A High Statistics Search for Ultra-High Energy Gamma-Ray Emission from Cygnus X-3 and Hercules X-1

We have carried out a high statistics (2 Billion events) search for ultra-high energy gamma-ray emission from the X-ray binary sources Cygnus X-3 and Hercules X-1. Using data taken with the CASA-MIA detector over a five year period (1990-1995), we find no evidence for steady emission from either source at energies above 115 TeV. The derived upper limits on such emission are more than two orders of magnitude lower than earlier claimed detections. We also find no evidence for neutral particle or gamma-ray emission from either source on time scales of one day and 0.5 hr. For Cygnus X-3, there is no evidence for emission correlated with the 4.8 hr X-ray periodicity or with the occurrence of large radio flares. Unless one postulates that these sources were very active earlier and are now dormant, the limits presented here put into question the earlier results, and highlight the difficulties that possible future experiments will have in detecting gamma-ray signals at ultra-high energies.Comment: 26 LaTeX pages, 16 PostScript figures, uses psfig.sty to be published in Physical Review

Perspectives of a nurse, a social-worker and a psychiatrist, regarding patient assessment in acute inpatient psychiatry settings : a case study approach

This case study explores what informs and organizes the assessment of patients, as undertaken by a nurse, a social worker and a psychiatrist in public, metropolitan, acute mental health service settings. The research data are the transcripts of in-depth interviews with three experienced practitioners, one from each of the three disciplines. The analysis draws on Foucauldian concepts: discourse as constructed through practices of discipline and the gaze. We explored examples of taken-for-granted assessment practices and their interplay with discourse. The findings suggest that participating practitioners use language in assessment in ways that support the powerful discourses of the professional disciplines. The competing discourse of management, associated with industry and economics, is evident in hospital admission processes, dictating the times and places of assessment. Professional and management discourses both effectively marginalize the perspective of another player in assessment, the patient.<br /

Gonococcal Lipooligosaccharide is a ligand for the asialoglycoprotein receptor in human sperm

In the present study, we show that Neisseria gonorrhoeae lipooligosaccharide (LOS) can bind to the asialoglycoprotein receptor (ASGP-R) on human sperm. This work demonstrates the presence of ASGP-R on human sperm. Binding of purified ASGP-R ligand decreased in the presence of gonococci. Binding of purified iodinated gonococcal LOS identified a protein of molecular weight corresponding to that of human ASGP-R. The presence of excess unlabelled LOS blocked binding of iodinated gonococcal LOS. Binding of wild-type gonococcal LOS to sperm was higher than that of mutant LOS lacking the galactose ligand for ASGP-R. These data suggest that the ASGP-R on human sperm cells recognizes and binds wild-type gonococcal LOS. This interaction may contribute to the transmission of gonorrhea from infected males to their sexual partners