7,624 research outputs found

    A Normalized Scoring Model for Law School Competitions

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    Although the focus in this Article is moot court scoring, one can envision many other instances of law school assessment in which such a normalization problem arises. Law review competitions also involve different sets of graders, whose subjective determinations must be reasonably commensurate to make fair comparisons. Even more intriguing, although presenting a more complicated problem, law school grades suffer the same normalization concern. Courses feature material with different degrees of difficulty, attract different pools of students, and are taught by different instructors. Yet, class rank and graduation honors are ultimately calculated under the assumption that all grades are commensurate. In this Article, we propose a statistical method for normalizing scores in the moot court context

    Random polynomials, random matrices, and LL-functions

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    We show that the Circular Orthogonal Ensemble of random matrices arises naturally from a family of random polynomials. This sheds light on the appearance of random matrix statistics in the zeros of the Riemann zeta-function.Comment: Added background material. Final version. To appear in Nonlinearit

    Statistical theory of the continuous double auction

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    Most modern financial markets use a continuous double auction mechanism to store and match orders and facilitate trading. In this paper we develop a microscopic dynamical statistical model for the continuous double auction under the assumption of IID random order flow, and analyze it using simulation, dimensional analysis, and theoretical tools based on mean field approximations. The model makes testable predictions for basic properties of markets, such as price volatility, the depth of stored supply and demand vs. price, the bid-ask spread, the price impact function, and the time and probability of filling orders. These predictions are based on properties of order flow and the limit order book, such as share volume of market and limit orders, cancellations, typical order size, and tick size. Because these quantities can all be measured directly there are no free parameters. We show that the order size, which can be cast as a nondimensional granularity parameter, is in most cases a more significant determinant of market behavior than tick size. We also provide an explanation for the observed highly concave nature of the price impact function. On a broader level, this work suggests how stochastic models based on zero-intelligence agents may be useful to probe the structure of market institutions. Like the model of perfect rationality, a stochastic-zero intelligence model can be used to make strong predictions based on a compact set of assumptions, even if these assumptions are not fully believable.Comment: 36 pages, 40 figures, RevTex4, submitted to Quantitative Financ

    Effects of Neutron Irradiation on Carbon Doped MgB2 Wire Segments

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    We have studied the evolution of superconducting and normal state properties of neutron irradiated Mg(B.962_{.962}C.038_{.038})2_2 wire segments as a function of post exposure annealing time and temperature. The initial fluence fully suppressed superconductivity and resulted in an anisotropic expansion of the unit cell. Superconductivity was restored by post-exposure annealing. The upper critical field, Hc2_{c2}(T=0), approximately scales with Tc_c starting with an undamaged Tc_c near 37 K and Hc2_{c2}(T=0) near 32 T. Up to an annealing temperature of 400 o^ oC the recovery of Tc_c tends to coincide with a decrease in the normal state resistivity and a systematic recovery of the lattice parameters. Above 400 o^ oC a decrease in order along the c- direction coincides with an increase in resistivity, but no apparent change in the evolution of Tc_c and Hc2_{c2}. To first order, it appears that carbon doping and neutron damaging effect the superconducting properties of MgB2_2 independently

    Anti-correlation and subsector structure in financial systems

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    With the random matrix theory, we study the spatial structure of the Chinese stock market, American stock market and global market indices. After taking into account the signs of the components in the eigenvectors of the cross-correlation matrix, we detect the subsector structure of the financial systems. The positive and negative subsectors are anti-correlated each other in the corresponding eigenmode. The subsector structure is strong in the Chinese stock market, while somewhat weaker in the American stock market and global market indices. Characteristics of the subsector structures in different markets are revealed.Comment: 6 pages, 2 figures, 4 table

    Origins and composition of fine atmospheric carbonaceous aerosol in the Sierra Nevada Mountains, California

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    In this paper we report chemically resolved measurements of organic aerosol (OA) and related tracers during the Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX) at the Blodgett Forest Research Station, California from 15 August–10 October 2007. OA contributed the majority of the mass to the fine atmospheric particles and was predominately oxygenated (OOA). The highest concentrations of OA were during sporadic wildfire influence when aged plumes were impacting the site. In situ measurements of particle phase molecular markers were dominated by secondary compounds and along with gas phase compounds could be categorized into six factors or sources: (1) aged biomass burning emissions and oxidized urban emissions, (2) oxidized urban emissions (3) oxidation products of monoterpene emissions, (4) monoterpene emissions, (5) anthropogenic emissions and (6) local methyl chavicol emissions and oxidation products. There were multiple biogenic components that contributed to OA at this site whose contributions varied diurnally, seasonally and in response to changing meteorological conditions, e.g. temperature and precipitation events. Concentrations of isoprene oxidation products were larger when temperatures were higher during the first half of the campaign (15 August–12 September) due to more substantial emissions of isoprene and enhanced photochemistry. The oxidation of methyl chavicol, an oxygenated terpene emitted by ponderosa pine trees, contributed similarly to OA throughout the campaign. In contrast, the abundances of monoterpene oxidation products in the particle phase were greater during the cooler conditions in the latter half of the campaign (13 September–10 October), even though emissions of the precursors were lower, although the mechanism is not known. OA was correlated with the anthropogenic tracers 2-propyl nitrate and carbon monoxide (CO), consistent with previous observations, while being comprised of mostly non-fossil carbon (>75%). The correlation between OA and an anthropogenic tracer does not necessarily identify the source of the carbon as being anthropogenic but instead suggests a coupling between the anthropogenic and biogenic components in the air mass that might be related to the source of the oxidant and/or the aerosol sulfate. Observations of organosulfates of isoprene and α-pinene provided evidence for the likely importance of aerosol sulfate in spite of neutralized aerosol although acidic plumes might have played a role upwind of the site. This is in contrast to laboratory studies where strongly acidic seed aerosols were needed in order to form these compounds. These compounds together represented only a minor fraction (<1%) of the total OA mass, which may be the result of the neutralized aerosol at the site or because only a small number of organosulfates were quantified. The low contribution of organosulfates to total OA suggests that other mechanisms, e.g. NO_x enhancement of oxidant levels, are likely responsible for the majority of the anthropogenic enhancement of biogenic secondary organic aerosol observed at this site

    A theory for long-memory in supply and demand

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    Recent empirical studies have demonstrated long-memory in the signs of orders to buy or sell in financial markets [2, 19]. We show how this can be caused by delays in market clearing. Under the common practice of order splitting, large orders are broken up into pieces and executed incrementally. If the size of such large orders is power law distributed, this gives rise to power law decaying autocorrelations in the signs of executed orders. More specifically, we show that if the cumulative distribution of large orders of volume v is proportional to v to the power -alpha and the size of executed orders is constant, the autocorrelation of order signs as a function of the lag tau is asymptotically proportional to tau to the power -(alpha - 1). This is a long-memory process when alpha < 2. With a few caveats, this gives a good match to the data. A version of the model also shows long-memory fluctuations in order execution rates, which may be relevant for explaining the long-memory of price diffusion rates.Comment: 12 pages, 7 figure

    Post-polymerisation modification of bio-derived unsaturated polyester resins via Michael additions of 1,3-dicarbonyls

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    Post-polymerisation modification of α,β-unsaturated polyesters (UPEs) is useful to deliver polymers with tuneable properties and applications different from their parent backbone. Bio-derivable itaconate unsaturated polyesters, with a range of co-monomers, were modified via a heterogeneously catalysed microwave-assisted Michael addition of pendants, acetylacetone (Hacac) and dimethyl malonate (DMM), to the polymer backbones with very short reaction times. Differential scanning calorimetry analysis showed an increase in the glass-transition temperatures of most of the saturated polyesters considered. Solubility and complexation studies demonstrated metal chelating abilities of the acetylacetone pendant can be retained, even following tethering to a polyester backbone. Additionally, it is demonstrated for the first time that Michael addition with Hacac and DMM can be used to reverse Ordelt saturation, an unwanted side-reaction in the synthesis of UPEs

    A Multi Agent Model for the Limit Order Book Dynamics

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    In the present work we introduce a novel multi-agent model with the aim to reproduce the dynamics of a double auction market at microscopic time scale through a faithful simulation of the matching mechanics in the limit order book. The agents follow a noise decision making process where their actions are related to a stochastic variable, "the market sentiment", which we define as a mixture of public and private information. The model, despite making just few basic assumptions over the trading strategies of the agents, is able to reproduce several empirical features of the high-frequency dynamics of the market microstructure not only related to the price movements but also to the deposition of the orders in the book.Comment: 20 pages, 11 figures, in press European Physical Journal B (EPJB

    The Elections of 2000: Politics, Culture and Economics in North America

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    The essays in this collection are the product of a conversation among scholars, spanning national borders and disciplinary boundaries, about the increasing integration of Canada, Mexico, and the United States and the development of a “continental perspective.” This conversation has been underway for some time, reflecting the causes, challenges, and consequences of economic, cultural, and political integration in North America. The conjunction of national elections in all three of the great North American democracies in 2000 offered us the opportunity to deepen this conversation and engage in scholarly discourse from a “continental perspective.” Taken together, the essays in this book provide a vivid portrait of North American democracies at the turn of the century.https://ideaexchange.uakron.edu/elections_of_2000/1000/thumbnail.jp
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