Cenozoic continental weathering and its implications for the palaeoclimate: evidence from Ar-40/Ar-39 geochronology of supergene K-Mn oxides in Mt Tabor, central Queensland, Australia

One hundred and twenty-five mineral grains from 45 visually pure K-bearing Mn oxide (hollandite group) samples collected from weathering profiles in the Mt Tabor region of central Queensland, Australia, were analysed by the Ar-40/Ar-39 laser probe technique. These K-Mn oxides precipitated mainly through a process of cavity filling (direct precipitation from weathering solution), with botryoidal texture formed by micrometric mineral bands. Well-defined and reproducible plateau ages have been obtained for most samples, ranging from 27.2 +/- 0.8 to 6.8 +/- 0.5 Ma (2 sigma). Statistical analysis of the geochronological results by mixture modelling suggests an episodic mineral precipitation history, with two major peaks at 20.2 +/- 0.22 Ma and 16.5 +/- 0.17 Ma. The geochronological results, when combined with information on paragenetic relationships and mineralogical textures obtained from petrographic, scanning electron microscopy, and electron microprobe investigations, indicate that warm and humid palaeoclimatic conditions favourable to intense chemical weathering prevailed in central Queensland from late Oligocene to middle Miocene, particularly in the early Miocene. These results, in conjunction with previous and ongoing investigations in NW and eastern Queensland, suggest that most of Queensland was dominated by humid climates during the Miocene. (C) 2002 Elsevier Science BN. All rights reserved.

Lepocreadiinae lepocreadiids (Digenea) from tetraodontiform fishes in the waters off Tasmania, Queensland and Moorea, French Polynesia

Two new species of Pseudocreadium are described from off northern Tasmania, P maturini sp. nov. from Meuschenia freycineti and P aubreyi sp. nov. from Acanthaluteres vittiger. They differ from the only other recognised species in the genus by the number of ovarian lobes and by size, and they differ from each other by size, shape, caecal length, forebody length, pre-oral lobe size, uterine position, excretory vesicle length and oral sucker shape. Lobatocreadium exiguum is redescribed from Sufflamen bursa, off Moorea, French Polynesia and Abalistes stellatus, Swain Reefs, Great Barrier Reef, Queensland. Records and measurements are given for Hypocreadium cavum from Sufflamen fraenatus and Lepotrema clavatum from Melichthys vidua, both off Heron Island, Great Barrier Reef, Queensland.

Kainic acid induces 14-3-3 zeta expression in distinct regions of rat brain

Areas of the limbic system of adult male Wistar rats were screened for kainic-acid-induced gene expression. Polymerase-chain-reactionbased differential display identified a 147-bp cDNA fragment, which represented an mRNA that was upregulated in the entorhinal cortex and hippocampus in the kainic-acid-treated animals. The sequence was 97.8% homologous to rat 14-3-3 zeta isoform mRNA. Detailed Northern analysis revealed increased mRNA levels in the entorhinal cortex I h after kainic acid exposure and continued elevation 24 h post-injection in both the entorhinal cortex and hippocampus. Western blot analyses confirmed that the protein product of this gene was also present in increased amounts over the same time period. Immunohistochemistry and terminal transferase-mediated dUTP nick end labelling (TUNEL) detected expression of 14-3-3 protein exclusively in the entorhinal cortex and hippocampus, and only in TUNEL-positive neuronal cells. Expression of the tumor suppressor protein, p53 was also induced by kainate injection, and was co-localized with 14-3-3 zeta protein in selected cells only in the affected brain regions. The increase gene expression of 14-3-3 represents a transcription-mediated response associated with region selective neuronal damage induced by kainic acid. (C) 2002 Elsevier Science B.V. All rights reserved.

Marine and estuarine reservoir effects in central Queensland, Australia: Determination of Delta R values

As a component of archaeological investigations on the central Queensland coast, a series of five marine shell specimens live-collected between A.D. 1904 and A.D. 1929 and 11 shell/ charcoal paired samples from archaeological contexts were radiocarbon dated to determine local DeltaR values. The object of the study was to assess the potential influence of localized variation in marine reservoir effect in accurately determining the age of marine and estuarine shell from archaeological deposits in the area. Results indicate that the routinely applied DeltaR value of -5 +/- 35 for northeast Australia is erroneously calculated. The determined values suggest a minor revision to Reimer and Reimer's (2000) recommended value for northeast Australia from DeltaR = +11 +/- 5 to + 12 +/- 7, and specifically for central Queensland to DeltaR = +10 +/- 7, for near-shore open marine environments. In contrast, data obtained from estuarine shell/charcoal pairs demonstrate a general lack of consistency, suggesting estuary-specific patterns of variation in terrestrial carbon input and exchange with the open ocean. Preliminary data indicate that in some estuaries, at some time periods, a DeltaR value of more than - 155 +/- 55 may be appropriate, In estuarine contexts in central Queensland, a localized estuary-specific correction factor is recommended to account for geographical and temporal variation in C-14 activity. (C) 2002 Wiley Periodicals.