Vector competence of Coquillettidia linealis (Skuse) (Diptera : Culicidae) for Ross River and Barmah Forest viruses

Coquillettidia linealis is a severe pest on some of the Moreton Bay islands in Queensland, Australia, but little is known of its breeding habitats and biology. Because of its high abundance and its association with Ross River (RR) and Barmah Forest (BF) viruses by field isolation, its vector competence was evaluated in the laboratory by feeding dilutions of both viruses in blood. For RR, Cq. linealis was of comparable efficiency to Ochlerotatus vigilax (Skuse), recognised as being a major vector. Results were as follows for Cq. linealis and Oc. vigilax , respectively: dose to infect 50%, 10(2.2) and

Present and future pharacotherapy for heart failure

The pharmacotherapy currently recommended by the American College of Cardiology and the American Heart Association for heart failure (HF) is a diuretic, an angiotensin-converting enzyme inhibitor (ACEI), a β-adrenoceptor antagonist and (usually) digitalis. This current treatment of HF may be improved by optimising the dose of ACEI used, as increasing the dose of lisinopril increases its benefits in HF. Selective angiotensin receptor-1 (AT1) antagonists are effective alternatives for those who cannot tolerate ACEIs. AT1 antagonists may also be used in combination with ACEIs, as some studies have shown cumulative benefits for the combination. In addition to being used in Stage IV HF patients, in whom it has a marked benefit, spironolactone should be studied in less severe HF and in the presence of β-blockers. The use of carvedilol, extended-release metoprolol and bisoprolol should be extended to severe HF patients as these agents have been shown to decrease mortality in this group. The ancillary properties of carvedilol, particularly antagonism at prejunctional β-adrenoceptors, may give it additional benefits to selective β1-adrenoceptor antagonists. Celiprolol and bucindolol are not the β-blockers of choice in HF, as they do not decrease mortality. Although digitalis does not reduce mortality, it remains the only option for a long-term positive inotropic effect, as the long-term use of the phosphodiesterase inhibitors is associated with increased mortality. The calcium sensitising drug levosimendan may be useful in the hospital treatment of decompensated HF to increase cardiac output and improve dyspnoea and fatigue. The antiarrhythmic drug amiodarone should probably be used in patients at high risk of arrhythmic or sudden death, although this treatment may soon be superseded by the more expensive implanted cardioverter defibrillators, which are probably more effective and have fewer side effects. The natriuretic peptide nesiritide has recently been introduced for the hospital treatment of decompensated HF. Novel drugs that may be beneficial in the treatment of HF include the vasopeptidase inhibitors and the selective endothelin-A receptor antagonists but these require much more investigation. However, disappointing results have been obtained in a large clinical trial of the tumour necrosis factor α antagonist etanercept, where no likelihood of a difference between placebo and etanercept was observed. Small clinical trials with recombinant growth hormone to thicken ventricles in dilated cardiomyopathy have given variable results.

Competition and resource availability in an annual plant community dominated by an invasive species, Carrichtera annua (L. Aschers.), in South Australia

The last decade has seen spirited debates about how resource availability affect the intensity of competition. This paper examines the effect that a dominant introduced species, Carrichtera annua, has upon the winter annual community in the arid chenopod shrublands of South Australia. Manipulative field experiments were conducted to assess plant community response to changing below-ground resource levels and to the manipulation of the density of C. annua. Changes in the density of C. annua had little effect on the abundance of all other species in the guild. Nutrient addition produced an increase in the biomass of the most abundant native species, Crassula colorata. An analysis of the root distribution of the main species suggested that the areas of soil resource capture of C. annua and C. colorata are largely segregated. Our results suggest that intraspecific competition may be stronger than interspecific competition, controlling the species responses to increased resource availability. The results are consistent with a two-phase resource dynamics systems, with pulses of high resource availability triggering growth, followed by pulses of stress. Smaller plants were nutrient limited under natural field conditions, suggesting that stress experienced during long interpulse phases may override competitive effects after short pulse phases. The observed differences in root system structure will determine when plants of a different species are experiencing a pulse or an interpulse phase. We suggest that the limitations to plant recruitment and growth are the product of a complex interplay between the length and intensity of the pulse of resource availability, the duration and severity of the interpulse periods, and biological characters of the species.

Exotic vs endemic biocontrol agents: Would the real stratiolaelaps miles (Berlese) (Acari : Mesostigmata : Laelapidae), please stand up?

The ability of introduced organisms to invade undisturbed native habitats is a major concern in conservation biology and has resulted in a re-evaluation of the introduction of exotic biocontrol agents, especially of generalist predators. One such agent is Stratiolaelaps miles (Berlese), a predatory mite described from Italy, known from throughout the Holarctic, and apparently accidentally introduced to other areas of the world, including Australia. Initial investigations revealed that putative S. miles could be found in both disturbed and relatively pristine habitats in Queensland, Australia. However, analysis of the mitochondrial DNA of five populations showed most to be highly divergent genetically. Subsequent morphological analysis established two species groups: the lamington-group from cool-temperate to subtropical rainforests in Eastern Australia and the more eurytopic miles-group with a cosmopolitan distribution. We describe two new species from each of these complexes (Stratiolaelaps womersleyi, Stratiolaelaps lamington; Stratiolaelaps marilyn, Stratiolaelaps lorna, respectively), and resurrect Stratiolaelaps scimitus (Womersley), a species which often appears to have been confused with S. miles. Additionally, the large genetic distances among morphologically homogenous species in the miles-group suggest that the apparently cosmopolitan S. miles may be composed of a suite of cryptic species of potentially varying utility in biological control. (C) 2002 Elsevier Science (USA). All rights reserved.

Genetic shifts in Helicoverpa armigera Hubner (Lepidoptera : Noctuidae) over a year in the Dawson/Callide Valleys

Microsatellites were used to analyse 68 collections of Helicoverpa armigera in the Dawson/Callide Valleys in central Queensland. The study aimed to evaluate the genetic structure in this region over a 12-month period (September 2000-August 2001). The results detected genetic shifts in H. armigera collections, with genetic changes occurring month by month. Collections in any month were genetically distant from the preceding month's collections. There was no observed difference between collections of H. armigera from the Biloela region and those found in the Theodore region of central Queensland. The data support the current area-wide management strategies for H. armigera by reinforcing the importance and contribution of local management practices. The study also indicates a need for the continuation of regional or Australia-wide approaches to management of the low levels of immigration that are occurring, and for future high pest pressure years.

Structure of the gut contents of Trichogramma australicum Girault (Hymenoptera : Trichogrammatidae) larvae fixed in situ in eggs of its host Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae)

Trichogramma australicum larvae develop most rapidly in younger eggs of its host, the pest lepidopteran Helicoverpa armigera . To establish how the developmental stage of the host affects the diet of T. australicum , larvae were fixed in situ in eggs of H. armigera of different ages and the structure of the egg contents and parasitoid gut contents examined histologically. Larvae feeding on newly laid host eggs contain primarily yolk particles in their gut, while larvae feeding on older hosts contain necrotic cells and yolk particles. The gut of T. australicum larvae does not contain organised tissue remnants, indicating that larvae feed primarily by sucking food into their pharynx and feed best on a mixture of particulate semisolids in a liquid matrix. Secretory structures of T. australicum larvae that could be involved in modifying the host environment were examined. The hindgut is modified to form an anal vesicle with a number of attributes suggesting that it may be a specialised secretory structure. The paired salivary glands open to the exterior via a common duct.

Modelling the size of the crushed zone around a blasthole

A new model to predict the extent of crushing around a blasthole is presented. The model is based on the back-analysis of a comprehensive experimental program that included the direct measurement of the zone of crushing from 92 blasting tests on concrete blocks using two commercial explosives. The concrete blocks varied from low, medium to high strength and measured 1.5 in in length, 1.0 m in width and 1.1 m in height. A dimensionless parameter called the crushing zone index (CZI) is introduced. This index measures the crushing potential of a charged blasthole and is a function of the borehole pressure, the unconfined compressive strength of the rock material, dynamic Young's modulus and Poisson's ratio. It is shown that the radius of crushing is a function of the CZI and the blasthole radius. A good correlation between the new model and measured results was obtained. A number of previously proposed models could not approximate the conditions measured in the experimental work and there are noted discrepancies between the different approaches reviewed, particularly for smaller diameter holes and low strength rock conditions. The new model has been verified with full scale tests reported in the literature. Results from this validation and model evaluations show its applicability to production blasting. (C) 2003 Elsevier Science Ltd. All rights reserved.

Differential modes of alaryngeal communication and long-term voice outcomes following pharyngolaryngectomy and laryngectomy

Patterns of vocal rehabilitation for 37 pharyngolaryngectomy patients and 55 total laryngectomy patients over a 5-year period were compared. An electrolarynx (EL) was introduced as the initial communication mode immediately after surgery for 98% of patients, with 30% of pharyngolaryngectomy and 74% of laryngectomy patients subsequently developing tracheoesophageal speech (TES) as their primary mode of communication. Follow-up with 14 of 37 pharyngolaryngectomy patients and 36 of 55 laryngectomy patients was conducted 1-6 years following surgery and revealed that 90% of the pharyngolaryngectomy patients maintained the use of TES in the long term compared to 69% of the laryngectomy group. Long-term outcomes relating to communication disability and handicap did not differ significantly between the two surgical groups, however the laryngectomy patients had significantly higher levels of wellbeing. Across the whole group of patients, statistical comparison revealed that patients using TES had significantly lower levels of disability, handicap and distress than EL users. Considering that lower levels of disability, handicap and distress are associated with TES, and the data supports that suitably selected patients can maintain functional TES in the long term, increased application of this form of communication rehabilitation should be encouraged where viable for the pharyngolaryngectomy population. Copyright (C) 2003 S. Karger AG, Basel.

Changes in postural stability in women aged 20 to 80 years

Background. A study of postural stability was undertaken to identify the relationship between vision and support surface across age decades. Understanding when reliance on vision for postural stability emerges and the support conditions contributing to this instability may provide the evidence required to introduce falls-prevention strategies in younger age decades. Methods. We measured postural stability in 453 women aged 20 to 80 years using the Balance Master force-plate system while the women performed the modified Clinical Test for the Sensory Interaction and Balance (firm and foam surfaces, eyes open and closed) and the Single-Limb Stance Test (eyes open and closed). Results. Women in their 60s and 70s were more unstable than younger women in bilateral stance on a firm surface with the eyes closed. This instability was evident from the 50s when a foam surface was introduced and from the 40s when single-limb stance was tested with eyes closed. A further decline in stability was demonstrated for each subsequent decade when the eyes were closed in single-limb stance. Conclusions. Age, visual condition, and support surface were significant variables influencing postural stability in women. Reliance on vision for postural stability was evident for women from the 40s when single-limb stance was tested, from the 50s when bilateral stance on foam was tested, and from the 60s when a firm surface was used. The cause(s) of this decline in stability requires further investigation, and screening for postural instability between the ages of 40 and 60 is advocated.

Kangaroos and feral goats as economic resources for graziers: Some views from south-west Queensland

Fifteen years ago it was proposed that the conversion of kangaroos from a pest to an economically valuable resource would allow graziers to reduce the numbers of domestic stock and thereby lower total grazing pressure. Since then, little progress towards this goal has been achieved. This is believed to be due mainly to the low prices obtained for kangaroo products. A survey of graziers in south-west Queensland was carried out to discover their opinions on kangaroos as a potential economic resource. Questions on the harvesting of feral goats were also included in the survey because of the contrast this industry provides to kangaroo harvesting in terms of grazier involvement. The results of the survey are discussed in relation to resource ownership rights; kangaroo product prices and marketing; and competition within the kangaroo harvesting industry. They show that while low kangaroo product prices do act as a disincentive to graziers, other administrative, legal and institutional factors are also important impediments to their entry to the industry. It is concluded that until the focus of attention widens to include consideration of these as well as just market factors, little progress will be made towards integrating graziers into the kangaroo harvesting industry.

Mean anisotropy of homogeneous Gaussian random fields and anisotropic norms of linear translation-invariant operators on multidimensional integer lattices

Sensitivity of output of a linear operator to its input can be quantified in various ways. In Control Theory, the input is usually interpreted as disturbance and the output is to be minimized in some sense. In stochastic worst-case design settings, the disturbance is considered random with imprecisely known probability distribution. The prior set of probability measures can be chosen so as to quantify how far the disturbance deviates from the white-noise hypothesis of Linear Quadratic Gaussian control. Such deviation can be measured by the minimal Kullback-Leibler informational divergence from the Gaussian distributions with zero mean and scalar covariance matrices. The resulting anisotropy functional is defined for finite power random vectors. Originally, anisotropy was introduced for directionally generic random vectors as the relative entropy of the normalized vector with respect to the uniform distribution on the unit sphere. The associated a-anisotropic norm of a matrix is then its maximum root mean square or average energy gain with respect to finite power or directionally generic inputs whose anisotropy is bounded above by a≥0. We give a systematic comparison of the anisotropy functionals and the associated norms. These are considered for unboundedly growing fragments of homogeneous Gaussian random fields on multidimensional integer lattice to yield mean anisotropy. Correspondingly, the anisotropic norms of finite matrices are extended to bounded linear translation invariant operators over such fields.

Database technologies for l-system simulations in virtual plant applications on bioinformatics

One of the most important advantages of database systems is that the underlying mathematics is rich enough to specify very complex operations with a small number of statements in the database language. This research covers an aspect of biological informatics that is the marriage of information technology and biology, involving the study of real-world phenomena using virtual plants derived from L-systems simulation. L-systems were introduced by Aristid Lindenmayer as a mathematical model of multicellular organisms. Not much consideration has been given to the problem of persistent storage for these simulations. Current procedures for querying data generated by L-systems for scientific experiments, simulations and measurements are also inadequate. To address these problems the research in this paper presents a generic process for data-modeling tools (L-DBM) between L-systems and database systems. This paper shows how L-system productions can be generically and automatically represented in database schemas and how a database can be populated from the L-system strings. This paper further describes the idea of pre-computing recursive structures in the data into derived attributes using compiler generation. A method to allow a correspondence between biologists' terms and compiler-generated terms in a biologist computing environment is supplied. Once the L-DBM gets any specific L-systems productions and its declarations, it can generate the specific schema for both simple correspondence terminology and also complex recursive structure data attributes and relationships.

The modeling of turbulent reactive flows based on multiple mapping conditioning

A new modeling approach-multiple mapping conditioning (MMC)-is introduced to treat mixing and reaction in turbulent flows. The model combines the advantages of the probability density function and the conditional moment closure methods and is based on a certain generalization of the mapping closure concept. An equivalent stochastic formulation of the MMC model is given. The validity of the closuring hypothesis of the model is demonstrated by a comparison with direct numerical simulation results for the three-stream mixing problem. (C) 2003 American Institute of Physics.

Complete genomic sequence of the Australian south-west genotype of Sindbis virus: Comparisons with other Sindbis strains and identification of a unique deletion in the 3 '-untranslated region

Our previous studies have shown that two distinct genotypes of Sindbis (SIN) virus occur in Australia. One of these, the Oriental/Australian type, circulates throughout most of the Australian continent, whereas the recently identified south-west (SW) genetic type appears to be restricted to a distinct geographic region located in the temperate south-west of Australia. We have now determined the complete nucleotide and translated amino acid sequences of a SW isolate of SIN virus (SW6562) and performed comparative analyses with other SIN viruses at the genomic level. The genome of SW6562 is 11,569 nucleotides in length, excluding the cap nucleotide and poly (A) tail. Overall this virus differs from the prototype SIN virus (strain AR339) by 23% in nucleotide sequence and 12.5% in amino acid sequence. Partial sequences of four regions of the genome of four SW isolates were determined and compared with the corresponding sequences from a number of SIN isolates from different regions of the World. These regions are the non-structural protein (nsP3), the E2 gene, the capsid gene, and the repeated sequence elements (RSE) of the 3'UTR. These comparisons revealed that the SW SIN viruses were more closely related to South African and European strains than to other Australian isolates of SIN virus. Thus the SW genotype of SIN virus may have been introduced into this region of Australia by viremic humans or migratory birds and subsequently evolved independently in the region. The sequence data also revealed that the SW genotype contains a unique deletion in the RSE of the 3'UTR region of the genome. Previous studies have shown that deletions in this region of the SIN genome can have significant effects on virus replication in mosquito and avian cells, which may explain the restricted distribution of this genotype of SIN virus.

Pasture grazing by black-striped wallabies (Macropus dorsalis) in central Queensland

Black-striped wallabies (Macropus dorsalis) are uncommon to rare in most of their former range, yet in parts of central Queensland where they are still locally common they are regarded as a serious pasture pest. There is considerable pressure from cattle graziers to reduce their density because of the putative damage that they cause to cattle pasture. Here we examined the effects of this species and other herbivores on pasture by monitoring vegetation cover between 1993 and 1998 in exclosures in brigalow, and poplar box communities on three grazing properties in the Maranoa region. The exclosures selectively allowed access to either: all vertebrate grazers including cattle; rabbits, bettongs, and wallabies; rabbits and bettongs; no vertebrate grazers. The greatest effects on the structure and species composition of pasture were caused by cattle, but wallabies did consume commercially important quantities of grass at some times of the year. This conflicts with local opinion that sees wallabies as the major cause of pasture degradation. Herein lies the management problem that sees continued reduction in wallaby habitat, and fragmentation of the species.