bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating the Ages of FGK Dwarf Stars through the Use of GALEX FUV Magnitudes
Authors: Crandall Sara , Smith Graeme H. , Subramonian Arjun , Ho Kelly , Cochrane Evelyn M. 
Published: October 2020

Abstract
Stellar age cannot be directly measured, yet age determinations are fundamental to understanding the evolution of stars, planets, and galaxies. The work presented here builds upon the idea of a stellar-activity age. We utilized far-ultraviolet (FUV) photometry acquired by the Galaxy Evolution Explorer (GALEX) space telescope as an indicator of chromospheric activity to infer ages of late-F, G, and K type dwarf stars. We derived a purely empirical correlation between FUV magnitudes and stellar age in conjunction with (B − V) color. Our attention is restricted to Sun-like stars with color range

and absolute magnitude range 4.3 ≤ M
V ≤ 5.3. The correlation is defined in terms of a FUV-excess parameter

. We related stellar age, τ, to Q through the relation

, where a and b are fit parameters and functions of (B − V). This correlation is functional up to 6 Gyr for FGK dwarfs. With such a correlation, one only needs Johnson (B − V) and FUV measurements to estimate the stellar age for Population i dwarf stars of solar-like temperature and metallicity. Such a calibration has utility in population studies of FGK dwarfs for further understanding of the chemical evolution of the Milky Way. As an illustration of one such application, we have constructed activity and FUV–age distributions for a sample of thin and thick disk stars, as distinguished by their chemical abundances. Considerable overlap is found between the activity distribution and age range of the two populations. We discuss the possibility that some high-[α/Fe] thick disk stars were formed as a result of the accretion of dwarf galaxies as recently as 4 Gyr ago.
Swift/BAT and RXTE/ASM Observations of the 35 day X-Ray Cycle of Hercules X-1
Authors: Leahy Denis , Wang Yuyang 
Published: October 2020

Abstract
Swift/BAT and RXTE/ASM observations have monitored the X-ray binary system Her X-1 for approximately 14.5 yr each, and both were monitoring Her X-1 for a period of ∼5.5 yr. Here we study the 35 day cycle using these observations. Using a cross-correlation method we find the times of peaks of the 35 day cycles for ∼150 cycles observed by Swift/BAT and ∼150 cycles observed by RXTE/ASM. These cycles include ∼60 observed with both instruments. The noise level of the RXTE/ASM measurements is larger than that of Swift/BAT, resulting in larger uncertainty in peak times. The distribution of 35 day cycle lengths can be fit with a Gaussian with mean 34.79 days and σ of 1.1 days. The distribution of orbital phases of 35 day cycle peaks is well fit by a uniform distribution, with 76% of the cycles, plus a Gaussian distribution peaked at orbital phase ∼0.5, with 24% of the cycles. We construct the long-term average 35 day lightcurve in the 15–50 keV band from Swift/BAT, and in the 2–12 keV band from RXTE/ASM. The high-energy band shows more variability in the short high state and the low-energy band shows more variability in the main high state. This is consistent with a precessing accretion disk model as the cause of the 35 day cycle.
The Massive and Distant Clusters of WISE Survey. X. Initial Results from a Sunyaev–Zeldovich Effect Study of Massive Galaxy Clusters at z > 1 Using MUSTANG2 on the GBT
Authors: Dicker Simon R. , Romero Charles E. , Mascolo Luca Di , Mroczkowski Tony , Sievers Jonathan , Moravec Emily , Bhandarkar Tanay , Brodwin Mark , Connor Thomas , Decker Bandon , Devlin Mark , Gonzalez Anthony H. , Lowe Ian , Mason Brian S. , Sarazin Craig , Stanford Spencer A. , Stern Daniel , Thongkham Khunanon , Wylezalek Dominika , Zago Fernando 
Published: October 2020

Abstract
The properties of galaxy clusters as a function of redshift can be utilized as an important cosmological tool. We present initial results from a program of follow-up observations of the Sunyaev–Zeldovich effect (SZE) in high-redshift galaxy clusters detected by the Massive and Distant Clusters of WISE Survey (MaDCoWS) which uses infrared data from the Wide-field Infrared Survey (WISE) instrument. Using typical on-source integration times of 3–4 hr per cluster, MUSTANG2 on the Green Bank Telescope was able to measure strong detections of SZE decrements and statistically significant masses on 14 out of 16 targets. On the remaining two, weaker (3.7σ) detections of the SZE signal and strong upper limits on the masses were obtained. In this paper we present masses and pressure profiles of each target and outline the data analysis used to recover these quantities. Of the clusters with strong detections, three show significantly flatter pressure profiles while, from the MUSTANG2 data, five others show signs of disruption at their cores. However, outside of the cores of the clusters, we were unable to detect significant amounts of asymmetry. Finally, there are indications that the relationship between optical richness used by MaDCoWS and SZE-inferred mass may be significantly flatter than indicated in previous studies.
Empirical Test for Relativistic Kinetic Theories Based on the Sunyaev–Zel’dovich Effect
Authors: Molnar S. M. , Godfrey J. 
Published: October 2020

Abstract
We propose a new method to determine the electron velocity (EV) distribution function in the intracluster gas (ICG) in clusters of galaxies based on the frequency dependence of the Sunyaev–Zel’dovich (SZ) effect. It is generally accepted that the relativistic equilibrium EV distribution is the one suggested by Jüttner. However, there is an ongoing debate on the foundation of relativistic kinetic theory, and other distributions have also been proposed. The mildly relativistic ICG provides a unique laboratory to test relativistic kinetic theories. We carried out Monte Carlo simulations to generate SZ signal from a single-temperature gas assuming the Jüttner EV distribution assuming a few percent errors. We fitted SZ models based on nonrelativistic Maxwellian, and its two relativistic generalizations, the Jüttner and modified Jüttner distributions. We found that a 1% error in the SZ signal is sufficient to distinguish between these distributions with high significance based on their different best-fit temperatures. However, in any line of sight (LOS) in a cluster, the ICG contains a range of temperatures. Using our N-body/hydrodynamical simulation of a merging galaxy cluster and assuming a 1% error in the SZ measurements in an LOS through a bow shock, we find that it is possible to distinguish between Jüttner and modified Jüttner distributions with high significance. Our results suggest that deriving ICG temperatures from fitting to SZ data assuming different EV distribution functions and comparing them to the temperature in the same cluster obtained using other observations would enable us to distinguish between the different distributions.
Evolution of the Density PDF in Star-forming Clouds: The Role of Gravity
Authors: Jaupart Etienne , Chabrier Gilles 
Published: October 2020

Abstract
We derive an analytical theory of the PDF of density fluctuations in supersonic turbulence in the presence of gravity in star-forming clouds. The theory is based on a rigorous derivation of a combination of the Navier–Stokes continuity equations for the fluid motions and the Poisson equation for the gravity. It extends previous approaches, first by including gravity and second by considering the PDF as a dynamical system, not a stationary one. We derive the transport equations of the density PDF, characterize its evolution, and determine the density threshold above which gravity strongly affects and eventually dominates the dynamics of turbulence. We demonstrate the occurrence of t
wo power-law tails in the PDF, with two characteristic exponents, corresponding to two different stages in the balance between turbulence and gravity. Another important result of this study is to provide a procedure to relate the observed column density PDFs to the corresponding volume density PDFs. This allows us to infer, from the observation of column densities, various physical parameters characterizing molecular clouds, notably the virial parameter. Furthermore, the theory offers the possibility to date the clouds in units of t
coll, the time since a statistically significant fraction of the cloud started to collapse. The theoretical results and diagnostics reproduce very well numerical simulations and observations of star-forming clouds. The theory provides a sound theoretical foundation and quantitative diagnostics to analyze observations or numerical simulations of star-forming regions and to characterize the evolution of the density PDF in various regions of molecular clouds.
MeV Gamma Rays from Fission: A Distinct Signature of Actinide Production in Neutron Star Mergers
Authors: Wang 王夕露) Xilu ,   (N3AS Collaboration), Vassh Nicole ,   (FIRE Collaboration), Sprouse Trevor , Mumpower Matthew , Vogt Ramona , Randrup Jorgen , Surman Rebecca 
Published: October 2020

Abstract
Neutron star mergers (NSMs) are the first verified sites of rapid neutron capture (r-process) nucleosynthesis, and could emit gamma rays from the radioactive isotopes synthesized in the neutron-rich ejecta. These MeV gamma rays may provide a unique and direct probe of the NSM environment as well as insight into the nature of the r process, just as observed gammas from the 56Ni radioactive decay chain provide a window into supernova nucleosynthesis. In this work, we include the photons from fission processes for the first time in estimates of the MeV gamma-ray signal expected from an NSM event. We consider NSM ejecta compositions with a range of neutron richness and find a dramatic difference in the predicted signal depending on whether or not fissioning nuclei are produced. The difference is most striking at photon energies above ∼3.5 MeV and at a relatively late time, several days after the merger event, when the ejecta is optically thin. We estimate that a Galactic NSM could be detectable by a next generation gamma-ray detector such as AMEGO in the MeV range, up to ∼104 days after the merger, if fissioning nuclei are robustly produced in the event.
Discovery of a Fast-expanding Shell in the Inside-out Born-again Planetary Nebula HuBi 1 through High-dispersion Integral Field Spectroscopy
Authors: Rechy-García J. S. , Guerrero M. A. , Santamaría E. , Gómez-González V. M. A. , Ramos-Larios G. , Toalá J. A. , Cazzoli S. , Sabin L. , Miranda L. F. , Fang X. , Liu J. 
Published: October 2020

Abstract
HuBi 1 has been proposed to be member of the rare class of born-again planetary nebulae (PNe), i.e., its central star experienced a very late thermal pulse and ejected highly processed material at high speeds inside the old hydrogen-rich PN. In this Letter we present GTC MEGARA integral field spectroscopic observations of the innermost regions of HuBi 1 at high spectral resolution ≃16 km s−1 and multi-epoch subarcsecond images obtained ≃12 yr apart. The analysis of these data indicates that the inner regions of HuBi 1 were ejected ≃200 yr ago and expand at velocities ≃300 km s−1, in excellent agreement with the born-again scenario. The unprecedented tomographic capabilities of the GTC MEGARA high-dispersion observations used here reveal that the ejecta in HuBi 1 has a shell-like structure, in contrast to the disrupted disk and jet morphology of the ejecta in other born-again PNe.
GW190521: Orbital Eccentricity and Signatures of Dynamical Formation in a Binary Black Hole Merger Signal
Authors: Romero-Shaw Isobel , Lasky Paul D. , Thrane Eric , Bustillo Juan Calderón 
Published: October 2020

Abstract
Pair-instability supernovae are thought to restrict the formation of black holes in the mass range

∼
50
–
135

M

⊙

. However, black holes with masses within this “high mass gap” are expected to form as the remnants of binary black hole mergers. These remnants can merge again dynamically in densely populated environments such as globular clusters. The hypothesis that the binary black hole merger GW190521 formed dynamically is supported by its high mass. Orbital eccentricity can also be a signature of dynamical formation, since a binary that merges quickly after becoming bound may not circularize before merger. In this work, we measure the orbital eccentricity of GW190521. We find that the data prefer a signal with eccentricity

e
≥
0.1

at 10 Hz to a nonprecessing, quasi-circular signal, with a log Bayes factor

ln

=
5.0

. When compared to precessing, quasi-circular analyses, the data prefer a nonprecessing,

e
≥
0.1

signal, with log Bayes factors

ln

≈
2

. Using injection studies, we find that a nonspinning, moderately eccentric (e = 0.13) GW190521-like binary can be mistaken for a quasi-circular, precessing binary. Conversely, a quasi-circular binary with spin-induced precession may be mistaken for an eccentric binary. We therefore cannot confidently determine whether GW190521 was precessing or eccentric. Nevertheless, since both of these properties support the dynamical formation hypothesis, our findings support the hypothesis that GW190521 formed dynamically.
Preliminary Target Selection for the DESI Milky Way Survey (MWS)
Authors: Prieto Carlos Allende , Cooper Andrew P. , Dey Arjun , Gänsicke Boris T. , Koposov Sergey E. , Li Ting , Manser Christopher , Nidever David L. , Rockosi Constance , Wang Mei-Yu , Aguado David S. , Blum Robert , Brooks David , Eisenstein Daniel J. , Duan Yutong , Eftekharzadeh Sarah , Gaztañaga Enrique , Kehoe Robert , Landriau Martin , Lee Chien-Hsiu , Levi Michael E. , Meisner Aaron M. , Myers Adam D. , Najita Joan , Olsen Knut , Palanque-Delabrouille Nathalie , Poppett Claire , Prada Francisco , Schlegel David J. , Schubnell Michael , Tarlé Gregory , Valluri Monica , Wechsler Risa H. , Yèche Christophe 
Published: October 2020

Abstract
The DESI Milky Way Survey (MWS) will observe ≥8 million stars between 16 < r < 19 mag, supplemented by observations of brighter targets under poor observing conditions. The survey will permit an accurate determination of stellar kinematics and population gradients, characterize diffuse substructure in the thick disk and stellar halo, enable the discovery of extremely metal-poor stars and other rare stellar types, and improve constraints on the Galaxy’s 3D dark matter distribution from halo star kinematics. MWS will also enable a detailed characterization of the stellar populations within 100 pc of the Sun, including a complete census of white dwarfs. The target catalog from the preliminary selection described here is public (Available at https://data.desi.lbl.gov/public/ets/target/catalogs/ and detailed at https://desidatamodel.readthedocs.io).
Corona Pandemic, Food Security, and Agricultural Research
Authors: Ginigaddara G.A.S. 
Published: October 2020

The current global health crisis has disrupted the whole world creating inter-related challenges of hunger, malnutrition, and food insecurity. Food systems all over the world are under huge stress. The supply chains have been disrupted, consumers are facing problems of accessing even basic food items and paying higher prices for some foods. Sri Lanka took early actions to limit the COVID-19 imposing curfew from time to time for nearly over two months. The majority of people were under home hostage. Schools and universities were closed. Those who are working in various professions stopped reporting to offices physically and started working from home. However, similar to many other countries, Sri Lanka wanted agriculture safely running as an essential business in the country to continue the food supply for markets and consumers. Though freedom was fully granted for the farmers to engage in their agricultural production activities irrespective of lockdown condition imposed in the country, farmers started to face various other problems for receiving agricultural inputs, fulfilling harvesting activities and postharvest preparations, transporting harvests to markets and even finding the right market for the products. Labour shortage mainly due to movement restrictions, social distancing rules, and illness started to impact producers, processors, traders, and others in supply chains. Farmers lost their regular markets and worried about harvesting their current crop and planting for the next season. Export bans and import restrictions created problems of reaching people the needed food items and paying unnecessarily for certain food items (e.g. turmeric powder). At the same time, loss of income and remittances limited people’s purchasing ability. People who carried out small businesses earned daily wages and served in contract basis jobs in certain firms and small-scale entrepreneurs were in more economical crisis and facing serious problems of securing their families with sustainable food supply and consumption.
Detection of muscle metastases on 18F-fluorodeoxyglucose positron emission tomography/computed tomography scan in 13 cases
Authors: Doudouh Abderrahim , Oueriagli Salah , Bakkali Jaafar 
Published: October 2020

AbstractMuscular metastases (MMs) form an infrequent entity, and their physiopathology is still not well-defined. In this study, we estimated the incidence of MMs that were detected by 18F-fluorodeoxyglucose positron emission tomography/computed tomography and also specified their metabolic characteristics. This study includes 13 patients with MMs from a remotely located primary tumor. The results of this study showed an incidence of MMs at about 1%, with the most frequently involved muscles being iliopsoas and paraspinal. Lung cancer seems to be the most common tumor that causes MMs. Furthermore, these MMs vary in size and physiological uptake; they seem to be out of the ordinary and easily detected. They are often associated with other extra muscular locations and frequently involve the trunk muscles. Their detection in the course of the evolution of a specific neoplasia testifies to their aggressiveness and portends an unfavorable prognosis. The data in our series confirm that in the literature regarding the underlying primary tumors and anatomical sites involved by MMs.
“AMPE” Exercise Programme Has Positive Effects on Anthropometric and Physiological Parameters of School Children: A Pilot Study
Authors: MOSES M. Omoniyi1  , AFIFA Daniel  , ASAMOAH M. Anthony  , SARPONG Priscilla  , SARPONG Emmanuel  , APPIAH P. Opoku  , AKOTO Francisca  
Published: October 2020

BACKGROUND: Projection of the effectiveness of house-hold physical activity may be a vital tool to improve active lifestyle. Although ampe is a common house-hold recreational physical activity among all population groups especially school children in Ghana, no empirical evidence of its effects on the anthropometric and physiological parameters of the children. This pilot study examined the effect of ampe exercise programme on the anthropometric and physiological parameters of school children.METHODS: Purposive and stratified sampling techniques were applied to recruit 78 school children (ages of 9 to 12, mean age of 10.65±0.94 years). The participants attended 40 minutes of ampe exercise program three times per week, for four weeks consecutively. Body mass index, waist circumference, hip circumference, waist-to-hip ratio; % body fat, diastolic blood pressure, systolic blood pressure and heart rate were measured prepost training.RESULTS: Ampe exercise programme produced positive effects on all parameters. Body weight (0.31%) and body mass index (0.58%) decreased significantly (P<0.05). Systolic blood pressure (3.15%), diastolic blood pressure (1.92%) and heart rate (2.13) significantly improved (P<0.05).
CONCLUSION: Ampe exercise programme is effective as paediatric obesity house-hold intervention to provide the impetus for active lifestyles of school children.
Enhancing Workplace Safety Culture in the Mining Industry in Ghana
Authors: Opoku Felix Kwame , Kosi Isaac , Degraft-Arthur Dominic 
Published: October 2020

The paper concerns organisational safety culture and how it may be applied to reduce employee accidents in the mining industry in Ghana. A sample of 340 managerial workers of three mining companies in the Tarkwa Nsuaem Municipality was selected using the simple random sampling technique. Data for the study was gathered using a survey questionnaire. The Structural Equation Modelling analysis technique was performed to establish the relationship between safety culture and each of the five dimensions of workplace safety (work safety, management safety practices, safety programmes, supervisor safety and co-worker safety). It was found that safety culture is a significant positive predictor of work safety (R2 = 0.039), management safety practices (R2 = 0.272), safety programmes (R2 = 0.159), co-worker safety (R2 = 0.225) and supervisor safety (R2 = 0.199). The study concluded that workplace safety can be improved by enhancing the safety culture in the mining industry in Ghana. The study recommends that in order to curb the incidence and occurrence of accidents and injuries in the mining industry in Ghana, Human Resource (HR) managers should lay more emphasis on ways that would enhance the safety culture of all employees in the industry.
Keywords: Safety Culture, Mining Industry, Workplace Safety, Industrial Accidents, Ghana
An Assessment of Socio-economic Characteristics of Slum Residents in Ilorin, Nigeria
Authors: Mas’ud O.T. , Olawepo R.A. , Ajiboye J.K. 
Published: October 2020

This study examines the significance of socio-economic characteristics in making housing quality good for human living. It also examines the influence of socio-economic on the health behaviour and efficiency of man and the nation as a whole. The study was carried out with the aid of questionnaire administration, building and facility survey using purposeful sampling techniques. A total of 20 buildings in each of the fifteen identified slums were picked for questionnaire administration. Also, data were collected from related Ministries and Commission. The descriptive analysis was used to determine the vulnerability of the study area to slum condition and also to identify the extent of the decay. The descriptive analysis revealed that, the study area exhibits slum condition that has impact on socio-economic, life style and health of the residents, as well as general outlook of the environment. ANOVA was used to test whether or not there are variations in socio-economic, housing and environmental quality in all the locations. ANOVA reveals that there are significant variations in socio-economic, housing and environmental qualities among locations in the study area. Recommendations were made to guide the policy makers towards enhancing the lives of the residents of the areas, by making education affordable, public enlightenment and also to enhance the living standard of the residents by establishing industries
Keyword: socio-economic characteristics, slums, housing quality, life style