bluuebunny/crossref_metadata_2025_split huggingface dataset:
Helium-rich Superluminous Supernovae from the Zwicky Transient Facility
Authors: Yan Lin , Perley D. A. , Schulze S. , Lunnan R. , Sollerman J. , De K. , Chen Z. H. , Fremling C. , Gal-Yam A. , Taggart K. , Chen T.-W. , Andreoni I. , Bellm E. C. , Cunningham V. , Dekany R. , Duev D. A. , Fransson C. , Laher R. R. , Hankins M. , Ho A. Y. Q. , Jencson J. E. , Kaye S. , Kulkarni S. R. , Kasliwal M. M. , Golkhou V. Z. , Graham M. , Masci F. J. , Miller A. A. , Neill J. D. , Ofek E. , Porter M. , Mróz P. , Reiley D. , Riddle R. , Rigault M. , Rusholme B. , Shupe D. L. , Soumagnac M. T. , Smith R. , Tartaglia L. , Yao Y. , Yaron O. 
Published: October 2020

Abstract
Helium is expected to be present in the massive ejecta of some hydrogen-poor superluminous supernovae (SLSN-I). However, until now only one event has been identified with He features in its photospheric spectra (PTF10hgi). We present the discovery of a new He-rich SLSN-I, ZTF19aawfbtg (SN2019hge), at z = 0.0866. This event has more than 10 optical spectra at phases from −41 to +103 days relative to the peak, most of which match well with that of PTF10hgi. Confirmation comes from a near-IR spectrum taken at +34 days, revealing He i features with P-Cygni profiles at 1.083 and 2.058 μm. Using the optical spectra of PTF10hgi and SN2019hge as templates, we examined 70 other SLSNe-I discovered by Zwicky Transient Facility in the first two years of operation and found five additional SLSNe-I with distinct He-features. The excitation of He i atoms in normal core-collapse supernovae requires nonthermal radiation, as proposed by previous studies. These He-rich events cannot be explained by the traditional 56Ni mixing model because of their blue spectra, high peak luminosities, and long rise timescales. Magnetar models offer a possible solution since pulsar winds naturally generate high-energy particles, potential sources of nonthermal excitation. An alternative model is the interaction between the ejecta and dense H-poor circumstellar material, which may be supported by observed undulations in the light curves. These six SLSNe-Ib have relatively low-peak luminosities (rest frame M

g
= −20.06 ± 0.16).
Direct Imaging Discovery of a Young Brown Dwarf Companion to an A2V Star
Authors: Wagner Kevin , Apai Dániel , Kasper Markus , McClure Melissa , Robberto Massimo , Currie Thayne 
Published: October 2020

Abstract
We present the discovery and spectroscopy of HIP 75056Ab, a companion directly imaged at a very small separation of 0.″125 to an A2V star in the Scorpius–Centaurus OB2 association. Our observations utilized Very Large Telescope/Spectro-Polarimetric High-contrast Exoplanet Research Experiment between 2015 and 2019, enabling low-resolution spectroscopy (0.95–1.65 μm), dual-band imaging (2.1–2.25 μm), and relative astrometry over a four-year baseline. HIP 75056Ab is consistent with spectral types in the range of M6−L2 and T
eff ∼ 2000–2600 K. A comparison of the companion’s brightness to evolutionary tracks suggests a mass of ∼20–30 M
Jup. The astrometric measurements are consistent with an orbital semimajor axis of ∼15–45 au and an inclination close to face-on (i ≲ 35°). In this range of mass and orbital separation, HIP 75056Ab is likely at the low-mass end of the distribution of companions formed via disk instability, although a formation of the companion via core accretion cannot be excluded. The orbital constraints are consistent with the modest eccentricity values predicted by disk instability, a scenario that can be confirmed by further astrometric monitoring. HIP 75056Ab may be utilized as a low-mass atmospheric comparison to older, higher-mass brown dwarfs, and also to young giant planets. Finally, the detection of HIP 75056Ab at 0.″125 represents a milestone in detecting low-mass companions at separations corresponding to the habitable zones of nearby Sun-like stars.
Distribution and area of low voltage and dense scar zones and their relation to left atrial enlargement in ablation-naïve patients with paroxysmal atrial fibrillation
Authors: Shalganov Tchavdar , Stoyanov Milko , Mirazchiyski Metodi , Kunev Boyan 
Published: October 2020

There is paucity of studies correlating the left atrial (LA) dilation and the LA total and abnormal voltage areas in patients with atrial ﬁ brillation (AF). We sought to determine the area of LA and its segments by high-density mapping in patients with paroxysmal AF, and to correlate the LA dilation deﬁ ned by echocardiography with the total and the abnormal LA areas. Material and Methods. Retrospective study of patients with paroxysmal AF and pulmonary vein isolation proceeded by high-density mapping in sinus rhythm. All had transthoracic echocardiography and LA dilation, if present, was graded as mild/moderate-severe. LA voltage was deﬁ ned as low (< 0.5 mV) or scar (< 0.1 mV). The LA was divided in 5 segments and the total and segmental area, low voltage area and scar area were measured. Data were presented as mean ± SD or median and interquartile interval (25-75%) depending on normality of distribution. Shapiro-Wilk test, Spearman T correlation, Kruskal-Wallis, and ANOVA analysis were used. A p-value < 0.05 was considered significant. Results. Sixty-seven patients (66% males) were studied. LA enlargement was present in 58% (mild enlargement in 39%, moderate/severe in 19%). Low voltage and scar areas were found in both groups with and without LA dilation. Moderate correlation was found between the percentage of abnormal area and the degree of LA dilation (none vs mild vs moderate/severe), rho = 0.44, p = 0.0002. In patients with non-dilated LA the mean total LA area was 100.4 ± 17 cm2 and the abnormal area was < 10% (9.9%, 6.2-14.8%), with barely detectable scar. In patients with LA enlargement the total area was approximately 10% larger (109.8 cm2, 100.9-123.8 cm2), however the abnormal area was almost doubled (17.1%, 11.1-26.8%), and there were small yet measurable dense scar areas. Conclusions. Low voltage LA areas < 0.5 mV were found universally by high-density mapping in patients with paroxysmal AF, irrespective of the presence of LA enlargement. However, only patients with LA enlargement had measurable scar areas. The total abnormal area correlated moderately with the degree of LA dilation deﬁ ned by echocardiography.
FAIR Digital Objects and Natural Science Collection Data
Authors: Islam Sharif 
Published: October 2020

The Distributed System of Scientific Collections (DiSSCo) is a new Research Infrastructure that is working towards the unification of all European natural science collections under common curation, access policies, and practices (Addink et al. 2019). The physical specimens in the collections and the vast amount of data derived from and linked to these specimens are important building blocks for this unification process. Primarily coming from large scale digitization projects (Blagoderov et al. 2012) along with new types of data collection, curation, and sharing methods (e.g. Kays et al. 2020), these specimens hold data that are critical for different scientific endeavours (Cook et al. 2020, Hedrick et al. 2020). Therefore it is important that the data infrastructure and the relevant services can provide a long-term sustainable and reliable access to these data. To that end, DiSSCo is working towards transforming a fragmented landscape of the natural science collections into an integrated data infrastructure that can ensure that these data can be easily Findable, more Accessible, Interoperable and Reusable – in other words, comply with the FAIR Guiding Principles (Wilkinson et al. 2016).
A key decision for the design of this FAIR data infrastructure was to adopt FAIR Digital Objects (Wittenburg and Strawn 2019) that will enable the creation of Digital Specimen—a machine-actionable digital twin of the physical specimen (Lannom et al. 2020). This FAIR Digital Object by design, ensures FAIRness of the data (De Smedt et al. 2020) and thus will allow DiSSCo to provide services that are essential for natural science collection-based research. This talk summarises the motivation behind this adoption by showing how design decisions and best practices were influenced by the FAIR data principles, global discussions around FAIR Digital Objects and outputs from the Research Data Alliance (RDA) interest and working groups.
Impact of COVID-19 on People Suffering with Epilepsy
Authors: Sureka Rajendra K. , Gaur Vikas , Gupta Medha 
Published: October 2020

Background:
Epilepsy is one of the most common problems in neurology clinical practice and currently we are in the midst of the coronavirus outbreak. The coronavirus pandemic is an epidemiological and psychological crisis, which is likely to affect persons with epilepsy.

Objectives:
This study was designed to evaluate the impact of COVID-19 pandemic on patients with epilepsy and effects on their mental health.

Materials and Methods:
This was a cross-sectional web-based survey carried out at the department of Neurology at a tertiary care hospital. A questionnaire was designed in the local language using Google Forms to assess basic knowledge regarding epilepsy, coronavirus, effects of COVID-19 and lockdown on epileptic patients and also effects on their mental health. The link to the online survey was distributed via WhatsApp messenger to epilepsy patients.

Results:
One hundred fifty-six cases were enrolled with 69.1% were below 34 years of age and male: female ratio was 1.2:1. Only 34.3% of the participants were employed and 50% of patients had an income of less than Rs. 3000 per month. Of the patients enrolled, 20.5% reported the “devil” and superstitions as a cause of epilepsy and only 10% of patients thought that tantric (holy priest) could treat the disease better than doctors. 53.8% of patients worried about getting COVID-19 and could not stop thoughts about being infected by coronavirus bothering them. 30.3% patients had increased seizure frequency during COVID-19 pandemic, of which the most common reason was that they forgot to take regular antiepileptic drugs (22.7%) or they had faced difficulty in obtaining medicine due to lockdown (12.1%). During the pandemic, 17% of patients reported depression symptoms and another 21% reported anxiety symptoms.

Conclusion:
The current COVID-19 pandemic negatively affected patients with epilepsy and increased seizure frequency, depression, anxiety, unemployment, and financial difficulty in obtaining medication.
Horizontal Mobility of Heavy Metals from Dumpsite in North Central States, Nigeria
Authors: Bala J.D. , Musa J.J. , Mustapha H.I. , Yerima I.Y. , Sunday D.E. , Musa A.P. 
Published: October 2020

Industrialization and population growth has lead to the introduction of toxic substances into the environment as waste from manufacturing processes. This study describes the horizontal mobility of this waste containing heavy metals from dump sites to the surrounding environment of North Central state, Nigeria. Soil samples were collected within the dumpsites and the immediate surrounding soil at distance of 10m and 20m away to assess the migration and potential bioavailability of Cr, Fe, Mn, Pb, Zn, Cu and Al. Total concentration of the heavy metals and their fractionation were determined. The results indicate that heavy metals are more concentrated in the uppermost layer with significant migration down the slope, thereby posing a threat to groundwater quality. In the fractions, the concentrations of the metals follow this sequence: Mn>Fe>Cu>Zn>Cr>Al. The mobility factors of the heavy metals are significantly high indicating high potential mobility and bioavailable forms of these heavy metals. The high concentrations of the heavy metals particularly Cr, as observed in the study is as a result of anthropogenic activities on enrichment of natural soil with bioavailable heavy metals. Consequently, there is a need to be cautious in the way waste that is generated from heavy metals sources is added to natural soil.
Key words: Dump site; Environment; Heavy metals; Soil; Waste
Toxicological studies of silver nanoparticles synthesized from Calopogonium mucunoides aqueous leaf extract on Wistar rats
Authors: Adedeji A.S. , Kuta F.A. , Tijani J.O. , Adabara N.U. 
Published: October 2020

Increasing usage of nanosilver (AgNPs) for biomedical purposes outstrips the handiness of safety evaluation studies. This study investigates oral toxicity of biogenic AgNPs (at 50, 75, 100 and 150 μg/kg) on rats. Results analysis revealed that C. mucunoides AgNPs improved dietary intake and body weight of rats. Level of serum total protein significantly increased 9.54±0.05, 8.31±0.06, 11.31±0.41, 10.48±0.65 g/dL compared to control 6.43±0.55 g/dL while serum AST significantly reduced to 0.05±0.00 and 0.10±0.02U/L at 50 and 75 μg/mL. AgNPs did not significantly (P ˃ 0.05) altered serum chloride, urea, ALT and creatinine relative to the control. However, serum potassium (10.74±1.86 mmol/l) significantly decreased (P < 0.05) to 3.11±0.71, 3.12±2.50 4.64±1.47, 5.79±1.30mmol/L respectively. There was also a significant (P < 0.05) dose dependent upsurge in platelets (618.50±48.79, 743.50±17.68, 763.50±10.60 and 843.50±24.75) and MCV (49.50±0.71, 52.50±0.71, 53.50±0.71 and 56.00±4.24) compared to the control (617.50±79.90 and 43.00±0.00) respectively. The haemoglobin, PCV, MCHC, MCH, RBC, WBC, lymphocytes, monocytes, eosinophils and basophils values were not different (P ˃ 0.05) from the control. Results obtained suggest that AgNPs is relatively safe, although it altered serum total protein and potassium concentrations, no rat died due toxicological effect.
Keywords: Alterations, nanosilver, toxicity, upsurge.
Alternative method of reducing sugars determination in some selected fizzy drinks and fruits by chromic acid reagent
Authors: Olajide Mustapha A. 
Published: October 2020

Chromic acid reagent as an alternative colorimetric method for the quantitative determination of reducing sugars and ascorbic acid in some selected fizzy drinks: Seven Up, Limca, Mirinda, Cocoa-Cola, Fanta, Pepsi Cola, Maltina, Guinness Malt, Hi-Malt and Maltonic) and fruits: pineapple (Ananas cosmoses), sweet orange (Cimifi sinensis), grape fruit (Dints paradise) and tangerine (Citrus reticulate) has been studied. Chromic method involves sugar solution of about 1% concentration. treated with an equal volume of concentrated nitric acid and a few drops of a 5% solution of potassium dichromate was added, a blue colour develops in less than a minute in the cold and the absorbance taken in a Spectronic 20D Spectrophotometer at 560 um. Results obtained from the simple chromic acid as test method compares well with those obtained from the titrimetric methods of Association of Official Analytical Chemists (AOAC, 2012) and Pearson (1991) as control, with negligible variations. Apart from being a very powerful oxidizing agent, its reaction with monosaccharide, disaccharides and ascorbic acid are less-time consuming, showed distinct colour development and its easy preparation, made chromic acid reagent a faster, better and suitable alternative method for the quantitative determination of reducing sugars and ascorbic acid in routine analyses of foods.
Keywords: reducing sugar, ascorbic acid, chromic reagent.
Software defect prediction: A multi-criteria decision-making approach
Authors: Balogun A.O. , Bajeh A.O. , Mojeed H.A. , Akintola A.G. 
Published: October 2020

Failure of software systems as a result of software testing is very much rampant as modern software systems are large and complex. Software testing which is an integral part of the software development life cycle (SDLC), consumes both human and capital resources. As such, software defect prediction (SDP) mechanisms are deployed to strengthen the software testing phase in SDLC by predicting defect prone modules or components in software systems. Machine learning models are used for developing the SDP models with great successes achieved. Moreover, some studies have highlighted that a combination of machine learning models as a form of an ensemble is better than single SDP models in terms of prediction accuracy. However, the efficiency of machine learning models can change with diverse predictive evaluation metrics. Thus, more studies are needed to establish the effectiveness of ensemble SDP models over single SDP models. This study proposes the deployment of Multi-Criteria Decision Method (MCDM) techniques to rank machine learning models. Analytic Network Process (ANP) and Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) which are types of MCDM techniques are deployed on 9 machine learning models with 11 performance evaluation metrics and 11 software defects datasets. The experimental results showed that ensemble SDP models are best appropriate SDP models as Boosted SMO and Boosted PART ranked highest for each of the MCDM techniques. Besides, the experimental results also validated the stand of not considering accuracy as the only performance evaluation metrics for SDP models. Conclusively, more performance metrics other than predictive accuracy should be considered when ranking and evaluating machine learning models.
Keywords: Ensemble; Multi-Criteria Decision Method; Software Defect Prediction
Oaxaca - blinder decomposition extended for the non-linear model to identify the ownership gap in the exit rate
Authors: Ha Nguyen Minh 
Published: October 2020

The purpose of this research is to identify factors to explain the gap in exit rate between state and non-state firms in Vietnam. With a sample of 7,962 Vietnamese firms and using the Oaxaca-Blinder decomposition extended for non-linear models, the research finds out that a very large part of the ownership gap in exit rate between state and nonstate firms cannot be explained by the included covariates, but it is almost explained by
the effects of differences in the coefficients of covariates. In particular, the differences in coefficients of covariates of initial assets, the industrial sector (mining, construction and manufacturing industries), and the service sector considerably increase the ownership gap in exit rate, but the difference in the coefficient of initial employment reduces the ownership gap in the exit rate. Moreover, differences in explanatory variables between state and non-state firms explain a very small part of the ownership gap in exit rate. This
means that an estimate of the reduction in state and non-state firms’ exit rates (resulting from giving non-state firms the same characteristics as state firms) is very small. The differences in coefficients have a much greater impact on differences in exit rates than characteristics that may be due to existing discrimination between state and non-state firms.
Entrepreneurship and economic development: A literature review
Authors: Phuc Nguyen Van 
Published: October 2020

This paper makes a comprehensive review of entrepreneurship on economic development in economic theory. It indicates how entrepreneurship is crucial for economic development. The role of entrepreneurship on economic development originated from different understandings on the nature of economic system. It is argued that the role of the entrepreneur has been moved out of the neoclassical model because a crucial assumption of the model is that decision-making merely involves marginalist calculation to optimise production, based upon public information supplied by the price system. The explanation for the phenomenon of economic development depends on how we understand the nature of the market process. In this respect, the economics of entrepreneurship is different from mainstream economics. For mainstream economics, the market is generally characterised by equilibrium. For the economics of entrepreneurship, the market process is characterised by disequilibrium. The review of literature indicates that entrepreneurship has different essential features that all are critical to economic development
and the market process. They are Kirzner’s arbitragers or Schumpeter’s innovators. They are Knight’s uncertainty-bearing people. They assume managerial or leadership roles and thus function as the main allocators of scarce resources in the economic system as identified by Baumol and Casson. Entrepreneurship is a solution to X-inefficiency, by motivating efforts within firms as argued by Leibenstein. All this has important implications for economic development. Millions of business decisions made by numerous entrepreneurs daily affect an economy a great deal. The pace of economic development ultimately depends on such endeavour
of numerous entrepreneurs. It is normally believed that the lagging behind of many developing countries lies in their lack of entrepreneurship. The policy implication is that, in order to have good economic development, governments should create a favourable environment for entrepreneurs to carry out above-mentioned functions in the economy.
Título en español.
Authors: H. D. Dubey  , Rita L. Rodríguez  
Published: October 2020

Durante 18 meses se estudiaron, en condiciones de laboratorio, los cambios producidos en los microorganismos presentes en el suelo arcilloso ácido laterítico Humatas y en el alcalino y fértil San Antón lómico, ambos incubados a 23° ± 1° C. después de haber recibido aplicaciones de 2,4- dicloro-(o-cloroaniline)-s-triazina (Dyrene) y etileno bisditiocarbamato de manganeso (Maneb) en concentraciones de 0, 60, 240 y 960 p.p.m. En general, el número de bacterias aumentó y el de actinomicetos y hongos disminuyó, especialmente a las concentraciones más altas de los agentes químicos. El aumento en el número de bacterias cesó a los 10 meses, excepto en el caso del Maneb a 960 p.pm., cuando el incremento persistió por más tiempo. Parecen ser las bacterias los principales microorganismos responsables de la degradación de estos fungicidas en el suelo. El Maneb produjo cambios cuantitativos y cualitativos en la población de hongos. En cuanto a la reacción al tratamiento químico, se notaron diferencias entre los microorganismos de uno y otro suelo. La inoculación con suelo fresco neutralizó la inhibición de los microorganismos.
Título en español.
Authors: J. Coward-Lord  , J. A. Arroyo-Aguilú  , O. García-Molinari  
Published: October 2020

Se evaluaron muestras de las siguientes 10 yerbas forrajeras tropicales: Pangola, Digitaria decumbens; Congo, Brachiaria ruziziensis; Buffel, Cenchrus ciliaris; Guinea, Panicum maximum,' Jaragua, Hyparrhenia rufa; Pangola Gigante, Digitaria valida; "African Crab", Digitaria swazilandensis; Elefante Venezolana, Pennisetum setosum y Limpo, Hemarthria altissima, de 30 a 180 días de edad, tomadas a intervalos de corte de 30 días comenzando el 20 de agosto de 1970. Las yerbas se encontraban ya establecidas en parcelas con un área de 10 m2 en la colección de gramíneas del Colegio de Ciencias Agrícolas de la Universidad de Puerto Rico, localizada en Mayagüez. Se abonaron ligeramente con NH4NO3 a razón de 350 kg./ha. Se determinó el contenido de materia seca total (TDM). Se efectuaron determinaciones químico-analíticas de la proteína cruda (N X 6.25) (CP), la fibra cruda (CF), el extracto etéreo (EE) y la ceniza (A). El extracto libre de nitrógeno (NFE) se determinó como la diferencia entre 100 y la suma de la CP, la CF, el EE y la A. Los resultados se analizaron estadísticamente por el método de varianza. Se encontraron diferencias altamente significativas en todos los componentes con respecto a las especies forrajeras y a las edades de corte. Según fueron madurando las yerbas disminuyeron la CP, el EE y la A, mientras que la TDM, la CF y el NFE aumentaron con diferencias altamente significativas. El mayor cambio en valor nutritivo tuvo lugar entre los 30 y los 60 días de edad.