Natural Barrier Assessment and Modeling for Fish Communities in Delaware Water Gap National Recreation Area

Natural barriers may play an important role in structure and composition of stream fish habitat. Determining the effects of natural barriers on fish communities is important for understanding ecological processes that may occur throughout barrier-affected habitats. Additionally, modeling the likelihood of natural barrier occurrence using spatial data can reduce survey effort in the field and make management of fisheries in barrier-affected systems more efficient. I surveyed 446 natural barriers within the Delaware Water Gap National Recreation Area using a standardized field protocol to assess passability for fishes. I measured natural barriers individually based upon individual morphology and developed a scoring system to determine difficulty for fish passage. Fish communities were then sampled at 65 paired sites for richness and density upstream and downstream of natural barriers. The results were analyzed using pair-wise comparisons for upstream and downstream sites and showed significant species richness differences between sites separated by barriers while both brook and brown trout densities showed little to no differences among sites with and without barriers present. I modeled barrier occurrence across the study area using spatial data variables and developed rules criteria for prediction of natural barrier occurrence hot spots. Slope, flow accumulation number (watershed area) and soil type were found to be important for predicting natural barrier occurrence within our study area. Higher slopes increased the likelihood of natural barrier occurrence while lower drainage area had a similar effect. Soil types with highly erodible, rocky compositions associated with steep slopes also increased the odds of natural barrier incidence

Quantum entanglement and fixed-point bifurcations

How does the classical phase space structure for a composite system relate to the entanglement characteristics of the corresponding quantum system? We demonstrate how the entanglement in nonlinear bipartite systems can be associated with a fixed point bifurcation in the classical dynamics. Using the example of coupled giant spins we show that when a fixed point undergoes a supercritical pitchfork bifurcation, the corresponding quantum state - the ground state - achieves its maximum amount of entanglement near the critical point. We conjecture that this will be a generic feature of systems whose classical limit exhibits such a bifurcation.Comment: v2: Structure of the paper changed for clarity, reduced length, now 9 pages with 6 figure

Quantum Entanglement and Fixed-Point Bifurcations

How do the classical dynamics of a composite system relate to the entanglement characteristics of the corresponding quantum system? We show that entanglement in nonlinear bipartite systems can be associated with a fixed point bifurcation in the classical description. In a non dissipative system a fixed point corresponds to a quantum stationary state, usually a ground state. Using the example of coupled giant spins we show that, when the fixed point undergoes a supercritical pitchfork bifurcation, the corresponding quantum state achieves a maximum amount of entanglement. By way of contrast, we consider a molecular BEC system that experiences a different kind of bifurcation and does not exhibit a peak in the entanglement corresponding to the bifurcation parameter

Approaching the adiabatic timescale with machine-learning

The control and manipulation of quantum systems without excitation is challenging, due to the complexities in fully modeling such systems accurately and the difficulties in controlling these inherently fragile systems experimentally. For example, while protocols to decompress Bose-Einstein condensates (BEC) faster than the adiabatic timescale (without excitation or loss) have been well developed theoretically, experimental implementations of these protocols have yet to reach speeds faster than the adiabatic timescale. In this work, we experimentally demonstrate an alternative approach based on a machine learning algorithm which makes progress towards this goal. The algorithm is given control of the coupled decompression and transport of a metastable helium condensate, with its performance determined after each experimental iteration by measuring the excitations of the resultant BEC. After each iteration the algorithm adjusts its internal model of the system to create an improved control output for the next iteration. Given sufficient control over the decompression, the algorithm converges to a novel solution that sets the current speed record in relation to the adiabatic timescale, beating out other experimental realizations based on theoretical approaches. This method presents a feasible approach for implementing fast state preparations or transformations in other quantum systems, without requiring a solution to a theoretical model of the system. Implications for fundamental physics and cooling are discussed.Comment: 7 pages main text, 2 pages supporting informatio

Economies of Affect: Memory, Emotion and International Politics

Streaming video requires RealPlayer to view.The University Archives has determined that this item is of continuing value to OSU's history.Ross is working on a book, Economies of Affect: Memory, Emotion, and International Politics, which puts forward a new perspective on passion in international politics. He sees political passion as emotion-laden environments, or “circulations of affect,” and explores these circulations of affect in three areas: ethnic conflict and nationalism in Rwanda and Yugoslavia in the 1990s; institutions concerned with justice after a conflict, such as war-crimes trials and truth commissions; and public responses to terrorism after 9/11.Ohio State University. Mershon Center for International Security StudiesWeb page announcement; streaming video; event photo

Success in Sectoral Export Promotion and Economic and Environmental Indicators : A Multisectoral Modelling Analysis

UK policymakers are seeking to use the levers of a more active industrial policy to develop economic opportunities, including through new and expanded trading opportunities. At the same time, the UK Government has committed to a net zero greenhouse gas emissions target by 2050. While increases in exports are expected to raise economic activity, it is unclear what impact this will have on UK energy use and emissions. With a main plank of the UK strategy the development of "Sector Deals", it is unknown whether this is also true for specific industrial sectors. We examine this empirically in a multisectoral Computable General Equilibrium model of the UK that captures the interdependence between economic activity, energy use and emissions. Our results suggest that while economic outcomes move in the desired direction there are mixed impacts on energy use, UK territorial industrial emissions, and the energy- and emissions-intensity of the UK economy. Notably, we identify instances where growing exports in specific sectors helps to meet the objectives of both the Clean Growth Strategy and Industrial Strategy

Entrepreneurship and the Spatial Context: Evidence on the Location of Continuing Entrepreneurial Activity in Scotland

Small growing firms are widely recognised to be a key determinant of economic growth, regional prosperity and sustainable development. This thesis investigates the role of continuing entrepreneurial activity, defined by the annual rate of new VAT registered businesses within Scotland in an attempt to identify the key determinants that underpin its development and hence the contribution of small growing firms to the Scottish economy.A review of the theoretical and empirical literature reveals that the role of continuing entrepreneurship within Scotland is imperfectly understood, particularly at sub-regional level, and the empirical analysis undertaken in this thesis represents a step towards greater understanding in this area.The role of the regional environment is investigated by testing a number of hypotheses reflecting the local socio-economic characteristics of a region and the extent to which these factors are able to explain variation in rates of continuing entrepreneurial activity. Panel data models are constructed for 32 regions over a 10 year period from which a variety of hypotheses are tested and conclusions drawn.On the basis of the quantitative results and supporting qualitative interviews the research findings show that differences in rates of continuing entrepreneurial activity can most significantly be explained by population growth an indicator of local demand conditions and by the number of existing small businesses an indicator of attitudes and culture towards entrepreneurship. Human capital, access to finance and the presence of urbanisation economies were also found to significantly explain rates of continuing entrepreneurship across Scottish regions.On the basis of the results reported in this study, enterprise policy should attempt to address the entrepreneurial deficit that exists between regions and be focussed on the creation of a positive culture towards entrepreneurship in Scotland. This should involve the continued development of institutions and levers that are capable of providing an environment which encourages and actively supports an entrepreneurial culture in order to promote economic growth, job creation and higher levels of investment

Entanglement Sharing and Decoherence in the Spin-Bath

The monogamous nature of entanglement has been illustrated by the derivation of entanglement sharing inequalities - bounds on the amount of entanglement that can be shared amongst the various parts of a multipartite system. Motivated by recent studies of decoherence, we demonstrate an interesting manifestation of this phenomena that arises in system-environment models where there exists interactions between the modes or subsystems of the environment. We investigate this phenomena in the spin-bath environment, constructing an entanglement sharing inequality bounding the entanglement between a central spin and the environment in terms of the pairwise entanglement between individual bath spins. The relation of this result to decoherence will be illustrated using simplified system-bath models of decoherence.Comment: 5 pages, 1 figure v2: 6 pages 2 figures, additional example and reference