Identification of small-scale low and high permeability layers using single well forced-gradient tracer tests: fluorescent dye imaging and modelling at the laboratory-scale.

Heterogeneity in aquifer permeability, which creates paths of varying mass flux and spatially complex contaminant plumes, can complicate the interpretation of contaminant fate and transport in groundwater. Identifying the location of high mass flux paths is critical for the reliable estimation of solute transport parameters and design of groundwater remediation schemes. Dipole flow tracer tests (DFTTs) and push-pull tests (PPTs) are single well forced-gradient tests which have been used at field-scale to estimate aquifer hydraulic and transport properties.

Fluorescent dye imaging of the volume sampled by single well forced-gradient tracer tests evaluated in a laboratory-scale aquifer physical model.

This study presents a new method to visualise forced-gradient tracer tests in 2-D using a laboratory-scale aquifer physical model. Experiments were designed to investigate the volume of aquifer sampled in vertical dipole flow tracer tests (DFTT) and push-pull tests (PPT), using a miniature monitoring well and straddle packer arrangement equipped with solute injection and recovery chambers. These tests have previously been used to estimate bulk aquifer hydraulic and transport properties for the evaluation of natural attenuation and other remediation approaches.

Cytotoxicity and antimicrobial activity of plants from New Zealand's subantarctic islands.

A total of 86 species of bryophytes, lichens and vascular plants were collected from New Zealand's subantarctic Campbell and Auckland Islands, including 18 subantarctic endemic species. Extracts of these species have been screened for antimicrobial activity and toxicity towards a P388 cell line. Of the main taxonomic groups collected, the proportion of extracts with some biological activity was highest for liverworts (25/29), intermediate for flowering plants (17/26) and lowest for mosses and horn worts (4/22).

Ovine ceroid-lipofuscinosis. I: Lipopigment composition is indicative of a lysosomal proteinosis.

The ceroid-lipofuscinoses are inherited lysosomal storage diseases of children and animals characterised by a fluorescent lipopigment stored in a variety of tissues. Defects in lipid metabolism or the control of lipid peroxidation have been postulated to explain their pathogenesis but the underlying biochemical defect is still unknown. In the present study lipopigment was isolated from liver, kidney, pancreas and brain of sheep affected with ceroid-lipofuscinosis.

The association of viruses with acute asthma.

The association of virus infection with an acute attack of asthma in 204 children admitted to hospital over a one year period was studied. Two comparative groups were assessed in parallel. Nineteen percent of acute asthma attacks were associated with viral infection.