Optimal patch-leaving behaviour: a case study using the parasitoid Cotesia rubecular

1. Parasitoids are predicted to spend longer in patches with more hosts, but previous work on Cotesia rubecula (Marshall) has not upheld this prediction, Tests of theoretical predictions may be affected by the definition of patch leaving behaviour, which is often ambiguous. 2. In this study whole plants were considered as patches and assumed that wasps move within patches by means of walking or flying. Within-patch and between-patch flights were distinguished based on flight distance. The quality of this classification was tested statistically by examination of log-survivor curves of flight times. 3. Wasps remained longer in patches with higher host densities, which is consistent with predictions of the marginal value theorem (Charnov 1976). tinder the assumption that each flight indicates a patch departure, there is no relationship between host density and leaving tendency. 4. Oviposition influences the patch leaving behaviour of wasps in a count down fashion (Driessen et al. 1995), as predicted by an optimal foraging model (Tenhumberg, Keller & Possingham 2001). 5. Wasps spend significantly longer in the first patch encountered following release, resulting in an increased rate of superparasitism.

China and Southeast Asia

In the new millennium, no issue in international relations will be more important than how to accommodate the rising power of China. Many analysts, especially in the United States, see China as a significant threat to American interests in Asia. Washington has treaty commitments in both Northeast and Southeast Asia and retains a substantial military presence in the region. Beijing claims it does not seek to replace the United States reigning global hegemony, but seeks to promote a multi-polar world in which six states (the US, China, the EU, Russia, Japan, and India) would have pre-eminent status.

Demography of bridled nailtail wallabies translocated to the edge of their former range from captive and wild stock

Despite numerous, generally unsuccessful attempts to reintroduce threatened Australian mammals, the factors leading to their failure have not been fully clarified, although predator control would appear to be of paramount importance. An experimental approach was taken in attempting to establish a population of bridled nailtail wallabies ih an area of apparently suitable habitat and low fox density, but on the edge of the species' former range. The 133 wallabies released since late 1996 comprised four groups captive-bred animals, wild caught from the single remaining wild population, animals that were captive bred and acclimatised at the translocation site in a 10 ha predator-proof enclosure, and animals which had been bred in the enclosure. Survival was highest in those bred in the enclosure and highly variable among captive-bred animals. Survival estimates for wild recruits suggested the population would maintain a positive rate of increase under prevailing environmental conditions. Spotlighting surveys suggested the population had increased to approximately 400 animals by late 1999. Above average rainfall during 1996-1999 and no apparent predation suggests caution in describing the translocation as a success. Ongoing monitoring is critical, because it A uncertain ho v the population will cope with drought and inevitable predation events, and whether the population will expand and persist outside of limited preferred habitat. (C) 2001 Elsevier Science Ltd. All rights reserved.

Curriculum development for professional ethics in Australian human service university programmes

Australian academics and practitioners in the human services are particularly susceptible to social, political and economic influences in respect of their relevance, viability and operations. In fact, it can be argued that the impact of these influences has placed human service practitioners and academics in a perpetual state of vulnerability. Australian universities have been challenged to make their programmes more relevant and viable to the community at large, and practitioners face increasing workloads with limited resources based on restricted fiscal allocation, and the changing relationship between government and service providers. Drawing on interview data from twenty-one (n = 21) practitioners, this article highlights their identified problems regarding the notion of professionalism in the human services with a particular focus on ethical dilemmas in human service practice. Gleaning these details will be a basis for recommending necessary professionalethics curricula content in human services programmes offered in Australian universities. Moreover, while the research data is Australian based, the authors contend that the universal theories and principles underpinning human service practice justify the significance and value of the data as an important source for international consideration in curriculum development of human service academic programmes.

Comparative phylogeography of three rainforest-restricted lizards from mid-east Queensland

Several small isolates of rainforest situated on the central eastern coast of Australia are home to a rich herpetofauna, including four endemic species of leaftail geckos (Phyllurus spp.) and two skinks (Eulamprus spp.). To examine the extent and geographic pattern of historical subdivision among isolates, we assayed mtDNA variation in two species endemic to rainforests of this region (Phyllurus ossa and Eulamprus amplus) and, for comparison, a more widespread and less specialised lizard, Carlia rhomboidalis. There is a clear genetic signature of historical changes in population size and distribution in P. ossa that is consistent with Pleistocene (or earlier) rainforest contraction and subsequent expansion. Although more pronounced in the gecko, phylogeographic structure was congruent between E. amplus and P. ossa. In contrast to the saxicolous, rainforest-restricted P. ossa and E. amplus, the rainforest-generalist species, C. rhomboidalis, does not display strong geographic population structure. The differences in genetic population structure exhibited by the three species are consistent with species-specific differences in ecology.

The natural history of Hendra and Nipah viruses

Pteropid bats (flying foxes), species of which are the probable natural host of both Hendra and Nipah viruses, occur in overlapping populations from India to Australia. Ecological changes associated with land use and with animal husbandry practices appear most likely to be associated with the emergence of these two agents. (C) 2001 Editions scientifiques et medicales Elsevier SAS.

Primary fallopian tube carcinoma: the Queensland experience

The purpose of this study was to review the experience with fallopian tube carcinoma in Queensland and to compare it with previously published data. Thirty-six patients with primary fallopian tube carcinoma treated at the Queensland Gynaecological Cancer Center from 1988 to 1999 were reviewed in a retrospective clinicopathologic study. All patients had primary surgery and 31/36 received chemotherapy postoperatively. Abnormal vaginal bleeding (15/36) and abdominal pain (14/36) were the most common presenting symptoms at the time of diagnosis. Median follow-up was 70.3 months and the median overall survival was 68.1 months. Surgical stage I disease (P = 0.02) and the absence of residual tumor after operation (P = 0.03) were the only factors associated with improved survival. Twenty of the 36 patients (55%) presented with stage I disease and survival was 62.7% at 5 years. No patient with postoperative residual tumor survived. The majority of the patients with fallopian tube carcinoma present with stage I disease at diagnosis, but their survival probability is low compared with that of other early stage gynecological malignancies. If primary surgical debulking cannot achieve macroscopic tumor clearence, the chance of survival is extremely low.

Human cortical processing of colour and pattern

The present study investigates human visual processing of simple two-colour patterns using a delayed match to sample paradigm with positron emission tomography (PET). This study is unique in that we specifically designed the visual stimuli to be the same for both pattern and colour recognition with all patterns being abstract shapes not easily verbally coded composed of two-colour combinations. We did this to explore those brain regions required for both colour and pattern processing and to separate those areas of activation required for one or the other. We found that both tasks activated similar occipital regions, the major difference being more extensive activation in pattern recognition. A right-sided network that involved the inferior parietal lobule, the head of the caudate nucleus, and the pulvinar nucleus of the thalamus was common to both paradigms. Pattern recognition also activated the left temporal pole and right lateral orbital gyrus, whereas colour recognition activated the left fusiform gyrus and several right frontal regions. (C) 2001 Wiley-Liss, Inc.

Field quantization, photons and non-Hermitean modes

Field quantization in unstable optical systems is treated by expanding the vector potential in terms of non-Hermitean (Fox-Li) modes. We define non-Hermitean modes and their adjoints in both the cavity and external regions and make use of the important bi-orthogonality relationships that exist within each mode set. We employ a standard canonical quantization procedure involving the introduction of generalized coordinates and momenta for the electromagnetic (EM) field. Three-dimensional systems are treated, making use of the paraxial and monochromaticity approximations for the cavity non-Hermitean modes. We show that the quantum EM field is equivalent to a set of quantum harmonic oscillators (QHOs), associated with either the cavity or the external region non-Hermitean modes, and thus confirming the validity of the photon model in unstable optical systems. Unlike in the conventional (Hermitean mode) case, the annihilation and creation operators we define for each QHO are not Hermitean adjoints. It is shown that the quantum Hamiltonian for the EM field is the sum of non-commuting cavity and external region contributions, each of which can be expressed as a sum of independent QHO Hamiltonians for each non-Hermitean mode, except that the external field Hamiltonian also includes a coupling term responsible for external non-Hermitean mode photon exchange processes. The non-commutativity of certain cavity and external region annihilation and creation operators is associated with cavity energy gain and loss processes, and may be described in terms of surface integrals involving cavity and external region non-Hermitean mode functions on the cavity-external region boundary. Using the essential states approach and the rotating wave approximation, our results are applied to the spontaneous decay of a two-level atom inside an unstable cavity. We find that atomic transitions leading to cavity non-Hermitean mode photon absorption are associated with a different coupling constant to that for transitions leading to photon emission, a feature consequent on the use of non-Hermitean mode functions. We show that under certain conditions the spontaneous decay rate is enhanced by the Petermann factor.

A molecular phylogeny of rainbow skinks (Scincidae : Carlia): taxonomic and biogeographic implications

The phylogenetic relationships amongst 29 species of Carlia and Lygisaurus were estimated using a 726-base-pair segment of the protein-coding mitochondrial ND4 gene. Results do not support the recent resurrection of the genus Lygisaurus. Although most Lygisaurus species formed a single clade, this clade is nested within Carlia and includes Carlia parrhasius. Due to this new molecular evidence, and the paucity of diagnostic morphological characters separating the genera, Lygisaurus de Vis 1884 is re-synonymised with Carlia Gray 1845. Our analysis is also inconsistent with a previous suggestion that Lygisaurus timlowi should be removed to Menetia, a genus that is distantly related relative to outgroups used here. Intraspecific variation in Carlia is, in several instances, greater than interspecific distance. The most strikingly divergent lineages are found within C. rubrigularis, which appears to be paraphyletic, with southern populations more closely related to C. rhomboidalis than to northern populations of C. rubrigularis. The two C. rubrigularis-C. rhomboidalis lineages form part of a major polytomy at an intermediate level of divergence. Lack of resolution at this level, however, does not appear to be due to saturation or loss of phylogenetic signal. Rather, the polytomy probably reflects a period of relatively rapid diversification that occurred sometime during the Miocene.

Effect of the movement speed of resistance training exercises on sprint and strength performance in concurrently training elite junior sprinters

The aim of this study was to determine the effects of 7 weeks of high- and low-velocity resistance training on strength and sprint running performance in nine male elite junior sprint runners (age 19.0 +/- 1.4 years, best 100 m times 10.89 +/- 0.21 s; mean +/- s). The athletes continued their sprint training throughout the study, but their resistance training programme was replaced by one in which the movement velocities of hip extension and flexion, knee extension and flexion and squat exercises varied according to the loads lifted (i.e. 30-50% and 70-90% of 1-RM in the high- and low-velocity training groups, respectively). There were no between-group differences in hip flexion or extension torque produced at 1.05, 4.74 or 8.42 rad . s(-1), 20 m acceleration or 20 m 'flying' running times, or 1-RM squat lift strength either before or after training. This was despite significant improvements in 20 m acceleration time (P < 0.01), squat strength (P< 0.05), isokinetic hip flexion torque at 4.74 rad . s(-1) and hip extension torque at 1.05 and 4.74 rad . s(-1) for the athletes as a whole over the training period. Although velocity-specific strength adaptations have been shown to occur rapidly in untrained and non-concurrently training individuals, the present results suggest a lack of velocity-specific performance changes in elite concurrently training sprint runners performing a combination of traditional and semi-specific resistance training exercises.

Simulation of insect movement with respect to plant architecture and morphogenesis

Developments in computer and three dimensional (3D) digitiser technologies have made it possible to keep track of the broad range of data required to simulate an insect moving around or over the highly heterogeneous habitat of a plant's surface. Properties of plant parts vary within a complex canopy architecture, and insect damage can induce further changes that affect an animal's movements, development and likelihood of survival. Models of plant architectural development based on Lindenmayer systems (L-systems) serve as dynamic platforms for simulation of insect movement, providing ail explicit model of the developing 3D structure of a plant as well as allowing physiological processes associated with plant growth and responses to damage to be described and Simulated. Simple examples of the use of the L-system formalism to model insect movement, operating Lit different spatial scales-from insects foraging on an individual plant to insects flying around plants in a field-are presented. Such models can be used to explore questions about the consequences of changes in environmental architecture and configuration on host finding, exploitation and its population consequences. In effect this model is a 'virtual ecosystem' laboratory to address local as well as landscape-level questions pertinent to plant-insect interactions, taking plant architecture into account. (C) 2002 Elsevier Science B.V. All rights reserved.