Aquatic turtles of Amazonia: An endangered resource

Turtles have long served man as an important food resource in Amazonia. During the colonial period, Portuguese traders disturbed nesting beaches on a large scale in search of eggs which were converted into oil for cooking and lighting. Exploitation was increasingly intense by the end of the 19th century and turtle populations had declined drastically. Although legislation has been passed to protect them, enforcement is lax and turtles face increasing pressure from man not only for food but as a result of habitat disturbance.     

The Prince Edward Islands: A sanctuary for seabirds in the Southern Ocean

This paper reviews the breeding distribution and numerical status of selected species of seabirds at 23 oceanic island groups in the Southern Ocean (between latitudes 35 and 70°S), based on census data and population estimates which have become available through increased scientific endeavour in the region during the last 15 years or so. The paper focuses on the avifauna of the Prince Edward islands, in the southern Indian Ocean, and points to the importance of these islands as a breeding station and sanctuary for seabirds. Only one oceanic island group, the Crozets, contains more species of breeding seabirds than the Prince Edward islands. Substantial segements (about 10% and greater) of the world breeding populations of the king and macaroni penguins, and the wandering, grey-headed, yellow-nosed and sooty albatrosses are based at the Prince Edward group. We recommend that Prince Edward Island (sensu stricto) should be a wilderness area, and that development at Marion Island should be kept to an absolute minimum.     

Proposals for a Sangay National Park in Ecuador

This paper describes the main features of the Sangay wilderness area in the Ecuadorian Andes. It is a region of great diversity with life zones ranging from tundra to subtropical rain forest. The conservation value of the area is assessed and the feasibility of protection determined. Boundaries based mainly on the limits of human interference are put forward with management proposals for its establishment as a National Park.     

Effects of repeated use of an area of heather Calluna vulgaris (L.) hull moor at Kindrogan,Scotland, for teaching purposes

A triangular plot of heather moor at Kindrogan was used for teaching botanical analysis for eight years, using the same set of random coordinates to locate sample points. Because of the method of point location, there was a gradient of trampling pressure across the plot, and there were also parts of the plot that were never analysed. At the end of the eight-year period heather cover and mean height were found to have declined with increasing levels of trampling. Mean numbers of species/m² did not however decline, and were actually minimal on untrampled ground. With moderate levels of trampling, quadrats that had been analysed for eight years contained more heather litter than those that had not been analysed before. No decline in species frequencies was found in previously analysed quadrats. The value of the plot for teaching purposes does not seem to have declined, and may have actually increased over the period of use.     

Overview and status of in vitro transformation.

The development of standardized assay procedures has permitted the exploitation of cell culture systems as bioassay tools for the detection of chemical carcinogens. These systems fall generally into 3 classes: diploid cell strains, Syrian hamster embryo cells; cell lines, mouse BALB/c-3T3 and mouse C3H-10T1/2; and cells+virus, Fischer rat cells infected with Rauscher leukemia virus and Syrian hamster embryo cells infected with adenovirus. The results accumulated to date show a good correlation between transformation response in cell culture and carcinogenicity of chemicals in whole animal studies. The major advantages of these systems are their relative brevity (10 days-6 weeks) and resultant low costs, their agreement with whole animal bioassays, and their direct biological relevance to the carcinogenic process. The present major disadvantages are the uncertain nature of the metabolic capabilities of the target cells and the lack of a metabolic activation system that is reliable and adaptable for routine bioassays. The development of epithelial cell systems such as breast, liver, lung, and skin may solve the problem of carcinogen metabolism as well as provide target cells that are representative of major organ sites for cancer in man. The rational use of cell culture bioassays for neoplastic transformation is a valuable component of the toxicological armamentarium to assess risk to humans from exposure to chemicals.     

Spectrophotometric analysis of binary mixtures of sulfonamides.

Different methods for analyzing binary mixtures by using 2 wavelengths are reviewed. The absorbance ratio calculated at 2 wavelengths, not including the isoabsorptive point, was a quadratic function of relative concentration. The curve-fitting process using orthogonal polynomials was applied to obtain the quadratic equation. An absorbance ratio can be used as a rapid purity index for sulfacetamide sodium in the presence of sulfanilamide. Sulfacetamide sodium has been determined in eye drop preparations.     

The effects of the severe drought of 1976 on the vegetation of some moorland pools in The Netherlands

The effect of the extreme drough of 1976 has been studied to obtain information on the reaction of the vegetation of moorland pools following a fall in the ground water level. The degree of change appeared to be dependent on the nutrient status of water and soil and on the relief. The vegetation of metatrophic and guanotrophic moorland pools showed the most drastic change.     

Effect of strains of Rhizobium trifolii on the establishment of oversown white clover (Trifolium repens)

Strains of Rhizobium trifolii incorporated into commercial peat inoculants were compared for their effect on the establishment and growth of oversown white clover (Trifolium repens) on soils devoid of infective rhizobia.There were marked differences in numbers of seedlings establishing and clover dry matter production per hectare with the various strains. However, when adjusted to a constant number of established seedlings, dry matter production from all strains, apart from one strain at one site, were similar indicating that the strains did not appear to influence the growth of individual clover plants.The marked differences in establishment of clover inoculated with the various strains could not be accounted for by differences in the number of rhizobia in the peat inoculant.Selecting strains of rhizobia for ability to increase establishment is considered important where clover is oversown onto soils devoid of rhizobia.     

A comparison of methods of recovering oesophageal extrusa from grazing sheep

Extrusa samples were collected from two groups of oesophageally fistulated sheep grazing together. One group had foam plastic oesophageal plugs fitted below the fistula to assist in the complete collection of extrusa; the second group grazed without plugs. The extrusa were collected in four periods chosen to cover as wide a range of herbage conditions as possible varying from herbage with a high proportion of green leaves to predominantly dry material with a high proportion of dead leaves and stems. The plant components of the extrusa were determined and there was no evidence that stems or any other plant component preferentially by-pass the fistula in grazing sheep. It was concluded that it is not necessary to insert foam plastic plugs in the oesophagus of grazing sheep to obtain representative samples of ingested herbage.