Can greater uncertainty hasten investment?

This paper examines irreversible investment in a project with uncertain returns, when there is an advantage to being the first to invest and externalities to investing when others also do so. We show that in a duopoly, greater uncertainty can actually hasten rather than delay investment, contrary to the usual outcome, due its effect on the equilibrium of the timing game between the players. In the presence of positive externalities, greater uncertainty can raise the leader's value more than the follower's; pre-emption then entails that the leader must act sooner. A switch in the pattern of equilibrium investment as uncertainty increases is also possible, which may hasten investment. These findings reinforce the importance of extending real options analysis to include strategic interactions and externalities between players

Networks, Options and Preemption

This paper examines the irreversible adoption of a technology whose returns are uncertain, when there is an advantage to being the first adopter, but a network advantage to adopting when others also adopt. There are two main results. First, conditional on adoption being sequential, the follower adopts at the incorrect point, compared with the cooperative solution. The leader adopts at the cooperative point when there is no preemption, and too early if there is preemption. Secondly, there is insufficient simultaneous adoption in equilibrium. The paper examines how these inefficiencies vary as the degree of uncertainty and network effects change. Interesting interactions between the various factors are found. For example, the analysis raises the interesting possibility that the introduction of a small amount of uncertainty can cause the first mover to adopt the technology earlier.

The Failing Firm Defence: Merger Policy and Entry

This paper considers the `failing firm defence'. Under this principle, found in most antitrust jurisdictions, a merger that would otherwise be blocked due to its adverse effect on competition is permitted when the firm to be acquired is a failing firm, and an alternative, less detrimental merger is unavailable. Competition authorities have shown considerable reluctance to accept the failing firm defence, and it has been successfully used in just a handful of cases. The paper considers the defence in a dynamic setting with uncertainty. A firm entering a market also considers its ease of exit, foreseeing that it may later wish to leave should market conditions deteriorate. By facilitating exit in times of financial distress, the failing firm defence may encourage entry sufficiently that welfare is increased overall. This view of the defence has several implications relevant to a number of merger cases. The conditions under which greater leniency is welfare-improving are examined.merger policy, failing firm defence, entry, exit

Modelling written language production in English: a Bayesian model of spelling

In English, word production (i.e., spelling) is more complex than word recognition (i.e., reading) as the relationship between graphemes and phonemes is not equally distributed. Despite this known complexity, models of spelling are largely descriptive and less sophisticated than models of reading. Furthermore, current models of spelling do not adequately explain how spelling information is learned and managed. Intriguingly, Bayesian reading models have facilitated research and development in recent years. Given the complex relationship between reading and spelling, I developed a Bayesian computational model of spelling to address these limitations. Operational validity was assessed both theoretically (i.e., conceptual and predictive validity) and empirically (i.e., data, event, and predictive validity). The model was designed to behave like a human speller based on what is currently known about spelling. The Bayesian spelling model simulates a dictation task and makes spelling decisions based on 10 parameters that are analogous to human spelling decisions. The model was trained with Queensland spelling lists based on National curriculum guidelines for grades 1 to 7, which provides data validity, and was tested with words from a computerised NAPLAN dictation task from grades 3, 5, 7, and 9 students, providing event validity. Predictive validity was examined by comparing the Bayesian spelling model responses with the NAPLAN student data. Accuracy and error data for students and for all parameters were calculated and transformed into density distributions to overcome sample size limitations, and skewed data in relation to letter frequencies. Independent-samples Bayesian t-tests compared the distributions of the model with the distributions of students for each testing grade. Results for grades 3 and 5 supported my hypotheses, showing positive evidence that there was no difference between the distributions of data from students and the distributions from expected model parameters. Although results for grades 7 and 9 supported my hypotheses for error only, accuracy data were still in alignment with the predictions of current spelling models and with Australian curriculum guidelines. My findings validate the model as spelling behaviour is effectively reproduced (i.e., empirical validation) and data are congruent with existing literature (i.e., theoretical validation). Furthermore, the progression of learning through parameter decisions aligns with known learning processes. These findings provide robust evidence that Bayesian decision making can be used to model spelling behaviour and that my model can reproduce the learning process of spelling. My model provides ample research opportunities, including investigation of early phonological learning and later morphological strategies. I suggest that further model development consider the ability to examine contractions and differentiate between homophones. Future research with the Bayesian spelling model feasibly provides a means of experimentally examining educational strategies and spelling disorders and could have implications for natural language processing. Most importantly, it is hoped that future research with the Bayesian model of spelling will highlight the important role of spelling and spelling education in everyday life

Alien Registration- Mason, Helen (Houlton, Aroostook County)

https://digitalmaine.com/alien_docs/34784/thumbnail.jp

Investigating the role of 53BP1 in regulating gene transcription.

53BP1 is a DNA damage responsive protein that plays a crucial role in checkpoint activation and DNA repair. In addition to its involvement in the cellular response to DNA damage, it has been suggested that 53BP1 can also function to regulate gene expression. 53BP1 was originally identified in a yeast two-hybrid screen for novel modulators of p53 transcriptional activity. Despite this, the role of 53BP1 in transcriptional regulation remains poorly understood. To investigate the effect of 53BP1 on cellular transcription, a microarray approach was utilised to study the gene expression patterns in cells treated with and without 53BP1 siRNA, before and after ionising radiation. Microarray analysis identified numerous genes whose expression was regulated by 53BP1 in the absence and presence of DNA damage. These data suggest that 53BP1 functions as a transcriptional regulator. In support of this, in vitro and in vivo studies have shown that 53BP1 binds to the transcriptional co-activators, CBP and p300. These findings indicate that the binding of 53BP1 to CBP and p300 may be facilitating its role as a regulator of transcription

Structural and Spectroscopic Studies into Spin Crossover Complexes and Anils

This posthumous thesis combines two literature reviews written by Helen Mason and eight papers arising from data collected by Helen during her PhD studies. Helen also synthesised most of the compounds she studied and which are reported herein. The thesis uses single crystal X-ray diffraction data combined with spectroscopic data to study spin crossover complexes and anils, Schiff bases of salicylaldehyde derivatives with aniline derivatives. The thesis is divided into two main sections. The first section examines spin crossover complexes initially through a summary of the reported literature (Chapter 1). The remainder of the section focuses on experimental studies into complexes containing (abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) ligands. Chapters 2 and 3 examine the spin crossover behaviour of Fe(abpt)2(NCS)2 polymorphs A, B and D. The spin crossover behaviour of the three polymorphs is significantly different, which is particularly interesting given that their structures are very similar. Polymorph A has a thermal spin crossover, displays LIESST (Light Induced Excited Spin-State Trapping) and undergoes pressure induced spin crossover. Polymorph B does not undergo a thermal spin crossover at ambient pressure, however under pressure it undergoes a phase transition followed by a spin crossover. Polymorph D contains two unique Fe(II) centres in the asymmetric unit one of which undergoes a thermal spin crossover and displayed LIESST, upon the application of pressure a stepped spin crossover was observed at both unique Fe(II) centres. Structural and spectroscopic data are reported. The differences in structure and intermolecular interactions are examined and set in the context of similar structures in the literature. The thermal spin crossover and LIESST behaviour of Fe(abpt)2(NCSe)2 polymorph A, which is isostructural with Fe(abpt)2(NCS)2 polymorph A, is also reported and examined both structurally and spectroscopically (Chapter 4). The concluding chapter in this section, Chapter 5, reports the structures of two polymorphs Co(abpt)2(NCS)2 and Ni(abpt)2(NCS)2 polymorph A and B, which are isostructural with the corresponding Fe(abpt)2(NCS)2 polymorphs A or B respectively. The second section begins with a literature review of selected photochromic systems which have been structurally characterised, Chapter 6. The rest of the section reports experimental studies into some anil compounds. Twenty seven N-(methoxysalicylidene)-haloaniline (halo = F, Cl or Br) derivatives were synthesised and their crystal structures determined, Chapter 7. New polymorphs were identified for two of the compounds, 4-(methoxysalicylidene)-4-fluroaniline and 3-(methoxysalicylidene)-4-chloroaniline and a temperature induced phase transition for 5-(methoxysalicylidene)-4-bromoaniline. Visual observations of their thermochromism alongside diffuse reflectance spectra are reported and linked to the observed structure, with those showing smaller interplanar angles between the ring generally tending to be more strongly thermochromic. Neutron diffraction data are also reported for two of the strongly thermochromic compounds, 5-(methoxysalicylidene)-2-chloroaniline and 5-(methoxysalicylidene)-2-bromoaniline. In Chapter 8, the structures of three di-tertiary butyl substituted anils, E)-2,4-di-tert-butyl-6-(((4-fluorophenyl)imino)methyl)phenol, (E)-2,4-di-tert-butyl-6-(((4-chlorophenyl)imino)methyl)phenol, and (E)-2,4-di-tert-butyl-6-(((4-bromophenyl)imino)methyl)phenol, are reported. Two polymorphs were identified for (E)-2,4-di-tert-butyl-6-(((4-fluorophenyl)imino)methyl)phenol, while the other two structures underwent a thermally induced phase transition. The thermochromic and photochromic behaviour of the compounds were examined using diffuse reflectance and Raman spectroscopy. In Chapter 9, the synthesis and structures of three isoxazole containing Schiff bases, (E)-2-((isoxazol-3-ylimino)methyl)phenol, (E)-2-(((5-methylisoxazol-3-yl)imino)methyl)phenol and (E)-2,4-di-tert-butyl-6-((isoxazol-3-ylimino)methyl)phenol, are reported. None of these were found to be strongly thermochromic but all three were found to be photochromic. Finally, Chapter 10 reports the structure of a new polymorph of (E)-4-bromo-2-((phenylimino)¬methyl)¬phenol. The colours of the two polymorphs at room temperature were found to be different, and both polymorphs were found to display thermochromism

Active Region Moss: Doppler Shifts from Hinode/EIS Observations

Studying the Doppler shifts and the temperature dependence of Doppler shifts in moss regions can help us understand the heating processes in the core of the active regions. In this paper we have used an active region observation recorded by the Extreme-ultraviolet Imaging Spectrometer (EIS) onboard Hinode on 12-Dec-2007 to measure the Doppler shifts in the moss regions. We have distinguished the moss regions from the rest of the active region by defining a low density cut-off as derived by Tripathi et al. (2010). We have carried out a very careful analysis of the EIS wavelength calibration based on the method described in Young et al. (2012). For spectral lines having maximum sensitivity between log T = 5.85 and log T = 6.25 K, we find that the velocity distribution peaks at around 0 km/s with an estimated error of 4-5 km/s. The width of the distribution decreases with temperature. The mean of the distribution shows a blue shift which increases with increasing temperature and the distribution also shows asymmetries towards blue-shift. Comparing these results with observables predicted from different coronal heating models, we find that these results are consistent with both steady and impulsive heating scenarios. However, the fact that there are a significant number of pixels showing velocity amplitudes that exceed the uncertainty of 5 km s$^{-1}$ is suggestive of impulsive heating. Clearly, further observational constraints are needed to distinguish between these two heating scenarios.Comment: 21 pages (single column), 7 figures, Accepted for Publication in The Astrophysical Journa