Recent X-Ray Observations of SN1986J with ASCA and ROSAT

We present ASCA and ROSAT observations of SN 1986J covering the period 1991 August to 1996 January. From observations with the ROSAT HRI and PSPC, we find that the 0.5-2.5 keV flux decreased proportional to $t^{-2}$ during this period; the ASCA data are consistent with this result and extend it to the 2-10 keV band. ASCA spectra from 1994 January and 1996 January are consistent with thermal emission from a solar metallicity plasma at an equilibrium temperature kT = 5-7.5 keV, somewhat hotter than that observed from other X-ray supernovae. These spectra also show a clear Fe K emission line at 6.7 keV with FWHM < 20,000 km/s (90% confidence). This limit on the line width is consistent with the reverse shock model of Chevalier & Fransson (1994), but does not rule out the clumpy wind model of Chugai (1993).Comment: 20 pages, 9 postscript figures, latex, uses aastex4.0, submitted to The Astrophysical Journa

Goddard X-ray astronomy contributions to the IAU/COSPAR (1982)

The relation of X-ray flux to both the continuum flux in the optical and radio bands, and to the line emission properties of these objects were studied. The Einstein Observatory, because of increased sensitivity and improved angular resolution, increased substantially the number of known X-ray emitting active galactic nuclei. The Einstein imaging instruments detected morphology in AGN X-ray emission, in particular from jetlike structures in Cen-A, M87, and 3C273. The improved energy resolution and sensitivity of the spectrometers onboard the Observatory provide information on the geometry and ionization structure of the region responsible for the broad optical emission lines in a few AGN's. This information, combined with theoretical modeling and IUE and optical observations, allows the construction of a moderately detailed picture of the broad line region in these objects

Asymptotic Stability for a Class of Metriplectic Systems

Using the framework of metriplectic systems on $\R^n$ we will describe a constructive geometric method to add a dissipation term to a Hamilton-Poisson system such that any solution starting in a neighborhood of a nonlinear stable equilibrium converges towards a certain invariant set. The dissipation term depends only on the Hamiltonian function and the Casimir functions

Chandra and ASCA X-ray Observations of the Radio Supernova SN1979C IN NGC 4321

We report on the X-ray observation of the radio selected supernova SN1979C carried out with ASCA in 1997 December and serendipitously available from a Chandra Guaranteed Time Observation in 1999 November. The supernova, of type SN II-Linear (SN IIL), was first observed in the optical and occurred in the weakly barred, almost face on spiral galaxy NGC 4321 (M100). The galaxy, a member of the Virgo S cluster, is at a distance of 17.1 Mpc, and contains at least three other supernovae discovered in this century. The useful exposure time was ~25 ks for the Solid-State Imaging Spectrometer (SIS), ~28 ks for the Gas Scintillation Imaging Spectrometer (GIS), and ~2.5 ks for Chandra's Advanced CCD Imaging Spectrometer (ACIS). No point source was detected at the radio position of SN1979C in a 3' diameter half power response circle in the ASCA data. The background and galaxy subtracted SN signal had a 3sigma upper limit to the flux of 6.3x10^-14 ergs/s/cm^-2 in the full ASCA SIS band (0.4-10.0 keV) and a 3sigma upper limit of <3-4x10^-14 erg/s/cm^2 in the 2-10 keV band. In the Chandra data, a source at the position of SN1979C is marginally detected at energies below 2 keV at a flux consistent with the ROSAT HRI detection in 1995. At energies above 2 keV, no source is detected with an upper limit of ~3x10^-14 erg/s/cm^-2. These measurements give the first ever x-ray flux limit of a Type IIL SN above 2 keV which is an important diagnostic of the outgoing shock wave ploughing through the circumstellar medium.Comment: 8 pages, 2 figures, accepted A

Telocytes of the mammary gland stroma

Although confusions persist in what concerns the terminologies used for describing the fibroblastoid cells of the stromal compartments, the expression of antigens in such cells gradually directs their diagnosis towards a stem/progenitor phenotype. The stromal cells with long, slender and moniliform prolongations were named “telocytes” (TCs), their cell processes being termed “telopodes”. However, the mammary gland TCs were not evaluated for the CD34 expression. Thus an in vivo immunohistochemical study was designed; antibodies against CD10, CD34, CD117/c-kit and vimentin were applied on human mammary gland samples of 8 donor patients. Resident CD34-positive stromal cells positive for the TCs morphology were found building consistent stromal networks and ensheathing microvessels and excretory units. Such cells were CD10±/c-kit-/vimentin+. According to the current concepts regarding the in vivo stem/progenitor cells the CD34+ TCs of the mammary stroma could be actors in the mammary stem niche and their antigens expression could relate to different stages of differentiation

INTELLIGENT WIRELESS TECHNOLOGY USAGE EFFECT IN CONTEXT OF PHYTOSANITARY TREATMENT SPRAYING

In agriculture, pesticides and fertilizers are applied to prevent crop disease and increase plant productivity. As a result of the digitalization of agriculture, human labor is increasingly interacting with intelligent technology through robots to facilitate agricultural operations. The use of intelligent technology protects the natural ecosystem by reducing the major damage caused by the unconventional application of phytosanitary treatments resulting in a flexible, proportional spraying at precise angles, thus avoiding the generation of large amounts of chemicals. This paper presents a short review about the state of the art of wireless sensors networks and how together with robotics can be applied in different fields of agriculture through the prism of sprayers that include a detection system and a wireless controlled spraye

Recent Decisions

Comments on recent decisions by Franklin A. Morse, Joseph Freitas, J. Russell Bley, David C. Petre, Robert C. Findlay, Robert B. Cash, and Robert E. Frost

WEED CHEMICAL CONTROL ON VINEYARS

The vine is a perennial crop that can be infested with a large number of annual and perennial, monocotyledonous and dicotyledonous weed species. The damage caused by weeds to vines refers to competition from factors of vegetation, light, water, minerals, as well as the increased incidence of diseases such as blight, powdery mildew and gray rot. Weed control in the vine culture is a very important work can be done mechanically and chemically. Carrying out the autumn plowing is a mandatory work because it creates a superficial layer of loose soil, with large spaces, which determines the retention of water in the soil, at the disposal of the vine. The annual weeds are very well controlled by plowing, the seeds of which are buried in depth, thus contributing to the decrease of the degree of weeding. Perennial weeds, such as Bermuda grass, Johnson grass, field bindweed and field thistle cannot be combated by soil works because they multiply through vegetative organs. The use of herbicides on vines is beneficial because they increase production efficiently by reducing the cost of mechanical weed control. However, the application of easily leached soil herbicides can cause serious damage through root uptake and translocation to above-ground organs, including in combat. To avoid these problems, it is recommended to apply film-forming herbicides, which are very strongly absorbed on the soil surface, which does not leach into the soil and thus does not translocate into the vine plant. Such active substances act on the soil surface by stopping the emergence of weeds from the surface layer of the soil. Also, post-emergent antimonocotyledonous herbicides can be applied in the early phase of vine growth, which can control annual and perennial monocotyledonous weeds, having the advantage that they can be metabolized in the vine plant

A Broadband X-Ray Study of the Supernova Remnant 3C 397

We present an X-ray study of the radio bright supernova remnant (SNR) 3C 397 with ROSAT, ASCA, and RXTE. A central X-ray spot seen with the ROSAT High-Resolution Imager hints at the presence of a pulsar-powered component, and gives this SNR a composite X-ray morphology. Combined ROSAT and ASCA imaging show that the remnant is highly asymmetric, with its hard X-ray emission peaking at the western lobe. The spectrum of 3C 397 is heavily absorbed, and dominated by thermal emission with emission lines evident from Mg, Si, S, Ar and Fe. Single-component models fail to describe the spectrum, and at least two components are required. We use a set of non-equilibrium ionization (NEI) models (Borkowski et al. in preparation). The temperatures from the soft and hard components are 0.2 keV and 1.6 keV respectively. The corresponding ionization time-scales $n_0 t$ ($n_0$ being the pre-shock hydrogen density) are 6 $\times 10^{12}$ cm$^{-3}$ s and 6 $\times$ 10$^{10}$ cm$^{-3}$ s, respectively. The spectrum obtained with the Proportional Counter Array (PCA) of RXTE is contaminated by emission from the Galactic ridge, with only $\sim$ 15% of the count rate originating from 3C 397 in the 5-15 keV range. The PCA spectrum allowed us to confirm the thermal nature of the hard X-ray emission. A third component originating from a pulsar-driven component is possible, but the contamination of the source signal by the Galactic ridge did not allow us to find pulsations from any hidden pulsar. We discuss the X-ray spectrum in the light of two scenarios: a young ejecta-dominated remnant of a core-collapse SN, and a middle-aged SNR expanding in a dense ISM. Spatially resolved spectroscopy (with CHANDRA and XMM) is needed to differentiate between the two scenarios, and address the nature of the mysterious radio-quiet X-ray hot spot.Comment: 21 pages including 8 figures and 5 tables. Accepted for publication in the Astrophysical journa

Supernova Remnants in the Magellanic Clouds III: An X-ray Atlas of LMC Supernova Remnants

We have used archival ROSAT data to present X-ray images of thirty-one supernova remnants (SNRs) in the Large Magellanic Cloud (LMC). We have classified these remnants according to their X-ray morphologies, into the categories of Shell-Type, Diffuse Face, Centrally Brightened, Point-Source Dominated, and Irregular. We suggest possible causes of the X-ray emission for each category, and for individual features of some of the SNRs.Comment: 27 pages, 6 figures (9 figure files). To appear in the Supplement Series of the Astrophysical Journal, August 1999 Vol. 123 #