and G type main sequence stars from about 370,000 stellar spectra of DR7. Then, we select 369 high velocity stars from main sequence samples using the radial velocity distribution. Finally, we find 13 possible unbound hyper-velocity star candidates from the 369 high velocity stars.
The photometric system of the Nanshan One-meter Wide field Telescope
Authors: Liu Jinzhong , Zhang Yu , Feng Guojie , Bai Chunhai
Published: January 2014

A one-meter wide field astronomical telescope with Alt-Az mount, putting in work at prime focus with field corrector, is located at the Nanshan site of Xinjiang Astronomical Observatory. The Nanshan One meter Wide-field Telescope (hereafter NOWT) provides excellent optical quality, pointing accuracy and tracking accuracy. The main scientific goals of NOWT are supernovae, gamma-ray bursts, novae, variable stars, and active galactic nuclei. It is worthwhile to point out that the sky background at the Nanshan is a classic optical site.
The stellar metallicity distribution of the Galaxy from the BATC survey
Authors: Peng Xiyan , Du Cuihua , Wu Zhenyu , Ma Jun , Zhou Xu
Published: January 2014

Using ~2200 BATC main sequence (MS) stars which include SDSS stellar atmospheric parameters, we develop the polynomial photometric calibration method to evaluate the stellar effective temperature and metallicity for BATC data. This calibration method has been applied to about 160 000 MS stars. The mean stellar metallicity smoothly decreases from −0.65 to −0.78 dex in the interval 0.5 < |Z| ≤ 2 kpc. Metallicity distributions in the halo and the thick disk seem invariant with the distance from the Galactic plane.
The SED Machine - Fast classification of transient objects
Authors: Ritter Andreas , Konidaris N. , Ngeow C. C. , Quimby R. , Ben-Ami S.
Published: January 2014

The field of time-domain astronomy is expected to enjoy a golden age during this decade. However, the traditional method for the classification of transient candidates using spectra obtained with medium- to large-aperture telescopes is extremely time consuming and struggling to keep up with the discovery rate. The Spectral Energy Distribution (SED) Machine uses a new approach in order to overcome this shortcoming.
Relations of stellar mass and electron temperature-based metallicity of star-forming galaxies in wide mass range
Authors: Shi Weibin , Liang Yanchun , Hammer Francois
Published: January 2014

We gather a sample of both metal-rich and low metallicity galaxies. Both of them have oxygen abundances estimated from electron temperature (Te). They spread in a wide stellar mass range from 106M⊙ to 1011M⊙. Then, a consistent relation of stellar mass and metallicity are derived from them for such wide range of stellar masses. This relation also shows clearly the discrepancy of Te-based oxygen abundances from those derived from the strong-line method.
Measuring Stellar Radial Velocity using Markov Chain Monte Carlo(MCMC) Method
Authors: Song Yihan , Luo Ali , Zhao Yongheng
Published: January 2014

Stellar radial velocity is estimated by using template fitting and Markov Chain Monte Carlo(MCMC) methods. This method works on the LAMOST stellar spectra. The MCMC simulation generates a probability distribution of the RV. The RV error can also computed from distribution.
Error Analysis of SDSS/LAMOST Stellar Radial Velocity Measurement
Authors: Wang Fengfei , Luo Ali , Zhang Haotong
Published: January 2014

We select super high quality spectra of spectral type A, F, G, K, M stars from SDSS C DR7. We mix our spectra with noise and then measure their radial velocity. The analysis shows that the accuracy of K, M type stars is much better than A, F stars. With our relationship between the signal-to-noise and accuracy of radial velocity measurement of different spectral type, we provide a good reference for stellar study related to radial velocity.
Spin-Orbit Angles as a Probe to Orbital Evolution
Authors: Triaud A. H. M. J. , Cameron A. Collier , Queloz D. , Anderson D. R. , Brown D. J. A. , Smalley B. , Bouchy F. , Lendl M. , Gillon M.
Published: January 2014

We observed with HARPS, the Rossiter-McLaughlin effect for 40 of the 75 transiting hot Jupiters discovered in the Southern Hemisphere by WASP. Our observations reveal a wide distribution in orbital inclinations indicative of past dynamical interactions. Our data also demonstrate the important effect produced by tidal interactions in shaping the spin–orbit (β) angle distribution. We briefly present and interpret the data we collected in a series of graphs.
Results of the NaCo Large Program: probing the occurrence of exoplanets and brown dwarfs at wide orbit
Authors: Vigan A. , Chauvin G. , Bonavita M. , Desidera S. , Bonnefoy M. , Mesa D. , Beuzit J.-L. , Augereau J.-C. , Biller B. , Boccaletti A. , Brugaletta E. , Buenzli E. , Carson J. , Covino E. , Delorme P. , Eggenberger A. , Feldt M. , Hagelberg J. , Henning T. , Lagrange A.-M. , Lanzafame A. , Ménard F. , Messina S. , Meyer M. , Montagnier G. , Mordasini C. , Mouillet D. , Moutou C. , Mugnier L. , Quanz S. P. , Reggiani M. , Ségransan D. , Thalmann C. , Waters R. , Zurlo A.
Published: January 2014

Over the past decade, a growing number of deep imaging surveys have started to provide meaningful constraints on the population of extrasolar giant planets at large orbital separation. Primary targets for these surveys have been carefully selected based on their age, distance and spectral type, and often on their membership to young nearby associations where all stars share common kinematics, photometric and spectroscopic properties. The next step is a wider statistical analysis of the frequency and properties of low mass companions as a function of stellar mass and orbital separation. In late 2009, we initiated a coordinated European Large Program using angular differential imaging in the H band (1.66 μm) with NaCo at the VLT. Our aim is to provide a comprehensive and statistically significant study of the occurrence of extrasolar giant planets and brown dwarfs at large (5-500 AU) orbital separation around ~150 young, nearby stars, a large fraction of which have never been observed at very deep contrast. The survey has now been completed and we present the data analysis and detection limits for the observed sample, for which we reach the planetary-mass domain at separations of ≳50 AU on average. We also present the results of the statistical analysis that has been performed over the 75 targets newly observed at high-contrast. We discuss the details of the statistical analysis and the physical constraints that our survey provides for the frequency and formation scenario of planetary mass companions at large separation.
Quick-MESS: A fast statistical tool for Exoplanet Imaging Surveys
Authors: Bonavita Mariangela , De Mooij Ernst , Jayawardhana Ray , Gratton Raffaele
Published: January 2014

Several tools have been developed for the analysis of the results of direct imaging exoplanet surveys, mostly using a combination of Monte-Carlo simulations or a Bayesian approach. Here we present a novel approach to the statistical analysis of Direct Imaging surveys, called Quick-MESS, which allows for a much faster and flexible analysis.
GRAPHIC: The Geneva Reduction and Analysis Pipeline for High-contrast Imaging of planetary Companions
Authors: Hagelberg Janis , Ségransan Damien , Udry Stéphane , Wildi François
Published: January 2014

We present a new analysis and reduction pipeline for the detection of planetary companions using Angular Differential Imaging. The pipeline uses Fourier transforms for image shifting and rotation in order to achieve very low signal loss. Furthermore it is parallelised in order to run on computer clusters of up to 1024 cores. The pipeline was developed in Geneva for the ongoing direct imaging campaign for stars with radial velocity drifts in the HARPS and CORALIE radial-velocity planet-search surveys. In addition to that, a disk mode has been implemented in the context of observations of the protoplanetary disk around HD142527.
TLOCI: A Fully Loaded Speckle Killing Machine
Authors: Marois Christian , Correia Carlos , Véran Jean-Pierre , Currie Thayne
Published: January 2014

A new high-contrast imaging subtraction algorithm (TLOCI) is presented to maximize a planet signal-to-noise ratio. The technique uses an input spectrum and template PSFs to optimize the reference image coefficient determination to minimize the flux contamination via self-subtraction (thus maximizing its throughput wavelength per wavelength) of any planet that have a similar spectrum to the template spectrum in the image, while trying, at the same time, to maximize the speckle noise subtraction. The optimization is performed by a correlation matrix conditioning. Using laboratory Gemini Planet Imager data, the new algorithm is shown to be superior to the simple/double difference, polynomial fit and original LOCI algorithm.
Exploring exoplanetary systems beyond 1AU with WFIRST
Authors: Penny Matthew T. , Gaudi B. Scott
Published: January 2014

The Wide Field InfraRed Survey Telescope (WFIRST) was the top ranked large space mission of the New Worlds, New Horizons Decadal Survey, and is currently under active study by NASA. Its primary instrument will be a large-format high-resolution near-infrared imager and slitless spectrometer. A primary goal of WFIRST will be to perform a high-cadence microlensing survey of the Galactic bulge to search for low-mass exoplanets beyond the ice line. We highlight some of the expected results of the WFIRST exoplanet survey. For example, the survey will probe the abundance of Earth-mass planets from less than 1 AU outwards, including free-floating planets. In its peak sensitivity range of ~2–5 AU, WFIRST will be sensitive to planets with masses lower than Mercury, and even down to the mass of Ganymede. Overall, WFIRST is expected to detect several thousand bound planets, in addition to several thousand free-floating planets. WFIRST will complete the exoplanet census begun by Kepler, enabling an unprecedented understanding of planetary systems and their formation.
Campaign Scheduling and Analysis for the Gemini Planet Imager
Authors: Savransky Dmitry , Macintosh Bruce A. , Graham James , Konopacky Quinn M. ,   the GPI science team
Published: January 2014

The Gemini Planet Image (GPI) is a new, high-contrast, exoplanet-imaging, facility instrument for the Gemini South observatory, scheduled to begin science observations in 2014. The GPI Exoplanet Survey (GPIES) has been awarded 890 hours to image and spectrally and polarimetrically characterize young, giant planets within 100 parsecs of the solar system. In preparation for the survey, we have developed a framework for simulating GPI observations and generating end-to-end survey simulations. We present new extensions to this modeling effort and our latest results. We discuss systematic methods for scheduling the survey to ensure that the population of discovered planets is useful in constraining formation models and possibly distinguishing between gravitational collapse and core accretion as the primary formation mechanism.
The VLTi/PIONIER survey of southern TTauri disks
Authors: Anthonioz Fabien , Ménard F. , Pinte C. , Thi W-F. , Lebouquin J.-B. , Berger J.-P. , Benisty M. , Absil O. , Duchène G. , Lazareff B. , Malbet F. , Millan-Gabet R. , Traub W. , Zins G.
Published: January 2014

Studying the inner regions of protoplanetary disks (1-10 AU) is of importance to understand the formation of planets and the accretion process feeding the forming central star. Herbig AeBe stars are bright enough to be routinely observed by Near IR interferometers. The data for the fainter T Tauri stars is much more sparse. In this contribution we present the results of our ongoing survey at the VLTI. We used the PIONIER combiner that allows the simultaneous use of 4 telescopes, yielding 6 baselines and 3 independent closure phases at once. PIONIER's integrated optics technology makes it a sensitive instrument. We have observed 22 T Tauri stars so far, the largest survey for T Tauri stars to this date.

Our results demonstrate the very significant contribution of an extended component to the interferometric signal. The extended component is different from source to source and the data, with several baselines, offer a way to improve our knowledge of the disk geometry and/or composition. These results validate an earlier study by Pinte et al. 2008 and show that the dust inner radii of T Tauri disks now appear to be in better agreement with the expected position of the dust sublimation radius, contrary to previous claims.
TW Hydrae: multi-wavelength interferometry of a transition disk
Authors: Menu J. , van Boekel R. , Henning T. , Benisty M. , Chandler C. J. , Linz H. , Waelkens C. , Andrews S. M. , Calvet N. , Carpenter J. M. , Corder S. A. , Deller A. T. , Dullemond C. P. , Greaves J. S. , Harris R. J. , Isella A. , Kwon W. , Lazio J. , Mundy L. G. , Perez L. M. , Ricci L. , Sargent A. I. , Storm S. , Testi L. , Wilner D. J.
Published: January 2014

For over a decade, the structure of the inner “hole” in the transition disk around TW Hydrae has been a subject of debate. To probe the innermost regions of the protoplanetary disk, observations at the highest possible spatial resolution are required. We present new interferometric data of TW Hya from near-infrared to millimeter wavelengths. We confront existing models of the disk structure with the complete data set and develop a new, detailed radiative-transfer model. This model is characterized by: 1) a spatial separation of the largest grains from the small disk grains; and 2) a smooth inner rim structure, rather than a sharp disk edge.
Probing planet nurseries with rare isotopologues of CO
Authors: Dodson-Robinson Sarah E. , Yu Mo , Willacy Karen
Published: January 2014

The properties of planet-forming midplanes of protostellar disks remain largely unprobed by observations due to the high optical depths of common molecular lines. However, rotational emission lines from rare isotopologues may have optical depth near unity in the vertical direction, so that the lines are strong enough to be detected, yet remain transparent enough to trace the disk midplane. We have computed chemical models of protostellar disks including different C and O isotopes and detailed photochemical reactions. The CO condensation front is in the giant planet-forming region, within 20 AU of the star. We show that the optical depths of low-order rotational lines of C17O are around unity, which suggests that it may be possible to see into the disk midplane using C17O. In lower-mass disks, the slightly more abundant C18O is a possible midplane probe. ALMA observations would provide estimates of the disk midplane temperature if CO ice line were spatially resolved. With our computed C17O/H2 abundance ratio, we would also be able to measure disk surface densities from the fluxes of low-order C17O transitions.
Can a planet explain different cavity sizes for small & large dust grains in transition disks?
Authors: Garufi Antonio , Avenhaus Henning , Quanz Sascha P.
Published: January 2014

Dissimilarities in the spatial distribution of small (μm–size) and large (mm–size) dust grains at the cavity edge of transition disks have been recently pointed out and are now under debate. We obtained VLT/NACO near-IR polarimetric observations of SAO 206462 (HD 135344B). The disk around the star shows very complex structures, such as dips and spirals. We also find an inner cavity much smaller than what is inferred from sub-mm images. The interaction between disk and orbiting companion(s) may explain this discrepancy.