cssi/SciSciGPT-SciSciNet huggingface dataset:
A cure for pathological behavior in games that use Minimax

Minimax has long been the standard method of evaluating game tree nodes in game-playing programs. The general assumption underlying these programs is that deepening search improves play. Recent work has shown that this assumption is not always valid; for a large class of games and evaluation functions, deepening search decreases the probability of making a correct move. This phenomena is called game tree pathology. Two structural properties of game trees have been suggested as causes of pathology: independence among the values of sibling nodes, and uniform depth of win nodes. This paper examines the relationship between uniform win depth and pathology. A game-playing program is run using two different evaluation functions. The first recognizes wins only at the bottom level, the second at various levels throughout the tree. The minimax procedure behaves pathologically when the first function is used: the second shows no such pathology. This result constitutes the first experimental evidence linking uniform win depth to pathology. The effect of not recognizing wins until the bottom of the tree on the probability of making a correct decision is also analyzed. This analysis may lead to a general characterization of pathology in terms of win distribution.
Polynomial-Time Approximation Schemes for Subset-Connectivity Problems in Bounded-Genus Graphs

We present the first polynomial-time approximation schemes (PTASes) for the following subset-connectivity problems in edge-weighted graphs of bounded-genus: Steiner tree, low-connectivity survivable-network design, and subset TSP. The schemes run in \(\mathcal{O}(n \log n)\) time for graphs embedded on both orientable and nonorientable surfaces. This work generalizes the PTAS framework from planar graphs to bounded-genus graphs: any problem that is shown to be approximable by the planar PTAS framework of Borradaile et al. (ACM Trans. Algorithms 5(3), 2009) will also be approximable in bounded-genus graphs by our extension.
New information on comet P/Halley as depicted by Giotto di Bondone and other Western artists

Artists’ depictions of comets provide the only visual evidence of historical comets, most notably of Halley’s Comet. In this paper we discuss the visual evidence of comet P/Halley at several passages through that of 1301 and compare it with descriptions and modern images. Since it was first recognized that Giotto di Bondone painted a comet in place of the Star of Bethlehem and suggested that this was a portrait of the 1301 apparition of comet Halley (Olson, 1979), a great deal of new information has come to light. We present a synopsis of the textual, visual, and astronomical evidence to support the theory that when Giotto painted his comet in the Scrovegni Chapel he was reflecting his viewing of Comet Halley in 1301.
X-ray observations of gravitational lenses

A preliminary status report is given on studies using the Einstein X-ray observations of distant clusters of galaxies that are also candidates for gravitational lenses. The studies will determine the location and surface brightness distribution of the X-ray emission from clusters associated with selected gravitational lenses. The X-ray emission comes from hot gas that traces out the total gravitational potential in the cluster, so its distribution is approximately the same as the mass distribution causing gravitational lensing. Core radii and X-ray virial masses can be computed for several of the brighter Einstein sources, and preliminary results are presented on A2218. Preliminary status is also reported on a study of the optical data from 0024+16. A provisional value of 1800 to 2200 km s−1 for the equivalent velocity dispersion is obtained. The ultimate objective is to extract the mass of the gravitational lens, and perhaps more detailed information on the distribution of matter as warranted. A survey of the Einstein archive shows that the clusters A520, A1704, 3C295, A2397, A1722, SC5029-247, A3186 and A370 have enough X-ray counts observed to warrant more detailed optical observations of arcs for comparison. Mass estimates for these clusters can therefore be obtained from three independent sources: the length scale(core radius) that characterizes the density dropoff of the X-ray emitting hot gas away from its center, the velocity dispersion of the galaxies moving in the duster potential, and gravitational bending of light by the total cluster mass. This study will allow us to compare these three techniques and ultimately improve our knowledge of cluster masses.
The OSU scheme for congestion avoidance in ATM networks: lessons learnt and extensions

Abstract The OSU scheme is a rate-based congestion avoidance scheme for asynchronous transfer mode (ATM) networks using explicit rate indication. This work was one of the first attempts to define explicit rate switch mechanisms and the resource management (RM) cell format in ATM networks. The key features of the scheme include explicit rate feedback, congestion avoidance, fair operation while maintaining high utilization, use of input rate as a congestion metric, O(1) complexity. This paper presents an overview of the scheme, presents those features of the scheme that have now become common features of other switch algorithms and discusses three extensions of the scheme.
Hierarchical decentralized network reconfiguration for smart distribution systems-Part I: Problem formulation and algorithm development

This paper presents a hierarchical decentralized agent-based network reconfiguration methodology to minimize power losses for smart distribution systems. A novel formulation of the network reconfiguration problem is given in which the switch states are the decision variables, and a single-loop branch-exchange heuristic algorithm is used to solve the optimization problem. The entire distribution system is decomposed into subsystems based on the connectivity of areas, and an individual agent is assigned to each decomposed subsystem. A two-stage method is defined for coordinating the reconfigurations of decomposed subsystems. The optimal configuration of the entire system results from collaborations of individual agents, and the decentralized approach significantly reduces the computation time. A 118-bus distribution system is used as the example to illustrate the implementation of the method. The development of a demonstration system and more detailed simulation studies are given in Part II to further illustrate the application of the proposed decentralized approach.
Non-Negative Principal Component Analysis: Message Passing Algorithms and Sharp Asymptotics

Principal component analysis (PCA) aims at estimating the direction of maximal variability of a high-dimensional data set. A natural question is: does this task become easier, and estimation more accurate, when we exploit additional knowledge on the principal vector? We study the case in which the principal vector is known to lie in the positive orthant. Similar constraints arise in a number of applications, ranging from the analysis of gene expression data to spike sorting in neural signal processing. In the unconstrained case, the estimation performances of PCA have been precisely characterized using the random matrix theory, under a statistical model known as the spiked model. It is known that the estimation error undergoes a phase transition as the signal-to-noise ratio crosses a certain threshold. Unfortunately, tools from the random matrix theory have no bearing on the constrained problem. Despite this challenge, we develop an analogous characterization in the constrained case, within a one-spike model. In particular: 1) we prove that the estimation error undergoes a similar phase transition, albeit at a different thresholds in signal-to-noise ratio that we determine exactly; 2) we prove that—unlike in the unconstrained case—the estimation error depends on the spike vector, and characterize the least favorable vectors; and 3) we show that a non-negative principal component can be approximately computed—under the spiked model—in nearly linear time. This despite the fact that the problem is non-convex and, in general, NP-hard to solve exactly.
Adolescent isolation rearing produces a prepulse inhibition deficit correlated with expression of the NMDA GluN1 subunit in the nucleus accumbens

Adolescence is a transition period during which social interaction is necessary for normal brain and behavior development. Severely abnormal social interactions during adolescence can increase the incidence of lifelong psychiatric disease. Decreased prepulse inhibition (PPI) is a quantifiable hallmark of some psychiatric illnesses in humans and can be elicited in rodents by isolation rearing throughout the adolescent transition period. PPI is a measure of sensorimotor gating in which the nucleus accumbens (Acb) is crucially involved. The Acb is comprised of core and shell subregions, which receive convergent dopaminergic and glutamatergic inputs. To gain insight into the neurobiological correlates of adolescent adversity, we conducted electron microscopic immunolabeling of dopamine D1 receptors (D1Rs) and the GluN1 subunit of glutamate NMDA receptors in the Acb of isolation-reared (IR) adult male rats. In all animals, GluN1 was primarily located in dendritic profiles, many of which also contained D1Rs. GluN1 was also observed in perisynaptic glia and axon terminals. In IR rats compared with group-reared controls, GluN1 density was selectively decreased in D1R-containing dendrites of the Acb core. Across all animals, dendritic GluN1 density correlated with average percent PPI, implicating endogenous expression of NMDA receptors of the Acb as a possible substrate of the PPI response. These results suggest that adolescent isolation dampens NMDA-mediated excitation in direct (D1R-containing) output neurons of the Acb, and that these changes influence the operational measure of PPI.
Why a Second Order Magnetic Optical Achromat Works

Abstract A design procedure for a charged particle optical system where all second order matrix elements can be made to vanish simultaneously. has been described by Brown [1]. The symmetry of the system requires all geometric second-order matrix elements to vanish. A proof is given that all chromatic second-order matrix elements will also vanish.
Information flow in trust management systems

This article proposes a systematic study of information flow in credential-based declarative authorization policies. It argues that a treatment in terms of information flow is needed to adequately describe, analyze and mitigate a class of probing attacks which allow an adversary to infer any confidential fact within a policy. Two information flow properties that have been studied in the context of state transition systems, non-interference and opacity, are reformulated in the current context of policy languages. A comparison between these properties reveals that opacity is the more useful, and more general of the two; indeed, it is shown that non-interference can be stated in terms of opacity. The article then presents an inference system for non-opacity or detectability, in Datalog-based policies. Finally, a pragmatic method is presented, based on a mild modification of the mechanics of delegation, for preventing a particularly dangerous kind of probing attack that abuses delegation of authority.
Geologic Overview of the Terrestrial Planets

The terrestrial moons and planets of our solar system are composed largely of rocky and metallic materials, and preserve geologic records. The moons of the giant planets, especially the larger moons, can be thought of as terrestrial bodies, albeit exotic ones. The terrestrial bodies are close enough in bulk physical and chemical parameters to make meaningful comparisons between them. On the other hand, they are different enough so that each one has evolved a unique geological record. Planetary geology is devoted to deciphering those records and using the information in a comparative sense to better understand the physical and chemical processes that are related to the origin and evolution of planetary interiors and surfaces.
Starbursts: Triggers and Evolution

Why do the circumnuclear (inner 1–2 kpc) regions of spirals show vastly different star formation rates (SFR) even if they have a comparable molecular gas content? Why do some develop starbursts which are intense short-lived (t ≪ 1 Gyr) episodes of star formation characterized by a high star formation rate per unit mass of molecular gas (SFR/MH2 ), which I refer to as star formation efficiency (SFE). I address these questions using high resolution (2″ or 100–200 pc) CO (J=1→0) observations from the Owens Valley Radio Observatory, optical and NIR images, along with published radio continuum (RC) and Brγ data. The sample of eleven galaxies includes the brightest nearby starbursts comparable to M82 and control non-starbursts. More detailed results are in [8] and [10].
Geodesy by radio interferometry - A critical review

The principles underlying the determination of baselines by VLBI are outlined, and the principal sources of error are discussed, together with possible means for their reduction. It is noted that previous research in this field has not addressed the pitfalls of data analysis. It is stressed that for geophysical applications, an effort should be made to automate the analysis as fully as possible in order to remove the opportunities for subjective bias. Until full automation is attained, the analysis should be conducted and completed without the analyst having any knowledge of the baseline.
The Cosmological Energy Density of Neutrinos from Oscillation Measurements

The emerging structure of the neutrino mass matrix, when combined with the primordial element abundances, places the most stringent constraint on the flavor asymmetries in the cosmological neutrino background and therefore its energy density. I review the mechanism of synchronized neutrino oscillations in the an early universe with degenerate (asymmetric) neutrino and antineutrino densities and the implications of refined measurements of neutrino parameters.
Economics of Legal History

Contents: Introduction Daniel Klerman PART I LAW AS DEPENDENT VARIABLE: EFFICIENCY AND BEYOND 1. Harold Demsetz (1967), 'Toward a Theory of Property Rights' 2. Zeynep K. Hansen and Gary D. Libecap (2004), 'The Allocation of Property Rights to Land: US Land Policy and Farm Failure in the Northern Great Plains' 3. Paul G. Mahoney (2001), 'The Political Economy of the Securities Act of 1933' 4. Daniel Klerman (2007), 'Jurisdictional Competition and the Evolution of the Common Law' PART II LAW AS INDEPENDENT VARIABLE: WOMEN'S AND MINORITY RIGHTS 5. James J. Heckman and Brook S. Payner (1989), 'Determining the Impact of Federal Antidiscrimination Policy on the Economic Status of Blacks: A Study of South Carolina' 6. John R. Lott, Jr. and Lawrence W. Kenny (1999), 'Did Women's Suffrage Change the Size and Scope of Government?' 7. Grant Miller (2008), 'Women's Suffrage, Political Responsiveness, and Child Survival in American History' PART III LAW AS INDEPENDENT VARIABLE: THE GLORIOUS REVOLUTION 8. Douglass C. North and Barry R. Weingast (1989), 'Constitutions and Commitment: The Evolution of Institutions Governing Public Choice in Seventeenth-Century England' 9. Nathan Sussman and Yishay Yafeh (2006), 'Institutional Reforms, Financial Development and Sovereign Debt: Britain 1690 - 1790' 10. Daniel M. Klerman and Paul G. Mahoney (2005), 'The Value of Judicial Independence: Evidence from Eighteenth Century England' 11. Dan Bogart (2011), 'Did the Glorious Revolution Contribute to the Transport Revolution? Evidence from Investment in Roads and Rivers' PART IV BIDIRECTIONAL HISTORIES: THE RECIPROCAL INTERACTIONS OF LAW AND SOCIETY 12. Avner Greif and David D. Laitin (2004), 'A Theory of Endogenous Institutional Change' 13. Avner Greif (2006), 'History Lessons: The Birth of Impersonal Exchange: The Community Responsibility System and Impartial Justice' 14. Claire Priest (2006), 'Creating an American Property Law: Alienability and its Limits in American History' PART V PRIVATE ORDERING 15. Robert. C. Ellickson (1989), 'A Hypothesis of Wealth-Maximizing Norms: Evidence from the Whaling Industry' 16. Karen Clay and Gavin Wright (2005), 'Order Without Law? Property Rights During the California Gold Rush' 17. Avner Greif (1989), 'Reputations and Coalitions in Medieval Trade: Evidence on the Maghribi Traders' PART VI LITIGATION AND CONTRACTING 18. Claire Priest (2001), 'Currency Policies and Legal Development in Colonial New England' 19. Daniel Klerman (2012), 'The Selection of 13th-Century Disputes for Litigation' 20. J. Mark Ramseyer (1995), 'The Market for Children: Evidence from Early Modern Japan' PART VII CRITIQUE OF THE ECONOMIC APPROACH TO LEGAL HISTORY 21. Robert W. Gordon (1984), 'Critical Legal Histories' Index
Fano Hypersurfaces and their Birational Geometry

We survey some results on the nonrationality and birational rigidity of certain hypersurfaces of Fano type. The focus is on hypersurfaces of Fano index one, but hypersurfaces of higher index are also discussed.
Information Extraction Using the Structured Language Model.

The paper presents a data-driven approach to information extraction (viewed as template lling) using the structured language model (SLM) as a statistical parser. The task of template lling is cast as constrained parsing using the SLM. The model is automatically trained from a set of sentences annotated with frame/slot labels and spans. Training proceeds in stages: rst a constrained syntactic parser is trained such that the parses on training data meet the speci ed semantic spans, then the non-terminal labels are enriched to contain semantic information and nally a constrained syntactic+semantic parser is trained on the parse trees resulting from the previous stage. Despite the small amount of training data used, the model is shown to outperform the slot level accuracy of a simple semantic grammar authored manually for the MiPad | personal information management | task.
On the power of randomization in network interdiction

In this paper, we introduce the randomized network interdiction problem that allows the interdictor to use randomness to select arcs to be removed. We model the problem in two different ways: arc-based and path-based formulations, depending on whether flows are defined on arcs or paths, respectively. We present insights into the modeling power, complexity, and approximability of both formulations.
Generalizations of Bell number formulas of Spivey and Mezo

We provide q -generalizations of Spivey’s Bell number formula in various settings by considering statistics on different combinatorial structures. This leads to new identities involving q -Stirling numbers of both kinds and q -Lah numbers. As corollaries, we obtain identities for both binomial and q -binomial coefficients. Our results at the same time also generalize recent r -Stirling number formulas of Mezo. Finally, we provide a combinatorial proof and refinement of Xu’s extension of Spivey’s formula to the generalized Stirling numbers of Hsu and Shiue. To do so, we develop a combinatorial interpretation for these numbers in terms of extended Lah distributions.
Where Has the Currency Gone? And Why? The Underground Economy and Personal Income Tax Evasion in the U.S., 1970-2008

Unaccounted for currency in the U.S. is argued to reflect the presence of widespread income tax evasion. This empirical study seeks to identify determinants of the underground economy in the U.S. in the form of federal personal income tax evasion over the period 1970-2008. In this study, we use the most recent data available on personal income tax evasion, data that are derived from the General Currency Ratio Model and measured in the form of the ratio of unreported AGI (adjusted gross income) to reported AGI. Other studies of federal income tax evasion for the U.S. are dated and do not use data this current. It is found that personal income tax evasion was an increasing function of the maximum marginal federal personal income tax rate, the percentage of federal personal income tax returns characterized by itemized deductions, and unpopular military engagements, in this case, the War in Iraq, and a decreasing function of the Tax Reform Act of 1986 (during its first two years of being implemented), the ratio of the tax free interest rate yield on high grade municipals to the interest rate yield on ten year Treasury notes (as a measure of the incentive effect of a better return to tax avoidance, which is legal), and higher audit rates of filed federal income tax returns (as a measure of risk from tax evasion) by IRS personnel.
An alternative unifying measure of welfare gains from risk-sharing

Following Lucas's (1987) standard approach, welfare gains from international risk-sharing have been measured as the percentage increase in consumption levels that leaves individuals indifferent between, autarky and risk-sharing. The author proposes to measure welfare gains as the increase in consumption growth, instead of consumption levels. When the consumption process is non-stationary, the author's proposed measure has several attractive features: it does not depend on the horizon, and it is robust to alternative specifications of the consumption stochastic processes (from geometric Brownian processes, to Orstein-Ulhenbeck mean-reverting processes), and preferences (from constant relative risk aversion preferences to Kreps-Porteus preferences). The author then uses this measure to estimate potential welfare gains from international risk-sharing for a representative U.S. consumer. The author finds that if international risk-sharing leads only to a complete elimination of aggregate consumption volatility (with no impact on consumption growth), it represents gains to a U.S. consumer of only $ 12 a year on average. But if international risk-sharing also permits an increase in consumption growth, it may have a sizable impact on welfare. Each 0.5 percentage point increase in consumption growth, represents gains to a U.S. consumer of about $ 160 a year on average.
Edges, orbifolds, and Seiberg–Witten theory

Seiberg-Witten theory is used to obtain new obstructions to the existence of Einstein metrics on 4-manifolds with conical singularities along an embedded surface. In the present article, the cone angle is required to be of the form 2…=p, p a positive integer, but we conjecture that similar results will also hold in greater generality. Recent work on Kahler-Einstein metrics by Chen, Donaldson, Sun, and others (5), (12), (13), (17), (26) has elicited wide interest in the existence and uniqueness problems for Einstein metrics with conical singularities along a submanifold of real codimension 2. This article will show that Seiberg-Witten theory gives rise to interesting obstructions to the existence of 4-dimensional Einstein metrics with conical singularities along a sur- face. These results are intimately tied to known phenomena in Kahler geometry, and reinforce the overarching principle that Kahler metrics play a uniquely privileged role in 4-dimensional Riemannian geometry, to a degree that is simply unparalleled in other dimensions. We now recall the definition (2) of an edge-cone metric on a 4-manifold. Let M be a smooth compact 4-manifold, let § ‰ M be a smoothly embedded compact surface. Near any point p 2 §, we can thus find local coordinates (x 1 ;x 2 ;y 1 ;y 2 ) in which § is given by y 1 = y 2 = 0. Given any such adapted coordinate system, we then introduce an associated transversal polar coordinate system (‰;µ;x 1 ;x 2 ) by setting y 1 = ‰cosµ and y 2 = ‰sinµ. Now fix some positive constant fl > 0. An edge-cone metric g of cone angle
Agent communication languages: rethinking the principles

Agent communication languages have been used for years in proprietary multiagent systems. Yet agents from different vendors--or even different research projects--cannot communicate with each other. The author looks at the underlying reasons and proposes a conceptual shift from individual agent representations to social interaction.
A Biography of the Magnetic Field of a Neutron Star

After some post-natal cooling, a spinning, magnetized, canonical neutron-star (NS) has a core of superconducting protons, superfluid neutrons, and degenerate extreme relativistic electrons, all surrounded by a thin highly conducting solid crust. The quantum fluids are threaded by a dense array of quantized vortex-lines which can interact strongly with a denser and much less uniform one of quantized magnetic flux-tubes. The physics of such a core predicts the evolution of a NS’s surface magnetic field and related phenomena as the star’s spin changes. Predictions include changes in NS magnetic dipole moments, anomalously small polar caps in millisecond pulsars, properties of two different families of spin-period “glitches”, and spin-down ages much greater than true ages for some pulsars. Quantitative model-based estimates for all of these are given. None are in conflict with observations.
5PM: Secure pattern matching

In this paper we consider the problem of secure pattern matching that allows single-character wildcards and substring matching in the malicious stand-alone setting. Our protocol, called 5PM, is executed between two parties: Server, holding a text of length n, and Client, holding a pattern of length m to be matched against the text, where our notion of matching is more general than traditionally considered and includes non-binary alphabets, non-binary Hamming distance and non-binary substring matching.5PM is the first secure expressive pattern matching protocol designed to optimize round complexity by carefully specifying the entire protocol round by round. 5PM requires only eight rounds in the malicious static corruptions model. In the malicious model, 5PM requires O((m+n)k2) communication complexity and O(m+n) encryptions, where m is the pattern length and n is the text length. Further, 5PM can hide pattern size with no asymptotic additional costs in either computation or bandwidth.
Value-added tax : administrative and policy issues

More than 50 countries worldwide employ a value-added tax. What are its effects on prices, exports, and investment? Is it regressive? These and other questions are answered in this collection of papers presented at a March 1990 Jakarta seminar on the VAT in Asia.
Critical role of NKT Cells in Posttransplant Alloantibody Production

We previously reported that posttransplant alloantibody production in CD8-deficient hosts is IL-4+CD4+ T cell–dependent and IgG1 isotype-dominant. The current studies investigated the hypothesis that IL-4-producing natural killer T cells (NKT cells) contribute to maximal alloantibody production. To investigate this, alloantibody levels were examined in CD8-deficient WT, CD1d KO and Jα18 KO transplant recipients. We found that the magnitude of IgG1 alloantibody production was critically dependent on the presence of type I NKT cells, which are activated by day 1 posttransplant. Unexpectedly, type I NKT cell contribution to enhanced IgG1 alloantibody levels was interferon-γ-dependent and IL-4-independent. Cognate interactions between type I NKT and B cells alone do not stimulate alloantibody production. Instead, NKT cells appear to enhance maturation of IL-4+CD4+ T cells. To our knowledge, this is the first report to substantiate a critical role for type I NKT cells in enhancing in vivo antibody production in response to endogenous antigenic stimuli.
Investigating coverage-reliability relationship and sensitivity of reliability to errors in the operational profile

The focus of this work is an investigation into the correlation between "true" reliability of a software system and the white box testing measures such as block coverage, c-uses and puses coverage. We believe that software reliability and testing measures, especially white box testing, are inherently related. Results from experiments are presented to support this belief. We also demonstrate that the estimated reliability is sensitive to the operational profile defined for the software and hence errors in the operational profile may lead to incorrect reliability estimates.
Screening Peers Softly: Inferring the Quality of Small Borrowers

This paper examines the performance of new online lending markets that rely on nonexpert individuals to screen their peers' creditworthiness. We find that these peer lenders predict an individual's likelihood of defaulting on a loan with 45% greater accuracy than the borrower's exact credit score unobserved by the lenders, who only see a credit category. Moreover, peer lenders achieve 87% of the predictive power of an econometrician who observes all standard financial information about borrowers. Screening through soft or nonstandard information is relatively more important when evaluating lower-quality borrowers. Our results highlight how aggregating over the views of peers and leveraging nonstandard information can enhance lending efficiency. This paper was accepted by Amit Seru, finance.
Fencing in the Swampland: Quantum Gravity Constraints on Large Field Inflation

In this note we show that models of natural inflation based on closed string axions are incompatible with the weak gravity conjecture (WGC). Specifically, we use T- duality in order to map the bounds on the charge-to-mass ratio of particles imposed by the WGC, to constraints on the ratio between instanton actions and axion decay constants. We use this connection to prove that if the WGC holds, even when multiple axions are present and mix with each other, one cannot have large axion decay constants while remaining in a regime of perturbative control. We also discuss the extension of the WGC to discrete symmetries and its possible impact on models with axion monodromy, and the distinction between the strong and mild versions of the WGC. We argue that, if the strong version is violated, the constraints on large field inflation can be evaded while still satisfying the mild one. Finally, we offer some speculations regarding the import of these results to the general theory of inflation.
Can Easing Concealed Carry Deter Crime

OBJECTIVE: Laws reducing hurdles to legally carrying concealed firearms are argued to have a deterrent effect on crime by increasing its perceived costs. This argument rests on the assumption that these policies will either directly or indirectly increase the perceived distribution of firearm carriers, an assumption that is as yet untested. This article tests this assumption and, in so doing, suggests testing the necessary conditions of policy can be useful when assessing outcomes is difficult. Methods: I collect survey data on the perceived number of firearm carriers across the United States and then use a hierarchical regression model to assess the impact of concealed carry policies on these perceptions, controlling for several contextual and individual-level factors. Results: The data suggest that there is no statistically discernible relationship between concealed carry policies and the public's perceptions of the number of firearm carriers. Indeed, the data suggest that the perceived density of firearm carriers is similarly uncorrelated to the number of active concealed carriers. Conclusion: The link between concealed carry policy and people's beliefs about the number of firearm carriers in their community is unidentifiable in the data. The rationale for concealed carry deterrence, however, depends on such a link existing: it assumes that potential assailants are aware of the distribution of firearm carriers in the potential victim population, but the empirical evidence presented here suggests that that assumption simply does not hold. Because beliefs over the distribution of firearm carriers are impervious to permitting policies and do not respond positively to the true distribution of carriers, the data suggest easing concealed carry cannot deter crime. Language: en
EMPIRICAL POLYCENTRICITY: THE COMPLEX RELATIONSHIP BETWEEN EMPLOYMENT CENTERS†

Our paper empirically demonstrates that employment subcenters in large urban areas have important economic relationships with each other, and not solely with the central business district (CBD). Using data from Houston, Texas, we estimate polycentric density functions and show that “total” gradients differ from gradients using only own-center coefficients. We model asymmetry by showing density is very different for centers with overlapping areas of influence. We conclude that subcenters have important yet heterogeneous linkages to each other in addition to the CBD, and that therefore the polycentric city is more complex than simply having additional centers mimicking the CBD.
Strengthening Invariants by Symbolic Consistency Testing

We describe a relatively simple method for strengthening invariants when verifying infinite-state hardware systems called symbolic consistency testing. The method requires a high-level symbolic simulator and a decision procedure for quantifier-free first-order logic. The user only needs to provide a small number of simple symbolic test vectors that expose internal inconsistencies in the system state. A verification system then uses symbolic simulation with these test vectors to strengthen the original invariant to an inductive one, which is discharged using k-step induction. The main advantage of our method is that the user input is usually very simple and intuitive, and the user does not need to be exposed to the actual complexity of the verification, which then proceeds completely automatically. The method is applied to several typical microarchitectures for cached memories.
Presidential Elections and Corruption Perceptions in Latin America

This paper argues that perceptions of corruption in Latin America exhibit predictable fluctuations in the wake of presidential turnover. Specifically, presidential elections that result in the partisan transfer of power are normally followed by a surge-and-decline pattern in perceived corruption control, with initial improvements that fade with time. The causes are multiple and stem from the removal of corrupt administrations, public enthusiasm about administrative change, and the relative lack of high-level corruption scandals in the early phases of new governments. A statistical analysis of two widely used corruption perceptions indices demonstrates the pattern for eighteen Latin American democracies from 1996 to 2010. Both indices exhibit a temporary surge (of about two years) after turnover elections, while no such change follows reelections of incumbent presidents or parties. The theory and results are relevant for understanding public opinion in Latin America and for the analysis of corruption perceptions indices.
The Central African Republic’s Infrastructure : A Continental Perspective

Between 2000 and 2005 infrastructure made a modest net contribution of less than one percentage point to the improved per capita growth performance of the Central African Republic (CAR), despite high expenses in the road sector. Raising the country's infrastructure endowment to that of the region's middle-income countries could boost annual growth by about 3.5 percentage points. Assuming that the inefficiencies are fully captured, comparing spending needs against existing spending and potential efficiency gains leaves an annual funding gap of $183 million per year. By far the largest gap exists in transport. The CAR has the potential to close this gap by raising additional public funding for infrastructure from increased fiscal receipts of various kinds. Furthermore, the CAR has not captured as much private finance for infrastructure (measured as a percentage of Gross Domestic Product, or GDP) as many of its neighbors. This scope for improvement, coupled with the prospect of an economic rebound and prudent policies, could lift the country from it fragile state back to and beyond the prosperity standards it once enjoyed.
Stochastic optimization for collision selection in high energy physics

Artificial intelligence has begun to play a critical role in basic science research. In high energy physics, AI methods can aid precision measurements that elucidate the underlying structure of matter, such as measurements of the mass of the top quark. Top quarks can be produced only in collisions at high energy particle accelerators. Most collisions, however, do not produce top quarks and making precise measurements requires culling these collisions into a sample that is rich in collisions producing top quarks (signal) and spare in collisions producing other particles (background). Collision selection is typically performed with heuristics or supervised learning methods. However, such approaches are suboptimal because they assume that the selector with the highest classification accuracy will yield a mass measurement with the smallest statistical uncertainty. In practice, however, the mass measurement is more sensitive to some backgrounds than others. This paper presents a new approach that uses stochastic optimization techniques to directly search for selectors that minimize statistical uncertainty in the top quark mass measurement. Empirical results confirm that stochastically optimized selectors have much smaller uncertainty. This new approach contributes substantially to our knowledge of the top quark's mass, as the new selectors are currently in use selecting real collisions.
For distinguishing conjugate hidden subgroups, the pretty good measurement is as good as it gets

Recently Bacon, Childs and van Dam showed that the "pretty good measurement"(PGM) is optimal for the Hidden Subgroup Problem on the dihedral group Dn in the casewhere the hidden subgroup is chosen uniformly from the n involutions. We show that,for any group and any subgroup H, the PGM is the optimal one-register experiment inthe case where the hidden subgroup is a uniformly random conjugate of H. We go on toshow that when H forms a Gel'fand pair with its parent group, the PGM is the optimalmeasurement for any number of registers. In both cases we bound the probability thatthe optimal measurement succeeds. This generalizes the case of the dihedral group, andincludes a number of other examples of interest.
Finite-dimensional representations of quantum affine algebras at roots of unity

We describe explicitly the canonical map X : Spec UE (B) -* Spec ZE, where U? (B) is a quantum loop algebra at an odd root of unity E. Here ZE is the center of UE(g) and Spec R stands for the set of all finite- dimensional irreducible representations of an algebra R. We show that Spec Z, is a Poisson proalgebraic group which is essentially the group of points of G over the regular adeles concentrated at 0 and oo. Our main result is that the image under X of Spec U,(b) is the subgroup of principal adeles. DEPARTMENT OF MATHEMATICS, HARVARD UNIVERSITY, CAMBRIDGE, MASSACHUSETTS 02138 E-mail address: beckfmath .harvard. edu DEPARTMENT OF MATHEMATICS, MASSACHUSETTS INSTITUTE OF TECHNOLOGY, CAMBRIDGE, MASSACHUSETTS 02139 E-mail address: kacImath. mit. edu This content downloaded from 207.46.13.124 on Wed, 22 Jun 2016 06:11:29 UTC All use subject to http://about.jstor.org/terms
The Accidental Administrative Law of the Medicare Program

On July 30, 1965, President Lyndon B. Johnson and Congress established the Medicare and Medicaid programs. This article traces the evolution of administrative procedures for policy-making and adjudication in the Medicare program since its inauguration. Part II of this article provides background information on the Medicare program that is relevant to Medicare’s administrative functions. Part III traces the evolution of administrative procedures for policy-making and adjudication in the Medicare program since its inauguration. Part IV addresses how some Medicare appeals systems are not meeting the needs of the program or its beneficiaries and also providers, suppliers and contractors. Finally, Part V will explore the collaborative approaches to policy-making that have occurred since 2000 and, in particular, in the Patient Protection and Affordable Care Act.
Using Hierarchical Linear Modeling to Examine Dynamic Performance Criteria Over Time

The selection literature has long debated the theoretical and practical significance of dynamic criteria. Recent research has begun to explore the nature of individual performance over time. This study contributes to this body of research through a hierarchical linear modeling analysis of dynamic criteria. The purpose of this study was to investigate the role of ability in explaining initial job performance, as well as the rate of improvement-or performance trend-among a sample of 408 sewing machine operators over a 24 week period. The results of a hierarchical linear modeling analysis suggest that ability measures are differentially related to initial performance and performance improvement trend.
Stellar Forensics with the Supernova-GRB Connection

Long-duration gamma-ray bursts (GRBs) and Type Ib/c Supernovae (SNe Ib/c) are amongst nature's most magnificent explosions. While GRBs launch relativistic jets, SNe Ib/c are core-collapse explosions whose progenitors have been stripped of their hydrogen and helium envelopes. Yet for over a decade, one of the key outstanding questions is which conditions lead to each kind of explosion and death in massive stars. Determining the fates of massive stars is not only a vibrant topic in itself, but also impacts using GRBs as star formation indicators over distances of up to 13 billion light-years and for mapping the chemical enrichment history of the universe. This article reviews a number of comprehensive observational studies that probe the progenitor environments, their metallicities and the explosion geometries of SN with and without GRBs, as well as the emerging field of SN environmental studies. Furthermore, it discusses SN 2008D/XRT 080109 that was discovered serendipitously with the Swift satellite via its X-ray emission from shock breakout, and that has generated great interest amongst both observers and theorists while illustrating a novel technique for stellar forensics. The article concludes with an outlook on how the most promising venues of research - with the existing and upcoming innovative large-scale surveys such as the Palomar Transient Factory and LSST - will shed new light on the diverse deaths of massive stars.
Change alone is unchanging: Continuous context-aware adaptation of service-based systems for smart cities and communities

Service-based systems have to deal with highly dynamic environments in which they must often operate. Consider for instance the case of smart cities and communities, i.e., communities of people who actively participate to the creation and use of ICT-based solutions to improve their quality of life within their own city or region. Within a smart city and community, the context in which applications must operate continuously changes, as well as the situation, the accessibility to (ICT-based) services, the people, their interactions, requirements, and preferences. Moreover, most often, the only way applications can react to such changing environment is at run-time, since we cannot predict a priori different situations, requirements, interactions, and availability of (ICT) services. Continuous context-aware and incremental adaptation becomes therefore the key enabling property for the delivery of ICT based value added services to cope with the dynamics of the continuously changing environment. In my talk, I will present some of the compelling needs for context aware incremental adaptation in the case of service-based applications for smart cities and communities. I will discuss some alternative approaches, some lessons learned from applications we have been working with in this field, and the still many related open research challenges.
The Underground Economy in the U.S.A: Preliminary New Evidence on the Impact of Income Tax Rates (and Other Factors)on Aggregate Tax Evasion, 1975-2008

This empirical study seeks to identify determinants of the underground economy in the U.S. in the form of aggregate federal personal income tax evasion over the period 1975-2008, with a specific focus upon the impact of higher federal income tax rates on tax evasion. In this study, we use the most recent data available on aggregate personal income tax evasion, data that are derived from the General Currency Ratio Model and measured in the form of the ratio of unreported AGI to reported AGI. Most other studies of federal income tax evasion for the U.S. do not use data this current. It is found that the impact of increases in the federal income tax rate on aggregate personal income tax evasion may, on balance, be ambiguous, possibly suggesting that the income effect is negative and outweighs the positive substitution effect for the representative taxpayer. It is also found that the degree of aggregate personal income tax evasion may be an increasing function of the percentage of federal personal income tax returns characterized by itemized deductions and a decreasing function of the Tax Reform Act of 1986 (during the first two years of implementation), the ratio of the tax free interest rate yield on high grade municipals to the interest rate yield on ten year Treasury notes, and higher audit rates of filed federal income tax returns (as a measure of risk from tax evasion) by IRS personnel. Finally, unpopular wars may provide a secondary benefit for and therefore act as an inducement for greater tax evasion. JEL Codes: G18, G28, H26 Keywords: tax evasion; substitution effect; income effect; incentives; disincentives
Cohesiveness and Organizational Citizenship Behavior: A Multilevel Analysis Using Work Groups and Individuals:

Using a theory-based multilevel framework, we examined the potential relationships of two organizational citizenship behavior (OCB) dimensions with individual- and group-level measures. The individual-level measures used were employee job satisfaction and organizational commitment; the group-level measure used was work group cohesiveness. The sample for the study was drawn from eight service sector organizations. Hierarchical linear modeling (HLM) analyses revealed that employees in more cohesive work groups displayed greater amounts of courtesy than would have been predicted based only on their job satisfaction or organizational commitment. Further, the relationship between employee job satisfaction and the amount of courtesy displayed was stronger in the more cohesive groups. Such results were not obtained when conscientiousness was the focal OCB. Implications of our results, as well as use of HLM in multilevel investigations, are discussed.!
Transitioning from low-income growth to high-income growth: is there a middle-income trap?

Is there a “middle-income trap”? Theory suggests that the determinants of growth at low and high income levels may be different. If countries struggle to transition from growth strategies that are effective at low income levels to growth strategies that are effective at high income levels, they may stagnate at some middle income level; this phenomenon can be thought of as a “middle-income trap.” Defining income levels based on per capita gross domestic product relative to the United States, we do not find evidence for (unusual) stagnation at any particular middle income level. However, we do find evidence that the determinants of growth at low and high income levels differ. These findings suggest a mixed conclusion: middle-income countries may need to change growth strategies in order to transition smoothly to high income growth strategies, but this can be done smoothly and does not imply the existence of a middle-income trap.