Transforming Power Relationships: Leadership, Risk, and Hope. IHS Political Science Series No. 135, May 2013

Chronic communal conflicts resemble the prisoner’s dilemma. Both communities prefer peace to war. But neither trusts the other, viewing the other’s gain as its own loss, so potentially shared interests often go unrealized. Achieving positive-sum outcomes from apparently zero-sum struggles requires a kind of riskembracing leadership. To succeed leaders must: a) see power relations as potentially positive-sum; b) strengthen negotiating adversaries instead of weakening them; and c) demonstrate hope for a positive future and take great personal risks to achieve it. Such leadership is exemplified by Nelson Mandela and F.W. de Klerk in the South African democratic transition. To illuminate the strategic dilemmas Mandela and de Klerk faced, we examine the work of Robert Axelrod, Thomas Schelling, and Josep Colomer, who highlight important dimensions of the problem but underplay the role of risk-embracing leadership. Finally we discuss leadership successes and failures in the Northern Ireland settlement and the Israeli-Palestinian conflict

Climate Change and Dam Owner Liability in Rhode Island

Increasing precipitation associated with climate change is affecting dam operation and hazards in Rhode Island. Flooding caused by increased precipitation or extreme weather events can cause dam failure or upstream or downstream flooding, resulting in loss of life and property. These losses can result in liability, which may vary based on the dam owner and its purpose. This study assists dam owners and the public in understanding the potential liabilities that may arise as a result of flooding from extreme weather events. Section one provides a background of dam hazards in Rhode Island in the context of climate change. Section two introduces the statutory, common law, and constitutional claims that may be brought against a dam owner after a flood. Section three applies these potential liabilities to illustrate how they may apply to different types of dams and dam owners. Section four evaluates Rhode Island law in the context of state laws from the northeast region, focusing on the application of statutory liability, strict liability and negligence standards, and liability for drawdown

A Semi-Analytic dynamical friction model that reproduces core stalling

We present a new semi-analytic model for dynamical friction based on Chandrasekhar's formalism. The key novelty is the introduction of physically motivated, radially varying, maximum and minimum impact parameters. With these, our model gives an excellent match to full N-body simulations for isotropic background density distributions, both cuspy and shallow, without any fine-tuning of the model parameters. In particular, we are able to reproduce the dramatic core-stalling effect that occurs in shallow/constant density cores, for the first time. This gives us new physical insight into the core-stalling phenomenon. We show that core stalling occurs in the limit in which the product of the Coulomb logarithm and the local fraction of stars with velocity lower than the infalling body tends to zero. For cuspy backgrounds, this occurs when the infalling mass approaches the enclosed background mass. For cored backgrounds, it occurs at larger distances from the centre, due to a combination of a rapidly increasing minimum impact parameter and a lack of slow moving stars in the core. This demonstrates that the physics of core-stalling is likely the same for both massive infalling objects and low-mass objects moving in shallow density backgrounds. We implement our prescription for dynamical friction in the direct summation code NBODY6 as an analytic correction for stars that remain within the Roche volume of the infalling object. This approach is computationally efficient, since only stars in the inspiralling system need to be evolved with direct summation. Our method can be applied to study a variety of astrophysical systems, including young star clusters orbiting near the Galactic Centre; globular clusters moving within the Galaxy; and dwarf galaxies orbiting within dark matter halos.Comment: 16 pages, 21 figures, Accepted for publication in MNRA

A semi-analytic dynamical friction model for cored galaxies

We present a dynamical friction model based on Chandrasekhar's formula that reproduces the fast inspiral and stalling experienced by satellites orbiting galaxies with a large constant density core. We show that the fast inspiral phase does not owe to resonance. Rather, it owes to the background velocity distribution function for the constant density cores being dissimilar from the usually-assumed Maxwellian distribution. Using the correct background velocity distribution function and the semi-analytic model from Petts et al. (2015), we are able to correctly reproduce the infall rate in both cored and cusped potentials. However, in the case of large cores, our model is no longer able to correctly capture core-stalling. We show that this stalling owes to the tidal radius of the satellite approaching the size of the core. By switching off dynamical friction when rt(r) = r (where rt is the tidal radius at the satellite's position) we arrive at a model which reproduces the N-body results remarkably well. Since the tidal radius can be very large for constant density background distributions, our model recovers the result that stalling can occur for Ms/Menc << 1, where Ms and Menc are the mass of the satellite and the enclosed galaxy mass, respectively. Finally, we include the contribution to dynamical friction that comes from stars moving faster than the satellite. This next-to-leading order effect becomes the dominant driver of inspiral near the core region, prior to stalling.Comment: 13 pages, 12 figures, resubmitted to MNRAS after responding to feedback from the refere

Poking fun at the surface: exploring touch-point overloading on the multi-touch tabletop with child users

In this paper a collaborative game for children is used to explore touch-point overloading on a multi-touch tabletop. Understanding the occurrence of new interactional limitations, such as the situation of touch-point overloading in a multi-touch interface, is highly relevant for interaction designers working with emerging technologies. The game was designed for the Microsoft Surface 1.0 and during gameplay the number of simultaneous touch-points required gradually increases to beyond the physical capacity of the users. Studies were carried out involving a total of 42 children (from 2 different age groups) playing in groups of between 5-7 and all interactions were logged. From quantitative analysis of the interactions occurring during the game and observations made we explore the impact of overloading and identify other salient findings. This paper also highlights the need for empirical evaluation of the physical and cognitive limitations of interaction with emerging technologies

The Limits of Self-Reliance: Emerson, Slavery, and Abolition

In the 1841 essay “Self-Reliance” Ralph Waldo Emerson presupposed a democratic society of free and equal individuals – an idealized America with a veil drawn over racial slavery. As his own commitment to the antislavery cause deepened over time Emerson sought to reconcile his ideal of self-reliance with organized political action necessary to fight slavery.Recent scholarship has corrected the previously dominant image of Emerson as detached from politics and indifferent to abolitionism. But even as he participated in it, Emerson saw antislavery activism as a distraction from his own proper work of freeing “imprisoned spirits, imprisoned thoughts, far back in the brain of man.” Abolitionists, with their single-minded pursuit of a cause, seemed to Emerson to have only a “platform existence, and no personality.” Emerson’s philosophy of Self-Reliance privileged individual over collective action, and personal experience over concern for distant evils. Emerson was most successful in synthesizing self-reliance with abolitionism when he urged resistance to the Fugitive Slave Law: individuals who resisted the law displayed self-reliance of the kind Emerson celebrated. He also admired the self-reliance of individual fugitive slaves, despite his doubts about the capacities of the black race in general and his ranking Anglo-Saxons over other races and peoples.Beyond resistance to the Fugitive Slave Law, Emerson’s philosophy of Self-Reliance provided less clear guidance for fighting slavery, and Emerson himself vibrated among several contradictory strategies. His support for peaceful, compensated emancipation within an intact Union was irreconcilable with his support for the violent measures of John Brown, whom he celebrated as the model of American self-reliance.In the 1860 essay “Fate” Emerson reformulates the ideal of self-reliance in a way that reflects the escalating sectional crisis: only through cold-eyed recognition of necessity, he argues, can one preserve a measure of self-reliance in a world that frustrates our will. This reformulation of self-reliance is more suited to human beings living through an inescapable political crisis, and in that respect an advance over the 1841 version. But it depends for its success on clearer comprehension of political causality than Emerson ever achieved

Explanation, geometry, and conspiracy in relativity theory

I discuss the debate between dynamical versus geometrical approaches to spacetime theories, in the context of both special and general relativity, arguing that (a) the debate takes a substantially different form in the two cases; (b) different versions of the geometrical approach—only some of which are viable—should be distinguished; (c) in general relativity, there is no difference between the most viable version of the geometrical approach and the dynamical approach. In addition, I demonstrate that what have previously been dubbed two ‘miracles’ of general relativity admit of no resolution from within general relativity, on either the dynamical or ‘qualified’ geometrical approaches, modulo some possible hints that the second ‘miracle’ may be resolved by appeal to recent results regarding the ‘geodesic principle’ in GR

INshade: The Structure of a synergistic approach to product design

The objective of this thesis is to demonstrate a synergistic approach to the design of a consumer product, INshade

Estimates of Marine Mammal, Sea Turtle, and Seabird Mortality in the California Drift Gillnet Fishery for Swordfish and Thresher Shark, 1996–2002

Estimates of incidental marine mammal, sea turtle, and seabird mortality in the California drift gillnet fishery for broadbill swordfish, Xiphias gladius, and common thresher shark, Alopias vulpinus, are summarized for the 7-year period, 1996 to 2002. Fishery observer coverage was 19% over the period (3,369 days observed/17,649 days fished). An experiment to test the effectiveness of acoustic pingers on reducing marine mammal entanglements in this fishery began in 1996 and resulted in statistically significant reductions in marine mammal bycatch. The most commonly entangled marine mammal species were the short-beaked common dolphin, Delphinus delphis; California sea lion, Zalophus californianus; and northern right whale dolphin, Lissodelphis borealis. Estimated mortality by species (CV and observed mortality in parentheses) from 1996 to 2002 is 861 (0.11, 133) short-beaked common dolphins; 553 (0.16, 103) California sea lions; 151 (0.25, 31) northern right whale dolphins; 150 (0.21, 27) northern elephant seals, Mirounga angustirostris; 54 (0.41, 10) long-beaked common dolphins, Delphinus capensis; 44 (0.53, 6) Dall’s porpoise, Phocoenoides dalli; 19 (0.60, 5) Risso’s dolphins, Grampus griseus; 11 (0.71, 2) gray whales, Eschrichtius robustus; 7 (0.83, 2) sperm whales, Physeter macrocephalus; 7 (0.96, 1) short-finned pilot whales, Globicephala macrorhychus; 12 (1.06, 1) minke whales, Balaenoptera acutorostrata; 5 (1.05, 1) fin whales, Balaenoptera physalus; 11 (0.68, 2) unidentified pinnipeds; 33 (0.52, 4) leatherback turtles, Dermochelys coriacea; 18 (0.57, 3) loggerhead turtles, Caretta caretta; 13 (0.73, 3) northern fulmars, Fulmarus glacialis; and 6 (0.86, 2) unidentified birds