Ecosystem process models at multiple scales for mapping tropical forest productivity

Quantifying mass and energy exchanges within tropical forests is essential for understanding their role in the global carbon budget and how they will respond to perturbations in climate. This study reviews ecosystem process models designed to predict the growth and productivity of temperate and tropical forest ecosystems. Temperate forest models were included because of the minimal number of tropical forest models. The review provides a multiscale assessment enabling potential users to select a model suited to the scale and type of information they require in tropical forests. Process models are reviewed in relation to their input and output parameters, minimum spatial and temporal units of operation, maximum spatial extent and time period of application for each organization level of modelling. Organizational levels included leaf-tree, plot-stand, regional and ecosystem levels, with model complexity decreasing as the time-step and spatial extent of model operation increases. All ecosystem models are simplified versions of reality and are typically aspatial. Remotely sensed data sets and derived products may be used to initialize, drive and validate ecosystem process models. At the simplest level, remotely sensed data are used to delimit location, extent and changes over time of vegetation communities. At a more advanced level, remotely sensed data products have been used to estimate key structural and biophysical properties associated with ecosystem processes in tropical and temperate forests. Combining ecological models and image data enables the development of carbon accounting systems that will contribute to understanding greenhouse gas budgets at biome and global scales.

Radiation of the Australian flora: What can comparisons of molecular phylogenies across multiple taxa tell us about the evolution of diversity in present-day communities?

The Australian fossil record shows that from ca. 25 Myr ago, the aseasonal-wet biome (rainforest and wet heath) gave way to the unique Australian sclerophyll biomes dominated by eucalypts, acacias and casuarinas. This transition coincided with tectonic isolation of Australia, leading to cooler, drier, more seasonal climates. From 3 Myr ago, aridification caused rapid opening of the central Australian and zone. Molecular phylogenies with dated nodes have provided new perspectives on how these events could have affected the evolution of the Australian flora. During the Mid-Cenozoic (25-10 Myr ago) period of climatic change, there were rapid radiations in sclerophyll taxa, such as Banksia, eucalypts, pea-flowered legumes and Allocasuarina. At the same time, taxa restricted to the aseasonal-wet biome (Nothofagus, Podocarpaceae and Araucariaceae) did not radiate or were depleted by extinction. During the Pliocene aridification, two Eremean biome taxa (Lepidium and Chenopodiaceae) radiated rapidly after dispersing into Australia from overseas. It is clear that the biomes have different histories. Lineages in the aseasonal-wet biome are species poor, with sister taxa that are species rich, either outside Australia or in the sclerophyll biomes. In conjunction with the fossil record, this indicates depletion of the Australian aseasonal-wet biome from the Mid-Cenozoic. In the sclerophyll biomes, there have been multiple exchanges between the southwest and southeast, rather than single large endemic radiations after a vicariance event. There is need for rigorous molecular phylogenetic studies so that additional questions can be addressed, such as how interactions between biomes may have driven the speciation process during radiations. New studies should include the hither-to neglected monsoonal tropics.

The gall-inducing habit has evolved multiple times among the eriococcid scale insects (Sternorrhyncha : Coccoidea : Eriococcidae)

The habit of inducing plant galls has evolved multiple times among insects but most species diversity occurs in only a few groups, such as gall midges and gall wasps. This phylogenetic clustering may reflect adaptive radiations in insect groups in which the trait has evolved. Alternatively, multiple independent origins of galling may suggest a selective advantage to the habit. We use DNA sequence data to examine the origins of galling among the most speciose group of gall-inducing scale insects, the eriococcids. We determine that the galling habit has evolved multiple times, including four times in Australian taxa, suggesting that there has been a selective advantage to galling in Australia. Additionally, although most gall-inducing eriococcid species occur on Myrtaceae, we found that lineages feeding on Myrtaceae are no more likely to have evolved the galling habit than those feeding on other plant groups. However, most gall-inducing species-richness is clustered in only two clades (Apiomorpha and Lachnodius + Opisthoscelis), all of which occur exclusively on Eucalyptus s.s. The Eriococcidae and the large genus Eriococcus were determined to be non-monophyletic and each will require revision. (C) 2004 The Linnean Society of London.

The role of CD4 T help in multiple vaccinations when using minimal CD8 T cell epitope peptides

Background: The fact that some cancers and viral infections can be controlled by effector CD8 T cells led to the possibility of utilising minimal CD8 T cell epitope peptides as vaccines. However using minimal CD8 T cell epitope peptide immunisations and a tumour protection model in mice, we have previously shown that functional memory CD8 T cells are not generated unless CD4 T help is provided at the time of CD8 T cell priming. Short-lived effector cells nevertheless are generated in the absence of T help. Aim: To determine the role of CD4 T help in multiple immunisations. Method: Minimal CD8 T cell peptides of HPV16 E7 protein and Ovalbumin were used (with adjuvants Quil-A or IFA) as immunogens in C57BL mice. The presence of effector CD8 T cells were determined by tumour protection assays and was quantified by IFN-gamma ELISPOT assays. Results: In the present study we show that unless T help is provided at the time CD8 T cells are primed, no CD8 effector cells are generated when boosted with the vaccine again in the absence of T help. Our results further show that this failure could be prevented by the inclusion of a T helper peptide during the primary or booster immunisations.

The effects of adolescent cannabis use: How should the empirical evidence inform drug policy for young people? : Meeting abstract

Ethics as a subject is now consistently taught in medical schools within Australia. The theoretical Ethical models used, and the associated clinical discussions, vary between schools. Registrars have further theoretical Ethics teaching within Psychiatry Fellowship Training, and ongoing clinical work that is likely to provide exposure to complex and frequent Ethical dilemmas. As Psychiatry Trainees approach subspecialty training in Child and Adolescent Psychiatry they therefore have a rich experience of both theoretical Ethics teaching and clinical exposure to Ethical issues. In this symposium, the difficulties Child and Adolescent Psychiatry Trainees may have in the integration of multiple theoretical Ethical models are discussed. It is suggested that these difficulties make Ethics Teaching for Child and Adolescent Psychiatry Trainees particularly challenging. This is important given the complex Ethical issues often present when working with Children and their Families. The three main Ethical models of Deontology, Virtue Ethics and Consequentialism are described and their usefulness for the Child and Adolescent Psychiatrist examined. Limitations of these models, and “Four Principles” approaches (such as that of Beauchamp and Childress), for Child and Adolescent Psychiatry, are also considered. Clinical cases are included for discussion. Finally, the ways in which these models may be used to enhance Child and Adolescent Psychiatry Training, and subsequent clinical practice as a Child and Adolescent Psychiatrist, are discussed. The integration of different theoretical Ethical models is considered, with implications identified for clinical practice.

Review of genetic and epigenetic alterations in hepatocarcinogenesis

Hepatocellular carcinoma (HCC) is associated with multiple risk factors and is believed to arise from pre-neoplastic lesions, usually in the background of cirrhosis. However, the genetic and epigenetic events of hepatocarcinogenesis are relatively poorly understood. HCC display gross genomic alterations, including chromosomal instability (CIN), CpG island methylation, DNA rearrangements associated with hepatitis B virus (HBV) DNA integration, DNA hypomethylation and, to a lesser degree, microsatellite instability. Various studies have reported CIN at chromosomal regions, 1p, 4q, 5q, 6q, 8p, 10q, 11p, 16p, 16q, 17p and 22q. Frequent promoter hypermethylation and subsequent loss of protein expression has also been demonstrated in HCC at tumor suppressor gene (TSG), p16, p14, p15, SOCS1, RIZ1, E-cadherin and 14-3-3 sigma. An interesting observation emerging from these studies is the presence of a methylator phenotype in hepatocarcinogenesis, although it does not seem advantageous to have high levels of microsatellite instability. Methylation also appears to be an early event, suggesting that this may precede cirrhosis. However, these genes have been studied in isolation and global studies of methylator phenotype are required to assess the significance of epigenetic silencing in hepatocarcinogenesis. Based on previous data there are obvious fundamental differences in the mechanisms of hepatic carcinogenesis, with at least two distinct mechanisms of malignant transformation in the liver, related to CIN and CpG island methylation. The reason for these differences and the relative importance of these mechanisms are not clear but likely relate to the etiopathogenesis of HCC. Defining these broad mechanisms is a necessary prelude to determine the timing of events in malignant transformation of the liver and to investigate the role of known risk factors for HCC.

Reliability of multiple frequency bioelectrical impedance analysis: An intermachine comparison

The technical reliability (i.e., interinstrument and interoperator reliability) of three SEAC-swept frequency bioimpedance monitors was assessed for both errors of measurement and associated analyses. In addition, intraoperator and intrainstrument variability was evaluated for repeat measures over a 4-hour period. The measured impedance values from a range of resistance-capacitance circuits were accurate to within 3% of theoretical values over a range of 50-800 ohms. Similarly, phase was measured over the range 1 degrees-19 degrees with a maximum deviation of 1.3 degrees from the theoretical value. The extrapolated impedance at zero frequency was equally well determined (+/-3%). However, the accuracy of the extrapolated value at infinite frequency was decreased, particularly at impedances below 50 ohms (approaching the lower limit of the measurement range of the instrument). The interinstrument/operator variation for whole body measurements were recorded on human volunteers with biases of less than +/-1% for measured impedance values and less than 3% for phase. The variation in the extrapolated values of impedance at zero and infinite frequencies included variations due to operator choice of the analysis parameters but was still less than +/-0.5%. (C) 1997 Wiley-Liss, Inc.

Direct evidence for the expression of multiple endogenous retroviruses in the synovial compartment in rheumatoid arthritis

Objective. Circumstantial evidence links retroviruses (RVs) with human autoimmune diseases, The aim of the present study was to obtain direct evidence of RV gene expression in rheumatoid arthritis (RA). Methods. Synovial samples were obtained from patients with RA, patients with osteoarthritis (OA), and normal control subjects, Reverse transcription-polymerase chain reaction (RT-PCR) was performed using synovial RNA and primers to conserved sequences in the polymerase (pol) genes of known RVs. Results. PCR products (n = 857) were cloned and sequenced, Multiple pol transcripts, many with open reading frames, were expressed in every sample, Sequences were aligned and classified into 6 families (F1-F6) that contained 33 groups of known and unknown endogenous RVs (ERVs), each distinguished by a specific, deduced peptide motif, The frequency of sequences in each family was similar between RA, OA, and normal synovial tissue, but differed significantly in RA synovial fluid cells, F1 sequences (undefined, but related to murine and primate type C RVs) were lower in frequency, F2 (ERV-9-related), F4 (HERV-K-related), and F6 (HERV-L-related) sequences were higher in frequency, and F3 (RTVL-H-related) sequences were not detected, in the RA synovial fluid cells compared with the RA synovial tissues. Conclusion. Multiple ERVs are expressed in normal and diseased synovial compartments, but specific transcripts can be differentially expressed in RA.

Prediction of psychological adjustment to multiple sclerosis

This study examined the utility of self-efficacy as a predictor of social activity and mood control in multiple sclerosis (MS). Seventy-one subjects with MS were recruited from people attending an MS centre or from a mailing list and were examined on two occasions that were two months apart. Clinic patients were more disabled than patients who completed assessments by post, but they were of higher socioeconomic status and were less dysphoric; We attempted to predict self-reported performance of mood control and social activity at two months, from self-efficacy or performance on these tasks at pretest. Demographic variables, disorder status, disability, self-esteem and depression were also allowed to compete for entry into multiple regressions. Substantial stability in mood, performance and disability was observed over the two months. In both mood control and social activity, past performance was the strongest predictor of later performance, but self-efficacy also contributed significantly to the prediction. The disability level entered a prediction of social activity; but no other variables predicted either type of performance. A secondary analysis predicting self-esteem at two months also included self-efficacy for social activity, illustrating the contribution of perceived capability to later assessments of self-worth. The study provided support for self-efficacy as a predictor of later behavioural outcomes and self-esteem in multiple sclerosis. (C) 1997 Elsevier Science Ltd.

Analysis and implementation of a new constant acceleration subcycling algorithm

An algorithm for explicit integration of structural dynamics problems with multiple time steps is proposed that averages accelerations to obtain subcycle states at a nodal interface between regions integrated with different time steps. With integer time step ratios, the resulting subcycle updates at the interface sum to give the same effect as a central difference update over a major cycle. The algorithm is shown to have good accuracy, and stability properties in linear elastic analysis similar to those of constant velocity subcycling algorithms. The implementation of a generalised form of the algorithm with non-integer time step ratios is presented. (C) 1997 by John Wiley & Sons, Ltd.

Social adaptation of children with mild intellectual disability: Effects of partial integration within primary school classes

is study examined the social adaptation of children with mild intellectual disability who were either (a) partially integrated into regular primary school classes, or (b) full-time in separate classes, All of the children were integrated in sport and play activities with the whole school. Consistent with previous research, children with intellectual disability were less socially accepted than were a matched group of control children. Children in partially integrated classes received more play nominations than those in separate classes, brit there was no greater acceptance as a best friend. On teachers' reports, disabled children had higher levels of inappropriate social behaviours, but there was no significant difference in appropriate behaviours. Self-assessments by integrated children were more negative than those by children in separate classes, and their peer-relationship satisfaction was lower. Ratings by disabled children of their satisfaction with peer relationships were associated with ratings of appropriate social skills by themselves and their teachers, and with self-ratings of negative behaviour. The study confirmed that partial integration can have negative consequences for children with an intellectual disability.

Measuring macromolecular diffusion using heteronuclear multiple-quantum pulsed-field-gradient NMR

We have previously shown that H-1 pulsed-field-gradient (PFG) NMR spectroscopy provides a facile method for monitoring protein self-association and can be used, albeit with some caveats, to measure the apparent molecular mass of the diffusant [Dingley et al. (1995) J. Biomol. NMR, 6, 321-328]. In this paper we show that, for N-15-labelled proteins, selection of H-1-N-15 multiple-quantum (MQ) coherences in PFG diffusion experiments provides several advantages over monitoring H-1 single-quantum (SQ) magnetization. First, the use of a gradient-selected MQ filter provides a convenient means of suppressing resonances from both the solvent and unlabelled solutes. Second, H-1-N-15 zero-quantum coherence dephases more rapidly than H-1 SQ coherence under the influence of a PFG. This allows the diffusion coefficients of larger proteins to be measured more readily. Alternatively, the gradient length and/or the diffusion delay may be decreased, thereby reducing signal losses from relaxation. In order to extend the size of macromolecules to which these experiments can be applied, we have developed a new MQ PFG diffusion experiment in which the magnetization is stored as longitudinal two-spin order for most of the diffusion period, thus minimizing sensitivity losses due to transverse relaxation and J-coupling evolution.