1,382 research outputs found

    Navigation by satellite using two-way range and doppler data

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    Navigation by satellite using two-way range and Doppler dat

    Investment in property by Australian superannuation schemes

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    The superannuation sector in Australia accounts for close to AUD 2.5 trillion, representing major institutional investors in both a local and global context, of assets under management (AUM) in Australia's managed fund industry. This level of AUM makes up the majority of AUM in the industry. Over the past few decades, superannuation schemes have come to regard property as a key asset class to include in their multi-asset portfolios. This thesis explores the decision-making made by superannuation schemes when investing in property. lt does this by identifying the main criteria used in this decision-making through a survey process and rigorous analysis. To establish a background for the research in the thesis, an overview of the superannuation industry and descriptive case studies are undertaken to provide an understanding of the property exposure and allocation strategies of Australian superannuation schemes and overseas pension funds. The level of investment in direct property and indirect property, that is unlisted property funds and separate accounts, and listed property, is analysed. This background and the literature review on previous decision-making surveys allow seven independent factors and twentytwo independent sub-factors to be identified as the main criteria influencing the property investment decision-making process by institutional investors. The questionnaire models used in previous surveys did not allow respondents to indicate their level of preference for each of the factors and sub-factors. Consequently, a multi-criteria decision-making model was adopted to construct questions where respondents used pair-wise comparisons to indicate the importance of each factor or sub-factor relative to another factor or sub-factor. This allowed degrees of importance for each factor or sub-factor to be established. Two sample groups, superannuation schemes and wholesale property funds, are surveyed by way of face-to-face interviews. A broad range of non-profit superannuation schemes of different sizes were surveyed, with the respondents being a chief investment officer or investment manager. As property is such an expensive asset to invest in, superannuation schemes often invest in wholesale property funds to obtain property exposure. Consequently, managers of wholesale property funds that invest on behalf of superannuation schemes in direct property were also surveyed. While time and travel restrictions limited the number of superannuation schemes and wholesale property funds that could be surveyed, the AHP methodology allows reliable and consistent findings to be generated from the survey responses. Strategic decision-making is found to be the main factor influencing property investment by the superannuation schemes and wholesale property funds. The degree of importance placed on strategic decision-making by the survey respondents is considerably higher than the degree of importance they place on the other factors. This is in contrast to previous surveys undertaken over the past fifty years, which identified property type and location as the main factors influencing decisionmaking. Core, risk-adjusted return and return are found to be the main sub-factors. Previous surveys had ranked return analysis above risk-adjusted analysis. The responses by sub-groups of the superannuation schemes and the wholesale property funds were also analysed. Four significant differences were found to exist between the responses made by the superannuation scheme sub-groups, which are small, medium and large superannuation schemes. The differences are for two factors, property type and investment style, and two sub-factors, return analysis and local experience. Restrictive mandates and the lower level of funds held by the smaller superannuation schemes relative to the larger superannuation schemes could be reasons for these differences. Only one significant difference existed between the sub-group responses made by the diversified, retail, office and industrial wholesale property funds. lt was for the sub-factor unlisted property fund. This thesis contributes in three ways to the limited knowledge currently available on property investment decision-making by institutional investors. Firstly, it provides an in-depth analysis of the current strategic property allocation by superannuation schemes. Secondly, it identifies the main decision-making factors and sub-factors. Lastly, differences in the decision-making by the sub-groups of superannuation schemes and wholesale property funds are found to exist. Future research should be undertaken on the main factors and sub-factors identified in this thesis, to find out why they are so important. The reasons for the differences between the sub-groups decision-making should also be researched to establish if they affect the returns on their investment in property

    Assessment of Unsteady Propagation Characteristics and Corrections in Aeroacoustic Wind Tunnels Using an Acoustic Pulse

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    Two types of aeroacoustic wind tunnel test section configurations have been tested in the NASA Langley Quiet Flow Facility. The first is a more traditional open-jet configuration, where test section flow passes unbounded through the facility anechoic chamber. The second is the more recent Kevlar wall configuration, where a tensioned Kevlar sheet bounds the test section flow from the facility anechoic chamber. For both configurations, acoustic instrumentation is in the surrounding quiescent space. Both configurations are evaluated with a laser-based pulsed acoustic source, which provides unique capability for assessing the facility unsteady acoustic propagation characteristics. Metrics based on the wander and spread of the pulses are evaluated and show that measurements using Kevlar walls experience dramatically reduced unsteady effects when compared to the open-jet configuration. This leads to a corresponding improvement in coherence between microphones with the Kevlar configuration. Corrections for magnitude and phase for propagation through Kevlar as compared to open-jet propagation are calculated. While limitations in the experimental setup make quantitative analysis difficult, qualitative analysis shows Kevlar magnitude corrections similar to those determined in previous literature. Directivity effects beyond those already present for open-jet configurations are minimal. Phase corrections relative to open-jet configurations are indeterminate within the limitations of the experiment, though data suggest such corrections are not extreme. The background noise produced by the Kevlar is found to be its one drawback when compared with the open-jet configuration, showing significantly greater levels at high frequencies

    Adam Smith and the theory of punishment

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    A distinctive theory of punishment plays a central role in Smith's moral and legal theory. According to this theory, we regard the punishment of a crime as deserved only to the extent that an impartial spectator would go along with the actual or supposed resentment of the victim. The first part of this paper argues that Smith's theory deserves serious consideration and relates it to other theories such as utilitarianism and more orthodox forms of retributivism. The second part considers the objection that, because Smith's theory implies that punishment is justified only when there is some person or persons who is the victim of the crime, it cannot explain the many cases where punishment is imposed purely for the public good. It is argued that Smith's theory could be extended to cover such cases. The third part defends Smith's theory against the objection that, because it relies on our natural feelings, it cannot provide an adequate moral justification of punishment

    Cell Phones, Student Rights, and School Safety: Finding the Right Balance

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    Despite the potential instructional benefits of integrating devices such as cell phones into schools and classrooms, research reveals that their improper use can negatively impact student behaviour, learning, and well-being. This paper reviews the literature and litigation on cell phone use in schools due to controversies over cheating, cyberbullying, sexting, and searches of student cell phones. Recent studies suggested that the presence of cell phones and related technologies in classrooms could detract from students’ academic performances while contributing to higher rates of academic dishonesty and cyberbullying. The growing prevalence of cyberbullying is especially concerning because it can have severely negative, even tragic, effects on student mental health and safety. However, given the relatively discreet nature of cell phone use, regulations about their use can be difficult to enforce. After reviewing literature and litigation on the potential risks associated with inappropriate cell phone use in schools, this paper offers suggestions for educators to consider when devising or revising policies balancing students’ individual rights with their safety and well-being before ending with a brief conclusion

    Loss of oestrogen receptor alpha in long-term antioestrogen-resistant cells: reversal by a c-src inhibitor

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    Background Tamoxifen still remains the most frequently used antioestrogen for the treatment of breast cancer. However, its efficacy is often limited by the emergence of acquired resistance and it has been suggested that, in some instances, this may involve oestrogen receptor (ER) loss. This study addresses this issue by examining long-term tamoxifen treatment of breast cancer cells and identifies that progressive ER loss does occur, leading to greatly increased aggressive tumour cell behaviour. Encouragingly, even after 30 months treatment, ER loss is reversible by a c-src inhibitor. Our data therefore provide a new model to study the cellular mechanisms associated with antihormone promoted ER loss and its possible prevention/reversal by signal transduction inhibitors. Methods Using quantitative PCR based on SYBR Green fluorescence, the expression of total ERα mRNA and its constituent mRNA variants were quantified in MCF7 cells and in our in vitro developed tamoxifen-resistant breast cancer cells (TamR), which have been cultured in the presence of tamoxifen for 30 months. Specific PCR amplification of all ERα mRNA variants was possible using forward primers designed to bind specifically to the 5' untranslated regions of ERα mRNA and used separately with a common reverse primer that anneals to the 5' end of the protein encoding region of exon 1 of ERα cDNA. Expression of ERα protein was assessed by western blot and immunohistochemistry. Results In MCF7 cells, the ERα mRNA isoforms A, B and C were detected as the most predominant variants, with C ERα mRNA showing the highest expression level. In TamR cells, about a 40% fall in total ERα mRNA was observed in comparison with MCF7 cells and was most apparent for the C variant. Extension of the tamoxifen treatment period to 30 months produced a further dramatic decrease in ERα mRNA (all variants) and protein levels, resulting in ER negativity being recorded in >90% of the cells by immunohistochemistry. These cells show increased levels of phosphorylated Erk 1&2, AKT, PKCα and src, and are highly aggressive in their growth behaviour, with increased cell motility and invasiveness. Treatment of the cells with the demethylating agent 5-azacytidine did not restore ERα expression, suggesting that epigenetic alterations are unlikely to be responsible for the reduced ER levels. However, Affymetrix data in the TamR cells showed that some positive regulators of ER expression, such as p53 and Foxo3A, are downregulated during the development of the resistant phenotype and their continued absence may contribute to the progressive ER loss. Significantly, pathway inhibitor studies revealed c-src to be an important regulator of ER loss, since its inhibition rapidly restored ER levels. Conclusion Our data indicate that considerable ER loss can occur during antihormonal treatment of breast cancer cells and that this can lead to a more aggressive phenotype. Encouragingly, however, even after 30 months exposure to tamoxifen, the process is reversible by inhibition of c-src. These data suggest that combinations of antihormones with signal transduction inhibitors could retain ER functions in treated cells and prevent a drift towards more aggressive cancer cell behaviour

    Experimental Study of Wake / Flap Interaction Noise and the Reduction of Flap Side Edge Noise

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    The effects of the interaction of a wake with a half-span flap on radiated noise are examined. The incident wake is generated by bars of various widths and lengths or by a simplified landing gear model. Single microphone and phased array measurements are used to isolate the effects of the wake interaction on the noise radiating from the flap side edge and flap cove regions. The effects on noise of the wake generator's geometry and relative placement with respect to the flap are assessed. Placement of the wake generators upstream of the flap side edge is shown to lead to the reduction of flap side edge noise by introducing a velocity deficit and likely altering the instabilities in the flap side edge vortex system. Significant reduction in flap side edge noise is achieved with a bar positioned directly upstream of the flap side edge. The noise reduction benefit is seen to improve with increased bar width, length and proximity to the flap edge. Positioning of the landing gear model upstream of the flap side edge also leads to decreased flap side edge noise. In addition, flap cove noise levels are significantly lower than when the landing gear is positioned upstream of the flap mid-span. The impact of the local flow velocity on the noise radiating directly from the landing gear is discussed. The effects of the landing gear side-braces on flap side edge, flap cove and landing gear noise are shown

    Ablation debris control by means of closed thick film filtered water immersion

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    The performance of laser ablation generated debris control by means of open immersion techniques have been shown to be limited by flow surface ripple effects on the beam and the action of ablation plume pressure loss by splashing of the immersion fluid. To eradicate these issues a closed technique has been developed which ensured a controlled geometry for both the optical interfaces of the flowing liquid film. This had the action of preventing splashing, ensuring repeatable machining conditions and allowed for control of liquid flow velocity. To investigate the performance benefits of this closed immersion technique bisphenol A polycarbonate samples have been machined using filtered water at a number of flow velocities. The results demonstrate the efficacy of the closed immersion technique: a 93% decrease in debris is produced when machining under closed filtered water immersion; the average debris particle size becomes larger, with an equal proportion of small and medium sized debris being produced when laser machining under closed flowing filtered water immersion; large debris is shown to be displaced further by a given flow velocity than smaller debris, showing that the action of flow turbulence in the duct has more impact on smaller debris. Low flow velocities were found to be less effective at controlling the positional trend of deposition of laser ablation generated debris than high flow velocities; but, use of excessive flow velocities resulted in turbulence motivated deposition. This work is of interest to the laser micromachining community and may aide in the manufacture of 2.5D laser etched patterns covering large area wafers and could be applied to a range of wavelengths and laser types

    Experimental Study of Noise Shielding by a NACA 0012 Airfoil

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    The effects of sound source location, Mach number and angle of attack on the shielding of a laser-induced sound source by a NACA 0012 airfoil are examined. The sound source is a small plasma generated by a high energy, laser beam focused to a point. In-flow microphone measurements are acquired in the midspan plane of the airfoil over a broad range of streamwise stations, and shielding levels are calculated over different frequency ranges from the measurements acquired with and without the airfoil installed. Shielding levels are shown to increase as the source is positioned closer to the mid-chord of the airfoil, and to significantly decrease with increasing flow Mach number, except when the source is positioned near the leading edge of the airfoil. Both with and without flow, changes in angle of attack are associated with a corresponding shift of the shadow region. Finally, the effects of multipath signals, observer distance and signal scatter on the measured shielding levels are discussed
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