Detection of rovibrationally excited H2 formed through the heterogeneous recombination of H atoms on a cold HOPG surface

This paper reports results from an experiment designed to measure the nascent rovibrational population of H₂ molecules that have formed through the heterogeneous recombination of H atoms on the surface of cosmic dust analogues under conditions approaching those of the interstellar medium (ISM). H₂ that has formed on a highly oriented pyrolytic graphite (HOPG) surface has been detected, using laser induced resonance-enhanced multi-photon ionization (REMPI), in the v = 1 (J= 0–3) rovibrational states at surface temperatures of 30 K and 50 K. These excited product molecules display rotational temperatures significantly higher than the target surface temperature. These first results suggest that a considerable proportion of the binding energy released on formation of the H₂ is deposited in the surface, in addition to internal excitation of the product molecules. This revised version was published online in July 2006 with corrections to the Cover Date.     

A unique Galactic planetary nebula with a [WN] central star

We report the discovery of the first probable Galactic [WN] central star of a planetary nebula (CSPN). The planetary nebula candidate was found during our systematic scans of the AAO/UKST Hα Survey of the Milky Way. Subsequent confirmatory spectroscopy of the nebula and central star reveals the remarkable nature of this object. The nebular spectrum shows emission lines with large expansion velocities exceeding 150 km s⁻¹, suggesting that perhaps the object is not a conventional planetary nebula. The central star itself is very red and is identified as being of the [WN] class, which makes it unique in the Galaxy. A large body of supplementary observational data supports the hypothesis that this object is indeed a planetary nebula and not a Population I Wolf–Rayet star with a ring nebula.     

The Hubble relation for a comprehensive sample of QSOs

A correlation between redshifts (z) and apparent magnitudes (V) (Hubble relation) of Quasi Stellar Objects (QSOs) has long been sought. Such a correlation exists for galaxies whose redshifts are of cosmological origin. However, a plot of the two quantities representing the Hubble diagram for QSOs exhibits, in general, a wild scatter. This raises the question whether redshifts of QSOs are cosmological. On the other hand, most luminous QSOs in groups, and subsamples with particular properties, have been reported to show the Hubble relation. In the present paper, we analyse all optically non-variable QSOs in a comprehensive sample. In our analysis we grouped the objects into certain intervals of apparent magnitudes. Correlations obtained between redshifts and magnitudes are all statistically robust. Also, the Hubble relation in the usual formV = 5 logz +C is obeyed very convincingly for QSOs withV < 19.5.     

Generation of reactive oxygen species in different fractions of the coelomocytes of holothurian Eupentacta fraudatrix in response to the thermostable toxin of Yersinia pseudotuberculosis in vitro

Pure fraction (92%–95%) of phagocytes (FP) and a mixture of amoebocytes (62%) and morula cells (38%)-FPMC- of the holothurianEupentacta fraudatrix' (Holothuroidea, Dendrochirota) were obtained by using ficoll-verographine step gradient. Basal production of reactive oxygen species (ROS) in FP quantified by using reduction of nitroblue tetrazolium (NBT) was more than twice that in FPMC. Thermostable toxin ofYersinia pseudotuberculosis (TST) at different concentrations (0.2; 0.5; 2.5 μg/ml, but not 0.1 μg/ml) stimulated NBT reduction in FPMC after 24 h incubation. In FP, TST at concentrations of 0.1 and 0.2 μg/ml inhibited and at concentrations of 0.5 and 2.5 μg/ml stimulated NBT reduction after 24 h incubation. Maximal effect was observed in FP and FPMC at TST concentrations of 0.5 and 0.2 μg/ml, respectively. Addition of catalase (0.7 μg/ml) to the cells treated with TST (2.5 μg/ml) was followed by a decrease in NBT reduction compared to that under toxin treatment alone. TST stimulated superoxide dismutase activity in concentration-dependent manner (maximum at 0.5 μg/ml concentration in FP) after 24 h treatment, and this stimulation was prevented by a commercial catalase. Plant lectin concanavalin A stimulated NBT reduction more than 5-fold in FPMC compared to the control. With addition of TST, lectin stimulated ROS to lesser extent than that with lectin alone. When catalase, TST, and lectin were added into the FPMC simultaneously, ROS increase was similar to that under lectin treatment alone. On the whole, data obtained indicated that ROS generation in holothurian coelomocytes especially occurs in both stimulated and not stimulated phagocytes, and that changes in ROS production by these cells may be one of the mechanisms of antibacterial protection of holothurians. This work was financially supported by the Russian Foundation for Fundamental Research Grant (No. 00-04-48949).     

Two-Parametric Families of Orbits and Multiseparability of Planar Potentials

Combining the results of the inverse problem of dynamics with the theory of multiseparability of planar potentials, we find biparametric families of orbits, whose existence guarantees the multiseparability of the potential. We also study the allowed regions of the plane, where these orbits are traced.     

地倾斜台站数字化、模拟观测数据频率特性研究

分析了四川、云南的部分地倾斜数字化观测与模拟观测资料的特性，从频率范围，周期10天以上的FFT谱特性，固体潮波振幅，相位特征值等方面，论述了地倾斜数字化资料较模拟记录资料的信息组成变化，并对资料的分析与应用进行了初步探讨。     

Chemical Enrichment of the Intra-Cluster Medium

We investigate the metal enrichment of the intra-cluster medium by using a method that combines N-Body simulations and a semi-analytic model (SAM) of galaxy formation. The cluster of galaxies is simulated in a flat, low density universe, with a numerical resolution that allows the detection of substructures in the dark matter background of the cluster. The phenomenological approach used to model the physical processes involved in the galaxy formation and metal production is applied to the substructures found in the dark matter halos detected at different redshifts. Details of the chemical implementation in the SAM and first results related to the mean properties of the baryonic matter components are presented. This revised version was published online in August 2006 with corrections to the Cover Date.