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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
481

The role of production subsidies in general equilibrium macroeconomic models with imperfect competition

Kwan, Chang Yee January 2010 (has links)
Industrial policy in the form of direct and indirect government subsidy provision to firms in specific sectors of the economy is a common sight in many countries. Some of the most often quoted examples are East Asian economies such as japan and Taiwan. While industrial policy is touted as a possible engine to generate economic growth, empirical validations on the benefits from subsidy provisions have been mixed. It is often argued that a policy of non-intervention by the government may appear to be the optimal policy to pursue. However, this contrasts with the historical observations of regular government subsidy provisions to firms in many countries. This thesis constructs a two-sector non-monetary macroeconomic model with monopolistic competition to examine welfare and other related effects of a subsidy provision in the form of lump sum transfers or as some proportion of a variable cost component while firms in the perfectly competitive sector do not. This analysis is first carried out in an economy where labour supply is assumed to be exogenous and perfectly inelastic. This serves to provide a simple and clear exposition on the effects of a subsidy provision and to serve as a benchmark analysis to build upon. This is subsequently extended by allowing for labour supply to be endogenously determined to examine labour market effects of subsidy policies. The implications of subsidy provisions in the presence of international trade are studied by constructing a small open economy model where the effects of any policy implementation do not affect world prices or income. The principle findings we obtain are that when monopolistically competitive firms receive a cost-reducing subsidy, welfare improvements are always possible regardless of which cost variable the government subsidises. Furthermore, there is always a positive optimal subsidy which raises social welfare. When the supply of labour is endogenous, the corresponding tax imposed on income will always induce an increase in labour supply. Trade is shown not to affect the principle findings: there remains an optimal level of subsidy which is Pareto-improving. A further implication in the open economy context is that the subsidy acts as a form of import-substitution and export-promotion instrument which potentially alters the domestic economy's trade patterns.
482

A comparison of between-tree competition effects in separate stands of a Eucalyptus grandis seedling and a single Eucalyptus grandis x urophylla hybrid clone

Sale, Giovanni 15 November 2006 (has links)
Student Number : 0115350V - MSc dissertation - School of Plant, Animal and Environmental Science - Faculty of Science / The effect of between-tree competition in separate even aged stands of a Eucalyptus grandis seedling and a single Eucalyptus grandis x Eucalyptus urophylla hybrid clone was assessed. This was done by comparing treatments within an experiment, that was designed to test the effect planting density and genotype had on timber production and stand dynamics through time. This experiment is located on an escarpment in the Summer rainfall region of South Africa, approximately 7 km North West of Albert Falls dam in the Kwa-Zulu Natal Midlands. The terrain is flat with deep apedal soils, and the site has an estimated mean annual precipitation of 1143 mm. The simplest method of evaluating competition effects in plantation stands is through the use of spacing trials. Spacing trials create stands/plots in which all silvicultural and climatic variables are constant. Differences between treatments can then be attributed to competition alone. The planting densities tested were 6667 stems.ha-1, 3333 stems.ha-1, 2222 stems.ha-1, 1587 stems.ha-1 and 1111 stems.ha-1 respectively. Competition was measured at three levels, namely; (i)individual tree, (ii)size-class and (iii)stand level. Vigour and its distribution within the population were used to explain competition processes. Basal area was chosen as the size variable for which vigour would be analysed. Relative Growth Rate (RGR) and Relative Production Rate (RPR) were chosen as the measures of vigour for analysis. Morphological changes in the trees as a result of competition were also used to understand the competitive mechanisms. It was found that resources are not shared amongst individuals in proportion to their size, but rather the larger individuals use disproportionately more of the resources than the smaller individuals, and therefore competition is asymmetrical. The dominant form of competition was found to be resource pre-emption where larger individuals passively prevent solar resources from reaching smaller competitors. Using RPR as the measure of vigour, competition was found to be one-sided, meaning that smaller individuals do not reduce the vigour of larger ones. If RGR is accepted as the measure of vigour then competition is two-sided meaning that the smaller individuals do reduce the vigour of the larger ones to a certain extent. There was no difference in the degree to which the smaller competitors in the clonal and seedling treatments reduced the growth of the larger individuals. The self-thinning rate in the seedling treatments was significantly higher than in the clonal treatments. Increases in mean tree size and production per hectare were accompanied by increases in mortality in the seedling treatments. In the clonal treatments it was found that even once the mean tree size approached the self thinning line, very few or no trees died, however there was also very little or no increase in mean tree size. When the relationship between number of live trees and production per hectare was analysed it was found that the clone could increase production per hectare without any change in survivorship, which is contrary to popular theory. As time progressed the skewness of the population progressed from negative to positive. This increase was the most pronounced in the higher planting density treatments, and the clonal treatments. The size variability in the population first decreased, then steadily increased. This increase was more pronounced in the high planting density treatments, and the clonal treatments. Clones and seedlings react in very different ways to competition. The large differences in population dynamics observed, indicate that we cannot just apply knowledge built up over the years regarding the management of Eucalyptus grandis and other plantation species to Eucalyptus hybrid clones.
483

Natural and Sexual Selection Shape the Acoustic Phenotype of Urban Birds

January 2017 (has links)
acase@tulane.edu / Anthropogenic noise is an evolutionarily recent phenomenon and many animals respond by changing the pitch and timing of their vocalizations to avoid masking. A benefit to modifying a vocal mating signal in the context of noise is increased transmission distance. This same modification may pose a fitness cost if that signal feature is also sexually selected. Bird song is a well-studied sexual signal used in territory defense and mate attraction. Physically difficult to produce components of song are thought to be honest signals of male quality. One such trait is a male's ability to maximize the rate of note production at a given frequency bandwidth; this tradeoff is known as vocal performance. Studies have shown modifications to song in the context of noise, specifically to trill rate and bandwidth. Costs of these modifications may include increased conflict with neighboring males, which could potentially lead to decreased body condition, loss of a territory, or less time spent attracting a female. Few studies have investigated this tradeoff between environmentally induced selection (i.e. natural selection) and social selection (i.e. sexual selection) on song in an urban landscape. Therefore, a gap remains in our knowledge of the consequences on fitness of urban song adaptation for signalers. Using the white-crowned sparrow (Zonotrichia leucophrys) in the San Francisco Bay Area of California, the objectives of my dissertation research include 1) testing if vocal performance is a salient signal for white-crowned sparrows, 2) testing if receivers are responding specifically to variation in trill rate or bandwidth, and 3) testing the effect of ambient noise level on receiver assessment of vocal performance. Overall, my dissertation research suggests that both anthropogenic and natural soundscapes shape the evolution of song and receiver behavior. Modifications to song structure that increase signal detection come at the cost of decreased signal salience for male competitors. Additionally, anthropogenic noise appears to change how males utilize vocal performance. Therefore, species living in noisy areas may face consequences of decreased fitness over time due to masked honest signals and increased male-male conflict. / 1 / Jennifer N. Phillips
484

Real-Time Competition Processes in Word Learning

Apfelbaum, Keith S. 01 July 2013 (has links)
Perceptual processes take time to unfold. Whether a person is processing a visual scene, identifying the category an object belongs to, or recognizing a word, cognitive processes involving competition across time occur. These ongoing competitive processes have been ignored in studies of learning. However, some forms of learning suggest that learning could occur while competition is ongoing, resulting in the formation of mappings involving the competing representations. This dissertation uses word learning as a test case to determine whether such learning exists. In a series of five experiments, participants were taught words under different stimulus and task conditions to encourage or discourage learning during periods of lexical competition. These studies reveal a complex relationship between ongoing lexical competition processes and word learning. Specifically, in cases where learners rely on unsupervised associative learning, they present evidence of learning that is continuous in time, starting during periods of lexical competition and continuing throughout the course of its resolution. These studies offer insight into the nature of associative learning, into the forms of learning that occur when learning new words, and into the ways that task and stimulus structure impinge on how a learner forms new associations.
485

Plant Spacing: A Size Sensitive Model With Implications for Competition

Bayn, Robert L, Jr. 01 May 1982 (has links)
An algorithm is presented which partitions space among mapped plants according to their relative sizes and positions using one of eight rules for locating boundaries between individuals. The performance of those rules is examined using several natural and artificial data sets with diverse measures of individual size. The relative performance of the rules was the same for all natural data sets examined. The best rule, as measured by a high correlation between individual size and assigned space, placed the boundary at a distance between neighbors proportional to the relative sizes of neighbors as long as a maximum distance (also a function of size) was not exceeded. It is inferred that the algorithm identifies contact neighbors and quantifies the extent of their contact. Afield experiment is proposed to test this inference.
486

Cue Competition During Phonotactic Processing in Bilingual Adults as Measured by Eye-Tracking

Manrique, Katherine 26 June 2018 (has links)
It is well documented in the literature that bilingual speakers simultaneously activate both languages during spoken language processing (e.g., Marian & Spivey, 2003). However, parallel activation can lead to competition between the two languages (e.g., Blumenfield & Marian, 2013; Freeman, Shook, & Marian, 2016). The Unified Competition model (UCM) provides a theory as to how bilingual speakers navigate through two languages while different linguistic cues are competing (MacWhinney, 2005). The UCM proposes that cues are used to process language, based on cue validity (the product of how reliable and available a cue is), which is determined by cue strength (a measure based on conflict reliability; how reliable a cue is when it directly conflicts with others). Two likely cues bilingual speakers use while processing a novel spoken word are linguistic environment (the language being spoken around them) and phonotactic probability (the probability of the sounds making up a novel word). Applying the theory of the UCM this study sets to answer the following general question: How do Spanish/English bilingual adults assign language membership to nonwords when linguistic environment and phonotactic cues are competing? The current study consisted of twenty-two Spanish/English adults who listened to 96 nonwords that corresponded to three different groups based on phonotactic probability: Language Exclusive (the phonotactics of the nonwords designated them as either Spanish only or English only), High-Low (the nonwords had high phonotactic probability in one language and low probability in the other), and Ambiguous (the nonowords had similar phonotactic probability in both languages). The participants were tested in one of two linguistic environments (primarily English with some Spanish code-switching or primarily Spanish with some English code-switching) and partook in a two-alternative forced choice listening test (participants determined if each nonword was either Spanish or English). The language membership decision was measured via verbal response and eye-tracking using EyeLink 1000 Plus measuring eye gaze, number of fixations and switches. In general, results indicated that Spanish/English bilingual adults relied only on phonotactic probability when making language membership decisions, but not as strongly as may be suggested by the UCM. The results of this study suggest that environmental cues are not strong enough to impact spoken language processing in Spanish/English bilingual adults and that phonotactic probability is likely a more easily accessible (and therefore more commonly used) cue.
487

Gender differences in the dynamics of group competition

Roy, Rosanne. January 1999 (has links)
No description available.
488

Privatisation and market structure : a game theoretic approach

Livaic, Zelko F., University of Western Sydney, Nepean, Faculty of Business January 2000 (has links)
This thesis focuses on the impacts of privatisation on the relevant industrial structure of the economy. Standard tools of industrial organisation theory are applied to examine these impacts and, thereby, shed light on relevant welfare issues. The focus of this thesis is to examine the ramifications of privatisation in imperfectly competitive markets. Simple Cournot-Nash types of games have been developed, where the market is a duopoly containing a privatised firm with the other firm being a new entrant. These games examine the efficacy and impacts of privatisation, and the role of government in this duopoly. The thesis endrogenously derives multiple equilibria in the duopolistic market; examines decontrolling/deregulating a vertical market; looks at the potential competition in vertical markets and examines potential collusion among existing firms to forestall entry; and addresses issues of privatisation in successive duopolies with cooperative investments. Results show that whether privatisation is beneficial to the community will rely on the astute role of government intervention. / Doctor of Philosophy (PhD)
489

THE ECOLOGY OF FERAL CATS, FELIS CATUS, IN OPEN FOREST IN NEW SOUTH WALES: INTERACTIONS WITH FOOD RESOURCES AND FOXES

MOLSHER, Robyn Lorraine January 1999 (has links)
ABSTRACT Despite increasing evidence for the impact of feral cats Felis catus on native fauna in Australia, little is known of the ecology of cats, particularly factors that limit cat abundance. The ecology of the feral cat in Australia is represented by just 15 published studies on diet, only one of which has examined diet in relation to prey availability, and one study of home range behaviour. The red fox Vulpes vulpes is a significant pest to agriculture and native fauna in Australia and widespread fox removals have been proposed by the Vertebrate Biocontrol Cooperative Research Centre (VBCRC). However, there is concern that feral cats may increase compensatorily when fox populations are reduced, as has occurred in Western Australia, and therefore that predation pressure may not be alleviated on native fauna following fox control programs. This thesis is divided into two parts. First, the diet and home range size of cats is examined in relation to prey availability, and home range overlap and habitat use are determined. In the second part, several niche parameters (diet, home range and habitat use) that were potentially important resources for foxes and cats were quantified to assess the potential for competition. Avoidance and aggression between cats and foxes was examined using simultaneous radiotracking techniques and video observations. The hypothesis that foxes limit cats through interspecific competition (exploitation and interference) was then tested using a fox removal experiment. Finally, three further hypotheses were tested using a fox removal experiment to determine which factors limit feral cats at Burrendong. The four hypotheses tested were thus: i) Cats are limited independently of foxes through other factors such as food availability; ii) Foxes limit cats through interspecific competition (exploitation and/or interference); iii) Foxes limit cats through intraguild predation; iv) Cats benefit from the presence of foxes through facilitation. The diets and spatial use of feral cats were examined on agricultural land on the eastern shore of Lake Burrendong, New South Wales (32o40�S, 149o 10�E) between July 1994 and June 1997. The major land use for the area is water catchment under the agistment of sheep Ovis aries and cattle Bos taurus. The study area encompasses about 90 km2 of hilly terrain with undulating slopes that extend down to a flat foreshore area that has been extensively cleared of trees for grazing. The slopes are generally well timbered and dominated by white box Eucalyptus albens woodlands with some yellow box E. melliodora associations. Stands of cyprus pines Callitris spp. are also common. Feral cats and red foxes are established throughout the study area, and the European rabbit Oryctolagus cuniculus was abundant until the arrival of Rabbit Calicivirus Disease (RCD) in June 1996. The diet of feral cats was determined from the analysis of 499 scats. Rabbits were the staple prey of cats, with occurrence (O) in 81.6% of scats and comprising 68.4% by volume (V). Carrion (mostly eastern grey kangaroo Macropus giganteus and sheep) (O 21.5%, V 11.5%) was an important secondary food, particularly in winter and spring. Other mammalian prey included brushtail possums Trichosurus vulpecula (O 4.6%, V 2.4%), house mice Mus domesticus (O 6.2%, V 3.2%), black rats Rattus rattus (O 2.6%, V 1.4%) and a dunnart Sminthopsis sp. (probably S. murina) (O 0.2%, V 0.006%). Invertebrates (mostly Orthopterans) (O 41.5%, V 7.5%), vegetation (O 26.3%, V 3.6%), birds (O 4.2%, V 0.8%) and reptiles (O 3.4%, V 0.3%) were generally of minor importance in the diet. Few significant seasonal differences were found, although invertebrates contributed significantly less, and possums more, to the mean scat volume in winter and summer respectively. A significant dietary response was found for changes in rabbit abundance, but not for the other prey groups. Cats continued to prey heavily on rabbits after the arrival of Rabbit Calicivirus Disease, despite the relatively low numbers of rabbits. Ten months post-RCD, house mice increased in importance in the diet. However, it was not known whether this represented prey switching sensu stricto or opportunistic predation on an increased mouse population, as mouse abundance was not measured during this period. Seventy-seven cats (48 recaptures) were caught in 6762 trap nights between November 1994 and August 1996 using both cage traps and leg-hold traps. A further 18 individual cats were trapped as non-target animals by the VBCRC Fox Sterility Project and used in this study. Trapped adult cats were fitted with radio collars and their home range size, overlap and habitat use examined. Home ranges and core areas were quantified using 95% and 50% kernel utilisation distributions (KE 95 and KE 50) and minimum convex polygons (MCP 100, MCP 95, MCP 50). Four habitat types (grassland, open woodland, open forest, and mudflats) were delineated on aerial photographs and a habitat map produced using ARC/INFO. Compositional analysis was used to examine habitat preference in cats. Home range sizes of cats (n = 15, 598 fixes) in winter 1995, prior to fox removal, were similar to those reported in the only published study of cat spatial use in Australia, but larger than those recorded elsewhere. This may have reflected more dispersed food resources in Australia, although home range size was not correlated significantly with rabbit abundance. Male ranges (MCP 95 = 284 ha, n = 11) tended to be larger than females ( = 151ha, n = 4), but no differences were detected between young (1-3 years, = 271ha, n = 7) and old (>3 years, = 221ha, n = 8) cats. Cats were active both by day and night with no temporal differences being detected in range size. Both adult male and female cats tended to be solitary, although home ranges overlapped extensively. Kin groups were indicated (but not confirmed) as most inter-sexual overlap occurred between young and old cats. Habitat composition of home ranges generally reflected the availability of habitats at the study site, although cats significantly avoided mudflats. Home ranges comprised mostly open woodland and open forest habitats with smaller areas of grassland and mudflats. However, within individual home ranges, cats used grassland and open woodland habitats most often where rabbits were more abundant. Inter-individual (sex, age) or temporal (day/night) differences in habitat use were not detected. Comparison of resource use between cats and foxes indicated a large overlap in diet, home ranges and habitat use. Dietary breadths and overlaps between cats and foxes increased when rabbit availability declined in autumn and post-RCD. Dietary overlap was high overall (75%), although some resource partitioning was detected. Rabbits were more important in the diet of cats than foxes, particularly in summer, when foxes ate more grasshoppers. Carrion, invertebrates and vegetation were more important for foxes than for cats overall. Home ranges of both cats and foxes comprised mostly open woodland habitats followed by grassland, open forest and mudflats, which largely reflected their relative availabilities. However, within individual home ranges, cats showed a preference for grassland habitats. In addition, cats tended to deposit scats more often than foxes at rabbit warrens and at hollow log entrances, while foxes deposited scats more often than cats on sand plots, tracks and at dams. The large overlap in resource use between cats and foxes indicated a high potential for exploitation competition. Foxes may attempt to lessen competition by killing cats (interference competition). Three radiocollared cats were killed by foxes and aggression was observed toward cats. Home ranges overlapped extensively, but avoidance was indicated from the simultaneous radiotracking of both predators, as greater separations and lower overlaps in home ranges and core areas were recorded between species than within species. In addition, video observations suggested avoidance of carcasses by cats in the presence of foxes. The hypothesis that foxes limit feral cats through interspecific competition was then tested using a fox removal experiment. Foxes were reduced at two of the four sites from October 1995 using �1080� baiting and spotlight shooting by the VBCRC Predator-Prey project. Resource use and abundance of cats were compared before and after fox removal and between treated and untreated sites. Although no increase in cat abundance followed the removal of foxes, significant behavioural changes by cats strongly suggested interspecific competition operating via exploitation and interference. Exploitation competition was supported by the increased consumption of carrion by cats at the treated sites after fox removal, while support for interference competition came from the increased use of grassland habitats at night after fox removal. The direction of the resource shifts to more prey-rich habitats indicated asymmetry in the relationship between the two predator species. Although the null hypothesis of no limitation of cats by foxes could not be rejected, as no increase in cat abundance was recorded after fox removal, interspecific competition was considered to be the most likely mechanism limiting feral cats at Burrendong. Intraguild predation was not indicated as no cat remains were found in any of the 343 fox scats or 255 fox stomachs that were examined. In addition, minimal evidence was found for facilitation between cats and foxes, or for food limitation. The potential for foxes to limit cats, as shown in this study, indicates that cats need to be considered in future fox control operations. Integrated pest management, where foxes, cats and rabbits are controlled together, is strongly proposed if the objective is to safeguard native fauna in Australia. Further research is required to improve the effectiveness of current techniques for censusing cat populations, particularly in forested areas. This is essential for monitoring the effectiveness of control campaigns and quantifying factors that limit cat populations, and ultimately for effective protection of susceptible native fauna.
490

The Quest of Australian Public Universities for Competitive Advantage in a Global Higher Education Environment

Bradmore, Donald James, don.bradmore@rmit.edu.au January 2007 (has links)
Adopting a triangulated approach, this thesis consists of three separate but related qualitative studies, the collective objectives of which are to (i) gauge current levels of concern of Australian public universities with rapid intensification of the higher education sector globally; (ii) evaluate strategies developed by universities in response to increasing competition; and (iii) develop a conceptual framework to guide competitive behaviour of universities. Study 1 is a systematic content analysis of published strategic plans of universities using Leximancer (Version 2.20). Relative prominence of concepts identified in this content analysis give rise to propositions relating both to levels of concern with competition and strategies being implemented to protect market position. In Study 2, these propositions are tested in a sample of the universities by means of case studies based on face-to-face interviews with senior academics and administrators. Study 3 draws upon findings of Studies 1 and 2 to develop a strategic model to guide future strategy development. Overall, findings of the studies provide valuable insights into the management of higher education in a dynamic environment in which the intensity of competition is likely to escalate as the pace of globalisation and technological change quickens, as deregulation of the domestic higher education sector continues, as per capita funding is further reduced, as even greater elements of competition and contestability are introduced in the interests of productivity and efficiency, and as overseas student demand slackens in traditional markets.

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