Bistability through triadic closure

We propose and analyse a class of evolving network models suitable for describing a dynamic topological structure. Applications include telecommunication, on-line social behaviour and information processing in neuroscience. We model the evolving network as a discrete time Markov chain, and study a very general framework where, conditioned on the current state, edges appear or disappear independently at the next timestep. We show how to exploit symmetries in the microscopic, localized rules in order to obtain conjugate classes of random graphs that simplify analysis and calibration of a model. Further, we develop a mean field theory for describing network evolution. For a simple but realistic scenario incorporating the triadic closure effect that has been empirically observed by social scientists (friends of friends tend to become friends), the mean field theory predicts bistable dynamics, and computational results confirm this prediction. We also discuss the calibration issue for a set of real cell phone data, and find support for a stratified model, where individuals are assigned to one of two distinct groups having different within-group and across-group dynamics.

What GPs need to know about palliative-care drugs: ketamine

This is the first in a short series of articles that focus on what GPs should consider when monitoring and prescribing specialist-initiated palliative-care drugs. This first article summarises the key issues for patients receiving ketamine.

Do we need different frameworks to explain infant MNEs from developing countries?

I argue that the initial set of firm-specific assets (FSAs) act as an envelope for the early stages of internationalization of multinational enterprises (MNEs) (of whatever nationality) AND THAT there is a threshold LEVEL of FSAs that IT must possess for such international expansion to be SUCCESSFUL. I also argue that the initial FSAs of an MNE tend to be constrained by the location-specific (L) assets of the home country. However, beyond different initial conditions, there are few obvious reasons to insist that INFANT developing country MNEs are of unique character THAN ADVANCED ECONOMY MNEs, and I predict that as they evolve, the observable differences between the two groups will diminish. Successful firms will increasingly explore internationalization, but there is also no reason to believe that this is likely to happen disproportionately from the developing countries.

Why UK public lawyers need to be legal and political theorists

My aim in this article is to encourage UK public lawyers to engage with contemporary debates in legal, political and constitutional theory. My argument is motivated by three related concerns. First, there is an extricable link between these disciplines: behind every proposition of public law can be found a theory of law, govenment, the state and so on; secondly, public lawyers have historically neglected or fudged theory in their work; finally, a growing number of public lawyers are now using cutting-edge legal and political theories to fashion radical new understandings of the British constitution: other (more conservative-minded) public lawyers have no option, I argue, but to answer these new challenges. I illustrate my argument with reference to debates about Parliamentary sovereignty, the constitutional foundations of judicial review, political constitutionalism, and judicial deference.

What GPs need to know about palliative-care drugs : methadone

This is the second in a short series of articles that focus on what GPs should consider when monitoring and prescribing specialist‐initiated palliative‐care drugs. Here, the authors summarise the key issues around the use of methadone for pain management.

On the need for a new playing die

We model the rolling of a standard die, using a Markov matrix. Though a die may be called ‘fair’, its initial position influences a roll’s outcome. This being undesirable, a simple solution is proposed.

3D cloud reconstructions: evaluation of scanning radar scan strategy with a view to surface shortwave radiation closure

The ability of six scanning cloud radar scan strategies to reconstruct cumulus cloud fields for radiation study is assessed. Utilizing snapshots of clean and polluted cloud fields from large eddy simulations, an analysis is undertaken of error in both the liquid water path and monochromatic downwelling surface irradiance at 870 nm of the reconstructed cloud fields. Error introduced by radar sensitivity, choice of radar scan strategy, retrieval of liquid water content (LWC), and reconstruction scheme is explored. Given an in␣nitely sensitive radar and perfect LWC retrieval, domain average surface irradiance biases are typically less than 3 W m␣2 ␣m␣1, corresponding to 5–10% of the cloud radiative effect (CRE). However, when using a realistic radar sensitivity of ␣37.5 dBZ at 1 km, optically thin areas and edges of clouds are dif␣cult to detect due to their low radar re-ectivity; in clean conditions, overestimates are of order 10 W m␣2 ␣m␣1 (~20% of the CRE), but in polluted conditions, where the droplets are smaller, this increases to 10–26 W m␣2 ␣m␣1 (~40–100% of the CRE). Drizzle drops are also problematic; if treated as cloud droplets, reconstructions are poor, leading to large underestimates of 20–46 W m␣2 ␣m␣1 in domain average surface irradiance (~40–80% of the CRE). Nevertheless, a synergistic retrieval approach combining the detailed cloud structure obtained from scanning radar with the droplet-size information and location of cloud base gained from other instruments would potentially make accurate solar radiative transfer calculations in broken cloud possible for the first time.