Search

Mining has occurred at the Hercules Ag, Au, Cu, Pb, Zn VHMS deposit in western Tasmania, almost continuously for the last I 00 years. Mining activity has degraded the local environment, through clearing of vegetation, enhanced erosion and the formation of acid mine drainage (AMD). Of significant concern is the Bakers Creek waste rock dump, situated in a waterfall in the upper reaches of Bakers Creek. This steep, unstable sulfidic rock pile cannot be readily removed or engineered, and is an on-going source of AMD. To allow rehabilitation options for the waste rock dump to be devised, the contribution of AMD from the Bakers Creek waste rock dump needed to be ascertained. Long term and intensive water sampling programs have been implemented to characterise and quantify AMD emanating from the waste rock dump, and to investigate climatic controls on water quality of Bakers Creek. Water samples were collected from ten sites along Bakers Creek, where field analyses of pH, Eh, conductivity and temperature were conducted. Water samples were collected for laboratory analyses of major and trace element concentrations, sulphate, chloride and alkalinity. The pH of the drainage waters vary from 5.6 (upstream of mining activity) to 3.0 (foot of the waste rock dump). Maximum metal concentrations were measured at the adit, or the base of the waste rock dump. Major contaminants are Fe (43.8ppm), Pb (19.2ppm), AI (8.47ppm) and Sulfate (1440ppm) and Zn (82.2ppm). During base flow, approximately 47.6 T/yr of Zn is discharging from Bakers Creek into Ring River, (98% of which is contributed by the waste rock dump). Other contaminants contributed by the waste rock dump, represented at least 95% of the total contamination in Bakers Creek including AI (2.87 T/yr), Cu (0.77 T/yr), Fe (1.54 T/yr), Pb 1.9 T/yr, and Sulfate, (199T/yr). The maximum mass loads were recorded during storm events (measured at the base of Bakers Creek). The maximum mass load for each contaminant was 158.9 T/yr Zn, 13.9 T/yr AI, 0.33 T/yr Cd, 3.95 T/yr Cu, 65.4 T/yr Fe, 56.15 T/yr Mn, 23.75 Pb T/yr, and 756 T/yr sulphate. These metal mass loads are high enough to consider metal recovery strategies. To remediate Bakers Creek, a combination of treatment strategies are probably required. Diversion of Bakers Creek upstream of the waste rock dump, combined with the installation of a biosulphide metal recovery plant to treat Zn, have potential to reduce metal and sulphate concentrations to acceptable levels, and to increase pH. A major advantage would be the metals can be extracted from solution and sold to create revenue to offset costs incurred from installing and operating the plant. Diversion of Bakers Creek combined with a wetland filter system at Williamsford, could be an alternative remediation strategy if a biosulphide treatment is not viable.

Absence from work costs American companies more than $40 billion annually. Absenteeism control programs can be cost effective, but relatively few companies in the U.S. seem to have comprehensive programs. Key elements in a comprehensive program include return to work opportunities, careful job design, standards for expected times off, clear administrative responsibility for communicating with absent employees and health care providers, and an effective information system. Perhaps the most important factor in a successful program is employee centered management and a corporate philosophy that views employees as assets. The occupational health nurse is ideally suited by education, knowledge, and job function to lead the design and management of a comprehensive absenteeism control program.

Amplification of viral DNA offers a potentially sensitive and specific method for identifying herpes viruses in pathologic specimens. The purpose of this study is to assess the value of polymerase chain reaction amplification of DNA as a diagnostic test for herpes virus in pathologic specimens. The purpose of this study is to assess for herpes virus infections. We examined 79 paraffin-embedded tissue samples from 43 patients and 55 viral culture samples from 45 patients. Herpes virus DNA in the specimens was amplified by polymerase chain reaction. Using paraffin-embedded tissue on which a diagnosis of herpes virus was made by morphologic criteria, 11 of 19 patients had herpes virus DNA identified by PCR; herpes virus DNA was not identified in any of 35 negative control specimens. Herpes virus DNA was also identified by polymerase chain reaction in all of the positive herpes virus culture specimens. Of 29 culture negative specimens, herpes virus DNA was identified in six. We conclude that polymerase chain reaction is useful to establish or confirm the presence of a herpes virus infection in paraffin-embedded tissue samples and that it is more sensitive than viral culture.

The Stone bunionectomy is an oblique resection of the metatarsal head designed to preserve the weight-bearing margin of the metatarsal shaft. In 132 patients treated by the Stone operation, only 77 per cent were satisfied with the overall results and 19 per cent had persistent pain. In addition, only 69 per cent were considered by the authors to have had an excellent result. These results do not compare favorably with those reported for the Keller procedure. Consequently, the Stone bunionectomy is not recommended.

Les parametres pharmacocinetiques des medicaments sont tres comparables, chacun presentant une biodisponibilite elevee et d'autres facteurs comme le prix de revient peut etre des facteurs plus importants de l'utilisation des thioamides

purpose. To compare visual and pupil afferent function in dominant optic atrophy (DOA). \ud \ud methods. Patients with DOA who belonged to families showing evidence of linkage to the locus on chromosome 3q28-qter were recruited from the Moorfields Genetic Register. Patients and healthy control subjects underwent visual and pupil perimetry using a modified automated perimeter (Octopus 1-2-3; Interzeag, Schlieren, Switzerland). Five stimulus locations were tested: fixation, and at 17° eccentricity along the 45° and 135° meridians in all four quadrants. The visual deficit (difference in decibels between the patient’s luminance threshold and that in age-matched healthy control subjects) was compared directly with the pupil deficit (difference in decibels between the stimulus intensity giving the patient’s pupil response and that giving an equivalent pupil response in healthy control subjects) at each test location. \ud \ud results. Visual deficits and pupil afferent deficits were found at all five locations. The visual deficits were significantly greater than the pupil deficits at the four peripheral locations (median difference = 6.3 dB, P < 0.001). At fixation, the difference was not significant (median difference = 2.3 dB, P = 0.407). \ud \ud conclusions. Pupil function appears less affected than visual function at four of five locations tested. This result provides evidence that the retinotectal fibers serving the pupil light reflex are less susceptible to damage from the OPA1 genetic defect than the retinogeniculate fibers serving vision.