Dissolving a Partnership Efficiently

Several partners jointly own an asset that may be traded among them. Each partner has a valuation for the asset; the valuations are known privately and drawn independently from a common probability distribution. We characterize the set of all incentive-compatible and interim- individually- rational trading mechanisms, and give a simple necessary and sufficient condition for such mechanisms to dissolve the partnership ex post efficiently. A bidding game is constructed that achieves such dissolution whenever it is possible. Despite incomplete information about the valuation of the asset, a partnership can be dissolved ex post efficiently provided no single partner owns too large a share; this contrasts with Myerson and Satterthwaite's result that ex post efficiency cannot be achieved when the asset is owned by a single party.Auctions; Trading Machanisms; Efficiency; Public Goods

The application of personality patterns to assessment and treatment of male intimate partner violence

This thesis sought to understand the nature and role of personality pathology in male perpetrators of intimate partner violence (IPV) who had been referred to a group intervention program in Western Australia. The research was undertaken with a sample of 181 men, across four studies that demonstrated the diversity of personality pathology in breadth, complexity and severity among this sample of men, along with a number of associated characteristics. Study 1 used the Millon Clinical Multiaxial Inventory—Third Edition (MCMI-III) to measure personality pathology in this sample of men, who were both court-referred and self-referred to the program. The results indicated that 54% of these men reported personality profiles on the MCMI-III consistent with a personality disorder, that these men had quite diverse personality profiles, and that response bias was a significant factor. Study 2 explored whether there were differences in personality pathology, response bias or reported abuse behaviours based on whether the men had been court-referred or self-referred. The results indicated few significant differences between these two groups. Study 3 parsed the men’s MCMI-III scores to ascertain whether there were any cohesive groupings, and applied principal components analysis. This procedure demonstrated five clear and coherent factors in the group, with significant differences in personality profiles within each cluster. The study then explored differential ways to work with these five groups of men in an IPV intervention program. Study 4 examined the correlates of the five clusters using measures of interpersonal problems, self-compassion and emotional empathy. Some logical relationships were found among these variables, with the men in clusters higher in personality pathology being more likely to report higher interpersonal problem scores and lower self-compassion scores, along with higher abuse scores. This study then explored in detail the implications of these findings for assessment, treatment and policy

Development of a Pharmacodynamic Model of Murine Malaria

The rational design of antimalarial therapies has historically been compromised by a paucity of pharmacodynamic data contributing to resistance through deployment of suboptimal doses. This thesis demonstrates a modified P. berghei murine malaria model for collecting detailed in vivo pharmacodynamic data and novel in silico mathematical model enabling optimisation of dosing and combination therapy. These models contribute to preclinical knowledge and provide the potential to assist in the development of methods to optimise clinical treatment

The experiences and support needs of consultant psychiatrists following a patient-perpetrated homicide

Aims and method: To investigate the experiences and support needs of consultant psychiatrists following a patient-perpetrated homicide, an anonymous online survey was sent to all consultant psychiatrists registered as members of the UK's Royal College of Psychiatrists. / Results: Of the 497 psychiatrists who responded, 165 (33%) had experienced a homicide by a patient under their consultant care. Most respondents reported negative impacts on their clinical work (83%), mental and/or physical health (78%) or personal relationships (59%), and for some (9–12%) these were severe and long lasting. Formal processes such as serious incident inquiries were commonly experienced as distressing. Support was mainly provided by friends, family and colleagues rather than the employing organisation. / Clinical implications: Mental health service providers need to provide support and guidance to psychiatrists following a patient-perpetrated homicide to help them manage the personal and professional impact. Further research into the needs of other mental health professionals is needed

Lensing Properties of Lightlike Current Carrying Cosmic Strings

The lensing properties of superconducting cosmic strings endowed with a time dependent pulse of lightlike current are investigated. The metric outside the core of the string belongs to the $pp$--wave class, with a deficit angle. We study the field theoretic bosonic Witten model coupled to gravity, and we show that the full metric (both outside and inside the core) is a Taub-Kerr-Shild generalization of that for the static string with no current. It is shown that the double image due to the deficit angle evolves in an unambiguous way as a pulse of lightlike current passes between the source and the observer. Observational consequences of this signature of the existence of cosmic strings are briefly discussed.Comment: 21 pages, LaTeX-REVTeX, 7 figures available upon request, preprint # DAMTP-R94/1

Type 0A 2D Black Hole Thermodynamics and the Deformed Matrix Model

Recently, it has been proposed that the deformed matrix model describes a two-dimensional type 0A extremal black hole. In this paper, the thermodynamics of 0A charged non-extremal black holes is investigated. We observe that the free energy of the deformed matrix model to leading order in 1/q can be seen to agree to that of the extremal black hole. We also speculate on how the deformed matrix model is able to describe the thermodynamics of non-extremal black holes.Comment: 12 page

Characterizing SWCNT Dispersion in Polymer Composites

The new wave of single wall carbon nanotube (SWCNT) infused composites will yield structurally sound multifunctional nanomaterials. The SWCNT network requires thorough dispersion within the polymer matrix in order to maximize the benefits of the nanomaterial. However, before any nanomaterials can be used in aerospace applications a means of quality assurance and quality control must be certified. Quality control certification requires a means of quantification, however, the measurement protocol mandates a method of seeing the dispersion first. We describe here the new tools that we have developed and implemented to first be able to see carbon nanotubes in polymers and second to measure or quantify the dispersion of the nanotubes

Planet formation in self-gravitating discs

The work performed here studies particle dynamics in local two-dimensional simulations of self-gravitating accretion discs with a simple cooling law. It is well known that the structure which arises in the gaseous component of the disc due to a gravitational instability can have a significant effect on the evolution of dust particles. Previous results using global simulations indicate that spiral density waves are highly efficient at collecting dust particles, creating significant local over-densities which may be able to undergo gravitational collapse. This thesis expand on these findings, using a range of cooling times to mimic the conditions at a large range of radii within the disc. The PENCIL Code is used to solve the 2D local shearing sheet equations for gas on a fixed grid together with the equations of motion for solids coupled to the gas solely through aerodynamic drag force. The work contained here shows that spiral density waves can create significant enhancements in the surface density of solids, equivalent to 1-10cm sized particles in a disc following the profiles of Clarke (2009) around a solar mass star, causing it to reach concentrations several orders of magnitude larger than the particles mean surface density. These findings suggest that the density waves that arise due to gravitational instabilities in the early stages of star formation provide excellent sites for the formation of large, planetesimal-sized objects. These results are expanded on, with subsequent results introducing the effects of the particles self-gravity showing these concentrations of particles can gravitationally collapse, forming bound structures in the solid component of the disc

The Peter Principle Revisited: A Computational Study

In the late sixties the Canadian psychologist Laurence J. Peter advanced an apparently paradoxical principle, named since then after him, which can be summarized as follows: {\it 'Every new member in a hierarchical organization climbs the hierarchy until he/she reaches his/her level of maximum incompetence'}. Despite its apparent unreasonableness, such a principle would realistically act in any organization where the mechanism of promotion rewards the best members and where the mechanism at their new level in the hierarchical structure does not depend on the competence they had at the previous level, usually because the tasks of the levels are very different to each other. Here we show, by means of agent based simulations, that if the latter two features actually hold in a given model of an organization with a hierarchical structure, then not only is the Peter principle unavoidable, but also it yields in turn a significant reduction of the global efficiency of the organization. Within a game theory-like approach, we explore different promotion strategies and we find, counterintuitively, that in order to avoid such an effect the best ways for improving the efficiency of a given organization are either to promote each time an agent at random or to promote randomly the best and the worst members in terms of competence.Comment: final version published on Physica A, 10 pages, 4 figures, 1 table (for on-line supplementary material see the link: http://www.ct.infn.it/cactus/peter-links.html