bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Mass-Luminosity Relation From Binaries
Authors: Latham David W. 
Published: June 2021

What is known about the masses of main-sequence stars from the analysis of binary orbits? Double-lined eclipsing binaries are the main source of very precise stellar masses and radii (e.g. Andersen 1997), contributing more than 100 determinations with better than 2% precision over the range 0.6 to 20 Mʘ. For lower-mass stars we are forced to turn to nearby systems with astrometric orbits (e.g. Henry et al. 1993). Not only is the number of good mass determinations from such systems smaller, but also the precision is generally poorer. We are approaching an era when interferometers should have a major impact by supplying good astrometric orbits for dozens of double-lined systems. Already we are beginning to see the sorts of results to expect from this (e.g. Torres et al. 1997).Figure 1. Mass vs. absolute V magnitude for eclipsing binaries (circles) and nearby astrometric binaries (squares)Figure 1 is an updated version of a diagram presented by Henry et al. (1993, their Figure 2). It shows the general run of mass determinations from about 10 Mʘ down to the substellar limit near 0.075 Mʘ. Ninety of the points in Figure 1 are for eclipsing binary masses from Andersen’s review (1991) and are plotted as open circles. The results for eclipsing binaries published since 1991 are plotted as 30 filled circles, adopting the same limit of 2% for the mass precision. In most cases the uncertainties are similar to the size of the symbols. Especially noteworthy is the pair of new points for CM Draconis (Metcalfe et al. 1996) with masses near 0.25 Mʘ. Together with the points for YY Geminorum near 0.6 Mʘ, these are the only M dwarfs that have precise mass determinations. For the most part we are forced to rely on nearby stars with astrometric orbits, to fill in the M dwarf region of the diagram. We have used filled squares in Figure 1 for 29 such systems from Henry et al. (1993), updated using 14 new parallaxes from Hipparcos and 4 from the new Yale Parallax Catalog (1995). Gliese 508 is not included, because it is now known to be a triple, while Gliese 67AB, 570BC, and 623AB are not included because there are not yet any direct measurements of the V magnitude difference for these systems.
Dwarf Carbon Star Model Atmospheres And Synthetic Spectra
Authors: Jørgensen U.G. , Borysow A. , Höfner S. , Wing R.F. 
Published: June 2021

Dwarf carbon (dC) stars are believed to be main-sequence stars which have received carbon-rich material from a former AGB carbon star companion. We have computed model atmospheres, synthetic spectra, and colours for dC stars and compared them with observations. Our models are computed with an updated version of the MARCS code (Jørgensen et al. 1992, A&A 261, 263) and include atomic and molecular line blanketing, grain formation, and collision-induced absorption (CIA) processes (Borysow et al. 1997, A&A 324, 185). The models assume hydrostatic equilibrium, which for giant stars (i.e., high luminosity and low gravity) would be inconsistent with the inclusion of dust. Typical gravities of dC stars are, however, considerably larger than the acceleration due to radiation pressure even on dust grains with a relatively high absorption coefficient.For the cooler solar metallicity models, grain formation can be substantial, but it depends strongly on the assumed type of dust. In a test model of Teff = 2800 K, C/O = 1.17, and log(g) = 5, 1% of the free carbon (i.e., that not bound in CO molecules) condensed when the dust was assumed to be amorphous carbon, whereas as much as 30% condensed when nano-diamonds (of the extra-solar form which are abundant in carbonaceous chondrite meteorites and are believed to have formed in stellar outflows) were allowedfor. This difference in degree of condensation is due to the very small diamond opacity compared to that of amorphous carbon. In both cases, however, the main effect of the dust was a 400 K heating of the surface layers. The dust itself is not clearly visible in the synthetic spectrum, but the heating and correspondingly reduced molecular partial pressures cause a weakeningof spectral features in the 3μm region (due mainly to reduced C2H2 abundance in the upper layers) and reduced CO fundamental and first overtone band intensities.
Introduction
Authors: Fairall A.P. 
Published: June 2021

As we approach the 21st Century, enormous technical advances are being made in the acquisition of galaxy redshifts. This Joint Discussion offers a perspective on those advances and the associated redshift surveys. It is representative, but by no means all inclusive.My introduction offers some historical background, against which the new methods and achievements can be measured.Redshift surveys tells us about the spatial distribution and evolution of galaxies. Yet the study of large-scale structures in the distribution of galaxies goes back further than one might imagine. The first accurate description of the Virgo Supercluster was given by John Herschel in the mid-19thCentury. To paraphrase Sir John, “Virgo is the central condensation of a roughly spherical cluster of nebulae - our system lies outside the denser part of the cluster, but is involved with its outlying members - forming an element of some one of its protuberances or branches”.Victorian science might have beaten Hubble had more people believed John Herschel - and had he himself more confidence in his interpretation. Few were prepared to accept the ‘Island Universe’ theory that it implied, and strong criticism followed. Moreover, Herschel was very reluctant to go against the beliefs of his revered father, William Herschel, who, though once believing in the ‘Island Universes’, had in later life accepted that all nebulae were somehow gaseous condensations in our system. Consequently, even John Herschel’s textbook still stated the older, incorrect interpretation.
Electronic Preprints
Authors: Payne Harry E. 
Published: June 2021

AbstractPaper preprints are in decline in astronomy, while the use of electronic preprints is on the rise, mainly via the LANL astroph preprint archive. I discuss the decline of the paper preprint, some preprint servers available on the Web and some general electronic preprint issues, the astropharchive and its response to these issues, and alternatives for the future of electronic preprints.
Spectroscopic Radial Velocities: Photospheric Lineshifts Calibrated By Hipparcos
Authors: Gullberg D. , Dravins D. 
Published: June 2021

Wavelengths of stellar spectral lines depend not only on the star’s motion. Until recently, accurate studies of shifts not caused by radial motion were feasible only for the Sun. Solar lineshifts are interpreted as gravitational redshift (636 m/s) and convective blueshifts (~ 400 m/s; caused by velocity-brightness correlations). In other stars, such effects may be greater (Dravins & Nordlund 1990). Accurate astrometric radial velocities are now available from Hipparcos (Dravins et al. 1997a; 1997b), permitting studies of such shifts also in some other stars.For such stars in the open clusters of Hyades, Ursa Major and Coma Berenices, a spectroscopic program is in progress, analyzing wavelength shifts in groups of lines with different strengths, excitation potentials, etc., using the ELODIE high-precision radial-velocity instrument (Baranne et al. 1996) at Haute-Provence Observatory.
Analysis of the Hipparcos Sample of Eclipsing Binaries Parallaxes And Multiplicity
Authors: Oblak E. , Kurpinska-Winiarska M. , Kundera T. , Zola S. , Dworak T.Z. 
Published: June 2021

The Hipparcos astrometric satellite observed 993 known eclipsing binaries. Prom 1048 eclipsing binaries of the Brancewicz and Dworak ’s catalogue (1980), there are only 368 observed by Hipparcos, as the others are too faint.On the basis of these common stars, we have undertaken the comparison ofthe satellite parallaxes with the photometric ones. We obtain a good agreement between the two systems with a mean dispersion of 5 mas. The greatest dispersion is for the goup of eclipsing binaries of the EW type. The eclipsing binaries of this group have a mass-luminosity relation different from those of the main sequence stars.An inadequate knowledge of the component spectra of an eclipsing binary seems to be one of the most important cause of discrepancies. For some brightest stars, the new Hipparcos trigonometric parallaxes differ very significantly from those previously known from ground based measurements. It seems that the presence of a close visual components causes statistically an underestimation of photometric or overestimation of Hipparcos parallaxes.172 Hipparcos eclipsing binaries have a close visual component, generally less than 10 arcseconds apart. The list of these stars for various stellar groups and a brief analysis are presented.
Systematic Mapping of Upper Mantle Seismic Discontinuities Beneath Northeastern North America
Authors: Li Yiran , Levin Vadim , Nikulin Alex , Chen Xiaoran 
Published: June 2021

AbstractAbrupt velocity gradients in the upper mantle, detectable by receiver functions (RF) techniques, have been known to exist down to the depths of ∼110 km beneath northeastern North America. Comparisons with the surface wave velocity models have designated some negative velocity gradients (NVGs) as the lithosphere‐asthenosphere boundary (LAB), delineating a relatively thin lithosphere beneath this region. This work presents a systematic survey of upper mantle layering in seismic properties using P‐S RF analysis at 62 long‐running sites with dense lateral sampling. We examine both radial and transverse component RF for indicators of seismic anisotropy and adopt the notion of seismic attributes, utilized in active‐source seismology, to characterize the spatial distribution of directionally variant and invariant signal components. We confirm a widespread presence of NVGs at depths 60–100 km throughout the region, consistent with previous studies using mode‐converted body waves. We also find numerous converting boundaries that reflect changes in directional variation (anisotropy) of seismic velocity, indicating complexity of rock texture in the upper mantle. Some of these boundaries appear as deep as 185 km, implying that the lithosphere extends much deeper than the widespread NVGs would suggest. In this, our results agree with recent estimates of the lithospheric thickness in thermodynamically consistent models combining seismic, gravity, and heat flow constraints.
X-ray-charged bright persistent luminescence in NaYF4:Ln3+@NaYF4 nanoparticles for multidimensional optical information storage
Authors: Zhuang Yixi , Chen Dunrong , Chen Wenjing , Zhang Wenxing , Su Xin , Deng Renren , An Zhongfu , Chen Hongmin , Xie Rong-Jun 
Published: June 2021

AbstractNaYF4:Ln3+, due to its outstanding upconversion characteristics, has become one of the most important luminescent nanomaterials in biological imaging, optical information storage, and anticounterfeiting applications. However, the large specific surface area of NaYF4:Ln3+ nanoparticles generally leads to serious nonradiative transitions, which may greatly hinder the discovery of new optical functionality with promising applications. In this paper, we report that monodispersed nanoscale NaYF4:Ln3+, unexpectedly, can also be an excellent persistent luminescent (PersL) material. The NaYF4:Ln3+ nanoparticles with surface-passivated core–shell structures exhibit intense X-ray-charged PersL and narrow-band emissions tunable from 480 to 1060 nm. A mechanism for PersL in NaYF4:Ln3+ is proposed by means of thermoluminescence measurements and host-referred binding energy (HRBE) scheme, which suggests that some lanthanide ions (such as Tb) may also act as effective electron traps to achieve intense PersL. The uniform and spherical NaYF4:Ln3+ nanoparticles are dispersible in solvents, thus enabling many applications that are not accessible for traditional PersL phosphors. A new 3-dimensional (2 dimensions of planar space and 1 dimension of wavelength) optical information-storage application is demonstrated by inkjet-printing multicolor PersL nanoparticles. The multicolor persistent luminescence, as an emerging and promising emissive mode in NaYF4:Ln3+, will provide great opportunities for nanomaterials to be applied to a wider range of fields.
Western diet leads to aging-related tumorigenesis via activation of the inflammatory, UPR, and EMT pathways
Authors: Imbroisi Filho Ricardo , Ochioni Alan C. , Esteves Amanda M. , Leandro João G. B. , Demaria Thainá M. , Sola-Penna Mauro , Zancan Patricia 
Published: June 2021

AbstractAmong the principal causative factors for the development of complications related to aging is a diet rich in fats and sugars, also known as the Western diet. This diet advocates numerous changes that might increase the susceptibility to initiate cancer and/or to create a tissue microenvironment more conducive to the growth of malignant cells, thus favoring the progression of cancer and metastasis. Hypercaloric diets in general lead to oxidative stress generating reactive oxygen species and induce endoplasmic reticulum stress. Our results demonstrate that mice bearing tumors fed with a Western diet presented bigger tumor mass with increased insulin sensitivity in these tissues. Several markers of insulin signaling, such as AKT phosphorylation and mTOR pathway, are promoted in tumors of Western diet-fed animals. This process is associated with increased macrophage infiltration, activation of unfolded protein response pathway, and initiation of epithelial–mesenchymal transition (EMT) process in these tumor tissues. Summing up, we propose that the Western diet accelerates the aging-related processes favoring tumor development.
A veil of ignorance can promote fairness in a mammal society
Authors: Marshall H. H. , Johnstone R. A. , Thompson F. J. , Nichols H. J. , Wells D. , Hoffman J. I. , Kalema-Zikusoka G. , Sanderson J. L. , Vitikainen E. I. K. , Blount J. D. , Cant M. A. 
Published: June 2021

AbstractRawls argued that fairness in human societies can be achieved if decisions about the distribution of societal rewards are made from behind a veil of ignorance, which obscures the personal gains that result. Whether ignorance promotes fairness in animal societies, that is, the distribution of resources to reduce inequality, is unknown. Here we show experimentally that cooperatively breeding banded mongooses, acting from behind a veil of ignorance over kinship, allocate postnatal care in a way that reduces inequality among offspring, in the manner predicted by a Rawlsian model of cooperation. In this society synchronized reproduction leaves adults in a group ignorant of the individual parentage of their communal young. We provisioned half of the mothers in each mongoose group during pregnancy, leaving the other half as matched controls, thus increasing inequality among mothers and increasing the amount of variation in offspring birth weight in communal litters. After birth, fed mothers provided extra care to the offspring of unfed mothers, not their own young, which levelled up initial size inequalities among the offspring and equalized their survival to adulthood. Our findings suggest that a classic idea of moral philosophy also applies to the evolution of cooperation in biological systems.
Transforming biorefinery designs with ‘Plug-In Processes of Lignin’ to enable economic waste valorization
Authors: Liu Zhi-Hua , Hao Naijia , Wang Yun-Yan , Dou Chang , Lin Furong , Shen Rongchun , Bura Renata , Hodge David B. , Dale Bruce E. , Ragauskas Arthur J. , Yang Bin , Yuan Joshua S. 
Published: June 2021

AbstractBiological lignin valorization has emerged as a major solution for sustainable and cost-effective biorefineries. However, current biorefineries yield lignin with inadequate fractionation for bioconversion, yet substantial changes of these biorefinery designs to focus on lignin could jeopardize carbohydrate efficiency and increase capital costs. We resolve the dilemma by designing ‘plug-in processes of lignin’ with the integration of leading pretreatment technologies. Substantial improvement of lignin bioconversion and synergistic enhancement of carbohydrate processing are achieved by solubilizing lignin via lowering molecular weight and increasing hydrophilic groups, addressing the dilemma of lignin- or carbohydrate-first scenarios. The plug-in processes of lignin could enable minimum polyhydroxyalkanoate selling price at as low as $6.18/kg. The results highlight the potential to achieve commercial production of polyhydroxyalkanoates as a co-product of cellulosic ethanol. Here, we show that the plug-in processes of lignin could transform biorefinery design toward sustainability by promoting carbon efficiency and optimizing the total capital cost.
Self-assembly of an anion receptor with metal-dependent kinase inhibition and potent in vitro anti-cancer properties
Authors: Allison Simon J. , Bryk Jaroslaw , Clemett Christopher J. , Faulkner Robert A. , Ginger Michael , Griffiths Hollie B. S. , Harmer Jane , Jane Owen-Lynch P. , Pinder Emma , Wurdak Heiko , Phillips Roger M. , Rice Craig R. 
Published: June 2021

AbstractOne topical area of supramolecular chemistry is the binding of anionic species but despite the importance of anions in diverse cellular processes and for cancer development, anion receptors or ‘binders’ have received little attention as potential anti-cancer therapeutics. Here we report self-assembling trimetallic cryptands (e.g. [L2(Metal)3]6+ where Metal = Cu2+, Zn2+ or Mn2+) which can encapsulate a range of anions and which show metal-dependent differences in chemical and biological reactivities. In cell studies, both [L2Cu3]6+ and [L2Zn3]6+ complexes are highly toxic to a range of human cancer cell lines and they show significant metal-dependent selective activity towards cancer cells compared to healthy, non-cancerous cells (by up to 2000-fold). The addition of different anions to the complexes (e.g. PO43ˉ, SO42ˉ or PhOPO32ˉ) further alters activity and selectivity allowing the activity to be modulated via a self-assembly process. The activity is attributed to the ability to either bind or hydrolyse phosphate esters and mechanistic studies show differential and selective inhibition of multiple kinases by both [L2Cu3]6+ and [L2Zn3]6+ complexes but via different mechanisms.
TCF21+ mesenchymal cells contribute to testis somatic cell development, homeostasis, and regeneration in mice
Authors: Shen Yu-chi , Shami Adrienne Niederriter , Moritz Lindsay , Larose Hailey , Manske Gabriel L. , Ma Qianyi , Zheng Xianing , Sukhwani Meena , Czerwinski Michael , Sultan Caleb , Chen Haolin , Gurczynski Stephen J. , Spence Jason R. , Orwig Kyle E. , Tallquist Michelle , Li Jun Z. , Hammoud Saher Sue 
Published: June 2021

AbstractTesticular development and function rely on interactions between somatic cells and the germline, but similar to other organs, regenerative capacity declines in aging and disease. Whether the adult testis maintains a reserve progenitor population remains uncertain. Here, we characterize a recently identified mouse testis interstitial population expressing the transcription factor Tcf21. We found that TCF21lincells are bipotential somatic progenitors present in fetal testis and ovary, maintain adult testis homeostasis during aging, and act as potential reserve somatic progenitors following injury. In vitro, TCF21lincells are multipotent mesenchymal progenitors which form multiple somatic lineages including Leydig and myoid cells. Additionally, TCF21+cells resemble resident fibroblast populations reported in other organs having roles in tissue homeostasis, fibrosis, and regeneration. Our findings reveal that the testis, like other organs, maintains multipotent mesenchymal progenitors that can be potentially leveraged in development of future therapies for hypoandrogenism and/or infertility.
Thermal state and evolving geodynamic regimes of the Meso- to Neoarchean North China Craton
Authors: Sun Guozheng , Liu Shuwen , Cawood Peter A. , Tang Ming , van Hunen Jeroen , Gao Lei , Hu Yalu , Hu Fangyang 
Published: June 2021

AbstractConstraining thickness and geothermal gradient of Archean continental crust are crucial to understanding geodynamic regimes of the early Earth. Archean crust-sourced tonalitic–trondhjemitic–granodioritic gneisses are ideal lithologies for reconstructing the thermal state of early continental crust. Integrating experimental results with petrochemical data from the Eastern Block of the North China Craton allows us to establish temporal–spatial variations in thickness, geothermal gradient and basal heat flow across the block, which we relate to cooling mantle potential temperature and resultant changing geodynamic regimes from vertical tectonics in the late Mesoarchean (~2.9 Ga) to plate tectonics with hot subduction in the early to late Neoarchean (~2.7–2.5 Ga). Here, we show the transition to a plate tectonic regime plays an important role in the rapid cooling of the mantle, and thickening and strengthening of the lithosphere, which in turn prompted stabilization of the cratonic lithosphere at the end of the Archean.
Cretaceous bird with dinosaur skull sheds light on avian cranial evolution
Authors: Wang Min , Stidham Thomas A. , Li Zhiheng , Xu Xing , Zhou Zhonghe 
Published: June 2021

AbstractThe transformation of the bird skull from an ancestral akinetic, heavy, and toothed dinosaurian morphology to a highly derived, lightweight, edentulous, and kinetic skull is an innovation as significant as powered flight and feathers. Our understanding of evolutionary assembly of the modern form and function of avian cranium has been impeded by the rarity of early bird fossils with well-preserved skulls. Here, we describe a new enantiornithine bird from the Early Cretaceous of China that preserves a nearly complete skull including the palatal elements, exposing the components of cranial kinesis. Our three-dimensional reconstruction of the entire enantiornithine skull demonstrates that this bird has an akinetic skull indicated by the unexpected retention of the plesiomorphic dinosaurian palate and diapsid temporal configurations, capped with a derived avialan rostrum and cranial roof, highlighting the highly modular and mosaic evolution of the avialan skull.
Mn2+ induced significant improvement and robust stability of radioluminescence in Cs3Cu2I5 for high-performance nuclear battery
Authors: Li Xiaoming , Chen Jiaxin , Yang Dandan , Chen Xi , Geng Dongling , Jiang Lianfu , Wu Ye , Meng Cuifang , Zeng Haibo 
Published: June 2021

AbstractFluorescent type nuclear battery consisting of scintillator and photovoltaic device enables semipermanent power source for devices working under harsh circumstances without instant energy supply. In spite of the progress of device structure design, the development of scintillators is far behind. Here, a Cs3Cu2I5: Mn scintillator showing a high light yield of ~67000 ph MeV−1 at 564 nm is presented. Doping and intrinsic features endow Cs3Cu2I5: Mn with robust thermal stability and irradiation hardness that 71% or >95% of the initial radioluminescence intensity can be maintained in an ultra-broad temperature range of 77 K-433 K or after a total irradiation dose of 2590 Gy, respectively. These superiorities allow the fabrication of efficient and stable nuclear batteries, which show an output improvement of 237% respect to the photovoltaic device without scintillator. Luminescence mechanisms including self-trapped exciton, energy transfer, and impact excitation are proposed for the anomalous dramatic radioluminescence improvement. This work will open a window for the fields of nuclear battery and radiography.