2 research outputs found

    High-Velocity clouds in the galactic all sky survey. i. catalog

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    We present a catalog of high-velocity clouds (HVCs) from the Galactic All Sky Survey (GASS) of southern sky neutral hydrogen, which has 57 mK sensitivity and 1 km s-1 velocity resolution and was obtained with the Parkes Telescope. Our catalog has been derived from the stray-radiation-corrected second release of GASS. We describe the data and our method of identifying HVCs and analyze the overall properties of the GASS population. We catalog a total of 1693 HVCs at declinations <0°, including 1111 positive velocity HVCs and 582 negative velocity HVCs. Our catalog also includes 295 anomalous velocity clouds (AVCs). The cloud line-widths of our HVC population have a median FWHM of ∼19 km s-1, which is lower than that found in previous surveys. The completeness of our catalog is above 95% based on comparison with the HIPASS catalog of HVCs upon which we improve by an order of magnitude in spectral resolution. We find 758 new HVCs and AVCs with no HIPASS counterpart. The GASS catalog will shed unprecedented light on the distribution and kinematic structure of southern sky HVCs, as well as delve further into the cloud populations that make up the anomalous velocity gas of the Milky Wa

    Investigations on the diagnosis and retroviral aetiology of renal neoplasia in budgerigars (Melopsittacus undulatus)

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    The high susceptibility of budgerigars (Melopsittacus undulatus) to neoplasia, and specifically renal neoplasia, has often been reported. Further investigations led to a suspicion of a retrovirus as the causative agent for renal neoplasia in budgerigars, but definitive proof has yet to be found. In the present study, 32 budgerigars suspected of having renal neoplasia (based on the clinical presentation) were examined. The objectives were to investigate the use of different diagnostic methods for the ante-mortem diagnosis of this condition and to find more supporting evidence of a retroviral aetiology. The predominant clinical signs observed in budgerigars with renal neoplasia were lameness and absence of deep pain sensation of one leg. Alterations in haematology, plasma chemistry, and urine analyses could not pinpoint the cases of renal neoplasia. Contrast radiography of the intestinal tract proved to be diagnostically more useful compared with plain radiographic studies. Histology confirmed the renal neoplasia as adenocarcinoma. Investigations for virus identification included product-enhanced reverse transcriptase assay and enzyme-linked immunosorbent assay for the detection of avian leucosis virus group-specific antigen. Cell cultures and electron microscopy were performed on a limited number of patients. These investigations could find no presence of an exogenous, replicating retrovirus, neither could viral particles be detected by electron microscopy. Based on the current findings, it can be concluded that there is no evidence of retroviral involvement in the occurrence of renal neoplasia in budgerigars
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