Skilful prediction of Sahel summer rainfall on inter-annual and multi-year timescales.

Summer rainfall in the Sahel region of Africa exhibits one of the largest signals of climatic variability and with a population reliant on agricultural productivity, the Sahel is particularly vulnerable to major droughts such as occurred in the 1970s and 1980s. Rainfall levels have subsequently recovered, but future projections remain uncertain. Here we show that Sahel rainfall is skilfully predicted on inter-annual and multi-year (that is, >5 years) timescales and use these predictions to better understand the driving mechanisms. Moisture budget analysis indicates that on multi-year timescales, a warmer north Atlantic and Mediterranean enhance Sahel rainfall through increased meridional convergence of low-level, externally sourced moisture. In contrast, year-to-year rainfall levels are largely determined by the recycling rate of local moisture, regulated by planetary circulation patterns associated with the El Niño-Southern Oscillation. Our findings aid improved understanding and forecasting of Sahel drought, paramount for successful adaptation strategies in a changing climate.

Source population characteristics affect heterosis following genetic rescue of fragmented plant populations.

Understanding the relative importance of heterosis and outbreeding depression over multiple generations is a key question in evolutionary biology and is essential for identifying appropriate genetic sources for population and ecosystem restoration. Here we use 2455 experimental crosses between 12 population pairs of the rare perennial plant Rutidosis leptorrhynchoides (Asteraceae) to investigate the multi-generational (F(1), F(2), F(3)) fitness outcomes of inter-population hybridization. We detected no evidence of outbreeding depression, with inter-population hybrids and backcrosses showing either similar fitness or significant heterosis for fitness components across the three generations. Variation in heterosis among population pairs was best explained by characteristics of the foreign source or home population, and was greatest when the source population was large, with high genetic diversity and low inbreeding, and the home population was small and inbred. Our results indicate that the primary consideration for maximizing progeny fitness following population augmentation or restoration is the use of seed from large, genetically diverse populations.

Additional costs of inpatient malnutrition, Victoria, Australia, 2003-2004.

Our objective was to estimate the cost of inpatient malnutrition conditional upon admitting diagnosis and recorded nutritional treatment. We analysed an anonymised administrative data set for inpatients treated in hospitals in Victoria, Australia 2003-2004. The data set included patient-level cost, clinical markers, demographic and episode variables. The data set was analysed to identify codes, which indicated the presence of malnutrition or its treatment. Linear regression was used to ascertain to what extent malnutrition affected the cost of admission. Controlling for the underlying condition and any treatment administered, recorded malnutrition is estimated to add AU $1,745 per admission. The total cost of coded malnutrition to the Victorian public hospital system in 2003-2004 was estimated to be least AU $10.7 million. Only 1.87% of inpatients were coded as malnourished. As administrative data are known to underreport the prevalence of malnutrition, our estimate represents a credible lower boundary on the true cost of inpatient malnutrition.

How different are complications that affect the older adult inpatient?

OBJECTIVE: The incidence and cost of complications occurring in older and younger inpatients were compared. DESIGN: Secondary analysis of hospital-recorded diagnosis and costs for multiday-stay inpatients in 68 public hospitals in two Australian states. MAIN OUTCOME MEASURES: A complication is defined as a hospital-acquired diagnosis that required additional treatment. The Australian Classification of Hospital-Acquired Diagnoses system is used to identify these complications. RESULTS: Inpatients aged >70 years have a 10.9% complication rate, which is not substantially different from the 10.89% complication rate found in patients aged <70 years. Examination of the probability by single years, however, showed that the peak incidence associated with the neonatal period and childbirth is balanced by rates of up to 20% in patients >80 years. Examining the adult patient population (40-70 years), we found that while some common complications are not age specific (electrolyte disorders and cardiac arrhythmias), others (urinary tract and lower respiratory tract infections) are more common in the older adult inpatient. CONCLUSION: For inpatients aged >70 years, the risks of complications increase. The incidence of hospital-acquired diagnoses in older adults differs significantly from incidence rates found in younger cohorts. Urinary tract infection and alteration to mental state are more common in older adult inpatients. Surprisingly, these complexities do not result in additional costs when compared with costs for the same complications in younger adults. Greater awareness of these differing patterns will allow patient safety efforts for older patients to focus on complications with the highest incidence and cost.

Coarse particulate matter emissions from cattle feedlots in Australia.

Open cattle feedlots are a source of air pollutants that include particular matter (PM). Over 24 h, exposure to ambient concentrations of 50 microg m(-3) of the coarse-sized fraction PM (aerodynamic diameter <10 microm [PM(10)]) is recognized as a health concern for humans. The objective of our study was to document PM(10) concentration and emissions at two cattle feedlots in Australia over several days in summer. Two automated samplers were used to monitor the background and in-feedlot PM(10) concentrations. At the in-feedlot location, the PM(10) emission was calculated using a dispersion model. Our measurements revealed that the 24-h PM(10) concentrations on some of the days approached or exceeded the health criteria threshold of 50 microg m(-3) used in Australia. A key factor responsible for the generation of PM(10) was the increased activity of cattle in the evening that coincided with peak concentrations of PM(10) (maximum, 792 microg m(-3)) between 1930 and 2000 h. Rain coincided with a severe decline in PM(10) concentration and emission. A dispersion model used in our study estimated the emission of PM(10) between 31 and 60 g animal(-1) d(-1). These data contribute to needed information on PM(10) associated with livestock to develop results-based environmental policy.

Personal assistance, income and employment: the spinal injuries survey instrument (SISI) and its application in a sample of people with quadriplegia.

INTRODUCTION: Our aim was to ascertain what effect access to personal care package (PCP) has on the labour market activities of people who have a spinal cord injury (SCI). We developed a new instrument called the spinal injuries survey instrument (SISI). The SISI is a 35-item instrument, which contains items on health, education, employment, along with measures of personal assistance, mobility and psychological attribution style. MATERIALS AND METHODS: The SISI was administered, with the Short Form 36 (SF-36) health status instrument, to 250 people with an SCI. The response rate was 72%. A retrospective, matched case-control sampling approach matched individuals who received a PCP, with a cohort who did not. The matching criteria included the site and severity of spinal lesion, age and gender. RESULTS: Although data on the reliability of the instrument are currently lacking, our empirical results are consistent with other studies: (1) mean annual health care costs (AUD$8741) are comparable with Walsh's estimates (2) SF-36 data support Kreuter's contention that mental health is resilient to SCI and (3) a post-injury employment rate of 29.7% corroborates Murphy et al. We present additional data describing income, educational attainment and family support. DISCUSSION: Our discussion borrows a conceptualization of disability by Sen, that includes both an 'earning handicap' (an impediment to earn income) and a 'conversion handicap' (an impediment to the enjoyment of income). Our application of the SISI provides evidence of both. The labour income of people with quadriplegia is AUD$10,007 per annum, while diminished health status, increased out-of-pocket health expenditure and loss of time suggest a conversion handicap.

Unprecedented chromosomal diversity and behaviour modify linkage patterns and speciation potential: structural heterozygosity in an Australian spider.

The Huntsman spider Delena cancerides shows an extraordinary level of chromosomal diversity and meiotic complexity. Some populations form normal bivalents at male meiosis, but 14 populations form chains of chromosomes. Six of these populations form two chains, and so show segregation behaviour which is beyond our current understanding of meiotic processes. Chromosomal variation of this sort is rarely tolerated in other species, because the segregation of long chromosome chains frequently results in gametes with too many or too few chromosomes. The resulting reproductive failure may form the basis for reproductive isolation in many species, and so the mechanisms that allow D. cancerides to segregate long chromosome chains have allowed this species to maintain cohesion despite extensive chromosomal variation over its range. The effect these chromosome chains have on the population genetics of the species is discussed, and a model for the evolution of the system is proposed.

Catchments catch all: long-term population history of a giant springtail from the southeast Australian highlands--a multigene approach.

Phylogeography can reveal evolutionary processes driving natural genetic-geographical patterns in biota, providing an empirical framework for optimizing conservation strategies. The long-term population history of a rotting-log-adapted giant springtail (Collembola) from montane southeast Australia was inferred via joint analysis of mitochondrial and multiple nuclear gene genealogies. Contemporary populations were identified using multilocus nuclear genotype clustering. Very fine-scale sampling combined with nested clade and coalescent-based analyses of sequences from mitochondrial cytochrome oxidase I and three unlinked nuclear loci uncovered marked population structure, deep molecular divergences, and abrupt phylogeographical breaks over distances on the order of tens of kilometres or less. Despite adaptations that confer low mobility, rare long-distance gene flow was implicated: novel computer simulations that jointly modelled stochasticity inherent in coalescent processes and that of DNA sequence evolution showed that incomplete lineage sorting alone was unable to explain the observed spatial-genetic patterns. Impacts of Pleistocene or earlier climatic cycles were detected on multiple timescales, and at least three putative moist forest refuges were identified. Water catchment divisions predict phylogeographical patterning and present-day population structure with high precision, and may serve as an excellent surrogate for biodiversity indication in sedentary arthropods from topographically heterogeneous montane temperate forests.

Economic analysis of a community-based falls prevention program.

OBJECTIVES: To undertake a cost-benefit analysis of 'Stay on Your Feet', a community-based falls prevention program targeting older people at all levels of risk in New South Wales, Australia. Hospital separations were monitored in the intervention region, a control region and for the state of New South Wales as a whole. Changing admission patterns over the intervention period were used to assess the impact of the program. METHODS: Cost-benefit analysis compared the costs of the program with two estimates of savings from avoided hospital admissions. The first compared the cost of hospital admissions in the intervention region to a control region of similar demographics, while the second compared hospital utilization in the intervention region with the state of New South Wales as a whole using falls-related hospital diagnosis related group (DRG) codes. RESULTS: The total direct costs of the program were estimated at A dollars 781,829. Both methods identified clear overall net benefits ranging from A dollars 5.4 million for avoided hospitalizations alone to A dollars 16.9 million for all avoided direct and indirect costs. The confidence intervals around these estimates were small. The average overall benefit to cost ratio for the intervention as a whole was 20.6:1. CONCLUSIONS: These findings suggest that well-designed community-based interventions targeting falls prevention among older people are highly cost effective and a wise investment for all levels of government. The models used are conservative and are likely to underestimate the real benefit of the intervention, which may have lasted for some time beyond the life of the program.

Phylogeography recapitulates topography: very fine-scale local endemism of a saproxylic 'giant' springtail at Tallaganda in the Great Dividing Range of south-east Australia.

Comparative phylogeography can reveal processes and historical events that shape the biodiversity of species and communities. As part of a comparative research program, the phylogeography of a new, endemic Australian genus and species of log-dependent (saproxylic) collembola was investigated using mitochondrial sequences, allozymes and anonymous single-copy nuclear markers. We found the genetic structure of the species corresponds with five a priori microbiogeographical regions, with population subdivision at various depths owing to palaeoclimatic influences. Closely related mtDNA haplotypes are codistributed within a single region or occur in adjacent regions, nuclear allele frequencies are more similar among more proximate populations, and interpopulation migration is rare. Based on mtDNA divergence, a late Miocene-late Pliocene coalescence is likely. The present-day distribution of genetic diversity seems to have been impacted by three major climatic events: Pliocene cooling and drying (2.5-7 million years before present, Mybp), early Pleistocene wet-dry oscillations (c. 1.2 Mybp) and the more recent glacial-interglacial cycles that have characterized the latter part of the Quaternary (<0.4 Mybp).

Phylogenetics of Planipapillus, lawn-headed onychophorans of the Australian Alps, based on nuclear and mitochondrial gene sequences.

We addressed phylogenetic relationships among species of Planipapillus, a clade of oviparous onychophorans from southeastern mainland Australia, to create a framework for understanding the evolution of the modified male head papillae used in mating in this clade. We sequenced fragments of two mitochondrial genes, COI and 12S rRNA, and a nuclear intron from the fushi tarazu gene, for individuals from 14 putative species of Planipapillus and six outgroups. We analyzed these data under both parsimony and likelihood criteria, incorporating heterogeneous parameter fitting guided by likelihood ratio tests. These analyses result in strong, congruent support for many clades. We infer multiple independent origins of spikes in Planipapillus male head structures.

Decomposition and nitrogen mineralization from biosolids and other organic materials: relationship with initial chemistry.

Biosolids are effective forest fertilizers. In order to facilitate their use it is important that one be able to predict the amount and rate of mineralization of nutrients, particularly nitrogen, and the relationship between substrate chemistry and N release. We examined the relationships between substrate quality and nitrogen release in a variety of organic materials. Rates of decomposition and net N mineralization from four biosolids, wheat straw, paper fines, and Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] needle litter were measured during 391-d incubations in a greenhouse, and at two field sites in wet coastal and dry interior forests. Decomposition rates were best predicted by a model incorporating the ratio of carbon to organic matter. The decomposition model extrapolated well to the field when site-specific correction factors were applied. There was a weak relationship between rates of decomposition and net N mineralization. Rates of net N mineralization were best predicted by a model incorporating the initial organic N concentration and the proportion of phenolic C determined from solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. The mineralization model extrapolated less well to the field, but the effect of substrate chemistry was still apparent. Among the four biosolids there was a strong correlation between organic N concentration and indices or protein determined from 13C NMR, suggesting that these protein indices may be useful for predicting N mineralization from biosolids. There was some evidence that the protein content and N mineralization in biosolids may be predictable from the sewage treatment process employed.

Current advances in liver transplantation.

Advances in the medical and surgical management of patients undergoing liver transplantation have made transplantation the method of choice for dealing with end-stage liver disease. With the availability of anti-viral agents such as interferon and ribavirin, pre and post transplant treatment of hepatitis C, the most common indication for liver transplantation, is now possible. The use of high dose hepatitis B immune globulin (HBIG) and lamivudine has decreased the incidence and severity of recurrence of hepatitis B after liver transplantation. Multimodal therapy including chemoembolization for hepatocellular carcinoma has made liver transplantation a viable option for selected patients with primary liver cancer. The development of more potent immunosuppressive agents has dramatically decreased the incidence of acute rejection, while the search for a solution to the problem of chronic rejection continues. Alcoholic liver disease remains a challenge for transplant physicians and surgeons; however, careful patient selection results in a relatively low rate of recidivism.Surgical advances in liver transplantation have focused on eliminating associated morbidity and mortality as well as expanding the donor pool. Veno-venous bypass (VVB) and T-tube stenting, which were once considered essential techniques in liver transplantation, are now only rarely, if ever, necessary. Operative time, blood product usage, and time to extubation, as well as intensive care unit stay, have all been significantly reduced by elimination of VVB without associated morbidity. Elimination of T-tube usage has also effectively decreased morbidity. Donor expansion has become critical as the need for liver transplants exceeds donor availability. Use of marginal donors, including older donors, donors with up to 40% fat content, and donors with high pressor requirements, has proven to be a safe and effective means of increasing the donor pool. In-situ splitting of donors is the most promising technical advance in liver transplantation. This technique, along with living-related liver transplantation, is very important for providing donors to the pediatric population where donor availability is even more limited.

Evaluation of a urine chemistry analyser.

Using an automated urine analyser in the ward may improve the accuracy of urine testing as nurses no longer have to rely on making subjective colour comparisons. Staff in one urology unit tested an analyser for ease of use, convenience and practicality.

Phylogenetic relationships among onychophora from Australasia inferred from the mitochondrial cytochrome oxidase subunit I gene.

Nucleotide sequence variation in a region of the mitochondrial cytochrome oxidase subunit I (COI) gene (456 bp) was examined for 26 onychophorans representing 15 genera of the family Peripatopsidae from Australasia. Sequence analysis revealed high intergeneric COI sequence divergence (up to 20.6% corrected) but low amino acid substitution rates, with high levels of transitional saturation evident. Among unambiguously alignable sequences, parsimony and distance analyses revealed a broadly congruent tree topology, robust to various algorithms and statistical analysis. There are two major groupings. One, largely unresolved, consists entirely of Australian mainland taxa. The other, for which there is convincing support, includes all of the New Zealand and Tasmanian taxa together with one mainland Australian species. In respect of the two major groupings, this topology is consistent with previous morphologically based phylogenies and provides further evidence for an ancient radiation within the mainland Australian Onychophora. The biogeographic implications of the close affinities revealed between the Tasmanian and New Zealand taxa are discussed.

Human hepatocytes express an array of proinflammatory cytokines after agonist stimulation or bacterial invasion.

Inflammatory cells infiltrate the liver in response to microbial infection or hepatic injury. To assess the potential role hepatocytes may play in initiating or amplifying the acute inflammatory response in the liver, we used three human hepatocyte cell lines and primary human hepatocyte cultures to characterize the repertoire of cytokines that can be expressed and regulated in hepatocytes in response to agonist stimulation or bacterial infection. As reported herein, a proinflammatory cytokine gene program that includes C-X-C and C-C chemokines [interleukin-8(IL-8), growth related (GRO)-alpha, GRO-beta, GRO-gamma, epithelial neutrophil activating peptide-78 (ENA-78), and RANTES] and the cytokines tumor necrosis factor-alpha (TNF-alpha) and macrophage colony stimulating factor was upregulated in human hepatocytes after stimulation with IL-1 alpha or TNF-alpha or bacterial invasion. In contrast, expression of hematopoietic/ lymphoid growth factors by the same cells was either down-regulated (erythropoietin and stem cell factor) or unchanged (IL-7 and IL-15) in response to the identical stimuli. Hepatocytes did not express cytokines that often are associated with the regulation of antigen-specific immune responses (IL-2, IL-4, IL-5, IL-10, IL-12p40, IL-13, and interferon-gamma) or genes for several other proinflammatory cytokines [IL-1 alpha, IL-6, monocyte chemotactic protein-1 (MCP-1), and MCP-3] or hematopoietic growth factors (granulocyte colony stimulating factor, granulocyte macrophage colony stimulating factor, IL-3, and IL-11). Together, these studies suggest that hepatocytes can both initiate and amplify acute inflammatory responses in the liver through the regulated expression and secretion of a specific array of proinflammatory cytokines.

Distinct delta T cell receptor repertoires in monozygotic twins concordant for coeliac disease.

One of the hallmarks of coeliac disease, both active and treated, is an increased number and proportion of gamma/delta intraepithelial T lymphocytes in the small intestinal mucosa, and an increased number of gamma/delta T cells in the small intestinal mucosa of coeliac disease patients has been associated with the inheritance of specific HLA class II DQ alleles. Nonetheless, the contribution of genetic factors to the development of the T cell receptor (TCR) delta repertoire in coeliac disease is not known. We have assessed the contribution of genetic factors to development of the TCR delta repertoire in coeliac disease, by characterizing the junctional diversity of TCR delta transcripts expressed in the intestine and peripheral blood of a pair of monozygotic (MZ) twins concordant for coeliac disease. TCR Vdelta1, Vdelta2 and Vdelta3 transcripts from small intestinal and colon biopsies, and from peripheral blood mononuclear cells, were amplified by polymerase chain reaction (PCR) and the complementarity determining region (CDR)3 domains of TCR delta transcripts were analysed by denaturing PAGE and direct nucleotide sequencing. The repertoire of TCR delta transcripts and CDR3 amino acid motifs in the intestine and peripheral blood of MZ twins concordant for coeliac disease exhibited no overlap. The TCR delta repertoire in each twin was oligoclonal, and complexity of the junctional regions of their TCR delta transcripts was typical of the repertoire in healthy adults. Thus, genetically identical individuals with coeliac disease have distinct, non-overlapping TCR delta repertoires. Moreover, genetic factors that determine disease susceptibility do not appear to select for specific TCR delta sequences or CDR3 amino acid motifs.

Evidence from 12S ribosomal RNA sequences that onychophorans are modified arthropods.

The evolutionary relationships of the onychophorans (velvet worms) and the monophyly of the arthropods have generated considerable debate. Cladistic analyses of 12S ribosomal RNA sequences indicate that arthropods are monophyletic and include the onychophorans. Maximum parsimony analyses and monophyly testing within arthropods indicate that myriapods (millipedes and centipedes) form a sister group to all other assemblages, whereas crustaceans (shrimps and lobsters) plus hexapods (insects and allied groups) form a well-supported monophyletic group. Parsimony analysis further suggests that onychophorans form a sister group to chelicerates (spiders and scorpions) and crustaceans plus hexapods, but this relationship is not well supported by monophyly testing. These relationships conflict with current hypotheses of evolutionary pathways within arthropods.