bluuebunny/crossref_metadata_2025_split huggingface dataset:
How Struve and Tenner Started the Work of Their Life
Authors: Viik T. , Randjärv J. 
Published: March 2017

Abstract
The great Russian-Scandinavian arc measurement was initiated by two men: F. G. W. Struve and C. F. Tenner. When they decided to join their endeavours, they both had obtained a substantial experience - Struve had completed the Livonia triangulation and he had measured the meridian arc from Jekabpils to Hogland, and Tenner had finished the triangulation for the Vilnius government and was continuing it for Kurland, Grodno and Minsk governments. In 1827 Tenner came forward with the idea to join their arcs, and during the meeting of both men in Tartu in 1828 they signed the respective agreement. The most difficult point in merging the projects was the use of measuring rods with different units of length: Struve used European toises and Tenner Russian sazhens. These rods had to be thoroughly compared, which they did and the results were checked independently by F. F. Schubert and F. W. Bessel who found them to be in a very good accordance. The later extension of the meridian arc northward to Fuglenes and to Stara-Nekrasivka in south allowed Struve to determine the preliminary result for the oblateness of the Earth with a great precision (α = 1:294.73).
Anders Celsius’ Contributions to Meridian Arc Measurements and the Establishment of an Astronomical Observatory in Uppsala
Authors: Stempels H. C. 
Published: March 2017

Abstract
Astronomy has been on the curriculum of Uppsala University from at least the middle of the 15th century. However, since Uppsala also was the ecclesiastical centre of Sweden, the acceptance of new ideas, such as the Copernican heliocentric system, was slow. At the same time, more peripheral universities in the Swedish empire, including Dorpat/Tartu, enjoyed a larger freedom. It was not until the early 18th century that a ‘modern’ astronomy emerged in Uppsala. This effort was to a large extent led by Anders Celsius (1701-1744), who was able to establish good international contacts with astronomers in continental Europe. Celsius participated in De Maupertuis’ expedition to the far north of Sweden, in order to measure the meridian arc and determine the shape of the Earth. This paper explores how Celsius became involved in De Maupertuis’ expedition, and how this effort paved the way to the establishment of a fully equipped astronomical observatory, including an extensive collection of books and instruments, most of which survives up to this day.
Bernhard Schmidt and the Schmidt Telescope for Mapping the Sky
Authors: Wolfschmidt G. 
Published: March 2017

Abstract
Bernhard Voldemar Schmidt (1879-1935) was born in Estonia. He ran an optical workshop in Mittweida, Saxonia, between 1901 and 1927. Astronomers appreciated the quality of his telescopes. Starting in 1925, working freelance in Hamburg Observatory, he developed a short focal length optical system with a large field of view. He succeeded in inventing the “Schmidt Telescope” in 1930, which allows the imaging a large field of the sky without any distortions. Shortly after Schmidt’s death, the director of the observatory published details on the invention and production of the Schmidt Telescope. After World War II, Schmidt telescopes have been widely used. The first large Schmidt telescope was built in 1948, the “Big Schmidt” (126 cm), Mount Palomar, USA. Schmidt telescopes are also important tools for cosmology. The result of the Palomar Observatory Sky Surveys (1949-1958, 1985-1999) is a data base of about 20 million galaxies and over 100 million stars, supplemented in 1971 by the ESO Schmidt for the southern sky. Also high resolution spectrometers can be fitted to the Schmidt telescope. The 80 cm Schmidt telescope of Hamburg Observatory, planned since 1936, finished 1955, is on Calar Alto, Spain, since 1975. Combined with two objective prisms, it was used for a Quasar survey project.
Astrometry Lost and Regained
Authors: Høg E. 
Published: March 2017

Abstract
Technological and scientific developments during the past century made a new branch of astronomy flourish, i.e. astrophysics, and resulted in our present deep understanding of the whole Universe. But this brought astrometry almost to extinction because it was considered to be dull and old-fashioned, especially by young astronomers. Astrometry is the much older branch of astronomy, in fact 2000 years of age, which performs accurate measurements of positions, motions and distances of stars and other celestial bodies. Astrometric data are of great scientific and practical importance for investigation of celestial phenomena and also for control of telescopes and satellites and for monitoring of Earth rotation. Our main subject is the development during the 20th century which finally made astrometry flourish as an integral part of astronomy through the success of the Hipparcos astrometric satellite, soon to be followed by the even more powerful Gaia mission.
Measuring the Cosmic Web
Authors: Müller Volker , Hoffmann Kai , Nuza Sebastián E. 
Published: March 2017

Abstract
A quantitative study of the clustering properties of the cosmic web as a function of absolute magnitude and color is presented using the SDSS Data Release 7 galaxy survey. Mark correlations are included in the analysis. We compare our results with mock galaxy samples obtained with four different semi-analytical models of galaxy formation imposed on the merger trees of the Millenium simulation. The clustering of both red and blue galaxies is studied separately.
Cosmological Neutrino Background and Connected Problems
Authors: Sapar A. 
Published: March 2017

Abstract
Applying the formulae derived by us (A. Sapar 1964) for the Universe filled with baryonic matter and decoupled particles (photons and massive neutrinos), a scenario of evolution of the Universe is studied. The dark energy can be treated as the kinetic energy excess over the potential energy of all particles in the hyperbolic Universe which is going to its new, kinetic energy dominated epoch of evolution. The dark mass can be due to slowly moving rest-mass neutrinos, crossing the galaxies where they form wide iso-potential (constant orbital velocity) shells. The real Big Bang is assumed to precede the Planck unit time and this removes necessity of the later inflation phenomenon. The possibility to modify the equations of cosmology into the non-local ones by gravitational potential of the Universe is shortly discussed.
High-Quality Fast QPOs from Magnetars: An Electric Circuit Model
Authors: Stepanov Alexander , Zaitsev Valery , Valtaoja Esko 
Published: March 2017

Abstract
An interpretation of high-frequency (20-2400 Hz) fast quasiperiodic oscillations of magnetars in terms of an equivalent electric circuit is given. Observed periods and the very high quality of quasi-periodic oscillations are explained. The oscillation source is represented as a hot electron-positron plasma in a ‘trapped fireball’, a system of current-carrying magnetic loops of various sizes. The physical parameters of a ‘trapped fireball’ in the flare of SGR 1806-20 (2004 December 27) are estimated.
Studying the Patterns of the Universe
Authors: Sepp T. , Tempel E. , Gramann M. , Nurmi P. , Haupt M. 
Published: March 2017

Abstract
The SDSS galaxy catalog is one of the best databases for galaxy distribution studies. The SDSS DR8 data is used to construct the galaxy cluster catalog. We construct the clusters from the calculated luminosity density field and identify denser regions. Around these peak regions we construct galaxy clusters. Another interesting question in cosmology is how observable galaxy structures are connected to underlying dark matter distribution. To study this we compare the SDSS DR7 galaxy group catalog with galaxy groups obtained from the semi-analytical Millennium N-Body simulation. Specifically, we compare the group richness, virial radius, maximum separation and velocity dispersion distributions and find a relatively good agreement between the mock catalog and observations. This strongly supports the idea that the dark matter distribution and galaxies in the semi-analytical models and observations are very closely linked.
A Photo-Ionization Method for Black Hole Mass Estimation in Quasars
Authors: Marziani Paola , Negrete C. Alenka , Dultzin Deborah , Sulentic Jack W. 
Published: March 2017

AbstractDetermining the masses of the central compact object believed to power all active galactic nuclei is relevant to our understanding of their evolution and of their inner workings. Keys to present-day mass estimates are: (1) the assumption of line broadening due to virial motion of the emitting gas, (2) an estimate of the distance of broad-line emitting gas from the central compact object, and (3) a measure of the AGN luminosity. We discuss the merits and the limitations of an alternative method based on estimates of physical conditions in the broad line emitting region derived from an appropriate multi-component analysis of emission line profiles. This ‘photo-ionization method’, applied to UV intermediate-ionization lines appears to be promising for at least a sizable population of high-z quasars.
AGN Dusty Tori as a Clumpy Two-Phase Medium: the 10 μm Silicate Feature
Authors: Stalevski Marko , Fritz Jacopo , Baes Maarten , Nakos Theodoros , Popović Luka Č. 
Published: March 2017

AbstractWe investigated the emission of active galactic nuclei dusty tori in the infrared domain, with a focus on the 10 μm silicate feature. We modeled the dusty torus as a clumpy two-phase medium with high-density clumps and a low-density medium filling the space between the clumps. We used a three-dimensional radiative transfer code to obtain spectral energy distributions and images of tori at different wavelengths. We calculated a grid of models for different parameters and analyzed the influence of these parameters on the shape of the mid-infrared emission. A corresponding set of clumps-only models and models with a smooth dust distribution is calculated for comparison. We found that the dust distribution, the optical depth and a random arrangement of clumps in the innermost region, all have an impact on the shape and strength of the silicate feature. The 10 μm silicate feature can be suppressed for some parameters, but models with smooth dust distribution are also able to produce a wide range of the silicate feature strength.
The Influence of Solar Spectral Lines on Electron Concentration in Terrestrial Ionosphere
Authors: Nina A. , Čadež V. , Srećković V. A. , Šulić D. 
Published: March 2017

Abstract
One of the methods of detection and analysis of solar flares is observing the time variations of certain solar spectral lines. During solar flares, a raise of electron concentration occurs in Earth’s ionosphere which results in amplitude and phase variations of the recorded very low frequency (VLF) waves. We compared the data obtained by the analysis of recorded VLF signals and line spectra for different solar flares. In this paper we treated the DHO VLF signal transmitted from Germany at the frequency of 23.4 kHz recorded by the AWESOME system in Belgrade (Serbia) during solar flares in the period between 10:40 UT and 13:00 UT on 2011 April 22.
Plasmas Generated with Gas Mixtures at the Atmospheric Pressure
Authors: Calzada M. D. , Muñoz J. , Rincón R. , Jiménez M. , Sáez M. 
Published: March 2017

Abstract
Several applications, such as metal surface nitriding, medical instrument sterilization and chemical analysis, have been developed or improved using a gas mixture as plasmogen gas. Research carried out on these subjects covers the aspect of knowing the processes that take place in plasmas which depend on the densities of the different plasma particles and their energy values. In this paper, the results obtained from the application of spectroscopic techniques for the characterization of surface wave discharges at the atmospheric pressure, generated with more than one gas type, are presented, particularly for the Ar-He, Ar-Ne and Ar-N2 plasmas.
Multiwavelength SED as a Tool in Understanding Outbursts of Symbiotic Binaries
Authors: Skopal A. 
Published: March 2017

Abstract
Symbiotic binaries consist of a few sources of radiation contributing to spectral energy distribution (SED) from hard X-rays to radio wavelengths. To identify the basic physical processes forming the observed spectrum, we have to disentangle the composite SED into its individual components of radiation, i.e., to determine their physical parameters. Spectral disentangling of different objects at different stages of activity allows us to understand the mechanism of their outbursts. In this contribution I demonstrate the method of multiwave-length modeling SEDs on the example of two classical symbiotic stars, AG Dra and Z And.
RR Tel: Determination of Dust Properties During Minimum Obscuration
Authors: Jurkić T. , Kotnik-Karuza D. 
Published: March 2017

Abstract
the ISO infrared spectra and the SAAO long-term JHKL photometry of RR Tel in the epochs during minimum obscuration are studied in order to construct a circumstellar dust model. the spectral energy distribution in the near- and the mid-IR spectral range (1–15 μm) was obtained for an epoch without the pronounced dust obscuration. the DUSTY code was used to solve the radiative transfer through the dust and to determine the circumstellar dust properties of the inner dust regions around the Mira component. Dust temperature, maximum grain size, dust density distribution, mass-loss rate, terminal wind velocity and optical depth are determined. the spectral energy distribution and the long-term JHKL photometry during an epoch of minimum obscuration show almost unattenuated stellar source and strong dust emission which cannot be explained by a single dust shell model. We propose a two-component model consisting of an optically thin circmustellar dust shell and optically thick dust outside the line of sight in some kind of a flattened geometry, which is responsible for most of the observed dust thermal emission.
News from AG Draconis
Authors: Leedjärv L. , Burmeister M. 
Published: March 2017

Abstract
AG Dra is a classical symbiotic star that undergoes major outbursts at intervals between 12-15 years. We present spectroscopic observations of four emission lines (Hα, Hβ, He II 4686 Å, Raman scattered OVI 6825 Å) before, during and after the major outburst that started in 2006. Interesting strengthenings of the emission lines took place in late 2005 and in early 2008. the latter was followed by a very deep minimum in the line strengths in 2008–2009.
A Composite Light Curve Model of the Symbiotic Nova PU Vul (1979)
Authors: Kato M. , Mikołajewska J. , Hachisu I. 
Published: March 2017

Abstract
PU Vul (1979) is a symbiotic nova that shows a long-lasting flat optical peak followed by a slow decline. We made a quasi-evolution model for outbursts on a 0.6 M⊙ white dwarf consisting of a series of static solutions with optically-thin winds. Our theoretical models reproduce well the observed visual/UV light curves as well as the new estimates of the temperature and radius of the hot component. We also modeled the light curve of the 1980 and 1994 eclipses as the total eclipse occulted by a pulsating M-giant companion star. In the second eclipse, the visual magnitude is dominated by nebular emission which is possibly ejected from the hot component between 1990 to 2000. We have quantitatively estimated three components of emission, i.e., the white dwarf, companion and nebular, and made a composite light curve that represents well the evolution of the PU Vul outburst.
Science Initiatives of the US Virtual Astronomical Observatory
Authors: Hanisch Robert J. 
Published: March 2017

Abstract
The United States Virtual Astronomical Observatory program is the operational facility successor to the National Virtual Observatory development project. The primary goal of the US VAO is to build on the standards, protocols, and associated infrastructure developed by NVO and the International Virtual Observatory Alliance partners and to bring to fruition a suite of applications and web-based tools that greatly enhance the research productivity of professional astronomers. To this end, and guided by the advice of our Science Council (advisory committee), we are focusing on five science initiatives in the first two years of VAO operations: (1) scalable cross-comparisons between astronomical source catalogs, (2) dynamic spectral energy distribution construction, visualization, and model fitting, (3) integration and periodogram analysis of time series data from the Harvard Time Series Center and NASA Star and Exoplanet Database, (4) integration of VO data discovery and access tools into the IR AF data analysis environment, and (5) a web-based portal to VO data discovery, access, and display tools. We are also developing tools for data linking and semantic discovery, and have a plan for providing data mining and advanced statistical analysis resources for VAO users. Initial versions of these applications and web-based services are being released over the course of the summer and fall of 2011, with further updates and enhancements planned for throughout 2012 and beyond.
The New Version of the Binary Star Database (BDB)
Authors: Kaygorodov P. , Debray B. , Kolesnikov N. , Kovaleva D. , Malkov O. 
Published: March 2017

Abstract
The Binary star database contains data on about 100 000 stellar systems of multiplicity 2 to 22, taken from a large variety of published catalogues for all types of binary stars: visual, orbital, astrometric, interferometric, spectroscopic, photometric, eclipsing, etc. Positional, kinematic, photometric, spectroscopic, orbital and astrophysical parameters are provided when available. The database can be queried by identifier, coordinates, catalogue and stellar/orbital parameters (including binary type) of objects. Lists of objects can be submitted as well. Also, the database provides links to some other online services, both of general purpose and on binary stars. A pilot version of BDB can be accessed at http://bdb.inasan.ru
UkrVO Joint Digitized Archive and Scientific Prospects
Authors: Vavilova I. B. , Pakuliak L. K. , Protsyuk Yu. I. , Shlyapnikov A. A. , Savanevich V. E. , Kondrashova N. N. , Yatsenko A. I. , Andruk V. N. 
Published: March 2017

Abstract
The UkrVO (Ukrainian Virtual Observatory) database consists of about 200 000 astronomical photographic plates and 500 000 CCD frames containing unique astronomical information for formulating important scientific tasks. This database is compiled from observations conducted in 1898-2011 at the observing sites of 8 Ukrainian observatories, with about 60 instruments. This paper deals with some principal scientific projects where the UkrVO databases are used, namely, the creation of the Joint Digitized Archive (JDA); compilation of new stellar catalogues; search for optical counterparts of gamma-ray bursts; spectroscopic study of solar flares and solar active formations; development of software for searches for new small bodies of the solar system.
Study on simultaneous adsorption of phosphate and fluoride from water environment by modified laterite ore from Northern Vietnam
Authors: Hue Nguyen Thi , Tung Nguyen Hoang 
Published: March 2017

AbstractNatural laterite can be regarded as a strong adsorbent due to its special structure and composition. In this study, the laterite was modified by manganese oxide (MnO2) to create a new good adsorbent for treating phosphate and fluoride in water environment. Under the optimized conditions of the adsorbent dose (pH 6, temperature 20°C, and the contact time 180 min), laterite, doped manganese, with diameter of grains from 0.1 to 0.5 mm has maximum adsorption capacity of 31.25 mg/g and 10.99 mg/g for phosphate and fluoride, respectively. The characteristics of the manganese doping laterite were confirmed using various techniques like SEM, BET, XRD, EDX. The adsorption process of the material was investigated by both kinetic models (pseudo-first and second orders) and isotherm models (Freundlich and Langmuir). This new material was tested for treatment of wastewater taken from the superphosphate fertilizer factory, with the results obtained showing high potential for application in reality.
Timelines and multimodal constructions: Facing new challenges
Authors: Cánovas Cristóbal Pagán , Valenzuela Javier 
Published: March 2017

Abstract
There is little doubt that spatial information underlies a great deal of our processing of temporal information. Research on the ways in which timelines are associated with specific grammatical constructions has just started, and has brought forward new challenges for construction grammar. A true multimodal construction grammar cannot be developed using the same tools and mechanisms applied so far, but will require instead a fresh approach and a careful rethinking of the whole communicative process. It is our belief than in this transition from a narrow conception of linguistic communication to a broader and more complete view of communication “in the wild”, multimodal construction grammar will play an important role.
Early Golgi Abnormalities and Neurodegeneration upon Loss of Presynaptic Proteins Munc18-1, Syntaxin-1, or SNAP-25
Authors: Santos Tatiana C. , Wierda Keimpe , Broeke Jurjen H. , Toonen Ruud F. , Verhage Matthijs 
Published: March 2017

The loss of presynaptic proteins Munc18-1, syntaxin-1, or SNAP-25 is known to produce cell death, but the underlying features have not been compared experimentally. Here, we investigated these features in cultured mouse CNS and DRG neurons. Side-by-side comparisons confirmed massive cell death, before synaptogenesis, within 1–4 DIV upon loss of t-SNAREs (syntaxin-1, SNAP-25) or Munc18-1, but not v-SNAREs (synaptobrevins/VAMP1/2/3 using tetanus neurotoxin (TeNT), also in TI-VAMP/VAMP7 knock-out (KO) neurons). A condensedcis-Golgi was the first abnormality observed upon Munc18-1 or SNAP-25 loss within 3 DIV. This phenotype was distinct from the Golgi fragmentation observed in apoptosis. Cell death was too rapid after syntaxin-1 loss to study Golgi abnormalities. Syntaxin-1 and Munc18-1 depend on each other for normal cellular levels. We observed that endogenous syntaxin-1 accumulates at the Golgi of Munc18-1 KO neurons. However, expression of a non-neuronal Munc18 isoform that does not bind syntaxin-1, Munc18-3, in Munc18-1 KO neurons prevented cell death and restored normalcis-Golgi morphology, but not synaptic transmission or syntaxin-1 targeting. Finally, we observed that DRG neurons are the only Munc18-1 KO neurons that do not degeneratein vivoorin vitro. In these neurons,cis-Golgi abnormalities were less severe, with no changes in Golgi shape. Together, these data demonstrate that cell death upon Munc18-1, syntaxin-1, or SNAP-25 loss occurs via a degenerative pathway unrelated to the known synapse function of these proteins and involving earlycis-Golgi abnormalities, distinct from apoptosis.SIGNIFICANCE STATEMENTThis study provides new insights in a neurodegeneration pathway triggered by the absence of specific proteins involved in synaptic transmission (syntaxin-1, Munc18-1, SNAP-25), whereas other proteins involved in the same molecular process (synaptobrevins, Munc13–1/2) do not cause degeneration. Massive cell death occurs in cultured neurons upon depleting syntaxin-1, Munc18-1, and/or SNAP-25, well before synapse formation. This study characterizes several relevant cellular phenotypes, especially earlycis-Golgi abnormalities, distinct from abnormalities observed during apoptosis, and rules out several other phenotypes as causal (defects in syntaxin-1 targeting and synaptic transmission). As proteins, such as syntaxin-1, Munc18-1, or SNAP-25, modulate α-synuclein neuropathy and/or are dysregulated in Alzheimer's disease, understanding this type of neurodegeneration may provide new links between synaptic defects and neurodegeneration in humans.