Does maintaining green leaf area in sorghum improve yield under drought? I. Leaf growth and senescence

Production of sorghum [Sorghum bicolor (L.) Moench], an important cereal crop in semiarid regions of the world, is often limited by drought. When water is limiting during the grain-filling period, hybrids possessing the stay-green trait maintain more photosynthetically active leaves than hybrids not possessing this trait. To improve yield under drought, knowledge of the extent of genetic variation in green leaf area retention is required. Field studies were undertaken in north-eastern Australia on a cracking and self-mulching gray clay to determine the effects of water regime and hybrid on the components of green leaf area at maturity (GLAM). Nine hybrids varying in stay-green were grown under a fully irrigated control, postflowering water deficit, and terminal (pre- and postflowering) water deficit. Water deficit reduced GLAM by 67% in the terminal drought treatment compared with the fully irrigated control. Under terminal water deficit, hybrids possessing the B35 and KS19 sources of stay-green retained more GLAM (1260 cm(2) plant(-1)) compared with intermediate (780 cm(2) plant(-1)) and senescent (670 cm(2) plant(-1)) hybrids. RQL12 hybrids (KS19 source of stay-green) displayed delayed onset and reduced rate of senescence; A35 hybrids displayed only delayed onset. Visual rating of green leaf retention was highly correlated with measured GLAM, although this procedure is constrained by an inability to distinguish among the functional mechanisms determining the phenotype. Linking functional rather than phenotypic differences to molecular markers may improve the efficiency of selecting for traits such as stay-green.

Does maintaining green leaf area in sorghum improve yield under drought? II. Dry matter production and yield

Retention of green leaf area at maturity (GLAM), known as stay-green, is used as an indicator of postanthesis drought resistance in sorghum [Sorghum bicolor (L.) Moench] breeding programs in the USA and Australia. The critical issue is whether maintaining green leaves under postanthesis drought increases grain yield in stay-green compared with senescent hybrids. Field studies were undertaken in northeastern Australia on a cracking and self-mulching gay clay. Nine closely related hybrids varying in rate of leaf senescence were grown under two water-limiting regimes, post-flowering water deficit and terminal (pre- and postflowering) water deficit, and a fully irrigated control. Under terminal water deficit, grain yield tvas correlated positively with GLAM (r = 0.75**) and negatively with rate of leaf senescence (r = -0.74**). Grain yield also increased by approximate to 0.35 Mg ha(-1) for every day that onset of leaf senescence was delayed beyond 76 DAE in the water-limited treatments. Stay-green hybrids produced 47% more postanthesis biomass than their senescent counterparts (920 vs. 624 g m(-2)) under the terminal water deficit regime. No differences in grain yield were found among eight of the nine hybrids under fully irrigated conditions, suggesting that the stay-green trait did not constrain yield in the well-watered control. The results indicate that sorghum hybrids possessing the stay-green trait have a significant yield advantage under postanthesis drought compared with hybrids not possessing this trait.

Probability of axillary node involvement in patients with tubular carcinoma of the breast

The aim of this study was to investigate the frequency of axillary metastasis in women with tubular carcinoma (TC) of the breast. Women who underwent axillary dissection for TC in the Western Sydney area (1984-1995) were identified retrospectively through a search of computerized records. A centralized pathology review was performed and tumours were classified as pure tubular (22) or mixed tubular (nine), on the basis of the invasive component containing 90 per cent or more, or 75-90 per cent tubule formation respectively. A Medline search of the literature was undertaken to compile a collective series (20 studies with a total of 680 patients) to address the frequency of nodal involvement in TC. A quantitative meta-analysis was used to combine the results of these studies. The overall frequency of nodal metastasis was five of 31 (16 per cent); one of 22 pure tubular and four of nine mixed tumours (P = 0.019). None of the tumours with a diameter of 10 mm or less (n = 16) had nodal metastasis compared with five of 15 larger tumours (P = 0.018). The meta-analysis of 680 women showed an overall frequency of nodal metastasis in TC of 13.8 (95 per cent confidence interval 9.3-18.3) per cent. The frequency of nodal involvement was 6.6 (1.7-11.4) per cent in pure TC (n = 244) and 25.0 (12.5-37.6) per cent in mixed TC (n = 149). A case may be made for observing the clinically negative axilla in women with a small TC (10 mm or less in diameter).

Small area population disease burden

Small area health statistics has assumed increasing importance as the focus of population and public health moves to a more individualised approach of smaller area populations. Small populations and low event occurrence produce difficulties in interpretation and require appropriate statistical methods, including for age adjustment. There are also statistical questions related to multiple comparisons. Privacy and confidentiality issues include the possibility of revealing information on individuals or health care providers by fine cross-tabulations. Interpretation of small area population differences in health status requires consideration of migrant and Indigenous composition, socio-economic status and rural-urban geography before assessment of the effects of physical environmental exposure and services and interventions. Burden of disease studies produce a single measure for morbidity and mortality - disability adjusted life year (DALY) - which is the sum of the years of life lost (YLL) from premature mortality and the years lived with disability (YLD) for particular diseases (or all conditions). Calculation of YLD requires estimates of disease incidence (and complications) and duration, and weighting by severity. These procedures often mean problematic assumptions, as does future discounting and age weighting of both YLL and YLD. Evaluation of the Victorian small area population disease burden study presents important cross-disciplinary challenges as it relies heavily on synthetic approaches of demography and economics rather than on the empirical methods of epidemiology. Both empirical and synthetic methods are used to compute small area mortality and morbidity, disease burden, and then attribution to risk factors. Readers need to examine the methodology and assumptions carefully before accepting the results.

Community structure of Quaternary coral reefs compared with Recent life and death assemblages

This paper assesses the reliability with which fossil reefs record the diversity and community structure of adjacent Recent reefs. The diversity and taxonomic composition of Holocene raised fossil reefs was compared with those of modern reef coral life and death assemblages in adjacent moderate and low-energy shallow reef habitats Of Madang Lagoon, Papua New Guinea. Species richness per sample area and Shannon-Wiener diversity (H') were highest in the fossil reefs, intermediate in the life assemblages, and lowest in the death assemblages. The taxonomic composition of the fossil reefs was most similar to the combination of the life and death assemblages from the modern reefs adjacent to the two fossil reefs. Depth zonation was recorded accurately in the fossil reefs. The Madang fossil reefs represent time-averaged composites of the combined life and death assemblages as they existed at the time the reef was uplifted. Because fossil reefs include overlapping cohorts from the life and death assemblages, lagoonal facies of fossil reefs are dominated by the dominant sediment-producing taxa, which are not necessarily the most abundant in the life assemblage. Rare or slow-growing taxa accumulate more slowly than the encasing sediments and are underrepresented in fossil reef lagoons. Time-averaging dilutes the contribution of rare taxa, rather than concentrating their contribution. Consequently, fidelity indices developed for mollusks in sediments yield low values in coral reef death and fossil assemblages. Branching corals dominate lagoonal facies of fossil reefs because they are abundant, they grow and produce sediment rapidly, and most of the sediment they produce is not exported. Fossil reefs distinguished kilometer-scale variations in community structure more clearly than did the modern life assemblages. This difference implies that fossil,reefs may provide a better long-term record of community structure than modern reefs. This difference also suggests that modern kilometer-scale variation in coral reef community structure may have been reduced by anthropogenic degradation, even in the relatively unimpacted reefs of Madang Lagoon. Holocene and Pleistocene fossil reefs provide a time-integrated historical record of community composition and may be used as long-term benchmarks for comparison with modern, degraded, nearshore reefs. Comparisons between fossil reefs and degraded modern reefs display gross changes in community structure more effectively than they demonstrate local extinction of rare taxa.

The co-segregation of psychosis and selected physical disorders within families of patients with psychosis versus well controls

While it has been reported that individuals with psychosis are at increased or decreased risk of various physical disorders such as cancer and rheumatoid arthritis, there has been less research on the co-segregation of physical disorders within the first-degree relatives of those with psychosis compared to relatives of well controls. The aim of this study was to examine these issues in an epidemiologically informed catchment-area based case-control study. Patients with psychosis were drawn from a prevalence study undertaken as part of the Australian National Mental Health Survey. In addition, we recruited well controls who resided in the same catchment area. For each subject, we drew pedigrees and used a structured checklist to assess the presence of selected psychiatric disorders, and selected disorders such as multiple sclerosis, epilepsy, spina bifida, thyroid disorders, diabetes, asthma and eczema. Data based on pedigrees from 293 individuals with psychosis and 292 well controls was available. As expected, the odds of havingschizophrenia and affective disorders were significantly increased in the families of cases versus controls. The odds of havingeczema were significantly reduced in the relatives of those with psychosis. All other disorders occurred with equal frequency in cases versus control pedigrees. Current theories of eczema suggest that an absence of early life exposure to antigens and infectious agents may fail to prime the na¨ıve immune system, and leave the person at increased risk of eczema. The results of this study suggest that genetic andror environmental factors that facilitate psychosis may protect against eczema. The Stanley Foundation supported this project.

Finger and A-B ridge count, and fluctuating asymmetry in psychosis: A catchment area case-control study

Dermatoglyphic measures are of interest to schizophrenia research because they serve as persistent markers of deviant development in foetal life. Several studies have reported alterations in A–B ridge counts, total finger ridge counts and measures related to asymmetry in schizophrenia. The aim of this study was to assess these measures in an Australian catchment area, case-control study. Individuals with psychosisŽns246.were drawn from a catchment-area prevalence study, and well controlsŽns229. were recruited from the same area. Finger and palm prints were taken usingan inkless technique and all dermatoglyphic measures were assessed by a trained rater blind to case status. The dermatoglyphic measures Žfinger ridge count, A–B ridge count, and their derived asymmetry measures. were divided into quartiles based on the distribution of these variables in controls. The main analysis Žlogistic regression controlled for age and sex.examined all psychotic disorders, with planned subgroup analyses comparing controls with Ž1. nonaffective psychosis Žschizophrenia, delusional disorder, schizophreniform psychosis, atypical psychosis.andŽ2. affective psychosis Ždepression with psychosis, bipolar disorder, schizoaffective psychosis.. There were no statistically significant alterations in the odds of havinga psychotic disorder for any of the dermatoglyphic measures. The results did not change when we examined affective and nonaffective psychosis separately. The dermatoglyphic features that distinguish schizophreniar psychosis in other studies were not identified in this Australian study. Regional variations in these findings may provide clues to differential ethnicrgenetic and environmental factors that are associated with schizophrenia. The Stanley Foundation supported this project.

Relationship of interleukin-6 and tumor necrosis factor-alpha with muscle mass and muscle strength in elderly men and women: The health ABC study

Background. A decline in muscle mass and muscle strength characterizes normal aging. As clinical and animal studies show it relationship between higher cytokine levels and low muscle mass, the aim of this study was to investigate whether markers, of inflammation are associated with muscle mass and strength in well-functioning elderly persons. Methods. We Used baseline data (1997-1998) of the Health, Aging, and Body Composition (Health ABC) Study on 3075 black and white men and women aged 70-79 years. Midthigh muscle cross-sectional area (computed tomography), appendicular muscle mass (dual-energy x-ray ab absorptiometry). isokinetic knee extensor strength (KinCom). and isometric inip strength were measured. plasma levels of interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were assessed by enzyme-linked immunosorbent assay (ELISA). Results. Higher cytokine levels were generally associated with lower muscle mass and lower muscle strength. The most consistent relationship across the gender and race groups was observed for IL-6 and grip strength: per SD increase in IL-6, grip strength was 1.1 to 2.4 kg lower (p < .05) after adjustment for age, clinic Site. health status, medications, physical activity. smoking. height. and body fat. Ail overall measure of elevated cytokine level was created by combining the levels of IL-6 and TNF-alpha. With the exception of white men, elderly persons having high levels of IL-6 (> 1.80 pg/ml) as well as high levels of TNF-alpha (> 3.20 pg/ml) had a smaller muscle area, less appendicular mass. a lower knee extensor strength. and a lower grip strength compared to those with low levels of both cytokines. Conclusions. Higher plasma concentrations of IL-6 and TNF-alpha are associated with lower muscle mass and lower muscle strength in well-functioning older men and women. Higher cytokine levels. as often observed in healthy older persons. may contribute to the loss Of muscle mass and strength that accompanies aging.

Premovement activity of the pre-supplementary motor area and the readiness for action: Studies of time-resolved event-related functional MRI

The supplementary motor area (SMA) is thought to play in important role in the preparation and organisation of voluntary movement. It has long been known that cortical activity begins to increase up to 2 s prior to voluntary self-initiated movement. This increasing premovement activity measured in EEG is known as the Bereitschaftspotential or readiness potential. Modern functional brain imaging methods, using event-related and time-resolved functional MRI techniques, are beginning to reveal the role of the SMA, and in particular the more anterior pre-SMA, in premovement activity associated with the readiness for action. In this paper we review recent studies using event-related time-resolved fMRI methods to examine the time-course of activation changes within the SMA throughout the preparation, readiness and execution of action. These studies suggest that the preSMA plays a common role in encoding or representing actions prior to our own voluntary self-initiated movements, during motor imagery, and from the observation of others' actions. We suggest that the pre-SMA generates and encodes motor representations which are then maintained in readiness for action. (c) 2005 Elsevier B.V. All rights reserved.

Mechanism of ribonuclease inhibition by ribonuclease inhibitor protein based on the crystal structure of its complex with ribonuclease A

We describe the mechanism of ribonuclease inhibition by ribonuclease inhibitor, a protein built of leucine-rich repeats, based on the crystal structure of the complex between the inhibitor and ribonuclease A. The structure was determined by molecular replacement and refined to an R(cryst) of 19.4% at 2.5 Angstrom resolution. Ribonuclease A binds to the concave region of the inhibitor protein comprising its parallel beta-sheet and loops. The inhibitor covers the ribonuclease active site and directly contacts several active-site residues. The inhibitor only partially mimics the RNase-nucleotide interaction and does not utilize the pi phosphate-binding pocket of ribonuclease A, where a sulfate ion remains bound. The 2550 Angstrom(2) of accessible surface area buried upon complex formation may be one of the major contributors to the extremely tight association (K-i = 5.9 x 10(-14) M). The interaction is predominantly electrostatic; there is a high chemical complementarity with 18 putative hydrogen bonds and salt links, but the shape complementarity is lower than in most other protein-protein complexes. Ribonuclease inhibitor changes its conformation upon complex formation; the conformational change is unusual in that it is a plastic reorganization of the entire structure without any obvious hinge and reflects the conformational flexibility of the structure of the inhibitor. There is a good agreement between the crystal structure and other biochemical studies of the interaction. The structure suggests that the conformational flexibility of RI and an unusually large contact area that compensates for a lower degree of complementarity may be the principal reasons for the ability of RI to potently inhibit diverse ribonucleases. However, the inhibition is lost with amphibian ribonucleases that have substituted most residues corresponding to inhibitor-binding residues in RNase A, and with bovine seminal ribonuclease that prevents inhibitor binding by forming a dimer. (C) 1996 Academic Press Limited

Fuel stagnation temperature effects on mixing with supersonic combustion flows

An experimental study of the effect of fuel stagnation temperature on mixing in a supersonic hydrogen-air flame is described, The combustor consisted of a constant-area rectangular duct with a centrally located fuel-injection strut that spanned the width. A high-enthalpy stream of air was supplied by a free-piston shock tunnel, and heated hydrogen fuel, supplied by a gun-tunnel, was injected into the freestream as a coflowing planar jet. The freestream total enthalpies were 5.6, 6.5, and 9 MJ/kg, and fuel stagnation temperatures were 300, 450, and 700 K, Raising the fuel stagnation temperature increased the fuel velocity to be near that of the airstream and resulted in a decrease in the mixing rate, Even as the fuel and air velocities became equal, significant mixing still occurred because of a large difference in density, Increasing the freestream enthalpy reduced the difference between the initial air temperature and the adiabatic flame temperature, which in turn reduced the heat addition, and subsequently, the amount of pressure rise in the duct.

Zipping up transcription factors: Rational design of anti-Jun and anti-Fos peptides

Various members of the bZip and bHLH-Zip families of eukaryotic transcription factors, including Jun, Fos, and Myc, have been identified as oncoproteins; mutation or deregulated expression of these proteins leads to certain types of cancer. These proteins can only bind to their cognate DNA enhancer sites following homodimerization, or heterodimerization with another family member, via their leucine zipper domain. Thus, a novel anticancer strategy would be to inhibit dimerization of these proteins, thereby blocking their DNA binding and transactivation functions. In this paper we show that it is possible to rationally design leucine zipper peptides that bind with high affinity to the leucine zipper dimerization domains of c-Jun and c-Fos, thus preventing the formation of functional c-Jun homodimers and c-Jun:c-Fos heterodimers; we refer to such peptides as superzippers (SZs). In vivo, c-Jun:SZ and c-Fos:SZ heterodimers should be nonfunctional as they lack one of the two basic domains that are essential for DNA binding. While the transport of a peptidic agent into cells often poses a severe obstacle to its therapeutic use, we show that a 46-residue leucine zipper peptide can be transported into HeLa cells by coupling it to a 17-residue carrier peptide from the Antennapedia homeodomain, thus paving the way for detailed studies of the therapeutic potential of superzipper peptides.

Whale sharks in Ningaloo Marine Park: managing tourism in an Australian marine protected area

The whale shark is the largest fish in the ocean, A tourism industry based on interacting with whale sharks has developed recently in Ningaloo Marine Park, off the coast of Western Australia, This is the only known, accessible place in the world where whale sharks congregate in significant numbers, Results from surveys of participants in the 'whale shark experience' are reported, with the experience found to be extremely satisfying for most consumers, Yet management questions relating to diver-to-shark separation distances, the appropriate number of operators, and the use of regulation, self-regulation and economic instruments, remain, The nexus between experiential aspects of the whale shark attraction and such management concerns is examined, and the usefulness of appropriate research in resolving management questions established, It is concluded that a judicious combination of management approaches is required to ensure the sustainable development of the whale shark tourism industry. (C) 1997 Elsevier Science Ltd.

Relationship between use of technology and employment rates for people with physical disabilities in Australia: Implications for education and training programmes

This study examined the impact of computer and assistive device use on the employment status and vocational modes of people with physical disabilities in Australia. A survey was distributed to people over 15 years in age with physical disabilities living in the Brisbane area. Responses were received from 82 people, including those with spinal cord injuries, cerebral palsy and muscular dystrophy. Of respondents 46 were employed, 22 were unemployed, and 12 were either students or undertaking voluntary work. Three-quarters of respondents used a computer in their occupations, while 15 used assistive devices. Using logistic regression analysis it was found that gender, education, level of computer skill and computer training were significant predictors of employment outcomes. Neither the age of respondent nor use of assistive software were significant predictors. From information obtained in this study guidelines for a training programme designed to maximize the employability of people with physical disabilities were developed.