Fearless: Aleksandra Petkova

Consistently serving the campus community, conducting new research in psychology, and leading younger students to realizations about their own roles in fighting for social Justice, Aleksandra Petkova ’14 has fearlessly pursued opportunities to promote social change all four of her years here at Gettysburg

Election Briefing No 65: Europe and the October 2011 Polish parliamentary election

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The evolution of national social dialogue in Europe under the single market, 1992-2006

This paper examines the evolution of national social dialogue (bipartite wage bargaining) across European countries. Several commentators in the 1990s expected the dismantling of national social dialogue institutions. Following the liberalisation of markets, intensification of competition, and declining union power, bargaining structures were supposed to converge to the Anglo-Saxon model of decentralised bargaining. The paper seeks to gauge the plausibility of the ‘decentralization thesis’ using novel indicators of collective bargaining centralization across the EU15. It is shown that despite the changes in product markets, flexible working, and declining union density, a generalized decentralization of bargaining did not occur. Instead, in many European cases there is a counter-trend of centralization, which casts doubt to the decentralization thesis

Interactive Vegetation Rendering with Slicing and Blending

Detailed and interactive 3D rendering of vegetation is one of the challenges of traditional polygon-oriented computer graphics, due to large geometric complexity even of simple plants. In this paper we introduce a simplified image-based rendering approach based solely on alpha-blended textured polygons. The simplification is based on the limitations of human perception of complex geometry. Our approach renders dozens of detailed trees in real-time with off-the-shelf hardware, while providing significantly improved image quality over existing real-time techniques. The method is based on using ordinary mesh-based rendering for the solid parts of a tree, its trunk and limbs. The sparse parts of a tree, its twigs and leaves, are instead represented with a set of slices, an image-based representation. A slice is a planar layer, represented with an ordinary alpha or color-keyed texture; a set of parallel slices is a slicing. Rendering from an arbitrary viewpoint in a 360 degree circle around the center of a tree is achieved by blending between the nearest two slicings. In our implementation, only 6 slicings with 5 slices each are sufficient to visualize a tree for a moving or stationary observer with the perceptually similar quality as the original model

Who is willing to deliberate, and how? Dissatisfied democrats, stealth democrats and populists in the UK: SEI Working Paper 131

This article draws on a new survey of British citizens to test the hypothesis that there are two quite distinctive types of attitude prevalent among those who are ‘disaffected’ with politics, the ‘dissatisfied democratic’ and ‘stealth democratic’ orientations, the former being more widespread in the UK. While neither manifests a high level of trust for the political elite, the dissatisfied democratic citizen is politically interested, efficacious and desires greater political participation, while the contrary is generally true of the stealth democrat. However, although stealth democrats are unwilling to engage in most forms of participation or deliberation, they are ambiguous about direct democracy, which can be attributed to the populist nature of stealth democratic attitudes

Sources of variations in total column carbon dioxide

Observations of gradients in the total CO_2 column, (CO2), are expected to provide improved constraints on surface fluxes of CO_2. Here we use a general circulation model with a variety of prescribed carbon fluxes to investigate how variations in (CO_2) arise. On diurnal scales, variations are small and are forced by both local fluxes and advection. On seasonal scales, gradients are set by the north-south flux distribution. On synoptic scales, variations arise due to large-scale eddy-driven disturbances of the meridional gradient. In this case, because variations in (CO_2) are tied to synoptic activity, significant correlations exist between (CO_2) and dynamical tracers. We illustrate how such correlations can be used to describe the north-south gradients of (CO_2) and the underlying fluxes on continental scales. These simulations suggest a novel analysis framework for using column observations in carbon cycle science

PyZX: Large Scale Automated Diagrammatic Reasoning

The ZX-calculus is a graphical language for reasoning about ZX-diagrams, a type of tensor networks that can represent arbitrary linear maps between qubits. Using the ZX-calculus, we can intuitively reason about quantum theory, and optimise and validate quantum circuits. In this paper we introduce PyZX, an open source library for automated reasoning with large ZX-diagrams. We give a brief introduction to the ZX-calculus, then show how PyZX implements methods for circuit optimisation, equality validation, and visualisation and how it can be used in tandem with other software. We end with a set of challenges that when solved would enhance the utility of automated diagrammatic reasoning.Comment: In Proceedings QPL 2019, arXiv:2004.1475