bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictors of cognitive impairment in an early stage Parkinson's disease cohort
Authors: Hu Michele T. M. , Szewczyk‐Królikowski Konrad , Tomlinson Paul , Nithi Kannan , Rolinski Michal , Murray Clara , Talbot Kevin , Ebmeier Klaus P. , Mackay Clare E. , Ben‐Shlomo Yoav
Published: January 2014

The impact of Parkinson's disease (PD) dementia is substantial and has major functional and socioeconomic consequences. Early prediction of future cognitive impairment would help target future interventions. The Montreal Cognitive Assessment (MoCA), the Mini‐Mental State Examination (MMSE), and fluency tests were administered to 486 patients with PD within 3.5 years of diagnosis, and the results were compared with those from 141 controls correcting for age, sex, and educational years. Eighteen‐month longitudinal assessments were performed in 155 patients with PD. The proportion of patients classified with normal cognition, mild cognitive impairment (MCI), and dementia varied considerably, depending on the MoCA and MMSE thresholds used. With the MoCA total score at screening threshold, 47.7%, 40.5%, and 11.7% of patients with PD were classified with normal cognition, MCI, and dementia, respectively; by comparison, 78.7% and 21.3% of controls had normal cognition and MCI, respectively. Cognitive impairment was predicted by lower education, increased age, male sex, and quantitative motor and non‐motor (smell, depression, and anxiety) measures. Longitudinal data from 155 patients with PD over 18 months showed significant reductions in MoCA scores, but not in MMSE scores, with 21.3% of patients moving from normal cognition to MCI and 4.5% moving from MCI to dementia, although 13.5% moved from MCI to normal; however, none of the patients with dementia changed their classification. The MoCA may be more sensitive than the MMSE in detecting early baseline and longitudinal cognitive impairment in PD, because it identified 25.8% of those who experienced significant cognitive decline over 18 months. Cognitive decline was associated with worse motor and non‐motor features, suggesting that this reflects a faster progressive phenotype. © 2014 International Parkinson and Movement Disorder Society
Loop‐loop interactions govern multiple steps in indole‐3‐glycerol phosphate synthase catalysis
Authors: Zaccardi Margot J. , O'Rourke Kathleen F. , Yezdimer Eric M. , Loggia Laura J. , Woldt Svenja , Boehr David D.
Published: January 2014

Substrate binding, product release, and likely chemical catalysis in the tryptophan biosynthetic enzyme indole‐3‐glycerol phosphate synthase (IGPS) are dependent on the structural dynamics of the β1α1 active‐site loop. Statistical coupling analysis and molecular dynamic simulations had previously indicated that covarying residues in the β1α1 and β2α2 loops, corresponding to Arg54 and Asn90, respectively, in the Sulfolobus sulfataricus enzyme (ssIGPS), are likely important for coordinating functional motions of these loops. To test this hypothesis, we characterized site mutants at these positions for changes in catalytic function, protein stability and structural dynamics for the thermophilic ssIGPS enzyme. Although there were only modest changes in the overall steady‐state kinetic parameters, solvent viscosity and solvent deuterium kinetic isotope effects indicated that these amino acid substitutions change the identity of the rate‐determining step across multiple temperatures. Surprisingly, the N90A substitution had a dramatic effect on the general acid/base catalysis of the dehydration step, as indicated by the loss of the descending limb in the pH rate profile, which we had previously assigned to Lys53 on the β1α1 loop. These changes in enzyme function are accompanied with a quenching of ps‐ns and µs‐ms timescale motions in the β1α1 loop as measured by nuclear magnetic resonance studies. Altogether, our studies provide structural, dynamic and functional rationales for the coevolution of residues on the β1α1 and β2α2 loops, and highlight the multiple roles that the β1α1 loop plays in IGPS catalysis. Thus, substitution of covarying residues in the active‐site β1α1 and β2α2 loops of indole‐3‐glycerol phosphate synthase results in functional, structural, and dynamic changes, highlighting the multiple roles that the β1α1 loop plays in enzyme catalysis and the importance of regulating the structural dynamics of this loop through noncovalent interactions with nearby structural elements.
Umbilical and fetal middle cerebral artery Doppler reference ranges in a twin population followed longitudinally from 24 to 38 weeks' gestation
Authors: Mulcahy C. , McAuliffe F. M. , Breathnach F. , Geary M. , Daly S. , Higgins J. , Hunter A. , Morrison J. , Burke G. , Higgins S. , Dicker P. , Mahony R. , Tully E. , Malone F.
Published: January 2014

Objective

To construct monochorionic diamniotic (MCDA) and dichorionic diamniotic (DCDA) twin reference ranges for umbilical artery (UA) pulsatility index (PI), UA resistance index (RI), fetal middle cerebral artery (MCA) PI and peak systolic velocity (PSV) and cerebroplacental ratio (CPR) from 24 weeks' to 38 weeks' gestation and compare these with published normal values for singleton pregnancies.

Methods

This prospective multicenter cohort study included 1028 unselected twin pairs recruited over a 2‐year period. Participants with dichorionic twins underwent fortnightly ultrasound surveillance from 24 weeks' gestation, with monochorionic twins being followed every 2 weeks from 16 weeks until delivery. A total of 7536 fetal Doppler examinations in 618 twin pregnancies were included in the analysis, with reference ranges for MCDA and DCDA pregnancies constructed for each of the Doppler indices using multilevel modeling.

Results

UA‐PI and UA‐RI appear to be higher in twins than in singletons, and MCA‐PI and MCA‐PSV appear to be lower. The CPR also appears to be lower in twins than in singletons. Similar MCA indices were observed in MCDA and DCDA twins.

Conclusion

We have established longitudinal reference ranges for UA‐PI and UA‐RI, MCA‐PI and MCA‐PSV and CPR in twin pregnancies, which appear to differ from those in singleton pregnancies. The derived twin‐specific reference ranges may be more appropriate in the surveillance of these high‐risk pregnancies. Applying the singleton CPR cut‐off of ≤ 1.0 may lead to a large number of false‐positive diagnoses of cerebral redistribution in twin fetuses. Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.
Polysiloxane‐Based Block Copolymers as Structure‐Directing Agents in the Synthesis of Hierarchically Organized Silica Monoliths
Authors: Hartmann Sarah , Elsaesser Michael S. , Hüsing Nicola
Published: January 2014

In this work the successful application of commercially available, linear PEO‐PDMS‐PEO block copolymers in the synthesis of hierarchically organized silica monoliths comprising a periodic arrangement of mesopores as well as a well‐defined macroporous morphology is presented. All silica monoliths were synthesized via the sol‐gel approach with an ethylene glycol‐modified silane (EGMS) as precursor. Beyond their use as structure‐directing agents, these siloxane surfactants can also be employed as agents to tailor the surface polarity by controlled thermal decomposition of the hydrophilic PEO blocks resulting in a hydrophobic organosiloxane‐covered surface.
The Largely Unknown Class of Microporous Hybrid Materials: Clays Pillared by Molecules
Authors: Herling Markus M. , Breu Josef
Published: January 2014

The review summarizes recent progress in the field of synthetic clay minerals pillared with organic or metal complex cations (PILCs). We briefly introduce the field of such PILCs and discuss the weaknesses of the state of the art characterization chart of PILCs. When PILCs are made from nanoscopic host materials like natural clay minerals, charge heterogeneity accompanied by interstratification, the turbostratic disorder in the stacking and the influence of the large external surface weaken essential analytical results. Turning to coarse‐grained, well ordered clay minerals synthesized from the melt at temperatures above 1000 K removes all these obstacles and allows to present consistent data underlining the validity of the appealing pillaring concept: Refinement of PILC structures gives information on the pillar‐host interaction and the orientation of pillars in the interlayer space. Two‐dimensional superstructure reflections give direct evidence of the well‐ordered lateral arrangement of pillars. And most importantly, analysis of chemical composition and physisorption isotherms are not corrupted by contributions of large external surfaces and this allows for predicting micropore volume and widths from pillar/host ratios in combination with pillar size/shape. Moreover, recent progress allows fine‐tuning the charge density of the host lattice post‐synthesis. Such deliberate and fine‐graded alteration of the pillar density in turn permits adjusting the pore size in steps as small as 0.1 Å to a given adsorbate and thus will pave the way to maximize adsorption enthalpies and to improve selectivity. This feature is unique to PILCs and is not available to MOFs whose porosity can be adjusted only in steps no smaller than the order of chemical bond lengths. Rational design of microporous hybrid materials with full control over size, shape, and chemical nature of micropores certainly represents the strength and great potential of the pillaring approach.
Translation and Cultural Adaptation of the Brief Michigan Hand Questionnaire to Brazilian Portuguese Language
Authors: Fernandes Carlos Henrique , Neto Jorge Raduan , Meirelles Lia Miyamoto , Pereira Carina Nascimento Mastrocinque , Santos João Baptista Gomes dos , Faloppa Flavio
Published: January 2014

Purpose

The use of patient-reported outcome questionnaires is recommended in orthopedic studies. However, validated tools are necessary to ensure the comparability of results across different studies, centers, and countries. The Brief Michigan Hand Questionnaire (BMHQ) can be used for outcome measures in self-evaluation after carpal tunnel release. This study aimed to translate the BMHQ to Portuguese to permit cross-cultural adaptation to Brazilians patients.

Methods

We translated the Brief Michigan Hand Questionnaire from the original version (English) to Brazilian Portuguese. The translation and cultural adaptation of the content of this tool consisted of six stages, according to the methodology proposed by medical literature: (1) initial translation of the questionnaire by two independent translators; (2) synthesis of translations and reconciliation; (3) back-translation to English of the reconciled version; (4) verification of the cultural equivalence process by an expert committee; (5) pre-testing in a sample of patients to verify understanding of the items; and (6) development of a final version of the BMHQ.

Results

The pre-final version of the tool was applied to 43 patients to verify its understanding. Pre-testing showed that the questions and options were satisfactorily understood. The number of items from the original English version was maintained in the Brazilian Portuguese version of BMHQ.

Discussion

The Brazilian Portuguese version of the BMHQ is easily understood by patients and will be useful to clinicians and researchers.
New pyrenocarpous lichens from NE Argentina
Authors: APTROOT André , FERRARO Lidia Itatí , CÁCERES Marcela Eugenia da Silva
Published: January 2014

Five new species of corticolous pyrenocarpous lichens are described from tropical and subtropical forests in the Chaco and Misiones provinces in NE Argentina:Aspidothelium submuriformewith globose, grey ascomata and ascospores mostly 7-septate with 0–2 oblique longitudinal septa, 25–28×8–10 µm;Pyrenula inspersoleucotrypa, characterized by a thallus without pseudocyphellae, aggregated ascomata, an inspersed hamathecium, and ascospores of 17–20×6·5–8·0 µm with diamond-shaped lumina;Pyrenula punctoleucotrypa, which has a thallus with pseudocyphellae, aggregated ascomata in a conical pseudostroma, with fused ostioles, not inspersed hamathecium, and ascospores of 10–12×4–5 µm with rounded lumina;Strigula muriconidiata, containing immersed pycnidia with hyaline, densely muriform, ellipsoid conidia, 90–103×32–35 µm;Trypethelium globolucidum,forming sessile pseudostromata with black and whitish parts, an inspersed hamathecium, ascospores 13–19-septate, (65–)83–97×11·5–14·5 µm, lumina rounded to lentiform and containing lichexanthone.
Phylogenetic position of the crustose Stereocaulon species
Authors: HÖGNABBA Filip , PINO-BODAS Raquel , NORDIN Anders , MYLLYS Leena , STENROOS Soili
Published: January 2014

Phylogenetic relationships of Stereocaulon with emphasis on the crustose taxa were studied based on nuclear ribosomal ITS1–5.8S–ITS2 and partial beta-tubulin sequences. The placement of four of the six crustose species currently included in the genus has previously been confirmed based on molecular data. It has, however, remained unresolved whether the crustose growth form is a plesiomorphic or apomorphic feature within Stereocaulon, due to contradictory placements of the crustose species in earlier studies. The aim of this study was to clarify the position of the crustose species by including additional data, especially of S. nivale and S. plicatile, which have not been included in previous analyses. The inclusion of S. plicatile in the genus is of particular interest as it is the only species in the genus with submurifrom to muriform ascospores. Altogether 37 specimens representing 31 species of the ingroup, including all the crustose Stereocaulon species, were incorporated in the analyses. Conventional, as well as direct optimization parsimony, maximum likelihood and Bayesian analyses were performed. The results show that the crustose species do not form a monophyletic entity and that the crustose growth form is a plesiomorphic feature within Stereocaulon. The crustose S. nivale and S. plicatile are nested within the genus and their inclusion in Stereocaulon is thereby confirmed. The nested position of S. plicatile indicates that the submuriform to muriform spore type has been gained independently within the genus. Here, S. plicatile is also reported for the first time from Scandinavia.
Rain, dew, and humid air as drivers of morphology, function and spatial distribution in epiphytic lichens
Authors: GAUSLAA Yngvar
Published: January 2014

This review is a first attempt to combine and compare spatial distribution of the three main water sources, rain, dew and humid air, with water-related traits of mainly epiphytic macrolichens in a conceptual and functional model. By comparing climatic and lichenological knowledge, various effects of dewfall, rainfall and humid air on epiphytic lichen morphology and function are analyzed to search for traits and patterns. Although dew, rain and humid air cause lichen hydration and activate photosynthesis, these atmospheric hydration sources influence and shape lichens differently. In order to visualize hydration patterns, dew, rain and humid air are shown as corners in a triangle exhibiting the various combinations of these hydration sources. The sources of hydration vary on temporal scales, and on the spatial scales: regional, landscape, stand and tree. Lichen growth form, photobiont type, water-holding capacity (WHC) and suprasaturation depression show clear patterns within the hydration triangle. For most lichen species, one average pre-dawn dewfall approximately fills their average internal WHC. This suggests that lichens are optimally designed to utilize dew rather than rain, consistent with literature emphasizing dew as a driver for annual C-assimilation in chlorolichens. However, rain is needed to fill their external WHC and to fully hydrate most cyanolichens. Including the sources of hydration and internal lichen variables, such as water-holding capacity, will improve modelling of local and global future scenarios on lichen distribution and biomass production.
Dietary cholesterol, heart disease risk and cognitive dissonance
Authors: McNamara Donald J.
Published: January 2014

In the 1960s, the thesis that dietary cholesterol contributes to blood cholesterol and heart disease risk was a rational conclusion based on the available science at that time. Fifty years later the research evidence no longer supports this hypothesis yet changing the dietary recommendation to limit dietary cholesterol has been a slow and at times contentious process. The preponderance of the clinical and epidemiological data accumulated since the original dietary cholesterol restrictions were formulated indicate that: (1) dietary cholesterol has a small effect on the plasma cholesterol levels with an increase in the cholesterol content of the LDL particle and an increase in HDL cholesterol, with little effect on the LDL:HDL ratio, a significant indicator of heart disease risk, and (2) the lack of a significant relationship between cholesterol intake and heart disease incidence reported from numerous epidemiological surveys. Over the last decade, many countries and health promotion groups have modified their dietary recommendations to reflect the current evidence and to address a now recognised negative consequence of ineffective dietary cholesterol restrictions (such as inadequate choline intake). In contrast, health promotion groups in some countries appear to suffer from cognitive dissonance and continue to promote an outdated and potentially hazardous dietary recommendation based on an invalidated hypothesis. This review evaluates the evidence for and against dietary cholesterol restrictions and the potential consequences of such restrictions.
The contribution of familial internalizing and externalizing liability factors to borderline personality disorder
Authors: Hudson J. I. , Zanarini M. C. , Mitchell K. S. , Choi-Kain L. W. , Gunderson J. G.
Published: January 2014

Background

Individuals with borderline personality disorder (BPD) frequently display co-morbid mental disorders. These disorders include ‘internalizing’ disorders (such as major depressive disorder and anxiety disorders) and ‘externalizing’ disorders (such as substance use disorders and antisocial personality disorder). It is hypothesized that these disorders may arise from latent ‘internalizing’ and ‘externalizing’ liability factors. Factor analytic studies suggest that internalizing and externalizing factors both contribute to BPD, but the extent to which such contributions are familial is unknown.

Method

Participants were 368 probands (132 with BPD; 134 without BPD; and 102 with major depressive disorder) and 885 siblings and parents of probands. Participants were administered the Diagnostic Interview for DSM-IV Personality Disorders, the Revised Diagnostic Interview for Borderlines, and the Structured Clinical Interview for DSM-IV.

Results

On confirmatory factor analysis of within-person associations of disorders, BPD loaded moderately on internalizing (factor loading 0.53,s.e. = 0.10, p < 0.001) and externalizing latent variables (0.48,s.e. = 0.10, p < 0.001). Within-family associations were assessed using structural equation models of familial and non-familial factors for BPD, internalizing disorders, and externalizing disorders. In a Cholesky decomposition model, 84% (s.e. = 17%, p < 0.001) of the association of BPD with internalizing and externalizing factors was accounted for by familial contributions.

Conclusions

Familial internalizing and externalizing liability factors are both associated with, and therefore may mutually contribute to, BPD. These familial contributions account largely for the pattern of co-morbidity between BPD and internalizing and externalizing disorders.
Rhythmic play, compositional intent and communication in rock music
Authors: Hesselink Nathan
Published: January 2014

This paper focuses on the use of rhythmic play in the compositional strategies of rock musicians. Such play is seen as both embodying an attitude on the part of the performer-composer in which music as pure structure tests one's skill and imagination in sonic reality, and as an attempt at a special kind of communication with his or her audience. In this latter capacity the musical work becomes an unspoken or hidden challenge to the listener as a kind of in-group or insider knowledge. Listening thus becomes a window into the creative act, bands and their audiences forming an extended community based on trust, respect and a sense of shared ownership.
Spatial extension of the electromagnetic field from tightly focused ultra-short laser pulses
Authors: Ionel L. , Ursescu D.
Published: January 2014

It is shown that in the focus of ultra-short pulses of duration t, the equivalent relation s = ct, where c is the speed of light and s the spatial extent of the pulse of the collimated pulse, does not hold. While the duration of one pulse is constant and independent of the measurement point, the spatial extension of the ultra-short pulse can be spatially shorter a factor more than 10 compared to the one obtained from the usual relation. The result is explained in correspondence with the extension of the Rayleigh range. Few femtosecond long gamma bursts can thus be generated in Thomson backscattering experiments performed in the lambda cube regime.
A NOTE ON COMPARING DEEP AND AGGREGATE HABIT FORMATION IN AN ESTIMATED NEW KEYNESIAN MODEL
Authors: Givens Gregory E.
Published: January 2014

Habit formation is a fixture of contemporary new Keynesian models. The vast majority assume that agents form habits strictly over consumption of an aggregate good, leaving open the question of whether it might be preferable to have them form habits over differentiated products instead–an arrangement known as deep habits. I answer this question by estimating a model that nests both habit concepts as special cases. Estimates reveal that the data favor a specification in which consumption habits are stronger at the product level than at the aggregate level. A mix of significance tests and simulation results indicate that including deep habits greatly improves model fit, most notably with regard to inflation dynamics.
Bimodal chemical evolution of the Galactic disk and the Barium abundance of Cepheids
Authors: Lépine Jacques R.D. , Andrievky Sergei , Barros Douglas A. , Junqueira Thiago C. , Scarano Sergio
Published: January 2014

In order to understand the Barium abundance distribution in the Galactic disk based on Cepheids, one must first be aware of important effects of the corotation resonance, situated a little beyond the solar orbit. The thin disk of the Galaxy is divided in two regions that are separated by a barrier situated at that radius. Since the gas cannot get across that barrier, the chemical evolution is independent on the two sides of it. The barrier is caused by the opposite directions of flows of gas, on the two sides, in addition to a Cassini-like ring void of HI (caused itself by the flows). A step in the metallicity gradient developed at corotation, due to the difference in the average star formation rate on the two sides, and to this lack of communication between them. In connection with this, a proof that the spiral arms of our Galaxy are long-lived (a few billion years) is the existence of this step. When one studies the abundance gradients by means of stars which span a range of ages, like the Cepheids, one has to take into account that stars, contrary to the gas, have the possibility of crossing the corotation barrier. A few stars born on the high metallicity side are seen on the low metallicity one, and vice-versa. In the present work we re-discuss the data on Barium abundance in Cepheids as a function of Galactic radius, taking into account the scenario described above. The [Ba/H] ratio, plotted as a function of Galactic radius, apparently presents a distribution with two branches in the external region (beyond corotation). One can re-interpret the data and attribute the upper branch to the stars that were born on the high metallicity side. The lower branch, analyzed separately, indicates that the stars born beyond corotation have a rising Barium metallicity as a function of Galactic radius.
Dynamical models and Galaxy surveys
Authors: Binney James , Sanders Jason L.
Published: January 2014

Equilibrium dynamical models are essential tools for extracting science from surveys of our Galaxy. We show how models can be tested with data from a survey before the survey's selection function has been determined. We illustrate the application of this method by presenting some results for the RAVE survey. We extend our published analytic distribution functions to include chemistry and fit the chosen functional form to a combination of the Geneva–Copenhagen survey (GCS) and a sample of G-dwarfs observed atz~ 1.75 kpc by the SEGUE survey. By including solid dynamics we are able to predict the contribution that the thick disc/halo stars surveyed by SEGUE should make to the GCS survey. We show that the measured [Fe/H] distribution from the GCS includes many fewer stars at [Fe/H] < −0.6 than are predicted. The problem is more likely to lie in discordant abundance scales than with incorrect dynamics.
The chemodynamical evolution of the Milky Way disc – A new modeling approach
Authors: Minchev Ivan , Chiappini Cristina , Martig Marie
Published: January 2014

Despite the recent advancements in the field of galaxy formation and evolution, fully self-consistent simulations are still unable to make the detailed predictions necessary for the planned and ongoing large spectroscopic and photometric surveys of the Milky Way disc. These difficulties arise from the very uncertain nature of sub-grid physical energy feedback within models, affecting both star formation rates and chemical enrichment. To avoid these problems, we have introduced a new approach which consists of fusing disc chemical evolution models with compatible numerical simulations. We demonstrate the power of this method by showing that a range of observational results can be explained by our new model. We show that due to radial migration from mergers at high redshift and the central bar at later times, a sizable fraction of old metal-poor, high-[α/Fe] stars can reach the solar vicinity. This naturally accounts for a number of recent observations related to both the thin and thick discs, despite the fact that we use thin-disc chemistry only. Within the framework of our model, the MW thick disc has emerged naturally from (i) stars born with high velocity dispersions at high redshift, (ii) stars migrating from the inner disc very early on due to strong merger activity, and (iii) further radial migration driven by the bar and spirals at later times. A significant fraction of old stars with thick-disc characteristics could have been born near the solar radius.
The Milky Way and the current status of galaxy formation models
Authors: Tissera Patricia B.
Published: January 2014

I summarizes the main characteristics of a cosmological hydro-dynamical model which includes chemical evolution. In the last decade, galaxy formation models have made important progress which contribute to understand observations although there are still many open questions to be answered. Current chemo-dynamical cosmological simulations are able to reproduce global trends. They provide a suitable route to underpin physical events responsible of determining observed chemical patterns.
Mapping the three-dimensional multi-band extinction and diffuse interstellar bands in the Milky Way with LAMOST
Authors: Yuan H.-B. , Liu X.-W. , Xiang M.-S , Huo Z.-Y. , Zhang H.-H. , Huang Y. , Zhang H.-W.
Published: January 2014

With modern large scale spectroscopic surveys, such as the SDSS and LSS-GAC, Galactic astronomy has entered the era of millions of stellar spectra. Taking advantage of the huge spectroscopic database, we propose to use a “standard pair" technique to a) Estimate multi-band extinction towards sightlines of millions of stars; b) Detect and measure the diffuse interstellar bands in hundreds of thousands SDSS and LAMOST low-resolution spectra; c) Search for extremely faint emission line nebulae in the Galaxy; and d) Perform photometric calibration for wide field imaging surveys. In this contribution, we present some results of applying this technique to the SDSS data, and report preliminary results from the LAMOST data.
Gaia and variable stars
Authors: Eyer Laurent , Holl Berry , Mowlavi Nami
Published: January 2014

The study of variable phenomena (periodic, irregular or transient) provides a unique way to acquire knowledge about objects in our Universe. Currently, we are going through a rapid expansion of time-domain astrophysics. One reason for this expansion is the technological developments materialised in small to medium size observational projects such as HAT, OGLE, Catalina, PTF and upcoming very large projects such as Gaia or LSST.

In this article, we are focusing on the ESA cornerstone mission Gaia. This spacecraft will provide astrometric, photometric and spectroscopic measurements for one billion stars. Among the existing and planned multi-epoch projects Gaia is unique because it will provide exquisite astrometric measurements for all objects it observes. We provide a brief overview of the literature concerning this mission and its expected contribution to variability studies.
Non-LTE Abundances of Sodium in the Atmospheres of Red Giants of the Thick and Thin Galactic Disks
Authors: Alexeeva Sofya , Pakhomov Yury , Mashonkina Lyudmila
Published: January 2014

We determined NLTE abundances of Na in the atmospheres of 80 red giants including the 33 stars of the thin disk, 35 stars of the thick disk and 12 stars of Hercules stream.
Nearby kinematic wiggles from LEGUE
Authors: Carlin J. L. , Newberg H. J. , Deng L. , Delaunay J. , Gole D. , Grabowski K. , Liu C. , Xu Y. , Yang F. , Zhang H.
Published: January 2014

In its first two observing seasons, the LEGUE (LAMOST Experiment for Galactic Understanding and Exploration; Deng et al., Zhao et al. 2012) survey has obtained ~1.7 million science-quality spectra. We apply corrections to the PPMXL proper motions (PMs; Roeser et al. 2010) as a function of position, as determined from the measured PMs of extragalactic objects discovered in LAMOST spectra (see Fig. 1, left and center panels). LAMOST radial velocities and corrected PMs are used to derive 3D space velocities for ~480,000 F-stars (assuming MV=4 to derive distances). The right panel of Fig. 1 shows the radial component of Galactic cylindrical velocities (VR) for stars between 7.8<RGC<9.8 kpc (with R⊙,GC=7.8 kpc) as a function of height (Z) and angle (θ) from the Galactic X-axis. Each dot represents the average position of stars in a 200x200 pc box, color-coded by the mean VR of those stars. Assuming circularrotation, VR should be zero. This is true on average for θ>0° (3rd Galactic quadrant), but not for θ<0°. The velocities are also asymmetric across the Galactic plane for θ<0° (2nd quadrant), with most positions 〈 VR 〉> 0 above the disk (radially outward), and 〈 VR 〉 < 0 below the disk. Similar structure to this apparent “shearing” motion has been seen in RAVE (e.g., Williams et al. 2013; Siebert et al. 2012), and SDSS (Widrow et al. 2012).
Estimation of Galactic model parameters in high latitudes with the SDSS and SCUSS
Authors: Du Cuihua , Jia Yunpeng , Peng Xiyan
Published: January 2014

Based on the South Galactic Cap U-band Sky Survey (SCUSS) and SDSS observation, we adopted the star-count method to analyze the stellar distribution in different directions of the Galaxy. We find that these model parameters may be variable with observed direction, which cannot simply be attributed to statistical errors.
The global dark halo structure of the Andromeda galaxy
Authors: Hayashi Kohei , Chiba Masashi
Published: January 2014

We set new limits on the global shape of the dark halo in the Andromeda galaxy based on axisymmetric mass models constructed by Hayashi & Chiba (2012). This is motivated by the fact that CDM models predict non-spherical virialized dark halos, which reflect the process of mass assembly in the galactic scale. Based on the application of our models to latest kinematical data of globular clusters and dwarf spheroidal galaxies in the Andromeda halo, we find that the most plausible cases for Andromeda yield not a spherical but a prolate shape for its dark halo. We also find that the prolate dark halo is consistent with theoretical predictions in which the satellites are distributed anisotropically and preferentially located along major axes of their galactic host halos. It is a reflection of the intimate connection between galactic dark matter halos and the cosmic web.
The Chemical Evolution of Heavy Elements in Globular Clusters
Authors: Shingles Luke J. , Karakas Amanda I. , Hirschi Raphael
Published: January 2014

We present preliminary results from a chemical evolution model that tracks the composition of heavy elements beyond iron in a globular cluster. The heavy elements can be used as tracers of the nucleosynthetic events that defined the formation and evolution of star clusters in the early Universe. In particular, the chemical evolution model focuses on the hypothesis that rapidly-rotating massive stars produced the heavy elements via the slow neutron-capture process and seeded the proto-cluster while the stars we see today were still forming.

We compare our model with heavy element abundances in M4 and M5, and M22. Our results are strongly dependent on the highly uncertain rate of the 17O(α,γ)21Ne reaction, which determines the strength of 16O as a neutron poison. We find that the [Pb/Ba] ratio is too low to match the empirical value, which might suggest that a contribution from AGB stars is required.
The Large Binocular Telescope Interferometer & Adaptive Optics System: On-sky Performance and Results
Authors: Bailey Vanessa , Hinz Philip , Vaitheeswaran Vidhya , Skemer Andrew , Defrère Denis , Rodigas Timothy , Esposito Simone , Pinna Enrico , Puglisi Alfio
Published: January 2014

Increasing spatial resolution and contrast capabilities will make possible new direct detections of exoplanets, exozodis, and circumstellar disks. The Large Binocular Telescope Interferometer (LBTI) has been engineered to sit at the combined focus of the Large Binocular Telescope's two 8.4m apertures. Both apertures are equipped with 672-actuator deformable secondary mirrors, the first of the next generation of “extreme” adaptive optics (AO) systems. We present an overview of the LBTI AO instrument suite and detail current on-sky performance.
Archival Legacy Investigation of Circumstellar Environments using KLIP algorithm on HST NICMOS coronagraphic data
Authors: Choquet Elodie , Hagan J. Brendan , Pueyo Laurent , Perrin Marshall D. , Hines Dean C. , Chen Christine , Schneider Glenn , Debes John , Golimowski David , Reid Neill , Mittal Tushar , Moerchen Margaret , N'Diaye Mamadou , Rajan Abhijith , Lonsdale Sean , Soummer Remi
Published: January 2014

The Archival Legacy Investigation of Circumstellar Environments (ALICE) project (AR-12652) is currently conducting a comprehensive and consistent reprocessing of HST-NICMOS coronagraphic survey data to search for point sources and disks using advanced PSF subtraction. The KLIP algorithm (Karhunen-Loève Image Projection) was developed for this project, and has proven very effective at processing the hundreds of selected archival images. This project has already been very successful with numerous detections of previously unseen point sources and several resolved debris disks that we are currently following up by multiple avenues. We give an overview of the project including preliminary scientific results with companion candidates and improved images of known disks
Performance tests on the SPHERE-IFS
Authors: Mesa Dino , Gratton Raffaele , Claudi Riccardo U. , Desidera Silvano , Giro Enrico , Zurlo Alice , Costille Anne , Vigan Arthur , Moutou Claire , Beuzit Jean-Luc , Dohlen Kjetil , Feldt Markus , Mouillet David , Sauvage Jean-Francois , Kasper Markus , Antichi Jacopo
Published: January 2014

Until now, just a few extrasolar planets (30 out of 860) have been found through the direct imaging method. This number should greatly improve when the next generation of High Contrast Instruments like Gemini Planet Imager (GPI) at Gemini South Telescope or SPHERE at VLT will became operative at the end of this year. In particular, the Integral Field Spectrograph (IFS), one of the SPHERE subsystems, should allow a first characterization of the spectral type of the found extrasolar planets. Here we present the results of the last performance tests that we have done on the IFS instrument at the Institut de Planetologie et d'Astrophysique de Grenoble (IPAG) in condition as similar as possible to the ones that we will find at the telescope. We have found that we should be able to reach contrast down to 5 × 10−7 and make astrometry at sub-mas level with the instrument in the actual conditions. A number of critical issues have been identified. The resolution of these problems could allow to further improve the performance of the instrument.
Giant planets around AF and M stars
Authors: Rameau Julien , Chauvin Gaël , Lagrange Anne-Marie , Delorme Philippe , Lannier Justine
Published: January 2014

We present the results of two three-year surveys of young and nearby stars to search for wide orbit giant planets. On the one hand, we focus on early-type and massive, namely β Pictoris analogs. On the other hand, we observe late type and very low mass stars, i.e., M dwarfs. We report individual detections of new planetary mass objects. According to our deep detection performances, we derive the observed frequency of giant planets between these two classes of parent stars. We find frequency between 6 to 12% but we are not able to assess a/no correlation with the host-mass.
The inner disks of EXor-type eruptive stars
Authors: Sipos Nikoletta , Kóspál Ágnes
Published: January 2014

EX Lupi-type young stars (EXors) show sporadic brightenings of several magnitudes, caused by the episodic increase in the accretion rate of the circumstellar matter onto the young star. As the inner disk plays a crucial role during the onset of the outburst, we examined the quiescent properties of the circumstellar environment of EXors, focusing on the inner regions. We found that in case of three EXors (VY Tau, V1143 Ori and EX Lup) the spectral energy distributions show no or weak excess above the stellar photosphere at NIR-MIR wavelengths, indicative of inner disk clearing. A detailed radiative transfer modeling of the sources revealed that the inner regions of these disks had to go through significant evolution, either the inner radius of the dusty disk is beyond the sublimation radius and/or the inner disks are flattened.
Substructure and Signs of Planet Formation in the Disk of HD 169142
Authors: Osorio M. , Anglada G. , Carrasco-González C. , Torrelles J. M. , D'Alessio P. , Rodríguez L. F. , Calvet N. , Gómez J. F. , Mayen-Gijon J. M. , Dent W. R. F.
Published: January 2014

We carried out 7 mm VLA observations at very high angular resolution that reveal substructure and evidence of planet formation in the disk of HD 169142. Our observations, along with near-infrared polarimetric imaging, show that this disk has a ring of enhanced, asymmetric emission at a radius of ~25 AU from the central star. This ring, whose inner region appears devoid of emission, is surrounded by an annular gap in surface density in the ~30-70 AU range of radii. Several mechanisms have been invoked in the literature to explain this kind of gaps and cavities. Among them, one of the most interesting is the possibility that one or more planets in formation are creating these cavities. Since our 7 mm observations show a compact source lying in the 30-70 AU gap, we speculate that this compact source could be tracing dust emission associated with a possible protoplanet. We model the broad-band spectral energy distribution of the disk and we infer its physical structure. From this modeling we infer the presence of a small (r ~ 0.7 AU) disk inside the central cavity, suggesting that the HD 169142 disk is in the pre-transitional disk phase.
On the evolution of the Snow Line in Protoplanetary Discs
Authors: Martin Rebecca G. , Livio Mario
Published: January 2014

We examine the evolution of the snow line in a protoplanetary disc. If the magneto-rotational instability (MRI) drives turbulence throughout the disc, there is a unique snow line outside of which the disc is icy. The snow line moves closer to the star as the infall accretion rate drops. Because the snow line moves inside the radius of the Earth's orbit, the formation of our water-devoid planet is difficult with this model. However, protoplanetary discs are not likely to be sufficiently ionised to be fully turbulent. A dead zone at the mid-plane slows the flow of material through the disc and a global steady state cannot be achieved. We model the evolution of the snow line also in a disc with a dead zone. As the mass is accumulating, the outer parts of the dead zone become self gravitating, heat the massive disc and thus the outer snow line does not come inside the radius of the Earth's orbit. With this model there is sufficient time and mass in the disc for the Earth to form from water-devoid planetesimals at a radius of 1AU. Furthermore, the additional inner icy region within the dead zone predicted by this model may allow for the formation of giant planets close to their host star without the need for much migration.
Inviscid and viscous flow past embedded planets: implications for planet formation
Authors: Ormel Chris W. , Shi Ji-Ming
Published: January 2014

We have investigated the flow pattern that arises past (proto)planets embedded in the nebula disk during its formation. We consider the regime where the planet mass is large enough to gravitationally perturb the gas (≳0.01 Earth masses), but not too large to open a gap or accrete unlimited amounts of gas from the disk. We consider both inviscid and viscid flows and aim to understand the flow pattern on the scales of the Bondi radius. Having described the flow pattern of the gas, we integrate trajectories of small, solid particles. In agreement with previous findings, we show that the ensuing accretion rates can be high—although, due to radial drift motions, pebble accretion is not necessarily an efficient mechanism.
HST/STIS imaging of Fomalhaut: New main belt structure and confirmation of Fomalhaut b's eccentric orbit
Authors: Kalas P. , Graham J. R. , Fitzgerald M. P. , Clampin M.
Published: January 2014

High contrast imaging observations with the Hubble Space Telescope show that the nearby star Fomalhaut is surrounded by a dusty debris belt and a candidate planet, Fomalhaut b, located just inside the edge of the belt. Fomalhaut b has unexpected characteristics, such as a relatively blue spectrum, leading to the hypothesis that the detected object is a low-mass planet hosting a giant planetary dust ring or cloud seen in reflected light. Here we present new HST/STIS observations made in 2010 and 2012 that authenticate the existence of Fomalhaut b. Our MCMC analysis of four epochs of astrometry spread over eight years indicate that the orbit has a~170 AU and e~0.85. Fomalhaut b's orbit is apsidally aligned with the main belt, and periapse is located approximately ~30 AU south of the star. We also show the existence of a ~50 AU wide azimuthal dust depletion in the dust belt. These new findings provide a revised picture of Fomalhaut as a dynamically complex system, where the orbit of Fomalhaut b and the belt structure signify the presence of additional massive planets orbiting the star.
Angular momentum evolution during star and planetary system formation
Authors: Davies Claire L. , Greaves Jane S.
Published: January 2014

We focused on analysing the role played by protoplanetary disks in the evolution of angular momentum during star formation. If all the angular momentum contained within collapsing pre-stellar cores was conserved during their formation, proto-stars would reach rotation rates exceeding their break-up velocities before they reached the main sequence (Bodenheimer 1995). In order to avoid this occuring, methods by which proto-stars can lose angular momentum must exist. Angular momentum can be transferred from star to disk via stellar magnetic field lines through a process called magnetic braking (Camenzind 1990; Königl 1991). Alternatively, the stellar angular momentum can be lost from the star-disk system entirely via stellar- or disk-winds (e.g. Pelletier & Pudritz 1992; Matt & Pudritz 2005).

The proportion of lost stellar angular momentum retained within the protoplanetary disk is important to studies of planetary system formation. If the bulk motion within the disk remains Keplerian, any increase of angular momentum in the disk causes an outward migration of disk material and an expansion of the disk. Therefore, an increase in disk angular momentum may cause a reduction in the disk surface density, often used to indicate the disk's ability to form planets.

We made use of multi-wavelength data available in the literature to directly calculate the stellar and disk angular momenta for two nearby regions of star formation. Namely, these were the densely populated and highly irradiated Orion Nebula Cluster (ONC) and the comparitively sparse Taurus-Auriga region. Due to the limited size of the ONC dataset, we produced an average surface density profile for the region. We modelled the stars as solid body rotators due to their fully convective nature (Krishnamurthi et al. 1997) and assumed the disks are flat and undergo Keplerian rotation about the same rotation axis as the star.

We observed the older disks within each of the two star forming regions to be preferentially larger and less massive, consistent with viscous accretion theories and disk dispersal. However, when drawing comparisons between the two regions, the ONC sample appeared to have less massive disks than the Taurus-Auriga sample, even though the population of Taurus-Auriga is older. This may suggest an influence of the birth cloud environment on protoplanetary disk evolution.

Finally, the older stars within the ONC were observed to harbour disks that contained more angular momentum than their younger counterparts whereas, in the Taurus-Auriga sample, the amount of angular momentum contained in the older and younger samples was consistent. We suggest that the missing disk angular momentum in the older Taurus-Auriga disks may be contained within yet-undetected planets.
Variability of CHXR 20: accretion, extinction, spots or a companion?
Authors: Kopytova Taisiya G. , Joergens Viki , Sicilia-Aguilar Aurora , Rodríguez-Ledesma Maria V. , Mundt Reinhard
Published: January 2014

We study the photometric variability of a pre-main sequence star (K6, 0.9M⊙) CHXR 20. We test several scenarios for the variability including variable accretion, variable extinction, cool and hot spots on the stellar surface and the presence of a potential companion.
Gravitational instability of planetary gaps and its effect on orbital migration
Authors: Lin Min-Kai , Cloutier Ryan
Published: January 2014

Gap formation by giant planets in self-gravitating disks may lead to a gravitational edge instability (GEI). We demonstrate this GEI with global 3D and 2D self-gravitating disk-planet simulations using the ZEUS, PLUTO and FARGO hydrodynamic codes. High resolution 2D simulations show that an unstable outer gap edge can lead to outward migration. Our results have important implications for theories of giant planet formation in massive disks.
Astrometry in the Service of Planet Formation Studies: Disk Lifetimes in Nearby Star Forming Regions and a Planet Candidate around a Mature Brown Dwarf
Authors: Weinberger Alycia J. , Boss Alan P. , Anglada-Escudé Guillem
Published: January 2014

We present preliminary astrometric results aimed at understanding the lifetime of circumstellar disks and potential for planet formation. We have obtained parallaxes to stars in the TW Hydrae, Upper Scorpius, and Chamaeleon I stellar associations. These enable new estimates for the ages of the stars. We are also performing the Carnegie Astrometric Planet Search of nearby low mass stars for gas giant planets on wide orbits. We have our first candidate around a mature brown dwarf.