bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Geometry of Cold, Metal-enriched Gas around Galaxies at z ∼ 1.2
Authors: Lundgren Britt F. , Creech Samantha , Brammer Gabriel , Kirse Nathan , Peek Matthew , Wake David , York Donald G. , Chisholm John , Erb Dawn K. , Kulkarni Varsha P. , Straka Lorrie , Tremonti Christy , van Dokkum Pieter 
Published: May 2021

Abstract
We present the first results from a Hubble Space Telescope Wide Field Camera 3/Infrared program, which obtained direct imaging and grism observations of galaxies near quasar sightlines with a high frequency of uncorrelated foreground Mg ii absorption. These highly efficient observations targeted 54 Mg ii absorbers along the line of sight to nine quasars at z
(qso ∼ 2. We find that 89% of the absorbers in the range of 0.64 < z < 1.6 can be spectroscopically matched to at least one galaxy with an impact parameter of less than 200 kpc and ∣Δz∣/(1 + z) < 0.006. We have estimated the star formation rates and measured structural parameters for all detected galaxies with impact parameters in the range of 7–200 kpc and star formation rates greater than 1.3 M
⊙ yr−1. We find that galaxies associated with Mg ii absorption have significantly higher mean star formation rates and marginally higher mean star formation rate surface densities compared to galaxies with no detected Mg ii. Nearly half of the Mg ii absorbers match more than one galaxy, and the mean equivalent width of the Mg ii absorption is found to be greater for groups, compared to isolated galaxies. Additionally, we observe a significant redshift evolution in the physical extent of Mg ii-absorbing gas around galaxies and evidence of an enhancement of Mg ii within 50° of the minor axis, characteristic of outflows, which persists to 80 kpc around the galaxies, in agreement with recent predictions from simulations.
Optical Analysis and Modeling of HD96670, a New Black Hole X-Ray Binary Candidate
Authors: Gomez Sebastian , Grindlay Jonathan E. 
Published: May 2021

Abstract
We report on optical observations and modeling of HD96670, a single-line spectroscopic binary in the Carina OB2 association. We collected 10 epochs of optical spectroscopy, and optical photometry on 17 nonconsecutive nights on the source. We construct a radial velocity curve from the spectra, and update the orbital period of the binary to be P = 5.28388 ± 0.00046 days. The spectra show oxygen and helium absorption, consistent with an O-type primary. We see no evidence for spectral lines from the secondary star in the binary. We model the optical light curve and radial velocity curve simultaneously using the Wilson–Devinney code and find a best-fit mass of

for the primary, and

for the secondary. An object of this mass is consistent with either a B-type star, or a black hole. Given that we see no absorption lines from the secondary, in combination with an observed hard power-law X-ray spectrum with Γ = 2.6 detected past 10 keV that may have been produced by wind accretion onto the secondary, we conclude that the secondary is most likely a black hole. We see asymmetrical helium lines with a shape consistent with the presence of a third star. If the secondary is indeed a black hole, this system would add to the small sample of only four possible black hole high mass X-ray binaries in the galaxy.
Magnetofrictional Modeling of an Erupting Pseudostreamer
Authors: Karna Nishu , Savcheva Antonia , Gibson Sarah , Tassev Svetlin , Reeves Katharine K. , DeLuca Edward E. , Dalmasse Kévin 
Published: May 2021

Abstract
In this study, we present the magnetic configuration of an erupting pseudostreamer observed on 2015 April 19, on the southwest limb of the Sun, with a prominence cavity embedded inside. The eruption resulted in a partial halo coronal mass ejection. The prominence eruption begins with a slow rise and then evolves to a fast-rise phase. We analyze this erupting pseudostreamer using the flux-rope insertion method and magnetofrictional relaxation to establish a sequence of plausible out-of-equilibrium magnetic configurations. This approach allows the direct incorporation of observations of structures seen in the corona (filament and cavity) to appropriately model the pseudostreamer based on SDO/HMI line-of-sight photospheric magnetograms. We also perform a topological analysis in order to determine the location of quasiseparatrix layers (QSLs) in the models, producing Q-maps to examine how the QSL locations progress in the higher iterations. We found that the axial flux in our best-fit unstable model was a factor of 20 times higher than we found in our marginally stable case. We computed the average magnetic field strength of the prominence and found that the unstable model exhibits twice the average field strength of the stable model. The eruption height from our modeling matches very well with the prominence eruption height measured from the AIA observation. The Q-maps derived from the model reproduce structures observed in LASCO/C2. Thus, the modeling and topological analysis results are fully consistent with the observed morphological features, implying that we have captured the large magnetic structure of the erupting filament in our magnetofrictional simulation.
Star Formation Histories from Spectral Energy Distributions and Color–magnitude Diagrams Agree: Evidence for Synchronized Star Formation in Local Volume Dwarf Galaxies over the Past 3 Gyr
Authors: Olsen Charlotte , Gawiser Eric , Iyer Kartheik , McQuinn Kristen B. W. , Johnson Benjamin D. , Telford Grace , Wright Anna C. , Broussard Adam , Kurczynski Peter 
Published: May 2021

Abstract
Star formation histories (SFHs) reveal physical processes that influence how galaxies form their stellar mass. We compare the SFHs of a sample of 36 nearby (D ⪅ 4 Mpc) dwarf galaxies from the ACS Nearby Galaxy Survey Treasury (ANGST), inferred from the color–magnitude diagrams (CMDs) of individually resolved stars in these galaxies, with those reconstructed by broadband spectral energy distribution (SED) fitting using the dense basis SED-fitting code. When comparing individual SFHs, we introduce metrics for evaluating SFH reconstruction techniques. For both the SED and CMD methods, the median normalized SFH of galaxies in the sample shows a period of quiescence at lookback times of 3–6 Gyr followed by rejuvenated star formation over the past 3 Gyr that remains active until the present day. To determine if these represent special epochs of star formation in the D <4 Mpc portion of the Local Volume, we break this ANGST dwarf galaxy sample into subsets based on specific star formation rate and spatial location. Modulo offsets between the methods of about 1 Gyr, all subsets show significant decreases and increases in their median normalized SFHs at the same epochs, and the majority of the individual galaxy SFHs are consistent with these trends. These results motivate further study of potential synchronized star formation quiescence and rejuvenation in the Local Volume as well as development of a hybrid method of SFH reconstruction that combines CMDs and SEDs, which have complementary systematics.
Searching for Local Counterparts of High-redshift Poststarburst Galaxies in Integral Field Unit Spectroscopic Surveys of Nearby Galaxies
Authors: Wu 吳柏 Po-Feng 鋒 
Published: May 2021

Abstract
Searching in the MaNGA IFU survey, I identify nine galaxies that have strong Balmer absorption lines and weak nebular emission lines measured from the spectra integrated over the entire IFU. The spectral features measured from the bulk of the stellar light make these galaxies local analogs of high-redshift spectroscopically selected poststarburst galaxies and thus proxies to understand the mechanisms producing poststarburst galaxies at high redshifts. I present the distributions of absorption line indices and emission line strengths, as well as the stellar kinematics of these local poststarburst galaxies. Almost all local poststarburst galaxies have central compact emission line regions at the central <1 kpc, mostly powered by weak star formation activities. The age-sensitive absorption line indices EW(Hδ) and D
n
4000 indicate that the stellar populations at the outskirts are older. Toy stellar population synthesis models suggest that the galaxies as a whole are experiencing a rapid decline of star formation with residual star formation activities at the centers. These features indicate that most poststarburst galaxies are the aftermath of highly dissipative processes that drive gas into centers, invoke centrally concentrated star formation, and then quench the galaxies. Meanwhile, when measurable, poststarburst galaxies have the directions of maximum stellar velocity gradients aligned with photometric major axes, which suggest against major mergers being the principal driving mechanism, while gas-rich minor mergers are plausible. While directly obtaining the same quality of spatially resolved spectra of high-redshift poststarburst galaxies is very difficult, finding proper local counterparts provides an alternative to understand quenching processes in the distant universe.
Evidence for an MHD Disk Wind via Optical Forbidden Line Spectroastrometry*
Authors: Whelan E. T. , Pascucci I. , Gorti U. , Edwards S. , Alexander R. D. , Sterzik M. F. , Melo C. 
Published: May 2021

Abstract
Spectroastrometry is used to investigate the low-velocity component (LVC) of the optical forbidden emission from the T Tauri stars RU Lupi and AS 205 N. Both stars also have high-velocity forbidden emission, which is tracing a jet. For AS 205 N, analysis reveals a complicated outflow system. For RU Lupi, the [O i] λ6300 and [S ii]λλ6716,6731 LV narrow component (NC) is offset along the same position angle (PA) as the high-velocity component but with a different velocity gradient than the jet, in that displacement from the stellar position along the rotation axis is decreasing with increasing velocity. From the LVC, NC, PA, and velocity gradient, it is inferred that the NC is tracing a wide-angled magnetohydrodynamic (MHD) disk wind. A photoevaporative wind is ruled out. This is supported by a comparison with a previous spectroastrometric study of the CO fundamental line. The decrease in offset with increasing velocity is interpreted as tracing an increase in the height of the wind with increasing disk radius. This is one of the first measurements of the spatial extent of the forbidden emission line LVC NC (∼40 au, 8 au for RU Lupi in the [S ii] λ6731 and [O i] λ6300 lines) and the first direct confirmation that the LVC narrow component can trace an MHD disk wind.
A New Fast Monte Carlo Code for Solving Radiative Transfer Equations Based on the Neumann Solution
Authors: Xiao-lin Yang , Jian-cheng Wang , Chu-yuan Yang , Zun-li Yuan 
Published: May 2021

Abstract
In this paper, we propose a new Monte Carlo radiative transport (MCRT) scheme, which is based completely on the Neumann series solution of the Fredholm integral equation. This scheme indicates that the essence of MCRT is the calculation of infinite terms of multiple integrals in the Neumann solution simultaneously. Under this perspective, we redescribe the MCRT procedure systematically, in which the main work amounts to choosing an associated probability distribution function for a set of random variables and the corresponding unbiased estimation functions. We select a relatively optimal estimation procedure that has a lower variance from an infinite number of possible choices, such as term-by-term estimation. In this scheme, MCRT can be regarded as a pure problem of integral evaluation, rather than as the tracing of random-walking photons. Keeping this in mind, one can avert some subtle intuitive mistakes. In addition, the δ functions in these integrals can be eliminated in advance by integrating them out directly. This fact, together with the optimal chosen random variables, can remarkably improve the Monte Carlo (MC) computational efficiency and accuracy, especially in systems with axial or spherical symmetry. An MCRT code, Lemon (Linear integral Equations’ Monte carlo solver based On the Neumann solution; the code is available on the GitHub codebase at https://github.com/yangxiaolinyn/Lemon, and version 2.0 is archived on Zenodo at https://doi.org/10.5281/zenodo.4686355), has been developed completely based on this scheme. Finally, we intend to verify the validation of Lemon; a suite of test problems mainly restricted to a flat spacetime has been reproduced, and the corresponding results are illustrated in detail.
The GBT Diffuse Ionized Gas Survey (GDIGS): Survey Overview and First Data Release
Authors: Anderson L. D. , Luisi Matteo , Liu Bin , Wenger Trey V. , Balser Dana. S. , Bania T. M. , Haffner L. M. , Linville Dylan J. , Mascoop J. L. 
Published: May 2021

Abstract
The Green Bank Telescope (GBT) Diffuse Ionized Gas Survey (GDIGS) traces ionized gas in the Galactic midplane by measuring 4–8 GHz radio recombination line (RRL) emission. The nominal survey zone is 32.°3 > ℓ > − 5°, ∣b∣ < 0.°5, but coverage extends above and below the plane in select fields and additionally includes the areas around W47 (ℓ ≃ 37.°5) and W49 (ℓ ≃ 43°). GDIGS simultaneously observes 22 Hnα (15 usable), 25 Hnβ (18 usable), and 8 Hnγ RRLs (all usable), as well as multiple molecular line transitions (including those of

, H2CO, and CH3OH). Here, we describe the GDIGS survey parameters and characterize the RRL data, focusing primarily on the Hnα data. We produce sensitive data cubes by averaging the usable RRLs, after first smoothing to a common spectral resolution of 0.5 km s−1 and a spatial resolution of 2.′65 for Hnα, 2.′62 for Hnβ, and 2.′09 for Hnγ. The average spectral noise per spaxel in the Hnα data cubes is ∼10 mK (∼5 mJy beam−1). This sensitivity allows GDIGS to detect RRLs from plasma throughout the inner Galaxy. The GDIGS Hnα data are sensitive to emission measures EM ≳ 1100 cm−6 pc, which corresponds to a mean electron density 〈n

e
〉 ≳ 30 cm−3 for a 1 pc path length or 〈n

e
〉 ≳ 1 cm−3 for a 1 kpc path length.
Association of Developmental Lumbar Spinal Canal Stenosis and Stunting
Authors: Muthuuri Jamlick Micheni 
Published: May 2021

Objective:
To determine a possible relationship between developmental lumbar spinal canal stenosis (DLSS) and stunting.

Background:
Stunting is due to failure of longitudinal length with shortened long bones. Stunted individuals have failure of growth of long bones implying a possibility of involvement of short and flat bones. The hypothesis in this study is that DLSS is part of a generalized skeletal dysplasia.

Materials and Methods:
This is a cross-sectional study (CSA) of 400 patients looking at the association of DLSS with stunting. The study compares the size of the spinal canal in individuals with stunting and those without stunting. Stunting was defined according to the WHO/UNICEF criteria of −2SD of the median height of the same population. The participants were divided into two types: those who were deemed stunted and those who were not. DLSS was similarly defined as −2SD of the relevant measured parameter. The study included skeletally mature patients between 18 and 60 years. All syndromic individuals, those with spine tumors and previous spine surgery, were excluded.

Results:
Four hundred individuals were sampled from a pool of 597 participants. One hundred and eight or 27% were stunted. The stunted individuals had statistically significantly shallow canal depths or anteroposterior diameters (11.2 ± 2.0 mm vs. 14.6 ± 2.6 mm, t(398) = −11.1, P < 0.001), and narrower canal widths (transverse diameters) (14.6 ± 3.3 mm vs. 18.8 ± 4.5 mm, t(398) = −8.1, P < 0.001) and smaller CSAs (134.0 ± 49.4 mm vs. 220.2 ± 82.0, t(398) = −9.4, P < 0.001) when compared to individuals with normal heights. Odds ratio was 10.

Conclusions:
Stunted individuals have smaller lumbar spinal canals when compared to nonstunted individuals. It can be concluded that developmental lumbar spinal canal stenosis is part of a generalized skeletal dysplasia.
A novel laparoscopic near-infrared fluorescence spectrum system with indocyanine green fluorescence overcomes limitations of near-infrared fluorescence image-guided surgery
Authors: Ebihara Yuma , Li Liming , Noji Takehiro , Kurashima Yo , Murakami Soichi , Shichinohe Toshiaki , Hirano Satoshi 
Published: May 2021

Background:
Near-infrared (NIR) fluorescence image-guided surgery (FIGS) introduces a revolutionary new approach to address this basic challenge in minimally invasive surgery. However, current FIGS systems have some limitations – the infrared rays cannot detect and visualise thick tissues with low concentrations of the fluorescent agent. We established a novel laparoscopic fluorescence spectrum (LFS) system using indocyanine green (ICG) fluorescence to overcome these limitations.

Materials and Methods:
Bovine serum albumin (BSA) was conjugated to ICG, and the mixtures were serially diluted at 5 × 10−8–5 × 10−1 mg/mL. We used the LFS system and a NIR camera system (NLS; SHINKO OPTICAL CO., LTD Tokyo, Japan) to determine the optical dilution for the fluorescence detection. BSA was conjugated to ICG (5.0 × 10−2 mg/mL) and used to coat the clips. We attempted to identify the fluorescence-coated clip from the serosal side of the cadaveric porcine stomach tissues using the LFS system and the NIR camera system. We measured the depth of the cadaveric porcine stomach wall at the thickest part that could be confirmed.

Results:
We could not visualise fluorescence concentrations <2.5 × 10−3 mg/mL using the NIR camera system. The spectrum was detected at a concentration <2.5 × 10−3 mg/mL. We were able to identify the spectrum of ICG (829 nm) to a 13-mm depth of cadaveric porcine stomach wall by using the LFS system but could not identify the same with the NIR camera system regardless of wall thickness.

Conclusions:
The novel LFS system with NIR fluorescence imaging in this ex vivo and cadaveric porcine model was confirmed useful at deeper depths and lower concentrations. Based on these findings, we anticipate that the LFS system can be integrated and routinely used in minimally invasive surgery.
Epidemiology Profile and Outcomes of Oral Potentially Malignant Disorders among Different Geographic Regions of Taiwan
Authors: Chiu Sheng-Fu , Ho Chung-Han , Chen Yi-Chen , Wu Li-Wha , Chen Yuh-Ling , Wu Jer-Horng , Wu Wei-Sheng , Hung Hui-Kun , Chiang Wei-Fan 
Published: May 2021

Background:
The malignant transformation of oral potentially malignant disorders (OPMDs) is a potential cause of oral cancers. However, epidemiological studies on malignant transformation of OPMDs are lacking. The present study is aimed to investigate the percentage of OPMD in the oral mucosal screening database and the malignant transformation (%) across different regions of Taiwan.

Methods:
We determined the cases of malignant transformation of OPMD to oral cancers during the 2-year follow-up by the oral mucosal screening database and the cancer registry database contained in the National Health Insurance Research Database. Patients with oral cancer history before OPMD diagnosis were excluded from the study. We collected data including clinical diagnosis, biopsy result, follow-up, and place of residence of the patient. The most widely used definition from the Council for Economic Planning and Development in Taiwan was used in this study for the classification into Southern, Northern, Eastern, and Western Taiwan regions. Differences in the malignant transformation (%) and ranking between regions were evaluated using analysis of variance test.

Results:
Chiayi city located in Southern Taiwan has the highest percentage of OPMD in oral screening citizen. The percentage of OPMD in the oral mucosal screening database was highest in Southern Taiwan and lowest in Eastern Taiwan; however, the malignant transformation (%) was highest in the Eastern Taiwan and lowest in Northern Taiwan.

Conclusion:
Dentists and otolaryngologists in Southern Taiwan, especially Chiayi city, should be cautious when screening the patient because of the high percentage of OPMD in oral mucosal screening database. The percentage of OPMD in the oral mucosal screening database and the malignant transformation (%) are different among the different regions in Taiwan. Further research is needed to clarify the reasons for the different malignant transformation (%) between regions.
Surveillance of Human Guinea Worm in Chad, 2010–2018
Authors: Guagliardo Sarah Anne J. , Ruiz-Tiben Ernesto , Hopkins Donald R. , Weiss Adam J. , Ouakou Philippe Tchindebet , Zirimwabagabo Hubert , Unterwegner Karmen , Tindall Dillon , Cama Vitaliano A. , Bishop Henry , Sapp Sarah G. H. , Roy Sharon L. 
Published: May 2021

Abstract.The total number of Guinea worm cases has been reduced by 99.9% since the mid-1980s when the eradication campaign began. Today, the greatest number of cases is reported from Chad. In this report, we use surveillance data collected by the Chad Guinea Worm Eradication Program to describe trends in human epidemiology. In total, 114 human cases were reported during the years 2010–2018, with highest rates of containment (i.e., water contamination prevented) in the years 2013, 2014, 2016, and 2017 (P < 0.0001). Approximately half of case-patients were female, and 65.8% of case-patients were aged 30 years or younger (mean: 26.4 years). About 34.2% of case-patients were farmers. Cases were distributed across many ethnicities, with a plurality of individuals being of the Sara Kaba ethnicity (21.3%). Most cases occurred between the end of June and the end of August and were clustered in the Chari Baguirmi (35.9%) and Moyen Chari regions (30.1%). Cases in the northern Chari River area peaked in April and in August, with no clear temporal pattern in the southern Chari River area. History of travel within Chad was reported in 7.0% of cases, and male case-patients (12.5%) were more likely than female case-patients (1.7%) to have reported a history of travel (P = 0.03). Our findings confirm that human Guinea worm is geographically disperse and rare. Although the proportion of case-patients with travel history is relatively small, this finding highlights the challenge of surveillance in mobile populations in the final stages of the global eradication campaign.
Hydrogeological evaluation of geological formations in Ashanti Region, Ghana
Authors: Appiah-Adjei E. K. , Osei-Nuamah I. 
Published: May 2021

The success of groundwater exploitation in an area largely depends on prior knowledge of existing hydrogeological parameters such as borehole yield, overburden thickness, depth of boreholes, static water level, specific capacity and the quality of water. This study, therefore, employed Geographical Information System to assess some of these hydrogeological parameters in the Ashanti Region using the ordinary kriging interpolation method. Data on 2,788 drilled boreholes in the region were used and the assessment focused on the various geological formations in the region that comprised the Birimian, Granitoids, Tarkwaian and Voltaian formations. The study results indicate that the Birimian formation is generally within medium to high yielding potential zones (30 – 60 l/min or higher) with a high drilling success rate of 91% and average borehole depth of 53 m. The Granitoids are, mostly, within the low yielding zone (< 30 l/min) with isolated high yielding boreholes and have average borehole depth and drilling success rate of 50 m and 72 % respectively. The Tarkwaian formation, on other hand, is within the medium yield zone with a drilling success rate of 80 % whilst the Voltaian formation is mainly classified to fall within low yield zone with about 60% success rate although significant high yield zones occur within the sandstone formation underlying its westernmost part in the region. Groundwater in the region is generally potable except in a few locations within the Birimian and ranitoids,where there are problems with levels of iron, nitrate, manganese and pH. Keywords: Groundwater; Hydrogeological parameters; Geological formations; Geographical Information System; Ashanti Region