Application of a novel phytotoxicity assay for the detection of herbicides in Hervey Bay and the Great Sandy Straits

A novel phytotoxicity assay was incorporated into an environmental assessment of Hervey Bay and the Great Sandy Straits, to investigate the role of run-off associated herbicides in the deteriorated health of intertidal seagrass meadows. Dose response curves of common herbicides were performed and their toxicity equivalents elucidated to assist in analysis. The results of the assay were reproducible and corresponded strongly with results of chemical analyses. The incorporation of the assay into the assessment of surface waters added an important aspect to the study by allowing investigation of the toxicity of cumulative herbicide concentrations and yielding biologically relevant data. The highest herbicide concentration detected during the study was equivalent to 0.23 microg l(-1) diuron; a concentration known to inhibit photosynthetic efficiency of the assay biomaterial by approximately 3%.     

The Diel Behaviour of Small Demersal Fish on Soft Sediments on the West Coast of Scotland using a Variety of Techniques: with Special Reference to Lesueurigobius friesii (Pisces; Gobiidae)

Abstract. The diel behaviour of communities of small demersal fishes was studied in situ on the west coast of Scotland using trawling, diving, underwater television and underwater time-lapse photography techniques. Lumpenus lampretaeformis and Pomatoschistus norvegicus were shown to have crepuscular behaviour patterns. Lesueurigobius friesii was a day active fish, spending the night close to or within its burrow and feeding through the day. Disruptions to this behaviour pattern occurred at high abundances of gadoids and during the spawning season. The fish community as a whole showed a crepuscular periodicity. The various observational methods are discussed. There did not appear to be any close association between Lesueurigobius friesii and the decapod Nephrops norvegicus.     

The proper motion VS redshift relation for superluminal radio sources

Two models for superluminal radio sources predict sharp lower bounds for the apparent velocities of separation. The light echo model predicts a minimum velocityv _min=2c, and the dipole field model predictsv _min=4.446c. Yahil (1979) has suggested that, if either of these models is correct, thenv _min provides a standard velocity which can be used to determine the cosmological parametersH andq ₀. This is accomplished by estimating a lower envelope for the proper motion vs redshift relation. Yahil also argued that the procedure could easily be generalized to include a nonzero cosmical constant . We derive the formulas relating the proper motion to the redshiftz in a Friedmann universe with a nonzero . We show that the determination of a lower envelope for a given sample of measured points yields an estimate of the angle of inclination _i for each source in the sample. We formulate the estimation of the lower envelope as a constrained maximum likelihood problem with the constraints specified by the expected value of the largest order statistic for the estimated _i . We solve this problem numerically using an off-the-shelf nonlinearly constrained nonlinear optimization program from the NAg library. Assuming =0, we apply the estimation procedure to a sample of 27 sources with measured values , using both the light echo and the dipole field models. The fits giveH=103 km s^–1 Mpc^–1 for the light echo model andH=46 km s^–1 Mpc^–1 for the dipole field model. In both cases the fits giveq ₀=0.4, but the uncertainty in this result is too large to rule out the possibility thatq ₀>0.5. When is allowed to be a free parameter, we obtainH=105 km s^–1 Mpc^–1 for the light echo model andH=47 km s^–1 Mpc^–1 for the dipole field model. In both cases the fits giveq ₀=–1 and /H ₀ ² =6.7, but no significance can be attached to these results because of the paucity of measured data at hight redshifts. For all of the fits, we compute the corresponding estimates of the _i and compare the cumulative distribution of these values with that expected from a sample of randomly oriented sources. In all cases we find a large excess of sources at low-inclination angles (high apparent velocities). The expected selection effect would produce such an excess, but the excess is large enough to suggest a strong contamination of the sample by relativistic beam sources which would only be seen at low inclination angles.Applied Research Corporation     

Cytochrome P450 isozyme protein verified in the skin of southern hemisphere humpback whales (Megaptera novaeangliae): implications for biochemical biomarker assessment

Large mysticete whales represent a unique challenge for chemical risk assessment. Few epidemiological investigations are possible due to the low incidence of adult stranding events. Similarly their often extreme life-history adaptations of prolonged migration and fasting challenge exposure assumptions. Molecular biomarkers offer the potential to complement information yielded through tissue chemical analysis, as well as providing evidence of a molecular response to chemical exposure. In this study we confirm the presence of cytochrome P450 reductase (CPR) and cytochrome P450 isoenzyme 1A1 (CYP1A1) in epidermal tissue of southern hemisphere humpback whales (Megaptera novaeangliae). The detection of CYP1A1 in the integument of the humpback whale affords the opportunity for further quantitative non-destructive investigations of enzyme activity as a function of chemical stress.     

Documentary evidence of climate variability during cold seasons in Lesotho, southern Africa, 1833–1900

This study presents the first 19th century cold season climate chronology for the Kingdom of Lesotho in southern Africa. The chronology is constructed using a variety of documentary sources including letters, diaries, reports, monographs and newspaper articles obtained from southern African and British archives. Information relating to cold season weather phenomena during the austral autumn, winter and early spring months were recorded verbatim. Each of the cold seasons from 1833 to 1900 was then classified as “very severe”, “severe” or “normal/mild”, with a confidence rating ranging from low (1) to high (3) awarded against each annual classification. The accuracy of the document-derived chronology was verified against temperature data for Maseru for the period 1893–1900. Excellent correspondence of the document-derived chronology with the Maseru instrumental data and also with other global proxy temperature records for the 19th century is achieved. The results indicate 12 (18% of the total) very severe, 16 (23%) severe and 40 (59%) normal/mild cold seasons between 1833 and 1900. The overall trend is for more severe and snow-rich cold seasons during the early part of the study period (1833–1854) compared with the latter half of the 19th century (with the exception of the 1880s). A reduction in the duration of the frost season by over 20 days during the 19th century is also tentatively identified. Several severe to very severe cold seasons in Lesotho follow after major tropical and SH volcanic eruptions; such years are usually characterized by early frosts, and frequent and heavy snowfalls. The blocking of solar radiation and the enhanced northward displacement of polar fronts that are directly or indirectly associated with volcanic events, may account for many of the most severe Lesotho winters during the 19th century.