Analysis of diet and feeding strategies within an assemblage of estuarine larval fish and an objective assessment of dietary niche overlap

Fish larvae and zooplankton were sampled during seven consecutive months from four regions of Wilson Inlet, an estuary in south-western Australia. Mouth size, prey size, and dietary composition of larvae of the gobiids Afurcagobius suppositus, Pseudogobius olorum, and Favonigobius lateralis, the blenniid Parablennius tasmanianus, and the syngnathid Urocampus carinirostris were determined. Dietary niche overlap (DNO) was calculated for co-occurring species pairs, both with and without incorporating a measure of relative prey (zooplankton) abundance. Significance of DNO was assessed 1) objectively, with boot-strapping of the dietary data and 2) subjectively, by assigning significance to values >0.6. The diet of A. suppositus was dominated by harpacticoids, polychaete larvae, and the calanoid Gladioferens imparipes, whereas diets of the other species were dominated by copepod nauplii and postnaupliar stages of the cyclopoid Oithona simplex, the proportions of the latter increasing with growth of the larvae. Small numbers of large and small prey items were found in the stomachs of A. suppositus (mean=2.5), which had the largest mouth, whereas large numbers (mean= 28.7) of small prey and no large items were found in the stomachs of P. tasmanianus, which had the second largest mouth. Between these extremes, P. olorum, U. carinirostris, and F. lateralis each ate mostly small and intermediate-size prey, supplemented by a few large prey. The data did not support the hypothesis that an increase in the difference in gape size between species would decrease the prevalence of significant DNO. The lack of a consistent relation between mouth size and DNO among the five species is evidence that interspecific dietary differences reflect differences in feeding behavior. With bootstrapping, the prevalence of significant (P0.6, we obtained substantially less conservative estimates that indicated the prevalence of significant DNO was >53%

Factors required for the successful aquaculture of black bream (Acanthopagrus butcheri) in inland water bodies

The results of this project will contribute to the on-going development and success of inland black bream recreational fisheries and the inland saline aquaculture industry in general. Several commercial black bream fish-out ventures are now operational in inland Western Australia, one of which utilises saline groundwater. It has been proposed that a pilot project to stock the saline pools of the upper Avon River, which is located in the heart of the W.A. Wheatbelt, should be undertaken to provide recreational fishing opportunities for the inhabitants of a number of rural towns. The continued development of the W.A. inland saline aquaculture industry will result in social and economic benefits to rural areas through increased tourism and opportunities for farm diversification

Generalisation and optimisation of semi-active, on?off switching controllers for single degree-of-freedom systems

This paper examines generalised forms of semi-active switching control in comparison to the sky-hook semi-active controller. A switching time controller is proposed and analysed, in order to determine the optimal performance, with regard to displacement transmissibility, of semi-active switching control. In addition, the model is also used to assess the optimality of the sky-hook switching conditions. An analytical solution is then derived for the optimal switching times. A generalised form of linear switching surface controller is then presented. It is demonstrated that this controller can produce near optimal performance

Quasi-active suspension design using magnetorheological dampers

Quasi-active damping is a method of coupled mechanical and control system design using multiple semi-active dampers. By designing the systems such that the desired control force may always be achieved using a combination of the dampers, quasi-active damping seeks to approach levels of vibration isolation achievable through active damping, whilst retaining the desirable attributes of semi-active systems. In this article a design is proposed for a quasi-active, base-isolating suspension system. Control laws are firstly defined in a generalised form, where semi-active dampers are considered as idealised variable viscous dampers. This system is used to demonstrate in detail the principles of quasi-active damping, in particular the necessary interaction between mechanical and control systems. It is shown how such a system can produce a tunable, quasi-active region in the frequency response of very low displacement transmissibility. Quasi-active control laws are then proposed which are specific for use with magnetorheological dampers. These are validated in simulation using a realistic model of the damper dynamics, again producing a quasi-active region in the frequency response. Finally, the robustness of the magnetorheological, quasi-active suspension system is demonstrated. (C) 2010 Elsevier Ltd. All rights reserved

Unravelling social constructionism

Social constructionist research is an area of rapidly expanding influence that has brought together theorists from a range of different disciplines. At the same time, however, it has fuelled the development of a new set of divisions. There would appear to be an increasing uneasiness about the implications of a thoroughgoing constructionism, with some regarding it as both theoretically parasitic and politically paralysing. In this paper I review these debates and clarify some of the issues involved. My main argument is that social constructionism is not best understood as a unitary paradigm and that one very important difference is between what Edwards (1997) calls its ontological and epistemic forms. I argue that an appreciation of this distinction not only exhausts many of the disputes that currently divide the constructionist community, but also takes away from the apparent radicalism of much of this work

A nonlinear spring mechanism incorporating a bistable composite plate for vibration isolation

The High Static Low Dynamic Stiffness (HSLDS) concept is a design strategy for a nonlinear anti-vibration mount that seeks to increase isolation by lowering the natural frequency of the mount whilst maintaining the same static load bearing capacity. It has previously been proposed that an HSLDS mount could be implemented by connecting linear springs in parallel with the transverse flexure of a composite bistable plate — a plate that has two stable shapes between which it may snap. Using a bistable plate in this way will lead to lightweight and efficient designs of HSLDS mounts. This paper experimentally demonstrates the feasibility of this idea. Firstly, the quasi-static force–displacement curve of a mounted bistable plate is determined experimentally. Then the dynamic response of a nonlinear mass–spring system incorporating this plate is measured. Excellent agreement is obtained when compared to theoretical predictions based on the measured force–displacement curve, and the system shows a greater isolation region and a lower peak response to base excitation than the equivalent linear system

The first cyborg and First World War bodies as anti-war propaganda

This article discusses a play published in The Strand Magazine during the First World War which features a cyborg presenting anti-war and pacifist messages, used by The Strand to create anti-German propaganda. The article draws on theories of disability, cyborgs and the posthuman, and from new research on wartime fiction magazines. The importance of the cyborg character, Soldier 241, for the literary history of science fiction is explored by focusing on the relations between the mechanical and the impaired body, and on the First World War as a nexus for technological, surgical and military development. As a cyborg, this character reflects politicized desires that the wartime authorities did not acknowledge: a longing for the end of war, and refusal to countenance a society that rejected the impaired body

Learning through 'prosuming': Insights from media literacy programmes in Asia

10.1177/097172180801300205Science, Technology and Society132259-27

A discursive approach to narrative accounts of hearing voices and recovery

Substantive objective: To research the range of discursive constructions ‘recovered’ voice hearers employ to describe hearing voices and the implications for positioning and subjectivity (what can be thought and felt) using each construction. Methodological objective and method: To explore a ‘sympathetic’ application of Foucauldian discourse analysis, adapting Willig’s (2008 Willig, C. 2008. Introducing Qualitative Research in Psychology, Maidenhead: Open University Press. ) method, analysing two published accounts. Results and conclusions: Heterogeneous discursive constructions for talking about hearing voices were identified, including: ‘many-’selves’’, ‘taking-the-lead-in-your-own-recovery’, ‘voices-as-an-’imagined-world’’ and ‘voices-as-a-coping-strategy-for-dealing-with-trauma’. The discourse of the biomedical model was not prominent, suggesting alternate discursive constructions may create subjects with a greater capacity for ‘living with voices’ and create a subjectivity from which vantage point the experience holds meaning and value and can be integrated into life experiences. This research may have useful clinical applications for mental health services aiming to collaboratively explore service users’ ways of understanding hearing voices

Mathematical Aspects of the Periodic Law

We review different studies of the Periodic Law and the set of chemical elements from a mathematical point of view. This discussion covers the first attempts made in the 19th century up to the present day. Mathematics employed to study the periodic system includes number theory, information theory, order theory, set theory and topology. Each theory used shows that it is possible to provide the Periodic Law with a mathematical structure. We also show that it is possible to study the chemical elements taking advantage of their phenomenological properties, and that it is not always necessary to reduce the concept of chemical elements to the quantum atomic concept to be able to find interpretations for the Periodic Law. Finally, a connection is noted between the lengths of the periods of the Periodic Law and the philosophical Pythagorean doctrine.Comment: 20 pages, PDF fil