bluuebunny/crossref_metadata_2025_split huggingface dataset:
A calculation of structural parameters of spherical stellar systems by means of characteristic functions method. I. Theory
Authors: Saiyan A. P. 
Published: July 2007

AbstractTo calculate structural parameters of stellar systems such as an effective radius and central space (or surface) density, the method of characteristic functions is suggested. The characteristic function of the system is a Fourier image of their normalized space density profile f3(r). In the case of spherical symmetry the probability distribution of r (Q3(r) = (3/a3)r2f3(r)) and its orthogonal projections have the same characteristic functions. This fact is used to calculate the effective radii of a few star cluster models (King law, Plummer model and Gausian profile). It is shown, that the characteristic function for King law clusters tends to a finite generalised function if the concentration parameter c is large. The expression for the effective radius (at c ≫ 1) is given. The formula of the effective radius in the Plummer model as well as the relation between the one‐dimensional central velocity dispersion and the root mean square velocity are obtained. It is shown, that in the Gaussian model and for King law clusters the effective radius (half‐mass visual radius) can differ from the effective (harmonic) radius a few times. This fact should be taken into account in estimating the mass‐to‐light ratio from the virial mass of such systems using the King radius.
On the two‐dimensional inverse problem of dynamics
Authors: Pal A. , Anisiu M.‐C. 
Published: July 2007

AbstractThe authors extend the deduction of the equations satisfied by the force fields from inertial to rotating frames, when the curves of a certain family are known to be solutions for the equations of motion. Then Drǎmbâ's equation is obtained as a consequence of this result. The works of Hadamard and Moiseev are proved to be closely related to the inverse problem of dynamics.
Beobachtungen Kleiner Planeten. XV.
Authors: Bōrngen F. 
Published: July 2007

AbstractA summary is given about the Minor Planet survey performed in 1994 on Tautenburg Schmidt plates. 321 asteroids were observed and 1171 positions are calculated for them. These are 200 asteroids with provisional designations (102 of them have new designations) and 121 numbered objects. Tautenburg observations could give a tribute to 73 planets numbered in the period of this report. Fourteen Tautenburg asteroids have been numbered.
DIVA ‐ An interferometric minisatellite for astrometry and photometry
Authors: Bastian U. , Röserg S. , Hø E. , Mandel H. , Seifert W. , St. Wagner  , Quirrenbach A. , Schalinski C. , Schilbach E. , Wicenec A. 
Published: July 2007

AbstractWe propose a small interferometer on a minisatellite, named DIVA (Deutsches Interferometer für Vielkanalphotometrie und Astrometrie), to perform astrometric and photometric observations of at least one million stars. It would exceed the performance of Hipparcos in all important parameters. With a possible launch in 2002 DIVA would provide for all stars brighter thanV= 10m5–parallaxes better than 0.8 milliarcseconds (mas) –proper motions better than 2 mas/y –broad‐band photometry with a tyupical accuracy of 0.002 mag –multi‐channel intermediate‐band photometry with a typical accuracy of 0.01 to 0.02 mag For the 100 000 stars observed by Hipparcos, proper motions with a typical accuracy of 0.1 to 0.2 mas/y and parallaxes of 0.3 to 0.5 mas can be obtained in combination with the Hipparcos results. The scientific potential of this mission and a possible layout of its optical system are described in this paper.
Towards a cosmic no hair theorem for higher‐order gravity
Authors: Kluske S. , Schmidt H.‐J. 
Published: July 2007

AbstractWe use gravitational Lagrangians R□k √− g and linear combinations of them motivated from trials how to overcome the non‐ renormalizability of Einstein' s theory. We ask under which circumstances the de Sitter space‐ time represents an attractor solution in the set of spatially flat Friedman models. This property ensures the inflationary model to be a typical solution; nowadays, this property is called cosmic no hair theorem because it is analogous to the no hair theorem for black holes.Results are: for arbitrary k, i.e., for arbitrarily large order 2k + 4 of the field equation, one can always find examples where the attractor property takes place. Such examples necessarily need a non‐ vanishing R2‐ term. The main formulas do not depend on the dimension, so one gets similar results also for 1+1‐ dimensional gravity and for Kaluza‐ Klein cosmology.
Study of the planetary nebula NGC 2438 I. Spectroscopy of the nebula and of some cluster stars
Authors: Pauls R. , Kohoutek L. 
Published: July 2007

AbstractWe found 36 emission lines in the spectrum of the planetary nebula NGC 2438, and we determined its exc. class to be about 6–7. The nebular RVhel = 60.3 ± 3.6 km/s (5 spectra) is in agreement with RVhel = 60.8 ± 4.0 km/s of 4 cluster stars (10 spectra). We conclude that contrary to earlier statements the nebula is probably associated with the cluster.
Phase‐resolved spectroscopy and photometry of the eclipsing polar EP Draconis (=H1907+690)
Authors: Schwope A. D. , Mengel S. 
Published: July 2007

AbstractWe present phase‐resolved optical spectroscopy and CCD photometry of the faint eclipsing polar EP Dra (H1907+690). A revised ephemeris is derived which connects all 32000 binary cycles since its discovery by Remillard et al. (1991). We found no difference between spin and and orbital periods of the white dwarf. Changes in the light curve morphology are attributed to a different beaming behaviour which might change on timescales as short as one or several orbital periods. Optical light curve modelling was used to estimate the co‐latitude of the accretion spot, which must be larger than 40°. We have detected Zeeman absorption lines of Hα originating in an accretion halo in a field of 16 MG. The low‐resolution spectra reveal no indication of resolved cyclotron harmonics, which is also suggestive of a relatively low field strength in the accretion region. The Balmer emission lines contain significant contributions from the UV‐illuminated hemisphere of the companion star, whereas the Hell λ4686 emission originates predominantly from the accretion stream. The emission lines have a multi‐component structure and we could single out a narrow emission line in the Hβ and Hγ lines. It radial velocity amplitude suggests a low mass for the white dwarf, if the lines are interpreted as being of reprocessed origin from the whole illuminated hemisphere of the companion star.
Astronomical refraction: formulas for all zenith distances
Authors: Wittmann A. D. 
Published: July 2007

AbstractIn real‐time applications fast and accurate algorithms for calculating astronomical refraction are required. Some of the most widely‐used expressions are fast, but numerically unstable, and can not be applied where the correction is largest, i.e. close to the horizon. In the present paper a new formula for refraction, which is both fast and numerically stable, is given and compared with previously published refraction formulas. The approximate calculation of refraction 'below the horizon', and of the finite distance correction near the horizon, are also discussed.
Composite lightcurve of asteroid Moskva (787)
Authors: Greve T. R. , Pontoppidan K. M. , Olsen H. J. F. 
Published: July 2007

Abstract89 CCD frames of the asteroid Moskva (787) were obtained over six nights. Lightcurves have been acquired for each night. We suggest a possible composite lightcurve with a corresponding rotational period of 0.4 days. This is to the knowledge of the authors the first lightcurve of Moskva(787) to be published.
Ultrasoft narrow‐line Seyfert 1 galaxies and X‐ray surveys
Authors: Brandt N. , Boller T. 
Published: July 2007

AbstractNote from the editor: This article is a re‐print of the original, which appeared in Astron. Nachr. 319 (1/2), 7 (1998). In the original version the figure was ruined in the process of paper production and the scientific content of the paper considerably degraded. Instead of printing only the correct figure, thus loosing the scientific context, we decided to re‐print the whole article.We describe how recent X‐ray surveys have led to advances in the understanding of ultrasoft narrow‐line Seyfert 1 galaxies. The number of known ultrasoft narrow‐line Seyfert 1s has increased greatly in recent years due to X‐ray surveys, and it is now possible to obtian high quality 0.1–10 keV spectral and variability measurements for a large number of these galaxies. We generalize some of the correlations between X‐ray properties and optical emission line properties,focusing on how the ROSAT band spectral slope appears to be directly connected to the Boroson & Green (1992) primary eigenvector. We discuss how ultrasoft narrow‐line Seyfert 1s may well have extremal values of a primary physical parameter, and we describe new projects that should further improve our understanding of these extreme representatives of Seyfert activity.
Early versus late type galaxies in compact groups
Authors: Shaker A. A. , Longo G. , Merluzzi P. 
Published: July 2007

AbstractWe find a strong correlation between the effective radius of the largest early‐type galaxies in compact groups of galaxies and the velocity dispersion of the groups. The lack of a similar correlation for late type galaxies is supportive of the so called second generation merging scenario which predicts that ellipticals should dominate the internal dynamics of the groups, while late‐type galaxies are mainly recent interlopers which are still in an early stage of interaction with the group potential.
Schmidt plate survey in the Galactic centre and anticentre direction. Luminosity and mass functions of open clusters
Authors: Kharchenko N. , Meusinger H. , Piskunov A. , Schilbach E. 
Published: July 2007

AbstractThe proper motions and stellar magnitudes for more than 20 000 stars distributed in areas around eight open clusters in the directions of the Sagittarius‐Carina and Perseus spiral arms were used to determine the cluster membership. Both spatial‐kinematical and statistical criteria were used for member seletion. The luminosity functions of cluster members were constructed and used for the further data improvement. The safest portions of the luminosity function free both from evolved stars and faint field star contamination were used for mass function construction. The composite mass function was derived from the data on five young clusters with log t < 8.2. A dependence of the mass function slope on the adopted input parameters (mass‐luminosity relation and distance scale) and on member selection procedure was tested. The slope was found to vary in a range from 1.36 to 1.80 for lg M/M⊙ between 0.3 and 1.2. A possible relation between the individual MF slopes and cluster ages was indicated. The results are in good agreement with published data.
Quasar evolution
Authors: Wisotzki L. 
Published: July 2007

AbstractI present a critical review of recent progress in the field of quasar evolution, concentrating on the methodical issues of constructing and analysing observed quasar samples. In particular, I attempt to trace the origins and shortcomings of the popular concept of ‘pure luminosity evolution’ that has dominated the discussion over the last decade. I discuss results from new surveys showing that this notion should be abandoned, and that quasar evolution is more complex than previously thought.
Aberration and relativity
Authors: Liebscher D.‐E. , Brosche P. 
Published: July 2007

AbstractThe aberration of starlight seems to be one of the simplest phenomena of astronomical observation. However, the story of misunderstandings is long and lasts till now. It is nearly forgotten that the problem of stellar aberration was the cornerstone of the development and the acceptance of relativity. In addition, there seems to be no essentially final point in the discussion of its interpretation, the discussion seems to merely be given up. Of course, with the correct relativistic formulas, there is no need of interpretation any more. The price of this consists in the many incorrect descriptions and interpretations that arise if a textbook tries to explain in words the mere formulas. We try to review the problems discussed in the last three centuries and to give them a final, i.e. geometrical form. We are convinced that this teaches a lot about the geometry of the space‐time union.
The ROSAT Bright Survey: I. Identification of an AGN sample with hard ROSAT X‐ray spectra
Authors: Fischer J.‐U. , Hasinger G. , Schwope A. D. , Brunner H. , Boller T. , Trümper J. , Voges W. , Neizvestny S. 
Published: July 2007

AbstractThe ROSAT Bright Survey (RBS) aims to completely optically identify the more than 2000 brightest sources detected in the ROSAT all‐sky survey at galactic latitudes |b| > 30° (excluding LMC, SMC, Virgo cluster). This paper presents a subsample of 66 bright point‐like ROSAT survey sources with almost hard PSPC spectra, the hardness ratio HR1 is > 0.5 for most of the sources. Teh subsample could be nearly completely identified by low‐resolution optical spectroscopy with the following breakdown into object classes: 31 Seyfert galaxies, 22 BL Lac candidates, 5 clusters of galaxies, 1 cataclysmic variable, and 5 bright stars. Only one object remained unidentified and one X‐ray source was a spurious detection. The redshift distrbution peaks around 0.06 for the Seyferts and around 0.13 for the BL Lac candidates. Observations with medium spectral resolution were obtained for most of the new Seyfert galaxies. A large fraction (20 objects) are type 1 Seyfert galaxies, the other fraction includes Seyfert galaxies of type 1.5 – 1.8 (5 objects), two LINERs, and 4 possible narrow‐line Seyfert 1 galaxies (NLS1). About one third of the new Seyfert's have nearby companion galaxies displaying either emission or absorption lines at the same redshift. Among them are a couple of systems showing direct morphological evidence for interaction. The large fraction of interacting galaxies among our sample suggests a scenario where interaction is the main trigger of AGN activity.
The Solar granulation in different heights
Authors: Balthasar H. 
Published: July 2007

AbstractIntensity images and Doppler‐velocity maps of the quiet sun in different heights are obtained from simultaneously recorded spectra of different lines. A relation between the intensity images is recognizable up to formation heights of 900 km above continuum, but the correlation coefficient changes sign above 400 km. The core of Hα shows a different pattern without any correlation to the continuum layer. Extreme Doppler velocities as well as the rms‐velocities have minima at a height of 400 km, values of about 2 km/s occur in deep photospheric layers and 2.5 km/s in a height of 900 km. The velocities in the lower and in the upper photosphere are well correlated indicating that the pattern of the velocity field is preserved up to higher layers than the intensity pattern. Hα‐velocities reach values up to 10 km/s and more, they show no correlation with the continuum intensities and almost no with the line core intensities.
Influence of chronic hepatic failure on disposition kinetics of valproate excretion through a phase II reaction in rats treated with carbon tetrachloride
Authors: Khemawoot Phisit , Maruyama Chiharu , Tsukada Hirotaka , Noda Hiroyo , Ishizaki Junko , Yokogawa Koichi , Miyamoto Ken‐ichi 
Published: July 2007

AbstractThe influence of chronic hepatic failure on the disposition kinetics of valproate (VPA) excretion via a phase II reaction was examined in rats treated with carbon tetrachloride (1.0 mg/kg, s.c., 3 times a week) for 2 or 3 months. There was no significant difference in the plasma concentration‐time courses of VPA among the control and two treated groups up to 120 min after i.v. administration of VPA (75 mg/kg), but subsequently the plasma concentrations of the treated groups declined significantly below the control levels. Expression of Mrp2 mRNA in the liver of the treated groups was significantly lower than in the control group; conversely that in the kidney was significantly higher. The enzyme activity of UGTs in the liver of the treated groups decreased significantly, but UGT1A8 mRNA expression in the duodenum was increased about 3‐fold. Cumulative excretion of VPA glucuronide (VPA‐G) in bile of the treated groups was reduced significantly, while that in urine was markedly increased. In conclusion, the area under the VPA plasma concentration‐time curve was decreased significantly in rats with chronic hepatic failure owing to increased excretion of VPA‐G via the kidney as a result of induction of Mrp2, and inhibition of enterohepatic circulation of VPA‐G. Copyright © 2007 John Wiley & Sons, Ltd.
Deleterious effects of polynuclear aromatic hydrocarbon on blood vascular system of the rat fetus
Authors: Sanyal Mrinal K. , Li You‐Lan 
Published: July 2007

AbstractBACKGROUND: Polynuclear aromatic hydrocarbons (PAH), benzo[α]pyrene (B[α]P) and 7,12‐dimethylbenz[α]anthracene (DMBA) are toxic environmental agents distributed widely. The relative deleterious effects of these agents on growth and blood vasculature of fetus and placental tissues of the rat were studied. METHODS: Pregnant rats (Day 1 sperm positive) with implantation sites confirmed by laparotomy were treated intraperitoneally (i.p.) on Pregnancy Days 10, 12, and 14 with these agents dissolved in corn oil at cumulated total doses 50, 100, and 200 mg/kg/rat, and control with corn oil only (3–20 dams/group). Fetal growth, tissue hemorrhage, and placental pathology were evaluated by different parameters on Pregnancy Day (PD) 20 in treated and control rats. RESULTS: DMBA was relatively more deleterious compared to B[α]P indicated by increased lethality and progressive reduction of body weight of the mother with increasing doses. At 200 mg/kg/rat doses of these agents, maternal survival was 45% and 100% and body weight reduced 24% and 52% of controls, respectively. The fetal survival rates in live mothers were similar to that of controls. They induced marked fetal growth retardation and necrosis of placental tissues. B[α]P and DMBA produced significant toxicity to differentiating fetal blood vascular system as exhibited by rupture of blood vessels and hemorrhage, especially in the skin, cranial, and brain tissues. CONCLUSIONS: Maternal PAH exposure induced placental toxicity and associated adverse fetal development and hemorrhage in different parts of the fetal body, in particular, marked intradermal and cranial hemorrhage, showing that developing fetal blood vasculature is a target of PAH toxicity. Birth Defects Res (PartB), 2007. © 2007 Wiley‐Liss, Inc.
Russia through the prism of the world biopharmaceutical market
Authors: Bairamashvili Dmitrij I. , Rabinovich Mikhail L. 
Published: July 2007

AbstractTrends in the Russian pharmaceutical biotechnology and related fields representing the major sector of domestic biotech are reviewed through the prism of the world biopharmaceuticals market. A special emphasis is placed on biogenerics and follow‐on biologics. The revival of national pharmbiotech is seen in close cooperation between private companies and the state, academia and industry. One of the first positive steps toward promoting development of domestic biopharmaceuticals is the Federal Program of subsidized supply of expensive pharmaceuticals (Dopolnitel'‐ noe Lekarstvennoe Obespechenie). The program allows the Russian government to purchases expensive drugs to be provided free of cost to certain preferential categories of individuals. As an example, production of recombinant human insulin by the largest Russian fundamental biotechnological institute, Shemyakin‐Ovchinnikov Institute of Bioorganic Chemistry under the trademark Insuran (Insulin produced by the Russian Academy of Science) is reviewed. Some prospects and problems of Russian biotech research related to medical area are briefly discussed.
Electron‐Transfer Reactions through the Associated Interaction between Cytochrome c and Self‐Assembled Monolayers of Optically Active Cobalt(III) Complexes: Molecular Recognition Ability Induced by the Chirality of the Cobalt(III) Units
Authors: Takahashi Isao , Inomata Tomohiko , Funahashi Yasuhiro , Ozawa Tomohiro , Masuda Hideki 
Published: July 2007

AbstractSelf‐assembled monolayers (SAMs) of optically active CoIII complexes ((S)‐2/(R)‐2) that contain (S)‐ or (R)‐phenylalanine derivatives as a molecular recognition site were constructed on Au electrodes ((S)‐2–Au/(R)‐2–Au). Molecular recognition characteristics induced by the S and R configurations were investigated by measurements of electron‐transfer reactions with horse heart cytochrome c (cyt c). The electrochemical studies indicate that the maximum current of cyt c reduction is obtained when the Au electrode is modified by 2 with a moderate coverage of approximately 4.0×10−11 mol cm−2. Since the Au electrode is not densely packed with the CoIII units at this concentration, we conclude that the penetrative association process between cyt c and the CoIII unit plays an important role in this electron‐transfer system. The differences in the electron‐transfer rates of (S)‐2–Au and (R)‐2–Au increase with increasing scan rates, a result indicating that the chiral ligand has an influence on the rate of association of the complexes with cyt c. 3–Au has a mixed monolayer composed of 2 and hexanethiol and exhibits electron‐transfer behavior comparable to 2–Au. The difference in the association rates of (S)‐3–Au and (R)‐3–Au is larger than that between (S)‐2–Au and (R)‐2–Au, which indicates that the molecular recognition ability of 3–Au has been enhanced by filling the gap between molecules of 2 with hexanethiols. The differences in the oxidation rates of cyt cII between (S)‐2–Au and (R)‐2–Au and between (S)‐3–Au and (R)‐3–Au were larger than the differences in the rates of the reduction of cyt cIII; this suggests that the size of the heme crevice varies according to the oxidation state of cyt c.
The Rates of SN2 Reactions and Their Relation to Molecular and Solvent Properties
Authors: Arnaut Luis G. , Formosinho Sebastião J. 
Published: July 2007

AbstractThe energy barriers of symmetrical methyl exchanges in the gas phase have been calculated with the reaction path of the intersecting/interacting‐state model (ISM). Reactive bond lengths increase down a column of the Periodic Table and compensate for the decrease in the force constants, which explains the near constancy of the intrinsic barriers in the following series of nucleophiles: F−≈Cl−≈Br−≈I−. This compensation is absent along the rows of the Periodic Table and the trend in the reactivity is dominated by the increase in the electrophilicity index of the nucleophile in the series C<N<O<F. Solvent effects have been quantitatively incorporated into the ISM model through a correlation between electrophilicity and the solvent acceptor number. This correlation is transferable between nucleophiles and solvents and allows the methyl transfer rate constants in solution to be calculated with remarkable simplicity and accuracy. The relationship between the SN2 and electron‐transfer mechanisms is clarified and it is shown that smaller solvent static effects should be expected for electron transfer in the absence of a thermodynamic driving force.