Gas in galactic disks is collected by gravitational instabilities into giant atomic-molecular complexes, but only the inner, molecular parts of these structures are able to collapse to form stars. Determining what controls the ratio of atomic to molecular hydrogen in complexes is therefore a significant problem in star formation and galactic evolution. In this paper we use the model of H2 forma...

We construct models of molecular clouds that are considered as ensembles of transient cores. Each core is assumed to develop in the background gas of the cloud, grow to high density and decay into the background. The chemistry in each core responds to the dynamical state of the gas and to the gas-dust interaction. Ices are deposited on the dust grains in the core’s dense phase, and this materia...

We present Submillimeter Wave Astronomy Satellite (SWAS) observations of the 110 → 101 transition of orthoH2O at 557 GHz toward 12 molecular cloud cores. The water emission was detected in NGC 7538, ρ Oph A, NGC 2024, CRL 2591, W3, W3(OH), Mon R2, and W33, and was not detected in TMC-1, L134N, and B335. We also present a small map of the H2O emission in S140. Observations of the H18 2 O line we...

alfvén waves dissipation is an extensively studied mechanism for the coronal heating problem. these waves can be generated by magnetic reconnection and propagated along the reconnected field lines. here, we study the generation of alfvén waves at the presence of both steady flow and sheared magnetic field in the longitudinally density stratified of solar spicules. the initial flow is assumed to...

in this paper, a new approach for estimating the number of wideband sources is proposed which is based on rss or ism algorithms. numerical results show that the mdl-based and eit-based proposed algorithm havea much better detection performance than that in egm and aic cases for small differences between the incident angles of sources. in addition, for similar conditions, rss algorithm offers hi...

We mapped a 13×22 pc region in emission from 492 GHz [C I] and, for the first time, 551 GHz 13CO(5→4) in the giant molecular cloud M17SW. The morphologies of the [C I] and 13CO emission are strikingly similar. The extent and intensity of the [C I] and 13CO(5→4) emission is explained as arising from photodissociation regions on the surfaces of embedded molecular clumps. Modeling of the 13CO(5→4)...

New early release observations of the Cepheus E outflow and its embedded source, obtained with the Spitzer Space Telescope, are presented. We show the driving source is detected in all 4 IRAC bands, which suggests that traditional Class 0 classification, although essentially correct, needs to accommodate the new high sensitivity infrared arrays and their ability to detected deeply embedded sour...

We present deep narrowband near-IR images and moderate resolution spectra of the young planetary nebula Hubble 12. These data are the first to show clearly the complex structure for this important planetary nebula. Images were obtained at λ = 2.12, 2.16, and 2.26 μm. The λ = 2.12 μm image reveals the bipolar nature of the nebula, as well as complex structure near the central star in the equator...

We present deep narrowband near-IR images and moderate resolution spectra of the young planetary nebula Hubble 12. These data are the first to show clearly the complex structure for this important planetary nebula. Images were obtained at λ = 2.12, 2.16, and 2.26 μm. The λ = 2.12 μm image reveals the bipolar nature of the nebula, as well as complex structure near the central star in the equator...

Abstract Purpose-The purpose of this paper is to review a sample of the literature relating to Interpretive Structural Modelling (ISM) and its deployment for modelling purposes in the area of supply chain management (SCM). Design/methodology/approach- The literature is examined from the three perspectives. First, concept of ISM and examines ISM as modelling technique. Second, use of ISM by ...