36 resultados para seed viability

em Deakin Research Online - Australia


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This project aimed to quantify the potential for wild birds to spread genetically modified seeds from their area of planting to adjacent areas, through ingestion and transport in the gut (endozoochorous transmission). We addressed this by assessing whether seed viability was affected by passage through the avian gut. We sought to address this question by testing the effects of ingestion of a number of key agricultural crops by three common wild bird pest species.

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1. The potential for seed dispersal by fish (ichthyochory) is likely to vary within aquatic plant species, depending on intraspecific variation in phenotypic seed traits.

2. We studied the effect of seed size variation within the unbranched burreed (Sparganium emersum) on the potential for internal dispersal by the common carp (Cyprinus carpio), by feeding them light (< 10 mg), medium (10–20 mg) and heavy ( > 20 mg) seeds, seed mass being positively related to seed size.

3. We hypothesized: (i) that ingestion, retention time, survival during gut passage and viability after gut passage of S. emersum seeds would be affected by seed size; and (ii) that this would translate into intraspecific variation in dispersal probability and dispersal distance among seed size categories.

4. Ingestion was negatively related to seed size, while survival during gut passage was positively related to seed size. Seed viability after gut passage was not affected by seed size. Since the negative effect of ingestion was counterbalanced by an equally strong but positive effect on seed survival, the probability of dispersal did not differ between the tested seed-size categories.

5. The time that seeds remained in the digestive tract of carp did not differ between seed sizes, suggesting equal potential dispersal distances for all seeds. Based on optimum swimming speeds of carp, ranging from 0·9 to 1·8 km h−1, maximum dispersal distances will most likely range from 13·5 to 27 km.

6. This study highlights the importance of studying all stages of the endozoochorous dispersal process in order to estimate the effect of a phenotypic seed trait on plant dispersal.

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Marketing strategy in performing arts organisations has become particularly important in the increasingly competitive environment in which the arts operate. Since the late 1980s there has been a necessary shift in focus to audience development away from product development. This change in focus is being encouraged to ensure the long-term viability of performing arts organisations (PAOs) and micro-economic reform. While government reports have recommended strategies aimed at building audience based recognition, this is an expensive approach for many PAOs and does not produce short term returns. Little attention has been paid to building enduring relationships with existing audiences as a way if having a more dramatic impact on PAOs' long-term viability. This paper explores this theme through relationship marketing and the implication of retaining existing audiences. The paper identifies the changing cultural environment which has led to the importance if marketing. It then explains the concepts if relationship marketing and its pertinence to PAOs' viability by presenting a loyalty ladder. The structure is modelled as a dynamic conceptualisation of the relationships (audience and organisation) to assist arts managers to decide whether to focus their efforts on catching or keeping customers to maximise earned income.

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Single crystal seeds of the nickel-base superalloy CMSX-4 have been partially melted in a temperature gradient and then quenched. Small islands of random orientation are observed throughout the melted-back semi-solid. These random orientations appear to be pinched-off secondary dendrite arms, but there is no evidence that they are transported ahead of the dendrite tips to nucleate stray grains during directional solidification.

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An essential component of marketing strategy is pricing. Pricing in museums, however, is problematic as issues beyond cost recovery or surplus, such as social responsibilities, need to be considered. This area of marketing is under researched. The aim of this study is to address the research gap by synthesising the literature on pricing strategy in the museum sector. The study found that there are a number of strategies being advocated with regard to pricing in the museum sector in the literature, each representing various perspectives of museology. A research agenda was proposed to assist marketers in the museum sector to meet their organisational needs, whilst balancing their social responsibilities.

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Inland fisheries contribute only about ten percent to global fish production. Asia is the leading producer of inland fish, accounting for over 80 percent of the total production. Until recently, the inland fisheries sector had taken back stage in fisheries development plans, particularly so, given the emphasis being placed on aquaculture development throughout the world, including Asia. This report evaluates the inland fishery practices in a number of Asian countries according to habitat type, role in overall foodfish supplies and development trends. Special emphasis is laid on stock enhancement in inland fisheries in Asia, and only those fisheries in which some form of stock enhancement is practised are considered in this report.

In Asia, inland fisheries are mostly rural, artisanal activities catering to rural populations and providing an affordable source of animal protein, employment and household income. Stock enhancement is an integral component of many inland fisheries. With recent developments in
artificial propagation techniques for fast-growing and desirable fish species and the consequent increased availability of seed stock, such activities are beginning to affect inland fishery production in most Asian countries. Indeed, new avenues of production such as culture-based fisheries are increasingly adopted and seen as a way forward in most countries. Inland fishery activities also have a distinct advantage in that their development is usually less resource intensive than is aquaculture.

The economic viability of stock enhancement of large lacustrine waterbodies and rivers has not been demonstrated in any of the Asian countries, the fisheries of such waterbodies being dependent on naturally recruited stocks. The most successful stock enhancements in Asia are in floodplain beels and oxbow lakes in Bangladesh where the use of small waterbodies that are not capable of supporting natural fisheries has led to culture-based fisheries having stock and recapture rates that are very high. Culture-based fisheries are not resource intensive and are community-based activities. However, their success requires major institutional changes, and these are affected by national and local governments. In general, they can be considered to have the greatest potential for further development.

A major concern related to stock enhancements in inland waters is their possible effects on biodiversity. This is for two reasons: firstly, most countries depend wholly or partially on exotic species for stock enhancement and secondly, freshwater fishes are known to be among the most threatened of vertebrates. Major studies should be undertaken to evaluate the current situation so that remedial steps can be taken, if needed, without causing serious harm to some of the stock enhancement practices that are gaining momentum.

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With the advent of widely-accepted eBusiness activities, many banks have floated dot.com entities to create a presence on the Internet and take advantage of its power and reach. Like many other businesses, banks expected an increase in market capitalisation as a result of their dot.com floats, perceived broadly as a measure of growing profitability. Despite the negative publicity that the recent spate of dot.com crashes has generated, banks seem to continue floating online spin-offs. Our exploratory study investigates this phenomenon, studying the drivers for change in the evolution of the banking sector, and the move towards electronic banking. We focussed on two economies – Australia and India – to aggregate the major factors in this evolution from the perspective of two disparate economies.

The paper describes our qualitative, document-based investigation of the Australian and Indian banking sectors, and subsequent quantitative analysis of the impact of dot.com floats on market capitalisation within this market sector. We then describe the effect of applying both Transaction Cost Economics to our findings, which indicates that the cost of transacting business has been reduced overall by the creation of dot.com entities; and “catch-up, fall-behind, forge ahead” theory to gain an economic perspective. The paper provides both practical assistance for banks in making decisions regarding e-portfolios, as well as for policy makers in the economies reviewed; and has the potential to contribute to academic research into eBanking more generally.

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Drifting, fertile thalli are well documented to be the primary long-distance dispersal vector for many marine macroalgae, but little information about reproductive viability of drift is known. This study examined the reproductive viability and longevity of floating fragments of the intertidal Australasian fucoid Hormosira banksii (Turner) Decne. Beach wrack surveys and field experiments were conducted to test the model that long-distance dispersal is achieved in H. banksii via floating, fertile fronds. High densities of beach wrack fragments were evident during summer compared to autumn. The majority of beach wrack occurred on sandy beaches rather than rocky shores. Both male and female fragments were present in the beach wrack. Detached fronds were capable of releasing gametes up to 8 weeks after detachment. Beach wrack produced high fertilization rates and recruited successfully onto artificial panels. Results suggest that detached fragments are reproductively viable and that floating, fertile fronds may be an important mechanism for facilitating long-distance dispersal in this species. Nevertheless, the frequency of fronds reaching a suitable habitat and contributing to gene flow between populations, or colonizing new populations, may not be proportional to the total density of beach wrack.

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The article presents a study which evaluates the impact of saltmarsh perturbation on seed quality of Sarcocornia which is a food for the endangered Orange-bellied parrot in Australia. It notes the significant impact of grazing on the energy and availability of Sarcocornia seeds in saltmarshes and indicates that graze-free saltmarshes with regular inundation provide the highest potential for Sarcocornia seed availability. Further, the substantial factor of soil characteristics and salinity of flood water and inundation on the seed production of Sarcocornia is also discussed.