A new light on sex: signalling in the guppy

The environment influences the evolution of animal colour signals in highly complex ways. This PhD identified the effects of varying light environments on the evolution of colour signals, identified behaviours that are able to mitigate these effects and demonstrated co-option as a potential origin of colour sexual signals.

Variable environmental effects on a multicomponent sexually selected trait

Multicomponent signals are made up of interacting elements that generate a functional signaling unit. The interactions between signal components and their effects on individual fitness are not well understood, and the effect of environment is even less so. It is usually assumed that color patterns appear the same in all light environments and that the effects of each color are additive. Using guppies, Poecilia reticulata, we investigated the effect of water color on the interactions between components of sexually selected male coloration. Through behavioral mate choice trials in four different water colors, we estimated the attractiveness of male color patterns, using multivariate fitness estimates and overall signal contrast. Our results show that females exhibit preferences that favor groups of colors rather than individual colors independently and that each environment favors different color combinations. We found that these effects are consistent with female guppies selecting entire color patterns on the basis of overall visual contrast. This suggests that both individuals and populations inhabiting different light environments will be subject to divergent, multivariate selection. Although the appearance of color patterns changes with light environment, achromatic components change little, suggesting that these could function in species recognition or other aspects of communication that must work across environments. Consequently, we predict different phylogenetic patterns between chromatic and achromatic signals within the same clades.

Color signals in the Black Grouse (Tetrao tetrix) : signal properties and their condition dependency

Recent progress in techniques of quantifying between‐individual differences of color‐based ornaments has revealed undiscovered possibilities for research in sexual selection. We present how the color spectra data can be comprehensively used for studying the importance of sexual ornaments in the black grouse and how these ornaments are related to a male condition. For this, we used both correlative field and experimental data. Field data indicated that older males had more chromatic coloration than yearlings. Blue chroma of males was correlated with male mating success. We experimentally manipulated yearling birds with testosterone implants and found that testosterone‐implanted males had impaired expression of several sexual ornaments: 10 months after the implantation, both structural‐based blue and carotenoid‐based red eye comb coloration were diminished, as well as lyre (tail) length. However, the manipulation did not affect vital traits under natural selection (wing length or body mass). Our data indicate that structural color is an important trait in sexual selection in this lekking species. Importantly, the data also indicate that male sexual ornaments are more susceptible to environmental conditions than the other male traits, thus showing their heightened condition dependency compared with the other traits mediating the honesty of signaling.

Prenatal environmental effects match offspring begging to parental provisioning

The solicitation behaviours performed by dependent young are under selection from the environment created by their parents, as well as wider ecological conditions. Here we show how mechanisms acting before hatching enable canary offspring to adapt their begging behaviour to a variable post-hatching world. Cross-fostering experiments revealed that canary nestling begging intensity is positively correlated with the provisioning level of their own parents (to foster chicks). When we experimentally increased food quality before and during egg laying, mothers showed higher faecal androgen levels and so did their nestlings, even when they were cross-fostered before hatching to be reared by foster mothers that had been exposed to a standard regime of food quality. Higher parental androgen levels were correlated with greater levels of post-hatching parental provisioning and (we have previously shown) increased faecal androgens in chicks were associated with greater begging intensity. We conclude that androgens mediate environmentally induced plasticity in the expression of both parental and offspring traits, which remain correlated as a result of prenatal effects, probably acting within the egg. Offspring can thus adapt their begging intensity to variable family and ecological environments.

Environmental efficiency : meaning and measurement and application to Australian dairy farms

Technical efficiency has been widely studied in the literature, but in its pursuit, many of the inputs used can impact on the environment. Environmental effects can be modelled as undesirable output or, as has been the case in more recent studies, as conventional inputs. This paper examines the concept of environmental efficiency and how it can be used to evaluate the performance of Australian dairy farming, using nitrogen surplus, arising from excessive applications of fertilizer, as a detrimental input. Farming promotes the image of clean and green production and if this image is to be maintained, there is a need to ensure activities are environmentally friendly.

Genetic and environmental influences on variation in balance performance among female twin pairs aged 21-82 years

Genetic and environmental influences on variation in balance performance were measured in 93 monozygous and 83 dizygous female twin pairs aged 21–82 years (mean age, 50.5 years) in Melbourne, Australia, between 1999 and 2003. The authors administered clinical (Lord's Balance Test and Step Test) and laboratory tests of static and dynamic balance from the Chattecx Balance System with and without distractor tasks. The authors conducted factor analysis and estimated genetic and environmental variance components and heritability (defined as additive genetic variance as a proportion of all variance, after adjustment for age) using a multivariate normal model with the statistical package FISHER. Three factors were identified and adjusted for age. Heritability was 46% (standard error (SE), 9) for the "sensory balance tests" factor and 30% (SE, 9) for the "static and dynamic perturbations" factor. For both factors, the remaining variance was attributed to unique environmental effects. There was no evidence that genetic factors influenced variation in the "dynamic weight shift tests" factor, with environmental effects shared by twins accounting for 38% (SE, 7) of variance. Neither genetic nor environmental proportions of variance differed significantly between twin subgroups by age (≤50/>50 years). An age-related decline in performance measures was found across the whole sample. These results imply that balance impairments may have a heritable element.

Fuzzy simulation of pedestrian walking path considering local environmental stimuli

Pedestrian steering activity is a perception-based decision making process that involves interaction with the surrounding environment and insight into environmental stimuli. There are many stimuli within the environment that influence pedestrian wayfinding behaviour during walking activities. However, compelling factors such as individual physical and psychological characteristics and trip intention cause the behaviour become a very fuzzy concept. In this paper pedestrian steering behaviour is modelled using a fuzzy logic approach. The objective of this research is to simulate pedestrian walking paths in indoor public environments during normal and non-panic situations. The proposed algorithm introduces a fuzzy logic framework to predict the impact of perceived attractive and repulsive stimuli, within the pedestrian's field of view, on movement direction. Environmental stimuli are quantified using the social force method. The algorithm is implemented in a simulated area of an office corridor consist of a printer and exit door. Stochastic simulation using the proposed fuzzy algorithm generated realistic walking trajectories, contour map of dynamic change of environmental effects in each step of movement and high flow areas in the corridor.

Beliefs about genetically modified foods : a qualitative and quantitative exploration

This study is aimed to examine consumers' beliefs about genetically modified foods. Ten focus group interviews of community members and a random questionnaire-based mail survey of 500 Australian (Victorian) adults were conducted (58% response). Participants were generally negative about genetically modified foods, with concerns being raised about them being unnatural, difficult to identify, and having unknown long-term health and environmental effects. Many participants were unaware of or disagreed with the benefits of genetically modified foods that are promoted by its advocates and there were some misconceptions present. These findings provide information for both advocates and opponents of genetically modified foods and a basis for future larger-scale research.

Making long-term economic growth more sustainable: evaluating the costs and benefits

Currently, traditional development issues such as economic stagnation, poverty, hunger, and illness as well as newer challenges like environmental degradation and globalisation demand attention. Sustainable development, including its economic, environmental and social elements, is a key goal of decisionmakers. Optimal economic growth has also been a crucial goal of both development theorists and practitioners. This paper examines the conditions under which optimal growth might be sustainable, by assessing the costs and benefits of growth. Key environmental and social aspects are considered. The Ecol-Opt-Growth-1 model analyses economic–ecological interactions, including resource depletion, pollution, irreversibility, other environmental effects, and uncertainty. It addresses some important issues, including savings, investment, technical progress, substitutability of productive factors, intergenerational efficiency, equity, and policies to make economic growth more sustainable—a basic element of the sustainomics framework. The empirical results support growing concerns that costs of growth may outweigh its benefits, resulting in unsustainability. Basically, in a wide range of circumstances, long term economic growth is unsustainable due to increasing environmental damage. Nevertheless, the model has many options that can be explored by policy makers, to make the development path more sustainable, as advocated by sustainomics. One example suggests that government supported abatement programs are needed to move towards sustainable development, since the model runs without abatement were infeasible. The optimal rate of abatement increases over time. Abatement of pollution is necessary to improve ecosystem viability and increase sustainability. Further research is necessary to seek conditions under which alternative economic growth paths are likely to become sustainable.

The politics of 'sustainability': a critical discourse analysis of Victorian Government policy discourse, 1999-2006

Since its emergence during the 1980s the idea of sustainability has come to provide the dominant frame within which environmental policy is debated. Thus, for many ‘sustainability’ represents the best way to address the economic, social and environmental effects of the myriad of environmental issues facing human societies, including biodiversity loss, soil erosion, pollution of waterways, ozone depletion and climate change. There are however, widely divergent views advocated as to what sustainability means, which has important implications for how serious environmental issues are understood to be, why they are important, what has caused them, and what needs to be done to address them. Given the diversity of such views, the consequences for policy making, and the likelihood of effective responses being developed, are self evident. Within this context, this thesis investigates the politics of sustainability, focussing particularly on the way in which it is defined, because of the implications this has for the way in which environmental issues are understood and addressed. Following a review of various approaches to analysing environmental policy (traditional, mainstream, ecopolitical and discursive), Norman Fairclough’s approach to discourse analysis (Critical Discourse Analysis) was identified as having particular merit. Fairclough’s approach avoids the assumption that policy issues exist independently of the way they are framed and offers a perspective on discourse that links the social theoretical concerns of Foucault with the micro level concerns of linguistics. It also provides a means for taking environmental policy analysis in directions that that have attracted relatively limited attraction, namely the detailed analysis of the ideological effects of language on environmental policy. In this thesis Fairclough’s approach is used to explore how three storylines of sustainability (sustainable development, environmentally sustainable growth and transforming society) and their associated discourses shaped environmental policy making in Victoria, Australia, between 1999 and 2006. In undertaking this analysis, I examined the political and institutional context informing policy making (social practice); the contested process of text production (discourse practice), and; the detailed wording of a policy text (textual analysis). A major policy statement on environmental sustainability released by the Victorian Government in 2005 is subjected to detailed analysis. Based on the analysis undertaken, the substantive finding from this research is that rather than moving beyond neoliberalism, the Victorian Government embraced an approach to sustainability that was informed by neoliberalism and (weak) ecological modernisation, which constructs sustainability in ways that limit its importance and constrain the types of responses that could be advocated. In doing so, it drew heavily on notions of natural assets and ecosystems services as ways to make sense of the environment and why it is important. The Victorian Government also highlighted that environmental issues are caused by the cumulative effects of individual choices, and emphasized the importance of individual choice and behavioural change as central features of sustainability, while restricting opportunities for more transformative ideas to be heard. The broader conclusion arising from this research is that approaches to environmental policy that rely on neoliberal and (weak) ecological modern discourses are flawed, because, in commodifying nature, limiting the nature and magnitude of change required, and placing responsibility onto individuals they offer a constrained understanding of the challenge of sustainability and what needs to be done about it. The overall contribution made by this research is an improved understanding of the discursive nature of the politics of sustainability and the influence of neoliberalism and ecological modernisation, the use of a methodology that has attracted relatively limited attention within environmental policy (despite its widespread use in other areas of policy) and the documentation of a period of significant environmental policy reform in Victoria.

Lifetime and fleece quality traits associated with the occurrence of entangled mohair staples

Staple entanglement in mohair fleeces occurs when adhesions form between longer and faster growing fibres and shorter and slower growing fibres. This results in accentuated crimp of the longer fibres and an "apparently" reduced staple length. The appearance in the fleece of Angora goats of staple entanglements can lead to the downgrading of the mohair to poorer style and shorter length grades, resulting in up to 60% price reductions. This study examined how staple entanglement score (SES) is related to lifetime factors of Angora goats, and how this relationship can be explained by variations in animal size and fleece attributes. SES was scored using a five-point scale: 5, long free fibres easily separated as no adhesions; 4, some adhesions between fibres; 3, some effort to separate fibres as many adhesions; 2, many adhesions, staple fibres entangled, shortening of staple; 1, very entangled and shortened staple. Measurements were made over 9 shearing periods on a population of Angora castrated males (wethers) goats representing the current range and diversity of genetic origins in Australia, including South African, Texan and interbred admixtures of these and Australian sources. Data on genetic origin, sire, dam, date of birth, dam age, birth weight, birth parity, weaning weight, live weight, fleece growth and fleece attributes were recorded. Two restricted maximum likelihood (REML) models were developed to relate SES with age, animal lifetime factors, fleece quality attributes and live weight. One model allowed fleece quality and live weight traits in the model and the other excluded these traits. Staple entanglement was almost eliminated in mohair harvested from goats shorn every 3. months but was common in mohair from goats shorn twice or once per year. SES was less in goats of Texan genetic background, and was generally less in winter grown mohair. SES was higher for mohair with low fibre curvature (FC, 10°/mm) and a high clean washing yield (CWY, 90%) compared with mohair with low FC and lower CWY (80%), and compared with all mohair with high FC (18°/mm). The response of SES to shearing regime, genetic background, shearing season, age of goat and a response to dam age were almost identical whether or not an adjustment was made for CWY and FC. There was a moderate amount of variability due to sires and individuals. We can conclude that a large part of these effects observed, namely breed, dam age, sire, and a component of the FC and CWY effects, are genetic. Mohair producers can manage the genetic effects by careful selection of sires, especially avoiding those with low CWY or high FC, and avoiding sires with higher levels of staple entanglement or that have produced progeny with higher levels of staple entanglement. Also, unidentified environmental effects are affecting staple entanglement, although a lack of a live weight change effect on entanglement indicates that this effect might not be due to nutrition. © 2013 Elsevier B.V.

The collaborative economy: a disruptive innovation or much ado about nothing?

An economy based on the exchange of capital, assets and services between individuals has grown significantly, spurred by proliferation of internet-based platforms that allow people to share underutilized resources and trade with reasonably low transaction costs. The movement toward this economy of “sharing” translates into market efficiencies that bear new products, reframe established services, have positive environmental effects, and may generate overall economic growth. This emerging paradigm, entitled the collaborative economy, is disruptive to the conventional company-driven economic paradigm as evidenced by the large number of peer-to-peer based services that have captured impressive market shares sectors ranging from transportation and hospitality to banking and risk capital. The panel explores economic, social, and technological implications of the collaborative economy, how digital technologies enable it, and how the massive sociotechnical systems embodied in these new peer platforms may evolve in response to the market and social forces that drive this emerging ecosystem.

Monitoring corrosion of reinforced concrete beams in a chloride containing environment under different loading levels

Corrosion has significant adverse effects on the durability of reinforced concrete (RC) structures, especially those exposed to a marine environment and subjected to mechanical stress, such as bridges, jetties, piers and wharfs. Previous studies have been carried out to investigate the corrosion behaviour of steel rebar in various concrete structures, however, few studies have focused on the corrosion monitoring of RC structures that are subjected to both mechanical stress and environmental effects. This paper presents an exploratory study on the development of corrosion monitoring and detection techniques for RC structures under the combined effects of external loadings and corrosive media. Four RC beams were tested in 3% NaCl solutions under different levels of point loads. Corrosion processes occurring on steel bars under different loads and under alternative wetting - drying cycle conditions were monitored. Electrochemical and microscopic methods were utilised to measure corrosion potentials of steel bars; to monitor galvanic currents flowing between different steel bars in each beam; and to observe corrosion patterns, respectively. The results indicated that steel corrosion in RC beams was affected by local stress. The point load caused the increase of galvanic currents, corrosion rates and corrosion areas. Pitting corrosion was found to be the main form of corrosion on the surface of the steel bars for most of the beams, probably due to the local concentration of chloride ions. In addition, visual observation of the samples confirmed that the localities of corrosion were related to the locations of steel bars in beams. It was also demonstrated that electrochemical devices are useful for the detection of RC beam corrosion.