A molecular Einstein ring: imaging a starburst disk surrounding a quasi-stellar object

Images of the molecular CO 2-1 line emission and the radio continuum emission from the redshift 4.12 gravitationally lensed quasi-stellar object (QSO) PSS J2322+1944 reveal an Einstein ring with a diameter of 1.5". These observations are modeled as a star-forming disk surrounding the QSO nucleus with a radius of 2 kiloparsecs. The implied massive star formation rate is 900 solar masses per year. At this rate, a substantial fraction of the stars in a large elliptical galaxy could form on a dynamical time scale of 108 years. The observation of active star formation in the host galaxy of a high-redshift QSO supports the hypothesis of coeval formation of supermassive black holes and stars in spheroidal galaxies.     

Comparison of Point Intercept and Image Analysis for Monitoring Rangeland Transects

There is global recognition that sustainable land use requires monitoring that will detect change on a scale that protects the resource. That fundamental necessity is threatened where labor-intensive methods and high labor costs cause sampling deficiencies and increased Type-II error rates (false negatives). Ground-based imaging is a monitoring method that reduces monitoring labor costs. Nadir (vertical) images acquired with common digital cameras can be manually analyzed for cover using free software. We used an innovative field protocol to acquire standardized, freehand, nadir images (samples) of rangeland, then compared point intercept (PI) and image-analysis techniques. Between methods, precision (repeatability) across users was equivalent; cover measurements were often different, and the image-analysis technique took only a third as long to complete. Image analysis has several advantages over PI besides the reduced labor cost: Images are permanent resource records available for reanalysis if data are questioned, if software improves, or if management objectives change; and image analysis is less biased by moving vegetation, moving pointing devices, and bright vegetation color.     

The absorption of tritium gas by english soils,plants and the sea

The absorption of T₂ gas by several grassland soils was measured in situ using a small chamber. The deposition velocity for the process ranged from 0.01 to 0.1 cm s^?1, and varied more with season than with soil type or temperature of the soil surface. Laboratory and field experiments showed that the soil, and not the vegetation, was the sink for T₂. The T₂ lost from the air was readily available in soil water. Deposition to sea water was also measured. The sea surface was found to be a negligible sink in comparison to soil. The dose rate to people living near a release of T₂ gas to the atmosphere, due to contamination of food and water, is estimated to be about one-eighth of that which would be caused by an equal release of HTO vapor.     

A soil-diagnostic key to manage saline and waterlogged catchments in the Mt Lofty Ranges, South Australia

Abstract. Dryland salinity in the Mt Lofty Ranges, South Australia has developed as a result of native vegetation being replaced with pastures that use less water. Groundwaters have risen and mobilized ions (sodium, chloride, sulphate and iron) stored within deeply weathered micaceous sandstones and schists. Salinity resulting from sodium chloride is common in agricultural catchments around Australia, but saline sulphidic soils (with sulphate and iron) have only been studied in South Australia. Salinity is also associated with waterlogging and secondary sodicity. The amelioration of dryland salinity and waterlogging involves management of whole catchments, not just the area that is currently saline. It is imperative that all processes operating in saline catchments and their interactions are clearly understood.
Salinity, waterlogging, sodicity, sulphidization and water erosion were studied in four saline sub-catchments in the Mt Lofty Ranges. Grey (bleached) and yellow mottles (iron depletions) or black and red stains (iron concentrations) develop under certain conditions of water saturation, salinization, sulphidization, sodification and water erosion in surface and subsurface horizons. The amounts of these diagnostic features were used to develop a farm planning key for managing saline catchments in the Mt Lofty Ranges. Using soil diagnostic features, soil-water processes in saline catchments are easily identified by farmers and land managers. Management options (e.g. fencing, tree planting and drainage) are then targeted to specific soils and can be easily incorporated by agricultural advisers into farm management plans. We recommend that soil diagnostic features which help predict the onset of land degradation be used in the production of land capability maps for farm planning purposes.     

Effects of fungal inocula on the decomposition of lignin and structural polysaccharides in Pinus sylvestris litter

 Litter bags containing sterile Scots pine (Pinus sylvestris) needles (19.8% lignin, 26.5% cellulose and 0.34% N) were inoculated with two species of fungi in the laboratory and then placed in the litter layer of a pine plantation. Marasmius androsaceus, which can degrade lignocellulose, was initially displaced by other fungal colonisers and was not detected in the litter after 2–3 months; but was re-isolated from the needles after 12 months. Trichoderma viride, which is a cellulolytic species and also antagonistic to other fungi, dominated the litter throughout the experiment. The control litter was naturally colonised by litter fungi. After 12 months, mass losses were similar at 52% for M. androsaceus and 48% for T. viride, compared with 36% for the control litter colonised by a more complex fungal community. Lignin concentrations increased with time in control litter and with T. viride because mass losses of carbohydrates were greater than those of lignin. Litter inoculated with M. androsaceus showed significant lignin decomposition throughout the experiment but cellulose concentrations showed a proportional increase in the first 6 months, suggesting that the fungus was preferentially exploiting hemicellulose and non-structural carbohydrates. Analysis of TFA-extractable sugars (mainly from hemicellulose) and CuO-derived phenylpropanoid moieties from lignin confirmed the differential patterns of resource decomposition which were not evident from total mass losses. During the initial stages of decomposition, T. viride was as effective in utilising structural polysaccharides as the complex fungal community in the control litter. Furthermore, M. androsaceus not only exhibited unexpectedly low cellulolytic activity but also facilitated lignin depolymerisation after the fungus was no longer detectable in the litter. The pre-inoculation of litter with these two fungal species therefore affected the overall dynamics of decomposition at a biochemical level. This study illustrates the importance of understanding the effects and interactions of specific fungi, rather than assumptions about the functional competence of diverse communities, on the processes of litter decomposition. Received: 5 July 2000     

Quantifying the fine scale (1km × 1km) exposure,dose and effects of ozone: Part 2 estimating yield losses for agricultural crops

In Britain wheat is an important crop accounting for 41% of the total cereal production. In this study ozone concentrations for 1989 estimated as described in Part 1 of the paper are integrated with the estimated wheat distribution to derive a detailed estimate of the impact of ozone on wheat yields at a fine spatial scale (1km × 1km). These data provide estimates for calculating regional and national yield losses. The methodology can be applied to other crop species. Recent research on a range of crops has established relationships between the economic yield loss for certain crops, including wheat, and ozone exposure. Exposure is described as the accumulated exposure above a threshold experienced during the daylight hours (AOT). Critical AOT values are derived from yield exposure relationships which show linear reductions of yield loss with increasing ozone concentrations. This study has made use of land cover data from remotely sensed imagery at 25m resolution and nationally collected agricultural statistics for counties. These data were combined using an areal interpolation technique to provide more spatially articulate estimates of the location and intensity of wheat production. The results demonstrate the economic importance of ozone as a pollutant. Wheat yield losses attributed to ozone vary between different parts of the country but, for years when ozone levels are high, yield losses are likely to be significant in some areas.     

COLOR DOPPLER AND DOPPLER SPECTRAL ANALYSIS IN THE SPINAL CORD OF NORMAL DOGS

Doppler ultrasonography of the spinal cord was performed in 34 normal, anesthetized dogs following hemilaminectomy. This study was part of an investigation to evaluate the efficacy of a 21-aminosteroid compound and high dose methylprednisolone for the treatment of spinal cord trauma. Grey-scale images of the canine spinal cord were similar to those described for the spinal cord of people. Doppler waveforms of intraparenchymal spinal arteries exhibited high end diastolic blood flow velocities, indicating low resistance to flow. Doppler values (mean ± SD) for arteries immediately ventrolateral to the central canal were: Peak Systolic Velocity = 5.78 ± 2.5 cm/sec, Minimum Diastolic Velocity = 3.5 ± 1.62 cm/sec, Mean Velocity = 4.45 ± 1.96 cm/sec, Minimum Diastolic Velocity = 3.5 ± 1.62 cm/sec, Mean Velocity = 4.45 ± 1.96 cm/sec, Systolic/Diastolic ratio = 169 ± 0.19, Pulsatility Index = 0.53 ± 0.09, and Resistance Index = 0.4 ± 0.06.     

Incidence and significance of isolation of Mycoplasma felis from conjunctival swabs of cats

Conjunctival swabs taken from 40 cats with conjunctivitis and 65 cats without conjunctivitis were examined for the presence of Mycoplasma felis. The incidence of M. felis in cats with conjunctivitis was 25%. M. felis was not isolated from clinically normal cats. Inoculation of two isolates into the conjunctival sacs of healthy cats induced conjunctival hyperemia, starting 2-3 days after inoculation and disappearing without treatment within 7 days. It is concluded that M. felis plays a role in feline conjunctivitis.