The New Theory of Strategic Voting

This is an analysis of strategic voting under qualified majority voting. Existing formal analyses of the plurality rule predict complete coordination of strategic voting: a strict interpretation of Duverger's Law. This conclusion is rejected. Unlike previous models, the popular support for each option is not commonly certain. Agents base their vote on both public and private signals of popular support. When private signals are the main source of information, the uniquely stable equilibrium entails only limited strategic voting and hence partial coordination. This is due to the surprising presence of negative feedback --- strategic voting is a self-attenuating phenomenon. The theory leads to the conclusion that multi-candidate support in a plurality electoral system is perfectly consistent with rational voting behaviour.

Dynamic government performance: honeymoons and crises of confidence

We use a formal theoretical framework to explore the interplay between a government's longevity and its performance. Ministers perform well when their careers are valuable; this is so when the government's duration is expected to be long; the government's survival depends on its popularity; and, finally, that popularity depends on its ministers performance. The feedback loop between performance and longevity means that multiple rational-expectations equilibria can arise: Ministers work hard for a popular government, but divert efforts elsewhere if they believe the government is doomed; these alternatives are both self-fulfilling prophecies. However, the presence of (perhaps small) random events that buffet the performance and popularity of a government is sufficient to pin down a unique equilibrium. We explore the dynamics that arise: A crisis of confidence involving the rapid collapse of a government's performance is sparked when a sequence of negative shocks push the popularity of the government below a unique critical threshold

Leading the Party:Coordination, Direction, and Communication

Party activists face a coordination problem: a critical mass (a barrier tocoordination) must advocate a single policy alternative if the party is tosucceed. The need for direction is the degree to which the merits of thealternatives respond to the underlying mood of the party. An individual'sability to assess the mood is his sense of direction. These factors combine toform an index of both the desirability and the feasibility of leadership: wecall this index Michels' Ratio. A sovereign party conference gives way toleadership by an individual or oligarchy if and only if Michels' Ratio issufficiently high. Leadership enhances the clarity of intra-partycommunication, but weakens the response of policy choices to the party'smood.

The Qualities of Leadership:Direction, Communication, and Obfuscation

Party activists wish to (i) advocate the best policy and yet (ii) unify behind a commonparty line. An activist's understanding of his environment is based on the speeches ofparty leaders. A leader's influence, measured by the weight placed on her speech,increases with her judgement on policy (sense of direction) and her ability to conveyideas (clarity of communication). A leader with perfect clarity of communication enjoysgreater influence than one with a perfect sense of direction. Activists can choose howmuch attention to pay to leaders. A necessary condition for a leader to monopolize theagenda is that she is the most coherent communicator. Sometimes leaders attract moreattention by obfuscating their messages. A concern for party unity mitigates thisincentive; when activists emphasize following the party line, they learn more about theirenvironment.

Using phase Doppler anemometry & high speed imaging to analyze MDI spray plume dynamics

Characterisation of inhalation aerosols focuses in the first instance on aerodynamic particle size, which is measured using cascade impactors. The aerosol must contain large quantities of particles in the respirable size range 1-5 m. Deposition on impactor stages depends on the velocity of the particles as well as their size. Pressurised metered dose inhalers (pMDIs) produce very fast-moving spray plumes, so it is important to understand the dynamic nature of droplet formation processes and spray plumes. This paper presents a selection of findings from an optical diagnostics study of aerosol plumes generated by a Bespak 630 series actuator in conjunction with a series of HFA134a placebo formulations containing ethanol up to 20% w/w. Spray plume dynamics in the vicinity of the spray orifice and further downstream were characterised using phase-Doppler anemometry (PDA), high-speed imaging and particle image velocimetry (PIV). The findings of the work demonstrate the complementary capabilities of these instruments. PDA provides simultaneous values of mean droplet size and velocity (and their associated statistics), but it is time-consuming to sample a sufficient number of locations to characterise the rapidly changing spray plume. PIV, on the other hand, provides information on entire flow fields albeit at lower spatial and temporal resolution. PIV and PDA data for the velocity of various spray plumes were found to be in good agreement, which validates both techniques. High-speed imaging also captures the overall characteristics of the plume. The diffraction limit of the optical configuration used for imaging is around 10 m, so it is not possible to observe respirable droplets individually. However, the dynamics and trajectories of larger droplets can be studied. These larger droplets were found to be produced by highly localised atomisation processes, so the resulting droplets can be easily missed or undersampled in PDA surveys. These results suggest that further research on pMDI sprays with these combined tools will provide useful insights into the processes responsible for changes in droplet size and velocity, and can be expected to make a major contribution to improving the development of the next generation of pMDI inhalers

Transient aerodynamic atomisation model to predict aerosol droplet size of pressurised metered dose inhalers (pMDI)

Pressurised metered dose inhalers (pMDI) produce large numbers of droplets with size of smaller than 5 μm to treat asthma and other pulmonary diseases. The mechanism responsible for droplet generation from bulk propellant liquid is poorly understood, mainly because the small length scales and short time scales make it difficult to characterise transient spray formation events. This paper describes the development and findings of a numerical atomisation model to predict droplet size of pharmaceutical propellants from first principles. In this model, the velocity difference between propellant vapour and liquid phase inside spray orifice leads to formation of wave-like instabilities on the liquid surface. Two variants of the aerodynamic atomisation model are presented based on assumed liquid precursor geometry: (1) cylindrical jet-shaped liquid ligaments surrounded by vapour annulus, (2) annular liquid film with vapour flow in the core. The growth of instabilities on the liquid precursors surfaces and the size of the subsequently formed droplets is predicted by numerical solutions of dispersion equations. The droplet size predictions were compared with Phase Doppler Anemometry (PDA) data and the predictions were in good agreement with the number mean diameter D10, which is representative of the respirable droplets. The temporal behaviour of droplet size production was captured consistently well during the period of the first 95% of the propellant mass emission. The outcome of our modelling activities also suggests that, in addition to saturated vapour pressure of the propellant, its viscosity and surface tension are also key properties that govern pMDI droplet size

Multi-physics theoretical approach to predict pMDI spray characteristics

Continued success in treatment of asthma and COPD requires development of new formulations, which may alter spray characteristics and atomisation quality of atomiser devices such as pMDI. Fundamental understanding of the underlying physical phenomena and the dynamic nature of pMDI aerosol plumes is essential to maintain pMDI device atomisation quality. In this paper, we describe a simulation of pMDI aerosol generation and plume development using a model of two-phase flow and atomisation of HFA134/ethanol formulation. The model is implemented within a CFD simulation to study the dynamic aerosol development and predict spray velocity and temperature. The CFD result shows plume velocity slows down over a relatively short distance and droplet temperature settles at a steady value of 291 K approximately at a distance of 30 mm from the spray orifice. This means that droplets reach their final size before reaching the exit of the mouthpiece

Social acceptability of a marine protected area: The case of Reunion Island

This paper examines variations in social acceptability of a Marine Protected Area (MPA) prior to implementation. The influence of a number of factors, including socio-economic characteristics, perception of coral resources state of health and attitudes towards non-compliance with regulations are analysed. During May 2006, 640 questionnaires were distributed to school children around Reunion Island, Western Indian Ocean, for completion by their parents, following an informal educational activity made in school. From a 73% (n = 469) response rate, results showed that 78% of participants were in favour of the MPA. Analysis further identified that those supportive of the MPA were generally from higher socio-professional categories, had a negative perception of the coral reef ecosystem's health and were not originally from Reunion. In contrast, locals (born in Reunion) from lower socio-professional categories or with no employment activity and having a positive perception of the health status of coral reefs offered no opinion on the MPA. Attitudes towards enforcement and compliance highlighted that SCUBA divers, fishers and jet skiers attributed a higher value to the protection of the coral reef environment through enforcement of MPA regulations than to their own use of the coral reef resource. When asked about the use of penalties to deter non-compliance, swimmers were awarded the lowest fines, followed by SCUBA divers, fishers then jet skiers being awarded the highest fines. Thus, the more severe the act of non-compliance by a resource user group was perceived to be, the more these users themselves disapproved of non-compliant behaviour and supported use of high penalties. The survey design through focusing on school children's parents, demonstrated a simple and cost-effective method for data collection while providing environmental education, which could be employed in similar case studies elsewhere

Microsomal prostaglandin E2 synthase-1 is induced by conditional expression of RET/PTC in thyroid PCCL3 cells through the activation of the MEK-ERK pathway

RET/PTC rearrangements are believed to be tumor-initiating events in papillary thyroid carcinomas. We identified microsomal prostaglandin E2 synthase-1 (mPGES-1) as a RET/PTC-inducible gene through subtraction hybridization cloning and expression profiling with custom microarrays. The inducible prostaglandin E2 (PGE2) biosynthetic enzymes cyclooxygenase-2 (COX-2) and mPGES-1 are up-regulated in many cancers. COX-2 is overexpressed in thyroid malignancies compared with benign nodules and normal thyroid tissues. Eicosanoids may promote tumorigenesis through effects on tumor cell growth, immune surveillance, and angiogenesis. Conditional RET/PTC1 or RET/PTC3 expression in PCCL3 thyroid cells markedly induced mPGES-1 and COX-2. PGE2 was the principal prostanoid and up-regulated (by approximately 60-fold), whereas hydroxyeicosatetraenoic acid metabolites were decreased, consistent with shunting of prostanoid biosynthesis toward PGE2 by coactivation of the two enzymes. RET/PTC activated mPGES-1 gene transcription. Based on experiments with kinase inhibitors, with PCCL3 cell lines with doxycycline-inducible expression of RET/PTC mutants with substitutions of critical tyrosine residues in the kinase domain, and lines with inducible expression of activated mutants of H-RAS and MEK1, RET/PTC was found to regulate mPGES-1 through Shc-RAS-MEK-ERK. These data show a direct relationship between activation of a tyrosine kinase receptor oncogene and regulation of PGE2 biosynthesis. As enzymes involved in prostanoid biosynthesis can be targeted with pharmacological inhibitors, these findings may have therapeutic implications

Cold Collision Frequency Shift of the 1S-2S Transition in Hydrogen

We have observed the cold collision frequency shift of the 1S-2S transition in trapped spin-polarized atomic hydrogen. We find $\Delta \nu_{1S-2S} = -3.8(8)\times 10^{-10} n Hz cm^3$, where $n$ is the sample density. From this we derive the 1S-2S s-wave triplet scattering length, $a_{1S-2S}=-1.4(3)$ nm, which is in fair agreement with a recent calculation. The shift provides a valuable probe of the distribution of densities in a trapped sample.Comment: Accepted for publication in PRL, 9 pages, 4 PostScript figures, ReVTeX. Updated connection of our measurement to theoretical wor