Physiological and morphological responses of the temperate seagrass Zostera muelleri to multiple stressors: investigating the interactive effects of light and temperature

Understanding how multiple environmental stressors interact to affect seagrass health (measured as morphological and physiological responses) is important for responding to global declines in seagrass populations. We investigated the interactive effects of temperature stress (24, 27, 30 and 32°C) and shading stress (75, 50, 25 and 0% shade treatments) on the seagrass Zostera muelleri over a 3-month period in laboratory mesocosms. Z. muelleri is widely distributed throughout the temperate and tropical waters of south and east coasts of Australia, and is regarded as a regionally significant species. Optimal growth was observed at 27°C, whereas rapid loss of living shoots and leaf mass occurred at 32°C. We found no difference in the concentration of photosynthetic pigments among temperature treatments by the end of the experiment; however, up-regulation of photoprotective pigments was observed at 30°C. Greater levels of shade resulting in high photochemical efficiencies, while elevated irradiance suppressed effective quantum yield (ΔF/FM'). Chlorophyll fluorescence fast induction curves (FIC) revealed that the J step amplitude was significantly higher in the 0% shade treatment after 8 weeks, indicating a closure of PSII reaction centres, which likely contributed to the decline in ΔF/FM' and photoinhibition under higher irradiance. Effective quantum yield of PSII (ΔF/FM') declined steadily in 32°C treatments, indicating thermal damage. Higher temperatures (30°C) resulted in reduced above-ground biomass ratio and smaller leaves, while reduced light led to a reduction in leaf and shoot density, above-ground biomass ratio, shoot biomass and an increase in leaf senescence. Surprisingly, light and temperature had few interactive effects on seagrass health, even though these two stressors had strong effects on seagrass health when tested in isolation. In summary, these results demonstrate that populations of Z. muelleri in south-eastern Australia are sensitive to small chronic temperature increases and light decreases that are predicted under future climate change scenarios.

Less is more: development and evaluation of an interactive e-atlas to support anatomy learning

An Interactive electronic Atlas (IeA) was developed to assist first-year nursing students with interpretation of laboratory-based prosected cadaveric material. It was designed, using pedagogically sound principles, as a student-centered resource accessible to students from a wide range of learning backgrounds. It consisted of a highly simplified interactive interface limited to essential anatomical structures and was intended for use in a blended learning situation. The IeA's nine modules mirrored the body systems covered in a Nursing Biosciences course, with each module comprising a maximum of 10 pages using the same template: an image displaying a cadaveric specimen and, in most cases, a corresponding anatomical model with navigation panes (menus) on one side. Cursor movement over the image or clicking the menu highlighted the structure with a transparent overlay and revealed a succinct functional description. The atlas was complemented by a multiple-choice database of nearly 1,000 questions using IeA images. Students' perceptions of usability and utility were measured by survey (n = 115; 57% of the class) revealing mean access of 2.3 times per week during the 12-week semester and a median time of three hours of use. Ratings for usability and utility were high, with means ranging between 4.24 and 4.54 (five-point Likert scale; 5 = strongly agree). Written responses told a similar story for both usability and utility. The role of providing basic computer-assisted learning support for a large first-year class is discussed in the context of current research into student-centered resources and blended learning in human anatomy.

Interactive television in schools : an Australian study of the tensions of educational technology and change

This paper outlines some key issues that arose from several projects that investigated the use of interactive television in schooling. In this paper we draw on these projects, to illustrate and discuss how a (then) new form of distance education -- satellite-based, narrowcast ITV -- was designated for use in primary (elementary) and secondary (high school) classroom settings, how it was implemented, and how it collapsed as an endeavour. Issues raised by students, teachers and administrators are related to each to illustrate how ITV slowly declined over several years, despite its usefulness for some and strong support from those involved.

Slurry pump side-liner wear : comparison of some laboratory and field results

The current work compares some slurry pump lab wear results with the wear found across different field applications with d₈₅ particle size ranging from 100 to 4000mm. Side-liner wear life data has been collected for two different impeller geometries and two different material classes (cast iron and natural rubber). Different field wear patterns have been photographed and categorised on the basis of particle size. The field wear patterns showed close similarity to the lab wear patterns particularly in the areas of localised gouging. Wear rates are also compared for the different geometries. Overall trend of wear with particle size for the white iron parts was similar to the grey iron lab tests albeit at significantly lower wear rates. In general, the wear with the rubber side-liner was less at smaller particle sizes but greater for particles larger than d8The current work compares some slurry pump lab wear results with the wear found across different field applications with d₈₅ particle 10 size ranging from 100 to 4000mm. Side-liner wear life data has been collected for two different impeller geometries and two different 11 material classes (cast iron and natural rubber). Different field wear patterns have been photographed and categorised on the basis of particle 12 size. The field wear patterns showed close similarity to the lab wear patterns particularly in the areas of localised gouging. Wear rates are 13 also compared for the different geometries. Overall trend of wear with particle size for the white iron parts was similar to the grey iron lab 14 tests albeit at significantly lower wear rates. In general, the wear with the rubber side-liner was less at smaller particle sizes but greater for 15 particles larger than d₈₅ of about 700mm. © 2001 Elsevier Science B.Y. All rights reserved.

Laboratory model studies of flushing of trapped salt water from a blocked tidal estuary

Results are presented from a series of laboratory model studies of the flushing of saline water from a partially- or fully-closed estuary. Experiments have been carried out to determine quantitatively the response of the trapped saline volume to fresh water flushing discharges Q for different values of the estuary bed slope α and the density difference (∆ρ)_o between the saline and fresh water. The trapped saline water forms a wedge within the estuary and for maintained steady discharges, flow visualisation and density profile data confirm that its response to the imposition of the freshwater purging flow occurs in two stages, namely (i) an initial phase characterised by intense shear-induced mixing at the nose of the wedge and (ii) a relatively quiescent second phase where the mixing is significantly reduced and the wedge is forced relatively slowly down and along the bed slope. Scalings based upon simple energy balance considerations are shown to be successful in (i) describing the time-dependent wedge behaviour and (ii) quantifying the proportion of input kinetic energy converted into increasing the potential energy of the wedge/river system. Measurements show that the asymptotic value of the energy conversion factor increases with increasing value of the river Froude number Fr_o at small values of Fr_o, thereafter reaching a maximum value and a gradual decrease at the highest values of Fr_o. Dimensional analysis considerations indicate that the normalised, time-dependent wedge position (x_w)³(g')o/q² can be represented empirically by a power-law relationship of the form (x_w)[(g')_o/q²]^1/3 =C [(t)[(g')_o²/q]^1/3]"where the proportionality coefficient C is a function of both Fr_o and the slope angle α and the exponent n has a value of 0.24. Successful attempts are made to relate the model data to existing field observations from a microtidal estuary.

Experiments with multiple, intermittent periodic flushing flows confirm the importance of the starting phase of each flushing event for the time dependent behaviour of the saline wedge after reaching equilibrium in the intervals between such events. For the parameter ranges investigated and for otherwise-identical external conditions, no significant differences are found in the position of the wedge between cases of sequential multiple flushing flows and steady single discharges of the same total duration.

Distance learning for laboratory practical work in microcontrollers

This paper presents a simple and relatively straightforward solution to the problems of equity in laboratory practical exposure between distance-education students and their traditional, on-campus, fellow cohort. This system has been implemented for the past five years in a university that is amongst the leaders in distance education delivery and has proved to be extremely successful and very well accepted by all students. While the intention was to allow distance education students easy access to the required laboratory practical content of the course, the solution found has proved to have many advantages for the on-campus students. Although this specific implementation is based upon microcontroller technology units in an engineering degree course, the methodology is easily transferable to other disciplines and courses.

Towards an interactive architecture for web-based databases

World Wide Web has brought us a lot of challenges, such as infinite contents, resource diversity, and maintenance and update of contents. Web-based database (WBDB) is one of the answers to these challenges. Currently the most commonly used WBDB architecture is three-tier architecture, which is still somehow lack of flexibility to adapt to frequently changed user requirements. In this paper, we propose a hybrid interactive architecture for WBDB based on the reactive system concepts. In this architecture, we use sensors to catch users frequently changed requirements and use a decision making manager agent to process them and generate SQL commands dynamically. Hence the efficiency and flexibility are gained from this architecture, and the performance of WBDB is enhanced accordingly.

Competitive interactions between the Australian native fish Galaxiasmaculatus and the exotic mosquitofish Gambusiaholbrooki,in a series of laboratory experiments

Competitive interactions between Galaxias maculatus, native to southeastern Australia, and Gambusia holbrooki, an exotic pest, were examined in relation to two types of artificial cover and a food source. Experiments were performed in an 800 l tank using photographic techniques. The relative distance of G. maculatus from cover or food source before and after the introduction of G. holbrooki were compared. Also, the proportions of the species were altered to examine the effects of unequal numbers on dominance behaviour. It was found that G. holbrooki was unable to out compete G. maculatus for either cover or food. The distance of G. maculatus from a food source was seen to increase following the introduction of G. holbrooki, when they outnumbered G. maculatus by 3 to 1. Although the distance from the food of G.maculatus increased following the introduction of G. holbrooki, in all cases the mean distance of G.␣maculatus from cover or food was less than that of G. holbrooki. Significant intra-species competition appeared to occur between G. maculatus and it may be that this competition had a greater effect than the competitive pressure G. holbrooki was able to place on the natives. This study revealed that the exotic pest species, G. holbrooki, could not out compete a small native Australian fish species.

Mobile Architecture and Built Environment Laboratory (MABEL) - a building performance evaluation tool

This paper describes the Mobile Architecture and Built Environment Laboratory (MABEL) and its application for systematic building performance evaluation for compliance testing, commissioning, strategic and operational facility management and continuous improvement in the built environment.

The first part of the paper introduces the application areas of on-site building performance evaluation and discusses the shortcomings in this regard in current practice. It emphasises the need for on-site investigations to generate information on 'as built performance' for the 'feedback' loop between design, operation and occupancy of new buildings, retrofit or adjustment.

The second part introduces the Energy-Comfort-Behaviour Framework for 'across-the-board' building evaluation and discusses MABEL's role in this scheme. MABEL's objectives, procedures and the performance measurement matrix are explained and discussed.

An ecobehavioural analysis of interactive engagement of children with developmental disabilities with their peers in inclusive preschools

Ecobehavioural analysis procedures were used to examine the interactive engagement of children with developmental disabilities due to Down syndrome who attended inclusive preschools for 2 years. Compared with typical children, the children with disabilities displayed infrequent interactions with peers for the duration of the study. For the children with disabilities, interactive engagement was largely unrelated to the characteristics of class activities, while typical children responded positively to activities expected to promote peer interaction. The results are discussed in terms of the inadequacy of informal strategies commonly applied in inclusive preschool settings to promote interactive engagement in children with disabilities.

Usability and learning in online environments : a case of interactive encounters

This paper proposes a set of strategies to maximise learner-content and learner-learner interactions in on-line learning environments. Extrapolating the outcomes of a research study that investigated the ways in which users responded to the interactive constructs embedded within interactive multimedia applications, the concept of encounter theory is introduced. Using observation and interview techniques, participants in the study identified a range of options by which learnercomputer interactions might be enhanced. The implications of these findings for online and desktop environments are considered, specifically in terms of the independent learner's encounter with content material and other learners. Developing a comprehensive understanding of the interactive phenomenon will not only lead to more effective useability and learning in on-line environments, but also to their working better for the learner.

A case for a mobile architecture and built environment laboratory

Deakin University and other research and industry partners have recently won a grant for the establishment of a Mobile Architecture and Built Environment Laboratory (MABEL). MABEL provides the first means of integrated, on-site measurement of the key aspects of the built environment (power, sound, light and comfort) using the latest instrument technology. There exists an ongoing need to establish a versatile and comprehensive in-situ testing facility for built internal environments, for the provision of research, education, training and technology diffusion. The ability to make on-site measurements across the environmental spectrum is unique and important. Individual measurements might demonstrate improved lighting performance, reduced power consumption, and improved ventilation or better building acoustics. More importantly, an integrated perspective will address an interaction in terms of energy efficiency and overall occupant comfort. H is recognised that many of the parameters we can measure with existing instrumentation remain unresolved regarding their diagnostic significance on occupant health, comfort and productivity. Also, developed standards for in-situ measurement are at an emerging state, in the delivery of reliable and useful assessment methods. This paper discusses the inception and role of the MABEL facility for building research, learning and teaching.

Poesis in diegesis : real-time interactive dance performance

This paper describes the processes of creating a hybrid experience of live performance and virtual imagery in 1 + x: Mid-range Projections, a dance work that uses real-time processing of live feed video to create a duet between dancers and their virtual images. 1 + x is about creating experiences of interiority and intimacy, ironically, through the juxtaposition of virtual images of performers with their real selves. This paper examines how the ideal of reinserting intimacy, humanity and 'presence' into a technologically generated image space, in the case of 1 + x, depends on the precise and delicate manipulation of live-feed video in collaboration with the audience's experience of interactivity. The result is a performance work that creates a poesis of 'presence', through a diegesis that melds real and virtual images on the same screen and the same conceptual and spatial plane - a 'becoming virtual'.