Relationship between oviposition preference and offspring performance in Australian Helicoverpa armigera (Hubner) (Lepidoptera : Noctuidae)

We investigated the oviposition preference and larval performance of Helicoverpa armigera under laboratory conditions to determine if the oviposition preference of individual females on maize, cowpea and cotton correlates with offspring performance on the leaves of the same host plants. The host-plant preference hierarchy of females did not correlate with their offspring performance. Female moths chose host plants that contributed less to their offspring fitness. Plant effects accounted for the largest amount of variation in offspring performance, while the effects of female (family) was low. The offspring of most females (80%, n = 10) were broadly similar, but 20% (two out of 10), showed marked difference in their offspring performance across the host-plant species. Similarly, there was no relation between larval feeding preference and performance. However, like most laboratory experiments, our experi-mental design does not allow the evaluation of ecological factors (for example, natural enemies, host abundance, etc.) that can play an important role in larval performance in the field. Overall, the results highlight the importance of carrying out preference performance analysis on the individual or family level, rather than pooling individuals to obtain average population data.

Defining quality of life for Chinese elderly stroke survivors

Purpose: This study aimed to identify the constituents and conceptual characteristics of the quality of life (QOL) of Chinese elderly stroke survivors. living in the community in Hong Kong. Method: A triangulated approach was used to identify the QOL components for this population. This process involved a comparison of QOL components gathered from three different methods, namely, focus group interviews, review of the literature and the contents of the generic Hong Kong Chinese version of the World Health Organization Quality of Life Scale (CWHOQOL-HK). Five health professionals were involved in the comparison process. A percentage of inter-judge agreement was used to determine the reliability of the comparisons made between the judges. Results: This study identified 36 components considered to contribute to the QOL of Chinese elderly stroke survivors in Hona Kong. The conceptual characteristics of their QOL generally concurred with those identified in the literature. Conclusion: Both similarities and differences were found in the QOL components identified in this study when compared to those identified in studies of Western populations who are elderly and had a stroke. The contents of the CWHOQOL-HK scale were found to lack adequacy in representing the QOL of Chinese elderly stroke survivors in Hong Kong. Recommendations are given, based on the findings of this study, to overcome this limitation for its application as a QOL measure for this population.

Principles versus artifacts in computer science curriculum design

Computer Science is a subject which has difficulty in marketing itself. Further, pinning down a standard curriculum is difficult-there are many preferences which are hard to accommodate. This paper argues the case that part of the problem is the fact that, unlike more established disciplines, the subject does not clearly distinguish the study of principles from the study of artifacts. This point was raised in Curriculum 2001 discussions, and debate needs to start in good time for the next curriculum standard. This paper provides a starting point for debate, by outlining a process by which principles and artifacts may be separated, and presents a sample curriculum to illustrate the possibilities. This sample curriculum has some positive points, though these positive points are incidental to the need to start debating the issue. Other models, with a less rigorous ordering of principles before artifacts, would still gain from making it clearer whether a specific concept was fundamental, or a property of a specific technology. (C) 2003 Elsevier Ltd. All rights reserved.

Life cycle evolution in the Digenea: a new perspective from phylogeny

We use a new molecular phylogeny, developed from small and large subunit ribosomal RNA genes, to explore evolution of the digenean life cycle. Our approach is to map character states on the phylogeny and then use parsimony to infer how the character evolved. We conclude that, plesiomorphically, digenean miracidia hatched from eggs and penetrated gastropod first intermediate hosts externally. Fork-tailed cercariae were produced in rediae and emerged from the snail to be eaten directly by the teleost definitive host. These plesiomorphic characters are seen in extant Bivesiculidae. We infer that external encystment and the use of second intermediate hosts are derived from this behaviour and that second intermediate hosts have been adopted repeatedly. Tetrapod definitive hosts have also been adopted repeatedly. The new phylogeny proposes a basal dichotomy between 'Diplostomida' (Diplostomoidea, Schistosomatoidea and Brachylaimoidea) and 'Plagiorchiida' (all other digeneans). There is no evidence for coevolution between these clades and groups of gastropods. The most primitive life cycles are seen in basal Plagiorchiida. Basal Diplostomida have three-host life cycles and are associated with tetrapods. The blood flukes (Schistosomatoidea) are inferred to have derived their two-host life cycles by abbreviating three-host cycles. Diplostomida have no adult stages in fishes except by life cycle abbreviation. We present and test a radical hypothesis that the blood-fluke cycle is plesiomorphic within the Diplostomida.

Phylogenetic relationships of Hepatozoon (Haemogregarina) boigae Hepatozoon sp. Haemogregarina clelandi and Haemoproteus chelodina from Australian reptiles to other Apicomplexa based on cladistic analyses of ultrastructural and life-cycle characters

The phylogeny of representative haemozoan species of the phylum Apicomplexa was reconstructed by cladistic analyses of ultrastructural and life-cycle characteristics. The analysis incorporated 4 apicomplexans previously not included in phylogenetic reconstructions: Haemogregarina clelandi from the Brisbane River tortoise (Emydura signata), Hepatozoon sp. from the slaty grey snake (Stegonotus cucullatus), Hepatozoon (Haemogregarina) boigae from the brown tree snake (Boiga irregularis), and Haemoproteus chelodina from the saw-shelled tortoise (Elseya latisternum). There was no apparent correlation between parasite phylogeny and that of their vertebrate hosts, but there appeared to be some relationship between parasites and their intermediate hosts, suggestive of parasite/vector co-evolution.

Blast design using measurement while drilling parameters

Measurement while drilling (MWD) techniques can provide a useful tool to aid drill and blast engineers in open cut mining. By avoiding time consuming tasks such as scan-lines and rock sample collection for laboratory tests, MWD techniques can not only save time but also improve the reliability of the blast design by providing the drill and blast engineer with the information specially tailored for use. While most mines use a standard blast pattern and charge per blasthole, based on a single rock factor for the entire bench or blast region, information derived from the MWD parameters can improve the blast design by providing more accurate rock properties for each individual blasthole. From this, decisions can be made on the most appropriate type and amount of explosive charge to place in a per blasthole or to optimise the inter-hole timing detonation time of different decks and blastholes. Where real-time calculations are feasible, the system could extend the present blast design even be used to determine the placement of subsequent holes towards a more appropriate blasthole pattern design like asymmetrical blasting.

Asymmetric blasting: a rock mass dependent blast design method

Blasting has been the most frequently used method for rock breakage since black powder was first used to fragment rocks, more than two hundred years ago. This paper is an attempt to reassess standard design techniques used in blasting by providing an alternative approach to blast design. The new approach has been termed asymmetric blasting. Based on providing real time rock recognition through the capacity of measurement while drilling (MWD) techniques, asymmetric blasting is an approach to deal with rock properties as they occur in nature, i.e., randomly and asymmetrically spatially distributed. It is well accepted that performance of basic mining operations, such as excavation and crushing rely on a broken rock mass which has been pre conditioned by the blast. By pre-conditioned we mean well fragmented, sufficiently loose and with adequate muckpile profile. These muckpile characteristics affect loading and hauling [1]. The influence of blasting does not end there. Under the Mine to Mill paradigm, blasting has a significant leverage on downstream operations such as crushing and milling. There is a body of evidence that blasting affects mineral liberation [2]. Thus, the importance of blasting has increased from simply fragmenting and loosing the rock mass, to a broader role that encompasses many aspects of mining, which affects the cost of the end product. A new approach is proposed in this paper which facilitates this trend 'to treat non-homogeneous media (rock mass) in a non-homogeneous manner (an asymmetrical pattern) in order to achieve an optimal result (in terms of muckpile size distribution).' It is postulated there are no logical reasons (besides the current lack of means to infer rock mass properties in the blind zones of the bench and onsite precedents) for drilling a regular blast pattern over a rock mass that is inherently heterogeneous. Real and theoretical examples of such a method are presented.

Effectiveness of case management and post-acute services in older people after hospital discharge

Objective: To evaluate the benefits of coordinating community services through the Post-Acute Care (PAC) program in older patients after discharge from hospital. Design: Prospective multicentre, randomised controlled trial with six months of follow-up with blinded outcome measurement. Setting: Four university-affiliated metropolitan general hospitals in Victoria. Participants: All patients aged 65 years and over who were discharged between August 1998 and October 1999 and required community services after discharge. Interventions: Participants were randomly allocated to receive services of a Post-Acute Care (PAC) coordinator (intervention) versus usual discharge planning (control). Main outcome measures: Comparison of quality of life and carer stress at one-month post-discharge, mortality, hospital readmissions, use of community services and community and hospital costs over the six months post-discharge. Results: 654 patients were randomised, and 598 were included in the analysis (311 in the PAC group and 287 in the control group). There was no difference in mortality between the groups (both 6%), but significantly greater overall quality-of-life scores at one-month follow-up in the PAC group. There was no difference in unplanned readmissions, but PAC patients used significantly fewer hospital bed-days in the six months after discharge (mean, 3.0 days; 95% CI, 2.1-3.9) than control patients (5.2 days; 95% CI, 3.8-6.7). Total costs (including hospitalisation, community services and the intervention) were lower in the PAC than the control group (mean difference, $1545; 95% CI, $11-$3078). Conclusions: The PAC program is beneficial in the transition from hospital to the community in older patients.