Bridging a biogeographic 'gap' : microfossil evidence for the quillwort Isoetes on the Cumberland Plain west of Sydney during the early Colonial period

Fossil spores preserved on historical archaeological sites at Parramatta and Richmond indicate that two or more species of the quillwort genus Isoetes (family Isoetaceae) were growing along rivers on the Cumberland Plain, west of Sydney, during the late 18th and early 19th centuries. Perispore ornamentation indicates the parent plants were related to Isoetes drummondii A.Braun and Isoetes muelleri A.Braun: A possible third species produced microspores that are similar to, but much larger than, the spores produced by modern Isoetes muelleri. Apart from one dubious record, Isoetes has not been found in the Sydney flora or on the New South Wales Central Coast and Central Tablelands botanical subdivisions, but does occur in the Central Western Slopes, and botanical subdivisions to the north of Sydney (North Coast, Northern Tablelands) and south (Southern Tablelands, South-Western Slopes, South-Western Plains), as well as in other States. Our data indicate the present day disjunct distribution of Isoetes in New South Wales is most likely to be due to European settlement. The ability of quillworts to survive moderate levels of disturbance during the early Colonial period raises the possibility that remnant populations may still survive in protected areas on the Cumberland Plain

Two Poems

Poetry by Carlyle MacPhai

Data Retransmission via Satellites

There are no author-identified significant results in this report

Successive Induction in Larval Zebrafish

Activating one reflex often facilitates another, antagonistic one. Since Charles Sherrington first identified successive induction more than 100 years ago, it has been demonstrated in a wide range of species, from aphids to grasshoppers to dogs and humans. We show a particularly orderly example in zebrafish (Danio rerio) larvae and identify the simple dynamic process that seems to underlie it

K-Ar dated palynofloras in Tasmania 1: Early Oligocene, Proteacidites tuberculatus Zone sediments, Wilmot Dam, northwestern Tasmania

Tertiaty lake sediments at Wilmot Dam, northwestern Tasmania, are dated as Lower Proteacidites tuberculatus Zone, based on the palynological zonation developed for the Gippsland Basin in eastern Bass Strait. The age limits of Early-Middle Oligocene for this zone are in excellent agreement with a K/Ar date of 26.7 Ma for basalts capping this deposit. Three new species are described: Tricolpites stylidioides, Mutisiapollis patersonii and Periporopollenites hexaporus. The first two appear to be the earliest records to date of Stylidiaceae and Mutisia (Asteraceae:tribe Mutisieae) respectively

Labour Migration and Time Use Patterns of the Left-Behind Children and Elderly in Rural China

Rural-urban migration has become a major feature of the Chinese economy since the mid-1990s. Due to institutional arrangements and economic and cultural factors, massive labor migration has resulted in a large left-behind population consisting of children, non-elderly married women, and the elderly. This paper examines the impacts of labor migration on time use patterns of the left-behind elderly people and children in rural China, using data derived from the China’s health and Nutrition Health Survey (CHNS) for the period between 1997 and 2006. The results show that the migration of household members increases the time spent on farm work and domestic work for the left-behind elderly, and the migration of parents increases the time spent on farm work and domestic work for the left-behind children. Importantly, migration has striking gender differentiated impacts with the increase in work time being greater for elderly women and girls than elderly men and boys. These results have important policy implications.

Analysis of radiation-induced bystander effects using high content screening

When cells are exposed to (ionising) radiation there is a rapid phosphorylation of a minor nucleosomal histone protein, H2AX, at the sites where double stranded breaks (DSB) occur. This phosphorylation is one of the earliest events in the repair cascade and extends over several mega base pairs surrounding the break. Nowadays it is generally accepted that the formation of γH2AX functions as a signal enhancer. Using immuno histochemistry we can visualise this phosphorylation as foci in the nucleus, where each foci represents a DSB [1]. For our research we use normal human primary fibroblasts (NHDF’s) to study the so called radiation-induced bystander effects which refer to the responses induced in non-irradiated cells, when neighbouring cells are irradiated. Although the exact pathways of transmission are yet to be determined, studies have shown that gap junction-mediated transport and secretion of soluble extracellular factors play an important role [2]. To exclude variation we first tried synchronisation of the fibroblasts using nocodazole or aphidicolin. Our attempts did not produce the desired synchronisation level. In addition, recent reports doubt the effectiveness of these products in cell synchronisation [3]. To resolve this problem, we used high content screening of cells together with specific cell cycle markers. One of these markers is 5-bromo-2-deoxyuridine (BrdU). BrdU, a synthetic nucleoside, is an analogue of thymidine that can be incorporated in replicating cells and specifically label S-phases [4]. Cells are cultured on membrane inserts, with a pore size of 0,4µm allowing soluble factors to pass but preventing the cells to interchange. These cells are irradiated with different doses and subsequently placed together with NHDF that are grown on cover glasses (see figure 1). Depending on the objectives BrdU is added 20-40 minutes before fixation. We found a differential pattern for γH2AX that we could specifically link to the cell cycle. During the S phase γH2AX is significantly more induced than during other phases of the cell cycle (see figure 2). This is probably due to the increased vulnerability caused by the unwinding of DNA during replication. 1. ¬¬S.H.Macphail, J.P.Banath, T.Y.Yu, E.H.Chu, H.Lambur, P.L.Olive, Int.J.Radiat.Biol. 79 (2003) P. 351-358. 2. H.Yang, N.Asaad, K.D.Held, Oncogene 24 (2005) p. 2096-2103. 3. S.Cooper, G.Iyer, M.Tarquini, P.Bissett, Cell Tissue Res. 324 (2006) p.237-242. 4. R.T.O'Keefe, S.C.Henderson, D.L.Spector, J.Cell Biol. 116 (1992) p.1095-1110

A fossil bolster plant from the King River, Tasmania

A macrofossil of the alpine bolster plant Donatia novae-zelandiae was found in the King River Valley, approximately 230 m above sea level in central western Tasmania. The fossil was in situ on a palaeosol that appears to have formed immediately prior to the late Last Glacial Maximum. An age of 21 180 + 370 years b.p. was established by radiocarbon dating. Pollen and present day distributional data suggest that the tree line was then at least 750 m lower than at present, implying a temperature depression of about 4.5 0 C. Scanning electron-micrographs and photomicrographs of the extant and fossil bolster species are presented

Relative risk of HIV infection among young men and women in a South African township

The prevalence of HIV infection in Africa is substantially higher among young women than it is among young men. Biological explanations of this difference have been presented but there has been little exploration of social factors. In this paper we use data from Carletonville, South Africa to explore various social explanations for greater female infection rates. This paper reports on data from a random sample of 507 people between 13 and 24 years old. Subjects were tested for HIV, as well as other sexually transmitted infections (STIs), and answered a behavioural questionnaire. The age-prevalence of HIV infection differs between men and women with considerably higher rates of increase with age among young women. The age of sexual debut did not differ significantly between men and women (15.9 and 16.3 years, respectively) and below the age of 20 years there was no difference in the number or distribution of the number of sexual partners reported by men or women. The risk of infection per partnership was substantially higher among women than among men. Women have sexual partners who are, on average, about five years older than they are with some variation with age. Scaling the age-prevalence curve for men by the age of their sexual partners gives a curve whose shape is indistinguishable from that for women but is about 30% lower for men than for women. In terms of social explanations for HIV rates among women, the data indicates that this difference can be explained by the relative age of sexual partners, but not by other factors explored. In addressing the epidemic among young women it will be essential to deal with the social factors that lead young women to select their partners from older-age cohorts and that shape their sexual networking patterns