Factors affecting conventional and molecular detection of <i>Bacillus anthracis</i> in the environment and the stability of <i>B. anthracis</i> identification plasmids PX01 and PX02 <i>in vitro</i>

Conventional and molecular methods for the improved detection of B. anthracis in environmental material were studied. A system was developed which combines a selective enrichment broth with two-phase concentration using polyethylene glycol and potassium phosphate to form the two immiscible phases.The enrichment broth alone, based on polymyxin B sulphate, lysozyme, EDTA and thallous acetate, which comprise PLET agar (PLETA), allowed the selective recovery of B. anthracis from a mixture of B. anthracis and closely related B. cereus. When soil was added to the broth, however, B. anthracis was rapidly overgrown by other naturally occurring Bacillus species. Recovery of B. anthracis was improved by using semi-solid PLET broth or by adding chelating agents or the monobactam antibiotic aztreonam to the broth. The combination of chemicals required for optimal recovery of B. anthracis varied according to the composition of the soil. Use of the two-phase concentration system showed that in soil B. anthracis spores are generally attached to soil particles and need to be separated before they can be concentrated. Separation was achieved by pre-soaking the soil in water.The sensitivity of standard PLETA is approximately 5- 50 spores per gram of soil depending on the sample composition. The system finally recommended for the most reliable and sensitive detection of spores in soil achieved an average 25 fold greater sensitivity than PLETA.Further enrichment of the B. anthracis concentrate obtained using the optimised enrichment method allowed the PCR detection of B. anthracis DNA. The sensitivity of the PCR was affected by the composition of the soil. In the absence of inhibition the PCR detection limit was approximately 10 - 100 spores per gram. A multiplex PCR was developed which targets DNA from pXO1, pX02 and the B. anthracis chromosome. The PCR allowed the rapid identification of colonies suspected of being B. anthracis. In addition to being essential for the definitive identification of B. anthracis, the ability to determine the presence of virulence plasmids in B. anthracis has reduced the need to use animals for virulence tests.Attenuated pX01+/pX02- or pX01-/pX02- strains of B. anthracis are occasionally found in the environment. Naturally occurring pX01-/pX02- derivatives have not been isolated. No other plasmid DNA has been identified in B. anthracis. To examine the nature of the stability of pX01 and pX02 in B. anthracis, the effect of selective pressure for non-indigenous plasmid DNA that had been introduced into B. anthracis was studied. A plasmid based on the minimal replicon of pAMß 1 (pAEX-5E, 5.8. kb) was found to be stable in pX01+/pX02- and pX01-/pX02+ derivatives of B. anthracis for more than 100 generations of growth. In the pX01+/pX02- and pX01+/pX02- derivatives of B. anthracis, pAEX-5E was expelled within 105 culture generations. Loss of pAEX-5E was most rapid in the pX01+/pX02- derivative. Plasmids pXOI and pX02 both remained stable under selection pressure for pAEX-5E, and in the pX01+/pX02- derivative retention of pX01 led to a reduction in growth rate. This indicates that, in the absence of pX02, B. anthracis will endure a significant metabolic compromise in order to retain pX01.This study has provided extensive new information about the selective recovery of B. anthracis. in environmental material and novel'data about the stability of identity plasmids pXO1 and pX02 under selective pressure for non-indigenous plasmid DNA

iRobot Corporations Intellectual Property: Accounting For Research And Development Under U.S. GAAP Versus IFRS

Founded by MIT scientists in 1990, iRobot Corporation designed, developed, and sold consumer and military robots to help people complete dull, dirty or dangerous tasks in real-world situations. The purpose of this case study is to stimulate discussion about intellectual property and how it should be measured and reported. Under U.S. generally accepted accounting principles (GAAP), iRobot reported no asset related to their internally generated intellectual property despite over 20 years of intensive research in robotics. In contrast, international financial reporting standards (IFRS) permitted firms to treat certain research and development (R&amp;D) activities as an asset. By comparing U.S. GAAP and IFRS treatments of R&amp;D, we provide an interesting example of the range of potential financial reporting effects across alternative accounting methods. Further, the case requires that students wrestle with the implications of moving from more rule-based accounting (U.S. GAAP) to more principles-based accounting (IFRS). How might U.S. managers, auditors, and investors likely respond? A teaching note is available

Evaluation of the Reducing Reoffending Change Fund

The aim of this evaluation was to assess the extent to which the Public Social Partnerships model delivers effective mentoring services that reduce the risk of reoffending. It was carried out by Ciaran Mulholland, Jane Eunson, Lorraine Murray and Louise Bowen (Ipsos MORI Scotland) in collaboration with Professor Gill McIvor, Dr Margaret Malloch, Professor Bill Whyte, Dr Steve Kirkwood and Professor Fergus McNeill

Self-Referential Probability and Rationality

This thesis argues for attitudes an agent ought to adopt towards two problematic examples of probabilistic self-reference. In particular, I look at a case of self-referential probability I refer to as the Probabilistic Liar, due to its similarities to the Liar paradox. The Probabilistic Liar emerges when an agent's credence can act as evidence for the truth of the proposition. Examples of self-reference turn out to be problematic for traditional Bayesian accounts of rationality. I develop an account of how rational agents ought to respond to the Probabilistic Liar by suspending judgment. Suspended judgment is an attitude more naturally talked about in traditional all-or-nothing belief models. I argue for suspended judgment in a credal framework and in particular that suspended judgment is a determinate attitude that should be represented by imprecise credences. This gives a principled way of weakening the requirement that a rational agent's degrees of beliefs ought to be probabilistically coherent. Once a solution to the Probabilistic Liar has been given a new question emerges. Can we give another example of problematic probabilistic self-reference in terms of the suspended judgement attitude? That is, can we give a Revenge problem. I explore how a Revenge problem can be generated for my account and how a rational agent can respond by having indeterminate attitudes. Finally, I argue that both the Probabilistic Liar and Revenge problems are cases of indeterminacy. I then look at the normative question of what attitude an agent ought to adopt towards cases of indeterminacy. Drawing on the attitudes I have argued for in the thesis, I argue for a pluralist answer to the normative question

Evaluation of the Reducing Reoffending Change Fund

The independent evaluation of the Reducing Reoffending Change Fund (RRCF) assessed the extent to which the Public Social Partnership (PSP) model delivers effective mentoring services that reduce the risk of reoffending and support reintegration, and concluded that there is a strong case for the continuation and expansion of mentoring services