We present the results of a systematic search for Xray flares on young stars observed during ROSAT PSPC observations of the Taurus-Auriga-Perseus sky region. All pointed PSPC observations currently available from the ROSAT Public Data Archive with known pre-main sequence T Tauri Stars or young Pleiads or Hyads in the field of view are analyzed. A study of the activity of late-type stars of diff...

We present the results of a systematic search for Xray flares on young stars observed during ROSAT PSPC observations of the Taurus-Auriga-Perseus sky region. All pointed PSPC observations currently available from the ROSAT Public Data Archive with known pre-main sequence T Tauri Stars or young Pleiads or Hyads in the field of view are analyzed. A study of the activity of late-type stars of diff...

A 1.0 kb region of the mitochondrial cytochrome oxidase subunit I gene from the greenbug aphid, Schizaphis graminum (Rondani), was sequenced for 24 field collected clones from non-cultivated and cultivated hosts. Maximum likelihood, maximum parsimony and neighbour-joining phylogenies were estimated for these clones, plus 12 previously sequenced clones. All three tests produced trees with identi...

We model the process of dust coagulation in protoplanetary disks and calculate how it affects their observational appearance. Our model involves the detailed solution of the coagulation equation at every location in the disk. At regular time intervals we feed the resulting 3D dust distribution functions into a continuum radiative transfer code to obtain spectral energy distributions. We find th...

We present high resolution optical spectra obtained with the HIRES spectrograph on the W. M. Keck I telescope of seven low mass T Tauri stars and brown dwarfs (LMTTs) in Taurus-Auriga. The observed Li I 6708 Å absorption, low surface gravity signatures, and radial velocities confirm that all are members of the Taurus star forming region; no new spectroscopic binaries are identified. Four of the...

Abstract. Purpose. The research is aimed at developing methods for creating highly productive and nutritious pasture agrophytocenoses, adapted to the extreme conditions of arid zone Northern Caspian region. Methods. paper provides an assessment productivity perennial one-species (Agropyron) poly-species (Agropyron, Eutoria, Kochia) agrophytocenoses a five-year period their vegetation, depending...

The genomes of five Agropyron Gaertner, 1770 species were characterized using all potential di- or trinucleotide simple sequence repeat (SSR) motifs and four satellite DNA repeats as fluorescence in situ hybridization (FISH) probes. The sites of 5S and 45S rDNA were relatively conserved among the diploid and tetraploid species. A number of sites for the dinucleotide SSRs AC, AG, and pSc119.2 wa...

The objective of these studies was to compare preference for leafy spurge (Euphorbiu es& L.) by sheep and goats. Study 1 was a choice test that paired leafy spurge with either arrowleaf balsamroot (Balsamorhiza sagittata (Pursh)Nutt.) or crested wheatgrass (Agropyron cristatum (L.)Gaertn.) for a 30 minute feeding period. Study 2 consisted of 3 grazing trials on spurgeinfested pastures. Differen...

The present study was conducted to examine photosynthetic characteristics of three dominant grass species (Agropyron cristatum, Leymus chinensis, and Cleistogenes squarrosa) and their responses to burning and nitrogen fertilization in a semiarid grassland in northern China. Photosynthetic rate (P(n)), stomatal conductance (g(s)), and water use efficiency (WUE) showed strong temporal variability...