Collisional Processes in Extrasolar Planetsimal Disks - Dust Clumps in Fomalhaut's Debris Disk

This paper presents a model for the outcome of collisions between planetesimals in a debris disk and assesses the impact of collisional processes on the structure and size distribution of the disk. The model is presented by its application to Fomalhaut's collisionally replenished dust disk; a recent 450 micron image of this disk shows a clump embedded within it with a flux ~5 per cent of the total. The following conclusions are drawn: (i) SED modelling is consistent with Fomalhaut's disk having a collisional cascade size distribution extending from bodies 0.2 m in diameter down to 7 micron-sized dust. (ii) Collisional lifetime arguments imply that the cascade starts with planetesimals 1.5-4 km in diameter. Any larger bodies must be predominantly primordial. (iii) Constraints on the timescale for the ignition of the cascade are consistent with these primordial planetesimals having a distribution that extends up to 1000km, resulting in a disk mass of 5-10 times the minimum mass solar nebula. (iv) The debris disk is expected to be intrinsically clumpy, since planetesimal collisions result in dust clumps. The intrinsic clumpiness of Fomalhaut's disk is below current detection limits, but could be detectable by future observatories such as the ALMA, and could provide the only way of determining the primordial planetesimal population. (v) The observed clump could have originated in a collision between two runaway planetesimals, both larger than 1400 km diameter. It is unlikely that we should witness such an event unless both the formation of these runaways and the ignition of the collisional cascade occurred within the last ~10 Myr. (vi) Another explanation for Fomalhaut's clump is that ~5 per cent of the planetesimals in the ring are trapped in 1:2 resonance with a planet orbiting at 80 AU.Comment: 21 pages, 13 figures, accepted by MNRA

Nineteenth-century law, literature and opium

It is not news to suggest that the law treated drugs like opium differently in the nineteenth century compared to today. These days, opium falls within the category of psychoactive drugs, for the purposes of the Psychoactive Substances Act 2016. This is because it 'produces a psychoactive effect in a person... by stimulating or depressing the person's central nervous system... [thereby] affect[ing] the person's mental functioning or emotional state' (section 2(2).[i] There was no equivalent provision in any nineteenth-century law. The suggestion here is that the law of the time-specifically, the law in England-was incapable of regulating the use of such drugs because lawmakers did not have a conception of what "mental functioning" was; and, without such an idea, they had no basis upon which to seek to control the impact of the drugs. Expressed differently, without an understanding of the mind of the legal subject, those applying the law were limited in their capacity to understand the threats, posed by opium, to that subject's mind. While the law was almost completely silent on this drug, popular culture was not. In this article I will sample a number of literary works that referred to opium use in order to explore the popular understanding of opium in English culture-including texts by Thomas De Quincey, Wilkie Collins and Arthur Conan Doyle. Taken together, a particular trajectory of attitudes may be deduced. A key benefit of looking at these examples is evident in the assessment that 'novelists are quick to respond to the movement of our times, they know that we are ready to analyse our inner experience with an intimacy that our forefathers would have felt to be intolerable' (Terman, 1919: ix). I will demonstrate that these authors, in turn, presage the changes to the regulation of drugs in the early twentieth century

Registers of artefacts of creation—from the late Medieval Period to the 19th Century

This paper offers a new perspective on the “development” of the intellectual property regimes in the United Kingdom. The system put in place under the 1875 Trade Marks Act may be seen as the last of a sequence of earlier “technologies” that sought to administer the creative endeavours of (sections of) the English population. Prior to the trade mark registration (that included examination) there was the registration of designs that did not require examination but was necessary for the protection of the right. In the eighteenth century, patent specifications were lodged with the Crown via a process that was much more involved than that was instituted for designs in the nineteenth century. Before that, books had to be enrolled with the Stationers’ Company before they could be printed. And, in what may be seen as an earlier attempt at the centralised regulation of artefacts of expression, the Rolls of Arms (maintained by the King of Arms) was repository of coats of arms for English nobility. An exploration of these different technologies of regulation, in their socio-political context, will offer new insight into the antecedents, and limits, of the registration systems that are now common across the intellectual property world

The Ties that Bind: Virginia Woolf, Leslie Stephen and Ancestral Mountains

This article examines Virginia Woolf’s late short story, ‘The Symbol’, which takes as its focus the problem of writing the mountain landscape. Not only is the mountain vulnerable to misrepresentation in being “elevated” to the function of a literary symbol, for Woolf it is also freighted with the overbearing weight of her father’s mountaineering legacy, both on the slopes and on the written page. Read in the light of the Alpine exploits of her father (Sir Leslie Stephen), this article presents ‘The Symbol’ not as a minor work on the peripheries of the writer’s oeuvre, but as an important vehicle through which Woolf is able to confront not only her ambivalent relationship with her late father and his legacy, but also the ontological complexities of representing the mountain in creative fiction

Taking the Human Out of the Regulation of Road Behaviour

Autonomous vehicles (‘AVs’) are likely to pose a significant challenge to the regulation of road behaviour in the medium to long term. The extent of that challenge depends, in part, on the categorisation of the change that they represent. This article, through taking an expansive regulatory approach, argues that the replacement of the human driver, by a machine, is not as radical as it may appear. Using Black’s notion of decentred regulation, the article concludes that the role of the human decision-maker is only a relatively small part of the overall system that guides behaviour on the roads. The infrastructure, the design of the cars, the associated systems around insurance and enforcement intersect to the extent that the ‘human’ aspect of current drivers is of lesser relevance to the regulatory efforts. This is not to say that the transition to an all-autonomous fleet will be simple; instead, the claim is that the reoriented perspective offered here provides a better context for the key difference between AVs and humans, being the processes by which decisions are made by each category of entity

Unpacking post-employment restraint of trade decisions: The motivators of the key players

Restraints of trade are aimed at limiting the capacity of employees to move from one job to another and taking important knowledge or techniques with them (to the detriment of the first employer). The current law focuses on the reasonableness of the clause at the time of its signing. A more detailed examination of the decisions made, by the employee, around the breach of such a clause suggests that this may not be the most effective approach. This assessment is made through a consideration of the motivators of the parties, the role of the legal tests, the risks relevant to their decisions and an examination of operation of the law itself. In short, if the goal of the regulation in this area is to limit the breach of restraints, then a focus on the decision of the employee to breach (or not) the clause may be more effective

Risk models and scores for type 2 diabetes: Systematic review

This article is published under a Creative Commons Attribution Non Commercial (CC BY-NC 3.0) licence that allows reuse subject only to the use being non-commercial and to the article being fully attributed (http://creativecommons.org/licenses/by-nc/3.0).Objective - To evaluate current risk models and scores for type 2 diabetes and inform selection and implementation of these in practice. Design - Systematic review using standard (quantitative) and realist (mainly qualitative) methodology. Inclusion - criteria Papers in any language describing the development or external validation, or both, of models and scores to predict the risk of an adult developing type 2 diabetes. Data sources - Medline, PreMedline, Embase, and Cochrane databases were searched. Included studies were citation tracked in Google Scholar to identify follow-on studies of usability or impact. Data extraction - Data were extracted on statistical properties of models, details of internal or external validation, and use of risk scores beyond the studies that developed them. Quantitative data were tabulated to compare model components and statistical properties. Qualitative data were analysed thematically to identify mechanisms by which use of the risk model or score might improve patient outcomes. Results - 8864 titles were scanned, 115 full text papers considered, and 43 papers included in the final sample. These described the prospective development or validation, or both, of 145 risk prediction models and scores, 94 of which were studied in detail here. They had been tested on 6.88 million participants followed for up to 28 years. Heterogeneity of primary studies precluded meta-analysis. Some but not all risk models or scores had robust statistical properties (for example, good discrimination and calibration) and had been externally validated on a different population. Genetic markers added nothing to models over clinical and sociodemographic factors. Most authors described their score as “simple” or “easily implemented,” although few were specific about the intended users and under what circumstances. Ten mechanisms were identified by which measuring diabetes risk might improve outcomes. Follow-on studies that applied a risk score as part of an intervention aimed at reducing actual risk in people were sparse. Conclusion - Much work has been done to develop diabetes risk models and scores, but most are rarely used because they require tests not routinely available or they were developed without a specific user or clear use in mind. Encouragingly, recent research has begun to tackle usability and the impact of diabetes risk scores. Two promising areas for further research are interventions that prompt lay people to check their own diabetes risk and use of risk scores on population datasets to identify high risk “hotspots” for targeted public health interventions.Tower Hamlets, Newham, and City and Hackney primary care trusts and National Institute of Health Research

Discussant\u27s response to third party confirmation requests: A new approach utilizing an expanded field

https://egrove.olemiss.edu/dl_proceedings/1203/thumbnail.jp

Applications of the Sierpiński Triangle to Musical Composition

The present paper builds on the idea of composing music via fractals, specifically the Sierpiński Triangle and the Sierpiński Pedal Triangle. The resulting methods are intended to produce not just a series of random notes, but a series that we think pleases the ear. One method utilizes the iterative process of generating the Sierpiński Triangle and Sierpiński Pedal Triangle via matrix operations by applying this process to a geometric configuration of note names. This technique designs the largest components of the musical work first, then creates subsequent layers where each layer adds more detail