First Record of the Mosquitoes \u3ci\u3eAedes Dupreei Psorophora Horrida,\u3c/i\u3e and \u3ci\u3ePsorophora Mathesoni\u3c/i\u3e (Diptera: Culicidae) in St. Joseph County, Indiana

(excerpt) Adult females of Aedes (Ochlerotatus) dupreei (Coquillett), Psorophora (lanthinosoma) horrida (Dyar and Knab), and Psorophora (Janthinosoma) mathesoni (Belkin and Heinemann) were collected on 18 and 19 June 1981, in an oak woodlot in South Bend, Indiana

The NASA Ground Network Vision for the Future

This paper will highlight the GN's mission, motivation, and future plans, specifically in relation to the increase of commercialization for routine services and partnership opportunities for routine and unique services with the goal that other agencies can benefit from our approach as they pursue their science and exploration goals

Uptake of heavy metals, organic trace contaminants and viruses by the Japanese oyster, Crassostrea gigas, grown in a waste recycling aquaculture system : final report

A study of 24 weeks duration was carried out in which oysters (Crassostrea gigas) were grown in four regimes. These were: (i) on phytoplankton cultured in a mixture of secondary treated sewage effluent and seawater for a period of 12 weeks followed by a second 12 week period of feeding on phytoplankton cultured in a "clean," inorganically enriched regime; (ii) as for (i) except that the secondary effluent was sand filtered prior to use; (iii) as for (ii) except that the effluent was charcoal filtered prior to use; and (iv) using "clean," inorganically enriched phytoplankton food for the 24 week duration. At intervals of two weeks, populations of oysters were removed for assay for trace metals (Cd, Cr, Cu, Hg, Ni, Pb, Zn) and organic contaminants (hydrocarbons, P . C.B.' s). No significant accumulation or depuration of any metal or organic contaminant was evident in any of the regimes. In terms of these contaminants all oysters are within acceptable edible standards as set by F.D.A. A series of experiments was carried out to examine the public health implications of enterovirus survival in a mollusc culture system fertilized with secondary treated sewage effluent. Using MS-2 bacteriophage and vaccine strain poliovirus it would appear that depuration could be effected in 20-25 days in C. gigas at l5°C. However this does NOT mean that such a time span would be adequate for other enteroviruses. Further work is required in this area.Supported by NOAA Office of Sea Grant, Department of Commerce, Grant No. 04-07-158-44104

Filling in the Gaps in the 4.85 GHz Sky

We describe a 4.85 GHz survey of bright, flat-spectrum radio sources conducted with the Effelsberg 100 m telescope in an attempt to improve the completeness of existing surveys, such as CRATES. We report the results of these observations and of follow-up 8.4 GHz observations with the VLA of a subset of the sample. We comment on the connection to the WMAP point source catalog and on the survey's effectiveness at supplementing the CRATES sky coverage.Comment: 13 pages, 3 figures, 2 tables. Accepted for publication in the Astronomical Journal. Tables available in electronic form: http://astro.stanford.edu/gaps

ECOREGIONAL DIFFERENCES IN LATE-20TH-CENTURY LAND-USE AND LAND-COVER CHANGE IN THE U.S. NORTHERN GREAT PLAINS

Land-cover and land-use change usually results from a combination of anthropogenic drivers and biophysical conditions found across multiple scales, ranging from parcel to regional levels. A group of four Level III ecoregions located in the u.s. northern Great Plains is used to demonstrate the similarities and differences in land change during nearly a 30-year period (1973-2000) using results from the U.S. Geological Survey\u27s Land Cover Trends project. There were changes to major suites of land-cover; the transitions between agriculture and grassland/shrubland and the transitions among wetland, water, agriculture, and grassland/shrubland were affected by different factors. Anthropogenic drivers affected the land-use tension (or land-use competition) between agriculture and grassland/shrubland land-covers, whereas changes between wetland and water land-covers, and their relationship to agriculture and grassland/shrubland land-covers, were mostly affected by regional weather cycles. More land-use tension between agriculture and grassland/shrubland landcovers occurred in ecoregions with greater amounts of economically marginal cropland. Land-cover change associated with weather variability occurred in ecoregions that had large concentrations of wetlands and water impoundments, such as the Missouri River reservoirs. The Northwestern Glaciated Plains ecoregion had the highest overall estimated percentage of change because it had both land-use tension between agriculture and grassland/shrubland land-covers and wetland-water changes

Understanding the Geometry of Astrophysical Magnetic Fields

Faraday rotation measurements have provided an invaluable technique with which to measure the properties of astrophysical magnetized plasmas. Unfortunately, typical observations provide information only about the density-weighted average of the magnetic field component parallel to the line of sight. As a result, the magnetic field geometry along the line of sight, and in many cases even the location of the rotating material, is poorly constrained. Frequently, interpretations of Faraday rotation observations are dependent upon underlying models of the magnetic field being probed (e.g., uniform, turbulent, equipartition). However, we show that at sufficiently low frequencies, specifically below roughly 13 (RM/rad m^-2)^(1/4) (B/G)^(1/2) MHz, the character of Faraday rotation changes, entering what we term the ``super-adiabatic regime'' in which the rotation measure is proportional to the integrated absolute value of the line-of-sight component of the field. As a consequence, comparing rotation measures at high frequencies with those in this new regime provides direct information about the geometry of the magnetic field along the line of sight. Furthermore, the frequency defining the transition to this new regime, nu_SA, depends directly upon the local electron density and magnetic field strength where the magnetic field is perpendicular to the line of sight, allowing the unambiguous distinction between Faraday rotation within and in front of the emission region. Typical values of nu_SA range from 10 kHz to 10 GHz, depending upon the details of the Faraday rotating environment. In particular, for resolved AGN, including the black holes at the center of the Milky Way (Sgr A*) and M81, nu_SA ranges from roughly 10 MHz to 10 GHz, and thus can be probed via existing and up-coming ground-based radio observatories.Comment: 13 pages, 5 figures, submitted to Ap

Radio polarimetric imaging of the interstellar medium: magnetic field and diffuse ionized gas structure near the W3/W4/W5/HB3 complex

We have used polarimetric imaging to study the magneto-ionic medium of the Galaxy, obtaining 1420 MHz images with an angular resolution of 1' over more than 40 square-degrees of sky around the W3/W4/W5/HB3 HII region/SNR complex in the Perseus Arm. Features detected in polarization angle are imposed on the linearly polarized Galactic synchrotron background emission by Faraday rotation arising in foreground ionized gas having an emission measure as low as 1 cm^{-6} pc. Several new remarkable phenomena have been identified, including: mottled polarization arising from random fluctuations in a magneto-ionic screen that we identify with a medium in the Perseus Arm, probably in the vicinity of the HII regions themselves; depolarization arising from very high rotation measures (several times 10^3 rad m^{-2}) and rotation measure gradients due to the dense, turbulent environs of the HII regions; highly ordered features spanning up to several degrees; and an extended influence of the HII regions beyond the boundaries defined by earlier observations. In particular, the effects of an extended, low-density ionized halo around the HII region W4 are evident, probably an example of the extended HII envelopes postulated as the origin of weak recombination-line emission detected from the Galactic ridge. Our polarization observations can be understood if the uniform magnetic field component in this envelope scales with the square-root of electron density and is 20 microG at the edge of the depolarized region around W4, although this is probably an over-estimate since the random field component will have a significant effect.Comment: 18 pages, 8 figures (7 jpeg and 1 postscript), accepted for publication in the Astrophysical Journa

G55.0+0.3: A Highly Evolved Supernova Remnant

Multi-frequency analysis has revealed the presence of a new supernova remnant, G55.0+0.3, in the Galactic plane. A kinematic distance of 14 kpc has been measured from HI spectral line data. The faint, clumpy half-shell is non-thermal and has a physical radius of 70 pc. Using an evolutionary model, the age of the remnant is estimated to be on the order of one million years, which exceeds conventional limits by a factor of five. The remnant may be associated with the nearby pulsar J1932+2020, which has a spin-down age of 1.1 million years. This work implies that the radiative lifetimes of remnants could be much longer than previously suggested.Comment: 27 pages, 7 figures in 9 files (figures 1 and 2 require 2 files each), Accepted for publication in The Astrophysical Journal (Jan. 20, 1998 volume