Profit Maximization, Industry Structure, and Competition: A critique of neoclassical theory

Neoclassical economics has two theories of competition between profit-maximizing firms (Marshallian and Cournot-Nash) that start from different premises about the degree of strategic interaction between firms, yet reach the same result, that market price falls as the number of firms in an industry increases. The Marshallian argument is strictly false. We integrate the different premises, and establish that the optimal level of strategic interaction between competing firms is zero. Simulations support our analysis and reveal intriguing emergent behaviors.Comment: Accepted for Physica

Illustrating The Process Of Ontology Concept Formulation In A Multi-Perspective Social Setting

Developing an ontology for use in a social process requires conceptualisation of the domain, and the influence of skills and perspectives of actors in the processes to be considered. It is essential that methodologies have a rigorous concept formulation process that ensures abstraction from the domain narration and also disambiguates the terms in the narration. However, the abstraction needs to be a parsimonious representation of a community’s collaborative terminology and concept pluralism. This paper presents a method of ontological concept formulation, using an approach based on a rigorous grounded theory method, and illustrates the process using a fragment from a case study. We have found that the method has assisted in clarifying terms emerging from the text and in grounding the conceptual understanding of natural language fragments, by interpreting concepts at the phrase level with the support of a reference lexicon, and using a basis of perspectivism. The identification of semantic relationships between concepts is conducted within the multiple adopted perspectives and permits a pluralistic approach to ontological formulatio

Low Probability of Intercept Waveforms via Intersymbol Dither Performance under Multipath Conditions

This thesis examines the effects of multipath interference on Low Probability of Intercept (LPI) waveforms generated using intersymbol dither. LPI waveforms are designed to be difficult for non-cooperative receivers to detect and manipulate, and have many uses in secure communications applications. In prior research, such a waveform was designed using a dither algorithm to vary the time between the transmission of data symbols in a communication system. This work showed that such a method can be used to frustrate attempts to use non-cooperative receiver algorithms to recover the data. This thesis expands on prior work by examining the effects of multipath interference on cooperative and non-cooperative receiver performance to assess the above method’s effectiveness using a more realistic model of the physical transmission channel. Both two and four ray multipath interference channel models were randomly generated using typical multipath power profiles found in existing literature. Different combinations of maximum allowable symbol delay, pulse shapes and multipath channels were used to examine the bit error rate performance of 1) a Minimum Mean Squared Error (MMSE) cooperative equalizer structure with prior knowledge of the dither pattern and 2) a Constant Modulus Algorithm (CMA) non-cooperative equalizer. Cooperative MMSE equalization resulted in approximately 6-8 dB BER performance improvement in Eb/No over non-cooperative equalization, and for a full range symbol timing dither non-cooperative equalization yields a theoretical BER limit of Pb=10−1. For 50 randomly generated multipath channels, six of the four ray channels and 15 of the two ray channels exhibited extremely poor equalization results, indicating a level of algorithm sensitivity to multipath conditions

Malaria antigens involved in protective immunity

The rodent malaria Plasmodium yoelii is used as a laboratory model for human malaria. The invasion of erythrocytes by Plasmodium merozoites is thought to be mediated by rhoptries; the mechanism of invasion is unknown. A monoclonal antibody recognising a 235kD P.yoelii rhoptry antigen was isolated by Freeman et al. The monoclonal antibody, which was protective on passive transfer appeared to alter the specificity of the parasite causing preferential invasion of reticulocytes followed by clearance of infection. The first section of the thesis describes the isolation of a P.yoelii DNA fragment thought to code for a blood stage merozoite rhoptry antigen. Antisera raised against a fusion protein and a synthetic peptide appear to recognise rhoptries by indirect immunofluorescence. Antibodies selected from P.yoelii immune serum immunoprecipitate a blood stage protein of 235kD and recognise a similar sized protein on Western blots. Sequence data, Southern blots and PCR amplification suggest that cloned DNA fragments may be present as more than one copy in the P.yoelii genome. Cross species hybridisation shows the gene sequence to be present in other rodent Plasmodia. The second section of the thesis covers experiments attempting to identify the components of isoelectrically focussed P.yoelii fractions. De Souza and Playfair have shown that certain fractions can protect mice against challenge infection as effectively as a total parasite lysate. Antibodies to focussed fractions were used to immunoprecipitate labelled P.yoelii proteins and in immunofluorescence studies. Antibody depletion experiments were carried out on focussed fractions to try to identify protective components

Human PrimPol mutation associated with high myopia has a DNA replication defect

PrimPol is a primase-polymerase found in humans, and other eukaryotes, involved in bypassing lesions encountered during DNA replication. PrimPol employs both translesion synthesis and repriming mechanisms to facilitate lesion bypass by the replisome. PrimPol has been reported to be a potential susceptibility gene associated with the development of myopia. Mutation of tyrosine 89 to aspartic acid (PrimPolY89D) has been identified in a number of cases of high myopia, implicating it in the aetiology of this disorder. Here, we examined whether this mutation resulted in any changes in the molecular and cellular activities associated with human PrimPol. We show that PrimPolY89D has a striking decrease in primase and polymerase activities. The hydrophobic ring of tyrosine is important for retaining wild-type extension activity. We also demonstrate that the decreased activity of PrimPolY89D is associated with reduced affinities for DNA and nucleotides, resulting in diminished catalytic efficiency. Although the structure and stability of PrimPolY89D is altered, its fidelity remains unchanged. This mutation also reduces cell viability after DNA damage and significantly slows replication fork rates in vivo. Together, these findings establish that the major DNA replication defect associated with this PrimPol mutant is likely to contribute to the onset of high myopia

Understanding the Benefits of Ontology Use for Australian Industry: A Conceptual Study

In IT, rather than philosophy, an ontology makes explicit the meanings of terms used in domains, or concerning a specific reality, so that people and machines can precisely discuss the meaning of data. Specifically, ontology makes data sharing and analysis easier by making the meaning of data, and of the reality to which the database refers, explicit. Ontology has significant uptake in biomedicine but not yet in industry despite much technical development and reporting of specific successes. This research seeks to determine how and why organisations gain benefits from using ontology leading to a rigorously tested model of how business gains benefit from ontology use. This research in progress paper develops a model explaining the benefit of ontology use to firms and outlines our plans to test the model empirically. The outcome is significant for Australian industry because it will guide the efforts of organisations to use ontology effectively