bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of the Spanish Version of the LASSI-L for Diagnosing Mild Cognitive Impairment and Alzheimer’s Disease
Authors: Matías-Guiu Jordi A. , Curiel Rosie E. , Rognoni Teresa , Valles-Salgado María , Fernández-Matarrubia Marta , Hariramani Roshan , Fernández-Castro Alejandro , Moreno-Ramos Teresa , Loewenstein David A. , Matías-Guiu Jorge 
Published: December 2016

Background: The Loewenstein-Acevedo Scale for Semantic Interference and Learning (LASSI-L) is a novel cognitive test that measures recovery from proactive semantic interference, which may be an early cognitive marker of Alzheimer’s disease (AD). Objective: To generate normative data for a Spaniard population and to validate the LASSI-L for the diagnosis of amnestic mild cognitive impairment (aMCI) and mild AD. Methods: We performed a cross-sectional study in which 97 healthy participants, 34 with aMCI, and 33 with mild AD were studied with LASSI-L and a comprehensive neuropsychological protocol. The overlapping strategy analysis was used to maximize the sample size and to provide age- and education-adjusted normative data using a logistic regression analysis. Results: Internal consistency was 0.932. Convergent validity with the Free and Cued Selective Reminding Test was moderate. LASSI-L raw scores were correlated with age and years of education, but not gender. The area under the curve for discriminating between healthy controls and aMCI was 0.909, and between healthy controls and mild AD was 0.986. LASSI-L sub-scores representing maximum storage capacity, recovery from proactive interference, and delayed recall yielded the highest diagnostic accuracy. Conclusions: The LASSI-L is a reliable and valid test for the diagnosis of aMCI and mild AD. The age and education influences on the performance of the test and normative data are provided. LASSI-L merits further studies to evaluate its ability to detect preclinical AD and predict progression to aMCI and early dementia.
FAST SAUSAGE MODES IN MAGNETIC TUBES WITH CONTINUOUS TRANSVERSE PROFILES: EFFECTS OF A FINITE PLASMA BETA
Authors: Chen Shao-Xia , Li Bo , Xiong Ming , Yu Hui , Guo Ming-Zhe 
Published: December 2016

ABSTRACT
While standing fast sausage modes in flare loops are often invoked to interpret quasi-periodic pulsations (QPPs) in solar flares, it is unclear as to how they are influenced by the combined effects of a continuous transverse structuring and a finite internal plasma beta (

). We derive a generic dispersion relation governing linear sausage waves in straight magnetic tubes for which plasma pressure is not negligible, and the density and temperature inhomogeneities of essentially arbitrary form take place in a layer of arbitrary width. Focusing on fast modes, we find that

only weakly influences

, the critical longitudinal wavenumber separating the leaky from trapped modes. Likewise, for both trapped and leaky modes, the periods P in units of the transverse fast time depend only weakly on

, which is compatible with the fact that the effective wave vectors of fast sausage modes are largely perpendicular to the background magnetic field. However, a weak

dependence of the damping times τ is seen only when the length-to-radius ratio L/R is ∼50% larger than some critical value

, which itself rather sensitively depends on the density contrast, profile steepness, as well as on how the transverse structuring is described. In the context of QPPs, we conclude that the much simpler zero-beta theory can be employed for trapped modes, as long as one sees the deduced internal Alfvén speed as actually being the fast speed. In contrast, effects due to a finite beta in flare loops should be considered when leaky modes are exploited.
THE MERGING GALAXY CLUSTER A520—A BROKEN-UP COOL CORE, A DARK SUBCLUSTER, AND AN X-RAY CHANNEL
Authors: H. S. Wang Qian , Markevitch Maxim , Giacintucci Simona 
Published: December 2016

ABSTRACT
We present results from a deep Chandra X-ray observation of a merging galaxy cluster A520. A high-resolution gas temperature map reveals a long trail of dense, cool clumps—apparently the fragments of a cool core that has been stripped from the infalling subcluster by ram pressure. The clumps should still be connected by the stretched magnetic field lines. The observed temperature variations imply that thermal conductivity is suppressed by a factor

across the presumed direction of the magnetic field (as found in other clusters), and is also suppressed along the field lines by a factor of several. Two massive clumps in the periphery of A520, visible in the weak-lensing mass map and the X-ray image, have apparently been completely stripped of gas during the merger, but then re-accreted the surrounding high-entropy gas upon exit from the cluster. The mass clump that hosted the stripped cool core is also reaccreting hotter gas. An X-ray hydrostatic mass estimate for the clump that has the simplest geometry agrees with the lensing mass. Its current gas mass to total mass ratio is very low, 1.5%–3%, which makes it a “dark subcluster.” We also found a curious low X-ray brightness channel (likely a low-density sheet in projection) going across the cluster along the direction of an apparent secondary merger. The channel may be caused by plasma depletion in a region of an amplified magnetic field (with plasma

). The shock in A520 will be studied in a separate paper.
THE SPIRAL WAVE INSTABILITY INDUCED BY A GIANT PLANET. I. PARTICLE STIRRING IN THE INNER REGIONS OF PROTOPLANETARY DISKS
Authors: Bae Jaehan , Nelson Richard P. , Hartmann Lee 
Published: December 2016

ABSTRACT
We have recently shown that spiral density waves propagating in accretion disks can undergo a parametric instability by resonantly coupling with and transferring energy into pairs of inertial waves (or inertial-gravity waves when buoyancy is important). In this paper, we perform inviscid three-dimensional global hydrodynamic simulations to examine the growth and consequence of this instability operating on the spiral waves driven by a Jupiter-mass planet in a protoplanetary disk. We find that the spiral waves are destabilized via the spiral wave instability (SWI), generating hydrodynamic turbulence and sustained radially alternating vertical flows that appear to be associated with long wavelength inertial modes. In the interval

, where R
p denotes the semimajor axis of the planetary orbit (assumed to be 5 au), the estimated vertical diffusion rate associated with the turbulence is characterized by

. For the disk model considered here, the diffusion rate is such that particles with sizes up to several centimeters are vertically mixed within the first pressure scale height. This suggests that the instability of spiral waves launched by a giant planet can significantly disperse solid particles and trace chemical species from the midplane. In planet formation models where the continuous local production of chondrules/pebbles occurs over Myr timescales to provide a feedstock for pebble accretion onto these bodies, this stirring of solid particles may add a time constraint: planetary embryos and large asteroids have to form before a gas giant forms in the outer disk, otherwise the SWI will significantly decrease the chondrule/pebble accretion efficiency.
A SPECTROSCOPIC SEARCH FOR CHEMICALLY STRATIFIED WHITE DWARFS IN THE SLOAN DIGITAL SKY SURVEY
Authors: Manseau P. M. , Bergeron P. , Green E. M. 
Published: December 2016

ABSTRACT
We present a detailed search and analysis of chemically stratified hybrid (traces of helium and hydrogen) white dwarfs in the Sloan Digital Sky Survey (SDSS). Only one stratified white dwarf, PG 1305–017, was known prior to this analysis. The main objective is to confirm the existence of several new stratified objects. We first describe our new generation of stratified model atmospheres, where a thin hydrogen layer floats in diffusive equilibrium on top of a more massive helium layer. We then present the results of our search for hot (

T

eff

> 30,000 K) white dwarfs with a hybrid spectral type among the ∼38,000 white dwarf spectra listed in the SDSS. A total of 51 spectra were retained in our final sample, which we analyze using spectroscopic fits to both chemically homogeneous and stratified model atmospheres. We identify 14 new stratified white dwarfs in the SDSS sample. From these results, we draw several conclusions regarding the physical processes that might explain the presence of helium in the atmospheres of all the stars in our sample.
THE POSSIBLE DETECTION OF A BINARY COMPANION TO A TYPE IBN SUPERNOVA PROGENITOR
Authors: Maund J. R. , Pastorello A. , Mattila S. , Itagaki K. , Boles T. 
Published: December 2016

ABSTRACT
We present late-time observations of the site of the Type Ibn supernova (SN) 2006jc, acquired with the Hubble Space Telescope Advanced Camera for Surveys. A faint blue source is recovered at the SN position, with brightness

,

and

mag, although there is no detection in a contemporaneous narrow-band

image. The spectral energy distribution of the late-time source is well-fit by a stellar-like spectrum (

and

), subject to only a small degree of reddening—consistent with that estimated for SN 2006jc itself at early-times. The lack of further outbursts after the explosion of SN 2006jc suggests that the precursor outburst originated from the progenitor. The possibility of the source being a compact host cluster is ruled out on the basis of the source’s faintness; however, the possibility that the late-time source may be an unresolved light echo originating in a shell or sphere of pre-SN dust (within a radius

) is also discussed. Irrespective of the nature of the late-time source, these observations rule out a luminous blue variable as a companion to the progenitor of SN 2006jc.
NUMERICAL AND ANALYTICAL SOLUTIONS OF NEUTRINO-DOMINATED ACCRETION FLOWS WITH A NON-ZERO TORQUE BOUNDARY CONDITION AND ITS APPLICATIONS IN GAMMA-RAY BURSTS
Authors: Xie Wei , Lei Wei-Hua , Wang Ding-Xiong 
Published: December 2016

ABSTRACT
A stellar-mass black hole (BH) surrounded by a neutrino-dominated accretion flow (NDAF) has been discussed in a number of works as the central engine of gamma-ray bursts (GRBs). It is widely believed that NDAF cannot liberate enough energy for bright GRBs. However, these works have been based on the assumption of a “no torque” boundary condition, which is invalid when the disk is magnetized. In this paper, we present both numerical and analytical solutions for NDAFs with non-zero boundary stresses and reexamine their properties. We find that an NDAF with such a boundary torque can be powerful enough to account for those bright short GRBs, energetic long GRBs, and ultra-long GRBs. The disk becomes viscously unstable, which makes it possible to interpret the variability of GRB prompt emission and the steep decay phase in the early X-ray afterglow. Finally, we study the gravitational waves radiated from a processing BH-NDAF. We find that the effects of the boundary torque on the strength of the gravitational waves can be ignored.
DAMPING OF ALFVÉN WAVES BY TURBULENCE AND ITS CONSEQUENCES: FROM COSMIC-RAY STREAMING TO LAUNCHING WINDS
Authors: Lazarian A. 
Published: December 2016

ABSTRACT
This paper considers turbulent damping of Alfvén waves in magnetized plasmas. We identify two cases of damping, one related to damping of cosmic-ray streaming instability, the other related to damping of Alfvén waves emitted by a macroscopic wave source, e.g., a stellar atmosphere. The physical difference between the two cases is that in the former case the generated waves are emitted with respect to the local direction of the magnetic field, and in the latter, waves are emitted with respect to the mean field. The scaling of damping is different in the two cases. We explore effects of turbulence in the regimes from sub-Alfvénic to super-Alfvénic to obtain analytical expressions for the damping rates and define the ranges of applicability of these expressions. In describing the damping of the streaming instability, we find that for sub-Alfvénic turbulence, the range of cosmic-ray energies influenced by weak turbulence is unproportionally large compared to the range of scales where weak turbulence is present. On the contrary, the range of cosmic-ray energies affected by strong Alfvénic turbulence is rather limited. A number of astrophysical applications of the process ranging from launching of stellar and galactic winds to propagation of cosmic rays in galaxies and clusters of galaxies is considered. In particular, we discuss how to reconcile the process of turbulent damping with the observed isotropy of the Milky Way cosmic rays.
THE MEASUREMENT, TREATMENT, AND IMPACT OF SPECTRAL COVARIANCE AND BAYESIAN PRIORS IN INTEGRAL-FIELD SPECTROSCOPY OF EXOPLANETS
Authors: Greco Johnny P. , Brandt Timothy D. 
Published: December 2016

ABSTRACT
The recovery of an exoplanet’s atmospheric parameters from its spectrum requires accurate knowledge of the spectral errors and covariances. Unfortunately, the complex image processing used in high-contrast integral-field spectrograph (IFS) observations generally produces spectral covariances that are poorly understood and often ignored. In this work, we show how to measure the spectral errors and covariances and include them self-consistently in parameter retrievals. By combining model exoplanet spectra with a realistic noise model generated from the Gemini Planet Imager (GPI) early science data, we show that ignoring spectral covariance in high-contrast IFS data can both bias inferred parameters and lead to unreliable confidence regions on those parameters. This problem is made worse by the common practice of scaling the χ
2 per degree of freedom to unity; the input parameters then fall outside the 95% confidence regions in as many as ∼80% of noise realizations. The biases we observe can approach the typical levels of precision achieved in high-contrast spectroscopy. Accounting for realistic priors in fully Bayesian retrievals can also have a significant impact on the inferred parameters. Plausible priors on effective temperature and surface gravity can vary by an order of magnitude across the confidence regions appropriate for objects with weak age constraints; priors for objects with good age constraints are dominated by modeling uncertainties. Our methods are directly applicable to existing high-contrast IFSs including GPI and SPHERE, as well as upcoming instruments like CHARIS and, ultimately, WFIRST-AFTA.
MAPPING THE MOST MASSIVE OVERDENSITY THROUGH HYDROGEN (MAMMOTH). I. METHODOLOGY
Authors: Cai Zheng , Fan Xiaohui , Peirani Sebastien , Bian Fuyan , Frye Brenda , McGreer Ian , Prochaska J. Xavier , Lau Marie Wingyee , Tejos Nicolas , Ho Shirley , Schneider Donald P. 
Published: December 2016

ABSTRACT
Modern cosmology predicts that a galaxy overdensity (e.g., protocluster) will be associated with a large intergalactic medium gas reservoir, which can be traced by Lyα forest absorption. We have undertaken a systematic study of the relation between Coherently Strong intergalactic Lyα Absorption systems (CoSLAs), which have the highest optical depth (τ) in the τ distribution, and mass overdensities on the scales of ∼10–20 h
−1 comoving Mpc. On such large scales, our cosmological simulations show a strong correlation between the effective optical depth (τ
eff) of the CoSLAs and the three-dimensional mass overdensity. In spectra with moderate signal-to-noise ratio, however, the profiles of CoSLAs can be confused with individual high column density absorbers. For z > 2.6, where the corresponding Lyβ is redshifted to the optical, we have developed a selection technique to distinguish between these two alternatives. We have applied this technique to ∼6000 sight lines provided by Sloan Digital Sky Survey III quasar survey at z = 2.6–3.3 with a continuum-to-noise ratio greater than 8, and we present a sample of five CoSLA candidates with τ
eff on 15 h
−1 Mpc greater than 4.5× the mean optical depth. At lower redshifts of z < 2.6, where the background quasar density is higher, the overdensity can be traced by intergalactic absorption groups using multiple sight lines with small angular separations. Our overdensity searches fully use the current and next generation of Lyα forest surveys, which cover a survey volume of >1 (h
−1 Gpc)3. Systems traced by CoSLAs will yield a uniform sample of the most massive overdensities at z > 2 to provide stringent constraints to models of structure formation.
NLTE ANALYSIS OF HIGH-RESOLUTION H-BAND SPECTRA. I. NEUTRAL SILICON*
Authors: Zhang Junbo , Shi Jianrong , Pan Kaike , Prieto Carlos Allende , Liu Chao 
Published: December 2016

ABSTRACT
We investigated the reliability of our silicon atomic model and the influence of non-local thermodynamical equilibrium (NLTE) on the formation of neutral silicon (Si i) lines in the near-infrared (near-IR) H-band. We derived the differential Si abundances for 13 sample stars with high-resolution H-band spectra from the Apache Point Observatory Galactic Evolution Experiment (APOGEE), as well as from optical spectra, both under local thermodynamical equilibrium (LTE) and NLTE conditions. We found that the differences between the Si abundances derived from the H-band and from optical lines for the same stars are less than 0.1 dex when the NLTE effects are included, and that NLTE reduces the line-to-line scatter in the H-band spectra for most sample stars. These results suggest that our Si atomic model is appropriate for studying the formation of H-band Si lines. Our calculations show that the NLTE corrections of the Si i
H-band lines are negative, i.e., the final Si abundances will be overestimated in LTE. The corrections for strong lines depend on surface gravity, and tend to be larger for giants, reaching ∼−0.2 dex in our sample, and up to ∼−0.4 dex in extreme cases of APOGEE targets. Thus, the NLTE effects should be included in deriving silicon abundances from H-band Si i lines, especially for the cases where only strong lines are available.
PSR J1301+0833: A KINEMATIC STUDY OF A BLACK-WIDOW PULSAR
Authors: Romani Roger W. , Graham Melissa L. , Filippenko Alexei V. , Zheng WeiKang 
Published: December 2016

ABSTRACT
We have obtained spectroscopic measurements of the P

s
= 1.8 ms, P

B
= 6.5 hr black-widow (BW) pulsar PSR J1301+0833 as part of a program to investigate optical companions of wind-shrouded pulsars. The derived radial-velocity amplitude (

) and inclination (

) imply a neutron star mass

, smaller (for similar fit assumptions) than that of the well-studied original BW pulsar PSR J1959+2048, which shares similar values of P

s
and P

B
. This fit, which assumes

, indicates a small heated region on the (anomalously faint) companion. With a free distance and full surface heating the best fit is statistically acceptable, but the large inferred

is inconsistent with the observed pulsar proper motion. Improved photometry and heating models will be needed to refine these measurements.
HIGH-ENERGY NON-THERMAL AND THERMAL EMISSION FROM GRB 141207A DETECTED BY FERMI
Authors: Arimoto Makoto , Asano Katsuaki , Ohno Masanori , Veres Péter , Axelsson Magnus , Bissaldi Elisabetta , Tachibana Yutaro , Kawai Nobuyuki 
Published: December 2016

ABSTRACT
A bright long gamma-ray burst GRB 141207A was observed by the Fermi Gamma-ray Space Telescope and detected by both instruments onboard. The observations show that the spectrum in the prompt phase is not well described by the canonical empirical Band function alone, and that an additional power-law component is needed. In the early phase of the prompt emission, a modified blackbody with a hard low-energy photon index (α = +0.2 to +0.4) is detected, which suggests a photospheric origin. In a finely time-resolved analysis, the spectra are also well fitted by the modified blackbody combined with a power-law function. We discuss the physical parameters of the photosphere such as the bulk Lorentz factor of the relativistic flow and the radius. We also discuss the physical origin of the extra power-law component observed during the prompt phase in the context of different models such as leptonic and hadronic scenarios in the internal shock regime and synchrotron emission in the external forward shock. In the afterglow phase, the temporal and spectral behaviors of the temporally extended high-energy emission and the fading X-ray emission detected by the X-Ray Telescope on-board Swift are consistent with synchrotron emission in a radiative external forward shock.
QUIESCENT PROMINENCES IN THE ERA OF ALMA: SIMULATED OBSERVATIONS USING THE 3D WHOLE-PROMINENCE FINE STRUCTURE MODEL
Authors: Gunár Stanislav , Heinzel Petr , Mackay Duncan H. , Anzer Ulrich 
Published: December 2016

ABSTRACT
We use the detailed 3D whole-prominence fine structure model to produce the first simulated high-resolution ALMA observations of a modeled quiescent solar prominence. The maps of synthetic brightness temperature and optical thickness shown in the present paper are produced using a visualization method for synthesis of the submillimeter/millimeter radio continua. We have obtained the simulated observations of both the prominence at the limb and the filament on the disk at wavelengths covering a broad range that encompasses the full potential of ALMA. We demonstrate here extent to which the small-scale and large-scale prominence and filament structures will be visible in the ALMA observations spanning both the optically thin and thick regimes. We analyze the relationship between the brightness and kinetic temperature of the prominence plasma. We also illustrate the opportunities ALMA will provide for studying the thermal structure of the prominence plasma from the cores of the cool prominence fine structure to the prominence–corona transition region. In addition, we show that detailed 3D modeling of entire prominences with their numerous fine structures will be important for the correct interpretation of future ALMA observations of prominences.
DISCOVERY OF A REDBACK MILLISECOND PULSAR CANDIDATE: 3FGL J0212.1+5320
Authors: Li Kwan-Lok , Kong Albert K. H. , Hou Xian , Mao Jirong , Strader Jay , Chomiuk Laura , Tremou Evangelia 
Published: December 2016

ABSTRACT
We present a multiwavelength study of the unidentified Fermi object, 3FGL J0212.1+5320. Within the 95% error ellipse, Chandra detects a bright X-ray source (i.e.,

erg cm−2 s−1) that has a low-mass optical counterpart (

and

K). A clear ellipsoidal modulation is shown in optical/infrared at 20.87 hr. The gamma-ray properties of 3FGL J0212.1+5320 are all consistent with that of a millisecond pulsar (MSP), suggesting that it is a γ-ray redback (RB) MSP binary with a low-mass companion filling ⪆64% of the Roche lobe. If confirmed, it will be an RB binary with one of the longest orbital periods known. Spectroscopic data taken in 2015 from the Lijiang observatory show no evidence of strong emission lines, revealing that the accretion is currently inactive (the rotation-powered pulsar state). This is consistent with the low X-ray luminosities (

erg s−1) and the possible X-ray modulation seen by Chandra and Swift. Considering that the X-ray luminosity and the high X-ray-to-γ-ray flux ratio (8%) are both comparable to those of the two known γ-ray transitional MSPs, we suspect that 3FGL J0212.1+5320 could be a potential target to search for future transition to the accretion active state.